Studies of n-octane transformations on zeolites under hydrocracking conditions in a two-reactor flow-circulation system

Transformations of n-octane under hydrocracking conditions in a two-reactor flow-circulation system have been studied. It has been established that at high hydro-dehydrogenation activity of zeolite catalysts the reaction mechanism involves an initial step of paraffin dehydrogenation on a metal component and subsequent steps of cracking, isomerization and disproportionation of intermediate olefins on an acid component. Sodium content in zeolite determines the paraffin hydrocracking selectivity.

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Triterpenoids from the leaves ofBetula lanata

From the unsaponifiable fraction of an ethereal extract of the leaves ofBetula lanata, in addition to 3-epiocotillol (I) we have isolated a new triterpene, 20(S), 24(R)-epoxydammarane-3,11,25-triol (V) and also derivatives of it — the monoacetates at C-3 (II) and C-11 (III), and the monoketone at C-3 (IV). The structures of compounds (I-V) have been established on the basis of the results of physicochemical investigations.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center of the Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 513–516, July–August, 1980.     

Beta-electric elements made of amorphous silicon

We consider the main characteristics of a cell converting the energy of β radiation from a tritium source into electric energy. For such a cell, we propose that the design and technology used for preparing a-Si:H-based solar cell panels be employed.     

Investigation of the Pour Point Depression Ability of Polyalkyl Acrylate Additives After Sonication

Russian Physics Journal - Effect of ultrasonic treatment on the molecular parameters of polymeric additives based on polyalkyl acrylate is investigated. The viscosity, temperature, and energy...     

Investigation of diffuser characteristics in an aerodynamic shock tube

An investigation has been made in an aerodynamic shock tube, with M=8, of the diffuser starting with variable Reynolds numbers, and its throttle characteristics have been recorded. The results obtained enable conclusions to be made regarding the possibility of investigating diffusers in such types of tubes. In [1] the possibility of, in principle, determining the throat starting of a diffuser in an aerodynamic shock tube, and the time to establish flow in the diffuser channel, which was 300 sec, was measured. This paper is devoted to the further investigation of diffuser operation with variable Reynolds numbers, and to determining the throttle characteristics, in particular, the total pressure reduction coefficient.Moscow. Translated from Izvestiya Akademii Nauk SSSR, mekhanika Zhidkosti i Gaza, No. 1, pp. 156–161, January–February, 1972.     

Synthesis of 2,2’-(ethane-l,l-diyl)bis(3,5,6,7,8-pentahydroxy-l,4-naphthoquinone), a metabolite of the sea urchins Spatangus purpureus,Strongylocentrotus intermedius,and S. droebachiensis

A key step in the synthesis of 2,2’-(alkane-l,l-diyl)bis(3,5,6,7,8-pentahydroxy-l,4-naphthoquinones) is an acid-catalyzed condensation of 2-hydroxynaphthazarins, the products of the retro aldol reaction of 2-hydroxy-3-(l-hydroxyalkyl)naphthazarins, with the corresponding aldehydes. This method is applicable, in particular, for the preparation of compound with the ethane-1,1-diyl bridge — a metabolite produced by the sea urchins Spatangus purpureus, Strongylocentrotus intermedius, and S. droebachiensis.