20,009 research outputs found
A Hands-On, Active Learning Approach to Increasing Manufacturing Knowledge in Engineering Students
This paper describes a new learning module implemented as part of the senior capstone design course at Marquette University to teach engineering students about basic manufacturing processes, lean manufacturing principles, and design for manufacturability. The module includes several examples of active and student centered learning as part of an in-class assembly line simulation exercise. Students reflected on this experience, and suggested process improvements to save time, reduce cost and waste, and improve the assembly line process. They learned of the importance of manufacturing documentation, process design, and design for assembly. At the end of the module, students understood the importance of designing a product not only for the end user, but also for the assemblers and inspectors. Details of the module design and implementation will be presented along with comments from students
Evidence of Skyrmion excitations about in n-Modulation Doped Single Quantum Wells by Inter-band Optical Transmission
We observe a dramatic reduction in the degree of spin-polarization of a
two-dimensional electron gas in a magnetic field when the Fermi energy moves
off the mid-point of the spin-gap of the lowest Landau level, . This
rapid decay of spin alignment to an unpolarized state occurs over small changes
to both higher and lower magnetic field. The degree of electron spin
polarization as a function of is measured through the magneto-absorption
spectra which distinguish the occupancy of the two electron spin states. The
data provide experimental evidence for the presence of Skyrmion excitations
where exchange energy dominates Zeeman energy in the integer quantum Hall
regime at
Ion composition and drift observations in the nighttime equatorial ionosphere
The first in situ measurements of ion composition in the nighttime equatorial E and F region ionospheres (90-300 km) are presented and discussed. These profiles were obtained by two rocket-borne ion mass spectrometers launched from Thumba, India on March 9-10, 1970 at solar zenith angles of 112 deg and 165 deg. Ionosonde data established that the composition was measured at times bounding a period of F region downward drift. During this period the ions O(+) and N(+) were enhanced by one to three orders of magnitude between 220 and 300 km. Below the drift region (200 km), O(+) ceased to be the major ionic constituent, but the concentrations of O(+) and N(+) remained larger than predicted from known radiation sources and loss processes. Here also, both the O2(+) and NO(+) profiles retained nearly the same shape and magnitude throughout the night in agreement with theories assuming scattered UV radiation to be the maintaining source. Light metallic ions including Mg(+), Na(+) and possibly Si(+) were observed to altitude approaching 300 km, while the heavier ions Ca(+) and K(+) were seen in reduced quantity to 200 km. All metal ion profiles exhibited changes which can be ascribed to vertical drifting
On the Existence of Radiation Gauges in Petrov type II spacetimes
The radiation gauges used by Chrzanowski (his IRG/ORG) for metric
reconstruction in the Kerr spacetime seem to be over-specified. Their
specification consists of five conditions: four, which we treat here as valid
gauge conditions, plus an additional condition on the trace of the metric
perturbation. In this work, we utilize a newly developed form of the perturbed
Einstein equations to establish a condition -- on a particular tetrad component
of the stress-energy tensor -- under which the full IRG/ORG can be imposed.
Using gauge freedom, we are able to impose the full IRG for Petrov type II and
type D backgrounds, using a different tetrad for each case. As a specific
example, we work through the process of imposing the IRG in a Schwarzschild
background, using a more traditional approach. Implications for metric
reconstruction using the Teukolsky curvature perturbations in type D spacetimes
are briefly discussed.Comment: 21 pages, uses iop style files. v2: proved a stronger result for type
II backgrounds, added a subsection on remaining gauge freedom in the full IRG
and improved calrity and readability throughout due to insightful referee
comments; published as Class. Quantum Grav. 24 (2007) 2367-238
The ILR School at Fifty: Voices of the Faculty, Alumni & Friends (Full Text)
A collection of reflections on the first fifty years of the School of Industrial and Labor Relations at Cornell University. Compiled by Robert B. McKersie, J. Gormly Miller, Robert L. Aronson, and Robert R. Julian. Edited by Elaine Gruenfeld Goldberg. It was the hope of the compilers that the reflections contained in this book would both kindle memories of the school and stimulate interest on the part of future generations of ILRies who have not yet shared in its special history.
Dedicated to the Memory of J. Gormly Miller, 1914-1995.
Copyright 1996 by Cornell University. All rights reserved
Design of a fault tolerant airborne digital computer. Volume 2: Computational requirements and technology
This final report summarizes the work on the design of a fault tolerant digital computer for aircraft. Volume 2 is composed of two parts. Part 1 is concerned with the computational requirements associated with an advanced commercial aircraft. Part 2 reviews the technology that will be available for the implementation of the computer in the 1975-1985 period. With regard to the computation task 26 computations have been categorized according to computational load, memory requirements, criticality, permitted down-time, and the need to save data in order to effect a roll-back. The technology part stresses the impact of large scale integration (LSI) on the realization of logic and memory. Also considered was module interconnection possibilities so as to minimize fault propagation
Multi-objective evolutionary–fuzzy augmented flight control for an F16 aircraft
In this article, the multi-objective design of a fuzzy logic augmented flight controller for a high performance fighter jet (the Lockheed-Martin F16) is described. A fuzzy logic controller is designed and its membership functions tuned by genetic algorithms in order to design a roll, pitch, and yaw flight controller with enhanced manoeuverability which still retains safety critical operation when combined with a standard inner-loop stabilizing controller. The controller is assessed in terms of pilot effort and thus reduction of pilot fatigue. The controller is incorporated into a six degree of freedom motion base real-time flight simulator, and flight tested by a qualified pilot instructor
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