bluuebunny/crossref_metadata_2025 huggingface dataset:
Bis[tetrakis(pyridin-2-yl)methane-κ3N,N′,N′′]cobalt(II) tetrakis(thiocyanato-κN)cobaltate(II) methanol monosolvate
Authors: Tsunezumi Yuya , Matsumoto Kouzou , Hayami Shinya , Fuyuhiro Akira , Kawata Satoshi
Published: February 2014

The title complex, [Co(C21H16N4)2][Co(NCS)4]·CH3OH, consists of one [Co{C(py)4}2]2+complex cation [C(py)4= tetrakis(pyridin-2-yl)methane], one [Co(NCS)4]2−complex anion and a methanol solvent molecule. In the cation, the CoIIatom is coordinated by six N atoms of two C(py)4ligands in a distorted octahedral geometry. In the anion, the CoIIatom is coordinated by the N atoms of four NCS−ligands in a distorted tetrahedral geometry. The methanol molecule is disordered and was modelled over three orientations (occupancies 0.8:0.1:0.1). There are two weak hydrogen-bond-like interactions between the methanol solvent molecule and NCS−ligands of the anion [O...S = 3.283 (3) and 3.170 (2) Å].
[N,N′-Bis(2,6-diethyl-4-phenylphenyl)butane-2,3-diimine-κ2N,N′]dibromidonickel(II)
Authors: Yuan Jianchao , Xia Jingjing , Xu Weibing , Mu Yanqiong
Published: February 2014

The complex molecule in the title compound, [NiBr2(C36H40N2)], has mirror symmetry. The NiIIatom and two Br atoms are located on the mirror plane. The NiIIatom is four-coordinated by the two Br atoms and two N atoms from anN,N′-bis(2,6-diethyl-4-phenylphenyl)butane-2,3-diimine ligand in a distorted tetrahedral geometry. The dihedral angle formed between the two adjacent benzene rings is 47.1 (1)°.
(Dimethylphosphoryl)methanaminium hydrogen oxalate–oxalic acid (2/1)
Authors: Bialek Sebastian , Clemens Rebecca , Reiss Guido J.
Published: February 2014

The reaction of (dimethylphosphoryl)methanamine (dpma) with oxalic acid in ethanol yielded the title solvated salt, C3H11NOP+·C2HO4−·0.5C2H2O4. Its asymmetric unit consists of one dpmaH+cation, one hydrogen oxalate anion and a half-molecule of oxalic acid located around a twofold rotation axis. The H atom of the hydrogen oxalate anion is statistically disordered over two positions that aretransto each other. The hydrogen oxalate monoanion is not planar (bend angle ∼16°) whereas the oxalic acid molecule shows a significantly smaller bend angle (∼7°). In the crystal, the components are connected by strong O—H...O and much weaker N—H...O hydrogen bonds, leading to the formation of layers extending parallel to (001). The structure was refined from a racemically twinned crystal with twin components in an approximate 1:1 ratio.
4-Nitrophthalamide
Authors: Jan Chin Yee , Shamsudin Norzianah Binti Haji , Tan Ai Ling , Young David J. , Ng Seik Weng , Tiekink Edward R. T.
Published: February 2014

In the title compound, C8H7N3O4(systematic name: 4-nitrobenzene-1,2-dicarboxamide), each of the substituents is twisted out of the plane of the benzene ring to which it is attached [dihedral angles of 11.36 (2)° for the nitro group, and 60.89 (6) and 34.39 (6)° for the amide groups]. The amide groups are orientated to either side of the least-squares plane through the benzene ring with the amine groups being directed furthest apart. In the crystal, a three-dimensional architecture is established by a network of N—H...O hydrogen bonds.
Methyl 4′-(3-bromophenyl)-3′-(2,5-dimethylbenzyl)-1′-methyl-2-oxospiro[indoline-3,2′-pyrrolidine]-3′-carboxylate
Authors: Karthikeyan S. , Sethusankar K. , Devaraj Anthonisamy , Bakthadoss Manickam
Published: February 2014

In the title compound, C29H29BrN2O3, the indole ring system is essentially planar (r.m.s. deviation = 0.079 Å) and makes a dihedral angle of 85.23 (10)° with the mean plane of the 4-methylpyrrolidine ring. This ring adopts an envelope conformation with the N atom at the flap. The pyrrolidine ring of the indole ring system adopts a twisted conformation on the C—C(=O) bond. The molecular structure is stabilized by an intramolecular C—H...O hydrogen bond, which generates anS(6) ring motif. In the crystal, molecules are linkedviapairs of C—H...O hydrogen bonds, forming inversion dimers with anR22(14) ring motif. These dimers are further linked by N—H...O and C—H...O hydrogen bonds, forming two-dimensional networks lying parallel to (10-1).
Bis[(2-methylbenzyl)bis(pyridin-2-ylmethyl-κN)amine-κN]manganese(II) bis(perchlorate)
Authors: Butcher Ray J. , Gultneh Yilma , Yisgedu T. B.
Published: February 2014

