Sana'a University Journal of Applied Sciences and Technology

Human activities are the primary sources of pollution, the severity of which has increased significantly in recent decades, placing immense pressure on both human societies and coastal ecosystems. Seasonal conditions play a crucial role in determining the spread, dilution, or accumulation of pollutants in marine environments. Consequently, assessing seasonal variations in marine sediments subjected to sewage pollution is essential for understanding the extent of this dynamic impact, which is of paramount importance for evaluating and developing effective management and protection strategies. This study investigates seasonal variations in some of the physicochemical parameters of marine sediments along the coasts of the Al-Mukalla and Burum districts in the Hadhramaut Governorate, Yemen. A range of statistical methods were employed to analyze a comprehensive dataset on marine sediment quality over two seasons. This research aims to provide some necessary insights into the extent of pollution in coastal sediments near sewage outlets and to assess the quality of sediments that serve as habitats for a diverse array of marine organisms. The results indicated temporal and spatial variations in coastal sediment pollution in both regions during both seasons, exceeding Yemeni and international permissible limits. The concentrations of environmental parameters, such as temperature, pH, Ca²⁺, Mg²⁺, Cl^-, HCO₃^-, and SO₄^2- decreased during the first season compared to those during the second. This was accompanied by an increase in both EC and TDS . Overall, this variation may be attributed to its association with varying discharge rates, biological processes, and natural factors affecting the seasons. This also underscores the role of sewage as a primary cause of coastal degradation in marine ecosystems. Such pollution is expected to have significant environmental and health consequences by destroying essential habitat structures (such as coral reefs or seagrass meadows), causing toxicity, impaired growth, and disrupting reproductive processes. In turn, this negatively impacts biodiversity and ecosystem resilience.

أُجري هذا البحث لدراسة تأثير استخدام أنواع من أغطية سطح التربة على حفظ رطوبة التربة وكفاءة استخدام المياه عند زراعة محصول الباميا. تضمنت التجربة أربعة معاملات تجريبية: 1) استخدام تقنية حشوات البوليمر، 2) تغطية التربة بالسماد البلدي، 3) تغطية التربة بمخلفات المزروعات، 4) تغطية التربة بالبولي إيثيلين الأسود، وفي المعاملة التجريبية الخامسة، تم الزراعة بدون تغطية كـ(شاهد التجربة). أظهرت النتائج تفوق معنوي لمعاملتي التغطية بالسماد البلدي، والتغطية بالبولي إيثلين على بقية معاملات التجربة في الحفاظ على رطوبة التربة وزيادة الفترة بين الريات، وتقليل كميات المياه المضافة بنسبة 16.72% مقارنة بشاهد التجربة. كما أظهرت النتائج تفوق معنوي لمعاملة تغطية التربة بالبولي إيثلين على بقية المعاملات في زيادة الانتاجية بنسبة زيادة قدرها 80.12%، تلتها معاملة تغطية التربة بالسماد البلدي بنسبة زيادة قدرها 54.74%، ونتيجة لذلك أظهرت معاملة التغطية بالبولي إيثلين تفوقاً معنوياً على بقية المعاملات في رفع كفاءة استخدام المياه بنسبة قدرها 110.48%، تلتها معاملة التغطية بالسماد البلدي بنسبة زيادة قدرها 80.79%.

Cadmium sulfide cd₁s_1−x nanoparticles were synthesized using a simple and cost-effective hydrothermal method by varying the Cd:S molar ratio to investigate its effect on the photocatalytic degradation of Rhodamine B (Rh-B) in aqueous solution under simulated solar irradiation serves as a model organic pollutant. Structural and morphological characterization using XRD, SEM, and UV–Vis spectroscopy confirmed the particularity of cd₁s_1−x particle with good crystallinity and visible light absorption properties. The photocatalytic efficiency of the cd₁s_1−x nanoparticles exhibited a strong dependence on the sulfur ion concentration, indicating the critical role of precursor ratio in tuning photocatalyst performance. Among the samples, the one prepared with x= 0.3026 exhibited the highest degradation efficiency, achieving nearly complete removal of Rh-B within 73 minutes. The enhanced photocatalytic performance is attributed to the optimized particle size, which improves crystallinity and surface area, facilitating more efficient charge separation, light absorption, and separation of photogenerated charge carriers. This study highlights the crucial role of precursor composition in tailoring the structural and functional properties of cd₁s_1−x nanoparticles, providing a straightforward and scalable approach for developing efficient visible-light-responsive photocatalysts for environmental remediation applications.

