SiCp-reinforced commercial pure magnesium and AZ91 alloy MMCs’ were prepared through infiltration route without the use of any
special atmospheres. The preform was prepared using a mixture of reinforcement particles and the matrix metal particles. The
composites were prepared with various volume percentage of the reinforcement and their properties with the variation of SiCp were analyzed. The interfacial properties of the composites were analyzed using microstructure, microhardness, and wear studies.
Calculation of thermal conditions during infiltration was done to study the effect of adding matrix metal particles on the
infiltration behavior and its effect on the uniformity distribution of the reinforcements. 相似文献
In the present investigation, the electrochromic properties of a fast protonic solid state device: NiOx/Ta2O5/WO3−x prepared at room temperature (300 K) is reported. The non-stoichiometric tungsten oxide thin film is prepared by reactive DC magnetron sputtering technique on ITO coated glass; the oxides of tantalum (300 nm) and nickel (100 nm) are prepared by electron beam evaporation. This proton device has a coloration efficiency of 82.4 cm2/C and coloration and bleaching time of 6 and 5 s, respectively, and a transmittance variation of 60%. The work function of WO3−x thin films by Kelvin probe in uncolored and colored states are 4.73 and 4.30 eV, respectively. 相似文献
SBA-15 and ZrO2 (10–50 wt.%) containing SBA-15 mesoporous materials were prepared by direct and post-synthesis methods. Characterization using low angle XRD, pore size distribution, CO2 chemisorption indicate that hexagonal mesoporous structure is retained even after ZrO2 addition (25 wt.%). Mo, CoMo and NiMo catalysts prepared using these supports were examined by XRD, oxygen chemisorption, temperature programmed reduction (TPR). The catalysts were tested for hydrodesulfurization (HDS) of thiophene and hydrogenation (HYD) of cyclohexene. HDS of thiophene for 8%Mo, 3%Co8%Mo, and 3%Ni8%Mo increases with increasing ZrO2 loading in SBA-15 up to 25 wt.%. Oxygen chemisorption and TPR hydrogen consumption indicated that the molybdenum dispersion and anion vacancies, and catalytic activities are significantly influenced by ZrO2 content in Zr-SBA-15. A comparison indicated that TiO2-SBA-15, ZrO2-SBA-15 supported CoMo catalysts show higher activities for hydrodesulfurization. 相似文献
Self-heating of coal during its storage and transportation has been a serious problem for decades. Coal stored in large piles for long duration is subjected to weathering by atmospheric air that prevails with different temperatures and moisture content. Chemisorption of atmospheric oxygen results in low-temperature oxidation of pile, which generates heat due to exothermic reactions. If the local heat release rate is higher as compared to the heat dissipated, a significant increase in temperature is possible and this results in spontaneous ignition of the pile. The presence of moisture in coal delays the occurrence of self-heating. This motivates to analyze a scenario of using moist coal to delay or even prevent the self-ignition in dry coal until a given time period of its storage. The main objective of this work is to investigate the critical conditions, which may lead to spontaneous ignition in large coal stockpiles containing dry and moist coal layers. A one-dimensional numerical model is used for this purpose. A parametric study is carried out considering different porosity, superficial air velocity and reactivity values. The time period of coal pile storage is fixed as 360 days. The location and time taken for self-ignition in the pile within this period is reported for each case. In summary, considering several cases, the simulations systematically reveal that highly reactive coal with high pile porosity and higher superficial gas velocity takes the least time to reach the self-ignition temperature.
Journal of Mechanical Science and Technology - In the present study, an endeavour has been made in trepanning of Duplex steel (DSS 2507) under wet and cryogenic environments. DSS 2507 steel is... 相似文献
In the recent years, particulate reinforced aluminum based matrix composites are playing an important role in automobile and aerospace applications due to their enhanced properties. In this work, an attempt has been made to optimize the tribological behaviour of aluminum 7075 matrix reinforced with titanium carbide (3 percent weight) and basalt particles (2 percent weight) using Taguchi based grey relational analysis. Composites are fabricated according to american society for testing materials standard using stir casting method dry sliding wear tests were carried out using pin on disc apparatus as per Taguchi's L9 orthogonal array. Grey relational analysis was used to obtain the optimum process parameters for multiple quality characteristics such as wear rate and coefficient of friction. Then significant contribution of wear parameters was determined by analysis of variance. A confirmatory test was carried out to validate the test result. Finally, the micro structural investigation on the worn surfaces was performed by scanning electron microscope. 相似文献
This study presents an experimental analysis of improving the thermal, electrical efficiency, and yield of a conventional solar still (CSS). The photovoltaic (PV) efficiency decreases with increase in water depth inside the basin while the still efficiency is higher in the case of fully submerged condition. The maximum water production was about 8 kg/m 2/day with PV under fully submerged condition; and during off‐shine hours the still efficiency was higher when compared with the partially submerged condition. Similarly, with a decrease in water temperature the panel efficiency is increases. The maximum hourly water production with and without the PV was found to be 1.3 and 0.45 kg/m 2, respectively. The main outcome of this study is that this mechanism can be used in isolated locations where there is a scarcity of current and distilled water. 相似文献
Malaria is considered a dreadful mosquito-borne infectious disease of human beings caused and spread by biting of the female mosquito Anopheles stephensi infected with a parasitic protozoan Plasmodium falciparum. Continuous application of chemicals/synthetic insecticides for vector control causes various problems such as resistant mechanism of mosquito, toxicity to nontarget aquatic organisms and disturbance to the microbial community of the soil. Currently, green synthesized nanoparticles are being employed in various biological processes including insect and pest control. The present investigation focused on the mosquito-larvicidal property of Turbinaria ornata-mediated gold nanoparticles (To-AuNPs) and its boiled aqueous extract (To-AE) against the malarial vector A. stephensi. The recorded lethal concentration (LC50 and LC90) values (µg/ml) of To-AE and To-AuNPs against fourth instar larvae of A. stephensi were 37.77 and 159.55 and 12.79 and 78.70, respectively. The To-AuNPs were characterized through UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive x-ray spectroscopy (EDX), zeta potential and dynamic light scattering (DLS) method. The presently synthesized gold nanoparticles through the single-step, eco-friendly method is a potentially effective mosquitocidal agent. 相似文献