Decreasing Temperature Research Articles

Unveiling the Carrier Dynamics of Perovskite Light-Emitting Diodes via Transient Electroluminescence.

Perovskite light-emitting diodes (PeLEDs) have garnered significant attention due to their outstanding optoelectronic properties. However, investigating carrier transport and recombination behavior during device operation poses persistent challenges. In this study, we explore the impact of additive and interface engineering on device performance using transient electroluminescence (TREL). Polyethylene glycol (PEG) induces the formation of square-faceted nanocrystals with a homogeneous size distribution and extended fluorescence lifetime. Consequently, these PeLEDs exhibit remarkable stability. Additionally, employing an electron transport layer of 2,4,6-tris[3-(diphenylphosphino)phenyl]-1,3,5-triazine (PO-T2T), which has a better match to the energy bands of the perovskite layer and a higher carrier mobility, allows for lower turn-on voltage and faster response but also suffers from a short decay time and poor stability. Moreover, low-temperature TREL characterization shows that the carrier mobility is also significantly suppressed with decreasing temperature, which reduces the transient response speed.

Thermal Runaway Characteristics of Ni-Rich Lithium-Ion Batteries Employing Triphenyl Phosphate-Based Electrolytes

Abstract Enhancing the safety performance of high-energy-density lithium-ion batteries is crucial for their widespread adoption. Herein, a cost-effective and highly efficient electrolyte additive, triphenyl phosphate (TPP), demonstrates flame-retardant properties by scavenging hydrogen radicals in the flame, thereby inhibiting chain reactions and flame propagation to enhance the safety performance of graphite/LiNi0.8Co0.1Mn0.1O2 (Gr/NCM811) pouch cells. The results reveal that the capacity retention of cells without flame retardants, and those with the addition of 1 wt%, 3 wt%, 5 wt%, and 10 wt% TPP is 96.4%, 92.1%, 84.15%, 40.8%, and 12.4% (at 1/2C 300 cycles), respectively. Furthermore, compared to cells without flame retardants, the highest temperature during thermal runaway (TR) decreases by 8.3%, 26.9%, 35.1%, and 38.8% with the addition of 1 wt%, 3 wt%, 5 wt%, and 10 wt% TPP, respectively. Through comprehensive analysis of the impact of flame-retardant additives on battery electrochemical performance and safety, it is determined that the optimal addition amount is 3 wt%. At this level, there are no significant flames during battery abuse, the triggering temperature for TR increases by 26.6 ℃, and the maximum temperature decreases by 157 ℃. Moreover, even after 300 cycles at 1/2C, a capacity of 814.5 mAh is retained, with a capacity retention rate of 84.1%. This study provides valuable insights into mitigating TR in high-energy-density power batteries.

Effect of liquid-vapor two-phase flow maldistribution on the thermal performance of brazed plate heat exchangers

The effect of liquid-vapor two-phase flow maldistribution on the thermal performance of brazed plate heat exchangers (BPHEs) is investigated experimentally and numerically. The two-phase refrigerant flow distributions among different channels of the BPHEs are first experimentally quantified based on the infrared radiation images of the heat exchanger sidewalls. To assess the performance degradation due to two-phase flow maldistribution, the thermal performance of the maldistributed BPHEs is measured and compared with that of the uniform-distributed BPHEs, predicted using an experimentally validated BPHE model. Several factors that affect the performance degradation are analyzed, including refrigerant inlet vapor quality and flow rate, exit superheat, and water-side flow distribution. The results show that, under the tested conditions, the two-phase refrigerant flow maldistribution causes up to a 29.8 % degradation in heat exchanger capacity and a 4 K decrease in evaporation temperature. Furthermore, the vulnerability of the BPHEs to two-phase flow maldistribution is significantly influenced by the operating conditions. This is closely related to the varying size ratios of superheated and two-phase regions within the BPHEs under different operating conditions. Reducing the refrigerant exit superheat is verified to help overcome the adverse effect brought by the flow maldistribution in the evaporators, but brings challenges in the system control. Matching the flow distributions of liquid refrigerant and water also proves beneficial to the BPHE evaporators.

