Colloidal Particles at Chiral Liquid Crystal Interfaces

Colloidal particles trapped at an interface between two fluids can form a wide range of different structures. Replacing one of the fluid with a liquid crystal increases the complexity of interactions and results in a greater range of possible structures. New behaviour emerges when colloidal particles interact with defects in the liquid crystal phases. Here we discuss the templating of colloids at a cholesteric isotropic interface.Comment: 7 pages, 5 figure

An investigation into the use of a blended model of learning

The weaknesses of ‗traditional‘ modes of instruction in accounting education have been widely discussed. Many contend that the traditional approach limits the ability to provide opportunities for students to raise their competency level and allow them to apply knowledge and skills in professional problem solving situations. However, the recent body of literature suggests that accounting educators are indeed actively experimenting with ‗non-traditional‘ and ‗innovative‘ instructional approaches, where some authors clearly favour one approach over another. But can one instructional approach alone meet the necessary conditions for different learning objectives? Taking into account the ever changing landscape of not only business environments, but also the higher education sector, the premise guiding the collaborators in this research is that it is perhaps counter productive to promote competing dichotomous views of ‗traditional‘ and ‗non-traditional‘ instructional approaches to accounting education, and that the notion of ‗blended learning‘ might provide a useful framework to enhance the learning and teaching of accounting. This paper reports on the first cycle of a longitudinal study, which explores the possibility of using blended learning in first year accounting at one campus of a large regional university. The critical elements of blended learning which emerged in the study are discussed and, consistent with the design-based research framework, the paper also identifies key design modifications for successive cycles of the research

Multidisciplinary methodology for turbine overspeed analysis

In this paper, an integrated approach to turbine overspeed analysis is presented, taking into account the secondary air system dynamics and mechanical friction in a turbine assembly following an unlocated high-pressure shaft failure. The axial load acting on the rotating turbine assembly is a governing parameter in terms of overspeed protection since it governs the level of mechanical friction which acts against the turbine acceleration due to gas torque. The axial load is dependent on both the force coming from secondary air system cavities surrounding the disc and the force on the rotor blades. It is highly affected by secondary air system dynamics because rotor movement modifies the geometry of seals and flow paths within the network. As a result, the primary parameters of interest in this study are the axial load on the turbine rotor, the friction torque between rotating and static structures and the axial position of the rotor. Following an initial review of potential damage scenarios, several cases are run to establish the effect of each damage scenario and variable parameter within the model, with comparisons being made to a baseline case in which no interactions are modelled. This allows important aspects of the secondary air system to be identified in terms of overspeed prevention, as well as guidelines on design changes in current and future networks that will be beneficial for overspeed prevention

Colloidal templating at a cholesteric - oil interface: Assembly guided by an array of disclination lines

We simulate colloids (radius $R \sim 1\mu$m) trapped at the interface between a cholesteric liquid crystal and an immiscible oil, at which the helical order (pitch p) in the bulk conflicts with the orientation induced at the interface, stabilizing an ordered array of disclinations. For weak anchoring strength W of the director field at the colloidal surface, this creates a template, favoring particle positions eitheron top of or midway between defect lines, depending on $\alpha = R/p$. For small $\alpha$, optical microscopy experiments confirm this picture, but for larger $\alpha$ no templating is seen. This may stem from the emergence at moderate W of a rugged energy landscape associated with defect reconnections.Comment: 5 pages, 4 figure

Life Satisfaction and Maslow\u27s Hierarchy of Needs: An Analysis of 48 Nations

To assess whether Maslow\u27s hierarchy of needs can predict life satisfaction, the present study utilizes Wave 7 (2017-2020) of the World Values Survey. These data include questions on health and financial satisfaction, as well as trust and confidence in societal institutions disseminated to over 69 000 individuals from 48 countries. According to Maslow\u27s hierarchy of needs, it is predicted that greater life satisfaction will be subsequently predicted by health satisfaction at the first level, financial satisfaction at the second level, and trust and confidence at the third level. Data were split by both the individual and national levels to determine how life satisfaction can be predicted by individuals and nations. Based on previous findings from Wave 6 (2010-2014), we anticipate that financial satisfaction and income (aligning with Maslow\u27s second level) are more important predictors of greater life satisfaction than health satisfaction (aligning with Maslow\u27s first level). Results will provide important implications regarding the application of Maslow\u27s hierarchy of needs at both the individual and national levels

