Determination Of Specific Heat Research Articles

Arduino-Based Data Acquisition Device Design for Specific Heat Determination of Hot Vegetable Oil

Vegetable oil is commonly used for cooking and frying at high temperatures. Information on the oil's specific heat in a process can help estimate the time and energy spent to reach a particular temperature. However, finding an accurate and affordable instrument for measuring specific heat at high temperatures was complex. This study aimed to design a prototype data acquisition device (DAQ) that can support the specific heat of high-temperature vegetable oil determination using the Joule experiment and Newton's correction. This study had two stages: prototype design/construction and prototype testing. The DAQ prototype consisted of a PZEM-003 power sensor, a PT100 temperature sensor, a relay, and an Arduino Mega 2560. The measurement results were displayed on an LCD and recorded in Microsoft data streamer. The prototype was tested by comparing the temperature, voltage, and current with commercial instruments resulting in accuracy and precision of 99.97% (99.95%), 99.97% (99.86%), and 99.99% (99.86 %), respectively. Performance tests showed that the specific heats of canola, corn, and sunflower oils at 100°C based on DAQ data analyzed separately were 2.119 J/kg.°C, 2.082 J/kg.°C, and 2.458 J/kg, respectively. The specific heat values were close to those in the reference, with an accuracy of 94.22%, 97.29%, and 99.80%, respectively. Keywords: ATmega2560, DAQ, Heat capacity, Hysteresis, Vegetable oil

Determination of Specific Heat in Experiments with Pulsed Electric Heating

Determination of Specific Heat in Experiments with Pulsed Electric Heating

Experimental Determination of Polycrystalline Salt Rock Thermal Conductivity, Diffusivity and Specific Heat From 20 to 240°C

Salt rock is recognized as one of the most suitable parent rocks for geological disposal of high level radioactive waste due to its low permeability, good ductility, good thermal conductivity and damage self-healing properties. The thermal conductivity of salt rock directly affects the temperature of disposal storage and surrounding rock, high temperature will lead to a series of problems such as nuclear waste storage tank rupture, mechanical and permeability reduction of surrounding rock. In this paper, the thermal conductivity, specific heat and thermal diffusion coefficient of NaCl single crystal made by crystallization method in the laboratory and polycrystalline salt rock from Khewra salt mine were measured in the range of 22–240°C by the transient plane source method. The results showed that the thermal conductivity and thermal diffusivity of salt rock decrease gradually with the increase of temperature, while the specific heat capacity increases with the increase of temperature. The thermal conductivity of salt rock is slightly lower than that of single-crystal NaCl. The reason for this phenomenon may be that there are a few pores in salt rock. Based on the experimental data, the models of thermal conductivity, thermal diffusivity and specific heat of salt rock with temperature were established. The results can provide a reference for the construction of underground salt rock high-level radioactive waste disposal repository. Based on the thermal conductivity model of polycrystalline salt rock established in this paper, the temperature field evolution during the operation of the underground salt rock high-level nuclear waste repository in 1,000 years was studied. It was found that the temperature of the glass solidified of high-level radioactive waste reached the highest (177.6°C) and then dropped rapidly. The decay heat radiation influence radius of the nuclear waste reaches its maximum in about 50 years of operation of the repository and then gradually decreases.

Influence of nanoparticle concentration on thermophysical properties and heat transfer performance of Al2O3 nanosuspension for refrigeration system

Different types of conventional heat transfer fluid have been synthesized according to different thermal application for energy conservation. The recent advancement in last two decades have been found by using nanofluid. The nanofluid are modified heat transfer fluid which uses the dispersed nanoparticles within the fluid to enhance the thermo physical properties. The experimentation in the paper shows the development of Al2O3 based nanofluid for the refrigeration application and the effect of nanoparticle concentration on different thermo physical properties of nanofluid. The base fluid in the experiment used are polyester oil (POE) and mineral oil (MO) which are commonly used as compressor lubrication oil in a refrigeration system. The synthesis of nanofluid was carried using two step method with different weight percentage concentration of 0.02%, 0.04%, 0.07% and 0.1%. The experiment followed for the determination of thermal conductivity, viscosity and specific heat. Use of Hamilton model for thermal conductivity and brinkman model for viscosity has utilized and compared against the experimental observation. The highest gain in the thermal conductivity by almost 57% noted in by using the 0.1 wt% of Al2O3 nanoparticles with mineral oil with slight increment in the viscosity. All the synthesized nanofluid were found to be stable as well as without agglomeration.

Determination of oxidation specific heat in mines

During the design, construction and operation of coal shafts, thermophysical calculations are necessary to determine the climatic parameters (temperature, relative humidity) of the ventilation cannon and to ensure their optimal values. The share of oxidative processes in the total heat balance is in the range of 25%. The heat emitted by local sources is about the same. And the remaining 50% of the ventilation flow is transmitted from the rock mass.

