20 research outputs found

    Mikroalgal ve anaerobik mikrobiyel kültürlerin kullanımı ile entegre besiyer madde giderimi, sera gazı mitigasyonu ve biyo-yakıt ve biyo-ürün eldesi

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    TÜBİTAK ÇAYDAG15.08.2015Mikro algal kültürlerin kullanımı ile önemli bir sera gazı olan CO2’in mitigasyonu çok yeni bir araştırma alanıdır. Mikro algal kültürler ile besiyer madde giderimi ve atık mikro algal biyokütleden biyogaz, hidrojen ve gübre eldesi çeşitli araştırmalara tek başına ya da birlikte konu olmuş uygulamalardır. Ancak, bu projenin konusunu oluşturan mikro algal ve anaerobik mikrobiyel kültürlerin entegre besiyer madde giderimi, sera gazı mitigasyonu ve biyo-yakıt ve biyo-ürün eldesi için birlikte kullanıldığı entegre bir biyoproses konfigürasyonun geliştirilmesi özgün bir yaklaşımdır. Bu inovatif konfigürasyon sadece atık su arıtımı ve CO2 mitigasyonu gibi önemli atık yönetimi sorunlarına bir katkıda bulunmakla kalmayacak, biyoyakıt (biyogaz ve biyohidrojen) ve biyoürün (gübre) eldesi de sağlayabilecektir. Bu projenin en önemli çıktısı hem evsel hem de endüstriyel atık suların atık CO2 kaynakları (örneğin endüstriyel baca gazları) ile birlikte arıtılabilmesini sağlayan özgün bir biyoteknolojik proses konfigürasyonunun geliştirilmesi olacaktır. Bu sürece paralel olarak sağlanacak olan biyoyakıt ve biyoürün eldesi, sadece atık valorizasyonuna değil, sürdürülebilir atık yönetimine de önemli bir örnek oluşturabilecektir. Atık sulardan azot ve fosforun %90-100 arasında değişen verimle giderimi, fotobiyoreaktörlerde sağlanan 0,16-0,26 g/L.gün CO2 tutma hızı, mikro algal biyokütleden elde edilen metan verimi (249 mL CH4/g TUKM), hidrojen verimi (2,47 mL H2/g TUKM) ve detayları bu raporda sunulan projemizin diğer sonuçları hipotezimizi destekler bir ilk adım niteliğindedir. Diğer bir deyişle, mikro algal ve anaerobik mikrobiyel kültürlerin entegre besiyer madde giderimi, sera gazı mitigasyonu ve biyo-yakıt ve biyo-ürün eldesinde birlikte kullanımı olasıdır. Bu üç farklı amaca aynı anda hizmet edecek olan bir inovatif biyoproses konfigürasyonunun optimizasyonu çalışmalarımızın bundan sonraki aşamasını oluşturacaktır.The mitigation of CO2 which is an important greenhouse gas by using microalgal cultures is a very new research area. Nutrient removal by microalgal cultures and anaerobic digestion of waste microalgal biomass and subsequent biogas, biohydrogen and fertilizer production were relatively investigated in the past. However, the research on these areas concentrated on only one or two of these tasks. Therefore, the integrated bioprocess configuration which is investigated in this project to provide integrated nutrient removal, greenhouse gas mitigation and bio-fuel and fertilizer production by using both microalgal and anaerobic microbial cultures is an innovative approach. This innovative configuration will not only contribute to nutrient removal from wastewaters and CO2 mitigation but also generate bio- fuels (biogas, biohydrogen) and bio-products (fertilizer). The impact of this project will be a cost-efficient biotechnological process configuration for the treatment of both domestic and industrial wastewaters as well as waste CO2 sources such as flue gas. Moreover, the parallel bio-fuel and bio-product generation will be a good example of waste valorization and sustainable waste management approach. Nitrogen and phosphorus removal from wastewaters with 90-100% efficiency, achievement of significant CO2 mitigation rates (0,16-0,26 g/L.day) in photobioreactors, methane production from microalgal biomass with a yield of 249 mL CH4/g VS, dark fermentative hydrogen production with a yield of 2.47 mL H2/g VS and other results of our project which are presented in this report not only support our initial hyphothesis but also constitute the first step toward its realization. In other words, an integrated approach enabling nutrient removal, greenhouse gas mitigation and bio-fuel and fertilizer production by using microalgal and anaerobic cultures is possible. Optimization of an inovative bioprocess configuration which will serve for all these three objectives will be the next phase of our research

