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61.
A mixed microbial culture degraded a mixture of benzoate (863 mg/L), 3-chlorobenzoate (3-CB) (69.7 mg/L), and pyruvate (244 mg/L) under denitrifying conditions in a chemostat. Biodegradation under denitrifying conditions was stable, complete (effluent concentrations below detection limits), and proceeded without the production of toxic intermediates like chlorocatechols. The addition of oxygen at mass input rates of 6.2%, 15.5%, and 43.9% of the mass input rate of chemical oxygen demand (COD) (337 mg COD/h) did not induce the synthesis of aerobic biodegradation pathways and thus did not disrupt biodegradation. Rather, the oxygen was used as a terminal electron acceptor, displacing a stoichiometric amount of nitrate, leading to microaerobic conditions (dissolved oxygen concentration <0.050 mg/L) in which oxygen utilization and denitrification occurred simultaneously. The reduction of nitrate occurred fully to N2 gas with no accumulation of nitrite, nitrous oxide, or nitric oxide, although the ability of the culture to transfer electrons to the nitrogen oxides decreased as the oxygen input was increased. The anoxic benzoate uptake capability was unaffected by the increase in oxygen addition, but the anoxic 3-CB uptake capability increased, as did the level of benzoyl-CoA reductase in the cells. 相似文献
62.
This work refers to the synthesis of a series of novel chlorinated poly(?-caprolactone) (PCL) for further functionalization of PCL. For this aim, chlorine gas was passed through into the chloroform solution to obtain chlorinated polycaprolactone. The chlorine contents in chlorinated PCL were between 0.9 and 1.6 mol%. The molecular weights of the polymers (M n) changed from 4853 to 9497 g/mol. As the amount of passing chlorine gas increases, the molecular weight of the chlorinated PCL was found to decrease. Pendant chloride groups of PCL were reacted with sodium azide to prepare PCL with pendant azide groups (PCL-N3). Poly-(ethylene glycol) methyl ether (mPEG) was reacted with propargyl chloride to achieve alkynyl mPEG (mPEG-alkyn). Click reaction was then carried out by the reaction between PCL-N3 and mPEG-alkyn to obtain PCL-g-PEG comb-type amphiphilic graft copolymer. Interestingly, SEM images of the PCL-g-PEG comb-type amphiphilic graft copolymers showed the highly microporous structure. The resulting products were characterized by 1H NMR, FT-IR, gel-permeation chromatography, SEM, surface tension, contact angle and water uptake measurements, differential scanning calorimeter and thermogravimetric analyses techniques. 相似文献
63.
Sergey V. Ushakov Alexey Shvarev Timur Alexeev Denys Kapush Alexandra Navrotsky 《Journal of the American Ceramic Society》2017,100(2):754-760
Design, calibration, and operation of a system for drop‐and‐catch (DnC) calorimetry on oxides from temperature above 1500°C are described. This system allows the measurement of heat contents and heats of fusion by drop calorimetry of small (100 mg or less) samples held by containerless levitation at high temperature and dropped in a calorimeter at room temperature. The spheroids, 2‐3 mm in diameter, prepared by laser melting of powders, are aerodynamically levitated in a splittable nozzle levitator and laser heated to the desired temperature monitored by radiation thermometry. The sample is dropped by splitting the nozzle and caught by splittable water‐cooled calorimetric plates at 25°C, which provide complete enclosure of the sample to avoid heat loss by radiation. The drop time is ~0.1 seconds, calorimeter equilibration time after the drop is ~15 minute. DnC experiments are automated with software‐controlled laser power and programmable delay between splitting the nozzle and catching the sample. The fusion enthalpy of Al2O3 measured by DnC calorimeter, 120 ± 10 kJ/mol, agrees well with previously reported values. The system can be used for measurements of fusion enthalpies of refractory oxides amenable to laser heating as well as for splat quenching of oxide melts. 相似文献
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66.
