Bluebill.net

• 2025-01-10 - Average Cylinder Density

  Density is a straightforward concept, defined mathematically by the formula in equation (1). It represents the average mass per unit volume. When measuring density, it is typically assumed that the material is homogeneous and uniformly distributed within the volume. What if it wasn’t? I have some questions I want to examine:

• 2024-12-19 - TDR and VOD Measurements

  Detonation velocity (VOD) is a critical parameter in understanding explosive reactions. Traditional methods, such as using resistance wires, are effective but can be challenging to implement consistently in production environments like mines. This article explores how Time-domain reflectometry (TDR) can simplify the measurement of VOD, even for very short charges (e.g., 160 mm in length), and examines a novel approach using helical cable wrapping to address measurement challenges.

• 2024-08-18 - Solution Dilution

  I wanted to make some greener weed killer. I am not keen on using chemicals like Roundup. I thought I would try a greener solution. I found a random recipe on the internet:

• 2024-08-18 - Headlight Distance and Time

  In Canada, and many parts of the world, a car has high beam lights used for driving at night. They are much brighter than regular lights, and a driver should turn them off when a car is approaching. If it is not dictated by regulations, it is common courtesy to turn the high beams (or brights) off when on coming drivers are close enough.

• 2023-04-28 - Project Pivot Point to Horizontal Line

  Suppose a hole is drilled underground into the back of a drift. The hole is drilled from a pivot point at a particular height from the floor. Typically this height is a characteristic of the drill. In itself, this is relatively moderate and quite standard in underground mining. Sometimes, the drill may break down, and they need to use a different drill. Suppose further that the alternate drill has a different pivot height from the floor. How can we determine where the new pivot point of each hole would be without re-designing the pattern? To narrow the scope a little, how can we determine the new horizontal distance of the pivot point from the reference line?

• 2023-04-28 - Interest Rates - Interesting Properties

  I was working on some wage modelling in Excel and was looking at multiple increases within a given period. I wondered if the result of applying individual increases throughout the year is the same as applying the sum of the increases to the initial value (Spoiler: it is not). I work the algebra to satisfy my curiosity. It isn’t difficult, but it can be a mistake that is difficult to detect.

• 2022-07-01 - Add Timestamp to Videos

  I am involved with some experimental work, and a lot of the video footage is captured with a GoPro. They are durable and work well in the field. Unfortunately, they don’t support timestamp overlay with the date and time on the video. I used FFmpeg and a shell script to automate the process. The following script will take the video, extract the creation_time tag from the video and use that to generate the timestamp overlay.

• 2022-05-22 - Python - Loops and Exception Block Else Statements

  The try/except block has an option else clause. That else clause is executed if an exception is not raised in the block. Loops, also have an else clause. I never thought that I would actually need to use those and thought they were superfluous. Today, I used both. In the following code, I wanted to create a folder, but wanted to make sure that I didn’t create a duplicate folder (i.e. I didn’t want to write files into the same folder).

• 2022-04-22 - Windows Terminal and Cmder

  Using windows to develop can be a bit of a challenge. It doesn’t have any good tools for cross-platform python tools. On Linux, I use make and a makefile to orchestrate building and configuring virtual environments. Clone the repo and make venv and I have a functional and repeatable environment. A few months ago I discovered Cmder. I learned that it has make and most of the tools I use out of the box for windows. The only issue, it is a bit of a pain. Recently I decided to try installing windows terminal and host Cmder in that. That works really well and seems to be pretty stable and is relatively easy to install. It would be nicer if it was an automated install, but these instructions are not too bad.

• 2022-02-06 - Uncertainty Propagation in Calculations

  In science and engineering, uncertainties and errors are a fact of life. This post is a study of how uncertainties can be used in calculations. More importantly, this post explores how uncertainty is propagated to subsequent calculations. That is, given a series of calculations that build on top of one another, what happens to the uncertainty?