Erratum to “Confirmation of the First Law of Thermodynamics in Theory and Extended Bernoulli Equation” [Journal of Applied Mathematics and Physics, 11 (2023) 409-420]

Chengshu Jin

College of Food and Pharmaceutical Engineering, Suihua University, Suihua, China.

DOI: 10.4236/jamp.2024.128174                

Abstract

The original online version of this article (Jin, C.S. (2023) Confirmation of the First Law of Thermodynamics in Theory and Extended Bernoulli Equation. Journal of Applied Mathematics and Physics, 11, 409-420. https://doi.org/10.4236/jamp.2023.112023) unfortunately has some errors. The mistakes easily caused some misunderstandings. Therefore, those need some further amendments and clarifications.

Keywords

Erratum

2. Relations of Heat, Work, and Internal Energy Change

2.2. Confirmation the First Law of Thermodynamics in Theory

In any spontaneous or realistic process, we always have [5] [18]

$\text{d}U=C_V\text{d}T$ .(2a)

For a matter in the same phase state, the internal energy change has to be equal to zero in any isothermal process. The Equation (2a) can be derived from the Clausius inequality. The real gases that obey the Equation (2a) had been proven [5]. The ideal gas, real gases, liquids, and solids all obey the Equation (2a) too. According to the Equation (2a), in the isothermal process we have $\text{d}U=C_V\text{d}T=0$ . So that, U has to be a constant (because the differential of constant is equal to zero in mathematics). Where, $U=U_0+{\displaystyle {\int }_i^f{C}_V\text{d}T}$ . The U₀ values for identical matter in the solid, liquid, and gas status are different at the same temperature. U₀ hasn’t any relationship with C_V.

If a matter appears phase transition in the isothermal process, the following equation will be given by

$\Delta U={\displaystyle {\int }_f{C}_V\text{d}T}-{\displaystyle {\int }_i{C}_V\text{d}T}=C\left(f\right)-C\left(i\right)$ ,(2b)

where, i and f express the initial state and final state of a matter in the phase transition, respectively. C(i) and C(f) are all constants.

When the matters occur the variety at the chemical reactions or nuclear reactions in the isothermal process, we can obtain the Equation (2b) too, but i and f express the reactants and products respectively. C(i) and C(f) are all constants too. Hence, ΔU has to be equal to constant or zero in any isothermal process. Then, in the isothermal process, the following equation can be given by

$C\left(f\right)-C\left(i\right)=\Delta H-p\Delta V$ .(2c)

4. Results and Discussion

4.2. Force Diagram of Aircraft

In the extended or modified Bernoulli equations, $\Delta E_{kin}$ and $\Delta {E^{\prime }}_{kin}$ are all equal to ${\displaystyle {\int }_i^{f}m\upsilon \text{d}\upsilon }$ or ${\displaystyle \sum _i^{f}m\upsilon \text{d}\upsilon }$ , ${\displaystyle {\int }_i^{f}V\text{d}p}={\displaystyle \sum _i^{f}V\text{d}p}$ , ${\displaystyle {\int }_i^{f}Sh\text{d}p}={\displaystyle \sum _i^{f}Sh\text{d}p}$ for the constant volume process, ${\displaystyle {\int }_i^{f}mg\text{d}{H}_e}={\displaystyle \sum _i^{f}mg\text{d}{H}_e}$ , ${\displaystyle {\int }_i^{f}mg\text{d}{H}_f}={\displaystyle \sum _i^{f}mg\text{d}{H}_f}$ , and ${\displaystyle {\int }_i^{f}mg\text{d}h}={\displaystyle \sum _i^{f}mg\text{d}h}\approx {\displaystyle {\int }_i^f{G}_0\frac{m\cdot m_0}{{\left(r_0+h\right)}^2}\text{d}h}={\displaystyle \sum _i^f{G}_0\frac{m\cdot m_0}{{\left(r_0+h\right)}^2}\text{d}h}$ , where, υ expresses velocity, m₀ is the mass of earth, r₀ is the radius of earth, G₀ is the gravitational constant, g is the acceleration of gravity, h is the elevation. ∑ is summation symbol. Attentively, g isn’t constant.

According to Boltzmann density distribution equation for the atmosphere, we can obtain an approximate equation as $h=-\frac{kT}{Mg}\ln \frac{p}{p_0}$ , where, M is mass of air molecule, k is Boltzmann constant, p is equal to p₀ when h = 0. Attentively, ln expresses natural logarithm symbol. The right Boltzmann density distribution equation for the atmosphere should be $p=p_0{\text{e}}^{-\frac{G_{0}M\cdot m_{0}h}{kT\left(r_0+h\right)r_0}}$ .

Conflicts of Interest

The author declares no conflicts of interest regarding the publication of this paper.

References