33,008 research outputs found

    Evolution of a localized thermal explosion in a reactive gas

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    Experimental observations of ignition in premixed gaseous reactants indicate that perfectly homogeneous initiation is practically unrealizable. Instead, combustion first sets in, as a rule, at small, discrete sites where inherent inhomogeneities cause chemical activity to proceed preferentially and lead to localized explosions. Combustion waves propagating away from these hot spots or reaction centers eventually envelop the remaining bulk. This study examines the spatial structure and temporal evolution of a hot spot for a model involving Arrhenius kinetics. The hot spot, characterized by peaks in pressure and temperature with little diminution in local density, is shown to have one of two possible self-similar structures. The analysis employs a combination of asymptotics and numerics, and terminates when pressure and temperature in the explosion have peaked

    Human factors aspects of control room design: Guidelines and annotated bibliography

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    A human factors analysis of the workstation design for the Earth Radiation Budget Satellite mission operation room is discussed. The relevance of anthropometry, design rules, environmental design goals, and the social-psychological environment are discussed

    The effect of consumption volume on profile and liking of oral nutritional supplements of varied sweetness: sequential profiling and boredom tests

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    Oral nutrition supplements (ONS) are routinely prescribed to those with, or at risk of, malnutrition. Previous research identified poor compliance due to taste and sweetness. This paper investigates taste and hedonic liking of ONS, of varying sweetness and metallic levels, over consumption volume; an important consideration as patients are prescribed large volumes of ONS daily. A sequential descriptive profile was developed to determine the perception of sensory attributes over repeat consumption of ONS. Changes in liking of ONS following repeat consumption were characterised by a boredom test. Certain flavour (metallic taste, soya milk flavour) and mouthfeel (mouthdrying, mouthcoating) attributes built up over increased consumption volume (p 0.002). Hedonic liking data from two cohorts, healthy older volunteers (n = 32, median age 73) and patients (n = 28, median age 85), suggested such build-up was disliked. Efforts made to improve the palatability of ONS must take account of the build up of taste and mouthfeel characteristics over increased consumption volume

    Earthquake-Rotated Headstones as a Means of Re-evaluating Epicentral Location of the 1944 Massena-Cornwall Earthquake: New York, United States and Ontario, Canada

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    The Massena-Cornwall earthquake (September 5th, 1944) is the largest earthquake in New York state history. Two epicenters have been previously proposed (Milne, 1949; Dewey and Gordon, 1984); however, they are separated by 15 km, an error that could associate each proposed epicenter with two different local faults. Due to the lack of standardized seismic-array data, there is value in approaching this event using an unconventional data set. The methodology of MacDonald and Wentworth (1952) was executed through ArcMap 10.5.1 to yield an area most likely to contain the epicenter. One-hundred fifty-four earthquake-rotated headstones from 15 cemeteries within ~35 km of Massena, New York/Cornwall, Ontario were measured for angle of rotation via a digital goniometer (0.1 ̊ resolution). The mean angle of rotation is 1.9° (cf., 0.1° for unaffected, post-1944 headstones: p\u3c0.0001), independent of rotation direction. Factoring in the average strike of headstones in each cemetery, an octant was projected based on whether the cemetery had predominantly experienced clockwise or counter-clockwise rotation. The area of densest overlap between the projected octants is an ~20km2 area centered in the Saint Lawrence River (proposed epicenter at N45.014, W74.815) six miles northeast of Massena, NY. This area is bisected by the Gloucester Fault; an extension of the Ottawa-Bonnechere Graben. This project is an improvement on previous studies of the 1944-rotated headstones (e.g., Berkey, 1945) by analyzing quantitative rotational data within an ArcMap framework. These refined data implicate a rupture along an extension of the Gloucester Fault—a potential threat to the nearby Moses-Saunders Power Dam

    Geology

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    Papers from private industry reporting applications of remote sensing to oil and gas exploration were presented. Digitally processed LANDSAT images were successfully employed in several geologic interpretations. A growing interest in digital image processing among the geologic user community was shown. The papers covered a wide geographic range and a wide technical and application range. Topics included: (1) oil and gas exploration, by use of radar and multisensor studies as well as by use of LANDSAT imagery or LANDSAT digital data, (2) mineral exploration, by mapping from LANDSAT and Skylab imagery and by LANDSAT digital processing, (3) geothermal energy studies with Skylab imagery, (4) environmental and engineering geology, by use of radar or LANDSAT and Skylab imagery, (5) regional mapping and interpretation, and digital and spectral methods

