Total focussing method for volumetric imaging in immersion non destructive evaluation

This paper describes the use of a 550 (25x22) element 2MHz 2D piezoelectric composite array in immersion mode to image an aluminum test block containing a collection of artificial defects. The defects included a 1mm diameter side-drilled hole, a collection of 1mm slot defects with varying degrees of skew to the normal and a flat bottomed hole. The data collection was carried out using the full matrix capture; a scanning procedure was developed to allow the operation of the large element count array through a conventional 64-channel phased array controller. A 3D TFM algorithm capable of imaging in a dual media environment was implemented in MATLAB for the offline processing the raw scan data. This algorithm facilitates the creation of 3D images of defects while accounting for refraction effects at material boundaries. In each of the test samples interrogated the defects, and their spatial position, are readily identified using TFM. Defect directional information has been characterized using VTFM for defect exhibiting angles up to and including 45o of skew

Using privacy calculus theory to explore entrepreneurial directions in mobile location-based advertising: Identifying intrusiveness as the critical risk factor

Location-based advertising is an entrepreneurial and innovative means for advertisers to reach out through personalised messages sent directly to mobile phones using their geographic location. The mobile phone users' willingness to disclose their location and other personal information is essential for the successful im- plementation of mobile location-based advertising (MLBA). Despite the potential enhancement of the user ex- perience through such personalisation and the improved interaction with the marketer, there is an increasing tension between that personalisation and mobile users' concerns about privacy. While the privacy calculus theory (PCT) suggests that consumers make privacy-based decisions by evaluating the benefits any information may bring against the risk of its disclosure, this study examines the specific risks and benefits that influence consumers' acceptance of MLBA. A conceptual model is proposed based on the existing literature and a stan- dardised survey was developed and targeted at individuals with known interests in the subject matter. From these requests, 252 valid responses were received and used to evaluate the key benefits and risks of MLBA from the users' perspectives. While the results confirmed the importance of internet privacy concerns (IPC) as an important determinant, they also indicate that monetary rewards and intrusiveness have a notably stronger impact on acceptance intentions towards MLBA. Intrusiveness is the most important risk factor in determining mobile users' intentions to accept MLBA and therefore establishing effective means of minimising the perceived intrusiveness of MLBA can be expected to have the greatest impact on achieving effective communications with mobile phone users

Nuclear alpha-clustering, superdeformation, and molecular resonances

Nuclear alpha-clustering has been the subject of intense study since the advent of heavy-ion accelerators. Looking back for more than 40 years we are able today to see the connection between quasimolecular resonances in heavy-ion collisions and extremely deformed states in light nuclei. For example superdeformed bands have been recently discovered in light N=Z nuclei such as $^{36}$Ar, $^{40}$Ca, $^{48}$Cr, and $^{56}$Ni by $\gamma$-ray spectroscopy. The search for strongly deformed shapes in N=Z nuclei is also the domain of charged-particle spectroscopy, and our experimental group at IReS Strasbourg has studied a number of these nuclei with the charged particle multidetector array {\sc Icare} at the {\sc Vivitron} Tandem facility in a systematical manner. Recently the search for $\gamma$-decays in $^{24}$Mg has been undertaken in a range of excitation energies where previously nuclear molecular resonances were found in $^{12}$C+$^{12}$C collisions. The breakup reaction $^{24}$Mg$+^{12}$C has been investigated at E$_{lab}$($^{24}$Mg) = 130 MeV, an energy which corresponds to the appropriate excitation energy in $^{24}$Mg for which the $^{12}$C+$^{12}$C resonance could be related to the breakup resonance. Very exclusive data were collected with the Binary Reaction Spectrometer in coincidence with {\sc Euroball IV} installed at the {\sc Vivitron}.Comment: 10 pages, 4 eps figures included. Invited Talk 10th Nuclear Physics Workshop Marie and Pierre Curie, Kazimierz Dolny Poland, Sep. 24-28, 2003; To be published in International Journal of Modern Physics

