The main products of my company, REB Research, involve metallic membranes, often palladium-based, that provide 100% selective hydrogen filtering or long term hydrogen storage. One way to understand why these metallic membrane provide 100% selectivity has to do with the fact that metallic atoms are much bigger than hydrogen ions, with absolutely regular, small spaces between them that fit hydrogen and nothing else.
Palladium atoms are essentially spheres. In the metallic form, the atoms pack in an FCC structure (face-centered cubic) with a radius of, 1.375 Å. There is a cloud of free electrons that provide conductivity and heat transfer, but as far as the structure of the metal, there is only a tiny space of 0.426 Å between the atoms, see below. This hole is too small of any molecule, or any inert gas. In the gas phase hydrogen molecules are about 1.06 Å in diameter, and other molecules are bigger. Hydrogen atoms shrink when inside a metal, though, to 0.3 to 0.4 Å, just small enough to fit through the holes.
The reason that hydrogen shrinks has to do with its electron leaving to join palladium’s condition cloud. Hydrogen is usually put on the upper left of the periodic table because, in most cases, it behaves as a metal. Like a metal, it reacts with oxygen, and chlorine, forming stoichiometric compounds like H2O and HCl. It also behaves like a metal in that it alloys, non-stoichiometrically, with other metals. Not with all metals, but with many, Pd and the transition metals in particular. Metal atoms are a lot bigger than hydrogen so there is little metallic expansion on alloying. The hydrogen fits in the tiny spaces between atoms. I’ve previously written about hydrogen transport through transition metals (we provide membranes for this too).
No other atom or molecule fits in the tiny space between palladium atoms. Other atoms and molecules are bigger, 1.5Å or more in size. This is far too big to fit in a hole 0.426Å in diameter. The result is that palladium is basically 100% selective to hydrogen. Other metals are too, but palladium is particularly good in that it does not readily oxidize. We sometime sell transition metal membranes and sorbers, but typically coat the underlying metal with palladium.
We don’t typically sell products of pure palladium, by the way. Instead most of our products use, Pd-25%Ag or Pd-Cu. These alloys are slightly cheaper than pure Pd and more stable. Pd-25% silver is also slightly more permeable to hydrogen than pure Pd is — a win-win-win for the alloy.
There was a major advance in nuclear fusion this month at the The National Ignition Facility of Lawrence Livermore National Laboratory (LLNL), but the press could not figure out what it was, quite. They claimed ignition, and it was not. They claimed that it opened the door to limitless power. It did not. Some heat-energy was produced, but not much, 2.5 MJ was reported. Translated to the English system, that’s 600 kCal, about as much heat in a “Big Mac”. That’s far less energy went into lasers that set the reaction off. The importance wasn’t the amount in the energy produced, in my opinion, it’s that the folks at LLNL fired off a small hydrogen bomb, in house, and survived the explosion. 600 kCal is about the explosive power of 1.5 lb of TNT.
Many laser beams converge on a droplet of deuterium-tritium setting off the explosion of a small fraction of the fuel. The explosion had about the power of 1.2 kg of TNT. Drawing from IEEE Spectrum
The process, as reported in the Financial Times, involved “a BB-sized” droplet of holmium -enclosed deuterium and tritium. The folks at LLNL fast-cooked this droplet using 100 lasers, see figure of 2.1MJ total output, converging on one spot simultaneously. As I understand it 4.6 MJ came out, 2.5 MJ more than went in. The impressive part is that the delicate lasers survived the event. By comparison, the blast that bought down Pan Am flight 103 over Lockerbie took only 2-3 ounces of explosive, about 70g. The folks at LLNL say they can do this once per day, something I find impressive.
The New York Times seemed to think this was ignition. It was not. Given the size of a BB, and the density of liquid deuterium-tritium, it would seem the weight of the drop was about 0.022g. This is not much but if it were all fused, it would release 12 GJ, the equivalent of about 3 tons of TNT. That the energy released was only 2.5MJ, suggests that only 0.02% of the droplet was fused. It is possible, though unlikely, that the folks at LLNL could have ignited the entire droplet. If they did, the damage from 5 tons of TNT equivalent would have certainly wrecked the facility. And that’s part of the problem; to make practical energy, you need to ignite the whole droplet and do it every second or so. That’s to say, you have to burn the equivalent of 5000 Big Macs per second.
You also need the droplets to be a lot cheaper than they are. Today, these holmium capsules cost about $100,000 each. We will need to make them, one per second for a cost around $! for this to make any sort of sense. Not to say that the experiments are useless. This is a great way to test H-bomb designs without destroying the environment. But it’s not a practical energy production method. Even ignoring the energy input to the laser, it is impossible to deal with energy when it comes in the form of huge explosions. In a sense we got unlimited power. Unfortunately it’s in the form of H-Bombs.
