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Concrete is a very important material in the construction industry to develop the modern world. Many researchers are focused on this field to find some alternative materials for the ingredients needed to make the concrete mix. From the alternative material, it helps to save the natural resource available on earth and to make concrete eco-friendly. In the medical field, Butyl rubber waste is generated in huge quantity every day and dumped on the soil. Butyl rubber as a waste material is utilized as a partial replacement for stone aggregate in the production of lightweight concrete. In this research work were investigate about the thermal effects of butyl rubber waste used in the production of lightweight concrete. The butyl rubber as a coarse aggregate in the concrete mixes was partially replaced in 5%, 10%, 15%, and 20% respectively. The most effective substitute of butyl rubber waste in light weight concrete were used to be 10%. The thermal properties are examined Specific heat, Thermal diffusivity, Thermal conductivity, Specific heat capacity, analysis shows the 10% replaced butyl rubber concrete is less thermal conductivity compared to with all other mixes. Microstructural analysis like Scanned electron microscopic image (SEM), X-ray diffraction image (XRD), and FTIR is examined to study the surface structure of the butyl rubber replaced lightweight concrete. The use of butyl rubber in concrete helps to reduce the environmental problem. [ABSTRACT FROM AUTHOR]

It goes without saying that modern manufacturing processes priorities reducing machining costs by effectively optimizing a variety of machining process parameters like depth of cut, feed, and speed. Due to their high specific strength, titanium alloys (Ti-6Al-4V) are frequently utilized in the automotive, aerospace, bioindustry, nuclear power industrial, and medical applications. In this study, we addressed several machinability concerns of titanium alloys utilizing Physical Vapor Deposition (PVD) and Chemical Vapor Deposition (CVD) coated inserts. High hardness, corrosion resistance, specific strength, and biocompatibility are just a few of the excellent mechanical characteristics that are widely used in industries like the automotive, aerospace, and biotech. Titanium alloys have a limited thermal conductivity and a high specific heat, which makes it challenging to remove heat from the workpiece and chips during milling. This paper presents a literature review of the optimization of process parameters, highlighting the use of various techniques. [ABSTRACT FROM AUTHOR]

This study is about the comparison between the effect of mixing of surfactant sodium dodecyl sulfate (SDS) and without surfactant on the oxide, which consists of Al2O3, TiO2, and CuO. Obtained by synthesis using a mass fraction of 0.1% SDS and 1 gram of Al2O3/TiO2/CuO dissolved in 1000 ml of distilled water and then stirred using a magnetic stirrer for 1 hour at a speed of 650 rpm. Furthermore, without surfactant, using 1 gram of Al2O3/TiO2/CuO was dissolved in 1000 ml of distilled water and then stirred using a magnetic stirrer. Then the ultrasonic process was for 1 hour to get more homogeneous nanoparticles. The addition of surfactants to nanofluids can increase the stability and viscosity of the nanofluids. Obtained from the results of the Viscometer test with temperature variations from 20 °C-60 °C, the values of viscosity, shear rate, and shear stress. Then tested on Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR), and the results of the analysis of Conductivity Thermal and Specific Heat tests. This study aims to determine whether the addition of surfactant to oxide affects the value of viscosity, shear rate, shear stress, and thermal conductivity. [ABSTRACT FROM AUTHOR]

The paper presents solutions for selecting controllers for boiler houses and heating networks. It is shown that controllers are highly specialized in performing functions specific to the requirements for heating networks. Specialization can be seen at all levels - from input-output characteristics, microprocessor characteristics and data visualization and alarm signals on the computer panel. Among the selected functions, the functions of ensuring the operation of controllers according to the seasons "Winter - Summer", as well as the choice of modes in order to simplify control tasks, stand out. An important requirement for network controllers is low cost and the ability to operate the controller by a low-skilled user. Using the example of Vitotronic and Segnetics controllers, the implementation of the requirements for the selection of controllers for boiler houses and heating networks is demonstrated. [ABSTRACT FROM AUTHOR]

The thermophysical characteristics of the ZrO2 nanofluids based on a mixture of 60% water and 40% propylene glycol were estimated at temperatures ranging from 20 °C to 60 °C and volume concentrations ranging from 0.2% to 1.0%. The optimal conditions, coefficient of correlation R2, and root-mean-square error was all estimated using the adaptive-network-based fuzzy interface system (ANFIS) method. For all of the obtained thermophysical parameters, new equations were created based on the multi-linear regression analysis. Results indicated that, the thermal conductivity is enhanced by 16.41 and 24.39% at 1.0% vol. of nanofluid and at 20oC and 60oC over the base fluid. In the same manner, the viscosity is enhanced by 44.01% and 27.48% at 1.0% vol. of nanofluid and at 20oC and 60oC against the base fluid. The ANN approach revealing that, the R2 values for thermal conductivity is 0.996, viscosity is 0.9967, density is 0.99336, and specific heat is 0.999, respectively. [ABSTRACT FROM AUTHOR]

The article deals with the issue of using hydrogen fuel for an internal combustion engine. Interest in this alternative fuel is due not only to environmental friendliness, availability and renewability of the resource, but also to the specific heat of combustion of hydrogen. A list of the main optimization problems solved in the process of research based on the methods of statistical processing of the results of the experiment and modeling of the workflow is formulated. The results of computational studies are presented, based on the main design parameters of the engine (cycle, type, working volume, number of cylinders), as well as on regime parameters (power, speed). To ensure the required characteristics of the hydrogen-air mixture based on a commercially available carburetor, a developed engine power system is presented, which provides the ability to operate the engine on hydrogen. The results of comparative tests of the VAZ-2101 engine when running on hydrogen are also presented. In conclusion the main conclusions of the study are given as well as prospects for further research. [ABSTRACT FROM AUTHOR]

