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Search Results: 1 - 10 of 462198 matches for " Nawal A. A. Jalil "
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Effects of Structural Parameters on the Dynamics of a Beam Structure with a Beam-Type Vibration Absorber
Mothanna Y. Abd,Azma Putra,Nawal A. A. Jalil,Jamaludin Noorzaei
Advances in Acoustics and Vibration , 2012, DOI: 10.1155/2012/268964
Abstract: A beam-type absorber has been known as one of the dynamic vibration absorbers used to suppress excessive vibration of an engineering structure. This paper studies an absorbing beam which is attached through a visco-elastic layer on a primary beam structure. Solutions of the dynamic response are presented at the midspan of the primary and absorbing beams in simply supported edges subjected to a stationary harmonic load. The effect of structural parameters, namely, rigidity ratio, mass ratio, and damping of the layer and the structure as well as the layer stiffness on the response is investigated to reduce the vibration amplitude at the fundamental frequency of the original single primary beam. It is found that this can considerably reduce the amplitude at the corresponding troublesome frequency, but compromised situation should be noted by controlling the structural parameters. The model is also validated with measured data with reasonable agreement. 1. Introduction A beam-type absorber is one of the techniques to reduce undesirable vibration of many vibrating systems, such as a synchronous machine, mounting structure for a sensitive instrument, and other continuous structure in engineering. The absorber system usually consists of a beam attached to the host structure using an elastic element. The natural frequency of the absorber is then tuned to be the same as the troublesome operating frequency of the host structure to create counter force, which in return reduces the vibration of the structure. As beams are important structures in civil or mechanical engineering, several works have also been established to investigate the performance of the absorbing beam which is attached also to a beam structure. Among the earliest studies of the double-beam system is one proposed by Yamaguchi [1], which investigated the effectiveness of the dynamic vibration absorber consisting of double-cantilever visco-elastic beam connected by spring and viscous damper. The auxiliary beam is attached to the center of the main beam excited at its end by a sinusoidal force. It is found that the amplitude at resonances of the main beam is sensitive to the stiffness and mass of the absorbing beam. The damping ratio was formulated as a function of mass and layer stiffness of the absorber. Vu et al. [2] studied the distributed vibration absorber under stationary distributed force. A closed form was developed by utilizing change of variables and modal analysis to decouple and solve differential equations. Oniszczuk [3] studied the free vibrations of two identical parallel simply
Adsorptive Stripping Anodic Voltammetric Determination of Thioctic Acid in Bulk and Pharmaceutical Formulations
Nawal A. Alarfaj
International Journal of Biomedical Science , 2009,
Abstract: The electrochemical behavior of thioctic acid at the hanging mercury drop electrode was studied in different supporting electrolytes. In Britton - Robinson buffer pH 3.29, the square - wave adsorptive anodic stripping voltammogram of thioctic acid exhibited a single well - defined anodic peak at about -0.21 V . vs Ag/AgCl .The peak response was characterized with respect to pH, preconcentration time , accumulation potential, supporting electrolytes, frequency, scan increment and pulse amplitude. Under the optimized conditions, a fully validated, simple, high sensitive, precise and inexpensive square - wave adsorptive anodic stripping voltammetric procedure was described for determination of thioctic acid in bulk form and tablets. The obtained results were in good agreement with those obtained with the reference method. The calibration graph was linear over the range 5 × 10-8 - 9 × 10-7 M (r=0.9997) with accumulation for 60 s at -0.4 V vs Ag/AgCl and the detection limit was ca. 1.2 × 10-8 M.
