Monthly Archives: July 2017

Global warming’s 19 year pause

Global temperatures measured from the antarctic ice showing stable, cyclic chaos and self-similarity.

Global temperatures measured from the antarctic ice shows stable chaos and self-similarity.

The global climate is, as best I can tell, chaotic with 100,000 year ice-age cycles punctuated by smaller cycles of 1000 years, 100 years, etc. On the ice-age time scale shown at left, the temperature rise of the last century looks insignificant and very welcome; warm seems better than cold in my eyes. But the press and academic community has focused on the evils of warmth — global warming. They point out that temperatures have risen 1 1/2 °C since the little ice age of the early 1600s, and that 1/2 °C of this has occurred since 1900. Al Gore won a Nobel prize for his assertion that the rate of rise had accelerated to 4°C per century — a “hockey-stick change” caused by industrial CO2. This change was expected to bring disaster by 2015: The arctic was supposed to be ice-free, and Manhattan was expected to sink. I’ve posted a “Good Morning America” clip from 2008 highlighting this “inconvenient truth”.

Our 19 1/2 year global warming pause; plot from Andrew Watts with Al Gore's prediction shown in red. During the time shown, the atmospheric CO2 content has gone up by about 25%, but the prediction has not come to pass.

Our 19 1/2 year global warming pause; plot from Andrew Watts with Al Gore’s prediction shown in red. So far, the prediction has not come to pass.

As it happens, not only hasn’t global warming accelerated, it seems to have paused. There have been no significant temperature changes since late 1997, as shown.  The main explanations are clouds and solar variation: variations that the Obama administration claims will end any day now. The problem, as I see it, is that climate is fundamentally chaotic, and thus unpredictable except on the very long, ice-age, timescale. It will thus always make fools of those who predict.

This is not to say that pollution is good, or that CO2 is, but it suggests our models and remedies are flawed. The CO2 content of the air has increased 25% over the past 19 years. It now mostly comes from China and India, countries that enthusiastically endorse having us reduce our output. My thinking is that lowering US production will, in no way, protect us from the dire predictions below.

Despite pressure from China and India, the US pulled out of the Paris climate accord last month. It now seems several other countries will pull out as well.

Robert Buxbaum, July 27, 2017. I’ve also written about how the global warming of the mid 1800s lead us to have the president’s Resolute desk.

Detroit 1967 to 2017: unemployment comes down, murder rate doesn’t.

Almost 50 years ago today, July 23, 1967 white policemen raided an unlicensed, “blind pig” bar in a black neighborhood, the 12th street of Detroit, and the city responded with four days of rioting, 43 killings (33 black, 10 white), 2509 stores looted, and over 1000 fires. In 2017, at last the city is beginning to show signs of recovery. By 2015 the city’s unemployment had gone down from about 20% to 12%, and  in the first six months 2017, the firs six months of the Trump presidency, 2017 it’s gone down again to 7 1/2%. It’s not that 7 1/2% unemployment is good, but it’s better. Per-hour salaries are hardly up, but I take that as better than having a high average salary at very low employment. As a point of reference, the unemployment rate in Detroit in 1967, before the riots was 3.4%. Within weeks, 150,000 jobs were lost, and anyone who could leave the city, did.

Detroit Unemployment rates are way down, but the city still looks like a mess.

Detroit Unemployment rates are way down, but the city still looks like a mess.

Another issue for Detroit is its uncommonly high murder rate. In the mid-80s, Detroit had the highest murder rate in the US, about 55 murders per 100,000 population per year (0.055%/year). As of February 1, 2017, the murder rate was virtually unchanged: 50 per 100,000 or 0.05%/year, but two cities have higher rates yet. At present rates, you have a 3.5% of dying by homicide if you live in Detroit for 70 years — even higher if you’re male. The rate in the rest of the US is about 1/10th this, 0.005%/year, or 5 per 100,000, with a dramatic difference between rural and urban populations.

Murder rate in 50 cities with Detroit highlighted. From The Economist, February 2017.

Murder rate in 50 cities with Detroit highlighted, from The Economist.

