scholarly journals Reducing the uncertainty of strain gauge amplifier calibration

ACTA IMEKO ◽  
2017 ◽  
Vol 6 (4) ◽  
pp. 69 ◽  
Author(s):  
Miha Hiti
Keyword(s):  
Strain Gauge ◽  
Low Voltage ◽  
Reference Value ◽  
Calibration Method ◽  
Standard Uncertainty ◽  
Relative Standard Uncertainty ◽  
Voltage Ratio ◽  
Relative Standard ◽  
Lower Uncertainty

<p class="Abstract">The article presents a method for calibration of strain gauge bridge amplifiers with improved uncertainty in low voltage ratio range. The procedure is based on combining traditional calibration of the amplifier at one point and linearity determination of the rest of the range. Traditional calibration is performed by a calibrated strain gauge bridge simulator at a reference value where measurement uncertainty is adequate, and the linearity is determined by a combinatorial calibration method with lower uncertainty, employing a special resistance circuit. Uncertainty in the lower part of the amplifier range can be significantly improved, resulting in a combined relative standard uncertainty below 2.5x10<sup>-5</sup> for the range from 0.04 mV/V to 2.5 mV/V.</p>

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.

Headspace Gas Chromatographic Estimation of Some Yogurt Volatiles

1991 ◽  
Vol 74 (4) ◽  
pp. 630-634 ◽  
Author(s):  
Franz Ulberth
Keyword(s):  
Accurate Determination ◽  
Standard Addition ◽  
Calibration Method ◽  
Relative Standard ◽  
Headspace Gas ◽  
Standard Calibration ◽  
Gas Chromatographic Method ◽  
Aroma Components ◽  
Ppm Level

Abstract A headspace gas chromatographic method Is described for the determination of acetaldehyde, ethanol, acetone, dlacetyl, and 2-butanone In yogurt. Yogurt (2 g) is equilibrated 1 h in a 10 mL vial at 60 °C, and 0.25 mL headspace gas Is splitinjected. The volatiles are baseline-separated In less than 5 min by using a thick film capillary column coated with SE-54. An external standard calibration method fulfills the requirements for an accurate determination of the yogurt aroma components. The accuracy of this method was checked by the standard addition method. The precision of the method, In terms of the relative standard deviation, depends on the analyte concentration. At the 10 ppm volatile level, RSD Is 2%, and at the 0.1 ppm level, 15%.

Evaluation of Uncertainty in the Determination of Pesticide Residues in Tea using GC-ECD

2017 ◽  
Vol 19 (1) ◽  
pp. 18-24
Author(s):  
Yohanes Susanto Ridwan ◽  
Andreas Andreas ◽  
Dyah Styarini ◽  
Retno Yusiasih
Keyword(s):  
Pesticide Residues ◽  
Calibration Method ◽  
Standard Uncertainty ◽  
Uncertainty Component ◽  
Method Performance ◽  
Total Uncertainty ◽  
Key Indicator ◽  
Relative Standard ◽  
Calibration Solution ◽  
Pesticides Residue

Key indicator of quality in test results is the uncertainty value, which could be evaluated using several common approach. Uncertainty evaluation in a-endosulfan and bifenthrin in Oolong tea, and cypermethrin in green tea using bottom-up approach showed that uncertainty component arising from GC-ECD instrument calibration, method performance i.e. repeatability and recovery were the main contributors to total uncertainty. Uncertainty component arising from weighing, dilution factor, stock standard solution, calibration solution, and moisture correction had no significant effect to total uncertainty, hence they could be neglected. Relative standard uncertainty obtained for all of pesticides residue were 18.23, 10.44, dan 14.98% for a-endosulfan, bifenthrin, and cypermethrin, respectively. Comparison with 2/3 CV Horwitz of 17.33, 10.62, and 12.44% respectively for all pesticide residues indicated that the evaluation of uncertainties were realistic

Progress toward Système International d'Unités traceable force metrology for nanomechanics

2004 ◽  
Vol 19 (1) ◽  
pp. 366-379 ◽  
Author(s):  
Jon R. Pratt ◽  
Douglas T. Smith ◽  
David B. Newell ◽  
John A. Kramar ◽  
Eric Whitenton
Keyword(s):  
Atomic Force Microscope ◽  
Electrostatic Force ◽  
Standard Uncertainty ◽  
National Standards ◽  
Force Balance ◽  
Traceability Chain ◽  
Relative Standard Uncertainty ◽  
Force Sensitivity ◽  
Atomic Force ◽  
Relative Standard

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/μN. This result suggests that a force derived from measurements of length, capacitance, and voltage provides a viable small force standard consistent with the Système International d’Unités. In this paper, we have measured the force sensitivity of a piezoresistive microcantilever by directly probing the NIST EFB. These measurements were linear and repeatable at a relative standard uncertainty of 0.8%. We then used the calibrated cantilever as a secondary force standard to transfer the unit of force to an optical lever–based sensor mounted in an atomic force microscope. This experiment was perhaps the first ever force calibration of an atomic force microscope to preserve an unbroken traceability chain to appropriate national standards. We estimate the relative standard uncertainty of the force sensitivity at 5%, but caution that a simple model of the contact mechanics suggests errors may arise due to friction.

