Characteristics Of Low Temperature Research Articles

Microbial and hydrothermal dolomite formation in Early Cretaceous lacustrine sediments in Yin'e Basin: Insights from petrology and geochemistry

Dolomite is widely present in geological history, but its origin has always been a prominent problem that troubles sedimentologists. For lacustrine dolomite, current research has not yet provided a reliable explanation for its complex genesis mechanism. The Early Cretaceous lakes in Northwest China host various morphological dolomites, providing valuable materials for exploring the origin of dolomites. According to their petrological and mineralogical characteristics, it can be divided into thick laminated dolomite, thin laminated dolomite, dolomitic mudstone, and vein dolomite. The ratios of trace elements and rare earth elements show that these dolomites precipitated in a brackish–suboxic environment. The high δ13C values (>8 ‰VPDB) of thick laminated dolomite and some thin laminated dolomite suggest the involvement of methane-producing microorganisms in the precipitation of dolomite, and the appearance of microscale/nanoscale spherical dolomite aggregates and the dispersed organic matter around dolomite particles jointly confirm that microbial-mediated biological activity promotes dolomite precipitation. The dolomite stoichiometry (mole % MgCO3) confirms that thick laminated dolomite was deposited in a restricted shallow water environment, while dolomitic mudstone is mainly deposited in relatively open water areas. The thin laminated dolomite in the shale laminae represents short-term or seasonal climatic and environmental fluctuations. In addition, some carbonate minerals of dolomitic mudstone in shallow water environment recrystallized by post-depositional hydrothermal effect, resulting in δ18O value decreased (<−10 ‰VPDB). The vein dolomite is characterized by high rare earth content and low δ13C and δ18O values, and its Sr isotope (0.712894 ± 0.000374) values reflect that the hydrothermal fluid may have been formed by the mixing of infiltrating lake water and crustal magmatic water. According to the characteristics of fluid inclusions, it is inferred that the hydrothermal fluid has the characteristics of low temperature (108.3 °C–159.8 °C), medium salinity (3.5 wt%–14.3 wt% NaCl) and high density (0.95–1.00 g/cm3). The microbial mediation and tectonic hydrothermal fluids play an important role in the formation of the Early Cretaceous lacustrine dolomite.

Preparation and microstructure of Cu-Al2O3 composites by a novel supercritical water liquid phase in-situ reaction method

The high solubility, reactivity and solubility of supercritical water provide a new way for the preparation of advanced metal matrix composites. In this paper, Cu-Al2O3 composites are prepared by supercritical water liquid phase in situ reaction (SW-LIR). In this method, the Cu-Al atomized alloy powder are used as raw material, deionized water as reaction medium, H2O2 as liquid phase oxygen source, and the Cu-Al2O3 composite powder are prepared at 380 ℃ and 22.1 MPa for 10 min. The Cu-Al2O3 composite block is prepared by spark plasma sintering (SPS). The results show that Al2O3 has an average size of 41.8 nm and mainly exists in the form of mixed crystals. The interface with the matrix is coherent or semi-coherent. With the increase of Al2O3 content, the mechanical properties of the composites are obviously improved. When the Al2O3 content is 1.12 wt%, the microhardness is as high as 164.52 HV and the tensile strength is 441 MPA, while still maintaining a high electrical conductivity (75 %IACS). At the same time, it shows quite excellent high temperature performance. It can still retain the characteristics of high strength at 1000℃, which solves the shortcomings of high thermal conductivity but low strength of pure copper. Compared with the traditional method, SW-LIR method has the characteristics of low reaction temperature, fast reaction speed and green environmental protection.

Optimization and performance improvement of ultra-low temperature cascade refrigeration system based on the isentropic efficiency curve of single-screw compressor

In this paper, a cascade refrigeration system equipped with a single-screw compressor (SSC-CRS) is proposed and built in order to achieve the goal of high load cooling capacity under ultra-low temperature conditions. Firstly, the isentropic efficiency curve of the single-screw compressor (SSC) is fitted through experimental method in response to the characteristics of low suction temperature and large pressure ratio of the compressor. In addition, the analysis of SSC-CRS with 28 refrigerant pairs are made to compare the coefficient of refrigeration (COP) and power consumption. On the basis of the cascade system, the paper compares the improvement of performance between two circuits with SSC: vapor injection cascade refrigeration system (SSC-ICRS) and ejector vapor injection cascade refrigeration system (SSC-EICRS). The results indicate the COP improvement rate of SSC-ICRS system is 17.39 %–41.98 % and the COP improvement rate of SSC-EICRS system is 49.46 %–68.37 % compared with SSC-CRS.