    Perspectives on financial incentives to health service providers for increasing breast feeding and smoking quit rates during pregnancy: a mixed methods study

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    Objective: To explore the acceptability, mechanisms and consequences of provider incentives for smoking cessation and breast feeding as part of the Benefits of Incentives for Breastfeeding and Smoking cessation in pregnancy (BIBS) study. Design: Cross-sectional survey and qualitative interviews. Setting: Scotland and North West England. Participants: Early years professionals: 497 survey respondents included 156 doctors; 197 health visitors/maternity staff; 144 other health staff. Qualitative interviews or focus groups were conducted with 68 pregnant/postnatal women/family members; 32 service providers; 22 experts/decision-makers; 63 conference attendees. Methods: Early years professionals were surveyed via email about the acceptability of payments to local health services for reaching smoking cessation in pregnancy and breastfeeding targets. Agreement was measured on a 5-point scale using multivariable ordered logit models. A framework approach was used to analyse free-text survey responses and qualitative data. Results: Health professional net agreement for provider incentives for smoking cessation targets was 52.9% (263/497); net disagreement was 28.6% (142/497). Health visitors/maternity staff were more likely than doctors to agree: OR 2.35 (95% CI 1.51 to 3.64; p<0.001). Net agreement for provider incentives for breastfeeding targets was 44.1% (219/497) and net disagreement was 38.6% (192/497). Agreement was more likely for women (compared with men): OR 1.81 (1.09 to 3.00; p=0.023) and health visitors/maternity staff (compared with doctors): OR 2.54 (95% CI 1.65 to 3.91; p<0.001). Key emergent themes were 'moral tensions around acceptability', 'need for incentives', 'goals', 'collective or divisive action' and 'monitoring and proof'. While provider incentives can focus action and resources, tensions around the impact on relationships raised concerns. Pressure, burden of proof, gaming, box-ticking bureaucracies and health inequalities were counterbalances to potential benefits. Conclusions: Provider incentives are favoured by non-medical staff. Solutions which increase trust and collaboration towards shared goals, without negatively impacting on relationships or increasing bureaucracy are required

    Study of the Cir X--1 Broad Band Spectrum at Orbital Phases Close to the Apoastron

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    We report on the results of a BeppoSAX (1.8--200 keV) observation of the peculiar X-ray binary source Circinus X--1 (Cir X--1) at the orbital phases between 0.61 and 0.63. We find that three components are needed to fit the broad band spectrum: a blackbody component, at a temperature of 0.6\sim 0.6 keV, a Comptonized component, with a seed-photon temperature of 1.2\sim 1.2 keV, electron temperature of 6\sim 6 keV and optical depth of 1.7\sim 1.7, and a power-law component dominating the spectrum at energies higher than 20 keV. We interpret the blackbody as the emission from the accretion disk, while the Comptonized component probably comes from a corona surrounding the inner part of the system. This spectrum is different from that observed at the periastron (Iaria et al. 2001a) because of the presence of the blackbody component. We discuss the implications of this difference and the presence of the power-law component.Comment: 15 pages, 6 figures, accepted by Ap

    Laser-Derived, Particle Size Data from CRP-2/2A: Implications for Sequence and Seismic Stratigraphy

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    Gravel-free, high-resolution (1-metre spacing, 32 channel) particle size data from the CRP-2/2A drill core indicate that many of the diamictites were likely deposited from floating ice. Textural dislocations occur at most sequence boundaries and provide independent corroboration of the sequence stratigraphic interpretation. Likewise the data largely support the correlation drawn (Fielding et al., this volume) between the sequence stratigraphic cycles and the regional seismic stratigraphy (an alternative correlation to Reflector ‘f’ is also suggested). The gravel-free data appear to be reflecting predominantly regional (global?) forcing with some possible local effects, and long-term trends persisting through gravelly textural dislocations
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