69 research outputs found
An IAM Theory for Internal Rotation in Completely Asymmetric Molecules. Application to the Analysis of the Microwave Spectra of and .
No full text Microwave detection of direct trans to gauche transitions in . C. F. Su and C. R. Quade. (To appear in J. Mol. Spec. spring '89). Microwave detection of direct gauche to trans transitions in . C. F. Su and C. R. Quade, J. Chem. Phys. 90, 1396(1989). P. Venkateswarlu and H. Gordy, J. Chem. Phys. 32, 1200(1955).Author Institution: Department of Physics, Texas Tech UniversityAn IAM theory has been developed for application in the spectral analysis of and . Torsion-rotation term values are calculated with first principles from the molecular structure in single degree of internal freedom model. A modified V and G structure gives the best fit to the data, even improving upon the phenomonological approach reported with the However, it is clear from the spectral fit that vibration-rotation-internal rotation interactions are also important
-DEPENDENCE OF THE VIBRATIONAL ZEROPOINT ENERGY IN THE PARTIALLY DEUTERATED METHYL ALCOHOLS, REVISITED
No full text1. A Serrallach, R. Mever, and Hs. H. Gunthard, J. Mol. Spec. 52, 94(1974). 2. C. R. Quade and R. D. Suenram, J. Chem. Phys. 73, 1127(1980): 81, 1054(1984).Author Institution: Department of Physics, Texas Tech UniversityThe contribution of the zeropoint energy from the 3N - 7 other vibrations to the effective potential energy for internal rotation have been calculated for eight isotopic species of methyl alcohol. The basis of the calculation is the set of force constants determined by Serrallach, Meyer, and from infrared analyses. The calculated results for are and with . These values agree favorably with the experimental results as previously determined by Quade and from analysis of the microwave torsional-rotational spectra of
EXTENSION OF THE CURVILINEAR INTERNAL COORDINATE FORMULATION OF THE VIBRATION--ROTATION TO HIGHER ORDER
No full textC.R. Quade, J. Chem. Phys., vol. 64, 2783 (1976).Author Institution:The connection between rotation vectors and angular velocity is used to extend the curvilinear internal coordinate formulation of vibration-rotation dynamics to higher orders in the rotation vector , which is determined by the equilibrium inertial tensor , the equilibrium Coriolis coupling matrix , and internal coordinates . Third and higher order terms of the rotated ineritial tensor and second and higher order terms of the rotated Coriolis coupling matrix are presented and discussed
CONTRIBUTIONS OF THE INTERACTION OF INTERNAL ROTATION WITH OTHER VIBRATIONS TO THE EFFECTIVE POTENTIAL ENERGY FOR INTERNAL ROTATION IN MOLECULES
No full text C. R. Quade, J. Chem. Phys. 65, 700(1976).Author Institution: Department of Physics, Texas Tech UniversityThe theory of vibration-large amplitude internal motion interaction in is used to calculate these contributions to the effective Eamiltonian for internal rotation when the internal rotor has a three fold axis of symmetry. Calculations are made for four isotopic species of methyl alcohol, two isotopic species of acetaldehyde and trifluoroacetaldehyde, and perfluoroacetyl fluoride. The dynamic contribution to the potential energy coefficient ranges from -3 to . The potential energy coefficient shows a dependence of a few tens of upon the state of the perpendicular vibrations. A cos6 dependence of the reduced torsional coefficient is of the order of 0.05% of . The mixing of internal rotation with other vibrations cannot account for the decrease in barrier for methyl alcohol with deuterium substitution. Actually the calculation gives an increase in barrier of comparable magnitude to the decrease observed for compared to
THE MICROWAVE SPECTRUM OF BENZALDEHYDE
No full textAuthor Institution: Department of Physics, University of Wyoming; Department of Physics, Texas Technological CollegeThe ground state rotational absorption spectra of and have been investigated in the 26.5 to 40 GHz region and have been correlated with the assignments of previous work. Preliminary values for the rotational constants for are and for are and . Study of the torsional vibrational states is in progress and results of this study will be presented. An estimate of the height of the barrier to internal rotation based on accurate relative intensity measurements will also be presented. This work has been supported in part by the National Aeronautics and Space Administration. T. Kojima, C.R. Quade and C.C. Lin, Bull. Am. Phys. Soc. 7, 44 (1962)
Paleo-Reconstruction of the Coban Formation at Los Chorros, Central Guatemala
No full textThis item is available only to currently enrolled UTSA students, faculty or staff. To download, navigate to Log In in the top right-hand corner of this screen, then select Log in with my UTSA ID.The Cretaceous Period (66-145 Ma) is recognized by episodes of extreme climates, associated with global greenhouse conditions that favored widespread production of shallow marine carbonate platforms. Despite their sensitivity to the quality and chemistry of seawater as well as oceanographic conditions, carbonate platforms can thrive for extended periods of time, making them a valuable record of paleoceanographic and paleoclimatic changes.
