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Topic Review
High Entropy Alloys
High-entropy alloys (HEAs) are alloys that are formed by mixing equal or relatively large proportions of (usually) five or more elements. Prior to the synthesis of these substances, typical metal alloys comprised one or two major components with smaller amounts of other elements. For example, additional elements can be added to iron to improve its properties, thereby creating an iron based alloy, but typically in fairly low proportions, such as the proportions of carbon, manganese, and the like in various steels. Hence, high entropy alloys are a novel class of materials. The term “high-entropy alloys” was coined because the entropy increase of mixing is substantially higher when there is a larger number of elements in the mix, and their proportions are more nearly equal. These alloys are currently the focus of significant attention in materials science and engineering because they have potentially desirable properties. Furthermore, research indicates that some HEAs have considerably better strength-to-weight ratios, with a higher degree of fracture resistance, tensile strength, as well as corrosion and oxidation resistance than conventional alloys. Although HEAs have been studied since the 1980s, research substantially accelerated in the 2010s.
  • 3.0K
  • 01 Dec 2022
Topic Review
Working Fluids
Heat engines, refrigeration cycles and heat pumps usually involve a fluid to and from which heat is transferred while undergoing a thermodynamic cycle. This fluid is called the working fluid. Refrigeration and heat pump technologies often refer to working fluids as refrigerants. Most thermodynamic cycles make use of the latent heat (adventages of phase change) of the working fluid. In case of other cycles the working fluid remains in gaseous phase while undergoing all the processes of the cycle. When it comes to heat engines, working fluid generally undergoes a combustion process as well, for example in internal combustion engines or gas turbines. There are also technologies in heat pump and refrigeration, where working fluid does not change phase, such as reverse Brayton or Stirling cycle. This article summarises the main critera of selecting working fluids for a thermodynamic cycle, such as heat engines including low grade heat recovery using Organic Rankine Cycle (ORC) for geothermal energy, waste heat, thermal solar energy or biomass and heat pumps and refrigeration cycles. The article addresses how working fluids affect technological applications, where the working fluid undergoes a phase transition and does not remain in its original (mainly gaseous) phase during all the processes of the thermodynamic cycle. Finding the optimal working fluid for a given purpose – which is essential to achieve higher energy efficiency in the energy conversion systems – has great impact on the technology, namely it does not just influence operational variables of the cycle but also alters the layout and modifies the design of the equipment. Selection criteria of working fluids generally include thermodynamic and physical properties besides economical and environmental factors, but most often all of these criteria are used together.
  • 2.6K
  • 04 Nov 2022
Topic Review
Drinking Bird
Drinking birds, also known as insatiable birdies, dunking birds, drinky birds, water birds, dipping birds, and “Sippy Chickens” are toy heat engines that mimic the motions of a bird drinking from a water source. They are sometimes incorrectly considered examples of a perpetual motion device.
  • 2.6K
  • 25 Nov 2022
Topic Review
Domestic Refrigerators in Smart Grids
Domestic refrigeration and freezing appliances can be used for electrical load shifting from peak to off-peak demand periods, thus allowing greater penetration of renewable energy sources (RES) and significantly contributing to the reduction of CO2 emissions. The full realization of this potential can be achieved with the synergistic combination of smart grid (SG) technologies and the application of phase-change materials (PCMs). Being permanently online, these ubiquitous appliances are available for the most advanced strategies of demand-side load management (DSLM), including real-time demand response (DR) and direct load control (DLC).
  • 807
  • 27 Oct 2022
Topic Review
Non-equilibrium Thermodynamic Foundations of the Origin of Life
There is little doubt that life’s origin followed from the known physical and chemical laws of Nature. The most general scientific framework incorporating the laws of Nature and applicable to most known processes to good approximation, is that of thermodynamics and its extensions to treat out-of-equilibrium phenomena. The event of the origin of life should therefore also be amenable to such an analysis. The Thermodynamic Dissipation Theory of the Origin and Evolution of Life postulates that the first molecules of life (the fundamental molecules) were, at their origin, pigments dissipatively structured through photochemical and chemical reactions on the surface of the oceans from simpler and more common precursor molecules in water under the solar long-wavelength UVC (205–285 nm) light of the Archean. They were “designed” by Nature to carry out this thermodynamic imperative of absorbing light in this UVC region and then to dissipate it into heat (longer wavelength photons) released into the environment. 