The effect of an auxiliary spring on the decrease of contact resistance and contact temperature for power automotive connector

Power automotive connectors used to connect two electrical systems in an electric vehicle should resist the rising of electric power or electric current. The latter can cause a rise in contact temperature by the Joule effect and can damage a connector improperly designed. The purpose of this work is to study experimentally and numerically the influence of the addition of a second spring on the ability of a power connector to transmit a high current. For this reason, an experimental test has been held on a connector without a second spring to measure contact resistance and contact temperature; then, a finite element model FEM of this connector was developed to compare and validate the numerical results with the experimental results. In addition, another FE model with a second spring was used to minimize contact resistance and contact temperature. Moreover, a theoretical model has shown its effectiveness in contact temperature and contact area calculations; it provides good agreement with experimental and numerical results. Numerical results show that the effect of the addition of a 2nd spring on the decrease of the contact temperature and contact resistance is significant. In addition, the thermo-electrical analysis by finite element shows that the current limit supported by a power connector with an auxiliary spring will equal twice the current supported by a power connector with one spring. FE mechanical analysis shows that the maximum mechanical stress in the connector with an auxiliary spring remains lower than the 2nd spring material yield stress. Finally, experimental and numerical results are in good agreement.

Integrated cellular response of the zebrafish (Danio rerio) heart to temperature change.

A decrease in environmental temperature represents a challenge to the cardiovascular system of ectotherms. To gain insight into the cellular changes that occur during cold exposure and cold acclimation we characterized the cardiac phosphoproteome and proteome of zebrafish following 24 h or one week exposure to 20 oC from 27 oC; or at multiple points during six weeks of acclimation to 20 oC from 27 oC. Our results indicate that cold exposure causes an increase in mitogen-activated protein kinase signaling, the activation of stretch sensitive pathways, cellular remodeling via ubiquitin-dependent pathways, and changes to the phosphorylation state of proteins that regulate myofilament structure and function including desmin and troponin T. Cold acclimation (2-6 weeks) led to a decrease in multiple components of the electron transport chain through time, but an increase in proteins for lipid transport, lipid metabolism, the incorporation of polyunsaturated fatty acids into membranes and protein turnover. For example, there was an increase in the levels of apolipoprotein C, prostaglandin reductase-3, and surfeit locus protein 4, involved in lipid transport, lipid metabolism, and lipid membrane remodeling. Gill opercular movements suggests that oxygen utilization during cold acclimation is reduced. Neither the amount of food consumed relative to body mass nor body condition were affected by acclimation. These results suggest that while oxygen uptake was reduced, energy homeostasis was maintained. This study highlights that the response of zebrafish to a decrease in temperature is dynamic through time and that investment in the proteomic response increases with the duration of exposure.

Insights into corrosion inhibition of aluminum in hydrochloric acid solutions using expired cephalosporins and klavox: Chemical, electrochemical and theoretical approaches

The inhibitory efficacy of two expired antibiotic drugs namely, cephalosporin and klavox against corrosion of aluminum in 1.0 M HCl solution was investigate utilizing potentiodynamic polarization (PDP) impedance spectroscopy (EIS) and weight reduction (WR) methodologies. It was discovered that the two expired drugs act as excellent inhibitors and the inhibition efficacy increases as the drug concentration increases and the temperature decreases. The inhibition efficacy reached 97.62 % and 99.42 % at 900 ppm of cephalosporin and klavox at 298 K, respectively. Expired drugs act as a mixed type inhibitor, controlling primarily the anodic and cathodic process, as evidenced by the PDP curves. According to EIS analysis, the charge transfer resistance values increased with increasing inhibitor concentration. The adsorption isotherm demonstrates that the expired drugs become active by physical adsorption on the Al surface, and their adsorption obeys the Langmuir isotherm. Through quantum chemistry calculations, the relationship between the inhibition properties and molecular structure was studied.

