Search Results (20,860)

Laser–MIG hybrid welding is increasingly used in shipbuilding for medium-thick steel plates, where assembly-induced gaps and misalignment often compromise weld quality. In this study, a three-dimensional transient numerical model is established to simulate the molten pool dynamics during full-penetration laser–MIG hybrid welding of 10CrNiCu steel under varying gaps and misalignment conditions. The model incorporates coupled heat transfer, fluid flow, keyhole behavior, and droplet transfer and is validated against experimental weld profiles. The simulation results reveal that increasing gap size broadens the heat distribution, reduces keyhole depth, and decreases the bridging capacity of the filler metal. Larger misalignment enhances the step effect, promotes gravity-driven downward flow of liquid metal, and increases keyhole instability and porosity risk. The adaptability to assembly errors is further assessed. As welding current increases, the gap tolerance slightly improves from 1.61 mm to 1.65 mm, whereas the misalignment tolerance markedly decreases from 3.00 mm to 1.82 mm due to the earlier onset of porosity defects. These findings provide quantitative guidance for optimizing welding parameters to accommodate realistic assembly variations in marine steel fabrication. Full article

To optimize the tribological properties of a mechanical transmission skateboard, rectangular micro/nanogrid structures of different sizes are studied. The reciprocating sliding tests are carried out under friction and wear. The results show that with an increase in the lengths from 330 to 484 μm and widths from 247 to 363 μm of the grid structures, the friction coefficients and wear rates first decrease and then increase. This results in the smallest friction coefficient and wear rate of the TCSC-G-4 with 440 μm length and 330 μm width. This is because the micro/nanogrid structures provide the lubricant SnAgCu-CaF₂ (SC), which is sufficient for lubrication film formation. During wear, SnAgCu deformation and CaF₂ rolling lead to mixed lubrication that is dominated by the rolling, sliding and roller–sliding, enhancing the plastic flow of the lubrication film for surface repair. This is of great significance for guiding the bionic tribological designs of the skateboard. Full article

Solar thermal calorimeters serve as foundational reference instruments for quantifying absorbed thermal power, evaluating optical-to-thermal conversion efficiency, and validating computational models in concentrated solar thermal (CST) research. This review synthesizes recent numerical, thermo-hydraulic, and experimental advancements, evaluating the evolution from basic single-tube configurations to high-confinement cavity calorimeters (achieving apparent absorptances $>0.99$) and flat-plate architecture enhanced with impinging jets and internal fin arrays. The selection of working fluids is examined; water accounts for approximately $87\%$ of reported implementations due to low property uncertainty, whereas synthetic oils and gaseous coolants expand operating temperature ranges at the expense of thermochemical degradation and parasitic pumping penalties. Furthermore, critical thermo-hydraulic challenges induced by extreme non-uniform heat fluxes are identified, including structural thermal bowing, parallel-channel flow maldistribution, recirculation traps, and buoyancy-driven instabilities occurring at Richardson numbers $\mathrm{Ri}\gg 10$. Metrological constraints related to solar reflection interference in non-contact thermometry and calibration drift in photometric target arrays are also critically addressed. Finally, key strategic research directions are outlined, emphasizing high-temperature advanced materials, active flow equalization, real-time multi-physics digital twins, and standardized dynamic testing metrology. Full article

Background/Objectives: Severe posterior mandibular atrophy presents anatomical challenges for implant rehabilitation because of reduced residual bone volume and the close relationship between the mental foramen, its anatomical variations, and the surrounding alveolar bone. Among these variations, the anterior loop may further influence the available lingual bone adjacent to the mental foramen. Despite the clinical importance of this region, quantitative three-dimensional anatomical information regarding lingual bone availability remains limited. Therefore, the aim of this retrospective cone-beam computed tomography (CBCT)-based study was to quantitatively evaluate the availability of lingual bone adjacent to the mental foramen in posterior atrophied mandibles and to assess the influence of the anterior loop on these anatomical dimensions, thereby providing quantitative anatomical information about this region. Methods: In a retrospective CBCT-based anatomical study, 110 CBCT scans of adult patients with atrophied mandibles were analyzed using standardized cross-sectional views perpendicular to the dental arch; linear measurements were obtained from the lingual cortical plate to the mesial (Point A), middle (Point B), and distal (Point C) borders of the mental foramen. The presence of the anterior loop was recorded. Descriptive statistics and independent-samples t-tests were performed to compare measurements between loop and no-loop groups (α = 0.05). Results: The mean measurements of the lingual bone were 7.22 ± 1.65 mm at Point A, 6.18 ± 1.55 mm at Point B, and 4.82 ± 1.38 mm at Point C, showing a gradual decrease from mesial to distal. An anterior loop was found in 26.4% of the cases. Significantly thinner dimensions of the lingual bone were observed with an anterior loop at all three measurement points (p < 0.01). Conclusions: The present CBCT-based anatomical study measured the amount of lingual bone available adjacent to the mental foramen in posterior atrophied mandibles and observed a significant correlation between the presence of an anterior loop and reduced lingual bone dimensions. These findings add to the knowledge of the anatomy of this area and could serve as the basis for future clinical studies to investigate the potential for a mental foramen bypass concept. Full article

In the hyper-arid climate of Riyadh, Saudi Arabia, the building envelope is a critical determinant of energy demand and occupant comfort. This paper reports an experiential-learning experiment in which undergraduate architectural-engineering students applied building performance simulation (BPS) as a generative design instrument rather than a post-design audit tool to their own real capstone building, a 6581 m² mixed-use development. Using Sefaira (EnergyPlus/Radiance engines), they iteratively diagnosed, tested, and refined envelope decisions against the prescriptive thresholds of the Saudi Building Code (SBC 601). A baseline analysis revealed a high Energy Use Intensity (EUI) of 139 kWh/m²·yr, driven primarily by solar heat gains and an “overlit” floor plate that exceeded Annual Sunlight Exposure (ASE) thresholds. Students then implemented passive interventions—improved glazing U-value (0.50 W/m²·K), reduced Solar Heat Gain Coefficient (SHGC 0.20), and external shading fins. These produced a 6.95% EUI reduction (139→130 kWh/m²·yr) and a 17.24% fall in cooling energy. The energy outcomes are consistent with established findings for hot-arid envelopes and are therefore treated here not as the novelty but as the technical evidence the students generated. Daylighting analysis confirmed improved distribution and reduced glare risk, although ASE remained above the LEED v4 threshold. The contribution is pedagogical: the study documents a replicable framework through which a design studio develops students’ technical competence in performance-driven envelope design, evidenced by their progression from uninformed parameter selection to code-referenced design reasoning and by the difficulties and trade-offs they encountered. Full article

Dental rehabilitation of fibula free flap mandibular reconstructions can be limited by the reduced vertical bone height available for implant placement. This study evaluated the biomechanical influence of ultra-short, extra-short, and conventional implants in a reconstructed fibula. Methods: A patient-specific finite element model of a fibula-reconstructed mandible was developed. Three splinted implants with a diameter of 4 mm and lengths of 3, 5, or 12 mm were compared under postoperative unilateral molar loading. Von Mises stresses were evaluated in the implants, fibula, residual mandible, and fixation plates, while equivalent elastic strain was assessed in peri-implant bone. Results: Implant length had minimal influence on implant stress (36.8–37.1 MPa) and fibular cortical bone stress (52.5–53.1 MPa). The 5 mm implants produced the lowest peri-implant strains and the lowest posterior reconstruction-plate stress (71.3 MPa), compared with 75.4 MPa for 3 mm and 107.8 MPa for 12 mm implants. The 12 mm implants generated greater apical strain concentrations, exceeding the adopted mechanobiological threshold around the central and mesial implants. Conclusions: Within the limitations of this study and under the simulated immediate postoperative loading condition, shorter implants, particularly 5 mm implants, showed a favorable biomechanical response. Full article

The developing chemical industry increasingly emphasizes environmentally friendly products. As consumers’ environmental awareness grows, so do their expectations of cleaning products, which must not only maintain high cleaning efficacy but also be safe for both humans and the environment. However, previous studies have not evaluated biodegradability potential alongside chemical integrity, preservation efficacy, packaging stability, interfacial performance, and consumer acceptance within a unified framework. The aim of this study was to analyze two proprietary formulations of car shampoo concentrates. Both products were assessed for basic physicochemical parameters and analyzed using chromatographic techniques, which revealed no presence of by-products or harmful substances. Subsequently, compatibility tests were conducted with PET bottles, monitoring mass loss, pH, viscosity, turbidity, and fluorescent polymer content over several months. In addition, surface tension analysis was performed using the Wilhelmy plate method, and biodegradability tests were conducted in accordance with OECD 301B in an aquatic environment, yielding 100% potential biodegradation results for both shampoos. Finally, a consumer analysis was also carried out, based on which a formulation with more favorable performance properties was selected. The integrated results provide system-level evidence that environmental performance can coexist with formulation robustness and consumer usability. Full article

Brazed-plate heat exchangers (BPHEs) are widely used as recuperators in organic Rankine cycle (ORC) systems, but their corrugated passages make full-scale Computational Fluid Dynamics (CFD) simulations prohibitively expensive, limiting the use of CFD for performance prediction and for deriving design-oriented heat-transfer correlations. This work presents a validated domain-reduced CFD methodology for a BPHE recuperator operating with R134a. The computational domain is reduced to a single exchange unit (one vapor and one liquid corrugated channel separated by one heat-transfer plate), further downscaled by truncating the plate length to the fully developed corrugated region, exploiting longitudinal symmetry, and approximating the corrugation profile with a trapezoidal shape; the resulting mesh (≈4.5 × 10⁶ cells) is approximately 44.5 times smaller than the estimated 2 × 10⁸-cell full-stack mesh. Five steady operating points from a micro-scale ORC test rig (mass-flow rate 0.08–0.22 kg/s, Re ≈ 500–18,500) are used for validation by mapping experimental data to the reduced domain through an ε–NTU formulation. CFD predictions of hot- and cold-side temperature changes agree within 1–10% of the reference values. Building on this validated model, single-phase Nusselt-number correlations are proposed, valid over 500 < Re < 1400 for the liquid phase and 6000 < Re < 18,500 for the vapor phase. The proposed method and results support preliminary, geometry- and model-specific assessment of BPHE recuperators; broader transferability requires additional geometries, operating points and model-form validation. Full article

Partial discharge (PD) detection is a crucial means for the early warning of incipient insulation defects in arresters. However, under strong electromagnetic interference and background noise, PD signals are prone to distortion, making it difficult to accurately determine the pulse onset front and thus severely degrading the accuracy of time-delay estimation. To address the difficulty of time-delay estimation under low signal-to-noise ratio (SNR) and multi-channel aliasing conditions, this paper proposes a method for arrester PD detection and high-precision time-delay estimation based on joint denoising and improved cross-correlation. First, a joint denoising strategy that integrates singular value decomposition (SVD), variational mode decomposition adaptively optimized by the sparrow search algorithm (SSA-VMD), and the Teager energy operator (TEO) is constructed. This strategy suppresses white noise and periodic narrowband interference while effectively extracting the oscillatory onset characteristics of PD pulses. Second, an enhanced time-delay estimation method based on HB-weighted generalized quadratic cross-correlation is introduced. By employing the dual mechanisms of HB frequency-domain weighting and amplitude weighting to sharpen the correlation peak, the estimation robustness under low SNR is improved. Simulation results show that the proposed method attains an accuracy of 99.9911%, significantly outperforming conventional cross-correlation, PHAT-SCOT, and NLMS methods. Finally, experiments are conducted on a needle-plate discharge platform. In multiple comparative experiments with different spatial distance differences (ranging from <30 cm to >50 cm), the maximum relative error is kept within 0.6%, verifying the reliability and accuracy of the proposed algorithm under controlled laboratory conditions. This method can provide a new approach for online monitoring and accurate fault location of arresters in power systems. Full article

