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Lithium-ion batteries on electric vehicles have been increasingly deployed for the enhancement of grid reliability and integration of renewable energy, while users are concerned about extra battery degradation caused by vehicle-to-grid (V2G) operations. This paper details a multi-year cycling study of commercial 24 Ah pouch batteries with Li(NiMnCo)O2 (NCM) cathode, varying the average state of charge (SOC), depth of discharge (DOD), and charging rate by 33 groups of experiment matrix. Based on the reduced freedom voltage parameter reconstruction (RF-VPR), a more efficient non-intrusive diagnosis is combined with incremental capacity (IC) analysis to evaluate the aging mechanisms including loss of lithium-ion inventory and loss of active material on the cathode and anode. By analyzing the evolution of indicator parameters and the cumulative degradation function (CDF) of the battery capacity, a non-linear degradation model with calendar and cyclic aging is established to evaluate the battery aging cost under different unmanaged charging (V0G) and V2G scenarios. The result shows that, although the extra energy throughput would cause cyclic degradation, discharging from SOC 90 to 65% by V2G will surprisingly alleviate the battery decaying by 0.95% compared to the EV charged within 90–100% SOC, due to the improvement of calendar life. By optimal charging strategies, the connection to the smart grid can potentially extend the EV battery life beyond the scenarios without V2G. [ABSTRACT FROM AUTHOR]

Biochemical and biomolecular archaeology is increasingly used to elucidate the consumption, use, origin, and trade of plants in the past. However, it can be challenging to use biomarkers to identify the taxonomic origin of archaeological plants due to limited knowledge of molecular survival and degradation for many key plant compounds in archaeological contexts. To gain a fundamental understanding of the chemical alterations associated with chemical degradation processes in ancient samples, we conducted accelerated degradation experiments with essential oil derived from cedar (Cedrus atlantica) exposed to materials commonly found in the archaeological record. Using GC-MS and multivariate analysis, we detected a total of 102 compounds across 19 treatments that were classified into three groups. The first group comprised compounds that were abundant in fresh cedar oil but would be unlikely to remain in ancient residues due to rapid degradation. The second group consisted of compounds that remained relatively stable or increased over time, which could be potential biomarkers for identifying cedar in archaeological residues. Compounds in the third group were absent in fresh cedar oil but were formed during specific experiments that could be indicative for certain storage conditions. These results show that caution is warranted for applying biomolecular profiles of fresh plants to ancient samples and that carefully designed accelerated degradation experiments can, at least in part, overcome this limitation. [ABSTRACT FROM AUTHOR]

Solenoid valves are important electromagnetic devices which are used widely in various fields. Considering the uncertainty of failure mechanisms in practical operation, a thermal-structure coupled model of a direct action solenoid valve is constructed by using the finite element method. The coupled model provides useful information such as temperature distribution and stress distribution for failure mechanism study of the solenoid valve. The model results predict that the failure of the solenoid valve is closely related to the thermal expansion inside the coil, which means the high temperature generated by thermal expansion melts the insulation layers. Under the combined action of high temperature and coupled stress, the shorting of coils occurs and the resistance decreases which may cause the eventual failure of the solenoid valve. To verify the prediction of the finite element model, a degradation experiment is designed. The results suggest that the failure of the solenoid valve is a gradual degradation process, and there are several mutations of coil temperature and resistance. The high temperature melts the insulation layers and causes the shorting of coils, which further decreases the resistance and increases the current. Later more heat is generated to rise coil temperature and melt insulation layers, which will short out the coils and drop the resistance. With such a relationship, as the temperature rises alternately, the resistance decreases alternately until the solenoid valve completely fails. The model provides a reference for failure mechanism study and life prolonging research of solenoid valves.