A cementitious composite carefully designed and mixed using aggregates, cement and waste materials forms a green concrete, providing potential for saving the environment, especially by reducing the carbon consumption in the construction industry. The reliable design of green cementitious composites' thermal conductivity leads to significant energy savings in residential buildings, especially when used as exterior or interior walls. This preliminary study briefly describes a concept of mathematical modeling of green concrete heat transfer since an effective solution to the problem will not only improve the energy saving inside the residential but also increase the efficiency in heat-protection of the structures. The study aims to generate a mathematical model to simulate the thermal properties into a computational model to understand the model behaviour under constant and elevated temperature considering steady-state and transient-state solutions. A two-dimensional thermal model is created first then the thermal properties such as thermal conductivity, mass density, and specific heats are assigned into the model. Seven variables to express the thermal conductivity of concrete are adopted in this study based on previous research. The analysis is then continued by specifying a heat source within two model geometries, i.e. a solid model and a model with cavity. The heat flux is also assigned to estimate the heat exchange between the boundaries. The model is then analyzed, the mathematical model is solved to generate the results of temperature, gradient, and heat rates as well as heat fluxes. This study enables the characterization of thermal transfer and distribution on a green concrete model to be used as approximations in predicting the trends related to thermal properties of a green cementitious composite. [ABSTRACT FROM AUTHOR]

The need for improved energy storage systems and electricity-saving devices is growing as a result of the current energy environment. High-temperature media, which are frequently doped with nanoparticles to create nanofluids, are being used as a promising option for energy storage. The specific heat capacity of these systems is their most important characteristic, and it is frequently enhanced by the addition of nanoparticles. This article introduces a straightforward method of comparison appropriate for larger sample volumes, particularly for the relative comparison of the amount of thermal energy stored. The merits and weaknesses of the procedure are outlined and examined, as well as the evolution of the experimental setup. [ABSTRACT FROM AUTHOR]

Incorporating graphene derivatives into advanced construction nanomaterials was attributed to their outstanding physical characteristics including thermal properties. In this paper, the heat storage and thermal stability of graphene oxide (GO)-reinforced cement mixture nanocomposites were investigated to study the influence of GO at low contents. Subsequently, the composites were characterized by Fourier transmission infrared, thermo-gravimetric analysis, and field emission scanning electron microscopy. The results showed that GO reduced thermal decomposition to 3% at 1.2 wt%, improved specific heat to 30%, and reduced thermal conductivity to15%. The cement mixture can stand high temperatures for specific applications depending on thermal stability and insulation property. [ABSTRACT FROM AUTHOR]

The use of nanoparticles has been seen in many different fields for the advancement of technology. Researchers has also found that the use of nanoparticles for enhancement of the properties of refrigerants. In this work, two refrigerants namely R134a and R600a have been analysed for their thermo-physical properties when mixed with various nanoparticles keeping the particle volume fraction as 5%. The nanoparticles which have been considered for the literature are TiO2, ZnO, CuO, and Al2O3. Various thermophysical properties are taken from literature and concurrency of results in case of temperature and pressure drop has been established. The analysis for the nanofluid has been done using ANSYS fluent software and the combined properties of nanofluids has been obtained using different mathematical correlations namely Pak and Cho model and Maxwell equation. The different thermo-physical properties that we obtained are thermal conductivity, viscosity, density, specific heat, and heat transfer rate. The results of the calculations and their respective temperature change and pressure drop are provided to explore the coefficient of efficiency for the nanofluid and to analysis the pumping power of the system. [ABSTRACT FROM AUTHOR]

A-site order and disorder NdBaMn2O6 (NBMO) manganites have been prepared to reveal the crucial role of A-site cationic ordering on the thermal response of these systems. The samples were characterized and studied using XRD, temperature (T) dependent specific heat (Cp), and magnetic field (H) dependent magnetization (M) measurements. M vs.H plots confirms the presence of antiferromagnetic (AFM) interaction in the ordered compound, which is suppressed by the A-site disorder and sets a ferromagnetic (FM) correlation at a low-temperature range. T variation of Cp data of A-site ordered NBMO shows an anomaly with thermal hysteresis around 265 K, which is correlated with the AFM transition in the system. However, such anomaly in Cp vs T data is suppressed in A-site disorder NBMO due to the absence of AFM transition. These results imply that the thermal response of these compounds explicitly depends on the degree of ordering of the A-site cations, Nd3+ and Ba2+. [ABSTRACT FROM AUTHOR]

The aim of Physics Practicum in the Basic Physics Laboratory is to prove experimentally the theories or laws underlying various physical phenomena. this aim is not achieved satisfactorily caused by the presence of various factors that result in the deviation of the experimental results compared to what should be according to the theory. In the calorimetry experiments case, the difference of resulted value to the expected value is caused by the neglect of the influence of ambient or environment temperature which is higher or lower than the temperature of the calorimeter. Calorimeter has a thermal behavior called water equivalence or heat capacity. Unlike the heat absorbed, which is easily calculated by the multiplication of mass and specific heat, the heat absorbed by the calorimeter and its supporting devices cannot only be calculated from the multiplication of mass and specific heat of the calorimeter material. The objective of this research is to explain a relationship between the water equivalence of the calorimeter and the amounts of media inside the calorimeter experimentally, using an experiment of heat fusion heat. The water equivalence of the calorimeter was calculated using experimental data of ice fusion heat with various variations in the mass of water inside. To have a better and more accurate result, the calculation is completed by Newton's correction of the measured temperature due to the influence of ambient temperature. From the results of the research used at the Physics Laboratory of the Bandung State Polytechnic, it can be shown that the value of the water equivalence of the calorimeter is not constant but depends on the mass of water inside the calorimeter. To the extent of a certain mass of water, the greater the mass of water, the greater the heat capacity of the calorimeter. [ABSTRACT FROM AUTHOR]

In this paper performance investigation of shell and helical tube (volute pipe) type heat exchanger (interchanger) is presented. In this analysis different parameters affecting performance of heat interchanger such as fluid temperatures, overall heat flow coefficient, flow rate of fluid, heat flow rate, thermal conductivity, thermal efficiency, tube diameter, tube length, thickness of tube, effectiveness etc. are taken into considerations. The effect of change in flow rate on other performance parameters is studied for same geometrical configuration. The rate of mass flow of warm and cold fluid is varied between 1 LPM and 2 LPM and results are presented. As the mass moving rate of both fluid escalate the overall heat flow coefficient and actual heat flow coefficient value also rises. The Heat interchanger effectiveness is adversely altered by mass flow rate of both warm and cold fluid. The escalation in rate of mass flow lowers down the effectiveness approximately up to 16%. The experimental value of effectiveness of heat interchanger is less than one. All the experimental results have been validated based on value of heat interchanger effectiveness. The NTU value is also affected by rate of mass flow of warm and cold fluid. As rate of mass flow increases, the corresponding value of NTU deteriorates. The specific heat of warm fluid is greater than cold fluid. [ABSTRACT FROM AUTHOR]

Basically, two categories of supersonic nozzles exist: conical contour nozzle (CCN) and thrust-optimized contour nozzle (TOCN). Conical nozzles are easier to design/manufacture, with little complexity whereas TOCN (bell-shaped nozzles) require more attention. However, the TOCN design allows for better expansion of exhaust gases even over shorter lengths. The present work explains method for designing the contour of a supersonic thrust-optimized nozzle using the method of characteristics (MOC). The design is based on the exit Mach number and specific heat ratio. Furthermore, this study deals specifically with the divergent section of the nozzle by implementing assumptions and/or calculations to the throat. The exit Mach numbers of 2.0, 2.5, 3.0, 3.5, and 4.0 with 100 characteristic lines are computed using method of characteristics and MATLAB. The expansion area ratio is compared with the ideal value and the respective error percentage is calculated for the given exit Mach numbers. [ABSTRACT FROM AUTHOR]

Cement composites exposed to high temperatures change their microstructure, composition and properties. In different temperature ranges, various physical and chemical processes take place in both their matrix and aggregates, which significantly affect the heat and mass transfer parameters, as well as the strength characteristics. In this paper, the effect of plasticizers on thermal properties of heat resistant composites based on calcium aluminate cement is studied. Thermal conductivity, specific heat capacity, and thermal strain are determined as a function of thermal load and compared with a reference material. The experimental results show that for the analyzed composites modified carboxylate is the most convenient choice while melamine-formaldehyde resin is found unsuitable. [ABSTRACT FROM AUTHOR]

The main objective of the research work is to find a satisfactory material for a disc brake which usually dissipates the heat to the environment easily. They often cause wear and tear which affects the performance of the disc brake. In this research work, 3 different materials for disc brake like Al 6601, SS416, tungsten carbide are selected to analyze the amount of temperature, pressure and heat generated of the disc brake for Steady State thermal analysis using Ansys 2021 and also compared the results among the 3 materials to withstand without fail. Alongside to reduce the maximum defects like thermal cracking are also studied which all makes the disc to fail when the dissipation of heat is in a proper manner. So in order to reduce these flaws the manufacturer need to develop a disc material which can endure a specific amount of heat, friction and maintain a good efficiency. From this research paper, the material Al 6061 showed higher heat flux compared to other 2 materials SS 410 and tungsten carbide i.e. the heat dissipation rate is more than SS 410 and tungsten carbide. [ABSTRACT FROM AUTHOR]

Direct particulate heating receivers (DPHR) are the most important part of the particle-based concentering solar power (PBCSP) systems in which the particles are exposed to direct high-concentrated sunlight. One variation of DPHRs is the obstructed flow receiver, which King Saud University (KSU) and the Georgia Institute of Technology have been developing for years. In this type of PHR, the particles fall freely in the form of a curtain through some obstruction to decelerate flow and allow the falling particles to absorb a considerable amount of thermal energy. The discrete structure presented in this design uses chevron-shaped mesh made of metallic alloy (Inconel 601) that was fixed on a Duraboard HD (an alumina-silica ceramic fiberboard). The design has been successfully tested using red sand and CARBOBEAD as heat transfer media. However, the interaction between the particulate and chevron mesh screen needs to be considered carefully at high operating temperatures. Careful consideration is the softening of the tip of the metallic chevron facing the sun. The tip of the mesh becomes soft at high temperatures and deforms which causes the particles to agglomerate on the chevrons, clog the chevron opening, and prevent particles from moving down to the end. Also, the particles get exposed to high flux for a long time which leads to particle fusing. Finally, a high degradation in the thermal efficiency of the system occurs as a result of this agglomeration and stops the whole operation of the plant. So, it is very important to study the interaction between the particulates and obstacles at high temperatures before installing it in the PHR cavity. This paper addresses these issues by presenting a study of the interaction between several chevron candidate materials and high-temperature candidate particles. The test was conducted in two stages: On-sun test and the lab test. Lab test is done by immersing the mesh screens with particulate materials and then heating at a specific temperature for several hours. For the chevron material, three candidates were considered: (a) stainless steel 316, (b) Inconel 601, and (c) ceramic mesh (WHIPOX). Three candidate particulate materials were considered: (a) Riyadh red sand, (b) Riyadh white sand, and (c) CARBOBEAD CP. Three temperature levels were considered in the lab test: (a) 800℃, (b) 1000℃, and (c) 1200℃. [ABSTRACT FROM AUTHOR]

