Component specific modeling

The objective was to develop and verify a series of interdisciplinary modeling and analysis techniques specialized to address hot section components. These techniques incorporate data as well as theoretical methods from many diverse areas, including cycle and performance analysis, heat transfer analysis, linear and nonlinear stress analysis, and mission analysis

Component specific modeling

The objective is to develop and verify a series of interdisciplinary modeling and analysis techniques that have been specialized to address three specific hot section components. These techniques will incorporate data as well as theoretical methods from many diverse areas including cycle and performance analysis, heat transfer analysis, linear and nonlinear stress analysis, and mission analysis. The new methods developed will be integrated to provide an accurate, efficient, and unified approach to analyzing combustor burner liners, hollow air-cooled turbine blades, and air-colled turbine vanes. For these components, the methods developed will predict temperature, deformation, stress, and strain histories throughout a complete flight mission

Component-specific modeling

Accomplishments are described for a 3 year program to develop methodology for component-specific modeling of aircraft hot section components (turbine blades, turbine vanes, and burner liners). These accomplishments include: (1) engine thermodynamic and mission models, (2) geometry model generators, (3) remeshing, (4) specialty three-dimensional inelastic structural analysis, (5) computationally efficient solvers, (6) adaptive solution strategies, (7) engine performance parameters/component response variables decomposition and synthesis, (8) integrated software architecture and development, and (9) validation cases for software developed

Structural analysis demonstration of constitutive and life models

The overall objective of this program is to demonstrate the applicability of NASA-developed advanced constitutive and life damage models for calculating cyclic structural response and crack initiation in selected components of reusable space propulsion systems. The computer model resulting from this program will enable the user to produce an accurate life prediction of hot gas path, life limiting components of propulsion systems such as the space shuttle main engine (SSME). Previously developed computer models addressing constitutive modeling and life damage will be combined in an advanced finite element analysis to generate a sophisticated baseline life prediction program. A material data base will be established for the constitutive and life models parametrically involving temperature, strain range, strain rate, mean strain/stress, and dwell time. The verified computer program will be used to accomplish the life predictions of three SSME critical components as evidence of the model functionality

The Relation of Stress and Depression to Interdialytic Weight Gain in Hemodialysis Patients

Nonadherence to fluid restrictions is a common problem with serious health consequences for patients with end-stage renal disease (ESRD). For the present study, the authors evaluated psychological variables of stress, as measured by major and minor life events, and depression. They sought to determine the role of these events in patients’failure to adhere to fluid restrictions as measured by increased interdialytic weight gain. Forty-two hemodialysis patients completed inventories assessing major life events, daily stressful events, and depression on three consecutive dialysis sessions. Fluid adherence was measured by interdialytic weight gain. A path analysis model found daily minor stress to have a direct effect on nonadherence, whereas there was a direct inverse effect of depression on nonadherence. Possible mechanisms and implications for future studies arediscussed

Why patients seek bariatric surgery: does insurance coverage matter?

Despite increasing prevalence of bariatric surgery, little is known about why patients seek out this treatment option. Heads Up is an observational study sponsored by a large benefits management group that examines surgical and nonsurgical approaches to weight management in obese adults. This study examined patients\u27 reasons for choosing surgery. The sample included 360 adult obese patients seeking bariatric surgery who were invited to volunteer for a surgical or a medical weight loss program by their insurer. Participants rank ordered their top three reasons as a deciding factor for choosing to consider surgery. The top three reasons were concerns regarding health (52%), current obesity-related medical conditions (28%), and improved physical fitness (5%). Overall, 13% endorsed insurance coverage as one of their top three choices. When insurance coverage is assured, health and functionality issues were the major reasons reported for obese adults choosing to undergo bariatric surgery