April 30, 2004

Default source delay

The default source delay, per 1-20 of the manual, is 3 ms. At the moment, I am getting about 7.8 ms between data points. I tried turning the display off, but it made no difference. Next step is probably to take the source delay down to 0 and see how that works. The big question now is how high a frequency I can achieve.

Keithley 6430 Source Control.vi addresses some of these issues. Setting the source delay to 0 took me down to 4.8 seconds. Reducing the amount of data being measured does not seem to make a difference. I'm not sure what else is left that I can do.

Posted by torque at 11:43 AM | Comments (29) | TrackBack

Wal-mart's RFID revolution begins

Wal-mart, along with a number of their suppliers, began using RFID today at a Dallas distribution center. At the moment the tags are by the case and pallet though the end goal is to have the tags on individual items.

Partcipants (per internetnews.com):

Now, who is their (RFID) supplier?

Posted by torque at 11:25 AM | Comments (0) | TrackBack

SREAL buffer read issues - solved

Problem solved. The GPIB read vi and the Keithley 6430 interact in a funny way. If you split the read into two portions, it won't work properly because the last character of the first read shows up in the first character of the next read. The original Keithley 6430 Buffer Read.vi had two problems. The :TRAC:DATA? read was split into three sections: reading the header "#0", reading the data, and then reading the LF (linefeed) character. Because of the error I discussed above, data was not being properly read into labview. In the second read, the byte for "0" shows up before the data, shifting the dataset by 1 byte, this had two effects - it caused the data to read in funny and it caused the primary vi to crash when run again since there were characters still left in the buffer. I solved the problem by reading the entire block, +1 extra character in one swoop, and then stripping the first two characters out before conversion. You need the extra character so that it doesn't leave the LF in the buffer. If you don't have it the next run will crash.





Download file

Posted by torque at 10:39 AM | Comments (0) | TrackBack

Cornbread muffins and smoked Gouda

coverThis morning I found another winner in The Best Recipe - Northern cornbread. I had to make some substitutions. I had no butter, so I used 2 tblspoons olive oil instead. I had no buttermilk, so I replaced it with milk. It worked! It was especially tasty with the smoked Gouda from yesterday.

Posted by torque at 9:16 AM | Comments (1) | TrackBack

April 29, 2004

Lookin' into the crystal ball

Peter, Ken and I had a great discussion on crystal ball-based communication. Turns out that a Massachusetts-based company called Actuality Systems has been working on a crystal ball display for sometime now. Check out the photo gallery, it's quite impressive. They even tell you exactly how it works. They describe the device as a 360-degree-viewable volumetric 3-D display with a resolution of 768 x 768 x 198 and a 24 Hz volume refresh rate. The apparatus contains an embedded graphics processing system, and uses dithering methods to create images of 3-bit to 21-bit-stippled color, which is perceived as several hundred colors. How much is it? I couldn't find a price on their website, but I did find it in this UK-based site: $80738.95. Ouch, though if you are one of the first 50 buyers, they'll give you a free Dell PC worth $2200. Whoo-hoo. Here's the datasheet. They offer their patents for licensing.

I found the price, it is in their powerpoint slides: ~$40K. Oh, also hidden in there, they now have $11M in funding and about a dozen very high end clients.



Posted by torque at 5:15 PM | Comments (0) | TrackBack

Arbitrary source waveforms

A very nice feature of the 6430 is the capability of generating source waveforms, up to 2500 points. Programmatically it is a bit awkward. Source points are entered 100 points at a time, in comma-delimited format. For the first 100, you use :SOURce:LIST:CURRent <first 100 in list> where the list for current can range from -105e-3 to 105e-3 and the voltage from -210 to 210. It's not clear, but I think you also have to set :FUNCtion:MODE properly. After that you use APPend, as in, :SOURce:LIST:CURRent <next 100 in list>. If we wanted to source current, we would do something like

:SOURce:LIST:CURRent .001, 0, .01, 0, .005, ...;   (1 mA, 0 mA, 0 mA, 5 mA)
:SOURce:LIST:CURRent:APPend .5, .4, .0, .01, ...

Posted by torque at 4:32 PM | Comments (0) | TrackBack

Dutch auction

One of the most anticipated and unusual factoid regarding the upcoming Google IPO is that it will be conducted using a Dutch auction. As you may know, in most IPOs, underwriters price the initial offering and then give first dibs to clients, friends and family.

In a Dutch auction, the issuer and the banker give up their discretion over pricing and allocation. The final IPO price is at least close to the highest price the market is willing to pay, rather than at a deflated pricing level that all but ensures no-risk gains for favored players.
While unusual, this Dutch-auction offerings won't be the first. RedEnvelope, Overstock.com, Salon.com, Ravenswood Winery, Briazz and Peet's Coffee all went public using this technique. Note that in their filing, Google states that the IPO price will be primarily based on the auctions - there may well be other factors to prevent things from overheating.

RedEnvelope went public September 2003. Approximately 2.2 million shares were offered through WR Hambrecht & Co.'s OpenIPO system. As a result, shares were priced at $14 resulting in $29 M in net proceeds. Hambrecht & Co. have a nifty flash demo of how it all works. OpenIPO is not exactly a Dutch auction system, but it retains most elements. It is based on work by Nobel Prize-winning economist William Vickrey. You can read more on his work on auctions at the National Academy of Sciences.

Posted by torque at 3:44 PM | Comments (1) | TrackBack

Google files for $2.7 billion IPO

How about that... after all the anticipation. Forbes has a cool comparison between Google and Yahoo. Most striking? Google revenues $1 billion, Yahoo! revenues, $1.6 billion.

Posted by torque at 12:21 PM | Comments (0) | TrackBack

Straus milk

straus.gifWe've bought three 1-quart glass bottles of Straus organic milk for #1 over the past couple weeks. At Mollie Stone's this morning, after reviewing the pricing ($2.69 for a quart) and comparing it to everything else, I just couldn't do it. I ended up buying Clover organic milk ($5.99 for a gallon), which touted exactly the same benefits minus glass bottle. Straus is so high end you can actually buy it online. I wonder if there is any way to bring the price down, maybe I can start a milk delivery truck after I graduate.

In related news, Straus is testing distribution through Costco at three northern California stores (Santa Rosa, Novato and Rohnert Park) though these will come in two gallon plastic bottles. "Don't worry, we are NOT discontinuing our milk in glass bottles...it just won’t be at Costco."

You can tour the Straus Family Dairy:

Straus Family Creamery of Marshall, 60 miles north of San Francisco on Tomales Bay, is opening its doors for tours designed especially for children. The organic dairy and creamery will host 90-minute tours, in which children and their parents can feed calves, become educated about organic practices, see cows being milked and help make butter. The price is $5 per child and $15 per adult.

So far, tours are scheduled from 10 a.m. to 12:15 p.m. May 18, June 1, June 25, July 6, July 23, Aug. 3, Aug. 19 and Sept. 14. To register: e-mail maya@ strausmilk.com, or call (415) 663-5464, extension 111 and leave your fax number or e-mail address so that registration forms can be sent.


Posted by torque at 9:08 AM | Comments (1) | TrackBack

Organic breakfast

The boys and I went to Mollie Stone's early this morning. We came home with one of the best breakfasts we've had in a while: organic Braeburn apples, smoked Gouda from Holland, and Acme Italian bread (made from organic wheat flour). In retrospect it was kind of pricy, but boy was it tasty. Sonja commented that Acme bread can be found almost everywhere, at Andronicos, at Mollie Stone's, at Costco... we'd like to take a factory tour sometime, anyone else up for it?

Posted by torque at 8:57 AM | Comments (1) | TrackBack

April 28, 2004


I was able to get my data acquisition vi to work properly, but only when the storage mode was set to ASCII. When set to Single precision REAL, read buffer returned what seemed like junk data. It isn't really clear why.


I'm getting close. There are some subtle bugs in the Keithley 6430 Buffer Read.vi having to do with SREAL acquisition. If you look at the raw data coming back from the machine, the header is actually three bytes, not two. There is also a line feed (LF, #010) at the end.

