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RISS 인기검색어
- 검색키워드
- 저자 : H. Y. Zahran (검색결과 4 건)
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A. F. Abd El‑Rehim,D. M. Habashy,H. Y. Zahran,H. N. Soliman 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10
An artificial neural network (ANN) model was used for the simulation and prediction of the mechanical properties ofSn-9Zn-Cu solder alloys. Sn-9Zn-Cu solder alloys containing different Cu contents (0, 1, 2, 3, 4 and 5 wt%) were successfullyprepared by permanent mold casting. The specimens were heated in a protective argon atmosphere at 433 K for 24 h,followed by water quenching at 298 K. Finally, the heat-treated samples were aged at 373 K for different time intervals (ta = 2,4, 8, 16 and 32 h), followed by water quenching at 298 K. The phases present in the current alloys were detected by X-raydiffraction analysis. For morphological characterization, a scanning electron microscope operated at 20 kV was tilized. Themechanical properties of the samples were studied using hardness measurements. The variations in the hardness data withincreasing aging time were determined based on the structural transformations that take place in the alloys. The ANN modelwas applied to the hardness measurements to simulate and predict the Vickers hardness of Sn-Zn-Cu alloys with mean squareerror values equal 9.55E-06 and 9.44E-06 for training and validation data respectively after 281 epochs. The simulated andpredicted results were consistent with the experimental results.
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Alshaikh, M.A.,Alsiadi, M.Y.,Zahran, S.M.,Mogawer, H.H.,Aalshowime, T.A. Asian Australasian Association of Animal Productio 2002 Animal Bioscience Vol.15 No.3
One hundred-fifty lactating, multiparous cow at post-peak of lactation were used to examine the effect of dietary yeast supplementation on milk production, milk composition and ruminal fermentation. The cows were randomly allocated to three groups of fifty cows each: a control group fed on a basal diet without yeast supplementation and two groups fed on basal diets supplemented with one of two commercial sources of yeast cultures, given at the rates of 15 g/head/d ($YC_1$) and 50 g/head/d ($YC_2$), respectively, as per manufacturers' recommendation. Daily milk production was recorded for all cows, while milk samples were taken randomly from ten cows per group for two consecutive days at two-week intervals for chemical analysis of the milk. Rumen fluids were also analyzed for ammonia nitrogen and volatile fatty acids. The results indicated that cows consuming diets supplemented with yeast culture tended to decrease their dry matter intake and to increase their milk yield. Cows fed $YC_2$ supplemented diet produced more milk and 4% fat corrected milk than those fed either $YC_1$-supplemented diet or the control. The highest milk fat percentage was obtained in cows fed $YC_2$ supplemented diet while the highest percentages of protein, lactose, total solids and solids not fat were recorded in cows fed $YC_1$. Rumen ammonia nitrogen concentration decreased significantly after yeast culture supplementation. Molar proportion of volatile fatty acids did not change significantly with yeast supplementation.
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Low Cost Alcoholic Breath Sensor Based on SnO2 Modified with CNTs and Graphene
M. Morsy,I. S. Yahia,H. Y. Zahran,M. Ibrahim 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.10
In this work, SnO2 modified with reduced graphene oxide (rGO) and carbon nanotubes (CNTs) separately and combined sensitized by using the co-precipitation method and their sensing behavior toward ethanol vapor at room temperature were investigated. An interdigitated electrode (IDE) gold substrate is very expensive compared to a uorine doped tin oxide (FTO) substrate; hence, we used the latter to reduce the fabrication cost. The structure and the morphology of the studied materials were characterized by using differential thermal analyses (DTA) and thermogravimetric analysis (TGA), transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller surface area and Barrett-Joyner- Halenda (BJH) pore size measurements. The studied composites were subjected to ethanol in its gas phase at concentrations from 10 to 200 ppm. The present composites showed high-performance sensitivity for many reasons: the incorporation of SnO2 and CNTs which prevents the agglomeration of rGO sheets, the formation of a 3D mesopourus structure and an increase in the surface area. The decoration with rGO and CNTs led to more active sites, such as vacancies, which increased the adsorption of ethanol gas. In addition, the mesopore structure and the nano size of the SnO2 particles allowed an ecient diffusion of gases to the active sites. Based on these results, the present composites should be considered as ecient and low-cost sensors for alcohol.
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Bimodal Approach for the Use of Co Doped Magnetite as MRI Contrast Agent and Potential Antitumor
Ahmed. A. G. El-Shahawy,Yasser GadelHak,H. Y. Zahran,I. S. Yahia,S. I. El-Dek 한국자기학회 2020 Journal of Magnetics Vol.25 No.4
Cobalt doped magnetite Co<SUP>2+</SUP> 0.1Fe<SUP>2+</SUP> 0.9Fe<SUP>3+</SUP> ₂O₄ nanocrystals were synthesized chemically using simple one step coprecipitation in the absence and presence of the magnetic field. The nanocrystals were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), magnetization studies by vibrational spectroscopy magnetometer (VSM). The signal intensity of the prepared nanoparticles was measured by magnetic resonance imaging (MRI). The cytotoxicity of the two samples versus W138 normal lung cells and AS49 lung cancer cells was investigated by MTT assay, in vitro. The TEM images showed non-spherical and aggregated nanoparticles, heterogeneously dispersed with 100 nm average size. The XRD and selected area electron diffraction of the two samples revealed good crystallinity for both samples. The room temperature magnetization curves demonstrate the general ferrimagnetic trend with a clear difference in the coercivity and the remanence keeping the saturation magnetization nearly stable. The measured MR signal intensity was well-matched with the result of the M-H loops where the sample prepared in the absence of the field was a promising T2 contrast agent. Both samples have low cytotoxicity compared to Doxorubicin.
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