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Flash sintering of ceramic powders is a complex process that involves electric, thermal and mechanical phenomena. Modelling should help to better understand and control it, with a view to producing safe and homogeneous parts. A finite element model that couples all relevant phenomena, including the densification and shrinkage of the sintering material, has been worked out for this purpose. This model is used here to investigate the flash sintering of disk-shaped parts. Particular attention is paid to the appearance and growth of heterogeneities within the part, known as hot spots, which are highly dependent on material and process parameters. Leads are provided for limiting the development of such heterogeneities. [ABSTRACT FROM AUTHOR]

The Inconel 718 superalloy, a precipitation-hardenable material, is of particular interest for applications involving components operating under extreme conditions due to its excellent mechanical properties, high corrosion resistance at temperatures up to 700 °C, and good workability. At high temperatures, thermal transfer processes are crucial for temperature distribution across the component's section, structural transformations, and variations in the alloy's properties. The history of accidental overheating events is critical for the microstructure and properties of the alloy. Studies on thermal transfer in the Inconel 718 alloy available in the literature typically focus on the alloy in its as-delivered state. The experimental research presented in this paper examines the influence of repeated overheating history on the thermal diffusivity of the alloy. [ABSTRACT FROM AUTHOR]

Gambiered Guangdong silk, which involves an eco-friendly processing technique, unique double-sided structure and excellent wearing properties, is an ecological textile dyed with the pigment extracted from Dioscorea Cirrhosa Lour. There have been a lot of reports on the structure and properties of the silk. As a summer cooling fabric, gambiered Guangdong silk has excellent thermal and moisture comfort properties such as coolness, breathability, and moisture permeability. However, the study of the evolution of thermal-moisture comfort during the preparation of gambiered Guangdong silk has not been reported in the literature. Thus, this study attempts to clarify the evolution of the thermal comfort and moisture comfort based on the traditional preparation process of gambiered Guangdong silk. In this experiment, gambiered Guangdong silk was prepared according to the traditional processing technology. Firstly, pigment was extracted from Dioscorea Cirrhosa Lour. Then, the white silk fabric was dyed with the pigment, and exposed to the sun. This dyeing-exposure process was repeated about 20 times. Subsequently, when the pigmentation on the fabric reached a certain thickness, the silk was coated with mud. Finally, because the dyed and mud-coated fabrics were stiffer, fabrics were finished by sand washing. According to the characterization of the thermal performance test, there was negligible alteration in thermal conductivity, thermal diffusivity, specific heat capacity, the Clo value, warmth retention rate and heat transfer coefficient. The result show that the heat transfer index of the fabric remained relatively stable during the preparation process, demonstrating the same excellent heat transfer performance (cooling characteristics) as the blank silk fabrics of the same specification. Furthermore, the moisture comfort of gambiered Guangdong silk was clarified. During the manufacturing processing of gambiered Guangdong silk, the breathability of the fabric gradually decreased. There was no significant difference in moisture permeability. The moisture regain rate increased whereas the saturated water absorption rate decreased. After dyeing and mud coating, the fabric had good wettability and unidirectional water transfer. After sand washing, the fabric was hydrophobic and had no moisture absorption and conductivity. The results show that gambiered Guangdong silk has excellent moisture comfort. Finally, in order to verify that the thermal-moisture comfort of gambiered Guangdong silk is related to the formation of the coating structure of the fabric, the surface morphology of the fabric was observed and analyzed. From the SEM images, it can be observed that the tight coating structure is formed on the surface of the silk, and the pores between the fibers are reduced. That is why gambiered Guangdong silk has outstanding thermal-moisture transfer properties after dyeing and mud coating. Through the analysis of the surface morphology of the silk, it is obvious that the surface of the fabric is damaged and the fibers are broken and fleece after sand washing. That is why the silk has hydrophobic property. This study clarifies the evolution of the thermal-moisture comfort in the preparation process of gambiered Guangdong silk and may pave the path for the standardization of its industrial production. [ABSTRACT FROM AUTHOR]

African scientific research faces formidable challenges, particularly with limited access to state-of-the-art measurement instruments. The high cost associated with these devices presents a significant barrier for regional research laboratories, impeding their ability to conduct sophisticated experiments and gather precise data. This predicament not only hampers the individual laboratories but also has broader implications for the African scientific community and the advancement of knowledge in developing nations—the financial cost barrier considerably impacts the research quality of these laboratories. Reflection on technical and economical solutions needs to be quickly found to help these countries advance their research. In civil engineering, the thermal conductivity property is the most important measurement for characterizing heat transfer in construction materials. Existing devices (i.e., conductometers) in a laboratory are expensive (approximately EUR 30,000) and unavailable for some African laboratories. This study proposes a new and affordable device to evaluate thermal conductivity in construction materials. The method involves establishing a thermal flux between a heat source (from the Joule effect provided by steel wool where a current is circulating) and a cold source (generated by ice cubes) under steady-state conditions. The development of the cylindrical prototype is based on the comparative flux-meter method outlined in the measuring protocol of the ASTM E1225 standard document. Experiments were conducted on four distinct materials (polystyrene, wood, agglomerated wood, and rigid foam). The results indicate a correct correlation between the experimental values obtained from the newly developed prototype and the reference values found in the literature. For example, concerning the experimental polystyrene study, the detailed case analysis reveals a good correlation, with a deviation of only 4.88%. The percent error found falls within the acceptable range indicated by the standard recommendations of the ASTM E1225 standard, i.e., within 5% acceptable error. [ABSTRACT FROM AUTHOR]

