115 research outputs found

    PAN-based Pd-doped activated carbon fibers for hydrogen storage: preparation, a new method for chemical activation and characterization of fibers

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    The preparation of ACFs from PAN fibers under various conditions and the method to load Pd on ACFs were described. Chemical activation of the fibers increased the surface areas of the fibers from about 64 m2/g to 381 m2/g. SEM micrographs of Pd-loaded indicated the diameters of the fibers were in the range of 1.0-10.0 mm. Diameters of metallic Pd particles on the fibers changed between 80 nm and 100 nm. 4.5% (by wt) metallic palladium was deposited on the ACFs. This high percentage of palladium deposited on ACFs is useful for hydrogen storage, since Pd-H system is established under a wide range of pressure and temperature

    Carbon nanotube and nanofiber growth on Zn based catalysts

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    In this study, acetylene gas was delivered to a catalyst network consists of NaCl-support and Zn nanoparticles in a temperature range of 500-700°C by means of a chemical vapor deposition (CVD). A principle feature that delineated this CVD study from prior studies lay, first in the method used to support the catalyst and secondly the choice of the catalyst metal. In particular, NaCl was deliberately retained and exploited in subsequent manipulations for the reason that it performed remarkably well as a support medium. The catalytic activity of Zn towards production of CNT/CNFs appeared to be promoted as a result of using molten ionic substrate

    Conversion of low-rank Kilyos coal to nitrogeneous fertilizers

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    The aim of this work is to convert the low-rank Kilyos coal to a material that could be used as a nitrogenous fertilizer. Incorporation of nitrogen into this Kilyos coal was accomplished by oxidative ammoniation, which was a two-step process involving oxidation with nitric acid followed by a treatment by ammonia. The nitrogen content of the raw coal increased from 0.8% to 8.3-9.3% after ammoniation process. Trace element concentrations in the nitro-coal, HA and OAC samples were within the acceptable ranges to be used as nitrogenous fertilizer. Therefore the oxy-ammoniated products could be considered as high-value fertilizers

    Fuel supply chain analysis of Turkey

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    In spite of its natural sources, Turkey depends on other countries in terms of energy production, and a transfer from conventional fossil sources to sustainable energy sources is strongly necessary. Among the sustainable energy sources, biomass is the subject of this study. The characteristics, logistic aspects, environmental aspects, economical, legal and technical aspects are investigated in order to show that the possible biomass co-firing is very important for the construction of economic, sustainable and environmentally friendly energy systems

    Molecular identification of Theileria and Babesia in sheep and goats in the Black Sea Region in Turkey

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    This study was carried out to investigate presence and distribution of Theileria and Babesia species via microscopic examination and reverse line blotting (RLB) techniques in sheep and goats in the Black Sea region of Turkey. For this purpose, 1,128 blood samples (869 sheep and 259 goats) were collected by active surveillance from sheep and goats in different provinces of various cities in the region in the years 2010 and 2011. Smears were prepared from the blood samples, stained with Giemsa, and examined under the light microscope for Theileria and Babesia piroplasms. The genomic DNAs were extracted from blood samples. The length of 360–430-bp fragment in the variable V4 region of 18S SSU rRNA gene of Theileria and Babesia species was amplified using the gDNAs. The polymerase chain reaction products were hybridized to the membraneconnected species-specific probes. A total of 38 animals (3.37 %) including 34 sheep (3.91 %) and 4 goats (1.54 %) were found to be positive for Theileria spp. piroplasms in microscopic examination of smears while Babesia spp. piroplasm could not detected. Infection rates were 34.64 % in sheep, 10.04 % in goats, and totally 28.99 % for Theileria ovis while 0.58 % in sheep and totally 0.44 % for Babesia ovis. However, Theileria sp. OT3 was detected in 2.65 % of sheep and 2.04 % of all animals; besides Theileria sp., MK had 0.58 % prevalence in sheep and 0.77 % in goats, with a total 0.62 % with RLB. Although T. ovis and Theileria sp. MK were determined in both sheep and goats, B. ovis and Theileria sp. OT3 were observed only in the sheep. These results provide the first detailed molecular data for sheep and goat theileriosis and babesiosis in the region

    Trace elements in Turkish biomass fuels: Ashes of wheat straw, olive bagasse and hazelnut shell

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    Ash contents of wheat straw, olive bagasse and hazelnut shells were 7.9%, 3.9%, 1.2%, respectively, which seemed to be within the average values of ash of biomass. The microstructure of ashes included smooth, polygonal, granular and molten drop structures. A large percentage of particles present in ashes are commonly 1–20 lm in size. SEM/EDS analyses performed on the major ash forming elements in different ashes indicated that Si, Ca, K and Mg and P were generally the most abundant species. Trace element levels in ash samples of various biomass types such as hazelnut shell, wheat straw, olive bagasse were analysed using ICP spectroscopy. The elements determined were some of those considered being of great environmental concern such as, Cr, Mn, Fe, Co, Ni, Cu, Zn, Pb. In all of the ashes studied Fe had the highest concentration among other trace elements, Mn was the second element that exhibited higher concentrations. The order of concentration of elements in the ashes from the highest to the lowest values was as follows: Fe > Mn > Zn > Cu > Ni > Cr > Pb > Co

