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2015
Salah, A., A. Mansour, M. B. Mohamed, I. M. Azzouz, S. Elnaby, and Y. Badr, "Effects of nanoparticles size and concentration and laser power on nonlinear optical properties of Au and Au-CdSe nanocrystals", Applied Surface Science, vol. 353, pp. 112-117, 2015. AbstractWebsite
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Umavathi, J. C., "Free convective flow in a vertical rectangular duct filled with porous matrix for viscosity and conductivity variable properties", International Journal of Heat and Mass Transfer, vol. 81, pp. 383 - 403, 2015. AbstractWebsite

Abstract Free convection over a vertical rectangular duct filled with porous matrix with variable viscosity and variable thermal conductivity is studied in this paper. We consider the two-dimensional steady laminar flow and Brinkman–Forchheimer extended Darcy model to define the porous medium. Using the appropriate variables the basic governing equations are transformed to non-dimensional governing equations. The fluid viscosity is assumed to vary exponentially with temperature whereas the thermal conductivity is assumed to vary linearly with temperature. One of the vertical walls of the duct is cooled with constant temperature while the other wall is heated to constant but different temperature. The governing coupled nonlinear momentum and energy equations are solved numerically using finite difference method. The effect of pertinent parameters such as variable viscosity, variable thermal conductivity, Darcy number, inertial parameter, Grashof number, Brinkman number and aspect ratio on the velocity, temperature, volumetric flow rate, shear stress and heat transfer are discussed.

Sagdinc, S. G., D. Erdas, I. Gunduz, and A. E. Sahinturk, "FT-IR and FT-Raman spectra, molecular structure and first-order molecular hyperpolarizabilities of a potential antihistaminic drug, cyproheptadine \{HCl\}", Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol. 134, pp. 350 - 360, 2015. AbstractWebsite

Abstract Cyproheptadine hydrochloride (CYP HCl) {4-(5H-dibenzo[a,d]-cyclohepten-5-ylidene)-1-methylpiperidine hydrochloride} is a first-generation antihistamine with additional anticholinergic, antiserotonergic, and local-anesthetic properties. The geometry optimization, Mulliken atomic charges and wavenumber and intensity of the vibrational bands of all of the possible modes of \{CYP\} \{HCl\} have been calculated using ab initio Hartree–Fock (HF) and density functional theory (DFT) employing the \{B3LYP\} functional with the 6-311G(d,p) basis set. We have compared the calculated İR\} and Raman wavenumbers with experimental data. Quantum-chemical calculations of the geometrical structure, energies, and molecular electrostatic potential and \{NBO\} analysis of \{CYP\} \{HCl\} have been performed using the B3LYP/6-311G(d,p) method. The electric dipole moment (μ), static polarizability (α) and the first hyperpolarizability (β) values of the title compound have been computed using \{HF\} and \{DFT\} methods. The study reveals that the antihistaminic pharmacological property of \{CYP\} \{HCl\} has a large β value and, hence, may in general have potential applications in the development of non-linear optical materials. The experimental and calculated results for \{CYP\} \{HCl\} have also been compared with those for mianserin HCl.

Meng, Q., A. Ren, L. Zhang, J. Liu, Z. Li, Y. Yang, R. Li, and L. Ma, "Incidence of infertility and risk factors of impaired fecundity among newly married couples in a Chinese population", Reproductive BioMedicine Online, vol. 30, no. 1, pp. 92 - 100, 2015. AbstractWebsite

Abstract The aims of this study were to obtain the incidence of infertility, to examine the causes of infertility and to explore risk factors for impaired fecundity in a rural region of northern China using a prospective follow-up design. A total of 2151 newly married couples planning to become pregnant within the next 12 months were enrolled between 2009 and 2012 from two counties of Shanxi Province in northern China. Couples were followed up for at least 1 year or until a clinical pregnancy occurred. Information about clinical pregnancy was obtained. The 12-month and 24-month infertility rates were 13.6% (95% \{CI\} 11.9 to 15.3) and 8.5% (95% \{CI\} 6.7 to 10.3), respectively. About 63% of women became pregnant within 6 months of follow up, and 86% did so within 12 months of follow up. The main causes of female infertility were ovulation disorders, fallopian tube problems and polycystic ovary syndrome. The primary cause of male infertility was sperm quality problems. Couples who used coal as cooking fuel, women with a higher body mass index, women with long-term health problems, and men who had married at later ages were more likely to have delayed pregnancies.

