Shots Across the Bow

A Reality Based Blog

 
Friday, May 02, 2003

Human eggs from embryonic stem cells

According to this report, a research team has developed a way to generate egg cells from embryonic stem cells.

Ok, my biology is a little rusty, but all the cells in the embryo are diploid , which means they have a full genetic information, ie 46 chromosome aligned in 23 pairs. An egg cell is haploid, meaning it carries 23 chomosomes, one from each pair. It must be fertilized by sperm to get the remaining half. So how can you go from a diploid cell to a haploid cell?

Normally, reproductive cells must undergo a process called meiosis in order to produce haploid cells. It turns out that the stem cells harvested from embryos are the precursor to the germ plasm, which is the reservoir of stem cells which form the spermatagonia and oogonia, the precursors of sperm and eggs. These stem cells naturally undergo meiosis, so the new discovery is a matter of stimulating meiosis, and isolating the oocyte.

So what does this mean to me and you? Well, it could be possible for a man to produce viable eggs for one thing. It also means that eggs could be produced from an infertile woman, whcih cloud then be fertilized in vitro, and she could have a baby that isn't a clone. Or two same sex parents could have offspring which is a genetic blend of both of them, just like a traditional baby. Think about it; Chuck and Bill can have a baby and both of them would be biological parents. Or Sally, who can't have a baby because her eggs were damaged by a childhood disease can have undamaged eggs generated and have a baby. Or Bob, who's sperm was wiped out by measles, can have new sperm generated, and be a father.

But there are some caveats. All of these possibilities require the initial generation of an embryo from cloned tissue; the embryo must be destroyed in order to harvest the stem cells to generate the sperm or egg, and, as was recently reported, cloning of primates is proving to be significantly different than cloning other mammals.

Posted by Rich
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Wednesday, April 30, 2003

More on SARS

I was listening to NPR on my way into work and they had an update on the SARS epidemic in China. According to the report, Biejing is averaging 100+ new reported cases per day, and that is not counting the cases in rural areas where tracking is scarce. She reported that the mass exodus from Beijing has exported the disease to those rural areas, and new infections are appearing there.

She also brought up an interesting point that the seriousness of the epidemic is in no small part due to the attempts of the Chinese gov't to cover it up.

Also, Fox is reporting that some patients in Hong Kong have suffered relapses after being pronounced recovered.

Here are the latest figures from WHO on the SARS outbreak While the disease appears to have peaked in most areas, it's still roaring through China. I expect that when the full extent of the rural cases is known, the total number of cases will explode upwards. Given that care in rural areas will be significantly less than that in Beijing, we can also expect the death toll to rise.

Posted by Rich
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Friday, April 25, 2003

More on SARS

Yesterday, I posted a piece making fun of Michael Fumento, who downplayed the significance of SARS. Also yesterday, as part of the Volunteer Tailgate Party, I linked a piece by manish of Damn Foreigner, who argued that SARS is not a significant threat.

Diversity is a wonderful thing, but even more wonderful is the fact that we both are correct.

How?

Well, it's a matter of perspective. My problem with Fumento is he was arguing that the reaction to the SARS outbreak was driven by greed, not any genuine concern, and that SARS was a minor problem. Manish argued that the individual has relatively litle to fear from SARS, at least right now. The two arguments don't conflict, because they are from different perspectives.

Manish argues from the individual point of view. 140 cases out of a population of 4.7 million means that the average person has little to fear. The risk is negligible.

However, from an epidemiological stand point, a virus with a mortality rate of 15% is quite serious indeed. Particularly when the virus mutates as frequently as this one does. While the variants today appear to be diffcult to transmit, that could change quickly, leading to devastation equal to the pandemic of 1918. Therefore SARS is a quite legitimate concern for the WHO and CDC.

It's all in the perspective.

Posted by Rich
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Thursday, April 17, 2003

Once again, we see that we don’t need embryonic stem cells.

Adult stem cells have been used in more successfull therapies than embryonic. The latest from New Scientist:
Treatment with adult stem cells has cured mice suffering with a form of multiple sclerosis, say Italian researchers. Almost a third of the mice recovered completely from paralysis of their back legs, and the rest all showed substantial improvement.

"It was amazing," says Angelo Vescovi, of the San Raffaele Hospital in Milan. He has now begun experiments giving human adult stem cells to monkeys with the nerve and brain damage seen in MS. But he warns that success in mice does not guarantee success in humans: "I wouldn't want to raise expectations."


With success after success for adult stem cell therapies, and setback upon setback for embryonic stem cell therapies, why is there such a push to do such ethically troubling work? Could there be a political agenda?

Naah. I'll leave the dark conspiracies to Bubba. He's better at them than I am.

Posted by Rich
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Wednesday, April 02, 2003

I can see clearly now…

and that's a problem.
Conventional thinking is that space and time can be thought of together as a sort of foam. As light travels through the foam, it ought to be disrupted, ever so slightly, such that by the time it crosses much of the universe it would render only blurry pictures when gathered by a precision telescope. Put simple, Hubble ought to see a pixilation effect when photographing distant objects.

It does not. Hubble pictures are crisp and clear, no matter the distance to the object.


"So what," you say?

Well, if the quantum foam doesn't exist, then neither do we. You see, the current dominant theory for the origin of the universe involves special properties of this quantum foam, namely it's tendency to "blow up."

