Estimation of uncertainty of trypsin inhibitor activity measurement in legume crops

Irradiation of legume seeds has emerged as an attractive alternative compared to conventional chemical treatments in seed production. Irradiation is also used for the decontamination of food and feed in order to increase the shelf-life of fresh and dry food materials. The effects of irradiation on nutritive and anti-nutritive factors such as trypsin inhibitors are usually reported together with the measurements obtained by using the quantitative analytical methods. The objective of this study was to measure trypsin inhibitor activity (TIA) of common bean cultivar Oplenac using the microtiter plate method and to identify factors that contribute to the uncertainty of TIA measurement according to the current Guide to the Expression of uncertainty in measurement (GUM). Dominant sources of uncertainty of TIA measurement were: absorbance measurements of sample and positive control reaction mixtures and preparation of the final sample solution using a graduated cylinder (V4). Absorbance measurement of sample reaction mixtures took 37.8% of the overall measurement uncertainty. Preparation of the final sample solution using a graduated cylinder (V4) and absorbance measurement of positive control reaction mixture contributed to the overall uncertainty with 35.1% and 15.8%, respectively. Acquired insight into factors that contribute to the uncertainty of TIA measurement gives directions for the improvement of TIA testing methods and TIA results management

How To Measure Oscillator’s Short-Term Stability Using Frequency Counter

In this paper a few methods of how to use frequency counter in time-domain frequency stability analysis are described. Three implemented methods are presented. As an experiment, a comparison of the realized methods in the Technical Test Center (TOC) and the “references” obtained in the Directorate of Measures and Precious Metals (DMDM) in Belgrade are accomplished. The measurement uncertainty estimation for time interval measurement with one frequency counter is presented as well

Measurement over an interval method in measuring and monitoring of power quality

Measuring and monitoring of power quality of supplied electric energy are important links in electro-distribution chain. Modern systems used for this purpose are complex. Goal of this paper is to present a new approach to the measurements of power quality, which can achieve equal or better performances using less complicated hardware. In this paper, we have presented the method of measuring over an interval in measurements of relevant factors of power quality: grid voltage frequency, grid voltage RMS and grid voltage distortion factor. Also given is the analysis of performances from metrology point of view, which shows that the measurement uncertainty of proposed method is many times lower than required, regarding maximum deviations from nominal values, defined by the European norm EN50160.[Projekat Ministarstva nauke Republike Srbije, br. TR32019: Measurement in concept of smart grid

Influence of Signal Stationarity on Digital Stochastic Measurement Implementation

The paper presents the influence of signal stationarity on digital stochastic measurement method implementation. The implementation method is based on stochastic voltage generators, analog adders, low resolution A/D converter, and multipliers and accumulators implemented by Field-Programmable Gate Array (FPGA). The characteristic of first implementations of digital stochastic measurement was the measurement of stationary signal harmonics over the constant measurement period. Later, digital stochastic measurement was extended and used also when it was necessary to measure timeseries of non-stationary signal over the variable measurement time. The result of measurement is the set of harmonics, which is, in the case of non-stationary signals, the input for calculating digital values of signal in time domain. A theoretical approach to determine measurement uncertainty is presented and the accuracy trends with varying signal-to-noise ratio (SNR) are analyzed. Noisy brain potentials (spontaneous and nonspontaneous) are selected as an example of real non-stationary signal and its digital stochastic measurement is tested by simulations and experiments. Tests were performed without noise and with adding noise with SNR values of 10dB, 0dB and - 10dB. The results of simulations and experiments are compared versus theory calculations, and comparasion confirms the theory