Single plate analysis of thermoacoustic refrigerator

IJTEE, Volume-20 , Issue 1 (2023), PP 13 - 19

Published: 07 Feb 2023

DOI: 10.5383/ijtee.20.01.003

by Omar Al-Mufti and Isam Janajreh from Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi, UAE

Abstract: Thermoacoustic refrigerator (TAR) or heat pump is a device that uses acoustic sound to pump heat from a lower temperature reservoir. The most distinct feature of thermoacoustic systems is that they do not have moving parts, which makes them reliable with no to low maintenance. TAR can be driven using thermoacoustic engine (TAE) in which the later can be sustainably operated utilizing waste heat or concentrated solar. Also, in contrary to conventional refrigeration methods, TARs do not use environmentally harmful gasses. In this work, a high-fidelity localized model is developed to simulate the flow in a standing wave (straight tabular) thermoacoustic refrigerator. In this localized analysis a subsection domain that runs through two stack halves and stretches nearly 1.5 stack length at each side is considered. The acoustic waves were simulated using oscillating walls at the two domain limits at a given resonance frequency. The model compared favorably to previous experimental and numerical findings. The analysis was done for drive ratios in range of 0.28% to 2%. A 3.2 oC temperature difference is produced at the 2% drive ratio compared to 0.5 oC at the 0.28% ratio. Higher difference can be achieved at higher drive ratio and also larger stack length. read more... read less...

Keywords: Numerical modeling, Thermoacoustic, Refrigerator, Drive ratio, CFD

Thermal Comfort Analysis of Wind Tower Greenhouse Integration System using Ansys

IJTEE, Volume-20 , Issue 1 (2023), PP 07 - 12

Published: 07 Feb 2023

DOI: 10.5383/ijtee.20.01.002

by Sameer Khan, Ruqiya Abdullah Farah, Isam Janajreh from Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates

Abstract: Increasing urbanization, a shortage of arable land, and climate change-related weather extremes are some of the challenges facing the production of global food and agriculture due to the estimated global population of 9.6 billion by 2050. As a result, improvements in greenhouse technology and modifications pushed science-based solutions for optimal plant production in all seasons worldwide by adjusting internal climate growing factors. By using passive technology coupled with evaporation cooling from wind towers, significant amounts of energy can be saved, reducing the emissions of greenhouse gases. In this study, the effect of wind tower greenhouse integration on the micro-climatic conditions inside the greenhouse is modeled and simulated. The model is governed by the non-isothermal Navier-Stokes flow in heat, viscous and turbulent flow regimes. The effect of various parameters such as airflow velocity, relative humidity, and temperature in the greenhouse is studied as well as the effect of mist flow rate, and the position of the injector in the wind tower. The results show the optimal design of the greenhouse wind tower integrated system based on the desired temperature and relative humidity within the greenhouse. The final model selected was the flat slope geometry greenhouse with a temperature value of 29.839792°C and relative humidity of 68.34%. read more... read less...

Keywords: Ansys, Evaporative Cooling, Greenhouse, Wind tower

Experimental Study on the Effect of Water as a Working Fluid in Aluminium Heat Pipes

IJTEE, Volume-20 , Issue 1 (2023), PP 01 - 05

Published: 07 Feb 2023

DOI: 10.5383/ijtee.20.01.001

by Salman Hemayet Uddin, Md. Islam, Firas Jarrar, Isam Janajreh from Department of Mechanical Engineering, Khalifa University, Abu Dhabi, United Arab Emirates

Abstract: Thermal management of machines and electronic devices is a matter of high importance. Cooling of electronics becomes much more sensitive in applications related to space because of the difficult constraints and environment. The weight and size are very important parameters as well as the efficiency of the cooling method and heat pipes are considered a very suitable option because of its passive operation and light weight. Different working fluids can be used in a heat pipe but the compatibility of the casing material with the working fluid is a very important parameter. Water aluminum heat pipes are not a common option because they react at temperatures starting from 294 K. In this research the effect of water in the degradation of the performance of aluminum heat pipes is studied. A suitable operation range for the heat load is considered. It is found that at higher loads, the performance of the heat pipe decreased but with the addition of nano particles the performance was compensated by a large measure. read more... read less...