Ahmed, S. M., P. Szymanski, M. A. El-Sayed, Y. Badr, and L. M. El-Nadi, "The photoluminescence properties of undoped & Eu-doped ZnO thin films grown by RF sputtering on sapphire and silicon substrates", Applied Surface Science, vol. 359, pp. 356-363, 2015. AbstractWebsite
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Chehouri, A., R. Younes, A. Ilinca, and J. Perron, "Review of performance optimization techniques applied to wind turbines", Applied Energy, vol. 142, pp. 361 - 388, 2015. AbstractWebsite

Abstract This paper presents a review of the optimization techniques and strategies applied to wind turbine performance optimization. The topic is addressed by identifying the most significant objectives, targets and issues, as well as the optimization formulations, schemes and models available in the published literature. The current energy demand combined with depletion of fossil-fuel reserves and stricter environmental regulations have led to the development of alternative renewable energy solutions like wind energy. The current 2030 United States target is to have at least 20% of the \{US\} energy supply by onshore and offshore wind farms. To meet these demands, wind energy costs have to be able to compete with traditional fossil fuel sources. Hence, it is essential and vital that wind turbine designers and manufactures search the optimal solution that fits the objectives under a set of design constraints. Throughout the last 30 years, the objective function has evolved from the earlier maximized metric of the power coefficient to the maximization of the annual energy production. Common alternatives such as blade mass minimization and maximization of the rotor thrust and torque have been examined. However, the main objective has been focused on the minimization of the cost of energy in order for wind energy to become more competitive and economically attractive. The purpose of this paper is to review previous work that undertakes the performance optimization of horizontal wind turbines by highlighting the main aspects when tackling the wind turbine optimization problem such as: objective functions, design constraints, tools and models and optimization algorithms. In addition, in a conclusion of the review, a discussion and argument about the challenges, issues and future developments are identified.

Selvaggi, R., L. Tarpani, A. Santuari, S. Giovagnoli, and L. Latterini, "Silica nanoparticles assisted photodegradation of acridine orange in aqueous suspensions", Applied Catalysis B: Environmental, vol. 168–169, pp. 363 - 369, 2015. AbstractWebsite

Abstract Silica nanostructured materials are often used as catalyst support but their catalytic role has not been deeply investigated yet. In the present study, the photocatalytic degradation of acridine orange zinc chloride double salt (AO) has been studied using silica nanoparticles (NPs) as catalysts. \{NPs\} of different size (55 and 146 nm) were prepared by a sol–gel procedure and their surface was modified with amino groups to investigate the role of the chemical groups linked to the silica surface on the dye degradation. The silica nanomaterials were fully characterized by use of transmission electron microscopy (TEM), zeta potential measurements and UV–vis spectrophotometric methods. The photodegradation experiments were carried out irradiating at 313 or 490 nm for 50 min the aqueous samples containing the dye and the silica \{NPs\} of 55 or 146 nm in diameter. The photocatalytic degradation of the dye was determined from the decrease of its fluorescence intensity. \{AO\} fluorescence intensity did not change when bare SiO2 beads were used as catalysts, whereas an efficient decoloration (up to 58%) was achieved with amino functionalized NPs, with a photodegradation rate constant value of 0.136 m−1. The data collected from the degradation experiments demonstrated that the functional groups on the silica surface have a fundamental role in the efficiency of the degradation processes.

