United Arab Emirates University
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CFD ANALYSIS OF MULTI-STAGE PHASE CHANGE MATERIAL FOR LATENT THERMAL ENERGY STORAGE IN SOLAR POWER PLANTS
Get PDFThe integration of latent thermal energy storage into concentrated solar power plants represents a promising solution for efficiently harnessing excessive solar energy during daylight hours and subsequently utilizing it during the nighttime when solar energy generation is limited or non-existent, all while catering to consistent energy demands. The core objective of enhancing latent thermal energy storage revolves around elevating its thermal capacity and minimizing the melting time, thus making it a more effective energy storage solution. This is achieved by employing three distinct organic phase change materials: Octadecanoic (PCM1), RT58 (PCM2) and Dodecanoic (PCM3), each characterized by variations in their thermal properties, particularly their melting temperatures. The 3D modeling and simulation of latent thermal energy storage are carried out using Ansys Fluent, with the heat transfer fluid being air or water and the phase change material being housed within sealed containers. During the charging process, the hot fluid is used to elevate the temperature of the phase change material, storing thermal energy by transitioning its phase from a solid to a liquid state. Furthermore, the determination of the optimal thermal energy storage efficiency necessitates exploring how alterations in geometrical configurations and operational conditions, such as temperature and velocity, impact overall system efficiency. In this extensive investigation, the utilization of a combination of three distinct organic phase change materials in the latent thermal energy storage system has demonstrated a significant reduction in melting time by 15.5% and increases efficiency by 6.9% compared to a configuration with a single PCM in each container. Elevating the temperature of the incoming heat transfer fluid by half has proven to be a crucial factor, resulting in a reduction in the melting time by 56% and increases efficiency by 7.8%. However, it is essential to note that increasing the velocity of the HTF by 22.2% decreases melting time by 10% but lowers efficiency by 1.1%. The substitution of water for air as the HTF has shown remarkable improvements reduction in melting time by 67.6% and increases efficiency by 8.2%. Model 2 increases melting time by 10% and efficiency by 0.9%
THE IMPACT OF OUTDOOR THERMAL COMFORT ON USERS’ WALKABILITY: STUDY CASE IN AL AIN SQUARE, AL AIN CITY, UAE
Get PDFLiving in a hot dry arid climate limits the walkability of its inhabitants. The excessive heat and dryness of the weather undoubtedly make walking a less tempting, encouraging, and pleasant choice for getting around the city. For that reason, this master thesis analyzes the various strategies used to enhance outdoor thermal comfort. Outdoor thermal comfort is controlled by numerous factors, including street and building orientation, vegetation, shading devices, and water bodies. The purpose of this study is to examine the relationship between walkability and UTCI values (universal thermal comfort index) in the context of Al Ain Square, a neighborhood in Al Ain City, UAE. The study employed a mixed-methods approach to investigate the relationship between outdoor thermal comfort and walkability in Al Ain City. Firstly, ENVI-met simulations were conducted to model various scenarios, including the base case, the addition of vegetation, the addition of water bodies, and a combination of both. These simulations helped assess the impact of different environmental factors on thermal comfort. Additionally, field measurements were conducted using HOBO sensors placed strategically across the neighborhood to gather real-time data on temperature and humidity levels. The collected data from both simulations and field measurements were then analyzed to draw correlations between outdoor thermal comfort and walkability. The results of the study indicate that integrating vegetation and water bodies in urban environments can significantly improve outdoor thermal comfort, thus promoting walkability. This research aims to identify effective strategies for enhancing outdoor thermal comfort in urban environments, specifically focusing on the role of vegetation and water bodies. Also, the study offers insights into the relationship between outdoor thermal comfort, pedestrian walkability, and urban design elements. This research will provide recommendations for architects, urban planners, and policymakers on integrating climate-sensitive design strategies into urban development projects, which will lead to a contribution to the promotion of sustainable transportation modes by creating more walkable and comfortable urban spaces, and enhance the overall well-being of city residents through improved outdoor environments that support physical activity and social interaction
