bluuebunny/crossref_metadata_2025 huggingface dataset:
Corrosión de armaduras en los hormigones armados y pretensados, II
Authors: Calleja J.
Published: August 2015

Dentro del capítulo general de la «durabilidad» o resistencia química en el tiempo de los conglomerados hidráulicos (morteros y hormigones armados y pretensados), el apartado relativo a la «corrosión» de las armaduras ocupa un lugar preponderante por su importancia técnica y económica.
Esta importancia va siendo reconocida cada día más, a pesar de ser (o de haber sido) el de la corrosión uno de los temas menos familiares en el ámbito de la construcción. La razón estriba en la fuerza de los hechos, y se manifiesta con claridad en las tareas encomendadas y en los problemas presentados a los laboratorios de investigación y ensayos de materiales.
La corrosión es un fenómeno fisicoquímico que cae dentro del dominio de la ELECTROQUÍMICA y que debe estudiarse y enjuiciarse con arreglo a las leyes fundamentales de esta disciplina. Lo mismo cabe decir por lo que respecta a los métodos de «protección» contra la corrosión.
La corrosión es un «riesgo» aleatorio que se corre y contra el que hay que prevenirse mediante un «seguro», representado por dichas medidas de protección.
El remedio «más fácil» desde un punto de vista «técnico», y «más barato» desde un punto de vista «económico», es siempre de carácter «preventivo» antes que «curativo», es decir, es el tomado ya en la etapa de proyecto de la obra o estructura de que se trate.
En el caso del hormigón, la mejor protección de las armaduras la da, en primer lugar, la aplicación de un «código de buena práctica» a la elaboración del material y a la ejecución de la obra, y, en segundo lugar, la observancia de los más elementales principios de la Electroquímica en el aspecto de la corrosión.
La utilización de aditivos acelerantes de fraguado y endurecimiento, con naturaleza «clorurada» y el estado de «tensión» de las armaduras son aspectos que merecen especial consideración, así como las posibles acciones electroquímicas debidas a «corrientes vagabundas» a través de las armaduras de la estructura.
Casa de la juventud, en Stuttgart, Alemania
Authors: Ellsässer Karl
Published: August 2015

El conjunto construido consta de tres edificios unidos entre sí:
El edificio principal alberga, en el semisótano, los talleres de carpintería y metalistería, laboratorio fotográfico, taller de cerámica, cuartos de las instalaciones, etc.; en la planta baja, una serie de salas de juegos, etc., el cuarto del jefe de la juventud, y vivienda del director; y en la planta alta, la biblioteca, un local para la práctica de labores manuales, etc.
El edificio de la gran sala colectiva aloja, en su nivel inferior, un salón cafetería-bar, comedor, sala de dibujo; y en la primera planta, la sala para múltiples usos —proyección de películas, reuniones, etc.— con capacidad de 180 asientos.
Finalmente el tercer edificio alberga la sala de ping-pong y un local para guardar bicicletas.
La construcción es diáfana, agradable y está concebida y realizada con esmero, de acuerdo con las directrices y materiales más modernos.
Laboratorios FHER, en Malgrat (Barcelona)
Authors: Barba Corsini F. J. , Minto Neil Ch.
Published: August 2015

Este edificio, que tiene planta rectangular, consta de dos alturas, destinadas a oficinas y Centro de investigación. En la planta baja hay un amplio vestíbulo de acceso, del cual parte un paso central con dependencias a ambos lados (laboratorios, locales anexos, etc.). En la primera planta, que presenta una distribución similar, están situados a ambos lados del pasillo central, los despachos del director y del ingeniero; una sala de juntas; oficinas de contabilidad, caja, etc. El edificio está rodeado de jardín y, tanto en su tratamiento exterior como en la distribución y decoración interior, se observa un extraordinario cuidado y una gran sinceridad de expresión.
La industrialización de las construcciones agropecuarias en Checoslovaquia
Authors: Aguirre de Yraola Fernando
Published: August 2015

El presente artículo informa de la aplicación de las nuevas técnicas industrializadas, en especial las cerámicas, a la resolución de problemas específicos que se plantean en la prefabricación de construcciones agrícolas.
Las soluciones adoptadas por los checos constituyen un exponente de la utilidad que para la técnica supone la investigación.
Captadores a cuerda vibrante: su fundamento y aplicaciones
Authors: Fuentes Alberto
Published: August 2015

La reciente adquisición por el Instituto Eduardo Torroja de un equipo de medida para captadores a cuerda vibrante nos ha sugerido la publicación del presente artículo, en el cual se resumen la teoría y aplicaciones de tales captadores, cuyo uso se está extendiendo mucho en los últimos años, no sólo en las grandes obras como presas y puentes, sino también en los laboratorios de la construcción.
Teatro Playhouse, en Nottingham (Inglaterra)
Authors: Peter Moro & Partners Arquitectos
Published: August 2015

En su composición volumétrica destacan claramente los siguientes volúmenes: el del hall de entrada y vestíbulo; el del auditorio, organizado en cuatro niveles; el del escenario y parte posterior del mismo; y el de un cuerpo de edificación saliente, que aloja un restaurante y cafetería.
Es de resaltar en este teatro, el acierto de los arquitectos en la elección y combinación de las texturas de los materiales empleados, la sinceridad expresiva del sistema estructural adoptado y la línea avanzada de los relieves y ornato interior de vestíbulos y sala.
Penitenciaría federal de Marion. Illinois (U. S. A.)
Authors: Hellmuth, Obata y Kassabaum Arquitectos
Published: August 2015

