Kurylyak V.V.,Kyiv National University of Technologies and Design |
Khimicheva G.I.,Kyiv National University of Technologies and Design
Uspehi Fiziki Metallov | Year: 2017
Since in a contemporary metrological database, there is no clear method for evaluation of the quality of materials under high and shock loads, this article presents results of experimental studies of practical application of qualimetric methods for evaluation of the quality of materials under such conditions. The analysis of the characteristics of materials under shock loads is performed along with qualimetric methods, which are adapted for evaluation of the quality of high-loaded materials. Criteria for evaluation of quality of materials under extreme loads are determined. The algorithm and methodical recommendations for evaluation test of materials are developed along with realization of practical implementation of developed recommendations. The algorithm for performance of evaluation test for materials is presented and specifies a choice of test method for determining necessary qualimetric methods of the quality evaluation. Based on experimental data, it is established that the most appropriate for practical application is using so-called 'cobweb' of quality as a primary qualimetric method. In addition, one can use methods of pie charts and construction of the ranked data. The quality evaluation with a price ratio is quite effective for the market and competing materials such as metals and steel. For an impulsive load, the qualimetric evaluation method such as the construction of nomograms is effective. The problem of the quality gradation development, which is basic during the construction of nomograms, is solved.
Koval'chuk A.V.,Kyiv National University of Technologies and Design |
Shevchuk A.F.,Vinnitsa National Agricultural University
Journal of Nano- and Electronic Physics | Year: 2017
The existing methods for measuring the magnitude of spontaneous PS polarization in ferroelectric liquid crystals are analyzed. It is shown that the above methods do not allow a sufficient PS measurement accuracy, as a result of the available active component of conductivity due to the influence of their own or deliberately introduced impurities. A modified method of PS measuring value by means of a triangular voltage signal is suggested. The difference of this method of PS measuring value from other methods is that not the charge in the vicinity of the peak current is analyzed, caused by the repolarization process, but the value of the maximum current. It is shown how this method eliminates the currents analysis caused by the presence of different types of impurities. © 2017 Sumy State University.
Tomylko S.,Ukrainian Academy of Sciences |
Yaroshchuk O.,Ukrainian Academy of Sciences |
Koval'Chuk O.,Kyiv National University of Technologies and Design |
Lebovka N.,Ukrainian Academy of Sciences
Physical Chemistry Chemical Physics | Year: 2017
Structuring of carbon nanotubes (CNTs) in liquid crystals (LCs) and electro-physical characteristics of LC + CNT suspensions were studied in a very broad range of CNT concentrations, C, from 10-5 wt% (highly diluted suspensions) to 2.5 wt% (highly viscous suspensions). Along with the conventional sandwich cells with the transparent electrodes on the substrates, we used the cells with the in-plane applied electrical field in order to monitor changes of electrical parameters in the same direction as the structural changes observed under an optical microscope. The data revealed four stages of structural evolution with the increase of C: (1) dispersion of individual CNTs and their very small aggregates (C < 3 × 10-4 wt%), (2) presence of branched aggregates with a non-compact structure (C = 3 × 10-4-5 × 10-3 wt%), (3) percolation of non-compact aggregates (C = 5 × 10-3-10-1 wt%) and (4) compaction of aggregates and formation of a dense network (C = 10-1-1 wt%). In the studied concentration range, the conductivity displayed two percolation thresholds at C1p ≈ 0.004 wt% and C2p ≈ 0.5 wt%, which are associated with the formation of a non-compact and dense CNT network. By contrast, the permittivity ε′ revealed only one percolation threshold at C2p ≈ 0.5 wt%, when the distance between the adjacent CNTs becomes incredibly small. © the Owner Societies 2017.
Glubish P.A.,Kyiv National University of Technologies and Design
Polymer Science - Series D | Year: 2013
Findings on the effect of neutralizing substances on rheological properties of products of the destruction of collagen-containing materials are presented. The dependences between the shear velocity and shear stress and between shear stress and viscosity of the products of alkaline destruction of collagen-containing materials neutralized by different acids are established. © 2013 Pleiades Publishing, Ltd.
