Search results for: copper oxide cluster

Authors: Israa Al-Neami, Ali J. Al-Askery, Martin Johnston, Charalampos Tsimenidis

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In this paper, we focus on the design of a multi-line copper wire (MLCW) communication system. First, we construct our proposed MLCW channel and verify its characteristics based on the Kolmogorov-Smirnov test. In addition, we apply Middleton class A impulsive noise (IN) to the copper channel for further investigation. Second, the MIMO G.fast system is adopted utilizing the proposed MLCW channel model and is compared to a single line G-fast system. Second, the performance of the coded system is obtained utilizing concatenated interleaved Reed-Solomon (RS) code with four-dimensional trellis-coded modulation (4D TCM), and compared to the single line G-fast system. Simulations are obtained for high quadrature amplitude modulation (QAM) constellations that are commonly used with G-fast communications, the results demonstrate that the bit error rate (BER) performance of the coded MLCW system shows an improvement compared to the single line G-fast systems.

Keywords: G.fast, Middleton Class A impulsive noise, mitigation techniques, Copper channel model

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Authors: Krasimir Ivanov, Elitsa Kolentsova, Dimitar Dimitrov

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The development of active and stable catalysts without noble metals for low temperature oxidation of exhaust gases remains a significant challenge. The purpose of this study is to determine the influence of the preparation method on the catalytic activity of the supported copper-manganese mixed oxides in terms of VOCs oxidation. The catalysts were prepared by impregnation of γ-Al2O3 with copper and manganese nitrates and acetates and the possibilities for CO, CH3OH and dimethyl ether (DME) oxidation were evaluated using continuous flow equipment with a four-channel isothermal stainless steel reactor. Effect of the support, Cu/Mn mole ratio, heat treatment of the precursor and active component loading were investigated. Highly active alumina supported Cu-Mn catalysts for CO and VOCs oxidation were synthesized. The effect of preparation conditions on the activity behavior of the catalysts was discussed. The synergetic interaction between copper and manganese species increases the activity for complete oxidation over mixed catalysts. Type of support, calcination temperature and active component loading along with catalyst composition are important factors, determining catalytic activity. Cu/Mn molar ratio of 1:5, heat treatment at 450oC and 20 % active component loading are the best compromise for production of active catalyst for simultaneous combustion of CO, CH3OH and DME.

Keywords: copper-manganese catalysts, CO, VOCs oxidation, exhaust gases

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Authors: F. Berna Benli, Özgür Keskin

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Lately, many mathematicians have been studied the statistical convergence of a sequence of fuzzy numbers. We know that Lambda-statistically convergence is a kind of convergence between ordinary convergence and statistical convergence. In this paper, we will introduce the new kind of convergence such as λ-levelwise statistical convergence. Then, we will define the concept of the λ-levelwise statistical cluster and limit points of a sequence of fuzzy numbers. Also, we will discuss the relations between the sets of λ-levelwise statistical cluster points and λ-levelwise statistical limit points of sequences of fuzzy numbers. This work has been extended in this paper, where some relations have been considered such that when lambda-statistical limit inferior and lambda-statistical limit superior for lambda-statistically convergent sequences of fuzzy numbers are equal. Furthermore, lambda-statistical boundedness condition for different sequences of fuzzy numbers has been studied.

Keywords: fuzzy number, λ-levelwise statistical cluster points, λ-levelwise statistical convergence, λ-levelwise statistical limit points, λ-statistical cluster points, λ-statistical convergence, λ-statistical limit points

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Authors: Yu Wang, Xibang Chen, Maolin Zhai, Jing Peng, Jiuqiang Li

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Poly(acrylic acid) (PAA) functionalized magnetic graphene oxide (GO) composite was synthesized through a two-step process. Magnetic Fe₃O₄/GO was first prepared by a facile hydrothermal method. A radiation-induced grafting technique was used to graft PAA to Fe₃O₄/GO to obtain the Fe₃O₄/GO-g-PAA subsequently. The characteristics results of FTIR, Raman, XRD, SEM, TEM, and VSM showed that Fe₃O₄/GO-g-PAA was successfully prepared. The Fe₃O₄/GO-g-PAA composites were used as sorbents for the removal of Pb(II) ions, and the maximum adsorption capacity for Pb(II) was 176.92 mg/g.

Keywords: Fe₃O₄, graphene oxide, magnetic, Pb(II) removal, radiation-induced

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Authors: P. G. Siddheshwar, B. N. Veena

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Rayleigh-B´enard convection of a nanoliquid in shallow, square and tall enclosures is studied using the Khanafer-Vafai-Lightstone single-phase model. The thermophysical properties of water, copper, copper-oxide, alumina, silver and titania at 3000 K under stagnant conditions that are collected from literature are used in calculating thermophysical properties of water-based nanoliquids. Phenomenological laws and mixture theory are used for calculating thermophysical properties. Free-free, rigid-rigid and rigid-free boundary conditions are considered in the study. Intractable Lorenz model for each boundary combination is derived and then reduced to the tractable Ginzburg-Landau model. The amplitude thus obtained is used to quantify the heat transport in terms of Nusselt number. Addition of nanoparticles is shown not to alter the influence of the nature of boundaries on the onset of convection as well as on heat transport. Amongst the three enclosures considered, it is found that tall and shallow enclosures transport maximum and minimum energy respectively. Enhancement of heat transport due to nanoparticles in the three enclosures is found to be in the range 3% - 11%. Comparison of results in the case of rigid-rigid boundaries is made with those of an earlier work and good agreement is found. The study has limitations in the sense that thermophysical properties are calculated by using various quantities modelled for static condition.

Keywords: enclosures, free-free, rigid-rigid, rigid-free boundaries, Ginzburg-Landau model, Lorenz model

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Authors: Ude N. Callistus, Amulu F. Ndidi, Onukwuli D. Okechukwu, Amulu E. Patrick

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Power law approximation was used in this study to evaluate the reaction orders of calcium oxide, CaO catalyzed transesterification of refined cottonseed oil and methanol. The kinetics study was carried out at temperatures of 45, 55 and 65 ^oC. The kinetic parameters such as reaction order 2.02 and rate constant 2.8 hr^-1g^-1cat, obtained at the temperature of 65 ^oC best fitted the kinetic model. The activation energy, Ea obtained was 127.744 KJ/mol. The results indicate that the transesterification reaction of the refined cottonseed oil using calcium oxide catalyst is approximately second order reaction.

Keywords: refined cottonseed oil, transesterification, CaO, heterogeneous catalysts, kinetic model

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Authors: Bahattin Duzgun, Adem Kocyigit, Demet Tatar, Ahmet Battal

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Tin oxide thin films are semiconductor materials highly transparent and with high mechanical and chemical stability, except for their interactions with oxygen atoms at high temperature. Many dopants, such as antimony (Sb), arsenic (As), fluorine (F), indium (In), molybdenum and (Mo) etc. have been used to improve the electrical properties of tin oxide films. Among these, Sb and F are found to be the most commonly used dopants for solar cell layers. Also Tin oxide tin films investigated and characterized by researchers different film deposition and analysis method. In this study, tin oxide thin films are deposited on glass substrate by spin coating technique and characterized by FTIR and AFM. FTIR spectroscopy revealed that all films have O-Sn-O and Sn-OH vibration bonds not changing with layer effect. AFM analysis indicates that all films are homogeneity and uniform. It can be seen that all films have needle shape structure in their surfaces. Uniformity and homogeneity of the films generally increased for increasing layers. The results found in present study showed that doubly doped SnO2 thin films is a good candidate for solar cells and other optoelectronic and technological applications.

Keywords: doubly doped, spin coating, FTIR analysis, AFM analysis

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Authors: Jularat Chumnaul

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In forensic science, corpses from various homicides are different; there are both complete and incomplete, depending on causes of death or forms of homicide. For example, some corpses are cut into pieces, some are camouflaged by dumping into the river, some are buried, some are burned to destroy the evidence, and others. If the corpses are incomplete, it can lead to the difficulty of personally identifying because some tissues and bones are destroyed. To specify gender of the corpses from skeletal remains, the most precise method is DNA identification. However, this method is costly and takes longer so that other identification techniques are used instead. The first technique that is widely used is considering the features of bones. In general, an evidence from the corpses such as some pieces of bones, especially the skull and pelvis can be used to identify their gender. To use this technique, forensic scientists are required observation skills in order to classify the difference between male and female bones. Although this technique is uncomplicated, saving time and cost, and the forensic scientists can fairly accurately determine gender by using this technique (apparently an accuracy rate of 90% or more), the crucial disadvantage is there are only some positions of skeleton that can be used to specify gender such as supraorbital ridge, nuchal crest, temporal lobe, mandible, and chin. Therefore, the skeletal remains that will be used have to be complete. The other technique that is widely used for gender specifying in forensic science and archeology is skeletal measurements. The advantage of this method is it can be used in several positions in one piece of bones, and it can be used even if the bones are not complete. In this study, the classification and cluster analysis are applied to this technique, including the Kth Nearest Neighbor Classification, Classification Tree, Ward Linkage Cluster, K-mean Cluster, and Two Step Cluster. The data contains 507 particular individuals and 9 skeletal measurements (diameter measurements), and the performance of five methods are investigated by considering the apparent error rate (APER). The results from this study indicate that the Two Step Cluster and Kth Nearest Neighbor method seem to be suitable to specify gender from human skeletal remains because both yield small apparent error rate of 0.20% and 4.14%, respectively. On the other hand, the Classification Tree, Ward Linkage Cluster, and K-mean Cluster method are not appropriate since they yield large apparent error rate of 10.65%, 10.65%, and 16.37%, respectively. However, there are other ways to evaluate the performance of classification such as an estimate of the error rate using the holdout procedure or misclassification costs, and the difference methods can make the different conclusions.

Keywords: skeletal measurements, classification, cluster, apparent error rate

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Authors: Jarunee Wonglimpiyarat

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This paper explores the innovation management strategy of Thailand in moving towards the Detroit of Asia. The study analyses Thailand’s automotive cluster based on Porter’s Diamond Model and national innovation system (NIS) framework. A qualitative methodology was carried out, using semi-structured interviews with the players in the Thai automotive industry. Thailand took a different NIS approach by pursuing an Original Equipment Manufacture (OEM) strategy to attract foreign investments in building its automotive cluster, a different path from other Asian countries that competed with Own Brand Manufacture (OBM) strategies. The findings provide useful lessons for other newly industrialized countries (NICs) in adopting the cluster policies to move up the technological ladders.

Keywords: innovation management strategy, national innovation system (NIS), Detroit of Asia, original equipment manufacturer (OEM)

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Authors: Tzu-Wen Liu, Yi-Feng Lin, Yu-Shao Chen

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CO_2 is believed to be partly responsible for changes to the global climates. Carbon capture and storage (CCS) is one way to reduce carbon dioxide emissions in the past. Recently, how to convert the captured CO_2 into fine chemicals gets lots of attention owing to reducing carbon dioxide emissions and providing greener feedstock for the chemicals industry. A variety of products can be manufactured from carbon dioxide and the most attractive products are cyclic carbonates. Therefore, the kind of catalyst plays an important role in cycloaddition of carbon dioxide to epoxides. Magnesium oxide can be an efficiency heterogeneous catalyst for the cycloaddition of carbon dioxide to epoxides because magnesium oxide has both acid and base active sites and can provide the adsorption of carbon dioxide, promoting ring-opening reaction. Spinning disk reactor (SDR) is one of the device of high-gravity technique and has successfully used for synthesis of nanoparticles by precipitation methods because of the high mass transfer rate. Synthesis of nanoparticles in SDR has advantages of low energy consumption and easy to scale up. The aim of this research is to synthesize magnesium hydroxide nanoparticles in SDR as precursors for magnesium oxide. Experimental results showed that the calcination temperature of magnesium hydroxide to magnesium oxide, and the pressure and temperature of cycloaddition reaction had significantly effect on the conversion and selectivity of the reaction.

Keywords: magnesium oxide, catalyst, cycloaddition, spinning disk reactor, carbon dioxide

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Authors: Weili Shao, Qian Wang, Jianxin He

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Recently, the applications of graphene oxide in fabricating scaffolds for bone tissue engineering have been received extensive concern. In this work, poly l-lactic/graphene oxide composite nanofibers were successfully fabricated by electrospinning. The morphology structure, porosity and mechanical properties of the composite nanofibers were characterized using different techniques. And mouse mesenchymal stem cells were cultured on the composite nanofiber scaffolds to assess their suitability for bone tissue engineering. The results indicated that the composite nanofiber scaffolds had finer fiber diameter and higher porosity as compared with pure poly l-lactic nanofibers. Furthermore, incorporation of graphene oxide into the poly l-lactic nanofibers increased protein adsorptivity, boosted the Young’s modulus and tensile strength by nearly 4.2-fold and 3.5-fold, respectively, and significantly enhanced adhesion, proliferation, and osteogenesis in mouse mesenchymal stem cells. The results indicate that composite nanofibers could be excellent and versatile scaffolds for bone tissue engineering.

Keywords: poly l-lactic, graphene oxide, osteogenesis, bone tissue engineering

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Authors: Olusola Joseph Adesina, Abiodun Ezekiel Adesina

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Efforts at improving the falling standard of education in the country call for the need-based assessment of the primary tier of education in Nigeria. Teachers’ cluster meeting intervention is a step towards enhancing the teachers’ professional competency, efficient and effective pupils’ academic achievement and attitudinal development. The study thus determined the impact of the intervention on pupils’ achievement in Oyo State, Nigeria. Three research questions and four hypotheses guided the study. Pre-test, post-test control group, quasi-experimental design was adopted for the study. Eight intact classes from eight different schools were randomly selected into treatment and control groups. Two response instruments, pupils academic achievement test (PAAT; r = 0.87) and pupils attitude to lesson scale (PALS; r = 0.80) were used for data collection. Mean, standard deviation and analysis of covariance (ANCOVA) were used to analyse the collected data. The results showed that the teachers’ cluster meeting have significant impact on pupils academic achievement (F (1,327) =41.79; p<0.05) and attitudinal development (F (1,327) =26.01; p<0.05) in the core subjects of primary schools in Oyo State, Nigeria. The study therefore recommended among others that teachers’ cluster meeting should be sustained for teachers’ professional development and pupils’ upgradement in the State.

Keywords: teachers’ cluster meeting, pupils’ academic achievement, pupils’ attitudinal development, academic achievement

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Authors: C. Rajalakshmi, Vibin Ipe Thomas

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Sonogashira coupling reactions are widely employed in the synthesis of molecules of biological and pharmaceutical importance. Copper catalyzed Sonogashira coupling reactions are gaining importance owing to the low cost and less toxicity of copper as compared to the palladium catalyst. In the present work, a detailed computational study has been carried out on the Sonogashira coupling reaction between aryl halides and terminal alkynes catalyzed by Copper (I) species with trans-1, 2 Diaminocyclohexane as ligand. All calculations are performed at Density Functional Theory (DFT) level, using the hybrid Becke3LYP functional. Cu and I atoms are described using an effective core potential (LANL2DZ) for the inner electrons and its associated double-ζ basis set for the outer electrons. For all other atoms, 6-311G+* basis set is used. We have identified that the active catalyst species is a neutral 3-coordinate trans-1,2 diaminocyclohexane ligated Cu (I) alkyne complex and found that the oxidative addition and reductive elimination occurs in a single step proceeding through one transition state. This is owing to the ease of reductive elimination involving coupling of Csp2-Csp carbon atoms and the less stable Cu (III) intermediate. This shows the mechanism of copper catalyzed Sonogashira coupling reactions are quite different from those catalyzed by palladium. To gain further insights into the mechanism, substrates containing various functional groups are considered in our study to traverse their effect on the feasibility of the reaction. We have also explored the effect of ligand on the catalytic cycle of the coupling reaction. The theoretical results obtained are in good agreement with the experimental observation. This shows the relevance of a combined theoretical and experimental approach for rationally improving the cross-coupling reaction mechanisms.