Esta penitenciaría Federal ha sido construida para albergar 600 reclusos, pero con la posibilidad de poder ampliar fácilmente su capacidad hasta 1.000.
Al conjunto, que presenta una distribución general radial, se accede a través del edificio de la Administración situado a la entrada, fuera de la doble cerca metálica de seguridad.
A través del corredor principal, se llega al núcleo central, del que parten otros tres corredores; el de la derecha consta de cinco unidades constructivas, que contienen las celdas de los reclusos y una unidad dormitorio, la biblioteca, el auditorio-gimnasio y la escuela.
Al corredor del fondo dan otras unidades con celdas, la unidad de admisión, hospital, etc.; y al corredor de la izquierda: la capilla, el comedor de reclusos, las zonas de servicio, cocinas, lavandería, etc.
El edificio es noble y de calidad, de acuerdo con las modernas directrices en este tipo de construcciones.
Casa-estudio núm. 25, de Arts & Architecture, en Los Ángeles, (U. S. A.)
Authors: Killingsworth – Brady - Smith Arquitectos and Associate
Published: August 2015

Desarrollada en dos plantas aloja, en la baja, un amplio vestíbulo abierto, la zona de vivir diurna, comedor, cocina, servicios y garaje. Y en la planta superior, un. Estudio— convertible en caso de necesidad en dormitorio—, dormitorio principal, un segundo dormitorio y dos baños. La casa es notable en muchos aspectos y marca una pauta interesante a seguir.
Puente sobre el tramo inferior del Elba, Hamburgo
Authors: Aschenberg H. , Freudenberg G.
Published: August 2015

Este puente, que une las autopistas Hamburgo-Hannover y Hamburgo-Lübeck, tiene 411 m de longitud, 30,74 m de anchura y 5 tramos.
El entramado de rigidez del tramo central, de 173 m de luz, que está suspendido por cables que se apoyan en dos torres, de 53 m de altura respecto a la calzada, tiene la sección transversal formada por un cajón central y dos vigas laterales de alma llena con un canto uniforme de 3 m. Dichas torres soportan dos paquetes de cables que se apoyan en sillas montadas a diferente altura, estando estos apoyos organizados de forma que permitan los movimientos provocados por las diferencias de temperatura sin originar deformaciones abusivas ni momentos secundarios.
La mayor parte de los elementos han sido prefabricados en taller y transportados por vía fluvial. La construcción del tramo central se ha realizado por voladizos sucesivos hasta llegar al cierre en la clave.
La documentación al servicio de la industria de la construcción
Authors: Comyn Antonio
Published: August 2015

Una de las notas más sobresalientes de la época en que vivimos es el marcado desvelo mundial por las técnicas de la Gerencia de Empresas y de la Organización Científica del Trabajo. En todas las naciones y ramas de la Industria los temas de Estudio de mercados, Productividad, Información Técnica y Documentación, Mecanización Administrativa, Control de la Calidad, Relaciones humanas, etc., son motivo continuo para la formación de Empresas Consultoras y para la impresión de millares de libros, artículos de revistas y folletos.
Ampliación del puerto de Miami, (U.S.A.)
Authors: Volkert David
Published: August 2015

Como no se disponía de espacio en las zonas adyacentes al puerto en explotación, y la bahía tenía una serie de Islotes propicios para hacer un relleno, surgió la idea de realizarlo, en tomo a aquéllos, con planta rectangular, aprovechando los muros perimetrales para formar los muelles de atraque.
Por hallarse este relleno separado de la costa, se ha construido un paso superior, sobre el agua, para el tráfico de vehículos de ruedas neumáticas, y una plataforma paralela destinada al tráfico ferroviario.
Dada la gran longitud del paso y la necesidad de asegurar la navegación costera, la parte central del paso, correspondiente al canal, se salva con un tramo basculante.
Para conseguir aguas profundas en los muelles se han realizado importantes operaciones de dragado e hinca de tablestacas.
YTONG - 0,65 C.D.U.: 69.022.3 D. I. T. n. 11 Elementos para muros; Elements for walls
Authors: Nadal J.
Published: August 2015

No disponible
Tracing Structures in Networks to Capture its Organization
Authors: Raya-Díaz Karina , Gaxiola-Pacheco Carelia , Castañón-Puga Manuel
Published: August 2015

This article analyzes the central nervous system as a dynamic complex system, focusing on the micro-interactions that allow neurons to become part of a network. The purpose of this analysis is to identify organizational levels generated in neural networks when a fault occurs and how topological structures are created during the information transmission, as in computer networks. The calculation of clustering coefficient was using as a method to observe the association of each node of the network. A dendrogram was created to reflect the changes in the interactions of the links of nodes.
Towards Transparent Throughput Elasticity for IaaS Cloud Storage
Authors: Nicolae Bogdan , Riteau Pierre , Keahey Kate
Published: August 2015

