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排序方式: 共有664条查询结果,搜索用时 267 毫秒
1.
Naser Hosseini Ali Fazili Mohammad Reza Derakhshandeh Leila Nikzad Milad Bahamirian Mansour Razavi 《Ceramics International》2021,47(11):15771-15782
In this study, the effect of Co addition on microstructural and mechanical properties of WC-B4C–SiC composites sintered by spark plasma sintering (SPS) method was investigated. For this purpose, three batches of WC-B4C–SiC with different contents of Co (10 vol%, 15 vol%, and 20 Vol %) were sintered at 1400 °C. The results of X-ray diffraction (XRD) analysis of the samples indicated the formation of W2B5, W3CoB3 as well as the remained C phases and unreacted SiC phase. It was observed that by increasing the Co content, the amount of W2B5 phase reduces and W3CoB3 and C contents increase. Therefore, W2B5 peaks were not detected in the sample containing 20vol% Co. Relative density values above 97% were obtained for all the composites. However, a decrease was observed in relative density by increasing the Co content in the composites. The highest flexural strength (510 ± 42 MPa), fracture toughness (10.34 ± 0.82 MPa m1/2), and hardness (20.63 ± 0.75 GPa) were also obtained for the sample containing 10vol% Co compared to the other samples. In addition, Transgranular fracture of SiC as well as pulling out of W3CoB3 and W2B5 particles were observed in the fracture surface micrographs of the samples. The presence of micro-cracks in the SiC grains, fracture of W3CoB3 grains, and crack deflection was reported as dominant toughening mechanisms. 相似文献
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ABSTRACTThis article examines equity concerns and inherent conflicts related to rural–urban water supply allocation and use, with focus on Metro Manila. Going beyond the much-discussed difficulty farmers experience from an allocation policy prioritizing urban water requirements, it shows that inequity in raw water allocation is linked to, and further exacerbated by, inequities in urban domestic water provision. Moreover, it highlights the need for broader equity reviews, using the concept of the rural–urban water equity nexus to draw attention to key equity considerations across space and scale that otherwise might remain invisible. 相似文献
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Carla C. B. Brasil Cristiano R. de Menezes Eduardo Jacob-Lopes Juliano Smanioto Barin Leila Queiroz Zepka Paulo Cezar Bastianello Campagnol Roger Wagner Alexandre José Cichoski 《International Journal of Food Science & Technology》2020,55(3):1136-1144
This study investigated the effect of the combination of basic electrolysed water (BEW) and slightly acid electrolysed water (SAEW) with ultrasound (US) for cleaning and sanitation of the knives used in slaughtering processes. The knives were sonicated in a US bath using two modes of operation (normal and sweep) in two steps: (i) 5 min with BEW and (ii) 10 min with SAEW at 35 °C. The microbiological counts and the possible changes in the physical structure of the knives were evaluated. The association BEW + SAEW + US, in the sweep mode, provided lower mesophilic, enterobacterial, Staphylococcus aureus and yeast counts when compared to the values recommended by the international legislation. In addition, these conditions removed all organic residues from the knife blades and promoted the highest migration rate of the residues to the US water bath (12.35 mg/L·min), without modifications in the knife blades. Thus, cleaning and sanitation of knives was feasible with the association of BEW + SAEW + US, which could be a useful alternative for the meat industry. 相似文献
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One of the methods of pollution separating from urban and industrial wastewater is the use of composite membranes based on polymer. The modified composite 相似文献
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Simulation of Propane Dehydrogenation to Propylene in a Radial‐Flow Reactor over Pt‐Sn/Al2O3 as the Catalyst 下载免费PDF全文
Seyed M. Miraboutalebi Leila Vafajoo Mohammad Kazemeini Moslem Fattahi 《化学工程与技术》2015,38(12):2198-2206
Catalytic paraffin dehydrogenation for manufacturing olefins is considered to be one of the most significant production routes in the petrochemical industries. A reactor kinetic model for the dehydrogenation of propane to propylene in a radial‐flow reactor over Pt‐Sn/Al2O3 as the catalyst was investigated here. The model showed that the catalyst activity was highly time dependent. In addition, the component concentrations and the temperature varied along the reactor radius owing to the occurring endothermic reaction. Moreover, a similar trend was noticed for the propane conversion as for the propylene selectivity, with both of them decreasing over the time period studied. Furthermore, a reversal of this trend was also revealed when the feed temperature was enhanced or when argon was added into the feed as an inert gas. 相似文献
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Ahmadi Hossein Arji Goli Shahmoradi Leila Safdari Reza Nilashi Mehrbakhsh Alizadeh Mojtaba 《Universal Access in the Information Society》2019,18(4):837-869
Universal Access in the Information Society - The Internet of Things (IoT) is an ecosystem that integrates physical objects, software and hardware to interact with each other. Aging of population,... 相似文献
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In this study, wheat gluten fibers loaded by the azathioprine were fabricated and their physicochemical properties were studied. The nanofibers were characterized by using the scanning electron microscopy (SEM), Fourier transformed-infrared spectroscopy, X-ray diffractometry, thermogravimetric, and differential thermal analysis. The SEM images showed that the addition of polyvinyl alcohol decreased the fibers’ diameters. The diameters of 77.14?±?14.11?nm were obtained for the wheat gluten–polyvinyl alcohol loaded drug fibers. In addition, the cell viability evaluation conducted by the MTT assay proved no cytotoxicity of the prepared nonofibers at concentrations up to 4?mg/mL to human umbilical vein endothelial cell. 相似文献