Effects of Exposure to Electromagnetic Field on of Some Hematological Parameters in Mice  [PDF]
Mariam S. Alghamdi, Nawal A. El-Ghazaly
Open Journal of Medicinal Chemistry (OJMC) , 2012, DOI: 10.4236/ojmc.2012.22005
Abstract: Objective: To investigate the effects of electromagnetic fields on some hematological parameters of Male white mice. Methods: In this study two experiments were used as short-term and long-term experiments. Short-term experiments were carried out in 80 male white Balb/c mice exposed to two types of mobile phone for a period time up to 60 min a day for 2 weeks. Long-term experiments was carried out in 30 male white Balb/c mice exposed to two types of mobile phone for a period time up to 90 min a day for a day for a month, two months, three months. Result: The present result found that a decline in hemoglobin, hematocrit, red blood cells count, in addition to the platelets count after short and long exposure to both types of mobile phone (Alcatel, Nokia,). It was observed that the average number of white cells and lymphocytes increased significantly, indicating the increase to the body’s immune response to radiation. Also, when exposed to both devices (Alcatel, Nokia) for 15 minutes, the red blood cells began to take roles formation due to an increase in the viscosity of the blood and the ability of the cells adhesion. Increased duration of exposure to 30-minute to both devices revealed disparities in the sizes of red blood cells with the appearance of a large proportion of cells with pale colors due to lack of hemoglobin. In the group exposed for 45 minutes showed clearly the influence of mobile phones on examining blood smears which observed a proportion variation in the cell sizes with the emergence of forms of abnormal forms, including pellets cleft with many areas empty of red blood cells, With increasing in of exposure duration to 60 minutes, red blood cells appeared completely different from the natural form and took the forms resembling the eye and tear that appear in the case of anemia. After three months of exposure to both types of mobile phone showed pathological changes in red blood cells where gripped the outer membrane of the red corpuscle changes and become serrated. Conclusion: Exposure to electromagnetic fields is responsible for the variations of some hematological parameters in rats.
Potash Breakdown of Poly-Mineralized Niobium-Tantalum-Lanthanides Ore Material  [PDF]
Mona N. El Hazek, Nawal H. Mohamed, Azza A. Gabr
American Journal of Analytical Chemistry (AJAC) , 2019, DOI: 10.4236/ajac.2019.103009
Abstract: The potentiality of the alkali breakdown of the poly mineralized ore material south Gabal El-A’urf area, central Eastern Desert, Egypt is investigated. It includes the multiple oxide mineral tanteuxenite, monazite, bastnasite, anatase, as well as zircon. This ore material assaying lanthanides (RE2O3 1.9%), niobium (Nb2O5 1.25%) as well as titanium and zirconium (TiO2 and ZrO2 1.23% and 1.12%) respectively besides tantalum (Ta2O5 0.13%), were used for the present work. This sample has thus been subjected to two alkali breakdown techniques using potash; namely agitation leaching and fusion. The latter technique was found to be preferred as it gives higher leaching efficiency. The optimum leaching conditions are weight ratio of the ore/potassium hydroxide 1/2 at 400°C for 1 h. The realized leaching efficiencies attained 95.0% and 93.7% for Nb and Ta respectively as well as 96% for lanthanides and 75% for Ti while that for Zr did not exceed 10%.
El pensamiento antropocéntrico y la idea de la perfección en la naturaleza: selección natural o sobrenatural?
Ana María Jalil
Boletín Biológica , 2010,
Abstract:
Numerical Solutions of the Regularized Long-Wave (RLW) Equation Using New Modification of Laplace-Decomposition Method  [PDF]
Nawal A. Al-Zaid, Huda O. Bakodah, Fathiah A. Hendi
Advances in Pure Mathematics (APM) , 2013, DOI: 10.4236/apm.2013.31A022
Abstract:

In this paper the new modification of Laplace Adomian decomposition method (ADM) to obtain numerical solution of the regularized long-wave (RLW) equation is presented. The performance of the method is illustrated by solving two test examples of the problem. To see the accuracy of the method, L2 and L error norms are calculated.

Effect of Wild Marjoram (Origanum vulgare) Plant Extracts on Capacitation of Sheep Spermatozoa in Vitro  [PDF]
Ebtesam S. Alenezy, Ibrahim A. H. Barakat, Nawal M. Al Musayeib
Advances in Bioscience and Biotechnology (ABB) , 2019, DOI: 10.4236/abb.2019.104006
Abstract: The purpose of this study was to evaluate the effect of the addition of Origanum vulgare extract to in vitro capacitation sperm medium (IVCSM). This study investigated the antioxidant and antimicrobial effects of O. vulgare extracts at different concentrations (0.3, 0.6, 1.2 μg/ml and 25.0, 50.0, 100.0 μg/ml, respectively) in IVCSM. Significant enhancements in semen quality parameters such as total motility, live and live capacitated sperm were found when O. vulgare extract was added as an antioxidant source (1.2 μg/ml). The treatment of spermatozoa with O. vulgare extract at the highest concentration (100 μg/ml) for 2 hrs without antibiotics improved sperm characteristics. In conclusion, incubation of sperm with O. vulgare extract in capacitation medium had beneficial effects on the characteristics of ram sperm.
