Search Results (882)

Background: Obstructive sleep apnea syndrome (OSAS) is a prevalent sleep-related breathing disorder associated with significant systemic complications and reduced quality of life. Mandibular advancement devices (MADs) represent an established alternative therapy for patients who cannot tolerate continuous positive airway pressure (CPAP). However, concerns remain regarding their potential effects on temporomandibular disorders (TMD). Materials and Methods: This retrospective exploratory study analyzed clinical records of 26 patients (mean age 55.4 ± 5.8 years) with polysomnography-confirmed OSAS and baseline TMD-related symptoms treated with a custom-made monobloc MAD. Clinical parameters were evaluated at baseline (T0) and after approximately 6 months of therapy (T1). Outcomes included apnea–hypopnea index (AHI), Epworth Sleepiness Scale (ESS), Fonseca Anamnestic Index, and health-related quality of life assessed using the SF-36 questionnaire. Repeated measures ANOVA and linear regression analyses were performed. Results: After six months of MAD therapy, a significant reduction in AHI was observed (30 ± 13.76 vs. 10.87 ± 3.9; p < 0.00001). Daytime sleepiness significantly decreased (ESS: 9.31 ± 3.53 vs. 3.38 ± 1.77; p < 0.00001). TMD symptom severity also decreased significantly according to the Fonseca Index (33.85 ± 17.74 vs. 10.00 ± 8.94; p < 0.00001). Quality of life scores improved significantly (SF-36: 41.15 ± 9.52 vs. 65.38 ± 5.82; p < 0.00001). Linear regression analysis showed no significant association between changes in AHI and changes in TMD symptoms, ESS scores, or quality of life. Conclusions: Within the limitations of this retrospective study, MAD therapy was not associated with symptom aggravation of temporomandibular disorders in patients with pre-existing TMD symptoms. Significant improvements in respiratory parameters, daytime sleepiness, and quality of life were observed after six months of therapy. Full article

Backfilling the industrial solid waste coal gangue into deep coal mine goafs for CO₂ geological sequestration is a crucial pathway to achieve the synergistic effect of pollution reduction and carbon mitigation. However, in complex deep geological environments, the chemical evolution of multiple mineral phases of coal gangue under gas–water–rock coupling effects and the carbon-controlling mechanism of residual total organic carbon (TOC) remain unclear. In this study, coal gangue from the goaf of the Xiaobaodang Coal Mine was used as the research object. Relying on a customized high-temperature and high-pressure reaction system to simulate the deep in situ environment (45 °C, 10 MPa), and combined with X-ray diffraction (XRD), total organic carbon determination, and isothermal CO₂ adsorption experiments, the geochemical mechanism by which inorganic minerals and organic residual carbon synergistically control the ultimate CO₂ adsorption potential was systematically revealed. The results show that the modification of the CO₂ adsorption potential of coal gangue by gas–water–rock reactions exhibits strong mineral phase differentiation. Systems rich in active silicates generate a large amount of secondary clay minerals through intense carbonation alteration, achieving a significant increase in micro–nano pores and absolute adsorption capacity. Systems rich in carbonates steadily release deep primary adsorption potential by widening mass transfer channels through mineral dissolution. In contrast, systems rich in primary clay minerals face an irreversible attenuation of adsorption space due to physical clogging of pore throats caused by fluid migration. Furthermore, the initial organic carbon content exerts a significant non-linear regulatory effect on the development of the micropore network. The physical adsorption sites provided by the high relative content of layered clay minerals (>41%), coupled with the interfacial enhancement effect exerted by a moderate organic carbon content (0.12~0.16%), constitute an optimal physicochemical synergistic enhancement network, which is the core geological reason for stimulating the ultimate carbon sequestration capacity of coal gangue. The results of this study not only enrich the multiphase interfacial thermodynamic theory of complex heterogeneous geological bodies but also provide solid theoretical support for the precise optimization of target areas and the long-term evaluation of carbon sinks in goaf CO₂ sequestration engineering. Full article

