Search Results (224)

The bubble tube of a glass curing furnace was subjected to extreme heat–flow coupling conditions for a long time due to the scouring of melt flow caused by the gas flow bubbling in a high-temperature molten glass environment at 1150 °C, resulting in severe corrosion and structural failure. This paper conducts post-service sampling analysis of an Inconel 690 bubble tube, and systematically studies its corrosion morphologies, product distribution and corrosion mechanisms. The results show that the outer wall of the bubble tube undergoes an oxidation reaction in the high-temperature molten glass to form a Cr-rich oxide layer. However, local spalling occurs under the scouring of the molten glass flow, resulting in continuous corrosion. The corrosion behavior shows obvious asymmetry. The average corrosion rate near the bubble flow side (the inner curve side, 0.118 mm/day) is significantly higher than that on the outer side (0.051 mm/day) due to the higher partial pressure of oxygen and greater flow rate of molten glass. It reveals the synergistic mechanism by which fluid scouring continuously removes the protective Cr-rich oxide scale, thereby accelerating the oxidation–erosion cycle under the heat-flow coupling effect. The results provided experimental evidence and theoretical reference for the material optimization and life prediction of bubble tubes. Full article

Background: Dimensional stability during post-curing exposure time is critical for the clinical success of 3D-printed restorations. This study evaluates how different post-curing protocols affect the accuracy of provisional crowns. Methods: Fifty-four provisional crowns (n = 27 incisors; n = 27 premolars) were fabricated using an ASIGA 3D MAX UV printer. The crowns were subjected to three post-curing durations (5, 10, and 20 min). Dimensional deviation was quantified using RMS values. Results: RMS values showed a numerical, but not statistically significant, increase with longer post-curing times (p > 0.05). The 5 min protocol yielded the lowest descriptive deviations for both tooth types. Conclusions: Although no statistically significant differences were observed, shorter post-curing times were associated with lower RMS values and may help preserve dimensional accuracy. Further studies with larger subgroup sizes are needed to confirm these trends. Full article

This study presents a coupled numerical–experimental investigation into the early-age thermo-mechanical behaviour of 3D-printed concrete (3DPC), with particular emphasis on strength development, interlayer bonding, and thermally induced cracking that govern structural buildability and performance. A coupled multiphysics modelling framework was developed in COMSOL Multiphysics by integrating hydration kinetics, maturity theory, thermo-mechanical coupling, and a cohesive-zone-based interlayer damage formulation through user-defined time-dependent constitutive relationships and domain activation functions. The model simulated the temporal evolution of temperature, stiffness, stress development, and interlayer degradation during the early-age printing process. The model simulates the temporal evolution of temperature, stiffness, and interlayer damage and was validated against experimental results from compression, interlayer bond, and fracture tests conducted under varying printing time gaps and curing temperatures. The results demonstrate that increasing interlayer deposition intervals up to 60 min leads to reductions of approximately 38% in interlayer bond strength and a significant reduction in apparent compressive strength exceeding 80% between 0 and 60 min deposition delay. It should be noted that this reduction primarily reflects interlayer-dominated failure and loss of structural continuity rather than intrinsic degradation of the bulk cementitious matrix, primarily due to hydration discontinuity, moisture loss, and progressive substrate stiffening. Elevated curing temperatures further intensify thermal gradients, resulting in higher residual stresses and increased crack susceptibility at interlayer interfaces. The numerical predictions showed good agreement with the experimental responses, with peak-force prediction errors below 5% and RMSE values of approximately 0.30–0.45 kN along the post-peak softening, confirming the reliability of the proposed modelling approach. The findings highlight the critical importance of printing continuity and thermal control in governing early-age structural performance and provide quantitative guidance for optimising process parameters in extrusion-based 3D concrete printing. Full article

