An optimisation approach to the location and sizing of multiple leaks in a duct

A single leak in a duct can be located, and its size predicted, by measuring the input impedance of the duct and then solving an inverse problem. However, extending this procedure to a duct containing several leaks is non-trivial, with the resulting mathematical expressions proving to be highly complex. In this paper, an optimisation approach to the location and sizing of multiple leaks in a duct is described. The approach employs a standard theoretical model of a duct that contains several leaks. The initial parameters of the duct model (e.g. duct radius, number of leaks, leak positions and sizes) are chosen arbitrarily. An optimisation function then adjusts the parameters of the model until its input impedance matches the measured impedance of the duct under investigation. Results are presented which demonstrate the success of this optimisation approach in both locating and sizing multiple leaks in a duct

TRADE NEGOTIATIONS AND THE FUTURE OF AMERICAN AGRICULTURE

International Relations/Trade,

Surface Ruptures Observed at Ejido Saltillo, Baja California after the Mexicali Valley Earthquake of 9 June, 1980

Following the 9 June 1980 earthquake near Victoria, Baja California, J. J. Lienkaemper and I briefly investigated the Imperial fault in California to determine whether a new pulse of after slip of the 15 October 1979 earthquake might have been triggered by the new seismic event. On June 12, we checked the Imperial fault in Mexico for evidence of new displacement, as well as several locations along the Cerro Prieto fault in the epicentral region (Figure 7.1). On returning by way of Ejido Saltillo, our car reported a vertical offset in the pavement of Pascualitos-Pescaderos highway with a provocative jolt. The local farmers’ knowledge of new ruptures greatly expedited our subsequent observations, which are briefly summarized here

Smart helmet: wearable multichannel ECG & EEG

Modern wearable technologies have enabled continuous recording of vital signs, however, for activities such as cycling, motor-racing, or military engagement, a helmet with embedded sensors would provide maximum convenience and the opportunity to monitor simultaneously both the vital signs and the electroencephalogram (EEG). To this end, we investigate the feasibility of recording the electrocardiogram (ECG), respiration, and EEG from face-lead locations, by embedding multiple electrodes within a standard helmet. The electrode positions are at the lower jaw, mastoids, and forehead, while for validation purposes a respiration belt around the thorax and a reference ECG from the chest serve as ground truth to assess the performance. The within-helmet EEG is verified by exposing the subjects to periodic visual and auditory stimuli and screening the recordings for the steady-state evoked potentials in response to these stimuli. Cycling and walking are chosen as real-world activities to illustrate how to deal with the so-induced irregular motion artifacts, which contaminate the recordings. We also propose a multivariate R-peak detection algorithm suitable for such noisy environments. Recordings in real-world scenarios support a proof of concept of the feasibility of recording vital signs and EEG from the proposed smart helmet

Visualising gas heating from an RF plasma loudspeaker

In an electro-acoustic transduction mechanism, an ac modulation (here in the audio frequency range) of the electric field in an atmospheric pressure air plasma gives rise to a rapid increase in the gas temperature and dimensions of the gas volume. As in natural lightning, the rapid expansion in the ionised column though the air produces external pressure variations at the modulation frequency.  \ud Spatial and temporal measurement of the gas temperature can identify the nature of the thermal expansion and provide a direct approach to understanding its relationship to the sound pressure wave that is generated. However, the established method through spectroscopic measurement of rotational line emission from nitrogen molecules is limited to the main current channel where relaxation and subsequent optical emission of the excited nitrogen molecules occurs. The wider picture is revealed through the use of the Schlieren method where the refractive index gradients caused by gas heating in the plasma are imaged

The Team of Life: A narrative approach to building resilience in UK school children

Concern about children and young people's mental health is high on the UK national agenda. Access to specialist Child and Adolescent Mental Health Services (CAMHS) is perceived as problematic due to high thresholds, clinic-based service delivery and associated stigma. Schools and youth work contexts present alternative and more accessible settings for early intervention and preventative work aimed at promoting positive mental health. The Team of Life is a narrative group methodology with sporting metaphors, which encourages young people to recognise the strength and resilience in their life teams. The approach has been used within diverse contexts internationally, for example with former child soldiers in Uganda, young men from refugee backgrounds and young people in Australian schools. Innovative partnership work between health and education has led to the implementation of the Team of Life in a UK school and the development of a manualised Team of Life Programme. We now report findings from pilot work evaluating feasibility and outcomes for the programme within a UK secondary school setting. Quantitative findings include significant positive change in Goal Based Outcomes as well as significant reductions in emotional and behaviour difficulties measured by the Child Behaviour Checklist. Qualitative thematic analysis of participant feedback indicates benefits relating to the experience of 'shared understanding', 'confidence', 'peer support' and the 'positive impact of sport'. Further research is planned to evaluate the effectiveness on a larger scale. This pilot study was undertaken as part of CAMHS Extended Schools work. Potential for collaboration between clinical and education psychology colleagues in relation to the promotion of positive mental health in schools is discussed

Unsung heroes: who supports social work students on placement?

Since the introduction of the three year degree programme in 2003, social work education has undergone a number of significant changes. The time students spend on placement has been increased to two hundred days, and the range of placement opportunities and the way in which these placements have been configured has significantly diversified. A consistent feature over the years, however, has been the presence of a Practice Educator (PE) who has guided, assessed and taught the student whilst on placement. Unsurprisingly, the role of the PE and the pivotal relationship they have with the student has been explored in the past and features in social work literature. This paper, however, concentrates on a range of other relationships which are of significance in providing support to students on placement. In particular it draws on research to discuss the role of the university contact tutor, the place of the wider team in which the student is sited, and the support offered by family, friends and others. Placements and the work undertaken by PE’s will continue to be integral to the delivery of social work education. It is, however, essential to recognise and value the often over looked role of others in providing support to students on placement