Search results for: heat generation

Authors: S. Silverstone, J. Phadungtin

Abstract:

Today-s Wi Fi generation utilize the latest technology in their daily lives. Instructors at National University, the second largest non profit private institution of higher learning in California, are incorporating these new tools to modify their Online class formats to better accommodate these new skills in their distance education delivery modes. The University provides accelerated learning in a one-course per month format both Onsite and Online. Since there has been such a significant increase in Online classes over the past three years, and it is expected to grow even more over the over the next five years, Instructors cannot afford to maintain the status quo and not take advantage of these new options. It is at the discretion of the instructors which accessory they use and how comfortable and familiar they are with the technology. This paper explores the effects and summarizes students- comments of some of these new technological options which have been recently provided in order to make students- online learning experience more exciting and meaningful.

Keywords: Asynchronous chats, synchronous learning, VoIP.

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Authors: Majid Tolouei-Rad, Anurag Dhull

Abstract:

This paper describes various stages of design and prototyping of a modular robot for use in various industrial applications. The major goal of current research has been to design and make different robotic joints at low cost capable of being assembled together in any given order for achieving various robot configurations. Five different types of joins were designed and manufactured where extensive research has been carried out on the design of each joint in order to achieve optimal strength, size, modularity, and price. This paper presents various stages of research and development undertaken to engineer these joints that include material selection, manufacturing, and strength analysis. The outcome of this research addresses the birth of a new generation of modular industrial robots with a wider range of applications and greater efficiency.

Keywords: Actuator, control system, configuration, robot.

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Authors: Tadashi Watanabe, Jinya Katsuyama, Akihiro Mano

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The estimation of leak flow rates through narrow cracks in structures is of importance for nuclear reactor safety, since the leak flow could be detected before occurrence of loss-of-coolant accidents. The two-phase critical leak flow rates are calculated using the system analysis code, and two representative non-homogeneous critical flow models, Henry-Fauske model and Ransom-Trapp model, are compared. The pressure decrease and vapor generation in the crack, and the leak flow rates are found to be larger for the Henry-Fauske model. It is shown that the leak flow rates are not affected by the structural temperature, but affected largely by the roughness of crack surface.

Keywords: Crack, critical flow, leak, roughness.

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Authors: M. Jamuna Rani, K. Ramanathan

Abstract:

A steam power plant is housed with various types of equipments like boiler, turbine, heat exchanger etc. These equipments are mainly connected with piping systems. Such a piping layout design depends mainly on stress analysis and flexibility. It will vary with respect to pipe geometrical properties, pressure, temperature, and supports. The present paper is to analyze the presence and effect of hangers and expansion joints in the piping layout/routing using CAESAR-II software. Main aim of piping stress analysis is to provide adequate flexibility for absorbing thermal expansion, code compliance for stresses and displacement incurred in piping system. The design is said to be safe if all these are in allowable range as per code. In this study, a sample problem is considered for analysis as per power piping ASME B31.1 code and the results thus obtained are compared.

Keywords: ASTM B31.1, hanger, expansion joint, CAESAR-II.

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Authors: Lu Wei, Yunhao Zhu, Ping Deng, Wentao Yu

Abstract:

Past literature on business incubators distinguished incubators based on their mission statements. However, more and more mission statements become a slogan rather than a reality. It is therefore more appropriate to identify business incubators based on their real activities, rather than the missions they declared. With a sample of technology business incubators (TBIs) in China, we try to investigate business incubators’ real activities by examining the incubation efficiency along the following five dimensions, i.e., survival of new ventures, technology transfer, local economic growth, job creation, and profit generation. Furthermore, we identified six types of business incubators. The results indicate that generally Chinese TBIs have a greater preference for acquiring profits over other dimensions. 

Keywords: Business incubators, mission statements, real activities, incubation efficiency, technology business incubators, China.