Tomographic volumetric additive manufacturing (VAM) is an innovative 3D printing technology that polymerizes an entire volume of photopolymer resin simultaneously. VAM enables an increased printing speed and higher output compared with traditional stereolithography, layer-by-layer printing. We explore the operational implications of adopting VAM in an intelligent manufacturing context by considering process planning and production control issues exacerbated by the time bottlenecks introduced in downstream post-processing stages. Discrete Event Simulation (DES) was used to model production flow for two conceptual scenarios: a small-batch low-mix production environment and a high-mix variable-batch production environment. We simulated production, analyzed bottlenecks and tested intervention strategies that may be implemented: (1) increasing the availability of post-processing equipment, (2) modifying the number of available printers and (3) implementing improved workforce scheduling to reassign skilled operators during downtime of certain machines to reduce waiting time. VAM can speed up the creation of the primary part, but post-processing steps such as curing, washing and finishing the produced part might nullify those savings. Through the intervention methods we studied, the overall system utilization rate can be increased. VAM can achieve higher throughput rates in intelligent manufacturing settings only when it is incorporated into intelligent planning systems with high-speed post-processing. We provide some operational considerations in scaling up the VAM manufacturing capability, specifically focusing on planning challenges and gaps in adoption within manufacturing contexts. In this context, we find that coupling data-driven simulation methods with process planning algorithms may further improve workflow in smart manufacturing environments. Full article

Three-dimensional (3D)-printed dentures are often fabricated from a single tooth-colored resin and externally characterized using stains and glaze coatings to enhance gingival esthetics and surface properties. However, routine toothbrushing may degrade these coatings, potentially affecting surface gloss and roughness. This study evaluated the effects of stain timing and glaze application on the gloss and surface roughness of a 3D-printed denture resin following simulated toothbrushing. Eighty disc-shaped specimens (12 mm × 3 mm) were fabricated and assigned to two staining systems (OPTIGLAZE Color and Palette 2.0), with subgroups based on stain timing (before or after post-curing) and glaze application (with or without glaze) (n = 10). Specimens underwent 20,000 cycles of simulated toothbrushing, and gloss and surface roughness were measured before and after brushing. Data were analyzed using two-way ANOVA (α = 0.05). Glaze application significantly improved gloss retention for both staining systems (p < 0.001), while stain timing had no independent effect. Glaze application with Palette 2.0 demonstrated improved gloss retention when post-cured in a post-curing unit. Toothbrushing increased surface roughness in all groups, with no significant effects of stain timing or glaze. Within the limitations of this study, glaze improves gloss stability, whereas stain timing has minimal influence and does not affect surface roughness. Full article

Background/Objectives: Locoregional anal squamous cell carcinoma (ASCC) is usually cured with chemoradiotherapy; however, some patients relapse, require salvage abdominoperineal resection or develop metastatic disease. Approximately 90% of cases are driven by high-risk human papillomavirus, most commonly HPV16. Conventional surveillance using clinical examination and imaging may have limited sensitivity and specificity and is not individualized by recurrence risk. Circulating biomarkers (CBs), particularly circulating tumor DNA (ctDNA), have emerged as promising methods for real-time disease monitoring. We systematically reviewed available evidence evaluating CBs across treatment timepoints in localized ASCC. Methods: A PROSPERO-registered review (ID: 1133987) was conducted according to PRISMA guidelines. PubMed, EMBASE, Cochrane CENTRAL, Web of Science, and major conference proceedings (ASCO, ESMO, ASTRO) were searched on 30 November 2025. We included prospective or retrospective studies (≥10 patients) with stage I–III disease treated with curative-intent chemoradiotherapy that reported CBs, assay characteristics, and at least one clinical outcome. Studies with predominantly localized cohorts were included even if small proportions of metastatic patients were present, provided results relevant to curative-intent populations could be interpreted. Data were synthesized narratively by timepoint (baseline, mid-treatment, end of treatment, post-treatment/surveillance) and assay type given methodological heterogeneity. Results: Fifteen studies were included. CB assays comprised four categories: viral HPV ctDNA assays, tumor-informed ctDNA assays, non-specific total cell-free DNA (cfDNA) quantification, and circulating tumor cell (CTC)-based assays. Baseline detection rates varied by assay type. Viral HPV ctDNA assays demonstrated detection rates of 59–100%, while tumor-informed ctDNA assays showed rates of 79–89%. Across studies, higher CB detection rates and levels were generally associated with greater tumor burden, including more advanced T and N stage disease. Mid-treatment ctDNA clearance identified patients with excellent locoregional control and progression-free survival, whereas persistent ctDNA was associated with treatment failure. End-of-treatment and surveillance ctDNA positivity predicted recurrence within individual cohorts, with reported sensitivities of 80–90%, specificities of 95–99%, and molecular lead times preceding clinical or radiographic detection. In contrast, non-tumor-specific cfDNA dynamics showed more variable prognostic associations and were less consistently linked to tumor burden. Conclusions: Across heterogeneous assays, CB dynamics provide clinically meaningful prognostic information in localized ASCC, particularly when measured during treatment and early surveillance. Viral HPV and tumor-informed ctDNA may have the potential to guide follow-up intensity and inform future escalation or de-escalation strategies; however, prospective, standardized trials are needed to define actionable thresholds and test ctDNA-guided management. Full article