Cerón, E. M., R. C. Mateos, and F. García-Río, "Síndrome de apneas-hipopneas del sueño y diabetes tipo 2. ¿Una relación de ida y vuelta?", Archivos de Bronconeumología, vol. 51, no. 3, pp. 128 - 139, 2015. AbstractWebsite

Resumen Diversos datos epidemiológicos muestran que el síndrome de apneas-hipopneas del sueño (SAHS) se relaciona independientemente con el desarrollo de resistencia a la insulina e intolerancia a la glucosa. Además, y pese a la existencia de notables limitaciones metodológicas, algunos estudios refieren una elevada prevalencia de \{SAHS\} en pacientes con diabetes tipo 2 (DM2). Un reciente metaanálisis muestra que el \{SAHS\} moderado-grave se asocia a un mayor riesgo de \{DM2\} (riesgo relativo = 1,63 [1,09-2,45]), en relación con la ausencia de apneas-hipopneas. La existencia de alteraciones comunes de diversas vías patogénicas le proporciona plausibilidad biológica a esta relación. La hipoxia intermitente y la fragmentación del sueño, originadas por la sucesión de episodios de apneas-hipopneas, inducen diversos trastornos intermedios, como la activación del sistema nervioso simpático, el estrés oxidativo, la inflamación sistémica, alteraciones en las hormonas reguladoras del apetito y activación del eje hipotálamo-hipófiso-suprarrenal, que favorecen el desarrollo de resistencia a la insulina, así como su progresión a intolerancia a la glucosa y, en última instancia, a DM2. La coexistencia del \{SAHS\} parece agravar la evolución de la DM2, al empeorar el control glucémico y potenciar el efecto de la aterosclerosis en el desarrollo de complicaciones macrovasculares. Además, el \{SAHS\} podría asociarse al desarrollo de complicaciones microvasculares, particularmente la retinopatía, nefropatía o neuropatía diabéticas. Aunque todavía escasos, algunos datos sugieren que la \{DM2\} también podría empeorar la evolución del SAHS, al favorecer la colapsabilidad de la vía aérea superior y potenciar la aparición de apneas-hipopneas centrales. Abstract Epidemiological data suggest that sleep apnea-hypopnea syndrome (SAHS) is independently associated with the development of insulin resistance and glucose intolerance. Moreover, despite significant methodological limitations, some studies report a high prevalence of \{SAHS\} in patients with type 2 diabetes mellitus (DM2). A recent meta-analysis shows that moderate-severe \{SAHS\} is associated with an increased risk of \{DM2\} (relative risk = 1.63 [1.09 to 2.45]), compared to the absence of apneas and hypopneas. Common alterations in various pathogenic pathways add biological plausibility to this relationship. Intermittent hypoxia and sleep fragmentation, caused by successive apnea-hypopnea episodes, induce several intermediate disorders, such as activation of the sympathetic nervous system, oxidative stress, systemic inflammation, alterations in appetite-regulating hormones and activation of the hypothalamic-pituitary-adrenal axis which, in turn, favor the development of insulin resistance, its progression to glucose intolerance and, ultimately, to DM2. Concomitant \{SAHS\} seems to increase \{DM2\} severity, since it worsens glycemic control and enhances the effects of atherosclerosis on the development of macrovascular complications. Furthermore, \{SAHS\} may be associated with the development of microvascular complications: retinopathy, nephropathy or diabetic neuropathy in particular. Data are still scant, but it seems that \{DM2\} may also worsen \{SAHS\} progression, by increasing the collapsibility of the upper airway and the development of central apneas and hypopneas.

Aly, H. M., M. E. Moustafa, M. Y. Nassar, and E. A. Abdelrahman, "Synthesis and characterization of novel Cu (II) complexes with 3-substituted-4-amino-5-mercapto-1,2,4-triazole Schiff bases: A new route to CuO nanoparticles", Journal of Molecular Structure, vol. 1086, pp. 223 - 231, 2015. AbstractWebsite