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Authors: J. Dutta, P. Pranith Kumar Reddy

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This research paper portrays a comparative analysis of thermomechanical behaviour of Shielded Metal Arc Welding (SMAW) and Gas Tungsten Arc Welding (GTAW) of low carbon steel of AISI 1020 grade butt joints. The thermal history has been obtained by experimental work. We have focused on temperature dependent cooling rate as depicted by Adam’s two-dimensional model. The effect of moving point heat source of SMAW and GTAW on mechanical properties has been judged by optical and scanning electron micrographs of different regions in weld joints. The microhardness study has been carried to visualize the joint strength due to formation of different phases.

Keywords: Shielded metal arc welding, gas tungsten arc welding, low carbon steel, microhardness study, thermal history, microscopic morphology.

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Authors: Ali Nourollah, Mohsen Movahedinejad

Abstract:

In this paper a new algorithm to generate random simple polygons from a given set of points in a two dimensional plane is designed. The proposed algorithm uses a genetic algorithm to generate polygons with few vertices. A new merge algorithm is presented which converts any two polygons into a simple polygon. This algorithm at first changes two polygons into a polygonal chain and then the polygonal chain is converted into a simple polygon. The process of converting a polygonal chain into a simple polygon is based on the removal of intersecting edges. The experiments results show that the proposed algorithm has the ability to generate a great number of different simple polygons and has better performance in comparison to celebrated algorithms such as space partitioning and steady growth.

Keywords: Divide and conquer, genetic algorithm, merge polygons, Random simple polygon generation.

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Authors: M. Ayazi, R. Karami, B. Kamkari

Abstract:

Solid oxide fuel cells have been considered in the last years as one of the most promising technologies for very highefficiency electric energy generation from hydrogen or other hydrocarbons, both with simple fuel cell plants and with integrated gas turbine-fuel cell systems. In the present study, a detailed thermodynamic analysis has been carried out. Mass and exergy balances are performed not only for the whole plant but also for each component in order to evaluate the thermal efficiency of combined cycle. Moreover, different sources of irreversibilities within the SOFC stack have been discussed and a parametric study conducted to evaluate the effect of temperature as well as pressure on SOFC irreversibilities and its performance. In this investigation methane and hydrogen have been used for fueling the SOFC stack and combustion chamber.

Keywords: SOFC, Energy, Power turbine, Irreversibility.

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Authors: Abir Yahya, Hacen Dhahri, Khalifa Slimi

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The present paper deals with a numerical simulation of temperature field inside a solid oxide fuel cell (SOFC) components. The temperature distribution is investigated using a co-flow planar SOFC comprising the air and fuel channel and two-ceramic electrodes, anode and cathode, separated by a dense ceramic electrolyte. The Lattice Boltzmann method (LBM) is used for the numerical simulation of the physical problem. The effects of inlet temperature, anode thermal conductivity and current density on temperature distribution are discussed. It was found that temperature distribution is very sensitive to the inlet temperature and the current density.

Keywords: Solid oxide fuel cell, Heat sources, temperature, Lattice Boltzmann method.

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Authors: Shwe Wut Hmon Aye, Kay Thi Lwin, Waing Waing Kay Khine Oo

Abstract:

As the material used for fuselage structure must possess low density, high strength to weight ratio, the selection of appropriate materials for fuselage structure is one of the most important tasks. Aluminum metal itself is soft and low in strength. It can be made stronger by giving proper combination of suitable alloy addition, mechanical treatment and thermal treatment. The usual thermal treatment given to aluminum alloys is called age-hardening or precipitation hardening. In this paper, the studies are carried out on 7075 aluminum alloy which is how to improve strength level for fuselage structure. The marked effect of the strength on the ternary alloy is clearly demonstrated at several ageing times and temperatures. It is concluded that aluminum-zinc-magnesium alloy can get the highest strength level in natural ageing.

Keywords: Aluminum alloy, ageing, heat treatment, strength.

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Authors: H. Ettouney, A. AL-Haddad, S. Saqer

Abstract:

This paper focuses on assessment of air pollution in Umm-Alhyman, Kuwait, which is located south to oil refineries, power station, oil field, and highways. The measurements were made over a period of four days in March and July in 2001, 2004, and 2008. The measured pollutants included methanated and nonmethanated hydrocarbons (MHC, NMHC), CO, CO2, SO2, NOX, O3, and PM10. Also, meteorological parameters were measured, which includes temperature, wind speed and direction, and solar radiation. Over the study period, data analysis showed increase in measured SO2, NOX and CO by factors of 1.2, 5.5 and 2, respectively. This is explained in terms of increase in industrial activities, motor vehicle density, and power generation. Predictions of the measured data were made by the ISC-AERMOD software package and by using the ISCST3 model option. Finally, comparison was made between measured data against international standards.

