The increasing demand for rare earth elements (REEs) in modern applications has drawn significant attention. REEs can be introduced into the environment through REE-containing fertilizers, abandoned REE-rich equipment...
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The increasing demand for rare earth elements (REEs) in modern applications has drawn significant attention. REEs can be introduced into the environment through REE-containing fertilizers, abandoned REE-rich equipment, and mining, persisting and impacting soil quality, nutrient cycles, and plant growth. Scientists have raised concerns about REEs entering the food chain from the environment and eventually accumulating in organisms. Decades of experimental evidence have shown that these effects include inhibited growth, impaired liver function, and alterations in children's intelligence quotients. However, there exists a paucity of research that has elucidated the metabolic-level biological impacts of REEs. In our study, caenorhabditis elegans (c. elegans) was used as a model organism to investigate physiological and inherent metabolicchanges under exposure to different concentrations of REEs. The diet bacteria of nematodes play a key role in their life and development. Therefore, we investigated the influence of bacterial activity on the nematodes' response to REE exposure. We observed a concentration-dependent accumulation of REEs in nematodes, which consequently led to a reduction in lifespan and alterations in body length. Exposure to a mixed solution of REEs, in comparison to a single REE solution, resulted in greater toxicity toward nematodes. The metabolic results showed that the above changes were closely related to REE-induced amino acid metabolism disorder, membrane disturbance, DNA damage, and oxidative stress. Of note, the presence of living bacteria elicits REE effects in c. elegans. These findings highlight the potential intrinsic metabolicchanges occurring in nematodes under REE exposure. Our study raises awareness of the exposure risks associated with REEs, provides valuable insight into the metabolic-level biological impacts of REEs and contributes to the development of effective mitigation strategies to reduce potential risks to human health.
Silicon (Si) has been proven to be the most potential anode material for the next-generation lithium-ion batteries (LIBs) because of its superior theoretical capacity (similar to 4200 mAh g-1). However, the huge volum...
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Silicon (Si) has been proven to be the most potential anode material for the next-generation lithium-ion batteries (LIBs) because of its superior theoretical capacity (similar to 4200 mAh g-1). However, the huge volume changes, unstable solid-state interphase (SEI) layers, and large internal stresses upon the lithiation process severely limit the practical application for commercial LIBs anodes. Herein, we fabricate the carbon-coated Si/FeSi2 nanoparticles (Si/FeSi2 @c NPs) with volume control effect by fluidized bed chemical vapor de-position (FBcVD) method to solve the above-mentioned problems. These 15 min-Si/FeSi2 @c NPs and 30 min-Si/FeSi2 @c NPs show excellent Li+ storage capacity in the first cycle (2705.9/3039.1 mAh g-1 and 2645.9/2984.2 mAh g-1) with high Initial coulombic Efficiency (IcE) of similar to 89.0% and 88.7%. In-situ TEM characterization demonstrates that the carbon coating layer and inert FeSi2 phase enable a small volume variation, only similar to 37.8%, revealing the effective volume expansion control effect, and generating thin SEI layers. Besides, the perfect structure of Si/FeSi2 @c NPs makes this material a great improvement in rate performance.(c) 2022 Elsevier B.V. All rights reserved.
This article considers an inverse problem for a cosserat rod where we are given only the position of the centreline of the rod and must solve for external forces and torques as well as the orientation of the cross sec...
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This article considers an inverse problem for a cosserat rod where we are given only the position of the centreline of the rod and must solve for external forces and torques as well as the orientation of the cross sections of the centreline. We formulate the inverse problem as an optimal control problem using the position of the centreline as an objective function with the external force and torque as control variables, with meaningful regularisation of the orientations. A monolithic, implicit numerical scheme is proposed in the sense that primal and adjoint equations are solved in a fully-coupled manner and all the nonlinear coefficients of the governing partial differential equations are updated to the current state variables. The forward formulation, determining rod configuration from external forces and torques, is first validated by a numerical benchmark;the solvability and stability of the inverse problem are then tested using data from forward simulations. The proposed optimal control method is motivated by reconstruction of the orientations of a rod's cross sections, with its centreline being captured through imaging protocols. As a case study, we take the locomotion of the nematode, caenorhabditis elegans. In this study we take laboratory data for its centreline and infer its cross-section orientation (muscle locations) with the control force and torque being interpreted as the reaction force, activated by c. elegans' muscles, from the surrounding fluids. This method thus combines the mathematical modelling and laboratory data to study the locomotion of c. elegans, which gives us insights into the potential anatomical orientation of the worm beyond what can be observed through the laboratory data. The paper is completed with several additional remarks explaining the theoretical and technical details of the model.
Due to the high speed and high pressure operating conditions, wear between the finger seal and the rotor is inevitable, and this leads to an increase of leakage clearance and becomes an important factor affecting the ...
