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Anton Petrenko, Serhii Kulyk, Oleksandr Lameko, Volodymyr Melnyk, Liudmyla Ovchar, Oleksandra Manska, Olena Shcherbakova, Oleksandr Melnykov
Metrology for protein content measurement in food

Suggestions for establishing metrological traceability and respect metrological traceability chain scheme for protein content measurements in food are presented. The most common methods for determining protein content in organic and inorganic substances are reviewed. Particular attention is given to the Kjeldahl method. A method is proposed for ensuring metrological traceability of the Kjeldahl method results through the use of 2-amino-2-(hydroxymethyl)-1,3-propanediol (Tris base) and hydrochloric or sulfuric acid solutions, whose concentrations are traceable to a primary method—constant current coulometry. A constant current coulometry measurement system has been developed at the Ukrainian DI UMTS and is described in this paper.

John Kenneth Valerio, Aldrin Jan Tabuso, Anton John Rocha, Alleni Junsay, Kim Christopher Aganda
Method Validation of Total Reflection X-ray Fluorescence (TXRF) Analysis as a Screening Method for Mercury (Hg) in Philippine Milkfish

Mercury (Hg) is a naturally occurring element that is released to bodies of water through anthropogenic activities, industrial discharges, or from the existing Hg in soils. Its presence can cause bioaccumulation in aquatic species, which poses potential health risks when taken for human consumption. The most common method for elemental analysis in fish samples is inductively coupled plasma (ICP) spectroscopy, which is highly accurate but has high cost and analysis time. Recently, X-ray fluorescence (XRF) has gained attention for its heavy metal detection capability, which is cheaper and requires less sample preparation compared to ICP. For this study, analysis of Hg content in milkfish using Total Reflection X-ray Fluorescence (TXRF) spectrometry was validated using Philippine Reference Material (PRM) 2002-As, Cd, Hg & Pb in Milkfish produced by the DOST-ITDI National Metrology Division with a recovery range of 93-104%. The relative standard deviation (RSD) of the collected dataset is less than 10%, and the calculated expanded uncertainty was 0.08 ppm. For confirmation, DORM-5 was analyzed, resulting in 98.885% Hg recovery. Overall, the study showed that the TXRF analysis is a cheaper and reliable alternative method in detecting trace Hg content in milkfish samples; therefore, making it suitable for screening and evaluation of mercury in milkfish samples.

Abegail Santillan, Marianne Therese Bauca, Lynne Jerisa Castro, Zamantha Nadir Martin, Araceli Monsada
Intelligent Data Analysis System (IDAS) tool for Oxidation State Analysis of Copper Leadframes using Auger Electron Microprobe

The Semiconductor and Electronics (S&E) sector is vital to the Philippine economy, with copper (Cu) extensively used in semiconductor packaging. However, Cu’s susceptibility to oxidation can impair leadframe reliability. This study establishes an Auger electron spectroscopy (AES) spectral profiling database to identify oxidation states in Cu alloy-based leadframes, using the Intelligent Data Analysis System (IDAS) developed by DOST-ITDI and ASTI. Oxidation was simulated via controlled heat treatment, with surface changes analyzed through optical microscopy, FE-SEM, EDS, and AES. Optimized AES parameters (10.0 kV, 10.0 nA) were validated using Cu and Cu₂O references. Oxidation resulted in color changes, increased surface texture, and chemical modification, with AES confirming the conversion of Cu to Cu₂O. Principal Component Analysis (PCA) and k-means clustering using IDAS effectively classified oxidation states, with PC1, PC2, and PC3 accounting for 42.22%, 25.06%, and 6.94% of the variation, respectively. This demonstrates IDAS as a reliable tool for monitoring copper degradation in semiconductor packaging.

