Search

AbstractThis study investigates the influence of heat flow due to a concentration gradient on unsteady Newtonian free convective magnetohydrodynamic heat and mass transform dissipative fluid flow over a heated normal porous plate in the presence of radiation absorption and chemical reaction. The plate temperature is assumed to fluctuate in a spanwise cosinusoidal manner over a time and exhibit heat generation with suction velocity. The analysis employs the multiple regular perturbation method to evaluate the governing equations under stipulated boundary conditions. The outcomes are visually depicted to assess the impact of various parameters on the system dynamics. Graphical representations illustrate the physical significance of various parameters on velocity, temperature, and concentration. Additionally, skin friction, mass transfer rate, and heat transfer coefficients are presented in tabular form. The significant findings indicate that velocity, temperature, and skin friction are directly proportional to parameters such as radiation absorption, heat generation, and heat flux due to a chemical potential gradient, whereas Sherwood and concentration are inversely proportional to the Schmidt number and chemical reaction. The outcomes obtained in this study have been cross-referenced with existing scientific literature, demonstrating strong concordance. This alignment provides confidence in the numerical results. [ABSTRACT FROM AUTHOR]

This article is concerned with the boundary layer formations over a deforming plane heated surface in a viscoelastic fluid having temperature-dependent physical properties. Viscoelastic fluid obeys a well-accepted Jeffrey fluid model that characterizes both relaxation and retardation times phenomena. Mathematical modeling is performed by considering exponential variations in viscosity, thermal conductivity, relaxation time, and retardation time with temperature. Transport equations are formulated under the aforesaid assumption and are solved for self-similar solutions using a numerical scheme. Solutions are utilized to generate streamlines and isotherms in both Newtonian and viscoelastic fluids. The momentum and thermal layers are specifically scrutinized for various controlling parameters. Illustrative results are included reflecting the consequences of variable physical properties on the induced viscoelastic fluid motion and accompanying heat transfer. In addition, skin friction factor for Jeffrey fluid with variable properties is evaluated and described. [ABSTRACT FROM AUTHOR]

An induced magnetic field is produced owing to an electric current flowing through the conductor. The induced magnetic field and the length of the conductor are in direct proportion. The current study examines the comparison of Yamada-Ota and Xue thermal conductivity models for a mixed convective hybrid nanoliquid flow through the permeable vertical channel influenced by an induced magnetic field. The projected model is supported by the combination of thermal radiation and heat generation and multiple slip conditions imposed on the walls. The Tiwari and Das model is adopted considering engine oil as a working liquid with immersed multiwalled and single-walled carbon nanotubes (CNTs) nanoparticles. The unique combination of strength, conductivity, and other properties make CNTs a promising material for an extensive variety of applications. These governing partial differential equations undergo conversion to ordinary differential equations via the similarity transformation and are then numerically processed with the bvp4c technique of the MATLAB program. The outcomes are deliberated logically via illustrations and tables. It is perceived that fluid velocity is compromised by strengthening the induced magnetic field. Nevertheless, an opposing trend is witnessed for the enhanced values of the Prandtl number. [ABSTRACT FROM AUTHOR]

AbstractIn the present investigation, the onset of Marangoni convection in the flow of self-rewetting fluid over a stretching disk has been discussed. The self-rewetting fluid is considered to be electrically conducting and the flow problem is discussed under the influence of an induced magnetic field. The fluid flow is mainly induced due to two different mechanisms: (i) onset of Marangoni convection due to presence of temperature gradient along the liquid-gas interface and (ii) induction of magnetic field due to presence of an external magnetic field, which modifies the original field. The governing partial differential equations are written, following Navier-stokes equations and Prandtl boundary layer equation. With the use of similarity transformations, the governing equations are turned into a system of ordinary differential equations. Nonlinear systems of ordinary differential equations are solved by the bvp4c technique. The reciprocal of the magnetic Prandtl number diminishes the induced magnetic profile. [ABSTRACT FROM AUTHOR]

The DTM-Pade approximation is used in the current work to analyze the thermal behavior and thermal stresses of an annular fin while accounting for temperature-dependent thermal conductivity and internal heat generation. The energy problem is converted into a nonlinear ordinary differential equation (ODE) using non-dimensional parameters, and the DTM-Pade approximation is then utilized to provide an approximate analytical solution. The impacts of various settings on the temperature field are also graphically analyzed. It has been found that increasing the heat generation parameter causes the temperature distribution to improve. The growing thermo-geometric parameter values lead to an improvement in fin efficiency. [ABSTRACT FROM AUTHOR]

The utilization of a ternary hybrid nanofluid, a recent development in the realm of nanofluids, can result in improved heat transfer. In the ongoing study, a ternary hybrid nanofluid flow is utilized, and it is carried out atop a porous spinning disc, which is exposed to a magnetic field, heat generation, thermal radiation, and Casson fluid. In this study, Blood/Water are taken as base fluids and (Ag–Au–Al2O3) are considered as a ternary hybrid nanoparticle. Nanoparticles made of gold and silver are put to use in a vast number of industries and fields, including nanotechnology and medicine. As a result of surface effects and quantum effects, these precious metals exhibit unique features in nanoform that play a vital role in with optical, magnetic, chemical, and mechanical behavior. Al2O3 unique optical, physical and biochemical qualities make it worthwhile for numerous uses, including nanophotonic, catalysis and the fabrication of high-energy composites. A set of relevant similarity transformations is used to generate non-dimensional forms of controlling paired nonlinear Partial Differential Equations (PDEs). MATLAB is used to perform a numerical solution with ODE45. In addition, the velocity outline decreases, and the temperature profile increases slightly before decreasing over a revolving disk when the values of magnetic parameters are increased. The distribution and radiant heat components heat up as the level gets higher. Aim and objectives of the study: The aim of this study is to analyze the Comprehensive Scrutinization of Ternary hybrid and Casson flow in a conducting porous rotating disk with internal heating. The primary objective of this analysis is to increase awareness of the impending energy crisis among those working in the industrial and technological sectors. Ternary nanoparticles (NPs) have a wide range of applications, which lends credence to the developed model. For example, Al2O3 can be used in a variety of ways that benefit society, it is used in water purification to remove water from the gas streams and extend people's lives. [ABSTRACT FROM AUTHOR]

In the present study, the thermal behavior of a longitudinal fin considering three types of heat transfer mechanisms (conduction, convection, and radiation) is investigated. For this research, thermal conductivity, heat source, and heat transfer coefficient are assumed nonindependent. A semianalytical scheme called the Galerkin Method is utilized for solving the dimensionless governing equation. The impacts of important physical variables like Peclet number, gradient of thermal conductivity, thermo‐geometric parameter, and radiation–conduction parameter on temperature profiles are analyzed comprehensively. The obtained results indicate that raising the thermo‐geometric parameter from 0 to 2 leads to a 32% reduction in the temperature profile. Also from the results, it can be found that a 28% increment in the temperature is observed by changing the gradient of thermal conductivity from 0 to 2. [ABSTRACT FROM AUTHOR]

