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.

APPROACH TO THE FORMING OF RATIONAL TECHNOLOGY FOR THE EXPORT CARGOES DELIVERY IN SUPPLY CHAIN ON THE PRINCIPLES OF CO-MODALITY

In this article, we propose an approach to the forming of rational technology for the export cargoes delivery in the supply chain on the principles of co-modality in the context of effective interaction of delivery participants, which allows reducing the costs of all them through the optimal use of resources related to delivery and increasing the competitive advantages of products. Taking into account the strengthening of cooperation between road and rail transport, under modern conditions, combined transport within the international transport corridor is proposed as an alternative option to promote cargo flow in the supply chain. As a result of experimental studies carried out on the basis of the simulation model of the delivery process in the Petri Nets, the time characteristics of technological processes under alternative schemes depending on the input parameters of the model have been determined. A comparative assessment of alternative delivery schemes based on mathematical models has made it possible to establish that the rational scheme for the delivery of export cargo from Ukraine to Germany via the Pan-European Corridor III is the Rolling Highway technology, which ensures compliance with the cargo owner\u27s requirements for delivery time and cost established by the contract. The proposed approach is recommended as a tool for making managerial decisions when planning and organising the delivery of export cargoes from Ukraine to the EU countries in order to effectively manage supply chains by minimising the cost of delivery and environmental damage.

COMPARATIVE ANALYSIS OF METHODS FOR MEASURING LASER POWER

The application of lasers in many fields of technology and medicine is constantly increasing. This causes the development of new physical methods and principles for correct measurement of power, energy, and other parameters of laser sources. In most cases, the correct measurement of the laser power is important because the quality of the processes in which laser sources are used depends on it. In the paper, a comparative analysis of the existing methods for measuring the power and energy of laser radiation of diverse types of laser sources is made. This research aims to help users of laser equipment to choose the right measurement method depending on the laser source

EXPERIMENTAL STUDIES OF AN ALGORITHM FOR MINIMIZING THE IDLE TOOL MOVES WHEN MILLING COMPLEX SURFACES ON TRIAXIAL CNC MACHINE TOOLS

The idle running times of the working units of a machine tool are the sum of the idle running times for the tool change and for changing the section uder treatment. The time, spent on idle running is the extra machining time. A large number of milling cutters are used for purely mechanical machining of details with complex surfaces and for a significant number of machined sections, where the complex surface is broken as a rule. This leads to an increase in the extra time for treatment. Reducing the auxiliary time in machining the parts will significantly increase the productivity of the actual milling process. When modeling the process of machining details with complex surfaces on triaxial milling machines, the optimization of the sequence of moves will allow to reduce the idle running time by up to 50% without causing deterioration in the quality of the surface layer. In modern production a method is needed, which would allow to automatically and quickly enough make a choice of an optimal option for a sequence of performing tool moves while taking into account the durability of the metal cutting tool

STUDY OF TECHNOLOGICAL CHAINS FOR RAPID PROTOTYPING OF ORTHODONTIC DENTAL PRODUCTS

The paper presents results from studying the possibilities of digital layering technologies (DLP SLA - Digital Light Projector Stereolithography) for construction of biomedical orthodontics devices (aligners). Experimental data on the mechanical and aesthetical properties (transparency) of the materials used has been studied in comparison with the conventional technologies for producing the aligners - Vacuum Forming (VF). The paper discuss the influence of the design of the devices (e.g. thickness) and technological parameters (e.g. stirring time) of the processes on the mechanical properties and orthodontics functionality of the materials as well as the quality and accuracy of the devices (models and functional prototypes for dental applications).

SELF-ASSESSMENT OF PROSPECTIVE ENGINEERS’ CAREER MANAGEMENT IN THE CONTEXT OF QUANTUM TRANSITION THEORY IN SOCIAL SCIENCES

We live in a changing and complex world open for potential personal development. At the same time, the Earth is moving to a new level, from a 3-dimensional to a 5-dimensional level. This process is called the quantum transition.  Nowadays career management theories are developing and changing under the influence of the quantum transition paradigm, thus the perception of career and the understanding of career have also changed. A career covers the whole life of a person and is individually driven. So, we can speak of a self-directed personal career, which is connected with finding one’s mission in life, one’s vocation. So, moving into the fourth and fifth dimensions opens up more possibilities for finding your purpose: 1) motivated individual choice; 2) career management based on that choice; 3) transition from survival to mission; 4) access to the information field of the Universe; 5) discovery of new abilities – telekinesis, teleportation, clairvoyance, clairaudience, etc. The article considers the notion of the quantum transition, career, career management and the characteristics of the Generation Z from the perspective of various authors. The analysis is carried out by assessing the data acquired on the specific features of the existent career management and the possibilities which provides the current situation for the engineers-to-be. The research aim is to study the specific features of the career management of the prospective engineers in the perspective of the quantum transition. The obtained high-level results testify that engineering students have sufficient employability potential, which largely indicates their competitiveness. The obtained low-level results indicate that the students are not yet ready to lifelong learn and develop professionally throughout his life, is not ready for changes in his chosen career, which indicates a certain inflexibility in thinking and acting. It is precisely these qualities that are very necessary in self-management of a sustainable career. This means that career support services should continue to be offered to promote career self-development and self-management under changing conditions (closely related to quantum transition theory). During the formative (pedagogical) experiment, significant and very significant changes occurred in students\u27 self-assessments according to the following criteria: students\u27 internal and external resources, competitiveness in the chosen profession (p value = 0.005 ... 0.018). This means that during the survey, the self-assessment of internal resources according to these indicators was influenced by the information obtained during the survey from the content of the questionnaire, which allowed for a more adequate self-assessment at the end of the experiment

