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101.
Oxidative steam reforming of propane was tested over four Pt–Ni/δ-Al2O3 bimetallic catalysts aiming to investigate the effect of metal loadings and Ni:Pt loading ratio on catalyst performance. A trimetallic Pt–Ni–Au/δ-Al2O3 catalyst was additionally studied aiming to understand the effect of Au presence. Reaction temperature, carbon to oxygen ratio, and residence time were taken as the reaction parameters. The effect of C/O2 ratio on the hydrogen production and H2/CO selectivity was found dependent on the Pt and Ni loadings. The results underlined the importance of C/O2 ratio as an optimization parameter for product distribution. The highest hydrogen production and H2/CO ratio levels were obtained for the highest C/O2 ratio tested. An optimum Ni:Pt weight ratio was found around 50 due to suppressed methanation and enhanced hydrogen production activities of these catalysts. The presence of gold in the trimetallic catalyst caused poor activity and selectivity in comparison to bimetallic catalysts. 相似文献
102.
Strength development and chloride penetration in rubberized concretes with and without silica fume 总被引:5,自引:2,他引:3
The study presented herein has been carried out in order to investigate the strength development and chloride permeability
characteristics of plain and rubberized concretes with and without silica fume. For this purpose, two types of tire rubber,
namely crumb rubber and tire chips, were used as fine and coarse aggregate, respectively, in the production of rubberized
concrete mixtures which were obtained by partially replacing the aggregate with rubber. Two water-cementitious material (w/cm)
ratios (0.60 and 0.40), three moist curing periods (3, 7, and 28 days), four designated rubber contents (0, 5, 15, and 25
by total aggregate volume), two silica fume content (0 and 10% by weight of cement), and five different testing ages (3, 7,
28, 56, and 90 days) were considered as experimental parameters. The results indicated that for a given w/cm ratio and moist
curing period, the use of rubber significantly aggravated the chloride ion penetration through concrete but the degree of
the rate of the increment of the chloride permeability depended on the amount of the rubber used. When the curing period was
extended from 3 to 28 days, the reduction in the magnitude of chloride penetration depth was notably higher for the rubberized
concretes, even at a rubber content of as high as 25%. It was also observed that silica fume may be considered as a remedy
to enhance the chloride penetration resistance of the rubberized concretes. 相似文献
103.
Abstract Two precipitates were obtained from original black liquor by using hydrochloric acid and carbon dioxide. The precipitates were liqufied and gasificated by non-catalytic and catalytic runs at gradually elevated temperatures. The amount of gaseous products increased with increasing temperature and percent of catalyst. The percent of hydrogen in the obtained gas mixture was the highest in potassium carbonate catalytic runs (37 %). 相似文献
104.
Ramazan Erdem Metin Yüksek Erhan Sancak Onur Atak Merve Erginer Levent Kabasakal 《纺织学会志》2017,108(6):935-946
Optimized electrospinning conditions were applied to produce single and multilayered (ML) scaffolds composed of polycaprolactone, collagen and elastin. The ML scaffold was cross-linked with glutaraldehyde to increase the stability. Morphological and structural characteristics of the scaffolds were measured by SEM and FTIR analyses. Results revealed that polymers combined to each other well and uniform fibers were obtained with the diameters ranging from 156 ± 53 to 1536 ± 293 nm. Contact angle measurements were performed to investigate the hydrophilic character of each structure. It was observed that incorporation of the natural polymers into the blends increased the hydrophilicity. Mechanical tests proved that collagen contributed to fabricate stiffer structures while elastin provided more elasticity. Biocompatibility of the scaffolds was examined by SEM analysis and WST-1 test with mouse fibroblast cells (L929) in vitro. Results exhibited that the addition of natural polymers increased the cell growth, and none of the single and ML scaffolds presented cytotoxic effect. 相似文献
105.
New methodology is suggested to quantify the effect of temperature on oxidative degradation and compare test results obtained at different temperatures or evaluate changes in chemical mechanisms. Assumption of the pseudo-first-order kinetics to calculate activation energies in oxidative polymerization of uninhibited 100 percent oleic triglyceride under thin film oxidation provided only semiquantitative results from available oxypolymerization data at six temperatures from 100° to 175°C. As an alternative approach, Time and Temperature Superposition (TTS) was applied to analyze the data. Several TTS forms consistent with Arrhenius equation showed much greater accuracy in determining activation energies and induction periods. Different stages of oxidative degradation were identified after the data from different temperatures were combined into one kinetic map. Kinetic maps of alkali-refined high oleic sunflower oil, fully formulated synthetic oleate-based hydraulic fluid and additive-free super refined mineral oil showed their increasing resistance to oxypolymerization. Limitations of TTS were discussed. 相似文献
106.