THE ANTICANCER ACTIVITY OF NOVEL 8-HYDROXYQUINOLINE DERIVATIVES AGAINST 5-FLUOROURACIL RESISTANT COLORECTAL CANCER CELLS
Get PDFCancer is a global health crisis for which 20 million new cases were diagnosed in 2022 alone, with 9.3 million cancer-related deaths. Nearly 900,000 deaths were due to colorectal cancer (CRC), which is the third leading cause of cancer related mortality. In the United Arab Emirates, 550 new cases of CRC were reported in 2022. A major clinical challenge with CRC treatment is the development of resistance to 5-fluorouracil (5FU)-based chemotherapy regimens, which are the standard treatment for CRC. In the present study, the anticancer activity of two novel 8-hydroxyquinoline (8-HQ) derivatives AS45 and AS47 was examined against 5FU-sensitive (HCT116) and 5FU-resistant (5FU-R-HCT116) human CRC cell lines. Both 8-HQ derivatives were found to inhibit the viability as well as the colony formation ability of HCT116 and 5FU-R-HCT116 cells. Based on the results of both viability and colony formation assay, AS47 was selected as the candidate 8HQ derivative with potent activity. Further analysis revealed AS47 induced senescence in HCT116 cells, as confirmed by positive staining for senescence-associated β-galactosidase and downregulation of cell cycle associated protein cyclin D1 and the upregulation of p21 and p27. In contrast, AS47 induced autophagy in 5FU-R-HCT116 cells, which was confirmed by accumulation of LC3B-II on western blotting. Lastly, AS47 could inhibit the migratory capacity of both cell lines, demonstrated its ability to prevent wound closure in wound healing assay. Our collective data suggest that the novel 8-HQ derivative AS47 is a promising anticancer agent for both 5FU-sensitive and 5FU-resistant CRC and should be studied further
THE PREDICATE CRIME AS A PRESUMPTIVE CONDITION FOR THE CRIME OF MONEY
Get PDFThe crime of money laundering is closely linked to the crime from which the funds being laundered are obtained. There is no talk of money laundering without funds derived from an illicit source. Hence, the question arises about the nature of the original crime, and whether it includes every crime from which illicit funds arise, or whether the matter is limited to specific crimes, as the crime of money laundering is an affiliated crime in nature and its legal structure is not complete unless the original crime occurs. The federal legislator, in accordance with the second paragraph of Article 2 of Federal Decree Law No. (26) of 2021, amending some articles of Federal Decree Law No. 20 of 2018 regarding combating money laundering crimes and combating the financing of terrorism and financing illegal organizations, considered that “the crime of money laundering is considered a crime.” Independently”, and punishing the perpetrator of the original crime does not prevent from being punished for the crime of money laundering.” In this study, attention was paid to determining the extent of the independence of the crime of money laundering from the original crime as a presumptive condition, as well as the sources on which proof of the crime depends, the source of the funds is illegal, imposing a penalty for the original crime, and imposing a penalty for the crime of money laundering in deviance from the rule of applying the most severe punishment in the state of indivisible connection, and through this we wanted to clarify the validity of the rulings issued in acquittal and conviction in the original crime over the ruling in the crime of money laundering
THE IMPLEMENTATION OF STREAM IN MATHEMATICS CLASSROOMS IN ABU DHABI PRIMARY SCHOOLS: PROSPECTS, PRIORITIES, PROCESSES, AND PROBLEMS