Abstract Cu (II) complexes, were synthesized with newly derived biologically active 1,2,4-triazole Schiff bases. The Schiff bases were synthesized by condensation of 3-substituted-4-amino-5-mercapto-1,2,4-triazole with dibenzoylmethane. The synthesized compounds were characterized using elemental analysis, magnetic moment, thermal analysis and spectral tools (FT-IR, 1HNMR, ESR, and UV–Vis spectroscopy). All the synthesized complexes are nonelectrolytes in N,N-dimethylformamide. The synthesized Schiff bases and their Cu (II) complexes have been screened for antibacterial (Escherichia coli & Staphylococcus aureus) and antifungal (Aspergillus flavus & Candida albicans) activity using a modified Bauer-Kirby method. Interestingly, the synthesized Cu (II) complexes were used as precursors for CuO nanoparticles which were characterized using XRD, HR-TEM, FT-IR and UV–Vis spectroscopy. The photocatalytic activity of the prepared CuO nanoparticles was studied by performing the degradation of methylene blue dye under \{UV\} illumination in the presence of \{H2O2\} and the results showed that the maximum percent of the degradation of methylene blue dye (MB) was found 96.18% after 360 min.

Aly, H. M., M. E. Moustafa, M. Y. Nassar, and E. A. Abdelrahman, "Synthesis and characterization of novel Cu (II) complexes with 3-substituted-4-amino-5-mercapto-1,2,4-triazole Schiff bases: A new route to CuO nanoparticles", Journal of Molecular Structure, vol. 1086, pp. 223 - 231, 2015. AbstractWebsite

Abstract Cu (II) complexes, were synthesized with newly derived biologically active 1,2,4-triazole Schiff bases. The Schiff bases were synthesized by condensation of 3-substituted-4-amino-5-mercapto-1,2,4-triazole with dibenzoylmethane. The synthesized compounds were characterized using elemental analysis, magnetic moment, thermal analysis and spectral tools (FT-IR, 1HNMR, ESR, and UV–Vis spectroscopy). All the synthesized complexes are nonelectrolytes in N,N-dimethylformamide. The synthesized Schiff bases and their Cu (II) complexes have been screened for antibacterial (Escherichia coli & Staphylococcus aureus) and antifungal (Aspergillus flavus & Candida albicans) activity using a modified Bauer-Kirby method. Interestingly, the synthesized Cu (II) complexes were used as precursors for CuO nanoparticles which were characterized using XRD, HR-TEM, FT-IR and UV–Vis spectroscopy. The photocatalytic activity of the prepared CuO nanoparticles was studied by performing the degradation of methylene blue dye under \{UV\} illumination in the presence of \{H2O2\} and the results showed that the maximum percent of the degradation of methylene blue dye (MB) was found 96.18% after 360 min.

Babjaková, E., L. Dastychová, B. Hanulíková, I. Kuřitka, M. Nečas, H. Vašková, and R. Vícha, "Synthesis, molecular structure and vibrational spectra of 1,3-bis(1-adamantyl)-2-phenylpropan-1,3-diones", Journal of Molecular Structure, vol. 1085, pp. 207 - 214, 2015. AbstractWebsite

Abstract The interest in the oxo-enol tautomerism of 1,3-dioxo compounds is justified by their usefulness in many synthetic fields. A series of new 1,3-bis(1-adamantyl)propan-1,3-diones with a variably substituted phenyl ring at the \{C2\} position was prepared either by the reaction of an appropriate Grignard reagent with adamatane-1-carbonyl chloride or by \{SEAr\} on the unsubstituted 1,3-bis(1-adamantyl)-2-phenylpropan-1,3-dione. In addition to the single crystal X-ray diffraction analysis of three of the prepared compounds, the experimental 1H and 13C NMR, İR\} and Raman spectroscopic data were assigned and compared to those obtained by \{DFT\} computations. In the solid state, the syn-dioxo forms were exclusively observed, which are shown to also predominate in \{CHCl3\} solutions. The analysis of the Hirshfeld surface revealed that H⋯H and O⋯H contacts dominate the intermolecular interactions in the solid state, whereas π⋯π stacking plays a marginal role.

