Search results for: Non sinusoidal and unbalanced voltage conditions.
1777 Fatigue Life of an Anti-Roll Bar of a Passenger Vehicle
Authors: J. Marzbanrad, A. Yadollahi
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In the present paper, Fatigue life assessment of an anti-roll bar component of a passenger vehicle, is investigated by ANSYS 11 software. A stress analysis is also carried out by the finite element technique for the determination of highly stressed regions on the bar. Anti-roll bar is a suspension element used at the front, rear, or at both ends of a car that reduces body roll by resisting any unequal vertical motion between the pair of wheels to which it is connected. As a first stage, fatigue damage models proposed by some well-known references and the corresponding assumptions are discussed and some enhancements are proposed. Then, fracture analysis of an anti-roll bar of an automobile is carried out. The analysed type of the anti-roll bar is especially important as many cases are reported about the fracture after a 100,000 km of travel fatigue and fracture conditions. This paper demonstrates fatigue life of an anti-roll bar and then evaluated by experimental analytically results from other researcher.Keywords: Anti-roll bar, Fracture, Fatigue life, Random loading
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 35521776 Extraction and Characterization of Oil from Avocado Peels
Authors: Tafere Aga Bullo
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The peels of avocados, like other fruit peels, are commonly discarded, not knowing their potential use. This study carried out to extract oils from avocado peels and to characterize the extracted oils with the view to determine their suitability for consumption and other uses. Soxhlet apparatus was used for extraction using n-hexane as a solvent, which is chosen based on the fact that it has a very low value of toxicity and a great extraction rate. The proximate analysis and physicochemical properties of the extracted oil were investigated. The percentage yield of oil extracted from the peel was found to be 40.6%. From this study, the optimum operating conditions for the extraction of oil from avocado peel oil for the particle size of 2.6 mm, solvent type N-hexane and extraction time of 3-5 hr. were considered. A general factorial design was applied to investigate the effect of process variables on oil yield. Maximum oil yield of 40.6% was obtained at an extraction time of 5 hr. The extracted avocado peel oil can be widely used in pharmaceutical and energy production.
Keywords: Avocado fruits, avocado oil, avocado peel oil, characterization.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 9441775 Technical Support of Intracranial Single Unit Activity Measurement
Authors: Richard Grünes, Karel Roubik
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The article deals with technical support of intracranial single unit activity measurement. The parameters of the whole measuring set were tested in order to assure the optimal conditions of extracellular single-unit recording. Metal microelectrodes for measuring the single-unit were tested during animal experiments. From signals recorded during these experiments, requirements for the measuring set parameters were defined. The impedance parameters of the metal microelectrodes were measured. The frequency-gain and autonomous noise properties of preamplifier and amplifier were verified. The measurement and the description of the extracellular single unit activity could help in prognoses of brain tissue damage recovery.
Keywords: Measuring set, metal microelectrodes, single-unit, noise, impedance parameters, gain characteristics.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 15351774 TS Fuzzy Controller to Stochastic Systems
Authors: Joabe Silva, Ginalber Serra
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This paper proposes the analysis and design of robust fuzzy control to Stochastic Parametrics Uncertaint Linear systems. This system type to be controlled is partitioned into several linear sub-models, in terms of transfer function, forming a convex polytope, similar to LPV (Linear Parameters Varying) system. Once defined the linear sub-models of the plant, these are organized into fuzzy Takagi- Sugeno (TS) structure. From the Parallel Distributed Compensation (PDC) strategy, a mathematical formulation is defined in the frequency domain, based on the gain and phase margins specifications, to obtain robust PI sub-controllers in accordance to the Takagi- Sugeno fuzzy model of the plant. The main results of the paper are based on the robust stability conditions with the proposal of one Axiom and two Theorems.Keywords: Fuzzy Systems; Robust Stability, Stochastic Control, Stochastic Process
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 16991773 Pricing Strategy Selection Using Fuzzy Linear Programming
Authors: Elif Alaybeyoğlu, Y. Esra Albayrak
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Marketing establishes a communication network between producers and consumers. Nowadays, marketing approach is customer-focused and products are directly oriented to meet customer needs. Marketing, which is a long process, needs organization and management. Therefore strategic marketing planning becomes more and more important in today’s competitive conditions. Main focus of this paper is to evaluate pricing strategies and select the best pricing strategy solution while considering internal and external factors influencing the company’s pricing decisions associated with new product development. To reflect the decision maker’s subjective preference information and to determine the weight vector of factors (attributes), the fuzzy linear programming technique for multidimensional analysis of preference (LINMAP) under intuitionistic fuzzy (IF) environments is used.
