University of Phayao

Tunnel stability in tectonically disturbed rock masses remains particularly challenging near rock–soil interfaces, where abrupt stiffness contrasts and heterogeneous geological structures can trigger collapse mechanisms that conventional rock mass classification systems do not adequately capture. This study identifies and quantifies a geometry-controlled instability mechanism governing tunnels excavated near rock–soil interfaces under low-to-medium overburden conditions.The analysis combines 26 roof-collapse incidents recorded in three railway tunnels and one adit in Northern Thailand with geological mapping, RMR–GSI characterization, construction records, convergence monitoring, and two-dimensional finite element analyses. Results from the Phayao Tunnel demonstrate that the occurrence of collapse is governed not only by rock mass quality but also by the effective thickness of competent material available above the excavation. A normalized interface-depth parameter V/H is introduced to quantify this confinement condition.Field observations and numerical simulations show that when V/H decreases below approximately 2.5, the compressive arch above the tunnel crown becomes progressively truncated, leading to reduced confinement, increased deformation, and increased collapse susceptibility. A collapse-risk framework integrating rock mass quality, effective confinement, and interface geometry is proposed. Although additional validation is required in other geological environments, the proposed approach provides a mechanics-based framework for identifying interface-controlled instability and supporting adaptive excavation and reinforcement strategies.

Livestock productivity in tropical regions is constrained by low-quality roughages that limit intake, digestibility, and animal performance. Liquid feed supplementation, particularly molasses-based formulations combined with urea, has emerged as an effective strategy to overcome these limitations. Molasses provides readily fermentable carbohydrates that stimulate rumen microbial activity, enhance the fermentation of fibrous feeds, and increase dry-matter intake. Urea contributes a nitrogen source for microbial protein synthesis, thereby improving crude-protein digestibility and nutrient utilization. Numerous studies have reported that liquid feed supplementation can enhance rumen fermentation efficiency, increase volatile fatty acid (VFA) production, and may support the activity of cellulolytic bacteria responsible for fiber degradation. Although the rapid hydrolysis of urea may lead to elevated ruminal ammonia concentrations, this risk can be effectively managed through appropriate formulation and feeding practices. Liquid feed supplementation has also been shown to improve growth performance and, in some cases, milk yield and composition. Further research is needed to optimize the balance between nitrogen and energy release, establish species-specific supplementation rates, and evaluate long-term effects on animal health and sustainability. Overall, liquid feed supplementation represents a practical feeding strategy with potential economic advantages for improving feed utilization and productivity in tropical ruminant systems.

Post-recycling plastic waste contamination in freshwater ecosystems represents an escalating environmental threat, while algal blooms continue to generate vast quantities of underutilized biomass. Addressing both challenges, this study investigated the co-hydrothermal liquefaction of Chlorella pyrenoidosa with representative post-recycling plastic wastes polypropylene, polyethylene terephthalate, and Nylon-6 as a dual-resource valorization strategy. Experiments were conducted in a 1000 mL high-pressure batch reactor at 350 degrees C for 30 min, with varying biomass-to-plastic feed ratios. Systematic product characterization, including functional group, elemental analysis, Van Krevelen diagrams, and heating value assessment, was employed to elucidate synergistic effects and evaluate product quality. Results revealed that co-processing with polyethylene terephthalate achieved the highest biocrude yield of 71.5%, with an enhanced higher heating value of 35.7 MJ kg-1, surpassing the 62.4% yield from microalgae alone. Nylon-6 blends also improved oil yield to 69.6% while producing aqueous fractions enriched with epsilon-caprolactam, indicating the recovery of valuable nitrogenous monomers. In contrast, PP exhibited limited reactivity toward oil generation but produced carbon-rich biochar with a higher heating value up to 41.4 MJ kg-1, comparable to high-grade solid fuels. Mechanistic analyses confirmed that plastics acted as hydrogen donors, promoting deoxygenation, radical stabilization, and selective depolymerization, thereby improving both liquid and solid fuel fractions. By employing ecologically relevant freshwater feedstocks from Thailand, this work advances beyond prior studies dominated by marine biomass or synthetic surrogates, providing realistic insights into resource integration within polluted inland waters. The co-hydrothermal liquefaction process simultaneously mitigates eutrophication-driven algal blooms and persistent plastic pollution while generating fuels and functional carbon materials, directly contributing to a circular bioeconomy. The demonstrated synergy between biological and synthetic wastes highlights a scalable, catalyst-free route to energy-dense biofuels and multifunctional biochar. These outcomes align strongly with SDG which offer a pragmatic framework for waste-to-energy transition in freshwater-dependent regions.

Solid drug-hydroxypropyl-β-cyclodextrin (HPβCD) inclusion complexes are used to enhance drug solubility and microneedle (MN)-mediated delivery efficiency. However, mechanistic understanding of HPβCD effects in solution on drug transport across pathways in MN-pretreated skin remains limited. This study investigated the in vitro permeation of rhein (RN) across MN-pretreated neonatal porcine skin from saturated RN solutions containing 0–200 mM HPβCD. Phase solubility, total flux (Jtotal), and permeability coefficient through the microchannel pathway (PMCP) were determined, along with dermal transport at varying HPβCD concentrations. Permeation experiments under asymmetric and symmetric donor–receiver HPβCD conditions were conducted to elucidate potential interactions between HPβCD and skin transport pathways. RN solubility increased from 241.9 ± 16.4 µg/mL (0 mM HPβCD) to 1,092.5 ± 54.9 µg/mL (200 mM HPβCD), showing a linear trend up to 50 mM. MN permeation studies confirmed that RN transport occurred predominantly through microchannels. The highest Jtotal (3.87 ± 0.40 μg/cm2/h) was achieved at 25 mM HPβCD, with no further enhancement at higher concentration. Although increasing HPβCD concentration improved RN solubility, PMCP and dermal transport decreased. Identical permeation profiles under symmetric and asymmetric conditions at 50 mM HPβCD indicated no direct interaction between HPβCD and MN-pretreated skin. In summary, HPβCD-mediated solubility enhancement increased RN flux across MN-pretreated skin, but not microchannel permeability or dermal diffusion.

Background: The 1 min sit-to-stand test (1-MSTST) is a widely used functional assessment involving repetitive sit-to-stand transitions. This study examined local dynamic stability during the 1-MSTST across three acceleration directions, compared young and middle-aged women, and explored associations between body composition and stability. Methods: Twenty-four young adult women (24.1 +/- 5.2 years) and twenty-four middle-aged women (51.4 +/- 5.9 years) performed the 1-MSTST. Trunk accelerations were recorded using a tri-axial accelerometer at L5. Local dynamic stability was quantified using the largest Lyapunov exponent (LyE), and movement magnitude using root mean square (RMS). Directional, group, and correlational analyses were performed with correction for multiple testing. Results: Significant directional differences were observed for both LyE and RMS, with all pairwise contrasts between mediolateral (ML), anteroposterior (AP), and vertical (VT) directions remaining significant after correction (p < 0.001). Apparent age effects in LyE were no longer significant after adjusting for cadence, BMI, and multiple testing, indicating no robust age-related difference in local dynamic stability. Body fat percentage showed moderate positive correlations with LyE in the VT (p = 0.003) and AP (p = 0.003) directions. Muscle mass percentage showed a moderate positive correlation with VT LyE (p = 0.002) and moderate negative correlations with ML (p = 0.002) and AP LyE (p = 0.002). Conclusions: Stability during the 1-MSTST differs by direction, with the greatest variability in the mediolateral axis. No independent age effect was found. Higher body fat relates to poorer stability, while greater muscle mass supports better movement control.