Libya Journal of Applied Sciences and Technology
The Libya Journal of Applied Sciences and Technology (LJAST) is a peer-reviewed, open-access scientific journal published by the College of Engineering Technology – Janzour, Libya. The journal is dedicated to publishing high-quality original research, review articles, and applied studies in the fields of engineering, applied sciences, technology, and interdisciplinary research. LJAST aims to provide an academic and professional platform for researchers, academics, engineers, industry professionals, and decision-makers to exchange knowledge, share innovative ideas, and present practical solutions to contemporary scientific and technological challenges. The journal particularly encourages applied and industry-oriented research that contributes to technological advancement, sustainable development, innovation, and the integration of scientific research with real-world applications at both regional and international levels. As an open-access journal, LJAST ensures that all published articles are freely accessible to researchers and readers worldwide, supporting the broad dissemination of scientific knowledge and promoting global academic collaboration. The journal follows a rigorous peer-review process and is committed to maintaining high standards of academic integrity, research quality, ethical publishing practices, and scientific excellence.
College of Engineering Technology – Janzour,
Calculation of the Concentration Ratio and Solar Flux Distribution of the Truncated Pyramid Solar Concentrator Using Three-Dimensional Ray Tracing Simulation
The Truncated Pyramidal Solar Concentrator (TPSC) is a four-mirror device configured as a square frustum, utilized in solar oven technology for medium-temperature applications. This study aims to calculate the concentration ratio and solar flux distribution on the receiver by ray-tracing incident solar radiation from the aperture until it strikes the receiver or escapes. Assumptions include solar rays as equal, symmetric straight lines tilted by the altitude angle and the solar azimuth angle, and flat, smooth mirrors with negligible absorption. This study investigates the impact of mirror height, receiver-to-aperture area ratio, and solar ray incidence angles, on flux distribution and concentration. Results indicate that flux distribution is significantly affected by height, receiver-to-aperture area ratio. At (β=φ=0), the concentration ratio increases with both height and aperture area, although the latter only up to a limit. At (β=10) and (φ=0), the concentration ratio increases with height but decreases with increasing aperture area. Comparing the two cases, the concentration ratio is found to decrease with increasing altitude angle, suggesting that the TPSC is best utilized for a short period. The solar azimuth angle also reduces concentration, but less significantly than altitude angle. We conclude that height and aperture area have a major impact on flux distribution and concentration. This mathematical model is crucial as a design tool, providing a more accurate and detailed computational framework for flux mapping on the receiver compared to previous studies, thereby enabling thermal performance optimization in solar applications.
Simulation and Performance Analysis of Photovoltaic Units under the Influence of Environmental Variables using MATLAB/Simulink
Solar energy is one of the most important renewable energy sources, effectively contributing to meeting the growing global demand for electricity while reducing carbon emissions. Despite the high performance of these units, a precise quantitative analysis of the impact of varying environmental factors on them using dynamic modeling remains essential to improve their performance in field conditions, particularly solar irradiance intensity and temperature, which directly affect the electrical conversion efficiency of the system. This study aims to model and simulate the electrical performance of a high-efficiency photovoltaic unit of type SunPower SPR-415E-WHT-D using the MATLAB/Simulink environment, in order to analyze the influence of environmental variations on current-voltage (I-V) and power-voltage (P-V) characteristics. The simulation was carried out over an irradiance range of 200–1000 W/m² and temperatures ranging from 15–35°C. The results showed that increasing irradiance leads to a significant rise in maximum power, increasing from 18.7 W at 200 W/m² to 424.8 W at 1000 W/m², representing a growth rate of approximately 2171%. In contrast, rising temperature causes a decrease in voltage and consequently power, with maximum power decreasing by 5.27% when the temperature increased from 15°C to 35°C. These results clearly highlight the urgent need for thermal management and the implementation of effective performance-enhancing strategies, including the integration of Maximum Power Point Tracking (MPPT) algorithms in photovoltaic systems, particularly in regions with hot climates and high solar irradiance levels.
