Search results for: track mass capacity

Authors: Linjun Wu, Shihua Zhu, Xingle Feng

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In an Orthogonal Frequency Division Multiplexing (OFDM) systems, the Peak to Average power Ratio (PAR) is high. The clipping signal scheme is a useful and simple method to reduce the PAR. However, it introduces additional noise that degrades the systems performance. We propose an oversampling scheme to deal with the received signal in order to reduce the clipping noise by using Finite Impulse Response (FIR) filter. Coefficients of filter are obtained by correlation function of the received signal and the oversampling information at receiver. The performance of the proposed technique is evaluated for frequency selective channel. Results show that the proposed scheme can mitigate the clipping noise significantly for OFDM systems and in order to maintain the system's capacity, the clipping ratio should be larger than 2.5.

Keywords: Orthogonal frequency division multiplexing, peak-to-average power ratio, oversampling.

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Authors: A. M. Gheitaghy, H. Saffari, G. Q. Zhang

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Numerical approach based on the electrical simulation method is proposed to solve a nonlinear transient heat conduction problem with nonlinear boundary for a spherical body. This problem represents a strong nonlinearity in both the governing equation for temperature dependent thermal property and the boundary condition for combined convective and radiative cooling. By analysing the equivalent electrical model using the electrical circuit simulation program HSPICE, transient temperature and heat flux distributions at sphere can be obtained easily and fast. The solutions clearly illustrate the effect of the radiation-conduction parameter N_rc, the Biot number and the linear coefficient of temperature dependent conductivity and heat capacity. On comparing the results with corresponding numerical solutions, the accuracy and efficiency of this computational method is found to be good.

Keywords: Convective boundary, radiative boundary, electrical simulation method, nonlinear heat conduction, spherical coordinate.

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Authors: Jean-Alain Grunchec, Jules Hernández-Sánchez, Sara Knott

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Some meta-schedulers query the information system of individual supercomputers in order to submit jobs to the least busy supercomputer on a computational Grid. However, this information can become outdated by the time a job starts due to changes in scheduling priorities. The MSR scheme is based on Multiple Simultaneous Requests and can take advantage of opportunities resulting from these priorities changes. This paper presents the SWARM meta-scheduler, which can speed up the execution of large sets of tasks by minimizing the job queuing time through the submission of multiple requests. Performance tests have shown that this new meta-scheduler is faster than an implementation of the MSR scheme and the gLite meta-scheduler. SWARM has been used through the GridQTL project beta-testing portal during the past year. Statistics are provided for this usage and demonstrate its capacity to achieve reliably a substantial reduction of the execution time in production conditions.

Keywords: Grid computing, multiple simultaneous requests, fault tolerance, GridQTL.

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Authors: S. Sobhanian, H. Naghshara, N. Sadeghi, S. Khorram

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The absolute Cu atoms density in Cu(2S1/2ÔåÉ2P1/2) ground state has been measured by Resonance Optical Absorption (ROA) technique in a DC magnetron sputtering deposition with argon. We measured these densities under variety of operation conditions: pressure from 0.6 μbar to 14 μbar, input power from 10W to 200W and N2 mixture from 0% to 100%. For measuring the gas temperature, we used the simulation of N2 rotational spectra with a special computer code. The absolute number density of Cu atoms decreases with increasing the N2 percentage of buffer gas at any conditions of this work. But the deposition rate, is not decreased with the same manner. The deposition rate variation is very small and in the limit of quartz balance measuring equipment accuracy. So we conclude that decrease in the absolute number density of Cu atoms in magnetron plasma has not a big effect on deposition rate, because the diffusion of Cu atoms to the chamber volume and deviation of Cu atoms from direct path (towards the substrate) decreases with increasing of N2 percentage of buffer gas. This is because of the lower mass of N2 atoms compared to the argon ones.

Keywords: Deposition rate, Resonance Optical Absorption, Sputtering.

