ПОРІВНЯЛЬНА ХАРАКТЕРИСТИКА ЕФЕКТИВНОСТІ ЕЛЕКТРОХІМІЧНИХ МЕТОДІВ ДОСЛІДЖЕННЯ ВМІСТУ ВАЖКИХ МЕТАЛІВ У СТІЧНИХ ВОДАХ

Сompare the various modern electrochemical research methods effectiveness used to determine the heavy metals concentration in waste water, based on the literature data. Methodology. Analysis of literature data on the possibilities, advantages and disadvantages of voltammetric, potentiometric, coulometric and conductometric methods for the heavy metals content studying in waste water. Findings. The electrochemical methods are the most common methods for analyzing the composition of waste water. Among their advantages, it should be noted high selectivity, low concentration registration limit (up to 10-10 M for stripping voltammetric methods), simplicity in execution, absence of preliminary long-term samples preparation for analysis, the ability to microvolumes measure without samples destroying and automation of the process for continuous metals concentrations determination in waste water treatment, relatively inexpensive equipment, the ability to determine the concentration of several metal ions in a mixture. Originality. The studies have shown that most often the concentration of heavy metals in waste water determine with the using of the different modifications of voltammetric research methods (polarography and varieties of stripping voltammetry) and potentiometric research methods in particular with highly sensitive and specific ion-selective indicator electrodes. Practical value. The theoretical material on modern electrochemical methods for the heavy metal ions content determining in waste water is generalized.

КІНЕТОСТАТИЧНЕ ДОСЛІДЖЕННЯ ШАРНІРНИХ ПРОСТОРОВИХ МЕХАНІЗМІВ ГАЛТУВАЛЬНИХ МАШИН (ЧАСТИНА 1: ДОСЛІДЖЕННЯ МЕХАНІЗМУ З ДОДАТКОВОЮ РУХОМОЮ ЛАНКОЮ – КОРОМИСЛОМ)

Kinetostatic study of a statically determined hinged spatial mechanism without redundant (passive) connection with an additional movable link – a rocker arm of a machine for processing parts, in which the working container performs complex spatial movement. Methodology. The essence of the kinetostatic research was to determine the radial and axial components of the reactions in all rotational kinematic pairs of the hinged statically defined spatial mechanism of the machine for processing parts, when it is idling. The kinetostatic study was implemented using the SolidWorks 2016 computer-aided design system with preliminary 3D modeling of this machine design with an additional moving link – a rocker. Results. In the course of the kinetostatic study, 3D modeling of a machine with an additional movable link – a rocker arm in the SolidWorks 2016 computer-aided design system was carried out, the maximum values of the radial and axial components of reactions in all rotational kinematic pairs of the machine for processing parts were determined, the effect of changing the center distance of the intermediate connecting rod (working capacity ) on the increase in the maximum values of the reactions in all rotational kinematic pairs. Scientific novelty. The relationship between the center distance of the intermediate connecting rod (working capacity) and the change in the maximum values of the reactions in all rotational kinematic pairs of the machine for processing parts is determined. As a result, it becomes possible to determine the maximum permissible center distance of the intermediate connecting rod to ensure the durable operation of the machine. Practical significance. It is determined that the nature of the change in the maximum values of the radial and axial components of the reactions in each rotational kinematic pair of the spatial mechanism depends on the value of the coefficient characterizing the ratio of the center-to-center length of the intermediate connecting rod (working capacity) to the center-to-center length of the driving or driven connecting rods of the machine. The range of variation of this coefficient has been determined, within which it is rational to design this machine design. The results obtained can be used in the corresponding design bureaus of machine-building enterprises at the stage of designing tumbling equipment with a complex spatial movement of working containers.

ОСВІТЛЕННЯ ВХІДНОЇ ГРУПИ З ЕЛЕМЕНТОМ РЕЖИМУ ОЧІКУВАННЯ ДЛЯ ЗАКЛАДІВ ЦІЛОДОБОВОЇ РОБОТИ

The main purpose of the study is to create energy-efficient solutions when designing the lighting of the entrance group for the case when the object must provide round-the-clock operation Methodology. To achieve this goal, a method for multi-level connection of light sources of different intensities has been developed. The control of the processes of level regulation is carried out using motion sensors. Results. The modern level of LED products makes it possible to use LED lighting sources as universal ones, allowing you to implement any design solution. The introduction of motion sensors as elements for regulating the intensity of light allows to obtain more than 50% energy savings. Interesting design solutions help create light accents without creating too much lighting on certain objects. Scientific novelty. The work combines multilevel lighting systems using motion sensors as switches operating at night. The authors proposed a sequence of connecting the levels of the system to create the most comfortable stay and a good first impression of the institution. Such a system makes it possible to use lighting not only for practical purposes, but also for the most attractive visual appearance. Practical significance. The versatility of this methodology allows it to be applied to objects of various purposes, including round-the-clock service. However, it is important to plan for such a lighting system even at the design stage of the building in order to obtain the maximum economic benefit.