Comparison of Petroleum Hydrocarbon Levels in Western Libyan Beach by Gravimetric and Spectroscopy Analysis
Fourteen shore water samples (denoted as w) from west of Tripoli shoreline, were examined for their petroleum hydrocarbon contents by gravimetric and spectroscopy analysis. Known amounts of beach water (w) were extracted with a suitable volume of chloroform (CHCl₃). The extracts were measured spectrophotometrically through calibration curves of absorptions at 410nm and 260nm to determine the concentration of petroleum hydrocarbons. Infrared analysis was also conducted on hydrocarbons extracted from shore water samples to assess the degree of oxidation occurred to the extracted hydrocarbons. This was obtained by comparing the relative absorption values at 1736 and 1712cm⁻¹ , normalized with respect to 2925 cm⁻¹; C-H stretching vibration; to rule out effects due to concentration. Gravimetrically, hydrocarbon concentrations in shore water (w) ranged from 0.05 to 9.50 ppm, while spectrophotometrically concentrations at 260nm and 410nm ranged from 0.470 to 2.74ppm, depending on location and industrial activities. The variation between the hydrocarbon concentrations by gravimetric method and the spectrophotometric method was due to the fact that gravimetric method measures total organics, but the spectrophotometric method focused on hydrocarbons which is a subset of organics. The Infra-red analysis showed densities at 1736cm⁻¹ (Acid-I) and 1712cm⁻¹ (Acid-II) which normalized with respect to the absorbance at 2925cm⁻¹ (Alkyl C-H) being equal to 1.00, the results were ranged 0.044 to 0.128 as acid-I and ranged 0.027 to 0.088 as acid-II, depending on effects of Prevailing Conditions.
Potential Opportunities for Libya's Construction Industry After Political and Economic Instability: A Comparative Analysis
This study examines the challenges and opportunities for Libya's construction industry following years of political and economic instability. Through a mixed-methods approach combining statistical analysis of survey data (n = 150 professionals), comparative case studies (Iraq, Rwanda), and literature review, the research identifies political instability as the most significant barrier (β = 0.42, p < 0.001), correlating strongly with project delays (r = 0.82) and cost overruns (r = 0.84). The analysis reveals Libya's critical gaps in regulatory frameworks, funding mechanisms, and technology adoption (12% BIM implementation vs. 24-41% in comparator countries). Key findings highlight that: (1) sectoral recovery requires parallel progress in political stabilization, (2) financial innovations like reconstruction funds are urgently needed, and (3) strategic technology transfer could accelerate rebuilding. The study proposes a phased roadmap for stakeholders—policymakers, firms, and international partners—emphasizing stability-first measures, PPP models, and capacity building. By adapting lessons from successful post-conflict recoveries, Libya can transform its construction sector into a driver of sustainable development. This research contributes actionable insights for reconstruction planning in fragile states.
Micro T- mixer: The effect of scaling factor and mixing angel
Different phenomena observed in various experiments indicate that the flowing mechanisms of liquids in microchannels are still not understood clearly. Computational fluid dynamics (CFD) simulation was used to simulate liquid flow in a T-shaped micromixer whose structural dimensions and operating conditions were varying. The results show that, the formation of vortices in the mixing zone arises through the influence of a T-junction (changes flow direction and gives rise to a secondary flow). After the mixing zone, the flow is almost fully developed and mixing occurs by a molecular diffusion mechanism only. The results also show that the mixing angle had a significant effect on the T-mixer performance. This can be attributed to the fact that for the engulfment flow regime, there is an optimum T-angle at which the effect of sharp bend reaches a strength value. If liquids enter into inlets with the same velocities, the flow was symmetrical; otherwise, the symmetry was broken up. The asymmetrical inlet velocities help to promote mixing quality. To illustrate the differences of liquids flow between macro- and micro-scale, the mixer is scaled in proportion, and the simulation shows that the smaller the mixer, the better the mixing quality.
