Sana'a University Journal of Applied Sciences and Technology

The Burke-Shaw model (BSM), which is grounded in the Lorenz system, is essential in various areas of physics and engineering. In this paper, we investigate the application of a fractional derivative with a Mittag Leffler (M-L) type kernel to address the existence, uniqueness, and Hyers-Ulam stability (HUS) of solutions for the fractional-order BSM. We utilize the ABC-fractional derivative, developed by Atangana and Baleanu, as it offers a more adaptable approach suitable for a diverse array of real-world applications. To demonstrate the existence and uniqueness of solutions, as well as HUS, we introduce a set of necessary conditions that ensure the results presented in this study.

Power electronics and high-power semiconductor devices are of great importance in the national economy and are closely related to other industries. They can be considered a supporting infrastructure that ensures the functioning of different sectors of the economy. Currently, the main consumer of power electronics products is the manufacturing industry. In the future, the automotive industry may take the palm from it - due to the expansion of the use of electric/hybrid cars, as well as autonomous vehicles. The paper points out the relevance of power electronics to various industries and also assesses the transition from silicon-based devices to the advanced GaN and SiC technologies. The review looks at the trends in the power electronics market, with special attention to industrial and automotive, together with a glance at the growth in demand derived fromelectric and hybrid vehicles. Aside from that, further development of GaN-on-SiC technology and its prospects for application to high-power electronic devices are included in this work.

Enterprises are human resources that are formed into organizational structures and consume material and financial resources to provide society with service or product. Enterprises are constantly changing to keep pace with the changes that occur in the environment of their services or products. There are several techniques and tools that enable an organization to keep pace with the changes occurring in its environment. One of these techniques is business process re-engineering. Business process re-engineering means making a radical modification in the enterprise’s business processes for the enterprise to continue to keep pace with its changing environment. Business process re-engineering is dangerous if it fails. Failure in the task of business processes re-engineering means that the enterprise cannot keep up with the changes and at the same time cannot remain in the state it was in. There are critical success factors in business process re-engineering. Many efforts tried to employ data mining techniques in business processes re-engineering. In this paper, we will propose assessment model to determine the best association mining technique related to business processes re engineering. The proposed assessment model contents of five stages as the following: Data preparation related to business process re-engineering, Algorithm selection, Implementation of selected algorithms, Evaluate the performance related to business process re-engineering, Determining the results. The proposed model aims to implement and examine a set of correlation and association algorithms on an available data set related to business process re-engineering and compare the results based on business processes re-engineering performance factors. The proposed model also relied on mathematical analysis of the algorithms chosen to be implemented in this study. According to that, the methodology using in this study will be based on two stages: The first stage: The methodology of mathematical theoretical analysis for choosing set of algorithms. The second stage: The methodology of experimental implementation and comparison of results based on business processes re engineering performance standards.

Energy Consumption Optimization in the Faculty of Medicine, Sana’a University. The interest of this study is to discover the pattern of energy consumption in the Faculty of Medicine at Sana’a University to reduce energy wastage and enhance efficiency. The study zeroes in on key areas that need optimization in terms of energy use: lighting systems, laboratory equipment, and Heating, Ventilation, and Air Conditioning (HVAC) systems. The strategy to be proposed now will minimize the consumption of energy without affecting the functionality of this faculty by closely analyzing the load profiles and energy audits. This will include upgrading to energy-efficient lighting, optimal equipment scheduling, and adopting energy management systems. This can help the Faculty of Medicine reduce costs related to energy use dramatically, making resource usage more effective and contributing to a better future. The results indicated that these measures can result in considerable cuts in power consumption with maximum estimated savings in electricity up to 59.43%, fuel-57.67, and overall cost-54.61%.

Mixed ligand complexes of fluconazole (FCZ), like the main ligand and glycine (Gly) as the secondary ligand, were synthesized and characterized using elemental analysis, spectroscopy, infrared and electronic spectra, magnetic susceptibility, and molar conductivity. The results showed that 1:1:1 [M:L1:L2] octahedral complexes were formed, with FCZ coordinating through its C=N group and glycine coordinating through its carboxylic oxygen and amino nitrogen. Molar conductivity indicated the complexes were not electrolytic in nature. The antifungal activity of FCZ, glycine, and their metal complexes with Cu, Ni, and Cd was tested against Aspergillus niger, Peni- cillium italicum, and Candida albicans. Cadmium complex [Cd(FCZ)(Gly (H₂O)₂Cl].2H₂O showed significantly enhanced activity with outperforming the standard antifungal agent Nystatin against A. niger and P. italicum. These findings highlight the potential of such complexes as effective antifungal agents.

