Now that I've cured and tacked out the Mojave Green skin there seems to be some debate over who gets the resulting product. Isn't that always the case once the work is done?
Meanwhile the skin is drying nicely. I make sure the skin is up off the board so that air can circulate freely.
I've been exploring the model space and it's a dark, cold place. You can get lost out there. I developed a basic SIR model for disease transmission and recovery and set out to turn the knobs on the values. Recall the original model looked like the graph below. What you can see is that the blue line is very nearly at zero and the green line is approaching 1000 or the total population that I used.
The blue line being very nearly zero means there are very few members of the population left that are susceptible to the disease. The red line indicates the infectious which are the people currently suffering from infection and potential death. "Flattening the curve" is spreading out the red line in time which can be accomplished by reducing the transmission rate (social distancing.)
In my "What This Blog is About" page I mention about doing something yourself and then explaining it to someone else so you can really start to understand something. I have been asked a number of times my take on the Covid 19 business, and I have tried to stay honest and say I don't know enough about it to offer up much in the way of an opinion. I have been trying to rectify that ignorance and have made the first steps. This is my description of what I know to this point and what I have done.
I've finished my shooting Android application to my satisfaction. It has my current burn model in it and some, I repeat some, error checking in it. As usual it can be found in my Downloads Section under Mk1ShooterMod1.apk for the built Android App and Mk1ShooterMod1.aia for App Inventor file.
...Onward Through The Fog.
I decided to put together a simplified burn model to incorporate into the Android App I put together for re-loading and exterior ballistics calculations. It gives me a little better feeling for the overall veracity of the application. The powder mass function was developed with a 4th order Runge-Kutta scheme which can be found in the Open Calculators downloads section of the blog. The velocity was derived from a lumped parameter energy balance model. I used a thermochemical solver for developing some of the powder constants. I'll probably put together a thermochemical solver for here which will also be useful for detonation and explosive properties calculations which I plan to write about in the future.
During my undergraduate days I ran a shock physics lab primarily studying the welding window for explosively welding dis-similar materials. You can find a very brief article on the subject here. The gentleman I worked for at the time was considered one of the world's experts on the subject. I published a few journal articles and learned quite a bit. A few years later I was working at my career job and I got a phone call out of the blue. The caller told me that he got my name and organization from a quite obscure thing known as a world wide web search, Netscape was still fairly new and the only real browser, and he understood I knew something about explosive welding.
This is my gun... I don't suppose I need to repeat that little ditty that one picks up in Basic Training in the U.S. Army. I assume they don't use that anymore given the coed nature of the Army these days. This is the object I'm speaking of.
As I've been developing my Android application for a shooter's assistant I've also been putting the pieces I need to make it function in spreadsheet format. The recent one I have completed was looking at the exterior ballistics problem using Pejsa's Methodology which you can read about at the link. An internet search will bring up a number of uses of it. I have provided my version of it in my downloads area. The spreadsheet can be found here.
Or as they are more popularly known the Mojave Green rattlesnake. Our main residence is on the eastern front of the Sierra Nevada mountains and is classified as high desert. The high desert is full of life it just tends to be spread out more and much of it is nocturnal. One member of the local fauna is the Mojave Green rattlesnake. They can have a nasty bite as the venom is both a neurotoxin as well as a hemotoxin.
I don't see them very often but I make sure they don't stay around. If I can't transport it easily I'll put it down quickly. Children and dogs are especially at risk from a bite. Just today a woman my wife knows had an unwanted visitor. They have 5 kids and numerous dogs, so, "something has to be done!" You can guess what happened, and I brought the carcass home. Here it is showing the beautiful pattern it has and I decided I needed some more rattlesnake leather.
I've been working on a system to take with me shooting. It's essentially an external ballistics application for my Android phone that gives me bullet path calculations. It's not meant to be a whiz bang super ballistics calculator that will tell you everything for every bullet and condition. It's set up to calculate the functions I want for a limited number of cartridges, loading conditions and projectiles.
The first thing I did was develop the means to make any corrections needed for the flight path due to temperature, humidity or altitude. These can be all lumped together by calculating the air density. This is the circuit for the Assistant set-up. It's a little module (Bosch BME280) that reads temperature, atmospheric pressure, and relative humidity. I use those inputs to calculate the air density. It also accounts for any altitude corrections that might need to have been made through the direct reading of the atmospheric pressure. In fact the manufacturer likes to claim you can get an altitude within a meter or so from it. The values are read in and sent via Bluetooth to my Android app.
Over the years a lot of experimental work I did was centered around high strain rate phenomena in solids. Which, there are probably more people attending your hometown high school football game than are interested in that field.
I have always had an interest in steel, its chemistry, its properties, and also its role in human history. Thus, my interest in knifemaking which embodies the art and craft of steel as well as the science.
In testing explosives a steel witness plate is often used to give a quick qualitative look at what the explosive output may have been. Often times it's more of a convenient way to rest the test item on a more stable surface. Over the years I must have used thousands of steel plates of various sizes and deformed them, punched holes in them and generally scattered them everywhere. I think I may have spent half a year out of my life just collecting them up afterwards. Needless to say I still have a few of them lying around.
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