Thermal Performance Assessment of Heat Exchangers In An Industrial Ethylene Production Facility
This study provides a comprehensive performance assessment of three critical heat exchanger units (2-H-301, 3-H-601, and 3-H-501) within an industrial Ethylene production facility in Ras Lanuf plant. Steady-state monitoring and direct data acquisition from operational equipment were conducted with subsequent data analysis performed using energy balance equations to quantify key thermal performance parameters. These parameters included overall heat transfer coefficients, heat duties, hot and cold fluid temperature and pressure ranges, capacity ratios, and effectiveness of each exchanger. Results reveal that the 2-H-2301 unit exhibits an overall heat transfer coefficient over 50% below the design specification and a heat duty exceeding 80% of the intended design. In the 3-H-901 unit, both heat duty and overall heat transfer coefficient were observed to fall over 75% below design standards, likely due to fouling, which adversely impacted effectiveness, capacity ratio, and the temperature profile of hot and cold streams. Conversely, performance of the 3-E-401 exchanger was within acceptable limits, with the heat duty, hot-side temperature differential, and capacity ratio aligning closely with design expectations. These findings offer a rigorous qualitative performance evaluation of the heat exchangers, highlighting areas requiring operational optimization to maintain design efficiency within industrial polyethylene processes.
Residue Upgrading Options for Maximum Gasoline Production From Libyan Crude Oil
Different refinery configurations are investigated for upgrading projects to increase gasoline production for local market demand. Libya is an important contributor to the global supply of light and sweet crude. It has five domestic refineries, all of which are simple hydro-skimming units. This work presents a theoretical approach for upgrading of atmospheric and vacuum residue derived from the heaviest Libyan crude oil. Obtained results show that option 3, which included delayed coking, has shown the optimum in terms of maximum gasoline.
Using Bernoulli's Differential Equation To Solve Thermodynamic And Aerodynamic Problems Describing Changes In Velocity Or Pressure
Bernoulli's equation represents a cornerstone in fluid dynamics, describing the interdependence of pressure, velocity, and elevation along a streamline. Rooted in the principle of energy conservation, it offers essential insights into the behavior of thermodynamic and aerodynamic systems. This study investigates the application of Bernoulli's differential form to analyze variations in velocity and pressure within fluid flows. The derivation, underlying assumptions, and practical implications of the equation are discussed in detail, with emphasis on its use in aerodynamic analyses (e.g., lift and drag estimation) and thermodynamic applications (e.g., flow behavior in nozzles and diffusers). Through selected case studies and computational simulations, the utility of Bernoulli's equation in engineering design and system analysis is demonstrated. Furthermore, the study addresses the equation's limitations, particularly in scenarios involving compressible and viscous flows, and outlines relevant extensions to enhance its applicability under such conditions.
Evaluation of Effect Heat Treatment on Mechanical Properties of Low Carbon Steel with Different Cooling
In this study, Low carbon steel C 17 were selected to investigate the effect of different cooling during the heat treatment on mechanical properties. The samples were heated in a heat treatment furnace at approximately 980°C for almost 1 hour and then cooled by different quenching media (water, air, oil). The results show that Oil quenching also had a slight effect on the metal tensile strength and hardness. The change in the ultimate stress was observed. Upon water quenching, the result was 745 N/mm², while the ultimate stress of the sample before heat treatment was 431 N/mm². Meanwhile, hardness after water quenching. The hardness before treatment was 126 HB, and after treatment and water quenching, it was 263 HB. The impact test did not fracture despite the increased hardness because the metal still retained a high degree of ductility.
Mechanical Vibration Analysis of Ship Hulls Using Numerical Simulation
This study investigates mechanical vibrations in ship structures using advanced numerical simulation techniques. A three-dimensional model of a tugboat hull was developed using CAD software, followed by finite element analysis (FEA) in Abaqus to evaluate stress distribution and dynamic response. Computational fluid dynamics (CFD) was integrated to simulate water flow around the hull and quantify the resulting hydrodynamic forces. The numerical model was validated through comparison with field data collected from Tripoli Seaport. Ultimately, this study seeks to provide a comprehensive scientific framework for vibration analysis in ships, contributing to improved structural design, reduced vibrational impacts, and enhanced environmental sustainability in marine engineering applications.
