The speech clinician: ''your forgotten ally''

The regularities of development of postresuscitation cardiodepression were studied in experiments on outbred male rats resuscitated after 4-min clinical death from acute blood loss. The studies were carried out for the whole organism, isolated isovolumetrically contracting heart, and for the isolated papillary muscle. As a result of acute critical blood loss, the functional reserve of the myocardium dropped and fatigue rapidly developed, progressing to asystole and fibrillation during the maximal exercise. Cardiodepression was expressed most of all during the first day, particularly during the first hours after resuscitation. Later the contractility gradually normalized, and 3 months after resuscitation it did not reliably differ from the control. The disorders involved the relaxation processes most of all.     

Analysis and comparison of real-time sine-wave generation for PWMcircuits

Four methods for hardware and software generation in real time of sine waves suitable for PWM circuits are presented. The sine waves are derived from a truncated modified cosine Taylor series, wt(π-wt) function, a digitally filtered trapezoid, and a second-order differential equation. Triplen injection is incorporated by the addition of a defined magnitude triangular waveform of three times the fundamental frequency. Each sine wave generating technique is implemented, as applicable, in a programmable logic cell array and/or in microprocessor-based software. In each case, the output spectra and total harmonic distortion are compared with computer-simulated results     

Large scale transmission network planning using optimization andheuristic techniques

Pursuing optimal solutions for large scale transmission network planning problems is a formidable task due to their combinatorial nature and also due to the nonconvexities involved. Successful approaches using hierarchical Benders decomposition incur in a high computational cost mainly due to the need to solve a large integer program (the investment sub-problem) for every Benders iteration. In this work the authors propose to use heuristics within the decomposition framework, therefore avoiding to solve to optimality each integer sub-problem. The global computational effort is substantially reduced, and allows coping with large problems that would be intractable using classical combinatorial techniques. Case studies with the 6 bus Garver test system and a reduced Southeastern Brazilian power network are presented and discussed     

The effect of error control coding in multichannel FSK coherentlightwave communication systems influenced by laser phase noise

It has been shown that coherent optical fiber receivers with a two-filter structure (TFS) consisting of a wide-band IF filter and a narrow-band postdetection filter are less susceptible to the influence of phase noise. However, the expanded IF bandwidth required to achieve optimum sensitivity performance is large, particularly in multichannel FSK systems. Forward error control coding can relax the laser linewidth requirement and improve receiver sensitivity. In this paper a multichannel asynchronous FSK scheme equipped with (31, k) Reed-Solomon codes is used to verify the coding benefit. A systematic error probability analysis is developed and a stable and accurate performance evaluation procedure is provided. The sensitivity penalties due to the combined phase noise and interchannel crosstalk for both coded and uncoded systems are calculated for comparison. The results show that the performance reduction due to phase noise can be largely alleviated by choosing a proper code rate and an optimum value of the expanded IF bandwidth     

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.