Aqueous zinc-ion batteries are promising candidates for large-scale energy storage as high-safety, low-cost, and abundant zinc resources. Compared with conventional zinc foil, zinc powder (Zn-P) anodes display controllable capacity by regulating zinc powder loading, electrode thickness and pore structure, providing opportunities to improve zinc utilization, reduce costs and enhance manufacturing compatibility. However, Zn-P anodes are dynamic particle-composite electrodes in which reaction interfaces, pore channels, particle contacts, and electronic networks continuously evolve during cycling and storage. Their electrochemical behavior therefore reflects coupled effects of Zn²⁺ plating/stripping, hydrogen evolution, corrosion, by-product-induced pore blockage, stress evolution, contact loss, and calendar aging. This review focuses on the structural characteristics, failure mechanisms, interfacial reaction regulation, electrode engineering, and practical evaluation of zinc powder anodes. It subsequently analyzes the application boundaries of zincophilic metals, carbon materials, MXene, Meta–Organic Frameworks/Covalent Organic Frameworks (MOFs/COFs), artificial interphases, electrolyte additives, slurry engineering, current collectors, and manufacturing strategies. Then, it points out their mechanisms for regulating reaction selectivity, ion/electron transport, and structural stability. Further, the practical evaluation criteria are given, including Zn loading, the negative/positive capacity ratio (N/P ratio), Zn utilization, electrolyte dosage, calendar life and pouches/large-scale cells under limited zinc conditions. Overall, Zn-P anode development should focus on interfacial reaction selectivity, powder structure, electrode manufacturing and limited-zinc evaluation. Full article

Background: Candida albicans can adapt to inhibition of the classical mitochondrial respiratory chain by activating an alternative oxidase (AOX)-dependent pathway, whereas Candida glabrata lacks detectable AOX-mediated respiration under the conditions tested. Identifying compounds that selectively inhibit this alternative pathway may provide new therapeutic strategies against fungal pathogens. Methodology: The antifungal activity of 5-Nitro-1,10-phenanthroline (5-Nitro-Phen) and 1,10-phenanthroline (Phen) was evaluated against C. albicans and Candida glabrata using a diffusion plate assay. Oxygen consumption was measured in intact cells before and after cyanide inhibition of Complex IV, and cyanide-resistant respiration was assessed using salicylhydroxamic acid (SHAM). Metal-chelating activity was evaluated relative to EDTA. Molecular docking was performed using SwissDock, ReverseDock, and PrankDock to predict interactions with AOX1. Results: Both compounds showed greater antifungal activity against C. albicans than C. glabrata, with C. glabrata inhibited only above 350 μM. In C. albicans, cyanide revealed a SHAM-sensitive, AOX-dependent respiratory component that was selectively inhibited by Phen and 5-Nitro-Phen. In contrast, C. glabrata showed no detectable cyanide-resistant or AOX-dependent respiration. Although Phen exhibited greater metal-chelating activity (43% relative to EDTA), both compounds showed similar AOX inhibitory potency (IC₅₀ = 2.7 and 2.9 μM, respectively). Docking predicted favorable binding to AOX1 (−7.39 to −8.395 kcal/mol), involving hydrophobic residues including Phe247, Phe251, Val254, and Phe265. Conclusion: Phen and 5-Nitro-Phen inhibit AOX-dependent respiration in C. albicans, supporting AOX as a promising antifungal target and phenanthroline derivatives as potential scaffolds for AOX-directed inhibitor development. Full article