Improvement of Surface Quality by Reducing the Part's Surface Roughness Texture
Polyamide (PA) materials are extensively used in Selective Laser Sintering (SLS) for producing functional components. Among them, DuraForm PA and DuraForm GF from 3D Systems, along with PA 2200 and PA 3200 GF from EOS, are widely adopted for their favourable mechanical and thermal properties. Glass-filled (GF) composites, composed of a polymer matrix reinforced with glass particles, provide enhanced stiffness and dimensional stability compared to unfilled PA materials. This study focuses on improving the surface quality of laser-sintered (LS) parts and mitigating the rough surface texture characteristic of the SLS process. Experiments were conducted using a 2500 HiQ 3D System, employing a fractional factorial design of experiments (DOE) with five factors at two levels. The melt flow rate (MFR) was used as an indicator of recycled powder quality, with PA 2200 powder exhibiting an MFR range of 15–20. Results reveal that surface texture is strongly affected by scan spacing and interactions among laser power, scan speed, and scanning strategy. The proposed approach offers a systematic framework for optimizing LS process parameters for recycled PA 2200 powder, enhancing surface finish and overall part quality.
Risk Management in Libyan Construction Projects During Times of Political Unrest
This study aims to examine risk management in Libyan construction projects during periods of political unrest, measuring the frequency and severity of political, security, economic, and logistical risks, identifying effective mitigation strategies, and assessing stakeholder perceptions. Using a mixed — methods approach—including surveys of 150 construction firms, interviews with key stakeholders, and statistical analysis—the research evaluates how political instability disrupts project timelines, budgets, and safety . Findings reveal that 82 % of projects face political unrest — related delays (averaging 7 .2 months), while currency fluctuations contribute to the highest cost overruns (35%). Militia interference affects 68 % of projects, increasing costs by 15 %. Effective mitigation strategies include dollar — denominated contracts (reducing overruns by 9 %), tribal negotiations (83 % success rate), and modular construction(30–50 % delay reduction ). Stakeholder priorities diverge, with investors favoring external guarantees (e .g., World Bank insurance ) and governments advocating local solutions . The study recommends that firms adopt hybrid contracts, preposition materials, and engage local Communities, while Libyan authorities should streamline permitting, strengthen judicial enforcement of contracts, and implement anti — corruption measures like block-chain tendering. International partners can support political risk insurance and modular construction training. The findings underscore the need for adaptive, context — specific risk management in conflict zones, combining immediate operational adjustments with long — term institutional reforms to enhance project resilience
Computer Simulation of the Performance of An Open Solar Assisted Desiccant Cooling System
The performance characteristics of an open-cycle solar assisted desiccant cooling system were evaluated using computer simulation. A computer program was built and developed to simulate the effect of various design and operating conditions on the performance of the individual components making up the simulated system. They include a V-corrugated plate type solar air heater, a rotary silica gel desiccant dehumidifier, a sensible cooler and an evaporative cooler. The overall system performance was evaluated in terms of several parameters including the supply air temperature, the sensible cooling capacity and the coefficient of performance of the system. The effect of operating parameters such as the outdoor air temperature, outdoor moisture content, regeneration temperature, dehumidifier efficiencies, sensible cooler effectiveness and evaporative cooler effectiveness was incorporated in the analysis. Actual hourly weather data for Benghazi on selected clear summer days were used to assess the system performance during the day. The simulation was accomplished with a direct supply of hot air, from the solar air heater, for regenerating the dehumidifier bed. The performance of the solar air heater and the desiccant dehumidifier was first simulated independently to assess their compatibility when used in the system. Simulation results of the overall system performance showed that the heat exchanger effectiveness, evaporative cooler effectiveness and ambient conditions have the major influence on the system performance. Whereas, the influence of dehumidifier performance and regeneration temperature on the system performance was less pronounced. It was found that the simulated system can generate a cool supply of air at acceptable comfort conditions for most hours of typical clear summer days under the local weather conditions of Benghazi. The supply air temperature obtained from the system was found to be nearly constant during the selected days and at an average value for Benghazi of 18°C.
