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排序方式: 共有2339条查询结果,搜索用时 31 毫秒
81.
Shiva Bejugama Shibu Chameettachal Falguni Pati Ajoy Kumar Pandey 《Ceramics International》2021,47(2):1594-1601
Niobia (1 mol. %) doped Ceria Stabilized Zirconia (NbCSZ) powders were synthesized using a co-precipitation method. The synthesized powders were uniaxially compacted and sintered in air. The two-step sintering method was adopted to sinter the samples, and the sintering schedule was optimized based on density, grain size, the phase present, and the hardness of the sintered sample. It was observed that the two-step sintering method effectively suppressed the grain growth of NbCSZ samples and helped in achieving a finer grain size of 1.57 μm along with the hardness of 1195 HV10 and optimum fracture toughness value 6.20 MPa m1/2. The Low-Temperature Degradation (LTD) behavior of the sintered samples was estimated through an accelerated hydrothermal aging test, which revealed that the samples are highly resistant to LTD and shown no phase change even after 150 h of study. Moreover, the cytocompatibility of the NbCSZ was tested by culturing MG63 cells on the samples for 7 days. The NbCSZ was found to be highly biocompatible as evident from cell viability and metabolic activity assay. 相似文献
82.
Effect of hydrogen enrichment on performance,combustion, and emission of a methanol fueled SI engine
B.S. Nuthan Prasad Jayashish Kumar Pandey G.N. Kumar 《International Journal of Hydrogen Energy》2021,46(49):25294-25307
The study of potentially high rated alternative fuel (Methanol) for the IC engines is an exciting topic in the recent research advancement. However, the study of combination of methanol and hydrogen is considered to address both economic and environmental needs. Hydrogen with best combustion characteristics will compensate for the drawbacks of methanol as a fuel. In the present investigation hydrogen enrichment to methanol has shown a significant enhancement in performance and combustion; the overall emission has reduced substantially. The experiments for a different set of trials, including hydrogen enrichment ranging between 5% and 20% with 2.5% increment, the engine is operated with wide-open throttle (WOT) condition for different speeds. The increase in enrichment of hydrogen has shown a rise in BTE, BP, and a reduced BSEC value. The percentage increase in BTE is between 20 and 30%, and an increase in hydrogen beyond 12.5% would affect the volumetric efficiency, and thus performance declines after that. The exhaust emissions have a huge impact on hydrogen enrichment; CO, HC, and CO2 emission are reduced by 30–40%; however, an increase in cylinder temperature due to rapid combustion slightly increases the NOx emission. Thus hydrogen enriched methanol operating at higher compression ratio can improve the overall engine characteristics significantly. 相似文献
83.
Vivek Pandey Michael Seese João M. Maia David A. Schiraldi 《Polymer Engineering and Science》2020,60(10):2511-2516
Three chain extenders, pyromellitic dianhydride (PMDA), ethylene carbonate (EC), and a polymeric-epoxide, were investigated for improving recycled p(ethylene terephthalate) (r-PET) properties with melt extrusion. The amount of additives and processing temperatures were also varied to check for melt degradation. Small amplitude oscillatory shear experiments were performed to probe rheological changes with different chain extenders. Capillary rheometry with haul-off was also performed to measure extensional viscosity and melt strength. Higher loadings of the chain extenders were found to improve properties of r-PET. These chain extenders definitely increased melt viscosities when incorporated at the higher level of the ranges examined, matching that of virgin PET. EC addition resulted in high shear thinning of the polymer. Epoxy and PMDA added to r-PET produced products with the same extensional viscosity as v-PET. Haul-off experiments demonstrate superior performance by epoxy-modified r-PET compared to v-PET. 相似文献
84.
Pandey Mamta Litoriya Ratnesh Pandey Prateek 《Wireless Personal Communications》2019,107(4):1687-1708
Wireless Personal Communications - Increased dominance of mobile applications (henceforth, app) over conventional software applications is quite apparent; however, there is a lack of structured... 相似文献
85.
Shahi Vivek Alizadeh Vahidreza Amirkhizi Alireza V. 《Mechanics of Time-Dependent Materials》2021,25(3):447-471
Mechanics of Time-Dependent Materials - The aim of this study is to investigate the role of chain length and hard segment dispersion within the soft segment on thermo-mechanical properties of a... 相似文献
86.
Applied Intelligence - This paper presents techniques to improve the prediction accuracy of approximation methods used in Gaussian process regression models. Conventional methods such as... 相似文献
87.
Sanjeev Kumar Pandey S. L. Patil Praveen V. Pol S. B. Phadke 《International Journal of Electronics》2020,107(10):1682-1703
ABSTRACT In this paper, two control schemes for boost converters affected by uncertainties in input voltage and load are proposed. The boost converter dynamics is redefined in terms of new state variables to facilitate the use of a disturbance observer that can estimate matched and unmatched disturbances. A sliding surface, which is new in the context of boost converters, is proposed to enable tracking and regulation of output voltage without requiring measurement of input voltage and load current. The stability of the overall system including the disturbance observer, the sliding variable and the output is proved. The performance of the schemes is assessed for regulation of output voltage and tracking of reference voltage by simulation as well as experimentation in which various types of uncertainties and various types of reference voltages are considered. 相似文献
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