In the title complex, [Mn(C20H21N3)2](ClO4)2, two tridentate (2-methylbenzyl)bis(pyridin-2-ylmethyl)amine (L) ligands form the MnIIcomplex [MnL2](ClO4)2. The MnIIion lies on a twofold axis and the complex cation is significantly distorted from regular octahedral geometry. The packing is stabilized by weak C—H...O interactions between the cations and anions, which link them into a zigzag ribbon along [101]. The perchlorate anion is disordered and was constrained to be tetrahedral with two orientations having occupancies of 0.768 (4) and 0.232 (4). The 2-methylbenzyl moiety is also disordered over two sets of sites, with occupancies of 0.508 (15) and 0.492 (15).
Dimethyl 2,2′-dinitrobiphenyl-4,4′-dicarboxylate
Authors: Lehane Ryan L. , Golen James A. , Rheingold Arnold L. , Manke David R.
Published: February 2014

The title compound, C16H12N2O8, exhibits two near-planar aromatic ester groups with aryl–ester dihedral angles of 2.1 (2) and 4.2 (3)°. The dihedral angle between the aromatic rings is 58.0 (1)°. The two nitro groups are tilted slightly from the plane of the aromatic rings, making dihedral angles of 14.1 (1) and 8.2 (2)°. In the crystal, molecules are connected by weak C—H...O interactions, forming a three-dimensional network.
N-Methyl-2-(1,2,3,4-tetrahydronaphthalen-1-ylidene)hydrazinecarbothioamide
Authors: Oliveira Adriano Bof de , Feitosa Bárbara Regina Santos , Näther Christian , Jess Inke
Published: February 2014

There are two independent molecules in the asymmetric unit of the title compound, C12H15N3S, both of which display disorder of several C atoms in the N-bound ring (occupancy ratios of 0.75:0.25 in the first independent molecule and 0.50:0.50 in the second) with the methyl H atoms also being disordered in the first molecule (occupancy ratio of 0.70:0.30). The planes of the benzene ring and the N—N—C—N fragment make dihedral angles of 12.92 (14)° in the first independent molecule and 7.60 (13)° in the second. In the crystal, molecules are linked by weak N—H...S hydrogen bonds into chains along thea-axis direction. The crystal packing ressembles a herringbone arrangement.
3-(3-Bromophenylsulfinyl)-5-cyclohexyl-2-methyl-1-benzofuran
Authors: Choi Hong Dae , Seo Pil Ja , Lee Uk
Published: February 2014

In the title compound, C21H21BrO2S, the cyclohexyl ring adopts a chair conformation. The dihedral angle between the mean plane [r.m.s. deviation = 0.178 (2) Å] of the benzofuran ring system and the mean plane of the 3-bromophenyl ring is 86.52 (6)°. In the crystal, molecules are linked by weak C—H...O and C—H...π hydrogen bonds, and by a slipped π–π interaction between the furan rings of neighbouring molecules [centroid–centroid distance = 3.518 (3) Å, interplanar distance = 3.471 (3) Å and slippage = 0.573 (3) Å], resulting in a three-dimensional network.
Ethyl 3-[7-(N-acetyl-4-methoxybenzenesulfonamido)-3-chloro-2H-indazol-2-yl]propionate
Authors: Kouakou Assoman , Rakib El Mostapha , Abbassi Najat , Saadi Mohamed , El Ammari Lahcen
Published: February 2014

In the title compound, C21H22ClN3O6S, the fused five- and six-membered ring rings are almost perpendicular to the planes through the atoms forming the acetyl and the propionic ester groups, as indicated by the dihedral angles of 80.3 (2) and 88.3 (7)°, respectively. The dihedral angle between the indazole system and the 4-methoxybenzenesulfonyl group is 13.76 (6)°. The carbonyl O atom is split over two positions in a 0.60 (5):0.40 (5) ratio. In the crystal, molecules are linked by C—H...O and C—H...N interactions into a three-dimensional network.
Overseas listing location and capital structure
Authors: Li Peixin , Wang Baolian
Published: February 2014

Purpose

– A significant number of Chinese companies are listed overseas. The authors aim to examine whether overseas locations affect their financing decision, specifically their capital structure choice.

Design/methodology/approach

– Most of the Chinese overseas listed companies are listed in the USA and Hong Kong. As the institutional quality of the USA is better than Hong Kong, the authors, therefore, choose to build the hypotheses from the “law and finance” literature. Specifically, the authors argue that the better institutional environment of the USA can mitigate the information asymmetry problem and the agency problem of financing via equity. Consequently, firms listed in the USA will rely more on equity and have lower leverage ratio. The difference in leverage ratio of US listed and Hong Kong listed companies should be larger when the marginal benefit of better information environment is larger.

Findings

– Referring to various data sources, the authors construct a comprehensive list of overseas listed companies in the USA and Hong Kong. The authors collect the accounting and stock performance information from Datastream/Worldscope and the equity offering data from Global New Issue database. The empirical findings provide strong support of the hypotheses: the leverage is 15 percent lower for US listed companies than the Hong Kong listed companies; the results are stronger when the firms face more severe information asymmetry problem; the stock price reacts less negatively for seasoned equity offering in the USA than in Hong Kong.

Practical implications

– Most of the Chinese companies decided to be listed overseas because they cannot be listed in the Mainland Chinese stock exchanges. One of the most important motivation is to access to external capital to support firm growth. As the main channel of external financing in the overseas markets is equity since debt is still mainly domestically based, one implication of this paper is that Chinese companies can gain better access to external capital in the USA than in Hong Kong and relax their financial constraint.

