Solid motor diagnostic instrumentation

A review of typical surveillance and monitoring practices followed during the flight phases of representative solid-propellant upper stages and apogee motors was conducted to evaluate the need for improved flight diagnostic instrumentation on future spacecraft. The capabilities of the flight instrumentation package were limited to the detection of whether or not the solid motor was the cause of failure and to the identification of probable primary failure modes. Conceptual designs of self-contained flight instrumentation packages capable of meeting these reqirements were generated and their performance, typical cost, and unit characteristics determined. Comparisons of a continuous real time and a thresholded hybrid design were made on the basis of performance, mass, power, cost, and expected life. The results of this analysis substantiated the feasibility of a self-contained independent flight instrumentation module as well as the existence of performance margins by which to exploit growth option applications

Entwicklung einer laminaren Grenzschicht hinter einer Absaugestelle

Memorandum presenting an investigation of boundary-layer suction and its favorable effect in deferring transition points as long as possible in order to avoid turbulence

Global patterns of β-diversity along the phylogenetic time-scale : the role of climate and plate tectonics

Aim: We aimed to assess the relative influence of the historical and contemporary processes determining global patterns of current \u3b2-diversity. Specifically, we quantified the relative effects of contemporary climate and historical plate tectonics on \u3b2-diversity at different phylogenetic scales. Location: Global. Time Period: Contemporaneous. Major taxa studied: Mammals and birds. Methods: We analysed the current \u3b2-diversity patterns of birds and mammal assemblages at sequential depths in the phylogeny, that is, from the tips to deeper branches. This was done by slicing bird and mammal phylogenetic trees into 66 time slices of 1 Ma (from 0 to 65 Ma) and recording the branches within each slice. Using global distribution data, we defined the branches\u2019 geographical distribution as the union of the corresponding downstream species distributions. For each time slice, we (a) computed pairwise \u3b2-diversity across all the grid cells for the whole world and (b) estimated the correlation between this \u3b2-diversity matrix and contemporary climatic and geographical distances, and past geological distances, a proxy for plate tectonics. Results: Contemporary climate best explained the \u3b2-diversity of shallow branches (i.e., species). For mammals, the geographical isolation of landmasses generated by plate tectonics best explained the \u3b2-diversity of deeper branches, whereas the effect of past isolation was weaker for birds. Main conclusions: Our study shows that the relative influence of contemporary climate and plate tectonics on the \u3b2-diversity of bird and mammal assemblages varies along the phylogenetic time-scale. Our phylogenetic time-scale approach is general and flexible enough to be applied to a broad spectrum of study systems and spatial scales

Rapid Quantification of Soilborne Pathogen Communities in Wheat-based Long-term Field Experiments

This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by The American Phytopathological Society and can be found at: https://doi.org/10.1094/PDIS-09-15-1020-RERainfed experiments operated continuously for up to 84 years in semiarid eastern Oregon are among the oldest agronomic trials in North America. Disease incidence and severity had been quantified visually but quantification of inoculum density had not been attempted. Natural inoculum of 17 fungal and nematode pathogens were quantified for each of two years on eight trials using DNA extracts from soil. Crop type, tillage, rotation, soil fertility and year, and their interactions, had large effects on the pathogens. Fusarium culmorum and Pratylenchus thornei were more dominant than F. pseudograminearum and P. neglectus where spring crops were grown, and the opposite species dominances occurred where winter wheat was the only crop. Bipolaris sorokiniana and Phoma pinodella were restricted to presence of spring cereals and pulse crops, respectively. Helgardia spp. occurred in winter wheat-fallow rotations but not in annual winter wheat. Gaeumannomyces graminis var. tritici was more prevalent in cultivated than in non-cultivated soils and the opposite generally occurred for Rhizoctonia solani AG-8. Densities of Pythium spp. Clade F were high but were also influenced by treatments. Significant treatment effects and interactions were more prevalent in two long-standing (> 50 yr) annually cropped experiments (29%) than two long-standing 2-yr wheat-fallow rotations (14%). Associations among pathogens occurred mostly in an 84-yr-old annual cereals experiment. This survey provided guidance for research on dynamics of root-infecting pathogens of rainfed field crops and identified two pathogens (D. tritici-repentis and Phoma pinodella) not previously identified at the location

Experimental limits on nucleon decay and ΔB=2 processes

Results from the IMB collabration to detect possible proton decay in a salt mine near Cleveland, Ohio are presented. Detection apparatus is described.(AIP)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87900/2/1_1.pd

The search for proton decay

Following a very brief description of the theoretical developments which motivated the search for proton decay, I shall describe one of these experiments (the IMB experiment) in some detail. Then I shall compare recent results from that experiment with those from other detectors.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87399/2/321_1.pd

IMB Detector‐The first 30 Days

A large water Chernekov detector, located 2000 feet below ground, has recently been turned on. The primary purpose of the device is to measure nucleon stability to limits 100 times better than previous measurements. The properties of the detector are described along with its operating characteristics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87428/2/138_1.pd

The IMB photomultiplier test facility

An automatic system for testing up to 32 photomultiplier tubes (PMs) simultaneously under single photon counting conditions has been used to measure characteristics of more than 2500 PMs for use in the Irvine-Michigan-Brookhaven (IMB) proton decay experiment, 2048 tubes (64 EMI 9834B 8" diameter, and 1984 EMI 9870B 5" diameter) were selected for use in the 8000 m3 IMB water Cherenkov detector, now in operation for over a year. The PM test system is described and results of testing are presented along with PM performance in the IMB detector over the last year. In general, we find that the tube characteristics have smaller fluctuations than expected and that the tubes have proven to be reliable under rugged handling and operating conditions. On the basis of our experience, we make suggestions as to new industry standards for PMs to be used in particle counting.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25571/1/0000113.pd

Defining authorship in user-generated content : copyright struggles in The Game of Thrones

The notion of authorship is a core element in antipiracy campaigns accompanying an emerging copyright regime, worldwide. These campaigns are built on discourses that aim to ‘problematize’ the issues of ‘legality’ of content downloading practices, ‘protection’ for content creators and the alleged damage caused to creators’ livelihood by piracy. Under these tensions, fandom both subverts such discourses, through sharing and production practices, and legitimizes industry’s mythology of an ‘original’ author. However, how is the notion of authorship constructed in the cooperative spaces of fandom? The article explores the most popular fandom sites of A Song of Ice and Fire, the book series that inspires the TV-show Game of Thrones and argues that the notion of authorship is not one-dimensional, but rather consists of attributes that develop across three processes: community building, the creative and the industrial/production process. Here, fandom constructs a figure of the ‘author’ which, although more complex than the one presented by the industry in its copyright/anti-piracy campaigns, maintains the status quo of regulatory frameworks based on the idea of a ‘primary’ creator