bluuebunny/crossref_metadata_2025 huggingface dataset:
MTAG: Multi-Trait Analysis of GWAS
Authors: Turley Patrick , Walters Raymond K. , Maghzian Omeed , Okbay Aysu , Lee James J. , Fontana Mark Alan , Nguyen-Viet Tuan Anh , Wedow Robbee , Zacher Meghan , Furlotte Nicholas A. ,   23andMe Research Team,   Social Science Genetic Association Consortium, Magnusson Patrik , Oskarsson Sven , Johannesson Magnus , Visscher Peter M. , Laibson David , Cesarini David , Neale Benjamin M. , Benjamin Daniel J.
Published: March 2017

We introduce Multi-Trait Analysis of GWAS (MTAG), a method for joint analysis of summary statistics from GWASs of different traits, possibly from overlapping samples. We apply MTAG to summary statistics for depressive symptoms (Neff= 354,862), neuroticism (N= 168,105), and subjective well-being (N= 388,538). Compared to 32, 9, and 13 genome-wide significant loci in the single-trait GWASs (most of which are themselves novel), MTAG increases the number of loci to 64, 37, and 49, respectively. Moreover, association statistics from MTAG yield more informative bioinformatics analyses and increase variance explained by polygenic scores by approximately 25%, matching theoretical expectations.
Pan-cancer analysis distinguishes transcriptional changes of aneuploidy from proliferation
Authors: Buccitelli Christopher , Salgueiro Lorena , Rowald Konstantina , Sotillo Rocio , Mardin Balca R. , Korbel Jan O.
Published: March 2017

Patterns of gene expression in tumors can arise as a consequence of or result in genomic instability, characterized by the accumulation of somatic copy number alterations (SCNAs) and point mutations (PMs). Expression signatures have been widely used as markers for genomic instability, and both SCNAs and PMs could be thought to associate with distinct signatures given their different formation mechanisms. Here we test this notion by systematically investigating SCNA, PM, and transcriptome data from 2660 cancer patients representing 11 tumor types. Notably, our data indicate that similar expression signatures can be derived from correlating gene expression with either SCNA or PM load. Gene sets related to cell growth and proliferation generally associated positively, and immunoregulatory gene sets negatively, with variant burden. In-depth analyses revealed several genes whose de-regulation correlates with SCNA but not with PM burden, yielding downstream effectors of TP53 and MYC signaling unique to high-SCNA tumors. We compared our findings to expression changes observed in two different cancer mouse models with persistent mitotic chromosomal instability, observing a decrease in proliferative expression signatures. Our results suggest that overexpression of cell-cycle–related genes are a characteristic of proliferation, and likely tumor evolution, rather than ongoing genomic instability.
HINGE: long-read assembly achieves optimal repeat resolution
Authors: Kamath Govinda M. , Shomorony Ilan , Xia Fei , Courtade Thomas A. , Tse David N.
Published: March 2017

Long-read sequencing technologies have the potential to produce gold-standard de novo genome assemblies, but fully exploiting error-prone reads to resolve repeats remains a challenge. Aggressive approaches to repeat resolution often produce misassemblies, and conservative approaches lead to unnecessary fragmentation. We present HINGE, an assembler that seeks to achieve optimal repeat resolution by distinguishing repeats that can be resolved given the data from those that cannot. This is accomplished by adding “hinges” to reads for constructing an overlap graph where only unresolvable repeats are merged. As a result, HINGE combines the error resilience of overlap-based assemblers with repeat-resolution capabilities of de Bruijn graph assemblers. HINGE was evaluated on the long-read bacterial data sets from the NCTC project. HINGE produces more finished assemblies than Miniasm and the manual pipeline of NCTC based on the HGAP assembler and Circlator. HINGE also allows us to identify 40 data sets where unresolvable repeats prevent the reliable construction of a unique finished assembly. In these cases, HINGE outputs a visually interpretable assembly graph that encodes all possible finished assemblies consistent with the reads, while other approaches such as the NCTC pipeline and FALCON either fragment the assembly or resolve the ambiguity arbitrarily.
Hard X-ray-induced damage on carbon–binder matrix for in situ synchrotron transmission X-ray microscopy tomography of Li-ion batteries
Authors: Lim Cheolwoong , Kang Huixiao , De Andrade Vincent , De Carlo Francesco , Zhu Likun
Published: March 2017

The electrode of Li-ion batteries is required to be chemically and mechanically stable in the electrolyte environment for in situ monitoring by transmission X-ray microscopy (TXM). Evidence has shown that continuous irradiation has an impact on the microstructure and the electrochemical performance of the electrode. To identify the root cause of the radiation damage, a wire-shaped electrode is soaked in an electrolyte in a quartz capillary and monitored using TXM under hard X-ray illumination. The results show that expansion of the carbon–binder matrix by the accumulated X-ray dose is the key factor of radiation damage. For in situ TXM tomography, intermittent X-ray exposure during image capturing can be used to avoid the morphology change caused by radiation damage on the carbon–binder matrix.
Li9Al4Sn5as a new ordered superstructure of the Li13Sn5type
Authors: Pavlyuk Volodymyr , Dmytriv Grygoriy , Tarasiuk Ivan , Ehrenberg Helmut
Published: March 2017

