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Öğe Adsorption of hexavalent chromium from aqueous solutions by bio-chars obtained during biomass pyrolysis(ELSEVIER SCIENCE INC, 2013) Deveci, Huseyin; Kar, YakupIn this study, bio-chars were evaluated as a potential adsorbent for the removal of Cr (VI) ions from aqueous solutions. The effects of some important parameters including initial pH (1.5-7), adsorbent dose (0.2-5 g/L), contact time (5-900 min) and initial Cr (VI) ion concentration (5-75 mg/L) were tested on the removal of Cr (VI) ions from aqueous solution in batch experiments. Maximum adsorption capacities of the tested bio-chars under the certain experimental conditions determined as optimal were 3.53 mg/g for NCBC, 3.97 mg/g for NZCBC and 6.08 mg/g for ACBC, respectively. Results of the kinetic and isotherm modeling studies revealed that the adsorption data fitted well with a pseudo-second order and Langmuir model. In among the tested bio-chars, the bio-char (ACBC) was largely equivalent to activated carbon: AC (9.97 mg/g) in terms of adsorption capacity. All results indicated that the bio-chars had higher adsorption capacity than some chars and activated carbons reported previously, and also that these bio-chars could be used successfully as low-cost adsorbents for the removal of chromium ions from aqueous solutions under the tested experimental conditions. (C) 2012 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.Öğe Antibacterial activity of new [(2-hydroxypropyl)-n-oximino]pyridines(ASIAN JOURNAL OF CHEMISTRY, 2008) Sen, Nejdet; Kar, Yakup; Kurbanov, Sultan; Uyanik, ArzuThe synthesized [(2-hydroxypropyl)-n-oximino]pyridine derivatives has been tested against the pathogenic four Gram-positive bacteria Bacillus cereus (ATCC 11778), Staphylococcus aureus (ATCC 6538), Sarcina lutea (ATCC 934 1) and Streptococs mutans (UCTC 10499) and three Gram-negative bacteria Salmonella typhimurium (1,4,5,12:;: 1,2), Pseudomonas aeruginosa (ATCC 27853) and Escherichia coli (ATCC 29998). Generally, all synthesized compounds (IVa-c) showed strong activity compared to antibiotic drug (cefalexin). However, among this compounds (IVa) showed excellent activity against Bacillus cereus (ATCC 11778), Sarcina lutea (ATCC 9341), Salmonella typhimurium (1,4,5,12:;: 1,2) and Escherichia coli (ATCC 29998) compared to cefalexin.Öğe Antioxidant Activities of Black Cumin (Nigella Sativa L.) Seeds Cultivating in Different Regions of Turkey(Wıley, 2010) Şen, Nejdet; Kar, Yakup; Tekeli, YenerIn this study, the antioxidant activity of the methanolic extracts of the black cumin (Nigella sativa L.) seeds collected from Konya, Isparta, Corum, Burdur, Afyon and Samsun was evaluated using three different methods, specifically the beta-carotene and linoleic acid system, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and reducing power assays. Among the six black cumin samples of different origins, the black cumin sample origins from Konya city showed the most potent radical scavenging activity in each assay, showing 94.59% (at 1 mg/mL) in the beta-carotene bleaching method and 44.44% in the DPPH radical scavenging method (at 0.5 mg/mL). Positive correlations were found between the total phenolic content in the black cumin extracts and their antioxidant activities. The values of their antioxidant activity were either equivalent to or higher than those of positive BHA and BHT controls. These satisfying results lead to expect the use of black cumin seeds as health-promoting ingredients such as dietary supplements and nutraceuticals.Öğe Bazı Aromatik Aminoalkollerin Sentezi ve Yapılarının Aydınlatılması(Selçuk Üniversitesi Fen Fakültesi, 2010) Kar, Yakup; Uyanık, Arzu; Şen, Nejdet; Kurbanlı, SultanBu çalışmada, 1-fenoksi-2,3-epoksipropanın (1) amonyak, izopropilamin, piperidin ve morfolin ile nükleofilik halka açılma reaksiyonundan ilaç sanayinde özel bir ilgiye sahip olan ve asimetrik sentezlerde yaygın olarak kullanılan 2, 3, 4, 5 numaralı ?-aminoalkoller sentezlenmiştir. Fenol ile epiklorhidrinin reaksiyonundan ise çıkış maddesi olarak kullanılan 1 numaralı bileşik sentezlenmiştir. Sentezlenen bileşiklerin yapıları elementel analiz, 1H NMR ve IR gibi spektroskopik yöntemlerle aydınlatılmıştır.