15,005 research outputs found
The Guns of Fort Lee
No full textIn September, the defenses were further extended with square earthworks and bastions. Washington hoped that Fort Lee and Fort Washington would effectively block the Hudson River to the British Ships. He also sank ships in the river to further block the British Fleet.
The night of November 19-20, 1776, the British Forces commanded by Lieutenant General Earl Cornwallis crossed the Hudson River and landed beneath the Palisades about five miles from Fort Lee. Washington was forced to abandon the form and retreat. Most of the American supplies and artillery had to be left behindOriginal file name Fort Lee Historical Park The Guns at Fort Lee (1).jp
The meander line antenna for Bluetooth
No full textThis Letter proposes a novel antenna that has a small size and high gain features. The conventional chip antennas are made of very high dielectric materials that result in small size but inherently low radiation gain. Instead of using the dielectric materials, the proposed antenna has a small size while retaining high gain. The bandwidth and gain of this model, with antenna size 15 X 10 X 6 mm, have 9.0% (at 2.44 GHz, \S-11\ less than or equal to -10 dB) and 2.73 dBi, respectively. (C) 2002 Wiley Periodicals, Inc
Bow-tie wide-band monopole antenna with the novel impedance-matching technique
No full textA staircase bow-tie monopole-type antenna that features a novel broadband technique is investigated experimentally and numerically. A bandwidth of 77.1% (VSWRless than or equal to2) can be achieved, and an omnidirectional radiation pattern is obtained. The electrical characteristics of the proposed antenna make it attractive,tar use in multiband mobile systems. (C) 2002 Wiley Periodicals, Inc
Metabolic engineering of Escherichia coli for the production of medium-chain-length polyhydroxyalkanoates rich in specific monomers
No full textThe Escherichia coli fabG(Ec) gene and the Pseudomonas aeruginosa rhlG(Pa) gene, which encode 3-ketoacyl-acyl carrier protein reductase, were expressed in E. coli W3110 and its fadA mutant strain WA101 to examine their roles in medium-chain-length (MCL) polyhydroxyalkanoate (PHA) biosynthesis from fatty acids. When one of these 3-ketoacyl-acyl carrier protein reductase genes was co-expressed with the Pseudomonas sp. 61-3 PHA synthase gene (phaC2(Ps)) in E. coli W3110, MCL-PHA composed mainly of 3-hydroxyoctanoate and 3-hydroxydecanoate was synthesized from sodium decanoate. When the fabG(Ec) gene and the phaC2(Ps) gene were co-expressed in the fadA mutant E. coli strain WA101, MCL-PHA rich in 3-hydroxydecanoate monomer up to 93 mol% was accumulated from sodium decanoate. This was possible by efficiently redirecting 3-ketoacyl-coenzymes A from the beta-oxidation pathway to the PHA biosynthesis pathway without losing two carbon units, the strategy of which can be extended for the production of MCL-PHAs rich in other specific monomers. (C) 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.This work was supported by the National Research
Laboratory Program (2000-N-NL-01-C-237) of the Korean
Ministry of Science and Technology (MOST). We
thank Dr. Y. Doi and Dr. Isabelle-S. Hinner for kindly
providing us with plasmid pBSEB50 and pBBR1MCS,
respectively. We also thank Dr. G.M. Church for the
kind gift of plasmid pKO3
Application of JP-8 in a heavy duty diesel engine
No full textAn experimental study was carried out to investigate the combustion and emission of JP-8 and diesel fuel in an optically-accessible single-cylinder heavy duty diesel engine equipped with a high pressure common-rail injection system in order to evaluate the feasibility of JP-8 application in diesel engine. The basic spray characteristics, including spray tip penetration and spray angle, were investigated with macroscopic spray images obtained by the Mie-scattering method. The combustion and emission characteristics were analyzed on the basis of the results obtained from the spray experiments. Visualization by direct imaging was used to characterize the combustion process. It was found that JP-8 had a shorter spray tip penetration and wider spray angle than diesel fuel mainly due to the faster vaporization characteristic of JP-8. The peak heat release rate was higher and the pre-mixed burn portion was larger with JP-8 due to its superior mixing rate through faster vaporization characteristics. Furthermore, ignition delay with JP-8 was longer than that with diesel fuel due to the lower cetane number of JP-8. In terms of emission, JP-8 showed a benefit in smoke reduction while it produced larger amounts of HC and NO(x). Longer ignition delay and accelerated oxidation in the late stage of JP-8 combustion were verified by direct imaging. (C) 2011 Elsevier Ltd. All rights reserved
Dynamic electrophoresis of a spherical dispersion of soft particles subject to a stress-jump condition
No full textComplex time series modeling and analysis for rotor dynamics identification
No full textA new time series method, directional ARMAX (dARMAX) model-based approach, is proposed for rotor dynamics identification. The dARMAX processes complex-varied signals, utilizing the complex modal resting theory which enables the separation of the backward and forward modes in the two-sided frequency domain and makes effective modal parameter identification possible, to account for the dynamic characteristics inherent in rotating machinery. The dARMAX is superior in nature to the conventional ARMAX particularly in the estimation of the modal parameters for isotropic and weakly anisotropic rotors. Numerical simulations are performed to demonstrate effectiveness of the dARMAX
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