First Law Of Thermodynamics Research Articles

Assessing energy and environmental impacts of Turkish-style tea brewing: efficiency, consumption, and carbon footprint

Energy efficiency in food preparation is a critical yet often overlooked aspect of sustainability. Despite tea being one of the most consumed beverages worldwide, research on the energy efficiency of its brewing process—particularly at the household level—remains limited. This study addresses this gap by investigating the energy cost, efficiency, and environmental footprint of Turkish-style tea brewing, a method characterized by its unique double teapot system and prolonged steeping process. Experimental tests were conducted on a standard kitchen stove using three burner sizes and varying flame modes. Energy efficiency, analyzed using the First Law of Thermodynamics, ranged from 31% to 70%, with specific energy consumption between 0.53 and 0.93 kJ/kg. Results reveal a trade-off between energy efficiency and brewing time, highlighting the need for optimized techniques to reduce energy waste. Given the massive global tea consumption, this study provides valuable insights for future research on sustainable and energy-efficient food preparation practices.

Energy evolution and damage constitutive model for deep marble under triaxial compression

IntroductionHigh ground stress in deep mining operations results in rocks exhibiting mechanical properties that differ from those at shallow depths. This study conducted conventional triaxial compression (CTC) tests to elucidate themechanical behaviors of deep marble under CTC conditions.MethodsInitially, it analyzed energy evolution of deep marble under CTC conditions and developed a damage variable (D) expression. Subsequently, we examined impacts of confining pressure (σ3) and D on dissipated energy (Wd) and Poisson’s ratio (μ′) and proposed an expression for damage energy dissipation rate (U). Finally, based on the first law of thermodynamics, we established a differential equation for energy balance that facilitated the development of a damage constitutive model (DCM) for marble under CTC conditions. This model effectively couples the internal energy and damage within the rock.ResultsThe results indicated that: (1) the maximum Wd increased with increasing σ3, and the Wd experienced stages of stability, slow growth, steady growth, and slowdown. (2) At a constant σ3, the μ′ under loading conditions increased with increasing damage level. However, as rock damage intensified in the residual stage, the growth rate of μ′ slowed and subsequently stabilized. (3) The proposed model effectively captures the nonlinear characteristics of stress-strain (SS) curves for deep marble under CTC conditions during the elastic, plastic yield, instability failure, and residual stages.DiscussionThis research offers theoretical insights for stability analysis in deep mining activities.

Quantum gravity corrections to the thermodynamics of noncommutative regular black holes

This study explores the quantum gravity effects on the thermodynamics of noncommutative Schwarzschild black holes (NSBH), focusing on entropy. Using a modified first law of thermodynamics, we derive entropy consistent with the Bekenstein–Hawking area law and investigate quantum corrections through the generalized uncertainty principle and tunneling methods.

Hawking–Rényi black hole thermodynamics, Kiselev solution, and cosmic censorship

Abstract Explicit example, where the Hawking temperature of a black hole horizon is compatible with the black hole’s Rényi entropy thermodynamic description, is constructed. It is shown that for every static, spherically symmetric, vacuum black hole space-time, a corresponding black hole solution can be derived, where the Hawking temperature is identical with the Rényi temperature, i.e. the one obtained from the Rényi entropy of the black hole via the 1st law of thermodynamics. In order to have this Hawking–Rényi type thermodynamic property, the black holes must be surrounded by an anisotropic fluid in the form of a Kiselev metric, where the properties of the fluid are uniquely determined by the mass of the black hole, M, and the Rényi parameter, $$\lambda $$ λ . In the simplest Schwarzschild scenario, the system is found to be thermodynamically unstable, and the 3rd law of thermodynamics seems to play the role of a cosmic censor via placing an upper bound on the black hole’s mass, by which preventing the black hole from loosing its horizon(s).

Integration of Energy Conservation Principles Across Mechanical Engineering Curriculum: Updates on A Work-in-Progress Project

This ongoing project, now in its fourth year, strengthens the integration of energy conservation principles within the undergraduate mechanical engineering curriculum, with a specific focus on heat exchangers. Building upon previous efforts, this phase emphasizes both theoretical understanding and practical application of energy transfer and efficiency. Students’ progress through Thermodynamics, Fluid Mechanics, and Heat Transfer courses, reinforcing the First Law of Thermodynamics and its application to energy balance equations governing heat exchangers. This year, the project introduced a dedicated heat exchanger lab component, where students conduct experiments to validate theoretical calculations and observe real-world energy transfer phenomena. Additionally, computational work using simulation software allows students to model and analyze complex heat exchanger designs, exploring the impact of various parameters on performance. Direct and indirect evaluations, including problem-solving exercises, lab reports, computational analyses, and surveys, assess conceptual mastery and practical application skills. Preliminary results indicate that the combined approach of theoretical instruction, hands-on experimentation, and computational modeling significantly enhances student comprehension and retention of energy conservation principles as applied to heat exchangers. This presentation details the progress and findings of this phase, building upon presentations at previous WVAS meetings, and demonstrates how this project refines engineering education by equipping students with the tools to address complex thermal system challenges.

