Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2019 ( 113 )

2018 ( 164 )

2017 ( 129 )

2016 ( 166 )

Custom range...

Search Results: 1 - 10 of 52555 matches for " Mothanna Y. Abd "
All listed articles are free for downloading (OA Articles)
Page 1 /52555
Display every page Item
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
Deep Venous Thrombosis: Commonly Affected Veins in the Lower Limbs  [PDF]
Sultan Abdulwadoud Alshoabi, Abdullatif Mothanna
Journal of Biosciences and Medicines (JBM) , 2019, DOI: 10.4236/jbm.2019.73002
Abstract: Aim and Objectives: This study aimed to record the commonly affected veins in the lower limbs, to compare the affected sides and gender and to correlate the Doppler findings and stages of deep venous thrombosis (DVT). Materials and Methods: A descriptive retrospective study of 46 already diagnosed cases of lower limb DVT. Results: Out of 46 cases of DVT, 71.74% were females. The majority of patients (93.47%) were affected in unilateral lower limb with significant predominance (65.22%) to affect the left lower limb (p < 0.001). The common femoral vein (CFV) was affected in 71.7% of cases. The superficial femoral vein (SFV) was affected in 71.7% of cases. The popliteal vein was affected in 67.4%. The deep femoral vein was affected only in 17.4%. Both CFV and SFV were affected together in 47.8% of cases. Both SFV and popliteal vein were affected together in 50% of cases. The majority of DVT cases (71.1%) were in the acute stage. This study revealed an essential relationship between the acute stage of DVT and distension of the affected veins (p < 0.001) (OR 20.667, 95% CI 3.826 - 111.633). It also detected a significant relationship between the acute stage and absence of venous blood flow (p < 0.001) (OR 90.667, 95% CI 8.303 - 990.114). Conclusion: Lower limb deep venous thrombosis affects left lower limb more than right and females more than males. Superficial femoral vein (SFV) and common femoral vein (CFV) are the most common affected veins. Lower limb DVT predominantly present in acute stage with venous distension and absent blood flow.
Enzymatic and histopathologic biomarkers as indicators of aquatic pollution in fishes  [PDF]
Alaa G. M. Osman, Abd-El –Baset M. Abd El Reheem, Khalid Y. AbuelFadl, Ali G. GadEl- Rab
Natural Science (NS) , 2010, DOI: 10.4236/ns.2010.211158
Abstract: In the present study we investigated the alteration in the activity of two metabolic enzymes [Glucose-6-Phosphate Dehydrogenase (G6PDH) and Lactate Dehydrogenase (LDH)] and the histological changes on liver and gills of the African catfish Clarias gariepinus collected from 6 sites along the river Nile, from its spring at Aswan to its estuary at Rosetta and Damietta branches. The results showed that the physical and chemical parameters of the water collected from Damietta and Rosetta branches were higher than those of the water collected from other sites. Remarkable alterations in the activity of the selected enzymes in the liver and muscles of the African catfish were detected. These alterations go in parallel with the elevation in the levels of chemical parameters detected in the water of Damietta and Rosetta branches as a result of pollution stress in these areas. The activity of G6PDH was significantly (p < 0.05) decreased from Aswan to Rosetta and Damietta recording the highest value at Rosetta followed by Damietta water. The activity of LDH showed a significant elevation (p < 0.05) in activity in the liver and muscles of fishes collected from Rosetta and Damietta branches comparing to other sites. These alterations in enzymatic activities were followed, in the present study, by the occurrence of histological lesions and clear damage in liver and gill tissues of the African catfish collected from the same sites. Thus we may conclude that, the altered activities of G6PDH and LDH could be useful biomarkers of water pollution. At the same time, histopathology provides a reliable, easily quantifiable index of low-level toxic stress to a broad range of environmental pollutants.
Efficient Multiobjective Genetic Algorithm for Solving Transportation, Assignment, and Transshipment Problems  [PDF]
Sayed A. Zaki, Abd Allah A. Mousa, Hamdy M. Geneedi, Adel Y. Elmekawy
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.31015
Abstract: This paper presents an efficient genetic algorithm for solving multiobjective transportation problem, assignment, and transshipment Problems. The proposed approach integrates the merits of both genetic algorithm (GA) and local search (LS) scheme. The algorithm maintains a finite-sized archive of non-dominated solutions which gets iteratively updated in the presence of new solutions based on clustering algorithm. The use clustering algorithm makes the algorithms practical by allowing a decision maker to control the resolution of the Pareto set approximation. To increase GAs’ problem solution power, local search technique is implemented as neighborhood search engine where it intends to explore the less-crowded area in the current archive to possibly obtain more nondominated solutions. The inclusion of local search and clustering algorithm speeds-up the search process and also helps in obtaining a fine-grained value for the objective functions. Finally, we report numerical results in order to establish the actual computational burden of the proposed algorithm and to assess its performances with respect to classical approaches for solving MOTP.
Evidence of Fungicides Degradation by Rhizobia  [PDF]
Hassan Moawad, Wafaa M. Abd El-Rahim, Haitham Shawky, Aziz M. Higazy, Zakaria Y. Daw
Agricultural Sciences (AS) , 2014, DOI: 10.4236/as.2014.57065

