Sudden Temperature Research Articles

Photolipid excitation triggers depolarizing optocapacitive currents and action potentials

Optically-induced changes in membrane capacitance may regulate neuronal activity without requiring genetic modifications. Previously, they mainly relied on sudden temperature jumps due to light absorption by membrane-associated nanomaterials or water. Yet, nanomaterial targeting or the required high infrared light intensities obstruct broad applicability. Now, we propose a very versatile approach: photolipids (azobenzene-containing diacylglycerols) mediate light-triggered cellular de- or hyperpolarization. As planar bilayer experiments show, the respective currents emerge from millisecond-timescale changes in bilayer capacitance. UV light changes photolipid conformation, which awards embedding plasma membranes with increased capacitance and evokes depolarizing currents. They open voltage-gated sodium channels in cells, generating action potentials. Blue light reduces the area per photolipid, decreasing membrane capacitance and eliciting hyperpolarization. If present, mechanosensitive channels respond to the increased mechanical membrane tension, generating large depolarizing currents that elicit action potentials. Membrane self-insertion of administered photolipids and focused illumination allows cell excitation with high spatiotemporal control.

Research on modified expanded graphite/eutectic salt composite phase change material in cold chain transportation

Attention to the use of phase change materials (PCMs) in cold chain transportation has increased in recent years. In this work, a form-stable composite phase change material (CPCM) prepared by a novel eutectic salt (Na2SO4·10H2O-MgSO4·7H2OH2O) PCM composite with modified expanded graphite (MEG) was investigated. The hydrophilicity of expanded graphite (EG) and its compatibility with the eutectic salts were improved by coating SiO2. The results showed that microstructure of the EG was maintained after modification, and adsorption of the PCM by the MEG was 55.23 wt% higher than that of the EG. The CPCM with 20 wt% MEG exhibit a high enthalpy of 180.8 J/g, the phase transition temperature of −5.6 °C and a high thermal conductivity of 5.183 W/(m·K). The thermal conductivity of CPCM was 8 times as large as that of the PCM. Moreover, the thermal performance of the CPCM was small change after 200 thermal cycling, exhibiting good thermal cyclic reliability. Besides, a potential application test of the form-stable CPCM was performed through a low temperature insulation box. It showed that form-stable CPCM can control sudden temperature fluctuation and maintain stable temperature for longer time inside the insulation box.

Ecophysiological responses of Liolaemus arambarensis juveniles to experimental temperature variations

Climate change increasingly influences the loss of biodiversity, especially in ectothermic organisms, which depend on environmental temperatures to obtain heat and regulate their life cycle. Studies that aim to understand the impact of temperature variation are important to better understand the possible impacts generated on the homeostasis of ectothermic organisms. Our objective was to characterize the responses of juvenile Liolaemus arambarensis lizards to abrupt changes in temperature, quantifying markers of body condition, intermediary and hormonal metabolism and oxidative balance. We collected 45 juvenile individuals of L. arambarensis (winter: 20 and summer: 25) in Barra do Ribeiro, Brazil. We transported the animals to the laboratory, where they were acclimatized for five days at a temperature of 20 °C, then divided and exposed to temperatures of 10 °C, 20 °C, 30 °C and 40 °C for 24 h. After exposure, the animals were euthanized and the brain, caudal muscle, thigh, and liver tissues were extracted for quantification of biomarkers of metabolism (glycogen and total proteins) and oxidative balance (acetylcholinesterase, superoxide dismutase, catalase, glutathione-S-transferase and lipoperoxidation) and plasma for corticosterone quantification. The results show that L. arambarensis is susceptible to sudden temperature variations, where higher temperatures caused greater activity of antioxidant enzymes, increased lipoperoxidation and higher plasma levels of corticosterone in animals eliminated in winter. The present study demonstrated that abrupt changes in temperature could significantly modify the homeostatic mechanisms of animals, which could lead to oxidative stress and a potential trade-off between survival and growth/reproduction. In this context, the organism mobilizes energy resources for survival, with possible damage to growth and reproduction. Demonstrate that a change in temperature can be a potential factor in extinction for a species given the profile of global climate change.