Nazym Akhanova Yerassyl Yerlanuly Didar Batryshev Timur Kulsartov Yevgeniy Chikhray Tlekkabul Ramazanov Ayfer Veziroglu Dmitry Schur Wanli Kang Maratbek Gabdullin 《International Journal of Hydrogen Energy》2021,46(10):7426-7431
In this work, the results of the hydrogen permeability study of a composite film-forming inhibitor are considered. Film-forming inhibitor consists of polyether urethane and synthesized fullerenes C60 and C70 in pure form. Two types of samples were used: uncoated and coated stainless steels with composite polyether urethane/fullerene varnish. The experimental work was based on the study of the dependence of the permeation reduction factor on the temperature in the reactor. For the coated sample, the minimum temperature was 623 K at which the deuterium flux was registered. Here we assume that at temperatures below 573 K the output pressure caused by the deuterium flow through the sample is less than 10?10 Pa. The rate of steady-state flow through a coated sample is significantly lower than for an uncoated one at temperatures 573–673 K. The deuterium penetration rates through the two samples increase and reach similar stationary values starting at 723 K. 相似文献
67.
Carsten Pfüller Oliver Brandt Timur Flissikowski Caroline Chèze Lutz Geelhaar Holger T. Grahn Henning Riechert 《Nano Research》2010,3(12):881-888
Single, free-standing GaN nanowires grown by plasma-assisted molecular-beam epitaxy have been investigated with low temperature
micro-photoluminescence. The quantitative analysis of the luminescence spectra of around 100 nanowires revealed that each
nanowire exhibits its own individual spectrum. A significant fraction of nanowires exclusively emits at energies corresponding
to either surface-donor-bound or free excitons, demonstrating that optical properties of individual nanowires are determined
by a few impurity atoms alone. The number of impurities per nanowire and their location within the nanowires varies according
to Poissonian statistics. 相似文献
68.
Prof. Dr. Timur Dogu Prof. Dr. H. Onder Ozbelge Guest Editors 《Chemical Engineering Communications》2013,200(1-2):1-2
The T method is a newly developed one in distillation calculations which belongs to the class of methods which apply a partitioning of the whole system of equations to be solved It is similar in nature to the well known B.P. method or theta method, even if, when compared with them, it shows a higher efficiency in reaching the solution Following the basic ideas of the theta method, the T convergence promoter gives a better estimate of the liquid and vapor molar fractions profiles As a matter of fact, a better estimate of the temperature profiles, and physical properties is obtained. This situation allows the method to approach the solution by means of quicker convergence Some explanatory examples will be shown in order to demonstrate the feasibility of the proposed method. 相似文献
69.
Caglar Ozdemir Ozlet Akca E. Ilker Medine Dilek Odaci Demirkol Perihan Unak Suna Timur 《Food Analytical Methods》2012,5(4):731-736
Fe3O4 magnetic nanoparticles (MNPs) were synthesized and silanized to form a core–shell (Fe3O4–SiO2) structure. Afterwards, surface modification with amino silane was carried out to produce amino groups on the MNPs for the
biomolecule immobilization. In order to test the performance of amino functional MNPs as immobilization platform in biosensing
applications, glucose oxidase was immobilized on the surface via glutaraldehyde. Obtained Bio-MNPs were then fixed onto the
carbon paste electrode by the aid of magnetic force and used as the working electrode during the amperometric measurements
at −0.7 V versus Ag/AgCl. After optimization of some parameters affecting the biosensor performance, analytical characterization
was carried out. Linearity was found in the range of 0.25–2.0 mM glucose and defined by the equation of y = 8.366x + 1.819, (R
2 = 0.996). Proposed biosensor was then applied for the glucose analysis in various beverages. Finally, data were compared
with a commercial enzyme assay kit based on spectrophotometric Trinder reaction as a reference method. 相似文献
70.
Nanosized particles with different Ho3+ concentrations were synthesized in LaAlO3 lattices using a simple Pechini-type sol-gel method. X-ray diffraction measurements were used to investigate the structural composition and the effects of holmium dopant concentration on LaAlO3:Ho3+ crystal formation. Field-emission scanning-electron microscopy images confirm the formation of approximately spherical particles with an average size about 100 nm. The photoluminescence results yielded optimal holmium ion concentration in LaAlO3 host matrices was about 3% in mol equivalent. The mechanism that are responsible for the photoluminescence emission processes discussed with the help of Ho3+-ion Dieke energy level diagram. Power dependent slope measurements were performed to identify up-conversion photoluminescence process involved in LaAlO3:Ho3+. 相似文献