Low Temperature Environment Research Articles

Magnetically driven droplet manipulation on a smart surface prepared by electrospinning

Droplet manipulation using a magnetic field has vital applications in nanomaterials synthesis, lab-on-a-chip, and other domains. To address the separation issue between the droplet and the magnetic particle following the manipulation process, electrospinning technology was used to create a thermosensitive surface with changeable hydrophilicity. The droplet manipulation in this investigation could be divided into three steps: Step 1, the iron shot entered the droplet; Step 2, the iron shot carried the droplet forward; Step 3, the iron shot exited the droplet. The experimental findings revealed that a part of the iron shots could carry droplets with varying sizes when a magnetic field was activated. At the same time, droplet manipulation would be difficult employing high velocity iron shot movement or in a low temperature environment. Further investigation revealed two conditions for successful droplet manipulation. Firstly, the diameter of the iron shot had to be large enough to create adequate capillary force. Secondly, the hysteresis force between the droplet and the smart surface changed with the alteration of the hydrophilicity of the smart surface. More experiments indicated that the proposed droplet manipulation approach was also capable of achieving droplet transport on a slope, multi-droplets transport, and multi-droplets synthesis.

Research and application of heat recovery and automation monitoring system for new energy vehicle motor equipment

In order to improve the energy efficiency of pure electric vehicles, the author proposes a thermal energy recovery and automation monitoring system for motor equipment based on new energy vehicles. Based on the analysis of the battery thermal management model, a series heat exchange model between the motor and the battery was established. An integrated thermal management system control strategy based on motor waste heat recovery was proposed for electric vehicles in low temperature environments, and simulation and validation were conducted at different environmental temperatures (-10~0 ?). The simulation results show that this configuration can shorten the heating time by 111-343 seconds compared to traditional battery thermal management systems during the heating stage. During the insulation stage, frequent activation of positive temperature coefficient thermistor can be avoided and the battery temperature can be maintained around 20?C, which is not only conducive to extending the battery life but also reduces the comprehensive energy consumption by 4.39-7.70%. On the other hand, this configuration can reduce the impact of low temperature on comprehensive energy consumption from 9.77-2.07%. It is proved that heat recovery can effectively alleviate the range anxiety caused by ambient temperature.

Cyclodextrin incorporated textile supercapacitor/piezo-triboelectric nanogenerator hybrid system for versatile temperature dependent wearable wireless devices

The problem of wearable textile electronics having no power source can be greatly assisted at low-temperature environments by the demand for flexible supercapacitor sustaining self-charging system. We explore a typical piezo-triboelectric nanogenerators (PTNGs) textile fabric integrated flexible supercapacitors (SCs) face substantial difficulty in maintaining their ability to quickly charge in colder environments for various wearable wireless sensing devices. PTNGs using composite electrodes frequently experience quick performance degradation at low energy levels as a result of the poor ion mobility besides charge transfer in the electrolyte. In this article, we offer a SC-coupled self-chargeable power generator with wide operating temperature range (25 ∼ −80 °C). A composite system of sulfonated β-cyclodextrin/polyvinylpyrrolidone/Ni@MnCO3 on cotton fabric with polyvinylidene fluoride and polydimethylsiloxane were used to build the smart textile SC, which produced 19.6 V at −80 °C and exhibited a gravimetric capacitance of 94.7 Fg−1 with excellent cyclic stability (>50,000). The biocompatibility studies reveal good results (∼95 % of cell viability) for the wearable textile SCs. In addition, the possibility of application to a sensing device was successfully demonstrated by connecting the proposed self-driving energy storage complex to a device designed as a wireless circuit. This system can work for seamlessly working for wireless signal transmittance as power source resulting and this system may be able to meet the urgent need for wearable electronics that implanted in the space suit and/or winter clothing needed in harsh climates.

Hydrogen-atom-assisted processes on thioacetamide in para-H2 matrix - formation of thiol tautomers.