Storage elasticity on IaaS clouds is a crucial feature in the age of data-intensive computing, especially when considering fluctuations of I/O throughput. This paper provides a transparent solution that automatically boosts I/O bandwidth during peaks for underlying virtual disks, effectively avoiding over-provisioning without performance loss. The authors' proposal relies on the idea of leveraging short-lived virtual disks of better performance characteristics (and thus more expensive) to act during peaks as a caching layer for the persistent virtual disks where the application data is stored. Furthermore, they introduce a performance and cost prediction methodology that can be used both independently to estimate in advance what trade-off between performance and cost is possible, as well as an optimization technique that enables better cache size selection to meet the desired performance level with minimal cost. The authors demonstrate the benefits of their proposal both for microbenchmarks and for two real-life applications using large-scale experiments.
Assessment of Fluid Intelligence Utilizing a Computer Simulated Game
Authors: Buford Charles Colby , O'Leary Brian J.
Published: August 2015

Measurement of General Mental Ability (GMA) using computer mediated simulations (CMS) may provide a new method of assessment. CMS used for assessments of GMA may be strongly affected by a participant's prior experience, and the predictive utility of CMS for assessment of GMA is largely unexplored. In this experiment, an existing computer video game was modified to function as an assessment of Fluid Intelligence (Gf) while controlling for participants' prior experience with CMS. Results indicated a positive relationship between tests of Fluid Intelligence (Gf) and game performance (r = .44 - 46), a weaker relationship between game performance and Crystallized Intelligence (Gc) (r = .27), no significant relationship to g, and no significant moderating effect for participants' prior experience upon any of these relationships. Based on these findings, CMS appear to hold promise as a new assessment tool for factors of GMA.
Monster Mischief
Authors: Godwin Karrie E. , Lomas Derek , Koedinger Ken R. , Fisher Anna V.
Published: August 2015

Selective sustained attention, or the ability to allocate perceptual and mental resources to a single object or event, is an important cognitive ability widely assumed to be required for learning. Assessing young children's selective sustained attention is challenging due to the limited number of sensitive and developmentally appropriate performance-based measures. Furthermore, administration of existing assessments is difficult, as children's engagement with such tasks wanes quickly. One potential solution is to provide assessments within an engaging environment, such as a video game. This paper reports the design and psychometric validation of a video game (Monster Mischief) designed to assess selective sustained attention in preschool children. In a randomized controlled trial, the authors demonstrate that Monster Mischief is significantly correlated with an existing measure of selective sustained attention (rs = 0.52), and more motivating for young children as almost 3 times more children preferred Monster Mischief to the existing measure.
A New Fuzzy-Based Approach for Anonymity Quantification in E-Services
Authors: Hammami Wiem , Souissi Ilhem , Ben Said Lamjed
Published: August 2015

In online services, making anonymous transactions is a crucial need in order to ensure the user's trust towards a particular service. In this context, anonymity quantification is required to provide at which level the e-service respects the user privacy regarding the link between his/her identity and actions. Most of the existing researches are limited to the anonymity quantification in a static way and based, mainly, on the user's set size. In this paper, the authors propose a new multi-agent based approach for anonymity quantification in e-services considering dynamic and mobile environment's characteristics. The authors' quantification is based on the fuzzy logic. It is based not only on the anonymity set size, which is always known in advance, but also on a set of other criteria such as the number of users and the priori and posteriori knowledge about internal and external attackers of an e-service. The carried out experimentations show competitive and better results when compared to other recently proposed anonymity quantification.
Harnessing New Product Development Processes through Strategic Thinking Initiatives
Authors: Kazmi S. Asiya Z. , Naarananoja Marja , Kytola Juha
Published: August 2015

This paper evaluates the role of strategic thinking to support multinational organization's new product development initiatives. Furthermore, it emphases how organizational commitment to empower its work team's leadership capability can be highlighted in the form of weak areas through specialized survey. The research outcomes highlighted the gaps in the subject organization's NPD initiatives through drawing attention to the grey areas present in the overall corporate strategic leadership environment of its three targeted work locations (i.e. Finland, the UK, and -Norway). Such areas include the potential of the company's internal communication system, data collection and record keeping capability, management's approach to the potential of new idea generation and employees' empowerment. The referred areas are directly linked to the subject company's new product development strategy, corporate initiatives and operational growth.
A Robust Data Envelopment Analysis Method with Bounded Data for Ranking Operations Strategies
Authors: Kaviani Mohamad Amin , Abbasi Mehdi
Published: August 2015

This paper introduces a new robust data envelopment analysis (RDEA) approach for analyzing and ranking the organizations' operations strategies. In the proposed RDEA method, pessimistic and optimistic efficiencies of decision making units (DMUs) obtained from the robust counterpart of the envelopment form and the optimistic counterpart of the multiplier form of DEA are introduced. The inputs and outputs data are assumed to be bounded data (interval numbers) in the proposed models. A case study in the cement industry is presented to demonstrate the applicability of the proposed RDEA approach. The results obtained from the authors' proposed RDEA approach is more robust and their method provides a more complete ranking of the DMUs compared to conventional Likert-based DEA model.
New Swarm Intelligence Technique of Artificial Social Cockroaches for Suspicious Person Detection Using N-Gram Pixel with Visual Result Mining
Authors: Bouarara Hadj Ahmed , Hamou Reda Mohamed , Amine Abdelmalek
Published: August 2015

