A constitutive model with damage for high temperature superalloys

A unified constitutive model is searched for that is applicable for high temperature superalloys used in modern gas turbines. Two unified inelastic state variable constitutive models were evaluated for use with the damage parameter proposed by Kachanov. The first is a model (Bodner, Partom) in which hardening is modeled through the use of a single state variable that is similar to drag stress. The other (Ramaswamy) employs both a drag stress and back stress. The extension was successful for predicting the tensile, creep, fatigue, torsional and nonproportional response of Rene' 80 at several temperatures. In both formulations, a cumulative damage parameter is introduced to model the changes in material properties due to the formation of microcracks and microvoids that ultimately produce a macroscopic crack. A back stress/drag stress/damage model was evaluated for Rene' 95 at 1200 F and is shown to predict the tensile, creep, and cyclic loading responses reasonably well

Nonadditivity of intermolecular forces - Effects on the third virial coefficient

Effects of nonadditive three body forces on third virial coefficien

Acceptance Versus Distraction for Unwanted Sexual Thoughts

This on-line study examined 67 participants who rated their sexual thought distress level as moderately distressing or greater, on the successfulness of an acceptance-based strategy and a distraction-based strategy for dealing with unwanted sexual thoughts. The study began with the completion of an assessment battery, which measured attitudes about sexual thoughts. During a pre-intervention three minute time period, participants were asked to record/report occurrences a previously identified unwanted sexual thought, if or when, it occurred. They were then randomly placed into one of three experimental conditions (e.g., acceptance-based, distraction-based, and a control group) in which they viewed a video presentation that taught strategies for dealing with unwanted sexual thoughts. After watching the presentation, participants again recorded occurrences of sexual thoughts during a three minute period. Participants also completed the questions again to assess attitudes about sexual thoughts post intervention. Thought frequencies decreased for all groups post intervention, while levels of acceptance increased for the acceptance-based group, and decreased for the control-based group. Participants in the distraction based group also rated their sexual thoughts as being more similar to acting on the thought post intervention

Parcel model simulations of aerosol ? warm phase cloud microphysics interactions over the Amazon

International audienceRecent observational studies have shown that biomass burning aerosol can modify the microstructure of convective clouds in tropical regions such as Indonesia and the Amazon. In such regions warm rain development is evidently suppressed during the burning season 5 relative to the wet season, as numerous condensation nuclei produce more numerous but smaller cloud droplets. It is not clear, however, whether rain formation is affected only by CCN or whether other factors such as giant CCN, updraft speeds, and atmospheric moisture also play important roles in the observed differences. These issues are addressed here using a simple parcel model to explain data collected during 10 the LBA-SMOCC-EMfiN! field campaign. The results suggest that polluted clouds in particular tend to be sensitive to each of these factors. When droplet concentrations exceed 500?1000 per cc, giant CCN (GCCN) become important by generating droplets that may eventually grow to precipitation size, though in cleaner environments warm rain occurs readily regardless of GCCN. Variations in the vertical velocity and in the 15 low-level moisture are also shown to affect polluted clouds, and should be taken into account in interpreting microphysical differences observed among continental clouds

Poisoned Bait as a Control for Grasshoppers

Grasshoppers have done considerable damage to South Dakota field crops the past few years. Last year reports from various parts of the state show severe injury to alfalfa, corn, small grains, gardens, and other crops. The injury usually centers around alfalfa fields but the grasshoppers attack and destroy almost any green crop available. It have been demonstrated in South Dakota that control measures can be adopted that will serve to keep these insects incheck. Natural factors are, of course, important in the control of any insect, and their many enemies greatly reduce the numbers of grasshoppers each year. However, our experience has proven that we cannot rely on these natural enemies to protect us from injury, it being necessary to add our own efforts to those of nature if we are to prevent loss

Inspections: Software development process for building defect free software applied in a small-scale software development environment

Inspections is a software management technique designed to produce higher quality software and improve programmer productivity. These improvements are achieved through rigorous examination of the products in each phase of the software development life-cycle. While the process has generally been applied to large-scale mainframe projects, this research demonstrates successful implementation of inspections in a small-scale, micro-processor based software development project

Monoaromatic compounds in ambient air of various cities: A focus on correlations between the xylenes and ethylbenzene

Speciation of o-xylene, m-xylene, p-xylene and ethylbenzene was performed by gas chromatography from ambient air and liquid fuel samples collected at various locations in 19 cities in Europe, Asia and South America. The xylene's mixing ratios were compared to each other from the various locations, which included urban air, traffic air and liquid fuel. For all samples, the xylenes exhibited robust correlations, and the slopes remained constant. The m-xylene/p-xylene ratio was found to be 2.33±0.30, and the m-xylene/o-xylene ratio was found to be 1.84±0.25. These ratios remain persistent even in biomass combustion experiments (in South America and South Africa). Comparing the xylenes to toluene and benzene indicate that combustion, but not fuel evaporation, is the major common source of the xylenes in areas dominated by automotive emissions. Although a wide range of combustion types and combustion efficiencies were encountered throughout all the locations investigated, xylenes and ethylbenzene ratios remained persistent. We discuss the implications of the constancies in the xylenes and ethylbenzene ratios on atmospheric chemistry