African scientific research faces formidable challenges, particularly with limited access to state-of-the-art measurement instruments. The high cost associated with these devices presents a significant barrier for regional research laboratories, impeding their ability to conduct sophisticated experiments and gather precise data. This predicament not only hampers the individual laboratories but also has broader implications for the African scientific community and the advancement of knowledge in developing nations—the financial cost barrier considerably impacts the research quality of these laboratories. Reflection on technical and economical solutions needs to be quickly found to help these countries advance their research. In civil engineering, the thermal conductivity property is the most important measurement for characterizing heat transfer in construction materials. Existing devices (i.e., conductometers) in a laboratory are expensive (approximately EUR 30,000) and unavailable for some African laboratories. This study proposes a new and affordable device to evaluate thermal conductivity in construction materials. The method involves establishing a thermal flux between a heat source (from the Joule effect provided by steel wool where a current is circulating) and a cold source (generated by ice cubes) under steady-state conditions. The development of the cylindrical prototype is based on the comparative flux-meter method outlined in the measuring protocol of the ASTM E1225 standard document. Experiments were conducted on four distinct materials (polystyrene, wood, agglomerated wood, and rigid foam). The results indicate a correct correlation between the experimental values obtained from the newly developed prototype and the reference values found in the literature. For example, concerning the experimental polystyrene study, the detailed case analysis reveals a good correlation, with a deviation of only 4.88%. The percent error found falls within the acceptable range indicated by the standard recommendations of the ASTM E1225 standard, i.e., within 5% acceptable error.

This study examines the behavior of an unsteady magnetohydrodynamic Casson fluid past over an exponentially accelerated vertical plate in a rotating system. The flow is driven by the combined effects of thermal radiation, heat source/sink, chemical reaction and Hall current taken into account. The non-dimensional equations governing the system are solved using the Laplace transform technique, yielding expressions that offer insights into velocity, temperature and concentration profiles. The axial velocity decreases with increasing thermal radiation and chemical reaction, while it increases with Casson and heat source/sink. The current findings are compared with previous studies, revealing substantial agreement. Additionally, the study examines skin friction, heat transfer and mass transfer rates. The insights gained from the heat transport processes have implications across various applications in cooling systems, aerospace engineering and energy storage technologies. The results of this study have direct relevance in engineering applications and are determined analytically. [ABSTRACT FROM AUTHOR]

In recent years, scientists have begun to search for more sustainable biomaterials. Although many studies have been conducted on different fiber-reinforced composites, much remains to be done. Using environmentally friendly composite materials for building insulation is a practical solution to reduce energy consumption. In this study, an advanced statistical approach using JMP software was adopted to manage a complex problem involving multiple parameters. This method was applied to optimize the thermal insulation characteristics of a bio-composite. By following a precisely designed experimental program. the study focuses on analyzing the impact of varying concentrations of date palm fibers (DPF) on the thermal properties of the material. The tested samples contained between 0% and 30% DPF. with a fiber length set at 7 mm. The findings of this study clearly illustrate that the thermal conductivity of the bio-composite decreases with an increase in the percentage of DPF. This phenomenon occurs because the incorporation of fibers into the composite enhances the porosity within the matrix. consequently, reducing its density. Thus. these results underscore the advantageous effect of DPF on the insulation properties of the material. [ABSTRACT FROM AUTHOR]

The experimental and theoretical analysis of viscous dissipation and heat generation/absorption management is crucial in engineering, medical, biological, and exploration activities. This study investigates the analytical solution of viscous heating and thermal gyration of magneto-micropolar fluid particles across a resistive medium with internal non-uniform heat generation/absorption. The formulated partial differential equations were appropriately converted into coupled ordinary differential equations employing similarity variables along with the boundary conditions. The simulation of the resultant equations is carried out using the collocating weighted residual scheme, and the result is validated using the shooting technique via the Runge-Kutta method of order four, Adomian decomposition technique, variational iteration scheme, differential transform method, and quasi-linearization technique as the control methods. Tabular and graphical representations are provided to illustrate the flow characteristics. Taking from the results, the existence of a magnetic field retards the gyration of the fluid particle motion. The spin gradient and vortex viscosity terms reveal the reverse occurrence of micro-rotation distribution, and it is seen that the porosity term suppresses the velocity field. Furthermore, it is observed that the parameters that enhance internal heat generation decrease the viscosity of the fluid in the region. Hence, these findings will assist scientists and engineers to effectively manage heat generation/absorption in industries where effective heat transfer activities are crucial to achieving ideal performance and reducing energy waste.

