MODELING OF THE INFLUENCE OF THERMIC TREATMENT UPON THE MECHANICAL PROPERTIES OF ALUMINUM-TIN ALLOYS

In order to master and improve the quality and properties of the final products, the major industrial challenge lies in the possibility of controlling the morphology, size of microstructures that reside within the molded pieces, as well as their defects; this is the fundamental reason according to which we are more and more interested in mastering the growth and germination of such alloys, as well as the developing structures, at the time of solidification process. The modeling reveals as a valuable aid in the mastery of the formation of such heterogeneousness: segregation cells that are incompatible with industrial requirements. The whole work focuses upon the modeling of the segregation phenomenon of the four hypoeutectic alloys, Al1%Sn, Al2%Sn, Al3%Sn and Al4%Sn, as well as the tin effect upon certain mechanical properties of aluminum. Usually, the microstructure and mechanical behavior of such alloys as Al-Sn are directly influenced by some parameters such as composition, cooling velocity and homogenization process

MODELISATION DE L'INFLUENCE DU TRAITEMENT THERMIQUE SUR LES PROPRIETES MECANIQUES DES ALLIAGES ALUMINIUM-CUIVRE (Al-Cu)

In order to master and improve the quality and properties of the final products, the major industrial challenge lies in the possibility of controlling the morphology, size of microstructures that reside within the molded pieces, as well as their defects; this is the fundamental reason according to which we are more and more interested in mastering the growth and germination of such alloys, as well as the developing structures, at the time of solidification process. The modeling reveals as a valuable aid in the mastery of the formation of such heterogeneousness: segregation cells that are incompatible with industrial requirements. The whole work focuses upon the modeling of the segregation phenomenon of the four hypoeutectic alloys, Al1%Cu, Al2%Cu, Al3%Cu et Al4%Cu, as well as the copper effect upon certain mechanical properties of aluminum. Usually, the microstructure and mechanical behavior of such alloys as Al-Cu are directly influenced by some parameters such as composition, cooling velocity and homogenization process

Accessing elite nurses for research: reflections on the theoretical and practical issues of telephone interviewing

Elite groups are interesting as they frequently are powerful (in terms of position, knowledge and influence) and enjoy considerable authority. It is important, therefore, to involve them in research concerned with understanding social contexts and processes. This is particularly pertinent in healthcare, where considerable strategic development and change are features of everyday practice that may be guided or perceived as being guided, by elites. This paper evolved from a study investigating the availability and role of nurses whose remit involved leading nursing research and development within acute NHS Trusts in two health regions in Southern England. The study design included telephone interviews with Directors of Nursing Services during which time the researchers engaged in a reflective analysis of their experiences of conducting research with an `elite' group. Important issues identified were the role of gatekeepers, engagement with elites and the use of the telephone interview method in this context. The paper examines these issues and makes a case for involving executive nurses in further research. The paper also offers strategies to help researchers design and implement telephone interview studies successfully to maximise access to the views and experiences of `hard to reach groups', such as elites, while minimising the associated disruption

Signs and symptoms of suspected myocardial ischemia in women: Results from the what is the optimal method for ischemia evaluation in women? Trial

Background: Much of our understanding of gender differences in chest pain was derived from noncontemporary reports. The aim of the current report was to compare the frequency of chest pain by measures of ischemia in 824 women with suspected myocardial ischemia prospectively enrolled in a clinical trial of exercise testing with electrocardiography (ETT-ECG) alone compared to myocardial perfusion single photon emission computed tomography (SPECT) (ETT-MPS). Methods: Women seeking evaluation of chest pain or anginal equivalent symptoms were randomized to ETT-ECG or ETT-MPS with Tc-99m tetrofosmin. The Women\u27s Ischemia Syndrome Evaluation (WISE) and Seattle Angina Questionnaire (SAQ) chest pain and Duke Activity Status Index (DASI) questionnaires were employed in enrolled women. Higher SAQ scores denote improved symptoms or functioning. Results: Eight hundred twenty-four women, average age 63 years, at intermediate-high coronary artery disease (CAD) likelihood were enrolled from 43 North American centers. Traditional cardiac risk factors were prevalent, with nearly half of women having a family history of premature coronary disease, hypertension, and hyperlipidemia. Chest pain symptoms occurring at least one to three times per week were reported in 60% of women. An examination of the SAQ domains revealed that although women reported minimal physical limitations (median, interquartile range [IQR] 88, 75-100), there was a greater frequency of stable chest pain symptoms (median, IQR=40, 30-50). The majority of women (79%) reported moderate to heavy physical activity levels at home, with the average ETT and DASI estimated metabolic equivalents (METs) of 8.6±2.6 and 11.5±3.8. Women with more frequent daily episodes of chest pain were more likely to have a lower Duke Treadmill Score (DTS), 1 or mm of ST segment depression, and an abnormal MPS. Conclusions: The current report details a contemporary evaluation of female-specific symptomatology and measures of myocardial ischemia. Women reporting frequent angina were more likely to exhibit ischemia and this may characterize a female-specific typical angina pattern. © 2011 Copyright, Mary Ann Liebert, Inc