Digital Repository for University of Tripoli

Integrating photonic microstructures into organic light-emitting diodes (OLEDs) has been a widely used strategy to improve their light out-coupling efficiency. However, there is still a need for optical modelling methods which quantitatively characterise the spatial emission pattern of microstructured OLEDs. In this paper, we demonstrate such rigorous calculation using the reciprocity theorem. The calculation of the emission intensity at each direction in the far field can be simplified into only two simple calculations of an incident plane wave propagating from the far field into a single cell of the periodic structure. The emission from microstructured OLED devices with three different grating periods was calculated as a test of the approach, and the calculated results were in good agreement with experiment. This optical modelling method is a useful calculation tool to investigate and control the spatial emission pattern of microstructured OLEDs. arabic 12 English 89
Adel Diyaf, Emiliano R. Martins, John I.B. Wilson, Graham A. Turnbull, Ifor D.W. Samuel, (7-2015)

Amorphous undoped intrinsic silicon, B-doped silicon and P-doped silicon hybrid bilayer structures with poly(3-hexylthiophene) have been fabricated and their photovoltaic responses have been investigated. Open-circuit voltages and fill factors of the devices are moderate, but strongly dependent on the doping type of a-Si:H films. The highest available open-circuit voltage from the hybrid solar cells within this investigation is 1.23 V in a standard test condition. Both inorganic and organic semiconducting layers contribute to the photocurrent generation. The short-circuit currents appear to be limited by unbalanced charged carriers collected from different sides of the semiconductors, which indicates a way forward in device optimization. arabic 9 English 56
Adel Diyaf, Zhiqun He, John I.B. Wilson, Anna H.N. Lind, Ying Peng, Zhi Zhang(9-2013)

A series of uniform polymer/amorphous silicon hybrid structures have been fabricated by means of solution-casting for polymer and radio frequency excited plasma enhanced chemical vapour deposition for amorphous silicon (a-Si:H). Poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) functioned as a photoactive donor, while the silicon layer acted as an acceptor. It is found that matching the hole mobility of the polymer to the electron mobility of amorphous silicon is critical to improve the photovoltaic performance from hybrid cells. A three-layer p-i-n structure of ITO/PEDOT:PSS(200 nm)/i-Si(450 nm)/n-Si(200 nm)/Al with a power conversion efficiency of 4.78% under a standard test condition was achieved. arabic 11 English 61
Adel Diyaf, Zhiqun He, John I. B. Wilson, Ying Peng(3-2014)

Universities are an essential element for a country’s reconstruction, for its future, the starting point for civil society, a place for discussing and proposing solutions. This consideration has been the base for the initiative Libya Restart. This is the reason why, UNIMED has started the collaboration with Libyan HEIs since 2015 for common participation in projects co-funded in the framework of the Erasmus+ programme. As natural consequence, in 2018 UNIMED decided to launch Libya Restart, an institutional initiative aimed at gaining a deeper understanding of the Libyan Higher Education System, through a research activity performed jointly by UNIMED staff and Libyan University academic and technical staff. Together, we spent more than one year collecting and analyzing data and documentation, discussing results, sharing ideas, making mistakes, finding alternative primary sources. Between 2018 and 2019 we have conducted an assessment work on the Higher Education system in Libya, its main priorities, needs and challenges, through the submission of a quantitative survey and a series of qualitative interviews. In this process, UNIMED has cooperated with the Presidencies and International Relations Offices of 16 Libyan universities arabic 9 English 34
UNIMED(1-2020)

In the present work, the authors have studied conductive surfaces on polyester fabrics by using two types of commercially available conductive polymers; polyaniline and poly (3,4-ethylenedioxythiophene)-poly (styrenesulphonate) (PEDOT: PSS) with 100 nm aluminium thin film evaporated on top of the polymer so the fabric becomes a conductive substrate for inorganic thin film solar cells. Conductive polymer surfaces on woven polyester fabrics were obtained by knife-over-table coating technique. Surface resistivities for polyaniline and PEDOT: PSS coated fabrics were measured and found in the range of 400 × 103 and 1 × 103 Ω/□, respectively. Thermal stability tests were carried out to evaluate the effect of specific periods of heal treatment at different elevated temperatures on resistance of polymer coated conducting textiles. PEDOT: PSS exhibited better stability than panipol. According to long term tests, PEDOT: PSS coated samples showed improvement in conductivity over 3 days whereas panipol showed the opposite. Transmission Line Model tests were performed to measure aluminium/polymer contact resistances which were found to be 120 × 103 Ω for polyaniline and about 46.3 Ω for PEDOT: PSS. Mechanical bending tests for aluminium/PEDOT: PSS/fabric samples showed that the polymer can maintain the conductivity of samples by bridging micro-cracks in the metal film. arabic 10 English 59
Adel G A Diyaf, John Wilson, Robert R. Mather(1-2014)

Toutes les ressources historico-sociolinguistique offrent un riche descriptif de l'héritage linguistique en Libye à travers de nombreux facteurs : historique, archéologique, économique, social. Mais, sur le plan de la linguistique, peu d'études se sont penchées sur la Libye. Dans la présente étude, nous essayerons d'étudier à travers de facteurs historicosociolinguistique les langues d'hier et aujourd'hui. arabic 18 English 84
FATHI SALEM ALI TERFAS(1-2020)

