RDS-21 Face-Gear Surface Durability Tests

Experimental fatigue tests were performed to determine the surface durability life of a face gear in mesh with a tapered spur involute pinion. Twenty-four sets of gears were tested at three load levels: 7200, 8185, and 9075 lb-in face gear torque, and 2190 to 3280 rpm face gear speed. The gears were carburized and ground, shot-peened and vibro-honed, and made from VIM-VAR Pyrowear 53 steel per AMS 6308. The tests produced 17 gear tooth spalling failures and 7 suspensions. For all the failed sets, spalling occurred on at least one tooth of all the pinions. In some cases, the spalling initiated a crack in the pinion teeth which progressed to tooth fracture. Also, spalling occurred on some face gear teeth. The AGMA endurance allowable stress for a tapered spur involute pinion in mesh with a face gear was determined to be 275 ksi for the material tested. For the application of a tapered spur involute pinion in mesh with a face gear, proper face gear shim controlled the desired gear tooth contact pattern while proper pinion shim was an effective way of adjusting backlash without severely affecting the contact pattern

Helical Face Gear Development Under the Enhanced Rotorcraft Drive System Program

U.S. Army goals for the Enhanced Rotorcraft Drive System Program are to achieve a 40 percent increase in horsepower to weight ratio, a 15 dB reduction in drive system generated noise, 30 percent reduction in drive system operating, support, and acquisition cost, and 75 percent automatic detection of critical mechanical component failures. Boeing s technology transition goals are that the operational endurance level of the helical face gearing and related split-torque designs be validated to a TRL 6, and that analytical and manufacturing tools be validated. Helical face gear technology is being developed in this project to augment, and transition into, a Boeing AH-64 Block III split-torque face gear main transmission stage, to yield increased power density and reduced noise. To date, helical face gear grinding development on Northstar s new face gear grinding machine and pattern-development tests at the NASA Glenn/U.S. Army Research Laboratory have been completed and are described

Total and positronium formation cross sections for positron scattering from H2O and HCOOH

Total and positronium formation cross sections have been measured for positron scattering from H2O and HCOOH using a positron beam with an energy resolution of 60 meV (full-width at half-maximum (FWHM)). The energy range covered is 0.5–60 eV, including an investigation of the behavior of the onset of the positronium formation channel using measurements with a 50 meV energy step, the result of which shows no evidence of any channel coupling effects or scattering resonances for either molecule

Making the Most of Mealtimes (M3): protocol of a multi-centre cross-sectional study of food intake and its determinants in older adults living in long term care homes

Background: Older adults living in long term care (LTC) homes are nutritionally vulnerable, often consuming insufficient energy, macro-and micronutrients to sustain their health and function. Multiple factors are proposed to influence food intake, yet our understanding of these diverse factors and their interactions are limited. The purpose of this paper is to fully describe the protocol used to examine determinants of food and fluid intake among older adults participating in the Making the Most of Mealtimes (M3) study. Methods: A conceptual framework that considers multi-level influences on mealtime experience, meal quality and meal access was used to design this multi-site cross-sectional study. Data were collected from 639 participants residing in 32 LTC homes in four Canadian provinces by trained researchers. Food intake was assessed with three-days of weighed food intake (main plate items), as well as estimations of side dishes, beverages and snacks and compared to the Dietary Reference Intake. Resident-level measures included: nutritional status, nutritional risk; disease conditions, medication, and diet prescriptions; oral health exam, signs of swallowing difficulty and olfactory ability; observed eating behaviours, type and number of staff assisting with eating; and food and foodservice satisfaction. Function, cognition, depression and pain were assessed using interRAI LTCF with selected items completed by researchers with care staff. Care staff completed a standardized person-directed care questionnaire. Researchers assessed dining rooms for physical and psychosocial aspects that could influence food intake. Management from each site completed a questionnaire that described the home, menu development, food production, out-sourcing of food, staffing levels, and staff training. Hierarchical regression models, accounting for clustering within province, home and dining room will be used to determine factors independently associated with energy and protein intake, as proxies for intake. Proportions of residents at risk of inadequate diets will also be determined. Discussion: This rigorous and comprehensive data collection in a large and diverse sample will provide, for the first time, the opportunity to consider important modifiable factors associated with poor food intake of residents in LTC. Identification of factors that are independently associated with food intake will help to develop effective interventions that support food intake.Canadian Institutes of Health Research (CIHR) , The PI is an endowed research chair with the Schlegel-University of Waterloo Research Institute for Aging; half of her salary is provided by this non-profit organizatio

Low-energy positron interactions with xenon

Low-energy interactions of positrons with xenon have been studied both experimentally and theoretically. The experimental measurements were carried out using a trap-based positron beam with an energy resolution of ̃80 meV, while the theoretical calculat

Concert recording 2018-02-09

[Track 1]. Marche á huit instrumens á vent / Nannette Streicher -- [Track 2]. Dixtuor pour instruments á vent. I. Allegro moderato II. Moderato [Track 3]. III. Andante - Allegro scherzando [Track 4]. IV. Cantabile [Track 5]. V. Allegro risoluto / Claude Arrieu, née Louise Marie Simon -- [Track 6]. Octet for windinstruments / Tera de Marez Oyens -- [Track 7]. The unfortunate traveller, suite for brass band. I. Introduction II. Scherzo [Track 8]. III. Interlude [Track 9]. IV. March / Imogen Holst

Tuneable drug-loading capability of chitosan hydrogels with varied network architectures

Advanced bioactive systems with defined macroscopic properties and spatio-temporal sequestration of extracellular biomacromolecules are highly desirable for next generation therapeutics. Here, chitosan (CT) hydrogels were prepared with neutral or negatively charged cross-linkers in order to promote selective electrostatic complexation with charged drugs. CT was functionalized with varied dicarboxylic acids, such as tartaric acid, poly(ethylene glycol) bis(carboxymethyl) ether, 1,4-phenylenediacetic acid and 5-sulfoisophthalic acid monosodium salt (PhS), whereby PhS was hypothesized to act as a simple mimetic of heparin. Attenuated total reflectance Fourier transform infrared spectroscopy showed the presence of Cdouble bond; length as m-dashO amide I, N–H amide II and Cdouble bond; length as m-dashO ester bands, providing evidence of covalent network formation. The cross-linker content was reversely quantified by proton nuclear magnetic resonance on partially degraded network oligomers, so that 18 mol.% PhS was exemplarily determined. Swellability (SR: 299 ± 65–1054 ± 121 wt.%), compressibility (E: 2.1 ± 0.9–9.2 ± 2.3 kPa), material morphology and drug-loading capability were successfully adjusted based on the selected network architecture. Here, hydrogel incubation with model drugs of varied electrostatic charge, i.e. allura red (AR, doubly negatively charged), methyl orange (MO, negatively charged) or methylene blue (MB, positively charged), resulted in direct hydrogel–dye electrostatic complexation. Importantly, the cationic compound, MB, showed different incorporation behaviours, depending on the electrostatic character of the selected cross-linker. In light of this tunable drug-loading capability, these CT hydrogels would be highly attractive as drug reservoirs towards e.g. the fabrication of tissue models in vitro