Journal of Physics: Conference Series High-pressure specific heat technique to uncover novel states of quantum matter

AC-specific heat measurements remain as the foremost thermodynamic experimental method to underpin phase transitions in tiny samples. However, its performance under combined extreme conditions of high-pressure, very low temperature and intense magnetic fields needs to be broadly extended for investigation of quantum phase transition in strongly correlated electron systems. In this communication, we discuss the determination of specific heat on the quantum paramagnetic—insulator SrCu2(BO3)2 by applying the AC-specific heat technique under extreme conditions. In order to apply this technique to insulating samples we sputtered a metallic thin film-heater and attached thermometer onto sample. Besides that, we performed full frequency scans with the aim to get quantitative specific heat data. Our results show that we can determine the sample heat capacity within 5% of accuracy respect to an adiabatic technique. This allows to uncover low energy scales that characterize the ground state of quantum spin entanglement in SrCu2(BO3)2.

Modeling of freezing processes of ice floes within the framework of the TPM

Sea ice is floating ice which is formed by the freezing of ocean water in the polar regions of the Earth, i.e., the Arctic and the Antarctic. Thus, a closed smooth ice surface can be formed consisting of these ice configurations. In recent years, the simulation of sea ice evolution, especially for the use in climate models, became more important, see, for instance, Danilov et al. (Geosci Model Dev 8:1747–1761, 2015) and the references therein. In the present paper, a coupled macroscopic model based on the Theory of Porous Media is introduced in view of the finite element simulation of the coalescence of ice floes due to freezing in calm sea and weather conditions. Attention is paid to the description of the temperature development, the determination of energy, enthalpy, specific heat and mass exchange between water and ice as well as volume deformations due to ice formation during freezing. The main idea is based on a theoretically motivated evolution equation for the phase transition of ice and water, which guarantees the thermodynamical consistency. Numerical examples show that the simplified model is indeed capable of simulating the temperature development and energetic effects during phase change.

Analysis on the determination of specific heat of air at constant pressure

Heat calculation is often encountered in industrial production and life. For example, the calculation of flue gas heat release or the heat absorption of working medium in thermal equipment in thermal power plant boiler is a common heat calculation. This paper mainly introduces the experimental principle and method of specific heat of gas, and measures the average specific heat of air at constant pressure. Through this experiment, we can be familiar with the basic measurement methods of temperature, pressure, heat and flow in the experiment. In this paper, we compare the experimental data with the actual data, and analyze the cause of the error.

Specific forward/reverse latent heat and martensite fraction measurement during superelastic deformation of nanostructured NiTi wires

This study analyses the thermomechanical tensile behaviour of a cold drawn Ti-50.9at.%Ni wire submitted to heat treatment at 598 K for 30 min, which is below the recrystallization temperature (623 K). Such low temperature heat treatment induces a superelastic loop without a stress “plateau”. However, the absence or weakness of peaks on its differential scanning calorimetry prevents the determination of specific latent heat. This is a common effect of nanostructured materials such as superelastic wires. A method using strain and temperature field measurements was developed and used to determine thermal power and thermal energy during superelastic tensile tests through a heat balance. From these results and using a thermodynamic approach, forward and reverse specific latent heat and the martensite fraction are estimated as a function of strain and stress.

Synthesis and characterization of ditetradecyl succinate and dioctadecyl succinate as novel phase change materials for thermal energy storage

This paper deals with the synthesis, characterization, thermal properties and thermal reliability of 1-tetradecanol and 1-octadecanol-succinic acid esters as a novel solid–liquid phase change materials (PCM) for thermal energy storage (TES). Ditetradecyl succinate (DTS) and dioctadecyl succinate (DOS) were synthesized by using succinic acid and excessive amount of fatty alcohol under vacuum and without catalyst. The esterification reaction yield was found above 95%. High purity ester compounds were characterized structurally by 1H nuclear magnetic resonance (1HNMR) and fourier transform infrared (FT-IR) spectroscopy techniques as thermophysical properties were investigated using a differential scanning calorimeter (DSC) and a thermogravimetric analyzer (TGA). DSC method was exploited for determination of phase change temperature, enthalpy, total enthalpy and specific heat (Cp) of DTS and DOS. Thermophysical properties of the produced esters were similar to fatty alcohols. Phase change temperatures and enthalpies were slightly lower than those of pristine fatty alcohols which were explained by the succinate distortion replaced by hydrogen bonding interactions. The DSC analyses pointed out that the phase change temperatures of TDS for heating period were between 47 °C and 46 °C as corresponding enthalpy for cooling period was between 202.4 and 197.5 Jg-1 respectively. The phase change temperature and enthalpy of DOS were between 64 °C and 63 °C and 194.9 and 191.7 Jg-1 respectively. In addition, the thermal cycling test including 1000 accelerated cyclings was conducted to determine the thermal reliability of the synthesized PCMs and structural and thermal consistency of the material were checked by post FT-IR and DSC analysis. Morphology and thermal endurance limits of the DTS and DOS were also investigated using POM and TGA respectively. Based on the results, it was concluded that the synthesized novel PCMs had considerable potential due to their satisfactory thermal properties, thermal reliability and stability.

