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Abstract In order to accurately and easily predict the variation of the average temperature of the concrete rectangular hollow pier. Firstly, the temperature distribution of the concrete rectangular hollow pier of Changjiahe Special Bridge was observed for 212 days. Then, based on the observation data, the functional relationship between the average concrete hollow pier temperature and the outside air temperature, and the air temperature inside the hollow pier was studied. Finally, based on this functional relationship, a prediction model for the range of variation of the mean temperature of the hollow pier was given and verified. The results of the study show that: the change of external shade temperature can be regarded as the superposition of different cyclic changes and random changes; the change rule of the average temperature of the concrete hollow pier is the same as that of the air temperature, both presenting day-by-day cyclic and step changes; the linear correlation coefficients between the daily maximum and daily minimum average hollow pier temperature and the daily average air temperature are R = 0.980 and R = 0.973, respectively; the daily average air temperature, the daily average air temperature inside the pier and daily average hollow pier temperature are R = 0.980, R = 0.998; the daily variation of the average hollow pier temperature and the daily variation of the air temperature are approximately linear, with a correlation coefficient of R = 0.899; assuming that the average temperature of the concrete hollow pier is a folding change, based on the above relationship, a method of predicting the time-by-time average temperature of the concrete hollow piers is proposed, as well as two methods of predicting the average temperature of the test piers. Average temperature change range method. Comparing the predicted values with the measured values, it is found that the predicted values are in good agreement with the measured values.

Plasmonic photothermal therapy (PPTT) involves the use of nanoparticles and near-infrared radiation to attain a temperature above 50 °C within the tumor for its thermal damage. PPTT is largely explored for superficial tumors, and its potential to treat deeper subsurface tumors is dealt feebly, requiring the assessment of thermal damage for such tumors. In this paper, the extent of thermal damage is numerically analyzed for PPTT of invasive ductal carcinoma (IDC) situated at 3–9 mm depths. The developed numerical model is validated with suitable tissue-tumor mimicking phantoms. Tumor (IDC) embedded with gold nanorods (GNRs) is subjected to broadband near-infrared radiation. The effect of various GNRs concentrations and their spatial distributions [viz. uniform distribution, intravenous delivery (peripheral distribution) and intratumoral delivery (localized distribution)] are investigated for thermal damage for subsurface tumors situated at various depths. Results show that lower GNRs concentrations lead to more uniform internal heat generation, eventually resulting in uniform temperature rise. Also, the peripheral distribution of nanoparticles provides a more uniform spatial temperature rise within the tumor. Overall, it is concluded that PPTT has potential to induce thermal damage for subsurface tumors, at depths of upto 9 mm, by proper choice of nanoparticle distribution, dose/concentration and irradiation parameters based on the tumor location. Moreover, intravenous administration of nanoparticles seems a good choice for shallower tumors, while for deeper tumors, uniform distribution is required to attain the necessary thermal damage. In the future, the algorithm may be extended further, involving 3D patient-specific tumors and through mice model-based experiments. [ABSTRACT FROM AUTHOR]

In order to accurately and easily predict the variation of the average temperature of the concrete rectangular hollow pier. Firstly, the temperature distribution of the concrete rectangular hollow pier of Changjiahe Special Bridge was observed for 212 days. Then, based on the observation data, the functional relationship between the average concrete hollow pier temperature and the outside air temperature, and the air temperature inside the hollow pier was studied. Finally, based on this functional relationship, a prediction model for the range of variation of the mean temperature of the hollow pier was given and verified. The results of the study show that: the change of external shade temperature can be regarded as the superposition of different cyclic changes and random changes; the change rule of the average temperature of the concrete hollow pier is the same as that of the air temperature, both presenting day-by-day cyclic and step changes; the linear correlation coefficients between the daily maximum and daily minimum average hollow pier temperature and the daily average air temperature are R = 0.980 and R = 0.973, respectively; the daily average air temperature, the daily average air temperature inside the pier and daily average hollow pier temperature are R = 0.980, R = 0.998; the daily variation of the average hollow pier temperature and the daily variation of the air temperature are approximately linear, with a correlation coefficient of R = 0.899; assuming that the average temperature of the concrete hollow pier is a folding change, based on the above relationship, a method of predicting the time-by-time average temperature of the concrete hollow piers is proposed, as well as two methods of predicting the average temperature of the test piers. Average temperature change range method. Comparing the predicted values with the measured values, it is found that the predicted values are in good agreement with the measured values. [ABSTRACT FROM AUTHOR]