Simulation of a V-Corrugated Solar Air Heater
The performance characteristics of a V-corrugated plate type solar air heater was investigated analytically using computer simulation. A Visual Basic computer program was built to predict the hourly instantaneous collection efficiency, useful energy gained and the outlet air temperature of the solar air heater. The effects of various design and operating conditions, such as mass flux, wind speed, absorber plate emissivity, and collector tilt angle and inlet air temperature, on the predicted values were examined. Results of the simulation of the solar air heater indicated that increasing mass flux of the air through the collector increases the instantaneous efficiency and the useful energy gained but reduces the air outlet temperature rapidly. An air outlet temperature of about 69°C was obtained in winter at midday at a mass flux of 0.1kg/s.m2 with an average collection efficiency of 34%. Also, it was found that absorber plate emissivity, and (inlet-ambient) temperature difference affect the solar air heater performance in varying degrees. An optimum tilt angle in Jalu for the solar air heater during the period from May to August and from November To February was found to be equal to 5°, 50 from the horizon, respectively. Also, changing the tilt angle by ±10° around its optimum value reduces the useful energy gained by only 2% during the same period in summer and winter. Experimental data of previous work were compared with the simulation results and found in very good agreement.
Study of the effects of heat treatment on reinforcing bars Which is produced by the Libyan Iron and Steel Company
This research paper aims to study the effects of heat treatment on 14 mm reinforcing bars that are produced by the Libyan Iron and Steel Company. These operations were conducted in the quality control laboratory, and it was found that there are two types of 14 mm reinforcing bars: (G-40) and (G- 60). The difference between them is the percentage of carbon present in their chemical composition, as the percentage of carbon in the variety (G-40) ranges between 0.25% and 0.38%, and as for the variety (G-60), it ranges between 0.35% and 0.45%[1]. In this research paper, three different heat treatment processes were carried out: hardening, neutralization and fermentation at a constant temperature of 850°C and for a constant period of 30 minutes on 14 mm reinforcement bars with American specifications (ASTM A615 G-40 and G-60)[5]. After performing these operations, a change occurred in the internal structure of the material and its phases, which led to a change in the mechanical properties of these bars. To know and determine this change, mechanical tests (tensile test and hardness test) and microscopic examination were performed.
Study of cold storage design and the impact of basic variables on its effectiveness
In this paper, we study the different types of cooling and freezing stores that can actually be used to store and preserve foodstuffs, as well as the types of heat-insulating materials and moisture-insulating materials that are used in the structural composition of these stores, in addition to the method of calculating the various items that constitute the thermal load of these stores. For the purpose of evaluating and calculating the thermal loads of cold stores in big Market for storing table eggs and foodstuffs. In this research paper, the first and second warehouses were chosen for these stores. To complete these calculations, the design conditions (temperature) for the air outside the stores were determined based on the temperatures that were recorded for a period of 6 days from (11 am to 5 pm) and the temperatures that were taken from the meteorological station, the design conditions inside the warehouse were determined depending on the quality and grades of the stored food items Suitable storage temperature. Design calculations have been performed and practical readings have been recorded, and through the study it is clear that the capacity of the evaporators is much greater than the capacity of the stored materials.
