4,902 research outputs found
Consolidated Space Test Center Capability to Support Small Satellites
No analysis of small satellite programs is complete without thorough consideration of the operational concept that will support them. It is not uncommon today that a space system\u27s lifecycle cost will show that operating costs exceeded development and production costs. This is particularly true for programs that hope to reduce spacecraft expense by transferring, to the ground, as much of the on-board processing requirements as operationally feasible. Facility, hardware, software, maintenance, manning, training, communications, on-orbit operations and launch costs all factor into the total operations spending and must be prudently considered
Satellite-Derived Bathymetry Using Multiple Images: The Alaska North Slope Case Study
Currently, charting data in much of the U.S. Arctic North Slope is inadequate or nonexistent and most of its areas have not been updated since the early-1950s. Although the charting infrastructure is out of date, ship transportation (such as, fishing and transit between the towns) has increased. NOAA conducted a preliminary multibeam survey in 2013 that reached Point Barrow, AK. However, all the Arctic North Slope remained untouched. Previous studies have shown that satellite-derived bathymetry (SDB) is a useful reconnaissance tool in tropical and sub-tropical waters in clear water conditions, especially over sandy seafloor. However, it is very difficult to extract good information over the Arctic using a single satellite image, especially over the U.S. North Slope. The glacial powder from land reduces the water clarity that limits the light penetration depth. Also, this turbidity is not uniform along the coast line and may affect the calculations. In this paper, a new SDB approach was developed that compiles multiple satellite images to extract only areas that were identified clear by comparison (i.e., minimum water clarity change between two satellite images). Preliminary results using Landsat 7 imagery from 1999-2002 and Landsat 8 imagery from 2013 are presented
Nautical Chart Adequacy Evaluation Using Publicly-Available Data
The International Hydrographic Office (IHO) C-55 publication communicates the need to improve the collection, quality and availability of hydrographic data world-wide, while also monitoring and rectifying possible deficiencies and shortcomings that are presented on the chart. This task of evaluating the adequacy of nautical chart products poses a challenge to many national hydrographic offices. This stems from the dearth of readily available spatial information: namely, the lack of reliable and accessible vessel traffic data, and little means to assess the changing nature of both near-shore bathymetry and shoreline in a simple and reliable manner. In this paper, we present the potential use of automatic-identification system (AIS) data, satellite-derived bathymetry (SDB), and airborne-lidar bathymetry (ALB) to provide an operational procedure for evaluating the adequacy and completeness of information of NOAA charts. Preliminary results from three U.S. study sites are presented in this paper: Nantucket Sound, MA; Barnegat Bay Inlet, NJ; and Barataria Bay, LA. Based on the publically-available datasets it was possible to identify changes in the charts and develop a reconnaissance procedure to monitor these changes on a yearly basis
"It's all interconnected… like a spider web": a qualitative study of the meanings of food and healthy eating in an Indigenous community.
Canadian Indigenous populations are disproportionately affected by rising rates of diet-related chronic disease and have been experiencing rapid lifestyle changes affecting diet. In recognition of these issues, this study aimed to obtain greater understanding of attitudes and meanings around healthy eating in a semi-remote community in Eeyou Istchee. A qualitative study design used semi-structured interviews and observational field notes to explore local accounts of food and health. Two distinct versions of "healthy eating" were identified: one relating to traditional food and preparation methods; the other reflecting medicalised accounts of illness and diagnosed conditions. The latter links with "southern" modes of accessing and preparing food, demonstrating local capacity to adapt to the rapid changes in body, lifestyle and environment being experienced. New connections, associating non-native ways with traditional practices, are being formed where traditional ways of living on the land have been severed. These local accounts show how people are continually negotiating different constructs of "healthy eating." These findings expand current understandings of the context of food and healthy eating in Eeyou Istchee, emphasising present-day and historical experiences of the land. Future research and diet-related health interventions must continue to acknowledge and incorporate local understandings of health to help address the broader socio-political factors that shape Indigenous lifestyles, environments and health
Fusing Information in a 3D Chart-of-the-Future Display
