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Publications

Search Publications by Jolene D. Splett

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Displaying 26 - 50 of 56

Correlation Between the Pressure Dependence of the Critical Temperature and the Reversible Strain Effect on the Critical Current and Pinning Force in Bi 2 Sr 2 CaCu 2 O 8+x Wires

December 16, 2011
Author(s)
Xifeng Lu, Loren F. Goodrich, Daniel C. van der Laan, Jolene D. Splett, Najib Cheggour, T G. Holesinger, F J. Baca
Bi2Sr2CaCu2O8+x round wires are among the most promising high-temperature superconductor candidates for making high-field magnets that operate at fields above 20 Tesla. Owing to the brittle nature of high-temperature superconductors, their electro

Method for determining the irreversible strain limit of Nb 3 Sn wires

June 6, 2011
Author(s)
Loren F. Goodrich, Najib Cheggour, Xifeng Lu, Jolene D. Splett, Theodore C. Stauffer, Bernard J. Filla
We have defined a rigorous and reliable method for determining the irreversible strain limit of Nb3Sn wires. The critical current (Ic) is measured as a function of applied longitudinal strain (ε), Ic(ε), at one magnetic field and a temperature of 4.0 K

Strain and Magnetization Properties of High Subelement Count Tube-type Nb3Sn Strands

June 6, 2011
Author(s)
Najib Cheggour, X Peng, E Gregory, M Tomsic, M D. Sumption, A. K. Ghosh, Xifeng Lu, Theodore C. Stauffer, Loren F. Goodrich, Jolene D. Splett
Abstract—A tubular technique for economical production of Nb3Sn material with large numbers of subelements is being explored by Supergenics I LLC and Hyper Tech Research Inc. The number of subelements was increased to 919 (744 subelements plus 175 Cu

Use of Electronic Calibration Units for Vector-Network-Analyzer Verification

July 30, 2010
Author(s)
Dylan F. Williams, Arkadiusz C. Lewandowski, Denis X. LeGolvan, Ronald A. Ginley, Chih-Ming Wang, Jolene D. Splett
We present measurements indicating that electronic calibration units are stable enough to be used in place of mechanical vector-network-analyzer verification artifacts. This enables a new fully automated approach to verifying microwave vector-network

Influence of Ti and Ta doping on the irreversible strain limit of ternary Nb 3 Sn superconducting wires made by the restacked-rod process

April 1, 2010
Author(s)
Najib Cheggour, Loren F. Goodrich, Theodore C. Stauffer, Jolene D. Splett, Xifeng Lu, A. K. Ghosh, G. Ambrosio
Nb3Sn superconducting wires made with restacked-rod process (RRP®) were found to have a dramatically improved resilience to axial tensile strain when alloyed with Ti as compared to Ta. Whereas Ta-alloyed Nb3Sn in RRP wires showed permanent damage to its

Charpy Machine Verification: Limits and Uncertainty

September 1, 2008
Author(s)
Jolene D. Splett, Christopher N. McCowan, Chih-Ming Wang
The purpose of this document is to clarify some issues pertaining to uncertainty statements and the ASTM E 23 limits used in the Charpy machine verification program. We explain some of the distributional subtleties associated with uncertainty and

Dynamic Force Measurement: Instrumented Charpy Impact Testing

January 1, 2008
Author(s)
Christopher N. McCowan, Jolene D. Splett, E. Lucon
The maximum forces measured by the machines in this round robin are in good agreement. This general result shows that the static force calibration of instrumented strikers is quite robust, and that the various striker designs evaluated here performed in a

An Empirical Model for the Warm-Up Drift of a Commercial Harmonic Phase Standard

June 1, 2007
Author(s)
Jeffrey A. Jargon, Jolene D. Splett, Dominic F. Vecchia, Donald C. DeGroot
We develop an empirical model for the warm-up drift in a harmonic phase standard used to calibrate the phase distortion of a nonlinear vector network analyzer. The model enables us to estimate the time at which the standard reaches stability.