In this paper, the investigation centered on examining a Maxwell fluid’s convective double diffusive flow carefully considers factors such as chemical reactions, radiation, and the presence of a permeable moving flat plate. Additionally, the study encompassed the effects of heat generation and magnetohydrodynamics (MHD). The governing equations, initially expressed as partial differential equations, were converted into ordinary differential equations using a similarity transformation technique to facilitate the analysis. The computational power of MATLAB’s BVP4C software was harnessed to solve this resultant system of ODEs efficiently. The outcomes of this investigation were presented in the form of graphical representations that vividly depicted the behavior of the flow field, energy conservation, and concentration profiles under various parameter combinations. The research findings were thoughtfully summarized in a table, offering a comprehensive overview of temperature, velocity, and mass profiles across various parameters. These parameters included the Deborah number, chemical reaction rate, Eckert number, Lewis number, Prandtl number, porosity parameter, and MHD parameter. A notable discovery emerging from this study was the inverse relationship observed between nondimensional concentration contours and the magnitude of the chemical reaction rate. Simultaneously, it was observed that higher values of the Maxwell fluid led to a rise in the thickness of the temperature boundary layer. These findings offer valuable insights into the intricate interplay of physical and chemical phenomena in convective flows involving complex fluid properties and boundary conditions. The temperature outline diminishes as the heat generation rate increases, while the concentration profile declines with an elevation in the chemical reaction rate. [ABSTRACT FROM AUTHOR]

[Objectives]To solve the current problems of large amount of agricultural waste, low resource utilization rate, and low temperature and insufficient CO2 for production of facility vegetables in cold winter areas in China, a shed type biomass fermentation device was designed. [Methods]This equipment included fermentation shed body(6 m long, 5 m wide, 2.8 m ridge height), forced heat exchange device and indoor heating pipeline in three parts. Using corn straw and sheep manure as raw materials for layered pile fermentation, the thermal performance of the fermentation unit brew, the impact on the thermal environment, gas environment and production of the facility greenhouse, and the economic benefits were explored. [Results]The temperature of the pile in the fermentation unit was above 50 ℃ for a total of 65 d, and the heat production efficiency reached 74.94%. The temperatures were more than 1.04 ℃ higher compared with the control greenhouse. The global warming potential(GWP)index decreased 96.98% through the gas filtration device and CO2 recovery system during the composting process. The CO2 concentration increased 2 270.58 mg·m-3. The soluble protein and vitamin C contents of tomatoes in the heated area were 24.6% and 29.2% higher than those in the control area respectively, and the lycopene was 71.3% higher than that in the control area. The operation of the biofermentation unit increased the field per plant by 5.99% and increased income by 8 712 yuan. [Conclusions]The application of shed-body biomass brew heaters in cold regions could provide heat and CO2 required for crop growth in facility greenhouses. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to analyze the Prandtl fluid flow in the presence of better mass diffusion and heat conduction models. By taking into account a linearly bidirectional stretchable sheet, flow is produced. Heat generation effect, thermal radiation, variable thermal conductivity, variable diffusion coefficient and Cattaneo–Christov double diffusion models are used to evaluate thermal and concentration diffusions. Design/methodology/approach: The governing partial differential equations (PDEs) have been made simpler using a boundary layer method. Strong nonlinear ordinary differential equations (ODEs) relate to appropriate non-dimensional similarity variables. The optimal homotopy analysis technique is used to develop solution. Findings: Graphs analyze the impact of many relevant factors on temperature and concentration. The physical parameters, such as mass and heat transfer rates at the wall and surface drag coefficients, are also displayed and explained. Originality/value: The reported work discusses the contribution of generalized flux models to note their impact on heat and mass transport. [ABSTRACT FROM AUTHOR]

The investigation focused on a Maxwell fluid's convective double diffusive flow, considering the influences of chemical reaction radiation on a permeable moving horizontal plate. Factors like heat generation, Newtonian heating conditions, and the effect of MHD were also included in this study. The governing equations, presented as partial differential equations, are then transformed into ordinary differential equations (ODEs) via similarity transformation approach. MATLAB's built-in software, BVP4C, was considered to solve the resulting system of ODEs. The obtained solutions were presented as graphical representations illustrating the flow field, energy conservation, and concentration behaviours for different parameter combinations. The targeted parameter here is to be taken as a Newtonian heating condition on the boundary, so the critical discovery from this study is the increase in nondimensional temperature contour and Nusselt number profile as the Newtonian heating effect value increased. The Sherwood number profile rose as the chemical reaction effect value increased. We have rigorously validated our work by comparing it to existing research, and the results have demonstrated a remarkably high degree of alignment. Consequently, we can confidently assert that our code is accurate and effectively aligned with this field's existing body of knowledge. This validation process reinforces the reliability and validity of our work, underlining its robustness and correctness. [ABSTRACT FROM AUTHOR]

AbstractIn this article, the behavior of the truncated conical shell subjected to thermomechanical loading in their inner and outer layers with internal heat generation source is investigated. The displacement field obeys kinematic of the first order shear deformation theory and the first-order temperature theory is used. Two-dimensional temperature analysis has been performed along the thickness and axis of the shell, which can be defined under various loading and thermomechanical boundary conditions. The set of governing equations is a system of differential equations with variable coefficients which are solved by using the analytical matched asymptotic expansion of the perturbations technique. The mentioned solution has little computational cost, therefore can be used well in parametric studies for optimization. It was shown, axial displacement is somehow independent of the radial axis and its maximum value occurs near the upper boundary. The conical shell has expanded in the radial direction. Also the maximum temperature happens approximately in the middle of the length of the conical shell. The parametric study showed, with the increase heat flux in the outer layer thereby expanding the area of heat application which would let more heat in than out. Also it was found, controlling the lifetime of the structure is the result of directing the cone angle. The results obtained from the analytical solution were compared with the Finite Element Method (FEM) analysis and the results of similar related articles, only to show a good agreement. [ABSTRACT FROM AUTHOR]

This work examines the Stefan blowing effect on the magnetized stagnation point flow of Prandtl–Eyring nanoliquid along a nonlinear elongating surface under the influence of numerous slips. In this study, the impressions of internal heat sources, nonlinearly varying radiation, activation energy with binary chemical reactions, viscous dissipation, and Joule dissipation are taken into account. The thermal flux associated with thermal radiation is computed using Rosseland's approximation for an optically thick environment. The controlling dimensional mathematical equations are transformed into nondimensional representations using appropriate similarity transmissions. Numerical temperature, velocity, and concentration solutions are obtained using a shooting method based on secant iteration and the Runge–Kutta–Fehlberg method. Using tabular and graphical displays of numerical data, the physical effects of a number of relevant parameters on the nanoliquid temperature, velocity, and concentration are examined. By contrasting the current results with information that has already been published for a few limiting circumstances, the validity of the acquired results is demonstrated. The effects of physical features on the local surface drag coefficient, rates of mass and heat transfer are demonstrated using numerical data shown in tabular form. For increasing values of the Stefan blowing parameter, fluid velocity decreased. The fluid temperature tends to rise as a result of thermal radiation. [ABSTRACT FROM AUTHOR]

