Search results

The purpose of this paper is to investigate the distribution characteristics of airflow in mine ventilation suits with different pipeline structures when the human body is bent at various angles. On this basis, the stress points are extracted to investigate the pressure variation of a ventilation suit under different ventilation rates and pipeline structures.

Based on the three-dimensional human body scanner, portable pressure test and other instruments, a human experiment was conducted in an artificial cabin. The study analyzed and compared the distribution characteristics of clearance under three different pipeline structures, as well as the pressure variation of the ventilation suit.

The study found that the clearance in front of two pipeline structures gradually increased in size as the degree of bending increased, and there was minimal clearance in the chest and back. The longitudinal structure exhibits a significant decrease in clearance compared to the spiral structure. The pressure value of the spiral pipeline structure with the same ventilation volume is low, followed by the transverse structure, while the longitudinal structure has the highest pressure value. The increase in clothing pressure value of a spiral pipeline structured ventilation suit with varying ventilation volumes is minimal.

The ventilation suit has a promising future as a type of personal protective equipment for mitigating heat damage in mines. It is of great value to study the pipeline structure of the ventilation suit for human comfort.

This study explores the adoption of Industry 4.0 in developing countries' export industries, focusing on factors influencing this adoption, the moderating role of market pressure and prioritizing key factors for sustainable growth.

Based on the “TOE theory” this study has proposed a research framework to identify the factors influencing the adoption and sustainable implementation of Industry 4.0 in the export industry. This study has collected valid datasets from 387 export-oriented industries and applied SEM-ANN dual-stage hybrid model to capture linear and nonlinear interaction between variables.

Results revealed that Technical Capabilities, System Flexibility, Software Infrastructure, Human Resource Competency and Market pressure significantly influence the Adoption of Industry 4.0. Higher market pressure as a moderator also improves the Industry 4.0 adoption process. Results also pointed out that system flexibility is a gray area in Industry 4.0 adoption, which can be enhanced in the export industry to maintain a sustainable adoption and implementation of Industry 4.0.

Minute information is available on the factors influencing the adoption of Industry 4.0 in export-oriented industries. This study has empirically explored the role of influential factors in Industry 4.0 and ranked them based on their normalized importance.

This study aims to develop an experimentally validated three-dimensional numerical model for predicting different flow patterns produced with a gas dynamic virtual nozzle (GDVN).

The physical model is posed in the mixture formulation and copes with the unsteady, incompressible, isothermal, Newtonian, low turbulent two-phase flow. The computational fluid dynamics numerical solution is based on the half-space finite volume discretisation. The geo-reconstruct volume-of-fluid scheme tracks the interphase boundary between the gas and the liquid. To ensure numerical stability in the transition regime and adequately account for turbulent behaviour, the k-ω shear stress transport turbulence model is used. The model is validated by comparison with the experimental measurements on a vertical, downward-positioned GDVN configuration. Three different combinations of air and water volumetric flow rates have been solved numerically in the range of Reynolds numbers for airflow 1,009–2,596 and water 61–133, respectively, at Weber numbers 1.2–6.2.

The half-space symmetry allows the numerical reconstruction of the dripping, jetting and indication of the whipping mode. The kinetic energy transfer from the gas to the liquid is analysed, and locations with locally increased gas kinetic energy are observed. The calculated jet shapes reasonably well match the experimentally obtained high-speed camera videos.

The model is used for the virtual studies of new GDVN nozzle designs and optimisation of their operation.

To the best of the authors’ knowledge, the developed model numerically reconstructs all three GDVN flow regimes for the first time.

The purpose of this study is to examine the dimensions of strategic intent (SI; see Appendix 1) according to the Hamel and Prahalad model as a building for the future, relying on today’s knowledge-based and proactive strategic directions of management as long-term and deep-perspective creative directions, objective vision and rational analysis, integrative in work, survival structure and comprehensiveness in perception.

The quantitative approach was used based on research, detection and proof, as data were collected from leaders amounting to 70 respondents and analyzed in the SPSS program and ant colony optimization (see Appendix 1) algorithm and interpretation of the results.

It was found that the SI dimensions are poorly available due to problems related to foresight, capabilities and the strategic structure that represents the head of strategic objectives.

The empirical evaluation view of the study is valuable for leaders to draw a future strategy of advantage for organizations in developing countries to enrich their core capabilities by activating the SI dimensions.

It stems from a vital issue related to strategic dimensions aimed at a better future for strategic executive work, especially after the crisis that led to a significant decline in the level of performance of organizations.

The metallic alloys and their components fabricated via laser powder bed fusion (LPBF) suffer from the microvoids formed inevitably due to the extreme solidification rate during fabrication, which are impossible to be removed by heat treatment. This paper aims to remove those microvoids in as-built AlSi10Mg alloys by hot forging and enhance their mechanical properties.

AlSi10Mg samples were built using prealloyed powder with a set of optimized LPBF parameters, viz. 350 W of laser power, 1,170 mm/s of scan speed, 50 µm of layer thickness and 0.24 mm of hatch spacing. As-built samples were preheated to 430°C followed by immediate pressing with two different thickness reductions of 10% and 35%. The effect of hot forging on the microstructure was analyzed by means of X-ray diffraction, scanning electron microscopy, electron backscattered diffraction and transmission electron microscopy. Tensile tests were performed to reveal the effect of hot forging on the mechanical properties.

By using hot forging, the large number of microvoids in both as-built and post heat-treated samples were mostly healed. Moreover, the Si particles were finer in forged condition (∼150 nm) compared with those in heat-treated condition (∼300 nm). Tensile tests showed that compared with heat treatment, the hot forging process could noticeably increase tensile strength at no expense of ductility. Consequently, the toughness (integration of tensile stress and strain) of forged alloy increased by ∼86% and ∼24% compared with as-built and heat-treated alloys, respectively.

