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Displaying 43501 - 43525 of 74036

The Revision of Standard 62: What a Difference a Decade Makes

June 1, 2002
Author(s)
Andrew K. Persily
The American Society of heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has been revising Standard 62,Ventilation for Acceptable Indoor Air Quality since 1991. The two primary motivations for this revision have been 1) to convert the

Thermodynamic Quantities for the Ionization Reactions of Buffers

June 1, 2002
Author(s)
Robert N. Goldberg, N Kishore, R M. Lennen
This review contains selected values of thermodynamic quantities for the aqueous ionization reactions of 63 buffers, many of which are used in biological research. Since the aim is to be able to predict values of the ionization constant at temperatures not

Understanding Part Fabrication Errors in Closed-Loop Machining Systems

June 1, 2002
Author(s)
Herbert T. Bandy, Lawrence A. Welsch
This paper presents an analysis of part fabrication errors (part dimension and form deviations) in closed-loop machining systems. Modeling methods are used to situate error components in the context of other error components to clarify the effects of error

Understanding the U.S. National Standards System

June 1, 2002
Author(s)
K J. Johnsen
This article, intended for publication in German in Germany, clarifies attributes of the U.S.standards system and its similarities and differences with European and international counterparts. In the United States, standardization is essentially a free

Unraveling the Symmetry of the Hole States Near the Fermi Level in the MgB 2 Superconductor

June 1, 2002
Author(s)
Y Zhu, A R. Moodenbaugh, G Schneider, J W. Davenport, T Vogt, Q Li, G Gu, Daniel A. Fischer, J Tafto
We use x-ray absorption spectroscopy (XAS) and electron energy loss spectroscopy (EELS) to study the near edge fine structure at the K-edge of boron in the superconductor M gB 2. We observe in XAS a peak of width 0.6 eV at the threshold of this K-edge

Using a High-Value Resistor in Single-Electron Counting Measurements

June 1, 2002
Author(s)
Randolph Elmquist, Neil M. Zimmerman, William Huber
An experiment using a high-value cryogenic resistor is proposed, with the aim of improving the experimental link between three quantum electrical standards. This technique is new in its approach and does not require feedback from either a voltage detector

Using a High-Value Resistor in Triangle Comparisons of Electrical Standards

June 1, 2002
Author(s)
Randolph Elmquist, Neil M. Zimmerman, William Huber
We propose an experiment with some advantages over other direct quantum metrology triangle comparisons. First, by using a cryogenic resistor that can be calibrated, the QHR standard needs to be used only for short periods. Second, the experiment does not

Vibrational Population Control in Liquid-Phase Metal Carbonyls

June 1, 2002
Author(s)
V D. Kleiman, Joseph S. Melinger, Edwin J. Heilweil
Broadband picosecond and femtosecond mid-infrared chirped-pulse excitation with broadband probe techniques are being explored at NIST using multi-element, mid-infrared focal plane array detectors. Ultrafast infrared chirped IR pulse generation, detection

Video Transmission for 3G Mobile Communication Systems

June 1, 2002
Author(s)
Hamid Gharavi, K Ban
This paper presents the design and implementation of a mobile ad-hoc network for video communications. The network architecture is based on cluster-to-cluster operation using IEEE 802.11b FHSS (Frequency Hopping Spread Spectrum). FHSS is considered to

Whisker Formation on Electroplated Sn-Cu

June 1, 2002
Author(s)
Maureen E. Williams, C E. Johnson, Kil-Won Moon, Gery R. Stafford, C A. Handwerker, William J. Boettinger
The probability of whisker growth on as-deposited tin (Sn) electrodeposits has been measured as a function of copper (Cu superscript2+) addition to a commercial bright methanesulfonate electrolyte. Two substrate materials were used: free standing 250 um

Control Strategies for APACTS Micro-Macro-Manipulator Integration

May 31, 2002
Author(s)
Richard J. Norcross
The Carderock Division of the Naval Surface Warfare Center is developing the Automated Paint Application, Containment, and Treatment System (APACTS). APACTS will apply anti-corrosive and anti-fouling paints to ship hulls in an environmentally sound manner

Improved 1 kHz Capacitance Calibration Uncertainty

May 30, 2002
Author(s)
Anne-Marie Jeffery, Andrew D. Koffman
Uncertainties for 1 kHz capacitance calibrations have been decreased at the National Institute of Standards and Technology (NIST). The improvements are based on frequency-dependence characterization from 1592 Hz to 1 kHz. The relevant measurements and the

Kinetic Spanning Trees for Minimum-Power Routing in MANETS

May 30, 2002
Author(s)
Camillo Gentile, R E. Van Dyck
A distributed kinetic spanning tree algorithm is proposed for routing in wireless mobile ad hoc networks. Assuming a piecewise linear motion model for the nodes, the sequence of shortest-path spanning trees is determined, valid until the time of the next

Airflow and Aerosol Transport Modeling in Hart Senate Office Building

May 23, 2002
Author(s)
Steven J. Emmerich, Cynthia H. Reed, Andrew K. Persily
A modeling study of airflow and contaminant transport in the Hart Senate Office Building (HSOB) was performed to obtain insight into the transport of anthrax spores within the building after a short-term release in October 2001. This analysis employed an

NIST's High-Speed Pulse Parameter Measurement Service

May 21, 2002
Author(s)
Nicholas Paulter, Donald R. Larson
The National Institute of Standards and Technology (NIST) provides a me surement service, number 65200S, "Fast Repetitive Pulse Transition Parameters," for measuring the impulse response of high-speed (transition durations > 7 ps) samplers and the output

Sensitivity of Display Reflection Measurements to Apparatus Geometry

May 21, 2002
Author(s)
Edward F. Kelley
Reflection measurements made upon electronic displays can suffer from non-reproducibility owing to their possible strong dependence upon apparatus geometry. The geometrical dependence arises from non-Lambertian diffusion properties. We show the

Bounds on Permittivity Calculations using a TE 01d Dielectric Resonator

May 20, 2002
Author(s)
Jerzy Krupka, Kristof Derzakowski, Billy F. Riddle, James R. Baker-Jarvis, Robert N. Clarke, A. Abramowicz, O. C. Rochard
The use of both mode-matching and Rayleigh-Ritz numerical techniques for complex permittivity calculations using a TE 01δ mode dielectric resonator allows the determination of lower and upper bounds of the permittivity. The maximum difference of the

Calibration of Broadband RF Field Probes Using a Coaxial Transmission Line

May 20, 2002
Author(s)
Claude Weil, David R. Novotny, Robert T. Johnk, Arthur Ondrejka
We discuss a new broadband (10MHz to 40 GHz) RF field standard to be used for calibrating electrically-small electromagnetic field probes. The technique generates a well-defined and uniform TEM mode fields between the conductors of an air-filled coaxial

Crossover from First-Order to Critical Wetting in Methanol on Alkanes

May 20, 2002
Author(s)
J O. Indekeu, A I. Posazhennikova, David J. Ross, D Bonn, J Meunier
A mean-field theory is presented which describes the basic observations of recent experiments revealing rich wetting behaviour of n-alkane/methanol mixtures at the liquid-vapour interface. The theory is based on a microscopic lattice-gas model from which a
Displaying 43501 - 43525 of 74036
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