A Preliminary Study of Solar Powered Aircraft and Associated Power Trains

The feasibility of regeneratively powered solar high altitude powered platform (HAPP) remotely piloted vehicles was assessed. Those technologies which must be pursued to make long duration solar HAPPs feasible are recommended. A methodology which involved characterization and parametric analysis of roughly two dozen variables to determine vehicles capable of fulfilling the primary mission are defined. One of these vehicles was then conceptually designed. Variations of each major design parameter were investigated along with state-of-the-art changes in power train component capabilities. The midlatitude mission studied would be attainable by a solar HAPP if fuel cell, electrolyzer and photovoltaic technologies are pursued. Vehicles will be very large and have very lightweight structures in order to attain the combinations of altitude and duration required by the primary mission

Estimating Canopy Gap Fraction Using ICESat GLAS within Australian Forest Ecosystems

Spaceborne laser altimetry waveform estimates of canopy Gap Fraction (GF) vary withrespect to discrete return airborne equivalents due to their greater sensitivity to reflectance differencesbetween canopy and ground surfaces resulting from differences in footprint size, energy thresholding,noise characteristics and sampling geometry. Applying scaling factors to either the ground or canopyportions of waveforms has successfully circumvented this issue, but not at large scales. This studydevelops a method to scale spaceborne altimeter waveforms by identifying which remotely-sensedvegetation, terrain and environmental attributes are best suited to predicting scaling factors basedon an independent measure of importance. The most important attributes were identified as: soilphosphorus and nitrogen contents, vegetation height, MODIS vegetation continuous fields productand terrain slope. Unscaled and scaled estimates of GF are compared to corresponding ALS datafor all available data and an optimized subset, where the latter produced most encouraging results(R2 = 0.89, RMSE = 0.10). This methodology shows potential for successfully refining estimates ofGF at large scales and identifies the most suitable attributes for deriving appropriate scaling factors.Large-scale active sensor estimates of GF can establish a baseline from which future monitoringinvestigations can be initiated via upcoming Earth Observation missions

ATTITUDE DETERMINATION OF A STUDENT SATELLITE USING ON-ORBIT MAGNETOMETER AND TEMPERATURE DATA

An extended Kalman filter is modified to support only magnetometer data as a measurement for spacecraft attitude information. Actual on-orbit data from a student satellite is used in the filter from three different time periods and varying data frequencies. The extended Kalman filter has a thermal model that utilizes external temperature data as a verification tool for filter convergence and for parameter tuning. It can capture the frequency of temperature changes and the correct side panel being lit by the sun as long as the filter converges properly, but not the magnitude of the temperature at a specific time. A solar panel power model is also attempted, which was found to be unusable due to power budget issues and the side panel current sensors railing. Convergence of the three sets of data showed that a 30 second snapshot rate converges to a more accurate attitude information when the satellite has a 0.1 rev/min rotation rate compared to the 1.0 rev/min rotation rate data. A 10 second snapshot rate gives more accurate attitude information for data from a satellite with a 1.0 rev/min rotation rate. By investigating the drastic reduction in the satellite’s rotation rate over 6 months, it was discovered that the satellite’s antenna is most likely magnetized, causing it to try to align itself with the Earth’s magnetic field, slowing down the rotation rate of the satellite from 1 rev/min to 0.1 rev/min

Whose turn is it anyway : the impact of job rotation on the reduction of cumulative trauma disorders

In today\u27s fast-paced world, repetitive activity on the job has become very demanding. Many workers are suffering from injuries known as cumulative trauma disorders (CTDs). Job rotation can be an effective and powerful tool when seeking to minimize CTDs by allowing workers to experience different activities, thereby distributing the physical demands on the workers\u27 bodies. A case study was conducted on a northwestern New York manufacturing facility to identify the presence of excessive work stressors and to formulate potential corrective actions, including an analysis of their current job rotation system. The jobs were evaluated using the Rapid Upper Limb Assessment. This study provides valuable information on the benefits of an effective job rotation system, and the steps necessary to implement one. For the case study, a reduction of exposure to work stressors of 20.9% for the Overall Risk Index can be accomplished using the new job rotation system methods

Winter diet, seed preferences and foraging behavior of Henslow\u27s Sparrows (Ammodramus henslowii) in southeastern Louisiana

