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Torsion-Induced Modification to Friedmann Equations in AdSL4 Gauged Gravity
No full textWe study the solution of the gravitational field equations in –gauged gravity, a gauge-theoretic extension of general relativity based on the algebra. In this formulation, the antisymmetric gauge field , associated with additional tensorial generators, induces space-time torsion via the relation , where denotes the contorsion 1-form. The presence of torsion modifies both the spin connection and curvature, leading to an extended set of Einstein–Cartan field equations. Focusing on spatially homogeneous and isotropic cosmological backgrounds, we derive the modified Friedmann equations which explicitly incorporate the torsional contribution. The resulting acceleration equation admits de Sitter–like solutions in which cosmic acceleration originates purely from the gauge–theoretic structure of enlarged four-dimensional space-time symmetries. Within this formulation, the dynamical components of the gauge field emerge naturally as a source of the effective cosmological constants, without the introduction of exotic matter sources. Furthermore, our analysis shows that the torsion-driven cosmological phase in –gauged gravity can reproduce an effective equation-of-state parameter , establishing a connection between space-time torsion and cosmic-string–like dynamics.</p
General off-diagonal Integrability of Metric and Nonmetric Geometric Flow and Finsler–Lagrange–Hamilton Modified Einstein Equations
No full textOver the last seventy years, many Finsler-type geometric and modified gravity theories (MGTs) have been elaborated. They have been formulated in terms of different classes of Finsler generating functions, metric and nonmetric structures, nonlinear and linear connections, and various sets of postulated fundamental geometric objects with corresponding nonholonomic dynamical or evolution equations. In several approaches, the resulting gravitational and matter field equations were not completely defined geometrically, or were developed only for restricted models. A progress report with historical remarks and a summary of new results on Finsler–Lagrange–Hamilton (FLH) geometric flow and gravity theories is presented. Such theories can be constructed in an axiomatic form on (co)tangent Lorentz bundles as nontrivial modifications of Einstein gravity. They are characterized by nonlinear dispersion relations and may encode nonassociative and noncommutative corrections from string theory, quantum effects, or other MGTs. To generate exact and physically relevant solutions of the FLH–modified Einstein equations, the anholonomic frame and connection deformation method is developed. A proof of the general integrability of such FLH geometric flows and MGTs is provided, and new classes of generic off-diagonal solutions determined by generating functions and effective sources that, in general, depend on all spacetime and (co)fiber coordinates are analyzed. In general, such off-diagonal configurations do not exhibit horizon/hypersurface duality or holographic structures and thus lie outside the Bekenstein–Hawking thermodynamic paradigm. Instead, by extending G. Perelman's entropy concept to relativistic FLH geometric flows, new classes of geometric thermodynamic variables that characterize different FLH theories and their associated solution spaces are introduce and computed
Volunteer-based disaster response during the 2023 Kahramanmaraş earthquakes: a SWOT analysis
No full textThis exploratory, qualitative case study investigates the volunteer response to the 2023 Kahramanmaraş earthquakes through a SWOT analysis, focusing on the perspectives of both volunteers and coordinators. It includes in-depth interviews and field observations involving a purposeful sample (n = 21) of participants actively engaged in volunteer coordination activities. This focused approach provides deep, contextual insights into the structured response, rather than a generalisable overview of all volunteer activities. Based on observations and interviews, the study identifies significant strengths, weaknesses, opportunities, and threats in volunteer management. MAXQDA Analytics Pro 2024 was employed to analyse data. The findings suggest various strengths, including organizability, a large number of volunteers, extensive communication, a spirit of solidarity, and representation of different professional groups. However, participants reported significant weaknesses, including a lack of training, inadequate coordination, continuity issues, and challenges in disaster area security and logistics. Participants identified essential opportunities to enhance volunteer mobilisation, particularly in relation to the young population, NGO collaborations, training opportunities, and new technologies. Nevertheless, persistent threats included uncontrolled volunteering, cultural conflicts, malicious actors, and inadequate management. Based on these results, the study proposes four strategic recommendations to strengthen voluntary disaster response systems in Türkiye and similar contexts, maximising resilience and preparedness towards possible catastrophes
Comprehensive evaluation of bismuth tungstate-deposited stainless steel in chlorine-based electrochemical degradation through by-product analysis