РОЗРОБКА АЛГОРИТМУ ЗАГАЛЬНОЇ СТРАТЕГІЇ АВТОМАТИЗАЦІЇ ВИБОРУ КУРСУ УХИЛЕННЯ СУДНА

During ships maneuvering, the main cause of accidents is that navigators do not always objectively assess the situation and may make wrong decisions on the identification situation of a dangerous approach and a collision hazard. The automation of the deviation course choice is considered as the automation avoidance process. Purpose. The article highlights the tasks of formalizing the deviation course as a value of automatic control, and proposes the development of an algorithm for the strategy of changing the course. Methodology. Conducted processing of practical data of own vessel. The existing models of the ship's movement were analyzes, as well as the systems for the automatic stabilization of the ship. To construct the algorithm, the COLREGs–72 was decomposed with respect to the belonging of the initial situation of the vessels to one of the areas of mutual obligations. Findings. According to the results of the given theme, an algorithm of the general strategy of choosing the course of evasion of the vessel was developed, considering the requirements of COLREG–72 rules. It were considered the types of control of automatic regulators and their limitations at the initial and final moments of the ship's turn. It was found out. It is necessary to create a multilevel mathematical description, which will include subsystems of different levels, to build a model of an integrated control system. Originality. It was determined the efficiency of using the principle of execution of ship’s turns by the method of observation with a given influence by analyzing the existing models of ship’s movement. It was offered to use the range of acceptable values of courses during the development of the model of automation ship avoidance process. Practical value. An algorithm for the general strategy of automation of the avoidance course selection was developed.

КАРКАСНА МОДЕЛЬ ОДНООСНОГО РОЗТЯГУВАННЯ КУЛІРНОГО ТРИКОТАЖУ ВЗДОВЖ ПЕТЕЛЬНИХ СТОВПЧИКІВ

The purpose of this study is to develop a frame model for stretching the weft-knits in the wale direction, suitable for further integration into the algorithm for building a three-dimensional knitwear model in a stretched state and modeling of interactive deformation dynamics. Methodology. Methods of theoretical analysis, basics of knitting theory, topological model of knitwear, methods of geometric modeling and parameterization were used in the research process. Findings. Modeling the physical and mechanical behavior of knitwear in a computer environment is one of the promising ways to increase the level of conformity of knitted products with the requirements of comfort and functionality. However, the complexity of the internal structure, the anisotropy of properties and the instability of the parameters of the loop structure determine the need to find non-trivial ways to solve the problem of mathematical description of the three-dimensional model of the thread, knitted in the knitwear, considering the stretching deformations. During the study, a frame model of a uniaxial stretching of knitwear in the wale direction was developed. The basis of the frame model is the idea of a knitted structure, represented as a logically organized set of elements, each of which is interlaces with other elements in accordance with the topology of knit. The frame of the jersey fragment is described as a set of bars and hinges. The hinges are located at the interlacing points of the loop heads and loop feet, and each rod in the model is an imaginary element representing a complex of force factors that prevent the change of distance between the hinges connected to the given rod. In the process of stretching, the geometrical characteristics of the elements change, while the logical connections remain unchanged. The wireframe model allows to define coordinates of interlacement points in the coordinate system of the sample, relative position of coordinate systems of each elementary fragment, which correspond to given loops, coordinates of characteristic points of a loop for transition to a three-dimensional model of a knitted structure. Scientific novelty. For the first time, a frame model of deformation of the knit, suitable for three-dimensional modeling of its structure, considering deformation of the thrust, was developed. Practical value. The developed model can be used as mathematical support of systems of automated designing of knits.

