6 research outputs found
Evaluation of the Spherical Flange Concept for a Rocket Engine
Due to the inherent tolerance variability of hardware, flange misalignments occur during installation of mating components for a liquid propellant rocket engine. Flange misalignments include axial, lateral, and angular offsets. If these misalignments are high, they can impart significant loads into the two mating components. These significant loads can then be a driver in the design of the propellant ducts. Such was the case for the Rocketdyne RS-83 engine design for the Space Launch Initiative Program. To address this flange misalignment issue, Marshall Space Flight Center joined with Rocketdyne to develop and test a spherical flange system that allows for misalignment, yet reduces loads imparted, and at the same time provides sufficient sealing against leakage. The flange design was tested to evaluate and compare performance parameters such as misalignment and leakage. The environmental conditions ranged from -100 to 400 degrees Fahrenheit (F) with 1000 to 4000 pounds per square inch gage (psig) pressure. The desirable design features will be extracted and synthesized into a new flange design concept. This paper will address the spherical flange design and the test results
Prevalence of components of the metabolic syndrome according to birthweight among overweight and obese children and adolescents
Background/objectives: Extremes of birthweight (BW) have been associated with increased rates of metabolic risks. The objective was to study the prevalence of metabolic risks markers among obese and overweight (OW) subjects according to BW. Subjects/methods: A cross-sectional study was performed in a cohort of 1002 patients (2 - 18 years, 40.6 % male) evaluated for OW or obese subjects in two private clinics. Anthropometrics, fasting lipids, glycemia, and insulin were obtained. Results: Of the subjects, 76.1 % were born appropriate for gestational age (AGA), 10.9 % small for gestational age (SGA), and 13 % large for gestational age (LGA). Children born LGA presented a more severe degree of obesity compared with those born AGA and SGA (p < 0.0001). No differences in glycemia, insulin, and lipid levels were detected among the groups. Abnormal glucose was found in 37 subjects: one with type 2 diabetes mellitus (from the previously glucoseintolerant subjects), 10 with glucose intolerance