The thermal behavior of the cladding layer and the flow behavior of the molten pool significantly affect the geometry, temperature distribution and microstructure of the cladding track, thus affecting the mechanical properties of the cladding. Based on the interaction between the laser and powders, a calculation method of the cross-sectional area of the cladding track is proposed. The droplet energy method and the moving grid method are first combined to establish the surface growth model of the cladding track, to calculate the geometry of the cladding track. Then, the temperature field and flow field of the cladding track are studied. The driving forces of the molten pool flow including shear viscosity, gravity, buoyancy, surface tension at the gas-liquid boundary and pressure between liquids are considered to carry out the dynamics study of the molten pool. According to the force condition of the infinitesimal in the molten pool, the dynamic rules and boundary rules of the molten pool are established, so as to solve the flow field of the molten pool. In addition, the calculated geometry of the cladding track is compared with the experimental result to verify the accuracy of the model, and the microhardness of the cladding track is measured. The results show that the relative error between the simulation and the experiment is less than 6%, and the microhardness of the cladding layer is significantly improved. This work can provide a method for studying the morphology, temperature field, and flow field of laser cladding.

A detailed study of the erratic circulation around an unbounded inclined plate under fluctuating temperature and isothermal mass dispersion was carried out with a chemical reaction. This work concentrated on the harmonic inclination of the plate in its plane, and the accurate solution of the non-dimensional governing formulations was made possible by the Laplace transform technique. To evaluate their impact on different profiles, the investigation examined a variety of physical factors, including phase inclination, chemical response variable, Schmidt number, thermal Grashof number, mass Grashof number, and duration. Notably, the speed per second increased with decreasing phase angle. Furthermore, a decrease in either the thermal radiation variable or the chemical response variable induced an increase in velocity. [ABSTRACT FROM AUTHOR]

The Inconel 718 superalloy, a precipitation-hardenable material, is of particular interest for applications involving components operating under extreme conditions due to its excellent mechanical properties, high corrosion resistance at temperatures up to 700 °C, and good workability. At high temperatures, thermal transfer processes are crucial for temperature distribution across the component’s section, structural transformations, and variations in the alloy’s properties. The history of accidental overheating events is critical for the microstructure and properties of the alloy. Studies on thermal transfer in the Inconel 718 alloy available in the literature typically focus on the alloy in its as-delivered state. The experimental research presented in this paper examines the influence of repeated overheating history on the thermal diffusivity of the alloy.

In industrial processes such as machining, molding, disc brake operation, and spot welding, the thermal transfer at solid-solid interfaces, particularly with heat generation at the interface, is a critical area of study. This research presents a theoretical framework for addressing the direct problem of thermal conduction in electro-thermal contacts, with a focus on short-term scenarios where heat dissipation occurs through the Joule effect. This aspect, not extensively explored in existing literature, is investigated using a semianalytical method. The study also encompasses a simulation-based exploration, aimed at deepening the understanding of physical phenomena at the contact level. Special attention is given to the thermal transfers initiated at the asperity level of the electro-thermal contact. Findings from this investigation underscore the significance of incorporating the thermal diffusivity of materials into the model for achieving convergence. A notable observation is the increasing divergence over time between the temperatures predicted by numerical and analytical solutions, a trend more pronounced in materials with higher thermal diffusivity, such as titanium. This research contributes valuable insights into the modeling of contact parameters essential for simulating various industrial applications, potentially enhancing efficiency and efficacy in thermal engineering practices. [ABSTRACT FROM AUTHOR]

The traditional curing methods for thermosetting resins are energy-inefficient and environmentally unfriendly. Frontal polymerization (FP) is a self-sustaining process relying on the exothermic heat of polymerization. During FP, the external energy input (such as UV light input or heating) is only required at the initial stage to trigger a localized reaction front. FP is regarded as the rapid and energy-efficient manufacturing of polymers. The precise control of FP is essential for several manufacturing technologies, such as 3D printing, depending on the materials and the coupling of thermal transfer and polymerization. In this review, recent progress on the materials, modeling, and application of FP for thermosetting resins are presented. First, the effects of resin formulations and mixed fillers on FP behavior are discussed. Then, the basic mathematical model and reaction-thermal transfer model of FP are introduced. After that, recent developments in FP-based manufacturing applications are introduced in detail. Finally, this review outlines a roadmap for future research in this field. [ABSTRACT FROM AUTHOR]

This article aims to help the specialists and the experts in the field of document examination, with the presentation of some cases of counterfeit/forgery travel documents for the achievement of which were used some advanced methods and techniques. So, the counterfeits become more and more advanced, trying to imitate as good as it can be, graphic elements and security features, being in trend with the latest printing techniques implemented to the genuine travel documents. Regarding forgeries, there is an increased attention given to the area of the owner's photo, which is most often subjected to the process of alteration through various procedures. In this article were used techniques, instruments and research methods such as observation, examination and comparison of documents. [ABSTRACT FROM AUTHOR]

To comprehensively investigate the evolution of the stress field, a three-dimensional thermodynamic model of laser cladding was developed in this paper. By analyzing the physical process and constructing a mathematical model, the temperature transfer and stress distribution were calculated. The simulation examined the evolution and distribution of stress at various scanning speeds, discussing the interplay between the temperature field and the stress field during rapid heating and cooling. Residual stress was measured through X-ray diffraction in experiments, and the crack distribution within the cladding layer was observed. The findings indicated that the stress values calculated from the simulation model aligned well with the experimental results. By combining experimental data, we conducted a qualitative analysis of the distribution of residual stresses and the trends of crack initiation, leading to the proposal of an optimized processing scheme that significantly enhances the quality and reliability of the cladding layer.

