IJET Vol. 2, Issue 3, September 2016
Bu koleksiyon için kalıcı URI
International Journal of Engineering Technologies (IJET) Dergisi / International Journal of Engineering Technologies (IJET)
Güncel Gönderiler
Öğe International Journal of Engineering Technologies (IJET) Vol. 2, Issue 3, September 2016(İstanbul Gelişim Üniversitesi Yayınları / Istanbul Gelisim University Press, 2016) Çolak, İlhamiDear Colleagues, On behalf of the editorial board of International Journal of Engineering Technologies (IJET), I would like to share our happiness to publish the seventh issue of IJET. My special thanks are for members of editorial board, editorial team, referees, authors and other technical staff. Please find the seventh issue of International Journal of Engineering Technologies at http://dergipark.ulakbim.gov.tr/ijet. We invite you to review the Table of Contents by visiting our web site and review articles and items of interest. IJET will continue to publish high level scientific research papers in the field of Engineering Technologies as an international peerreviewed scientific and academic journal of Istanbul Gelisim University. Thanks for your continuing interest in our work, Professor ILHAMI COLAK Istanbul Gelisim University icolak@gelisim.edu.tr http://dergipark.ulakbim.gov.tr/ijet Printed ISSN: 2149-0104 e-ISSN: 2149-5262Öğe Dynamic Spectrum Access: A New Paradigm of Converting Radio Spectrum Wastage to Wealth(İstanbul Gelişim Üniversitesi Yayınları / Istanbul Gelisim University Press, 2016-09-14) Popoola, Jide J.; Ogunlana, Oluwaseun A.; Ajie, Ferdinad O.; Olakunle, Olaleye; Akiogbe, Olufemi A.; Ani-Initi, Saint M.; Omotola, Sunday K.Abstract-The study presented in this paper reveals the limitations of the current fixed radio spectrum allocation policy as a major bottleneck for availability of radio spectrum for emerging wireless services, devices and applications as a result of its contributions to current radio spectrum artificial scarcity and underutilization problems. In investigating these problems scientifically, series of radio spectrum occupancy studies were carried out in developed nations of the world with little or none in most under-developed nation like Nigeria. In order to ascertain the usage profile of radio spectrum in under-developed nation like Nigeria, actual radio spectrum usage in three different locations in South-West Geo-political zone of Nigeria was carried out. The study was conducted using Aaronia AG HF-6065 V4 spectrum analyzer. The results obtained like other similar studies conducted in other parts of the world show that the usage of radio spectrum varies with time, space and frequency. The results also show that the actual radio spectrum usages in the three locations for the frequency range of 80-2200 MHz vary from 0.08% to 64.4%. In addition, the paper enumerates various ways of converting the current wasting spectrum holes to wealth as well as some economic advantages of dynamic spectrum access as a flexible radio access policy that can replace the current fixed radio spectrum allocation policy without compromising the performance of the existing radio being governed by the fixed spectrum allocation policy.Öğe Fluorescent Lamp Modelling and Electronic Ballast Design by the Support of Root Placement(İstanbul Gelişim Üniversitesi Yayınları / Istanbul Gelisim University Press, 2016-09-14) Alışkan, İbrahim; Keskin, RıdvanIt is presented that high frequency electronic ballast for fluorescent lamps is designed with root placement method using natural frequency and damping ratio. Also, a fluorescent lamp is designed as to have dynamic resistant. The method proposes simple mathematical calculations instead of complex mathematical calculations and the approaches based one of the component of resonant tank, which arbitrary chosen value. Also it is capable to provide accurate values, which can be employed in new types to ballasts. Natural frequency and damping ratio, which are parameters of the method, are chosen switching frequency, 0.707, respectively. Transfer function of electronic ballast circuit is calculated by means of proposed method. After that, components of the circuit are find out. 220 V(rms) voltage was achieved at ignition and obtained 30 W lamp power in state space operation. Electronic ballast design and a fluorescent lamp are made of using Matlab/Simulink interface and the results are presented.