Hydrogen oxy-combustion with high CO₂ dilution is a key component of supercritical CO₂ (sCO₂) power cycles, such as the Allam cycle, enabling high-efficiency, near-zero-emission power generation with integrated carbon capture. However, combustion behavior under high-CO₂ conditions remains insufficiently characterized, particularly with respect to mixing and flame stability. In this study, hydrogen combustion in an O₂–CO₂ environment was investigated experimentally and numerically using a custom-designed multi-hole burner. The experiments were conducted in a 1-bar combustion chamber, while the inlet pressures of the reactants were varied between 10 and 50 bar to isolate the effect of injection conditions. Numerical simulations were performed to analyze flow, mixing, and flame structure. The results show that increasing inlet pressure leads to a more compact and localized flame, despite reduced velocity levels in the combustor due to increased reactant density. Higher inlet pressures result in increased peak temperatures but lower mean combustor temperatures, indicating more intense but spatially confined heat release. The flow field remains structurally similar across cases, while reduced radial spreading and longer residence times influence combustion behavior. Stable flame operation was achieved over a wide range of conditions, demonstrating the feasibility of hydrogen oxy-combustion under high CO₂ dilution. The combined experimental and numerical analysis provides insight into the interplay between injection conditions, mixing, and reaction rates in highly CO₂-diluted hydrogen combustion. The obtained results support the development of compact and stable direct-fired combustors for next-generation supercritical CO₂ power cycles and hydrogen-based low-emission energy systems. Full article

Natural gas transportation and distribution networks are becoming increasingly heterogeneous due to the injection of biomethane, regasified LNG, and hydrogen-enriched natural gas, requiring distributed and continuous gas-quality monitoring. This work presents an industrial Raman-based instrument for in-line measurement of natural gas and hydrogen-enriched natural gas composition and related thermodynamic properties. The system employs a 450 nm broadband laser diode, a high-throughput custom spectrometer, and a pressure-rated gas cell integrated in an ATEX-certified enclosure. Gas composition is retrieved through calibration spectra and non-linear least-squares fitting, while higher heating value is calculated according to ISO 6976. The instrument was validated over pressures from 1.5 to 17 bara and temperatures from −20 °C to 55 °C using certified representative gas mixtures. The system achieved compliance with OIML R 140 Class A requirements, with HHV errors below ±0.5% and repeatability within 0.1%, while operating without carrier gases or sample manipulation. Long-term field operations in pressure-reduction stations confirmed stable performance over twelve months. The results demonstrate that Raman spectroscopy can provide a robust, low-maintenance solution for continuous natural-gas-quality monitoring and controlled hydrogen-blending applications. Full article

Environmental supply-chain governance increasingly requires firms to trace climate accountability across buyer–supplier relationships. This study examines whether downstream customer climate pressure is associated with suppliers’ green supply-chain management and value-chain carbon accountability among Chinese listed firms. We construct an exposure-weighted customer pressure measure by combining disclosed top-customer relationships with customer climate-accountability signals, and we decompose this measure into disclosure-based and non-disclosure-based components so that symbolic and substantive accountability can be separated. We then link this measure to supplier green supply-chain indicators, value-chain carbon-disclosure components, Scope 3 disclosure, environmental investment, and reported environmental performance indicators, including air emissions, water pollutant discharge, resource consumption, and environmental tax. Using firm-year panel regressions with fixed effects, alternative pressure measures, selection corrections, and extended outcome tests, we find an association between customer climate pressure and supplier value-chain disclosure. The depth of the association is concentrated where customer carbon-disclosure visibility is observed and is not separately identified in the smaller climate-only subsample, while the value-chain interaction association is positive but imprecisely estimated there. The value-chain disclosure associations are robust to a year-stratified randomization-inference placebo test. We do not find evidence that customer pressure is associated with supplier emissions, resource use, environmental investment, or environmental tax in the available matched samples. The pattern is consistent with symbolic compliance in supply-chain carbon accountability: customer disclosure visibility maps into supplier disclosure visibility, while we do not observe parallel movement in substantive environmental outcomes. The central finding is therefore that downstream customer climate pressure is associated with what suppliers disclose rather than with what they emit, shaping supplier disclosure behavior rather than substantive emission reduction. The estimates apply to supplier-year observations with disclosed and mappable listed-customer links, which we treat as the scope condition of the study rather than as an incidental data limitation. Full article