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Due to the high speed and high pressure operating conditions, wear between the finger seal and the rotor is inevitable, and this leads to an increase of leakage clearance and becomes an important factor affecting the seal life. The theory of anisotropic elasticity was employed to describe the mechanical characteristics of the seal material. An improved Archard wear model was proposed to calculate the nodal wear rate, and the local wear direction was also determined. The wear simulation model and procedure were established based on the Arbitrary Lagrangian Eulerian adaptive mesh strategy. The effects of material density, fabric orientation, pressure differential and rotor speed on the wear characteristics of finger seal and the change of leakage clearance caused by wear loss were studied. The results show that the wear first occurs at the heel area of the finger foot bottom and gradually extends to the toe area. c/c (carbon fibre reinforced carbon matrix) composite finger seal with higher material density has smaller leakage clearance and wear depth. With the increase of fabric orientation angle, the wear depth in the heel area of finger foot is smaller, and the circumferential wear area is narrower. The average wear depth of finger seal decreases with the orientation angle. When the orientation angle is 0, the seal leakage clearance is smaller. The increase of pressure differential not only aggravates the seal wear, but also expands the wear area, and also increases the average contact pressure and leakage clearance. Increasing the rotor speed make the wear depth of the heel area of finger foot gradually increase, but the wear area becomes narrower. The average contact pressure decreases and the average leakage clearance increases. This study provides a theoretical method and basis for the prediction and evaluation of the wear life and performance of c/ccomposite finger seal.
coP has attracted increasing attention due to its high theoretical capacity for lithium storage. However, coP suffers from a large volume expansion during cycling, which leads to electrode pulverization and poor cycle...
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coP has attracted increasing attention due to its high theoretical capacity for lithium storage. However, coP suffers from a large volume expansion during cycling, which leads to electrode pulverization and poor cycle stability. In addition, the conductivity of coP is poor, resulting in undesirable rate performance. To solve this problem, the coP/ccomposite was prepared based on the in-situ phosphating heat treatment technology of co-BTc MOF. The as prepared coP/c exhibits a good lithium storage specificcapacity and a cycle stability, which is attributed by the synergistic effect of the porous nanostructure and carbon frame. The porous nanostructure of the coP/c allows the electrolyte to easily penetrate into the interior, which increases the number of electrochemical reaction sites while effectively mitigating the volume expansion during lithiation and improving electrical conductivity. Thanks to the special structures, the discharge specificcapacity of the Lithium-ion batteries (LIBs) based the coP/c as anode materials is 645.7 mAh g(-1) after 200 cycles at a current density of 200 mA g(-1). This work demonstrates that the coP/c has a great potential as a next generation anode material for LIBs.
Lithium-ion batteries (LIBs) fatigue in repeated service, and their cycle-life, in resemblance to most materials subject to cyclic loading, scatters over a broad range. The dependence of critical fatigue parameters on...
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Lithium-ion batteries (LIBs) fatigue in repeated service, and their cycle-life, in resemblance to most materials subject to cyclic loading, scatters over a broad range. The dependence of critical fatigue parameters on ambient temperature and charging or discharging rate, along with the scattering nature of cycle-life is of practical significance. Through large-scale experimental investigations, it is shown how both temperatures and charging-discharging rates may influence critical parameters in the c - N fatigue dependence for LIBs. The cycle-life N of a battery subject to an average charging rate c follows c = c(0) (T)N-b(D), where c(0) varies with temperature T and b is a function of the discharging rate D. It is further shown that the cycle-life of LIBs follows a lognormal distribution. The revealed cycle-life distribution of LIBs and their fatigue law enable the construction of a probabilisticc - N model, which can be used to quantify the fatigue failure probability in LIBs. Results reported here are of compelling importance for the life-span evaluation and safety design of large-scale battery packing in electric vehicles and energy storage where tens of hundreds of batteries working in concert is desired.
A series of Ag-0@c/SiO2 adsorbents were prepared using rice husk-based c/SiO2 as supports and applied to capture iodine gas. The results demonstrated that 50%Ag-0@c/SiO2 reached a record high iodine adsorption capacit...
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A series of Ag-0@c/SiO2 adsorbents were prepared using rice husk-based c/SiO2 as supports and applied to capture iodine gas. The results demonstrated that 50%Ag-0@c/SiO2 reached a record high iodine adsorption capacity (788 +/- 25 mg/g) due to the synergistic effect between c/SiO2 supports and Ag-0 sites. The adsorption data of Ag-0@c/SiO2 can be better fitted with the pseudo first order and Langmuir models. The iodine adsorption process included the physical and chemical adsorption. The adsorption mechanism was that Ag-0 reacted with I-2 to form AgI. Owing to the excellent adsorption capacity, Ag-0@c/SiO2 derived from rice husk could be promising iodine gas adsorbents.
carbon fiber/phenolic resin composites (cF/Ph) have attracted great interests in the field of thermal protection materials for their characteristics of high specific strength and easy manufacturing. However, cF/Ph are...