Originality/value

– There are a considerable number of Chinese companies listed in the overseas markets. Many successful and famous companies are among them. However, almost no research has been done based on them. This paper documents some very important phenomenon of this market. The authors wish that more studies will be conducted. In addition, the study also complements the existing studies on how institutional environment affects corporate financial behavior.
Assessment on RMB valuation – a triangular analysis approach
Authors: Wang Peijie , Zhang Bing
Published: February 2014

Purpose

– The authors make assessment on RMB valuation and to contribute to the fierce debate on this important issue, which is perceived to have a great effect on the improvement or deterioration in trade balance. A triangular analysis approach is put forward and empirical assessment is made. The paper aims to discuss these issues.

Design/methodology/approach

– A triangular analysis approach based on no arbitrage conditions for three currencies, and causality and influence analysis.

Findings

– First, it has been found that the movements in the RMB dollar exchange rate do influence the dollar euro exchange rate and the former do have a causality effect on the latter, in both the long run and the short term. Second, it is implied that the RMB is overvaluedvis-à-visthe US dollar, as the analysis suggests that an overvalued eurovis-à-visthe US dollar would imply a kind of overvaluation of the RMBvis-à-visthe US dollar, and by any conventional measures the euro has appeared to be overvaluedvis-à-visthe US dollar, especially in the months before the last financial crisis.

Practical implications

– First, the peg of the RMB to the US dollar that undervalues the RMBvis-à-visthe US dollar will not help promote China's overall trade balance or export even if undervaluation of currencies can ever help improve nations' terms of trade. Second, no stability in RMB exchange rates can be claimed by pegging the RMB to the US dollar, as the exchange rate of the RMBvis-à-viscurrencies other than the US dollar would be as volatile as that between the US dollar and the euro and other convertible currencies.

Originality/value

– A new triangular analysis approach in international finance research. First, there is an advantage to adopt this seemingly simple analytical framework: it is highly reliable; no triangular arbitrage conditions have to be met even under exchange controls, whilst PPP may not hold even with flexible exchange rate regimes. Second, it does away with the thinking confined to small open economies that has dominated academic research for so long and is totally inapplicable to the RMB case.
Testing asymmetric correlations in stock returns via empirical likelihood method
Authors: Pan Zhiyuan , Zheng Xu , Chen Qiang
Published: February 2014

Purpose

– This study aims to propose a model-free statistic that tests asymmetric correlations of stock returns, in which stocks move more often with the market when the market goes down than when it goes up, and then empirically analyze the asymmetric correlations of the China stock market and international stock markets, respectively.

Design/methodology/approach

– Using empirical likelihood method, this study designs and conducts a model-free test, which converges to χ2 distribution under regulated conditions and performs well in the finite sample using bootstrap critical value method.

Findings

– By analyzing the authors' model-free test, the authors find that compared with Hong et al.'s test that closely relates to the authors, both of the tests are under rejected using asymptotic critical value. However, using the bootstrap critical value method can greatly improve the performance of the two tests. Second, investigating the power of the two tests, the authors find that the proportion of rejections of the authors' test is roughly 10-20 percent larger than Hong et al.'s test in mixed copula model setting. The last finding is the authors find evidence of asymmetric for small-cap size portfolios, but no evidence for middle-cap and large-cap size portfolios in the China stock market. Besides, the authors test asymmetric correlations between the USA and Japan, France and the UK; the asymmetric phenomenon exists in international stock markets, which is similar to Longin and Solnik's findings, but they are not significant according to both the authors' test and Hong et al.'s test.

Research limitations/implications

– The findings in this study suggest that both the authors' test and Hong et al.'s test are under rejected using asymptotic critical value. When applying these statistics to test asymmetric correlations, the authors should take care with the choice of critical value.

Practical implications

– The empirical analysis has a significant practical implication for asset allocation, asset pricing and risk management fields.

Originality/value

– This study constructs a model-free statistic to test asymmetric correlations using empirical likelihood method for the first time and corrects the size performance by bootstrap method, which improves the performance of Hong et al.'s test. To the authors' knowledge, this is the first study to test the asymmetric correlations in the China stock market.
Macro-factors on gold pricing during the financial crisis
Authors: Fan Wei , Fang Sihai , Lu Tao
Published: February 2014

Purpose

– This study aims to propose the idea of which macro-factors and how the macro-factors impact on the gold price.

Design/methodology/approach

– An EGARCH model is applied to test the volatility of gold price. A VAR method is applied to validate the idea by decomposing gold's value into three parts according to its features.

Findings

– Three macro-factors have significant impact on the gold's price. The USDX index is negatively correlated with the gold price, while the CRB index and the US Treasury CDS spreads are positively correlated with the gold price. In particular, it is found that the one-lagged CRB index, one-lagged USDX index, and two-lagged US Treasury CDS spreads have significant impact on the gold price.

Research limitations/implications

– The findings in this study suggest a normal case of the gold price. However, in particular cases, new models or new parameters may need to be introduced.

Practical implications

– This paper bridges the gap between theory and practice on the gold pricing model. The three-factor model can be used for trading in the field of gold investment.

