Showing papers by "Brigham Young University published in 1993"
Book•
01 Jan 19932,013 citations
TL;DR: In this paper, a new microscopy called orientation imaging microscopy is described, which is based on precise measurements of local lattice orientation facilitated by backscattered Kikuchi diffraction.
Abstract: A new microscopy, called orientation imaging microscopy, is described. Imaging results from precise measurements of local lattice orientation facilitated by backscattered Kikuchi diffraction. The hardware configuration of the microscope is described, and a formal description of image formation is developed. Application of the method to several cubic materials and material conditions is described. Emphasis is given to those areas of application where new insight into polycrystalline microstructures has begun to emerge.
851 citations
TL;DR: The authors examined the effect of real activity news on proxies for expected cash flows and equity discount rates and found that when the economy is strong the stock market responds negatively to news about higher real economic activity.
Abstract: Previous research finds that fundamental macroeconomic news has little effect on stock prices. We show that after allowing for different stages of the business cycle, a stronger relationship between stock prices and news is evident. In addition to stock prices, we examine the effect of real activity news on proxies for expected cash flows and equity discount rates. We find that when the economy is strong the stock market responds negatively to news about higher real economic activity. This negative relation is caused by the larger increase in discount rates relative to expected cash flows. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.
568 citations
TL;DR: In this paper, an approach for generating weighted-sum-of-gray gases (WSGG) models directly from the line-by-line spectra of H[sub 2]O was presented.
Abstract: This paper presents an approach for generating weighted-sum-of-gray gases (WSGG) models directly from the line-by-line spectra of H[sub 2]O. Emphasis is placed on obtaining detailed spectral division among the gray gases. Thus, for a given model spectrum, the gray gas weights are determined as blackbody fractional functions for specific subline spectral regions at all temperatures. The model allows the absorption coefficient to be the basic radiative property rather than a transmissivity or band absorptance, etc., and can be used with any arbitrary solution method for the Radiative Transfer Equation (RTE). A single absorption cross section spectrum is assumed over the entire spatial domain in order to fix the subline spectral regions associated with a single spectral calculation. The error associated with this assumption is evaluated by comparison with line-by-line benchmarks for problems of nonisothermal and nonhomogeneous media. 28 refs., 7 figs.
379 citations
374 citations
TL;DR: In coal pyrolysis, a number of new experimental and theoretical approaches have been proposed to shed new light on the subject as mentioned in this paper, such as kinetics, the formation of volatile products, network models, cross-linking, rank effects, and the two-component model of coal structure.
305 citations
TL;DR: In this paper, the authors explored the variables and patterns gathered from their interviews and found that the resiliency themes extracted included: the ability to find emotional support outside the family; self-regard or self-think well of oneself; spirituality; external attribution of blame and cognitive style; and inner-directed locus of control.
Abstract: The 22 women interviewed in this study were in a high-risk group for low self-esteem, depression, shame, and other long-term interpersonal difficulties due to their survival of childhood sexual abuse. Unlike many of their contemporaries, they have been able to have relationships, stable careers, and healthy personalities. This paper explores the variables and patterns gathered from their interviews. The resiliency themes extracted included: the ability to find emotional support outside the family; self-regard or the ability to think well of oneself; spirituality; external attribution of blame and cognitive style; and inner-directed locus of control.
290 citations
TL;DR: A questionnaire measure of kindergarten teachers' beliefs and practices based on the guidelines for developmentally appropriate practice of the National Association for the Education of Young Children was administered, and the results provide support that the instruments developed hold promise for utilization in future research on kindergarten teachers'?
285 citations
01 Sep 1993
TL;DR: The algorithm produces shape blends which generally are more satisfactory than those produced using linear or cubic curve paths, and can avoid the shrinkage that normally occurs when rotating rigid bodies are linearly blended.
Abstract: This paper presents an algorithmfor determiningthe paths along which corresponding vertices travel in a 2–D shape blending. Rather than considering the vertex paths explicitly, the algorithm defines the intermediate shapes by interpolating the intrinsic definitions of the initial and final shapes. The algorithm produces shape blends which generally are more satisfactory than those produced using linear or cubic curve paths. Particularly, the algorithm can avoid the shrinkage that normally occurs when rotating rigid bodies are linearly blended, and avoids kinks in the blend when there were none in the key polygons.