The development and application of biodegradable ureteral stents is of clinical significance for patients with ureteral stenosis and obstruction. We prepared five types of degradable monofilament, namely poly‐L‐lactide, poly(L‐lactide‐co‐ glycolide) (85% L‐lactide, 15% glycolide), poly(L‐lactide‐co‐glycolide‐co‐ε‐ caprolactone) (89% L‐lactide, 8% glycolide, and 3% ε‐caprolactone), poly(L‐lactide‐ co‐D,L‐lactide) (95% L‐lactide, 5% D,L‐lactide), and poly(lactide‐co‐ε‐caprolactone) (95% L‐lactide, 5% ε‐caprolactone), by melt extrusion and secondary drawing processes, after which degradation experiments were carried out in simulated urine at 37°C for 2 months. Because residues in the urinary systems of patients can cause complications, it is important that biodegradable ureteral stents are completely degraded after 6 weeks. Poly‐L‐lactide did not completely degrade under the abovementioned conditions and its molecular weight changed little. On the other hand, the poly(L‐lactide‐co‐glycolide) monofilament degraded slightly faster than that prepared from poly‐L‐lactide; however it maintained a certain mechanical strength after 8 weeks, which is not ideal for a woven ureteral stent. The poly(L‐lactide‐co‐D,L‐lactide), poly(L‐lactide‐co‐glycolide‐co‐ε‐caprolactone), and poly(lactide‐co‐ε‐caprolactone) monofilaments exhibited good tensile strengths and elongations at break in the first four weeks, which were reduced to almost zero in the eighth week. Ureteral stents made of these polymers can open narrow urethras at early stages and degrade completely at later stages. Based on its degradation rate, we conclude that the poly(lactide‐co‐ε‐caprolactone) monofilament is the best material for the preparation of ureteral stents. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries on electric vehicles have been increasingly deployed for the enhancement of grid reliability and integration of renewable energy, while users are concerned about extra battery degradation caused by vehicle-to-grid (V2G) operations. This paper details a multi-year cycling study of commercial 24 Ah pouch batteries with Li(NiMnCo)O2 (NCM) cathode, varying the average state of charge (SOC), depth of discharge (DOD), and charging rate by 33 groups of experiment matrix. Based on the reduced freedom voltage parameter reconstruction (RF-VPR), a more efficient non-intrusive diagnosis is combined with incremental capacity (IC) analysis to evaluate the aging mechanisms including loss of lithium-ion inventory and loss of active material on the cathode and anode. By analyzing the evolution of indicator parameters and the cumulative degradation function (CDF) of the battery capacity, a non-linear degradation model with calendar and cyclic aging is established to evaluate the battery aging cost under different unmanaged charging (V0G) and V2G scenarios. The result shows that, although the extra energy throughput would cause cyclic degradation, discharging from SOC 90 to 65% by V2G will surprisingly alleviate the battery decaying by 0.95% compared to the EV charged within 90–100% SOC, due to the improvement of calendar life. By optimal charging strategies, the connection to the smart grid can potentially extend the EV battery life beyond the scenarios without V2G.

Biochemical and biomolecular archaeology is increasingly used to elucidate the consumption, use, origin, and trade of plants in the past. However, it can be challenging to use biomarkers to identify the taxonomic origin of archaeological plants due to limited knowledge of molecular survival and degradation for many key plant compounds in archaeological contexts. To gain a fundamental understanding of the chemical alterations associated with chemical degradation processes in ancient samples, we conducted accelerated degradation experiments with essential oil derived from cedar (Cedrus atlantica) exposed to materials commonly found in the archaeological record. Using GC-MS and multivariate analysis, we detected a total of 102 compounds across 19 treatments that were classified into three groups. The first group comprised compounds that were abundant in fresh cedar oil but would be unlikely to remain in ancient residues due to rapid degradation. The second group consisted of compounds that remained relatively stable or increased over time, which could be potential biomarkers for identifying cedar in archaeological residues. Compounds in the third group were absent in fresh cedar oil but were formed during specific experiments that could be indicative for certain storage conditions. These results show that caution is warranted for applying biomolecular profiles of fresh plants to ancient samples and that carefully designed accelerated degradation experiments can, at least in part, overcome this limitation.

