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Displaying 27051 - 27075 of 74178

Earthquakes, Hurricanes, Floods, Every Day Failures and 1500 Miles of Levee - Risk Analysis Experiences and Lessons

October 1, 2009
Author(s)
Martin W. McCann , Said Salah-Mars, Jerry L. Foster, Gregory B. Baecher, Robert C. Patev, Harvey W. Jones, Therese P. McAllister
By the first quarter of 2006, two risk studies of major levee systems (over 1500 miles of levee) in the U.S. were underway. The IPET Risk and Reliability Analysis was a retrospective analysis and the DRMS was a prospective analysis intended to support

Electronic Vector-Network-Analyzer Verification

October 1, 2009
Author(s)
Dylan F. Williams, Arkadiusz C. Lewandowski, Denis X. LeGolvan, Ronald A. Ginley
The National Institute of Standards and Technology (NIST) has just introduced a fully electronic measurement verification system for microwave vector-network-analyzer (VNA) calibrations called NISTeVerify. The system allows you to quickly verify VNA

Fitting Spheres to Range Data from 3D Imaging Systems

October 1, 2009
Author(s)
Marek Franaszek, Geraldine S. Cheok, Kamel S. Saidi, Christoph J. Witzgall
Two error functions used for nonlinear Least Squares (LS) fitting of spheres to range data from 3D imaging systems are discussed: orthogonal error function and directional error function. Both of the functions allow unrestricted gradient-based minimization

From the Editor's Desk: Why We Are Here

October 1, 2009
Author(s)
Catherine A. Remley
This is an Editorial for the October, 2009 issue of IEEE Microwave Magazine. Kate Remley, the Editor-in-Chief, writes about timely topics for the members of the Microwave Theory and Techniques Society (MTT-S).

Influence of room temperature control system on AFM imaging

October 1, 2009
Author(s)
Joseph Fu, Wei Chu, Theodore V. Vorburger
As technology progresses, the control of environment for experiments is also getting more sophisticated; such as the control of lab temperature and vibration. Temperature controlled within ± 0.25° C for a general purpose lab is common place. We illustrate

Measuring the EUV-induced contamination rates of TiO2-capped multilayer optics by anticipated production-environment hydrocarbons

October 1, 2009
Author(s)
Shannon B. Hill, Nadir S. Faradzhev, Charles S. Tarrio, Thomas B. Lucatorto, Robert A. Bartynski, B. V. Yakshinskiy, T. E. Madey
The primary, publicly reported cause of optic degradation in pre-production extreme-ultraviolet (EUV) lithography systems is carbon deposition. This results when volatile organics adsorb onto optic surfaces and then are cracked by EUV-induced reactions

Relative Photon-to-Carrier Efficiencies of Alternating Nanolayers of Zinc Phthalocyanine and C60 Multilayer Films Assessed by Time-Resolved Terahertz Spectroscopy

October 1, 2009
Author(s)
Okan Esenturk, Joseph S. Melinger, Paul A. Lane, Edwin J. Heilweil
Alternating multi-layer and 1:1 blended films of zinc phthalocyanine (ZnPc)and buckminsterfullerene (C60) were investigated as model active layers for solar cells by Time-Resolved Terahertz Spectroscopy (TRTS). Relative photon-to-carrier efficiencies 2

Size Measurement of Nanoparticles using Atomic Force Microscopy

October 1, 2009
Author(s)
Jaroslaw Grobelny, Frank W. DelRio, Pradeep Namboodiri, Doo-In Kim, Vincent A. Hackley, Robert F. Cook
In this assay protocol, procedures for dispersing gold nanoparticles on various surfaces such that they are suitable for imaging and height measurement via intermittent contact mode AFM are first described. The procedures for AFM calibration and operation

Spectrum Simulation in DTSA-II

October 1, 2009
Author(s)
Nicholas W. Ritchie
Spectrum simulation is a useful practical and pedagogical tool. Particularly with complex samples or trace constituents, a simulation can help to understand the limits of the technique and how to optimize the tools for the optimal measurement. DTSA-II

Submillimeter Spectrum and Analysis of Vibrational and Hyperfine Coupling Effects in (HI)2

October 1, 2009
Author(s)
Laurent H. Coudert, Sergei P. Belov, F. Willaert, B. McElmurry, R. Lucchese, John W. Bevan, Jon T. Hougen
Observed rotational-vibrational transitions of HI dimer in the geared bending mode, centered at 511.9 GHz, are reported. This 50 kHz high resolution spectrum was recorded using a co-axially configured pulsed jet submillimeter spectrometer and the hyperfine

The coefficient of thermal expansion of highly enriched 28Si

October 1, 2009
Author(s)
Ernest G. Kessler Jr., Guido Bartl, Arnold Nicolaus, Rene Schodel, Peter Becker
For the new definition of the SI-unit mass based on a fundamental constant, a redetermination of Avogadro s constant is the goal of an international collaboration of numerous national laboratories and universities. Since a relative uncertainty of about 2

The Dimensional Markup Language Specification for Inspection Results Data

October 1, 2009
Author(s)
William G. Rippey
The Dimensional Markup Language (DML) specification defines a data model and Extensible Model Language (XML) encoding rules for dimensional inspection results for discrete parts. To support manufacturing quality assurance processes, DML results files are

Traceable waveform calibration with a covariance-based uncertainty analysis

October 1, 2009
Author(s)
Paul D. Hale, Dylan F. Williams, Andrew M. Dienstfrey, Arkadiusz C. Lewandowski, Tracy S. Clement, Darryl A. Keenan
We describe a method for calibrating the voltage that a step-like pulse generator produces at a load at every time point in themeasured waveform. The calibration includes an equivalent-circuit model of the generator that can be used to determine how the

Uncertainty of timebase corrections

October 1, 2009
Author(s)
Chih-Ming Wang, Paul D. Hale, Dylan F. Williams
We develop a covariance matrix describing the uncertainty of a new timebase for waveform measurements determined with the National Institute of Standards and Technology's timebase correction algorithm. This covariance matrix is used with covariance

Update on DMIS Certification

October 1, 2009
Author(s)
William G. Rippey
The Dimensional Standards Consortium (DMSC) and the National Institute of Standards and Technology (NIST) announced the rollout of the DMSC's DMIS Certification Program at the International Manufacturing Technology Show (IMTS), September 2008. The

Vibration-induced PM and AM noise in microwave components

October 1, 2009
Author(s)
Archita Hati, Craig W. Nelson, David A. Howe
The performance of microwave components is sensitive to vibrations to some extent. Among them, microwave cables and connectors, bandpass filters, mechanical phase shifters and some non-linear components are the most sensitive. The local oscillator is one

Virtual Testing of Concrete Transport Properties

October 1, 2009
Author(s)
Dale P. Bentz, Edward J. Garboczi, Nicos Martys, Kenneth A. Snyder, W. S. Guthrie, Konstantinos Kyritsis, Narayanan Neithalath
The transport properties of concrete are critical to its field performance. Commonly encountered degradation mechanisms are dependent on ionic diffusivity, sorptivity, and permeability. In this paper, virtual testing of two of these concrete transport

Water Absorption in Internally Cured Mortar Made with Water-Filled Lightweight Aggregate

October 1, 2009
Author(s)
Ryan Henkensiefken, Javier Castro, Dale P. Bentz, Tommy Nantung, Jason Weiss
The increased propensity for shrinkage cracking in low w/c concrete has spawned the development of new technologies that can reduce the risk of early-age cracking. One of these is internal curing. Internal curing uses saturated lightweight aggregate to
Displaying 27051 - 27075 of 74178