Digital Repository for University of Tripoli

Abstract

The search for a reliable source of energy has been a challanging task to manking while conventional energy resorces are diminishing nuclear fusion, especially laser fusion, promises to be the source of the future. Experimental costs in laser fusion are astronomical and computer modeling drastically minimizes such costs and gives a chance for less fortunate Gauntries to gain insight into the scientific and technical aspects of the subject since a large portion of information involved is classified. This work deals with the spatial and temporal evolution of the laser fusion produced by different laser pulses It is based on a computer code called MEDUSA which takes into account the variation in the wavelength, power density pulse duration, target geometry and material. It assumes a target which is divided into 20 cells each of 24 urn width. Inverse-Bremsstrahlung and resonance absorption are the two main mechanisms responsible for absorption of energy from the incident laser pulse. Fusion takes place in the plasma as a result of ablation of the plasma corona where the formed shock waves compress the plasma cells and heat them. The rate of energy deposited into and radiated from the plasma ,which causes variation of the plasma internal energy, is expressed by the energy equation. This equation is transformed into a finite difference form and solved by Gauss Elimination Method to calculate the plasma parameters such as electron(T e) and ion ternperatures(Ti), pressure(P) and density(p) and the different processes of energy absorption and losses. The temporal evolution of these parameters is studied through the divisions of the pulse into chosen time steps at which the evolution is clear. The results have shown that by increasing laser power the energy deposited into and radiated from the plasma increases. The electron and ion temperatures the plasma pressure and density also increase. This is because of the geadual propagation of the shock wave from the surface of the pellet towards its center causing compression of the plasma cells. The optimum value of such parameters are obtained close to the end of the pulse where the incident laser power is maximum and so as the energy deposited into the plasma center where heating and compression causes the consumption of the whole target After the end of the pulse duration, the plasma cells coordinates expand and the plasma parameters decrease, a process known as diminishing of the plasma The effect of the laser parameters of four diffterent lasers namely CO2, KrF, Nd-glass and Ruby of 5ns, 15ns and 45ns pulse duration was studied. It was found that: (1) the maximum value of the plasma parameters decrease by increasing the pulse duration of a certain power and wavelength, (2) the maximum value of the plasma parameters increase by increasing the wavelength because of increasing the energy deposited into the plasma by resonance absorption process. At the optimum implosion time, the plasma parameters show a strong spatial variation. However, a strong temporal variation of the plasma parameters was observed at the pellet center.
هناء محمد حسن موسي (1994)

Abstract

The Sirt Basin is one of the youngest sedimentary basins in Libya and covers an area of approximately 600.000 km² in north central Libya. It is located on the northern margin of the African plate, with approximate coordinates 14°00`- 20°00`E and 28°00`-31°00`N. The Late Jurassic-Early Cretaceous as Sarir Sandstone in the Sirt Basin evolved as a consequence of the interplay between global eustasy and regional tectonics. As Sarir Sandstone of the eastern Sirt Basin is composed mainly of sandstones and shales resting unconformably on a basement complex of igneous and metamorphic rocks. It is unconformably overlain by the Upper Cretaceous sediments of Maragh, Lidam and Etel formations. It has been subdivided into three members. The upper member consists mainly of sandstones with intercalations of siltstones and shales of variable thickness. The middle member consists of shale and silty shale. The basal part of the formation, which rests directly on the crystalline basement represents the lower member. It is comprised of sandstone with subordinate intercalations of siltstones and shale. Two main facies have been recognized on the basis of lithological features and types of stratifications: which consist mainly of shale and intercalation of silt and sand. The Middle Shale Member consists mainly of shallow lake deposits, containing black shale facies. Continental Fluvial Deposits represent most of the cored interval and it belongs to the Upper as Sarir Sandstone. These facies have been subdivided into braided and meandering lithofacies: The braided depositional system, has been recognized in three different intervals of the studied cores; classified as subfacies (1), subfacies (2) and subfacies (3). The meandering depositional system, represents three sub-environments including point bars, abandoned channels and over-bank deposits. The reservoir characteristics of these sediments are studied on the basis of porosity, permeability and reservoir zonation. The reservoir quality of As Sarir Formation is largely controlled by primary sedimentary features associations, which were shaped by the depositional environments. Meandering Lithofacies are formed from continuous sand successions and show good porosities, up to 18.51%, and permeabilities up to 125.5mD. The Braided Lithofacies also show good reservoir quality, but the effective porosity and permeability are lower, because of associated shales. The most important diagenetic features responsible for a reduction in reservoir quality are those resulting from compaction, cementation, and the diagenesis of clay minerals.
صلاح الدين محمد الوحيشي (2014)

