Search results

This study discusses the tracking trajectory issue of the exoskeleton under the bounded disturbance and designs an useful tracking trajectory control method to solve it. By using the proposed control method, the tracking error can be successfully convergence to the assigned boundary. Meanwhile, the chattering effect caused by the actuators is already reduced, and the tracking performance of the pneumatic artificial muscles (PAMs) elbow exoskeleton is improved effectively.

A prescribed performance sliding mode control method was developed in this study to fulfill the joint position tracking trajectory task on the elbow exoskeleton driven by two PAMs. In terms of the control structure, a dynamic model was built by conforming to the adaptive law to compensate for the time variety and uncertainty exhibited by the system. Subsequently, a super-twisting algorithm-based second-order sliding mode control method was subjected to the exoskeleton under the boundedness of external disturbance. Moreover, the prescribed performance control method exhibits a smooth prescribed function with an error transformation function to ensure the tracking error can be finally convergent to the pre-designed requirement.

From the theoretical perspective, the stability of the control method was verified through Lyapunov synthesis. On that basis, the tracking performance of the proposed control method was confirmed through the simulation and the manikin model experiment.

As revealed by the results of this study, the proposed control method sufficiently applies to the PAMs elbow exoskeleton for tracking trajectory, which means it has potential application in the actual robot-assisted passive rehabilitation tasks.

This article aims to explore the potential of feminist phenomenology as a conceptual framework for advancing women’s entrepreneurship research and the suitability of interpretative phenomenological analysis (IPA) to the proposed framework.

The article critically examines the current state of women’s entrepreneurship research regarding the institutional context and highlights the benefits of a shift towards feminist phenomenology.

The prevailing disembodied and gender-neutral portrayal of entrepreneurship has resulted in an equivocal understanding of women’s entrepreneurship and perpetuated a male-biased discourse within research and practice. By adopting a feminist phenomenological approach, this article argues for the importance of considering the ontological dimensions of lived experiences of situatedness, intersubjectivity, intentionality and temporality in analysing women entrepreneurs’ agency within gendered institutional contexts. It also demonstrates that feminist phenomenology could broaden the current scope of IPA regarding the embodied dimension of language.

The adoption of feminist phenomenology and IPA presents new avenues for research that go beyond the traditional cognitive approach in entrepreneurship, contributing to theory and practice. The proposed conceptual framework also has some limitations that provide opportunities for future research, such as a phenomenological intersectional approach and arts-based methods.

The article contributes to a new research agenda in women’s entrepreneurship research by offering a feminist phenomenological framework that focuses on the embodied dimension of entrepreneurship through the integration of IPA and conceptual metaphor theory (CMT).

The research aims to investigate the impact of thermo-mechanical aging on SBR under cyclic-loading. By conducting experimental analyses and developing a 3D finite element analysis (FEA) model, it seeks to understand chemical and physical changes during aging processes. This research provides insights into nonlinear mechanical behavior, stress softening and microstructural alterations in SBR compounds, improving material performance and guiding future strategies.

This study combines experimental analyses, including cyclic tensile loading, attenuated total reflection (ATR), spectroscopy and energy-dispersive X-ray spectroscopy (EDS) line scans, to investigate the effects of thermo-mechanical aging (TMA) on carbon-black (CB) reinforced styrene-butadiene rubber (SBR). It employs a 3D FEA model using the Abaqus/Implicit code to comprehend the nonlinear behavior and stress softening response, offering a holistic understanding of aging processes and mechanical behavior under cyclic-loading.

This study reveals significant insights into SBR behavior during thermo-mechanical aging. Findings include surface roughness variations, chemical alterations and microstructural changes. Notably, a partial recovery of stiffness was observed as a function of CB volume fraction. The developed 3D FEA model accurately depicts nonlinear behavior, stress softening and strain fields around CB particles in unstressed states, predicting hysteresis and energy dissipation in aged SBRs.

This research offers novel insights by comprehensively investigating the impact of thermo-mechanical aging on CB-reinforced-SBR. The fusion of experimental techniques with FEA simulations reveals time-dependent mechanical behavior and microstructural changes in SBR materials. The model serves as a valuable tool for predicting material responses under various conditions, advancing the design and engineering of SBR-based products across industries.

