Slip ring experience in long duration space applications

Ball Aerospace experience with slip rings in space extends back to 1962. Over 40 multi-ring assemblies have been flown and continuous operating lifetimes greater than 8 years at up to 60 rpm have been demonstrated. Slip rings provide multi-channel transfer of electrical power and signals in assemblies that are small in size and weight, and low in cost. By use of multiple brushes and sufficient copper within the assembly, power transfer efficiency better than 99.95 percent for high voltage circuits can be achieved. A low slip ring failure rate based on actual space operation totalling billions of ring revolutions has been established. Well qualified suppliers who have been making slip rings for space use for over 25 years are available. It is hoped that the suspected problem in SEASAT will not be allowed to prejudice space system designer against these very useful mechanisms

Anatomy of a bearing torque problem

In the early 1970s, an antenna despin drive was developed for MBB solar science satellite HELIOS. A problem with high bearing drag torque that was encountered on the two flight models of this drive, after successful tests were completed on twelve bearings, an engineering model, and the qualification unit is discussed

African American Adolescent Males\u27 Experiences within the Education System: Implications for School Counseling Practice

This article examines the literature on the experiences of African American adolescent males in the education system. The primary focus of the article is to explore the following: historical accounts dating back to the transatlantic slavery era; Disciplinary Disparities within the education system Postsecondary opportunities. Implications for counselor education and practice are discussed. The author concludes with recommendations to improve the experiences of African American adolescent males within the educational system

Rationale for tau aggregation inhibitor therapy in Alzheimer's disease and other tauopathies

Preprin

On the path to AI

This open access book explores machine learning and its impact on how we make sense of the world. It does so by bringing together two ‘revolutions’ in a surprising analogy: the revolution of machine learning, which has placed computing on the path to artificial intelligence, and the revolution in thinking about the law that was spurred by Oliver Wendell Holmes Jr in the last two decades of the 19th century. Holmes reconceived law as prophecy based on experience, prefiguring the buzzwords of the machine learning age—prediction based on datasets. On the path to AI introduces readers to the key concepts of machine learning, discusses the potential applications and limitations of predictions generated by machines using data, and informs current debates amongst scholars, lawyers and policy makers on how it should be used and regulated wisely. Technologists will also find useful lessons learned from the last 120 years of legal grappling with accountability, explainability, and biased data