Enhancements in the Security Level for Wireless Sensor Network  [PDF]
Amr M. Kishk, Nagy W. Messiha, Nawal A. El-Fishawy, Abd-Elrahman A. Alkafs, Ahmed H. Madian
Journal of Information Security (JIS) , 2015, DOI: 10.4236/jis.2015.63022
Abstract: The trade off between the energy consumption and the quality of the received image should be considered as a main point in the techniques design in Wireless Sensor Network (WSN). This paper analyzes the performance of multiple image encryption algorithms with different approaches. And also, it introduces two proposed modulation techniques to enhance the performance of WSN. These two techniques merge both the image and the audio in one signal. The merging process enhances the energy consumption data rate. In addition, it removes the effectiveness of the jamming completely from both the reconstructed image and reconstructed audio signal at the receiver. So, the receiver will reconstruct the image without jamming effectiveness. The paper introduces a proposed audio encryption algorithm. The use of encryption algorithms for both image and audio signals with the merging process enhances the security level. Popular metrics are used to compare between these image encryption algorithms and also to show the benefits from these enhancements. The results show the preference of one of these image encryption algorithms to others. And also, the merging process enhances the bit rate to high level.
Sensitivity and Specificity of Various Serological Tests for Detection of Brucella spp. Infection in Male Goats and Sheep  [PDF]
Waffa A. Ahmed, Shaimaa A. Majeed, Ameer H. Abdul Ameer, Nawal D. Mahmmod, Nameer I. Saeed, Luma. Y. Hanaa
Advances in Microbiology (AiM) , 2016, DOI: 10.4236/aim.2016.62010
Abstract: Brucellosis is a zoonosis found throughout the world with major implications both in the field of public health and farming economy. It is most often caused by Brucella abortus and Brucella melitensis. This study aimed for evaluation of the sensitivity and specificity of immunochromatographic assay (ICA) and comparing the results with those obtained from Rose Bengal Plate Test (RBPT) and in direct Enzyme Linked Immunsorbent Assay (ELISA) for serodiagnosis of sheep and goat brucellosis. Out of 41 sera samples (21 ram and 20 male goats) which were examined, antibodies against Brucella were detected in ram 8 (38.09%), 6 (28.57%) and 16 (76.19%) in ram samples, whereas they were detected in 3 (15%), 1 (5%) and 12 (60%) serum sample of goats males by RBPT, (ICA) and iELISA respectively. The kappa value between iELISA and ICA was -0.08 and that between RBPT and ELISA was -0.01 in ram and the kappa value between iELISA and ICA was -0.06 and that between RBPT and ELISA was -0.14 in male goats. The sensitivity for RBPT and ICA were 37.5% and 25% while specificity was 60% and 60% in ram; whereas, in male goats, sensitivity for RBPT was 8.33% and ICA was 8.33% while specificity was 75% and 100% respectively. It can be concluded that the developed ICA is immunodiagnostic assay, and it is rapid, non-expensive, economical and suitable for large-scale screening in developing countries and rural areas.
Detection and Quantification of Anti-Inflammatory Cytokine in Sera and Urine of Sudanese Patients Infected with Schistosoma haematobium  [PDF]
A. Hammad, Manahil Nouri, Abdelbagi Alfadil, H. A. Musa, M. A. Osman, A. Bashir, Nawal Eltayeb Omer, Yasir Hassan, A. Alfarazdeg, A. Mustafa
Open Journal of Medical Microbiology (OJMM) , 2016, DOI: 10.4236/ojmm.2016.61006
Abstract: Cytokines have been in focus of scientific in for more than decade now. Analyzing their expression has enabled a better understanding of pathogenesis of various diseases. Moreover, they are now for beyond their stage when they were of interest for pathophysiological research. In the present study, we used an assay to anti-inflammatory cytokines. One hundred and thirty sera and urine from egg positive individuals and 42 samples of healthy individuals in Eldeum locality—an endemic area of S. haematobum and 28 healthy individuals from non-endemic area were tested. Concentration of IL5 and IL10 is reverse. IL5 is low in serum but high in urine before treatment and high in serum and low in urine after treatment. IL10 is high in serum, low in urine before treatment and low in serum, high in urine after treatment.
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