Savojna svojstva lameliranog drva izrađenoga od topolovine i GFRP-a

In this study, 4 layers of 5 mm thick slats obtained by sawing method from poplar wood were used. Plain woven GRFP with low density and grammage of 100 g/m2 (Type 1) and plain woven GRFP with high density and grammage of 200 g/m2 (Type 2) were placed and glued between each layer. Polyvinyl acetate (PVAc-D4), Polyurethane (PU) and dual-component Epoxy (L285-resin and H285-hardener) adhesives were used for gluing the layers. Strength values (bending and modulus of elasticity) between the obtained layers were investigated. As a result of the study, it was determined that epoxy glue has higher strength than polyurethane and polyvinyl acetate glues; Type 2 plain woven fabric has higher strength than Type 1 plain woven fabric; and parallel load to the glue line results in higher performance than perpendicular load to the glue line.U radu se prikazuje istraživanje lameliranog drva izrađenoga od piljenjem proizvedenih topolovih platica debljine 5 mm složenih u četiri sloja. Između svakog sloja zalijepljena je plošno tkana GRFP tkanina male gustoće i površinske mase 100 g/m2 (tip 1) i plošno tkana GRFP tkanina velike gustoće i površinske mase 200 g/m2 (tip 2). Za lijepljenje drva i tkanine upotrijebljena su ova ljepila: polivinilacetatno (PVAc-D4), poliuretansko (PU) i dvokomponentno epoksidno (L285-mola i H285-otvrdnjivač). Istražene su vrijednosti čvrstoće (savijanje i modul elastičnosti) te je utvrđeno da epoksidno ljepilo ima veću čvrstoću nego poliuretansko i polivinilacetatno ljepilo. Nadalje, tkanina tipa 2 ima veću čvrstoću od tkanine tipa 1, a djelovanjem sile paralelno sa sljubnicom dobivena su bolja svojstva nego pri djelovanju sile okomito na sljubnicu

Dynamical Principles of Emotion-Cognition Interaction: Mathematical Images of Mental Disorders

The key contribution of this work is to introduce a mathematical framework to understand self-organized dynamics in the brain that can explain certain aspects of itinerant behavior. Specifically, we introduce a model based upon the coupling of generalized Lotka-Volterra systems. This coupling is based upon competition for common resources. The system can be regarded as a normal or canonical form for any distributed system that shows self-organized dynamics that entail winnerless competition. Crucially, we will show that some of the fundamental instabilities that arise in these coupled systems are remarkably similar to endogenous activity seen in the brain (using EEG and fMRI). Furthermore, by changing a small subset of the system's parameters we can produce bifurcations and metastable sequential dynamics changing, which bear a remarkable similarity to pathological brain states seen in psychiatry. In what follows, we will consider the coupling of two macroscopic modes of brain activity, which, in a purely descriptive fashion, we will label as cognitive and emotional modes. Our aim is to examine the dynamical structures that emerge when coupling these two modes and relate them tentatively to brain activity in normal and non-normal states

Determination of Critical Width of Multiple Delamination in Laminated Composite Plate Under Buckling Load

In order to investigate the effects of multiple delaminations' width on the buckling loads of the simply supported woven steel-reinforced thermoplastic-laminated composite plates, having the strip and lateral delamination regions between each layers, 3-D finite elements models have been established. The critical delamination representing the maximum delamination sizes and tolerate value in a structure without decreasing compressive strength has been obtained from the evalution of the buckling analyses. There are four layers and two different delamination shapes, vertical and horizontal, in models. The orientation angles of the fibers have been choosen as [0 degrees](4), [15 degrees/-15 degrees](s), [15 degrees/-15 degrees](2), [30 degrees/-308](s), [30 degrees/-30 degrees](2), [45 degrees](4) and [45 degrees/-45 degrees](s). Firstly, the harmony between theoretical and finite element solutions' results of the plate without delamination has been shown. Then, the buckling loads have been determined for each model having different delamination width. There is no important decrease in buckling loads until certain values of delamination width exactly. For the symmetrical and antisymmetrical cases the obtained results show that the changing ratios are the same for each angle. By comparing orientation angle, it can be said that the values and changing ratios of the buckling loads of high-value orientation angles are higher than the low values