Modelling and controller design of an isolated diesel enginepermanent magnet synchronous generator

A method to analyze the steady-state performance of a stand-alone permanent magnet synchronous generator driven by a diesel engine is presented. The proposed method is based on equivalent d-q circuits and the phasor diagram of such a generator under steady-state conditions. A fixed capacitor-thyristor controlled reactor scheme is used to regulate the generator terminal voltage by controlling the thyristor ignition angle. Furthermore the overall system dynamics are modelled in terms of state variables and control inputs. Based on a reduced order linearized model, digital optimal state and output feedback controllers are designed by minimising a quadratic performance index using the dynamic programming technique. The objective of the controller is to maintain the load voltage and frequency constant under varying load conditions. The controller's effectiveness is assessed by examining the closed-loop system response to sudden load changes     

Heat and mass transfer in abnormal metal plasticity

The authors show the decisive role and special features of heat and mass transfer in the mechanism of abnormal plasticity and in formation of thermomechanical dissipative structures under large plastic strains by the examples of computer modeling of stretching of a specimen, high-pressure torsional shear in a Bridgeman chamber, and shearing strain of a material in the form of flow of a quasiviscous liquid in a channel with local heat removal via a stationary wall.Izhevsk Mechanical Institute. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 67, Nos. 1–2, pp. 127–131, July–August, 1994.     

An automated film reader for DNA sequencing based on homomorphicdeconvolution

An automated reader for electrophoresis based DNA sequencing methods is described that provides fast and accurate sequence determination. Digitized sequencing lanes are processed with homomorphic blind deconvolution in preparation for peak detection, interlane alignment, peak refinement and base calling. Initial reads from direct blot sequencing films have error rates of about 1% at the rate of 5 nucleotides/s. Typical read lengths are 500-600 nucleotides. The described reader is a significant improvement over existing readers and could be an essential component in the sequencing efforts of the Human Genome Project     

Pressure ulcer development

VDD pacing follow-up is similar in pediatric and adult patients. Atrial and ventricular pacing parameters are stable during 2-year follow-up in children, and single-pass lead VDD pacing is recommended when the sinus node function is normal.     

Improving the chemical resistance of glass containers by thermochemical treatment with a reagent solution

A way to increase the chemical resistance of glass containers by injecting a quantity (0.2–1.0 ml) of a special reagent solution into freshly shaped items is considered.Translated from Steklo i Keramika, No. 5, pp. 8–11, 1996.     

Evaluation of hot hardness and creep of a 350 grade commercial maraging steel

The hardening response and the indentation creep of a 350 grade commercial maraging steel were evaluated using a hot hardness tester. The hardness versus temperature plot exhibited three distinct regions. Hardness response was noted between 500–800 K. The unusually high values of activation energy and stress exponent obtained during the creep experiment could be rationalized by a novel concept of introducing a back stress term in the indentation creep relation. The corrected value of the activation energy was found to be reasonably in agreement with the activation energy for diffusion of Ni in iron. Results are supplemented with microstructural observation.