Öğe Catalytic pyrolysis of the oily seeds of Styrax officinalis L. for bio-fuels and valuable industrial chemicals(WILEY, 2012) Kar, Yakup; Sen, NejdetThe catalytic pyrolysis of the oily seeds of Styrax officinalis L., which was carried out using two catalysts in a fixed-bed reactor. As a catalyst, expanded perlite was firstly used according to the best current knowledge. Pyrolysis experiments were performed under at 450 degrees C temperature and 25 degrees C/min heating rate. The results showed that both catalyst materials had approximately the same effect on the bio-oil yields. By using the natural zeolite and expanded perlite at a ratio of 30 wt %, the maximum bio-oil yields were achieved as 38.07 wt % and 37.49 wt %, respectively. The oxygen content is important to bio-oil and upgrading oil. High oxygen content causes poor heating value and instability. The use of a catalyst greatly reduced the oxygen content of the bio-oil, such that the 30 wt % of oxygen content for noncatalytic oil decreased to 16.34 wt % and 18.35 wt % with use of natural zeolite and expanded perlite, respectively. Higher heating values (34.84 and 33.48 MJ/kg) and H/C atomic ratios (1.47 and 1.51) for the catalyzed bio-oils were very close to those of petroleum, which are 40 MJ/kg and 1.5:1.9, respectively. In addition, the oxygenated species decreased and also the quantities of alkyl and alkenyl substituted aromatic compounds and paraffinic alkanes in the catalyzed bio-oils were notably higher than those of noncatalyzed bio-oils when using a catalyst. The use of catalysts in the pyrolysis not only increased the yield of bio-oil, but also produced higher quality oil with higher calorific value, lower oxygen content, higher carbon, and hydrogen contents etc. (C) 2011 American Institute of Chemical Engineers Environ Prog, 2011Öğe Çörekotu (Nigella sativa L.) tohumunun doğal antioksidan ve alternatif enerji kaynağı olarak incelenmesi(Selçuk Üniversitesi Fen Bilimleri Enstitüsü, 2008-01-24) Kar, Yakup; Şen, NejdetBu tez çalışmasında, çoğu Avrupa ülkesinde kozmetik, ilaç vb. gibi çok sayıda endüstriyel alanda değerlendirilme imkânı bulan, ülkemizde genelde baharat olarak tüketilen, farklı yörelerde yetiştirilmiş çörekotu tohumlarının antioksidan aktivitelerini belirlemek ve elde edilen sonuçları hem çörekotu tohumları arasında hem de sentetik antioksidan (BHA ve BHT) maddelerle kıyaslamak amacıyla bir dizi antioksidan aktivite belirleme deneyleri yapılmıştır. Yapılan deneyler neticesinde bütün çörekotu tohumlarının sentetik antioksidanlara kıyasla çok güçlü aktivite gösterdikleri ve en yüksek aktivitenin (%94,59) ise Konya yöresinde yetiştirilen numune tarafından gösterildiği belirlenmiştir. Aynı zamanda bu yağlı tohumun çeşitli endüstriyel alanlarda değerlendirilmesi sürecinde oluşan ve direk hayvan yemi olarak kullanılamayan küspenin en ucuz ve en verimli termokimyasal dönüşüm yöntemi (piroliz) ile günümüzde kullanılan yakıtlara alternatif olabilecek sıvı ürün (bio-oil)'e dönüştürülme olanakları araştırılmıştır. Sıvı ürün bakımından optimum şartların (piroliz sıcaklığı, parçacık boyutu, ısıtma hızı, azot gazı akış hızı, alıkonma zamanı ve yoğunlaşma sıcaklığı) belirlenmesi amacıyla sabit yataklı reaktörde piroliz deneyleri yapılmıştır. Yapılan deneyler sonucunda belirlenen optimum şartlarda (450ºC, dp>850 µm, 35ºC/dak, 200 cm3/dak, 30 dak ve ?20ºC) yapılan piroliz deneyleri neticesinde %44,37 verimle H/C= 1,65 ve ısıl değeri 38,22 MJ/kg olan bio-oil elde edilmiştir. Elde edilen bio-oilin yapısı çeşitli spektroskopik ve kromatografik yöntemlerle incelenmiş ve neticede bio-oilin günümüzde kullanılan sıvı yakıtlara hem alternatif yenilenebilir çevre dostu enerji kaynağı olabileceği gibi hem de birçok kimya endüstrisi için kimyasal hammadde girdisi olabileceği belirlenmiştir.