Search results for: Operating temperature

Authors: M. Zerikat, M. Bendjebbar, N. Benouzza

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In this paper, a novel approach for robust trajectory tracking of induction motor drive is presented. By combining variable structure systems theory with fuzzy logic concept and neural network techniques, a new algorithm is developed. Fuzzy logic was used for the adaptation of the learning algorithm to improve the robustness of learning and operating of the neural network. The developed control algorithm is robust to parameter variations and external influences. It also assures precise trajectory tracking with the prescribed dynamics. The algorithm was verified by simulation and the results obtained demonstrate the effectiveness of the designed controller of induction motor drives which considered as highly non linear dynamic complex systems and variable characteristics over the operating conditions.

Keywords: Induction motor, fuzzy-logic control, neural network control, indirect field oriented control.

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Authors: Y. A. Chan, H. J. Liu, K. C. Tseng, T. C. Kuo

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Green propellants used for satellite-level propulsion system become attractive in recent years because the non-toxicity and lower requirements of safety protection. One of the green propellants, high-concentration hydrogen peroxide H2O2 solution (≥70% w/w, weight concentration percentage), often known as high-test peroxide (HTP), is considered because it is ITAR-free, easy to manufacture and the operating temperature is lower than traditional monopropellant propulsion. To establish satellite propulsion technology, the National Space Organization (NSPO) in Taiwan has initialized a long-term cooperation project with the National Cheng Kung University to develop compatible tank and thruster. An experimental propulsion payload has been allocated for the future self-reliant satellite to perform orbit transfer and maintenance operations. In the present research, an 1-Newton thruster prototype is designed and the thrusting force is measured by a pendulum-type platform. The preliminary hot-firing test at ambient environment showed the generated thrust and the specific impulse are about 0.7 Newton and 102 seconds, respectively.

Keywords: Hydrogen peroxide, propulsion, RCS, satellite.

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Authors: H. Junoh, K. Palanisamy, C. H. Yip, F. L. Pua

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This study investigates the influence of low temperature thermo-chemical pretreatment of organic food waste on performance of COD solubilisation. Both temperature and alkaline agent were reported to have effect on solubilizing any possible biomass including organic food waste. The three independent variables considered in this pretreatment were temperature (50-90oC), pretreatment time (30-120 minutes) and alkaline concentration, sodium hydroxide, NaOH (0.7-15 g/L). The maximal condition obtained were 90oC, 15 g/L NaOH for 2 hours. Solubilisation has potential in enhancing methane production by providing high amount of soluble components at early stage during anaerobic digestion.

Keywords: Food waste, pretreatments, respond surface methodology, ANOVA, anaerobic digestion.

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Authors: A. Yönetken, A. Erol, M. Cakmakkaya

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Intermetallic materials are among advanced technology materials that have outstanding mechanical and physical properties for high temperature applications. Especially creep resistance, low density and high hardness properties stand out in such intermetallics. The microstructure, mechanical properties of %88Ni- %10Cr and %2Mn powders were investigated using specimens produced by tube furnace sintering at 900-1300°C temperature. A composite consisting of ternary additions, a metallic phase, Fe, Cr and Mn have been prepared under Ar shroud and then tube furnace sintered. XRD, SEM (Scanning Electron Microscope), were investigated to characterize the properties of the specimens. Experimental results carried out for composition %88Ni-%10Cr and %2Mn at 1300°C suggest that the best properties as 138,80HV and 6,269/cm3 density were obtained at 1300°C.

Keywords: Composite, Intermetallic, High temperature, Sintering.