Food waste remains a persistent sustainability challenge within independent restaurants, where operational pressures, cultural norms, and resource constraints limit systematic waste management. This study examines how an industry–academia partnership enabled the co-creation of food-waste reduction practices between hospitality students and sixteen independent restaurant operators in Wellington, New Zealand. Adopting the Participatory Action Research (PAR) approach, data were gathered through semi-structured interviews with operators and focus group discussions with hospitality students. Findings reveal that food wastage in the study units is shaped by time pressure, customer service expectations, tacit kitchen routines, and uncertainty in forecasting the demand. The study identifies three mechanisms—emotional disruption, shared reflection and experimentation—through which sustainability competencies become a part in professional identity. It offers theoretical grounded and practically actionable insights for industry–academia collaboration in resource-constrained hospitality environments. Full article

Diffusers in diffuser-augmented wind turbines (DAWTs) require high-camber airfoils operating at low Reynolds numbers (Re), and their laminar separation bubbles (LSB) significantly complicate aerodynamic predictions. No prior study has experimentally validated XFOIL, k-ω SST, and γ-Re_θ models against simultaneous lift, drag, and chord-wise pressure coefficient (Cp) measurements for the customized high-camber airfoil at Re = 68,000 (68k), 118,000 (118k), and 159,000 (159k). Lift, drag, and Cp distributions were measured experimentally. The γ-Re_θ model demonstrated superior performance, achieving a lift maximum absolute percent error of 1.6–3.4%, near-zero bias, and a coefficient of determination >0.99. It accurately captured the LSB pressure plateau at mid-chord, with mean gross-averaged Cp percent errors of 8.1% and 2.1% for upper and lower surfaces, respectively. The k-ω SST model overpredicted lift by up to +9.8% at Re = 68k and underpredicted drag by up to 66%. XFOIL is unreliable specifically for separated transitional flows at Re < 118k, but improves at Re = 159k. The experimental dataset and validated transition-sensitive RANS approach provide a foundation for low-Re airfoil and DAWT diffuser design. Future work should extend measurements below Re = 50k and above 200k, including post-stall conditions, and system-level design of DAWT. Full article

This study examines how entrepreneurial ecosystem constraints shape MSME resilience in the Jakarta–Bogor–Depok Indonesia corridor using a qualitative multiple-case design. Drawing on 20 MSME case reports across food and beverage, retail, services, and small-scale manufacturing, the study addresses two questions: (1) which ecosystem domains are the most binding constraints, and (2) how MSMEs convert ecosystem resources into resilience outcomes. The analysis shows that market pressure is the most universal constraint (20/20 cases), followed by digital-managerial support infrastructure gaps (18/20), supply chain volatility (13/20), and finance, human capital, and institutional constraints (each 12/20 cases). Cross-case evidence identifies four recurrent mechanisms: market pressure is managed through digital channel orchestration and customer engagement; capital constraints are managed through internal cash discipline and partnership-based financing; input volatility is managed through supplier diversification, local sourcing, and inventory control; and skill gaps are managed through internal training and process standardization. Building on these mechanisms, the study develops a threefold resilience typology: Adaptive Leaders, Operational Survivors, and Vulnerable Traditionalists. The main theoretical contribution is to show that MSME resilience is configurational and depends on inter-domain alignment rather than on isolated ecosystem components or entrepreneur-level grit alone. The practical contribution is a typology-based policy logic that prioritizes integrated intervention bundles, which are finance, digital capability, operations, supply chain, and managerial upgrading, over fragmented support programs. Full article

The utilization of existing telecommunication infrastructure for environmental monitoring via opportunistic sensing is rapidly advancing the field of distributed fiber optic sensing (DFOS). However, while custom-engineered sensing cables are highly characterized for hydrostatic pressure, the complex mechanical response of standard armored telecommunication networks remains largely unquantified. This study experimentally investigates the non-linear distributed pressure sensitivity of three commercial telecommunication cables (Anti-Rodent, Duct, and Microcable) across a hydrostatic pressure range of 0 to 800 PSI. Measurements were conducted using Tunable Wavelength Coherent Optical Time Domain Reflectometry (TW-COTDR) with a 20 cm spatial resolution, utilizing a stepped depressurization protocol with 15-min stabilization holds to isolate true steady-state longitudinal strain. The results reveal that protective cable armoring induces severe mechanical non-linearity. The rigid Glass Reinforced Plastic (GRP) rods of the Anti-Rodent cable acted as a structural vault at low pressures before yielding to become highly sensitive above 400 PSI. Conversely, the corrugated steel tape of the Duct cable exhibited high initial sensitivity followed by mechanical stiffening, while the unarmored Microcable maintained a linear response. These findings establish that a single linear calibration coefficient is invalid for heavily armored infrastructure, highlighting the critical need for structural characterization prior to opportunistic field deployments. Full article