Feasibility study on titanium‐catalyzed polyester for the preparation of high‐strength industrial yarns

AbstractIn order to overcome the environmental pollution or personal injury caused by precipitation of heavy metal ions during post‐processing and application of antimony‐catalyzed polyester industrial yarns, the titanium catalyst was used to prepare polyethylene terephthalate (PET) with high molecular weight, and then the titanium‐ catalyzed PET properties related to spinning kinetics were investigated as a basis for designing the drying, melting, spinning and extrusion, cooling, hot stretching and heat‐ setting process parameters. Compared with the spinning process of antimony‐catalyzed polyester of similar molecular weight, based on the lower melting point and melt viscosity of titanium‐catalyzed PET, the spinning temperature was lowered by about 5°C to reduce the thermal degradation of PET during extrusion, and the hot stretching speed and temperature were appropriately lowered based on the characteristics of low crystallization temperature and high crystallization rate in the heating process so that a product with a breaking strength of 8.29 cN/dtex was developed on an industrial device successfully. Titanium‐catalyzed high‐strength polyester industrial yarns, the structure and properties of crystal orientation, lamellar thickness, strength and elongation at break were comparable with those of antimony‐catalyzed polyester industrial yarns.

Research progress of ultracold ion source

&lt;sec&gt;Nanobeam is an advanced technology for preparing charged ion beams with spot diameters on a nanometer scale, and mainly used for high-resolution and high-precision ion beam analysis, ion beam fabrication and ion beam material modification research. The nanobeam devices play an important role in realizing material analysis, micro/nano fabrication, microelectronic device manufacturing and quantum computing. The high-quality ion source is one of the key components of nanobeam device, the performance of which directly affects the resolution and precision of the nanobeam system. However, the traditional ion source used in this system is limited to available ionic species, large energy spread and complex structure. These issues hinder their ability to meet emerging application scenarios that require multi-ion types and high resolution. This emphasizes the importance of creating newion sources as soon as possible.&lt;/sec&gt;&lt;sec&gt;With the development of laser cooling technology, ultracold ions with temperatures in the range of mK or even μK can be obtained based on photoionization of cold atoms and laser cooling of ions. The typical characteristics of low temperature and easy operation greatly promote the emergence of ultracold ion sources. The ultracold ions exhibit extremely small transverse velocity divergence, which can significantly enhance the brightness and emittance quality parameters of the ion source, bringing great opportunities for innovating nano-ion beam technology. Therefore, the research on ultracold ion sources is of great significance for achieving high-quality ion sources with higher brightness, smaller size, lower energy dispersion, more diverse ion species, and simplified structure. Here, we introduce the important achievements in basic research and application technology development of magneto-optical trap ion sources, cold atomic beam ion sources, and ultracold single ion sources from the aspects of preparation principles, generation methods, and typical applications, and review the recent research progress of ultracold ion sources. Finally, we provide an outlook on the future development and application prospects of ultracold ion sources.&lt;/sec&gt;

Application of artificial hibernation technology in acute brain injury.

Controlling intracranial pressure, nerve cell regeneration, and microenvironment regulation are the key issues in reducing mortality and disability in acute brain injury. There is currently a lack of effective treatment methods. Hibernation has the characteristics of low temperature, low metabolism, and hibernation rhythm, as well as protective effects on the nervous, cardiovascular, and motor systems. Artificial hibernation technology is a new technology that can effectively treat acute brain injury by altering the body's metabolism, lowering the body's core temperature, and allowing the body to enter a state similar to hibernation. This review introduces artificial hibernation technology, including mild hypothermia treatment technology, central nervous system regulation technology, and artificial hibernation-inducer technology. Upon summarizing the relevant research on artificial hibernation technology in acute brain injury, the research results show that artificial hibernation technology has neuroprotective, anti-inflammatory, and oxidative stress-resistance effects, indicating that it has therapeutic significance in acute brain injury. Furthermore, artificial hibernation technology can alleviate the damage of ischemic stroke, traumatic brain injury, cerebral hemorrhage, cerebral infarction, and other diseases, providing new strategies for treating acute brain injury. However, artificial hibernation technology is currently in its infancy and has some complications, such as electrolyte imbalance and coagulation disorders, which limit its use. Further research is needed for its clinical application.