Lynne Jerisa A. Castro, Jane Cathleen B. Gabunada, Clarisse Jasmine J. Carlos, Charisse M. Mendoza, Angelene J. Alcain, John Paul D. Arcilla, Alec N. Tobias, Kim Christopher C. Aganda, Araceli M. Monsada
Microplastics detection in milkfish (Chanos chanos) from selected aquaculture farm in the Philippines

The reliable detection and analysis of microplastics (MPs) are crucial for the development of solutions to mitigate their potential impacts on the environment and human health. However, the removal of biological materials remains a significant challenge as MPs may be obscured by biological matter, complicating their isolation. This study optimized the digestion and extraction of MPs from milkfish parts using KOH combined with a dual-density separation involving NaCl and NaI solutions. Reference micropolymers were spiked into the fish parts to assess % recovery. Results revealed excellent digestion efficiencies and % recoveries (≈90%) in 10% KOH solution. The method was also applied to milkfish collected from Southeastern Mindanao, Philippines. Cellulose, PE, PP, PA, and PET polymers were detected. The average number of MPs found in the meat, fat, GIT, head, and gills were 1.2 ± 0.6, 2.4 ± 2.6, 0.5 ± 1.0, 2.6 ± 2.1 and 0.3 ± 1.0, respectively.

Kiril Demerdziev, Vladimir Dimchev
Reactive power/energy instruments in harmonically distorted conditions – analysis of different measuring algorithms’ response in relation to fundamental reactive power

The measurement of reactive power/energy in non-sinusoidal conditions presents several challenges. The primary issue is the ambiguous definition of reactive power in the presence of high order harmonics. International standard IEEE 1459 addresses this by emphasizing fundamental power components for system monitoring, even in polluted conditions. Another challenge is the existence of different measuring algorithms, implemented in modern devices, which yield consistent response for sinusoidal waveforms, but differ under harmonically distorted voltages and currents. This study experimentally verifies the readings of various meters for reactive power/energy against mathematically modeled outputs. The reference quantity for analysis is fundamental reactive power, as defined in Std. IEEE 1459. The experiments include both single-harmonic and randomly distorted signals, with error analysis based on the share of fundamental reactive power. To ensure high metrological accuracy, the study employs reference standards of the highest accuracy class, traceable to BIPM intrinsic standards.

Vedran Šimunović, Vilim Kožuh, Gorana Baršić
Possibilities of calibrating the piezo actuator using the laser interferometer in Croatian National Laboratory for Length

Only a few of the most advanced national metrology institutes have a Calibration and Measurement Capabilities calibration service in the BIPM Key Comparison Database to calibrate piezoelectric actuators. Given the importance of precise displacement measurements in various high-precision applications, research on the feasibility of calibrating a piezoelectric actuator using a laser interferometer was conducted at the Croatian National Laboratory for Length. In this research a displacement actuator P–621.ZCD, manufactured by Physik Instrumente, has been calibrated using Renishaw ML10 laser interferometer equipped with an EC10 environmental compensation unit. The calibration was performed within a calibration range of up to 1 μm. The paper provides a detailed description of the measurement procedure, the obtained results, and the evaluation of measurement uncertainty.

Argielou Flores, Kiveen Suycano, Jessie Yap, Jheison Corpus, Willard German, Patrick Karlvin Pimentel, Jomari Madlangbayan, Janelle Caringal
Upgrading Manual Mass Comparator by Developing of an Automated Rotary Plate Multi-Position Weighing System

Calibration of mass standards using manual mass comparators requires the repetitive loading and unloading of masses. The routine heavy-lifting could pose a threat to the integrity of the mass comparator and musculoskeletal health of the personnel. This study developed an automated rotary plate that served as an accessory for existing manual comparators in the laboratory. It is programmed to mimic the calibration process by alternately conveying the reference and test mass standards to and from the comparator. The results showed that the new calibration system can produce repeatability results that is up to 75% better than manufacturer’s declaration and 18% better than manual calibration. This demonstrates that the integration of the system enhances the repeatability of the manual mass comparators. This implies that the system can potentially be used to calibrate mass standards of even higher accuracy class than its intended application in the laboratory.

