Richard Clark wrote:
On Fri, 05 Sep 2008 14:00:52 -0400, Jon Mcleod
wrote:

A few weeks ago, I asked about generating an 140kHz electric field
across a leaf, part of a bio-med lab. Thanks for the answers. But it
turns out I misread the roster and was in the wrong group.

What I ACTUALLY NEED to do is generate a 100kHz electric field, at
1v/cm, across a T-Bone steak, to measure whether it retards or
accelerates decomposition over time. The hypothesis is that the e-field
retards growth of certain bacteria inside the meat.

A pretty shabby hypothesis.

By design, we have not been instructed exactly how to construct the
methods and apparatus. I have at my disposal a function generator and
various amplifiers.

It is a gross oversimplification to just connect one wire to one end of
the steak, and another wire at the other end, and apply 20V RMS across a
20cm steak to generate 1V/cm?

Yes it is a gross oversimplification. What are your controls?

Thanks. Sorry about the idiot questions.

Hi Jon,

It has been historically proven that the e-fields of 60 Hz current
across the ribs of convicts, over time (about several minutes)
seriously accelerates decomposition. Sterilization would naturally
follow too answering the point about bacteria growth. Between those
two obvious observations, it would seem you have a conflicting agenda.
The hypothesis you are testing seems to want to simultaneously
challenge and support longstanding evidence through shifting frequency
without actually specifying how MUCH current should be applied. Thus
the hypothesis devolves to: "How does frequency enter into what has
already been observed?"

Let me point out that this, too, already has longstanding evidence of
doing pretty much offering the same outcome; and the state, for the
sake of economy, has long since abandoned the hypothesis of performing
executions with 100KHz electric chairs.

To put it simply, you have to many unstated and unfulfilled variables
to call your proposal a hypothesis.

73's
Richard Clark, KB7QHC

Mr. Clark,

The control is another steak is similar size from the same grocery
packaging, placed in a second apparatus that is not powered.

The idea is that a certain frequencies of low-voltage e-fields inhibit
cellular mitosis.

The professor saw an article in Science magazine about treating cancer
with these fields, and decided it would be a nice lab activity for his
students to observe other effects with this type of field.

http://www.rife.de/files/disruption_...eplication.pdf

Since generating an e-field in "meat" or "plant material" is not so
easy, this is part of the assignment. We need to figure it out and then
fully describe it in our methods section. The leaf people are using
high-voltage insulated wires. With "meat", which is larger, I don't
think this will work. I am wondering if I can use a low-voltage direct
connection.

My problem is that our group is weak on electromagnetism. They have
been floundering, and now I am floundering with them. I have some
ideas, but ideas are best vetted through those with PRACTICAL
experience, which you guys seem to have. I have also wasted almost 2
weeks by sitting in the wrong group. OK I am an idiot in terms of BOTH
electromagnetism and reading directions.

Bottom line: I need to generate a 1V/cm field across a t-bone steak.
Merit or no merit (this is college). Does anyone have any place I might
look on line, or any book I might buy, or any advice on how I might
accomplish this?

Thank you.

"Jon Mcleod" wrote in message
m...
Richard Clark wrote:
On Fri, 05 Sep 2008 14:00:52 -0400, Jon Mcleod
wrote:

A few weeks ago, I asked about generating an 140kHz electric field
across a leaf, part of a bio-med lab. Thanks for the answers. But it
turns out I misread the roster and was in the wrong group.

What I ACTUALLY NEED to do is generate a 100kHz electric field, at
1v/cm, across a T-Bone steak, to measure whether it retards or
accelerates decomposition over time. The hypothesis is that the e-field
retards growth of certain bacteria inside the meat.

A pretty shabby hypothesis.

By design, we have not been instructed exactly how to construct the
methods and apparatus. I have at my disposal a function generator and
various amplifiers.

It is a gross oversimplification to just connect one wire to one end of
the steak, and another wire at the other end, and apply 20V RMS across a
20cm steak to generate 1V/cm?

Yes it is a gross oversimplification. What are your controls?

Thanks. Sorry about the idiot questions.

Hi Jon,

It has been historically proven that the e-fields of 60 Hz current
across the ribs of convicts, over time (about several minutes)
seriously accelerates decomposition. Sterilization would naturally
follow too answering the point about bacteria growth. Between those
two obvious observations, it would seem you have a conflicting agenda.
The hypothesis you are testing seems to want to simultaneously
challenge and support longstanding evidence through shifting frequency
without actually specifying how MUCH current should be applied. Thus
the hypothesis devolves to: "How does frequency enter into what has
already been observed?" Let me point out that this, too, already has
longstanding evidence of
doing pretty much offering the same outcome; and the state, for the
sake of economy, has long since abandoned the hypothesis of performing
executions with 100KHz electric chairs.

