Defect-rich MoS sub(2) ultrathin nanosheets are synthesized on a gram scale for electrocatalytic hydrogen evolution. The novel defect-rich structure introduces additional active edge sites into the ...MoS sub(2) ultrathin nanosheets, which significantly improves their electrocatalytic performance. Low onset overpotential and small Tafel slope, along with large cathodic current density and excellent durability, are all achieved for the novel hydrogen-evolution-reaction electrocatalyst.
The repairs of building structures are inevitable and indispensable. Repairs are used to restore or maintain the usability of existing facilities, often contributing to the extension of their ...expected service life, increasing the sustainability of building resources. Given that conservation rules are observed, repairs are also used to save monuments. The concept of repair durability brings to the foreground the durability of the repaired structure (after repair): what service life has been obtained/recovered as a result of the repair. Based on the available data (limited set), a generalised distribution function of repair durability was developed, with a disappointing course. This, however, applies (necessarily) to the past. Significant progress was shown to have been achieved in the theoretical and technical fundamentals of technical repair measures. In this situation, a prognostic distribution function was also designed for future repairs according to EN 1504. A rule of thumb called estimating concrete repair durability, CRD was proposed. The risk associated with estimating the durability of repairs was indicated. A reason for optimism is that proactive monitoring of the condition of the structure and, consequently, management of the repair strategy allows to reach the designed life of the structure.
The alkaline stability of N‐heterocyclic ammonium (NHA) groups is a critical topic in anion‐exchange membranes (AEMs) and AEM fuel cells (AEMFCs). Here, we report a systematic study on the alkaline ...stability of 24 representative NHA groups at different hydration numbers (λ) at 80 °C. The results elucidate that γ‐substituted NHAs containing electron‐donating groups display superior alkaline stability, while electron‐withdrawing substituents are detrimental to durable NHAs. Density‐functional‐theory calculations and experimental results suggest that nucleophilic substitution is the dominant degradation pathway in NHAs, while Hofmann elimination is the primary degradation pathway for NHA‐based AEMs. Different degradation pathways determine the alkaline stability of NHAs or NHA‐based AEMs. AEMFC durability (from 1 A cm−2 to 3 A cm−2) suggests that NHA‐based AEMs are mainly subjected to Hofmann elimination under 1 A cm−2 current density for 1000 h, providing insights into the relationship between current density, λ value, and durability of NHA‐based AEMs.
This work systematically explores the alkaline stability and degradation mechanism of 24 representative N‐heterocyclic ammonium groups and poly(aryl piperidinium)‐based polyelectrolytes for anion‐exchange‐membrane fuel cells (AEMFCs), providing a clear guideline for design of highly stable anion‐exchange membranes and ionomers. The structure–durability relationship between ammonium groups, anion‐exchange polyelectrolytes, and AEMFCs was revealed.
Abstract
Electrochemical water splitting is a common way to produce hydrogen gas, but the sluggish kinetics of the oxygen evolution reaction (OER) significantly limits the overall energy conversion ...efficiency of water splitting. In this work, a highly active and stable, meso–macro hierarchical porous Ni
3
S
4
architecture, enriched in Ni
3+
is designed as an advanced electrocatalyst for OER. The obtained Ni
3
S
4
architectures exhibit a relatively low overpotential of 257 mV at 10 mA cm
−2
and 300 mV at 50 mA cm
−2
. Additionally, this Ni
3
S
4
catalyst has excellent long‐term stability (no degradation after 300 h at 50 mA cm
−2
). The outstanding OER performance is due to the high concentration of Ni
3+
and the meso–macro hierarchical porous structure. The presence of Ni
3+
enhances the chemisorption of OH
−
, which facilitates electron transfer to the surface during OER. The hierarchical porosity increases the number of exposed active sites, and facilitates mass transport. A water‐splitting electrolyzer using the prepared Ni
3
S
4
as the anode catalyst and Pt/C as the cathode catalyst achieves a low cell voltage of 1.51 V at 10 mA cm
−2
. Therefore, this work provides a new strategy for the rational design of highly active OER electrocatalysts with high valence Ni
3+
and hierarchical porous architectures.
Background Valve in Valve Transcatheter Aortic Valve Replacement (VIV TAVR) in failed surgical bioprostheses may be limited by patient prosthesis mismatch (PPM), which has been associated with ...decreased survival at 1 year. Bioprosthetic valve fracture (BVF) to facilitate VIV TAVR is a safe and effective method to improve procedural hemodynamics, yet the durability of hemodynamic result is not known.
