Codigestion of manure and organic wastes in centralized biogas plants: status and future trends

Centralized biogas plants in Denmark codigest mainly manure, together with other organic waste such as industrial organic waste, source sorted household waste, and sewage sludge. Today 22 large-scale centralized biogas plants are in operation in Denmark, and in 2001 they treated approx 1.2 million tons of manure as well as approx 300,000 of organic industrial waste. Besides the centralized biogas plants there are a large number of smaller farm-scale plants. The long-term energy plan objective is a 10-fold increase of the 1998 level of biogas production by the year 2020. This will help to achieve a target of 12-14% of the national energy consumption being provided by renewable energy by the year 2005 and 33% by the year 2030. A major part of this increase is expected to come from new centralized biogas plants. The annual potential for biogas production from biomass resources available in Denmark is estimated to be approx 30 Peta Joule (PJ). Manure comprises about 80% of this potential. Special emphasis has been paid to establishing good sanitation and pathogen reduction of the digested material, to avoid risk of spreading pathogens when applying the digested manure as fertilizer to agricultural soils.     

Electrode Processes in a Eutectic KCl–KF Melt Containing Gadolinium Oxide

The electroreduction of gadolinium from a eutectic KCl–KF melt containing 0.210–1.233 wt % Gd₂O₃ on molybdenum and glassy carbon electrodes is studied at 1008 K. The solubility of gadolinium oxide is determined. It is shown that the reduction of a gadolinium oxyfluoride complex proceeds reversibly, with a subsequent reversible chemical reaction. The gadolinium reduction on an iron electrode in a eutectic KCl–KF melt purified of unwanted oxide ion impurities yields an iron-gadolinium alloy.     

Reactions of Hydroxyazolidines with π-Donor Heterocycles. 3. Reaction of 1-Acetyl-5-hydroxypyrazolidines with Oxindoles

The reaction of oxindoles with 5-hydroxypyrazolidines on the surface of potassium fluoride-modified alumina leads to 3-(5-pyrazolidinyl)oxindoles. The structure of these products was studied.     

Simulation of exposure of light-sensitive layers: Processes involving reversible reactions

Analytic expressions relating the concentration of a light-sensitive component and the intensity of exposure UV light to the sample thickness and exposure time of light-sensitive materials with the restricted mobility of reactants were found. The processes of image formation were considered, which involve the following reversible photochemical reactions: (1) both steps are photochemical, ; (2) a thermal reaction acts as a reversible step, ; and (3) both thermal and photochemical reactions are reversible steps, .__________Translated from Khimiya Vysokikh Energii, Vol. 39, No. 3, 2005, pp. 218–222.Original Russian Text Copyright © 2005 by Zelentsov, Simdyanov.     

Temperature Dependences of HCl Activity Coefficients in Aqueous Solutions

Temperature coefficients of activity of the ionic fraction of HCl in water, calculated from tensimetric and calorimetric data, are compared. A correlation dependence is suggested for recalculating the activity coefficients of hydrochloric acid from 298 K to other temperatures.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 2, 2005, pp. 211–213.Original Russian Text Copyright © 2005 by Poltoratskii, Osovskaya, Chumanov.     

Deep oxidation of hydrocarbons and gasoline (naphtha) ejections on applied oxide catalysts

The properties of VO_x and Co-Cr-O catalysts on carriers of different nature have been studied, synthesized by impregnation and grafting. It has been demonstrated that grafting of the elements to the functional groups of the carrier produces efficient catalysts for the deep oxidation of hydrocarbons (paraffins) and gasoline ejections with a low starting temperature of the catalytic reaction.L. V. Pisarzhevskii Institute of Physical Chemistry, Ukrainian Academy of Sciences, Kiev. Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 27, No. 5, pp. 578–583, September–October, 1991. Original article submitted July 1, 1991.     

Mass spectrometric study of the pyrolysis of perfluorinated compounds of composition C6F12-C9F20, containing perfluoroisopropyl groups

The primary and final products arising from the pyrolysis of perfluoro-2,4-dimethyl-3-ethylpentane, perfluoro-3-isopropyl-4-methyl-2-pentene, perfluoro-2-methyl-3-isopropyl-2-pentene, perfluoro-2,4-dimethyl-3-heptene, and perfluoro-4-methyl-2-pentene have been studied using low-energy mass spectrometry and chromatography-mass spectrometry. Thermal decomposition of hexafluoropropene oligomers, containing perfluoroisopropyl groups attached to a double bond, occurs via loss of a radical pair to form perfluorodienes, as well as via abstraction of a hexafluoropropene molecule from the iso-C₃F₇ group. A correlation between the principal fragmentation pathway observed under electron impact and the primary process in the main thermolysis pathway was detected only in the case of perfluoro-4-methyl-2-pentene and perfluoro-2,4-dimethyl-3-heptene, which are capable of cleavage of^.CF₃ and^.C₂F₅ radicals, respectively, to give a single possible allyl radical structure.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1037–1041, May, 1990.     

Form of the dihedral angle dependence of the spin-spin coupling constant JHNNH

Cyclic hydrazides (derivatives of phtalhydrazide,pyrozolidone-3, indazolone, cyclic hydrazide camphoric acid) are studied by the NMR¹H method. The size of the dihedral HNNH angle of several model compounds (pyrozolidone-3, cyclic hydrazide norcamphoric acid) are calculated by the MINDO/3 SSF MO LCAO method. It is shown that in the hydrazides with HNNH dihedral angle 0–70° the magnitude of the HNNH spin-spin interaction constant does not exceed 1 Hz. The form of its dependence on the dihedral angle is determined.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 3, pp. 363–366, 1989.     

NMR investigation of the solubility of some lubricants in rigid and in impact modified PVC

The solubility behaviour of two paraffin-waxes and two monoglyceride-esters normally used as lubricants in PVC-formulations have been studied with wide-line NMR for rigid and for impact modified PVC. It has been shown that the investigated lubricants have limited solubility in PVC. In the impact modified product, the monoglyceride-esters are partly dissolved in the elastomer phase and partly in the PVC-phase. The paraffin-waxes have limited solubility in the elastomer and in the PVC-phases, and a considerable amount forms a separate phase.