Mechanical Engineering / Makina Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4129
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Article Citation - Scopus: 1Sizing of Autonomous Wind/Solar Hybrid Energy Conversion Systems for Urla, Turkey(ACTA Press, 2009) Özerdem, Barış; Ekren, OrhanIn this paper, an optimum sizing procedure of autonomous hybrid (wind + solar) energy system is presented which can be used to satisfy the requirements of given load distribution. The main purpose of this study is to find out an appropriate wind-photovoltaic hybrid energy system to satisfy electricity consumption of GSM (Global System for Mobile communication) base station at Izmir Institute of Technology Campus Area, Urla, Izmir, Turkey. To do this, monthly average daily solar radiation and wind speed data are collected. The monthly average wind speeds are measured at 10 m height during 3 years period on Izmir Institute of Technology Campus Area. The monthly average wind speed values are obtained between 5.7 and 7.7 m/s, on the other hand, the monthly average daily value of solar radiations on horizontal surfaces are ranged from 1.4 to 6.9kWh/m2 at Izmir Institute of Technology Campus Area. The hybrid system considered in the present analysis consists of one 5kW nominal power wind energy conversion systems (WECS), 21.82 m2 of photovoltaic (PV) panels (18 mono crystal PV panels each having 75 W power output) together with a battery storage system.Article Fireproofing the Firefighting Robot(Laurin Publishing Co. Inc., 2009) Keçeci, Emin FarukResearchers at the Institute of Technology in Izmir, Turkey, have successfully developed a mechanical firefighter robot that will work inside the flames. The robot uses both passive and active cooling systems that, for a limited time, keep the inner temperature at a safe level for the electronic components inside the device, to survive the flame. The body of the robot is made of aluminum and comprises two shells attached to each other with rods. The robot is controlled with a remote unit by an operator, who can observe the fire via a CCD camera. Control and cooling subsystems will allow the robot to work in these rough conditions. The control system allows the robot to use the navigation system as well as the sensory and cooling systems. The robot will be controlled with radiofrequency communications and is able to break doors and climb stairs to work in upper-level fires.Conference Object Citation - WoS: 9Citation - Scopus: 13Design of a Haptic Device for Teleoperation and Virtual Reality Systems(Institute of Electrical and Electronics Engineers Inc., 2009) Dede, Mehmet İsmet Can; Selvi, Özgün; Bilgincan, Tunç; Kant, YalkınHaptics technology has increased the precision and telepresence of the teleoperation and precision of the in-house robotic applications by force and surface information feedback. Force feedback is achieved through sending back the pressure and force information via a haptic device as the information is created or measured at the point of interest. In order to configure such a system, design, analysis and production processes of a haptic device, which is suitable for that specific application, becomes important. Today, haptic devices find use in assistive surgical robotics and most of the teleoperation systems. These devices are also extensively utilized in simulators to train medical and military personnel. The objective of this work is to design a haptic device with a new structure that has the potential to increase the precision of the robotic operation. Thus, literature is reviewed and possible robot manipulator designs are investigated to increase the precision in haptics applications. As a result of the investigations, conceptual designs are developed. Ultimately, final design is selected and produced after it is investigated in computer-aided- design (CAD) environment and its kinematic and structural analyses are carried out.Book Part Citation - Scopus: 6Swarm and Entropic Modeling for Landmine Detection Robots(Springer Verlag, 2008) Bayram, Çağdaş; Sevil, Hakkı Erhan; Özdemir, SerhanEven at the dawn of the 21st century, landmines still pose a global threat. Buried just inches below the surface, combatants and noncombatants alike are all at risk of stepping on a mine. Their very nature is such that these furtive weapons do not discriminate, making it an urgent task to tackle the problem. According to the U.S.State Department [1], based on an estimate reported just a few years ago, there are well over 100 million anti-personnel mines around the world. The existence of these passive weapons causes a disruption in the development of already impoverished regions, as well as maiming or killing countless innocent passers-by. Since the ratification of the anti-personnel mine total ban treaty in 1997, their detection, removal, and elimination have become a top priority. Nevertheless, at the current rate, given the manpower and the man-hours that could be dedicated to the removal of these sleeping arms, it would take centuries. The concerns regarding the speed of removal and safety of the disposers eventually bring us to the discussion of the proposed method. Nature already provided good solutions to manage groups of less able beings: fish schools, ant swarms, animal packs, bird flocks, and so on.With the growing desire of humans to create intelligent systems, these biosystems are being thoroughly inspected [3-10] and implemented [11-14] in various studies. In this study a robotic agent is referred to as a drone, the group of robotic agents is referred to as a swarm, and the agent with mapping abilities is referred to as the alpha drone.Article Doe and Ann Models for Powder Mixture Packing(American Ceramic Society, 2007) Akkurt, Sedat; Romagnoli, Marcello; Sütçü, MücahitDesign of experiments (DOE) and artificial neural network (ANN) techniques were used to study packing of fused alumina powders composed of three different sizes of particles. The first is the mixture design technique that produces a polynomial model of the powder-packing system. While, the ANN technique is extensively used to model complex systems in many fields. The