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Abstract During the operation of load cell, heat is generated by the strain gauge and the electronics on the PCB board, which leads to temperature gradients within the sensor itself. These temperature gradients are unstable at different ambient temperatures. Compensation inaccuracies can also occur when compensating for sensor measurements at different temperatures This paper proposes a method to change the position of temperature compensation resistors to address errors caused by the temperature field effect of the strain gauge sensor itself. Without affecting the sensor’s strain measurement, the correctness of the proposed method is demonstrated through steady-state thermal simulation results in ANSYS and experimental results, effectively addressing errors caused by unstable temperature gradients during the operation of strain gauge sensors.

Solar energy is one of the most important and promising energy sectors in the world. Batteries that convert sunlight into electrical energy could become a replacement for traditional carbon-based energy sources. Vertical thin-film solar batteries are one of the new approaches to solar energy generation. The vertical configuration of solar panels provides maximum absorption of sunlight throughout the day. This orientation allows the batteries to capture solar energy even at low angles of incidence of the sun’s rays, which prolongs their operating time and improves the efficiency of electricity production. In this work, the authors proposed a three-dimensional model of a vertically oriented solar battery, as well as they calculated and evaluated the temperature characteristics and the efficiency obtained under conditions of changing ambient temperature. Herewith the power densities of concentrated solar radiation with maximum values from 1 to 10 kW/m2 were varied. The distribution of the maximum values of the surface temperature of the solar battery has been studied. Also, the dependences of the maximum values of the solar battery temperature and the temperature gradient inside it, as well as the dependences of the minimum and maximum values of the heat flux from the solar battery surface on the time of day in the middle of January and July have been studied and plotted. As the calculations have shown, the maximum values of the temperature gradient inside the solar battery in January are ~47–50 % higher than in July. The potential difference, generated by the battery, reaches its maximum values from 11 a.m. to 4 p.m. both in January and July. The use of vertical thin-film solar batteries will improve the power generation efficiency and lower operating costs by reducing the influence of dust, rain and snow.

Direct preparation of glass-ceramics from slag is an efficient way to use the “slag” and “heat” of the slag, making this preparation a sought-after research topic. To prepare glass-ceramics using the Petrurgic method, this paper used silico–manganese slag as the main raw material, along with chromite and serpentine as modifiers. The Petrurgic method is a heat treatment process involving controlled crystallization during slag cooling to form glass-ceramics. The prepared glass-ceramic samples had a diameter of 100 mm and a height of 20 mm. Various tests and analyses such as X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy with energy dispersive X-ray spectroscopy, flexural strength, compressive strength, water absorption, and bulk density were performed on the samples. The influence of different heat treatment regimens on the phase composition and properties of silico–manganese slag microcrystalline glass was discussed. Additionally, the study investigated the temperature variation inside the glass-ceramic samples, and the results indicated that by modifying the slag and annealing it at 700℃ after cooling to the crystallization temperature, microcrystalline glass meets the performance requirements of natural granite. The temperature range of 900–1050 ℃ was found to be associated with the crystallization of the augite phase, while the temperature range of 1000–1050 ℃ was related to the crystallization of the akermanite phase. With improvements in the heat treatment system, the amount of akermanite phase precipitation will increase, and the grain will become coarser than before. At 900 ℃, the grain growth of the microcrystalline glass was not as significant as that of the samples annealed at 1000 ℃ and 1050 ℃, and the lack of excessive crystallization led to fewer defects inside the glass-ceramics. After studying the temperature profile data, it was observed that during the heat treatment process at 1000–1050 ℃, inconsistent crystallization between the inner and outer parts of the sample resulted in a temperature gradient from the center to the edge. After studying the temperature profile data, it was observed that during the heat treatment process at 1000–1050 ℃, inconsistent crystallization between the inner and outer parts of the sample resulted in a temperature gradient from the center to the edge. However, at 900 ℃, the temperatures of the central and edge regions remained consistent during the crystallization stage. For the heat treatment at 800 ℃, the slag temperature quickly decreased below 900–1050 ℃, making crystallization difficult. The overall trend of the temperature difference between the central and side parts of the sample was similar for all four heat-treatment conditions. After casting the slag into the mold, temperature gradients were formed within the sample. These formations do not affect the types of crystalline phases that precipitate; however, they do affect the quantity of crystallization.

In areas with large temperature differences, the uneven distribution of temperatures in the CRTS III ballastless track slab due to daytime sunlight can cause warpage deformation, leading to periodic rail irregularities that increase the wheel-rail impact of high-speed vehicles and accelerate track structure damage. Therefore, it is necessary to study the dynamic contact relationship between the composite slab and the base plate during vehicle running. The results of the study show that: 1) Under the influence of temperature gradients, the composite slab tends to deform elliptically. With a positive temperature gradient, the middle part of the track slab bulges upward, causing the slab to be supported by its four corners. Conversely, with a negative temperature gradient, the four corners of the track slab bulge upward, resulting in the slab being supported by its center. 2) Temperature gradients can lead to separation between the composite slab and the base plate, reducing the contact area between layers. During vehicle running, the contact area between layers gradually increases, but the separation cannot be completely closed. 3) The temperature gradient significantly affects the vertical displacement of the track. The vertical displacement in the middle of the slab increases with a positive temperature gradient. In contrast, the vertical displacement at the ends of the slab increases with a negative temperature gradient. 4) The stress of self-compacting concrete at the side position significantly increases under a positive temperature gradient, with the vertical stress increasing by 2.7 times when the temperature gradient increases from 0 to 90 ℃·m−1.

Purpose – Temperature is an important load for a ballastless track. However, little research has been conducted on the dynamic responses when a train travels on a ballastless track under the temperature gradient. The dynamic responses under different temperature gradients of the slab are theoretically investigated in this work. Design/methodology/approach – Considering the moving train, the temperature gradient of the slab, and the gravity of the slab track, a dynamic model for a high-speed train that runs along the CRTS III slab track on subgrade is developed by a nonlinear coupled way in Abaqus. Findings – The results are as follows: (1) The upward transmission of the periodic deformation of the slab causes periodic track irregularity. (2) Because of the geometric constraint of limiting structures, the maximum bending stresses of the slab occur near the end of the slab under positive temperature gradients, but in the middle of the slab under negative temperature gradients. (3) The periodic deformation of the slab can induce periodic changes in the interlayer stiffness and contact status, leading to a large vibration of the slab. Because of the vibration-reduction capacity of the fastener and the larger mass of the concrete base, the accelerations of both the slab and concrete base are far less than the acceleration of the rail. Originality/value – This study reveals the influence mechanism of temperature gradient-induced periodic deformation in the dynamic responses of the train-track system, and it also provides a guide for the safe service of CRTS III slab track.

