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The lithium–sulfur battery is considered to be one of the most promising rechargeable energy storage systems because of its high theoretical energy density. Unfortunately, the shuttle effect during cycling causes serious loss of sulfur species and corrosion of the lithium metal anode, resulting in severe capacity decay. This work proposes to completely suppress the shuttle effect of lithium polysulfides (LiPSs) without sacrificing the interfacial Li+ transport, through in situ construction of a compact cathode electrolyte interphase (CEI), which is formed of the reaction between vinylene carbonate (VC), bis(trifluoromethane)sulfonimide ions and LiPSs in a self‐limiting manner during the initial discharge process. Hence, the CEI‐confined sulfur cathode in the VC‐based electrolyte with a solid phase conversion mechanism delivers a long‐term cycling stability and high‐rate performance, as well as excellent performance under an extreme climate in a subzero temperature of −20 °C, limited lithium source with a low N/P ratio of 1.1, and even at mechanical mutilation. The present study reveals an appealing approach to tailor the composition and interfacial structure of sulfur cathodes by in situ construction of a robust, self‐healing, and high Li+ conductive CEI from the aspect of electrolyte, and thus completely solve the issue of the shuttle effect. [ABSTRACT FROM AUTHOR]

[Display omitted] Sodium-ion batteries, featuring resource abundance and similar working mechanisms to lithium-ion batteries, have gained extensive interest in both scientific exploration and industrial applications. However, the extremely sluggish reaction kinetics of charge carrier (Na+) at subzero temperatures significantly reduces their specific capacities and cycling life. Herein, this study presents a novel hybrid structure with sodium titanium phosphate (NaTi 2 (PO 4) 3 , NTP) nanocube in-situ decorated on tablet-like carbon (NTP/C), which manifests superior sodium storage performances at low temperatures. At even −25 °C, a stable cycling with a specific capacity of 94.3 mAh/g can still be maintained after 200 cycles at 0.5 A/g, delivering a high capacity retention of 91.5 % compared with that at room temperature, along with an excellent rate capability. Generally, the superionic conductor structure, flat voltage plateaus, as well as the conductive carbonaceous framework can efficiently facilitate the charge transfer, accelerate the diffusion of Na+, and decrease the electrochemical polarization. Moreover, further investigations on diffusion kinetics, solid electrolyte interface layer, and the interaction between NTP and carbonaceous skeleton reveal its high Na+ diffusion coefficient, robust solid electrolyte interface, and strong electronic interaction, thus contributing to the superior capacity retentions at subzero temperatures. [ABSTRACT FROM AUTHOR]

This paper studies the influence of mechanical tensile loads in the range of 0–300 MPa on the nature of γ → α transformation in cold-rolled maraging steel in the temperature range of –20...–60°С. Based on the kinetic curves of the electrical resistance, critical temperatures Mbeg and Mend were determined and the diagrams of the isothermal decomposition of supercooled retained austenite annealed in the two-phase region after two cycles at a temperature of 650°C for 6 h were plotted. It has been established that mechanical loads in the range of 20–300 MPa affect the parameters of the gamma-alpha transformation ambiguously, shifting the isothermal diagrams in temperature and time and significantly changing the stability characteristics of austenite. Resistance of austenite to supercooling Ts varies from –25 to –55°С, incubation period τinc from 2 to 8 min, and decay period τdec with two extremes (50 and 100 MPa) from 51 to 518 min depending on the load level. The recorded maximum duration of the annealing austenite decomposition at low loads (20–100 MPa) is explained by the structural and chemical inhomogeneity of the phases, as well as the stress level of the initial state of the samples under study. The threshold stress is determined, loading up to which leads to a decrease by ∼15°С in the beginning of the γ → α transformation in the interval of subzero temperatures (from –40° to –55°C). It can be assumed that the shift of the diagrams to the range of low temperatures is due to a change in the mechanism of the γ → α transformation. It is shown that cyclic heat treatment in the two-phase region at a temperature of 650°C for 6 h at loads up to 100 MPa delays the isothermal decomposition of supercooled retained austenite in the steel under study. [ABSTRACT FROM AUTHOR]

The working life of a stack is basically determined by the behavior of its weakest monomer; therefore, during a dynamic loading process, high-voltage uniformity plays a key role in stack durability. This work experimentally investigated dynamic responses and voltage uniformity with different loading strategies from an initial state (open-circuit state) to a target current at subzero temperatures. The results presented that the maximum voltage coefficient variation Cv values, representing the relative standard deviation of the monomer voltage, increased from 19.75 to 35.65 and the voltage uniformity sharply decreased with the increase in loading sizes at the stack temperature of −4 °C. It was possible that this could result in the instability of the single cell voltage output and a voltage uniformity fluctuation with a high step loading amplitude. The voltage uniformity became worse as the stack temperature decreased from −2 °C to −8 °C, the voltage uniformity between single cells of the stack continued to deteriorate under a step current density of 0.15 A/cm2 at a relatively low temperature of −8 °C. By comparing several constant loading rate strategies, it could be ascertained that reducing the loading rate was conducive to voltage uniformity in the whole investigated process. A comparison of the different loading rates indicated that the square increasing loading rate strategy is the best strategy among them and a Cv threshold of 5.5 can be obtained during the whole load process at a temperature of −4 °C, which might be a guideline and provide a reference in actual engineering applications for PEMFC dynamic loading responses. [ABSTRACT FROM AUTHOR]

In this paper, the γ → α transformation kinetics in cold-rolled maraging steel is studied in the temperature range of 0...–100°C. Based on electrical-resistivity kinetic curves R = f(τ), critical temperatures Mbegin and Mend have been determined and isothermal transformation diagrams have been constructed for overcooled retained austenite formed during annealing and quenching with preliminary annealing. It is shown that the martensitic γ → α transformation of retained austenite formed during annealing in the two-phase (α + γ) region at the temperature of 500°C during 50 h, which is close to the critical temperature Abegin, takes place in the temperature range of –8...–16°C; the temperature of the minimal stability (the "nose" of the C-curve) is –12°C, at which the incubation period is 4 min and the transformation period is 11 min. The martensitic γ → α transformation of retained austenite formed during quenching with preliminary annealing takes place in the temperature range of –86...–96°C. In this case, the incubation period increases by more than a factor of 10 and the transformation period increases by more than a factor of 8. The maximal shift of the diagrams to the side of low temperatures is ~80°C and is not associated with the preliminary annealing influence since the stability characteristics of retained austenite of quenching with preliminary annealing and without it are similar. The shift of the diagrams to the side of low temperatures is due to the processes occurring at heating for quenching, and according to the resistometry results, preliminary annealing does not influence the above processes. [ABSTRACT FROM AUTHOR]

Psychrotolerant microbes are crucial for carbon cycling and biotechnological applications. Nonetheless, the mechanisms enabling their survival and functioning in frozen environments remain unclear. To elucidate adaptations of microbial cell membranes to freezing, we incubated soils with position-specific 13C labeled glucose at + 5 (control), − 5 and − 20 °C and quantified 13C in CO2 and phospholipid fatty acids. High oxidation of glucose C-1 at + 5 °C revealed a transformation via the pentose phosphate pathway. At subzero temperatures, however, the preferential oxidation of C-4 position suggested a switch to glycolysis. The threefold increase of Gram-negative phospholipid fatty acids in soil incubated at − 5 °C was accompanied by a twofold increase in 13C incorporation. This unequal increase of phospholipid fatty acids and incorporated 13C can be explained by simultaneous desaturation of existing fatty acid chains and the de novo synthesis of monounsaturated fatty acids, which indicates microbial growth. In contrast, Gram-positive bacteria incorporated 2 times higher 13C into their phospholipid fatty acids at − 20 °C than at − 5 and + 5 °C without a significant increase in their fatty acid contents. This reflects intensive repair of membranes damaged at − 20 °C without microbial growth. The fungal/bacterial ratio was 1.5 times lower at subzero temperatures than at + 5 °C, reflecting a shift in microbial community structure towards bacteria. Accordingly, soil microorganisms adapted to freezing by (1) switching their metabolic pathway from the pentose phosphate pathway to glycolysis, (2) modifying phospholipid fatty acids by desaturation and, (3) shifting microbial community structure towards Gram-negative bacteria by reducing the fungal population. [ABSTRACT FROM AUTHOR]

The flexural behavior of the 3D integrated woven spacer composites with carbon fiber-reinforced polymer face sheets are performed with epoxy and polyester matrix in the warp direction. The static loading of foam core carbon/epoxy and carbon/polyester composite sandwich panels in three-point flexural test was characterized at room temperature (23℃) and at liquid nitrogen temperature (−40℃). Macro-fracture morphology and progress have been examined to understand the deformation and failure mechanism. Significant increases in the flexural strength with brittle type core shear failure were observed at low temperatures as compared with the corresponding room temperature behavior. The performance of the epoxy-based composite is compared to the polyester one. Significant changes in the flexural properties of the composites have been found, first related to the temperature and then to the resin type. The flexural properties of the epoxy-based composites were affected greatly by temperature and exhibited higher flexural performance than polyester-based composites at low temperatures. [ABSTRACT FROM AUTHOR]

