Yazar "Bayrakci, Asiye Gul" seçeneğine göre listele

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    Influence of thermal and alkali pretreatment to solubilisation and biomethane production of garden waste
    (Inderscience Enterprises Ltd, 2015) Arici, Sefik; Ersoz, Ozben; Bayrakci, Asiye Gul; Eryasar, Ahmet; Kocar, Gunnur
    The objectives of this study were to determine the effect of pretreatment to the garden wastes under thermal and alkali conditions and to evaluate biochemical methane potential. In thermal pretreatment different temperatures and application times were examined and solubilisation improved by heating. Soluble chemical oxygen demand (sCOD) concentration upgraded by increasing temperature with different time intervals. 90 degrees C and 2-hour pretreatment time enabled maximum solubilisation of COD for garden waste. For carbohydrate solubilisation, 50 degrees C and 8-hour application time showed the best performance. Alkali pretreatment also stimulated solubilisation of COD, carbohydrates and total nitrogen which concluded with biochemical methane potential tests. Alkali pretreatment (1% NaOH) increased the overall biomethane production by about 30% compared to the garden wastes without pretreatment. According to this study, the highest methane yield (397.7 ml/gVS) was obtained with 1% NaOH pretreatment to garden waste without pH adjustment.
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    Second generation bioethanol (SGB) production potential in Turkey
    (Wiley-Blackwell, 2014) Bayrakci, Asiye Gul; Kocar, Gunnur
    Energy demand is increasing by the years. Population's needs and technological investments bring the new approach about generating energy. It is considered that fossil fuels will not be able to respond to all energy requirements after approximately 150years. Turkey imports nearly all of its petroleum and so this causes major economic problems. Turkey, as a major cereal producer, has a huge potential to grow energy crops and other cellulosic biomaterials and can obtain plant's residues, which are suitable to produce second generation bioethanol (SGB). With domestic production, bioethanol can reduce the dependence of petroleum for Turkey, and greenhouse gas emissions can be decreased. Taking into account Turkey's situation in fuel-oil consumption, costliness of gasoline and environmentally hazardous specification of fossil fuels, bioethanol gains more importance and increases in value. Especially, SGB production is rising. Foodstuffs are valuable, and producing ethanol from directly those materials can cause a crisis in Turkey because lignocellulosic bioethanol is becoming prominent. In this regard, bioethanol production in Turkey becomes a major alternative to petroleum and may be a key to new and clean energy source. Copyright (c) 2013 John Wiley & Sons, Ltd.
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    Second-generation bioethanol production from water hyacinth and duckweed in Izmir: A case study
    (Pergamon-Elsevier Science Ltd, 2014) Bayrakci, Asiye Gul; Kocar, Gunnur
    Water hyacinth and duckweed are both aquatic plants that live in clean water and wastewater. They have excellent filtration ability of nitrogen and supply oxygen to water while cleaning it up. The vegetative reproduction rates of these two plants are really high and it is about 8 days that of duplication time. Because of these features, water hyacinth and duckweed are useful for wastewater treatment. Also production of second-generation bioethanol from these plants is proper due to their cellulose ratios and carbohydrate potentials. In this study, the process of bioethanol production from water hyacinth and duckweed was studied by taking into account the potential of cultivation values and usability in wastewater treatment procedures in Izmir. Different microorganisms, yeast and bacteria (Saccharomyces cerevisiae, Pichia stipitis, and Clostridium thermocellum) have been considered to identify the best process of ethanol production, considering Turkey's policy regarding biofuels. (C) 2013 Elsevier Ltd. All rights reserved.
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    Utilization of renewable energies in Turkey's agriculture
    (Pergamon-Elsevier Science Ltd, 2012) Bayrakci, Asiye Gul; Kocar, Gunnur
    Agriculture is still the occupation of the majority of Turkish people, despite the share of industry and services rising constantly. In terms of agricultural lands, Turkey is also one of the largest countries in the world. Fruits and field crops make up for the most of vegetable products, wheat being the leading crop. Turkey has a high trade surplus with the EU-27 (1.5 billion Euros in 2009) mainly due to exports of edible fruits and nuts, preparations of fruit and vegetables. The aim of this study is to investigate the utility of renewable energies for agricultural activities. In this concept, solar energy, biomass energy, wind energy, geothermal energy and hydropower are discussed by application examples performed in Turkey. In conclusion, proposals and recommendations are given as alternative energy instead of fossil energy sources. (C) 2011 Elsevier Ltd. All rights reserved.