methodological approach used is mixture design, which can be used to study the influences of two or more additives. It is a structured and organized method for determining the relationship between the components and the output of that process. The mixture design approach permits optimization of size distribution to obtain a target value of porosity. Sensitivity analysis involves the use of the developed ANN model to predict outputs (porosity) at varying levels of the input factor effects.Article Citation - WoS: 3Citation - Scopus: 5Electrical and Thermal Properties of the Gasb-Fega1.3 Eutectic(MAIK “Nauka/Interperiodica”, 2004) Aliev, M. I.; Khalilova, A. A.; Arsaly, D. G.; Ragimov, R. N.; Tanoğlu, MetinThe electrical conductivity, thermoelectric power, Hall coefficient, and thermal conductivity of the GaSb-FeGa1.3 eutectic were measured in a wide temperature range at different relationships between the directions of the electric current, heat flux, magnetic field, and needlelike metallic inclusions. The results are interpreted in terms of electronic and phonon processes. The metallic inclusions are shown to have a significant effect on the transport properties of the eutectic.Conference Object Microstructure-Performance Relation in Pmma-Based Open-Cell Porous Materials for High Pressure Ceramic Sanitaryware Casting(Trans Tech Publications, 2004) Ergün, Yelda; Dirier, C.; Yılmaz, M.; Tokman, C.; Tanoğlu, MetinThe ceramic whiteware/sanitaryware industry is rapidly undergoing to implement high-pressure casting techniques for ceramic article production. In these techniques, materials with open pore microstructure that allows drainage of water under applied pressure are needed. The polymethyl methacrylate (PMMA) based polymeric porous materials have become the most suitable type of materials for this purpose because of their short casting periods and high service lives. However, the superior service life and performance of these materials are closely related to the microstructure. In the present study, the porous materials with various compositions of the constituents in the emulsion were produced to effect the microstructure of PMMA-based materials. The variations on the pore microstructure were interrelated to the performance of the material for high-pressure sanitaryware casting. The pore morphology and water permeability of the samples was measured using optical and SEM microscopy and permeability measurement techniques, respectively. The compressive collapse stress and modulus values were determined by performing compression testing. The results showed a significant interrelation between microstructure and the performance of the PMMA-based ceramic mould materials.Conference Object Citation - WoS: 7Citation - Scopus: 7Investigation of the Pozzolanic Properties of Bricks Used in Horasan Mortars and Plasters in Historic Buildings(Trans Tech Publications, 2004) Böke, Hasan; Akkurt, Sedat; İpekoğlu, BaşakCrushed brick used in historic brick-lime mortars and plasters (Horasan) were characterized for understanding their properties to develop intervention mortars for conservation. Brick powders were separated from original mortars and plasters, and analyzed by XRD, SEM-EDS, TGA and pozzolanic activity (PA) measurements. The results showed that the microstructures of brick powders were not completely vitrified, and their XRD analysis failed to show the peaks for high temperature (T>900°C) phases. PA measurements of all brick powders showed an ample amount of artificial pozzolan property. Consequently, brick powders aimed for conservation of historic mortars must have high clay contents in addition to being low-fired (T<900°C) in order to produce maximum conversion into amorphous phase for ideal PA values.Conference Object Citation - Scopus: 1Microstructural Characterization of Industrial Chromite and Spinel Cement Kiln Refractories With Emphasis on the Iron-Rich Rims(Trans Tech Publications, 2004) Mercanköşk, Y.; Akkurt, Sedat; Çiftçioğlu, MuhsinMagnesia-chromite (MgO + MgO·Cr2O3) and magnesia-spinel (MgO + MgO·Al2O3) refractory bricks that are used in the high temperature zones of rotary cement kilns are investigated for their microstructural characteristics. Their microstructures are important because the size, shape and distribution of periclase grains, chromites and the quality of their bonding phases significantly affect their service performances. The purpose of this study was to characterize the microstructures of industrial brick samples to develop a protocol to compare different products e.g. for evaluation as replacement bricks. In some of the chromite containing bricks iron-rich rims were observed, while a domestic brick with similar chemistry had no such feature. These iron-rich rims were examined using SEM-EDS. It was found that the counter-diffusion of Fe+3 and Cr+3 were responsible for their formation. Exsolved chrome-spinel was widely observed in the microstructures of chromite bricks. Magnesia-spinel bricks were found to contain low melting calcium aluminates as bond phases in the microstructure, posing a threat to service performance. Portmortem microanalysis of industrially used bricks revealed alkali attack in addition to creep as main destruction mechanisms for brick. Traces of elements like Mo, S and alkalies were observed and thought to originate from the use of waste derived fuels.Conference Object Citation - WoS: 8Citation - Scopus: 12Mechanical Properties of Hydroxyapatite Composites Reinforced With Hydroxyapatite Whiskers(Trans Tech Publications, 2004) Şimşek, Deniz; Çiftçioğlu, Rukiye; Güden, Mustafa; Çiftçioğlu, Muhsin; Harsa, Hayriye ŞebnemSintering and mechanical behavior of pure and hydroxyapatite (HA) whisker reinforced HA composites were investigated in this work. Pure and composite samples were prepared by using a commercial powder and whiskers prepared by molten salt synthesis. The dry-pressed samples were sintered in the 800 and 1300°C range. The effect of whisker-addition on the mechanical properties of HA was investigated through compression and hardness testing. Compressive strength and fracture strain were observed to increase by the addition of whiskers.