Search Results (21)

Deoxidized high-phosphorus (DHP) copper is widely used in marine heat-exchangers and seawater piping, where long-term structural reliability demands both high strength and a deformation-tolerant microstructure to resist damage initiation. Constrained groove pressing (CGP) is a scalable severe plastic deformation route for metallic sheets; however, the sharp trapezoidal junctions of the conventional die impose parasitic bending strains that produce sinusoidal in-plane hardness variations and anisotropic properties. This study introduces a modified CGP (MCGP) process in which the sharp crest and valley of each 45° tooth are replaced by tangent circular arcs (R₁ = 1.6 mm at the crest, R₂ = 4.8 mm at the valley), removing geometric discontinuities while exactly preserving the groove angle, pitch, and die envelope for drop-in compatibility with existing equipment. DHP copper sheets processed by conventional CGP and MCGP were systematically compared using optical microscopy, SEM, XRD, microhardness, tensile testing, and finite-element analysis. MCGP delivered exceptional mechanical performance: yield strength of 281.19 MPa, ultimate tensile strength of 451.94 MPa (96.4% above the as-received state and 23.8% above conventional CGP), mean hardness of 131.38 HV, and the finest apparent (instrument-uncalibrated) coherent diffraction-domain size of 22.75 nm. Finite-element modelling revealed a lower peak equivalent plastic strain with a more continuously distributed through-thickness deformation path, despite an unchanged nominal grooving strain (≈0.56). Notably, while the modified die redistributes deformation rather than amplifying the nominal strain, the measured through-thickness hardness inhomogeneity factor increased from 7.14% to 21.97% due to strain concentration in the mid-thickness region, indicating that full homogenisation requires further arc-radius optimisation. Nevertheless, the substantial gains in strength and microstructural refinement demonstrate that MCGP offers a promising processing route for producing DHP copper components with enhanced strength and refined microstructures, which may contribute to improved damage tolerance. However, it is acknowledged that direct tests on seawater corrosion, corrosion fatigue, and thermal cycling were not performed in this study; the implications for marine service life are inferred from the established literature on the benefits of grain refinement for corrosion and fatigue resistance. Future work incorporating marine environmental performance tests is recommended to validate these implications. Full article

Radon (²²²Rn) is a chemically inert (noble) gas, naturally occurring α-emitter radionuclide, and the direct progeny of ²²⁶Radium; it is produced in the uranium (²³⁸U) decay chain. Short-term measurements of the concentration of radon can be performed to identify locations and objects with potentially increased concentrations. The goal of this study is to present a comparison of models for the seasonal prediction of ²²²Rn active concentration variations from the results of ²²²Rn short-term measurements acquired by active instruments. Several predictive models are compared in this study, with estimation and validation datasets from ²²²Rn concentration measurements from two significant micro-locations: the St. Barbara mine and a ground-floor room of the University of Zagreb Faculty of Mining, Geology and Petroleum engineering (UNIZG-FMGPE) building, in Zagreb, Croatia. MATLAB version R2025b System identification and a Signal multiresolution analyzer were used for the estimation of predictive models and validation for mid-term prediction. This research provides one method for estimating the concentration variations from a smaller number of observations from 8 days of measurements. It shows that the best models for the estimation and prediction of radon concentration time series are the auto-regressive non-linear ARX model (NLarx), with a one-step-ahead prediction fit of up to around 90% for a minimum measurement duration of 8 days, 192 samples, and a 1 h floating mean for the estimation and ARMAX estimation from the reconstructed signal as a simple polynomial approximation of the original measurement signal, with a one-step-ahead prediction fit of almost 100%. The ARMAX model with a one-step-ahead predicted output gives excellent estimation of the MODWT and EMD reconstructed signal, which has approximately the same mean as the original signal and, thus, can be used for indirect prediction of the Rn mean. The NLarx model showed good results in the validation of Rn concentration variations; thus, this model is selected as the preferred model to predict Rn concentration variations from short-term measurements. Full article

