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171.
Eduardo Buenrostro-Gonzalez Marcela Espinosa-Pe a Simon Ivar Andersen Carlos Lira-Galeana 《Petroleum Science and Technology》2001,19(3):299-316
Asphaltenes and resins have been separated from four mexican oils suffering from the deposition of asphaltenic material during recovery operations. A SARA separation of the oils was performed and the resins and asphaltenes further analyzed. Characterization methods employed were FTIR, elemental composition both of CHNSO, and trace metals and molecular weight determination using size exclusion chromatography. NMR techniques were applied to two asphaltene samples. The overall scope of the work was to get a better understanding of the nature of the asphaltene stability at a molecular level in these problematic oils. Separation of resin in two fractions indicates that there is no long alkyl chains in these as given by FTIR, which may be the cause of the lack of stability along with the large difference in bubble point and reservoir pressure. 相似文献
172.
Tomas Isaksson Geir Tgersen Arve Iversen Kjell Ivar Hildrum 《Journal of the science of food and agriculture》1995,69(1):95-100
Near infrared (NIR) diffuse spectroscopy was used to determine the fat, moisture and protein contents in whole and ground farmed atlantic salmon fillets. A remote fibre-optic probe was used for NIR measurements on 50 whole salmon fillets. The constituent ranges were: 91-205 g kg?1 fat, 599-709g kg?1 moisture and 186-209 g kg?1 protein. Principal component regression resulted in the following prediction errors for ground salmon fillets, expressed as root mean square error of cross validation: 6.6 g kg-1 fat, 3.8 g kg?1 moisture and 2.0 g kg?1 protein. The corresponding prediction errors for non-destructive measurements on whole salmon fillets were 10.8 g kg?1 fat, 8.5 g kg?1 moisture and 3.7 g kg?1 protein. Regression models using the 760-1100 m range gave lower prediction errors than models using the 1100-2500 mm or 760-2500 nm ranges. The results show that fibre-optic probe NIR instruments are suited to determine fat and moisture in whole salmon fillets non-destructively. 相似文献
173.
Truls Norby Peter Hugh Middleton Eddy W. Hansen Ivar Dahl Arnfinn G. Andersen 《化学工程与技术》1995,18(2):139-147
A solid state electrochemical reactor is described in which reactants can be oxidised at high temperatures over an anode/catalyst using co-fed oxygen gas as well as electrochemically supplied oxygen. The setup permits injection of isotopic pulses in the reactant streams. The composition and isotopic distribution in the products are recorded with a quadrupole mass spectrometer. The use of the system is exemplified by oxidation of methane over a Au + SrFeO3?δ//YSZ anode at 800–850°C. Pulses of 18O2 in the stream of co-fed O2 were used to study the reactivity and products of gaseous oxygen as distinguished from the electrochemically supplied oxygen. The results indicate that the anode used supports oxygen pumping, but is only moderately active for methane oxidation. The products are mainly CO and CO2. The content of 18O in the products is low, indicating that methane oxidation takes place by 16O-rich lattice oxygen. In comparison, a reference Au//YSZ electrode was found to be a slower anode for oxygen pumping, but a better catalyst for the reaction between CH4 and gaseous O2, seemingly involving adsorbed oxygen. 相似文献
174.
Lovaas O. Ivar; Koegel Robert L.; Schreibman Laura 《Canadian Metallurgical Quarterly》1979,86(6):1236
Reviews a series of investigations that suggest that autistic children show "stimulus overselectivity," a response to only a limited number of cues in their environment, and discusses how such overselectivity may relate to several of the behavioral deficits in autism. These include failure to develop normal language or social behavior, failure to generalize newly acquired behavior to new stimulus situations, failure to learn from traditional teaching techniques that use prompts, and a general difficulty in learning new behaviors. Several studies that suggest possible remedial procedures are discussed, and the concept of stimulus overselectivity is related to the literature on attentional or response deficits in adult schizophrenia, mental retardation, learning disabilities, and autism. (2? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
175.
Politically speaking, the most striking feature of the planned reorganization of Swedish broadcasting is a further decentralization and localization of production. 相似文献
176.
177.
Kati Klein Arthur Kivi Niina Dulova Ivar Zekker Erik Mölder Toomas Tenno Marina Trapido Taavo Tenno 《Clean Technologies and Environmental Policy》2017,19(2):541-551
This pilot study describes a three-stage continuous process for treating landfill leachate containing significant concentrations of recalcitrant organic substances. The proposed technological scheme consisted of an activated sludge pre-treatment combined with a Fenton-like process enhanced by continuous sludge reuse and followed by an activated sludge post-oxidation. Biological pre-treatment removed >99, 86, >99, 83 and 86 % of BOD7, COD, NH4 +–N, phenols and the sum of lignin and tannins, respectively. Operational conditions in the ferric sludge-catalysed Fenton-like process stage were carefully adjusted in order to maintain the efficacy and practicability of combined treatment scheme. Although the application of ferric sludge as a catalyst in the Fenton-like oxidation reduced COD removal efficiency by 32 % as compared to the conventional Fenton process, lower process efficiency was compensated by reducing the water exchange ratio to 50 % without increasing the consumption of reagents. Moreover, an intermittent addition (added to every second treatment cycle) of fresh ferrous iron catalyst at a H2O2/Fe2+ w/w ratio of 20/1 increased the BOD7/COD ratio from 0.04 to 0.32 and resulted in 60 % COD removal. A cyclic addition (added to every treatment cycle) of the same amount of catalyst increased the BOD7/COD ratio from 0.09 to 0.32, and a 10 % higher COD removal efficiency as compared to intermittent catalyst addition was achieved. Finally, biological post-treatment of the leachate resulted in more than 95 % removal of each measured parameter. Overall, the combined technological scheme with continuous ferric sludge reuse in the Fenton-like stage proved promising alternative for landfill leachate treatment. 相似文献
178.