DETERMINATION OF THERMAL PROPERTIES OF COFFEE BEANS AT DIFFERENT DEGREES OF ROASTING

<p>The aim of this study was to determine the main thermal properties of the granular mass of coffee (specific heat, thermal conductivity, and thermal diffusivity) for different degrees of roasting, as well as to model and simulate thermal conductivity at different degrees of roasting. For determination of specific heat, the mixing method was used, and for thermal conductivity, the theoretically infinite cylinder method with a central heating source. Thermal diffusivity was simulated algebraically using the results of the properties cited above and of the apparent specific mass of the product. Thermal conductivity was also simulated and optimized through finite element analysis software. At darker roasting, there was an increase in specific heat and a reduction in thermal conductivity and thermal diffusivity. Comparing thermal conductivity determined in relation to simulated and optimized conductivity, the mean relative error was 1.02%, on average.</p>

Determination of thermophysical properties of phase change materials using T-History method

Phase change materials (PCM) are known for applications in thermal storage, with capability of absorbing and releasing large amount of energy, when material changes phases from liquid to solid at certain temperatures. As latent heat has gained importance over the years, it is important that there are developed methods to determine properties. In this work T-History method is tested for determination of specific heat of liquid and solid PCM and heat of fusion. Four PCM samples were used, two mixtures of organic PCM and two mixtures of inorganic salts. The results showed that the applied experimental set-up allows to determine heat of fusion which is in good agreement with values stated by manufacturer.

RESEARCH OF THERMAL CHARACTERISTICS OF WILLOW SHOOTS BY DEVICT OF SYNCHRONOUS THERMAL ANALYSIS

The article presents the operation principle of the device DMKI-01 and results of determination of heat capacity and specific heat of evaporation from the tree tissues of oneyear shoots of willow.

Thermal Diffusivity of Methanol to a Pressure of 5 GPa

Thermal diffusivities of methanol have been measured, using transient optical gratings, at 26 °C, up to a pressure of 5 GPa; together with previously reported measurements of thermal effusivities, they are used to estimate values of methanol’s specific heat and thermal conductivity to a pressure of 8 GPa. At lower pressures, the calculated quantities compare favorably with a published equation-of-state and a separate formulation for conductivity. Use of diffusivities in combination with effusivities is of particular interest, as both can be measured with optical techniques applicable to the high-pressure, diamond-anvil cell. Such experiments thus afford an experimental path to the determination of specific heats and thermal conductivities at the high compressions achievable with this experimental tool.

Determination of acoustic fields in acidic suspensions of peanut shell during pretreatment with high-intensity ultrasound

Abstract The benefits of high-intensity ultrasound in diverse processes have stimulated many studies based on biomass pretreatment. In order to improve processes involving ultrasound, a calorimetric method has been widely used to measure the real power absorbed by the material as well as the cavitation effects. Peanut shells, a byproduct of peanut processing, were immersed in acidified aqueous solutions and submitted to an ultrasonic field. Acoustic power absorbed, acoustic intensity and power yield were obtained through specific heat determination and experimental data were modeled in different conditions. Specific heat values ranged from 3537.0 to 4190.6 J·kg-1·K-1, with lower values encountered for more concentrated biomass suspensions. The acoustic power transmitted and acoustic intensity varied linearly with the applied power and quadratically with solids concentration, reaching maximum values at higher applied nominal power and for less concentrated suspensions. A power yield of 82.7% was reached for dilute suspensions at 320 W, while 6.4% efficiency was observed for a concentrated suspension at low input energy (80 W).

Determination of Radial Thermal Conductivity and Specific Heat in Externally-Heated LiCoO2 cells

