scholarly journals Proposal for determining changes in entropy of semi ideal gas using mean values of temperature functions

2014 ◽  
Vol 68 (5) ◽  
pp. 615-628 ◽  
Author(s):  
Branko Pejovic ◽  
Vladan Micic ◽  
Mitar Perusic ◽  
Goran Tadic ◽  
Ljubica Vasiljevic ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Internal Energy ◽  
Temperature Interval ◽  
Specific Heat Capacity ◽  
Mean Value ◽  
Ideal Gas ◽  
Mean Values ◽  
Arbitrary Temperature ◽  
The Mean

In a semi-ideal gas, entropy changes cannot be determined through the medium specific heat capacity in a manner as determined by the change of internal energy and enthalpy, i.e. the amount of heat exchanged. Taking this into account, the authors conducted two models through which it is possible to determine the change in the specific entropy of a semi-ideal gas for arbitrary temperature interval using the spread sheet method, using the mean values of the appropriate functions. The idea is to replace integration, which occurs here in evitably, with mean values of the previous functions. The models are derived based on the functional dependence of the actual specific heat capacity on the temperature. The theorem used is that of the mean value of a function as well as the mathematical properties of the definite integral. The mean value of a fractional function is determined via its integrand while the logarithmic functions were performed by applying a suitable transformation of the differential calculus. The relations derived relation, using the computer program, have enabled the design of appropriate thermodynamic tables through which it is possible to determine the change in entropy of arbitrary state changes in an efficient and rational manner, without the use of calculus or finished forms. In this way, the change in the entropy of a semi-ideal gas is determined for an arbitrary temperature interval using the method which is analogous to that applied in determining the change of internal energy and enthalpy or the amount of heat exchanged, which was the goal of the work. Verification of the proposed method for both the above functions was performed for a a few characteristic semi-ideal gases where change c(T) is significant, for the three adopted temperature intervals, for the characteristic change of state. This was compared to the results of the classical integral and the proposed method through the prepared tables. In certain or special cases, it is possible to apply the presented method also in determining the change in entropy of the real gas. Apart from that, the paper shows that the change in entropy for the observed characteristic case can be represented or graphically determined using the planimetric method of diagrams with suitably selected coordinates.

scholarly journals Evaluation of Properties of Composite Panels Fabricated from Waste Newspaper and Wood Dust for Structural Application

2020 ◽  
pp. 8-15
Author(s):  
Ekong Ufot Nathaniel ◽  
Ubong Williams Robert ◽  
Mercy Effiong Asuquo
Keyword(s):  
Heat Capacity ◽  
Flexural Strength ◽  
Specific Heat ◽  
Bulk Density ◽  
Specific Heat Capacity ◽  
Treated Wood ◽  
Untreated Wood ◽  
Wood Dust ◽  
Mean Values ◽  
The Mean

In this work, dry forms of waste newspaper pulp, untreated wood dust and treated wood dust were used at varying weight proportions to fabricate composite panels which thenafter served as test samples. With increase in the content of either the untreated wood dust or the treated wood dust in the developed panels, the results showed increase in the mean values of bulk density, thermal conductivity, thermal diffusivity, flexural strength but decrease in the mean values of specific heat capacity and percentage water absorption. Also, at p < 0.05, significant differences were revealed in the mean values of bulk density and specific heat capacity between the results obtained for samples with untreated wood dust content and those associated with samples containing the treated wood dust. Again, samples containing the untreated wood dust were found to be better thermal insulators but with lower flexural strength than those of same proportions of the treated wood dust component. From application viewpoint, the findings in this work indicated that the fabricated samples could compete favorably with conventional materials commonly used for thermal insulation in buildings. It is, therefore, obvious that recycling waste newspaper and wood dust into such panels can help to reduce the adverse effect of the waste materials on environment also improve economy by providing building sector with low-cost and environmentally-friendly insulation materials suitable for internal building design.

INDIRECT MEASUREMENT OF Zn-DOPED In2S3 NANOFILMS' SPECIFIC HEAT CAPACITY

2008 ◽  
Vol 07 (04n05) ◽  
pp. 229-233 ◽  
Author(s):  
S. LAZZEZ ◽  
K. BOUBAKER BEN MAHMOUD ◽  
M. AMLOUK
Keyword(s):  
Heat Capacity ◽  
Electron Microscope ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Room Temperature ◽  
Thermal Analyses ◽  
Indirect Measurement ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Mean

ZnIn 2 S 4 nanofilms were grown on In 2 S 3 substrates. The band gap of ZnIn 2 S 4 barriers was approximately 2.8 eV at room temperature. The morphology and structure of the obtained nanofilms were already investigated via transmission electron microscope (TEM), scanning electron microscope (SEM) and X-ray diffraction analyses.1,2 In this paper, thermal analyses are performed via a photothermal technique, which has been used to indirectly evaluate the specific heat capacity of the obtained Zn -doped nanofilms. The yielded value for an optimal zinc-to-indium ratio, x (0.33), at the mean room temperature (T∞ = 301 K ), was Cs ≈ 411.5 J K -1 kg -1.