In the last decade, surveillance camera technology has become widely practiced in public and private places to ensure the safety of individuals. Merely, face to limits of violation the private life of people and the inability to identify malicious persons that hid their faces, finding a new policy of surveillance video has become compulsory. The authors' work deals on the development of a suspicious person detection system using a new insect behaviour algorithm called artificial social cockroaches ASC based on a new image representation method (n-gram pixel). It has as input a set of artificial cockroaches (human images) to classify them (hide) into shelters (classes) suspicious or normal depending on a set of aggregation rules (shelter darkness, congener's attraction and security quality). Their experiments were performed on a modified MuHAVi dataset and using the validation measures (recall, precision, f-measure, entropy and accuracy), in order to show the benefit derived from using such approach compared to the result of classical algorithms (KNN and C4.5). Finally, a visualisation step was achieved to see the results in graphical form with more realism for the purpose to help policeman, security associations and justice in their investigation.
Adopting Balance Score Card in Higher Education
Authors: Baporikar Neeta
Published: August 2015

Education enhances knowledge base of the nation. It plays a vital role in development. Emerging global trends, new economic challenges and rapid growth of information technology has enlarged the focus on education making analyzing and assessing simultaneously several areas of performance essential and crucial. If Balance Score Card used by organizations to achieve excellence, is adopted in higher education by universities and higher educational institutions academic excellence could be attained. In addition, it can help them to utilize intangible assets more efficiently, ensure future growth and link long-term strategic planning to short-term, tactical actions. Adopting it would also provide a strong linkage between financial and operational measures, internal processes improvement and innovation activities. Thus, through in-depth literature review and grounded theory the aim of this paper is to give an overview of Balance Score Card, discuss its adoption in higher education by universities and higher education institutions.
A dsPIC Microcontroller Based System Identification of Positive Output Buck Boost Converter for Module Mismatch Application
Authors: Hussain M.N.M. , Omar Ahmad Maliki , Ibrahim Intan Rahayu , Daud Kamarulazhar
Published: August 2015

An identification system of multiple-input single-output (MISO) model is developed in controlling dsPIC microcontroller of positive output buck-boost (POBB) converters for module mismatch condition of photovoltaic (PV) system. In particular, the possibility of the scheme is to resolve the mismatch losses from the PV module either during shading or mismatch module occurrences. The MPPT algorithm is simplified by identification approach of indirect incorporated with a simple incremental direct method to form a combined direct and indirect (CoDId) algorithms. Irregular consumption of solar irradiation on a PV module shall step-up or step down the voltage regarding to the desired DC output voltage of POBB converter. This optimized algorithm will ensure that the PV module to kept at maximum power point (MPP), preventing power loss during module mismatch incident in PV module especially during partial shading condition. The simulation and laboratory results for PV module of polycrystalline Mitsubishi PV-AE125MF5N indicate that the proposed model and development of PV system architecture performs well, while the efficiency up to 97.7% at critical of low solar irradiance level. The controlling signal is based on low-cost embedded microcontroller of dsPIC30F Digital Signal Control (DSC).
The Impacts of the Disturbances for the Hybrid Fuzzy-Fuzzy Controller Applied to Induction Motor Drive
Authors: Magzoub Muawia A. , Saad Nordin B. , Ibrahim Rosdiazli B.
Published: August 2015

The study of the effects of an internally and externally caused disturbances for the advanced hybrid fuzzy-fuzzy controller (HFFC) scheme in order to gain control over the speed of an induction motor’s (IM) variable speed drive (VSD) is the main objective of this research paper The HFFC works on the principle of gaining control over the rotor speed during steady-state stage using fuzzy stator current magnitude controller whereas, during an accelerate-decelerate stage by utilising a fuzzy frequency controller, to overcome the disadvantage of field oriented control (FOC) method. The design of a scalar controller involves two aspects of FOC i.e current and frequency. Hence, the performance of a controller has been observed with a series of tests which yielded a controller which is more effective, consistent and insensitive to the parameter variation for the motor and system strength to noise and load disturbances.
Design and Analysis of a Digital Controller for Boost Converter with Renewable Energy Sources for Domestic DC Load
Authors: Ibrahim Oladimeji , Yahaya N.Z. , Saad N. , Ahmed K.Y.
Published: August 2015

Renewable energy sources like solar PV produces DC voltage which is converted to AC before connecting to domestic grid network. The conversion process from DC to AC and back to DC at load end introduce additional losses in the system. With increasing availability of modern DC loads and growing use of renewable energy, the use of DC network for domestic load supply is on increase in order to reduce energy conversion losses. Presented in this paper is a fast transient digital controller for DC-DC boost converter with energy source from solar PV for domestic DC loads like lightings. The boost converter was model as both steady and dynamic state. Digital controllers were designed using both digital redesign approach and direct digital redesign approach. The system demonstrated fast transient response that is essential for tightly regulated output voltage from constantly varying renewable energy generations.
Performance Development of Space Vector Pulse Width Modulation for Induction Motor Drive Using Artificial Intelligence
Authors: Abd Ali Jamal , Hannan M.A. , Mohamed Azah , Shareef Hussein , Hussein Mutlag Ammar
Published: August 2015