Get PDFThis study shed light on implementing science, technology, reading and writing, engineering, art, and mathematics (STREAM) in mathematics classrooms in Abu Dhabi primary schools. The study aimed to explore mathematics teachers’ views on the prospects, priorities, processes, and problems of the implementation of STREAM in their classrooms. The study employed qualitative methods to collect and analyze data to support the findings using interviews, classroom observations, and document analysis. Fifteen in-service mathematics teachers were interviewed to explore their views about the application of STREAM in their classrooms regarding prospects, priorities, processes, and problems (4 Ps). Then, three of them were observed in their classrooms to collect data about how they integrate mathematics with other STREAM subjects. Also, the researcher analyzed instructional plans, lesson plans, projects, and assignments from eight teachers to find evidence about the implementation of STREAM in mathematics classrooms and its quality. The interviews revealed that mathematics teachers’ prospects of the implementation of STREAM were that it could improve students’ skills and teachers’ practices. The priorities of STREAM in mathematics primary classrooms are integrating mathematics lessons and projects, improving students’ mathematical skills and understanding, and curriculum support for STREAM integration. Mathematics teachers used STREAM pedagogies, such as problem-based, project-based, and design-thinking. The problems with the integration of STREAM in mathematics classrooms are the lack of teachers’ training, materials and resources, and traditional assessment. The classroom observations found no evidence that STREAM improves students’ skills or teachers’ practices. Also, the level of integration is shallow in reading, writing, and arts. Document analysis showed some evidence for the integration of STREAM implementation of STREAM in mathematics classrooms, but it is limited. The research recommended providing mathematics teachers with opportunities for training in STREAM to improve the implementation practices
UTILITY OF NEW REMOTE SENSING DATA IN EVALUATING THE HYDROLOGICAL RESPONSE TO LAND USE AND LAND COVER CHANGES
Get PDFLand use and land-cover (LULC) changes have profound impacts on hydrological responses, influencing runoff dynamics and flood risks. This study focused on two contrasting watersheds undergoing rapid LULC transformations: the arid Wadi Ham watershed in the UAE and the tropical Imphal watershed in India. The research emphasized the critical role of accurate LULC data for hydrological modeling in climate-sensitive regions, where land-use changes are accelerating. Using high-resolution PlanetScope and Sentinel-2 satellite imagery, LULC maps were developed and classified using Maximum Likelihood (ML) and Random Forest (RF) algorithms. PlanetScope imagery paired with the RF classifier achieved the highest overall accuracy, with Wadi Ham’s LULC maps reaching 97.27% and Imphal’s LULC maps achieving 98.59%. Change detection analysis revealed significant transformations, such as an increase in built-up areas in Wadi Ham from 3.63 km² in 2017 to 6.23 km² in 2022, accompanied by a decrease in vegetation from 3.37 km² to 1.56 km². In the Imphal watershed, wasteland expanded significantly from 3.32 km² to 47.14 km², while agricultural land saw notable increases: Kharif crop areas grew from 22.2 km² to 28 km², and double/triple crop areas expanded from 28.23 km² to 38.90 km².
Hydrological modeling using the Gridded Surface Subsurface Hydrological Analysis (GSSHA) model demonstrated the influence of LULC accuracy on runoff simulations. In Wadi Ham, the 2022 simulations, reflecting urbanization, resulted in higher peak discharge (1165.8 CMS at 930 min) compared to 2017 (749.61 CMS at 1037 min). Similarly, in the Imphal watershed, land degradation and agricultural expansion led to increased flood risks, with peak discharge rising from 129.53 CMS in 2017 to 162.33 CMS in 2022. This study highlighted the importance of high-resolution LULC data for reliable hydrological modeling, particularly in data-scarce regions. The findings underscore the need for informed urban planning and flood risk management strategies to mitigate the impacts of rapid land-use changes. By aligning with UAE’s 2030 vision for resilient communities and UN Sustainability Goals 11 (Sustainable Cities and Communities) and 13 (Climate Action), the research contributes to broader global sustainability objectives
REPRODUCTIVE BIOLOGY OF THE JELLYFISH OUTBREAK ALONG THE UAE COASTAL WATERS
