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Impact of Water on Rheological Behavior of Polyurethane Glues
2016
Laiveniece, Laura | Morozovs, Andris
Gluing of wood with great moisture content has challenge of water interaction with glue to give unwanted changes in glue properties and formed bond-line. Rheological measurements of polyurethane glues are sufficiently effective method to understand the polymer curing process and viscoelastic properties. Gel formation point is important parameter for a glue from the point of its application. When glue reaches the gel formation point, its viscosity drastically increases so that it could not properly wet the wood and it can result in poor bonds. One-component moisture curing polyurethane glues require water molecules for the polyadditional reaction. When water is involved in the curing reaction, it reacts with the isocyanate groups of glue and can lead to the formation of excessive carbon dioxide and thus can lead to glue penetration out of bond-line, additional backpressure. The dynamic viscoelastic parameters such as complex dynamic viscosity (ή), phase angle (δ), elastic storage modulus (G”), the viscous loss modulus (G”) of two kinds of polyurethane glues depending on added water amount (from 0.9% to 10.0%) at a constant frequency and deformation (oscillation mode) were determined using rheometer. The aim of the present study was to investigate impact of added water on rheological behavior of polyurethane glues. At the end of this study it was concluded that tested glues indicated various behavior depending on chemical composition and added water content. Gel formation point is higher in case of GlueI. However, gel formation time was higher in case of GlueII and was not dependent on added water content. Gel formation time was faster for GlueII. Nevertheless, faster formed gel is stronger than longer formed gel of GlueI.
اظهر المزيد [+] اقل [-]State decoupling audit of low-carbon agricultural production
2021
Datsii, O., Interregional Academy of Personnel Management, Kiev (Ukraine) | Levchenko, N., National Univ. Zaporizhzhia Polytechnic (Ukraine) | Shyshkanova, G., National Univ. Zaporizhzhia Polytechnic (Ukraine) | Dmytrenko, R., Vinnytsia National Agrarian Univ. (Ukraine) | Abuselidze, G., Batumi Shota Rustaveli State Univ. (Georgia)
It is stated that the strategic benchmark for transformational changes in the economy is currently low-carbon production, the achievement of which is possible to provide with the consistent application of an arsenal of strict control measures, in particular, the introduction of state audit of low-carbon production. The effectiveness of the mechanism for ensuring the implementation of the UN Framework Convention on Climate Change has been assessed. The necessity of implementation in the domestic practice of the state audit of low-carbon production by the decoupling approach is proved. The agri-business portfolio has been formed according to the decoupling approach as one of the leaders in greenhouse gas pollution. The author's economic and mathematical models of estimation according to the decoupling approach of the impact of branches of crop and livestock production on environmental pollution are proposed. The dependence of greenhouse gas emissions on the volume of gross output of agricultural production, capital investment and current expenditures on environmental protection has been established. The results of a comparative analysis of the realism of forecasts of changes in greenhouse gas emissions according to the methodology of the National Academy of Sciences of Ukraine and the author's methodology are highlighted. A roadmap for the introduction of a state low-carbon decoupling audit of the state decoupling audit has been proposed as part of the preparation of the second nationally determined contribution to the Paris Agreement. The expediency of supplementing GRI 300 “Environmental Disclosures” with the group of indicators GRI-305.5 “Reduction of GHG emissions”, formed by the decoupling approach, is substantiated.
اظهر المزيد [+] اقل [-]Global trends of decarbonisation as a determining factor for the development of external economic activity of metallurgical enterprises
Levchenko, Nataliia | Shyshkanova, Ganna | Abuselidze, George | Zelenin, Yuriy | Prykhodko, Volodymyr | Kovalskyi, Maksym
The article states that in the conditions of climate crisis aggravation the decarbonisation of the economy acquires the status of a global initiative aimed at achieving zero CO2 emissions by 2050. It is emphasised that this initiative is closely accompanied by legislation, business modernisation programmes and the creation of equal conditions for both domestic producers and exporters of carbon-intensive products (in particular, through the introduction of the carbon border adjustment mechanism – CBAM) and new rules of the world market. The consequences of CBAM implementation into Ukrainian metallurgical enterprises and the development of their foreign economic activity are determined in the example of Metinvest Group (Ukraine) enterprises. The ambivalence of CBAM is proven. It is substantiated that CBAM implementation will not accelerate, but, on the contrary, will slow down the process of decarbonisation, which will eventually lead to the loss of domestic metallurgical enterprises’ competitive position in the European market of metal products. Regarding the need to take transitional measures to decarbonise the metallurgical business (first of all, to ensure proper investment), the decision should be based on the expected decoupling effect – positive dynamics of economic growth while reducing the negative impact on the environment. The estimating method of the decoupling effect has been modified according to the integrated approach. A trend analysis of the integrated decalin effect indicator and its components was performed in Metinvest Group companies (Ukraine). Based on the results of econometric analysis of the impact of investment on greenhouse gas emissions, the author’s model for determining the volume of investment in the process of decarbonisation of metallurgical enterprises for the period up to 2050 is proposed. Comparative analysis is performed regarding investment in the process of decarbonisation under the scenarios by GMK Center, IEA, McKinsey and Roland Berger, as well as the author’s model.
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