Parameters leading to the severe Flatanger and Frøya (Norway) January 2014 subzero wildfires, respectively burning 15 km 2 and 10 km 2 Atlantic heathlands (dominated by heather, Calluna vulgaris ) and destroying 64 structures, have been analyzed. Traditional heathland management, including anthropogenic fire regimes, had not been performed in these areas over the last 50+ years. As a result, the vegetation composition consisted of degenerated old and woody Calluna stands, bushes and shrubs, with high amounts of accumulated (live and dead) biomass. Adiabatically heated subzero temperature easterlies dried the Calluna stands. When ignited, the lack of snow cover and the strong winds resulted in rapid fire spread. Rugged terrain, few hours of daylight at 64.4°N and the lack of roads and manmade fire lanes made controlling the fires very challenging. Drying experiments were conducted to learn how quickly Calluna plants dry at 20°C and 50% relative humidity from rain-wet conditions. Based on the surprisingly rapid drying of the lower (dead) canopy, vapor pressures and diffusion theory, it is concluded that the Flatanger and Frøya Calluna stands represented a severe fire risk within two days of exposure to 50% relative humidity air at 0°C. Young and more vigorous plants in the building phase (6–15 years old), as well as freeze drought damaged (typically some dead small branches) old but still live plants, showed different drying characteristics and dried more slowly. When understanding how degenerated Calluna stands, from Portugal to the Arctic Circle, dry in the wintertime, warnings may be issued when appropriate. This paper may also serve as input to discussions regarding the several-thousand-year tradition of prescribed burning versus potential raging wildfires in unmanaged Calluna stands. [ABSTRACT FROM AUTHOR]

This paper presents a thermal analysis of a semi-active battery/supercapacitor (SC) hybrid energy storage system (HESS), which is used in electric vehicles (EVs), at subzero temperatures. In subzero temperature environments, EVs suffer a dramatic driving range loss due to the energy and power capability reduction of LiFePO 4 batteries, as well as severe battery degradation due to Li plating. This will increase the system operation cost because the battery pack needs to be changed frequently. Based on a novel degradation model of LiFePO 4 batteries, which is validated over a wide temperature range, a near-optimal energy management strategy of the HESS for on-line use is proposed using the dynamic programming (DP) approach, which minimizes the operation cost (the electricity and the battery fade costs) over a typical China Bus Drive Cycle (CBDC). The convective heating method is integrated into the DP process. Finally, the required heating of the HESS at subzero temperatures over multi-CBDC is analyzed by evaluating the system operation cost. Simulation results show that the heating process becomes increasingly necessary with increased driving range, battery price, and heating efficiency, as well as decreasing environment temperature. [ABSTRACT FROM AUTHOR]

In a previous study, we numerically described the three distinct stages of ice evolution during the cold start of a polymer electrolyte fuel cell (PEFC), namely, the freezing, undersaturated, and melting stages. Based on our numerical observations, we propose an efficient start-up strategy for achieving a rapid cell temperature rise while simultaneously mitigating the rate of ice accumulation within a cell. The key to this cold-start strategy involves raising the operating current of the PEFC in the undersaturated stage, which accelerates the cell temperature rise without any further ice accumulation. Using a three-dimensional, transient cold-start model, we numerically demonstrate that raising the cell current in the undersaturated stage is very effective and significantly improves the cold-start behavior of a PEFC. In contrast, increasing the cell current in the freezing stage has a negative impact on the PEFC cold start in that the oxygen reduction reaction causes the water production rate to increase, leading to more rapid ice growth. This ultimately results in cold-start failure and the deterioration of the porous electrode structure. This study clearly illustrates that optimization of the cold-start operation is key to improving the cold-start performance, while also pointing to the importance of the roles played by PEFC cold-start modeling and the simulations used to search for an optimum cold-start strategy. [ABSTRACT FROM AUTHOR]

Conducting enzymatic stopped-flow experiments at temperatures far removed from ambient can be very problematic because extremes in temperature (<10 °C or >30 °C) can damage the machine or the enzyme. We have devised a simple manifold that can be attached to most commercial stopped-flow systems that is independently heated or cooled separate from the main stopped-flow system. Careful calibration of the flow circuit allows the sample to be heated or cooled to the measurement temperature (−8 to +40 °C) 1 to 2 s before mixing in the reaction chamber. This approach allows measurements at temperatures where the stopped flow or the protein is normally unstable. To validate the manifold, we investigated the well-defined ATP-induced dissociation of rabbit muscle myosin subfragment 1 (S1) from its complex with pyrene-labeled actin. This process has both temperature-dependent and -independent components. Use of ethylene glycol allowed us to measure the reaction below 0 °C and up to 42 °C, and as expected the second-order rate constant ( K 1 k +2 ) and the maximum rate of dissociation ( k +2 ) both increased with temperature, whereas 1/ K 1 is unaffected by the change in temperature. [ABSTRACT FROM AUTHOR]