Thermal and fatigue endurance strain response in low temperature sintered 0.4PZN-0.6PZT ceramics for actuator applications

Piezo-ceramics with low sintering temperature (<1000 °C), enhanced strain (>0.1 %), low degree of hysteresis (<10 %), fatigue resistance (>106 cycles) with better thermal stability are extremely important characteristics for the development of high performance and cost-effective actuators. In this study, temperature (−50 to 250 °C) and fatigue (100 to 106) dependence of ferro/piezoelectric (P-E/S-E) characteristics of low temperature sintered (950 °C) (0.4[Pb(Zn1/3Nb2/3)O3-0.6Pb(Zr0.49Ti0.51)O3]) ceramics was investigated. A thermally stable strain response with a maximum of 0.17 % and degree of strain hysteresis (ηhys) of < 10 % was observed till 250 °C. The fatigue studies revealed a robust unipolar strain stability till 106 cycles even up to 200 °C. Interestingly, a very minimal strain asymmetry (γS) was observed only after 104 cycles till 200 °C, unlike PZT-5A, PIC151 and PMN-PT. This study demonstrates an exceptional thermal and fatigue resistant strain response even close to the Curie transition temperature (TC ∼ 280 °C) and suggests that the low temperature sintered 0.4PZN-0.6PZT ceramics could be a promising material, exclusively for high-precision actuator applications over a wide temperature range with a cost-effective solution.

Upward migration of calanoid copepods is driven by high food quality in surface waters in an alpine lake

Abstract The diel vertical migration of zooplankton includes downward migration to deep water during the day and upward migration to surface water at night. Diurnal downward migration has been well explained; zooplankton migration to surface water at night remains unclear. This study aimed to explore the reason of the nocturnal upward migration of the calanoid copepod Arctodiaptomus sp. In Lake Heihai, an alpine lake (elevation 4,090 m above sea level) without predators. Herein, we present the vertical profiles of the lake, including water temperature, chlorophyll a (Chl‐a), fatty acids, and astaxanthin synthesis precursors (ASPs) of seston in the water column. The distributions and concentrations of fatty acids and astaxanthin in Arctodiaptomus sp. were characterised through field investigations during the day and at night. Meanwhile, the effect of ultraviolet radiation (UVR) on ASPs in seston was explored through indoor experiments. Lake Heihai had the characteristics of low temperature, low food availability, high transparency, and high UVR intensity. Arctodiaptomus sp. was distributed in water layers below 6 m during the day and throughout the water column at night. Arctodiaptomus sp. accumulated large amounts of fatty acids, especially polyunsaturated fatty acids (PUFAs), and inhibitors of fatty acid oxidation–astaxanthin in the cold alpine lake. The concentrations of lutein, a kind of ASP, and PUFAs in seston were highest in surface waters. The indoor experiment verified that UVR can enhance the synthesis of ASP. The calanoids migrated to surface waters at night to obtain ASPs and PUFAs in seston, which were at high concentrations in surface waters. PUFAs and ASP may be of high food quality for zooplankton in alpine lakes. The findings indicated that the upward migration of Arctodiaptomus sp. at night was driven by the high quality of food sources (PUFAs and ASP) in surface waters. Arctodiaptomus sp. adapts behaviour and physiology to the environment of the alpine lake. We explored why zooplankton migrated to surface waters at night from the perspective of their physiological characteristics and adaptability to the environment. Our findings provide a new way to investigate the diel vertical migration of zooplankton, especially in alpine lakes.

