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61.
Recycling and Oligomerization Activity of Ni/Al Catalyst in a Biphasic System with Ionic Liquids 下载免费PDF全文
Arno Behr Zeynep Bayrak Güner Samli Dilbar Yildiz Vedat Korkmaz Stefan Peitz Guido Stochniol 《化学工程与技术》2017,40(1):196-204
The catalyst decomposition in homogeneously catalyzed reactions is a very important factor that has been studied for the oligomerization of n‐butenes in a system of two liquid phases. A highly active catalyst [NiCl2(PMe3)2] was investigated with an emphasis on the long‐term catalyst activity using N‐methylpyrrole as a buffer. The recycling experiments indicated that this catalyst is viable for five runs. Furthermore, introducing aluminum chloride or an ionic liquid in small concentrations led to increased stability, though fine adjustments were necessary to arrive at optimal results. 相似文献
62.
Screening for and characterization of Lactococcus lactis bacteriophages with high thermal resistance
Zeynep Atamer Jochen Dietrich Mareile Müller-Merbach Horst Neve Knut J. Heller Jörg Hinrichs 《International Dairy Journal》2009,19(4):228-235
Fifty-six Lactococcus lactis phage isolates collected from different German dairies and obtained from a starter culture manufacturer were tested for their heat resistance. About 40% of these isolates resisted treatment at 80 °C for 5 min when they were heated in milk. The most resistant phage isolate, P1532, was collected from sour cream. Plaque-formation was still detectable even after heating at 97 °C for 5 min. The second heat-resistant one, P680, showed some plaque-forming ability after heating at 95 °C for 5 min. Kinetic parameters for the thermal inactivation of these two resistant phages were determined for temperatures ranging from 70 to 97 °C. The inactivation of phage P1532 in skim milk and in buffer medium were found to follow first-order kinetics and did not exhibit tailing, whereas in the inactivation curves of phage P680 tailing was observed. The D-value of P1532 at pasteurization temperature of 72 °C was calculated as 112 min. 相似文献
63.
Fatma Gol Ali Yilmaz Emre Kacar Selin Simsek Zeynep Gizem Sarıtas Cigdem Ture Melek Arslan Muhammed Bekmezci Hakan Burhan Fatih Sen 《Ceramics International》2021,47(15):21061-21068
Today, various studies are carried out to spread the understanding of sustainability. The sustainability of production processes gains importance in corporate areas. In this study, the use of glass waste instead of frit used in glaze compositions in the ceramic industry was evaluated. The chemical and physical properties of glass wastes on samples were examined. The glaze formulations were prepared using 3%, 5%, and 8% by weight of glass waste instead of frit. Glass wastes were added to glaze compositions and 12 different glaze formulation studies were carried out. Transparent, Opaque, and Matte test glazes were prepared with glass waste added glaze formulations, and these glazes were applied to ceramic bodies. SEM (scanning electron microscope) analysis of standard glaze and glass waste added glazes was performed to determine the microstructural and morphological characterizations. Also, surface whiteness, brightness, L*a*b values, glaze flows, harcort test results, and final water absorption values were compared. As a result of the studies, it has been determined that it is appropriate to use 3% glass waste by weight instead of the frit in the production of ceramic tableware. 相似文献
64.
Fully dense boron carbide-silicon carbide composites were successfully produced by spark plasma sintering method at 1950 °C under 50 MPa applied pressure. The effect of dry and wet mixing methods on uniformity was observed. Density, elastic modulus, microstructure, Vickers hardness and fracture toughness were evaluated. The results showed that dry mixing did not provide uniformity on composites properties. On the other hand wet mixing provided uniformity in microstructure and consistency in material properties. The hardness of the sample containing 50 wt% B4C was measured to be 30.34 GPa hardness value was found at 50 wt% B4C content sample. The increase in the B4C content of the composites decreased the Young's modulus, shear modulus, bulk modulus and fracture toughness. The highest values were found at 10 wt% B4C sample which were 415 GPa (E), 177 GPa (G), 209 GPa (K), and 2.89 MPa m1/2 fracture toughness (KIc). 相似文献
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Mustafa Tuzen Yunus Emre Unsal Mustafa Soylak Zeynep Akkirman Baki Hazer 《International Journal of Food Science & Technology》2013,48(11):2384-2390
A separation and preconcentration procedure based on solid‐phase extraction of Cu(II) and Pb(II) as their Sudan III chelates on polyhydroxybutyrate‐b‐polydimethyl siloxane (PHB‐b‐PDMS) block copolymer disc has been established. Various analytical parameters including pH, amount of Sudan III, eluent type and volume, sample volume, flow rates were optimised. The effects of concomitant ions on the retentions of the analyte ions on PHB‐b‐PDMS disc were also examined. The detection limits for Cu(II) and Pb(II) were found to be 2.3 and 4.9 μgL?1, respectively. Preconcentration factor was found to be sixty. Relative standard deviation was found to be 5%. The accuracy of the method was confirmed by analysing certified reference materials (TMDA 54.4 fortified lake water and NIST 1515 Apple leaves). Optimised method was applied to determine the analyte ions in various water and food samples from Turkey. 相似文献
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When ferric ions are substituted for ferrous ions in Fenton’s reagent, the reactions which occur are called Fenton‐like reactions. This study describes the relative efficiency of Fenton (with ferrous ions) and Fenton‐like (with ferric ions) reactions for the degradation of a basic dyestuff, CI Basic Yellow 51, in aqueous solution. Comparisons were made on the basis of the observed reductions in chemical oxygen demand and visible absorption of the dye solutions at optimum reaction conditions. It was found that the Fenton process with 2.63 mm ferrous ion and 39.96 mm hydrogen peroxide at the optimum pH (3.0) eliminated 92.2% of chemical oxygen demand and 98.9% of colour in 22 min, whereas 43.2% of chemical oxygen demand and 64.6% of colour was eliminated by the Fenton‐like process within the same time period, but at pH 4. The efficiency of the latter was significantly improved (to 96.6% removal of colour and 99.7% removal of chemical oxygen demand) by an increase in temperature of 35 °C (from 15 to 50 °C), while no improvements were observed in the efficiency of the Fenton process by temperature elevations. 相似文献
70.
Hans-Josef Altenbach Rachid Ihizane Bernd Jakob Karsten Lange Manfred Schneider Zeynep Yilmaz Sukhendu Nandi 《Journal of surfactants and detergents》2010,13(4):399-407
The reaction of hydroxycarboxylic acids, such as citric, malic and tartaric species with an excess of fatty acid chlorides
produces the corresponding O-acylated hydroxycarboxylic anhydrides in one step and in a near quantitative yield. These molecules are excellent electrophiles
which react readily with a variety of nucleophiles including alcohols, diols and polyols. Their reaction with triethylene
glycol and triethylene glycol monomethyl ether leads to two series of novel anionic surfactants, which are unsymmetrical gemini
surfactants. The determination of their properties (CMC, foaming, HLB) revealed that these molecules are—depending on the
chain length of the fatty acid—excellent emulsifiers, and that they also display interesting antimicrobial activity. These
novel functional surfactants are of interest for applications in food and personal care products and for the formulation of
pharmaceuticals. 相似文献