Build simply – does a mechanical ventilation system in residential buildings save costs and energy? In Bad Aibling, three residential buildings were built in 2020 as research houses made of masonry, wood, and concrete, respectively. The complexity was reduced through simple construction and reduced building services: no mechanical ventilation; only presence‐controlled exhaust air from the interior bathroom was installed. The study addresses the question of whether it would have been better to install a mechanical ventilation system in the rooms. Four variants are compared: scenario A: natural (window) ventilation + bathroom exhaust air presence‐controlled (as built); scenario B: natural (window) ventilation + bathroom exhaust air presence‐controlled with basic ventilation; scenario C: single room heat recovery ventilator (SRHRV); scenario D: centralized ventilation (MVHR) (apartment unit) with heat recovery. The environmental impact and the costs of the respective ventilation systems caused by purchase, maintenance and operating energy over the life cycle were considered. Scenario A (as built) performs best in costs and global warming potential. Scenario C and D in particular would have to achieve high savings in heat demand in order to compensate for the negative environmental impact of the ventilation systems. In comparative measurements in practice, no corresponding savings effects could be determined. Mechanical ventilation is not suitable for improving the environmental impact or life cycle costs. [ABSTRACT FROM AUTHOR]

The analysis of non-Newtonian fluid flow over an oscillating surface often involves numerical simulations and experimental investigations. Computational fluid dynamics method including finite difference or finite element techniques can be used to crack the governing equations of the fluid flow. In this work, we used the Crank–Nicolson numerical technique to analyze the numerical behavior of unsteady boundary layer flow of Casson fluid with natural convection past an oscillating vertical plate. The temperature-dependent viscosity is assumed for the flow analysis. The impact of chemical reaction and heat generation coefficient is used to examine the mass and heat transferal rates. The investigation of non-Newtonian fluid flow over an oscillating surface is crucial for a wide range of industrial, biomedical, and scientific applications. The governing model of equations occurs in the form of nondimensional PDEs and then we use the dimensionless variables in order to achieve the dimensional PDEs. These equations are numerically solved by using the Crank–Nicolson technique. The Crank–Nicolson scheme is used because it has the ability to provide accurate and stable solutions and make it a valuable numerical technique in various scientific and engineering disciplines. The findings indicate the significance of numerous parameters on the mass, velocity and energy regions. The numerical outcomes of skin friction are observed due to fluid parameter, viscosity parameter, Grashof numbers of heat and solutal rates. [ABSTRACT FROM AUTHOR]

Friction stir welding (FSW), a solid‐state joining method, is an innovative technique widely employed in the welding of thermoplastics, with broad application areas such as the automotive and aerospace industries. Due to its inherent advantages, including ease of processing, biodegradability, and printability, polylactic acid (PLA) and its derivatives are notably the most commonly used polymers in 3D printing. The limited print area of 3D printers necessitates post‐production joining processes. In this study, the weldability of plates obtained using PLA Wood filament through the FSW is evaluated. For this purpose, different pin geometries (triangle, square, and screw), feed rates (20, 40, and 60 mm/min), and tool rotation speeds (1250, 1750, and 2250 rpm) are employed. Visual inspections are conducted to determine the effects of process parameters on weld quality and to identify defects in the weld region. Temperature values are measured to investigate the influence of heat generated during the FSW process. Furthermore, after determining the highest weld strengths achieved for each pin geometry, the weldability of PLA Wood material with PLA‐CF and PLA Plus materials is investigated using these parameters. The results indicate that the highest weld quality for joining PLA Wood plates is achieved using the square pin geometry, 20 mm/min feed rate, and 1750 rpm with an efficiency of 74.5%. When welding PLA Wood with PLA‐CF and PLA Plus, high weld strengths are obtained using the same process parameters (square pin, 20 mm/min, and 1750 rpm). Highlights: Friction stir welding process of 3D printed PLA Wood material.Friction stir welding process of dissimilar materials pairs.Effect of welding parameters on weld strength and hardness.Identifying the fracture surface images occurring in parts after friction stir welding.Examination of temperature generation during friction stir welding. [ABSTRACT FROM AUTHOR]

We analyze and quantify the amount of heat generated by a nanoparticle, injected in a background medium, while excited by incident electromagnetic waves. These nanoparticles are dispersive with electric permittivity following the Lorentz model. The purpose is to determine the quantity of heat generated extremely close to the nanoparticle (at a distance proportional to the radius of the nanoparticle). This study extends our previous results, derived in the 2D TM and TE regimes, to the full Maxwell system. We show that by exciting the medium with incident frequencies close to the plasmonic or Dielectric resonant frequencies, we can generate any desired amount of heat close to the injected nanoparticle while the amount of heat decreases away from it. These results offer a wide range of potential applications in the areas of photo-thermal therapy, drug delivery, and material science, to cite a few. To do so, we employ time-domain integral equations and asymptotic analysis techniques to study the corresponding mathematical model for heat generation. This model is given by the heat equation where the body source term comes from the modulus of the electric field generated by the used incident electromagnetic field. Therefore, we first analyze the dominant term of this electric field by studying the full Maxwell scattering problem in the presence of plasmonic or all-dielectric nanoparticles. As a second step, we analyze the propagation of this dominant electric field in the estimation of the heat potential. For both the electromagnetic and parabolic models, the presence of the nanoparticles is translated into the appearance of large scales in the contrasts for the heat-conductivity (for the parabolic model) and the permittivity (for the full Maxwell system) between the nanoparticle and its surroundings. [ABSTRACT FROM AUTHOR]

The thermal behavior of flooded lead–acid batteries with different distances between their electrodes, in which there takes place a temperature rise, was investigated at different rates of charging and discharging of these batteries with the use of the PIV method. It was established that, in the case of small rates of charging and discharging of such a battery, a decrease in the distance between its electrodes leads to a decrease in the temperature rise and in the heat generation in it, while, in the case where these rates are large, the opposite effects take place. [ABSTRACT FROM AUTHOR]

