The Region of Metlaoui Facing Seismic Hazards: Study and Cartographic Approach (South Atlas of Tunisia)

The region of Metlaoui (South Atlas of Tunisia) is listed as one of the major seismotectonic zones of the national territory. About 10 major seismic events with moderate magnitude have occurred from the beginning of last century. The event of 7/11/1989 (Ms = 4.4) was undoubtedly the most important. It caused very significant material damage estimated at 224,525,000 Tunisian Dinars. This study uses a mapping tool to define areas with relatively high degrees of hazard and vulnerability. It also seeks to understand the active fault of the seismic events recorded in this region.

Elastic Material Damage of Rotational Atherectomy and Orbital Atherectomy: An in Vitro Assessment

PurposeRotational atherectomy (RA) and orbital atherectomy (OA) are effective procedures for severe calcified coronary artery disease. Nonetheless, vessel perforation remains an adverse complication of these procedures. This study aimed to evaluate factors affecting elastic material damage caused by RA and OA.MethodsAn in vitro assessment was conducted in which the damage to the rubber latex, an elastic material, after RA was evaluated under various conditions, including burr rotational speed (100,000–220,000 rotations per minute), approaching curve, burr size (1.25 mm, 1.75 mm, and 2.0 mm), and fluid viscosity (water and low-molecular weight dextran). Similarly, the rubber latex damage after OA was evaluated in the same experimental system under various conditions, including crown rotational speed, approaching curve, and fluid viscosity.ResultsIn RA, the rubber latex was damaged at lower rotational speeds (p = 0.003), tighter approaching curves (p < 0.0001), and lower fluid viscosity (p = 0.03). In OA, the rubber latex was generally severely damaged.ConclusionA higher rotational speed, coaxial approach for the wall, and higher viscosity contributed to lesser elastic material damage in RA. The safety mechanism for elastic material in OA proved less effective.

Problems in the investigation of fires of motor vehicles

The article pays great attention to the causes of fires that occur in motor vehicles. Statistical data indicate that fires that occurred in motor vehicles consistently occupy the second place in terms of quantity and material damage after fires that occurred in residential buildings. The investigation of fires related to the ignition of motor transport itself is quite complex. The article analyzes the causes of fires in motor vehicles. Some manufacturing defects of modern cars have been investigated. The statistics of fires in Russia are analyzed and presented. Certain features and directions of investigations of this category of criminal cases are considered.

Monitoring and assessment of fire consequences in the Republic of Buryatia

The article aims to study statistical data on the consequences of fires in the Republic of Buryatia from 2009 to 2020 using the methods of social and mathematical statistics. The study is relevant due to the current situation with fires and integral fire risk indicators in the municipalities. Man-made fires have been a source of increased danger to health and lives of the population, causing great material damage. Fires are a direct threat to the demographic situation in the region since they cause premature mortality. For households, fires undermine social status, destroy social units, cause moral harm aggravating stress, which provokes illnesses. From the technical point of view, man-made fires create risks for dilapidated houses and facilities that do not meet the fire safety requirements. The Republic of Buryatia is a region with a weak degree of industrial development and a vast territory with a low distribution of settlements, i.e. considerable remoteness from the regional centers. The impact of fires (which make up 99% of all types of emergency situation) on the social well-being of the population is studied. Based on the methodology and calculations of fire risks by the number of fires, injured and killed, material damage and destroyed buildings, it was established that the level of protection of residents of Buryatia from fire risks is insufficient. The indicators should encourage the government to develop and implement effective safety measures.

Research on possibilities for monitoring stability of adjacent slopes to transport routes

Development of human society also implies modernization, respectively extension a road and railway transport structures. From this perspective, in order to achieve performance in the field of traffic safety, actions are also required to monitor the slopes, tailings dumps (active or greened) adjacent to transport routes where there are uncertainties regarding their stability. Ignoring stability and landslides can lead to loss of life, as well as significant material damage. Thus, the paper mainly addresses the issue of monitoring the slopes adjacent to road and rail transport routes where there are uncertainties regarding the control of landslides, as well as possibility of alerting before this occurs. From the multitude of possible solutions to be applied in the field, an equipment was developed and realized, which was experienced in real working conditions, and the results confirm validity of assumptions and certify the operation.

Method for Mitigating Stray Current Corrosion in Buried Pipelines Using Calcareous Deposits

Stray current corrosion in buried pipelines can cause serious material damage in a short period of time. However, the available methods for mitigating stray current corrosion are still insufficient. In this study, as a countermeasure against stray current corrosion, calcareous depositions were applied to reduce the total amount of current flowing into pipelines and to prevent corrosion. This study examined the reduction of stray current corrosion via the formation of calcareous deposit layers, composed of Ca, Mg, and mixed Ca and Mg, at the current inflow area. To verify the deposited layers, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) were performed. The electrochemical tests revealed that all three types of calcareous deposits were able to effectively act as current barriers, and that they decreased the inflow current at the cathodic site. Among the deposits, the CaCO3 layer mitigated the stray current most effectively, as it was not affected by Mg(OH)2, which interferes with the growth of CaCO3. The calcium-based layer was very thick and dense, and it effectively blocked the inflowing stray current, compared with the other layers.

The expert system for assessing fire risks of electrical installations in the agrarian industrial complex based on neural networks

The article is devoted to the analysis of fire risks of the operation of electrical installations in the agro-industrial complex of the region. According to statistics, the number of fires occurring for electrical reasons is steadily increasing, which makes the issue of fire risk management relevant. In order to identify and prevent these risks, a technogenic safety system has been developed, presented as a set of methods and tools, which are based on the generation of new data on the causes of threats to the operation of electrical installations based on the analysis of data on the current state of the system. Highlighted characteristics such as Human Parameters, Electrical Installation Parameters and Environmental Parameters. Mathematical models of the given components are considered, a fire risk assessment tree is compiled, in which the input parameters and intermediate vertices with the solution methods in them were determined. The developed model can be used to carry out experiments in order to study the behavior of an electrical installation under various conditions. The application of this method is especially important in cases where the removal of indicators and testing of the operation of an electrical installation is impossible due to the risk of injury or material damage.

Research on Multi-Stage Composite Loading Process Control Method for Roller Staking of Self-Lubricating Spherical Plain Bearings

The staking quality of Self-lubricating Spherical Plain Bearings (SSPBs) directly affects the safety of aircraft and the service life of bearings. Reliable loading process control methods and precise process parameter indexes will come into the creation of efficacious staking quality. Therefore, this paper aims to analyze the mechanical state of the roller staking process and give a load control method and corresponding parameter indexes for the high-quality roller staking process. First, based on the analysis of quality inspection requirements, five states of the deformation degree of the flanging lip of the V groove during the roller staking process were proposed, and their relationship with the requirements was studied. Then, the mechanical states corresponding to the five deformation states of the flanging lip deformation were obtained by numerical simulation, and the feeding displacement was determined. Meanwhile, a Multi-Stage Composite Loading (MSCL) process control method was first proposed to control the material damage of the flanging lip, i.e., the rotate speed of the roller tool was constant during the roller staking process, and the displacement–time control was adopted first; when the staking load reaches a staking value, the force–time control was used to make the staking quality meet the requirements. Finally, the staking quality of the MSCL method was verified though the test. The research shows that the feeding displacement needs to be added to the requirements, and the recommended value is 0.5–0.6 times of the V groove depth. A good surface quality and non-material-damage of the flanging lip is more likely to be obtained by the MSCL process control method. The research reveals the formation mechanism of process deformation, and gives more precise process control indexes. At the same time, it provides a theoretical reference for more reliable technical standards.