Keywords: Aluminum water heat pipe, Grooved Heat pipe, Hydrogen formation in heat pipe, Nanoparticles

Effect of Tree Shape on Micro-Climate Conditions

IJTEE, Volume-19 , Issue 2 (2022), PP 93 - 33

Published: 28 Dec 2022

DOI: 10.5383/ijtee.19.02.006

by Mohamad Alsheikh, Abdelsalam Alkhalaileh, Isam Janajreh from Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi, UAE

Abstract: Optimizing the microclimate conditions has become a very significant demand by public, which led to numerous research in this field. In this study, the effect of different tree shapes and their influence on the microclimate conditions will be studied using computational fluid dynamics (CFD). A baseline geometry was designed with a set of boundaries conditions and its robustness is assessed via different mesh resolutions. Three different tree shapes with the same surface area (long-triangular, short-triangular, and round) were considered and compared. The flow field is governed by the two-dimensional, steady-state, multi-species, and non-isothermal Navier-Stokes equations. In all the tree model configurations, the trees were considered the source of moisture and lower temperature than the surrounding environment. This resulted in increase in the relative humidity of the incoming ambient air and reduction in its temperature. In this analysis the incoming air was considered to follow the common power law atmospheric boundary layer (u/Uinf=(y/Ho)1/7) with an inherited vertical strain rate. The presence of the trees created axial and exaggerated the vertical rate of strains. The results showed that long triangular tree shape had the biggest drop in temperatures with a value of DT= 4.15K (301K local value). It also resulted in a relative humidity value between 15% and 45% which is suitable for the human thermal comfort. read more... read less...

Keywords: Microclimate; CFD; Human thermal comfort; Tree-shape

A Posture Recognition System to Track Drivers’ Activities While Driving

JTTM, volume-03 , Issue 2 (2021), PP 25 - 31

Published: 21 Aug 2021

DOI: 10.5383/JTTM.03.02.004

by Khaled Shaaban, Osama Halabi, Eman Almughani from Utah Valley University, Orem, United States, 84058 and Qatar University, Doha, Qatar, 2713

Abstract: To improve traffic safety, different systems were invented to warn drivers when detecting a conflict. However, drivers may be already aware of such conflicts. In these cases, warning drivers may not effective and may lead drivers to not pay attention to warnings in the case of serious conflicts. The purpose of this study is to develop a novel posture recognition system to detect different driver activities while driving. If drivers are not braking or decelerating in the case of a conflict, they are alerted and notified about the conflict. The proposed system is based on a passive method for measuring bodypostures by using two force sensor arrays to inspect the pressure patterns exhibited in the driver’s seat and backrest. Different sensors' distributions were tested to find the most suitable distribution to improve the accuracy of the recognition. A virtual reality (VR) driving simulation was developed to test the accuracy of recognition in an immersive environment. Experiments were carried out to test the posture recognition accuracy in both realistic and VR settings. The results showed that the system could recognize different postures with high accuracy. Such a system can be used to alert drivers and disengage autonomous mode in the case of self-driving and autonomous vehicles when the situation unsafe. read more... read less...

Keywords: Sitting posture, activity recognition, driving simulator, virtual reality, autonomous vehicles

An integrated agent-based model of travel demand and package deliveries

JTTM, volume-03 , Issue 2 (2021), PP 17 - 24

Published: 18 Aug 2021

DOI: 10.5383/JTTM.03.02.003

by Anna Reiffer, Jelle Kübler , Lars Briem, Martin Kagerbauer, Peter Vortisch from Institute for Transport Studies, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany

Abstract: With the increased shift from in-store shopping to e-commerce, we can expect the share of delivery vehicles in cities to rise as well. This puts great pressure on cities and surrounding areas as emissions rise and space becomes scarce. Because the last leg of the delivery chain is so costly, there have been many studies on how the last-mile issue can be diminished. However, most studies only cover deliveries independently from the orders. This paper presents a modelling approach that integrates travel demand, package orders and subsequent deliveries within the same framework. One of the benefits of the integrated modelling approach is that the model can evaluate the agents’ locations at all times during the simulation. This allows us to model different states of delivery on a microscopic level. We have applied the model to Karlsruhe, Germany with a synthetic population of just over 300.000 agents. The results show that the model simulates both package orders and the subsequent delivery tours realistically. The model framework allows for detailed analysis of delivery states and success rates and can be used for scenario analysis of different delivery methods and changes in online shopping behaviour. read more... read less...