Get PDFJellyfish are a ubiquitous occurrence in the world’s oceans. During the past decades, dramatic spatial increases and temporal shifts in jellyfish distributions have been reported around the world. The United Arab Emirates (UAE) coastal area also has experienced several blooms along with severe adverse impacts on its economic facilities. Few studies have been conducted within the Arabian Gulf and the Sea of Oman, to identify the blooming species and the environmental parameters that favor such breakouts. The present study aimed to identify the jellyfish species found along the coastal area of UAE and trying to link their occurrence with seasonal variations in environmental parameters during the period from December 2019 until August 2022. Another objective of this study was to increase knowledge on the mechanisms leading to the proliferation of the two most common jellyfish species along the study area i.e. Catostylus mosaicus, and Cassiopea andromeda. Morphological analysis and molecular confirmation were used to identify these two species. Moreover, histological and biochemical analyses of the gonads were carried out to understand the seasonal variations in the reproductive biology of the two-dominant species. During the study period, six species have been identified as Catostylus mosaicus, Cassiopea andromeda, Aurelia aurita, Chrysaora quinquecirrha, Cephea cephea and Carybdea sivickisi. The spatial and temporal occurrence of all identified species have been discussed in light of the monthly temperature variations during the study period. The obtained results indicated that the Gonadosomatic Index (GS-I) of the two-dominant species showed a well-defined fluctuation throughout the study period. Indeed, gametogenesis resembled descriptions for other rhizostomes and semaeostomes which can reproduce throughout the year with higher rate fluctuations in carbohydrates, protein and lipid concentrations too. This research represents the most comprehensive study of jellyfish along the UAE coastal area. From the obtained results and observations, the need for continuous monitoring of jellyfish blooms as well as surveying for new species introduction to the Arabian Gulf and the study of its habitat and its reproduction and feeding habits are recommended. This will be helpful in predicting any negative impact of its blooming, and to face the consequences by taking enough precautionary measures
HUMAN RESOURCE PRACTICES AND EMPLOYEE OUTCOMES: AN EXAMINATION OF PERFORMANCE, SATISFACTION AND DIVERSITY CLIMATE IN THE HOSPITALITY SECTOR OF SAUDI ARABIA
Get PDFTourism and related industries have become essential economic activities that play a significant role in the development, prosperity, and well-being of a country. The tourism and hotel sector in the Kingdom of Saudi Arabia (KSA) is currently undergoing significant development to diversify the national economy in line with the KSA Economic Vision 2030 Initiative. To align this sector with international standards in terms of job satisfaction and performance, human resource management practices (HRMPs) play a key role in determining the job satisfaction of employees in their various work environments. HRMPs include various job-related activities, training and development (T+D) programs, rewards, performance management, and promoting participation. The main focus of HRMPs is, therefore, to develop employees and create a positive work environment. Although there is active academic research worldwide on the potential relationship between HRMPs and employee performance, little has been written about this relationship in the Saudi hotel industry. This study examines the relationship between the four HRMPs and job performance of employees based on job satisfaction, particularly attention to the impact of different work climates. A quantitative research design was used to obtain data from hotel sector managers in the KSA. Probability sampling was used to collect data from four cities in Saudi Arabia. Data was collected from 700 participants using a questionnaire. In addition, the structural equation modeling (SEM) technique was used to test the validity of the study\u27s measurement and structural model using SMART-PLS. The measurement model of SEM confirmed the reliability and validity. The results obtained showed that HRMPs have a positive relationship with employee job satisfaction and performance. Furthermore, employee job satisfaction moderates the relationship between HRMPs and employee job performance, while the diversity climate also plays an important moderating role in this relationship. The current study contributes to social exchange theory (SET). The practical implications are that the HRM managers in the hotel industry will gain insights from this study about the positive impact of HRMPs on employee job satisfaction and performance in the KSA hotel industry