    The Relationship Between the Police and Third Generation Turkish Immigrants in Germany

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    With globalization, countries’ demographic structures have evolved into multicultural societies and this has laid the groundwork for ethnic, religious and cultural conflicts. The conflict process was also the beginning of ongoing integration problems between the majority in a society and minorities with different origins. Third generation Turkish immigrants are nested with a serious identity problem in Germany today. In this a specific example of multiculturalism, Turkish immigrants have adopted spatial segregation as a security method. This is caused by identity security anxiety and reveals another dimension of alienation and exclusion in modern societies with their criminalization by the police. The police are expected to stop conflict by considering the principle of equality and to reduce discrimination to the minimum level. Criminalizing Turkish immigrants and negative experiences in judicial processes, also shape the confidence people have in the police. Finally, immigrants attempt to seek proper security of their own, in the community, where the sense of trust is also alienated. This article discusses the presence of crime and violence as a part of the everyday life of Turkish immigrants, by what means does subjective security become the cause of objective insecurity, and how two different cultures confront each other due to feelings of insecurity towards the police, in the search for security

    Concomitant occurrence of hepatopulmonary hydatid cysts in Turkey

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    Background: We aimed to report the demographic characteristics with diagnosis and treatment methods in patients with concomitant hepatopulmonary hydatid cysts. Methods: Over a ten-year period (from 2002–2020) in Konya, Turkey, surgery was performed on 52 patients with hepatopulmonary hydatid cyst. Main outcome measure(s) were 52 hydatid cysts patients, which had cysts both in the liver and lungs, were investigated regarding their age, gender, cyst localization, suppuration, symptoms, and treatment methods. Results: Seventeen of the patients were males. Their mean age was 39.7±18.8 years. The most common occupation was housewifery. The most common symp tom was coughing and none of the patients with concomitant hepatopulmonary hydatid cysts was asymptomatic. The pulmonary hydatid cysts were mostly en countered in the right lung and the majority of the hepatic hydatid cysts were ob served in the right lobe. The mean hospitalization time of the operated patients was 17.12±6.7 days. Conclusion: In patients with hydatid cysts localized concomitantly in the right lung and subdiaphragmatic area, right thoracotomy for the pulmonary cyst and a transdiaphragmatic approach for the hepatic cyst is a safe, effective, and comforta ble method

    Production of templated carbon nano materials, carbon nanofibers and super capasitors

