11,214 research outputs found
Cathedral Chimes : Reverie For Piano
https://digitalcommons.library.umaine.edu/mmb-ps/1438/thumbnail.jp
A Preventable Epidemic
The purpose of this study is to provide an awareness of the magnitude of accidents as the leading cause of death among Indian people and the fourth leading cause of death for non-Indians, and to provide a comparison of the injuries, deaths, and their cost for the years 1977 and 1979 for the reservation residents living in South Dakota
On the accuracy of conservation of adiabatic invariants in slow-fast systems
Let the adiabatic invariant of action variable in slow-fast Hamiltonian
system with two degrees of freedom have two limiting values along the
trajectories as time tends to infinity. The difference of two limits is
exponentially small in analytic systems. An iso-energetic reduction and
canonical transformations are applied to transform the slow-fast systems to
form of systems depending on slowly varying parameters in a complexified phase
space. On the basis of this method an estimate for the accuracy of conservation
of adiabatic invariant is given for such systems.Comment: 27 pages, 14 figure
Online Drift Compensation for Chemical Sensors Using Estimation Theory
Sensor drift from slowly changing environmental conditions and other instabilities can greatly degrade a chemical sensor\u27s performance, resulting in poor identification and analyte quantification. In the present work, estimation theory (i.e., various forms of the Kalman filter) is used for online compensation of baseline drift in the response of chemical sensors. Two different cases, which depend on the knowledge of the characteristics of the sensor system, are studied. First, an unknown input is considered, which represents the practical case of analyte detection and quantification. Then, the more general case, in which the sensor parameters and the input are both unknown, is studied. The techniques are applied to simulated sensor data, for which the true baseline and response are known, and to actual liquid-phase SH-SAW sensor data measured during the detection of organophosphates. It is shown that the technique is capable of estimating the baseline signal and recovering the true sensor signal due only to the presence of the analyte. This is true even when the baseline drift changes rate or direction during the detection process or when the analyte is not completely flushed from the system
Sports performers' perspectives on facilitating thriving in professional rugby contexts
ObjectivesThe desire and apparent ‘need’ to succeed can drive a win-at-all-costs mentality in individuals who operate in sport. This approach has given rise to environments where the pursuit of high-level performance has been at the expense of athlete welfare. To redress this balance and to inform the creation and maintenance of sporting environments that promote both high performance and athlete well-being, we sought to (i) provide an exploration of the environmental factors that may promote player thriving in professional sport, and (ii) offer suggestions for how key stakeholders can support these mechanisms.DesignA qualitative research methodology underpinned by ontological relativism and epistemological constructionism.MethodSemi-structured interviews were conducted with 18 players from an English professional rugby union club.ResultsThematic analysis generated thirteen factors that players perceived to promote thriving. These factors were underpinned by two general ideas: (i) Establishing Bonds between Teammates and (ii) Establishing a Connection to the Coaching Staff and the Club.ConclusionsThe findings provide the first insight into the type of environment professional rugby players believe can facilitate their development and sporting success. The factors generated in the analysis highlight the players’ desire to operate within an integrated, inclusive, and trusting environment, and a variety of suggestions are forwarded for how this can be achieved. To promote thriving in a professional sport that requires emotion and passion to succeed on the pitch, it appears that rugby union organizations must appeal to the sensitivities and welfare of players off it
Analysis of the Detection of Organophosphate Pesticides in Aqueous Solutions Using Polymer-Coated SH-SAW Devices
Organophosphate pesticides (OPs) have been found as contaminants in surface and ground waters, soil, and agricultural products. Because OPs are toxic compounds, rapid detection/monitoring of OPs in groundwater is necessary to allow for real-time remediation. Detection of OPs in water has already been demonstrated using poly(epichlorohydrin) [PECH] and polyurethane as the sensing layers. However, the response times were relatively long, hindering real-time monitoring. In this work, a hybrid organic/inorganic chemically sensitive layer [bisphenol A-hexamethyltrisiloxane (BPA-HMTS)] that shows a high degree of partial selectivity for OPs is synthesized, characterized (in terms of the glass transition temperature, Tg, water stability, sensitivity, selectivity, detection limit, and absorption/response time) for the rapid detection of organophosphate pesticides. Direct chemical sensing in aqueous solutions is performed using guided shear horizontal surface acoustic wave sensor platforms on 36° rotated Y-cut LiTaO3 and 42.75° rotated Y-cut Quartz, respectively. It is shown that, for the same coating thickness, a 60% reduction in sensor response time is achieved without reduction in sensitivity compared to PECH. Considering the Tg, for the polymers, it is seen that the faster response shown by BPA-HMTS is due to the porous siloxane backbone, HMTS. Kinetic studies for the absorption of OPs (parathion-methyl, parathion, and paraoxon) from aqueous solutions into the BPA-HMTS coating are conducted. The data are analyzed within the context of two absorption models: penetration-limited and diffusion-limited absorptions. It is shown that the absorption process is rate limited by penetration with a concentration independent absorption time constant or mass transfer coefficient. The absorption time constants for parathion-methyl, parathion, and paraoxon are calculated. A limit of detection of 60, 20 and 100 μg/L (ppb) for parathion-methyl, parathion, and paraoxon, respectively, is calculated for the present non-optimized sensor. Concentrations as low as 500 μg/L (ppb) parathion are actually measured. This is much lower than the typical concentrations found on agricultural produce (≥ 10 ppm).
Furthermore, sensor signal analysis in the form of the extended Kalman filter (EKF) is employed on-line during the detection process. The sensor response was first represented by a state-space model which includes all relevant contributions to the polymer-coated device response. This allows for the steady-state response and absorption time constant to be extracted on-line well before the steady-state is reached, thus further reducing the time for analyte identification and quantification. It is noted the absorption time constant, often unique to a class of analyte-coating pairs, can be used to improve analyte recognition
Analysis of the Detection of Organophosphate Pesticides in Aqueous Solutions Using Hydrogen-Bond Acidic Coating on SH-SAW Devices
The work presented in this paper focuses on the synthesis and characterization of a hybrid organic/inorganic chemically sensitive layer for rapid detection and analysis of OPs in aqueous solutions using SH-SAW devices. Coated SH-SAW devices on 36° YX-LiTaO and 42.75° YX-Quartz (ST-90° X Quartz), are used to determine the optimum operating conditions for achieving rapid sensor responses with high sensitivity. Three analytes (parathion-methyl, parathion, and paraoxon), having similar molecular mass and volume, are used to evaluate the performance of the hybrid organic/inorganic coating in terms of sensor properties of interest including sensitivity, selectivity, reproducibility. It is shown that the coating has a high degree of partial selectivity and sensitivity towards the analytes. With the present non-optimized chemical sensor, a limit of detection of 60 (ppb), 20 (ppb) and 100 (ppb) is estimated for parathion-methyl, parathion, and paraoxon, respectively, when using a 0.5 -thick BPA-HMTS sensing layer. Concentrations as low as 500 (ppb) parathion have been measured. This concentration is significantly much lower than the typical concentrations found on agricultural produce (≥10 ppm)
High-Sensitivity Magnetic Sensors Based on GMI Microwire-SAW IDT Design
This work presents a design approach for a highly sensitive, miniaturized magnetic sensor. The design makes use of GMI microwires and a multi-electrode SAW IDT. The use of SAW IDTs allows for the magnetic effect of the GMI microwire to be measured through the transduction process. This approach permits simultaneous measurement at different frequencies of operation, enabling highly sensitive measurement over a wide range of magnetic fields. This technique may find application in magnetic sensing for non-invasive battery SOC measurement
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