jump to navigation

A shocking experience December 19, 2010

Posted by mareserinitatis in electromagnetics, engineering, physics.
Tags: , , ,
trackback

Shortly after I began doing some research on electrostatic discharge (ESD), I was having a discussion with some engineers about my work and how I was doing it. I got a couple of surprising comments.

The first engineer was actually a chemical engineer, and when I explained that part of my work involved monitoring static buildup on manufacturing equipment, this person asked me what this had to do with ESD.

The second question was frustrating: how can you have ESD unless you have a path to ground? The engineer in this case was an electrical engineer…and this is an example of a little knowledge being a dangerous thing.

I explained a bit before about triboelectric charging. Basically, when you rub two objects together, one will tend to want keep electrons and the other may be more likely to give them up. The result is that after you’re done rubbing these two objects, one will have given up electrons and become positively charged while the other took as many electrons as it could handle, resulting in that object being negatively charged.

If your electrons stay on an insulator, it’s probably not a huge problem. They aren’t terribly mobile that way. The real problem comes when this charge is somehow transferred to a conducting object. A really simple example is taking off your polyester-lined winter jacket while wearing a nice wool sweater. If that doesn’t generate charge, I can’t tell you what will. Anyway, it’d be nice if that charge just stayed on your sweater. It doesn’t: it gets on your body, which will behave like a conductor. When you reach your hand out to touch the closet door, *ZAP!*.

So the first engineer was partially right: a buildup of static electricity does not imply with 100% certainty that ESD can or will occur. However, if you prevent charge from building up on an object, even if it’s an insulator, then you’ll not have the opportunity to fry any sensitive electronics should it somehow get transferred elsewhere.

In the example above, you have an ESD event because you touched a door, which was presumably grounded. Interestingly enough, that doesn’t have to be the case. What you really need to cause an ESD event is for one object to be at a higher electrical potential than the other object. For instance, sometimes people get shocked after getting out of their cars in the winter. The car, you’ll notice, is not grounded: it is insulated from the ground by the tires, so electricity can’t flow to ground. However, a car is large enough that it can spread any charge it acquires fairly thin, leaving it at a very low potential. When you get out of the car, you touch the side, and you feel a shock. However, it’s not because the car is grounded: you transferred static electricity from your body to the car, which is at a lower potential.

The electrons on a conductor are going to repel each other as much as possible, and as soon as they see that they can go someplace else that has less electrons, they’re going to blow the joint. If the potential between the two objects is very great, then you get a large current, and the resulting discharge may be visible and possibly painful. If the potential is small, then the current may be minimal, smaller than can be felt or seen by the human body. However, when you’re dealing with electronics, even a tiny discharge can be damaging.

I’ve not worried about the first engineer’s question too much because I assumed his expertise relied on different knowledge. I assumed the second engineer should have known better. On the other hand, I realize that most engineers, when introduced to the concept of ESD on a technical level, are shown discharge models that almost always indicate that the current flows from a person (or machine) to the electronics and out to ground. I really wish they’d change those diagrams because it isn’t always true.

I always wished I’d had the opportunity to go up behind the second engineer with an ESD gun and zap him with it. That way, when he turned around and got mad at me for shocking him, I could tell him that it wasn’t possible because he wasn’t grounded (in more ways than one). Not that I’d ever really do it, but the thought crossed my mind more than once.

Comments»

1. Charles J Gervasi - December 19, 2010

I model a person as a 33pF high-voltage cap with one side connected to your body and the other dside to ground. That’s just touching a terminal can sometimes act as an RF ground. It’s why you can get a static shock wearing shoes. Your voltage relative to ground can be very high, so you can store a decent amount of charge.

EEs just need a model. We see the underlying physics as a lower layer of abstraction that is not germane to the problem at hand.

Regarding the direction of the current in an ESD event, it depends on whether you’re using positive or negative current convention, so it really doesn’t matter.

Once I freaked out a young admin person by touching her arm to equalize our charges before handing her a board that really should have been in an ESD bag. My mind was strictly on Q=CV, my imagination of loosely-bound electrons equalizing through water w/ salt and other electrolyte solutes, and how to protect those tiny layers of Si oxide in modern ICs; but after I did it I realized how Aspergian that method of ESD protection was.