Monitoring dissolved carbon dioxide (CO₂) in aquatic and sediment systems is critical for understanding carbon cycling and climate feedback. This study develops and characterizes a compact, low-cost microbolometer-based attenuated total reflectance (ATR) mid-infrared sensor for direct dissolved CO₂ measurement in liquid and soil-water environments. The system integrates a ZnSe ATR crystal with custom suspended SiN membrane microbolometers and uses evanescent-wave absorption at 4.26 μm with a broadband LED source and computational spectral reconstruction, eliminating the need for an interferometer. Calibration shows excellent linearity (R² ≈ 0.99) over 50–1000 ppm CO₂, with a practical limit of detection (LOD) of ~26–35 ppm at 5–25 °C. UV-induced CO₂ generation from soil-water mixtures was investigated across UV wavelengths, revealing UV-C (254 nm) as optimal, producing net ΔCO₂ ≈ 339 ppm above ambient levels in 30 min. Environmental factors (temperature 5–35 °C, pH 5–11, pressure 1–1.5 ATM, dissolved organic carbon) were systematically evaluated, confirming robust sensor performance (accuracy >90%, correlation r > 0.98 with reference instrument). This sensor represents the first integration of MEMS microbolometer detectors with ATR evanescent-wave spectroscopy for liquid-phase dissolved CO₂, enabling real-time monitoring and rapid sediment organic carbon assessment in a field-deployable platform. Full article

Wind is one of the main environmental loads acting on temporary scaffolding structures, yet current design codes apply simplified assumptions regarding its distribution. This study presents full-scale measurements of wind velocities on 10 façade scaffolds located across Poland, representing various building geometries and exposure conditions. Each scaffold was instrumented with five two-dimensional ultrasonic anemometers and one three-dimensional rooftop reference anemometer. Data were analysed in 10 min averages, divided into 30° directional sectors and compared with the normative model defined in EN 12811-1 using the site factor $c_s$. The results reveal strong spatial variability of wind action across scaffold surfaces, with measured local velocities ranging from 20% to 140% of the reference values. The parallel flow component exhibited substantial scatter, while the perpendicular component was strongly damped by façade shielding and protective netting. For most mid-façade positions, measured values corresponded to $c_s=0.25–0.5$, whereas corner and edge locations frequently exceeded $c_s=1.0$. The findings demonstrate that the uniform site factors assumed in current standards do not capture the aerodynamic complexity of real scaffolds, especially under oblique or high-intensity wind conditions. The presented dataset provides a unique experimental basis for improving scaffold wind load modelling and developing position-specific design provisions. Full article

Water loss during storage is a major cause of postharvest quality deterioration in cucumber, yet existing methods to monitor hydration are often destructive or require expensive instrumentation. We developed a low-cost, non-destructive approach for estimating fruit relative water content (RWC) using visible-light color imaging combined with an ensemble machine-learning model (Random Forest). A total of 1200 fruits were greenhouse-grown, harvested at market maturity, and equally divided between optimal and ambient storage temperature (10 and 25 °C, respectively). Digital images were acquired at harvest and at 7 d intervals during storage, and color parameters from four standard color systems (RGB, CMYK, CIELAB, HSV) were extracted separately for the neck, mid, and blossom regions as well as for the whole fruit. During storage, fruit RWC decreased from 100% (fully hydrated condition) to 15.3%, providing a broad dynamic range for assessing color–hydration relationships. Among the 16 color features evaluated, the mean cyan component (μC) of the CMYK space showed the strongest relationship with measured RWC (R² up to 0.70 for whole-fruit averages), reflecting the cyan region’s heightened sensitivity to dehydration-induced changes in pigments, cuticle properties and surface scattering. The Random Forest regression model trained on these features achieved a higher predictive accuracy (R² = 0.89). Predictive accuracy was also consistently higher when μC was calculated over the entire fruit surface rather than for individual anatomical regions, indicating that whole-fruit color information provides a more robust hydration signal than region-specific measurements. Our findings demonstrate that simple visible-range imaging coupled with ensemble learning can provide a cost-effective, non-invasive tool for monitoring postharvest hydration of cucumber fruit, with direct applications in quality control, shelf-life prediction and waste reduction across the fresh-produce supply chain. Full article

