Survey of Material for an Infrared-Opaque Coating

More than 40 reflectance spectra in the range from 20 to 500 microns have been obtained for a variety of coatings, binders, and additives to identify promising components of an infrared-opaque coating for the Space Infrared Telescope Facility. Certain combinations of materials showed a specular reflectance below 0.1 throughout the spectral range measured. In addition to estimating the optical constants of several combination coatings, this survey also supports three qualitative conclusions: (1) promising off-the-shelf binders of different additives are Chemglaze Z-306, ECP-2200, and De Soto Black; (2) carbon black is very effective in reducing far-infrared reflectance; (3) the far-infrared reflectance from coatings containing 80 SiC grit is consistently lower than that from similar coatings containing TiBr powder

Life and reliability of rotating disks

In aerospace applications, an engineer must be especially cognizant of size and weight constraints which affect design decisions. Although designing at or below the material fatigue limit may be desirable in most industrial applications, in aerospace application it is almost mandatory to design certain components for a finite life at an acceptable probability of survival. Zaretsky outlined such a methodology based in part on the work of W. Weibull (1939, 1951) and G. Lundberg and A. Palmgren (1947a, 1947b, 1952). It is the objective of this work to apply the method of Zaretsky (1987) to statistically predict the life of a generic solid disk with and without bolt holes; determine the effect of disk design variables, thermal loads, and speed on relative life; and develop a generalized equation for determining disk life by incorporating only these variables

Development and validation of the child post-traumatic cognitions inventory (CPTCI)

Background: Negative trauma-related cognitions have been found to be a significant factor in the maintenance of post-traumatic stress disorder (PTSD) in adults. Initial studies of such appraisals in trauma-exposed children and adolescents suggest that this is an important line of research in youth, yet empirically validated measures for use with younger populations are lacking. A measure of negative trauma-related cognitions for use with children and adolescents, the Child Post-Traumatic Cognitions Inventory (CPTCI), is presented. The measure was devised as an age-appropriate version of the adult Post-Traumatic Cognitions Inventory (Foa et al., 1999). Methods: The CPTCI was developed and validated within a large (n = 570) sample, comprising community and trauma-exposed samples of children and adolescents aged 6-18 years. Results: Principal components analysis suggested a two-component structure. These components were labelled 'permanent and disturbing change' and 'fragile person in a scary world', and were each found to possess good internal consistency, test-retest reliability, convergent validity, and discriminative validity. The reliability and validity of these sub-scales was present regardless of whether the measure was completed in the acute phase or several months after a trauma. Scores on these sub-scales did not vary with age. Conclusions: The CPTCI is a reliable and valid measure that is not specific to the type of trauma exposure, and shows considerable promise as a research and clinical tool. The structure of this measure suggests that appraisals concerning the more abstract consequences of a trauma, as well as physical threat and vulnerability, are pertinent factors in trauma-exposed children and adolescents, even prepubescent children

Some Implications of Outdoor Recreation Desires for Urban Redevelopment

Author Institution: Department of Geography, Miami UniversityThe significance of four attributes of outdoor recreation relative to a consideration of urban redevelopment forms the focus of this paper. Data on the public's desires for specific recreational facility qualities and activities and the socio-economic characteristics of households are used to develop implications for urban redevelopment policy. Some effects of household income level, car availability, and place of residence are examined as examples. Conclusions are based on a possible set of public responses and emphasize the need for a fuller appreciation of the role of outdoor recreation in policy determination

Pilot Knob Bog as a Habitat

The purposes of this paper are to introduce some of the physical characteristics and to summarize the geological and recent history of a northern Iowa Sphagnum bog. The marshy portion of Dead Man\u27s Lake, Pilot Knob State Park, was referred to as a bog by L. H. Pammel (1928) and described as a sphagnum mat by Grant and Thorne (1954). The park is located on the Hancock side of the Hancock-Winnebago county border in sections three and four of Ellington township. It is four miles east of Forest City