In order to study the unstable vibration of generator unit in nuclear power plant, a rotor dynamics analysis model was established, in which the thermal effect induced by oil shear flow in bearing was considered. One-dimensional energy balance equation was used to solve the journal temperature difference caused by the flow of lubricating oil in the bearing small gap. The average journal temperature difference and its angle during a whirling cycle were obtained. The effect of cross-sectional temperature gradient on shaft bending deformation was calculated, and the equivalent bending moment was obtained. The equivalent bending moment was input to the shaft in finite element model, and the bending deformation of the generator shaft was calculated. The results show that the temperature difference of the journal is induced by the shear flow of lubricating oil in the bearing clearance. The temperature difference of the journal increases with the increase of journal eccentricity and bearing clearance. After the eccentricity of the journal increases to a certain extent and the bearing clearance decreases to a certain extent, the temperature difference of the journal section increases rapidly, exhibiting typical nonlinear characteristics. If the amplitude of synchronous whirling orbit increases, the dynamic eccentricity increases and the cross-sectional temperature difference increases. Journal temperature difference of a certain nuclear power generation unit was calculated using the model. Within a reasonable range of bearing parameters in nuclear power units, the temperature difference can reach 10 ℃. Its impact on vibration is equivalent to the impact of G2.5 level imbalance force on the generator. The periodic vibration fluctuation phenomenon that occurred on a certain type of nuclear power unit was introduced. Test shows that the fluctuation amplitude is related to the lubricating oil temperature. It is pointed that the journal temperature difference produces rotational unbalance, resulting in vibration fluctuation. Unstable vibration is related to lubricating oil viscosity, bearing clearance, eccentricity ratio and unbalanced force. The unstable vibration can be reduced by reducing the viscosity of lubricating oil, increasing the bearing clearance, reducing the eccentricity and unbalance. The engineering verification test of adjusting lubricating oil temperature was carried out. The test results show that increasing the temperature of lubricating oil to reduce the temperature viscosity of lubricating oil is helpful to reduce the unstable vibration. The analysis results by calculation are consistent with the engineering practice. The model established in this study can be used for the analysis of unstable vibration of nuclear power generator units.

Sn–Ag solders are widely used for advanced electronic packaging. The combined effect of Ag element and temperature gradient (TG) on the formation of Sn grains in Cu/Sn-xAg/Cu micro solder joints was elucidated systematically. Numerous small-sized β-Sn grains were formed in both Cu/Sn/Cu and Cu/Sn-0.5Ag/Cu micro solder joints after reflow with or without TG. The Cu/Sn-0.5Ag/Cu joint was found to have more twinning β-Sn structures. The formation of the multiple β-Sn grains in these two joints was attributed to the presence of multiple tetrahedral metastable short-range order (SRO) structures which acted as nuclei for the nucleation and growth of β-Sn. The existence of TG slightly enhanced the preferred orientation characteristics of Sn grains. For the joints with Ag content was or higher than 2 wt%, several Sn grains were formed without TG, while a single or highly oriented Sn grains were observed with TG. The number and orientation of Sn grains were affected by the combined effect of Ag element and TG significantly. The β-Sn grains formed without TG were based on the {101} type cyclic twinning configuration clusters that stabilized by Ag atoms and acted as nuclei. The formation of a single or highly preferred β-Sn grains was benefit from the combined effect of Ag element and TG. The results provide theoretical guidance for optimizing the composition of Sn–Ag solders and controlling the microstructure of the joints, thereby contributing to the advancement of electronic packaging technologies.

A two-step joining approach was proposed to minimize or eliminate decomposition bubbles in laser joining metal to polymer. Finite element simulation was utilized to analyze the temperature distribution and incorporated the bubble shrinkage mechanism and thermal capillary effect, providing the theoretical basis for explaining the reduction in bubbles and their movement. Two experimental setups were employed: with and without laser beam offset. In experiments without offset, the bubbles after the second joining process underwent significant shrinkage, resulting in a notable reduction in volume. In offset experiments, the bubbles not only reduced in size but also exhibited movement and elimination. This was induced by the laser beam offset, which created a temperature gradient perpendicular to the joining direction, triggering thermal capillary effects that caused the bubbles to migrate towards the hotter side and eventually escape from the joint edges. Consequently, the joints obtained through double welding exhibited higher fracture stress as compared to those obtained through single welding. The theoretical analysis of the bubble reduction mechanism aligned with experimental observations, further validated by camera images.

The paper is devoted to the study of temperature and stress distribution in the medium-pressure rotor of the K-200-130 turbine, which are of considerable interest when predicting the durability of this equipment and extending its operation beyond the service life. A geometric model of the most loaded part of the rotor – from the middle of the shaft neck in the thrust bearing area to the 5th stage disc – was developed. The study of the thermal and stress-strain state of the rotor during start-up from a cold state was performed in a two-dimensional formulation using the finite element method. The non-stationary problem of heat conduction during start-up was solved. The obtained results indicate a fairly uniform thermal state during variable operating conditions. The largest temperature gradient (1200–2200 K/m) is observed at the time points from the rotor push to the synchronization of the turbine generator with the power system. After the turbine generator is loaded with up to 30 MW of electric power, a decrease in the temperature field irregularity and its gradual stabilization are observed. It was found that when operating at the nominal steam parameters, the maximum metal temperature is 508 °C in the region of the control stage and decreases when the distance from it increases. The stress-strain state of the rotor was evaluated taking into account the unevenness of temperature fields during start-up, stresses from thermal expansion, and centrifugal forces. The highest stresses are characteristic of the moment when the turbine comes to idle in the area of thermal compensation grooves of the rotor and the control gate and amount to 440–472 MPa. It is noted that these areas are the most likely zones of ring crack nucleation during turbine start-up operations. Subsequently, the stress level gradually decreases as the turbine unit reaches its rated power. It has been established that the most stressed area of the rotor during stationary operation is the area of the axial bore under the control stage and its diaphragm seal (121–134 MPa)

This study aimed to elucidate the influence of various culture medium components, including carbon sources, nitrogen sources, inorganic salts, suspension agents, and temperature, on the mycelial growth characteristics of Phallus dongsun. Employing single-factor experiments and response surface methodology within glass Petri dishes, the research identified that carrot powder, soybean powder, and ZnSO4 notably enhanced the proliferation of aerial mycelium, significantly augmenting the growth rate of P. dongsun mycelium. The resultant mycelium was observed to be dense, robust, and fluffy in texture. In particular, ZnSO4 markedly accelerated the mycelium growth rate. Furthermore, xanthan gum was found to effectively modulate the medium’s viscosity, ensuring a stable suspension and facilitating nutrient equilibrium. The optimal cultivation temperature was determined to be 25°C, with mycelial growth ceasing below 5°C and mycelium perishing at temperatures exceeding 35°C. The optimal medium composition was established as follows: wheat starch 5 g/l, carrot powder 5 g/l, soybean powder 7.50 g/l, glucose 10 g/l, ZnSO4 0.71 g/l, NH4Cl 0.68 g/l, xanthan gum 0.5 g/l, and agar 20 g/l. Under these optimized conditions, the mycelium of P. dongsun exhibited a rapid growth rate (1.04 ± 0.14 mm/day), characterized by a thick, dense, and well-developed structure. This investigation provides a theoretical foundation for the conservation, strain selection, and breeding of P. dongsun.

