Search results

This study aims to evaluate the efficiency of using some polymers at different concentrations in the consolidation of vegetable-tanned leather artifacts.

New vegetable-tanned leather samples were prepared. The consolidants used were polyacrylamide (PAM) and polymethyl methacrylate/hydroxyethyl methacrylate (MMA-HEMA). Accelerated heat aging was applied to the untreated and treated samples. Analytical techniques used were Fourier transform infrared spectroscopy (FTIR), digital microscope, scanning electron microscope (SEM), change of color and mechanical properties.

The characteristic FTIR bands showed the effect of accelerated heat aging on the molecular structure of the studied samples, but treated and aged treated samples used were better than aged untreated samples. Microscopic investigations (digital and SEM), and mechanical properties proved that 2% was the best concentration for polymers used. The change in the total color difference of the treated and aged treated samples was limited.

This study presents the important results obtained from PAM and poly(MMA-HEMA) used for the consolidation of vegetable-tanned leather artifacts. The best results of the studied polymers can be applied directly to protect historical vegetable-tanned leathers.

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.

As aging populations lead to longer working lives and increasing automation threatens job security, maintaining lifelong employability is becoming a fundamental challenge for many individuals. The purpose of this study is to examine how lifelong employability can be maintained.

Based on the theoretical perspectives of both movement capital and selection, optimization and compensation (SOC) theories, we used large-scale survey data (N = 2,256) from three European countries to investigate strategies for preserving employability among aging workers. Specifically, we explored the perceived risk of automation, lifelong learner characteristics and self-efficacy for occupational mobility as boundary conditions that may shape the negative relationship between age and employability.

We found a negative relationship between age and employability, which was more pronounced when the perceived risk of automation was higher. Furthermore, lifelong learner characteristics and self-efficacy for occupational mobility mitigated the negative relationship, so that age was not related to employability if people possessed lifelong learner characteristics and were ready for a career change.

Our study implies the importance of investing in enhancing lifelong learner characteristics and self-efficacy for occupational mobility for older employees.

Paper aims to evaluate the efficiency of traditional chitosan, nano chitosan, and chitosan nanocomposites for consolidating aged papyrus samples. Cellulose-based materials, such as papyrus sheets and paper, which are the most common types of writing supports for works of art in many museums and archive. They are subjected to different types of deterioration factors that may lead to many conservation problems. Consolidation treatment is one of the most common conservation treatments, which should have perform after much testing to select the appropriate consolidants.

This research paper aims to evaluate the resistance of traditional chitosan, nanochitosan and chitosan/zinc oxide nanocomposite as an eco-friendly papyrus strengthening. Untreated and treated papyrus was thermally aged and characterized via scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). Antimicrobial activity of the papyrus specimens was also determined against four tested pathogenic bacteria by disc diffusion method: MRSA, Staphylococcus aureus, E. coli and P. aeruginosa.

The results revealed that chitosan nanocomposite showed a remarkable enhancement of papyrus tensile properties and presence of ZnO prevents the effects of biodeterioration.

Zinc oxide nanoparticles enhance the optical properties and increase the chemical reactions between the consolidating material and the treated papyrus.

This study aims to investigate the behavior of the green biomass-derived copper (lignin/silica/fatty acids) complex, copper lignin/silica/fatty acids (Cu-LSF) complex, when incorporated into the nonpolar ethylene propylene diene (EPDFM) rubber matrix, focusing on its reinforcing and antioxidant effect on the resulting EPDM composites.

The structure of the prepared EPDM composites was confirmed by Fourier-transform infrared spectroscopy, and the dispersion of the additive fillers and antioxidants in the EPDM matrix was investigated using scanning electron microscopy. Also, the rheometric characteristics, mechanical properties, swelling behavior and thermal gravimetric analysis of all the prepared EPDM composites were explored as well.

Results revealed that the Cu-LSF complex dispersed well in the nonpolar EPDM rubber matrix, in thepresence of coupling system, with enhanced Cu-LSF-rubber interactions and increased cross-linking density, which reflected on the improved rheological and mechanical properties of the resulting EPDM composites. From the various investigations performed in the current study, the authors can suggest 7–11 phr is the optimal effective concentration of Cu-LSF complex loading. Interestingly, EPDM composites containing Cu-LSF complex showed better antiaging performance, thermal stability and fluid resistance, when compared with those containing the commercial antioxidants (2,2,4-trimethyl-1,2-dihydroquinoline and N-isopropyl-N’-phenyl-p-phenylenediamine). These findings are in good agreement with our previous study on polar nitrile butadiene rubber.

The current study suggests the green biomass-derived Cu-LSF complex to be a promising low-cost and environmentally safe alternative filler and antioxidant to the hazardous commercial ones.

Many European countries suspended mandatory conscription after the Cold War, and especially between 2000 and 2010. However, with the changing security situation in Europe, more and more countries are considering the re-introduction of the draft. That is why, it is important to evaluate the impact of conscription on draftees, including its effect on fertility outcomes. Additionally, fertility is of particular interest because birth rates have been below replacement levels in most European countries at least in the last two decades. This, combined with the increase in life expectancy, has contributed to aging population and raises concerns about the future economic prospects and sustainability of the continent. Military service could be related to fertility in several ways. Compulsory service for men would affect the marriage market and subsequently child-bearing outcomes. For example, men who serve in the military would have to delay higher education at least by a year, given that they plan to continue their education after high school. One possibility is that this leads to older men meeting younger women if partners meet at college. Alternatively, in case the partners know each other prior to the draft, service could delay marriage by up to a year due to the conscription, postponing planning and having children, and potentially having fewer children as women might be less able or less willing to have a child after a certain age. Finally, some men who plan and would otherwise continue their education might choose to not do so or to further postpone it once they disattach from studying during their service. For some men, this might influence their marital and subsequent fertility outcomes. In either of these scenarios, a draft or its suspension is likely to be connected to fertility.