Fungicides which are not easily degradable have the greatest adverse effects on soil microbes. These pesticides negatively affect the growth and multiplication of fungi and bacteria and consequently cause the disturbance of the natural soil microbial balance. In this study two fungicide tolerant isolates of rhizobia; clover isolate (TA1) and peanut isolate (8) were assessed in their capacity to degrade Vitavax and Rizolex. The performance of these isolates in fungicides degradation was tested using the colorimetric assay for Rizolex and the HPLC analysis for Vitavax to detect the degradation products. Using HPLC analyses, the control sample showed specific peak indicating the Vitavax presence in the medium. The specific peak did not change in the control samples throughout the experiment.With the strainTA1 the specific peak of the Vitavax fungicides started to reduce as the incubation time goes on. The Vitavax fungicide did not degrade completely after 240 hours of incubation with rhizobial isolate. The Rizolex used in this study contained blend of Thiram (active ingredient of Rizolex) and Tolcofs methyl fungicides in 1:1 ratio. The biodegradation of Rizolex in the liquid media showed the formation of two new intermediates which were released into the medium indicating the degradation of the tested fungicide by peanut rhizobial isolate No. 8 in 48 hrs of incubation 45% of this compound was degraded. This work shows that the selection of fungicides tolerant rhizobial strains is important to protect the rhizobial inoculants from the toxic effect of the pesticides.

Trichomoniasis in Pregnant Sudanese Pregnant Women at Tertiary Obstetric Facility, Khartoum, Sudan  [PDF]
Hanan A. O. Abd Allha, A. Fazari, Khalid Y. M. Ahmed
Open Journal of Obstetrics and Gynecology (OJOG) , 2016, DOI: 10.4236/ojog.2016.69069
Abstract: Background: Trichomoniasis is a common Sexually Transmitted Disease (STD) and the most common curable one. Methodology: This was cross sectional, prospective, total coverage hospital based study. It aimed to determine the incidence, risk factors of the Trichomoniasis among the laboring Sudanese women at Omdurman New Hospital Khartoum-Sudan, from September 2012 to April 2013. Data were obtained, entered and analyzed using soft word package program for social science (SPSS) version 17. Results: The prevalence of Trichomoniasis is 6.8%. It was found that the awareness about the infection is very low only 35%. Diabetes and history of sexual transmitted infections are the risks seen among the study cases. Preterm labor was seen significantly. Conclusion: Syndromic management of all women with abnormal vaginal discharge is important since it causes reproductive morbidity.
Implementation of HACCP Plan for the Production of Egyptian Kishk (A Traditional Fermented Cereal-Milk Mixture)  [PDF]
Mohamed M. Abd El-Razik, Mohamed F. Y. Hassan, Mohamed G. E. Gadallah
Food and Nutrition Sciences (FNS) , 2016, DOI: 10.4236/fns.2016.713116
Abstract: The aim of this study is implementation of Hazard Analysis and Critical Control Points (HACCP) system during production of Egyptian Kishk on small scale production. Kishk is a traditional dry fermented product consisted from salted sour butter milk (Laban zeer) or yoghurt with cracked and bran free parboiled wheat grains (Burghol); the mixture of cereal and milk allows fermenting at ambient temperature for different periods, then the fermented mixture is formed in ball form and dried. Kishk is consumed in Egypt and in most Arab countries. Since Kishk is prepared by traditional and consumed widely, safety of this product is very important in terms of consumer health. Therefore, HACCP system as food safety tool was adopted during preparation of Kishk. Hazard analysis of raw materials and during different production steps was established. A simple HACCP plan was implemented; critical control points of production were determined; critical limits, corrective actions and monitoring procedures for each critical control points were established; verification procedures were also discussed.
A Simplified Improvement on the Design of QO-STBC Based on Hadamard Matrices  [PDF]
K. O. O. Anoh, Y. A. S. Dama, R. A. A. Abd-Alhameed, S. M. R. Jones
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2014, DOI: 10.4236/ijcns.2014.71005

In this paper, a simplified approach for implementing QO-STBC is proposed and evaluated with improved performance. It is based on the Hadamard matrix, in which the scheme exploits the Hadamard matrix property to attain full diversity. Hadamard matrix has the characteristic that diagonalizes a quasi-cyclic matrix and consequently, a decoding matrix so that a diagonal matrix which permits linear decoding is achieved. Using quasicyclic matrices in designing QO-STBC systems requires that the codes should be rotated to reasonably separate one code from another such that error floor in the design can be minimized. It will be shown that, orthogonalizing the secondary codes and then imposing the Hadamard criteria of the scheme can be well diagonalized. The results of this simplified approach demonstrate full diversity and better performance than the interference-free QO-STBC. Results show about 4 dB gain with respect to the interference-free QO-STBC scheme and it performs alike with the earlier Hadamard based QO-STBC designed with rotation. These results achieve the consequent mathematical proposition of the Hadamard matrix and its property is also shown in this study.