The increasing prevalence of cardiovascular diseases highlights the need to develop vascular grafts that match the mechanics of native vascular tissue and offer functional adaptability. This study reports the development and systematic optimization of a shape-memory polyurethane acrylate (PUA)-based photocurable resin for digital light processing (DLP)-based four-dimensional printing (4DP) applications. Resin formulations were designed by controlling hard/soft segment ratios, reactive diluent content, and crosslink density to position the glass transition temperature (T_g) within the physiological range (25–40 °C). Thermomechanical characterization was performed via dynamic mechanical analysis (DMA) and tensile testing, while a full-factorial Design of Experiments (DoE) approach was applied to optimize DLP process parameters—namely layer thickness, exposure time, and post-curing time. The developed resin formulation yielded a T_g of 38 °C as determined by DMA. Following process optimization, regression models showed high statistical fit (R² > 99%), and experimental validation under optimal conditions (layer thickness: 82.83 µm, exposure time: 11 s, post-curing: 2 min) resulted in an elongation at break of 64.0 ± 3.4%, a Young’s modulus of 10.9 ± 0.1 MPa, and a tensile strength of 6.2 ± 0.3 MPa. The optimized system exhibited thermally triggerable shape memory behavior at near-body temperature, with mechanical properties consistent with natural arterial tissue benchmarks. These findings demonstrate a promising material design strategy for DLP-based 4D-printed vascular structures. Full article

Polyurea elastomers are widely used in industry thanks to their exceptional mechanical properties. However, cold-pour systems typically require extended ambient curing times to achieve optimal performance. This study investigates whether accelerated thermal curing can replicate or exceed the mechanical properties obtained through the standard ambient cure protocol. Specimens were prepared by hand-mixing and then cured at temperatures of 50 $°\mathrm{C}$ and 70 $°\mathrm{C}$ for 1 h, 3 h and 6 $\mathrm{h}$. Selected specimens were then aged at room temperature for up to 7 d. Uniaxial tensile tests were conducted, with strain measured via a video-tracking technique. Porosity analysis was performed using cross-section micrographs. The results show that a 6 $\mathrm{h}$ cure at 50 $°\mathrm{C}$ yields mechanical properties comparable to those obtained through the standard ambient cure, while a 6 $\mathrm{h}$ cure at 70 $°\mathrm{C}$ significantly surpasses them. Post-cure aging was found to be particularly effective for specimens with a thickness of 1.5 $\mathrm{m}$$\mathrm{m}$, achieving a tensile strength of 4.7 $\mathrm{M}$$\mathrm{Pa}$ after 7 d, exceeding that declared by the manufacturer. Full article

