Astrophysical Axion Bounds

Axion emission by hot and dense plasmas is a new energy-loss channel for stars. Observational consequences include a modification of the solar sound-speed profile, an increase of the solar neutrino flux, a reduction of the helium-burning lifetime of globular-cluster stars, accelerated white-dwarf cooling, and a reduction of the supernova SN 1987A neutrino burst duration. We review and update these arguments and summarize the resulting axion constraints.Comment: Contribution to Axion volume of Lecture Notes in Physics, 20 pages, 3 figure

Phase transformations of alpha-Al₂O₃ during annealing in a reducing atmosphere

Study results of corundum structure transformations due to annealing of a-AI₂О₃ in Ar atmosphere containing a reducing component (СО + Н₂) at 1700-1900 ℃ are presented. It has been found that a polycrystalline layer containing new phases is formed at the single crystal surface during the annealing under a high evaporation rate. One of those phases belongs to the AI₂О₃ cubic syngony (spinel) while another one has hexagonal structure (P63/mmc space group). А qualitative model has been proposed for the observed a-AI₂О₃ ➔ AIAI₂О₄ (spinel) transformation involving the hexagonal phase.Представлено результати дослiджень трансформацiї структури корунду в результатi вiдпалу a-AI₂О₃ в атмосферi Ar з вiдновними компонентами (СО + Н₂) при температурi 1700-1900 ℃. Встановлено, що на поверхнi монокристалiчних зразкiв на фонi високої швидкостi випару при вiдпалi утворюється полiкристалiчний шар, що мiстить новi фази. Одна з виявлених фаз вiдноситься до кубiчної сингонiї Fd3M (шпiнель), iнша - має гексагональну структуру (просторова група P63/mmc). 3апропоновано якiсну модель перетворення a-AI₂О₃ ➔ AIAI₂О₄ (шпiнель) за участю гексагональної фази.Представлены результаты исследований трансформации структуры корунда в результате отжига a-AI₂О₃ в атмосфере Ar с восстановительной компонентой (СО + Н₂) при температуре 1700-1900 ℃. Установлено, что на поверхности монокристаллических образцов на фоне высокой скорости испарения при отжиге образуется поликристаллический слой, содержащий новые фазы. Одна из обнаруженных фаз относится к кубической сингонии Fd3M (шпинель), другая - имеет гексагональную структуру (пространственная группа P63/mmc). Предложена качественная модель наблюдаемого превращения a-AI₂О₃ ➔ AIAI₂О₄ (шпинель) с участием гексагональной фазы

Enhancements in Functionality of the Interactive Visual Explorer for ATLAS Computing Metadata

The development of the Interactive Visual Explorer (InVEx), a visual analytics tool for the computing metadata of the ATLAS experiment at LHC, includes research of various approaches for data handling both on server and client sides. InVEx is implemented as a web-based application which aims at the enhancing of analytical and visualization capabilities of the existing monitoring tools and facilitates the process of data analysis with the interactivity and human supervision. The current work is focused on the architecture enhancements of the InVEx application. First, we will describe the user-manageable data preparation stage for cluster analysis. Then, the Level-of-Detail approach for the interactive visual analysis will be presented. It starts with the low detailing, when all data records are grouped (by clustering algorithms or by categories) and aggregated. We provide users with means to look deeply into this data, incrementally increasing the level of detail. Finally, we demonstrate the development of data storage backend for InVEx, which is adapted for the Level-of-Detail method to keep all stages of data derivation sequence

Enhancements in Functionality of the Interactive Visual Explorer for ATLAS Computing Metadata

The development of the Interactive Visual Explorer (InVEx), a visual analytics tool for ATLAS computing metadata, includes research of various approaches for data handling both on server and client sides. InVEx is implemented as a web-based application which aims at the enhancing of analytical and visualization capabilities of the existing monitoring tools and facilitates the process of data analysis with the interactivity and human supervision. The current work is focused on the architecture enhancements of the InVEx application. First, we will describe the user-manageable data preparation stage for cluster analysis. Then, we will present the Level-of-Detail approach for the interactive visual analysis. It starts with the low detailing, when all data records are grouped (by clustering algorithms or by categories) and aggregated, we provide users with means to look deeply into this data, incrementally increasing the level of detail. And finally, the development of data storage backend for InVEx, which is adapted for the Level-of-Detail method to keep all stages of data derivation sequence

Enhancements in Functionality of the Interactive Visual Explorer for ATLAS Computing Metadata

The development of the Interactive Visual Explorer (InVEx), a visual analytics tool for the computing metadata of the ATLAS experiment at LHC, includes research of various approaches for data handling both on server and client sides. InVEx is implemented as a web-based application which aims at the enhancing of analytical and visualization capabilities of the existing monitoring tools and facilitates the process of data analysis with the interactivity and human supervision. The current work is focused on the architecture enhancements of the InVEx application. First, we will describe the user-manageable data preparation stage for cluster analysis. Then, the Level-of-Detail approach for the interactive visual analysis will be presented. It starts with the low detailing, when all data records are grouped (by clustering algorithms or by categories) and aggregated. We provide users with means to look deeply into this data, incrementally increasing the level of detail. Finally, we demonstrate the development of data storage backend for InVEx, which is adapted for the Level-of-Detail method to keep all stages of data derivation sequence