The study aims to recover, interpret, and analyze the daily meteorological observations made in Venice by Tommaso Temanza from 1751 to 1769. These records are relevant because they provide direct information about the climate of the Little Ice Age. Temanza used a barometer, an air thermometer of Amontons’ type, and an additional mercury thermometer, i.e., Réaumur’s thermometer. These early instruments are presented and discussed in this study. The barometer readings needed standard corrections, which were unknown at that time. The scale of the air thermometer was arbitrary, and temperatures were measured in inches of mercury. For the Amontons thermometer, Temanza missed the calibration points and used a particular scale with the zero-point in the middle of the range. He gave two contradictory explanations for this choice, both of which are discussed in this paper. In the 18th century, the use of a singular value to represent the average temperature, called “Temperate”, was promoted by Michieli du Crest in Geneva and Toaldo in Padua. This work reconstructs the unknown scale, using contemporary observations by Giovanni Poleni and Giuseppe Toaldo in Padua (30 km west of Venice) and snowfall reported in the weather notes to determine the temperature point at 0 °C. A discussion is made about the calibration, validation, and conversion of readings from the original to modern units of pressure and temperature, i.e., hPa and °C, respectively. The recovered record of Venice is presented in comparison with Padua, Bologna, and Milan. The paper provides and analyzes the new dataset, and improves knowledge about the climate, history of science, instruments, and observations made in the mid-18th century. Full article

Redox metabolism is an integral part of the glutathione system, encompassing reduced and oxidized glutathione, hydrogen peroxide, and associated enzymes. This core process orchestrates a network of thiol antioxidants like thioredoxins and peroxiredoxins, alongside critical thiol-containing proteins such as mercaptoalbumin. Modifications to thiol-containing proteins, including oxidation and glutathionylation, regulate cellular signaling influencing gene activities in inflammation and carcinogenesis. Analyzing thiol antioxidants, especially glutathione, in biological fluids offers insights into pathological conditions. This review discusses the analytical methods for biothiol determination, mainly in blood plasma. The study includes all key methodological aspects of spectroscopy, chromatography, electrochemistry, and mass spectrometry, highlighting their principles, benefits, limitations, and recent advancements that were not included in previously published reviews. Sample preparation and factors affecting thiol antioxidant measurements are discussed. The review reveals that the choice of analytical procedures should be based on the specific requirements of the research. Spectrophotometric methods are simple and cost-effective but may need more specificity. Chromatographic techniques have excellent separation capabilities but require longer analysis times. Electrochemical methods enable real-time monitoring but have disadvantages such as interference. Mass spectrometry-based approaches have high sensitivity and selectivity but require sophisticated instrumentation. Combining multiple techniques can provide comprehensive information on thiol antioxidant levels in biological fluids, enabling clearer insights into their roles in health and disease. This review covers the time span from 2010 to mid-2024, and the data were obtained from the SciFinder^® (ACS), Google Scholar (Google), PubMed^®, and ScienceDirect (Scopus) databases through a combination search approach using keywords. Full article