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Authors: Wenyu Song, Bingxi Li, Zhongbin Fu, Baocheng Jiang

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Full - Scale Accelerated Loading System, one part of “the Eleventh - Five - Year National Grand Technology Infrastructure Program" is a facility to evaluate the performance and service life of different kinds of pavements subjected to traffic loading under full - controlled environment. While simulating the environments of frigid zone and permafrost zone, the accurate control of air temperature, road temperature and roadbed temperature are the key points and also aporias for the designment. In this paper, numerical simulations are used to determine the design parameters of the frozen soil simulation system. At first, a brief introduction of the Full - Scale Accelerate Loading System was given. Then, the temperature control method of frozen soil simulation system was proposed. Finally, by using finite element simulations, the optimal design of frozen soil simulation system was obtained. This proposed design, which was obtained by finite element simulations, provided significant referents to the ultimate design of the environment simulation system.

Keywords: China, finite element simulation, frozen soilsimulation system, preliminary design.

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Authors: Amir Gandomkar, Tahereh Soltani Gord faramarzi, Parisa Safaripour Chafi, Abdol-Reza Amani

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Temperature, humidity and precipitation in an area, are parameters proved influential in the climate of that area, and one should recognize them so that he can determine the climate of that area. Climate changes are of primary importance in climatology, and in recent years, have been of great concern to researchers and even politicians and organizations, for they can play an important role in social, political and economic activities. Even though the real cause of climate changes or their stability is not yet fully recognized, they are a matter of concern to researchers and their importance for countries has prompted them to investigate climate changes in different levels, especially in regional, national and continental level. This issue has less been investigated in our country. However, in recent years, there have been some researches and conferences on climate changes. This study is also in line with such researches and tries to investigate and analyze the trends of climate changes (temperature and precipitation) in Sefid-roud (the name of a river) basin. Three parameters of mean annual precipitation, temperature, and maximum and minimum temperatures in 36 synoptic and climatology stations in a statistical period of 49 years (1956-2005) in the stations of Sefid-roud basin were analyzed by Mann-Kendall test. The results obtained by data analysis show that climate changes are short term and have a trend. The analysis of mean temperature revealed that changes have a significantly rising trend, besides the precipitation has a significantly falling trend.

Keywords: Trend, Climate changes, Sefid-roud, Mann-Kendall

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Authors: Arash Karimipour, M. Afrand, M. M. Bazofti

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The periodic mixed convection of a water-copper nanofluid inside a rectangular cavity with aspect ratio of 3 is investigated numerically. The temperature of the bottom wall of the cavity is assumed greater than the temperature of the top lid which oscillates horizontally with the velocity defined as u = u0 sin (ω t). The effects of Richardson number, Ri, and volume fraction of nanoparticles on the flow and thermal behavior of the nanofluid are investigated. Velocity and temperature profiles, streamlines and isotherms are presented. It is observed that when Ri < 1, heat transfer rate is much greater than when Ri > 1. The higher value of Ri corresponds to a lower value of the amplitude of the oscillation of Num in the steady periodic state. Moreover, increasing the volume fraction of the nanoparticles increases the heat transfer rate.

Keywords: Nanofluid, Top lid oscillation, Mixed convection, Volume fraction

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Authors: Natarajan. E, Ganapathy Sundaram. E

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Fixed-bed slow pyrolysis experiments of rice husk have been conducted to determine the effect of pyrolysis temperature, heating rate, particle size and reactor length on the pyrolysis product yields. Pyrolysis experiments were performed at pyrolysis temperature between 400 and 600°C with a constant heating rate of 60°C/min and particle sizes of 0.60-1.18 mm. The optimum process conditions for maximum liquid yield from the rice husk pyrolysis in a fixed bed reactor were also identified. The highest liquid yield was obtained at a pyrolysis temperature of 500°C, particle size of 1.18-1.80 mm, with a heating rate of 60°C/min in a 300 mm length reactor. The obtained yield of, liquid, gas and solid were found be in the range of 22.57-31.78 %, 27.75-42.26 % and 34.17-42.52 % (all weight basics) respectively at different pyrolysis conditions. The results indicate that the effects of pyrolysis temperature and particle size on the pyrolysis yield are more significant than that of heating rate and reactor length. The functional groups and chemical compositions present in the liquid obtained at optimum conditions were identified by Fourier Transform-Infrared (FT-IR) spectroscopy and Gas Chromatography/ Mass Spectroscopy (GC/MS) analysis respectively.

