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61.
62.
Amal Amin Moshera Samy Sameh Hosam Abd El-Alim Abd El Gawad Rabia Magdy M. H. Ayoub 《国际聚合物材料杂志》2018,67(16):942-950
Vitamin C (Vit.C)-entrapped polycaprolactone (PCL) nanoparticles (Vit.C–PCNs) were prepared by encapsulation of Vit.C into PCL-based nanoparticles (PCNs) which were prepared using double emulsion method with two steps. First, the inner aqueous phase (W1) was added to dichloromethane solution containing PCL with homogenization to form primary emulsion (W1/O) which was emulsified with the outer aqueous phase (W2) containing polyvinyl alcohol as stabilizer to attain the double emulsion (W1/O/W2). Versatile parameters were investigated to reach to the most successful formulation for Vit.C–PCNs, such as time, effect of speed of homogenization on drug encapsulation efficiency, etc. 相似文献
63.
Dempsey PG Ayoub MM Bernard TM Endsley MR Karwowski W Lin CJ Smith JL 《Applied ergonomics》1996,27(5):303-313
A field study was conducted to compare four satchels designed for the purposes of manually carrying and delivering mail. The satchels differed primarily in the presence/absence of a waist belt, the number and design of the shoulder strap(s) and the number of pouches. The evaluation consisted of questionnaires and interviews of slightly more than 300 letter carriers employed by the United States Postal Service. The questionnaires focused on 10 main areas of interest; ease of adjustability and handling, comfort, suitability and durability of materials, anthropometric applications, impact on other activities, ease of motion in retrieving mail, ease of motion in carrying the satchel, versatility of use in diverse climates, protection of mail from damage due to rain and snow, and defense against dog attacks. The primary conclusion was that the satchel with two shoulder straps and two pouches, which results in more symmetric loading than the other satchels, is the most desirable of the satchels tested. However, there are problems with the satchel that need to be addressed, such as concerns about the use of the satchel for defense from dog attacks. 相似文献
64.
Ayoub Tamim Khalid Minaoui Khalid Daoudi Hussein Yahia Abderrahman Atillah Salma El Fellah 《International journal of remote sensing》2019,40(7):2648-2666
An efficient unsupervised method is developed for automatic segmentation of the area covered by upwelling waters in the coastal ocean of Morocco using the Sea Surface Temperature (SST) satellite images. The proposed approach first uses the two popular unsupervised clustering techniques, k-means and fuzzy c-means (FCM), to provide different possible classifications to each SST image. Then several cluster validity indices are combined in order to determine the optimal number of clusters, followed by a cluster fusion scheme, which merges consecutive clusters to produce a first segmentation of upwelling area. The region-growing algorithm is then used to filter noisy residuals and to extract the final upwelling region. The performance of our algorithm is compared to a popular algorithm used to detect upwelling regions and is validated by an oceanographer over a database of 92 SST images covering each week of the years 2006 and 2007. The results show that our proposed method outperforms the latter algorithm, in terms of segmentation accuracy and computational efficiency. 相似文献
65.
Raphael Berger Yigal Lilach Yousif Ayoub Micha Asscher 《Israel journal of chemistry》2005,45(1-2):97-109
The photochemistry of molecules constrained within a confining environment on surfaces has been studied. Orientation of methyl bromide could be controlled methyl down or up by varying the pre-adsorbed oxygen coverage due to electrostatic interactions on Ru(001) under UHV conditions. Irradiation of the coadsorption system at 193 nm has shown that the resulting photochemical activity is sensitive to the molecular orientation. Photodesorption and dissociation cross sections were 1.0·10−19 cm−2 for methyl-down and 3.0·10−19 cm−2 for the methyl-up configurations. This observation represents the first report of the steric effect in electron-molecule interaction due to the dissociative electron attachment mechanism of photochemical processes on surfaces. A second system of CO2 molecules caged within ice has also been studied. Here the trapped carbon dioxide molecules cannot leave the surface at their normal desorption temperature near 100 K, but are explosively desorbing at the onset of ice evaporation near 165 K. Upon UV irradiation, enhanced dissociation to adsorbed CO and oxygen is recorded. In addition, a new reactivity channel is observed to form H2CO, tentatively identified as formaldehyde. The relevance of photochemistry of caged molecules within ice to interstellar hydrocarbon formation as a possible route for the origin of life is discussed. 相似文献
66.
K‐nearest neighbors (KNN) search in a high‐dimensional vector space is an important paradigm for a variety of applications. Despite the continuous efforts in the past years, algorithms to find the exact KNN answer set at high dimensions are outperformed by a linear scan method. In this paper, we propose a technique to find the exact KNN image objects to a given query object. First, the proposed technique clusters the images using a self‐organizing map algorithm and then it projects the found clusters into points in a linear space based on the distances between each cluster and a selected reference point. These projected points are then organized in a simple, compact, and yet fast index structure called array‐index. Unlike most indexes that support KNN search, the array‐index requires a storage space that is linear in the number of projected points. The experiments show that the proposed technique is more efficient and robust to dimensionality as compared to other well‐known techniques because of its simplicity and compactness. © 2011 Wiley Periodicals, Inc. 相似文献
67.
