Gas station without pumps

2015 August 28

New Stem Cell Assistant Professor position

Filed under: Uncategorized — gasstationwithoutpumps @ 22:07
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UCSC has just announced a new Assistant Professor position in Stem Cell Genomics in the Biomolecular Engineering Department.  The job description and application is at, and the key line is probably

The successful candidate will be expected to establish a wet lab operation focused on stem cell genomics research, to develop a vigorous, externally funded research program, contribute significantly to undergraduate and graduate education, and perform university and professional service.

We are defining stem-cell genomics fairly broadly, particularly the “genomics” part—the stem-cell part is an absolute requirement, as the available lab space is dedicated to stem-cell research.  The “genomics” is there because that is where the department has critical mass—it will be easier to integrate a genomics person into the department than someone who is further afield.  That said, we always look for the best available candidate using a broad definition of what the position calls for.

Personally, I am hoping that we get someone in stem-cell engineering, as we are an engineering department, not an extension of the Molecular, Cell, and Developmental Biology department.  I’m not on the search committee, though, and I don’t know whether they share my view of the importance of strengthening the engineering and design components of our curriculum and teaching—they may not even distinguish between science and engineering.

I’m not in stem cells myself, so I’m not up-to-date on what is going on in the labs.  As I understand it, current research is mainly with mice (particularly hematopoietic stem cells), but there are a number of new induced pluripotent stem cell lines being established for various primates.  (A couple of the senior theses that I read several times as part of senior thesis writing courses dealt with establishing iPSC lines from orangutan fibroblasts.)

This faculty slot is the last wet-lab person the department will be able to hire for some time (until the campus rationalizes their currently dysfunctional way of allocating space—we are desperately short of wet-lab space while other departments are trying to figure out what to do with all their unused wet-lab space), so we want to get someone good who’ll stay with us for a long time.

It is an assistant-professor-only slot (tenure-track, but arriving with tenure)—the department has wasted way too much time on failed senior recruitments (generally forced on us by higher administrators—the School of Engineering has done much better growing our own faculty from promising assistant professor candidates).


2015 August 26

Few Santa Cruz businesses on bike league list

Filed under: Uncategorized — gasstationwithoutpumps @ 10:23
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Every year the League of American Bicyclists publishes a list of “bicycle-friendly businesses”, which employers (including governments and non-profits) can apply to be on.

I was surprised at how few Santa Cruz employers were on the list:

  • Ecology Action (silver)
  • County of Santa Cruz (bronze)
  • Santa Cruz Seaside Company (bronze)

The League also has listings for communities, universities, and states.  The City of Santa Cruz has a silver listing, as does UCSC. UCD is platinum; UCSB is gold; UCB and UCI are also silver; UCLA and UCSD are bronze.  UCSB and UCD are also listed as businesses (their bike-friendliness towards employees, rather than towards students), with the same ratings.

UCSC does do a fair amount for bicycle commuters. I know of free showers in at least 4 buildings on Science Hill, and there are probably others. Most buildings allow people with offices to bring their bikes into their offices and there are card-operated bike lockers next to some of the more popular buildings.  Bike posts and other low-security bike parking are provided in adequate quantity (though the quality is not aways the best).  There are free tool stands at several places on campus and an on-campus bike shop (the Bike Co-op, which is not a full-service bike shop).  All the campus buses and the SCMTD buses that serve campus have racks for 3 bikes, and UCSC runs an uphill-only shuttle with a trailer for a dozen bikes from the Westside several times an hour.

Having seen what UCSB does, it looks like the main differences in bike friendliness come from UCSB’s campus being flat and compact, while UCSC’s is sloped at 4% and spread out.  The ravines and hills on the UCSC campus make it very expensive to provide additional roads and bike paths, and the 4% climb for a mile from the entrance to campus to Science Hill is daunting for many beginning bicyclists.

UCSC could do more to promote bicycling to campus, but there is a point where even large investments result in only small increases in bicycling—UCSC has invested much more heavily in transit options than in bicycling, as they expect that to make larger changes in student and employee behavior.  (And it seems to be working—UCSC has tripled in size in the last 30 years, with only modest increases in motor vehicle traffic.)