In this presentation, we will investigate the thermophysical properties of LiCoO2 18650 battery cells. Due to their versatility and high energy density, lithium-ion batteries have become a major power source in a number of consumer and industrial products over the last decade. As their popularity and number of applications increase, so do instances of catastrophic battery failure. Excessive external heating, which in turn leads to thermal runaway, is a principle cause of cell failure and failure events continue to occur despite the installation of safety features, such as vents and thermal fuses, within the cells. Models of cell failure do exist and they have been used to improve upon battery safety features; however, failure models require prior knowledge of the cell’s thermophysical properties. For many common, commercial lithium-ion batteries, LiCoO2 18650 cells included, knowledge of their thermophysical properties is often either incomplete or absent entirely. To determine the radial thermal conductivity and specific heat of a LiCoO2 18650 cell, we conducted external heating experiments and created a numerical heat transfer model. In our experiments, a thermocouple and a heat flux sensor were mounted to the battery surface and, without damaging the cell, external heat was provided using NiCr wire, wrapped helically around the cell’s exterior. Using the time-dependent heat flux data measured at the battery’s surface, our computational model solved the heat conduction equation for the cell’s radial temperature profile. The radial thermal conductivity and specific heat of the LiCoO2 18650 cell were then found by minimizing the difference between the experimental surface temperature data and the model’s predicted surface temperature over time. Matching the model’s results with the experimental data was achieved with a parametric exploration of specific heat values and the Secant Method, which iterated over the radial thermal conductivity. Over the course of our presentation, the experimental setup, the numerical model, and the results we obtained will be explored in detail. We will also discuss how this method can be used to study the radial thermal conductivity and specific heat of any cylindrical cell.

Thermal properties of wood-based panels: specific heat determination

Ensuring reliability of data on thermal properties of wood-based panels is important for manufacturing processes, especially when it is recommended to shorten the cooling phase and stack the panels in hot conditions. Prediction of the heat transfer during cooling phase and normal or hot stacking based on accurate data is essentially important for attaining panels of required properties. The thermal properties are also required when designing houses, especially low-energy or passive ones. Therefore, a water calorimeter was adequately designed and constructed to ensure improvement in the accuracy of the specific heat measurements. The calorimeter was used to determine the specific heat. The attained accuracy estimated by the relative error was significantly increased, and the error values were less than 2 % for all types of the investigated particleboard and OSB. In case of low-density fiberboard (LDF), the maximum value of the relative error did not exceed 4 %. It was also shown that high accuracy required for the specific heat measurements was achieved for experiments in which high-mass samples were used, in contrast to measurements for such samples in traditional DSC systems. The results for the specific heat were within the range from 1420 to 1450 J/kg K for LDF and all types of particleboard. The effect of the investigated material density on the specific heat was not found. The only exception was in case of OSB for which the specific heat was ca. 1550 J/kg K, and it was approximately 100 J/kg K higher when compared to other panels.

Introduction to porous spinel for refractory (high temp) material

Summary The paper examines thermal properties of materials. The transient pulse method was used for specific heat, thermal diffusivity and thermal conductivity determination. Porous MgO was synthesis by heating pellets at 1100 °C for 1 h. The resultant porous MgO was then immersed in 10 mol/L aluminum nitrate solution, dried, and reheated at 1300 °C for 2 h to convert it to spinel. The evaluation was performed with the help of mathematical apparatus used for study of fractal structures properties. The method results from generalized relations that were designed for study of physical properties of fractal structures. As it is shown these relations are in a good agreement with the equations used for the description of time responses of temperature for the pulse input of supplied heat.

Preparation, Characterization and Evaluation in Gasification of Cellulignins Derived from Sugar Cane Bagasse and Rice Husks: Reuse Case of Lignocellulosic Waste

This work describes the production and characterization of cellulignins from vegetable waste, along with an evaluation of their performance in gasification processes. The first part of the project consists in the preparation of cellulignins from sugar cane bagasse and rice husks. The second involves the physicochemical characterization of these cellulignins, including the determination of specific surface area and heat of combustion and the analysis of thermogravimetry curves. The original lignocellulosic precursors are also characterized by proximate analysis, elemental analysis (CHN) and the determination of the contents of cellulose, hemicelluloses, total lignin (soluble and insoluble) and ashes. The prepared and characterized cellulignins are then submitted to the gasification process. The cellulignin gasification produces synthesis gas, which is a mixture of CO , H 2 , CO 2 and CH 4 .T he cellulignin derived from sugarcane bagasse is found to be somewhat more selective for the production of hydrogen.

Synthesis of monoclinicIrTe2under high pressure and its physical properties

In a pressure-temperature (P-T) diagram for synthesizing IrTe2 compounds, the well-studied trigonal (H) phase with the CdI2-type structure is stable at low pressures. The superconducting cubic (C) phase can be synthesized under higher temperatures and pressures. A rhombohedral phase with the crystal structure similar to the C phase can be made at ambient pressure; but the phase contains a high concentration of Ir deficiency. In this paper, we report that a rarely studied monoclinic (M) phase can be stabilized in narrow ranges of pressure and temperature in this P-T diagram. The peculiar crystal structure of the M-IrTe2 eliminates the tendency to form Ir-Ir dimers found in the H phase. The M phase has been fully characterized by structural determination and measurements of electrical resistivity, thermoelectric power, DC magnetization, and specific heat. These physical properties have been compared with those in the H and C phases of Ir1-xTe2. Moreover, magnetic and transport properties and specific heat of the M-IrTe2 can be fully justified by calculations with the density-functional theory presented in this paper.