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 Application of Partial Least-Squares Calibration to Phosphorimetric Data for Determination of Polycyclic Aromatic Hydrocarbons in Spiked Environmental Samples

2000 ◽  
Vol 83 (2) ◽  
pp. 391-398
Author(s):  
A Segura Carretero ◽  
M Martinez Galera ◽  
C Cruces Blanco ◽  
M D Gil García ◽  
A Fernández Gutiérrez ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Least Squares ◽  
Partial Least Squares ◽  
Aromatic Hydrocarbons ◽  
Road Dust ◽  
Calibration Method ◽  
Ternary Mixtures ◽  
Relative Standard ◽  
Polycyclic Aromatic

Abstract A partial least-squares calibration method is proposed, for the first time, for phosphorescence signals. The proposed method is based on the determination of phenanthrene, fluoranthene, and benz[a]anthracene by room temperature phosphorimetry, using microemulsion solutions. The emission and first-derivative emission spectra of the ternary mixtures were tested to perform the calibration matrix. Improved recoveries were found for the prior differentiation step in the analysis of ternary mixtures of these polycyclic aromatic hydrocarbons in road dust samples. The proposed method yielded recoveries ranging from 93.2 to 115.3%, with relative standard deviations of &lt; 6.8%.

scholarly journals Simultaneous Spectrophotometric Determination of Amitriptyline Hydrochloride and Chlordiazepoxide in Pharmaceutical Tablets by Multivariate Calibration Method

2009 ◽  
Vol 6 (s1) ◽  
pp. S111-S116 ◽  
Author(s):  
Amir H. M. Sarrafi ◽  
Ziba Khodakarami ◽  
Masoumeh Karkeabadi
Keyword(s):  
Multivariate Calibration ◽  
Calibration Method ◽  
Test Sample ◽  
Pharmaceutical Products ◽  
Partial Least Square ◽  
Least Square ◽  
Partial Least Square Regression ◽  
Relative Standard ◽  
Amitriptyline Hydrochloride

The multivariate calibration method, partial least square regression (PLS) was applied for the simultaneous spectrophotometry determination of amitriptyline hydrochloride (AMT) and chlordiazepoxide (CHL) in their mixtures. The parameters of chemometric technique were optimized and the proposed method was validated with synthetic samples and applied to analyze these drugs in pharmaceutical products with good accuracy and precision. The results were compared with those given by United State Pharmacopoeia method. The square of the correlation coefficients (R2) for predicted AMT and CHL with the proposed method in a test sample were 0.9951 and 0.9897 respectively. The relative standard deviation for commercial tablets in the proposed method and USP standard method were 0.42 and 2.61%, respectively.

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.

scholarly journals The New 1 kN·m Torque Standard Machine in National Institute of Metrology, China

2021 ◽  
Vol 2095 (1) ◽  
pp. 012072
Author(s):  
Jile Jiang ◽  
Kun Wu ◽  
Bin Guo ◽  
Shi Wu ◽  
Zhimin Zhang
Keyword(s):  
Ambient Temperature ◽  
Radial Direction ◽  
Standard Uncertainty ◽  
Aerostatic Bearing ◽  
Horizontal Alignment ◽  
Relative Standard Uncertainty ◽  
Lever Arm ◽  
Precise Adjustment ◽  
Relative Standard ◽  
Minimum Deformation

Abstract A 1 kN-m deadweight torque standard machine is established in National Institute of Metrology, China. The torque range is 5N·m-1200 N·m. The deadweights utilized in the machine can generate the torque of 1200 N·m, 600N·m, 360N·m, 240N·m, 120N·m and 60 N·m, respectively. The torque can be applied both in clock-wise and counter clock-wise direction in sequencial loading process. The aerostatic bearing is introduced to the torque standard machine in order to eliminate the influence of friction. The symmetric V type rotor and stator are used to provide the reliable support both in axial and radial direction. The material of the lever arm is invar alloy, performing with the minimum deformation with the change of the ambient temperature. The counter torque part will make the precise adjustment to make a horizontal alignment of the lever arm. The relative standard uncertainty of the torque generated by the machine is less than 1e-5.

scholarly journals Development of 1.6 GPa pressure-measuring multipliers

ACTA IMEKO ◽  
2014 ◽  
Vol 3 (2) ◽  
pp. 54 ◽  
Author(s):  
Wladimir Sabuga ◽  
Rob Haines
Keyword(s):  
Finite Element Analysis ◽  
Reasonable Agreement ◽  
Standard Uncertainty ◽  
Feasibility Analysis ◽  
Element Analysis ◽  
Relative Standard Uncertainty ◽  
Pressure Calibration ◽  
Relative Standard ◽  
New Development ◽  
Theoretical Results

Two 1.6 GPa pressure-measuring multipliers were developed and built. Feasibility analysis of their operation up to 1.6 GPa, parameter optimisation and prediction of their behaviour were performed using Finite Element Analysis (FEA). Their performance and metrological properties were determined experimentally at pressures up to 500 MPa. The experimental and theoretical results are in reasonable agreement. With the results obtained so far, the relative standard uncertainty of the pressure measurement up to 1.6 GPa is expected to be not greater than 2·10<sup>-4</sup>. With this new development the range of the pressure calibration service in Europe can be extended up to 1.5 GPa.

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