Experimental and modeling studies of the thermal conditions and magnesium,iron, and copper content on the morphology of the aluminum silicon eutectic in hypoeutectic aluminum silicon alloys

Hypoeutectic aluminum silicon alloys without and with additions of magnesium, copper, iron, and strontium have been cast in a mold, giving directional solidification from a chill. Detailed temperature measurements have been carried out. Solidification modeling based on front tracking of the microstructure growth fronts allowed identification of the time and temperature at which the dendrite tips and the first eutectic pass the thermocouples. The undercooling, growth rate, and thermal gradients at the dendritic and eutectic growth fronts were derived. The effect of varying thermal parameters and alloy compositions on the microstructure was investigated. Compared to the binary alloy, a coarser eutectic was observed in the alloys with magnesium, iron, and/or copper. The coarsening is explained as a result of the transition from a eutectic forming at one specific temperature, to a eutectic forming over a temperature range. The former is likely to grow as a plane front, whereas the latter is likely to form an interdendritic eutectic mushy zone.     

Swelling cottony black clays as bases of buildings and structures

Peculiarities of the material composition and physicomechanical characteristics of specific swelling soils are discussed. The authors studied processes of swelling and shrinking and quantitative changes in the soils' properties as a result of these processes in laboratory and field conditions. Dnepropetrovsk Construction Engineering Institute. Translated from Osnovaniya. Fundamenty i Mekhanika Gruntov, No. 2, pp. 24–26, March–April, 1994.     

Impact of QOS requirements on video coding for ATM networks

The broadband integrated services digital networks (B-ISDN) based on asynchronous transfer mode (ATM) technology can support a wide range of applications such as voice, video, still images, and data. Compression techniques increase the effective bandwidth utilization, but the bursty and asynchronous nature of the traffic can still lead to congestion in the network, and degradation of image quality and quality of service (QOS). Some of the features to provide better coding schemes for ATM networks are layered coding, resynchronization, buffering, interleaved schemes, constrained bit rate due to buffers, encapsulation with the RTP or AAL1 for clock recovery, lapped transforms, motion compensation, and optimal bit allocation for coders based on wavelet transforms. We review various techniques forimage and video coding such as transforms, motion compensation, vector quantization, and subband coding. We outline the impact of the cell loss ratio (CLR), delay and cell delay variation (CDV) on video coding: blocking effects, loss of frame synchronization, motion vectors, and vector quantization codewords. The open problems include tuning coding parameters to the available QOS provided by the network.     

Infomativeness of multichannel Kalman filters

This article considers the informativeness of multichannel Kalman filters. Expressions are derived for determination of the amount of information obtained by additional measurements with a reserved measurement channel during processing. We prove a theorem asserting that there is an increase in the informativeness of Kalman filters when there is a failure-free researved measurement channel. Translated from Izmeritel'naya Tekhnika, No. 1, p. 9–11, January, 1996.     

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Ohne Zusammenfassung     

Experimental design in problems involving measurement of the mass of petroleum products in storage tanks

We propose a technique for optimal selection of standard pressure controllers for obtaining the best calibration characteristics for differential pressure gauges, ensuring high-quality metrological characteristics for the data acquisition systems for determination of the mass of petroleum products in storage tanks. Translated from Izmeritel'naya Tekhnika, No. 6, pp. 36–38, June, 1996.