The nanofluids extensively contribute to cope the new heat transport challenges facing by the engineering systems and industries including paint, ceramics, chemical, aerodynamics, electronics, and medical sciences, etc. Thus, the innovations in new nanoliquid models can be disregarded in light of broad applications spectrum. Therefore, the current work concerns with the thermal process of hybrid nanoliquid by adding the important physical phenomenon. The flow of bionanofluid is taken inside a uniform expanding/contracting channel. To increase the model novelty, the significant influence of Lorentz forces, porous media, and heating source is added in the problem formulation. The resultant bionanofluid model is then analyzed via VIM (variational iteration method) and provided a deep discussion. It is inspected that unvarying expansion/contraction in the range of α = 1.0 , 2.0 , 3.0 , 4.0 and α = - 1.0 , - 2.0 , - 3.0 , - 4.0 , the bionanofluid attained maximum velocity about the central portion and in rest of the part it declines. However, due to increased viscosity of hybrid nanofluid, it reduced rapidly than conventional nanofluid. By increasing the permeability from 0.1 to 0.4, a rapid decrease in the fluid movement is observed. Further, the heat transmission progress reduced against the porous medium and Lorentz forces. The heat generation effects boosted the heating performance of the hybrid nanofluid. Moreover, the skin friction and heat transport rate are also discussed. [ABSTRACT FROM AUTHOR]

The reuse and recycling of rice husk waste help to reduce huge volumes of rice husk from milling industries and solve environmental challenges. In this study, the best mix ratio of rice husk briquette mixed with cassava starch for optimum heat generation was determined. It also determined the effect of clay paste on the heat generation property of the rice husk briquette. Rice husk briquettes with 0.15 – 0.20 cm s-1 flame propagation and density of 0.2041 – 0.2449 g cm-3 were used. Two sets of specimen were prepared. Specimen I was the rice husk – cassava starch mixture. It was mixed at the mixing ratios of 90:10, 80:20, 70:30, 60:40, and 50:50. Specimen II, which was rice husk – cassava starch – clay paste mixture, was mixed at the mixing ratios of 90:8:2, 80:16:4, 70:24:6, 60:32:8, and 50:40:10. The response of heat generation to the mix ratio changes and effect of clay paste on heat generation property were determined. The findings of the study indicate that an increase of the proportion of cassava starch in the rice husk briquette increases heat generation but reduces longevity of the rice husk briquette. The optimum heat generation mix ratio was identified to be 80:20, since it takes the minimum time (6 minutes) to reach the boiling point of water without total extinction of the briquette. Clay paste additive increases heat generation and longevity of rice husk briquette. A 20% clay paste replacement of cassava starch reduces the boiling time of the water by 1 minute for the 80:20 mix ratios. Clay paste has potential to be used as an additive in the production of briquettes for increased heat generation and longevity. The findings of the study could find application in the waste reuse and recycling industries. [ABSTRACT FROM AUTHOR]

• Effects of temperature and moisture content on MSW heat generation were studied. • Maximum heat generation occurred at an initial temperature of about 40 °C. • A simple formula for calculating heat generation by MSW degradation was proposed. Heat generation from degradation of organic matter in municipal solid waste (MSW) often leads to increased landfill temperature. However, it is difficult to measure environmental heat loss in laboratory and field tests; therefore, little research has been conducted to evaluate heat generation during waste degradation under different initial temperatures and moisture contents. In this study, tests were conducted to investigate the effects of initial temperature and moisture content on heat generation during waste degradation. A simple formula for calculating heat generation was proposed. Within 200 h, the waste temperature decreased by about 70%, and lower initial moisture contents were associated with greater temperature decreases. The smallest temperature decrease of 47% and the greatest heat generation occurred when the initial temperature was 40 °C. The initial moisture content increased from 30% to 60% and the heat generation increased from 5% to 36%. The heat generation per unit mass of organic matter during the aerobic and anaerobic stages were 19.44–23.77 and 0.27–0.50 MJ·kg−1, respectively, indicating that the proposed formula for calculation of heat generated from waste degradation was reasonable. The results presented herein provide theoretical support for the prediction of heat generation and the recycling of heat resources in MSW landfill sites. [ABSTRACT FROM AUTHOR]

In this work, a facile solvothermal synthesis of MnFe2O4 nanoparticles is followed by an easy and reproducible process to envelop the synthesized MnFe2O4 nanoparticles with iron oxide nanoparticles using ethanol and ethylene glycol as solvents. All prepared MnFe2O4 nanoparticles show a homogenous distribution of spherical particles with an average particle size between 12 and 16 nm. The encapsulation process of MnFe2O4 nanoparticles does not affect their homogenous distribution with a very thin layer of Fe3O4 on the shell structure. The magnetic properties showed a superparamagnetic character with enhanced magnetic properties of MnFe2O4@Fe3O4 compared to pure MnFe2O4, which has been verified by magnetization and electron spin resonance. The heating efficiency of the prepared samples was evaluated in terms of the specific loss power using the calorimetric method. The synthesized MnFe2O4 nanoparticles show a significantly high value of about 72 W/g, which got doubled in the core@shell structure and reached 140 W/g at 189 kHz and 10kA/m of the magnetic field. [ABSTRACT FROM AUTHOR]

The main theme of this research is to deliberate the irreversibility aspects of spinning nanofluid (PEG-H2O / ZrO2) and hybrid (PEG-H2O / ZrO2–MgO) nanofluid towards a movable sheet. Here a mixture of polyethylene glycol and water is utilised as a continuous phase fluid. Two different nanoparticles are considered, i.e., zirconium dioxide (ZrO2) and magnesium oxide (MgO). The heat transfer behaviour is examined and modelled subject to viscous dissipation, heat source and heat flux. Furthermore, the entropy generation problem is addressed by the second law of thermodynamics. Nonlinear dimensionless differential systems are developed by suitable variables. The given dimensionless systems are solved using numerical techniques (ND-solve method). Effects of influential variables on fluid flow, temperature, Bejan number and entropy rate for both PEG-H2O / ZrO2 and PEG-H2O / ZrO2–MgO fluids are graphically examined. A higher approximation of volume fractions rises the velocity profile, while reverse impact is seen for the Bejan number. An increment in rotation variable corresponds to increased velocity. A similar scenario is seen for the thermal field and entropy rate through the radiation effect. An opposite impact is seen for the Bejan number and entropy rate through the Brinkman number. An augmentation in temperature is seen for the Eckert number. Furthermore, we noticed that heat transport in a hybrid nanofluid (PEG-H2O / ZrO2–MgO) is higher than that for the nanofluid (PEG-H2O / ZrO2). [ABSTRACT FROM AUTHOR]

