This research considers the impact of a point/line heat source/sink on steady magnetohydrodynamic (MHD) natural convection flows in a vertical channel subjected to a transverse magnetic field with a thermal boundary condition of the third-kind thermal (Robin) boundary conditions. A constant point/line heat source/sink generates convection current within the flow. The governing dimensional equations regulating the physical situation at hand are presented in dimensionless form with the associated boundary conditions. Exact solutions are derived for the momentum and energy equations using the Laplace transform technique. The effects of key controlling parameters involved in flow formations are studied, such as the magnetic parameter, point/line heat source/sink parameter and Biot number on flow behaviour are analyzed. MATLAB software is employed to obtain line graphical and tabular results. The findings indicate that lower values of the Biot number account for reduced heat transfer to the surroundings, whilst higher values lead to higher surface heat transfer. Furthermore, the heat transfer rate, frictional drag force and mass flow rate retard as the line heat source/sink approaches a point heat source. In addition, the mass flow rate increases by almost 49% as the interval between the line heat source increases. for both equal and unequal values of the Biot number. There is remarkable agreement between the current results and the previously published studies.

This paper considers the problem of achieving plausible and effective (leading to the formation of structures similar to biological ones) conditions for modeling thermally induced prebiotic processes from the perspective of thermodynamics, thermal physics, and thermal engineering. The article’s presentation is based on the principle of transition from thermal physics and thermodynamics to thermal engineering for constructing planetary environment simulators with controlled environmental conditions. Based on the physical premises from the first parts of this comprehensive review, a conclusion is made regarding the need to consider an additional set of controlled physical parameters or additional factors influencing the models of prebiotic synthesis and formation of precellular/protocell structures implemented in planetary environment simulators and hydrothermal synthesis reactors. Non-thermal heating sources are also considered, such as radiofrequency and microwave irradiation for dielectric heating, as well as radioisotope heating in the early Earth/protoplanet conditions. The coexistence of physical and chemical pathways for heating the prebiotic environment and the feasibility of modeling this separation in planetary environment simulators and controllable climate chamber facilities are highlighted. Exothermic reactions during hydrothermal serpentinization are considered as an example of chemical heating in prebiotic environments. This can lead to the abiotic synthesis of organic matter (which correlates well with the existing hypotheses of the origin of life in alkaline hydrothermal vents, with the mineral genesis of protocells and membrane potential generation on inorganic catalytic protomembranes). Thermal proteinoids and thermal proteinoid microspheres that form on their basis are considered an example of purely organic prebiotic structures obtained via hydrothermal heating. It is demonstrated that the application of thermophysical and thermal engineering approaches to modeling prebiotic systems enables the simulation of many key cellular functions by varying the precursor medium composition and the conditions in thermal experimental setups. Protobiocatalysis and protometabolism, surface (or membrane) potential oscillations, excitability, and physical heredity (thermal fission) are observed in such structures. After addition of the genetic components, the machinery for transcription and translation of the expressed genetic code can also operate within them. The possibility of implementing such models as “hypercycle in protocells” and other proto-metabolic and protogenetic networks capable of oscillation is indicated in prebiotic system models obtained in thermally cycling experimental setups. Kompanichenko’s thermodynamic theory, which also applies to hydrothermal and volcanic conditions that can be simulated in planetary environment simulators, is considered a theoretical justification for the possibility of assembling prebiological systems under such oscillatory conditions. Thus, it becomes possible to move from formal thermodynamics for describing the origin of life to engineering thermodynamics and thermal physics, which allows for the development of experimental setups and simulation chambers for validating various models of prebiological synthesis and the formation of protobiological structures, based on thermodynamic and thermochemical criteria.