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Authors: Nahid-Al-Masood, Jubaer Ahmed, Amina Hasan Abedin, S. R. Deeba, Faeza Hafiz, Mahmuda Begum

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An electric utility-s main concern is to plan, design, operate and maintain its power supply to provide an acceptable level of reliability to its users. This clearly requires that standards of reliability be specified and used in all three sectors of the power system, i.e., generation, transmission and distribution. That is why reliability of a power system is always a major concern to power system planners. This paper presents the reliability analysis of Bangladesh Power System (BPS). Reliability index, loss of load probability (LOLP) of BPS is evaluated using recursive algorithm and considering no de-rated states of generators. BPS has sixty one generators and a total installed capacity of 5275 MW. The maximum demand of BPS is about 5000 MW. The relevant data of the generators and hourly load profiles are collected from the National Load Dispatch Center (NLDC) of Bangladesh and reliability index 'LOLP' is assessed for the period of last ten years.

Keywords: Recursive algorithm, LOLP, forced outage rate, cumulative probability.

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Authors: Farshad Mehrabi, Ali kheirodin, Mohsen Gerami

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Ambiguities in effects of earthquake on various structures in all earthquake codes would necessitate more study and research concerning influential factors on dynamic behavior. Previous studies which were done on different features in different buildings play a major role in the type of response a structure makes to lateral vibrations. Diagnosing each of these irregularities can help structure designers in choosing appropriate setbacks for decreasing possible damages. Therefore vertical setback is one of the irregularity factors in the height of the building where can be seen in skyscrapers and hotels. Previous researches reveal notable changes in the place of these setbacks showing dynamic response of the structure. Consequently analyzing 48 models of concrete frames for 3, 6 and 9 stories heights with three different bays in general shape of a surface decline by height have been constructed in ETABS2000 software, and then the shape effect of each and every one of these frames in period scale has been discussed. The result of this study reveals that not only mass, stiffness and height but also shape of the frame is influential.

Keywords: period, concrete frame, irregularity in height, decrease in plan surface, dynamic behavior

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Authors: Lütfü Saribulut, Mehmet Tümay, İlyas Eker

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FACTS devices are used to control the power flow, to increase the transmission capacity and to optimize the stability of the power system. One of the most widely used FACTS devices is Unified Power Flow Controller (UPFC). The controller used in the control mechanism has a significantly effects on controlling of the power flow and enhancing the system stability of UPFC. According to this, the capability of UPFC is observed by using different control mechanisms based on P, PI, PID and fuzzy logic controllers (FLC) in this study. FLC was developed by taking consideration of Takagi- Sugeno inference system in the decision process and Sugeno-s weighted average method in the defuzzification process. Case studies with different operating conditions are applied to prove the ability of UPFC on controlling the power flow and the effectiveness of controllers on the performance of UPFC. PSCAD/EMTDC program is used to create the FLC and to simulate UPFC model.

Keywords: FACTS, Fuzzy Logic Controller, UPFC.

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Authors: Yidan Shao

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With the advancement of the economy, technology promotes online teaching, and learning has become one of the common features in the educational field. Meanwhile, the dramatic expansion of the online environment provides opportunities for more learners, including second language learners. A greater command of vocabulary improves students’ learning capacity, and word acquisition and development play a critical role in learning. Furthermore, the Word Wall is an effective tool to improve students’ knowledge of words, which works for a wide range of age groups. Therefore, this study is going to use the Word Wall as an intervention to examine whether it can bring some memorization changes in an online English language class for a second language learner based on the word morphology method. The participant will take ten courses in the experiment as it plans. The findings show that the Word Wall activity plays a slight role in improving word memorizing, but it does affect instant memorization. If longer periods and more comprehensive designs of research can be applied, it is expected to have more value.

Keywords: Second language acquisition, word morphology, word memorization, the Word Wall.

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Authors: Jason P. Michaud, Connor P. Speer, David A. Miller, David S. Nobes

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An experimental study on finned-tube radiators has been conducted. Three radiators found in desktop computers sized for 120 mm fans were tested in steady and pulsatile flows of ambient air over a Reynolds number range of  50 < Re < 900. Water at 60 °C was circulated through the radiators to maintain a constant fin temperature during the tests. For steady flow, it was found that the heat transfer rate increased linearly with the mass flow rate of air. The pulsatile flow experiments showed that frequency of pulsation had a negligible effect on the heat transfer rate for the range of frequencies tested (0.5 Hz – 2.5 Hz). For all three radiators, the heat transfer rate was decreased in the case of pulsatile flow. Linear heat transfer correlations for steady and pulsatile flow were calculated in terms of Reynolds number and Nusselt number.