Current Ripple Effect on n-Value

June 1, 2007
Author(s)
Loren F. Goodrich, Jolene D. Splett
We studied the systematic effect of current ripple on the determination of n-value, which is the index of the shape of the electric field-current (E-I) curve. Commercial Nb3Sn wires were measured with controlled amounts of ac ripple. Substitution-box

Evaluation Specimens for Izod Impact Machines (SRM 2115): Report of Analysis

October 1, 2006
Author(s)
Thomas A. Siewert, Jolene D. Splett, Raymond L. Santoyo
In the past few years, we have received a number of requests for verification specimens for Izod impact machines, similar to what we offer for Charpy impact machines. Although there are similarities between Izod and Charpy impact testing, there are some

International Comparison of Impact Reference Materials (2004)

April 3, 2006
Author(s)
Christopher N. McCowan, G. Roebben, Y. Yamaguchi, S. Lefrancois, Jolene D. Splett, S. Takagi, A. Lamberty
A three-year horizontal comparison has been completed between national laboratories that certify specimens for the indirect verification of Charpy impact test machines. The participants in this study were the Institute for Reference Materials and

Analysis of Charpy impact verification data: 1993-2003

March 1, 2006
Author(s)
Jolene D. Splett, Christopher N. McCowan
Indirect verification tests, used to verify the performance of Charpy impact machines according to ASTM Standard E23, are evaluated by the National Institute of Standards and Technology (NIST) and the data from these tests are co1lected in a database. The

Relative Permittivity and Loss Tangent Measurement Using the NIST 60 mm Cylindrical Cavity

September 1, 2005
Author(s)
Michael D. Janezic, Jolene D. Splett, Kevin J. Coakley, Raian K. Kaiser, John H. Grosvenor Jr
In order to develop a dielectric Standard Reference Material (SRM), a measurement system for measuring the relative permittivity and loss tangent of dielectric materials is presented. To achieve the necessary level of measurement accuracy, we selected the

Unexpected Effect of Field Angle in Magnetoresistance Measurements of High-Purity Nb

June 1, 2005
Author(s)
Loren F. Goodrich, Theodore C. Stauffer, Jolene D. Splett, Dominic F. Vecchia
We report on unexpected field-angle dependence of the magnetoresistance measurements of commercial, high-purity Nb discovered during our study of residual resistivity ratio (RRR) measurements. The (RRR) value indicates the purity and the low-temperature

Uncertainty in Reference Values for the Charpy V-notch Verification Program

May 1, 2005
Author(s)
Jolene D. Splett, Chih-Ming Wang
We present a method for computing the combined standard uncertainty for reference values used in the Charpy machine verification program administered by the National Institute of Standards and Technology. The technique is compliant with the ISO GUM and

Nonlinear Modeling of Tunnel Diode Detectors

September 24, 2004
Author(s)
Dave K. Walker, Kevin J. Coakley, Jolene D. Splett
We investigate the sensitivity and nonlinear properties of a tunnel diode microwave detector as functions of the input power and the load impedance presented at the detector's output. We compare the two-tone method estimate of nonlinearity with precise

Measuring residual resistivity ratio of high-purity Nb

July 27, 2004
Author(s)
Loren F. Goodrich, Theodore C. Stauffer, Jolene D. Splett, Dominic F. Vecchia
We compared methods of measuring the residual resistivity ratio (RRR) of high-purity Nb using transport current. Our experimental study is intended to answer some fundamental questions about the best measurement for RRR and the biases that may exist among

Modeling Warm-Up Drift in Commercial Harmonic Phase Standards

July 2, 2004
Author(s)
Jeffrey A. Jargon, Jolene D. Splett, Dominic F. Vecchia, Donald C. DeGroot
We develop an empirical model for the warm-up drift of harmonic phase standards that are used to calibrate the phase distortion of nonlinear vector nrtworks analyzers. This model will enable us to estimate the time at which the standards reach stability.

Estimation of Q-Factors and Resonant Frequencies

March 1, 2003
Author(s)
Kevin J. Coakley, Jolene D. Splett, Michael D. Janezic, R F. Kaiser
We estimate the quality factor Q and resonant frequency fo of a microwave cavity based on resonance curve observations on an equally-spaced frequency grid. The observed resonance curve is the squared magnitude of an observed complex scattering parameter

Estimation of Q-factors and Resonant Factors

March 1, 2003
Author(s)
Kevin J. Coakley, Jolene D. Splett, Michael D. Janezic, Raian K. Kaiser
We estimate the quality factor Q and resonant frequency f0 of a microwave cavity based on resonance curve observations on an equally-spaced frequency grid. The observed resonance curve is the squared magnitude of an observed complex scattering parameter