54 research outputs found
Mineralogy and composition of Archean Crust, Greenland: A pilot study
The Portable Instant Display and Analysis Spectrometer (PIDAS) was taken to southwestern Greenland to investigate in situ the potential application of AVIRIS to estimate the mineralogy and composition of rocks exposed in Archean terranes. The goal was to determine the feasibility of using a high spectral resolution scanner to find and study pristine rocks, those that have not been altered by subsequent deformation and metamorphism. The application of AVIRIS data to the problems in Greenland is logical. However, before a costly deployment of the U-2 aircraft to Greenland is proposed, this study was undertaken to acquire the spectral data necessary to verify that mineralogical mapping in the environmental conditions found there is possible. Although field conditions were far from favorable, all of the major objectives of the study were addressed. One of the major concerns was that lichens would obscure the rock surfaces. It was found that the spectral signature of the lichens was distinct from the underlying rocks. Thus, a spectrum of a rock outcrop, with its partial cover of lichens, can be un-mixed into rock and lichen components. The data acquired during the course of this study supports the conclusion that areas of pristine Archean crust can be differentiated from that which has experienced low grade alteration associated with Proterizoic faulting
A tool for manual endmember selection and spectral unmixing
Sampling a continuous radiance spectrum in many narrow contiguous spectral bands results in a high covariance between the bands. Hence, the true dimensionality of imaging spectrometer data is not determined by the number of spectral bands, but by the number of spectrally unique signatures whose mixtures reproduce the spectral variance observed in an image. Methods to unmix high dimensional multispectral data use principal components analysis to reduce the dimensionality. The variance of the spectral data is modeled as a linear combination of a finite set of endmembers in the space of the eigen-vectors that account for most of the variance. The number and characteristics of these endmembers are determined not only by the number and characteristics of the spectrally unique materials on the surface but also by processes (e.g., illumination, atmospheric scattering and absorption) affecting the signal received by the sensor. Selection of endmember spectra has typically been from a library. However, since most libraries are incomplete and do not account for the processes mentioned above, we have devised a computer display that allows researchers to explore interactively the eigenvector space of a representative and mean-corrected subset of the image data in search of extreme spectra to designate as endmembers. This display, which is based on parallel coordinates, is unique in the area of multidimensional visualization in that it includes not only a passive view of higher dimensional data but also the capability to interact and move geometrical objects in higher dimensional spaces
A comparison of spectral mixture analysis an NDVI for ascertaining ecological variables
In this study, we compare the performance of spectral mixture analysis to the Normalized Difference Vegetation Index (NDVI) in detecting change in a grassland across topographically-induced nutrient gradients and different management schemes. The Konza Prairie Research Natural Area, Kansas, is a relatively homogeneous tallgrass prairie in which change in vegetation productivity occurs with respect to topographic positions in each watershed. The area is the site of long-term studies of the influence of fire and grazing on tallgrass production and was the site of the First ISLSCP (International Satellite Land Surface Climatology Project) Field Experiment (FIFE) from 1987 to 1989. Vegetation indices such as NDVI are commonly used with imagery collected in few (less than 10) spectral bands. However, the use of only two bands (e.g. NDVI) does not adequately account for the complex of signals making up most surface reflectance. Influences from background spectral variation and spatial heterogeneity may confound the direct relationship with biological or biophysical variables. High dimensional multispectral data allows for the application position of techniques such as derivative analysis and spectral curve fitting, thereby increasing the probability of successfully modeling the reflectance from mixed surfaces. The higher number of bands permits unmixing of a greater number of surface components, separating the vegetation signal for further analyses relevant to biological variables
Formulation, Casting, and Evaluation of Paraffin-Based Solid Fuels Containing Energetic and Novel Additives for Hybrid Rockets
