Capacity Estimation of Circulating Water-Cooling Systems Equipped with Polymeric Fills under Film Flow Conditions

Chemical and Petroleum Engineering - A calculation method is presented for determining the capacity of small-scale cooling towers equipped with polymeric fills under film flow conditions, for...     

Metallochemistry of chromium in ternary systems formed by chromium with d-metals and carbon

The results of the experimental investigation of phase equilibria at solidus temperatures of the Cr–Nb(Ta,Re)–C systems are given. They add much to the information on the Cr–dM–C systems. Certain regularities have been revealed for the phase diagram constitution, particularly detailed for those formed with high valence d-metals and applied as a basis for prediction of the Cr–Tc–C phase diagram at high temperatures yet unstudied experimentally.     

A New Method to Obtain C60 and Higher Fullerenes

In this paper we describe a new experimental method to produce fullerenes with substantial yield, based on the simple vaporisation of graphite rods in a low-frequency plasma jet. The proposed method is sustained by our earlier work on differently configured carbon structures produced by condensing carbon from vapor phase. Our goal is to provide a better-controlled, straightforward and low-cost method for generating large quantities of fullerene-containing carbon soot. A key feature of the vaporisation apparatus is that it is a combination between arc discharge and plasma jet dissociation. The vaporisation of the carbon rod is not driven by ohmic heating but rather by a discharge between the end of graphite rod and the cathode of the plasma-jet system. There are several attractive features of this procedure. First, variations in the parameters of plasma jet may be used to control systematically the size distribution of fullerene clusters. Secondly, this could be used for solid studies of larger fullerenes clusters since large clusters are only produced in low yield by the arc-discharge method. Also, we believe that there is great potential to investigate systematic doping of fullerene cluster using this technique since dopants can be easly introduced into the plasma jet prior to thermal dissociation.     

Explosive compaction of composite materials based on a powdered aluminum alloy reinforced by high-strength fibers

Compaction of a powdered aluminum alloy reinforced by high-strength metallic and ceramic fibers in a flat layer under a running explosive loading is studied. The values of the compaction pressure of the matrix material and of the failure pressure of ceramic fibers are found. The structure of the compacts obtained and the character of failure are analyzed. Lavrent’ev Institute of Hydrodynamics, Siberian Division, Russian Academy of Science, Novosibirsk 630090. Translated from Fizika Goreniya i Vzryva, Vol. 33, No. 3, pp. 152–158, May–June, 1997.     

Effect of vitamin D3 and 1,25(OH)2D3 on growth of neoplastically derived cell lines and their alkaline phosphatase activity

Inhibitory effects of 1,25(OH)2D3 and D3 on growth of four neoplastically derived cells were observed in human acute leukemia cell culture CEM-C-1 and CEM-C-7, human cervical carcinoma cell lines C-4-1 and human epithelioid carcinoma cells of cervix HeLa S3K. Concurrently, in dexamethasone-responsive cells C-4-1 and HeLa S3K there was a 1,25(OH)2D3 and D3 induced elevation of alkaline phosphatase with 1,25(OH)2D3 showing the greater effects. It is supposed that vitamins D3-induced alkaline phosphatase activity in malignant cells, which is proposed to be a possible marker of cell differentiation, can be associated with the membrane effects of these vitamins.     

Structure and properties of multicomponent eutectic alloys based on chromium and titanium carbide

We have investigated alloys in the Cr-Mo-Ti-C, Cr-Re-Ti-C, and Cr-Mo-Re-Ti-C systems in the eutectic <Cr>+<TiC> crystallization region. We found a four component quasibinary eutectic <Cr, Mo>+<TiC> with 4–8 at. % molybdenum content with melting point 1630°C. Additions of 3–11 at. % Mo or 5–20 at. % Re to the base eutectic alloy Cr₇₉Ti₁₂C₉ doubles the Vickers hardness at 1000°C (to approximately 2000 MPa), and simultaneous introduction of molybdenum and rhenium (the alloy Cr₅₁Mo₈Re₂₀Ti₁₂C₉) raises the hardness to 3000–3500 MPa. Ukrainian Materials Science Institute, National Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 1–2, pp. 15–23, January–February, 1997.     

Microstructure and Physical–Mechanical Properties of (TiAlSiY)N Nanostructured Coatings Under Different Energy Conditions

Nanostructured multicomponent (TiAlSiY)N coatings were fabricated by the cathodic-arc physical vapor deposition (CA-PVD). In this study, a bias potential applied to the substrate was ??200 and ??500 V, and changes in structure and properties of coatings were investigated. Samples had a single-phase state with a face-centered cubic (FCC) lattice. Small crystallites of about 7.5 nm and texture with [110] axis were observed at ??500 V. However, lower bias potential resulted in the formation of crystallites of about 41.6 nm with [111] preferred orientation. Moreover, coatings were characterized by superhard state and demonstrated low wear, high abrasion and crack resistance. The testing of the polycrystalline cubic boron nitride (PCBN) cutting inserts covered with (TiAlSiY)N revealed an increase in the tool life coefficient during cutting by 1.66 times in comparison with the base tool material. Therefore, (TiAlSiY)N coating is a perspective material for application as a protective layer in cutting tools.