The genesis of acid alteration in the Luohe IOA-type deposit, Eastern China and its constraints on mineralization

Luohe is the largest IOA-type deposit in the Middle and Lower reaches of the Yangtze Metallogenic belt. The iron ore body is hosted in thick volcanic rocks, and widespread acidic alteration (secondary quartzite) developed at shallow depths, providing an excellent opportunity to study the genesis of acidic alteration rocks and the genetic links with the IOA mineralization. In this study, detailed mineralogy, in situ sulfur isotopes, and trace element analyses were performed on pyrite from a shallow drill hole in the Luohe deposit. The results indicate that the formation time of acidic alteration is between magnetite (stage II) and anhydrite-pyrite (stage IV), with pyrite sulfur isotopes ranging from −14 to 4‰, which is significantly different from those in stage IV (7-9‰). The anomaly negative sulfur isotope suggests the existence of SO2 disproportionation reaction, and the δ34S of pyrite increases with depth decrease, ultimately falling within the mantle sulfur range. This indicates that the sulfur origin of acidic alteration pyrite is a single magma sulfur source, which is significantly different from the deep iron mineralization system (magmatic + evaporite). The trace elements Co, Ni, As, Ti, Cu, Sb, Tl in pyrite indicate that the acidic alteration fluid has the characteristics of low temperature, low pH, and is rich in F and Cl. Combined with the sulfur isotope results, it is believed that pyrite in the acidic alteration rock of the Luohe was formed by the mixing of gaseous SO2 and shallow groundwater, which is a part of the Luohe magmatic-hydrothermal mineralization system and an important indication for regional exploration of similar deposits.

Research of numerical simulation for HVAF thermal spraying process on rotational roll

AbstractHVAF thermal spraying has the characteristics of low spraying temperature, high coating density, and strong corrosion resistance. It is widely used in the aerospace, iron–steel metallurgy, national defense and military industry, petrochemical industry, and other fields for manufacturing protection and repair strengthening, which has achieved significant economic benefits. In this study, a numerical model of HVAF thermal spraying on a circular roll was established by the computational fluid dynamics method. The characteristics of the spraying flame, evolution of the gas composition mass fraction, and influence of the spraying parameters on particle flight behaviors were calculated and revealed. Based on the dynamic mesh method, the effect of roll speed on the spraying flame characteristics and particle flight behaviors was analyzed. Calculations show that the spraying flame is extruded at the Laval nozzle and the speed rapidly increases to 805 m/s, which increases to a supersonic speed through the barrel. The flame flow rises rapidly reaching the surface of the roll, which is 780 m/s. The highest temperature is in the combustion chamber, and the flame temperature of the airshed is a damped vibration. The flame covers the surface of the roll to preheat it, and the flame temperature there decreases layer by layer from the inside to outside. The particle diameter significantly effects the powder flight behavior. The flame velocity increases with the barrel length increasing. The flame temperature up to the peak when the barrel length is 190 mm. As the rotation speed of the roll increases, the temperature, velocity, and pressure of the flame flow on the roll surface change in a certain extent. The particle spatter will be increased with the rotational speed increasing of the roll, which little affects the particle temperature.

Characteristics of drought, low temperature, and concurrent events of maize in Songliao Plain

AbstractMaize is susceptible to drought and low temperatures. In recent years, drought, low temperatures, and their composite events have often occurred during the growth period of maize, causing a huge impact. In this study, maize in the Songliao Plain was used as the research object. Based on the crop water surplus deficit index (CWSDI) and heat index (F(T)), combined with the Theil–Sen median and Mann–Kendall tests (Sen–MK) and empirical orthogonal function (EOF), the temporal trends and spatial patterns of drought and low temperatures in different growth periods of maize were obtained. Copula modelling was used to analyse the joint probability distribution and return period of drought and low temperatures. The results showed that the temporal variation trend of the CWSDI was significantly different at different growth periods of maize, and there were different trends and spatial modal distributions. However, the temporal variation trend of F(T) was similar, showing a downward trend over the entire region. There was no obvious asymmetry or skew‐dependent structure in the distribution of concurrent events of drought and low temperature; however, the joint probability contours of different growth periods were biased to the upper left. The recurrence period of drought and low‐temperature concurrent events was within 2 years, and the recurrence period was basically between 2 and 5 years, with a reduction in drought or low temperatures.