Originality/value

– This paper provides a composite idea for investors and researchers to study the gold price.
Transient mixed convection flow of nanofluids in a vertical tube
Authors: Viorel Popa Catalin , Tam Nguyen Cong , Fohanno Stéphane , Polidori Guillaume
Published: February 2014

Purpose

– In the present work, a theoretical model based on the full Navier-Stokes and energy equations for transient mixed convection in a vertical tube is extended to nanofluids with nanoparticle volume fraction up to 5 percent to ensure a Newtonian fluid behaviour. The paper aims to discuss these issues.

Design/methodology/approach

– The nanofluids considered, alumina/water and CuO/water, flow inside a vertical tube of circular cross-section, which is subjected to convective heat exchange at the outer surface. The transient regime is caused by a sudden change of nanofluid temperature at the tube inlet. The range of the Richardson number (1.6=Ri=2.5) investigated in this study corresponds to classic cases of mixed convection flow.

Findings

– Results have shown a significant reduction in the size of the recirculation zone near the wall when the particle volume fraction increases. This may be attributed to the viscosity increase with the volume fraction. Moreover, the flow structure clearly changes when the convective heat transfer coefficient is modified. A decrease of the wall temperature along the tube was found when increasing the convective heat transfer coefficient imposed at the tube external surface.

Research limitations/implications

– The problem formulation in 2D axisymmetric geometry includes the continuity, the Navier-Stokes and energy equations and is based on the stream function and vorticity; the numerical solution of equations is carried out using a finite difference method.

Practical implications

– From an economic point of view, this research paper is innovative in the sense that it considers nanofluids as a new and more efficient way to transfer heat. This paper could find applications for heat exchange purposes of compact systems with high thermal loads.

Originality/value

– Across the world, a still growing number of research teams are investigating nanofluids and their properties. Investigations concern several aspects such as the preparation of the nanofluids, as well as the applications of these nanofluids for convective heat transfer purposes. The dynamical study will consist in the instantaneous and spatial characterization of the dynamic flow field for different nanoparticle volume fractions.
Three-dimensional stretched flow via convective boundary condition and heat generation/absorption
Authors: Hayat Tasawar , Ali Shehzad Sabir , Qasim Muhammad , Asghar Saleem
Published: February 2014

Purpose

– The purpose of this paper is to investigate the three-dimensional flow of viscous fluid with convective boundary conditions and heat generation/absorption.

Design/methodology/approach

– The governing partial differential equations are reduced into ordinary differential equations by applying similarity transformations. Series solutions of velocity and temperature are found by adopting homotopy analysis method (HAM).

Findings

– The authors found that an increase in ratio parameter and Hartman number increased the values of skin-friction coefficient, but the values of local Nusselt number are reduced with an increase in Hartman number.

Practical implications

– The present study is a useful source of information for the investigators in the fields of Newtonian fluids and heat transfer. The results obtained are specifically important in processes of polymer industry and metallurgical.

Originality/value

– Very scarce literature is available on three-dimensional stretched flow with convective boundary conditions. Mathematical modelling for such flow in regime of magnetohydrodynamics is a main concern here. Performed computations to the resulting nonlinear analysis further enhance its novelty.
Soret-Dufour effects on MHD rotating flow of a viscoelastic fluid
Authors: Hayat T. , Naz R. , Asghar S. , Alsaedi A.
Published: February 2014

Purpose

– The purpose of this paper is to study the heat and mass transfer with Soret-Dufour effects for the magnetohydrodynamic three-dimensional flow of second grade fluid in the rotating frame of reference.

Design/methodology/approach

– Series solution is obtained by homotopy analysis method.

Findings

– Increase in Soret number, Schmidt number and Dufour number, the heat transfer increases and mass transfer decreases. Effects of Prandtl and Eckert numbers are qualitatively similar as they assist the temperature profile and reduce the concentration of species. Increase in the length of the channel versus height increases the temperature profile but decreases the concentration field. Increase in the second grade fluid parameter causes reduction in both the temperature and concentration fields. The heat flux values at the lower plate are smaller than the values at the upper plate, whereas the situation is opposite in the case of mass transfer.

Originality/value

– These findings will be useful for the fluid flow in porous channel.
Time-dependent flow of UCM fluid with chemical reaction, thermal-diffusion and diffusion-thermo effects
Authors: Awais M. , Alsaedi A. , Hayat T.
Published: February 2014

Purpose

– The authors presented the time-dependent flow of an upper-convected Maxwell (UCM) fluid in the presence of chemical reaction, thermal-diffusion and diffusion-thermo effects. The paper aims to discuss these issues.

Design/methodology/approach

– Recent technique namely homotopy analysis method (HAM) is utilized to compute the solution of the problem.

Findings

– Chemical reaction has opposite effects on the concentration field for the destructive and constructive cases. The Deborah number acts as a retarding agent.

Originality/value

– Combined effects of thermal-diffusion, diffusion-thermo and chemical reaction are analyzed.
An analytic solution of micropolar flow in a porous channel with mass injection using homotopy analysis method
Authors: Hassan Hany , Mehdi Rashidi Mohammad
Published: February 2014

Purpose

– The paper aims to find an accurate analytic solution (series solution) for the micropolar flow in a porous channel with mass injection for different values of Reynolds number.