Analytical research is carried out to investigate the effects of magneto-hydrodynamic (MHD) flow, which includes heat and mass transfer, on a system that includes a fluid to conduct electricity while it is spinning when Hall current is present. This is taking place in an environment in which there is both fluctuating mass diffusion and a temperature gradient. Using the Laplace transform method, it is possible to find solutions exactly in non-dimensions to linked partial differential problems. MATLAB was used to produce graphs that elucidate the impact that changing variables, like the impact on a number of variables, is affected by temperature, velocity and concentration. The Hall parameter (m), rotation parameter (O), Hartmann number (M), inclination angle (a) and radiation parameter (R) are all examples of such variables. The rotation parameter has been found to rise with increasing magnetic field values and angle of inclination. The axial velocity increases but the transverse velocity decreases, when Hall parameter values decrease. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Railway Science & Engineering is the property of Journal of Railway Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This is an article in the field of process mineralogy. As the raw material of high-grade quartz products，higher-purity quartz sand has strict requirements on impurity elements．Besides that，the presence of inclusions has an important impact on its purity and performance．Based on this，the fluid inclusions in the vein quartz of western Hubei Province have been studied in detail by using X-ray diffraction，plasma atomic emission spectroscopy，optical microscope，micro temperature measurement and laser Raman spectroscopy．The results show that the content of SiO2 in the ore is beyond 99.9%，and the impurity elements are mainly Al and alkali metal elements．The inclusions in the quartz are single-phase saline solution inclusions，two-phase inclusions and containing CO2 three-phase inclusions．There is no solid inclusions in the ore．The size of inclusions is mainly concentrated in 5～25 μm．The uniform temperature is 160～270 ℃ and the salinity is less than 10.00% NaCl. As a result, the ore-forming fluid belongs to medium-low temperature and low salinity fluid.According to the analysis results of the inclusion characteristics, the ore can be used as a raw material for high-purity quartz sand after deep processing and purification．

A low-carbon and energy-saving sintering process with uniform temperature distribution has been developed to address several issues associated with the sintering of drill bits in medium-frequency furnaces, namely, the large circumferential temperature differences, uneven heating of the mold, and low energy utilization. Theoretical calculations indicated that the output energy of the conventional drill bit sintering process was 12.7 kW·h, with an energy loss of 8.84 kW·h. The low-carbon sintering process achieved an output energy of 4.2 kW·h, with an energy loss of only 0.26 kW·h. Consequently, the energy utilization rates for the two processes were 30.4% and 93.8%, respectively. It was observed through the experiment that when sintering 76/49 mm drill bits at insulation temperatures of 900 °C and 1080 °C, the circumferential temperature differences in the mold were 43.7 °C and 48 °C, respectively, in the conventional drill bit sintering process. In contrast, the circumferential temperature differences in the mold were reduced to 8.7 °C and 11.3 °C, respectively, in the low-carbon and energy-saving sintering process with uniform temperature. This indicates that the average circumferential temperature difference in the mold can be reduced by 81.61% at 900 °C and by 76.46% at 1080 °C, leading to improved drill bit quality. [ABSTRACT FROM AUTHOR]

