This study examines the influences of milling-induced surface topography and residual stresses on the fretting fatigue behaviour of high-strength steel 34CrNiMo6 + QT (AISI 4340) under flat–flat contact conditions. Various milling parameters (feed rate, cutting depth, and tool configuration) were systematically varied to characterize their influence on surface roughness and residual stress states, which ranged from tensile to compressive depending on tool stiffness and cutting conditions. Derived milling configurations were subsequently employed to produce specimens for plain fatigue and fretting fatigue experiments under actively controlled slip amplitude and defined contact pressure. The resulting S–N curves revealed a 78% reduction in fretting fatigue strength compared to plain fatigue attributable to tribological damage mechanisms. While lower surface roughness promotes the crack growth in the inclined section, compressive residual stresses appear to moderately improve the fretting fatigue limit by enhancing crack arrest, as indicated by marker load tests. Moreover, the breadth of the surface power spectrum, expressed by the Nayak parameter, exerts only a minor influence on the normalized number of load cycles. Instead, the fretting fatigue life is primarily affected by adhesive wear and mechanical interlocking influencing the crack initiation. Adhesion formation is largely governed by macroscopic surface waviness and mostly independent of residual stresses. These results indicate that the residual stresses mainly influence the fretting fatigue limit through crack arrest while the surface topography modifies the level and depth affected by contact stresses and primarily governs the specimen lifetime in the HCF regime.
This article contributes to IR scholarship on the domestic politicisation of international affairs, focusing on transnational actors and mechanisms through which international issues can become politicised domestically. It conceptualises transnational politicisation as cross-boundary processes that draw international issues into the realm of domestic political choice and contestation. The analysis zooms in on diaspora groups as an exemplary case of such transnational politicisation, given their unique position in the transnational space. We argue that diasporas play a powerful role in the transnational politicisation of bilateral issues between homeland and hostland within host country domestic politics, either as politicising agents or conduits of politicisation attempts by home or host country political actors. Transnational processes of politicisation can generate intergovernmental friction, reducing the scope for bilateral cooperation, if they lead to widespread domestic politicisation in the host countries, raising identity-related and sovereignty concerns. The article presents two heuristic case studies on the Turkish diaspora in Germany, focusing on the 2016 ‘Armenia resolution’ of the German Bundestag and the 2017/2018 cycle of German and Turkish elections. The case studies detail the diaspora actors involved, explicate the transnational mechanisms through which bilateral issues become politicised in German domestic politics, and discuss consequences for German-Turkish relations.
Focusing on five forms of generosity (i.e., financial generosity, material generosity, volunteering time and effort, sharing knowledge and advice, and lending or sharing possession), this study examined the relationship between generosity and happiness among urban Malays in Kuala Lumpur. Drawing from a sample of N = 942 Malays with varied household income levels, regression analysis, supplemented by White-heteroskedasticity correction and bootstrapped standard errors, and robust regression using Huber’s M-estimator were performed. The results show that both generosity and household income are positively associated with happiness, with generosity showing a larger standardized coefficient. Financial generosity (β = 0.20) and lending or sharing possessions (β = 0.19) show the strongest associations among the generosity domains. Financial generosity may offer greater flexibility and more immediate benefits, while lending or sharing possessions may enhance happiness through everyday reciprocity and social connectedness. Material generosity, volunteering time and effort, and sharing knowledge or advice show weaker associations with happiness, compared to income, possibly due to time constraints in urban Malay metropolitan life or the more intangible, delayed nature of their benefits. Socioeconomic factors, including health status, social support, perceptions of corruption, and freedom to make life choices, also emerge as significant predictors of happiness, alongside household income. Freedom to make life decisions (β = 0.36) showed a larger standardized coefficient than any other factor, highlighting its central importance. This study’s findings may provide useful insights for policymakers targeting generosity-based promotion of well-being, with implications for cultural preservation and modern social arrangements in rapidly urbanised environments.
Abstract Composite materials, sacks, and geotextiles used in agricultural and landscaping applications are predominantly fabricated from petroleum-based synthetic fibers, contributing significantly to microplastic pollution throughout their lifecycle. Substituting synthetic fibers with agricultural waste-derived alternatives, such as Enset (Ensete ventricosum) fiber, offers a promising pathway to reduce petrochemical dependence while enhancing environmental sustainability. This study comprehensively investigated the physico-mechanical properties and industrial potential of Enset pseudo-stem fibers as sustainable alternatives for textile and composite manufacturing. Characterization employed gas pycnometry, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), thermogravimetric analysis (TGA), and tensile testing. FTIR analysis confirmed characteristic cellulose, hemicellulose, and lignin absorption peaks. Morphological examination revealed quasi-cylindrical fibers with diameters ranging from 70 to 265 μm (average: 156.4 μm) and diverse cross-sectional profiles including circular, bean-shaped, and serrated geometries. Density measurements yielded 1.48 g/cm³. Tensile testing demonstrated strength values of 415–900 MPa (0.28–0.61 N/tex), comparable to commercial natural fibers including flax (500–900 MPa), jute (350–700 MPa), banana (529–914 MPa), sisal (400–700 MPa), and abaca (300–1600 MPa). Tensile strength exhibited inverse relationships with gauge length and fiber diameter, consistent with weakest-link theory. Thermal analysis revealed three-stage degradation with maximum decomposition at 550 °C. The hollow tubular morphology provides superior acoustic absorption (3000–6000 Hz). Beyond technical merits, Enset fiber valorization creates sustainable income opportunities for rural farmers while mitigating environmental impacts of synthetic fiber production and agricultural waste, positioning it as a viable eco-friendly alternative for packaging, geotextiles, composites, and acoustic applications.
The growing presence and capabilities of robots and artificial intelligence (AI) make it increasingly likely that artificial entities might in the future be involved in situations requiring moral judgements. We conducted a preregistered study with two online samples (N1 = 162, N2 = 247) to investigate to what degree people are willing to let artificial agents decide in life-or-death as well as in non-lethal everyday moral dilemmas. All participants responded to eight moral scenarios (four high-stakes and four low-stakes). In life-or-death scenarios we found a clear preference for human decision-makers while in everyday low-stakes dilemmas participants’ responses indicated that either human or artificial entities might decide. Two main predictors emerged for agent preference: acceptance of AI and participants’ own moral choices in the respective scenarios. While greater acceptance of AI was in both high- and low-stakes scenarios associated with a greater willingness to let artificial agents decide, the relationship between agent preferences and participants’ own moral decisions differed between the two dilemma types. In high-stakes scenarios, a less deontological resp. more utilitarian response was associated with greater willingness to let AI or robots decide while in low-stakes dilemmas this association was reversed. Additionally, greater familiarity with AI predicted less willingness to accept artificial decision-makers, but only in high-stakes dilemmas.