Keywords: Finned-tube heat exchangers, radiators, heat transfer correlations, pulsatile flow, computer radiators.

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Authors: Kuncoro Harto Widodo, Yandra Rahadian Perdana, Iwan Puja Riyadi

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Effectiveness and efficiency of food distribution is necessary to maintain food security in a region. Food supply varies among regions depending on their production capacity; therefore, it is necessary to regulate food distribution. Sea transportation could play a great role in the food distribution system. To play this role and to support transportation needs in the Eastern Indonesia, sea transportation shall be supported by fleet which is adequate and reliable, both in terms of load and worthiness. This research uses Linear Programming (LP) method to analyze food distribution pattern in order to determine the optimal distribution system. In this research, transshipment points have been selected for regions in one province. Comparison between result of modeling and existing shipping route reveals that from 369 existing routes, 54 routes are used for transporting rice, corn, green bean, peanut, soybean, sweet potato, and cassava.

Keywords: Distribution, Sea Transportation, Eastern Indonesia (KTI), Linear Programming (LP).

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Authors: Sulata Maharana, B Biswas, Adity Ganguly, Ashok Kumar

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In this paper, the requirement for Coke quality prediction, its role in Blast furnaces, and the model output is explained. By applying method of Artificial Neural Networking (ANN) using back propagation (BP) algorithm, prediction model has been developed to predict CSR. Important blast furnace functions such as permeability, heat exchanging, melting, and reducing capacity are mostly connected to coke quality. Coke quality is further dependent upon coal characterization and coke making process parameters. The ANN model developed is a useful tool for process experts to adjust the control parameters in case of coke quality deviations. The model also makes it possible to predict CSR for new coal blends which are yet to be used in Coke Plant. Input data to the model was structured into 3 modules, for tenure of past 2 years and the incremental models thus developed assists in identifying the group causing the deviation of CSR.

Keywords: Artificial Neural Networks, backpropagation, CokeStrength after Reaction, Multilayer Perceptron.

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Authors: Shannon M. Chance, Pamela L. Eddy, Gavin Duffy, Brian Bowe, Jen Harvey

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Educational institutions often implement policies with the intention of influencing how learning and teaching occur. Generally, such policies are not as effective as their makers would like; changing the behavior of third-level teachers proves difficult. Nevertheless, a policy instituted in 2006 at the Dublin Institute of Technology has met with success: each newly hired faculty member must have a post-graduate qualification in “Learning and Teaching" or successfully complete one within the first two years of employment. The intention is to build teachers- knowledge about student-centered pedagogies and their capacity to implement them. As a result of this policy (and associated programs that support it), positive outcomes are readily apparent. Individual teachers who have completed the programs have implemented significant change at the course and program levels. This paper introduces the policy, identifies outcomes in relation to existing theory, describes research underway, and pinpoints areas where organizational learning has occurred.

Keywords: Faculty Development, Institutional Policy, Learning and Teaching, Postgraduate Qualification, Professional Development.

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Authors: Kolay, P.K., Sii, H. Y., Taib, S.N.L.

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This paper presents the stabilization potential of Class F pond ash (PA) from a coal fired thermal power station on tropical peat soil. Peat or highly organic soils are well known for their high compressibility, natural moisture content, low shear strength and long-term settlement. This study investigates the effect of different amount (i.e., 5, 10, 15 and 20%) of PA on peat soil, collected from Sarawak, Malaysia, mainly compaction and unconfined compressive strength (UCS) properties. The amounts of PA added to the peat soil sample as percentage of the dry peat soil mass. With the increase in PA content, the maximum dry density (MDD) of peat soil increases, while the optimum moisture content (OMC) decreases. The UCS value of the peat soils increases significantly with the increase of PA content and also with curing periods. This improvement on compressive strength of tropical peat soils indicates that PA has the potential to be used as a stabilizer for tropical peat soil. Also, the use of PA in soil stabilization helps in reducing the pond volume and achieving environment friendly as well as a sustainable development of natural resources.

Keywords: Compaction, Peat soil, Pond ash, Stabilization.

