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The wall collapse-initiated disaster in infilled reinforced concrete (RC) frame structures has been increasingly concerned by research community recently. This paper studies the seismic performances of a bare RC frame and three RC frames infilled by different lightweight materials in full scale under cyclic loads, including hollow bricks, gypsum blocks, and autoclaved lightweight concrete panels. The main studied performances include lateral resistance capacity, stiffness, wall damage, ductility, and energy dissipation capacity of the frames. Based on the experimental results and literature research, this paper discusses ideal infill materials for RC frame structures and skeleton curve of the frames. [ABSTRACT FROM AUTHOR]

Projected climate change scenarios such as frequently occurring dry summer spells are an enormous threat to the health of boreal conifer forests. We identified visible features indicating wood with tracheids predisposed for hydraulic and mechanical dysfunction in Norway spruce, suggest why this is formed during severe summer drought and hypothesised on mechanism that would cause tracheid collapse and stem cracks. Trees from southern Sweden that showed signs of severe reaction to drought, i.e. stem cracks along the trunk, were compared to healthy, undamaged trees. Rings investigated included those formed in 2006, a year with an extremely dry summer season in the study region. In southern Norway, we investigated trees with and without drought-induced top dieback symptoms. We analysed anatomical features such as tracheid lumen diameter, thickness of cell wall and its various layers (S1, S2 and S3), applied Raman imaging in order to get information on the lignin distribution in the cell wall and the compound middle lamellae and performed hydraulic flow and shrinkage experiments. Although tracheids in annual rings with signs of collapse had higher tangential lumen diameters than those in “normal” annual rings, we conclude that collapse of tracheid walls depends mainly on wall thickness, which is genetically determined to a large extent. Spruce trees that produce earlywood with extremely thin cell walls can develop wall collapse and internal cracks under the impact of dry spells. We also present a new diagnostic tool for detecting individuals that are prone to cell wall collapse and stem cracks: Lucid bands, i.e. bands in the fresh sapwood with very thin cell walls and inhomogeneous lignin distribution in the S-layers and the compound middle lamellae that lost their hydraulic function due to periods of severe summer drought. The detection of genotypes with lucid bands could be useful for an early selection against individuals that are prone to stem cracks under the impact of severe summer drought, and also for early downgrading of logs prone to cracking during industrial kiln drying. [ABSTRACT FROM AUTHOR]

Volcanic gullies develop U-shape cross-profiles due to the lahars that shape them after eruptive events. Over time, the processes of sediment-transfer change and the erosion of sub-vertical walls become a leading process. It results in debris-cones at their foot. However, the processes that generate these landforms is still unclear. Indeed, the surface is the one of a cone or a "steep debris-fan", but are these diffusive landforms starting through progressive regressive-erosion of the wall, or do they follow an original collapse? This we do not know, and as the material is poorly-sorted with a mixture of unconsolidated fine sands to large clasts, digging a trench is not possible as it destroys the material structure. Therefore, the present contribution aims to define the development mechanisms of the side-wall debris-cones using Ground Penetrating Radar imaging, working in the Tansandani Gully at Unzen Volcano (Japan). The GPR used in the study is a Mala Ramac Pro-Ex mounted with a 500 MHz shielded antenna. The GPR signal penetrated up to 4–5 m depth and the velocity was homogeneous on average through the different material layers and at the different location, although at depth variations occurred. The structure of the units in the radargrams present units' parallel to the surface for the first 40 to 60 cm, with underneath the presence of more irregular prograding units, with eventually underneath a set of units that are structureless and often rich in blocks. The two lower structureless-units are not always present and one of the debris-cone only showed a set of rough subparallel units. This differences are the result of the debris-cones being generated by (1) at first a wall collapse or by rapid water-borne processes creating (2) bulk prograding units, which have to be put in place during a heavy-rainfall event. Finally, near the surface, the (3) thin subparallel units are most probably post-rainfall deposition, resulting from gravity process in dry-material. This can be inferred because there is no evidence of erosion or remobilization in layers and the process has been observed in the field. For the observed debris-cones, their formation is dominated by a wall collapse, which is then recovered by finer-grained units deposited sub-horizontally to the surface. • GPR revealed the internal architecture of temporary wall-collapse debris-cones. • Explain Unzen gully wall long term erosion process: collapse and diffusive erosion. • The internal structure allows the identification of the otherwise unknown processes of the side-wall cones. [ABSTRACT FROM AUTHOR]

Arterial stenoses may cause critical blood flow and wall conditions leading to clinical complications. In this paper computational models of stenotic carotid arteries are proposed and the vessel wall collapse phenomenon is studied. The models are based on fluid-structure interactions (FSI) between blood and the arterial walls. Coupled finite element and computational fluid dynamics methods are used to simultaneously solve for stress and displacement in the solid, and for pressure, velocity and shear stress in the fluid domain. Results show high wall shear stress at the stenosis throat and low (negative) values accompanied by disturbed flow patterns downstream of the stenosis. The wall circumferential stress varies abruptly from tensile to compressive along the stenosis with high stress concentration on the plaque shoulders showing regions of possible plaque rupture. Wall compression and collapse are observed for severe cases. Post-stenotic collapse of the arterial wall occurs for stenotic severity as low as 50%, with the assumption that a given amount of blood flow needs to pass the stenotic artery; whereas if constant pressure drop should be maintained across a constriction, then collapse happens at severity of 75% and above. The former assumption is based on the requirement of adequate blood supply to the downstream organs/tissue, while the latter stems from the fact that the pumping mechanism of the body has a limited capacity in regulating blood pressure, in case a stenosis appears in the vasculature. [ABSTRACT FROM AUTHOR]

Isolated nematocysts of the Scyphozoan Pelagia noctiluca became diaphanous when incubated at low pH for 1 h or left at room temperature for a few hours. Diaphanous nematocysts were unable to undergo discharge when triggered by proper physico-chemical stimuli. The aim of the present study was to investigate the relationship between the morphological features of diaphanous nematocysts and the haemolytic power of their crude venom, obtained by sonication on ice. Nematocysts stored at-20 ° C in neutral medium were used as a control. Our results show that the haemolytic power of crude venom from isolated nematocysts kept at low pH or at room temperature decreased significantly with respect to the control. From this study, it can be deduced that a neutral pH and low temperature conditions are recommended to store nematocysts properly in order to use them in toxicological investigations. [ABSTRACT FROM AUTHOR]