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INCORPORATING DIFFERENT LEVELS OF ADENOSINE WITH TRIS- EGG YOLK AND ANDROMED®DILUENTS USED IN FREEZING SEMEN OF RAMS
(An-Najah National University, 2025-01-30) Khaleel , Mousa
Background: Cryopreservation of ram semen is a pivotal technique in ovine genetic improvement strategies. It accelerates the transmission of superior genetic material to low-productivity flocks, enables the long-term preservation of valuable genetic resources, and mitigates geographical constraints in artificial insemination programs. However, ovine semen cryopreservation still faces challenges related to quality, as ram sperm cells are particularly vulnerable to thermal stress and oxidative damage during freezing. Adenosine, a purine nucleoside, has been shown to enhance cellular metabolism and antioxidant defense; however, its potential application in ovine semen cryopreservation remains underexplored. Aims: This study aims to elucidate the protective effects of adenosine at different concentrations (0%, 0.5%, 0.75%, and 1%) on sperm motility, viability, thermal resistance, membrane integrity, and morphology throughout the freezing process. Additionally, the study compares the efficacy of Andromed® and Tris-egg yolk extenders in maintaining sperm quality. Methods: Semen was collected from six mature Assaf rams aged 3 to 4 years and diluted with adenosine-enriched Andromed® and Tris-egg yolk diluents. Semen samples were evaluated for motility, viability, thermal resistance, membrane integrity, and morphology at three key stages of the freezing process. The data were statistically analyzed using ANOVA to evaluate the effects of adenosine concentration and extender type. Results: Adenosine significantly improved sperm quality at all freezing stages (P < 0.05), with 0.75% yielding the most favorable results. Moreover, Andromed® outperformed Tris-egg yolk in preserving frozen ovine sperm quality (P < 0.05). Conclusion: The incorporation of adenosine into semen extenders, particularly at 0.75%, significantly enhanced the quality of frozen ovine semen. Furthermore, Andromed® proved to be more effective than Tris-egg yolk as freezing extender. These findings provide valuable insights into the application of adenosine in cryopreservation and contribute to improved reproductive efficiency in ovines.
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A COMPARISON OF NUMERICAL SOLUTIONS FOR ONE FREDHOLM INTEGRAL EQUATIONS SYSTEM OF THE SECOND KIND
(An-Najah National University, 2025-02-06) Badrien, Mohammed
The main goal of this work is to propose various numerical techniques for approximating the solution of a system of Fredholm integral equations of the second kind. The methods proposed involve the Chebyshev collocation method, the Haar wavelet method and the reconstruction of the variational iteration method. After reviewing the basic concepts of Fredholm integral equations and addressing the mathematical framework of these numerical methods, we provide some illustrative numerical examples with known exact solution to illustrate the effectiveness and the efficiency of these methods. Numerical results show clearly that Chebyshev collocation method is one of the most efficient method for solving system of Fredholm integral equations in comparison with its counterparts.
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INNOVATING DAIRY ALTERNATIVES: THE PRODUCTION AND EVALUATION OF PLANT-BASED YOGURT SUBSTITUTES
(An-Najah National University, 2025-02-26) Ibrahim, Ayah
Background The demand for plant-based food alternatives has increased in recent years, driven by growing health consciousness, and environmental concerns. Among these alternatives, plant-based yogurt has become increasingly popular as a dairy substitute. Objectives The primary objective of this study is to evaluate the impact of blending four distinct plant-based milk varieties (oat milk (OM), almond milk (AM), coconut milk (CM), and quinoa milk (QM)) at varying concentrations on the physicochemical properties and sensory and nutritional characteristics of plant-based yogurt following fermentation with lactic acid bacteria. Methodology Various plant-based milks were selected for yogurt production and blended at different ration (T1: 30% OM, 30% AM, 20% CM, 20% QM, T2: 30% OM, 20% AM, 40% CM, 10% QM, T3: 50% OM, 25% AM, 15% CM, 10% QM, T4: 30% OM, 30% AM, 10% CM, 30% QM, T5: 25% OM, 20% AM, 35% CM, 20% QM). The blended plant-based milk were fermented by using (Lactobacillus Bulgaricus and Streptococcus Salivarius subsp. Thermophilus) at 45°C for 6 h. To avoid the Syneresis phenomena stabilizers, pectin and xanthan gum and their mixture was added. The quality of the milk