This week, the Artemis I, Orion capsule splashed down to general applause after circling the moon with mannequins. The launch cost $4.1 Billion, and the project, $50 Billion so far, of $93 Billion expected. Artemis II will carry people around the moon, and Artemis III is expected to land the first woman and person of color. The goal isn’t one I find inspiring, and I feel even less inspired by the technology. I see few advances in Artemis compared to the Saturn V of 50 years ago. And in several ways, it looks like a step backwards.
The graphic below compares the Artemis I SLS (Space Launch System) to the Saturn V. The SLS is 10% lighter, but the payload is lighter, too. It can carry 27 tons to the moon, while the Saturn V sent 50 tons to the moon. I’d expect more weight by now. We have carbon fiber and aramids, and they did not. Add to this that the cost per flight is higher, $4.1 B, versus $1.49 B in 2022 dollars for a Saturn V ($185 million in 1969 dollars). What’s more there was no new engine development or production, so the flight numbers are limited: Each SLS launch throws away five, space shuttle engines. When they are all gone, the project ends. We have no plans or ability to make more engines.
Comparison of Apollo Saturn V and Artemis SLS. The SLS has less lift weight and costs more per launch.
As it happens, there was a better alternative available, the Falcon heavy from SpaceX. The Falcon heavy has been flying for 5 years now, and costs only $141 million per launch, about 1/30 as much as an Artemus launch. The rocket is largely reusable, with 3D printed engines, and boosters that land on their tails. Each SLS is expensive because it’s essentially a new airplane built specially for each flight. Every part but the capsule is thrown away. Adding to the cost of SLS launches is the fuel; hydrogen, the same fuel as the space shuttle. Per energy it’s very expensive. The energy cost for the SLS boosters is high too, and the efficiency is low; each SLS booster costs $290M, more than the cost of two Falcon heavy launches. Falcon launches are cheap, in part because the engines burn kerosine, as did the Saturn V at low altitude. Beyond cost hydrogen has low thrust per flow (low momentum), and is hard to handle; hydrogen leaks caused two Artemis scrubs, and numerous Shuttle delays. I discussed the physics of rocket engines in a post seven years ago.
This graph of $/kg to low earth orbit is mostly from futureblind.com. I added the data for Artemis SLS. Saturn V and Falcon use cheaper fuel and a leaner management team.
It might be argued that Artemis SLS is an inspirational advance because it can lift an entire moon project in one shot, but the Saturn V lifted that and more, all of Skylab. Besides, there is no need to lift everything on one launch. Elon Musk has proposed lifting in two stages, sending the moon rocket and moon lander to low earth orbit with one launch, then lifting fuel and the astronauts on a second launch. Given the low cost of a Falcon heavy launch, Musk’s approach is sure to save money. It also helps develop space refueling, an important technology.
Musk’s Falcon may still reach the moon because NASA still needs a moon lander. NASA has awarded the lander contract to three companies for now, Jeff Bezos’s Blue Origin, Dynetics-Aerodyne makers of the Saturn V, and Musk’s SpaceX. If the SpaceX version wins, a modified Falcon will be sent to the moon on a Falcon heavy along with a space station. Artemis III will rendezvous with them, astronauts will descend to the moon on the lander, and will use the lander to ascend. They’ll then transfer to an Orion capsule for the return journey. NASA has also contracted with Bezos’s Blue origin for planetary, Earth observation, and exploration plans. I suspect that Musk’s lander will win, if only because of reliability. There have been 59 Falcon launches this year, all of them with safe landings. By contrast, no Blue Origin or Dynetics rocket has landed, and Blue Origin does not expect to achieve orbital velocity till 2025.
As best I can tell, the reason we’re using the Artemis SLS with its old engines is inspiration. The Artemis program director, Charlie Blackwell-Thompson is female, and an expert in space shuttle engines. Previous directors were male. Previous astronauts too were mostly male. Musk is not only male, but his products suffer from him being considered a horrible person, a toxic male, in the Tony Stark (Iron Man) mold. Even Jeff Bezos and Richard Branson are considered better, though their technology is worse. See my comparison of SpaceX, Virgin Blue, and Blue Origin.
To me, the biggest blocks to NASA’s inspirational aims, in my opinion, are the program directors who gave us the moon landing. These were two Nazi SS commanders (SS Sturmbannführers), Arthur Rudolph and Wernher Von Braun. Not only were they male and white, they were barely Americanized Nazis, elevated to their role at NASA after killing off virtually all of their 20,000, mostly Jewish, slave workers making rockets for Hitler. Here’s a song about Von Braun, by Tom Lehrer. Among those killed was Von Braun’s professor. In his autobiography, Von Braun showed no sign of regret for any of this, nor does he take blame. The slave labor camp they ran, Dora-Mittelbau, had the highest death rate of all slave labor camps, and when some workers suggested that they could work better if they were fed, the directors, Rudolph and Von Braun had 80 machine gunned to death. Still, Von Braun got us to the moon, and his inspirational comments line the walls at NASA, Kennedy. Blackwell-Thompson and Bezos are surely more inspirational, but their designs seem like dead ends. We may still have to use Musk’s SpaceX if we want a lander or a moon program after the space shuttle’s engines are used up. As Von Braun liked to point out, “Sacrifices have to be made.”