Both oxyhydrogen and butanol are renewable alternative fuels. Based on gasoline/butanol compound injection mode, although the introduction of oxyhydrogen can effectually enhance the optimal BDIr (butanol direct injection ratio), it also leads to an increase in NO emission. Therefore, this paper further studies the influence of lean-burn on the combustion and emission of ternary-fuel combined supply engine with oxyhydrogen/butanol/gasoline. In this paper, three variables are set, namely five BDIr (0–80%), five ONPIv (oxyhydrogen negative pressure inhalation volume) (0–16 L/min) and five λ (1.0–1.4). The results show that the larger the λ, the more significant the impact of oxyhydrogen on improving combustion and thermal transfer inside the cylinder. With the increase of ONPIv, CoVIMEP, CA 10–90 and CA 0-10 decrease, IMEP increases. Under all lean-burn conditions, ONPI can reduce CO and HC emissions. Under the condition of λ = 1.4, when ONPIv = 16 L/min, NO emission is 49.98% lower than the value of the original engine. Moreover, based on BDIr = 40%, 16 L/min ONPIv can elevate the λ limit from 1.41 to 1.83. In summary, “1.1 = λ ≤ 1.2+ONPIv = 16 L/min+60%≤BDIr≤80%” is the excellent control strategy of ONPI + BDI + GPI engine. The synergistic influence of lean-burn and larger BDIr can greatly reduce gasoline consumption and NOx emission caused by oxyhydrogen, but also worsen the mixture combustion atmosphere. ONPI can effectively improve this problem, and further increase energy efficiency. The coupling technology of ternary-fuel combined supply and lean-burn has a positive impact on improving thermal transfer efficiency, optimizing mixture combustion and decreasing gaseous emission.

Superhydrophobic surfaces wit ordered hierarchical microstructures were prepared on copper substrates by combining thermal transfer and etching. The surface morphology, wettability, chemical composition and corrosion resistance were, respectively, characterized via scanning electron microscopy, a three-dimensional confocal microscope, contact angle measurement, X-ray diffraction, X-ray photoelectron spectroscopy, electrokinetic polarization and electrochemical impedance spectroscopy techniques. The contact angle of the obtained superhydrophobic surface is up to 153.3° with a reduction in the corrosion current density from 3.9105 × 10−5 A/cm2 to 3.5421 × 10−6 A/cm2 via the electrokinetic polarization curve test, and the maximum capacitive arc radius of the superhydrophobic surface is about 2.5 × 104 Ω cm2 via the electrochemical impedance spectroscopy test, which is two orders of magnitude higher than that of bare copper substrate, and the maximum modulus value |Z| is also two orders of magnitude higher than that of bare copper substrate, indicating that the superhydrophobic surface has better corrosion resistance. This method provides an effective etching approach toward preparing superhydrophobic surfaces with ordered microstructures. [ABSTRACT FROM AUTHOR]

The traditional curing methods for thermosetting resins are energy-inefficient and environmentally unfriendly. Frontal polymerization (FP) is a self-sustaining process relying on the exothermic heat of polymerization. During FP, the external energy input (such as UV light input or heating) is only required at the initial stage to trigger a localized reaction front. FP is regarded as the rapid and energy-efficient manufacturing of polymers. The precise control of FP is essential for several manufacturing technologies, such as 3D printing, depending on the materials and the coupling of thermal transfer and polymerization. In this review, recent progress on the materials, modeling, and application of FP for thermosetting resins are presented. First, the effects of resin formulations and mixed fillers on FP behavior are discussed. Then, the basic mathematical model and reaction-thermal transfer model of FP are introduced. After that, recent developments in FP-based manufacturing applications are introduced in detail. Finally, this review outlines a roadmap for future research in this field.

Efficient breaking of hard mineral rocks is an important prerequisite for deep metal mining. In order to study the rock breaking mechanism of abrasive water jet erosion of high-temperature hard rock in deep ground, the temperature deformation evolution law during the process of jet impact on rocks was simulated and experimentally studied. The results show that the distribution of jet pressure, jet velocity, and jet turbulent kinetic energy near the residence point of the jet impingement wall is generally high in the middle and low in the outside. The heat transfer distance r on the rock surface is approximately (1.5–2.0) times the nozzle diameter, and the heat transfer distance inside the rock is (1.0–1.5) times the nozzle diameter. The maximum heat flux density at the jet cooling wetting boundary can reach 450 W/mm2. Within 0–3 seconds of the erosion process, the average surface temperature sharply decreases and exhibits a downward trend of jet stagnation point radiating outward. The radius of jet cooling influence gradually increases. Due to the impact cooling effect, tensile stress is generated at the top of the rock sample, and the tensile stress in the lower part of the rock is converted into compressive stress. With the increase of jet pressure and treatment temperature, the area and range of erosion pits significantly increase, and there is a significant phenomenon of thermal cracking around the erosion pits. The research conclusion can provide new ideas and basis for hydraulic breaking of high-temperature hard rocks in deep ground. [ABSTRACT FROM AUTHOR]