Keywords: last-mile, agent-based, travel demand, urban freight

Measuring Vehicle Speeds, Compliance Rates, and Braking Reaction Times at Level Crossings Using Fixed and Moving Driving Simulators

JTTM, volume-03 , Issue 2 (2021), PP 09 - 16

Published: 13 Aug 2021

DOI: 10.5383/JTTM.03.02.002

by Inhi Kim , Khaled Shaaban from Kongju National University, Chungcheongnam-do, South Korea Utah Valley University, Orem, Utah, United States, 84058

Abstract: Driving simulators are used for many applications including traffic safety. There are several types of driving simulators available for researchers and engineers. This study aims to compare fixed and moving driving simulators in assessing driving behaviors at railway crossings equipped with either typical stop signs or in-vehicle audio safety system. Data used in the comparison included vehicle speed profiles, compliance rates, and braking reaction times. It was found that compliance rates were similar whereas speed profiles and breaking reaction times were slightly different. As the results of the desktop simulator had previously been compared with those from the data collected in the field, the comparison of results between the two simulators reported here can serve as a blueprint to calibrate the use of moving simulators. In summary, the different properties of the simulator can lead drivers to react to warnings differently. read more... read less...

Keywords: Braking reaction time, compliance rates, fixed driving simulator, moving driving simulator, speed profiles

Regionalization for urban air mobility application in metropolitan areas: case studies in San Francisco and New York

JTTM, volume-03 , Issue 2 (2021), PP 01 - 08

Published: 07 Aug 2021

DOI: 10.5383/JTTM.03.02.001

by Namwoo Kim, Yoonjin Yoon from Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141 Korea

Abstract: In a new era of mobility where the transportation of persons or goods via flying vehicles over urban areas has garnered great interest in its application in urban space. With the anticipated utilization of sUAS in urban airspace, a multi-dimensional understanding of urban space is essential. As a first step to assess the feasibility of Urban Air Mobility (UAM) in urban areas, we conduct regionalization and correspondence analysis in highly urbanized areas – San Francisco, CA and Manhattan, NY – by incorporating population dataset and urban 3D airspace to delineate the regional boundaries. Regionalization is carried out using graph-based clustering technique called SKATER (Spatial ‘K’luster Analysis by Tree Edge Removal) to group the regions having similar characteristics and address the compound effect of both population and spatial information. By classifying the regions into five categories through correspondence analysis, the operational and economic feasibility of each region is evaluated. The results provide the region maps of each city with the most and least attractive regions for UAM application with the temporal notion, whether the clusters are daytime-intensive or nighttime-intensive areas. The outcomes have several unique information that can benefit drone delivery target area identification, landing location identification, demand prediction. Our approach can contribute to providing a useful basis for management for UAM in urban areas as well as the process of regulating airspace use. read more... read less...

Keywords: Urban Air Mobility, UAS Traffic Management, Geodemographic Analysis, Spatial Clustering

Enhancement of the TSCH-Sim Simulator via Web Service Interface to Support Co-simulation Optimization

JUSPN, volume-18 , Issue 2 (2023), PP 69 - 76

Published: 02 Apr 2023

DOI: 10.5383/JUSPN.18.02.003

by Tarana Ara, Aida Vatankhah, Ramiro Liscano from Ontario Tech University, Oshawa, Canada, L1G 0C5