Keywords: Slow pyrolysis, Rice husk, Recycling, Biomass.

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Authors: T.C.Manjunath, Ph.D., Ashok Kusagur, Shruthi Sanjay, Saritha Sindushree, C. Ardil

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This paper deals with the design, development & implementation of a temperature sensor using zigbee. The main aim of the work undertaken in this paper is to sense the temperature and to display the result on the LCD using the zigbee technology. ZigBee operates in the industrial, scientific and medical (ISM) radio bands; 868 MHz in Europe, 915 MHz in the USA and 2.4 GHz in most jurisdictions worldwide. The technology is intended to be simpler and cheaper than other WPANs such as Bluetooth. The most capable ZigBee node type is said to require only about 10 % of the software of a typical Bluetooth or Wireless Internet node, while the simplest nodes are about 2 %. However, actual code sizes are much higher, more like 50 % of the Bluetooth code size. ZigBee chip vendors have announced 128-kilobyte devices. In this work undertaken in the design & development of the temperature sensor, it senses the temperature and after amplification is then fed to the micro controller, this is then connected to the zigbee module, which transmits the data and at the other end the zigbee reads the data and displays on to the LCD. The software developed is highly accurate and works at a very high speed. The method developed shows the effectiveness of the scheme employed.

Keywords: Zigbee, Microcontroller, PIC, Transmitter, Receiver, Synchronous, Blue tooth, Communication.

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Authors: Anna Romanova, Morteza A. Alani

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Corrosion of concrete sewer pipes induced by sulfuric acid is an acknowledged problem and a ticking time-bomb to sewer operators. Whilst the chemical reaction of the corrosion process is well-understood, the indirect roles of other parameters in the corrosion process which are found in sewer environment are not highly reflected on. This paper reports on a field studies undertaken in Austria and United Kingdom, where the parameters of temperature, pH, H2S and CO2 were monitored over a period of time. The study establishes that (i) effluent temperature and pH have similar daily pattern and peak times, when examined in minutes scale; (ii) H2S and CO2 have an identical hourly pattern; (iii) H2S instant or shifted relation to effluent temperature is governed by the root mean square value of CO2.

Keywords: Concrete corrosion, carbon dioxide, hydrogen sulphide, sewer pipe, sulfuric acid.

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Authors: Tao Tao, Wang Jing, Cao Zhisong, Liu Yi, Qie Dianfu

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The precision of heat flux simulation influences the temperature field and test aberration for TB test and also reflects the test level for spacecraft development. This paper describes TB tests for a small satellite using solar simulator, electric heaters, calrod heaters to evaluate the difference of the three methods. Under the same boundary condition, calrod heaters cases were about 6oC higher than solar simulator cases and electric heaters cases for non-external-heat-flux cases (extreme low temperature cases). While calrod heaters cases and electric heaters cases were 5~7oC and 2~3oC lower than solar simulator cases respectively for high temperature cases. The results show that the solar simulator is better than calrod heaters for its better collimation, non-homogeneity and stability.

Keywords: solar simulation, infrared simulation, TB test, TMM

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Authors: Anushree, Chhaya Sharma, Satish Kumar

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Catalytic wet air oxidation (CWAO) is normally carried out at elevated temperature and pressure. This work investigates the potential of NiO-CeO₂ nano-catalyst in CWAO of paper industry wastewater under milder operating conditions of 90 °C and 1 atm. The NiO-CeO₂ nano-catalysts were synthesized by a simple co-precipitation method and characterized by X-ray diffraction (XRD), before and after use, in order to study any crystallographic change during experiment. The extent of metal-leaching from the catalyst was determined using the inductively coupled plasma optical emission spectrometry (ICP-OES). The catalytic activity of nano-catalysts was studied in terms of total organic carbon (TOC), adsorbable organic halides (AOX) and chlorophenolics (CHPs) removal. Interestingly, mixed oxide catalysts exhibited higher activity than the corresponding single-metal oxides. The maximum removal efficiency was achieved with Ce₄₀Ni₆₀ catalyst. The results indicate that the CWAO process is efficient in removing the priority organic pollutants from wastewater, as it exhibited up to 59% TOC, 55% AOX, and 54 % CHPs removal.