I still do it, though, b/c nothing is worse than handing someone a board and getting shock.

mareserinitatis - December 20, 2010

:-) I am always imagining what electrons are doing. I know EEs like their models, but there is a lot of insight to be gained by thinking about the physical behavior. (In fact, I have a hard time thinking about models…)

2. Dave Cuthbert - December 19, 2010

ARRGH. Revoke that EE’s license. He or she clearly does not understand what ground means.

Ground is just an arbitrary reference point which we designate as 0 volts. So, yes, in an ESD discharge event, I could assign one of the nodes to be the ground and have the current flow to it.

Electrical panels in buildings do have a wire which is run to a rod stuck into the earth and/or a water pipe which runs underground, and this potential is taken as the ground reference (and the origin of the term). But it’s by no means the absolute ground reference for every circuit. (In fact, earth-ground potentials can vary considerably over geography and time.)

Chris Gammell - December 20, 2010

My favorite way to explain this to young engineers is: “How do you define ‘ground’ when designing electronics for a satellite?”

mareserinitatis - December 20, 2010

I really wish they’d use the term “return path” rather than ground, though. I think that makes it a little easier to see that the ground potential is somewhat arbitrary. When you hear or see ground, zero volts is what pops into my head.

Fluxor - December 20, 2010

Only those working with E&M or RF likes to use “return path”. Then there’s the concepts of AC ground vs. DC ground vs. virtual ground.

mareserinitatis - December 20, 2010

The ones working emag and with RF are the only ones who count, right? :-D

3. Mike - December 20, 2010

It’s also very common in the EMC world, where you are talking about unintended current flows – the return path is where the current goes, not necessarily where ground is on the schematics.

4. Open Laboratory 2011 – submissions so far | A Blog Around The Clock - February 9, 2011

[...] Faraday’s Cage is where you put Schroedinger’s Cat: A shocking experience [...]

5. Open Laboratory 2011 – submissions so far | A Blog Around The Clock - February 28, 2011

[...] Cage is where you put Schroedinger’s Cat: A shocking experience Faraday’s Cage is where you put Schroedinger’s Cat: Moonscape Reminder: Owens [...]

6. Dee - July 28, 2011

Is it possible for the wireless technology, it’s energy to be attracted to our bodies and perhaps be responsible for the fact that more of population is experiencing ESD (wireless’s static magnetic fields?) In the last 10 years, I have had a ESD build up on my body that I have transferred to my vehicle too many times too count. About 5-6 years ago those shocks became more intense and I had to start availing myself of a brass key to make first contact with my car What is happening in our enviroments that someone like me is daily becoming the higher electrical potential???? 20 years ago I might of experiencing this 2-3 times a year. I can experience this 3-5 times on a daily basis Would appreciate any guidance or advice of situations that might be capable of causing our bodies to have perhaps an excess of ESD occuring.

mareserinitatis - July 28, 2011

Initial guess would be that you’re wearing a lot more synthetic fibers. Likewise, upholstery materials are also made of more synthetics. (Or maybe you’re wearing cotton and the upholstery in your car is synthetic, making the problem worse.) These are notorious for developing a charge and exacerbating ESD problems. So, if anything it’s probably what you’re wearing that’s causing the problem. Also, if you’ve moved to a drier climate or are in a climate cycle where it’s gotten drier, that makes ESD a lot worse, too.

7. Dee - July 29, 2011

But aren’t our electrical grids also responsible for adding ES that is attracted to our bodies??? Our electrical grids also emit non-ionizing radiation, right?

mareserinitatis - July 29, 2011

Electrical lines are fairly well shielded. They aren’t going to generate enough potential on your body to do much. Local build up of static electricity is usually much stronger.

8. Dee - July 30, 2011

Yes electrical lines are fairly well shielded but the areas where they connect, that equipment is not, right? The high voltage lines, the substations, the power poles, the audible noise, etc.
But the build up on our bodies, one of the known sources is known to come from our power lines, as it is classified as non-ionizing radiation in studies, right??

mareserinitatis - July 31, 2011

I think you’re confusing the presence of an electromagnetic field when ‘static buildup’.

Our bodies are conductors…poor conductors, but conductors nonetheless. When we stand in the presence of a field, this means that electrons will flow from one side of our body to the other to negate that field. However, being poor conductors, it doesn’t do this very well. And with the fields as weak as they are, it’s not going to cause a huge change.