Temperature rise and suspension dynamic characteristics of semi-active hydro-pneumatic suspension based on thermodynamics and heat transfer

The temperature of the oil has a decisive impact on the vehicle’s dynamics as it significantly affects the viscosity, influencing the damping force of the hydro-pneumatic suspension (HPS), and subsequently affecting the dynamics of the suspension. Therefore, this paper proposes a more accurate semi-active HPS model to investigate the HPS temperature rise characteristics through thermodynamics and heat transfer. According to the flow equation of small holes, flow models for normally open holes, check valves and solenoid valves were established by combining the viscosity-temperature equation of the oil and the conservation law of mass, HPS thermodynamic model reflecting the viscosity-temperature characteristics was deduced. The real gas equation of state, the Redlich–Kwong (R-K) equation, was used to model the elastic forces of nitrogen. Besides, based on the first law of thermodynamics, combined with the differential equation of internal energy, Newton’s cooling equation, and Fourier’s law, models of semi-active HPS heat transfer and heat transfer coefficients were constructed, with nitrogen, oil, and cylinder being respectively taken as the objects of study. Combining the suspension thermodynamic model and heat transfer model, MATLAB was utilized to solve the variation of suspension nitrogen and oil temperatures over time under sinusoidal excitation at different frequencies, amplitudes, and currents. The results show that the temperatures of the oil and nitrogen eventually stabilize, reaching thermal equilibrium, with the oil temperature consistently higher than that of the nitrogen. Furthermore, the results also demonstrate that the increased excitation frequency and amplitude, as well as decreased current significantly raise the thermal equilibrium temperatures of oil and gas. The elastic and damping characteristic curves of the suspension at different temperatures demonstrate that as the temperature increases, the damping force provided by the suspension decreases, and elastic forces increase.

Moving body relativistic entropy variations

Abstract A formalism based on a four-vector fundamental equation is used to derive the equations governing mechanics and thermodynamics of a process, the absorption of laser photons by a blackbody in an adiabatic process, and the body entropy variations observed from two reference frames in the standard configuration. The classical (Clausius) definition of entropy variations, dS = δQ rv/T (Q rv stands for heat exchanged in a reversible process), is generalised as d S ˆ = ∥ d E ˆ pN μ ∥ / T , with ∥ d E ˆ pN μ ∥ the norm of the four-vector associated to the set of thermal phonons exchanged in frame K ˆ as heat between the blackbody and the thermal reservoir. This relativistic formalism addresses the so-called Ott-Planck imbroglio, arising from the transformation of thermodynamic equations, such as the first law of thermodynamics, and related variables, including temperature, heat and entropy, within the framework of Einstein’s special theory of relativity.

On the first law of thermodynamics for open systems

On the first law of thermodynamics for open systems

Energy rate balance applied to coastal engineering problems by using RANS-VoF models in numerical wave flumes

Energy rate balance applied to coastal engineering problems by using RANS-VoF models in numerical wave flumes

Thermodynamics of Schwarzschild-AdS black hole in non-commutative geometry

In this paper, we study the thermodynamics of Schwarzschild-anti-de Sitter black holes within the framework of non-commutative geometry. By solving the Einstein equation, we derive the corrected Schwarzschild-AdS black hole with Lorentzian distribution and analyze the thermodynamics. Our results confirm that if the energy-momentum tensor outside the event horizon is related to the mass of the black hole, the conventional first law of thermodynamics will be violated. The study of criticality reveals that the black hole undergoes a small black hole-large black hole phase transition similar to that of the Van der Waals system, with a critical point and critical ratio slightly smaller than that of the Van der Waals fluid. As the non-commutative parameter increases, the phase transition process shortens, leading to a critical point, and ultimately to the disappearance of the phase transition. The violation of the conventional first law results in a discontinuity of the Gibbs free energy during the phase transition, indicating the occurrence of zeroth-order phase transition. Moreover, we investigate the Joule-Thomson expansion, obtaining the minimum inversion temperature and minimum inversion mass.