Mehmet Kobya Erhan Gengec Mehmet Tonay Sensoy Erhan Demirbas 《Coloration Technology》2014,130(3):226-235
Textile dyeing wastewater was treated by electrocoagulation using aluminium and iron plate electrodes. Response surface methodology and central composite design were applied in the experiments and in statistical data analysis. A current density of 30–100 A m?2, an initial pH of 4–8, and an operating time of 10–40 min were chosen as independent variables, and the chemical oxygen demand, total organic carbon, and turbidity removal efficiencies and the operating cost were selected as responses in the electrocoagulation process. The developed quadratic models for the responses and the experimental data were in good agreement with model predictions statistically (R2 ≥ 0.92, Adj R2 ≥ 0.82, and Prob > F < 0.004). The optimised operating variables (initial pH, current density, and operating time) and the maximum total organic carbon, chemical oxygen demand, and turbidity removal efficiencies for textile dyeing wastewater were 5.5, 63.2 A m?2, 30.4 min, 77%, 82%, and 94% for the iron electrode and 5.6, 52.5 A m?2, 33.9 min, 68%, 69% and 99% for the aluminium electrode respectively. Minimum operating costs for the iron and aluminium electrodes under optimum conditions were €2.1 m?3 (€1.0 kg?1 COD) and €2.4 m?3 (€1.6 kg?1 COD). The iron electrode was found to be superior to the aluminium electrode in terms of removal efficiencies and operating cost for the treatment of textile dyeing wastewater. 相似文献
107.
The present study demonstrated the applicability of the electrocoagulation method for the removal of reactive dye, Remazol Red 3B, in a batch study. Iron electrode material was used as a sacrificial electrode in monopolar parallel mode in this study. The effects of the initial pH, current density, conductivity, initial concentration of dye and electrolysis time on the removal of Remazol Red 3B were investigated to determine optimum operating conditions. High decolorisation efficiency (>99%) for Remazol Red 3B dye solution was obtained with optimal value of process parameters, such as 15 mA cm?2 of current density, 10 min of electrolysis time, pH 6 and 500 mg l?1 dye concentration. The energy consumption, electrode consumption and operating costs under optimum operating conditions were calculated as 3.3 kW h kg dye?1, 1.2 kg Fe kg dye?1 and 0.6 € m?3, respectively. 相似文献
108.
Saadettin Erhan Kesen Sanchoy K. Das Zulal Gungor 《The International Journal of Advanced Manufacturing Technology》2010,47(5-8):665-678
We present a multi-objective mixed integer programming formulation for job scheduling in virtual manufacturing cells (VMCs). In a VMC, machines are dedicated to a part family as in a regular cell, but machines are not physically relocated in a contiguous area. Cell configurations are therefore temporary, and assignments are made to optimize the scheduling objective under changing demand conditions. We consider the case where there are multiple jobs with different processing routes. There are multiple machine types with several identical machines in each type and are located in different locations in the shop floor. The two scheduling objectives are makespan minimization and minimizing total traveling distance. Since batch splitting is permitted in the system, scheduling decisions must tell us the (a) assignment of jobs to the machines, (b) the job starting time at each machine, and (c) the part quantity processed on different machines due to batch splitting. Under these decision variables, the objective function is to minimize the sum of the makespan and total traveling distance/cost. Illustrative examples are given to demonstrate the implementation of the model. 相似文献
109.
We report the fabrication of single-walled carbon nanotube (SWNT) DNA sensors and the sensing mechanism. The simple and generic protocol for label-free detection of DNA hybridization is demonstrated with random sequence 15mer and 30mer oligonucleotides. DNA hybridization on gold electrodes, instead of on SWNT sidewalls, is mainly responsible for the acute electrical conductance change due to the modulation of energy level alignment between SWNT and gold contact. This work provides concrete experimental evidence on the effect of SWNT-DNA binding on DNA functionality, which will help to pave the way for future designing of SWNT biocomplexes for applications in biotechnology in general and also DNA-assisted nanotube manipulation techniques. 相似文献
110.