The subject of the analysis are methods of determining the thermal conductivity of building materials with high and medium thermal resistance. The thermal conductivity of building materials is determined by the thermal conductivity coefficient λ [W/mK]. There are a number of ways to determine the thermal conductivity λ. The coefficient λ may be determined under the steady state conditions or by the non-stationary (dynamic) method. The test conditions in the steady state conditions are defined by the standards ISO 8301, ISO 8302 and EN ISO 8497. Measurement of the coefficient λ [W/mK] in accordance with the PN-ISO 8301 standard is performed in a plate apparatus with heat flux sensors, while the measurement in accordance with PN-ISO 8302 is carried out with a plate apparatus with a guarded hot plate. The PN-EN ISO 8497 standard defines the test conditions with an apparatus with a guarded and calibrated hot pipe. Under steady-state conditions, the measurement of the coefficient λ is based on the one-dimensional Fourier's law applied to the one-dimensional temperature field. An alternative measurement technique is the non-stationary method, based on the measurement of thermal diffusivity. Thermal diffusivity is a specific material property that characterizes heat conduction in transient conditions. The phenomenon is used that in a certain time range the temperature change is a function of the natural logarithm of time. This value allows you to determine how quickly the material reacts to temperature changes. Thermal diffusivity is defined as the quotient of thermal conductivity and the product of specific heat and density. Alternative methods of determining the thermal conductivity coefficient λ have been developed in various research centers. This applies in particular to the measurement of the thermal conductivity of ultra-thin microsphere thermal insulation coatings. The value of the thermal conductivity coefficient λ obtained with this method for the microsphere thermal insulation coating was 0.001 [W/mK]. At the Małopolska Laboratorium Budownictwa Energoszczędnego (MLBE), the thermal conductivity coefficient λ [W/mK] is determined both under steady state conditions with a plate apparatus and the non-stationary method. [ABSTRACT FROM AUTHOR]

This study details the use of materials for roof construction systems as a passive bioclimatic strategy, in the search for improving the comfort conditions of buildings located in a mid-latitude, humid and temperate climate, where the average annual temperatures fluctuate between 15 °C and 18 °C and comfort in a sedentary state range between 22 °C and 25 °C. Radiation, with a value of 4,116 w/m2, is above the comfortable limits, the optimum radiation being 430 w/m2. Having the environmental conditions indicated, the bioclimatic strategy referred to above was chosen, since, under this scenario, it is required to maintain an optimal comfort condition. Soil, gravel and grass, in addition to being materials with a high bioclimatic potential, have an ideal thermal conductivity. The proposed systems satisfy comfort, maintain an adequate internal temperature, are natural and environmentally sustainable systems. The use of physical scale models, as illustration models, allowed to clearly observe the behavior of each scenario, taking into consideration all climatic variables. [ABSTRACT FROM AUTHOR]

The current situation in the energy sector is reflecting the demand for electricity saving and advanced energy storage systems. As a promising option for energy storage, high-temperature media, often doped with nanoparticles, leading to the formation of nanofluids, are finding usage. The key property of these systems is the specific heat capacity, which is commonly being improved by the addition of nanoparticles. A simple specific heat capacity comparative method suitable for larger sample volumes is hereby introduced, applicable especially for the relative comparison of heat capacities. The development of the experimental setup, as well as the advantages and disadvantages of the method, are described and discussed. [ABSTRACT FROM AUTHOR]

We have investigated the various lattice distortions and their effect on thermal properties of Pr1-xBaxCoO3 cobaltates. The formulation to calculate the temperature-dependent (1K1-xBaxCoO3 (0.1≤x≤0.5) using modified Rigid Ion Model (RIM) are also presented. In addition, the results on the cohesive energy (ϕ) in orthorhombic perovskite phase, bulk modulus (B) and Debye temperature (θD) are calculated using RIM and Atoms in Molecules (AIM) theory. [ABSTRACT FROM AUTHOR]

Intermetallic compounds are known for their diverse behavior showing electronic, ferromagnetic, paramagnetic, and optical properties that correspond to vivid applications in the industrial and technological field. The main purpose of this paper is to calculate specific heat at constant volume and specific heat at constant pressure for CuZn using density functional theory (DFT) and the full potential linearized augmented (FP-LAPW) method as incorporated in the WIEN2K code. Thermodynamic quantities such as specific heat at constant volume CV, and at constant pressure CP are evaluated using the Quasi-harmonic Debye model. Further, variation of CV and Cp are plotted within the definite pressure and the temperature ranges vary from 0 GPa to 50 GPa and 0 K to 1000 K, respectively. The calculations of CV and Cp give valuable data for experimental studies. [ABSTRACT FROM AUTHOR]

This study tried to test the construction of a parabolic solar power generator by using of concentrating mirror collector with a line focus collection. Heat from the sun is concentrated on the absorber pipe that resides at the focus line of the mirror reflector in which the water absorbed heat. The amount of heat adsorbed depends upon the length of pipe used which located in the focus of the reflector as well as the reflection surface type and the ambient conditions. This parabolic solar energy generator is very useful because it is environmentally safe, not expansive even if it is compared with point focus, technically less difficult, and no fuel required. This work described as well the unit of the sun tracking system through the manual lever tilting at the parabolic dish for the capturing of the sun energy. The entire arrangement has been fixed on a hinged frame that is supported by a slotted lever to tilt the parabolic dish reflector to a variety of angles so that the sun stays always directed to a collector at various day periods. This research tried to construct a heat generator with a specific required output water temperature by adjusting the working fluid flow rates. The efficiency of parabolic heat generation with pipe for heat transfer at different water flow rates was calculated. [ABSTRACT FROM AUTHOR]

A structural and optical property of 2-Amino-5-Bromo benzaldehyde (2A5BB) is obtained by Density Functional calculations. It is known that the bond lengths and bond angles shall be predicted very well and the calculated C‒C‒C bond angle values of the benzene rings are in the range of 120 degree. The correlation coefficient (R2) values between the experimental and calculated bond distances were found to be 0.995. It is found that the large hyperpolarizability value of the title molecule indicates that it has considerable NLO properties. Adapting B3LYB/6-311+++G (d, p) base Set, HOMO energy (EHOMO), LUMO energy (ELUMO), energy gap (ΔE), Electro Negativity (χ), Chemical Potential (μ), Global Hardness (η) and Softness (S) are determined for the title entities. The behaviors of 2A5BB under different thermodynamic constraints are explained in terms of the specific heat of a solid. [ABSTRACT FROM AUTHOR]

Information on the application of thermodynamic parameters to assessing the aging of coatings is presented. It is proposed to divide the aging process into a number of quasi-stationary processes, for which the equations of reversible thermodynamics can be applied. It was found that with aging of the coatings, an increase in the specific heat of wetting and a change in entropy are observed. Revealed different rates of change in the free energy of the coatings in the process of moistening. The maximum decrease in free energy, which characterizes the course of structure-forming processes, occurs at the early stage of moistening. Further moistening leads to the predominance of destructive processes characterized by a decrease in the value of changes in free energy. With UV irradiation at the first stage of aging, the change in the specific free energy is caused by structure formation with an increase in volume. Subsequently, a decrease in the rate of change of free energy indicates a slowdown in the process of structure formation and competition between the process of structure formation and destruction with a decrease in the volume and weight of the coating. With further UV irradiation, the change in free energy increases, but this time due to the destruction occurring in the system. [ABSTRACT FROM AUTHOR]

Nanofluid is of great attention because of the physical properties and the effective thermal conductivity. Many applications of nanofluids are in improving the performance of heat exchangers. This study aims to measure and analyze the thermophysical properties of SWCNTs. Concentrations used in nanofluids are 0.1%, 0.3%, and 0.5% with distilled water as the base fluid. The process of nanoparticle characterization SWCNTs is done by testing the thermal conductivity and specific heat using C-Them TCI (thermal conductivity analyzer), viscosity test using a viscometer NDJ-8S, density test using a density meter, METTLER toledo, test FTIR (Fourier Transform Infra Red), XRD (X-Ray Diffraction) test, and SEM (Scanning Electron Microscope) test. SWCNTs have high mechanical strength, thermal conductivity and good electrical conductors, structure and strength of high appeal. SWCNTs nanofluids showed an increase compared to distilled water in various variations. [ABSTRACT FROM AUTHOR]

This experimental study aims to determine the characteristics of the physicochemical properties of DWCNTs material which aims to improve heat transfer performance by utilizing nanoparticle based DWCNTs that can be used as fluids in heat exchangers. The material used in this research is DWCNTs powder mixed with water with a concentration of 0.1%, 0.3%, and 0.5%. The process of characterization of DWCNTs nanoparticles was carried out using density test, viscosity test, thermal conductivity test, and specific heat test to determine their physicochemical properties. The SEM-EDX (Scanning Electron Microscope – Energy Dispersive X-Ray) test, XRD (X-Ray Diffraction) test, and FTIR (Fourier Transform Infra-Red) test were also carried out to determine the characteristics of the material. The research found that the highest density and viscosity were found in 0.5% DWCNTs, the highest thermal conductivity was found in 0.5% and the specific heat was found in 0.1% DWCNTs. From the SEM-EDX test, it was found that DWCNTs have a nanofiber structure bonded to each other and form clumps, the XRD pattern of DWCNTs is known to be similar to the XRD of MWCNTs which is made of carbon material, and from the FTIR test, it is known that the highest peak is the C – H (alkane) group. As a result, DWCNTs has the potential as a nanofluid which can later increase the convection heat transfer coefficient in the heat exchanger because it has good conductivity and specific heat. [ABSTRACT FROM AUTHOR]

The molten jet's behavior on a tilted plate is one of the important behavior that have to be considered when the jet continuously impinges at a specific time. It can simulate the heat transfer and solid-liquid interface reaction, including the molten fuel impingement to sacrificial plates. Series of experimental simulations have been conducted for analyzing low-density plate erosion behavior. This study focused on the erosion rate and molten pool effect, which occurred on the tilted plate. Paraffin was utilized as plate material with 150 mm and 8 mm of diameter and thickness of the plate. The plate was tilted at 15° from the x-axis. The molten materials were varied, such as water, oil, paraffin, candle, and lubricant oil, and set at 90 °C of initial flow temperature. The molten jet was preheated on a stainless steel chamber and gravitationally accelerated through a 5 mm diameter of the nozzle tip. The experiments were captured by some cameras and a thermal camera to analyze the temperature distribution during the impingement process. The results showed some different erosion rates, spread patterns, and the leading edge of each kind of molten material. It was depended on some physical properties such as density, thermal conductivity, and specific heat. The density and thermal conductivity will affect the pool extinguish on the plate surface. The experimental result could predict the tilted plate's erosion during the impingement of molten fuels to the sacrificial plates. [ABSTRACT FROM AUTHOR]

The article shows the possibility of using the technology of recycling of secondary energy resources (SER) of the organic Rankine cycle (ORC). The perspective developments in the field of waste heat development due to the introduction of the ORC at the boiler houses of the transport infrastructure, ship installations are analyzed. The aspects that complicate the widespread introduction of a specific technology into the heat economy of stationary and mobile power facilities are identified: high weight and size characteristics of heat exchange equipment. It is shown that the solution to this problem lies in the construction of detailed methods of mathematical modeling. An increase in the detail of the mathematical model is possible mainly due to the use of specialized software systems in the calculations. In addition, refinement of existing analytical methods is equally capable of adjusting model building. The paper compiled a methodology for preliminary mathematical modeling of condensing equipment using the engineering complex NIST REFPROP DATABASE Version 8.0. The specified program has a wide range of tools for the thermophysical properties of working bodies and with its help; it is possible to supplement the above technique. Based on the above factors, it can be concluded that with a more detailed analysis of the problems of integration of ORC converters, they can become a very promising technology for heat recovery. [ABSTRACT FROM AUTHOR]

Solar photovoltaic/thermal technology has been widely used in private and commercial buildings because it produces heat and electricity simultaneously. To improve the performance of PV/T systems, nanofluids are used as potential heat transfer because of their high thermal conductivity. This paper summarizes the thermophysical properties of nanofluids (thermal conductivity, thermal diffusivity, viscosity, density and specific heat), the effect of fluid flow configuration (spiral, straight, mesh), cross-sectional shape (rectangle and circle) on PV/T performance, to the application of nanofluids as PV/T coolants. The heat transfer from the back of the PV module was shown to increase with the increasing concentration of nanoparticles in the base fluid. The performance of nanofluids is also at ambient temperature because it affects the viscosity. The PV/T power generated by the addition of nanofluid cooling increased by 6%. In addition, differences in fluid flow configuration, type of nanoparticles, size of nanoparticles and ambient conditions affect the performance of PV/T. The rectangular shape is able to increase the electrical efficiency by 11.4%, while the circular cross-section is 6%. These are some of the key parameters for using nanofluids as coolants to improve the performance of PV/T systems. [ABSTRACT FROM AUTHOR]

