Hydrocarbon dew point (HCDP) is a critical gas-quality parameter in natural gas transmission and underground storage, because liquid hydrocarbon dropout may affect pipeline integrity, gas metering, and process equipment. This technical note reports preliminary evidence that elevated CO2 content is associated with abnormal HCDP response in operational monitoring data. The underlying dataset comprised 2,377 accepted time-stamped observations grouped into five anonymized campaigns (BV5-1, BV5-2, BV7-1, MR-1, and MR-2). For inferential analysis, campaign-level means were used to avoid pseudo-replication. The full model yielded HCDP = -14.13 + 5.51 · CO2, with R2 = 0.471 and p = 0.201. An exploratory sensitivity analysis excluding the influential BV5-1 campaign yielded HCDP = -22.95 + 8.72 · CO2, with R2 = 0.991 and p = 0.004, but this filtered result is not used as the primary inferential claim. The discussion clarifies analyser measurement principles, proposes a plausible CO2 interference mechanism, compares the observed bias with typical direct-analyser accuracy, and outlines a laboratory validation roadmap using synthetic gas mixtures. The results support the interpretation that the observed effect is operationally important, while also showing that broader controlled validation is still required.
This work focuses on the measurement of small liquid volumes, comparing results obtained using the gravimetric method with different resolutions. The main objective of this study is to characterize the behaviour of microsyringes and micropipettes during the measurement of microvolumes in the range between 0.1 and 1 µL using the gravimetric method, with metrological traceability, and compare the results in the range up to 100 µL. The methodology addresses the challenges associated with measurements below 1 µL by establishing metrological traceability through mass measurement using the gravimetric method. Given that the smallest standard weight is nominally 1 mg, relying solely on the dispensed liquid volume would result in a lack of metrological traceability for volumes under 1 µL. To enhance reliability, eleven independent measurements are taken at each volume point to calculate an average. The results are presented, to conclude the analysis, and simulations were conducted to explore potential improvements by employing a scale with a resolution of 0.001 mg, along with its associated measurement uncertainty.
Low-cost diffuse reflectance coatings were characterized for use on 3D-printed optical assemblies. Barium sulfate (BaSO4) and titanium dioxide (TiO2) suspensions were deposited on polylactic acid (PLA) substrates through a multilayer drop-casting process with an acrylic binder, and compared to commercial white paints and Spectralon® standards. Hemispherical reflectance was measured using an integrating sphere over the 300 nm to 1000 nm range, while angular scattering was assessed from −85° to 85° using a collimated xenon source. BaSO4 achieved the highest broadband performance, with a mean hemispherical reflectance of 98.9 % and a mean angular deviation of 6.3 % from the ideal cosine law. TiO2 showed slightly lower reflectance (96.6 %) and stronger angular directionality, consistent with its smoother and glossier surface finish. Commercial acrylic coatings exhibited markedly lower reflectance (70 % to 86 %) and large deviations from cosine behaviour, while office paper provided good diffusivity but insufficient spectral uniformity. The results demonstrate that a simple BaSO4-based coating can deliver stable, broadband, and highly diffuse reflectance when applied to 3D-printed substrates, enabling the fabrication of low-cost optical diffusers and reflectance references for custom laboratory setups.
Safety concerns surrounding ethoxyquin (EQ), particularly its potential to accumulate as detectable residues in animal-derived foods, underscore the need for rapid and effective analytical methods for EQ monitoring. A new method was developed and validated for the trace determination of ethoxyquin in chicken. The workflow combines the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) approach with dispersive solid phase extraction Enhanced Matrix Removal–Lipid (dSPE EMR-Lipid) cleanup, followed by quantification using liquid chromatography–fluorescence detection (LC-FLD) and isotope dilution tandem mass spectrometry (LC-IDMS/MS). The limits of detection and quantification were 2.4 and 3.6 µg/kg for LC-FLD, and 1.7 and 2.5 µg/kg for LC-IDMS/MS. Both methods exhibited excellent linearity (R = 0.999) using matrix-matched calibration. Mean recoveries across three fortification levels ranged from 94 % to 106 %, while repeatability (RSD ≤ 4.2 %, n = 10) and intermediate precision (RSD ≤ 7.6 %, n = 3) over one-, two-, and three-month periods complied with Horwitz criteria. The developed method was successfully applied to the homogeneity and stability analysis of EQ in a chicken-based reference material.