Abstract: Co-simulation is an important concept in the optimization of computer networks because a typical optimization scenario integrates an optimization algorithm with a network simulator. In many cases optimization algorithms are implemented in the MATLAB environment while network simulators are implemented as stand alone applications. In this paper we present enhancements to the TSCH-Sim network simulator in order to facilitate its integration with an optimization algorithm. The core enhancement is the definitions and implementation of a set of REST APIs for TSCH-Sim that allows a remote optimization algorithm to set the network configuration, routes, and 802.15.4e TSCH schedule of a sensor network. The significance of the REST API is demonstrated through the integration of a Differential Evolution based TSCH scheduling optimizer executing in MATLAB leveraging the TSCH-Sim simulator through the REST APIs in order to find a TSCH schedule that maximizes throughput. read more... read less...

Keywords: 802.15.4e TSCH, TSCH-Sim, REST-API, Co-simulation, DE Optimization, MATLAB Simulation

Combining the Internet of Things (IoT) and the Internet of Behavior (IoB) to create a robust educational environment

JUSPN, volume-18 , Issue 2 (2023), PP 61 - 68

Published: 02 Apr 2023

DOI: 10.5383/JUSPN.18.02.002

by Ossama H. Embarak from Higher Colleges of Technology Dept. of Computer Sciences, Fujairah, UAE

Abstract: The ongoing COVID-19 pandemic has accelerated the adoption of e-learning, remote learning, and hybrid models in education. These models have become essential in meeting the demands of smart cities and addressing the limitations of traditional distance learning. However, to truly achieve academic success, education must be adaptive and tailored to the individual needs of students. This study presents a novel concept for intelligent educational systems that integrate Explainable Artificial Intelligence (XAI) and Internet of Behavior (IoB) technologies. The integration of these technologies aims to revolutionize intelligent educational systems by providing a more personalized and effective learning experience. By collecting and analyzing student behavior data, the system can provide real-time feedback and adjust to meet the needs of each individual student. The results of this study demonstrate the significant impact of IoB technology on student performance. The integration of IoB led to a substantial increase in student response from 40% to 79%. These findings highlight the potential for IoB to enhance learner assistance and improve system modifications to better meet the expectations of students for increased performance. The proposed concept of integrating XAI and IoB technologies in intelligent educational systems can pave the way for a more personalized and effective learning experience in the future. read more... read less...

Keywords: Tailored education, Hybrid models, Smart cities, XAI (Explainable Artificial Intelligence), IoB (Internet of Behavior) Personalized education Adaptive learning

Predicting Cardiovascular Events with Machine Learning Models and Heart Rate Variability

JUSPN, volume-18 , Issue 2 (2023), PP 49 - 59

Published: 02 Apr 2023

DOI: 10.5383/JUSPN.18.02.001

by Mohammad Moshawrab, Mehdi Adda, Abdenour Bouzouane, Hussein Ibrahim, Ali Raad from Département de Mathématiques, Informatique et Génie, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, G5L 3A1, Québec, Canada, Département D’informatique et de Mathématique, Université du Québec à Chicoutimi, Chicoutimi, 555 boulevard de l’Université, Chicoutimi, QC G7H 2B1, Canada, Institut Technologique de Maintenance Industrielle, 175 Rue de la Vérendrye, Sept-Îles, G4R 5B7, Québec, Canada and Dean of the Faculty of Science and Arts, Islamic University of Lebanon, Wardaniyeh, Lebanon

Abstract: Artificial Intelligence (AI) is increasingly becoming a potential answer to many of science’s most challenging problems. In this context, healthcare is using this technology and its advancement to improve the quality of services provided, including cardiac healthcare services. According to studies, Cardiovascular Diseases (CVDs) are among the most common and deadly diseases in the world. However, Artificial Intelligence and its branches such as Machine Learning (ML) and Deep Learning (DL) offer tremendous potential to improve disease diagnosis and even predict its occurrence. In this study, eight Machine Learning and Deep Learning models are created and trained with "PhsyioNet Smart Health for Assessing the Risk of Events via ECG Database" to analyze the characteristics of Heart Rate Variability and predict the occurrence of heart disease and cerebrovascular events. The results support the use of Artificial Intelligence in cardiology, with five of the proposed models outperforming previous implementations. Specifically, Support Vector Machines, TabTransformers, Deep Neural Networks, AdaBoost, and XGBoost achieved accuracy rates of 91.80%, 90.38%, 90.19%, 89.50%, and 89.10%, respectively. Further performance metrics are presented throught the article such as precision, recall and others. read more... read less...

