IEEE Consultants' Network of Long Island

Satellite Recon - John Dunn, Consultant, Ambertec, P.E., P.C.

Just how good are satellite reconnaissance photographs? Maybe this will give us a clue.

This is a satellite photograph of my home. Those two white dots are a pair of vents over my dining room's roof. Each vent is an aluminum square, approximately twelve inches on a side.

With this picture having been taken from shall we say two hundred miles up (1,056,000 feet), the one foot dimension would indicate an angular resolution of arcsin(1/1,056,000) which is 0.000054257 degrees or approximately 54.257 microdegrees.

Is NIST Getting Better? - John Dunn, Consultant, Ambertec, P.E., P.C.

Remember the old saw that "Practice makes perfect."?  

I wonder if these two frames from http://www.time.gov/timezone.cgi?Eastern/d/-5/java  are any kind of evidence of that: 

Oh, what a difference seven years makes. Maybe by the year 2018, we'll see an accuracy measured in milliseconds

Belt Driven Lathes - John Dunn, Consultant Ambertec, P.E., P.C.

I took a trip down Memory Lane the other day. The journey began at

http://www.youtube.com/watch?v=ebDMh6pAlN8&feature=related

and continued at

http://www.youtube.com/watch?v=2sSXPC2AL_o  

which is where these belt driven lathe images came from:  

LED Spectra - John Dunn, Consultant, Ambertec, P.E., P.C.

The illustration below shows some light source spectral distributions that were presented by Cree, Inc. at an LED seminar in March of 2010. Clearly (no pun intended.), the contours of intensity versus wavelength differ profoundly from one light source versus another.

 

Flashlight Batteries and Bulbs - John Dunn, Consultant, Ambertec, P.E., P.C.

It's a small thing perhaps that so many flashlights become unreliable with use, but it's been a pet peeve of mine for quite some time.

Many flashlights depend on the tip of the bulb to make contact with the positive end of the upper flashlight cell as sketched below on the left. This works okay for a while, but eventually, the metal of the bulb's tip deforms by flattening out while the positive tip of the flashlight cell also deforms by becoming concave as sketched below on the right.

Then the flashlight doesn't stay lit as I hold it. I have to shake a little it to get light or I have to twist the light bezel back and forth a little bit.

Train Whistles - John Dunn, Consultant, Ambertec, P.E., P.C.

I was listening to an interview on Public Radio earlier today where the topic was acoustic environments,

In the course of that dialog, a comment about train whistles was offered which I have not been able to independently confirm, but which very much caught my attention.

The interviewee stated that Canadian train whistles are required by law to be triple-toned as an E-flat minor triad. American train whistles can be single-toned, but Canadian whistles must meet the more demanding requirement.  

I just had to check this out.  

HOME NG USAGE/FRACKING—Carl Schwab

First just to give an update on how the oil-togas conversions have gone on Longwood Drive, where the write lives My conversion started operation on January 13,2009, so we have completed approximately 3 years operation. We have been pleased, as have the others that did the conversions at the same time. The writer has had no problems of any kind and with oil at $3.00+ per gallon; my gas costs are about ½ that oil would have been. My NG is billed an a monthly basis over the entire year and my past year has been $121 per month for the year or $1452 for the year. Before conversion to NG the same boiler used about 890 gallons per year so the savings are substantial.

 From a national policy standpoint, it is clear that this country should make maximum usage of NG for not only home heating use but also for electric power generation (replacing coal usage) and for commercial building heating. Oil usage, particularly oils such as #2 domestic are needed for transportation, both land and air.

Driveway Lightning - John Dunn, Consultant, Ambertec, P.E., P.C.

One spring, a thunderstorm came through here during which this tremendous lightning bolt was unleashed.

I think the lightning strike must have been right in my driveway. It was broad daylight, but the flash of light was vivid. The sound of the thunderclap was immediate and LOUD!! The living room television lost its cool and started reprogramming itself for automatic tuning to the available TV channels.

Later on, I found that the cable modem for my PC had gone to that grand e-cycling place in the sky.

Wave Glider Unmanned Maritime Vehicle - Dick LaRosa

The Wave Glider is made by Liquid Robotics. It consists of a surface float 208 cm x 60 cm and a submerged glider 191 cm long with 6 wings having a wing span of 107 cm. The float and glider are connected by a 7-meter tether. The surface float is subjected to wave motion, while the glider is below much of the wave action. The wings are pivoted. When the float rises, the tether pulls the wings into a positive angle of attack. When the wings are pulled upward, the glider moves forward. The tether has some thickness, but it appears to be flexible and can only exert tension between the float and glider.  When the glider descends into the trough of a wave, I am guessing that the tether slackens and springs force the wings into a negative angle of attack so that they move forward as the glider descends due to gravity.

Architectural Columns - John Dunn, Consultant Ambertec, P.E., P.C.

I once read about this architect who had a project underway where a large open area was to be provided with vertical columns. He decided that the usual circular column cross section was not esthetically pleasing and that he wanted to use something else, but what that something else would be was elusive. Therefore, he sought the assistance of a consultant, in this case, a professor at a nearby university.

The professor came up with something right away.

The equation of a circle is x² + y² = Radius² for which the exponent of each variable is "2". The professor said to instead use the equation x^1.5 + y^1.5 = Radius^1.5 for which the cross section looks like this: