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101.
S. Aliyev B. Koralay N. Sonel S. Koc S. İmer 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2013,35(7):591-605
Abstract Samples collected from the bituminous shales in the Eocene Tokmaklar formation are the material of this study. Distribution of organic material and trace metals in the shale samples and their concentration levels and correlations were evaluated. Organic carbon content of the bituminous shales is between 0.59 and 15.89% (averaging as 4.86%). The type of organic material is 100% amorphous material (kerogen type is Type I and Type II) and it has a potential to produce oil. Trace metal enrichment levels were determined on the basis of average shale concentration in the earth crust. These levels are divided into two groups. Mo (1.98–2.64), Cu (1.27), As (1.59–8.83), and Sr (2.58–2.75) in bituminous rocks show enrichment character while Pb, Zn, Ba, and Co metals do not display any enrichment. Moreover, comparison with the average values of these metals in seawater and living organisms yield enrichment coefficients of 86.17–386.000 (with respect to seawater) and 4.59–1,723.5 (with respect to living organisms). 相似文献
102.
Ayhan Mergen Yeliz İpek Hülya Bölek Mustafa Öksüz 《Journal of the European Ceramic Society》2012,32(9):2001-2005
In this study, nano sized zinc borate powder with a formula of 4ZnO·B2O3·H2O was synthesized using 2ZnO·3B2O3·3.0–3.5H2O as a starting chemical which was produced using a wet chemical method. After dissolving 2ZnO·3B2O3·3.0–3.5H2O in an ammonia solution, the clear solution was boiled until a white powder formed. The resultant powder was characterized with XRD, FTIR, TGA and TEM. XRD, FTIR and TGA results proved that the powder was belonged to the 4ZnO·B2O3·H2O. Nano composites of 4ZnO·B2O3·H2O–polyvinylchloride (PVC) were produced by injection moulding by adding 1 and 5 wt% zinc borate powders into PVC to enhance its flame retardancy. Limiting oxygen index (LOI) of virgin PVC increased from 41% to 47% and 54% for the 1 and 5 wt% zinc borate added PVC, respectively. Nano zinc borate addition into the PVC does not have considerable negative effect on the mechanical properties of zinc borate–PVC composites even at high amounts of 5 wt%. 相似文献
103.
In this study, we proposed to investigate how the effect of electron-donating methyl ( CH3) group at p-position of amin ( NH2) group in aminophenol (AP) compound affected thermal stability, optical, electrochemical properties, and conductivity measurement. For this reason, we choice 2-AP and 2-amino-4-methylphenol compounds and synthesized phenolic monomers by condensation reactions 4-fluorobenzaldehyde with aromatic amino phenols. Then, these monomers were converted to their polyphenol derivatives by oxidative polycondensation reactions in an aqueous alkaline medium. Structural characterizations were carried out by FTIR, NMR, and size exclusion chromatography. Cyclic voltammetry was used to determine the electrochemical oxidation-reduction characteristics. Optical properties were investigated by UV–vis and fluorescence analyses. Solid state electrical conductivities were measured on polymer films by four-point probe technique using an electrometer. Thermal data of monomer/polymer and polymers were obtained by TG-DTA and DSC techniques, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
104.
The PVA/PVP, PVA/PVP with 5% and 10% chitosan and PVA/PVP-Iodine fibers were produced via electrospinning technique. Their morphological and chemical characteristics were examined with SEM, TGA, FT-IR, viscometer and four-point probe conductivity measurement apparatus. The addition of chitosan increased the viscosity and the electrical conductivity of the polymer. The increase chitosan contents resulted in the diameters of the fibers smaller than expected. This was attributed to the increase in the viscosity of the solution and the electrical conductivity of the resulting fibers. The DSC results show that iodine was efficiently cross-linked with the polymer, forming an amorphous structure. 相似文献
105.
Pınar Çalık Eda Bayraktar Bahar İnankur Elif Ş. Soyaslan Merve Şahin Hatice Taşpınar Eda Açık Remziye Yılmaz Tunçer H. Özdamar 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2010,85(12):1628-1635
BACKGROUND: Effect of pH on recombinant human growth hormone (rhGH) production by Pichia pastoris hGH‐Mut+ was investigated at pH = 4.2, 5.0, 5.5, and 6.0. RESULTS: The highest cell concentration was obtained at pH = 6.0 with 53 g L?1, while the highest rhGH concentration was attained at pH = 5.0 as 0.27 g L?1. Total protease secretion increased with increase in pH and with the cultivation time. Oxygen uptake rate increased with increasing pH up to pH = 6.0, having the maximum value, 37 mmol m?3 s?1, at pH = 5.5. KLa values were similar at all the conditions, having a maximum value of 0.14 s?1 at pH = 5.0. Taking the final rhGH concentration into account, the most favourable pH was 5.0; where AOX1 expression level showed a similar trend to AOX activity profiles, having the highest value of 9.4 × 1010 copy mg?1 CDW at t = 15 h; in parallel to AOX1 expression profile, hGH expression level increased until t = 15 h, with the highest value of 4.0 × 1010 copy mg?1 CDW, where a sharp increase in rhGH concentration was obtained. The expression levels of pep4, prb1 and prc1 genes, responsible from the production of proteinase A, proteinase B and, carboxypeptidase Y, were parallel to each other. CONCLUSION: Since it was shown that pH is a crucial operating parameter in fermentation processes using P. pastoris, keeping pH constant at its determined optimum value, pH = 5.0, during the bioprocess is vital in terms of recombinant protein production. Copyright © 2010 Society of Chemical Industry 相似文献
106.
İlknur Uçak Yesim Özogul Mustafa Durmuş 《International Journal of Food Science & Technology》2011,46(6):1157-1163
The effects of the use of antioxidant technology on the quality of mackerel burgers stored at 4 °C were investigated in terms of sensory, biochemical [thiobarbituric acid (TBA), total volatile basic nitrogen (TVB‐N), peroxide value (PV) and free fatty acids (FFA)] and microbiological analyses [total viable count (TVC)]. Fish meat was divided into three groups; the control (C) without rosemary extract, the second group with 0.4% rosemary extracts (Group A) and the third with 0.8% rosemary extracts (Group B). Results showed that the TVB‐N level did not exceed acceptability limit (30–35 mg 100 g?1) for all groups. TBA value for the control significantly increased from 1.47 to 4.80 MA kg?1 whereas it slightly increased in treatment groups as the storage time increased. Significantly higher PV and FFA (P < 0.05) were obtained from the control group. Rosemary extract, in combination with vacuum pack was effective in controlling the growth of bacteria and biochemical indices. 相似文献
107.
In this study, we investigated the effects of microencapsulation conditions on product quality of pomegranate peel phenolics. Our results indicate an optimum air inlet temperature of 160 °C and 1/1 (w/w) or 1/3 (w/w) for phenolics/maltodextrin ratio. No differences were observed amongst the maltodextrins used for coatings. There were also no statistically significant differences in phenolic content of microcapsules for the storage periods of 90 days at 4 °C (p > 0.05). We also evaluated the resultant microencapsulated phenolics for enrichment of the functional properties of regular ice cream used as model food in our studies. Addition of pomegranate peel phenolics at 0.5 and 1.0% (w/w) showed significant improvement of the antioxidant and α-glucosidase inhibitory activities of the enriched ice creams compared with control sample. Antioxidant activity as EC50 and α-glucosidase inhibitory as IC50 of 1.0% phenolic enriched ice creams were 133.3 and 22.9 μg/mL, respectively. More than 75% of the panellists accepted the phenolic enriched ice creams in sensory evaluation, which lends supports to such products for commercial introduction to the general public with the potential as functional foods. 相似文献
108.