Posted by torque at 12:00 PM | Comments (1) | TrackBack

Single-crystal superalloy turbine blades

I met Morgan, one of Professor Melosh's students, this morning. In his prior life at Georgia Tech, he did a project on modeling fatigue in superalloy turbine blades at GE. Amazingly, they can now make 30-lb single crystal nickel-based superalloy turbines. These are used in generators and are expected to have useful lives exceeding 40 years. The secret of making such large single crystals is in the turn. You start with a number of crystal nuclei and grow these in the same direction. When they hit a turn, the fastest growing crystals grow faster, since they have first access to the media. Eventually, if you turn enough times, there will only be one. You then grow this into a mold. Cool huh? This corkscrew mechanism is called a grain selector. Here's a description from an article on monitoring growth using x-ray diffraction:

During casting experiments, a metal alloy charge is placed in the crucible of the mold. After a 1 Pa vacuum has been established, the gate valve is opened, and the ram raises the mold into the hot zone of the furnace. The alloy melts, filling the mold. Solidification of polycrystals initiates at the base of the mold in the starter block where the alloy contacts the water-cooled ram. The fastest-growing grain reaches the grain selector (a corkscrew-shaped section of the mold) first and blocks growth of all other crystals with differing orientation. If the thermal conditions are correct, growth of a single-crystal continues upward in the mold as the mold is slowly withdrawn (150 mm/h) vertically from the furnace. Polished and etched sections of the completed castings showed a dendritic structure with several phases and an absence of grain boundaries.

I wonder if this technique is being used to grow holographic crystals. Turbine blades like the ones I talked about are used in power plants and in jet planes.

Posted by torque at 11:19 AM | Comments (5) | TrackBack

April 27, 2004

High performance testing for bisphenol A

Several weeks ago, Watabe et al. published an article in the Journal of Chromatography on ultra-low level detection of bisphenol A (BPA) in environmental water [1]. BPA is a known endocrine distruptor and the center of brewing controversy regarding the use of polycarbonate material. Watabe et al. implemented high-performance liquid chromatography (HPLC) to achieve a sensitivity of 0.36 ng/L. This method was used to probe environmental water and purified water samples containing 2-70 ng/L of BPA.

The article itself is quite in depth, and worth a bit more reading. One thing that piqued my interested while skimming was

For ultra-low concentration of BPA analysis, BPA contamination from manual pretreatment procedures as well as adhesive for fixing needle of manual syringes affects the determination seriously. This means manual syringes cannot be applied to BPA microanalysis. To obtain reliable quantitative results at ppt concentration level, a column switching auto pretreatment system is essential.

Even employing this HPLC system, we unexpectedly encounter serious contamination problem due to BPA existing in purified water. A water purification system cannot remove BPA completely. A few ng/l level of BPA contamination often found in the purified water is not negligible and the contamination level varied daily. Consequently, there is no reliable way to correct a degree of contamination by calculation.

We have to obtain BPA-free water for preparing BPA standard solution otherwise reliable calibration curve cannot be created. BPA-free water was obtained by filtrating the purified water through Empore disk. Then the contamination was suppressed below the detection limit afforded by this HPLC system. Standard aqueous solution of BPA at 1, 10, and 100 ng/l were injected repeatedly (n=5) to estimate the repeatability of peak area and the results were shown in Table 1. A linear calibration curve with a correlation coefficient >0.999 was obtained. The recovery at 100 ng/l was 100.5% and even a trace of leaking and/or carry-over of BPA was not observed at same concentration. The detection limit estimated by utilizing standard deviation of y-intercept of calibration curves was 0.36 ng/l, which is quite low concentration.

[1] Y. Watabe, T. Kondo, M. Morita, N. Tanaka, J. Haginaka and K. Hosoya, "Determination of bisphenol A in environmental water at ultra-low level by high-performance liquid chromatography with an effective on-line pretreatment device," J.Chromatogr.A, vol. 1032, pp. 45-49, Apr 2. 2004.

Posted by torque at 6:14 PM | Comments (0) | TrackBack

More on the FDA approval of aspartame

I found a brief case study on the approval of aspartame in Enhancing the Regulatory Decision-Making Approval Process for Direct Food Ingredient Technologies: Workshop Summary from the Institute of Medicine [1]. In this account, the approval process is framed with considerably less hype and with very thorough references, e.g., FDA documents.

In 1973, midst the controversies surrounding the use of cyclamate and saccharin, G.D. Searle & Co. submitted a food additive petition for aspartame. This was approved certain "dry" uses, i.e., as a tabletop sweetener and in cold breakfast cereals, powdered beverages, desserts, dessert toppings and chewing gum, but with a caveat. Labels of products containing the sugar substitute were to include the statement "Phenylketonurics: Contains Phenylalanine" as a warning to those with a rare genetic defect preventing the metabolism of phenylalanine, a chemical component of aspartame. Thus, the impression that I and some others may have made that aspartame had been actively rejected by the FDA until Commissioner Hayes is incorrect.

Following the FDA's approval, a number of individuals filed objections and requested a hearing. In conjunction with data discrepancies by a contract laboratory in the toxicological testing of other substances, the agency decided to stay the approval's effective date pending a hearing. Four years later, the FDA convened a three-member Public Board of Inquiry to conduct the hearing. This was quite unusual. Under most circumstances, such a hearing is conducted by an Administrative Law Judge. In this case, the objectors agreed to a modified procedure in which the objectors submitted a list of names from which Board members were then selected.

The Board, while agreeing with the FDA's assessment that aspartame posed no risk to causing brain damage or neuroendocrine function, nevertheless recommended against approval due to unresolved questions regarding brain tumors discovered in rodent studies. This was rejected by the Commissioner who affirmed the original ruling in 1981. It should be mentioned that the case study fails to mention that the Commissioner had been freshly appointed by the Reagan administration. In his decision, the Commissioner commented that "[few] compounds have withstood such detailed testing and close scrutiny". One year later, as a floor amendment to a bill amending the Orphan Drug Act, Searle was granted a patent term extention "to restore some of the time lost during the lengthy delays in securing final FDA approval". This amendment was proposed by Hon. Henry Waxman, who explained it simply as "the Senate amendment extends the patent for a food additive".

In 1982, Searle petioned to have the ruling amended to allow the use of aspartame in carbonated beverages. This was approved the following year. Though several persons filed objections requesting an immediate stay and a public hearing, these were rejected without hearing. In 1985, Community Nutrition Inst., a consumer group, brought a judicial challenge to approval for use in carbonated beverages. The court affirmed the FDA ruling, finding that "the FDA properly denied a hearing after finding that petitioners have raised no material issue regarding the safety of the wet use of aspartame".

Subsequently, the FDA continued to approve additional uses, each time rejecting objections and denying hearing requests, finally approving a petition that aspartame be permitted for use as a general purpose sweetener in 1996.

[1] Institute of Medicine . Food Forum, Enhancing the regulatory decision-making approval process for direct food ingredient technologies : workshop summary, Washington, D.C.: National Academy Press, 1999.

Posted by torque at 5:39 PM | Comments (1) | TrackBack

SENSe1 subsystem - CONCurrent

Per 17-54 of the manual, in order to enable the 6430 to measure more than one function simultaneously, you must use :FUNC:CONC ON. After you do this, you will still need to turn the various functions on and off, e.g., :FUNC:ON "CURR","VOLT". Note that each function in the list must be enclosed in quotes. To get voltage, current and resistance, you can use :FUNC:ON:ALL or just :FUNC:ALL. Now, what is not clear is how choosing all versus just one makes a difference in how fast one can do the measurements. Presumably when measuring impedance you would want both current and voltage.

I wish there was a simple way of searching through vi's for a particular string of text. As it is, you have to open each one and skim through the block diagram.

Keithley 6430 Data Format.vi

  • :FORM:ELEM ...

Hmmm, in 13-2 it says that when changing from local to remote operation, concurrent measurements are enabled. I'm not sure why it isn't working properly then.

Posted by torque at 2:02 PM | Comments (0) | TrackBack


I decided on using the larger pre-built Keithley vi's. While they make life a bit simpler, they can sometimes have too many options. I'm stuck at the moment on the trigger configuration vi. The command in question is the direction: TCON:DIR SOUR or TCON:DIR ACC. I took a look at the triggering flowchart, but that only confused me more.