Alloys from the ternary Li–Al–Sn system have been investigated with respect to possible applications as negative electrode materials in Li-ion batteries. This led to the discovery of a new ternary compound, a superstructure of the Li13Sn5binary compound. The ternary stannide, Li9Al4Sn5(nonalithium tetraaluminium pentastannide; trigonal,P\overline{3}m1,hP18), crystallizes as a new structure type, which is an ordered variant of the binary Li13Sn5structure type. One Li and one Sn site have \overline{3}m. symmetry, and all other atoms occupy sites of 3m. symmetry. The polyhedra around all types of atoms are rhombic dodecahedra. The electronic structure was calculated by the tight-binding linear muffin-tin orbital atomic spheres approximation method. The electron concentration is higher around the Sn and Al atoms, which form an [Al4Sn5]m−polyanion.
The silver(I) nitrate complex of the ligandN-(pyridin-2-ylmethyl)pyrazine-2-carboxamide: a metal–organic framework (MOF) structure
Authors: Cati Dilovan S. , Stoeckli-Evans Helen
Published: March 2017

The reaction of silver(I) nitrate with the mono-substituted pyrazine carboxamide ligand,N-(pyridin-2-ylmethyl)pyrazine-2-carboxamide (L), led to the formation of the title compound with a metal–organic framework (MOF) structure, [Ag(C11H10N4O)(NO3)]n, poly[μ-nitrato-[μ-N-(pyridin-2-ylmethyl-κN)pyrazine-2-carboxamide-κN4]silver(I)]. The silver(I) atom is coordinated by a pyrazine N atom, a pyridine N atom, and two O atoms of two symmetry-related nitrate anions. It has a fourfold N2O2coordination sphere, which can be described as distorted trigonal–pyramidal. The ligands are bridged by the silver atoms forming–Ag–L–Ag–L–zigzag chains along thea-axis direction. The chains are arranged in pairs related by a twofold screw axis. They are linkedviathe nitrate anions, which bridge the silver(I) atoms in a μ2fashion, forming the MOF structure. Within the framework there are N—H...O and C—H...O hydrogen bonds present.
Crystal structure of 4,4′-dinitro-[1,1′-biphenyl]-2-amine
Authors: Faizi Md. Serajul Haque , Haque Ashanul , Dege Necmi , Hasan Syed Imran , Dege Mustafa , Kalibabchuk Valentina A.
Published: March 2017

In the title biphenyl derivative, C12H9N3O4, the dihedral angle between the benzene rings is 52.84 (10)°. The nitro group attached to the benzene ring is inclined to the ring by 4.03 (2)°, while the nitro group attached to the amino-substituted benzene ring is inclined to the ring by 8.84 (2)°. In the crystal, molecules are linked by two pairs of N—H...O hydrogen bonds, forming chains propagating along [101]. Within the chains, these N—H...O hydrogen bonds result in the formation ofR22(20) andR22(14) ring motifs. The latter ring motif is reinforced by a pair of C—H...O hydrogen bonds, enclosingR21(6) ring motifs. The chains are linked by a second C—H...O hydrogen bond, forming a three-dimensional supramolecular structure.
2-Amino-3-methylpyridinium hydrogen phthalate
Authors: Sivakumar P. , Anzline C. , Sudhahar S. , Israel S. , Chakkaravarthi G.
Published: March 2017

In the title molecular salt, C6H9N2
+·C8H5O4
−, the cation is protonated at the pyridine N atom and the anion is deprotonated at the hydroxy O atom. The anion features an intramolecular O—H...O hydrogen bond with the H atom located almost in the middle of the two O atoms. The dihedral angle between the pyridine and benzene rings is 19.17 (12)°. The N—H...O hydrogen bonds generate R
2
2(8) and R
2
4(18) ring motifs. The crystal structure is stabilized by N—H...O hydrogen bonds. The structure is also influenced by weak π–π [centroid-to-centroid distance = 3.7347 (14) Å] interaction between the anions.
Towards a transformer transient model as a lumped-distributed parameter system
Authors: Zirka Sergey E. , Moroz Yuriy I. , Rahimpour Ebrahim
Published: March 2017

Purpose

The purpose of this study is to develop a topological model of a three-phase, three-limb transformer for low-frequency transients. The processes in the core limbs and yokes are reproduced individually by means of a dynamic hysteresis model (DHM). A method of accounting for the transformer tank with vertical magnetic shunts at the tank walls is proposed and tested on a 120 MVA power transformer.

Design/methodology/approach

The model proposed has been implemented independently in a dedicated Fortran program and in the graphical pre-processor ATPDraw to the ATP version of the electromagnetic transient program.