To put it simply, you have to many unstated and unfulfilled variables
to call your proposal a hypothesis.

73's
Richard Clark, KB7QHC

Mr. Clark,

The control is another steak is similar size from the same grocery
packaging, placed in a second apparatus that is not powered.

The idea is that a certain frequencies of low-voltage e-fields inhibit
cellular mitosis.

The professor saw an article in Science magazine about treating cancer
with these fields, and decided it would be a nice lab activity for his
students to observe other effects with this type of field.

http://www.rife.de/files/disruption_...eplication.pdf

Since generating an e-field in "meat" or "plant material" is not so easy,
this is part of the assignment. We need to figure it out and then fully
describe it in our methods section. The leaf people are using
high-voltage insulated wires. With "meat", which is larger, I don't think
this will work. I am wondering if I can use a low-voltage direct
connection.

My problem is that our group is weak on electromagnetism. They have been
floundering, and now I am floundering with them. I have some ideas, but
ideas are best vetted through those with PRACTICAL experience, which you
guys seem to have. I have also wasted almost 2 weeks by sitting in the
wrong group. OK I am an idiot in terms of BOTH electromagnetism and
reading directions.

Bottom line: I need to generate a 1V/cm field across a t-bone steak. Merit
or no merit (this is college). Does anyone have any place I might look on
line, or any book I might buy, or any advice on how I might accomplish
this?

Thank you.

the problem is, do you want the field 'inside' the meat, or in the air
around the meat? The problem is made harder because the steak is not only a
dielectric material, which changes the magnitude of the field, but is also
moderately conductive, which essentially shorts out the field. also, the
properties depend on the direction of the field... you might want to see if
your library has this article:
http://ieeexplore.ieee.org/xpl/freea...rnumber=300250 . personally
i would probably go the other way and suspend the meat on an insulating net
horizontally and put a plate above and below it that are bigger than the
steak. it is much easier to generate a uniform field between large parallel
conductive plates than with wires... as a first approximation make the
plates about double the largest dimension of the steak. it may be
acceptible to set the steak on one of the plates (sterilize it first) and
just suspend the other one above it.

Dave wrote:

the problem is, do you want the field 'inside' the meat, or in the air
around the meat? The problem is made harder because the steak is not only a
dielectric material, which changes the magnitude of the field, but is also
moderately conductive, which essentially shorts out the field. also, the
properties depend on the direction of the field... you might want to see if
your library has this article:
http://ieeexplore.ieee.org/xpl/freea...rnumber=300250 . personally
i would probably go the other way and suspend the meat on an insulating net
horizontally and put a plate above and below it that are bigger than the
steak. it is much easier to generate a uniform field between large parallel
conductive plates than with wires... as a first approximation make the
plates about double the largest dimension of the steak. it may be
acceptible to set the steak on one of the plates (sterilize it first) and
just suspend the other one above it.

Thank you! In hindsight, obviously applying a field top to bottom will
be easier than side-to-side!

I need to research it, but I should be able to calculate the voltage
required to generate the 1v/cm field in the steak if I know the
dielectric constant of the "meat"...

One question, what if the plates both touch the steak and I use a
smaller voltage? I guess since steak is conductive, keeping the plates
at a 1V/cm potential may actually sink a lot of current through the
steak and cook it after all.

On Fri, 05 Sep 2008 15:11:20 -0400, Jon Mcleod
wrote:

I need to research it, but I should be able to calculate the voltage
required to generate the 1v/cm field in the steak if I know the
dielectric constant of the "meat"...

Hi Jon,

The dielectric constant of anything is a sidebar, or distraction,
simply because you don't know the dc of the original work's cells
either. In all probability they are the same, but this is unnecessary
information.

More to the matter is where you derive 1V/cm from the original work's
application of an average of 550V (nearly 3 orders greater) to 1mm gap
(exactly 1 order smaller). Your 1V is off by nearly 4 orders of
magnitude.

Again, if you were a convict and they let you set the voltage DOWN by
4 orders of magnitude, you might ask for a cool drink while the threw
the switch and waited several hours for your execution. They may have
to suspend it on account of darkness until the next dawn.

73's
Richard Clark, KB7QHC

Following my post, I read your source material closer to then ammend
my statements, interleaved below:

On Fri, 05 Sep 2008 12:27:57 -0700, Richard Clark
wrote:

On Fri, 05 Sep 2008 15:11:20 -0400, Jon Mcleod
wrote:

I need to research it, but I should be able to calculate the voltage
required to generate the 1v/cm field in the steak if I know the
dielectric constant of the "meat"...

Hi Jon,

The dielectric constant of anything is a sidebar, or distraction,
simply because you don't know the dc of the original work's cells
either. In all probability they are the same, but this is unnecessary
information.

