Gemini* and Gopher

• Personal/Opinions

  • THAT: Hydraulic Pressure Balance

    There are some interesting or fun example circuits in the THAT manual, such as the lunar lander simulation, and euler spiral generator. But I thought it might be wiser to focus on something more pertinent to systems I use here at work. Part of what I do is maintain some hydraulic systems, so I thought it would be educational to try to simulate a hydraulic actuator system, or parts of such a system, on THAT.

    A while back I had found on the Internet a very nice — if somewhat dense — NASA report on the subject. NASA Technical Memorandum 101644, Simulated Dynamic Response of a Servovalve Controlled Hydraulic Actuator, June 1990, by NASA engineer D. A. Babcock. There is a few helpful and interesting things about this document. One is that it lays out all the differential equations involved, with a terse but complete description of the variable symbols, accompanied by a nice diagram of the basic system being modeled.

    Second, there is an entire code listing given in the Advanced Continuous Simulation Language (ACSL), which would have been used to run the simulation in that software suite. Internet information on ACSL is limited, but it is obviously a software differential analyzer system, allowing you to basically just type in your differential equations and the initial conditions, and then it will run the simulation using numerical approximation. I made an effort to see if source code for the ACSL system is available somewhere on the Internet, or to figure out if ACSL had been replaced by something more modern, but didn't have any success.

  • Entry 3 - hot runner motorcyclist frost mage chef engineer dog dad gu

    Meh. Mlep. My self-worth is tied up in this. Which is not good. But it's like ... the first time I've felt hope, and the first time I've felt _a way_ about someone in so, so many years.

    And _probably_, just like every other time, it's going to be fine. When I do talk to her it'll be warm and lovely and she'll be happy to chat with me and attentive and not signalling that she needs to get back to work at all, and she'll probably respond positively to the idea of a dog play date, and hey like even if she doesn't feel the same way and doesn't see the same endpoint ... maybe it would be nice to make a friend.

• Technology and Free Software

  • Internet/Gemini

    • tastapiwin: a server/client for mercury://

      i was reading solderpunk's page about mercury:

      see the post here

      and i was interested in it, although it's not super well-defined, i figured i could assume what i need.