Phase Stability under Irradiation of Precipitates and Solid Solutions in Model ALloys and in ODS Alloys Relevant for Gen IV

The overall objective of this program is to investigate the irradiation-altered phase stability of oxide precipitates in ODS steels and of model alloy solid solutions of associated systems. This information can be used to determine whether the favorable mechanical propertiies of these steels are maintained under irradiation, thus addressing one of the main materials research issues for this class of steels as identified by the GenIV working groups. The research program will also create fundamental understanding of the irradiation precipitation/dissolution problem by studying a "model" system in which the variables can be controlled and their effects understood individually

Practical management of anticoagulation in patients with atrial fibrillation.

Anticoagulation for atrial fibrillation has become more complex due to the introduction of new anticoagulant agents, the number and kinds of patients requiring therapy, and the interactions of those patients in the matrix of care. The management of anticoagulation has become a team sport involving multiple specialties in multiple sites of care. The American College of Cardiology, through the College\u27s Anticoagulation Initiative, convened a roundtable of experts from multiple specialties to discuss topics important to the management of patients requiring anticoagulation and to make expert recommendations on issues such as the initiation and interruption of anticoagulation, quality of anticoagulation care, management of major and minor bleeding, and treatment of special populations. The attendees continued to work toward consensus on these topics, and present the key findings of this roundtable in a state-of- the-art review focusing on the practical aspects of anticoagulation care for the patient with atrial fibrillation

Bubble formation and growth in glasses

In this study, we simulated gas bubble formation in glasses by in-situ ion implantation. Alkali silicate glass and Na-borosilicate glass were implanted in situ with 50 keV Xe ions at temperatures at 200°C in a Hitachi-9000 electron microscope. Bubble formation was studied by transmission electron microscopy images taken during interruptions of the ion beam after discrete implanted-ion dose steps. We present a possible mechanism of bubble formation and growth based on amorphous network structures

Radiation damage from single heavy ion impacts on metal surfaces

The effects of single ion impacts on the surfaces of films of Au, Ag, In and Pb have been studied using in-situ transmission electron microscopy. On all these materials, individual ion impacts produce surface craters, in some cases, with associated expelled material. The cratering efficiency scales with the density of the irradiated metal. For very thin Au foils, in some cases individual ions are seen to punch small holes completely through the foil. Continued irradiation result in a thickening of the foil. The process giving rise to crater and hole formation and other changes observed in the thin foils has been found to be due to pulsed localized flow - i.e. melting and flow due to the thermal spikes arising form individual ion impacts. Experiments carried out on thin films of sliver sandwiched between SiO2 layers have indicated that pulsed localized flow also occurs in this system and contributes to the formation of Ag nanoclusters in SiO2 - a system of interest for its non-linear optical properties. Calculation indicates that, when ion-induced, collision cascades occur near surfaces with energy densities sufficient to cause melting, craters are formed. Crater formation occurs as a result of the explosive outflow of material from the hot molten core of the cascade. Processes occurring in the sandwiched layer are less well understood