From the flowchart, it looks like the difference between SOUR and ACC is whether it waits for an external event. It seems like I should choose SOUR if I have no external triggering. But then why is ACCeptor the default?

Posted by torque at 11:01 AM | Comments (0) | TrackBack

April 26, 2004


I had a unique opportunity to go to the SpinAps launch at IBM Almaden today. SpinAps stands for the IBM-Stanford Spintronic Science and Applications Center. As some of you might know, I did my qualifications exam on spintronics. More on this later.

Posted by torque at 4:35 PM | Comments (0) | TrackBack

April 25, 2004

Kodak DX6490

I've been thinking about getting a DX6490.

Posted by torque at 4:18 PM | Comments (0) | TrackBack

Food for the needy

If you have large quantities of leftover food, say, from a wedding reception, consider donating it to the Urban Ministry of Palo Alto.

Posted by torque at 2:15 PM | Comments (0) | TrackBack


I'm always amazed how short the book of Philemon is. This morning I used BibleGateway's Listen to this (NASB) while making pancake mix. In what seemed like no time, the narrator was saying "end of the book of Philemon". The book of Philemon is a letter from Paul to a Philemon regarding Philemon's runaway slave, Onesimus, who was converted.

Posted by torque at 7:28 AM | Comments (0) | TrackBack

April 24, 2004


At Mike's birthday party today I saw a Spirograph-like toy, made in China, with no indication of the word "Spirograph". Very cheap but perfectly functional. Did the patent expire? Was there ever a patent? I spent a lot of time with this toy when I was young. I found a version at Amazon, though this also looked very cheap and not at all like the original, not to mention being out of stock. I found some that looked like what I played with on eBay. I guess they really don't make them like they used to.

As you might have expected, I immediately thought of ways I could implement an online version. Fortunately for my dissertation, a lot of other people already have. Anu Garg wrote a particularly nice Spirograph java applet. Play with it!

Created by Anu Garg

The Spirograph was invented by Denys Fisher (1918-2002), a mechanical engineer from England. Using interlocking wheels, it allowed anyone, young or old, to make incrediblely intricate patterns by simply following around the main wheel with a smaller wheel through which you put the point of a pen. Fischer introduced the Spirograph at the 1965 Nuremburg International Toy Fair where it was picked up by Kenner. In two years, 5.5 million sets had been sold, making it the number one toy in the U.S.. For more on the history of the Spirograph and other toys check out David Hoffman and Viktor Budnik's Kid Stuff: Great Toys from Our Childhood. Interestingly, Fischer conceived the idea while doing research on new design for bomb detonators for NATO.

Can't stop? Want more?

  • Wolfram Research's mathworld, quite specifically, defines a spirograph as a hypotrochoid generated by a fixed point on a circle rolling inside a fixed circle.
  • A spirograph creates roulette guilloché patterns, interestingly, the patterns on paper currency are made using related, but more sophisticated, methods
  • Spirograph from 1965 on eBay, first edition!
  • Oh wow... Denys Fisher, the Fisher of Fisher-Price? No, Fisher-Price was founded in 1930 by Herman Fisher, Irving Price and Helen Schelle.
  • US3230624, as well as other Fisher patents

Posted by torque at 9:35 PM | Comments (0) | TrackBack

The Kingdom of God

Haile (see previous post) spent quite a bit of time on conceptions of heaven and hell. Heaven is the ultimate manifestation of the kingdom of God, i.e., the place where God is king. In Heaven, God's rule is absolute. For those in who are already in the kingdom of God, i.e., God is already king in their lives, this will be a joyful continuation. Hell is the ultimate manifestation of God not being the king, so, the world without God. For those who don't already have God as king, this will also be a smooth transition, for instance, from coveting to lusting, from lusting to murder.

Posted by torque at 9:22 PM | Comments (0) | TrackBack

Peter Haile

Today Peter Haile spoke at a church about the necessity of letting God rule our lives. The kingdom of God is not a place that is going to come into being, or place that we go when we go to heaven. The kingdom of God is wherever God is king. He asked an interesting question - when you woke up this morning, who ruled you? Who dictated how you should feel, act or react? At every moment of our lives, we have a god that we serve. That god might be our ego, our fear, our lust, our bitterness, our pleasure, our joy, our guilt, or, it may be Jesus Christ.

I thought about it. This morning, when I got up (at 5), I was ruled by #2, who was crying. I picked him up and took him downstairs. When I sat down, he cried, so I stood up. When I stood still, he cried, so I walked around. Was not my son my god? Well... not exactly. I wanted him not to cry because (1) it isn't a pleasant sound, (2) he was "suffering", and (3) he'll wake #1 and wife. With some introspection, I concluded that I was most concerned about (3) - because, being somewhant analytical, I always predict in my head what will happen in the future. If #1 and wife are tired then the chance of all of us having a lousy day will be rather high, which means that when I come home it won't be so pleasant.

My conception of the future is often my god. When we are late to an event, I think about who we might offend. I expect to be somewhat upset. And, as a result, I really do become upset. Isn't that stupid? I'm upset because I think I'm going to be upset in the future. Of course, the magnitude of this depends on how much sleep I've gotten, as well as how the day went. Two gods are probably at play there, Fear and Ego. I certainly want to be thought of as being responsible, being a capable manager of my family and a model citizen in the communities I'm in. Aren't these things good to strive for?

One of Haile's striking comments was on motivation. There are lots of "good" reasons to do things. For instance, it is good to be kind to neighbors... because it fosters tighter communities who can synergistically obtain a better and happier life. True... but the reason we should do it is because that is the sort of person Jesus is, who loves his neighbors regardless of who they are. We should pay our taxes so that the government will have resources to build roads, bridges, etc. True... but we should do it because Jesus did it. Thinking in this manner gives us the capability of doing good on earth regardless of the consequences. Why? Because we no longer do things to achieve a particular result, do it because that is the character of Jesus.

Posted by torque at 9:07 PM | Comments (1) | TrackBack

April 23, 2004

Vita-mix container

I sent an inquiry to the Vita-mix folks regarding our blender's polycarbonate container after reading a few articles on chemical leaching from polycarbonate materials. A swift response:

Dear Tim:

In response to your inquiry, the polycarbonate container is made from LEXAN and is approved by the FDA.

The information you are referring to is most likely from the vom Saal study. The study has not been replicated in any larger studies and when you do not see the effects, it certainly casts doubt on relying on one study and ignoring the larger ones.

George Pauli, director of the product policy at the US FDA agency said the agency is following the low dose issue and has seen no reason to take any actions addressing the bisphenol A issue. (GE - letter dated /6/8/99)Pauli said that bisphenol A leaches from polycarbonate baby bottles only under exaggerated conditions. If you heat a bottle with heat and liquid long enough, you can reverse the polymerization to a certain extent. He said that the testing conditions used by Consumer Union (see E/E Letter Vol. 5, no. 8 & 5) which included boiling bottles for 30 minutes, are not realistic. Additional information can be found on the American Plastics Council web site at www.plasticsinfo.org

I hope this information helps to identify your concerns. I would suggest not heating the milk in the polycarbonate container if you are concerned about your safety. If you are blending the soy milk in the container until it heats, I would blend the soy milk and then heat it on the stove.

Sandy Ventimiglia
Customer Service Manager
Vita-Mix Corporation
8615 Usher Rd.
Cleveland, OH 44138-2199
1-800-848-2649 ext. 5304

Posted by torque at 3:31 PM | Comments (2) | TrackBack

A test of the scripturizer

Beloved... let us love one another. I John 4:7-8.