Keywords: Nano-materials, NiO-CeO2, wastewater, wet air oxidation.

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Authors: Ayudhia P. Gusti, Semin

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It is known that total operating cost of a vessel is dominated by the cost of fuel consumption. How to reduce the fuel cost of ship so that the operational costs of fuel can be minimized is the question that arises. As the basis of these kinds of problem, sailing speed determination is an important factor to be considered by a shipping company. Optimal speed determination will give a significant influence on the route and berth schedule of ships, which also affect vessel operating costs. The purpose of this paper is to clarify some important issues about ship speed optimization. Sailing speed, displacement, sailing time, and specific fuel consumption were obtained from shipping log data to be further analyzed for modeling the speed optimization. The presented speed optimization model is expected to affect the fuel consumption and to reduce the cost of fuel consumption.

Keywords: Maritime transportation, reducing fuel, shipping log data, speed optimization.

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Authors: Amar Al-Obaidi, Verena Kräusel, Dirk Landgrebe

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Induction assisted single point incremental forming (IASPIF) is a flexible method and can be simply utilized to form a high strength alloys. Due to the interaction between the mechanical and thermal properties during IASPIF an evaluation for the process is necessary to be performed analytically. Therefore, a numerical simulation was carried out in this paper. The numerical analysis was operated at both room and elevated temperatures then compared with experimental results. Fully coupled dynamic temperature displacement explicit analysis was used to simulated the hot single point incremental forming. The numerical analysis was indicating that during hot single point incremental forming were a combination between complicated compression, tension and shear stresses. As a result, the equivalent plastic strain was increased excessively by rising both the formed part depth and the heating temperature during forming. Whereas, the forming forces were decreased from 5 kN at room temperature to 0.95 kN at elevated temperature. The simulation shows that the maximum true strain was occurred in the stretching zone which was the same as in experiment.

Keywords: Induction heating, single point incremental forming, FE modeling, advanced high strength steel.

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Authors: A. N. Jannah, R. Abd-Shukor, H. Abdullah

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The effect of nano Co3O4 addition on the superconducting properties of (Bi, Pb)-2223 system was studied. The samples were prepared by the acetate coprecipitation method. The Co3O4 with different sizes (10-30 nm and 30-50 nm) from x=0.00 to 0.05 was added to Bi1.6Pb0.4Sr2Ca2Cu3Oy(Co3O4)x. Phase analysis by XRD method, microstructural examination by SEM and dc electrical resistivity by four point probe method were done to characterize the samples. The X-ray diffraction patterns of all the samples indicated the majority Bi-2223 phase along with minor Bi-2212 and Bi-2201 phases. The volume fraction was estimated from the intensities of Bi- 2223, Bi-2212 and Bi-2201 phase. The sample with x=0.01 wt% of the added Co3O4 (10-30 nm size) showed the highest volume fraction of Bi-2223 phase (72%) and the highest superconducting transition temperature, Tc (~102 K). The non-added sample showed the highest Tc(~103 K) compared to added samples with nano Co3O4 (30-50 nm size) added samples. Both the onset critical temperature Tc(onset) and zero electrical resistivity temperature Tc(R=0) were in the range of 103-115 ±1K and 91-103 ±1K respectively for samples with added Co3O4 (10-30 nm and 30-50 nm).

Keywords: Bi(Pb)-Sr-Ca-Cu-O superconductor, coprecipitation, nano Co3O4, transition temperature TC.

