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排序方式: 共有215条查询结果,搜索用时 15 毫秒
31.
32.
Shivani Dhall Kapil Sood Rashi Nathawat 《International Journal of Hydrogen Energy》2017,42(12):8392-8398
Fast detection of H2 gas at room temperature has constantly remained a challenge. The metal-oxide based gas sensors have shown excellent sensing properties for gases like H2, NO, CO and NH3. In the present work, the H2 gas sensing characteristics of multiwalled carbon nanotubes based hybrid sensor (F-MWCNTs/TiO2/Pt) has been reported. The fabricated sensor shows 3.9% sensitivity for low concentration i.e. 0.05% of H2 with good repeatability and stability at room temperature. The sensing response of F-MWCNTs/TiO2/Pt is interrelated to change in their resistance on the introduction of H2 gas and this phenomenon is required for deep understanding the effect of H2 adsorption on their electronic conduction. The improvement in sensitivity of F-MWCNTs/TiO2/Pt as compared to MWCNTs/TiO2 towards H2 is because of the catalytic role of dispersed Pt nanoparticles deposited by sputtering. 相似文献
33.
Sr substituted LaInO3 compounds have been prepared by the conventional solid state reaction method. The as-prepared samples are characterized by
X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), differential thermal analysis (DTA), thermal expansion coefficient
(TEC), and impedance spectroscopy. The XRD analysis of LSI 20 shows the formation of single phase La0.9Sr0.1InO2.95 compound. However, the higher substitution of Sr2+ for La3+ leads to the formation of secondary insulating phase, i.e., SrIn2O4. Sr substitution leads to anionic vacancy which is the possible mechanism for ionic conduction in the given system. Reitveld
refinement confirms orthorhombic phase formation in all the samples except LSI 23 (La0.77Sr0.23InO2.89) which is well fitted monoclinic phase. TEC is nearly 9.1 × 10−6 °C−1 in the range of 500–1000 °C in LSI 20 sample. The ionic conductivity is 0.11 mS cm−1 at 800 °C in single phase LSI 20 sample. The solid solubility limit is x = 0.20 which is higher than earlier reported values for similar systems. 相似文献
34.
Valenstein JS Kandel K Melcher F Slowing II Lin VS Trewyn BG 《ACS applied materials & interfaces》2012,4(2):1003-1009
A series of 2d-hexagonally packed mesoporous silica nanoparticle material with 10 nm pore diameter (MSN-10) covalently functionalized with organic surface modifiers have been synthesized via a post-synthesis grafting method. The material structure has been characterized by powder X-ray diffraction, electron microscopy, and nitrogen sorption analyses, and the free fatty acid (FFA) sequestration capacity and selectivity was investigated and quantified by thermogravimetric and GC/MS analysis. We discovered that aminopropyl functionalized 10 nm pore mesoporous silica nanoparticle material (AP-MSN-10) sequestered all available FFAs and left nearly all other molecules in solution from a simulated microalgal extract containing FFAs, sterols, terpenes, and triacylglycerides. We also demonstrated selective FFA sequestration from commercially available microalgal oil. 相似文献
35.
Mahesh Paidpilli Kapil Verma Rajat Pandey Anish Upadhyaya 《Transactions of the Indian Institute of Metals》2017,70(8):2017-2026
In the present work, one batch of prealloyed 6061Al powder was mixed with different lead compositions (5, 10, 15 vol.%) and another set with same composition was ball-milled for 5 h at 300 rpm. Microstructural features such as lattice constant, crystallite size, particle size and morphology were studied using XRD, particle size analyzer and SEM. Both the as-mixed as well as ball-milled powders were compacted at 300 MPa and sintered under N2 atmosphere for 1 h in tube furnace at 590 °C. The ball milling of 6061Al alloy powder improved sinter density and densification while lead addition showed negligible influence on these parameters. The microstructure of as-mixed 6061Al–Pb alloys exhibited equiaxial morphology whereas ball-milling resulted in elongated grains with uniform lead distribution. Quasi-static compressive mechanical behavior was investigated for 6061Al–Pb alloys at 1 × 10?3 s?1 strain rate. Results indicated that ultimate compressive and yield strength were sensitive to milling and lead volume fraction. 相似文献
36.
