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排序方式: 共有102条查询结果,搜索用时 171 毫秒
1.
In this present work, Ca-alginate-biochar adsorbent has been synthesized, characterized and tested its effectiveness in the removal of aqueous phase Zn2+ metal. The removal efficiency was studied under various physicochemical process parameters. External mass transfer model, intraparticle diffusion model and pseudo-first-order and pseudo-second-order models were used to fit the experimental Zn2+ adoption kinetic results and to identify the mechanism of adsorption. The desorption studies indicate the possibilities of ion-exchange and physical–chemical adsorption of Zn2+. The adsorption was best described by Langmuir isotherm model. Thermodynamic parameters suggested that the adsorption process becomes spontaneous, endothermic and irreversible in nature. 相似文献
2.
Amanda D’Cruz Mangesh G. Kulkarni Lekha Charan Meher Ajay K. Dalai 《Journal of the American Oil Chemists' Society》2007,84(10):937-943
A series of alkali metal (Li, Na, K) promoted alkali earth oxides (CaO, BaO, MgO), as well as K2CO3 supported on alumina (Al2O3), were prepared and used as catalysts for transesterification of canola oil with methanol. Four catalysts such as K2CO3/Al2O3 and alkali metal (Li, Na, K) promoted BaO were effective for transesterification with >85 wt% of methyl esters. ICP-MS analysis
revealed that leaching of barium in ester phase was too high (~1,000 ppm) when BaO based catalysts were used. As barium is
highly toxic, these catalysts were not used further for transesterification of canola oil. Optimization of reaction conditions
such as molar ratio of alcohol to oil (6:1–12:1), reaction temperature (40–60 °C) and catalyst loading (1–3 wt%) was performed
for most efficient and environmentally friendly K2CO3/Al2O3 catalyst to maximize ester yield using response surface methodology (RSM). The RSM suggested that a molar ratio of alcohol
to oil 11.48:1, a reaction temperature of 60 °C, and catalyst loading 3.16 wt% were optimum for the production of ester from
canola oil. The predicted value of ester yield was 96.3 wt% in 2 h, which was in agreement with the experimental results within
1.28%. 相似文献
3.
4.
F.A. Ansari V. Charan V.K. Varma 《International Communications in Heat and Mass Transfer》1984,11(6):583-590
An experimental apparatus was designed to verify the method of measurement of thermal diffusivity of food produce proposed by the authors in an earlier paper [1]. Also, measurements were done for the time-temperature variation during transient cooling of food produce, and the temperature variation has been calculated by many methods available in the literature. It has been found that the calculation procedure proposed by the authors earlier [2] yielded consistently improved results. 相似文献
5.
6.
On the constrained synthesis of array patterns with applications to circular and arc arrays 总被引:1,自引:0,他引:1
Synthesis of array patterns involving optimization with linear and nonlinear constraints is considered. The general solution for the composite weight vector can be decomposed into a part which satisfies the linear constraints and another lying orthogonal to it. This decomposition is shown to yield simple solutions to several beam optimization problems including some with nonlinear constraints. A geometrical derivation of this result is presented which also provides new insights into the mechanism of null-steering via linear constraints. Application of this approach in conjunction with some search algorithms to the synthesis of optimum array patterns with prescribed narrow or broad nulls is shown to yield interesting and useful solutions. The results are illustrated by considering the design of "circular" and "arc" arrays. 相似文献
7.
In this investigation, water side heat transfer coefficients without air flow from a single horizontal tubes are determined. Mass transfer coefficients are determined with water and air flow from the same tube. The total energy dissipated by inside hot fluid when only water is falling is compared with that when both the air and water flow past the tube. The water side heat transfer coefficient and mass transfer coefficient are given by empirical relations hw = 6.0(Rep)0.18(Rew)0.87 and K = 3.5(Rep)0.18(Rea)0.28 (Rew)0.54, respectively. The ratio of energies dissipated with water and air flow and with only water flow increases with Rew and Rea and its maximum value is 1.72 in the range of variables used. 相似文献
8.
NB Charan SR Johnson S Lakshminarayan WH Thompson P Carvalho 《Canadian Metallurgical Quarterly》1997,82(2):686-692
In anesthetized sheep, we measured bronchial blood flow (Qbr) by an ultrasonic flow probe to investigate the interaction between inhaled nitric oxide (NO; 100 parts/million) given for 5 min and 5 ml of aerosolized isoetharine (1.49 x 10(-2) M concentration). NO and isoetharine increased Qbr from 26.5 +/- 6.5 to 39.1 (SE) +/- 10.6 and 39.7 +/- 10.7 ml/min, respectively (n = 5). Administration of NO immediately after isoetharine further increased Qbr to 57.3 +/- 15.1 ml/min. NO synthase inhibitor N(omega)-nitro-L-arginine methyl ester hydrochloride (L-NAME; 30 mg/kg, in 20 ml saline given i.v.) decreased Qbr to 14.6 +/- 2.6 ml/min. NO given three times alternately with isoetharine progressively increased Qbr from 14.6 +/- 2.6 to 74.3 +/- 17.0 ml/min, suggesting that NO and isoetharine potentiate vasodilator effects of each other. In three other sheep, after L-NAME three sequential doses of isoetharine increased Qbr from 10.2 +/- 3.4 to 11.5 +/- 5.7, 11.7 +/- 4.7, and 13.3 +/- 5.7 ml/min, respectively, indicating that effects of isoetharine are predominantly mediated through synthesis of NO. When this was followed by three sequential administrations of NO, Qbr increased by 146, 172, and 185%, respectively. Thus in the bronchial circulation, there seems to be a close interaction between adenosine 3',5'-cyclic monophosphate- and guanosine 3',5'-cyclic monophosphate-mediated vasodilation. 相似文献
9.
Mishra Devi Prasad Panigrahi Durga Charan Kumar Pradeep Kumar Abhijeet Sinha Pritam Kumar 《Neural computing & applications》2021,33(1):181-190
Neural Computing and Applications - Dispersing methane to a safer level is crucial for mines safety as methane has been the greatest contributor of explosion hazard in underground coal mines... 相似文献
10.
An ultra‐wideband planar fractal monopole antenna with dual‐notch characteristics is presented in this article. The microstrip fed antenna consists of nested trapezoidal rings and defected ground plane. Measured results show that the proposed antenna operates with a 10 dB return loss bandwidth from 2.2 to 10.8 GHz with notch bands at (2500‐2690) MHz and (3300‐4200) MHz covering LTE 2500, WiMAX and part of C‐band. 相似文献