Papers by Keyword: Substitution

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Authors: Peng Fei Wang, Dian Hua Zhang, Xu Li, Wen Xue Zhang
Abstract: The work roll bending is one of the most effective flatness actuators in flatness control of cold rolled strips, as a result of its characteristics such as high speed response, powerful effects on the elimination of flatness defects such as edge-waves, central waves and so on. The existing research on flatness control mainly focuses on the calculation of optimal adjustment of individual flatness actuator. However, the final output of a flatness actuator is required to be limited firstly for some special cases. If the incoming strip is coming with big symmetrical flatness defects, it happens that the position limit of work roll bending is prone to be reached or exceeded during the execution of the displacement, resulting in the residual symmetrical flatness defects without further elimination, as well as a limited flatness control process. In order to avoid this situation, substitution control by intermediate roll bending in case of work roll bending control over-limitation have been developed, which is based on actuator efficiencies and in accordance with the practical conditions. Applications show that the substitution control of intermediate roll bending for work roll bending over-limitation can play an important role in the residually symmetrical flatness control.
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Authors: W. Dungkaew, K.J. Haller, A.E. Flood, J.F. Scamehorn
Abstract: The removal of arsenic from synthetic arsenic contaminated water sample by precipitating arsenic (in the form of arsenate oxyanion) with calcium phosphate hydroxyapatite, HAp, was studied under conditions that induce arsenate incorporated calcium phosphate hydroxyapatite, Ca (P/As)HAp, to form. Arsenate is able to substitute for a fraction of the phosphate in HAp host material as it forms. Consequently, arsenic is successfully removed from the contaminated water achieving up to 99% arsenic removal from 25 ppm initial arsenic concentration. The Ca:(P+As) and P:As mole ratios were found to play an important role in arsenic removal efficiency. Higher Ca:(P+As) and P:As mole ratios give higher arsenic removal efficiency. Surprisingly, the pH of the initial anion solution, a key parameter in arsenic speciation, was found to not have a significant effect on arsenic removal by this process. The advantage of this process is that the precipitation can occur rapidly at relatively low levels of arsenic contamination, implying an easy and inexpensive process for arsenic removal can be developed based on this approach.
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Authors: Wei Li, Min Yu Zhang, Dao Bin Mu, Tao Yang, Feng Wu
Abstract: In this paper, the characteristics of melted and annealed Co-free AB3-type hydrogen storage alloys in low-temperature condition were investigated by electrochemical tests. A series of Co-free AB3-type hydrogen storage alloys were synthesized with vacuum melting method, and be annealed by low-temperature heat treatment. The structures of alloys are simply discussed through SEM and XRD results. And discharge ability and cycle ability of alloys were tested. Experiment results indicate that characteristics of different AB3-type hydrogen storage alloys are affected by low-temperature obviously, and heated treatment could increase the discharge capacity of hydrogen storage alloy effectively, and improve the charge-discharge stability of alloy. Furthermore, non-metal element substituted alloy shows better Low-temperature applicability due to its weak crystallization. The discharge capacity of La0.7Mg0.3Ni2.9B0.05 alloy remains 91.2% after 30 cycles at 273K. And discharge capacity of heated La0.7Mg0.3Ni2.9(FeB)0.1 alloy could reach to 250mA·g-1.
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Authors: Qun Jiao Wang, Min Xu, Yi Bin Zhang
Abstract: (Ca1-xAx)3Co4O9 (A: Sr, Ba) composition-spread films were fabricated successfully on TiO2 (100) substrate by combinatorial pulsed laser deposition (CPLD), and their thermoelectric (TE) properties and structure were evaluated by the multi-channel thermoelectric measurement system and concurrent X-ray analysis respectively. The largest power factor in (Ca1-xSrx)3Co4O9 film library was achieved as 1.67µW/cmK2. The influence of substitution on TE properties was investigated by doping Sr2+ and Ba2+ ions into Ca3Co4O9. However, there was little change of Seebeck coefficient in the range of 0≤x≤0.1 for (Ca1-xAx)3Co4O9 (A: Sr, Ba) films, which suggested that the substitution ions with smaller size were potential candidates for good TE properties.