Development of a Combined (Parallel & Parabolic) Rheomatic Device for Determination of Pressure Dependent Viscosity
Hydrodynamic pressure technique is a relatively new and innovative technique for rheological studies of viscous Newtonian fluids. These principles extensively used for the last twenty years for drawing and coating of strips and wires. The Rheometric Device consists of a rotating inner cylinder (rod) in a fixed hollow outer cylinder. The complex geometry gap between the two cylinders filled with a viscous non-Newtonian fluid. When the rod rotates inside, while the hollow cylinder filled with a viscous fluid, shearing takes place and hydrodynamic pressure develops, the magnitude of which is dependent on the shape of the surfaces, the viscosity of the fluid as well as the shear rate, the speed with which the inner solid rod is rotating. The Rheometer has been developed to determine the Rheological properties of fluid at pressures of up to 100 bar and a shear rate range of 500 to 400 sec⁻¹. Theoretical model developed based on Newtonian characteristics, shear rate viscosity relationship was determined using the Rheometer (combined parallel and parabolic unit) at different pressures by comparing the calculated theoretical pressure distribution with the experimental results
Evaluation of Gamma Ray-Induced Ultrasound Changes in Human Cells AFM and SEM Techniques at Low-Dose Exposure
Exposure to high-dose ionizing radiation is known as a human carcinogen factor, but our information about the effects of low-dose ionizing radiation such as occupational exposures is limited. The main concern of scientific community is biological consequences due to low-dose radiations. This study aims to evaluate the effects of low-dose gamma radiation on expression changes of apoptotic genes(bax and bcl-2) in the rat peripheral blood lymphocytes.In this experimental study, 42 adult male rats were classified into 6 groups, which was exposed to various doses values ranged from 20mGy to 1000mGy by y-rays from a Co-60 source. Blood samples were provided for analysis of gene expression 24 h after gamma radiation by relative quantitative Reverse Transcription - Polymerase Chain Reaction (RT- PCR). Radiation sensitivity of rat lymphocytes was measured by the bax/bcl-2 ratio as a predictive marker for radio-sensitivity.
Evaluation the Performance of Empirical Correlations for Predicting the Dead Oil Viscosity and Isothermal oil compressibility for Libyan Crude Samples
Understanding the PVT parameters is essential for various petroleum calculations, including the assessment of hydrocarbon flow characteristics, forecasting future performance, designing production facilities, and strategizing enhanced oil recovery methods. Ideally, the PVT properties of hydrocarbons are derived from laboratory analyses conducted on either bottom-hole samples or recombined surface samples. However, laboratory data may not always be accessible due to economic or technical constraints. In such instances, empirical correlations are employed to estimate these properties. These correlations have been formulated based on fluid samples from specific geographical regions. Given the diverse compositions of crude oils across different areas, relying on empirical correlations to predict PVT properties may yield unsatisfactory results when applied to hydrocarbons that behave differently from the fluid samples used to develop the correlations. This study assesses various PVT correlations to estimate the viscosity of dead oil (μod) for Libyan crude oils, utilizing 58 data points, and examines isothermal compressibility (Co) for Libyan crudes with 145 data points across approximately 100 distinct reservoirs. The evaluation criteria employed in this research include statistical and graphical error analysis. Existing correlations were applied to the Libyan dataset, and error analysis was conducted by comparing the predicted values with the original experimental values. The most accurate correlation for each PVT parameter has been identified. The findings indicate that the correlation proposed by Kartoatmodjo & Schmidt yields a dead oil viscosity with an Average Absolute Error Ratio (AAER) of 18.53% and a relative coefficient of R² = 0.1512. For isothermal oil compressibility, the correlation by Ahmed (1985) demonstrates the best performance, with an AAER of 31.67% and a relative coefficient of R² = 0.104%.
Lean Six Sigma, supply chain, analysis, Measure, DMAIC, control
The study sought to explore the impact of the approved approach of application of Lean and Six Sigma, which focuses on improving quality and reducing lead-time, and removing waste in the supply chain. As this integration of both applications is suitable for small and medium-sized companies (SMEs), the manager of company X wishes to solve its problems in lead time and transportation costs. The paper used the application of Lean and Six Sigma within the DMAIC stages.(define, measure, analyse, improve, control) The study also aims to take advantage of the stages through careful application of them to achieve the best results of reducing lead time and removing waste.