The temperature dependences of the thermoelectromotive force of chromium mono and disilicides in the temperature range 200℃÷+600℃ have been studied. For chromium disilicide, the dependence of the thermopower coefficient (α) on temperature (T) has three sections. Chromium monosilicide is characterized by a smooth increase in thermopower with increasing temperatures up to 200℃, and then its constancy. It was revealed that silicides rich in chromium atoms have lower thermopower values than silicides rich in silicon. The maximum thermo-EMF values of 110 μV/K and 190 μV/K were observed for chromium mono- and disilicides, respectively. It was revealed that for chromium silicides the dependence of the dimensionless parameter Q = Z∙T on temperature is linear. The possibility of predicting the technology of synthesis of semiconductor material with optimal thermoelectric properties using the dependence of thermopower on conductivity and the parameter Q on temperature is shown.

The initiation of the first crack mainly determines the criteria for glass failure. However, the extended consequences of cracking, with the formation of multiple cracks merging, result in fallout conditions under varying thermal loads that become more critical. Point-supported glass arrangements are globally used in high-rise and energy-efficient buildings for architectural ingenuity aimed at a low budget. However, the formation of cracks due to thermal load resulting in glass breakage could infuriate the overall fire dynamics of the enclosed area. Therefore, experimental study and prediction of glass failure become very crucial. The present experimental study focuses on finding the most critical parameter that may quantify the cause of glass failure and further breakage in fallout conditions under varying thermal loads. 45 experiments were carried out on float glass of 300 × 300 mm2 with 4 mm, 6 mm, 8 mm, 10 mm, and 12 mm with continuous fuel supply arrangements. Critical parameters analysed were the time of crack initiation, glass temperature at the time of cracking, maximum temperature difference at glass failure, and thermal strain caused by the temperature difference on the glass surface. The range of minimum and maximum temperature difference recorded on the glass surface for the present study was between 30–35°C and 55–60°C at the breakage time for all the experiments. The Maximum temperature difference measured was 56.99°C on the 12 mm glass surface, and the corresponding maximum thermal strain found was 482 × 10−6 mm/mm. The maximum heat release rate was found to be approximately 200 kW. Maximum heat flux was found in the range of 10.33 kW/m2 to 21.14 kW/m2. A correlation was also developed using the least square method for all the thicknesses, which is well correlated with the glass thickness per unit length.

A thorough understanding of the reactor core thermal hydraulic behavior is essential for the design and safety analysis of Sodium-cooled Fast Reactors (SFR). Due to the application of hexagonal subassembly, the core thermal hydraulic behavior is significantly affected by the flow field within the subassemblies, the inter-wrapper region and the hot pool. Analysis of the core thermal hydraulic behavior requires a model coupling the three regions mentioned above, which has been identified as one of the thermal hydraulic challenges in SFR. In the present study, a 3D model that covers the three regions was developed for the core of the China Experimental Fast Reactor (CEFR) with the Computational Fluid Dynamic (CFD) code, Fluent. The inter-wrapper region and the hot pool were modeled in detail, while the subassemblies were modeled with a special porous medium model. The core thermal hydraulics behavior under steady state was studied, more specifically, information for the flow field distribution at the core outlet, the inter-wrapper flow and the duct wall temperature distribution was obtained. Under steady state, liquid sodium in the inter-wrapper region is supplied by the inner region of the hot pool. And it enters the inter-wrapper region from the core outer region and returns back to the hot pool inner region from the core central region. The inter-wrapper flow is cooled by non-fuel subassemblies and heated up by fuel subassemblies. For non-fuel subassembly, the ratio of the total heat transfer rate between the inter-wrapper flow and the subassemblies to the heat generated within subassemblies could reaches 96%; for fuel subassemblies, the maximum ratio of the total heat transfer rate between the inter-wrapper flow and the subassemblies to the heat generated within subassemblies is 2.45%. Significant temperature gradients have been observed on the duct wall, with maximum values of 156.69 K/m in the vertical direction and 2,196.00 K/m in the circumferential direction. The largest temperature gradient appears on the duct of subassemblies adjacent to the transition region of fuel subassemblies and non-fuel subassemblies.

The use of polymers for water storage or distribution is closely monitored, especially with regard to the possible contamination with substances coming from the material's surfaces. Different standards are practiced across countries according to type of applied materials and such test methods are prevalently based on constant temperature conditions. However, these polymers systems could be located in diverse environment which does not necessarily provide constant conditions. Experimental findings show that exposure of liquid inside polymeric materials to specific temperature gradients, and consequently to emerging organized flows, can result in an accelerated leaching of undesirable substances from the solid surface. In presented work model steady-state and organized flow conditions are used to compare release of contaminates from polyethylene by measuring of surface tension, UV–Vis spectroscopy, FTIR, scanning electron microscopy and elemental analysis of polymer surfaces and water leachates. The pilot study shows that convective flow generated via temperature gradient significantly affects contaminant release in comparison to a steady state and mixing flow conditions.

To further study adiabatic parameters distortion, the adiabatic decomposition of 2,4-DNT, 20%DTBP, and 45%Glucose was systematically analyzed using thermal analysis calorimetry and numerical simulation methods. The study revealed the variation laws and influence mechanisms of the temperature gradient effects and thermal inertia in adiabatic systems. A numerical model for decomposition in a closed adiabatic system was developed by integrating the apparent kinetics into the CFD code. The results show that the temperature gradient effects during adiabatic decomposition initially increase and then decrease until reaching zero. The temperature gradient effects become more pronounced as the exothermic characteristics of substances increase. They are the most significant at the peak self-heating rate, with gradients of 182.4 °C·cm−1, 21.6 °C·cm−1, and 0.78 °C·cm−1, respectively. Specific data segments for adiabatic analysis should maintain α values below 0.138 for 2,4-DNT, 0.484 for 20%DTBP, and should utilize complete 100 % adiabatic data for 45%Glucose, aiming to mitigate potential distortion in adiabatic parameters. Furthermore, Фeff varies with the reaction, initially increasing and then decreasing in deviation from the theoretical value, with peak deviations of 60 %, 20 %, and 0.3 % for three substances, respectively. These findings lay the foundation for further optimizing the temperature gradient effects and establishing a dynamic Фeff correction model.