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Authors: Ali Ghiaseddin , Akram Nemati

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In a pilot plant scale of a fluidized bed reactor, a reduction reaction of sodium sulfate by natural gas has been investigated. Natural gas is applied in this study as a reductant. Feed density, feed mass flow rate, natural gas and air flow rate (independent parameters)and temperature of bed and CO concentration in inlet and outlet of reactor (dependent parameters) were monitored and recorded at steady state. The residence time was adjusted close to value of traditional reaction [1]. An artificial neural network (ANN) was established to study dependency of yield and carbon gradient on operating parameters. Resultant 97% accuracy of applied ANN is a good prove that natural gas can be used as a reducing agent. Predicted ANN model for relation between other sources carbon gradient (accuracy 74%) indicates there is not a meaningful relation between other sources carbon variation and reduction process which means carbon in granule does not have significant effect on the reaction yield.

Keywords: reduction by natural gas, fluidized bed, sulfate, sulfide, artificial neural network

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Authors: A. Vilutis, V. Jankauskas

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The paper presents the results of the investigation of the dry sliding friction of wood-plastic composites (WPCs) against tungsten carbide-cobalt (WC-Co) hard alloy. The dependence of the dynamic coefficient of friction on the main influencing factors (vertical load, temperature, and sliding distance) was investigated by evaluating their mutual interaction. Multiple regression analysis showed a high polynomial dependence (adjusted R2 > 0.98). The resistance of the composite to thermo-mechanical effects determines how temperature and force factors affect the magnitude of the coefficient of friction. WPC-B composite has the lowest friction and highest resistance compared to WPC-A, while composite and cemented carbide materials wear the least. Energy Dispersive Spectroscopy (EDS), based on elemental composition, provided important insights into the friction process.

Keywords: Friction, composite, carbide, temperature.

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Authors: Eka PW, T. Okazaki, Y. Murakami, N., Hozumi, M. Nagao

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The breakdown strength characteristic of Low Density Polyethylene films (LDPE) under DC voltage application and the effect of water absorption have been studied. Mainly, our experiment was investigated under two conditions; dry and heavy water absorption. Under DC ramp voltage, the result found that the breakdown strength under heavy water absorption has a lower value than dry condition. In order to clarify the effect, the temperature rise of film was observed using non contact thermograph until the occurrence of the electrical breakdown and the conduction current of the sample was also measured in correlation with the thermograph measurement. From the observations, it was shown that under the heavy water absorption, the hot spot in the samples appeared at lower voltage. At the same voltage the temperature of the hot spot and conduction current was higher than that under the dry condition. The measurement result has a good correlation between the existence of a critical field for conduction current and thermograph observation. In case of the heavy water absorption, the occurrence of the threshold field was earlier than the dry condition as result lead to higher of conduction current and the temperature rise appears after threshold field was significantly increased in increasing of field. The higher temperature rise was caused by the higher current conduction as the result the insulation leads to breakdown to the lower field application.

Keywords: Low density polyethylene, heavy water absorption, conduction current, temperature rise.

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Authors: Thach D. Do, Juhum Kwon, Chang-Joo Moon

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A Ground Control System (GCS), which controls Unmanned Aerial Vehicles (UAVs) and monitors their missionrelated data, is one of the major components of UAVs. In fact, some traditional GCSs were built on an expensive, complicated hardware infrastructure with workstations and PCs. In contrast, a GCS on a portable device – such as an Android phone or tablet – takes advantage of its light-weight hardware and the rich User Interface supported by the Android Operating System. We implemented that kind of GCS and called it Ground System Software (GSS) in this paper. In operation, our GSS communicates with UAVs or other GSS via TCP/IP connection to get mission-related data, visualizes it on the device-s screen, and saves the data in its own database. Our study showed that this kind of system will become a potential instrument in UAV-related systems and this kind of topic will appear in many research studies in the near future.

Keywords: Android Operating System, Ground Control System, Mobile Device, Unmanned Aerial Vehicle.

