scholarly journals CONFORMITY ASSESSMENT OF TEMPERATURE MEASURING DEVICES USED IN FORENSIC SCIENCE LABORATORIES UNDER ISO/IEC 17025: 2017

2021 ◽  
Vol 9 (06) ◽  
pp. 42-50
Author(s):  
Emel Hulya Yukseloglu ◽  
◽  
Hakan Arpacik ◽  
FatmaCavus Yonar ◽  
Dilek Salkim Islek ◽  
...  
Keyword(s):  
Measurement Uncertainty ◽  
Forensic Science ◽  
Calibration Method ◽  
Conformity Assessment ◽  
Quality Management Systems ◽  
Digital Thermometer ◽  
Measuring Devices ◽  
Measurement Results ◽  
Science Laboratories ◽  
Uncertainty Parameters

Calibration is an expectation for quality management systems as well as a need for laboratories. If there is a need to measure the size in the laboratory, there is also a need to determine whether the measuring instrument used there is measuring with the desired accuracy.In our study, the suitability of the digital thermometer, which is one of the devices used in the forensic science laboratory during the examination of the evidence, was examined within the scope of ISO / IEC 17025: 2017 standard.The temperature of the environment is very important during the analysis of the evidence.Therefore, it is important to determine the measurement uncertainty and confidence interval in the thermometer that measures this temperature.For this reason, in our study, the calibration procedures were carried out by selecting the digital thermometer device and using the calibration method compared to the reference.Uncertainty budgets were prepared by calculating the measurement uncertainty parameters one by one. Conformity assessment was made according to the measurement results.

scholarly journals IUPAC/CITAC Guide: Evaluation of risks of false decisions in conformity assessment of a multicomponent material or object due to measurement uncertainty (IUPAC Technical Report)

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ilya Kuselman ◽  
Francesca R. Pennecchi ◽  
Ricardo J. N. B. da Silva ◽  
David Brynn Hibbert
Keyword(s):  
Measurement Uncertainty ◽  
Joint Probability ◽  
Ambient Air ◽  
Conformity Assessment ◽  
Total Probability ◽  
Global Risk ◽  
Total Risk ◽  
Multivariate Distributions ◽  
Measurement Results ◽  
Multicomponent Material

AbstractRisks of a false decision on conformity of the chemical composition of a multicomponent material or object due to measurement uncertainty are defined using the Bayesian approach. Even if the conformity assessment for each particular component of a material is successful, the total probability of a false decision (total consumer’s risk or producer’s risk) concerning the material as a whole might still be significant. This is related to the specific batch, lot, sample, environmental compartment, or other item of material or object (specific consumer’s and producer’s risks), or to a population of these items (global consumer’s and producer’s risks). A model of the total probability of such false decisions for cases of independent actual (‘true’) concentrations or contents of the components and the corresponding measurement results is formulated based on the law of total probability. It is shown that the total risk can be evaluated as a combination of the particular risks in the conformity assessment of components of the item. For a more complicated task, i.e. for a larger number of components under control, the total risk is greater. When the actual values of the components’ concentrations or contents, as well as the measurement results, are correlated, they are modelled by multivariate distributions. Then, a total global risk of a false decision on the material conformity is evaluated by the calculation of integrals of corresponding joint probability density function. A total specific risk can be evaluated as the joint posterior cumulative function of actual property values of a specific item lying outside the multivariate specification (tolerance) domain when the vector of measured values obtained for the item is inside this domain. The effect of correlation on the risk is not easily predictable. Examples of the evaluation of risks are provided for conformity assessment of denatured alcohols, total suspended particulate matter in ambient air, a cold/flu medication, and a PtRh alloy.

