scholarly journals Determination of the Boltzmann constant using a quasi-spherical acoustic resonator

2011 ◽  
Vol 369 (1953) ◽  
pp. 4014-4027 ◽  
Author(s):  
Laurent Pitre ◽  
Fernando Sparasci ◽  
Daniel Truong ◽  
Arnaud Guillou ◽  
Lara Risegari ◽  
...  
Keyword(s):  
Molar Mass ◽  
Thermodynamic Temperature ◽  
Standard Uncertainty ◽  
Acoustic Resonator ◽  
Diamond Turning ◽  
Boltzmann Constant ◽  
Triple Point Of Water ◽  
Resonance Frequencies ◽  
Relative Standard

The paper reports a new experiment to determine the value of the Boltzmann constant, , with a relative standard uncertainty of 1.2 parts in 10 6 . k B was deduced from measurements of the velocity of sound in argon, inside a closed quasi-spherical cavity at a temperature of the triple point of water. The shape of the cavity was achieved using an extremely accurate diamond turning process. The traceability of temperature measurements was ensured at the highest level of accuracy. The volume of the resonator was calculated from measurements of the resonance frequencies of microwave modes. The molar mass of the gas was determined by chemical and isotopic composition measurements with a mass spectrometer. Within combined uncertainties, our new value of k B is consistent with the 2006 Committee on Data for Science and Technology (CODATA) value: ( k new B / k B_CODATA −1)=−1.96×10 −6 , where the relative uncertainties are and u r ( k B_CODATA )=1.7×10 −6 . The new relative uncertainty approaches the target value of 1×10 −6 set by the Consultative Committee on Thermometry as a precondition for redefining the unit of the thermodynamic temperature, the kelvin.

scholarly journals The NIST Johnson Noise Thermometry System for the Determination of the Boltzmann Constant

2017 ◽  
Vol 122 ◽  
Author(s):  
Nathan E. Flowers-Jacobs ◽  
Alessio Pollarolo ◽  
Kevin J. Coakley ◽  
Adam C. Weis ◽  
Anna E. Fox ◽  
...  
Keyword(s):  
International System ◽  
Standard Uncertainty ◽  
Boltzmann Constant ◽  
Correlated Noise ◽  
Johnson Noise ◽  
Noise Thermometry ◽  
Relative Standard ◽  
System Of Units ◽  
Johnson Noise Thermometry

In preparation for the redefinition of the International System of Units (SI), five different electronic measurements of the Boltzmann constant have been performed using different Johnson noise thermometry (JNT) systems over the past seven years. In this paper, we describe in detail the JNT system and uncertainty components associated with the most recent National Institute of Standards and Technology (NIST) determination of the Boltzmann constant: k = 1.380642 9(69) × 10−23 J/K, with a relative standard uncertainty of 5.0 × 10−6 and relative offset of −4.05 × 10−6 from the Committee on Data for Science and Technology (CODATA) 2014 recommended value. We discuss the input circuits and the approach we used to match the frequency response of two noise sources. We present new measurements of the correlated noise of the 4 K on-chip resistors in the quantum-accurate, pseudorandom, voltage-noise source, which we used to estimate the correlated, frequency-dependent, nonthermal noise in our system. Finally, we contrast our system with those used in other measurements and speculate on future improvements.

Cylindrical Acoustic Resonator for the Re-determination of the Boltzmann Constant

2010 ◽  
Vol 31 (7) ◽  
pp. 1273-1293 ◽  
Author(s):  
J. T. Zhang ◽  
H. Lin ◽  
J. P. Sun ◽  
X. J. Feng ◽  
K. A. Gillis ◽  
...  
Keyword(s):  
Acoustic Resonator ◽  
Boltzmann Constant ◽  
Cylindrical Acoustic Resonator

Metrology for Comparison of Displacements at the Picometer Level

2014 ◽  
Vol 625 ◽  
pp. 79-84 ◽  
Author(s):  
Jack Stone ◽  
Patrick Egan ◽  
Jay Hendircks ◽  
Gregory Strouse ◽  
Douglas Olson ◽  
...  
Keyword(s):  
Refractive Index ◽  
Standard Uncertainty ◽  
Boltzmann Constant ◽  
Dimensional Metrology ◽  
Refractive Index Measurement ◽  
Index Measurement ◽  
Relative Standard ◽  
Redefinition Of Si Units ◽  
Optical Analog ◽  
Gas Thermometry

