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The purpose of this study is to systematically analyze the wear of cylindrical needle bearings in rotary vector reducers under temperature rise and identify the influencing factors.

Based on the dynamic characteristics of the RV-20E reducer, the time-varying contact force of the cylindrical needle bearing and the entrainment speed of the inner and outer raceways were calculated. A mixed elastohydrodynamic lubrication model of the needle bearing, considering friction and temperature rise, was established using a dynamic rough tooth surface model. The model solved for the oil film thickness, contact stress and wear conditions of the bearing raceway contact area. The effects of the number of rolling needles, the diameter of rolling needles and surface strength on the wear characteristics were analyzed.

The results of this study show that the oil film thickness, oil film pressure and surface scratches of cylindrical needle bearings exhibit an uneven, patchy distribution under the combined effects of friction and temperature rise. When the radius of the rolling needle is less than 1.44 mm, inner ring wear is less than outer ring wear. Conversely, when the radius exceeds 1.44 mm, inner ring wear is greater. The optimal rolling needle radius is 1.6 mm. Increasing the number of rolling needles and enhancing the yield strength of the contact surface significantly extend bearing life.

This study provides valuable recommendations for optimizing bearing structural parameters and material characteristics in the design of rotary vector reducers.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2024-0242/

This paper aims to map the evolution of hydrogen-based technologies (HBTs) by examining the patenting activity associated to these technlogies from 1930 to 2020. In doing so, the study provides a novel perspective on the development of HBTs and offers implications for managers and policymakers.

We collected patent data at the level of patent families (PFs). Our sample includes 317,089 PFs related to hydrogen production and 62,496 PFs to hydrogen storage. We examined PF data to delineate the state of the art and major technical advancements of HBTs.

Our analysis provides evidence of an increasing patenting activity in the area of HBTs, hence suggesting relatively high levels of expectations on the economic potential of these technologies. US and Japan hold the largest proportion of PFs related to HBTs (about 60%), while European applicants hold the highest proportion of highly cited PFs (about 60%). While firms represent the applicant with the highest share of PFs, our analysis reveals that firms holding HBT PFs are primarily from the chemical sector.

While our analysis is limited to examining patent data which capture some aspects of the innovation activity around HBTs (namelly, patented inventions), our study enriches existing literature by performinng a patent analysis on a much larger sample of data when compared to previous studies.

Two main implications emerge from our study. Firstly, there seems to be an urgent need to support the emergence of a dominant design so as to facilitate the consolidation and diffusion of the HBTs, hence the transition to a more sustainable energy production. Secondly, the majority of HBT PFs are held by a small number of countries. This, in turn, suggests opportunities to develop cross-country cooperation (e.g. international agreements, research and technology offices) to support the development and adoption of HBTs globally.

Considering the results obtained in this study, from a social point of view, the attention that organizations have paid to hydrogen related technologies is evident. This suggests that the development HBTs can function as a social enabler for a sustianable energy transition.

Extant research has focused on the individual components of the hydrogen chain. As a result, we lack a comprehensive understanding of the progress made in the area of HBTs. To address this gap, this study examined HBTs by focusing on both production and storage technologies since their initial developments, hence adopting an observation period of about 70 years.

The purpose of the study is to examine the factors that influence people's intention to adopt electric vehicles (EVs). The study used an expanded theory of planned behaviour (TPB) along with the addition of perceived trust and consideration of future consequences (CFC).

The study is based on primary data collected from 282 respondents in Punjab through a questionnaire. The collected data were analysed using SPSS 26 and AMOS 24 to perform confirmatory factor analysis and structural equation modelling.

The empirical analysis indicates that attitude, subjective norms and perceived trust have a significant influence on the adoption intention (AI) of EVs.

The implications provide policymakers and marketers with better insights into marketing EVs in the trajectory of sustainable mobility. Marketers should create focussed marketing materials that highlight the environmental ease of use, lower running costs and sophisticated technology of electric automobiles. The limitations of the study provide valuable insights for future researchers.

This is the first study that uses CFC with the TPB model in the context of AI of EVs specifically for the Punjab region.

This study aims to explore the possibility of using magnetic biochar composite (MBCC) derived from Heglig tree bark (HTB) powder (agricultural solid waste) and cobalt ferrite (CoFe₂O₄, CFO) for oil spill removal from seawater surface.