The paper is related to the assessment of exposure of the general public to extremely low-frequency electromagnetic fields in the vicinity of transmission overhead power lines, based on measurements and calculations of electric and magnetic fields. The uncertainty of electric field strength and magnetic flux density measurement and calculation results is evaluated for a typical 220 kV overhead power line. The most influential uncertainty components and the expanded uncertainties are analysed in detail. Measurement results obtained with two different electromagnetic field analysers are compared with calculation results. Compliance between these results is verified using the number and value. The analysis confirms the validity of both the obtained results and the evaluated expanded uncertainties. The study demonstrates that measurement and calculation uncertainties must be properly considered when assessing compliance with exposure limits. The presented methodology provides reliable results and is particularly important for the accurate evaluation of public exposure to electromagnetic fields, and for demonstrating compliance with the prescribed reference levels.
This paper investigated the microplastic contamination in milkfish harvested from nine mariculture sites in the Philippines. The digestion of microplastics in the gastrointestinal tract (GIT) was carried out using potassium hydroxide (KOH). Optical microscopy (OM) and Fourier transform infrared (FTIR) spectroscopy were utilized to identify and classify the suspected microplastics in the milkfish samples. Results revealed that five types of polymers were identified, namely polyethylene (PE), polypropylene (PP), polyamide (PA), polyethylene and cellulose-based polymers. Sampling site 2 obtained the highest average microplastic concentration of 14.77 + 0.0 particles/fish. This study offers a meaningful contribution to understanding microplastic contamination on tropical aquaculture species and highlights the urgency of implementing effective management strategies to address this escalating environmental concern.
Calibrating high-frequency instruments, such as oscilloscopes and frequency counters, presents significant metrological challenges due to complex and hard-to-validate measurement procedures, limited SI traceability for high-frequency signals, and multiple uncertainty sources. This paper presents the development of uncertainty models for traceable oscilloscope calibration, conducted within the Laboratory for Electrical Measurements at Ss. Cyril and Methodius University in Skopje, aligned with Euramet cg-7 guidelines. Using an originally created software at the Ss. Cyril and Methodius University in Skopje—the MonteCalc Uncertainty Toolkit—the study compares the uncertainty evaluation results obtained according to the GUM (Guide to the Expression of Uncertainty in Measurement) methodology and by the application of the stochastic Monte Carlo method embedded in the MonteCalc Uncertainty Toolkit. These data fusion approaches are applied to experimental data from a high-frequency calibration of diverse types of oscilloscopes for validation purposes. The resulting uncertainty outcomes from both approaches are then used to perform a conformity assessment of the calibrated devices, utilizing integrated decision-making rules within the MonteCalc Uncertainty toolkit, complying with the international guideline ILAC-G8.
This study proposes a smart energy efficiency label (smart label) using blockchain technology to ensure secure access, traceability, validation, and certification of all information related to the energy performance of labeled equipment. The methodology involves mapping the process of using the PROCEL (National Electric Energy Conservation Program) label on a typical household appliance within the Brazilian Labelling Program (PBE), showing the application of blockchain technology throughout the process. With the PROCEL label, blockchain can document the entire lifecycle of the equipment, tracking every step until it reaches the consumer. This allows consumers to trace and verify the results of tests the equipment has undergone, make comparisons between various products, understand the ecological impact of the product's development, and ensure that the product is not counterfeit. Labels, logos, and quality descriptions reduce information asymmetry regarding product quality, providing consumers with greater confidence in their purchases. Blockchain technology addresses each of these aspects by enabling traceability, certification, verification, and security of the information presented on the equipment. The smart label holds significant potential to enhance agility, transparency, security, interoperability, auditability, reliability, and product traceability, thus benefiting both consumers and manufacturers by fostering trust and promoting the production of more energy-efficient products.
The integration of physical and virtual reality is gaining increasing relevance, especially in contexts where the interaction between users and digital environments is essential. Virtual reality (VR) enables the simulation of sensory experiences, opening up new opportunities in fields such as industrial training. The quality of simulations depends on how accurately the virtual world replicates the behavior of real objects and the tactile feedback provided to users. Haptic gloves, which deliver tactile sensations during interaction with virtual objects, are among the most advanced tools in this field. This study focuses on characterizing the feedback parameters of the Senseglove Nova and Nova 2 haptic gloves, with the aim of optimizing the user–environment interaction in virtual reality. The primary objective of this study was to characterize the feedback parameters of Senseglove Nova and Nova 2 in virtual environments, with emphasis on identifying differences in object grasping between real and virtual conditions. In this context, angular data from hand movements in both real and virtual scenarios were analyzed and compared to verify their accuracy and enhance interaction with the virtual environment. The proposed methodology establishes a quantitative framework for evaluating haptic feedback accuracy, offering practical insights for the design of immersive training systems.