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As an important new non-metallic electronic material，higher-purity quartz sand has high requirements on impurity elements in inclusions of raw materials．Besides that ，the presence of inclusions has an important impact on its purity and performance．Based on this，the fluid inclusions in the vein quartz abroad have been studied in detail by using optical microscope, X-ray diffraction，plasma atomic emission spectroscopy，micro temperature measurement and laser Raman spectroscopy．The results show that the content of SiO2 in the ore is beyond 99.9%，and the impurity elements are mainly Al，alkali metal elements and Fe．The inclusions in the quartz are single-phase saline solution inclusions，two-phase saline solution inclusions and containing CO2 three-phase inclusions．There is no solid inclusions in the ore．The uniform temperatures of the two samples inclusions are 120～270℃ and 90～140℃．As a result，the deposit of the ore is medium-low temperature hydrothermal metamorphic quartzite．The raw ore can be used as the raw material of higher purity quartz sand after inclusion elimination and impurity reduction.

Quartz Crystal Microbalances (QCM) are widely used instruments thanks to their stability, low mass, and low cost. Nevertheless, the sensitivity to temperature is their main drawback and is often a driver for their design. Though the crystal average temperature is mostly considered as the only disturbance, temperature affects the QCM measurements also through the in-plane temperature gradients, an effect identified in the past but mostly neglected. Recently, it has been shown that this effect can prevail over that of the average temperature in implementations where the heat for thermal control is released directly on the crystal through deposited film heaters. In this study, the effect of temperature gradients for this kind of crystal is analyzed, the sensitivity of frequency to the average temperature gradient on the electrode border is determined, and a correction is proposed and verified. A numerical thermal model of the QCM has been created to determine the temperature gradients on the electrode borders. The frequency versus temperature-gradient function has been experimentally determined in different thermal conditions. The correction function has been eventually applied to a QCM implementing a crystal of the same manufacturing lot as the one used for the characterization. The residual errors after the implementation of the correction of both average temperature and temperature gradients were always lower than 5% of the initial temperature disturbance. Moreover, using the correlation between the heater power dissipation and the generated temperature gradients, it has been shown that an effective correction strategy can be based on the measurement of the power delivered to the crystal without the determination of the temperature gradient. [ABSTRACT FROM AUTHOR]

Quartz crystal microbalances are widely used sensors with applications for the detection of very-low-mass deposition in many different fields, from contamination monitoring in the high vacuum of deep space missions to the monitoring of biological activity or pollution using specifically designed active substrates. These sensors are very stable over time; nevertheless, their sensitivity to the temperature is well known, and different implementations have been devised to correct it, e.g., through compensation with a dual crystal. This paper deals with the effects of temperature on QCM but separates the case of uniform crystal temperature from the case of in-plane temperature gradients considering a QCM based on quartz crystals with deposited film resistors used as both RTDs and heaters. This configuration allows both an accurate temperature measurement and efficient thermal control, allowing the achievement of crystals temperatures in the order of 400 °C higher than the environment with a low power dissipation of the order of 1 W. The film resistors deposited around the electrodes allow directly measuring the average crystal temperature and directly delivering power to the crystal for thermal control. The localized delivery of the heat nevertheless also determines uncommon temperature fields on the crystal, and thus, an analysis of both the effects of temperature on the new microbalance was performed. The temperature gradient has strong effects on the frequency; therefore, along with the temperature, the thermal gradients have tobe compensated. The calibration of the QCM thermometers and the assessment of the achievable measurement accuracy were performed, as well as the determination of the frequency–temperature relationship. The comparison between frequency changes in the case of uniform temperature and those observed while using crystal heaters proved that temperature gradients have a strong effect on the crystal frequency. To identify the temperature field on the crystal surface of a QCM crystal, the gold coating of the deposited films was removed to achieve an emissivity acceptable for thermal imaging with an IR camera. Moreover, image processing for emissivity correction was developed. In order to correlate the temperature gradient with the frequency variation, a test campaign was performed to measure the frequency changes derived from different power levels delivered to the crystal heaters. From this test campaign and thermal analysis, the effect of the thermal gradient was assessed. [ABSTRACT FROM AUTHOR]

