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,
Using ARIMA model to forecast the Reported Crimes in Libya from 2020 to 2025
A time series is a collection of data that was compiled chronologically. Most time series can be predicted based on their present and historical values. Software programs like SPSS and Minitab are made specifically to process time series data. The SPSS and Minitab software programs can be used to create the autoregressive integrated moving average (ARIMA) model, a time series forecast technique. In this paper, the forecasting process using the ARIMA model is illustrated using the SPSS and Minitab software. For instance, the predicted period for reported crimes (RC) in Libya is from 2020 to 2026.
Copyright (c) 2022 https://creativecommons.org/licenses/by-nc/4.0
Hydro-Power Energy Recovery in Water Pipelines Networks, A Case Study of Man-Made River in Libya
The Man-Made River (MMR) in Libya is one of the world’s largest water transfer systems, yet it consumes vast amounts of electricity to deliver water across long distances. This research addresses the challenge of energy demand by exploring the recovery of hydraulic energy that is normally wasted as pressure losses within the MMR pipelines. A hydraulic model of the pipeline was developed using EPANET, with actual design data serving as input. Four operational scenarios were evaluated (1.2, 1.3, 2.0, and 2.5 MCMD), and the results were analyzed to estimate recoverable energy and identify suitable turbine types. The methodology included simulation of head and pressure distributions, energy recovery calculations, and comparison with the system’s electricity consumption. The study found that at current operating flows (1.2–1.3 MCMD), turbines could recover between 686 and 733 MWh/day, meeting nearly half of the system’s electricity demand. At the original design capacity of 2.0 MCMD, recovery declined to about 610 MWh/day, while at 2.5 MCMD the net gain dropped to only 117 MWh/day due to pumping requirements. Francis turbines were identified as the most practical technology, with Pelton turbines as secondary options in high-head conditions. The research demonstrates that hydropower recovery from the MMR is technically feasible and environmentally beneficial. It could substantially reduce CO₂ emissions and strengthen Libya’s energy security by integrating renewable power directly into the national grid.
Copyright (c) 2026 https://creativecommons.org/licenses/by-nc/4.0
Estimation and stability study of oleuropein from olive leaves extract (Olea europaea)
This study included extraction and estimation of oleuropein concentration in different types of olive leaves. It is the most important medicinal plants which is widely distributed in Libya and used in folklore medicine. The effect of different parameters (solvent, temperature, pH, extraction method and time) during and after extraction was studied. The obtained results showed that Chemlel and Corantina olive leaves have the highest oleuropein amount. In addition, the ideal conditions for extraction and maintaining the stability of the compound when using dioxane as a solvent were: 60% dioxane at 25°C and pH 3, and the soxhlet method is better than maceration.
Copyright (c) 2023 https://creativecommons.org/licenses/by-nc/4.0
Study the effect of surfactants on Emulsion Copolymerization rate of P-Methyl Styrene with Methyl Methacrylate
Two different types of surfactants one ionic surfactant and the non-ionic surfactant were used in this stage. The surfactants were dodecyl sulfate (SDS) and Sorbitan monooleate (Span 80) respectively. The kinetic study was carried out in PMMA seeded growth with the two different surfactants and it found that the conversion time of monomer into the polymer with span 80 was longer than the conversion time with SDS. Emulsion Copolymerization of P-Methyl Styrene with Methyl Methacrylate takes place in a two stage seeded emulsion polymerization. The synthesis of the polymer was done in the presence of surfactants. The initial stage involves the synthesis of PMMA particles through the use of emulsion polymerization reaction using dodecyl sulfate (SDS). The second stage involves the synthesis of PMMA–PPMS composite polymer particles. The PMMA particles will act as the seeds in the second
Effect of Phase Change Material on the Performance of a Packed Bed for Cool Latent Heat Storage Systems
This paper introduces a mathematical and numerical analysis of a packed bed containing spherical capsules filled with phase change material (PCM) for latent cool thermal energy storage (TES). The considered bed is the cylindrical tank and containing spherical capsules arranged in a random form. According to the energy balance on the PCM and the heat transfer fluid (HTF), the governing equations and boundary conditions are derived at transient conditions and used a continuous phase model in this model; the spherical capsules are assumed to behave as a continuous medium. The governing equations of the HTF and PCM are discretized using the implicit finite difference approach and central difference approximation. The resulting algebraic equations were solved used MATLAB program. The numerical results are obtained to study the effects of phase change material on the temperature distribution and energy stored in the bed in both charging and discharging modes.