Colloids at liquid crystal interfaces

This thesis presents a study of colloidal particles dispersed in thermotropic liquid crystals. It has a specific focus on colloids in the presence of an interface between the liquid crystal and an isotropic fluid. Three systems are studied: colloids trapped at a planar interface between a cholesteric liquid crystal (CLC) and an isotropic oil, nematic emulsions with interfacial colloids and the influence of colloids on the phase transition kinetics of the cholesteric blue phase. Experiments are carried out using polarising optical and confocal microscopy. By combining these techniques, the director field of the liquid crystals could be imaged in combination with precise observation of the colloid locations. Custom image analysis algorithms are developed to extract the information. In the first system, we create an interface between a cholesteric liquid crystal and an isotropic liquid. Homeotropic anchoring leads to a well aligned cholesteric layer and the formation of the fingerprint texture. Fluorescent colloidal particles with planar surface anchoring are dispersed in the CLC. A majority of these particles decorate the interface. The final distribution of particles perpendicular to the interface has a clear dependence on the particle size. In the plane of the interface, surface defects form a template for the colloids. The second system is a particle dispersion within a short pitch CLC which exhibits a blue phase. The colloidal particles and associated defects act as nucleation sites for the blue phase in the cholesteric to blue phase transition. Colloidal particles cause localised melting from the blue phase to the isotropic phase and lead to a larger temperature range for coexistence between isotropic and blue phases. Furthermore, the isotropic regions can be faceted, their shape and size is controlled by the blue phase elasticity. In the final system, a nematic emulsion is created. Droplets of nematic LC are dispersed in water. Colloidal particles initially mixed into the liquid crystal decorate the interface between the two fluids. The addition of a surfactant switches the liquid crystal alignment at the fluid-fluid interface from planar to homeotropic. This forces a change in defect structure, from two boojums at the poles to a hedgehog defect in the droplet centre. The presence of colloids affects the switching dynamics and alters the final liquid crystal alignment preventing the droplets from forming a central radial defect. There is a symbiotic relationship between the particle properties - size and anchoring at the surface - and the elastic properties of the liquid crystal in the bulk and in the presence of an interface with an isotropic fluid. How the systems respond when the balance of these factors is altered is explored throughout the thesis

Three-dimensional through-flow modelling of axial flow compressor rotating stall and surge

This paper presents a three-dimensional through-flow approach based on the cylindrical Euler equations incorporating a body force method. Blade performance is captured through a mixture of empirical correlations and a novel reverse flow treatment. The code is the first application of a physically correct Godunov solver to three-dimensional rotating stall and surge modelling. This solver ensures the accurate calculation of inter-cell fluxes unlike in typical modern CFD codes in which the non-linear convective terms are linearised. Validation consists of modelling a low speed three-stage axial compressor in all operating regions, recreating the reverse flow, rotating stall and forward flow characteristics with good agreement to experimental data. Additional comparisons are made against rotating stall cell size and speed, to which good agreement is also shown. The paper ends with some full surge cycle simulations modifying both the tank volume after the compressor and the level of inlet distortion applied. Both tank volume and level of distortion have been found to affect the type of instability developed. The development of this code is a step forward in compressor rotating stall and reverse flow modelling and allows recreation of a full compressor map at a significantly low computational cost when compared to commercially available 3D CFD codes

Stakeholder perspectives on implementing accreditation programs: A qualitative study of enabling factors

Background: Accreditation programs are complex, system-wide quality and safety interventions. Despite their international popularity, evidence of their effectiveness is weak and contradictory. This may be due to variable implementation in different contexts. However, there is limited research that informs implementation strategies. We aimed to advance knowledge in this area by identifying factors that enable effective implementation of accreditation programs across different healthcare settings. Methods. We conducted 39 focus groups and eight interviews between 2011 and 2012, involving 258 diverse healthcare stakeholders from every Australian State and Territory. Interviews were semi-structured and focused on the aims, implementation and consequences of three prominent accreditation programs in the aged, primary and acute care sectors. Data were thematically analysed to distil and categorise facilitators of effective implementation. Results: Four factors were identified as critical enablers of effective implementation: the accreditation program is collaborative, valid and uses relevant standards; accreditation is favourably received by health professionals; healthcare organisations are capable of embracing accreditation; and accreditation is appropriately aligned with other regulatory initiatives and supported by relevant incentives. Conclusions: Strategic implementation of accreditation programs should target the four factors emerging from this study, which may increase the likelihood of accreditation being implemented successfully. © 2013 Hinchcliff et al.; licensee BioMed Central Ltd