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Authors: Rui Yu, Huiqing Ying

Abstract:

To enhance installation security, a LNG storage in Rudong of Jiangsu province was adopted as a practical work, and it was analyzed by nonlinear finite element method to research overall and local stability performance, as well as the stress and deformation under the action of wind load and self-weight. Results indicate that deformation is tiny when steel mesh maintains as an overall ring, and stress caused by vertical bending moment and tension of bottom tie wire are also in the safe range. However, axial forces of lap reinforcement in adjacent steel mesh exceed the ultimate bearing capacity of tie wire. Hence, tie wires are ruptured; single mesh loses lateral connection and turns into monolithic status as the destruction of overall structure. Further more, monolithic steel mesh is led to collapse by the damage of bottom connection. So, in order to prevent connection failure and enhance installation security, the overlapping parts of steel mesh should be taken more reliable measures.

Keywords: low temperature steel mesh, installation stability, nonlinear finite element, tie wire.

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Authors: N. Behidj-Benyounes, S. Bennaamane, F. Zohra Bissaad, N. Chebouti, H. Mohandkaci, N. Abdalaziz, S. Iddou

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In this study, we are interested in a species of the family of Asteraceae (Tagetes erecta). This family is considered as a source of antimicrobial extracts with strong capacity. The extraction of the flavonoids is carried out by the method of liquid/liquid with the use of successive solvents. Afterwards, we evaluated the biological activity of the flavonoids on five pathogenic bacterial stocks such as Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus and two stocks of yeasts to knowing Candida albicans) and Saccharomyces cerevisiae, by employing the method of the aromatogramme starting from a solid disc. The result of the antimicrobial activity shows an action and a variable degree of sensitivity according to bacterial stocks tested. It will be noted that the flavonoids have an inhibiting effect on E. coli, B. subtilis, K. pneumoniae and S. aureus. But a resistance with respect to the extract by P. aeruginosa, C. albicans and S. cerevisiae is to be mentioned.

Keywords: Antimicrobial activity, flavonoids, microbial strains, Tagetes erecta L.

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Authors: A. H. Azni, Madihah Mohd Saudi, Azreen Azman, Ariff Syah Johari

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Sensor Network are emerging as a new tool for important application in diverse fields like military surveillance, habitat monitoring, weather, home electrical appliances and others. Technically, sensor network nodes are limited in respect to energy supply, computational capacity and communication bandwidth. In order to prolong the lifetime of the sensor nodes, designing efficient routing protocol is very critical. In this paper, we illustrate the existing routing protocol for wireless sensor network using data centric approach and present performance analysis of these protocols. The paper focuses in the performance analysis of specific protocol namely Directed Diffusion and SPIN. This analysis reveals that the energy usage is important features which need to be taken into consideration while designing routing protocol for wireless sensor network.

Keywords: Data Centric Approach, Directed Diffusion, SPIN WSN Routing Protocol.

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Authors: Evgeniy Burlutskiy

Abstract:

The paper presents a one-dimensional transient mathematical model of compressible non-isothermal multicomponent fluid mixture flow in a pipe. The set of the mass, momentum and enthalpy conservation equations for gas phase is solved in the model. Thermo-physical properties of multi-component gas mixture are calculated by solving the Equation of State (EOS) model. The Soave-Redlich-Kwong (SRK-EOS) model is chosen. Gas mixture viscosity is calculated on the basis of the Lee-Gonzales- Eakin (LGE) correlation. Numerical analysis of rapid gas decompression process in rich and base natural gases is made on the basis of the proposed mathematical model. The model is successfully validated on the experimental data [1]. The proposed mathematical model shows a very good agreement with the experimental data [1] in a wide range of pressure values and predicts the decompression in rich and base gas mixtures much better than analytical and mathematical models, which are available from the open source literature.

Keywords: Mathematical model, Multi-Component gas mixture flow, Rapid Gas Decompression

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Authors: S.T. El Sheltawy, A. A. Refaat

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Until recently, energy security and climate change were considered separate issues to be dealt with by policymakers. The two issues are now converging, challenging the security and climate communities to develop a better understanding of how to deal with both issues simultaneously. Although Egypt is not a major contributor to the world's total GHG emissions, it is particularly vulnerable to the potential effects of global climate change such as rising sea levels and changed patterns of rainfall in the Nile Basin. Climate change is a major threat to sustainable growth and development in Egypt, and the achievement of the Millennium Development Goals. Egypt-s capacity to respond to the challenges of climate instability will be expanded by improving overall resilience, integrating climate change goals into sustainable development strategies, increasing the use of modern energy systems with reduced carbon intensity, and strengthening international initiatives. This study seeks to establish a framework for considering the complex and evolving links between energy security and climate change, applicable to Egypt.