One-pot co-precipitation route was used to synthesize MBCC. The prepared materials were characterized by X-ray diffraction, scanning electron microscopy-energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy. The densities of the prepared materials were also estimated. Crude, diesel engine and gasoline engine oils were used as seawater pollutant models. The gravimetric oil removal (GOR) method was used for removing oil spills from seawater using MBCC as a sorbent material.

The obtained results revealed that the prepared materials (CFO and MBCC) were able to remove the crude oil and its derivatives from the seawater surface. Besides, when the absorbent amount was 0.01 g, the highest GOR values for crude oil (31.96 ± 1.02 g/g) and diesel engine oil (14.83 ± 0.83 g/g) were obtained using MBCC as an absorbent. For gasoline engine oil, the highest GOR (27.84 ± 0.46 g/g) was attained when CFO was used as an absorbent.

Oil spill removal using MBCC derived from cobalt ferrite and HTB. Using tree bark as biomass (eco-friendly, readily available and low-cost) for magnetic biochar preparation also is a promising method for minimizing agricultural solid wastes (e.g. HTB) and obtaining value-added-products.

This paper aims to reveal the influence of the grooved texture parameters on the lubrication performance of circular pocket-roller pairs in cylindrical roller bearings.

In this paper, the thermal elastohydrodynamic lubrication mathematical model of the grooved texture circular pocket-roller pair was established, the finite difference method and successive over-relaxation method were used to solve the model, the influence of texture quantity, texture depth and texture area ratio on circumferential bearing capacity, friction coefficient, maximum temperature rise, stiffness and damping of the circular pocket-roller pairs were analyzed.

The results show that texture quantity, texture depth and texture area ratio significantly influence the static and dynamic characteristics of circular pocket-roller pairs. The suitable surface groove texture parameters can dramatically improve the circumferential bearing capacity, reduce the friction coefficient, inhibit the maximum temperature rise and increase the stiffness and damping of the circular pocket-roller pairs.

The research in this paper can provide a theoretical basis for the optimization design of pockets in cylindrical roller bearings to reduce friction and vibration.

Sustainability transitions (STs) refer to large-scale step changes in complex systems required to face sustainability issues. We aim to delineate how they can unfold in service ecosystems, especially when inspired by regenerative thinking.

We develop a conceptual framework based on a processual view of STs and provide a propositional inventory based on literature leveraging deductive reasoning. Moreover, we contextualize our conceptualizations by showing illustrative examples of cities coping with STs.

We connect the perception of unsustainability with the shift toward service-dominant (S-D) logic and identify them as triggers of an ST; we focus on the role of nested service ecosystems and the adoption of regenerative thinking in STs; finally, we highlight the domino effect that can drive continuous change towards sustainability in service ecosystems. Future research could be focused on (loss of) sensemaking for driving STs, practical approaches to deal with institutional tensions in nested service ecosystems and the possible fractality of ST processes in service ecosystems.

This study supports the understanding of STs in cities and other systems such as industries, markets and organizations. It contributes to ST literature by suggesting the adoption of S-D logic and system lenses to identify, drive and cope with system changes toward sustainability, showing implications for policymakers and practitioners. Furthermore, it contributes to S-D logic by unfolding the self-adjustment of service ecosystems and the focus of sustainability initiatives on nested service ecosystems to sustain the broader systems. Finally, it contributes to transformative service research by identifying how the procedural and inspirational principles characterizing regenerative thinking can support design for STs.

This paper aims to prepare an oil-impregnated porous polytetrafluoroethylene (PTFE) composite with advanced tribological properties using citric acid as a novel pore-forming agent.

Citric acid (CA) was used to form pores in PTFE, and then oil-impregnated PTFE composites were prepared. The pore-forming efficiency of CA was evaluated. The possible mechanism of lubrication was proposed according to the tribological properties.

The results show CA is an efficient pore-forming agent and completely removed, and the porosity of the PTFE increases with the increase of the CA content. The oil-impregnated porous PTFE exhibits an excellent tribological performance, an increased wear resistance of 77.29% was realized in comparison with neat PTFE.

