BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Contr. Talk 13 - Studying slow dynamics with X-ray photon correlat ion spectroscopy DTSTART;VALUE=DATE-TIME:20181212T103000Z DTEND;VALUE=DATE-TIME:20181212T105000Z DTSTAMP;VALUE=DATE-TIME:20260523T191708Z UID:indico-contribution-94-483@lindico453.srv.lu.se DESCRIPTION:Speakers: Oier Bikondoa (ESRF-The European Synchrotron\, Greno ble\, France)\nScattering experiments based on coherent X-ray beams have o pened new possibilities for the investigation of soft and hard condensed m atter. X-ray photon correlation spectroscopy (XPCS) allows to access a wid e variety of dynamic phenomena at the nanoscale by studying the temporal c orrelations among photons that are scattered by a material when it is illu minated using a coherent X-ray beam. \nWe present two examples of XPCS stu dies on systems with slow dynamics that illustrate the capabilities of the technique in SAXS and GISAXS geometries: (a) Dynamics of ion beam eroded surfaces\, which represent a paradigmatic case of sustained non-equilibriu m dynamics governed by the complex interplay between the mechanisms that t end to roughen and smoothen the surface [1]\; (b) An ongoing study on the initial steps of self-assembly mechanism and gelation of a pH-sensitive lo w molecular weight hydrogelator\, controlling both assembly rate and morp hology of the self-assembled structures.\nWe shall also discuss on the ben efits and possibilities that the new diffraction limited storage rings bri ng about for XPCS studies.\n\nhttps://lindico453.srv.lu.se/event/67/contri butions/483/ LOCATION:Elite Hotel Ideon Tera URL:https://lindico453.srv.lu.se/event/67/contributions/483/ END:VEVENT BEGIN:VEVENT SUMMARY:Contr. Talk 12 - Effect of confinement on lyotropic lamellae dynam ics under shear flow DTSTART;VALUE=DATE-TIME:20181212T101000Z DTEND;VALUE=DATE-TIME:20181212T103000Z DTSTAMP;VALUE=DATE-TIME:20260523T191708Z UID:indico-contribution-94-482@lindico453.srv.lu.se DESCRIPTION:Speakers: Luigi Gentile (Department of Biology\, Microbial Eco logy Group\, Lund University)\nLyotropic lamellar phases under shear flow show surprising changes in the microscopic structures and physical propert ies. Lamellae-to-multi-lamellar-vesicle (MLV) transition has been widely i nvestigated\, whereas lamellae tilting and vesicles inclination have not b een highlighted during this kind of transition. Flow instabilities and the ir correlation with structures and properties in a confined gap is also ma tter of investigation. Here time-resolved flow-small angle neutron scatter ing (SANS) experiments have been carried out using a 1-2 shear cell to det ect inclination and deformation of the MLVs and to correlate spatially dis tributed structures in the Couette gap with progressive evolution of the l ocal viscosity towards two significantly different values\, leading to sta ble and periodic viscosity oscillations. The inclination angle of the MLVs has been addressed in terms of capillary number and its spatial behavior along the Couette gap in terms of gap confinement.\n\nhttps://lindico453.s rv.lu.se/event/67/contributions/482/ LOCATION:Elite Hotel Ideon Tera URL:https://lindico453.srv.lu.se/event/67/contributions/482/ END:VEVENT BEGIN:VEVENT SUMMARY:Keynote 11 - Development of µRheoSANS and Investigating the Struc ture and Rheology of Complex Fluids at High Shear Rate DTSTART;VALUE=DATE-TIME:20181212T093000Z DTEND;VALUE=DATE-TIME:20181212T101000Z DTSTAMP;VALUE=DATE-TIME:20260523T191708Z UID:indico-contribution-94-481@lindico453.srv.lu.se DESCRIPTION:Speakers: Katie Weigandt (National Inst. of Science and Techno logy Center for Neutron Research\, USA)\nWe are developing slit rheometer s compatible with simultaneous small angle neutron scattering (SANS) measu rements to directly correlate structure and rheology over a broad range of conditions. Eventually we hope to probe sample structure in Poiseuille fl ow at high shear rates\, under high pressure head\, and relatively high te mperatures. This builds upon an existing suite of Couette rheoSANS and flo wSANS devices at the NIST Center for Neutron Research that are accessible to the scientific community through a peer reviewed proposal system. Indus trial applications\, such as lubrication\, mixing\, spraying and injection \, involve the flow of complex fluids at high deformation rates. Clogging\ , fluid degradation\, and other processing challenges can arise in these e xtreme contexts and are often driven by structural changes in the fluid. T o date\, we have developed a prototype slit rheometer capable of simultane ously measuring structure and rheology of relatively low viscosity or shea r thinning fluids (η∞ < 5 mPa∙s) at shear rates up to 100\,000 s-1 an d a capillary rheoSANS instrument capable of simultaneously measuring stru cture and rheology at rates up to 106 s-1. Our initial investigations have focused on measuring wormlike micelle solutions at low to moderate shear rates and comparing the results with Couette rheoSANS measurements. In thi s talk we will discuss the ongoing development of µRheoSANS measurements including our existing low-pressure apparatus\, the capillary device and o ur newly built high pressure µRheoSANS device\, designed to withstand pre ssure drops or pressure heads up to 350 bar. This device will enable us to measure SANS at shear rates up to 106 in samples with η∞ ~ 100 mPa∙s . Furthermore\, we will discuss the results of a series of experiments aim ed at understanding the rheological response of wormlike micelle solutions at relatively high shear rates.\n\nhttps://lindico453.srv.lu.se/event/67/ contributions/481/ LOCATION:Elite Hotel Ideon Tera URL:https://lindico453.srv.lu.se/event/67/contributions/481/ END:VEVENT END:VCALENDAR