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Search Results: 1 - 10 of 721832 matches for " M. A. El-Yakoubi "
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Measurement of Strange Quark Contributions to the Vector Form Factors of the Proton at Q**2=0.22 (GeV/c)**2
S. Baunack,K. Aulenbacher,D. Balaguer Ríos,L. Capozza,J. Diefenbach,B. Gl?ser,D. v. Harrach,Y. Imai,E. M. Kabu?,R. Kothe,J. H. Lee,H. Merkel,M. C. Mora Espí,U. Müller,E. Schilling,G. Stephan,C. Weinrich,J. Arvieux,M. A. El-Yakoubi,R. Kunne,F. E. Maas,M. Morlet,S. Ong,J. van de Wiele,S. Kowalski,Y. Prok,S. Taylor
Physics , 2009, DOI: 10.1103/PhysRevLett.102.151803
Abstract: A new measurement of the parity violating asymmetry in elastic electron scattering on hydrogen at backward angles and at a four momentum transfer of Q^2=0.22 (GeV/c)^2 is reported here. The measured asymmetry is A_LR=(-17.23 +- 0.82_stat +-0.89_syst) ppm. The Standard Model prediction assuming no strangeness is A_0=(-15.87 +- 1.22) ppm. In combination with previous results from measurements at forward angles, it it possible to disentangle for the first time the strange electric and magnetic form factors at this momentum transfer, G_E^s(0.22)=0.050 +- 0.038 +- 0.019 and G_M^s(0.22)=-0.14 +- 0.11 +- 0.11.
Evidence for Strange Quark Contributions to the Nucleon's Form Factors at $Q^2$ = 0.108 (GeV/c)$^2$
F. E. Maas,K. Aulenbacher,S. Baunack,L. Capozza,J. Diefenbach,B. Gl?ser,T. Hammel,D. von Harrach,Y. Imai,E. -M. Kabu?,R. Kothe,J. H. Lee,A. Lorente,E. Schilling,D. Schwaab,M. Sikora,G. Stephan,G. Weber,C. Weinrich,I. Altarev,J. Arvieux,M. El-Yakoubi,R. Frascaria,R. Kunne,M. Morlet,S. Ong,J. van de Wiele,S. Kowalski,B. Plaster,R. Suleiman,S. Taylor
Physics , 2004, DOI: 10.1103/PhysRevLett.94.152001
Abstract: We report on a measurement of the parity violating asymmetry in the elastic scattering of polarized electrons off unpolarized protons with the A4 apparatus at MAMI in Mainz at a four momentum transfer value of $Q^2$ = \Qsquare (GeV/c)$^2$ and at a forward electron scattering angle of 30$^\circ < \theta_e < 40^\circ$. The measured asymmetry is $A_{LR}(\vec{e}p)$ = (\Aphys $\pm$ \Deltastat$_{stat}$ $\pm$ \Deltasyst$_{syst}$) $\times$ 10$^{-6}$. The expectation from the Standard Model assuming no strangeness contribution to the vector current is A$_0$ = (\Azero $\pm$ \DeltaAzero) $\times$ 10$^{-6}$. We have improved the statistical accuracy by a factor of 3 as compared to our previous measurements at a higher $Q^2$. We have extracted the strangeness contribution to the electromagnetic form factors from our data to be $G_E^s$ + \FakGMs $G_M^s$ = \GEsGMs $\pm $ \DeltaGEsGMs at $Q^2$ = \Qsquare (GeV/c)$^2$. As in our previous measurement at higher momentum transfer for $G_E^s$ + 0.230 $G_M^s$, we again find the value for $G_E^s$ + \FakGMs $G_M^s$ to be positive, this time at an improved significance level of 2 $\sigma$.