This study enhances understanding of the lubrication mechanism of oil-impregnated porous polymers and guides for their tribological applications.

This study aims to investigate the dynamics between exogenous shocks, financial stress and economic performance in the USA from January 1995 to August 2023.

Granger-causality tests and impulse response analyses are used to examine causal relationships and dynamic responses among crude oil prices, real M2 money supply, financial stress and key economic indicators.

This study reveals a significant correlation between elevated financial stress and reduced real output, along with disruptions in the labor market, potentially leading to economic recessionary trends. Failure to address these challenges could perpetuate labor market difficulties, weaken capital accumulation within the loanable funds market and ultimately hinder long-term economic growth prospects in the USA.

This study offers insights for policymakers to mitigate financial stress. Recommendations include enhancing financial surveillance, strengthening regulatory frameworks, promoting economic diversification and implementing countercyclical policies to stabilize the economy and support labor markets. In addition, proactive monitoring of financial stress indicators can serve as early warning signals, aiding in timely interventions and effective risk management strategies.

This research provides a comprehensive analysis of how the financial stress index (FSI) mediates the effects of external shocks on the US economy, addressing a gap in existing literature. The integration of the FSI into the analysis enhances the understanding of the transmission channels through which external shocks influence the economy.

For the sake of sustainable development and environmental preservation, it is crucial to develop UV-curable coatings composed of renewable resources. Castor oil, being both bio-based and economical, serves as the focal point of this research paper. The purpose of this research paper is to synthesize, formulate and apply a UV-curable biobased oligomer ECOSAGMA as a wood coating, with a focus on sustainable development and environmental preservation. Castor oil, being both bio-based and economical, serves as the focal point of this research paper.

ECOSAGMA was prepared by reacting epoxidized castor oil with sebacic acid, followed by reaction with glycidyl methacrylate through ring opening reaction. The chemical structure of ECOSAGMA was confirmed by Fourier-Transform infrared spectroscopy, 13C-NMR and 1H-NMR spectroscopy. The synthesized oligomer was used for UV-curable coating formulations by combining it with varying amounts of TMPTA from 10 to 40 wt.% and studied for their rheological properties. The UV curable formulations were co-photopolymerized into thin coatings and were thoroughly examined based on thermal, chemical and mechanical properties.

The UV-cured coating containing ECOSAGMA and TMPTA exhibits exceptional mechanical, chemical and thermal properties, underscoring their potential for deployment in real-world application. It is observed that an increase in the concentration of TMPTA is associated with a notable enhancement in the properties of the UV-cured coatings. The UV-cured wood coating, composed of 40 wt.% TMPTA, demonstrates remarkable stain resistance properties.

In conclusion, by embracing eco-friendly and economically conscious principles., it is evident that this synthesized novel castor oil-based oligomer offers a range of valuable properties to the coating such as stain resistance and thermal stability as well as characteristics such as gloss, hardness, adhesion and chemical resistance.

This study aims to get rid of non-degradable polyvinyl chloride (PVC) waste as well as sunflower seed cake (SSC) waste by preparing eco-friendly composites from both in different proportions to reach good mechanical and insulating properties for antimicrobial and antistatic applications.

Eco-friendly composite films based on waste polyvinylchloride (WPVC) and SSC of concentrations (0, 10, 20, 30 and 40 Wt.%) were prepared using solution casting method. Further, the effect of sunflower seed oil (SSO) on the biophysical properties of the prepared composites is also investigated. Fourier transform infrared spectroscopy, X-ray diffraction (XRD), scanning electron microscope, mechanical, thermal, dielectric properties were assessed. Besides, the antimicrobial and biodegradation tests were also studied.

The crystallinity increases by rising SSC concentration as revealed by XRD results. Additionally, the permittivity (ε′) increases by increasing SSC filler and SSO as well. A remarkable increase in dc conductivity was attained after the addition of SSO. While raw WPVC has very low bacterial activity. The composite films are found to be very effective against staphylococcus epidermidis, staphylococcus aureus bacteria and against candida albicans as well. On the other hand, the weight loss of WPVC increases by adding of SSC and SSO, as disclosed by biodegradation studies.

The study aims to reach the optimum method for safe and beneficial disposal of PVC waste as well as SSC for antistatic and antimicrobial application.