Functional PCA and deep neural networks-based Bayesian inverse uncertainty quantification with transient experimental data

This work focuses on developing an inverse uncertainty quantification (IUQ) process for time-dependent responses, using dimensionality reduction by functional principal component analysis (PCA) and deep neural network (DNN)-based surrogate models. The demonstration is based on the IUQ of TRACE physical model parameters using the FEBA benchmark transient experimental data on peak cladding temperatures during reflooding. The quantity-of-interest (QoI) is time-dependent peak cladding temperature (PCT) profiles. Conventional PCA can hardly represent the data precisely due to the sudden temperature drop at the time of quenching. As a result, a functional alignment method is used to separate the phase and amplitude information in the PCT profiles before conventional PCA is applied for dimensionality reduction. The resulting PC scores are then used to build DNN-based surrogate models to significantly reduce the computational cost in Markov Chain Monte Carlo sampling, while the code/interpolation uncertainty is accounted for using Bayesian neural networks. We compared four IUQ processes with different dimensionality reduction methods and surrogate models. The proposed approach has demonstrated the best performance in reducing the dimensionality of the transient PCT profiles. This approach also produces the posterior distributions of the physical model parameters with which the model predictions have the best agreement with the experimental data.

Light-mediated temperature susceptibility of kelp species (Agarum clathratum, Saccharina latissima) in an Arctic summer heatwave scenario

Abstract Kelps (Phaeophyceae, Laminariales) are ecosystem engineers along Arctic rocky shores. With ongoing climate change, the frequency and intensity of marine heatwaves are increasing. Further, extensive meltwater plumes darken Arctic fjords. Assessing the effect of a sudden temperature increase at the cold-distribution limit of cold-temperate kelp species, we compared the responses of two kelp species (Agarum clathratum, Saccharina latissima) to realistic Arctic summer heatwave scenarios (4–10°C) under low- and high-light conditions (3; 120 μmol photons m−2 s−1) for 12 days. We found high-light causing physiological stress in both species (e.g., lower photosynthetic efficiency of photosystem II), which was enhanced by cold and mitigated by warm temperatures. Under low-light conditions, we found no temperature response, probably due to light limitation. Both species acclimated to light variations by adjusting their chlorophyll a concentration, meeting cellular energy requirements. A. clathratum had ~150% higher phlorotannin concentrations than S. latissima, possibly acting as herbivore-deterrent. Our findings suggest competitive advantages of kelps on different Arctic coasts with ongoing warming: A. clathratum has advantages in future areas, with low-light intensities, and possibly high grazing pressure and S. latissima in areas with high-light intensities and low grazing pressure. Species composition changes might have cascading consequences on ecosystem functioning.

Climate-change literacy of first year prospective physics teacher about long dry season phenomenon in Indonesia

Indonesia has characteristics of increasing temperatures that have yet to be widely known. Sudden temperature changes have brought many losses to Indonesians. The study was intended to analyze the level of scientific literacy on the climate-change material for prospective physics teachers in Indonesia. The study employs a qualitative methodology. The study also utilized descriptive analysis techniques by administering surveys to gather participant data. This study uses descriptive analysis techniques through the administration of surveys to collect data from participants. Increased emissions of greenhouse gases are a contributing factor to changes in temperature and climate. The escalation of greenhouse gas emissions in Indonesia leads to climate change as these gases envelop the Earth and trap the sun's heat, intensifying the greenhouse effect. The outcome entails elevated mean temperatures, alterations in precipitation patterns, and occurrences of severe weather events such as floods and droughts. Evaluating climate or temperature changes necessitates education. Education imparts knowledge about the significance of safeguarding the planet to maintain its well-being. Education plays a crucial role in addressing the challenge of climate change, particularly the Sustainable Development Goals (SDGs).

Numerical analysis of thermal runaway process of lithium-ion batteries considering combustion

We studied the thermal runaway process of lithium-ion batteries (LIBs) caused by thermal abuse, with a particular focus on the effects of combustion. First, we observed a gradual increase in battery temperature during thermal runaway until it reached 190 °C, at which point it sharply rose to approximately 500 °C. However, thermal runaway induced by combustion was characterized by a sudden temperature increase at lower temperatures. Second, we analyzed the internal reactions occurring in a location far from the heat source resulting from combustion. We found that the solid electrolyte interface (SEI) decomposition contributed to nearly 90 % of the heat generated at lower temperatures, while the positive electrode-electrolyte reaction emerged as the major heat source at temperatures exceeding 195 °C. Finally, we also examined the internal reactions in a location close to the heat source caused by combustion. We identified that the internal reactions initiated at around 50 °C and occurred simultaneously. The heat generated by the negative electrode-electrolyte and positive electrode-electrolyte reactions accounted for approximately 47 % and 46 % of the total heat during thermal runaway, respectively. Consequently, we concluded that combustion accelerates thermal runaway in LIBs. We expect this study to enhance the prediction of heat propagation during thermal runaway.

A Synergistic View on Osmolyte's Role against Salt and Cold Stress in Biointerfaces.

We present our perspective on the role of osmolytes in mitigating abiotic stresses such as hypersalinity and sudden temperature changes. While the stabilizing effect of osmolytes on protein tertiary structures has been extensively studied, their direct impact on abiotic stress factors has eluded mainstream attention. Via highlighting a set of recent success stories of a joint venture of computer simulations and experimental measurements, we summarize the mechanistic insights into osmolytic action, particularly in the context of salt stress and combined cold-salt stress at the interface of biomolecular surfaces and saline environments. We stress the importance of chemical specificity in osmolytic activity, the interplay of differential osmolytic behaviors against heterogeneous salt stress, and the capability of osmolytes to adopt combined actions. Additionally, we discuss the potential of incorporating nanomaterial-based systems to enrich our understanding of osmolyte bioactions and facilitate their practical applications. We anticipate that this discourse will inspire interdisciplinary collaborations and motivate further investigations on osmolytes, ultimately broadening their applications in the fields of health and disease.

Irreparable Interphase Chemistry Degradation Induced by Temperature Pulse in Lithium-Ion Batteries.

While it is widely recognized that the operating temperature significantly affects the energy density and cycle life of lithium-ion batteries, the consequence of electrode-electrolyte interphase chemistry to sudden environmental temperature changes remains inadequately understood. Here, we systematically investigate the effects of a temperature pulse (T pulse) on the electrochemical performance of LiNi0.8 Mn0.1 Co0.1 O2 (NMC811) pouch full cells. By utilizing advanced characterization tools, such as time-of-flight secondary-ion mass spectrometry, we reveal that the T pulse can lead to an irreversible degradation of cathode-electrolyte interphase chemistry and architecture. Despite negligible immediate impacts on the solid-electrolyte interphase (SEI) on graphite anode, aggregated cathode-to-anode chemical crossover gradually degrades the SEI by catalyzing electrolyte reduction decomposition and inducing metallic dead Li formation because of insufficient cathode passivation after the T pulse. Consequently, pouch cells subjected to the T pulse show an inferior cycle stability to those free of the T pulse. This work unveils the effects of sudden temperature changes on the interphase chemistry and cell performance, emphasizing the importance of a proper temperature management in assessing performance.

Irreparable Interphase Chemistry Degradation Induced by Temperature Pulse in Lithium‐Ion Batteries

AbstractWhile it is widely recognized that the operating temperature significantly affects the energy density and cycle life of lithium‐ion batteries, the consequence of electrode‐electrolyte interphase chemistry to sudden environmental temperature changes remains inadequately understood. Here, we systematically investigate the effects of a temperature pulse (T pulse) on the electrochemical performance of LiNi0.8Mn0.1Co0.1O2 (NMC811) pouch full cells. By utilizing advanced characterization tools, such as time‐of‐flight secondary‐ion mass spectrometry, we reveal that the T pulse can lead to an irreversible degradation of cathode‐electrolyte interphase chemistry and architecture. Despite negligible immediate impacts on the solid‐electrolyte interphase (SEI) on graphite anode, aggregated cathode‐to‐anode chemical crossover gradually degrades the SEI by catalyzing electrolyte reduction decomposition and inducing metallic dead Li formation because of insufficient cathode passivation after the T pulse. Consequently, pouch cells subjected to the T pulse show an inferior cycle stability to those free of the T pulse. This work unveils the effects of sudden temperature changes on the interphase chemistry and cell performance, emphasizing the importance of a proper temperature management in assessing performance.

