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61.
S. S. Fouad E. A. A. El-Shazly M. R. Balboul S. A. Fayek M. S. El-Bana 《Journal of Materials Science: Materials in Electronics》2006,17(3):193-198
The optical properties of As30Se70-xSnx with (x = 0, 1, 2 and 3 at Sn %) thin films have been investigated. The films used in these studies were thermally evaporated. The
structural characterization revealed that the as-deposited films were amorphous in nature. The spectral and optical parameters
have been investigated using spectrophotometric measurements of transmittance in the wavelength range (200–1100 nm). The optical
constants were determined from the interference maxima and minima using the Swanepole method. The dispersion of the refractive
index is discussed in terms of the single-oscillator Wemple-Didomenico model. The optical-absorption edge and the optical
band gap are calculated from the absorption coefficient values using the non direct transition model proposed by Tauc’s extrapolation
procedure. The relation between the optical gap and chemical composition in As-Se-Sn glassy system is discussed in terms of
the average heat of atomization Hs and the average coordination number Nc. 相似文献
62.
Feruglio S. Fouad Hanna V. Alquie G. Vasilescu G. 《IEEE transactions on instrumentation and measurement》2006,55(6):1892-1903
In this paper, analytical expressions of dark currents and equivalent noise generators of a CMOS color image sensor are presented, and the signal-to-noise ratio (SNR) at both outputs is evaluated. Static measurements and simulations on Austria Micro Systems 0.35-mum CMOS test structures yield guidelines to increase the SNR of the buried double junction photodetector 相似文献
63.
A. M. Farid S. S. Fouad A. H. Ammar 《Journal of Materials Science: Materials in Electronics》2005,16(2):97-101
High purity glasses with an average coordination number Nc in the GexSb40–xSe60 ternary system between 2.4 and 2.7, were prepared under vacuum with x = 0, 10, 20 and 30. X-ray diffraction (XRD) as, well as the Differential Scanning Calorimetry (DSC) studies were carried out to identify the amorphous and polycrystalline structure for the Ge-Sb-Se system. The dependence of properties such as the mean atomic volume Va, the glass transition temperature Tg and the number of topological constraints Ncon were studied as a function of Nc, in the light of recent model proposed for covalent random network. The occurrence of this dependence in addition to those due to topological effects leads to the conclusion that the effects of chemical ordering and the effect, which have topological origin, coexist in this system. To understand the effect of Nc on the glass-forming capability, the number of lone-pair electrons, (Ncs–Nc)/2, and the efficiency of the structural modification were calculated and discussed in relation to topological consideration. This then renders support to Phillipstheoretical model. 相似文献
64.
65.
Fouad Al Katrib Gerard Chambat Jean-Paul Joseleau 《Journal of the science of food and agriculture》1988,43(4):309-317
Enzymic saccharification of wheat straw in the absence of any pretreatment was only about 20 %. Acid hydrolysis did not improve the overall cellulose enzymic breakdown, nor did pretreatment by flash autohydrolysis under pressure or sodium chlorite delignification. When wheat straw was treated with N-methyl-morpholine-N-oxide (MMNO) at J20°C for 20–30 min, this treatment and subsequent enzymic hydrolysis produced carbohydrate conversion of 73%. Similar results could be obtained by treating straw with 0·1 M sodium hydroxide. When MMNO treatment was combined with any other pretreatment, the saccharification yield was greatly enhanced. Nearly quantitative conversion was obtained by swelling straw in 0·1 M sodium hydroxide followed by MMNO treatment. The results show that lignin content of plant material does not represent the limiting factor to enzymic saccharification. 相似文献
66.
CE Lewis V George M Fouad V Porter D Bowen N Urban 《Canadian Metallurgical Quarterly》1998,19(5):461-476
The Women's Health Trial:Feasibility Study in Minority Populations (WHT:FSMP) examined the feasibility of recruiting postmenopausal women from a broad range of racial and socioeconomic backgrounds into a primary prevention trial requiring marked reductions in dietary fat. Postmenopausal women aged 50-79 yr who had no history of cardiovascular disease or cancer and who consumed 36% or more total energy from fat qualified to participate. We randomized the women into dietary intervention (60%) or control (40%) groups; we aimed to randomize 750 women in 18 months in each of the three clinical centers. All centers achieved goals for randomization based on ethnicity, and two centers exceeded overall recruitment goals. The greatest source of randomized participants was mass mailing, followed by items in the media, referrals, and community outreach. Recruitment yields were generally similar for the ethnic groups but lower for less-educated participants. The experience of WHT:FSMP indicates that postmenopausal women from the African-American, Hispanic, and non-Hispanic white communities can be recruited into dietary intervention studies for the prevention of disease. 相似文献
67.