El-Bendary, N., Esraa Elhariri, A. E. Hassanien, and A. Badr, "Using machine learning techniques for evaluating tomato ripeness", Expert Systems with Applications, vol. 42, no. 4, pp. 1892 - 1905, 2015. AbstractWebsite

Abstract Tomato quality is one of the most important factors that helps ensuring a consistent marketing of tomato fruit. As ripeness is the main indicator for tomato quality from customers perspective, the determination of tomato ripeness stages is a basic industrial concern regarding tomato production in order to get high quality product. Automatic ripeness evaluation of tomato is an essential research topic as it may prove benefits in ensuring optimum yield of high quality product, this will increase the income because tomato is one of the most important crops in the world. This article presents an automated multi-class classification approach for tomato ripeness measurement and evaluation via investigating and classifying the different maturity/ripeness stages. The proposed approach uses color features for classifying tomato ripeness stages. The approach proposed in this article uses Principal Components Analysis (PCA) in addition to Support Vector Machines (SVMs) and Linear Discriminant Analysis (LDA) algorithms for feature extraction and classification, respectively. Experiments have been conducted on a dataset of total 250 images that has been used for both training and testing datasets with 10-fold cross validation. Experimental results showed that the proposed classification approach has obtained ripeness classification accuracy of 90.80%, using one-against-one (OAO) multi-class \{SVMs\} algorithm with linear kernel function, ripeness classification accuracy of 84.80% using one-against-all (OAA) multi-class \{SVMs\} algorithm with linear kernel function, and ripeness classification accuracy of 84% using \{LDA\} algorithm.

2014
Manikyamba, C., S. Ganguly, A. Saha, M. Santosh, R. M. Singh, and S. D. V. Rao, "Continental lithospheric evolution: Constraints from the geochemistry of felsic volcanic rocks in the Dharwar Craton, India", Journal of Asian Earth Sciences, vol. 95, pp. 65 - 80, 2014. AbstractWebsite

Abstract Felsic magmatism associated with ocean–ocean and ocean–continent subduction processes provide important evidence for distinct episodes of crust-generation and continental lithospheric evolution. Rhyolites constitute an integral component of the tholeiitic to calc-alkaline basalt–andesite–dacite–rhyolite (BADR) association and contribute to crustal growth processes at convergent plate margins. The evolution of the Dharwar Craton of southern peninsular India during Meso- to Neoarchean times was marked by extensive development of greenstone belts. These granite-greenstone terranes have distinct volcano-sedimentary associations consistent with their geodynamic setting. The present study deals with geochemistry of rhyolites from the Chitradurga-Shimoga greenstone belts of western (WDC) and the Gadwal-Kadiri greenstone belts of eastern (EDC) sectors of Dharwar Craton to compare and evaluate their petrogenesis and geodynamic setting and their control on the continental lithospheric evolution of the Dharwar Craton. At a similar range of SiO2, Al2O3, Fe2O3, the rhyolites of \{WDC\} are more potassic, whereas the \{EDC\} rhyolites are more sodic and less magnesian with slight increase in TiO2. Minor increase in MgO content of \{WDC\} rhyolites reflects their ferromagnesian trace elements which are comparatively lower in the rhyolites of EDC. The relative enrichment in \{LILE\} (K, Rb) and depletion in \{HFSE\} (Nb, Ta, Zr, Hf) marked by negative Nb–Ta, Zr–Hf and Ti anomalies endorse the convergent margin processes for the generation of rhyolites of both the sectors of Dharwar Craton. The high silica potassic rhyolites of Shimoga and Chitradurga greenstone belts of \{WDC\} showing prominent negative Eu and Ti anomalies, flat \{HREE\} patterns correspond to Type 3 rhyolites and clearly point towards their generation and emplacement in an active continental margin environment. The geochemical characteristics of Gadwal and Kadiri rhyolites from eastern Dharwar Craton marked by aluminous compositions with low and fractionated \{HREE\} patterns and minor negative Eu anomalies are in conformity with Type 1 rhyolites and suggest that they were erupted in an intraoceanic island arc system. The overall geochemical systematics of the rhyolites from both the sectors of Dharwar Craton suggest a change in the geodynamic conditions from intraoceanic island arc of eastern Dharwar Craton and an active continental margin of western Dharwar marked by ocean–ocean subduction and migration of oceanic arc towards a continent followed by arc-continent collision that contributed for the evolution of continental lithosphere in the Dharwar Craton.

