Ion engine thrust vector study, phase 2 Quarterly report

Performance prediction for expected thrust misalignment in electron bombardment ion thruste

Ion engine thrust vector study

Probability of thrust vector misalignment in ion thrustor arra

A redundant arithmetic CORDIC system with a unit scale factor

The CORDIC algorithm for the calculation of trigonometric functions has traditionally suffered from two problems; speed, and the necessity to pre-scale the inputs. The speed problem is overcome to a large extent by the introduction of redundant number systems which have been shown by others. Here we show a new CORDIC system which has a unit scale factor that can be ignored. The unit scale factor is achieved by rotating the vector in 3 dimensional space in a manner which scales its projection onto the X-Y plane by the reciprocal of the overall scale factor. This new technique takes the same number of cycles as the standard CORDIC algorithm, with only marginally slower cycle times than the redundant system of Takagi. The system is shown to be entirely compatible with redundant number system implementations of the CORDIC algorithm

Predicting the cache miss ratio of loop-nested array references

The time a program takes to execute can be massively affected by the efficiency with which it utilizes cache memory. Moreover the cache-miss behavior of a program can be highly unpredictable, in that small changes to input parameters can cause large changes in the number of misses. In this paper we present novel analytical models of the cache behavior of programs consisting mainly of array operations inside nested loops, for direct-mapped caches. The models are used to predict the miss-ratios of three example loop nests; the results are shown to be largely within ten percent of simulated values. A significant advantage is that the calculation time is proportional to the number of array references in the program, typically several orders of magnitude faster than traditional cache simulation methods

Lunar lander conceptual design

This paper is a first look at the problems of building a lunar lander to support a small lunar surface base. A series of trade studies was performed to define the lander. The initial trades concerned choosing number of stages, payload mass, parking orbit altitude, and propellant type. Other important trades and issues included plane change capability, propellant loading and maintenance location, and reusability considerations. Given a rough baseline, the systems were then reviewed. A conceptual design was then produced. The process was carried through only one iteration. Many more iterations are needed. A transportation system using reusable, aerobraked orbital transfer vehicles (OTV's) is assumed. These OTV's are assumed to be based and maintained at a low Earth orbit (LEO) space station, optimized for transportation functions. Single- and two-stage OTV stacks are considered. The OTV's make the translunar injection (TLI), lunar orbit insertion (LOI), and trans-Earth injection (TEI) burns, as well as midcourse and perigee raise maneuvers

Ion engine thrust vector study Quarterly report

Ion beam current and direction changes due to electrode misalignment, and analysis of electrode temperature distribution and thermal stresses in ion engine thrust vecto

Story-Making: A Narrative Pedagogy For Transformative Christian Faith

Thesis advisor: Thomas H. GroomeThe mid-twentieth century upsurge in scholarship on the methodological and conceptual importance of narrative for theology - established in the work of H.R. Niebuhr, Hans Frei and Stephen Crites inter alia - was a watershed moment for narrative pedagogy in Christian religious education. By and large, narrative approaches have however tended to privilege one form of narrative embodiment - literary (or discursive narratives) - over action (or non-discursive narratives). This dissertation points to the equivocal and pluriform nature of narrativity, and its codification in much more than oral and written textuality. I extend it to refer to a distinct competency for establishing a meaningful world (or ethos) to inhabit, which congeals in varied forms of human expression including our lived narratives. Narrative competency allows us to understand ourselves as persons and communities in (synchronic) relationship with the rest of creation, as well as in (diachronic) relation with persons and communities from the past and in the anticipated future. I propose a narrative pedagogy for transformative faith based on the concept of story-making, which draws on this expanded understanding of narrativity. My story-making approach is grounded in Christian praxis that aims to establish the experiential matrix that, through the working of God's grace, invites and aids the re-storying of the learner's life. Story-making also has as its vision narrative historic praxis that incarnates in social action the understanding that human subjectivity is lived in responsible agency in the present, retrieving the memory of suffering and possibility from the past, in the hope of a more just future. This dissertation is inspired by the Caribbean heritage of survival and grace-filled possibility, but ultimately extrapolates for universal wisdom. It is sustained by a belief that Christian religious education is about forming disciples with agency for furthering the Great story of the reign of God in history and society. The creative, even poetic, enterprise of Caribbean existence is iconic of this existential challenge that remains ubiquitous for life in the modern globalized economy.Thesis (PhD) — Boston College, 2013.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Religious Education and Pastoral Ministry

So happy for your loss: Consumer schadenfreude increases choice satisfaction

Consumers often feel schadenfreude, an emotion reflecting an experience of pleasure over misfortunes of another. Schadenfreude has found wide use in advertising, but its actual consequences for consumers have not been thoroughly documented. The present research investigates the effect of schadenfreude on consumers' satisfaction with choices they have made. Building on the feelings‐as‐information theory, the authors posit that consumers take their positive feelings of schadenfreude over another's unrelated bad purchase as positive information about their own choices, and through such misattribution become more satisfied with their own choices. Three experiments show that feeling schadenfreude over another consumer's bad purchase makes consumers more satisfied with their own choices (Study 1), regardless of whether the other's bad purchase is in the same or in a different product category as one's own choice (Study 2), but only so long as consumers are not aware that they are engaging in misattribution (Study 3). The present research contributes to the literature on schadenfreude and feelings‐as‐information theory. Its findings may be used by marketers aiming to exert an unconscious influence on consumer satisfaction

The Influence of Dormitory Architecture On Resident Behavior

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66943/2/10.1177_001391657300500402.pd