Keywords: IF Sets, LINMAP, MAGDM, Marketing.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 22641772 Pervasiveness of Aflatoxin in Peanuts Growing in the Area of Pothohar, Pakistan
Authors: Mateen Abbas, Abdul Muqeet Khan, Muhammad Rafique Asi, Javed Akhtar
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Mycotoxin (aflatoxins) contamination of peanuts is a great concern for human health. A total of 72 samples of unripe, roasted, and salty peanuts were collected randomly from Pothohar plateau of Pakistan for the assessment of aflatoxin. Samples were dried, ground and extracted by acetonitrile (84%). The filtered extracts were cleaned up by MycoSep-226 and analyzed by high performance liquid chromatography with flourescence detector. Quantification limit of Aflatoxin was 1 μg/kg and 70% Recovery was observed in spiked samples in the range 1–10 μg/kg. The screening of mycotoxins indicated that aflatoxins were present in most of the samples being detected in 82%, in concentrations from 14.25 μg/kg to 98.80 μg/kg. Optimal conditions for mycotoxin production and fungal growth are frequently found in the crop fields as well as in store houses. Human exposure of such toxin can be controlled by pointed out such awareness and implemented the regulations.Keywords: Aflatoxin, HPLC, Pakistan, Peanuts, Punjab
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 22681771 Numerical Modeling of Steel-Composite Hybrid Tubes Subject to Static and Dynamic Loading
Authors: Y. S. Tai, M. Y. Huang, H. T. Hu
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The commercial finite element program LS-DYNA was employed to evaluate the response and energy absorbing capacity of cylindrical metal tubes that are externally wrapped with composite. The effects of composite wall thickness, loading conditions and fiber ply orientation were examined. The results demonstrate that a wrapped composite can be utilized effectively to enhance the crushing characteristics and energy absorbing capacity of the tubes. Increasing the thickness of the composite increases the mean force and the specific energy absorption under both static and dynamic crushing. The ply pattern affects the energy absorption capacity and the failure mode of the metal tube and the composite material property is also significant in determining energy absorption efficiency.
Keywords: fiber-reinforced metal tubes, energy absorption, axial crushing, impact loading.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 25241770 Sintering Properties of Mechanically Alloyed Ti-5Al-2.5Fe
Authors: Ridvan Yamanoglu, Erdinc Efendi, Ismail Daoud
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In this study, Ti-5Al-2.5Fe alloy was prepared by powder metallurgy. The elemental titanium, aluminum, and iron powders were mechanically alloyed for 10 h in a vacuum atmosphere. A stainless steel jar and stainless steel balls were used for mechanical alloying. The alloyed powders were then sintered by vacuum hot pressing at 950 °C for a soaking time of 30 minutes. Pure titanium was also sintered at the same conditions for comparison of mechanical properties and microstructural behavior. The samples were investigated by scanning electron microscopy, XRD analysis, and optical microscopy. Results showed that, after mechanical alloying, a homogeneous distribution of the elements was obtained, and desired a-b structure was determined. Ti-5Al-2.5Fe alloy was successfully produced, and the alloy showed enhanced mechanical properties compared to the commercial pure titanium.Keywords: Ti5Al2.5Fe, mechanical alloying, hot pressing, sintering.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 12711769 Impact of MAC Layer on the Performance of Routing Protocols in Mobile Ad hoc Networks
Authors: T.G. Basavaraju, Subir Kumar Sarkar, C Puttamadappa
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Mobile Ad hoc Networks is an autonomous system of mobile nodes connected by multi-hop wireless links without centralized infrastructure support. As mobile communication gains popularity, the need for suitable ad hoc routing protocols will continue to grow. Efficient dynamic routing is an important research challenge in such a network. Bandwidth constrained mobile devices use on-demand approach in their routing protocols because of its effectiveness and efficiency. Many researchers have conducted numerous simulations for comparing the performance of these protocols under varying conditions and constraints. Most of them are not aware of MAC Protocols, which will impact the relative performance of routing protocols considered in different network scenarios. In this paper we investigate the choice of MAC protocols affects the relative performance of ad hoc routing protocols under different scenarios. We have evaluated the performance of these protocols using NS2 simulations. Our results show that the performance of routing protocols of ad hoc networks will suffer when run over different MAC Layer protocols.Keywords: AODV, DSR, DSDV, MAC, MANETs, relativeperformance