Design/methodology/approach

– In this paper, the homotopy analysis method (HAM) with different numbers of unknown convergence-control parameters has been used to derive accurate analytic solution for micropolar flow in a porous channel with mass injection. The possible optimal value of convergence-control parameter determined by minimizing the averaged residual error.

Findings

– The results obtained from HAM solution with two parameters are compared with numerical results and that obtained from HAM solution with only one parameter. The results show that this method gives an analytical solution with high order of accuracy with a few iterations. As shown in this paper, by minimizing the averaged residual error, the authors can get the possible optimal value of the convergence-control parameters which may give the fastest convergent series.

Practical implications

– The HAM with different numbers of unknown convergence-control parameters can be used to obtain analytic solutions for many problems in sciences and engineering.

Originality/value

– This paper fulfils an identified need to evaluate the accurate analytic solution (series solution) of practical problem.
Large eddy simulations of the influence of piston position on the swirling flow in a model two-stroke diesel engine
Authors: Obeidat Anas , Schnipper Teis , M. Ingvorsen Kristian , Haider Sajjad , Erik Meyer Knud , Mayer Stefan , H. Walther Jens
Published: February 2014

Purpose

– The purpose of this paper is to study the effect of piston position on the in-cylinder swirling flow in a simplified model of a large two-stroke marine diesel engine.

Design/methodology/approach

– Large eddy simulations with four different models for the turbulent flow are used: a one-equation model, a dynamic one-equation model, a localized dynamic one-equation model and a mixed-scale model. Simulations are carried out for two different geometries corresponding to 100 and 50 percent open scavenge ports.

Findings

– It is found that the mean tangential profile inside the cylinder changes qualitatively with port closure from a Lamb-Oseen vortex profile to a solid body rotation, while the axial velocity changes from a wake-like profile to a jet-like profile. The numerical results are compared with particle image velocimetry measurements, and in general, the authors find a good agreement.

Research limitations/implications

– Considering the complexity of the real engine, the authors designed the engine model using the simplest configuration possible. The setup contains no moving parts, the combustion is neglected and the exhaust valve is discarded.

Originality/value

– Studying the flow in a simplified engine model, the setup allows studies of fundamental aspects of swirling flow in a uniform scavenged engine. Comparing the four turbulence models, the local dynamic one-equation model is found to give the best agreement with the experimental results.
Analytic and numeric solutions for stagnation-point flow with melting, thermal-diffusion and diffusion-thermo effects
Authors: Awais M. , Hayat T. , Mustafa M. , Bhattacharyya K. , Asif Farooq M.
Published: February 2014

Purpose

– The aim of this work is to analyze the combined effects of melting, thermal-diffusion and diffusion-thermo on the flow of non-Newtonian fluid.

Design/methodology/approach

– An efficient approach namely homotopy analysis method is applied to compute the solution of the non-linear problem. Moreover, numerical results using MATLAB function bvp4c are also computed.

Findings

– Main findings are an increase in the melting process corresponding to increase in the velocity and the boundary layer thickness. However, surface heat and mass transfer decrease by increasing the values of melting parameter M.

Originality/value

– Combined effects of thermal-diffusion and diffusion-thermo are analyzed and the solutions are computed both numerically and analytically. Some deduced results can be obtained in a limiting sense.
Finite volume formulation of thermal lattice Boltzmann method
Authors: Zarghami Ahad , Ubertini Stefano , Succi Sauro
Published: February 2014

Purpose

– The main purpose of this paper is to develop a novel thermal lattice Boltzmann method (LBM) based on finite volume (FV) formulation. Validation of the suggested formulation is performed by simulating plane Poiseuille, backward-facing step and flow over circular cylinder.

Design/methodology/approach

– For this purpose, a cell-centered scheme is used to discretize the convection operator and the double distribution function model is applied to describe the temperature field. To enhance stability, weighting factors are defined as flux correctors on a D2Q9 lattice.

Findings

– The introduction of pressure-temperature-dependent flux-control coefficients in the streaming operator, in conjunction with suitable boundary conditions, is shown to result in enhanced numerical stability of the scheme. In all cases, excellent agreement with the existing literature is found and shows that the presented method is a promising scheme in simulating thermo-hydrodynamic phenomena.

Originality/value

– A stable and accurate FV formulation of the thermal DDF-LBM is presented.
Taking off the L-plates: making training more effective
Authors: McCrae Bryan
Published: February 2014

Purpose

– Emphasizes the importance of ensuring the right training and the right delivery.

Design/methodology/approach

– Draws on information gathered from the author's industry knowledge and experience.

Findings

– Argues that senior managers sometimes fail to understand how training needs to be different to meet the expectations and requirements of the different personalities in the organization.

Practical implications

– Explains how using flooding or drip-feed techniques will have different outcomes for different personalities and helps managers to identify which is more suitable.

Originality/value

– Deals with what happens once the training is finished: taking off the L-plates, so to speak.
It's not all perfection at Paradise Retail
Authors: Joshi Gowri , Pande Sharon
Published: February 2014

Purpose

– Observes a number of human-resource management problems in the Indian hand-loom industry.

Design/methodology/approach

– Considers what gave rise to the problems and considers how they may be solved.

