This is a (German) summary of basic nuclear reactor physics that has been written by me during learning for the exam of an university course.

This is a short (German) summary of the WKB approximation applied to the time invariant SchrÃ¶dinger equation, which is a method used for finding approximate solutions to linear differential equations with spatially varying coefficients.

The fast and short answer to the question which speed would be (under optimal conditions) the speed to choose for maximum car throughput on a single lane. Contrary to the often believed fact it's shown that higher speed does not correlate with higher throughput by using simple high-school math.

This post describes a simple derivation of the complex inpedance formulas well known from electronics.

Mini article about the measurement of capacitance with AVRs with a minimum of external components (in it's most extreme form none external components exploiting the gate capacitance of the micro-controllers input)

A short summary about the different meaning and interpretation of impedance, ABCD, scattering and transfer parameters in simple (linear) two port networks.

Short summary of various commonly used Gaussian integrals (1 dimensional) most of the time not shown in school textbooks.

A short summary about the basic properties of Maxwell equations, the resulting electromagnetic wave equations and commonly used gauges (Lorenz, Coulomb).

Just a short description of what I've tried (and didn't expect to work) about the usage of 3D printed parts made out of PLA in the typical desktop FDM 3D printing process, i.e. a method to build really low cost parts at home.

Something easy and simple. How to cut glass tubes and other glass parts using electrically heated hot wire.

A short summary about the operation and characteristics of thermionic emission cathodes, the current limiting factors and the most important failure modes

Mini blog article that summarizes the build of a simple 2 mA beam current electron gun from common of the shelf components gathered from the hardware store as well as some 3D printed components.

A short summary about the basic conditions in a pierce type electron gun

A mini summary on how to perform impedance matching for antennas or other devices using the NanoVNA v2 together with the NanoVNASaver and SimSmith applications based on the impedance matching of an electron deflection system

Table containing the typical atmospheric air components as well as their mean thermal speed and mean molecular mass.

Notes on the the protocol that's required to remotely control Gamma vacuum ion pumps / titan sublimation pumps via a quad pump controller and some views on the inner workings of my own library implementing the protocol

This blog post describes a really simple method to get a hint if the interior of a vacuum chamber has been contaminated with some oil without the use of expensive chemical analysis.

Pfeiffer makes great turbopumps but sometimes you want to log information or control them from an existing control system. Out of this desire I played around with the RS485 protocol used by Pfeiffer and wrote some simple unofficial tools - that's what this blog entry is about

A short summary on the workings of photodiodes, how one can interface them to simple electronics and a simple amplifier circuit

Short summary on how to build a small 6 kV power supply using an 2.1 kV microwave oven transformer, two of the accompanying capacitors and a bunch of diodes that is capable of delivering a little bit more than half a kilowatt of power

A summary on how to derive the capstan equation describing the friction of a rope on a bollard, winch or a capstan

A mini summary on how one can use Python and matplotlib to calculate and render two dimensional static electric fields generated by point charges in infinitly sized space based on Coulombs law and the superposition principle.

A summary on a procedure on how to use a galvanic process to plate copper (and other metallic surfaces) with gold using a galvanic bath

Mini recipe and hopefully descriptive summary on how to perform QR decomposition using Givens rotations which forms the basis of many linear algebra numeric applications such as least squares, GMRES, etc.

A write up of the methods used to iteratively solve arbitrary linear equations systems. This includes the definition of Krylov subspace solvers, the Lanczos and Arnoldi algorithm to build orthogonal subspaces, a summary of the steepest descent and projective methods and then as an real world realization of projective methods the conjugate gradient (CG) and generalized minimal residual (GMRES) method.

Summary on how to use operational amplifiers to build simple function generators such as square wave function generators. This approach can be used to build simple laboratory function generators as well as low frequency oscillators used for various applications.

A summary how to implement the logarithmic and exponential function using operational amplifiers - and how to use this to build simple mixers when combining with a simple summation amplifier

A short summary on how to control the Korad KA3005P power supply using Python as well as some simple samples on how to use my own control library

A simple temperature drift compensated voltage controlled current source up to 8A (10A peak) and 30V rail to rail based on OPA549 or other power operational amplifiers

This article allows you to discover how we (a group from TU Vienna and University of Vienna) brought the fascinating world of physics to life at the Wiener Forschungsfest 2022! Using a visible range laser, a bicycle wheel, and modern photodiodes, we demonstrated how to measure the speed of light in an interactive and engaging setup designed mainly for children. This hands-on experiment highlighted the incredible speed of light while also conveying the fact that light is fast but not infinitly fast and allowed visitors to influence the accuracy of the measurement themselves. This article provides a short summary about the historical context, experimental setup, and the exciting outcomes of this educational outreach project.

A mini introduction about the terms heterodyne, superheterodyne, homodyne and lock-in amplifier

A short story about how one can use autocorrelation and cross-correlation functions on discretized samples of radio frequency data and also noise to detect the frequency of a single signal, the delay of a reflected signal, the phase relation between two signals and how one can track multiple reflective targets in applications like LIDAR, sonar or radar using correlations - and how to get them robust against external influence.

In this blog post, we navigate through an unorthodox yet effective method of building models using the lmfit library, a wrapper around scipy's fitting routines. The article dives into a hands-on approach for fitting noisy data with a custom-defined Gaussian model, while suggesting that the conventional wisdom of lmfit isn't the only path to success. The tutorial initializes by installing lmfit and swiftly moves to crafting a function for the Gaussian model, which involves defining an objective function to decipher the best parameters for data fit. It guides the reader through generating synthetic noisy data, plotting it for visual aid, and conducting the fitting process. Through this procedure, a parameters are constructed and optimized to fit our model to the noisy data, followed by a presentation of the fitting report. Finally, the results are visualized, and the article concludes by discussing the advantages of this method, especially when dealing with complex or iterative models. The full code for the exercise is accessible in a GitHub GIST, allowing readers to directly engage with the material covered.

A short summary on the interaction of alkali atoms with electromagnetic radiation

Nuclear Magnetic Resonance (NMR) and Electron Paramagnetic Resonance (EPR) are pivotal techniques used to explore molecular structures and dynamics through the magnetic properties of atomic nuclei and unpaired electrons. This article provides an introducory level examination of NMR, integrating both classical and quantum mechanical descriptions. Key topics include the Zeeman effect, Bloch equations, relaxation processes, and the quantum mechanical framework involving spin operators, eigenstates, and the density matrix formalism. The discussion delves into the effects of RF driving fields, Rabi oscillations, and the incorporation of relaxation processes using the Lindblad master equation. The article concludes by demonstrating how these quantum mechanical models align with the phenomenological Bloch equations, providing a comprehensive understanding of the dynamics of spin systems under resonance conditions. While the primary focus is on NMR, the article also offers insights into EPR, broadening the perspective on magnetic resonance techniques.

Dipl.-Ing. Thomas Spielauer, Wien (webcomplains389t48957@tspi.at)

This webpage is also available via TOR at http://rh6v563nt2dnxd5h2vhhqkudmyvjaevgiv77c62xflas52d5omtkxuid.onion/