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Search Results: 1 - 10 of 477257 matches for " Adel A. Al-Azzawi "
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Analysis of timoshenko beam resting on nonlinear compressional and frictional Winkler foundation
Adel A. Al-Azzawi
Journal of Engineering and Applied Sciences , 2011,
Abstract: This paper deals with linear elastic behavior of deep beams resting on linear and nonlinear Winkler type elastic foundations with both compress ional and tangential resistances. The basic or governing equations of beams on nonlinear elastic Winkler foundation are solved by finite difference method. The finite element method in Cartesian coordinates is formulated using two dimensional plane stress isoparametric finite elements to model the deep beam and elastic springs to model the foundation. Two computer programs coded in Fortran_77 for the analysis of beams on nonlinear elastic foundations are developed. Comparisons between the two methods and other studies are performed to check the accuracy of the solutions. Good agreement was found between the solutions with percentage difference of 3%. Several important parameters are incorporated in the analysis, namely, the vertical subgrade reaction, horizontal subgrade reaction and beam depth to trace their effects on deflections, bending moments and shear forces.
Finite difference analysis of curved deep beams on Winkler foundation
Adel A. Al-Azzawi,Ali S. Shaker
Journal of Engineering and Applied Sciences , 2011,
Abstract: This research deals with the linear elastic behavior of curved deep beams resting on elastic foundations with both compressional and frictional resistances. Timoshenko’s deep beam theory is extended to include the effect of curvature and the externally distributed moments under static conditions. As an application to the distributed moment generations, the problems of deep beams resting on elastic foundations with both compressional and frictional restraints have been investigated in detail. The finite difference method was used to represent curved deep beams and the results were compared with other methods to check the accuracy of the developed analysis. Several important parameters are incorporated in the analysis, namely, the vertical subgrade reaction, horizontal subgrade reaction, beam width, and also the effect of beam thickness to radius ratio on the deflections, bending moments, and shear forces. The computer program (CDBFDA) (Curved Deep Beam Finite Difference Analysis Program) coded in Fortran-77 for the analysis of curved deep beams on elastic foundations was formed. The results from this method are compared with other methods exact and numerical and check the accuracy of the solutions. Good agreements are found, the average percentages of difference for deflections and moments are 5.3% and 7.3%, respectively, which indicate the efficiency of the adopted method for analysis.
Behavior of ultra high performance concrete structures
Adel A. Al-Azzawi,Ahmed Sultan Ali,Husam K. Risan
Journal of Engineering and Applied Sciences , 2011,
Abstract: A study has been made through this investigation to understand the behavior of UHPC members with steel fibers by using two approaches: experimental investigation of concrete mixes and simulation of the problem studied by other researchers using finite elements. Experimental investigation is carried out to obtain the mechanical properties for two types of UHPC mixes, namely, the type of pozzolanic admixture (Silica Fume and High Reactivity Metakaolin) in addition to use three different values of steel fibers volume fraction (1%, 1.5% and 2%). The finite element method through the ANSYS computer program is used. The eight node brick element is used to model the UHPC beams with embedded steel fibers. The stress-strain curve in compression for the UHPC with steel fibers is simulated by a nonlinear elasto-plastic model which is terminated at the onset the crushing. In tension, a smeared crack model with fix orthogonal cracks has been used. The experimental data obtained from other researchers is compared with the finite element solution and good agreement between the results is obtained. Parametric studies are carried out to investigate the effects of type of pozzolanic admixture, volume fraction of steel fibers and other solution parameters. Higher values of compressive strength have been achieved using UHPC mixes with Silica Fume in comparison with UHPC mix with High Reactivity Metakaolin.
Simultaneous Bilateral Spontaneous Pneumothorax: Report of 6 Adult Patients  [PDF]
Ahmed I. Al-Azzawi
World Journal of Cardiovascular Surgery (WJCS) , 2015, DOI: 10.4236/wjcs.2015.52004
Abstract: Background: Spontaneous pneumothorax (SP) refers to the spontaneous presence of air in the pleural sac(s) without iatrogenic or traumatic factors. The simultaneous bilateral SP (SBSP) is rare yet serious clinical condition which may pose a significant threat to patient’s life. Herein, 6 patients with SBSP managed in Sulaimaniyah Teaching Hospital (STH) over 6-year period (2006-2011) are reported with literature review. Methodology: A prospective clinical study. The diagnosis was made on clinical and radiographic grounds. The initial therapy was a bilateral tube thoracostomy (BTT) followed by chemical pleurodesis. Thoracotomy for excision of subpleural blebs or bullae and pleurectomy was performed for prolonged air leak (lasting >14 days). Results: There were 5 males (83.33%) and 1 female (16.67%) with a mean age of 34.8 years ranging between 20 and 50. All patients had presented with dyspnea and chest pain and were smokers. Three patients (50%) had primary (PSP) whereas the remaining had secondary (SSP) (chronic obstructive pulmonary disease—COPD, n = 2 and pneumonia, n = 1). None of the patients had recurrence. Unilateral thoracotomy was necessary in 5 patients (SSP, n = 3 and PSP, n = 2). Prolonged air leak was observed once postoperatively (16.7%) while mortality was nil. Conclusions: Prompt recognition of this rare yet potentially serious condition is crucial. The clinical diagnosis is straightforward with plain chest radiography being the most helpful workup. The initial therapy is via BTT followed by pleurodesis. Surgery is necessary for prolonged air leak and failure of the lung to expand.