Green synthesis offers an environmentally benign approach for producing functional metal oxide nanomaterials. In this study, chamomile extract was employed as a natural reducing and stabilizing agent to synthesize ZnO and MgO nanoparticles under identical reaction conditions. The nanoparticles were prepared at 30 °C for 30 min under neutral pH, followed by heat treatment at 400 °C for five hours to remove residual moisture and promote crystallization. Structural and morphological characteristics were examined using X-ray diffraction (XRD), UV–visible spectroscopy and scanning electron microscopy (SEM). The UV–Vis spectra exhibited characteristic absorption peaks at 369 nm for ZnO and 265 nm for MgO. XRD analysis confirmed the formation of hexagonal wurtzite ZnO and face-centered cubic MgO phases, with calculated crystallite sizes of 8.35 nm and 11.58 nm, respectively. SEM images revealed predominantly spherical ZnO nanoparticles forming agglomerated secondary structures (55–70 nm) and spherical MgO nanoparticles with primary sizes ranging from 60–75 nm. The results demonstrate that chamomile extract serves as an effective biotemplate for controlling the nucleation and growth of ZnO and MgO nanoparticles, leading to well-defined structural and morphological features. This study highlights the potential of plant-mediated synthesis as a sustainable route for producing stable nanomaterials suitable for biomedical and environmental applications, reinforcing the role of green chemistry in advancing eco-friendly nanotechnology.

تُعد عمليتا الدراس والتذرية من أهم العمليات التي تلي حصاد محاصيل الحبوب، ولا تقلان أهمية عن الحصاد نفسه، خاصة في الحيازات الزراعية الصغيرة. وتعتمد هذه العمليات تقليديًا على وسائل يدوية بدائية تتطلب جهدًا عضليًا كبيرًا وزمنًا طويلًا، مما يؤدي إلى ارتفاع التكاليف التشغيلية وانخفاض الكفاءة، فضلًا عن الفاقد الناتج عن نقل المحصول. وانطلاقًا من ذلك، تم تطوير آلة دراس وتذرية ذاتية الحركة ملائمة لصغار المزارعين. هدفت هذه الدراسة إلى تقييم تأثير أربع سرعات دوران للأسطوانة (800، 1000، 1200، 1400 دورة/دقيقة) وأربع معدلات تغذية (20، 25، 30، 35 كغ) على إنتاجية القمح، زمن التشغيل، كفاءة الدراس، استهلاك الطاقة، التكاليف التشغيلية، وكفاءة التنظيف. أظهرت النتائج أن إنتاجية القمح ازدادت بزيادة سرعة الدوران ومعدل التغذية، حيث سُجلت أعلى إنتاجية عند 1400 دورة/دقيقة و35 كغ. كما انخفض زمن التشغيل مع زيادة السرعة وازداد مع زيادة معدل التغذية، وسُجل أقصر زمن تشغيل (39.1 دقيقة) عند 1400 دورة/دقيقة و20 كغ. في المقابل، انخفضت كفاءة الدراس بزيادة السرعة وارتفعت بزيادة معدل التغذية، وبلغت أقصاها (89.2%) عند 800 دورة/دقيقة و35 كغ. كما ازدادت الفاقد، واستهلاك الطاقة، والتكاليف التشغيلية مع زيادة السرعة ومعدل التغذية، بينما انخفضت كفاءة التنظيف. وحقق التشغيل عند 800 دورة/دقيقة و20 كغ أقل فاقد (5.38%)، وأدنى استهلاك للطاقة (41.4 ك·و·س)، وأقل تكلفة تشغيلية، وأعلى كفاءة تنظيف (92.2%). وبناءً عليه، يعتمد اختيار ظروف التشغيل المثلى على الموازنة بين زيادة الإنتاجية وتقليل الفاقد والتكاليف، وقد تحقق أفضل أداء متوازن عند سرعة 800 دورة/دقيقة ومعدل تغذية 20 كغ.

