scholarly journals Experimental quantification of measurement uncertainty and other verification criteria for analytical test methods

2021 ◽  
Vol 2094 (5) ◽  
pp. 052031
Author(s):  
A K Miraliyeva ◽  
A S Rashidov ◽  
Z X Ernazarova ◽  
Sh M Masharipov ◽  
G M Mirpayziyeva

Abstract If the measurement produces a numerical result (or the stated result is based on a numerical result), then it is necessary to evaluate the uncertainty of these numerical results. If the test methodology does not provide for a rigorous, metrologically and statistically reliable estimate of measurement uncertainty, the test laboratory should attempt to reasonably assess the uncertainty of the measurement results. This is applicable in the case of test methods both rational and empirical. As well as in the laboratory activities, verification of test methods plays an important role in order to guarantee the competence of the laboratory by checking for the criteria of Kohren, Grabbs and others. In cases where test results are not numerically expressed or based on numerical data (e.g., fit/unsuitable or positive/negative, or based on visual or sensory perceptions or other forms of quality analysis), estimates of uncertainty or other variability of results are not required. Nevertheless, laboratories are advised to have an idea of the variability of the results, if possible. The importance of the uncertainty of qualitative test results is undeniable, as is the fact that the necessary statistical methodology (procedure) exists for the calculations. However, due to the complexity of the issue and the inconsistency in the approaches, it is not currently necessary for laboratories to assess the uncertainty of qualitative test results. However, this issue needs to be considered. The article discusses estimates of uncertainty of analytical measurements taking into account the requirements of regulatory documents. The criteria for verification of measurement methodology based on experimental works are also considered and analyzed.

2020 ◽  
pp. 53-61
Author(s):  
Nada Nabila Sari ◽  
S Suharyanto

Biji nangka kurang diminati oleh masyarakat sebagai bahan pangan. Biji nangka memiliki kandungan senyawa flavonoid yang dapat digunakan sebagai pengobatan. Tujuan peneliti adalah untuk mengetahui pengaruh lama fermentasi terhadap kadar flavonoid total pada ekstrak tape biji nangka (Artocarpus heterophylla Lamk.) yang dilakukan dengan alat spektrofotometer UV-Vis. Manfaat dari penelitian untuk menambah wawasan di bidang farmasi khususnya tentang ilmu kimia amami mengenai pengaruh lama fermentasi terhadap kadar flavonoid total pada ekstrak tape biji nangka (Artocarpus heterophylla Lamk.). Metode ekstraksi yang digunakan adalah metode maserasi dengan mengunakan pelarut etanol 96%. Identifikasi kualitatif mengunakan uji Shinoda, uji NaOH 10%, uji H2SO4 (pekat). Hasil uji kualitatif menunjukan sampel positif mengandung flavonoid. Kesimpulan pada hasil penelitian penetapan kadar flavonoid total yang terkandung dalam ekstrak tape biji nangka pada hari ke-0 sebesar 2,9146±0,0245 mgQE/gram ekstrak, pada hari ke-1 sebesar 3,3050±0,0240 mgQE/gram ekstrak, pada hari ke-2 sebesar 3,6829±0,0244 mgQE/gram ekstrak, dan pada hari ke-3 sebesar 4,0488±0,0244 mgQE/gram ekstrak.  Jackfruit seeds are less interest by the community (people) as food.  Jackfruit seeds containing flavonoid compounds where it can be used as a treatment.  The aim of the researchers was to determine the effect of fermentation time on total flavonoid concentration  in jackfruit fermented seed extracts with a UV-Vis spectrophotometer. The benefits of research to add insight in the field of pharmacy especially about chemistry of amami regarding effect of fermentation time on total flavonoid levels in jackfruit seed “tape” extract (Artocarpus heterophylla Lamk.). Extraction method used is the maceration method using 96% ethanol solvent. Qualitative identification using the Shinoda test, 10% NaOH test, and H2SO4 (concentrated) test. Qualitative test results showed a positive sample containing flavonoids. Conclusions on the results of the experiment  are jackfruit seed "tape" extract on day-0 was 2.9146±0.0245  mgQE/gram extract, on day-1 was 3.3050±0.0240 mgQE/gram extract, on day-2 was 3.68293±0.0244 mgQE/gram and on day-3 was 4.0488±0.024 mgQE /gram extract. The longer fermentation, total flavonoid concentration interest.  


2019 ◽  
Vol 4 (2) ◽  
pp. 176-183
Author(s):  
Ponco Wali

Testing repeat electronic scales with non-automatic scales technical requirements so far is fairly long if not using a calculator or computer. The aim of this research is to compare the repeatability testing method of electronic scales using methods according to the technical requirements of non-automatic scales and the Australian NMI method, both of which refer to OIML R76 in determining the validity or cancellation of electronic scales repeatability testing. This research method is done through repeat testing on 3 samples of electronic scales, then on each electronic scale 2 test methods are performed. The conclusion is that the electronic scales repeatability testing uses the non-automatic scales technical requirements method and the Australian NMI method has some differences although both refer to OIML R76. These differences include several points, namely the charge used, the method of adding additions, the formula for determining electronic scales, and different test results. The Australian NMI method is deemed to make it easier and more time efficient compared to the non-automatic weighing technical requirements method.


Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 670
Author(s):  
Preeda Chaturabong

Chip seal bleeding is influenced by many factors, including design inputs, material properties, and project-specific conditions. It reduces the surface texture of the pavement and thus compromises the safety of the traveling public. Even though factors that bring about premature bleeding are known, currently, no laboratory test methods for evaluating bleeding in chip seals have been specified. The objective of this paper is to present the results of an investigation of the influence factors of asphalt emulsion residue properties measured by the ASTM D7405 multiple stress creep and recovery (MSCR) test, as well as other factors related to chip seal bleeding resistance as measured by the modified loaded wheel test (MLWT). In this study, the MSCR test was used as a tool for evaluating the performance of asphalt emulsions because it has been identified as a potential test related to bleeding in the field. In addition, MLWT was selected as a tool for evaluating chip seal bleeding performance in the laboratory. The results of the MLWT showed that the emulsion application rate (EAR), aggregate gradation, and emulsion properties were significant factors affecting bleeding. The MSCR test was found to be a promising tool for the performance evaluation of asphalt emulsion residue, as the test was able to differentiate between emulsion chemistries and modifications in terms of sensitivity to both temperature and stress. In relation to chip seal bleeding resistance, only the creep compliance (Jnr) obtained from the MSCR test results was identified as a significant property affecting potential for bleeding.


2013 ◽  
Vol 345 ◽  
pp. 64-67
Author(s):  
Jian Hua Zhao ◽  
Rui Bo Zhang ◽  
De Bin Zhu ◽  
Hong Bin Gao

Shock test of marine diesel engine is the important content for ship anti-shock research. Plentiful shock tests of equipments have been carried out abroad, but there is no detailed test methods of diesel engine. According to simulation results, 8-channel acceleration test points are determined. Because diesel engine is working, the measured shock acceleration is interfered by vibration signal. Orthogonal wavelet decomposition and wavelet noise reduction methods are used to separate shock component from test results. The seperated shock component consists of two parts. One is the low-frequency part caused by the shock from diesel foundation and then attenuation through the isolator, the other is the high-frequency part caused by the secondary shock of the retainer.


2015 ◽  
Vol 830-831 ◽  
pp. 191-194
Author(s):  
M. Venkateswara Rao

Conventional tensile test methods are used for service exposed high temperature boiler tubes to evaluate the deterioration in mechanical properties such as tensile strength, yield strength and percentage elongation. The mechanical properties are required to be evaluated periodically as the boiler components undergo material degradation due to aging phenomena. The aging phenomena occurs due to continuous exposure of tubes to high temperature & pressure steam prevailing inside the tubes and high temperature exposure to corrosive combustible gases from the external surfaces within the boiler.A recent developed new technique called small punch testing has been used to evaluate the tensile properties of SA 213T22 grade steel predominantly exists in super-heater and re-heater sections of boiler. The small punch tests have been carried out on the miniature disk shaped specimens of diameter of 8.0 mm and 0.5 mm thickness extracted from both the new and service exposed tubes. Conventional uniaxial tensile tests on standard specimens from the same tube material have also been performed for comparison. The service exposed tubes showed considerable loss in mechanical properties in both the conventional and small punch test results. Correlations of tensile properties have been obtained based on the comparative analysis of both small punch and uniaxial tensile test results. Further, the study showed that an appropriate empirical relation could be generated for new and service exposed materials between both the techniques. Conventional test methods require large quantity of material removal for test samples from in-service components whereas small punch test method needs only a miniature sample extraction. This small punch test technique could also be extended to evaluate the thicker section boiler components such as pipelines and headers in the boiler as a part of remaining life assessment study. Also this technique could be a useful tool to any metallic component where large quantity of sample removal may be difficult or may not be feasible.


1995 ◽  
Vol 13 (2) ◽  
pp. 127-140 ◽  
Author(s):  
Richard Jupe ◽  
Donald K. Shipley ◽  
William Z. Hudson ◽  
Joseph T. Wanna ◽  
Linda C. Greear

Two bolts of cotton duck fabric that meet military specifications and the purchasing guidelines described by the National Institute of Standards and Technology (NIST) for use as a substrate in "Test Methods for Quantifying the Propensity of Cigarettes to Ignite Soft Furnishings" were tested with smoldering cigarettes to determine the effect of inter-bolt variations on cigarette ignition propensity test outcome. The test was designed around an ASTM method that calls for the control of all known test variables, except for those inherent to the fabric's manufacture. The ignitability of each fabric was determined by testing two sets of 48 replications for each of two experimental cigarettes. The two bolts of cotton duck fabric showed a statistically significant difference in ignitions, independent of environmental and experimental fac tors. Two additional bolts of cotton duck #4 were analyzed. Cigarette ignition test results and the physical parameters of the additional bolts offer evidence that the NIST specifications are difficult to meet and further that test results are extremely sensitive to fabric properties.


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