Stable superhydrophobic wood surface constracting by KH580 and nano-Al2O3 on polydopamine coating with two process methods

Author(s):  
Jisheng Yang ◽  
Han Li ◽  
Zede Yi ◽  
Murong Liao ◽  
Zhiyong Qin
Keyword(s):  
Author(s):  
Aleksandr Chemodanov ◽  
Evgenii Iamshchikov ◽  
Roman Lozhkin ◽  
Aleksandr Turuev

Author(s):  
И.В. Коваленко ◽  
М.А. Чубинский ◽  
Д.С. Русаков ◽  
Г.С. Варанкина

Применение древесины осины в промышленном производстве материалов и изделий ограничено из-за ее низких механических свойств, подверженности поражению коррозионно-деструктивной гнили, отсутствием должного обоснования технологии ее переработки. Невостребованная осина осложняет условия хозяйствования в лесу, ухудшает породный состав древостоев, препятствует восстановлению хвойных пород древесины. Древесина осины хуже смачивается водой по сравнению с другими породами. Изучение ее поверхностных свойств и строения на микроуровне представляет безусловный интерес для изучения взаимодействия древесины с водой, жидкими клеящими и защитно-декоративными веществами. Это сложная многопараметрическая задача, решение которой может явиться новым инструментом для обоснования наукоемких технологических процессов сушки, пропитки, склеивания и облагораживания древесины. Истинная поверхность древесины, образованная в результате обработки резанием (лущением, пилением, фрезерованием) значительно больше ее проекции на плоскости в результате разрезания микроструктурных элементов. Неровности на поверхности искажают результаты измерения поверхностных свойств, определяемых на основе угла смачивания. Учитывая то, что размеры стенок клеток меньше размеров полостей, истинная площадь поверхности древесины, в зависимости от вида разреза, может в десятки раз превышать кажущуюся. Ухудшение способности смачиваться объясняет образование на поверхности капель клея, нанесенного на шпон методом вальцевания. При горячем прессовании фанеры в первый момент времени повышается подвижность молекул клея, снижается упругость древесины, поверхность выравнивается, улучшая условия адгезионного взаимодействия связующего и древесины. Для определения истинных характеристик древесины, обоснования расхода клея, способности древесины поглощать жидкость необходимо знать размеры ее микроструктурных элементов и характер их распределения, объем поверхностных полостей. Эффективный радиус полостей древесины осины может быть описан с использованием теории фракталов. The use of aspen wood in manufacturing of materials and products is limited due to its low mechanical properties, corrosion susceptibility destructive lesion decay, its lack of proper justification processing technology. Unclaimed aspen difficult economic conditions in the forest, degrades the species composition of forest stands and prevents restoration of softwood. Wood aspen worse moistened with water compared to other breeds. The study of its structure and surface properties at the micro level is of great interest to study the interaction of wood with water, liquid adhesives and protective-decorative materials. This is the problem whose solution can be a new tool for the study of science-intensive technological processes of drying, impregnation, gluing and surface finishes. Real wood surface, formed by the machining (peeling, sawing, milling) significantly greater its projection on the plane as a result of cutting the microstructural elements. Surface irregularities distort the results of measurement of surface properties which are determined based on the contact angle. Given that the size of the cell walls is less than the size of the cavities, the true surface area of the veneer, depending on the type of incision, may be ten times the apparent. The deterioration of the ability of wetted explains the formation of droplets on the surface of adhesive deposited on the veneer by rolling. When plywood hot pressing at a first time increases mobility of adhesive molecules, decreases the modulus of elasticity of wood, surface is aligned, improving the conditions of interaction of the glue and the wood. To determine the true characteristics of the wood, glue flow study, the ability of wood to absorb liquid it is necessary to know the size of microstructural elements and their distribution, the amount of surface cavities. The effective radius of aspen wood cavities can be described using fractal theory.


2021 ◽  
Vol 55 (2) ◽  
pp. 565-583
Author(s):  
Ke Zhan ◽  
Quanxiong Lu ◽  
Sengwei Xia ◽  
Congnan Guo ◽  
Sisi Zhao ◽  
...  

Author(s):  
M. Jurek ◽  
R. Wagnerová

AbstractLaser engraving of photographs on wood surfaces is a challenging task. To optimize the outcome and production quality it is necessary to control every aspect of the laser engraving process. Most of the production machines and technologies overall are mainly focused on laser power control. However, with other systems and deeper knowledge of the wood characteristics it is possible to achieve even better quality. This paper deals with enlarging the number of achievable shades of burned wood and its optimization. A calibration system was developed to control colour shades of engraved wood with a combination of laser power and optic focus. With this approach it is possible to widen achievable palette of engraved shades by continuous control of chemical processes of laser and wood interaction. The production is divided into wood burning and wood carbonization by variation of laser beam focus.


Polymer ◽  
2021 ◽  
pp. 123942
Author(s):  
I. Zaborniak ◽  
A. Macior ◽  
P. Chmielarz ◽  
J. Smenda ◽  
K. Wolski

2018 ◽  
Vol 14 (2) ◽  
pp. 85-97
Author(s):  
I A OLA ◽  
O O AREMU ◽  
A A ADERINLEWO ◽  
E S.A AJISEGIRI ◽  
P O AIYEDUN ◽  
...  

Development of precision machines to handle some of the field activities involved in the cultivation of cassava is a highly welcomed project among young enterprising farmers who are keen in resolving the posterity of their wellbeing as a big time farmer. Mechanization of cassava in the tropics is grossly hampered by lack of extensive knowlegde on the behaviour, physical properties of cassava stems and parameters that have great influence on the handling of the stems during cultivation, hence the limita-tion of advancing the present semi-automatic planter to fully automated one is still a mirage in the tropics. This paper presents the flow properties of cassava cuttings that can lend it to proper handling in a metering machine. A variable inclined wood surface rig with an ejection outlet was used to study the properties of the stem. Measured cassava stem predictive parameters; diamater, lentgh,weight; angle variation on the rig; response parameters; percentage ejected, percentage sliding through, forces acting on stems were obtained. The results from the study could be used to predict acurately the exact dynamics of a given stem isolated from the bulk of stem cuttings stacked in the metering hopper. Models to predict the flow properties of the stems were obtained; further simulation of the dynamics was embarked upon using MATLAB software. A major transition zone of stem characteris-tics per pecentage sliding to ejection occurred within the range of angles of 150 -300. This might be a favourable angular zone for isolating the stems from the bulk mass while the effectively isolated stems can be metered appropriately by another mechanism in the process of developing a metering device for cassava stem cuttings.


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