Isolation, Biochemical Characterization and DNA Identification of Yogurt Starters Streptococcus thermophilus & Lactobacillus delbrueckii ssp. bulgaricus in Gaza Strip  [PDF]
Kamal E. M. El Kahlout, Ismail M. El Quqa, Mahmoud W. El Hindi, Tarek A. El Bashiti
Advances in Microbiology (AiM) , 2018, DOI: 10.4236/aim.2018.812068
Abstract: Background: Milk is a healthy human nutrient, which is fermented to yogurt by lactic acid bacteria, mainly Streptococcus salivarius ssp, thermophilus and Lactobacillus. delbrueckii ssp. bulgaricus. This study aimed to isolate thermophilic starter bacteria from homemade yogurt made in Gaza Strip. The study sought to define both the biochemical and molecular characteristics of the isolated bacteria. Results: Three of the isolates were identified as Streptococcus thermophiles while two isolates were recognized as Lactobacillus delbrueckii ssp. bulgaricus. All five identified isolates showed worthy acidification capacity. Based on these characters, strains were applied for making yogurt either as single pure cultures or as mixed cultures. When using mixed cultures from S. thermophiles and L. bulgaricus, all tested combinations showed positive results. Conclusion: Isolated strains showed remarkable biotechnological characters. The isolates are expected to stimulate and improve quality of the yogurt when they are used as mixed starter cultures.
Geochemical Siliceous and Silicified Facies of Phosphate Series of Ouled Abdoun Basin (Morocco)  [PDF]
H. El Haddi, A. Benbouziane, M. Mouflih
Open Journal of Geology (OJG) , 2014, DOI: 10.4236/ojg.2014.47022
Abstract:

Syn-sedimentary post-diagenetic phenomena are remarkable in Moroccan phosphates. Indeed they are reference deposits for geological study, where important interests are given of determination and identification of these geochemical phenomena. Silicification is one of the phenomena that we have studied to determine the diagenetic processes that control the new-formation of silica in phosphate series of Ouled Abdoun. This study was performed on deposit EL Halassa, which belongs to the Ouled Abdoun Basin; they spread out the Maastrichtian to Lutetian. At first, petrographic approach was applied on different terms composing the phosphate series. In a second step, a geochemical approach on the same silica and silicified facies of phosphate series Ouled Abdoun Basin for characterizing silicification deduced the probable links between this diagenetic phenomenon and facies and forms’ affect. Ten major trace elements were measured. According to the phases’ petrographic relationship, the results were presented and discussed: silicate phase, the carbonate phase and clay phase.

On the Real Einstein Beauty E = Kmc2  [PDF]
A. J. Babchin, M. S. El Naschie
World Journal of Condensed Matter Physics (WJCMP) , 2016, DOI: 10.4236/wjcmp.2016.61001
Abstract: The paper suggests that E = mc2 may be open to misinterpretation and that in this form it is not what Einstein advanced first. It is further suggested to return to the slightly less compact formula E = Kmc2 where a < K < 1 which has the merit of accounting for the measured ordinary energy density of the cosmos (K = 1/22) and the conjectured missing dark energy density of the universe (K = 21/22) from the view point of economical notation.
Artificial Neural Networks Based Integrated Predictive Modelling of Quality Characteristics in CNC Turning of Cantilever Bars  [PDF]
D. M. Davakan, A. El Ouafi
World Journal of Mechanics (WJM) , 2017, DOI: 10.4236/wjm.2017.75013
Abstract: The objective of this study is to develop an effective approach for product quality prediction in Computer Numerical Control turning of cantilever bars. A systematic predictive modelling procedure based on experimental investigations, neural network modelling and various statistical analysis tools is designed to produce the most accurate, practical and cost-effective prediction model. The modeling procedure begins by exploring the relationships between cutting parameters known to have an influence on quality characteristics of machined parts, such as dimensional errors, form errors and surface roughness, as well as their sensitivity to the process conditions. Based on these explorations and using numerous statistical tools, the most relevant variables to include in the prediction model are identified and fused using several artificial neural network architectures. An application on CNC turning of cantilever bars demonstrates that the proposed modeling procedure can be effectively and advantageously applied to quality characteristics prediction due to its simplicity, accuracy and efficiency. The experimental validation reveals that the resulting prediction model can correctly predict the quality characteristics of machined parts under variable machining conditions.