Multi-objective parametric optimization on machining with wire electric discharge machining 总被引:1,自引:1,他引:0
Kapil Kumar Sanjay Agarwal 《The International Journal of Advanced Manufacturing Technology》2012,62(5-8):617-633
The selection of optimum machining conditions, during wire electric discharge machining process, is of great concern in manufacturing industries these days. The increasing quality demands, at higher productivity levels, require the wire electric discharge machining process to be executed more efficiently. Specifically, the material removal rate needs to be maximized while controlling the surface quality. Despite extensive research on wire electric discharge machining process, determining the desirable operating conditions in industrial setting still relies on the skill of the operators and trial-and-error methods. In the present work, an attempt has been made to optimize the machining conditions for maximum material removal rate and maximum surface finish based on multi-objective genetic algorithm. Experiments, based on Taguchi’s parameter design, were carried out to study the effect of various parameters, viz. pulse peak current, pulse-on time, pulse-off time, wire feed, wire tension and flushing pressure, on the material removal rate and surface finish. It has been observed that a combination of factors for optimization of each performance measure is different. So, mathematical models were developed between machining parameters and responses like metal removal rate and surface finish by using nonlinear regression analysis. These mathematical models were then optimized by using multi-objective optimisation technique based on Non-dominated Sorting Genetic Algorithm-II to obtain a Pareto-optimal solution set. 相似文献
37.
One of the key performance indicators for designing site utility systems is cogeneration potential for the site. A new method has been developed to estimate cogeneration potential of site utility systems by a combination of bottom-up and top-down procedures, which allows systematic optimization of steam levels in the design of site utility configurations. A case study is used to illustrate the usefulness of the new cogeneration targeting method and benefits of optimizing steam levels for reducing the overall energy consumptions for the site. Techno-economic analysis has been carried out to improve heat recovery of low-grade waste heat in process industries, by addressing a wide range of low-grade heat recovery technologies, including heat pumping, organic Rankine cycles, energy recovery from exhaust gases, absorption refrigeration and boiler feed water heating. Simulation models have been built for the evaluation of site-wide impact associated with the introduction of each design option in industrial energy systems in the context of process integration. Integration of heat upgrading technologies within the total site has been demonstrated with a case study for the retrofit scenario. 相似文献
38.
R. K. Garg Kapil Sharma C. K. Nagpal Rakesh Garg Rajpal Garg Rajive Kumar Sandhya 《Software Testing, Verification and Reliability》2013,23(2):149-168
This research paper presents a framework for ranking of software engineering metrics based on expert opinion elicitation and fuzzy‐based matrix methodology. The proposed methodology is able to accommodate the imprecise and inexact data involved in the problem of ranking of software engineering metrics, vagueness and ambiguity occurring during expert (human) decision making and to depart from the complexity of formulation of the objective and the constraint function. The matrices lend themselves to mechanical manipulations and are useful for analyzing and deriving systems functions expeditiously to meet the objectives. The current research is based on software engineering metrics identified in an earlier study conducted by Lawrence Livermore National Laboratory. A set of ranking criteria were identified. Software engineering metrics are then ranked in ascending order using experts' opinion in accordance with the value of Permanent function on their criteria matrix. The proposed methodology has also been compared with other known methodologies. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
39.
40.
Gunghas Ankush Kumar Sunil Sheoran Devender Kalkal Kapil Kumar 《International Journal of Mechanics and Materials in Design》2020,16(4):767-782
International Journal of Mechanics and Materials in Design - Present research is concerned with the study of two-dimensional disturbances in a non-homogeneous, isotropic, thermoelastic medium with... 相似文献