Abstract

The static behavior of large deflection of plates is considered. The w-F governing equations for large deflection of plates are derived and Solved using Finite Element with Galerkin approach to calculate the static deflection and for parameter values which span the design space. An Incremental Iterative technique were used. The Galerkin Method was used to derive the element stiffness matrix and load victor. A three node- 18DOF Triangle Element was selected to calculate the nodal field variables. Two boundary conditions were considered, the simply supported and clamped plates. A well prepared program used for plates with small deflection,, Linear Problem,, was modified to handle the changes in the governing equations and apply the solution techniques. A good fit with previous published studies was found.
القاسم محمد كامور (2009)

Abstract

The study area is located in and around Umm Ar Razam village, about 50 Km east of Darnah city, north-eastern Libya. In this study many claystone sections were studied. These claystones belong to the lowermost part of Al Faidiyah formation of Upper Oligocene – Lower Miocene age. The studied sections consist of claystone beds ranging in thickness about 10 meters. These bentonitic clays are generally grey to greenish grey in colour, with popcorn – like appearance. They have a waxy character and are exposed sporadically in this area as isolated outcrops. They might be deposited in lagoonal, lacustrine or shallow marine environment. The main purpose of this thesis is to study the origin and to evaluate the Umm Ar Razam bentonitic clays. For example, lithology, mineralogy, the chemical composition, crystal forms and habits, physical properties, industrial uses and treatment will be investigated. The Results showed that these clays consist of the minerals Na- montmorillonite, Kaolinite, and Illite. Non – clay minerals includes quartz, calcite, dolomite, gypsum, halite, muscovite, rutile, sanidine, and tridymite. Moreover, clay mineral fraction studies using the different techniques showed that these bentonitic clays were formed due to in situ alteration of volcanic ash in subaquous environment. Evidences for such an occurrence include mineralogical evidence as the existence of high temperature minerals as sanidine, rutile, and tridymite. The existence of unaltered volcanic ash as seen from SEM photomicrographs also supports this origin. Furthermore, XRF results showed downward depletion of silica right below these bentonitic clays 6 in calcarenite beds of Al Abraq formation. XRF results also showed that the Umm Ar Razam bentonites are in accordance with the American bentonites and the parent material of such bentonites came from basic volcanic ash materials. In addition, the viscosity and the filtration of Umm Ar Razam bentonite is nearly identical with the international bentonite by adding (Soda Ash) and (Na2 SiO3 ) with special treatment method. The cost of the Enhanced Umm Ar Razam bentonite is less than of the imported bentonite cost. Based on the physical and chemical properties these bentonites can be used in many industries especially as building materials and drilling fluids.
فيصل عياد أبو سهمين (2009)

Abstract

The success of projects are depends on the people involve and how they tackle the design of the projects for specific needs, planning of activities, budget cost and execution to achieve the ultimate goal. Each phase of the project contributes an important task and this will reflect on how good the project management handled by the team.Project management means managing all the relevant activities of the project within the given constraints of time and cost, however , to complete specified project as per schedule and within the allocated budget, an accurate planning and optimization of all available resources will be required to complete all the tasks.During the projects, changes can occur even though the original scope may have been carefully planned. These changes might occur at any times and in ways that are unexpected.Changes during project execution can significantly affect not only time schedule but may affect also the economical aspect of the project. This phenomenon can be considered as normal and experienced world wide especially in the third world countries wherein lack of technical knowledge and resources are major problems.This study concerns the majority of the managerial changes occurred during the project execution step and the role of the organization in handling such changes as competitive and finding solutions in order to manage the project effectively.Many oil companies in Libya were facing numerous problems in the delay of project implementation, poor quality management, planning and poor performance which deviate from the required project objectives. Changes that occur later in the implementation cause serious problems in delaying the project schedule and increasing costs, effectively are reducing the benefits of the project.By Appling the questionnaire that consists of 30 specific questions which have been distributed to 13 Companies under umbrella of National Oil Corporation (N.O.C). Eight out of thirteen companies were responded.The analysis of the data collected from submitted questionnaire has been analyzed using Microsoft Excel 2000. That allows simple setting and manipulation of the data collected.Statistical data and interviews on the respondent companies indicate the following items: Full dependency on the external contractors to fully execute the project implementation that leads to high cost of contracts (EPC contracts).Poor supervision leading to significant delay of the implementation of the project. (Specifically of E P contracts).The Project Implementation profile (PIP technique) has been used on this study to evaluate one of the project which had delay and some other related problems selected random as case study. The analysis covered all the factors for project implementation. Technical factor.Managerial factors.Controlling factors. In order to improve the project management for oil & gas companies listed in this research and to overcome such problems. This study recommends a good communication and coordination system connecting all local petroleum companies and providing data exchange which enables to minimize time, cost personnel and learn from mistakes.
زينب مختار المصري (2007)