Space vector pulse width modulation (SVPWM) technique is an advanced computation-intensive PWM method. It is the best among all PWM techniques for three-phase induction motor (TIM) drive applications because of its superior performance characteristics. In this paper, the use of artificial neural network (ANN) based SVPWM technique avoids the computational complex used in conventional SVM implementation. An ANN scheme structure is suggested to identify and approximate the conventional SVPWM for decrease the computational problem. Moreover, proportional-integral (PI) controller tuning is achieved using a particle swarm optimization (PSO) algorithm to improve the TIM speed controller’s response performance. By designing an appropriate PSO algorithm, kp and ki of the PI speed controller parameters are tuned for TIM to attain the best parameter values.
Performance Comparison of VSI Switches Faults Analysis Using STFT and S Transform
Authors: Manap M. , Abdullah A.R. , Saharuddin N.Z. , Abidullah N.A. , Ahmad Nur Sumayyah , Jopri M.H.
Published: August 2015

Switches fault in power converter has become compelling issues over the years. To reduce cost and maintenance downtime, a good fault detection technique is an essential. In this paper, the performance of STFT and S transform techniques are analysed and compared for voltage source inverter (VSI) switches faults. The signal from phase current is represented in jointly time-frequency representation (TFR) to estimate signal parameters and characteristics. Then, the degree of accuracy for both STFT and S transform are determined by the lowest value of mean absolute percentage error (MAPE). The results demonstrate that S transform gives better accuracy compare to STFT and is suitable for VSI switches faults detection and identification system.
DC Loads Matching Technique as an Alternative to AC Inverter in Residential Solar System Application Evaluation and Comparison
Authors: Sabry Ahmad H. , Wan Hasan Wan Zuha , Zainal Mohd , Amran Mohd , Shafie Suhaidi B.
Published: August 2015

since PV inverter cost and performance in residential Solar System Application is a controversial subject, it always needs to be researched to encounter the challenges of cost competitions especially with environmentally polluted fossil fuel energy expense. This research proposes a fundamentally novel solutions for utilizing the unavoidable solar system losses by the hypothesis of dispensing the power converters in domestic application of home solar system. This hypotheses based on matching methods between the energy source, the Battery bank, and the load, home appliances. Since the energy source is a direct current DC supply, this matching process would be via evaluating of the normal alternative current AC appliances and compatibility range to be switched on DC supply, the operation of the appliances evaluated individually with DC supply either by direct coupling or with simple modification, the analysis of the data have been accumulated in terms of efficiency. Individually, appliances were classified according to different aspects in such a way that shows its compatibility range with the DC power supply. A comparison results for each classified appliances have been done for both operation conditions AC and DC. The efficiency of a relatively good quality Inverter would be referred to see what gain would be obtained from switching to DC supply-load matching when eliminating of AC Inverter from the system. A sequence of processes have been carried out on home appliances individually in terms of its electrical and electronic composition towards best system performance and reasonable cost. MATLAB Simulink has been used as a simulation program. The results shows; great utilization of the home solar system losses, cost and faults probability reduction, high efficiency, and more reliable system.
Performance Analysis of Brushless DC Motor Drive for Air Conditioner
Authors: bin Abu Hassan Mohd Arif , bin Abdullah Abdul Rahim , bt Bahari Nurhazilina , Mohd Sabri Muhammad Ihsan
Published: August 2015

This paper presents an efficiency comparison and verification of two types of Brushless DC (BLDC) motors and drives combination. The trapezoidal BLDC motor is excited by trapezoidal drive and sinusoidal BLDC motor is excited by sinusoidal drive. In air conditioner fan motor system, the sinusoidal type of BLDC motor with sinusoidal drive is applied. However, the DC link voltage of the motor is high and thus demands for high power consumption. Furthermore, the sinusoidal drive use vector control which is complicated to be implemented and make the driver high cost. Therefore, further improvement in energy consumption and drive system is required by develop combination of trapezoidal BLDC motor with trapezoidal drive. Thus, these two combination motors and drives required for efficiency comparison. The motors drives are simulated by using MATLAB and then their efficiencies are measured. At the end of this paper, the results show that the trapezoidal BLDC motor with trapezoidal drive offers higher efficiency compared to sinusoidal BLDC motor with vector control drive. It indicates that the developed drive system is considerable to be applied in the air conditioner fan motor system.
Loading Performances of Low-Power Low-Speed Single-Phase Induction Generator with Energy Saving Lamps
Authors: Santoso Hari , Hasanah Rini Nur , Wardana I.N.G. , Mismail Budiono
Published: August 2015

The increasing use of energy saving lamps provides additional benefits to the application of low-power low-speed self-excited induction generators resulted from capacitor motor modification. Reactive power requirement of the generator can be provided from the capacitive nature of the lamps, while at the same time it is delivering active power to loads. Any loading change will automatically increase or reduce reactive power supply to generator. Results of experiments show that low-power low-speed single-phase self-excited induction generator is more robust and suitable for this kind of loads. Generator does not lose its voltage when experiencing abrupt change of loads. This robustness makes the generator suitable for the use in low-capacity hydropower generation in remote areas being commonly not covered by national electricity grid.
Improved Design of Three Phase Hybrid Excitation Flux Switching Motor with Segmental Rotor
Authors: Sulaiman Erwan , Ali Hassan , Aizat Mubin , Aizat Zhafir
Published: August 2015