Compact multi-spectral sensors present a cost-effective solution for portable light measurement, yet their radiometric accuracy and spectral reconstruction capabilities remain under-characterised compared to laboratory-grade spectroradiometers. This study presents a systematic method for evaluating and calibrating a commercial sensor with a discrete set of spectral channels. The absolute radiometric responsivity was characterized using both laboratory-standard and readily accessible illumination sources, thereby demonstrating that the calibration is independent of the particular light source. Furthermore, the spectral power distribution reconstruction was evaluated under various illumination conditions, correctly estimating radiometric and photometric quantities for visual and non-visual systems. The results also show that increasing the number of spectral channels improves reconstruction accuracy primarily when the channels are well distributed over the spectral range, while additional overlapping bands provide only marginal benefits. This work is a step towards unified methodologies and infrastructure for standardised measurement tools and reproducible calibration.
Adverse weather conditions continue to present a significant challenge for Advanced Driver Assistance Systems (ADAS). Quantification of visibility in fog is typically accomplished by measuring the Meteorological Optical Range (MOR). Despite the MOR's extensive recognition and utilisation across diverse domains, including aviation, navigation, and traffic management, there exists a potential discrepancy between the visibility estimated using the MOR, i.e. the optical path length in the atmosphere necessary to diminish the luminous flux of a collimated beam to 5 percent of its original value, and that actually perceived by drivers or camera-based ADAS systems operating within the visible range. Indeed, the anisotropy of the scattering generated by fog particles, in conjunction with the fact that, in the automotive sector, visibility is generally supported by the headlights and street lighting, can lead to phenomena not considered by the MOR. The present study proposes a measurement method and setup for investigating the degree to which visibility estimated exploiting the MOR represents the visibility perceived by drivers or camera-based ADAS systems. The experimental findings indicate that the lighting angle can substantially influence visibility. Thus, the study will propose a simplified analysis to identify the primary contributors to this discrepancy.
This study investigates the performance of a protective coating composed of a commercial polysiloxane mixed with titanium dioxide nanoparticles (P25), applied onto terracotta samples via airbrushing. The coating was characterized through colorimetric analysis, static contact angle (SCA) measurements, and infrared spectroscopy to evaluate its aesthetic impact, wettability properties, and chemical stability under UV exposure. Results indicate that both polysiloxane alone and the polysiloxane-titania formulation altered the appearance of terracotta samples, with a ΔE* value of approximately 3. Polysiloxane alone induced a yellowing effect, while the addition of titanium dioxide led to surface whitening. Accelerated aging did not cause significant aesthetic degradation, suggesting good visual durability. As expected, the strong artificial aging process induced the loose of superhydrophobic coating and its water repellency from 136° to 16° SCA values, changing to a hydrophilic state due to increased surface energy. ATR infrared spectroscopy revealed UV-induced polymer aging (segment scission or crosslinking) which may have contributed to these changes. These characteristics make the polymer more suitable for indoor surfaces, characterized by low-irradiance environments, or as a temporary protective treatment for artifacts requiring subsequent restoration intervention. These limitations observed with the commercial product have guided ongoing research in our group toward an eco-friendly formulation with significantly improved UV resistance, tailored for long-term heritage conservation needs.
In this study, a method for the analysis of mercury (Hg) content in Philippine milkfish (Chanos chanos) 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, which resulted in a recovery ranging between 93 % and 104 %. Additionally, the relative standard deviation (RSD) of the collected dataset is lower than 10% and the expanded uncertainty is 0.08 ppm, showing the method’s precision and consistency. For confirmation, DORM-5 was analyzed, resulting in 98.885 % Hg recovery, further supporting the capability of the TXRF analysis. The method was applied to milkfish samples harvested from different areas around Laguna de Bay to screen for the presence of Hg contamination. The dorsal meat of each milkfish sample was separated, dried, and crushed into smaller particles for TXRF analyses. The analyses showed that no mercury was detected in the milkfish samples which indicates that the milkfish from Laguna de Bay are free from harmful levels of Hg contamination.
Polyethylene films are widely used as food-contact packaging materials, yet migration behaviour can vary depending on polymer structure, thermal properties, and food simulant conditions. This study evaluated the migration of UV-absorbing contaminants from commercially available polyethylene packaging films, using an integrated structure–property–migration approach. Fourteen polyethylene films collected from the local market were classified as LDPE-like or HDPE-like based on FTIR spectral features associated with chain structure, while thermal behaviour and degree of crystallinity were determined using differential scanning calorimetry. Preliminary migration screening was conducted using ethanol-based food simulants under controlled conditions, with 20 % ethanol applied as a more aggressive simulant relative to the earlier screening performed using 8 % ethanol. Migration responses were assessed using UV–VIS spectrophotometry as a comparative screening tool. FTIR and DSC analyses revealed substantial structural and thermal variability among the films, with crystallinity values ranging from approximately 10 % to 50 %. Migration screening responses showed broader variability among some lower-crystallinity films, however, exploratory analysis indicated that crystallinity alone did not fully explain the observed responses. Overall, the findings demonstrate the complexity of structure–property–migration relationships in commercial polyethylene packaging films, and highlight the value of integrating spectroscopic, thermal, and screening-based analytical approaches for comparative migration evaluation.