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 26791768 An Approach in the Improvement of the Reliability of Impedance Relay
Authors: D. Ouahdi, R. Ladjeroud, I. Habi
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The distance protection mainly the impedance relay which is considered as the main protection for transmission lines can be subjected to impedance measurement error which is, mainly, due to the fault resistance and to the power fluctuation. Thus, the impedance relay may not operate for a short circuit at the far end of the protected line (case of the under reach) or operates for a fault beyond its protected zone (case of overreach). In this paper, an approach to fault detection by a distance protection, which distinguishes between the faulty conditions and the effect of overload operation mode, has been developed. This approach is based on the symmetrical components; mainly the negative sequence, and it is taking into account both the effect of fault resistance and the overload situation which both have an effect upon the reliability of the protection in terms of dependability for the former and security for the latter.
Keywords: Distance Protection, Fault Detection, negative sequence, overload, Transmission line.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 18411767 Optimal Distribution of Lift Gas in Gas Lifted Oil Field Using MPC and Unscented Kalman Filter
Authors: Roshan Sharma, Bjørn Glemmestad
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In gas lifted oil fields, the lift gas should be distributed optimally among the wells which share gas from a common source to maximize total oil production. One of the objectives of the paper is to show that a linear MPC consisting of a control objective and an economic objective can be used both as an optimizer and a controller for gas lifted systems. The MPC is based on linearized model of the oil field developed from first principles modeling. Simulation results show that the total oil production is increased by 3.4%. Difficulties in accurately measuring the bottom hole pressure using sensors in harsh operating conditions can be resolved by using an Unscented Kalman Filter (UKF) for estimation. In oil fields where input disturbance (total supply of gas) is not measured, UKF can also be used for disturbance estimation. Increased total oil production due to optimization leads to increased profit.
Keywords: gas lift, MPC, oil production, optimization, Unscented Kalman filter.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 26551766 Assessment of the Accuracy of Spalart-Allmaras Turbulence Model for Application in Turbulent Wall Jets
Authors: A. M. Tahsini
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The Spalart and Allmaras turbulence model has been implemented in a numerical code to study the compressible turbulent flows, which the system of governing equations is solved with a finite volume approach using a structured grid. The AUSM+ scheme is used to calculate the inviscid fluxes. Different benchmark problems have been computed to validate the implementation and numerical results are shown. A special Attention is paid to wall jet applications. In this study, the jet is submitted to various wall boundary conditions (adiabatic or uniform heat flux) in forced convection regime and both two-dimensional and axisymmetric wall jets are considered. The comparison between the numerical results and experimental data has given the validity of this turbulence model to study the turbulent wall jets especially in engineering applications.Keywords: Wall Jet, Heat transfer, Numerical Simulation, Spalart-Allmaras Turbulence model.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 27701765 Kinematic Optimal Design on a New Robotic Platform for Stair Climbing
Authors: Byung Hoon Seo, Hyun Gyu Kim, Tae Won Seo
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Stair climbing is one of critical issues for field robots to widen applicable areas. This paper presents optimal design on kinematic parameters of a new robotic platform for stair climbing. The robotic platform climbs various stairs by body flip locomotion with caterpillar type main platform. Kinematic parameters such as platform length, platform height, and caterpillar rotation speed are optimized to maximize stair climbing stability. Three types of stairs are used to simulate typical user conditions. The optimal design process is conducted based on Taguchi methodology, and resulting parameters with optimized objective function are presented. In near future, a prototype is assembled for real environment testing.Keywords: Stair climbing robot, Optimal design, Taguchi methodology, Caterpillar, Kinematic parameters.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 22991764 Mechanical and Chemical Reliability Assessment of Silica Optical Fibres