The self-resistance electrical (SRE) heating method to cure the carbon-fiber-reinforced polymer (CFRP) parts possesses the advantages of rapid and volumetric heating, low energy consumption, and low asset investment. But the current SRE heating methods are difficult to uniformly cure the shaped CFRP parts due to the non-uniformly distributed Joule heat power in the parts with a varying cross-sectional area. In this paper, an optimized multi-zone SRE heating method is proposed, in which the uniform heating and curing process of the shaped CFRP part is firstly achieved. By optimizing the orientation of the rectangular zones, the local overheating caused by the voltage gradient and current diffusion between different zones is notably suppressed. Combined with the electro-thermal numerical analysis, the influence of the positional offset of electrodes in two adjacent zones on the temperature uniformity is investigated. Based on this, an automated zone discretization algorithm and the optimal selection method of the zone orientation are established. The proposed method is numerically and experimentally validated with the typical-shaped CFRP parts, and the results are compared with that of the existing SRE heating method. The proposed method realizes that the maximum in-plane temperature difference of shaped CFRP parts is reduced by more than 80%. This method significantly improves the temperature uniformity of shaped CFRP parts during the multi-zone SRE heating process, which provides a potential solution for high-quality and efficient curing of CFRP parts. [ABSTRACT FROM AUTHOR]

A numerical analysis of an unsteady radiative and viscous dissipative fluid flow across a semi-infinite oscillating vertical plate with a constant temperature and mass diffusion is examined here. The fluid under consideration is optically thin gray, emitting, heat-retaining, and non-dispersing. A finite-difference approach known as the Crank−Nicolson strategy was applied to find the solution to the limitless governing equations. Applications of such engineering problems can be found in fields such as aerospace, solar power, the cooling of nuclear reactors, and chemical and mechanical engineering. Based on the computational solutions, the impacts of distinct physical parameters, such as velocity, concentration, temperature, skin friction, Nusselt number, and Sherwood number profiles, are portrayed pictorially and imparted. The numerical solution of the velocity profile developed in this study fits extremely well with what was previously published and validated. Furthermore, we discovered that plate oscillation, radiation, and viscous dissipation parameters surprisingly influence the flow pattern. [ABSTRACT FROM AUTHOR]

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Understanding the movement and distribution of insects inside a grain bin is crucial to develop an effective stored grain management protocol. The three-dimensional movement and distribution of adult Cryptolestes ferrugineus (Stephens) at 20 and 30°C were determined in a 0.7 × 0.7 × 0.7 m3 (internal dimensions) wooden box filled with wheat of uniform moisture contents (12.5 ± 0.1%, 14.5 ± 0.1%, and 16.5 ± 0.1% wet basis). The wheat at a constant moisture content was filled into 343 mesh cubes (0.1 × 0.1 × 0.1 m3) and placed inside the wooden box. The center mesh cube in the box had one hundred adult insects introduced at the beginning of the movement. After 24 h, the 343 mesh cubes were removed from the wooden box in less than 45 min. Finally, the contents of each mesh cube were sieved, and the insects counted. Each experiment was replicated three times. A maximum of 17% of insects stayed at the introduced cube (center of the wooden box). About 50–88% of the introduced adults moved downward from the introduction location at the studied temperatures and moisture contents. This 24 h study showed that C. ferrugineus movements in three dimensions follow a diffusion pattern in the horizontal direction and move downward due to the 'drift' effect and geotaxis in the vertical direction. [ABSTRACT FROM AUTHOR]

