Scientific Journal of Applied Sciences of Sabratha University https://jas.sabu.edu.ly/index.php/asjsu <h2>Applied&nbsp; Sciences Biannual Peer Reviewed Journal Issued by Sabratha University</h2> en-US jas@sabu.edu.ly (د. طارق الصالح) ADEL@sabu.edu.ly (د . عادل الغابر) Sat, 27 Apr 2019 16:17:06 +0200 OJS 3.1.1.0 http://blogs.law.harvard.edu/tech/rss 60 NEW DERIVED CORRELATIONS FOR LIBYAN CRUDE OIL TO ESTIMATE BUBBLE-POINT PRESSURE https://jas.sabu.edu.ly/index.php/asjsu/article/view/27 <p>The key factor of all petroleum engineering calculation is the knowledge of the PVT (Pressure, Volume, Temperature) parameters, such as determination of oil and gas flowing properties, predicting production performance in the future, production facilities designing and enhanced oil recovery planning methods. Those PVT properties are ideally determined experimentally in the laboratory. However, some of these experimental data is not always available; consequently, empirical correlations are used to estimate them. Many researchers have been focusing on models for predicting reservoir fluid properties from the available experimental PVT data, such as reservoir pressure, temperature, crude oil API gravity, gas oil ratio, formation volume factor, and gas gravity. The present study compares between some of the available empirical PVT correlations for estimating the bubble point pressure of some Libyan crude oils based on 35 data point samples from different Libyan oil fields. In the second part of this study, a new correlation has been derived to predict the bubble point pressure using <strong><em>Eviews software</em></strong> and compares the output results of this new correlation with some derived correlations found in the literature using statistical analysis such as the Average Absolute Error (AARE). The results showed an AARE as low as 8.7%, for bubble point pressure estimated by this new derived correlation. These results are valid to compare to other driven empirical correlations that have been evaluated.&nbsp;</p> Mustafa Sharrad, Hamid Hakim Abd-Alrahman ##submission.copyrightStatement## https://jas.sabu.edu.ly/index.php/asjsu/article/view/27 Thu, 25 Apr 2019 00:00:00 +0200 IMPROVEMENT OF SHARARA CRUDE OIL FLOW USING POLYSTYRENE AND POLYDIMETHYLSILOXANE AS DRAG REDUCING AGENTS https://jas.sabu.edu.ly/index.php/asjsu/article/view/28 <p>In this study the applicability of the Libyan crude oil flow induced by improved lab pumping system was examined in order to evaluate the effect of adding polymeric materials of Polystyrene and Polydimethylsiloxane as drag reducing agents (DRA) on the flow of Sharara crude oil in the pipeline. The polymers are injected through a pumping system at different concentrations rounded between (10-100) ppm. Several experiments were carried out to determine the best concentration of polymer, which satisfied lowest drag force on of crude oil flow rate. Furthermore, the effect of additive concentration on the Viscosity(μ), friction factor (ƒ), percentage drag reduction (%DR) and the amount of flow increases (%FI) were determined. The results show that the activities of Polydimethylsiloxane for Drag reduction is higher than drag reduction for Polystyrene. However, the %DR is generally increased with increasing of polymer concentration for all tested additives. It is progressively increased with increasing Reynolds number (Re) at any specific concentration of the polymeric additives. The friction factor is well correlated with Reynolds numbers and polymer concentration according to the relation of the form ƒ= k Re<sup>a</sup>C<sup>b</sup>, the results showed good agreement between the observed values and the predicted ones.