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The canal is crucial for water diversion projects, but it is susceptible to frost damage. To address this, a two-layer composite geomembrane lining structure (TLCGLS) was proposed that regulates the interaction between canal lining and frozen soil. Model tests were conducted to investigate its anti-frost heave effectiveness. Considering the interaction among the lining, two-layer composite geomembranes (TLCGs), and frozen soil, a canal frost heave model with heat-water-mechanical coupling was developed. The influence of canal cross- shapes and TLCGs arrangements on anti-frost heave performance and mechanism of TLCGLS were discussed. Results show that TLCGLS reduces uneven frost heave degree and compressive/tensile strains of the lining by 35%, 29%, and 28% respectively. During melting, it rapidly reduces frost heave, tangential deformation, and strain with minimal residual effects. TLCGLS demonstrates strong resetting ability and excellent anti-frost heave performance. It is particular suitable for arc-bottomed trapezoidal canals. However, excessive reduction in friction between TLCGs weakens arching effect of the bottom lining, increasing tensile stress and safety risks. TLCGLS with geomembrane-geotextile contact exhibits superior anti-frost heave performance, mitigating compressive stress by over 50% while meeting design requirements for tensile stress. These findings provide a theoretical basis and technical solution for mitigating frost damage in canals.

期刊论文 2025-04-01 DOI: 10.1016/j.geotexmem.2024.11.013 ISSN: 0266-1144

Soil liquefaction caused by earthquakes is a devastating occurrence that can compromise the foundations of buildings and other structures, leading to considerable economic losses. Among the new remedies against liquefaction, Induced Partial Saturation (IPS) is regarded as one of the most promising technologies. In order to improve liquefaction resistance and the fluid phase's compressibility, gas or air bubbles are introduced into the pore water of sandy soils. This article deals with the general laboratory evaluation of a sand under partially saturated conditions and under cyclic loading to assess if this technology is applicable for a ground improvement of the examined soil. The use of the Axis Translation Technique for sample desaturation and diffusion-stable butyl membranes significantly influences the laboratory results. Additionally, it is found that the trapped air bubbles of the partially saturated samples act like a damping mechanism, which are reflected in the stress paths of the deviator stress q over the mean pressure p with an inclination of 1 : 3. Zum Verfl & uuml;ssigungsverhalten von teilges & auml;ttigtem SandDie durch Erdbeben verursachte Bodenverfl & uuml;ssigung ist ein verheerendes Ereignis, das die Fundamente von Geb & auml;uden und anderen Bauwerken gef & auml;hrden und zu erheblichen wirtschaftlichen Verlusten f & uuml;hren kann. Die induzierte partielle S & auml;ttigung (Induced Partial Saturation, IPS) gilt als eine der vielversprechendsten Technologien unter den neuartigen Baugrundverbesserungen gegen Verfl & uuml;ssigung. Um den Verfl & uuml;ssigungswiderstand und die Kompressibilit & auml;t der fl & uuml;ssigen Phase zu verbessern, werden dabei Gas- oder Luftblasen in das Porenwasser sandiger B & ouml;den eingebracht. Dieser Beitrag besch & auml;ftigt sich mit der generellen labortechnischen Evaluierung eines Sandes unter teilges & auml;ttigten Verh & auml;ltnissen und unter zyklischer Beanspruchung zur Beurteilung, inwiefern sich diese Baugrundverbesserung f & uuml;r den untersuchten Boden eignet. Die Verwendung der Axis Translation Technique zur Probenentw & auml;sserung und die Verwendung von diffusionsstabilen Butylmembranen haben einen erheblichen Einfluss auf die Laborergebnisse. Au ss erdem ist festzustellen, dass die eingeschlossenen Luftblasen der teilges & auml;ttigten Proben wie eine D & auml;mpfung wirken und sich in den Spannungspfaden der Deviatorspannung q & uuml;ber dem mittleren Druck p mit einer Neigung 1 : 3 widerspiegeln.

期刊论文 2025-03-01 DOI: 10.1002/gete.202400032 ISSN: 0172-6145

Per- and polyfluoroalkyl substances (PFAS) are commonly used in proton exchange membrane fuel cells due to their high stability and resistance. These ionomers act as binding agents and their hydrophobic effect helps to remove excess water from the gas diffusion layer. Their proton conductivity and hydrophobicity, gained by incorporation of functional side chains, are essential features for their application as membranes.. However, the harsh conditions in fuel cells can lead to degradation of PFAS compounds, which are released into the environment. Due to their persistence, there are growing concerns about the enrichment of PFAS in groundwater and soil. As these substances accumulate in the environment, they are incorporated by living organisms through drinking water and plants. Some of these substances are associated with causing health disorders, such as cancer, brain and liver damage, and negative impacts on embryo development. This review highlights the sources of PFAS during fuel cell production, operation and recycling and currently available alternatives used in proton exchange membrane fuel cells. The degradation of fuel cells during operation has the potential to result in the emission of PFAS. Membrane degradation mechanisms have been investigated and results can serve as a foundation to reduce PFAS emissions by identifying critical operating conditions.

期刊论文 2025-02-28 DOI: 10.1016/j.jpowsour.2024.236104 ISSN: 0378-7753
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