The Data Visualization Research Lab at the Center for Coastal and Ocean Mapping is investigating how three-dimensional navigational displays can most effectively be constructed. This effort is progressing along multiple paths and is implemented in the GeoNav3D system, a 3D chart-of-the-future research prototype. We present two lines of investigation here. First, we explore how tide, depth, and planning information can be combined (fused) into a single view, in order to give the user a more realistic picture of effective water depths. In the GeoNav3D system, 3D shaded bathymetry, coded for color depth, is used to display navigable areas. As in ENC displays, different colors are used to easily identify areas that are safe, areas where under-keel clearance is minimal, and areas where depths are too shallow. Real-time or model-generated tide information is taken into account in dynamically color-coding the depths. One advantage to using a continuous bathymetric model, versus discrete depth areas, is that the model can be continuously adjusted for water level. This concept is also extended for planning purposes by displaying the color-coded depths along a proposed corridor at the expected time of reaching each point. In our second line of investigation, we explore mechanisms for linking information from multiple 3D views into a coherent whole. In GeoNav3D, it is possible to create a variety of plan and perspective views, and these views can be attached to moving reference frames. This provides not only semi-static views such as from-the-bridge and under-keel along-track profile views, but also more dynamic, interactive views. These views are linked through visual devices that allow the fusion of information from among the views. We present several such devices and show how they highlight relevant details and help to minimize user confusion. Investigation into the utility of various linked views for aiding realsituation decision-making is ongoin
GeoZui3D: Data Fusion for Interpreting Oceanographic Data
GeoZui3D stands for Geographic Zooming User Interface. It is a new visualization software system designed for interpreting multiple sources of 3D data. The system supports gridded terrain models, triangular meshes, curtain plots, and a number of other display objects. A novel center of workspace interaction method unifies a number of aspects of the interface. It creates a simple viewpoint control method, it helps link multiple views, and is ideal for stereoscopic viewing. GeoZui3D has a number of features to support real-time input. Through a CORBA interface external entities can influence the position and state of objects in the display. Extra windows can be attached to moving objects allowing for their position and data to be monitored. We describe the application of this system for heterogeneous data fusion, for multibeam QC and for ROV/AUV monitoring
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Emissions from village cookstoves in Haryana, India, and their potential impacts on air quality
Air quality in rural India is impacted by residential cooking and heating with biomass fuels. In this study, emissions of CO, CO2, and 76 volatile organic compounds (VOCs) and fine particulate matter (PM2.5) were quantified to better understand the relationship between cook fire emissions and ambient ozone and secondary organic aerosol (SOA) formation. Cooking was carried out by a local cook, and traditional dishes were prepared on locally built chulha or angithi cookstoves using brushwood or dung fuels. Cook fire emissions were collected throughout the cooking event in a Kynar bag (VOCs) and on polytetrafluoroethylene (PTFE) filters (PM2.5). Gas samples were transferred from a Kynar bag to previously evacuated stainless-steel canisters and analyzed using gas chromatography coupled to flame ionization, electron capture, and mass spectrometry detectors. VOC emission factors were calculated from the measured mixing ratios using the carbon-balance method, which assumes that all carbon in the fuel is converted to CO2, CO, VOCs, and PM2.5 when the fuel is burned. Filter samples were weighed to calculate PM2.5 emission factors. Dung fuels and angithi cookstoves resulted in significantly higher emissions of most VOCs (p < 0.05). Utilizing dung-angithi cook fires resulted in twice as much of the measured VOCs compared to dung-chulha and 4 times as much as brushwood-chulha, with 84.0, 43.2, and 17.2g measured VOCkgg fuel carbon, respectively. This matches expectations, as the use of dung fuels and angithi cookstoves results in lower modified combustion efficiencies compared to brushwood fuels and chulha cookstoves. Alkynes and benzene were exceptions and had significantly higher emissions when cooking using a chulha as opposed to an angithi with dung fuel (for example, benzene emission factors were 3.18gkgg fuel carbon for dung-chulha and 2.38gkgg fuel carbon for dung-angithi). This study estimated that 3 times as much SOA and ozone in the maximum incremental reactivity (MIR) regime may be produced from dung-chulha as opposed to brushwood-chulha cook fires. Aromatic compounds dominated as SOA precursors from all types of cook fires, but benzene was responsible for the majority of SOA formation potential from all chulha cook fire VOCs, while substituted aromatics were more important for dung-angithi. Future studies should investigate benzene exposures from different stove and fuel combinations and model SOA formation from cook fire VOCs to verify public health and air quality impacts from cook fires
Molecular composition of particulate matter emissions from dung and brushwood burning household cookstoves in Haryana, India
