554 research outputs found
Fluid Phase Separation (FPS) experiment for flight on a space shuttle Get Away Special (GAS) canister
The separation of fluid phases in microgravity environments is of importance to environmental control and life support systems (ECLSS) and materials processing in space. A successful fluid phase separation experiment will demonstrate a proof of concept for the separation technique and add to the knowledge base of material behavior. The phase separation experiment will contain a premixed fluid which will be exposed to a microgravity environment. After the phase separation of the compound has occurred, small samples of each of the species will be taken for analysis on the Earth. By correlating the time of separation and the temperature history of the fluid, it will be possible to characterize the process. The experiment has been integrated into space available on a manifested Get Away Special (GAS) experiment, CONCAP 2, part of the Consortium for Materials Complex Autonomous Payload (CAP) Program, scheduled for STS-42. The design and the production of a fluid phase separation experiment for rapid implementation at low cost is presented
Using task farming to optimise a street-scale resolution air quality model of the West Midlands (UK)
High resolution air quality models combining emissions, chemical processes, dispersion and dynamical treatments are necessary to develop effective policies for clean air in urban environments, but can have high computational demand. We demonstrate the application of task farming to reduce runtime for ADMS-Urban, a quasi-Gaussian plume air dispersion model. The model represents the full range of source types (point, road and grid sources) occurring in an urban area at high resolution. Here, we implement and evaluate the option to automatically split up a large model domain into smaller sub-regions, each of which can then be executed concurrently on multiple cores of a HPC or across a PC network, a technique known as task farming. The approach has been tested for a large model domain covering the West Midlands, UK (902 km2), as part of modelling work in the WM-Air (West Midlands Air Quality Improvement Programme) project. Compared to the measurement data, overall, the model performs well. Air quality maps for annual/subset averages and percentiles are generated. For this air quality modelling application of task farming, the optimisation process has reduced weeks of model execution time to approximately 35 h for a single model configuration of annual calculations
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The CU mobile Solar Occultation Flux instrument: structure functions and emission rates of NH₃, NO₂ and C₂H₆
We describe the University of Colorado mobile Solar Occultation Flux instrument (CU mobile SOF). The instrument consists of a digital mobile solar tracker that is coupled to a Fourier transform spectrometer (FTS) of 0.5 cm−1 resolution and a UV–visible spectrometer (UV–vis) of 0.55 nm resolution. The instrument is used to simultaneously measure the absorption of ammonia (NH3), ethane (C2H6) and nitrogen dioxide (NO2) along the direct solar beam from a moving laboratory. These direct-sun observations provide high photon flux and enable measurements of vertical column densities (VCDs) with geometric air mass factors, high temporal resolution of 2 s and spatial resolution of 5–19 m. It is shown that the instrument line shape (ILS) of the FTS is independent of the azimuth and elevation angle pointing of the solar tracker. Further, collocated measurements next to a high-resolution FTS at the National Center for Atmospheric Research (HR-NCAR-FTS) show that the CU mobile SOF measurements of NH3 and C2H6 are precise and accurate; the VCD error at high signal to noise ratio is 2–7 %. During the Front Range Air Pollution and Photochemistry Experiment (FRAPPE) from 21 July to 3 September 2014 in Colorado, the CU mobile SOF instrument measured median (minimum, maximum) VCDs of 4.3 (0.5, 45)  ×  1016 molecules cm−2 NH3, 0.30 (0.06, 2.23)  ×  1016 molecules cm−2 NO2 and 3.5 (1.5, 7.7)  ×  1016 molecules cm−2 C2H6. All gases were detected in larger 95 % of the spectra recorded in urban, semi-polluted rural and remote rural areas of the Colorado Front Range. We calculate structure functions based on VCDs, which describe the variability of a gas column over distance, and find the largest variability for NH3. The structure functions suggest that currently available satellites resolve about 10 % of the