garden walk

morning walk around the garden. breathe!


Quarantine tripping

We’re all on a collective drug trip in this quarantine. The routines that keep us stable, that minimize our daily cognitive load, have been disrupted. Our days and actions that have been thrust upon us suddenly feel surreal. We’re staying home all day so we should have so much extra time, but we don’t feel it. We feel confused, unstable, uncertain if the things we’ve always thought we understood are true. We can either fall into existential depression, or take this opportunity to look anew, with child eyes, at where we’ve been going, what our lives mean.


N95 Respirator Microwave Decontamination Procedure

Link to the one-page nicely formatted document.

N95 Respirator Microwave Decontamination Procedure

  • Fill a plastic container with 50mL (¼ cup) of tap water
  • Place a perforated plate over the container
  • Place a single respirator on the perforated plate (so the steam can get through to it)

  • Microwave on high for 2 minutes
    • 1250W rated, 2450 MHz commercially available microwave oven
    • the metal noseband won’t spark - the water will absorb the microwave energy
  • Inspect respirator for visible signs of deterioration, and check fit remains adequate

Perform this procedure at your own risk. This procedure is not approved by the CDC, but was demonstrated on N95s in these peer-reviewed studies:

Did it decontaminate?
Did it degrade the N95 filter?
Did it degrade the N95 fit?
≥4.81 log10 TCID50 reduction in H5N1
>95% filtration efficiency after 1X treatments
not tested
procedure above
not tested
not tested
no change in fit or comfort
procedure above
>4-log reduction of viable H1N1 virus
not tested
slight delamination of nose foam cushion
procedure above
not tested
>95% filtration efficiency after 3X treatments
slight delamination of nose foam cushion
procedure above
Zulauf 2020 preprint
>5-log reduction of viable MS2 phage
no change after 20X cycles
no change in fit or comfort
procedure above, 3m
3M 2020 no peer-review
not tested
>95% filtration efficiency after 5-10X treatments
partial melting, foam delamination on some 
procedure above


Loving myself

A definition of love from bell hooks that especially resonates with me:

Love is “the will to nurture one’s own and another’s spiritual and emotional growth.” “Love is an action, not solely a feeling.” “Love as a combination of care, commitment, knowledge, responsibility, respect, and trust.”

But, someone might ask, where does that will come from? How do I know you are willing? What is it about me that makes you willing? They are seeking to understand what is good about themselves that they deserve to be loved.
But this questioning loses its weight if we accept that it is possible to be loved just for being ourselves. It is inconceivable to someone who does not love themselves that they could be loved just for who they are. And so the work of learning to love oneself is the work that must be done by the individual to free them from this thinking. Only when we learn to love ourselves can we accept the unqualified love of others. 


Are mercury emissions from satellite electric propulsion an environmental concern?

We published a paper about the environmental impact of using mercury as a propellant in massive satellite constellations.


Figure 1.

I feel proud to have authored a paper! Environmental science isn’t my usual thing, and I don’t normally publish professionally, so the experience was awkward and often frustrating. But with some help from distant collaborators and supportive friends, it’s been published finally.


Land use comparison map

This map I made shows the cumulative areas of various human industries in the USA (agricultural, mining, cities, roads) for comparison. Most crazy to me is that we use about 37,000mi^2 (about the size of Indiana) of cropland to grow corn to produce ethanol fuel. This process is extremely inefficient in terms of chemical energy out over sunlight in because it only uses the corn kernels themselves and Zea mays is not a particularly efficient photosynthesizer. It would be much better if a more efficient energy crop replaced this.


Tandem practice

Happy with my tandem paragliding progression this year. Getting better at judging conditions, briefing passengers, and launching smoothly.



Torn regarding emoji’s. On one hand, they are a crutch for emotion communication in media where we don’t take the time to craft words that do the job. On the other, they serve as important tools for reducing ambiguity in the low bandwidth medium that is text conversation.


Recognition is prejudice

Recognition is prejudice. The act of categorization, of labelling, the very capability that allows us (or any mind) to understand anything in the world, is inherently exclusionary. Who/what can or can’t be what. Limiting of possibilities. Thinking sideways allows us to fight against this.


Song by Song

Song by Song is a podcast about Tom Waits. At least one episode for every song, starting from the beginning.

hello Martin and Sam!

I'm a bit behind, so this comment is in regards to an episode from a few months back. 

