omenti

how much would someone pay for a low carbon dioxide SAT testing location?

I was in a fourth floor office on the extreme Eastern end of the installation.  The view was great, fantastic colleagues, interesting puzzles and questions ...  the problem was something smelled wrong.  Nearly two months had passed since I moved to the downgrade and it was time to get serious.  A massive retrofit to Bell Labs buildings 1 and 2 at Murray Hill, the downgrade was an external corridor five stories high and over eight hundred feet long intended to bring location infrastructure up to date as well as to improve energy efficiency.¹  

 

Office buildings need to have their airflow balanced to keep the air fresh and prevent the buildup of undesirable pollutants.  My office airflow was poor and there was an ever present chemical background smell.  In theory it had been adjusted twice, but I wasn't seeing any change.  I needed help and that meant doing a bit of trading.  Murray Hill had something of an underground economy that was very useful when dealing with the trades.  Many of these people were extremely good at what they did, but it was a union shop with strict scheduling and work rules.    A variety of currencies were used, I was part of the baking economy.

 

Tony got a blueberry pie. He had access to some serious air monitoring kit and was more than happy to come down with two portable racks.  Unsurprisingly we found a variety of volatile organic compounds and stagnant airflow in most of the office.  What surprised me was a carbon dioxide reading of about 1,600 ppm.  I knew that too much was not a good thing, but had no idea what the limits were.

 

After some searching it became clear that values over about 5,000 were considered dangerous, but tests suggested lower limits were in order.  The standard for HVAC systems was to try to keep levels under 1,000 ppm - about 650ppm above atmospheric levels at the time.  1,000 still appears to be the target number.

 

I needed an airflow expert.   I knew from experience Sal was a chocolate chip cookie guy.  It took nearly three days of on and off adjustments along with replacing the tiles in the ceiling and floor to replace with a special nonvolatile variety earmarked for the executive offices. (he really liked my baking) VOCs came right down and he managed to get CO₂  tracking between 475 and 550 ppm.

 

Years before there was the Brookhaven house. During the late 70s some work was done on passive solar homes as a response to the energy crisis - at the time a large percentage of homes in the Northeast were heated with imported oil.  The idea was to link architects with physicists and material scientists and anyone else with an interest to see if a normal looking home could be built for about the same price as a conventional home, but with annual heating, cooling and hot water energy costs under $100

 

The house easily exceeded its energy goals.  Mostly it was used for testing, but at times people could stay there.  The problem was it was sealed so tightly that you noticed the stale air and felt uncomfortable.  Better heat exchangers that allowed more air circulation needed development and, if necessary, it was better to leak a bit of air to keep indoor pollution levels low.  This is largely a solved problem these days, but I spent some time in the house and its problems started me to think about the problem. 

 

Over the years studies came out showing that indoor air was often much worse than some of the most polluted cities on the planet.  A few of the studies looked at cognitive problems.  CO₂ was particularly interesting as most large building HVAC systems measure it.  Some studies suggest that cognitive impairment begins around 1,000 ppm, but others suggested lower thresholds - some in the 600 to 800 ppm range.  I'd venture a guess that, unless you're outside,  where you're sitting is above 600 ppm.

 

Getting these studies right is very difficult as office and school environments have very dynamic atmospheres.  Cognitive studies add a level of complexity.  Recently a robust study was published in Environmental Health Perspectives.

 

It studies at VOCs and CO₂ levels in office environments and suggests fairly dramatic improvements can be had.  The disturbing note, something that needs further verification, is statistically significant cognitive impairment occurred at levels commonly found in offices and school  - 950 ppm.  Impairment increased with increased concentrations and was very noticeable at 1,400 ppm.

 

from the conclusion

...

Office workers had significantly improved cognitive function scores when working in Green and Green+ environments compared to a Conventional one. Exposure to CO₂ and VOCs at levels found in Conventional office buildings was associated with lower cognitive scores compared to levels in a Green building. Using low emitting materials, which is common practice in Green buildings, reduces in-office VOC exposures. Increasing the supply of outdoor air not only lowers exposures to CO₂ and VOCs, but also exposure to other indoor contaminants. Green building design that optimizes employee productivity and energy usage will require adopting energy efficient systems and informed operating practices to maximize the benefit to human health while minimizing energy consumption. This study was designed to reflect indoor office environments in which large numbers of the population work every day. These exposures should be investigated in other indoor environments, such as homes, schools and airplanes, where decrements in cognitive function and decision-making could have significant impacts on productivity, learning and safety.

...