Findings

– Highlights the need to: attract talented designers with the right values and alignment to the company vision; refine training strategies to make them need-based and relevant; attract the right artisans; enhance productivity levels; standardize pricing and quality of products; and preserve art and craft to sustain the business.

Practical implications

– Presents a number of review questions. In what way can a firm like Paradise differ from other retailers? Define some realistic strategies to combat the problems of Paradise Retail. Which will be cost-effective? What can be gauged about the organizational culture of Paradise Retail? What are its values?

Originality/value

– Deals with some of the problems of poorly paid workers in a traditional industry in a developing country.
Stick-slip properties of single and multiple yarn pull-out in dry and softening treated polyester satin woven fabrics in boundary region
Authors: Bilisik Kadir , Yildirim Bekir
Published: February 2014

Purpose

– The aim of this study was to understand the stick-slip properties of single and multiple yarn pull-out in dry and treated polyester satin woven fabric in boundary regions.

Design/methodology/approach

– Polyester satin pattern woven fabric was used to conduct the pull-out tests in order to examining the kinetic region of the force-displacement curve. Data generated from this research help the authors to obtain stick-slip force and accumulative retraction force.

Findings

– It was found that stick-slip force and accumulative retraction force depend on the number of pulled ends in the fabric, fabric sample dimensions and softening treatments. Stick-slip forces of polyester satin fabric in the multiple yarn pull-out test were higher than those of the single yarn pull-out test. Stick-slip force in single and multiple yarn pull-out tests in the dry polyester satin fabric was generally higher than those of the softening treated polyester satin fabric. In addition, the warp directional single and multiple yarn stick-slip and accumulative retraction forces in the dry and softening treated polyester fabrics were generally higher than those in the weft direction in the fabric edges due to fabric density. On the other hand, the amount of stick-slip force was related to the number of interlacement points in the fabric, whereas the amount of accumulative retraction force was related to fabric structural response.

Originality/value

– The mechanism of stick-slip and accumulative retraction force of dry-treated polyester satin pattern woven fabrics were explained. This research could be valuable for development of multifunctional fabrics in technical textiles and ballistic.
Effects of plasma pre-treatment on surface properties of fabric sputtered with copper
Authors: Meng Lingling , Wei Qufu , Li Yueli , Xu Wenzheng
Published: February 2014

Purpose

– In this study, the polyester fabrics were treated with low temperature plasma before Cu sputtering. The effect of oxygen gas plasma pre-treatment on the surface structures, electrical properties, and mechanical properties of samples was investigated. The paper aims to discuss these issues.

Design/methodology/approach

– A laboratory direct current (DC) magnetron sputter coating system was used to deposit the nanoscale copper (Cu) films onto the surface of polyester plain fabric at room temperature.

Findings

– The crystal structure of the sputtered copper films did not show any obvious change on the O2-plasma-treated fabric, but the surface roughness and surface particle size increased significantly. Improvement in electrical properties of copper films was closely related to the deposition time. The tensile test results indicated that the mechanical properties of the plasma-treated polyester fabrics were also improved after copper coating.

Originality/value

– The research reports on the functional textiles, and the experiment results and analysis are original. There is a great potential to commercialize such functional textiles.
Automatic human body segmentation based on feature extraction
Authors: Jo JoonWoo , Suh MoonWon , Oh TaeHwan , Kim HeeSam , Bae HanJo , Choi SoonMo , Han SungSoo
Published: February 2014

Purpose

– Automatic segmentation of unorganized 3D human body scan data was developed without heuristic specified values. It was reliable in finding the upper body's primary landmarks. The paper aims to discuss these issues.

Design/methodology/approach

– Quasi boundary point sequence (QBPS) was defined to find the boundary of the human body. Body scan data were categorized by clustering the features extracted from the predefined QBPS. A non-uniform rational B-spline (NURBS) approximation was used to detect the landmarks of the segmented upper torso.

Findings

– The segmentation method based on feature extraction was reliable regardless of the scan data's fidelity. It was verified that the landmark detection method introduced in this work is more robust than a previous method that utilizes the position of point data.

Originality/value

– There are several studies of human body segmentation and body landmark detection. This work, however, aims to automate fully segmentation and develop more reliable searching methods. Unlike previous work that uses only 2D human body information, this work uses 3D body information. Furthermore, previous landmark searching methods were superseded by more robust methods applying NURBS approximations.
Design for static stiffness of hydrostatic bearings: double-action variable compensation of spool-type restrictors
Authors: Kang Yuan , Yang Ding-Wen , Hu Sheng-Yan , Hung Yu-Hong , Peng De-Xing , Chen Shih-Kang
Published: February 2014

Purpose

– This paper is the third part of a serial studies for constant and variable compensations of the closed-type hydrostatic thrust bearings which has face-to-face recesses couple. The static stiffness of closed-type hydrostatic thrust bearings can then be obtained from the differentiation of recess pressure with respect to worktable displacement. The paper aims to discuss these issues.

Design/methodology/approach

– In this paper, the double-action restrictors of cylindrical-spool-type and tapered-spool-type are taken into consideration for variable compensation of hydrostatic bearings.