Thermal properties and decomposition products of modified cotton fibers by TGA, DSC, and Py–GC/MS

The thermal properties and pyrolysis decomposition paths of cotton fibers modified by different chemical treatments, a conventional functionalization with silane and a novel sulphation-phosphorylation approach, were studied. The effects on the fibers thermal behavior and decomposition products were investigated. The cotton fibers were characterized before and after the surface treatments by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and pyrolysis/gas chromatography–mass spectrometry (Py/GC–MS). Morphological investigation was also performed by SEM/EDS analysis to assess the treatment effects on the cotton fibers’ surface. The silanization increases the cotton hydrophobicity and thermal stability, changing the pyrolysis mechanism, favoring depolymerization over dehydration and charring. On the contrary, sulphation-phosphorylation methods cause a decrease in the onset temperature and an increase of fire resistance, and charring yield. Thermal decomposition temperatures, weight losses, and pyrolysis mechanisms and products, were fully analyzed. The results can open the way on the use of modified cotton fibers in industrial fields where fireproofing is strongly desired.

Lauric acid based form-stable phase change material for effective electronic thermal management and energy storage application

Poor thermal management in electronic systems can lead to higher junction temperatures, accelerating failure mechanisms and reducing component lifespan. Integrating efficient thermal management techniques, such as heat sinks, is essential for ensuring durability and efficiency of electronic equipment. Heat sinks have limited capacity, but integrating phase change materials (PCMs) enhances cooling performance by harnessing latent heat storage. However, leakage and low thermal conductivity limit PCM's effectiveness. The current study developed highly conductive leakage-proof PCMs based composites using an ultrasonic and vacuum impregnation method with lauric acid as base, hexagonal boron nitride and expanded graphite as additives. The results demonstrate persistence of chemical integrity, as proven by FTIR analysis, and complete encapsulation of PCMs inside the expanded graphite structures. The form-stable composite PCMs exhibit a 450% increase in thermal conductivity and 77% photo-transmittance decrease compared to base PCMs. Despite a trade-off of a 11.5% reduction in latent heat, the composite demonstrates thermal stability up to 220 °C. Further, excellent chemical and thermal reliability is maintained even after 500 cycles. Furthermore, in thermal management for heat sink, the form stable composite efficiently dispersed heat, resulting in a 16 °C decrease in peak temperature compared to the heat sink without the composite.

Nutritional Composition of Post-Catastrophic Foods.

In addition to current challenges in food production arising from climate change, soil salinization, drought, flooding, and human-caused disruption, abrupt sunlight reduction scenarios (ASRS), e.g., a nuclear winter, supervolcano eruption, or large asteroid or comet strike, are catastrophes that would severely disrupt the global food supply and decimate normal agricultural practices. In such global catastrophes, teragrams of particulate matter, such as aerosols of soot, dust, and sulfates, would be injected into the stratosphere and block sunlight for multiple years. The reduction of incident sunlight would cause a decrease in temperature and precipitation and major shifts to climate patterns leading to devastating reductions in agricultural production of traditional food crops. To survive a catastrophic ASRS or endure current and future disasters and famines, humans might need to rely on post-catastrophic foods, or those that could be foraged, grown, or produced under the new climate conditions to supplement reduced availability of traditional foods. These foods have sometimes been referred to as emergency, alternate, or resilient foods in the literature. While there is a growing body of work that summarizes potential post-catastrophic foods and their nutritional profiles based on existing data in the literature, this article documents a list of protocols to experimentally determine fundamental nutritional properties of post-catastrophic foods that can be used to assess the relative contributions of those foods to a balanced human diet that meets established nutritional requirements while avoiding toxic levels of nutrients. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Total digestible glucans Basic Protocol 2: Apparent protein digestibility Basic Protocol 3: Vitamins B1, B3, B9, C, and D2 by HPLC Basic Protocol 4: Total antioxidant activity (DPPH-scavenging activity) Basic Protocol 5: Total phenolic compounds (Folin-Ciocalteu reagent method) Basic Protocol 6: Mineral content by ICP-OES.