Combination steam ovens, or combi steamers, have entered all spheres of food production, including the meat industry. Their rational use requires a scientific and practical foundation. This research featured the changes in mean volume temperature and temperature gradient that occur in meat products (one-dimensional bodies with different nutrient compositions) during heat treatment in dry air and a steam-air mix. The research involved two samples of meat products with different moisture and fat contents. The chicken fillet sample had a moisture content of 74.5% and a fat content of 1.9% while the pork shoulder sample had a moisture content of 55.1% and a fat content of 29.4%. Shaped as a one-dimensional cylinder and a plate, the samples were subjected to heating at the temperature range of 160–240°C in a Unox-203G steam-convection oven (Italy). Dry air and a steam-air mix with a humidity of 80–85% served as a heating medium. The temperature was measured using thermocouples attached to a Sosna-004 meter. The research revealed some patterns in the mean volume temperature and temperature gradient. The temperature gradient involved three stages during processing in a steam-air mix and four stages when treated with dry air. The change in the mean volume temperature for the steam-air mix could be described by a power law equation; the dry air treatment was described using a linear equation. When heated in dry air, the rate of change in the temperature gradient was constant at first but started to decrease at a certain stage. The change rate in the mean volume temperature remained low for 5 min and started to increase onwards, maintaining its value until the end of the process. When heated in a steam-air mix, the change rate in the temperature gradient dropped to its minimum in 4–5 min and started to grow. The mean volume temperature demonstrated a high change rate during the first 5 min and went down. The chicken fillet with its low fat content warmed up faster by 13–26% when processed in a steam-air mix and by 9–23% when treated in dry air. The plate-shaped products needed longer heat treatment. The composition and form had no significant effect on the nature of the change in the temperature gradient and mean volume temperature. The obtained dependencies made it possible to select the optimal temperature and humidity conditions for convective frying of meat products.

The paper studies effect of induced magnetic field on laminar convection flow of a viscous electrically conducting incompressible fluid between two parallel porous plates at constant temperature gradient in presence of a uniform inclined magnetic field. An angle (θ) is formed with the vertical line by applying a magnetic field in that direction and field is strong enough to induce another field along the line of flow. Using the proper similarity transformations, the flow equations are converted into ordinary differential equations, which are then numerically solved by using MATLAB's bvp4c solver. Plotting of the graphs allows one to examine the effects of several critical parameters such as Hartmann number, Darcy number, Magnetic Reynolds number, Prandtl number, and Field inclination on velocity field, induced magnetic field, temperature field at the plates. The acquired results demonstrate that the flow system is effectively influenced by the field inclination, the magnetic parameter, and the plate porosity. The rise in field inclination leads to an increase in magnetic drag force.

Exposure to fire can deteriorate steel-to-concrete bond, which is essential for structural integrity of reinforced concrete members. Prediction of the performance under fire is essential for design, while estimating the post-fire bond is paramount for assessing damaged structures. Existing research focused on the performance of a single rebar. Study reported herein deals with experimental and numerical investigation of post-fire bond behaviour of members with twin rebars. Experimental results are used to validate the numerical approach, which is subsequently used to extend the experimentally tested range of fire duration. Severe impact of fire on bond is observed, regardless of the concrete cover, rebar spacing and fire duration. A reduction in bond capacity is observed for twin rebars compared to single rebar for all the investigated cases.

This study is part of a comprehensive research effort focused on examining the impact of various parameters on the post-fire bond behaviour of RC flexural members. Precisely, the impact of the rebar diameter is thoroughly discussed. Beam-end specimens, which realistically simulate the boundary conditions of a full-scale beam while maintaining a relatively compact size, were subjected to ISO 834 fire curve. To investigate the behaviour of lap-splice in a slab and beam, two different fire exposure scenarios, where one side (slab) and three sides (beam) of the specimens were exposed to fire, were considered. It is evident that although the initial and residual load-carrying capacities increase with larger rebar diameters in absolute terms, the differences in residual bond capacities remain relatively insignificant across nearly all examined fire-exposure durations. Based on the evaluation of the test results, a model for local bond stress-slip curve of bond affected by fire is proposed.

The solar temperature field of steel-concrete composite girder bridges has a significant impact on structural stress. To evaluate the distribution of solar temperatures, this paper conducted analyses of the solar temperature field of the Xuefeng Lake Bridge through on-site measurements and numerical simulations. The study investigated the temperature field characteristics of the composite girders according to the temperature data. Based on the numerical simulation results, a finite element computational model for the vertical temperature gradient of the steel-concrete composite girder bridge was established, and the maximum gradient temperature values of the composite girders were calculated by using the 24-year historical data from 2000 to 2023. The extreme value parameters related to the GEV distribution model were determined. Taking into account the correlation between the annual maximum environmental temperature and wind speed, a joint distribution model was established using Copula functions. The results indicate that the average error of the numerical model is within 5 %. The wind-temperature joint distribution model, considering the effects of wind speed, tends to provide more conservative results. The calculated extreme values of temperature gradient load show an expanding trend, with the exceedance probabilities for recurrence periods of 100 years, 50 years, 20 years, 10 years, and 5 years being 0.64 %, 1.34 %, 2.29 %, 3.51 %, and 7.32 %, respectively.

Abstract There is a global need for clean and renewable energy sources. This study investigated thermoelectric generators (TEGs) as a possible method for harvesting solar power. The TEG prototype tested here consisted of two equally sized pieces of roof sheeting, with one side exposed to a light source and the other side shaded. Experiments were carried out with the necessary testing components to investigate the effects that two variables have on the amount of power generated: first, the colour of metal inverted box rib (IBR) sheeting and, second, the ideal electrical arrangement for scalability of Peltier tiles for maximum power output. Black-coated sheets generated maximum power (Pmax) output of the TEGs. The TEGs in series configuration generated the highest Pmax when located closest to the light source. The conclusion from the experiment is that TEGs are a potential method of harvesting solar energy on IBR sheeting, specifically in a vertical position. However, applications of different orientations and geographical locations require further investigation, including into the use of TEGs on IBR sheeting for harvesting solar energy on a larger scale.

Massive high-strength concrete generates significant hydration heat during casting, which indirectly influences the risk of structural cracking by affecting the internal temperature gradient distribution. This paper investigated the effect of layered pouring methods on internal temperature gradients in massive concrete using the precast bent caps of a Shanghai bridge project as a case study. The temperature-time development patterns of each poured layer were studied through three sets of physical experiments. Temperature gradient distribution functions were established to specify the spatial temperature distribution trends of each layer. The interconnectedness between the spatial temperature distributions of adjacent poured layers was explored based on the established distribution functions. Targeted anticracking suggestions for layered poured concrete were provided based on these correlations. Additionally, a novel temperature control measure for managing hydration heat was proposed. The feasibility of this measure was verified through practical experiments. Moreover, corresponding finite element models were established to investigate the influence of parameters such as structural lead, outer wall pipe radius, and cooling water flow rate on the internal temperature field of concrete. The hydration heat-time patterns of the poured layers all showed a skewed single-peak distribution. The hydration heat of odd- and even-numbered layers exhibited different Gaussian distribution patterns in the lateral direction; the correlation between the spatial temperature distributions of adjacent layers could be quantified by the ratio of the standardized variance of the Gaussian distribution function of temperature for each corresponding layer. Implementing temperature control measures at specific reasonable positions and using a natural logarithmic function to calculate the design limits of structural dimensions could effectively prevent structural cracking. The newly proposed hydration heat control measure improved the temperature gradient distribution within the concrete. Reducing the structural lead, increasing the outer wall pipe radius, and increasing the cooling water flow rate all resulted in a decrease in the peak temperature inside the concrete. Finally, a structural lead of 0.4 was recommended for actual construction projects, for which the outer wall pipe radius should not exceed 30 mm.

