Digital Repository for faculty of Engineering

Abstract

The DC motor drives one of the high performance drives that still in competition in industrial application, because of its high performance, robustness, and its lower cost compared with AC motor drives.Due to its majority applications, the separately excited DC motor driver is studied. In order to improve, three independent controller design using classical proportional - integral – derivative, linear quadratic regulator and artificial neural network are considered.The Performance of these controllers has been verified through simulation based on MATLAB/SIMULINK software tools. According to the obtained simulation results, it is found that, an artificial neural network can achieve a better transient and steady state response in comparing to the other two design method. Consequently, the superiority of ANN controller over conventional proportional - integral – derivative is demonstrated this shows the superiority of artificial neural network controller over conventional and linear quadratic regulator controllers.
.زينب إبراهيم علي (2014)

Abstract

The increased amount of electromagnetic radiation in the environment has increased the common concern over the possible health risks of wireless devices (e.g. mobile phone ). However, to minimize the amount of energy absorbed by the user is an advantageous from the technical point of view, as well. The reduction of power absorbed by the user not only reduces any possible health hazards but also makes the antenna more efficient. In this master’s thesis, interaction between modern mobile phone antennas and user is studied by using numerical full-wave EM methods. The thesis aims at improving, understanding how mobile terminal antennas behave in the vicinity of the user and how different numerical EM methods can be used to solve the interaction problem. The results give valuable information for antenna designers in order to design antennas which have low interaction with the user as possible. Furthermore this master’s thesis introduces a simple optimization technique to enhance the performance of planar inverted F antenna (PIFA) one of common modern mobile phone antenna in vicinity of user and reduce its effect on health.
محمد على المنصورى (2008)

Abstract

The industrial renaissance of the General Arab countries and the Libyan Arab country to make a special request to the elements and lounges stereochemistry of metal accessories and urgent, this renaissance that accompanied the technological revolution represented by using a computer and the diversity of its programs and the expansion of research methods and knowledge in various disciplines imposed on the engineers and industrialists and Almquaoliyn various categories of specialists, and that Ioakpo this international scientific development to be desired and decent level before this data. Where highlights of this research shed light on the installations steric mineral reviewing the characteristics of the analysis and structural design and methods of the basic implementation and relations of reciprocity between them and listed in a simple way and classified according to their constituent elements, to provide those interested in this field, among the main outlines of which need them in this special geometric way. Our goal in this research to the definition of mineral spatial installations, the basics of analysis, design and construction of major roads for this type of installations. Which we hope to contribute to simplify the development and understanding of the specific platform for this type of construction.
نبيل موسى الدليمي (2014)

Abstract

The objective of this study is to formulate a drilling cost model which incorporates the drilling parameters, encountered during drilling operation of the petroleum well. This model is coupled with the selected drilling rate model proposed by Bourgoyne & Young, in order to predict the bit rotating time utilized in this model. The new drilling cost model was formulated using actual drilling data collected from thirteen wells selected in three oil fields in Sirte Basin (Ghani, Zenad, and Ed Dib).The drilling engineer can use drilling correlations in the planning stages of a well to help evaluate various drilling parameters encountered during drilling operations in order to update the proposal drilling plan and to evaluate any deviations from original projections. The gathered information will help selecting the best completion strategies as well as gaining experiences in the drilled area which will be the basis for the planning of future drilling activities in the area.
عزالدين أحمد أحمد (2009)

Abstract

The quadruple-tank process has been widely used in control literature to illustrate many concepts in multivariable control, particularly, performance limitations due to multivariable right half-plane zeros. The main feature of the quadruple-tank process is the flexibility in positioning one of its multivariable zeros on either half of the‘s’ plane A nonlinear and linear dynamic model for the quadruple-tank process are derived. The nonlinear model is derived from Johansson nonlinear dynamic system and describes the complicated dynamics of the physical plant when the system is setting in the non-minimum phase. The simulation results show that PID controllers have acceptable performances especially when the system is minimum-phase system while in the non-minimum-phase the controller is poor. Also it is shown that the linear quadratic Gaussian with loop transfer recover (LQG/LTR) is better than PID controller when the system is minimum-phase while in the non-minimum-phase the controller is not acceptable because (LQG/LTR) compensators generally cannot be designed for non-minimum-phase plants. Simulation results show that the proposed Decentralized fuzzy logic controller has a remarkable performance for tracking the multi step reference trajectories while at the same time it is robust against voltage changes. The Simulation results confirm the effectiveness of the proposed control methodology.
أبوبكر عبدالكريم أبو شاقور (2010)