Badr, I. H. A., M. Gouda, R. Abdel-Sattar, and H. E. M. Sayour, "Reduction of thrombogenicity of PVC-based sodium selective membrane electrodes using heparin-modified chitosan", Carbohydrate Polymers, vol. 99, pp. 783 - 790, 2014. AbstractWebsite

Abstract Heparin-modified chitosan (H-chitosan) membrane was utilized to enhance biocompatibility of sodium selective membrane electrode based on the highly thrombogenic polyvinyl chloride (PVC). Sodium ion sensing film was prepared using PVC, sodium ionophore-X, potassium tetrakis(chlorophenyl)-borate, and o-nitrophenyloctylether. The PVC-based sensing film was sandwiched to chitosan or H-chitosan to prevent platelet adhesion on the surface of PVC. Potentiometric response characteristics of PVC-chitosan and PVC-H-chitosan membrane electrodes were found to be comparable to that of a control \{PVC\} based sodium-selective electrode. This indicates that chitosan and H-chitosan layers do not alter the response behaviour of the PVC-based sensing film. Biocompatibility of H-chitosan was confirmed by in vitro platelet adhesion study. The platelet adhesion investigations indicated that H-chitosan film is less thrombogenic compared to PVC, which could result in enhancement of biocompatibility of sodium selective membrane electrodes based on PVC, while maintaining the overall electrochemical performance of the PVC-based sensing film.

Badr, I. H. A., M. Gouda, R. Abdel-Sattar, and H. E. M. Sayour, "Reduction of thrombogenicity of PVC-based sodium selective membrane electrodes using heparin-modified chitosan", Carbohydrate Polymers, vol. 99, pp. 783 - 790, 2014. AbstractWebsite

Abstract Heparin-modified chitosan (H-chitosan) membrane was utilized to enhance biocompatibility of sodium selective membrane electrode based on the highly thrombogenic polyvinyl chloride (PVC). Sodium ion sensing film was prepared using PVC, sodium ionophore-X, potassium tetrakis(chlorophenyl)-borate, and o-nitrophenyloctylether. The PVC-based sensing film was sandwiched to chitosan or H-chitosan to prevent platelet adhesion on the surface of PVC. Potentiometric response characteristics of PVC-chitosan and PVC-H-chitosan membrane electrodes were found to be comparable to that of a control \{PVC\} based sodium-selective electrode. This indicates that chitosan and H-chitosan layers do not alter the response behaviour of the PVC-based sensing film. Biocompatibility of H-chitosan was confirmed by in vitro platelet adhesion study. The platelet adhesion investigations indicated that H-chitosan film is less thrombogenic compared to PVC, which could result in enhancement of biocompatibility of sodium selective membrane electrodes based on PVC, while maintaining the overall electrochemical performance of the PVC-based sensing film.

Kassem, M. A., and R. M. Khafagy, "Thermal stability, crystallization kinetics and mechanical properties of Al81.8Ni9.2Co4.8Y3.1Zr1.1 amorphous alloy consolidated to a fully dense nanocrystalline matrix with some remaining amorphous phase", Journal of Alloys and Compounds, vol. 607, pp. 291 - 299, 2014. AbstractWebsite