Authors: Irina Severin, M. Caramihai, K. Chung, G. Tasca, T. Park
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The current study has investigated the ageing phenomena of silica optical fibres in relation to water activity which might be accelerated when exposed to a supplementary energy, such as microwaves. A controlled stress by winding fibres onto accurate diameter mandrel was applied. Taking into account that normally a decrease in fibre strength is induced in time by chemical action of water, the effects of cumulative reagents such as: water, applied stress and supplementary energy (microwave) in some cases acted in the opposite manner. The microwave effect as a structural relaxation catalyst appears unexpected, even if the overall gain in fibre strength is not high, but the stress corrosion factor revealed significant increase in certain simulation conditions.Keywords: optical fibres, mechanical testing, aging, microwave, structural relaxation.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 16291763 A Preliminary Study for Design of Automatic Block Reallocation Algorithm with Genetic Algorithm Method in the Land Consolidation Projects
Authors: Tayfun Çay, Yaşar İnceyol, Abdurrahman Özbeyaz
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Land reallocation is one of the most important steps in land consolidation projects. Many different models were proposed for land reallocation in the literature such as Fuzzy Logic, block priority based land reallocation and Spatial Decision Support Systems. A model including four parts is considered for automatic block reallocation with genetic algorithm method in land consolidation projects. These stages are preparing data tables for a project land, determining conditions and constraints of land reallocation, designing command steps and logical flow chart of reallocation algorithm and finally writing program codes of Genetic Algorithm respectively. In this study, we designed the first three steps of the considered model comprising four steps.Keywords: Genetic algorithm, land consolidation, landholding, land reallocation.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 19071762 Simulation of Dynamics of a Permanent Magnet Linear Actuator
Authors: Ivan Yatchev, Ewen Ritchie
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Comparison of two approaches for the simulation of the dynamic behaviour of a permanent magnet linear actuator is presented. These are full coupled model, where the electromagnetic field, electric circuit and mechanical motion problems are solved simultaneously, and decoupled model, where first a set of static magnetic filed analysis is carried out and then the electric circuit and mechanical motion equations are solved employing bi-cubic spline approximations of the field analysis results. The results show that the proposed decoupled model is of satisfactory accuracy and gives more flexibility when the actuator response is required to be estimated for different external conditions, e.g. external circuit parameters or mechanical loads.Keywords: Coupled problems, dynamic models, finite elementanalysis, linear actuators, permanent magnets.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 27631761 Motion Control of an Autonomous Surface Vessel for Enhanced Situational Awareness
Authors: Igor Astrov, Mikhail Pikkov, Rein Paluoja
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This paper focuses on the critical components of the situational awareness (SA), the controls of position and orientation of an autonomous surface vessel (ASV). Moving of vessel into desired area in particular sea is a challenging but important task for ASVs to achieve high level of autonomy under adverse conditions. With the SA strategy, the approach motion by neural control of an initial stage of an ASV trajectory using neural network predictive controller and the circular motion by control of yaw moment in the final stage of trajectory were proposed. This control system has been demonstrated and evaluated by simulation of maritime maneuvers using software package Simulink. From the simulation results it can be seen that the fast SA of similar ASVs with economy in energy can be asserted during the maritime missions in search-and-rescue operations.