CHARACTERISTICS OF MOTIONS IN FACING

In the process of work the tool angles change their value to become the working angles. This results in a variation of the work conditions of the cutting tools. The variation depends on the characteristic of the resultant cutting motion – the sum of the cutting motion and feed motion.In this article the characteristics of motions of facing are derived, which can serve as a basis for determining the relations between the tool and working angles.These relations can be used in programming the CNC to prevent the formation of negative working clearance angle and the destruction of the tool.

THE IMPACT OF RECESS BREAKS IN THE LEARNING PROCESS ON PRIMARY SCHOOL STUDENTS’ CONCENTRATION SKILLS

Nowadays one of the major problems in education is the lack of a specific strategy for the implementation of breaks (recess policy) in an educational institution. The development of such a strategy in the majority of cases is different for every school, as evaluating several factors is required, e.g., the age of students, interests, learning needs and progress, the location and specialization of the school, etc. However, students` awareness of the necessity for individual recess strategy gains importance as well. The research aim is to investigate and clarify the possibilities and necessity of recess breaks in primary school. There are theoretical research methods and empirical research methods (students’, teachers’ and parents’ surveys), data processing and analysis methods (quantitative, graphical representation of data, data analysis using IBM SPSS v.22 predictive analytics and statistical analysis software package) used in the research. The analysis of students’ survey emphasized that students more often prefer listening to music or socializing during breaks. While parents’ questionnaire highlighted the necessity for their offsprings to spend more time outside in fresh air. They mean it would help their children to better concentrate in lessons. While teachers` survey analysis revealed that students concentration is better if students are more interested in a particular subject

THE POSSIBILITIES OF DEVELOPMENT OF THE CHILD\u27S CREATIVITY AND ENTREPRENEURSHIP IN A PRE-SCHOOL

Today\u27s rapidly changing era and the resulting demands bring into focus aspects related to children\u27s education already from preschool, as this is the age when the basic qualities are formed and the foundations are laid for skills that are important for future development and self-fulfillment. The creativity and entrepreneurship of a preschool child is the ability to create new ideas and look for alternative solutions for their implementation, the readiness to act and finish what has been started, overcoming obstacles and showing initiative. The aim of the paper is to analyze the possibilities of development and assessment of the child\u27s creativity and entrepreneurship in a preschool educational institution. The paper identifies the criteria and indicators for the assessment of the child\u27s creativity and entrepreneurship, offers a model for the development of this skill in a preschool educational institution, and analyses the results of its approbation.

EFFECT OF CU AS МINORITY АLLOYING ЕLEMENT ON GLASS FORMING ABILITY AND CRYSTALLIZATION BEHAVIOR OF RAPIDLY SOLIDIFIED AL-SI-NI RIBBONS

The influence of copper as a minority alloying element in the process of rapid solidification of Al-Si-Ni ribbons produced by Chill Block Melt Spinning (CBMS) was investigated. XRD and TEM analyses proved a completely amorphous structure of the alloys Al74Ni16Si10 and (Al74Ni16Si10)98Cu2. The crystallization behaviour of these alloys was studied by DSC analysis. It was found that the crystallization of the amorphous alloys (Al74Ni16Si10)100-xCux, x=0, 2 runs in two steps. The temperatures Tx1 and Tx2 of each of the crystallization steps were determined. It was proven that the addition of 2 at. % copper does not significantly change Tx temperatures. The temperature difference ΔTx was calculated and it showed that more thermally stable is the copper containing alloy. Crystalline analogues of the amorphous alloys were obtained by annealing of the melt-spun amorphous ribbons at a temperature which exceeded by 170°C the onset crystallization temperature. The type and size of separated crystalline phases were determined by XRD. It was found that the addition of 2 at. % Cu to Al74Ni16Si10 alloy causes a separation of new phases - Cu3.8Ni and (Al, Cu)Ni3 and 54%, 24% and 7% size increase of the phases Al, Al3Ni, NiSi2 respectively