Abstract High-strength nanocrystalline-embedded-alloy was successfully fabricated by the consolidation of melt-spun amorphous ribbons of Al81.8Ni9.2Co4.8Y3.1Zr1.1. The as-melt amorphous spun, the annealed and the fully dense nanocrystalline extruded specimens were investigated using XRD, HRTEM, SAED, \{EDX\} line mapping, microhardness, compression tests, \{SEM\} at fractured surfaces and the crystallization’s kinetics were determined from DSC. XRD, in good accordance with HRTEM, \{SAED\} and the associated \{EDX\} line mapping analysis, revealed the merely amorphous nature of the as-melt spun ribbons and confirmed bearing of nanocrystalline-embedded phases in the annealed and extruded specimens with the remaining of some amorphous phase. \{HRTEM\} and \{SAED\} revealed that annealing at 275 °C resulted in the formation of short-range ordered regions of fcc α-Al nanoparticles and intermetallic nanocrystalline-embedded grains of 5–10 nm that grown to 20–50 nm after extrusion. \{DSC\} showed that the as-melt spun ribbons crystallize at three stages in contrast to one late stage shown by the extruded sample. Crystallization kinetics of the as-spun ribbons yielded crystallization activation energy (Ec) of 143.4 and 36 kJ/mol for the first and second crystallization peaks respectively. The extruded specimen showed improved strength of 550 at a load of 50 g while the as-melt spun ribbons indicated lower hardness of 367 at a similar load. The ultimate compressive stress of the extruded specimen reached 800 MPa with 0.66% strain and Young’s modulus of 1.26 GPa. \{SEM\} micrographs of the fracture surface showed a transgranular failure with a dimpled surface reflecting the microplasticity of the final product. Improved mechanical properties and thermal stability of the nanocrystalline-embedded-specimen are due to the nanoparticle strengthening effect of the very hard and non-deformable nanosized α-aluminum and Al-based intermetallic nanograins that are densely formed during the annealing, extrusion and nano-indentation processes.

Kassem, M. A., and R. M. Khafagy, "Thermal stability, crystallization kinetics and mechanical properties of Al81.8Ni9.2Co4.8Y3.1Zr1.1 amorphous alloy consolidated to a fully dense nanocrystalline matrix with some remaining amorphous phase", Journal of Alloys and Compounds, vol. 607, pp. 291 - 299, 2014. AbstractWebsite

Abstract High-strength nanocrystalline-embedded-alloy was successfully fabricated by the consolidation of melt-spun amorphous ribbons of Al81.8Ni9.2Co4.8Y3.1Zr1.1. The as-melt amorphous spun, the annealed and the fully dense nanocrystalline extruded specimens were investigated using XRD, HRTEM, SAED, \{EDX\} line mapping, microhardness, compression tests, \{SEM\} at fractured surfaces and the crystallization’s kinetics were determined from DSC. XRD, in good accordance with HRTEM, \{SAED\} and the associated \{EDX\} line mapping analysis, revealed the merely amorphous nature of the as-melt spun ribbons and confirmed bearing of nanocrystalline-embedded phases in the annealed and extruded specimens with the remaining of some amorphous phase. \{HRTEM\} and \{SAED\} revealed that annealing at 275 °C resulted in the formation of short-range ordered regions of fcc α-Al nanoparticles and intermetallic nanocrystalline-embedded grains of 5–10 nm that grown to 20–50 nm after extrusion. \{DSC\} showed that the as-melt spun ribbons crystallize at three stages in contrast to one late stage shown by the extruded sample. Crystallization kinetics of the as-spun ribbons yielded crystallization activation energy (Ec) of 143.4 and 36 kJ/mol for the first and second crystallization peaks respectively. The extruded specimen showed improved strength of 550 at a load of 50 g while the as-melt spun ribbons indicated lower hardness of 367 at a similar load. The ultimate compressive stress of the extruded specimen reached 800 MPa with 0.66% strain and Young’s modulus of 1.26 GPa. \{SEM\} micrographs of the fracture surface showed a transgranular failure with a dimpled surface reflecting the microplasticity of the final product. Improved mechanical properties and thermal stability of the nanocrystalline-embedded-specimen are due to the nanoparticle strengthening effect of the very hard and non-deformable nanosized α-aluminum and Al-based intermetallic nanograins that are densely formed during the annealing, extrusion and nano-indentation processes.