This present study involves examining the nature of 3D rotational MHD nanofluid flow through a stretching sheet. Alumina Al 2 O 3 –ethylene glycol C 2 H 6 O 2 -based nanofluid is considered in this investigation. A normal magnetic field acts on the sheet. Radiative thermal boundary condition with slip velocity has been considered. Suitable similarity transformation is used to derive a system of ordinary differential equations. The spectral quasilinearisation method (SQLM) is applied to solve this system. For curiosity, the skin friction coefficient and Nusselt number have been calculated. Due to effective heat generation and heat radiation, a significant temperature difference is produced. Besides, the impact of the variation in the volume fraction of nanoparticles is remarkable. The influence of key parameters has also been shown graphically. The graphical representation shows that the magnetic parameter declines in the radial velocity component, while the layout of the tangential component of velocity enhances in the form of a parabola with an enhancement of the magnetic parameter. Temperature layout is enhanced with the increasing values of the magnetic parameter, nanoparticle volume fraction, temperature ratio parameter, radiation parameter and Biot number. The generation of entropy enhances with the increase in the magnetic parameter, Brinkman number and Reynolds number, while nanoparticle volume fraction and temperature difference parameters decrease the entropy generation. For the engineering interest, the skin friction coefficient along the x-axis, y-axis and the local Nusselt number have also been calculated. The impacts of pertinent parameters on the skin friction coefficient along the x-axis, y-axis and the local Nusselt number are scrutinised numerically. We have compared our current result with the available studies for special cases ϕ = 0 , M = 0 and found that the results are in good agreement. [ABSTRACT FROM AUTHOR]

The work-hardening and low thermal conductivity characteristics of SS304 had always been a challenge to machine it easily with better tool life and surface finish. The type of coolant, its temperature and surface coated inserts plays a pivotal role in machining the hard materials. A number of experiments were performed with a TiCN and tungsten carbide inserts in combination with soluble/synthetic coolant at ambient temperature and at 0oC TiCN-coated cemented carbide insert with synthetic coolant at 0°C is recommended for machining as per the results obtained through this research work. It was found that TiCN-coated inserts used for machining SS304 with synthetic coolant at 0°C provide better tool life, less tool wear, improved surface finish and low heat generation. The tool life was enhanced approximately by 75%, 20% reduction in maximum temperature generation and 50% improvement in surface finish of workpiece. [ABSTRACT FROM AUTHOR]

Abstract This study reveals the impact of heat generation and variable strength of rotation on the unsteady flow of a hybrid nanofluid over a rotatable disk with stretching characteristics and deceleration. A novel mathematical model specifically tailored to elucidate the behavior of a hybrid nanofluid is proposed. By employing similarity variables, the governing model is reformulated into ordinary differential equations (ODEs). The bvp4c function (MATLAB) is employed to efficiently obtain the numerical solutions of these ODEs. To provide a comprehensive study, a stability analysis is also conducted to investigate the properties associated with the non-unique dual solutions generated by the model. Dual solutions are generated, and both are analyzed to be stable. A lower amount of heat generation with greater disk rotation strength is recommended to further improve the heat transfer rate of the model. The bifurcation point is absent within the setup ranges of the parameters in the present study, which suggests a well-maintained laminar flow simulation. The findings of this study offer valuable insights and can assist other researchers in improving their understanding and modeling of similar fluid flow systems, particularly hybrid nanofluid flow systems. [ABSTRACT FROM AUTHOR]

Abstract The present study analyses the magnetohydrodynamics (MHD) viscous nanofluid flow past a nonlinearly stretching sheet embedded in a porous medium under the influence of heat generation and thermal radiation. Further, variable magnetic field as well as variable permeability is used instead of constant magnetic field and permeability due to many therapeutic applications, which makes them distinctive and practically helpful. The MHD viscous flow and heat transfer equations have been generated as coupled second-order nonlinear partial differential equations using a mathematical model that resembles the physical flow problem. The partial differential equations governing the flow problems are reduced to ordinary differential equations via similarity variables. The reduced equations are then solved by Runge–Kutta–Fehlberg’s scheme with shooting method by the help of MATLAB software. The result obtained reveals that enhancing the heat generation parameter, porosity parameter, and radiation parameter upsurges the temperature of the nanofluid, whereas the magnetic parameter shows the reverse effect in the case of velocity distribution. Nusselt number N u x decreases at the rate of 2.6147% for copper–water nanofluid when ϕ increased from 0 to 0.05. Silver nanoparticles have the highest heat transfer as compared to other nanoparticles. Because of this, silver nanoparticles are the most effective thermal conductors for increasing the effectiveness of heat storage in phase transition materials. [ABSTRACT FROM AUTHOR]

The combined effects of diffusion-thermo and radiative absorption on free convective hydromagnetic heat-generating chemically reactive flow of Cu-water nanofluid past an instantaneously accelerated unlimited vertical plate nested in a porous medium are investigated. A comparative analysis is executed for both isothermal and ramped conditions. The set of transformed domain equations has been obtained using a closed form of the Laplace transform method with the help of the Heaviside step function. Graphical and tabular explanations are provided for the physical characteristics of several flow parameters affecting the problem. Graphs are generated using MATLAB computing software. Findings of the problem manifest that the diffusion-thermo parameter and the radiation absorption parameter intensify the velocity and fluid temperature in the entire fluid area. This augmentation is most prominent for copper nanoparticles. Concentration, temperature, and velocity profiles in the case of ramped conditions are less than in isothermal conditions. Furthermore, the ramped parameter amplifies the heat transfer rate while reversing the mass transfer rate. It is also established that the volume concentration of nanoparticles enhances the heat transfer rate. The present study is of great interest in numerous fields of industry and machine-building applications. [ABSTRACT FROM AUTHOR]

This manuscript provides a comprehensive analysis of the characteristics of unavoidable thermal effects in solid-state lasers and an end-to-end solution for the heat generated inside the gain medium. After a description of the basic physical mechanisms (Quantum defect, Upconversion, and Thermal Quenching of Fluorescence), Total Heat Generation Coefficient is calculated for suitable holder designed used in the practical operating conditions of a cavity to reduce the thermal effects and to increase lasing efficiency. In particular, simulations that have been performed with a finite-element model is used to theoretically simulate thermal lensing in Cr:Nd:GSGG crystals with pumping scenarios. The predicted values for thermally induced strengths are compared with experimentally observed previous results. Finally, necessary calculations for the new crystal holder design were made by the help of the simulation modelling for a 1.5 W Gaussian (TEM00) laser diode double-end-pumped slab geometry Cr:Nd:GSGG crystal. The results were discussed deeply, and it is proven that the new holder design for this gain medium is suitable. [ABSTRACT FROM AUTHOR]

Heat transmission processes have numerous industrial applications. A novel form of nanofluid known as the hybrid nanofluid that has a higher thermal exponent helps in improving the ability of regular fluids to transfer heat. This article aims to analyze the impact of hybrid nanofluid with effects like magnetohydrodynamics (MHD), Brownian motion and thermophoresis, heat generation/absorption, and chemical reaction past a permeable moving thin needle. Two assorted nanomaterials (MoS2 and Fe3O4) are added in a base fluid such as ethylene glycol (EG) to access the performance of the hybrid nanofluid. Using suitable similarity variables, the governing equations of the problem are turned into customary ordinary differential equations. The resulting equations are solved analytically using the Galerkin method (GM) and dual solutions are obtained in a certain range of moving parameter λ. Due to this, a stability test is implemented to find a stable solution. With the help of a bvp4c function in Matlab software, the smallest eigenvalues are computed, where positive eigenvalues are linked with the stable solution while negative eigenvalues are linked with the unstable solution. It is concluded that only the first solution is stable while the second solution is not. The skin friction factor and heat transfer rate are reduced by growing the needle size. The magnetic field has an inverse relation with the flow field and direct relation with the temperature field. The improvement in heat generation parameter causes the fluid temperature to rise. The fluid concentration is enhanced with the increment of the chemical reaction parameter. [ABSTRACT FROM AUTHOR]

