RESULTS AND ANALYSIS OF ACHIEVED JOINT RESEARCH AND ACTIVITIES BETWEEN REZEKNE ACADEMY OF TECHNOLOGY AND VASIL LEVSKI NATIONAL MILITARY UNIVERSITY

In 2018, the first group of teachers and students from Vasil Levski National University conducted experiments on laser marking in Rezekne Academy Of Technology, Latvia. Since then, joint research has been increasing every year and better results have been achieved not only in the field of laser technologies, but also in other areas of joint interest. A pilot study group is even being formed in a master's program in laser technology. As a result, the interest in laser technologies and in Latvia at Vasil Levski National University increased significantly. Research has been done on the impact of the exchange between the two institutions on the learners and their motivation to learn

State of Radiation Protection in Bulgaria

In the months of February and March 2017, I conducted a survey among 3 population groups and 392 participants on the state of the systems for monitoring and alerting the population, so the information received is up-to-date. The information received and summarized should not be taken as a constant, since the situation is changing dynamically, both in terms of the political situation in Bulgaria and the region and the intentions of our neighbors in relation to sites that present radiation risks and in terms of meteorological elements that influence possible radioactive contamination. Particularly dynamic is the development of meteorological elements that need to be analyzed very thoroughly in the event of a nuclear accident or incident. The results and consequences of the closure of uranium production and its processing in Bulgaria, as well as the storage of radioactive waste in Bulgaria, are shown. The results of the study are presented, diagrams are presented, and analyses and directions for follow-up are made

IMPACT OF TYPES OF ELECTROMAGNETIC RADIATION ON LIVING NATURE

In our daily life we are exposed to electromagnetic radiation in a very wide range. In our century, these radiations are constantly increasing, and we do not always know how to protect ourselves from them and how they affect people and the rest of living nature. An attempt has been made to analyze the impact of emissions from a different frequency spectrum - from power supply with a frequency of 50 Hertz to high-frequency mobile communications with a frequency of up to 300 GHz. Studies in countries of Europe and the world were taken as a basis, and a study was made about the impact of these electromagnetic radiations in Central Northern Bulgaria and the Veliko Tarnovo region. It is shown how morbidity changes when they affect the peripheral and central nervous systems of people and what effect they can cause at high powers and high intensity at short distances.

INFLUENCE OF METEOROLOGICAL ELEMENTS IN ACCIDENTS IN ENTERPRISES WITH RADIOACTIVE ELEMENTS OR DANGEROUS CHEMICAL SUBSTANCES IN BULGARIA

In the analysis of the meteorological elements that influence the spread of radioactive particles, radioactive isotopes and dangerous chemical substances on the territory of Bulgaria, the winds and air currents that form in the airspace over Bulgaria are considered. These are the main meteorological elements that most strongly influence the change in the radioactive background. Another element that has an impact is precipitation in its various manifestations - horizontal and vertical in appearance and depending on the aggregate state of the water. Due to their negligible influence on the radiation environment, we will exclude the remaining meteorological elements from the factors forming the natural indicators of the state of the atmosphere, water and soil. Their influence in areas where there are located large enterprises working with such substances is presented.The report examines the influence of the main factor - the movement of air masses at different altitudes in the atmosphere in the Ludogorie region and the Danube River as an area where NPPs are located in Bulgaria and Romania and which, in the event of an accident, would cause the greatest consequences. The winds in 3 cities from this region, which are located near these enterprises, are described and the corresponding analysis is made.

FEATURES OF COLOR LASER MARKING ON METALS

In the research carried out at the Rezekne Academy of Technology, the technology for color laser marking on chromium-nickel base and other metal bases was used in industrial production from the point of view of the repeatability and stability of the produced color markings. The study and research was done during the Erasmus internship by the authors at the Academy of Technology in Rezekne, Latvia. For this purpose, an AISI 304 color palette consisting of fifteen colors was developed and implemented. After the practical experiments, the dependence of the obtained colors on the various parameters of the laser processing was analyzed. The resulting colors were then tested using optical, scanning electron and atomic force microscopy, and the configuration of the oxide films was determined by Raman spectroscopy. The resulting colors are of appropriate uniformity, brightness and cover almost all spectral zones, and the resulting colors are of many times better quality than other metallic bases. A color standardization and palette repeatability test was also performed by evaluating the reflectance spectra of the formed colors. The color palette demonstrated high repeatability for all but one particular color. In parallel, the stability of the color markings was studied in terms of environmental, mechanical and chemical resistance. The resulting colors show high resistance to most environmental conditions; however, exposure to very high temperatures and extreme humidity (100 °C, 90%) and to low temperatures and extreme humidity (-40 °C, 90%) results in degradation of several colors. Colored brands show high hardness and excellent mechanical resistance to external influences and exceptional resistance to various chemicals, except for acid solutions and salts.

USE OF CO2 LASER FOR MARKING AND CLEARING OF TEXTILE MATERIALS FOR MANUFACTURE OF MILITARY EQUIPMENT

In the last decades, a large application has been found by lasers in marking and cutting on textiles, plexiglass, wood, metals and other materials. These items apply to both the military and the economy of the countries of the world. A group of Bulgarian students from the National Military University Vasil Levski, led by Dr. Nikolay Dolchinkov, conducted a research with a group of TAR under the leadership of Prof. Lubomir Lazov at the Laser Center in Rezekne at the end of 2018. The report shows the achieved results and the relevant analyzes. Graphically and tabularly, the dependence of the depth of the markings and the cut-off of the power and speed of the used CO2 laser are presented

Protection of biological objects from electromagnetic radiation

The article deals with issues related to the impact of electromagnetic radiation (EMR) on humans and biological objects (bio-objects). Such types of radiation as electromagnetic fields of low frequency and microwave range, infrared and ultraviolet and ionizing radiation are considered. Data on the harmful effects of EMR on biological objects are given. The basic principles of protection against EMR are considered

STUDY OF LASER CUTTING AND MARKING ON THE FILT WITH THE HELP OF A CO2-LASER

Describe the parameters influencing the depth of the laser marking of textile products. Experimental results are presented to determine the quality of cuts on felt surfaces of different colors at specific parameters - power and speed. Approximately 100 extras were made on two materials with a change in laser power and speed. As a result, the optimal results for cutting and marking a felt are shown.

STUDY OF CUTTING AND LABELING OF POLYMETHYLMETHACRYLATE USING A CO2 LASER

Progress in direct laser marking when processing plastics with unmatched quality of markings, contrast and speed. This article presents the latest generation of laser materials and laser equipment systems. When properly applied, laser marking can provide quality for production and add value to the appearance and function of the product.Describe the parameters influencing the depth of the laser marking of polymethylmethacrylate (PMMA) products. Experimental results are presented for determining the quality of cuts on the polymer surface at specific parameters - power and speed

Radiation safety of Bulgaria in the contemporary international situation

It is known that everything on our planet is subjected to constant exposure from the natural and anthropogenic, earth and space SIR, and is situated in conditions created by natural and technical radioactive Backlight. The ionizing radiations accompany planet life in its diff erent manifestations of all phases of the evolution. The National Automated System for continuous monitoring of the radiation background has 26 local monitoring stations (LMS) covering the whole country, with greater density around NPP ‘Kozloduy’. Radiometric measurements in real conditions, sampling, and analysis are carried out by the Executive Environment Agency (EEA) at the MoEW and radiological control laboratories. A special place in radiation safety is taken by timely detection of radioactive waste and materials that appear in one way or another in the environment