Since launching the Saudi Vision 2030, it has witnessed a reflective sustainability action (SA) transformation. However, robust theoretical models investigating the multifaceted catalysts and consequences of SA in this less-developed country are still lacking in investigation. This lag prompted us to advance and validate a composite framework integrating multiple theories (e.g., institutional theory, the resource-based view (RBV), stakeholder theory, dynamic capabilities theory, and contingency theory) elucidating how policy direction (PD), market incentives (MIs), and knowledge collaboration (KC) stimulate SA adoption encompassing its environmental practices (EPs), social practices (SPs), and circular economy practices (CEPs). The investigation also probes how SA thereafter drives sustainable performance outcomes. A machine-learning approach using the PLS-SEM facility was applied based on 400 questionnaires targeted at managerial positions working in the tourism and hospitality segment based in Saudi Arabia. The findings reveal that all the proposed relationships were supported, providing strong empirical support for the proposed sustainability framework in the Saudi tourism and hospitality context. Institutional pressure and the governance/regulatory environment also showed a significant impact on environmental practices, sustainable performance, and circular economy practices, whereas cost efficiency, competitive advantage, customer demand for sustainability, and knowledge collaboration also demonstrated a positive impact on sustainability actions and outcomes. Furthermore, robust analysis shows that larger firms respond more strongly to MI in terms of cost efficiency, competitive advantage, and customer demand, while CEP produces a modest improvement in hotels compared with restaurants. Our model develops a theoretical synthesis beyond fragmented views. It also provides tangible guidance for industry leaders and regulators in driving strategic alignment with the SDGs and in developing a resilient, situational model that promotes regenerative tourism in high-growth, vulnerable destinations. Full article

Resource dependence pressure helps explain why some manufacturing firms remain tied to resource-based business paths even when green transformation is needed. Existing resource curse studies have mainly examined countries, regions, and resource-based cities, while less is known about how resource dependence works inside firms. We examine whether resource dependence pressure is associated with green innovation performance among Chinese manufacturing firms. Resource dependence pressure is defined as firm-level pressure arising from resource-linked customers and markets, resource-oriented suppliers and production chains, local policy/project opportunities, and inherited operating routines. Drawing on resource dependence theory, organizational inertia theory, and the digital dynamic capability perspective, we propose that organizational inertia mediates the relationship between resource dependence pressure and green innovation performance, while digital capability weakens the association between resource dependence pressure and organizational inertia. Survey data from 504 Chinese manufacturing firms are analyzed using PLS-SEM, with multi-group analysis comparing firms in resource-based cities and non-resource-based cities. The results show that resource dependence pressure is negatively associated with green innovation performance and positively associated with organizational inertia. Organizational inertia mediates this relationship. Digital capability weakens the resource dependence pressure-organizational inertia relationship, and this moderating pattern is stronger among firms in resource-based cities. The study extends resource curse research to the firm level and shows how digital capability is linked to weaker resource-induced organizational lock-in. Full article

Balancing wetland conservation with food security is a critical challenge for developing countries. This study compares land use change and its impacts on soil properties in two hydrologically distinct wetlands: the rain-fed Jinchuan Peatland in China and the flood-fed Kilombero Valley Floodplain (KVFP) in Tanzania. Using remote sensing data from 1990 to 2018 and soil physicochemical analysis, we found divergent reclamation trajectories. Wetland conversion has slowed in China but accelerated in Tanzania’s KVFP due to population pressure. Our results reveal a fundamental mechanism: rain-fed wetlands, lacking external nutrient replenishment, experience significantly greater soil degradation after conversion compared to flood-fed wetlands, which benefit from continued alluvial sediment inputs. Both sites showed post-conversion declines in soil moisture, total organic carbon (TOC), and total nitrogen (TN), alongside increased pH and bulk density. However, soil fertility loss was markedly more severe in Jinchuan than in KVFP. This disparity is attributed to the inability of rain-fed systems to replenish nutrients externally, whereas flood-fed KVFP benefits from continued alluvial sediment inputs. Our findings elucidate a key mechanism: flood-fed wetlands possess a natural resilience to agricultural disturbance through hydrological replenishment, making them potentially more suitable for sustainable utilization in food-insecure nations. Consequently, we propose that wetland management policies must be customized based on water source type and national development context, advocating for the targeted, science-based utilization of flood-fed wetlands as a strategic approach to reconcile food production with ecosystem preservation in regions like Tanzania. Full article