Hot forging can effectively remove the inevitable microvoids in metals fabricated via LPBF, which is beneficial to the mechanical properties. These findings are inspiring for the evolution of the LPBF technique to eliminate the microvoids and boost the mechanical properties of metals fabricated via LPBF.

The evolution of modern digitalization technologies necessitates the development of a competitive digital supply chain quality management (SCQM) strategy by manufacturers. Using the new institutions and institutional theory (IIT), the study research first aims to identify the most important SCQM practices that can influence competitive performance (CP). Second, the authors intend to investigate the role of digital strategy alignment (DSA) in moderating the relationship between the multidimensionality of SCQM practices and CP among manufacturers.

The authors employ the Partial Least Squares-Structural Equation Modeling (PLS-SEM) technique to examine 225 valid samples from Malaysian manufacturers who use SCQM practices.

The study findings indicate that five of the twelve hypotheses developed were accepted. This suggests that supplier focus, strategic collaboration, information sharing and customer focus are positively and significantly correlated with CP. Unexpectedly, DSA moderates the relationship between leadership and CP.

This study extended the new IIT by empirically testing the six SCQM practices for CP in a DSA context, which can serve as a model for future research in the SCQM, CP and DS fields.

This study aims to improve the maneuverability and stability of four-wheel chassis in a small paddy field; a front axle swing steering four-wheel chassis with optimal steering is designed.

When turning, the front inner wheel stops and the rear inner wheel is in the following state. The hydraulic drive system of the walking wheel adopts a driving mode in which two front-wheel motors are connected in series and two rear wheel motors in parallel. The chassis uses a combination of a gasoline engine with a water cooling system, a CVT continuously variable transmission and a hydraulic drive system to increase the control capability. The front axle rotary chassis adopts a step-less variable speed engine and a hydraulic control system to solve the hydraulic stability of the chassis in uphill and downhill conditions so as to effectively control the over-speed of the wheel-side drive motors. Through the quadratic orthogonal rotation combination design test, the mathematical models of uphill and downhill front-wheel pressures and test factors are established.

The results show that the chassis stability is optimal when the back pressure is 0.5 MPa, and the rotating slope is 4°. The uphill and downhill pressures of the front wheels are 2.38 MPa and 1.5 MPa, respectively.

The influence of external changes on the pressure of hydraulic motors is studied through experiments, which lays the foundation for further research.

Due to the crisis originated by the COVID-19 pandemic, an important number of workers have been incorporating the telework modality. In this context, the distance from the workplace generates new dilemmas for work performance. In the paper the authors study the role of some individual and social antecedents on telework outcomes. In particular, they empirically investigate the direct relationship between trust (TR) and telework performance (PER) and explore mediators of that relationship such as social isolation (SI) and fatigue (FA).

A theoretical model with three main hypotheses is proposed and tested using partial least square structural equation modeling (PLS-SEM). The study sample, of an exploratory nature, consists of a dataset of 201 teleworkers working in Spanish companies.

The relevance of the proposed model is demonstrated and FA is found to be the factor that most affects (negatively) PER, followed by TR (positively) and SI (negatively). Beyond the direct effects, the results provide support for the role of SI and FA in mediating the relationship between TR and PER.

This paper discusses the PER dilemma and proposes and tests a background model that may be useful for future research. The results are of interest to human resource managers, consultants, academics and telework tool developers and managers. Practices are proposed to improve TR or to reduce feelings of SI or FA. The research provides a practical evaluation tool for telework implementation.

This study aims to investigate the impact of regular Kung Fu and Taekwondo practice on the health and quality of life among elderly individuals in the Maule region, Chile.

The authors designed a 12-week Kung Fu and Taekwondo workshop with activities suitable for their age. Through semistructured interviews (at the beginning and the end of the workshop), along with periodic monitoring of vital signs and cardiovascular components, the authors observed an improvement in participants’ physical (strength, speed of reaction and flexibility) and psychological conditions (self-esteem and resilience), quality of life (relationships with family and friends and ability to deal with stressful events in working life) and health (waist circumference, percentage of oxygen saturation in blood, blood pressure, among other values).

From these results, the authors affirm that this workshop improves health and physical condition and helps the participants develop the coping capacity to deal with stressful situations and complicated interpersonal relationships. In this sense, the authors conclude that Kung Fu and Taekwondo as regular sports activities can benefit senior citizens’ aging process.

This research is based on an original study project.

At the dawn of a new decade, as ever more corporations are pursuing sustainable working conditions and advocating employee well-being, employees are increasingly tending to feel fatigued and drained by their work, which compromises their performance. Drawing on the job demands–resources model and social acceleration debate, the authors test a moderated mediation model. Specifically, the authors hypothesise that unreasonable tasks raise perceptions of emotional exhaustion when the pace of work is increased and investigate the moderating role of psychological detachment.

This study used a sample of 245 employees from Europe, all knowledge workers, to test the hypotheses.

Apart from unreasonable tasks being directly related with emotional exhaustion, this relationship was mediated by the perceived work pace. In addition, the authors establish psychological detachment as a relevant moderator for the mediating effect.

Managers and HR practitioners are equipped with a better understanding of the effects of an increasing speed of work, the conditions leading to it and the individual and organizational resources that may help to create healthy and meaningful job positions, which facilitate employee efficiency.

Our study expands the literature on contemporary stressors and adds to what is known about the ‘dark side’ of job demands that affect the organizational bottom-line, as well as the resource-based mechanism that can buffer the negative effects.