276 citations
TL;DR: A method for generating enhanced resolution radar images of the Earth's surface using spaceborne scatterometry using an image reconstruction technique that takes advantage of the spatial overlap in scatterometer measurements made at different times to provide enhanced imaging resolution is presented.
Abstract: A method for generating enhanced resolution radar images of the Earth's surface using spaceborne scatterometry is presented. The technique is based on an image reconstruction technique that takes advantage of the spatial overlap in scatterometer measurements made at different times to provide enhanced imaging resolution. The reconstruction algorithm is described, and the technique is demonstrated using both simulated and actual Seasat-A Scatterometer (SASS) measurements. The technique can also be used with ERS-1 scatterometer data. The SASS-derived images, which have approximately 4-km resolution, illustrate the resolution enhancement capability of the technique, which permits utilization of both historic and contemporary scatterometer data for medium-scale monitoring of vegetation and polar ice. The tradeoff between imaging noise and resolution inherent in the technique is discussed. >
274 citations
TL;DR: In this paper, a review of the literature related to the Rijke tube is presented, with a focus on the manner in which the oscillating response of the heat source is modeled, from simple phenomenological models to sophisticated models based on activation energy asymptotic theory.
TL;DR: In this article, the loss of semi-volatile organic compounds from particles collected with a filter is measured by comparing the amounts collected by comparable filter pack and diffusion denuder samplers.
TL;DR: In this paper, a broad treatment of the technology and the science related to fixed-bed coal combustion and gasification is provided, including countercurrent, cocurrent, and crosscurrent configurations.
TL;DR: In this paper, the problem of extending the estimation of signal parameters via rotational invariance techniques (ESPRIT) algorithm for multiple source, cochannel direction finding to the two-dimensional case (e.g., azimuth and elevation angle estimation) was considered.
Abstract: The authors consider the problem of extending the estimation of signal parameters via rotational invariance techniques (ESPRIT) algorithm for multiple source, cochannel direction finding to the two-dimensional case (e.g., azimuth and elevation angle estimation). Two algorithms are presented, one based on the optimal (minimal variance) subspace fitting formulation of ESPRIT, and the other based on an approximation to it. The algorithms are applicable to antenna arrays composed of identical subarrays displaced in two dimensions, such as uniform rectangular phased arrays. Simulation results illustrating the relative performance of the algorithms are also presented. >
TL;DR: The iIntegrated Product and Process Design (iP&P) course as discussed by the authors is a course focused on industrial design and manufacturing projects, which involves both product and process design activities.
Abstract: It is sometimes forgotten that industry is an important customer of engineering education. Ignoring this relationship has produced graduates that often fail to meet the changing needs of industry in todayis competitive environment. On the basis of feedback from our industrial customers, faculty from Mechanical Engineering and Manufacturing Engineering at Brigham Young University have jointly developed a new senior capstone design course entitled iIntegrated Product and Process Design.i This new capstone course is centered on industrial design and manufacturing projects. These projects involve both product and process design activities. Multidisciplinary teams of students are taught a structured development approach to produce typical industrial deliverables. These deliverables include a functional specification, product and process design, prototype, and first production sample. This paper identifies changing industrial needs, describes how the course was designed to meet these needs, and presents results from the initial offerings of the course.
TL;DR: In this paper, the authors examine a method for the application of learning style theory to engineering education and examine specific objectives for each of the four learning quadrants, each of which is associated with a particular learning style or preference.
Abstract: The purpose of this paper is to examine a method for the application of learning style theory to engineering education. Research has shown that students learn in a variety of different ways, and that each student has a preferred style of learning. Teaching effectiveness may be enhanced by teaching to each of the preferred styles at least a portion of the time. The application of learning style theory in this paper is based on the work of Kolb who identified four principal learning styles or types. The process of teaching to each of the four learning styles is referred to as “teaching through the cycle.” The learning cycle consists of four quadrants, each of which is associated with a particular learning style or preference. This paper defines specific objectives for each of the four learning quadrants. In addition, activities which can be used to accomplish these objectives are presented and discussed. Sample lesson plans have also been included in order to illustrate application of the learning cycle to the teaching of specific engineering topics.
TL;DR: It is concluded that in current smokers PM10 possibly has a small transient negative effect on lung function that is not entirely obscured by their smoking habit.