Findings

It was found that the loss prediction in a wide range of terminal voltages can only be achieved using a DHM with variable excess field component. The zero sequence properties of the transformer can be accurately reproduced by a duality-derived model with Cauer circuits representing tank wall sections (belts).

Research limitations/implications

In its present form, the model proposed is suitable for low-frequency studies. Its usage in the case when transformer capacitances are involved should be studied additionally.

Practical/implications

The presented model can be used either as an independent tool or serve as a reference for subsequent simplifications.

Social/implications

The model proposed is aimed at meeting the needs of electrical engineering and ecology-minded customers.

Originality/value

Till date, there were no experimental data on zero-sequence behavior of three-phase, three-limb transformer with vertical magnetic shunts, so no verified transient model existed. The model proposed is probably the first that matched this behavior and reproduced measured no-load losses for a wide voltage range.
Infinite-time linear–quadratic optimal control of the BLDC motor exploiting a nonlinear finite element model
Authors: Bernat Jakub , Stepien Slawomir Jan , Stranz Artur , Superczynska Paulina
Published: March 2017

Purpose

This paper aims to present a nonlinear finite element model (FEM) of the Brushless DC (BLDC) motor and the application of the optimal linear–quadratic control-based method to determine the excitation voltage and current waveform considering the minimization of the energy injected to the input circuit and energy lost. The control problem is designed and analyzed using the feedback gain strategy for the infinite time horizon problem.

Design/methodology/approach

The method exploits the distributed parameters, nonlinear FEM of the device. First, dynamic equations of the BLDC motor are transformed into a suitable form that makes an ARE (algebraic Riccati equation)-based control technique applicable. Moreover, in the controller design, a Bryson scaling method is used to obtain desirable properties of the closed-loop system. The numerical techniques for solving ARE with the gradient damping factor are proposed and described. Results for applied control strategy are obtained by simulations and compared with measurement.

Findings

The proposed control technique can ensure optimal dynamic response, small steady-state error and energy saving. The effectiveness of the proposed control strategy is verified via numerical simulation and experiment.

Originality/value

The authors introduced an innovative approach to the well-known control methodology and settled their research in the newest literature coverage for this issue.
Computation of accurate solutions when using element-free Galerkin methods for solving structural problems
Authors: Joldes Grand Roman , Teakle Peter , Wittek Adam , Miller Karol
Published: March 2017

Purpose

This paper aims to investigate the application of adaptive integration in element-free Galerkin methods for solving problems in structural and solid mechanics to obtain accurate reference solutions.

Design/methodology/approach

An adaptive quadrature algorithm which allows user control over integration accuracy, previously developed for integrating boundary value problems, is adapted to elasticity problems. The algorithm allows the development of a convergence study procedure that takes into account both integration and discretisation errors. The convergence procedure is demonstrated using an elasticity problem which has an analytical solution and is then applied to accurately solve a soft-tissue extension problem involving large deformations.

Findings

The developed convergence procedure, based on the presented adaptive integration scheme, allows the computation of accurate reference solutions for challenging problems which do not have an analytical or finite element solution.

Originality/value

This paper investigates the application of adaptive quadrature to solid mechanics problems in engineering analysis using the element-free Galerkin method to obtain accurate reference solutions. The proposed convergence procedure allows the user to independently examine and control the contribution of integration and discretisation errors to the overall solution error. This allows the computation of reference solutions for very challenging problems which do not have an analytical or even a finite element solution (such as very large deformation problems).
Numerical comparison of some contact detection algorithms
Authors: Schiava D'Albano Guillermo Gonzalo , Lukas Tomas , Su Fang , Korakianitis Theodosios , Munjiza Ante
Published: March 2017

Purpose

Contact interaction and contact detection (CD) remain key components of any discontinua simulations. The methods of discontinua include combined finite-discrete element method (FDEM), discrete element method, molecular dynamics, etc. In recent years, a number of CD algorithms have been developed, such as Munjiza–Rougier (MR), Munjiza–Rougier–Schiava (MR-S), Munjiza-No Binary Search (NBS), Balanced Binary Tree Schiava (BBTS), 3D Discontinuous Deformation Analysis and many others. This work aims to conduct a numerical comparison of certain algorithms often used in FDEM for bodies of the same size. These include MR, MR-S, NBS and BBTS algorithms.

Design/methodology/approach

Computational simulations were used in this work.

Findings

In discrete element simulations where particles are introduced randomly or in which the relative position between particles is constantly changing, the MR and MR-S algorithms present an advantage in terms of CD times.

Originality/value

This paper presents a detailed comparison between CD algorithms. The comparisons are performed for problem cases with different lattices and distributions of particles in discrete element simulations. The comparison includes algorithms that have not been evaluated between them. Also, two new algorithms are presented in the paper, MR-S and BBTS.
Numerical solution of mixed convection in a lid-driven cavity with arc-shaped moving wall
Authors: Ismael Muneer A.
Published: March 2017

Purpose

This paper investigates a numerical treatment to steady mixed convection in a lid-driven square cavity with arc-shaped moving wall or lid. The horizontal walls are thermally insulated. The vertical left wall is kept isothermally at high temperature, while the right arc-shaped moving wall is kept isothermally at low temperature.