Bartlomiej Cieszynski, Joao Gregorio
The Impact of Data Quality on ML Diagnostic Models: Ensuring Reliability in Medical AI

The application of artificial intelligence and machine learning algorithms in healthcare has grown exponentially in recent years, offering benefits such as improving diagnostic accuracy, efficiency, and addressing challenges such as interpretative bias or the increasing volume of patient data. However, ensuring the reliability of such models necessitates robust evaluations of their sensitivity to data quality – the extent to which data meets required standards. This study explores how variations in data accuracy, precision, and completeness affect an algorithms’ ability to correctly classify electrocardiogram results. The models analysed, namely K-Nearest Neighbours, Random Forest, Artificial Neural Networks, and Convolutional Neural networks were selected due to their prevalence in electrocardiogram classification tasks. Using the PhysioNet’s MIT-BIH Arrhythmia Dataset, the study classifies five types of beats defined by the AAMI EC57. To simulate varying data quality, the dataset has undergone systematic degradation through the addition of noise, rounding of numerical, and removing data features. The re-evaluation of model performance, quantified by model accuracy, precision, and recall has highlighted the effects of data quality on diagnostic outcomes, providing insights into the robustness of models under suboptimal conditions. By examining these critical factors, the study aims to inform the development of more reliable machine learning diagnostic systems, raising awareness of the importance of data integrity in medical applications. The study has shown that model performance is most sensitive to accuracy, completeness and precision in descending order; with accuracy showing greatest reduction in model predictions. It has also displayed that model sensitivity is correlated with class population, as low represented classes have yielded greater deviation under the application of data degradation.

Pauline Ann Quiton, Aaron Dacuya, Johnester Maniego, Angelo Bryan Lazo, Christian D. Lario, Clarissa J. Gatchalian, Elyson Keith P. Encarnacion, Cyril C. Ramil, Alleni T. Junsay, Benilda S. Ebarvia
Evaluation of performance of chemical laboratories for sulfite mass fraction determination in Philippine export products by proficiency testing

This study assesses the analytical performance of Philippine chemical laboratories in determining sulfite levels in dried mango and desiccated coconut, two major export products. The accuracy-based proficiency testing (PT) schemes, organized by the National Metrology Laboratory of the Philippines, aimed to ensure accurate sulfite measurement for food safety and market acceptance. Participants' performance was evaluated against assigned values obtained using liquid chromatography-isotope dilution mass spectrometry (LC-IDMS). Results showed that 40% (2 of 5) of laboratories achieved satisfactory performance in the dried mango PT, while 75% (3 of 4) succeeded in the desiccated coconut PT. Participation in these PT schemes enabled laboratories to assess and improve their technical capabilities, ensuring more accurate sulfite determination in Philippine export products and supporting food safety and trade compliance.

Ramona Russo, Francesca Rolle, Francesca Durbiano, Francesca Romana Pennecchi, Stefano Pavarelli, Michela Sega
Metrological traceability for measuring Indoor Air Quality using low-cost sensors

Indoor air quality (IAQ) monitoring has gained significant attention due to its impact on human health. Low-cost sensors allow widespread data collection but often lack proper characterisation and standard validation, affecting reliability. The Italian PRIN project "MIRABLE” - Measurement Infrastructure for Research on heAlthy and zero energy Buildings in novel Living lab Ecosystems - led by Italian National Metrology Institute, INRiM, and Politecnico di Torino, aims to develop a measurement infrastructure for monitoring multi-domain indoor environmental conditions using low-cost sensors. In this framework INRiM started activities on the metrological characterization of low-cost sensors for CO2, CO, NOX. For CO₂ sensors, a calibration system using reference gas mixtures ensures metrological traceability, employing a primary reference analyser based on non-dispersive infrared spectroscopy. Exploratory findings and preliminary results with CO2 sensors are detailed in this work and a similar approach is planned for CO and NOX sensors.

Page 4 of 977 Results 31 - 40 of 9762