Apparatus for measuring electric field strength on the surface of a model vehicle Patent

Space environment simulation system for measuring spacecraft electric field strength in plasma sheat

Research on ion beam diagnostics Final report

Research on ion beam diagnostic

Interaction Between Ion Beams and Plasmas

Interaction between low energy cesium ion beam and thermal cesium plasm

Surge current and electron swarm tunnel tests of thermal blanket and ground strap materials

The results are described of a series of current conduction tests with a thermal control blanket to which grounding straps have been attached. The material and the ground strap attachment procedure are described. The current conduction tests consisted of a surge current examination of the ground strap and a dilute flow, energetic electron deposition and transport through the bulk of the insulating film of this thermal blanket material. Both of these test procedures were used previously with thermal control blanket materials

Interaction Between Ion Beams and Plasmas

Stability limits for ion acoustic waves due to interaction between low energy cesium ion beam and thermal cesium plasm

Operation of solar cell arrays in dilute streaming plasmas

Operation of solar cell arrays in dilute streaming plasma

At least some errors are randomly generated (Freud was wrong)

An experiment was carried out to expose something about human error generating mechanisms. In the context of the experiment, an error was made when a subject pressed the wrong key on a computer keyboard or pressed no key at all in the time allotted. These might be considered, respectively, errors of substitution and errors of omission. Each of seven subjects saw a sequence of three digital numbers, made an easily learned binary judgement about each, and was to press the appropriate one of two keys. Each session consisted of 1,000 presentations of randomly permuted, fixed numbers broken into 10 blocks of 100. One of two keys should have been pressed within one second of the onset of each stimulus. These data were subjected to statistical analyses in order to probe the nature of the error generating mechanisms. Goodness of fit tests for a Poisson distribution for the number of errors per 50 trial interval and for an exponential distribution of the length of the intervals between errors were carried out. There is evidence for an endogenous mechanism that may best be described as a random error generator. Furthermore, an item analysis of the number of errors produced per stimulus suggests the existence of a second mechanism operating on task driven factors producing exogenous errors. Some errors, at least, are the result of constant probability generating mechanisms with error rate idiosyncratically determined for each subject

Ion beam plume and efflux characterization flight experiment study

A flight experiment and flight experiment package for a shuttle-borne flight test of an 8-cm mercury ion thruster was designed to obtain charged particle and neutral particle material transport data that cannot be obtained in conventional ground based laboratory testing facilities. By the use of both ground and space testing of ion thrusters, the flight worthiness of these ion thrusters, for other spacecraft applications, may be demonstrated. The flight experiment definition for the ion thruster initially defined a broadly ranging series of flight experiments and flight test sensors. From this larger test series and sensor list, an initial flight test configuration was selected with measurements in charged particle material transport, condensible neutral material transport, thruster internal erosion, ion beam neutralization, and ion thrust beam/space plasma electrical equilibration. These measurement areas may all be examined for a seven day shuttle sortie mission and for available test time in the 50 - 100 hour period

Investigation of ion beam diagnostics final report

Ion beam diagnostics - plasma wind tunnel stream generation and characteristics, mercury optical resonance probe, environment effects on ion stream neutralization, and electric field meter

Computing a largest empty anchored cylinder, and related problems

Let $S$ be a set of $n$ points in $R^d$, and let each point $p$ of $S$ have a positive weight $w(p)$. We consider the problem of computing a ray $R$ emanating from the origin (resp.\ a line $l$ through the origin) such that $\min_{p\in S} w(p) \cdot d(p,R)$ (resp. $\min_{p\in S} w(p) \cdot d(p,l)$) is maximal. If all weights are one, this corresponds to computing a silo emanating from the origin (resp.\ a cylinder whose axis contains the origin) that does not contain any point of $S$ and whose radius is maximal. For $d=2$, we show how to solve these problems in $O(n \log n)$ time, which is optimal in the algebraic computation tree model. For $d=3$, we give algorithms that are based on the parametric search technique and run in $O(n \log^5 n)$ time. The previous best known algorithms for these three-dimensional problems had almost quadratic running time. In the final part of the paper, we consider some related problem