In liquid composite moulding processes, the curing behaviour of thermoset matrices plays a decisive role in determining manufacturing quality and cycle time. Premature demoulding may lead to insufficiently cured components, whereas excessively long curing times reduce production efficiency. Reliable monitoring and modelling of the curing process are therefore essential for process optimisation. In this study, the cure kinetics of a fast-curing epoxy resin system are modelled using the Grindling kinetic model, which accounts for diffusion-controlled reaction behaviour and vitrification effects. Model parameters are identified using both dynamic and isothermal differential scanning calorimetry (DSC) measurements. In addition, the glass transition temperature is described as a function of the degree of cure using the DiBenedetto relationship. To demonstrate the applicability of the model for process monitoring, an experimental mould equipped with temperature sensors was developed to simulate real-time estimation of the degree of cure during isothermal processing. The predicted degree of cure is validated by post-process DSC analysis of the manufactured samples. Initial comparisons reveal systematic deviations caused by temperature measurement uncertainties. After implementing a temperature correction based on experimentally determined sensor deviations, the predicted degree of cure shows significantly improved agreement with DSC measurements. The results demonstrate that combining kinetic modelling with temperature monitoring enables reliable real-time estimation of the curing state for fast-curing epoxy systems. The study also highlights the critical importance of accurate temperature measurement for curing monitoring and provides insights into the practical implementation of sensor-based monitoring strategies in liquid composite moulding processes. Full article

Unsaturated polyester resin (UPR)–quartz composites have become increasingly important in structural, sanitary, and architectural applications. However, their manufacturing processes still rely heavily on empirical knowledge. This review compiles recent developments in materials science, curing kinetics, and digital manufacturing, outlining a pathway toward data-driven, adaptive production of quartz-filled thermosets. The chemical and physical fundamentals of UPR polymerization are summarized, including the influence of initiator systems, filler characteristics, and thermal management on network formation. Challenges associated with highly filled formulations—such as viscosity control, dispersion, shrinkage, and exothermic peak prediction—are discussed in detail. Recent advances in digital twins (DTs) and artificial intelligence (AI) are reviewed, demonstrating how physics-based simulations, machine learning models, and hybrid mechanistic–data-driven approaches improve the prediction of rheology, curing behavior, and quality outcomes in thermoset polymer processes. A practical application example demonstrates the prediction of peak time in quartz–UPR composites using Random Forest and Gradient Boosting ensemble models. Two prediction scenarios are evaluated: Scenario A with gel time by Leave-One-Out cross-validation, and Scenario B without gel time, representing post-mixing and pre-process prediction contexts, respectively. Stratified bootstrap augmentation improves Gradient Boosting in both scenarios. Principal component analysis confirms that the curing process is governed by three independent physical dimensions: curing reactivity, thermal environment and resin thermal state. Full article

This study addresses the challenges posed by weakly cemented strata in mine tunnels, where surrounding rock softens and deforms upon water exposure, which promotes the development of seepage pathways, and exhibits insufficient stability in bolt (cable) support systems. This study conducts laboratory grouting tests using silica sol on typical weakly cemented sandstone from Xinjiang mining areas. The mineral composition and pore structure were characterized using XRD, SEM, and mercury porosimetry. The injectable mixing ratio parameters for silica sol and the catalyst were determined through viscosity-time evolution tests. Grouting was performed using a custom-built constant-pressure grouting apparatus. After curing, unconfined compressive strength (UCS) and porosity-permeability tests were conducted to evaluate the micro-mechanism of grouting effects on the mechanical and permeability properties of weakly cemented sandstone. The results indicate: (1) The sandstone exhibits a high clay mineral content of 39.8%, dominated by illite. Its pores are primarily small-scale (10–100 nm), accounting for 79.31% of the total pore volume. This scale matches that of silica sol nanoparticles (approximately 9–20 nm), facilitating slurry penetration into micro-pores; (2) microscopic analyses reveal that silica sol effectively reconstructs pore structures through permeation filling and surface coating. Compared to KCl-induced gelation (with approximately 8% gel coverage), NaCl-induced gelation forms a more continuous gel film with more complete pore filling, achieving coverage of around 22%. Furthermore, the larger surface area of the gel aggregates indicates a more thorough filling of micro- and nano-pores, effectively enhancing rock mass compactness. (3) Permeability decreased from 6.91 mD to 3.55 mD, a reduction of 48.6%, while porosity decreased from 16.94% to 13.55%, showing a phased reduction during the grouting process; (4) following pressure grouting stabilization, the uniaxial compressive strength of sandstone increased appropriately by approximately 7–14%, while the elastic modulus rose by about 18–28%. The failure mechanism shifted from shear brittleness to a shear-tension composite state, with enhanced post-peak bearing capacity. These findings provide support for optimizing silica sol grouting parameters in weakly cemented strata tunnels and for the synergistic reinforcement of rock mass permeability and strength. Full article