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Authors: P. Prakasam, M. Madheswaran

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A generalized Digital Modulation Identification algorithm for adaptive demodulator has been developed and presented in this paper. The algorithm developed is verified using wavelet Transform and histogram computation to identify QPSK and QAM with GMSK and M–ary FSK modulations. It has been found that the histogram peaks simplifies the procedure for identification. The simulated results show that the correct modulation identification is possible to a lower bound of 5 dB and 12 dB for GMSK and QPSK respectively. When SNR is above 5 dB the throughput of the proposed algorithm is more than 97.8%. The receiver operating characteristics (ROC) has been computed to measure the performance of the proposed algorithm and the analysis shows that the probability of detection (Pd) drops rapidly when SNR is 5 dB and probability of false alarm (Pf) is smaller than 0.3. The performance of the proposed algorithm has been compared with existing methods and found it will identify all digital modulation schemes with low SNR.

Keywords: Bit Error rate, Receiver Operating Characteristics, Software Defined Radio, Wavelet Transform.

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Authors: O. Alizadeh Sahraei, A. Khodadadi, Y. Mortazavi, M. Vesali Naseh, S. Mosadegh

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A composite made of plasma functionalized multiwall carbon nanotubes (MWNTs) coated with SnO2 was synthesized by sonochemical precipitation method. Thick layer of this nanocomposite material was used as ethanol sensor at low temperatures. The composite sensitivity for ethanol has increased by a factor of 2 at room temperature and by a factor of 13 at 250°C in comparison to that of pure SnO2. SEM image of nanocomposite material showed MWNTs were embedded in SnO2 matrix and also a higher surface area was observed in the presence of functionalized MWNTs. Greatly improved sensitivity of the composite material to ethanol can be attributed to new gas accessing passes through MWNTs and higher specific surface area.

Keywords: Carbon nanotube, Functionalized, Gas sensor, Low temperature, Nanocomposite, Tin oxide.

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Authors: J. Hey, D. A. Howey, R. Martinez-Botas, M. Lamperth

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This paper presents the development of a hybrid thermal model for the EVO Electric AFM 140 Axial Flux Permanent Magnet (AFPM) machine as used in hybrid and electric vehicles. The adopted approach is based on a hybrid lumped parameter and finite difference method. The proposed method divides each motor component into regular elements which are connected together in a thermal resistance network representing all the physical connections in all three dimensions. The element shape and size are chosen according to the component geometry to ensure consistency. The fluid domain is lumped into one region with averaged heat transfer parameters connecting it to the solid domain. Some model parameters are obtained from Computation Fluid Dynamic (CFD) simulation and empirical data. The hybrid thermal model is described by a set of coupled linear first order differential equations which is discretised and solved iteratively to obtain the temperature profile. The computation involved is low and thus the model is suitable for transient temperature predictions. The maximum error in temperature prediction is 3.4% and the mean error is consistently lower than the mean error due to uncertainty in measurements. The details of the model development, temperature predictions and suggestions for design improvements are presented in this paper.

Keywords: Electric vehicle, hybrid thermal model, transient temperature prediction, Axial Flux Permanent Magnet machine.

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Authors: Amirali Ebrahimi, T. A. G. Langrish

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The effect of various humidities on process yields and degrees of crystallinity for spray-dried powders from spray drying of lactose with humid air in a straight-through system have been studied. It has been suggested by Williams–Landel–Ferry kinetics (WLF) that a higher particle temperature and lower glass-transition temperature would increase the crystallization rate of the particles during the spray-drying process. Freshly humidified air produced by a Buchi-B290 spray dryer as a humidifier attached to the main spray dryer decreased the particle glass-transition temperature (Tg), while allowing the particle temperature (Tp) to reach higher values by using an insulated drying chamber. Differential scanning calorimetry (DSC) and moisture sorption analysis were used to measure the degree of crystallinity for the spray-dried lactose powders. The results showed that higher Tp-Tg, as a result of applying humid air, improved the process yield from 21 ± 4 to 26 ± 2% and crystallinity of the particles by decreasing the latent heat of crystallization from 43 ± 1 to 30 ± 11 J/g and the sorption peak height from 7.3 ± 0.7% to 6 ± 0.7%.