The Influence of ENSO Diversity on Future Atlantic Tropical Cyclone Activity

Abstract El Niño–Southern Oscillation (ENSO) influences seasonal Atlantic tropical cyclone (TC) activity by impacting environmental conditions important for TC genesis. However, the influence of future climate change on the teleconnection between ENSO and Atlantic TCs is uncertain, as climate change is expected to impact both ENSO and the mean climate state. We used the Weather Research and Forecasting Model on a tropical channel domain to simulate 5-member ensembles of Atlantic TC seasons in historical and future climates under different ENSO conditions. Experiments were forced with idealized sea surface temperature configurations based on the Community Earth System Model (CESM) Large Ensemble representing: a monthly varying climatology, eastern Pacific El Niño, central Pacific El Niño, and La Niña. The historical simulations produced fewer Atlantic TCs during eastern Pacific El Niño compared to central Pacific El Niño, consistent with observations and other modeling studies. For each ENSO state, the future simulations produced a similar teleconnection with Atlantic TCs as in the historical simulations. Specifically, La Niña continues to enhance Atlantic TC activity, and El Niño continues to suppress Atlantic TCs, with greater suppression during eastern Pacific El Niño compared to central Pacific El Niño. In addition, we found a decrease in the Atlantic TC frequency in the future relative to historical regardless of ENSO state, which was associated with a future increase in northern tropical Atlantic vertical wind shear and a future decrease in the zonal tropical Pacific sea surface temperature (SST) gradient, corresponding to a more El Niño–like mean climate state. Our results indicate that ENSO will remain useful for seasonal Atlantic TC prediction in the future.

Hypothermia and rewarming times during general anesthesia in Hispaniolan amazon parrots (Amazona ventralis): a comparative study between isoflurane, sevoflurane and desflurane

ObjectiveTo evaluate induced hypothermia and rewarming times in Hispaniolan Amazon parrots (HAP) anesthetized using isoflurane, sevoflurane, or desflurane, and to describe selected cardiovascular and respiratory effects. Study designRandomized, balanced, crossover experimental study AnimalsTwelve adult HAP (Amazona ventralis) MethodsParrots were premedicated with intramuscular butorphanol (0.5 mg kg–1) and anesthetized with the three inhalants with a 7 day washout period between events. Anesthesia was induced using isoflurane at 4 vol%, sevoflurane at 6 vol% or desflurane 12 vol% carried in oxygen, delivered via face mask. Following orotracheal intubation, anesthesia maintenance was with end-tidal concentrations of 1.4–2% (FE´Iso), 2.4–3% (FE´Sevo) and 8.5–9.2% (FE´Des). Hypothermia was defined as an esophageal temperature (BT) below 37.8 ºC. External heat support was provided when BT dropped to 37.5 ºC. Time for temperature decrease from 38.9 ºC to 37.5 ºC (T1), time to first increase in BT above 37.5 ºC (T2), and time from external heat support to achieving 38.9 ºC (T3) were recorded and compared via Friedman tests with post hoc Dunn’s test. Heart rate, respiratory rate, end-tidal carbon dioxide, amongst other variables, were evaluated. ResultsAll inhalants caused hypothermia (T1): isoflurane; 12 (2–37) minutes [median (range)], sevoflurane; 12 (4–18) minutes, desflurane; 11.5 (6–24) minutes, with no significant differences between treatments (p > 0.05). T2 was significantly (p = 0.042) longer for sevoflurane compared to desflurane, but not isoflurane. Transient apnea was observed with all inhalants, including 25% of birds anesthetized with sevoflurane. Second-degree atrioventricular block and ventricular escape beats occurred with all inhalants with hypothermia potentially exacerbating cardiac arrhythmias. Conclusion and clinical relevanceHypothermia rapidly developed in butorphanol-sedated Hispaniolan Amazon parrots anesthetized using isoflurane, sevoflurane or desflurane. Sevoflurane prolonged warming time. Hypothermia may be associated with an increased likelihood of bradyarrhythmia in parrots anesthetized with inhalants.

