Ozgener L.,Celal Bayar University
Renewable and Sustainable Energy Reviews | Year: 2010
The purpose of this survey is about to investigate wind energy potential of Celal Bayar University Muradiye Campus. The experimental system was commissioned in November 2006 and performance monitoring tests have been conducted since then. Author also undertake a case study to investigate how varying wind speeds considered affect the electricity production of the wind turbine system and to estimate a capacity factor which is defined as the ratio of the average power output to the rated output power of the generator. The collected data are quantified and illustrated in the tables, 07th of November 2006 till 09st of December 2007 for comparison purposes. According to experimental studies between 2006 and 2007 years, yearly average wind velocity is found to be 3.21 m/s at 30 m height and capacity factor is estimated to be 14.1% for Enercon E48 (800 kW) wind turbine. According to these results, the mean wind speed does not provide economical electricity production from the wind energy. © 2010 Elsevier Ltd. All rights reserved.
Ozgener L.,Celal Bayar University
Renewable and Sustainable Energy Reviews | Year: 2011
During the last three decades, a number of studies have been conducted by various investigators in the design, modeling and testing of earth to air heat exchanger (EAHE) systems. This paper reviews the studies conducted on the experimental and analytical analysis of EAHE systems in Turkey and around the world as of the end February 2011. The studies undertaken on the EAHE systems are categorized into two groups as follows: (i) open loop for space heating/cooling and (ii) closed loop for space heating/cooling systems. This paper investigates the studies on EAHEs, also known underground air tunnel systems. © 2011 Elsevier Ltd. All rights reserved.
Noyan O.F.,Celal Bayar University
International Journal of Hydrogen Energy | Year: 2011
Hydrogen has a considerable potential for becoming a major factor in speeding the transition of our carbon-based global energy economy ultimately to a clean, renewable and sustainable economy. The development of hydrogen production, transportation-storage and utilization technologies can play a central role in addressing growing concerns over carbon emissions and climate change, as well as the future availability and security of energy supply. However the widespread use of hydrogen may have unknown environmental effect due to increased anthropogenic emissions of molecular hydrogen and other gases to the atmosphere, through production, transportation-storage and utilization processes. It is recognized that hydrogen participates in stratospheric chemical cycles of H2O and various greenhouse gases, and a substantial increase in its concentration might lead to changes in equilibrium concentration of constituent components of the stratosphere. More accurate modeling of the stratospheric processes as well as better understanding of several other factors such as hydrogen uptake in soil and its effect on microbial communities is required to assess potential adverse effects of hydrogen economy. It is critical for us to understand the potential adverse effect of widespread use of hydrogen and take necessary actions to understand and prevent its possible environmental impacts. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Bayca S.U.,Celal Bayar University
Separation and Purification Technology | Year: 2013
Two leaching methods were used to study colemanite leaching reactions. First, the conventional acid leaching method was performed using a glass reactor at atmospheric pressure, leaching in a water bath. Second, microwave acid leaching was carried out using the glass reactor in a modified microwave oven. The characterization of ground colemanite was determined by X-ray diffraction (XRD) analysis, X-ray Fluorescence (XRF) analysis and chemical analysis. An investigation was made of the influence of the solid/liquid ratio, stirring speed, acid concentration, microwave power, reaction time and reaction temperature on the leaching recovery of boron oxide. The results of the conventional acid leaching (CVAL) method were compared to the microwave leaching (MWAL) method. The crystallization of gypsum was investigated with regard to obtaining high-purity boric acid at different acid concentrations using microwave leaching, in which all of the calcium ions in the liquid phase were incorporated into the gypsum crystals. The optimum leaching efficiency for the CVAL and MVAL methods was 99.82% and 99.9% respectively. © 2012 Elsevier Ltd. All rights reserved.
Gultekin Sinir B.,Celal Bayar University
Journal of Fluids and Structures | Year: 2013
In this study, the post-divergence behavior of fluid-conveying pipes supported at both ends is investigated using the nonlinear equations of motion. The governing equation exhibits a cubic nonlinearity arising from mid-plane stretching. Exact solutions for post-buckling configurations of pipes with fixed-fixed, fixed-hinged, and hinged-hinged boundary conditions are investigated. The pipe is stable at its original static equilibrium position until the flow velocity becomes high enough to cause a supercritical pitchfork bifurcation, and the pipe loses stability by static divergence. In the supercritical fluid velocity regime, the equilibrium configuration becomes unstable and bifurcates into multiple equilibrium positions. To investigate the vibrations that occur in the vicinity of a buckled equilibrium position, the pseudo-nonlinear vibration problem around the first buckled configuration is solved precisely using a new solution procedure. By solving the resulting eigenvalue problem, the natural frequencies and the associated mode shapes of the pipe are calculated. The dynamic stability of the post-buckling configurations obtained in this manner is investigated. The first buckled shape is a stable equilibrium position for all boundary conditions. The buckled configurations beyond the first buckling mode are unstable equilibrium positions. The natural frequencies of the lowest vibration modes around each of the first two buckled configurations are presented. Effects of the system parameters on pipe behavior as well as the possibility of a subcritical pitchfork bifurcation are also investigated. The results show that many internal resonances might be activated among the vibration modes around the same or different buckled configurations. © 2012 Elsevier Ltd.
