2017 Cilt 22 Sayı 1

Permanent URI for this collectionhttps://hdl.handle.net/11452/11961

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An analytical approach for material synthesis based on shielding effectiveness characteristics
(Uludağ Üniversitesi, 2017-02-27) Erbaş, Cihan Döğüşgen; Kent, Sedef
We describe an analytical method to synthesize a Debye-like equivalent homogeneous material by computing the associated parameters such as static relative permittivity, relative high-frequency limit permittivity, relaxation time, and the width of the material for a given shielding effectiveness specification and a given range of frequency as well as material width. We illustrate the parameter extraction procedure with a numerical example, in which we validate that the applied method is able to produce the desired SE profile within the specified frequency range.
Assessment of water and wastewater potential of Bursa city
(Uludağ Üniversitesi, 2017-03-02) Teksoy, Arzu; Nalbur, Berrak Erol; Solmaz, Seval Kutlu Akal; Mühendislik Fakültesi; Çevre Mühendisliği Bölümü
Urban growth is increasing the demand for freshwater resources and water is of significant importance for cities. Many fast growing megacities are facing serious water-related problems including pollution, eutrophication, missing wastewater treatment and perhaps most importantly, a severe scarcity of clean water. In the entire urban world, water resources are used in an inefficient way. Bursa is one of the wealthiest cities in terms of its supply of drinking and general purpose water in Turkey. Apart from rich freshwater resources Bursa has also thermal water springs. Bursa can be a sample city with its environmentally respectful water management system and foresighting in terms of water resources and wastewater treatment facilities.In this paper, Bursa a metropolitan city located in South Marmara Region of Turkey and which has come into prominence with wealthy water resources was evaluated in terms of water consumption and water resources. Several recommendations were scrutinised in order to protect current water capacity and proper usage of water for a planned and well-designed water management of the city. Wastewater treatment facilities were also stated within the frame of the paper. This paper concludes by suggesting ways of enhancing the resources of water and wastewater services in Bursa.
Behaviour of free and fixed-head offshore piles under cyclic lateral loads
(Uludağ Üniversitesi, 2017-04-28) Taşan, H. Ercan
Offshore piles are subjected to cyclic lateral loads due to environmental loads, such as wind and waves. These loads can lead to an accumulation of permanent soil deformations and excess pore water pressures in saturated soils. Finite element analyses are performed to investigate the behaviour of cyclic laterally loaded free-head and fixed piles embedded in sandy saturated soil while considering such accumulation effects. A three-dimensional fully coupled two-phase finite element is developed and implemented on the basis of a two-phase model to consider the pore water pressure development in saturated soil. In addition, a hypoplastic constitutive model is used to describe the material behaviour of sandy soil under cyclic loading. In the numerical analyses, special attention is dedicated to interactions between the pile, the saturated soil and the pore water. The results have shown that the pile displacements caused by cyclic lateral loads are significantly underestimated for both pile head conditions by approaches which do not take into account the impact of the pore water pressure development in saturated sandy soil of the pile response.
A comparison of atmospheric correction methods on hyperion imagery in forest areas
(Uludağ Üniversitesi, 2017-02-28) Cetin, Mufit; Musaoglu, Nebiye; Kocal, Osman Hilmi
The reflectance values recorded by Earth observing satellite sensors can be different from the surface reflectance values measured on the ground due to interference of gases and water vapor in the atmosphere. Therefore, atmospheric correction is a significant procedure to derive the true surface reflectance value during the processing of remotely sensed imagery especially with hyperspectral data. In this context, this study attempts to analyze the quality of the surface reflectance derived from EO-1 Hyperion hyperspectral imagery using the atmospheric radiative transfer (RT) models (FLAASH and ATCOR) and empirical line (EL) method. In the study, ground-based reflectance measurements derived from ASD FieldSpec spectroradiometer are used as reference to evaluate the quality of the retrieved surface reflectance. The results showed that EL and ATCOR methods achieved the best results for reducing some of the atmospheric effects, but FLAASH method resulted in strong anomalies in the corrected reflectance.
Effect of language mismatch on turkish speaker verification
(Uludağ Üniversitesi, 2017-04-21) Hanilçi, Cemal
In this paper, effect of language mismatch between background data and evaluation data is analyzed for text-independent speaker recognition in particular for Turkish spoken language. Gaussian mixture model with universal background model (GMM-UBM) classifier is utilized using Mel-frequency cepstral coefficients (MFCCs) as speaker-specific features. Experiments conducted on a Turkish speech database consisting of 47 male and 26 female speakers reveals that Turkish speaker recognition performance dramatically degrades in case of language mismatch between UBM and the evaluation data. For example 1.73% and 12.34% equal error rates (EERs) are obtained for male speakers when UBM is trained using Turkish and English data, respectively.
Influence of women’s dress woven fabric structure on bending and drapability properties
(Uludağ Üniversitesi, 2017-04-11) Gürarda, Ayça; Çeven, Erhan Kenan; Mühendislik Fakültesi; Tekstil Mühendisliği Bölümü
Good tailorability is a required property for clothing manufacturers. Fabrics will be able to pass through the garment manufacturing process easily without any problems for good apperance and wear performance. Functionality of a garment can be improved by the combination of fibre, yarn, fabric or garment stages. In recent years, women’s dress fabrics have an important place in the fabric industry. Most women’s dresses are complex products, resulting from fibre, yarn, fabric and garment structure combined with mechanical and chemical finishing procedures to provide a garment that meets of all the requirements of users like aesthetic, design, fit or performance. First of all, softness, drapability and comfort are required for women’s dresses. In this study, we investigated the influence of women’s dress viscose woven fabric structure on bending and drapability properties.
Numerical simulation of 4-digit inclined NACA 00xx airfoils to find optimum angle of attack for airplane wing
(Uludağ Üniversitesi, 2017-02-28) Sogukpinar, Haci
In this paper, numerical analysis was conducted by using the SST turbulence model for inclined NACA 0008, 0009, 0010, 0012, 0015, 0018, 0021, 0024 airfoils. Aerodynamic numerical analysis of NACA 0012 airfoil was compared with the previously made experimental results in terms of pressure and lift coefficient. The theoretical data were found to be fully compatible with experimental results. Then, by simulating other airfoils using the same methods lift, drag, lift to drag ratio and the pressure coefficient were calculated and compared with the angle of attack 0-14 degrees. According to the calculations, lift coefficient of NACA 0008-0012 airfoil shows similar behaviors. With the increasing of the airfoil thickness increment in the lift coefficient decreases for NACA 0015-0024 airfoils. Pressure coefficients were also calculated for NACA profiles with angle of attack 10°. Pressure coefficients over the airfoil decrease from leading edge toward the trailing edge but in the lower part it increases. With the increasing of the airfoil thickness pressure coefficient decreases more slowly at the upper part but increases more rapidly at the lower.

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