Keywords: Air pollution, Emission inventory, ISCST3 model, Modeling

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Authors: M. Si Abdallah, B. Zeghmati

Abstract:

A numerical analysis used to simulate the effects of wavy surfaces and thermal radiation on natural convection heat transfer boundary layer flow over an inclined wavy plate has been investigated. A simple coordinate transformation is employed to transform the complex wavy surface into a flat plate. The boundary layer equations and the boundary conditions are discretized by the finite difference scheme and solved numerically using the Gauss-Seidel algorithm with relaxation coefficient. Effects of the wavy geometry, the inclination angle of the wavy plate and the thermal radiation on the velocity profiles, temperature profiles and the local Nusselt number are presented and discussed in detail.

Keywords: Free convection, wavy surface, inclined surface, thermal radiation.

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Authors: To-Yuan Chen, Tzu-Ching Shih, Hao-Li Liu, Kuen-Cheng Ju

Abstract:

The focal spot of a high intensity focused ultrasound transducer is small. To heat a large target volume, multiple treatment spots are required. If the power of each treatment spot is fixed, it could results in insufficient heating of initial spots and over-heating of later ones, which is caused by the thermal diffusion. Hence, to produce a uniform heated volume, the delivered energy of each treatment spot should be properly adjusted. In this study, we proposed an iterative, extrapolation technique to adjust the required ultrasound energy of each treatment spot. Three different scanning pathways were used to evaluate the performance of this technique. Results indicate that by using the proposed technique, uniform heating volume could be obtained.

Keywords: focused ultrasound, thermal therapy, uniform heating, iteration, extrapolation, scan

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Authors: M. Izadi, S. Hossainpour, D. Jalali-Vahid

Abstract:

Nanofluids are novel fluids that are going to have an important role in future industrial thermal device designs. Studies are being predominantly conducted on the mechanism of these heat transfers. The key to this attraction is in the increase in thermal conductivity brought about by the Nanofluids compared with the base fluid. Different models have been proposed for calculation of effective thermal conduction that has been gradually modified. In this investigation effect of nanolayer structure and Brownian motion of particles are studied and a new modified thermal conductivity model is proposed. Temperature, concentration, nanolayer thickness and particle size are taken as variables and their effect are studied simultaneously on the thermal conductivity of the fluids, showing the concentration of the nanoparticles to affect the nanolayer thickness which also affects the Brownian motion.

Keywords: Relative thermal conductivity, Brownian motion, Nanolayer structure.

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Authors: Nitish Sharma, G. G. Karady

Abstract:

This paper presents a scheme for the protection of loop system from all type of faults using the direction of fault current. The presence of distributed generation in today’s system increases the complexity of fault detection as the power flow is bidirectional. Hence, protection scheme specific to this purpose needs to be developed. This paper shows a fast protection scheme using communication which can be fiber optic or wireless. In this paper, the possibility of wireless communication for protection is studied to exchange the information between the relays. The negative sequence and positive sequence directional elements are used to determine the direction of fault current. A PSCAD simulation is presented and validated using commercial SEL relays.

Keywords: Smart grid protection, pilot protection, power system simulation, wireless communication.

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Authors: Abir S. Al-Harrasi, Eyad B. Al-Zadjali, Zahran S. Al-Salti

Abstract:

Entrepreneurship has captured the attention of policy-makers, educators and researchers in the last few decades. It has been regarded as a main driver for economic growth, development and employment generation in many countries worldwide. However, scholars have not agreed on the key factors that impact entrepreneurial intention.  This study attempts, through an extensive literature review, to provide a holistic view and a more comprehensive understanding of the key factors that lead university undergraduate students to become entrepreneurs. A systematic literature review is conducted and several scientific articles and reports have been examined. The results of this study indicate that there are four main sets of factors: the personality-traits factors, contextual factors, motivational factors, and personal background factors. This research will serve as a base for future studies and will have valuable implications for policy makers and educators.