Posted by torque at 2:40 PM | Comments (1) | TrackBack

Installing the scripturizer

Rob Hulson has a good post on the scripturizer for dummies. Though the Scripturizer.pm link doesn't seem to work. Here's what I did:

  1. Go to the version 1.2 blog and copy and paste Scripturizer.pl
  2. Go to the version 1.3 blog and copy and paste Scripturizer.pm
  3. Make phillips change (line 67)
    my $verses = qr{ \d+ (: \s* \d+)* (?: \s* [-&] \s* \d+)* (: \s* \d+)* }x;
  4. Copy Scripturizer.pl to your mt/plugins/Scripturizer.pl, mt/extlib/Sermonizer/Scripturizer.pm changing permissions to 755
  5. Replace all occurrences of <$MTEntryBody$&rt; in your templates with <$MTEntryBody scripturize="NASB"$> choosing your preferred version
  6. Rebuild

Posted by torque at 1:58 PM | Comments (2) | TrackBack

Surf the web with labview

Ok, this is not really related to the 6430 - only sort of. It turns out that labview has TCP vi's which are pretty easy to use. After changing text on the 6430 display yesterday, I started thinking about fun things I could put on it... like stock quotes or maybe a news ticker. I know, it's silly. For what it is worth,

You might use this technique to inteface your labview instrument with an external database, which could be quite useful. Of course, this could also be done with ODBC and LabSQL.

Posted by torque at 11:43 AM | Comments (0) | TrackBack

Aspartame approval

Several weeks ago, lawsuits were were filed in three separate California courts against twelve companies producing or using aspartame as a sugar substitute in their products. This was reported in the U.N. Observer & International Report which, admittedly, seems rather sketchy. The article was released by the World Natural Health Organization and the National Justice League. While most of the arguments were familiar. this paragraph caught my eye:

Since its discovery in 1965, controversy has raged over the health risks associated with the sugar substitute. From laboratory testing of the chemical on rats, researchers have discovered that the drug induces brain tumors. On Sept 30, l980, the Board of Inquiry of the FDA concurred and denied the petition for approval. In l981, the newly appointed FDA Commissioner, Arthur Hull Hayes, ignored the negative ruling and approved aspartame for dry goods. As recorded in the Congressional Record of 1985, then CEO of Searle Laboratories Donald Rumsfeld said that he would call in his markers to get aspartame approved. Rumsfeld was on President Reagan's transition team and a day after taking office appointed Hayes. No FDA Commissioner in the previous sixteen years had allowed Aspartame on the market.
Wait a second, did that just say CEO Donald Rumsfeld, as in Secretary of Defense Donald Rumsfeld. That's scary. Oh man, it is. Wild.

Posted by torque at 8:30 AM | Comments (2) | TrackBack

Chemistry by taste

In 1965, while developing an ulcer drug, James M. Schlatter at G.D. Searle accidentally tasted one of his compounds and discovered aspartame. Recalling the event, said Schlatter, "Some of the powder got onto my fingers. When licking my finger to pick up a piece of paper, I noticed a very strong, sweet taste." While this approach of discovery might seem somewhat haphazard, perhaps even dangerous, it was by no means novel. Saccharin, the oldest artificial sweetener, was discovered in 1879 while Ira Remsen and and Constantine Fahlberg were synthesizing coal tar derivatives. Fahlberg discovered the sweetness of one of the compounds at dinner after not thoroughly washing this hands. To uncover which compound, he returned to his lab and sampled bottle after bottle of his chemicals searching for what he had tasted. Thus saccharin was discovered [1].

[1] I. Flatow, They all laughed-- : from light bulbs to lasers, the fascinating stories behind the great inventions that have changed our lives, New York: HarperCollins, 1992, pp. 156-160.

Posted by torque at 8:04 AM | Comments (2) | TrackBack

Plastics and food

Be careful with what kind of containers you use to store and heat food. Sonja has been doing a lot of research on plastics over the last few days. You might wonder, if the type of plastic, e.g., #2, #3, #4, makes any difference, or even what they are. It does. Chemicals can leach from plasticware. She sent me two links that I found facinating if not slightly shocking.

  1. Shopper's Guide to Plastics & Food: Alternatives to the Problem Plastics
  2. Shopper's Guide to Plastics and Food
Biggest no-no? Polyvinyl chloride, most often found on plastic wrap. Yes, that plastic wrap. Guess who makes my Costco-purchased stretch-tite plastic wrap? Polyvinyl Films, Inc. Check out the PlasticProducts at a Glance chart for plastics found in different brands.

Now, the question is, how much of this is hype and how much of it is substance? More on this to come...

Posted by torque at 7:03 AM | Comments (0) | TrackBack

April 22, 2004

6430 display config

Be careful when you use the Keithley 6430 Display Config vi. You must set the displayed resolution otherwise you will get error -222. This is because the default value for the displayed resolution is "<4>" and not "4".

An alternative to entering the number is actually fixing the vi. If you look, Displayed Resolution is entered into the GPIB code using a knob. The knob itself uses text labels "4,5,6,7" to output numbers "0,1,2,3" to which the vi adds 4.


You can see the text labels by right-clicking on the Displayed Resolution icon and selecting the "Text Labels" tab.


It's clear from hear that the default value should be 0, not 4. To fix this, click on the "Data Range" tab. You'll have to first change "Minimum" to 0, then change "Default value" to 0, then change the "Maximum" to 3.


Now when you use the vi, it should work without filling out Display Resolution. If you do add a constant, you'll see that the default is "4" instead of "<4>".

Posted by torque at 5:17 PM | Comments (0) | TrackBack

Feed control

This post regards the buffer control command, :TRACe:FEED:CONTrol. There are two parameters, NEXT and NEVer, discussed in 17-101. NEXT "fills buffer and stops" while NEVer disables buffer storage. In some previous code, I wrote

This tells the instrument to stop storing information in the buffer and then clears the buffer. Pretty straight-forward. If you do this, you must remember to call :TRAC:FEED:CONT NEXT in order to resume buffer storage.

Posted by torque at 4:13 PM | Comments (1) | TrackBack

Books for emergent parents

We got What to Expect When You're Expecting and What to Expect the First Year from our insurance (Blue Shield) both of which came in handy. We also had about half-a-dozen other books from friends that were ok, but not really necessary. The Expectant Father: Facts, Tips and Advice for Dads-To-Be was a decent read. It had some good tips about planning financially and I particularly liked the comics. Browse this one first though.

When your kid starts eating solids, I highly suggest Ruth Yaron's Super Baby Food. We got a lot of use out of it (still use it) and learned how to make yoghurt from milk to boot.

Posted by torque at 1:59 PM | Comments (0) | TrackBack

Aspartame and formaldehyde

In [1], Hill and Belsito report on the case of a 60-year old Caucasian woman with a 6-month history of eyelid dermatitis. Despite application of a corticosteroid-containing ointment and discontinuation of eyelid cosmetics and nail polishes for 2 months, her rash did not clear. Several years back, in response to a facial dermatitis, she had been patch tested and found to be allergic to formaldehyde, quaternium-15 and fragrances. As expected, her facial dermatitis was resolved by swtiching to formaldehyde-, quaternium-15- and fragrance-free facial and nail cosmetics.

For this current condition, she was again patch tested. Positive reactions occured to formaldehyde (++), quaternium-15 (++), diazolidinyl urea (+), DMDM hydantoin (+) and imidazolidinyl urea (++), with her hair care products and cleansers containing multple sources of these. She was instructed on ways of avoiding such allergens, with particular emphasis on formaldehyde and formaldehyde releasers. Despite doing so for three weeks, her condition improved only slightly. A local pharmacist suggested avoiding aspartame, which she had started using as an artificial sweetner 5 months prior to the onset of her condition (approximately 80 mg per day). Within a week of discontinuing use, her eyelid dermatitis was resolved completely and has yet to recur.

The resolution of the case, of course, naturally suggests that the aspartame was the cause of her eyelid dermatitis. Indeed, following consumption, aspartame is hydrolyzed in the intestine to phenylalanine, aspartic acid, and aspartic acid methyl ester. The methyl ester is converted into methyl alcohol (methanol) and carried by the portal vien to the liver. Here it is oxidized into formaldehyde and then converted into formic acid by alcohol dehydrogenase, aldehyde dehydrogenase and the microsomal oxidase pathway. This process occurs not just in the liver but in other parts of the body containing these enzymes, including the eye.

To be fair, previous studies have shown that does of aspartame beyond 100 mg/kg are required to raise methanol blood levels, hence formaldehyde and formic acid, above contol. This correponds to drinking 35 cans of diet beverage in one sitting for a 70 kg person. Nevertheless, it may well be the case that blood and urine are not the right places to look for formaldehyde.