Here's how it breaks down:

Heisenberg's Uncertainty principle tells us that below a certain size, it is impossible to know both the momentum and position of a particle. Even further, it tells that those quantities are undetermined until we measure one of them. As contra-intuitive as it sounds, a sub atomic particle does not have a defined position or momentum until we measure it.

Physicists have used that indeterminacy to derive a theory for the origin of the universe. Basically, the universe was at zero. There was nothing. But zero is subject to uncertainty, so there were quantum level fluctuations around zero, called the quantum foam. Under certain circulstances, those fluctuations in the foam could blow up, creating massive amounts of mass/energy, or spacce/time, depending on your frame of reference. Such an explosion is theorized to be the origin of our universe.

The problem is that quantum foam should be detectable as perturbations in light, which would appear as distortions in images captured by the Hubble telescope. The absence of the distortion indicates the absence of the quantum foam, which has disastrous implications for our theory of the origin of the universe. While it is early yet, it appears that the quantum foam may well join aether as a failed scientific model.

As a side note, aether is making a comeback of sorts, with proponents ranging from crackpots to serious scientists.

Well, we may not know how we got here, but at least we know we are here. Unless you are a philosopher, in which case, you might not be too sure about that either.

Come to think of it, I know I'm here, but I'm not all that sure about you. Tell you what; confirm your reality by hitting the tip jar to the left.

Posted by Rich
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Thursday, February 27, 2003

New Hydrogen production methods

SK Bubba links to a couple of experiments dealing with new ways to generate H2. The hope is to find an inexpensive way to generate H2, making fuel cells practical.

The first link is to ORNL's experiment in producing H2 by photosynthesis. They say that they are producing close to the theoretical maximum of 12 moles H2 for every mole of sugar processed. Unfortunately, the article doesn't give us relevant info like time and area required, but we'll go with what we have.

A mole of sugar weighs approximately .4 lbs and a mole of H2 weighs approximately .004 lbs, so we have a 8:1 relationship. So 8 kilos of sugar will be converted to 1 kilo of H2.

The energy value of a kilo of H2 is about 33.3kWh, and a fuel cell will utilize about 60% of that, or 20kWh. 20 kWatts is equivalent to approximately 27 horsepower, so assuming a car runs with 150 horsepower, the energy from 100 kilos of sugar will run the average car for about 10 minutes. 8 kilos of sugar is about 18 pounds for those of us who hate the metric system.

That's a lot of sugar.

In his second reference, the process uses specially designed membranes to catalyze the splitting of water into H2 and O2. reading the patent claim, I discovered that the process takes place at around 1000 degrees centigrade, or 1832 degrees F. That's going to take some significant energy to maintain. While it may make it less inefficient to liberate the hydrogen, it still doesn't get us past the laws of thermodynamics.

No matter how many clever ways we try to get around it, you can't get out more than you put in. But what fuel cells and hydrogen technology might do for us is lower the back end costs, pollution, environmental damage, etc to the point where the additional front end costs are compensated for. Looked at from that perspective, every little bit helps.

Posted by Rich
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Wednesday, February 26, 2003

Computers in DNA

No sooner than I finish making fun of Michael Drosnin do I find this article in National Geographic:
Israeli scientists have devised a computer that can perform 330 trillion operations per second, more than 100,000 times the speed of the fastest PC. The secret: It runs on DNA.


Now, how's a guy supposed to make fun of wild speculations when these darn scientists keep going out and turning up proof in support of them?

It's just not fair....

Posted by Rich
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Tuesday, February 25, 2003

Hybrid cars…that’s the ticket!

This week's issue of the Metro Pulse has a story on hybrid cars, the ones that run on both electric and internal combustion motors. They made an attempt at explaining the technology, but they are limited to a few hundred words, where I, you lucky readers, can go on at length.

And I will.

Regular readers know that I am against the concept of hydrogen powered, or fuel cell cars, because they don't save energy at all. In fact, as I demonstrated, they actually use more energy due to transformation losses.

So, you're probably thinking that I won't like hybrid cars either.

Wrong. Hybrid cars reduce many of the inefficiencies of the IC engine, without the ancillary costs of a fuel cell. Let's look a little deeper, and you'll see what I'm talking about.

We have to start with mileage, because that's the measure of efficiency of a car. There are several factors that affect your mileage, some designed, which you can't control, and others operational, which you can. Examples of the first include gear ratios, tire sizes, and body aerodynamics, while examples of the latter include velocity, magnitude of acceleration, magnitude of deceleration, and routine maintenance. Let's look at the engineered factors first.

Body aerodynamics and gear ratios are the two biggest factors affecting your mileage. The aerodynamics determines how hard it is to push your car through the air, and the gear ratio determines how hard the motor has to work to push the car. Aerodynamically, the smoother the air flow is around your car, the less resistance, or drag is produced, and the easier it is for your car to slide through the air. Automakers spend millions on wind tunnel tests, determining which body designs provide the smoothest air flow.

Gear ratios determine how efficiently the power of the engine is converted into thrust. The selection of a gear ratio is always a compromise between torque, speed, and economy. A very economical gear ratio will have a limited top end, and minimal torque. Conversely, high torque or high speed reduces efficiency. Car makers try to achieve the optimum balnce by providing multiple gears, which can provide low end torque and high end speed, while still giving decent fuel economy.