This investigation studied the inclusion of various additives to paraffin wax for use in a hybrid rocket motor. Some of the paraffin-based fuels were doped with various percentages of LiAlH4 (up to 10%). Addition of LiAlH4 at 10% was found to increase regression rates between 7 - 10% over baseline paraffin through tests in a gaseous oxygen hybrid rocket motor. Mass burn rates for paraffin grains with 10% LiAlH4 were also higher than those of the baseline paraffin. RDX was also cast into a paraffin sample via a novel casting process which involved dissolving RDX into dimethylformamide (DMF) solvent and then drawing a vacuum on the mixture of paraffin and RDX/DMF in order to evaporate out the DMF. It was found that although all DMF was removed, the process was not conducive to generating small RDX particles. The slow boiling generated an inhomogeneous mixture of paraffin and RDX. It is likely that superheating the DMF to cause rapid boiling would likely reduce RDX particle sizes. In addition to paraffin/LiAlH4 grains, multi-walled carbon nanotubes (MWNT) were cast in paraffin for testing in a hybrid rocket motor, and assorted samples containing a range of MWNT percentages in paraffin were imaged using SEM. The fuel samples showed good distribution of MWNT in the paraffin matrix, but the MWNT were often agglomerated, indicating that a change to the sonication and mixing processes were required to achieve better uniformity and debundled MWNT. Fuel grains with MWNT fuel grains had slightly lower regression rate, likely due to the increased thermal conductivity to the fuel subsurface, reducing the burning surface temperature
SdiA, an N-Acylhomoserine Lactone Receptor, Becomes Active during the Transit of Salmonella enterica through the Gastrointestinal Tract of Turtles
encode a LuxR-type AHL receptor, SdiA, they cannot synthesize AHLs. In vitro, it is known that SdiA can detect AHLs produced by other bacterial species..We conclude that the normal gastrointestinal microbiota of most animal species do not produce AHLs of the correct type, in an appropriate location, or in sufficient quantities to activate SdiA. However, the results obtained with turtles represent the first demonstration of SdiA activity in animals
Integrated measurements of acoustical and optical thin layers II: Horizontal length scales
Gender and Right-Wing Authoritarianism in a working-class case-study
Objective: In this article we attempt to shed light on the changing attitudes American workers may have, specifically authoritarian personality characteristics, by reviewing the results obtained from our survey of 74 retired auto workers.
Research Design & Methods: Part of our survey utilizes the Zakrisson short version of the Right-Wing Authoritarian scale and our interests are to provide any differences found between men and women. Also, we seek to test for the presence of authoritarianism as one aspect to understand the appeal of right-wing politics among the white working class.
Findings: Our findings indicate that men and women are each no more or less likely to develop authoritarian personality characteristics. The differences by gender that we found in our case-study mirror the literature over the last several decades since empirical research began in 1950 – ambivalence.
Implications/Recommendations: As a discontented citizenry searches for answers, by leaning more politically right or left will gender differences widen or converge due to the issues.
Contribution/Value Added: Given the current social and economic climate in the United States we find this research study to be both timely and important. A conservative or liberal orientation by American workers may have important contributions for the direction the US takes not only on pressing economic and social issues at home but abroad as well
Minority Status and Workers Commitment to Their Union: Liberal versus Conservative
In our study of attitudes among industrial workers at a plant in the United States, the analysis reveals differences between white males on one side, and women and minorities on the other side. Specifically, the survey question targeted was In order to succeed, my union should work with outside groups such as civil rights and environmental groups. In efforts to ascertain this information, data was collected on two surveys that were administered to a major industrial union of 1,640 workers, one in 2004 and another in 2007. The results follow similar findings in other studies that white males specifically, and whites in general in the working class are diverging in social attitudes compared to their minority and female coworkers. Generally, women and minorities are becoming consistently liberal, while white males in particular are becoming consistently conservative. This has significant ramifications for organized labor, labor politics and wider gender relations
General Chemistry Laboratory Experiment To Demonstrate Organic Synthesis, Fluorescence, and Chemiluminescence Through Production of a Biphasic Glow Stick
A laboratory experiment is described for beginning, nonmajor chemistry students, which allows students to examine the phenomena of fluorescence and chemiluminescence, as well as gain experience in basic organic synthesis. Students synthesize fluorescein and bis(2,4,6-trichlorophenyl) oxalate (TCPO) to explore fluorescence and chemiluminescence by assembling a biphasic glow stick. The experiment gives students the opportunity to understand the chemistry behind common “real-life” experiences of glow stick illumination and fluorescent lighting or inks and to synthesize compounds that exhibit these phenomena. Students’ survey data between 2013 and 2016 show that the experiment was enjoyable to undergraduate nonscience majors (4.3 of 5 cumulative, 4.8 in 2016) and relevant to their lives (4.0 of 5 cumulative, 4.4 in 2016)
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