perseverate

Perseverate - "repeat or prolong an action, thought, or utterance after the stimulus that prompted it has ceased"

It helped me - a lot - to realize I was doing this - here's my journey.

I have to actively work against perseverating.  A mentor told me, "Why do you let things live rent free in your head?" I realized that what I considered "idle time" for my mind was actually valuable and I shouldn't waste it.

I spent entire bike rides to/from work - or woke up in the middle of the night - replaying conversations - redoing arguments.  It made me irritable and sad and defensive. I realized life is too short - of all the possible things I could be doing this was not a priority!

It wasn't an immediate change and the work is ongoing but I've tried to build habits to manage it. Initially I would distract myself when I realized I was starting, I would pinch myself.  Gradually I was able to very deliberately try to start a different train of thought.

I try to think about a puzzle or riddle or mathematical challenge.  I also preempt by listening to audio books, or at night reading about an interesting topic (thanks Wikipedia/astronomy!)

instagram  post

twitter thread

homebrew cider second attempt: backsweetening

NB this didn't work that well b/c I should have also added potassium metabisulfite.

Tue Feb 22, 2022

 5 gallons cider, Carlson Orchard - pasteurized but no additives (especially no potassium sorbate)

1 yeast packet (1 oz.) Red Star Premiere Blanc (formerly champagne yeast)

Sterilized equipment (carboy, funnel, airlock).  Poured cider into carboy, added yeast, put on airlock.

Friday Mar 18, 2022 9:40 PM

Added 2.5 tsp of potassium sorbate.  Mixed carboy thoroughly

*** should have added postassium metabisulfite ***. Sorbate stops yeast from dividing, does not stop them from fermenting.

backsweetening reference

backsweetening calculation

1st batch of hard cider came out very dry - assume it is between 0 and 9 g/L sugar based on reference above.  Assume it is 0 g/L, then if I get it to 9 g/L, it is at the boundary between dry and medium and will be sweeter than previously, but definitely not too sweet.  If it starts at 9 g/L

target 9 g/L = 2.1 g / cup

initial volume:  5 gallons * 16 cups/per gallon = 80 cups

x = # cups of apple cider to add

sugar amount:  (24 g/cup) * (x cups)

total volume:  x + 80 cups initial volume

sugar concentration (g/cup) s = 24*x / (x + 80)

target concentration:  2.1 g/ cup

2.1 = 24x/(x+80)

2.1*(x+80) = 24x

2.1*x + 168 = 24x

21.9*x = 168

x = 7.67 cups

What happens if initial amount of sugar is not zero?

residual sugar amount:  80 cups * (y g/cup residual sugar)

sugar concentration is:  (24*x + 80*y) / (x + 80)

assume x=8 from above, then sugar concentration is:

s = (192 + 80*y) / 88 = 2.2 + 0.91*y

if y is 2.1 g/cup then sugar concentration is:

s = 2.2 + 0.91*2.1 = 2.2 + 1.8 = 4 g/cup

This is still in the "medium" cider range, closer to the dry end of the scale.

quick notes on using a corny keg

link to website with description of parts of keg

 out port:

• is for liquid to come out 
• labeled out on keg
• use long dip tube that reaches to bottom of keg with it

in port

• is for gas to go into the keg
• labeled "in" on keg
• the keg post has notches on the base to identify it (notches are cut through the edge of the hexagonal wrench mating surfaces)
• use short dip tube with it

lid

• to seat the lid make sure to use high pressure - 30 psi
• could try reversing the direction of the lid

Would be possible to generate artificial gravitational waves that could be detected with the current detectors (LIGO, VIRGO)?

There has been a stunning revolution in astronomy over the past ~6 years with the detection of gravitational waves by the LIGO and VIRGO consortium.  Now that we are detecting "naturally" made gravitational waves, I've been wondering could we generate them artificially - and detect them?

Would be possible to generate artificial gravitational waves that could be detected with the current detectors (LIGO, VIRGO)?  Short version - seems like no.  Sources that have currently been detected are mergers of black holes and neutron stars that are 10's to 100's of megaparsecs away, so first I consider reducing the mass and having the source be closer - and this still requires incredibly large masses moving very fast (now in close dangerously close proximity!)

I also tried a quick idea about using motion of electrons within atoms to generate gravitational waves, but electron motion is not that much faster, and the mass of the electrons is much too small.  Motion of atoms within molecules would not achieve the required speeds and thus would require even more mass.

Understanding MOSFETs for use in a thermostat

Basic MOSFET background and operation

A MOSFET is basically a switch that can be controlled electronically - it's an acronym for Metal-Oxide-Semiconductor Field-Effect Transistor.  Here is the electronic diagram of a MOSFET, note it has 3 leads labelled D, G, S:

Betting on the 2020 US presidential election *after* the election

A couple weeks after the 2020 US presidential election was held, Nate Silver tweeted several times about the irrationality of betting markets (for example PredictIt), since they still had a 10% chance of Trump wining various states.

Other versions of this tweet talked about "free money" and "money left on the table".  I decided to try it out for myself discovering along the way that Nate failed to take into account transaction costs and market limits/barriers that contribute substantially to maker distortion.  In other words, it's not solely as Nate says irrational people, but also other well know sources of market inefficiencies..

using LaTex in blogger

 Bit of a meta post here - how I use LaTex formatting for math / equations in blogger.  Starting with this Stack Exchange TEX question/answer, I copied the provided code to load the MathJax library and then followed these blogger/google instructions in the section "change your blog with HTML or css", in the html section - edited the blog template, added the code copied from above into the <head> section.  Seems to be working now:

$$a^2 + b^2 = c^2$$

$$y(x) = sin(\omega x)$$

$$c^2 = a^2 + b^2 - 2ab \cos(c)$$