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Authors: Ilham Aguida Bella, Aîssa Asroun, Nabil Bella
Abstract: The aggregates factory consumes a big quantity of energy; by consequence, it costs money, in the other hand it produces a lot of waste material or SCM (sustainable concrete material). The main aspects which guide this study is the current tendency to make mortar based on a very abundant material which are crushed limestone aggregates and naturals dunes sand. The results obtained in this study summarize up the importance of SCMs aggregates on behavior of the mortar, this different kind of SCM aggregate offered different behavior at the fresh state of the batch and by consequence its result with different mechanical behavior at the hardened state of mortar. This study focus also on the behavior of the new kind of chemical admixture, which is acrylic superplasticizer. The principal aim of adding rolled or crushed SCM is makes a mortar, which can resist to exhaustive environment (at curing temperature).
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Authors: Yan Hong Gu, Wan Ping Chen, Ming Jian Ding, Jian Quan Qi
Abstract: BiFeO3, BiFe0.9Ti0.1O3 and BiFe0.9Ti0.05O3 ceramics were prepared by solid state reactions and were compared in electrical and dielectric properties. The resistivity of BiFe0.9Ti0.05O3 was 1.3×1012 Ω cm, which was about two and a half orders of magnitude higher than that of BiFeO3. and three times higher than that of BiFe0.9Ti0.1O3. The dielectric loss of BiFe0.9Ti0.05O3 was 0.1 and 0.02 at 100Hz and 1MHz, respectively. These phenomena can be explained base on the decrease of oxygen vacancies VO•• and defect complexes between the ferrum vacancies VFe and oxygen vacancies VO•• in the ceramics.
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Authors: Tie Jun Zhang, Ahmed A. Abd El-Latif, Mohamed Amin, Alaa Zaghloul
Abstract: In this paper, a new color image encryption mechanism based on multiple chaotic systems is proposed. In the proposal, two modules are achieved by mixing the features of horizontally and vertically adjacent pixels with the help of adopted multiple chaotic systems, respectively. Then, substitution/confusion is accomplished by generating an intermediate chaotic key stream image based on the adopted chaotic maps. Experimental results show that the proposed scheme is able to manage the trade-offs between the speed performance and security requirements.
327
Authors: Feng Yang, Dong Liang Zhao
Abstract: The change of the electronic structure in NiAl is investigated through DVM-the first principle method when Al in NiAl is substituted by Sc,Ti,V, Cr, Mn, Fe, Co, Ni, Cu, Zn. The results including Mulliken population, the charge distribution and cohesion energies are presented. The calculation of the electronic structure indicates that the substitution atoms take effect on the electronic structure of Ni and Al atoms surrounding the substitution atoms, and the ductility of NiAl. Among the substitution atoms that we studied, Fe, Co and Ni with more d electrons may be good for the ductility of NiAl.
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Authors: Min Yu Zhang, Feng Wu, Dao Bin Mu, Guo Qing Cao
Abstract: In this paper, First-principles calculation were used to investigate the effect of Fe substituted Co-free AB3-type hydrogen storage alloys. (La3Mg6Ni27)1/3 alloy (Hex structure) and (La3Mg6Ni26Fe1)1/3 alloy's crystal structures were build by Material studio software, Bond structure and DOS results were calculated. To compare with the calculated results, (La3Mg6Ni27)1/3 alloy and (La3Mg6Ni26Fe1)1/3 alloy were synthesized by vacuum melting method. The effect of Fe on such alloys are discussed according to calculate results and experiment results, as a first-principle investigation.
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Authors: Yu Hua Feng, Tie Zheng Pan, Xiang Qian Shen, Hao Jie Song, Li Ping Guo
Abstract: Piezoelectric ceramics with appropriate curie temperatures and high dielectric and piezoelectric performances are attractive for formations of ceramic/polymer piezoelectric composites. The PSZT ceramics with compositions of 0.98Pb1.0-xBaxTi0.48Zr0.52O3-0.02PbSbO3 (x=0.14~0.24) have been prepared by a conventional solid reaction process. The ceramic structures are analyzed by X-ray diffraction and the barium substitution leads to structural changes of the tetragonal and rhombohedral phases which constitute the perovskite PSZT ceramics, and lattice distortions. The curie temperature almost linearly decreases from 226 °C to 141 °C corresponding the barium content increases from 0.14 to 0.24 in the ceramics. The dielectric and piezoelectric properties are largely influenced by the barium substitution and when the barium content at vicinity of 0.22, the piezoelectric strain constant d33 exhibits a dramatic change. It is found that as the barium content around 0.22, the PSZT ceramic specimen is characterized with a low curie temperature Tc=156 °C, and satisfied dielectric and piezoelectric properties with the relative dielectric constant εr=5873, dielectric loss factor tanδ=0.0387, piezoelectric strain constant d33=578 pC/N.
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