Design/methodology/approach

Finite difference method in Cartesian coordinates with the upwind scheme is used in numerical solution. The irregular curved boundary has been treated by invoking non-uniform mesh grid with the ability to generate boundary fitted nodes. Jensen’s formulas of Neumann’s boundary condition have derived for the non-uniform mesh grid. The arc-shaped moving wall is considered as a segment of a rotating cylinder; thus, the studied pertinent parameters are the rotational speed of the arc-shaped wall in both aiding and opposing directions ω = −1,000-1,000, the arc-wall radius Ro = 0.5099-1.534 which is governed by its center (X0, Y0) = (1.1, 0.5)-(2.45, 0.5) and the Rayleigh number Ra = 103 − 106.

Findings

The results have shown that for low Rayleigh numbers, the rotational speed enhances heat transfer irrespective to the direction of rotation, while for high Rayleigh numbers, the aiding anticlockwise rotation (negative ω) enhances the heat transfer, while the opposing clockwise rotation (positive ω) manifests a retardation effect on the heat transfer. For a motionless arc-wall, its radius is ineffective for aiding heat transfer, while for non-zero arc-shaped wall speed, the heat transfer is an increasing function of its radius.

Originality/value

The arc-shaped moving wall has never been investigated until now. Therefore, the originality of this paper is due to studying the mixed convection in a lid-driven cavity with moving arc-shaped wall and inspecting the effect of its curvature and rotational speed in both directions on the flow and thermal fields.
Profiling causative factors leading to construction project delays in the United Arab Emirates
Authors: Mpofu Bekithemba , Ochieng Edward Godfrey , Moobela Cletus , Pretorius Adriaan
Published: March 2017

Purpose

A voluminous amount of research has been conducted on project delay in the recent past; however, the persistence of the problem demands that a relentless quest for solutions is upheld. It can be argued that the problem is likely to be more pronounced in areas where development pressure is the highest. One such area is the United Arab Emirates (UAE) where the construction industry is said to have reached an unparalleled position in the last decade. The purpose of this paper is to identify the most significant causes of delays in the UAE construction industry.

Design/methodology/approach

A survey was conducted targeting three key types of stakeholders, namely clients, contractors and consultants. Validity and reliability were achieved by first assessing the plausibility of construction delay variables in UAE. The verification took place after the interpretation of quantitative data, this involved presenting the findings to the main participants. The validation took place after the verification process. Rigour was achieved by engaging participants previously engaged in UAE and focussing on verification and validation, this included responsiveness of the researchers during group discussions, methodological coherence, appropriate sampling frame and data analysis.

Findings

From the analysis, the study unveiled a number of important causes of construction delays in the UAE, ranging from unrealistic contract durations to poor labour productivity, with consultants and clients seemingly shouldering the bulk of the “blame game”. It was evident that all the three main stakeholders in a construction project (clients, consultants and contractors) need to change their existing practices in order to ensure timely delivery of projects. The research also confirms that delays are country specific and appear to be time related hence they should be viewed within the social, economic and cultural settings of the UAE.

Research limitations/implications

A major limitation of the current study was the use of a single approach to facilitate data collection.

Practical implications

It was evident that practitioners need to change their existing practices in order to ensure timely delivery of projects. Continuous coordination and relationship between practitioners are required through the project life cycle in order to solve problems and develop project performance.

Originality/value

As suggested in this study methods should be put in place to reduce long and bureaucratic processes within the client’s organisations, not only to fulfil the requirements of the contract but also to suite fast-track projects.
Implementing health promotion programs in the Australian construction industry
Authors: Loudoun Rebecca , Townsend Keith
Published: March 2017

Purpose

The purpose of this paper is to identify possible agents and levers to trigger the development and implementation of work place health promotion programs (WHPPs) in the Australian construction industry. Unlike most large workplaces and most high-risk workplaces, these programs are rarely found in the construction sector.

Design/methodology/approach

Qualitative interviews with 80 trades workers and site-based and off-site construction managers are used to reveal perceptions of the impact of WHPPs and ill-health and poor health behaviors on site activities with a view to identifying leverage points to introduce WHPPs in construction.

Findings

Unhealthy lifestyle behaviors are seen as impacting on sites in three main ways: productivity (broadly defined), safety and interpersonal relations. Results also reveal specific roles and levers for different actors in the supply chain and a clear desire for a collective, industry-based response to identified health problems.

Practical implications

High levels of chronic diseases in the construction industry means firms within the sector must make a concerted attempt to change patterns of behavior or face significant long-term health implications for their workforce. Reducing levels of health and longevity of the workforce, mean work performance, productivity and participation is likely to decline.