Emissions of airborne particles from biomass burning are a significant source of black carbon (BC) and brown carbon (BrC) in rural areas of developing countries where biomass is the predominant energy source for cooking and heating. This study explores the molecular composition of organic aerosols from household cooking emissions with a focus on identifying fuel-specific compounds and BrC chromophores. Traditional meals were prepared by a local cook with dung and brushwood-fueled cookstoves in a village in Palwal district, Haryana, India. Cooking was done in a village kitchen while controlling for variables including stove type, fuel moisture, and meal. Fine particulate matter (PM2.5) emissions were collected on filters, and then analyzed via nanospray desorption electrospray ionization-high-resolution mass spectrometry (nano-DESI-HRMS) and high-performance liquid chromatography-photodiode array-high-resolution mass spectrometry (HPLC-PDA-HRMS) techniques. The nano-DESI-HRMS analysis provided an inventory of numerous compounds present in the particle phase. Although several compounds observed in this study have been previously characterized using gas chromatography methods a majority of the species in the nano-DESI spectra were newly observed biomass burning compounds. Both the stove (chulha or angithi) and the fuel (brushwood or dung) affected the composition of organic aerosols. The geometric mean of the PM2.5 emission factor and the observed molecular complexity increased in the following order: brushwood-chulha (7.3±1.8 g kg-1 dry fuel, 93 compounds), dung-chulha (21.1±4.2 g kg-1 dry fuel, 212 compounds), and dung-angithi (29.8±11.5 g kg-1 dry fuel, 262 compounds). The mass-normalized absorption coefficient (MACbulk) for the organic-solvent extractable material for brushwood PM2.5 was 3.7±1.5 and 1.9±0.8m2 g-1 at 360 and 405 nm, respectively, which was approximately a factor of two higher than that for dung PM2.5. The HPLC-PDA-HRMS analysis showed that, regardless of fuel type, the main chromophores were CxHyOz lignin fragments. The main chromophores accounting for the higher MACbulk values of brushwood PM2.5 were C8H10O3 (tentatively assigned to syringol), nitrophenols C8H9NO4, and C10H10O3 (tentatively assigned to methoxycinnamic acid)
Electronic Chart of the Future: The Hampton Roads Project
ECDIS is evolving from a two-dimensional static display of chart-related data to a decision support system capable of providing real-time or forecast information. While there may not be consensus on how this will occur, it is clear that to do this, ENC data and the shipboard display environment must incorporate both depth and time in an intuitively understandable way. Currently, we have the ability to conduct high-density hydrographic surveys capable of producing ENCs with decimeter contour intervals or depth areas. Yet, our existing systems and specifications do not provide for a full utilization of this capability. Ideally, a mariner should be able to benefit from detailed hydrographic data, coupled with both forecast and real-time water levels, and presented in a variety of perspectives. With this information mariners will be able to plan and carry out transits with the benefit of precisely determined and easily perceived underkeel, overhead, and lateral clearances. This paper describes a Hampton Roads Demonstration Project to investigate the challenges and opportunities of developing the “Electronic Chart of the Future.” In particular, a three-phase demonstration project is being planned: 1. Compile test datasets from existing and new hydrographic surveys using advanced data processing and compilation procedures developed at the University of New Hampshire’s Center for Coastal and Ocean Mapping/Joint Hydrographic Center (CCOM/JHC); 2. Investigate innovative approaches being developed at the CCOM/JHC to produce an interactive time- and tide-aware navigation display, and to evaluate such a display on commercial and/or government vessels; 3. Integrate real-time/forecast water depth information and port information services transmitted via an AIS communications broadcast
Arterial pathophysiology and comparison of two devices for pulse wave velocity assessment in elderly men: the British regional heart study.
Objective: Vascular disease is highly prevalent in the elderly. This study aimed to evaluate arterial phenotype in elderly men and compare carotid-femoral pulse wave velocity (cfPWV) assessed by two techniques (Sphygmocor (S)and Vicorder (V)). Methods: 1722 men (72-92 years), participants in the British Regional Heart Study, underwent ultrasound assessment of carotid intima-media thickness (cIMT), carotid distensibility coefficient and presence of carotid plaque. cfPWV and ankle brachial pressure index (ABPI) were also assessed. 123 men returned for between visit reproducibility assessments. Results: Good reproducibility was demonstrated in all measures (Gwet's agreement=0.8 for plaque, intraclass correlation=0.65 for ABPI and coefficient of variation 90% of men for all measures except cfPWV(S) and ABPI. In 1122 men with both cfPWV(V) and cfPWV(S) data, cfPWV(S) was greater than cfPWV(V) (mean difference=0.23,95%CI 0.10 to 0.37 m/s). cfPWV(V) was higher at low cfPWV values and cfPWV(S) was higher at high cfPWV values. Correlation of V transit time (TT) against S carotid and femoral TT demonstrated that the slope of the regression line for femoral TT was steeper than for carotid TT, resulting in a proportionally greater subtraction of carotid TT from femoral TT at higher PWVs. Conclusions: Reproducible, satisfactory quality non-invasive measurements of vascular phenotype were obtainable in a large proportion of elderly men. The discrepancy in results between the two PWV measures may partly be due to the differential impact of subtracting carotid TT when deriving cfPWV(S) across the clinical PWV range
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