This study presents a 29-day field deployment of a HORIBA photocatalytic self-cleaning pH electrode for continuous wastewater monitoring in a full-scale treatment facility discharging into Laguna Lake, Philippines. The system generated 41,729 valid one-minute pH measurements between 11 December 2025 and 9 January 2026 with near-continuous uptime. The work focuses on uncertainty-oriented operational indicators derived from grouped observations, rather than on a complete formal Guide to the Expression of Uncertainty in Measurement (GUM) uncertainty budget. Statistical indicators included agreement with laboratory reference measurements, rolling median absolute deviation (MAD), grouped daily statistics, trend analysis, and distributional behavior. Laboratory reference measurements were obtained using a benchtop HORIBA pH meter, calibrated with buffer standards traceable to the National Institute of Standards and Technology (NIST). The results indicated low short-term variability, operationally stable variance behavior, preserved sensitivity to transient process events, and no evidence of uncontrolled sensor degradation during deployment. Type A and Type B uncertainty contributions were discussed qualitatively within a grouped-observation framework consistent with JCGM 100:2008 Appendix H.5. The observed temporal behavior was more consistent with gradual process evolution than with fouling-induced sensor instability. Future investigations include deployment in multiple scenarios for inter-electrode reproducibility, parallel experiments with controlled environments, and extended and multi-season temporal studies.
This study evaluated the migration of total UV-absorbing contaminants (TACs) from polypropylene (PP) microwavable containers in the Philippines under food-contact conditions relevant to regulatory screening and local use. Previously developed UV-Vis spectrophotometric methods for polyethylene (PE) food packaging were applied to PP matrices using water and 20 % ethanol as simulants for aqueous and alcoholic foods. Migration profiles were then compared with earlier data for fatty and oily foods, while selected PP samples were subjected to varying contact times and temperatures. The results showed that TAC migration from PP microwavable containers remained below the FDA Philippines maximum allowable limits (MALs). Absorbance values were strongly and positively correlated with both contact time and temperature. The findings extend previous screening studies by broadening the range of food simulants and contact conditions evaluated and by providing additional evidence for risk-based assessment of plastic food contact articles in the local setting. Further work should include acidic and dry food simulants, compound-specific identification, longer storage simulations, and direct microwave exposure studies.
The measurement of the actual shape of a sail during navigation is an important issue both for skippers and sail makers. Besides sophisticated optical approaches based on artificial vision or based on the use of fiber optics glued within a sail, we propose to directly measure the mainsail's draft by means of a full bridge strain gauge (specifically designed for this application on PCB) applied on the two sides of a fiber glass batten into an horizontal section of the sail. The proposed approach reveals to be accurate enough and has the benefits of a cheap implementation so that it can be used not only by racing yachts and sail makers but also by leisure yachts owners. Moreover, thanks to the wireless data transmission, the proposed system can be easily integrated in a network of multiple sensors completing in this way the set of navigation data.
Continuous monitoring of blood pCO2 is critical during extracorporeal circulation (ECC) to support clinical decision-making. This study aims to describe and investigate a new, low-cost, disposable fluorescent pCO2 sensor, namely MS2. The performance of MS2 is analysed by comparison with a blood gas analyzer. A significant challenge in developing sensors for in vivo applications is ensuring biocompatibility. In the MS2 sensor, biocompatibility is ensured by using a medical-grade gas-permeable membrane that isolates the sensing chemistry from the patient’s blood. The study also investigates the performance of a commercial optical pCO2 sensor, the PreSens MCR-O1P1C1, which is not approved for use with blood. The aim is to assess the feasibility of employing the PreSens MCR-O1P1C1 for blood monitoring in scenarios where biocompatibility is not a prerequisite, such as in the development stages of biomedical devices that require ex vivo blood testing. The results obtained during a 6.5-hour test with bovine blood demonstrate that both measuring systems can provide valid support for monitoring pCO2 in blood. However, despite its excellent response times, the off-label application of the PreSens MCR-O1P1C1 necessitates an adjustment of the measuring system to prevent significant measurement errors. Thus, these results position MS2 as a promising solution for real-time, in-line blood gas monitoring in ECC procedures.
