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Dynamic changes in body fat distribution, ectopic fat, and related metabolic improvement in response to weigt loss in obesity
Stress-dependent erosion and post-failure morphology at soil–structure interface: insights from spatially zoned dyed soil
Mechanism-based differentiation of dissolution- and crystallization-dominant acid degradation in nanosilica-modified geopolymer mortars
Abstract Despite extensive studies on acid resistance in geopolymer mortars and nanosilica modification, degradation mechanisms are still largely inferred from isolated performance indicators such as strength loss or mass change, limiting mechanistic interpretation across different acid chemistries. In this study, a multi-parameter, mechanism-oriented evaluation framework is proposed to distinguish acid-type-dependent degradation regimes in nanosilica-modified metakaolin (MK) and fly ash (FA) geopolymer mortars exposed to hydrochloric (HCl, 4%) and sulfuric (H₂SO₄, 3%) acid environments. Mass change (ΔK), dimensional variation (ΔD), amorphous phase reduction quantified by XRD-based amorphous dome integration (ΔAmorphous), and strength retention (SR) were evaluated concurrently and statistically correlated across four acid–binder systems. The results demonstrate that HCl exposure induces a dissolution-dominated degradation regime, in which strength retention is primarily governed by the stability of the amorphous geopolymer phase, as evidenced by strong negative ΔK–ΔAmorphous correlations (ρ = −0.87 to − 0.90) and positive ΔAmorphous–SR relationships. In contrast, H₂SO₄ exposure leads to a crystallization-dominated regime characterized by sulfate-induced secondary phase formation and crystallization pressure, where strength loss shows a weak dependence on amorphous phase degradation and is instead controlled by internally generated microstructural stresses. Nanosilica exhibits a distinct acid-dependent dual role: low dosages (1–1.5%) enhance gel compactness and restrict ion diffusion, whereas excessive content (2%) accelerates microstructural embrittlement by amplifying crystallization-pressure-driven damage in sulfate environments. Overall, the findings reveal that acid resistance in geopolymer mortars is governed by distinct, quantifiable degradation regimes dictated by acid chemistry. Beyond geopolymer systems, the proposed framework offers a transferable, mechanism-based strategy for interpreting degradation processes in amorphous and nano-modified cementitious materials under aggressive chemical environments.
Study on plastic zone expansion of surrounding rock in rectangular roadway based on D-P criterion
Effects of blood flow restriction training on cardiovascular autonomic function in middle-aged and older adults: a meta-analysis
Depressive symptom trajectories and the risk of cardiometabolic multimorbidity in Chinese middle-aged older adults
Vitamin A supplementation uptake and its associated factors among Ethiopian children aged 6–59 months: community-based cross-sectional study
Data-driven and physics-inspired sound synthesis of ocean waves incorporating screened foam particles and projective space
Experimental and machine learning analysis of injector hole diameter effects on performance and emissions in an ammonia-biodiesel dual-fuel diesel engine
MMViT: Bridging Mamba and Attention for efficient video action recognition in sports
Risk management and operational efficiency in underground coal mining using circular Pythagorean fuzzy CRITIC WASPAS approach with prioritized weights
An epitope-based peptide vaccine targeting influenza a elicits robust immune responses and induces protection in a mouse model
Gender moderation in the association between academic stress, sleep quality, and adolescent mental health
Karst groundwater cycle model, hydrochemical characteristics and tectonic controls of the Shuimocao karst spring basin in the Northern Taihang Mountains, China
Previously undocumented subglacial lake beneath Flade Isblink stores most of catchment runoff and delays its release
Abstract We report the discovery of a previously undocumented subglacial lake beneath the Flade Isblink Ice Cap in North East Greenland. Using satellite Earth Observation data (ICESat-2 elevation data and Sentinel-1 Double Difference InSAR) in the period October 2018 to December 2024 and outputs from a regional climate model, we quantify the lake’s role in regional hydrology. The subglacial lake’s volume is characterised by an annual cycle of filling during the melt season and drainage in September-October, with the lake storing up to 63 ± 23% of the yearly runoff from its catchment area. In most years, lake drainage causes a 2–3-month lag between peak surface-meltwater production and downstream discharge into the nearby proglacial lake, Romer Sø. Lake drainage occurred in all years of our observation period except 2022, which had the lowest surface melt rates, suggesting that a minimum water-input threshold is required to initiate lake drainage. Additionally, our dataset does not show any evidence of a hydrological connection between the lake and the nearby, well-known subglacial lake on the high plateau of Flade Isblink. Our findings highlight how subglacial conditions may substantially modify the outflow of subglacial water to the ice margin with potential impacts on downstream hydrology and ecosystems. It further demonstrates the potential of integrating remote sensing with hydrological modelling to understand ice-sheet hydrology.