The Cobàn Formation is a thick, shallow-marine succession deposited from the Aptian to Santonian over Guatemala. In outcrop, it is divided into the lower dolomitic and upper limestone units. Three platform drownings punctuate the development of this platform from the Aptian to Cenomanian, and are represented by more basinal, anoxic deposits attributed to a relative sea level rise. Because of the lack of a robust biostratigraphic framework, the dating of its sediments and subordinated drowning facies is not well constrained.
This study focuses on a 100 m section belonging to the upper limestone unit of the Cobàn Formation. Exposure is due to a major landslide that occurred on 4 January, 2009, detaching more than 5 million cubic meters of Cretaceous limestone. The aim of this study is to constrain the age of the section through biostratigraphy evolution and chemostratigraphy.
Based on the occurrence of the miliolid Nummoloculina hemi, the section is constrained to Albian-Cenomanian. Additionally, chemostratigraphic correlation further constrained the age to middle Albian-lower Cenomanian. Petrographic analysis suggests that sediments at the measured section were deposited in a restricted platform environment with an early flooding event witnessed by an organic mudstone facies at the base of the section. Bulk rock geochemical data suggest that this mudstone facies was deposited during times of bottom water dysoxia during the early stages of a sea level rise.Geoscience
Transportation investments in the Philadelphia metropolitan area: who benefits? Who pays? And what are the consequences?
No full textIn this paper, the author examines the geographic distribution of transportation investments as well as the question of who pays for the investments in the Philadelphia metropolitan area, focusing on differences between the city and its surrounding Pennsylvania suburban counties. The author presents estimates of total, per capita, and per user benefits of highway investments, as well as fees generated by highway users at the county level. The author also examines the combined highway and transit investments in the suburbs as a whole and in the city. ; There are three central findings in this analysis: (1) Highway capital expenditures in the Greater Philadelphia region are significantly higher on a per capita basis in the Pennsylvania suburbs than in the city of Philadelphia. Over the 10 years from 1986-1995, expenditures benefiting suburban residents are estimated to be 424 per capita. (2) Total highway user fees generated differ significantly across communities because of different auto ownership rates. Users fees do not, however, have differential effects on the attractiveness of communities because the user fees that individual drivers pay are the same across communities. (3) The per user differences between Philadelphia and its suburbs are smaller than per capita differences. Per user differences affect the degree to which car travel is favored in the city versus the suburbs, but it does not capture the location effects of investment in transportation infrastructure. ; The difference in per capita expenditures is likely to have a significant effect on the competitive position of the city of Philadelphia relative to its suburbs. Highway investments have provided an economically significant, although not overwhelming, incentive for suburban rather than city locations for people and firms. The author estimates that the highway investment differential reduces employment in the city by about 40,000 jobs.Local transit ; Philadelphia (Pa.)