All the field can do is ‘rearrange’ any charge that is already on our body, it can’t put more there. Fields don’t make electrons, just move them around. Any charge that occurs on your body is likely from fabrics on your body rubbing against other materials and generating charge. You would be surprised how much charge that can generate! Discharge occurs when you touch something that will conduct the buildup away from your body.

Therefore, if you feel you’re being strongly affected by ESD, you are either wearing more fabrics or sitting on things that are likely to generate charge (consult a triboelectric chart give you an idea of what they may be) or touching metal more often. Of course, there is even the possibility that you are eating more salty foods as the electrolytes would make you a better conductor!

9. Charles J Gervasi - July 30, 2011

I agree the emissions from power lines are non-ionizing radiation, but that does not mean large voltages will be developed on nearby objects. You’re talking about voltages being developed between one object and another. I don’t see why the presence of an EM field, even a 60 Hz one would drive charge from one object to another. I’d be open to learning a mechanism for that that I don’t know. Right now, though, I cannot see an EM field building up a voltage on the human body with respect to another object.

10. Dee - August 2, 2011

mareserinitatis In science, I thought the concept was their never is just one answer. Yes your explanation is as good as the next but it leaves out of the equation other environmental manipulations factors that have entered our lifes besides the fabric of our clothes and the salt in our diets.
Seems to me, most likely you can say similiar being a fact of our environments being bombarded with constant wireless streams pushing it’s energy through our atmosphere of gases, inducing friction considering all the gases it has to push aside to get here. I mean, think about all that wireless activity and the mass of friction it must be infusing into our environments at the rate of millions, billions, and trillions of cycles per second over and over again and on top of it is a vibrational energy field. Vibrational energy fields tend to do a lot of rubbing together too. But thanks for your take on it Appreciate you taking the time

mareserinitatis - August 2, 2011

In science, I thought the concept was their never is just one answer.

No, in science, one must be able to validate experimentally one’s theory. There absolutely can be one answer.

All of what I told you has been *experimentally verified*, and what I described is basically behavior that is explained and which one does experiments to verify in most calculus-based freshman or sophomore physics courses. So on top of just ‘an explanation’, we also have mathematical model, known as Maxwell’s equations, that describes how electromagnetic fields behave. It doesn’t matter if the field comes from the sun or the cosmos or the wifi next door: they behave in essentially the same way. And, in fact, you still receive more radiation from the sun than you ever will from your wifi.

As an example, you say wireless fields induce friction in gases, but we have a definite mathematical explanation of what friction is: it’s the loss of kinematic motion that a surface experiences as it moves against another surface. Fields don’t have mass and therefore do not have a surface – they can’t experience friction.

It’s hard to work with fields as we have intuitive notions of how things work based on how we see things move around us. A lot of that intuition doesn’t hold up because fields are made of photons which have no mass. A photon moving through space behaves very differently from a baseball moving through space.

Learning physics (and science in general) is about questioning our assumptions about how things work. I’d strongly encourage you to keep asking questions, but you have to go into it with an open mind and realize that things *don’t* behave the way we think they should…but that doesn’t mean how this stuff works is a total mystery, either.

Charles J Gervasi - August 2, 2011

There has been a recent increase in the amount of data that can be sent over the radio, but my impression is there has not been a signficant increase in field strength the ave person is exposed to. We’ve found ways to push closer to the theoretical limit of how much information we can transmit per unit time and per unit energy. This makes it seem like we are exposed to more RF energy. I suspect if you took a broadband antenna to a major city 50 years ago and measured the power of the spectral components used for communications, it wouldn’t be radically different.

Regarding the claim about RF delivering energy to the air: The absorption coefficient of air varies with frequency but at communications frequencies it’s low. My 25W ham radio and 0.05W WiFi AP are thermally trivial compared to the light bulbs in my lab or the heat from my body’s metabolic processes.

It seems like if there were significant athermal effects from RF, they would have appeared with the first broadcasts of hundreds of kW. I’m always open to new evidence though.

11. Dee - August 2, 2011

Charles Not a significant increase that avg person is exposed to?? I am getting quite the different impression as it is not about RF but being exposed to microwaves. Somehow, I think quite the opposite would most likely be truer as they hadn’t yet advanced this form of radiate energy of wireless microwaves yet 50 years ago. RF delivering energy to the air?? hmmm doesn’t broadband use the technology of microwave and infrared frequencys????