Hypervelocity Stars from the Andromeda Galaxy

Hypervelocity stars (HVSs) discovered in the Milky Way (MW) halo are thought to be ejected from near the massive black hole (MBH) at the galactic centre. In this paper we investigate the spatial and velocity distributions of the HVSs which are expected to be similarly produced in the Andromeda galaxy (M31). We consider three different HVS production mechanisms: (i) the disruption of stellar binaries by the galactocentric MBH; (ii) the ejection of stars by an in-spiraling intermediate mass black hole; and (iii) the scattering of stars off a cluster of stellar-mass black holes orbiting around the MBH. While the first two mechanisms would produce large numbers of HVSs in M31, we show that the third mechanism would not be effective in M31. We numerically calculate 1.2*10^6 trajectories of HVSs from M31 within a simple model of the Local Group and hence infer the current distribution of these stars. Gravitational focusing of the HVSs by the MW and the diffuse Local Group medium leads to high densities of low mass (~ solar mass) M31 HVSs near the MW. Within the virialized MW halo, we expect there to be of order 1000 HVSs for the first mechanism and a few hundred HVSs for the second mechanism; many of these stars should have distinctively large approach velocities (< -500 km/s). In addition, we predict ~5 hypervelocity RGB stars within the M31 halo which could be identified observationally. Future MW astrometric surveys or searches for distant giants could thus find HVSs from M31.Comment: 14 pages, 6 figures, changed to match version accepted by MNRA

An agrogeophysical modelling framework for the detection of soil compaction spatial variability due to grazing using field-scale electromagnetic induction data.

Soil compaction is a regarded as a major environmental and economical hazard, degrading soils across the world. Changes in soil properties due to compaction are known to lead to decrease in biomass and increase in greenhouse gas emissions, nutrient leaching and soil erosion. Quantifying adverse impacts of soil compaction and developing strategies for amelioration relies on an understanding of soil compaction extent and temporal variability. The main indicators of soil compaction (i.e., reduction of pore space, increase in bulk density and decrease in soil transport properties) are relatively easy to quantify in laboratory conditions but such traditional point-based methods offer little information on soil compaction extent at the field scale. Recently, geophysical methods have been proposed to provide non-invasive information about soil compaction. In this work, we developed an agrogeophysical modelling framework to help address the challenges of characterizing soil compaction across grazing paddocks using electromagnetic induction (EMI) data. By integrative modelling of grazing, soil compaction, soil processes and EMI resistivity anomalies, we demonstrate how spatial patterns of EMI observations can be linked to management leading to soil compaction and concurrent modifications of soil functions. The model was tested in a dairy farm in the midlands of Ireland that has been grazed for decades and shows clear signatures of grazing-induced compaction. EMI data were collected in the summer of 2021 and autumn of 2022 under dry and wet soil moisture conditions, respectively. For both years, we observed decreases of apparent electrical resistivity at locations that with visible signatures of compaction such as decreased vegetation and water ponding (e.g., near the water troughs and gates). A machine learning algorithm was used to cluster EMI data with three unique cluster signatures assumed to be representative of heavy, moderately, and non-compacted field zones. We conducted 1D process-based simulations corresponding to non-compacted and compacted soils. The modelled EMI signatures agree qualitatively and quantitatively with the measured EMI data, linking decreased electrical resistivities to zones that were visibly compacted. By providing a theoretical framework based on mechanistic modelling of soil management and compaction, our work may provide a strategy for utilizing EMI data for detection of soil degradation due to compaction

Export Tourism Input-Output Multipliers for Ireland. Quarterly Economic Commentary Special Article, May 1982

This paper focuses on some difficulties involved in the interpretation of earlier studies and goes on to calculate upper bound estimates of some of the principal economic effects of Irish export tourism in 1976. The 1976 input-output data of Henry (1980) form the basis for the calculations herein

Receptor-type Guanylyl Cyclases Confer Thermosensory Responses in C. elegans.

Thermosensation is critical for optimal regulation of physiology and behavior. C. elegans acclimates to its cultivation temperature (Tc) and exhibits thermosensitive behaviors at temperatures relative to Tc. These behaviors are mediated primarily by the AFD sensory neurons, which are extraordinarily thermosensitive and respond to thermal fluctuations at temperatures above a Tc-determined threshold. Although cGMP signaling is necessary for thermotransduction, the thermosensors in AFD are unknown. We show that AFD-specific receptor guanylyl cyclases (rGCs) are instructive for thermosensation. In addition to being necessary for thermotransduction, ectopic expression of these rGCs confers highly temperature-dependent responses onto diverse cell types. We find that the temperature response threshold is determined by the rGC and cellular context, and that multiple domains contribute to their thermosensory properties. Identification of thermosensory rGCs in C. elegans provides insight into mechanisms of thermosensation and thermal acclimation and suggests that rGCs may represent a new family of molecular thermosensors.This work was funded in part by the NIH (R01 GM081639 and P01 GM103770 – P.S., T32007292 – V.M.H. and P01NS079419 - T.O.).This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.neuron.2016.03.00