The Use of Internet of Things Applications in University Education from the Perspective of Faculty Members
With the tremendous development in the context of information technology and digital technologies in all fields, many educational institutions in developed countries have begun to realize the importance of Internet of Things technologies in their educational institutions. It has become necessary to keep pace with these developments and apply Internet of Things technologies, and to prepare university professors and students for these modern technologies. Despite the importance of using and the impact of the Internet of Things in the field of education, the Internet of Things will significantly change the way educational institutions and universities operate. The study aims to integrate and use Internet of Things technologies in the educational process in university education by knowing the degree of readiness of Libyan universities to integrate the Internet of Things into the educational process, and using new technologies for interaction between students and faculty members. According to Baqari [2], and to achieve the objectives of the study, the descriptive analytical method was used, through the application of a 42-item questionnaire to a sample consisting of 87 members of the teaching staff in Libyan universities, after verifying its validity by presenting it to a number of (3) arbitrators from the Faculty of Engineering at the University of Tripoli and the Faculty of Electronic Technology with experience and specialization in the field of information technology. The study included three main axes representing the requirements for using Internet of Things technologies, the importance of Internet of Things technologies, and the attitudes towards Internet of Things in the educational process. The results of the study showed that the sample individuals agreed to a low degree on the requirements for using Internet of Things technologies, the agreement of the sample individuals on the requirements of the importance of Internet of Things technologies came to a high degree, and the degree of agreement on the obstacles of Internet of Things came high, and it was also revealed that there were no statistically significant differences between the responses of the sample individuals to the requirements of using Internet of Things applications according to the opinions of faculty members in university education. The study recommended the necessity of developing the infrastructure and providing the necessary resources to employ Internet of Things applications in Libyan universities.
Computer Science, Artificial Intelligence & Data Science
Study of Langmuir, Freundlich and Dubinin-Radushkevich Adsorption Isotherm Models for Lead and Copper Ions from Aqueous Solutions Using Moringa Seed Powder
Adsorption technology is considered one of the most important techniques used in treating water pollution problems, due to its high efficiency, simplicity of the technology used, and limited cost. This study addressed the adsorption of lead and copper elements in solutions using Moringa seed powder as an adsorbent material. The experiment was conducted in the laboratories of the Oil Research Center, where the adsorption of some heavy elements (lead and copper) from their aqueous solutions was tested. The adsorption process was subjected to adsorption equations (Langmuir - Freundlich and Dubinin-Radushkevich D-R), and all equations gave a good description of the interaction of the studied elements on the surfaces of Moringa seeds, in order to study the equilibrium process of these elements. It was found that the Langmuir and Freundlich models are more suitable in explaining the adsorption of these elements through the correlation coefficient R² values (which were 0.9991, 0.9971, 0.9844, and 0.8675) for the Langmuir and Freundlich models for lead and copper ions respectively, while they were 0.7807 and 0.674 in the Dubinin-Radushkevich model. The two elements under study also varied in their preference for adsorption surfaces, where the lead ion excelled in adsorption on the surfaces of Moringa seeds over the copper ion, which gave a lower adsorption percentage.