Resampling adjusted likelihood and average estimate approaches for microarray data analysis
The burgeoning field of genomics has reinvigorated interest in multiple-testing methods as it introduces new methodological and computational challenges. Whole genome microarray studies (e.g., differential expression, differential methylation, ChIP-chip) offer the possibility to test millions of traits in one genome. This article discusses the preterment of Adjusted likelihood approach and Average estimate approach (see Ewhida, Alammari and Ihwil, 2022; Jiang and Doerge, 2008) for estimating the proportion of true nulls π0 for CHIP-on-chip experiment data. Which has been done by Elnfati, Iles and Miller 2016, to express where the protein and DNA are bound, and the sample was taken from Drosophila fly (Fruit flies) in three replicates to determine the effect of HISTONE protein on fetus growth. The study demonstrates that, the Adjusted likelihood approach estimator performs very well.
Estimation of Original Oil in Place & Aquifer Characterization of Ghani Field – Farrud Reservoir
The material balance MB method is a powerful technique used to study reservoir performance and describing the important properties of the reservoir, including the estimates of original oil in place, and the strength of aquifer. It also provides the understanding of drive mechanisms at work, such as solution gas, water influx, and gas cap. This study aims to determine the original oil in place of the Farrud reservoir using both Volumetric & Material Balance methods using MBAL Software. Also, diagnostic the aquifer influx presents into the reservoir and their strength. Two scenarios involved in this study; the first scenario is building a reservoir model without aquifer connecting. The second scenario, three aquifer models were selected to achieve the matching between observed reservoir and simulation data. The Original Oil in Place Ghani-Farrud reservoir estimated by volumetric method was 735.24 MMSTB and the material balance used by Campbell Method was 920.8 MMSTB, the different between two values was about 21.8 %; that due to the uncertainty and lack of the data collected at the early lifetime, as well as the heterogeneities in the average reservoir parameter calculations. MBAL software led to the best analytical Matching between measured reservoir and simulation pressure which is improved by Hurst-van Everdingen Modified model with minimum standard deviation of 0.635. Based on the diagnostic plot of the Campbell, the a moderate strength aquifer is associated with the Farrud reservoir model. The Hurst-van Everdingen Modified model described the aquifer properties.
Developing an academic institution system based on the Google cloud platform
The Libyan Academy (LA) Administration always aims to develop an integrated system that provides and manages various services for the Libyan Academy, such as student management, educational materials management, human resource management, and other systems. Suggested approach Student Information System (SIS) aims to digitise student system processes by developing a Student Information System (SIS) based on Google Cloud Platform (GCP). A set of components are integrated such as Google Cloud SQL (GCS) and G-suite to orchestrate the SIS processes to handle requests firmly. That will leverage the system performance efficiently, downgrade the cost expenses and reduce the development to market time, through owning a usable system with greater scalability.
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An Estimation of the Optimal Time of Maintenance Interval in the Aircraft Systems Using Fault Tree Analysis
Aircrafts maintenance is a major and complex activity with aiming to achieve high standards of safety and attain an increased level of reliability of system at the lowest possible cost. therefore, estimation of failures risk of aircrafts has become necessary. The paper aimed for estimating failures risk in order to determine an optimal time for starting in the maintenance activities using Fault Tree Analysis (FTA) approach. The FTA approach uses scenarios to identify a critical equipment that can effect on the operating performance the aircrafts. Based on the estimated risk scenarios that extracted through maintenance records of aircrafts, the results showed that FTA approach has able to estimate the failures risk for any critical equipment run under different environmental conditions.
Adjusted likelihood approach to estimate the proportion of true null hypotheses in multiple tests
A number of methods have been established to estimate the proportion true null hypotheses in multiple testing under the assumption of independency. On other hand, the test statistics are either discrete or continuous. In this paper, we will review an existing likelihood approach for estimating the proportion of true nulls controlling the false discovery rates when the test statistics are continuous (see Hualing and Hanfeng, 2021). We therefore present an extension of these method that can successfully make some improvement of the performance. Simulation study demonstrates that the new estimator performs very well.