The accuracy and precision of interface pressure measuring devices: A systematic review

2021 ◽  
pp. 026835552110080
Author(s):  
Orsolya Kokai ◽  
Sharon L Kilbreath ◽  
Patrick McLaughlin ◽  
Elizabeth S Dylke
Keyword(s):  
Systematic Review ◽  
Applied Pressure ◽  
Calibration Method ◽  
Interface Pressure ◽  
Measuring Devices ◽  
Pressure Application ◽  
Accuracy And Precision ◽  
Major Factors ◽  
No Sensor

Introduction Interface pressure measuring devices are used to assess the pressures exerted by compression. Their performance, however, has not been considered as a contributing factor to reported inconsistences in the application of compression. A systematic review was undertaken to investigate the performance of commercially available devices used to measure interface pressure. Methods Six databases were searched identifying 17 devices, grouped into five sensor categories. Results A range of methodologies assessed the devices’ accuracy and precision, including method of pressure application, device calibration and type of surface used. No sensor category outperformed the others, however some individual sensors showed higher accuracy and/or precision compared to others. Two major factors influenced the performance of a number of sensors: the amount of applied pressure and the calibration method used. Conclusion Inconsistences in the application of compression may reflect, in part, issues related to accuracy and precision of the devices used to assess compression.

Estimation of uncertainty in olfactometry

2009 ◽  
Vol 59 (7) ◽  
pp. 1409-1413 ◽  
Author(s):  
T. Higuchi
Keyword(s):  
Measurement Uncertainty ◽  
Interlaboratory Comparison ◽  
Collaborative Study ◽  
Estimation Procedure ◽  
Measurement Model ◽  
Standard Uncertainty ◽  
Expanded Uncertainty ◽  
Collaborative Test ◽  
Measurement Results ◽  
Estimation Of Uncertainty

Estimation of uncertainty in odour measurement is essential to the interpretation of the measurement results. The fundamental procedure for the estimation of measurement uncertainty comprises the specification of the measurement process, expression of the measurement model and all influences, evaluation of the standard uncertainty of each component, calculation of the combined standard uncertainty, determination of a coverage factor, calculation of the expanded uncertainty and reporting. Collaborative study such as interlaboratory comparison of olfactometry yields performance indicators of the measurement method including repeatability and reproducibility. Therefore, the use of collaborative test results for measurement uncertainty estimation according to ISO/TS 21748 and ISO 20988 is effective and reasonable. Measurement uncertainty of the triangular odour bag method was estimated using interlaboratory comparison data from 2003 to 2007 on the basis of the simplest model of statistical analysis, and the expanded uncertainty of odour index ranged between 3.1 and 6.7. On the basis of the establishment of the estimation procedure for uncertainty, a coherent interpretation method for the measurement results will be proposed and more effective and practical quality control of olfactometry will be available.

Practice of offender profiling in Japan

2017 ◽  
Vol 19 (3) ◽  
pp. 187-194 ◽  
Author(s):  
Kaeko Yokota ◽  
Hiroki Kuraishi ◽  
Taeko Wachi ◽  
Yusuke Otsuka ◽  
Kazuki Hirama ◽  
...  
Keyword(s):  
Forensic Science ◽  
National Survey ◽  
Prediction Accuracy ◽  
Current Situation ◽  
Demographic Characteristics ◽  
Statistical Analyses ◽  
Offender Profiling ◽  
Police Investigations ◽  
Science Laboratories ◽  
Crime Linkage

The main aim of this study was to determine the current situation of offender profiling in Japan. In addition, the accuracy of crime linkage and inferring offenders’ profiles were examined. To evaluate offender profiling comprehensively, we conducted a national survey of 156 people responsible for offender profiling between 2011 and 2012 to obtain their demographic characteristics and experience related to profiling. Furthermore, we also used a sample of 296 resolved cases to examine the content of profiling and the accuracy of predictions in offender profiling. The results of the statistical analyses revealed that police professionals from various backgrounds were engaged in profiling in Japan; 76% were police investigators, and 19% were professionals at forensic science laboratories engaged in psychological work. Regarding the utilization of profiling results in police investigations, 46% of profiling ‘led to identification of offender’. As for prediction accuracy, the rate of linkage errors (i.e. where profilers could not correctly link incidents even when they knew of the occurrence of these incidents) was 15%. Accurately inferring an offender’s profile was found to be between 72% (means of transportation) and 100% (sex). We also discussed the challenges faced by the police who practise offender profiling in Japan.

