Search results for: time multiplier setting

Authors: H. Shokouhmand, M. Tajerian

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At this paper velocity profile modeling and heat transfer in the micro heat pipes by using electrohydrodynamic (EHD) field at the transient regime have been studied. In the transient flow, one dimensional and two phase fluid flow and heat transfer for micro heat pipes with square cross section, have been studied. At this model Coulomb and dielectrophoretic forces are considered. Coupled, non-linear equations governed on the model (continuity, momentum, and energy equations) have been solved simultaneously by numerical methods. Transient behavior of affecting parameters e.g. substrate temperature, velocity of coolant liquid, radius of curvature and coolant liquid pressure, has been verified. By obtaining and plotting the mentioned parameters, it has been shown that the EHD field enhances the heat transfer process. So, the time required to reach the steady state regime decreases from 16 seconds to 2.4 seconds after applying EHD field. Another result has been observed implicitly that by increasing the heat input the effect of EHD field became more significant. The numerical results of model predict the experimental results available in the literature successfully, and it has been observed there is a good agreement between them.

Keywords: micro heat pipe, transient modeling, electrohydrodynamics, capillary, meniscus

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Authors: M. Y. Ismail, M. Inam

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This paper presents the design and analysis of Liquid Crystal (LC) based tunable reflectarray antenna with slot embedded patch element configurations within X-band frequency range. The slots are shown to modify the surface current distribution on the patch element of reflectarray which causes the resonant patch element to provide different resonant frequencies depending on the slot dimensions. The simulated results are supported and verified by waveguide scattering parameter measurements of different reflectarray unit cells. Different rectangular slots on patch element have been fabricated and a change in resonant frequency from 10.46GHz to 8.78GHz has been demonstrated as the width of the rectangular slot is varied from 0.2W to 0.6W. The rectangular slot in the center of the patch element has also been utilized for the frequency tunable reflectarray antenna design based on K-15 Nematic LC. For the active reflectarray antenna design, a frequency tunability of 1.2% from 10GHz to 9.88GHz has been demonstrated with a dynamic phase range of 103° provided by the measured scattering parameter results. Time consumed by liquid crystals for reconfiguration, which is one of the drawback of LC based design, has also been disused in this paper.

Keywords: liquid crystal, tunable reflectarray, frequency tunability, dynamic phase range

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Authors: Mohammad Rahim Rahimi, Yuji Hoshino, Kota Masuyama, Naoya Nakajima

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The aim of this paper is to study the behavior or influence of climate adaptation and change in Kabul Metropolitan Area (KMA). The Kabul Metropolitan Area (KMA) in Afghanistan includes Kabul existing city and Kabul New City (KNC). Kabul Metropolitan Area has admitted the challenges due to climate change, which includes, natural climate change, social transformations, city landscape, economic and political issues, etc. KMA will withhold a large population within its boundaries. The main problems competed in KMA were the temperature changes over the years, especially in Hindukush and Central Highland of Afghanistan from 1950 up to 2010, 1°C and 1.71°C raised respectively and reduction of water table in existing Kabul city due to the use of more water from underground water resources. Moreover, the cause of temperature rise, the precipitation in spring season and melting of snow early or melting in compressed time as well as the water source is directly related to the capacity of the mountains snow and precipitation. In addition, the temperature increased, and precipitation declined in spring period. It is directly related to separation of dissertation, migration to the cities and other challenges that we will discuss in this paper.

Keywords: climate change, climate adaption, adaptation in Kabul metropolitan area, precipitation

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Authors: Behbood Maashkar

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One of the principles for societies’ development is the requirement to consider past experiences. Man should always take advantage of the predecessor’s experiences and analyze their works and methods. The predecessors have had a more friendly relationship with nature and their lives less damaged the nature, and it is one of the elements of green building. One of the things the ancients have observed in regard to green building in their houses, stores, sacred places, etc. was using wind-catchers as an air conditioning and cooling system which can be considered as the first foundations of green building. In designing houses Iranian architects have paid a great attention to the factor of making use of more shaded area in hot season and insulation of wall and ceiling against influence of hot weather and also air circulation inside the building. In order to circulate the air inside closed spaces and decrease the temperature, they have considered different winds which blow in Iran and its effective power, and in order to make use of it they invented wind catcher. Direction of wind blow and its height from the earth as well as the time and duration of wind blow and other factors have been effective in making different types of wind catchers. Using wind catchers has been and is prevalent mainly in central and south regions of Iran, coastal areas of Persian Gulf, and Khorasan, especially in cities like Yazd, Kashan, Bam, Abarghoo, Jahrom, and Tabas.

