OALib Journal期刊

ISSN: 2333-9721



匹配條件: “ Attia Boudjemline” ,找到相關結果約302條。
Electrochemical Engineering in the Core of the Dye-Sensitized Solar Cells (DSSCs)  [PDF]
Djamel Ghernaout, Attia Boudjemline, Noureddine Elboughdiri
Open Access Library Journal (OALib Journal) , 2020, DOI: 10.4236/oalib.1106178
Abstract: Dye-sensitized solar cells (DSSCs) are classed in the category of thin-film solar cells, which have been under thorough investigation during the last thirty years thanks to their low price, easy fabrication procedure, low toxicity and ease of generation. Even now, there are great efforts to substitute the present DSSC materials because of their elevated price, less abundance, and long-term stability. The performance of present DSSCs attains 12%, employing Ru(II) dyes via regulating material and structural features, which remains less than the performance given by first- and second-generation solar cells, i.e., other thin-film solar cells and Si-based solar cells which provide ~20% - 30% performance. This work focuses on the main findings of Sharma et al. [1] which presented an in-depth review on DSSC fabrication, running principle, fundamental issues (low efficiency, low scalability, and low stability), prospective efficient materials, and finally a brief insight to commercialization.
Studies of Tectonic Motion from Helwan-Satellite Laser Ranging Station  [PDF]
Gamal F. Attia
International Journal of Astronomy and Astrophysics (IJAA) , 2014, DOI: 10.4236/ijaa.2014.44055
Abstract: Satellite Laser Ranging (SLR) is a proven space geodetic technique with significant potential for important contributions to scientific studies of tectonic motion. Currently, SLR is the most accurate available technique to determine the geocentric position with a reported precision in the order of few millimeters. Data gathered through SLR together with “Short Arc” mathematical algorithm became a highly precise tool to detect, monitor and calculate recent crustal movements through repeated measurements of the baselines between some stations on different tectonic plates. In this paper, the Short Arc mathematical model introduced in a previous paper was used to calculate the length of the baseline between Helwan-SLR station and other four fixed SLR stations, placed on different plates. Application of this model with the data gathered through a 4 year time interval gave repeatable results with very high accuracy (in the order of 4 cm).
Interactive Effect of Forage Mixing Rates and Organic Fertilizers on the Yield and Nutritive Value of Berseem Clover (Trifolium alexandrinum L.) and Annual Ryegrass (Lolium multiflorum Lam.)  [PDF]
Heba Sabry Attia Salama
Agricultural Sciences (AS) , 2015, DOI: 10.4236/as.2015.64041

Berseem clover (Trifolium alexandrinum L.) is the main winter forage legume in Egypt. Despite that the yield and protein content of berseem clover are high, it is characterized by low dry matter content especially in the 1st cut. Intercropping berseem clover with forage grasses, especially annual ryegrass (Lolium multiflorum Lam.) is a recommended technique to produce higher forage yield with better balanced nutritional quality. However, little is known about the performance of these proposed mixtures under the arising organic farming system in Egypt. Organic farming and the application of organic fertilizers (compost and poultry manure) are receiving increased attention in the last few years. Thus, the current study was carried out on the winter season of two successive years (2012 and 2013) in the experimental station of SEKEM organic farm, Egypt. Main aim was to investigate the variation in 1st cut forage yield and nutritive value of berseem clover and annual ryegrass, grown in pure stands and with three mixing rates, under three organic fertilization regimes (compost, poultry litter, and no fertilization). Nutritive value was judged through investigating the crude protein (CP), total carbohydrates (TC), and fiber fractions (NDF, ADF, and ADL). Results revealed significant two-way interaction between the forage treatments and the fertilization regimes for all the studied parameters. In general, mixing berseem clover with annual ryegrass, fertilized by compost or poultry litter resulted in significantly higher forage yield, dry matter content, and balanced CP, TC, and fiber fractions, compared to the pure stands.

