john-science

FROM ubuntu:20.04

RUN apt-get update && \
    apt-get install --no-install-recommends -y python3-pip python3.8-dev && \
    apt-get install vim && \
    apt-get install git

john-science

Trustworthy Websites to Buy Coins

• US Mint - Only modern US coins and proofs and such. But absolutely trustworthy.
• VCoins - meta seller. Lots of old coins, lots of price ranges.
• ma-shops - auction site, but "certified sellers"
• Great Collections - Small, but all certified from trusted sellers
• APMEX - good for silver Peace and Morgans
• USA Coin Book - great for US coins
• NumisBids - coin auction site. Lots of variety. Hard do search. Good for filling in a hole in a set (you can set an alert).
• Heritage Auctions

john-science

A Nuclear Engineering Reading List

Good Places to Start

• whatisnuclear.com

The MIT Nuclear Engineering Ciriculum

john-science

Reading & Writing GZIP Files in Python

I have been testing various ways to read and write text files with GZIP in Python. There were a lot of uninteresting results, but there were two I thought were worth sharing.

Writing GZIP files

If you have a big list of strings to write to a file, you might be tempted to do:

f = gzip.open(out_path, 'wb')

for line in lines:

john-science

Physics - In Brief

Classical Mechanics - Super Yawn

• Newton's Laws
• Hamiltonian & Lagrangian
  • Comparison of the two equations - profoundphysics.com
  • Hamiltonian Mechanics - Wikipedia
  • Lagranian Mechanics - Wikipedia

john-science

from osgeo.osr import SpatialReference

"""
A quick script to get the Well-Known Text from a proj4 string.
"""

# build a spatial reference
sr = SpatialReference()
# enter the proj4 string
valid_code = sr.ImportFromProj4('+proj=lcc +lat_1=25 +lat_2=25 +lat_0=25.0 +lon_0=-95.0 +R=6371229.0')

john-science

Notes on "Nuclear Systems"

These are just my notes on the textbook "Nuclear Systems" Volume 1, by Todreas and Kazimi. The textbook seems to be a classic on "Thermal Hydraulic Fundamentals" of nuclear power reactors.

Chapter 1: Principal Characteristic of Power Reactors

This chapter attempts to give a friendly, high-level comparison of the different kinds of nuclear power reactors out there. It gives some reference as to their similarities and differences, and general performance and safety characteristics.

Neutron Energy Range	Energy Range Name

john-science

/**
 * The basic class syntax.
 */

public class BasicClass {

    public BasicClass() {
        // This is the constructor.
    }

john-science

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

john-science

Convert SciPy.integrate.ode.vode to Cython

This is a research task. The SciPy Vode ODE solver is 1600 lines of Fortran with 250 goto statements, so a direct translation is actually quite tedious. It would be much easier without the goto statements, or if the code was in C, C++, etcetera.

Links Roundup

• cyode
• VODE official reference
• ODE-solving iPyNB
• vode reference from rdrr.io