Computational study of homogeneous–heterogeneous reactions in bioconvective third-grade material flow

The flow of third-grade nanofluid over a stretched surface is analyzed with a particular focus on the transport of heat due to melting by taking into account both homogeneous and heterogeneous reactions. To account for various effects, the energy equation incorporating viscous dissipation, Joule heating and radiation is considered, as well as the influence of thermophoresis and Brownian motion. A similarity transformation is used to simplify the expressions such that the model is analyzable. Utilizing the homotopic technique, series solutions are obtained, and a convergence result is established. Our investigation based on this series solution explores the impact of different factors on the flow model, and demonstrates that increasing the melting parameter leads to a decrease in temperature, entropy rate and concentration, while to an increase in velocity.

Correlation effect and sodium diffusion in silicate glass: molecular dynamics simulation

We conducted a molecular dynamics simulation to investigate the diffusion in sodium silicate glass. The result shows that the sodium diffusion is accompanied with the correlation effect that Na atoms often leave and then return to the starting polyhedron. We establish the expression for diffusion constant D via hopping rate γ, correlation factor F and average square distance per visiting polyhedron d2. The results show that unlike diffusion in crystal, F decreases with decreasing temperature. Moreover, F is dependent with SiO2 content of glass, and D exhibits a linear dependence on the product Fγ.

Study on the mechanism of rapid densification and structural evolution of C/C composites by cooling pyrolysis

A large thermal gradient about 190 ℃/cm was established in the thickness direction of preform and the cylindrical carbon/carbon composites with radial gradient pyrocarbon (PyC) distribution were rapidly prepared via the cooling pyrolysis technology in the high temperature surface based on the large thermal gradient chemical vapor infiltration (CPTHTS-LTGCVI). The decrease of initial temperature and the increase of cooling rate both contribute to the opening of closed pore and pore expansion, which are conducive to improving the densification degree. Moderate initial temperature (about 1130℃) and cooling rate (10 ℃/5 h) are optimal to rapidly preparing C/C composites with good density uniformity. For the whole cylindrical C/C composites, the faster the cooling rate, the higher the density and density uniformity, the fewer the super macropores. As the cooling rate is 10 ℃/2.5 h, the density of sample can reach 1.57 g/cm3 within 50 h, and the carbon yield in the first stage and accumulation can reach 84 % and 50 %, respectively. From the inner wall (IW) to the outer wall (OW), there are three successive regions about RL, RL+SL and SL PyC with gradually weakened texture, which is related to the insufficient pyrolysis caused by the decreased temperature and increased concentration, and the aromatization caused by the extended gas retention time. The edge dislocations and non-coherent sub-grain boundaries of PyC may be related to the distorted aromatic carbon planes containing five-membered rings. The edge dislocations may be the main reason of texture reduction and structural evolution of PyC.

Modulation of the Superconducting Phase Transition in Multilayer 2H-NbSe2 Induced by Uniform Biaxial Compressive Strain.

Strain is a powerful tool for tuning the properties of two-dimensional materials. Here, we investigated the effects of large, uniform biaxial compressive strain on the superconducting phase transition of multilayered 2H-NbSe2 flakes. We observed a consistent decrease in the critical temperature of NbSe2 flakes induced by the large thermal compression of a polymeric substrate (>1.2%) at cryogenic temperatures. For thin flakes (∼10 nm thick), a strong modulation of the critical temperature up to 1.5 K is observed, which monotonically decreases with increasing flake thickness. The effects of biaxial compressive strain remain significant even for relatively thick samples up to 80 nm thick, indicating efficient transfer of strain not only from the substrate to the flakes but also across several van der Waals layers. This work demonstrates that compressive strain induced from substrate thermal deformation can effectively tune phase transitions at low temperatures in 2D materials.