One of the causes of the high murder rate in Detroit, and in the US generally, I suspect, is our stiff, minimum-penalties for crime. As sir Thomas Moose pointed out, when crime is punished severely, there is a tendency to murder. If you’re going to spend the next 20 years behind bars, you might as well try any means you can to escape. Another thought — the one favored by social liberals — is that it’s the presence of guns in the US encourages murder. It may, but it also seems to prevent crime by allowing the victim to defend himself or herself. And the effect on murder is not so clear, if you consider suicide as a form of murder. In countries like Canada with few guns, people kill themselves by hanging or by throwing themselves off high buildings. My hope is that Detroit’s murder rate will drop in 2017 to match its improved economic condition, but have no clear reason to think it will.

Robert Buxbaum, July 20, 2017. Here are some suggestions I’ve made over the years.

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.

Peace killed the Indian, ended Spain’s golden age

The why of history is always more speculative than the what. Yet, to write about only the what, is to do only half of the job, if that. The what is largely interchangeable: the names of kings and generals, the dates and locals of battles and treaties. It’s the why that adds interest, and provides whatever lessons one can take forward. With this as background, I’d like to speculate on the cause of: the destruction of the American Indian, and the end of the golden age of Spain. For both and some others, I suggest an unusual villain, peace: too much peace. It’s a speculative why, but bear with me.

Lets start with the American Indian. In the mid 1700s, Indians controlled the majority of the continent. They had an advanced society of six main nations, held together by mutual treaty. The Indians had few guns, but were not less intelligent than the Japanese or Chinese, suggesting that they could have learned to make them if they desired (or realized they needed to desire). The Japanese did so in short order. Indians addressed the Continental assemblies, and though they were not integrated, quite, they were not segregated either. But this first period of co-existence ended, as best i can tell, in the years of and following the French and Indian war. In the war, some Indians supported the French and some the British, and each side looked after their Indians. After peace was established, however, English leaders like Lord Jeffery Amherst set up to wipe out the Indians of both sides, “this execrable race,” with blankets infected with smallpox, and good old-fashioned cruelty. His activities are memorialized, on the cafeteria china used at Amherst Colleges till the 1960s.

Cup from the cafeteria of Amherst College shows Lord Jeff pursuing the Indians.

Cup from the cafeteria of Amherst College, used till the 1960s, shows Lord Jeffery Amherst pursuing a band of Indians. Purple and white are the Amherst colors. 

My thought of why he did it, and why he succeeded, is that the Indians had outlived their usefulness. The ones on the French side had been enemies, and might be again. The ones on his, English side were annoying and might turn in the next conflict. Besides, Lord Jeffery and his ilk had idle military power. Removing the Indians was something they could do. The army at peace could otherwise get destructive, or turn on him (I’m speculating here on motives).

This pattern appeared again in the Revolutionary war and in the War of 1812. During each war, Indians were befriended by both sides, and recruited. Indians fought important battles in each war, now mostly forgotten; the defense of Canada was largely by Indians. After each war, these Indians were largely betrayed. In the War of 1812, the Shawnee, Potawatomi, Ojibwa, and Creek mostly sided with the British, led by the fierce Shawnee general, Tecumseh. The Muscogee, Creek, Seminole, Choctaw, Cherokee, and Chickasaw, mostly sided with the US. Iroquois fought on both sides. In the years following the wars, these and these were sent west of the Mississippi. Those who had been allies with the US were paid for their land, those that sided with the British were not. A good price, but it was a forced sale none-the-less. I will speculate that they were exiled because they retained a government structure independent of the US, making them a threat. Also (I speculate) the military, Generals Harrison, Jackson, etc., had nothing better to do with an army that might have mutinied otherwise. By 1846, there was no serious future for the American Indian east of the Mississippi, and besides, there was an external enemy to fight — The Mexicans. My speculation: the Indians were destroyed by “the era of good feelings” that follows war.

In the case of Spain, I note that the Inquisition and Jewish expulsion followed suddenly after 300 years of science, art, literature, and coöperation. I also note that the Alhambra decrees (March 1492) followed almost immediately after the defeat the last major Moslem-held citadel, Granada in December, 1491, and the peace treaty of Granada (January 2, 1492). The Alhambra decrees of March 31, 1492 mandated that all Jews must convert or leave Spain, and gave free-reign to the Inquisition to punish heresy. At the time, the financier of the Spanish crown was a Jew, Don Isaac Abarbanel. And some years earlier another Jew, Shmuel HaNagged hand been vizier (2nd) to the king. My theory of the cause for the sudden switch is that it was not a sudden surge in religion, as some have suggested, but rather that the king and queen no longer needed an army or Jewish or Moslem allies, but they still had an army that might turn against them if not otherwise occupied.