Keywords: climate change, climate policy, cnergy policy, energy security, sustainable development

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Authors: M. Abdulkadir, V. Hernandez-Perez

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The characteristics of fluid flow and phase separation in an oil-water separator were numerically analysed as part of the work presented herein. Simulations were performed for different velocities and droplet diameters, and the way this parameters can influence the separator geometry was studied. The simulations were carried out using the software package Fluent 6.2, which is designed for numerical simulation of fluid flow and mass transfer. The model consisted of a cylindrical horizontal separator. A tetrahedral mesh was employed in the computational domain. The condition of two-phase flow was simulated with the two-fluid model, taking into consideration turbulence effects using the k-ε model. The results showed that there is a strong dependency of phase separation on mixture velocity and droplet diameter. An increase in mixture velocity will bring about a slow down in phase separation and as a consequence will require a weir of greater height. An increase in droplet diameter will produce a better phase separation. The simulations are in agreement with results reported in literature and show that CFD can be a useful tool in studying a horizontal oilwater separator.

Keywords: CFD, droplet diameter, mixture velocity

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Authors: Hocine Hammoum, Karima Bouzelha, Lounis Ziani, Lounis Hamitouche

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In this paper, we study a complex structure which is an apartment building surmounted by a reinforced concrete water tank. The tank located on the top floor of the building is a container with capacity of 1000 m³. The building is complex in its design, its calculation and by its behavior under earthquake effect. This structure located in Algiers and aged of 53 years has been subjected to several earthquakes, but the earthquake of May 21^st, 2003 with a magnitude of 6.7 on the Richter scale that struck Boumerdes region at 40 Kms East of Algiers was fatal for it. It was downgraded after an investigation study because the central core sustained serious damage. In this paper, to estimate the degree of its damages, the seismic performance of the structure will be evaluated taking into account the hydrodynamic effect, using a static equivalent nonlinear analysis called pushover.

Keywords: Performance analysis, building, reinforced concrete tank, seismic analysis, nonlinear analysis, hydrodynamic, pushover.

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Authors: B. Nasri, M. Bensaada

Abstract:

We present a simulation and realization of a battery charge regulator (BCR) in microsatellite earth observation. The tests were performed on battery pack 12volt, capacity 24Ah and the solar array open circuit voltage of 100 volt and optimum power of about 250 watt. The battery charge is made by solar module. The principle is to adapt the output voltage of the solar module to the battery by using the technique of pulse width modulation (PWM). Among the different techniques of charge battery, we opted for the technique of the controller ON/OFF is a standard technique and simple, it-s easy to be board executed validation will be made by simulation "Proteus Isis Professional software ". The circuit and the program of this prototype are based on the PIC16F877 microcontroller, a serial interface connecting a PC is also realized, to view and save data and graphics in real time, for visualization of data and graphs we develop an interface tool “visual basic.net (VB)--.

Keywords: Battery Charge Regulator, Batteries, Buck converter, Power System, Power Conditioning, Power Distribution, Solar arrays.

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Authors: S.Baskar, P.S.Ramkumar, R.Kesavan

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This paper presents a new heuristic algorithm useful for long-term planning of survivable WDM networks. A multi-period model is formulated that combines network topology design and capacity expansion. The ability to determine network expansion schedules of this type becomes increasingly important to the telecommunications industry and to its customers. The solution technique consists of a Genetic Algorithm that allows generating several network alternatives for each time period simultaneously and shortest-path techniques to deduce from these alternatives a least-cost network expansion plan over all time periods. The multi-period planning approach is illustrated on a realistic network example. Extensive simulations on a wide range of problem instances are carried out to assess the cost savings that can be expected by choosing a multi-period planning approach instead of an iterative network expansion design method.