My favorite fuel cells burn hydrogen-rich hydrocarbon fuels, like methane (natural gas) instead of pure hydrogen. Methane is far more energy dense, and costs far less than hydrogen per energy content. The US has plenty of methane and has pipelines that distribute it to every city and town. It’s a low CO2 fuel, and we can lower the CO2 impact further by mixing in hydrogen to get hythane. Elon Musk has called hydrogen- powered fuel cells “fool cells”, methane-powered fuel cells look a lot less foolish. They easily compete with his batteries and with gasoline. Besides, Musk has chosen methane as the fuel for his proposed starship to Mars.
Solid oxide fuel cells, SOFCs, can use methane directly without any pre-reformer. They operate at 800°C or so. At these temperatures, methane reacts with water (steam) within the fuel cell to form hydrogen by the reaction, CH4 + H2O –> 3H2 + CO. The hydrogen, and to a lesser extent the CO is oxidized in the fuel cell to create electricity,, but the methane is not 100% consumed, generally. Unused methane, CO, and some hydrogen exits a solid oxide fuel cell along with the products of combustion, CO2 and water.
Several researchers have looked for ways to recycle this waste fuel to capture the energy value. Six years ago, I patented a membrane method to extract the waste fuel and recycle it, see a description here. I now see this method as too complex, and have applied for a patent on a simpler version, shown below as Figure 1. As before the main work is done by a membrane but here I dispense with the water gas shift reactor, and many of the heat exchangers of the previous approach.
Simple way to improve fuel use in a high temperature fuel cell, using just a membrane.
The fuel cell system of Fig. 1 operates at somewhat elevated pressure, 2 atm or more. It is expected that the majority of the exhaust going to the membrane will be CO2 and water. Most of this will pass through the membrane and will exhaust to the air. The rest is mixed with fresh methane and recycles to the fuel cell. Despite the pressure of the fuel cell, very a little energy is needed for recirculation since the methane does not go through the membrane. The result is a light, simple, and energy efficient process. If you are interested, please contact me at REB Research. Or you can purchase the silicone membrane module here. Alternately, see here for flux information and other applications.
It’s good to have hero, someone whose approach to life, family and business you admire that you might reasonably be able to follow. As an engineer, inventor, I came to regard Peter Cooper of New York as a hero. He made his own business and was a success, in business and with his family without being crooked. This is something that is not as common as you might think. When I was in 4th grade, we got weekly assignments to read a biography and write about it. I tended to read about scientists and inventors then and after. I quickly discovered that successful inventors tended to die broke, estranged from their family and friends. Edison, Tesla, Salk, Goodyear, and Ford are examples. Tesla didn’t marry. Henry Ford’s children were messed up. Salk had a miserable marriage. Almost everyone working on the Atom Bomb had issues with the government. Most didn’t benefit financially. They died hated by the press as mass-murderers, and pursued by the FBI as potential spies. It was a sad pattern for someone who hoped to be an inventor -engineer.
The one major exception I found was Peter Cooper, an inventor, industrialist, and New York politician who was honest, and who died wealthy and liked with a good family. One result of reading about him was to conclude that some engineering areas are better than others; generally making weapons is not a path to personal success.
Tom Thumb, the blower at right is the secret to its light weight per power.
Peter Cooper was different, both in operation and outcome. Though he made some weapons (gun barrels) and inverted a remote control torpedo, these were not weapons of mass killing. Besides he but thee for “the good side” of the Civil War. And, when Cooper made an invention or a product, he made sure to have the capital available to make a profit on it too. He worked hard to make sure his products were monopolies, using a combination of patents and publicity to secure their position.
Brand management helps.
Cooper was a strong family man who made sure to own his own business, and made sure to control the sources of key materials too. He liked to invest in other businesses, but only as the controlling share-holder, or as a bond holder, believing that minor share-holders tend to be cheated. He was pro monopoly, pro trusts, and a big proponet of detailed contracts, so everyone knew where they stood. A famous invention of Cooper’s was Jello, a flavored, light version of his hide-glue, see the patent here. Besides patenting it, he sold the product with his brand, thus helping to maintain the monopoly.
Cooper was generous with donations to the poor, but not to everyone, and not with loans. And he would not sign anyone’s note as a guarantor. Borrowers tended to renege, he found, and they resent you besides. You lose your money, and lost them as a friend. He founded two free colleges, Cooper Union, and the Cooper-Limestone Institute, plus an inventor’s institute. (I got my education, free from Cooper Union.) Cooper ran these institutions in his lifetime, not waiting till he was dead to part with his money. Many do this in the vain hope that others will run the institution as they would.