Keywords: Autonomous surface vessels, neurocontrollers, situational awareness.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 19761760 Density Wave Instability of Supercritical Kerosene in Active Cooling Channels of Scramjets
Authors: N. Wang, Y. Pan, J. Zhou, J. Lei, X. Z. Yang
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Experimental investigations were made on the instability of supercritical kerosene flowing in active cooling channels. Two approaches were used to control the pressure in the channel. One is the back-pressure valve while the other is the venturi. In both conditions, a kind of low-frequency oscillation of pressure and temperature is observed. And the oscillation periods are calculated. By comparison with the flow time, it is concluded that the instability occurred in active cooling channels is probably one kind of density wave instability. And its period has no relationship with the cooling channel geometry, nor the pressure, but only depends on the flow time of kerosene in active cooling channels. When the mass flow rate, density and pressure drop couple with each other, the density wave instability will appear.
Keywords: scramjets, active cooling, instability, density wave
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 15411759 Strip Decomposition Parallelization of Fast Direct Poisson Solver on a 3D Cartesian Staggered Grid
Authors: Minh Vuong Pham, Frédéric Plourde, Son Doan Kim
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A strip domain decomposition parallel algorithm for fast direct Poisson solver is presented on a 3D Cartesian staggered grid. The parallel algorithm follows the principles of sequential algorithm for fast direct Poisson solver. Both Dirichlet and Neumann boundary conditions are addressed. Several test cases are likewise addressed in order to shed light on accuracy and efficiency in the strip domain parallelization algorithm. Actually the current implementation shows a very high efficiency when dealing with a large grid mesh up to 3.6 * 109 under massive parallel approach, which explicitly demonstrates that the proposed algorithm is ready for massive parallel computing.
Keywords: Strip-decomposition, parallelization, fast directpoisson solver.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 20451758 Stack Ventilation for an Office Building with a Multi-Story Atrium
Authors: Karina Natali, Wei-Hwa Chiang
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This study examines the stack ventilation performance of an office building located in Taipei, Taiwan. Atriums in this building act as stacks that facilitate buoyancy-driven ventilation. Computational Fluid Dynamic (CFD) simulations are used to identify interior airflow patterns, and then used these patterns to assess the building’s heat expulsion efficiency. Ambient temperatures of 20°C were adopted as the typical seasonal spring temperature range in Taipei. Further, “zero-wind” conditions are established to ensure simulation results reflected only the buoyancy effect. After checking results against neutral pressure level (NPL) level, airflow, air velocity, and indoor temperature stratification, the lower stack is modified to reduce the NPL in order to remove heat accumulated on the top floor.
Keywords: Natural ventilation, side outlet, stack effect, thermal comfort.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 20041757 A Practical Construction Technique to Enhance the Performance of Rock Bolts in Tunnels
Authors: O. Chaudhari, A. N. Ghafar, G. Zirgulis, M. Mousavi, T. Ellison, S. Pousette, P. Fontana
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In Swedish tunnel construction, a critical issue that has been repeatedly acknowledged is corrosion and, consequently, failure of the rock bolts in rock support systems. The defective installation of rock bolts results in the formation of cavities in the cement mortar that is regularly used to fill the area under the dome plates. These voids allow for water-ingress to the rock bolt assembly, which results in corrosion of rock bolt components and eventually failure. In addition, the current installation technique consists of several manual steps with intense labor works that are usually done in uncomfortable and exhausting conditions, e.g., under the roof of the tunnels. Such intense tasks also lead to a considerable waste of materials and execution errors. Moreover, adequate quality control of the execution is hardly possible with the current technique. To overcome these issues, a non-shrinking/expansive cement-based mortar filled in the paper packaging has been developed in this study which properly fills the area under the dome plates without or with the least remaining cavities, ultimately that diminishes the potential of corrosion. This article summarizes the development process and the experimental evaluation of this technique for the installation of rock bolts. In the development process, the cementitious mortar was first developed using specific cement and shrinkage reducing/expansive additives. The mechanical and flow properties of the mortar were then evaluated using compressive strength, density, and slump flow measurement methods. In addition, isothermal calorimetry and shrinkage/expansion measurements were used to elucidate the hydration and durability attributes of the mortar. After obtaining the desired properties in both fresh and hardened conditions, the developed dry mortar was filled in specific permeable paper packaging and then submerged in water bath for specific intervals before the installation. The tests were enhanced progressively by optimizing different parameters such as shape and size of the packaging, characteristics of the paper used, immersion time in water and even some minor characteristics of the mortar. Finally, the developed prototype was tested in a lab-scale rock bolt assembly with various angles to analyze the efficiency of the method in real life scenario. The results showed that the new technique improves the performance of the rock bolts by reducing the material wastage, improving environmental performance, facilitating and accelerating the labor works, and finally enhancing the durability of the whole system. Accordingly, this approach provides an efficient alternative for the traditional way of tunnel bolt installation with considerable advantages for the Swedish tunneling industry.