Keywords: copper catalysed, density functional theory, reaction mechanism, Sonogashira coupling

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Authors: Ali Moafi, Kourosh Kalantarzadeh, Richard Kaner, Parviz Parvin, Ebrahim Asl Soleimani, Dougal McCulloch

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In-situ Raman spectroscopy of flexible graphene-oxide films examined upon exposure to hydrogen gas, air, and synthetic air. The changes in D and G peaks are attributed to defects responding to atomic hydrogen spilled over from the catalytic behavior of Pt nanoparticles distributed all over the film. High-resolution transmission electron microscopy images (HRTEM) as well as electron energy loss spectroscopy (EELS) were carried out to define the density of the samples.

Keywords: in situ Raman Spectroscopy, EELS, TEM, graphene oxide, graphene, atomic hydrogen

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Authors: Mahmoud Ashraf Farouk

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Shipping transportation is the foremost imperative mode of transportation in universal coordination. At display, more than 2/3 of the full worldwide exchange volume accounts for shipping transportation. Ships are utilized as an implies of marine transportation, introducing large-power diesel motors with exhaust containing nitrogen oxide NOx, sulfur oxide SOx, carbo di-oxide CO₂, particular matter PM10, hydrocarbon HC and carbon mono-oxide CO which are the most dangerous contaminants found in exhaust gas from ships. Ships radiating a large amount of exhaust gases have become a significant cause of pollution in the air in coastal areas, harbors and oceans. Therefore, IMO (the International Maritime Organization) has established rules to reduce this emission. This experiment shows the measurement of the exhaust gases emitted from the Aida IV ship's main engine using marine diesel oil fuel (MDO). The measurement is taken by the Sensonic2000 device on 85% load, which is the main sailing load. Moreover, the paper studies different emission reduction technologies as an alternative fuel, which as liquefied natural gas (LNG) applied to the system and reduction technology which is represented as selective catalytic reduction technology added to the marine diesel oil system (MDO+SCR). The experiment calculated the amount of nitrogen oxide NOx, sulfur oxide SOx, carbon-di-oxide CO₂, particular matter PM10, hydrocarbon HC and carbon mono-oxide CO because they have the most effect on the environment. The reduction technologies are applied on the same ship engine with the same load. Finally, the study found that MDO+SCR is the more efficient technology for the Aida IV ship as a training and supply ship due to low consumption and no need to modify the engine. Just add the SCR system to the exhaust line, which is easy and cheapest. Moreover, the differences between them in the emission are not so big.

Keywords: marine, emissions, reduction, shipping

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Authors: Katarína Koňariková, Georgios A. Perdikaris, Lucia Andrezálová, Zdeňka Ďuračková, Lucia Laubertová, Helena Gbelcová, Ingrid Žitňanová

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Introduction: The continuous demand for new anti-cancer drugs has stimulated chemotherapeutic research based on the use of essential metalloelements with the aim to develop potential drugs with lower toxicity and higher antiproliferative activity against tumors. Copper(II) and its complexes play an important role as suitable species for antiproliferative tests. Objectives: The central objective of the current study was to investigate the potential in vitro anti-proliferative effects of N-salicylidene-L-glutamato copper (II) complexes and molecular mechanism of apoptosis induced by tested complexes. In our project we tested N-salicylidene-L-glutamato copper (II) complexes ZK1 - [Cu(N-salicylidene-L-glutamato)(H2O)2].H2O; MK0 - ([Cu2(N-sal-D,L-glu)2(isoquinoline)2].2H2O); MK1 - [Cu(N-salicylidene-5-methyl-L-glutamato)(H2O)].H2O; MK3 - transbis(ethanol)tetrakis(imidazol)Cu(II)(2+)bis(N-salicylidene-D,L-glutamato-N,O)-KO:KO´-(imidazol); MK5 - [Cu(N-salicylidene-D,L- glutamato)(2-methylimidazol] at concentration range 0.001-100 µmol/L against human colon carcinoma cell line HT-29 and human breast carcinoma cell line MCF-7. Methods: Viability was assessed by direct counting of 0.4% trypan blue dye-excluding cells after 24, 48 and 72 hour cultivations with or without copper complex and by MTT assay. To analyze the type of cell death and its mechanism induced by our copper complex we used different methods. To distinguish apoptosis from necrosis we used electrophoretic analysis, to study the activity of caspases 8 and 9 – luminometric analysis and caspase activity 3 colorimetric assay. Results: The observed anti-proliferative effect of the copper complexes appeared to be dose-, time- and cell line- dependent. Human colon carcinoma cells HT-29 appeared to be more sensitive to the complex MK0 ([Cu2(N-sal-D,L-glu)2(isoquinoline)2].2H2O) than to ZK1 ([Cu(N-salicylidene-L-glutamato)(H2O)2].H2O) and MK1 ([Cu(N-salicylidene-5-methyl-L-glutamato)(H2O)].H2O)). Human colon carcinoma cells HT-29 appeared to be more sensitive to the complex than human breast carcinoma cells MCF-7. IC50 decreased with time of incubation (24, 48 and 72h) for HT-29, but increased for MCF-7. By electrophoresis we found apoptotic cell death induced by our copper complexes in HT-29 at concentrations 1, 10, 50 and 100 µmol/L after 48h (ZK1) and 72h (MK0, MK1) and in MCF-7 we did not find apoptosis. We also studied molecular mechanism of apoptosis in HT-29 induced by copper complexes. We found active caspase 9 in HT-29 after ZK1 ([Cu(N-salicylidene-L-glutamato)(H2O)2].H2O) and MK1 ([Cu(N-salicylidene-5-methyl-L-glutamato)(H2O)].H2O)) influence and active caspase 8 after MK0 ([Cu2(N-sal-D,L-glu)2(isoquinoline)2].2H2O) influence. Conclusion: Our copper complexes showed cytotoxic activities against human colon carcinoma cells HT-29 and breast cancer cell line MCF-7 in vitro. Apoptosis was activated by mitochondrial pathway (intrinsic pathway) in case of ZK1 [Cu(N-salicylidene-L-glutamato)(H2O)2].H2O; MK1 [Cu(N-salicylidene-5-methyl-L-glutamato)(H2O)].H2O; MK3 - transbis(ethanol)tetrakis(imidazol)Cu(II)(2+)bis(N-salicylidene-D,L-glutamato-N,O)-KO:KO´-(imidazol) and MK5 - [Cu(N-salicylidene-D,L- glutamato)(2-methylimidazol] copper complexes and by death receptors (extrinsic pathway) in case of MK0 [Cu2(N-sal-D,L-glu)2(isoquinoline)2].2H2O copper complex in HT-29.

Keywords: apoptosis, copper complex, cancer, carcinoma cell line

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Authors: Marinela Miclau, Melinda Vajda, Nicolae Miclau, Daniel Ursu

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Characterized by a simple structure, easy and low cost fabrication, the dye-sensitized solar cell (DSSC) attracted the interest of the scientific community as an attractive alternative of conventional Si-based solar cells and thin-film solar cells. Over the past 20 years, the main efforts have attempted to enhance the efficiency of n-type DSSCs, the highest efficiency record of 14.30% was achieved using the co-sensitization of two metal-free organic dyes and Co (II/III) tris(phenanthroline)-based redox electrolyte. In the last years, the development of the efficient p-type DSSC has become a research focus owing to the fact that the concept of tandem solar cell was proposed as the solution to increase the power conversion efficiency. A promising alternative for the photocathodes of p-type DSSC, cuprous (Cu2O) and cupric (CuO) oxides have been investigated because of its nontoxic nature, low cost, high natural abundance, a good absorption coefficient for visible light and a higher dielectric constant than NiO. In case of p-type DSSC based on copper oxides with I3-/I- as redox mediator, the highest conversion efficiency of 0.42% (Cu2O) and 0.03% (CuO) has achieved. Towards the increase in the performance, we have fabricated and analyzed the performance of p-type DSSC prepared with the binder-free porous Cu2O photocathodes. Porous thin film could be an attractive alternative for DSSC because of their large surface areas which enable the efficient absorption of the dyes and light. We propose a simple and one-step hydrothermal method for the preparation of porous Cu2O thin film using copper substrate, cupric acetate and ethyl cellulose. The cubic structure of Cu2O has been determined by X-ray diffraction (XRD) and porous morphology of thin film was emphasized by Scanning Electron Microscope Inspect S (SEM). Optical and Mott-Schottky measurements attest of the high quality of the Cu2O thin film. The binder-free porous Cu2O photocathode has confirmed the excellent photovoltaic properties, the best value reported for p-type DSSC (1%) in similar conditions being reached.

Keywords: cuprous oxide, dye-sensitized solar cell, hydrothermal method, porous photocathode

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Authors: Nasir Iqbal, Khurram Siraj, Rizwan Raza

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Solid oxide fuel cell (SOFC) is the promising technology now days. SOFC can be operated with different types of fuels available. In this work catalytic anode is prepared with metal oxides i.e. Li, Ni, Zn and Sn and tested for catalytic activity with natural gas as a fuel. The operating temperature range is 170-750°C as observed with the help of TGA. Electrical conductivity and fuel cell performance has been observed for four different samples with varying composition of Sn and Zn. It is concluded that the sample having greater concentration of Zn shows better conductivity and power density results. All the results are promising and verified with different characterizations.