Peter Cooper always sought a monopoly, or a near monopoly, patenting his own inventions, or buying the rights to others’ patents to help make it so. He believed that monopolies were good, saying they were the only sort of business that made money while allowing him to treat his workers well. If an invention would not result in a monopoly, Peter Cooper gave the rights away.
The list of inventions he didn’t patent include the instruments to test the quality of glue and steel (quality control is important), and a tide-powered ferry in New York. Perhaps his most famous unpainted invention was a lightweight, high power steam locomotive, “The Tom Thumb”, made in 1840. Innovations included beveled wheels to center the carriage on its rails, and a blower on the boiler fire, see photo above. The blower meant he could generate high-power in a small space at light weight. These are significant innovations, but Cooper did not foresee having a monopoly, so he didn’t pursue these ideas. Instead, he focussed on making rails and wire rope; he patented the process to roll steel, and the process for making coke from coal. Also on his glue/jello business. Since he made these items from dead cows and horses, he found he could also sell “foot oil” and steam-pounded leather, “Chamois”. He also pursued a telephone/ telegraph business across the Atlantic, more on that below, but only after getting monopoly rights for 50 years.
Cooper managed to stay friends with those he competed with by paying license fees for any patents he used (he tried to negotiate low rates), or buying or selling the patent rights as seemed appropriate. He also licensed his patents, and rented out buildings he didn’t need. He rented at a rate of 7% of the sale price, a metric I’ve used myself, considering rental to be like buying on loan. There is a theory of stock-buying that matches this.
The story the telegraph cable across the Atlantic is instructive to seeing how the pieces fit together. The first significant underwater cable was not laid by Cooper, by a Canadian inventor, Frederick Gisborne. It was laid in 1852 between Prince Edward Island and New Brunswick. Through personal connections, Gisborne’s company got exclusive rights for 30 years, for this and for a cable that would go to Newfoundland, but he didn’t have the money or baking to make it happen. The first cable failed, and Gisborne ran out of money and support. Only his exclusive rights remained. This is the typical story of an inventor/ engineer/businessman who has to rely on other peoples’ money and patience.
A few months after the failure, a friend of Cooper’s, Cyrus Field, convinced Cooper that good money could be made, and public good could be done, if Cooper could lay such a cable all the way to London. One thing that attracted Cooper to the project was that the cable could be made as an insulated iron-copper rope in Cooper’s own factory. Cooper, Field, and some partners (see painting below) bought Gisborne’s company, along with their exclusive rights, and formed a new company, The New York, Newfoundland & London Telegraph Company, see charter here. The founders are imagined* with a globe and a section of cable sitting on their table. Gisborne, though not shown in the painting, was a charter member, and made chief engineer. Cooper was president. He also traveled on the boat with Gisborne to lay the cable across the St. Lawrence – just to be sure he knew what was going on. This cable provided a trial for The Trans Atlantic cable.
The founding individuals to lay a transatlantic cable. Peter Cooper at left is the chairman, Cyrus Field is standing, Samuel Morse is at the back. Frederic Gisborne, a founder, does not appear in the paining. Typical.
Samuel Morse was hired as an electrician; he is pictured in the painting, but was not a charter member. Part of the problem with Morse was that he owned the patent on Morse-telegraphy, and Cooper didn’t want to pay his “exorbitant” fees. So Cooper and Field bought an alternative telegraph patent from David Hughes, a Kentucky school teacher. This telegraph system used tones instead of clicks and printed whole letters at a time. By hiring Morse, but not his patents, Cooper saved money, while retaining Morse’s friendship and expertise. The alternative could have been a nasty spat. Their telegraph company sub-licensed Hughes’s tone-method a group of western telegraph owners, “The Western Union,” who used it for many years, producing the distinctive Western Union Telegrams. With enough money in hand and credibility from the Canadian trial, the group secured 50 years monopoly rights for a telegraph line across the Atlantic. Laying the cable took many years, with semi-failed attempts in 1857, 1858, and 1865. When the eventual success came in 1866, the 50 years’ monopoly rights they’d secured meant that they made money from the start. They could treat workers fairly. Marconi would discover that Cooper wrote a good contract; his wireless telegraph required a widely different route.
I should also note that Peter Cooper was politically active: he started as a Democrat, helped form the Republican Party, bringing Lincoln to speak in NY for the first time, and ended up founding the Greenback-Labor Party, running for president as a Greenback. He was strongly for tariffs, and strongly against inflation. He said that the dollar should have the same value for all time for the same reason that the foot should have the same length and the pound the same weight. I have written in favor of tariffs off and on. They help keep manufacturing in America, and help insure that those who require French wine or German cars pay the majority of US taxes. They are also a non-violent vehicle for foreign policy.