This study aimed to develop an accelerated concrete curing method based on induction heating (IH) technology. The proposed curing method provides improved heating efficiency and safety since it directly heats only the metallic forms in a non-contacting manner. It also has the advantage of being capable of heating the concrete according to a desirable heating scenario. The effects of several parameters on its performance were evaluated using a finite element method (FEM)-based thermal analysis and heating performance tests. The FEM analysis revealed the steel form to be appropriate for the IH system. The analysis also revealed that equally spaced three-turn coils yielded increased temperature uniformity in the steel form, which was verified by results of the steel form heating experiments. Furthermore, the minimum temperature generated in the form was sufficient for concrete curing. The efficiency of the use of IH for concrete curing and the effects of curing parameters were further investigated through compression tests after applications of various curing methods and by examining the temperature distributions during curing. The test results revealed early strength development even under water freezing conditions. This demonstrated the effectiveness of IH for concrete curing in cold weather. However, the efficiency decreased when the cross-sectional dimension of the specimen increased. The test results also verified that the maximum temperature and duration of induction heat curing affect the early age strength of concrete. [ABSTRACT FROM AUTHOR]

For the friction-type high-strength bolted joint, the bolt fracture can cause redistribution of interface friction, which can seriously endanger the connection safety of structural members. However, current studies barely focus on the redistribution of interface friction after bolt fracture. Therefore, this paper will specifically carry out finite element analysis on the redistribution of interface friction caused by fractured bolts. Firstly, the refined finite element model of friction-type high-strength bolted joint is used to investigate the variation of interface friction under uniform temperature as well as the distribution of interface friction in different areas. Furthermore, random selection method is introduced to explain how the quantity and location of fractured bolts influence the redistribution of interface friction. Finally, the mathematical model of friction redistribution is built to describe the redistribution of interface friction in the high-strength bolted frictional steel connection after bolt fracture. After validation, the mathematical model can well describe the redistribution of interface friction caused by fractured bolts, which can provide useful reference for the frictional steel connection design of high strength bolts. [ABSTRACT FROM AUTHOR]

Abstract Thermodynamic spreading behaviors of oil were especially important for normal operation of equipment in the state of lubricating oil starvation, which were investigated experimentally and theoretically in this manuscript. Three rough surfaces of stainless steel 316L were obtained by grinding with sandpaper 600 mesh, 1000 mesh, 1500 mesh respectively. Spreading behaviors of lubricating oil 60N were studied on these rough surfaces with uniform temperature and temperature gradient separately, which were achieved by self-assembled apparatus, and a comparison for oil spreading performance was conducted between the two temperature conditions. In order to analyze the problem theoretically, a model for rough surfaces was built by assuming the profile of any rough peak and valley to be a parabola and distributed uniformly. It was found that the higher the surface temperature and the rougher the surface, the larger the oil spreading distance and velocity for surfaces with uniform temperature. For surfaces with a temperature gradient, directional motion of oil occurred when the temperature gradient was larger than 1.61 °C/mm. Although the oil droplet had the same starting temperature, however, the spreading velocity was larger on surfaces with smaller roughness, which was opposite with that with uniform surface temperature. In addition, the theoretical model could be used to describe the stable phase after oil droplet forming a relatively stable contact angle by comparing the computational results with experimental ones under temperature gradient conditions. Graphical abstract Unlabelled Image Highlights • The spreading velocity of oil was larger on surfaces with smaller roughness under temperature gradient condition. • A theoretical model for rough surfaces was built by assuming rough peak to be a parabola and distributed uniformly. • The theoretical model could be used to describe the stable phase after oil droplet forming a relatively stable contact angle. [ABSTRACT FROM AUTHOR]

This study aimed to develop an accelerated concrete curing method based on induction heating (IH) technology. The proposed curing method provides improved heating efficiency and safety since it directly heats only the metallic forms in a non-contacting manner. It also has the advantage of being capable of heating the concrete according to a desirable heating scenario. The effects of several parameters on its performance were evaluated using a finite element method (FEM)-based thermal analysis and heating performance tests. The FEM analysis revealed the steel form to be appropriate for the IH system. The analysis also revealed that equally spaced three-turn coils yielded increased temperature uniformity in the steel form, which was verified by results of the steel form heating experiments. Furthermore, the minimum temperature generated in the form was sufficient for concrete curing. The efficiency of the use of IH for concrete curing and the effects of curing parameters were further investigated through compression tests after applications of various curing methods and by examining the temperature distributions during curing. The test results revealed early strength development even under water freezing conditions. This demonstrated the effectiveness of IH for concrete curing in cold weather. However, the efficiency decreased when the cross-sectional dimension of the specimen increased. The test results also verified that the maximum temperature and duration of induction heat curing affect the early age strength of concrete.