[1] A.M. Hill and D.V. Belsito, "Systemic contact dermatitis of the eyelids caused by formaldehyde derived from aspartame?" Contact Dermatitis, vol. 49, pp. 258-259, Nov. 2003.

Posted by torque at 12:31 PM | Comments (0) | TrackBack

Aspartame - the science and politics

A scientific-sounding email linking aspartame, a.k.a. Nutrasweet, and multiple sclerosis and systemic lupus was recently circulated to me. While the letter itself has been debunked by the Urban Legends Reference Pages, the prevelance of anti-aspartame sentiment on the web (9/10 of the top 10 hits on Google) suggests there may be something more to this. What's going on?

A search on Pubmed for 'aspartame' yields 754 published scientific papers from 1973 to 2004. A search on Biosis matches 1283 records, though a large number of these have to do with the chemistry of aspartame (and these dealing with important subjects like how to control the release of aspartame from chewing gum).

Posted by torque at 9:49 AM | Comments (285) | TrackBack

April 21, 2004


Blogheads (enoch...), if you haven't yet, check out the Ping-o-Matic!. Now, shouldn't there be an MT Plugin that does this?

Posted by torque at 1:45 PM | Comments (2) | TrackBack

Buying in bulk... seriously

Buying diapers from Costco is still not buying in bulk. How low can it really go? I live on campus with many other families, so the density is there. I found Discount Warehouse (800.946.8736), an inventory closeout site which sells by the truckload (40' trailer). They claim on their site as low as $2.25 per package - but of course, you'll have shipping costs, and, unless the whole village comes to buy the diapers, storage costs. I called them this afternoon and found that none are available at the moment. Liquidation.com might be another place to look.

Posted by torque at 1:22 PM | Comments (1) | TrackBack

Buying diapers... at Amazon?

Enoch did the first analysis. Here's mine. We currently purchase diapers from Costco which come in packages with 4x the number of diapers of the Jumbo Pack (at least for the UltraTrim). I'll have to check on the pull-ups, which we also buy (or someone can comment on how many and how much). The Costco package, for both Huggies and Pampers, cost $29.99 not including tax. Amazon sells the Jumbo pack for $7.49, and $7.49x4 = $29.96. Since Amazon is in Washington, and I am in California, there is no sales tax. (Though I think technically in California you need to pay the tax for purchases made out-of-state if the products are used here... someone check on that.) Also, when you spend more than $25 on these products, you are eligible for the free super saver shipping. No shipping, no taxes, 4 cents cheaper, and more room in the car on Costco runs - Amazon wins. Just don't wait till the last minute to re-order. It'll take a few days to come.

Here's the breakdown. We have been using the Ultratrim, since that is all Costco carries. The Supreme is their high-end diaper with a "more comfotable fit". Note that Costco carries 1-2 whereas Amazon has both 1 and 2. Remember to buy four packs to get free shipping.

Huggies Ultratrimcountprice¢pd
Huggies Ultratrim Diapers, Jumbo Pack, Size 1, 8-14 Lbs., 56 ea - 1 pack22429.9613.4
Huggies Ultratrim Diapers, Jumbo Pack, Size 2, 12-18 Lbs., 48 ea - 1 pack19229.9615.6
Huggies Ultratrim Diapers, Jumbo Pack, Size 3, 16-28 Lbs., 40 ea - 1 pack16029.9618.7
Huggies Ultratrim Diapers, Jumbo Pack, Size 4, 22-37 Lbs., 34 ea - 1 pack13629.9622.0
Huggies Ultratrim Diapers, Jumbo Pack, Size 5, Over 27 Lbs., 30 ea - 1 pack12029.9625.0
Huggies Supremecountprice¢pd
Huggies Supreme Diapers, Jumbo Pack, Size 1, Up To 14 Lbs., 48 each - 1 pack19229.9615.6
Huggies Supreme Diapers, Jumbo Pack, Size 2, 12-18 Lbs., 42 ea - 1 pack16829.9617.8
Huggies Supreme Diapers, Jumbo Pack, Size 3, 16-28 Lbs., 36 ea - 1 pack14429.9620.8
Huggies Supreme Diapers, Jumbo Pack, Size 4, 22-37 Lbs., 31 ea - 1 pack 12429.9624.2
Huggies Supreme Diapers, Jumbo Pack, Size 5, Over 27 Lbs., 27 ea - 1 pack10829.9627.7
Huggies Convertibles Diaper-Pants, Size 5, Jumbo Pack (26 Pairs)10429.9632.6
Huggies Convertiblescountprice¢pd
Huggies Convertibles Diaper-Pants, Size 5, Jumbo Pack (26 Pairs)10429.9628.8
GoodNites Disposable Underpantscountprice¢pd
Goodnites Disposable Underpants, Jumbo Pack, Medium (17 Underpants)6829.9644.1
Huggies Pull-Upscountprice¢pd
Huggies Pull-Ups Training Pants, Jumbo Pack, Boys 2T-3T, 27 ea - 1 pack10829.9627.7
Huggies Pull-Ups Training Pants for Boys 3T-4T, Jumbo Pack (26 Pairs)10429.9628.8
Pull-Ups Training Pants, Jumbo Pack, Boys 4T-5T, 21 ea - 1 pack8429.9635.7
Huggies Pull-Ups Training Pants for Girls 2T-3T, Jumbo Pack (27 Pairs)10829.9627.7
Pull-Ups Training Pants, Jumbo Pack, Girls 3T-4T, 24 ea - 1 pack10429.9628.8
Huggies Pull-Ups Training Pants for Girls 4T-5T, Jumbo Pack (21 Pairs)8429.9635.7

Let me know if this is helpful. Here's the synopsis, Johnny:

Costco ($29.99+tax)

  • Can replenish the diaper stock in less than an hour (if you don't stop to eat samples and look at electronics)
  • Can stop to eat samples and look at electronics
  • In Santa Clara county, 8.25% more expensive due to sales tax
  • Have to drive to Costco and wait in line
  • Bulky, no place for plasma screen in car
  • Pain to unload from car

Amazon ($29.96)

  • Cheaper by 8.25%
  • Arrives at your door
  • Can purchase in pajamas
  • Look at electronics
  • No samples
  • Cannot wait until last minute

For the time being, if you by in excess of $50 worth of merchandise. Walgreens is actually cheaper. For size 3 UltraTrim, 60 ct., the sale price is $8.99. You would need to buy 360 at $53.94 (14.9¢pd). I'm not sure, but tax may be included. This courtesy of froogle.

April 20, 2004

TGI sushi - mmmm

Posted by torque at 11:12 PM | Comments (0) | TrackBack

Adsense Adwords analysis

Enoch, you might be interested in this one. GarageGames, makers of the Torque game engine, recently published an analysis of dollars made and spent via Google. They call it self-funded marketing. Nice. I quote, from Jeff Tunnell's .plan:

Ad Words (GG purchases the small text ads on search sites and other web sites, i.e. this costs GG).
288,594 Impressions
584 Click throughs to our Torque product page.
CTR (click through rate) = .2% (more below on this)
Money Spent: $170.32

Ad Sense (Google pays us to run ads based on click throughs)
297,822 Impressions
1,236 Click Throughs
.4% CTR
Money Earned: $164.90

This is not counting money from people that actually come to their site to buy stuff, and brand recognition. So the real numbers are actually even better than that. Tunnell also does an estimation of Google's take on the ad revenue which, by the T&C's, should probably not be published... but since it is out there,

"On a side note, we can derive Google´s royalty rate for running Adsense campaigns. Since GarageGames is the exact audience for ads that we run our Adwords campaign in, we can see that Google is taking a little more than 50% of the money. We have 584 click throughs for Adsense and have paid $170.32, for an average CPC of $.29. If we applied that CPC to the 1,236 CT´s from our Adsense ads, the gross amount collected from our ads would be 1,236*.29 = $358.44. Thus, the Google royalty is (358.44-164.90)/358.44 = 54%."

I have some issues with the analysis, but it is more detailed than anything I've seen thus far...