Keywords: Artificial Intelligence, Machine Learning, Deep Learning, Cardiovascular Diseases, Heart Rate Variability

Hybrid-MiGrror: An Extension to the Hybrid Live Migration to Support Mobility in Edge Computing

JUSPN, volume-18 , Issue 1 (2023), PP 39 - 48

Published: 22 Jan 2023

DOI: 10.5383/JUSPN.18.01.006

by Arshin Rezazadeh, Davood Abednezhad, Hanan Lutfiyya from Computer Science Department, Western University, London ON N6A 3K7 Canada, Information and Communications Technology, Khouzestan Oxin Steel Company, Ahvaz, Iran

Abstract: User-Equipments (UEs) capable of working with cloud computing have grown exponentially in recent years, leading to a significant increase in the amount of data production. Moreover, upcoming Internet-of-Things (IoT) applications such as virtual and augmented reality, video streaming, intelligent transportation, and healthcare will require low latency, communications, and processing. Edge computing is a revolutionary criterion in which dispersed edge nodes supply resources near end devices because of the limited resources available on UEs. Rather than transmitting massive amounts of data to the cloud, edge nodes could filter, analyze, and process the data they receive using local resources. Mobile Edge Computing (MEC), in particular, when user mobility is considered, has the potential to significantly reduce processing delays and network traffic between UEs and servers. This research demonstrated a novel technique for migration that minimizes delay and downtime by utilizing edge computing. Our proposed method syncs more frequently than the pre-copy method which is the most used migration method that synchronizes (sync) the source and destination only based on multiple rounds. When compared to established migration methodologies, our results indicate that our mechanism has less latency, downtime, migration time, and packet loss. These results allow delay-sensitive applications that require ultra-low latency to function smoothly during migration. read more... read less...

Keywords: delay (latency), mobile edge computing (MEC), downtime, hand-off (handover), live migration, fog computing

Key Issues/Challenges for Inland Water Transportation Network in India

SWES, volume-09 , Issue 2 (2017), PP 75 - 81

Published: 13 Nov 2017

by S. Praveen, J. Jegan from M.E (Construction Engineering & Management), Department of Civil Engineering, James College of Engineering & Technology, Nagercoil, Tamil Nadu, India, Professor & Head, Department of Civil Engineering, University College of Engineering Ramanathapuram, Tamil Nadu, India

Abstract: The authors explore transport and trade as two broad service sectors of inland water resources. An attempt is made to find out the key issues and challenges from this sector with the evolving understanding of Indian inland water transportation system. The paper explains the background of inland water transport sector in India along with the discussion of issues and challenges faced by the same. The authors state that co-operation and co-ordination between inter-state governments is a strategic element to expand the network of inland water transport system in India beyond state boundaries. Conclusively, the prospect of inland navigation looks promising, wherein issues on infrastructural gaps and institutional support are addressed suitably. read more... read less...

Keywords: Inland Water, Navigation, Transportation, National Waterways

Wastewater Treatment Analysis, Technology and Challenges in Sweden

SWES, volume-09 , Issue 2 (2017), PP 67 - 74

Published: 18 Oct 2017

by Otu, Ubong Etop from Department Of Marine Biology, Akwa Ibom State University P.M.B 1167, Uyo, Nigeria

