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.
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.
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.
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.
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.