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The influence of a treatment process on the reaction to water of durable and water resistant wood/plastic composites

Hosseinihashemi S. K., Badritala A.

Drewno : prace naukowe, doniesienia, komunikaty

2017

vol. 60, nr 200

21--34

In this study, the effect of the treatment process on the decay resistance and water absorption behaviour of wood flour/polypropylene composites was investigated. Composites based on ZB-pretreated, ZB-treated-during-manufacturing, and untreated wood flour, polypropylene were exposed to the decay by the white-rot fungus (Trametes versicolor) for 14 weeks. The long-term water absorptions of samples were evaluated by immersing them in water at room temperature for several weeks, and water diffusion coefficients (WDC) were also calculated by evaluating the water absorption isotherms. The morphology of the composites was characterized using scanning electron microscopy (SEM). The results showed that the composite made with ZB-treated wood flour exhibited the same water absorption as the control composite; while the ZB-pretreated wood flour, produced the highest improvements in water absorption performance. The water absorption of WPCs increased after exposure to white- rot fungus, where the water absorption of the decayed UT-WPC, ZB-T-WPC, and ZB-PT-WPC specimens increased by 41.4%, 43.25%, and 36.7%, respectively compared to the undecayed UT-WPC, ZB-T-WPC, and ZB-PT-WPC specimens. The undecayed ZB- -treated sample and decayed ZB-pretreated composite exhibited the lowest and highest WDCs, respectively. The SEM micrographs revealed that the outer surface of the wood fibers were coated by some crystalline deposits of zinc borate. Much larger WDC values are observed from the ZB-pretreated and decayed composites when compared to the ZB-treated, control, and undecayed composites. The results of this study help to clarify the effect of T. versicolor on the dynamic moisture absorption process of WPCs impregnated with ZB.

Process monitoring and closed loop controlled process

Neugebauer R., Bräunlich H., Scheffler S.

Archives of Civil and Mechanical Engineering

2009

Vol. 9, no 2

105-126

There are a number of variables which can seriously affect the sheet metal forming process. By determining the process fluctuations, it will ultimately be possible to improve the production process. To do this, monitored or closed loop controlled processes potentially constitute an important tool for the reduction of defects, reduction of rework and a better quality of final products. The Fraunhofer Institute for Machine Tools and Forming Technology (IWU) in Chemnitz investigated typical process variables such as flange movement as the basis for control systems. Different kinds of non-contact sensors were successfully tested. A multi-point cushion or tool integrated piezo-elements in conjunction with torsion-elastic tools were used as reacting systems. One application used process monitoring with one or more sensors to support quality control, or the same system with an add-on for early error recognition and automatic recommendation of corrective measures. Finally, fully controlled loop systems based on intelligent algorithms were developed.

Istnieje pewna liczba czynników, które mogą poważnie wpłynąć na proces kształtowania blach. Poprzez określenie zmienności procesu staje się możliwe poprawienie procesu produkcji. W tym celu monitorowanie lub sterownie procesami poprzez sprzężenie zwrotne stanowi ważne narzędzie pozwalające na redukcję wad, zmniejszenie ilości poprawek i lepszą jakość końcowych produktów. Fraunhofer Institute for Machine Tools and Forming Technology (IWU) w Chemnitz zbadał typowe zmienne procesu, takie jak np. przemieszczenie kołnierza jako podstawę dla systemów kontroli. Różne rodzaje bezkontaktowych sensorów zostały z powodzeniem przetestowane. Wielopunktowa poduszka lub zintegrowane piezoelementy w połączeniu z narzędziami skrętno-sprężystymi zostały użyte jako systemy reagujące. Kompletny system kontroli opartym na inteligentnych algorytmach został opracowany.