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971.
Kannan M. Moudgalya Shivesh Kumar Singh Gaurav Jain 《Chemical engineering science》2003,58(17):3973-3983
An air-water experimental system consisting of two inlets and one outlet is constructed and characterised. It reaches the state of sliding mode, or equivalently, two phase slug flow. The linear hydraulic model proposed in the literature is adequate to describe it. Experimental data are used to tune this model. The resistance to the flow of air through the outlet valve during the two phase flow is much larger than that when air alone flows out. At the operating range, the resistance to water flow is not affected by the presence of air. 相似文献
972.
Castor oil (CO) based polyurethane (PU)– polyester nonwoven fabric composites were fabricated by impregnating the polyester nonwoven fabric in a reactive composition containing CO and diisocyanate. Composites were fabricated with two different isocyanates such as toluene‐2, 4‐diisocyanate (TDI) and hexamethylene diisocyanate (HMDI). Thermogravimetric analysis (TGA) studies of the composites were performed to establish the thermal stability and their mode of thermal degradation. It was found that degradation of neat PU takes place in two steps and that of polyester nonwoven fabric reinforced PU composites takes place in three steps. From the TGA thermograms, a little improvement in thermal stability incase of polyester nonwoven fabric reinforced PU composites were noticed compared to unreinforced PUs. Degradation kinetic parameters were obtained for the composites using Broido, Coats and Redfern, and Horowitz and Metzger methods. Tensile fractured composite specimens were used to analyze the morphology of the composites by scanning electron microscopic technique. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 相似文献
973.
Jae-Wook Lee Kyung-June Hwang Wang-Geun Shim Kyung-Hee Park Hal-Bon Gu Kyu-Hyuk Kwun 《Korean Journal of Chemical Engineering》2007,24(5):847-850
Dye sensitized solar cells (DSSCs) have been receiving significant attention because they have many advantages compared to
conventional organic solar cells. It has been known that the photovoltaic characteristics of DSSC are highly dependent on
the adsorption properties of dyes on TiO2 films. To analyze the surface heterogeneity of TiO2 surfaces, single-phase anatase nanocrystallite titanium films were prepared by sol-gel method using the hydrolysis reaction
of titanium tetraisopropoxide under acidic condition and characterized by XRD, FE-SEM and BET analysis. The adsorption energy
distribution functions were calculated by the generalized nonlinear regularization method. It was found that the shape and
the intensity of the adsorption energy distribution curve determined were highly related with the physical properties (i.e.,
geometrical heterogeneity) and chemical characteristics (i.e., energetic heterogeneity) of nanocrystalline TiO2 for DSSC. 相似文献
974.
P. V. S. S. Prabhu T. Prem Kumar P. N. N. Namboodiri R. Gangadharan 《Journal of Applied Electrochemistry》1993,23(2):151-156
Specific conductivities and viscosities of lithium perchlorate at four different concentrations (0.5, 1.0, 1.5 and 2.0 M) in ethylene carbonate (EC) based binary mixed solvent systems at 25°C are reported. The co-solvents chosen were tetrahydrofuran (THF), 1,2-dimethoxyethane (DME) and 1,3-dioxolane (DOL). Viscosity variations in all the three mixed solvent systems without electrolyte showed negative deviation from ideal behaviour thereby indicating the occurrence of a structure breaking effect in these three different binary systems. The increase in viscosity with increase in concentration of LiClO4 is attributed to the structural enhancement through the formation of a solvated complex which occupies interstitials in the solvent mixtures. 1 M LiClO4 solution shows maximum specific conductivity at 30 vol % EC for EC + DME and EC + DOL mixtures and at 50 vol % EC for EC + THF mixtures. Conductivity variations are explained on the basis of preferential solvation of lithium perchlorate by co-solvents (THF, DME and DOL) in their respective mixtures with ethylene carbonate. 相似文献
975.
976.
Hyun Min Shim Joon Soo Lee Hong Yue Wang Seung Hak Choi Jeong Hoon Kim Hyung Taek Kim 《Korean Journal of Chemical Engineering》2007,24(3):537-541
The main purpose of the study was to develop a model using ASPEN and Excel simulation method to establish optimum CO2 separation process utilizing hollow fiber membrane modules to treat exhaust gas from LNG combustion. During the simulation,
optimum conditions of each CO2 separation scenario were determined while operating parameters of CO2 separation process were varied. The characteristics of hollow fibers membrane were assigned as 60 GPU of permeability and
25 of selectivity for the simulation. The simulation results illustrated that 4 stage connection of membrane module is required
in order to achieve over 99% of CO2 purity and 90% of recovery rate. The resulted optimum design and operation parameters throughout the simulation were also
correlated with the experimental data from the actual CO2 separation facility which has a capacity of 1,000 Nm3/day located in the Korea Research Institute of Chemical Technology. Throughout the simulation, the operating parameters of
minimum energy consumption were evaluated. Economic analysis of pilot scale of CO2 separation plant was done with the comparison of energy cost of CO2 recovery and equipment cost of the plant based on the simulation model.
This work was presented at the 6
th
Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006. 相似文献
977.