This makes it seem like we are exposed to more RF energy I suspect if you took a broadband antenna to a major city 50 years ago and measured the power of the spectral components used for communications, it wouldn’t be radically different.

Charles J Gervasi - August 2, 2011

Microwave is a subset of RF, radio waves of frequencies over 800MHz (exact boundary is arbitrary and subject to debate.) Radar systems with outputs in the kW existed well over 1,000MHz existed over 50 years ago. UHF TV stations up to 750MHz, also in the kW range, become common around 50 years ago. Now, though, cities have thousands of 1,300MHz mobile phone cell sites in the 1W range and a 0.05W Wi-Fi transciver in every laptop and phone. So the RF environment is clearly different from 50 years ago. (I didn’t start playing radio until 1986.)

Today when I take a spectrum analyzer to the ISM bands and point the antenna downtown Madison, I get bursts from frequency hoppers in the -60dBm range. Most of the Wi-Fi is harder to detect on an analyzer b/c of its low power spectral density – BW = 20MHz and received power is in the -70dBm range. I agree if I went back in time an looked at the ISM bands, or any microwave bands, I’d detect less energy. But what I get right now isn’t all that far above the noise floor of a good receiver.

Broadband is a colloquial term usually meaning “high data rate”. It does not have anything to do with wireless RF. It’s easier to get high data rates over a cable than wireless

12. Dee - August 3, 2011

I am no expert here, but if you are going to talk about radar in this day and age vs 50 yrs ago, shouldn’t you be honest and admit their are radar systems in the 300+ GHz range? That today it could be 300,000 MHz not some little ole 1,000 MHz and the technology seems to just keep advancing every 18 months. 4,5, 6 GHZ range and it just keeps going as they keep surpassing themselves away from little ole 1300 MHz.
Or perhaps you don’t know how far advanced radar is now into the 100-300 + GHZ range???
kW and MHz in the same conversion sentence? A watt converting to a wavelength frequency?? Really??

roteno - August 3, 2011

Moore’s law doesn’t apply to RF. Discussing power densities over frequency is very appropriate in this discussion. Many design/regulatory trades are made when settling on a frequency band. Higher frequency != “better”. Maybe some RF coursework is in order here.

13. Charles J Gervasi - August 3, 2011

I mention power and frequency in the same sentence because the absorption (and maybe unknown effects you suggest) vary with frequency.

I’m trying to say the radio spectrum in major cities hasn’t changed that much, but it occurred to me last night that even 10 years ago I wouldn’t have spent most of the day with my hand right next to a 2.4GHZ 0.05W transmitter. I don’t think that’s relevant to anything, but I’m questioning my claim that the spectrum hasn’t changed radically. It certainly would have changed some if the antenna spent the day on my hands.

I can’t explain issues like the interaction of radio waves on water, air, the human body unless you study EM fields and communications systems. If you did that, mareserinitatis could explain way better because she has more than my hand-waving trial-and-error understanding of electromagnetism. I probably have more tinkering why-isn’t-this-radio-working experience. I sense you have vague fears based on the fact that technology is changing rapidly.

I really think if you took EM and communications and their prereqs at a university (not necessarily working toward any degree) you would be able to congeal your concerns into cogent hypotheses and test them.

14. Dee - August 3, 2011

50 years ago we didn’t have hundreds of millions of cell phones transmitting in the gigahertz range nor had we advanced to satellite cable. 50 years ago we didn’t have satellite radio that avails of gigahertz (2 GHz) as that was only advanced in the last 15 years. 50 years ago major cities were experiencing the AM/FM bands of kilohertz and 100 mehahertz
So yeah, major cities have experienced a major change of the radio spectrum compared to 50 years ago.

mareserinitatis - August 4, 2011

The spectrum probably was a lot different years ago…in some areas. However, if anything, the power being transmitted has decreased, especially with the conversion to things like digital TV. Digital requires lower power, and so, in some ways, the amount of ambient electromagnetic energy may potentially have been higher in the past.

The point you fail to realize, however, is that these fields are SO low once you move away from the antenna compared to local effects like triboelectric charging. You can generate fields in the KV region with a good triboelectric charge, no where near what you’d experience standing in an average city and absorbing ambient EM. Pulling a piece of scotch tape off paper has been shown to produce xrays! So you can’t just look at what has the most power…you have to also look at the scale at which that power is working. So if you’re worried about ESD, looking at Wifi means you’re simply barking up the wrong tree.

