1,744 research outputs found

    Validation of a geographic information system predictive habitat model for burrowing owls (Athene cunicularia) at US Army, Dugway Proving Ground

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    Department Head: Michael J. Manfredo.2009 Spring.Includes bibliographical references (pages 25-26).This study was designed to validate the use of Geological Information Systems (GIS) for creating a predictive habitat model that produces raster maps of acceptable habitats for Burrowing Owls, Athene cunicularia (ATCU). The model was designed to locate ATCU habitat for long-term monitoring purposes at U.S. Army Dugway Proving Ground. ArcGIS 9 was used to manipulate data from three data layers: Southwest Regional Gap Analysis vegetation layer, slope data, and proximity to edge. A weighted index was assigned to individual pixels. The weighted index was a product of the weighting factors (0.45, 0.35, and 0.25 for vegetation types, slope and proximity, respectively times the index (3, 2, 1, 0 for excellent, fair, poor and non-habitat, respectively). The display layer was the sum of the weighted layers. The display was Excellent, Fair, Poor and Non- Habitat. Visual and auditory field observations were conducted in each of the four habitat delineations to validate the models predictive capability. In conclusion, we could not discriminate Excellent, Fair, Poor, or Non-habitat, based on the two proportions test and the Z-statistic at the 80% Confidence Interval. Validation was hampered by the low incidence of ATCU sightings in the 2008 season

    Multiplicity of the Protostar Serpens SMM 1 Revealed by Millimeter Imaging

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    The Serpens SMM 1 region was observed in the 6.9 mm continuum with an angular resolution of about 0.6 arcsec. Two sources were found to have steep positive spectra suggesting emission from dust. The stronger one, SMM 1a, is the driving source of the bipolar jet known previously, and the mass of the dense molecular gas traced by the millimeter continuum is about 8 solar mass. The newly found source, SMM 1b, positionally coincides with the brightest mid-IR source in this region, which implies that SMM 1b is yet another young stellar object. SMM 1b seems to be less deeply embedded than SMM 1a. SMM 1 is probably a protobinary system with a projected separation of 500 AU

    Accumulators for the Capture of Heavy Metals in Thermal Conversion Systems

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    International audienceA clay ceramic with organic additives (biomass and biochar) was investigated for the development of highly porous accumulators to capture heavy metals in thermal conversion systems. The structure was characterized using X-ray pair distribution function analysis, differential scanning calorimetry, and scanning electron microscopy. It was found that the organic additives transformed into porosity during firing. The morphology of the pores also corresponded to the morphology of the organic additives. Hence, the clay ceramic with a 15-wt% addition of biochar had a porosity of 46 vol% with 20-μm interconnected pores after firing. The resulting accumulator was found to capture cadmium (a model for heavy metals with high volatility) via condensation of the cadmium vapor as 2-μm beads in the pores. The cadmium capture efficiency reached up to 57% using a 15-wt% addition of biochar. Furthermore, cadmium was captured at higher temperatures than the condensation temperature in the atmosphere. This means that heavy metals may be captured before they condense in fly ash to promote the recycling of this material

    Ceramic Water Filters for the Removal of Bacterial, Chemical, and Viral Contaminants

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    International audienceIn this study, the combination of capture mechanisms in ceramic water filters (doped with hydroxyapatite and alumina) was considered for the removal of contaminants from drinking water. It was found that hydroxyapatite and alumina were conserved during the firing process of the ceramic water filters up to 950°C. The nanopores resulting from the conservation of the additives increased the specific surface area of the ceramic water filters from 3.7 to 21.0m2·g−1. On the other hand, the microscopic pores associated with the processing of the ceramic water filters (i.e., pressing and drying) and the combustion of the sawdust reduced the filtration time from 24 to 4 h. The efficiency of the resulting filters in removing bacterial, chemical, and viral contaminants from water was investigated using E. coli, fluoride, and MS2 as model contaminants. The contaminants were found to be captured from water by trapping in the pores, substitution in the hydroxyapatite, and adsorption on the surface of alumina. Hence, the ceramic water filters incorporating hydroxyapatite and alumina combined the different capture mechanisms. They had an efficiency of 99.998%, 99.970%, and 99.450% in the removal of bacterial, chemical, and viral contaminants, corresponding to log reduction values (LRVs) of 4.69, 3.47, and 2.26, respectively