Zeolitic imidazolate frameworks represent new materials falling into the large group of metal–organic frameworks with wide application potential. The present work is focused on the study of fundamental properties of imidazolate compound [{Zn(mIm)2·2H2O}∞],which is referred in literature as ZIF–8. Measurements of infrared spectra in the mid-infrared and far-infrared regions at room temperature as well as heat capacity in the range from 2 to 300 K were performed. The character of the infrared spectra suggests why the specific heat data values are so small, and even at 300 K the values are much lower than the classical value of 3sR resulting from the equipartition principle. Analysis of the specific heat of the ZIF–8 powder sample within the Debye model including only the contribution of three acoustic phonon branches revealed deviations of the model from experimental data already above 20 K. Low–frequency optical modes as indicated by infrared spectra are responsible for the observed deviations. [ABSTRACT FROM AUTHOR]

Heat sink is an efficient mechanical procedure in which embodied heat is channeled out from a hot substance to a fluid medium. Till now, this application is mostly used in electrical and mechanical devices ranging from microprocessors to automobiles. Concrete, being an inert building material, can inherently store substantial heat energy because of its low thermal conductivity and high specific heat, which is why concrete shows quite good performance in thermal insulation and is reasonably high in fire resistance. During a fire incident, ambient temperature goes up and as a consequence, concrete keeps heated up inside its body and dissipate accumulated heat very slowly into the surroundings. A good number of experimental studies have previously been done on improvise fire resistance and enhancing the insulation property when exposed to fire by using high-strength concrete. In this experimental study, heat sink procedure is implemented in concrete to improve the heat transfer behavior of concrete when exposed to fire. Only plain concrete specimens are analyzed at an elevated temperature. The temperature of concrete specimens is recorded by a data logger. Temperature differences and heat transfer rate of normal concrete specimen and concrete specimen with embedded heat sink are then compared. It is observed that heat sink can dissipate embodied heat in concrete with substantial efficiency. The rate of heat transfer increases with the increase of flow of water within the heat sink. [ABSTRACT FROM AUTHOR]

This article discusses the problems of calculating heat losses through various corners of the outer walls of buildings with effective thermal insulation. An overview of three methods for calculating heat losses for these enclosing structures is made. The calculation of heat losses of three corner rooms of fundamentally different sizes was carried out according to the methods considered. The limits of using the calculation for specific heat loss are considered. The results of numerical modeling of heat losses through the corner enclosing structures are shown. The dependence of specific heat losses through the corners of the premises of the considered enclosing structures on the angle was revealed. [ABSTRACT FROM AUTHOR]

When measuring the temperature of a stream of compressible fluid using a temperature sensor, experimenters must address the problem of the effect of the compressibility of the locally decelerated fluid in the near neighborhood of the sensor on the rendered temperature. Generally said, the temperature rendered by a temperature probe positioned within an airflow depends on the external flow velocity, the specific heat of the fluid, the thermodynamic temperature, and the recovery factor of the probe. A method of measuring the velocity of a flowing compressible fluid that takes advantage of these properties is called Recovery Temperature Anemometry (RTA). This, unfortunately, means there are two unknown properties in real-time measurements – the velocity and the thermodynamic temperature of the fluid. This article is focused on a possible solution to the mentioned problem and the development of appropriate probes. By using two probes with different recovery factors, the need for knowing the thermodynamic temperature is eliminated so that a combination of two temperature probes with different recovery factors can be used for the velocity measurement. As described in this paper, by using multiple temperature sensors with different recovery factors, the temperature of the flowing fluid can be eliminated, leaving only one unknown quantity in the entire problem, which is the velocity of the flowing fluid. The article describes the theoretical basis of the problem, the purpose of multi-element probe, the verification multi-element temperature probe behavior, the measurement technique, and the results. [ABSTRACT FROM AUTHOR]

In this investigation alcoholic liquid mixtures of isopropyl with benzene were used to evaluate the behavior of binary liquid mixtures under ultrasonic characterization at varying temperatures. The Pseudo counter part of Gruneisen parameter is defined for many liquids, Pseudo-Gruneisen parameter decreases with increase in temperature except for liquid water. For the liquid mixtures over the temperature range 303K, 308K, 313K, 318K & 323K ultrasonic velocity and other acoustical parameters have been calculated. From 303K to 323K, the thermodynamic interaction of liquid mixtures was studied experimentally by using the ultrasonic interferometer. Other parameters such as density and viscosity were measured at different temperature range. In addition to this internal pressure (πi), solubility parameter (δ), activation energy (G), Pseudo – Gruneisen parameter (Г), reduced volume (Ṽ) and specific heat capacity (C) were calculated. The results of isothermal compressibility (βT) and specific heat ratio (γ) increases as the mole fraction increases. The values observed and plotted by the graph shows the similar properties for volume expansivity, reduced volume and specific heat capacity. If temperature increases the internal structural properties of the system increases, while comparing with the room temperature. If the temperature increases the Pseudo – Gruneisen parameter decreases for binary liquid mixtures. [ABSTRACT FROM AUTHOR]

The ferromagnetic semiconductor Ga1-x MnxAs has been studied intensely over the last decades and has become a model system for diluted ferromagnetic semiconductors. It is now widely accepted that the ferromagnetism in Ga1-x MnxAs arises from hole-mediated exchange interaction between the local magnetic moments of the Mn, and the mean-field-like Zener model has been widely used to describe this system. [ABSTRACT FROM AUTHOR]