I would agree with the commentors above: if you really are that concerned, I think some formal coursework in emag would really assuage your concerns.

15. Dee - August 4, 2011

ESD magnetism and ability to attract is not just a function of friction.
To beam 1000 of miles through the atmosphere, thru multiple layers of different composition of the atmosphere, thru jetstreams, thru weather systems, etc., well that is one huge scale at which those powers need gains in which to work. They advanced the technology before they understood it’s potential harm and most likely they would have to downplay it’s harm, because it is radiation. It has to be more likely high than on the low side to have enough radiate energy working that it is going to make it all the way to Earth probably losing some of it’s power along the way so by the time it reaches Earth it is transferred into a low power. Common sense has to wonder how much of that energy trade off affects Earth’s eco system’s and not just us living systems. Also got to think about what type of holes is it punching in our ozone that the rate of damage is faster than the rate of repair can keep up. For every action their is a reaction. Their was a rush to switch to digital. Got to wonder why and who it benefits the most. The technology has exploded and more has never equaled less in anyone’s book. Radiation is radiation whether it comes in small doses or large doses.

Charles J Gervasi - August 5, 2011

@Dee I don’t understand what claims you’re making, so I can’t really comment on it. Regarding why we switched to digital, you could a class in Random Processes (Noise) and DSP. You probably have to take a discrete-time systems class before DSP. To understand why it happened when it did, you could take a class on solid-state fabrication, but you don’t need that; you just need to know transistors are getting faster. (I mentioned before you need EM fields and a communications class.) I don’t mean this to be snarky. After a year or two of part-time classes, you could have a lot of answers and not need to wonder.

The stuff you’re saying sounds like my vague fears about the food supply. We have tinkered with genetics and developed techniques that grow food for a larger world population than imaginable in history using small amounts of land. We’re also eating less diversity and more of a few foods that work well with new processing methods, methods different from cooking on top of heat source in a kitchen which has been used for centuries. I’ve got to wonder if this puts us at risk for some plague knocking out a big chunk of the food supply and how this food affects our bodies. I really do wonder. But I don’t know anything about it because I’ve never studied it or worked in agriculture or food processing.

If you learned how to program PLCs or something like that, which I have heard is easy, they might pay for you to take communications classes. Parts of the classes are dry, but parts make you feel like someone in the audience when they showed experimental wireless telegraphs transmitting across a stage. Tinkering with antennas in the Wisconsin elements sometimes feels like Marconi on Signal Hill in Canada. Practical working MIMO is as amazing to me as transatlantic wireless must have been.

16. Dee - August 4, 2011

Wireless the precautionary principle was ignored even though they were aware it was a less lethal form of radiation. Others can spin EM, but more can never equal less.
Technology comes first, health comes 2nd. Power and greed are a 1-2 combination that don’t exactly have high standards of moral compass’s.
Bottom line, it has to have some form of harmful effects upon the environment because it is a heat source. That is something you known is true.

elements of precautionary principle
1. When we have reasonable suspicion of harm
2. When there is scientific uncertainty
3. We then have a duty to take action to prevent harm

17. Dee - August 6, 2011

The radiate energy from satellites is higher nearer its source and weakens as it gets further away from it’s source. This concept apply’s to all known electric and magnetic field strengths, right? Is that vague to what you were taught? Food???

static is not just an event of 2 objects rubbing together, their are also static magnetic fields which also comes from manmade sources, right?

Wherever there is electricity, there are also electric and magnetic fields, invisible lines of force created by the electric charges. Electric fields result from the strength of the charge while magnetic fields result from the motion of the charge,

http://www.greenfacts.org/en/power-lines/l-3/power-lines-1.htm#3p0

California Department of Health Services and
the Public Health Institute of California “Electric and Magnetic Fields Program” (2000

magnetic fields can be strong or weak, be of high frequency (radio waves) or low frequency (powerline waves), have sudden increases (“transients”) or a constant strength, consist of one pure frequency or a single dominant frequency with some distortion of other higher frequencies (“harmonics”).