Keywords: Lactose, crystallization, spray drying, humid air.

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Authors: M. A. U. Baradi, F. B. Bulao, N. D. Ganotisi, M. Jose C. Regalado, F. P. Bongat, S. B. Manglinong, M. L. O. Quigao, N. G. T. Martinez, R. G. Ancheta, M. P. Ortal

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The effects of varying air temperature (full, ¾ full, ½ full aircon adjustment, no aircon) in polishing component of Single-Pass Mill on the quality of Philippine inbred rice variety, was investigated. Parameters measured were milling recovery (MR), headrice recovery (HR), and percentage with bran streaks. Cooling method (with aircon) increased MR, HR, and percentage with bran streaks of milled rice. Highest MR and HR (67.62%; 47.33%) were obtained from ¾ full adjustment whereas no aircon were lowest (66.27%; 39.76%). Temperature in polishing component at ¾ full adjustment was 33^oC whereas no aircon was 45^oC. There was increase of 1.35% in MR and 7.57% in HR. Additional cost of milling per kg due to aircon cooling was P0.04 at 300 tons/yr volume, with 0.15 yr payback period. Net income was estimated at ₱98,100.00. Percentage of kernels with bran streaks increased from 5%–14%, indicating more nutrients of milled rice.

Keywords: Aircon, air temperature, polishing component, quality, Single-Pass Mill.

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Authors: Shiyun Liu

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Radiant heating systems work fundamentally differently from air systems by taking advantage of both radiant and convective heat transfer to remove space heating load. There are rare studies on differences of heating systems between all-air system and radiant floor system. This paper uses the method of simulation based on state-space to calculate the indoor temperature and wall temperature of each system and shows how the dynamic heat transfer in rooms conditioned by a radiant system is different from an air system. Then this paper analyses the changes of indoor temperature of these two systems, finding out the differences between all-air heating system and radiant floor heating system to help the designer choose a more suitable heating system.

Keywords: Radiant floor, all-air system, thermal comfort, simulation, heating system.

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Authors: Yukiyo Yamamoto, Jun Furuya, Shintaro Kobayashi

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Using 1km grid datasets representing monthly mean precipitation, monthly mean temperature, and dry matter production (DMP), we considered the regional plant production ability in Southeast and South Asia, and also employed pixel-by-pixel correlation analysis to assess the intensity of relation between climate factors and plant production. While annual DMP in South Asia was approximately less than 2,000kg, the one in most part of Southeast Asia exceeded 2,500 - 3,000kg. It suggested that plant production in Southeast Asia was superior to South Asia, however, Rain-Use Efficiency (RUE) representing dry matter production per 1mm precipitation showed that inland of Indochina Peninsula and India were higher than islands in Southeast Asia. By the results of correlation analysis between climate factors and DMP, while the area in most parts of Indochina Peninsula indicated negative correlation coefficients between DMP and precipitation or temperature, the area in Malay Peninsula and islands showed negative correlation to precipitation and positive one to temperature, and most part of India dominating South Asia showed positive to precipitation and negative to temperature. In addition, the areas where the correlation coefficients exceeded |0.8| were regarded as “susceptible" to climate factors, and the areas smaller than |0.2| were “insusceptible". By following the discrimination, the map implying expected impacts by climate change was provided.

Keywords: Asia, correlation analysis, plant production, precipitation, temperature.