FALSIFICATIONS OF POISSON ADIABATE, HUGONIO ADIABATE, LAPLACE SOUND SPEEDS. MODERNIZATION OF FOUNDATIONS OF THERMODYNAMICS

2020 ◽  
Vol 5 (333) ◽  
pp. 58-67
Author(s):  
K.B. Jakupov ◽  
Keyword(s):  
Shock Wave ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Speed Of Sound ◽  
Constant Pressure ◽  
Energy Balance Equation ◽  
Ideal Gas ◽  
Constant Volume ◽  
Capacity Coefficient

The inequality of the universal gas constant of the difference in the heat capacity of a gas at constant pressure with the heat capacity of a gas at a constant volume is proved. The falsifications of using the heat capacity of a gas at constant pressure, false enthalpy, Poisson adiabat, Laplace sound speed, Hugoniot adiabat, based on the use of the false equality of the universal gas constant difference in the heat capacity of a gas at constant pressure with the heat capacity of a gas at a constant volume, have been established. The dependence of pressure on temperature in an adiabatic gas with heat capacity at constant volume has been established. On the basis of the heat capacity of a gas at a constant volume, new formulas are derived: the adiabats of an ideal gas, the speed of sound, and the adiabats on a shock wave. The variability of pressure in the field of gravity is proved and it is indicated that the use of the specific coefficient of ideal gas at constant pressure in gas-dynamic formulas is pointless. It is shown that the false “basic formula of thermodynamics” implies the falseness of the equation with the specific heat capacity at constant pressure. New formulas are given for the adiabat of an ideal gas, adiabat on a shock wave, and the speed of sound, which, in principle, do not contain the coefficient of the specific heat capacity of a gas at constant pressure. It is shown that the well-known equation of heat conductivity with the gas heat capacity coefficient at constant pressure contradicts the basic energy balance equation with the gas heat capacity coefficient at constant volume.

Evaluation of Specific Heat Capacity and Entropy of Particle Bound Harmonics Oscillator Cosine Asymmetric Potential by Partition Function

2019 ◽  
Vol 886 ◽  
pp. 194-200
Author(s):  
Piyarut Moonsri ◽  
Artit Hutem
Keyword(s):  
Heat Capacity ◽  
Quantum Mechanics ◽  
Partition Function ◽  
Specific Heat ◽  
Internal Energy ◽  
Specific Heat Capacity ◽  
Function Method ◽  
Bound State ◽  
State Problem ◽  
Bound State Problem

In this research, a fundamental quantum mechanics and statistical mechanic bound-state problem of harmonics oscillator cosine asymmetric was considered by using partition function method. From the study, it found that the internal energy, the entropy and the specific heat capacity of particle vibration bound-state under harmonics oscillator cosine asymmetric potential were increased as the increasing of the parameters of μ, η, and β. While an increasing of parameter α affected to the decreasing of the entropy and the heat capacity. In addition, the increasing values of the entropy and the specific heat capacity value were depended on the decreasing of the parameter α value.

scholarly journals Uncertainty estimation of the mean specific heat capacity for the major gases contained in biogas

2020 ◽  
Vol 66 (No. 2) ◽  
pp. 52-59
Author(s):  
Petr Travnicek ◽  
Ivan Vitázek
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Scientific Work ◽  
Uncertainty Estimation ◽  
Simple Arithmetic ◽  
Capacity Calculation ◽  
The Mean ◽  
Specific Heat Capacities ◽  
The Individual

The paper is focused on the uncertainty estimation of the mean isobaric and isochoric specific heat capacity calculation. The differences in the data among the individual sources for the technical calculation are presented in the first part of the paper. These differences are discussed in this paper. Research of scientific work with listed values of measurement uncertainties has been carried out in the second part of the paper. Furthermore, mathematical models were calculated which describe the dependence of the specific heat capacities and temperature. The maximal error models were carried out. Two approaches were used for the calculation of the mean specific heat capacity. The first approach is the calculation with help of integration of the function which describes the dependence of the specific heat capacity and temperature. The second approach is the calculation of a simple arithmetic mean of the specific heat capacity related to the maximal and minimal value of the temperature interval. The conclusion of the work shows that the time-effective second way is applicable in the case of a narrow temperature range. A value of 5.5% (Δ<sub>t</sub> = 200 K) was reached for the relative uncertainty. This is a similar value to that in the case of using the first way.