Sources with high voltage produce strong electric fields, while sources with strong currents produce strong magnetic fields. The strength of both electric and magnetic fields weakens with increasing distance from the source (table 1). Magnetic field strength falls off more rapidly with distance from “point” sources such as appliances than from “line” sources (powerlines). The magnetic field is down to “background” level supposed to be no greater than that found in nature) 3-4 feet from an appliance, while it reaches background level around 60-200 feet from a distribution line and 300-1000 feet from a transmission line. Fields and currents that occur at the same place can interact to strengthen or weaken the total effect.
Hence, the strength of the fields depends not only on the distance of the source but also the distance and location of other nearby sources.

18. Dee - August 6, 2011

Iarc, International Agency for Research on Cancer

This volume evaluates possible carcinogenic hazards from exposures to static and extremely low frequency (ELF) electric and magnetic fields. It is the first of two IARC Monographs volumes on various kinds of non-ionizing radiation. Extremely low frequency (ELF) magnetic field exposures result from proximity to electric power transmission lines, household wiring, and electric appliances and are in addition to the exposure that results from the earth’s magnetic field. Overall, extremely low frequency magnetic
fields were evaluated as possibly carcinogenic to humans (Group 2B). Static magnetic fields and static and extremely low frequency electric fields could not be classified as to carcinogenicity to humans (Group 3).

http://books.google.com/books/about/Non_ionizing_Radiation.html?id=zBxDML96BmMC

19. mareserinitatis - August 7, 2011

Dee,
You’re taking a lot of things and putting them together. EM is not necessarily a heat source. The cancer classification was put as such because *ONE* study found that it may be linked to an incredibly rare form of brain cancer, but the results were not conclusive. All other studies don’t show any evidence of a link to cancer. If wireless really were causing cancer, the amount of people with brain cancer would have skyrocketed over the past decade…but that’s not what we see.

Honestly, I’m willing to answer questions, but you’re fear mongering on a topic about which you know very little and can barely articulate a coherent statement. If you want to ask questions and learn about it, fine. I’m willing to help. If you’re here to argue about something you obviously don’t understand, this becomes a waste of my time.

20. Dee - August 8, 2011

EM excites sensory pathways and that excitation can lead to interference of our cell signalling process’s, encoding damage. Damaged DNA has long known to have capacity to cause cells to proliferate, including cancer cells. But since the majority of studies PURPOSELY leave out of the equation how NON-IONIZING RADIATION (EM) has capacity to excite sensory pathways that has nothing to do with heat THEY GUARANTEE a loophole so that their studies can continue to be INCONCLUSIVE.

Honestly, I am not fear mongering. I am seeking the truth about a technology that was allowed to fast forward into our lives without knowing the potential long term health effects on the population.
And truth be told their are multiple studies emerging linking bond breaks within the DNA to EM of wireless and not a JUST ONE STUDY of reasoning of why and how this damage is proliferating cancer cells to not be suppressed as our immune systems are being compromised. See Dr Henry Lai I have admitted I am only a layperson, but you are inferring your opinion as FACT and it would seem that you really haven’t taken time to do much research on the subject yourself and you also know little about it as well.
And if you took the time to do some research you would find that brain tumors are on a steady rise and that should be indication of something in our environments that is responsible for that rise in brain tumors nevermind other cancers.
When the rate of harm is coming in faster than the rate of DNA repair can keep up, this has a tendency to lead to prolonged states of stress, chronic diseases and the ultimate of cancer.

Both ELF n RF have been shown to cause cells to generate stress proteins, a universal sign of distress in plant, animal and human cells

http://www.bioinitiative.org/report/docs/section_17.pdf

This is a 28 page pdf report

. KEY SCIENTIFIC EVIDENCE
I

Exposure to electromagnetic fields (EMF) has been linked to a variety of adverse health
outcomes. The health endpoints that have been reported to be associated with ELF
and/or RF include childhood leukemia, adult brain tumors, childhood brain tumors,
genotoxic effects (DNA damage and micronucleation), neurological effects and
neurodegenerative disease, immune system disregulation, allergic and inflammatory
responses, breast cancer in men and women, miscarriage and some cardiovascular effects.
Effects are not specifically segregated for ELF or RF, since many overlapping exposures
occur in daily life; and because this is an artificial division based on frequencies as
defined in physics that has little bearing on the biological effects. Both ELF and RF, for
example have been shown to cause cells to generate stress proteins, a universal sign of
distress in plant, animal and human cells.

