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21.
Abdulaziz Attaallah Sabita Khatri Mohd Nadeem Syed Anas Ansar Abhishek Kumar Pandey Alka Agrawal 《计算机系统科学与工程》2021,37(3):313-329
A significant increase in the number of coronavirus cases can easily be noticed in most of the countries around the world. Inspite of the consistent preventive initiatives being taken to contain the spread of this virus, the unabated increase in the cases is both alarming and intriguing. The role of mathematical models in predicting and estimating the spread of the virus, and identifying various preventive factors dependencies has been found important and effective in most of the previous pandemics like Severe Acute Respiratory Syndrome (SARS) 2003. In this research work, authors have proposed the Susceptible-Infectected-Removed (SIR) model variation in order to forecast the pattern of coronavirus disease (COVID-19) spread for the upcoming eight weeks in perspective of Saudi Arabia. The study has been performed by using SIR model with a proposed simplification using average progression for further estimation of β and γ values for better curve fittings ratios. The predictive results of this study clearly show that under the current public health interventions, there will be an increase in the COVID-19 cases in Saudi Arabia in the next four weeks. Hence, a set of strong health primitives and precautionary measures are recommended in order to avoid and prevent the further spread of COVID-19 in Saudi Arabia. 相似文献
22.
We have measured the frictional responses of two silane molecules (Octadecyltrichlorosilane; OTS and 1H, 1H, 2H, 2H-Perfluorooctyltrichlorosilane;
FOTS) self-assembled on an aluminium substrate in their non heat-treated and heat-treated states. We varied the contact length
scale by performing the experiments in atomic force microscope, nanotribometer and macro scale pin-on-disc machine. We have
found that conformational disorder and molecular stiffness have major influences on friction in strongly distinguishing the
response of OTS from that of the FOTS molecules. The frictional identity between the two molecules before and after heat treatment,
though somewhat contrary to that suggested from purely surface energy considerations, is found to hold over six orders of
contact length scales, ten orders of normal load and in three vastly different contact conditions; (a) the probe penetrates
about 25% of the molecular backbone of a SAM; no substrate deformation, (b) the contact of the probe with the SAM is conformal
and the substrate is plastically deformed and (c) the molecule is dispersed in 5% (v/v) concentration in n-hexadecane to lubricate a pin-on-disc contact. 相似文献
23.
Nicholas Faust Robert W. Messler Subhash Khatri 《Journal of Electronic Materials》2001,30(10):1276-1286
Differences in the coefficients of thermal expansion (CTE) between silicon wafers and underlying copper electrodes have led
to the use of purely mechanical dry pressure contacts for primary electrical and thermal connections in high-power solid-state
electronic devices. These contacts are limited by their ability to dissipate I2R heat from within the device and by their thermal fatigue life. To increase heat dissipation and effectively deal with the
CTE mismatch, metallurgical bonding of the silicon to a specially-structured, strain-accommodating copper electrode has been
proposed. This study was intended to seek alternative methods for and demonstrate the feasibility of bonding Si to structured
Cu in high-power solid-state devices. Three different but fundamentally related fluxless approaches identified and preliminarily
assessed were: (1) conventional Sn−Ag eutectic solder; (2) a new, commercially-available active solder based on the Sn−Ag
eutectic; and (3) solid-liquid interdiffusion bonding using the Au−In system. Metallurgical joints were made with varying
quality levels (according to nonde-structive ultrasonic C-scan mapping, SEM, and electron microprobe) using each approach.
Mechanical shear testing resulted in cohesive failure within the Si or the filler alloys. The best approach, in which eutectic
Sn−Ag solder in pre-alloyed foil form was employed on Si and Cu substrates metallized (from the substrate outward) with Ti,
Ni and Au, exhibited joint thermal conduction 74% better than dry pressure contacts.
Formally an M.S. candidate at Rensselaer Polytechnic Institute, Troy, NY.
Professor of Materials Science and Engineering/Director of Materials Joining, advised Mr. Faust
sponsor of the development effort 相似文献
24.
Hyungoo Lee Cooper R. Mika B. Clayton D. Garg R. Gonzalez J.M. Vinson S.B. Khatri S. Hong Liang 《IEEE sensors journal》2007,7(12):1698-1702
We have developed a method using a polyvinylidene fluoride (PVDF) polymeric sensor to monitor the leg movements of cockroaches. The PVDF sensor was coated with gold as electrodes. It was attached to the leg of a roach. The voltage signals generated through bending directly correlate to the movement of the legs. It was found that the output voltage was a function of the degree of sensor bending caused by the movement of leg sclerites. An ex situ motorized linear stage generated similar results. 相似文献
25.
Effect of Footing Roughness on Lower Bound Nγ Values 总被引:1,自引:0,他引:1
The bearing capacity factor Nγ was computed for a strip footing by considering the variation of footing-soil interface friction angle (δ). The study follows a lower bound limit analysis in conjunction with finite elements and linear programming. The variation of Nγ with δ was obtained for different soil friction angles. The magnitude of Nγ increases significantly with the increase in δ. For δ = 0, the normal stress along the footing-soil interface was found to increase almost linearly with the increase in the distance from the footing edge. However, with the increase in δ, the location of the peak normal stress shifts gradually away from the center of the footing. The size of the plastic zone in relation to the footing width becomes gradually larger for greater values of δ. With respect to variation in δ, the obtained values of Nγ were found to be generally smaller than the results available in the literature. 相似文献
26.