Late Triassic–Jurassic bivalve biochronology, palaeogeography and palaeoenvironment of the Junggar Basin, NW China

Abstract The middle Mesozoic of the southern Junggar Basin is a source of abundant Late Triassic–Jurassic non-marine and Early Jurassic marine–littoral bivalves. The bivalve chronology provides a framework for dating the strata and documents Early Jurassic transgressions and the end-Triassic mass extinction in the Junggar Basin. The first occurrences (FOs) and last occurrences (LOs) of Utschamiella cf. tungussica and Utschamiella cf. obrutschevi lie in the basal upper Rhaetian. The FOs of Ferganoconcha sibirica , Ferganoconcha subcentralis , Unio manasensis , Unio mirabilis and Waagenoperna are at, and the FOs of Margaritifera isfarensis , Tutuella rotunda and Tutuella chachlovi adjoin, the base of the middle Sinemurian. The LOs of Yananoconcha hengshanensis and Waagenoperna are at the Lower–Middle Jurassic boundary. The LOs of Psilunio , Cuneopsis and F . subcentralis are near the Middle–Upper Jurassic boundary. Non-marine bivalves disappeared in the late Rhaetian, due to a sudden Norian–Rhaetian temperature drop. New forms did not return until the Sinemurian, when the climate warmed. The transgressions created low-relief terrestrial environments, in which organisms including bivalves thrived, leading to the formation of large quantities of coal, oil and gas. The Junggar Basin shifted from Arctic to subtropical latitudes in the Northern Hemisphere between the Early and Middle Jurassic.

Decay Characteristics of Mechanical Properties of Asphalt Mixtures under Sizeable Wet Temperature Cycle

Asphalt mixtures will inevitably be affected by rainwater and the effect of the wet temperature cycle during a pavement’s life span. Especially in coastal areas such as Guangdong and Hainan in China, asphalt pavement is particularly susceptible to the sizeable wet temperature cycle formed by the high temperature and sudden temperature drop of rainstorms in summer. For this study, we used a homemade sizeable wet temperature cycle environment simulation device to analyze the decay characteristics and the mechanical properties of asphalt pavements in this environment; modified bending and tensile strength and shear strength tests were used to study the decay patterns of shear strength, bending, and tensile strength, and the stiffness modulus of asphalt mixtures with different air voids and different pavement depths under the action of a sizeable wet temperature cycle. In addition, the Grey correlation method was used to analyze the significance of each influencing factor on the decay of mechanical properties, and mathematical fitting was used to establish the prediction equation of the mechanical properties of asphalt mixtures. The results show that with the increase in the number of sizeable wet temperature cycles, the asphalt mixture’s shear strength, flexural tensile strength, and flexural tensile modulus decrease, the degree of decay increases, and the rate of decay gradually slows down. In the case of the same number of sizeable wet temperature cycles, the degree of decay of the asphalt mixtures gradually decreases with increasing depth or decreasing void ratio. After 100 sizeable wet temperature cycles, the maximum values of the decay of shear strength, modulus of strength, and flexural tensile strength were 22.30%, 23.29%, and 32.01%. The importance of the influence of each factor on the decay of the mechanical properties is as follows: the number of sizeable wet temperature cycles > void rate > depth. The prediction equations of the established mechanical properties have a good prediction effect, and the correlation between predicted values and actual values can be up to 0.925. The prediction equations can effectively predict the mechanical properties of asphalt mixtures with different air voids and depths under the action of sizeable wet temperature cycles.

Responses of radial growth of Larix principis-rupprechtii to abrupt warming

To investigate the impacts of abrupt warming on tree growth, we collected tree ring cores from larch (Larix principis-rupprechtii) in three different sites, including Saihanba National Nature Reserve, Pangquangou National Nature Reserve, and Fengning Qiansongba National Forest Park. Based on the tree ring method, Mann-Kendall test was used to examine the occurrence time of temperature rise mutation. We further analyzed the radial growth law of larch before and after the temperature mutation and its correlation with the monthly climate data. The results showed that the sudden temperature rise occurred in the Saihanba area in 1987, the Fengning area in 1989, and the Pangquangou area 1994. Before the sudden warming, there was no significant trend for the radial growth in all the three regions. After the sudden warming, however, it decreased significantly (with a decrease rate of 0.08·10 a-1) in Saihanba area. The radial growth of larch increased significantly in Pangquangou area (with an increase rate of 0.10·10 a-1), while no significant change was observed in the Fengning area. Before the sudden warming, there was a significant positive correlation between the radial growth of larch in the Saihanba area and the highest temperature in May and June. After the sudden warming, there was a significant positive correlation with precipita-tion in July, and a highly significant positive correlation with the standardized precipitation evapotranspiration index(SPEI) from September of the previous year to July. Prior to the sudden warming, there was no significant relationship between the radial growth of larch in the Pangquangou area and monthly climate factors. However, after the sudden warming, a significant positive correlation was found with the lowest temperature in September of the pre-vious year. Before the sudden warming, the radial growth of larch in Fengning area was significantly negatively correlated with the lowest average temperature in July. After the sudden warming, it showed a significant negative correlation with the average and highest temperatures in June. Accordingly, the radial growth of larch in the Saihanba area experienced drought stress following a sudden temperature change. If temperature continues to rise in the future, larch in the Fengning area would also face drought stress. Conversely, warming conditions would be beneficial for the radial growth of larch in the Pangquangou area.

