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Article
Publication date: 19 September 2019

Wenchao Wu, Hsiaoping Chien, Takeshi Sakurai and Satoru Muranaka

The purpose of this paper is to examine the asymmetry of vertical price transmission (i.e. from the wholesale to the retail market) in the Nigerian cowpea market and identify its…

166

Abstract

Purpose

The purpose of this paper is to examine the asymmetry of vertical price transmission (i.e. from the wholesale to the retail market) in the Nigerian cowpea market and identify its causes.

Design/methodology/approach

The authors surveyed 19 markets in Kano and Ibadan from 2012 to 2015. The autoregressive distributed lag model and asymmetric error correction model were adopted to test the asymmetry of vertical price transmission.

Findings

Results suggest that price transmission in Kano is symmetric, but it is asymmetric in Ibadan. This distinction is caused by the differences in the market structure (in terms of competition level, inventory period and transaction cost) of these cities.

Originality/value

This is the first study to empirically investigate the vertical price transmission in two Nigerian cowpea markets. It is also the first to reveal the role of the market structure in price transmission through a comparison of two markets. The findings provide policy implications and will help create a more efficient food market in Nigeria.

Details

British Food Journal, vol. 121 no. 11
Type: Research Article
ISSN: 0007-070X

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Article
Publication date: 17 May 2024

Wenchao Zhang, Enming Cui, Cheng Wang, Baoquan Zhang, Jiwei Jin, Pengfei Zhang, Wending Wu and Mingwei Wang

An investigation was conducted into the impact of various process parameters on the surface and subsurface quality of glass-ceramic materials, as well as the mechanism of material…

93

Abstract

Purpose

An investigation was conducted into the impact of various process parameters on the surface and subsurface quality of glass-ceramic materials, as well as the mechanism of material removal and crack formation, through the use of ultrasonic-assisted grinding.

Design/methodology/approach

A mathematical model of crack propagation in ultrasonic-assisted grinding was established, and the mechanism of crack formation was described through the model. A series of simulations and experiments were conducted to investigate the impact of process parameters on crack depth, surface roughness, and surface topography during ultrasonic-assisted surface and axial grinding. Additionally, the mechanism of crack formation was explored.

Findings

During ultrasonic-assisted grinding, the average grinding forces are between 0.4–1.0 N, which is much smaller than that of ordinary grinding (1.0–3.5 N). In surface grinding, the maximum surface stresses between the workpiece and the tool gradually decrease with the tool speed. The surface stresses of the workpiece increase with the grinding depth, and the depth of subsurface cracks increases with the grinding depth. With the increase of the axial grinding speed, the subsurface damage depth increases. The roughness increases from 0.780um/1.433um.

Originality/value

A mathematical model of crack propagation in ultrasonic-assisted grinding was established, and the mechanism of crack formation was described through the model. The deformation involved in the grinding process is large, and the FEM-SPH modeling method is used to solve the problem that the results of the traditional finite element method are not convergent and the calculation efficiency is low.

Details

Multidiscipline Modeling in Materials and Structures, vol. 20 no. 4
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 7 January 2021

Pei Li, Ye Tian, JunJie Wu and Wenchao Xu

The purpose of this paper evaluates the effects of the Great Western Development (GWD) policy on agricultural intensification, land use, agricultural production and rural poverty…

616

Abstract

Purpose

The purpose of this paper evaluates the effects of the Great Western Development (GWD) policy on agricultural intensification, land use, agricultural production and rural poverty in western China.

Design/methodology/approach

The authors collect county-level data on land use, input application, grain crop production, income, poverty and geophysical characteristics for 1996–2005 and use a quasi-natural experimental design of difference-in-differences (DD) in the empirical analysis.

Findings

Results suggest that the GWD policy significantly increased the grain crop production in western China. This increase resulted from higher yield, with increased fertilizer use and agricultural electricity consumption per hectare, and more land allocated to grow grain crops. The policy also increased land-use concentration, reduced crop diversity and alleviated rural poverty in western China.

Originality/value

This paper makes three contributions. First, the authors add to the growing literature on the GWD policy by evaluating its effects on farm household decisions and exploring the mechanisms and broad socioeconomic impacts in western China. Second, the authors take advantage of a quasi-natural experimental design to improve the identification strategy where input use, land allocation, production and off-farm labor participation are all endogenous in a farm household. Third, the authors explore a long list of variables within one integrated dataset to present a comprehensive picture of the impact of the GWD policy.

Details

China Agricultural Economic Review, vol. 13 no. 2
Type: Research Article
ISSN: 1756-137X

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Article
Publication date: 2 January 2018

Yongkun Wang, Tianran Ma, Wenchao Tian, Junjue Ye, Xing Wang and Xiangjun Jiang

The purpose of this paper is to prepare novel electroactive shape memory nanocomposites based on graphene and study the thermomechanical property and shape memory behavior of…

293

Abstract

Purpose

The purpose of this paper is to prepare novel electroactive shape memory nanocomposites based on graphene and study the thermomechanical property and shape memory behavior of nanocomposites.