Using Stable Isotopes of the Water Molecule (δ²H / δ¹⁸O) to Study Groundwater Recharge Methods and the Extent of Seawater Intrusion into Groundwater in the West Coast Region of Libya
This study has been conducted in the West Coast region / Libya, which is located about 45 km west of Tripoli city, which stretches from Sabratha west to Joudaim east, between longitudes of (12.425–13.025) and latitudes of (32.675–32.825). An isotopic study was carried out for 40 samples of groundwater (which were randomly selected) which distributed in four sections within the study area, in order to study the stable isotopes of the water molecule (δ¹⁸O), (δ²H), which gives evidence of groundwater charging methods and an indication of the influence of seawater intrusion into groundwater. This study suggests that the infiltration of non-evaporated rain water is the main origin of the groundwater in the study area. It also showed the presence of dissolution processes for some components of the reservoir rocks, which affected the increase in salinization of groundwater. Moreover, the obtained results reveal that the stable isotopes (δ¹⁸O), (δ²H) composition of groundwater samples showed that a few samples of groundwater have been affected by the interference of sea water, which are near the coast of the sea, while the rest of...
Al-Hadi Ahmed Abdallah Al-Shakl Al-Shakl
Comparison of PET Bottle Structure Performance Based on Finite Element Method (FEM)
In recent years, Polyethylene Terephthalate (PET) has become one of the most widely used polymers after polyethylene (PE) and polypropylene (PP) in several applications. The manufacture of water and juice bottles is one of the most important of these applications due to its physical properties such as transparency, hardness, and chemical properties, as it is considered chemically inert. In this research, two shapes, square and circular, were studied for a 7-liter bottle, which is used locally in bottling drinking water in abundance, by analysing its behaviour in the case of top loading through stress distribution and its effect on the bottle structure to ensure good performance with less usage weight of PET in order to have less impact on the environment. The structural performance of different bottle designs was studied using the Finite Element Method (FEM) with Abaqus software. The results has shown that, the bottle with a circular shape is better than the bottle with a square shape through its resistance to the upper load and the uniformity of the distribution of stresses on the bottle structure due to the similarity of the dimensions from the center of the bottle and the absence of a sudden difference in the dimensions of the design unlike the square shape.
Density Functional Theory for the Effect of Internal Energy and Dipole Moment on the Absorptivity of Heavy Elements Using Hydroxylated Iron(III) Oxide and Iron(II) Oxide Compounds
This study concluded that the hydroxylated iron(III) oxide compound Fe₃O₂(OH)₃ obtained more stable energy results than alone, and it was = -1962.811766411 Hartree, and in the case of merging with heavy elements, it was better stability than the state of iron(II) oxide Fe₂O₃, and this characteristic of these results in particular gives the preference in using it in the reaction and extracting heavy elements from an environment polluted with them. Also, the dipole moment results = 3.505542 Debye and ultraviolet absorptivity = 7289.97 nanometer, which is better than the state of iron(II) oxide compound Fe₂O₃ alone and combined with heavy elements in this study.
The Importance of Basic Elements in the Research Methodology Section of Scientific Writing
The content of "Materials and Methods" in the research paper provides the information through which the validity of the paper is judged. Therefore, the researcher is required to provide a clear and accurate description of how experiments or studies are conducted, and to rely on a logical basis to justify the choice of experimental procedures taken to answer the research question in a direct and organized scientific writing. Despite the abundance of scientific output in the Arabic language, it lacks the precision and quality in managing the content of the research methodology that precedes the results. The absence of basic scientific and logical narrative leads the reader to question the clarity of the method of reaching the results and perhaps the inability to benefit from the paper's content. Since there is a scarcity of focus on this topic in Arabic scientific research literature, and the research methodology is often presented as a simple and general part when discussing the writing of research papers, this paper will present a precise and specific scientific methodology in the Arabic language for writing the research methodology in scientific papers. Providing a clear and accurate description of how the study or research is conducted, especially quantitative research in applied sciences and engineering, supported by the logical scientific basis for conducting it, is one of the critical aspects of the quality of scientific writing.