Posted by torque at 10:43 PM | Comments (0) | TrackBack

RFID file and book tracking

As is the case with most things that Ken and I come up with, it's done. Oh well, maybe we can focus on implementation.

On a more humorous note, read this and then this and then this. Yikes.

Posted by torque at 4:59 PM | Comments (0) | TrackBack


MIT's 6.033 had a design project last year on RFID that provides some good background on the technology. Among the interesting links is one on the FDA-approved VeriChip - a rice-sized RFID designed to be injected into humans. Actually, they weren't really approved, it was more that the FDA gave "written guidance" that the chip not be considered a "regulated medical device". It's actually kind of large, about the length of a dime (big piece of rice).

Posted by torque at 4:54 PM | Comments (0) | TrackBack

RFID for the masses

Ken and I have been talking for sometime on RFID apps. A very interesting article came up to day in the RFID Journal. Entitled "HP Designs Tracking System", it discusses HP's new RFID tracking system which consists of readily available hardware. The tracking system apparently cost less than $2000. Still not perfect for home use, the cost is certainly feasible for industrial use. To precisely locate the object, three small nodes (made by HP) use a combination of RF and ultrasound pulses to triangulate distance. The white paper, dated 2/23/04, gives a little more information about the project.

Posted by torque at 4:21 PM | Comments (0) | TrackBack

Replacing Java with Flash

Is it feasible? Christian Cantrell has an article entitled "Macromedia Flash Remoting Makes Macromedia Flash an Alternative to JSP and Applets" on the subject. I've played with using Flash as a web apps several years ago (for a learning tool) but haven't come back to it in several years. What are the pros and cons? Here's a nice calendar app - source here.

Posted by torque at 10:46 AM | Comments (0) | TrackBack

Open source useability

John Gruber's Ronco Spray-On Usability nteresting read on open source useability. He argues that for things to be really useable, they need to be closed and commercial because "successful open source software projects tend to be at the developer-level, not the end-user level. E.g., successful open source projects have programming interfaces, not user interfaces. Apache, Perl, Python, gcc, PHP, the various SQL databases."

Posted by torque at 9:52 AM | Comments (0) | TrackBack

April 19, 2004

Almost there...

I'm basically replicating an existing sample - but trying to understand things as I go along. Often it still seems that having code would make things much faster to understand. Labview is growing on me though.


Posted by torque at 6:13 PM | Comments (0) | TrackBack

Handling bad programs w.r.t. the 6430

I've been fiddling around with controlling the 6430 using Labview. From time-to-time, I write bad code, which causes all my other code not to work. Resetting the 6430 does not seem to make a difference, and the only solution seems to be to reboot the computer. This is very annoying. There must be a better way. The most frustrating part is when you don't know whether it is the code or if the GPIB card is stalling. I see the error a lot - it is the sign to reboot. Arrghhh.


Isn't that horrible? It's so bad I took it off the main page.

Posted by torque at 4:38 PM | Comments (1) | TrackBack

Xanga RSS

I'm not sure why it isn't widely publicized, but to get RSS from Xanga, all you need to do is to link to http://xanga.com/rss.aspx?user=<username>. Thanks Pretzel.

Posted by torque at 4:29 PM | Comments (9) | TrackBack

Bob Kolody versus Coca Cola

Fong sent me a very interesting set of articles on an impressively low-profile case involving Coca-Cola and an independent marketing consultant named Bob Kolody. It is a long read, and I'm by no means done (someone's gotta work around here...), but quite intriguing. Kolody alleged that Coca-Cola stole the concept used on the Classic Coke can from an illustration he presented to them in 1989, then proceeded to cover their tracks by fabricating documents to make it seem like it came from inside Coca-Cola. The case was eventually dismissed and petitions for rehearing denied. Keep in mind as you read the text that it mostly sides with Kolody.

Posted by torque at 2:34 PM | Comments (1) | TrackBack

A week of organic living

4colorsealJPG.jpgIn light of family discussions on pesticides, etc., I've been more conscious of what we eat. I found Diane Diconstanzo's article on "going organic" to be quite informative. My biggest concerns? Cost and living in paranoia. To learn more about what it means for food to be organic, check out the USDA's National Organic Program. Interestingly, the USDA "makes no claims that organically produced food is safer or more nutritious than conventionally produced food". There is a point there. One issue with organic food, sine there are no preservatives, is spoilage. In addition, since no ionizing radiation is used, bacteria may be more prevalent.

Posted by torque at 2:01 PM | Comments (0) | TrackBack

April 18, 2004

Coconut tapioca pudding

Tonight I'm making coconut tapioca pudding, we'll see how it goes. I'll be doing it in a Zojirushi NS-JCC18. The oringial recipe source is The Ultimate Rice Cooker Cookbook. For the record I used 2 cans of Roxy coconut milk from the Cupertino 99 Ranch and reduced the amount of sugar from 3/4 cup to 5/8. I also intend to top of the dessert with cubes of manila mangoes.

Posted by torque at 3:01 PM | Comments (4) | TrackBack

Bandwidth of TV channel

The bandwidth for a TV channel in the US is 6 MHz. For over-the-air channels, the channel 2 starts at 54 MHz. More information about the radio spectrum can be found on this (very dense) chart.

Posted by torque at 2:13 PM | Comments (1) | TrackBack

Solomon's pi

I stumbled on Jochen Katz's Pi in the Bible this morning. Very interesting. It addresses the value of pi (p) in I Kings 7:23, which, at first glance, appears to be 3, but, with gematria, can be shown to be 3 x 111/106. A more thorough treatment can be found in Tsaban and Garber's "On the Rabbinical Approximation of p".

Another view point, perhaps more classical, can be found here.

Posted by torque at 6:41 AM | Comments (0) | TrackBack

A9 update - tricky, tricky

beta-a9-logo.gifMy previous post on A9 was not completely accurate, it turns out the reason why I was able to look at book pages without logging in was that I had logged in already at A9. If you don't, the search is free, but once you click on the link, it'll ask you to sign in or create an Amazon account. Great marketing.

Posted by torque at 5:22 AM | Comments (3) | TrackBack

April 17, 2004

Cousin sea squirt and I

Several years ago, at the Joint Genome Institute in Walnut Creek, CA, scientists completely sequenced the sea squirt (Ciona intestinalis) genome [1]. These strange-looking critters are in fact, some of our closest spineless relatives. Their hearts and nervous system are simple versions of ours. While adults are more like spongy blobs, larvae look like tadpoles, with, interestingly, a rod of tissue stiffening their backs.

For you numerologists out there, the sea squirt genome has 160 million DNA letters, 20 times smaller than the human. These are organized into 16,000 genes, half as many as most vertebrates. Apparently we share about 80% of these.

[1] Dehal, P.et al. The draft genome of Ciona intestinalis: insights into chordate and vertebrate origins. Science, 298, 2157 - 2166, (2002).

Posted by torque at 10:41 PM | Comments (0)

Picnic Day 2004

Today, we went up to Davis for Picnic Day 2004. It was a blast! Highlights for me included

  • Spending time with my wife and kids, as well as two of my sisters
  • Shredded chicken sandwiches at the parking lot
  • A polish dog... mmmmm
  • Learning that the sea squirt is a distant cousin
  • Watching Linus play with hot wheels
  • Running though the rain
  • Sushi smorgasbord at Manna Korean Restaurant (622 3rd St, Davis, CA)

Posted by torque at 10:25 PM | Comments (0)

April 16, 2004

Mehr News and conspiracy theories

Over the last few days, several articles have been circulating on the net accusing the U.S. of surreptitously planting WMDs in southern Iraq. The two primary articles can be found below:

These reports originated from Mehr News in Tehran, the same agency which accused the U.S. of systematic sexual abuse against Iraqi citizens and setting up the website 'rape.com' to "celebrate their despicable acts'. Of course, from here, it is clear that this is completely bogus. The fact that this is a widely-read major newspaper in Iran is downright scary.

Posted by torque at 11:23 PM | Comments (159)

Real-time Margurite map!

After many months of talk, they finally released the site. GPS-powered, real-time Marguerite shuttle tracking. So cool. The whole things was put together by Avail Technologies an ofite in State College, PA specializing in Intelligent Transportation Systems (ITS) among other things. Admittedly, the flash intro is a bit much. Otherwise, it seems pretty solid.