    2011] Wages, Implicit Contracts, and the Business Cycle: Evidence from a European Panel, CEPS/INSTEAD Working Paper

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    ► We study the cyclical co-movement of hours and wages in Europe. ► Their behavior is consistent with the presence of implicit insurance contracts. ► The nature of the contracts depends on the country's labor market institutions. ► The elasticity of labor supply is much smaller compared to the U.S. labor market. a b s t r a c t a r t i c l e i n f o We study the joint behavior of hours and wages over the business cycle in a unique panel of 13 European countries, and document significant history dependence in wages. Workers who experience favorable market conditions during their tenure on the job have higher wages, and work fewer labor hours. Unobserved differences in productivity, such as varying job quality, or match-specific productivity are not likely to explain this variation. The results instead point to the importance of contractual arrangements in wage determination. In economies with decentralized bargaining practices, such arrangements resemble self-enforcing insurance contracts with one-sided commitment (by the employer). On the other hand, in countries with strong unions and centralized wage bargaining, wage behavior is better approximated by full-commitment insurance contracts. The co-movement of hours and wages further confirms a contractual framework with variable worker hours. Despite the strong prevalence of contracts in Europe, however, the elasticity of labor supply is considerably smaller compared to the U.S. labor market

    Tıbbi İlaç Ve Kozmetik Ürünlerinin Dezenfeksiyon Sonrası Dezenfeksiyon Yan Ürünlerine Dönüşümü

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    Yasalar ile içme suyu konsantrasyonuna limitler getirilmiş olan temel trihalometan (THM), haloacetic asitler (HAA), chlorite ve bromate gibi yan ürünlerin dışında 600’ün üzerinde dezenfektasyon yan ürünü potansiyeli olan kimyasal vardır Bu çalışma bir grup endokrin bozucular ve tıbbi ilaç ve kozmetik ürünlerinin dezenfektasyon sonucu olusabilecek toksisite etkilerine ve potansiyel dezenfektasyon yan ürünü olan N-nitrosodimethylamine (NDMA) oluşumunu inceleyecektir. Araştırma kapsamında kullanılacak 8 endokrin bozucular ve tıbbi ilaç ve kozetik ürünlerinden (Ranitidine, Doxylamine, Diltiazem, Sumatriptan, Caffeine, Diclofenac, Atrazine ve Sulfamethoxazole) herbiri herbiri ayrı ayrı 2,5mg/L monochloramine konsantrasyonu içeren tampon solüsyon içinde 24 saat orbital karıştırıcıda bekletildikten sonra oluşan NDMA konsantrasyonları Gas Chromatography/Mass Spectrophotometry (GC/MS) cihazı ile ölçülecektir. NDMA dışındaki oluşabilecek potansiyel dezenfeksiyon yan ürünlerinin tespiti içinse in vitro biyodeney methodları kullanılacaktır. Bu proje çıktılarının ilki içme suyundaki endokrin bozucular ve tıbbi ilaç ve kozetik ürünlerininin dezenfeksyon sonucu transformasyon geçirmesi durumunda yeni oluşan organik maddelerin insan sağliğına potansiyel bir risk oluşturup oluşturmadığını gösterecektir. Bu sonuçlar potensiyel risklerin daha detaylı incelnmesi yolunda araştırma projelerine yön gösterecek ve risklerin azaltılmasına yönelik çalışmalara yardımcı olacaktır

    Çevrimiçi öğrenme öğrencilerinin çevrimiçi öğrenmeye hazır bulunuşluk düzeyleri, algıladıkları yapı ve etkileşim arasındaki ilişki