Abstract: This study assessed the association between respirable particulate air pollution (PM10) and changes in the pulmonary function (FEV1, FEV1/FVC, and FVC) of smokers with mild to moderate airflow limitation. Spirometric data of Salt Lake City participants in The Lung Health Study were used from two screening visits 10 to 90 days apart after an initial screening visit, which included spirometry. We analyzed differences in pulmonary function (ΔFEV1, ΔFEV1/FVC, and ΔFVC) for participants between the two spirometry visits. Significant associations between changes in pulmonary function and PM10 were observed. ΔFEV1 and ΔFEV1/FVC were inversely associated with changes in PM10. Although these associations were small, explaining only about 2 to 3% of the variance in ΔFEV1, they were consistently negative and statistically significant (p ⩽ 0.01). On average, an increase in PM10 equal to 100 µg/m3 was associated with a marginal decline in FEV1 equal to approximately 2%. Associations between AFVC and PM10 were consiste...
TL;DR: In this article, the authors present evidence that business cycles are characterized by sharp troughs and round peaks, and they suggest caution in interpreting empirical tests of economic series that assume symmetry and motivate theoretic models in which additions to capacity, production and employment at the end of a recession are not mirror images of the cutbacks at the beginning of an expansion.
TL;DR: In this article, the effects of atmosphere, time, temperature, support, promoters, and metal on the thermal stability of supported metal catalysts were investigated. But the analysis of these data was restricted to the case of supported metals.
Abstract: Studies of sintering kinetics of conventional supported metal catalysts are reviewed. Available kinetic data for sintering have been reanalyzed using the new General Power Law Expression (GPLE), which provides the capability of treating these data in a consistent, unifying fashion such that quantitative comparisons regarding effects of reaction conditions and catalyst properties are possible for the first time. It is shown that all available dispersion-versus-time data can be fitted to either first or second order GPL kinetics. From the analysis of these data new conclusions arise regarding the effects of atmosphere, time, temperature, support, promoters, and metal on the thermal stability of supported metals.
TL;DR: A completely automated system which couples automatic analysis of electron backscatter diffraction diffraction patterns (EBSPs) with precise movement of the sample in the SEM is described and the Hough transform approach to correctly identify diffraction bands is quantitatively compared with the Burns algorithm.
Abstract: A completely automated system which couples automatic analysis of electron backscatter diffraction
patterns (EBSPs) with precise movement of the sample in the SEM is described. The Hough
transform is implemented into an existing technique for identifying lattice orientation through
automatic analysis of EBSPs. The ability of the Hough transform approach to correctly identify
diffraction bands is quantitatively compared with the Burns algorithm. Both methods were tested on
1000 EBSPs from well annealed oxygen-free, electrical grade (OFE) copper, 120 patterns from as-cast
commercially pure aluminum and 106 patterns from 40% channel-die compressed aluminum. Only
slight differences were found in the ability of the methods to correctly identify bands in the sample
EBSPs. The three test runs resulted in 95-99% (OFE Cu), 97.5-99% (as-cast AI) and 81-85%
(deformed AI) correctly determined orientations (less than 5° off the manually determined reference
orientations). The limits in the ability of the band detection algorithms to fix the bands exactly are
discussed. To obtain the orientation which satisfies the detected bands most completely, a method of
averaging solutions obtained from different triplets of bands is introduced.
TL;DR: In this paper, an absorption-line blackbody distribution function for H2O is presented, which provides an efficient means for total radiative transfer calculations by eliminating the need to specify a path-length required by current narrow and wide band models.
Abstract: An absorption-line blackbody distribution function for H2O which provides an efficient means for total radiative transfer calculations is presented. The function eliminates the need to specify a path-length required by current narrow and wide band models since the basic radiative property is the locally defined absorption coefficient. This allows the model to be used with arbitrary solution methods of the radiative transfer equation which requires the absorption coefficient as input. A simple mathematical correlation is presented for use in computer algorithms. A few sample calculations of total emissivity as well as numerical solutions to the radiative transfer equation with the use of the distribution function are performed. The model shows good agreement with Hottel's total emissivity data. There is also very good agreement between the model and computationally intensive line-by-line calculations in isothermal media of uniform composition. The function may also be used for approximate calculations in non-uniform media.
Journal Article•
TL;DR: There is evidence that associated animals may be nutritionally benefited by the enhanced mineral content of forage plants growing in well-developed cyanobacterial crusts.