Keywords: environment pollution, green building, Iran, wind catchers

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Authors: K. Durairaj, I. N. Umar

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Lately, asynchronous discussion forum is integrated in higher educational institutions as it may increase learning process, learners’ understanding, achievement and knowledge construction. Asynchronous discussion forum is used to complement the traditional, face-to-face learning session in hybrid learning courses. However, studies have proven that students’ engagement in online forum are still unconvincing. Thus, the aim of this study is to investigate the motivating factors and obstacles that affect the learners’ engagement in asynchronous discussion forum. This study is carried out in one of the public higher educational institutions in Malaysia with 18 postgraduate students as samples. The authors have developed a 40-items questionnaire based on literature review. The results indicate several factors that have encouraged or limited students’ engagement in asynchronous discussion forum: (a) the practices or behaviors of peers, or instructors, (b) the needs for the discussions, (c) the learners’ personalities, (d) constraints in continuing the discussion forum, (e) lack of ideas, (f) the level of thoughts, (g) the level of knowledge construction, (h) technical problems, (i) time constraints and (j) misunderstanding. This study suggests some recommendations to increase the students’ engagement in online forums. Finally, based upon the findings, some implications are proposed for further research.

Keywords: asynchronous discussion forum, engagement, factors, motivating, limiting

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Authors: Benu Gupta

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The purpose of the study was to assess the impact of yogic exercise on cardiovascular exercises on selected college students of high altitude. The research was conducted on college students of high altitude in Shimla for their cardiovascular function [Blood Pressure (BP), VO2 Max (TLC) and Pulse Rate (PR)] in respect to yogic exercise. Total 139 students were randomly selected from Himachal University colleges in Shimla. The study was conducted in three phases. The subjects were identified in the first phase of research program then further in next phase they were physiologically tested, and yogic exercise battery was operated in different time frame. The entire subjects were treated with three months yogic exercise. The entire lot of students were again evaluated physiologically [(Cardiovascular measurement: Blood Pressure (BP), VO2 Max (TLC) and Pulse Rate (PR)] with standard equipments. The statistical analyses of the variance (PR, BP (SBP & DBP) and TLC) were done. The result reveals that there was a significant difference in TLC; whereas there was no significant difference in PR. For BP statistical analysis suggests no significant difference were formed. Result showed that the BP of the participants were more inclined towards normal standard BP i.e. 120-80 mmHg.

Keywords: cardiovascular function, college students, high altitude, yogic exercise

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Authors: Rania Khadim, Mohammed Erritali, Abdelhakim Maaden

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Nowadays Wireless Sensor Networks have attracted worldwide research and industrial interest, because they can be applied in various areas. Geographic routing protocols are very suitable to those networks because they use location information when they need to route packets. Obviously, location information is maintained by Location-Based Services provided by network nodes in a distributed way. In this paper we choose to evaluate the performance of two hierarchical rendezvous location based-services, GLS (Grid Location Service) and HLS (Hierarchical Location Service) coupled to the GPSR routing protocol (Greedy Perimeter Stateless Routing) for Wireless Sensor Network. The simulations were performed using NS2 simulator to evaluate the performance and power of the two services in term of location overhead, the request travel time (RTT) and the query Success ratio (QSR). This work presents also a new scalability performance study of both GLS and HLS, specifically, what happens if the number of nodes N increases. The study will focus on three qualitative metrics: The location maintenance cost, the location query cost and the storage cost.

Keywords: location based-services, routing protocols, scalability, wireless sensor networks

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Authors: P. Jayashree, S. Rajkumar

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With social networks and smart devices generating a multitude of data, effective data management is the need of the hour for networks and cloud applications. Some applications need effective storage while some other applications need effective communication over networks and data reduction comes as a handy solution to meet out both requirements. Most of the data compression techniques are based on data statistics and may result in either lossy or lossless data reductions. Though lossy reductions produce better compression ratios compared to lossless methods, many applications require data accuracy and miniature details to be preserved. A variety of data compression algorithms does exist in the literature for different forms of data like text, image, and multimedia data. In the proposed work, a generic progressive compression algorithm, based on probabilistic encoding, called PEINS is projected as an enhancement over irrational number stored coding technique to cater to storage issues of increasing data volumes as a cost effective solution, which also offers data security as a secondary outcome to some extent. The proposed work reveals cost effectiveness in terms of better compression ratio with no deterioration in compression time.

