Investigation of Stacking Fault and Antiphase Boundary Segregation in Ni-Based Superalloys Using Density Functional Theory

Ni-base superalloys have a long history of use in jet turbine engines, and efforts to improve their performance in that application are ongoing. It is known that the precipitation of the Ni3Al ' phase within the disordered FCC phase strengthens the overall material. However, in the high-temperature environment found inside a turbine engine during operation, creep can cause the ' phase to transform to different, weaker phases along stacking faults, leading to a deterioration of performance. In the ' phase one mode of creep deformation is the formation of stacking fault ribbons, which consist of intrinsic stacking faults further shearing into antiphase boundaries (APBs). It is also known that certain alloying additions exhibit segregation to stacking faults. If segregating elements could be identified which segregate to the intrinsic stacking fault, but not to the APB, the inclusion of such elements could lead to improved creep strength in these alloys. To investigate this possibility, a density functional investigation of the segregation of W, Mo and Cr to both a superlattice intrinsic stacking fault (SISF) and an APB was performed. It was found that W, Mo and Cr all exhibit segregation to the SISF. In contrast, for the APB, Cr was either energy-neutral, or segregates, depending on the presence of additional nearby Cr, or on the specific lattice site upon which it was placed, while Mo and W did not segregate. Because W and Mo segregate to the SISF but not to the APB, the inclusion of these elements could provide a degree of protection against creep-related deterioration

Meteorological satellite products support for project COHMEX

The first year effort focussed on real-time support and satellite data collection during the field phase of COHMEX. Work efforts following the field phase of COHMEX concentrated on post-processing of the real-time data sets, and generation of enhanced, research-quality satellite data sets for selected COHMEX core days. These satellite-derived data sets will augment the special COHMEX conventional data base with high horizontal and temporal resolution information. The data sets will be examined for their usefulness in delineating important elements in the meteorological environment leading to convective activity. In addition, a limited research effort was conducted using the Cooperative Institute for Meteorological Satellite Studies (CIMSS) 4-d data assimilation system in conjunction with evaluating VISSR Atmospheric Sounder (VAS) and His-resolution Interferometer Sounder (HIS) data. The need to address the characteristics of the data types, and the problems they introduce into 4-d assimilation procedures is evident. The HIS instrument was flown aboard an ER-2 aircraft on several occasions during COHMEX. One of the flights was chosen for further study. Processed VAS soundings and COHMEX radiosonde data were also collected for this day. The case study included an evaluation of the HIS and VAS data and an impact study of the data on the assimilation system analysis

Mongoose ASIC microcontroller programming guide

The 'Mongoose' ASIC microcontroller is a radiation-hard implementation of the R3000 microprocessor. This document describes the internals of the microcontroller in a level of detail necessary for someone implementing a software design

InP homojunction solar cell performance on the LIPS 3 flight experiment

Performance data for the NASA Lewis Research Center indium phosphide n+p homojunction solar cell module on the LIPS 3 Flight Experiment is presented. The objective of the experiment is to measure the performance of InP cells in the natural radiation environment of the 1100 km altitude, 60+ deg inclination orbit. Analysis of flight data indicates that the performance of the four cells throughout the first year is near expected values. No degradation in short-circuit current was seen, as was expected from radiation tolerance studies of similar cells. Details of the cell structure and flight module design are discussed. The results of the temperature dependency and radiation tolerance studies necessary for normalization and analysis of the data are included

Conservation status of New Zealand freshwater invertebrates, 2013

The conservation status of 644 freshwater invertebrate taxa, across five Phyla, 28 Orders and 75 Families, was assessed using the New Zealand Threat Classification System (NZTCS) criteria. Forty-six species were ranked Nationally Critical, 11 Nationally Endangered and 16 Nationally Vulnerable. One hundred and seventy-two taxa were listed as Data Deficient. A full list is presented, along with summaries and brief notes on the most important changes. This list replaces all previous NZTCS lists for freshwater invertebrates