If you've ever driven a stick shift, you know what I mean. I drive a 4 cylinder 1.6 liter Tracker with a 5 speed stick. Depending on how I choose my shift points, my mileage can vary by .75mpg. An automatic transmission has programmed shift points; the auto maker selects those points based on his target buyer. A Corvette with automatic (sacrilege, but I'm just making a point) will shift differently than a Yugo. (Boy, will it shift differently!)

Now, each gear has a performance curve associated with it, also called a power band. Basically, this curve represents how efficiently the power from the engine is converted to thrust. For each gear ratio, there is a point where maximum power is transferred to the wheels. Once you hit this peak, any additional energy input, ie standing on the throttle, produces diminishing returns. Returning to my Tracker, if I increase my average speed on the Interstate from 70 to 75mph, my mileage decreases by about .5 mpg. (Yes, I track these numbers. I am a nerd.)

Now we've seen how different factors affect our fuel economy. So what do hybrids do to help us?

Well there are a couple of things. IC engines are most efficient when you are running in the power band, and running steady state. This is why highway mileage is significantly higher than city. It isn't sitting at lights the burns the gas; it's the starting and stopping. Think about it; as you accelerate, you spend most of that time outside of the power band, at lower than optimal efficiency. If you accelerate quickly, you're even further from the optimum, resulting in even worse efficiency.

But what about braking? You're not giving the engine any gas; how is that inefficient?

One of the factors which makes operating at steady state so efficient is that the car is acting sort of like a battery, storing energy in the form of momentum. This goes back to the first of Newton's Laws of Motion, that an object in motion tends to remain in motion. Most of the energy produced by the engine during acceleration is stored in the car's momentum. Once you've reached cruising speed, the engine only has to produce enough energy to overcome friction and drag. The problem with braking is you take all that lovely stored energy, and waste it as heat. You get no benefit out of it.

Here's where the hybrid comes in. Instead of friction braking, a hybrid uses electromagnetic braking.

I can see your eyes glazing over.

It's not that complicated. Here's how it works. A while back, some smart people found out that if you passed electricity through a wire, you generated a magnetic field. Then they found out that if you wrapped the wire in a certain way, the magnetic field would rotate. Stick a chunk of iron or a magnet in the middle of this rotating field, and you've just converted electrical energy into mechanical energy, and made the worlds first motor. Pretty cool, but it gets better.

Another smart guy wondered what would happen if you went backward, and moved a wire through a magnetic field. He was shocked to find out that it generated electricity. (Sorry, it's late and I couldn't resist...)

Now here is where is gets a little confusing. Run a wire through a magnetic field, and you generate a current through the wire. But now that you have a current running through a wire, you're generating another magnetic field, only this one is opposed to the first. This magnetic field is called a Counter electro motive force, or cemf for short.

And now we're back to the electromagnetic braking. When you hit the brakes on a hybrid, you get some conventional friction braking, but you also cut in a coil surrounding a magnet on the axle. The magnet creates a field which moves around the coil, generating electricity. This electricity is stored in the hybrids battery, for whenever it is needed next. This is just too cool, because a lot of that lovely energy that used to be wasted is saved to be used again later, greatly increasing the efficiency of the car.

Now we're getting towards the end, and if you've stayed with me this far, you're almost home. (there will be a test at the bash, so please pay close attention)

OK, so we're saving energy by electromagnetic breaking. Where does this energy get used?

Well, that depends on the hybrid your talking about. All systems use the energy to supplement the IC engine when it isn't running at optimal efficiency. Some do so during acceleration, others do it at low speeds, others a combination of both. In any case, you have a double benefit; you have an assist when IC is inefficient, and you capture a large portion of energy formerly wasted in breaking.

It truly is a win-win situation.

One last point before I go to sleep. An efficient IC engine is a clean running engine. By augmenting or replacing the IC engine when it can't run at peak efficiency, the hybrid reduces emissions even more than the improvements in economy would suggest.

So, it runs better, cleaner, and cheaper. It's a little more up front, but you'll recover that and more in fuel savings over the life of the car.

My next car will be a hybrid.

Good night.

Posted by Rich
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Wednesday, February 05, 2003

Fumento on Atkins

I just finished reading Michael Fumento's latest piece against the Atkins diet in the newest issue of reason. According to him, the Atkins diet does not work, is probably dangerous, and is partially responsible for the obesity epidemic in America. This new article repeats inaccuracies and misstatements I critiqued in an earlier post.

First a personal disclosure: I followed the Atkins diet from March through Oct of 2002. During that time, I lost 80 pounds, most coming in the first 4 months. My total cholesterol has dropped 30 points, my HDL has gone up 10 points, my triglycerides have dropped significantly. My total cholesterol/HDL ratio is under 5 for the first time in years. My blood pressure has dropped from 135/95 to 115/72. In short, by every medical measure, I am significantly healthier than before I went on the Atkins diet. My results are more impressive than most because I also started a modest exercise plan.

More importantly, I was able to stay with the diet easily, while the traditional low fat diet simply did not satisfy me. I was able to eat the foods that I liked, avoid the carbs, and lose the weight. It was much easier for me to find carb substitutes than fat substitutes. Crushed pork rinds mixed with soy flour make an excellent breading for fried chicken or pork chops. Throw in some Hooter's Wing Sauce, and a big burger without the bun, and you can watch the Super Bowl with your buddies and not feel deprived. I could go out to resaurants and instead of eating bland, unsatisfying but "heart healthy" choices, I could eat a big Ceasar salad with dressing, skipping the croutons, enjoy a nice steak with a portabella mushroom sauteed in red wine, and asparagus with cream sauce, without busting my diet. Of course, I couldn't eat like that every day, nor does the plan suggest that you can.