Khatri Deepti Goyal Rahul Darad Akarsh Jain Akshat Rawat Samar Khan Alif Johnson Alan T. 《Clean Technologies and Environmental Policy》2019,21(7):1485-1498
Clean Technologies and Environmental Policy - The continual hike in environmental pollution from diesel engines has raised the concern of researchers to identify certain clean fuels. For this... 相似文献
27.
DIAGENETIC ALTERATIONS AND RESERVOIR QUALITY EVOLUTION OF LOWER CRETACEOUS FLUVIAL SANDSTONES: NUBIAN FORMATION,SIRT BASIN,NORTH‐CENTRAL LIBYA
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F. El‐Khatri M. A. K. El‐Ghali H. Mansurbeg S. Morad N. Ogle R. M. Kalin 《Journal of Petroleum Geology》2015,38(2):217-239
Lower Cretaceous meandering and braided fluvial sandstones of the Nubian Formation form some of the most important subsurface reservoir rocks in the Sirt Basin, north‐central Libya. Mineralogical, petrographical and geochemical analyses of sandstone samples from well BB6–59, Sarir oilfield, indicate that the meandering fluvial sandstones are fine‐ to very fine‐grained subarkosic arenites (av. Q91F5L4), and that braided fluvial sandstones are medium‐ to very coarse‐grained quartz arenites (av. Q96F3L1). The reservoir qualities of these sandstones were modified during both eodiagenesis (ca. <70°C; <2 km) and mesodiagenesis (ca. >70°C; >2 km). Reservoir quality evolution was controlled primarily by the dissolution and kaolinitization of feldspars, micas and mud intraclasts during eodiagenesis, and by the amount and thickness of grain‐coating clays, chemical compaction and quartz overgrowths during mesodiagenesis. However, dissolution and kaolinitization of feldspars, micas and mud intraclasts resulted in the creation of intercrystalline micro‐ and mouldic macro‐porosity and permeability during eodiagenesis, which were more widespread in braided fluvial than in meandering fluvial sandstones. This was because of the greater depositional porosity and permeability in the braided fluvial sandstones which enhanced percolation of meteoric waters. The development of only limited quartz overgrowths in the braided fluvial sandstones, in which quartz grains are coated by thick illite layers, retained high porosity and permeability (12–23% and 30–600 mD). By contrast, meandering fluvial sandstones underwent porosity loss as a result of quartz overgrowth development on quartz grains which lack or have thin and incomplete grain‐coating illite (2–15% and 0–0.1 mD). Further loss of porosity in the meandering fluvial sandstones occurred as a result of chemical compaction (pressure dissolution) induced by the occurrence of micas along grains contacts. Other diagenetic alterations, such as the growth of pyrite, siderite, dolomite/ankerite and albitization, had little impact on reservoir quality. The albitization of feldspars may have had minor positive influence on reservoir quality through the creation of intercrystalline micro‐porosity between albite crystals. The results of this study show that diagenetic modifications of the braided and meandering fluvial sandstones in the Nubian Formation, and resulting changes in reservoir quality, are closely linked to depositional porosity and permeability. They are also linked to the thickness of grain‐coating infiltrated clays, and to variations in detrital composition, particularly the amounts of mud intraclasts, feldspars and mica grains as well as climatic conditions. 相似文献
28.
Gil-López Cristina Guixeres Jaime Moghaddasi Masoud Khatri Jaikishan Marín-Morales Javier Alcañiz Mariano 《Virtual Reality》2023,27(3):1937-1966
Virtual Reality - The use of virtual reality (VR) technology in the context of retail is a significant trend in current consumer research, as it offers market researchers a unique opportunity to... 相似文献
29.
Sanju Khatri 《日用电器》2007,(3):14
在大量消费者和公司需求的支撑之下,欧洲/中东/非洲(EMEA)以42%的全球市场份额而超过了北美,在2006年第4季度成为全球正投出货量最大的地区。 相似文献
30.
Jayakumar N. Khatri S. P. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2007,15(3):276-285
In this paper, we describe a new low-leakage standard cell based application-specific integrated circuit (ASIC) design methodology. This design is based on the use of modified standard cells, designed to reduce leakage currents (by almost two orders of magnitude) in standby mode and also allow precise estimation of leakage current. For each cell in a standard cell library, two low-leakage variants of the cell are designed. If the inputs of a cell during the standby mode of operation are such that the output has a high value, we minimize the leakage in the pull-down network, and similarly we minimize leakage in the pull-up network if the output has a low value. In this manner, two low-leakage variants of each standard cell are obtained. While technology mapping a circuit, we determine the particular variant to utilize in each instance, so as to minimize leakage of the final mapped design. We have performed experiments to compare placed-and-routed area, leakage and delays of this new methodology against Multithreshold CMOS (MTCMOS) and a regular standard cell based design style. The results show that our new methodology (which we call the "HL" methodology) has better speed and area characteristics than MTCMOS implementations. The leakage current for HL designs can be dramatically lower than the worst-case leakage of MTCMOS based designs, and two orders of magnitude lower than the leakage of traditional standard cells. An ASIC design implemented in MTCMOS would require the use of separate power and ground supplies for latches and combinational logic, while our methodology does away with such a requirement. Another advantage of our methodology is that the leakage is precisely estimable, in contrast with MTCMOS. Our primary contribution in this paper is a new low leakage design style for static CMOS designs. In addition, we also discuss techniques to reduce leakage in dynamic (domino logic) designs 相似文献