Search Results (1,688)

The local energy balance at the liquid-solid front has been widely used in the literature. However, depending on the initial state of the system, the boundary conditions, and the thermodynamic properties of the phase change material, the local energy balance can lead to inaccuracies. The total energy balance has been applied to phase change processes; however, discrepancies have been reported regarding the dynamics of the melting front obtained through this approach. In this work, the concept of thermodynamic equilibrium is used to determine the exact liquid-solid coexistence state in adiabatic systems. Thermodynamic equilibrium of saturated mixtures is used to validate the proposed energy balance. We found that the melting front position obtained from a local energy balance can be underestimated by as much as $37.4\%$ when compared with the equilibrium value. In contrast, the interface position estimated by the total energy balance was in good agreement with equilibrium, with relative differences between $0.082\%$ and $0.11\%$. Finally, a melting experiment using paraffin RT50 was conducted in a thermally insulated cylindrical unit. The experimental front position was underestimated by the local energy balance, with differences between $2.4\%$ and $6.9\%$, while the total energy balance showed smaller discrepancies between $0.28\%$ and $5.71\%$. Full article

Compost amendments are widely recognized as an effective strategy for improving soil quality, modulating enzyme activities, and enhancing nitrogen cycling. Urease, a key enzyme in nitrogen transformation, is characterized by kinetic parameters such as the maximum reaction rate (V_max) and Michaelis constant (K_m), as well as thermodynamic attributes including temperature sensitivity (Q₁₀), activation energy (E_a), enthalpy change (ΔH), Gibbs free energy change (ΔG), and entropy change (ΔS). However, how different compost sources regulate urease kinetics, thermodynamics, and nitrogen availability remains poorly understood. In this study, we evaluated the effects of three compost amendments—mushroom residue (MR), mushroom residue–straw mixture (MSM), and leaf litter (LL)—on urease kinetics and thermodynamics in a temperate agroecosystem. The MSM treatment significantly enhanced urea hydrolysis capacity and catalytic efficiency. In contrast, LL treatment resulted in the highest Km value, indicating a substantially lower enzyme-substrate affinity. Furthermore, MSM reduced the E_a and increased the thermal stability of urease, thereby supporting enzymatic performance under fluctuating temperatures. Collectively, our findings highlight that compost composition is a critical determinant of urease function and nitrogen turnover. By elucidating the coupled kinetic and thermodynamic responses of urease to compost inputs, this study provides mechanistic insights to guide optimized soil management and sustainable nitrogen utilization in temperate agricultural systems. Full article

Materials that allow the storage of a significant amount of heat in a narrow temperature range by a solid–liquid or a solid–solid phase change are called Phase Change Materials (PCMs). Understanding the thermodynamics of PCMs is crucial in PCM R&D for identifying candidate materials, developing new PCMs, and optimizing known PCMs. In this work, a review of the use of entropy to understand the thermodynamics of pure substances as PCMs is performed. Among pure substances, water, alkanes, alkanols, and fatty acids are well-known. Because they give valuable information, elements are also included. While phase change enthalpy and temperature are easy to comprehend and are directly used for application, the opposite holds for entropy. Thus, entropy usually receives little attention. However, as this review shows, entropy is of central importance, and even if it is not analyzed explicitly, then it is implicitly included in the data. If explicitly used, it can reveal crucial information. This is shown by a review of analysis tools and their results from analyzing typical PCMs. The review shows that if entropy is used systematically, a significant improvement in the understanding of the thermodynamics of PCMs is possible. Full article

Climate change is reshaping weather patterns and atmospheric circulation globally, particularly in monsoon-dominated tropical environments. To examine how these changes are unfolding in Bangladesh, we extend the Spatial Synoptic Classification (SSC) using ERA5 reanalysis (1960–2024) at three representative stations (Chittagong, Khulna, and Sylhet) to assess long-term changes in the SSC weather types and their internal meteorological properties. The SSC calendars were constructed and analyzed for seasonal distribution, interannual trends, and decadal anomalies of temperature and dew point. Results reveal that Bangladesh’s climatology is dominated by Moist Tropical (MT), Moist Moderate (MM), and Dry Moderate (DM) weather types with a coherent seasonal cycle. Interannually, MT increased strongly across all stations, while MM and DM declined significantly. Decadal anomalies show consistent warming and moistening since the 2000s, which are most pronounced for Dry Tropical (DT) and MT. These findings indicate that climate change in Bangladesh is expressed not only through shifting frequencies but also through evolving thermodynamic characteristics of daily weather types, underscoring the SSC framework’s value in tropical monsoon regions for generating actionable climate information to support heat-stress planning and climate-health services. Full article