The nutritional quality of mulberries, particularly their antioxidant content, is vital for human health. Yemen produces mulberries in moderate quantities. This study validated the methods used to measure total antioxidant content (TAC), total polyphenols content (TPC), total flavonoid content (TFC), and vitamin C (Vit. C) in mulberry fruit samples Spectrophotometrically. The results demonstrated high repeatability, with relative standard deviation (% RSD) values ranging from 0.90 to 2.53 % for TAC, 0.65 to 1.87% for TPC, 1.55 to 3.48 % for TFC, and 0.64 to 2.64 % for vit. C. Additionally, the methods showed good linearity correlation coefficients (R²) values of 0.9964, 0.9984, 0.9985, and 0.9987, high sensitivity, LOD values of 0.089, 0.188, 0.585, and 8.070 ppm, respectively; LOQ values of 0.296, 0.630, 2.854, and 26.900 ppm, respectively, and satisfactory accuracy (%R values of 89.66 to 102.78 % for TAC, 99.76 to 105.14% for TPC, 90.93 to 103.66% for TFC, and 92.80 to 98.21% for Vit. C). Analysis of Yemeni mulberry samples revealed TAC values ranging from 3792.00±0.018 to 6333.33±0.027 mg AAE/kg fw, TPC from 1431.50±0.025 to 3729.60±0.007 mg GAE/kg fw, TFC from 215.20±0.051 to 541.85±0.020 mg QE/kg fw, and Vit. C from 410.26±0.100 to 850.82±0.050 mg AAE/kg fw. This study confirms the methods’ validity of antioxidants, which showed high sensitivity, accuracy, good linearity, and repeatability while testing Yemeni mulberry samples. The extracts exhibited high antioxidant activity, with potential applications in the prevention and treatment of oxidative stress-related diseases.

The quality of grapes is an important issue for nutritional value and content of antioxidants, which are essential for human health. Yemen is Famous for growing different types of grapes in large quantities. This study aims to validate the analysis methods of determination of total antioxidants (TAC), polyphenols (TPC), flavonoids (TFC), and vitamin C (Vit. C) contents, in terms of linearity, repeatability, accuracy, and limits of detection (LOD) and quantification (LOQ), for measuring TAC, TPC, TFC, and Vit. C in grape samples, with good linearity (R2) are 0.9968, 0.9967, 0.9971, and 0.9966, exhibited high repeatability(% RSD) are ranged (1.452 – 4.836%), (0.720 – 3.240%), (0.766 - 6.001%), and (0.539-2.976%), also high sensitivity (LOD = 0.279, 0.243, 0.288, and 76.376 ppm), LOQ = (0.928, 0.809, 0.961, and 245.588 ppm), and the high accuracy (%R) (80.80-95.00%), (91.44-104.35%), (92.37-101.87), and (88.89-104.65%), respectively. The analysis results of fourteen Yemeni grape samples indicated that the highest value of TAC for a Black grape sample was 6755.3 mg AAE/kg, while the lowest value for the Asmi grape sample was 1621.7 mg AAE/kg. For the TPC, the highest value was 4718.3 mg GAE/kg for the Black grape whereas the lowest content was 1382.3 mg GAE/kg for the Asmi grape. TFC ranged from 341.8 for the Black grape to 32.0 mg QE /kg for the Asmi grape—lastly, Vit. C ranged from 2418.1mg AAE/kg Black grape to 766.5 mg AAE/kg for Asmi grape. This study indicated that Yemeni grape varieties exhibit high TAC, TPC, TFC, and Vit. C contents, which can be used as a natural source of antioxidants.

