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Assessment of the impact of a 10-MW grid-tied solar system on the Libyan grid in terms of the power-protection system stability

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Clean Energy 2023年第2期7卷 389-407页

作者： Feras Alasali Abdelaziz Salah Saidi Naser El-Naily Othman Alsmadi Mohamed Khaleel Ibrahim Ghirani Department of Electrical Engineering Faculty of EngineeringThe Hashemite UniversityPO Box 330127Zarqa 13133Jordan Department of Electrical Engineering King Khalid UniversityAbha PO Box 394Abha City 61411Saudi Arabia Universitéde Tunis El Manar Ecole Nationale d’Ingénieurs de TunisLaboratoire des SystèmesÉlectriquesTunisie Electrical Engineering Department College of Electrical and Electronics Technology-BenghaziBenghaziLibya Electrical Engineering Department Faculty of EngineeringThe University of JordanAmmanJordan Aeronautical Engineering Department College of Civil Aviation MisrataLibya

The energy market in Libya is expected to face substantial changes in the next few years:electrical energy consumption will increase by 50% within the next 4 ***,there is a plan to gradually increase renewable energy sources in the power network by 2030 to 30%.Solar photovoltaic(PV)plants will play a significant role in the energy transition and the mix of energy sources in *** article is a study conducted to investigate the challenges of power-flow management and power protection from integrating PV power plants into the Libyan power *** particular,a simulation model is built for the Kufra PV power plant(10 MW)with eight buses to assess the power network performance in terms of power quality such as voltage profile,power losses and ***,the impact of the PV plant on the short-circuit level and the power-protection system is presented under different operating *** fault ride-through(FRT)is operated using standard ambient temperature and a wide range of irradiation intensity,and is verified by using the Libyan grid *** results show that the integration of the PV plant into the grid has a significant impact on the short-circuit level and the FRT over the different fault levels and locations on the *** initial period of the three-phase fault shows that the PV plant will be disconnected from the grid due to a decrease in the root mean square value voltages where the reactive and active power of the grid reach 938 MVAR and 261 MW,*** results show that increasing the fault level will lead to an increase in injecting the active *** work is considered the first extensive investigation into the challenges of modern power-flow management and power protection for the power network system in Libya.

关键词： photovoltaic renewable energy sources power protection voltage profile fault ride-through

Demography of the threatened endemic shrub, Arbutus pavarii,in the Al-Akhdar mountainous landscape of Libya

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Journal of Forestry Research 2016年第6期27卷 1295-1303页

作者： Hanan F.Kabiel Ahmad K.Hegazy Lesley Lovett-Doust Saud L.Al-Rowaily Abd EI-Nasser El Borki Department of Botany and Microbiology Faculty of ScienceCairo University Giza 12613 Egypt Department of Biology and Chemistry Nipissing UniversityNorth Bay ON Canada Department of Plant Production College of Food and Agricultural Sciences King Saud University Riyadh SaudiArabia Department of Botany Faculty of Science University of Benghazi Benghazi Libya

We sampled twenty populations of the vulnera- ble endemic shrub or tree, Arbutus pavarii Pampan., at different elevations and aspects within the A1-Akhdar mountainous region of Libya. Our sampling sites were at elevations ranging from 285 to 738 m above sea level, and several different habitats： vallies （locally known as wadis）, north- and south-facing slopes, and mountaintops. All individuals within each quadrat were studied. Population size and structure, and plant functional traits were assessed. None of the populations had a stable distribution of size classes. Some consisted mostly of small plants, with little or no fruit production; others consisted only of mid-sized and large plants, with high fruit production, but no juvenile recruitment. There was a significant increase in percent cover with increasing elevation; reproductive output （the number of fruits per branch and total number of fruits per individual） also generally increased with elevation. In some of these populations the lack of recruitment, and in others the failure to produce fruit, together constituted serious demographic threats. In light of these results, recommen- dations are made for conservation of this vulnerable endemic species.

