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Topic Review
Thermodynamic Potential
A thermodynamic potential (or more accurately, a thermodynamic potential energy) is a scalar quantity used to represent the thermodynamic state of a system. The concept of thermodynamic potentials was introduced by Pierre Duhem in 1886. Josiah Willard Gibbs in his papers used the term fundamental functions. One main thermodynamic potential that has a physical interpretation is the internal energy U. It is the energy of configuration of a given system of conservative forces (that is why it is called potential) and only has meaning with respect to a defined set of references (or data). Expressions for all other thermodynamic energy potentials are derivable via Legendre transforms from an expression for U. In thermodynamics, external forces, such as gravity, are typically disregarded when formulating expressions for potentials. For example, while all the working fluid in a steam engine may have higher energy due to gravity while sitting on top of Mount Everest than it would at the bottom of the Mariana Trench, the gravitational potential energy term in the formula for the internal energy would usually be ignored because changes in gravitational potential within the engine during operation would be negligible. In a large system under even homogeneous external force, like the earth atmosphere under gravity, the intensive parameters ([math]\displaystyle{ p, T, \rho }[/math]) should be studied locally having even in equilibrium different values in different places far from each other (see thermodynamic models of troposphere].
  • 1.3K
  • 04 Nov 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  
  • 317
  • 15 Apr 2024
Topic Review
Thermodynamic Dissipation Theory of Life
The Thermodynamic Dissipation Theory of the Origin and Evolution of Life argues that the escence of the origin of life was the microscopic dissipative structuring under UVC light of organic pigments (now known as the fundamental molecules of life - those common to all three domains) and their proliferation over the entire Earth surface, driven by the thermodynamic imperative of dissipating this part of the Archean solar spectrum into heat. With time, dissipative structuring led to ever more complex biosynthetic pathways for creating pigments and their support structures (and processes) which could dissipate not only the UVC region but also other UV regions and the visible wavelengths, until today reaching the "red edge" (at approximately 700 nm). The heat of dissipation of photons absorbed on organic pigments in water then catalyzes a host of coupled secondary dissipative processes such as; the water cycle, ocean and wind currents, hurricanes, etc. pushing the limit for dissipation of the incident light even further towards the infrared. The thermodynamic dissipation theory thus assgins an explicit thermodynamic function to life; the dissipative structuring, proliferation, and evolution of molecular pigments and their complexes from common precursor carbon based molecules under the impressed short wavelength solar photon potential to perform the explicit thermodynamic function of dissipating this light into long wavelength infrared light (heat). In a general sense, the origin of life is no different than the origin of other dissipative structuring processes like hurricanes and the water cycle, except that these latter processes deal with structuring involving hydrogen bonding while life deals with structuring involving covalent bonding. The external photon potential supplied continuously by the environment (our Sun), and its dissipation into heat by the assembly of dissipative structures, are, therefore, both integral components necessary for understanding life. Difficult problems related to the origin of life, such as enzyme-less replication of RNA and DNA, homochirality of the fundamental molecules, and the origin of amino acid -codon assignments (information encoding in RNA and DNA), also find simple explanations within this same dissipative thermodynamic framework once the existence of a relation between primordial RNA and DNA replication and UV-C photon dissipation is established.
  • 2.6K
  • 04 Feb 2021
Topic Review
Thermochemical Cycle
Thermochemical cycles combine solely heat sources (thermo) with chemical reactions to split water into its hydrogen and oxygen components. The term cycle is used because aside of water, hydrogen and oxygen, the chemical compounds used in these processes are continuously recycled. If work is partially used as an input, the resulting thermochemical cycle is defined as a hybrid one.
  • 556
  • 14 Oct 2022
Topic Review
Thermo-Mechanical Effects in the Dual Model of Liquids
The Dual Model of Liquids (DML) is a new mesoscopic model of liquids, whose validity and applicability was demonstrated in several cases. It is shown here that DML may even explain crossed effects of Non-Equilibrium Thermodynamics (NET). According to DML, liquids are arranged on a mesoscopic scale by means of aggregates of molecules, or liquid particles. These structures share the liquid world with a population of lattice particles, i.e., elastic waves that interact with the liquid particles by means of an inertial force, allowing the mutual exchange of energy and momentum between the two populations. The hit particle relaxes the acquired energy and momentum due to the interaction, giving them back to the system a step forward and a time-lapse later, alike in a tunnel effect. The transport phenomena in liquids out of equilibrium have been studied since their discoveries, however, no firm theoretical interpretation exists yet. It is demonstrated that the DML may correctly model the thermodiffusion, in particular getting formal expressions for positive and negative Soret coefficient, and another “unexpected” mechano-thermal effect recently discovered in liquids submitted to shear strain, for which the first-ever theoretical interpretation is provided. Both applications of the DML are supported by the comparison with experimental data. The generality of the approach allows us to customize it for other non-equilibrium phenomena of NET.
  • 231
  • 29 Nov 2023
Topic Review
Thermal Diffusivity and Mechanical Properties of Wood
A dependence of Brinell hardness and thermal diffusivity tensor components upon humidity for common pine wood is found. The results of the measurement of Brinell hardness, microhardness, Young’s modulus, and main components of thermal diffusivity tensor for three perpendicular cuts are found to be correlated. It is shown that the mechanical properties correlate better with the ratio of longitude to transversal thermal diffusivity coefficients than with the respective individual absolute values. The mechanical characteristics with the highest correlation with the abovementioned ratio are found to be the ratio of Young’s moduli in longitude and transversal directions. 
  • 719
  • 17 Feb 2022
Topic Review
Thermal Conductivity Measurement
There are a number of possible ways to measure thermal conductivity, each of them suitable for a limited range of materials, depending on the thermal properties and the medium temperature. Three classes of methods exist to measure the thermal conductivity of a sample: steady-state, time-domain, and frequency-domain methods.
  • 1.0K
  • 24 Oct 2022
Topic Review
Thermal Conductivity Improvement of PCCs
To overcome the long-standing disadvantages of PCMs, for instance, small values of thermal conductivity, liquid leakage, separation of phase, and the problem of supercooling, advanced phase change composites (PCCs) manufactured by chemical modifications or the incorporation of functional additives are essential to overcome these disadvantages and promote the large-scale application of PCMs.
  • 610
  • 29 Nov 2022
Topic Review
Theranostic Radiopharmaceuticals
Theranostic Radiopharmaceuticals (Radiotheranostics) is a term in the medical field to define the combination of therapeutic and diagnostic techniques by a suitable radiopharmaceutical agent. Radionuclides are isotopes that emit radiation or have excess nuclear energy, making them chemically unstable and tend to change into another atom. Various types of radiation can be emitted by radionuclides e.g. alpha particles, beta particles, and gamma energy. In radiotheranostics, a pharmaceutical agent (drug) is needed to be a carrier molecule that introduces the radionuclide to its target. Radionuclides are then used as a source of radiation in radiotheranostics that are responsible for diagnosing or treating various diseases.
  • 1.4K
  • 24 May 2022
Topic Review
The TACTIC Telescope
The TACTIC (TeV Atmospheric Cherenkov Telescope with Imaging Camera) is a ground-based gamma-ray telescope in India. The telescope was set up at Mount Abu (24.6∘ N, 72.7∘ E, 1300 m above sea level)  in 1997. The operating principle of TACTIC is based on the imaging atmospheric Cherenkov technique for indirect observation of the gamma-ray sky. Since its first light in 1997, the TACTIC telescope has been employed to explore the Universe at TeV energies and several outstanding results are derived from the TACTIC data.  
  • 827
  • 28 Apr 2021
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