Heat exchangers plays significant role in engineering because they transfer heat between two different flow streams and temperatures. There are various designs of heat exchangers based on construction, size, direction of fluid flows. Amongst, industry has the most prevalent application for double pipe heat exchangers due to its simple and economical design. Proper analysis is required prior to selection of suitable application specific heat exchanger with good performance. In the present work, double pipe counter flow heat exchanger has been considered for the analysis. Simulation of heat exchanger has been done using MATLAB SIMULINK based on the NTU approach. Variation of heat transfer coefficients, heat transfer rate, effectiveness with mass flow rates have been discussed using the simulation results. The same design of the heat exchanger has been analysed with ANSYS CFD. Results obtained from both the models have been validated and the reasons for variations in result have been identified and discussed. Some of inferences obtained with CFD analysis has been discussed. [ABSTRACT FROM AUTHOR]

The problems of organizing heat supply to settlements in the central ecological zone of the Baikal natural territory are being discussed. The advantages of decentralized schemes when using electrical energy as the primary energy source for heat supply are carried out. A comparative analysis of the cost of heat energy for consumers with various options for technical solutions is carried out. Indicators of the specific cost of heat energy and the Levelized Cost of Energy are used as estimates of the economic efficiency of options. The results of the study showed that the most effective in terms of both considered economic indicators is the use of autonomous boiler houses in combination with air source heat pumps and solar heating systems. [ABSTRACT FROM AUTHOR]

It is very important to reduce the cost of modern industries and pollution which represents major damage to the environment. In these days, it is increasingly using waste materials in the promotion and formation of a new material, so this research used polyester with ash from sunflower husk for preparing particulate composites, then examining the possibility of reused the wasted material in reinforcing of composite materials and investigating the new composite properties according to unsaturated polyester. Sunflower husk ash added to unsaturated polyester material at different concentration (2.5, 5, 7.5 and 10) wt.% by hand lay-up method to prepare the specimens that are used in inspections, the inspections that are applied to these specimens include (tensile strength, modules of elasticity, impact strength, hardness, thermal conductivity, thermal diffusivity, specific heat, density and water absorption). The results showed that the tensile strength, elastic modulus and impact strength improved with the increase of the ash percent. The tensile strength is increased from (18 MPa) for unsaturated polyester, while get maximum value (31.7 MPa) for (5 %wt.) percent of ash. Also can noted that the hardness decreased with the increase of ash percent from (80 shore D) for unsaturated polyester, while get minimum value (66.7 shore D) for (10 %wt.) percent of ash. [ABSTRACT FROM AUTHOR]

This research studied some properties of particulate composite material prepared by adding ZrO2 ceramic particles having a particle size of (< 25 µm) to PMMA with a weight fraction of (0, 2, 4, and 6) %. Some mechanical and physical tests were conducted to evaluate the properties of the prepared composite material. The results manifested that the values of compression strength, bending modulus, thermal conductivity, thermal diffusivity, specific heat, hardness and water absorption increased with the filler percentage increase by increasing the weight fraction of reinforcement. On the other hand, the values of impact energy and fracture toughness decreased with the increase of reinforcement percentage. The best results were obtained at 6% weight fraction. [ABSTRACT FROM AUTHOR]

Superheated tubes in the boiler are subjected to extremely hot fluid to stream its flow. Any material which has specific heat resistance and good strength ability are highly required in this part. Alloy steel such as Cr-Mo becomes the most suitable material and commonly used in the superheated tubes. This research was conducted to analyze behavior of mechanical properties when alloy steel Cr-Mo was repaired during welding processes due to defect possibility appearing in the welding result. Alloy steel utilized in this research is SA 335 welded with E 8018 electrode of Shielded Metal Arc Welding (SMAW) machine. The two kinds of welding procedures were compared to one another, in which the first one was only subjected to normal welding procedure and the second one was subjected to repair welding procedure. The hardness results of material were declined in line with more heat input subjected to material, where normal welding procedure average hardness value is 210 HVN, while repair welding procedure average hardness value is 180 HVN. Another result was by examining the micro structure of both procedures and calculating the percentage of ferrite formations in both heat-affected zones, in which normal and repair welding procedure ferrite percentages are 45 % and 49 % respectively. [ABSTRACT FROM AUTHOR]

Molten salts are growing in popularity as heat transfer fluids in various energy-storage technologies. The most important quantity determining the properties of the molten salt is the specific heat capacity. In this contribution, various sample preparation techniques and configurations of the DSC measurement are discussed. The measurements were performed on a potassium and sodium nitrate mixture, which was studied using SEM, EDS and XRD. The most suitable experimental setup as well as the advantages and disadvantages of each of the measurement configurations were then defined. [ABSTRACT FROM AUTHOR]

The presented work aims to the describing of method for determination of the thermal properties of the glass fibers reinforced polyester composites. The thermal conductivity, specific heat capacity and thermal diffusivity of the estimated materials were observed. All the parameters were determined by the step wise transient method using a differential fractal heat transfer model. From the results were observed the dependence of the thermal parameters on the sample thickness. The thin samples are appropriate for the measurement of the thermal conductivity because homogeneous thermal field in the sample. For larger thicknesses, heat is spread over a smaller area. On the other hand, the thick samples are usable for measurement of the specific heat capacity. For smaller sample thicknesses (small volumes) there are greater heat losses to the surroundings. The correlation between thickness of the sample and its thermal properties were found. The real material thermal parameters were determined by data extrapolation or interpolation. The thermal conductivity of examination composites was estimated in range from (0.15 to 0.20) W/m/K and the specific heat capacity as (2000 – 3000) J/kg/K. [ABSTRACT FROM AUTHOR]

