Search results

Micro-texture is processed on the surface to reduce the friction of the contact surface, and its application is more and more extensive. The purpose of this paper is to create a texture function model to study the influence of surface parameters on the accuracy of the simulated surface so that it can more accurately reflect the characteristics of the real micro-textured surface.

The microstructure function model of rough surfaces is established based on fractal geometry and polar coordinate theory. The offset angle θ is introduced into the fractal geometry function to make the surface asperity normal perpendicular to the tangent of the surface. The 2D and 3D contour surfaces of the surface groove texture are analyzed by MATLAB simulation. The effects of fractal parameters (D and G) and texture parameter h on the curvature of the surface micro-texture model were studied.

This paper more accurately characterizes the textured 3D curved surface, especially the surface curvature. The scale coefficient G significantly affects curvature, and the influence of fractal dimension D and texture parameters on curvature can be ignored.

The micro-texture model of the rough surface was successfully established, and the range of fractal parameters was determined. It provides a new method for the study of surface micro-texture tribology.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2023-0298/

Manipulator motion accuracy is a fundamental requirement for precision manufacturing equipment. Light weight manipulators in high speed motions are vulnerable to deformations. The purpose of this work is to analyze the effect of link deformation on the motion precision of parallel manipulators.

The flexible dynamics model of the links is first established by applying the Euler–Bernoulli beam theory and the assumed modal method. The rigid-flexible coupling equations of the parallel mechanism are further derived by using the Lagrange multiplier approach. The elastic energy resulting from spiral motion and link deformations are computed and analyzed. Motion errors of the 3-link torque-prismatic-torque parallel manipulator are then evaluated based on its inverse kinematics. The validation experiments are also conducted to verify the numerical results.

The lateral deformation and axial deformation are largest at the middle of the driven links. The axial deformation at the middle of the driven link is approximately one-tenth of the transversal deformation. However, the elastic potential energy of the transversal deformation is much smaller than the elastic force generated from axial deformation.

Knowledge on the relationship between link deformation and motion precision is useful in the design of parallel manipulators for high performing dynamic responses.

This work establishes the relationship between motion precision and the amount of link deformation in parallel manipulators.

This paper aims to propose a novel blockchain crowdfunding projects evaluation approach using extended techniques for order preferences by similarity to ideal solution (TOPSIS) under fuzzy environment.

By analyzing the characteristics and operation process of blockchain crowdfunding model, this paper formulates the evaluation index system from three dimensions of human resources, capital and publicity. In addition, the entropy method is used to calculate the weight of each indicator to avoid subjective judgments; different alternatives are evaluated using the grey correlation analysis (GRA) and TOPSIS-integrated method which considers the distance and similarity between alternatives simultaneously.

By analyzing the characteristics and operation process of blockchain crowdfunding model, this paper formulates the evaluation index system from three dimensions of human resources, capital and publicity. In addition, the entropy method is used to calculate the weight of each indicator to avoid subjective judgments; different alternatives are evaluated using the GRA and TOPSIS-integrated method which considers the distance and similarity between alternatives simultaneously.

Blockchain crowdfunding has become a new model for fund-raisers to raise funds from public investors. This paper proposes a novel blockchain crowdfunding projects evaluation approach using extended TOPSIS under fuzzy environment.

This paper aims to study the influence of aerodynamics force of trains passing each other on the dynamic response of vehicle bridge coupling system based on numerical simulation and multi-body dynamics and put forward the speed threshold for safe running of train under different crosswind speeds.

The computational fluid dynamics method is adopted to simulate the aerodynamic force in the whole process of train passing each other by using dynamic grid technology. The dynamic model of vehicle-bridge coupling system is established considering the effects of aerodynamic force of train passing each other under crosswind, the dynamic response of train intersection on the bridge under crosswind is computed and the running safety of the train is evaluated.

The aerodynamic force of trains' intersection has little effects on the derailment factor, lateral wheel-rail force and vertical acceleration of train, but it increases the offload factor of train and significantly increases the lateral acceleration of train. The crosswind has a significant effect on increasing the derailment factor, lateral wheel-rail force and offload factor of train. The offload factor of train is the key factor to control the threshold of train speed. The impact of the aerodynamic force of trains' intersection on running safety cannot be ignored. When the extreme values of crosswind wind speed are 15 m·s⁻¹, 20 m·s⁻¹ and 25 m·s⁻¹, respectively, the corresponding speed thresholds for safe running of train are 350 km·h⁻¹, 275 km·h⁻¹ and 200 km·h⁻¹, respectively.

The research can provide a more precise numerical method to study the running safety of high-speed trains under the aerodynamic effect of trains passing each other on bridge in crosswind.

This study aims to investigate a chromium-free sealing treatment process to replace the chromate sealing process in response to the environmental hazards caused by chromate in the Phosphate chemical conversion (PCC) coating post-treatment sealing process.

In this paper, chromium-free sealing technology was used to post-treat PCC coatings. Scanning electron microscopy was used to investigate the structure of the surface of the PCC coatings after the sealing treatment, and the corrosion resistance, hydrophobicity and bonding were tested using an electrochemical workstation, a copper sulfate spot-drop test, a lacquer bonding test, a contact angle meter and a neutral salt spray test.

Chromium-free closure makes the grain distribution on the surface of the PCC coating more uniform and dense, and forms an organic film on the surface of the coating, which significantly improves the corrosion resistance and hydrophobicity of the PCC coating, does not affect the coating film bonding force and has similar performance with potassium dichromate solution.

The results show that the corrosion resistance of PCC coatings after chromium-free sealing treatment is improved, and chromium-free sealing has the potential to replace chromium sealing.

The purpose of this study is to prepare nanoscale copolymer-silicon dioxide (SiO₂) dispersion for formulating textile printing white ink.

Nanoscale copolymer-SiO₂ dispersion was prepared via miniemulsion polymerization. The miniemulsion formulation was optimized for preparing stable SiO₂/O/W miniemulsion and nanoscale copolymer-SiO₂ dispersion. The nanoscale copolymer-SiO₂ was investigated by transmission electron microscope (TEM), X-ray diffraction (XRD), differential thermal gravity (DTG) and thermogravimetric analysis (TGA). The performance of white inks from this colorant was further investigated.

Nanoscale copolymer-SiO₂ had a core-shell structure with about 45 nm encapsulated copolymer layer when it was synthesized under optimal miniemulsion formulation 60 per cent mass ratio of styrene (St) to KH570-SiO₂, 5.0 per cent hexadecane to St and 2.0 per cent concentration of DNS-86. The nanoscale copolymer-SiO₂ white ink had high thermal and centrifugal stability with high purity and color fastness.

The miniemulsion polymerization conditions required a careful control before favorable results could be achieved.

The nanoscale copolymer-SiO₂ dispersion and white ink prepared by this method showed excellent stability. This research could accelerate the textiles inkjet printing application.

The reactive stabilizer DNS-86 is innovatively introduced into the miniemulsion polymerization to improve the stability of the nanoscale copolymer-SiO₂ dispersion. The white ink was formulated from nanoscale copolymer-SiO2 to improve the fastness of the printed fabrics.

Assembly sequence planning (ASP) plays a vital role in assembly process because it directly influences the feasibility, cost and time of the assembly process. The purpose of this study is to solve ASP problem more efficiently than current algorithms.

A novel assembly subsets prediction method based on precedence graph is proposed to solve the ASP problem. The proposed method adopts the idea of local to whole and integrates a simplified firework algorithm. First, assembly subsets are generated as initial fireworks. Then, each firework explodes to several sparks with higher-level assembly subsets and new fireworks are selected for next generation according to selection strategy. Finally, iterating the algorithm until complete and feasible solutions are generated.

The proposed method performs better in comparison with state-of-the-art algorithms because of the balance of exploration (fireworks) and exploitation (sparks). The size of initial fireworks population determines the diversity of the solution, so assembly subsets prediction method based on precedence graph (ASPM-PG) can explore the solution space. The size of sparks controls the exploitation ability of ASPM-PG; with more sparks, the direction of a specific firework can be adequately exploited.

The proposed method is with simple structure and high efficiency. It is anticipated that using the proposed method can effectively improve the efficiency of ASP and reduce computing cost for industrial applications.

The proposed method finds the optimal sequence in the construction process of assembly sequence rather than adjusting order of a complete assembly sequence in traditional methods. Moreover, a simplified firework algorithm with new operators is introduced. Two basic size parameters are also analyzed to explain the proposed method.

The purpose of this paper is to develop an instrument/questionnaire to assess the supplier evaluation (SE) criteria and supplier selection (SS) benefits with their level of importance.

This paper develops an instrument/questionnaire based on generally accepted principle of instrument design to assess the SE criteria and SS benefits through the responses collected from 34 automobile industries in India. The SE criteria and SS benefits were derived through extensive literature review and expert’s opinion.

The reliability, normality and validity of developed instrument/questionnaire were determined through the responses collected from the managers of 34 automobile industries in India and are found to be acceptable for most of the SE criteria and SS benefits. The criterion validity is also found to be fairly good for the developed instrument/questionnaire.

While designing the instrument/questionnaire, SE criteria and SS benefits were considered for automobile sector in India through prequestionnaire sheet. Further, research may be required to corroborate these results from larger data sets.

Now a days, it is essential for organizations to rely on their suppliers for their survival and to gain competitive advantage. The well developed and validated instrument/questionnaire can be used for industry practitioners in Indian automobile industries to assess the SE criteria and SS benefits.

An empirically tested instrument/questionnaire is developed first time to assess the SE criteria and SS benefits for automobile sector in India.

The purpose of this paper is to understand the critical factors associated with growing fertilizer usage culminating in contamination of soil/water in agriculturally intensive regions of Uttar Pradesh, India. The agriculture sector is seen as one of the major contributors in ensuring food security, however adoption of sustainable agriculture to protect water resources from contamination due to fertilizers and pesticides is becoming pressing to achieve long term environmental security.

A two staged study aimed at monitoring the soil quality status followed by stakeholder survey has been attempted. Attitude-behavior framework based on the theory of reasoned action has been tried to explain the fertilizer use behavior in the study. The results are analyzed through Analysis of variance.

Soil monitoring data showed nitrate and total nitrogen loadings beyond the permissible limit in the identified regions. A questionnaire aimed at determining farmer’s attitude toward fertilizer usage showed a significant influence of factors like net farm income, overall farm yield, extension services, farmer characteristics on one hand and risks associated with changing farming practices, costs of substitutes available, market-based instruments like subsidies and loans on the other. Divergent responses were observed with respect to farmer’s perceived risks from adopting to organic substitutes, linkages of fertilizer application with environmental degradation and the level of adoption of sustainable agricultural practices.

The study can be scaled up to study the inter-regional differences by benchmarking regional responses. It would be interesting to extend the work to find solutions from the farmers as alternative fertility management strategies. The items used in questionnaire are self-made; hence there is still a possibility of enhancing the robustness of scale by applying advanced statistical techniques.

Results of the study indicate excessive nitrogen loadings in farm soils which is an indicator of potential future nitrate contaminated zones or vulnerable zones emerging in agricultural intensive regions. Findings reinforce the role of education, knowledge transfer and awareness for long-term agricultural sustainability. The paper highlights the urgency for reorientation of the support system by the government and policymakers.

The paper attempts to understand the linkage between the agricultural productivity and the environmental implications followed by the reasons culminating in the agri-environmental imbalance. On-site monitoring study followed by assessment of reasons culminating in this scenario has not been attempted earlier and this paper contributes to understanding at dual level. This paper emphasizes on the insights of stakeholder which is instrumental in ensuring agricultural sustainability or otherwise. It takes the position that the farmer’s farm management behavior is strongly influenced by factors like food security and income, keeping environmental quality at second place. It also identifies the barriers for organic farming and other alternative systems as well as explores the economic, social, and philosophical aspects of sustainable agriculture.

The purpose of this paper is to benchmark the energy use of Indian iron and steel industry. For this purpose, the authors have estimated a production frontier to know the best performing states. Further, the energy-saving targets are estimated to lie below the benchmark level for those states. Panel data for this purpose are extracted from the Annual Survey of Industry (an official database from the government of India) for 19 major steel-producing states over the period from 2004–2005 to 2013–2014.

The authors employed a radial and non-radial (slack-based measure) variant of the data envelopment analysis (DEA) to estimate the production frontier. Particularly, slack-based measures (SBMs) developed by Tone (2001) are used to get a more comprehensive measure of energy efficiency along with technical efficiency. Variable returns to scale technology is specified to accommodate market imperfection and heterogeneity across states. Four inputs (capital, labour, energy and material) and a single output are conceptualised for the production process to accommodate input substitution. The relative position of each state in terms of the level of energy efficiency is then identified.

The authors started by examining energy-output ratio. The average level of energy intensity shows declining trends over the period of time. States like Bihar, Jharkhand, Gujarat and Uttarakhand remain stagnant in the energy intensity level. SBM of energy efficiency shows an overall average energy saving potential of 8 per cent without reducing average output level. Considerable heterogeneity exists among states in terms of the energy efficiency scores. Further, the authors calculated scale efficiency (SE) which shows the overall average level of SE is 0.91; hence, the scale of operation is not optimal and needs to adjusted to enhance energy efficiency.

The authors demonstrate the empirical application of DEA with SBM to energy use performance. This is the first study that benchmarks Indian states in terms of the consumption of energy input to produce iron and steel by applying DEA.