Project management allows the planning the processes, products, and services necessary for the development of heat transfer calculations. This research developed a solar reactor prototype with an operating temperature range of 170 to 240 °C by deploying project life cycles and the irradiance received in Guadalajara (Mexico). Project management uses the processes of initiation, planning, execution, monitoring, and closure. A conceptually designed solar collector captured the radiation, assuming an irradiance of 1000 W/m2. The startup processes were used to estimate the temperature in the reactor chamber by transfer heat calculations (radiation, convection, and conduction). The planning, execution, and monitoring processes were used to develop the prototype, and closing processes were used to validate its operation through temperature and solar irradiance measurements. The solar reactor prototype provided evidence of its ability to reach an average temperature of 188 °C in a steady state and to receive an average irradiance of 1260 W/m2 in autumn. Heat transfer calculations are valid for developing reactors that work with solar energy and are helpful in geographical areas with similar irradiances. [ABSTRACT FROM AUTHOR]

Innovative technologies necessitate extra energy, which can be captured from environmentally sustainable, renewable solar energy. Here, heat and mass transfer through stirring nanofluids in solar collectors for direct absorption of sunlight are pronounced. The similarity transformation served to turn mathematically regulated partial differential equations into sets of nonlinear higher-order ordinary differential equations. These equations have been resolved by the homotopy analysis method manipulating, BVPh2.0 package in Mathematica 12.1. Validations are justified through comparison. Afterward, stronger magnetic field interactions delay the nanofluids mobility. Temperature increases with thermal radiation and Biot numbers. Entropy formation and nanoparticle concentration dwindle when Schmidt's number surges. [ABSTRACT FROM AUTHOR]

Flexible wearable strain sensors are becoming increasingly popular due to their ability to monitor physiological signals and to detect motion in a wide range of applications. However, the development of strain sensors with high sensitivity and wide sensing range remains a challenge. Herein, a film-nanowire double sensoring layer structure (FNDLS) crack strain sensor with high sensitivity, wide strain range and fast response is proposed. The FNDLS with hierarchical synergistic are integrated onto fabrics using a heat pressing process. The FNDLS has a very low initial resistance and a high density of channel cracks to have the high sensitivity of the strain sensor and to extend the strain range of the strain sensor through the synergistic bridging effect of the AgNWs. Due to this structure, the sensitivity of the sensor can reach 70945 , the strain range can reach about 40 %, and response time is less than 129 ms. Furthermore, the sensor demonstrates exceptional cycling stability and favourable frequency characteristics. Its superior performance makes it suitable for monitoring pulse waves and detecting motion through smart clothing. [Display omitted] • Strain sensors with a double conductive layer based on heat pressing method. • Strain sensors has ultra-high sensitivity, wide strain range and fast response. • Sensor can be used for pulse wave monitoring and fitness motion correction. [ABSTRACT FROM AUTHOR]

The main objective of the paper is optimization of the process of thermal transfer in order to obtain - with minimum number of tests and maximum precision - a high adhesion degree of stencils applied to the garments. The major factors affecting the thermal transfer processes are: temperature, pressure, time, and the characteristics of the textile (fiber composition, finishing, structure of the face surface, etc.). The problem is current for most companies that produce clothing for sports and outdoor activities. This category of products is quite complex due to processing technology, combinations of various textile components, cutout components and most importantly the informative and decorative elements applied through thermal transfer process. To optimize the thermal transfer process, a series of experiments with a central rotating compound were applied. Analysis and Interpretation of the results showed that the pressing time is the most important factor of the adhesion of the thermal transfer to the textile material and its ulterior resistance to washing.

Temperature‐dependent photoluminescence (PL) properties of high quality cubic phase α‐CsPbI3 nanocrystals are investigated, and thermal transfer from free excitons to trapped excitons is observed. Free exciton recombination is the main origin of the high PL quantum yield (97%) at room temperature. Little change of PL peak energy is observed with decreasing temperature from 280 to 200 K, and it shifts from 1.84 to 1.81 eV in the region of 200 and 80 K. The PL peak intensity decreases with decreasing temperature first and then increases, and the minimum value is observed at 180 K. Two PL bands are obtained by Gaussian fittings in the PL spectra detected at different temperatures, and the high energy band is attributed to the emission of free excitons, while that for the low energy band is related to the transition of trapped excitons. The PL integrated intensity ratio of trapped exciton and free exciton transition increases from 0.18 to 2.10 with decreasing the temperature, which suggests that thermal transfer from free exciton to trapped exciton states leads to the dominant optical emission of trapped exciton recombination in the low temperature region. [ABSTRACT FROM AUTHOR]