Originality/value

Although construction workers are recognized as one of the workforces at most risk for life limiting diseases such as Type 2 diabetes and cardiovascular disease, relatively little work has investigated health and well-being considerations for construction workers. This study contributes by investigating possible levers and agents to create healthier workplaces in construction.
Influence of initial trust on control from client perspective: construction industry in China
Authors: Jiang Weiping , Lu Yujie
Published: March 2017

Purpose

The purpose of this paper is to investigate the effects of initial trust on control in the construction projects from the perspective of the client. The results are a good resource in managing the relationship between trust and control in the construction industry in China, and formulating a good working relationship with contractors.

Design/methodology/approach

Using a set of questionnaire, data were collected from project managers of the clients, who are responsible for the overall project management and have face-to-face interaction with the contractors. The data were analyzed by structural equation modeling to identify the effects of initial trust on control for the contractors.

Findings

Trust is examined in the construction industry in China through calculative and relational trust. Their effects are examined on three modes of inter-organizational control: outcome control, behavior control and social control. The results show that the calculative trust has strong effects on outcome-based and behavior control, while the relational trust, on social control.

Research limitations/implications

First, the conclusion of this research is based on the construction industry in China. It may not be suitable for other industries or other countries. Second, there may be other factors that influence the relationship between trust and control, such as the characteristics of the client and organizational culture, which are not taken into consideration in this research.

Practical implications

The effects of initial trust on control have been testified in the study. For the client, it is wise to take suitable control measures to face with the contractors with the consideration of initial trust. The contractors would apply the rule in the relationship between initial trust and control, and set up good relationship with the client.

Originality/value

This research has certain originality and value in theory and practice. First, this research analyzes the relationship between trust and control in a dynamical way, which has innovative significance to some extent. Second, research on inter-organization supplies a new perspective about project control. Finally, this research would offer a perspective to improve the present situation of the construction industry in China. If the clients use the trust and control measures appropriately, the harmonious relation can be achieved and projects performance can be improved.
Ibrahim – the cassava starch processor
Authors: Ohu Eugene Agboifo
Published: March 2017

Subject area

AgriBusiness entrepreneurship

Study level/applicability

Post-graduate and executive education classes in agribusiness: MBA, Executive Education programmes for senior managers; entrepreneurial studies and workshops for SMEs.

Case overview

This case study is centred on Ibrahim, a businessman in Tanzania, who decided to start a business to process and sell cassava starch flour. Following a market survey, he realized that the demand for cassava starch surpassed the supply and planned to bridge this gap. To realize his business idea, he applied for and received a loan from an investment bank (Tanzania Investment bank), with which he bought processing machines and some acres of land for the cultivation of the crop. Unfortunately, he encountered a major setback because the sub-standard processing machine he bought stopped working after one week. He could neither repair his equipment nor buy new ones because the bank refused to extend his loan facility. Ibrahim was also having problems meeting a huge international and local demand for his cassava because of inadequate supply of cassava by local farmers.

Expected learning outcomes

This paper aims to understand the entire cassava value chain, which is made up of three major players: growers, processors and end-users; to understand the business case for opting to focus on one of the three areas, what arguments could be given for being a grower, a processor or an end-user; to understand that there are different types of end-user products: cassava starch flour, high-quality cassava flour, both of which can come from an intermediate product called “grates”; to understand the reason for the paradox, that there is (potentially) a high demand for cassava flour locally, and yet these end-users are not yet willing to patronize the local market because supply is low, and supply is low, not because farmers cannot produce more, but simply because they are not processing more – why is this?; to understand that the “processing” stage seem to be the rate-limiting-stage in the cassava starch production value chain – how can this process be improved?; to understand the case for aggregating local farmers into cooperatives to produce enough cassava roots to feed the need of industrial processors, and aggregators can also collect and pre-process into “grates” before selling to industrial processing companies; and to understand the importance of locating processing plants close to the farms.

Supplementary materials

Teaching notes are available for educators only. Please contact your library to gain login details or email support@emeraldinsight.com to request teaching notes.

Subject code

CSS 3: Entrepreneurship.
Effects of moving lid direction on mixed convection and entropy generation in a cubical cavity with longitudinal triangular fin insertion
Authors: Kolsi Lioua , Öztop Hakan F. , Abu-Hamdeh Nidal , Mohamad Naceur Borjini , Ben Assia Habib
Published: March 2017

Purpose

The main purpose of this work is to arrive at a three-dimensional (3D) numerical solution on mixed convection in a cubic cavity with a longitudinally located triangular fin in different sides.

Design/methodology/approach

The 3D governing equations are solved via finite volume technique by writing a code in FORTRAN platform. The governing parameters are chosen as Richardson number, 0.01 ≤ Ri ≤ 10 and thermal conductivity ratio 0.01 ≤ Rc ≤ 100 for fixed parameters of Pr = 0.7 and Re = 100. Two cases are considered for a lid-driven wall from left to right (V+) and right to left (V−).