Findings

– The static stiffness in thrust direction of hydrostatic bearing is determined by the flow continuity equations that are formulated by film flow and compensation flow for each recess, respectively. The type selection and parameter determination of the double-action spool-type restrictors can be obtained from finding results of this study for maximum stiffness in design of hydrostatic bearings.

Originality/value

– This study reveals that the appropriate range of recess pressure ratio and design parameters of restrictors for the maximum stiffness can be obtained, the avoidance of negative stiffness is also provided.
Tribological properties of A356 Al-Si alloy composites under dry sliding conditions
Authors: Vencl Aleksandar , Bobic Ilija , Stojanovic Blaza
Published: February 2014

Purpose

– Aluminium alloys are frequently applied in automotive and other industries, since they provide mass reduction. Besides positive effects, aluminium alloys have their shortcomings reflected, first of all, in inappropriate tribological properties of these materials. The aim of this research was to enable the production of cheap aluminium alloy matrix composite with favourable combination of structural, mechanical and tribological properties, focusing on the tribological behaviour.

Design/methodology/approach

– The A356 Al-Si alloy was used as a matrix for producing metal matrix composites in compocasting process. Three different materials, in form of particles, were added to the matrix (Al2O3, SiC and graphite). Hardness and tribological properties (wear, friction and wear mechanism) of heat-treated (T6) samples were examined and compared. Tribological tests were carried out on ball-on-block tribometer under dry sliding conditions. Sliding was linear (reciprocating). Counter body was alumina ball. Average velocity was 0.038 m/s (max. 0.06 m/s), sliding distance was 500 m and normal load was 1 N.

Findings

– The effect of two different ceramic particles and graphite particles on tribological properties of obtained composites was evaluated. Wear resistance of composites reinforced with SiC particles was higher and coefficient of friction was lower compared to the composite reinforced with Al2O3 particles. A dual hybrid composite (with SiC and graphite particles) showed the lowest value of wear rate and friction coefficient. Dominant wear mechanism for all tested material was adhesion.

Research limitations/implications

– It seems useful to continue the work on developing hybrid composites containing soft graphite particles with A356 Al-Si alloy as matrix. The major task should be to improve particles distribution (especially with higher graphite content) and to explore tribological behaviour in diverse working conditions.

Originality/value

– Particulate composites with A356 aluminium alloy as a matrix produced in compocasting process using ceramic particles (Al2O3, SiC) were investigated in many researches, but there are only few detailed analyses of dual composites (with the addition of ceramic and graphite particles). In some previous studies, it was shown that compocasting process, as relatively cheap technology, can obtain good structural and mechanical characteristics of composites. In this study, it was shown that even a low graphite content, under specified conditions, can improve tribological properties.
The tribocorrosion behaviors of Hastelloy C276 alloy in seawater
Authors: Jun Chen , Fengyuan Yan , Jianzhang Wang
Published: February 2014

Purpose

– The aim of this work is to study the tribocorrosion behaviors of Hastelloy C276 alloy sliding against AISI 316 stainless steel in artificial seawater and distilled water.

Design/methodology/approach

– The electrochemical behaviors of Hastelloy C276 alloy are measured by potentiodynamic polarization method. The tribocorrosion properties are evaluated using an MRH-03 type ring-on-block test rig in artificial seawater with different salinity. The wear loss is determined by the difference of sample weight before and after tribocorrosion tests.

Findings

– The results show that the typical passivation behavior is observed for C276 alloy in seawater. The Hastelloy C276 alloy has the maximum corrosion current density in 3 percent seawater, which is the synergism of salt concentration and dissolved oxygen in seawater. Friction coefficients are in general larger in distilled water compared with seawater. The wear loss in seawater is always higher than that in distilled water for both alloys. Seawater could reduce the friction coefficient and the wear resistance.

Originality/value

– Many scientists focused on studying the friction behavior of passive metals sliding against alumina or zirconia, which was considered to act as inert antagonist in the experiments. However, there are few papers available on the tribocorrosion properties of passive metals sliding each other in corrosion mediums.
Simulation and optimization of thrust circular bearings with planes sector-shaped
Authors: J.C. Blanco Claudio , T. Prata Alvaro , C.L. Pessoa Francisco
Published: February 2014

Purpose

– The purpose of this paper is to analyze journal thrust bearings geometries, used in household refrigerators, using a modified version of the Reynolds equation which includes the inertial terms.

Design/methodology/approach

– The Reynolds equation was solved through the finite volume method, thus providing the pressure field in the lubricant film and, consequently, the load and the power used by the bearing. Such parameters depend on bearing geometry, which was optimized through the method of Lagrange multipliers, to support a given load and use the lowest power possible. The optimized geometries included the Rayleigh pad with 4, 8 and 16 steps, and a milled geometry with 4 steps.

Findings

– For the Rayleigh pad, the number of steps was varied and a decrease in the power consumed with the increase in the number of steps was observed. The milled pad performance was better than that Rayleigh pad with 4 steps and comparable to the pad with 8 steps.