Solenoid valves (SVs) are used as actuators in various applications, which are crucial parts in control system. Their failure may result in a system crash, so its health condition and reliability are related to the safety of an engineering system. In order to explore the basis of condition-based maintenance or replacement of SVs, it is necessary to develop a prognostic approach to predict its operation condition and remaining useful life (RUL). In this paper, a particle filter (PF) technique, an online tracking method, is proposed to make prognostics for SV. Moreover, the Brownian motion degradation model is proposed, and the distortion of dynamic driven current curve is assumed as the indicator of degradation state. To validate the proposed PF-based prognostics method, a degradation experiment is designed. The result shows that the predicted degradation state accurately reflects the real time filtered degradation state of SV and a good RUL prediction can be calculated by this method. [ABSTRACT FROM AUTHOR]

2-(2′-hydroxy-5′-methylphenyl) benzotriazole (UV–P) is a type of emerging persistent organic pollutant that is reported harmful to organisms. However, its degradation mechanisms and transformation behaviors in aquatic environments are not yet clear, which are significant for better understanding its environmental fate and potential toxicological impacts. In present work, the degradation mechanisms, kinetics, half-life times and eco-toxicity assessment of UV-P initiated by hydroxyl radical (•OH), sulfate radical (SO 4 •‾), and singlet oxygen (1O 2) are systematically studied using density functional theory (DFT) and experimental methods. The initiated reaction results show that benzene ring of UV-P is vulnerable to attack by •OH, while benzotriazole is easily attacked by SO 4 •‾. The kinetic calculations indicate that •OH-addition reaction R15 is dominant initial pathway. And the half-life (t 1/2) of UV-P is calculated according to rate constants, t 1/2 decreases rapidly with [ROS] increasing. UV-P exhibits environmental persistence when [•OH] ≤ 10−17 M. The subsequent degradation mechanisms of hydroxylated UV-P react with •OH and O 2 are also calculated. A novel ring-opening reaction channel is proposed that O 2 -addition intermediate combines with hydroperoxyl radical (HO 2 •) to cleave aromatic ring. The rate-determining step is intramolecular dehydration reaction with the energy barrier of 32.98 kcal mol−1 and 41.13 kcal mol−1 to cleave benzene ring and benzotriazole ring, respectively. The degradation experiments of UV-P are conducted in Co 3 O 4 activated potassium peroxymonosulfate (PMS) system, and liquid chromatograph-mass spectrometer (LC-MS) results identified that dihydroxylated species are main intermediates, which is consistent with theoretical calculation results. Furthermore, the eco-toxicity assessment shows that the acute and chronic toxicities of most degradation products are reduced compared with UV-P, however, their toxicity levels still keep at toxic and harmful. The environmental risk of UV-P deserves more attention. [Display omitted] • UV-P is easily initiated by.•OH and SO 4 •‾ through •OH/SO 4 •‾-addition reactions. • Hydroxylated UV-P react with ROS to cleavage aromatic ring. • The environmental persistence of UV-P decreases rapidly with [ROS] increasing. • UV-P and some oxidation products are toxic to aquatic organisms. [ABSTRACT FROM AUTHOR]

In order better to interpret the chemical composition of ancient organic residues and artefacts containing beeswax, the degradation of this raw material was accelerated in the laboratory by controlled heating. During the course of degradation, deposits were condensed above the beeswax. Both degraded beeswax and these deposits were analysed. These experiments definitively proved that n-alkane depletion is due to a sublimation process that depends on the molecular weight of these hydrocarbons. The formation of benzoic and cinnamic derivatives due to the degradation of flavonoid precursors initially present in beeswax has also been highlighted for the first time. The analysis of samples from Neolithic and Roman periods led to the identification of beeswax characterized by different degradation patterns linked to their environmental context. [ABSTRACT FROM AUTHOR]