Not only did I look better; I felt better. While on the diet, I never felt bloated, never had heartburn, (even before I lost the weight), and had much more energy. I noticed this more when I went off the diet than when I was on it. When I started eating a lot of carbs again, my body slowed down. I started sleeping more, and I didn’t have the energy I had gotten used to having.

It’s now February, and I’m going back on the plan. I went off over the holidays, and gained some of the weight back. My goal now is to get back to 225, then lose an additional 20 pounds. I’ve been in induction for 5 days, and I already feel better. I’m alert, clear-headed, sleeping better, and feeling better. One other benefit I haven’t seen mentioned anywhere else is that my teeth stay cleaner, with little to no plaque buildup.

As for Fumento’s new article, he repeats the same tired accusations yet again, even though if he’s read the book, he knows they are false. For example: (quotes are from the article, “Big Fat Fake” from issue 3.03 of reason magazine.)

  • ”Dr. Atkins claims that by simply minimizing your carbohydrate intake, you can quickly lose massive amounts of weight, even while pigging out on fatback, pork rinds, and lard.”
    I challenge Mr. Fumento to point out one single reference in any of the doctor’s books where he advocates such a plan. It simply does not exist. Dr Atkins goes so far as to state that if you do ‘pig out’, as Mr. Fumento puts it, you will not lose weight. Repeatedly, Dr. Atkins recommends that you limit your carbs, then eat protein and fat until you are sated.

  • “Hill’s co-researcher, Gary Foster of the University of Pennsylvania, says ‘the probable explanation for the greater weight loss in the groups on the Atkins regimen’ is that it ‘gives people a framework to eat fewer calories, since most of the choices in this culture are carbohydrate driven….You’re left eating a lot of fat, and you ge tired of that. Over time people eat fewer calories.’ That would make the Atkins plan nothing more than a low calorie diet in disguise.”
    First, they admit that Atkins dieters lost more weight than AHA and other diets tested. This is a bad thing? Next they “blame” the loss on a reduced calorie intake. Again, this is bad? Hey, any diet which allows me to consume fewer calories while enjoying them more, bring it on!

  • Fumento quotes from a 1973 study of the Atkins plan published in JAMA. “The notion that sedentary persons, without malabsorption or hyperthyroidism, can lose weight on a diet containing 5,000 calories a day is incredible.”
    Yes it is. But I can’t find anywhere in The New Diet Revolution which states that premise. Another challenge to Fumento; show me where Atkins recommends consuming 5,000 calories per day.



There are legitimate criticisms of the plan, and it might not work for everyone. However, most of the poeple I know who have tried the plan have lost weight. But any diet is only as good as you are at staying on it, and we will all lapse, whether we are on a low carb or a low fat diet. The key to long term weight loss isn't diet, it's exercise, a fact that Fumento does mention but only in passing. Instead of promoting what actually works, exercise, he instead spends his time attacking a diet which by anecdotal and now scientific evidence is a safe, effective way to lose weight. What is worse is that he carries out this attack using misinformation.

Posted by Rich
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Tuesday, February 04, 2003

Project Prometheus lives! (sort of)

Well, it didn't make the SOTU speech, but nuclear powered space flight is on the way.
To develop and demonstrate new power and propulsion technologies to overcome these limitations, the President's Budget proposes $279 million; ($3 billion over five years) for Project Prometheus, which builds on the Nuclear Systems Initiative started last year. Project Prometheus includes the development of the first nuclear-electric space mission, called the Jupiter Icy Moons Orbiter.


Looking at the breakdown of the budget provided, it looks like most of the money goes to JIMO, a robotic mission to Jupiter's moons which will use the first nuclear electric propulsion unit. It looks like actual spending on nuclear fissionpropulsion is actually cut by 22 million, and nuclear power by 5 million, deferring those costs to FY2005.

Of course, this budget still has to make it through Congress, and they usually slash away at NASA, although that may be more limited this year by Columbia.

Posted by Rich
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Sunday, January 05, 2003

Nuclear Power--at last!

Mr bubba asked me to do a bit on nuclear power, pros and cons. I've been putting off the job, mainly because it's been the holidays, and I'm lazy. But the holidays are over, and while 'm still lazy, since I've been writing some science stuff lately, I figured now was as good a time as any. besides, some of the stuff I talked about on global warming comes in to play here as well (which is where I learned it in the first place).

So saddle up boys and girls for a quick primer on nuclear physics.

First I have to tell you that I'm simplifying this stuff tremendously. If any real nuclear physicists read this, please take that into accountbefore you laugh and call me names.

My parents used to ask me what I did in the Navy. Since I didn't want to tell them what I did while on liberty in foreign ports, I told them about my job as a reactor operator.

"I boil water," I'd tell them.