Abstract

The research discusses the passive solar energy in cooling the internal gaps, using architectural and urban techniques In the traditional architecture In Libya, aiming to reach to required thermal comfort for humans, particularly in the high temperature areas, It could be done through four chapters in the research, so that shall contain a part of the research content, in addition to results and recommendation, so that shell discuss: First chapter: whereas the research discusses the study of climate elements, which are considered as the most effecting factors on thermal comfort, plus demonstration of climate and climate regions in Libya. Thereafter, the study of traditional architecture in different regions of Libya (cost, mountains, desert), clarification of their most important characteristics and features at architect and urban levels, used materials and methods of construction of the same, then comparison of regions to reach to features of each region. Second chapter: this chapter shall discuss study of humans comfort, and sources of thermal gain and loss between the human body and its ambient, especially by climate factors, the most significant study of thermal gain and loss sources of the building form the direct sun rays, via walls and roofs and movement of the air. Third chapter: the sun rays are deemed the most important climate elements effecting the architectural and urban, which generate other climate elements, such as air movement and humidity …etc, which in turn impact the human thermal comfort. Thus, this chapter focused on study of passive cooling techniques, using urban and architectural technologies, to limit the effect of sun rays, prior to its reach to the building, or to limit its penetration through walls and roofs, passing by historical stops of using passive cooling techniques. Fourth chapter: Addresses this chapter analytical study applied to the methods and techniques of cooling using solar energy passive in traditional architecture, by examining and analyzing the most important of these techniques and treatments Urban and architectural in different regions (coastal, mountain, desert) and benefit from and applied in the local architecture. Finally: the search to a set of findings and recommendations to the effect that he must return to traditional architecture and technologies and processes and take advantage of them to maintain the legacies of urban and architectural history, and development in the local construction and architecture.
يوسف مفتاح الهمالي (2013)

Abstract

This Thesis overviews the methods for calculating the stress intensity factor and employs the stress and displacement methods in the current study. The model used simulates a cracked rectangular plate which is subjected to tensile stress. The Finite element method is used to calculate inplane displacement due to applied loads. As a post processing the stress and stress intensity factor over the plate was calculated. The results show that the singularity exists at the crack tip and the components of stress and approach infinity as the crack tip approach. The comparison of the current study to theoretical and other numerical results shows a good agreement and reliability of the program. The thesis consists of five chapters, the first chapter, presents general over view and historical al review. The second chapter demonstrates the theoretical basis in fracture mechanics. The third chapter involves the numerical solution using F.E.M. The fourth chapter demonstrates a case study and the results and discussion of the obtained results. The fifth chapter concludes the work and gives recommendations.
محمد كامل الشيخ (2009)

Abstract

Traditional compact urban fabric patterns is type of urban fabric that characterized by its organic structure integrated with the natural environment. The building blocks in this type are attached interspersed with interior courtyards within and between buildings. Streets and alleys are narrow, not straightforward and with closed endings. This system is common in the old traditional cities. Traditional compact urban fabric is classified according to the traffic network into forked or regular this research deals with the study and analysis of the concept of traditional compact urban fabric from the social perspective. It is a study of the social aspects affecting and affected by the built environment related to daily life within the prevailing social systems which is a man-made laws laid down by a group of people to organize their lives. Due to the multiplicity of the fields of social system, the researcher identified systems that are thought to have a clear impact on the built environment in the study area, which are the tribal system, the family system and the management of traditional community (Alhessbah and Aezzabah) The old town of Jadu was chosen as a case study. The study addresses the following issues. First- the concept and the characteristics of traditional compact urban fabric, were defined through the study of historical examples. Secondly - the physical structure of traditional compact urban fabric and the impact of social factors in the formation of this structure. Thirdly, field study which limited to the old town of Jadu which consists of two neighborhoods Tarkeen and Amgail. The porpose of field study is to analyze the impact of specific social systems on the built environment in the study area
نادية خليفة الحارس (2014)