2016 Cilt 21 Sayı 1

Permanent URI for this collectionhttps://hdl.handle.net/11452/11719

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Now showing 1 - 7 of 7

Analysis of material position and size in a waveguide fed resonator
(Uludağ Üniversitesi, 2016-02-09) Kent, Sedef; Süle, Okan; Uludağ Üniversitesi/Mühendislik Fakültesi/Elektrik-Elektronik Mühendisliği Bölümü.
The main factors that affect electric field distribution, and therefore heat distribution, are the dimensions of the resonator, heating frequency, shape and dielectric properties of the material to be heated, position of the material to be heated within the resonator and the position of the feed guide on the resonator. From among these factors that directly affect heating, this work examined the material thickness. The purpose of this study was to determine the material thickness that will minimise the reflection coefficient. The accuracy of the results obtained by means of the mode matching method was demonstrated by comparing those results with the results obtained through Ansoft’s High Frequency Structure Simulator.
Determination of optimum thermal insulation thicknesses for external walls considering the heating, cooling and annual energy requirements
(Uludağ Üniversitesi, 2016-06-14) Kaynaklı, Ömer; Kaynaklı, Faruk; Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.; Uludağ Üniversitesi/ Gemlik Asım Kocabıyık Meslek Yüksek Okulu.
In this study, optimization of thermal insulation thickness applied to the external walls of buildings has been carried out comparatively based on the seasonal (space-heating and cooling) and the annual energy requirements considering solar radiation effect. This study has been performed for four degree-day regions of Turkey, namely, Iskenderun (in the first region), Istanbul (in the second region), Ankara (in the third region) and Ardahan (in the fourth region). By determining the sol-air temperatures for each region and maximizing the present worth value of seasonal and annual energy savings, the optimum thermal insulation thicknesses have been calculated. The effects of solar radiation on heatingcooling energy requirements, the variation of optimum insulation thicknesses and payback periods with respect to degree-day regions, the differences between the analyses based on seasonal and annual have been presented in tabular and graphical form.
Differential equation solver simulator for runge-kutta methods
(Uludağ Üniversitesi, 2016-01-19) Hatun, Metin; Vatansever, Fahri; Uludağ Üniversitesi/Mühendislik Fakültesi/Elektrik-Elektronik Mühendisliği Bölümü.
Many of problems in engineering and science is modeled by differential equations mathematically, therefore their solutions have an important role. Various methods have been developed for analytical or numerical solutions of differential equations. In proportion to the development of technology, the numerical solution methods are utilized widely. In particular, the main objectives in real time applications are to reach the correct solution as soon as possible with minimal processing and maximum precision. In the performed study, a simulator that contains Runge-Kutta based forty-eight methods was developed for numerical solution of differential equations. In the user friendly simulator which can be used also for educational purposes, the solution of defined differential equation under the specified initial condition with given step size or according to the number of points requested within the specified range can be obtained by the selected method. Solutions can be presented to the user both numerical (step values, computation time) and graphically; also the subject explanations about the methods/solutions can be given. Furthermore, the comparative solutions (performance analysis) can be implemented by the simulator. So, the users can realize the numerical solutions of differential equations with different methods by the simulator; the students learn the methods in this field visually with the aid of subject explanation and can implement step by step; the designers can choose the most appropriate method easily, effectively and accurately for their systems by the comparative analysis.
Experimental and numerical investigaton of strawberry drying
(Uludağ Üniversitesi, 2016-05-30) Tan, Fuat; Canbolat, Ahmet Serhan; Yüce, Bahadır Erman; Türkan, Burak; Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.
Strawberry drying was investigated experimentally and numerically in this study. In the experiments, samples of strawberry slices with 1 cm thicknesses were used to investigate the effect of the drying air velocity. 5-hour experiments were conducted for three different velocities (0.5, 1 and 2m/s) at 70°C air temperature. It was observed that increasing the drying air velocity from 0.5 up to 2 m/s decreased the drying duration by 17% on average. Moreover, the data obtained from the experimental study were compared to the numerical results. The results were found compatible with each other. Finally, the effect of air temperature and product thickness on drying was examined numerically.
Experimental and theoretical analysis of headlight surface temperature in an infrared heated stress relieving oven
(Uludağ Üniversitesi, 2015-03-11) Mutlu, Mustafa; Kılıç, Muhsin; Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.
In this study, the IR heated stress relieve oven, was experimentally and theoretically examined. In experimental measurements, temperature was measured on headlight surface, placed in IR oven, at various conveyor speeds and various distances between IR lamps and headlight surface. In theoretical study, a mathematical model was developed for the headlights surface temperature by using heat transfer theory. The results obtained by the mathematical model and the measurement showed very good agreement with 6.5% average error. It is shown that mathematical model can be used to estimate the surface temperatures in case of different conditions were run in oven.
New designs in circulation areas and museums the case of the quai branly museum
(Uludağ Üniversitesi, 2016-01-01) Ataoğlu, Nihan Canbakal
During the Pre-Modern Era of 1970s; new buildings questioning general typologies and offering advances in terms of design and function are started to be built. Architects not only looked for unattempted block structures but also their quest for unattempted block structures were continued for internal places, too and internal implicit setups were designed using ortographic tools like plans and sections. In today’s museums; new and multiple circulation routes are designed; in which visitors do not read books from beginning to end but choose their own paths and walk through the exhibition as if in a labyrinth on their own. These radical perceptional, spatial changes and spatial scenarios are particularly emphasized in museum buildings. These new spatial arrangements in circulation areas are offering new spatial experiences with irregular gaps in sections, regular but non-geometric floor plans, vagueness of the borders, striking colors, patterns and materials, differentiated circulation parts (stairs, moving stairways, elevators, platforms, bridges). In the study; Jean Nouvel’s Quai Branly Museum (2006) which is a recent example of this striking change will be analyzed thorough spatial experiences, observations, geometrical analysis technique and spatial examinations.
Wire electrical discharge machining of a hybrid composite: Evaluation of kerf width and surface roughness
(Uludağ Üniversitesi, 2016-06-17) Motorcu, Ali Rıza; Ekici, Ergün; Kuş, Abdil; Uludağ Üniversitesi/Teknik Bilimler Meslek Yüksek Okulu/Makina Programı.
In this study, the machinability characteristics of Al/B4C-Gr hybrid composite were investigated using wire electrical discharge machining (WEDM). In the experiments, the machining parameters of wire speed, pulse-on time and pulse-off time were varied in order to explaiın their effects on machining performance, including the width of slit (kerf) and surface roughness values (Rz and Rt). According to the Taguchi quality design concept, a L18 (21×32) orthogonal array was used to determine the S/N ratio, and analysis of variance (ANOVA) and the F-test were used to indicate the significant machining parameters affecting the machining performance. From the ANOVA and F-test results, the significant factors were determined for each of the machining performance criteria of kerf, Rz and Rt. The variations of kerf, Rz and Rt with the machining parameters were statistically modeled via the regression analysis method. The optimum levels of the control factors for kerf, Rz and Rt were specified as A1B1C1, A1B1C2 and A1B1C2, respectively. The correlation coefficients of the predictive equations developed for kerf, Rz and Rt were calculated as 0.98, 0.828 and 0.855, respectively.

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