Operating under these principles, through patents and taxed monopolies, Peter Cooper died wealthy, and liked. Liked by his workers, liked by much of the press, and by his family too, with children who turned out well. The children of rich people often turn out poorly. Carnegie’s children fought each other in court, Ford’s were miserable. Cooper’s children continued in business and politics, successfully and honorably, and in science/ engineering (Peter Coper Hewitt invented the power rectifier, sold to Westinghouse). The success of Peter Cooper’s free college, Cooper Union, influenced many of his friends to open similar institutions. Among his friends who did this were Carnegie, Pratt, Stevens, Rensselaer, and Vanderbilt. He stayed friends with them and with other inventors of the day, despite competing in business and politics. Most rich folks can not do this; they tend to develop big egos, and few principles.
Robert Buxbaum, November 30, 2022. I find the painting interesting. Why was it painted? Why is Gisborne not in it and Morse in the painting — sometimes described as vice President? The charter lists Morse as “electrician”, an employee. Chandler White, holding papers next to Cooper, was Vice President. My guess is that the painting was made to help promote the company and sell stock. They made special cigars with this image too. This essay started as a 5th grade project with my son. See a much earlier version here.
MY home-made still, and messy lab. Note the masking tape seal and the nylon hoses. Nylon is cheaper than copper. The yellow item behind the burner is the cooling water circulation pump. The wire at top and left is the thermocouple.
I have an apple tree, a peach tree, and some grape vines. They’re not big trees, but they give too much fruit to eat. The squirrels get some, and we give some away. As for the rest, I began making wine and apple jack a few years back, but there’s still more fruit than I can use. Being a chemical engineer, I decided to make brandy this year, so far only with pears and apples.
The first steps were the simplest: I collected fruit in a 5 gallon, Ace bucket, and mashed it using a 2×4. I then added some sugar and water and some yeast and let it sit with a cover for a week or two. Bread yeast worked fine for this, and gives a warm flavor, IMHO. A week or so later, I put the mush into a press I had fro grapes, shown below, and extracted the fermented juice. I used a cheesecloth bag with one squeezing, no bag with the other. The bag helped, making cleanup easier.
The fruit press, used to extract liquid. A cheese cloth bag helps.
I did a second fermentation with both batches of fermented mash. This was done in a pot over a hot-plate on warm. I added more sugar and some more yeast and let it ferment for a few more days at about 78°F. To avoid bad yeasts, I washed out the pot and the ace bucket with dilute iodine before using them– I have lots of dilute iodine around from the COVID years. The product went into the aluminum “corn-cooker” shown above, 5 or 6 gallon size, that serves as the still boiler. The aluminum cover of the pot was drilled with a 1″ hole; I then screwed in a 10″ length of 3/4″ galvanized pipe, added a reducing elbow, and screwed that into a flat-plate heat exchanger, shown below. The heat exchanger serves as the condenser, while the 3/4″ pipe is like the cap on a moonshiner still. Its purpose is to keep the foam and splatter from getting in the condenser.
I put the pot on the propane burner stand shown, sealed the lid with masking tape (it worked better than duct tape), hooked up the heat exchanger to a water flow, and started cooking. If you don’t feel like making a still this way, you can buy one at Home Depot for about $150. Whatever route you go, get a good heat exchanger/ condenser. The one on the Home-depot still looks awful. You need to be able to take heat out as fast as the fire puts heat in, and you’ll need minimal pressure drop or the lid won’t seal. The Home Depot still has too little area and too much back-pressure, IMHO. Also, get a good thermometer and put it in the head-space of the pot. I used a thermocouple. Temperature is the only reasonable way to keep track of the progress and avoid toxic distillate.
A flat-plate heat exchanger, used as a condenser.
The extra weight of the heat exchanger and pipe helps hold the lid down, by the way, but it would not be enough if there was a lot of back pressure in the heat exchanger-condenser. If your lid doesn’t seal, you’ll lose your product. If you have problems, get a better heat exchanger. I made sure that the distillate flows down as it condenses. Up-flow adds back pressure and reduces condenser efficiency. I cooled the condenser with water circulated to a bucket with the cooling water flowing up, counter current to the distillate flow. I could have used tap water via a hose with proper fittings for cooling, but was afraid of major leaks all over the floor.
With the system shown, and the propane on high, it took about 20 minutes to raise the temperature to near boiling. To avoid splatter, I turned down the heater as the temperature approached 150°F. The first distillate came out at 165°F, a temperature that indicated it was not alcohol or anything you’d want to drink. I threw away the first 2-3 oz of this product. You can sniff or sip a tiny amount to convince yourself that this this is really nasty, acetone, I suspect, plus ethyl acetate, and maybe some ether and methanol. Throw it away!