Abstract: Wastewater treatment is an efficient technique that increases the reclamation and reuse of wastewater for other productive uses, thereby, reducing the demand for freshwater resources, conservation of aquatic habitat, and sustainable utilization of water resources. Concerns for wastewater in Sweden began in the 1930s with only mechanical treatment but efficiently implemented in the 1960s as a result of significant eutrophication observed in open waters such as the Baltic Sea. Although prevailing wastewater treatment is fairly efficient, there is need to upgrade and improve existing treatment facilities (constructed in the 1970s) to mitigate potentially degradation of hygienic conditions due to the estimated increase in Swedish population. Thus, this paper will critically analyse prevailing treatment of wastewater in Sweden, the technology used and possible challenges encountered in the process. Small scale treatment of wastewater particularly practiced for dwellings not connected to municipal treatment plant will be discussed including sludge management in Sweden. The report further presented the significant issues including regulations, challenges, health hazards and constraints associated with wastewater treatment and reclamation. In addition, background information relating to potential technology to meet future wastewater treatment in Sweden were highlighted because current wastewater treatment facilities were constructed in the 1970s to provide services to Swedish population at that time. read more... read less...

Keywords: Water, Wastewater treatment, Grey wastewater, Sludge Management

Soil and Water Conservation in Thika-Chania catchment, Kenya

SWES, volume-09 , Issue 2 (2017), PP 59 - 65

Published: 04 Sep 2017

by Gathagu John Ng’ang’a, Mainya Johnstone Isiah, Oduor Brian Omondi, Khaldoon A. Mourad from Pan African University Institute for water and Energy Sciences, Tlemcen, Algeria, Center for Middle Eastern Studies, Lund University, Lund, 22100

Abstract: Soil and water conservation measures are widely practiced in Kenya to tackle the degradation of the ecosystems and to improve land productivity. Local government and NGOs have developed programs and campaigns about soil and water conservation measures. The aim of this study is to assess the need for soil and water conservation measures in Thika- Chania catchment by conducting a household survey using QuickTap Survey software. A total of 200 respondents were successfully interviewed and results analyzed in SPSS program. GIS tools were also used to do a classification of slopes in the study area. Results indicate that more than 90% of the people in the catchment area are farmers. In the recent years, 50% of the respondents have noted a decline in the vegetation. During the rain seasons, the intensity of color in the local rivers due to sediments have been observed to increase by 75% of the respondent while 9% said there was no change. More than 70% of the respondents indicated that the water levels have been on the declining trend especially during the low flows. Terraces and grass strips were the common soil and water conservation measures although some of them were severely degraded. We concluded that there is an immediate need to implement soil and water conservation measures in the catchment to enhance and restore the optimum functioning of the ecosystems. Capacity building and frequent extension services are needed to increase awareness on the impacts of the respective conservation methods. Incentives programs need to be established to encourage more farmers to participate in conserving and protecting their lands from degradation. read more... read less...

Keywords: Baseline survey, soil and water conservation, capacity building, degradation.

Modelling Water Demand and Efficient Use in Mbagathi Sub-Catchment Using Weap

SWES, volume-09 , Issue 1 (2017), PP 49 - 57

Published: 03 Apr 2017

by J. Nyika, G.N. Karuku, and R. N. Onwonga from Department of Land Resource Management and Agricultural Technology, Faculty of Agriculture, University of Nairobi, P.O. Box 29053-00625, Nairobi, Kenya

Abstract: Water systems have complex component interactions necessitating development and evaluation of management amidst uncertainties of climate and constrained natural resources. Conceptual models such as WEAP when used are effective planning and management tools as they forecast future effects of resource use efficiency at sub-catchment level using existent hydrological and climate data thereby acting as corrective measure to poor resources management. This study aimed at using WEAP model to forecast demand and analyze scenarios on efficient water use in Mbagathi subcatchment. WEAP model schematic was set to develop current and reference scenarios. Parameters used to run WEAP model were a GIS map of the sub-catchment, climate data from Kenya Meteorological Department at Dagorretti Corner Station, hydrological and water demand data from WRMA databases. High population growth and prolonged drought were predicted to increase water demand while reuse though not practised, was found by the model to be the most effective approach to manage unmet demands as compared to reduced conveyance losses and increased reservoir capacity. The study concluded that water reuse through exploitation of wastewater could be a viable solution to Mbagathi sub-catchment's water problems. read more... read less...

Keywords: water problems, necessitating development, evaluation of management, climate and constrained natural resources