Findings

It is observed that entropy generation due to heat transfer becomes dominant onto entropy generation because of fluid friction. The most important parameter is the direction of the moving lid, and lower values are obtained when the lid moves from right to left.

Originality

The main originality of this work is to arrive at a solution of a 3D problem of mixed convection and entropy generation for lid-driven cavity with conductive triangular fin attachments.
Natural convection of nanofluid inside a wavy cavity with a non-uniform heating
Authors: Sheremet Mikhail , Pop Ioan , Öztop Hakan F. , Abu-Hamdeh Nidal
Published: March 2017

Purpose

The main purpose of this numerical study is to study on entropy generation in natural convection of nanofluid in a wavy cavity using a single-phase nanofluid model.

Design/methodology/approach

The cavity is heated non-uniformly from the wavy wall and cooled from the right side while it is insulated from the horizontal walls. The physical domain of the problem is transformed into a rectangular geometry in the computational domain using an algebraic coordinate transformation by introducing new independent variables ξ and η. The governing dimensionless partial differential equations with corresponding initially and boundary conditions were numerically solved by the finite difference method of the second-order accuracy. The governing parameters are Rayleigh number (Ra = 1000-100000), Prandtl number (Pr = 6.82), solid volume fraction parameter of nanoparticles (φ = 0.0-0.05), aspect ratio parameter (A = 1), undulation number (κ = 1-3), wavy contraction ratio (b = 0.1-0.3) and dimensionless time (τ = 0-0.27).

Findings

It is found that the average Bejan number is an increasing function of nanoparticle volume fraction and a decreasing function of the Rayleigh number, undulation number and wavy contraction ratio. Also, an insertion of nanoparticles leads to an attenuation of convective flow and enhancement of heat transfer.

Originality

The originality of this work is to analyze the entropy generation in natural convection within a wavy nanofluid cavity using single-phase nanofluid model. The results would benefit scientists and engineers to become familiar with the flow behaviour of such nanofluids, and will be a way to predict the properties of this flow for the possibility of using nanofluids in advanced nuclear systems, in industrial sectors including transportation, power generation, chemical sectors, ventilation, air-conditioning, etc.
A simple analytical approach to a nonlinear equation arising in porous catalyst
Authors: He Chun-Hui
Published: March 2017

Purpose

Analytical methods are widely used in heat and fluid flow; the purpose of this paper is to couple Taylor series method and Bubbfil algorithm to solve nonlinear differential equations.

Design/methodology/approach

A series solution is obtained with some unknown constants, which can be determined by incorporating boundary conditions, and the constants are calculated by the Bubbfil algorithm.

Findings

This paper gives an analytical approach to a nonlinear equation arising in porous catalyst using Taylor series and Bubbfil algorithm, and a high accuracy can be achieved.

Research limitations/implications

The coupled method of Taylor series and Bubbfil algorithm is a powerful method for nonlinear differential equations.

Practical implications

The proposed technology can be used in various numerical methods.

Originality/value

A new analytical method is proposed based on Taylor series and Bubbfil algorithm, which is a development of Newton’s iteration method and an ancient Chinese algorithm. The solution process is simple and easy to follow.
Numerical investigation of double-diffusive mixed convection in horizontal annulus partially filled with a porous medium
Authors: Moderres Mourad , Abboudi Said , Ihdene Malika , Aberkane Sofiane , Ghezal Abderahmane
Published: March 2017

Purpose

Double-diffusive convection within a tri-dimensional in a horizontal annulus partially filled with a fluid-saturated porous medium is numerically investigated. The aim of this work is to understand the effects of a source of heat and solute on the fluid flow and heat and mass transfer rates.

Design/methodology/approach

In the formulation of the problem, the Darcy–Brinkman–Forchheimer model is adopted to the fluid flow in the porous annulus. The laminar flow regime is considered under steady state conditions. Moreover, the transport equation for continuity, momentum, energy and mass transfer are solved using the Patankar–Spalding technique.

Findings

Through this investigation, the predicted results for both average Nusselt and Sherwood numbers were correlated in terms of Lewis number, thermal Grashof number and buoyancy ration. A comparison was made with the published results and a good agreement was found.

Originality/value

The paper’s results are validated by favorable comparisons with previously published results. The results of the problem are presented in graphical forms and discussed. This paper aims to study the behavior of the flow structure and heat transfer and mass for different parameters.
Pore scale evaluation of thermal conduction anisotropy in granular porous media using Lattice Boltzmann method
Authors: Askari R. , Ikram M.F. , Hejazi S. H.
Published: March 2017

Purpose

Thermal conduction anisotropy, which is defined by the dependency of thermal conductivity on direction, is an important parameter in many engineering and research studies such as the design of nuclear waste depositional sites. In this context, the authors aim to investigate the effect of grain shape in thermal conduction anisotropy using pore scale modeling that utilizes real shapes of grains, pores and throats to characterize petrophysical properties of a porous medium.