This paper presents the new design of Hybrid Excitation Flux Switching Motor (HEFSM) using segmental rotor structure. HEFSMs are those that consist all the excitation flux sources at their stator with robust rotor structure. The rotor is designed as segmental due to the reason that segmental rotor has ability to yield the magnetic path for conveying the field flux to nearby stator armature coil with respect to the rotation of the rotor. This design gives the clear advantage of shorter end winding compared to the toothed rotor as there is no overlap winding between field excitation coil (FEC) and armature coil. In this paper the initial design of HEFSM with segmental rotor has been improved by changing segment span, FEC slot area and armature slot area until maximum torque and power of 33.633 Nm and 8.17 KW respectively have been achieved. Moreover coil test analysis, induced voltage, cogging torque, magnetic flux characteristics, torque vs. field current density and torque vs. power speed characteristics are examined on the basis of 2-D finite element analysis (FEA).
A Performance Comparison of Three Micro-Sized Blade Rotor Designs for Malaysia Wind Speed Condition
Authors: Rosmin Norzanah , Rahman N.A. , Mustaamal A.H.
Published: August 2015

Vertical-Axis Wind Turbines (VAWTs) are known as the most suitable wind turbine for small-scale electrical generation. There are many types of VAWTs and each of it has different performances and efficiency. In this work, three types of VAWT systems (Savo-B2, Savo-B4 and Giro-B3) were designed, constructed and tested to investigate the amount of electrical power that could be generated under several constant wind speeds. The blade rotors were designed and built using 2 mm thickness of aluminum plate. The tip speed ratios, power coefficients, blade rotations for each blade rotor and the simplicity of the proposed designs were studied via an experimental setup. The experimental work demonstrates that Savo-B2 provides the highest power coefficient which is up to 0.32. Meanwhile, Giro-B3 offers the fastest rotational blade speed, up to 20.53 rad/s, among the three designs.
Behavior of Biodegradable Oil under Impulse Voltages
Authors: Katim Nurul Izzatul Akma , Ishak Mohd Taufiq , Ishak A.M. , Kadir M.Z.A.A.
Published: August 2015

The properties of Palm Oil (PO) and Coconut Oil (CO) offer the potential for transformers with non-toxicity, high fire and flash points and better environmental compatibility while compared with those filled with Mineral Oil (MO). This potential has led to intensive studies of electrical performance of biodegradable oil especially in evaluating the electrical performance under lightning impulse voltage in recent years. This paper presents the investigation on the impulse breakdown voltage of PO and CO in such a uniform field. The PO used in this study is Refined, Bleached and Deodorized Palm Oil (RBDPO) Olein type. Two testing methods, rising-voltage and up-and-down are considered for both oils with different gap distances (2.0 mm and 3.8 mm). Testing methods including rising-voltage method and up-and-down method have no notable influence on the breakdown voltages of RBDPOs and CO compared to MO.
Classification of Circuit Breaker Condition Based on Trip Coil Signature Analysis
Authors: Ahmad Harriezan , Poh Abdul Halim , Tiong Sieh Kiong
Published: August 2015

The idea of using circuit breaker profile as a part of initial assessment on switchgear is introduced as early as in 1996. Subsequently, there is a requirement to establish a systematical and analytical approach in managing and interpreting profile data. This paper aims to elaborate implementing Expert Rule Analysis (ERA) as part of a method in assessing performance of circuit breaker profile.
Analysis of Leakage Current on 11kV Zinc Oxide Surge Arrester Using Finite Element Method
Authors: Abdul Latiff Nurul Ain , Illias Hazlee Azil , Abu Bakar Ab Halim
Published: August 2015

Leakage current is known to be directly related to the degree of degradation of arrester. Leakage current is commonly flow across arrester under non-conducting condition. In this work, a two-dimensional (2D) axial-symmetrical 11kV surge arrester model was developed and used to simulate the leakage current under normal condition. The influence of insulator shed widths, housing materials and sizes of ZnO in an 11kV ZnO surge arrester design on its leakage current was studied using finite element method (FEM) software, which is COMSOL Multiphysics. The simulation results show that leakage current is mostly affected by the sizes of the ZnO and material of the housing. From this work, an understanding on the leakage current behaviors in a ZnO surge arrester can be enhanced. This study may also help in improving the design of surge arresters in reducing leakage current.
Classification of Power Quality Disturbance Based on Continuous S-Transform-Windowing Technique (CST-WT) and ANOVA as a Feature Selection
Authors: Daud Kamarulazhar , Abidin Ahmad Farid , Nagindar Singh Harapajan Singh , Mohd Hussain Mohd Najib
Published: August 2015

This paper was conducted in order to identify and classify the different types of Power Quality Disturbances (PQD) based on a new approach the Analysis Of Variance (ANOVA). ANOVA is used as feature selection for the PQD parameters. The datum of PQD from the PSCAD/EMTDC® simulation and Power Quality Monitoring has been validated before feature extraction analysis can be commenced. The obtained datum is then analyzed by using Windowing Technique (WT) based on Continuous S-Transform (CST) to extract the features and its characteristics. Moreover, the study focuses an important issue concerning the identification of PQD selection, detection and classification. The feature and characteristics of three types of signal such as sag, swell, and transient signal are obtained. The outcome of the analysis shows that a new approach framework ANOVA-Based Before and After Neural Network (NN) classification has a slightly increases to 15-25% in term of classification of PQD.
Maximum Loadability Identification Using Self-Tuning Algorithm Considering Voltage Limit
Authors: Che Mat Haris Harizan , Musirin Ismail , Mohd Kamal Mohamad Fadhil
Published: August 2015