Design/methodology/approach

Graphene was dispersed in N,N-dimethylformamide, and the mixture was spooned into epoxy-cyanate ester mixtures to form graphene/epoxy-cyanate ester nanocomposites. The nanocomposites were deformed under 150°C, and shape recovery test was conducted under an electric voltage of 20-100 V.

Findings

Graphene is used to improve the shape recovery behavior and performance of shape-memory polymers (SMPs) for enhanced electrical actuation effectiveness. With increment of graphene content, the shape recovery speed of nanocomposites increases significantly.

Research limitations/implications

A simple way for fabricating electro-activated SMP nanocomposites has been developed by using graphene.

Originality/value

The outcome of this study will help to fabricate the SMP nanocomposites with high electrical actuation effectiveness and improve the shape recovery speed of the nanocomposites.

Details

Pigment & Resin Technology, vol. 47 no. 1
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 14 November 2024

Yan Wang, Chunpeng Liu and Wenchao Zhao

This study employed a questionnaire survey to understand the safety attitudes, focusing on safety motivation and risk tolerance as well as safety management practices, including…

23

Abstract

Purpose

This study employed a questionnaire survey to understand the safety attitudes, focusing on safety motivation and risk tolerance as well as safety management practices, including safety training and safety incentives, among construction site employees, including both managerial personnel and frontline workers. The objective was to explore the relationship between safety management practices and safety attitudes within both the managerial and frontline worker groups.

Design/methodology/approach

This study was conducted among 1,026 construction workers and 256 managerial personnel at 53 construction sites across 12 provinces in China. A t-test was used to compare the differences in safety-related scores between managerial personnel and frontline workers, and a structural equation model was used to explore the relationship between safety attitudes and safety management.

Findings

This study found that the scores of managerial personnel for safety motivation, safety training and safety incentives were significantly higher than construction workers, while their scores for risk tolerance were significantly lower than construction workers. Managerial personnel’s safety motivation has a significant positive impact on both safety training and safety incentives, while their risk tolerance has a significant negative impact on safety incentives. Safety training has a significant positive effect on construction workers’ safety motivation, whereas safety incentives have a significant negative impact on construction workers’ risk tolerance.

Originality/value

This study is one of the few that have investigated construction safety by conducting surveys targeting both site managerial personnel and frontline workers, employing an empirical approach to validate the role of safety management in transmitting safety attitudes from site managerial personnel to frontline workers.

Details

Engineering, Construction and Architectural Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0969-9988

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Article
Publication date: 21 September 2022

Yujie Zhang, Wenchao Niu and Bin Li

Structural stress and strain in the key components of aircraft structure is important for structural health monitoring and strength assessment. However, the measure of dynamic…

107

Abstract

Purpose

Structural stress and strain in the key components of aircraft structure is important for structural health monitoring and strength assessment. However, the measure of dynamic strain is often difficult to implement because of the complex test equipment and inconvenient measure points, especially in flight test. This study aims to propose an algorithm of dynamic strain estimation using the acceleration response in time domain to simplify the measure of dynamic strain.

Design/methodology/approach

The relationship between the strain and acceleration response is established through the sinusoidal response or modal analysis, which is insensitive to the excitation position and form. A band-pass filter is used to obtain the modal acceleration response, and a filter frequency band selection method is proposed. Then, the dynamic strain at the concerned points can be estimated based on the modal superposition principle.

Findings

Simulation and experiment are implemented to validate the applicability and effectiveness of the strain estimation method. The estimated strain results agree well with numerical simulation as well as the experimental results. The simplicity and accuracy of the strain estimation method show practicability for dynamic strength and fatigue analysis in engineering applications.

Originality/value

An algorithm of dynamic strain estimation using the acceleration response in time domain is developed. A band-pass filter is used to obtain the modal acceleration response, and a filter frequency band selection method is proposed. The dynamic strain at the concerned points can be estimated based on the modal superposition principle.

Details

Aircraft Engineering and Aerospace Technology, vol. 95 no. 4
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 24 April 2023

Wenchao Duan, Yiqiang Yang, Wenhong Liu, Zhiqiang Zhang and Jianzhong Cui

The purpose of this paper is to reveal the solute segregation behavior in the molten and solidified regions during direct chill (DC) casting of a large-size magnesium alloy slab…

246

Abstract

Purpose

The purpose of this paper is to reveal the solute segregation behavior in the molten and solidified regions during direct chill (DC) casting of a large-size magnesium alloy slab under no magnetic field (NMF), harmonic magnetic field (HMF), pulsed magnetic field (PMF) and two types of out-of-phase pulsed magnetic field (OPMF).

Design/methodology/approach

A 3-D multiphysical coupling mathematical model is used to evaluate the corresponding physical fields. The coupling issue is addressed using the method of separating step and result inheritance.

