Aswan, Egypt

Time filter

Source Type

Shindy H.A.,Aswan University
Mini-Reviews in Organic Chemistry | Year: 2012

In this paper, the basic information, fundamental understanding, principles and/or knowledge of color, dyes and pigments chemistry via multi choice questions and their answers have been reviewed. More than two hundred multi choice questions and their answers have been represented in this paper review. The paper includes topics like, the relation between color and constitution and/or Witt's theory, fibers, nomenclature of dyes, definitions for dyes and pigments, types of dye binding to the fibers and other definitions and vital information in color, dyes and pigments chemistry. The paper also involves synthesis, properties, classifications and uses of many aromatic and/or heterocyclic dyes. Such dyes, like nitro dyes, nitroso dyes, azo dyes, diarylmethane dyes, triarylmethane dyes, anthraquinone dyes, cyanine dyes, azine dyes, phthaleine dyes, rehodamine dyes and indigoid dyes. Reviewing the basics, fundamental principles and/or the understanding of color, dyes and pigments chemistry via multi choice questions and their answers are considered a new and/or novel idea of reviewing which have not mentioned in the literature before. © 2012 Bentham Science Publishers.

Shindy H.A.,Aswan University
Mini-Reviews in Organic Chemistry | Year: 2012

Some essential basics, mechanisms and properties in the chemistry of cyanine dyes are reviewed, explained and/or illustrated in the paper. This involves and/or covers the generic structure of cyanine dyes, mesomeric structures of cyanine dyes, charge of the dye unit, quaternary salts used in the preparation of cyanine dyes, mechanism of styryl cyanine dyes, mechanism of aza-styryl cyanine dyes, mechanism of acyclic merocyanine dyes, mechanism of cyclic merocyanine dyes, mechanism of aromatic squarylium cyanine dyes, mechanism of heterocyclic squarylium cyanine dyes, acid-base properties of cyanine dyes, determination of the pKa values of cyanine dyes, solvatochromism, general and specific solvent effects, mixed solvent effects, advantages of cyanine dyes and disadvantages of cyanine dyes. In addition, in the introduction section of this review article some light is shed on the uses and applications of cyanine dyes. © 2012 Bentham Science Publishers.

Elsawy M.B.D.,Aswan University
Geosynthetics International | Year: 2013

Construction of embankments on soft natural soil may be a challenge, owing to its low shear strength and high compressibility. Stone columns, which depend on lateral support from the soft ground, have been utilised to accelerate foundation consolidation, and to increase foundation bearing capacity. To keep the drainage function, and to improve the stone columns as reinforcing elements, geosynthetics are used for column encasement. In this research, the behaviour of full-scale unreinforced and reinforced Bremerhaven clay with conventional and geogrid-encased stone columns under embankment loads is analysed numerically. The consolidation analysis is applied to investigate the long-term behaviour of the clay. The results show that the stone columns in the Bremerhaven clay increase the bearing capacity and accelerate the reduction of excess pore water pressure of the foundation. Once the stone columns are encased, more improvement occurs in their performance in soft soil. The analyses also indicate that stress concentration generation in the stone columns contributes significantly to the acceleration of soil consolidation. © 2013 Thomas Telford Ltd.

Darwish M.A.G.,Aswan University
International Journal of Sediment Research | Year: 2013

The goal of the present work is to perform a geochemical assessment of High Dam Lake bottom sediments for determining the fate, dispersion and levels of trace elements causing environmental pollution, and provided an access to their probable sources. The sediment samples were analyzed using ICP-MS for 20 elements; Ag, Ba, Cr, Cu, Ga, Hf, Mn, Pb, Rb, Sc, Se, Sn, Sr, Ta Th Ti, Tl, U, V and Zr, and their obtained data were treated using statistical, graphical and mapping techniques. The results showed the data set of all analyzed elements affected by outliers and extreme values that caused deviation away from normality. Kruskal-Wallis test revealed that median of some trace element levels in Lake sediments, was not significantly different and other elements rejected the Null hypothesis. Most analyzed elements had high values of median and mean in sediments of Lake Nubia rather than Lake Nasser and their normalization gave the same results of calculated environment factors. Subsequently, Lake Nubia sediments possessed high combined EF levels of Th, Sc, Sn, Ag, Zr, Hf, Ta, Sr, U, Ti, V, Cr, and Mn, causing significant contamination, which was great potentially related to industrial, agricultural, urbanization and mining activities. Whereas, combined EF of Se, Cu, Ga, Pb, Ba, Rb, and Tl, which are highly elevated in southern Lake Nasser sediments owing to their source are great possibly derived from Lake Nubia and geogenic activities. With decreasing distance towards the High Dam body, the contaminant elements were diminished due to reduction in the environmental factors and Sudanese pollution sources leading to the northern Lake Nasser considered to be less contaminated. Overall, the present study is an environmental alert for contaminated sediments that carried contaminants and considered the secondary source of pollution impact on ecosystem, and subsequently, their environmental risk on Human health. © 2013 International Research and Training Centre on Erosion and Sedimentation and the World Association for Sedimentation and Erosion Research.