关键词： Al-Akhdar mountains Conservation Demography Elevation Functional traits Vulnerable species

Daily, monthly and annual thermal performance of a linear Fresnel reflector to drive an organic Rankine-cycle system

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Clean Energy 2021年第4期5卷 673-689页

作者： Hassan Mahmood Khaled Hossin Mechanical and Construction Engineering University of NorthumbriaNewcastle upon TyneUK Mechanical and Industrial Engineering Department American University of Ras Al KhaimahRas Al KhaimahUnited Arab Emirates Mechanical Engineering Department University of BenghaziBenghaziLibya

The organic Rankine cycle(ORC)coupled with a linear Fresnel reflector(LFR)utilizes a low-grade heat *** article presents the study of a small-scale LFR-ORC power-generation plant under the climatic conditions of Almatret,*** mathematical modelling is performed using thermodynamic equations and simulations are conducted to evaluate the optical performance of the LFR system and thermal performance of the ORC ***-62 is used as a heat-transfer fluid(HTF)in the solar field,whereas NOVEC^(TM) 649 is used as the working fluid in the ORC power *** LFR is integrated with a thermal-storage unit based on a two-tank system and stores the solar thermal energy via a heat *** thermal-energy output of the receiver tube of the LFR system is 108 kW and thermal losses are 7.872 kW during the peak time operation of a day at 1:00 *** mechanical power output of the ORC turbine is 7.296 kW using the specific design conditions and the two-tank thermal-storage system adds 4 operation hours to the power plant after sunset.

关键词： solar energy linear Fresnel reflector energy storage organic Rankine cycle

Market Orientation and Libyan Tourism Business＇ Performances： A Comparative Study Between Public and Private Sector

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Economics World 2014年第2期2卷 124-136页

作者： Sabri G. M. Elkrghli university of benghazi Benghazi Libya

This paper aims to achieve these key objectives: (1) to measure the extent to which Libyan tourism businesses embrace the market orientation concept; (2) to evaluate the private and public tourism businesses" performance; (3) to identify the link between market orientation and tourism businesses" performances; and (4) to test the influence of ownership and organisational positions on market orientation-business performance relationship. A number of 582 questionnaires were distributed to high-level executives and clerks in tourism businesses in Libya. The key finding is that there is a growth in market orientation adoption. The performance of the private businesses is judged to be much better than the public one. There is a positive correlation between market orientation and tourism businesses" performance. This link is much stronger in the private sector. The market orientation in tourism sector is a critical element to drive business performance even in the less competitive environment such as Libya. The value of the paper is that it is the first paper to focus on market orientation in tourism sector in Libya. Therefore, the paper enriches the marketing literature with findings from the Arabic and North African region. Practically, the paper demonstrates the importance of market orientation to improve the Libyan tourism sector performance. Hence, international businesses, Libyan Government, tourism sector managers and employees should benefit from the results of the study. The paper concludes with limitations and future researches.

关键词：世界经济政策规划经济问题

Colorectal Cancer Implantation Metastasis in Haemorrhiodectomy Wound, Case Report

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Open Journal of Gastroenterology 2019年第9期9卷 185-191页

作者： Manal Algallai Mohamed Moftah Muftah A. Manita Soad I. Eldruki Department of General Surgery Benghazi Medical Centre Benghazi State of Libya Department of General Surgery Benghazi Medical Center Benghazi University Benghazi State of Libya Department of Radiology Benghazi Medical Center Benghazi University Benghazi State of Libya Department of Pathology Benghazi Medical Centre Benghazi State of Libya

Implantation metastasis from colorectal cancer into haemorroidectomy wound is very rare. The management of this condition remains controversial. We report a case of 68-year-old man with perianal soft tissue lesion biopsied and histopathology revealed an adenocarcinoma. Further investigation by colonoscopy and computed tomography scan revealed rectal adenocarcinoma. Pathological examination confirmed that this lesion was a distant metastasis from rectal cancer. The case was discussed at the multidisplinary meeting and the patient was advised to undergo long course neoadjuvant chemoradiotherapy followed by anterior resection and local excision of perianal metastasis. This case will be treated with long course neoadjuvannt chemoradiotherapy and after six weeks from treatment completion the plan is to perform sphincter sparing anterior resection and local excision of perianal implanted tumor.

关键词： Colorectal Cancer Haemorrhiodectomy Wound

Metal-Semiconductor Interfaces Investigated by Positron Annihilation Spectroscopy

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World Journal of Condensed Matter Physics 2016年第2期6卷 68-74页

作者： Abdulnasser S. Saleh Department of Physics University of Benghazi Benghazi Libya

Variable-energy positron annihilation spectroscopy has been applied to study interfaces in Al/Si, Au/Si and Au/GaAs structures. Computational fittings of ROYPROF program were used to analyze Doppler broadening results in order to determine kinds of regions that positrons were likely to sample. The interfaces were found acting as a capturing thin layer with negligible positrons stopped in them and their characteristics came only from positrons diffusing to these interfaces, the positron work function of these materials were taken into consideration. In all fittings, the interfaces are found to have 1 nm thickness and act as an absorbing sink for all thermal positrons diffusing towards them, and this indicates either the existence of open volume defects or a weakness of known theoretical models for positron affinities. The result is supported by measurements obtained by applying external electric fields on Al/Si sample. Theoretical fittings have clearly demonstrated the sensitivity of interfaces in these attempts and their importance in data analyzing and in developing of fitting cods.