Many soil regulating ecosystem services (ES) are linked to Earth’s atmosphere, but associated monetary values often are unknown or difficult to quantify. Atmospheric deposition of calcium (Ca2+) and magnesium (Mg2+) are abiotic flows (wet, dry, and total) from the atmosphere to land surfaces, which potentially can become available to sequester carbon (C) as soil inorganic carbon (SIC). However, these processes typically have not been included in economic valuations of ecosystem services. The primary objective of this study was to demonstrate an approach for valuing non-constrained potential SIC sequestration from atmospheric Ca2+ and Mg2+ deposition based on the concept of the avoided social cost of carbon dioxide emissions (SC-CO2). Maximum monetary values associated with the non-constrained potential SIC sequestration were compiled for the contiguous United States (U.S.) by soil order, land resource region (LRR), state, and region using available deposition data from the National Atmospheric Deposition Program (NRSP-3). For the entire contiguous U.S., an average annual monetary value for the non-constrained potential SIC sequestration due to atmospheric Ca2+ and Mg2+ deposition was $135M (i.e., $135 million U.S. dollars, where M = million = 106). Mollisols, Alfisols, and Entisols were soil orders with the highest average annual monetary values for non-constrained potential SIC sequestration. When normalized by land area, however, Vertisols had the highest average annual monetary values followed by Alfisols and Mollisols for non-constrained potential SIC sequestration. From a more agricultural perspective, the LRRs with the highest average annual monetary values for non-constrained potential SIC sequestration were the Western Range and Irrigated Region (D), the Central Feed Grains and Livestock Region (M), and the Central Great Plains Winter Wheat and Range Region (H). When normalized by area, the LRRS with the highest average annual monetary values were the Southwest Plateaus and Plains Range and Cotton Region (I) and the Florida Subtropical Fruit, Truck Crop and Range Region (U). Among the U.S. states, the highest average annual monetary values for non-constrained potential SIC sequestration were Texas, Kansas, and New Mexico, but when normalized by area the highest values by state were Kansas, Iowa, and Texas. Geographical regions in the contiguous U.S. with the highest average annual monetary values for non-constrained potential SIC sequestration were the South Central, Midwest, and West; when normalized by area, the highest values by region were South Central, Midwest, and Northern Plains. Constraints on maximum monetary values, based on physical, chemical, biological, economic, social, and political limitations, need to be considered and quantified to obtain more precise and accurate accounting of the ES associated with SIC sequestration due to atmospheric Ca2+ and Mg2+ deposition. arabic 14 English 112
Elena A. Mikhailova, Hamdi A. Zurqani, Christopher J. Post, Mark A. Schlautman(5-2020)

Annona muricata (Graviola) has many medicinal properties and used widely in traditional medicine for treatment various disorders. The present study was conducted to evaluate phytochemical and quality control (QC) of random sample of graviola dietary supplement capsules (DS) which sold in the Libyan market as anticancer product. As well as the present work designed to evaluate heatoprotective effects of aqueous extract of graviola fruit pulp or aqueous DS of graviola capsules against trichloroacetic acid (TCA) induced hepatotoxicity in albino mice. Quality control parameters were determined on random samples of graviola DS using standard methods. A total of 120 female mice were divided into 6 groups and were used for biological screening to determine biochemical and histopathological alteration in liver of mice treated with TCA with or without aqueous extract of A.muricata fruit pulp or DS of graviola. The results of quality control and phytochemical screening revealed that all quality control tests conducted on the random sample of DS capsules of graviola were within normal values according to the standards of the Quality Control Center for Pharmaceuticals in Tripoli, only few samples showed slight increase in the moisture content. However, all samples appeared free from microbial contamination. While, growth of fungal contamination (Pencillium Spp) in the same samples were detected but all samples appeared free from aflatoxins contamination. Also, all samples were free from industrial radioactive contamination. Phytochemical study revealed presence of alkaloids, tannins, steroids, glycosides, falvonoids, anthraquinones, saponin and coumarins in extracts of graviola fruit pulp and graviola DS capsules. However, absence some phytochemical components in DS capsules was detected. The result of biological screening revealed that no clinical signs and abnormalities in behavior and external feature in mice treated with aqueous extract of graviola fruit pulp or aqueous extract of graviola DS capsules. However, the treatment with aqueous extract of graviola fruit pulp and DS of graviola reduced the abnormal changes in behavior and external features in female mice intoxicated with TCA, markedly reduced the mortality in TCA administrated mice and induced slight improvement in the final body weight comparing to TCA only intoxicated group. Biochemical study revealed that administration of aqueous extract of graviola fruit pulp or aqueous extract of DS of graviola significantly decreased the elevated serum activities of AST and ALT compared to TCA only intoxicated mice. Histological examination revealed that administration of aqueous extract of graviola fruit plup or aqueous extract of DS of graviola with TCA induced ameliorative changes and disappearance of the most pathological changes in the liver tissue compared to of TCA only intoxicated mice and the ameliorating changes were more obvious in the mice treated with aqueous extracts of DS of graviola and TCA. The present results demonstrate that A. muricata play an important role in the protection against TCA induced hepatotoxicity. It can be concluded that the present study provide some pharmacological and therapeutical informations about extract of the graviola fruit pulp and DS of graviola capsules which can use in future investigations and applications and demonstrated presence of important phyochemical constituents in the graviola fruit pulp extract and DS of graviola capsules. The extract of the graviola fruit pulp and DS of graviola capsules have protective effects against TCA induced liver toxicity in mice. arabic 33 English 168
Ajlal A. A. Alzergy, Mukhtar R. Haman, Muftah A. M. Shushni, , Fairouz A. Almagtouf (2-2018)