TA has been isolated in low-temperature para-H2 matrices and it has been exposed to H atoms. In accordance with previous experimental results, TA exclusively exists in its more stable thione tautomeric form in the freshly deposited matrix. However, upon H atom generation, the bands belonging to the precursor start decreasing with the simultaneous appearance of new bands. By comparing the position of these new peaks with earlier results obtained in para-H2, they can be undoubtedly attributed to the presence of the higher-energy thiol tautomeric forms of TA. No other products could be observed, except for NH3. Quantum-chemical computations have been invoked to understand the mechanism behind the observed thione-thiol tautomerization assisted by H atoms. Accordingly, tautomerization starts with barrierless H-atom addition on the S atom of the thione resulting in the formation of the intermediate 1-amino-1-mercapto-ethyl radical (H3C-Ċ(-SH)-NH2), which has been detected tentatively for the first time. The second step is a barrierless H-atom induced H-abstraction from the -NH2 moiety of the H3C-Ċ(-SH)-NH2 radical. A comprehensive mechanism for tautomerization is proposed based on the experimental and theoretical results. Although earlier studies showed the possibility of TA thione-thiol tautomerization in cryogenic matrices achieved by energetic UV irradiation, the present study points out that this can also take place through a barrierless pathway by simply exposing the TA molecules to H atoms. As such, this is the first evidence for the occurrence of such a reaction in a matrix-isolated environment. The current results also help us better understand the mystery behind thione-thiol tautomerization in low-temperature environments.

Application of cold-adapted microbial agents in soil contaminate remediation: biodegradation mechanisms, case studies, and safety assessments.

The microbial agent technology has made significant progress in remediating nitro-aromatic compounds (NACs), such as p-nitrophenol, 2,4-dinitrophenol, and 2,4,6-Trinitrotoluene, in farmland soil over the past decade. However, there are still gaps in our understanding of the bioavailability and degradation mechanisms of these compounds in low-temperature environments. In this review, we provide a comprehensive summary of the strategies employed by cold-adapted microorganisms and elucidate the degradation pathways of NACs pollutants. To further analyze their metabolic mechanisms, we propose using mass balance to improve our understanding of biochemical processes and refine the degradation pathways through stoichiometry analysis. Additionally, we suggest employing 13C-metabolic flux analysis to track enzyme activity and intermediate products during bio-degradation processes with the aim of accelerating the remediation of nitro-aromatic compounds, particularly in cold regions. Through a comprehensive analysis of pollutant metabolic activities and a commitment to the 'One Health' approach, with an emphasis on selecting non-pathogenic strains, the environmental management strategies for soil remediation could be positioned to develop and implement safe and effective measure.

Low-temperature tensile properties of meta-stable β titanium Ti-5Al-5V-5Mo-3Cr alloy fabricated by pulsed laser powder bed fusion

Ti-5Al-5V-5Mo-3Cr (Ti-5553) alloy is increasingly used in structural airplane components, such as landing gear and fuselage, thanks to its high strength, good ductility, and low density. These components are consistently subjected to sub-zero temperatures during the flight. In this study, pulsed laser powder bed fusion (L-PBF) parameters were firstly optimized to fabricate highly dense (>99%) parts, and their effect on microstructure and microhardness was analyzed. Finally, tensile properties were evaluated under sub-zero temperature conditions and compared to the standard room ones to validate the feasibility of using Ti5553 under low-temperature environments.

Research on the Low-Temperature Stability of Anode and Electrolyte of Lithium-ion Battery

With the acceleration of technological progress, lithium-ion batteries (LIBs) have become one of the indispensable forms of energy in modern life and play a crucial role. However, its performance degradation in low-temperature environments remains a key factor restricting its further development. In particular, as the core components of LIBs, the stability of electrodes and electrolytes at low temperatures directly determines the overall performance of the battery. Specifically, the fluidity of the electrolyte is significantly reduced at low temperatures, while lithium-ions at the negative electrode are more easily precipitated, leading to the formation of lithium dendrites, which together affect the safety and life of the battery. This paper systematically analyses the latest advances in structure regulation and design of anode materials and electrolytes through an in-depth study of the low-temperature stability of LIBs. Modification methods for these key materials are described in detail, including strategies for optimising electrolyte additives and their positive effects on enhancing battery performance at low temperatures. In addition, the article discusses potential directions for future research in this area, aiming to provide guidance and reference for improving the performance of LIBs for applications in low-temperature environments.