Medical Technologists in Forensic Science Laboratories in the United States

1991 ◽  
Vol 22 (1) ◽  
pp. 40-44
Author(s):  
Richard O. Pfau ◽  
John R. Snyder ◽  
Sally V. Rudmann ◽  
Joseph E. Scott
Keyword(s):  
United States ◽  
Forensic Science ◽  
The United States ◽  
Science Laboratories ◽  
Medical Technologists

scholarly journals Restoration of Obliterated Stamped Marks on Aluminium Surfaces by Metallographic Etching Technique

2020 ◽  
Vol 36 (6) ◽  
pp. 1212-1217
Author(s):  
Amit Kumar ◽  
Ankit Srivastava ◽  
Tanurup Das ◽  
Abhimanyu Harshey ◽  
Veer Raj Saini ◽  
...  
Keyword(s):  
Forensic Science ◽  
Ferric Chloride ◽  
Present Experiment ◽  
Chemical Etching ◽  
Simple Technique ◽  
Distilled Water ◽  
Metallic Surfaces ◽  
Etching Technique ◽  
Restoration Process ◽  
Science Laboratories

Serial number restoration is a frequently encountered problem in forensic science laboratories for the investigation of theft and burglary cases. These identification marks are generally introduced over metallic surfaces of different vehicle parts and firearms by various means. Chemical etching is one of the most effective and simple technique to restore obliterated, erased, over-stamped and over-engraved marks on metallic surfaces. Several significant studies on restoration of engraved markings on aluminium surfaces were previously reported. The present study attempts to find out an efficient and fast etching reagent to restore obliterated stamped marks on aluminium surfaces. Ten effective etching reagents previously reported by various researchers in their restoration studies were assessed in the present experiment. Etching reagents were individually applied on obliterated surfaces by the cotton swabbing method. The Reagent 3 (ferric chloride 25 g, conc. HCl 25 mL, distilled water 100 mL) was found out to be the most sensitive and rapid (4–6 min) for the restoration on aluminium surfaces. The study also revealed that the absence of an alkaline compound in etching reagent potentially accelerates the speed of the restoration process.

Measurement Uncertainty

2007 ◽  
Author(s):  
D. Brynn Hibbert
Keyword(s):  
Measurement Uncertainty ◽  
Uncertainty Budget ◽  
Test Material ◽  
Metrology In Chemistry ◽  
Energy Agency ◽  
Long Run ◽  
Measurement Results ◽  
Trading Partners ◽  
History Of ◽  
Student’S T

One of the great revolutions in metrology in chemistry has been the understanding of the need to quote an appropriate measurement uncertainty with a result. For some time, a standard deviation determined under not particularly well-defined conditions was considered a reasonable adjunct to a measurement result, and multiplying by the appropriate Student’s t value gave the 95% confidence interval. But knowing that in a long run of experiments repeated under identical conditions 95% of the 95% confidence intervals would include the population mean did not answer the fundamental question of how good the result was. This became evident as international trade burgeoned and more and more discrepancies in measurement results and disagreements between trading partners came to light. To determine if two measurements of ostensibly the same measurand on the same material give results that are equivalent, they must be traceable to the same metrological reference and have stated measurement uncertainties. How to achieve that comparability is the subject of this chapter and the next. When making a chemical measurement by taking a certain amount of the test material, working it up in a form that can be analyzed, calibrating the instrument, and performing the measurement, analysts understand that there will be some doubt about the result. Contributions to uncertainty derive from each step in the analysis, and even from the basis on which the analysis is carried out. An uncertainty budget documents the history of the assessment of the measurement uncertainty of a result, and it is the outcome of the process of identifying and quantifying uncertainty. Although the client may only receive the fruits of this process as (value ± expanded uncertainty), accreditation to ISO/IEC 17025 requires the laboratory to document how the uncertainty is estimated. Estimates of plutonium sources highlight the importance of uncertainty. The International Atomic Energy Agency (IAEA) estimates there are about 700 tonnes of plutonium in the world. The uncertainty of measurement of plutonium is of the order of 0.1%, so even if all the plutonium were in one place, when analyzed the uncertainty would be 700 kg (1000 kg = 1 tonne). Seven kilograms of plutonium makes a reasonable bomb.

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