Micro-meteorological studies of urban flow and pollution dispersion often assume a neutral atmosphere and often the three-dimensional variation in temperature fields and flow around buildings is neglected in most building energy balance models. The aim of this work is to present the results of development and validation of a three-dimensional tool coupling thermal energy balance of the buildings and modelling of the atmospheric flow and dispersion in urban areas. To do so, a 3D microscale atmospheric radiative scheme has been developed in the atmospheric module of the computational fluid dynamics (CFD) code Code_Saturne adapted to detailed building geometries. The full coupling of the radiative transfer and fluid dynamics models has been validated with idealized cases. In this paper, our focus is to simulate and compare with measurements the diurnal evolution of the brightness surface temperatures and the momentum and energy fluxes for a neighborhood in the city center of Toulouse, in the southwest part of France. This is performed by taking into account the 3D effects of the flow around the buildings and all thermal exchanges, in real meteorological conditions, and compare them to aircraft infrared images and in situ measurements on a meteorological mast. The calculation mesh developed for the city center and the simulation conditions for the selected day of the field campaign are presented. The results are evaluated with the measurements from the Canopy and Aerosol Particles Interactions in TOulouse Urban Layer experiment (CAPITOUL). In addition, the second purpose of this work is to investigate a hypothetical release of passive pollutant dispersion in the same area of Toulouse under different thermal transfer conditions for the street and the buildings surfaces: neutral and 3D radiative transfer heating. The presence of heat transfer continually modifies the airflow field while the airflow in the neutral case reaches a stationary state. Compared to the neutral case, taking into account the thermal transfer enhances the turbulence kinetic energy and vertical velocity (especially at the roof level) due to buoyancy forces. The simulation results also show that the thermal effects considerably alter the plume shape. [ABSTRACT FROM AUTHOR]

In this article, we are interested in flexible modeling and performing solution of transient thermal selective laser melting problems. For this, we first introduce a finite addition of matter elements method (FAMEM) to generate any wished finite sequence of thermal problems, defined in additively constructed domains. Second, we use the multiscale Arlequin frame‐work to develop a three‐level Arlequin weak‐strong formulation of each problem of the finite sequence. Two Arlequin patches are used in the latter to localize the steepest thermal gradients and the nonlinear phase‐change phenomena, allowing for fine local approximations and the localized nonlinearity treatment by an algorithm we develop. These patches are identified via the solution of a representative mono‐domain transient thermal problem. The latter is also solved with our three‐level Arlequin method for comparison of the solutions and respective performances of both approaches. Moreover, two dimensional tests consisting in the creation of a 316 L stainless steel wall and a two AlSi10Mg layers, are carried out to further enlighten our global approach and to position it with respect to literature. [ABSTRACT FROM AUTHOR]

With the continuous research and development of amidoxime (AO)‐based adsorbents, industrialization production of uranium from seawater gradually becomes a reality. However, the currently available AO‐based adsorbents still suffer from low adsorption rate and poor selectivity. Herein, vertically aligned polyamioxime–graphene oxide (VA‐PG) sheet membrane is fabricated by directional freeze casting. The run‐through microchannels contribute to the free diffusion of uranyl ions (UO22+), leading to the fast adsorption kinetics. Furthermore, partially reduced graphene oxide allows high photothermal conversion efficiency and rapid in‐plane heat transfer, resulting in the fast temperature rise under simulated sunlight irradiation. Because of the endothermic behavior of UO22+, light‐irradiated VA‐PG can simultaneously satisfy the requirements of high adsorption capacity (13.63 mg‐U g‐Ads−1), high adsorption rate (0.43 mg g−1 day−1), and excellent selectivity toward U(VI) over V(V) (U/V = 1.24) in natural seawater, indicating the right direction for a breakthrough in the field of uranium extraction from seawater. [ABSTRACT FROM AUTHOR]

The turbulent convective thermal transfer in channel heat exchangers (CHEs) is studied numerically via the CFD (Computational Fluid Dynamics) method. Deflectors are inserted on the hot bottom walls of the heat channel to enhance the hydrothermal characteristics. Various shapes of in-line deflectors are considered, namely: rectangular (a/b = 0.00), cascaded rectangular-triangular (a/b = 0.25, 0.50, and 0.75), and triangular (a/b = 1.00) shapes. From the obtained results, the inclusion of in-line deflectors with a/b = 0.75 has given the most significant thermal enhancement factor, which was higher than that for a/b = 0.00, 0.25, 0.50, and 1.00 by about 5.36, 5.06, 67.27, and 3.88%, respectively. Also, the in-line cascaded deflector’ case (a/b = 0.75) shows an increase in the enhancement factor (η) from 4 to 15.44% over the cases of one deflector (corrugated, rectangular, triangular, trapezoidal, arc, (+), S, 45° V, 45° W, T, Γ, and ε-shaped) or two deflectors (staggered corrugated). This highlights the effectiveness of in-line cascaded rectangular-triangular deflectors with a/b = 0.75 in improving the performance of the proposed exchanger for the conditions adopted.

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The turbulent convective thermal transfer in channel heat exchangers (CHEs) is studied numerically via the CFD (Computational Fluid Dynamics) method. Deflectors are inserted on the hot bottom walls of the heat channel to enhance the hydrothermal characteristics. Various shapes of in-line deflectors are considered, namely: rectangular (a/b = 0.00), cascaded rectangular-triangular (a/b = 0.25, 0.50, and 0.75), and triangular (a/b = 1.00) shapes. From the obtained results, the inclusion of in-line deflectors with a/b = 0.75 has given the most significant thermal enhancement factor, which was higher than that for a/b = 0.00, 0.25, 0.50, and 1.00 by about 5.36, 5.06, 67.27, and 3.88%, respectively. Also, the in-line cascaded deflector' case (a/b = 0.75) shows an increase in the enhancement factor (η) from 4 to 15.44% over the cases of one deflector (corrugated, rectangular, triangular, trapezoidal, arc, (+), S, 45° V, 45° W, T, Γ, and ε-shaped) or two deflectors (staggered corrugated). This highlights the effectiveness of in-line cascaded rectangular-triangular deflectors with a/b = 0.75 in improving the performance of the proposed exchanger for the conditions adopted. [ABSTRACT FROM AUTHOR]