The numerical analysis is conducted to evaluate the heat generating as well as Soret–Dufour influences on magnetohydrodynamic unsteady chemically reacting fluid. It is owing to an exponentially stimulating perpendicular porous plate entrenched in the absorbent medium by considering ramped surface temperatures and concentrations in the endurance of thermal radiating. The fundamental governing set of equations of the fluid dynamics in the flow is converted into dimensionless form by inserting suitable dimensionless parameters and variables, and the resulting equations are numerically solved by the efficient Crank–Nicolson implicit finite difference method. The influence of several important substantial parameters into the model on the velocity, temperature, and concentration of the fluid, in addition to the skin‐frictions coefficient, Nusselt's number along with Sherwood's number for both thermal conditions has been studied and explored intensely by making use of graphs and tables. It is discovered that, with mounting values of Dufour, heat generating as well as thermal radiating parameters, the fluid temperatures, and velocity enhanced. Likewise, it is noticed that increasing the Soret parameter causes escalated fluid velocity and concentration, whereas the reverse result is noted with the chemical reaction parameter. [ABSTRACT FROM AUTHOR]

The generalized magnetohydrodynamics (MHD) free convection flow of a Casson fluid through a channel immersed in a porous media with mass and heat transfer is considered. With heat generation, the contribution of concentration gradient is taken into account for heat flux (Dufour effect), and chemical reaction of order first for species balance is also considered. Initially, governing equations of flow model are reduced to nondimensional equations and then solved analytically. The transformed solutions for concentration, temperature, and velocity are written in summation form to invert by Laplace transform easily. The closed form solution of field variables has been plotted graphically due to different parametric variations to analyze the behavior of concentration, temperature, and flow fields against the physical parameters. Furthermore, comparisons among fractionalized and ordinary concentration, temperature, and velocity fields are made to see the effect of parameter α. It is concluded that concentration, temperature, and velocity obtained with fractional derivative are smaller than that obtained by ordinary derivative. Therefore, fractional derivative is the best choice to obtain controlled concentration, temperature, and velocity. [ABSTRACT FROM AUTHOR]

A convective‐radiative fully wet porous inclined longitudinal fin of exponential profile is the focus of the current work. The thermal behavior of the fin under unsteady conditions has been analyzed for adiabatic and convective boundary conditions. The exponential fin and its counterpart inverted exponential fin are simultaneously investigated by considering temperature‐relevant thermal conductivity and heat generation. The modeled governing equation upon nondimensionalization reduces to a partial differential equation which is computed by employing the finite difference approach. The impact of relevant parameters like the convective parameter, radiative parameter, wet porous parameter, dimensionless time, exponential index, dimensionless ambient temperature, generation number, thermal conductivity parameter, and angle of inclination on thermal characteristics of exponential and inverted exponential fin structures with adiabatic and convective boundary restrictions have been examined. One of the main outcomes was that the inverted exponential fin with an adiabatic tip gives rise to the highest thermal curve, and the tapered exponential fin with a convective tip resulted in the lowest thermal curve. [ABSTRACT FROM AUTHOR]

Exploration related to chemical processes in nanomaterial flows contains astonishing features. Nanoparticles have unique physical and chemical properties, so they are continuously used in almost every field of nanotechnology and nanoscience. The motive behind this article is to investigate the Cross nanofluid model along with its chemical processes via auto catalysts, inclined magnetic field phenomena, heat generation, Brownian movement, and thermophoresis phenomena over a symmetric shrinking (stretching) wedge. The transport of heat via nonuniform heat sources/sinks, the impact of thermophoretic diffusion, and Brownian motion are considered. The Buongiorno nanofluid model is used to investigate the impact of nanofluids on fluid flow. Modeled PDEs are transformed into ODEs by utilizing similarity variables and handling dimensionless ODEs numerically with the adoption of MATLAB's developed bvp4c technique. This software performs a finite difference method that uses the collocation method with a three-stage LobattoIIIA strategy. Obtained outcomes are strictly for the case of a symmetric wedge. The velocity field lessens due to amplification in the magneto field variable. Fluid temperature is amplified through the enhancement of Brownian diffusion and the concentration field improves under magnification in a homogeneous reaction effect. [ABSTRACT FROM AUTHOR]

This paper investigates the thermal-pseudo mechanical (TPM) model's residual stress prediction capability for its utility in developing friction stir processing (FSP). Specifically, two FSP tests under different processing conditions were conducted, and the corresponding simulations were carried out to verify if the TPM model can predict residual stresses for various tool radii and workpiece materials. The model successfully predicted residual stresses with an error less than 4% for one of the tests but failed to work for the other test. Further simulations under different FSP conditions proved that the TPM model works for cast aluminum alloys and wrought aluminum alloys. In addition, the large FSP tool used was found to be the reason for the model's failure on one of the tests. This indicates that there is a range of tool radii for which the TPM model is applicable. As a solution, this paper suggests modifications to the TPM model based on calibration to the FSP test temperatures. The resulting residual stress prediction is accurate and differs from the experimentally characterized stress values by only 6.5 MPa. The calibrated TPM model requires FSP to be carried out when using a tool with a different radius. Following that, the effect on residual stresses due to changes in the other process parameters, such as the tool traverse & rotation speeds and the clamping conditions, can be predicted. [ABSTRACT FROM AUTHOR]

An efficient computational approach is presented to solve numerically a mathematical model of fractional order in a fluid. The proposed model describes the effects of variable heat flux, viscous dissipation, and the slip velocity on the viscous Casson flow and heat transfer due to an unsteady stretching sheet taking into account the influence of heat generation or absorption. A collocation method based on a summation of Mittag–Leffler functions is employed to convert the system of ODEs that describe the problem to a system of algebraic equations. This system is constructed as a constrained optimization problem and optimized to get the unknown coefficients. Error analysis of the approximation solution is studied. The influence of the parameters governing the flow and heat transfer such as unsteadiness parameter, slip velocity parameter, Casson parameter, local Eckert number, heat generation parameter, and the Prandtl number are discussed and presented through tables and graphs. Besides, the local skin‐friction coefficient and the local Nusselt number at the stretching sheet are computed and discussed. Finally, the results show that the given procedure is an easy and efficient tool to investigate the solution of such fluid models. [ABSTRACT FROM AUTHOR]

