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61.
A vast number of publications have investigated the application of electrocoagulation (EC) process in heavy metal ions removal from wastewaters. Most of these studies were simple lab-scale using synthetic wastewater with the absence of holistic and systematic approach to consider the process complexity. This comprehensive review considers the fundamental aspects of EC processes such as mechanisms, kinetic models, and isotherm models used by different researchers. Furthermore, the impact of the main design and process operational parameters on the removal efficiency is discussed and analyzed. Many concluding remarks and perspectives are stated to give insights for possible future investigations. 相似文献
62.
László Gyarmati András Gulyás Balázs Sonkoly Tuan A. Trinh Gergely Biczók 《Computer Networks》2013,57(8):1758-1773
The increasing popularity of both small and large private clouds and expanding public clouds poses new requirements to data center (DC) architectures. First, DC architectures should be incrementally scalable allowing the creation of DCs of arbitrary size with consistent performance characteristics. Second, initial DC deployments should be incrementally expandable supporting small-scale upgrades without decreasing operation efficiency. A DC architecture possessing both properties satisfies the requirement of free-scaling.Recent work in DC design focuses on traditional performance and scalability characteristics, therefore resulting in symmetric topologies whose upgradability is coarse-grained at best. In our earlier work we proposed Scafida, an asymmetric, scale-free network inspired DC topology which scales incrementally and has favorable structural characteristics. In this paper, we build on Scafida and propose a full-fledged DC architecture achieving free-scaling called FScafida. Our main contribution is threefold. First, we propose an organic expansion algorithm for FScafida; this combined with Scafida’s flexible original design results in a freely scalable architecture. Second, we introduce the Effective Source Routing mechanism that provides near-shortest paths, multi-path and multicast capability, and low signaling overhead by exploiting the benefits of the FScafida topology. Third, we show based on extensive simulations and a prototype implementation that FScafida is capable of handling the traffic patterns characteristic of both enterprise and cloud data centers, tolerates network equipment failures to a high degree, and allows for high bisection bandwidth. 相似文献
63.
64.
Yeh-Wu Lao Shu-Ting Kuo Wei-Hsing Tuan 《Journal of Materials Science: Materials in Electronics》2009,20(3):234-241
The effects of powder bed on the microstructure and electrical properties of Bi2O3- and Sb2O3-doped ZnO specimens are investigated in the present study. By using a sufficient amount of powder bed, the weight loss of
Bi2O3 reduces from >95 to <20%. The reduction of weight loss enhances significantly the densification and grain growth of ZnO.
Furthermore, the use of powder bed can also reduce the size distribution of ZnO grains. Nevertheless, the presence of Bi2O3 residue results in the formation of a pyrochlore phase (Zn2Bi3Sb3O14) during the cooling down stage; its presence is detrimental to the nonlinear characteristics of ZnO–Bi2O3–Sb2O3 system. 相似文献
65.
Tuan Duong Nguyen Noriyuki Takahashi Isao Yamada 《Multidimensional Systems and Signal Processing》2013,24(3):457-483
The contribution of this paper is three-fold: first, we propose a novel scheme for generalized minor subspace extraction by extending an idea of dimension reduction technique. The key of this scheme is the reduction of the problem for extracting the ith (i ≥ 2) minor generalized eigenvector of the original matrix pencil to that for extracting the first minor generalized eigenvector of a matrix pencil of lower dimensionality. The proposed scheme can employ any algorithm capable of estimating the first minor generalized eigenvector. Second, we propose a pair of such iterative algorithms and analyze their convergence properties in the general case where the generalized eigenvalues are not necessarily distinct. Third, by using these algorithms inductively, we present adaptive implementations of the proposed scheme for estimating an orthonormal basis of the generalized minor subspace. Numerical examples show that the proposed adaptive subspace extraction algorithms have better numerical stability than conventional algorithms. 相似文献
66.
Phan Huy Hoang Anh Tuan Hoang Nguyen Hoang Chung Le Quang Dien Xuan Phuong Nguyen Xuan Duong Pham 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2018,40(3):312-319
In this study, new and efficient sorbent with density 0.2 g/cm3 was fabricated by incorporating rice straw into polyurethane matrix to get an open cell structure material with high oil uptake capacity. The influences of various important factors such as amount of adding rice straw, size of rice straw particles, and adsorption time on oil adsorption capacity of new sorbent material were investigated. The results showed that the oil absorption rate occurred fast in first 15–30 min, then slowed down and reached saturation level after about 2 h of treatment. Oil adsorption capacity of the new sorbent material was relatively high, up to 12.0 g/g. In comparison with pristine polyurethane or lignocellulosic materials, the new sorbents had higher oil adsorption capacity. Some characteristics of the as-obtained sorbent, such as surface shapes and porosity, were also studied by SEM analysis. 相似文献
67.
