IEEE Consultants' Network of Long Island

Insects and Yellow Light - John Dunn, Consultant, Ambertec, P.E., P.C.

Some years ago, I was listening to "Crockett's Victory Garden" and the man spoke of reducing a white fly infestation on a caller's plant. He said to take a yellow Prestone anti-freeze container, cover it all over with a thin layer of petroleum jelly and set that container down next to the infested plant. The theory was that the white flies would be attracted to the yellow plastic and get stuck in the petroleum jelly coating.

Then, the next thing I notice is that so-called "bug lights" for use outdoors emit yellow light which is not supposed to attract insects to one's front door.

Can somebody tell me what's going on here? Are some insects able to see yellow and others not? Is there a significant spectral difference between the transmitted yellow light of the bulb versus the apparent yellow of the Prestone container's retransmission of incident white light or daylight?

SAN BRUNO AFTERMATH—Carl Schwab

The government is pursuing its investigations to try to find what was the cause of the San Bruno explosion September 9, 2010. Recall it was a massive explosion that dug a huge crater some 50' x 110'. To date what has emerged is a major scandal about the records keeping of PG&E, Pacific Gas and Electric.

PG&E is a huge corporation and has some 48,000 miles of NG pipelines in Northern California. PG&E currently has some 300 people working to computerize about 1.25 million records dating back more than 70 years and located at more than 3 dozen locations. The cross-referencing is a nightmare. At specific contention is about 150 miles of 30" high pressure main about which the records are completely unreliable.

 

The Violet Ray - John Dunn, Consultant, Ambertec, P.E., P.C.

There was a medical quackery perpetrator called The Master Electric Company Chicago whose goodies are discussed on line at http://www.radiolaguy.com/VioletRay.htm . Somebody once gave me one of those Master Violet Ray devices and I still have it:   

 

Capillary Pumping - Dick LaRosa

Figure that the solar heated evaporator surface is 10 cm (4 inches) above the sea surface. In the last post, a 0.1 mm (100 micro-meter) diameter capillary was found to lift seawater 29.1 cm. We only have to lift it 10 cm, so we have (19.1 cm)(1024 kg/m3)(9.8 m/s2) pressure available to overcome viscous friction. Poiseuille's formula tells us that the quantity of water pumped per second is proportional to the fourth power of the radius times the pressure difference divided by (viscosity)(length). Surface tension and viscosity of sea water are about the same as the respective values for fresh water. I used 1.0E(-6) m2/s for the kinematic viscosity. Multiply that by the density to get the viscosity used in the denominator of Poiseuille's formula. The result is that a single capillary tube transports 4.59E(-11) m3/s.

Rise Times of Voltage Multipliers - John Dunn, Consultant, Ambertec, P.E., P.C.

A voltage multiplier does not achieve its full output voltage instantaneously upon the application of its AC input voltage. The half-wave doubler shown below and analyzed by the recursive differential equation method, illustrates the point.

The ratio of the two capacitors of this circuit, the ratio of C1 to C2 affects the DC output rise time, but there is always some rise time slowness. 

CELL BALANCING BASICS:-- Carl Schwab

The question of cell balancing really comes to the surface when we are considering multi-cellular battery packs and when we are considering chemistries based on Lithium. The reason for the interest in Lithium is its high specific energy density i.e. for a given weight it stores the highest Joule level or watt-hrs/kilogram. The drawback with Lithium is its sensitivity to over-charging or over-discharging. Either condition causes permanent loss of capability for the cell. The writers experience is with the hobby industry and interest in electric powered vehicles.

SOME BACKGROUND: For the electric vehicle industry a few different chemistries have been used. Specifically lightweight lead-acid, nickel-iron, nickel cadmium and nickel-metal hydride. All these chemistries can withstand moderate over-charging and even over-discharging to the point of cell voltage reversal. Experience by Toyota (and others) has shown by keeping the SOC, State Of Charge, within a 20% to 80% range the batteries will yield long life and support peak loads such as by acceleration and fast recharges by dynamic braking. The negative point about these chemistries is weight-----compared to Lithium they are nearly 2 to 1 heavier.

Phase Shifter - John Dunn, Consultant, Ambertec, P.E., P.C.

The following is a general plan for producing two sinusoidal signals whose relative phase can be adjusted arbitrarily between zero and 180°.

Starting with two equal amplitude sinusoids in quadrature with each other, sitting 90° out of phase, we assign one of them to be a "cosine wave" and the other one to be a "sine wave" from which we can produce two new sinusoids whose phase angle can be arbitrarily adjusted as desired.

 

Forgiveness - John Dunn, Consultant, Ambertec, P.E., P.C.

There is a really great application note AN-202 from Analog Devices that can be found on line at http://www.analog.com/static/imported-files/application_notes/135208865AN-202.pdf . Following the rail voltage bypassing example as shown in Figure 8 of that note, I set up a low-noise amplifier's op-amp rail voltage bypass capacitors as follows:

 

Learning Stuff - Dick LaRosa

I have to figure out whether sea water can be lifted and distributed over the solar-heated evaporator panels using capillary action. The Hausmann and Slack text that I used in 1942 was on loan to our grandson, so I went to a local public library  and searched "capillary action" and "surface tension". Nothing came up so I searched "physics". When only a juvenile book and an encyclopedia showed up I went to the stacks and found some books on college physics. There seems to be a semantic problem that excludes college physics from just-plain-old physics, but I did not pursue that distraction because a book by Serway and Faughn had what I needed. Other books on the shelf and the physics encyclopedia made no mention of the subject. A Van Nostrand Scientific Encyclopedia had some material that seemed incomprehensible and incorrect to me.

 

Current Pumps - John Dunn, Consultant, Ambertec, P.E., P.C.

It's always handy to have a few constant-current injection circuits in one's bag of tricks, so here are just a few that should be at least considered when the occasion calls for one:

 
The junction FET circuit was a little troublesome at first. It wanted to oscillate. That's why the 0.01 µF is there to quiet it down. The response time was a little slow, but for the application at hand, that didn't matter.