Waste products from the butane-butylene fraction as raw material for the production of methyl-tert-butyl ether

Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 8, pp. 7–8, August, 1990.     

Unfired dolomite refractories with increased hydration resistance

Conclusions The use of dolomite burnt in grain form for the manufacture of unfired goods with a tar bond makes it possible to obtain refractories with a high hydration resistance and with high physicomechanicai properties. Coal tar with a 65–70% pitch content should be used as a bonding agent.Sintered grain dolomite should be added to the batch without being ground, preferably in combination with finely ground metallurgical magnesite or magnesite-dolomite clinker.     

Energy conversion at liquid/liquid interfaces: artificial photosynthetic systems

This chapter focuses on multielectron reactions in organized assemblies of molecules at the liquid/liquid interface. We describe the thermodynamic and kinetic parameters of such reactions, including the structure of the reaction centers, charge movement along the electron transfer pathways, and the role of electric double layers in artificial photosynthesis. Some examples of artificial photosynthesis at the oil/water interface are considered, including water photooxidation to the molecular oxygen, oxygen photoreduction, photosynthesis of amphiphilic compounds and proton evolution by photochemical processes.     

Carbohydrate molecular weight profiling, sequence, linkage, and branching data: ES-MS and CID

This section summarizes several strategies for a more complete understanding of carbohydrate structure with a focus on glycolipids and glycoprotein glycans. The techniques include periodate oxidation to impart greater molecular specificity to isomeric glycans, methylation to improve sensitivity and the information content within CID spectra, electrospray for "soft" and efficient ionization, and CID to obtain structural detail. The lipophilicity of the products following derivatization contributes to product cleanup by solvent extraction and enhances sensitivity during ES. When combined with CID information, this yields sequence, linkage, and branching information. Oxidation and reduction preceding methylation augments CID analysis with an altered structure that can be profiled at the same sensitivity. Within the context of established motifs, these contrasting profiles corroborate glycan structure and specifically identify isobaric elements transparent in the initial profile. An earlier report indicating ring-opening fragments were essentially absent in low-energy collisions of methylated and natriated oligosaccharides contrasts our observations. However, as this report used a methylated oligomer containing an internal N-acetylhexose as an illustration, the conclusion is plausible (cf., Figure 9). The poor ionization efficiency of FAB and the high matrix background limit the dynamic range in the CID spectrum and, thereby, the ability to unambiguously identify weaker peaks. It would be expected that high-energy CID affords a broader range of fragment types, including ring-opening fragments. In terms of a structural methodology, this is ambivalent since the increase in fragmentation pathways also applies to small molecule eliminations which are usually less informative. In ES-CID-MS, the carbohydrate chemist has a powerful new tool in hand for structural elucidations that can be conducted at the low-picomole level. Parallel developments can be expected to continue for other ionization methods, in particular matrix-assisted desorption/ionization on linear and reflectron time of flight mass spectrometers, and improvement in the performance and sensitivity of high-resolution mass analyzers through the use of focal plane detectors and more sophisticated hardware and software for Fourier transform ion cyclotron resonance mass measurements. These have, as yet, only begun to be applied to carbohydrate structural analysis but should add still more versatility to experimental design in the future.     

Making of the clinicophysiological diagnosis within the system of medical flight certification

Adaptation responses were evaluated in flying personnel during medical examination with the use of simulators of the main dynamic factors of flight. Utility of assessing the adaptive reactions of the cardiovascular system by their physiological "cost" has been demonstrated. Parameters of the normal cardiovascular response to moderate hypoxia in altitude chamber have been established. On the basis of accumulated data, more sensitive and informative criteria for assessment of the functional state of the human organism are proposed for clinicophysiological diagnostics within the system of medical certification of flying personnel.     

A preclinical study of the effect of the animal polysaccharide chonsurid on reparative osteogenesis of the jaws

Experimental studies making use of morphological and x-ray methods demonstrated that in comparison with control (filling of mandibular bone defects with blood clots) chonsuride, an animal polysaccharide, promoted earlier filling of postoperative bone cavities with connective tissue replacement of this tissue with coarse-fiber bone tissue. Secondary restructuring and mineralization of bone regenerate were enhanced as well.     

Modification of electrical and optical properties of ZnO films under ultraviolet irradiation

The effect of ultraviolet radiation of polycrystalline zinc oxide films (with a thickness of 200 nm) on their resistivity, transparency, and luminescence in the visible and violet spectral regions is studied. It is shown that, under irradiation of the films in air and vacuum, the conductivity, transmittance, and edge luminescence intensity increase with characteristic times of about 100 min. It is established that the corresponding processes controlled by desorption of oxygen atoms and molecules from the surface of nanocrytals in the ZnO films are reversible.     

Effect of external force fields on the domain structure of equiatomic CuAu alloy

Peculiarities of the ordered-structure formation in the equiatomic CuAu alloy, which are caused by changes in the sample dimensions and by an applied external force field, have been studied. The rate of the microstructure transformation in the ordered alloy has been found to increase with increasing thickness of the sample. It has been shown that tensile stresses applied during heat treatment can affect the growth direction of c domains and, thus, makes it possible to avoid the low-temperature cracking of the material.