Sabikoglu I.,Celal Bayar University
Journal of Alloys and Compounds | Year: 2013
Sr3B2SiO8 host material doped with separately Eu3+, Dy3+ synthesized by conventional solid state synthesis methods at 1100 °C. According to the results of XRD, samples have both of the Sr3B2SiO8 phase and the SrSiO3 phase (Multi-phase MP). Although there is significant amount of impurity concentration, expected energy transitions were obtained from the samples which are doped with Eu3+ and Dy3+. Both samples were performed to the radioluminescence (RL) and photoluminescence (PL) measurements. Measurement results, they were both in harmony with each other. Eu: Sr3B2SiO8 (MP) phosphor has 5D0 → 7Fj (j = 0, 1, 2, 3 and 4) transitions and Dy: Sr3B2SiO8 (MP) phosphor has 4F9/2 → 6HJ (j = 9/2, 11/2, 13/2 and 15/2) transitions. Dy:Sr3B2SiO8 (MP) phosphor synthesized by conventional solid state synthesis method and the RL and PL properties were examined for the first time. © 2012 Elsevier B.V. All rights reserved.
Ozgener L.,Celal Bayar University
Renewable and Sustainable Energy Reviews | Year: 2012
The purpose of this survey is about to analyze the heating coefficient of performance (COP) of geothermal district heating systems. Actual system data are taken from the Salihli GDHS, Turkey. The collected data are quantified and illustrated in tables, particularly for a reference temperature for comparison purposes. In this study, firstly energy and COP analysis of the GDHSs is introduced and then Salihli GDHS coefficient of performance results is given as a case study. Moreover, this paper offers an interesting empirical study of certain geothermal systems. © 2011 Elsevier Ltd. All rights reserved.
Ergonul B.,Celal Bayar University
Food Control | Year: 2013
Relationships among the main food safety concerns and food consumption habits of 600 consumers living in Manisa City center, Turkey were evaluated. Respondents were interviewed face-to-face by a structured questionnaire. Sixty six questions under different groups (demographics of respondents, food safety perceptions, and awareness of food-borne illnesses, contaminants of foods and hazards, sources of food safety information, confidence in food safety authorities, food handling and safety practices at homes) were asked in the interview. Data obtained from the study indicated the need for much more consumer education regarding safe food handling practices in the domestic environment. Food handling practices and food safety are of public concern, and action is required to prevent the food-borne illnesses. It was seen that, TV and radio programmes are important media for sharing the knowledge of food safety with consumers. © 2013 Elsevier Ltd.
Yukselen-Aksoy Y.,Celal Bayar University
Applied Clay Science | Year: 2010
This paper reports the findings of experimental studies on two natural zeolitic soils. Engineering properties (e.g., grain size, specific gravity, compressibility, hydraulic conductivity, swelling behavior and shear strength) were determined in order to assess their suitability for geotechnical and geoenvironmental applications. The two zeolite-rich tuff samples investigated were mainly composed of clinoptilolite. The results show that the cation exchange capacities are 60.5 and 57.2. mEq/100. g, which are below the theoretical reported values. Compression index values obtained reveal that the zeolitic soils are not highly compressible. The modified free swell indexes of the zeolitic samples are around 2.0, suggesting that they have low swelling potential. The drained residual friction angles indicate that the zeolitic soils have relatively high internal friction angles (34° and 36.5° for Z-1 and Z-2, respectively). Based on the results obtained, it was concluded that zeolites are mechanically stable materials that are suitable for embankment materials and landfill liner applications. © 2010 Elsevier B.V.
Kalyoncu F.,Celal Bayar University
Journal of medicinal food | Year: 2010
Antimicrobial and antioxidant activities of mycelia obtained from 10 wild edible mushrooms-Armillaria mellea, Meripilus giganteus, Morchella costata, Morchella elata, Morchella esculenta var. vulgaris, Morchella hortensis, Morchella rotunda, Paxillus involutus, Pleurotus eryngii, and Pleurotus ostreatus-were investigated. For determination of antimicrobial activities of these mushrooms, ethanol extracts were examined with 11 test microorganisms by the agar well diffusion method. P. ostreatus and M. giganteus were the most active species against both bacteria and yeast. Antioxidant properties of ethanol extracts were studied by the 1,1-diphenyl-2-picrylhydrazyl free radical scavenging method. Among the mushroom extracts, M. elata showed the most potent radical scavenging activity. This research has shown that these 10 wild macrofungi have potential as natural antioxidants and antibiotics.