Keywords: Entrepreneurship, Entrepreneurial Intention.

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Authors: R. Ziaie Moayed, F. Allahyari

Abstract:

Soil stabilization has been widely used to improve soil strength and durability or to prevent erosion and dust generation. Generally to reduce problems of clayey soils in engineering work and to stabilize these soils additional materials are used. The most common materials are lime, fly ash and cement. Using this materials, although improve soil property , but in some cases due to financial problems and the need to use special equipment are limited .One of the best methods for stabilization clayey soils is neutralization the clay particles. For this purpose we can use ion exchange materials. Ion exchange solution like CBR plus can be used for soil stabilization. One of the most important things in using CBR plus is determination the amount of this solution for various soils with different properties. In this study a laboratory experiment is conduct to evaluate the ion exchange capacity of three soils with various plasticity index (PI) to determine amount or required CBR plus solution for soil stabilization.

Keywords: CBR plus, clayey soils, ion exchange, soil stabilization

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Authors: Supayotin Na Songkla, Winai Jaikla

Abstract:

This article presents a resistorless current-mode firstorder allpass filter based on second generation current controlled current conveyors (CCCIIs). The features of the circuit are that: the pole frequency can be electronically controlled via the input bias current: the circuit description is very simple, consisting of 2 CCCIIs and single grounded capacitor, without any external resistors and component matching requirements. Consequently, the proposed circuit is very appropriate to further develop into an integrated circuit. Low input and high output impedances of the proposed configuration enable the circuit to be cascaded in current-mode without additional current buffers. The PSpice simulation results are depicted. The given results agree well with the theoretical anticipation. The application example as a current-mode quadrature oscillator is included.

Keywords: First-order all pass filter, current-mode, CCCII.

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Authors: Navid Javidtash, Abdolmohamad Davodi, Mojtaba Hakimzadeh, Abdolreza Roozbeh

Abstract:

Economic dispatch (ED) is considered to be one of the key functions in electric power system operation. This paper presents a new hybrid approach based genetic algorithm (GA) to economic dispatch problems. GA is most commonly used optimizing algorithm predicated on principal of natural evolution. Utilization of chaotic queue with GA generates several neighborhoods of near optimal solutions to keep solution variation. It could avoid the search process from becoming pre-mature. For the objective of chaotic queue generation, utilization of tent equation as opposed to logistic equation results in improvement of iterative speed. The results of the proposed approach were compared in terms of fuel cost, with existing differential evolution and other methods in literature.

Keywords: Economic Dispatch(ED), Optimization, Fuel Cost, Genetic Algorithm (GA).

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Authors: Sara Soltanpour, Adolfo Foriero

Abstract:

Frost heave is arguably the most problematic adverse phenomenon in cold region areas. It is a complex process that depends on heat and water transfer. The coupled physical fields generate considerable heave stresses as well as deformations. In the present study, a coupled Thermal-Hydraulic-Mechanical (THM) model using COMSOL Multiphysics in frozen unsaturated soils, such as fine sand, is investigated. Particular attention to the frost heave and temperature distribution, as well as the water migrating during soil freezing, is assessed. The results obtained from the numerical simulations are consistent with the results measured in the full-scale tests conducted by Cold Regions Research and Engineering Laboratory (CRREL).

Keywords: Frost heave, numerical simulations, COMSOL software, unsaturated freezing soil.

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Authors: N. Ojaroudi Parchin, H. Jahanbakhsh Basherlou, Y. Al-Yasir, A. M. Abdulkhaleq, R. A. Abd-Alhameed, P. S. Excell

Abstract:

A compact design of multi-sector patch antenna array for 60 GHz applications is presented and discussed in details. The proposed design combines five 1x8 linear patch antenna arrays, referred to as sectors, in a multi-sector configuration. The coaxial-fed radiation elements of the multi-sector array are designed on 0.2 mm Rogers RT5880 dielectrics. The array operates in the frequency range of 58-62 GHz and provides switchable directional/omnidirectional radiation beams with high gain and high directivity characteristics. The designed multi-sector array exhibits good performances and could be used in the fifth generation (5G) cellular networks.