was assessed through pH measurements, total titratable acidity, and zeta potential particle size and polydispersity index were also measured to ensure the stability of the formulations. Blended plant-based yogurt were evaluated for their viscosity and sensory evaluations and acceptability index. Moreover, the nutritional composition of the blended plant-based yogurts was analyzed. Results The plant-based milk was successfully extracted and blended in different ratios. Fermentation ended when the pH reached 4.6. Before fermentation, the acidity ranged from 0.04% to 0.6% as lactic acid, increasing to 0.15%–0.2% during fermentation. T1 had the highest acidity due to its 30% oat and 30% almond milk, while T2 had the lowest with 40% coconut milk and 30% oat milk. Stabilizer addition influenced zeta potential and particle size. Xanthan gum alone significantly improved zeta potential and reduced particle size in T1 and T2 compared to pectin alone or their combination. However, pectin and xanthan gum together further reduced particle size and enhanced stability in T3, T4, and T5. T5, with 35% coconut and 25% oat milk, was the densest and thickest, whereas T1 had the lowest viscosity. Sensory analysis showed that T3 and T5 scored highest in appearance and viscosity, while T5 had the highest overall acceptance. Nutritionally, T1 had the lowest calorie content (49 kcal), while T1, T3, and T4 had the highest protein content (1.2%–1.3%). Discussion Higher acidity in T1 is likely due to increased fermentable sugars in oat and almond milk, while T2's lower acidity may be attributed to coconut milk’s lower sugar content. Stabilizers influenced texture, with xanthan gum improving stability and the pectin-xanthan combination further enhancing viscosity. Sensory results aligned with physicochemical findings, with T5’s balanced composition (coconut, oat, almond, quinoa) yielding optimal mouthfeel and texture, leading to higher acceptance. The low-calorie content of T1 may appeal to health-conscious consumers, while T1, T3, and T4’s higher protein content suggests nutritional benefits. Overall, formulation significantly affected fermentation, stability, and acceptability, highlighting the potential of optimized plant-based yogurt. Conclusions In this study, oat, almond, coconut, and quinoa milk were combined to successfully create blended plant-based yogurt. It is possible that this plant-based yogurt will be a good substitute for dairy yogurt, especially for customers who are vegan, lactose intolerant, or intolerant to dairy proteins. Upgrading formulations for commercial use and increasing production should be the main goals of future research.
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THE IMPACT OF DEMAND SIDE MANAGEMENT ON THE UTILIYU ACTIONS FOR IMPROVING THE OPERATION OF DISTRIBUTION SYSTEMS CONSISTING PV GENERATOR
(An-najah national university, 2025-02-04) Hanhan, Malaka
This thesis investigates the impact of demand-side management (DSM) strategies on utility actions for improving the operation of distribution systems with high photovoltaic (PV) penetration. A case study was conducted using OpenDSS software, applying the IEEE 30-bus test network. A 50 MW PV system was integrated into bus 21, demonstrating its ability to reduce total electrical losses in transmission lines from 9308.34 kW to 7742.83 kW. Meanwhile, the study examined the application of various DSM strategies to further enhance network performance after hosting the PV system. Direct Load Control (DLC) reduced network losses to 5365.5 kW, while the Time-of-Use (TOU) tariff strategy significantly reduced losses to 3736.9 kW. Additionally, the Conservation Voltage Reduction (CVR) strategy improved overall network voltage profiles, particularly decreasing the voltage at bus 21 from 1.0524 p.u. to 1.0442 p.u. and at bus 11 from 1.0819 p.u. to 1.0748 p.u. The hosting capacity analysis revealed that increasing PV penetration initially reduced electrical losses, with significant reductions observed at penetration levels of 15 MW, 30 MW, 50 MW, and 70 MW, corresponding to losses of approximately 9830 kW, 8000 kW, 7000 kW, and 5800 kW, respectively. However, beyond a hosting capacity of 70 MW, further increases in PV penetration led to a rise in losses, reaching 7900 kW at 150 MW and exceeding 12,200 kW at 200 MW. The use of DSM strategies effectively mitigated these losses even at higher penetration levels. For instance, DLC reduced losses to approximately 6000 kW, and TOU reduced them further to 5000 kW at a 200 MW PV hosting capacity. These findings highlight the critical role of DSM strategies in enhancing the operational efficiency and reliability of distribution systems with high PV integration