Improved oil-off survivability of tapered roller bearings

The aim of this program is to improve the oil-off survivability of a tapered roller bearing when applied to a helicopter transmission, since the tapered bearing has shown a performance advantage in this application. However, the critical roller end-rib conjunction is vulnerable to damage in an oil-off condition. Three powdered metal materials were selected to use as the rib material for oil-off evaluation. These were: M2 steel to a 65% density, CBS 1000M 65% density, and CBS 1000M 75% density. The bearing styles tested were ribbed cone (inner race) and ribbed cup (outer race). Carburized solid CBS 600 was also used as a ribbed material for comparison of oil-off results. The tests were conducted at six speeds from 4000 rpm (0.26 million DN) through 37000 rpm (2.4 million DN).The ribbed cup style bearing achieved longer lives than the ribbed cone style. A standard bearing lasted only 10 minutes at 4000 rpm; however, the 30-min oil-off goal was achieved through 11000 rpm using the survivable ribbed cup bearing. The oil-off lives at 37000 rpm were less than 10 seconds. The grinding of the powder metal materials and surface preparation to achieve an open porosity is extremely critical to the oil-off performance of the powder metal component

Systemic Uncertainty: An Examination of Its Causes and Repercussions

This paper examines the nature of systemic uncertainty and the character of public policy which causes it by analyzing two time periods as case studies of how systemic uncertainty is generated by public policy choices. I analyze financial data and polling data for evidence of systemic uncertainty to identify the form of public policy and political leadership which results in the occurrence of uncertainty. My findings suggest that systemic uncertainty is generated by a lack of commitment to the protection of private property and/or a willingness to arbitrarily implement changes to the tax and regulatory structure in the future

Prolonged Survival of Human Skin Xenografts on Antithymocyte Serum-Treated Mice: Failure to Produce Verrucae by Inoculation with Extracts of Human Warts

This report describes an experimental system whereby human skin was grafted to immunosuppressed mice, thus avoiding the restrictions imposed by the use of human subjects or tissue cultures. Grafts remained in good condition for the subsequent life of the animal, as long as eight months. The human skin xenografts were inoculated with an extract of verrucae vulgaris, but no warts developed during the period of observation

Replication of Molluscum Contagiosum Virus

AbstractMolluscum contagiosum virus (MCV) infects preadolescent children and sexually active adults, frequently causing a disfiguring cutaneous disease in immunosuppressed HIV-infected individuals. The development of an efficacious treatment regime has been hampered by the failure to replicate the virus in the laboratory. Here we report the first demonstration of MCV replication in an experimental system. In human foreskin grafts to athymic mice, MCV induced morphological changes which were indistinguishable from patient biopsies and included the development and migration of molluscum bodies containing mature virions to the epidermal surface

Podofilox-Induced Regression of Shope Papillomas May Be Independent of Host Immunity

We tested the hypothesis that infiltrating leukocytes might contribute to papilloma destruction following podofilox treatment. New Zealand White (NZW) rabbits were inoculated with cottontail rabbit papillomavirus (CRPV) onto abraded areas of the dorsal skin. At 21 d after viral inoculation, 5.0% podofilox solution was applied to some papillomas, whereas others were used as controls. Three rabbits were sacrificed at each of three different periods after treatment initiation (1, 4, and 7 d). Four monoclonal antibodies (MoAbs), RG-16 (for B cells), L11/135 (specific for T cells), 2C4 (specific for class II antigen), and Ki67 (specific for proliferating cells), were used in an immunohistochemical study. All positive cells and total cells in the field were counted with an ocular grid. After 1 d of treatment, proliferation of papilloma cells was strongly suppressed in treated papillomas, but leukocytic infiltration was not altered. At 4 d and 7 d of treatment, there were substantial increases (about two to three times) in the numbers of B and T cells and class II – expressing leukocytes. The upper layers of the papillomas were highly necrotic and cell proliferation was absent in an layers. These data support the view that podofilox has a direct toxic effect on papilloma tissue. Leukocyte infiltration is not strongly associated with papilloma tissue and may not contribute to papilloma destruction

Image-Guided Raman Spectroscopic Recovery of Canine Cortical Bone Contrast in Situ

Raman scattering provides valuable biochemical and molecular markers for studying bone tissue composition with use in predicting fracture risk in osteoporosis. Raman tomography can image through a few centimeters of tissue but is limited by low spatial resolution. X-ray computed tomography (CT) imaging can provide high-resolution image-guidance of the Raman spectroscopic characterization, which enhances the quantitative recovery of the Raman signals, and this technique provides additional information to standard imaging methods. This hypothesis was tested in data measured from Teflon tissue phantoms and from a canine limb. Image-guided Raman spectroscopy (IG-RS) of the canine limb using CT images of the tissue to guide the recovery recovered a contrast of 145:1 between the cortical bone and background. Considerably less contrast was found without the CT image to guide recovery. This study presents the first known IG-RS results from tissue and indicates that intrinsically high contrasts (on the order of a hundred fold) are available

Modeling and Simulation of Coating Growth on Nanofibers

This work presents modeling and simulation results of a procedure to coat nanofibers and core-clad nanostructures with thin film materials using plasma enhanced physical vapor deposition. In the experimental effort that motivates the modeling, electrospun polymer nanofibers are coated with metallic materials under different operating conditions to observe changes in the coating morphology. The modeling effort focuses on linking simple models at the reactor, nanofiber, and atomic levels to form a comprehensive model. Numerical simulations that link the concentration field with the evolution of the coating free surface predict that as the Damkohler number is increased the coating morphology changes from a wavy to a nodular to a dendritic needle-type form as observed experimentally

Effects of ingesting JavaFit Energy Extreme functional coffee on aerobic and anaerobic fitness markers in recreationally-active coffee consumers

The purpose of this study was to examine the effects of ingesting JavaFit™ Energy Extreme (JEE) on aerobic and anaerobic performance measures in recreationally-active male and female coffee drinkers. Five male (27.6 ± 4.2 yrs, 93.2 ± 11.7 kg, 181.6 ± 6.9 cm) and five female (29 ± 4.6 yrs, 61.5 ± 9.2 kg, 167.6 ± 6.9 cm) regular coffee drinkers (i.e., 223.9 ± 62.7 mg·d(-1 )of caffeine) participated in this study. In a cross-over, randomized design, participants performed a baseline (BASELINE) graded treadmill test (GXT) for peak VO(2 )assessment and a Wingate test for peak power. Approximately 3–4 d following BASELINE testing, participants returned to the lab for the first trial and ingested 354 ml of either JEE or decaffeinated coffee (DECAF), after which they performed a GXT and Wingate test. Criterion measures during the GXT included an assessment of peakVO(2 )at maximal exercise, as well as VO(2 )at 3 minutes and 10 minutes post-exercise. Additionally, time-to-exhaustion (TTE), maximal RPE, mean heart rate (HR), mean systolic pressure (SBP), and mean diastolic blood pressure (DBP) were measured during each condition. Criterion measures for the Wingate included mean HR, SBP, DBP, peak power, and time to peak power (TTP). Participants then returned to the lab approximately one week later to perform the second trial under the same conditions as the first, except consuming the remaining coffee. Data were analyzed using a one way ANOVA (p < 0.05). Our results indicate that JEE significantly increased VO(2 )at 3 minutes post-exercise when compared to BASELINE (p = 0.04) and DECAF (p = 0.02) values, which may be beneficial in enhancing post-exercise fat metabolism

Muscle fiber and performance adaptations to resistance exercise with MyoVive, colostrum or casein and whey supplementationa

This is the publisher's version, also found at http://ehis.ebscohost.com/ehost/detail?sid=ba69ee0d-97cf-4a2c-a1a2-2c26fb60d65c%40sessionmgr13&vid=1&hid=2&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=s3h&AN=10725638To determine the effects of 12 weeks of resistance exercise with MyoVive and/or colostrum supplementation, 19 male and female recreationally weighttrained subjects (X ± SE; age = 28.3 ± 6.9 yrs; hgt = 68.2 ± 3.8 cm) were divided into MyoVive + colostrum (n = 4), MyoVive + casein & whey (n = 4), colostrum + casein & whey (n = 6), and casein & whey (n = 5) groups. All groups similarly increased (p < .05) 1 repetition maximum (RM) leg press (kg; pre = 158.6 ± 12.8, post = 189.3 ± 11.3), body mass (kg; pre = 79.0 ± 3.2, post = 80.7 ± 3.8), and lean body mass (kg; pre = 60.1 ± 3.1, post = 62.2 ± 2.8). Increases were observed for peak force (N; all loads), peak velocity (m.s-1; 70% & 40% 1 RM), and peak power (W; 70% & 40% 1 RM) for all groups for the leg press exercise, with no differences between groups. When performance data were adjusted for body mass, lean body mass, lower body lean mass as determined by DEXA, or % change, no group differences were observed. Relative (%) fiber type content, cross-sectional areas (mm2), % fiber type areas, or % myosin heavy chain expression did not change for any group. These data suggest that MyoVive and colostrum supplementation have no greater effect on cellular and performance adaptations when compared to casein and whey protein

Modeling, Simulation, and Experiments of Coating Growth on Nanofibers

This work is a comparison of modeling and simulation results with experiments for an integrated experimental/modeling investigation of a procedure to coat nanofibers and core-clad nanostructures with thin film materials using plasma enhanced physical vapor deposition. In the experimental effort, electrospun polymer nanofibers are coated with metallic materials under different operating conditions to observe changes in the coating morphology. The modeling effort focuses on linking simple models at the reactor level, nanofiber level and atomic level to form a comprehensive model. The comprehensive model leads to the definition of an evolution equation for the coating free surface around an isolated nanofiber. This evolution equation was previously derived and solved under conditions of a nearly circular coating, with a concentration field that was only radially dependent and that was independent of the location of the coating free surface. These assumptions permitted the development of analytical expressions for the concentration field. The present work does not impose the above-mentioned conditions and considers numerical simulations of the concentration field that couple with level set simulations of the evolution equation for the coating free surface. Further, the cases of coating an isolated fiber as well as a multiple fiber mat are considered. Simulation results are compared with experimental results as the reactor pressure and power, as well as the nanofiber mat porosity, are varied. (C) 2008 American Institute of Physics