I don’t know whether Santa Cruz has been slipping as a bike-friendly place, whether other places have overtaken Santa Cruz, or whether businesses and governments in Santa Cruz simply can’t be bothered with the bureaucratic process of the League’s classification scheme.

What is the return to the community if more businesses were listed as bike friendly, or the community rating were higher? The listing is primarily a marketing tool—from a bicyclist perspective, what matters is what the infrastructure and policies are, not whether the LAB knows about them. And marketing is not that valuable to the community right now. It isn’t as if Santa Cruz were trying to lure more people to move here—we already have a serious housing crunch, particularly for the rental market. (Prices are high also: studio apartments are about $1600 a month, 2-bedroom about $2200 a month, I think.)  I do think that Santa Cruz would benefit from more ecotourism marketing—getting tourists to bicycle around town rather than clog the streets with their bad driving would be an improvement.

What Santa Cruz is trying to do is to lure more tech companies to Santa Cruz, to take advantage of the highly educated people already here and reduce the long-distance commuting to high-paying jobs in Silicon Valley. It is not clear whether getting a better bike-friendly community rating would help with that effort or not, though one of the big attractions for tech workers in Santa Cruz is not having to do the Highway 17 commute.  Being able to bike to work is a big attractor for engineers, particularly in software businesses (it is often our only source of exercise).  Whether it is an attractor for tech companies is a somewhat different question.

2015 August 22

Don Cohen, Calculus by and for Young People: 1930–2015

Filed under: Uncategorized — gasstationwithoutpumps @ 08:58
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I just found out that the author of Calculus by and for Young People died this year:

Donald “The Mathman” Cohen was a great educator and influenced thousands of children and adults throughout his life. He began teaching in the 1950s and continued his work through The Math Program which started in 1976 in Champaign/Urbana, IL with partner Jerry Glenn. Don continued teaching right up until he passed away in 2015 at age 85. Don’s books and other materials continue to be treasures for all who are interested in math or math education.[Don Cohen – “The Mathman” – 1930-2015]

His family is making his books available as free PDF downloads, as a memorial: Don Cohen – “The Mathman” – 1930-2015

We didn’t use his books (by the time we found out about them, our son had already acquired enough calculus not to benefit from the books), but lots of kids did get an early start on calculus using them.  He aimed is material at middle school students, rather than college students. His approach to teaching math seems to have been highly regarded both by math teachers and in home-school circles. More info about his math program at his web page.

2015 August 18

Meta Mode Kinetics sale

Filed under: Uncategorized — gasstationwithoutpumps @ 16:33
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I just got email from Futuristic Lights—they are having a one-week sale on Kinetics with “Meta mode”, which was a special feature of the Limited Edition Kinetics.  The new meta mode is slightly different, so as not to duplicate the Limited Edition lights.

Meta Mode Kinetics

We heard the demand for us to release Meta mode again. We decided to give everyone a chance to purchase a set of Meta mode Kinetics for one week only! From now through the weekend you can snag a set of our redesigned Meta mode Kinetics that features a lowered speed threshold, and an increased space in the last dops pattern to give it a fresh new look that we think you are all going to love. Don’t forget to add extra batteries to your order for a slight discount!

Click on the big Meta Mode Kinetics to go to their sale page.

I wonder whether this one-week sale will give their sales a nice kick this week. I think that they need some more sales to bankroll their next product.

2015 August 10

I’ve got solar power

Filed under: Uncategorized — gasstationwithoutpumps @ 20:14
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This summer I finally bowed to my wife’s wishes and had solar panels installed on our garage.

They make no sense economically—our electricity bill is only $420/year and the panels cost us about $20k—for a payback period of about 45 years (it will be a little less after tax rebates).  Of course, that ignores the maintenance costs—the inverters aren’t designed to last 45 years and will need replacing well before then, and the panels need to be cleaned once or twice a year.