This paper aims to propose an energetic model parameter calculation method for predicting the materials’ symmetrical static hysteresis loop and asymmetrical minor loop to improve the accuracy of electromagnetic analysis of equipment.

For predicting the symmetrical static hysteresis loop, this paper deduces the functional relationship between magnetic flux density and energetic model parameters based on the materials’ magnetization mechanism. It realizes the efficient and accurate symmetrical static hysteresis loop prediction under different magnetizations. For predicting the asymmetrical minor loop, a new algorithm is proposed that updates the energetic model parameters of the asymmetrical minor loop to consider the return-point memory effect.

The comparison of simulation and experimental results verifies that the proposed parameters calculation method has high accuracy and strong universality.

The proposed parameter calculation method improves the existing parameter calculation method’s problem of relying on too much experimental data and inaccuracy. Consequently, the presented work facilitates the application of the finite element electromagnetic field analysis method coupling the hysteresis model.

Although it is assumed that migration and tourism directly affect each other, neither has received enough attention in the literature. Moreover, the relationship between them remains unclear. The UNWTO interprets said relationship in two ways: tourism-led migration (TLM) and migration-led tourism (MLT). The latter is crucial for the marketing of tourism. This study aims to clarify the migration-tourism relationship in ways the relevant literature has inadequately addressed and to evaluate the significance of MLT for Turkey's tourism marketing.

The study was carried out with a qualitative research design. Document scanning was used to collect data. A time series analysis was performed based on secondary data. Vector autoregressive models (VARs), which test the relationship between two or more variables, were preferred in the analysis selection. The empirical evidence depends on annual data of German tourists visiting Turkey and persons admitted to Germany from 2006 to 2019.

The findings of the study revealed a significant short-term relationship between those immigrating to Germany and tourists visiting Turkey.

The research shows that migration is a factor in the purchasing behavior of touristic products. In this respect, the practical conclusion of the study reveals that it may be beneficial for national tourism marketers in these countries to promote touristic products through citizens who have migrated abroad.

In the relevant literature, the relationship between tourism and migration (RTM) has been limitedly examined from an MLT perspective. In this respect, the subject has not been examined in detail in many respects (distribution by years, various sampling and data collection technique, etc.). The present research helps fill this literature gap by addressing the subject directly.

The accurate modeling of magnetic hysteresis in electrical steels is important in several electrical and electronic applications. Numerical models have long been known that can correctly reproduce some typical behaviours of these magnetic materials. Among these, the model proposed by Jiles and Atherton must certainly be mentioned. This model is intuitive and fairly easy to implement and identify with relatively few experimental data. Also, for this reason, it has been extensively studied in different formulations. The developments and numerical tests made on this hysteresis model have indicated that it is able to accurately reproduce symmetrical cycles, especially the major loop, but often it fails to reproduce non-symmetrical cycles. This paper aims to show the positive aspects and highlight the defects of the different formulations in predicting the minor loops of electrical steels excited by non-sinusoidal currents.

The different formulations are applied to different electrical steels, and the data coming from the simulations are compared with those measured experimentally. The direct and inverse Jiles–Atherton models, including the introduction of the dissipative factor approach, are presented, and their limitations are proposed and validated using the measurements of three non-grain-oriented materials. Only the measured major loop is used to identify the parameters of the Jiles–Atherton model. Furthermore, the direct and inverse Jiles–Atherton models were used to simulate the minor loops as well as the hysteresis cycles with direct component (DC) bias excitation. Finally, the simulation results are discussed and compared to measurements for each study case.

The paper indicates that both the direct and the inverse Jiles–Atherton model formulations provide a good agreement with the experimental data for the major loop representation; nevertheless, both models can not accurately predict the minor loops even when the modification approaches proposed in the literature were implemented.

The Jiles–Atherton model and its modifications are widely discussed in the literature; however, some limitations of the model and its modification in the case of the distorted current waveform are not completely highlighted. Furthermore, this paper contains an original discussion on the accuracy of the prediction of minor loops from distorted current waveforms, including DC bias.

The theoretical findings serve as a foundation for further research into understanding sulfide-based solid-state electrolytes, ultimately advancing the progress of all-solid-state batteries.

The electronic properties of Li₇P₃S₁₁ are thoroughly explored through first-principles calculations.