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    i. Porous carbons are usually obtained via carbonization of precursors of natural or synthetic origin, followed by activation. To meet the requirements, a novel approach, the template carbonization method, has been proposed. Replication, the process of filling the external and / or internal pores of a solid with a different material, physically or chemically separating the resulting material from the template, is a technique that is widely used in microporosity and printing. This method has been used to prepare replica polymers [1,2] metals [3] and semiconductors [4] and other materials [5,6]. Zeolites represent an interesting case for replication processes, because the dimensions of their cages and channels are quite similar to those organic molecules that constitute the replica. If such as nanospace in a zeolite is packed with carbon and then the carbon are extracted from the zeolite framework, one can expect the formation of a porous carbon whose structure reflects the porosity of the original zeolite template. Owing to the disordered and inhomogeneous nature of the starting materials,\ud the resulting carbon has a wide and poorly controlled distribution of pore sizes. Zeolites with three-dimensional pore structures were found to be suitable as templates [7,8], whereas zeolites with one-dimensional structures were not effective [9]. These carbons obtained using zeolite templates with three-dimensional pore structures retained the shapes of zeolite particles, but did not retain their internal periodic structure. ii. Many methods have been proposed for carbon nanofiber (CNF) production, among them, we have chosen chemical vapor deposition (CVD) method for CNF synthesis because of its potential for scaling up the production and low cost[10]. Recent developments showed that alignment, positional control on nanometer scale, control over the diameter, as well as the growth rate of the carbon nanotubes (CNT) and CNFs can be achieved by using CVD[11-13]. Many catalysts supports and metal catalysts were proposed for CNF production through CVD technique. Silica (SiO2) [14], alumina (Al2O3) [15], quartz [16], titania (TiO2) or calcium oxide (CaO) [17] were used as the catalyst support because of their chemical inertness and high-temperature resistance. However, all of these support materials require harsh chemical treatment i.e. concentrated bases (NaOH) or strong acids (HF) to remove them, and these reagents may also damage the carbon nanostructure. Additionally, strong acids and bases are less desirable for large-scale production due to environmental concerns. Our goal in synthesizing CNFs is to achieve a control in tailoring the diameter, and morphology at the same time. We believe that understanding the chemistry involved in the catalyst and nanofiber growth process is the critical point to be able to produce defectless, property controlled CNFs. Thus, knowing the effect of the catalyst on CVD production of carbon nanofibers is very important for producing the desired CNFs. A very unique material, NaCl in the field of catalytic CVD process for carbon materials production, was selected as the support material which provides easy production and easy removal properties to the catalyst system. Together with the support material, the metal catalyst preparation step was differentiated from the conventional wet catalyst methods in which a liquid solution containing the catalyst in salt form is applied to the substrate via spray coating [16,18,19], spin coating [20-22], or microcontact printing [23] as well. The most active metals that were used previously in the catalytic CVD process for carbon materials production were Fe, Co [24], and Ni. The reason for choosing these metals as catalyst for CVD growth of nanotubes was the thermodynamic behavior of the metals at high temperatures, in which carbon is soluble in these metals and this solubility leads to the formation of metal-carbon solutions and therefore the desired carbon nanomaterial formation nucleates. In this study, transition metal based organometallic complex catalysts of Fe, Co, Ni and Cu were synthesized by a new approach of simultaneous synthesis of the support material and the catalyst. Therefore an easy production method for catalyst to use in CVD was developed by using only wet chemistry. iii. Electrochemically conducting polymers (ECPs) are of interest in late years and they are promising materials for realization of high performance supercapacitors, as they are characterized by high specific capacitances, by high conductivities in the charged states and by fast charge-discharge processes. The charge processes pertain to the whole polymer mass and not only to the surface. These features suggest the possibility to develop devices with low ESR and high specific energy and power. However, the long-term stability during cycling is a major demand for an industrial application of ECPs. Swelling and shrinkage of ECPs, caused by the insertion/deinsertion of counter ions required for doping the polymer, is well known and may lead to degradation of the electrode during cycling. This obstacle has been over overcome to some level by using composite materials made of carbon materials such as CNTs or activated carbons with CPs. Carbon material in the bulk both ensures a good electrical conductivity even the CP is in its insulating state and improves the mechanical properties of the electrodes. As mentioned in the earlier chapters, using carbon nanotubes, CPs, or both as composites for the active material of the supercapacitor applications comes with some disadvantages as well as the advantages. CPs although being a promising energy source for the job, lack the flexibility for insertion/deinsertion of the dopant ions resulting in shorter recycling life times than desired. CNTs are the employed to gain more flexibility however whether they are used as active materials solo, or engaged in a composite with a CP, they could not supply enough energy for the job. Therefore, the objective of this study is, to obtain a new material for supercapacitor active material; by depositing a conducting polymer, polypyrrole, on to carbon nanotubes via electropolymerization. By this method, the problem of bulk charging in conducting polymers is aimed to be overcomed. Since the coating is in magnitudes of nanometers, only surface charging will exist, which is desirable for supercapacitor applications

    Biodesulphurized subbituminous coal by different fungi and bacteria studied by reductive pyrolysis. Part 1: Initial coal

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    One of the perspective methods for clean solid fuels production is biodesulphurization. In order to increase the effect of this approach it is necessary to apply the advantages of more informative analytical techniques. Atmospheric pressure temperature programming reduction (AP-TPR) coupled with different detection systems gave us ground to attain more satisfactory explanation of the effects of biodesulphurization on the treated solid products. Subbituminous high sulphur coal from ‘‘Pirin” basin (Bulgaria) was selected as a high sulphur containing sample. Different types of microorganisms were chosen and maximal desulphurization of 26% was registered. Biodesulphurization treatments were performed with three types of fungi: ‘‘Trametes Versicolor” – ATCC No. 200801, ‘‘Phanerochaeta Chrysosporium” – ME446, Pleurotus Sajor-Caju and one Mixed Culture of bacteria – ATCC No. 39327. A high degree of inorganic sulphur removal (79%) with Mixed Culture of bacteria and consecutive reduction by 13% for organic sulphur (Sorg) decrease with ‘‘Phanerochaeta Chrysosporium” and ‘‘Trametes Versicolor” were achieved. To follow the Sorg changes a set of different detection systems i.e. AP-TPR coupled ‘‘on-line” with mass spectrometry (AP-TPR/MS), on-line with potentiometry (AP-TPR/pot) and by the ‘‘off-line” AP-TPR/GC/MS analysis was used. The need of applying different atmospheres in pyrolysis experiments was proved and their effects were discussed. In order to reach more precise total sulphur balance, oxygen bomb combustion followed by ion chromatography was used
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