关键词： Positron Annihilation Interface Metal-Semiconductor Defects

Libyan Licenses Plate Recognition Using Template Matching Method

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Journal of Computer and Communications 2016年第7期4卷 62-71页

作者： Alla A. El. Senoussi Abdella Electrical and Electronic Department University of Benghazi Benghazi Libya

License plate recognition (LPR) applies image processing and character recognition technology to identify vehicles by automatically reading their license plates. The work presented in this paper aims to create a computer vision system capable of taking real-time input image from a static camera and identifying the license plate from extracted image. This problem is examined in two stages: First the license plate region detection and extraction from background and plate segmentation to sub-images, and second the character recognition stage. The method used for the license plate region detection is based on the assumption that the license plate area is a high concentration of smaller details, making it a region of high intensity of edges. The Sobel filter and their vertical and horizontal projections are used to identify the plate region. The result of testing this stage was an accuracy of 67.5%. The final stage of the LPR system is optical character recognition (OCR). The method adopted for this stage is based on template matching using correlation. Testing the performance of OCR resulted in an overall recognition rate of 87.76%.

关键词： License Plate Recognition Optical Character Recognition Computer Vision System

Performance of Regenerative Gas Turbine Power Plant

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Energy and Power Engineering 2017年第2期9卷 136-146页

作者： Hossin Omar Aly Kamel Mohammed Alsanousi Mechanical Engineering Department University of Benghazi Benghazi Libya Faculty of Engineering University of Benghazi Ajdabia Libya

This study aims to investigate the effect of regeneration on the output power and the thermal efficiency of the gas turbine power plant. The effect of ambient air temperature, regeneration effectiveness, and compression ratio on the cycle thermal efficiency was also investigated. An existed gas turbine power plant of AL ZAWIA is used as a base in this study, and the calculations were carried out utilizing MATLAB code. This intensive parametric study was conducted based on the fundamental of thermodynamics and gas turbine relations considering the effect of the operation conditions (ambient air temperature, regeneration effectiveness and compression ratio). It was found that adding regeneration to the simple gas turbine cycle results in an increase in the thermal efficiency of cycle. It was also found that including regeneration in gas turbine cycle results in an increase in the output power of the cycle, and it results in a decrease in the exhaust gas temperature. The effect of the regeneration effectiveness was also predicted. It was found that increasing of regeneration effectiveness results in an increase in the output power of the cycle. It was also found that the cycle thermal efficiency increases with increasing of the regenerative effectiveness. The effect of ambient air temperature was also predicted. Increasing of the ambient air temperature results in a decrease in the thermal efficiency of the cycle.

关键词： Gas Turbine Power Plant Thermal Analysis Regeneration Regeneration Effectiveness

Gravimetric Studies of Ni Electrodeposition with Additives from Deep Eutectic Solvents Using Electrochemical Quartz Crystal Microbalance EQCM

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Open Journal of Physical Chemistry 2020年第2期10卷 87-98页

作者： K. Elttaib A. Benhmid Department of Chemistry Faculty of Science University of Benghazi Benghazi Libya

The gravimetric analysis of electrodeposited nickel is demonstrated using electrochemical quartz crystal microbalance (EQCM) where the nickel coatings come from a solution of the metal chloride salt separately in either a1choline chloride: 2 ethylene glycol (ethaline) or 1 choline chloride: 2 urea (reline) based ionic liquid. The possibility of adapting the Quartz Crystal Microbalance EQCM (which measures the mass attached to the electrode) to probe kinetics of electrochemically-driven solid state phase transformations has been explored in a Ni electrodeposition in absence and presence of complexing agents ethylene diamine en and acetylacetonate acac from both electrolytes ethaline and reline. The study shows that the current efficiency and the rate of deposition of nickel coatings obtained from ethaline and reline baths in absence of brighteners en and acac are different, and the addition of en and acac to both ionic liquid solutions results in a significant decrease current. And the associated growth rate will also be decreased, suggesting that the en acac stops the formation and growth of Ni nuclei. This suggests that the mechanism of growth is changed.

关键词： Electrodeposition Quartz Crystal Microbalance Ethaline Reline Eth-ylene Diamine Acetylacetonate Current Efficiency Ionic Liquids