Introduction: Heat is generated and transferred to the dentine-pulp complex during various dental procedures, such as from friction during cavity preparations, exothermic reactions during the polymerisation of restorative materials and when polishing restorations. For in vitro studies, detrimental effects are possible when intra-pulpal temperature increases by more than 5.5°C (that is, the intra-pulpal temperature exceeds 42.4°C). This excessive heat transfer results in inflammation and necrosis of the pulp. Despite numerous studies stating the importance of heat transfer and control during dental procedures, there are limited studies that have quantified the significance. Past studies incorporated an experimental setup where a thermocouple is placed inside the pulp of an extracted human tooth and connected to an electronic digital thermometer. Methods: This review identified the opportunity for future research and develop both the understanding of various influencing factors on heat generation and the different sensor systems to measure the intrapulpal temperature. Conclusion: Various steps of dental restorative procedures have the potential to generate considerable amounts of heat which can permanently damage the pulp, leading to pulp necrosis, discoloration of the tooth and eventually tooth loss. Thus, measures should be undertaken to limit pulp irritation and injury during procedures. This review highlighted the gap for future research and a need for an experimental setup which can simulate pulp blood flow, temperature, intraoral temperature and intraoral humidity to accurately simulate the intraoral conditions and record temperature changes during various dental procedures. [ABSTRACT FROM AUTHOR]

Semi-solid lithium slurry battery is an important development direction of lithium battery. It combines the advantages of traditional lithium-ion battery with high energy density and the flexibility and expandability of liquid flow battery, and has unique application advantages in the field of energy storage. In this study, the thermal stability of semi-solid lithium slurry battery material system was investigated for the first time employing C80 micro-calorimeter. In this new electrode material system, the heat generation of the electrolyte is the decisive factor for its thermal stability. Then, the measurement of in-situ dynamic cycle heat generation of semi-solid lithium slurry battery indicated a lower heat generation than traditional lithium-ion battery. What's more commendable is that its electrochemical performance is basically the same as traditional lithium-ion battery. In addition, through the HPPC test, the mechanism of semi-solid lithium slurry battery cycle heat generation was explained. So, in this work, a preliminary evaluation on the safety and cycling stability of semi-solid lithium slurry battery is carried out. The electrochemical performance test affirms the application prospects of semi-solid lithium slurry battery, and the evaluation on the fire safety provides a reference for the future industrial applications of semi-solid lithium slurry battery. [ABSTRACT FROM AUTHOR]

In recent years, there has been a significant increase in interest in the use of curdlan, a naturally derived polymer, for medical applications. However, it is relatively inactive, and additives increasing its biomedical potential are required; for example, antibacterial compounds, magnetic particles, or hemostatic agents. The stability of such complex constructs may be increased by additional functional networks, for instance, polycatecholamines. The article presents the production and characterization of functional hydrogels based on curdlan enriched with Fe3O4 nanoparticles (NPs) or Fe3O4–based heterostructures and poly(L-DOPA) (PLD). Some of the prepared modified hydrogels were nontoxic, relatively hemocompatible, and showed high antibacterial potential and the ability to convert energy with heat generation. Therefore, the proposed hydrogels may have potential applications in temperature-controlled regenerative processes as well as in oncology therapies as a matrix of increased functionality for multiple medical purposes. The presence of PLD in the curdlan hydrogel network reduced the release of the NPs but slightly increased the hydrogel's hemolytic properties. This should be taken into account during the selection of the final hydrogel application. [ABSTRACT FROM AUTHOR]

Numerical investigation of combined laminar natural-convection and volumetric radiation with internal heat generation is presented in this paper and computations are performed for a grey gas-filled square cavity whose horizontal walls are adiabatic and vertical walls are differentially heated. The convection is treated under Boussinesq approximation by an approach based on finite-volumes and the volumetric radiation by the discrete ordinates method. Flow and heat transfer characteristics through isotherms, streamlines, and average Nusselt numbers have been presented for an external Rayleigh number 106, internal Rayleigh number 0 to 4 · 1012, optical thickness 0 to 10, and albedo 0 to 1. Representative results illustrating the effects of the optical thickness and the internal heat generation on the flow and the temperature distribution within the cavity are presented. The results reveal that the fluid-flow and heat transfer are influenced significantly by the volumetric radiation and the internal heat generation. By comparing the solutions in pure convection, the results in combined convection-volumetric radiation show that when the medium is participating, the effect of internal source presence is very important. [ABSTRACT FROM AUTHOR]

The study of reversible and irreversible heat generation of lithium-ion batteries at different C rates is important for designing thermal management system. Galvanostatic intermittent titration technique is used to determine the overpotential of different SOC (state of charge) or SOD (state of discharge) of commercial lithium iron phosphate pouch cells. The reversible and irreversible heat generation of the battery is calculated based on the entropy change and overpotential. It is found that when the lithium iron phosphate battery is charged, reversible heat first manifests itself as heat absorption, and then soon as exotherm after around 30% SOC, while the reverse for discharge. The total heat generation of lithium iron phosphate batteries during charging is higher than that during discharging. The relative contribution of irreversible and reversible heat generation at low and high rates are different. At 0.1 C rate, the maximum proportion of qrev is about 70%, while at 1 C rate, the maximum proportion of qrev is about 25%. [ABSTRACT FROM AUTHOR]

The current scrutinization concentrated on the consequences of viscous dissipation and chemical reaction on unsteady MHD two‐dimensional free convective fluid flow past a semi‐infinite inclined permeable plate with radiation absorption and heat generation. The governing equations are determined analytically by employing the perturbation technique. The impact of various physical estimators on velocity, temperature, concentration, skin friction, and Nusselt number along with Sherwood number were exemplified quantitatively through graphs. It was concluded that velocity declined with the incremental values of Eckert number, but contradictory impact occurred in the case of skin friction. In addition temperature, Nusselt number, as well as velocity, declined with the progressive values of radiation absorption. However, skin friction was accelerated with the augmented values of radiation absorption. Velocity accelerated, with the progressive values of angle of inclination. Concentration declined with the various augmentation values of chemical reaction as well as Schmidt number. [ABSTRACT FROM AUTHOR]

The control of desired product quality attributes in the crystallization process is one of the major concerns of the pharmaceutical industries due to the established standard limits for active pharmaceutical ingredients in applications. The objective of the present work is to establish the fundamental understanding and methodology of the batch cooling sonocrystallization process to tune the crystal attributes over the range of operating parameters, i.e., ultrasound amplitude, duration of sonication, and cooling rate. For the constant cooling rate, the effect of three levels of ultrasound amplitude has been investigated over the range of durations of insonation. It is observed for a fixed cooling rate that the optimized set of ultrasound parameters shortens the induction time resulting in a finer range of particles increasing the surface area and narrowing the particle size distribution. The performance of the process in terms of thermal characteristics has been analyzed to delineate the effect of operating parameters to be employed as a function of the product characteristics. The simple expressions for temperature profiles during the process have been proposed as a function of saturation temperature to facilitate their applications in the optimization of the operating parameters for the desired product size and size range. [ABSTRACT FROM AUTHOR]