Halavska L.,Kyiv National University of Technologies and Design |
Batrak O.,Kyiv National University of Technologies and Design
IOP Conference Series: Materials Science and Engineering | Year: 2016
A new trend in the world is the clothing production using the new types of ecological raw materials application - milk, pineapple, coconut, hemp, banana, eucalyptus, clams, corn, bamboo, soya, nettle yarn. This makes it possible to create textile materials of new generation with unique antibacterial and antiseptic properties. Such materials have a positive preventive and sometimes therapeutic effect on people, and their health. Eco-raw materials clothing is able to protect the human body from the environment harmful effects: cold, heat, rain, dust, opportunely remove from underclothing layer the steam and gases, sweat; maintain in underclothing layer the necessary microclimate for normal organism functioning. Study of knitwear consumer properties, produced with eco-materials, is an urgent task of the world vector, directed on ecological environmental protection. This paper presents the research results of hygroscopicity and capillarity weft knitted fabrics, what knitted from different types of eco-raw materials: bamboo yarn, yarn containing soybean and nettle yarn. Character of influence of the liquid raising level changes depending on the experiment time and the knitting structure is revealed. © Published under licence by IOP Publishing Ltd.
Kyzymchuk O.,Kyiv National University of Technologies and Design |
Melnyk L.,Kyiv National University of Technologies and Design
IOP Conference Series: Materials Science and Engineering | Year: 2016
The features of elasticized knitted fabric are: high extensibility, elasticity and adaptability to a body shape and a compression effect when it is used in the extended state. The elasticity of a knitted fabric is enhanced by the incorporation of elastane thread or core-spun yarn into the knitted structure as the weft yarn that is laid in the stretching direction. The quality of elasticized knitted fabrics is determined by the reliability of the how the elastomeric yarn is fixed within as the structure is deformed with an increase in the contact areas between the elastomeric and conventional yarns. The high fixing level can be achieved by the nature of loops formed from the elastomeric yarn. The simultaneous union of both conditions is possible with miss-knitting of elastomeric yarn through a certain number of needles. The main purpose of this study is to establish the influence of miss knit repeat of elastomeric yarn on the structural parameters and determine the stretch properties of the elasticized knitted fabric that formed by an alternation of two courses of 1x1 rib from cotton yarn and one course of miss knit (from 2 to 10 Wales between the loops) from core-spun yarn with elastane core. © Published under licence by IOP Publishing Ltd.
Kozar O.P.,Mukachevo State University |
Oliynykova V.V.,Kyiv National University of Technologies and Design |
Konoval V.P.,Kyiv National University of Technologies and Design
Key Engineering Materials | Year: 2013
The aim of this study is to improve the heat resistance performance of polyurethane based adhesives for the manufacture of shoes. Four polyurethane adhesive compositions most used in the domestic shoe industry have been investigated: PU-503, VU-252, KYSPO-1 and D-274. The main components of polyurethane compositions are urethane rubber, zeolite, ethyl acetate and acetone. It has been found that modification of VU-252, KYSPO-1 and D-274 with zeolite in the amount of 0.5-1% allow to increase the heat resistance to 150° C while that of PU-503 - to 200° C. Besides it has been found that adhesive compositions can be recommended for the manufacture of special fire-resistant shoes that could withstand high thermal loads. © (2013) Trans Tech Publications, Switzerland.
Kuznetsova E.,Kyiv National University of Technologies and Design
Metallurgical and Mining Industry | Year: 2015
The options for improving energy efficiency of a standard residential building built in 1960s were investigated and analyzed and the structure of the heat losses of the building prior to and after the thermal renovation was determined. Thermal renovation of buildings leads to significant cost savings for space heating. Thus, the implementation of energy-efficient solutions for the analyzed building can lead to the following achievements: replacement of windows by more energy efficient ones leads to a reduction in heating energy consumption by 14,7%; insulation of external walls with bringing resistance to heat transfer to the normative values reduces heat losses by 40,4%; the most quantity of heat energy conservation (76,8%) is achieved by the integrated approach (external building envelope insulation, installation of energy efficient windows, refurbishment of the heating system). Knowing the value of investments in energy saving measures, the payback period can be calculated as well as the optimal energy-saving solution can be determined. The analysis and comparison of different energy saving solutions can be used to identify ways for further upgrading of buildings.
Mokrousova O.,Kyiv National University of Technologies and Design
Proceedings of the 3rd International Conference on Advanced Materials and Systems, ICAMS 2010 | Year: 2010
The organo-mineral compounds with bentonite and lignosulfonats for retanning-filling leather semi-finished item were offered. The use of obtained organo-mineral compounds allows increasing the formation of derma volume and leathers resistance to mechanical actions.
Avdonin K.V.,Kyiv National University of Technologies and Design
Journal of Nano- and Electronic Physics | Year: 2015
The paper describes relative one-dimensional motion of two relativistic particles: electron and neutral particle in a weak uniform electric field directed along their common moving direction. Motion is considered in two reference frames: inertial and noninertial associated with an electron. A method for obtaining the transformation of coordinates is proposed. An example of application of the obtained equations is shown. Desired limits are specified. © 2015 Sumy State University.