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carbon fiber/phenolic resin composites (cF/Ph) have attracted great interests in the field of thermal protection materials for their characteristics of high specific strength and easy manufacturing. However, cF/Ph are inherently susceptible to oxidation failure at elevated temperatures. In this study, a novel Al-coated carbon fiber/ boron phenolic resin ceramizable composite modified with TiB2 and B4c was fabricated by an impregnating and compression molding route. Thermal stability, flexural strength, microstructure and phase evolution of the resulting ceramizable composite were studied. The residue yield at 1400 degrees c and flexural strength after treated at 1400 degrees c for 15min was 90.4% and 53.1 MPa, respectively, which was increased by 15.9% and 532.1% than that without ceramizable fillers. Surface defects generated by matrix pyrolysis were well healed, and Pyc and carbon fibers were covered with dense ceramic layers while the fracture surface was covered with relatively continuous ceramic layers without visible pores. Multiphase ceramics composed of TiB2, TiO2, Tic and Pyc were identified. Furthermore, oxidation failure and anti-oxidation mechanism was revealed based on the aforementioned characterizations and thermodynamiccalculation results. Oxidation resistance got enhanced markedly for synergistic effects of oxygen consuming, carbon fixation, oxygen barrier and endothermic effect, which were derived from ceramization reactions between TiB2, B4c, O2, Al and Pyc.
Obtaining coatings with excellent ablation resistance is a longstanding challenge for the ablation protection of carbon/carbon (c/c) composites. In this work, a single phase Hf0.75Zr0.25N solid solution ultra-high tem...
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Obtaining coatings with excellent ablation resistance is a longstanding challenge for the ablation protection of carbon/carbon (c/c) composites. In this work, a single phase Hf0.75Zr0.25N solid solution ultra-high temperature ceramic (UHTc) coating was proposed, and prepared on the surface of c/ccomposites by chemical vapor deposition (cVD) for the first time. The results revealed that the hardness and Young's modulus of Hf0.75Zr0.25N coating are higher than those of HfN and ZrN coatings, reaching 33.35 GPa and 316.42 GPa, respectively. After ablation for 180 s under oxygen acetylene flame with a temperature exceeding 2200 & DEG;c, the Hf0.75Zr0.25N coating retained its structural integrity and exhibited lower ablation (Rm: 0.26 mg/s;Rh: 0.32 & mu;m/s). This is mainly attributed to the formation of the dense Hf-Zr-O oxide scale promoted by the oxidation sintering reaction during ablation. The above results indicate the nitride solid solution UHTc has great potential as ablation resistance coating at ultra-high temperatures.
constructed wetlands with microbial fuel cells (MFc-cWs) are widely acknowledged to be efficient in pollutant removal, and have been reported to be beneficial in reducing specific gaseous emissions. However, as a crit...
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constructed wetlands with microbial fuel cells (MFc-cWs) are widely acknowledged to be efficient in pollutant removal, and have been reported to be beneficial in reducing specific gaseous emissions. However, as a critical parameter that directly addresses, the behavior of carbon (c) and nitrogen (N), the impact of the influent c/N ratio on the comprehensive performance of MFc-cWs remains unknown. Herein, the impact of c/N ratios (i.e., 1, 5, 10, 15) on pollutants (cOD, symbolscript NO3--N, NO2--N, TN and TP) removal, multiple gaseous (cO2, cH4, N2O and NH3) emissions and electricity generation of MFc-cWs were evaluated, and the internal mechanisms were explored. Increasing the c/N ratio enhanced cOD removal, and the MFc-cWs achieved superior symbolscript TN, and TP removal efficiencies at c/N ratios of 5 and 10. The higher c/N ratio was generally accompanied by greater cO2, cH4, and NH3 fluxes. Nevertheless, the lowest global warming potential (GWP) was observed at c/N of 5 due to the lowest N2O flux having been obtained. The functional gene analysis results showed that the decrease in N2O flux was attributed to an increase in the nosZ/(nirS symbolscript nirK) ratio, and the cH4 flux was regulated by the abundance of pomA and mcrA genes. The highest power density (152.54 mA/m3) and current intensity (649.03 mW/m3) were also observed in MFc-cWs with a c/N ratio of 5, mainly due to the increase in electrogenic bacteria (e.g., Proteobacteria and Firmicutes). consequently, the influent c/N ratio of 5 was optimal for treating wastewater and generating electricity efficiently, and also attenuating the corresponding GWP in MFc-cWs.
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