Keywords: compression ratio, generic compression, irrational number storage, probabilistic encoding

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Authors: Rhadinia Tayag-Relanes, Felina C. Young

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This study was conducted to analyze the noodle production process at Yan Hu Food Manufacturing for the basis of production improvement. The study utilized the PDCA approach and record review in the gathering of data for the calendar year 2019 from August to October data of the noodle products miki, canton, and misua. Causal-comparative research was used in this study; it attempts to establish cause-effect relationships among the variables such as descriptive statistics and correlation, both were used to compute the data gathered. The study found that miki, canton, and misua production has different cycle time sets for each production and has different production outputs in every set of its production process and a different number of wastages. The company has not yet established its allowable rejection rate/ wastage; instead, this paper used a 1% wastage limit. The researcher recommended the following: machines used for each process of the noodle product must be consistently maintained and monitored; an assessment of all the production operators by checking their performance statistically based on the output and the machine performance; a root cause analysis for finding the solution must be conducted; and an improvement on the recording system of the input and output of the production process of noodle product should be established to eliminate the poor recording of data.

Keywords: continuous improvement, process, operations, PDCA

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Authors: Saba Belgheisi

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Food packaging, is an important discipline in the area of food technology, concerns preservation and protection of foods. The objective of this research was to determine of the effect of whey protein based edible coating on the moisture loss and sensory attributes of fresh mutton after 0, 1, 3 and 5 days at 5° C. The moisture content, moisture loss and sensory attributes (juiciness, color and odor) of the coated and uncoated samples were analyzed. The results showed that, moisture content, moisture loss, juiciness and color of the coated and uncoated samples have significant differences (p < 0.05) at the intervals of 0 to 1 and 1 to 3 days of storage. But no significant difference was observed at interval time 3 to 5 days of storage (p > 0.05). Also, there was no significant differences in the odor values of the coated and uncoated samples (p > 0.05). Therefore, the coated samples had consistently more moisture, juiciness and colored values than uncoated samples after 3 days at 5° C. So, whey protein edible coating could enhance product presentation and eliminate the need for placing absorbent pads at the bottom of the trays.

Keywords: coating, whey protein, mutton, moisture, sensory

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Authors: Fathi Ali Swaid

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The CBR test is widely used in the assessment of granular materials in base, subbase and subgrade layers of road and airfield pavements. Despite the success of this method, but it depends on a limited numbers of soil samples. This limitation do not adequately account for the spatial variability of soil properties. Thus, assessment is derived using these cursory soil data are likely to contain errors and thus make interpretation and soil characterization difficult. On the other hand quantitative methods of soil inventory at the field scale involve the design and adoption of sampling regimes and laboratory analysis that are time consuming and costly. In the latter case new technologies are required to efficiently sample and observe the soil in the field. This is particularly the case where soil bearing capacity is prevalent, and detailed quantitative information for determining its cause is required. In this paper, an electrical resistivity method DC is described and its application in Elg'deem Dirt road, located in Gasser Ahmad - Misurata, Libya. Results from the DC instrument were found to be correlated with the CBR values (r2 = 0.89). Finally, it is noticed that, the correlation can be used with experience for determining CBR value using basic soil electrical resistivity measurements and checked by few CBR test representing a similar range of CBR.

Keywords: California bearing ratio, basic soil electrical resistivity, CBR, soil, subgrade, new technologies

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Authors: Yuya Tanigami, Naoaki Yamanaka, Satoru Okamoto

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Economic losses due to delays in traffic congestion regarding urban transportation networks have become a more serious social problem as traffic volume increases. Platooning has recently been attracting attention from many researchers to alleviate traffic jams, especially on the highway. On highways, platooning can have positive effects, such as reducing inter-vehicular distance and reducing air resistance. However, the impacts of platooning on urban roads have not been addressed in detail since traffic lights may break the platoons. In this study, we propose a platooning method using L2 norm and cosine similarity to form a platoon with highly similar routes. Also, we investigate the sorting method within a platoon according to each vehicle’s straightness. Our proposed sorting platoon method, which uses two lanes, eliminates Head of Line Blocking at the intersection and improves throughput at intersections. This paper proposes a cyber-physical system (CPS) approach to collaborative urban platoon control. We conduct simulations using the traffic simulator SUMO and the road network, which imitates Manhattan Island. Results from the SUMO confirmed that our method shortens the average travel time by 10-20%. This paper shows the validity of forming a platoon based on destination vectors and sorting vehicles within a platoon.