Abstract: In both field and greenhouse studies, cyanobacterial and cyanolichens of cold-temperature deserts often enhance growth and essential uptake by associated herbs. That effect is associated with better seedling establishment and larger seedlings. The following are possible mechanisms for these effects: (1) the microbiota concentrate essential elements in available forms in soil surface layers, (2) the microbial surface covers are usually darker colored than the soil itself and produce warmer soils during cool seasons when soil water is most available, (3) the gelatinous sheaths of several cyanobacterial genera common on alkaline deserts contain chelating compounds, and (4) conditions that favor persistent microbial growths on soil surfaces also favor maintenance of larger populations of microorganisms that form mycorrhizal and/or rhizosheath associations with seed plants. There is evidence that associated animals may be nutritionally benefited by the enhanced mineral content of forage plants growing in well-developed cyanobacterial crusts.
TL;DR: In this article, transcriptional activation of the prostaglandin G/H synthase isoenzyme 2 (PGHS-2) gene is shown to be responsible for this induction.
TL;DR: In this paper, the authors argue that the traditional social science goals of "prediction" and "control" of systems behavior are sometimes, if not usually, unobtainable.
Abstract: Based on theoretical and mathematical principles of chaos theory, we argue that the customary social science goals of "prediction" and "control" of systems behavior are sometimes, if not usually, unobtainable. Specifically, chaos theory shows how it is possible for nearly identical entities embedded in identical environments to exhibit radically different behaviors, even when the underlying systems are extremely simple and completely deterministic. Furthermore, chaos theory arguments are general enough to apply to any type of entity, including individuals, groups, and organizations, and therefore they are relevant to a large domain of social science problems. As a result, this paper concludes with six familiar claims about the study of social phenomena for which chaos theory provides new theoretical arguments.
TL;DR: A mesh smoothing technique that uses optimization principles to minimize a distortion metric throughout a mesh is presented and comparison is made with laplacian and isoparametric smoothing techniques.
TL;DR: Analysis of hamster/mouse somatic cell hybrids with radiolabeled cDNA probes demonstrated that PGHS-1 mapped to chromosome 2 andPGHS-2 mapped to chromosomes 1 of the mouse genome, suggesting that dexamethasone may inhibit PG HS-2 mRNA expression at the post-transcriptional level.
TL;DR: In this paper, the developmental implications for fathers of their underinvolvement in child care using Erikson's conception of adult development and his emphasis on achieving generativity are explored.
Abstract: Most studies of fathers' participation in child care focus on fairness, or domestic democracy. What is sacrificed by fairness-focused studies of family work is attention to the developmental tasks that adult men and women face while building a life together. This article explores the developmental implications for fathers of their underinvolvement in child care using Erikson's conception of adult development and his emphasis on achieving generativity. We suggest processes by which fathers may develop generativity and outline the challenges they face in achieving it. The transition to parenthood often sets mothers and fathers on divergent developmental trajectories that may leave them in different developmental positions. Men's involvement in child care may be crucial to keeping men's and women's development synchronous and hence to maintaining satisfying relationships. A developmental perspective on men's participation in child care may also be more conducive to helping fathers increase their involvement ...
TL;DR: In this article, the performance of the MUSIC algorithms for narrowband direction-of-arrival (DOA) estimation when the array manifold and noise covariance are not correctly modeled was investigated, and extended to multidimensional subspace-based algorithms including deterministic (or conditional) maximum likelihood, MD-MUSIC, weighted subspace fitting (WSF), MODE, and ESPRIT.
Abstract: For pt.I, see ibid., vol.40, no.7, p.1758-74 (1992). In pt.I the performance of the MUSIC algorithms for narrowband direction-of-arrival (DOA) estimation when the array manifold and noise covariance are not correctly modeled was investigated. This analysis is extended to multidimensional subspace-based algorithms including deterministic (or conditional) maximum likelihood, MD-MUSIC, weighted subspace fitting (WSF), MODE, and ESPRIT. A general expression for the variance of the DOA estimates that can be applied to any of the above algorithms and to any of a wide variety of scenarios is presented. Optimally weighted subspace fitting algorithms are presented for special cases involving random unstructured errors of the array manifold and noise covariance. It is shown that one-dimensional MUSIC outperforms all of the above multidimensional algorithms for random angle-independent array perturbations. >
TL;DR: In this article, it was shown that this procedure is inefficient when multiple constrained resources exist and that linear-integer programming is a much better planning tool and comes closder to achieving the TOC goal of maximizing throughput.