This study characterizes the phytochemical composition of the aqueous gel extract from Aloe perryi Baker, a
medicinal species endemic to Socotra Island, Yemen. The primary objective was to investigate and characterize the functional groups and chemical composition of Aloe perryi aqueous extract as compared with quercetin (standard of flavonoids), gallic acid (standard of phenols), aloin (standard of anthraquinones), and ascorbic acid (standard of antioxidants). Aloe leaves gel was blended, extracted with distilled water using a shaker, filtered, and lyophilized. Then the yield of extract (10%) was subjected to FTIR, GC-MS, and HPLC analysis. FTIR analysis confirmed the presence of phenol & alcohols (OH), alkane (C-H), unsaturated ketone (C=C), carbonyl (C=O), Ether (C-O-C), amine (NH), methyl (CH3) functional groups in the Aloe aqueous extract. GC-MS analysis revealed the presence of alcohols, many alkanes, aldehydes, ketones, aliphatic and aromatic esters, and fatty acids in the Aloe aqueous extract. HPLC emphasized the presence of functional groups by the presence of quercetin (3.59%), gallic acid (5.39%), aloin A (19.27%), and aloin B ( 29.64%) in Aloe extract, but ascorbic acid was not separated during this method. The three approaches (FTIR, GC-MS, HPLC) were complementary to one another in identification and the simple quantification of compounds in Aloe extract.

Automated Examination Systems (AES) are increasingly central to modern assessment, particularly as schools move toward broader digital transformation. Automated Exam Systems (AES) have emerged as transformative tools for improving assessment efficiency, accuracy, and transparency. This study examines how AES are adopted and used in resource-limited Yemeni schools, focusing on the technological, organizational, and environmental factors that shape their performance. It investigates the implementation of AES in Yemeni schools, highlighting applications, challenges, and prospects. A quantitative methodology was employed to collect data from 108 participants, comprising students, supervisors, technicians, and teachers, using structured questionnaires. The Technology-Organization-Environment (TOE) was applied to examine factors affecting AES adoption. Statistical analysis using SPSS, including Pearson correlation, Cronbach’s Alpha, and multiple linear regression, revealed significant relationships between technological, organizational, and human factors and the performance of AES. Key challenges, such as infrastructure limitations, inadequate training, and resistance to change, are discussed, along with practical solutions. The findings provided insights for effective AES implementation and future research directions in the Yemeni educational context.

In this study, three novel organophosphorus Schiff base derivatives (OPC₁–OPC₃) were successfully synthesized by condensing chlorodiphenylphosphine with different Schiff bases derived from various aldehydes and hydrazine derivatives. The structural elucidation of the synthesized compounds was achieved using comprehensive spectroscopic analyses, including FTIR, UV-Vis, and both ¹H and ¹³C NMR spectroscopy. Elemental analysis and physical property measurements further confirmed the proposed molecular structures. Spectroscopic data revealed characteristic azomethine (C=N), phosphorus–carbon (P–C), and phosphorus oxygen (P–O–C) stretching bands, confirming the successful formation of the organophosphorus Schiff base framework. The synthesized compounds were tested for antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus using the agar well diffusion method. The results demonstrated that all compounds exhibited moderate to significant antibacterial activity, with OPC² and OPC³ showing notable inhibition zones compared to OPC₁. These findings suggest that the incorporation of organophosphorus moieties into Schiff base ligands enhances their biological potency and provides a promising route for developing new bioactive organophosphorus materials.

Mineral filler selection significantly influences the mechanical performance and economic efficiency of Hot Mix Asphalt (HMA). This study evaluates two locally available Yemeni fillers, Bajil limestone and Sana’a basalt, to identify a technically and economically optimal alternative for pavement construction. Marshall mix design and standardized laboratory tests were conducted to assess stability, flow, volumetric properties, optimum asphalt content (OAC), and moisture susceptibility. Results indicate that the limestone mixture achieved an OAC of (3.8%), compared to (4.8%) for the basalt mixture, representing a 21% reduction in asphalt binder demand and substantial cost savings. Although basalt provided slightly higher Marshall stability, both mixtures satisfied specification requirements. The limestone mix demonstrated superior moisture resistance, achieving a tensile strength ratio of (90.7%) compared to (82.6%) for basalt. Overall, Bajil limestone provides adequate mechanical performance, improved durability, and enhanced economic efficiency, making it a practical and sustainable alternative filler for asphalt pavement applications in Yemen.

Generative AI Applications have become revolutionary technologies that can help with academic evaluation, educational decision-making, and individualized learning. However, despite their technological potential, many higher education institutions especially those in poor nations continue to struggle with faculty and student acceptance of these applications. This study offers in order to determine crucial success variables impacting the acceptance, use and difficulties of generative AI applications, a thorough analysis of the literature. Research from databases including Google Scholar, Scopus, and IEEE Explore that were published between 2021 and 2025 was chosen. A conceptual model based on organizational, individual/psychological, legal/cultural/social, and technical variables is proposed in this study. It also generates hypotheses and evaluates the importance of crucial success variables. Additionally, it outlines the main obstacles to the acceptance of generative AI applications, as well as their limitations and potential future developments, which present a plethora of chances for the creation of various solutions.