Öğe Effect of Modified Phosphate Rock Saturated by Various Salts on Stack Gas Desulfurization in a Fluidized Bed Reactor(Taylor & Francis Inc, 2006) Kar, Yakup; Kar, HaticeIn this work, the suitability of phosphate ore treated with the varied salts such as FeSO4, NaCl, CaCl2, Na2SiO3, and Na2SO4 as an alternative material for limestone and dolomite in flue gas desulfurization has been investigated. Also, the effect of the varied salts on calcination and sulfation of the raw, calcine, and semicalcined phosphate samples has been investigated in a differential fluidized bed reactor at 700-800 degrees C (4 min) in air and 0.3% SO2. It was established that the salts have prominent effects on sulfation and calcination. The changes in the pore structure and products obtained at the end of sulfation were investigated using BET surface area method. In conclusion, it was observed that the sulfation and calcination conversion ratios generally increased when the phosphate rock was treated the varied salts.Öğe Importance of asphaltite deposits in southeastern Anatolia(TAYLOR & FRANCIS INC, 2006) Kar, YakupNative energy sources of Turkey are quite limited, and the country is heavily dependent on the import of primary energy from abroad. The demand for electrical energy has increased very rapidly in Turkey due to the ongoing industrialization process and high population growth. Energy consumption in Turkey has continually increased over the past years and reached 82.2 million tons of oil equivalent (Mtoe) in 2000. This figure is expected to continue to grow and reach 115.2 Mtoe in 2005 and 153.9 Mtoe in 2010. In spite of the availability of all types of energy resources in Turkey, 66% of energy consumption is met with imports, as energy production is not sufficient to satisfy the demand for consumption. The primary energy sources of Turkey are hard coal, lignite, asphaltite, bituminous schist, hydropower, oil, natural gas, nuclear, geothermal, solar, wood, and animal and plant wastes. The required electrical energy of Turkey is primarily met from thermal and hydraulic sources, but, in addition to these, in recent times, asphaltite deposits in the Southeastern Anatolia Region of Turkey, roughly 79.969 million tons are found in the Sirnak and Silopiareas, and are mainly consumed in the residential sectors for heating due to its high calorific value (2876-5536 kcal/kg), are becoming important for Turkey to generate electricity energy. With the aim of this, it is planned to produce electrical energy after 2006 with the asphaltite taken out from Sirnak and Silopi region.Öğe Importance of P-series fuels for flexible-fuel vehicles (FFVs) and alternative fuels(TAYLOR & FRANCIS INC, 2006) Kar, Yakup; Deveci, HuseyinAs engine fuels, the most popular alternative fuels are bioetanol, biodiesel, and hydrogen. Recently, in addition to these, there are intensive researches on methyl-, and ethylalcohols, natural gas, liquefied petroleum gas, P-series, electricity, and solar fuels. Alternative fuels for diesel engines are becoming increasingly important due to diminishing petroleum reserves and the environmental consequences of exhaust gases from petroleum-fueled engines. One of the advantages of P-series is that they are very easy to use. There is no need for any special fuel management because gasoline and P-series can be freely intermixed in any proportion with fuel that is already in the vehicle's fuel tank. So, even if P-series is not available at a particular location, simply fill up with gasoline. These fuels are inexpensive fuels generated by municipal and agricultural wastes. The National Renewal Energy Laboratory (NREL) showed that P-series would be 96% derived from domestic resources and reduce petroleum use by 80% as compared to gasoline. Use of P-series fuels also greatly reduces toxic emissions. P-fuels are economically competitive with gasoline. As of May 2003, the projected retail price for P-series, including all taxes, is $1.49 per gallon, about the same as mid-grade gasoline in a $/mile calculation. There are 3 million cars on the road today that could run on P-series fuels.