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Authors: Megawati, Wahyudi B. Sediawan, Hary Sulistyo, Muslikhin Hidayat

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Rice husk is a lignocellulosic source that can be converted to ethanol. Three hundreds grams of rice husk was mixed with 1 L of 0.18 N sulfuric acid solutions then was heated in an autoclave. The reaction was expected to be at constant temperature (isothermal), but before that temperature was achieved, reaction has occurred. The first liquid sample was taken at temperature of 140 0C and repeated every 5 minute interval. So the data obtained are in the regions of non-isothermal and isothermal. It was observed that the degradation has significant effects on the ethanol production. The kinetic constants can be expressed by Arrhenius equation with the frequency factors for hydrolysis and sugar degradation of 1.58 x 105 1/min and 2.29 x 108 L/mole/min, respectively, while the activation energies are 64,350 J/mole and 76,571 J/mole. The highest ethanol concentration from fermentation is 1.13% v/v, attained at 220 0C.

Keywords: degradation, ethanol, hydrolysis, rice husk

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Authors: Megawati, Wahyudi B. Sediawan, Hary Sulistyo, Muslikhin Hidayat

Abstract:

Rice husk is a lignocellulosic source that can be converted to ethanol. Three hundreds grams of rice husk was mixed with 1 L of 0.18 N sulfuric acid solutions then was heated in an autoclave. The reaction was expected to be at constant temperature (isothermal), but before that temperature was achieved, reaction has occurred. The first liquid sample was taken at temperature of 140 0C and repeated every 5 minute interval. So the data obtained are in the regions of non-isothermal and isothermal. It was observed that the degradation has significant effects on the ethanol production. The kinetic constants can be expressed by Arrhenius equation with the frequency factors for hydrolysis and sugar degradation of 1.58 x 105 min-1 and 2.29 x 108 L/mole-min, respectively, while the activation energies are 64,350 J/mole and 76,571 J/mole. The highest ethanol concentration from fermentation is 1.13% v/v, attained at 220 0C.

Keywords: degradation, ethanol, hydrolysis, rice husk.

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Authors: S. Sendilkumar, B. L. Mathur, Joseph Henry

Abstract:

A new approach for protection of power transformer is presented using a time-frequency transform known as Wavelet transform. Different operating conditions such as inrush, Normal, load, External fault and internal fault current are sampled and processed to obtain wavelet coefficients. Different Operating conditions provide variation in wavelet coefficients. Features like energy and Standard deviation are calculated using Parsevals theorem. These features are used as inputs to PNN (Probabilistic neural network) for fault classification. The proposed algorithm provides more accurate results even in the presence of noise inputs and accurately identifies inrush and fault currents. Overall classification accuracy of the proposed method is found to be 96.45%. Simulation of the fault (with and without noise) was done using MATLAB AND SIMULINK software taking 2 cycles of data window (40 m sec) containing 800 samples. The algorithm was evaluated by using 10 % Gaussian white noise.

Keywords: Power Transformer, differential Protection, internalfault, inrush current, Wavelet Energy, Db9.

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Authors: Hakan Işık, Esra Saraçoğlu

Abstract:

In this study, a comparison of two control methods, Proportional Control (PC) and Fuzzy Logic Control (FLC), which have been used to develop an ideal thermoelectric renal hypothermia system in order to use in renal surgery, has been carried out. Since the most important issues in long-lasting parenchymatous renal surgery are to provide an operation medium free of blood and to prevent renal dysfunction in the postoperative period, control of the temperature has become very important in renal surgery. The final product is seriously affected from the changes in temperature, therefore, it is necessary to reach some desired temperature points quickly and avoid large overshoot. PIC16F877 microcontroller has been used as controller for both of these two methods. Each control method can simply ensure extra renal hypothermia in the targeted way. But investigation of advantages and disadvantages of every control method to each other is aimed and carried out by the experimental implementations. Shortly, investigation of the most appropriate method to use for development of system and that can be applied to people safely in the future, has been performed. In this sense, experimental results show that fuzzy logic control gives out more reliable responses and efficient performance.

Keywords: renal hypothermia, renal cooling, temperature control, proportional control fuzzy logic control

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