Utilization of bamboo biochar as a multi-functional filler of flexible poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide) bioplastic

Biodegradable poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide) (PLLA-PEG-PLLA) triblock copolymer could potentially be used in bioplastic applications because it is more flexible than PLLA. However, investigations into modifying PLLA-PEG-PLLA with effective fillers are still required. In this work, bamboo biochar (BC) was used as an eco-friendly and cost-effective filler for the flexible PLLA-PEG-PLLA. The influences of BC addition on crystallization properties, thermal stability, hydrophilicity, and mechanical properties of the PLLA-PEG-PLLA were explored and compared to those of the PLLA. The PLLA-PEG-PLLA matrix and BC filler were found to have strong interfacial adhesion and good phase compatibility, while the PLLA/BC composites displayed weak interfacial adhesion and poor phase compatibility. For the PLLA-PEG-PLLA, the addition of BC induced a nucleation effect that was characterized by a decrease in the cold crystallization temperature from 76 to 71–75 °C and an increase in the crystallinity from 18.6 to 21.8–24.0%; however, this effect was not observed for the PLLA. When compared to pure PLLA-PEG-PLLA, the PLLA-PEG-PLLA/BC composites displayed greater thermal stability, tensile stress, and Young’s modulus. Temperature at maximum decomposition rate (Td,max) of PLLA end-blocks increased from 315 to 319–342 °C. Ultimate tensile stress of PLLA-PEG-PLLA matrix improved from 14.5 to 16.2–22.6 MPa and Young’s modulus increased from 220 to 280–340 MPa. Based on the findings, the crystallizability, thermal stability, and mechanical properties of the flexible PLLA-PEG-PLLA bioplastic were all enhanced by the use of BC as a multi-functional filler.

Numerical assessment of hydrothermal and entropy generation characteristics of graphene quantum dots nanofluid in a microchannel heat sink incorporating secondary channels and ribs

Efficient heat dissipation from electronic chips is essential for enhancing their performance and longevity. Significant progress has been achieved through the introduction of nanofluids and microchannel heat sinks. However, there is still a need for nanofluids that demonstrate exceptional thermal properties and stability. Graphene quantum dots nanofluid, an innovative carbon-based coolant with zero-dimensional nanostructures, presents promising features such as excellent chemical stability, surfactant-free preparation, superior thermal properties, and minimal impact on rheological characteristics. This study explores, for the first time, the hydrothermal behavior and entropy generation of graphene quantum dots nanofluid in a microchannel heat sink comprising secondary flow channels and ribs. To this end, a three-dimensional conjugate heat transfer model is built using ANSYS Fluent software, and the governing equations are solved using the finite volume method. The simulations are carried out considering temperature-dependent thermophysical properties under different concentrations ranging from 0 to 0.5 % and Reynolds numbers ranging from 100 to 500. The results reveal that the maximum bottom wall surface temperature decreases by 5.88 K, while the heat transfer coefficient improves by 24.9 % compared to the base fluid. Moreover, the total entropy generation reduces by 14.7 %. On the other hand, the pressure drop increases by 43 %. Overall, the highest increment in Performance Evaluation Criteria is 10.8 % at a Reynolds number of 100 and a concentration of 0.5 %, making this particular condition suitable for practical applications.

Preparation of poly(methacrylic acid) grafted on SiO2-NH2/PSF composite membranes for amlodipine removal