Design/methodology/approach

The authors generalize the swelling circle approach to generate porous media composed of randomly arranged but regularly oriented elliptical grains at various grain ratios and porosities. Unlike previous studies that use fitting parameters to capture the effect of grain–grain thermal contact resistance, the authors apply roughness to grains’ surface. The authors utilize Lattice Boltzmann method to solve steady state heat conduction through medium.

Findings

Based on the results, when the temperature field is not parallel to either major or minor axes of grains, the overall heat flux vector makes a “deviation angle” with the temperature field. Deviation angle increases by augmenting the ratio of thermal conductivities of solid to fluid and the aspect ratios of grains. In addition, the authors show that porosity and surface roughness can considerably change the anisotropic properties of a porous medium whose grains are elliptical in shape.

Originality/value

The authors developed an algorithm for generation of non-circular-based porous medium with a novel approach to include grain surface roughness. In previous studies, the effect of grain contacts has been simulated using fitting parameters, whereas in this work, the authors impose the roughness based on the its fractal geometry.
A novel blast-mitigation concept for light tactical vehicles
Authors: Grujicic Mica , d’Entremont Brian , Snipes Jennifer , Ramaswami S.
Published: March 2017

Purpose

A new concept solution for improving blast survivability of the light tactical military vehicles is proposed and critically assessed using computational engineering methods and tools.

Design/methodology/approach

The solution is inspired by the principle of operation of the rocket-engine nozzles, in general and the so called “pulse detonation” rocket engines, in particular, and is an extension of the recently introduced so-called “blast chimney” concept (essentially a vertical channel connecting the bottom and the roof and passing through the cabin of a light tactical vehicle). Relative to the blast-chimney concept, the new solution offers benefits since it does not compromise the cabin space or the ability of the vehicle occupants to scout the environment and, is not expected to, degrade the vehicle’s structural durability/reliability. The proposed concept utilizes side vent channels attached to the V-shaped vehicle underbody whose geometry is optimized with respect to the attainment of the maximum downward thrust on the vehicle. In the course of the channel design optimization, analytical and computational analyses of supersonic flow (analogous to the one often used in the case of the pulse detonation engine) are employed.

Findings

The preliminary results obtained reveal the beneficial effects of the side channels in reducing the blast momentum, although the extent of these effects is quite small (2-4 per cent).

Originality/value

To the authors’ knowledge, the present work is the first exploration of the side-vent-channels concept for mitigating the effect of buried-mine explosion on a light tactical vehicle.
Flow and heat transfer of couple stress fluid in a vertical channel in the presence of heat source/sink
Authors: Umavathi Jawali , Prathap Kumar Jada , Pop Ioan , Shekar Murudappa
Published: March 2017

Purpose

The purpose of this paper is to consider the problem of fully developed laminar mixed convection flow of a couple stress fluid in a vertical channel with the third-kind boundary conditions in the presence or absence of heat source/sink effect.

Design/methodology/approach

Through proper choice of dimensionless variables, the governing equations are developed. These governing equations are solved analytically by the differential transform method and numerically by the Runge–Kutta shooting method. Analytical solutions for the velocity and temperature profiles for heat generation and absorption of the problem are reported.

Findings

The mass flow rate and Nusselt numbers at both the left and right channel walls on mixed convection parameter, Brinkman number, couple stress parameter and heat generation/absorption parameter for equal and unequal Biot numbers are presented. Favorable comparisons of special cases with previously published work are obtained. It is found that velocity, temperature, mass flow rate and Nusselt number decrease with couple stress parameter and increase with mixed convection parameter and Brinkman number.

Originality/value

The work done in this paper is not done earlier to the authors’ knowledge. This is the first paper in which the sixth-order differential equation is solved using the semi-numerical method, which is a differential method.
Educational leadership and im/migration: preparation, practice and policy – the Swedish case
Authors: Norberg Katarina
Published: March 2017

Purpose

Migration to Sweden dramatically increased in 2015 and challenged the reception system at all levels and societal institutions, one of which was the school. As a response to the lack of a comprehensive educational strategy for newly arrived students, new regulations were passed in January 2016, the purpose of which was to guarantee equity and equality in education for all students, irrespective of their background. The regulations make demands on local politicians and the school leaders to adjust the reception, organization and teaching to support the newly arrived students’ learning. The purpose of this paper is to explore school leadership practices in turbulent times.

Design/methodology/approach

The study is situated in the field of post-migration ecology, as newly arrived students move from pre-migration to transmigration to post-migration contexts, the latter for this paper’s interest, when they arrive to their new schools. Seven principals in a transit municipality for migrants were interviewed to obtain a picture of how they are prepared for diversity in leadership and how policy and practice coincide.

Findings

The study reveals how policy and practice coincide due to a lack of intercultural and bilingual competences among the staff. The principal’s responsibility for a school structure and culture that support newly arrived students’ learning raises new demands on how principals are trained for diversity.