 

It needs to be stressed that much more work needs to be done, but if you spend your time with cognitively demanding tasks you may want to have a conversation with your building's HVAC engineer to measure and possibly adjust your office VOC and CO₂ levels.  There are some groups that worry about this.  Are organizations being handicapped with high levels of indoor pollution?  What happens when people are better equipped to measure this on their own?²

 

And the subject line...  if your kid was taking the SAT and lower carbon dioxide levels were an extra cost option, how much would you be willing to pay?

 

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¹ An aerial view of Bell Labs Murray Hill.  My office was at the location marked by the red arrow.  The transistor was invented in several labs roughly where the yellow arrow points on the fourth floor.  The retrofit was called the upgrade, but most of us called it something else.

² This is a tough question.  It is likely that low cost meters that talk to, or are even built into, smartphones will appear.  We're seeing that now with PM2.5 measurements in China now and has had a big impact on government decision making.  Any measurement needs to be understood in terms of accuracy and repeatability as well as the context of where and how it was taken.  Getting this right for many of these measurements is a challenge.  I worry that a flurry of low quality tools and measurements may cause more problems than they solve in the beginning.  At the same time having thousands or millions of people making environmental measurements in their homes, offices and cities may force large amounts of change on law makers and the legal process.

 

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Recipe Corner

 

Very easy - try variations.  I make this and variations all Fall and Winter.

 

Roast Green Beans

 

Ingredients

 

° 1 pound fresh green beans

° 2 tbl olive oil

° 1/2 tsp kosher salt

° 1/2 tsp freshly ground pepper

° 1/4 cup slice almonds, or pecans

° 1/4 cup dried cranberries.

 

Technique

 

° preheat oven to 425° F

° snap off the ends of the beans. Put them in a large bowl and toss with oil, salt and pepper.  Spread the coated beans on a rimmed pan/

° roast for about 15 minutes

° remove the pan and sprinkle the nuts and cranberries... return to the oven and roast for another 5 minutes or so.

° adjust the seasoning if necessary and serve.

 

making ice and staying warm

Benton Lake on the Bootlegger Trail was one of my three standard observing sites.  Great Falls, with about 60,000 people, had too many lights for amateur astronomy so I had to drive to find a dark sky.  Over time I came to learn Benton Lake's microclimate.  On clear nights from May to October the wind would often drop to dead calm a few hours before dawn and the atmospheric turbulence would drop making the sky very transparent.  It was worth reasoning with the alarm clock at 2am. (the area also preserves a lot of real prairie - something rare these days - along with some great bird watching.  The dawn chorus on the lake in the Summer is amazing)

 

These transparent nights often felt chilly - much cooler than it had been a few hours before.  I'd be dressed for the cold, but you would feel it on your face.  The air temperature could be 45°F, but it almost felt like freezing.  One night I looked up at the sky holding a notebook to estimate a distance.  My face felt warmer.  Moving the notebook away instantly brought the cold back.  Radiation cooling.

 

Physics tells us heat moves from warmer to cooler bodies.  It can be transferred by conduction when the bodies are in contact, by convection when a fluid like air or water transfers the heat or by radiation.  In this case we're talking about thermal radiation - any object with a temperature above absolute zero gives off electromagnetic radiation - the wavelengths are determined by the temperature of the object.   You happen to be a radiant being.   Your skin gives off infrared light in a spectrum that peaks with a wavelength around 9.4 microns - compared to visible light which ranges from 0.4 to 0.7 microns.¹  Standing outside my skin was losing heat mostly to local air - mostly moisture in the air.  On very transparent nights there is little moisture in the air.  Some of the radiation from my face gets transferred directly to space, which is very cold.  By holding up the notebook I'm sending my heat to the notebook rather than space.  

 

This was neat.  I measured a nearly 10°C temperature drop from air temperature.  For fun I decided to see if I could make it.  I made a shallow insulated basin out of an old pan that I surrounded with straw and styrofoam - anything I could find to insulate it from the warmth of the ground.  My Montana record for making ice is an air temperature of 6°C - about 43°F.² 

 

Although radiation heat transfer is an important mechanism for transferring heat, we tend to think of convection when it comes to home heating.   I'm reminded of that now with our first heating days of the season and  some video calls with a friend in London.  Her place has poor heating and she's often buried under a blanket or some other form of insulation.  I'm warm enough with a furnace and forced air heating, but it heats a large volume that is mostly unused.  

 

A variety of fixes are possible.  With new housing it is now possible to create very comfortable spaces with very little additional energy input.  The problem is these designs require new construction and house lifetimes are close to a century.  Most of us will never have that option.  Instead we look for easy fixes.  

 

The first order of business is to find air and seal air leaks - they're a convective loss. Weatherstripping is inexpensive and easy to apply.  Microclimates can be created in rooms where you tend to sit - in the 19^th century screens were used to block air loses and people sat in hooded chairs facing a fireplace.    Expanses of glass, if they aren't taking in a lot of sunlight, allow heat to transfer from objects in a room to the colder outside.  Insulated glass is expensive and not terribly efficient, but curtains work well - particularly at night. 