Solar radiation and temperature can cause the deformation of high-speed railway bridges which has an obvious effect on the position of the rails and thus on passenger comfort, especially when the bridge spans a mountainous area. In this study, the temperatures of a track-bridge system and the deflections of the tall piers belonging to a high-speed railway line in China were monitored for over three years. By adopting extreme value theory and a time-series method, the temperatures and temperature gradients of structural components of the bridge were investigated in relation to time. The results show that the monitored temperatures can be broken down into the uniform temperature and the fluctuation temperature, which cause axial deformation and structural deflection, respectively. A uniform temperature curve was fitted using the Fourier series function and then used to calculate the axial deformations for different components of the track-bridge system over a one-year period. Additionally, the extreme temperature differences estimated for a 100-year return period can be used to encapsulate the maximum values of the daily temperature difference. Thus, the proposed temperature model can effectively estimate the structure’s temperature-induced deformations. [ABSTRACT FROM AUTHOR]

In this paper, an analytical method of a thermoelastic problem for a medium with functionally graded material properties is developed in a theoretical manner for the elliptic-cylindrical coordinate system under the assumption that the material properties except for Poisson's ratio and density are assumed to vary arbitrarily with the exponential law in the radial direction. An attempt has been made to reconsider the fundamental system of equations for functionally graded solids in a two-dimensional state under thermal and mechanical loads. The general solution of displacement formulation is obtained by the introduction of appropriate transformation and carried out the analysis by taking into account the variation of inhomogeneity parameters. Furthermore, the aforementioned problem degenerated into the problem of the circular region by applying limiting conditions, and the results are validated. Numerical computations are carried out for ceramicmetal-based functionally graded material, in which zirconia is selected as ceramic and aluminium as metal and are represented graphically. [ABSTRACT FROM AUTHOR]

The effects of temperature load on the dynamic responses of cable-stayed bridges have attracted the attention of researchers in recent years. However, these investigations mainly focus on the influence of temperature on the dynamic characteristics of structures, such as vibration mode and frequency. This paper discusses the effects of uniform temperature changes on the seismic responses of a cable-stayed bridge. A three dimensional finite element model of a cable-stayed bridge using OpenSees is established for nonlinear time history analysis, and uniform temperature load is applied to the prototype bridge before the conducting of seismic excitation. Three ground motion records are selected from the PEER strong motion database based on the design spectrum. Case studies are then performed considering the varying temperature and the connections between the deck and pylons of the bridge. The result shows that the seismic responses of the bridge are significantly increased with the consideration of temperature load. Meanwhile, the types between the deck and pylon also have notable impacts on the seismic responses of the bridge with and without temperature changes. This research could provide a reference for designers during the design phase of cable-stayed brides. [ABSTRACT FROM AUTHOR]

In PEM fuel cells, during electrochemical generation of electricity more than half of the chemical energy of hydrogen is converted to heat. This heat of reactions, if not exhausted properly, would impair the performance and durability of the cell. In general, large scale PEM fuel cells are cooled by liquid water that circulates through coolant flow channels formed in bipolar plates or in dedicated cooling plates. In this paper, a numerical method has been presented to study cooling and temperature distribution of a polymer membrane fuel cell stack. The heat flux on the cooling plate is variable. A three-dimensional model of fluid flow and heat transfer in cooling plates with 15 cm × 15 cm square area is considered and the performances of four different coolant flow field designs, parallel field and serpentine fields are compared in terms of maximum surface temperature, temperature uniformity and pressure drop characteristics. By comparing the results in two cases, the constant and variable heat flux, it is observed that applying constant heat flux instead of variable heat flux which is actually occurring in the fuel cells is not an accurate assumption. The numerical results indicated that the straight flow field model has temperature uniformity index and almost the same temperature difference with the serpentine models, while its pressure drop is less than all of the serpentine models. Another important advantage of this model is the much easier design and building than the spiral models. [ABSTRACT FROM AUTHOR]