The separation of synthesised ammonia from unreacted nitrogen and hydrogen is a crucial step in producing high-purity ammonia and enabling the efficient recycling of unreacted gases in the ammonia synthesis process. The separation of ammonia from nitrogen and hydrogen was studied using zeolite 13X. Experiments were performed using a custom-designed experimental apparatus developed specifically for this study. Adsorption isotherm data for ammonia, hydrogen, and nitrogen were obtained over a temperature range of 293–313 K and pressures up to 5 bar. The results show that the adsorption capacity of zeolite 13X for ammonia is significantly higher than for nitrogen and hydrogen. This indicates a substantially stronger affinity toward ammonia molecules, enabling highly selective adsorption. The experimental isotherm data were successfully fitted using the Sips model, which accurately described the adsorption behaviour of the gases and showed good agreement with the measured data. The adsorption performance of zeolite 13X was further evaluated through a series of dynamic breakthrough experiments under varying pressures and gas compositions. The results confirmed the high selectivity of zeolite 13X for ammonia, with negligible adsorption of nitrogen and hydrogen. Ammonia breakthrough time was found to increase with system pressure, reflecting enhanced adsorption capacity. These findings highlight zeolite 13X as an effective and reusable adsorbent for selective ammonia separation in multi-component gas streams, with promising potential for industrial applications. Full article

The conducted study examines the environmental impacts of logistics sector operations and possible solutions to reduce them. The main aim is to balance the stability of sustainability principles across economic, social, and environmental indicators by applying green methods. Logistics warehouse operations are also important, because they can also have negative impacts, but this study focuses on environmental pressures. Logistics firms choose to implement green sustainable methods because their major sustainability aim is the protection of the environment. Moreover, by achieving this vision, logistics companies can create better brand image and attract more customers and suppliers. This study included a survey conducted among various professionals to obtain a deep understanding of the topic, with the findings being visualised in charts to improve understanding and generate an interest for this area of study; a table illustration is also provided to clearly present the factors contributing to the environmental footprint of logistics firms and solutions to mitigate them. According to the results given in this article, it can be stated that the modern world shows great interest in the topic of sustainability and takes into strict consideration green methods in order to achieve sustainable operations efficiently. Full article

To investigate the bank protection performance of polyvinyl chloride (PVC) sheet piles subjected to water level fluctuations, this study systematically examined the mechanical responses of PVC sheet piles with varying stiffnesses and their influence mechanisms on bank slope stability using a custom-designed water level control device. The variation laws of the pile top displacement, lateral earth pressure, bank slope moisture content, and slope top settlement were revealed. Furthermore, the stability of the PVC sheet pile-protected bank slope was analyzed through numerical simulations. The results indicate that the initiation time of the slope top settlement is significantly delayed by the implementation of sheet piles with different stiffnesses. The maximum settlement decreases as the sheet pile stiffness increases; notably, the 12 mm thick sheet pile reduces the ultimate settlement by 52.0%. Correspondingly, the peak horizontal displacement at the pile top decreases from 7.8 mm to 3.4 mm with the increase in stiffness. In addition, the 4 mm thick sheet pile can release soil stress through yielding deformation, resulting in a nonlinear variation in lateral earth pressure characterized by an “initial increase–brief decrease–subsequent increase” pattern. Conversely, the deformation of the 12 mm thick sheet pile is restricted, impeding stress release and causing the lateral earth pressure to increase continuously, reaching 13.3 kPa. Finally, numerical simulations further reveal that a faster water level rising rate leads to a more significant improvement in bank slope stability, yielding a maximum safety factor of 7.088, while the maximum horizontal displacement decreases from 468.2 mm during a slow rise to 124.1 mm during a rapid rise. Full article