In fact, they do report the dielectric constant, and as I speculated,
nearly identical to that of steak (or seawater for that matter).

More to the matter is where you derive 1V/cm from the original work's
application of an average of 550V (nearly 3 orders greater) to 1mm gap
(exactly 1 order smaller). Your 1V is off by nearly 4 orders of
magnitude.

In fact, they do report 1V/cm.
The electric field intensity was mapped within the cell, based on
the amplitude (1 V/cm), frequency (100 kHz) and waveform (sine) of
the electric field applied to the cell culture.

Unfortunately their reference for this was
11. Volakis JL, Chatterjee A, Kempel LC. Finite element method
electromagnetics: antennas, microwave circuits, and scattering
applications.
which cannot be applied to a situation where the wavelength of
excitation is 3000 meters and the gap is one thousandth meter. The
calculation of 1V/cm based upon the application of an average of 550V
across a 1mm gap flies in the face of credulity.

However, and again confounding their use of power amplifier to deliver
1 V/cm in the near field, there is the report:
The electric field intensity in the culture medium was measured by
means of a probe, consisting of two (0.25 mm in diameter)
insulated wires with exposed tips 0.5 mm apart, that was dipped in
the culture medium. The wires were connected to a high-input
impedance differential amplifier that translated the waveform
amplitude into a calibrated steady voltage that was digitally
recorded. Field intensities throughout the manuscript are
expressed in peak voltage amplitude per centimeter (V/cm).

Care was taken to eliminate any pickup from the field outside the
culture medium. Continuous field monitoring could also be made by
measuring the potential drop across a 100 Ohm resistor placed in
series with one of the field generating wires.

This last statement lacks data about what voltage was observed and
says nothing of the contribution of field's interaction with the leads
going to it to measure the voltage across them.

I can understand your desire to simply shove your function generator's
output directly into a steak. It is a choice that is tantilizingly
teased as an option given this report of 1 V/cm. It also raises the
curious aversion of the authors from performing the same test and
removing the absurd complexity of amplifiers and remote senors.
Afterall, 1 V/cm is trivial to obtain, demands no external
amplification, and whose level can be monitored from the function
generator itself.

All of this (in concert with missing data and no computation shown)
suggests a problematic correlation of results (which are inarguable)
to field strength.

Again, science would say replicate the conditions and observe if the
results follow. You can make your own correlations. All things being
practical, the application of an average of 550V across a 1mm gap
demands a better reporting of a finding of 1 V/cm in the sample.

73's
Richard Clark, KB7QHC

"Jon Mcleod" wrote in message
...
Dave wrote:

the problem is, do you want the field 'inside' the meat, or in the air
around the meat? The problem is made harder because the steak is not
only a dielectric material, which changes the magnitude of the field, but
is also moderately conductive, which essentially shorts out the field.
also, the properties depend on the direction of the field... you might
want to see if your library has this article:
http://ieeexplore.ieee.org/xpl/freea...rnumber=300250 .
personally i would probably go the other way and suspend the meat on an
insulating net horizontally and put a plate above and below it that are
bigger than the steak. it is much easier to generate a uniform field
between large parallel conductive plates than with wires... as a first
approximation make the plates about double the largest dimension of the
steak. it may be acceptible to set the steak on one of the plates
(sterilize it first) and just suspend the other one above it.

Thank you! In hindsight, obviously applying a field top to bottom will be
easier than side-to-side!

I need to research it, but I should be able to calculate the voltage
required to generate the 1v/cm field in the steak if I know the dielectric
constant of the "meat"...

One question, what if the plates both touch the steak and I use a smaller
voltage? I guess since steak is conductive, keeping the plates at a 1V/cm
potential may actually sink a lot of current through the steak and cook it
after all.

yes, that would be much harder and may result in cooking.. better to keep an
air gap.

One question, what if the plates both touch the steak and I use a
smaller voltage? I guess since steak is conductive, keeping the plates
at a 1V/cm potential may actually sink a lot of current through the
steak and cook it after all.

Sure, you can have the plates touch the meat. If it's 1cm thick, put a
volt across it, and you're done.

As you point out, though, if you put that field on the meat itself
(whether by direct contact, or because it's suspended between two plates
with air in the middle), current will flow, and heat will be dissipated.
Your exercise is to figure out how much, and how hot it gets.

Assume the thermal capacity is the same as water.
I'd assume the conductivity is about the same as sea water (60 mS/cm) as
a start.

On Fri, 05 Sep 2008 18:53:53 GMT, "Dave" wrote:

The problem is made harder because the steak is not only a
dielectric material, which changes the magnitude of the field, but is also
moderately conductive, which essentially shorts out the field.

Hi Jon, through Dave,

Let's examine what is offered above, and the fault in a large T-Bone.