Keywords: CPS, platooning, connected car, vector correlation

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Authors: N. C. Sarkar, A. Bhaskar, Z. Zheng

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The driving behavior in area-based (i.e., non-lane based) traffic is induced by the presence of other individuals in the choice space from the driver’s visual perception area. The driving behavior of a subject vehicle is constrained by the potential leaders and leaders are frequently changed over time. This paper is to determine a stochastic model for a parameter of modified intelligent driver model (MIDM) in area-based traffic (as in developing countries). The parametric and non-parametric distributions are presented to fit the parameters of MIDM. The goodness of fit for each parameter is measured in two different ways such as graphically and statistically. The quantile-quantile (Q-Q) plot is used for a graphical representation of a theoretical distribution to model a parameter and the Kolmogorov-Smirnov (K-S) test is used for a statistical measure of fitness for a parameter with a theoretical distribution. The distributions are performed on a set of estimated parameters of MIDM. The parameters are estimated on the real vehicle trajectory data from India. The fitness of each parameter with a stochastic model is well represented. The results support the applicability of the proposed modeling for parameters of MIDM in area-based traffic flow simulation.

Keywords: area-based traffic, car-following model, micro-simulation, stochastic modeling

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Authors: Ali A. Hammadi

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In this work, a practical study on a commissioned Giga Passive Optical Network (GPON) fiber to the home access network in Kuwait is presented. The work covers the framework of the conceptual design of the deployed Passive Optical Networks (PONs), access network, optical fiber cable network distribution, technologies, and standards. The work also describes methodologies applied by system engineers for design of Optical Network Terminals (ONTs) and Optical Line Terminals (OLTs) transceivers with respect to the distance, operating wavelengths, splitting ratios. The results have demonstrated and justified the limitation of transmission distance of a PON link in Fiber to The Premises (FTTP) to not exceed 20 km. Optical Time Domain Reflector (OTDR) test has been carried for this project to confirm compliance with International Telecommunication Union (ITU) specifications regarding the total length of the deployed optical cable, total loss in dB, and loss per km in dB/km with respect to the operating wavelengths. OTDR test results with traces for segments of implemented fiber network will be provided and discussed.

Keywords: passive optical networks (PONs), fiber to the premises (FTTx), access network, OTDR

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Authors: Hidayatul Fitri, Petr Šařec

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The use of organic fertilizer is increasing nowadays, and the application must be conducted accurately to provide the right benefits for plants and maintain soil health. Improper application of fertilizers can cause problems for both plants and the environment. This study investigated the liquid organic fertilizer application, particularly digestate, varied into different application doses concerning mitigation of adverse environmental impacts, improving water infiltration ability, and crop yields. The experiment was established into eight variants with different digestate doses, conducted on emission monitoring and soil physical properties. As a result, the digestate application with shallow injection (5 cm in depth) was confirmed as an appropriate technique for applying liquid fertilizer into the soil. Gas emissions resulted in low concentration and declined gradually over time, obviously proved from the experiment conducted under two measurements immediately after application and the next day. Applied various doses of liquid digestate fertilizer affected the emission concentrations of NH3 volatilization, differing significantly and decreasing about 40% from the first to second measurement. In this study, winter wheat crop production significantly increases under digestate application with additional N fertilizer. This study suggested the long-term application of digestate to obtain more alteration of soil properties such as bulk density, penetration resistance, and hydraulic conductivity.

Keywords: liquid organic fertilizer, digestate, application, ammonia, emission

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Authors: O. Mowla, E. Kennedy, M. Stockenhuber

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Finding alternative renewable resources of energy has attracted the attentions in consequence of limitation of the traditional fossil fuel resources, increasing of crude oil price and environmental concern over greenhouse gas emissions. Biodiesel (or Fatty Acid Methyl Esters (FAME)), an alternative energy source, is synthesised from renewable sources such as vegetable oils and animal fats and can be produced from waste oils. FAME can be produced via hydroesterification of oils. The process involves two stages. In the first stage of this process, fatty acids and glycerol are being obtained by hydrolysis of the feed stock oil. In the second stage, the recovered fatty acids are then esterified with an alcohol to methyl esters. The presence of a catalyst accelerates the rate of the hydroesterification reaction of oils. The overarching aim of this study is to find the effect of using zeolite as a catalyst in the heterogeneous hydroesterification of soybean oil. Both stages of the catalytic hydroesterification of soybean oil had been conducted at atmospheric and high-pressure conditions using reflux glass reactor and Parr reactor, respectively. The effect of operating parameters such as temperature and reaction time on the overall yield of biodiesel formation was also investigated.