The controlling of heat transport procedures through external energy source effects is one of the mainly significant problems in modern applied physical sciences. Major strong research in thermal sciences, mechanical engineering and including energy modeling, planning and energy supervisions, energy conservations, energy efficiencies, biomass and bio-energy, renewable energy, energy storage, energy in buildings. In the current existing paper, the consequences of thermal conductivity on temperature, this is inversely proportionally by the linear function of temperature on free convective movement of an incompressible viscous fluid through the heated uniform and vertical wavy surface is examined. Associated with boundary conditions, the governing boundary layer equations be translated into the non-dimensional structure for phenomenon by utilizing an appropriate transformation. In the domain of vertical plate that is flat, the resulting method of nonlinear partial differentiated equations are mapped and then numerically by applying the implicit finite difference technique with Keller-box technique. The rate of heat transfer, the skin friction coefficient, the isotherms and streamlines throughout the boundary layer are exhibited graphically. • The thermal conductivity on temperature, this is inversely proportionally by the linear functions of temperature studied. • The free convective flow of viscous fluid through the heated uniform and perpendicular wavy surface is examined. • The governing boundary layer equations with boundary conditions solved by utilizing an appropriate transformation. • The nonlinear partial differential equations are then using finite difference implicit scheme with Keller-box technique. • The rate of heat transfer, the skin friction coefficient, the isotherms and streamlines are exhibit graphically. [ABSTRACT FROM AUTHOR]

We systematically derive models that would be suitable to describe flows of compressible fluids with the material moduli depending on the symmetric part of the velocity gradient and temperature, within the context of a thermodynamic framework that has been quite successful in developing models to describe the response of bodies that produce entropy while undergoing processes. [ABSTRACT FROM AUTHOR]

The purpose of this study has been to demonstrate the possibilities of uniform heating of a cavity, with great accuracy, by means of an integrated resistor built with the same dimensions as the cavity, i.e., with a high level of integration. For application purposes, a compact resistor allows increasing the number of cavities in which temperature can be independently controlled on the same substrate, which can prove critical for high-throughput screening applications. Potential applications lie in the field of biology or chemistry. In order to achieve the desired result, an optimization procedure was performed on the shape of the resistor. The heater size reduction enables a high level of integration with a reduced heating source surface area. Resistor shape has been optimized to reduce the influence of boundary effects, using improvements introduced in genetic algorithms. An experimental validation of the temperature profile inside the cavity has been carried out using a dye whose fluorescence depends on temperature, i.e., Rhodamine B, it will be shown herein that the optimized resistor allows for temperature cycling, e.g., for PCR applications. [ABSTRACT FROM AUTHOR]

In this study, an elastic-plastic stress analysis is carried out on a composite thermoplastic disc reinforced by steel fibers, curvilinear. Radial and tangential stresses are obtained under a uniform temperature distribution. Thermal stresses occur in the disc for the uniform temperature distribution due to the different thermal expansions in radial and tangential directions. The magnitude of the tangential stress component for elastic and elastic-plastic cases is higher than that of the radial stress component. The tangential stress component is compressive and tensile on the inner and outer surfaces, respectively. It is the highest on the inner surface. The elastic-plastic solution is performed for the plastic region expanded around the inner and outer surfaces by an analytical formulation and a numerical solution. The solution is also carried out by the finite element method (ANSYS solution). These two solutions give similar results. The intensities of the residual stress component of the tangential stress and plastic flow are the highest at the inner surface. [ABSTRACT FROM AUTHOR]

