407 research outputs found
Legal advice bureaux and the legal profession : maintaining collegiate control : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Sociology at Massey University
Legal Advice Bureaux appear to minimise the traditional professional-client relationship in which the professional establishes his or her ascendancy over the client. The present study investigates whether Legal Advice Bureaux are, therefore, weakening the New Zealand legal profession's control over its occupational domain. It is based on T.J. Johnson's "radical" theory of the professions and rejects both "conventional" and "reactionary" explanations of professions and professionalism. Following this perspective, it is proposed that Legal Advice Bureaux and those who work in them are nevertheless engaged in establishing the legal profession's occupational dominance. An inquiry into the structure, processes and ideology of Legal Advice Bureaux and the personal and professional characteristics of those who work in them form the empirical core of the present study. The findings presented are based on the responses of 29 Legal Advice Bureaux supervisors and 273 lawyers from a stratified multi-stage varying probability sample of four urban areas in New Zealand. Response rates were 71.9% (N = 32) and 84.5% (N = 323) respectively. Data are presented in 50 in-text tables. Whilst finding some support for its propositions, the study concludes by raising some problems in Johnson's theory of the professions which remain to be solved
Acousto-optic effect compensation for optical determination of the normal velocity distribution associated with acoustic transducer radiation
Author Posting. © Acoustical Society of America, 2015. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 138 (2015): 1627, doi:10.1121/1.4929372.The acousto-optic effect, in which an acoustic wave causes variations in the optical index of refraction, imposes a fundamental limitation on the determination of the normal velocity, or normal displacement, distribution on the surface of an acoustic transducer or optically reflecting pellicle by a scanning heterodyne, or homodyne, laser interferometer. A general method of compensation is developed for a pulsed harmonic pressure field, transmitted by an acoustic transducer, in which the laser beam can transit the transducer nearfield. By representing the pressure field by the Rayleigh integral, the basic equation for the unknown normal velocity on the surface of the transducer or pellicle is transformed into a Fredholm equation of the second kind. A numerical solution is immediate when the scanned points on the surface correspond to those of the surface area discretization. Compensation is also made for oblique angles of incidence by the scanning laser beam. The present compensation method neglects edge waves, or those due to boundary diffraction, as well as effects due to baffles, if present. By allowing measurement in the nearfield of the radiating transducer, the method can enable quantification of edge-wave and baffle effects on transducer radiation. A verification experiment has been designed
Biomechanical analysis of the Achilles tendon enthesis organ
The tendon/ligament insertional region is a common site of injury, despite the protection offered by the surrounding tissues. These tissues, termed the enthesis organ, form a concept that has only recently been developed and thus has been the focus of only a few publications. The work in this thesis is the first study to perform a biomechanical analysis of the enthesis organ, providing information that may potentially improve injury management methods. A thorough assessment of the enthesis organ biomechanics was made using a number of techniques. Dissecting room cadavers allowed for micro- and macroscopic examination, whilst magnetic resonance imaging and ultrasound provided in vivo images and movie files. Specially fabricated apparatuses were also developed to investigate the load bearing and lubrication regime. A number of the structures within the enthesis organ were identified as being of biomechanical importance. The paratenon/deep fascia was recognised as influencing the insertional angle of the Achilles tendon, possibly in tandem with the superior tuberosity. It was Kager's fat pad, however, that appeared the most highly specialised and influential tissue. This is currently excised when performing arthroscopic ankle surgery, although microscopic examination revealed a highly specialised structure with 3 separate regions. These appeared to allow independent movement of its distal wedge into the retrocalcaneal bursa, a movement that was hypothesised to both equalise a pressure change and to lubricate the contacting surfaces of the enthesis organ. This work concludes that the surgical removal of Kager's fat pad is likely to starve the Achilles tendon enthesis organ of a number of biomechanical functions performed by this tissue, and thus may influence pain relief post-operatively. The excision of the superior tuberosity, however, appears insignificant as it not believed to increase the likelihood of enthesis failure, although preservation of both the superior tuberosity and the deep fascia/paratenon would ensure continued regulation of the Achilles tendon insertion angle