I appreciated both your and Vera's thoughts on Ruby's Arms, Big Time [157], particularly in regard to the duality between the toxic masculinity embodied in the story and the quality of the song itself. 

For me, that same feeling of contrast (almost cognitive dissonance) between unfortunate lyrics and beautiful music occurs often with Springsteen, e.g. Born To Run (as Sam says, those 80's singer-songwriters!). The critical side of me reacts to the "warped idea of romantic hero figures" and escapism, but at the same time, the music arouses such feelings of hope and freedom and action!

When I think too hard about this, my brain starts making dubious connections with Zen and existential struggle...

It's tempting and self-flattering to imagine I'm somehow evolved - "an artist", or in Fitzgerald's words "a first-rate intelligence" lol - to be able to consider both facets as true simultaneously. But maybe the more sane approach is to listen to music that doesn't have a compromise. I don't know. My favorite recently is tune-yards. 

Your show is wonderful!



Arrest Documentation

Usually, I'm perfectly OK with police action - pulling over traffic violators, deterring violence, and generally enforcing the laws designed to prevent society from devolving into a commons tragedy. But I notice that the attention of peace officers often falls more heavily, in ways that seem unfair to me, on those less privileged.

I've been struggling for the last few years with my instinct to just continue on my way when I see some action (police or otherwise) that doesn't sit right. It's easy to ignore other people's problems, and likely, if I knew all the facts, I would agree with whatever the officer was doing. But often (and this I acknowledge may be an anti-authoritarian bias of mine), I feel like the officer is overstepping their authority to stop and question citizens.

Examples that I have encountered where the opportunity to witness has presented itself and I have continued on my way:
 - cycling along Foothill Expy in the morning and passing a Latino man in a small delivery truck pulled over by an officer
 - cycling along Sunnyvale-Saratoga in the morning and passing a man on foot at a corner being questioned by an officer
 - driving along El Camino and passing a Black man at a bus stop being questioned by multiple officers

By walking by, I am tacitly agreeing to be a member of the society that hires police officers to take this particular action. I think it is too easy to assume we know what is going on there and we are OK with it. That police officer is an embodiment of myself deciding to use force.

I think we've given police too much authority to interfere in the activities of citizens that they think are weird or unusual (e.g. not having a shirt on, poking around in bushes, sitting on a sidewalk, yelling). Too broad of an authority to decide what constitutes a threat to public safety. To counter that, I feel motivated to use my privilege as a tall, white, wealthy, intelligent male to witness, document, and question police actions I encounter that don't feel quite right.

I would be thankful for a fellow citizen watching and documenting, if I were being arrested or questioned by the enforcers of the law.

Resolving this question of whether I should or shouldn't think twice, document, or even interfere, will only get better if I actually practice.

I live in Berkeley now, and frequently travel over to San Francisco, so compared to living in Sunnyvale suburbs for the last 5 years, I'm exposed to more frequent police action.

Here's a video I took on Saturday, January 12, 2019 at 4:37pm at the intersection of 5th and Bryant (37.7783, -122.3998) in San Francisco. Please contact me if you have concerns about this video being public.

0:50 - the man is injected with something by paramedic (perhaps a sedative as he does not seem to verbalize as much for the rest of the video). verbal discomfort, shock, and anger.
1:10 - lots of "I'm sorry, I'm sorry," as if in pain
7:40 - lifted onto a stretcher
8:40 - interview with bystander witness. "That should have never happened".

I was curious to follow up on this, so I went looking for some police reports. Conveniently, SF has a public database of police incident reports that is updated every few days. There is a visualization tool online, but I found it easier to use the map already provided to narrow in on the incident by location and date/time. The database entries do not have much detail, but I was able to find the Incident Numbers for the incidents most likely to be the one I saw. The time listed was about an hour off of what I observed.

To get additional info about the incident in order to label my video, I filled out a couple Request for Incident Report forms and emailed them to the SFPD. They got back to me in just a few days with the full report as written by the arresting officer.

The Incident Report (# 190029689) for the arrest of Mr. Foster is linked here:

Interesting to note the difference in narratives between the officer's report and the first-hand witness I interview in my video. The officer reports that he was kicked by Mr. Foster, whereas the witness reports that Mr. Foster was just sitting on the curb. The officer reports no complaints of pain, whereas the video clearly documents discomfort.

I feel that I still don't have enough information to pass judgement on any actions in this video. Except for the fact that I strongly do not approve of using an injection without consent.