After the first 2-3 ounces, I collected everything to 211°F. Product started coming in earnest at about 172°F. I ended distillation at 211°F when I’d collected nearly 3 quarts. For my first run, my electronic thermometer was off and I stopped too early — you need a good thermometer. The material I collected and was OK in taste, especially when diluted a bit. To test the strength, I set some on fire, the classic “100% proof test”, and diluted till it to about 70% beyond. This is 70% proof, by the classic method. I also tried a refractometer, comparing the results to whiskey. I was aiming for 60-80 proof (30-40%).
My 1 gallon aging barrel.
I tried distilling a second time to improve the flavor. The result was stronger, but much worse tasting with a loss of fruit flavor. By contrast, a much better resulted from putting some distillate (one pass) in an oak barrel we had used for wine. Just one day in the barrel helped a lot. I’ve also seen success putting charred wood cubes set into a glass bottle of distillate. Note: my barrel, as purchased, had leaks. I sealed them with wood glue before use.
I only looked up distilling law after my runs. It varies state to state. In Michigan, making spirits for consumption, either 1 gal or 60,000 gal/year, requires a “Distilling, Rectifying, Blending and/or Bottling Spirits” Permit, from the ATF Tax and Trade Bureau (“TTB”) plus a Small Distiller license from Michigan. Based on the sale of stills at Home Depot and a call to the ATF, it appears there is little interest in pursuing home distillers who do not sell, despite the activity being illegal. This appears similar to state of affairs with personal use marijuana growers in the state. Your state’s laws may be different, and your revenuers may be more enthusiastic. If you decide to distill, here’s some music, the Dukes of Hazard theme song.
In terms of raw strength though, pounds/in2, wood is not particularly strong, only about 7000 psi (45MPa) both in tension and compression, about half the strength of aluminum. It is thus not well suited to supporting heavy structures, like skyscrapers. (I calculate the maximum height of a skyscraper here), but wood can be modified to make it stronger by removing most of the air, and replacing it with plastic. The result is a stronger, denser, flexible composite, that is typically transparent. The flower below is seen behind a sheet of transparent wood.
A picture of a flower taken through a piece of transparent super-wood.
To make a fairly strong, transparent wood, you take ordinary low-density wood (beech or balsa are good) and soak it in alkali (NaOH). This bleaches the wood, softens the cellulose, and dissolves most of the lignin. You next wash off the alkali and soak the wood in a low viscosity epoxy or acrylic. Now, put it in a vacuum chamber to remove the air — you’ll need a brick to hold the wood down in the liquid. You’ll see bubbles in the epoxy as the air leaves. Then, when the vacuum is released, the wood soaks up the epoxy or acrylic. On curing, you get a composite strong and transparent, but not super strong.
To make the wood really strong, super-strong, you need to compress the uncured, epoxy soaked wood. One method is to put it in a vice. This drives off more of the air and further aligns the cellulose fibers. You now cure it as before (you need a really slow cure epoxy or a UV-cure polymer). The resultant product have been found to have tensile strengths as high as 270 MPa in the direction of alignment, over 40,000 psi. This is three times stronger than regular aluminum, 90 MPa, (13,500 psi). It’s about the strength of the strongest normal aluminum alloy, 6061. It’s sort of expensive to make, but it’s flexible and transparent, making it suitable for space windows and solar cells. It’s the lightest flexible transparent material known. It’s biodegradable, and that’s very cool, IMHO. See here for a comparison with other, high strength, transparent composites.
Robert Buxbaum, November 10, 2022. I think further developments along this line would make an excellent high school science fair project, college thesis, or PhD research project. Compare different woods, or epoxies, different alkalis, and temperatures, or other processing ideas. How strong and transparent can you make this material, or look at other uses. Can you use it for roof solar cells, like Musk’s but lighter, or mold it for auto panels, it’s already lighter and stronger, or use it as bullet-proof glass or airplane windows.
Sharrow Marine introduced a new ship propeller design two years ago, at the Miami International Boat show. Unlike traditional propellers, there are no ends on the blades. Instead, each blade is a connecting ribbon with the outer edge behaving like a connecting winglet. The blade pairs provide low-speed lift-efficiency gains, as seen on a biplane, while the winglets provide high speed gains. The efficiency gain is 9-30% over a wide range of speeds, as shown below, a tremendous improvement. I suspect that this design will become standard over the next 10-20 years, as winglets have become standard on airplanes today.
A Sharrow propeller, MX-1
The high speed efficiency advantage of the closed ends of the blades, and of the curved up winglets on modern airplanes is based on avoiding losses from air (or water) going around the end from the high pressure bottom to the low-pressure top. Between the biplane advantage and the wingtip advantage, Sharrow propellers provide improved miles per gallon at every speed except the highest, 32+ mph, plus a drastic decrease in vibration and noise, see photo.