УДОСКОНАЛЕННЯ ПРОЕКТУВАННЯ ТЕХНОЛОГІЧНОГО ПРОЦЕСУ ТОЧНОГО ОБ’ЄМНОГО ШТАМПУВАННЯ ВИДАВЛЮВАННЯМ НА ОСНОВІ РОЗВИТКУ ЕНЕРГЕТИЧНОГО МЕТОДУ БАЛАНСУ ПОТУЖНОСТЕЙ

Improvement of technology design in precision forging process based on development of energy method with power balance and development of recommendation with the rational use of systematized based on kinematic modules in complex configuration to make calculated schemes for power mode assessments and shaping of part in cold forging extrusion process with subsequent software implementation are considered. Methodology. Energy method of power balance is considered based on kinematic module method that will be systematized the results of investigation for expanding in cold forging extrusion process with the definition of the power mode in deformation and features of semi-finished product shaping to make hollow and rod parts with flange such as sleeves and glasses. Results. Development results of recommendation with the rational use of systematized based on kinematic modules in complex configuration to make calculated schemes including with the ability to quickly take into account changes in the configuration of the tool have been determined. This made it possible to define the several factors for controlling the shaping of the semi-finished product in combined and sequential combined cold forging extrusion processes. Scientific novelty. Energy method of power balance is considered such as an effective method of preliminary analysis to determine the area of rational use in cold forging process based on process technology design to make complex parts. Practical significance. Software product development with extended systematization based on kinematic modules, complex of calculation models in cold forging extrusion with power mode assessments and to predict shaping of part and defect formation such as dimple defect will contribute more active implementation in the manufacturing industry for combined cold forging extrusion processes.

ПІДВИЩЕННЯ ВОГНЕЗАХИСНОЇ ЕФЕКТИВНОСТІ ІНТУМЕСЦЕНТНИХ ЕПОКСИДНИХ ПОКРИТТІВ СПОЛУКАМИ ІНТЕРКАЛЬОВАНОГО ГРАФІТУ

Investigation of the effect of nitrate oxide graphite on the parameters of char layer, obtained from the system of ammonium polyphosphate / melamine / pentaerythritol / epoxy resin under the influence of temperatures of 200–800 °С. Methodology. A fire retardant mixture was chosen as a model intumescent system ammonium polyphosphate / melamine / pentaerythritol. As a polymer component was used bisphenols A / F epoxy resin together with a polyamidoamine hardener. Nitrate oxide graphite was obtained by oxidation of natural scaly graphite with fuming nitrogen acid. The effect of impurities of nitrate oxide graphite was determined by thermogravimetry on the intumescence coefficient of intumescent compositions and the mass of the char residue intumescent compositions in temperature range of 200–800 °С. Findings. The influence of nitrate oxide graphite on the characteristics was studied of char layer of epoxy intumescent system ammonium polyphosphate / melamine / pentaerythritol / epoxy resin. The study of thermal oxidative degradation was carried out intumescent compositions in the temperature range 200–800 °С. It was shown that intercalated graphite compounds increase the thermal stability of the formed char layer at temperatures > 600 °С. Determined intumescence coefficients and thermogravimetric analysis of modified intumescent systems was performed nitrate oxide graphite with different degrees of intercalation, in the conditions of 200–800 °С. It was established that the optimal parameters of the char layer are in terms of volume intumescence coefficient and mass of the char residue are provided by graphites, which contain 15–25% of intercalant in its composition. But the results obtained allow us to determine nitrate oxide graphite as a promising modifier of epoxy intumescent systems to increase its fire protection efficiency. Originality. The influence of degree of intercalation of nitrate oxide graphite was studied on the characteristics of char layer of epoxy intumescent system for the first time. Practical value. The optimal content of intercalant in nitrate oxide graphite was established for the development of formulations of intumescent epoxy coatings with increased fire retardant properties.

ЕРГОНОМІЧНІ ПОКАЗНИКИ ТРИКОТАЖУ ТА ЇХ ЗВ'ЯЗОК З ГЕОМЕТРИЧНИМИ ХАРАКТЕРИСТИКАМИ

The purpose of this study is to analyze the ergonomic properties of knitwear, that form sense of thermophysiological comfort of a person and their connection with the geometric characteristics of the knitted structure to study the prospects of comfort predicting using computer-aided design systems. Methodology. During the research methods of theoretical analysis, basics of the theory of knitting, theories of thin elastic shell, basic concepts of mechanics and the basics of hydrodynamics were used. Findings. In the course of the work a theoretical analysis of scientific works and normative and technical documentation on various aspects of the definition and provision at the required level of ergonomic properties of knitwear that characterize the level of its convenience and comfort has been carried out. It was found that many researchers refer as most influencing the sense of comfort such properties as: air permeability, water vapour permeability, thermal resistance, hygroscopicity, electrical resistance, as well as stiffness and stretchability, that most affect the ability of knitwear to keep shape and fit the size of the human body. It was found that all abovementioned knitwear properties depend on the geometric characteristics of the knitted structure, such as yarn diameter; the loop length; wale spacing; course spacing; the thickness of the knit and others. Theoretical models of mechanical and physical properties of knitwear are functions of the geometrical characteristics of its structure, therefore the quality prediction of physical behaviour of knitwear depends on the quality of the 3D geometric model of the yarn, knitted in the knit. Scientific novelty. As a result of an analytical review of scientific publications and normative and technical documentation, the ergonomics of knitwear that form a feeling of thermophysiological comfort were determined, and their connection with the geometric characteristics of the knitwear structure was established. Practical value. Theoretical models of air permeability, thermal conductivity and stretchability, published in scientific journals, from the point of view of the possibility of their use as the basis for mathematical support of the computer-aided design system of knitted clothing are analyzed.

