Improvised filtration devices

I knew I had encountered a list of filtration efficiencies for a number of materials. The point was that in a contamination episode, you had access to any number of improvised filters that were better than nothing. I finally found a book of the handouts for my Physics 468-B class decades ago, and lo and behold!

Respiratory protection provided by common household and personal items against aerosols of 1 to 5 µ particle size

Item# of thicknessesResistance: mm H2O# of ObservationsEfficiency, Geometric mean99% confidence, lower99% confidence, upper
Handkerchief, man’s cotton16363294.292.6395.5
Toilet paper3133291.489.892.8
Handkerchief, man’s cotton8183288.985.591.6
Handkerchief, man’s cottoncrumpled3288.185.190.5
Bath towel, Turkish2113285.183.386.8
Bath towel, Turkish153073.970.778.8
Bed sheet, muslin122327268.874.9
Bath towel, Turkish1 (wet)33170.26872.3
Shirt, cotton1 (wet)>150 (a)1565.957.972.3
Shirt, cotton273065.560.869.6
Handkerchief, woman’s cotton4 (wet)84 (a)326357.358.7
Handkerchief, man’s cotton1 (wet)98 (a)3062.65767.5
Dress material, cotton1 (wet)180 (a)3156.349.662
Handkerchief, woman’s cotton4 (wet)23255.552.258.7
Slip, rayon16325046.253.6
Dress material, cotton153147.641.453.2
Shirt, cotton133234.62939.9
Handkerchief, man’s cotton123227.52232.5

(a) Resistance obtained when checked immediately after hand wringing. This resistance began to decrease after about one minute when the material started to dry.

I’m not sure of the original source. It may be an old version of an OSSHA handbook.

Ten Million Cases

A post on the Book of Feces Faces was lamenting that we’re up to ten million cases of Covid-19. Just for perspective, the CDC estimates that during the 2018-2019 season, the US had some 35.5 million cases of the flu. Of these, 16.5 million people went to a health care provider for their illness, 490,600 were hospitalized, and 34,200 died.

So worldwide, we have just over 10 million cases of Covid-10. Of these, nearly 503,000 have died. In the USA, we’ve had 2.6 million cases, and 128 thousand deaths. So there are a lot fewer cases, but it does seem to have a higher mortality rate.

I still wonder what the reaction would have been had the news presented daily counts of the numbers of cases and deaths from flu two years ago.

Is infinite economic growth a fantasy? Or is the fantasy the idea that we are quickly using up the Earth?

In his recent book, “ Stubborn Attachments ,” economist Tyler Cowen offers a brief thought experiment meant to illustrate how seemingly tiny differences in GDP growth rates generate massive wealth differences over time. What if, Cowen asks, the US economy grew at one percentage point less annually from 1870 through 1990?

Source: Is infinite economic growth a fantasy? Or is the fantasy the idea that we are quickly using up the Earth?

Chloroquine and SARS

Not for COVID-19, but for the 2005 SARS outbreak. Suddenly, in light of this, hydroxychlorquine sounds a lot more reasonable.

Chloroquine is a potent inhibitor of SARS coronavirus infection and spread

Background

Severe acute respiratory syndrome (SARS) is caused by a newly discovered coronavirus (SARS-CoV). No effective prophylactic or post-exposure therapy is currently available.

Results

We report, however, that chloroquine has strong antiviral effects on SARS-CoV infection of primate cells. These inhibitory effects are observed when the cells are treated with the drug either before or after exposure to the virus, suggesting both prophylactic and therapeutic advantage. In addition to the well-known functions of chloroquine such as elevations of endosomal pH, the drug appears to interfere with terminal glycosylation of the cellular receptor, angiotensin-converting enzyme 2. This may negatively influence the virus-receptor binding and abrogate the infection, with further ramifications by the elevation of vesicular pH, resulting in the inhibition of infection and spread of SARS CoV at clinically admissible concentrations.

Conclusion

Chloroquine is effective in preventing the spread of SARS CoV in cell culture. Favorable inhibition of virus spread was observed when the cells were either treated with chloroquine prior to or after SARS CoV infection. In addition, the indirect immunofluorescence assay described herein represents a simple and rapid method for screening SARS-CoV antiviral compounds.