The original work was performed with an average of 550V across a gap
of 1mm which contained a sample of cells. Those cells, too, shorted
out the voltage, but across a shorter distance.

Most function generators will only source several volts at best, let's
call it 5.5V to simplify comparisons. We replicate the field
arrangement with a 10cM portion of steak. When we revisit the field
strength, we will find it has plunged from the normalized 550,000V/m
of the original work to the now feeble 55V/m or 4 orders of magnitude
lower field of your suggested work.

It would follow from the original author's thesis that your efforts
will show 4 orders of magnitude less results. Call it zero. There's
no point in doing it without replicating the fields as specified in
the original.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
On Fri, 05 Sep 2008 18:53:53 GMT, "Dave" wrote:

The problem is made harder because the steak is not only a
dielectric material, which changes the magnitude of the field, but is also
moderately conductive, which essentially shorts out the field.

Hi Jon, through Dave,

Let's examine what is offered above, and the fault in a large T-Bone.

The original work was performed with an average of 550V across a gap
of 1mm which contained a sample of cells. Those cells, too, shorted
out the voltage, but across a shorter distance.

Most function generators will only source several volts at best, let's
call it 5.5V to simplify comparisons. We replicate the field
arrangement with a 10cM portion of steak. When we revisit the field
strength, we will find it has plunged from the normalized 550,000V/m
of the original work to the now feeble 55V/m or 4 orders of magnitude
lower field of your suggested work.

It would follow from the original author's thesis that your efforts
will show 4 orders of magnitude less results. Call it zero. There's
no point in doing it without replicating the fields as specified in
the original.

Mr. Clark,

In the introduction, they describe, "In the present study we show for
the first time, to our knowledge, that very low-intensity (
2 V/cm),
intermediate-frequency (100–300kHz), alternating electric fields induced
by insulated electrodes have specific inhibitory effects on dividing
cells in culture."

The novocure dude is talking about 2 V/cm, and the prof here is talking
about 1V/cm. I don't need to duplicate this experiment, I need to
immerse a T-Bone into a 1V/cm, 100kHz e-field. I appreciate your help
so much, but I don't understand where 550,000V/m is coming from???

On Fri, 05 Sep 2008 15:41:15 -0400, Jon Mcleod
wrote:
The novocure dude is talking about 2 V/cm, and the prof here is talking
about 1V/cm. I don't need to duplicate this experiment, I need to
immerse a T-Bone into a 1V/cm, 100kHz e-field. I appreciate your help
so much, but I don't understand where 550,000V/m is coming from???

Hi Jon,

Take 550V (the average of their amplifier's 300-800V capacity) and
place it across 1mm. How many volts per meter?

Consider the claim and specification of 1V/cm. How many volts per
meter?

How many volts will you need to obtain 1V/cm across a T-Bone steak
measuring 20 centimeters?

If you can solve one, you can solve them all.

Where did the missing voltage go? This is a simple series impedance
relationship that is linear with distance. To obtain 1V/cm from the
author's source demands that there is considerable impedance isolating
the sample from the excitation probes. This could be accomplished if
there were a huge air gap between the first excitation probe and the
cells' culture, and perhaps a corresponding huge air gap on the other
side of the cell culture towards the second excitation probe. The
ratio of impedances would be 550,000/10. The sum of both air gaps'
impedance would have to exceed the cell culture's impedance by this
ratio.

This is possible, but the report is obscure to that possibility. The
introduction of field measurement probes would be exceedingly
disturbing to the balance of impedances too. The diameters of those
probes consume half the gap within which the cell culture resides, and
lay in exceedingly close proximity to the excitation probes! The
probes themselves present more mass and area than the cell culture.

The claims are specific, but all the evidence points to the authors
having convinced themselves of a very problematic measurement. They
are, afterall, no more versed in the art of antenna math and finite
element modeling than you are. They got numbers to be sure, and
performed what every student would recognize as "plug-n-chug."

However, you are more interested in the results than the claims. Your
assignment, as I understand it, is to investigate what results follow
from your own variation of their work. Unless you are trying to also
validate the correlations to fields, which I seriously doubt you could
do, and would be suspect through direct attachment (as it does not
conform to the original); then I would suggest you think smaller gap
(not a T-Bone), up the voltage (as offered), and measure bacterial
activity.

Or, in your own terms:
What I ACTUALLY NEED to do is generate a 100kHz electric field, at
1v/cm, across a T-Bone steak, to measure whether it retards or
accelerates decomposition over time. The hypothesis is that the e-field
retards growth of certain bacteria inside the meat.
Set your function generator for a 1 volt output, separate two probes
by 1 centimeter, place 0.99 centimeters of steak between. I will hope
your grade isn't scored in competition to others puting their effort
into more voltage across smaller gaps.

73's
Richard Clark, KB7QHC