Background: Neck circumference (NC) has been proposed as an indicator of upper trunk adiposity and a potential indicator of metabolic risk. The objective was to evaluate NC and its correlation with body fat percentage (BF%) and other indicators of adiposity in children with normal weight, overweight, and obesity. Methods: In a cross-sectional study, 112 children 5 to 10 years of age were included in the outpatient clinic from a public hospital. Measures of weight and height to calculate BMI (kg/m²), NC, mid-upper arm circumference, waist circumference, and tricipital skinfold thickness. Body composition measurements were performed using an electrical bioimpedance device (BIA). The relationship between anthropometric variables and BF% obtained by BIA was determined using Spearman correlation tests. Multivariate models were constructed with BF% as the dependent variable and anthropometric parameters as independent. Results: In the entire group, there was a direct correlation between NC and BF% (r = 0.50, p < 0.001), but lost statistical significance in the case of normal weight. The relationship maintained its significance in subjects from the overweight and obesity groups. In multivariate models, BMI exhibited the highest correlation with BF%, followed by waist circumference and mid-upper arm circumference; for NC, the R² value was 0.30 (p < 0.001). Conclusions: Neck circumference is useful in the screening of population groups with the advantage of not requiring any specialized instruments for its measurement other than a tape measure. BMI and waist circumference were the best indicators of general and central adiposity, respectively. Full article

The global navigation satellite system (GNSS) precise point positioning (PPP) technique has been commonly applied to structural displacement monitoring. Considering the sheltering effect, GNSS receivers are regularly mounted on the top of a structure, but the structure is often not a rigid body; therefore, the receiver should also be mounted on the wall of the structure. Combining five constellations, GNSS can effectively reduce the sheltering effect. Therefore, this study attempts to apply the five-constellation PPP technique to monitor structural long-term displacements on the wall (SLDW) and structural vibrational displacements on the wall (SVDW) and then analyze their performance. Two novel methods are proposed in monitoring SVDW. Firstly, semi-generated measurements are designed to generate pseudo-environments with vibrations for the receiver. Therefore, additional instruments are not necessary to generate vibrations. Secondly, to further reduce the sheltering effect, a position-constrained PPP (PCPPP) model is developed. Formal performance analyses are presented in this study, and the results show that using the five-constellation PPP to monitor SLDW and SVDW in the horizontal direction is possible as long as the sheltering effect over the half sky of the receiver is not severe. In monitoring SVDW, the PCPPP model can perform better than the classical PPP model and be successful in the horizontal direction when the condition of elevation cutoff is given as high as 50°. For Asia-Pacific mid-low-latitude regions, the global positioning system (GPS) and BeiDou system (BDS) are important to maintain the availability of monitoring SVDW. Full article

The records of the Advanced Very High Resolution Radiometer (AVHRR) instrument observations can resolve the current lack of a long global climate data record of Reflected Solar Flux (RSF), by transforming these measurements into broadband flux at the top-of-atmosphere. This paper presents a methodology for obtaining daily mean RSF (Wm${}^{-2}$) from AVHRR. First, the narrowband reflectances are converted to broadband reflectance using empirical regressions with the Clouds and the Earth’s Radiant Energy System (CERES) observations. Second, the anisotropy is corrected by applying Angular Distribution Models (ADMs), which convert directional reflectance into a hemispherical albedo. Third, the instantaneous albedos are temporally interpolated by a flexible diurnal cycle model, capable of ingesting any number of observations at any time of day, making it suitable for any orbital configuration of NOAA and MetOp satellites. Finally, the twilight conditions prevailing near sunrise and sunset are simulated with an empirical model. The entire day is then integrated into a single daily mean RSF. This paper furthermore demonstrates the methodology by validating a full year (2008) of RSF daily means with the CERES SYN1deg data record, both on daily and subdaily scale. Several configurations are tested, each excluding particular satellites from the constellation in order to mimic orbital changes (e.g., orbital drift), and to assess their relative importance to the daily mean RSF. The best performance is obtained by the combination of at least one mid-morning (NOAA-17 or MetOp-A) and one early afternoon (NOAA-18) orbit. In this case, the RMS difference with CERES is about 7 Wm${}^{-2}$. Removing NOAA-18 degrades the performance to an RMS difference of 12 Wm${}^{-2}$, thereby providing an estimate of the impact of NOAA-19’s orbital drift between 2016 and 2020. Very early or late observations (NOAA-15, NOAA-16) provide little added value, and both mid-morning orbits turn out to be almost interchangeable given their close temporal proximity. Full article

