Calculation Of Combined Uncertainty Research Articles

ANALISIS HASIL KALIBRASI ALAT PHOTOTHERAPY MERK GEA MEDICAL TYPE XHZ-90

Babies born prematurely always increase every year. For this reason, it is necessary to take proper care so that the baby remains in good health. One of the treatments for premature babies is phototherapy to reduce bilirubin levels in the baby's body. In order for the phototherapy process to run as expected, of course the phototherapy equipment used in the treatment must be of good quality and quality. For this reason, quality assurance and phototherapy equipment need to be carried out through a calibration process. In this study, calibration of the GEA medical type XHZ-90 phototherapy tool was carried out. Calibration is carried out by following the standard reference work method from the Ministry of Health in 2018. Calibration is carried out by checking the physical and function of the equipment which gains a weight of 10%, electrical safety inspection of the appliance with a weight gain of 36%, and measuring the performance of the instrument, namely spectral irradiance with a weight gain of 50%. . So that the total weight gain can be 96% and it can be concluded that this tool is functioning properly and within the tolerance limits of use. The uncertainty value in the measurement of spectral irradiance takes into account the sources of uncertainty types A and B. The combined uncertainty calculation from several sources for the measurement of spectral irradiance is 1.116. This value has met the uncertainty tolerance limit value of ≥ 4.

Uncertanity of Measurement During Estimation of 23 Organophosphorus Pesticides Residue Present in Bottle Gourd

46The study presents the assessment of uncertainty calculation generated, within the analysis of selected 23 organophosphrus pesticides residues of bottle guard. The samples were prepared by using a modified quick, easy, cheap, effective, rugged and safe (QuEChERS) analytical protocol. Multiresidue method used for analysis of samples consisted of (i) acetonitrile extraction, (ii) PSA/C18 clean-up and (iii) identification/quantification of residues by GC utilizing either (nitrogen–phosphorus) or mass-selective detectors (quadrupole analyzer) were evaluated. Major sources like weighing of standard, purity of certified reference material, precision study i.e repeatability and standard solution preparation for calculation of uncertainty of method, was considered. Identification of uncertainty sources, quantification of uncertainty sources and calculation of combined uncertainty are steps for calculation of uncertainty. All the individual uncertainty calculated are combined, later converted to expanded uncertainty.

Measurement uncertainty evaluation with correlation for dynamic tensile properties of auto-body steel sheets

This paper is concerned with evaluation of the measurement uncertainty of true stress−true strain curves of auto-body steel sheets at various strain rates considering correlation of input quantities. The measurand is defined as the true stress at strain rates ranging from 1 to 100s−1. The true stress has a functional relation with the tensile load, the initial width and the initial thickness, the initial and deformed length of a specimen. Since the initial and deformed lengths of a specimen are measured by the exactly same procedure, the two quantities are correlated and considered in the uncertainty evaluation model. An analytic model to evaluate the measurement uncertainty is established properly by considering the correlation with the guidelines suggested by the GUM, ISO/IEC Guide 98-3. The standard uncertainties of the input quantities and influence factors are evaluated for dynamic tensile properties of DDQ, TRIP980, and TRIP1180 steel sheets as well as the covariance associated with the correlated input quantities. The standard uncertainty of the true stress is also evaluated to consider the change of the strain rate during the test. The combined standard uncertainty is then evaluated including standard uncertainties of the input quantities and influence factors. The expanded uncertainty is obtained by choosing an appropriate coverage factor. The absolute amount of the measurement uncertainty decreases with consideration of the correlation between the initial and deformed length since their uncertainty contributions are almost canceled during the calculation of combined uncertainty. Finally, the reliability of dynamic tensile properties of auto-body steel sheets is presented with a statement of the expanded uncertainty.

Fuzzy set theory based methodology for the analysis of measurement uncertainties in river discharge and stage

The discharge and stage measurements in a river system are characterized by a number of sources of uncertainty, which affects the accuracy of a rating curve established from measurements. This paper presents a fuzzy set theory based methodology for consideration of different sources of uncertainty in the stage and discharge measurements and their aggregation into a combined uncertainty. The uncertainty in individual measurements of stage and discharge is represented using triangular fuzzy numbers, and their spread is determined according to the International Organization for Standardization (ISO) standard 748 guidelines. The extension principle based fuzzy arithmetic is used for the aggregation of various uncertainties into overall stage–discharge measurement uncertainty. In addition, a fuzzified form of ISO 748 formulation is used for the calculation of combined uncertainty and comparison with the fuzzy aggregation method. The methodology developed in this paper is illustrated with a case study of the Thompson River near Spences Bridge in British Columbia, Canada. The results of the case study show that the selection of number of velocity measurement points on a vertical is the largest source of uncertainty in discharge measurement. An increase in the number of velocity measurement points provides the most effective reduction in the overall uncertainty. The next most important source of uncertainty for the case study location is the number of verticals used for velocity measurements. The study also shows that fuzzy set theory provides a suitable methodology for the uncertainty analysis of stage–discharge measurements.