Keywords: catalytic activity, solid oxide fuel cell, energy material, natural gas

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Authors: Neeraj Kumar Verma

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Lanthanum hydroxide and manganese oxide nanocomposite are synthesized by chemical routes. Physical characterization is done by TEM to look at the size and dispersion of the nanoparticles in the composite. Chemical characterization is done by X-ray diffraction technique and FTIR to ascertain the attachment of the functionalities and bond stretching. Further thermal analysis is done by thermogravimetric analysis to find the tendency of the thermal decomposition in the elevated temperature range of 0-1000°C. Proper analysis and correlation of the various results obtained suggested the controlled growth of crystalline without agglomeration and good stability in the various temperature ranges of the composite.

Keywords: nanoparticles, XRD, TEM, lanthanum hydroxide, manganese oxide

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Authors: Ming Liu, Chong Wu, Bingquan Liu, Lei Chen

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Internet users have to face the massive amount of textual data every day. Organizing texts into categories can help users dig the useful information from large-scale text collection. Clustering, in fact, is one of the most promising tools for categorizing texts due to its unsupervised characteristic. Unfortunately, most of traditional clustering algorithms lose their high qualities on large-scale text collection. This situation mainly attributes to the high- dimensional vectors generated from texts. To effectively and efficiently cluster large-scale text collection, this paper proposes a vector reconstruction based clustering algorithm. Only the features that can represent the cluster are preserved in cluster’s representative vector. This algorithm alternately repeats two sub-processes until it converges. One process is partial tuning sub-process, where feature’s weight is fine-tuned by iterative process. To accelerate clustering velocity, an intersection based similarity measurement and its corresponding neuron adjustment function are proposed and implemented in this sub-process. The other process is overall tuning sub-process, where the features are reallocated among different clusters. In this sub-process, the features useless to represent the cluster are removed from cluster’s representative vector. Experimental results on the three text collections (including two small-scale and one large-scale text collections) demonstrate that our algorithm obtains high quality on both small-scale and large-scale text collections.

Keywords: vector reconstruction, large-scale text clustering, partial tuning sub-process, overall tuning sub-process

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Authors: Deepika Sharma, Bal Krishan

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In this paper, the structure of N-channel VDMOS was designed and analyzed using Silvaco TCAD tools by varying N+ source doping concentration, P-Body doping concentration, gate oxide thickness and the diffuse time. VDMOS is considered to be ideal power switches due to its high input impedance and fast switching speed. The performance of the device was analyzed from the Ids vs Vgs curve. The electrical characteristics such as threshold voltage, gate oxide thickness and breakdown voltage for the proposed device structures were extarcted. Effect of epitaxial layer on various parameters is also observed.

Keywords: on-resistance, threshold voltage, epitaxial layer, breakdown voltage

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Authors: Mahdi Almaky, Reda Hassanin, Benjamin Horrocks, Andrew Houlton

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DNA-templated poly(N-substituted pyrrole)bipyridinium nanowires were synthesised at room temperature using the chemical oxidation method. The resulting CPs/DNA hybrids have been characterised using electronic and vibrational spectroscopic methods especially Ultraviolet-Visible (UV-Vis) spectroscopy and FTIR spectroscpy. The nanowires morphology was characterised using Atomic Force Microscopy (AFM). The electrical properties of the prepared nanowires were characterised using Electrostatic Force Microscopy (EFM), and measured using conductive AFM (c-AFM) and two terminal I/V technique, where the temperature dependence of the conductivity was probed. The conductivities of the prepared CPs/DNA nanowires are generally lower than PPy/DNA nanowires showingthe large effect on N-alkylation in decreasing the conductivity of the polymer, butthese are higher than the conductivity of their corresponding bulk films.This enhancement in conductivity could be attributed to the ordering of the polymer chains on DNA during the templating process. The prepared CPs/DNA nanowires were used as templates for the growth of copper nanowires at room temperature using aqueous solution of Cu(NO3)2as a source of Cu2+ and ascorbic acid as reducing agent. AFM images showed that these nanowires were uniform and continuous compared to copper nanowires prepared using the templating method directly onto DNA. Electrical characterization of the nanowires by c AFM revealed slight improvement in conductivity of these nanowires (Cu-CPs/DNA) compared to CPs/DNA nanowires before metallisation.

Keywords: templating, copper nanowires, polymer/DNA hybrid, chemical oxidation method

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Authors: Fuyan Sun, Guang Wang, Xueyuan Nie

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In this study, a plasma electrolytic oxidation (PEO) process was used to form titanium-aluminium oxide coating on aluminized steel. The present work was mainly to study the effects of treatment time of PEO process on properties of the titanium coating. A potentiodynamic polarization corrosion test was employed to investigate the corrosion resistance of the coating. The friction coefficient and wear resistance of the coating were studied by using pin-on-disc test. The thermal transfer behaviours of uncoated and PEO-coated aluminized steels were also studied. It could be seen that treatment time of PEO process significantly influenced the properties of the titanium oxide coating. Samples with a longer treatment time had a better performance for corrosion and wear protection. This paper demonstrated different treatment time could alter the surface behaviour of the coating material.