Ramazan Gürkan Halil brahim Ulusoy Mehmet Akay Pinar Bulut Ramazan Gurkan Halil ibrahim Ulusoy Mehmet Akcay Pmar Bulut 《稀有金属(英文版)》2011,30(5):477-487
A novel catalytic kinetic method is proposed for the determination of Se(IV), Se(VI), and total inorganic selenium in water
based on the catalytic effect of Se(IV) on the reduction of Celestine blue by sodium sulfide at pH 7.0 phosphate buffer. The
fixed-time method was adopted for the determination and speciation of inorganic selenium. Under the optimum conditions, the
two calibration graphs are linear with a good correlation coefficient in the range 2–20 and 20–200 μg·L−1 of Se(IV) for the fixed-time method at 30°C. The experimental and theoretical detection limits of the developed kinetic method
were found to be 0.21 and 2.50 μg·L−1 for the fixed-time method (3 min). All of the variables that affect the sensitivity at 645 nm were investigated, and the
optimum conditions were established. The interference effect of various cations and anions on the Se(IV) determination was
also studied. The selectivity of the selenium determination was greatly improved with the use of the strongly cation exchange
resin such as Amberlite IR120 plus as long as chelating agents of thiourea and thiosulphate. The proposed kinetic method was
validated statistically and through recovery studies in natural water samples. The relative standard deviations (RSDs) for
ten replicate measurements of 2, 10, and 20 μg·L−1 of Se(IV) change between 0.35% and 5.58%, while the RSDs for ten replicate measurements of 3, 6, and 12 μg·L−1 of Se(VI) change between 0.49% and 1.61%. Analyses of a certified standard reference material (NIST SRM 1643e) for selenium
using the fixed-time method showed that the proposed kinetic method has good accuracy. The Se(IV), Se(VI), and total inorganic
selenium in lake and river water samples have been successfully determined by this method after selective reduction of Se(VI)
to Se(IV). 相似文献
109.
İlknur Demiral Sevgi Sensöz 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2013,35(12):1159-1168
Fixed-bed pyrolysis biooils of hazelnut (Corylus Avellana L.) bagasse have been identified for their structures. The condensed biooils were analyzed for their properties as fuels and compared with petroleum-derived products. The biooil was analyzed by Fourier Transform infrared spectroscopy (FTIR) and 1H-NMR spectra. The biooils were fractionated into pentane solubles and insolubles. Pentane solubles were then solvent fractionated into pentane, toluene and methanol subfractions by fractionated column chromatograpy. The aliphatic subfractions of the biooils were then analyzed by capillary column gas-liquid chromatography (GC). In addition, the physical properties, higher heating value and elemental analysis of the biooil were determined. The empirical formula of biooil that has a heating value of 34.57 MJ/kg was established as CH1.45O0.33N0.127. Chromatographic and spectroscopic studies on the biooil showed that the oil obtained from hazelnut bagasse could be used as a renewable fuel and chemical feedstock. 相似文献
110.
Blends films based on different ratios of concentrated aqueous solutions of chitosan (CS) and sodium alginate (AG) in the presence of 1% of glutaraldehyde, as a cross‐linking agent for chitosan, were prepared by solution casting and then exposed to gamma irradiation. The formed blends were characterized by IR spectroscopic analysis, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The uptake‐release properties of CS/AG blends, taking ketoprofen as an example for drug, were also investigated. DSC thermograms of CS/AG blends revealed good miscibility was sustained between CS and AG. The water uptake and gel content of CS/AG blends was found to decrease by increasing the ratio of AG in the initial solution. The IR spectra indicated the formation of cross‐linking and hydrogen bonding, while the TGA study showed that the CS/AG blends displayed higher thermal stability than pure CS polymer. Based on Fick's law, it was demonstrated that the main parameters affecting the release of ketoprofen drug from the CS/AG blend hydrogels were composition and pH. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献