Surface energy is involved in various thermodynamic processes, providing a driving force for thermodynamic reactions. However, surface energies applied in current engineering calculations are generally measured in J/m², which is unsuitable for thermodynamic analysis. To solve this problem, the calculation formula for surface energies was modified to convert the unit of measurement, transforming the non-thermodynamic measurement unit J/m² into the thermodynamically characterized kJ/mol. The calculated surface energy values measured in kJ/mol are unstable due to the influence of the number of atomic layers (t) in the constructed models. Meanwhile, the problem of determining the surface layer thickness, i.e., the number of atomic layers with surface characteristics (t₀), remains unresolved in surface science. Therefore, the extended Finnis Sinclair (EFS) potential was improved by extending the nearest neighbor range and utilized in analyzing the energy per atom, resulting in the determined number of t₀. These results suggest that selecting the surface layer number corresponding to the first to third nearest-neighbor atoms could be appropriate, and the resulting surface energies in kJ/mol appear reasonable. The validity of this computational method and the origin of nanoporous W activity were confirmed by analyzing the changes in total surface energy before and after nano-treatment using the novel nanosized approach. Full article

To investigate the variations in the thermodynamic behavior of large-volume liquid hydrogen tanks under different influencing factors, a numerical model for liquid hydrogen tanks was developed. The changes in thermodynamic behavior in vehicle-mounted liquid hydrogen bottles under different motion states, different operational pressures, and different insulation thicknesses, and their mutual coupling scenarios were studied. The results show that the movement makes the phase state in the liquid hydrogen bottle more uniform, the pressure drop rate faster, and the temperature lower: the heating rate in the liquid hydrogen bottle at 0.85 MPa operational pressure is lower than that at 0.5 MPa and 1.2 MPa. When the operational pressure is coupled with the motion state, the influence of the motion state on the thermodynamic behavior of the fluid is dominant: the temperature near the wall rises rapidly. The temperature near the tank wall rises rapidly; however, as the thickness of the insulation layer increases, both the heating rate inside the liquid hydrogen tank and the temperature difference within the tank gradually tend to stabilize and become uniform. Full article

Liquefied natural gas plays a crucial role in global energy transitions due to its high efficiency and low emissions, especially in long-distance transportation. However, the thermal management of LNG storage tanks remains a significant challenge due to temperature fluctuations, which impact both efficiency and safety. Traditional methods rely on thermodynamic models or computational fluid dynamics simulations but are computationally expensive and time-consuming. This study proposes a hybrid approach that integrates machine learning techniques with CFD data to predict temperature variations inside LNG storage tanks. Several ML models, including Random Forest, XGBoost, and deep learning-based models like CNN and TCN, were tested. Results indicate that CNN and TCN models offer the best performance in predicting temperature changes, showing superior accuracy and computational efficiency. This approach significantly enhances the real-time prediction capability, offering a promising solution for improving LNG tank thermal management, ensuring both operational safety and efficiency. Full article

To reduce fossil fuel dependency in shipping, adopting alternative fuels and innovative propulsion systems is essential. Solid Oxide Fuel Cells (SOFC), powered by hydrogen carriers, represent a promising solution. This study investigates a multi-fuel SOFC system for ocean-going vessels, capable of operating with ammonia, methanol, or hydrogen, thus enhancing bunkering flexibility. A thermodynamic model is developed to simulate the performance of a 3 kW small-scale system, subsequently scaling up to a 10 MW configuration to meet the power demand of a container ship used as the case study. Results show that methanol is the most efficient fueling option, reaching a system efficiency of 58% while ammonia and hydrogen reach slightly lower values of about 55% and 51%, respectively, due to higher auxiliary power consumption. To assess technical feasibility, two installation scenarios are considered for accommodating multiple fuel tanks. The first scenario seeks the optimal fuel share equivalent to the diesel tank’s chemical energy (17.6 GWh), minimizing mass increase. The second scenario optimizes the fuel share within the available tank volume (1646 m³), again, minimizing mass penalties. In both cases, feasibility results have highlighted that changes are needed in terms of cargo reduction, equal to 20.3%, or, alternatively, in terms of lower autonomy with an increase in refueling stops. These issues can be mitigated by the benefits of increased bunkering flexibility. Full article