T.V. Choudhary C. Sivadinarayana A.K. Datye D. Kumar D.W. Goodman 《Catalysis Letters》2003,86(1-3):1-8
Hydrogenation of acetylene has been investigated on Au/TiO2, Pd/TiO2 and Au-Pd/TiO2 catalysts at high acetylene conversion levels. The Au/TiO2 catalyst (avg. particle size: 4.6 nm) synthesized by the temperature-programmed reduction-oxidation of an Au-phosphine complex on TiO2 showed a remarkably high selectivity to ethylene formation even at 100% acetylene conversion. Au/TiO2 prepared by the conventional incipient wet impregnation method (avg. particle size: 30 nm), on the other hand, showed negligible activity for acetylene hydrogenation. Although the Au catalysts showed a high selectivity for ethylene, the acetylene conversion activity and catalyst stability were inferior to the Pd-based catalysts. Au-Pd catalysts prepared by the redox method showed high acetylene conversions as well as high selectivity for ethylene. Interestingly Au-Pd catalysts prepared by depositing Pd via the incipient wetness method on Au/TiO2 showed very poor selectivity (comparable to mono-metallic Pd catalysts) for ethylene. High-resolution transmission electron microscopy (TEM) studies coupled with energy dispersive X-ray spectroscopy (EDS) showed that while the redox method produced bimetallic Au-Pd catalysts, the latter method produced individual Pd and Au particles on the support. 相似文献
978.
Jim D. Earls Jerry E. White Marvin L. Dettloff Marty J. Null 《Journal of Coatings Technology and Research》2004,1(3):243-245
Epoxidized 10-undecenoic acid triglyceride, an experimental seed oil derivative that has a terminal epoxy group on each of
the three acyl glyceride segments, has been found to have good reactivity with amine curatives and allows room temperature
cures to be obtained. Coatings based on epoxidized 10-undercenoic acid triglyceride have also shown excellent UV stability.
As an example, coatings samples placed in a QUVA chamber exhibit no loss in gloss after 3000 hr of a cycled exposure to high
intensity UV lamps and moisture at temperatures of 50–60°C. In comparison, coatings based on standard liquid epoxy resins
(LERs) and commercially available hydrogenated LERs lose gloss due to chalking/decomposition within 200–800 hr.
Presented at the 81 st Annual Meeting of the Federation of Societies for Coatings Technology, November 12–14, 2003, in Philadelphia,
PA. 相似文献
979.
The pulsed arc discharge to the surface of wastewater was applied to the degradation of a textile azo dye (Acid Red 27). A
high-voltage electrode (discharging electrode) was vertically placed above the surface of the wastewater while the wastewater
itself was grounded. The pulsed arc discharge occurred between the tip of the discharging electrode and the surface of the
wastewater, producing various oxidative species. Oxygen was used as the working gas instead of air to prevent nitrogen oxides
from forming. The effect of several parameters on the chromaticity and chemical oxygen demand (COD) removal was examined.
The results obtained showed that the chromaticity of the wastewater was completely removed by this process and the COD also
decreased significantly. It has been found that ozone formed in the gas phase mainly affects the removal of the dye. The contribution
of other effects such as ultraviolet light emission and OH radical formation during the arc discharge to the degradation of
the dye was found to be less than 15%. For the present reactor system, the optimum pH, pulse repetition rate and agitation
speed were found to be 3.0, 110 Hz and 300 rpm, respectively. 相似文献
980.
Crop residue,manure and fertilizer in dryland maize under reduced tillage in northern China: I grain yields and nutrient use efficiencies 总被引:4,自引:0,他引:4
Xiaobin Wang Dianxiong Cai Willem B. Hoogmoed Udo D. Perdok Oene Oenema 《Nutrient Cycling in Agroecosystems》2007,79(1):1-16
The rapidly increasing population and associated quest for food and feed in China has led to increased soil cultivation and
nitrogen (N) fertilizer use, and as a consequence to increased wind erosion and unbalanced crop nutrition. In the study presented
here, we explored the long-term effects of various combinations of maize stover, cattle manure and nitrogen (N) and phosphorus
(P) fertilizer applications on maize (Zea mays L.) yield and nutrient and water use efficiencies under reduced tillage practices. In a companion paper, we present the effects
on nutrient balances and soil fertility characteristics. The ongoing factorial field trial was conducted at Shouyang Dryland
Farming Experimental Station in northern China from 1993 onwards. The incomplete, determinant-optimal design comprised 12
treatments, including a control treatment, in duplicate. Grain yields and N, P, and potassium (K) uptakes and N, P and K use
efficiencies were greatly influenced by the amount of rain during the growing season (GSR), and by soil water at sowing (SWS).
There were highly significant interactions between GSR and added stover and manure, expressed in complex annual variations
in grain yield and N, P and K use efficiencies. Annual mean grain yields ranged from 3,000 kg ha−1 to 10,000 kg ha−1 and treatment mean yields from 4,500 kg ha−1 to 7,000 kg ha−1. Balanced combination of stover (3,000–6,000 kg), manure (1,500–6,000 kg) and N fertilizer (105 kg) gave the highest yield.
Stover and manure were important for supplying K, but the effects differed greatly between years. Overall mean N recovery
efficiency (NRE) ranged from 28% to 54%, depending on N source. NRE in wet years ranged from 50% to 90%. In conclusion, balanced
combinations of stover, manure and NP fertilizer gave the highest yield and NRE. Reduced tillage with adding stover and manure
in autumn prior to ploughing is effective in minimizing labor requirement and wind erosion. The potentials of split applications
of N fertilizer, targeted to the need of the growing crop (response farming), should be explored to further increase the N
use efficiency. 相似文献