Paraprobiotics offer safer alternatives to live probiotics without requiring cell viability. Here, heat-inactivated bacterial preparations (paraprobiotics) were produced from Lacticaseibacillus paracasei subsp. paracasei 431 (L. casei 431) using thermal treatments (65–121 °C). No viable colonies were detected by conventional plating in any treatment, and flow cytometry indicated that more than 96% of cells were membrane-compromised or dead. The most favorable condition (65 °C, 60 min) was identified using a TOPSIS multi-criteria ranking approach integrating loss of culturability with antimicrobial activity against Enterococcus faecalis and Escherichia coli with inactivation efficiency. This paraprobiotic and the corresponding probiotic were subjected to in vitro gastrointestinal digestion and colonic fermentation, followed by short-chain fatty acid (SCFA) and 16S rRNA-based gut microbiota analysis. The fecal inoculum was pooled from five healthy donors and used to run three replicate fermentation vessels per group. Both probiotic and paraprobiotic supplementation significantly increased acetate, butyrate, and total SCFA concentrations compared with the control, and propionate and valerate concentrations were also significantly higher in the paraprobiotic group than in the control. Both interventions increased Chao1 richness and Simpson diversity (p < 0.05), although Shannon diversity did not differ significantly, and induced significant shifts in beta diversity, alongside marked enrichment of butyrate- and SCFA-producing taxa such as Roseburia, Anaerostipes, and Akkermansia muciniphila. However, not all observed microbial changes were unequivocally beneficial; increases in Bilophila wadsworthia and Collinsella aerofaciens warrant cautious interpretation given their context-dependent associations with host health. Spearman correlation analysis identified positive associations between enriched taxa and SCFA concentrations, which should be interpreted as exploratory rather than evidence of causal metabolic cross-feeding. Under the conditions of this in vitro fermentation model, no statistically significant differences were detected between the viable and heat-inactivated preparations for most measured outcomes, indicating that thermal inactivation did not markedly diminish the capacity of L. casei 431 to influence gut microbial composition and short-chain fatty acid production. The multi-criteria selection strategy offers a practical approach for optimizing paraprobiotic production for functional food applications. Full article

Many red algal species described solely from morphology have historically been assigned to inappropriate genera because of superficial morphological similarity. Laurencia chilensis, originally described for specimens from Chile, has long been recognized as the only representative of Laurencia in Chile, but its systematic position is still understudied. We examined morphology of syntype material and specimens collected in the present study and analyzed rbcL sequences from our collections. One syntype specimen (De Toni herbarium no. 63) is here designated as the lectotype of L. chilensis. Laurencia chilensis specimens possess five pericentral cells per axial segment and plate-like spermatangial branches with sterile marginal cells, typical of the tribe Chondrieae. The rbcL sequences we obtained were identical and recovered the Chilean specimens as a strongly supported, distinct lineage from Chondria and other genera within the Chondrieae. Accordingly, we propose Austrochondria chilensis gen. et comb. nov. This study resolves the long-standing taxonomic position of this Chilean endemic and contributes to a more natural classification of the Chondrieae. Full article

Marine macroalgae, or seaweed, are an attractive source of novel natural products, which are in many cases not only produced by the algae themselves but also by their associated microorganisms. Therefore, the search for novel products should not only be aimed at the algae but also their symbionts. In this study, we attempted to investigate culturable microorganisms associated with nine marine macroalgal hosts collected from the Cat Ba Archipelago area (Vietnam), which is known to have significant biodiversity value. More specifically, such microorganisms were isolated by using standard plating methods with eight media under varied nutrient and salinity conditions, screened for antimicrobial activity via agar diffusion assays and MIC/MBC determination methods; those with the most remarkable activities were identified based on their morphology, 16S rRNA gene sequences, and housekeeping gene rpoB sequences if necessary. We obtained a total of 331 isolates, among which 15 bacterial isolates exhibited detectable antimicrobial activity against at least one of the four test microorganisms. The isolates displaying notable antimicrobial activities were affiliated predominantly with Bacillus species, together with representatives of Virgibacillus, Exiguobacterium, Alcaligenes and Serratia. Interestingly, almost all of the associations of those bacteria with the seaweed hosts have not yet been reported. Among those isolates, Bacillus velezensis S.002, found to be associated with the red alga host Gelidium crinale for the first time, exhibited the most remarkable antibacterial activity, and the ethylacetate extract of its culture showed the lowest MIC values against both B. subtilis and X. oryzae. The extract was therefore fractionated and the fraction exhibiting pronounced antibacterial activities was analyzed by LC–HRMS to putatively annotate its metabolites. The results revealed that, in addition to canonical lipopeptides, S.002 could produce several other metabolites that have merely been reported for Bacillus velezensis, including some alkaloids and a unique bioactive amino acid, which might synergistically contribute to the antimicrobial efficacy of the strain. Collectively, the results highlight Cat Ba macroalgae as promising sources of bioactive microorganisms, which in turn can be a promising source of bioactive compounds, produced as part of the host–microbe interactions. Full article