Virginia P. Sisiopiku Aymeric Rousseau Fouad H. Fouad Robert W. Peters 《Canadian Metallurgical Quarterly》2006,132(6):568-574
This study analyzed candidate hydrogen-fueled vehicles for near and long-term use associated with their efficiency, performance, and emissions. Various types of hydrogen-fueled vehicles were assessed using Argonne National Laboratory's Powertrain System Analysis Toolkit vehicle simulation model. These include hythane- and hydrogen-fueled internal combustion engines (ICEs), hydrogen-fueled hybrid electric propulsion, and direct hydrogen fuel cells. Vehicle sizes and configurations, consistent with the available component models/data, were simulated to compare efficiency and emissions with baseline conventional vehicles. The simulations provided salient information on the vehicle characteristics, performance, and efficiency, as functions of operating conditions on standard driving cycles. It was found that substantial gains in fuel economy can be achieved through hybridization both for conventional and fuel cell vehicles. When hybridized, hydrogen ICE configurations achieve similar fuel economy to gasoline counterparts. The results also confirm that ICE hybrid electric vehicles (HEV) achieve higher fuel economy than fuel cell configurations and comparable results with fuel cell HEV. Comparison of efficiency results for various driving cycles further indicates that cycles with low power demand are most suited for hybrid operations. 相似文献
68.
The sludge production and settleability have been estimated experimentally in a completely mixed biofilm-activated sludge reactor (hybrid reactor). A steady-state hybrid reactor was run at different stages of suspended biomass concentration (X) under constant values of influent substrate concentration (So) and hydraulic retention time (HRT). The values of X were gradually decreased in these stages until the system completely washed out of the suspended biomass and converted to pure biofilm reactor. As a result, the role of biofilm in the treatment gradually increased with an increase in the effluent substrate concentration (S). The experiment was supported by a mathematical expression for describing the sludge yield in the system under the previous conditions. The experimental and theoretical studies in the present work reveal that there is a critical phase of the hybrid system at which the system produces a high rate of excess sludge. That critical phase is found at a specific ratio between the suspended and the attached growth. Avoiding that critical phase enables the sludge production in the hybrid reactor to be reduced and optimized. Further, the minimum sludge production was found when the biofilm is theoretically inactive for chemical oxygen demand (COD) removal (S相似文献
69.
Allen Hope Geoffrey Fouad Yelena Granovskaya 《International journal of remote sensing》2013,34(13):4852-4864
Indigenous forests in South Africa cover less than 0.5% of the total land area but are a valued resource under threat from fragmentation, fires, exploitation, and climate change. The largest indigenous forest complex is located along the southern coast of the Western Cape Province. This complex is made up of sub-forests distinguished by different structural and edaphoclimatic attributes. It has been hypothesized that these sub-forests exhibit different resistance to stressors, such as drought. A time series of MODIS 250 m enhanced vegetation index (EVI) data were used to characterize the foliage condition of the three distinctive sub-forests before, during, and after a severe drought in 2009. The goal was to determine how these sub-forests responded to this disturbance. EVI anomalies for the drought and post-drought periods were calculated using annual median EVI values, since removal of outliers based on quality control flags that accompany the MODIS products or noise-filtering techniques proved to be ineffective. Results of the study indicated that pre-drought foliage density EVI was not controlled by differences in water availability, but may have been due to other edaphoclimatic or structural attributes. Maximum foliage loss occurred one year after the driest year, indicating the cumulative effects of drought stress on forest production and retention of foliage. The hypothesized stress resistance capacity of the three sub-forests was found to correspond to their rate of post-drought recovery. There is a need to tie these satellite observations of forest drought response to ground observations of forest condition, growth, and specific site attributes. 相似文献
70.
Ali Fouad Keith Phalp John Mathenge Kanyaru Sheridan Jeary 《Software Quality Journal》2011,19(2):411-430
Model-Driven Architecture (MDA) brings benefits to software development, among them the potential for connecting software
models with the business domain. This paper focuses on the upstream or Computation-Independent Model (CIM) phase of MDA. Our contention is that, whilst there are many models and notations available
within the CIM phase, those that are currently popular and supported by the Object Management Group (OMG) may not be the most
useful notations for business analysts nor sufficient to fully support software requirements and specification. Therefore,
with specific emphasis on the value of the Business Process Modelling Notation (BPMN) for business analysts, this paper provides
an example of a typical CIM approach before describing an approach that incorporates specific requirements techniques. A framework
extension to MDA is then introduced, which embeds requirements and specification within the CIM, thus further enhancing the
utility of MDA by providing a more complete method for business analysis. 相似文献