Beginning with Mandelbrot’s insight that Fisher information may admit a thermodynamic interpretation, a growing body of work has connected this information-theoretic measure to fluctuation–dissipation relations, thermodynamic geometry, and phase transitions. Yet, these connections have largely remained at the level of formal analogies. In this work, we provide what is, to our knowledge, the first explicit realization of the epistemic-to-physical transition of Fisher information within a finite interacting quantum system. Specifically, we analyze a model of N fermions occupying two degenerate levels and coupled by a spin-flip interaction of strength V, treated in the grand canonical ensemble at inverse temperature $\beta$. We compute the Fisher information $F_N\left(V\right)$ associated with the sensitivity of the thermal state to changes in V, and show that it becomes an observer-independent, experimentally meaningful quantity: it encodes fluctuations, tracks entropy variations, and reveals structural transitions induced by interactions. Our findings thus demonstrate that Fisher information, originally conceived as an inferential and epistemic measure, can operate as a bona fide thermodynamic observable in quantum many-body physics, bridging the gap between information-theoretic foundations and measurable physical law. Full article

Here, the effects of Fe vacancy defects on the bonding properties of γ-Fe (111)/α-Al₂O₃ (0001) interfaces are studied in depth at the atomic and electronic levels using first-principles calculations. The first (V₁), second (V₂), third (V₃), and fourth (V₄) layers of vacancy structures within the Fe substrate, as well as the ideal Fe/Al₂O₃ interface structure, are proposed and contrasted, including their thermodynamic parameters and atomic/electronic properties. The results demonstrate that the presence of vacancies in the first atomic layer of Fe deteriorates the interfacial bonding strength, whereas vacancies situated in the third layer enhance the interfacial bonding strength. The effect of vacancy beyond the third layer becomes negligible. This occurs mainly because vacancy defects at different positions induce the relaxation behavior of atoms, resulting in bond-breaking and bond-forming reactions at the interface. Following that, the formation process of vacancies can cause the transfer and rearrangement of the electrons at the interface. This process leads to significant changes in the charge concentration of the interfaces, where V₃ is the largest and V₁ is the smallest, indicating that the greater the charge concentration, the stronger the bonding strength of the interface. Furthermore, it is discovered that vacancy defects can induce new electronic orbital hybridization between Fe and O at the interface, which is the fundamental reason for changes in the properties of the interface. Interestingly, it is also found that more electronic orbital hybridization will strengthen the bonding performance of the interface. It seems, then, that the existence of vacancy defects not only changes the electronic environment of the Fe/Al₂O₃ interface but also directly affects the bonding properties of the interface. Full article

Density functional theory (DFT) calculations were employed to examine how carbon defects, symbiosis, and sulfur influence the wettability of coal pyrite by analyzing H₂O adsorption on distinct surface configurations. The comparison results of adsorption energy, Mulliken population, charge density, and electronic state density of water molecules on the surface of pyrite doped with carbon atoms show that the presence of carbon doping reduces the negative value of the adsorption energy of water molecules on the pyrite surface, the C atoms on the pyrite surface form weaker C-H bonds with the H atoms in the water molecules, the Fe-O bond strength weakens, and the thermodynamic trend weakens. And the bond of the pyrite surface with adsorbed carbon changes from an Fe-O bond to an Fe-C-O bond. The adsorption of water molecules on the pyrite surface is weakened, and there is a weaker thermodynamic trend. This is because the adsorption of carbon atoms changes from hydrophilic to nearly hydrophobic. The physical adsorption of sulfur atoms changes the adsorption energy of water molecules on the pyrite surface from negative to positive, and the bond changes from an Fe-O bond to an Fe-S-O bond, indicating that the adsorption intensity of water molecules on the pyrite surface with adsorbed sulfur is weakened, and there is no thermodynamic trend. The pyrite surface with adsorbed sulfur changes from hydrophilic to hydrophobic. Under the same impurity atom doping or adsorption concentration, the influence of sulfur on the adsorption of water molecules on the surface of pyrite is the greatest, followed by the adsorbed carbon, and the weakest is the carbon atom doping. Macroscopically, the overall hydrophobicity of the surface of coal-bearing pyrite covered with sulfur is greater than that of pyrite containing adsorbed carbon and even greater than that of coal-bearing pyrite doped with carbon atoms. Full article