</p> Rabeeah H. Sultan, Abduelmaged B. Abduallah, Omar M. Sultan M. Sultan ##submission.copyrightStatement## https://jas.sabu.edu.ly/index.php/asjsu/article/view/28 Thu, 25 Apr 2019 22:39:34 +0200 DETERMINATION CONVENTIONAL ROCK PROPERTIES FROM LOG DATA & CORE DATA FOR UPPER NUBIAN SANDSTONE FORMATION OF ABU ATTIFEL FIELD https://jas.sabu.edu.ly/index.php/asjsu/article/view/29 <p>A reservoir is a subsurface rock that has effective porosity and permeability which usually contains commercially exploitable quantity of hydrocarbon. Reservoir characterization is undertaken to determine its capability to both store and transmit fluid. Petrophysical well log and core data, in this paper, were integrated in an analysis of the reservoir characteristics by selecting of three productive wells. The selected wells are located at Abu Attifel field in Libya for Upper Nubian Sandstone formation at depth varied form 12921 to14330 ft. The main aim of this study is to compare the laboratory measurement of core data with that obtained from well log data in order to determine reservoir properties such as shale volume, porosity (Φ), permeability (K), fluid saturation, net pay thickness. The plots of porosity logs and core porosity versus depth for the three wells revealed significant similarity in the porosity values. The average volume of shale for the reservoir was determined to be 22.5%, and average permeability values of the three wells are above 150 md, while porosity values ranged from 9 to 11%. Low water saturation 13 to 22% in the three wells indicates the wettability of the reservoir is water-wet.</p> Adel Alabeed, Zeyad Ibrahim, Emhemed Alfandi ##submission.copyrightStatement## https://jas.sabu.edu.ly/index.php/asjsu/article/view/29 Thu, 25 Apr 2019 22:41:37 +0200 THEORETICAL ANALYSIS AND GRAPHICAL REPRESENTATION OF THE SYSTEM CURVE FOR WATER PIPELINE CONNECTING ZAWIA DESALINATION PLANT WITH HARSHA TANKS https://jas.sabu.edu.ly/index.php/asjsu/article/view/30 <p>The flow of water within a pipeline system causes loss of energy due to friction effects. To overcome these losses, energy is added to the water through the pump. So, the right pump selection is important for providing the required flow rate. The first step to select a right pump for any pipeline system is calculating the performance curve of piping system, which is a graphical representation of the energy required to move a given flow rate through a piping system and is used to identify the characteristics of the system's pump. For this purpose, the system curve for the water pipeline connecting the main reservoirs of Zawia desalination plant to the sub-tanks in Harsha has been evaluated and represented graphically in H-Q curve of the selected pump. This water pipeline network consists of sets of pipes connected in parallel and series with a total length of 5 km. The system NPSHA at different water levels in the suction tank at the maximum system flow rate of 800 (m<sup>3</sup>/hr) has been calculated to ensure avoiding cavitations problem in the selected pump.