Numerical results on the thermal buckling temperature of geometrically perfect HS-Graphite/Epoxy hemispherical shells with cut-out at apex subjected to uniform temperature distribution is presented. The numerical computation is based on the general shell of revolution semi-analytical finite element applicable to moderately thick shells. Studies are presented considering parameters like ratio of base radius to thickness of shell, size of the cut-out at apex and fibre orientation of the lamina and their effects are examined on the magnitude of the buckling temperature. An in-depth study on the magnitude and distribution of the total effective stress resultants and moment resultants is used to explain the role of these quantities on the magnitude of the lowest thermal buckling temperature. It is found that for a given geometry, uniform temperature rise and edge conditions the lowest buckling temperature of a hemispherical shell is mainly due to the large magnitude of the hoop stress resultant close to the edges of the hemispherical shell and also depends on the distribution of hoop stress resultants. [Copyright &y& Elsevier]

• A novel stack design is proposed to improve internal thermal distribution. • The effect of stack design variables on heat transfer mechanism is elucidated. • Thermal resistance of the path to manifold affects planar temperature distribution. • Reduced gaseous heat transfer in each unit causes vertical conduction to increase. • Strengthened vertical conduction promotes gas pre-heating at the bottom of a stack. Solid oxide fuel cell (SOFC) is a promising technology for stable power supply with high efficiency and high quality heat utilization, but it still faces the technical challenge of low long-term durability caused by thermal imbalance of its stack. An effective, novel thermal management method is urgently required for its market deployment. This study proposes a novel interconnect design for effective thermal management and elucidates the influence of its design variables on internal thermal conditions and heat transfer characteristics of a 1-kW planar SOFC stack. Three-dimensional thermo-fluid simulations are performed on the new stack design employing the novel interconnect and the conventional stack design for comparison. The new design is developed for the purpose of uniform in-plane (horizontal) temperature distribution by modifying the displacement of gas manifolds. At the repeating-unit scale, due to the reduced thermal resistance for horizontal heat transfer of the new stack, its in-plane temperature deviation decreases by 35–60 °C. At the stack scale with 30 unit-cells stacked vertically, the average temperature increases by 30 °C, and the vertical temperature difference decreases by 50 °C. Such thermal fields are the combined results of reduced gaseous convection and enhanced vertical solid-phase conduction through each repeating unit. In the new stack, the amount of heat transferred to the gas within each repeating unit is generally decreased, but is recuperated by increasing solid conduction through metallic interconnects. The relatively weakened gaseous heat transfer of the new design provides more thermal load at the lowest unit of the stack than the reference design, which promotes gas pre-heating prior to reaching the unit-cells and hence results in the elevated stack temperature. Such gas pre-heating also reduces the temperature difference in the vertical direction of the new design. The lower temperature differences both in horizontal and vertical directions enable the new stack to reduce its thermal imbalance and potentially to improve long-term durability. [ABSTRACT FROM AUTHOR]

During cold dynamic gas spray additive manufacturing, the thermal field within particles is generally simplified by a state of an instantaneous uniform distribution over the particle's media at any position inside and outside the De-Laval nozzle. This paper addresses critical discussions using analytical and computational analysis of the transient heat transfer within the solid particles due to the convective exchange with the flowing gas. An analytical criterion depicts conditions of instantaneous uniform temperature over the range of typical cold spray data including various particle thermal conductivity, particle size range, dragging velocities, gas nature and gas setting conditions. The analytical depiction draws the conclusion that, during cold spraying, the temperature field within particles is mostly instantaneously uniform. The notion of instantaneousness is further investigated via computational analysis of the transient thermal gradient regimes within particles. The phenomenological computations enable to characterize the duration of the transient stage prior to the state of uniform temperature. Comparisons with analytical particle's residence time using various scales of travelled distance give a more relevant notion of instantaneousness. The particle temperature is not strictly instantaneously uniform. However, such instantaneousness prevails for a covered distance unit of 1 mm which is widely enacted in the literature to compute the particles temperature during cold spraying. As conclusive remarks, issues due to this instantaneousness of the particle temperature are reviewed and suitable alternatives for efficiently heating the particles during cold spraying are reported. [ABSTRACT FROM AUTHOR]