Thermotolerant PGPR consortium B3P modulates physio-biochemical and molecular machinery for enhanced heat tolerance in maize during early vegetative growth

BackgroundGlobal warming and irregular changes in temperature are a serious threat to plant growth with a significant negative impact on yield. Global maize productivity has decreased significantly due to sudden temperature fluctuations and heat waves especially in the regions severely hit by climate change.ResultsThe current study demonstrates the potential of beneficial bacteria for inducing heat tolerance in maize during early growth. Three Bacillus spp. AH-08, AH-67, SH-16, and one Pseudomonas spp. SH-29 showed the ability to grow and exhibited multiple plant-beneficial traits up to 45 ± 2 °C. At temperatures of 45 and 50 °C, Bacillus sp. SH-16 exhibited upregulation of two small heat shock proteins (HSP) of 15 and 30 kDa, while SH-16 and AH-67 showed upregulation of two large HSP of 65 and 100 kDa. Plant-inoculation with the consortium B3P (3 Bacillus + 1 Pseudomonas spp.) was carried out on six hybrid maize varieties pre-grown at 25 ± 2 ºC. Heat shock was applied to 10-day-old seedlings as: 3 h at 38ºC, 48 h recovery period, and then 48 h at 42ºC. The B3P treatment showed significant improvement in the overall plant growth (plant height, root & shoot fresh & dry weight, root and leaf area) with a higher level of CAT, POD, total chlorophyll, and carotenoids, while low concentration of MDA. A non-significant difference was observed in case of total cell protein and amino acids after B3P-treatment under stress. The expression of HSP1 and HSP18 in Malka and YH-5427 while HSP70 and HSP101 were higher in FH-1046 and Gohar as compared to non-inoculated treatment.ConclusionsThese findings indicate that heat-tolerant plant-growth promoting rhizobacteria (Ht-PGPR) exert versatile, multiphasic and differential response to improve plant growth and heat-tolerance in different maize varieties during seedling/ early vegetative growth. Subsequent research will be focused on the field evaluation of these PGPR to see the field and yield response of this consortium under natural temperature fluctuations in field.

Detailed Analysis of the Effects of Viscosity Measurement Errors Caused by Heat Transfer during Continuous Viscosity Measurements under Various Temperature Changes and the Proposed Solution of a Non-Dimensional Parameter Called the Akpek Number

It is extremely important to gather the viscosity behavior of fluids accurately for industries and academia. There is no better method than viscosity measurement to detect changes in the specific characteristics of the materials. However, viscosity measurement is indeed a very sensitive process. In nature, fluids are involved in widely various containers, and they are affected by serious temperature deviations. It is a necessity for viscometers to have the capability to obtain accurate data from all types of containers of fluids even in serious temperature variations in order to understand the natural phenomena inside the fluids. Conventional viscometers mainly neglect the effect of sudden temperature deviations inside the fluids, or they need to use very expensive water bath systems that stabilize the temperature around the test fluids, which is not feasible at all. In this research, the effects of non-uniform temperature fields are analysed detailly to confirm that even in extremely limited amounts, serious viscosity and temperature deviations may occur. Experiments were performed in two parts. The first part was conducted using several thermocouples with different test fluids to find out the effects of thermal conduction and convection. For the second part, particle image velocimetry (PIV) was utilized to comprehend the flow movement within the test fluids. It was shown that even for small volumes and even in very controlled environments, an almost 35% viscosity measurement error (VME) occurs. Finally, as a solution to this problem, a new non-dimensional parameter called the Akpek number was proposed. The Akpek number enables the estimation of VMEs in any possible case. VME is a very crucial obstacle that has urgency to be illuminated by researchers and scientists to improve fluid characteristics. The main goal of this research is to illuminate the importance of this problem and offer a potential solution. The final results are supported by experimental data and numerical simulations using OpenFOAM.