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K-AR Geochronology of Authigenic Clays to Date Paleoweathering
No full textAncient soils, or paleosols, form at the intersection of the atmosphere, lithosphere, hydrosphere, and biosphere, and contain valuable information about their formation environments. Paleosols are used to study Earth’s past climate and are one of few continental paleoclimate proxies widely available in the rock record. Before making interpretations about Earth’s past using paleosols, we must know when the original soil formed. Although there are a few existing geochronometers that have been used to date paleosols, including U-Pb geochronology of soil carbonates and 40Ar/39Ar dating of supergene oxides, they are not suitable for most paleosols. In this study, we use K-Ar geochronology and illite age analysis (IAA) to date illite formed during low degrees of weathering of granitic parent material in soils and paleosols.IAA is used to date shallow, brittle faulting and diagenesis of sedimentary rocks. Two polytypes of illite are found in these environments, low-temperature (< 200 °C) 1Md illite and the high-temperature 2M1 illite. Because of the small crystal size of clays, it is impossible to separate pure fractions of these polytypes from each other. This means that bulk clay mixtures often include illite that formed in different environments at different times. In IAA studies, clay samples are separated into multiple size fractions. The proportion of inherited 2M1 illite in each size fraction is quantified by X-ray diffraction (XRD), and each size fraction is dated using K-Ar. As the proportion of 2M1 illite decreases, the age of the size fractions will approach the age of 1Md illite formation. The proportion of 2M1 illite in each size fraction is then plotted against its age, and a linear regression is used to determine the age of pure 1Md illite formation. To test the use of IAA on paleosols, I dated samples from both a modern, active soil, and from weathered granite beneath the late Proterozoic Great Unconformity. I measured a 1Md illite age of -2.52 ± 11.3 Ma on an active, semi-arid soil capping the Granite Wash Member of the St. David Formation near Benson, Arizona. This age is effectively 0 Ma, showing that 1Md illite is actively forming in the soil through pedogenesis. The measured 2M1 illite age is 396 ± 68.6 Ma, much older than the expected age (54.6 ± 0.2 Ma) of the parent Texas Canyon Quartz Monzonite. Using bulk elemental and 87Sr/86Sr measurements of a profile through the soil, I show that dust is present in the A horizon and is vertically mixed throughout the soil. This aeolian input is likely the source of this older 2M1 illite. I analyzed two samples of weathered Pikes Peak Granite beneath the Great Unconformity in Manitou Springs, Colorado to show the potential power of using IAA to date pedogenic illite. I determined that the Pikes Peak Granite was in the near-surface environment and weathered at 867 ± 9.6 Ma. This age comes from a clay sample with no 2M1 illite, but orthoclase from the Pikes Peak Granite was another inherited K-bearing mineral present in the clay size fractions. Diffusion modelling of 40Ar in illite shows that the age of this sample would not have been affected by thermally activated diffusion of 40Ar due to regional burial reheating. This age supports the hypothesis that the cause of exhumation and formation of the Great Unconformity in this location was the late stages of the assembly of Rodinia prior to 850 Ma leading to long term basement erosion. Finally, to better understand the limitations of IAA studies, I explored two statistical methods for calculating IAA ages. The first uses theoretical error propagation to combine average K, 40Ar*, 1Md illite, and 2M1 illite concentrations into K-Ar ages and proportions of 2M1 illite for each clay size fraction. The second uses a bootstrap resampling routine and Monte Carlo simulations to calculate these values. I then tested how varying several parameters in IAA data affects the uncertainty on the pure 1Md illite age calculated using a York-style weighted linear regression. I found that the most important parameters are the age uncertainty of each size fraction and the range of proportions of 2M1 illite between the size fractions. The most important size fraction is the one with the lowest proportion of 2M1 illite. These analyses can be used as a road map to improve the methodology in IAA, especially when working with samples that require higher age precision.Release after 01/21/202
The Impact of Education on a Mental Health Provider’s Willingness to Adopt Innovation in the Diagnostic Process
No full textabstract: In today’s healthcare environment, there is ample evidence to support early identification of disease and implementation of effective treatment to improve patient outcomes. The objectives of this clinical intervention were twofold; the implementation of an innovative change within an organization, allowing for systematic screening through incorporation of the Mood Disorder Questionnaire (MDQ), and evaluation of mental health provider’s willingness to incorporate practice change. A pre and post quasi-experimental design evaluated the attitude of providers regarding practice change using the Evidence-Based Practice Attitude Scale and the utilization of the MDQ following educational intervention. Parametric testing was used to explore the relationship between education specific to practice change and the provider's attitude through the use of the paired t test. The Chi-square test evaluated the use of the MDQ by clinic healthcare providers in relation to an innovative practice change. Results of this study illustrate enhanced provider willingness to adopt innovation and increased MDQ use following the intervention. Ensuring provider access to screening tools and education during the process of practice change provides a strategy for early intervention enhanced willingness to support practice evolution
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