This study examines the effect of the suspension of the draft in Spain in December 2001 on three fertility outcomes of men that would have been drafted in the absence of the suspension. The author performs the analysis in a difference-in-differences framework. Potential concerns and policy implications are also discussed.

The findings suggest that after the suspension of the draft, individuals started to have their first child earlier given that they decide to have children. Consistent with the overall time trend, they became less likely to have a child and started to have fewer children. However, the age at birth of the first child decreased while the number of children and the likelihood of having a child increased for men relative to women, after compared to before the suspension of the mandatory draft.

The author extends prior literature by investigating the effect of the abolition of compulsory military service in Spain in December 2001 on fertility. This is novel is several ways. First, to the best of the author’s knowledge, previous literature has examined the effect of this Spanish reform only on labor market outcomes prior to men's conscription. Second, even for other countries that terminated the compulsory draft, fertility has been under-studied, providing an opportunity for further exploration. Third, this analysis is based on rich Census data, representative of the population in Spain. Finally, given the inconclusive findings of previous studies for other countries and the proposed re-introduction of the draft in some parts of Europe, additional evidence of the effect of the conscription has important policy implications necessary for the evaluation of future military service policy decisions.

This paper aims to investigate the influence of health beliefs and trust by senior adults as associated with the perceived ease of use and perceived usefulness, for the acceptance of smart technology with a focus on smartwatch technology.

Structural equation modeling is used to conceptualize the model using survey data collected from 243 randomly selected senior adults 60+ years of age.

This paper presents that perceived usefulness, perceived ease of use, trust and health belief are direct and indirect predictors of senior adults’ technology acceptance and intention to use smartwatch technology.

The study reveals the moderator effect of social influence on relation between perceived usefulness, perceived ease of use and intention to use. The authors highlight the effect of health belief and trust on perceived usefulness and perceived ease of use and the role of intention to use smartwatch technology.

The authors contribute bridging developers of health technologists and senior adults as end-user perspectives. For marketing of health-care technology products, specifically smartwatch, to seniors, a focus on health beliefs and trust is essential to build, maintain and improve perceived usefulness and perceived ease of use.

The present study contributes empirical evidence to the literature on factors affecting the acceptance of the smartwatch technology by senior adults.

This chapter provides a comprehensive exploration of global demographic trends and challenges, specifically focusing on Asian countries and the demographic landscape of Bangladesh. This chapter highlights the implications of rapid population growth, aging populations, and urbanization, analyzing their socioeconomic impacts on education, healthcare, and employment. By contextualizing these trends within the broader framework of sustainable development, this chapter sets the stage for understanding the intricate relationship between population dynamics and the empowerment of marginalized communities through family planning strategies.

This study aims to examine the influence of condominium attributes on resident satisfaction and word of mouth from the perspectives of the elderly in Thailand.

Data were collected from 338 elderly residents through a questionnaire survey and analysed by using descriptive statistics and structural equation modelling procedures.

The results showed that the strongest predictor of resident satisfaction was design functionality, followed by social environment, safety and security and service quality. In addition, the strongest predictor of word of mouth was safety and security, followed by design functionality, proximity, service quality and social environment.

The data were drawn at the level of the overall characteristics of elderly residents. People may be different in terms of their demographic characters such as gender, age, and user experience.

The study suggests that condominium developers and designers should pay attention to design functionality both physically and mentally such as suitable materials, lighting and common areas. Moreover, the developers should focus on the proximity of the nearest hospitals, safety and security measures, well-trained security personnel and social activity arrangement.

Elderly condominium markets are increasingly growing as a result of the ageing society in Thailand. However, very few empirical studies investigate condominium attributes that affect resident satisfaction and word of mouth provided by real estate developers. The paper aims to determine driving factors that enhance the better well-being of elderly residents.

Polymer laser powder bed fusion (PBF-LB/P) is an additive manufacturing technology that is sustainable due to the possibility of recycling the powder multiple times and allowing the fabrication of gears without the aid of support structures and subsequent assembly. However, there are constraints in the process that negatively affect its adoption compared to other additive technologies such as material extrusion to produce gears. This study aims to demonstrate that it is possible to overcome the problems due to the physics of the process to produce accurate mechanism.

Technological aspects such as orientation, wheel-shaft thicknesses and degree of powder recycling were examined. Furthermore, the evolving tooth profile was considered as a design parameter to provide a manufacturability map of gear-based mechanisms.

Results show that there are some differences in the functioning of the gear depending on the type of powder used, 100% virgin or 50% virgin and 50% recycled for five cycles. The application of a groove on a gear produced with 100% virgin powder allows the mechanism to be easily unlocked regardless of the orientation and wheel-shaft thicknesses. The application of a specific evolutionary profile independent of the diameter of the reference circle on vertically oriented gears guarantees rotation continuity while preserving the functionality of the assembled mechanism.

In the literature, there are various studies on material aging and reuse in the PBF-LB/P process, mainly focused on the powder deterioration mechanism, powder fluidity, microstructure and mechanical properties of the parts and process parameters. This study, instead, was focused on the functioning of gears, which represent one of the applications in which this technology can have great success, by analyzing the two main effects that can compromise it: recycled powder and vertical orientation during construction.