There is such a thing as too much information. Thanks to this map, I missed the bus by about 30 seconds... twice.

Posted by torque at 5:12 PM | Comments (1)

4-wire sans connector

I realized that I could simply use one of the probe stations to act as a sense, since these were configured correctly. The results for the 18 MΩ resistor. About 25-30 seconds are necessary before the 2-wire values stop moving. The 4-wire values seem to take even longer, slowly creeping upwards. I'm speculating that the resistor may have some capacitance, causing its behavior over time to change. Should I let it sit until it stops moving, or should I record the first value right away? Tricky. I used a much smaller resistor (several kΩs) to discharge the large resistor right before recording a measurement for both 2-wire and 4-wire. This seems to always bring it back to about the same value.

measureR (MΩ)
2-wire, no OCOM17.6977
2-wire, with OCOM17.6971
4-wire, no OCOM17.6998
4-wire, with OCOM17.6986

Why would the 4-wire take so much longer to stabilize? What is the proper procedure?

Posted by torque at 2:38 PM | Comments (0)

If you had the power...

If you had the power and resources to completely redesign the world's socio-economic structure, given human nature, how would you do it? I started thinking about this after a heated debate on Bush's actions concerning Iraq.

Posted by torque at 2:01 PM | Comments (0)

Good morning God!


Posted by torque at 8:26 AM | Comments (3)

April 15, 2004

Triax and test equipment "accessories"

In my last post on the 6430, I realized that the triax-to-BNC converter was not hooked up properly for my application. Looking for triax online I inevitably ended up at Pomona Electronics, who also made my BNC to grabber cable, which I purchased for $13.99 at Fry's. Their Model 4725 & 5342 Triaxial BNC Male 2 & 3 Lug To Insulated Alligators Cable Assembly looks quite suspiciously like the corresponding Keithley part. Now where can I buy one? Whoa, it's $112.38 at Newark InOne. Per the 6430 data sheet, I would want the 3-lug part. They also have a BNC-to-triax connector, the 5300, but it is guard to shield.

It turns out that the 6430 data sheet includes a big list of accessories you can buy from Keithley. They offer the Model 7078-TRX-BNC Adapter, which is a 3-slot male triax to female BNC adapter used to connect a BNC cable to the triax input of the 6430. Now, unlike the Model 237-BNC-TRX Adapter (male BNC to 3-lug female triax), there is no mention that the guard is disconnected, so there is a chance that this is what we already have.

I found exactly what I was looking for at Probing Solutions - $166 for this tiny part. It's the one on the left, 102: Adapter, Male Triax/BNC Jack, Shield to Shield, not, as we have now, the Guard to Shield.

Posted by torque at 5:49 PM | Comments (6)

USDA's Pesticide data program

For well over decade, under the aegis of the Department of Agriculture, the Pesticide Data Program (PDP) has been testing commodities in the U.S. for pesticide residues. The PDP has tested over 50 different commodities including fresh/frozen/canned fruits, fruit juice, whole milk, grains, meats and water for over 290 different pesticides. Data are collected from a substantial number of states: California, Colorado, Florida, Maryland, Michigan, Mnnesota, Montana, New York, Ohio, Texas, Washington and Wisconsin.

How does it work? Close to the point of consumption, e.g., large chain store distribution centers, the commodities in question are randomly sampled in quanties of 3-5 pounds for fruit, 1 quart for fluids, and 1 pound for grains, poultry and beef. These are then shipped to a laboratory for analysis. The standard operating procedures are completely transparent. The detail provided on laboratory procedures is especially impressive, which makes sense, since both health and money are at stake. The resulting data, from nine State and two Federal laboratories, are stored in an electronic database in Washington, D.S. via a web front-end and, amazingly, available for download. Nice.

Posted by torque at 5:17 PM | Comments (0)

Amazon A9

beta-a9-logo.gifOf course, you knew it had to come. If Amazon can search through books, why not the web? A9 βeta is out. Powered, so far, by Google, Amazon extends the standard search results to include books, which is very, very nice for research. For some time now, I've been able using Amazon's Search Inside the Book feature - but for this one you don't even have to login. The only thing missing now are scientific journals. To save your searches, you can login using your Amazon account. Another cool thing? Alexa results follow major pages. There's been a lot of Amazon-Google collaboration of late...

Posted by torque at 4:36 PM | Comments (3)

Pagerank and redirect 301

Arrgh. So it turns out that the proper way of transferring a site is to do a redirect permanent, a.k.a., a redirect 301 using .htaccess. I did this, from my Stanford site to oncloud8 with one hitch. I had been using MT for sometime on oncloud8 prior to importing the old blogs. As a result, the index numbers are all mismatched - yikes. If you do a search on ebay automation, I come up first. But the link goes to a completely different subject. I'm not really sure how to fix this now, except perhaps to export and re-import. It's really a disaster.

I struggled for a little bit getting the redirect to work, I ended up putting an .htaccess in my root directory with "redirect 301 /~torque/blog http://torque.oncloud8.com". Note that the first reference, the original location, is relative to the domain, here, www.stanford.edu. That threw me off for a little bit.

Posted by torque at 1:07 PM | Comments (2)

Ohms, continued

To recap, I found an 18 MΩ resistor that I decided to use to scope out the Keithley 6430. I made two 2-wire measurements, with offset compensation (OCOM) disabled (17.7025 MΩ) and enabled (17.7084 MΩ). Next up, 4-wire measurements and other variations...

As a sanity check, I redid the two measurements (machine cold) from yesterday.

measureR (MΩ)
2-wire, no OCOM17.7057
2-wire, with OCOM17.7048

Not very encouraging. It is unclear how long it has to warm up before the readings are consistent? It may also be due to the temperature of the resistor. After about 5-10 minutes the OCOM measure is now 17.7056 MΩ. It has been about an hour now, here are the measurements.

measureR (MΩ)
2-wire, no OCOM17.7057
2-wire, with OCOM17.7047

Maybe I did something funny yesterday. Here's the setup for the 4-wire measurement:


I'm not sure why the diagram has the Sense LO going all the way back to the rear panel connector. Wouldn't it be sufficient to use the Sense LO from the pre-amp? Since I didn't have a banana plug cable handy, I used a triax to BNC followed by a BNC to clip leads. Something funny... I setup the four-wire measurement and am now getting 0.51274 MΩ. Weird. Without the sense wires, I get what I got before (whew... didn't break anything.) What went wrong here? Ok, I think I see the problem, I think it is the triax-to-coax connector. Instead of taking Sense HI and Sense LO out, it is taking Sense Hi and the shield.


The 6430 comes with one 6430-322-1A triax cable which is terminated with a triax connector on one end and booted alligator clips on the other end. Why just one? What I really would like is another one of these for the sense side.

On another note, I notice that whenever I hover around the measurement the reading gets noisy - static? capacitive-coupling? Be careful.

Posted by torque at 10:14 AM | Comments (2)

April 14, 2004

Boosting your pagerank

I just ported my blog from Stanford to oncloud8, and whoosh, my pagerank plummeted from 5/10 to 0/10. Granted, I just started this blog, but how can I boost the rank? At Stanford, I lucked out, since the pagerank was based on www.stanford.edu. That was really quite an advantage. Now there is Yahoo! Webrank. Now, who is fearless enough to download their toolbar. Google I trust, but Yahoo!? Do I need to hire SEO guns?

Getting started
Wyane at Blog Business World gives a whole slew of ways to market, what else, blogs. in particular, he suggests three ways of getting more incoming links - which we know are good.

  1. Link exchange requests at sites like Blogger Forum and Blogger Talk
  2. Link blogs you like, and then contact them by e-mail requesting links
  3. Post intelligent comments on other blogs (maybe they'll add you to their lists)

Posted by torque at 11:47 PM | Comments (0)

Hot dogs

Sonja sent me R. W. Apple Jr.'s superb article on hot dogs in Chicago a few days ago. It is from the NY Times, so it might not be available (at least not for free) in a few days. The photo of Polish dogs. by Peter Thompson, is really something. Even though I just had a huge dinner, I'm kinda craving the taste.