scholarly journals The Important Thermal Characteristics of Matter and Their Computations with the Use of the Gibbs Potentials

2019 ◽  
Vol 19 (2) ◽  
pp. 134-138
Author(s):  
Y. S. Budzhak ◽  
T. Wacławski
Keyword(s):  
Heat Capacity ◽  
Free Energy ◽  
Specific Heat ◽  
Internal Energy ◽  
Gibbs Free Energy ◽  
Specific Heat Capacity ◽  
Thermodynamic Functions ◽  
Thermodynamic Potential ◽  
Thermal Characteristics ◽  
Dynamic Potential

In this paper, the important thermal characteristics of matter  (they describe thermodynamic systems in a state of thermodynamic equilibrium) were calculated.  There are the following  important thermodynamic functions:   the system   internal energy ,  the thermal function (or enthalpy)   the  free  Helmholtz energy, the thermo-dynamic potential  (or Gibbs free energy), the Gibbs grand thermodynamic potential , the entropy ,  the specific heat capacity . These functions are explicit functions of system’s parameters, they fulfil some mathe-matical relationships  and posses   some total differentials. These  functions  are calculated  in this paper and their physical sense is given in the cited works.

Seasonal trends in the stable isotopic composition of snow and meltwater runoff in a subarctic catchment at Okstindan, Norway

2004 ◽  
Vol 35 (2) ◽  
pp. 119-137 ◽  
Author(s):  
S.D. Gurney ◽  
D.S.L. Lawrence
Keyword(s):  
Isotopic Composition ◽  
Mean Value ◽  
Mean Values ◽  
Stable Isotopic Composition ◽  
Meltwater Runoff ◽  
Stable Isotopic ◽  
The Mean ◽  
The Difference ◽  
Δ18o And Δd

Seasonal variations in the stable isotopic composition of snow and meltwater were investigated in a sub-arctic, mountainous, but non-glacial, catchment at Okstindan in northern Norway based on analyses of δ18O and δD. Samples were collected during four field periods (August 1998; April 1999; June 1999 and August 1999) at three sites lying on an altitudinal transect (740–970 m a.s.l.). Snowpack data display an increase in the mean values of δ18O (increasing from a mean value of −13.51 to −11.49‰ between April and August), as well as a decrease in variability through the melt period. Comparison with a regional meteoric water line indicates that the slope of the δ18O–δD line for the snowpacks decreases over the same period, dropping from 7.49 to approximately 6.2.This change points to the role of evaporation in snowpack ablation and is confirmed by the vertical profile of deuterium excess. Snowpack seepage data, although limited, also suggest reduced values of δD, as might be associated with local evaporation during meltwater generation. In general, meltwaters were depleted in δ18O relative to the source snowpack at the peak of the melt (June), but later in the year (August) the difference between the two was not statistically significant. The diurnal pattern of isotopic composition indicates that the most depleted meltwaters coincide with the peak in temperature and, hence, meltwater production.

Experimental Study on the Specific Heat Capacity Measurement of Water-Based Al2O3-Cu Hybrid Nanofluid by using Differential Thermal Analysis Method

2019 ◽  
Vol 15 ◽  
Author(s):  
Andaç Batur Çolak ◽  
Oğuzhan Yıldız ◽  
Mustafa Bayrak ◽  
Ali Celen ◽  
Ahmet Selim Dalkılıç ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermophysical Properties ◽  
Volume Concentration ◽  
Pure Water ◽  
Heat Capacity Measurement ◽  
Experimental Results ◽  
Hybrid Nanofluid ◽  
Capacity Measurement

