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Displaying 26 - 50 of 51

Progress Towards SI Traceable Force Metrology for Nanomechanics

January 1, 2004
Author(s)
David B. Newell, Eric P. Whitenton, John A. Kramar, Jon R. Pratt, Douglas T. Smith
This paper is based, in its entirety, on NIST-approved publications: Calibration of Piezoresistive Cantilever Force Sensors Using the NIST Electrostatic Force Balance, The NIST Electrostatic Force Balance Experiment, The NIST Microforce Realization and

Progress Towards Systeme International d'Unites Traceable Force Metrology for Nanomechanics

January 1, 2004
Author(s)
Jon R. Pratt, Douglas T. Smith, David B. Newell, John A. Kramar, Eric P. Whitenton
Recent experiments with the National Institute of Standards and Technology (NIST) Electrostatic Force Balance (EFB) have achieved agreement between an electrostatic force and a gravitational force of 10^(-5) N to within a few hundred pN/¿N. This result

Effects of Different Whiskers on the Reinforcement of Dental Resin Composites

July 1, 2003
Author(s)
Hockin D. Xu, Janet Quinn, Douglas T. Smith, Anthony A. Giuseppetti, F Eichmiller
Objective: Whiskers were recently used to reinforce dental composites to extend their use to large stress-bearing restorations. The aim of this study was to investigate the effects of different types of whiskers on composite properties. It was hypothesized

The NIST Microforce Realization and Measurement Project

April 1, 2003
Author(s)
David B. Newell, Edwin R. Williams, John A. Kramar, Jon R. Pratt, Douglas T. Smith
The National Institute of Standards and Technology (NIST) has launched a five-year Micro-force Realization and Measurement project focusing on the development of an instrument and laboratory capable of realizing and measuring the SI unit of force below

Compact Force Sensors for Low-Force Mechanical Probe Calibration

September 1, 2002
Author(s)
Jon R. Pratt, Douglas T. Smith, S Woody
The loading mechanisms of instrumented indentation machines are often calibrated using deadweights. In many cases, due to the geometry of the loading frame, the applied deadweight is tensile, while the indentation leads to be measured are compressive. In

Compact Force Sensors for Low-Force Mechanical Probe Calibration

June 1, 2002
Author(s)
Douglas T. Smith, S Woody, Jon R. Pratt
The loading mechanisms of instrumented indentation machines are often calibrated using deadweights. In many cases, due to the geometry of the loading frame, the applied deadweight is tensile, while the indentation leads to be measured are compressive. In

The NIST Microforce Realization and Measurement Project

June 1, 2002
Author(s)
David B. Newell, Jon R. Pratt, John A. Kramar, Douglas T. Smith, Edwin R. Williams
The National Institute of Standards and Technology (NIST) has launched a five-year Microforce Realization and Measurement project focusing on the development of an instrument and laboratory capable of realizing and measuring the SI unit of force below

The NIST Microforce Realization and Measurement Project

June 1, 2002
Author(s)
David B. Newell, Jon R. Pratt, John A. Kramar, Douglas T. Smith, Edwin R. Williams
The National Institute of Standards and Technology (NIST) has launched a five-year Micro-force Realization and Measurement project focusing on the development of an instrument and laboratory capable of realizing and measuring the SI unit of force below

Effect of Thermal Cycling on Whisker-Reinforced Dental Resin Composites

January 1, 2002
Author(s)
H H. Xu, F Eichmiller, Douglas T. Smith, Gary E. Schumacher, Anthony A. Giuseppetti, Joseph M. Antonucci
The mechanical properties of dental resin composites needs to be improved in order to extend their use to high stress-bearing applications such as crown and bridge restorations. Recent studies used single crystal ceramic whiskers to reinforce dental

SI Traceability of Force at the Nanonewton Level

July 1, 2001
Author(s)
David B. Newell, Jon R. Pratt, John A. Kramar, Douglas T. Smith, L. A. Feeney, Edwin R. Williams
Although nanonewton force measurements are commonplace in industry, no National Measurement Institute supports a link to the International System of Units (SI) below one newton. The National Institute of Standards and Technology has launched a five-year

Towards a Traceable Nanoscale Force Standard

May 1, 2001
Author(s)
Jon R. Pratt, David B. Newell, Edwin R. Williams, Douglas T. Smith, John A. Kramar
The National Institute of Standards and Technology has launched a five-year project to traceably link the International System of Units (SI) to forces between 10 -8N and 10 -2N. In this paper, we give a background and overview of this project, discuss the

Dental Resin Composites Containing Silica-Fused Whiskers: Effects of Whisker-to-Silica Ratio on Fracture Toughness and Indentation Properties

April 1, 2001
Author(s)
Hockin D. Xu, Janet Quinn, Douglas T. Smith, Joseph M. Antonucci, Gary E. Schumacher, F Eichmiller
Dental resin composites need to be strengthened in order to improve their performance in large stress-bearing applications such as crowns and multiple-unit restorations. Recently, silica-fused ceramic whiskers were used to reinforce dental composites, and

Hysteresis and Related Error Mechanisms in the NIST Watt Balance Experiment

February 16, 2001
Author(s)
J. Schwarz, Ruimin Liu, David B. Newell, Richard L. Steiner, Edwin R. Williams, Douglas T. Smith, A Erdemir, J Woodford
The NIST Watt Balance experiment is being completely rebuilt after its 1998 determination of the SI Volt and Planck's constant. That measurement yielded a result with approximately 1 x 10 -7 standard relative uncertainty. Because the goal of the new

SI Traceability of Force at the Nanonewton Level

January 1, 2001
Author(s)
David B. Newell, Jon R. Pratt, John A. Kramar, Douglas T. Smith, L Feeney, Edwin R. Williams
Although nanonewton force measurements are commonplace in industry, no National Measurement Institute supports a link to the International System of Units (SI) below one newton. The National Institute of Standards and Technology has launched a five-year

Vortex Pinning in Microindented Yba 2 Cu 3 O 7-x Single Crystals

August 1, 2000
Author(s)
Marina Turchinskaya, Douglas T. Smith, Alexander L. Roytburd, Debra L. Kaiser
A high resolution magneto-optical technique with a magnetic indicator film was used to study the effect of a regular array of micrometer-sized mechanical indentations on magnetization dynamics at the surface of a twinned single crystal of Yba 2Cu 3O 7-δ as

Indentation Modulus and Hardness of Whisker-Reinforced Heat-Cured Dental Resin Composites

January 1, 2000
Author(s)
H H. Xu, Douglas T. Smith, Gary E. Schumacher, F Eichmiller, Joseph M. Antonucci
Recent studies showed that ceramic whisker reinforcement imparted a nearly two-fold increase in the strength of dental resin composites. The aim of the study was to investigate the indentation response and measure the elastic modulus hardness, and