Search results

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.

Finite element (FE) analysis can be used for both design and verification of components. In the case of 3D-printed materials, a proper characterization of properties, accounting for anisotropy and raster angles, can help develop efficient material models. This study aims to use compression tests to characterize short carbon-reinforced PA12 made by fused filament fabrication (FFF) and to model its behaviour by the FE method.

In this work, the authors focus on compression tests, using post-processed specimens to overcome external defects introduced by the FFF process. The material’s elastoplastic mechanical behaviour is modelled by an elastic stiffness matrix, Hill’s anisotropic yield criterion and Voce’s isotropic hardening law, considering the stacking sequence of raster angles. A FE analysis is conducted to reproduce the material’s compressive behaviour through the LS-DYNA software.

The proposed model can capture stress values at different deformation levels and peculiar aspects of deformed shapes until the onset of damage mechanisms. Deformation and damage mechanisms are strictly correlated to orientation and raster angle.

The paper aims to contribute to the understanding of 3D-printed material’s behaviour through compression tests on bulk 3D-printed material. The methodology proposed, enriched with an anisotropic damage criterion, could be effectively used for design and verification purposes in the field of 3D-printed components through FE analysis.

Because of the anisotropy of the process and the variability in the quality of printed parts, finite element analysis is not directly applicable to recycled materials manufactured using fused filament fabrication. The purpose of this study is to investigate the numerical-experimental mechanical behavior modeling of the recycled polymer, that is, recyclable polyethylene terephthalate (rPET), manufactured by a deposition FFF process under compressive stresses for new sustainable designs.

In all, 42 test specimens were manufactured and analyzed according to the ASTM D695-15 standards. Eight numerical analyzes were performed on a real design manufactured with rPET using Young's compression modulus from the experimental tests. Finally, eight additional experimental tests under uniaxial compression loads were performed on the real sustainable design for validating its mechanical behavior versus computational numerical tests.

As a result of the experimental tests, rPET behaves linearly until it reaches the elastic limit, along each manufacturing axis. The results of this study confirmed the design's structural safety by the load scenario and operating boundary conditions. Experimental and numerical results show a difference of 0.001–0.024 mm, allowing for the rPET to be configured as isotropic in numerical simulation software without having to modify its material modeling equations.

The results obtained are of great help to industry, designers and researchers because they validate the use of recycled rPET for the ecological production of real-sustainable products using MEX technology under compressive stress and its configuration for numerical simulations. Major design companies are now using recycled plastic materials in their high-end designs.

Validation results have been presented on test specimens and real items, comparing experimental material configuration values with numerical results. Specifically, to the best of the authors’ knowledge, no industrial or scientific work has been conducted with rPET subjected to uniaxial compression loads for characterizing experimentally and numerically the material using these results for validating a real case of a sustainable industrial product.

In the scope of the immense growth of corporate frauds and scandals, reporting unethical practices could be considered as an important mechanism to control them and ultimately improve organizational quality. To this end, this study proposes the conceptual framework comprising the enablers impacting employees' tendencies and behaviors to reporting misdemeanor in the workplace.

Systematic review of literature has been carried out. To understand the complexities among various enablers and to analyze their driving power and contingencies, a modified total interpretive structural modeling (TISM) approach has been adopted.

The findings indicate that enablers such as moral identity (MI) and job satisfaction (JS) having higher driving power (come at the bottom of the hierarchy) are relatively more important. Furthermore, perceived personal cost (PC), moral courage (MC), self-efficacy (SE) and anger have high dependent power of factors. Finally, the paper provides two paths that can lead to whistleblower's ethical decision.

A conceptual framework delivered in this paper requires to test against the field data. However, the conceptual understanding of driving enablers paves the way to top management in recruiting and hiring people in the workplace.

This study represents the first attempt to apply TISM for whistleblowing phenomenon. It provides a comprehensive conceptual framework in order to address the relative importance of various individual enablers in developing reporting tendencies against misdemeanors.

This paper aims to verify how the intellectual property (IP) box affects firms’ effective tax rate, growth and innovation activity outcomes related to intellectual property rights.

Implementing the innovation box regimes into the tax system intends to encourage firms to engage in more innovative activities. In UK, Italy and Poland, the IP box tax relief was introduced in 2013, 2015 and 2019, respectively. In return, companies may reduce their tax rate to increase their investment and innovativeness. With a panel model approach – system GMM and DiD with multiple time periods – it analyses data from the Orbis database for 2011–2019 of 673 firms from the gaming industry in 11 countries and hand-collected data on intellectual property rights protection. The authors study public and private companies from the gaming sector in leading European markets and all three countries that protect intellectual property rights of software (Japan, South Korea, the USA).

Recent reforms enable gaming companies to use preferential tax treatment for IP-related income and significantly impact a firm’s revenue growth.

Nevertheless, European gaming firms require time to leap the gap to the growth and innovativeness of countries that protect software.

The authors show that the IP box stimulates gaming firms to protect IP via wordmarks, figurative marks, trademarks and software patents that bring effects in five years. Despite the critics against IP box, the authors prove its lagged efficiency, especially in profitable and larger firms.

The purpose of this paper is to examine the role of both supervisory abuse and moral efficacy in the weakening or strengthening of moral courage. The study also tests how the interaction between both could influence moral courage.

Cross-sectional data were collected from a sample of public hospital nurses in Egypt and structural equation modeling was used to analyse the data.

The study findings revealed that abusive supervision is negatively related to moral courage whereas moral efficacy is positively related to courage. Furthermore, moral efficacy moderates the abusive supervision-moral courage relationship in such a way that the negative association between abusive supervision and moral courage is reduced when moral efficacy is high.

Because of the cross-sectional design of the study, inferences regarding causality cannot be made. Furthermore, more research is needed to identify whether the results of this study apply in other contexts.

Organizations should identify abusive supervisors and offer them abuse-prevention training to circumvent their hostile behaviour. Organizations should also try to consider follower moral efficacy when matching supervisors with followers.

The study addresses calls for research on the personal factors that could mitigate the undesirable effects of abusive supervision.

This study aims to investigate how media content consumed through immersive technology may evoke changes in human rights attitudes. It has been proposed that our inability to empathize with others could be overcome by stepping into another's shoes. “Immersive journalism” has been postulated as being able to place us into the shoes of those whose feelings and experiences are distant to us. While virtual reality (VR) and 360-degree news videos have become widely available, it remains unclear how the consumption of content through immersive journalism affects users' attitudes.

Utilizing a between-subject laboratory-controlled experiment (N = 87) this study examined participant scores on the Human Rights Questionnaire before and after consuming 360-degree video immersive journalism content via VR (n = 31), 2D (n = 29), and Article (n = 27) formats. Collected data were analysed using statistical inference.

Results indicate that immersive journalism can elicit a positive attitudinal change in users, unlike an Article, with mobile VR having a more prominent effect than a 2D screen. Furthermore, this change is more strongly affected by users' higher Involvement in the content.

These findings are relevant for grasping the distinct effects novel and recently popularized technologies and media have on attitudinal change, as well as inform the current debate on the value of VR as “empathy machines”.