Keywords: titanium-aluminum oxide, plasma electrolytic oxidation, corrosion, wear, thermal property

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Authors: S. Rasti, M. A. Rajabzadeh

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Nickel-bearing laterites occur as two parallel belts along Sedimentary Zagros Orogenic (SZO) and Metamorphic Sanandaj-Sirjan (MSS) petrostructural zones, Fars Province, south Iran. An undisturbed vertical profile of these laterites includes protolith, saprolite, clay, and oxide horizons from base to top. Highly serpentinized harzburgite with relicts of olivine and orthopyroxene is regarded as the source rock. The laterites are unusual in lacking a significant saprolite zone with little development of Ni-silicates. Hematite, saponite, dolomite, smectite and clinochlore increase, while calcite, olivine, lizardite and chrysotile decrease from saprolite to oxide zones. Smectite and clinochlore with minor calcite are the major minerals in clay zone. Contacts of different horizons in laterite profiles are gradual and characterized by a decrease in Mg concentration ranging from 18.1 to 9.3 wt.% in oxide and saprolite, respectively. The maximum Ni concentration is 0.34 wt.% (NiO) in the base of the oxide zone, and goethite is the major Ni-bearing phase. From saprolite to oxide horizons, Al₂O₃, K₂O, TiO₂, and CaO decrease, while SiO₂, MnO, NiO, and Fe₂O₃ increase. Silica content reaches up to 45 wt.% in the upper part of the soil profile. There is a decrease in pH (8.44-8.17) and an increase in organic matter (0.28-0.59 wt.%) from base to top of the soils. The studied laterites are classified in the oxide clans which were derived from ophiolite ultramafic rocks under Mediterranean climate conditions.

Keywords: Iran, laterite, mineralogy, ophiolite

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Authors: Loai Ben Naji, Osama M. Ibrahim, Khaled J. Al-Fadhalah

Abstract:

The objective of this paper is to investigate the formation and adhesion of a protective aluminum-oxide (Al₂O₃, alumina) layer on the surface of Iron-Chromium-Aluminum Alloy (Fe-Cr-Al) sintered-metal-fibers. The oxide-scale layer was developed via multi-stage thermal oxidation at 930 ^oC for 1 hour, followed by 1 hour at 960 ^oC, and finally at 990 ^oC for 2 hours. Scanning Electron Microscope (SEM) images show that the multi-stage thermal oxidation resulted in the formation of predominantly Al₂O₃ platelets-like and whiskers. SEM images also reveal non-uniform oxide-scale growth on the surface of the fibers. Furthermore, peeling/spalling of the alumina protective layer occurred after minimum handling, which indicates weak adhesion forces between the protective layer and the base metal alloy.  Energy Dispersive Spectroscopy (EDS) analysis of the heat-treated Fe-Cr-Al sintered-metal-fibers confirmed the high aluminum content on the surface of the protective layer, and the low aluminum content on the exposed base metal alloy surface. In conclusion, the failure of the oxide-scale protective layer exposes the base metal alloy to further oxidation, and the fragile non-uniform oxide-scale is not suitable as a support for catalysts.

Keywords: high-temperature oxidation, iron-chromium-aluminum alloy, alumina protective layer, sintered-metal-fibers

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Authors: Nassima Khanfri, Ali Boucenna

Abstract:

As metallic nanoparticles are increasingly used in many economic sectors, there is interest in the biological and environmental safety of their production. The main methods of synthesizing nanoparticales are chemical and physical approaches that are often expensive and potentially harmful to the environment. The present study is devoted to the possibility of the synthesis of silver nanoparticales and zinc oxide from silver nitrate and zinc acetate using basilica plant extracts. The products obtained are characterized by various analysis techniques, such as UV/V, XRD, MEB-EDX, FTIR, and RAMAN. These analyzes confirm the crystalline nature of AgNps and ZnONps. These crystalline powders having effective biological activities regarding the antioxidant and antibacterial, which could be used in several biological applications.

Keywords: green synthesis, bio-reduction, metals nan Oparticales, Plants extracts

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Authors: Yu-Ting Tsai, Chiun-Chieh Hsu, Yu-Chun Chu

Abstract:

In recent years, due to the development of wireless network technology, many researchers have devoted to the study of wireless sensor networks. The applications of wireless sensor network mainly use the sensor nodes to collect the required information, and send the information back to the users. Since the sensed area is difficult to reach, there are many restrictions on the design of the sensor nodes, where the most important restriction is the limited energy of sensor nodes. Because of the limited energy, researchers proposed a number of ways to reduce energy consumption and balance the load of sensor nodes in order to increase the network lifetime. In this paper, we proposed the Energy-Balanced Clustering method with Auxiliary Members on Wireless Sensor Networks（EBCAM）based on the cluster routing. The main purpose is to balance the energy consumption on the sensed area and average the distribution of dead nodes in order to avoid excessive energy consumption because of the increasing in transmission distance. In addition, we use the residual energy and average energy consumption of the nodes within the cluster to choose the cluster heads, use the multi hop transmission method to deliver the data, and dynamically adjust the transmission radius according to the load conditions. Finally, we use the auxiliary cluster members to change the delivering path according to the residual energy of the cluster head in order to its load. Finally, we compare the proposed method with the related algorithms via simulated experiments and then analyze the results. It reveals that the proposed method outperforms other algorithms in the numbers of used rounds and the average energy consumption.