Cryo-compression and annealing hardening of 7075 aluminum alloy

7075 aluminum alloy, as a lightweight, high-strength, and corrosion-resistant structural material, is widely used in the aviation industry. Because 7075 aluminum alloy is commonly used in structural components, its plastic processing ability is highly required by the usage environment. Recent studies have shown that 7075 aluminum alloy exhibits better deformation ability under low temperature conditions. In this paper Cryo-compression experiments on 7075 aluminum alloy under different compression rates (0.001 s-1-0.5 s-1) in a low-temperature environment (soaked in liquid nitrogen for 30 minutes) has been discussed. Annealing process research was conducted on the low-temperature compressed samples, and the optimal annealing process parameters (400Co, insulation for 15 minutes) and optimal deformation amount (16%) were obtained through comparison of microstructure and properties. And it was found that 7075 aluminum alloy exhibited annealing hardening phenomenon when annealed at 250 Co, and the reason was the diffusion segregation of solid solution elements formed during low-temperature forming, which led to the precipitation of the second phase MgZn2 during low-temperature annealing.

An ultra-stable Mn-based Prussian blue compound effectively suppresses Jahn–Teller distortion as a superior cathode material for sodium-ion batteries

By regulating the nucleation rate of the coprecipitation reaction, cubic NaMHCF was successfully prepared, which can effectively inhibit the Jahn–Teller effect and can work normally as the cathode of SIB even in low-temperature environments.

Study on the Compressive Properties of RPC Restrained by CFRP Sheet under Low-Temperature Curing

Abstract To address the problem of significant degradation of compressive properties of reactive powder concrete (RPC) after freezing during the curing period in a low-temperature environment, carbon fiber–reinforced polymer (CFRP) was used to restrain RPC specimens with carbon fiber filament content of 0 or 1 %, and axial compression tests were performed after low-temperature curing (20°C, −5°C, −15°C, and −25°C). The effects of temperature, restraint, and carbon fiber filament content on the compression properties of the RPC were analyzed. Results of the analysis showed that the mechanical properties of RPC under compression decreased with decreasing curing temperature. The use of CFRP sheets for the restraint of RPC specimens and the addition of carbon fiber filaments can both increase the ultimate load capacity of RPC specimens at each curing temperature, and the specimens were relatively intact after damage. With the addition of carbon fiber filaments, which can slow down the rate of decay of load capacity as curing temperature decreases, the degree of load capacity improvement is greater the lower the temperature. The degree of load capacity increase of the CFRP sheet decreases with decreasing temperature because of the weakening of the epoxy resin adhesive bond strength in the CFRP sheet at low temperatures. Both CFRP sheets and carbon fiber filament can increase the compressive pre-crack energy absorbed by RPC at each of the temperatures and can increase the toughness of RPC at low temperatures.

Strategies for electrolyte modification of lithium-ion batteries under low-temperature environments

Because of their high energy density, high voltage platform, extended cycle life, lack of memory effect, low self-discharge rate, environmental friendliness, and quick charging, lithium-ion batteries, or LIBs, are a vital component of contemporary electronic gadgets. Temperature has a complicated and wide-ranging effect on lithium-ion batteries, though. Lithium-ion batteries will have much-reduced performance, particularly in low-temperature conditions. The total performance of batteries is significantly impacted by the quality and performance of electrolytes in China. In particular, the electrolyte’s purpose in lithium-ion batteries is primarily to convey lithium ions; the battery’s ability to function at low temperatures is greatly influenced by the electrolyte’s ion conductivity and SEI film-forming capabilities. Thus, this article begins by providing an overview of the fundamental composition and properties of lithium-ion batteries. The impact of low-temperature circumstances on lithium ion performance was then discussed. Lastly, many modification techniques were suggested from the electrolyte’s point of view to enhance lithium-ion battery performance in low-temperature settings.