Keywords: corrosion, durability, mortar, rock bolt
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 4201756 ANN Modeling for Cadmium Biosorption from Potable Water Using a Packed-Bed Column Process
Authors: Dariush Jafari, Seyed Ali Jafari
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The recommended limit for cadmium concentration in potable water is less than 0.005 mg/L. A continuous biosorption process using indigenous red seaweed, Gracilaria corticata, was performed to remove cadmium from the potable water. The process was conducted under fixed conditions and the breakthrough curves were achieved for three consecutive sorption-desorption cycles. A modeling based on Artificial Neural Network (ANN) was employed to fit the experimental breakthrough data. In addition, a simplified semi empirical model, Thomas, was employed for this purpose. It was found that ANN well described the experimental data (R2>0.99) while the Thomas prediction were a bit less successful with R2>0.97. The adjusted design parameters using the nonlinear form of Thomas model was in a good agreement with the experimentally obtained ones. The results approve the capability of ANN to predict the cadmium concentration in potable water.
Keywords: ANN, biosorption, cadmium, packed-bed, potable water.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 21301755 The National Security Assurance of the Republic of Kazakhstan
Authors: Sholpan Zhandossova, Erden Ordabek, Yelbolsyn Nazarov
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the article analyzes the national security as a scientific and practical problem, characterized by the state's political institutions to ensure effective action to maintain optimal conditions for the existence and development of the individual and society. National security, as a category of political science reflects the relationship between the security to the nation, including public relations and social consciousness, social institutions and their activities, ensuring the realization of national interests in a particular historical situation. In national security are three security levels: individual, society and state. Their role and place determined by the nature of social relations, political systems, the presence of internal and external threats. In terms of content in the concept of national security is taken to provide political, economic, military, environmental, information security and safety of the cultural development of the nation.
Keywords: Kazakhstan, national security, religious extremism
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 19561754 Effects of the Wavy Surface on Free Convection-Radiation along an Inclined Plate
Authors: M. Si Abdallah, B. Zeghmati
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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.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 23311753 Gravitational Search Algorithm (GSA) Optimized SSSC Based Facts Controller to Improve Power System Oscillation Stability
Authors: Gayadhar Panda, P. K. Rautraya
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Damping of inter-area electromechanical oscillations is one of the major challenges to the electric power system operators. This paper presents Gravitational Search Algorithm (GSA) for tuning Static Synchronous Series Compensator (SSSC) based damping controller to improve power system oscillation stability. In the proposed algorithm, the searcher agents are a collection of masses which interact with each other based on the Newtonian gravity and the laws of motion. The effectiveness of the scheme in damping power system oscillations during system faults at different loading conditions is demonstrated through time-domain simulation.
