Analysis of the free vibration of a coupled plate/fluid interacting system and interpretation using sub-system modal energy

This paper describes a method for describing and quantifying the vibratory behaviour of interacting structural/fluid systems based upon reference to the relative energy associated with each of the sub-systems. The particular case selected is that of a circular plate in interaction with a cylindrical fluid cavity. A theoretical analysis is performed, based upon the Euler Bernoulli and Helmholtz equations combined through a Galerkin technique, from which the natural frequencies and associated mode functions of the interacting system are calculated. The convergence of the analysis is investigated and the opportunity is taken to investigate the sensitivity of the coupled natural frequencies to different assumed mode shapes of the plate in vacuo. Subsequently the coupled mode functions are used to describe details of the energy associated with the plate and the fluid. It is found that presentation of these relative energies renders a satisfactory insight into the vibration behaviour of the coupled system

The timing and magnitude of upper body muscular activity during a field hockey hit

The aim of this study was to investigate the contributions to stick motion in the field hockey hit by monitoring muscle activity in the arms and trunk and synchronising these with arm and stick kinematics. The hits of ten male, university-level field hockey players were analysed. Whilst their interpretation is complicated by the closed kinetic loop formed by the arms and stick, the data collected here represent a step forward in establishing the contributions from muscular activity and segmental interactions to the field hockey hit. This study has shown that EMG analysis alone is not sufficient to explain the nature of muscular activity patterns and that the temporal aspects of EMG need to be examined in combination with kinematic data to ascertain the role of muscular activity during movement

How young people from culturally and linguistically diverse backgrounds experience mental health: some insights for mental health nurses

This article reports on a part of a study which looked at the mental health of culturally and linguistically diverse (CALD) young people. The research sought to learn from CALD young people, carers, and service providers experiences relevant to the mental health of this group of young people. The ultimate goal was to gain insights that would inform government policy, service providers, ethnic communities and most importantly the young people themselves. To this end, qualitative interviews were undertaken with 123 CALD young people, 41 carers and 14 mental health service providers in Queensland, Western Australia and South Australia. Only one aspect of the study will be dealt with here, namely the views of the young CALD participants, which included risk factors, coping strategies and recommendations about how they could be supported in their struggle to maintain mental health. One of the most important findings of the study relates to the resilience of these young people and an insight into the strategies that they used to cope. The efforts of these young people to assist us in our attempts to understand their situation deserve to be rewarded by improvements in the care that we provide. To this end this article sets out to inform mental health nurses of the results of the study so that they will be in a position to better understand the needs and strengths of their CALD clients and be in a better position to work effectively with them

Compact Toroidal Ion Trap Design and Optimization

We present the design of a new type of compact toroidal, or "halo", ion trap. Such traps may be useful for mass spectrometry, studying small Coulomb cluster rings, quantum information applications, or other quantum simulations where a ring topology is of interest. We present results from a Monte Carlo optimization of the trap design parameters using finite-element analysis simulations that minimizes higher-order anharmonic terms in the trapping pseudopotential, while maintaining complete control over ion placement at the pseudopotential node in 3D using static bias fields. These simulations are based on a practical electrode design using readily-available parts, yet can be easily scaled to any size trap with similar electrode spacings. We also derive the conditions for a crystal phase transition for two ions in the compact halo trap, the first non-trivial phase transition for Coulomb crystals in this geometry.Comment: 8 pages, 9 figure

Approaching Questions of Text Reuse in Ancient Greek Using Computational Syntactic Stylometry

We are investigating methods by which data from dependency syntax treebanks of ancient Greek can be applied to questions of authorship in ancient Greek historiography. From the Ancient Greek Dependency Treebank were constructed syntax words (sWords) by tracing the shortest path from each leaf node to the root for each sentence tree. This paper presents the results of a preliminary test of the usefulness of the sWord as a stylometric discriminator. The sWord data was subjected to clustering analysis. The resultant groupings were in accord with traditional classifications. The use of sWords also allows a more fine-grained heuristic exploration of difficult questions of text reuse. A comparison of relative frequencies of sWords in the directly transmitted Polybius book 1 and the excerpted books 9–10 indicate that the measurements of the two texts are generally very close, but when frequencies do vary, the differences are surprisingly large. These differences reveal that a certain syntactic simplification is a salient characteristic of Polybius’ excerptor, who leaves conspicuous syntactic indicators of his modifications

Ionospheric effects on one-way timing signals

A proposed navigation concept requires that a user measure the time-delay that satellite-emitted signals experience in traversing the distance between satellite and user. Simultaneous measurement of the propagation time from four different satellites permits the user to determine his position and clock bias if satellite ephemerides and signal propagation velocity are known. A pulse propagating through the ionosphere is slowed down somewhat, giving an apparent range that is larger than the equivalent free space range. The difference between the apparent range and the true range, or the free space velocity and the true velocity, is the quantity of interest. This quantity is directly proportional to the total electron content along the path of the propagating signal. Thus, if the total electron content is known, or is measured, a perfect correction to ranging could be performed. Faraday polarization measurements are continuously being taken at Fort Monmouth, N. J., using beacon emissions of the ATS-3 (137.35 MHz) satellite. Day-to-day variability of the diurnal variation of total electron content values is present with differences of up to 50% or more not being uncommon. In addition, superposed on the overall diurnal variation are smaller scale variations of approximately 5 to 10% of the total content which are attributed to ionospheric density irregularities

Plasmaspheric effects on one way satellite timing signals

The effects of the ionospheric retardation of satellite-emitted timing signals was presented. The retardation at the navigation frequencies, which is proportional to the total ionospheric electron content (TEC), was determined by Faraday polarization measurements of VHF emissions of a geostationary satellite. The polarization data yielded TEC up to approximately 1200 km only, since the measurement technique is based on the Faraday effect which is weighted by the terrestrial magnetic field