Экология

Composite materials based on wood filler are promising materials that are actively conquering the market. This is due to the advantages of using these materials in various fields: weather resistance and environmental compatibility, easy machining and possibility of recycling. Furthermore, it is sustainable use of wastes of timber sawing and furniture and woodworking industries, as well as low-grade wood. Wood powder is also known to be one of the components of consumables used in additive 3D printing technologies. Over the last decade, the commercial use of 3D printers has increased rapidly due to the fact that it allows creating prototype objects of complex shape based on a computer model. Experimental studies were carried out to determine the tensile strength and rheological properties of a composite made of polylactide 4043D, untreated wood powder brand 140 and wood powder thermally modified at 200 and 240 °C. The composite is intended for creation of three-dimensional objects by extrusion using a 3D printer. It was found that with an increase in the amount of filler in the composite, the tensile strength decreases. Also, samples with thermally modified filler show an increase in tensile strength in comparison with samples with untreated filler. Prototypes of 3D threads with different composition were obtained, during the study of which the melt flow index was examined. It was found that with increasing temperature of wood filler treatment the melt flow index increases. With a lower content of wood powder in the melt composition, there is a 2-fold increase in the melt flow index. The knowing of the rheological properties of the resulting compositions will allow achieving maximum performance and reduction of energy and production costs. For citation: Sabirova G.A., Safin R.R., Galyavetdinov N.R., Shaikhutdinova A.R., Khayrullin R.Z. Studying the Rheological Properties of a Polylactide Melt Mixed with Wood Filler. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 1, pp. 173–179. DOI: 10.37482/0536-1036-2021-1-173-179 Funding: The reported study was funded by RFBR, project number 19-33-90249
Композиционные материалы на основе древесного наполнителя, являясь перспективными, активно завоевывают рынок. это связано с преимуществами применения данных материалов в различных областях: стойкость к атмосферным воздействиям и экологичность, легкость механической обработки и возможность утилизации отходов. Кроме того, это и рациональное использование низкосортной древесины, а также отходов лесопиления, мебельной и деревообрабатывающей промышленности. Известно применение древесной муки в качестве одного из компонентов в аддитивных технологиях 3D-печати. За последнее десятилетие коммерческое использование 3D-принтеров возросло благодаря тому, что они позволяют создавать объекты-прототипы сложной формы на основе компьютерной модели. Проведены экспериментальные исследования по определению предела прочности на разрыв и реологических свойств композита из полилактида 4043D и термически обработанной при температуре 200 и 240 °С и необработанной древесной муки марки 140, предназначенного для создания трехмерных объектов методом экструзии с помощью 3D-принтера. Установлено, что с увеличением количества наполнителя в композите уменьшается предел прочности при растяжении, а также что по сравнению с образцами из необработанного наполнителя у образцов из термически модифицированного наполнителя наблюдается возрастание предела прочности. Получены опытные образцы различных по составу 3D-нитей, для которых был исследован показатель текучести расплава. Показано, что с ростом температуры обработки древесного наполнителя этот показатель повышается. При меньшем содержании древесной муки в составе расплава отмечается его увеличение в 2 раза. Знание реологических свойств получаемых композиций позволит достигнуть максимальной производительности, снизить энергозатраты и себестоимость готовой продукции. Для цитирования: Sabirova G.A., Safin R.R., Galyavetdinov N.R., Shaikhutdinova A.R., Khayrullin R.Z. Studying the Rheological Properties of a Polylactide Melt Mixed with Wood Filler // Изв. вузов. Лесн. журн. 2021. № 1. С. 173–179. DOI: 10.37482/0536-1036-2021-1-173-179 Финансирование: Исследование выполнено при финансовой поддержке РФФИ в рамках научного проекта № 19-33-90249.

Phytoplankton constitutes a key part of all aquatic ecosystems. It produces organic matter, thus forming the first level of food chains in water bodies. In addition, phytoplankton plays a major role in the water quality formation. The studies of algocoenosis always remain relevant, since the obtained data provides important information on the ecological status of water bodies. This information can subsequently be used for planning and implementing environmental measures, which are particularly significant for water bodies located in specially protected areas. National parks existing for the purposes of nature preservation, education and research are also designed for tourism, which makes their ecosystems more vulnerable. Population residing in such territories and its economic activity may also carry some environmental risks, which necessitates regular complex observations. This paper covers the state of spring phytoplankton community of Lake Kenozero in 2018, its qualitative and quantitative characteristics (species composition, abundance and biomass). In the course of research, we identified 70 phytoplankton taxa belonging to seven divisions: Bacillariophyta, Dinophyta, Chlorophyta, Cyanophyta, Chrysophyta, Xanthophyta and Euglenophyta. The dominant species complex included diatoms (Asterionella formosa, Melosira granulata, Tabellaria fenestrata), representatives of Dinophyta (Gymnodinium sp.), as well as small euglenoids. Species diversity was estimated using the Shannon-Weaver index. Aquatic environment contamination was assessed, i.e. the saprobity index was calculated and the class of surface water quality was determined. According to the water quality classification of water bodies and watercourses by hydrobiological indicators, Lake Kenozero was assigned the second class of water quality (moderately polluted).

Phytoplankton constitutes a key part of all aquatic ecosystems. It produces organic matter, thus forming the first level of food chains in water bodies. In addition, phytoplankton plays a major role in the water quality formation. The studies of algocoenosis always remain relevant, since the obtained data provides important information on the ecological status of water bodies. This information can subsequently be used for planning and implementing environmental measures, which are particularly significant for water bodies located in specially protected areas. National parks existing for the purposes of nature preservation, education and research are also designed for tourism, which makes their ecosystems more vulnerable. Population residing in such territories and its economic activity may also carry some environmental risks, which necessitates regular complex observations. This paper covers the state of spring phytoplankton community of Lake Kenozero in 2018, its qualitative and quantitative characteristics (species composition, abundance and biomass). In the course of research, we identified 70 phytoplankton taxa belonging to seven divisions: Bacillariophyta, Dinophyta, Chlorophyta, Cyanophyta, Chrysophyta, Xanthophyta and Euglenophyta. The dominant species complex included diatoms (Asterionella formosa, Melosira granulata, Tabellaria fenestrata), representatives of Dinophyta (Gymnodinium sp.), as well as small euglenoids. Species diversity was estimated using the Shannon-Weaver index. Aquatic environment contamination was assessed, i.e. the saprobity index was calculated and the class of surface water quality was determined. According to the water quality classification of water bodies and watercourses by hydrobiological indicators, Lake Kenozero was assigned the second class of water quality (moderately polluted). Citation: Otchenash NG, Dvoryankin GA, Imant EN (2019) State of spring phytoplankton and quality of the Kenozero waters in 2018. Arctic Environmental Research 19(1): 43–48. https://doi.org/10.3897/issn2541-8416.2019.19.1.43