    Experimental foundations of chemical engineering

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    Fundamental knowledge consists of understanding not only the models which correlate and rationalized observations but also the quantity and quality of the observations. The degree of correlation attempted should be consistent with this quantity and quality. The scientist correlates and rationalizes observations primarily to broaden his general understanding of the physical universe, and his efforst at correlation are more often than not a way of speculating on the future experiments which should be undertaken to test his concepts. For this purpose he is often satisfied with accuracy to one order of magnitude. The engineer, faced with the design and operation of expensive equipment, is almost always interested in a much higher accuracy in his correlations. Virtually all existing data in the rate processes are forced into rationalizations based upon either potential-difference or potential-gradient models. The application of these models to systems of even relatively simple geometry gives rise to mathematical complexity beyond present analtic ability. Even so, our ability to measure and observe seems to be far below our ability to analyze. These two models have been used effectively in chemical engineering in the past and have served to organize a great deal of information in the rate processes. Present research efforts appear to be directed primarily toward filling in gaps in available data and in refining the application of the models. We seem to suffer from a lack of models to test and a lack of data designed to test critically the existing models. There is relatively little exploratory research in chemical engineering as compared, for example, to physics. When one views chemical engineering as a chain extending from economics, markets, mechanical design, process design, and process development to process research, the uncertainties inherent in some of the links easily involve variances of 50 to 80%. Under these circumstances it would appear that the present orientation of research is distributed much too heavily toward refinement of existing ideas and not nearly enough toward exploration.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37304/1/690050320_ftp.pd

    Making sense of a diagnosis of incurable cancer: The importance of communication

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    Purpose:  Patients diagnosed with incurable cancer may experience existential distressand difficulty in re-appraising their lives because of uncertainty about the future. Objectives: This study sought to understand how patients living with incurable cancer made sense of their diagnosis, how they prepared for the future and what support they wanted from their health professionals.  Subjects:  27 patients were recruited from the oncology and palliative care service at three metropolitan hospitals. Methods:  A qualitative research approach was used. Semi-structured face-to-face interviews were conducted. Interviews were audio-taped and transcribed verbatim.  Data was analyzed using the constant-comparative method.  Results:  Participants did not express a need to make sense of their diagnosis nor always ascribe to a particular religious belief; rather, many relied on a personal spirituality or philosophy to bring meaning to their experience. Importance was placed on their doctor keeping up with technology, being honest, and being confident and positive. Conclusion:  Participants in this study had incurable cancer but making sense of their current situation was not a conscious priority. For these patients, uncertainty was a positive, as certainty for them indicates death is approaching. What these interviews suggest, from the patient’s perspective, is that there is an implied contract between doctor and patient during this period which involves the doctor managing the flow of difficult information so that the patient can maintain normality for as long as possible. Understanding this helps to explain the difficulty of having advance care planning conversations within this setting, despite the many opportunities that a longer disease trajectory would seem to offer.

    Simultaneous X-ray and radio observations of Young Stellar Objects in NGC 1333 and IC 348

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    Young Stellar Objects (YSOs) and in particular protostars are known to show a variety of high-energy processes. Observations in the X-ray and centimetric radio wavelength ranges are thought to constrain some of these processes, e.g., coronal-type magnetic activity. There is a well-known empirical correlation of radio and X-ray luminosities in active stars, the so-called Guedel-Benz relation. Previous evidence whether YSOs are compatible with this relation remains inconclusive for the earliest evolutionary stages. The main difficulty is that due to the extreme variability of these sources, simultaneous observations are essential. Until now, only few YSOs and only a handful of protostars have been observed simultaneously in the X-ray and radio range. To expand the sample, we have obtained such observations of two young clusters rich in protostars, NGC 1333 and IC 348. While the absolute sensitivity is lower for these regions than for more nearby clusters like CrA, we find that even in deep continuum observations carried out with the NRAO Very Large Array, the radio detection fraction for protostars in these clusters is much lower than the X-ray detection fraction. Very few YSOs are detected in both bands, and we find the radio and X-ray populations among YSOs to be largely distinct. We combine these new results with previous simultaneous Chandra and VLA observations of star-forming regions and find that YSOs with detections in both bands appear to be offset toward higher radio luminosities for given X-ray luminosities when compared to the Guedel-Benz relation, although even in this sensitive dataset most sources are too weak for the radio detections to provide information on the emission processes. The considerably improved sensitivity of the Expanded Very Large Array will provide a better census of the YSO radio population as well as better constraints on the emission mechanisms.Comment: Accepted for publication in Ap

    Magnetron priming by multiple cathodes

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    A relativistic magnetron priming technique using multiple cathodes is simulated with a three-dimensional, fully electromagnetic, particle-in-cell code. This technique is based on electron emission from N/2N∕2 individual cathodes in an NN-cavity magnetron to prime the ππ mode. In the case of the six-cavity relativistic magnetron, ππ-mode start-oscillation times are reduced up to a factor of 4, and mode competition is suppressed. Most significantly, the highest microwave field power is observed by utilizing three cathodes compared to other recently explored priming techniques.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87840/2/081501_1.pd
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