Keywords: MM-wave communications, multi-sector array, patch antenna, small cell networks.

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Authors: Ramin Khamedi, Isa Ahmadi

Abstract:

In this study acoustic emission (AE) signals obtained during deformation and fracture of two types of ferrite-martensite dual phase steels (DPS) specimens have been analyzed in frequency domain. For this reason two low carbon steels with various amounts of carbon were chosen, and intercritically heat treated. In the introduced method, identifying the mechanisms of failure in the various phases of DPS is done. For this aim, AE monitoring has been used during tensile test of several DPS with various volume fraction of the martensite (VM) and attempted to relate the AE signals and failure mechanisms in these steels. Different signals, which referred to 2-3 micro-mechanisms of failure due to amount of carbon and also VM have been seen. By Fast Fourier Transformation (FFT) of signals in distinct locations, an excellent relationship between peak frequencies in these areas and micro-mechanisms of failure were seen. The results were verified by microscopic observations (SEM).

Keywords: Dual Phase Steel, Deformation, Acoustic Emission.

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Authors: A. Morsli, A.Tlemçani, N. Ould Cherchali, M. S. Boucherit

Abstract:

This article presents two methods for the compensation of harmonics generated by a nonlinear load. The first is the classic method P-Q. The second is the controller by modern method of artificial intelligence specifically fuzzy logic. Both methods are applied to a shunt Active Power Filter (sAPF) based on a three-phase voltage converter at five levels NPC topology. In calculating the harmonic currents of reference, we use the algorithm P-Q and pulse generation, we use the intersective PWM. For flexibility and dynamics, we use fuzzy logic. The results give us clear that the rate of Harmonic Distortion issued by fuzzy logic is better than P-Q.

Keywords: Fuzzy logic controller, P-Q method, Pulse Width Modulation (PWM), shunt Active Power Filter (sAPF), Total Harmonic Distortion (THD).

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Authors: Yu Chen, Weiwei Ren, Xiaojing Mu, Feng Zhang, Yi Xu

Abstract:

The superhydrophobic surface is widely used to reduce friction for the flow inside micro-channel and can be used to control/manipulate fluid, cells and even proteins in lab-on-chip. Fabricating micro grooves on hydrophobic surfaces is a common method to obtain such superhydrophobic surface. This study utilized the numerical method to investigate the effect of eccentric micro-grooves on the friction of flow inside micro-channel. A detailed parametric study was conducted to reveal how the eccentricity of micro-grooves affects the micro-channel flow under different grooves sizes, channel heights, Reynolds number. The results showed that the superhydrophobic surface with eccentric micro-grooves induces less friction than the counter part with aligning micro-grooves, which means requiring less power for pumps.

Keywords: Superhydrophobic, transverse grooves, heat transfer, slip length, microfluidics.

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Authors: Ilya Kavalchuk, Hayrettin Arisoy, Alex Stojcevski, Aman Maun Than Oo

Abstract:

Electric vehicles are one of the most complicated electric devices to simulate due to the significant number of different processes involved in electrical structure of it. There are concurrent processes of energy consumption and generation with different onboard systems, which make simulation tasks more complicated to perform. More accurate simulation on energy consumption can provide a better understanding of all energy management for electric transport. As a result of all those processes, electric transport can allow for a more sustainable future and become more convenient in relation to the distance range and recharging time. This paper discusses the problems of energy consumption simulations for electric vehicles using different software packages to provide ideas on how to make this process more precise, which can help engineers create better energy management strategies for electric vehicles.

Keywords: Electric Vehicles, EV, Power Consumption, Power Management, Simulation.

