Charged black holes in the infinite derivative theory of gravity

The infinite derivative theory of gravity is a generalization of Einstein gravity with many interesting properties, but the black hole solutions in this theory are still not fully understood. In the paper, we concentrate on studying the charged black holes in such a theory. Adding the electromagnetic field part to the effective action, we show how the black hole solutions around the Reissner-Nordstr{\"o}m metric can be solved perturbatively and iteratively. We further calculate the corresponding temperature, entropy and electrostatic potential of the black holes and verify the first law of thermodynamics.

A Simulation of Four Stroke Marine Diesel Engines to Predict Internal Cylinder Characteristics

This paper introduces a simulation of four-stroke marine diesel engines. The submodel of a particular cylinder was carried out, based on the first law of thermodynamics, programmed by Matlab/Simulink program, which describes the relations among internal characteristics, including cylinder performance parameters, heat release, heat loss, and pressure. The heat release is based on the Wiebe function and the heat loss is based on the Woschni function to build submodels. From the result of the model, the indicated pressure of a single cylinder was taken, the brake power of the engine could be estimated through this pressure. The object of the simulation is a new engine, hence the technical documents and test records provided by the manufacturer are sufficient. The model got the input parameters from this and the key outputs of the model (for example the brake power, peak combustion pressure, specific fuel consumption) were compared with the test records to adjust and make it more accurate. These gaps were not over 5%, therefore, this model can be used to predict key complicated internal cylinder characteristics, for example, the pressure, temperature, and thermal efficiency of engines.

Charge conservation, entropy current and gravitation

We propose a new class of vector fields to construct a conserved charge in a general field theory whose energy–momentum tensor is covariantly conserved. We show that there always exists such a vector field in a given field theory even without global symmetry. We also argue that the conserved current constructed from the (asymptotically) timelike vector field can be identified with the entropy current of the system. As a piece of evidence we show that the conserved charge defined therefrom satisfies the first law of thermodynamics for an isotropic system with a suitable definition of temperature. We apply our formulation to several gravitational systems such as the expanding universe, Schwarzschild and Banãdos, Teitelboim and Zanelli (BTZ) black holes, and gravitational plane waves. We confirm the conservation of the proposed entropy density under any homogeneous and isotropic expansion of the universe, the precise reproduction of the Bekenstein–Hawking entropy incorporating the first law of thermodynamics, and the existence of gravitational plane wave carrying no charge, respectively. We also comment on the energy conservation during gravitational collapse in simple models.

Reducing the Risk of Fire Fighting in Harsh Climatic Conditions

The sustainability of the development of the northern territories of Russia from the Urals to the Pacific Ocean, where the bulk of the country natural resources is concentrated in the twenty-first century, is determined by the integrated approach to planning and managing the risks of using machines, structures and equipment, critical and hazardous industrial facilities and technological support and support at the stages of their operation. Climatic factors have a noticeable effect on increasing the risks of abnormal situations occurrence in emergency situations, for example, on the efficiency of fire departments activity in the winter period of the year and at extinguishing fires in harsh climatic conditions, when water may freeze inside the hoses and in the working chamber of the feed pump. Due to a malfunction in the fire equipment, the scale of the territory covered by the flames can significantly increase, and the extinguishing process will become more complicated. Operability of the hose lines in low temperature conditions is calculated using Methodological Recommendations for ensuring the operability of pump and hose systems of fire trucks when extinguishing fires in the conditions of extremely low temperatures, determining the maximum length of the hose line before icing begins. It is shown in the paper that the maximum length of the hose line, that is, the distance from the pump to the beginning of icing, should be calculated using the heat balance equation, which is based on two equations of the first law of thermodynamics — for flow and heat transfer. At the same time, it is required to combine thermal and hydraulic calculations. The methods are presented in the article for predicting the operability of pumps and hose lines in the conditions of extremely low ambient temperatures, used in fire truck systems for extinguishing fires, including at the energy facilities. It is shown that there are errors and shortcomings in the Methodological Recommendations for ensuring the operability of pump and hose systems of the fire trucks when extinguishing fires in the conditions of extremely low ambient temperatures, including at the energy facilities. It is also shown that the maximum length of the hole line, that is, the distance from the pump to the beginning of icing, should be calculated using the heat balance equation, which is based on two equations of the first law of thermodynamics — for flow and heat transfer.

Experimental Energy and Exergy Analysis of an Automotive Turbocharger Using a Novel Power-Based Approach

The performance of turbochargers is heavily influenced by heat transfer. Conventional investigations are commonly performed under adiabatic assumptions and are based on the first law of thermodynamics, which is insufficient for perceiving the aerothermodynamic performance of turbochargers. This study aims to experimentally investigate the non-adiabatic performance of an automotive turbocharger turbine through energy and exergy analysis, considering heat transfer impacts. It is achieved based on experimental measurements and by implementing a novel innovative power-based approach to extract the amount of heat transfer. The turbocharger is measured on a hot gas test bench in both diabatic and adiabatic conditions. Consequently, by carrying out energy and exergy balances, the amount of lost available work due to heat transfer and internal irreversibilities within the turbine is quantified. The study allows researchers to achieve a deep understanding of the impacts of heat transfer on the aerothermodynamic performance of turbochargers, considering both the first and second laws of thermodynamics.