DIRECT ESTIMATION OF ABOVEGROUND FOREST PRODUCTIVITY THROUGH HYPERSPECTRAL REMOTE SENSING OF CANOPY NITROGEN

The concentration of nitrogen in foliage has been related to rates of net photosynthesis across a wide range of plant species and functional groups and thus represents a simple and biologically meaningful link between terrestrial cycles of carbon and nitrogen. Although foliar N is used by ecosystem models to predict rates of leaf‐level photosynthesis, it has rarely been examined as a direct scalar to stand‐level carbon gain. Establishment of such relationships would greatly simplify the nature of forest C and N linkages, enhancing our ability to derive estimates of forest productivity at landscape to regional scales. Here, we report on a highly predictive relationship between whole‐canopy nitrogen concentration and aboveground forest productivity in diverse forested stands of varying age and species composition across the 360 000‐ha White Mountain National Forest, New Hampshire, USA. We also demonstrate that hyperspectral remote sensing can be used to estimate foliar N concentration, and hence forest production across a large number of contiguous images. Together these data suggest that canopy‐level N concentration is an important correlate of productivity in these forested systems, and that imaging spectrometry of canopy N can provide direct estimates of forest productivity across large landscapes

Studies of angle-resolved photoelectron spectra from oriented NiCO: A model for adsorbed CO

We present a study of angle-resolved photoelectron spectra from oriented, linear NiCO. We address the question: How well do simple cluster models such as oriented NiCO simulate adsorbate molecules with respect to photoemission? The photoemission cross sections are obtained using Hartree-Fock electronic continuum orbitals. For the bonding 5σ̃ orbital, we find oriented NiCO to be a better model than oriented CO. The large magnitude of the 5σ̃ photoionization cross sections relative to the 4σ̃ cross section cannot, however, be explained by our calculations without consideration of backscattering of the photoelectrons ejected "downward" into the detector

Analysis of employment conditions for full-time hired farm labor on eastern Iowa hog farms

American agriculture has been and continues to be an industry with a changing structure. The amount of farm labor declined steadily over the 1950-1970 period as competitive forces in farming resulted in capital being substituted for labor and land. One factor in this decline has been the increased productivity resulting from technological improvements in capital inputs and the greater know how” in the use of these inputs. A second factor has been the decline in prices of capital inputs relative to the prices of land and labor. As farms have become larger and more capitalized, decision making has become more complex. The level of skill needed by farm labor also has increased as the size of enterprises and the complexities of equipment have increased. This study examines the employment conditions of full-time hired farm labor in an effort to resolve a farm-labor paradox. The paradox results from full-time job positions in farming going unfilled in the late 1960s, at a time when labor was being freed” from farming as a result of the decline in farm numbers and the substitution of capital for labor

Referendum Design and Contingent Valuation: The NOAA Panel's No-Vote Recommendation

In 1992 the National Oceanic and Atmospheric Administration (NOAA) convened a panel of prominent social scientists to assess the reliability of natural resource damage estimates derived from contingent valuation (CV). The product of the Panel's deliberations was a report that laid out a set of recommended guidelines for CV survey design, administration, and data analysis. One of the Panel's recommendations was that CV surveys should employ a referendum approach. This method describes a choice mechanism that asks each respondent how they would vote if faced with a particular program and the prospect of paying for the program through some means, such as higher taxes. The Panel also recommended that CV referendum questions which commonly use only "for" or "against" answers should be expanded to explicitly offer an "I would-not-vote" response. The purpose of this paper is to consider the effects of such a "would-not-vote" option. In developing the test, we followed the important elements of the NOAA Panel guidelines for the design and administration of a CV survey and use what was acknowledged(by the Panel) as the most carefully developed CV questionnaire to that time, that is, the State of Alaska's study of the Exxon Valdez oil spill. Our findings suggest that when those selecting the "would-not-vote" response are treated as having voted "against" the offered program, offering the option does not alter: (a) the distribution of "for" and "against" responses, (b) the estimates of WTP derived from these choices, or (c) the construct validity of the results.

Temporal Reliability of Estimates from Contingent Valuation

In 1992 the National Oceanic and Atmospheric Administration (NOAA) convened a panel of prominent social scientists to assess the reliability of natural resource damage estimates derived from contingent valuation (CV). The product of the panel's deliberations was a report that laid out a set of recommended guidelines for CV survey design, administration, and data analysis. This paper focuses on one of these guidelines�the Panel's call for the "temporal averaging" of willingness-to-pay (WTP) responses obtained from CV surveys as one method for increasing their reliability. The panel suggested: "Time dependent measurement noise should be reduced by averaging across independently drawn samples taken at different points in time. A clear and substantial time trend in the responses would cast doubt on the 'reliability' of the finding." The purpose of this paper is to examine the temporal reliability of CV estimates. Our findings, using a CV instrument designed to measure willingness-to-pay for a program to protect Prince William Sound, Alaska from future oil spills, like the Exxon Valdez spill, exhibited no significant sensitivity to the timing of the interviews. For two samples involving independent interviews taken over two years apart, the distribution of respondents' choices "for" and "against" the protection program did not differ.