Due to the complexity of power system nowadays, voltage limit has become a concerned issue. This phenomenon attracted numerous studies in finding the ultimate solution. This paper presents the development of self-tuning technique for identifying maximum loadability for selected buses in a power system network. The algorithm is able to perform fast process in consideration of the voltage limit between 0.9 p.u. to 1.05 p.u. as the acceptable voltage limit in power system community. The proposed concept is conducted for single and multi-load increment; executed on IEEE 14-Bus RTS and IEEE 26-Bus RTS. The proposed technique is feasible for larger transmission system implementation, which in turn avoid computation burden to power system operators.
Modified Novel Line Stability Factor Index with Reactive Power Tracing for Identification of Vulnerable Buses in Power System
Authors: Verayiah Renuga , Mohamed Azah , Shareef Hussein , Zainal Abidin Izham H.J.
Published: August 2015

Many power tracing techniques have been developed but are limited to the application of transmission service pricing in a deregulated environment. To expand the knowledge of power tracing theory and its application, this paper adopts the power tracing theory into voltage stability improvement. This paper proposes a modified novel line stability factor index with load tracing capability known as LQP_LT for the purpose of finding the appropriate locations in a power system network for any preventive and corrective actions. Unlike the commonly applied real power tracing, this method presents the reactive power tracing utilizing the proportional sharing method (PSM) with all the line reactive losses being taken into consideration in the network study with the system size remain the same. IEEE 5 bus system is used to demonstrate the LQP_LT concept and all the results obtained are compared with modified Fast Voltage Stability Index with load tracing ability (FVSI_LT). The results obtained found to be efficient in determining the reactive power contributed by a certain load bus in a transmission line which ultimately responsible to cause a stressed line and overall voltage instability in a system.
Injection Impact of Photovoltaic Distributed Generations (PVDG) on Power Distribution System Stability
Authors: Suyono Hadi , Zainuddin Muammar
Published: August 2015

Utilization of photovoltaic power plants on distribution system has been widely used in many countries. Commonly, the photovoltaic system has been injected to the distribution system and called as photovoltaic distributed generations (PVDG) through medium or low voltage levels. The injection of the PVDG on the distribution system has been claimed to improve the voltage profile and reduce power losses. However, the good performance of the distribution system in term of the steady-state point of view, cannot directly guarantee to give a good response during the system disturbed. Therefore, to show the impact of the PVDG injection on power system stability is concerned in this paper. The size of the power injection and location of the injection site that have been determined by using the optimization technique, are then analyzed based on three scenarios, each of which represents the PVDG injection of 2x0.5MW, 4x0.5MW, and 6x0.5MW respectively at different bus locations. The voltage-, frequency-, and rotor angle-stabilities are analyzed to show the dynamic impact of the PVDG during three-phase fault condition. The analysis results indicate that the second scenario gives the best response in term of the rotor angle-, frequency-, and voltage-responses during dynamic conditions which supplies active power around 28.78% of the total load. The PVDG injection power in the first scenario (14.39% of total load) and also in the third scenario (43.18% of total load) would result in rotor angle and frequency responses with more oscillations being compared to the second scenario. However, the system dynamic responses for all scenarios show damped oscillations to reach the steady-state conditions.
Optimization of Automatic Transformer Tap Changer Using Cascaded-Evolutionary Programming Technique
Authors: Mohamad Zahir Mohamad Ariff Nur Hakim , binti Abd Manap Nur Ain , Che Mat Haris Harizan , Musirin Ismail , Mohd Kamal Mohamad Fadhil
Published: August 2015

In power system, load variation can cause instability condition. Transformer Tap Changer (TTC) adjustment can be used to alleviate this condition. This paper proposes an algorithm to optimize the adjustment of TTC termed as Cascaded-Evolutionary Programming (EP). This is to allow fine-tuning process on the results if the optimized results are beyond the acceptable range. The Tests were conducted on IEEE 14-Bus Reliable Test System (RTS) to determine minimum Voltage Profile (VP),Vmin at selected load bus, using ordinary Load Flow thus maintaining the voltage at 0.9 p.u. to 1.5 p.u. The result demonstrates the pre-optimization and post-optimization of the minimum VP, Vmin in the system and proves that the proposed algorithm technique identifies the optimum value of TTC whilst reducing computational time.
Severe Total Loading Condition Attributed by a Significant Impact of Dynamic Power System Cascading Collapse
Authors: Salim Nur Ashida , Othman Muhammad Murtadha , Musirin Ismail , Serwan Mohd Salleh , Busan Stendley
Published: August 2015