INVESTIGATING THE EFFECT OF ACTIVE LIVING WALL ON INDOOR AIR QUALITY AND ENERGY CONSUMPTION: CASE STUDY IN UAEU CLOSED OFFICES
Get PDFExtreme hot climates can significantly affect Indoor Air Quality (IAQ) and ventilation, resulting in higher energy demands. Numerous studies have demonstrated that outdoor greening, such as trees and landscaped areas, can reduce a building’s energy consumption. However, less research has been conducted on the impact of indoor vegetation on energy use and air quality. Indoor vegetation decreases Carbon Dioxide (CO₂) concentration by absorbing CO₂ and releasing oxygen (O₂), while the evapotranspiration process further enhances (IAQ) and reduces energy expenditure. The United Arab Emirates has dry arid climate and summers with high humidity levels, causing individuals to stay longer indoors, which is leading to an increase in energy usage and high cooling demands resulting from global warming and climate change. This feasibility study explores the impacts of indoor planting on IAQ and energy consumption through the implementation of Active Living Wall (ALW) during the fall and winter seasons across several offices at the United Arab Emirates University (UAEU) in Al Ain. To evaluate the ALW impacts on IAQ and potential energy reduction, IAQ monitoring for selected offices was conducted along with a survey and interviews to gather user-side evaluations. CFD and energy simulations were also performed to analyses the effects of ALW on airflow and cooling load demand. Results indicate a temperature reduction of 0.3°C to 1.0°C across different fan speeds. Additionally, ALW enhanced IAQ by reducing CO₂, PM10, PM2.5, and Total Volatile Organic Compounds (TVOC), with CO₂ levels reduced by up to 100 ppm and TVOC reduced up to 9.8 μg/m³. Limitations include the structural design of the ALW and the chosen plant types in indoor conditions. ALWs improves human comfort which reduces the health effects of Sick Building Syndromes (SBS). Further research should explore the long-term effects of ALWs to effectively address climate change challenges
ضوابط استخدام تقنية النانو في المجال الطبي: دراسة تأصيلية
Get PDFThe idea of this research is about the Nanotechnology\u27s concept and applications in the Contemporary medical field, with presenting the benefits and the evils of this technology.
The research aimed at clarifying the legal rules of this issue citing evidence the legal evidence, the objectives of the Sharia, and the legitimacy rules.
In this research I\u27ve followed the inductive approach to collect the data and the information that is relevant to the topic, As well as the descriptive approach to illustrate the issue from the expert point of view, in addition the analytical approach to break the topic into issues to analyses, and compare between the scholars opinions in these jurisprudence issues, and to set the standards of using this technology.
Findings of the research led to prefer allowing the use of technology in medicine fields according to the legal evidence and the Sharia\u27s objectives, as well as the interests that are achieved by using the nanotechnology in medicine.
تقوم الدراسة حول بيان مفهوم تقنية النانو وتطبيقاتها الطبية المعاصرة، وما تنطوي عليه هذه التقنية من مصالح ومفاسد، كما تهدفُ إلى توظيف النظر الاجتهادي في المسألة بالاستهداء بالأدلة العامة، والمقاصد الشرعية، والقواعد الفقهيّة تمهيدًا لبيان الحكم الشرعي في المسألة.
وقد اتبعتُ في هذا البحث المنهج الاستقرائي بتتبع المادة العلمية من مظانها، والمنهج الوصفي لوصف المسألة وفق ما قرره أهل الخبرة والاختصاص، واستعنت بالمنهج التحليلي لتحليل الأدلة والنصوص والنظر في المقاصد الشرعية والقواعد الفقهية؛ لاستنباط الحكم الشرعي للمسألة، واستجلاء ضوابط العلاج بهذه التقنية.
وخلصتُ في نهاية البحث إلى عدد من النتائج من أهمّها: ترجيح القول بجواز العلاج بهذه التقنية بعد النظر في الأدلة والمقاصد الشرعية، والاستئناس بالقواعد الفقهية، وأن هذا العلاج يترتب عليه مصالح ترجع في مجملها إلى رعاية مقصود شرعي