The bentonite material is currently used in a variety of applications ranging from hydraulic barriers and waste-buffer protection to other special uses in industry and underground disposal of high-level nuclear waste. In the deep geological repository for high-level radioactive waste, the clay acting as a buffer material between the host rock and the canister is subjected to thermal load, which could impact its geotechnical properties. Thus this study is aimed at investigating the swell and compressibility of bentonite subjected to heating at 200 °C, 400 °C, and 600 °C. The impact of heating on the index properties, the swell and compression and hydraulic conductivity is explored. The change in temperature due to weather fluctuations was found to have a minor effect on physical behavior, but this effect is found to be significant when the temperature is raised to high levels in the order of 200 °C–600 °C (Celsius). The rate at which swell and hydraulic conductivity is developed is presented in this study. The result indicated an elimination of the swellable clay minerals effect in the bentonite clay upon exposure to a temperature of 600 °C. This study introduces useful information and data for modeling the behavior of bentonite when subjected to elevated temperatures for use in application for deep geological repository for high-level radioactive waste storage and other applications.

Preheating is important to improve the mechanical properties of nickel-based superalloys processed by additive manufacturing. The microstructure of IN718 was found to be influenced by the preheating temperature. Different preheating temperatures affect mechanical properties by changing microstructures. This work aims to clarify the thermal behavior for two preheated base plate temperatures (200 °C and 600 °C) on the IN718 superalloy built by the selective laser melting (SLM) process using the finite element method and experiments. The simulation findings indicate that the preheated 600 °C model has a deeper melt pool, a slower transformation of liquid to solid, and a slower cooling rate compared to the 200 °C model. As a result, the interdendritic Niobium (Nb) segregation of IN718 is reduced, thus improving the mechanical properties of additive-manufactured IN718 using the laser. The solidification map derived from the simulation indicates a columnar microstructure for the IN718 superalloy. Preheating increased the size of the dendrite structure and reduced elemental segregation, but it did not affect the morphology or size of crystal grains. We focused on comparing the temperature gradient and cooling rate for the two preheated base plate temperatures using the solidification map of IN718. The simulation confirmed that preheating does not affect the grain structure.

Within the theory of thermo-elasticity, the temperature field of thin plates is commonly defined via two parameters: temperature in the mid-plane and linear temperature gradient normal to the mid-plane. First, the paper analytically proves the justification of that assumption in machine structures. Then, in an analytical closed form, applying the integral transformation method, the thin plate deflection caused by a constant temperature gradient is defined. It is shown that, in that case, the plate deflection does not depend on its thickness but only on the plate dimensions in the mid-plane. Analytically defined values are compared to corresponding values obtained by applying the thin plate finite element, where the temperature field is described using the two mentioned parameters. This finite element is defined and programmed within the Komips program package. The influence of the temperature gradient on the behavior of constructions mostly depends on the type of material. That is why the behavior of some structural elements made of brass, steel, and concrete is analyzed in this paper.

Due to the large daily temperature difference on the ultra-high altitude plateau of China, the actual vertical temperature gradient (TG) of ballastless track may exceed the design value in the Code. The temperature monitoring platform of the double-block ballastless track was established to obtain the temperature distribution characteristics of track. The finite element model of the temperature field of the track is developed to study the warping deformation of track, and then the influence of TG on the dynamic responses of the vehicle-track-bridge system (VTBS) are investigated. The results show that the maximum positive temperature gradient (PTG) and negative temperature gradient (NTG) of the track bed slab are 88.875 ℃/m and − 47.159 ℃/m, respectively, and the latter exceeds the design value in the Code. The dynamic responses are positively correlated with the TG, and the influence of the NTG is more significant. The dynamic response of the rail is most sensitive to the TG.

Directed energy deposition with laser beam (DED-LB) components experience significant residual stress due to rapid heating and cooling cycles. Excessive residual tensile stress can lead to cracking in the deposited sample, resulting in service failure. This study utilized digital image correlation (DIC) and thermal imaging to observe the in situ temporal evolution of strain and temperature gradients across all layers of a deposited 316 L stainless steel thin wall during DED-LB. Both continuous-wave (CW) and pulsed-wave (PW) laser modes were employed. Additionally, the characteristics of thermal cracks and geometric dislocation density were examined. The results reveal that PW mode generates a lower temperature gradient, which in turn reduces thermal strain. In CW mode, the temperature–stress relationship curve of the additive manufacturing sample enters the “brittleness temperature zone”, leading to the formation of numerous hot cracks. In contrast, PW mode samples are almost free of cracks, as the metal avoids crack-sensitive regions during solidification, thereby minimizing hot crack formation. Overall, these factors collectively contribute to reduced residual stress and improved mechanical properties through the adjustment of pulsed-wave laser deposition.

The traditional passive heat dissipation method has low heat dissipation efficiency, which is not suitable for the heat dissipation of the concentrated heat source inside the long-focal aerial camera, resulting in temperature level changes and temperature gradients in the optical system near the heat source, which seriously affect the imaging performance of the aerial camera. To solve this problem, an active heat dissipation method of liquid cooling cycle is proposed in this paper. To improve the solving efficiency and ensure simulation accuracy, a dynamic boundary information transfer method based on grid area weighting is proposed. The thermal simulation results show that the liquid cooling method reduces the heat source temperature by 70.12%, and the boundary temperature transfer error is 0.015%. The accuracy of thermal simulation is verified by thermal test, and the simulation error is less than 6.44%. In addition, the performance of the optical system is further analyzed, and the results show that the MTF of the optical system is increased from 0.077 to 0.194 under the proposed active liquid cooling cycle heat dissipation method.

The high-temperature and high-humidity conditions arising from the biochemical degradation of landfill waste result in significant temperature gradients within the landfill cover. The effects of waste temperature on landfill gas transport and microbial aerobic methane oxidation are not fully understood. In this study, a fully coupled theoretical model was developed to simulate the interactions of moisture, heat, and gas transport within a capillary barrier cover. A series of parametric studies were carried out to investigate the influence of the combined effects of temperature gradient, initial soil moisture content, and landfill gas generation rate on methane transport, oxidation, and emissions. The simulated results indicated that increasing waste temperature intensified the temperature gradient, leading to higher surface evaporation rates and variations in methane oxidation efficiencies. Additionally, variations in initial soil moisture content and landfill gas generation rates were found to significantly impact gas migration and methane oxidation in the cover. This study demonstrates the critical role of waste temperature in landfill gas migration within landfill cover systems, providing technical methodologies for the optimized design of soil cover systems.