A study of hybrid-nanofluid flow induced by the uniform rotation of a circular porous disk is presented for the purpose of facilitating the heat transfer rate. The Hall and Ohmic heating effects resulting from an applied magnetic field and the source of heat generation/absorption are also considered to see their impact on flow behavior and enhancing the heat transfer rate. The physical problem under the given configuration is reduced to a set of nonlinear partial differential equations using the conservation laws. Similarity transformations are adopted to obtain a system of ordinary differential equations which are further solved using the Shooting Method. Results are presented via graphs and tables thereby analyzing the heat transfer mechanism against different variations of physical parameters. Outcomes indicate that the wall suction plays a vital role in determining the behavior of different parameters on the velocity components. It is notable that the wall suction results in a considerable reduction in all the velocity components. The enhanced Hartman number yields a growth in the radial velocity and a decay in the axial velocity. Moreover, consequences of all parametric effects on the temperature largely depend upon the heat generation/absorption. [ABSTRACT FROM AUTHOR]

We have examined the magnetized stagnation point flow of non-Newtonian fluid towards an inclined cylindrical surface. The mixed convection, thermal radiation, viscous dissipation, heat generation, first-order chemical reaction, and temperature-dependent thermal conductivity are the physical effects being carried for better novelty. Mathematical equations are constructed for four different flow regimes. The shooting method is used to evaluate the heat transfer coefficient at the cylindrical surface with and without heat generation/thermal radiation effects. For better examination, we have constructed artificial neural networking models with the aid of the Levenberg–Marquardt training technique and Purelin and Tan-Sig transfer functions. The Nusselt number strength is greater for fluctuations in the Casson fluid parameter, Prandtl number, heat generation, curvature, and Eckert number when thermal radiations are present. [ABSTRACT FROM AUTHOR]

Rubber composites are extensively used in industrial applications for their exceptional elasticity. The fatigue temperature rise occurs during operation, resulting in a serious decline in performance. Reducing heat generation of the composites during cyclic loading will help to avoid substantial overheating that most likely results in the degradation of materials. Herein, we discuss the two main reasons for heat generation, including viscoelasticity and friction. Influencing factors of heat generation are highlighted, including the Payne effect, Mullins effect, interface interaction, crosslink density, bond rubber content, and fillers. Besides, theoretical models to predict the temperature rise are also analyzed. This work provides a promising way to achieve advanced rubber composites with high performance in the future. [ABSTRACT FROM AUTHOR]

Build simply – does a ventilation system save you money and energy? In Bad Aibling, three residential buildings were built in 2020 as research houses made of masonry, wood and concrete. The complexity was reduced through simple construction and reduced building technology. There was no room ventilation. Only presence‐controlled exhaust air from the interior bathrooms was installed. The study addresses the question of whether it would have been better to install a living space ventilation system in the research buildings. Four variants are compared: scenario A: window ventilation +bathroom exhaust air presence‐controlled (as built); scenario B: window ventilation +bathroom exhaust air presence‐controlled with basic ventilation; scenario C: decentralized individual room fans with heat recovery; scenario D: central apartment unit with heat recovery. The environmental impact and the costs of the respective ventilation systems caused by the use of technology, maintenance and operating energy over the life cycle were considered. Scenario A (as built) performs best in the examined dimensions of costs and global warming potential. Variants C and D in particular would have to achieve high savings in heating requirements in order to compensate for the negative environmental impact of the living space ventilation systems. In comparative measurements in practice, no corresponding savings effects could be determined. Mechanical domestic ventilation is not suitable for improving the environmental impact or life cycle costs of the project. [ABSTRACT FROM AUTHOR]

Data sets of internal resistances and open-circuit voltage of a particular battery are needed in ANSYS Fluent program to predict the heat generation accurately. However, one set of available data, called Chen's original, does not cover all types and shapes of batteries. Therefore, this research was intended to study the effects of shapes and polarization chemistries on heat generation in Li-ion batteries. Two kinds of material chemistries (nickel manganese cobalt oxide, NMC, and lithium iron phosphate, LFP) and three forms (cylindrical, pouch, and prismatic) were studied and validated with the experiment. Internal resistance was unique to each cell battery. Differences in shapes affected the magnitude of internal resistance, affecting the amount of heat generation. Pouch and prismatic cells had lower internal resistance than cylindrical cells. This may be the result of the forming pattern, in which the anode, cathode, and separator are rolled up, making electrons difficult to move. In contrast, the pouch and prismatic cells are formed as sandwich layers, resulting in electrons moving easily and lowering the internal resistance. The shapes and chemistries did not impact the entropy change. All batteries displayed exothermic behavior during a lower SOC that gradually became endothermic behavior at around 0.4 SOC onwards. [ABSTRACT FROM AUTHOR]

In this study, the plane thermoelastic frictional contact problem between a magneto-electro-elastic (MEE) layer and a rigid cylindrical or flat punch is discussed. Punches are assumed to be perfect electromagnetic and thermal insulators; they slide over the layer with a small constant speed, and due to the friction, heat flux occurs. The general stress, displacement, and electromagnetic expressions for the contact problem are derived using the theory of thermoelasticity. Applying the boundary conditions, the contact problem is reduced to a Cauchy-type singular integral equation, which is then solved numerically using the Gauss-Jacobi integration formula. [ABSTRACT FROM AUTHOR]

Thermoset composites are strong candidates for large-scale material extrusion additive manufacturing (AM). However, uncured thermoset composites become unstable as print height increases. Here, chemical initiation of vinyl ester immediately before deposition was used to suppress collapse and enable large-scale thermoset printing. Structural stability was assessed by printing thin walls at various layer times and monitoring thermal gradients with an infrared camera. Stable printing was observed at a layer time of 4.50 min, approximately half the gel time of the material (8 min). Self-weight collapse occurred at short layer time (0.68 min), whereas warpage occurred at long layer time (6.50 min). A new behavior was discovered at intermediate layer time (2.25 min) where the heat generated by the reaction causes new, un-gelled layers to flow. Forced convection eliminates this behavior, stabilizing the 2.25-min layer time print. These findings motivated development of a less exothermic material system, which was used to print a large-scale mold and demonstrate the value of this understanding. By presenting these challenges of large-scale reactive thermoset AM for the first time, this work motivates focused studies of the complex interplay between rheological, thermal, and chemical behaviors to improve the feasibility of large-scale thermoset AM. Tensile properties of the printed material were also measured. Longitudinal and transverse elastic moduli are 3.79 and 2.95 GPa, respectively, and corresponding tensile strengths are 36.11 and 18.83 MPa. The glass transition temperature is 93.13 °C. [ABSTRACT FROM AUTHOR]