That's really all a nuclear reactor is; it's a big tea pot. See, the best way way we've found to generate electricity is through electromagnetism. If you move a wire through a magnetic field, you induce a current in the wire. It's like magic, only without the wand. The rub is that you have to keep moving the wire through the magnetic field to keep generating electricity. So what we did was make the wire into a coil, and stick a magnet in the middle. Then we attached a rod to the wire, and spun the rod. This is called a generator. The guy spinning the coil would get tired after a while, so next we had to find a way to keep the rod turning. Now this was an easy problem to solve, because we had these steam engines lying around that were great at keeping things turning, so we attached a steam turbine to the coil, and made a turbine generator, which takes heat energy from the steam and converts it to electricity.

Now our next problem is how to boil the water, and this is where the nuclear part comes in. We've used fuels like wood, coal, oil, and alcohols, all of which work to varying degrees, but we wanted something better, something that didn't take quite so much effort, didn't cause acid rain and smog, something that wouldn't run out in a few centuries.

About that time, Ms Curie and several thousand of her closest friends discovered how to get at the energy inside an atom.

Now, if you remember your science from high school, you'll remember that the atom has electrons (negative charge), protons (positive charge), and neutrons (no charge). The electrons hang out in a cloud around the nucleus, which is made up of protons and neutrons. This nucleus is what we are interested in. We've all messed around with magnets when we were kids and we know that like charges repel each other. So how then does the nucleus hang together, since it is filled with protons, which all have like charges?

Well the answer is that there is another force at work in the nucleus, one that is stronger than the repellant force of the like charges, and as long as the protons and neutrons are kept close enough, this force holds the nucleus together. We'll call this the binding energy of the nucleus. What scentists discovered was that if you hit a nucleus hard enough, and at the right spot, you overcome this binding energy, and the nucleus splits, or fissions. When this happens, the binding energy is released as heat.

Now, working at the atomic level, the heat released is too small to be noticed. What we have to do is make this happen in millions of atoms, and go on happening. Until we want it to stop. A guy named Oppenheimer found a way to get the energy to come out, but it comes out all at once, and doesn't stop until all the fuel is used. Not very good for our purposes.

Well, what we found was that one of the best ways to split a nucleus was to hit it with a neutron. We also found that when a nucleus splits, it doesn't split evenly, but in different sized chunks, and a few stray neutrons. All we had to do was find a way to get those stray neutrons to cause more fissions, releasing more neutrons, and so on, creating a chain reaction. Sounds simple, yes?

No. It took years, and many experiments before we found the proper configuration where the number of neutrons released in each generation would be enough to keep the reaction going, without growing out of control, or dying out. What we did was to pile large amounts of uranium in very tightly defined arrays, with graphite rods between them. We use uranium because it is naturally radioactive, and fissions all by itself. The rods absorb the neutrons, keeping a chain reaction from occurring. When we want to start the reactor, we pull the rods out, allowing the neutrons to build a chain reaction and grow in strength to generate the heat we need to boil the water. If we need more power, we pull the rods out further; less, we push the rods in.

Obviously we are generating a lot of heat when we operate the reactor, and we have to cool it to keep everything from melting. (Not to China. Like nearly everything else out of Jane Fonda's mouth, the China Syndrome is BS. A reactor when it melts loses the configuration to maintain the chain reaction. Fission halts and the metal cools. It leaves a hell of a mess behind, but it isn't going to bore a hole all the way to the core. We proved that with Three Mile Island) To keep the reactor cool, we run water through it. It takes the heat out of the reactor, (through conduction and convection), and carries it off. Now this is the cool part, because this water is so hot, it flashes to steam, which we use to run our turbine generator to make the electricity.

It's like we planned this or something....

It sounds so simple; what's all the fuss about?

If that was all that was going on, it would be simple. Unfortunately, there are some other types of radiation given off, and other efects that we have to deal with.

Which we will discuss tomorrow.....

Posted by Rich
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Friday, January 03, 2003

Global Warming--the real story

Ok, folks, time for another science lecture from yours truly. Sorry, SK, it isn't on nuke power this time, but that's your fault for getting this whole global warming thing going! By the way, for those of you who haven't checked it out, there's a nice lttle exchange going on in the comments to SKBubba's post here. True to my style, I have to break out of there, and go long form.

Hope you all took naps, because this could take awhile.

In all seriousness, this is an important issue, and you have to understand the basics before you can evaluate the laims of the various sides. I don't want you to just take my word for it; that would be just as bad as the greenies who believe just because Ralphie tells them to. Check out the links I provide. Check their references. Go get a basic science text out of the library, or at the used book store.

Ok, first we have to talk about the proposed mechanism of global warming. Simply put, the global warming theory says that man is in effect putting a blanket over the entire planet by emitting greenhouse gases, primarily CO2. The theory says that the CO2 rises into the upper atmosphere where it acts as a one way heat sheld, trapping radient energy from the sun, and causing the earth to heat up.

Why does that make the earth heat up?

Glad you asked. Now we venture into the world of thermodynamics. It's a little scary in here, but don't worry, I'll hold your hand.

Heat is transferred across a difference in temperature. If you hold something hot next to something cold, the temperature will equalize between them, as heat energy is transferred from the hotter item to the colder item. The rate of the transfer is driven by the difference in temperature between them; the larger the difference, the faster the transfer. Here's the key; without a difference in temperature, no transfer takes place, and energy transfers always go from hotter to colder. Remember this. It's key to why global warming cannot occur as the current model states.