Obstacles to scientific research from the perspective of researchers
The study aims to identify the problems and obstacles facing researchers in research centers affiliated with the Libyan Authority for Scientific Research, as it is the only Libyan institution concerned with researchers, through submitting research proposals and then implementing them, as well as when publishing in scientific journals and periodicals classified in local and international databases if possible. It also aims to reveal statistically significant differences between the mean responses of researchers on the publication questionnaire. The study used the descriptive approach, and employed the questionnaire as a tool, on a sample of researchers in research centers (numbering 55 researchers). The study included four axes: the first axis addressed (obstacles related to the workplace), the second axis addressed (obstacles related to equipment and devices), the third axis addressed (obstacles related to the publishing entity), while the fourth and final axis addressed (the goals and motivations of researchers for their scientific production).
Exploiting pear leaves in biosynthesis of silver nanoparticles
Biosynthesis techniques have a number of advantages over other methods for producing silver nanoparticles (AgNPs), which provide a wide range of applications. The present work highlights the biosynthesis of AgNPs by mixing pear leaf aqueous extract with silver nitrate, and the formation of AgNPs was observed by the change of mixture color from yellow to dark brown and visible spectrophotometry. Moreover, the effect of pH, reaction time, AgNO3 concentration, extract volume and temperature on the suggested approach was also studied. The results showed that pear leaf aqueous extract is an excellent material for the biosynthesis of AgNPs, and by controlling the mentioned parameters that influence synthesis, a large number of AgNPs with small sizes may be produced.
Weak Forms of Open and Closed Functions by Using b-δ Open Set
The notion of β-open set and δδ-open set were introduced by many topologists and several research papers with interesting results in different respects came to existence. Also, the notion of b−δ-open set was introduced by Almalty (2011). The aim of this work is focused on generalization of functions in topological space and new classes of functions called weakly b−δ-open function and weakly b−δ-closed functions via b−δ-open set. The connections between these functions and other related functions are investigated. Moreover, we introduce some theorems and propositions that are related with these functions. The result of this study shows how we can define new notations of functions by using a weak form of b−δ-open set.
The Impact of Internal Marketing Dimensions on the Teaching and Research Performance of Faculty Members in Technical Colleges in Tripoli
Based on these results, the study recommended adopting a comprehensive internal marketing strategy to address existing weaknesses and enhance integration among its dimensions. Furthermore, it emphasized the importance of improving the overall performance of faculty members by achieving a more balanced approach between teaching responsibilities and scientific research activities. From a theoretical perspective, these findings reinforce the principles of internal marketing theory, which posits that fostering internal communication, empowerment, and supportive leadership enhances employees’ commitment and performance. The moderate and low levels observed in motivation and training suggest a gap between theoretical expectations and practical implementation within the studied institutions. Consequently, strengthening these dimensions could lead to more sustainable improvements in academic performance and institutional effectiveness.
Evaluating the Performance of Commercial Banks Using the CAMELS Model – An Applied Study on Bahraini Banks
This study aims to identify the "CAMELS" model as an effective and accurate tool to be used as a performance evaluator in banking industries and to anticipate future and relative risks. Banks being exposed to financial faltering is considered one of the important events that draws attention and calls for study, due to its extremely dangerous effects. CAMELS ratios are calculated in order to focus on financial performance, which stands for Capital adequacy, Asset quality, Management, Earning, Liquidity, and Sensitivity. In this study, some important ratios were selected and calculated to assess the performance of banks, and the data used were obtained from the annual financial reports of Bahraini banks. The obtained data are then compared with standard or model bank ratios. Certainly, the trends in accounts and related figures show important points for managers, as well as the CAMELS model rating can be an efficient tool to manage, control, and make sound decisions.