This investigation encompasses the intricate atom-dominated valence and conduction bands, spatial charge density distribution and the breakdown of atom and orbital contributions to van Hove singularities. Additionally, the compound’s wide and discrete energy spectra reflect the substantial variations in bond lengths and its highly anisotropic geometric structure. The complex and nonuniform chemical environment indicates the presence of intricate hopping integrals.

This study provides valuable insights into the critical multiorbital hybridizations occurring in the Li-S and P-S chemical bonds. To validate the theoretical predictions, experimental techniques can be employed. By combining theoretical predictions with experimental data, a comprehensive understanding of the geometric and electronic characteristics of Li₇P₃S₁₁ can be achieved.

It is now well-established that good water quality is associated with economic prosperity, reduced incidence on public health and the good functioning of the various ecosystems found in our environment. Water contamination is mostly related to both diffused (agricultural lands and geologic rock degradations) and point sources of pollution. Mauritius has many water resources which depend solely on precipitation for their replenishment. Water parameters which are of relevance include total dissolved solids (TDS), temperature, pH, electrical conductivity, turbidity, dissolved oxygen, dissolved and particulate organic carbon and major cations and anions. The traditional methods of analysis for these parameters are mostly using electrical and optical methods (probes and sensors in the field), while chemical titrations, Flame AAS and High-Performance Liquid Chromatography techniques are carried out in the laboratory. Image Classification techniques using neural networks can also be used to detect the presence of contaminants in water. In addition to basic water quality parameters, the field sensors range have been extended to cover important major ions and can now be integrated with Artificial Intelligence (AI)-based models for the prediction of variations in water quality to better protect human health and the environment, reduce operation costs of water and wastewater treatment plant unit processes.

Construction sustainability (CS) is a strategic reaction to the sustainability expectations of the construction industry's external stakeholders. The extant literature has viewed the environmental, social and economic dimensions of CS as having independent effects on financial performance. Due to the influence of common stakeholders, however, interactions in these dimensions will be present in their effect on financial performance. Accordingly, this study identifies the mechanisms of the interactions between the three CS dimensions and how they jointly affect financial performance.

Content analysis of GRI reports of 60 large construction organisations, followed by a hierarchical regression analysis was used to identify the interactions between environmental, social and economic CS in their effect on financial performance.

Economic CS was found to indirectly, and not directly, affect financial performance, the effect being mediated by both environmental and social CS. Environmental CS was found to have a strong negative effect on financial performance, whilst social CS was found to have a strongly significant positive effect on financial performance.

The motivation for engaging in CS is that investment in economic CS will have a positive effect on both environmental and social CS outcomes, which, in turn can have a combined effect on financial performance.

This is one of the first studies investigating the effect of interactions between the environmental, social and economic CS dimensions on the financial performance of construction organisations. It is also one of the first studies that applies a sociotechnical framework to this relationship.

In the wake of the COVID-19 outbreak understanding the behavioral dynamics and role of knowledge-oriented leadership (KOL) in driving knowledge worker performance (KWP) is paramount for organizations striving to adapt and thrive in the post-pandemic era. Drawing on the path-goal theory, this study explores the impact of KOL on KWP. In addition, this study seeks to examine both the direct and indirect influences of KOL on KWP via digital orientation (DO) and digital citizenship practices (DCP), especially for higher education institutions (HEIs) located in China.

The sample consisted of 319 academic staff from HEIs in China. The study used Smart-PLS 4.0 for analytical examination.

The results indicate that the impact of knowledge-oriented leadership on KWP is negligible. Furthermore, DCP and DO partially mediate the relationship between KOL and KWP. The findings of this research have practical implications for Chinese HEIs and organizations across industries, providing insights into how to navigate the complexities of the post-pandemic work environment and effectively harness digitalization to optimize the KWP.

The implications of this research extend beyond the HEIs, providing organizations in various industries with evidence-based strategies to promote effective leadership, foster digital skills, and cultivate a culture of digital citizenship in the post-pandemic work landscape.

Despite the increasing significance of KOL in the higher education sector, there is a dearth of studies establishing a relationship between KOL and KWP in HEIs. The present study seeks to fill this gap by examining the association among KOL, KWP, DO, and DCP in HEIs during the post-pandemic. This research provides significant contributions to the existing literature on the topic by scientifically exploring the association between KOL and KWP by examining the intervention mechanism of both digital citizenship practices and digital orientation.