We don’t use a lot of electricity (usage before solar installed):

Pattern of electricity use by month.  Far more electricity is used locally in the winter for lighting than in the summer—air-conditioning is rare here.  My peak usage was 300kWh in January and my minimum was 163kWh in May.

Pattern of electricity use by month. Far more electricity is used locally in the winter for lighting than in the summer—air-conditioning is rare here. My peak usage was 300kWh in January and my minimum was 163kWh in May.

Our solar installation has 8 Sunviva Optimus 270-60-4-1B0 60-cell panels, each nominally 270 W, but the highest output I’ve seen from one is 237W.  The observed peak is less than the rating, because the panels are not getting 1000 W/m2 at 25°C, which is what the panels are tested at. The panels are not optimally oriented to the sun, so they get somewhat less light per square meter (multiply by the cosine of the angle from the optimum). Even if they were getting 1000 W/m2, with that much sun they’d get pretty warm, and the maximum power drops by about 1/8th to below 240W at 50°C.

One interesting observation is that peak power occurs right after dips due to cloud cover—I think that the panels warm up quickly in full sun, and the solar cells are less efficient when they are warm.

The Enphase M250 microinverters are rated for 240W continuous (250W peak), so are a good match for the panels.

The panels are not oriented optimally for solar power, because it is cheaper for installation and maintenance to mount them flat on the garage roof and buy more panels than to make complicated roof racks to get them to the optimal orientation. The garage is oriented so that one half of the roof faces southeast and the other half northwest. The highest peak power is on the southeast half, but the maximum energy generation is on the northwest half, because morning fog limits the sunlight from the east, but afternoons are usually clear, so the northwest panels generate power for longer.  Around 1:20pm, both sets of panels are illuminated, and I get a peak power of about 1.57kW (~210W from each southeast panel and ~185W from each northwest panel).

The west-facing panels generate more power and more valuable power, because I have time-of-use service, and peak power costs 30¢–32¢ a kWh (90¢–92¢ on SmartDays™), while morning part-peak costs only 18¢–21¢.

The panels are generating about 10kWh per day (at the beginning of August—I expect about 30% of that in winter on good days, and far less on rainy days). Note: total insolation for Santa Cruz is about 7.41 kWh/m2/day in June and only 1.99 kWh/m2/day in December [], so minimum winter production at 27% of peak summer production seems reasonable. The average insolation over the year is 4.764 kWh/m2/day, so I expect to average 7 kWh/day over the year (maybe a bit less for bad weather),

Based on these estimates, I expect to generate about 2.5MWh a year, and I use about 2.6MWh a year, so there will be only small net usage or surplus. PG&E will buy any surplus electricity for about 4¢ a kWh.  An astute follower of the solar market may wonder why our system cost so much. Well—it’s complicated.  We were putting the solar panels on our garage roof, but the shingles there were within 5 years of their expected lifespan, so we ended up reroofing the garage. And the city wouldn’t give us a permit for the solar installation unless we replaced the 60-year-old fuse box, added bigger grounding rods, put the electric feed to the house above the roof line, … .  So we ended up with a much bigger project than just adding solar, coming to about $10/W, rather than the more expected $5/W.

I’m not certain about the details of PG&E’s net metering scheme, but I think that if we use electricity at peak times on one day, we get charged full price for it, even if we generate excess electricity at peak times on other days. It would be fairer to have net computations take time-of-use and time-of-generation into account, so that net peak use is computed, with any surplus credited to part-peak, then net part-peak computed, with any surplus to off-peak, then final net computed. But I don’t think that there is any day-to-day carryover of peak surplus power. I’ll have to check the net energy metering contract very carefully to figure out the exact rules.

Of course, total energy use for the house is much larger, since we heat the house, heat water, cook, and dry clothes with natural gas. My natural gas use is about 433 therms/year, which translates to 12.7MWh, about 4.9× my electricity use. So the solar panels don’t make the house energy neutral. Even if we do generate some surplus electricity, switching some usage from natural gas to electricity doesn’t make economic sense, as natural gas costs about $1.28/therm or 4.4¢/kWh, only slightly more than PG&E would pay for the surplus electricity.

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