Abstract-In this study, an experimental measurement methodology is implemented that allows obtaining consistent temperature data during the turning operation of semi-hard C20 steel using SNMG carbide insert, allowing us to have better control at the tool-part interface. The interactions of the phenomena influencing the cut led our choices on the development of a correlation model for the analysis and prediction of the relationships between the machining parameters by measurement of the temperature. The measurement procedure implemented for the temperature estimate is based on the use of an FLIR A325sc type infrared camera mounted and protected by a device on the machine tool. The Taguchi method was chosen to find the relationships between the input factors (cutting speed (Vc), feed rate (a), depth of cut (p)), and the output factor (temperature (T)). In the future, we will develop a numerical validation model to simulate the machining process in order to predict temperatures. [ABSTRACT FROM AUTHOR]

The study of solar radiation in space has become something necessary, motivating the launch of radiometers on board satellites dedicated to perform total solar irradiance (TSI) measurements and to build a record of their behavior over the years, thus making these data essential for meteorology and climatology. In this study, we propose a simplified model to understand the thermal behavior of absolute radiometers, which are used in this type of measurement. The model considers the heat transfer among parts through conduction and loss only by radiation since the instrument operates in a space environment. The goal is to understand how each component interferes with sensitivity and response time of the instrument depending on its design, material, volume, and thermal contact. The model was applied to data generated by a prototype for validation. [ABSTRACT FROM AUTHOR]

Flat air solar collectors are used for heat transfer between the absorber and the heat transfer fluid, to improve this transfer there are several methods. Among these methods, the exchange surface lengthening and the creation of turbulence. In this work is done to give a comparison between two types of solar collectors, so we have made an improvement of Ben Slama Romdhane's solar collector by creating two air flow passages to increase heat transfer. We made a 3D simulation of a flat air solar collector with transverse baffles which causes turbulence and increases the exchange surface; we use the ANSYS calculation code to make the simulation and gives results with a brief time and minimal cost. [ABSTRACT FROM AUTHOR]

Objective: Laser irradiation is being used for treatment of peri-implantitis. Therefore, this study aimed to assess the heat transfer from laser irradiation on an implant-supported, metal-ceramic fixed prosthesis in vitro. Materials and methods: Two titanium implants were placed in artificial type I bone, and after abutment connection, a bridge was fabricated and cemented. A peri-implant 3-wall defect was created around one of the implants. Thermocouples were placed at coronal (T1/T2) and apical (T3/T4) positions of both implants, and the T5 thermocouple was placed in the pontic. An identical setup was created in the type IV artificial bone. Diode laser irradiation (2 W, noninitiated tips, 320μlm fiber, and noncontact) was performed for 60 sec on each experimental model. This experiment was performed separately with 810- and 980-nm lasers for pulsed and continuous modes. ΔT based on the baseline was recorded during irradiation. Statistical analysis was performed with repeated analysis of variance. Results: Across all experimental models, the recorded ΔT (°) values in T2, T4, and T5 at 10, 30, and 60 sec were significantly less than 10°C (p < 0.001) for both types of bones. For both types of bones, there was a statistically significant ΔT greater than 10°C (p < 0.001) for continuous and pulsed 980-nm irradiation and continuous 810-nm diode laser irradiation after 60 sec. For both 810- and 980-nm lasers, there was a statistically significant ΔT greater than 10°C (p < 0.001) for type I and IV bones under irradiation and only for the type I bone model under pulsed irradiation after 60 sec. Conclusions: Within the limitations of this study, 810- and 980-nm lasers on splinted implants placed in vitro may increase the temperature on adjacent splinted implants due to material conductivity and splinting. Clinicians are advised to keep the temperature lower than the critical threshold following recommended power settings to avoid excessive heat and control complications due to overheating. [ABSTRACT FROM AUTHOR]

Copyright of AmeSea International Journal is the property of Africa & Middle East Society for Education through Art 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.)

The microchannel heat sink is an effective technology for the thermal management of Li‐ion batteries. The overall performance of two heat sinks with improved thermal management of Li‐ion batteries was determined by a numerical simulation model. A manifold microchannel heat sink (MMC) and a traditional microchannel heat sink (TMC) with different aspect ratios of microchannels were developed. Thermal transfer performance and pressure drop characteristics of two heat sinks were compared by Fluent. Results indicate that the temperature uniformity of the TMC is worse than that of the MMC. The total pressure drop of TMC is significantly higher as compared to that of the MMC. Consequently, the MMC has a better overall performance than the TMC. [ABSTRACT FROM AUTHOR]

Wearable electronics are new structures with a wide range of possible applications. This study aims to analyze the effects of hot pressing in thermal transfer of different carbon-based composites as a new application method of screen-printed electronics on textiles. Flexible heaters were screen-printed on polyethylene terephthalate PET foil with composites based on graphene, carbon black, and graphite with different wt.%, measured and then hot pressed to measure and analyze differences. Research showed that the hot pressing process in thermal transfer resulted in decreased electrical resistance, increased power, and higher maximal temperatures. Best results were achieved with composites based on 12 wt.% graphene with sheet resistance lowered by about 40% and increased power by about 110%. This study shows promise for thermal transfer and screen-printing combination as an alternative for creating flexible electronics on textiles.

