Determining the physical limits on semi‐active control performance: a tutorial

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106822/1/stc1602.pd

Average Cross-Sectional Area of DebriSat Fragments Using Volumetrically Constructed 3D Representations

Debris fragments from the hypervelocity impact testing of DebriSat are being collected and characterized for use in updating existing satellite breakup models. One of the key parameters utilized in these models is the ballistic coefficient of the fragment which is directly related to its areatomass ratio. However, since the attitude of fragments varies during their orbital lifetime, it is customary to use the average crosssectional area in the calculation of the areatomass ratio. The average crosssectional area is defined as the average of the projected surface areas perpendicular to the direction of motion and has been shown to be equal to onefourth of the total surface area of a convex object. Unfortunately, numerous fragments obtained from the DebriSat experiment show significant concavity (i.e., shadowing) and thus we have explored alternate methods for computing the average crosssectional area of the fragments. An imaging system based on the volumetric reconstruction of a 3D object from multiple 2D photographs of the object was developed for use in determining the size characteristic (i.e., characteristics length) of the DebriSat fragments. For each fragment, the imaging system generates N number of images from varied azimuth and elevation angles and processes them using a spacecarving algorithm to construct a 3D point cloud of the fragment. This paper describes two approaches for calculating the average crosssectional area of debris fragments based on the 3D imager. Approach A utilizes the constructed 3D object to generate equally distributed crosssectional area projections and then averages them to determine the average crosssectional area. Approach B utilizes a weighted average of the area of the 2D photographs to directly compute the average crosssectional area. A comparison of the accuracy and computational needs of each approach is described as well as preliminary results of an analysis to determine the "optimal" number of images needed for the 3D imager to accurately measure the average cross sectional area of objects with known dimensions

Validity of the new lifestyles NL-1000 accelerometer for measuring time spent in moderate-to-vigorous physical activity in school settings

Current interest in promoting physical activity in the school environment necessitates an inexpensive, accurate method of measuring physical activity in such settings. Additionally, it is recognized that physical activity must be of at least moderate intensity in order to yield substantial health benefits. The purpose of the study, therefore, was to determine the validity of the New Lifestyles NL-1000 (New Lifestyles, Inc., Lee's Summit, Missouri, USA) accelerometer for measuring moderate-to-vigorous physical activity in school settings, using the Actigraph GT1M (ActiGraph, Pensacola, Florida, USA) as the criterion. Data were collected during a cross-country run (n = 12), physical education (n = 18), and classroom-based physical activities (n = 42). Significant and meaningful intraclass correlations between methods were found, and NL-1000 estimates of moderate-to-vigorous physical activity were not meaningfully different from GT1M-estimated moderate- to-vigorous physical activity. The NL-1000 therefore shows promising validity evidence as an inexpensive, convenient method of measuring moderate-to-vigorous physical activity in school settings

Rubrics and Their Use in Inclusive Science

General education teachers are increasingly finding themselves faced with the challenge of providing instruction for all students, including those with learning and behavior problems. Because of the emphasis on experiments and active learning, science classes seem to be one of the most accessible—and accessed—subjects for inclusive programming. However, science instructors are not always as skilled at assessing learning as they are at designing and delivering instruction. A method that can be used to objectively and individually assess the achievement of students with learning and behavior problems is rubrics. When implemented effectively, rubrics can be used to more accurately reflect student achievement and help the educator in determining if remediation is needed.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Reaction Between Nitrogen and Spinel in Chromium

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66029/1/j.1151-2916.1968.tb15671.x.pd

OPEN XAL Status Report 2015

MOPW1050International audienceOpen XAL is an accelerator physics software platformdeveloped in collaboration among several facilitiesaround the world. The Open XAL collaboration wasformed in 2010 to port, improve and extend the successfulXAL platform used at the Spallation Neutron Source foruse in the broader accelerator community and to establishit as the standard platform for accelerator physicssoftware. The site-independent core is complete, activeapplications have been ported, and now we are in theprocess of verification and transitioning to using OpenXAL in production. This paper will present the currentstatus and a roadmap for this project

Sozialstaatliche Kürzungspolitik in Deutschland: Nur eine Mär? Eine quantitative Gesetzgebungsanalyse 1974–2014

Quantitative analyses on welfare state dynamics have to cope with the “dependent variable problem”, as studies on social spending reach different conclusions than analyses of replacement rate data. This article suggests a way around this problem by presenting results from a fine-grained analysis of welfare state legislation in Germany between 1974 and 2014. We show that the German welfare state has seen both cuts and expansions occur in all decades. Moreover, we show by means of a regression analysis that partisan politics play a role. Supporting the “Nixon-in-China”-thesis, social democratic governments are associated with a higher probability of cutbacks – especially in times of budgetary pressure – whereas expansions are more likely under Christian democratic governments

Open XAL status Report 2015

Open XAL is an accelerator physics software platform developed in collaboration among several facilities around the world. The Open XAL collaboration was formed in 2010 to port, improve and extend the successful XAL platform used at the Spallation Neutron Source for use in the broader accelerator community and to establish it as the standard platform for accelerator physics software. The site-independent core is complete, active applications have been ported, and now we are in the process of verification and transitioning to using Open XAL in production. This paper will present the current status and a roadmap for this project