The Impact of Credit Risk Management in Financial Market Indicators—Analytical Study in the Iraqi Market for Securities  [PDF]
Mahdi Attia Jubouri
Journal of Financial Risk Management (JFRM) , 2018, DOI: 10.4236/jfrm.2018.73017
Abstract: The objective of this study was to determine the relationship between credit risk management and financial market indicators. The study problem is summarized as follows: Do credit risk management indicators affect financial market indicators in private banks? The study relied on two basic hypotheses: the existence of a significant and significant correlation and effect relationship between credit risk management and financial market indicators. The sample of the study was a sample of private commercial banks in Iraq consisting of eight banks. The required information was obtained through the annual reports of the sample banks, as well as through the official publications of the Iraqi Stock Exchange for the period (2007-2016). The study used the program (Microsoft Excel 2013) in addition to the statistical methods found in the statistical program (SPSS V.23), and the importance of the study that it emerged out of the intellectual basis of the nature of the variables of the study based on the practical reality of the variables and the ability of these variables to achieve the goals. The study reached a number of conclusions, the most prominent of which was the existence of a difference between the banks in the relationship of correlation and impact between the variables of the study, and the study also reached a set of recommendations and suggestions.
Influence of surface treatment and cyclic loading on the durability of repaired all-ceramic crowns
Attia, Ahmed;
Journal of Applied Oral Science , 2010, DOI: 10.1590/S1678-77572010000200015
Abstract: objective: this study investigated the durability of repaired all-ceramic crowns after cyclic loading. material and methods: eighty in-ceram zirconia crowns were fabricated to restore prepared maxillary premolars. resin cement was used for cementation of crowns. palatal cusps were removed to simulate fracture of veneering porcelain and divided into 4 groups (n = 20). fracture site was treated before repair as follows: roughening with diamond bur, (db); air abrasion using 50 μm al2o3, (aa) and silica coating using cojet system followed by silane application, (sc). control group (cg) 20 specimens were left without fracture. palatal cusps were repaired using composite resin. specimens were stored in water bath at 37oc for one week. ten specimens of each group were subjected to cyclic loading. fracture load (n) was recorded for each specimen using a universal testing machine. two-way analysis of variance (anova) and tukey honestly significant difference (hsd) test (a=.05) were used for statistical analysis. results: there was statistically significant difference between control and tested groups, (p<0.001). post hoc analysis with the tukey hsd test showed that cyclic loading fatigue significantly decreased means fracture load of control and test groups as follows (cg, 950.4±62.6 / 872.3±87.4, p = 0.0004), (db, 624.2 ±38 / 425.5± 31.7, p <.001), (aa, 711.5 ±15.5 / 490 ± 25.2, p <0.001) and (sc, 788.7 ± 18.1 / 610.2 ± 25.2, p <.001), while silica coating and silane application significantly increased fracture load of repaired crowns (p<0.05). conclusion: repair of fractured in-ceram zirconia crowns after chairside treatment of the fracture site by silica coating and silane application could improve longevity of repaired in-ceram zirconia crowns.
Bond strength of three luting agents to zirconia ceramic - influence of surface treatment and thermocycling
Attia, Ahmed;
Journal of Applied Oral Science , 2011, DOI: 10.1590/S1678-77572011005000015
Abstract: objective: this in vitro study aimed to evaluate the influence of different surface treatments, 3 luting agents and thermocycling on microtensile bond strength (μtbs) to zirconia ceramic. material and methods: a total of 18 blocks (5x5x4 mm) were fabricated from zirconia ceramic (ice zirkonia) and duplicated into composite blocks (alphadent). ceramic blocks were divided into 3 groups (n=6) according to the following surface treatments: airborne-particle abrasion (aa), silica-coating, (sc) (cojet) and silica coating followed by silane application (scsi) (espe sil). each group was divided into 3 subgroups (n=2) according to the 3 luting agents used. resin-modified glass-ionomer cement (rmgic, ketac cem plus), self-adhesive resin cement (un, relyx unicem) and adhesive resin cement (ml, multilink automix) were used for bonding composite and zirconia blocks. each bonding assembly was cut into microbars (10 mm long and 1±0.1 mm2). seven specimens of each subgroup were stored in water bath at 37oc for 1 week. the other 7 specimens were stored in water bath at 37oc for 30 days then thermocycled (tc) for 7,500 cycles. μtbs values were recorded for each specimen using a universal testing machine. statistical analyses were performed using a 3-way anova model followed by serial 1-way anovas. comparison of means was performed with tukey's hsd test at (α=0.05). results: μtbs ranged from 16.8 to 31.8 mpa after 1 week and from 7.3 to 16.4 mpa after 30 days of storage in water and thermocycling. artificial aging significantly decreased μtbs (p<0.05). considering surface treatment, scsi significantly increased μtbs (p<0.05) compared to sc and aa. resin cements (un and ml) demonstrated significantly higher μtbs (p<0.05) compared to rmgic cement. conclusions: silica coating followed by silane application together with adhesive resin cements significantly increased μtbs, while thermocycling significantly decreased μtbs.
Réflexion sur l’origine du processus de segmentation du marche du travail
Attia Nicole
Panoeconomicus , 2006, DOI: 10.2298/pan0601019a
Abstract: (francuski) Ce travail propose une réflexion sur l'origine du processus de segmentation du marché du travail par rapport à l'entreprise. Se situe-t-elle au sein même de l'entreprise ou en amont, c'est à dire entre les entreprises? Cela revient à se demander si on peut avoir une approche microéconomique ou macroéconomique de la segmentation et, à s'interroger sur le r le réel tenu par les firmes dans le processus. Déterminant pour la théorie, ce r le est à repenser selon la réponse apportée à notre question.
Signes et traces dans l’ uvre poétique de Günter Eich
Sandie Attia
Trajectoires , 2010,
Abstract: Cette thèse porte sur les catégories signe (Zeichen) et trace (Spur) dans l’ uvre poétique et les déclarations poétologiques de Günter Eich (1907-1972). Signes naturels, linguistiques, traces biographiques et intertextuelles, relevé de stigmates historiques (Spurensicherung) imprègnent l’ uvre de Eich tant sous la forme d’images poétiques que de concepts poétologiques. Complémentaires ou opposés, ils éclairent le parcours complexe du poète, du déchiffrement des signes naturels au souh...
Taha Attia
Annals of Saudi Medicine , 2010,
Taha Attia
Annals of Saudi Medicine , 2010,

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