But I feel that taking the video was worthwhile and I'll probably do it again.


Primary Production

How fast could plants in a transparent box starve themselves of CO2?

In the spring, we sprout lots of little tomato and squash plants in a plastic tray. Maybe 60 sprouts in a 2 square foot tray. Initially, we keep the tray indoors, but when the sprouts are a little bigger, we leave it outside so they get more sunlight. Sometimes we put a transparent plastic lid over them to make a little greenhouse to keep them warm on cold days. The lid makes a weak seal around the tray, and I wondered if could be starving the plants of CO2.

As a first order of magnitude check, we would expect CO2 consumption to be a modest fraction (maybe 1/3?) of the total existing mass of the plants over the course of maybe a week because the CO2 is being consumed to create plant material. It seems reasonable that sprouts should grow by 1/3rd every week. The plants in one mini-greenhouse box probably have a mass of (1g x 60) = 60g. So very roughly we would expect CO2 consumption to be somewhere around 20g per week, or about 2g per day.

Ok, lets get more precise. What volume of CO2 is consumed (and O2 released) by a certain mass of plants per day?

If we can assume the box is producing at an average rate somewhere between tundra and grassland (the sprouting tray looks like a little fell field, but it is probably growing faster than one), we can say its mean NPP is about 300 g/(m^2*yr). If our box is 0.2m^2, one day should net about 0.2g in primary production (300g * 0.2m^2 / 365days).

I'm going to use glucose as a carbohydrate representative substance for all of primary production. In photosynthesis, every 6mol of CO2 (44g/mol) yields 1mol of sugar C6H12O6 (180g/mol). So 0.2g (0.001mol) in primary production of sugar requires about 0.3g (0.006mol) of CO2.

Ok, so the plants in the box consume about 0.3g of CO2 per day. Pretty close to our initial estimate of 2g per day, as far as rough estimates go.

Now, how much CO2 is in the box?

Partial pressure of CO2 in dry air at sea level (760torr) is about 0.3torr. So 0.04%. PV=nRT, so for every 100 mol of air, 0.04 mol of CO2. Volume of air in the box is about 20L, so at 1kg/m^3 or 1g/L, we have 20g of air. Air molar mass is 29g/mol (mostly N2), so we have about 1 mol of air in the box, and maybe 0.0006mol of CO2. Which at 44g/mol is 0.026g.

Ok, so there is only about 0.03 grams of CO2 in the box.

Wow, it looks like the CO2 in the box gets used up pretty quickly. Maybe in about 1 hour.

What are the uncertainties in my estimates?
- area or volume of air in the box - probably correct within a factor of 1.5
- mass of plants in the box - probably correct within a factor of 3
- NPP assumption - desert is 90, grassland is 600 g/(m^2*yr) - so probably correct within a factor of 2 or 3.
- Assumption of glucose as a representative substance for all of primary production - the actual substance that gets made in the Calvin cycle is glyceraldehyde 3-phosphate (G3P). G3P is then transformed into sugars like glucose, which in turn are consumed to build the plant itself.

With these uncertainties, my worst case error is factor of 11 (3x1.5x2.5), so worst case bounds are from 5min to 11hours. The root sum of squares (RSS) error is a factor of 4, so the bounds are more likely from 15min to 4hours.

Make sure greenhouses get adequate ventilation!

Some supporting evidence:
“Many greenhouse growers have starved their plants for carbon dioxide in the attempt to conserve heat by limiting or eliminating air exchange in the greenhouse. Up to two full air exchanges an hour have been recommended for greenhouses to keep the plants and the equipment functioning properly.”

It's annoyingly difficult to search for anything related to greenhouses and CO2 and starving because climate skeptic articles overwhelmingly dominate the results.


Good people

“People are too big to be good” -Nick
Actions can be good, but not people or companies. But I do think it is possible to apply a utilitarian principle here - people can be mostly good if they do more good actions than bad actions. Or actions that result in more good than bad. But because it is so tricky to distinguish good outcomes from bad outcomes, espcially long term ones, the good must vastly outweigh the bad for an action conglomerate (human or corporation) to be called good.


Robust bodies

We have such beautiful robust bodies. What ideal machines. Self repairing, flexible, self sustaining, adaptable. But also a human body is a fucking kludge. It is so crazy that they do not fall apart.  But if I had to choose between either less of those robust characteristics or a more intelligible design, every day I would sacrifice more coherency in favor of a soft kludge.