Keywords: biodiesel, heterogeneous catalytic hydroesterification, soybean oil, zeolite

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Authors: Wei Yongxiang, Zhu Haoyue, Tang Heng, Yuan Qunwei

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In order to study the preparation method of gear fatigue load spectrum for loaders, the load signal of four typical working conditions of loader is collected. The signal that reflects the law of load change is obtained by preprocessing the original signal. The torque of the drive axle is calculated by using the rain flow counting method. According to the operating time ratio of each working condition, the two-dimensional load spectrum based on the real working conditions of the drive axle of loader is established by the cycle extrapolation and synthesis method. The two-dimensional load spectrum is converted into one-dimensional load spectrum by means of the mean of torque equal damage method. Torque amplification includes the maximum load torque of the main reduction gear. Based on the theory of equal damage, the accelerated cycles are calculated. In this way, the load spectrum of the loading condition of the drive axle is prepared to reflect loading condition of the loader. The load spectrum can provide reference for fatigue life test and life prediction of loader drive axle.

Keywords: load spectrum, axle, torque, rain-flow counting method, extrapolation

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Authors: Salahaeddine Sbai

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Air quality analysis using machine learning models is a method employed to assess and predict air pollution levels. This approach leverages the capabilities of machine learning algorithms to analyze vast amounts of air quality data and extract valuable insights. By training these models on historical air quality data, they can learn patterns and relationships between various factors such as weather conditions, pollutant emissions, and geographical features. The trained models can then be used to predict air quality levels in real-time or forecast future pollution levels. This application of machine learning in air quality analysis enables policymakers, environmental agencies, and the general public to make informed decisions regarding health, environmental impact, and mitigation strategies. By understanding the factors influencing air quality, interventions can be implemented to reduce pollution levels, mitigate health risks, and enhance overall air quality management. Climate change is having significant impacts on Morocco, affecting various aspects of the country's environment, economy, and society. In this study, we use some machine learning models under python environment to predict and analysis air quality change over North of Morocco to evaluate the climate change impact on agriculture.

Keywords: air quality, machine learning models, pollution, pollutant emissions

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Authors: G. Tamilpavai, C. Vishnuppriya

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Studying DNA (deoxyribonucleic acid) sequence is useful in biological processes and it is applied in the fields such as diagnostic and forensic research. DNA is the hereditary information in human and almost all other organisms. It is passed to their generations. Earlier stage detection of defective DNA sequence may lead to many developments in the field of Bioinformatics. Nowadays various tedious techniques are used to identify defective DNA. The proposed work is to analyze and identify the cancer-causing DNA motif in a given sequence. Initially the human DNA sequence is separated as k-mers using k-mer separation rule. The separated k-mers are clustered using Self Organizing Map (SOM). Using Levenshtein distance measure, cancer associated DNA motif is identified from the k-mer clusters. Experimental results of this work indicate the presence or absence of cancer causing DNA motif. If the cancer associated DNA motif is found in DNA, it is declared as the cancer disease causing DNA sequence. Otherwise the input human DNA is declared as normal sequence. Finally, elapsed time is calculated for finding the presence of cancer causing DNA motif using clustering formation. It is compared with normal process of finding cancer causing DNA motif. Locating cancer associated motif is easier in cluster formation process than the other one. The proposed work will be an initiative aid for finding genetic disease related research.

Keywords: bioinformatics, cancer motif, DNA, k-mers, Levenshtein distance, SOM

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Authors: Angel Fabian Mijangos, Jaime Alvarez Quintana

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Key concepts like waste heat recycling or waste heat recovery are the basic ideas in thermoelectricity so as to the design the newest solid state sources of energy for a stable supply of electricity and environmental protection. According to several theoretical predictions; at device level, the geometry and configuration of the thermoelectric legs are crucial in the thermoelectric performance of the thermoelectric modules. Thus, in this work, it has studied the geometry effect of legs on the thermoelectric figure of merit ZT of the device. First, asymmetrical legs are proposed in order to reduce the overall thermal conductance of the device so as to increase the temperature gradient in the legs, as well as by harnessing the Thomson effect, which is generally neglected in conventional symmetrical thermoelectric legs. It has been developed a novel design of a thermoelectric module having asymmetrical legs, and by first time it has been validated experimentally its thermoelectric performance by realizing a proof-of-concept device which shows to have almost twofold the thermoelectric figure of merit as compared to conventional one. Moreover, it has been also varied the length of thermoelectric legs in order to analyze its effect on the thermoelectric performance of the device. Along with this, it has studied the impact of contact resistance in these systems. Experimental results show that device architecture can improve up to twofold the thermoelectric performance of the device.