A gas-phase deposition is one of the types of additive technologies and is a process of applying a film or coating to the cooled surface, that is, a continuous layer of material that has, among other things, a nanocrystalline structure. Currently, the development of this and other additive technologies has made it possible to apply a variety of coatings with different properties. In most works devoted to the deposition numerical simulation, the features of gas heat exchange with the surface are not taken into account, while the temperature of the surface on which deposition occurs is one of the fundamental factors determining the film structure. In this paper, a numerical model of heat transfer during gas-phase deposition of a material on a cooled curved substrate is constructed, taking into account the specifics of heat exchange of the gas medium. A numerical analysis of the mathematical model is performed, and the influence of various heat transfer mechanisms on the temperature distribution in the substrate being built up is shown. [ABSTRACT FROM AUTHOR]

Based on the Rietveld method, the quantitative phase analysis was performed of AlMgB14-based materials obtained by self-propagating high-temperature synthesis (SHS) of Al12Mg17-B powder mixture using a chemical furnace based on titanium and silicon of various thicknesses (1, 2, and 3 cm). Al0.5Mg0.5B2, AlMgB14, MgAl2O4 phases were identified in the obtained materials: the total contribution to the integrated intensity was no less than 98%. Ab initio calculations of the lattice energy, thermodynamic characteristics, and elastic moduli of the main phases were performed both in the initial (reference) and after the refined state. The phase content in the obtained AlMgB14 materials depends on the chemical furnace thickness. In the materials obtained in the chemical furnace with a thickness of 2 and 3 cm, AlMgB14 phase is dominated, which is modified during the synthesis with an increase in the lattice stability. A sharp decrease in the elastic characteristics and specific heat of the dominant phases was found, which is expected to stimulate a change in the characteristics of the near-surface layers of the synthesized AlMgB14 materials. [ABSTRACT FROM AUTHOR]

Using solid particles as a heat transfer media (HTM) in concentrated solar power applications gained growing attention lately. Unlike molten salt, solid particles offer high operating temperatures (greater than 1000°C), no freezing issues, abundantly availabile, high thermal energy storage capacity, low-cost, non-corrosive, and applicability of direct irradiation. Comprehensive knowledge of thermophysical and optical properties of solid particles is essential to ensure an effective harnessing of solar energy. The most important considerations when selecting solid particles include (1) thermophysical and optical properties, (2) thermal resistance, (3) crack resistance (4) satisfactory health and safety risks (5) availablity, and low-cost. It is also imperative to consider optical and thermophysical characteristics that might change from what they were as received after cyclic heating for a long time. Therefore, the knowledge of the thermal performance of particulate materials becomes significant before using them as HTM. In this study, some particulate materials have been chosen to study their feasibility to be used as heat transfer and storage media for the particle-based central receiver tower system. These particulate materials include red sand, white sand, ilmenite and carbobead CP. The cyclic heating was performed on the particulate materials for 500 hours at 1200°C. Weighted solar absorbtance and specific heat have been measured for the candidate particulates as received and after cyclic heating (aging) for a specified duration of time. [ABSTRACT FROM AUTHOR]

The Titanium Grade 5 (Ti-6Al-4V), with density 4.43 g/cm3 at room temperature (RT), was used to test temperature characteristics of the thermal diffusivity and thermal expansion in the temperature range from RT up to 1100 ℃. Two kinds of the NETZSCH laser flash apparatus, i.e. the low temperature LFA 467 and the high temperature LFA 427 were used. As a reference material a sample made of stainless steel A310 provided by NETZSCH, with density 7.83 g/cm3 at RT, was utilized with temperature range from RT to 480 ℃. The reference material was used to determine the thermal conductivity and specific heat by comparative method. The results of the thermal diffusivity tests of the Titanium Grade 5 performed by means of the LFA 467 and the LFA 427 apparatus showed to be consistent to each other. Thermal expansion measurements of the Titanium Grade 5 were carried out applying the NETZSCH dilatometer DIL 402 C. To analyze temperature characteristics of the specific heat and thermal conductivity the thermal expansion of the tested material was taken into account. Test results of the thermal expansion showed that above 800 °C subsequent heating cycles differed from each other. The sample became very fragile after removal it from the device. The cracking effect of the sample may be due to the absorption of gases from the environment, despite the fact that the tests were carried out in an argon environment. [ABSTRACT FROM AUTHOR]

As one of the most common methods for natural ventilation of building, solar chimney has been studied widely in the literature. Various forms of solar chimney have been proposed for enhancing its performance for a specific application, i.e ventilation and/or heating. In this work, we examined performance of an L-shaped comprising horizontal and vertical air channels connected serially by a numerical model based on the Computational Fluid Dynamics (CFD) method. Two different total lengths and gaps of the chimney were tested. The considered parameters included the flow rate, temperature rise, and thermal efficiency. The results show that as the horizontal portion is longer than the vertical one, the flow rate decreases while the temperature rise increases. The variation of the thermal efficiency depends on the ratio between the gap and the total length of the air channel. The findings can help to select suitable configurations of an L-shaped for a specific cooling or heating application. [ABSTRACT FROM AUTHOR]

This study determined the thermophysical parameters of Ganoderma lucidum, such as volume density, specific heat capacity and latent heat of vaporization of the moisture in the material. The volume density was experimentally determined using the method of liquid displacement and Archimedes principle using Toluene solvent. The specific heat capacity was determined by the method of a mixture using a calorimeter. The experimental data were statistically analyzed to determine the volume density and the specific heat capacity of Ganoderma lucidum as the function of moisture content of Ganoderma lucidum. The increase of the moisture content of Ganoderma lucidum increased the volume density and the specific heat capacity of Ganoderma lucidum. The volume density increased from 607.7 to 824.8 kg/m3, and the specific heat capacity increased from 2087.3 to 3480.3 J/kg.°C as the moisture content of Ganoderma lucidum varied in a range of 0.18 and 2.33 (db). Besides, the study established the formula for calculating the latent heat of vaporization of the moisture in Ganoderma lucidum as the function of the drying air temperature and the equilibrium moisture content of the material. The latent heat of vaporization of the moisture in Ganoderma lucidum decreased when the drying air temperature and the equilibrium moisture content increased. [ABSTRACT FROM AUTHOR]