The present study is motivated by the global transition toward carbon neutrality, which requires replacing fossil fuels with clean energy carriers. The study investigates the combined effects of hydrogen enrichment, swirl ratio (SR), and diesel injection timing (DIT) using three-dimensional computational simulations. A naturally aspirated single-cylinder engine (910 rpm, 4.05 bar BMEP) operating on 25% diesel and 75% natural gas was first analyzed to establish baseline conditions by varying DIT from 10 degrees to 70 degrees bTDC. Based on the optimized DIT, hydrogen substitution (0-40%, replacing NG) was examined based on the constant energy principle. Hydrogen enrichment increases ITE by 22.3% and reduced ISFC by 40.4%, while nearly eliminating soot and significantly reducing CO and UHC emissions. However, NO x emissions increased due to elevated in-cylinder temperatures and advanced combustion phasing. To mitigate this, parametric optimization of SR (0.5-2.0) and DIT (5 degrees -20 degrees bTDC) was conducted at 40% hydrogen share. The combination of high SR (2.0) and DIT of 20 degrees bTDC reduced NO x by 30.8% and soot by 18.8%, while improving thermal efficiency, indicating enhanced premixing and reactivity-controlled combustion behaviour consistent with the RCCI mode of operation.
Near-dry electrical discharge machining (NDEDM) has become a sustainable alternative to traditional electrical discharge machining (EDM) because of its superior flushing efficiency, reduced dielectric-fluid use, thinner recast layer thickness (RLT), and improved machining performance. These benefits are important for Nitinol (Ni–Ti shape memory alloy), which is used in biomedical implants. However, the dielectric medium and electrode influence elemental migration and recast-layer characteristics, which affect corrosion and wear resistance. Despite interest in NDEDM, the effects of NDEDM-induced modifications on corrosion behavior in simulated body fluid (SBF) and tribological performance remain insufficiently understood. This study evaluated wet EDM and NDEDM with multiphase dielectrics (EDM oil, air + oil mist, air + deionized water mist) and brass, copper, and titanium electrodes to assess Nitinol’s integrity, SBF corrosion behaviour, and wear. The findings showed that air + EDM oil mist produced thinner, uniform recast layers with higher oxygen (3.27–4.82 wt%), promoting TiO₂ passive layers, whereas wet EDM creates thicker, carbon-rich, irregular surfaces. Copper–air + EDM oil achieved the lowest roughness Ra = 0.51 µm). Electrochemical tests showed a corrosion rate reduction from 58.64 µm/year to 14.15 µm/year. Wear assessments revealed resistance with EDM oil, especially titanium–EDM oil, yielding a wear rate of 0.01578 mm³ /min and a 0.83 friction coefficient. These results link recast-layer characteristics, chemistry, corrosion, and wear, informing EDM optimization for Nitinol biomedical applications.
Abstract The current study introduces a novel cross-linked biopolymer (BP) blend of chitosan and sodium alginate at concentrations of 1%, 2%, and 4% for immobilizing Cr 6+ and Cd 2+ (at concentrations of 300 and 500 mg/kg) in clayey soil. This research aims to develop a biopolymer blended clay liner for landfills and contaminated sites by enhancing sorption while preserving geotechnical integrity. The objective includes evaluating BP's efficacy in heavy-metal immobilization and enhanced geotechnical performance through pH, electrical conductivity, 1-D consolidation, and sorption tests on control (metal-spiked) and BP-treated soils prepared at 70% maximum water-holding capacity. Results show a reduction in void ratio and compressibility, predominantly in the 500-mg/kg Cr 6+ -spiked soil, primarily due to the adsorption and surface complexation of the predominant aqueous hydrogen chromate ( HCrO 4 4 − ) species under acidic conditions, resulting in enhanced particle aggregation and pore volume reduction. Up to 2% BP, all samples meet the linear hydraulic conductivity criteria (≤10 −7 cm/s) and exhibit an increase in sorption capacity. However, 4% BP slightly increases compressibility and conductivity and reduces sorption due to uneven mixing and metal-induced flow paths. Fourier transform infrared spectroscopy confirmed coordination bonds via adsorption and metal chelation in the BP matrix. Optimally, 1% and 2% BP balances superior sorption with geotechnical stability, offering an eco-friendly innovation over conventional stabilizers for heavy-metal containment in clayey soil.
PurposeThe hospitality industry increasingly regards the integration of digital technology as vital for improving operational efficiency, sustainability and organisational resilience. This study examines the influence of digital maturity (DM) on essential hotel practices - Environmental Management (EMP), Community-Oriented Practices (COP), Employee-Oriented Practices (EOP) and Operational Excellence (OE) - and their resulting effects on hotel sustainability and resilience.Design/methodology/approachThe research employs Partial Least Squares Structural Equation Modelling (PLS-SEM) to illustrate that digital maturity positively affects these behaviours, subsequently improving sustainability and resilience outcomes.FindingsThe findings indicate that although digital maturity promotes sustainability via COP and EOP, its effect on resilience is influenced by practices centred on employees and the community.Originality/valueThis research underscores the strategic significance of digital transformation in fostering long-term success for hotels through operational, optimisation and promoting sustainable and resilient practices.
This study will investigate the impact of interlayer and cooling conditions on the microstructure, and fatigue characteristics of AA6061-T6 aluminum alloy welds produced using Friction Stir Welding (FSW). The introduction of a brass interlayer between the weld plates promotes the formation of intermetallic compounds and induces grain refinement, thereby enhancing the mechanical properties of the welds. To further improve performance, water-assisted cooling was employed as a rapid cooling approach during welding, and its effects on microstructure, intermetallic phase formation, and mechanical behavior were thoroughly assessed. Water cooling reduced the stir zone size, resulting in rapid heat extraction. EBSD and texture analysis revealed refined grains with a dominant {001}{111} orientation under water-cooled conditions. EDAX mapping confirmed reduced diffusion of Zn and Cu in water-cooled welds, which limited the formation of brittle intermetallic compounds such as Al2Cu and Al4Cu9. The water-cooled welds with an interlayer exhibited superior tensile strength and hardness, primarily due to enhanced grain refinement and the suppression of intermetallic embrittlement. Fatigue analysis demonstrated significantly improved fatigue life for the interlayer-integrated water-cooled welds, compared to natural-cooled welds. Fractographic examinations revealed ductile failure in water-cooled interlayered welds, whereas naturally cooled welds showed premature failure accompanied by voids and brittle fracture modes.