Keywords: asymmetrical legs, heat recovery, heat recycling, thermoelectric module, Thompson effect

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Authors: Hadia Abdel Aziz, Raghda El Ebrashi

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Business models are shaped by their design space or the environment they are designed to be implemented in. The rapidly changing economic, technological, political, regulatory and market external environment severely affects business logic. This is particularly true for social enterprises whose core mission is to transform their environments, and thus, their whole business logic revolves around the interchange between the enterprise and the environment. The context in which social business operates imposes different business design constraints while at the same time, open up new design opportunities. It is also affected to a great extent by the impact that successful enterprises generate; a continuous loop of interaction that needs to be managed through a dynamic capability in order to generate a lasting powerful impact. This conceptual research synthesizes and analyzes literature on social enterprise, social enterprise business models, business model innovation, business model design, and the open system view theory to propose a new business model design process for social enterprises that takes into account the critical role of environmental factors. This process would help the social enterprise develop a dynamic capability that ensures the alignment of its business model to its environmental context, thus, maximizing its probability of success.

Keywords: social enterprise, business model, business model design, business model environment

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Authors: Ayoub Alsarhan, Ahmed Otoom, Yousef Kilani, Abdel-Rahman al-GHuwairi

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Wireless mesh networks (WMNs) have emerged recently to improve internet access and other networking services. WMNs provide network access to the clients and other networking functions such as routing, and packet forwarding. Spectrum scarcity is the main challenge that limits the performance of WMNs. Cognitive radio is proposed to solve spectrum scarcity problem. In this paper, we consider a cognitive wireless mesh network where unlicensed users (secondary users, SUs) can access free spectrum that is allocated to spectrum owners (primary users, PUs). Although considerable research has been conducted on spectrum allocation, spectrum assignment is still considered an important challenging problem. This problem can be solved using cognitive radio technology that allows SUs to intelligently locate free bands and access them without interfering with PUs. Our scheme considers several heuristics for spectrum allocation. These heuristics include: channel error rate, PUs activities, channel capacity and channel switching time. Performance evaluation of the proposed scheme shows that the scheme is able to allocate the unused spectrum for SUs efficiently.

Keywords: cognitive radio, dynamic spectrum access, spectrum management, spectrum sharing, wireless mesh networks

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Authors: Xian-Peng Jiang, Catherine C. Baucom, Toby Jiang, Robert L. Elliott

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HLA-G binds to the inhibitory receptors of uterine NK cells and plays an important role in protection of fetal cells from maternal NK lysis. HLA-G also mediates tumor escape, but the immunosuppressive role is often neglected. These studies have focused on the examination of HLA-G expression in human breast carcinoma and HLA-G immunosuppressive role in NK cytolysis. We examined HLA-G expression in breast cell lines by real time PCR, ELISA and immunofluorescent staining. We treated the breast cancer cell lines with anti-human HLA-G antibody or progesterone. Then, NK cytolysis was measured by using MTT assay. We find that breast carcinoma cell lines increase the expression of HLA-G mRNA and protein, compared to normal cells. Blocking HLA-G of the breast cancer cells by the antibody increases NK cytolysis. Progesterone upregulates HLA-G mRNA and protein of human breast cancer cell lines. The increased HLA-G expression suppresses NK cytolysis. In summary, human breast carcinoma overexpress HLA-G immunosuppressive molecules. Blocking HLA-G protein by antibody improves NK cytolysis. In contrast, upregulation of HLA-G expression by progesterone impairs NK cytolytic function. Thus, HLA-G is a new immunosuppressive checkpoint and potential cancer immunotherapeutic target.

Keywords: HLA-G, Breast carcinoma, NK cells, Immunosuppressive checkpoint

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Authors: Thomas Bryan, Veton Kepuska, Ivica Kostanic

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A simple adaptive voice activity detector (VAD) is implemented using Gabor and gammatone atomic decomposition of speech for high Gaussian noise environments. Matching pursuit is used for atomic decomposition, and is shown to achieve optimal speech detection capability at high data compression rates for low signal to noise ratios. The most active dictionary elements found by matching pursuit are used for the signal reconstruction so that the algorithm adapts to the individual speakers dominant time-frequency characteristics. Speech has a high peak to average ratio enabling matching pursuit greedy heuristic of highest inner products to isolate high energy speech components in high noise environments. Gabor and gammatone atoms are both investigated with identical logarithmically spaced center frequencies, and similar bandwidths. The algorithm performs equally well for both Gabor and gammatone atoms with no significant statistical differences. The algorithm achieves 70% accuracy at a 0 dB SNR, 90% accuracy at a 5 dB SNR and 98% accuracy at a 20dB SNR using 30dB SNR as a reference for voice activity.