Keywords: FACTS, Damping controller design, Gravitational search algorithm (GSA), Power system oscillations, Single-machine infinite Bus power system, SSSC.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 23561752 Beating Phenomenon of Multi-Harmonics Defect Frequencies in a Rolling Element Bearing: Case Study from Water Pumping Station
Authors: Fathi N. Mayoof
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Rolling element bearings are widely used in industry, especially where high load capacity is required. The diagnosis of their conditions is essential matter for downtime reduction and saving cost of maintenance. Therefore, an intensive analysis of frequency spectrum of their faults must be carried out in order to determine the main reason of the fault. This paper focus on a beating phenomena observed in the waveform (time domain) of a cylindrical rolling element bearing. The beating frequencies were not related to any sources nearby the machine nor any other malfunctions (unbalance, misalignment ...etc). More investigation on the spike energy and the frequency spectrum indicated a problem with races of the bearing. Multi-harmonics of the fundamental defects frequencies were observed. Two of them were close to each other in magnitude those were the source of the beating phenomena.Keywords: Bearing, beating, spike energy, vibration.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 41711751 Bandwidth Allocation for ABR Service in Cellular Networks
Authors: Khaja Kamaluddin, Muhammed Yousoof
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Available Bit Rate Service (ABR) is the lower priority service and the better service for the transmission of data. On wireline ATM networks ABR source is always getting the feedback from switches about increase or decrease of bandwidth according to the changing network conditions and minimum bandwidth is guaranteed. In wireless networks guaranteeing the minimum bandwidth is really a challenging task as the source is always in mobile and traveling from one cell to another cell. Re establishment of virtual circuits from start to end every time causes the delay in transmission. In our proposed solution we proposed the mechanism to provide more available bandwidth to the ABR source by re-usage of part of old Virtual Channels and establishing the new ones. We want the ABR source to transmit the data continuously (non-stop) inorderto avoid the delay. In worst case scenario at least minimum bandwidth is to be allocated. In order to keep the data flow continuously, priority is given to the handoff ABR call against new ABR call.Keywords: Bandwidth allocation, Virtual Channel (VC), CBR, ABR, MCR and QOS.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 16001750 Comparative Life Cycle Assessment of Rapeseed Oil and Biodiesel from Winter Rape Produced in Romania
Authors: Raluca-Cristina Buţurcă, CarlesM.Gasol, Xavier Gabarrell, Dan Scarpete
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The environmental performance of rapeseed oil (RO) and rapeseed methyl ester(RME) from winter rape as fuels produced in Romanian agroclimate is analyzed in this paper. The proposed methodology is life cycle assessment (LCA) and takes into consideration the influence of grain production and agroclimatic conditions. This study shows favorable results first for RO and then for RME. When compared to diesel fuel, both studied biofuels show better results in the following impact categories: Abiotic depletion potential (ADP), Ozone layer depletion (ODP) and Photochemical ozone creation potential (POCP).Furthermore, the environmental performance of the two biofuels studied can be improved by changing the type of fertilizer used and also by using biofuels instead of diesel in the field works.
Keywords: Biodiesel, life cycle assessment, rapeseed oil.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 25501749 Minimizing of Target Localization Error using Multi-robot System and Particle Filters
Authors: Jana Puchyova
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In recent years a number of applications with multirobot systems (MRS) is growing in various areas. But their design is in practice often difficult and algorithms are proposed for the theoretical background and do not consider errors and noise in real conditions, so they are not usable in real environment. These errors are visible also in task of target localization enough, when robots try to find and estimate the position of the target by the sensors. Localization of target is possible also with one robot but as it was examined target finding and localization with group of mobile robots can estimate the target position more accurately and faster. The accuracy of target position estimation is made by cooperation of MRS and particle filtering. Advantage of usage the MRS with particle filtering was tested on task of fixed target localization by group of mobile robots.Keywords: Multi-robot system, particle filter, position estimation, target localization.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 15671748 Effects of Winter and Spring Sowing on Yield Components of Safflower Genotypes
Authors: Rahim Ada
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The research was conducted with three replications as “Randomized Block Design” in Konya-Turkey ecological conditions. In the study, 16 of promising safflower lines (A8, E1, F4, F6, G16, H14, I1), and 1 cultivar (Dinçer) were evaluated in 2008-09 growing season. Some of the yield components such as plant height (cm), first branch height (cm), number of branches per plant, 1000 seed weight (g), seed yield (kg ha-1), oil content (%), oil yield (kg ha-1) were determined. Winter sowing showed higher values than spring sowing. The highest values were taken from Dinçer for plant height (86.7 cm), E1 (37.5 cm) for first branch height, F6 for number of branch (11.6 per plant), I1 for number of head (24.9 per plant), A8 for 1000 seed weight (51.75 g), Dinçer for seed yield (2927.1 kg ha-1), oil content (28.79 %) and also for oil yield (87.44 kg ha-1) respectively.Keywords: Oil yield, Safflower, Sowing time, Yield components
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2481