Extraction of Aspirated Headscarf Pins with Fiberoptic Bronchoscopy  [PDF]
Ahmed I. Al-Azzawi
World Journal of Cardiovascular Surgery (WJCS) , 2017, DOI: 10.4236/wjcs.2017.712016
Abstract: Background: Foreign body aspiration is a common yet preventable health problem. Headscarf pin aspiration is a unique example of aspirated foreign bodies in young Muslim women usually removed using the rigid bronchoscope. However, the flexible bronchoscope is increasingly used for this purpose. This prospective study was conducted in Sulaimaniyah Teaching Hospital, Sulaimaniyah, Iraq and aimed to evaluate the usefulness of fiberoptic bronchoscope for removal of aspirated headscarf pins in view of the relevant literature. Methodology: Fifty female patients with headscarf pin aspiration were managed by fiberoptic bronchoscopy over an 8-year period (January 2008 to December 2015). The procedure was performed under local anesthesia and conscious sedation through the mouth. Results: The age ranged from 10 to 45 years with a mean of 27.5. All patients had cough, five had unilateral wheeze (10%) while haemoptysis occurred twice (4%). Fiberoptic bronchoscopy succeeded in 45 cases (90%). Rigid bronchoscopy under general anesthesia was necessary in (n = 4, 8%) while one patient (2%) required thoracotomy. Conclusion: Fiberoptic bronchoscopy is safe and effective in removal of aspirated headscarf pins and should be tried first.
Control and Synchronization with Known and Unknown Parameters  [PDF]
Maysoon M. Aziz, Saad Fawzi Al-Azzawi
Applied Mathematics (AM) , 2016, DOI: 10.4236/am.2016.73026

In this paper, we consider the chaos control for 4D hyperchaotic system by two cases, known & unknown parameters based on Lyapunov stability theory via nonlinear control. We find that there are two cofactors that have an effect on determining any case to achieve the control, the two cofactors are proposed in the control and the matrix that produce from the time derivative of Lyapunov function. In adding, we find some weakness cases in Lyapunov stability theory. For this reason, we design with only one controller and perform a simple change in this control in order to recognize the difference between these cases although all of the controllers are almost similar.

Genotoxic and Cytotoxic Study of Tecoma stans Bignoniaceae
Amad M. Al-Azzawi
Pakistan Journal of Biological Sciences , 2012,
Abstract: Tecoma stans (Bignoniaceas) is a central and south American tree used for the control of diabetes. This plant is cultivated in Iraq. The dried leaves were soaked in ethanol and water separately for 3 days then filtered and dried. The genotoxic potential of Tecoma stans was studied by in vivo and in vitro system. This study examined the genotoxic activity of aqueous and ethanolic extracts on bone marrow cells from BALB/c mice through evaluation of mitotic index and chromosomal aberrations and cytotoxic effect of the two extracts on Mouse Embryo Fibroblast (MEF) cell line. No alteration in the total number of chromosomal aberrations or the number of cells with chromosomal aberrations observed and percentage of mitotic index at the concentrations tested remained unchanged. The higher concentrations used of the plant extracts had a cytotoxic effect on the MEF cell line. Both extracts had no significant clastogenic effect in vivo but showed cytotoxic effects on mouse embryo in vitro, caution should be exercised in the use of this substance as a medicine.
Network Multiple-Input and Multiple-Output for Wireless Local Area Networks
Hong Huang,Hajar Barani,Hussein Al-Azzawi
Computer Science , 2014,
Abstract: This paper presents a tutorial for network multiple-input and multiple-output (netMIMO) in wireless local area networks (WLAN). Wireless traffic demand is growing exponentially. NetMIMO allows access points (APs) in a WLAN to cooperate in their transmissions as if the APs form a single virtual MIMO node. NetMIMO can significantly increase network capacity by reducing interferences and contentions through the cooperation of the APs. This paper covers a few representative netMIMO methods, ranging from interference alignment and cancelation, channel access protocol to allow MIMO nodes to join ongoing transmissions, distributed synchronization, to interference and contention mitigation in multiple contention domains. We believe the netMIMO methods described here are just the beginning of the new technologies to address the challenge of ever-increasing wireless traffic demand, and the future will see even more new developments in this field.
Network Traffic Anomaly Detection
Hong Huang,Hussein Al-Azzawi,Hajar Brani
Computer Science , 2014,
Abstract: This paper presents a tutorial for network anomaly detection, focusing on non-signature-based approaches. Network traffic anomalies are unusual and significant changes in the traffic of a network. Networks play an important role in today's social and economic infrastructures. The security of the network becomes crucial, and network traffic anomaly detection constitutes an important part of network security. In this paper, we present three major approaches to non-signature-based network detection: PCA-based, sketch-based, and signal-analysis-based. In addition, we introduce a framework that subsumes the three approaches and a scheme for network anomaly extraction. We believe network anomaly detection will become more important in the future because of the increasing importance of network security.
Applications of Compressed Sensing in Communications Networks
Hong Huang,Satyajayant Misra,Wei Tang,Hajar Barani,Hussein Al-Azzawi
Computer Science , 2013,
Abstract: This paper presents a tutorial for CS applications in communications networks. The Shannon's sampling theorem states that to recover a signal, the sampling rate must be as least the Nyquist rate. Compressed sensing (CS) is based on the surprising fact that to recover a signal that is sparse in certain representations, one can sample at the rate far below the Nyquist rate. Since its inception in 2006, CS attracted much interest in the research community and found wide-ranging applications from astronomy, biology, communications, image and video processing, medicine, to radar. CS also found successful applications in communications networks. CS was applied in the detection and estimation of wireless signals, source coding, multi-access channels, data collection in sensor networks, and network monitoring, etc. In many cases, CS was shown to bring performance gains on the order of 10X. We believe this is just the beginning of CS applications in communications networks, and the future will see even more fruitful applications of CS in our field.
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