A diffusion–reaction numerical model is proposed to simulate the response of concrete exposed to external sulfate attack. Diffusion properties are modified based on the strain reached and the ratio ...of porosity filled by ettringite. A direct and intuitive approach is proposed for the consideration of the diffusion in a cracked porous media based on the constitutive law of the material. A methodology to compute expansions based on a more realistic consideration of the concrete porosimetry is presented, by which it is possible to distinguish different strain contributions from different pore sizes. The described approach also allows the consideration of different capacities to accommodate expansive product for each pore size considered and the faster filling rate existent in small pores. Critical parameters of the numerical model developed are recognized and established. Expansions obtained by the new model are in good agreement with experimental data published in the literature.
Leaching and external sulphate attack on concrete lead to dissolution of hydration products, mainly portlandite, and in case of ingress of sulphate ions to formation of expansive products such as ...gypsum and ettringite. Durability of concrete exposed to these environments is still based on prescriptive specifications. The aim of the study is to provide experimental data to design performance based tests and specifications for a comparative approach. Tests have been developed to study these degradations in controlled conditions at constant pH. A leaching test has been performed on concrete. Indicators can be deduced from the leaching test and they are sensitive to the variations of potential durability. An accelerated test using a high sulphate concentration has been performed on mortars. Expansion results are sensitive to mortar mix proportions and the test could be used to qualify cements or binders in a comparative approach. Concrete specimens are exposed to external sulphate attack at two levels of sulphate concentration to provide long-term data that can be used to study the relevance of the accelerated tests and models which are being developed. Results from both series of tests show a correlation between the resistance to leaching and the resistance to external sulphate attack.
•Comparative analysis of compactness, fatigue durability, ageing resistance of different asphalt mixtures.•Durability evaluation of different asphalt mixtures.•Field effect evaluation of easy ...compaction and high-durability ultra-thin overlay.•The durability evaluation system of ultra-thin overlay.
As one of the most popular preventive maintenance of road surface, the ultra-thin overlay with good durability and surface function could provide better conditions for the safe and smooth running of vehicles. The objective of this study is to prepare an ultra-thin overlay with easy compaction and high-durability (ECHD) and to evaluate its durability. First, the optimal dosage of the easy compaction modifier was determined based on the grey theory. Then, matrix asphalt and SBS-modified asphalt mixtures were used as control groups. Through an experimental design, the ease of compaction, fatigue durability, ageing resistance, surface function durability, and interlayer durability of the three asphalt mixtures were compared. Finally, using the test road, a field effect evaluation of the durability of the ECHD ultra-thin overlay was performed, and a durability evaluation system for ultra-thin overlays was established. The results showed that the optimal content of the modifier was 6%. The ECHD asphalt mixture exhibited the smallest Compaction energy index (CEI), largest compaction rate (K), and easiest compaction. The splitting strength ratio was used as the ageing coefficient to evaluate the ageing performance. Compared with the matrix asphalt and SBS-modified asphalt mixture, the ECHD asphalt mixture exhibited better ageing durability and fatigue durability. Moreover, after 30,000 wear times, the mass loss rate of ECHD ultra-thin overlay was 0.4%, the texture depth and pendulum value decreased by 25% and 16%, and the shear strength and pull-off strength decreased by 6% and 20% respectively, which showed that it had the best performance in wear-resistance, skid-resistance, water-impermeable and interlayer durability. In addition, the durability effect of the ECHD ultra-thin overlay test road was evaluated and a durability evaluation system of the ECHD ultra-thin overlay was proposed, which can act as a reference for the durability evaluation of the same type of overlays.
The authors propose that purchasing luxury can be a unique means to engage in sustainable consumption because high-end products are particularly durable. Six studies examine the sustainability of ...high-end products, investigate consumers’ decision making when considering high-end versus ordinary goods, and identify effective marketing strategies to emphasize product durability, an important and valued dimension of sustainable consumption. Real-world data on new and secondhand accessories demonstrate that high-end goods can be more sustainable than mid-range products because they have a longer life cycle. Furthermore, consumers engage in more sustainable behaviors with high-end goods, owning them for longer and disposing of them in more environmentally friendly manners. Nevertheless, many consumers prefer to concentrate their budget on multiple ordinary goods in lieu of fewer high-end products partly because of product durability neglect, a failure to consider how long a product will last. Although consumers generally believe that high-end products last longer, they fail to take such a notion into account when making purchases. Finally, this research offers actionable strategies for marketers to help consumers overcome product durability neglect and nudge them toward concentrating their budget on fewer high-end, durable products.
The decline in road service conditions in the form of road damage can be caused by water due to high rainfall so that it enters the pavement layer. This study aims to determine the durability or ...resistance of the AC-WC mixture using Mount Baba stone. By using the Marshall test method, the results obtained through the Marshall immersion test with variations in immersion time from 0.5 hours - 60 hours, namely the durability value of 95.02 % - 86 34%. Thus, there is a decrease in the durability of the mixture with the duration of the immersion time. This is due to the large number of cavities and pores filled with water, the mixture becomes impermeable or easily damaged.
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