A new method of parameter identification for proton exchange membrane fuel cell based on hybrid particle swarm optimization with differential evolution algorithm

With the characteristics of high energy conversion efficiency, high energy den?sity and low operating temperature, the proton exchange membrane fuel cells (PEMFC) have become one of the green energy sources with broad prospects. The establishment of accurate mathematical model of the PEMFC is the basis of simulation and control strategy. At present, some intelligent algorithms have certain drawbacks, and can hardly find the balanced point between precision and computational time. In this study, a novel parameter identification approach com?bining the hybrid particle swarm optimization (PSO) algorithm with differential evolution, i.e. hybrid DEPSO, is proposed to obtain the unknown parameters in the PEMFC mathematical model and solve the problems of premature convergence of PSO and poor global search ability of differential evolution. Six benchmark functions are applied to verify the performance of the algorithm. The results prove that the hybrid DEPSO can evade local optimum preferably while having swifter convergence rate. Two PEMFC stacks are investigated and modeled. In order to evaluate the accuracy of model, the sum of squared errors between the measured voltage and the estimated output voltage are examined. Numerical results show higher accuracy of the hybrid DEPSO-based model comparing with other recently published optimization approaches. Furthermore, the simulation results indicate that the accuracy of the PEMFC model optimized by the hybrid DEPSO algorithm improves 0.19-1.86%, which can provide a new solution the multi-objective opti?mization problem and promote the practical application of the PEMFC.

Research Progress of Tung Oil/UV Photocomposite Curing Material

Tung oil (TO)/ultraviolet (UV) photo-composite curing material possesses the characteristics of low curing temperature, low material shrinkage and low environmental pollution. Accordingly, this material must be developed and utilized with the conjugated double bonds contained in the long chain of the main structure (α-tung acid) molecules in the refined TO. The aforementioned material can be chemically modified using a variety of chemical methods to develop a new TO-based UV photocurable material due to its unique chemical properties. This work reviews the research progress of TO/UV photo-composite curing materials in recent years. Firstly, the chemical structure and application of TO and UV Photocatalysis Technology were briefly introduced. Secondly, the research status of novel TO/UV photo-composite curing materials developed by the Diels-Alder reaction was discussed. The method and curing effect of the UV curing system constructed by other chemically modified TO were also discussed. Thereafter, the application of TO in industrial production is introduced from four directions: the application of TO in biodiesel, the application in synthetic resin, the application in self-healing coating and microcapsules and other applications. Finally, the research and application prospects of TO/UV photo-composite curing materials were presented.

Intelligent Control Method for Head Thickness of Plate

In the process of plate rolling, the characteristics of low head and tail temperature, large biting impact, and large torsional vibration affect the high-precision control of thickness, which makes it difficult to further improve the control accuracy of the traditional GM-AGC model based on feedback control. Using the characteristics of reversible plate rolling, the processing history information of the rolled piece during the entire rolling process is tracked, and the known information of the previous pass is used to intelligently correct the subsequent pass. Based on the traditional absolute AGC control model, adaptive thickness feedforward control is carried out for the sharply changing position of the thickness at the head of the rolling piece to reduce the thickness deviation of the unstable position.

Crescent-Shaped Low-Temperature Distribution along the Convex Topography in the Southeastern Edge of Taiwan Bank in Summer

