Effect of Chromium Chloride on the Mechanical and Dielectric Properties of EPDM Rubber

M.A.Salem,M.A.Khaled,A.M.Hussein,E.Elway 한국고분자학회 2003 Macromolecular Research Vol.11 No.5

Measurements of Young’s modulus, dielectric loss and a.c. conductivity have been carried out on EPDM rubber samples loaded with different concentrations of CrCl3 (0,2,4 and 6 phr). The values of Young’s modulus was found to be linearly dependent on the CrCl3 content. Variation of the dielectric loss with temperature showed that CrCl3 may act as plasticizer. However, at higher frequencies the dielectric loss was found to be independent of frequency and the rubber samples may behave as non-polar dielectric. Investigations of the a.c conductivity suggested that the conduction in these rubber samples can be described by small polaron tunneling. In addition, conductivity was found to increase with CrCl3 content.

Effect of Chromium Chloride on the Mechanical and Dielectric Properties of EPDM Rubber

Salem, M.A.,Khaled, M.A.,Hussein, A.M.,Elway, E. The Polymer Society of Korea 2003 Macromolecular Research Vol.11 No.4

Measurements of Young's modulus, dielectric loss and a.c. conductivity have been carried out on EPDM rubber samples loaded with different concentrations of $CrCl_3$ (0,2,4 and 6 phr). The values of Young's modulus was found to be linearly dependent on the $CrCl_3$ content. Variation of the dielectric loss with temperature showed that $CrCl_3$ may act as plasticizer. However, at higher frequencies the dielectric loss was found to be independent of frequency and the rubber samples may behave as non-polar dielectric. Investigations of the a.c conductivity suggested that the conduction in these rubber samples can be described by small polaron tunneling. In addition, conductivity was found to increase with $CrCl_3$ content.

Distribution of Glutathione S-Transferase Omega Gene Polymorphism with Different Stages of HBV Infection Including Hepatocellular Carcinoma in the Egyptian Population

Shaban, Nadia Z,Salem, Halima H,Elsadany, Mohamed A,Ali, Bahy A,Hassona, Ehab M,Mogahed, Fayed AK Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.4

Background: Infection with hepatitis B virus (HBV) is a major global public health problem, with a wide spectrum of clinical manifestations. Human cytosolic glutathione-S-transferases (GSTs) include several classes such as alpha (A), mu (M), pi (P), sigma (S), zeta (Z), omega (O) and theta (T). The present study aimed to investigate the role of GST omega genes (GSTO1 and GSTO2) in different groups of patients infected with HBV. Materials and Methods: HBV groups were classified according to clinical history, serological tests and histological analysis into normal carriers (N), acute (A), chronic (CH), cirrhosis (CI) and hepatocellular carcinoma (HCC) cases. The study focused on determination of the genotypes of GST omega genes (GSTO1 and GSTO2) and GST activity and liver function tests. Results: The results showed that GSTO1 (A/A) was decreased in N, A, CH, CI and HCC groups compared to the C-group, while, GSTO1 (C/A) and GSTO1(C/C) genotypes were increased significantly in N, A, CH, CI and HCC groups. GSTO2 (A/A) was decreased in all studied groups as compared to the C-group but GSTO2(A/G) and GSTO2(G/G) genotypes were increased significantly. In addition, GST activities, albumin and TP levels were decreased in all studied groups compared to the C-group, while the activities of transaminases were increased to differing degrees. Conclusions: The results indicate that GSTO genetic polymorphisms may be considered as biomarkers for determining and predicting the progression of HBV infection.

Real-Time Implementation of On-Line Trained Neuro-Controller for a BLDC Motor

Salem, M.M.,Zahran, M.B.,Atia, Yousry,Zaki, A.M. The Korean Institute of Power Electronics 2003 JOURNAL OF POWER ELECTRONICS Vol.3 No.1

Implementation and experimental verification of a simple neuro-controller (SNC) as a speed controller for a brush less DC (BLDC) motor is presented. The SNC with one weight and a linear hard limit activation function is trained on-line using the back propagation algorithm. A modified error function is used to ensure good performance during the on-line training, which has been used without previous off-line training. The SNC has been implemented using a computer-interface card mounted on a PC. The driving system performance has been investigated by a number of experimental tests for a variety of input reference speed trajectories.