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    Araştırmada çevrimiçi öğrenme öğrencilerinin çevrimiçi öğrenmeye hazır bulunuşluk düzeyleri, çevrimiçi öğrenme ortamında algıladıkları yapı ve etkileşim arasında ilişki olup olmadığı belirlenmeye çalışılmıştır. Araştırmada kesitsel tarama modeli temel alınarak gerçekleştirilmiştir. Araştırma Sakarya Üniversitesi çevrimiçi öğrenme lisansüstü programlarında öğrenim gören öğrencilerden gönüllü olarak katılan 320 öğrenciyle yürütülmüştür. Araştırmada katılımcılara çevrimiçi öğrenmeye hazır bulunuşluk, algılanan yapı ve etkileşimden oluşan bir anket uygulanmıştır. Araştırmanın hipotezleri, yapısal eşitlik modellemesi ile test edilmiştir. Araştırma sonunda çevrimiçi öğrenme öğrencilerinin çevrimiçi öğrenmeye hazır bulunuşluğun, öğrenme ortamlarındaki etkileşimleriyle pozitif, algılanan yapıyla ise negatif ilişkili olduğu bulunmuştur. Yine öğrenme ortamında algılanan yapı ile etkileşim arasında negatif bir ilişki olduğu ortaya çıkmıştır. Araştırmada çevrimiçi öğrenmeye hazır bulunuşluğun öğrencilerin öğrenme sonuçlarını etkileyen yapı ve etkileşim değişkenleri açısından önemli olduğu ortaya çıkmıştır

    Relationship between Online Learning Readiness and Structure and Interaction of Online Learning Students

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    Current study tried to determine whether a relationship exists between readiness levels of the online learning students for online learning and the perceived structure and interaction in online learning environments. In the study, cross sectional survey model was used. The study was conducted with 320 voluntary students studying online learning post-graduate programs in Sakarya University. The participants were administered a questionnaire consisting of readiness for online learning, perceived structure and interaction in the study. The hypotheses of the research were tested with structural equation modeling. It was found at the end of the research that online learning students' readiness for online learning was positively related with their interactions in learning environments and negatively related with perceived structure. In addition, there appeared to be a negative relationship between perceived structure and interaction. In the study, it was found that readiness for online learning was important regarding the structure that affects learning results of students and interaction variables

    Sets of alternatives as Condorcet winners

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    We characterize sets of alternatives which are Condorcet winners according to preferences over sets of alternatives, in terms of properties defined on preferences over alternatives. We state our results under certain preference extension axioms which, at any preference profile over alternatives, give the list of admissible preference profiles over sets of alternatives. It turns out to be that requiring from a set to be a Condorcet winner at every admissible preference profile is too demanding, even when the set of admissible preference profiles is fairly narrow. However, weakening this requirement to being a Condorcet winner at some admissible preference profile opens the door to more permissive results and we characterize these sets by using various versions of an undomination condition. Although our main results are given for a world where any two sets – whether they are of the same cardinality or not – can be compared, the case for sets of equal cardinality is also considered. Copyright Springer-Verlag Berlin Heidelberg 2003

    Structural Equation Modeling Towards Online Learning Readiness, Academic Motivations, and Perceived Learning

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    The relationship between online learning readiness, academic motivations, and perceived learning was investigated via structural equation modeling in the research. The population of the research consisted of 750 students who studied using the online learning programs of Sakarya University. 420 of the students who volunteered for the research and filled the scales via the convenience sampling method constituted the research sample. The correlational research model was used in the research. The scales of online learning readiness, academic motivation, and perceived learning were applied to the participants. The relationship among the variables of the research and the research hypotheses for the model were tested via structural equation modeling. It was revealed as a result of the research that the online-learning readiness levels of students predicted their academic motivations directly and their perceived learning indirectly. It was also found that student academic motivations predicted their perceived learning directly. The proposed model was verified in accordance with the data obtained from the research. It was determined as a result of the model obtained from the research that academic motivation is effective in increasing perceived learning in online learning, and increasing readiness is an effective way to increase academic motivation

    Structural Equation Modeling Towards Online Learning Readiness, Academic Motivations, and Perceived Learning

    No full text
    The relationship between online learning readiness, academic motivations, and perceived learning was investigated via structural equation modeling in the research. The population of the research consisted of 750 students who studied using the online learning programs of Sakarya University. 420 of the students who volunteered for the research and filled the scales via the convenience sampling method constituted the research sample. The correlational research model was used in the research. The scales of online learning readiness, academic motivation, and perceived learning were applied to the participants. The relationship among the variables of the research and the research hypotheses for the model were tested via structural equation modeling. It was revealed as a result of the research that the online-learning readiness levels of students predicted their academic motivations directly and their perceived learning indirectly. It was also found that student academic motivations predicted their perceived learning directly. The proposed model was verified in accordance with the data obtained from the research. It was determined as a result of the model obtained from the research that academic motivation is effective in increasing perceived learning in online learning, and increasing readiness is an effective way to increase academic motivatio
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