  • 760
  • 13 Apr 2022
Topic Review
Thermodynamic Insights into Symmetry Breaking
Symmetry breaking is a phenomenon that is observed in various contexts, from the early universe to complex organisms, and it is considered a key puzzle in understanding the emergence of life. The importance of this phenomenon is underscored by the prevalence of enantiomeric amino acids and proteins. The presence of enantiomeric amino acids and proteins highlights its critical role. However, the origin of symmetry breaking has yet to be comprehensively explained, particularly from an energetic standpoint.  Therefore, a novel approach is explored by considering energy dissipation, specifically the lost free energy, as a crucial factor in elucidating symmetry breaking. A comprehensive thermodynamic analysis applicable to all scales from elementary particles to aggregate structures such as crystals is performed, we present experimental evidence establishing a direct link between nonequilibrium free energy and energy dissipation during the formation of the structures. Results emphasize the pivotal role of energy dissipation, not only as an outcome but as the trigger for symmetry breaking. This insight suggests that understanding the origins of complex systems, from cells to living beings and the universe itself, requires a lens focused on nonequilibrium processes  
  • 729
  • 15 Apr 2024
Topic Review
Ergontropic Dynamics
Ergontropic dynamics is a concept that links dynamics and thermodynamics based on the concept of energy, work, and entropy. It differs from standard treatments, in particular, in that it does not derive irreversible thermodynamics from reversible microscopic dynamics and the force term, dp/dt, is derived from these principles and not assumed ab initio. The concept offers an intelligible explanation of a number of physical problems by embedding the universal tendency of energy to a minimum and entropy to a maximum in a new framework. The result is a modification of Newton’s dynamic equation of motion that bases the principles of mechanics on the concepts of energy and entropy, rather than the usual definition of force, and integrates the description of translation and vortex motion into a consistent framework. By reframing the fundamental concepts of classical mechanics and electrodynamics through the perspectives of energy and entropy, ergontropic dynamics stands as a novel framework that transcends both of these fields. 
  • 642
  • 30 Aug 2023
Topic Review
Free Entropy
A thermodynamic free entropy is an entropic thermodynamic potential analogous to the free energy. Also known as a Massieu, Planck, or Massieu–Planck potentials (or functions), or (rarely) free information. In statistical mechanics, free entropies frequently appear as the logarithm of a partition function. The Onsager reciprocal relations in particular, are developed in terms of entropic potentials. In mathematics, free entropy means something quite different: it is a generalization of entropy defined in the subject of free probability. A free entropy is generated by a Legendre transformation of the entropy. The different potentials correspond to different constraints to which the system may be subjected.
  • 569
  • 04 Nov 2022
Topic Review
Complex flow and heat transfer characteristics in microchannels
Continuously improving heat transfer efficiency is one of the important goals in the energy field. Compact heat exchangers characterized by microscale flow and heat transfer have successfully provided solutions for this purpose. However, as the characteristic scale of the channels decreases, the flow and heat transfer characteristics may differ from those at the conventional scale. When considering the influence of scale effects and changes in special fluid properties, the flow and heat transfer process becomes more complex. The conclusions of the relevant studies have not been unified, and there are even disagreements in some aspects. Therefore, further research is needed to obtain a sufficient understanding of flow structure and heat transfer mechanisms in microchannels. There are a lot of research about microscale flow and heat transfer, focusing on the flow and heat transfer mechanisms in microchannels, which is elaborated into the following two perspectives: one is the microscale single-phase flow and heat transfer that only considers the influence of scale effects, the other is the special heat transfer phenomena brought about by the coupling of microscale flow with special fluids (fluid with phase change (pseudophase change)). The microscale flow and heat transfer mechanisms under the influence of multiple factors, including scale effects (such as rarefaction, surface roughness, axial heat conduction, and compressibility) and special fluids, are investigated, which can meet the specific needs for the design of various microscale heat exchangers.
  • 500
  • 03 Aug 2023
Topic Review
KinITC
The method kinITC for kinetic Isothermal Titration Calorimetry is an extension of the classical ITC technique in view of obtaining kinetic information in addition to thermodynamic information. It has been described in full in, and in a simplified and less general form in.
  • 489
  • 04 Nov 2022
Topic Review
Energy Budgets in Growing Cities
Energy rate density is a useful metric to track the evolution of energy budgets, which help facilitate how well or badly human society trends toward winning or losing. The fates of nations and their cities are unknown, their success is not assured. Those nations and cities with rising per-capita energy usage while developing and those that are nearly flat while already developed seem destined to endure; those with falling energy usage seem likely to fail.
  • 477
  • 17 Nov 2022
Topic Review
Plate Heat Exchanger for Condensing Duties
Increasing energy usage efficiency requires enhanced heat energy recuperation between process streams in the industry and civic sector with waste heat utilization. The condensation of different vapours is the process encountered in many industrial applications.  Increasing the heat recuperation in this process is possible with efficient heat transfer equipment, among which a Plate Heat Exchanger (PHE) is at the leading position. PHE in processes of vapour condensation is the fast-developing type of heat transfer equipment. Their main advantages compared to traditional shell-and-tube heat exchangers are compactness, small mass and inner volume, and enhanced heat transfer. The construction of PHE can be adapted to the required conditions of specific applications as condensers. 
  • 474
  • 02 Mar 2023
Topic Review
Methods for Improving Thermal Fatigue Resistance of Copper
Thermal fatigue is the fatigue failure phenomenon caused by the thermal stress (or thermal strain) cycle caused by the temperature gradient cycle. 
  • 438
  • 11 May 2023
Topic Review Video
Arsenic Contamination of Groundwater
At a great many locations worldwide, the safety of drinking water is endangered by pollution with arsenic. Arsenic toxicity is a matter of both systems chemistry and systems biology: it is determined by complex and intertwined networks of chemical reactions in the inanimate environment, in microbes in that environment, and in the human body.
  • 416
  • 31 Jan 2024
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