3D printed origami honeycombs with tailored out-of-plane energy absorption behavior
Honeycomb structures display extraordinary stiffness-to-weight ratio when loaded in the out-of-plane direction. When realized using thermoplastic polyurethane (TPU), the structures offer the potential for repeatable and high specific energy absorption. Varying the cell size and wall thickness of TPU honeycombs facilitates changes in stiffness magnitude, though affords only modest capacity to alter the shape of the stress-strain curve. 3D printing facilitates advanced design exploration, beyond that of straight walls. Origami fold patterns have demonstrated the ability to influence the buckling behavior of tubular structures. Here we demonstrate the incorporation of origami folds into square honeycombs. The fold parameters facilitate significant tailoring of the stress-strain curve, allowing a range of profiles from quasi-rectangular to quasi-linear to be achieved; such structures can find applications in situation-specific energy absorption scenarios
Skin tribology in sport
This review describes the principles of skin friction and wear for the benefit of sports scientists, engineers and clinicians. Skin exhibits complex behaviour, defying tribological laws for dry contact; hence, its friction and wear characteristics are affected by sliding speed, normal load, and contact area. Some sports seek to increase skin friction to enhance performance; however, this needs to be offset against injury risk given that skin abrades when slid across a rough and hard surface, delaminates when slid across a smooth and hard surface, and chafes or blisters when repeatedly rubbed against some fabrics. Whilst skin interactions can both define and hinder athlete performance, there exists a need to better understand skin biomechanics to optimise the balance of risk versus reward
On the AIC-based model reduction for the general Holzapfel–Ogden myocardial constitutive law
© 2019, The Author(s). Constitutive laws that describe the mechanical responses of cardiac tissue under loading hold the key to accurately model the biomechanical behaviour of the heart. There have been ample choices of phenomenological constitutive laws derived from experiments, some of which are quite sophisticated and include effects of microscopic fibre structures of the myocardium. A typical example is the strain-invariant-based Holzapfel–Ogden 2009 model that is excellently fitted to simple shear tests. It has been widely used and regarded as the state-of-the-art constitutive law for myocardium. However, there has been no analysis to show if it has both adequate descriptive and predictive capabilities for other tissue tests of myocardium. Indeed, such an analysis is important for any constitutive laws for clinically useful computational simulations. In this work, we perform such an analysis using combinations of tissue tests, uniaxial tension, biaxial tension and simple shear from three different sets of myocardial tissue studies. Starting from the general 14-parameter myocardial constitutive law developed by Holzapfel and Ogden, denoted as the general HO model, we show that this model has good descriptive and predictive capabilities for all the experimental tests. However, to reliably determine all 14 parameters of the model from experiments remains a great challenge. Our aim is to reduce the constitutive law using Akaike information criterion, to maintain its mechanical integrity whilst achieving minimal computational cost. A competent constitutive law should have descriptive and predictive capabilities for different tissue tests. By competent, we mean the model has least terms but is still able to describe and predict experimental data. We also investigate the optimal combinations of tissue testsfor a given constitutive model. For example, our results show thatusing one of the reduced HO models, one mayneed just one shear response (along normal-fibredirection) and one biaxial stretch (ratio of 1 mean fibre : 1 cross-fibre) to satisfactorily describe Sommer et al. human myocardial mechanical properties. Our studysuggests that single-state tests (i.e. simple shear or stretching only) are insufficient to determine the myocardium responses. We also foundit is important to consider transmural fibre rotations within eachmyocardial sampleof tests during the fitting process.This is done byexcluding un-stretched fibres usingan “effective fibre ratio”, which depends on the sample size, shape, local myofibre architecture and loading conditions. We conclude that a competent myocardium material model can be obtained from the general HO model using AIC analysis and a suitable combination of tissue tests
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