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991.
Perovskite-type oxide monolithic catalysts for combustion of chlorinated hydrocarbons 总被引:3,自引:0,他引:3
Ralf Schneider Dieter Kiessling Gerhard Wendt Wolfgang Burckhardt Georg Winterstein 《Catalysis Today》1999,47(1-4):429-435
The catalytic activity of perovskite-coated and perovskite-extruded monolithic catalysts was studied in the total oxidation of several aliphatic chlorinated hydrocarbons. At low reaction temperatures a reversible catalyst deactivation takes place. The complete decomposition of the chlorinated hydrocarbons without formation of by-products depends on the reaction conditions, the kind of chlorinated hydrocarbon and the monolith preparation. 相似文献
992.
993.
Non‐thermal plasma for emission protection: State of the art and future prospects The reduction of emissions from exhaust gas streams is becoming more and more important issue in the highly industrialised society. Due to its impact on air, soil and water exhaust pollutions affect the whole environment and thus human health. Therefore environmental norms and standards are constantly increased by national and international authorities. The possibilities of air‐pollution control by means of non‐thermal plasmas are well known. Plasmas contain active and highly reactive species, in particular electrons, ions, atoms, molecules, and radicals, which can decompose of filter pollutant molecules and particulate matter. This contribution intends to summarize the possibilities or pollution control by means of non‐thermal plasmas. Commercially available plasma based and plasma assisted processes for flue gas treatment and deodorization are described. Current trends and concepts will be discussed. 相似文献
994.
Ravi Mohan Prasad Yuji Iwamoto Ralf Riedel Aleksander Gurlo 《Advanced Engineering Materials》2010,12(6):522-528
The hydrogen and carbon monoxide separation is an important step in the hydrogen production process. If H2 can be selectively removed from the product side during hydrogen production in membrane reactors, then it would be possible to achieve complete CO conversion in a single‐step under high temperature conditions. In the present work, the multilayer amorphous‐Si‐B‐C‐N/γ‐Al2O3/α‐Al2O3 membranes with gradient porosity have been realized and assessed with respect to the thermal stability, geometry of pore space and H2/CO permeance. The α‐Al2O3 support has a bimodal pore‐size distribution of about 0.64 and 0.045 µm being macroporous and the intermediate γ‐Al2O3 layer—deposited from boehmite colloidal dispersion—has an average pore‐size of 8 nm being mesoporous. The results obtained by the N2‐adsorption method indicate a decrease in the volume of micropores—0.35 vs. 0.75 cm3 g?1—and a smaller pore size ?6.8 vs. 7.4 Å—in membranes with the intermediate mesoporous γ‐Al2O3 layer if compared to those without. The three times Si‐B‐C‐N coated multilayer membranes show higher H2/CO permselectivities of about 10.5 and the H2 permeance of about 1.05 × 10?8 mol m?2 s?1 Pa?1. If compared to the state of the art of microporous membranes, the multilayer Si‐B‐C‐N/γ‐Al2O3/α‐Al2O3 membranes are appeared to be interesting candidates for hydrogen separation because of their tunable nature and high‐temperature and high‐pressure stability. 相似文献
995.
Ángela França Beatriz Pelaz María Moros Christian Sánchez‐Espinel Andrea Hernández Cristina Fernández‐López Valeria Grazú Jesús M. de la Fuente Isabel Pastoriza‐Santos Luis M. Liz‐Marzán África González‐Fernández 《Small (Weinheim an der Bergstrasse, Germany)》2010,6(1):89-95
Nanoparticles (NPs) can offer many advantages over traditional drug design and delivery, as well as toward medical diagnostics. As with any medical device or pharmaceutical drug intended to be used for in vivo biomedical applications, NPs must be sterile. However, very little is known regarding the effect of sterilization methods on the intrinsic properties and stability of NPs. Herein a detailed analysis of physicochemical properties of two types of AuNPs upon sterilization by means of five different techniques is reported. In addition, cell viability and production of reactive oxygen species are studied. The results indicate that sterilization by ethylene oxide seems to be the most appropriate technique for both types of NPs. It is concluded that it is crucial to test several methods in order to establish the specific type of sterilization to be performed for each particular NP. 相似文献
996.
Lippke Sonia; Fleig Lena; Pomp Sarah; Schwarzer Ralf 《Canadian Metallurgical Quarterly》2010,55(4):398
Objective: For stage-matched interventions, individuals must be classified with respect to their previous behaviors and in conjunction with their future intentions. A novel procedure for the assessment of stages in physical activity was developed. For this, individuals' activity and their regarding intentions were compared with recommended levels of activity. The aim was to examine the psychometric properties. Design: In a cross-sectional study, stages were assessed in 366 study participants (84 in cardiac and 282 in orthopedic rehabilitation) in terms of their previous physical activity and their intention to perform recommended activity levels in the future. Main Outcome Measures: Stages of change were compared to self-reported behavior, intention, planning, self-efficacy, risk perception, pros, cons, and social support. Misclassification, sensitivity, specificity, receiver operating characteristic (ROC) curves, non-linear trends, and planned contrasts were computed. Results: In comparison to previous studies, sensitivity (44%–99%) was high and specificity was similar or low (3%–88%), depending on the type of validation outcome selected. When using less demanding criteria (i.e., less intensive activity), measurement quality decreased, although not always significantly. Applying contrast analyses, more than half of the predicted stage differences were confirmed. No main differences between orthopedic and cardiac, ambulant and stationary rehabilitation appeared and no interactions were found. Conclusion: The stage algorithm proved to have acceptable measurement qualities in study participants recruited in both cardiac and orthopedic rehabilitation. Especially in detecting Intenders and Actors the stage algorithm performed well. Mechanisms of adopting and maintaining recommended activity levels seem to operate equally in both groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
997.
Phase equilibria in the n-hexadecane-water-hydrogen and n-hexadecane-benzene-water-hydrogen systems were determined experimentally at temperatures between 200 and 350°C and pressures between 100 and 300 bar. At high water concentrations, three-phase equilibria were observed. Two-phase regions could be correlated with a modified Redlich-Kwong equation of state. The influence of interaction parameters on the calculated miscibility gaps was investigated. On application of mean interaction parameters, it is possible to calculate phase equilibria at different pressures or temperatures with the same set of parameters. In the ternary system, the three-phase regions could be calculated from the correlated binodal curves of two-phase regions. In the quaternary system, cross-sections through the vapour-liquid miscibility gap could be successfully correlated. 相似文献
998.
This paper describes a pilot plant for entrainment measurements on various types of column trays. The data obtained from different trays differ by up to a factor of 10. The measurements were compared with the theoretical model of Stichlmair. The Stichlmair entrainment diagram permits a fairly accurate prediction for most types of trays if the height of the two-phase layer is known. Prediction of the height and relative liquid hold-up in this two-phase system should be modified by a term reflecting the vapour flow profile, which requires further testing. These tests should examine the effect of tray spacing, fractional free area and, in particular, the influence of different media. 相似文献
999.
1000.