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1.
Various softwood and hardwood bark residues, primary sludges and softwood sawdust residues were processed by vacuum pyrolysis in a laboratory scale batch reactor. The pyrolysis oil, water, charcoal, and gas were recovered and analyzed. The pyrolysis oils were analyzed in details for their content in phenolic compounds after derivatization to their acetyl derivatives. The influence of temperature, heating rate, feedstock bed thickness, particle size and feedstock water pretreatment on the yield of phenols was investigated. The highest yield of phenols was obtained when hardwood bark was soaked in water for 48 hours and pyrolyzed at a temperature of 450°C and a heating rate of 10°C/min. Pyrolysis performance was evaluated in terms of total phenolic yield and composition. 相似文献
2.
Branched-chain/cyclic alkanes have been obtained, by solvent extraction and molecular-sieve adsorption, from a UK low-temperature (Rexco) coal tar, a USA fluidized-bed pyrolysis (FMC COED) coal tar, and a novel supercritical-gas-extract of a Turkish (Elbistan) lignite. Mass spectrometry (with gas chromatography and field-desorption) established the presence of mono-, di (including sesquiterpanes), tri-, tetra- (steranes only), and pentacyclic (triterpanes only) alkanes, including several steranes and triterpanes not previously reported as coal-tar constituents. The potential of cyclic alkanes as geochemical markers, even for commercial coal products subjected to appreciable heat treatment, is demonstrated by the identification of C12, C13, C15 and C16 dicyclics (including isoprenoid alkanes), C17-C26 tricyclics, and C27 and C29 hopane-type pentacyclics (triterpanes) in FMC, and of C16-C38 monocyclics, C34-C36 dicyclics, C22-C36 tricyclics, C27-C30 tetracyclics (steranes), and C27, C29, C30, C31, C32, and C33 hopane-type pentacyclics (triterpanes) in Rexco tar. Tetra- and pentacyclic alkanes were also preserved in the lignite extract. 相似文献
3.
In this article, the design and realization of waveguide filter with improved stop‐band response is presented. By inserting transversal slots at the proper position of cavities, without disturbing the field distribution of the dominant mode, the second longitudinal resonant modes are radiated out. This caused the out‐of‐band frequency response of the filter to be improved. The validity of the proposed technique is confirmed by comparison between measurement values and simulation results from the finite element method through the commercial software (high frequency structure simulator). Also, to assure electromagnetic compatibility the slot surfaces are covered by absorbing material. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011. 相似文献
4.
Nicholas J. Kybert Gang Hee Han Mitchell B. Lerner Eric N. Dattoli Ali Esfandiar A. T. Charlie Johnson 《Nano Research》2014,7(1):95-103
Arrays of chemical vapor sensors based on graphene field effect transistors functionalized with single-stranded DNA have been demonstrated. Standard photolithographic processing was adapted for use on large-area graphene by including a metal protection layer, which protected the graphene from contamination and enabled fabrication of high quality field-effect transistors (GFETs). Processed graphene devices had hole mobilities of 1,640 ± 250 cm2.V-1.s-1 and Dirac voltages of 15 ± 10 V under ambient conditions. Atomic force microscopy was used to verify that the graphene surface remained uncontaminated and therefore suitable for controlled chemical functionalization. Single-stranded DNA was chosen as the functionalization layer due to its affinity to a wide range of target molecules and π-π stacking interaction with graphene, which led to minimal degradation of device characteristics. The resulting sensor arrays showed analyte- and DNA sequence-dependent responses down to parts-per-billion concentrations. DNA/GFET sensors were able to differentiate among chemically similar analytes, including a series of carboxylic acids, and structural isomers of carboxylic acids and pinene. Evidence for the important role of electrostatic chemical gating was provided by the observation of understandable differences in the sensor response to two compounds that differed only by the replacement of a (deprotonating) hydroxyl group by a neutral methyl group. Finally, target analytes were detected without loss of sensitivity in a large background of a chemically similar, volatile compound. These results motivate further development of the DNA/graphene sensor family for use in an electronic olfaction system. 相似文献
5.
Amir Saeid Pakdel Mohammad Reza Saeb Hossein Abedini Hossein Ali Khonakdar Regine Boldt 《Polymer Bulletin》2014,71(10):2487-2506
This work is targeted to study emulsion polymerization of vinyl chloride monomer (VCM) using experimental and mathematical methods. To fulfill this goal, a computer code was developed on the basis of zero–one population balance by which the effects of initiator and emulsifier concentration on the evolution of VCM conversion were investigated in the course of polymerization. The model was also trained to capture the coagulation of the particles. This enabled to adopt a reliable way of evaluating the particle size distribution (PSD). In particular, the rates of homogeneous and micellar nucleation mechanisms were simulated and reasonably predicted alterations in the PSD and the number of polymer particles under the influence of aforementioned parameters. The results from modeling were satisfactorily consistent with the experimental outputs and obviously visualized the impact of initiator and surfactant concentration on the PSD of the prepared PVC latexes. 相似文献
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7.
Evolution of vinyl chloride conversion below critical micelle concentration: A response surface analysis 下载免费PDF全文
Amir Saeid Pakdel Mohammad Rezaei Behbahani Mohammad Reza Saeb Hossein Ali Khonakdar Hossein Abedini Mehdi Moghri 《乙烯基与添加剂工艺杂志》2015,21(3):157-165
Utilizing response surface methodology, the conversion of vinyl chloride monomer (VCM) was monitored when the polymerization temperature, the type of surfactant, and the weight ratio of water‐to‐monomer (W/M) were taken as the emulsion polymerization variables. Because the homogeneous nucleation was found to be the dominant mechanism in VCM emulsion polymerization, irrespective of the surfactant concentration, the whole experiments have been carried out below critical micelle concentration of the used surfactants. Among all the studied variables, the polymerization temperature appeared as the most effective parameter; moreover, its interactive effect with W/M caused different trends in the alteration of final conversion being observed. Also, depending on the reaction temperature, the VCM conversion would be affected by the type of the surfactant used. Contrarily, simultaneous change in the type of surfactant and W/M revealed an insignificant effect on the evolution of VCM conversion. The optimization of final conversion of VCM was also accessible through contour plots of response surface methodology. It is worth noting that, taking a conventional approach into consideration, the alteration of VCM conversion seemed to be a monotonic function of temperature. J. VINYL ADDIT. TECHNOL., 21:157–165, 2015. © 2014 Society of Plastics Engineers 相似文献
8.
The Journal of Supercomputing - In wireless sensor networks (WSNs), designing a stable, low-power routing protocol is a major challenge because successive changes in links or breakdowns destabilize... 相似文献
9.
Esfandiar Gharibaan 《中国电梯》2011,(16):32-38
正如大家所知道,EN81是最基础的安全方面的标准,广泛应用于全世界很多地方。1EN81标准体系(1)电梯标准体系结构表如图1,包括:技术规范、评价体系、斜行电梯、远程监控、货梯、地震情况下电梯要求等各种规范。其中EN81-80,安全性提高,已经转化为中国国标。 相似文献
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