Framing in design: A formal analysis and failure modes

This contribution presents a formal description of the design practice of framing and identifies two general modes in which framing can lead to failure in design projects. The first is called the goal reformulation failure mode and occurs when designers reformulate the goal of the client in a design task and give design solutions that solve the reformulated goal but not the original goal. The second is called the frame failure mode and occurs when designers propose a frame for the design task that cannot be accepted by the client. The analysis of framing and its failure modes is aimed at better understanding this design practice and provides a first step towards arriving at criteria that successful applications of framing should meet. The description and the failure modes are illustrated by critically considering an initially successful case of framing, namely the redesign of the Kings Cross entertainment district in Sydney

Self-sufficient microfluidic systems using highly porous elastomeric sponges

Conventional microfluidic systems enable the manipulation of liquids in micro- scale structures. However, the majority of microfluidic systems rely on external off-chip equipment, such as pumps, tubes and valves for driving and control of flow. This in turn increases the overall costs, and dimensions of the system while decreases their utility for point-of-care purposes, and importantly their widespread application in biological laboratories. Chapter 1 presents a brief overview of self-sufficient microfluidic devices, and explores self-sufficient microfluidic components made of polydimethylsiloxane (PDMS) capable of storage and release of aqueous solutions into fluidic environments, which can be operated without the need for external off-chip equipment, and specialised training in microfluidics. This review identified a clear gap in the current body of knowledge and motivated me to develop PDMS sponges as a building block of self-sufficient lab-on-a-chip structures. Chapter 2 presents my first research contribution. Here, I fabricated a highly porous sponge by templating microscale droplets of water in PDMS using a microfluidic T-junction system. Scanning electron microscopy revealed the unique structure of the sponge, consisting of large pores which were only interconnected by small holes. This unique structure allowed for storage of aqueous solutions and their slow release into fluidic environments. Experiments indicated that the release characteristics of the sponge can be tuned by varying the size of the pores and interconnecting holes. I further demonstrated the capability of the highly porous PDMS sponge for the chemical stimulation of cultured cells. As a proof-of-concept, the sponge was loaded with ionomycin and placed into a well pre-coated with human umbilical vein endothelial cells. This enabled me to monitor the intracellular calcium signaling of cells in response to releasing ionomycin using a simple setup. I also demonstrated the ability of the PDMS sponge for the active release of stored chemicals into a microfluidic system. A PDMS sponge was loaded with an aqueous solution, and squeezed using a simple screw mechanism. This enabled me to release the stored solution in a controlled manner over consequent cycles into the surrounding flow. Chapter 3 presents my second research contribution. Here I demonstrated the capability of the highly porous PDMS sponge for the generation of micro- droplets of aqueous solutions in oil by simply squeezing the sponge. The small interconnecting holes located at the interface of the sponge and the surrounding oil acted as microscale orifices, enabling the generation of hundreds of droplets, with the majority of them ranging from 10 to 200 μm. I demonstrated the ability of sponge-based droplet generation for the encapsulation of cells. As a proof-of-concept, monocytic leukaemia cells were encapsulated in droplets containing cell culture medium. The density of encapsulated cells was proportional to the volume of droplets as well as the concentration of cells, enabling me to produce hundreds of isolated droplets with various cell populations. I further investigated the ability of produced droplets for studying the response of cells to chemical stimulation. As a proof-of-concept, the leukaemia cells were stimulated with hydrogen peroxide prior to encapsulation. The quick settling of encapsulated cells facilitated monitoring their responses using fluorescent microscopy. Investigation of cell viability yielded similar results compared to off-chip experiments in the absence and presence of hydrogen peroxide. Experiments indicated the ability for conducting parallel experiments using multiple isolated cell clusters simultaneously. Chapter 4 presents a summary of the key findings of this thesis. overall, the highly porous PDMS sponges developed during this research creates unprecedented opportunities for generation of self-sufficient microfluidic systems for various cellular assays