Virology Journal 2005; 2: 69

Code Review of Ferguson’s Model

Conclusions. All papers based on this code should be retracted immediately. Imperial’s modelling efforts should be reset with a new team that isn’t under Professor Ferguson, and which has a commitment to replicable results with published code from day one. 

On a personal level, I’d go further and suggest that all academic epidemiology be defunded. This sort of work is best done by the insurance sector. Insurers employ modellers and data scientists, but also employ managers whose job is to decide whether a model is accurate enough for real world usage and professional software engineers to ensure model software is properly tested, understandable and so on. Academic efforts don’t have these people, and the results speak for themselves.

Lockdown Skeptics .org

Heartland launches 22 climate science “gatebreakers”

The Heartland Institute has just published a whopping 22 gatebreakers, with more promised. This is a true wealth of important skeptical material, unlike anything we have seen before. My dream is coming true.

A gatebreaker is something a skeptical student can send around to the class when the teacher insists on alarmism. Or something short and simple to send to a journalist in response to an alarmist article, or to a politician making alarmist speeches, or the local blowhard alarmist. It’s power lies in its specificity and its simplicity.

The Heartland website is called “Climate at a Glance” (https://climateataglance.com) which makes it sound softer than it really is, sort of like a pink pistol which you can actually buy. These are not glances; they are hard hitting rebuttals.

Resources and Earth Day

Resourceful Earth Day also signals a hope more appropriate to spring, marking a return to a positive view of man’s role on this planet. Indeed the old Marxists, convinced that they would dominate the future, optimistically favored economic and technological change. The forces of change, they believed, would move man toward heaven here on Earth.

That optimistic element has disappeared. The environmental establishment has grown increasingly gloomy, convinced that the Earth is suffering from the “Terrible Toos” — too many people, too much consumption, too great a reliance on technology which is understood too little. Earth Day has become a day of atonement for man’s criminal assault on our planet. That pessimism reflects, in part, their realization that history is no longer on their side; thus, change is no longer in their interest. Stasis must be the order of the day.

With attacks on things like biotechnology, automobiles, suburban opportunity and trade, they now seek only, as Aaron Wildavsky noted, “an egalitarian society based on rejection of economic growth in favor of a smaller population eating lower on the food chain, consuming a lot less, and sharing a much lower level of resources much more equally.”

Master Resource

The problems of famine, overpopulation, poverty and disease are resolvable. In fact, they have been resolved in the United States and other places where human ingenuity is free to solve them. The calamity criers of the green movement predicted great disasters afflicting the planet by the year 2000. The Carter administration’s Global 2000 Report forecast global calamity, and Paul Ehrlich claimed on the “Johnny Carson Show,” “If I were a gambler, I would bet even money that England will not exist in the year 2000.”

Unfortunately for the eco-catastrophists, as we approach their due date for disaster, the planet is in increasingly good shape. This point was recently conceded by America’s arch-druid. “Not only do we have the healthiest economy in a generation,” said Vice President Al Gore, “we also have the cleanest environment.”

On this Resourceful Earth Day, we may hope that Gore and his fellow foot soldiers in the environmental brigades will ponder these points and rethink the wisdom of the current policy of placing all one’s faith in federal political solutions. The greens’ constant calls for massive government controls, forced population limits, harsh curbs on economic activity, and a curtailing of technology threaten to produce exactly the results that such actions seek to avoid —a world of ecological and economic disaster. On this April 22, let us commit to both a freer and a cleaner world; they go together after all.

ibid

And there’s also this piece by Julian Simon:

During the first great Earth Week in 1970 there was panic. The public’s outlook for the planet was unrelievedly gloomy. The doomsaying environmentalists–of whom the dominant figure was Paul Ehrlich–raised the alarm: The oceans and the Great Lakes were dying; impending great famines would be seen on television starting in 1975; the death rate would quickly increase due to pollution; and rising prices of increasingly-scarce raw materials would lead to a reversal in the past centuries’ progress in the standard of living.

The media trumpeted the bad news in headlines and front-page stories. Professor Ehrlich was on the Johnny Carson show for an unprecedented full hour—twice. Classes were given by television to tens of thousands of university students.

It is hard for those who did not experience it to imagine the national excitement then. Even those who never read a newspaper joined in efforts to clean up streams, and the most unrepentant slobs refrained from littering for a few weeks. Population growth was the great bugaboo.