Thermoplastic fracture characteristics of granite suffering thermal shocks

Thermal-shock-dependent thermoplastic fracturing is a prominent characteristic of hydraulic fracturing in high-temperature reservoirs, such as hot-dry-rock geothermal and deep oil–gas reservoirs. When cold water is injected, the rock surrounding the hydraulic fracture tip experiences sudden temperature changes, affecting the cohesive crack's tension-open in the fracture process zone (FPZ), i.e., the temperature-dependent plastic softening behavior. Based on our previously established thermoplastic cohesive fracture model, a description model of rock thermoplastic fracture properties related to thermal shock was proposed. Then, we performed mode-I fracture tests on high-temperature granite subjected to different thermal shock treatments and used digital image correlation (DIC) to characterize the fracture process (especially FPZ development). By comprehensively analyzing loading curves and DIC-based surface deformations, we quantificationally delineated seven thermoplastic fracture characteristics of thermal-shock-treated granite based on the proposed description model. We find that (1) cohesive tensile strength linearly decreases with increased thermal shock. (2) Critical COD and completely developed FPZ length linearly decrease only for temperature differences above 140 °C while they vary slightly for temperature differences from 0 °C to 140 °C (3) Plastic modulus, fracture energy, and accumulated dissipated energy change nonlinearly with the intensification of thermal shock. These three properties slightly vary for temperature differences from 0 °C to 140 °C but significantly reduce once the temperature difference exceeds 140 °C. (4) The temperature sensitivity modulus is mainly positive but follows different evolution laws with the temperature difference (≤140 °C: decreasing; >140 °C: increasing). For temperature differences of 0 °C and 140 °C, the temperature sensitivity modulus shifts from positive to negative only when COD is approximately at 0.5 times the critical value. The positive temperature sensitivity modulus implies that the yield surface of the cohesive crack contracts with enhanced thermal shocks. (5) We compared the linear elastic fracture parameter, energy release rate, with the thermoplastic fracture parameter, fracture energy. Our analysis reveals that the fracture energy is 3.34 ∼ 1.58 times larger than the energy release rate as the thermal shock intensifies, with a significantly different trend in the variability. This highlights the importance of considering thermoplastic fracture characteristics in hydraulic fracturing applications for high-temperature reservoirs. Furthermore, we put forward optimization recommendations based on our findings.

Short-term forecasting of natural gas consumption by determining the statistical distribution of consumption data

The development of gas smart meters has enabled the collection of data on daily natural gas consumption which can be used to develop and improve methods and models for natural gas consumption forecasting. This paper presents the development of a model for the short-term forecasting of total natural gas consumption, which is applicable in different distribution areas where smart meters are installed in large numbers. The advantages of this model are the use of only two input parameters (daily natural gas consumption and average daily temperature), forecasting the total consumption in the determined area by analyzing the consumption data of less than 10% of the total consumers as well as robustness to consumer types. Daily natural gas consumption data collected from the more than 3300 gas smart meters over a period of six months was used for the determination of correlations between lognormal distribution variables and temperature. The defined correlations between distribution variables and temperature were used for upscaling consumption to a specific number of final consumers, i.e., to obtain the total consumption of natural gas in the observed area. Best results were achieved using the “two-day rolling average temperature” in the consumption scenario up to 250 m3 per day (MAPE was 7.26%). When compared to using “average temperature” as an input parameter, “two-day rolling average temperature” and “shaving peaks temperature” produced better results due to the mitigated impact of sudden temperature changes that significantly affected the simulated consumption in the model while the actual consumption is a little more inert. Also, consumption scenarios up to 250 m3 can be considered the most representative for forecasting total natural gas consumption since it achieved the best results.