As the water pipe cooling system is widely applied to controlling temperature in mass concrete structures, the precise simulation of the temperature field in mass concrete with cooling pipes embedded is meaningful. This paper presents an isogeometric analysis (IGA) with NURBS for heat transfer in mass concrete with consideration of the cooling pipe. The proposed method not only achieves the same level of accuracy with fewer nodes but also eliminates the time-consuming process of mesh in the traditional FEM. The coarsest parameter space which depicts small pipe and large concrete precisely is constructed to create an efficient model for numerical computation. In addition, the unique k-refinement in IGA is supposed to be the most appropriate encryption mechanism, and the knot insertion vector for effective refinement is calculated by considering the characteristics of temperature gradient distribution around the cooling pipes. In addition, a different calculation parameter has been discussed to show the stability and flexibility of the IGA. The obtained numerical results demonstrate the accuracy and efficiency of the proposed scheme in the simulation of transient temperature fields in concrete structures with cooling systems.

Soil properties play a crucial role in the stability of engineering foundations, particularly in cold regions where temperature gradients impact water migration and soil conditions. This study utilized MRI-Cryogenic Soil-Moisture Analyzer (MRI-CSMA) to conduct indoor freeze-thaw experiments on silty clay specimens with varying initial water contents (12.0 %, 16.8 %, and 21.1 %). Dynamic changes in water content and temperature at different soil depths were analyzed. The results revealed distinct stage decrease characteristics in both temperature and water content as freezing progressed, with more pronounced changes closer to the cold end. Conversely, during thawing, temperatures and water content gradually increased as the boundary temperature rose. Notably, after the freeze-thaw cycle, the frozen zone consistently retained higher water content than the unfrozen zone, indicating water redistribution, regardless of initial water content levels. Furthermore, in three soil samples with different initial water contents, the water migration flux in the unfrozen soil layer decreased exponentially as freezing time increased. This phenomenon can be attributed to the combined effects of water boundary conditions, temperature gradients, and soil structure changes during soil freezing. These findings are likely to have significant implications for understanding water-heat dynamics in cold region soils as well as ensuring the stability of engineering projects.

This work seeks to present an investigation about the trajectories followed by rays of light passing through refractive index gradients that was entirely carried by high school students. Such trajectories are curved, therefore contradicting the common sense that light should always travel along straight lines. This fact causes the formation of distorted and striated images, similarly to a type of mirage known as Fata Morgana. Using a rectangular aquarium containing solutions with different gradients of sugar or water with a temperature gradient, we analyzed the conditions for image inversion to occur. Also, we were able to reconstruct a distorted image through our theoretical predictions.

IntroductionClimate change affects the vitality of mountain forests through increasing temperatures and decreasing water availability due to changing precipitation patterns, earlier snowmelt, and increasing evaporative demand. Depending on species characteristics, tree growth might therefore increase in cold habitats near the forest line but decrease in water-limited conditions at low elevation.MethodsWe analyzed the tree-ring widths of five conifers (Picea abies, Larix decidua, Pinus sylvestris, Pinus nigra, and Pinus cembra) along an elevational gradient from 1,000 m to 2,320 m above sea level (a.s.l.) in Vinschgau/Val Venosta Valley in Northern Italy, one of the driest regions of the Alps (mean annual precipitation of 682 mm at 1,310 m a.s.l.).ResultsOur aim was to estimate the species-specific growth response to changing climate conditions along an elevational gradient. At low elevations, we observed a significant response to water availability not only during the actual growing season but also throughout the previous autumn for all species present. At mid-elevation, the correlation coefficients to precipitation and drought indices (SPEI) were highest for Picea abies. At high elevations, the positive correlation of growth with temperature was smaller than expected for Pinus cembra. In contrast, Larix decidua responded positively to temperature and grew faster in recent decades.DiscussionConsidering that a further increase in temperatures will reduce plant water availability during the growing season, our space-for-time approach provides an outlook on future growth conditions of conifers in larger regions of the European Alps. Water limitation will affect tree growth and vitality not only at low elevation in the valleys but also at mid elevation on mountain slopes, potentially impacting timber production and protective and recreative functions of forests. Near the forest line, the different capabilities of tree species to benefit from higher temperatures might lead to changes in species composition.

This mini review discusses the phenomenon of thermophoresis, also known as the thermophoretic effect. Thermophoretic effect arises from the combination of a temperature gradient and particles of very small dimensions, on the order of magnitude of the mean free path of the molecules of the surrounding gas. Despite being a little-known effect, it is critical to many physical and chemical processes and for characterising the properties of nanostructured materials that could be used in industry for sensing applications. A description and definition of otherwise very similar thermophoresis terms is provided, as well as a brief overview of the literature on this topic, with a focus on research in the twenty-first century.

This study investigates the feasibility of utilizing the finite element method (FEM)-based conductive heat transfer (CHT) analysis simulation to determine temperature gradients and solidification rates at the solid–liquid interface during laser beam oscillation welding. By comparing experimental observations with FEM-based CHT analysis, the underlying microstructural evolution and grain formation during welding were examined. FEM-based CHT enables the calculation of temperature gradients (G) and solidification rates (R), offering insights into the formation of equiaxed structures, which are crucial for suppressing hot cracking. Columnar-to-equiaxed structure transition thresholds, such as G/R and G3/R, accurately predict the emergence of fully equiaxed grain structures, validated by electron backscatter diffraction. This research provides valuable insights into temperature gradients and solidification rates in oscillation welding, guiding process design for achieving refined equiaxed structures and minimizing hot cracks.

Direct-current gas-insulated switchgear (DC GIS) is an important device for promoting the lightweight and compact design of offshore wind power platforms. Gas pressure and temperature gradients are crucial factors that must be considered during the design process of the DC GIS. In this study, the multi-physics coupling model of basin insulators considering surface charge accumulation was established, and the corresponding real-sized insulator surface charge measurement platform was constructed. The effects of gas pressure and temperature gradient on the surface charge accumulation characteristics were investigated, respectively. The results show that the effect of gas pressure on the surface charge distribution characteristics depends on the dominant mode of surface charge. When volume conduction is dominant, the effect of gas pressure on the surface charge is negligible. However, when gas conduction is dominant, the accumulation of a uniform charge pattern on the insulator surface increases with the rise in gas pressure. Furthermore, due to gas convection, the temperature of the upper part of the DC GIS is significantly higher than that of the lower part, which leads to a temperature difference between the upper and lower surfaces of the insulator. The charge density on the insulator upper surface near the central conductor rises with the increase in load current.