Öğe Analysis of Bending Deflections of Functionally Graded Beams by Using Different Beam Theories and Symmetric Smoothed Particle Hydrodynamics(İstanbul Gelişim Üniversitesi Yayınları / Istanbul Gelisim University Press, 2016-09-14) Karamanlı, ArmağanThe elastostatic deformations of functionally graded beams under various boundary conditions are investigated by using different beam theories and the Symmetric Smoothed Particle Hydrodynamics (SSPH) method. The numerical calculations are performed based on the Euler-Bernoulli, Timoshenko and Reddy-Bickford beam theories. The performance of the SSPH method is investigated for the comparison of the different beam theories where the beams are composed of two different materials for the first time. For the numerical results various numbers of nodes are used in the problem domain. Regarding to the computed results for Reddy-Bickford beam theory various numbers of terms in the Taylor Series Expansions (TSEs) are employed to improve the accuracy. To validate the performance of the SSPH method, comparison studies in terms of transverse deflections are carried out with the analytical solutions by using the global L2 error norm.Öğe Calculation and Optimizing of Brake Thermal Efficiency of Diesel Engines Based on Theoretical Diesel Cycle Parameters(İstanbul Gelişim Üniversitesi Yayınları / Istanbul Gelisim University Press, 2016-09-14) Karaman, Vedat; Yıldızhan, Şafak; Özcanlı, Mustafa; Serin, HasanIn this study, a theoretical study has been evaluated in order to calculate and optimize diesel engine brake thermal efficiency values. In the study three main parameters which are compression ratio, ratio of specific heat and cut-off ratio, based on ideal diesel cycle were evaluated. Compression ratio, ratio of specific heats and cut-off ratios were chosen between the interval of; 12:1-24:1, 1,2-1,4 and 1,5-3,0, respectively. Theoretical study showed that compression ratio significantly affects the engine characteristics that calculated in this study. Experiments revealed that the higher compression ratio results with higher brake thermal efficiency (BTHE) and thus lower specific fuel consumption (SFC). The calculation study showed that increasing cut-off ratio caused to decrease of brake thermal efficiency. Also, study revealed that increment of ratio of specific heats improved brake thermal efficiency.Öğe Development of a Lidar System Based on an Infrared RangeFinder Sensor and SlipRing Mechanism(İstanbul Gelişim Üniversitesi Yayınları / Istanbul Gelisim University Press, 2016-09-14) Bayar, Gökhan; Uludağ, AlparslanAbstract-Lidar systems are one of the most important sensor infrastructures in autonomous vehicles and mobile robots. They are used for achieving indoor and outdoor mapping purposes. In the scope of this study, a new perspective to develop a lidar system is proposed. The system developed is constructed based on a low-cost infrared rangefinder sensor, low-cost slipring mechanism designed and manufactured, dc motor and microprocessor. The rangefinder sensor is mounted to a head-structure actuated by a dc motor that continuously rotates with a desired rotational velocity. The data coming from the rangefinder sensor flows through the microprocessor via the slipring. The design concept of the slipring mechanism gives an advantage that the data of the infrared rangefinder sensor can be taken while the sensor continuously rotates. The required power for the sensor can also be supplied by the slipring during motion. The decoding process of the data coming from the rangefinder sensor and motor control task are accomplished using an ATmega based microprocessor. A user interface is also created to communicate with the system and evaluate the performance of the whole structure developed. After conducting many experiments, successful results are obtained. The design steps of the system proposed and the experimental results are presented in this paper.Öğe Elastostatic Deformation Analysis of Thick Isotropic Beams by Using Different Beam Theories and a Meshless Method(İstanbul Gelişim Üniversitesi Yayınları / Istanbul Gelisim University Press, 2016-09-14) Karamanlı, ArmağanThe elastostatic deformations of thick isotropic beams subjected to various sets of boundary conditions are presented by using different beam theories and the Symmetric Smoothed Particle Hydrodynamics (SSPH) method. The analysis is based on the Euler-Bernoulli, Timoshenko and Reddy-Bickford beam theories. The performance of the SSPH method is investigated for the comparison of the different beam theories for the first time. For the numerical results, various numbers of nodes are used in the problem domain. Regarding to the computed results for RBT, various number of terms in the Taylor Series Expansions (TSEs) is employed. To validate the performance of the SSPH method, comparison studies in terms of transverse deflections are carried out with the analytical solutions. It is found that the SSPH method has provided satisfactory convergence rate and smaller L2 error.