MPPT Novel Controller Based on Passivity for the PV Solar Panel-Boost Power Converter Combination

This article deals with the MPPT controller based on passivity, which calculates through a dynamic average model between the PV solar panel and the boost power converter under uniform irradiance conditions. The MPPT algorithm is a linear controller based on the exact tracking error dynamics passive output feedback (ETEDPOF) controller design methodology. The algorithm includes suitable adaptive feedforward pre-compensation, which explicitly depends on the precisely estimated resistance of the boost converter. The MPP reaches by regulating the voltage and current of the boost converter to hold the PV maximum power in the system's input capacitor. The controller desired references such as the inductor current, the output voltage, and the average input control are in terms of the PV maximum power nominal values, which remain always fixed. A reduced-order extended state observer (RESO) develops to estimate the boost converter's output resistance, adapting to the controller's desired references. Simulation and experimental results demonstrate the effectiveness, stability, and robustness of the MPPT algorithm based on passivity as compared to the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Incremental Conductance</i> (IC) algorithm, under sudden output resistor changes, high irradiance, and high temperature in the solar panels.

Uncovering the hierarchical clusters in the heat-affected zone of an electron beam welded α/β titanium alloy joint

Using high-resolution transmission Kikuchi diffraction (TKD) and transmission electron microscopy (TEM), we examined the hierarchical clusters that form in situ in the heat-affected zone (HAZ), which are commonly referred to as “ghost” structures, of bimodal titanium alloy Ti-5Al-2Sn-2Zr-4Mo-4Cr (wt%, TC17). The ghost structures are enriched with Al elements but poor in Mo and Cr compared to the surrounding β matrix. TKD results show that the ghost structure in middle-HAZ mainly consists of αL laths with a high-angle grain boundary, which exhibits the classic Burgers orientation relationship (BOR) with the host matrix, while it encircles the αP grains in far-HAZ. And the ghost structure is evidenced to form via incomplete martensitic transformation. TEM results further confirm that the ghost structure is composed of αL and tiny βL laths with BOR, with the former being enriched with Al and poor with Cr and Mo, while the latter is the opposite. Interestingly, two αL variant clusters with a check-mark morphology are frequently observed viewed along [0001]αL//[110]βL directions, which are dominated by the crystallographic and geometrical relationships between α and β phases. Based on the microstructural characterization, it is hypothesized that the ghost structure is transformed from the initial αP phase, due to the coupling effect of high thermal stress (which induces the formation of a large number of dislocations) and element diffusion caused by sudden temperature increase and plunge cooling in the HAZ during the welding process.

Understanding the physical processes in the evolution of a cold air outbreak over China in late November 2022 from a Lagrangian perspective

From 26 November to 1 December 2022, intense cold air masses swept across China from northwest to south, resulting in a nationwide cold air outbreak (CAO) case characterised by drastic and sudden temperature drops with rain, snow and strong winds. The physical processes that dominate the intensification of the cold air masses during this CAO event remain unclear. In this study, the evolution of the CAO case, which is indicated by the dry static energy (DSE), is investigated using a novel approach in the framework of Lagrangian backtracking. The dominant processes can be identified by decomposing the DSE change into four diabatic heating terms due to shortwave radiation, longwave radiation, latent heat and turbulent processes. Overall, in this case, most of the cold air parcels originated from the east of Novaya Zemlya and crossed Central Siberia before reaching China. Thus, these air parcels mainly manifested on the northwest‒southeast path. The duration of the cold air intensification differed between subregions. The cold air parcels experienced long cooling periods (approximately 9 d) before reaching northern China (i.e. Northwest, North and Northeast China), whilst the southern parts (i.e. Central, East and South China) underwent relatively short cooling periods (6–8 d). Accordingly, the cold air affecting northern China is more intense than that affecting the southern parts, especially for East and South China. For all six subregions, longwave radiative cooling is identified as the dominant contributor to the cold air intensification, and the latent heat processes as the secondary contributor. The weakening of cold air parcels as they approach and pass over these regions is driven by turbulent processes and shortwave heating. Central Siberia and Lake Baikal are identified as key areas for the intensification of cold air passing over both regions. In addition, air parcels affecting Northwest China are intensely cooled as they pass over the Junggar Basin, while the North China Plain is a key area for cooling air parcels reaching Central, East and South China. From a Lagrangian perspective, these findings provide insights into the physical processes driving the behaviour of cold air parcels, which would help understand the mechanisms involved in the past changes and future projections in CAOs.