Originality/value

– The manufacture of pads, with a high number of steps, is complicated and, then, a milled pad with 4 steps was proposed in this paper. The use of milled pads is a technological innovation worthy of a more thorough investigation, considering its facility of manufacture when compared to the Rayleigh pad.
A comparison of two minimum quantity lubrication delivery systems
Authors: Kurgin Sheri , M. Dasch Jean , L. Simon Daniel , C. Barber Gary , Zou Qian
Published: February 2014

Purpose

– The purpose of this paper is to compare the performance of single- and dual-channel minimum quantity lubrication (MQL) for reaming spool bores in an automotive transmission valve body.

Design/methodology/approach

– Machining experiments are conducted under various parameters for both single- and dual-channel MQL. Comparison metrics include part surface temperature, spindle power consumption and hole quality. Experimental data from traditional through-tool flood coolant are provided as a baseline for spindle power consumption and part quality.

Findings

– The results show that with proper tooling and machining parameters, dual-channel MQL can perform equivalently or better than flood coolant. Single-channel MQL was not deemed suitable for this machining application.

Practical implications

– The results of the study show that MQL can be successfully applied for precision reaming of aluminum and can provide guidance in developing an MQL system.

Originality/value

– Few studies have been performed for reaming holes in general, and very few studies have been performed for reaming with MQL. Reaming is a critical operation used to create holes with precise quality. No study was found in the literature review that directly compared the performance of single- and dual-channel MQL delivery systems.
Running-in of repaired engines using friction modifiers
Authors: S. Dimitrov Mitko , I. Nikolov Mitko , N. Gospodinova Nina , J. Pavlov Dimitar
Published: February 2014

Purpose

– The paper aims to present a new friction modifier (mixture of zinc and copper oleates) proper for industrial running-in of repaired engines.

Design/methodology/approach

– The method of comparison was used for testing the offered friction modifier, a market product “Renom Engine” and a blank sample of motor oil as an etalon. Running-in time has been established. The mechanical losses change and the relevant coefficients have been determined. Data of the bearings wear have been included.

Findings

– The benefit of the metal oleates and Renom Engine usage as friction modifiers has been proved. Time for industrial cold running-in of repaired engines decreases by around 20 per cent when friction modifiers are used in comparison with the etalon oil. The coefficient of the mechanical losses reduction at running-in with friction modifiers is higher than the coefficient for the etalon oil. The higher coefficient values indicate that the running-in of the working surfaces occurs more intensively and for a shorter period of time. Lower wear of the bearings is combined with smaller roughness of the friction surface, which secures higher quality of the surfaces run-in with the friction modifiers and greater capacity by around 30 per cent.

Originality/value

– This study introduces a new friction modifier for industrial running-in of repaired engines. It would be of interest to the customers and manufacturers of oil additives.
Wear performance and its online monitoring of the semimetal brake lining for automobiles
Authors: Yin Yan , Bao Jiusheng , Yang Lei
Published: February 2014

Purpose

– In order to improving the braking reliability and assuring the driving safety of automobiles, this paper aims at the wear performance and its online monitoring of its brake lining.

Design/methodology/approach

– The wear performance of the semimetal brake lining for automobiles was investigated on a self-made braking tester for disc brakes. Based on the experimental data, an intelligent forecasting model for the wear rate was established by the artificial neural network (ANN) technology. And by taking it as a core, an online braking wear monitoring system for automobiles was designed.

Findings

– It is shown that the wear rate rises obviously with the increasing of both initial braking velocity and braking pressure. By the contrast, the initial braking velocity affects the wear rate more seriously. The ANN model trained by the experimental data shows favorable capability for predicting of the wear rate. The big forecasting errors at high velocity and heavy load should be attributed to the jumping of the wear rate at this period. Based on the existed sensors and electronic control unit system of automobiles, the online braking wear monitoring system can be established easily by the ANN technology.

Originality/value

– A self-made braking tester for disc brakes was used to test the wear performance, which can simulate better the actual disc braking conditions than the standard pin-on-disc friction tester. An online braking wear monitoring system was designed to help improving the braking reliability and safety of automobiles.
Anti-friction property of surface patterning nano-hard film on the monocrystalline silicon surface
Authors: Wengang Chen , Shirong Ge , Lianyun Pang , Yonghai Zhang
Published: February 2014

Purpose

– Three types of pattern on the monocrystalline silicon surface were prepared by using laser surface processing equipment. The DLC film and Si-DLC film on the patterning surface were deposited by using PECVD-2D plasma chemical vapor deposition sets. The paper aims to discuss these issues.

Design/methodology/approach

– The tribological properties of the films were investigated by using the UMT-2 micro friction and wear tester. The surface topography, composition, hardness and elastic modular of the films were determined by Raman spectrum, nano mechanics tester and three-dimensional topography instrument. The worn surface topographies of the surface patterning films were tested by scanning electron microscopy.

Findings

– The results show that the patterning monocrystalline silicon substrate surface has good anti-friction property under low load. The patterning DLC film and Si-DLC film surface have very good anti-friction property under all the test loads. The reason of these results is that the surface patterning film not only reduces the real contact area of the friction pairs but also has low surface bonding force.

Originality/value

– This paper prepared three kinds of microscopic patterns on the monocrystalline silicon surface by using laser surface processing equipment. And then deposited DLC film and Si-DLC film on the patterning surface. All kinds of surface patterning monocrystalline silicon had very good anti-friction property under low load. And all kinds of surface patterning nano-hard film had perfect anti-friction property under all test loads.