Copyright of German International Journal of Modern Science / Deutsche Internationale Zeitschrift für Zeitgenössische Wissenschaft is the property of Artmedia24 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.)

The steady flow of a nanofluid (mixture of titanium dioxide and water) in a rectangular channel under the influence of an inclined magnetic field is studied. The channel contains an upstream hot splitter plate in alignment with the upper and lower plates of the channel. It may be said that two incoming channel flows merge to form a single channel flow. This setup may apply to the heating chamber in which titanium dioxide can be used to enhance the thermal transfer rate. It is observed that the position of the splitter plate (that may act as an electric heater) affects the velocity and temperature of the fluid. Therefore, in order to ensure these facts, the examination of the flow behavior and the temperature distributions in the channel if the splitter is placed at different positions in the upstream have been probed. In addition, the effect of nanoparticles on the convection process has been probed. The streamlines are almost similar for a clear fluid as well as for a nanofluid (for low values of solid volume fraction of nanoparticles (i.e. φ < 0.05 )) for all values of the Reynolds number. However, the rise in the temperature is noted for the nanofluid if the concentration of nanoparticles is increased. The increase in the Reynolds number also supports the enhancement of the Nusselt number and, hence, the thermal transfer rate of the nanofluid. The Nusselt number is dominant in the vicinity of the trailing edge of the splitter because the trailing edge exhibits as a stagnation point. In addition, the maximum Nusselt number for nanofluid at moderate Reynolds number (e.g., Re = 100) is enhanced to 0.3% with respect to the clear fluid. Moreover, obtained results for this particular case are compared with the existing literature, and the results compare well. [ABSTRACT FROM AUTHOR]

The paper presents the modeling and simulation of heat transfer in ANSYS in a room of a house. The house is a three-room apartment located in Resita, Caras-Severin. The room where the heat transfer was studied is the coolest room in the apartment. The mathematical model of heat transfer was developed and then based on this mathematical model the numerical model with finite elements was elaborated, thus making possible the simulation of the thermal transfer in ANSYS. The results obtained can help the homeowner in the correct sizing of the heating system. [ABSTRACT FROM AUTHOR]

Copyright of Romanian Journal of Civil Engineering / Revista Română de Inginerie Civilă is the property of Matrix Rom 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.)

• A thermal and thermodynamic code aimed at describing the physics in LNG carrier tanks is developed. • Complex physical phenomena in LNG carrier tanks including ship motion are taken into account. • Operational Boil-off is simulated. This paper describes the numerical method implemented in Gaztransport & Technigaz specific-purpose thermal and thermodynamic code for complex physical phenomena in Liquefied Natural Gas (LNG) carrier tanks. The code is zero-dimensional and is used for LNG industrial applications and research activities in several fields related to Boil-off Gas (generation, consumption, optimization, etc.). The set of equations considered consists of the LNG and NG mass and energy conservation equations completed with equation of state and equations for LNG aging modeling. An explicit time-marching scheme with multiple-order methods is used. Specific effort has been put into the fast computation of the thermodynamic and transport properties of LNG. The implemented physical approaches have been validated by operational data. Better management of Boil-off represents a significant operational challenge for players in the LNG chain. Industrial applications illustrate important aspects of physical modeling such as saturation properties, thermal layer and sloshing. These examples also demonstrate the capability of the code to tackle a large variety of LNG carrier operating conditions and tank geometries. [ABSTRACT FROM AUTHOR]

Abstract We utilize thermal transfer technology to suggest a novel baking process for the emitting layer (EML) of residual-solvent-free organic light-emitting diodes (OLEDs). We deposited the EML onto an intermediate substrate using a conventional spin-coating process, after which the EML was transferred to the device by evaporating the EML through heating of the intermediate substrate. The EML films were fully transferred from an intermediate substrate to the target substrate at a temperature exceeding 350 °C under both a low vacuum of ∼10−3 Torr and a high vacuum of ∼10−6 Torr. The quantity of residual solvent was carefully investigated using gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) analysis methods. While residual solvent peaks were found to exist 1.69 min after the beginning of the measurement process in the conventional spin-coating EML films despite the baking condition of 150 °C, solvent peaks were not observed in the EML films created with the novel baking process under conditions identical to those used in the GC-MS measurement. Moreover, according to the NMR analysis, the solvent peak of toluene at 2.3 ppm was not found in the thermally transferred EML films. Furthermore, we investigated the device performance capabilities between samples fabricated using the conventional baking process and those created with the novel thermal transfer process. In spite of low pressure of ∼10−3 Torr, the current efficiency and the lifetime of the OLED device created via the thermal transfer process were enhanced owing to the elimination of the residual solvent. Graphical abstract Image 10778 Highlights • The quantity of residual solvent in emitting layer was carefully investigated using GC-MS and NMR analysis methods. • Through the conventional spin-coating and baking process, residual organic solvents could not be eliminated completely. • The residual solvent was not detected in the thermal transferred-EML film fabricated by our novel baking process. • Performance of OLED device created via the novel baking process was enhanced owing to the elimination of the residual solvent. [ABSTRACT FROM AUTHOR]