Study on the change rule of airflow temperature field in ultra-deep mining shaft

In the background of increasing depth of metal mining, the issue of airflow temperature field during the construction of ultra-deep shaft is very important, in view of the fact that there is still very little research related to this content at home and abroad, so this aspect of the research is very necessary in the process of the development of deep shaft mining. This paper focuses on the study of the patterns of change in the airflow temperature field during the construction of ultra-deep shaft, based on Newton’s law of cooling and the first law of thermodynamics, and from the perspective of fluid dynamics, it puts forward a new theory - the theory of equilibrium enthalpy interface, which qualitatively and quantitatively derives the critical conditions of the three changes in the wind temperature of ultra-deep shaft and uses numerical simulation to study the content of the theory. The results of the study show that when the airflow runs from bottom up in the ultra-deep shaft, the change of airflow temperature is not a simple linear relationship, but a curve relationship similar to a cubic function, showing a law of decreasing first, then increasing and then decreasing. In addition, the equilibrium enthalpy interface theory elucidates the energy conversion relationship and process behind the change law of the airflow temperature field in the ultra-deep shaft. This study has explored the theoretical aspects of the airflow temperature field during the construction period of ultra-deep shaft, and also laid the foundation for the subsequent ventilation and cooling work of shaft construction.

How to violate the first law of thermodynamics with an ASE of Papain and Newcomen before it was stated by Clausius

This paper explores the historical and thermodynamic implications of the atmospheric steam engines (ASE) developed by Denis Papin and Thomas Newcomen in the late 17th and early 18th centuries. These engines, which operated using vacuum-induced contraction rather than steam expansion, seemingly violated the first law of thermodynamics—conservation of energy—before it was formally articulated by Rudolf Clausius in the mid-19th century. Papin's innovative approach utilized thermal contraction and atmospheric pressure to perform mechanical work, a method later refined by Newcomen. The engines achieved work through vacuum generation by condensing steam with cold water, a process that contradicted the conventional understanding of energy conservation as later defined by Clausius and Carnot. The paper analyzes the operational principles of Papin’s and Newcomen’s ASEs, highlighting how their contraction-based work led to an increase in internal energy while performing useful mechanical work, a phenomenon inconsistent with the first law of thermodynamics. The study also examines the transition from contraction-based engines to expansion-based systems, such as the Rankine cycle, and discusses the implications of these early engines on the development of thermodynamic theory. Through case studies and experimental evidence, the paper argues that the first law, as originally stated, fails to account for contraction-based work, suggesting a need for its revision to include such phenomena. The findings underscore the historical significance of Papin’s and Newcomen’s contributions to engineering and thermodynamics, while also raising questions about the completeness of classical thermodynamic principles.

Measurement of gas exchange surface area from DLNO and DLCO.

Measurement of gas exchange surface area from DLNO and DLCO.

Optical features and thermal properties of charged AdS Euler–Heisenberg black hole surrounded by perfect fluid dark matter

In this article, motivated by the high interest in Euler–Heisenberg nonlinear electrodynamic theory, we investigated several thermal aspects of the charged Euler–Heisenberg black hole surrounded by perfect fluid dark matter. To ensure the validity of the first law of thermodynamics, we measured the conserved thermal quantities. Furthermore, the local and global thermal stability of the charged Euler–Heisenberg black hole surrounded by perfect fluid dark matter is also discussed in canonical and grand canonical ensembles and reveals how the coupling parameter affects the stability regions. We also examined the extended second-order phase transition via P–V criticality. Finally, we extend our study to the optical features of the charged Euler–Heisenberg black hole surrounded by perfect fluid dark matter, such as the black hole shadow and energy emission rate and observe the impact of the coupling parameter.

When Bohr got it wrong

Philip Ball peers into the quantum past, and uncovers a little-known paper published by Niels Bohr, Hendrik Kramers and John Slater in 1924, that proposed that the first law of thermodynamics may no longer hold firm. Their idea turned out to be wrong, but in interesting and provocative ways, and it demonstrates the intense turmoil in physics on the brink of quantum mechanics.

Energy and Economical Analysis of Drying Process of Domestic Wastewater Treatment Sludge with Heat Pump

In this study, a heat pump was designed to dry the sludge produced by a wastewater treatment plant. The purpose of drying the sludge is to convert it into raw material as fuel pellets, which can provide some or all of the energy needed by the treatment plant. The design of the heat pump considered the plant's production capacity and sludge generation rate. All thermal analyses were carried out according to the First Law of Thermodynamics. The heat pump system performances are investigated by using Danfoss Coolselector 2.0 program. The capacities of the heat pump components were calculated for different refrigerants and performance coefficients. The highest coefficient of performance (CoP) was found to be 5.99 for R1234zeE in summer, while the lowest was 2.33 for R134a. If the sludge is burned as biofuel, theoretically it was estimated that the energy production could range from 723,000 kWh/month to 744,000 kWh/month for the R407c and R1234zeE refrigerants respectively. The economic analysis showed that the system's payback period could range from 1.9 to 6.5 years.