</p> Abdulmenam A. Abdalla, Ali K. Muftah, Ahmed O. Amhamed ##submission.copyrightStatement## https://jas.sabu.edu.ly/index.php/asjsu/article/view/30 Thu, 25 Apr 2019 22:43:25 +0200 EVALUATION OF DEGRADATION EFFECT ON INTERCOOLED GAS TURBINE PERFORMANCE OPERATED IN FLEXIBLE MODE https://jas.sabu.edu.ly/index.php/asjsu/article/view/31 <p>This paper investigates the effect of type and level of degradation in industrial gas turbine components on its performance under flexible operation due to working as a back-up to renewable energy sources (RES). This investigation was carried out for a 2-shaft 100MW aero-derivative gas turbine with intercooler. Due to the influence of unpredictable nature of power produced by RES, power plants are now operating in a flexible manner, which will require the operator to either stop operation during high feed-in from renewables or reducing the power output from the power plant to a certain percentage. This in turn has an impact on the gas turbine performance and thermal efficiency, which is also affected by the type and level of degradation of their components compared to the non-degraded gas turbines. In-House performance simulation software (TURBOMATCH), which was developed in Cranfield University, was used to carry out gas turbine performance modelling according to daily flexible operation scenarios for all seasons. These daily operating scenarios, which describe the power settings and ambient conditions for a period of 24 hours, were developed from data obtained from the UK national grid and the meteorology office data base. Different levels of degradation in mass flow and efficiency for low-pressure compressor and high-pressure turbine were applied in this study. Results illustrate an obvious impact of degradation type and level on fuel flow, turbine entry temperature, blade cooling temperature, shaft rotational speed and thermal efficiency for different seasons. This study has resulted in a tool which may be useful to power plant operators in understanding the various operating scenarios according to the criteria they wish to choose.</p> Siddig Dabbashi, Tarak Assaleh, Asia Gabassa ##submission.copyrightStatement## https://jas.sabu.edu.ly/index.php/asjsu/article/view/31 Thu, 25 Apr 2019 22:45:55 +0200 AN EXPERIMENTAL STUDY OF THE HERSCHEL-QUINCLE (HQ) TUBE NOISE ATTENUATION PERFORMANCE https://jas.sabu.edu.ly/index.php/asjsu/article/view/32 <p>The work presented in this paper summarize both analytical and experimental investigations of the Herschel-Quincke (HQ) concept for reducing known radiated inlet noise using signal generating system.&nbsp; The analytical part of this work involves one-dimensional plane wave propagate in a cylindrical duct. In this paper adaptive HQ tube is used to reduce tonal noise propagating as plane waves in closed end duct. The effect of HQ tube length on the noise reduction, induced by a loudspeaker at various frequencies, is investigated experimentally in an acoustically cylindrical duct with and without HQ. Five HQ tubes with different lengths are investigated. The distance between the HQ tube ends is kept constant (l=20 cm), ( &nbsp;= 1.5, 2.5, 3, 3.5, and 4). Two Microphones system was used to measure the net acoustic power transmission in the duct. One microphone is located just before the HQ tube in the duct, and the other is at the closed end of the duct where it is always anti-node pressure. Data acquisition, monitoring and analysis are done using National Instrument DAQ card and LabVIEW software.