Experimental test of contextuality in quantum and classical systems

Contextuality is considered as an intrinsic signature of non-classicality, and a crucial resource for achieving unique advantages of quantum information processing. However, recently there have been debates on whether classical fields may also demonstrate contextuality. Here we experimentally configure a contextuality test for optical fields, adopting various definitions of measurement events, and analyse how the definitions affect the emergence of non-classical correlations. The heralded single photon state, a typical non-classical light field, manifests contextuality in our setup, while contextuality for classical coherent fields strongly depends on the specific definition of measurement events which is equivalent to filtering the non-classical component of the input state. Our results highlight the importance of definition of measurement events to demonstrate contextuality, and link the contextual correlations to non-classicality defined by quasi-probabilities in phase space.Comment: 17 pages, 7 figure

What can we say about substance use? Dominant discourses and narratives emergent from Australian media

Discourses are conceptualised as context-specific frameworks that constrain what can be presented as rational when considering psychoactive substances. Given the implications of this for Australian policy debate and development, research and health promotion, an integrative analysis explored the nature of the dominant discourses as they pertain to substance use. Newspaper articles spanning a 12-month period (April 2005 2006) were analysed with the analysis triangulated with visual media and newspapers from 5-years prior. We conclude that within Australia, psychoactive substance use is framed within the dominant discourses of medicine, morality, law, economics, politics and popular culture. The linguistic landscape circumscribed by each discourse is described and the power dynamics underpinning the maintenance of the discourses considered, with each discursive framework shown to delineate unique subject positions that define the numerous individuals concerned with substance use issues (e.g. substance users, politicians, medical experts, etc.)

Service organisation for the secondary prevention of ischaemic heart disease in primary care.

BACKGROUND: Ischaemic heart disease (IHD) is a major cause of mortality and morbidity and its prevalence is set to increase. Secondary prevention aims to prevent subsequent acute events in people with established IHD. While the benefits of individual medical and lifestyle interventions is established, the effectiveness of interventions which seek to improve the way secondary preventive care is delivered in primary care or community settings is less so. OBJECTIVES: To assess the effectiveness of service organisation interventions, identifying which types and elements of service change are associated with most improvement in clinician and patient adherence to secondary prevention recommendations relating to risk factor levels and monitoring (blood pressure, cholesterol and lifestyle factors such as diet, exercise, smoking and obesity) and appropriate prophylactic medication. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2007, Issue 4), MEDLINE (1966 to Feb 2008), EMBASE (1980 to Feb 2008), and CINAHL (1981 to Feb 2008). Bibliographies were checked. No language restrictions were applied. SELECTION CRITERIA: Randomised or quasi-randomised controlled trials of service organisation interventions in primary care or community settings in populations with established IHD. DATA COLLECTION AND ANALYSIS: Analyses were conducted according to Cochrane recommendations and Odds Ratios (with 95% confidence intervals) reported for dichotomous outcomes, mean differences (with 95% CIs) for continuous outcomes. MAIN RESULTS: Eleven studies involving 12,074 people with IHD were included. Increased proportions of patients with total cholesterol levels within recommended levels at 12 months, OR 1.90 (1.04 to 3.48), were associated with interventions that included regular planned appointments, patient education and structured monitoring of medication and risk factors, but significant heterogeneity was apparent. Results relating to blood pressure within target levels bordered on statistical significance. There were no significant effects of interventions on mean blood pressure or cholesterol levels, prescribing, smoking status or body mass index. Few data were available on the effect on diet. There was some suggestion of a \u22ceiling effect\u22 whereby interventions have a diminishing beneficial effect once certain levels of risk factor management are reached. AUTHORS\u27 CONCLUSIONS: There is weak evidence that regular planned recall of patients for appointments, structured monitoring of risk factors and prescribing, and education for patients can be effective in increasing the proportions of patients within target levels for cholesterol control and blood pressure. Further research in this area would benefit from greater standardisation of the outcomes measured