The information conservation in Hawking radiation by laws of thermodynamics

By solving the field equation in curved spacetime, we obtained the relative emissivity of the Kerr–Newman black hole. The results show that the relative emissivity satisfies the Boltzmann distribution law. With the first law of thermodynamics, we found that the emissivity is related to the entropy change of black holes which helps us solve the information loss in the Hawking radiation. Through calculating the information entropy of black holes, it is shown that the information conservation is satisfied in the Hawking radiation. Furthermore, we also studied the contribution of space-time background to Hawking radiation.

Holographic thermodynamic relation for dissipative and non-dissipative universes in a flat FLRW cosmology

Horizon thermodynamics and cosmological equations in standard cosmology provide a holographic-like connection between thermodynamic quantities on a cosmological horizon and in the bulk. It is expected that this connection can be modified as a holographic-like thermodynamic relation for dissipative and non-dissipative universes whose Hubble volume V varies with time t. To clarify such a modified thermodynamic relation, the present study applies a general formulation for cosmological equations in a flat Friedmann–Lemaître–Robertson–Walker (FLRW) universe to the first law of thermodynamics, using the Bekenstein–Hawking entropy SBH and a dynamical Kodama–Hayward temperature TKH. For the general formulation, both an effective pressure pe of cosmological fluids for dissipative universes (e.g., bulk viscous cosmology) and an extra driving term fΛ(t) for non-dissipative universes (e.g., time-varying Λ(t) cosmology) are phenomenologically assumed. A modified thermodynamic relation is derived by applying the general formulation to the first law, which includes both pe and an additional time-derivative term f˙Λ(t), related to a non-zero term of the general continuity equation. When fΛ(t) is constant, the modified thermodynamic relation is equivalent to the formulation of the first law in standard cosmology. One side of this modified relation describes thermodynamic quantities in the bulk and can be divided into two time-derivative terms, namely ρ˙ and V˙ terms, where ρ is the mass density of cosmological fluids. Using the Gibbons–Hawking temperature TGH, the other side of this relation, TKHS˙BH, can be formulated as the sum of TGHS˙BH and [(TKH/TGH)-1]TGHS˙BH, which are equivalent to the ρ˙ and V˙ terms, respectively, with the magnitude of the V˙ term being proportional to the square of the ρ˙ term. In addition, the modified thermodynamic relation for constant fΛ(t) is examined by applying the equipartition law of energy on the horizon. This modified thermodynamic relation reduces to a kind of extended holographic-like connection when a constant TKH universe (whose Hubble volume varies with time) is considered. The evolution of thermodynamic quantities is also discussed, using a constant TKH model, extending a previous analysis (Komatsu in Phys Rev D 108:083515, 2023).

Density Functional Study on the Condensation and Evaporation Heats of the Nanoconfined Fluids.

Within the framework of classical density functional theory, the isosteric heat and condensation/evaporation heat of the confined methane are studied. First, the theoretical expression for condensation/evaporation heat is derived on the basis of the first law of thermodynamics. The method for computation is also proposed. With the proposed method, the dependences of the condensation/evaporation heat on temperature, pore width, and surface strength are studied and analyzed in detail. First of all, it is found that the condensation/evaporation heat of the confined fluid decreases monotonically with the temperature. Moreover, it is also found that at the same temperature the condensation heat is usually larger than the corresponding evaporation heat, which confirms the irreversibility of the condensation and evaporation from an exothermic point of view. Furthermore, our results reveal that the condensation/evaporation heat of confined fluid in pores decreases with the width of the pore. With the further increase in the pore width, the condensation/evaporation heat tends gradually to that of the corresponding bulk fluids. In addition, an interesting result is found that the condensation/evaporation heat is insensitive to variation in surface strength.

Constructing an Entropy-Force Model of the Expansion of the Universe due to Gravitationally Induced Production of Dark Matter

In the framework of entropic cosmology and Prigozhin’s gravitational theory about the connection between geometry and matter, providing the production of particles in the cosmological fluid, as well as in the assumption of exchange entropy at the event horizon, a one-liquid model of the evolution of a spatially flat, homogeneous and isotropic Universe is constructed. For its construction the energy conservation equation is derived from the first law of thermodynamics taking into account gravitationally induced creation of matter and exchange energy processes on the visible horizon of the Universe. On the basis of the energy equation and the fundamental Friedman equation describing the expansion of the Universe, modified Friedman-Robertson-Walker equations have been constructed in the context of the entropic formalism, designed for modelling various dynamical aspects of the evolution of the Universe taking into account adiabatic creation of matter. Several forms of exchangeable phenomenological non-extensive entropies associated with the region of the apparent cosmological horizon were used in their derivation. The obtained evolutionary model, consistent with the standard Λ-model for cold dark matter, is intended to describe without introducing new fields the accelerated expansion of the late Universe, providing its cosmological history.