Research on the response of bitumen binder and bitumen mastic to physical hardening effect based on rheological properties

Bitumen materials will occur a physical hardening effect when stored isothermally in a low-temperature environment, and ignoring the physical hardening factor has become one of the important reasons for premature cracking of asphalt pavement during the service period. This paper investigates the response of bitumen binder and bitumen mastic to physical hardening effects at different storage temperatures and times using the bending beam rheometer and dynamic shear rheometer. The response of the material to physical hardening effects is analyzed through temperature index system changes, mathematical model fitting, and stiffness master curve fitting. Results indicate that the response of the material to physical hardening effects can be classified into two stages: the rapid growth and the gradual stabilization periods. The response time of these two stages is related to factors such as aging degree and storage temperature. The physical hardening effect will cause the temperature loss of the material at low temperature, and its influence law on TS60=300MPa and Tm60=0.300 is different. It is recommended to extend the isothermal storage time specified in the test from 1 h to 9 h, considering the time cost and the change in temperature index. Moreover, the stiffness master curve study revealed the occurrence of the "tail drift" phenomenon.

Additively Manufactured Flexible Electronics Filled with Ionic Liquid for Cryogenic Pressure Sensing

Flexible electronics have attracted increasing attention and are extensively used in medical care and health monitoring applications. However, research on their applications in low-temperature environments is limited, mainly owing to material intrinsic limitation. In this work, a cryogenic pressure sensor using low-melting (−71 °C) ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) is fabricated via the template removal method. The sensor unit can function at temperatures ranging from −50 to 30 °C, with improved sensing performance at lower temperatures. At −50 °C, it demonstrates an ultralow detection limit of 0.5 Pa and a high sensitivity of 2.0 × 10 5 Ω/kPa, thereby enabling the detection of dynamic pressure loads with different frequencies (0.2 to 2 Hz) and waveforms (sine and triangle). Subsequently, these units are integrated into a 3 × 3 array and embedded into a bionic thumb. The sensor can accurately identify up to 9 independent touch points and recognize dynamic sliding with velocities in the range of 0.31 to 4.42 cm/s at an extremely low temperature (−50 °C), thus demonstrating remarkable multitouch and sliding trajectory recognition capabilities. Furthermore, the proposed sensor unit is expected to contribute to the research on the human–machine interface of space suits.

Exploring the chemical dynamics of phenanthrene (C14H10) formation via the bimolecular gas-phase reaction of the phenylethynyl radical (C6H5CC) with benzene (C6H6).

The exploration of the fundamental formation mechanisms of polycyclic aromatic hydrocarbons (PAHs) is crucial for the understanding of molecular mass growth processes leading to two- and three-dimensional carbonaceous nanostructures (nanosheets, graphenes, nanotubes, buckyballs) in extraterrestrial environments (circumstellar envelopes, planetary nebulae, molecular clouds) and combustion systems. While key studies have been conducted exploiting traditional, high-temperature mechanisms such as the hydrogen abstraction-acetylene addition (HACA) and phenyl addition-dehydrocyclization (PAC) pathways, the complexity of extreme environments highlights the necessity of investigating chemically diverse mass growth reaction mechanisms leading to PAHs. Employing the crossed molecular beams technique coupled with electronic structure calculations, we report on the gas-phase synthesis of phenanthrene (C14H10)-a three-ring, 14π benzenoid PAH-via a phenylethynyl addition-cyclization-aromatization mechanism, featuring bimolecular reactions of the phenylethynyl radical (C6H5CC, X2A1) with benzene (C6H6) under single collision conditions. The dynamics involve a phenylethynyl radical addition to benzene without entrance barrier leading eventually to phenanthrene via indirect scattering dynamics through C14H11 intermediates. The barrierless nature of reaction allows rapid access to phenanthrene in low-temperature environments such as cold molecular clouds which can reach temperatures as low as 10 K. This mechanism constitutes a unique, low-temperature framework for the formation of PAHs as building blocks in molecular mass growth processes to carbonaceous nanostructures in extraterrestrial environments thus affording critical insight into the low-temperature hydrocarbon chemistry in our universe.