The number of people exposed to elevated levels of EMF has been estimated in various
studies, and there is general agreement among them. In the United States, few people
have chronic or prolonged exposures over 4 mG (0.4 µT) (Kheifets et al, 2005b). Section
20 has information on average residential and occupational ELF levels. The highest
4 mG (> 0.4 µT). Many people have daily
exposure category in most all studies is >
exposures to ELF in various ways, some of them up to several hundred milligauss for
short periods of time, but relatively few people with the exception of some occupational
workers habitually experience ELF exposures greater than 1-2 mG (0.2 – 0.3 µT – App.
20-A).

The exposure of children to EMF has not been studied extensively; in fact, the FCC standards for exposure to radiofrequency radiation are based on the height, weight and stature of a 6-foot tall man, not scaled to children or adults of smaller stature. They do
not take into account the unique susceptibility of growing children to exposures

pg 3
————————-

(SCENIHR, 2007; Jarosinska and Gee, 2007), nor are there studies of particular
relevance to children.

Differences in exposure patterns between infants, children and adults; 2) special
susceptibilities of infants and children to the effects of EMF; and 3) interactions between
chemical contaminants and EMF are lacking; as are studies on chronic exposure for both
children and adults. There is reason to believe that children may be more susceptible to
the effects of EMF exposure since they are growing, their rate of cellular activity and
division is more rapid, and they may be more at risk for DNA damage and subsequent
cancers. Growth and development of the central nervous system is still occurring well
into the teenage years so that neurological changes may be of great importance to normal development, cognition, learning, and behavior. Prenatal exposure to EMF have been identified as possible risk factor for childhood leukemia. Children are largely unable to remove themselves from exposures to harmful substances in their environments. Their
exposure is involuntary.

Like second-hand smoke, EMF is a complex mixture, where different frequencies, intensities, durations of exposure(s), modulation, waveform and other factors is known to produce variable effects. Many years of scientific study has produced substantial
evidence that EMF may be considered to be both carcinogenic and neurotoxic.
The weight of evidence is discussed in this report, including epidemiological evidence and studies on laboratory animals.

Relative risk estimates associated with some of these endpoints are small and the disease is fairly rare (for childhood leukemia, for example), For other diseases, the risk estimates are small but the diseases are common and EMF exposures at levels associated with increased risks are widespread and chronic so the overall public health impacts may be very large.
pg 4

——-
KNOWLEDGE IS POWER
Again I am not fear mongering, I am just seeking the truth trying to find if any of you engineers have any idea about the over abundant energy that is nowadays indulating our environment possibly creating a more harsh enviroment for all living systems.

Honestly I am not here to argue, but I am here to try and learn. But thank you for your time even thought you didn’t understand much about what we are being faced with nowadays with EM. Peace

21. Charles J Gervasi - September 6, 2011

This discussion of health risks of RF prompted me to read about the topic and write a post about it: http://bit.ly/RFHealth

Those concerned about RF have such a broad hypothesis almost any results that future studies reveal any athermal interaction between radio waves and the human body can be considered a hit. This makes it easy to deploy post hoc rationalization, special pleading, and the Texas Sharpshooter fallacy to whatever data is collected.

They are right that we cannot completely rule out some unknown effects of microwaves on the human body.

If the hypothesis is microwaves in certain frequencies, duty cycles, spectral densities, coupling mechanisms, etc that are too weak to provide noticeable heating can still have some unspecified health effects, I would not be completely shocked to see that hypothesis proven true.

22. Dee - September 7, 2011

Your article is misleading. Non-ionizing radiation has long been known that it has the capacity to stimulate and excite signal pathways that has nothing to do with heat. Our electrical grid’s are considered non-ionizing radiation also. It is not like the term electrostatic discharge came from the science of clothes friction.
A tactile vibrational field has the ability to stimulate other sensory pathways like hair follicles not to mention it’s modulated and pulsed frequencys that might also affect our auditory pathways and overstimulate that signalling pathway as well all without the use of heat but with the use of stimulating our own bodies inner process’s of friction. Over stimulated signalling pathways = DNA damage
I might only be a layperson, but I just don’t understand why so many would leave that important fact out of their hypothesis equations.

Cherish - September 7, 2011

Dee, what you’re saying makes no sense. Friction is the conversion of kinetic energy to heat. What you’re saying is that vibrations are converted to heat in the body, exactly the opposite of the point you’re trying to make.

I think you’re putting together words you don’t understand with meanings that you don’t understand.

