Subject: Re: Student Question... From: "Jan D. Froom" froom@............. Date: Wed, 29 Sep 1999 17:19:34 -0700 Thank you for the replies to our student question. Per Ken's suggestion, we'd like to let the students pursue this a bit more by collecting sand from various beaches around the world, and testing their hypotheses. If any of you have access to beach sand, and would be willing to send it to us, we'll let you see the results of the kids work. Sharon Redford is the teacher, and she says they need about a 1/2 cup. Mail to: Sharon Redford South Valley Junior High School of Science and Technology 385 IOOF Avenue Gilroy, CA 95020 USA THANKS again! Jan "Kenneth J. De Nault" wrote: > I would commend the student for his hypothesis and ask him to propose some > method for testing his hypothesis, such as examining the iron content of sand > from Alaska. You might also ask him to make a prediction concerning the iron > content of sands as one goes toward the south pole. > > I would not tell him he is "wrong" but would encourage him to be a scientist. > All of us "scientists" have proposed "wrong" hypothesis. > > Ken De Nault. > > P.S. The "iron" content is most probably the mineral magnetite. This is a > dense, iron oxide mineral whose concentration is a function of many factors, > among which is availability in the source rock, the energy of the transport > mechanism, and the energy of the depositional environment. As a dense mineral, > it tends to be concentrated by the removal of the less dense, and generally much > more abundant, silicate minerals. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: More diamagnetism tid-bits From: meredithlamb@.............. Date: 29 Sep 1999 17:29:25 -0700 Hi all, From Robert Lamb: "Got to reviewing past editions of "HCP", (Handbook of Chem & Physics), and caught onto apparent disparagement of diamagnetism data - older copies are from turn-of-century data and CARBON WAS BEST!! (over bismuth) Then from 1970 on, HCP used French Institute data which put carbon down. Even 1997 copy here in library shows no tables of diamagnetism data, but does have nice graph of the elements only. Suspect that anisotrophism maybe involved, like many crystalline structures." Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Student Question... From: doug doug@............. Date: Wed, 29 Sep 1999 15:37:01 -0700 Jan wrote: > If any of you have access to beach sand, and would be willing to send it to us, > we'll let you see the results of the kids work. I can get some sand from Santa Cruz CA beaches. I assume it would be better to get the sand from somewhere along the unpopluated shores say between SC and SF, to avoid the human factor as much as possible (dredging effects etc). I would be interested in hearing about the test methods they use and it would also be interesting to see the results. BTW I am doing something a bit similar, using mobile wireless internet servers with GPS and monitors for CO2, CO, temp, humidity and other conditions. The idea is that as I roam around I will be always connected to the net and always collecting data. Over time the collective data will fill in a map showing the different conditions. I am doing this more as a network experiment/demo rather than for scientific purposes, but the data might be interesting to watch and graph. On a similar note at my home in the santa cruz mountains I am already monitoring temperatures inside, outside, aquariums, fridge, freezer, hottub, relative humidity inside and outside, barometer, wind speed and direction, rain guage, and aquarium conditions: temp, pH, conductivity, oxygen reduction potential. Soon to be added: absolute humidity, dewpoint, wet bulb temp, solar radition, particle counting, etc. I will show you all my sensor pages in a while, right now the system is down for some rewiring and calibration of devices. Eventually I want to internet enable an infrared spectrometer and automatically cycle through calibrations for various ambient air elements (this will be done by adding TCP/IP ethernet interfaces and using tiny uniquely addressible switches to push the buttons). Finally, I eventually want to use the same idea for automated liquid chromatography analysis of the elements in the sea water in my mini reef aquarium. Here's the aquarium now: http://207.214.112.10/video.html?select=yes Note that right now it's night on the reef, so you'll have to check it out in the daytime. You can move the camera around and zoom in close on sea anenomes, corals, sponges, feather dusters, hermit crabs, snails cleaner shrimp, and the clownfishes and sailfin tang. Also note that you are fighting over the camera so don't be surprised if it moves. Please don't walk away and leave the camera in "auto image update" mode or you'll be hammering my server (this will be fixed soon). The aquarium follows a seasonal variation of sunrise and sunset, and an incandecent bulb with dimmer simulates moonrise and set along with intensity changes for phases. Powerheads simulate tide changes every six hours, other pumps create random surges [*]. I can also invoke all of these functions over the net through a GUI, and soon the system will email me, page me, then call me if alarm states are reached, or if anyone is foolish enough to break in (which will result in ftp'd images offsite over the net). I am right now putting together a stepper motor/dispenser assembly which will automatically feed the fish, and the ultimate goal is to automate partial water changes including mixing of sea water. I have most of the parts for this and am getting really close. I still need to find a way to monitor nitrates, calcium, strontium, molydbenum, and iodine (these are additives that need to be regularly dispensed). I am also struggling with methods of powder dispensation (sea salt mix) and would love to hear any ideas as to how I might do this (assume that I have a fixed weight or volume that I want to dispense via software event). Also, if you can tell me how to effectively automate glass cleaning you will be my hero (note that I must apply forces at various angles using a long handled brush to clean the glass, the magnet based scrapers are not good enough ruling out simple linear actuation of magnetically moved scrapers :( Oh, and since I am way off topic for the list ... maybe I should add some underwater seismic activity too? [*] I heard the Sean-Thomas can actually sense the tides with his broadband instrument. Wow. I think it would be fascinating if this data could drive my tide simulation in the aquarium. If you are willing to give it a try, I would love to write some code to do this :) Always having fun, Doug PS. Some kids never grow up ... soon I am going to break the record for the largest pile of toys :) Woo hoo! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More diamagnets From: doug doug@............. Date: Wed, 29 Sep 1999 16:36:05 -0700 You guys _had_ to show me this diamagnetism letivation stuff. Yikes. Now I'm gonna gave to add that to my toybox too. LOL -- Doug Bill wrote: > the following found on the net. thought some one might be interested...... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More diamagnets From: Karl Cunningham karlc@....... Date: Thu, 30 Sep 1999 08:28:50 -0700 Bill -- Do you have the URL from which the HTML pages were taken? I'd like to check out the rest of the site. Thanks, Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... At 10:04 PM 9/29/1999 -0500, you wrote: >the following found on the net. thought some one might be interested...... >bill NJ0X _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Mexico City Quake From: Mike Lozano mikel@....... Date: Thu, 30 Sep 1999 12:05:08 -0500 Hi gang! CNN just broke in with news of a major quake in Mexico City. They've got a helicopter in the air with pictures. Any of you guys out there got a fix on the epicentral location or magnitude? Mike Lozano Senior Meteorologist KCCI Television mikel@....... -0- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: MEXICO QUAKE From: "Francesco" franuc@...... Date: Thu, 30 Sep 1999 19:30:23 +0200 Now, it's running LQ and LR phase. M more than 6.6 Francesco I.E.S.N. Italy _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Mexico City Quake From: Oguzhan Aydogmus-HRB oaydogmus@................ Date: Thu, 30 Sep 1999 19:49:15 +0200 m:7,4 > ---------- > From: Mike Lozano[SMTP:mikel@........ > Reply To: PSN-L Mailing List > Sent: 30 Eyl=FCl 1999 Per=FEembe 20:05 > To: PSN-L Mailing List > Subject: Mexico City Quake >=20 > Hi gang! >=20 > CNN just broke in with news of a major quake in Mexico City. They've > got a helicopter in the air with pictures. Any of you guys out there > got a fix on the epicentral location or magnitude? >=20 > Mike Lozano > Senior Meteorologist > KCCI Television > mikel@....... > -0- >=20 > _____________________________________________________________________ >=20 > Public Seismic Network Mailing List (PSN-L) >=20 > To leave this list email listserver@.............. with the body of > the=20 > message: leave PSN-L >=20 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: MEXICO QUAKE From: Canie Brooks canie@........... Date: Thu, 30 Sep 1999 10:41:22 -0700 NEIC posted as 7.5Ms 99/09/30 16:31:13 16.15N 96.71W 33.0 7.5Ms A OAXACA, MEXICO Canie At 07:30 PM 9/30/99 +0200, you wrote: >Now, it's running LQ and LR phase. > >M more than 6.6 > >Francesco I.E.S.N. Italy > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: Mexico City Quake From: "Francesco" franuc@...... Date: Thu, 30 Sep 1999 19:44:48 +0200 OK. With a best analisys of the traces with winquake , Ms 7.1 or more. Later, we will post the files. Francesco _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Mexico City Quake From: "John Krempasky" johnk@....... Date: Thu, 30 Sep 1999 13:51:01 -0400 -----Original Message----- From: Mike Lozano To: PSN-L Mailing List Date: Thursday, September 30, 1999 12:58 PM Subject: Mexico City Quake >Hi gang! > >CNN just broke in with news of a major quake in Mexico City. They've >got a helicopter in the air with pictures. Any of you guys out there >got a fix on the epicentral location or magnitude? NEIC has 7.6 Ms in Southern Oaxaca. Actually a pretty good distance away from Mexico City. Worst damage is going to be in obscure places without a permanent international media presence so at least initially the damage won't seem that bad. Until people get to Oaxaca. Appears to be just onshore so at least there won't be much chance of a tsunami. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: MEXICO QUAKE From: TORBEN THAMS tobythams@................ Date: Thu, 30 Sep 1999 11:18:17 +0100 P-Wave arrived at my station at 16:42:32 UTC I have a new (experimental) setup, and this is the first quake I have registered. I am in Southern California at N 33 degrees 53.94 min W 117 degrees 56.14 min Toby Thams _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: More diamagnetism: Material sources, papers, AC diamagnetism (for Karl) From: "Charles R. Patton" charles.r.patton@........ Date: Thu, 30 Sep 1999 20:57:34 -0700 What a wonderful information hunt! Almost as good as Myst! Anyway, material sources. Belmont Equipment Co. Western Office & Warehouse 743 Dunn Way Placentia, CA 92670-6884 is a source of EDM carbon. They carry graphite from Union POCO, Ameri-Graph, Airco, UCAR (Union Carbide) and Great Lakes. I borrowed a manual for POCO Graphite, Inc., a Unocal Co., in Decatur, Texas, -- yes it is a division of the Unocal oil company. The manual explains how the stuff is made. They start with calcined petroleum coke (amorphous carbon.) The coke is then milled to various particle sizes and mixed with coal tar pitch. This mixture is then pressed or extruded into billets. The billets are baked in an oxygen-free atmosphere to drive off the volatiles from the pitch. The result is an amorphous carbon product, which is held together with carbonaceous pitch residue. This carbon is transformed to graphite (graphitized) by further heat treating at extremely high temperatures. Belmont cuts it up and can machine to order for use by the tool and die customer. My friend indicated to me that he allocates about $4 / cu.in for the graphite cost. Just for comparison, the costs from McMaster-Carr (who are not the cheapest, but certainly one of the easier companies to deal with for small, odd lot quantities) is shown below. They can be accessed on the web at: http://www.mcmaster.com/ $0.448/cu.in (5.3 cu.in / $2.38 for =BE=94 dia. x 12=94 long copper co= ated welding rods) $0.853/cu.in (72 cu.in / $61.43 for 6 x 12 x 1 carbon arc welding plates) Based on this, I=92m ordering a couple of =BE=94 welding rods. Best bang= for the buck, if they work. But it will be awhile before the results are in. I know the =BC=94 rods I have are diamagnetic, so I=92m encouraged. = (I tried one local welding store for carbon rods. They would only sell in box quantities of 50, which for 3/16 was about $15, but they didn=92t hav= e =BE and I=92m not interested in about $100 worth of carbon rods, so I passed.) Diamagnetic properties: I found some interesting tables for values of magnetic properties, including diamagnetic properties, of various substances: goto: http://www.backto-newton.com/backtonewton/magnetism.html and then click on Table I, II, and III where a R.J. Hengstebeck has listed quite a few substances in conjunction with a dissertation on a new theory of magnetism. As to the rest of his magnetic theory, I am not a physicist, so I=92m totally unqualified to comment. Perhaps someon= e else might want to. At: http://enpc1644.eas.asu.edu/Carbon/elemagpr.htm is a table indicating that diamond and graphite should be almost identical in diamagnetic performance. (For those of you with a lot of loose cash lying about!) At: http://curricula.mit.edu/6.013/chapter9/9.4.html is part of a course (?) on magnetism with a table containing diamagnetic and magnetic values. And for Karl at: http://curricula.mit.edu/6.013/chapter9/9.5.html which is the next page of the previous course, a discussion of AC diamagnetism (they call =94Artificial Diamagnetism=94) caused by conducti= ve spheres. You can equivalently think of shorted turns as rejecting a magnetic field, and thereby equivalently say the slug is diamagnetic. So use whatever analogy is most convenient, you=92re right too! Well that=92s probably a lot more than you ever wanted to know about the subject, but enjoy. Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More diamagnets From: "bill" nj0x@............ Date: Thu, 30 Sep 1999 23:15:46 -0500 I went to infoseek search and typed in diamagnets and it came back with bunches of sites. wasn't much more than what i sent. there are some other ones that look interesting. sorry I didn't make note of the html. bill -----Original Message----- From: Karl Cunningham To: PSN-L Mailing List Date: Thursday, September 30, 1999 10:29 AM Subject: Re: More diamagnets >Bill -- > >Do you have the URL from which the HTML pages were taken? I'd like to >check out the rest of the site. > >Thanks, > >Karl Cunningham >La Mesa, CA. >PSN station #40 >karlc@....... > >At 10:04 PM 9/29/1999 -0500, you wrote: >>the following found on the net. thought some one might be interested...... >>bill NJ0X > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: More diamagnetism From: meredithlamb@.............. Date: 30 Sep 1999 22:36:44 -0700 Charles Patton, WoW! You hauled in some very good material to ponder over. I have to say I don't understand it all. I hear this "POCO" graphite seems to have unique properties, but as yet, exactly what it is I don't know. How it racks up to "standard" graphite is a unknown. I've also read there is some 12 million combinations of carbon with the other elements. Maybe their manufacturing process somehow differs from the others? From my expeditions to surplus outlets, its kind of a gamble on whether the stuff you get is diamagnetic or not. Anymore, I take along a nice thick piece of neodymium for testing on the spot. If its a piece of DC motor commutator brush, I hold the cable end lightly, and see the reaction of the carbon/graphite fairly well. Carbon rods can be tested simarily by lightly holding the end, or a short length of scotch tape can help. Have run into pieces where one end is paramagnetic, and the other end is diamagnetic. One never knows. Likewise, I've seen same carbon manufacturers, but their products can have varying responses, from one piece to the next. I used to think it was the manufacturer, but, anymore, one has to also consider the possibility of the material being somehow subjected to varying elements, and internal variance factors that make or break; the ideal diamagnetism. Speculation.... Its doesn't seem like their is any guarantee whatsoever, on what one gets, from any source. Another factor I had misconceptions on: The color of the graphite tells very little about its diamagnetism...test them all, whether very black, or grayish black. Thanks for the huge effort. I especially like the tables, as my nearest library doesn't have such. Thanks, Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More diamagnetism: Material sources, papers, AC diamagnetism (for Karl) From: offutt@............ (Warren Offutt) Date: Fri, 1 Oct 1999 04:05:58 -0600 (MDT) Charles Patton's post rang a bell: At the New York World's Fair, 1939-1940, I recall seeing discs of aluminum (several inches in diameter) levitated several inches above an AC powered magnet. It seems to me I recall seeing this described in popular science magazines of the 1950s as well. A long time ago, and memory is fallible, but I think it is correct. warren _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Diamagnetism; Magnetic Suspension From: "Mark Robinson" other@............... Date: Fri, 1 Oct 1999 22:39:48 +1200 Gentlepersons , I have seen a thing made here in New Zealand which hangs an object beneath an energised pole piece. the abject had a piece of what llooked like ferrite in it, and I assumed that the pole piece was was energised with a high frequency, and further that the suspension relied on hysteresis to provide the stable position which was about 25mm below the energised pole piece. The suspended object was a globe weighing a couple of hundred grams. I tried to find the manufacturers, or any reference on the web, but no luck. If I do, I will post further regards Mark _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Levitating objects From: meredithlamb@.............. Date: 1 Oct 1999 07:25:26 -0700 Hi Warren, Perhaps (?), what you saw at the 1939 Worlds fair, was akin to this web site. They are trying to commerilize their display projucts. See: http://www.teslev.com/teslev/morephot.html which is part of: http://www.teslev.com/teslev/levinfo.html I note the netherlands web site seems to have more pictures than previous. It also makes reference to the above, and Martin Simons commercial unit for sale: http://www-hfml.scikun.nl/hfml/levitate.html Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Levitating objects (correction) From: meredithlamb@.............. Date: 1 Oct 1999 08:12:55 -0700 Warren and all, I see my references hit the not found computer wall. Try: http://www-nwi.sci.kun.nl/index-eng.html then, go to organization, click physics, then, scroll down to Research Departments. See, the Experimental solid state physics I (and) specifically click "High Field Magnet Laboratory". Then click, "Some (serious) fun in high magnet fields". Then look for "levitating displays", and click that. At the bottom of this page, is a clickable reference to "more photos". All these "displays" use some energy, but specifics are not spelled out, as its a commercial firm still in R&D, as they claim. Long route to go, but it should get you there. Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More diamagnetism: Material sources, papers, AC diamagnetism (for From: Doug Crice dcrice@............ Date: Sat, 02 Oct 1999 05:31:38 -0700 The levitating aluminum plate is a different phenomena. You put the plate over an AC-powered electromagnet and the varying magnetic field induces eddy currents in the plate. The eddy currents flowing in the aluminum create another magnet with the same polarity which causes the aluminum plate to be repelled by the electromagnet. Of course it only works with an AC field. Doc Edgerton, who you might know as the inventor of the strobe light, made an underwater seismic energy source called a "boomer" which had a metal plate snugged up against a coil. He would charge up a capacitor (to several joules) and then dump the charge into the coil. The large current in the coil induced eddy currents in the metal plate which made it bend away from the coil, push against the water, and make a pretty good pop in the ocean. The boomer was a relatively high-frequency seismic source and is still used for shallow, high-resolution seismic reflection surveys. He made another seismic energy source which ran on the same power supply called a sparker. A few thousand volts from a capacitor is discharged into an electrode trailing behind the boat. The discharge would vaporize the salt water creating a small explosion and of course seismic energy. The sparker was lower frequency than the boomer and is used for deeper (hundreds of meters) surveys. Doug Crice Warren Offutt wrote: > > Charles Patton's post rang a bell: At the New York World's Fair, > 1939-1940, I recall seeing discs of aluminum (several inches in diameter) > levitated several inches above an AC powered magnet. > > It seems to me I recall seeing this described in popular science magazines > of the 1950s as well. > > A long time ago, and memory is fallible, but I think it is correct. > > warren > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Doug Crice web site http://www.georadar.com GeoRadar Inc. e-mail dcrice@............ 19623 Via Escuela Drive phone 408-867-3792 Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: HS-10-1 From: Arie Verveer ajbv@............ Date: Sun, 03 Oct 1999 13:40:50 +0800 Hi, I've just set up one of the group buys (Hs-10-1) geophones. All seems to be working well. But I was wondering, what is the range on the period adjustment screw? It appears to have some unlabeled scale. Any help on the range and the best way to set the device to 1 Hz ? I hope to achieve some better response to distance quakes with this Z axis device. The channel designation : ..au1 East-West high frequency ..au2 Geospace HS-10-1 Z axis (This replaced E-W low frequency) ..au3 N-S high frequency ..au4 N-S Low frequency Regards Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: HS-10-1 From: S-T Morrissey sean@........... Date: Sun, 3 Oct 1999 13:54:40 -0500 (CDT) Arie, The period and the mass centering of the HS-10-1 are both accomplished by adjusting the same part. The HS-10s that I have were originally encased in deep borehole pressure cases, so they have no dials or indicators. Some versions have a screw adjustment for the position (and so the strength) of the calibrator magnet. For adjustments, there is a rod protruding from the case inside the calibrator assembly (which may not be complete). The rod, about 1/8" dia, has an approx. 3/8" dia threaded bushing attached to it with a setscrew (or two). The threads of the bushing are engaged by the astitizing spring that controls the period. The upper (in Z) end of the rod may have the calibration coil installed, with fine coilly leads running to the terminal strip. There is a three-mark index or scale marked in the inside of the cut-aways in the cylinder of the calibrator housing. The lower end of the white nylon cal coil assembly should be aligned with the middle mark to center the mass. To adjust the centering, loosen the setscrews on the threaded bushing and move it appropriately. The mass position may change as the screws are tightened. The period is adjusted by changing the length of the small spring, which is done by rotating the threaded bushing to engage or release PART of A TURN of the spring. I make a mark on the 1/8" shaft to indicate the position for centering before I loosen it to rotate it. Naturally the adjustments interact. Sometimes the mass position will have to be raised slightly to get 1 second; slightly tilt the seis to test this. I have been able to get periods from 0.8 to 1.1 seconds. I use a function generator, a frequency/period counter, and an oscilloscope to set the period. The generator drives the calibration coil (or a bridge with the main coil), and one axis (time) of the oscilloscope, which is operated in X_Y mode. THe seis signal coil connects to the other axis. Usually the normal input is used for the signal because it has more gain or sensitivity. The function generator is adjusted for a flat-line lissajous (sp?) display, and a period (frequency) counter on the function generator indicates the seismometer period. THis method can be accurate to a millisecond, especially if you can finely adjust the function generator to see the elipse pattern collapse to a line and then reverse. In liew of the test equipment, look at the amplified signal and measure the length of time for ten oscillations with a stopwatch. The adjustment of the period is really not that critical, and +,- 5% is probably adequate for a critically damped sensor. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Levitation notes From: meredithlamb@.............. Date: 3 Oct 1999 15:56:23 -0700 Hi all, Just made another stand for levitation of magnets. Have noted several items that maybe of interest. Am using carbon brushes. Four rectangular straight side carbons per the bottom plate and 4 per the top carbon plate. The carbon mounting surfaces are fiberboard, rectangular pieces. I didn't note any differece with the slight areas "open" to exposure. The neodymium magnet I used is a "wing" shape, about 9/16" long, 7/16" wide and 1/8" thick. The weight is about 2/10's ounce. Initial floating attempts, all yielded no better than a point on the magnet making contact somewhere on the carbon. I then introduced a rectangular magnet to the side of the floating magnet, and this seemed to worsen or correct the magnet angle. The distance of the rectangular magnet is about 7" away; but it will wildly vary with different setups. Of course, now it floats. Maybe this could be called a bias/correction magnetic field. One will have to maneuver such around the area of their own setup. Unlike a round disk magnet, these wing shapes, are not directly centered under the vertical magnet above. Its not much, but its there, at least from this first attempt. The "bias magnet" angle, seems to control the alignment of the floating magnet. They both have the same angle. This suggests a means of control of length direction, if desired. The height adjustments of the ferrite donut magnet are much more sensitive in adjustment than with a very small disk magnet (Radio Shack cat. no. 64-1895). I'am guessing this wing magnet is at least 20 times the weight of the Radio Shack magnet. Along with the heavier weight, the vertical oscillation period of the wing magnet is noticeably longer, perhaps between 1-2 seconds. Fun when it works, frustration when it doesn't. Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Levitation notes From: JIm Hannon jmhannon@........ Date: Sun, 03 Oct 1999 18:05:21 -0500 meredithlamb@.............. wrote: > Hi all, > > Just made another stand for levitation of magnets. > Have noted several items that maybe of interest. > > Am using carbon brushes. Four rectangular straight > side carbons per the bottom plate and 4 per the > top carbon plate. The carbon mounting surfaces > are fiberboard, rectangular pieces. I didn't note > any differece with the slight areas "open" to > exposure. > > The neodymium magnet I used is a "wing" shape, > about 9/16" long, 7/16" wide and 1/8" thick. The > weight is about 2/10's ounce. > > Initial floating attempts, all yielded no better > than a point on the magnet making contact > somewhere on the carbon. I then introduced a > rectangular magnet to the side of the floating > magnet, and this seemed to worsen or correct > the magnet angle. The distance of the rectangular > magnet is about 7" away; but it will wildly vary > with different setups. Of course, now it floats. > Maybe this could be called a bias/correction > magnetic field. One will have to maneuver such > around the area of their own setup. > > Unlike a round disk magnet, these wing shapes, > are not directly centered under the vertical > magnet above. Its not much, but its there, at > least from this first attempt. > > The "bias magnet" angle, seems to control the > alignment of the floating magnet. They both > have the same angle. This suggests a means of > control of length direction, if desired. > > The height adjustments of the ferrite donut > magnet are much more sensitive in adjustment > than with a very small disk magnet (Radio Shack > cat. no. 64-1895). I'am guessing this wing > magnet is at least 20 times the weight of the > Radio Shack magnet. > > Along with the heavier weight, the vertical > oscillation period of the wing magnet is > noticeably longer, perhaps between 1-2 seconds. > > Fun when it works, frustration when it doesn't. > > Meredith Lamb > Meredith, Those "wing" shaped magnets probably came from harddrive voice coil actuators. "Some" of them have both a north and south pole on each side rather than just a north pole one one side and a south pole on the other. This could explain your tipping problem. -- Jim Hannon http://soli.inav.net~jmhannon/ 42,11.90N,91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Levitation notes From: meredithlamb@.............. Date: 3 Oct 1999 16:34:23 -0700 On Sun, 03 October 1999, JIm Hannon wrote: > > Meredith, > Those "wing" shaped magnets probably came from harddrive voice coil > actuators. "Some" of them have both a north and south pole on each side > rather than just a north pole one one side and a south pole on the other. > This could explain your tipping problem. > > -- > Jim Hannon > http://soli.inav.net~jmhannon/ > 42,11.90N,91,39.26W > WB0TXL Hi Jim, No, these magnets are the normal 2 pole types. However they are from such, but, of the older type...i.e., 4 normal 2 pole magnets per assembly. Newer ones were 4 pole, with either one magnet per assembly, and rarer, 2 such magnets per assembly. Interesting note, somewhere in my internet travels, one site mentioned that some of the early (~1972)"super magnets", were a composite of platinum and another/more ingredients. Likely they were very limited in production. I would agree; a 4 pole would have alot of problems floating...ha. I noted the same tipping effect on my first levitation stand also, but didn't pursue it, at the time. Thanks, Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: HS-10-1 From: Larry Cochrane cochrane@.............. Date: Sun, 03 Oct 1999 23:27:43 -0700 Hi Arie, At 01:40 PM 10/3/99 +0800, you wrote: >Hi, I've just set up one of the group buys (Hs-10-1) geophones. All seems >to be working well. But I was wondering, what is the range on the period >adjustment >screw? It appears to have some unlabeled scale. Any help on the range and the >best >way to set the device to 1 Hz ? Please see S-T Morrissey response. I didn't even know it had a period adjustment until your message! After reading your email message I took a closer look at the sensor. I took it offline to but it on the bench and I swear to god no more then 2 minutes later we had a Ml 2.8 event near by. Talk about Murphy's law....This would have been a nice event to record with my new sensor (*.lc9 files)... > >I hope to achieve some better response to distance quakes with this Z axis >device. >The channel designation : > >.au1 East-West high frequency >.au2 Geospace HS-10-1 Z axis (This replaced E-W low frequency) >.au3 N-S high frequency >.au4 N-S Low frequency Dave Nelson, should I update Arie's station information or can you do it? -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: HS-10-1 From: Arie Verveer ajbv@............ Date: Mon, 04 Oct 1999 19:21:51 +0800 Hi Sean-Thomas, Thanks for the great info on the HS-10-1. A super explanation. Regards Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Hilger and Watts seismograph? From: Doug Welch welch@................... Date: Mon, 4 Oct 1999 20:00:26 -0400 (EDT) I have just recently picked up what I believe to be a seismograph made by Hilger & Watts (SG 416). However, it has no manual and I am keen to locate documentation (or at the very least, its detection characteristics). Can anyone on this list help (or provide a good lead)? Many thanks, Doug Welch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Ricther Scale From: "David Wilson" davidbw@.......... Date: Tue, 5 Oct 1999 17:01:29 +1300 When I was young events where measures on the 'Open Ended Ricther = Scale". When was the end sealed and has this changed the calibration?
When I was young events where measures on the 'Open = Ended=20 Ricther Scale".
 
When was the end sealed and has this changed the=20 calibration?
Subject: Re: Hilger and Watts seismograph? From: Doug Crice dcrice@............ Date: Tue, 05 Oct 1999 05:22:43 -0700 A web search suggests that Hilger & Watts seems to be a manufacturer of surveying instruments. This may be a collimator which is a device to ensure that a surveying instrument is positioned over a station, sort of an optical plumb bob. Doug Welch wrote: > > I have just recently picked up what I believe to be > a seismograph made by Hilger & Watts (SG 416). However, > it has no manual and I am keen to locate documentation > (or at the very least, its detection characteristics). > Can anyone on this list help (or provide a good lead)? > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Software advice From: offutt@............ (Warren Offutt) Date: Tue, 5 Oct 1999 06:52:15 -0600 (MDT) Hello all, can anyone suggest where I can find software for shallow, short range seismic studies? Here, in the mountains of south central New Mexico, water-well drilling (typically 500 foot depth) sometimes yields expensive disappointments. I'd like to experiment with active seismic probing similar to petroleum prospecting, but much shorter range and depth, to better understand the subsurface features. Acoustic sources, sensor arrays and data acquisition all appear straightforward, but where can I find analytical software? warren _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Software advice From: Doug Crice dcrice@............ Date: Tue, 05 Oct 1999 06:21:38 -0700 Warren Offutt wrote: > can anyone suggest where I can find software for shallow, short range > seismic studies? > Typically, refraction surveys are used for ground water investigations. You should start by reading up on the method, which is described in virtually all introductory books on exploration geophysics. It's not particularly difficult to perform the calculations by hand with a pocket calculator or using graphical methods. You can read a brief description at http://www.naevageophysics.com/seismics.html A short but comprehensive booklet by Bruce Redpath is available free from Geometrics on their web site at http://www.geometrics.com/env.html Commercial software is available from Rimrock Geophysics in Lakewood, Colorado (phone 303-985-2522 if the area code hasn't changed) and Interpex at http://www.interpex.com/ Interpex has a broad range of software for exploration geophysics. Rimrock is operated by a retired USGS geophysicist. I would guess that there may be some free programs available, but I don't have a source. A properly designed and manufactured exploration seismograph is a joy to use, maybe you could line up some corporate sponsors to buy you one of the Geometrics units. There are many used systems available which are adequate for refraction surveys. Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Ricther Scale From: John Lahr lahr@................... Date: Tue, 5 Oct 1999 08:11:23 -0600 (MDT) Hi David, The end is still open. What made you think otherwise? News accounts frequently get this wrong, and say that the Richter scale runs from 0 to 10. Actually very small earthquakes have negative magnitudes. The largest recorded so far is the 9.5 Chile earthquake in 1960. JCLahr > From: "David Wilson" > When I was young events where measures on the 'Open Ended Ricther Scale". > > When was the end sealed and has this changed the calibration? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Finger list From: John Lahr lahr@................... Date: Tue, 5 Oct 1999 08:44:48 -0600 (MDT) The USGS finger list is just shows the latest 21 events. For a list covering the past two weeks, check out the CNSS and Canadian National Net experimental Combined Catalog at http://www.cnss.org/cnss.cat.html JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: Ricther Scale From: "Liberio Rossi" l.rossi@....... Date: Tue, 5 Oct 1999 17:18:22 +0200 -----Messaggio originale----- Da: John Lahr A: psn-l@.............. Data: marted=EC 5 ottobre 1999 16.23 Oggetto: Re: Ricther Scale >Hi David, > >The end is still open. What made you think otherwise? News accounts >frequently get this wrong, and say that the Richter scale runs >from 0 to 10. Actually very small earthquakes have negative magnitudes. >The largest recorded so far is the 9.5 Chile earthquake in 1960. > >JCLahr > >> From: "David Wilson" >> When I was young events where measures on the 'Open Ended Ricther Scal= e". >> >> When was the end sealed and has this changed the calibration? > >OK Lahr I agree with you that Ricther scale can be negative! >Regards Liberio Rossi l.rossi@.................................................................. ___ ________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: geophysics journal URL From: robert barns 75612.2635@.............. Date: Tue, 5 Oct 1999 14:52:07 -0400 Hi gang, From Physics Today, Oct. '99, p68: "The American Geophysical Union and the Geochemical Soc. have created a= n on-line journal dedicated to interdisciplinary research in geochemistry a= nd geophysics. One aim of "Geochemistry, Geophysics Geosystems" -or G-Cubed= for short-is to keep publication costs and subscription rates low...Anoth= er reason for going all-electronic is to enable authors to publish very larg= e data sets which paper journals could never afford to print. Access to th= e journal will be free at least the first year. The first issue is set to = be posted on the journal's Web site www.g-cubed.org in early Dec., prior to the AGU's fall meeting and the journal will be updated weekly." Another URL I have found useful is joe.mehaffey.com This contains an enormous amount of info on GPS. There is an informative= discussion on GPS timing in the Information Section dated 18 Apr. '99. I bought a digital wrist watch (Zeit, $110 incl. shipping) about 3 week= s ago which uses timing signals from WWVB (60 kHz) in Colorado. It works perfectly here in NJ (but I don't like digital watches). It has= not been off WWV by more than 0.5 sec. (the limit of checking) and it skipped Sept. 31 like it should. I can hardly believe that it can reciev= e a sig. at 60kHz (wave length about 3 miles) but it does. See this at = www.topixgallery.com Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hilger and Watts seismograph From: John Taber taber@............. Date: Wed, 6 Oct 1999 09:28:00 +1300 (NZDT) Doug, I have a Hilger and Watts manual for the SG450 (Wilmore MKII). From earlier discussions with Dave Nelson, there are some similarities between the SG416 and SG450, so if no one has an SG416 manual I can send you a copy of mine. Cheers, John Taber _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hilger and Watts seismograph From: meredithlamb@.............. Date: 5 Oct 1999 14:46:28 -0700 On Tue, 05 October 1999, John Taber wrote: > > Doug, > > I have a Hilger and Watts manual for the SG450 (Wilmore MKII). From > earlier discussions with Dave Nelson, there are some similarities > between the SG416 and SG450, so if no one has an SG416 manual I can > send you a copy of mine. > > Cheers, > > John Taber John Taber, Is the suspension system on the seismo like a Wood-Anderson, with its mass on a taut wire?? Kind of a british variety? Am vaugely guessing? Thanks, Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Charles Patton levitation suggestion... From: meredithlamb@.............. Date: 5 Oct 1999 15:52:53 -0700 Hey Charles, Your idea of using rods set flat side by side on a board (actually 2 boards), for carbon levitation does work. I got a number of .242" diameter carbon rods, and tried it with wide 2 pole (normal) neodymium magnets. One was a "wing" shape, and another with 5 points, and they both worked. I used eight side by side, but it would have worked with less...depending on the width/length of the neo floated. Afew very interesting effects showed up right away with this type of surface: One; when disturbed it wasn't unusual for the floating neo to bang against the top and bottom of the carbon/rod sandwich, they seemed to have wider range in other words. Probably not surprising for the undulating surface instead of a flat surface. Two; both of this neo magnets floated without the aid of additional "bias magnets", to offset dragging tilts. They weren't perfect but no point touched the carbon. Regardless, I used acouple magnets on either side, which helped correct tilts from the horizontal, and sometimes they acted to assist centering between the carbon layers. It was definately easier to float neodymium magnets overall. I even floated the little Radio Shack Cat No. 64-1895 neo disk quite easily over these rods. There may be explanations, I think the rods were more diamagnetic than my smooth surface carbon brushes. The rods were laid out where from the end view, the rods sat vertically aligned atop each other (not like a rod nestled in the valley of the opposing rods/carbons/plate). ....................................... Sometimes, I think a old but very large meter movement, with its torsion spring, could provide somewhat of a "scale" with diamagnetics? One might have to remove the meter magnet and mount something like the tiny radio Shack magnet on the end of the pointer? Speculating. ........................ Another minor side note, I used my string /beam balance to note the repulsion diamagnetics in my hand coming close. Water is diamagnetic. Thanks for the rod side by side suggestion, Meredith Lamb I would expect some limit on rod size v/s neo floated; but thats the only size I have. Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Charles Patton levitation suggestion... From: "Charles R. Patton" patton@.......... Date: Tue, 05 Oct 1999 17:13:20 -0700 Great Meredith! I appreciate the feedback. How long were the rod pcs you used? My own luck with the EDM carbon is mixed so far. The big hunk I was given attracts the magnet -- not so good for this experiment. But two =BE" sq. by 1" act just fine =96 they=92re just not big enough for an experiment. = I need to go back to the mold maker and see if he thinks he gave me some impregnated carbon. Still haven=92t ordered the carbon rods from McMaster-Carr. Maybe tomorrow. I=91ve also tried to get some bismuth from a metal dealer, but he hasn=92t called back. I have a couple more names to try. I=92m concerned about getting bismuth shot from Precision Reloading as the purity/composition is an unknown. Regards, Charles R. Patton charles.r.patton@........ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Meeting of Educational networks at AGU? From: Larry Cochrane cochrane@.............. Date: Tue, 05 Oct 1999 18:14:17 -0700 Hi Robert, At 05:55 PM 10/4/99 -0400, Bob Phinney wrote: >I need to convene a meeting of people who operate educational >networks, both the PEPP crowd and other groups. AGU Sunday for >half a day is the best time. > >However, I fear that people are already ultrascheduled for that period. >Are you available? I should be able to make it, but I don't want to have to pay over $100.00 to get into the AGU. Will this meeting be part of the AGU meeting or will/can we have it somewhere else? > >Ed and Larry(s) , we haven't chatted in a long time, and >much has changed in the PEPP situation. I am hoping to decentralize >the relationship between PEPP and the university-sponsored networks, but >set up some technical coordination to simplify the work of starting and >operating stations. I have a draft plan, but first, we need to >try to grab an AGU time slot, if it's possible. I'm not sure if Edward will be coming out to the AGU this time. The last time I talked to him he wasn't sure if he was going to the meeting. He would have to pay out of his own pocket since he is not presenting anything this time. Another possibility for a meeting is with Lind Gee at Berkeley. We have been talking about having a PSN meeting at the Berkeley Seismo Lab sometime around AGU. Yesterday I had a meeting with Lind, Catherine Johnson and two men (sorry I don't remember their names) from IRIS. I was there to talk about PSN helping out setting up some sensors in schools around here. We did talk a little about the PSN meeting. It was suggested that maybe IRIS people could also attend. Maybe you and other PEPP people could also be there? Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: HS-10-1 From: Larry Cochrane cochrane@.............. Date: Tue, 05 Oct 1999 19:10:35 -0700 Sean-Thomas, Thanks for the info. I'm not sure if these sensors have a calibration coil. If they did would there be another set of wires coming out of the sensor? The sensor we got only have 2 wires, some have three but the third is only a ground wire. There is no resistance between the ground wire and the other two wires. Is it possible that you need to open up the sensor to gain access to the calibration coil? Can you elaborate on how you can test the period using a bridge and the main coil? Do you use three resistor with the same resistance as the coil and place the coil as the forth leg of the bridge? One more thing. Do you know what loading resistor is used for critical damping if the main coil resistance is around 400 ohms. GeoSpace's web page does not have this information. Again, thanks for all of your help. Regards, Larry Cochrane Redwood City, PSN At 01:54 PM 10/3/99 -0500, you wrote: >Arie, > >The period and the mass centering of the HS-10-1 are both accomplished >by adjusting the same part. The HS-10s that I have were originally >encased in deep borehole pressure cases, so they have no dials or >indicators. Some versions have a screw adjustment for the position >(and so the strength) of the calibrator magnet. > >For adjustments, there is a rod protruding from the case inside >the calibrator assembly (which may not be complete). The rod, about >1/8" dia, has an approx. 3/8" dia threaded bushing attached to it >with a setscrew (or two). The threads of the bushing are engaged by >the astitizing spring that controls the period. The upper (in Z) end >of the rod may have the calibration coil installed, with fine coilly >leads running to the terminal strip. > >There is a three-mark index or scale marked in the inside of the >cut-aways in the cylinder of the calibrator housing. The lower end >of the white nylon cal coil assembly should be aligned with the middle >mark to center the mass. To adjust the centering, loosen the setscrews >on the threaded bushing and move it appropriately. The mass position >may change as the screws are tightened. > >The period is adjusted by changing the length of the small spring, which >is done by rotating the threaded bushing to engage or release PART of >A TURN of the spring. I make a mark on the 1/8" shaft to indicate the >position for centering before I loosen it to rotate it. Naturally the >adjustments interact. Sometimes the mass position will have to be >raised slightly to get 1 second; slightly tilt the seis to test this. >I have been able to get periods from 0.8 to 1.1 seconds. > >I use a function generator, a frequency/period counter, and an oscilloscope >to set the period. The generator drives the calibration coil (or a bridge >with the main coil), and one axis (time) of the oscilloscope, which is operated >in X_Y mode. THe seis signal coil connects to the other axis. Usually >the normal input is used for the signal because it has more gain or >sensitivity. The function generator is adjusted for a flat-line lissajous (sp?) >display, and a period (frequency) counter on the function generator >indicates the seismometer period. THis method can be accurate to >a millisecond, especially if you can finely adjust the function generator >to see the elipse pattern collapse to a line and then reverse. > >In liew of the test equipment, look at the amplified signal and measure >the length of time for ten oscillations with a stopwatch. > >The adjustment of the period is really not that critical, and +,- 5% >is probably adequate for a critically damped sensor. > >Regards, >Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Charles Patton levitation suggestion... From: The Lahrs JohnJan@........ Date: Tue, 05 Oct 1999 20:38:22 -0600 At 05:13 PM 10/5/99 -0700, Charles Patton wrote: > I’m concerned about getting bismuth shot from Precision >Reloading as the purity/composition is an unknown. I'll second that concern. The shot that I melted is less effective than the carbon. John John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 http://lahr.org/john-jan I am only one, But still I am one. I cannot do everything, and because I cannot do everything, I will not refuse to do the something that I can do. Edward Everette Hale _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: HS-10-1 From: S-T Morrissey sean@........... Date: Tue, 5 Oct 1999 22:45:02 -0500 (CDT) Larry, Unfortunately I am unfamiliar with the various configurations of the HS-10-1. I would assume that the period adjusting spring is part of the design of all the sensors, even without a calibration coil. I have a file at the U. that might have more info. For calibration with a bridge in the signal coil/amplifier circuit, a simple resistive bridge is sufficient. I designed one into the remote calibrator for the remote telemetry stations using the L4-C; most did not have cal coils because the USGS tried to save $$; or the coils were burned out (a 1.5 V battery will do it). The bridge is in the conventional shape of a diamond; the upper right resistor being the seismometer AND its' parallel damping resistor; for starters this could be about twice the coil resistance (I can repeat the info on determining the damping R if you need it). So in your case, the seis is 400 ohms, damped by 800 ohms, for a net value of (400*800)/(400+800)=267 ohms. The resistor at the upper left has to match this to balance the bridge. So I would install a 500 ohm 10-turn potentiometer. The lower two bridge Rs should be about 100 times the seis R, so I would use 27k (1%) ohms. This high value helps limit the calibration current and isolates the amplifier. Match the 27ks with a meter if necessary. Now consider the bridge as a baseball park, with home plate at the bottom, 1st base is at the right, 2nd at top, etc. The seismometer is connected from 1st to 2nd, with 1st being the common or ground connection. The amplifier is connected between 3rd and 1st, again with 1st being ground. The signal generator must have a floating output (use large capacitors from the ground side if it does not), and is connected thru a large (1 meg ohm) pot to home plate and 2nd base. It does not take much current to drive the seismometer with the signal coil. To balance the bridge, clamp the seis by laying it on its side (some seises, like the L4-C, totally short out in some horizontal positions). Look at the amplifier output (scope, meter, digitizer), and with a handy sine wave like 1 to 10 hz, adjust the balance pot (between 2nd and 3rd) for a minimum output. Keep the voltage low so the amplifier isn't saturated. What this does is to make the currents in each side of the bridge equal: half the current flows from home to 2nd via 1st, and the other half via 3rd. If the 27k resistors are equal, the voltage drop across them will be equal, and none of the calibration DRIVE signal will be seen by the amplifier. However, it IS flowing through the seis signal coil, so when the seis is set upright (unclamped), the voltage produced by the motion of the mass will be present at the amplifier via the balance pot from 2nd to 3rd, which is relatively small (270 ohms) compared to the amplifier input R of 10k to 100k ohms. For some seismometers with large inductances, a capacitor needs to be placed across the balance pot; it needs the same reactance as the seis inductance at the average calibration frequency. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Charles Patton levitation suggestion... From: meredithlamb@.............. Date: 5 Oct 1999 22:08:06 -0700 On Tue, 05 October 1999, "Charles R. Patton" wrote: > > Great Meredith! > I appreciate the feedback. How long were the rod pcs you used? I way overdid it....I used 6" long pieces, with 8 laid side by side. I'am pretty sure one doesn't need much more than say....1/4", over the diameter of the neo being levitated. Your two diamagnetic pieces would easily float the dinky Radio Shack neo, and probably up to 1/2" diameter disk, is my guess. For such a small deal you will need spacers to separate the carbons, or, mount them on wood/plastic whatever thats not magnetic. I glued mine on fiberboard and use corner bolts/nuts to adjust the distance. I'am kind of trying all sizes in that assembly, so, I'am not too restricted on magnets diameter (2" X 6"). The big problems arise with thick stuff, and their lower surface repulsion/area effects...their is a limit on weight I'am afraid. I've got up to 3/10s ounce fairly easily, but, my chunkiest neo, with a weight of 1 & 3/4 ounce, just can't quite float free....1/2" thick, but little surface area. Hmmmmm, maybe I should put steel disks on the ends to increase the surface area, if I can find something, sometime; guess its worth a try. If you get the RS pill neo, the distance doesn't seem to be too critical; measure the neo, and put a equal thickness on each side, it should pop and float readily. I've seen the RS neo float with up to 4 thicknesses on each side, it really depends on the overhead ferrite magnet and of course your carbon. I can't speculate on bismuth, I've not tried that yet. I've heard some say its better, and others not as good. Perhaps the point with bismuth is that one can make any size, and have it work to some degree right off the bat; whereas, carbon is a real shot in the dark in comparison. If one just wants to float something, the success would seem to be on the bismuth side overall. Regardless of source, I've yet to hear anyone tell of total failure with bismuth, whether it be shotgun shell load or whatever. The ultra pure stuff seems to be out of reach price wise. I'am not even sure that the ultra pure stuff is that much better than shotgun shell load? As the size of the floating neo increases in thickness, less space is available (with my carbon that is), and often I can only float it with about .015" spacing each side of the neo. The carbon rods improved that here, it looks like about .025" or so each side. I wonder what a super grade carbon would do? When I get ready to shove my assemblys under the ferrite, I cup my hand over the nearest to the magnet side, otherwise the neo can rocket up to the ferrite. The mystery continues.... Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Software From: offutt@............ (Warren Offutt) Date: Wed, 6 Oct 1999 08:54:06 -0600 (MDT) Can anyone help on the following search for info? The Sept 98 edition of Explorer (Pub of American Assoc of Petroleum Geologists) noted that Chris Liner had some public domain software for 3-d analysis. However, the URL at AAPG apparently took it off their web site at end of 1998 or so ... Can anyone suggest how to contact Chris Liner and/or locate a copy of this software? Any tips or leads greatly appreciated .... Regards, warren _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Software From: "Mark Robinson" other@............... Date: Thu, 7 Oct 1999 04:42:51 +1300 http://douze.utulsa.edu/~cll/ChrisLiner.html > Can anyone help on the following search for info? > > The Sept 98 edition of Explorer (Pub of American Assoc of > Petroleum Geologists) noted that Chris Liner had some > public domain software for 3-d analysis. However, the > URL at AAPG apparently took it off their web site at > end of 1998 or so ... > > Can anyone suggest how to contact Chris Liner and/or locate > a copy of this software? > > Any tips or leads greatly appreciated .... > > Regards, > warren > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hilger and Watts seismograph From: John Taber taber@............. Date: Thu, 7 Oct 1999 16:18:08 +1300 (NZDT) Meredith, I'm not familiar with the Wood-Anderson suspension, but the Wilmore uses leaf springs for the mass. You can get some idea from the picture I've scanned in at http://www.quaketrackers.ac.nz/Testdir/wilmore.html John Meredith Lamb wrote: > >Is the suspension system on the seismo like a >Wood-Anderson, with its mass on a taut wire?? >Kind of a british variety? Am vaugely guessing? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Charles Patton levitation suggestion... From: George Harris gjharris@............. Date: Wed, 06 Oct 1999 16:02:21 -0400 Regarding materials with negative susceptibilities: Perhaps I have missed something along the way, but there are a number of materials with higher negattive susceptibilities than carbon. The handbook of Chemistry and Physics (59 th edition - 1979) lists the following: Carbon or diamond -6 Bismuth (solid) -280 Aluminum Sulfate (anhydrous) -93 Aluminum Sulfate Hydrate (Al2(So4)3.18H2O -323 Calcium Carbonate -38 Ammonium Nitrate -34 Ammonium Sulfate -67 The values stated are per gram, so the specific gravities are probably important also. It would seem that the crystal form should be the best if available. Have any of these been tried? George Harris _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hilger and Watts seismograph From: Karl Cunningham karlc@....... Date: Wed, 06 Oct 1999 22:28:00 -0700 John -- Very interesting picture. Do you have the legend? I'm curious what some of the numbers are pointing to. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... At 04:18 PM 10/7/99 +1300, you wrote: >Meredith, > >I'm not familiar with the Wood-Anderson suspension, but the Wilmore >uses leaf springs for the mass. You can get some idea from the picture >I've scanned in at >http://www.quaketrackers.ac.nz/Testdir/wilmore.html _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Forward: Science Fair From: Larry Cochrane cochrane@.............. Date: Thu, 07 Oct 1999 01:33:06 -0700 All, I received this today. Can anyone help Stuart. Please respond to him directly since he is not on the list. -Larry >From: ERICHHC@....... >Date: Wed, 6 Oct 1999 22:23:27 EDT >Subject: Science Fair PLEASE READ >To: cochrane@.............. >X-Mailer: AOL 4.0 for Windows 95 sub 27 > >To whomever could be of help, > >I am in 9th grade and doing an experiment on earthquakes. I need help with >the seismology section of my report. I am doing an experiment to determine if >it is possible to tell from a home made seismograph from which direction the >force of an earthquake originates. I am having difficulty in doing the >experiment and trying to create both the variables and the controls for my >study. Could anyone in this department be of help in my study to give me >some direction of how to accomplish this experiment. > >Thank you, > >Stuart Bern > >MESTUWHORU@....... > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Forward: Science Fair From: John Lahr lahr@................... Date: Thu, 7 Oct 1999 08:22:43 -0600 (MDT) Dear Stuart, In order to determine the direction from a seismic station to an earthquake, three seismometers need to be run at the seismic station. One for up/down (vertical) motion, one for east/west (horizontal) motion and one for north/south (horizontal) motion. This is a tall order indeed! You might want to consider building the table-top seismology demonstration that is described here: http://lahr.org/john-jan/TableTop/index.html This setup uses a single vertical seismometer, so you will not be able to investigate the direction the waves are traveling. However you could experiment with the effect of friction on the size and frequency of earthquakes. Hope this helps a bit. Cheers, JCLahr ################################## John C. Lahr ################################# Seismologist ################################ U.S. Geological Survey ############################### Geologic Hazards Team, MS966 ############################## PO Box 25046 #############################/############################## ############################/############################### Denver, Colorado 80225-0046 ################################ Phone: (303) 273-8596 ################################## Fax: (303) 273-8600 ################################### lahr@........ ##################################### http://giseis.alaska.edu/lahr http://lahr.org/john-jan _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Forward: Science Fair From: GeE777@....... Date: Thu, 7 Oct 1999 11:39:33 EDT Hello, I invented a 3 component geophone and an apparatus to plant this geophone in shallow holes. It also helps align and level the geophone using a compass and level on the handle of the planting tool. (US patent no. 5,007,031 Granted on April 9,1991) I liked the idea of planting the geophone a few feet below the surface to reduce surface noise and planted in more compacr soil. I use a Vernier Software program and hardware with three channel inputs. This works well with nearby seismic events. The software has the ability to mathematically "rotate" the two horizontal geophone elements to help find the direction to the event. Contact me if I can be of more help. Best of Luck, George Erich GeE777@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Charles Patton levitation suggestion... From: meredithlamb@.............. Date: 7 Oct 1999 09:25:58 -0700 On Wed, 06 October 1999, George Harris wrote: > > Regarding materials with negative susceptibilities: > > Perhaps I have missed something along the way, but there are a number of > materials with higher negattive susceptibilities than carbon. The handbook > of Chemistry and Physics (59 th edition - 1979) lists the > following: > > Carbon or diamond -6 > Bismuth (solid) -280 > Aluminum Sulfate (anhydrous) -93 > Aluminum Sulfate Hydrate (Al2(So4)3.18H2O -323 > Calcium Carbonate -38 > Ammonium Nitrate -34 > Ammonium Sulfate -67 > > The values stated are per gram, so the specific gravities are probably > important also. It would seem that the crystal form should be the best if > available. Have any of these been tried? > > George Harris > George, Thanks for the above info. Without the benefit of having any such book and reference, its nice to see such. As I understand it, alot of the recent editions lack any such reference. Part of the mystery with only carbon and bismuth is that theres no guarantee (especially with carbon) that there will even be a diamagnetic field, and indeed it can be paramagnetic (magnetic). As I understand it, some carbon can outperform bismuth. As far as the above reference this immediately brings up the question of what was used to derive thier figures. I would suggest its only drawn from afew samples, and the variation of chemical analysis in their samples probably were only a small portion. I've read where some carbon, has a value of up to -450...but, part of the same "rod" can fail far below that, or even be magnetic. The real mystery is just what it is, that makes some with a certain value, and another sample so very different, from the other? Your calcium carbonate (chalk)reference was very interesting. The crystalline varietys come in calcite and aragonite. The so called "iceland" spar" variety of calcite, too me, might be a interesting object to check out in rock shops, mainly because they would be more likely to have a nice flat surface if any is found that is diamagnetic. Iceland spar is the stuff that shows the double refraction...i.e, a printed page underneath (on better clear specimens), will show a doubling of the print or words. However, being as I've not yet checked it out, who knows what the results would be. I'am also probably concerned that certain specimens may be better than others...but I'am just speculating. Thanks for references, time will tell, with calcite. Overall, I think the mystery continues... Thanks, Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Small Event on oct 6 From: "D. Hill" n0ssy@.......... Date: Thu, 07 Oct 1999 10:57:55 -0600 Did anyone record a small event for the Colorado area on Oct. 6 around 23:55 UCT (I'm at my office and guessing on exact time.) I see a small defelection on the ANMO site in New Mexico at 23:54, but I can not find anything on the internet about any activity for this area /time frame. Dewayne Hill _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: ground emissions From: Doug Sutherland doug@............. Date: Fri, 8 Oct 1999 03:16:13 -0700 Hi There, I was just reading some info on the web about ambient air analyzers, and I found a page for a company called Tekran that has a really sensitive mercury detector (12 parts per quadrillion). On their site they say that one of the potential uses of this is for "seismic prediction through the detection of increased ground emissions". Sounds interesting. I am curious to hear some expert opinions on this subject, and I'm wondering if there are currently projects underway to attempt predication based on mercury or other ground emissions. Doug _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Small Event on oct 6 From: David Wolny dwolny@............. Date: Fri, 8 Oct 1999 06:15:30 -0600 (MDT) Dewayne, I recorded an event with a P arrival of 23:54:00. I had it at ML 3.4. Looks like it might be NE Wyoming. Meredith, did you pick this one up? Dave Wolny Mesa State College 39.07N 108.55W On Thu, 7 Oct 1999, D. Hill wrote: > Did anyone record a small event for the Colorado area on Oct. 6 around > 23:55 UCT (I'm at my office and guessing on exact time.) > > I see a small defelection on the ANMO site in New Mexico at 23:54, but > I can not find anything on the internet about any activity for this area > /time frame. > > Dewayne Hill _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Small Event on oct 6 From: meredithlamb@.............. Date: 8 Oct 1999 07:31:25 -0700 On Fri, 08 October 1999, David Wolny wrote: > > Dewayne, > > I recorded an event with a P arrival of 23:54:00. I had it at ML 3.4. > Looks like it might be NE Wyoming. > > Meredith, did you pick this one up? > > Dave Wolny > Mesa State College > 39.07N 108.55W > > On Thu, 7 Oct 1999, D. Hill wrote: > > > Did anyone record a small event for the Colorado area on Oct. 6 around > > 23:55 UCT (I'm at my office and guessing on exact time.) > > > > I see a small defelection on the ANMO site in New Mexico at 23:54, but > > I can not find anything on the internet about any activity for this area > > /time frame. > > > > Dewayne Hill > Dewayne and Dave, I checked with reading Dewaynes email, but my old recording Packard Bell had froze up. Its starting to do that more often especially in the last 2 weeks. I leave the monitor turned off, so I don't notice these sporadic hang ups right away. I leave it off, when I'am not staying in the area, as I've seen some monitors catch fire over the years. Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Small Event on oct 6 From: John Lahr lahr@................... Date: Fri, 8 Oct 1999 08:38:02 -0600 (MDT) Hi Dave, Are you set up to send arrival times to the NEIC? This one could be helpful, although an arrival from the north would help the most. JCLahr >Dewayne, >I recorded an event with a P arrival of 23:54:00. I had it at ML 3.4. >Looks like it might be NE Wyoming. >Meredith, did you pick this one up? >Dave Wolny >Mesa State College >39.07N 108.55W _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Diamagnetic levitation materials From: "Charles R. Patton" patton@.......... Date: Fri, 08 Oct 1999 16:31:02 -0700 I found another site posting magnetic susceptibilities. Go to: http://www.reade.com/Particle_Briefings/magnetic_susceptibilities.html Unfortunately, the aluminum sulfates mentioned in George Harris=92 list below are not in this list. George Harris posted the following magnetic susceptibility list from the handbook of Chemistry and Physics (59 th edition - 1979) Carbon or diamond -6 Bismuth (solid) -280 Aluminum Sulfate (anhydrous) -93 Aluminum Sulfate Hydrate (Al2(So4)3.18H2O -323 Calcium Carbonate -38 Ammonium Nitrate -34 Ammonium Sulfate -67 Thanks for the additional information, but now I am bothered. I understood from other comments that bismuth was supposed to have the highest constant, but aluminum sulfate hydrate is shown with bigger numbers. Is there some independent reference where we can verify that number? Usually the CRC handbook gives the reference for the data. Could you please post that? Thanks. A small bit of discussion on the above materials. Aluminum sulfate hydrate is soluble in water but decomposes above 86 degrees C. So to get a reasonable solid piece, you could probably slowly, ever so slowly, evaporate a solution leaving behind a cake/crystalline mass. From that viewpoint, ammonium sulfate would be much easier to do something with. It decomposes at 235 degrees C. So you could spray onto a hot surface, building up a shape that would be pretty much void free or boil off the water to leave a solid cake with probably some porosity. The minus 67 number is still better than the minus 6 of carbon, even taking into account densities. My carbon rods are in from McMaster-Carr, so maybe this weekend I=92ll slice=92n=92dice up a test panel=92s worth. A quick test shows that they= are diamagnetic at least. Charles R. Patton charles.r.patton@........ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: ZOLLNER SEISMOGRAPH From: RADIOTEL@....... Date: Sat, 9 Oct 1999 20:14:51 EDT Has anyone heard of the "Zollner" seismograph or horizonal pendulum seismograph utilizing the Zollner suspension. I understand that it solves the boom piviot problem by using two wires which are kept in tension. Therefore, there is no boom pivot contact and hence no friction. Has anyone built one of these? How does it compare to a Lehman seismograph? Jim Allen Cerritos, Calif. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Diamagnetic materials variation From: meredithlamb@.............. Date: 9 Oct 1999 21:39:34 -0700 Hi diamagnetic fans....ha Bob Lamb has forwarded me copys of the Handbook of Chemistry & Physics, relating to the magnetic susceptibility of the elements and inorganic compounds; for the year 1988. Eleven pages of fine print, extensive list which also jumps into various compounds/mixtures. Most interesting besides the list; is where they give more than one value for afew items. Bismuth is one of those, -10.5 (s)on one, and -280.1 (I) on another. The (s) and (I) is not defined. A number of items on the list also exhibit a variation of values. Tin is another one, with +3.1 (White tin)to -37.0 for (gray tin). They do maintain the same value for carbon, but that is obviously wrong as I've had paramagnetic carbon samples more often than diamagnetic samples. I doubt there is any public reference to any range of values, that represent the whole carbon spectrum; which encompasses samples from a broad range of manufacturers, sources, etc. I can't see any manufacturer striving for ultra pure carbon (which doesn't guarantee diamagnetic results) for whatever use it finds. The normal eddy current materials like, copper, silver, gold, are obviously useless for levitation; although they make good dramatic demonstrations of repulsion and eddy current combinations. Tin, zinc, and lead is a unknown too me. Another obvious problem is well known and that is temperature variations strongly affect the floating neo magnet. Even a sudden open door and cooler air, can make the neo drop out of suspension. The larger the neo magnet the more pronounced the effect becomes. Whether other strong magnets like samarium do the same is unknown, and their samples are scarce on the surplus scene I think. Too add to the complexity, the magnet manufacturers also vary their formulas, methods, granularity etc., and this too me, is just another sample of variations of any material, depending on the "cook's" recipes. ....ha. I've had a number of the same magnets, and have had to adjust for variations on each individual one...they all vary somewhat, especially on the diamagnetic levitation scene. Bob reports testing some aluminum sulfate, but while diamagnetic, it wasn't near as dramatic as the listed value of -323.0, and, he says: "but no obvious "strong" diamag apparent - prob. less then Rochelle salt, quartz & few others I tried." Sodium cloride is listed at -30.3 on the 1988 list, quartz is not listed. Am getting to the point that I look upon each element as having different personalities just like humans...they are all different from one sample to the next, especially in diamagnetics. Purity also doesn't guarantee a uniformity in diamagnetism. I have some carbon rods with statements of purity probably going beyond 99.999%, with impurity up to some 4 parts per million, and yes, their diamagnetism varys from one rod to the next....some obviously weaker than another in diamagnetism "levels". Still; these aren't really any better than some 3 other levitation carbon brush assemblys I have. Now...it sure would be nice if levitation co-operated over the years; we might all be running levitation seismometers now.... The mystery continues... Cheers......ha. Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re[2]: ZOLLNER SEISMOGRAPH From: angel rodriguez angel@............ Date: Sat, 9 Oct 1999 21:52:48 -0400 Hello RADIOTEL, Saturday, October 09, 1999, 4:14:51 PM, you wrote: Rac> Has anyone heard of the "Zollner" seismograph or horizonal pendulum Rac> seismograph utilizing the Zollner suspension. I understand that it solves the Rac> boom piviot problem by using two wires which are kept in tension. Therefore, Rac> there is no boom pivot contact and hence no friction. Has anyone built one Rac> of these? How does it compare to a Lehman seismograph? Rac> Jim Allen Rac> Cerritos, Calif. Rac> _____________________________________________________________________ Rac> Public Seismic Network Mailing List (PSN-L) Rac> To leave this list email listserver@.............. with the body of the Rac> message: leave PSN-L Hi, I made a wire under tension pivot that works very well for me. see it at www.barriles.com/gardengate Warmly, Angel angel@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: new program From: The Lahrs JohnJan@........ Date: Sat, 09 Oct 1999 23:59:09 -0600 Hi Dewayne, I took a look at your seismic file generated by the DaTaq AD. I could convert it to psn format with wdq2psn, but there were too many samples to view with WinQuake. So, I wrote another program, wdqtrim, that reads a long .wdq file generated by the DaTaq AD and generates a psn formatted file with a subset of the data. The programs are located here: http://lahr.org/john-jan/psn/source_files/ John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: URL correct? From: offutt@............ (Warren Offutt) Date: Sun, 10 Oct 1999 05:57:52 -0600 (MDT) Angel mentioned that a picture of his tension-hinge seismo was posted on www.barriles.com/gardengate Is this address correct? I get a not found error ... warren _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: URL correct? From: Nick & Sophie Caporossi nickcap@............. Date: Sun, 10 Oct 1999 08:22:52 -0400 Hi Warren: Yes, I don't seem to have any trouble getting it. Try: >http://www.barriles.com/gardengate/ Nick At 05:57 AM 10/10/99 -0600, you wrote: > >Angel mentioned that a picture of his tension-hinge seismo was posted >on > > www.barriles.com/gardengate > >Is this address correct? I get a not found error ... > >warren _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Diamagnetic materials variation From: Karl Cunningham karlc@....... Date: Sun, 10 Oct 1999 09:59:57 -0700 Meredith -- A couple of comments: At 09:39 PM 10/9/99 -0700, you wrote: >Bismuth >is one of those, -10.5 (s)on one, and -280.1 (I) >on another. The (s) and (I) is not defined. A >number of items on the list also exhibit a >variation of values. Tin is another one, with >+3.1 (White tin)to -37.0 for (gray tin). I don't know for sure, but I think the different susceptibilities for bismuth and tin are for different crystal structures. Many materials' molecules can come together in more than one way, depending on the conditions present (temperature, pressure, rate of cooling, etc.) while the crystals are forming. >Purity also doesn't guarantee a uniformity in >diamagnetism. I have some carbon rods with >statements of purity probably going beyond >99.999%, with impurity up to some 4 parts per >million, and yes, their diamagnetism varys >from one rod to the next....some obviously >weaker than another in diamagnetism "levels". >Still; these aren't really any better than >some 3 other levitation carbon brush assemblys >I have. Many properties of compounds can be changed dramatically by *very* small changes in impurities. I don't know if this is the case here, but I wouldn't rule it out. >Bob reports testing some aluminum sulfate, but >while diamagnetic, it wasn't near as dramatic >as the listed value of -323.0, and, he says: >"but no obvious "strong" diamag apparent - >prob. less then Rochelle salt, quartz & few >others I tried." Sodium cloride is listed at >-30.3 on the 1988 list, quartz is not listed. For quartz, see SiO2 (listed under silicon as silicon oxide in the chart). That is the chemical compound of quartz, but again is the issue of matching the crystal structure. >Now...it sure would be nice if levitation >co-operated over the years; we might all be >running levitation seismometers now.... I also wish that springs would be a bit more cooperative with regard to temperature effects. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Zollner-Wenner suspension From: S-T Morrissey sean@........... Date: Sun, 10 Oct 1999 13:08:23 -0500 (CDT) Regarding wire suspensions in seismometers: These have been experimented with since the earliest years of seismometers for making pendulum sensors for horizontal motion. Clearly the most basic is a plumb-bob on a string. But to constrain the degrees of freedom of this mass, two or more suspension wires are neeeded, or else a flat flexure is used as for the pendulum of a grandfather clock. The thin flexure strip is adequate to keep the dish-shaped mass from rotating and banging on the door. For more complete restraint four wires are used as a pair of inverted Vs, one at each end of a rod-like horizontal boom or mass. An example of this is the assembly of in-line chrome balls that are suspended from a wooden frame as an office toy (that actually demonstrates conservation of momentum). This suspension is also used for the dashpots to damp the motion of the Wiechert 80kg inverted pendulum seismometer of the early 1900s. The wires suspend a shaft supporting the pistons that translate within the fixed cylinders. The wires are about 20 cm long (high?) to minimize up and down motion. A number of early optical mirror and moving coil horizontal sensors were made, some with suspensions over a meter high. (a 1 meter simple pendulum has a period of 2 seconds). However, it was quickly realized that longer period sensors were only practical with horizontal boom configurations, as the Bosch-Omori 25kg horizontal sensors of the 30s. The interesting variable is the attachment of the pivot end of the boom at the support post. Some (Milne-Shaw) used a compressional pivot; later a tension member from the back of the support post was preferred, as in large horizontals today. An extreme of the second tension wire is the Zollner suspension, where the taught wire extends as far below the boom as the upper suspension is above the boom. This still required some points of attachment to fix the axis of rotation, and in the Wenner seismometer these became crossed flexures. THis provided a fairly rugged way to suspend a large mass and boom while using lightweight flexures to fix the axis of rotation. It also required a cavity in the pier. The Zollner-Wenner wires had problems with bow-string oscillations which would vibrate from local noises like steps and shorten slightly. In the Wood-Anderson, which is an extreme case of the Zollner opposed wires, the vibration of the wires is damped by oil cups. (The copper mass itself is magnetically damped). Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: mb5.5 Irian Jaya From: Arie Verveer ajbv@............ Date: Mon, 11 Oct 1999 09:06:39 +0800 Subject: Posted event in Wrong Mailing list From: Arie Verveer ajbv@............ Date: Mon, 11 Oct 1999 09:13:11 +0800 Hi, Sorry about this, I posted an event in the wrong mailing list. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Diamagnetic materials variation From: meredithlamb@.............. Date: 11 Oct 1999 20:22:12 -0700 Karl, Tnks for the reply. Crystallization could well have an impact on whether there is or isn't diamagnetism, I just don't know. Impurities could well also play a part...perhaps even as low as .005 parts in a million. Of course being as the likely hood of finding out, could go on forever......we'll leave that up to others. Have done and seen enough with carbons problems with temperature effects, to where, I'll probably go more into bismuth as the "sandwich" element of choice. Although its not the carbon being floated, it strongly responses to temperature and that changes the diamagnetism level, with the magnet being floated. Another note; Bob Lamb forwarded me a 1/2 ounce neo shaped like a tooth. Was able to float it, but had to do frequent adjustments to keep it from contact. The entire sandwich was carbon. I also used acouple bar magnets on the side of the sandwich to eliminate tilting for the most part. Bob also forwarded some bismuth. I used that for the bottom half, and carbon for the top. Strange combo but it works. ................ Some time back someone wanted the internet address for Colorado Futurescience, article on "Testing the Superconductors", that was forwarded to PSN. Seems there is two, one is a mirror. http://www.futurescience.com http://www.websom.com/cfsc/welcome.html The orginal article of "testing the super conductors", no longer appears anywhere on the site. They sell small superconductor kits, and go into other "different" subjects. Thanks, Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Re[2]: ZOLLNER SEISMOGRAPH From: RADIOTEL@....... Date: Tue, 12 Oct 1999 00:06:46 EDT THANKS SEAN AND ANGEL The information you provided was thought provoking. However, for now I think I will stick with a regular Lehman suspension and my velocity copy of Sean's STM-8 which works very well for Quakes in California. Jim Allen Cerritos, Calif. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WASS , was Diamagnetic materials variation From: Ed Thelen ethelen@........ Date: Mon, 11 Oct 1999 21:09:59 -0700 Greetings Meredith Lamb and any other WASS survivors I have given Larry Cochrane all of the old WASS Newsletters that I had. He and PSN seems a very worthy successor :-) (For those of you not in "the inside", WASS was "World Amateur Seismological Society". It was active (at least a quarterly news letter) from before 1971 when I joined to 1977?. We had a paid up mailing list of about 125 mostly passive members (the usual thing). In 1977? I could not find any other poor burned-out fool to be editor/publisher/mailer/treasurer/major-author ... and the "organization" died.) A Meredith Lamb had already been a long time WASS member and had been very helpful. :-) Cheers Ed Thelen P.S. Hope I did not violate too much etiquette. Just joined the Mailing List. meredithlamb@.............. wrote: > > Karl, > .... > > Thanks, > > Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WASS , was Diamagnetic materials variation From: EK kerls@...... Date: Mon, 11 Oct 1999 23:29:22 -0500 And Cheers to you , Ed Thelen , and welcome to the Mailing List Major Edward E. Kerla A.R. Ed Thelen wrote: > Greetings Meredith Lamb > > and any other WASS survivors > > I have given Larry Cochrane > all of the old WASS Newsletters that I had. > He and PSN seems a very worthy successor :-) > > (For those of you not in "the inside", > WASS was "World Amateur Seismological Society". > It was active (at least a quarterly news letter) > from before 1971 when I joined to 1977?. > We had a paid up mailing list of about 125 > mostly passive members (the usual thing). > In 1977? I could not find any other poor burned-out fool > to be editor/publisher/mailer/treasurer/major-author ... > and the "organization" died.) > > A Meredith Lamb had already been a long time WASS member > and had been very helpful. :-) > > Cheers > Ed Thelen > > P.S. Hope I did not violate too much etiquette. > Just joined the Mailing List. > > meredithlamb@.............. wrote: > > > > Karl, > > > ... > > > > Thanks, > > > > Meredith Lamb > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Diamagnetic levitation materials From: George Harris gjharris@............. Date: Mon, 11 Oct 1999 21:44:45 -0400 "Charles R. Patton" wrote:the > highest constant, but aluminum sulfate hydrate is shown with bigger > numbers. Is there some independent reference where we can verify that > number? Usually the CRC handbook gives the reference for the data. > Could you please post that? Thanks. The CRC reference states thus: A more extensive listing of the magnetic susceptibilities of inorganic compunds as well as those for organic may be found in Constantes Selectionees Diamagnetism Relaxation Paramagnetique, Volume 7. The table (it contains about 360 items in the CRC) is abridged from the above reference by permission of the authors. George Harris _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Replica of Chinese Seismograph From: Doug Crice dcrice@............ Date: Tue, 12 Oct 1999 06:24:42 -0700 e-Bay has a replica of the original Chinese seismograph for sale. The seller is in Hong Kong, so I would guess that this is out of the Chinese handicraft industry. There's a picture at: http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&tc=ps&item=179657643 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Notes on diamagnetic material From: meredithlamb@.............. Date: 12 Oct 1999 09:47:36 -0700 Hi all, Forgot to mention, in the Handbook of Chemistry & Physics, circa 1988, for diamagnetic materials, the (s) symbol means "solid", and the (l) symbol means liquid. This note was forwarded to me by Robert Lamb. One could delve forever with different materials, but I would think, the carbon and bismuth are the more cheaper and less toxic materials for levitation. For those interested in more extensive experimentation, I would suggest checking out this commercial web site, for more magnets: http://www.wondermagnet.com/dev/magnets.html The items #9, #10 and #13 would all work and are bigger than the Radio Shack pill magnet. I only got the #13 (a ring neo) from this site. One has to go to the ordering info, to check on availability. The ring and disk neo's are alot easier to levitate. Their is one curved neo, that might interest the traditional coil/magnet crowd, there too, but mounting two such magnets could be somewhat of a challenge to keep them apart. Check out the humor pictures, and references to other sites. Its worth the time to browse and see. Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Discussion list of interest to some PSN-L members From: Doug Welch welch@................... Date: Tue, 12 Oct 1999 15:22:34 -0400 (EDT) Folks, I have recently initiated a list for discussion and distribution of observations of geomagnetic phenomena. Its members are usually amateur observers of geomagnetism who have constructed (or are considering constructing) magnetometers to monitor geomagnetic activity. I'm sure that there are many PSN-L members who have overlapping interests and encourage any and all of you to subscribe and participate. There are two ways to go about subscribing: 1) Go to the URL http://mailman.mcmaster.ca/mailman/listinfo/magnetometry-l and follow directions there. 2) Send an e-mail to magnetometry-l-request@................... with the word help in the subject or body of the message for further instructions. You must be a subscriber to post messages. Best regards, Doug Welch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Levitation heavyweight champ... From: meredithlamb@.............. Date: 12 Oct 1999 13:39:38 -0700 Hi all, Just got a ring magnet from All Electronics Corporation. Its their cat #MAG-50. Its 1.240" in outside diameter, .840" inside diameter, by .250" thick. My postal scale (non-precision)says about ..8 ounce. Am getting the strong feeling that for maximum weight, its the ring magnets that work better than even disk magnets. More mass could mean more enertia stabilility, if temperature problems can be controlled. This is the largest weight I've seen. It floats with one of my carbon units, and acouple side bar magnets. I was surprised! It will be interesting to try bismuth with this sometime. All electronics identifies it as a neodymium magnet; but I have suspicions it could be another element like samarium or ?; as it doesn't seem to have the magnetic attraction of my other neo's...i.e., weaker overall. They come unplated, and have a silver-gray with a tinge of yellow color to them. With this size, vertical vibrations seems to be easily displayed by eye, with the magnet tipping back and forth horizontally. Check out: http://www.allcorp.com See magnetic devices. For the coil/magnet crowd: All Electronics also has a curved neo magnet, but this is nickel plated. 1.735" length X 1.435" X .245" thick. $5.50 plus shipping handling; probably a very good buy if one can build a mechanism to keep the magnets apart. Believe the curve face is somewhere in the neighborhood of some 3-4" diameter, which means one could add magnets for larger coils other than small relay coils. Very nice clean unit, except for some glue deposits on the outside back. Probably a cheaper and better buy than the Forcefield unit, of the prior message. Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: quake coming in From: meredithlamb@.............. Date: 12 Oct 1999 18:59:32 -0700 Hi all, Notice some long period waves coming in. Fairly strong vertical response, but moderate horizontals output. Perhaps a deeper than normal quake? Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: New event From: barry lotz gbl@....... Date: Tue, 12 Oct 1999 19:18:50 -0700 Looks like Alaska is sending us a message. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Levitation heavyweight champ... From: barry lotz gbl@....... Date: Tue, 12 Oct 1999 19:29:46 -0700 Meredith I have thought of maybe taking apart a speaker magnet and replacing the donut with something similar to the curved magnets you mentioned. One may need something like 3 to form a circle and 2-3 to form the thickness. It seems like this magnet material may be stronger than a conventional speaker magnet. Barry meredithlamb@.............. wrote: > --snip-- > Hi all, > Check out: http://www.allcorp.com > See magnetic devices. > > For the coil/magnet crowd: > All Electronics also has a curved neo magnet, > but this is nickel plated. 1.735" length X > 1.435" X .245" thick. $5.50 plus shipping > handling; probably a very good buy if one > can build a mechanism to keep the magnets > apart. Believe the curve face is somewhere > in the neighborhood of some 3-4" diameter, > which means one could add magnets for > larger coils other than small relay coils. > Very nice clean unit, except for some glue > deposits on the outside back. Probably a > cheaper and better buy than the Forcefield > unit, of the prior message. > > Meredith Lamb > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Have large event happening can anyone say were it is coming from. From: EK kerls@...... Date: Tue, 12 Oct 1999 21:50:27 -0500 Maj. Edward Kerls A.R. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: large event From: EK kerls@...... Date: Tue, 12 Oct 1999 21:52:05 -0500 I have event coming in can anyone say were it is Maj.Edward E. kerls _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: WWW.SEISMICNET.COM outage From: Larry Cochrane cochrane@.............. Date: Tue, 12 Oct 1999 21:57:45 -0700 All, Today starting around 11:25 am local time (PDT) my ISP (PacBel ) had several outages lasting a few hours each time. My DSL line is back up again but who knows for how long. This is the first outage I've had for over two months but the fact it lasted for 4 hours the first time and then again for 3 hours is pretty bad.... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: large event From: "J. D. Cooley" cooleyj@............ Date: Tue, 12 Oct 1999 22:16:47 -0700 At 07:52 PM 10/12/99 , you wrote: >I have event coming in can anyone say were it is >Maj.Edward E. kerls > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > 13Oct1999 01:33:40.3 54.7N 161.2W 33 MS=6.3 M*NEI ALASKA PENINSULA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: large event From: EK kerls@...... Date: Wed, 13 Oct 1999 00:47:39 -0500 To J.D. Cooly ; You wouldn't happened to be the J.D> Cooly from around Athens Texas. Maj. Edward >e. Kerls "J. D. Cooley" wrote: > At 07:52 PM 10/12/99 , you wrote: > >I have event coming in can anyone say were it is > >Maj.Edward E. kerls > > > > > >_____________________________________________________________________ > > > >Public Seismic Network Mailing List (PSN-L) > > > >To leave this list email listserver@.............. with the body of the > >message: leave PSN-L > > > > 13Oct1999 01:33:40.3 54.7N 161.2W 33 MS=6.3 M*NEI ALASKA PENINSULA > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Alaska Quake From: S-T Morrissey sean@........... Date: Wed, 13 Oct 1999 01:02:45 -0500 (CDT) Per NEIS: 99/10/13 01:33:40 54.72N 161.19W 33km (deep) 6.3Ms Alaska Peninsula. Nice 60-second+ surface waves here at St. Louis. Did not clip the 12-bit RS digitizer. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Some list rules...was Re: large event From: Larry Cochrane cochrane@.............. Date: Tue, 12 Oct 1999 23:23:51 -0700 All, Lately I have been seeing some emails to the list with "Thanks for the Info..." type messages as well as other message with no interest to the rest of the list members. PLEASE, too keep the bandwidth down on my system this type of message should be sent directly to the sender. When you hit the reply button, the To: address is set to the list address. If the message you are sending only is for the sender please change the To: field. Thanks, Larry Cochrane Redwood City, PSN P.S. I don't mean to pick on Maj. Edward Kerls by reply to this message. But its a good example of what should NOT be sent to the list... At 12:47 AM 10/13/99 -0500, you wrote: >To J.D. Cooly ; You wouldn't happened to be the J.D> Cooly from >around Athens Texas. >Maj. Edward >e. Kerls > >"J. D. Cooley" wrote: > >> At 07:52 PM 10/12/99 , you wrote: >> >I have event coming in can anyone say were it is >> >Maj.Edward E. kerls _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Levitation heavyweight champ... From: meredithlamb@.............. Date: 13 Oct 1999 00:14:39 -0700 On Tue, 12 October 1999, barry lotz wrote: > > Meredith > I have thought of maybe taking apart a speaker magnet and replacing the > donut with something similar to the curved magnets you mentioned. One may > need something like 3 to form a circle and 2-3 to form the thickness. It > seems like this magnet material may be stronger than a conventional speaker > magnet. > Barry Hi Barry, I can't visualize how it would be easy to do that without complicated machining, and, the coil would likely be very large in diameter...not the original coil of the speaker, and also the center pole would also have to be made very large for maximum gauss. Nothing of the original speaker assembly would be of any use, if I understand your description. These magnets when stood upright need separation...the inside curve can't touch any steel attachment of the back polarity. I'am guessing one would need 6 to 8 of these magnets to form a circle (with slight separation) and special everything machining and coil size. I think you are thinking of a different shape than what they are...i.e., a rectangular piece, with a total thickness curve all over, and 1/2 the thickness is one pole, and the other half, is the other pole. If they were magnetized 1/2 the length .....then one could try as you describe. If you are thinking of using the original speaker assembly, and discarding the ferrite magnet donut, and, using flat neo's, then, one could do that. One would need enough neo's for the desired thickness of course. That could make a experimental approach, to check on the old versus the neo change over gauss field of the narrow gap. Economically it probably wouldn't be worth the effort, I would think. The original idea I was thinking of, is too use 2 pieces facing each other, with or without a center pole....i.e., a regular general "U" magnet affair. Sounds rather easy, but, these magnets somehow have to be mechanically held apart, otherwise they crash together into each other and go into pieces, or, implode might be a better description. Still.... they could be useful for that odd diameter coil, that doesn't fit what you/one has. More than likely the inside curve won't match the coil curve of the existing coil, and you wouldn't get the "max" gauss. Even here a steel center pole would probably be needed for the coil for max gauss. Matching the coil to the magnet is a real pain, on the homebrew scene. If one has a 3 piece old magnet assembly where you can move the iron on the ends, attaching these to the inside may work out OK...if the magnet had too big a gap to begin with....but, that depends on the coil of course. One would still need a lockdown on the iron pieces. One note on these magnets....make sure you order say, the outside curve to be like South and the inside to be north...and the other piece to be the opposite, with the inside south, and the outside north...otherwise they repell of course, if they were both the same. All Electronics may or may not consider this....so use the remarks section of the order form, if, you want these curved neo's. Take care, Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: New WinQuake beta release and new PSN Explorer program. From: Larry Cochrane cochrane@.............. Date: Wed, 13 Oct 1999 02:00:47 -0700 Greetings, Today I released a new WinQuake (WQ) beta release. Links to the new release can be found here: http://www.seismicnet.com/software.html. This release has the following features as will as some bug fixes; The event, or seismograph, window now displays the time and amplitude of the cursor as you move it within the window. This information is displayed on the Status Bar. For the amplitude the number is in A/D counts. For the X or time axis WQ will display the time down to the millisecond, if you zoom down to a 10 second or less X Scale. Too get 1 ms resolution WQ interpolates the mouse location between samples since a true 1 ms resolution would require a sample rate of 1K hz. I fixed several problems around saving event files as SAC binary files. WQ now save the event time in the proper field. The problem is I'm not sure if I'm doing it right. If you have access to another program that can read SAC binary files and if that program can display the event time please contact me...I also save the event magnitude in the USER1 field. As far as I can tell there is no defined field for this??? I noticed that the SAC binary created by the IRIS Spyder (http://dmc.iris.washington.edu/DOCS/spyder_alt.htm) system was using USER1 for this info. Unfortunately they do not fill in the event time, so I can't check to see if I'm doing the event time correctly. The major new thing with this release is the PSN Explorer program I wrote in the last few weeks. First some background.. When I started using HTML help files for WQ, Netscape users had no problem using them. People using M$ Internet Explorer would run into a little problem with going to the correct part of the web page. With Netscape, WQ could open a local (on the users hard disk) web page file and have the browser go to the proper section within the help page. Internet Explorer would open the correct page, but would not go to the HTML name tag (sometimes called a bookmark) within the page. Too get around this problem I used a new feature in VC++ 6.0 that lets you create your own program and use Internet Explorer 4.0 (and above) to display web pages within the users program window. Buy creating this new program I fixed the help problem and also was able to easily add a feature to the PSN Explorer that allows the user to download event files from a web page and have WQ open the new file after the FTP download. Heres how too use it. In WQ I added a new tool bar icon next to the report icon and menu items under View. Selecting the New Event File item, WQ will open the PSN Explorer program, or use one that is already open, to display the New Event File page at http://www.seismicnet.com/cgi-dos/event.exe. The user can then select either the GIF image link, this will be displayed by PSN Explorer, and / or select the PSN event file link. If the event file is selected the program will download the file using FTP and then send a message to WQ, using DDE (a way of communicating between programs In Windows), that tells WQ to open the new event file. Before using this feature you must select a directory that will be used for downloads. This only needs to be done once. If you download the new release and find any problems please let me know as soon as possible. I want to get WQ out of beta soon. The next thing, the part I hate the most, is updating the documentation.... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: New WinQuake beta release and new PSN Explorer program. From: "Francesco" franuc@...... Date: Wed, 13 Oct 1999 19:29:08 +0200 Hello Larry I've downloaded the new beta version (.exe file) to upgrade 6.3.3 v. I don't found the icon or menu items about PSNExplorer on toolbar. Althought, I've run the program fron executable file in the directory and it's work well, as the other WQ new features. At least, it's impossible to read the "help" file; this is the error message: "unable to open web broswer", "no default web broswer; can't display web page". (I use MSExplore 5.1). I'm waiting your notice Regards Francesco _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Levitation heavyweight champ... From: barry lotz gbl@....... Date: Wed, 13 Oct 1999 19:25:30 -0700 Meredith I looked at the All electronics catalogue and you are correct. I was thinking of curvature in a different direction. I have some neo magnets that are in the order of 1/4" thick and are curved in the other plane, like the magnets of a harddrive. I bought them at a surplus store a few years ago for $1 each. As many of you may have experienced with surplus stores, you buy a few things thinking they may be of use in the future but when the future comes and you need a couple more the surplus store has sold them all. I see the shape in the All electronics catalogue but they are very thin, and therefore to many would be required to replace the donut. The search goes on. :) Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: LEHMAN CONSTRUCTION From: RADIOTEL@....... Date: Wed, 13 Oct 1999 22:40:38 EDT I am a bit confused regarding the construction of a Lehman (Garden Gate) seismo. Text books at the local university library indicate Garden Gate seismographs with mass of 25 kg or more. However, simular seismographs made by PSN members use masses of about 7 lbs. Why the difference? Is the larger mass more or less sensitive? Additionally, in the text book examples reflecting the principle of the Garden Gate seismograph, they all show the boom slightly tilted down towards the mass end. However, most instructions I have seen on the list I believe states that one should "level" the boom. Which is best for sensitivity - and if the boom should be tilted to what degree is appropriate? A number of pictures on PSN web sites show a long thin rod as part of the boom suspension. Others just show a turn-buckle. What purpose does the long thin rod serve? Any clarification would be appreciated. Jim Allen Cerritos, Calif. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: System backup again. Backup mail server? From: Larry Cochrane cochrane@.............. Date: Thu, 14 Oct 1999 15:23:50 -0700 All, Thanks to PacBell, my system (www.seismicnet.com, webtronics.com and psn.quake.net, they all come to the same computer) was down for almost 2 days. I'm not a happy camper! As of around 2.00 PM local time my DSL service started working again. Hopefully it will stay up this time...It has been up for short periods of time and then down for very long periods of time. This brings up sometime I have been thinking about. We really need a backup mail list server somewhere away from N. California. If/when we have a large local event my system could be down for a long time. If you have access to a system that has a full time connection to the Net and would be willing to host the backup list please let me know. I don't want to use one of the free services. I'm a firm believer in "you get what you pay for"... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Speaker magnet replacement From: "Charles R. Patton" patton@.......... Date: Thu, 14 Oct 1999 16:07:08 -0700 A quick comment on this thread. If you find thin, single poled crescents as opposed to dual-poled crescents (i.e., if you check one face of the crescent, and it has one N or S pole it is single poled as opposed to having a N on one end of the face and a S on the other end of the same crescent face which would be a dual poled unit.), you could easily use them to replace the ferrite magnets in the speaker if you just place a flux bar (soft iron, cast iron, steel, basically any ferrous, relatively high permeability metal) to fill the vertical height to make the combination height equal to the old ferrites being replaced. (look at following in fixed spacing type such as Courier or Line Printer) Sliced view from side of only 1/2 of a symmetrical structure +--Voice Coil Gap | V +--------+ +----------+ | | | | <---Original flux plate | | +----------| | | | | | | | | <---added flux conductor/spacer | | | | | | | | | | +--------+ | | | | <---new high energy magnet | +-----+--------+-+ | | | <-orginal lower flux plate +-------------------------+ P.S. You could use the dual-poled units by grinding a line on the face to mark two equal halves then snapping the magnet into two pieces by using a vise and a hammer or board. The magnets are brittle and don=92t bend, they break. Then you could lay up the magnet pieces with the poles all in one direction. Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lastest Winquake - possible bug From: Larry Cochrane cochrane@.............. Date: Thu, 14 Oct 1999 16:12:28 -0700 Hi Arie, Now that I can send email again.... Looks like the problem is with Win95. According to Microsoft you need to have Internet Explorer 3.0 or later loaded on the system for the Trackmouse event to work. By loading IE, a new DLL (IMHO the whole concept of DLLs was a VERY bad move by M$. The DLL situation is a total mess) is loaded so that the function can be called by WQ. You should not have this problem with Win98 or NT 4.0 (not sure about NT 3.51). -Larry At 08:38 PM 10/13/99 +0800, you wrote: >Hi Larry, I just copied the latest version of Winquake over the Old version >(2.62). >When the Program Icon is clicked the following message is returned. > >The Winqk32.exe file is linked to missing export COMCTL.DLL:_TrackmouseEvent > >I'm running Win95. I can test it on a WinNt system tomorrow if you like? > >All the Best > >Arie > > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: LEHMAN CONSTRUCTION From: Karl Cunningham karlc@....... Date: Thu, 14 Oct 1999 16:24:28 -0700 Jim -- For the regular Lehman design, the amount of mass used does not affect the sensitivity of the seismometer, per se. However, a larger mass makes the instrument less sensitive to convection currents and reduces the effect of any friction in the boom hinge. On the other hand, a larger mass means a more heavy-duty suspension system and perhaps more friction in the hinge. So it is a tradeoff, and there is really no right answer. If you intend to put build this system into a feedback seismometer (such as the VBB approach), there are other design considerations that have a direct relation to the size of the mass. If this is in your plans, do what those design considerations dictate. I'd go with a smaller mass (7 lb or less seems like a good amount) because it is easier to work with and hurts less when you drop it on your foot. Suspension methods (even for amateurs) have improved quite a bit since the original articles were published, which allows the use of smaller masses without sacrificing performance. The use of flexures is generally preferred in the suspension -- they provide a stable hinge with very little friction. In diagrams, the tilt toward the mass end is often exaggerated for the sake of the illustration. In practice it usually amounts to a millimeter or less, and is most easily adjusted by turning the leveling screws in the seismometer base. This adjustment directly affects the period of the seismometer. The longer the period, the more you will be able to see longer-period signals, and the less stable the mass centering becomes. You will probably that with longer periods, you will be re-centering the mass fairly often. Others probably have had more experience with this than I, but periods longer than 20 seconds or so become significantly less stable. A suspension wire is easy to use but can contribute parasitic vibrations itself -- it can vibrate just like a guitar string. Using a rod for the top suspension can increase the frequency of these vibrations enough to be above the frequencies of interest, and this can be filtered out of the signal. Hope this helps. Ask if you have more questions. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... At 10:40 PM 10/13/1999 EDT, you wrote: >I am a bit confused regarding the construction of a Lehman (Garden Gate) >seismo. >Text books at the local university library indicate Garden Gate seismographs >with mass of 25 kg or more. However, simular seismographs made by PSN >members use masses of about 7 lbs. Why the difference? Is the larger mass >more or less sensitive? >Additionally, in the text book examples reflecting the principle of the >Garden Gate seismograph, they all show the boom slightly tilted down towards >the mass end. However, most instructions I have seen on the list I believe >states that one should "level" the boom. Which is best for sensitivity - and >if the boom should be tilted to what degree is appropriate? >A number of pictures on PSN web sites show a long thin rod as part of the >boom suspension. Others just show a turn-buckle. What purpose does the >long thin rod serve? >Any clarification would be appreciated. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: LEHMAN CONSTRUCTION From: TORBEN THAMS tobythams@................ Date: Thu, 14 Oct 1999 17:25:21 +0100 Hi Jim: I completed a modified Lehman prototype just in time to catch the September 30 quake in Mexico. I was test driving it, even though I had not yet installed the damper. I got a very clear signal of both the P and S waves, somewhat to my surprise. My unit uses a 7 pound pendulum mass. The important point is that the top node (where the wire exits the upright post) is slightly off-set from an imaginary vertical line