ВИЗНАЧЕННЯ ВПЛИВУ ЛАЗЕРНОГО ГРАВІРУВАННЯ НА ГІГІЄНІЧНІ ВЛАСТИВОСТІ НАТУРАЛЬНИХ ШКІР ДЛЯ ВЕРХУ ВЗУТТЯ ТА ШКІРГАЛАНТЕРЕЙНИХ ВИРОБІВ

Purpose. Investigation of the effect of laser engraving on the hygienic properties of nature leather for uppers and leather goods, namely leather Krast, Flotar and Nappa. Methodology. To achieve this goal, the method of scanning electron microscopy (SEM) was used. Hygienic properties of Krast, Flotar and Nappa hides was studied in accordance with ISO 14268: 2008 by determining vapor permeability. Findings. According to the results of the study of the effect of laser radiation on the hygienic properties of nature leather for uppers and leather goods, the nature of changes in the micro- and macrostructure of the dermis under laser engraving and allowable depth and area of laser ablation that do not impair the hygienic properties of these skins and products. With increasing ablation depth to 0,7 mm (50% of the total thickness of the sample), the relative vapor permeability increases in all samples of the studied skins, while the relative vapor permeability for the skin of Krast increased by 5%, Flotar by 13,5% and 9,5% for Nappa. The optimal value of the depth of laser ablation, which does not impair the operational and hygienic characteristics of the products is 25–30% of the skin thickness. On the front surface revealed features of the structure, which are characteristic only for the area of direct action of the laser beam, namely the skin samples Flotar and Nappa have obvious signs of welding collagen fibers. In the area of laser ablation, an increase in the interstructural distances between the bundles of collagen fibers was also detected, which was the result of thermophysical processes of laser radiation. Originality. The determined effect affects the depths and flat laser ablations on the morphological structure of the dermis and the hygienic properties of natural leather for shoe uppers and leather goods. Practical value. The vapor permeability of genuine leather for the uppers of shoes and leather goods under the action of laser radiation was determined. The value of the depth and area of laser ablation for finishing leather products, taking into account the impact on the hygienic properties of products in general.

ДОСЛІДЖЕННЯ ЕКРАНУЮЧИХ ВЛАСТИВОСТЕЙ ТЕКСТИЛЬНИХ МАТЕРІАЛІВ ЩОДО ДІЇ УЛЬТРАФІОЛЕТОВОГО ВИПРОМІНЮВАННЯ

Study the possibility of using textile materials for shielding against the negative effects of ultraviolet radiation. Methodology. Theoretical and experimental researchs are based on the basic principles of textile materials science. The UV shielding ability of textiles was assessed by the UV protection factor (UPF). The UV protection factor was evaluated on a UV-Vis spectrophotometer (Cary 50, Varian, Australia) in accordance with AS / NZ 4399: 1996 in the wavelength range 280-400 nm. According to AS / NZ 4399: 1996, textiles are classified according to the value of the UV protection factor (UPF) as those that provide "excellent UV protection", "very good UV protection", "good UV protection", "does not protect against UV radiation." Results. The main sources of UV radiation are analyzed and the features of the conditions of human exposure when working indoors and outside are considered. It has been established that the degree of human exposure depends on the intensity of UV radiation, and can be reduced by using protective equipment. Flexible textile screens can be one of the effective means of protection against UV radiation. The advantages of textile screens are the possibility of their modification and the ability to create shielding products of various shapes. The level of protective properties of textile screens depends on many factors, namely: the chemical nature of the polymer of textile materials, structural characteristics, modification by certain substances, color, moisture, etc. The results of the study of the coefficient of protection against ultraviolet radiation of textile materials, depending on their color are presented. Scientific novelty. It is proved that the optical properties are not only important for the evaluation of appearance of the textile and garment aesthetic perception, they can control the shielding properties of the textile to the action of UV radiation. It was found that dark saturated colors of textile fabrics, all other conditions being equal, provide shielding properties at the level of "very good protection" compared to light unsaturated colors (the UPF level varies from 10 to 35 with increasing color saturation). Practical value. The possibility of using textile materials for UV protection has been confirmed.