Kamal Ayoub Momani 《仪器科学与技术》2013,41(5):587-605
Abstract Bottled water brands, consisting of both local and imported types, collected from Doha city, Qatar, were evaluated for their suitability for human consumption. Water quality constituents that were analyzed include trihalomethanes (THM) by GC‐ECD, turbidity, TDS, total hardness, total alkalinity, pH, EC, major anions by IC, and major cations and trace metals by ICP‐MS. The data obtained were compared with the WHO and the USEPA drinking water standards. As, Se, Ba, and Cu were undetected in all water samples. The levels of potential toxic metals in the studied brands were generally low, except for three brands that had Cd and Pb which exceeded the WHO limits. Fluoride was generally present in all bottled water brands at levels less than the lower optimum level. The reported data for pH, turbidity, TDS, EC, alkalinity, hardness, major anions, and major cations were generally in compliance with the WHO and the USEPA standards, with exception of five brands, where the levels of TDS, EC, F, and NO3 exceeded the WHO recommended limits. Also, it was found that the concentrations of NO3 F, Fe, Cr, Zn, and Pb were higher in the local brands. The levels of Cd, Mn, Ca, Mg, EC, alkalinity, SO4, TDS, THM, and hardness were higher in the domestic brands, when compared to the imported ones. The levels of Cl, pH, turbidity, and Na in the domestic brands were comparable to imported ones. Three THM were found in 29% of water samples with three brands having CHCl2Br and CHCl3 levels exceeding the WHO standards. Comparison of the results of this study with the reported label values of both domestic and imported bottled water showed good agreement with pH and K values, but significant variation for Ca, Mg, F, NO3, and SO4 in the imported brands and relatively low variation in the domestic brands. The results of chemical analysis of SRM 1460, trace elements in water, were generally in good agreement with NIST certified values. 相似文献
68.
Khurshid Hafiz Fatima Farran Hani Allawnha Mohamad Ayoub Mohammad El‐Chafei 《The International journal of environmental studies》2013,70(4):433-443
Idling the engine of heavy‐duty truck is the only way a driver can control the temperature in the cab/sleeper and have power for auxiliary devices when the truck is parked. It is an inefficient and noisy process that wastes thousands of litres of fuel per year while standing stationary in a parking lot. Almost all heavy‐duty trucks idle about 20–40% of the time when the engine is running, depending on season, geographic location and trucking operation. This extensive engine idling has many disadvantages, including pollutant emissions, noise pollution, unnecessary fuel and maintenance costs, and driver discomfort. This paper discusses the problems related to truck idling and proposes an auxiliary power generation unit that can significantly reduce the fuel consumption, cut the costs, enhance engine life and reduce pollution. A control methodology is presented to regulate the output voltage of the auxiliary power unit under variable load conditions. 相似文献
69.
Friction Stir Welding of Low-Carbon AISI 1006 Steel: Room and High-Temperature Mechanical Properties
Vasanth C. Shunmugasamy Bilal Mansoor Georges Ayoub Ramsey Hamade 《Journal of Materials Engineering and Performance》2018,27(4):1673-1684
Friction stir welding (FSW) is an ecologically benign solid-state joining process. In this work, FSW of low-carbon AISI 1006 steel was carried out to study the microstructure and mechanical properties of the resulting joints at both room temperature (RT) and 200 °C. In the parameter space investigated here, a rotational tool speed and translation feed combination of 1200 rpm and 60 mm/min produced a defect-free weld with balanced mechanical properties and a superior Vickers microhardness profile compared to all other conditions and to base metal (BM). At faster translation feeds (100 and 150 mm/min), wormhole defects were observed in the weld microstructure and were attributed to higher strain rate experienced by the weld zone. Under tensile loading, welded material exhibited yield strength that was up to 86 and 91% of the BM at RT and 200 °C, respectively. On the other hand, tensile strength of welded material was nearly similar to that of the base metal at both RT and 200 °C. However, at both temperatures the tensile ductility of the welded joints was observed to be significantly lower than the BM. Annealing of the 1200 rpm and 60 mm/min FSW specimen resulted in tensile strength of 102% compared to base material and 47% increase in the strain at failure compared to the as-welded specimen. The Charpy impact values revealed up to 62 and 53% increase in the specific impact energy for the 1200 rpm and 60 mm/min welded joints as compared with the BM. 相似文献
70.
Fahd Saeed Alakbari Mysara Eissa Mohyaldinn Mohammed Abdalla Ayoub Ali Samer Muhsan Said Jadid Abdulkadir Ibnelwaleed A. Hussein Abdullah Abduljabbar Salih 《加拿大化工杂志》2023,101(5):2493-2509
Sand production is a critical issue in petroleum wells. The critical total drawdown (CTD) is an essential indicator of the onset of sand production. Although some models are available for CTD prediction, most of them are proven to lack accuracy or use commercial software. Furthermore, the previous correlations have not studied the trend analysis to verify the correct relationships between the parameters. Therefore, this study aims to build accurate and robust models for predicting CTD using response surface methodology (RSM) and support vector machine (SVM). The RSM is utilized to obtain the equation without using any software. The SVM model is an alternative method to predict the CTD with higher accuracy. This study used 23 datasets to develop the proposed models. The CTD is a strong function of the total vertical depth, cohesive strength, effective overburden vertical stress, and transit time with correlation coefficients (R) of 0.968, 0.963, 0.918, and −0.813. Different statistical methods, that is, analysis of variance (ANOVA), F-statistics test, fit statistics, and diagnostics plots, have shown that the RSM correlation has high accuracy and is more robust than correlations reported in the literature. Moreover, trend analysis has proven that the proposed models ideally follow the correct trend. The RSM correlation decreased the average absolute percent relative error (AAPRE) by 12.7% compared to all published correlations' AAPRE of 22.6%–30.4%. The SVM model has shown the lowest AAPRE of 6.1%, with the highest R of 0.995. The effects of all independent variables on the CTD are displayed in three-dimensional plots and showed significant interactions. 相似文献