Abstract Various physical mechanisms of ocean upwelling usually occur near or along coastal regions worldwide. Five upwelling zones of unequal intensity are found around the Taiwan Strait, and the Taiwan Bank (TB) upwelling zone has the most prominent characteristics of low temperature. In this study, satellite images, shipboard ADCPs (acoustic Doppler current profilers), and CTDs (conductivity–temperature–depth measures) were analyzed to investigate the processes of cold water upwelling around the TB shoaling zone. In addition, the MITgcm numerical model and the flexible cubic spline technique were also employed, allowing us to better understand those processes. The model results suggested that a combination of Ekman transport and the centrifugal force, driven by the geostrophic South China Sea Warm Current (SCSWC), constitutes a physical mechanism to contribute the vigorous upwelling in the TB shoal zone. The upwelling is largely driven by Ekman transport. However, the centrifugal force may explain why the upwelling with a crescent-shaped distribution of low temperatures along the convex topography of the southeastern edge of the TB shoaling zone is more prominent than expected, as it tends toward the so-called gradient wind balance. Sudden relaxation of the friction force occurred because of the very sharp shelf break (20–60 m) and steep slope topography; a discontinuous velocity zone around the shelf break could also lead to vigorous cold water upwelling. Significance Statement Extensive data concerning the Taiwan Bank (TB) shoaling zone have been collected in the past decade in an attempt to improve understanding of the process of cold water upwelling in the area. Because the Kuroshio invades the South China Sea from the east, and the South China Sea Warm Current flows northeastward around the southeastern edge of the TB, water circulation in and around the sandbar is very complicated. Thus, we expanded our model range from small to large scale to avoid the open boundary settings of small-scale model (including the temperature and salinity fields, wind stress, and the model driving forces), which were not easy to set up. Thus, we used a large-scale, high-resolution circulation model to study a small-scale ocean region. Physical processes of this upwelling can finally be verified in the small-scale region. To compensate for the insufficient resolution of the large-scale numerical model, our strategy was to utilize the flexible cubic spline technique to resolve the curvature of the markedly meandering currents. In light of scale analysis, the results showed that in addition to the critical contribution of Ekman transport to the upwelling, the effects of centrifugal forces on upwelling in the TB shoal zone need to be considered.

Analysis and Experimental Research on Efficiency Characteristics of a Deep-Sea Hydraulic Power Source

The deep-sea environment has the characteristics of high pressure and low temperature. In addition to the extremely high requirements on the structural reliability, the ultra-high ambient pressure also has a great impact on the working characteristics of the hydraulic source. In this paper, the efficiency characteristics of a deep-sea hydraulic source are studied in the full-ocean-depth pressure range. According to the power transfer process, the efficiency of the deep-sea motor, gear pump and hydraulic circuit is analyzed. In so doing, the oil friction loss of the motor rotor, the internal leakage of the gear pump, the viscous friction loss of the hydraulic system, etc., are calculated. Then, simulating the deep-sea high-pressure environment by the pressure cylinder, the output characteristics and corresponding input power of the prototype are measured. By analyzing the experimental data, the efficiency characteristic curve of the hydraulic source prototype, changing with the ambient pressure, is obtained. The experimental and calculation results show that, with the increase of ambient pressure, the system efficiency of the hydraulic source prototype increases first and then decreases.

Sedimentary Environments of Cambrian–Ordovician Source Rocks and Ultra‐deep Petroleum Accumulation in the Tarim Basin

AbstractThe Tarim Basin is the only petroliferous basin enriched with marine oil and gas in China. It is presently also the deepest basin for petroleum exploration and development in the world. There are two main sets of marine Source Rocks (SRs) in the Tarim Basin, namely the high over‐mature Cambrian–Lower Ordovician (∊ –O1) and the moderately mature Middle–Upper Ordovician (O2–3). The characteristic biomarkers of SRs and oils indicate that the main origin of the marine petroleum is a mixed source of ∊ –O1 and O2–3 SRs. With increasing burial, the hydrocarbon contribution of the ∊ –O1 SRs gradually increases. Accompanied by the superposition of multi‐stage hydrocarbon‐generation of the SRs and various secondary alteration processes, the emergence and abnormal enrichment of terpenoids, thiophene and trimethylaryl isoprenoid in deep reservoirs indicate a complex genesis of various deep oils and gases. Through the analysis of the biofacies and sedimentary environments of the ∊ –O1 and O2–3 SRs, it is shown that the lower Paleozoic high‐quality SRs in the Tarim Basin were mainly deposited in a passive continental margin and the gentle slope of the platform, deep‐water shelf and slope facies, which has exhibited a good response to the local tectonic‐sedimentary environment. The slope of the paleo‐uplift is the mutual area for the development of carbonate reservoirs and the deposition of marine SRs, which would be favorable for the accumulation of petroleum. Due to the characteristics of low ground temperature, the latest rapid and deep burial does not cause massive oil‐cracking in the paleo‐uplift and slope area. Therefore, it is speculated that the marine reservoirs in the slope of the Tabei Uplift are likely to be a favorable area for deep petroleum exploration, while the oil‐cracking gas would be a potential reserve around the west margin of the Manjiaer Depression. Hydrocarbons were generated from various unit SRs, mainly migrating along the lateral unconformities or reservoirs and the vertical faults. They eventually brought up three major types of exploration fields: middle and lower Cambrian salt‐related assemblages, dolomite inner reservoirs and Middle and Lower Ordovician oil‐bearing karst, which would become the most favorable target of marine ultra‐deep exploration in the Tarim Basin.