Highlights: [•] Fracture tests were conducted under mixed I/II loading using an improved SCB specimen. [•] Both loading mode and temperature affect the fracture behavior of asphalt concretes significantly. [•] Depending on loading mode, SBS copolymer improves fracture resistance of asphalt concrete at lower temperatures. [•] Asphalt concretes are more vulnerable to fracture under mixed mode I/II loading than pure mode I or II. [ABSTRACT FROM AUTHOR]

Abstract: Soil/air partition coefficients (K SA) were measured experimentally on a silty clay loam soil spiked with polychlorinated biphenyls (PCBs) over a wide range of environmentally relevant temperatures (−30 to +30°C). Measured K SA-values ranged over 6.4 orders of magnitude, with log K SA from 4.3 for PCBs 10/4 at +30°C to 10.7 for PCBs 77/110 at −30°C. Higher than expected, K SA-values were observed at subzero temperatures (by up to one order of magnitude, at −30°C). The plots of log K SA vs. reciprocal absolute temperature show a change in slope at 0°C. A log–log linear regression of K SA vs. octanol/air partition coefficient (K OA) has a slope close to 1, indicating that K OA is a good descriptor of the interchemical variability in K SA. Further study showed that K OA-based Karickhoff-type equations can perfectly fit experimental K SA-values. [Copyright &y& Elsevier]

Abstract: We have developed a simple and sensitive method to detect microbial respiration at subzero temperatures. Microbial activity was detected by measuring 14CO2 evolved during the microbial-mediated mineralization of [1-14C] acetic acid or [2-14C] glucose in microcosm assays using modified 14CO2 traps. Various 14CO2 traps, designed to withstand freezing at subzero temperatures, were tested for their quench characteristics during liquid scintillation spectrometry and their ability to trap 14CO2. Solutions consisting of 1 M KOH supplemented with 20% or 30% v/v ethylene glycol did not freeze at temperatures above −20 °C and had a minor quenching effect on liquid scintillation spectrometry. Addition of ethylene glycol did have an effect on the efficiency of 14CO2 trapping, as the cumulative recovery of 14CO2 was reduced by 14% and 32% in the 1 M KOH+20% ethylene glycol and 1 M KOH+30% ethylene glycol solutions, respectively. Using the modified 14CO2 traps, microbial activity in representative Canadian high Arctic environmental samples was detected at temperatures as low as −15 °C. This simple method allows for sensitive, specific, and reliable detection of microbial activity occurring at subzero temperatures and is readily adaptable for studies in other cryoenvironments. [Copyright &y& Elsevier]

To understand in situ properties of ice under pressure, we need an accurate model for ice compressibility. Many studies have estimated ice compressibility, but there still remains considerable controversy with respect to the magnitude and temperature dependence of ice compressibility. The specific objectives of this study were to (1) present a new model for estimating the compressibility of ice based on chemical thermodynamic principles, and (2) compare these model results with previous work.A thermodynamic equation that relates equilibrium constants to molal volumes and compressibilities of water and ice was the basic model used to estimate ice compressibilities. All terms in this equation (equilibrium constants, temperature, pressure, molal volumes of ice and water at 1 atm, and water compressibilities) are definable along the pressure ice/water melting curve except for ice compressibility, which we estimated from the equation.Our estimate of ice compressibility demonstrated a significant temperature dependence. In contrast, most other studies, especially those that rely on elastic parameters, only demonstrate a weak temperature dependence. All recent studies show a significantly lower ice compressibility than the classic Bridgman studies.The results of this work are in agreement with most other databases and models and indicate a general consensus on the compressibilities of water and ice up to 1200 bar of pressure. Between 1200 and 2000 bar, there are discrepancies that are unlikely to be resolved without further experimental work that directly estimate the compressibility of ice over a range of temperatures.A comparison of calculated ice core densities from Antarctica, with and without corrections for pressure, demonstrate the utility of this model for understanding in situ ice properties under pressure. [Copyright &y& Elsevier]

• Epoxy and polyester based 3D woven spacer composites were fabricated successfully. • Two, three, and four layered carbon fiber face-sheets were used. • The flexural behavior for warp and weft core direction was investigated at subzero temperature. • The morphology of fracture was observed from the macroscopic views of the sandwich composites. The present work aims at characterizing the 3D woven spacer composites with carbon fiber reinforced polymer face-sheets under the 3-point flexural test at subzero temperature conditions. For this purpose, sandwich composite panels are manufactured using vacuum assisted resin infusion method for epoxy and polyester matrix materials with 2, 3, and 4 layered face-sheets. The 3-point flexural test was performed for warp and weft direction on liquid nitrogen temperature (−40 °C). Macroscopic fracture morphology was examined to understand the deformation and failure mechanism. The results show that the flexural properties were significantly affected by the number of face-sheets and then from matrix material and finally from the composite direction at subzero temperatures. [ABSTRACT FROM AUTHOR]