Öğe Pyrolysis of black cumin seed cake in a fixed-bed reactor(PERGAMON-ELSEVIER SCIENCE LTD, 2011) Sen, Nejdet; Kar, YakupThe black cumin seed cake (BCSC) is a by-product obtained from the black cumin seeds with cold pressing. This by-product can be utilized as a biomass feedstock for conversion to bio-oil with pyrolysis process. The BCSC samples were initially pyrolyzed on a lab-scale pyrolysis system at different values in the ranges of 300-800 degrees C and 0.050-0.300 L min(-1) to determine the effects of operation temperature and N-2 flow rate on the yields on products, respectively. Then, the bio-oil in the highest yield (wB = 44.37%) which was obtained at pyrolysis final temperature (450 degrees C) temperature, heating rate (35 degrees C min(-1)) particle size (dp > 850 mu m), and sweeping flow rate of 0.200 L min(-1) was characterized by Fourier Transform infra-red (FT-IR) spectroscopy, gas chromatography/mass spectrometry (GC-MS) and column chromatography. Consequently, it was shown that the operating temperature and N-2 gas flow rate parameters were effective on the product yields. Also, the important some physico-chemical properties of the pyrolytic oil obtained in high yield were determined as the calorific value of 38.48 MJ kg(-1), the empirical formula of CH1.651O0.105N0.042S0.001, the rich chemical content containing many different chemical groups, and the density of 970.25 kg m(-3), and the viscosity of 63.42 mm(2) s(-1). Based on the determined properties of the pyrolytic oil, it was decided that the use of pyrolytic oil derived from the BCSC may possible be for the production of the alternative liquid fuels and finely chemicals after the necessary improvements. (C) 2011 Elsevier Ltd. All rights reserved.Öğe Removal of Cr (VI) from aqueous solution by pyrolytic charcoals(ELSEVIER SCIENCE BV, 2016) Altun, Turkan; Kar, YakupBio-chars produced by the pyrolysis of walnut shells at 450 degrees C (BC450) and theco-pyrolysis of walnut shells and 20 wt% tar sand (BCTS20) at the same temperature, were investigated as potential adsorbents for the removal of Cr(VI) ions from aqueous solutions using batch experiments. The BCTS20 has more abundant surface functional groups than BC450. The Cr(VI) removal percentages under optimal conditions were 80.47and 95.69% for BC450 and BCTS20, respectively. Langmuir, Freundlich and D-R models were used to fit the adsorption isotherms and the Langmuir model described the adsorption isotherms best. The adsorption of Cr(VI) was by a chemical process dominated by ion-exchange, electrostatic attraction and chelation. The maximum Langmuir adsorption capacities were 36.55 and 49.76 mg per g of BC450 and BCTS20, respectively. The maximum Langmuir adsorption capacity of BCTS20 is comparable to that of some reported commercial activated carbons.Öğe Synthesis and Properties of Composites of Oligoazomethine with Char(WILEY, 2012) Ozaytekin, Ilkay; Kar, YakupConjugated aromatic oligo(azomethine) derivatives (oligo-AMs) were prepared by the condensation of terephtaldehyde 4,4'-diformylbiphenyl bis(4-formylphenyl) ether and p-phenylene diacrolein with 1,4-diaminobenzene at room temperature. The structures of the synthesized oligomers were characterized by FTIR, H-1 NMR, TGA-DTG, UV-vis absorption spectra, and elemental analyses. Additionally, in this study, the oligomer composites were obtained using the carbon material (char) derived from the 450 degrees C pyrolysis of waste polyethylene terephthalates. The conductivity measurements of the produced composites were determined at 24-h periods by doping with iodine vapor. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123:815-823, 2012Öğe Usability of Terebinth (Pistacia Terebinthus L.) Fruits as an Energy Source for Diesel-Like Fuels Production(PERGAMON-ELSEVIER SCIENCE LTD, 2012) Kar, Yakup; Şen, Nejdet; Deveci, HüseyinThis study examined the effects of varying pyrolysis parameters, including final temperature, heating rate, particle size, and nitrogen flow rate, on the yields of terebinth as a source of bio-oil. The maximum bio-oil yield of 58.99 wt.% was almost equal to diesel fuel in terms of its major fuel properties (H/C = 1.73, 38.50 MJ/kg, 0.954 g/cm(3), and flash point of 59 degrees C). The GC MS and H-1-NMR analysis results showed that bio-oil predominantly comprised aliphatic hydrocarbons with high heating value and other valuable compounds with potential added value. The results show that the bio-oil can be used as a feedstock for the production of the diesel-like fuels or refined chemicals.