Cemented paste backfill (CPB) is widely adopted in underground mines, where the shear resistance of the CPB–rock interface critically governs the integrity of backfill–rock systems. This study investigates the effects of polypropylene fiber reinforcement, surface roughness (Joint Roughness Coefficient, JRC = 0 and 1.76), and curing time (1, 3, and 7 days) on the shear strength and deformation characteristics of CPB–rock interfaces. Direct shear tests were performed under normal stresses of 50, 100, and 150 kPa, with synchronous measurements of shear and vertical displacements. Results show that increasing roughness markedly strengthens the interface, with the peak shear stress rising by up to 45% due to enhanced mechanical interlocking and dilation. In contrast, adding 0.5 vol.% PP fibers slightly reduces peak shear capacity but consistently improves post-peak deformability, indicating a transition from brittle interfacial fracture to a more ductile, progressive failure mode. A three-stage mechanical model was established to describe the shear stress–displacement relationship, incorporating elastic, bond degradation, and frictional sliding phases. The model parameters, including the shear stiffness ($K_s$), bond degradation coefficient ($\eta$), and residual strength (${\tau }_r$), were calibrated using the experimental data. Mohr–Coulomb analysis further quantifies the curing-dependent evolution of interfacial strength parameters, highlighting a marked increase in cohesion from 1 to 7 days alongside roughness-governed peak strengthening. This research provides insights into the optimization of the CPB–rock interface design for enhanced geomechanical performance in underground applications. Full article

Background: Hepatocellular carcinoma (HCC) is a major cause of mortality in the United States, but it can be cured with orthotopic liver transplant (OLT) in selected patients. Despite curative intent, post-OLT recurrence can occur in up to 15% of patients. The need for a program of post-OLT surveillance is widely accepted but the specifics of an optimal program have not been established. There is interest in identifying lower-risk cohorts of patients in whom an abbreviated strategy of surveillance may prove adequate, utilizing tools such as the RETREAT score. Unique challenges are posed in the post-transplant population regarding safety and tolerability of systemic therapy for HCC recurrence, suggesting early detection is beneficial. Methods: This was a single-center retrospective analysis of characteristics and outcomes for all patients undergoing transplant at our center between 1 January 2012 and 31 December 2024. Diagnosis of HCC was determined by histological confirmation or Liver Imaging and Reporting Data System (LI-RADS) 5 findings on contrast-enhanced cross-sectional imaging. RETREAT scores were calculated for all patients. Results: During the study period, 923 transplants were performed, of which 329 (35.6%) were for HCC. Post-OLT recurrence occurred in 36 (10.9%) of these. Recurrence was associated with the presence of any viable tumor on explant surgical pathology, the presence of a viable tumor beyond Milan Criteria, the presence of microvascular invasion, a larger diameter of viable tumor on explant, and a higher RETREAT score. Although higher RETREAT scores were associated with post-OLT recurrence, one-third of patients who experienced post-OLT recurrence had RETREAT scores of 0 or 1. RETREAT scores did not correlate with the time interval between transplant and HCC recurrence. Systemic therapy proved challenging, with 10/25 patients receiving systemic therapy for post-OLT recurrence having to stop or alter regimens due to the severity of adverse effects. Conclusions: The rates of post-transplant recurrence and the experience of patients managed with systemic therapy for post-OLT recurrence in our experience were in line with previously published data. Due to the overall low RETREAT scores, the sensitivity of the RETREAT score in identifying patients at risk for post-OLT recurrence was limited, and the low RETREAT score had very limited incremental negative predictive value for identifying a low-risk population. This suggested that a broad screening strategy for post-OLT recurrence may be better than a personalized strategy in which patients with low RETREAT scores receive abbreviated surveillance. Full article