Keywords: auxiliary nodes, cluster, load balance, routing algorithm, wireless sensor network

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Authors: Vivek Anand, Rainer Naegele

Abstract:

Industry 4.0 is a global mega-trend revolutionizing the world of advanced manufacturing, but also bringing up challenges for SMEs. In response, many regional, as well as digital Industry 4.0 Platforms, have been set up to boost the competencies of established enterprises as well as SMEs. The concept of 'Clusters' is a policy tool that aims to be a starting point to establish sustainable and self-supporting structures in industries of a region by identifying competencies and supporting cluster actors with services that match their growth needs. This paper is motivated by the idea that Clusters have the potential to enable firms, particularly SMEs, to accelerate the innovation process and transition to digital technologies. In this research, the efficacy of Industry 4.0 platforms as Cluster ecosystems is evaluated, especially for SMEs. Focusing on the Baden Wurttemberg region in Germany, an action research method is employed to study how SMEs leverage other actors on Industry 4.0 Platforms to further their Industry 4.0 journeys. The aim is to evaluate how such Industry 4.0 platforms stimulate innovation, cooperation and competitiveness. Additionally, the barriers to these platforms fulfilling their promise to serve as capacity building cluster ecosystems for SMEs in a region will also be identified. The findings will be helpful for academicians and policymakers alike, who can leverage a ‘cluster policy’ to enable Industry 4.0 ecosystems in their regions. Furthermore, relevant management and policy implications stem from the analysis. This will also be of interest to the various players in a cluster ecosystem - like SMEs and service providers - who benefit from the cooperation and competition. The paper will improve the understanding of how a dialogue orientation, a bottom-up approach and active integration of all involved cluster actors enhance the potential of Industry 4.0 Platforms. A strong collaborative culture is a key driver of digital transformation and technology adoption across sectors, value chains and supply chains; and will position Industry 4.0 Platforms at the forefront of the industrial renaissance. Motivated by this argument and based on the results of the qualitative research, a roadmap will be proposed to position Industry 4.0 Platforms as effective clusters ecosystems to support Industry 4.0 adoption in a region.

Keywords: cluster policy, digital transformation, industry 4.0, innovation clusters, innovation policy, SMEs and startups

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Authors: Ankush Raina, Ankush Anand

Abstract:

Plyometric training is a form of specialised strength training that uses fast muscular contractions to improve power and speed in sports conditioning by coaches and athletes. Despite its useful role in sports conditioning programme, the information about plyometric training on the athletes cardiovascular health especially Electrocardiogram (ECG) has not been established in the literature. The purpose of the study was to determine the effects of lower and upper body plyometric training on ECG of athletes. The study was guided by three null hypotheses. Quasi–experimental research design was adopted for the study. Seventy-two university male athletes constituted the population of the study. Thirty male athletes aged 18 to 24 years volunteered to participate in the study, but only twenty-three completed the study. The volunteered athletes were apparently healthy, physically active and free of any lower and upper extremity bone injuries for past one year and they had no medical or orthopedic injuries that may affect their participation in the study. Ten subjects were purposively assigned to one of the three groups: lower body plyometric training (LBPT), upper body plyometric training (UBPT), and control (C). Training consisted of six plyometric exercises: lower (ankle hops, squat jumps, tuck jumps) and upper body plyometric training (push-ups, medicine ball-chest throws and side throws) with moderate intensity. The general data were collated and analysed using Statistical Package for Social Science (SPSS version 22.0). The research questions were answered using mean and standard deviation, while paired samples t-test was also used to test for the hypotheses. The results revealed that athletes who were trained using LBPT had reduced ECG parameters better than those in the control group. The results also revealed that athletes who were trained using both LBPT and UBPT indicated lack of significant differences following ten weeks plyometric training than those in the control group in the ECG parameters except in Q wave, R wave and S wave (QRS) complex. Based on the findings of the study, it was recommended among others that coaches should include both LBPT and UBPT as part of athletes’ overall training programme from primary to tertiary institution to optimise performance as well as reduce the risk of cardiovascular diseases and promotes good healthy lifestyle.

Keywords: boundary lubrication, copper oxide, friction, nano diamond

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Authors: S. Chockalingam, U. Natarajan, D. M. Santhoshsarang

Abstract:

Particle damping is a promising vibration attenuating technique in boring tool than other type of damping with minimal effect on the strength, rigidity and stiffness ratio of the machine tool structure. Due to the cantilever nature of boring tool holder in operations, it suffers chatter when the slenderness ratio of the tool gets increased. In this study, Copper-Stainless steel (SS) particles were packed inside the boring tool which acts as a damper. Damper suppresses chatter generated during machining and also improves the machining efficiency of the tool with better slenderness ratio. In the first approach of particle damping, combined Cu-SS particles were packed inside the vibrating tool, whereas Copper and Stainless steel particles were selected separately and packed inside another tool and their effectiveness was analysed in this simulation. This study reveals that the efficiency of finite element simulation of the boring tools when equipped with particles such as copper, stainless steel and a combination of both. In this study, the newly modified boring tool holder with particle damping was simulated using ANSYS12.0 with and without particles. The aim of this study is to enhance the structural rigidity through particle damping thus avoiding the occurrence of resonance in the boring tool during machining.

Keywords: boring bar, copper-stainless steel, chatter, particle damping

Procedia PDF Downloads 426