Abstract

This research was an attempt to use the currently available activity coefficient methods with universal sets of parameters to simultaneously predict ternary liquid-liquid equilibrium data. The focus of this research was to calculate phase equilibrium data within fair error using set of Parameters obtained from the above-mentioned models. The significance of this work is to study the liquid-liquid phase equilibrium of the ternary system at several temperatures and to test the capability of the various equilibrium models to correlate these data. A series of liquid-liquid equilibrium measurements were performed by changing the composition of the mixture.The prepared mixtures were placed in the extraction vessel and stirred for 2 h and then left to settle for 4 h. Samples were taken by a syringe from both the upper phase and lower layers. Both phases were analyzed using gas chromatography equipped. Liquid-liquid equilibrium for the ternary system acetonitrile + benzene + n-heptane was measured at 298,313,333 K. The results were used to estimate the interaction parameters between each of the three compounds for the NRTL and UNIQUAC models as a function of temperature. The estimated interaction parameters were successfully used to predict the equilibrium compositions by the two models. The UNIQUAC equation was the most accurate model in correlating the overall equilibrium compositions of the studied system. NRTL models satisfactorily predicted the equilibrium compositions. In each of the mentioned the ternary system, the calculated and experimental data were compared. The root mean square deviation (RMSD) between the observed and calculated mole percent for NRTL, UNIQUAC was 1.44%, 1.35% for acetonitrile + benzene + n-heptane
عماد الدين محمد الزغداني (2014)

Abstract

This research was conducted in Agriculture Faculty Research Center/ El-Fatah University, Tripoli, Libya during 2006/2007 growing season. The objective was to study some morphological, physiological and anatomical characters associated with grain yield and drought resistance in some varieties and lines of barley developed by crossing and hybridization in Agriculture Research Center in Great Jamahiriya. Statistical analysis of the data showed significant differences between varieties and lines in main spikes length and number of spikes/plant .Moreover the differences between varieties and lines in length of main stem spike, total tiller number /plant and spike number/ plant were significant. Statistical analysis of data also showed that differences between varieties and lines in grain number of main spike, grain number of lateral spike, and mean grain weight /spike were significant. Data also showed that differences between varieties and lines in grain weight of main spike were not significant. However, differences between them in grain weight of lateral spike, and mean grain weight /spike were significant. This data also indicated that that there were significant differences in weight of 100 grains /plant, grain weight/plant and straw. In addition to this, harvest index for this varieties and lines was significantly different, and its value ranged between 59.9% and 70.9%. These results also showed that number of spikes/plant was the main grain yield component (r =0.76 p
سناء علي الشارف ابودينار (2009)

Abstract

this study aims to investigate the hydrological cycle at wadi Zaghadnah basin in Tarhuna in terms of (rainfall-surface run-off-evaporation-infiltration) and estimation of the quantity of surface water , and to predict the maximum flood can happen in order to reduce hazardous to houses and farms that are found on my profile of the valley was the use of a series of years of readings rainfall and results have indicated to the fact that annual average rainfall was (238) mm, via using (Isohyetal method).The quantity of water which is supposed to be reserved in the dam was (1.94) million cubic meters. As for rain test, it was found that it is random and non-coherent. Having studied rain-wave relation through application of modelprediction statistical, it was deduced that it is not reliable to depend-upon in forecasting the expected rain. Results have indicated that total evaporation average to (2324.5)mm via using (CROPWAT) and average annual infiltration is (2065.17)mm, and post application of some statistic equations like probability log-Pearson Type ׀׀׀distribution and Gumbels distribution-plotting (25-50-100-1000), maximum possible amount (via using the aforesaid three methods) was found, but due to silt and likely erosion of soils as a result of flooding, silt amounts in Dom lake was estimated by using calculative equations was (5622)m³/year.
عيادة محمد ميلاد اليونسى (2012)