9,138 research outputs found
Smaug the Magnificent: A Critical Analysis of J.R.R. Tolkien’s Anarcho-monarchism
For all of the political machinations at work in The Lord of the Rings, there is astonishingly little detail paid to political institutions in it or any of J.R.R. Tolkien’s works. Although readers may use such resources as The Lord of the Rings’ monolithic series of appendices to trace the names and deeds of kings back to the Elder Days, the author has surprisingly little to say about how governments throughout Middle-earth actually function; so much attention is paid to the figure who occupies the throne that little to no description is provided as to what kingship actually entails in Tolkien’s world. In a universe where rulers are the primary actors, this seems like a striking omission
Labor Guide to Labor Law
[Excerpt] This book is a practical guide to labor law in the private sector. The first 8 chapters present a discussion of legal principles primarily based on the Labor Management Relations Act (LMRA), 1947, as amended, commonly referred to as the “Act.” The remaining chapters discuss principles based on the Labor Management Reporting and Disclosure Act and the Civil Rights Act of 1964, as amended, as well as on the LMRA
Grand Challenges of Traceability: The Next Ten Years
In 2007, the software and systems traceability community met at the first
Natural Bridge symposium on the Grand Challenges of Traceability to establish
and address research goals for achieving effective, trustworthy, and ubiquitous
traceability. Ten years later, in 2017, the community came together to evaluate
a decade of progress towards achieving these goals. These proceedings document
some of that progress. They include a series of short position papers,
representing current work in the community organized across four process axes
of traceability practice. The sessions covered topics from Trace Strategizing,
Trace Link Creation and Evolution, Trace Link Usage, real-world applications of
Traceability, and Traceability Datasets and benchmarks. Two breakout groups
focused on the importance of creating and sharing traceability datasets within
the research community, and discussed challenges related to the adoption of
tracing techniques in industrial practice. Members of the research community
are engaged in many active, ongoing, and impactful research projects. Our hope
is that ten years from now we will be able to look back at a productive decade
of research and claim that we have achieved the overarching Grand Challenge of
Traceability, which seeks for traceability to be always present, built into the
engineering process, and for it to have "effectively disappeared without a
trace". We hope that others will see the potential that traceability has for
empowering software and systems engineers to develop higher-quality products at
increasing levels of complexity and scale, and that they will join the active
community of Software and Systems traceability researchers as we move forward
into the next decade of research
Study of orifice fabrication technologies for the liquid droplet radiator
Eleven orifice fabrication technologies potentially applicable for a liquid droplet radiator are discussed. The evaluation is focused on technologies capable of yielding 25-150 microns diameter orifices with trajectory accuracies below 5 milliradians, ultimately in arrays of up to 4000 orifices. An initial analytical screening considering factors such as trajectory accuracy, manufacturability, and hydrodynamics of orifice flow is presented. Based on this screening, four technologies were selected for experimental evaluation. A jet straightness system used to test 50-orifice arrays made by electro-discharge machining (EDM), Fotoceram, and mechanical drilling is discussed. Measurements on orifice diameter control and jet trajectory accuracy are presented and discussed. Trajectory standard deviations are in the 4.6-10.0 milliradian range. Electroforming and EDM appear to have the greatest potential for Liquid Droplet Radiator applications. The direction of a future development effort is discussed
Formation of Cosmic Dust Bunnies
Planetary formation is an efficient process now thought to take place on a
relatively short astronomical time scale. Recent observations have shown that
the dust surrounding a protostar emits more efficiently at longer wavelengths
as the protoplanetary disk evolves, suggesting that the dust particles are
coagulating into fluffy aggregates, "much as dust bunnies form under a bed."
One poorly understood problem in this coagulation process is the manner in
which micron-sized, charged grains form the fractal aggregate structures now
thought to be the precursors of protoplanetary disk evolution. This study
examines the characteristics of such fractal aggregates formed by the collision
of spherical monomers and aggregates where the charge is distributed over the
aggregate structure. The aggregates are free to rotate due to collisions and
dipole-dipole electrostatic interactions. Comparisons are made for different
precursor size distributions and like-charged, oppositelycharged, and neutral
grains
Aqueous-Based Extrusion Fabrication of Ceramics on Demand
Aqueous-Based Extrusion Fabrication is an additive manufacturing technique that
extrudes ceramic slurries of high solids loading layer by layer for part fabrication. The
material reservoir in a previously developed system has been modified to allow for
starting and stopping of the extrusion process on demand. Design pros and cons are
examined and a comparison between two material reservoir designs is made. Tests are
conducted to determine the optimal deposition parameters for starting and stopping the
extrudate on demand. The collected test data is used for the development of a deposition
strategy that improves material deposition consistency, including reduced material
buildup at sharp corners. Example parts are fabricated using the deposition strategy and
hardware design.Mechanical Engineerin
The role of sign in students' modeling of scalar equations
We describe students revising the mathematical form of physics equations to
match the physical situation they are describing, even though their revision
violates physical laws. In an unfamiliar air resistance problem, a majority of
students in a sophomore level mechanics class at some point wrote Newton's
Second Law as F = -ma; they were using this form to ensure that the sign of the
force pointed in a direction consistent with the chosen coordinate system while
assuming that some variables have only positive value. We use one student's
detailed explanation to suggest that students' issues with variables are
context-dependent, and that much of their reasoning is useful for productive
instruction.Comment: 5 pages, 1 figure, to be published in The Physics Teache
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