Category Archives: Robert Buxbaum

A rotating disk bio-reactor for sewage treatment

One of the most effective designs for sewage treatment is the rotating disk bio-reactor, shown below. It is typically used in small-throughput sewage plants, but it performs quite well in larger plants too. I’d like to present an analysis of the reactor, and an explanation of why it works so well.

A rotating disc sewage reactor.

A rotating disk sewage reactor; ∂ is the thickness of the biofilm. It’s related to W the rotation rate in radians per sec, and to D the limiting diffusivity.

As shown, the reactor is fairly simple-looking, nothing more than a train of troughs filled with sewage-water, typically 3-6 feet deep, with a stack of discs rotating within. The discs are typically 7 to 14 feet in diameter (2-4 meters) and 1 cm apart. The shaft is typically close to the water level, but slightly above, and the rotation speed is adjustable. The device works because appropriate bio-organisms attach themselves to the disk, and the rotation insures that they are fully (or reasonably) oxygenated.

How do we know the cells on the disc will be oxygenated? The key is the solubility of oxygen in water, and the fact that these discs are only used on the low biological oxygen demand part of the sewage treatment process, only where the sewage contains 40 ppm of soluble organics or less. The main reaction on the rotating disc is bio oxidation of soluble carbohydrate (sugar) in a layer of wet slime attached to the disc.

H-O-C-H + O2 –> CO2 + H2O.

As it happens, the solubility of pure oxygen in water is about 40 ppm at 1 atm. As air contains 21% oxygen, we expect an 8 ppm concentration of oxygen on the slime surface: 21% of 40 ppm = 8 ppm. Given the reaction above and the fact that oxygen will diffuse five times more readily than sugar at least, we expect that one disc rotation will easily provide enough oxygen to remove 40 ppm sugar in the slime at every speed of rotation so long as the wheel is in the air at least half of the time, as shown above.

Let’s now pick a rotation speed of 1/3 rpm (3 minutes per rotation) and see where that gets us in terms of speed of organic removal. Since the disc is always in an area of low organic concentration, it becomes covered mostly with “rotifers”, a fungus that does well in low nutrient (low BOD) sewage. Let’s now assume that mass transfer (diffusion) of sugar in the rotifer slime determines the thickness of the rotifera layer, and thus the rate of organic removal. We can calculate the diffusion depth of sugar, ∂ via the following equation, derived in my PhD thesis.

∂ = √πDt

Here, D is the diffusivity (cm2/s) for sugar in the rotifera slime attached to the disk, π = 3.1415.. and t is the contact time, 90 seconds in the above assumption. My expectation is that D in the rotifer slime will be similar to the diffusivity sugar in water, about 3 x 10-6 cm2/s. Based on the above, we find the rotifer thickness will be ∂ = √.00085 cm2 = .03 cm, and the oxygen depth will be about 2.5 times that, 0.07 cm. If the discs are 1 cm apart, we find that, about 14% of the fluid volume of the reactor will be filled with slime, with 2/5 of this rotifer-filled. This is as much as 1000 times more rotifers than you would get in an ordinary constantly stirred tank reactor, a CSTR to use a common acronym. We might now imagine that the volume of this sewage-treatment reactor can be as small as 1000 gallons, 1/1000 the size of a CSTR. Unfortunately it is not so; we’ll have to consider another limiting effect, diffusion of nutrients.

Consider the diffusive mass transfer of sugar from a 1,000,000 gal/day flow (43 liters/sec). Assume that at some point in the extraction you have a concentration C(g/cc) of sugar in the liquid where C is between 40 ppm and 1 ppm. Let’s pick a volume of the reactor that is 1/20 the normal size for this flow (not 1/1000 the size, you’ll see why). That is to say a trough whose volume is 50,000 gallons (200,000 liters, 200 m3). If the discs are 1 cm apart, this trough (or section of a trough) will have about  4×10^8 cm2 of submerged surface, and about 9×10^8 total surface including wetted disc in the air. The mass of organic that enters this section of trough is 44,000 C g/second, but this mass of sugar can only reach the rotifers by diffusion through a water-like diffusion layer of about .06 cm thickness, twice the thickness calculated above. The thickness is twice that calculated above because it includes the supernatant liquid beyond the slime layer. We now calculate the rate of mass diffusing into the disc: AxDxc/z = 8×10^8 x 3×10-6 x C/.06 cm = 40,000 C g/sec, and find that, for this tank size and rotation speed, the transfer rate of organic to the discs is 2/3 as much as needed to absorb the incoming sugar. This is to say that a 50,000 gallon section is too small to reduce the concentration to ln (1) at this speed of disc rotation.

Based on the above calculation, I’m inclined to increase the speed of rotation to .75 rpm. At this speed, the rotifer-slime layer will be 2/3 as thin 0.2 mm, and we expect an equally thinner diffusion barrier in the supernatant. At this faster speed, there is now 3/2 as much diffusion transfer per area because the thinner diffusion barrier, and we can expect a 50,000 liter reactor section to reduce the initial concentration by a fraction of 1/2.718 or C/e. Note that the mass transfer rate to the discs is always proportional to C. If we find that 50,000 gallons of tank reduces the concentration to 1/e, we find that we need 150,000 gallons of reactor to reduce the concentration of sugar from 40 ppm to 2 ppm, the legal target, ln (40/2) = 3. This 150,000 gallons is a remarkably small volume to reduce the sBOD concentration from 40 ppm to 2 ppm (sBOD = soluble biological oxygen demand), and the energy use is small too if the disc bearings are good.

The Holly sewage treatment plant is the only one in Oakland county, MI using the rotating disc contacted technology. It has a flow of 1,000,000 gallons per day, and has a contactor trough that is 215,000 gallons, about what we’d expect though their speed is somewhat higher, over 1 rpm and their input concentration is likely lower than 40 ppm. For the first stage of sewage treatment, the Holly plant use a vertical-draft, trickle-bed reactor. That is they drizzle the sewage-liquids over a slime-coated packing to reduce the sBOD concentration from 200 ppm to before feeding the flow to the rotating discs. My sense of the reason they don’t do the entire extraction with a trickle bed is that the discs use far less energy.

I should also add that the back-part of the disc isn’t totally useless oxygen storage, as it seems from my analysis. Some non-sugar reactions take place in the relatively anoxic environment there and in the liquid at the bottom of the trough. In these regions, iron reacts with phosphate, and nitrate removal takes place. These are other important requirements of sewage treatment.

Robert E. Buxbaum, July 18, 2017. As an exercise, find the volume necessary for a plug flow reactor or a stirred tank reactor (CSTR) to reduce the concentration of sugar from 40 ppm to 2 ppm. Assume 1,000,000 gal per day, an excess of oxygen in these reactors, and a first order reaction with a rate constant of dC/dt = -(0.4/hr)C. At some point in the future I plan to analyze these options, and the trickle bed reactor, too.

My latest invention: improved fuel cell reformer

Last week, I submitted a provisional patent application for an improved fuel reformer system to allow a fuel cell to operate on ordinary, liquid fuels, e.g. alcohol, gasoline, and JP-8 (diesel). I’m attaching the complete text of the description, below, but since it is not particularly user-friendly, I’d like to add a small, explanatory preface. What I’m proposing is shown in the diagram, following. I send a hydrogen-rich stream plus ordinary fuel and steam to the fuel cell, perhaps with a pre-reformer. My expectation that the fuel cell will not completely convert this material to CO2 and water vapor, even with the pre-reformer. Following the fuel cell, I then use a water-gas shift reactor to convert product CO and H2O to H2 and CO2 to increase the hydrogen content of the stream. I then use a semi-permeable membrane to extract the waste CO2 and water. I recirculate the hydrogen and the rest of the water back to the fuel cell to generate extra power, prevent coking, and promote steam reforming. I calculate the design should be able to operate at, perhaps 0.9 Volt per cell, and should nearly double the energy per gallon of fuel compared to ordinary diesel. Though use of pure hydrogen fuel would give better mileage, this design seems better for some applications. Please find the text following.

Use of a Water-Gas shift reactor and a CO2 extraction membrane to improve fuel utilization in a solid oxide fuel cell system.

Inventor: Dr. Robert E. Buxbaum, REB Research, 12851 Capital St, Oak Park, MI 48237; Patent Pending.

Solid oxide fuel cells (SOFCs) have improved over the last 10 years to the point that they are attractive options for electric power generation in automobiles, airplanes, and auxiliary power supplies. These cells operate at high temperatures and tolerate high concentrations of CO, hydrocarbons and limited concentrations of sulfur (H2S). SOFCs can operate on reformate gas and can perform limited degrees of hydrocarbon reforming too – something that is advantageous from the stand-point of fuel logistics: it’s far easier to transport a small volume of liquid fuel that it is a large volume of H2 gas. The main problem with in-situ reforming is the danger of coking the fuel cell, a problem that gets worse when reforming is attempted with the more–desirable, heavier fuels like gasoline and JP-8. To avoid coking the fuel cell, heavier fuels are typically reforming before hand in a separate reactor, typically by partial oxidation at auto-thermal conditions, a process that typically adds nitrogen and results in the inability to use the natural heat given off by the fuel cell. Steam reforming has been suggested as an option (Chick, 2011) but there is not enough heat released by the fuel cell alone to do it with the normal fuel cycles.

Another source of inefficiency in reformate-powered SOFC systems is basic to the use of carbon-containing fuels: the carbon tends to leave the fuel cell as CO instead of CO2. CO in the exhaust is undesirable from two perspectives: CO is toxic, and quite a bit of energy is wasted when the carbon leaves in this form. Normally, carbon can not leave as CO2 though, since CO is the more stable form at the high temperatures typical of SOFC operation. This patent provides solutions to all these problems through the use of a water-gas shift reactor and a CO2-extraction membrane. Find a drawing of a version of the process following.

RE. Buxbaum invention: A suggested fuel cycle to allow improved fuel reforming with a solid oxide fuel cell

RE. Buxbaum invention: A suggested fuel cycle to allow improved fuel reforming with a solid oxide fuel cell

As depicted in Figure 1, above, the fuel enters, is mixed with steam or partially boiled water, and heated in the rectifying heat exchanger. The hot steam + fuel mix then enters a steam reformer and perhaps a sulfur removal stage. This would be typical steam reforming except for a key difference: the heat for reforming comes (at least in part) from waste heat of the SOFC. Normally speaking there would not be enough heat, but in this system we add a recycle stream of H2-rich gas to the fuel cell. This stream, produced from waste CO in a water-gas shift reactor (the WGS) shown in Figure 1. This additional H2 adds to the heat generated by the SOFC and also adds to the amount of water in the SOFC. The net effect should be to reduce coking in the fuel cell while increasing the output voltage and providing enough heat for steam reforming. At least, that is the thought.

SOFCs differ from proton conducting FCS, e.g. PEM FCs, in that the ion that moves is oxygen, not hydrogen. As a result, water produced in the fuel cell ends up in the hydrogen-rich stream and not in the oxygen stream. Having this additional water in the fuel stream of the SOFC can promote fuel reforming within the FC. This presents a difficulty in exhausting the waste water vapor in that a means must be found to separate it from un-combusted fuel. This is unlike the case with PEM FCs, where the waste water leaves with the exhaust air. Our main solution to exhausting the water is the use of a membrane and perhaps a knockout drum to extract it from un-combusted fuel gases.

Our solution to the problem of carbon leaving the SOFC as CO is to react this CO with waste H2O to convert it to CO2 and additional H2. This is done in a water gas shift reactor, the WGS above. We then extract the CO2 and remaining, unused water through a CO2- specific membrane and we recycle the H2 and unconverted CO back to the SOFC using a low temperature recycle blower. The design above was modified from one in a paper by PNNL; that paper had neither a WGS reactor nor a membrane. As a result it got much worse fuel conversion, and required a high temperature recycle blower.

Heat must be removed from the SOFC output to cool it to a temperature suitable for the WGS reactor. In the design shown, the heat is used to heat the fuel before feeding it to the SOFC – this is done in the Rectifying HX. More heat must be removed before the gas can go to the CO2 extractor membrane; this heat is used to boil water for the steam reforming reaction. Additional heat inputs and exhausts will be needed for startup and load tracking. A solution to temporary heat imbalances is to adjust the voltage at the SOFC. The lower the voltage the more heat will be available to radiate to the steam reformer. At steady state operation, a heat balance suggests we will be able to provide sufficient heat to the steam reformer if we produce electricity at between 0.9 and 1.0 Volts per cell. The WGS reactor allows us to convert virtually all the fuel to water and CO2, with hardly any CO output. This was not possible for any design in the PNNL study cited above.

The drawing above shows water recycle. This is not a necessary part of the cycle. What is necessary is some degree of cooling of the WGS output. Boiling recycle water is shown because it can be a logistic benefit in certain situations, e.g. where you can not remove the necessary CO2 without removing too much of the water in the membrane module, and in mobile military situations, where it’s a benefit to reduce the amount of material that must be carried. If water or fuel must be boiled, it is worthwhile to do so by cooling the output from the WGS reactor. Using this heat saves energy and helps protect the high-selectivity membranes. Cooling also extends the life of the recycle blower and allows the lower-temperature recycle blowers. Ideally the temperature is not lowered so much that water begins to condense. Condensed water tends to disturb gas flow through a membrane module. The gas temperatures necessary to keep water from condensing in the module is about 180°C given typical, expected operating pressures of about 10 atm. The alternative is the use of a water knockout and a pressure reducer to prevent water condensation in membranes operated at lower temperatures, about 50°C.

Extracting the water in a knockout drum separate from the CO2 extraction has the secondary advantage of making it easier to adjust the water content in the fuel-gas stream. The temperature of condensation can then be used to control the water content; alternately, a separate membrane can extract water ahead of the CO2, with water content controlled by adjusting the pressure of the liquid water in the exit stream.

Some description of the membrane is worthwhile at this point since a key aspect of this patent – perhaps the key aspect — is the use of a CO2-extraction membrane. It is this addition to the fuel cycle that allows us to use the WGS reactor effectively to reduce coking and increase efficiency. The first reasonably effective CO2 extraction membranes appeared only about 5 years ago. These are made of silicone polymers like dimethylsiloxane, e.g. the Polaris membrane from MTR Inc. We can hope that better membranes will be developed in the following years, but the Polaris membrane is a reasonably acceptable option and available today, its only major shortcoming being its low operating temperature, about 50°C. Current Polaris membranes show H2-CO2 selectivity about 30 and a CO2 permeance about 1000 Barrers; these permeances suggest that high operating pressures would be desirable, and the preferred operation pressure could be 300 psi (20 atm) or higher. To operate the membrane with a humid gas stream at high pressure and 50°C will require the removal of most of the water upstream of the membrane module. For this, I’ve included a water knockout, or steam trap, shown in Figure 1. I also include a pressure reduction valve before the membrane (shown as an X in Figure 1). The pressure reduction helps prevent water condensation in the membrane modules. Better membranes may be able to operate at higher temperatures where this type of water knockout is not needed.

It seems likely that, no matter what improvements in membrane technology, the membrane will have to operate at pressures above about 6 atm, and likely above about 10 atm (upstream pressure) exhausting CO2 and water vapor to atmosphere. These high pressures are needed because the CO2 partial pressure in the fuel gas leaving the membrane module will have to be significantly higher than the CO2 exhaust pressure. Assuming a CO2 exhaust pressure of 0.7 atm or above and a desired 15% CO2 mol fraction in the fuel gas recycle, we can expect to need a minimum operating pressure of 4.7 atm at the membrane. Higher pressures, like 10 or 20 atm could be even more attractive.

In order to reform a carbon-based fuel, I expect the fuel cell to have to operate at 800°C or higher (Chick, 2011). Most fuels require high temperatures like this for reforming –methanol being a notable exception requiring only modest temperatures. If methanol is the fuel we will still want a rectifying heat exchanger, but it will be possible to put it after the Water-Gas Shift reactor, and it may be desirable for the reformer of this fuel to follow the fuel cell. When reforming sulfur-containing fuels, it is likely that a sulfur removal reactor will be needed. Several designs are available for this; I provide references to two below.

The overall system design I suggest should produce significantly more power per gm of carbon-based feed than the PNNL system (Chick, 2011). The combination of a rectifying heat exchange, a water gas reactor and CO2 extraction membrane recovers chemical energy that would otherwise be lost with the CO and H2 bleed steam. Further, the cooling stage allows the use of a lower temperature recycle pump with a fairly low compression ratio, likely 2 or less. The net result is to lower the pump cost and power drain. The fuel stream, shown in orange, is reheated without the use of a combustion pre-heater, another big advantage. While PNNL (Chick, 2011) has suggested an alternative route to recover most of the chemical energy through the use of a turbine power generator following the fuel cell, this design should have several advantages including greater reliability, and less noise.


1.   A power-producing, fuel cell system including a solid oxide fuel cell (SOFC) where a fuel-containing output stream from the fuel cell goes to a regenerative heat exchanger followed by a water gas shift reactor followed by a membrane means to extract waste gases including carbon dioxide (CO2) formed in said reactor. Said reactor operating a temperatures between 200 and 450°C and the extracted carbon dioxide leaving at near ambient pressure; the non-extracted gases being recycled to the fuel cell.

Main References:

The most relevant reference here is “Solid Oxide Fuel Cell and Power System Development at PNNL” by Larry Chick, Pacific Northwest National Laboratory March 29, 2011: Also see US patent  8394544. it’s from the same authors and somewhat similar, though not as good and only for methane, a high-hydrogen fuel.

Robert E. Buxbaum, REB Research, May 11, 2015.

How do technology companies sell stuff?

As the owner of a technology company, REB Research, hydrogen generators and hydrogen purifiers, I spend a fair amount of time trying to sell my stuff, and wondering how other companies connect to potential customers and sell to them. Sales is perhaps the most important area of business success, the one that makes or breaks most businesses — but it was sadly ignored in my extensive college education. Business books are hardly better: they ignore the salesmen (and women); you’re left to imagine sales and profit came of themselves by the insight of the great leader. The great, successful internet companies are applauded for giving away services, and the failed interned companies are barely mentioned. And hardly any book mentions smaller manufacturing businesses, like mine.

So here are some sales thoughts: things I tried, things that worked, and didn’t. I started my company, REB Research, about 20 years ago as a professor at Michigan State University. I figured I knew more about hydrogen purifiers than most of my colleagues, and imagined this knowledge would bring me money (big mistake: I needed customers and profitable sales). My strategy was to publish papers on hydrogen and get some patents as a way to build credibility (worked reasonably well: I write well, do research well, and I’m reasonably inventive). Patents might have been a better strategy if I had not then allowed my patents to be re-written by lawyers. I built the company. while still a professor (a good idea, I think).

When I realized I needed sales, I decided to use trade fairs, conferences, and ads as the big companies did. Most of my budget went for ads in The Thomas Register of American Manufacturing, a fantastically large compendium of who did or sold what (it worked OK, but was since rendered obsolete by the internet). I bought $1500 worth of ads, and got 2 small lines plus a 1/8 page. That’s where I got my sales until the internet cam along. In retrospect, I suspect I should have bought more ads.

William Hamilton cartoon from the new-yorker. I sure wish I could make deals.

William Hamilton cartoon from the new-yorker.

My other big expense was trade fairs. Many big companies sold at trade fairs, events that are widely attended in my field. Sorry to say, I never found customers at these fairs, even when the fairs were dedicated to hydrogen, everyone who’d come by was was selling, and no one was buying, as best I could tell.Somehow, my bigger competitors (also at the fairs) seemed to get interest but I’m not sure if they got sales there. They seem to find sales somewhere, though. Is it me? Am I at the wrong fairs, or are fairs just a scam where no one wins but the organizers? I don’t know. Last month, I spent $2000 for a booth in Ann Arbor, MI, including $350 for inclusion into the promoter’s book and $400 for hand-out literature. As with previous events, few people came by and none showed anything like interest, I got no e-mail addresses and no sales. Some hungry students wandered the stalls for food and freebees, but there was not one person with money in his/her pocket and a relevant project to spend it on. I doubt anyone read the literature they took.

To date, virtually all of my sales have come from the internet. I got on the internet early, and that has helped my placement in Google. I’ve never bought a google ad, but this may change. Instead I was lucky. About 20 years ago, 1994?, I attended a conference at Tufts on membrane reactors, and stayed at a bed-and-breakfast. After the conference let out, the owner of the BnB suggested I visit something that was new at Harvard; a cyber cafe, the second one in the US. They had Macintosh computers and internet explorer a year before the company went public. I was hooked, went home, learned html, and wrote a web-site. I bought my domain name shortly thereafter.

The problem, I don’t know the next big thing. Twitter? Facebook? LinkedIn? I’m on 2 of these 3, and have gotten so sales from social media. I started a blog (you’re reading it), but I still wonder, why are the bigger companies selling more? The main difference I see is they attend a lot more product fairs than I do, have slicker web-sties (not very good ones, I think), and they do print advertising. Perhaps they match their fairs to their products better, or have a broader range of products. People need to see my products somewhere, but where? My latest idea: this week I bought Send me advice, or wish me luck.

Robert E. Buxbaum, flailing entrepreneur, September 10, 2014. Here’s a feedback form, the first time I’m adding one. 

American education how do we succeed?

As the product of a top American college, Princeton University, I see that my education lacks in languages and history compared to Europeans. I can claim to know a little Latin and a little Greek, like they do, but I’m referring to Manuel Ramos and Stanos Platsis.

Americans hate math.

Americans hate math.

It was recently reported that one fourth of college-educated Americans did not know that the earth spun on an axis, a degree of science ignorance that would be inconceivable in any other country. Strange to say, despite these lacks, the US does quite well commercially, militarily, and scientifically. US productivity is the world’s highest. Our GNP and GNP per capita too is higher than virtually any other country (we got the grossest national product). How do we do it with so little education?

One part of US success is clearly imported talent, Immigration. We import Nobel chemists, Russian dancers, and German rocket scientists but we don’t import that many. They help our per-capita GNP, but the majority of our immigrants are more in the wretched refuse category. Even these appear to do better here than the colleagues they left behind. Otto von Bismark once joked that, “God protects children, drunks, and the United States of America.” But I’d like to suggest that our success is based on advantages our outlook our education provides for our more creative citizens.

Most of our successful businesses are not started by the A students, but by the C student who is able to use the little he (or she) knows. Consider the simple question of whether the earth goes round the sun. It’s an important fact, but only relevant if you can use it, as Sherlock Holmes points out. I suspect that few Europeans could use the knowledge that the earth spins (try to think of some applications; at the end of this essay I’ll provide some).

Benjamin Jowett. His students included the heads of 6 colleges and the head of Eaton

Benjamin Jowett, Master of Balliol College, Oxford.

A classic poem about European education describes Benjamin Jowett, shown at right. It goes: “The first come I, my name is Jowett. There is no knowledge, but that I know it. I am master of this college. What I don’t know isn’t knowledge.” Benjamin Jowett was Master of Balliol College, Oxford. By the time he died in 1893, his ex-student pallbearers included the heads of 6 colleges, and the head of Eaton. Most English heads of state and industry were his students directly or second-hand. All learned a passing knowledge of Greek, Latin, Plato, law, science, theology, classics, math, rhetoric, logic, and grammar. Only people so educated were deemed suited to run banks or manage backward nations like India or Rhodesia. It worked for a while but showed its limitations, e.g. in the Boer Wars.

In France and continental Europe the education system is similar to England’s under Jowett. There is a fixed set of knowledge and a fixed rate to learn it. Government and industry jobs go largely to those who’ve demonstrated their ability to give the fixed, correct answers to tests on this knowledge. In schools across France, the same page is turned virtually simultaneously in the every school– no student is left behind, but none jump ahead either. As new knowledge is integrated, the approved text books are updated and the correct answers are adjusted. Until then, the answers in the book are God’s truth, and those who master it can comfort themselves to have mastered the truth. The only people hurt are the very few dummies who see a new truth a year before the test acknowledges it. “College is a place where pebbles are polished but diamonds are dimmed.” The European system appears to benefit the many, providing useful skills (and useless tidbits) but it is oppressive to many others with forward-thinking, imaginative minds. The system appears to work best in areas that barely change year-to-year like French grammar, geometry, law, and the map of Europe. It does not work so well in music, computers, or the art of war. For these students, schooling is “another brick in the wall. For these students, the schools should teach more of how to get along without a teacher.

The American approach to education leans towards independence of thought, for good or bad. American graduates can live without the teacher, but leave school knowing no language but English, hardly and maths or science, hardly any grammar, and we can hardly find another country on a map. Teachers will take incorrect answers as correct as a way to build self-esteem, so students leave with the view that there is no such thing as truth. This model works well in music, engineering, and science where change is fast, creativity is king, and nature itself is a teacher. American graduate-schools are preeminent in these areas. In reading, history and math our graduates might well be described as galumphing ignorants.

Every now and again the US tries to correct this, by the way, and join the rest of the world. The “no child left behind” movement was a Republican-led effort to teach reading and math on the French model. It never caught on. Drugs are another approach to making American students less obstreperous, but they too work only temporarily. Despite these best efforts, American graduates leave school ignorant, but not stupid; respectful of those who can do things, and suspicious of those with lengthy degrees. We survive as managers of the most complex operations with our bumptious optimism and distain for hierarchy. As viewed from abroad, our method is to greet colleagues in a loud, cheerful voice, appoint a subordinate to “get things done,” and then get in the way until lunchtime.

In any moment of decision, the best thing you can do is the right thing, the next bet thing is the wrong thing, and the worst thing you can do is nothing. An American attitude that sometimes blows up, but works surprisingly well at times.

Often the inability to act is worse than acting wrong.

The American-educated boss will do some damage by his ignorance but it is no more than  comes from group-think: non-truths passed as truths. America stopped burning witches far sooner than Europe, and never burned Jews. America dropped nobles quicker, and transitioned to electric lights and motor cars quicker, perhaps because we put less weight on what nobles and universities did.

European scholars accepted that nobility gave one a better handle on leadership, and this held them back. Since religion was part of education, they accepted that state should have an established religion: Anglican, in England, Catholicism in France; scientific atheism now. They learned and accepted that divorce was unnecessary and that homosexuality should be punished by prison or worse. As late as the early 60s, Turing, the brilliant mathematician and computer scientist, was chemically castrated as a way to cure his homosexuality. In America our “Yankee ingenuity,” as we call it, had a tendency to blow up, too (prohibition, McCarthyism, and disco), but the problems resolved relatively soon. “Ready, fire, aim” is a European description of the American method. It’s not great, but works after a fashion.

The best option, I think, is to work together with those from “across the pond.” It worked well for us in WWI, WWII, and the American Revolution, where we benefitted from the training of Baron Von Steuben, for example. Heading into the world cup of football (fifa soccer) this week, we’re expected to lose badly due to our lack of stars, and general inability to pass, dribble, or strategize. Still, we’ve got enthusiasm, and we’ve got a German coach. The world’s bookies give us 0.05% odds, but our chances are 10 times that, I’d say: 5%. God protects our galumphing side of corn-fed ignorants when, as in the Revolution, it’s attached to German coaching.

Some practical aspects of the earth spinning: geosynchronous satellites (they only work because the earth spins), weather prediction (the spin of hurricanes is because the earth spins), cyclone lifting. It amazes me that people ever thought everything went around the earth, by the way; Mercury and Venus never appear overhead. If authorities could have been so wrong about this for so long, what might they be wrong about today?

Dr. Robert Buxbaum, June 10, 2014 I’ve also written about ADHD on Lincoln’s Gettysburg Address, on Theodore Roosevelt, and how he survived a gun shot.

Is ADHD a real disorder

When I was in school, ADHD hadn’t been invented. There were kids who didn’t pay attention for a good part of the day, or who couldn’t sit in their seats, but the first activity was called day-dreaming and the second “shpilkas” or “ants in your pants.” These problems were recognized but were considered “normal.” Though we were sometimes disorderly, the cause wasn’t labeled a disorder. It’s now an epidemic.

There were always plenty of kids, me included, who were day-dreamers. Mostly these were boys who would get bored after a while and would start to look around the room, or doodle, or gaze into space thinking of this or that. Perhaps I’d do some writing or math in the margin of a notebook while listening with one ear; perhaps I’d work on my handwriting, or I’d read something in another textbook. This was not called a disorder or even an attention deficit (AD), but rather day-dreaming, wool-gathering, napping, or just not paying attention. Sometimes teachers got annoyed, other times not. They went on teaching, but sometimes tossed chalk or erasers at us to get us to wake up. Kids like me took enough notes to do OK on tests and homework, though I was never at the top of the class in elementary or middle school. The report cards tended to say things like “he could do better if he really concentrated.”  It’s something that could apply to everyone.

Then there were the boys who would now be labeled HD, or “hyperactive disordered.” These were always boys: those who didn’t sit well in their chairs, or fidgeted, or were motor mouths and got up and walked about, or got into fights, or went to the bathroom; these were the class clowns, and the trouble makers — not me except for the fidgeting. Girls would fidget or talk too, and they’d pass notes to each other, but they didn’t get into fights, and they weren’t as disruptive. They tended to have great handwriting, and took lots of notes in class: every single word from the board, plus quite a bit more.

There are different measures of education, if you measure a fish's intelligence by the ability to climb a tree it will spend its life thinking it's stupid.

There are different measures of education, if you measure a fish’s skill level by the ability to climb a tree you’ll conclude the fish is ADD or worse.

Elementary and middle schools had activities to work out the excess energy that caused hyper-activity. We had dancing, shop, fire drills, art, some music, and sports. None of these helped all that much, but they did some good. I think the fire drills helped the most because we all went outside even in the winter, and eventually we calmed down without drugs. Sometimes a kid didn’t calm down, got worse, and did real damage; these kids were not called hyperactive disordered, but “bad kids” or “juvenile delinquents.” Nowadays, schools have far less art and music, and no shop or dancing. There are a lot more hyperactive kids, and the claim nowadays is that these hyperactive kids, violent or not, are disordered, ADHD, and should be given drugs. With drugs, the daydreamers take better notes, the nappers wake up, and the hyperactive kids calm down. Today about 30% of high-school seniors are given either a version of amphetamine, e.g. Adderall, or of Methylphenidate (Ritalin, etc.) The violent ones, the juvenile delinquents, are given stronger versions of the same drugs, e.g. methamphetamine, the drug at the heart of “breaking bad.”

Giving drugs to the kids seems to help the teacher a lot more than it helps the kids. According to a famous joke, giving the Ritalin to the teacher would be the best solution. When the kids are given drugs the disorderly boys (it’s usually given to boys) begin to act more like “goodie goodies”. They sit better and pay attention more; they take better notes and don’t interrupt, but I’m not sure they are learning more, or that the class is, or that they are socializing any better than before. The “goodie-goodies” in elementary school (mostly girls) did great in the early grades, but their good habits seemed to hold them back later. They worked too hard to please and tended to not notice, or pretended to not notice, when the teacher said nonsense. When it came time for independent or creative endeavors, their diligent acceptance of authority stood in the way of excellence.Venn diagram of ADHD

The hyperactive and daydreamers were more used to thinking for themselves, a prerequisite of leadership. The AD ones had gotten used to half-ignoring the teacher, and the HD ones were more openly opinionated and oppositional: obstreperous, in a word. Those bright enough to get by got more out of their education, perhaps because it was more theirs. To the extent that education was supposed to make you a leader and a thinker, the goodie-goodie behavior was a distraction and a disorder. This might be expected if education is supposed to be the lighting of a fire, not the filling of a pit. If everyone thinks the same, it’s a sign that few are thinking.

Map  of ADHD variation with location for US kids ages 6-18, Scrips Research.

Map of ADHD variation with location for US kids ages 6-18, Scrips Research. Boys are 2-3 times more often diagnosed as ADHD; diagnosis and medication increase with grade, peaking currently in early college.

This is not to say that there is no such disorder as ADHD, or no benefit from the drugs. My sense, though, is that the label is given too widely, and that the drugs are given too freely. Today drugs are pushed on virtually any kid who’s distracted, napping or hyperactive — to all the members of the big circles in the Venn diagram above, plus to athletes and others who feign ADD to get these, otherwise illegal, performance enhancing drugs. Currently, about 10% of US kids between 6 and 18 are diagnosed ADHD and given drugs, see figure. The numbers higher for boys than girls, higher in the US than abroad, and higher as the kids progress through school. It’s estimated that about 25% of US, 12th grade boys are given amphetamine or Ritalin and its homologs. My sense is that only a small fraction of these deserve drugs, only those with severe social problems, the violent or narcoleptic: those in the smaller circles of the Venn diagram. The test should not be that the kid’s behavior improves on them. Everyone’s attention improves when taking speed. ADHD appears more as an epidemic of overworked, undertrained, underfunded teachers, and a lack of outlets, not of disordered kids, or of real learning, and real learning is never pretty or easy (on all involved).

Robert Buxbaum, April 18, 2014. In general, I think people would be happier if they’d do more artmusicdance and shop, and if they’d embrace their inner weirdo. It would also help if doctors and teachers would use words rather than initials to describe people. It’s far better to be told you’re hyperactive, or that you’re not paying attention, then to be called ADD, HD, or ADHD. There’s far more room for gradation and improvement. I’m not an expert, just an observant observer.

Be Art

You are your own sculpture; Be art.

Here I am wearing a sculpture I made, called Gilroy. The Idea is based on the drawings of Kilroy made during WW2, but to make things spookier the eyes follow you as shown in this video. I suspect that the original drawings were made to discredit the Nazi’s by undermining the sense that they brought order and were the inevitable power in the area.

Feb. 2013 – March, 2015

Physics of no fear, no fall ladders

I recently achieved a somewhat mastery over my fear of heights while working on the flat roof of our lab building / factory. I decided to fix the flat roof of our hydrogen engineering company, REB Research (with help from employees), and that required me to climb some 20 feet to the roof to do some work myself and inspect the work of others. I was pretty sure we could tar the roof cheaper and better than the companies we’d used in the past, and decided that the roof  should be painted white over the tar or that silvered tar should be used — see why. So far the roof is holding up pretty well (looks good, no leaks) and my summer air-conditioning bills were lowered as well.

Perhaps the main part of overcoming my fear of heights was practice, but another part was understanding the physics of what it takes to climb a tall ladder safely. Once I was sure I knew what to do, I was far less afraid. As Emil Faber famously said, “Knowledge is good.”

me on tall ladder

Me on tall ladder and forces. It helps to use the step above the roof, and to have a ladder that extends 3-4′ feet past roof level

One big thing I learned (and this isn’t physics), was to not look down, especially when you are going down the ladder. It’s best to look at the ladder and make sure your hands and feet are going where they should. The next trick I learned was to use a tall ladder — one that I could angle at 20° and extends 4 feet above the roof, see figure. Those 4 feet gave me something to hold on to, and something to look at while going on and off the ladder. I found I preferred to go to or from the roof from a rung that was either at the level of the roof, or a half-step above (see figure). By contrast, I found it quite scary to step on a ladder rung that was significantly below roof level even when I had an extended ladder. I bought my ladder from Acme Ladder of Capital St. in Oak Park; a fiberglass ladder, light weight and rot-proof.

I preferred to set the ladder level (with the help of a shim if needed) at an angle about 20° to the wall, see figure. At this angle, I felt certain the ladder would not tip over from the wind or my motion, and that it would not slip at the bottom, see calculations below.

if the force of the wall acts at right angles to the ladder (mostly horizontally), the wall force will depend only on the lever angle and the center of mass for me and the ladder. It will be somewhat less than the total weight of me and the ladder times sin 20°. Since sin 20° is 0.342, I’ll say the wall force will be less than 30% of the total weight, about 65lb. The wall force provides some lift to the ladder, 34.2% of the wall force, about 22 lb, or 10% of the total weight. Mostly, the wall provides horizontal force, 65 lb x cos 20°, or about 60 lbs. This is what keeps the ladder from tipping backward if I make a sudden motion, and this is the force that must be restrained by friction from the ladder feet. At a steeper angle the anti-tip force would be less, but the slip tendency would be less too.

The rest of the total weight of me and the ladder, the 90% of the weight that is not supported by the roof, rests on the ground. This is called the “normal force,” the force in the vertical direction from the ground. The friction force, what keeps the ladder from slipping out while I’m on it, is this “normal force” times the ‘friction factor’ of the ground. The bottom of my ladder has rubber pads, suggesting a likely friction factor of .8, and perhaps more. As the normal force will be about 90% of the total weight, the slip-restraining force is calculated to be at least 72% of this weight, more than double the 28% of weight that the wall pushes with. The difference, some 44% of the weight (100 lbs or so) is what keeps the ladder from slipping, even when I get on and off the ladder. I find that I don’t need a person on the ground for physics reasons, but sometimes found it helped to steady my nerves, especially in a strong wind.

Things are not so rosy if you use a near vertical ladder, with <10° to the wall, or a widely inclined one, >40°. The vertical ladder can tip over, and the widely inclined ladder can slip at the bottom, especially if you climb past the top of the roof or if your ladder is on a slippery surface without rubber feet.

Robert E. Buxbaum Nov 20, 2013. For a visit to our lab, see here. For some thoughts on wind force, and comments on Engineering aesthetics. I owe to Th. Roosevelt the manly idea that overcoming fear is a worthy achievement. Here he is riding a moose. Here are some advantages of our hydrogen generators for gas chromatography.

An Aesthetic of Mechanical Strength

Back when I taught materials science to chemical engineers, I used the following poem to teach my aesthetic for the strength target for product design:

The secret to design, as the parson explained, is that the weakest part must withstand the strain. And if that part is to withstand the test, then it must be made as strong as all the rest. (by R.E. Buxbaum, based on “The Wonderful, One-hoss Shay, by Oliver Wendell Holmes, 1858).

My thought was, if my students had no idea what good mechanical design looked like, they’d never  be able to it well. I wanted them to realize that there is always a weakest part of any device or process for every type of failure. Good design accepts this and designs everything else around it. You make sure that the device will fail at a part of your choosing, when it fails, preferably one that you can repair easily and cheaply (a fuse, or a door hinge), and which doesn’t cause too much mayhem when it fails. Once this failure part is chosen and in place, I taught that the rest should be stronger, but there is no point in making any other part of that failure chain significantly stronger than the weakest link. Thus for example, once you’ve decided to use a fuse of a certain amperage, there is no point in making the rest of the wiring take more than 2-3 times the amperage of the fuse.

This is an aesthetic argument, of course, but it’s important for a person to know what good work looks like (to me, and perhaps to the student) — beyond just by compliments from the boss or grades from me. Some day, I’ll be gone, and the boss won’t be looking. There are other design issues too: If you don’t know what the failure point is, make a prototype and test it to failure, and if you don’t like what you see, remodel accordingly. If you like the point of failure but decide you really want to make the device stronger or more robust, be aware that this may involve strengthening that part only, or strengthening the entire chain of parts so they are as failure resistant as this part (the former is cheaper).

I also wanted to teach that there are many failure chains to look out for: many ways that things can wrong beyond breaking. Check for failure by fire, melting, explosion, smell, shock, rust, and even color change. Color change should not be ignored, BTW; there are many products that people won’t use as soon as they look bad (cars, for example). Make sure that each failure chain has it’s own known, chosen weak link. In a car, the paint on a car should fade, chip, or peel some (small) time before the metal underneath starts rusting or sagging (at least that’s my aesthetic). And in the DuPont gun-powder mill below, one wall should be weaker so that the walls should blow outward the right way (away from traffic).Be aware that human error is the most common failure mode: design to make things acceptably idiot-proof.

Dupont powder mills had a thinner wall and a stronger wall so that, if there were an explosion it would blow out towards the river. This mill has a second wall to protect workers. The thinner wall should be barely strong enough to stand up to wind and rain; the stronger walls should stand up to explosions that blow out the other wall.

Dupont powder mills had a thinner wall and a stronger wall so that, if there were an explosion, it would blow out ‘safely.’ This mill has a second wall to protect workers. The thinner wall must be strong enough to stand up to wind and rain; the stronger walls should stand up to all likely explosions.

Related to my aesthetic of mechanical strength, I tried to teach an aesthetic of cost, weight, appearance, and green: Choose materials that are cheaper, rather than more expensive; use less weight rather than more if both ways worked equally well. Use materials that look better if you’ve got the choice, and use recyclable materials. These all derive from the well-known axiom, omit needless stuff. Or, as William of Occam put it, “Entia non sunt multiplicanda sine necessitate.” As an aside, I’ve found that, when engineers use Latin, we look smart: “lingua bona lingua motua est.” (a good language is a dead language) — it’s the same with quoting 19th century poets, BTW: dead 19th century poets are far better than undead ones, but I digress.

Use of recyclable materials gets you out of lots of problems relative to materials that must be disposed of. E.g. if you use aluminum insulation (recyclable) instead of ceramic fiber, you will have an easier time getting rid of the scrap. As a result, you are not as likely to expose your workers (or you) to mesothelioma, or similar disease. You should not have to pay someone to haul away excess or damaged product; a scraper will oblige, and he may even pay you for it if you have enough. Recycling helps cash flow with decommissioning too, when money is tight. It’s better to find your $1 worth of scrap is now worth $2 instead of discovering that your $1 worth of garbage now costs $2 to haul away. By the way, most heat loss is from black body radiation, so aluminum foil may actually work better than ceramics of the same thermal conductivity.

Buildings can be recycled too. Buy them and sell them as needed. Shipping containers make for great lab buildings because they are cheap, strong, and movable. You can sell them off-site when you’re done. We have a shipping container lab building, and a shipping container storage building — both worth more now than when I bought them. They are also rather attractive with our advertising on them — attractive according to my design aesthetic. Here’s an insight into why chemical engineers earn more than chemists; and insight into the difference between mechanical engineering and civil engineering. Here’s an architecture aesthetic. Here’s one about the scientific method.

Robert E. Buxbaum, October 31, 2013

How to make fine lemonade

As part of discussing a comment by H.L. Mencken, that a philosopher was a man in a dark room looking for a black cat that wasn’t there, I alluded to the idea that a good person should make something or do something, perhaps make lemonade, but I gave no recipe. Here is the recipe for lemonade something you can do with your life that benefits everyone around:

The key is to use lots of water, and not too much lemon. Start a fresh lemon and two 16 oz glasses. Cut the lemon in half and squeeze half into each glass, squeezing out all of the juice by hand (you can use a squeezer). Ideally, you should pass the juice through a screen for the pits, but if you don’t have one it’s OK — pits sink to the bottom. Add 8 oz of water and 2 tbs of sugar to each (1/8 cup). Stir well until the sugar dissolves, add the lemon rind (I like to cut this into 3rds); stir again and add a handful of ice. This should get you to 3/4″ of the top, but if not add more water. Enjoy.

For a more-adult version, use less water and sugar, but add a shot of Cognac and a shot of Cointreau. It’s called a side-car, one of the greatest of all drinks.

Robert E. Buxbaum *82

yet another quantum joke

Why do you get more energy from a steak than from the same amount of hamburger?


Hamburger is steak in the ground state.


Is funny because….. it’s a pun on the word ground. Hamburger is ground-up meat, of course, but the reference to a ground state also relates to a basic discovery of quantum mechanics (QM): that all things exist in quantized energy states. The lowest of these is called the ground state, and you get less energy out of a process if you start with things at this ground state. Lasers, as an example, get their energy by electrons being made to drop to their ground state at the same time; you can’t get any energy from a laser if the electrons start in the ground state.

The total energy of a thing can be thought of as having a kinetic and a potential energy part. The potential energy is usually higher the more an item moves from its ideal (lowest potential point). The kinetic energies of though tends to get lower when more space is available because, from Heisenberg uncertainty, ∆l•∆v=h. That is, the more space there is, the less uncertainty of speed, and thus the less kinetic energy other things being equal. The ground energy state is the lowest sum of potential and kinetic energy, and thus all things occupy a cloud of some size, even at the ground state. Without this size, the world would cease to exist. Atoms would radiate energy, and shrink until they vanished.

In grad school, I got into understanding thermodynamics, transport phenomena, and quantum mechanics, particularly involving hydrogen. This lead to my hydrogen production and purification inventions, what my company sells.

Click here for a quantum cartoon on waves and particles, an old Heisenberg joke, or a joke about how many quantum mechanicians it takes to change a lightbulb.

R. E. Buxbaum, July 16, 2013. I once claimed that the unseen process that maintains existence could be called God; this did not go well with the religious.