Keywords: Wavelength Division Multiplexing, Genetic Algorithm, Network topology, Multi-period reliable network planning

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Authors: Prakash G L, Thejaswini M, S H Manjula, K R Venugopal, L M Patnaik

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Wireless sensor network can be applied to both abominable and military environments. A primary goal in the design of wireless sensor networks is lifetime maximization, constrained by the energy capacity of batteries. One well-known method to reduce energy consumption in such networks is data aggregation. Providing efcient data aggregation while preserving data privacy is a challenging problem in wireless sensor networks research. In this paper, we present privacy-preserving data aggregation scheme for additive aggregation functions. The Cluster-based Private Data Aggregation (CPDA)leverages clustering protocol and algebraic properties of polynomials. It has the advantage of incurring less communication overhead. The goal of our work is to bridge the gap between collaborative data collection by wireless sensor networks and data privacy. We present simulation results of our schemes and compare their performance to a typical data aggregation scheme TAG, where no data privacy protection is provided. Results show the efficacy and efficiency of our schemes.

Keywords: Aggregation, Clustering, Query Processing.

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Authors: Elnasharty M., El Sharaby A., Nor El-din A.

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The gustatory system allows animals to distinguish varieties of food and affects greatly the consumption of food, hence the health and growth of animals. In the current study, we investigated the histogenesis of vallate papillae (VLP) in the rabbit tongue using light and scanning electron microscopy. Samples were obtained from rabbit embryos at the embryonic days 16-30 (E16-30), and from newborns until maturity; 6 months. At E16, the first primordia of vallate papillae were observed as small pits on the surface epithelium of the tongue-s root. At E18, the caudal part was prominent with loose mesenchymal tissue core; meanwhile the rostral part of the papilla was remained as a thick mass of epithelial cells. At E20-24, the side epithelium formed the primitive annular groove. At E26, the primitive taste buds appeared only at the papillary surface and reached their maturity by E28. The annular groove started to appear at E26 became more defined at E28. The definitive vallate papillae with substantial number of apparently mature taste buds were observed by the end of the second week. We conclude that the vallate papillae develop early and mature during the early postnatal life.

Keywords: Rabbit, vallate papillae, histogenesis, taste buds.

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Authors: Ehsan Firouzfar, Maryam Attaran

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Heat pipes are two-phase heat transfer devices with high effective thermal conductivity. Due to the high heat transport capacity, heat exchanger with heat pipes has become much smaller than traditional heat exchangers in handling high heat fluxes. With the working fluid in a heat pipe, heat can be absorbed on the evaporator region and transported to the condenser region where the vapour condenses releasing the heat to the cooling media. Heat pipe technology has found increasing applications in enhancing the thermal performance of heat exchangers in microelectranics, energy saving in HVAC systems for operating rooms,surgery centers, hotels, cleanrooms etc, temperature regulation systems for the human body and other industrial sectors. Development activity in heat pipe and thermosyphon technology in asia in recent years is surveyed. Some new results obtained in Australia and other countries are also included.

Keywords: Heat pipe heat exchanger, Thermosyphone, effectiveness, HVAC system, energy saving, temperature regulation.

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Authors: Noraziah A. Y., Mashitah M. D., Subhash Bhatia

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Fructooligosaccharides derived from microbial enzyme especially from fungal sources has been received particular attention due to its beneficial effects as prebiotics and mass production. However, fungal fermentation is always cumbersome due to its broth rheology problem that will eventually affect the production of FOS. This study investigated the efficiency of immobilized cell system using rotating fibrous bed bioreactor (RFBB) in producing fructooligosaccharides (FOS). A comparative picture with respect to conventional stirred tank bioreactor (CSTB) and RFBB has been presented. To demonstrate the effect of agitation intensity and aeration rate, a laboratory-scale bioreactor 2.5 L was operated in three phases (high, medium, low) for 48 hours. Agitation speed has a great influence on P. simplicissimum fermentation for FOS production, where the volumetric FOS productivity using RFBB is increased with almost 4 fold compared to the FOS productivity in CSTB that only 0.319 g/L/h. Rate of FOS production increased up to 1.2 fold when immobilized cells system was employed at aeration rate similar to the freely suspended cells at 2.0 vvm.

Keywords: Fructooligosaccharides, immobilized, productivity, prebiotics.