In the interwar, peace years, Stalin removed 3 of the 5 top generals, 13 of 15 below them; 8 of 9 admirals, 50 of 57 army corps commanders, 154 out of 186 division commanders, 16 of 16 army commissars, and 25 of 28 army corps commissars.

In the interwar, peace years, Stalin removed 3 of the 5 top generals, 13 of 15 below them; 8 of 9 admirals, 50 of 57 army corps commanders, 154 out of 186 division commanders, 16 of 16 army commissars, and 25 of 28 army corps commissars. Peace is hell.

I’m reminded that peace is the background to intrigue in at least six of Shakespeare’s historical plays: Macbeth, Hamlet, Richard III, Lear, Julius Caesar, and Othello. Richard III explains his behavior as follows (Act I, Scene 1):  “Why, I, in this weak piping time of peace, have no delight to pass away the time, unless to spy my shadow in the sun and descant on mine own deformity.”

A few other examples: After WWI, most of Europe removed their bearded aristocracy, and Stalin used the peacetime to remove much of the communist leadership including many of his generals and former friends – this was especially so after signing a peace treaty with Germany. And, in the US after WWII, we entered a period of communist witch hunts — a mini Inquisition directed at the writers and artists who provided Allied propaganda during the war. Even a general good, like peace can leave casualties.

Robert Buxbaum, July 7, 2017. I like to speculate on the why of history, and like to imagine my speculations are partially true, at least.

Heraclitus and Parmenides time joke

From Existential Commics

From Existential Comics; Parmenides believed that nothing changed, nor could it.

For those who don’t remember, Heraclitus believed that change was the essence of life, while  Parmenides believed that nothing ever changes. It’s a debate that exists to this day in physics, and also in religion (there is nothing new under the sun, etc.). In science, the view that no real change is possible is founded in Schrödinger’s wave view of quantum mechanics.

Schrödinger's wave equation, time dependent.

Schrödinger’s wave equation, time dependent.

In Schrödinger’s wave description of reality, every object or particle is considered a wave of probability. What appears to us as motion is nothing more than the wave oscillating back and forth in its potential field. Nothing has a position or velocity, quite, only random interactions with other waves, and all of these are reversible. Because of the time reversibility of the equation, long-term, the system is conservative. The wave returns to where it was, and no entropy is created, long-term. Anything that happens will happen again, in reverse. See here for more on Schrödinger waves.

Thermodynamics is in stark contradiction to this quantum view. To thermodynamics, and to common observation, entropy goes ever upward, and nothing is reversible without outside intervention. Things break but don’t fix themselves. It’s this entropy increase that tells you that you are going forward in time. You know that time is going forward if you can, at will, drop an ice-cube into hot tea to produce lukewarm, diluted tea. If you can do the reverse, time is going backward. It’s a problem that besets Dr. Who, but few others.

One way that I’ve seen to get out of the general problem of quantum time is to assume the observed universe is a black hole or some other closed system, and take it as an issue of reference frame. As seen from the outside of a black hole (or a closed system without observation) time stops and nothing changes. Within a black hole or closed system, there is constant observation, and there is time and change. It’s not a great way out of the contradiction, but it’s the best I know of.

Predestination makes a certain physics and religious sense, it just doesn't match personal experience very well.

Predestination makes a certain physics and religious sense, it just doesn’t match personal experience very well.

The religion version of this problem is as follows: God, in most religions, has fore-knowledge. That is, He knows what will happen, and that presumes we have no free will. The problem with that is, without free-will, there can be no fair judgment, no right or wrong. There are a few ways out of this, and these lie behind many of the religious splits of the 1700s. A lot of the humor of Calvin and Hobbes comics comes because Calvin is a Calvinist, convinced of fatalistic predestination; Hobbes believes in free will. Most religions take a position somewhere in-between, but all have their problems.

Applying the black-hole model to God gives the following, alternative answer, one that isn’t very satisfying IMHO, but at least it matches physics. One might assume predestination for a God that is outside the universe — He sees only an unchanging system, while we, inside see time and change and free will. One of the problems with this is it posits a distant creator who cares little for us and sees none of the details. A more positive view of time appears in Dr. Who. For Dr. Who time is fluid, with some fixed points. Here’s my view of Dr. Who’s physics.  Unfortunately, Dr. Who is fiction: attractive, but without basis. Time, as it were, is an issue for the ages.

Robert Buxbaum, Philosophical musings, Friday afternoon, June 30, 2017.