23. Dee - September 7, 2011

The public isn’t always given the truth and nothing but the truth when it comes to marketing a commodity as conflicts of interests seem to have already set the tone of what is likely to be reported or not reported.

Interactions between radiofrequencies signals and living organisms
Source of funding in experimental studies of mobile phone use on health:

http://www.sciencedirect.com/science/article/pii/S1631070510001465

Available online 30 December 2010.

Abstract
A previous review showed that among 59 studies published in 1995–2005, industry-funded studies were least likely to report effects of controlled exposure to mobile phone radiation on health-related outcomes. We updated literature searches in 2005–2009 and extracted data on funding, conflicts of interest and results. Of 75 additional studies 12% were industry-funded, 44% had public and 19% mixed funding; funding was unclear in 25%. Previous findings were confirmed: industry-sponsored studies were least likely to report results suggesting effects.
Interestingly, the proportion of studies indicating effects declined in 1995–2009, regardless of funding source. Source of funding and conflicts of interest are important in this field of research.

Here we see where the mindset of influence was leading. No wonder we don’t get straight answers anymore, especially when the job involves marketing a commodity. Got to sing the company’s praises or most likely many would be out of a job.

2004
Abstract
This article connects issues of funding ethics to freedom of research, a set of principles shielding against influences interfering with scientists’ obligation to seek truth. Arrays of interests relate to the search for knowledge and affect policies of research funding. Conflicting concerns demand alignment, also taking ethical questions into account. Sources of ethical concerns in research funding are reviewed: meeting quality standards, securing qualifications, satisfying budgetary demands, dealing with risks, observing principles of independent decision making, utilizing yet controlling personal ambitions are some elements. The relation between basic and applied research, and the tension between the tradition of seeking knowledge for its own sake and concern with the marketability of results are discussed and related to differences between funding from public and corporate sources. Issues of scientists’ influence on research funding are considered in view of the need for qualified research evaluation and the turf interests of scientists.

http://www.sciencedirect.com/science/article/pii/B0080430767001844

In conclusion, the entry points to the changing role of research and suggests an increased tendency to view research results as market commodities.

24. Charles J Gervasi - September 7, 2011

If you go to the article and click Add a Comment, it will take you to a registration page which only asks a few questions. I and the other electronics people can answer the questions about the electronics side. The topic of health effects of radio waves is different from the topic of ESD anyway.

You’re saying that modern science is little more than “singing the praises” of those who fund the research. If a scientist finds a breakthrough in this area and resists the temptation to go Pons-and-Fleishmann, her career would not suffer.

The one quote you sent said all studies regardless of patronage are converging on the null hypothesis, i.e. less and less likely to find an effect. That is what we would expect if there really were no effect.

25. Dee - September 7, 2011

Cherish Please don’t go putting words into my mouth. I am not saying that. I think you probably don’t know much about your own bodys chemical and electrical signalling pathways. Studies are emerging that a heat shock protein might be doing some of the damage that induces DNA into prolonged states of stress.
Tactile vibrational energy fields have the ability to stimulate a cell signalling response. All it takes is an environmental stimulus to excite a sensory pathway.
OVERSTIMULATION = DNA DAMAGE
Heat is not the problem.

An environmental stimulus causes a response in an organism when specialized structures, receptors, are excited. Excitations are conducted by nerves to effectors which act to adapt the organism to the changed conditions of the environment

http://www.answers.com/topic/brain

Dee, what you’re saying makes no sense. Friction is the conversion of kinetic energy to heat. What you’re saying is that vibrations are converted to heat in the body, exactly the opposite of the point you’re trying to make.

I think you’re putting together words you don’t understand with meanings that you don’t understand.

26. Dee - September 7, 2011

Charles Since when has money stopped being capable of control??

and actually Charles that 2010 study made no mention of a NULL HYPOTHESIS.

The one quote you sent said all studies regardless of patronage are converging on the null hypothesis

What the 2010 study did infer was:
Interestingly, the proportion of studies indicating effects declined in 1995–2009, regardless of funding
source. Source of funding and conflicts of interest are important in this field of research.

Interactions between radiofrequencies signals and living organisms
Source of funding in experimental studies of mobile phone use on health:

http://www.sciencedirect.com/science/article/pii/S1631070510001465

Available online 30 December 2010.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Follow

Get every new post delivered to your Inbox.

Join 1,265 other followers

%d bloggers like this: