A Study of Large Droplet Ice Accretions in the NASA-Lewis IRT at Near-Freezing Conditions

This report documents the results of an experimental study on large droplet ice accretions which was conducted in the NASA-Lewis Icing Research Tunnel (IRT) with a full-scale 77.25 inch chord Twin-Otter wing section. This study was intended to: (1) document the existing capability of the IRT to produce a large droplet icing cloud, and (2) study the effect of various parameters on large droplet ice accretions. Results are presented from a study of the IRT's capability to produce large droplets with MVD of 99 and 160 microns. The effect of the initial water droplet temperature on the resultant ice accretion was studied for different initial spray bar air and water temperatures. The initial spray bar water temperature was found to have no discernible effect upon the large droplet ice accretions. Also, analytical and experimental results suggest that the water droplet temperature is very nearly the same as the tunnel ambient temperature, thus providing a realistic simulation of the large droplet natural icing condition. The effect of temperature, droplet size, airspeed, angle-of attack, flap setting and de-icer boot cycling time on ice accretion was studied, and will be discussed in this report. It was found that, in almost all of the cases studied, an ice ridge formed immediately aft of the active portion of the de-icer boot. This ridge was irregular in shape, varied in location, and was in some cases discontinuous due to aerodynamic shedding

A Study of Large Droplet Ice Accretion in the NASA Lewis IRT at Near-Freezing Conditions

Results of experiments designed to determine the effects of large droplet ice accretion on a NACA 23012 wing section are presented. Using primarily an icing condition with a median volumetric diameter droplet size of 160 micron and a liquid water content of 0.82 grams per cubic meter, the effects of various air temperatures, angles of attack, and de-icer boot cycle interval times on ice accretion were studied. Measurements of aerodynamic performance penalties due to the ice accretions were made. Results were also compared with similar tests conducted with a Twin Otter wing section in Part 1 of this study. The form of the ice from the large droplet cloud varied as a function of air total temperature; particularly at the near-freezing temperatures of 28 F to 34 F. Changing boot cycle interval time did not prevent formation of an ice ridge. The most detrimental aerodynamic effects occurred at an air total temperature of 28 F

A sustainable agriculture course delivered nationally via AG*SAT

A sustainable agriculture course was developed during 1990-1991 at Iowa State University to examine the development of modern agricultural practices and how they affect the social and ecological environment. According to the project investigators, the purpose of the course was to introduce students to the concept of systemic thinking and to humanist methods of inquiry. They also wished to help students recognize the limitations of scientific reductionism as an exclusive method of inquiry. Because of this general philosophical approach, they regarded this course as one that addressed contemporary agricultural issues rather than a course in agricultural scienceperse

Influence of Time of Application of Nitrogen Fertilizer on Corn Yields

Soil moisture conditions can have a large effect on crop responses to nitrogen fertilization. Kentucky\u27s usual climatic pattern of periods of heavy rainfall and relatively warm temperatures during the winter and spring seasons influences expected yield responses of corn to applied nitrogen. If nitrogen fertilizer is applied in late winter or early spring, some of it may be lost before the plants have made sufficient growth to take up appreciable quantities. The amount of loss that might be expected will be influenced by the amount of rainfall, temperature, amount of organic matter and drainage of the soil

Weak-Localization and Integrability in Ballistic Cavities

We demonstrate the existence of an interference contribution to the average magnetoconductance, G(B), of ballistic cavities and use it to test the semiclassical theory of quantum billiards. G(B) is qualitatively different for chaotic and regular cavities, an effect explained semiclassically by the differing classical distribution of areas. The magnitude of G(B) is poorly explained by the semiclassical theory of coherent backscattering (elastic enhancement factor)-- correlations beyond time-reversed pairs of trajectories must be included-- but is in agreement with random matrix theory.Comment: 12 pages + 3 figures, revtex, hub-92-w

Periodontal regeneration risk assessment in the treatment of intrabony defects.

BACKGROUND: Regenerative approaches performed in periodontics seems to be efficient in treating intrabony defects. There are, however, many factors that may affect the predictability of the regenerative procedures. The present article aimed to propose a new risk assessment tool for treating periodontal intrabony defects by regenerative therapy. METHODS: Different variables that could affect the success of a regenerative procedure were considered based on their impact on (i) the wound healing potential, promoting wound stability, cells, and angiogenesis, or (ii) the ability to clean the root surface and maintain an optimal plaque control or (iii) aesthetics (risk for gingival recession). RESULTS: The risk assessment variables were divided into a patient, tooth, defect, and operator level. Patient-related factors included medical conditions such as diabetes, smoking habit, plaque control, compliance with supportive care, and expectations. Tooth-related factors included prognosis, traumatic occlusal forces or mobility, endodontic status, root surface topography, soft tissue anatomy, and gingival phenotype. Defect-associated factors included local anatomy (number of residual bone walls, width, and depth), furcation involvement, cleansability, and number of sides of the root involved. Operator-related factors should not be neglected and included the clinician\u27s level of experience, the presence of environmental stress factors, and the use of checklists in the daily routine. CONCLUSIONS: Using a risk assessment comprised of patient-, tooth-, defect- and operator-level factors can aid the clinician in identifying challenging characteristics and in the treatment decision process

Portfolio Vol. VI N 1

Wyman, John. Mrs. Brannon\u27s Bathtub . Prose. 1. Holbrook, Harold R. Sonnet . Poem. 7. Hayne, Barbara. Prayer of A Youth . Poem. 7. Egger, Ellen. An Evening . Poem. 7. Cuninggim, Merrimon. Lambda Pi Beta Mu . Prose. 9. Willett, Thelma. White Rosebuds . Poem. 11. Willett, Thelma. Span of A Life in Mine . Poem. 11. Willett, Thelma. Seventeen . Poem. 11. Willett, Thelma. Ave Atque Vale . Poem. 11. Willett, Thelma. The Ashes of Letters . Poem. 11. Miller, Albert. ...To One I Have Known and Loved . Prose. 12. Wyman, John. Browning the Artist . Prose. 14. Brannon, Pat. Revolution . Poem. 18. Forsberg, Nancy. Unnamed. Poem. 18. Kearns, Carolyn. A Co-Ed\u27s Wish . Poem. 18. Goetz, Marilyn. Fate\u27s Fury . Prose. 19. Harvey, Richard. Man Who Ate the Cheesecake . Prose. 21. Spike, Robert. Mechanikos . Poem. 22. Stodghill, Patricia. Anodyne . Poem. 23. Ladd, Donald. Torch-Light . Poem. 23

Young adult outcomes associated with teen pregnancy among high-risk girls in a randomized controlled trial of Multidimensional Treatment Foster Care

Teen pregnancy is associated with a host of deleterious outcomes for girls, such as drug use and poor parenting. Thus, reducing teen pregnancy rates could improve long-term developmental outcomes for girls, including adjustment during young adulthood. Based on the positive effects of Multidimensional Treatment Foster Care (MTFC) relative to group care (GC) in a study of adolescent girls (significantly fewer pregnancies reported in the 2-year follow-up for MTFC girls), the present study followed this sample into young adulthood (approximately 7 years post-baseline) to examine the effects of adolescent pregnancy on young adult substance use and pregnancy-related outcomes. All participants were randomly assigned to MTFC (N = 81) or GC (N = 85) as adolescents as part of a randomized controlled trial (RCT). Results from logistic regression analyses indicated that becoming pregnant during the 2-year follow-up was significantly related to illicit drug use, miscarriage from a new pregnancy, and child welfare involvement 7 years post-baseline. In addition, baseline marijuana use predicted marijuana use at 7 years post-baseline. © 2013 Copyright Taylor and Francis Group, LLC

Portfolio Vol. VI N 2

Wyman, John. Mrs. Brannon\u27s Bathtub . Prose. 1. Holbrook, Harold R. Sonnet . Poem. 7. Hayne, Barbara. Prayer of A Youth . Poem. 7. Egger, Ellen. An Evening . Poem. 7. Cuninggim, Merrimon. Lambda Pi Beta Mu . Prose. 9. Willett, Thelma. White Rosebuds . Poem. 11. Willett, Thelma. Span of A Life in Mine . Poem. 11. Willett, Thelma. Seventeen . Poem. 11. Willett, Thelma. Ave Atque Vale . Poem. 11. Willett, Thelma. The Ashes of Letters . Poem. 11. Miller, Albert. ...To One I Have Known and Loved . Prose. 12. Wyman, John. Browning the Artist . Prose. 14. Brannon, Pat. Revolution . Poem. 18. Forsberg, Nancy. Unnamed. Poem. 18. Kearns, Carolyn. A Co-Ed\u27s Wish . Poem. 18. Goetz, Marilyn. Fate\u27s Fury . Prose. 19. Harvey, Richard. Man Who Ate the Cheesecake . Prose. 21. Spike, Robert. Mechanikos . Poem. 22. Stodghill, Patricia. Anodyne . Poem. 23. Ladd, Donald. Torch-Light . Poem. 23

Built-in and induced polarization across LaAlO3_3/SrTiO3_3 heterojunctions

Ionic crystals terminated at oppositely charged polar surfaces are inherently unstable and expected to undergo surface reconstructions to maintain electrostatic stability. Essentially, an electric field that arises between oppositely charged atomic planes gives rise to a built-in potential that diverges with thickness. In ultra thin film form however the polar crystals are expected to remain stable without necessitating surface reconstructions, yet the built-in potential has eluded observation. Here we present evidence of a built-in potential across polar \lao ~thin films grown on \sto ~substrates, a system well known for the electron gas that forms at the interface. By performing electron tunneling measurements between the electron gas and a metallic gate on \lao ~we measure a built-in electric field across \lao ~of 93 meV/\AA. Additionally, capacitance measurements reveal the presence of an induced dipole moment near the interface in \sto, illuminating a unique property of \sto ~substrates. We forsee use of the ionic built-in potential as an additional tuning parameter in both existing and novel device architectures, especially as atomic control of oxide interfaces gains widespread momentum.Comment: 6 pages, 4 figures. Submitted to Nature physics on May 1st, 201