Date: April 14th, 2010
Cate: research
1 msg

Material Flow Analysis of Polyethylene Terephthalate (PET)

My first industrial ecology paper has just been accepted for publication in “Resources, Conservation, and Recycling,” titled “Material Flow Analysis of polyethylene terephthalate in the US, 1996-2007.” Polyethylene terephthalate (PET) is the “#1″ plastic material used to make bottles for soda and bottled water, as well as a steadily increasing stream of clamshell containers. It’s the most-recycled plastic. (update: available online as of May 15, 2010: doi:  10.1016/j.resconrec.2010.03.013).

Here’s the abstract:
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Date: February 25th, 2010
Cate: admin
2 msgs

I’m legit — honest!

ocean.301south.net is a low-volume mail server. 95% of my logs are spam rejected by postgrey.  The other 5% are evenly divided between spam which gets screened out by SpamAssassin and actual legitimate messages, which probably number 25 a day coming in and fewer than 10 a day going out.   So you can imagine my dismay when Yahoo(!) refused to accept an email from Abbie to her mother on the basis of my server’s reputation.

There’s obviously an element of inferiority-complex here.  In a world where everyone is known by his google ID and it’s all but impossible to acquire a static IP address, I am in the extreme (maybe even six-sigma) minority to be administrating my own e-mail server.  I hold a physical copy of all my emails on my home server (and Abbie’s, too) and I never see ads.

But lately, particularly since moving from a DSL connection to a Cable connection (hosted by Cox Business), I’ve started to notice that emails from my domain were frequently spurned, often winding up in spam folders or being rejected altogether, particularly by Yahoo servers.

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Date: February 16th, 2010
Cate: politics
1 msg

Drawing a line for the denialists

With the unending avalanche of embarrassments in climate science recently, global warming “deniers” are becoming ever more strident in their triumphalism over defeat of the “warmists.” I must admit that I have not familiarized myself with the science behind the IPCC report.  But there is a simple, irrefutable fact that those committed to rational inquiry must not lose track of, and that is that we have been pumping a hell of a lot of carbon dioxide into the atmosphere.

This can be corroborated with CO2 measurements from around the world and is really not contested.

However, some people seem to still believe that this change could not be caused by human activity.  Here I present a simple, back-of-the-envelope computation to measure the total weight of CO2 in the atmosphere, compared to the total weight of CO2 released by burning fossil fuels. more))

Date: February 8th, 2010
Cate: engineering, research

Curve-fit with zero offset

Say you are measuring some signal, which you expect to show an exponential decay, but you are unsure of the zero-point on your measuring device. If you want to measure the time constant of the decay you need to know what it’s decaying to. For a signal s,

s=s_{0}+A_0\exp(-t/\tau)

In order to do conventional least-squares fitting to A_0\exp(-t/\tau) you need to determine s_0.

Step response of NIH 3T3 fibroblasts to ionomycin

Step response of NIH 3T3 fibroblasts to ionomycin


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