Nor Azah Yusof Nor Dyana Zakaria Nor Amirah Mohd Maamor Abdul Halim Abdullah Md. Jelas Haron 《International journal of molecular sciences》2013,14(2):3993-4004
Molecularly imprinted polymers (MIPs) were prepared by bulk polymerization in acetonitrile using 2,4-dinitrophenol, acrylamide, ethylene glycol dimethacrylate, and benzoyl peroxide, as the template, functional monomer, cross-linker, and initiator, respectively. The MIP membrane was prepared by hybridization of MIP particles with cellulose acetate (CA) and polystyrene (PS) after being ground and sieved. The prepared MIP membrane was characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. The parameters studied for the removal of 2,4-dinitrophenol included the effect of pH, sorption kinetics, and the selectivity of the MIP membrane. Maximum sorption of 2,4-nitrophenol by the fabricated CA membrane with MIP (CA-MIP) and the PS membrane with MIP (PS-MIP) was observed at pH 7.0 and pH 5.0, respectively. The sorption of 2,4-dinitrophenol by CA-MIP and PS-MIP followed a pseudo–second-order kinetic model. For a selectivity study, 2,4-dichlorophenol, 3-chlorophenol, and phenol were selected as potential interferences. The sorption capability of CA-MIP and PS-MIP towards 2,4-dinitrophenol was observed to be higher than that of 2,4-dichlorophenol, 3-chlorophenol, or phenol. 相似文献
68.
Hsiu-Ching Hsu Wei-Hsing Tuan Hsin-Yi Lee 《Materials science & engineering. C, Materials for biological applications》2009,29(3):950-954
In the present study, the in-situ transformation of calcium phosphate cement into hydroxyapatite (HAp) within the first hour is monitored with a synchrotron X-ray beam. A disodium hydrogen phosphate solution is used as cement liquid to activate the reaction between dicalcium phosphate anhydrous (DCPA) and calcium hydroxide (Ca(OH)2). The XRD analysis indicates that the amounts of DCPA and Ca(OH)2 first decrease within the first min of the reaction. Then, the intensity of DCPA's XRD peaks starts to increase instead in the period of 5 to 20 min. After 20 min, the DCPA particles are consumed slowly to form fine HAp particles. Large pores are evident upon the completion of reaction. 相似文献
69.
From Biomimetic Concept to Engineering Reality – A Case Study on the Design of Ceramic Reinforcement
The applications of ceramics are limited by their brittleness. Though the toughness of ceramics can be improved by adding hard and strong toughening agents, their damage tolerance is still poor. Novel concept derives from fish scale is explored and used to design alternative toughening agent. The microstructure of fish scale exhibits hierarchical complexity and many weak layers are present. As fish scales are used directly as the toughening agent, the toughness of ceramics can be enhanced. Furthermore, a new toughening mechanism involving crack deflection within fish scale is observed. Based on such observation, the toughening agents with internal weak interfaces are recommended as the toughening agent. Many ceramic/metal interfaces are present within the multilayer ceramic capacitors (MLCCs). The addition of MLCCs into brittle glass improves its crack resistance considerably. 相似文献
70.
The electrokinetic chromatographic separation of a series of inorganic and organic anions was achieved by utilizing an electrolyte system comprising a cationic soluble polymer (poly(diallydimethylammonium chloride, PDDAC) and a neutral beta-cyclodextrin (beta-CD) as pseudostationary phases. The separation mechanism was a combination of electrophoresis, ion-exchange (IE) interactions with PDDAC, and hydrophobic interactions with beta-CD. The extent of each chromatographic interaction was independently variable, allowing for control of the separation selectivity of the system. IE interactions could be varied by changing either the PDDAC concentration or the concentration of a competing ion (e.g., chloride) in the BGE, while the hydrophobic interactions could be varied by changing the concentration of beta-CD. The separation system was very robust, with the reproducibility of the migration times being <0.7% RSD. A mathematical model that predicted the mobilities of analytes under varying experimental conditions was derived and was shown to give good correlation (r2 = 0.9804) between predicted and experimental migration times. Parameters derived from the model were in good agreement with the ion-exchange and hydrophobic characteristics of the analytes. The model was also applied successfully to the optimization of conditions for the separation of a mixture of analytes or for conditions under which particular analytes migrated in a desired order. That is, the opportunity to tune the separation selectivity has been demonstrated. 相似文献