VIBRATION ANALYSIS OF HEAVY WEAPONS IN TRANSIT BY AIRCRAFT IN FRACTAL SPACE CONSIDERING LOCATION DEVIATION

Air transportation constitutes a significant advancement in enhancing transportation efficiency. Nonetheless, when this modality is employed for the transit of large-scale armaments and equipment, the vibrational properties of these items within the aircraft’s cabin, coupled with potential deviations from their designated installation positions, emerge as critical factors that could compromise the safety of such transportation endeavors. To accommodate the unique environmental conditions of low-temperature and low-pressure prevalent in high-altitude air transportation, this model employs a fractal frequency formula for an expedited and accurate characterization of vibrational properties, while also providing a detailed analysis of the errors attributable to positional deviations in these vibration assessments. The findings of this research demonstrate that the computational accuracy achieved herein surpasses that of the variational iteration method (VIM) and the homotopy perturbation method (HPM). Moreover, the investigation into the damping effects of inertial forces within fractal dimensions unveils innovative prospects for optimizing nonlinear vibration systems under the challenging conditions of low-temperature and low-pressure environments.

Diatoms in a sediment core of Lake Raifskoye (Volzhsko-Kamsky Nature Reserve, Republic of Tatarstan): lake development over the past 1200 years

Studies of the diatom assembly in a 130-cm sediment core from Lake Raifskoye reveal 79 taxa of diatoms ranking below the genus of two classes (centric - 14, pennate - 65). 14C, 210Pb and 137Cs dating results show that the sediment core covers a continuous deposition since 1200 cal. yr BP. During the development of the lake, three periods were identified. In the range of 600-1200 years ago unfavourable conditions for the development of diatoms were noted, presumably due to low environmental temperatures. Period from 150-450 years ago reflects good conditions for the development of diatoms and, as a consequence, an increase in the productivity of algal communities in the lake against the backdrop of rising air temperatures. In the third, modern period, the processes of increasing the productivity of algal communities continue, which can also be associated with an increase in air temperature.

Study and simulation of cryogenic bi-periodic accelerating structure with TM02 mode

To further enhance the accelerating gradient of accelerators, we designed a cryogenic C-band standing wave bi-periodic accelerating structure for the Shanghai Soft X-ray Free Electron Laser Facility (SXFEL). According to the low-temperature environment, material characteristics and technological conditions, the design is completed and it is decided to design the accelerating structure into a bi-periodic magnetic coupling structure. It is a 17-cell structure consisting of 9 accelerating cavities and 8 coupling cavities. To guarantee the symmetry of the field, the structure is doubly-fed. Operating with the π/2 mode standing wave, it is much less sensitive than the standing-wave structure of π-mode. Additionally, the microwave mode is TM02 in coupling cavities that are larger and even less sensitive than the traditional bi-periodic structure. The shape of the coupling cavity can be redesigned to make it tunable.

Evaluation of Compressive Strength of UHPC Cured in A Winter Low-temperature

Deteriorating concrete quality is a typical problem reported in a low-temperature environment in winter. Therefore, efforts to evaluate and secure the quality of concrete are always carried out. In this study, the researchers primarily focused on developing curing methods and improving the quality of mixing materials, including chemical admixture, to secure compressive strength of concrete. The study investigated the compressive strength of concrete according to its age and observed that the compressive strength increases under the experimental conditions without any additional protection measures for the winter season. The compressive strength of the cured concrete was measured at 0 and -15 ℃ for 100 MPa Ultra-high-performance concrete (UHPC). Additionally, the property of compressive strength was compared with that of UHPC, which suffered damage due to the cold, went through a certain recovery period at room temperature. Consequently, it was confirmed that UHPC, damaged from the cold weather, achieved the specific compressive strength after 84 days. The findings from this study can enhance further understanding of the characteristics of UHPC in winter environments and contribute to establishing a construction plan for withstanding the winter seasons.