Machine Vision System for Industrial Engineering and Its Applications
This paper describes how to develop a machine vision (MV) system. The goal of machine vision system is to reduce human error and inspection time. The applications of MV will increase as a result of the decrease in price in MV equipment. In general there are three primary areas to apply MV which are measurement, inspection and guidance. MV measurement systems measure the two dimensions or three dimensions by enhancing and processing the digital image of the objects under investigation. Inspection systems compare the objects with a pre-stored images. Guidance systems instruct a machine to execute specific actions based on what it perceives. Today many production lines use automation to do repetitive tasks quickly and efficiently. Machine vision has been used statistical, mathematical, or trial and error methods to extract useful information from the captured images. Several mathematical and statistical methods has been used in MV such as Histogram Equalization, Probability and Statistics, Fourier Transforms, Differential Equations, Integration, Matrix and Algebra. The paper presents a concise overview of how to design a proper machine vision system and the tools that required to achieve this task. Also this paper shows some of the application of Machine vision system in Industrial Engineering.
STUDY EXACT SOLUTIONS AND ANALYTICAL OF LINEAR VIE’S USING NON-POLYNOMIAL SPLINE FUNCTIONS
في هذه الورقة البحثية تم تطبيق كل من دوال السبلاين غير متعددة الحدود الخطية والتربيعية لإيجاد الحل العددي لمعادلات فولتيرا التكاملية (VIEs). وقد تم اقتراح خوارزميات جديدة لأول مرة، وهو ما يُعد عنصرًا أساسيًا في هذا العمل. في القسم (2)، تم حل معادلات فولتيرا التكاملية الخطية من النوع الثاني باستخدام دوال السبلاين غير متعددة الحدود الخطية والتربيعية في القسمين الفرعيين (2.1) و(2.2) على التوالي. وفي القسم (3)، تم تقديم حل معادلات فولتيرا التكاملية الخطية من النوع الأول عندما تكون k(x, x) ≠ 0. أما في القسم (4)، فقد استُخدمت دوال السبلاين غير متعددة الحدود الخطية والتربيعية لحل معادلات فولتيرا التكاملية ذات النواة ضعيفة التفرد في القسمين الفرعيين (4.1) و(4.2) على التوالي. وفي القسم (5)، عُرضت أمثلة عددية للتوضيح والمقارنة بين الطريقة المقترحة ودالة السبلاين متعددة الحدود وطرق معروفة أخرى. وأخيرًا، تضمن القسم (6) مناقشة لنتائج الدراسة. تم تطوير خوارزمية لحل هذه المعادلات باستخدام برمجة MATLAB.
Effect of Gradual Punch Speed Variation on Thinning and Springback in Deep Drawing Using Finite Element Analysis
Deep drawing is one of the primary sheet metal forming processes used to manufacture three-dimensional components for various industries such as automotive and household appliances. Among the major challenges associated with this process are maintaining uniform thickness distribution and reducing springback, due to their direct effect on the quality of the final product. This study aims to analyze the effect of gradually varying punch speed during the deep drawing process on thickness distribution and springback using ABAQUS software based on the finite element method (FEM). A three-dimensional numerical model of the process was developed by defining the mechanical properties of the material, the friction coefficient, and the die geometry. Different gradually varying punch speeds were applied and compared with the constant punch speed condition. The results showed that the gradual speed variation improved thickness distribution by approximately 5% compared with the constant speed case. However, the high constant punch speed achieved the lowest springback value, reducing it by 9.5% compared with the gradual speed reduction condition. Furthermore, Speed control contributed to reducing stress concentration in critical regions, particularly at corner areas. The findings highlight the importance of numerical simulation as an effective tool for optimizing process parameters, reducing manufacturing cost, and improving the quality of final industrial products.
Copyright (c) 2026 Libya Journal of Applied Sciences and Technology https://creativecommons.org/licenses/by-nc/4.0
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.