Findings

The results suggest that the solute deficiency tends to occur in the central part, while the solute-enriched area appears near the fillet in the molten and solidified regions. Applying magnetic field could greatly homogenize the solute field in the two-phase region. The variance of relative segregation level in the solidified cross-section under NMF is 38.1%, while it is 21.9%, 18.6%, 16.4% and 12.4% under OPMF2 (the current phase in the upper coil is ahead of the lower coil), HMF, PMF and OPMF1 (the current phase in the upper coil lags behind the lower coil), respectively, indicating that OPMF1 is more effective to reduce the macrosegregation level.

Originality/value

There are few reports on the solute segregation degree in rectangle slab under magnetic field, especially for magnesium alloy slab. This paper can act a reference to make clear the solute transport behavior and help reduce the macrosegregation level during DC casting.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 33 no. 7
Type: Research Article
ISSN: 0961-5539

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Book part
Publication date: 13 September 2018

Wenchao Ma, Lina He, Zeng Dan, Guanyi Chen and Xuebin Lu

With the rapid development of China’s urbanisation and market economy, municipal solid waste (MSW) generation is increasing dramatically. In response to the threat of…

Abstract

With the rapid development of China’s urbanisation and market economy, municipal solid waste (MSW) generation is increasing dramatically. In response to the threat of environmental pollution and the potential value of converting waste into energy, both the government and the public are now paying more attention to MSW treatment and disposal methods. In 2014, 178.6 million tonnes of MSW was collected at a safe treatment rate of 84.8%. However, the treatment methods and the composition of MSW are influenced by the collection area, its gross domestic product, population, rainfall and living conditions. This chapter analysed the MSW composition properties of Lhasa, Tibet, compared with other cities, such as Beijing, Guangzhou and so forth. The research showed that the moisture content of MSW in Lhasa approaches 31%, which is much lower than the other cities mentioned previously. The proportion of paper and plastics (rubbers) collected was 25.67% and 19.1%, respectively. This was 1.00–3.17 times and 0.75–2.44 times more than those found in Beijing and Guangzhou, respectively. Non-combustibles can reach up to 22.5%, which was 4.03–9.11 times that of Beijing and Guangzhou, respectively. The net heating values could reach up to 6,616 kilojoule/kilogram. The food residue was only half the proportion found in other cities. Moreover, the disposal method applied in each city has also been studied and compared.

Details

Unmaking Waste in Production and Consumption: Towards the Circular Economy
Type: Book
ISBN: 978-1-78714-620-4

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Article
Publication date: 1 March 1989

Wenchao Zhang and K.E. Evans

In the design of anisotropic materials, such as advanced fibre‐reinforced composites, the failure envelope has a crucial role. A geometrical representation of the envelope is of…

53

Abstract

In the design of anisotropic materials, such as advanced fibre‐reinforced composites, the failure envelope has a crucial role. A geometrical representation of the envelope is of particular value to investigate the highly anisotropic nature of the strength of the material. This provides the design engineer with a visualization of the failure envelope by graphically representing it using a CAD package. Use is made of both stress‐based and strain‐based polynomial failure criteria and examples are given of changes in the failure envelope due to changes in fibre orientation for a high strength graphite/epoxy composite lamina.

Details

Engineering Computations, vol. 6 no. 3
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 11 October 2021

Wenchao Xi, Boxue Song, Jinlong Dong, Tianqi Zhang, Tianbiao Yu and Jun Wang

Laser cladding has been used in the field of repairing damaged parts of machine tools due to its advantages of less processing restrictions and easy formation of a good…

123

Abstract

Purpose

Laser cladding has been used in the field of repairing damaged parts of machine tools due to its advantages of less processing restrictions and easy formation of a good metallurgical bond with the base material. However, the mechanical properties of the coating sometimes cannot meet the process requirements. Therefore, the purpose of this paper is to prepare coatings with high microhardness and flexural strength.

Design/methodology/approach

The YCF102 alloy powder was mixed with different contents of Co and tested for laser cladding on AISI 1045 substrate under the same process parameters. The main phase composition of the coating was revealed by the XRD results. The main chemical composition of the coating was determined by the SEM and EDS results. In addition, the effect of Co content on the microstructure, microhardness and flexural strength of the coatings was investigated.

Findings

The results show that when the Co content is 2 wt% and 4 wt%, Co does not form compounds with other elements, but is uniformly distributed in the coating. And when the Co content is 6 wt% and 8 wt%, the Co reacts with Fe in the coating and generates Co3Fe7 in situ. The increase in Co did not result in a monotonic change in microhardness, but significantly improved the flexural strength and the flatness of the microstructure of the coating. When the Co content of the mixed powder is 8 wt%, the coating has high microhardness and flexural strength.

Originality/value

Co/YCF102 composite coating with high microhardness and flexural strength was prepared. This paper provides a theoretical and practical basis for research in the area of repairing damaged parts of machine tools by laser cladding.

Details

Rapid Prototyping Journal, vol. 28 no. 4
Type: Research Article
ISSN: 1355-2546

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