Every ill was the result of too many people in the U. S. and abroad. The remedy doomsayers urged was government-coerced birth control, abroad and even at home.

On the evening before Earth Day I spoke on a panel at the jam-packed auditorium at the University of Illinois. The organizers had invited me for “balance,” to show that all points of view would be heard. I spoke then exactly the same ideas that I write today; some of the very words are the same.

Of the 2,000 persons in attendance, probably fewer than a dozen concluded that anything I said made sense. A panelist denounced me as a religious nut, attributing to me weird beliefs such as that murder was the equivalent of celibacy. My ten-minute talk so enraged people that it led to a physical brawl with another professor.

Every statement I made in 1970 about the trends in resource scarcity and environmental cleanliness turned out to be correct. Every prediction has been validated by events. Yet the environmental organizations and the Clinton administration–especially Vice President Al Gore, the State Department, and the CIA –still take as doctrine exactly the same ideas expressed by the doomsayers in 1970, despite their being discredited by recent history. And the press overwhelmingly endorses that viewpoint.

Here are the facts: On average, people throughout the world have been living longer and eating better than ever before. Fewer people die of famine nowadays than in earlier centuries. The real prices of food and of every other raw material are lower now than in earlier decades and centuries, indicating a trend of increased natural-resource availability rather than increased scarcity. The major air and water pollutions in the advanced countries have been lessening rather than worsening.

In short, every single measure of material and environmental welfare in the United States has improved rather than deteriorated. This is also true of the world taken as a whole. All the long-run trends point in exactly the opposite direction from the projections of the doomsayers. There have been, and always will be, temporary and local exceptions to these broad trends. But astonishing as it may seem, there are no data showing that conditions are deteriorating.

….

Julian Simon’s 25th anniversary essay

Homemade filters

In college, I encountered a list of improvised filters that could be used to guard against inhaling radioactive contamination. I haven’t been able to find that list, but here’s something from the Wall Street Journal: Will homemade filters protect against the coronavirus?

A coronavirus particle is about 0.12 microns, or an eight millionth of a meter. Different materials have been tested for their ability to screen out virus particles.

  • Furnace filters — 98%
  • Automotive filter — 95%
  • Vacuum bag — 90%
  • Swiffer dry sweeping cloth (five layers) 60%
  • T-shirt fabric (five layers) 60%
  • Bed sheets (five layers) 50%
  • Paper towels (five layers) 40%
  • Coffee filters (two layers) 10%

Source: Do DIY Masks Help Stop Coronavirus?

It’s Too Darn Hot

I’ve been slowly collecting notes on the science that science fiction writers get wrong. I have this idea of using them for the basis of a high school level science class. In fairness, I don’t count things like the swamps of Venus or the notion that Mercury’s dark side never faced the sun and was perhaps colder than Pluto. I intend to focus on things that were known at the time a story was written. For example, the notion that gravity would hold structures and an atmosphere against the inside surface of a Dyson sphere.

One thing that crops up from time to time in science fiction stories is helium-II on very cold planets. Pluto is one target. Or imagine a planet that’s tide-locked with its sun, with the dark side near absolute zero. You could imagine streams of superfluid helium flowing uphill because that’s what superfluids do.

Well, it occurred to me to look up the temperature at which liquid helium transitions to superfluid helium-II. This temperature, the so-called lambda point, is 2.1768K, or 2.1768 Celsius degrees above absolute zero.

The cosmic microwave background corresponds to a temperature of 2.7255K, or nearly half a degree above the lambda point for liquid helium. That means a body floating in interstellar space will exchange heat with the surrounding sky by radiation until its temperature is equal to the microwave background temperature. As a result, the planet will remain too hot for superfluid liquid helium to exist.

So good-by superfluid helium based life forms.

Since then, I’ve read that the temperature can be lower inside dust clouds, where the energy from the microwave background hasn’t had time to penetrate into its depths. And that could be the basis for an interesting story.

Nevertheless…

It’s too darn hot.

It’s too darn hot.

I’d like to go superfluid tonight,

And flow against gravitation tonight,

I’d like to be superfluid tonight,

And flow uphill over walls in the night,

But I ain’t down to transition tonight,

‘Cause it’s too darn hot