Firstly, the SiO2 microspheres were prepared by Stӧber method, and then modified by 3-Aminopropyltrimethoxysilane (KH-540) to introduce –NH2 onto the microspheres. Then, SiO2-NH2 microspheres were mixed into polysulfone casting solution, and SiO2-NH2/PSF composite membrane was prepared by the phase conversion method. On this basis, the functional adsorbent SiO2-NH2/PSF-g-PMAA was prepared by grafting polymerization of methacrylic acid (MAA) as a functional monomer using –NH2/S2O8 2− surface initiation system. The samples were characterized by Fourier infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), the Brunauer–Emmett–Teller (BET) and weighing method. The adsorption properties of amlodipine (ADP) by functional adsorbents were investigated, and the adsorption mechanism was further studied. The results show that the adsorption reaches equilibrium at 180 min, and the adsorption kinetics can be well fitted by the pseudo-second-order model. The adsorption capacity of SiO2-NH2/PSF-g-PMAA for amlodipine in methanol with 1.4 mg/mL at 15 °C is 137 mg/g. The adsorption ability increases with the decrease of ionic strength and temperature via the hydrogen bond and ionic interactions, and the adsorption of ADP by SiO2-NH2/PSF-g-PMAA is consistent with the D-R adsorption isotherm model. Thermodynamic parameters imply that adsorption is a spontaneous and exothermic process.

De-icing behavior and efficiency of electrothermal film surfaces with different non-wettability in low-temperature flow field

The electrothermal anti-/de-icing technology with excellent de-icing efficiency has been widely applied to eliminate the icing threat on airfoil, whose essence is heat transfer process between heating surface and ice. However, the heat transfer behavior and interfacial transformation form of ice accretion are indistinct on traditional non-superhydrophobic surfaces and rapidly-developed superhydrophobic surfaces in the low-temperature flow field. Therefore, the heat transfer and solid-ice interface transform behavior on film heater surface were explored in this work by analyzing the temperature-rising performance and de-icing characteristics of hydrophobic films (HPoF) and superhydrophobic films (SHPoF) in the icing wind tunnel. The results indicated that the faster wind speed enhanced the convection and radiant heat loss of the film heater, and the peak temperature of film heater was directly affected by the environment temperature. Moreover, the SHPoF had lower de-icing consumption than HPoF in an environment without wind field, which was less related to the ice accretion. However, the de-icing form transformed from shearing to shedding mode with the growth of ice accretion under wind field conditions. In the shearing de-icing mode, the lower environment temperature and faster wind speed caused longer de-icing time, whereas the deicing time shortened with the decrease of environment temperature in the shedding mode. When the icing time was 1 min, the de-icing time of SHPoF increased by 12.25%–25.73 % due to the slower heat transfer at the solid-gas-ice interface compared to the solid-liquid-ice interface of HPoF. With the further increase of icing time, the ice accretion was removed after the melt of interfacial ice. The less solid-ice contact points were present at the solid-gas-ice interface on SHPoF surfaces, resulting in energy saving of 20.16%–40.46 % compared to HPoF surfaces. Therefore, the electrothermal superhydrophobic de-icing technology exhibited energy-efficient characteristics when the self-weight of ice is the primary driving force for de-icing process.

Study on water-salt phase transition of saline soils during freezing

As the temperature decreases, when the freezing temperature is reached, the solution in the pores of saline soil undergoes ice crystallization and salt crystallization phenomena. Theoretical and experimental studies have been carried out in order to investigate the behaviour of water-salt phase transitions within the pores of saline soils. Firstly, the theoretical expression for the initial crystallization radius is given from the thermodynamic theory by considering the interphase chemical potential equilibrium and the Young-Laplace equation, and the relationship between the initial crystallization radius and temperature as well as the initial salt content is analyzed. Then, a theoretical model to predict the pore solution content and crystal content was developed in conjunction with the Van Genuchten soil-water characteristic curve model, and the water-salt phase transition behaviour of saline soils was analyzed by numerical calculations. Finally, the validity of the theoretical model was verified by a saline soil freezing test. The results show that the water-salt phase transition behaviour of the solution within the pores of saline soils is affected by temperature and initial salt content, and the water-salt phase transition behaviour mainly occurs at the early stage of freezing. Salt lowers the freezing temperature of the soil; the higher the salt content, the lower the freezing temperature, and the presence of salt inhibits the growth of ice crystals. As the temperature decreases, the precipitation of ice salt crystals during the phase transition of the soil pore solution reduces the soil porosity and decreases the channels for ion migration, resulting in a gradual increase in the soil pore volume ratio.