International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

In constructing the modern sea bottom mines usually seek a compromise between tactical requirements for this type of weapon and requirements for high resistance against possible mine countermeasure-action e.g. make it a cylindrical shape when you need to put an item on the torpedo apparatus submarines, their shell is constructed in the so-called “stealth” technology and is made of non-metallic materials, increasing the quantity of the explosive when the depth of the region is greater, etc. The article proposes an approach that provides a common solution to all these requirements and allows the construction of a highly functional, versatile, high anti-mining resistance sea bottom mine that has no analogue in the naval practice.

The study of the acoustic properties of a pipeline section was conducted in accordance with standards regulating acoustic emission testing of pressure vessels and related activities. To achieve this objective, an experiment was performed to emit acoustic signals on the surface of the pipeline section. Based on the test results and assessment, corrective measures were prescribed to restore the pipeline to optimal operational condition. A multi-channel acoustic system was utilized to carry out the tests on the pipeline section.

A review and analysis of methods for the detection and recognition of unmanned aerial vehicles (UAVs) has been carried out. UAV detection channels were considered – acoustic, optical, radar, infrared, radio reconnaissance channel. The advantages and disadvantages of the channels used are compared and evaluated. In the case of small UAVs, there are a number of significant difficulties and limitations. One of the directions in UAV detection is acoustic observations. The noise created by the UAV’s power plant and propeller is an important unmasking feature. The creation and improvement of methods for the detection, direction-finding and recognition of small UAVs by receiving and processing their sound signals is an urgent task. In the implementation of this method of detection of UAVs are used frequency spectra, spectrograms, normalized autocorrelation functions and phase portraits of acoustic signals. Information features of the UAV sound image can be estimates of spectral coefficients determined from a discrete implementation containing a given number of samples, as well as parameters of autoregressive models.

The report presents and analyses data from tests of steel elements with different cross sections (massivity factor) protected with three different coating thicknesses. The obtained results are presented in graphics. Comparisons between the different protections in terms of fire resistance are made. The tests are part of a large-scale study of the behaviour of the same steel sections with applied reactive protection – intumescent paint (this report) and passive protection – plasterboard and rock wool.

Modern underwater means of protection against terrorist acts are now smart devices. The best option for these devices is that they can be controlled remotely. The present work concerns underwater remote control of explosive devices. Specific applications of the remote device developed by the team are also.

This paper explores the pivotal role of technology and innovation in enhancing the resilience of Bulgaria’s critical infrastructure. It examines the integration of advanced technologies such as artificial intelligence, Internet of Things (IoT), blockchain, digital twins, unmanned aerial vehicles (UAVs), cyber-physical systems (CPS), and big data analytics in sectors like hazardous waste management, border security, and airport security. By analyzing case studies and current implementations, the paper highlights the successes and challenges faced in adopting these technologies. The study also discusses the importance of public-private partnerships and regulatory frameworks in fostering an environment conducive to technological innovation. The findings underscore the necessity for continuous investment in technology to safeguard critical infrastructure against emerging threats and to ensure long-term sustainability.

Vortex Gas Pistons technology has been developed and manufactured to be specifically applied in most air rifles and it uses regular air instead of any other type of gas. Manufacturer ****** offers 6 different types of Vortex Gas Pistons covering most of the Break Barrel and Underlever lines. Despite the demand for high quality materials and optimal construction, operational impacts invariably take their toll on the weapon and defects often occur due to a variety of reasons – either quality or manufacturing defects in the material and those resulting from friction between individual parts, pressure and errors in the maintenance and operation of the weapon.
Each one of the listed impacts, as well as their combination, may be the cause of defects, which in this study are searched for on the items
submitted for evaluation details of original and destroyed air gun piston and barrel, showing defect.

Visual points of interest have various application in different fields of engineering and applied sciences. In example they are used to estimate position and orientation of the scanning device, whether it is a camera, LIDAR or sonar, which is crucial in environment, lacking inertial navigation system. Also are heavily used in Simultaneous Localization And Mapping (SLAM), as well in scene reconstruction and other applications in robotics. The current paper explore the performance of different image descriptors in underwater environment. The lack of navigation system in such environment requires use of said descriptors to estimate the position and orientation of the camera in respect to not moving object.

In their way of operation, electric motors are in themselves electromechanical systems, which to the greatest extent allow realizing the concept of building a mechatronic system. This paper presents a microprocessor-based bench for measuring the current and angular velocity of a brushed DC motor as a function of armature voltage at no-load. The report shows the use of the bench to calculate the parameters of the DC motor and to evaluate its condition. An analysis is made of the condition of the engine and the modes in which it is most efficient.

The report examines and analyzes the experience and requirements for cleaning and contamination of clothing for firefighters. A study was conducted to determine the amount of contaminants found on clothes after their use in fire fighting and cleaning. An analysis of the results was carried out

Floods are the most common natural disasters on the territory of Bulgaria. As a temporary flooding of a significant part of the land as a result of the action of natural forces, destruction of hydro technical facilities (dam walls, dams) or other critical situations (accidents), these are events with a great possibility of prevention and mitigation of negative effects, since unlike other natural disasters, they are highly predictable. In many cases, the timing, nature and expected sizes can be determined in advance, which, together with the preparation of the population for response and crisis management measures, are part of the complex activity of Flood Protection. The researched information system for water management is part of the measures for the effective management of the risk of floods in the territory of the Municipality of Burgas, as the most frequently occurring disaster in the territory of the Municipality, related to large material damages, destruction and casualties. Photos of the operation of the system in real conditions of rising waters of the monitored water bodies are presented, as well as the actions aimed at controlling the negative effects of the disaster.

During out work in a project related to European security, we have created various devices. One of them is a sensor for control of contaminations in the composition of fogs, which is first of its kind in the world. The development of such a sensor is important because in this project, artificially generated fogs with special additives are used for decontamination, and it is crucial to control the quantity of impurities in these fogs. In this work, different aspects of the operation of this sensor, its advantages and design considerations are discussed.