The Effect of Convection on Disorder in Primary Cellular and Dendritic Arrays

Directional solidification studies have been carried out to characterize the spatial disorder in the arrays of cells and dendrites. Different factors that cause array disorder are investigated experimentally and analyzed numerically. In addition to the disorder resulting from the fundamental selection of a range of primary spacings under given experimental conditions, a significant variation in primary spacings is shown to occur in bulk samples due to convection effects, especially at low growth velocities. The effect of convection on array disorder is examined through directional solidification studies in two different alloy systems, Pb-Sn and Al-Cu. A detailed analysis of the spacing distribution is carried out, which shows that the disorder in the spacing distribution is greater in the Al-Cu system than in Pb-Sn system. Numerical models are developed which show that fluid motion can occur in both these systems due to the negative axial density gradient or due the radial temperature gradient which is always present in Bridgman growth. The modes of convection have been found to be significantly different in these systems, due to the solute being heavier than the solvent in the Al-Cu system and lighter than it in the Pb-Sn system. The results of the model have been shown to explain experimental observations of higher disorder and greater solute segregation in a weakly convective Al-Cu system than those in a highly convective Pb-Sn system

Fire safety science: past, present and future

Peer reviewed: NoNRC publication: Ye

Smoke control systems: design tools and best practices

NRC publication: Ye

Fire safety science: past, present and future

Peer reviewed: NoNRC publication: Ye

Ultrasound as the only nerve localization technique for peripheral nerve block.

Contains fulltext : 52686.pdf (publisher's version ) (Closed access)Ultrasound facilitates the performance of peripheral nerve blocks and may increase block quality parameters. In this report, we show that ultrasonographic guidance makes peripheral nerve blocks possible in patients in whom the traditional methods of nerve localization are limited. Four cases are described in which conventional end points for successful blocks would have been impossible to use, whereas ultrasound guidance was successful and safe. The latter method increases applicability in a larger group of patients

Shigella flexneri targets human colonic goblet cells by O antigen binding to Sialyl-Tn and Tn antigens via glycan-glycan interactions

Shigella flexneri targets colonic cells in humans to initiate invasive infection processes that lead to dysentery, and direct interactions between their lipopolysaccharide O antigens and blood group A related glycans are involved in the cell adherence interactions. Here, we show that treatment with Tn and sialyl-Tn glycans, monoclonal antibodies and lectins reactive to Tn/sialyl-Tn, and luteolin (a Tn antigen synthesis inhibitor) all significantly inhibited S. flexneri adherence and invasion of cells in vitro. Surface plasmon resonance analysis showed that lipopolysaccharide O antigen had a high affinity interaction with Tn/sialyl-Tn. Immunofluorescence probing of human colon tissue with antibodies detected expression of Tn/sialyl-Tn by MUC2 producing goblet cells (GCs), and S. flexneri incubated with human colon tissue colocalized with GCs. Our findings demonstrate that S. flexneri targets GCs in the human colonic crypts via glycan-glycan interactions, establishing new insight into the infection process in humans.Elizabeth Ngoc Hoa Tran, Christopher J. Day, Erin McCartney, Jessica Poole, Edmund Tse, Michael P. Jennings, and Renato Moron

Issues involved with thermoactive geotechnical systems: characterization of thermomechanical soil behavior and soil-structure interface behaviour

This paper focuses on the main issues discussed during a session on the impact of thermohydromechanical behavior of soils on thermoactive geotechnical systems, and how they could affect the performance of thermoactive geotechnical systems. Both soil behavior as well as soil–structure interaction behavior was discussed. The main observation from the session was that the thermohydromechanical behavior of saturated soils has reached a mature understanding, with several established constitutive models that can be used by engineers. However, there are still opportunities to enhance these constitutive models by considering issues such as unsaturated conditions, anisotropic stress states, cyclic heating and cooling effects, and changes in the preconsolidation stress during heating and cooling. Further there are still opportunities to improve our understanding of soil/concrete interface behavior, including the development of novel testing approaches

Study while you work Vocational courses in further education for 16-19 year old employees

Part funded by a research grant from the Northern Ireland Panel of SSRCSIGLEAvailable from British Library Document Supply Centre- DSC:7099.194(31) / BLDSC - British Library Document Supply CentreGBUnited Kingdo