An apparatus capable of comparing displacements with picometer accuracy is currently being designed at NIST. In principle, we wish to compare one displacement in vacuum to a second, equal displacement in gas, in order to determine gas refractive index. If the gas is helium, the refractive index is expected to be amenable to high-accuracy ab initio calculations relating refractive index to gas density or to the ratio of pressure and temperature (P/T); the measured refractive index can then be used to infer (P/T) with an accuracy goal of about 1×10-6(relative standard uncertainty). If either the pressure or temperature is known, the refractive index measurement will allow us to determine the second quantity. Our goal is to achieve an uncertainty limited primarily by the uncertainty of the Boltzmann constant (before redefinition of SI units, which will give the Boltzmann constant a defined value). The technique is an optical analog of dielectric constant gas thermometry and can be used in a similar manner. The dimensional metrology is uniquely challenging, requiring picometer-level uncertainty in the comparison of the displacements.

scholarly journals Determination of the Boltzmann Constant by Laser Spectroscopy as a Basis for Future Measurements of the Thermodynamic Temperature

2010 ◽  
Vol 31 (7) ◽  
pp. 1347-1359 ◽  
Author(s):  
C. Lemarchand ◽  
K. Djerroud ◽  
B. Darquié ◽  
O. Lopez ◽  
A. Amy-Klein ◽  
...  
Keyword(s):  
Laser Spectroscopy ◽  
Thermodynamic Temperature ◽  
Boltzmann Constant

scholarly journals Single Laboratory Validation of a Method for the Determination of Hydroxymethylfurfural in Honey by Using Solid-Phase Extraction Cleanup and Liquid Chromatography

2005 ◽  
Vol 88 (1) ◽  
pp. 121-127 ◽  
Author(s):  
Malcolm Driffield ◽  
Danny Chan ◽  
Roy Macarthur ◽  
Susan MacDonald ◽  
Paul Brereton ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Standard Uncertainty ◽  
Phase Extraction ◽  
Temperature Changes ◽  
Absorbance Detection ◽  
Relative Standard ◽  
Array Detection

Abstract A method is described for the determination of hydroxymethylfurfural (HMF) in honey. The method, which is based on solid-phase extraction cleanup followed by liquid chromatography (LC) with UV absorbance detection, was tested on a variety of different honey types: liquid, set, blended, filtered, crystalline, and comb honey. A sample of honey fortified with a known amount of HMF acted as an in-house reference material. LC with diode-array detection showed that the HMF peak did not contain any peaks of coeluting interfering species. Stability studies showed that honey samples should not be repeatedly frozen and thawed because the temperature changes caused a gradual increase in the HMF concentration. It was also shown that aqueous HMF standard solutions should be kept in the dark at 4°C to avoid degradation of the HMF. The method was internally validated, and the measurement uncertainty was estimated to be ±9.0 at 40 mg/kg, the legal limit. A comparison of the relative standard uncertainty with the Horwitz relative standard deviation showed that the method was suitable for its purpose and should be validated by a collaborative trial.

A radiometric determination of the Stefan-Boltzmann constant and thermodynamic temperatures between -40 °C and +100 °C

1985 ◽  
Vol 316 (1536) ◽  
pp. 85-189 ◽  
Keyword(s):  
Thermodynamic Temperature ◽  
Black Body ◽  
Fourth Power ◽  
Platinum Resistance ◽  
Boltzmann Constant ◽  
A Value ◽  
Standard Deviations ◽  
Radiometric Determination ◽  
Gas Thermometry

The total radiant exitance of a black body at the temperature of the triple point of water, T tp (273.16 K), and at a series of other temperatures in the range from about 233 K ( — 40 °C) to 373 K (100 °C), has been measured by using a cryogenic radiometer. From the measurements at T tp a value for the Stefan—Boltzmann constant or has been calculated: ( r = (5.66967 + 0.00076) x 10 -8 W m -2 K -4 . This is the first radiometric determination of or having an uncertainty comparable with that calculated directly from fundamental physical constants. This measured value differs from the calculated one by 13 parts in 10 5 , which is less than the combined standard deviations of the measured and calculated values. mbined standard deviations of the measured and calculated values. From the measurements of exitance at the other temperatures, values of the corresponding thermodynamic temperature T have been calculated by using Stefan’s fourth-power law. Since the temperature of the radiating black body was also measured by platinum resistance thermometers calibrated on IPTS-68, values of ( T — T 68 ) were obtained. These range from about — (5 + 1.6) mK at 20 °C to — (28 ±2.5) mK at 100 °C and + (5 + 1.5) mK at —40 °C. The results confirm to within a few millikelvins the departure of T 68 from T above 0 °C already discovered by gas thermometry and show that similar departures, but of opposite sign, exist down to the lowest temperature measured, — 40 °C. The uncertainties associated with these new values of T and ( T — T 68 ) are similar to those of the best gas thermometry.