The microbiological quality of ice cream produced in Yemen was assessed to evaluate compliance with food safety standards and identify potential health risks. A total of 100 samples were collected from three Yemeni governorates (Sana’a, Ibb, and Hodeidah) and analyzed for aerobic plate count, Enterobacteriaceae, Escherichia coli, Salmonella spp., Staphylococcus aureus, mold, and yeast counts. The results showed that 61% of the samples were contaminated, failing to meet acceptable microbial quality standards. Significant disparities were observed between large and small factories, with 52% of samples from large factories meeting the standards compared to only 26% from small factories (P = 0.013). Escherichia coli contamination was detected in 28% of small factory samples, while yeast and mold contamination was significantly higher in small factories (72%) compared to large factories (36%) (P = 0.013). Packaging type also had a significant impact on microbial quality (P = 0.003), with unpackaged samples showing substantially higher contamination rates than packaged samples. No Salmonella spp. or Staphylococcus aureus was detected in any samples, reflecting effective control of these pathogens. The findings emphasize the importance of implementing stringent hygiene practices and improving microbiological monitoring, especially in small-scale production facilities, to ensure the safety and quality of ice cream in Yemen.

Plastic-covered greenhouses are widely used in Yemen to cultivate various vegetable crops, often without adequate consideration of their microclimatic conditions. This study evaluated the key microclimatic factors affecting plant growth, including air temperature, relative humidity, humidity ratio, and heat content. Air temperature and relative humidity were measured both inside and outside a 36 meter-long plastic-covered greenhouse. Internal measurements were performed at three locations: the entrance, middle, and end sections. Psychrometric equations were used to calculate the humidity ratio and heat content of air. The results indicated that the air temperature inside the greenhouse was lower than outside during the early and late afternoon hours, with a maximum difference of 3.4°C. However, between 8:00 AM and 3:00 PM, the internal temperature exceeded the external temperature, peaking at 7.5°C higher at 11:00 AM. On average, the internal daytime temperature was 25.9°C (ranging from 8.3°C to 34.9°C), while the nighttime average was 11.8°C (ranging from 8.4°C to 19.1°C). The relative humidity inside the greenhouse remained consistently higher than outside, fluctuating between 32% and 84% throughout the day. The average internal daytime relative humidity was 49.7% (ranging from 32.0% to 86.4%), whereas the nighttime average was 76.1% (ranging from 52.3% to 86.3%). The humidity ratio and heat content remained stable at night, but increased significantly during the daytime. A longitudinal variation was observed, with the greenhouse entrance exhibiting a humidity ratio of 4.3 kg of water per kg of air and a heat content of 12.2 kJ/kg, both lower than those recorded in the middle and end sections. The average internal daytime humidity ratio was 13.2 kg of water per kg of air (ranging from 7.7 to 17.5), while the nighttime average was 8.3 kg of water per kg of air (ranging from 7.6 to 9.5). Similarly, the average internal daytime heat content was 59.8 kJ/kg (ranging from 27.8 to 78.2), while the nighttime average was 33.4 kJ/kg (ranging from 27.9 to 43.3). Based on these findings, this study recommends enhancing greenhouse ventilation through mechanical systems powered by solar panels or by optimizing existing natural ventilation methods.

As technological advancements accelerate globally, it is crucial for emerging markets like Yemen to keep up with these changes to make the most of modern technology. In particular, Augmented Reality (AR) technology offers significant potential to improve operations across sectors such as education, healthcare, trade, and tourism. Yemen, despite its developing position in the telecommunications and information technology sectors, is experiencing a recovery in computing services, driven largely by policies that promote local data centers to ensure information security. This proximity to data storage and processing facilities provides a unique opportunity to implement AR more efficiently and effectively. This paper proposes a framework for adopting AR technology using Edge Computing (EC) in Yemen. EC technology allows data to be processed and stored closer to end users, reducing the need to rely on remote data centers and ensuring unique interactive immersive experiences. The proposed framework was built using two established models: The Technology Acceptance Model (TAM) and The Unified Theory of Acceptance and Use of Technology (UTAUT2), informed by on-the-ground insights from key technology and telecom entities in Yemen. The research results showed that Perceived Usefulness and Facilitating Conditions received the highest scores (5/5), indicating their critical role in the adoption of edge computing, while Ease of Use and Social Influence scored lower (3.5/5) due to existing technical and societal limitations.