Efficient Physicochemical Treatment Technology for Nepheline Concentrates

The processes of physicochemical treatment of nepheline concentrates are studied theoretically and experimentally, and the optimal conditions are determined for the integrated fluoride–ammonium recovery of different useful components. The enabling innovative technology is proposed for the production of amorphous silica, alumina, red iron oxide, calcium fluoride and other marketable products.

     

Editorial: Security and Privacy Protection for Mobile Applications and Platforms

Mobile Networks and Applications -     

Computation offloading balance in small cell networks with mobile edge computing

Wireless Networks - As a promising way to offset the low computation capacity of user equipments (UEs), mobile edge computing (MEC) has attracted great attention of academy and industrial recently....     

Programmable CMOS CNN Cell Based on Floating-gate Inverter Unit

At present, the Cellular Neural Network (CNN) is a potential parallel structure able to perform image processing tasks in real-time when is effectively implemented in CMOS technology. The CNN silicon integration success is due mainly to the local connectivity of processing cells. In this work, an alternative design based on floating-gate MOS inverters is presented, which uses unipolar signals for solving binary tasks. The approach brings a fast response in a reduced silicon area, as shown through electrical simulations. A prototype cell in CMOS technology (AMI, 1.2 micron) was fabricated and tested for eight image processing tasks.

Fatigue properties of a yarn based on an aromatic polyamide

Conclusions The frequency and temperature dependences of PABI yarn lifetime under repeated extension deformations have been investigated.A nonlinear temperature dependence of lifetime has been detected for PABI yarn.Translated from Khimicheskie Volokna, No. 1, p. 49, January–February, 1987.     

Fundamental principles for choosing steels on the basis of results of wear tests

The development of scientific foundations for the creation of new high-strength steels with high wear resistance and their application is a very important problem of modern engineering. The difficulties of its solution are connected with the absence of methodological foundations for a reliable estimation of the wear resistance. The fundamental scientific principles for control over this characteristic with allowance for the structural changes and the corresponding changes in the mechanical properties of steels have not been developed. The place of this characteristic and its relationship with the structure in the theory of fracture of materials under various loads has not been determined yet. At the same time, the wear resistance is a parameter that can characterize the operational reliability of steels under various conditions. However, the methods for determining the wear resistance should be substantiated experimentally and theoretically. The aim of the present work consisted in choosing steels for parts operating under the conditions of composite loads and abrasive wear. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 28–30, February, 1998.     

Metal silicide/poly-Si Schottky diodes for uncooled microbolometers

Nickel silicide Schottky diodes formed on polycrystalline Si 〈P〉 films are proposed as temperature sensors of monolithic uncooled microbolometer infrared focal plane arrays. The structure and composition of nickel silicide/polycrystalline silicon films synthesized in a low-temperature process are examined by means of transmission electron microscopy. The Ni silicide is identified as a multi-phase compound composed of 20% to 40% of Ni₃Si, 30% to 60% of Ni₂Si, and 10% to 30% of NiSi with probable minor content of NiSi₂ at the silicide/poly-Si interface. Rectification ratios of the Schottky diodes vary from about 100 to about 20 for the temperature increasing from 22℃ to 70℃; they exceed 1,000 at 80 K. A barrier of around 0.95 eV is found to control the photovoltage spectra at room temperature. A set of barriers is observed in photo-electromotive force spectra at 80 K and attributed to the Ni silicide/poly-Si interface. Absolute values of temperature coefficients of voltage and current are found to vary from 0.3%℃ to 0.6%/℃ for forward bias and around 2.5%/℃ for reverse bias of the diodes.     

Autogenous healing of engineered cementitious composites at early age

Autogenous healing of early ages (3 days) ECC damaged by tensile preloading was investigated after exposure to different conditioning regimes: water/air cycles, water/high temperature air cycles, 90%RH/air cycles, and submersion in water. Resonant frequency measurements and uniaxial tensile tests were used to assess the rate and extent of self-healing. The test results show that ECC, tailored for high tensile ductility up to several percent and with self-controlled crack width below 60 μm, experiences autogenous healing under environmental exposures in the presence of water. However, the recovery for these early age specimens is not as efficient as the recovery for more mature specimen, for the same amount of pre-damage and exposure to the same environment. Even so, the self-healing for these early age specimens demonstrates high robustness when the preloading strain is limited to 0.3%. This conclusion is supported by the evidence of resonant frequency and stiffness recovery of the healed ECC materials.