A mathematical model is developed for the fault zone controlled charging of a geothermal reservoir. The model is used to describe a reservoir of finite vertical extent with an impermeable upper boundary. A quasi‐analytic theory is developed for high Rayleigh number convection of liquid in a rigid porous medium. In this approximation, liquid rises up the fault and spreads into the near regions of the reservoir isothermally. The cooling effect of the surface on the fault flow is confined to a thin layer near the surface. This layer grows with distance from the fault. In the far field of the aquifer the full depth of the reservoir is cooled by the surface. A study is made of the effect of various parameters such as mass flow rate, Rayleigh number, and fault width on the pressures, velocities, temperatures, and their gradients at different locations in the fault and in the aquifer. This analysis can be applied to geothermal systems where the thickness of the impermeable reservoir cap is quite small compared to the reservoir depth.

A two‐dimensional conceptual model of the East Mesa Geothermal system is developed on the basis of existing geological, geophysical, geochemical, heat flux, and borehole logging data. Hot water rising in a set of faults is assumed to charge the reservoir, which is overlaid by a clay‐rich cap. The temperature‐depth distribution observed at the site implies that the liquid is converting at a high Rayleigh number. In this approximation, liquid rises up the fault and spreads isothermally into the nearby sections of the reservoir. The cooling effect of the surface on the flow in the reservoir is confined to a thin layer adjacent to the cap‐reservoir interface near the fault. This layer grows with the distance from the fault. Eventually, the entire depth of the reservoir is cooled by the surface. The mathematical model is based on the flow of liquid water in a saturated porous medium. Results are obtained for the velocities, pressures, and temperatures in the entire system consisting of fault zone, aquifer, and clay cap. Finally we compare the predicted surface heat flux to that measured at the site in shallow wells. It is concluded that the model represents a plausible description of fault zone controlled systems like that at East Mesa.

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The SARS-CoV-2 infection spread rapidly throughout the world and appears to involve in both humoral and cell-mediated immunity. SARS-CoV-2 is attached to host cells via binding to the viral spike (S) proteins and its cellular receptors angiotensin-converting enzyme 2 (ACE2). Consequently, the S protein is primed with serine proteases TMPRSS2 and TMPRSS4, which facilitate the fusion of viral and cellular membranes result in the entry of viral RNA into the host cell. Vaccines are urgently required to combat the coronavirus disease 2019 (COVID-19) outbreak and aid in the recovery to pre-pandemic levels of normality. The long-term protective immunity is provided by the vaccine antigen (or pathogen)-specific immune effectors and the activation of immune memory cells that can be efficiently and rapidly reactivated upon pathogen exposure. Research efforts aimed towards the design and development of vaccines for SARS-CoV-2 are increasing. Numerous coronavirus disease 2019 (COVID-19) vaccines have passed late-stage clinical investigations with promising outcomes. This review focuses on the present state and future prospects of COVID-19 vaccines research and development, with a particular emphasis on immunological mechanisms of various COVID-19vaccines such as adenoviral vector-based vaccines, mRNA vaccines, and DNA vaccines that elicits immunological responses against SARS-CoV-2 infections in humans.

Single-phase and two-phase geothermal reservoirs are currently being exploited for power production in Italy, Mexico, New Zealand, the U.S. and Observations show that subsidence due to geothermal fluid production is characterized by such features as an offset of the subsidence bowl from the main area of production, time-lag between production and subsidence and nonlinear stress-strain relationships. Several plausible conceptual models, of varying degrees of sophistication, have been proposed to explain the observed features. At present, relatively more is known about the physical mechanisms that govern subsidence than the relevant thermal mechanisms. Although attempts have been made to simulate observed geothermal subsidence, the modeling efforts have been seriously limited by a lack of relevant field data needed to sufficiently characterize the complex field system.