To investigate the effects of differential temperature on microstructure, interfacial morphology and mechanical properties of Mg/Al composite plates, asymmetric rolling was used to prepare Mg/Al composite plates. The results show that the shear deformation induced slip system at interface is less and the degree of dislocation accumulation is higher in isothermal rolling compared to differential temperature rolling. This results in a higher degree of subgrain in each layer and higher tensile and yield strength of composite plate. However, the plate is prone to stress concentration at interface, which severely reduces elongation and bond strength. The differential temperature rolling can better promote the recrystallization of magnesium alloy and grain refinement of aluminum alloy at interface by introducing temperature gradient. This reduces the occurrence of stress concentrations at interface, resulting in higher elongation and bond strength of composite plate.

In order to investigate the distribution of temperature field in directionally solidified DZ4125 columnar superalloy, and to study the effects of different withdrawl rates on the changes of temperature gradient and mushy zone, the directional solidification processes with withdrawal rates of 3, 5 and 7 mm/min were simulated by ProCAST software. The results show that when the test rod is located in the heating zone, the isotherm is inclined distribution with low outside and high inside. And when the test rod is located in the cooling zone, the isotherm is inclined distribution with high outside and low inside. With the increase of withdrawal rate, the temperature gradient decreases gradually. The shape of the mushy zone depends on the withdrawal rate and the distance from the water-cooled plate. When the withdrawl rate is 5 mm/min, the horizontal state of the solidification front is maintained for a longest time. On this basis, the precision casting experiment of directional solidification test rod is carried out, and the relationship between the shape of liquidus and grain structure is found for castings withdrawn at 3 and 7 mm/min. It is found that when the liquidus is concave and convex, the grain grows towards the center and the surface of the test rod, and the horizontal liquidus can promote the grain growth along the axis of the test rod.

The development of modern diagnostic medicine, the important task of which is the use of non-invasive methods for detecting a disease without impact of radiation exposure, has led to the spread of the method of infrared thermography, which allows to quickly and informatively identify pathological conditions of a person within a single examination. The main complaints characteristic of Raynaud's phenomenon are associated with cold, hyperemia, edema, and a feeling of paresthesia in the limbs. A significant number of scientific works have been devoted to the study of the Raynaud's phenomenon, where basically, examples of manifestations of Raynaud's phenomenon are given in the form of a violation of the microcirculation of the distal parts of limbs. Comprehensive studies of the combination of Raynaud's phenomenon with concomitant diseases, according to the authors, are insufficiently covered. The application of sophisticated modern laboratory diagnostic methods to detect this disease is nonspecific and burdensome for the patient. Thermographic diagnostics within one examination reveals both the presence of signs of Raynaud's phenomenon and concomitant somatic diseases. This paper presents the results of many years’ thermographic research, demonstrating the variety of manifestations of the Raynaud's phenomenon. For the first time, it has been shown that patients with signs of Raynaud's phenomenon, as a rule, have concomitant somatic diseases, which should be the subject of research of specialists in different medical fields to determine the relationship of Raynaud's phenomenon with the identified diseases. The results of visualization of thermoasymmetries of the skin of various pathological conditions during a complex thermographic examination were obtained, which greatly simplify the diagnostic search and understanding the complexity and danger of Raynaud's phenomenon. Of particular importance are the results of work for the differential diagnosis of complications of diabetes mellitus – diabetic foot syndrome. The paper presents some results of thermographic examinations of patients with signs of Raynaud's phenomenon and identified pathological changes in the body.

Abstract The micro-electromechanical system (MEMS) infrared thermopile is the core working device of modern information detection systems such as spectrometers, gas sensors, and remote temperature sensors. We presented two different structures of MEMS infrared thermopiles based on suspended film structures. They both deposited silicon nitride over the entire surface as a passivated absorber layer in place of a separate absorber zone, and the thermocouple strip was oriented in the same direction as the temperature gradient. The same MEMS preparation process was used and finally two different structures of the thermopile were characterized separately for testing to verify the impact of our design on the detector. The test results show that the circular and double-ended symmetrical thermopile detectors have responsivities of 27.932 V/W and 23.205 V/W, specific detectivities of 12.1×107 cm·Hz1/2·W−1 and 10.1×107 cm·Hz1/2·W−1, and response time of 26.2 ms and 27.06 ms, respectively. In addition, rectangular double-ended symmetric thermopile has a larger field of view than a circular thermopile detector, but is not as mechanically stable as a circular thermopile.

Water vapor adsorption on soil, a crucial non-rainfall water resource in arid regions, warrants further experimental investigation, particularly on two typical land surfaces: bare soil and gravel. This study examined the formation characteristics and influencing factors of vapor adsorption in an arid region of Northwestern China. Observations and analyses were conducted on adsorption and evaporation measurements taken by two small weighing lysimeters (SLSs); soil temperature at a depth of 5 cm; surface temperature; relative humidity; and air temperature at a height of 30 cm above the ground from 2019 to 2020. The adsorbed water in this area was more abundant at night and less abundant during the day, with a stable nightly adsorption rate of 0.013 mm/h. Adsorption was more frequent in spring and winter (from January to June and November to December), accounting for about 90% of the total annual adsorption. In 2019 and 2020, the ratio values of adsorption to evaporation were 0.16 and 0.10 for bare soil, and 0.10 and 0.12 for gravel, respectively. Adsorption was more likely to occur when the soil moisture content was less than 13%; the highest adsorption frequency was close to 20% when the RH was between 75 and 95%; low soil temperatures were more conducive to the occurrence of adsorption. The effect of temperature differences (Ta−Ts) on adsorption was stronger than that of relative humidity. The adsorption frequency generally showed a bimodal change with increasing temperature difference, but the effect of temperature differences was less effective for gravel than bare soil. When the relative humidity was high and the temperature difference was weakly positive, the maximum adsorption intensity could reach 0.18 mm/h.

ABSTRACTRecently, the triboelectric nanogenerator (TENG) has been widely studied for the development of flexible and wearable electronics. Among the various methods for TENG modification, melting near-field direct writing is a new method to fabricate solid-liquid TENG. Here, the electrospun PCL was introduced with traditional polymers to fabricate the compound solid triboelectric layer, and water, dimethicone and GaIn were chosen as the liquid triboelectric layers. In this paper, the solid substrate effect, temperature gradient effect, and the liquid substrate effect were compared in terms of TENGs. A free-standing model of TENG is employed in this paper, and the charge generated by the PCL-PI composite solid triboelectrical solid layer is more than 10 times higher than the pristine one, showing the high charge generating ability to melt near-field direct written microfibers. Furthermore, detailed investigation will be discussed how we can get a high the out-circuit voltage and short-circuit current.