Phase Mixing of Alfvén Waves Near a 2D Magnetic Null Point

The propagation of linear Alfvén wave pulses in an inhomogeneous plasma near a 2D coronal null point is investigated. When a uniform plasma density is considered, it is seen that an initially planar Alfvén wavefront remains planar, despite the varying equilibrium Alfvén speed, and that all the wave collects at the separatrices. Thus, in the non-ideal case, these Alfvénic disturbances preferentially dissipate their energy at these locations. For a non-uniform equilibrium density, it is found that the Alfvén wavefront is significantly distorted away from the initially planar geometry, inviting the possibility of dissipation due to phase mixing. Despite this however, we conclude that for the Alfvén wave, current density accumulation and preferential heating still primarily occur at the separatrices, even when an extremely non-uniform density profile is considered

Dynamics of high viscosity contrast confluent microfluidic flows

The laminar nature of microfluidic flows is most elegantly demonstrated via the confluence of two fluids forming two stable parallel flows within a single channel meeting at a highly stable interface. However, maintenance of laminar conditions can become complicated when there is a large viscosity contrast between the neighbouring flows leading to unique instability patterns along their interface. Here, we study the dynamics of high viscosity contrast confluent flows - specifically a core flow made of highly viscous glycerol confined by sheath flows made of water within a microfluidic flow focusing system. Our experiments indicate the formation of tapered core structures along the middle of the channel. Increasing the sheath flow rate shortens the tapered core, and importantly induces local instability patterns along the interface of core-sheath flows. The dynamics of such tapered core structures is governed by the intensity of instability patterns and the length of the core, according to which the core structure can experience stable, disturbed, broken or oscillated regimes. We have studied the dynamics of tapered core structures under these regimes. In particular, we have analysed the amplitude and frequency of core displacements during the broken core and oscillating core regimes, which have not been investigated before

An automated optofluidic biosensor platform combining interferometric sensors and injection moulded microfluidics

A primary limitation preventing practical implementation of photonic biosensors within point-of-care platforms is their integration with fluidic automation subsystems. For most diagnostic applications, photonic biosensors require complex fluid handling protocols; this is especially prominent in the case of competitive immunoassays, commonly used for detection of low-concentration, low-molecular weight biomarkers. For this reason, complex automated microfluidic systems are needed to realise the full point-of-care potential of photonic biosensors. To fulfil this requirement, we propose an on-chip valve-based microfluidic automation module, capable of automating such complex fluid handling. This module is realised through application of a PDMS injection moulding fabrication technique, recently described in our previous work, which enables practical fabrication of normally closed pneumatically actuated elastomeric valves. In this work, these valves are configured to achieve multiplexed reagent addressing for an on-chip diaphragm pump, providing the sample and reagent processing capabilities required for automation of cyclic competitive immunoassays. Application of this technique simplifies fabrication and introduces the potential for mass production, bringing point-of-care integration of complex automated microfluidics into the realm of practicality. This module is integrated with a highly sensitive, label-free bimodal waveguide photonic biosensor, and is demonstrated in the context of a proof-of-concept biosensing assay, detecting the low-molecular weight antibiotic tetracycline

“There are things I want to say but you do not ask”: a comparison between standardised and individualised evaluations in substance use treatment

There has been an increasing call for service users to be more actively involved with the evaluation of treatment outcomes. One strategy to impove such involvement is to ask service users to contribute with their own criteria for evaluation by sharing their personal story and perspective about their clinical situation. In this cross-sectional study, we contrasted the contents elicited by service users completing two individualised measures against the contents of three widely used standardised measures. We also compared two methods to generate individualised data using self-report and interview-based instruments (PSYCHLOPS and PQ). Following a thematic comparison approach, we found that one quarter of the problems reported by patients in individualised measures were not covered by any of our standardised comparators. Also, half of our sample generated at least one problem whose theme was not covered by any of the three standardised measures. We also found that patients in this population have many other concerns beyond drug use. These included psychological (e.g. interpersonal relationships) and socio-economic (e.g. money) problems, which were frequently reported. Our study suggests that listening to service users’ stories allows us to capture issues of importance to service users in substance use treatment, which may be underestimated by standardised measures

An Examination of Children’s Learning Progression Shifts While Using Touch Screen Virtual Manipulative Mathematics Apps