scholarly journals Estimation of the Measurement Uncertainty of the High-Performance Anion-Exchange Chromatographic Determination of Carbohydrates in Soluble (Instant) Coffee

2004 ◽  
Vol 87 (3) ◽  
pp. 647-656 ◽  
Author(s):  
Paul Stöber ◽  
Véronique Giller ◽  
Lionel Spack ◽  
Jacques Prodolliet
Keyword(s):  
Measurement Uncertainty ◽  
Anion Exchange ◽  
High Performance ◽  
Standard Uncertainty ◽  
Calibration Model ◽  
Linear Calibration ◽  
Total Uncertainty ◽  
Instant Coffee ◽  
Relative Standard

Abstract The measurement uncertainty of the determination of free and total carbohydrates in soluble (instant) coffee using high-performance anion exchange chromatography with pulsed amperometric detection according to AOAC Method 995.13 and ISO standard 11292 was calculated. This method is important with regard to monitoring several carbohydrate concentrations and is used to assess the authenticity of soluble coffee. We followed the recommendations of the ISO, Eurachem, and Valid Analytical Measurement (VAM) guides: individual uncertainty contributions u(x) were identified, quantified, and expressed as relative standard deviations related to each specific source u(x)/x or RSD(x). Eventually, they were combined to yield the standard uncertainty and the relative standard uncertainty of a given carbohydrate concentration, c, that is respectively u(c) and u(c)/c. As a result of our study, we could demonstrate that the overall repeatability of the carbohydrate determination in duplicate, RSD(r); the repeatability of the integration of the peak area of the carbohydrate standards, RSD(rarea(ST)); and the uncertainty of the linear calibration model used in our laboratory, RSD (linST), are the most significant contributions to the total uncertainty. The u(c)/c values thus determined differ for each carbohydrate and depend on their concentrations. The least standard uncertainties that can be achieved are about 2.5%. The question of trueness in the total carbohydrate assay (determination of monosaccharides obtained upon hydrolysis of coffee oligo- and polysaccharides) was addressed. For this purpose, we analyzed the data of 2 different collaborative trials in which our laboratory took part.

Acoustic Resonator Experiments at the Triple Point of Water: First Results for the Boltzmann Constant and Remaining Challenges

2010 ◽  
Vol 31 (7) ◽  
pp. 1310-1346 ◽  
Author(s):  
Gavin Sutton ◽  
Robin Underwood ◽  
Laurent Pitre ◽  
Michael de Podesta ◽  
Staf Valkiers
Keyword(s):  
Triple Point ◽  
Acoustic Resonator ◽  
Boltzmann Constant ◽  
Triple Point Of Water ◽  
First Results

scholarly journals Method validation for the determination of fraction of modern (F14C) in wood samples using conventional method

2018 ◽  
Vol 45 (1) ◽  
pp. 68-73
Author(s):  
Rana Baydoun ◽  
Omar El Samad ◽  
Bilal Nsouli ◽  
Ghassan Younes
Keyword(s):  
Method Validation ◽  
Conventional Method ◽  
Limit Of Detection ◽  
Atomic Energy Commission ◽  
Standard Uncertainty ◽  
Technical Requirement ◽  
Internal Validation ◽  
Iso 17025 ◽  
Relative Standard

Abstract The radiocarbon laboratory at the Lebanese Atomic Energy Commission is undertaking environmental studies, in order to determine the anthropogenic impact of technologies on the ecosystem through the determination of radiocarbon content in tree leaves and plants. Thus, it was important to validate the method used to demonstrate that the applied procedure gives reliable results. Method validation is universally applied in analytical laboratories as an essential part of quality assurance system and as a basic technical requirement of the ISO 17025 standard. The conventional method used for determination of Fraction Modern (F14C) is a standard method issued by the American Society for Testing and Materials in 2011 with a code ASTM-D 6866-11 Method C. According to Eurachem guide, internal validation was expressed in terms of accuracy that was evaluated by trueness and precision. Trueness was expressed in terms of relative bias, while for precision ten consecutive replicates were carried out to under repeatability conditions and five duplicates were analyzed under reproducibility conditions. The limit of detection and the minimum detectable activity (MDA) were calculated. Uncertainty sources were defined and their relative standard uncertainties were calculated in order to determine the combined standard uncertainty. Five reference samples of different matrices were analyzed; calculated z score values were acceptable as being between –2 and +2. The calculation and results are presented in this work.

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