In this presentation, we have identified the domain of equivalence amongst the Boltzmann, Gibbs, and thermodynamic entropies. In this domain, ergodicity is followed even for (i) all nonequilibrium steady states and (ii) those time-dependent nonequilibrium states belonging to it. The condition of this domain is either that the rate of entropy change is zero or its magnitude is exceedingly small. Its implication is that, in this domain, Jaynes’ principle of maximum entropy estimate also holds. Outside this domain, the said equivalence among three entropies is not feasible, and the operation of the Jaynes’ principle of maximum entropy estimate does not remain of practical utility. Full article

The Technology-Enhanced Learning (TEL) Marketplace was a joint initiative by the vice rectorate for academic affairs and the vice rectorate for digitization and change management at Graz University of Technology to modernize lectures. As part of this initiative, an exercise course on chemical thermodynamics was redesigned as a learner-centered course and enriched with interactive learning materials designed to promote self-directed learning. The core of the method used to implement this redesign is interactive notebooks created in Wolfram Mathematica to enable students to work through the examples independently, in depth, and irrespective of time, with the required theoretical background integrated into the notebooks. In this paper, we ask the following questions: RQ1: How did students use and accept the interactive notebooks? RQ2: What was the impact of the interactive notebooks and the corresponding course design as perceived by the students? To answer these questions, we conducted a questionnaire-based survey with 45 course students and statistically analyzed the results. Key results for RQ1 show that $93.33\%$ of the participating students reported using the interactive notebooks, and technology acceptance (1 = low TA, 5 = high TA) was high in both the dimensions of perceived usefulness ($m=3.88$) and attitude ($m=4.24$). Regarding RQ2, our key results show that students perceived the notebooks to have a positive impact on their learning experience, especially regarding their self-directed learning. The results of this work are in alignment with observations by lecturers, which showed that this more student-centric course design and the integration of the interactive learning materials made it possible to clarify detailed questions during the independent learning phase, allowing the interactive part of the course to focus on the tactical approaches, solutions, and problems that arose during the calculations, which raised the overall level of content teaching. Full article

The subject of this paper is an analysis of the use of wall heating and cooling modules with heat pipes for efficient space heating and cooling. The modules under consideration constitute a structural element installed in the room’s partition structure and consist of heat pipes embedded in a several-centimeter layer of concrete. Water-based central heating and chilled water systems were used as the heat and cooling source. The heat pipes are filled with a thermodynamic medium that changes state in repeated gas–liquid cycles. The advantage of this solution is the use of heat pipes as a heating and cooling element built into the wall, instead of a traditional water system. This solution offers many operational benefits, such as reduced costs for pumping the heat medium. This paper presents an analysis of the potential of using heat pipe modules for heating and cooling in real-world buildings in Poland. Taking into account the structural characteristics of the rooms under consideration (i.e., internal wall area, window area), an analysis was conducted to determine the potential use of the modules for space heating and cooling. The analysis was based on rooms where, according to the authors, the largest possible use of internal and external wall surfaces is possible, such as hotels and schools. Based on the simulations and calculations, it can be concluded that the modules can be effectively used in Poland as a real heating and cooling element: standalone, covering the entire heating and cooling demand of a room, e.g., a hotel room, or as a component working with an additional system, e.g., air cooling and heating in school buildings. The changes in outdoor air temperature, during the year analyzed in the article, were in the range of −24/+32 °C. Full article

According to the production process requirements of oriented silicon steel in a certain steel mill, optimization of the slag composition ratio is studied through thermodynamic calculations. The CaO-SiO₂-Al₂O₃-FeO-MgO slag system is studied using FactSage thermodynamic software (FactSage 8.1), and a slag optimization plan is proposed based on industrial experiments involving changes in the composition ratio of the slag, calculation and analysis of the melting characteristics of RH refining slag, further verification through orthogonal experiments, and observations of the slag state, temperature, and composition relationship through phase diagrams. This study provides theoretical guidance for finding a suitable slag composition ratio based on the influence of slag on dissolved aluminum in steel liquid. Research has shown that, combined with thermodynamic analysis, slag melting characteristics, component content calculations, and industrial experiments, the range of RH refining slag composition suitable for production in this steel mill is slag in the range of 1.3~1.5 alkalinity, 25~30% Al₂O₃, 5~6% MgO, and 1–2% FeO. Full article