The purpose of this study was to examine shifts in young children\u27s learning progression levels while they interacted with virtual manipulative mathematics apps on touch-screen devices. A total of 100 children participated in six mathematics learning sequences while using 18 virtual manipulative mathematics touch-screen apps during clinical interviews. Researchers developed a micro-scoring tool to analyze video data from two camera sources (i.e., GoPro camera, wall-mounted camera). Our results showed that it is possible to document evidence of shifts in children\u27s learning progressions while they are interacting with mathematics apps on touch-screen devices. Our results also indicated patterns in the children\u27s interactions that were related to the shifts in their learning progression levels. These results suggest that an open-ended number of tasks with a variety of representations and tasks at varying levels of difficulty led to children refining their understanding and shaping their concept image of mathematical ideas resulting in incremental shifts in learning. The results of this study have important implications about how mathematical tasks in touch-screen apps may prompt children\u27s incremental learning progression shifts to occur, and thereby promote opportunities for learning. We propose that design features in mathematics apps can be created to support and encourage these learning shifts

Review of small rural health services in Victoria: how does the nursing-medical division of labour affect access to emergency care?

Aims This paper is based on a review of the Australian and International literature relating to the nursing-medical division of labour. It also explores how the division of labour affects patient access to emergency care in small rural health services in Victoria, Australia. Background The paper describes the future Australian health workforce and the implications for rural Victoria. The concept of division of labour and how it relates to nursing and medicine is critically reviewed. Two forms of division of labour emerge – traditional and negotiated division of labour. Key themes are drawn from the literature that describes the impact of a traditional form of division of labour in a rural context. Methods This paper is based on a review of the Australian and international literature, including grey literature, on the subject of rural emergency services, professional boundaries and roles, division of labour, professional relationships and power and the Australian health workforce. Results In Australia, the contracting workforce means that traditional divisions of labour between health professionals cannot be sustained without reducing access to emergency care in rural Victoria. A traditional division of labour results in rural health services that are vulnerable to slight shifts in the medical workforce, unsafe services and recruitment and retention problems. A negotiated form of division of labour provides a practical alternative. Conclusion A division of labour that is negotiated between doctors and nurses and supported by a legal and clinical governance framework, is needed to support rural emergency services. The published evidence suggests that this situation currently does not exist in Victoria. Strategies are offered for creating and supporting a negotiated division of labour

Forward modeling of standing kink modes in coronal loops. I. Synthetic views

Kink magnetohydrodynamic (MHD) waves are frequently observed in various magnetic structures of the solar atmosphere. They may contribute significantly to coronal heating and could be used as a tool to diagnose the solar plasma. In this study, we synthesize the Fe ix λ171.073 emission of a coronal loop supporting a standing kink MHD mode. The kink MHD wave solution of a plasma cylinder is mapped into a semi-torus structure to simulate a curved coronal loop. We decompose the solution into a quasi-rigid kink motion and a quadrupole term, which dominate the plasma inside and outside of the flux tube, respectively. At the loop edges, the line of sight integrates relatively more ambient plasma, and the background emission becomes significant. The plasma motion associated with the quadrupole term causes spectral line broadening and emission suppression. The periodic intensity suppression will modulate the integrated intensity and the effective loop width, which both exhibit oscillatory variations at half of the kink period. The quadrupole term can be directly observed as a pendular motion at the front view

Three-Wall Segment (TriSeg) Model Describing Mechanics and Hemodynamics of Ventricular Interaction

A mathematical model (TriSeg model) of ventricular mechanics incorporating mechanical interaction of the left and right ventricular free walls and the interventricular septum is presented. Global left and right ventricular pump mechanics were related to representative myofiber mechanics in the three ventricular walls, satisfying the principle of conservation of energy. The walls were mechanically coupled satisfying tensile force equilibrium in the junction. Wall sizes and masses were rendered by adaptation to normalize mechanical myofiber load to physiological standard levels. The TriSeg model was implemented in the previously published lumped closed-loop CircAdapt model of heart and circulation. Simulation results of cardiac mechanics and hemodynamics during normal ventricular loading, acute pulmonary hypertension, and chronic pulmonary hypertension (including load adaptation) agreed with clinical data as obtained in healthy volunteers and pulmonary hypertension patients. In chronic pulmonary hypertension, the model predicted right ventricular free wall hypertrophy, increased systolic pulmonary flow acceleration, and increased right ventricular isovolumic contraction and relaxation times. Furthermore, septal curvature decreased linearly with its transmural pressure difference. In conclusion, the TriSeg model enables realistic simulation of ventricular mechanics including interaction between left and right ventricular pump mechanics, dynamics of septal geometry, and myofiber mechanics in the three ventricular walls