Effects of extreme high and low environmental temperature in Bangladesh perspective on clinical parameters in goats

In this study, Black Bengal (BB) goats' physiological characteristics were examined in relation to high and low ambient temperatures. The investigation was carried out throughout the winter months (November- February) and the summer months (April- July). Twelve experimental Black Bengal goats of either sex was used in this experiment and were aged between 2-3 years old with a body weight of 18 to 23 kg. A digital hygrometer and thermometer installed in the animal shed were used to record the daily temperature in the surrounding air and relative humidity to compute the temperature-humidity index (THI). Physiological parameters (respiratory rate, heart rate and rectal temperature) of the animals were noted daily during the experimental period. According to this study, all of the animals endured extremely high levels of heat and cold stress in the summer and winter, with the temperature humidity index (THI) recorded in the summer was 30.5 ± 0.51 and the winter was 16.37 ± 1.51. Throughout the summer and winter, all BB goats showed significant alterations in their clinical parameters. The results of the study indicated that seasonal and recording-time differences in rectal temperature, heart rate, and respiration rate were statistically (P<0.05) substantial. It has been found that THI in Black Bengal goats is more influenced by ambient temperature than relative humidity and is a sensitive indication of both heat and cold stress. Therefore, heat stress is associated with certain physiological effects in Black Bengal goats.

Crude Oil Degradation in Temperatures Below the Freezing Point by Bacteria from Hydrocarbon-Contaminated Arctic Soils and the Genome Analysis of Sphingomonas sp. AR_OL41.

Intensive human activity in the Arctic region leads to hydrocarbon pollution of reservoirs and soils. Isolation of bacteria capable of growing at low temperatures and degrading oil and petroleum products is of scientific and practical value. The aim of this work was to study the physiology and growth in oil at temperatures below 0 °C of four strains of bacteria of the genera Pseudomonas, Rhodococcus, Arthrobacter, and Sphingomonas-previously isolated from diesel-contaminated soils of the Franz Josef Land archipelago-as well as genomic analysis of the Sphingomonas sp. AR_OL41 strain. The studied strains grew on hydrocarbons at temperatures from -1.5 °C to 35 °C in the presence of 0-8% NaCl (w/v). Growth at a negative temperature was accompanied by visual changes in the size of cells as well as a narrowing of the spectrum of utilized n-alkanes. The studied strains were psychrotolerant, degraded natural biopolymers (xylan, chitin) and n-alkanes of petroleum, and converted phosphates into a soluble form. The ability to degrade n-alkanes is rare in members of the genus Sphingomonas. To understand how the Sphingomonas sp. AR_OL41 strain has adapted to a cold, diesel-contaminated environment, its genome was sequenced and analyzed. The Illumina HiSeq 2500 platform was used for AR_OL41 genome strain sequencing. The genome analysis of the AR_OL41 strain showed the presence of genes encoding enzymes of n-alkane oxidation, pyruvate metabolism, desaturation of membrane lipids, and the formation of exopolysaccharides, confirming the adaptation of the strain to hydrocarbon pollution and low habitat temperature. Average nucleotide identity and digital DNA-DNA hybridization values for genomes of the AR_OL41 strain with that of the phylogenetically relative Sphingomonas alpine DSM 22537T strain were 81.9% and 20.9%, respectively, which allows the AR_OL41 strain to be assigned to a new species of the genus Sphingomonas. Phenomenological observations and genomic analysis indicate the possible participation of the studied strains in the self-purification of Arctic soils from hydrocarbons and their potential for biotechnological application in bioremediation of low-temperature environments.