 

Using less convention heating and more radiation.  Usually this means electric IR heaters with glowing elements.  They use short wave infrared radiation - it can burn human skin is generally uncomfortable.  In the past decade longwave IR heaters have appeared. They put out heat close to body temperature and are quite safe.  A huge advantage is you can point them at an area where you happen to be living.  They're finding use in some exercise and yoga establishments - usually in the ceiling looking down or on walls.  

 

That leaves nanoclimates.  ARPA-E has several projects that try to heat or cool where people are rather than unoccupied areas.  There are some exotic ideas like active and passive smart fabrics, but in the meantime you can build your own nanoclimate using the conventional technology of insulated clothing.  Room temperature is usually quite a bit cooler than our skin temperature, but feels comfortable given the metabolic heat our body needs to get rid of and the average amount of clothing we wear.  By wearing extra insulation you can turn the thermostat down and remain comfortable.

 

I've done a bit of hunting but there doesn't appear to be much research documenting indoor Winter temperatures in the years since WWII.  The little that has been written suggests shirt sleeve temperatures for sedentary behavior is recent - perhaps only during the past 30 years.  In Northern Europe sweaters were almost universally used indoors as recently as the 70s.   

 

Air happens to be a poor conductor of heat, so trapping it close to the skin creates a good insulator.  In fact the insulating property of clothing can be measured.  The most popular unit is the clo (guess where the name came from?).  It isn't a standard, but is easy to understand - 1 clo is the insulation equivalent of underwear, socks, and a business suit.³ 

 

You can get into the calculations, but sitting and watching TV might be comfortable at 21°C (70°F) with 1 clo of clothes.  Assume part of that is a heavy sweater (about 0.3 clo) - take that away and you need nearly 24°C (75°F) to remain as comfortable.  Long underware is great - about 0.7 clo. You should be ok watching tv in good comfort at 17°C.  Here you have to think about warm socks or booties.  Cooler still perhaps a warm cap.   The other trick is to be physically active.  Don't worry about calculating values - just experiment!⁴

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¹ The spectrum for a blackbody at skin temperature.  You're not a blackbody, nothing is, but this is close enough.  This can be detected with infrared cameras which color code different wavelengths giving a sense of surface temperature.

 

There is a very strong temperature dependence in this curve ~ T⁴.  To calculate heat transfer you get some constants times (T⁴_hot - T⁴_cold).  Note that you need an absolute temperature scale where T_{absolute zero} = 0° ...  the Kelvin scale is appropriate. 

² I suspect I was doing even better one night in Taos.  It was late Spring with a strong of beautifully still and transparent nights.  I borrowed a pan and insulated it to the consternation of the B&B host.  I couldn't verify the air temperature, but there was  excellent ice production with a likely air temperature above 40°F.  Much more fun than the conference.

If you live in an area where this happens frequently it would be possible to build a more powerful 'freezer' - just increase the area of sky visible to the water container.  Think about a solar stove, except now the heat is transferred from the pot to the sky.

³ Roughly.  It is formally defined as a thermal resistance of 0.155 m²K/W.  Europeans use something similar called a tog (again, guess where the name came from) which is about 0.65 clo.  You can also compare it to R values - 1 R is 1.137 clo.  

Many clo values for conventional clothing (not exotic thermal underware)

⁴ There are new fabrics that are much warmer, more flexible and comfortable per unit weight than even a decade ago.  Check into outdoors clothing and look into what sedentary outdoor types (hunters) wear underneath their coats.  Some have clo values of 0.6 and adding a second layer traps even more air than two single layers given a combined value of 1.5. Wear this under normal clothing or even with a sweater and you can survive in a very cold room.  I used this approach to survive Sandy and an indoor temperature that dropped to 47°F (about 8°C) - not much warmer than the average refrigerator.  You do need a cap at these temperatures. 

I find a heavy sweater combined with modest moving around (not much more than being sedentary works well at 68°F.  At night I can drop to 62° at night with normal bed covers.  The fact leaks have been mostly sealed makes this even more comfortable.  When guests are over the heat gets cranked up to 72° - you get used to the lower temperatures.

In the US the idea of conserving in the home or while driving became a political issue around the time of Jimmy Carter.   Given the amount of personal conservation practiced during and before WWII there are probably some very interesting cultural issues at work.