No full textElectrooxidation is a promising method for degrading organic pollutants in wastewater, yet the formation of harmful by-products remains a major concern for environmental and process safety. This study investigates the degradation pathways of azo and oxazine dyes using bismuth tungstate-coated stainless steel (Bi2WO6 /SS) electrodes. A central composite design was applied to optimize key process parameters, revealing that time was the most significant factor in both color and total organic carbon (TOC) removal. Under optimized conditions, complete color removal and 50 %-60 % TOC reduction were achieved. Gas chromatography-mass spectrometry analysis identified several by-products, including chlorinated organics and oxygenated compounds, indicating that active chlorine species played a dominant role in oxidation. While dye degradation was highly efficient, the formation of certain intermediates highlights the need for further toxicity assessment and process refinement to minimize secondary pollution risks. These findings emphasize the importance of by-product monitoring in electrooxidation studies and contribute to the development of safer and more effective electrochemical wastewater treatment strategies for industrial applications
Epoxidised Natural Rubber (ENR)/Wollastonite Composites for Tyre Inner Liners: A Practical Replacement for Butyl Rubber in Industrial Applications
No full textThis study aimed to develop epoxidised natural rubber (ENR)-based rubber compound formulations as an alternative to butyl rubber for tyre inner liners. The effects of different vulcanization systems, designed to achieve similar curing behavior in NR-based carcass compounds and ENR-based liner compounds, were evaluated. The selected vulcanization system was applied to other compound formulations in subsequent stages to enhance adhesion and gas barrier properties. The impact of high-aspect-ratio wollastonite on interfacial adhesion was evaluated for the first time in an ENR matrix. Additionally, the effects of varying wollastonite concentrations on the adhesion and gas barrier properties of the liner compound were examined. The compounds were assessed based on their rheological, physical, and mechanical properties, adhesion strength, gas permeability, and topographical characteristics. It was concluded that the coagent-induced vulcanization system was the most effective for co-vulcanization of NR and ENR. Additionally, adhesion and gas barrier properties were significantly enhanced by incorporating relatively low amount (5 phr) of wollastonite into ENR without notable changes in mechanical properties. The proposed formulation demonstrated adhesion between the carcass and liner compound that is approximately eight times higher than existing butyl liner applications while achieving lower gas permeability than butyl rubber
Removal of Cu(II) ions using alginate-based composite wastes from dental impression materials
No full textIn this study, alginate-based composite materials commonly used in dental impression procedures were evaluated as low-cost and sustainable adsorbents for the removal of Cu(II) ions from aqueous solutions. The effects of pH, initial Cu(II) concentration, temperature, and contact time on adsorption performance were systematically examined. Comprehensive characterization of the composites revealed interactions between Cu(II) ions and surface functional groups, while imaging and elemental analyses confirmed the porous morphology of the materials and the accumulation of copper on their surfaces, suggesting that cation exchange also contributed to metal uptake. The surface charge and PZC were determined to elucidate the pH-dependent adsorption mechanism. The equilibrium data fitted best to the Langmuir isotherm model, indicating monolayer adsorption behavior, while the pseudo-second-order kinetic model accurately described the adsorption mechanism, suggesting chemisorption. Thermodynamic parameters confirmed that the process is spontaneous and endothermic. Among the tested materials, the maximum adsorption capacities were 25.38, 25.19, and 33.00 mg/g for Plastalgin, Cavex CA37, and Kromalgin, respectively. These findings highlight the novel potential of dental alginate composites as efficient, cost-effective, and environmentally sustainable adsorbents for heavy metal removal, supported by detailed chemical and morphological analyses. Moreover, the reuse of discarded dental impression materials provides an interesting strategy for waste valorization and circular sustainability
Ignored by the boss: a moderated-mediation study of boss phubbing
No full textIntroduction: This study investigates the workplace implications of boss phubbing (BP)—a managerial behavior in which supervisors prioritize smartphone use over face-to-face interactions with employees. Drawing on Expectancy Violation Theory (EVT), Social Exchange Theory (SET), and Leader–Member Exchange (LMX), BP is conceptualized as a negative relational signal that can undermine employees’ job attitudes. Methods: A moderated mediation model was tested to examine whether satisfaction with supervision (JDI) mediates the relationship between BP and job satisfaction, and whether power distance moderates the direct and indirect effects. Survey data were collected from 412 full-time employees and analyzed using PROCESS Model 7 with bootstrapping. Results and discussion: BP significantly reduced satisfaction with supervision (JDI), which in turn fully mediated its effect on job satisfaction; the direct effect of BP on job satisfaction was not significant. Power distance did not moderate the direct path from BP to satisfaction with supervision (JDI) but did moderate the indirect effect, which was stronger for employees low in power distance. Together, these findings indicate that boss phubbing operates primarily through relational exchange processes and that cultural value orientations shape the extent to which inattentive leadership undermines employees’ job attitudes. These results contribute to the growing literature on digital workplace behaviors by clarifying how, and under what conditions, boss phubbing erodes employee outcomes