The article kicks of with Doug Soug's Hot Doug's. Sohn studied Culinary Arts at Kendall College. Hot Doug's has a motto - "There are no two finer words in the English language than encased meats." Of course, this kind of enthusiasm quickly suggests borderline fanaticism. A look on the menu confirms the gut feeling. From $1.50 "The Dog", a Chicago-style hot dog, to the $3.00 "The Raquel Welch" (might, mighty, mighty hot!), he's got just about everything you can think of. Today's special, the $5.50 "Buffalo Sausage with Chipotle Dijonnaise and Blue Cheese
". Next time I'm in Chicago, I'm there! For a good review, check out the Chicago Tribune. I wrote him to see if he would open one in the West Coast...

Other cool tidbits, no ketchup, as "true Chicagoan recoils from a ketchup-smeared hot dog the way your true New Yorker loathes melted Swiss cheese on a pastrami or corned beef sandwich." The article places the number of hot-dog stands in Chicago at greater than 1,800. In 2000, according to greatestcities.com, the population of Chicago sat at 2,896,016. So one hot-dog stand per ~1600 people. That seems pretty reasonable... the key to the hot-dog stands is the Vienna Beef Factory, which apparently is the major supplier of hot dogs in Chicago by far. Here's a link to a review of their deli.

Looking for the Factory I found the list of Best Chicago Hot Dogs (2002).

Ok, enough hot dogs.

Posted by torque at 11:03 PM | Comments (4)

Measuring Ohms

To get to know the 6430, I've decided to measure Ohms. According to 2-4 of the instruction manual, for the triax to alligator clip, red=HI, black=GUARD, and green=LO. Although I could have left LO floating, I connected it to the chassis ground. (I'll try the floating... later.)

For the two-wire configuration, per the diagram in the manual, SENSE is left open, and the resistor (the device under test or DUT) connected between HI and LO. GUARD is the same voltage as HI (2-6) - I left this disconnected.


There are four items to configure in resistance measurement:

  • SRC RDBK - source readback mode (ENABLE or DISABLE), and
For this first measurement, I set SOURCE to AUTO (CONFIG->Ω->SOURCE->AUTO) to make the device select its own test current. If you do not do this, it will give some wierd number - around 700 kΩ - because the source current is zero. I left everything at it's default (CABLE/ENABLE/DISABLE). Testing a resistor that Nick left on the table, I found it to be 1.00011-1.00013 MΩ with the value of the last digit fluctuating over time. Does it make sense? Unfortuantely the resistance value was encoded using 5 bands. Thanks to Sam Engström's graphically-nifty translator, I was able to decode it in a jiffy, 1 M&Ohm; with 1% tolerance. Good. The source current, Isrc, was 1.00000 μA and the compliance voltage limit, Cmpl, 2.10000 V.

Now, 1 MΩ was still kind of small, so I scrounged around and found a brown-brown-blue-gold resistor - 11 MΩ±5%. (Incidentally, in case you ever need them, html symbols found here.) Measurement? 11.2178 MΩ. Nice. I'll use this resistor for the remainder of my tests though it would be good if I could find something in the 100 MΩ range... I scrounged some more, and found a brown-gray-blue-gold resistor - 19 MΩ±5%. Measurement? 17.7025 MΩ. Ahh, I'll use this one.

Several quick tests. First of all, what does offset compensation do? It attempts to take out thermal EMF by measuring resistance (V/I) at a specific source level and then subtracting a resistance measurement made with the source set to zero. Result, 17.7084 MΩ. Interesting. Next step, 4-wire.

Posted by torque at 5:02 PM | Comments (0)


I really enjoyed Allan Gardyne's article "How to boost your AdSense revenue". Very interesting.

Posted by torque at 4:00 PM | Comments (0)

InfoUSA counts

Talked to Colby Lahun at InfoUSA (888.357.5340 x4160) about getting counts from their Sales Leads software. Each quarter, with the update, you are allowed 1000 exports, exports including cutting and pasting. You cannot cut and paste the count, it shows up in the title. InfoUSA charges $275 for the annual subscription, though you can get the software (most likely including the subscription) for less than $100 here.

Posted by torque at 11:57 AM | Comments (0)

April 13, 2004

Soy milk

Thanks to Wil and Gloria's generosity, we made soy milk tonight with our Vita Mix blender. It worked out quite well - no sieve needed. The key is time... you have to blend it for quite a while - around 15 minutes so that the soy cooks, otherwise, it has kind of an astringent smell to it. You know you are done when it smells better.

Posted by torque at 8:48 PM | Comments (0)

Palo Alto Junior Museum and Zoo

This morning we all went to Palo Alto Junior Museum and Zoo. It was a lot of fun. They have a new engineering oriented exhibit that is quite well done. I was particularly impressed by their rendition of Archimedes' water screw.

Posted by torque at 8:46 PM | Comments (0)

VI curve

I managed to get the 6430 to take a VI curve using the following code:

:*SRE 1;
followed by
and a wait period. I have several things in mind for this device. I would like to:
  1. Test input current for various amplifiers, and on the Softsens sensors,
  2. Measure the DC resistance for various electrode combinations, and
  3. Measure the impedance between 0-100Hz for various numbers of pins in my pin-electrode.

Probably the easiest first test is to do the resistance. That will also give me a chance to measure noise in the measurement. According to IEC 60601-1-4, for non-cardiac, floating ground applications, the limit is 100 μA DC and 10 μAC.

Things to do:

  1. Figure out how to get raw data from the machine
  2. Get labview to plot my data
  3. The grounding configuration...

Posted by torque at 4:37 PM | Comments (2)

April 9, 2004

Getting labview working

The GPIB board finally came in. At the moment, we are running a copy of Labview 7 Evaluation, though the real one should come in a week or so. Through Keithley, you can download the 6430 BETA LabVIEW ver. 5.X driver for Windows, which, when unzipped, contains a library of Labview VIs for the Keithley 6430.


Make sure that the communication mode on the 6430 is set on GPIB, 488.1 (not SCPI) and click on "Keithley 6430 One-Shot Measure?". Run the instrument by clicking on the white go arrow, and you should see something like this:


That's great. The next step is to build our own continuous acquisition. Here's the block diagram.


First, do a Save As so that we don't write over the original.

Posted by torque at 3:22 PM | Comments (4)

April 8, 2004

IEC 60601-1-4

I need to find out what the international limits are on injecting current into the body between DC-100 Hz. If I can get a wider band of frequencies that would be even sweeter. Unfortunately the IEC 60601-1-4 cost big bucks, and I can't find it in any library. Can anyone out there help? The cheapest I've found is around $150. What's up with that?

Jackpot. Meca Associates gives a checklist that has a condensed data 60601-1 for free. That's really something. Kudos.

More stuff:

  • Some hints can be found here, but don't really address my question.
  • A thread in Google groups mentions that the maximum leakage under IEC 60601-1 for cardiac applications is something like μA.
  • Another (from 1999) states that the Federal Regs say leakage current on a device that could come in contact with a patient cannot exceed 300 μA"
  • I found a draft standard of UL 60601-1. While it isn't the real thing, it might be good enough to give me some numbers to work with. The real thing is sold by UL for a whopping $550. That's really annoying. How can they sell a standard that everyone has to follow? You have to pay to be in compliance AND you have to pay to find out what you have to comply to. To be fair, someone had to write this all up, but still...

Posted by torque at 4:48 PM | Comments (0)

April 1, 2004

Keithley 6430 notes...

It says, on page 2-4,

Whenever the Remote PreAmp is connected to the mainframe, adhere to the following rules to achieve best performance:
  • Do not use INPUT/OUTPUT HI and 4-WIRE SENSE HI on the mainframe. Access these terminals at the Remote PreAmp. Hmm, that seems straight-forward. but just HI?
  • Access input/output low at the Remote PreAmp or at the mainframe, but not both. What about the SENSE LO? Test circuit common should be tied to one point to avoid ground loops which could generate error currents. Fair enough...
  • Do not use guard from the mainframe and the Remote PreAmp at the same time. Use one or the other.

Posted by torque at 1:43 PM | Comments (1)