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Authors: Nicolas Zufferey

Abstract:

Ant algorithms are well-known metaheuristics which have been widely used since two decades. In most of the literature, an ant is a constructive heuristic able to build a solution from scratch. However, other types of ant algorithms have recently emerged: the discussion is thus not limited by the common framework of the constructive ant algorithms. Generally, at each generation of an ant algorithm, each ant builds a solution step by step by adding an element to it. Each choice is based on the greedy force (also called the visibility, the short term profit or the heuristic information) and the trail system (central memory which collects historical information of the search process). Usually, all the ants of the population have the same characteristics and behaviors. In contrast in this paper, a new type of ant metaheuristic is proposed, namely SMART (for Solution Methods with Ants Running by Types). It relies on the use of different population of ants, where each population has its own personality.

Keywords: Optimization, Metaheuristics, Ant Algorithms, Evolutionary Procedures, Population-Based Methods.

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Authors: Beste Kaysı, Yasemin Topaloğlu

Abstract:

Usability is one of the most important quality attributes for web-based information systems. Specifically, for e-commerce applications, usability becomes more prominent. In this study, we aimed to explore the features that experienced users seek in e-commerce applications. We used eye tracking method in evaluations. Eye movement data are obtained from the eye-tracking method and analyzed based on task completion time, number of fixations, as well as heat map and gaze plot measures. The results of the analysis show that the eye movements of participants' are too static in certain areas and their areas of interest are scattered in many different places. It has been determined that this causes users to fail to complete their transactions. According to the findings, we outlined the issues to improve the usability of e-commerce websites. Then we propose solutions to identify the issues. In this way, it is expected that e-commerce sites will be developed which will make experienced users more satisfied.

Keywords: E-commerce websites, eye tracking method, usability, website evaluations.

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Authors: H. Fazlinejad, A. Halvaee

Abstract:

In this study, characteristics of ATIG welds using ZnO flux on aluminum was investigated and compared with TIG welds. Autogenously AC-ATIG bead on plate welding was applied on Al1050 plate with a coating of ZnO as the flux. Different levels of welding current and flux layer thickness was considered to study the effect of heat input and flux quantity on ATIG welds and was compared with those of TIG welds. Geometrical investigation of the weld cross sections revealed that penetration depth of the ATIG welds with ZnO flux, was increased up to 2 times in some samples compared to the TIG welds. Optical metallographic and Scanning Electron Microscopy (SEM) observations revealed similar microstructures in TIG and ATIG welds. Composition of the ATIG welds slag was also analyzed using X-ray diffraction. In both TIG and ATIG samples, the lowest values of microhardness were observed in the HAZ.

Keywords: ATIG, active flux, weld penetration, Al 1050, ZnO.

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Authors: Sara Felloni, Giuliano Strini

Abstract:

We explore entanglement in composite quantum systems and how its peculiar properties are exploited in quantum information and communication protocols by means of Diagrams of States, a novel method to graphically represent and analyze how quantum information is elaborated during computations performed by quantum circuits. We present quantum diagrams of states for Bell states generation, measurements and projections, for dense coding and quantum teleportation, for probabilistic quantum machines designed to perform approximate quantum cloning and universal NOT and, finally, for quantum privacy amplification based on entanglement purification. Diagrams of states prove to be a useful approach to analyze quantum computations, by offering an intuitive graphic representation of the processing of quantum information. They also help in conceiving novel quantum computations, from describing the desired information processing to deriving the final implementation by quantum gate arrays.

Keywords: Diagrams of states, entanglement, quantum circuits, quantum information.

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Authors: P. O. Angienda, D. J. Hill

Abstract:

The purpose of this study was to elucidate the factors affecting antimicrobial effectiveness of essential oils against food spoilage and pathogenic bacteria. The minimum inhibition concentrations (MIC) of the essential oils, were determined by turbidimetric technique using Biocreen C, analyzer. The effects of pH ranging from 7.3 to 5.5 in absence and presence of essential oils and/or NaCl on the lag time and mean generation time of the bacteria at 370C, were carried out and results were determined showed that, combination of low pH and essential oil at 370C had additive effects against the test micro-organisms. The combination of 1.2 % (w/v) of NaCl and clove essential oil at 0.0325% (v/v) was effective against E. coli. The use of concentrations less than MIC in combination with low pH and or NaCl has the potential of being used as an alternative to “traditional food preservatives".

Keywords: Antimicrobial, Bacteria, Bioscreen C, essential oil.

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