Keywords: atomic decomposition, gabor, gammatone, matching pursuit, voice activity detection

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Authors: Mohit Kalra, Varun S., Mayuri Gandhi

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CeF3 nanophosphors has been extensively investigated in the recent years for lighting and numerous bio-applications. Down conversion emissions in CeF3:Eu3+/Tb3+ phosphors were studied with the aim of obtaining a white light emitting composition, by a simple co-precipitation method. The material was characterized by X-ray Diffraction (XRD), High Resolution Transmission Electron Microscopy (HR-TEM), Fourier Transform Infrared Spectroscopy (FT-IR) and Photoluminescence (PL). Uniformly distributed nanoparticles were obtained with an average particle size 8-10 nm. Different doping concentrations were performed and fluorescence study was carried out to optimize the dopants concentration for maximum luminescence intensity. The steady state and time resolved luminescence studies confirmed efficient energy transfer from the host to activator ions. Different concentrations of Tb 3+, Eu 3+ were doped to achieve a white light emitting phosphor for UV-based Light Emitting Diodes (LEDs). The nanoparticles showed characteristic emission of respective dopants (Eu 3+, Tb3+) when excited at the 4f→5d transition of Ce3+. The chromaticity coordinates for these samples were calculated and the CeF3 doped with Eu 3+ and Tb3+ gave an emission very close to white light. These materials may find its applications in optoelectronics and various bio applications.

Keywords: white light down-conversion, nanophosphors, LEDs, rare earth, cerium fluoride, lanthanides

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Authors: Areti Okalidou, Paul D. Hatzigiannakoglou, Aikaterini Vatou, George Kyriafinis

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Young children are nowadays adept at using technology. Hence, computer-based auditory training programs (CBATPs) have become increasingly popular in aural rehabilitation for children with hearing loss and/or with cochlear implants (CI). Yet, their clinical utility for prognostic, diagnostic, and monitoring purposes has not been explored. The purposes of the study were: a) to develop an updated version of the auditory rehabilitation tool for Greek-speaking children with cochlear implants, b) to develop a database for behavioral responses, and c) to compare accuracy rates and reaction times in children differing in hearing status and other medical and demographic characteristics, in order to assess the tool’s clinical utility in prognosis, diagnosis, and progress monitoring. The updated version of the auditory rehabilitation tool was developed on a tablet, retaining the User-Centered Design approach and the elements of the Virtual Reality (VR) serious game. The visual stimuli were farm animals acting in simple game scenarios designed to trigger children’s responses to animal sounds, names, and relevant sentences. Based on an extended version of Erber’s auditory development model, the VR game consisted of six stages, i.e., sound detection, sound discrimination, word discrimination, identification, comprehension of words in a carrier phrase, and comprehension of sentences. A familiarization stage (learning) was set prior to the game. Children’s tactile responses were recorded as correct, false, or impulsive, following a child-dependent set up of a valid delay time after stimulus offset for valid responses. Reaction times were also recorded, and the database was in Εxcel format. The tablet version of the auditory rehabilitation tool was piloted in 22 preschool children with Νormal Ηearing (ΝΗ), which led to improvements. The study took place in clinical settings or at children’s homes. Fifteen children with CI, aged 5;7-12;3 years with post-implantation 0;11-5;1 years used the auditory rehabilitation tool. Eight children with CI were monolingual, two were bilingual and five had additional disabilities. The control groups consisted of 13 children with ΝΗ, aged 2;6-9;11 years. A comparison of both accuracy rates, as percent correct, and reaction times (in sec) was made at each stage, across hearing status, age, and also, within the CI group, based on presence of additional disability and bilingualism. Both monolingual Greek-speaking children with CI with no additional disabilities and hearing peers showed high accuracy rates at all stages, with performances falling above the 3rd quartile. However, children with normal hearing scored higher than the children with CI, especially in the detection and word discrimination tasks. The reaction time differences between the two groups decreased in language-based tasks. Results for children with CI with additional disability or bilingualism varied. Finally, older children scored higher than younger ones in both groups (CI, NH), but larger differences occurred in children with CI. The interactions between familiarization of the software, age, hearing status and demographic characteristics are discussed. Overall, the VR game is a promising tool for tracking the development of auditory skills, as it provides multi-level longitudinal empirical data. Acknowledgment: This work is part of a project that has received funding from the Research Committee of the University of Macedonia under the Basic Research 2020-21 funding programme.