Henslow\u27s Sparrow (Ammodramus henslowii) is a grassland bird whose population is declining throughout its range, mainly due to habitat loss. The Longleaf Pine forest ecosystems in which Henslow\u27s Sparrows spend their winters are reduced to 5% of their former range. The winter ecology of Henslow\u27s Sparrow remains understudied, especially regarding important aspects of diet and foraging behavior. To determine winter diet, I collected fecal samples from Henslow\u27s Sparrows during banding operations in southeastern Louisiana pine savannas from October 2003-March 2004 and October 2004-April 2005. I then analyzed the samples for presence of seeds and arthropod parts, identified them to the lowest classification possible, and then used both multivariate and univariate techniques to look for variations in diet due to a savannas burn history, month of year and their interaction. I also conducted multiple-offer and simple-offer seed preference experiments on captive Henslow\u27s Sparrows in December 2004 and February 2005 to test a variety of seed types found at differing abundances within the study sites. Commonly consumed seeds included Scleria spp., Rhynchospora spp., the category including Dichanthelium spp. and Panicum spp., and the combined category of Aristida spp., Schizachyrium spp. and Andropogon spp. Frequently consumed arthropods included Arachnids and insects from the orders Coleoptera, Hymenoptera, Hemiptera and Orthoptera. Diets varied significantly among months, most likely due to resource availability and timing of seed senescence. Results of seed preference experiments suggest that Henslow\u27s Sparrows preferred Dichanthelium angustifolium, Muhlenbergia expansa and Eupatorium leucolepis while they avoided Schizachyrium scoparium. Ctenium aromaticum and Panicum anceps appeared to be secondarily preferred food items

Timing of migration and patterns of winter settlement by Henslow\u27s Sparrows

Fall arrival is an important period in the life history of migratory birds because processes during this period determine where birds spend the winter, which is linked to subsequent survival and condition at the time of spring migration. Henslow\u27s Sparrows (Ammodramus henslowii) winter in savannas of longleaf pine (Pinus palustris), but their secretive behavior limits our knowledge of their winter ecology, including behavioral processes that lead to their documented preference of an ephemeral habitat-recently burned savannas. We expected that upon arrival Henslow\u27s Sparrows actively seek out recently burned savannas and that their over-winter location is dependent on intraspecific interactions during the arrival period. We conducted a 2-year mark-recapture study in southeastern Louisiana longleaf pine savannas to examine these predictions. Bird densities were highest in savannas burned during the previous growing season. There was a large turnover of transient individuals in October and early November, but the proportion of dispersing birds was not related to the number of years since fire or to the bird\u27s age or sex. Early-season movements did not result in skewed age or sex distributions associated with years since fire, suggesting the lack of a class-mediated competitive hierarchy. Birds were then site faithful from late November through spring departure, which began in March and lasted through mid April, with males departing first. © The Cooper Ornithological Society 2009

Seed preferences of wintering Henslow\u27s sparrows

The Henslow\u27s Sparrow (Ammodramus henslowii), a species of conservation concern, winters primarily in longleaf pine (Pinus palustris) forest ecosystems in the southeastern U.S. These pine savannas have been reduced to 5% of their former range, with remaining patches requiring active management with fire to maintain characteristic structure and plant diversity. Wintering Henslow\u27s Sparrow abundance tracks growing-season fires; bird abundance peaks in the winter following burning, then declines in subsequent winters. Fire also determines dominant plant species, suggesting that Henslow\u27s Sparrows may respond to abundance of preferred seeds. To determine diet preferences of Henslow\u27s Sparrows, we tested seeds from eight species of native plants from southeastern Louisiana pine savannas, including species common in the first winter after burning (\u27fire grasses\u27) and species that increase in abundance in the second and subsequent winters after burning. Seed consumption by individual birds differed considerably, suggesting that Henslow\u27s Sparrows forage on a variety of resources in the highly diverse savannas. Henslow\u27s Sparrows preferred fire grasses, especially Muhlenbergia expansa (cutover muhly). They also preferred Dichanthelium angustifolium (needleleaf rosette grass), a species more common in the second year after burning, but consumed relatively little of the sedges Rhynchospora plumosa (plumed beaksedge) and R. gracilenta (slender beaksedge), species common in the second winter after fire. Birds consumed almost none of the ubiquitous grass Schizachyrium scoparium (little bluestem). These results suggest that preferred seeds may include those that are most common in the first winter after burning, but that some suitable seeds are available for at least another winter. © The Cooper Ornithological Society 2007

Biophysical characterization of protected areas globally through optimized image segmentation and classification

Protected areas (PAs) need to be assessed systematically according to biodiversity values and threats in order to support decision-making processes. For this, PAs can be characterized according to their species, ecosystems and threats, but such information is often difficult to access and usually not comparable across regions. There are currently over 200,000 PAs in the world, and assessing these systematically according to their ecological values remains a huge challenge. However, linking remote sensing with ecological modelling can help to overcome some limitations of conservation studies, such as the sampling bias of biodiversity inventories. The aim of this paper is to introduce eHabitat+, a habitat modelling service supporting the European Commission's Digital Observatory for Protected Areas, and specifically to discuss a component that systematically stratifies PAs into different habitat functional types based on remote sensing data. eHabitat+ uses an optimized procedure of automatic image segmentation based on several environmental variables to identify the main biophysical gradients in each PA. This allows a systematic production of key indicators on PAs that can be compared globally. Results from a few case studies are illustrated to show the benefits and limitations of this open-source tool