OK, now, there are three ways that this heat energy can be transferred;
  1. Conduction--the two items are in direct contact
  2. Convection--the two items are separated, but a transfer medium envelops them both. This can be air, water, whatever.
  3. Radiation--the two items are separated, but energy is transferred without a medium. This is how the sun warms the earth through a vacuum.
So the sun warms the earth directly, through radient energy. That energy is trapped on the earth by our atmosphere through the greenhouse effect. But how does it work, exactly?

OK, first, the sun is the radient body. It send energy to the earth which absorbs it, growing warmer. Once the earth is warmer than the atmopsphere, it becomes a radient body, transferring energy to the atmosphere via conduction and convection. As the atmosphere warms, the temperature difference between it and the earth decreases, slowing the transfer rate. This allows the earth to hold more of the sun's energy, staying warmer. Eventually an equilibrium is reached, where the rate energy is radiated to the earth by the sun is equalled by the rate energy is radiated by the earth into space. Luckily for us, this equilibrium occurs at a temperature we find comfortable.

Now, global warming theory suggests that man-made greenhouse gasses are accumulating in our atmosphere, shifting the equilibrium point higher. The gasses build up in our upper atmosphere, in effect pulling a blanket over the planet.

Now, in order for our blanket to have a warming effect, it must slow the heat transfer from the lower atmosphere, aka the troposphere, to the upper atmosphere, beyond the greenhouse layer. Like we stated above, the rate of heat transfer is affected by the difference in temperature. Therefore, we should see an increase in temperature in the greenhouse layer if it is causing the equilibrium shift.

As has been noted in many places, tropospheric temperatures are not increasing; in fact they are decreasing. As we have learned, thermodynamically this would mean that heat transfer would increase, cooling the earth, rather than heating it.

The second link above attempts to explain away this discrepancy by positing the presense of contaminants in the stratospheric layer, which artificially reduce the temperature of the troposphere.
While a combination of human activities and natural causes has contributed to rising surface temperatures, other human and natural forces may actually have cooled the upper atmosphere. For example, natural events such as the eruption of Mt. Pinatubo in 1991 tended to decrease atmospheric temperature for several years. And burning coal and oil for energy produces tiny aerosol particles in the atmosphere that can have a cooling effect. Upper-air temperatures also can be reduced by depletion of ozone in the stratosphere caused by chlorofluorocarbons and other chemicals being emitted into the atmosphere. When these variables are accounted for in atmospheric models, satellite and balloon data more closely align with surface-temperature observations.


Thermodynamically, this makes no sense. The cooling effect noted results primarily from blocking solar radiation above the troposphere, resulting in a cooler troposphere and a cooler earth. the drop in both allows the equilibrium to shift and stabilize at a lower level. This is readily demonstrated by observations following Mt. Pinatubo's eruption in 1991, which are welldocumented. The presence of aerosols in the stratosphere results in cooling in both the troposphere and the surface.

But we are seeing rising surface temperatures and cooling tropospheric temperatures. How can this be?

Let's look at the thermodynamics again. We said that heat transfer is driven by temperature differential. We are begining to see a larger differential, so it stands to reason that the energy transfer rate has increased as well. remember that the earth is in equilibrium with energy input from the sun equalling energy radiated into space. If we are radiating more energy, then we must also be recieving more energy; otherwise the earth would be cooling. Let's take a look at the amount of energy the sun is sending us. Lo and behold, we find that we are in a peak of solar energy output. In fact, if we graph what we know of global surface temperature against solar activity, we find a very close correlation. The following chart, reproduced from this site, and originating from
Baliunas, S. and Soon, W. (1995) Astrophysical Journal 450, 896-901; Christensen, E. and Lassen, K. (1991) Science 254, 698-700; [sbaliunas, ].

demonstrates this correlation.


fig3.gif

Thermodynamically, it all makes sense. More energy is transferred from the sun to the earth, resulting in a higher surface temperature, which causes a higher differential temperature from the earth to the stratosphere, resulting in more heat being radiated out, maintaining equilibrium.

Anybody still awake?

Good, cause now it gets really fun. The enviros will cry out at this point about the "tons of emmissions we are producing every year, through our wasteful ways, our SUV's, and such. Surely that has some effect?"

Well, let's take a look. The accepted figure for human related CO2 emissions is 5.5 gigatons of carbon per year. That's 11 trillion pounds of carbon! That's monstrous, isn't it?

Well, not really. The atmosphere already contains about 750 gigatons of carbon. In addition, the earth exchanges about 150 gigatons of carbon with the atmosphere yearly. So we have an equilibrium of 750 gigatons, with a dynamic exchange of 150 gigatons, and we are worried about 5.5 gigatons?

Ok, if CO2 emissions were the only factor in the greenhouse equation, then we might need to worry in 300-400 years. The cumulative effects could begin to cause problems in that time span, but that hardly means we need to panic now.

However, CO2 is not the only factor. In fact, it is a minimal factor in the overall greenhouse effect. Water vapor, both as humidity and cloud cover, represents a tremendous heat shield and far outweigh the effects of CO2. Even a massive increase in atmospheric CO2 would only have a small effect on the greenhouse effect.

So, why the big fuss? If there's nothing to worry about, why are all the scientists concerned?

Well, first, not all the scientists are concerned, and some who were are no longer as concerned. Remember, scientists are very conservative. Once a position is adopted, regardless of whether it is sound or not, it takes a long time to get them to change their mind. Look at how strongly Einstein resisted quantum theory. Add to this natural conservatism the current political and ideological climate, and it is much easier to go along with the flow, rather than to stand against it.

