Articulating current service development practices: a qualitative analysis of eleven mental health projects.

BACKGROUND: The utilisation of good design practices in the development of complex health services is essential to improving quality. Healthcare organisations, however, are often seriously out of step with modern design thinking and practice. As a starting point to encourage the uptake of good design practices, it is important to understand the context of their intended use. This study aims to do that by articulating current health service development practices. METHODS: Eleven service development projects carried out in a large mental health service were investigated through in-depth interviews with six operation managers. The critical decision method in conjunction with diagrammatic elicitation was used to capture descriptions of these projects. Stage-gate design models were then formed to visually articulate, classify and characterise different service development practices. RESULTS: Projects were grouped into three categories according to design process patterns: new service introduction and service integration; service improvement; service closure. Three common design stages: problem exploration, idea generation and solution evaluation - were then compared across the design process patterns. Consistent across projects were a top-down, policy-driven approach to exploration, underexploited idea generation and implementation-based evaluation. CONCLUSIONS: This study provides insight into where and how good design practices can contribute to the improvement of current service development practices. Specifically, the following suggestions for future service development practices are made: genuine user needs analysis for exploration; divergent thinking and innovative culture for idea generation; and fail-safe evaluation prior to implementation. Better training for managers through partnership working with design experts and researchers could be beneficial.

DC current rectification using indium-gallium zinc oxide-based selfswitching diodes

Self-switching diodes have been fabricated within a single layer of indium-gallium zinc oxide (IGZO). Current-voltage (I-V) measurements show the nanometer-scale asymmetric device gave a diode-like response. Full current rectification was achieved using very narrow channel widths of 50nm, with a turn-on voltage, Von, of 2.2V. The device did not breakdown within the -10V bias range measured. This single diode produced a current of 0.1μA at 10V and a reverse current of less than 0.1nA at -10V. Also by adjusting the channel width for these devices, Von could be altered; however, the effectiveness of the rectification also changed. © 2013 IEEE.

Current research in embankment dam engineering at imperial college London

This paper gives a short introduction to two research streams in embankment dam engineering underway at Imperial College London. The first is the modelling of embankment dam behaviour during earthquakes and the second is an investigation into the susceptibility of granular filters to internal erosion. The research motivation, methods and expected outcomes of each stream are discussed.

Plasmonic silver nanoparticles for improved organic solar cells

In the present work we compare the performance of organic solar cells, based on the bulk heterojunction system of P3HT:PCBM when adequate silver nanoparticles (NPs) are incorporated in two distinct places among the device structure. Introduction of NPs on top of the transparent anode revealed better overall performance with an increased efficiency of 17%. Alternatively, placing the NPs on top of the active photovoltaic layer resulted to 25% higher photo-current generation albeit with inferior electrical characteristics (i.e series and shunt resistance). Our findings suggest that enhanced scattering to non-specular directions from NPs site is maximized when penetrating light meets the particles after the polymer blend, but even this mechanism is not sufficient enough to explain the enhanced short circuit current observed. A second mechanism should be feasible; that is plasmon enhancement which is more efficient in the case where NPs are in direct contact with the polymer blend. J-V characteristics measured in the dark showed that NPs placed on top of the ITO film act as enhanced hole conducting sites, as evident by the lower series resistance values in these cells, suggesting this mechanism as more significant in this case. © 2012 Elsevier B.V. All rights reserved.

Modeling current-voltage behaviour in oxide TFTs combining trap-limited conduction with percolation

Current-voltage behaviour of oxide TFTs is modeled based on trap-limited conduction and percolation theories. The mobility has a power-law dependence, in which percolation controls the exponent while trap states determine constant term in the power law. The proposed model, which is fully physically-based, provides a good agreement with measured transistor characteristics as well as transient operations of fabricated pixel test circuits for oxide-based OLED displays. © 2013 Society for Information Display.

Performance of hybrid buffer Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) layers doped with plasmonic silver nanoparticles

We compare the performance of a typical hole transport layer for organic photovoltaics (OPVs), Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) thin film with a series of PEDOT:PSS layers doped with silver (Ag) nanoparticles (NPs) of various size distributions. These hybrid layers have attracted great attention as buffer layers in plasmonic OPVs, although there is no report up to date on their isolated performance. In the present study we prepared a series of PEDOT:PSS layers sandwiched between indium tin oxide (ITO) and gold (Au) electrodes. Ag NPs were deposited on top of the ITO by electron beam evaporation followed by spin coating of PEDOT:PSS. Electrical characterization performed in the dark showed linear resistive behavior for all the samples; lower resistance was observed for the hybrid ones. It was found that the resistivity of the samples decreases with increasing the particle's size. A substantial increase of the electric field between the ITO and the Au electrodes was seen through the formation of current paths through the Ag NPs. A striking observation is the slight increase in the slope of the current density versus voltage curves when measured under illumination for the case of the plasmonic layers, indicating that changes in the electric field in the vicinity of the NP due to plasmonic excitation is a non-vanishing factor. © 2014 Published by Elsevier B.V. All rights reserved.

Parameters influencing the maximum controllable current in gate commutated thyristors

The model of interconnected numerical device segments can give a prediction on the dynamic performance of large area full wafer devices such as the Gate Commutated Thyristors (GCTs) and can be used as an optimisation tool for designing GCTs. In this study the authors evaluate the relative importance of the shallow p-base thickness, its peak concentration, the depth of the p-base and the buffer peak concentration. © The Institution of Engineering and Technology 2014.