Development of a process for refining rape seed oil into biodiesel and high-cetane components of diesel fuel

New technology for refining vegetable oil (in particular, rapeseed oil) is proposed; a distinctive feature is the use of one transesterification reactor with a stationary bed of heterogeneous catalyst and an additional stage of hydrotreating of part of the biodiesel to obtain green diesel (high-cetane hydrocarbons) that can be used as an ameliorant for traditional diesel fuels is proposed. The material and heat balances were calculated for the proposed technology.     

Corrosion of armco iron and model Fe−Cr-Al alloys in oxygen-containing lead melts

We studied the influence of oxygen-containing (6·10⁻³ wt.% O) lead on the corrosion of Armco iron and Fe−16Cr, Fe−16Cr−1Al alloys at a temperature of 650°C under stationary conditions. The front of corrosion propagates according to a linear law and this process is periodically repeated. In each period, an oxide film based on Fe₃O₄ magnetite is formed on the surface of the metal and lead penetrates into the suboxide zone. This leads to the exfoliation the external oxide film and then the process is repeated. Under the indicated testing conditions, alloying with chromium and aluminum intensifies the process of corrosion in iron. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 33, No. 2, pp. 84–88, March–April, 1997.     

The radiation characteristics of two parallel electric dipoles with a finite screen

The 3D vector problem of diffraction of the fields of two coupled parallel electric dipoles located in parallel to an infinitely thin rectangular perfectly conducting screen is considered. On the basis of the asymptotic solution to this problem, fast algorithms and programs are developed for computation of patterns, the directive gain, and the radiation resistance as functions of the geometric parameters and electric dimensions of the radiating structure. It is shown that, when the distance between a dipole and the screen is fixed, the appropriately chosen distance between the dipoles and the appropriately chosen dimensions of the screen provide for axially symmetric patterns and the maximum maximorum directive gain.     

Lanthanide NIR luminescence for telecommunications, bioanalyses and solar energy conversion

Present-day advanced technologies heavily rely on the exciting magnetic and spectroscopic properties of lanthanide ions. In particular, their ability to generate well-characterized and intense near-infrared (NIR) luminescence is exploited in any modern fiber-optic telecommunication network. In this feature article, we first summarize the whereabouts underlying the design of highly luminescent NIR molecular edifices and materials. We then focus on describing the main trends in three applications related to this spectral range: telecommunications, biosciences, and solar energy conversion. In telecommunications, efforts concentrate presently on getting easily processable polymer-based waveguide amplifiers. Upconversion nanophosphors emitting in the visible after NIR excitation are now ubiquitous in many bioanalyses while their application to bio-imaging is still in its early stages; however, highly sensitive NIR-NIR systems start to be at hand for both in vitro and in vivo imaging, as well as dual probes combining magnetic resonance and optical imaging. Finally, both silicon-based and dye-sensitized solar cells benefit from the downconversion and upconversion capabilities of lanthanide ions to harvest UV and NIR solar light and to boost the overall quantum efficiency of these next-generation devices.     

Behavior of Vanadium Alloys in Calcium-Containing Lithium

Using the method of Auger spectroscopy, we have studied the interaction of calcium-containing lithium with vanadium alloys (V-20Ti and V-15.8Ti-9.5Cr-0.03Y) at a temperature of 700°C and holding up to 1500 h. We have established the kinetics of penetration of the liquid metal into the solid one and revealed the structural nonuniformity of propagation of the corrosion front. There exists a certain latency time during which lithium does not penetrate into vanadium alloys. In this period, a protective layer based on CaO is formed on the surface of the alloys, disperse particles of Ti _x O _y are dissolved in the under-oxide layer, and -phase is precipitated. After that, lithium penetrates into the alloy through the grains (up to 150–200 m in depth) and, later, along their boundaries. Modification of the vanadium-titanium matrix by yttrium hampers lithium penetration. Degradation of the CaO layer is attributable to a decrease in the calcium concentration in the melt.     

Use of electrodes with surface protection

GosNIIÉP. Translated from Metallurg, No. 9, p. 29, September 1990.