Originality/value

The study is a contribution to the little-researched field concerning school leadership and newly arrived students which raises new demands regarding how principals are trained for diversity.
Leading schools with migrant children in Shanghai
Authors: Qian Haiyan , David Walker Allan
Published: March 2017

Purpose

The purpose of this paper is threefold: to sketch the current policy context that frames the education of migrant children in Shanghai; to explore the work lives of school leaders in the privately owned but government-supported schools; and to understand the socio-cultural and educational factors that shape the leadership practices in these schools.

Design/methodology/approach

This paper drew from publicly accessible policy papers and interview data with four principals leading migrant children’s schools in Shanghai.

Findings

Migrant children’s schools have received increasing policy recognition and attention. Principals of these schools have strived to adopt various leadership strategies to enhance the quality of education as received by migrant children. However, due to the institutional barriers such as hukou, multiple challenges continue to face migrant children and leaders leading migrant schools.

Originality/value

This is one of the first few papers that collected data from principals leading migrant children’s schools. The paper contributes to further understandings about leadership in high-needs school context and about education quality and equity in relation to programme for international student assessment success in Shanghai.
A previous trainee experience: does it matter for retention of young graduates?
Authors: Cesário Francisco , Chambel Maria José
Published: March 2017

Purpose

This paper aims to explore the extent to which participation in a previous graduate recruitment programme affects graduates’ organisational affective commitment and their desire to remain.

Design/methodology/approach

With the support of a Portuguese organisation that annually operates a trainee programme to attract the best graduates from top universities, a questionnaire with human resource management (HRM) practices, affective commitment and turnover intention scales was used, with data collected from 168 recent recruited graduates representing two groups: graduates with previous participation in the trainee programme and graduates non-trainees.

Findings

Despite the company’s expectation that graduate trainees would present higher levels of affective commitment and lower intentions to voluntarily leave than employees recruited by traditional procedures, thet-test results show no significant differences between groups. However, correlations for both groups show a significant positive association between perceived HRM practices and affective commitment and a negative relation with turnover intention. These results suggest that placing a high value on HR practices leads to reinforcement of employment relations and a decrease in the desire to voluntarily leave.

Practical implications

The findings suggest the need for organisations to rethink their recruitment strategies and raise an interesting question with regard to organisational strategy: is it useful or fair to create two groups of graduates within the same organisation, because we may be promoting the development of two micro-cultures?

Originality/value

The study with this specific group is needed because of an increased implementation of trainee programmes all over Europe as a means of attracting graduates. The literature is scarce, focusing only on trainees’ attitudes compared to those recruited through traditional procedures.
Do compositions of board and audit committee improve financial disclosures?
Authors: Haldar Arunima , Raithatha Mehul
Published: March 2017

Purpose

This paper aims to examine the impact of corporate governance practices on the level of financial disclosures made by the Indian firms. This assumes importance in the context of the role of financial disclosures in addressing the agency problem.

Design/methodology/approach

Financial disclosure score is computed by considering disclosures provided by the generally accepted accounting principles and is the dependent variable. The independent variable – corporate governance score – is an index comprising internal governance mechanisms. The authors empirically examine the impact of corporate governance practices on financial disclosure using multiple regression model for 200 large listed Indian firms.

Findings

The study suggests that quality of governance practices significantly improves financial disclosure practices of the firm. Particularly, the composition of the audit committee is effective in improving disclosures.

Practical implications

The finding has implications for policy makers and practitioners. It will help investors, lenders, and other stakeholders to assess firms’ financial disclosure quality. In addition, the findings, suggest the influence of governance practices on disclosure, might help in the formulation of appropriate policies about board structure and audit function. It is also a call to investors to emphasize on governance quality of the investing firms.

Originality/value

The study builds a case for an urgent intervention for improving the existing governance standards to advance the quality of financial disclosure in an emerging market context.
The impact of horizontal conflict on reducing vertical conflict in Japan’s retail organizations
Authors: Seo Eunji , Takashima Katsuyoshi
Published: March 2017

Purpose

The purpose of this study is to investigate the negative impact of horizontal conflict on vertical conflict in a triadic configuration, which is based on the supposition that buyers who experience horizontal conflict due to competition with other buyers are motivated to limit vertical conflict to better cooperate with store staff.

Design/methodology/approach

This study tests the hypotheses with an AMOS-based structure equation model based on survey data of 236 merchandise managers at Japanese retailers.

Findings

The study’s findings demonstrate that process conflict concerning resource and role allocation, negatively affects the task conflict and relationship conflict involved in vertical interactions. The results suggest that conflict between buyers is an accelerative mechanism affecting the construction of cooperative relationships between buyers and store staff.

Originality/value

Previous studies have discussed the possibility of positive effects arising from process conflict. In this study, the authors found that horizontal process conflict tolerates vertical conflict statistically and identified a new positive effect of process conflict.