Active Monitoring of Thermal Insulation Protection Status of Pipelines

Refractories and Industrial Ceramics - The article discusses the temperature regimes of transit pipelines for steam and hot water movement. A new device for thermal insulation of high-temperature...     

Influence of the doping level and the temperature on electron mobility in then channel of an mos field-effect transistor

Based on results of measurement and processing of volt-ampere characteristics as well as linetic modeling of electron transfer by the Monte Carlo method, the influence of the doping level and the temperature on electron mobility in the n channel of a silicon MOS field-effect transistor operating in a linear regime is investigated. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 71, No. 1, pp. 116–119, January–February, 1998.     

Textures in nanostructured metals processed by severe plastic deformation

This work demonstrates and analyzes the experimental results of the crystallographic texture formation processes in pure metals with a different type of crystal lattice, which were subjected to severe plastic deformation (SPD) applying various techniques such as high pressure torsion (HPT) and equal-channel angular pressing (ECAP). This article is based on a presentation made in “ICOTOM-13: Textures of Materials” held at Seoul National University, Seoul, Korea, August 26–30, 2002, organized by The Korean Institute of Metals and Materials BK21 Division of Materials Education and Research (Seoul National University) and Texture Control Laboratory (Seoul National University).     

Microstructures and properties of ultrafine-grained pure titanium processed by equal-channel angular pressing and cold deformation

Equal-channel angular pressing (ECAP) has been used to refine the grain size of commercially pure (CP) titanium as well as other metals and alloys. CP-Ti is usually processed at about 400 degrees C because it lacks sufficient ductility at lower temperature. The warm processing temperature limits the ability of the ECAP technique to improve the strength of CP-Ti. We have employed cold deformation following warm ECAP to further improve the strength of CP-Ti. Ti billets were first processed for eight passes via ECAP route Bc, with a clockwise rotation of 90 degrees between adjacent passes. The grain size obtained by ECAP alone is about 260 nm. The billets were further processed by cold deformation (cold rolling) to increase the crystalline defects such as dislocations. The strength of pure Ti was improved from 380 to around 1000 MPa by the two-step process. This article reports the microstructures, microhardness, tensile properties, and thermal stability of these Ti billets processed by a combination of ECAP and cold deformation.     

Features of secondary immune response and status of nonspecific resistance of the rat, fed rations with mare's milk, rich in essential fatty acids

The influence of essential fatty acids of mare's milk fat on the immunocompetent system and nonspecific resistance was investigated after 6 and 8 weeks of feeding. Rats were fed with isocaloric purified diets containing 15% of test fat (combination of lard and sunflower oil--in control) which provide the ratio of omega-6/omega-3 fatty acids equal to 0.76. After 6 weeks of feeding an increase of immune responsiveness and nonspecific resistance in the group fed with the diet with mare's milk fat on the 6th day a single immunization of the animals with 5% sheep erythrocyte suspension was noted but that increase of secondary immune responsiveness was not noted after 8 weeks of feeding, an increase of nonspecific resistance is kept.     

Experimental setup for determining the thermal conductivity of semiconductor solar cells

An improved experimental setup for determining the thermal conductivity of semiconductor solar cells is described. The setup is reliable in operation, and the method of determining the thermal conductivity of the material is quite simple, which allows for the determination of the thermal conductivity with an error ≤3%.     

In vitro corrosion and cytotoxicity on microcrystalline, nanocrystalline and amorphous NiTi alloy fabricated by high pressure torsion

Bulk nanocrystalline and amorphous Ni50.2Ti49.8 alloy samples were successfully prepared from commercial microcrystalline Ni50.2Ti49.8 alloy discs by high pressure torsion (HPT) technique. Then their corrosion resistance, surface wettability and cytotoxicity were further studied from the viewpoint of biomaterials. In both Hank's solution and artificial saliva, bulk nanocrystalline and amorphous Ni50.2Ti49.8 alloys showed significantly higher pitting corrosion potentials than that of microcrystalline Ni50.2Ti49.8 alloy. Meanwhile, the amount of Ni ion release after immersion in Hank's solution was minor, far below the threatening threshold of daily diet. Murine fibroblast and osteoblast cell lines were indirectly co-cultured with experimental sample extracts, indicating no cytotoxicity. Amongst all samples, the nanocrystalline Ni50.2Ti49.8 shows promising as best biomaterial candidate for its good combination of mechanical property, corrosion resistance and cytocompatibility.