The importance of a correct dead time setting in isotope ratio mass spectrometry: Implementation of an electronically determined dead time to reduce measurement uncertainty

Dead time determinations on a mass spectrometry system with ion counting detection can either be done using an isotope ratio measurement approach or via electronic examination of individual components, e.g., the pulse amplifier. Depending on the dead time of each component in the signal chain, the electronically determined result may not represent the true value for the total system, i.e., there might be a series of hardware related dead times. However, a hardware set artificial dead time in the pulse counting system that is long enough might yield a system dead time that can be represented by this set dead time solely. It is shown in this work that a carefully chosen, artificially introduced set dead time yields a system that may be characterized to a much lower uncertainty than is possible using ratio-based measurement approaches. Ultimately, the impact of the dead time on the combined uncertainty of an isotope abundance ratio measurement may be negligible even at very high count rates, i.e., >1 Mcps. In other words, incorporating the dead time contribution in a combined uncertainty calculation would no longer be necessary.

Uncertainty of species unspecific quantification strategies in hyphenated ICP-MS analysis

Owing to the lack of standards and certified reference materials for a variety of elemental species in specific matrices the application of species unspecific quantification strategies employing ICP-MS detection has gained more and more importance. The comparison of different calibration strategies by assessing their main sources of uncertainty is a prerequisite for accurate results. A flow injection (FI) model experiment, using a constant spike flow provided by a HPLC pump, and the chromatographic separation of three platinum species were conducted for fundamental evaluation of on-line isotope dilution mass spectrometry (IDMS) used for species unspecific quantification. A cisplatin standard solution was injected into a flow supplied by a HPLC pump for the FI study. This flow was mixed with a constant make-up flow containing an isotopically enriched 196Pt standard. A make-up (fsp) flow of 117 mg min−1 was determined gravimetrically. In comparison, a make-up flow calculation based on reverse ID calibration, i.e., injection of a standard solution of natural isotopic composition, was found to produce significantly biased results. Make-up flow values of 174, 148 and 143 mg min−1 were obtained depending on the peak width of the FI signal (0.7, 1.22, 1.39 min, respectively). A full combined uncertainty calculation, accounting for possible sources of uncertainty in the measurement process, was carried out for both methods and compared with an uncertainty budget which was set up for single point external calibration with internal standardization. On-line IDMS based on gravimetric spike mass flow determination showed a total combined uncertainty of 8%. A comparable uncertainty of 9% was calculated for single point external calibration with internal standardization, since with the investigated FI experiment sources of uncertainty such as gradient elution did not need to be considered. The high total combined uncertainty of 17% of the second investigated on-line IDMS procedure is mainly determined by mass-flow determination. Generally, the final combined uncertainty of on-line IDMS quantification was found to critically depend on the number of measured data points s−1 defining the peak. The species unspecific quantification methods were evaluated for HPLC-ICP-MS analysis of cisplatin and two of its hydrolysis products. On-line IDMS based on gravimetrical mass flow determination was an absolute prerequisite for obtaining accurate results in terms of total platinum concentration.

Determination of zinc in plant samples by isotope dilution inductively coupled plasma mass spectrometry

Determination of zinc involved spiking with 68Zn enriched solution, digestion by HNO 3+H 2O 2 in microwave decomposition unit, off-line separation of zinc on Chelex-100 column and measurement of ( 64Zn+ 66Zn)/ 68Zn isotope ratio on ICP-MS spectrometer with a quadrupole mass filter. After optimization of standard operation procedure (details are given) the method was validated. LOD was found to be 0.3 μg g −1 for the procedure without zinc separation and 3.6 μg g −1 for the procedure involving zinc separation, respectively. The accuracy of results was proved by analyses of several CRM and a primary solution of zinc, the concentration of which was verified by gravimetry and complexometric titration. Barium is the only element causing serious interferences and it must be removed from samples. The uncertainty budget is given together with the scheme of combined uncertainty calculation. The main uncertainty components are contamination during zinc separation and uncertainty of isotopic composition of natural zinc.

High resolution ID-ICP-MS certification of an estuary water reference material (LGC 6016) and analysis of matrix induced polyatomic interferences.

Reliable trace metal analysis of environmental samples is dependent upon the availability of high accuracy, matrix reference standards. Here, we present Cd, Cu, Ni, Pb and Zn isotope dilution determination for an estuary water certified reference material (LGC 6016). This work highlights the need for high-accuracy techniques in the development of trace element CRMs rather than conventional inter-laboratory trials. Certification of the estuary water LGC6016 was initially determined from a consensus mean from 14 laboratories but this was found to be unsatisfactory due to the large discrepancies in the reported concentrations. The material was re-analysed using isotope dilution ICP-MS techniques. Pb and Cd were determined using a conventional quadrupole ICP-MS (Elan 5000). Cu, Zn and Ni were determined using a magnetic sector ICP-MS (Finnigan Element), which allowed significant polyatomic interferences to be overcome. Using the magnetic sector instrument, precise mass calibration to within 0.02 amu permitted identification of the interferences. Most interferences derived from the sample matrix. For example, the high Na content causes interferences on 63Cu, due to the formation of 40Ar23Na and 23Na2 16O1H, which in a conventional quadrupole instrument would relate to an erroneous increase in signal intensity by up to 20%. For each analyte a combined uncertainty calculation was performed following the Eurachem/GTAC and ISO guideline. For each element a combined uncertainty of 2-3% was found, which represents a 10-fold improvement compared to certification by inter-laboratory comparison. Analysis of the combined uncertainty budget indicates that the majority of systematic uncertainty derives from the instrumental isotope ratio measurements.