The propeller design was developed with paid research at the University of Michigan. It was clearly innovative and granted design patent protection in most of the developed world. To the extent that the patents are respected and protected by law, Sharrow should be able to recoup the cost of their research and development. They should make a profit too. As an inventor myself, I believe they deserve to recoup their costs and make a profit. Not all inventions lead to a great product. Besides, I don’t think they charge too much. The current price is $2000-$5000 per propeller for standard sizes, a price that seems reasonable, based on the price of a boat and the advantage of more speed, more range, plus less fuel use and less vibration. This year Sharrow formed an agreement with Yamaha to manufacture the propellers under license, so supply should not be an issue.
Vastly less turbulence follows the Sharrow propeller.
China tends to copy our best products, and often steals the technology to make them, employing engineers and academics as spys. Obama/Biden have typically allowed China to benefit for the sales of copies and the theft of intellectual property, allowing the import of fakes to the US with little or no interference. Would you like a fake Rolex or Fendi, you can buy on-line from China. Would you like fake Disney, ditto. So far, I have not seen Chinese copies of the Sharrow in the US, but I expect to see them soon. Perhaps Biden’s Justice Department will do something this time, but I doubt it. By our justice department turning a blind eye to copies, they rob our innovators, and rob American workers. His protectionism is one thing I liked about Donald Trump.
The Sharrow Propeller gives improved mpg values at every speed except the very highest.
Electric vehicles work well for short trips between places where you can charge with cheap electricity. Typically that’s trips from home to a nearby place of work, and to local shopping malls and theaters with low-cost charge spots. If you drive this way, you’ll pay about 3.2¢/mile for home electricity, instead of about 17¢/mile for gasoline transport (e.g. 24 mpg with $4/gallon gas). Using an EV also saves on oil changes, transmission, air filters, belts, etc., and a lot of general complexity. Battery prices are still high, but much lower than they were even a few years ago.
The 10 kW Aquarius Engine is remarkably small and light, about 10kg (22 lb).
EVs are less attractive for long trips, especially in the cold. Your battery must provide the heat, as there is no waste heat from the engine. Expect to have to recharge every 200 -250 miles, or perhaps twice in the middle of a long trip. Each charge will take a half-hour or more, and fast charging on the road isn’t low cost. Expect to pay about 15¢/mile, nearly as much as for gasoline. See my full comparison of the economics here.
One obvious solution is to have two cars: a short commuter and an EV. Another solution is a hybrid. The Toyota’s Prius and the Chevy Volt were cutting edge in their day, but people don’t seem to want them. These older hybrids provided quick fill-ups, essentially infinite range, and about double the gas milage of a standard automobile, 30-45 mpg. The problem is you have even more complexity and maintenance than with even a gas automobile.
Aquarius liner engine as a range extender
I recently saw a small, simple, super-efficient (they say) gas engine called Aquarius. It provides 9.5 kW electric output and weighs only 22 lbs (10 kg), see picture above. A Tesla S uses about 16 kW during highway driving, implying that this engine will more than double the highway range of a Tesla S at minimal extra weight and complexity. It also removes the fear of being stranded on the highway, far from the nearest charge-station.
The energy efficiency is 34%, far higher than that for normal automobile engines, but fairly typical of floating piston linear engines. The high efficiency of these engines is partly due to the lack of tapper valves, risers, crank-shaft, and partially due to the fact that the engine always runs at its maximum power. This is very close to the maximum efficiency point. Most car engines are over sized (200 hp or so) and thus must run at a small fraction of their maximum power. This hurts the efficiency, as I discuss here. The Aquarius Engine makes electricity by the back-forth motion of its aligner rods moving past magnetic stator coils. Slots in the piston rod and in the side of the cylinder operate as sliding valves, like in a steam engine. First versions of the Aquarius Engine ran on hydrogen, but the inventors claim it can also run on gasoline, and presumably hythane, my favorite fuel, a mix of hydrogen and natural gas.
At the moment shown, slit valves in the piston rod are open to both cylinder chambers. The explosion at left will vent to the exhaust at left and out the manifold at top. The sliding valve is currently sending fresh air into the cylinder at right, but will soon send it into both cylinders to help scavenge exhaust and provide for the next cycle; engine speed and impression are determined by the mass of the piston.
A video is available to show the basic operation (see it here). The drawing at right is from that video, modified by me. Air is drawn into the engine through a sliding valve at the middle of the cylinder. The valve opens and closes depending on where the piston is. At the instant shown in the picture, the valve is open to the right. Air enters that chambered is likely exiting through slits in the hollow piston rod. It leaves through the manifold t the top, pushing exhaust along with it. When the piston will have moved enough, both the slits and the intake will close. The continued piston motion (inertially driven) will compress the air for firing. After firing, the piston will move left, generating electricity, and eventually opening the slit-valve in the piston to allow the exhaust to leave. When it moves a little further the intake will open.