While the effects of formulation variables of a rubber compound are well established for conventional rubber manufacturing techniques, their role in extrusion-based additive manufacturing remains underexplored. This study explores the impact of different base rubbers (NBR and EPDM) and curing agents (sulfur and peroxide) on processability and final part characteristics in material extrusion additive manufacturing applications. Under identical printing conditions, sulfur-cured NBR exhibits greater post-print shrinkage (12%) than sulfur-cured EPDM (7%). However, sulfur-cured NBR achieves a higher degree of adhesion between printed layers than sulfur-cured EPDM, as suggested by the % retention of the bulk materials’ ultimate stress by the printed parts (84–100% and 51–62%, respectively). Additionally, a peroxide-cured NBR formulation was compared against the same sulfur-cured NBR formulation. Printed parts from the peroxide-cured NBR formulation showed higher shrinkage (16%) and lower % retention of the bulk materials’ ultimate stress (26–33%) than the sulfur-cured NBR formulation. Additionally, the tensile behavior of all three rubber compounds was found to be strongly dependent on printing orientation, showing the anisotropic behavior typical of extrusion-based additive manufacturing. Sulfur-cured NBR showed the least anisotropy for stress at break (0.82) and strain at break (0.90), whereas peroxide-cured NBR showed the highest anisotropy in stress (0.74) and strain (0.82). The anisotropy ratios for sulfur-cured NBR and EPDM compounds were very similar for stress (0.82 vs. 0.82) and comparable for strain (0.90 vs. 0.87). Notably, the peroxide cure system provided almost twice as much available printing time as the sulfur cure system. This report on the effects of base rubber and curing agents on 3D printability and part properties provides a background to guide future efforts to design rubber compounds for 3D printing applications. Full article

Background: Direct-acting antiviral (DAA) therapy has transformed chronic hepatitis C virus (HCV) infection into a curable disease. Beyond viral eradication, increasing attention has been directed toward metabolic changes following sustained virological response (SVR), particularly alterations in lipid metabolism. This study aimed to assess the long-term evolution of lipid parameters after HCV cure in a real-world clinical cohort. Methods: We conducted a prospective, single-center observational study including 85 patients with chronic HCV infection who achieved SVR after DAA therapy. Lipid parameters, including total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides, were assessed at baseline and during post-SVR follow-up at 24, 48, and 96 weeks. Body mass index (BMI) and non-invasive fibrosis indices were also evaluated. Longitudinal changes were analyzed using mixed-effects models. Results: Total cholesterol increased from 157.7 ± 35.6 mg/dL at baseline to 179.6 ± 42.9 mg/dL at SVR 24 and further to 189.0 ± 40.3 mg/dL at SVR 48, stabilizing at 177.7 ± 38.3 mg/dL at SVR 96. LDL-C showed a similar trajectory from 94.6 ± 30.8 mg/dL at baseline to 107.5 ± 33.3 mg/dL at SVR 24, further raising to 115.7 ± 36.2 mg/dL at SVR48, and 111.8 ± 39.5 mg/dL at SVR 96. HDL-C showed minimal change, while triglycerides demonstrated greater interindividual variability without a consistent population-level trend. BMI remained stable over follow-up (26.6 ± 4.7 to 27.6 kg/m²). Linear mixed-effects models confirmed a significant effect of time after SVR on total cholesterol and LDL-C (p < 0.05). Conclusions: In this real-world cohort, HCV cure with DAA therapy was associated with sustained long-term changes in lipid metabolism, characterized by increases in total cholesterol and LDL-C independent of major weight changes. These findings support the importance of continued metabolic monitoring after SVR, particularly in patients with additional cardiometabolic risk factors. Full article