observed NH3 and NO2 VCD variability in the study area. We further quantify the trace gas emission fluxes of NH3 and C2H6 and production rates of NO2 from concentrated animal feeding operations (CAFO) using the mass balance method, i.e., the closed-loop vector integral of the VCD times wind speed along the drive track. Excellent reproducibility is found for NH3 fluxes and also, to a lesser extent, NO2 production rates on 2 consecutive days; for C2H6 the fluxes are affected by variable upwind conditions. Average emission factors were 12.0 and 11.4 gNH3 h−1 head−1 at 30 °C for feedlots with a combined capacity for  ∼  54 000 cattle and a dairy farm of  ∼  7400 cattle; the pooled rate of 11.8 ± 2.0 gNH3 h−1 head−1 is compatible with the upper range of literature values. At this emission rate the NH3 source from cattle in Weld County, CO (535 766 cattle), could be underestimated by a factor of 2–10. CAFO soils are found to be a significant source of NOx. The NOx source accounts for  ∼  1.2 % of the N flux in NH3 and has the potential to add  ∼  10 % to the overall NOx emissions in Weld County and double the NOx source in remote areas. This potential of CAFO to influence ambient NOx concentrations on the regional scale is relevant because O3 formation is NOx sensitive in the Colorado Front Range. Emissions of NH3 and NOx are relevant for the photochemical O3 and secondary aerosol formation
Mapping urban green infrastructure : a novel landscape-based approach to incorporating land-use and land-cover in the mapping of human-dominated systems
Common approaches to mapping green infrastructure in urbanized landscapes invariably focus on measures of land-use or land-cover and associated functional or physical traits. However, such one-dimensional perspectives do not accurately capture the character and complexity of the landscapes in which urban inhabitants live. The new approach presented in this paper demonstrates how open-source, high spatial and temporal resolution data with global coverage can be used to measure and represent the landscape qualities of urban environments. Through going beyond simple metrics of quantity, such as percentage green and blue cover it is now possible to explore the extent to which landscape quality helps to unpick the mixed evidence presented in the literature on the benefits of urban nature to human well-being. Here we present a landscape approach, employing remote sensing, GIS and data reduction techniques, to map urban green infrastructure elements in a large UK city-region. Comparison with existing urban datasets demonstrates considerable improvement in terms of coverage and thematic detail. The characterisation of landscapes, using census tracts as spatial units, and subsequent exploration of associations with social-ecological attributes highlights the further detail which can be uncovered with the approach. For example, eight urban landscape types identified for the case study city exhibited associations with distinct socio-economic conditions accountable not only to quantities but also qualities of green and blue space. The identification of individual landscape features through simultaneous measures of land-use and land cover demonstrated unique and significant associations between the former and indicators of human health and ecological condition. The approach may therefore provide a promising basis for developing further insight into the processes and characteristics which affect human health and wellbeing in urban areas, both in the UK and beyond
Effects of Inherent Tissue Anisotropy on Measurements Obtained with a Clinical Ultrasonic Imaging System
Our overall goal is to develop clinically applicable tissue characterization methods, based on quantitative analyses of backscattered ultrasound, which can differentiate normal from diseased heart segments. In implementing these methods there is a need to compensate for the inherent anisotropic properties of the heart that are exhibited in echocardiographic images. [1–4] Furthermore, quantitative tissue characterization methods may be able to exploit the inherent anisotropy of the myocardium to achieve assessment of cardiac properties.[5–9] The specific aims of this investigation were to measure the spectral properties of backscattered ultrasound using a clinical imaging system and to determine effects of inherent tissue anisotropy on measured spectral properties of backscattered ultrasound
The HANDE-QMC Project: Open-Source Stochastic Quantum Chemistry from the Ground State Up.