Impact of Regional Climate Change on the Development of Lithium Resources in Zabuye Salt Lake, Tibet

Climate change has important implication for the ecological environment and human social activities. The Qinghai-Tibet Plateau is a sensitive area for climate change, and the lakes on the Qinghai-Tibet Plateau are known as the “guardians” of climate change. However, there are few studies on the impact of climate variations on the exploitation of lithium resources in salt lakes. In this work, the collected data from Zabuye Salt Lake Observation Station and the experimental data of brine at different temperatures were employed as the research objects to investigate the relationship between regional climate change and lithium resources in salt lakes. The results indicated that Zabuye Salt Lake had abundant solar energy resources from 1991 to 2020 with the annual average sunshine duration of 3,122.4 h, the average annual evaporation of 2,579.07 mm/yr, and the annual average precipitation of 168.65 mm/yr. The average annual evaporation is around 15.3 times the average annual precipitation, owing to the short rainy season and the low rainfall. The phase diagram displayed that two lithium carbonate precipitation peaks clearly appeared at 25°C, and no obvious precipitation peak appeared at 15°C, indicating that a high-grade lithium carbonate mixed salt was prone to be formed at a higher temperature while lithium ions was more inclined to enrich in brine at a lower temperature. Therefore, Zabuye Salt Lake with the characteristics of low temperature, large temperature difference, less precipitation, strong radiation and large evaporation could be applied as unique lithium resources in the salt gradient solar pond, which would play a positive role in the development of salt lake resources.

Thermodynamic exploration of two-stage vacuum-pressure swing adsorption for carbon dioxide capture

Adsorption technology is recognised as a promising CO2 capture method due to its characteristics of low regeneration temperature. Analysis model based on carbon pump concept could be used to reveal thermal performance of various carbon capture technologies. However, the concept still has a large gap to become a comprehensive theory. This paper aims to evaluate thermodynamic performance of two-stage vacuum-pressure swing adsorption (VPSA) from a new definition of single-stage VPSA cycle. Energy consumption and exergy efficiency of VPSA cycles are evaluated and compared. Results indicate that introduction of the second stage can significantly elevate the concentration of product gas with less energy input increase. Also, energy consumption decreases from 114.53 kJ mol−1 to 28.23 kJ mol−1 when initial concentration of CO2 rises from 15% to 75%. However, there is a maximum value of exergy efficiency, 7.01% when initial concentration is 45%. Non-discharged CO2 molecules remained in the void of bed after evacuation process will significantly influence the concentration of product gas. The final concentration of product gas achieves the minimum of 91.90% when concentration differences are both 10% at two stages. One remarkable fact is that a new definition of VPSA cycle may be more feasible for thermal analysis in real applications.

Effects of different colorants on service performance for colored asphalt pavement in cold regions

PurposeThe service performance for colored asphalt pavement is inevitably affected by the addition of different colorants, especially the challenge of low temperature environment in cold regions. Therefore, the purpose of study is to explore the effects of different colorants on the service performance for colored asphalt pavement and to provide a foundation for improving the applicability of colored asphalt pavement in cold regions.Design/methodology/approachIn the study, three kinds of colorants (iron oxide red, iron oxide yellow, iron oxide green) were used to compare the influence of different colorants amounts and different colorants kinds on the service performance for colored asphalt pavement in cold regions. According to the characteristics of low temperature in cold regions, the effects of different colorants on the low temperature performance for colored asphalt pavement were studied.FindingsThe study shows that different colorants have different effects on the service performance of colored asphalt pavement. The high temperature performance increases with the increase of the colorants amount, but the low temperature performance is opposite. Additionally, the yellow colored asphalt pavement has more advantages of low temperature adaptation than the red and green colored asphalt pavement.Originality/valueThe study results provide a certain theoretical foundation for the application of colored asphalt pavement in cold regions and have certain value and significance for the further development of colored asphalt pavement.