Eid A.,Aswan University
International Journal of Electrical Power and Energy Systems | Year: 2014

This paper presents modeling, control and performance of a DC micro-grid connected to the utility under variable load demand and different environmental conditions. This micro-grid consists of 60 kW wind turbine (WT) energy conversion system, 40 kW photovoltaic (PV) panel and 40 kW fuel cell (FC) module, in addition to, DC and AC loads. The WT energy conversion system is controlled by the indirect field orientation control (FOC) method to extract maximum power from the wind. The PV module is controlled to generate the available maximum power using P&O MPPT control considering environmental conditions. The fuel cell, with a current controlled DC/DC boost converter, supplies power only when the load demand exceeds the total power of the WT and PV systems. A bidirectional 6-pulse PWM converter connects the micro-grid to utility using the natural frame control (NFC) technique. It controls the DC bus voltage, power and reactive power transfer to/from the utility according to the available power from the DG units and the total load demand. The various control algorithms are presented to harness the maximum power from the renewable energy sources at different operating modes. In addition, voltage stability and smooth power transfer between the micro-grid and utility are maintained. © 2014 Elsevier Ltd. All rights reserved.

Aim: To study the prevalence of pathogenic coagulase positive, methicillin-resistant Staphylococcus aureus (MRSA) in poultry meat and its products. Materials and Methods: A total of 125 poultry samples were collected during 2012 in Qena governorate for presence of pathogenic coagulase positive, methicillin-resistant staphylococcus aureus (MRSA). Samples were taken from freshly slaughtered whole chicken carcasses (25/125), chicken portions (25/125), chicken luncheon (25/125), chicken sausages (25/125) and chicken burgers (25/125). Results: It was observed that 44% (11/25), 52% (13/25), 40% (10/25), 24% (6/25) and 44% (11/25) of bacterial isolates were positive for methicillin-resistance tests for freshly slaughtered whole chicken carcasses, chicken portions, chicken luncheon, chicken sausages and chicken burgers respectively. Higher contamination rate of MRSAwas found in raw poultry meat and the lower rate in poultry meat products subjected to heat treatment and preservatives. Conclusion: Poultry meat and its products were considered as an important source of spreading of MRSAin humans. Hence, strict hygienic measures should be taken in poultry slaughter houses and in food preparing establishments.

Shabib G.,Aswan University
International Journal of Electrical Power and Energy Systems | Year: 2013

This paper is concerned with the plant modeling for the digital redesign of a continuous-time power system stabilizer PSS for a single machine power system using Plant-Input-Mapping PIM method. The traditional approach has been to use the bilinear transform (Tustin's method), but this needs small sampling intervals which gives some difficulties with modern control. The presented technique guarantees the stability for any sampling rate as well as it takes closed-loop characteristics into consideration. The proposed technique is successfully applied to the discretization of the conventional continuous time PSS for single-machine power system. For comparison studies the proposed technique is compared with conventional continuous-time PSS and Tustin's PSS. The simulation results show that the states of the proposed digital redesign technique closely match those of the conventional continuous-time PSS. The proposed digital redesign technique guarantees stability even with relatively slow sampling rates while Tustin's method falls when sampling interval becomes larger. © 2013 Elsevier Ltd. All rights reserved.

This paper presents a new methodology to calculate the ground surface electric field, produced by overhead transmission lines (OHTLs), taking into account the effect of the variation of the charge distributions along the conductors of multi-overhead transmission lines. In this paper, the effects of the conductors sag, the presence of the tower, replacing the sub-conductors of each phase with an equivalent conductor, the presence of the ground wires, and the presence of another overhead transmission line (OHTL) circuit on the electric charge distribution along the OHTL conductors and hence on the calculation of the ground surface electric fields are extensively studied. The suggested technique is verified by comparing its results with a measurement by the other. The suggested technique is based on both the Charge Simulation Method (CSM) and the Image Method (IM). © 2013 Elsevier Ltd. All rights reserved.

Abdel-Akher M.,Aswan University
IET Generation, Transmission and Distribution | Year: 2013

This study presents a new method for tracing voltage power curves in unbalanced radial distribution power systems. The proposed method starts with the base case loading conditions and leading to the maximum loading point (MLP) whereas no ill-conditioning problems were detected. The calculation is performed by first-order polynomial secant predictor and the solution is corrected using the backward/forward radial power-flow method. Adaptive stepwise control is implemented to improve the overall solution process and reduce the number of the calculated points along the traced curve. The results calculated using the developed method are for both a 33-bus radial feeder and the unbalanced IEEE 13-node and IEEE123-node feeders. The results show that the developed method accurately traces the voltage power curves up to MLP. Comprehensive analysis on unbalanced scenarios shows that load unbalance greatly affects the stability limit of the study system. ©The Institution of Engineering and Technology 2013.

Mohamed A.T.,Aswan University
International Journal of Electrical Power and Energy Systems | Year: 2015

The use of nanocomposite polymers as electrical insulating materials has been growing rapidly in recent decades. The base polyethylene properties have been developed by adding small amounts of different fillers to the polyethylene material. It is economically to get polymer development by using cost-fewer nanoparticles; therefore, polyethylene dielectric properties are trapped by presence cost-fewer nanofillers like clay and fumed silica which are importance in development manufacture of power cables products. Dielectric strength is a vital pointer for quality of insulation materials of electrical power applications; hence, experimental measurements have been investigated on ac high voltage breakdown of new cost-fewer polyethylene nanocomposites materials. All experimental results of the new polyethylene nanocomposites have been compared with conventional polyethylene insulation materials; therefore, it has been specified the influence types and their concentrations of cost-fewer nanofillers on dielectric strength of polyethylene nanocomposite insulation materials. © 2014 Elsevier Ltd. All rights reserved.

Loading Aswan University collaborators
Loading Aswan University collaborators