In the present paper, the use of programmable microprocessors to develop a computerized stand for the preparation of a mixture of flammable/toxic/explosive gases in order to obtain mixtures at concentrations in explosive range is presented. The operating principle of the stand is based on the mixing of two volumetric flows, controlled with the help of microprocessors, where gases are stored and circulated at atmospheric pressure through cylindrical injectors, driven by stepper motors so that the gas circuit does not require valves. The exit of the stand is a homogenization chamber, with agitator and sensor to confirm the desired concentration of the mixture. This automated stand eliminates mechanical, electric or pneumatic valves from the gas circuits, avoiding elements with high mechanical resistance suitable for high pressures/depressions, removing the possibility of the return of the gas flow, without sensitivity to sudden pressures variations.

To deal with any such applications, it is a must to understand the basic form and nature of the governing equations of fluid dynamics. It is imperious to fully understand the basic of numerical discretization that can be applied in equations. This paper aims to present some CFD tools that are the starting point in solving problems related to the field of fluid dynamics. During this work, we will note that anyone CFD technique will not be appropriate for all problems and the diverse mathematical nature of partial differential equations will ensure that some algorithms will best work for hyperbolic equations and others will do best for elliptic equations. In addition, this paper examines precisely how CFD techniques can be used to solve various flow problems. In other words, CFD applications requires the simultaneous knowledge of some major aspects, such as the governing flow equations and their mathematical behavior, aspects of numerical discretization of partial differential equations, also known as finite differences or of integral equations, known as finite volumes. Computational fluid dynamics has a major impact on airplane design and soon to be a critical technology for aerodynamic design with the purpose to enhance the design process for any machine that deals with fluid flow.

In the following study, experimental results are obtained from an automated stand. With the help of this experimental stand, visualization techniques such as Schlieren and Shadowgraph can be applied, to study the flame front propagation of air and inflammable gas mixtures initiation. In parallel, an infrared sensor was used to control a push-pull solenoid to open the gas escape diaphragm of the stand. To obtain the explosive gas mixture at various concentrations (between the lower explosion limit and the upper explosion limit) an original programmable mixer was used, based on computational algorithms for accurate control of stepper motors which allow attainment of air and inflammable gas flows in order to achieve a homogeneous and continuous mixture at the desired concentration. The performed experiments allow for a better understanding of the flame front production and propagation, facilitating the knowledge and optimization of the operating times from the reduction mechanisms for reducing the effects of explosions of the flammable gas-air mixtures.

In the following paper, experimental results regarding the effect of explosion pressure are obtained from open field experiments with detonation of explosive charges. In addition, sensors that can be used for security applications for the detection of toxic and explosive compounds, as well as mobile systems for the detection of shock waves due to explosions were used to acquire more detailed results. Sensors are the main components in products and systems used to detect chemicals and volatile organic compounds (VOCs) targeting applications in several fields, such as: industrial production and the automotive industry (detection of polluting gases from cars, medical applications, indoor air quality control. The sensory characteristics of a robot depend very much on its degree of autonomy, the applications for which it was designed and the type of work environment. The sensors can be divided into two categories: internal status sensors (sensors that provide information about the internal status of the mobile robot); external status sensors (sensors that provide information about the environment in which the robot operates). Another classification of these could be: distance sensors, position sensors, environmental sensors - sensors that provide information about various properties and characteristics of the environment (example: temperature, pressure, color, brightness), inertial sensors.

The dangers associated with hydrogen mainly come from its wide flammability range, it’s extremely fast burning rate (having much more aggressive explosive properties than methane gas) and the considerable amount of energy released when it burns or explode. The development of new applications that use hydrogen as clean energy is constantly increasing, thus, hydrogen can be used on a large scale. This paper presents the use of computational fluid dynamics techniques, regarding the linear propagation of the explosion of air and hydrogen mixture in closed spaces, the main purpose being the determination of the overpressures to which a test stand of this processes is subjected.

On 2021, in the intensive care unit of a County Emergency Hospital where oxygen therapy treatment was applied to COVID patients, located in the municipality of Ploiesti, Prahova County, a fire occurred that resulted in the destruction by burning of the ICU room, the death of two people, and the injury of a medical professional. In order to elucidate the accelerating causes of the combustion phenomenon of materials in the ICU room, a combustion stand was designed whose atmosphere can be controlled in terms of achieving high oxygen concentrations of 40% vol., in accordance with the treatment schemes applied to the patients and with the configuration of the room and the frequency of use of the access door. In this experimental stand, a series of combustion tests of flexible polyurethane foam samples were performed, which highlighted the acceleration of combustion and the complete consumption of the mass. The purpose of this work is to explain the rapidity of the fire in a hospital ward, both with experimental methods and with the help of FDS.