10,248 research outputs found
Boundary layer relaminarization device
Relamination of a boundary layer formed in supersonic flow over the leading edge of a swept airfoil is accomplished by means of at least one band, especially a quadrangular band, and most preferably a square band. Each band conforms to the leading edge and the upper and lower surfaces of the airfoil as an integral part thereof and extends perpendicularly from the leading edge. Each band has a height of about two times the thickness of the maximum expected boundary layer
INCREASING OUR EFFECTIVENESS AS PUBLIC POLICY EDUCATORS
Teaching/Communication/Extension/Profession,
Eta Carinae in the Context of the Most Massive Stars
Eta Car, with its historical outbursts, visible ejecta and massive, variable
winds, continues to challenge both observers and modelers. In just the past
five years over 100 papers have been published on this fascinating object. We
now know it to be a massive binary system with a 5.54-year period. In January
2009, Eta Car underwent one of its periodic low-states, associated with
periastron passage of the two massive stars. This event was monitored by an
intensive multi-wavelength campaign ranging from gamma-rays to radio. A large
amount of data was collected to test a number of evolving models including 3-D
models of the massive interacting winds. August 2009 was an excellent time for
observers and theorists to come together and review the accumulated studies, as
have occurred in four meetings since 1998 devoted to Eta Car. Indeed, Eta Car
behaved both predictably and unpredictably during this most recent periastron,
spurring timely discussions. Coincidently, WR140 also passed through periastron
in early 2009. It, too, is a intensively studied massive interacting binary.
Comparison of its properties, as well as the properties of other massive stars,
with those of Eta Car is very instructive. These well-known examples of evolved
massive binary systems provide many clues as to the fate of the most massive
stars. What are the effects of the interacting winds, of individual stellar
rotation, and of the circumstellar material on what we see as
hypernovae/supernovae? We hope to learn.Comment: 26 pages, 7 figures, IAU General Assembly Joint Discussion on Eta
Carinae in Context of the Most Massive Star
A porous prolate-spheroidal model for ciliated micro-organisms
A fluid-mechanical model is developed for representing the mechanism of propulsion of a finite ciliated micro-organism having a prolate-spheroidal shape. The basic concept is the representation of the micro-organism by a prolate-spheroidal control surface upon which certain boundary conditions on the tangential and normal fluid velocities are prescribed. Expressions are obtained for the velocity of propulsion, the rate of energy dissipation in the fluid exterior to the cilia layer, and the stream function of the motion. The effect of the shape of the organism upon its locomotion is explored. Experimental streak photographs of the flow around both freely swimming and inert sedimenting Paramecia are presented and good agreement with the theoretical prediction of the streamlines is found
POLICY OPTIONS TO FACILITATE CAREER REORIENTATION
Labor and Human Capital,
Etching method for photoresists or polymers
A method for etching or removing polymers, photoresists, and organic contaminants from a substrate is disclosed. The method includes creating a more reactive gas species by producing a plasma discharge in a reactive gas such as oxygen and contacting the resulting gas species with a sacrificial solid organic material such as polyethylene or polyvinyl fluoride, reproducing a highly reactive gas species, which in turn etches the starting polymer, organic contaminant, or photoresist. The sample to be etched is located away from the plasma glow discharge region so as to avoid damaging the substrate by exposure to high energy particles and electric fields encountered in that region. Greatly increased etching rates are obtained. This method is highly effective for etching polymers such as polyimides and photoresists that are otherwise difficult or slow to etch downstream from an electric discharge in a reactive gas
Study on 3GPP Rural Macrocell Path Loss Models for Millimeter Wave Wireless Communications
Little research has been done to reliably model millimeter wave (mmWave) path
loss in rural macrocell settings, yet, models have been hastily adopted without
substantial empirical evidence. This paper studies past rural macrocell (RMa)
path loss models and exposes concerns with the current 3rd Generation
Partnership Project (3GPP) TR 38.900 (Release 14) RMa path loss models adopted
from the International Telecommunications Union - Radiocommunications (ITU-R)
Sector. This paper shows how the 3GPP RMa large-scale path loss models were
derived for frequencies below 6 GHz, yet they are being asserted for use up to
30 GHz, even though there has not been sufficient work or published data to
support their validity at frequencies above 6 GHz or in the mmWave bands. We
present the background of the 3GPP RMa path loss models and their use of odd
correction factors not suitable for rural scenarios, and show that the
multi-frequency close-in free space reference distance (CI) path loss model is
more accurate and reliable than current 3GPP and ITU-R RMa models. Using field
data and simulations, we introduce a new close-in free space reference distance
with height dependent path loss exponent model (CIH), that predicts rural
macrocell path loss using an effective path loss exponent that is a function of
base station antenna height. This work shows the CI and CIH models can be used
from 500 MHz to 100 GHz for rural mmWave coverage and interference analysis,
without any discontinuity at 6 GHz as exists in today's 3GPP and ITU-R RMa
models.Comment: To be published in 2017 IEEE International Conference on
Communications (ICC), Paris, France, May 201
A high-throughput mass spectrometric assay for discovery of human lipoxygenase inhibitors and allosteric effectors.
Lipoxygenases (LOXs) regulate inflammation through the production of a variety of molecules whose specific downstream effects are not entirely understood due to the complexity of the inflammation pathway. The generation of these biomolecules can potentially be inhibited and/or allosterically regulated by small synthetic molecules. The current work describes the first mass spectrometric high-throughput method for identifying small molecule LOX inhibitors and LOX allosteric effectors that change the substrate preference of human lipoxygenase enzymes. Using a volatile buffer and an acid-labile detergent, enzymatic products can be directly detected using high-performance liquid chromatography-mass spectrometry (HPLC-MS) without the need for organic extraction. The method also reduces the required enzyme concentration compared with traditional ultraviolet (UV) absorbance methods by approximately 30-fold, allowing accurate binding affinity measurements for inhibitors with nanomolar affinity. The procedure was validated using known LOX inhibitors and the allosteric effector 13(S)-hydroxy-9Z,11E-octadecadienoic acid (13-HODE)
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