Ok, this post is almost done, but now it's my turn to equivocate. The earth's surface temperature is rising. It is possible that man's activities has something to do with it. It is also possible that this is a bad thing. But it hasn't been proven yet. It hasn't even come close to proof. Even so, some are using this possibility to extort billions from the US, and that is all Kyoto was designed to do. If we do find evidence that man is changing the earth's climate, AND we have evidence that this change will be abd, then we should act. As of now, both possibilities are remote. They are worth exploring, but no more.

Posted by Rich
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Monday, November 18, 2002

Modern Science at work

A team of British researchers has discovered that television is so popular because it combines sound and vision.
Human brains are genetically programmed to enjoy television, research has suggested.
A Manchester University study found watching television exercised both sides of the brain, making information easier to understand.

Researchers said that the brain also assimilates information best through sound and vision, which is why TV works so well.


Three months and how many pounds to determine that the brain evolved to handle audio and visual information?

Yeesh!

Posted by Rich
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Saturday, November 16, 2002

More on fuel cells

William Burton asked an interesting question in the comments on my first fuel cell posting. While I addressed it there, it did make me curious. Could the ancillary benefits of fuel cells outweight the costs? I decided to do a little research, followed by some low rent modeling to see exactly where things fell out.

Let's start with the IC engine. As technology has improved, we have come a long way in IC engine efficiency. Today, a standard engine runs in the neighborhood of 32% efficient, not counting drive train and friction losses, which will be the same regardless of power plant design.

Obviously, this is far worse than the 85% efficiency achieved by the fuel cell. The problem comes when we fuel the cell. Making the hydrogen requires cracking water, and the standard method involves electricity. A steam generating plant, whether fired by coal, fuel oil, biomass or some other fuel typically runs at about 34-38% efficient. So combining the steam plant with the fuel cell efficiencies gives us a range of 28-32%. So, in the best case, we merely equal the efficiency we already achieve, at a greatly increased cost. We're using the same amount of fuel, or better, resulting in the same environmental impact, the same dependence on foreign oil, only we're spending a lot more money to do it.

Now, let's examine solar power for a moment. I did a quick search on the net, and the best efficiencies I could find for solar voltaic conversion was 28.7%, and that was using a terrestrial version of solar modules designed for use on satellites. The cell yielded 2.571V at 12.95mA/cm2 on a 30cm2 area. A standard solar cell usually runs at around 12% efficient, giving 10mW at .6V on a 2 cm2 cell.

Time to pull out our trusty conversion calculator. We'll assume we have economical access to the super cell.

Power=Voltage X Current=2.6V X 12.95mA/cm2 = 33.7 mW per cm2, or 1010mW per cell.

Let's assume a typical power plant size of 700MW.

700MW/1010mW per cell=693 million cells or 746,000 square feet, or just over 17 acres of solar panels. Except it will probably be more like 21 acres, if you figure 20% overhead for operating equipment, framing materials, access paths for maintenance, etc.

My trusty Pocket Ref tells me that 1 horsepower is equal to 746 W so this 700MW power plant will produce 940,000 horsepower. Now to make things easier, we will neglect conversion losses and assume that all available power is transformed from electricity to hydrogen. The true efficiency is probably around 95%, so we aren't introducing much error. However, we do have to account for the 85% efficiency of our fuel cell, which reduces our available horsepower to 800,000. Next, we'll assume that the auto fuel cell is around 100 horsepower. We'll also assume utilization at 10% since cars do sit idle most of the time, giving us an effective horsepower of 10. Now we have a grand total of 80,000 fuel cells per 700MW power plant.

Now, at any given time, there are approximately 175 million cars in the hands of our get up and go population, meaning we will need almost 2200 new solar power plants just for the auto industry alone. 2200 plants at 22 acres per plant, add in another 15 acres (very conservative) for physical plant, parking etc, and you have 48400acres, or 76 square miles of solar panels.

Next we have to consider the costs of constructing a delivery system for the hydrogen, one which is efficient, and safe. Liquids can be piped relatively easily. Designing a nation wide network of pipes to contain hydrogen proves to be trickier, and significantly more expensive.

So, at a rough glance, in order to replace the IC engine with fuel cells, we will need to construct 2200 new power plants, whether solar or conventional, and develop a nationwide delivery system for a very volatile gas. As SKB suggested, there are stabler forms of hydrogen, but none of those forms are suitable for fuel cell use, except methanol, which involves CO2 emissions, negating the chief advantage to the fuel cell. As far as I can tell, the benefits are minimal, compared to the expense.

Posted by Rich
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Thursday, November 14, 2002

Fuel cells and other myths

There's a little discussion on fuel cells going over at SKBubba's house, and I wanted to add my two cents worth. I put an abbreviated version of this in the comments section over there.

There is a tendency for people to see fuel cells as the solution to all our energy problems.

"It burns hydrogen, not oil, and produces clean water as it's only emission. How wonderful! We are saved from pollution and the Middle East at the same time!"

Unfortunately, while the above is true, it only represents half the story. There is a little known flaw in this panacea that dooms it to marginal success, if not abject failure. Come with me while we explore...

The Dark Side of the Fuel Cell (Cue the spooky music.)

Our story begins with the laws of thermodynamics. Unlike election campaign laws, these laws are inflexible and cannot be ignored, no mater how much politicians might hope. Breaking them is out of the question, as is bending them, except at the quantum level, but we don't want to go there.