&nbsp; A LabVIEW vi code is developed to interface and process the two microphones system signals. Results showed that the length of the HQ tube is very important for a passive control of the noise reduction. While long HQ tube was effective in noise reduction in low frequencies, short HQ tube was more effective for high frequencies.</p> Abdul-Hafid El-Majani, Mohamed S. Oun, Salem A. Farhat ##submission.copyrightStatement## https://jas.sabu.edu.ly/index.php/asjsu/article/view/32 Thu, 25 Apr 2019 22:47:42 +0200 THE CONCEPT OF SUSTAINABILITY FROM AN ARCHITECTUIRAL VIEW https://jas.sabu.edu.ly/index.php/asjsu/article/view/33 <p>Libya is considered a virgin land for sustained development, and with its small population, the country’s productivity and consumption are still insignificant.&nbsp; Libya’s architectural heritage, which remains untainted by the pollution problems which plague more industrial countries. &nbsp;The most important problems facing the country are desertification and limited water supply. The failure of the Libyan State to enact laws to address these problems has contributed to their increase.</p> <p>This article deals with the concept of sustainability and its relation to the architecture science and its intellectual and cultural dimensions. In addition, the local efforts in Libya that aim to set up a local plan for coping with the international efforts and the resulting work rules regarding this concern. The researcher used the literature review as a method to focus on the pervious points. This study arrived at an important recommendation that the Libyan authorities should focus on the importance of developing educational curricula especially in the field of architectural engineering and urban planning so as to cope with the theories and principles of sustainable architecture.</p> Mariam M Shibub ##submission.copyrightStatement## https://jas.sabu.edu.ly/index.php/asjsu/article/view/33 Thu, 25 Apr 2019 22:50:38 +0200 تأثير السيليكا فيوم على خواص الخرسانة عالية المقاومة https://jas.sabu.edu.ly/index.php/asjsu/article/view/34 <p style="direction: rtl;">لقي استخدام الخرسانة عالية المقاومة اهتماما كبيراً في الآونة الأخيرة؛ لأن استخدام الخرسانة عالية المقاومة يقلل من القطاعات الخرسانية وبالتالي يوفّر مساحات فضاء أكبر داخل المنشآت، ويقلل من وزن المنشأ، ويسمح بزيادة عدد الأدوار، مع تميزها أيضاً بالديمومة والمتانة العالية وقدرتها العالية على التحمل مع الزمن.</p> <p style="direction: rtl;">في هذا البحث تمت دراسة تأثير اضافة السيليكا فيوم بنسب (20,15,10%) من وزن الأسمنت على خواص الخرسانة عالية المقاومة، ولما كان من الضروري للحصول على خرسانة عالية المقاومة خفض نسبة الماء للأسمنت تم استخدام نسبة ماء للأسمنت (0.30) وتم استعمال الملدن (بلاستوكريت- إن) بنسبة (3.5%) من وزن الأسمنت للمحافظة على قابلية التشغيل المطلوبة.</p> <p style="direction: rtl;">تم إجراء بعض الاختبارات على الخلطات والعينات الخرسانية وهي اختبار الهبوط واختبار مقاومة الضغط لعدد 84 عينة للأعمار (56, 28, 14, 7 يوم) واختبار مقاومة الشد غير المباشر لعدد 21 عينة بعد 28 يوم واختبار نسبة الامتصاص للخرسانة لعدد 8 عينات. وأظهرت نتائج الاختبارات تحسين جميع خواص الخرسانة عند إضافة السيليكا فيوم مقارنة بالخلطة المرجعية، وكانت أعلى مقاومة ضغط تم الحصول عليها بعد 56 يوم هي (87.8MPa) وذلك عند إضافة السيليكا فيوم بنسبة 15 %، وعند النسبة نفسها زادت مقاومة الشد على الخلطة المرجعية بنسبة (16.19%) بعد 28 يوم.