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Authors: Bahareh Aghasi, Ahmad Jalalian, Naser Honarjoo

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Land use change, if not based on proper scientific investigation affects other physical, chemical, and biological properties of soil and leading to increased destruction and erosion. It was imperative to study the effects of changing rangelands to farmlands on some Soil quality indexes. Undisturbed soil samples were collected from the depths of 0-10 and 10-30 centimeter in pasture with good vegetation cover(GP), pasture with medium vegetation cover(MP), abandoned dry land farming(ADF) and degraded dry land farming(DDF) land uses in Ghareh Aghaj watershed of Isfahan province. The results revealed that organic matter(OM), cation exchange capacity(CEC) and available potassium(AK) decreasing in the depth of 0-10 centimeter were 66.6, 38.8 and 70 percent and in the depth of 10-30 centimeter were 58, 61.4 and 83.5 percent respectively in DDF comparison with GP. Concerning to the results, it seems that land use change can decrease soil quality and increase soil degradation and lead in undesirable consequences.

Keywords: Land use change, Soil degradation, Soil quality

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Authors: Marianna I. Triantou, Konstantina I. Stathi, Petroula A. Tarantili

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In the present study, the incorporation of graphene into blends of acrylonitrile-butadiene-styrene terpolymer with polypropylene (ABS/PP) was investigated focusing on the improvement of their thermomechanical characteristics and the effect on their rheological behavior. The blends were prepared by melt mixing in a twin-screw extruder and were characterized by measuring the MFI as well as by performing DSC, TGA and mechanical tests. The addition of graphene to ABS/PP blends tends to increase their melt viscosity, due to the confinement of polymer chains motion. Also, graphene causes an increment of the crystallization temperature (Tc), especially in blends with higher PP content, because of the reduction of surface energy of PP nucleation, which is a consequence of the attachment of PP chains to the surface of graphene through the intermolecular CH-π interaction. Moreover, the above nanofiller improves the thermal stability of PP and increases the residue of thermal degradation at all the investigated compositions of blends, due to the thermal isolation effect and the mass transport barrier effect. Regarding the mechanical properties, the addition of graphene improves the elastic modulus, because of its intrinsic mechanical characteristics and its rigidity, and this effect is particularly strong in the case of pure PP.

Keywords: Acrylonitrile-butadiene-styrene terpolymer, blends, graphene, polypropylene.

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Authors: Md. Alamgir Hossain, Md. Raju Ahmed

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Scarcity in energy sector is a major problem, which can hamper the growing development of a country. Bangladesh is one of the electricity-deprived countries; however, the energy demand of Bangladesh is increasing day by day. Due to the shortage of natural resources and environmental issues, many nations are now moving towards renewable energy. Among various form of renewable energy, wind energy is one of most potential source. In this paper, the present energy condition of Bangladesh is discussed and the necessity of moving towards renewable energy is clarified. The wind speed found at different locations at different heights and different years from the survey of several organizations are presented. Although, the results of installed low capacity wind turbines (from few kW to few tens of kW) operated by private or government organization at different places in Bangladesh are not so encouraging; however, it is shown that Bangladesh has a high potential of using large wind turbine (MW range) for capturing wind energy at different places. The present condition of wind energy in Bangladesh and other countries in the world are also presented to emphasize the requisite of moving towards wind energy.

Keywords: Renewable energy, wind speed, wind power, modern wind turbine, scarcity of power and gas crisis.

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Authors: S. Prem Kumar, H. Thameemul Ansari, V. Saminadan

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A smart grid is an emerging technology in the power delivery system which provides an intelligent, self-recovery and homeostatic grid in delivering power to the users. Smart grid communication network provides transmission capacity for information transformation within the connected nodes in the network, in favor of functional and operational needs. In the electric grids communication network delay is based on choosing the appropriate technology and the types of devices enforced. In distinction, the combination of IEEE 802.16 based WiMAX and IEEE 802.11 based WiFi technologies provides improved coverage and gives low delay performances to meet the smart grid needs. By incorporating this method in Wide Area Monitoring System (WAMS) and Advanced Metering Infrastructure (AMI) the performance of the smart grid will be considerably improved. This work deals with the implementation of WiMAX-WLAN integrated network architecture for WAMS and AMI in the smart grid.

Keywords: WiMAX, WLAN, WAMS, Smart Grid, HetNet, AMI.

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