Trust me, we don't.

The first law says that energy and matter can neither be created, nor destroyed, only altered. In essense, you can't get something for nothing, despite what the late night infomercials tell you. The second law says that in any closed system, energy tends to decrease, while disorder tends to increase. In short, you'll never get outt what you put in. Except when you dig a hole For some reason, you always have more dirt than when you started...but I digress. These two laws are iron clad. Unbreakable. Mother nature enforces them with utmost strictness, and you know what a mother she can be.

So, let's see how those laws apply to our happy little fuel cell.

First, hydrogen doesn't play nice. Where oil plays hide and seek, once you find it, it comes along quietly to the refinery. Hydrogen, on the other hand, has to be dragged kicking and screaming away from oxygen, cause they really get along very well. It takes a lot of energy to rip the two of them apart. Just picture two teenagers in the back row of the movie theater necking. While chewing gum. And wearing braces.

Got it?

OK, so now we have separated the hydrogen, and filled up our happy little fuel cell. All is right with the world now, right? So we drive down the road, and our car, instead of burning petroleum as fuel, burns hydrogen.

This brings us to the second part of our tragic tale. Burning is another word for oxygenation, or the addition of oxygen. What we are doing is allowing our teenagers to get back together again. In the process, the hydrogen and oxygen give off energy. How much energy you ask? (OK you didn't ask, but this post would end abruptly if I didn't ask for you.)

Here's where mother nature's cops step in and ruin the party. Law one says that the most energy we can extract from oxygenating (burning) hydrogen is the same amount we used separating them in the first place. Breaking even is the best we can hope for. Law two tells us that we can't even break even, that we will lose energy with each transformation.

Yes, there's a hand in the back?

"If law one says we can't destroy energy, where does this lost energy go?"

Good question, I'm glad you asked. The lost energy is radiated away in the form of heat and light, which are useless to us in this application.

The picture gets even worse when you figure in the efficiencies of the fuel cell, which runs around 83% for the ideal fuel cell.

Finally, hydrogen has a nasty tendancy to oxidize at a highly accelerated rate. In the lab, we call this an explosion. Think Hindenberg. Now picture every car on the interstate at rush hour being the equivalent of a Ford Pinto. Every fender bender would be a potential conflagration.

In essence, we haven't reduced our energy demands at all. In fact we have increased them, so how has that reduced our dependence on foreing oil?

The sad answer is that is hasn't. Fuel cells alone do not provide an answer to our energy problems. So why are we working on them?

Well, fuel cells do have some significant advantages over internal combustion.
  • They produce a clean exhaust, heat and pure water.
  • The conversion from chemical to electrical energy (fuel cell) is significantly (about two times) more efficient than from chemical to thermal (internal combustion), which translates into better mileage. Unfortunately, the increased production costs associated with manufacturing both the cell and the fuel more than offset this advantage.
  • A fuel cell coupled with small solar panels makes a good, clean back up power supply in stationary applications, ie office buildings.


So, while fuel cells are nice, they don't really buy us much in terms of reducing or dependency on oil. The bottom line is we need a new fuel source, one which is clean, cheap, dependable, and plentiful. The folks arguing for alternative fuels have yet to provide one which meets all of those needs. Solar conversion would be nice, but the efifciencies of solar cells makes the cost per kW prohibitive. Nuclear would work, but I don't see us exploring that path with any real enthusiasm. Hydroelectric would be nice, but unless we put turbines on every creek and waterfall, there just isn't enough to go around.

Assuming that we do crack the provlem of a cheap energy source, there is still the problem of distribution of the hydrogen. Either we lay hundreds of thousands of miles of pipes, or we transport the hydrogen via tankers, with the attendant risk of explosions. Since hydrogen production needs an abundant source of water, we can't spread out our power plants like we do now. Nor can each house have it's own fuel generation station, like some dreamers have proposed. I see another hand in the back...

"Why can't every house have a solar converter, hooked to a fuel cell for it's main power supply?"

You haven't been paying attention. This is the same ring around the rosie we dismissed earlier. OK, hook solar panels on your roof to a fuel cell in your basement. Use the solar energy to produce the electricity needed to crack the water into hydrogen and oxygen. Then oxidize the hydrogen in your fuel cell, and where are you? Even further behind than when you started. You converted sunlight into electricity(minus efficiency and thermo losses) then spent that electricity(minus efficiency and thermo losses) to crack the water, then got back the same energy during oxidation, minus efficiency and thermodynamic losses. You'd be better off skipping the fuel cell, and using simple solar conversion. Fewer losses that way.

Now as mentioned above, a solar/fuel cell combo makes an excellent back up power supply for a building. It's much cleaner, more efficient and significantly cheaper than batteries. However, it still comes up short as a primary power source.

So, what have we learned today?

Fuel cells run on hydrogen which does not exist in large reserves like oil, but must be manufactured.
Hydrogen is tricky to work with and tends to explode at the worst possible time.
Fuel cells, like every heat engine, consume more power than they put out.
Fuel cells alone will not reduce our dependence on foreign oil. In fact, it will increase it in the short run.
We still have to develop some alternative to oil power in order to make fuel cells a viable alternative to the IC engine.

And I have entirely too much time on my hands.....

Posted by Rich
Science • (5) CommentsPermalink


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