Building on the success of Quantum Monte Carlo techniques such as diffusion Monte Carlo, alternative stochastic approaches to solve electronic structure problems have emerged over the past decade. The full configuration interaction quantum Monte Carlo (FCIQMC) method allows one to systematically approach the exact solution of such problems, for cases where very high accuracy is desired. The introduction of FCIQMC has subsequently led to the development of coupled cluster Monte Carlo (CCMC) and density matrix quantum Monte Carlo (DMQMC), allowing stochastic sampling of the coupled cluster wave function and the exact thermal density matrix, respectively. In this Article, we describe the HANDE-QMC code, an open-source implementation of FCIQMC, CCMC and DMQMC, including initiator and semistochastic adaptations. We describe our code and demonstrate its use on three example systems; a molecule (nitric oxide), a model solid (the uniform electron gas), and a real solid (diamond). An illustrative tutorial is also included
Discovery of a nanodiamond-rich layer in the Greenland ice sheet
We report the discovery in the Greenland ice sheet of a discrete layer of free nanodiamonds (NDs) in very high abundances, implying most likely either an unprecedented influx of extraterrestrial (ET) material or a cosmic impact event that occurred after the last glacial episode. From that layer, we extracted n-diamonds and hexagonal diamonds (lonsdaleite), an accepted ET impact indicator, at abundances of up to about 5!106 times background levels in adjacent younger and older ice. The NDs in the concentrated layer are rounded, suggesting they most likely formed during a cosmic impact through some process similar to carbon-vapor deposition or high-explosive detonation. This morphology has not been reported previously in cosmic material, but has been observed in terrestrial impact material. This is the first highly enriched, discrete layer of NDs observed in glacial ice anywhere, and its presence indicates that ice caps are important archives of ET events of varying magnitudes. Using a preliminary ice chronology based on oxygen isotopes and dust stratigraphy, the ND-rich layer appears to be coeval with ND abundance peaks reported at numerous North American sites in a sedimentary layer, the Younger Dryas boundary layer (YDB), dating to 12.9 0.1 ka. However, more investigation is needed to confirm this association
The Vehicle, 1961, Vol. 3 no. 2
Vol. 3, No. 2
Table of Contents
The Voting CattleLinda Kay Campbellpage 5
But For the Passage of TimeDon Shepardsonpage 14
LoveJon Woodspage 16
Infinite JourneyJames E. Martinpage 19
The Clover ChainRichard W. Blairpage 20
SnowballSusan Daughertypage 24
Sureness Is NeverDon Shepardsonpage 26
ConceptionChristine McCollpage 34
Comedy: Relief and GriefTom McPeakpage 35
The Unspoken WordChristine McCollpage 35
CharmBenjamin Polkpage 36
Screaming SpiderTom McPeakpage 39
Just Once in an Early SpringE.J.B.page 39
HummingbirdPauline B. Smithpage 40
Willow TreesPauline B. Smithpage 40
MaturityChristine McCollpage 41
The New YearLinda Campbellpage 41
The StormMary-Jean Pitratpage 42
Ebony IvoryJean Danenbargerpage 42
The Fireball MailAllen Engelbrightpage 43
ExpectationChristine McCollpage 44
CatastropheChristine McCollpage 44
SophisticationBenjamin Polkpage 45
On Playing BridgeMyrna Jo Handleypage 46
SonnetMignon Stricklandpage 48https://thekeep.eiu.edu/vehicle/1009/thumbnail.jp
The Vehicle, 1961, Vol. 3 no. 2
Vol. 3, No. 2
Table of Contents
The Voting CattleLinda Kay Campbellpage 5
But For the Passage of TimeDon Shepardsonpage 14
LoveJon Woodspage 16
Infinite JourneyJames E. Martinpage 19
The Clover ChainRichard W. Blairpage 20
SnowballSusan Daughertypage 24
Sureness Is NeverDon Shepardsonpage 26
ConceptionChristine McCollpage 34
Comedy: Relief and GriefTom McPeakpage 35
The Unspoken WordChristine McCollpage 35
CharmBenjamin Polkpage 36
Screaming SpiderTom McPeakpage 39
Just Once in an Early SpringE.J.B.page 39
HummingbirdPauline B. Smithpage 40
Willow TreesPauline B. Smithpage 40
MaturityChristine McCollpage 41
The New YearLinda Campbellpage 41
The StormMary-Jean Pitratpage 42
Ebony IvoryJean Danenbargerpage 42
The Fireball MailAllen Engelbrightpage 43
ExpectationChristine McCollpage 44
CatastropheChristine McCollpage 44
SophisticationBenjamin Polkpage 45
On Playing BridgeMyrna Jo Handleypage 46
SonnetMignon Stricklandpage 48https://thekeep.eiu.edu/vehicle/1009/thumbnail.jp
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