Keywords: VR serious games, auditory rehabilitation, auditory training, children with cochlear implants

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Authors: Mohammad Mohammadzadeh, Alireza Ghasempour

Abstract:

In this paper, a new design of monopole antenna has been proposed that increases the contrast of intravascular magnetic resonance images through increasing the homogeneity of the intrinsic signal-to-noise ratio (ISNR) distribution around the antenna. The antenna is made of a coaxial cable with three parasitic elements. Lengths and positions of the elements are optimized by the improved genetic algorithm (IGA) for 1.5, 3, 4.7, and 7Tesla MRI systems based on a defined cost function. Simulations were also conducted to verify the performance of the designed antenna. Our simulation results show that each time IGA is executed different values for the parasitic elements are obtained so that the cost functions of those antennas are high. According to the obtained results, IGA can also find the best values for the parasitic elements (regarding cost function) in the next executions. Additionally, two dimensional and one-dimensional maps of ISNR were drawn for the proposed antenna and compared to the previously published monopole antenna with one parasitic element at the frequency of 64MHz inside a saline phantom. Results verified that in spite of ISNR decreasing, there is a considerable improvement in the homogeneity of ISNR distribution of the proposed antenna so that their multiplication increases.

Keywords: intravascular MR antenna, monopole antenna, parasitic elements, signal-to-noise ratio (SNR), genetic algorithm

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Authors: Mohammad Obeidat, Ayman Mansour

Abstract:

In this paper a unique issue rising from feedback control of Atrial Fibrillation monitoring system with embedded communication channels has been investigated. One of the important factors to measure the performance of the feedback control closed loop system is disturbance and noise attenuation factor. It is important that the feedback system can attenuate such disturbances on the atrial fibrillation heart rate signals. Communication channels depend on network traffic conditions and deliver different throughput, implying that the sampling intervals may change. Since signal estimation is updated on the arrival of new data, its dynamics actually change with the sampling interval. Consequently, interaction among sampling, signal estimation, and the controller will introduce new issues in remotely controlled Atrial Fibrillation system. This paper treats a remotely controlled atrial fibrillation system with one communication channel which connects between the heart rate and rhythm measurements to the remote controller. Typical and optimal signal estimation schemes is represented by a signal averaging filter with its time constant derived from the step size of the signal estimation algorithm.

Keywords: atrial fibrillation, communication channels, closed loop, estimation

Procedia PDF Downloads 378

Authors: Mustafa Tufekci, Caner Guven

Abstract:

In Automotive Industry, sliding door systems that are also used as body closures, are safety members. Extreme product tests are realized to prevent failures in a design process, but these tests realized experimentally result in high costs. Finite element analysis is an effective tool used for the design process. These analyses are used before production of a prototype for validation of design according to customer requirement. In result of this, the substantial amount of time and cost is saved. Finite element model is created for geometries that are designed in 3D CAD programs. Different element types as bar, shell and solid, can be used for creating mesh model. The cheaper model can be created by the selection of element type, but combination of element type that was used in model, number and geometry of element and degrees of freedom affects the analysis result. Sliding door system is a good example which used these methods for this study. Structural analysis was realized for sliding door mechanism by using FE models. As well, physical tests that have same boundary conditions with FE models were realized. Comparison study for these element types, were done regarding test and analyses results then the optimum combination was achieved.

Keywords: finite element analysis, sliding door mechanism, element type, structural analysis

Procedia PDF Downloads 329

Authors: Akbar Rahmani Nejad, Pejman Rahmani Nejad, Ahmad Rahmani Nejad

Abstract:

we proposed the arresting of atmospheric lightning and passing the electrical current of lightning-bolts through underground water tanks to produce Hydrogen and restoring Hydrogen in reservoirs to be used later as clean and sustainable energy. It is proposed to implement this method for storage of extra electrical power (instead of lightning energy) during low energy demand periods to produce hydrogen as a clean energy source to store in big reservoirs and later generate electricity by burning the stored hydrogen at an appropriate time. This method prevents the complicated process of changing the output power of nuclear power plants. It is possible to pass an electric current through sodium chloride solution to produce chlorine and sodium or human waste to produce Methane, etc. however atmospheric lightning is an accidental phenomenon, but using this free energy just by connecting the output of lightning arresters to the output of power plant during low energy demand period which there is no significant change in the design of power plant or have no cost, can be considered completely an economical design

Keywords: hydrogen gas, lightning energy, power plant, resistive element

Procedia PDF Downloads 141