</p> نوري محمد الباشا, مسعود حركات ارحومه, حسن محمد الحديدي ##submission.copyrightStatement## https://jas.sabu.edu.ly/index.php/asjsu/article/view/34 Thu, 25 Apr 2019 22:52:02 +0200 حصر وتعريف الطحالب البحرية بشاطئ منطقة صبراتة على الساحل الغربي من ليبيا https://jas.sabu.edu.ly/index.php/asjsu/article/view/35 <p style="direction: rtl;">الدراسة الأوليّة التي أجريت على الساحل الغربي من ليبيا بمنطقة صبراتة خلال فصلي الربيع والخريف 2015. كان مجموع الطحالب المسجلة 78 نوعاً، الطحالب الخضراء المزرقة 3 أنواع، الطحالب الخضراء 19 نوعاً، الطحالب البنية 20 نوعاً والطحالب الحمراء 36 نوعاً. مؤشر R/P 1.8، C/P 0.95 وR+C/P 2.75.</p> <p style="direction: rtl;">حيث تمَّ تسجيل وجود 52 جنس و78 نوع، منها 23 جنس، 36 نوع من الطحالب الحمراء، 12 جنس، 19 نوع من الطحالب الخضراء، 14 جنس، 20 نوع من الطحالب البنية، 3 أجناس، 3 أنواع من الطحالب الخضراء المزرقة.</p> هناء المهدي أبوحبيل, عمر أحمد الشتيوي, أمل الطاهر النّعاس, عمر أحمد التومي, ابتسام حسين بنوبة, زهور عيسى عمر ##submission.copyrightStatement## https://jas.sabu.edu.ly/index.php/asjsu/article/view/35 Thu, 25 Apr 2019 22:55:15 +0200 كسر طور السكون الغلافي لبذور الخروب وبذور الطلح باستخدام حمض الكبريتيك المركز لفترات زمنية مختلفة https://jas.sabu.edu.ly/index.php/asjsu/article/view/36 <p style="direction: rtl;">بذور الخروب والطلح تعرف بأنها تحتوي على قشرة سميكة تمنع تشرب الماء وتبادل الغازات، بصورة عامة سكون البذور الناتج عن صلابة القشرة يحدث في أنواع النباتات المتأقلمة مع مناخ المناطق الجافة والرطبة مثل شمال أفريقيا.</p> <p style="direction: rtl;">يهدف البحث إلى دراسة كسر طور السكون الغلافي في بذور كل من الخروب <em>Ceratonia</em> <em>sillqua</em> والطلح <em>Acacia</em> <em>tortilis</em> والتي تم تجميعها من مدينة الزنتان ومنطقة سهل الجفارة حيث ثم معاملتها بحمض الكبريتيك المركز على فترات زمنية مختلفة (10-20 و30 دقيقة).</p> <p style="direction: rtl;">أوضحت نتائج معاملة بذور نبات الخروب أن أكثر الطرق فعالية في كسر طور السكون للبذور كانت المعاملة لمدة 10 دقائق حيث أعطت أعلى نسبة إنبات وهي 95% أما زيادة مدة المعاملة حتى 30 دقيقة أدى إلى النقص في نسبة الإنبات حتى 24% وهذا راجع إلى تأثير الحمض على حيوية جنين البذرة.</p> <p style="direction: rtl;">أما بخصوص بذور نبات الطلح أظهرت نتائج الدراسة أن النقع بحمض الكبريتيك المركز لمدد زمنية مختلفة (10-20-30 دقيقة) أعطت نسبة إنبات تراوحت ما بين 61% , 64% و66% على التوالي وأنه لا يوجد فروق دالة إحصائية بين الفترات الزمنية.</p> رمضان سالم أحمد, الشتيوي امحمد امسيلخ, عبد الحميد عمران الشُقلاف ##submission.copyrightStatement## https://jas.sabu.edu.ly/index.php/asjsu/article/view/36 Thu, 25 Apr 2019 22:58:01 +0200 خصائص فريق التصميم وأثرها على تصميم المباني الخضراء في ليبيا https://jas.sabu.edu.ly/index.php/asjsu/article/view/37 <p style="direction: rtl;">استدامة البيئة العمرانية تلعب دوراً مهمّا في تحقيق الاستدامة بشكل عام، وتعدّ مرحلة التصميم هي أهم مراحل المشروع، وفريق التصميم اللاعب الرئيس في هذه المرحلة، وتكمن مشكلة البحث في تدني مستوى مخرجات تصميم المباني الخضراء في ليبيا، كما يهدف البحث إلى دراسة خصائص فريق التصميم وأثرها على مستوى مخرجات تصميم المباني الخضراء في ليبيا، ومن خلالها تحديد مستوى أداء فريق التصميم والصعوبات التي تواجهه أثناء عمليات تصميم المباني الخضراء. اتّبعت الدراسة منهجية التثليث في البحث؛ حيث بدأت بالدراسات السابقة، ثمّ مرحلة تجميع البيانات باستخدام الاستبيان ثم إجراء المقابلات الشخصية لتأكيد النتائج وتعميق الاستنتاجات. اُستُخدم برنامج SPSS للتحليل الإحصائي. من الدراسات السابقة تم التأكيد على متغيرات خصائص فريق التصميم للمباني الخضراء. كما أظهرت نتائج الدراسة مستوى متوسط للخصائص العامة، وتدني كبير في الخصائص الخضراء. كما استُنتجت الصعوبات التي تواجه فريق التصميم عند تصميم المباني الخضراء في ليبيا، وخُتمت الدراسة ببعض التوصيات التي من شأنها تحسّن أداء فريق التصميم.</p> مـحمد الصغير الفرجاني, عبد الباسط مـحمد الفيتوري ##submission.copyrightStatement## https://jas.sabu.edu.ly/index.php/asjsu/article/view/37 Thu, 25 Apr 2019 00:00:00 +0200