Cascading outage is a sequence of multiple dependent component outages that gradually happened in a power system. One of the main reasons is due to the hidden failure in a protection system that may cause to a power system instability leading to a system cascading collapse. This paper presents a computationally realistic technique used to determine the estimated average probability of a dynamic system cascading collapse in conjunction with the effect of hidden failure on a protection system. This includes a realistic calculation of the probability of hidden failure as it will provide significant impact on the results of the estimated average probability of dynamic system cascading collapse. The estimated average probability of a system cascading collapse is then used to identify the severity of total loading condition leading to a higher risk of a dynamic system cascading collapse. This information is essential for the reason that it will assist the power system utility to determine the highest point of increased system loading condition before the occurrence of critical power system cascading collapse.
Fault Distance Calculation in Radial Distribution System Using Second Order Polynomial Analysis of Voltage Sag Profile
Authors: Gururajapathy S.S. , Mokhlis Hazlie , Illias Hazlee Azil , Awalin Lilik Jamilatul
Published: August 2015

This paper proposes a nonlinear analysis of voltage sag magnitude and angle for fault distance calculation in distribution system. The method first identifies the fault section. Then, a rank approach is followed to identify and prioritize the faulty section. Later, the fault distance is calculated by creating a second order polynomial passing through the fault node. The testing is carried out in an actual distribution system of an electrical utility in Malaysia with 37 nodes. The test results show that the proposed fault distance gives very small percentage error.
Competitive Bidding Exercise for the First Track Gas-Fired Power Plant in Prai Malaysia; Revenue Assessment for a New Plant
Authors: Abdul Aziz M.A. , Dahlan Nofri Yenita , Shokri S.M.
Published: August 2015

Competitive bidding exercise for a new power generation has been introduced in 2011 to bring Malaysia Electricity Supply Industry (MESI) into competitive electricity market. The competitive bidding process is an auction based mechanism organized by Energy Commission (EC) Malaysia. EC has successfully completed two auctions; 1) international competitive bidding exercise (Track 1) for a new capacity in Prai Penang, Malaysia and 2) restricted tender (Track 2) for the renewal of operating licenses of the first generation Independent Power Producer (IPP) and Tenaga Nasional Berhad (TNB) power plants. The Track 1 has won by Tenaga Nasional Berhad (TNB) for a 1,071 MW CCGT power plant, at a levelised tariff of 34.7 sen/kWh. On the other hand Track 2 has been awarded to Genting Sanyen Power and Segari Energy Ventures for another 10 years extension and TNB Pasir Gudang for another 5 years extension. This paper discusses the competitive bidding exercise implemented in Malaysia for new power plants. It also evaluates the revenues of TNB from the Track 1 bidding exercise. Sensitivity analysis is performed to study the impact of uncertainty in the fuel price, capacity rate financial and fixed and variable operating rate on the revenue of the plant. Result shows that the changes in the fuel price are the largest source of uncertainty for business investment in power plant and biggest variable in determining levelised.
Solving Fuzzy Combined Economic Load–Emission Dispatch by Using Differential Evolution Immunized Ant Colony Optimization Technique
Authors: Rahmat Nur Azzammudin , Musirin Ismail , Abidin Ahmad Farid
Published: August 2015

The fluctuating load demand with respect to time requires thorough analysis by the energy providers. Nowadays, the utilities need to include emission control during energy dispatch planning. The practically accurate economic dispatch solution is achieved by considering it as a dynamic or time-varying problem. Therefore, this research proposes Fuzzy Combined Economic Load-Emission Dispatch (Fz-CELED) to solve dynamic economic dispatch problem. Fuzzy Logic is used to predict the future load demand and fuel pricing. Moreover, this paper proposed the Differential Evolution Immunized Ant Colony Optimization (DEIANT) technique to optimize Fz-CELED problem. The research was conducted on IEEE 57-Bus Systems. Comparative studies are also conducted among DEIANT, ACO and EP to assess their performance.
Ranking Index in the Pareto Optimal Front Based Evolutionary Programming Technique for Best Selection of Several Optimal Multi-Objective Capacity Benefit Margins
Authors: Othman Muhammad Murtadha , Abd Rahman Nurulazmi , Musirin Ismail
Published: August 2015

The amount of power transfer between areas is purporting as imperative information required by the utility so that this will assist them towards an effective operation of electricity market performed in a deregulated power system. CBM is defined as the amount of the transfer capability reserved by the load-serving entities which will be used during the case of generation deficiency. This paper presents a new approach used to perform simultaneous determination of capacity benefit margin (CBM) for all areas by using the evolutionary programming (EP) technique. Ranking index in the Pareto optimal front cluster of total loss-of-load expectation (LOLE) and total LOLE difference will be used for selecting several best solutions of multi-objective CBMs. Eventually, performance of the proposed method is investigated thoroughly via a test system of modified IEEE-RTS79. Utilization of the proposed technique is superior in terms of offering flexibility to the utility in selecting several best solutions of multi-objective CBMs.
Optimum Generation Mix Possibilities for Malaysia Power Sector in 2030
Authors: Mohd Shokri Siti Mariam , Dahlan Nofri Yenita , Ahmad Norlee Husnafeza
Published: August 2015

This paper presents findings from optimization of a long-term generation mix for Malaysia electricity power supply using Dynamic Programming (DP) technique. The optimization is modelled to minimize the total costs as the objective function subjects to demand and policy constraints. . Several technologies have been used for generation candidates such as coal, gas and nuclear. The model has been tested on a generation portfolio based on Malaysia power system. Result shows that a balance generation mix for Malaysia in 2030 will be 30% is from coal, 31.6% from gas, 17.5% from nuclear, 6.8% from hydro and 14% from RE.