The use of side-opening exhaust valves is a novelty of the “Skinner UniFlow” double-acting, piston steam engines, seen on the Badger steamship on Lake Michigan. It’s one of my favorite steam engine designs. Normally you want a piston that is much thicker than the one in the drawing. This option is mentioned in the patent, but not shown in the drawing.
Aquarius is not the only company with a free-piston range extender. Toyota built a free-piston extender of similar power and weight; it was more complex but got higher efficiency. It has variable compression though, and looks like a polluter. (the same problems might affect the Aquarius) They dropped the project in 2014. Deutsch Aerospace has a two headed version that’s more powerful, but long and heavier: 56kg and 35kW. Lotus has a crank-piston engine, also 56kg, 35kW; it’s more complex and may have service life issues, but it’s compact and relatively light, and it probably won’t pollute. Finally, Mazda is thinking of bringing back its Wankel rotary engine as a range extender. Any of these might win in the marketplace, but I like the Aquarius engine for its combination of light weight, compact size, and simplicity.
This is not to say that Aquarius motors is a good investment. Aquarius automotive went public on the Toronto exchange in December, 2021, AQUA.TA. The company has no profits to date, and the only chance of them making a profit resides in them getting a good licensing deal from an established company. The major car companies have shown no interest so far, though they clearly need something like this. Their plug in hybrids currently use standard-size, 4 stroke engines: 110-150 kW, 100-150 kg, complex, and low efficiency. Consumers have not been impressed. Tesla autos could benefit from this engine, but Musk shows no interest either.
Robert Buxbaum May 5, 2022. I have no stock in Aquarius motors, nor have I received any benefits from them, or any auto company.
There are two ASTM-approved methods for measuring the gas permeability of a material. The equipment is very similar, and REB Research makes equipment for either. In one of these methods (described in detail here) you measure the rate of pressure rise in a small volume.This method is ideal for high permeation rate materials. It’s fast, reliable, and as a bonus, allows you to infer diffusivity and solubility as well, based on the permeation and breakthrough time.
Exploded view of the permeation cell.
For slower permeation materials, I’ve found you are better off with the other method: using a flow of sampling gas (helium typically, though argon can be used as well) and a gas-sampling gas chromatograph. We sell the cells for this, though not the gas chromatograph. For my own work, I use helium as the carrier gas and sampling gas, along with a GC with a 1 cc sampling loop (a coil of stainless steel tube), and an automatic, gas-operated valve, called a sampling valve. I use a VECO ionization detector since it provides the greatest sensitivity differentiating hydrogen from helium.
When doing an experiment, the permeate gas is put into the upper chamber. That’s typically hydrogen for my experiments. The sampling gas (helium in my setup) is made to flow past the lower chamber at a fixed, flow rate, 20 sccm or less. The sampling gas then flows to the sampling loop of the GC, and from there up the hood. Every 20 minutes or so, the sampling valve switches, sending the sampling gas directly out the hood. When the valve switches, the carrier gas (helium) now passes through the sampling loop on its way to the column. This sends the 1 cc of sample directly to the GC column as a single “injection”. The GC column separates the various gases in the sample and determines the components and the concentration of each. From the helium flow rate, and the argon concentration in it, I determine the permeation rate and, from that, the permeability of the material.
As an example, let’s assume that the sample gas flow is 20 sccm, as in the diagram above, and that the GC determines the H2 concentration to be 1 ppm. The permeation rate is thus 20 x 10-6 std cc/minute, or 3.33 x 10-7 std cc/s. The permeability is now calculated from the permeation area (12.56 cm2 for the cells I make), from the material thickness, and from the upstream pressure. Typically, one measures the thickness in cm, and the pressure in cm of Hg so that 1 atm is 76cm Hg. The result is that permeability is determined in a unit called barrer. Continuing the example above, if the upstream hydrogen is 15 psig, that’s 2 atmospheres absolute or or 152 cm Hg. Lets say that the material is a polymer of thickness is 0.3 cm; we thus conclude that the permeability is 0.524 x 10-10 scc/cm/s/cm2/cmHg = 0.524 barrer.
This method is capable of measuring permeabilities lower than the previous method, easily lower than 1 barrer, because the results are not fogged by small air leaks or degassing from the membrane material. Leaks of oxygen, and nitrogen show up on the GC output as peaks that are distinct from the permeate peak, hydrogen or whatever you’re studying as a permeate gas. Another plus of this method is that you can measure the permeability of multiple gas species simultaneously, a useful feature when evaluating gas separation polymers. If this type of approach seems attractive, you can build a cell like this yourself, or buy one from us. Send us an email to reb@rebresearch.com, or give us a call at 248-545-0155.