Real-Time Implementation of On-Line Trained Neuro-Controller For a BLDC Motor

M.M.Salem,M.B.Zahran,Yousry Atia,A.M.Zaki 전력전자학회 2003 JOURNAL OF POWER ELECTRONICS Vol.3 No.1

Implementation and experimental verification of a simple neuro-controller (SNC) as a speed controller for a brush less DC (BLDC) motor is presented The SNC with one weight and a linear hard limit activation function is trained on-line using the back propagation algorithm. A modified error function is used to ensure good performance during the on-line training, which has been used without previous off-line training. The SNC has been Implemented using a computer-interface card mounted on a PC The driving system performance has been investigated by a number of experimental tests for a variety of input reference speed trajectories.<br/>

Effect of Thermal Radiation on MHD Mixed Convective Heat Transfer Adjacent to a Vertical Continuously Stretching Sheet in the Presence of Variable Viscosity

A. M. Salem,Rania Fathy 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.6

An analysis is presented to study the combined free-forced convective laminar boundary layer flow adjacent to a vertical continuously stretching sheet in the presence of a magnetic field with variable viscosity and thermal radiation. The velocity and the temperature of the sheet were assumed to vary in a power law form, that is, uw= Bxm and Tw(x) − T∞ = Axn. The governing equations for the problem were changed to dimensionless ordinary differential equations by using a similarity transformation. The transformed governing equations in the present study were solved numerically by using the Runge-Kutta and Shooting method. A comparison between the analytical and the numerical solutions has been included. The effects of the variable viscosity parameter, the mixed convection parameter G*=Frx Re2x, the radiation parameter N and the magnetic field parameter M are discussed through graphs. Graphical results illustrating interesting features of the physics of the problem are presented and discussed.

Coupled Heat and Mass Transfer in Darcy-Forchheimer Mixed Convection from a Vertical Flat Plate Embedded in a Fluid-Saturated Porous Medium under the Effects of Radiation and Viscous Dissipation

A. M. Salem 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.3

This paper investigates the influence of viscous dissipation and radiation on the problem of Darcy-Frochheimer mixed convection from a vertical flat plate embedded in a fluid-saturated porous medium with thermal and mass diffusion. The fluid considered is a gray medium, and the Rosseland approximation is used to describe the radiative heat flux in the energy equation. A similarity solution for the transformed governing equations is obtained, and those equations are been solved by employing a numerical shooting technique with a fourth-order Runge-Kutta integration scheme. Numerical computations are carried out for the non-dimensional physical parameters. The results are analyzed for the effect of different physical parameters, such as radiation, natural and forced convection, the Ecret number, the buoyancy ratio, and the inertia parameter, on the flow, the heat, and the mass- transfer characteristics. "***

Eco-friendly Synthesis of New Polyfunctional Azo Dyes Using Shrimp Chitin as a Catalyst: Application on Polyester Fabrics and Their Biological Activities

Entesar A. Hassan,Hamada M. Mashaly,Zeinab M. Hashem,Salem E. Zayed,Ahmed M. Abo-Bakr 한국섬유공학회 2022 Fibers and polymers Vol.23 No.9

A series of varying and poly-functionalized heterocyclic compounds 3a-c, 4d-k, 6a,b, 8, 9, and 12 containing azofunction have been synthesized using 2-(1-(4-aminophenyl)ethylidene)malononitrile (1) and/or its diazonium salt as buildingblocks. In addition, new pyridazine derivatives 4a-c, 7a,b, and 13a-f were synthesized. Subsequent treating of the resultedazo dyes moieties with different reagents in conventional and green conditions using microwave irradiation and shrimp chitinas a green catalyst; homo- and hetero-molecules containing azo dyes were gathered. The obtained azo dyes were applied onfabrics at high temperatures and their properties such as washing fastness using standard soap (SDS) and rubbing fastness(wet and dry) under controlled conditions of pressure, speed, and moisture were studied. In addition, they were screened fortheir biological activities on two bacterial and two mycolic species. The synthesized products were characterized by theirelemental and spectral analyses such as IR, MS, 1H-NMR, and 13C-NMR spectra. The produced dyestuffs 3a-c, 4d, f, h, i, j,6a,b, 8, and 12 were dyed on polyester fabrics, and subsequently their dyeing properties and their light, washing, perspiration,rubbing, and sublimation fastness was determined and the dyed samples showed very good fastness levels to rubbing,washing, thermal fixation, good light, and possessed very good perspiration fastness.