2013
Ismail, T., J. M. El-Azab, and Y. A. Badr, "The impact of changing HNL-DSF parameters on wavelength exchanging", Proceedings of the 2013 2nd International Japan-Egypt Conference on Electronics, Communications and Computers, JEC-ECC 2013, pp. 143-147, 2013. Abstract
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Mabhaudhi, T., A. T. Modi, and Y. G. Beletse, "Response of taro (Colocasia esculenta L. Schott) landraces to varying water regimes under a rainshelter", Agricultural Water Management, vol. 121, pp. 102 - 112, 2013. AbstractWebsite

Taro [Colocasia esculenta (L.) Schott] is an underutilised crop in sub-Saharan Africa due to lack of agronomic research on it. There is no information describing water-use and drought tolerance of local taro landraces. Therefore, the objective of this study was to evaluate growth, yield and water-use of three South African landraces of taro under varying water regimes. Three taro landraces [Dumbe Lomfula (DL), KwaNgwanase (KW) and Umbumbulu (UM)] were planted in a rainshelter (14, October, 2010 and 8, September, 2011) at Roodeplaat, Pretoria, South Africa. Three levels of irrigation [30%, 60% and 100% crop water requirement (ETa)] were applied three times a week using drip irrigation. Emergence, plant height, leaf number, leaf area index (LAI) and stomatal conductance were measured in situ. Root length, fresh and dry mass were obtained by destructive sampling. Yield, yield components and water-use efficiency were determined at harvest. Taro landraces showed slow and uneven emergence. Stomatal conductance was respectively, 4% and 23% lower at 60% and 30% \{ETa\} relative to 100% ETa. Such a decline was clearer in the \{UM\} landrace, suggesting greater stomatal regulation in the \{UM\} landrace compared with \{KW\} and \{DL\} landraces. Plant growth parameters (plant height, leaf number and LAI) were shown to decrease by between 5% and 19% at 60% and 30% ETa, respectively, evapotranspiration relative to 100% ETa. The \{KW\} and \{DL\} landraces were shown to decrease the most while the \{UM\} landrace had moderate reductions in growth. Taro yield was 15% and 46% higher at optimum irrigation relative to 60% \{ETa\} and 30% ETa, respectively. Water-use efficiency was relatively unchanged (0.22–0.24 kg m−3) across varying water regimes. On average, the \{UM\} landrace had 113% higher \{WUE\} than the \{KW\} landrace. These findings can be used to differentiate the landraces on the basis of potential drought tolerance.

Atwa, D. M., N. Aboulfotoh, A. A. El-Magd, and Y. Badr, "Spectroscopic study of Pbs nano-structured layer prepared by Pld utilized as a Hall-effect magnetic sensor", AIP Conference Proceedings, vol. 1558, pp. 560-563, 2013. Abstract
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Shaaban, I. A., T. A. Mohamed, W. M. Zoghaib, L. D. Wilson, R. S. Farag, M. S. Afifi, and Y. A. Badr, "Tautomerism, Raman, infrared and ultraviolet-visible spectra, vibrational assignments, MP2 and B3LYP calculations of dienol 3,4-dihydroxypyridine, keto-enol 3-hydroxypyridin-4-one and keto-enol dimer", Journal of Molecular Structure, vol. 1043, pp. 52-67, 2013. AbstractWebsite
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2012
Ismail, T., J. M. El-Azab, and Y. A. Badr, "Wavelength exchanging technologies modeling, comparison, and validation", 2012 9th International Conference on High Capacity Optical Networks and Enabling Technologies, HONET 2012, pp. 97-101, 2012. Abstract
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2011
Graça, M. P. F., H. Fawzy, Y. Badr, M. M. Elokr, C. Nico, R. Soares, L. C. Costa, and M. A. Valente, "Electrical, dielectric and structural properties of borovanadate glass systems doped with samarium oxide", Physica Status Solidi (C) Current Topics in Solid State Physics, vol. 8, no. 11-12, pp. 3107-3110, 2011. AbstractWebsite
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Al-Shamiri, H. A. S., Y. A. Badr, and M. T. H. A. Kana, "Optical, photo-physical properties and photostability of laser dyes impregnated in sol-gel matrix", Saudi International Electronics, Communications and Photonics Conference 2011, SIECPC 2011, 2011. Abstract
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Tourism