Sentinel-1 Radar Data Assessment to Estimate Crop Water Stress  [PDF]
M. A. El-Shirbeny, K. Abutaleb
World Journal of Engineering and Technology (WJET) , 2017, DOI: 10.4236/wjet.2017.52B006
Abstract:
Water is an important component in agricultural production for both yield quantity and quality. Although all weather conditions are driving factors in the agricultural sector, the precipitation in rainfed agriculture is the most limiting weather parameter. Water deficit may occur continuously over the total growing period or during any particular growth stage of the crop. Optical remote sensing is very useful but, in cloudy days it becomes useless. Radar penetrates the cloud and collects information through the backscattering data. Normalized Difference Vegetation Index (NDVI) was extracted from Landsat 8 satellite data and used to calculate Crop Coefficient (Kc). The FAO-Penman-Monteith equation was used to calculate reference evapotranspiration (ETo). NDVI and Land Surface Temperature (LST) were calculated from satellite data and integrated with air temperature measurements to estimate Crop Water Stress Index (CWSI). Then, both CWSI and potential crop evapotranspiration (ETc) were used to calculate actual evapotranspiration (ETa). Sentinel-1 radar data were calibrated using SNAP software. The relation between backscattering (dB) and CWSI was an inverse relationship and R2 was as high as 0.82.
Some Factors Affecting the Production of Carotenoids by Rhodotorula glutinis var. glutinis  [PDF]
Amr A. El-Banna, Amal M. Abd El-Razek, Ahmed R. El-Mahdy
Food and Nutrition Sciences (FNS) , 2012, DOI: 10.4236/fns.2012.31011
Abstract: A new yeast strain isolated from pin cushion flower (Scabiosa atropurpura) in our laboratory was selected from 200 yeast isolates as carotenoids producer and identified as Rhodotorula glutinis var. glutinis. The selected isolate was grown in synthetic medium to study the effect of carbon to nitrogen ratio, sources of nitrogen and carbon, mineral salts and incubation temperature on carotenoids production. The results indicated the following optimal conditions: carbon to nitrogen ratio of 5, ammonium sulphate as nitrogen source, sucrose as carbon source, presence of zinc sulphate in the medium and cultivation temperature of 25?C. The studied factors affected the dry biomass as well as the proportion of carotenoids and consequently the colour of pellets of the yeast. The yeast strain was grown under the optimal conditions to study the changes occurring in the medium and the pellets during carotenoids production for 6 days. Carotenoids production started after the first day of incubation and most of the carotenoids content in the yeast cells was produced during stationary phase. The highest cellular (861 μg?g–1) and volumetric (1.9 mg?L–1) carotenoids content were ob- tained after 5 days of growth.
Toluidine Blue O-Gelatin Gel Dosimeter for Radiation Processing  [PDF]
S. M. Gafar, M. A. El-Kelany, M. A. El-Ahdal, S. R. El-Shawadfy
Open Journal of Polymer Chemistry (OJPChem) , 2014, DOI: 10.4236/ojpchem.2014.43007
Abstract:

In this study the spectrophotometric response of the Toluidine Blue O (TBO)-gelatin gel dosimeter irradiated with gamma rays was characterized. Preparation of dyed-gelatin gel takes place in neutral medium; to give eventually gel dosimeter has a sharp absorbance peak at 635 nm that bleaches quantitatively upon irradiation and the colour change can be measured with UV-VIS spectrophotometer. The useful dose range was 1 - 150 Gy. The radiation chemical yield (G-value) of gel dosimeter was calculated and found to increase by increasing concentration of dye. Post-irradiation storage on the response of gel is discussed. The dose response function, radiation sensitivity, and dependences of the response on environmental factors were studied.

Use of the Newly Synthesized Aqueous Polyurethane Acrylate Binders for Printing Cotton and Polyester Fabrics  [PDF]
Mohamed M. El-Molla, Hanan S. El-Sayad, Madiha A. El-Kashouti, Rasha S. El-Khawaga
Advances in Chemical Engineering and Science (ACES) , 2012, DOI: 10.4236/aces.2012.22027
Abstract: The use of the four new synthesized polyurethane acrylate binders in the pigment print paste for screen printing cotton and polyester fabrics and pigment fixation through the polymerization process of the binder by using the thermofixation technique as well as the UV curing technique was studied. The effect of changing time and temperature of thermofixation, and the time of UV curing on the color strength, and prints fastness properties were also studied. The results showed that, the newly synthesized polyurethane acrylate binders could be successfully used for pigment fixation on cotton and polyester using the two fixation techniques and in general their prints possessed better color strength values as compared to those obtained upon using the selected commercial binders.
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