Statistical analysis of compressive strength data of ceramic Raschig rings fabricated by an extrusion process using a Weibull distribution

M. Salehi,A. Salem 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.2

The influence of sintering conditions on the reliability of a special ceramic packing namely a Raschig ring, was investigated. The special kaolin used in the industrial ceramic Raschig rings manufacturing process was shaped by an extrusion method and sintered at 1200 and 1250oC using different soaking times, ranging from 30 to 180 minutes. The physico-chemical properties of specimens such as shrinkage, water absorption, bulk density, porosity, microstructure and mineralogical composition, were studied. According to the obtained results, the best sintering conditions were determined. The diametrical compressive strength of fired samples was measured on suitable specimens. The differences found in the strength data were evaluated using Weibull theory. The statistical results show that the maximum Weibull modulus is obtained when ceramic Raschig rings are fired at a lower sintering temperature and longer soaking time to reach the minimum total porosity. However, the soaking time needs to be optimized to realize the maximum strength and reliability during the fabricating process at a given temperature. The influence of sintering conditions on the reliability of a special ceramic packing namely a Raschig ring, was investigated. The special kaolin used in the industrial ceramic Raschig rings manufacturing process was shaped by an extrusion method and sintered at 1200 and 1250oC using different soaking times, ranging from 30 to 180 minutes. The physico-chemical properties of specimens such as shrinkage, water absorption, bulk density, porosity, microstructure and mineralogical composition, were studied. According to the obtained results, the best sintering conditions were determined. The diametrical compressive strength of fired samples was measured on suitable specimens. The differences found in the strength data were evaluated using Weibull theory. The statistical results show that the maximum Weibull modulus is obtained when ceramic Raschig rings are fired at a lower sintering temperature and longer soaking time to reach the minimum total porosity. However, the soaking time needs to be optimized to realize the maximum strength and reliability during the fabricating process at a given temperature.

Influence of palm oil fuel ash on behaviour of green high-performance fine-grained cement mortar

Sagr, Salem Giuma Ibrahim,Johari, M.A. Megat,Mijarsh, M.J.A. Techno-Press 2022 Advances in materials research Vol.11 No.2

In the recent years, the use of agricultural waste in green cement mortar and concrete production has attracted considerable attention because of potential saving in the large areas of landfills and potential enhancement on the performance of mortar. In this research, microparticles of palm oil fuel ash (POFA) obtained from a multistage thermal and mechanical treatment processes of raw POFA originating from palm oil mill was utilized as a pozzolanic material to produce high-performance cement mortar (HPCM). POFA was used as a partial replacement material to ordinary Portland cement (OPC) at replacement levels of 0, 5, 10, 15, 20, 25, 30, 35, 40% by volume. Sand with particle size smaller than 300 ㎛ was used to enhance the performance of the HPCM. The HPCM mixes were tested for workability, compressive strength, ultrasonic pulse velocity (UPV), porosity and absorption. The results portray that the incorporation of micro POFA in HPCMs led to a slight reduction in the compressive strength. At 40% replacement level, the compressive strength was 87.4 MPa at 28 days which is suitable for many high strength applications. Although adding POFA to the cement mixtures harmed the absorption and porosity, those properties were very low at 3.4% and 11.5% respectively at a 40% POFA replacement ratio and after 28 days of curing. The HPCM mixtures containing POFA exhibited greater increase in strength and UPV as well as greater reduction in absorption and porosity than the control OPC mortar from 7 to 28 days of curing age, as a result of the pozzolanic reaction of POFA. Micro POFA with finely graded sand resulted in a dense and high strength cement mortar due to the pozzolanic reaction and increased packing effect. Therefore, it is demonstrated that the POFA could be used with high replacement ratios as a pozzolanic material to produce HPCM.