Background: Researchers working in the field of nanofluid have done many studies on the thermophysical properties of nanofluids. Among these studies, the number of studies on specific heat are rather limited. In the study of the heat transfer performance of nanofluids, it is necessary to increase the number of specific heat studies, whose subject is one of the important thermophysical properties. Objective: The authors aimed to measure the specific heat values of Al2O3/water, Cu/water nanofluids and Al2O3-Cu/water hybrid nanofluids using the DTA method, and compare the results with those frequently used in the literature. In addition, this study focuses on the effect of temperature and volume concentration on specific heat. Method: The two-step method was used in the preparation of nanofluids. The pure water selected as the base fluid was mixed with the Al2O3 and Cu nanoparticles and Arabic Gum as the surfactant, firstly mixed in the magnetic stirrer for half an hour. It was then homogenized for 6 hours in the ultrasonic homogenizer. Results: After the experiments, the specific heat of nanofluids and hybrid nanofluid were compared and the temperature and volume concentration of specific heat were investigated. Then, the experimental results obtained for all three fluids were compared with the two frequently used correlations in the literature. Conclusion: Specific heat capacity increased with increasing temperature, and decreased with increasing volume concentration for three tested nanofluids. Cu/water has the lowest specific heat capacity among all tested fluids. Experimental specific heat capacity measurement results are compared by using the models developed by Pak and Cho and Xuan and Roetzel. According to experimental results, these correlations can predict experimental results within the range of ±1%.

Development of the room temperature protocol based on room temperature ionic liquids and surfactant ionic liquids for the synthesis of derivatives of 2-amino-thiazoles and thermo-physical analysis of the synthesized derivatives using TGA-DSC.

2020 ◽  
Vol 10 ◽  
Author(s):  
Chandrakant Sarode ◽  
Sachin Yeole ◽  
Ganesh Chaudhari ◽  
Govinda Waghulde ◽  
Gaurav Gupta
Keyword(s):  
Thermal Analysis ◽  
Heat Capacity ◽  
Ionic Liquids ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Room Temperature ◽  
Heat Capacity Data ◽  
General Strategy ◽  
Capacity Data ◽  
Derivatives Of

Aims: To develop an efficient protocol, which involves an elegant exploration of the catalytic potential of both the room temperature and surfactant ionic liquids towards the synthesis of biologically important derivatives of 2-aminothiazole. Objective: Specific heat capacity data as a function of temperature for the synthesized 2- aminothiazole derivatives has been advanced by exploring their thermal profiles. Method: The thermal gravimetry analysis and differential scanning calorimetry techniques are used systematically. Results: The present strategy could prove to be a useful general strategy for researchers working in the field of surfactants and surfactant based ionic liquids towards their exploration in organic synthesis. In addition to that, effect of electronic parameters on the melting temperature of the corresponding 2-aminothiazole has been demonstrated with the help of thermal analysis. Specific heat capacity data as a function of temperature for the synthesized 2-aminothiazole derivatives has also been reported. Conclusion: Melting behavior of the synthesized 2-aminothiazole derivatives is to be described on the basis of electronic effects with the help of thermal analysis. Additionally, the specific heat capacity data can be helpful to the chemists, those are engaged in chemical modelling as well as docking studies. Furthermore, the data also helps to determine valuable thermodynamic parameters such as entropy and enthalpy.

scholarly journals Influence of alkaline modification on selected properties of banana fiber paperbricks

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abayomi A. Akinwande ◽  
Adeolu A. Adediran ◽  
Oluwatosin A. Balogun ◽  
Oluwaseyi S. Olusoju ◽  
Olanrewaju S. Adesina
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Moisture Absorption ◽  
Water Volume ◽  
Banana Fiber ◽  
Fiber Loading ◽  
Banana Fibers ◽  
Alkaline Modification

AbstractIn a bid to develop paper bricks as alternative masonry units, unmodified banana fibers (UMBF) and alkaline (1 Molar aqueous sodium hydroxide) modified banana fibers (AMBF), fine sand, and ordinary Portland cement were blended with waste paper pulp. The fibers were introduced in varying proportions of 0, 0.5, 1.0 1.5, 2.0, and 2.5 wt% (by weight of the pulp) and curing was done for 28 and 56 days. Properties such as water and moisture absorption, compressive, flexural, and splitting tensile strengths, thermal conductivity, and specific heat capacity were appraised. The outcome of the examinations carried out revealed that water absorption rose with fiber loading while AMBF reinforced samples absorbed lesser water volume than UMBF reinforced samples; a feat occasioned by alkaline treatment of banana fiber. Moisture absorption increased with paper bricks doped with UMBF, while in the case of AMBF-paper bricks, property value was noted to depreciate with increment in AMBF proportion. Fiber loading resulted in improvement of compressive, flexural, and splitting tensile strengths and it was noted that AMBF reinforced samples performed better. The result of the thermal test showed that incorporation of UMBF led to depreciation in thermal conductivity while AMBF infusion in the bricks initiated increment in value. Opposite behaviour was observed for specific heat capacity as UMBF enhanced heat capacity while AMBF led to depreciation. Experimental trend analysis carried out indicates that curing length and alkaline modification of fiber were effective in maximizing the properties of paperbricks for masonry construction.

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