Large-scale ocean‒atmosphere circulations (LOACs) have a pronounced effect on the near-surface wind speed (NSWS). In this study, we discussed the contributions of zonal and meridional flows to NSWS changes and identify the possible association between the Northern Hemisphere Annular Mode (NAM) and the NSWS changes over eastern China from 1979 to 2017. Results show that the reduction in NSWS over eastern China was mainly dominated by the weakening of the zonal wind component. NAM has a considerable effect on the NSWS over eastern China. When the NAM exhibits positive phases, the zonal-mean westerly weakens at low-to-mid-latitudes (10°–40°N). Meanwhile, descending flows prevail near 40°N, and ascending flows persist near 65°N in the troposphere. In the lower troposphere, there are northerly anomalies at low-to-mid-latitudes and southerly anomalies at mid-to-high latitudes (40°–70°N). The anomalous meridional flows transport heat from low to high latitudes and weaken the north‒south air temperature gradient. The decreased air temperature gradient over East Asia reduces the pressure gradient near the surface, decreasing NSWS in eastern China. NAM variations could dominate (32.0 ± 15.8)% of the changes in the annual mean NSWS. Nevertheless, the contribution of NAM to the interannual changes of the zonal component in NSWS could reach (45.0 ± 12.9)%.

A theoretical model is developed to investigate the density gradient driven instability in an [Formula: see text] plasma system with the consideration of finite temperature of both the electrons and the ions where these species are magnetized. The dependence of temperature of the electrons and ions, charge of the ions, plasma background density, and strength of magnetic field on the variation of normalized growth rate has been investigated and portrayed for different channel lengths. The ion temperature gradient that generally exists in the considered plasma systems is also included to investigate its impact on the growth rate of the instability.

One of the solutions to the current fresh water challenge is desalination using low-grade heat (solar radiation or waste heat), such as Air-gap Membrane Distillation (AGMD). Based on evaporation, induced by a temperature gradient across a hydrophobic membrane, this process has an improved energy efficiency thanks to the inclusion of the air-gap by limiting the heat losses, while hindering the mass transfer at the same time. Understanding of the temperature distribution in the module is crucial for working towards improved efficiency and freshwater output.This work describes a setup and optical measurement method dedicated to analysis of energy and mass transfer resistances through temperature gradient measurement in the bulk and observation of boundary layer at the membrane. In particular data acquisition, processing and interpretation framework is presented, and compared to existing literature. Initial results indicate that the method is successful, although a number of improvements are proposed to address the identified shortcomings.

The modern insulation material for buildings is developed to prevent the overconsumption of energy by the building. The phase change material (PCM) is an excellent thermal insulation for the walls of a building, and it has become popular to study and apply this material for the construction industry. The heat transfer through the PCM is a conduction mechanism because the PCM is a medium that has no bulk motion. For this conduction mechanism, the temperature gradient is needed to calculate the amount of heat transferred through the construction wall to the inside of the building. Therefore, the investigation of the temperature gradient is beneficial for the design and energy management of the building. This study aims to investigate the temperature distribution of the PCMs related to the spatial axes of PCMs along the heat conduction direction. The purpose of this study is finding the correlation of the temperature related to the thickness of the PCM, which this purpose is useful for design the insulation wall for air-conditioned room. The methodology was to set the heat flow through the PCM in one dimension. An electric heater was used to generate heat for the hot side of the PCM. Constant temperatures of the hot side as 35, 40, 45, 50, and 55 °C were achieved. Thermocouples were used to measure the temperature at different points in one-dimension. The result shows that the thickness of the PCM has a significant effect on the temperature change. The correlation of the temperature gradient was reported. From this study, it can be concluded that the correlations of the temperature related to the thickness of the PCM and the temperature gradient are beneficial for the building design and energy management in future work.

The solar temperature field and its temperature effects on the straddle monorail tourist transportation system (SMTTS) significantly affect its mechanical performance. To investigate the distribution law of the daylight temperature field of the unpaved steel beams, the daylight temperature fields of box-type and I-sectional steel beams in different regions were measured and simulated. With the simulation results, the vertical temperature gradient curves of the unpaved steel girders were determined. Afterward, with the historical meteorological data as variables, the parameters of the extreme value model of generalized extreme value (GEV) distribution were obtained, and the representative values of temperature differences in China, based on the recurrence period, were analyzed. By analyzing the temperature difference values in 34 cities in China, an empirical prediction formula for the representative temperature difference value with three parameters was proposed, and the temperature gradient partition was established. The results indicated that the vertical temperature gradients of closed-section steel box girders are about 2–3 °C greater than that of open-section I-beams. Moreover, there are apparent geographical differences in the temperature difference values of steel girders.

In the winter of 2022-2023, a study of the crystal structure of hoarfrost horizons on the slopes of Mount Elbrus was carried out in conditions of the low-snow winter period. By means of a digital portable microscope the data were obtained, according to which, the average size of crystals of hoarfrost is 1.5- 2.5 mm, and the most frequent form of crystals of hoarfrost is flat skeletal, columnar faceted and columnar semi-skeletal forms. The study confirmed the previously observed regularity that mass transfer in the snow column depends on the magnitude of the temperature gradient, the degree of water vapor saturation in the transit zones which, among other things, are influenced by the snow cover thickness and absolute height.

The present study focuses on investigating the influence of oil and solid body temperatures on elastohydrodynamic lubrication (EHL) film formation. Experimental and numerical simulation methods are employed to examine three heating methods: oil and ball heating, disc heating, and entire system heating. A preliminary comparison between the measured results and numerical simulations confirms the impact of heating methods on film formation while validating the availability of the numerical models. Further numerical analysis reveals that in the case of oil and ball heating, the temperature gradient induced by differences in solid body temperatures plays a more significant role in film formation compared to the conventional thermal-viscosity wedge effect caused by EHL film shear. This effect is further amplified at large sliding–rolling ratios and in steel–steel contacts. The overall film formation is primarily governed by the oil inlet temperature, whereas local film formation characterized by a dimple shape is influenced by both thermal gradient effects and thermal-viscosity wedge effects. This study provides valuable insights for selecting appropriate heating methods in experiments as well as understanding how temperature differences affect film formation in practical engineering.

Composite bridges are typically exposed to temperature variations due to heat radiation, conduction, and convection. Temperature affects the modal parameters of bridges, hindering the application of damage detection methods based on the dynamic properties of bridges. In this study, the effects of temperature on the natural frequencies of composite bridges were investigated experimentally and numerically to derive a basis for separating temperature effects from the natural frequencies. A temperature-controllable girder specimen was developed for modal testing. Additionally, finite element (FE) analysis was conducted to analyze the effects of temperature. The FE analysis results were validated by comparing them to the static response results of the test specimen. The results of the experiments and FE simulations verified that temperature variation can affect the material properties, particularly the modulus of elasticity, of a composite girder, consequently influencing its natural frequency. Based on the tests and simulations, a linear relationship between the temperature and the natural frequency was proposed to remove the temperature effects from the natural frequency.