 

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Recipe corner

 

Some comments on processed meat, red meat and cancer. This is old news.  Both processed meat and red meat have associated with increased cancer risk, but suggesting a causal link is extremely difficult in human studies.  Something has to have a very high mortality rate or have a good association over many studies and even generations of subjects to be considered causal.  At the same time other genetic risks tend to be much greater and probably modulate dietary risks.  The bottom line is that eating these foods may well elevate your risk, but that is a probability.  The risk elevation was found to be 18% if you regularly have about two ounces of prepared meat.  In real risk your chance of getting colorectal cancer goes from about 4.5% to 5.5%.  

Unless you have other risk factors the only behavior change may be between none and moderation.  If you're looking for an excuse to cut back on meat products, this may be a good one - otherwise just realize that all of us have a lot of risk factors with some of the largest being  out of our control.

A comment that might be useful.  Plant-based foods have been shown to be protective against cancer.  People who eat a lot of meat tend to eat less plant based foods.  The studies corrected for this, but you can improve your overall odds by moving to more of a plant-based diet.

 

 

 

moore's law and california's seasons

 

Deluge, Drought, Fire and Earthquake

California's Four Seasons   

- a plaque at Caltech

 

In the early 70s two researchers began to sift through long term weather data-sets hunting for patterns other than seasonal variation.  They had access to a late 60s super computer and a powerful processing technique called the Fast Fourier Transform.¹

 

The data set was from an isolated weather station near the equator and international date line.  Every day a weather balloon would be tracked created a time series.  An interesting pattern emerged - about every month and a half barometric pressure dropped and wind speeds picked up. It looked like the signature of a storm and was interesting enough that they analyzed data from weather stations throughout the region.  A weather oscillation in the tropics of the Indian Ocean emerged and was named for them.  Now it appears the Madden-Julian oscillation (MJO) is one of the most important weather patterns on the planet.

 

(click for animation)

Computers and computation have improved enormously in the forty years since the MJO's discovery, but only recently have they been powerful enough to enable researchers to ask questions deep enough to build predictive models.  The mechanism is far from well understood, but it appears it impacts other systems.  It is connected to Indian and Australian monsoons, the Pineapple Express and perhaps most dramatically for Californians the El Niño.

 

This year several huge warm wet disturbances have amplified the developing El Niño to produce some intense hurricanes in the Pacific as well as possibly suppressing activity in the Atlantic.  California may well be in the crosshairs of an exceptionally strong El Niño event.  It is unlikely to bring much drought relief as the snow pack is unlikely to increase much, but it could bring floods and mudslides.  Ah the seasons.

 

Outside of the research community the MJO is not well-known, but understanding it may well be central to understanding weather on the planet and its behavior in a warming world could have dramatic impacts.  But if it is only beginning to be understood now why mention it?   It turns out enough is known that the uncertainty for certain classes of events has been reduced to the point where predictions can be made.  One organization has managed to model it well enough to be able to make accurate enough cold snap predictions over a month out - far enough that traders are using it to make bets on heating fuels.

 

Science is sedimentary.  By the beginning of the 20^th century pencil and paper calculations and a few simple measurements were enough to suggest that human caused release of carbon dioxide into the atmosphere could raise the average temperature of the Earth. By the 1960s a clear signal was emerging and a few people began to make predications.  By 1980  alarm bells had gone off in the research division of Exxon and at a few University and government labs. The simple models had small enough error bars that it appeared we might be heading for some rather bad sailing.  The 90s saw a shrinkage of the error bars along with enough insight that deeper questions arose about mechanisms. Error bars shrunk and new insight and questions came. By around 2000 climate scientists had a sound enough case that most scientists in similar fields were agreeing with them.  The signs were strong enough that it was clear action was necessary, but money and politics got in the way.  

 

We won't understand nature perfectly - but there are points along the way where our understanding is sufficient to bring invention and change.  There is an art and a science in knowing how to determine when the error bars are small enough to be useful. But progress will continue and maybe we'll get a handle on each of California's seasons.

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¹ The CDC 6600 had a 10 MHz clock and 128 K of memory in the $10 million maxed out configuration.   Comparisons with current technology are difficult, but the S1 module in the Apple Watch has a clock, slowed for battery life, that is  52 times as fast and 256 K of on-chip memory cache as well as 8 GB of flash that it can access faster than the CDC.

The Fast Fourier Transform reduces the computation required for a Fourier transform from O(n²) to O(n log n) where n is the data size.  For realistic data sets this was worth decades of Moore's Law.  All of us are aware of the fantastic progress that has been made in silicon over the past six decades, but improvements in algorithms have also made an enormous contribution.

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Recipe corner

 

No recipe this time other than noting beans are a favorite.  I like some of the dried varieties from Rancho Gordo and use their basic bean cooking technique.  It will work for any mostly fresh dried beans.

RANCHO GORDO Cooking: Basic Beans from Steve Sando on Vimeo.