Does occupational exposure to low-dose ionizing radiation affect bone marrow thrombopoiesis?
Douaa Sayed, Mostafa E Abd Elwanis, Saly Y Abd Elhameed, Hanan Galal
International Archives of Medicine , 2011, DOI: 10.1186/1755-7682-4-8
Abstract: In order to assess the risk of this exposure on BM thrombopoiesis, we measured reticulated platelets (RP) by flow cytometry in 14 hospital workers (12 technicians and 2 nurses) exposed to low level ionizing radiation in Radiotherapy Department in South Egypt Cancer Institute.There are significant difference in the percentage of RP in the peripheral circulation of the workers (p = .008) and no significant difference in the proportion of other blood elements in the peripheral circulation.We think that measuring RP by flow cytometry is a rapid, non-invasive method to asses an early affection of thrombopoiesis. This type of monitoring may be used as an indicator to detect early BM affection and to demand more controls in radiation protection.Evaluation of thrombopoiesis by quantifying reticulated platelets (RP) has been described [1,2]. RP by analogy to reticulocytes, are the youngest circulating platelet population and they contain abundant amounts of mRNA. RP were first described in 1969 [3] by direct visualization from peripheral blood. In 1990, Kienast and Schmitz reported the first measurement of RP by flow cytometry. RP measurement is a non-invasive test that provides indirect information about thrombopoietic activity in bone marrow [4].A chronic radiation dose is a relatively small amount of radiation received over a long period of time. The body is better equipped to tolerate a chronic dose than an acute dose. The body has time to repair damage because a smaller percentage of the cells need repair at any given time. The body also has time to replace dead or non-functioning cells with new, healthy cells. This is the type of dose received as occupational exposure [5].The toxicological effects of high levels of radiation exposure are fairly well known, but the effects of low levels of radiation are more difficult to determine because the deterministic effects do not occur at these levels [5].Since deterministic effects do not generally occur with chronic dose, in o
Molecular Characterization of Chicken Anemia Virus Circulating in Chicken Flocks in Egypt
Mohammed AboElkhair,Alaa G. Abd El-Razak,Abd Elnaby Y. Metwally
Advances in Virology , 2014, DOI: 10.1155/2014/797151
Abstract: Introduction. Although many previous studies reported detection of chicken anemia virus (CAV) in Egypt since 1990, genomic characterization of this circulating CAV has not been published. In the present study, four nucleotide sequences of detected CAV were genetically characterized. Methods. These nucleotide sequences were obtained from commercial chicken flocks in two different locations of Egypt during 2010. The target region for sequencing was 675?bp nucleotide of partial coding region of VP1 protein. The nucleotide and deduced amino acid sequences of the detected CAV were aligned and compared to worldwide CAV isolates including commonly used vaccine strains. Phylogenetic analysis of these sequences was also carried out. Results. Our results showed that all the Egyptian CAV sequences were grouped in one group with viruses from diverse geographic regions. This group is characterized by amino acids profile 75I, 97L, 139Q, and 144Q in VP1. The phylogenetic and amino acid analyses of deduced amino acid indicated that the detected CAV sequences differ from CAV vaccine strains. Conclusion. This is the first report that describes molecular characterization of circulating CAV in Egypt. The study showed that the detected CAV, in Egypt are field viruses and unrelated to vaccine strains. 1. Introduction Chicken anemia virus (CAV) is an economically important pathogen with a worldwide distribution. CAV is a small DNA virus with a closed circular, negative, single stranded DNA genome. It belongs to genus Gyrovirus of family Circoviridae [1]. The genome consists of three partially overlapping open reading frames encoding three viral proteins: VP1 (51.6?kDa), the major viral capsid protein, VP2 (24?kDa), a novel dual specificity protein phosphatase [2] that also probably acts as scaffolding protein during virion assembly [3], and VP3 (13.6?kDa), also called apoptin, which has been shown to have apoptotic activity in transformed cell lines [4]. VP1 shows the highest nucleotide variability; therefore, it is usually used for genetic characterization and molecular studies of CAV [5, 6]. Infection with CAV constitutes a serious economic threat, especially to the broiler industry and the producers of specific pathogen free (SPF) eggs. The clinical signs are mainly noticed in young chicks of 10–14 days of age, which acquire the infection vertically. Chickens older than 2-3 weeks of age are also susceptible to infection but only develop a subclinical disease evidenced by poor vaccine response [7]. The disease is characterized by aplastic anemia and generalized lymphoid
Page 1 /52555
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.