As one of the most sensitive instruments for deformation monitoring in geophysics, borehole strainmeter has the capability to record a large spectrum of tectonic and environmental signals. Sensors are usually deployed near active faults and volcanoes and provide high-resolution continuous recordings of seismic and aseismic signals, hydrological variations (rainfall, groundwater level) and natural hazards (tropical cyclones, landslides, tsunamis). On the occasion of the 50th anniversary of the installation of the first Sacks–Evertson borehole strainmeter, in central Japan, we present an overview of the major scientific contributions and advances enabled by borehole strainmeter measurements in Taiwan since their installation in the mid 2000s. We also propose a set of future research directions that address recent challenges in seismology, hydrology and crustal strain modeling. Full article

Background and Objectives: Acquiring knowledge about the magnitude and direction of induced joint forces during modifying gait strategies is critical for proper exercise prescription. The present study aimed to evaluate whether a heel-first strike pattern during gait can affect the biomechanical characteristics of ankle and knee joints among asymptomatic people. Materials and Methods: In this cross-sectional study performed in the biomechanics laboratory, 13 professional healthy male athletes walked on an instrumented walkway under two walking conditions. For the normal condition, subjects were instructed to walk as they normally would. For the heel-first strike condition, subjects were instructed to walk with heel-first strike pattern and increase heel contact duration as much as possible. Then, knee and ankle joint range of motions and moments, as well as vertical ground reaction force was measured by the Kistler force plate and Vicon motion analysis system. Results: Knee flexion angle at the initial contact and during stance phase was significantly lower when increasing the heel strike pattern. In addition, the mean values of the knee external rotation and adductor moments during heel strike condition were lower than those in normal walking. Further, the ankle dorsiflexion range of motion (ROM) during mid-stance increased significantly during heel-first strike pattern compared to the value in normal gait pattern. Conclusions: The modification of gait pattern including heel-first strike pattern can reduce the mechanical load applied to the knee, while improving the extensibility of gastro-soleus muscle complex. Full article

Nitrogen dioxide (NO${}_2$) is a major tropospheric air pollutant. Its concentration in the atmosphere is most frequently monitored indirectly by chemiluminescence detection or using direct light absorption in the visible range. Both techniques are subject to known biases from other trace gases (including water vapor), making accurate measurements at low concentration very challenging. Selective measurements of NO${}_2$ in the mid-infrared have been proposed as a promising alternative, but field deployments and comparisons with established techniques remain sparse. Here, we describe the development and validation of a quantum cascade laser-based spectrometer (QCLAS). It relies on a custom-made astigmatic multipass absorption cell and a recently developed low heat dissipation laser driving and a FPGA based data acquisition approach. We demonstrate a sub-pptv precision (1 $\sigma$) for NO${}_2$ after 150 s integration time. The instrument performance in terms of long-term stability, linearity and field operation capability was assessed in the laboratory and during a two-week inter-comparison campaign at a suburban air pollution monitoring station. Four NO${}_2$ instruments corresponding to three different detection techniques (chemiluminescence detection (CLD), cavity-attenuated phase shift (CAPS) spectroscopy and QCLAS) were deployed after calibrating them with three different referencing methods: gas-phase titration of NO, dynamic high-concentration cylinder dilution and permeation. These measurements show that QCLAS is an attractive alternative for high-precision NO${}_2$ monitoring. Used in dual-laser configuration, its capabilities can be extended to NO, thus allowing for unambiguous quantification of nitrogen oxides (NO${}_x$), which are of key importance in air quality assessments. Full article

The development of rapid and accurate biomedical laser spectroscopy systems in the mid-infrared has been enabled by the commercial availability of external-cavity quantum cascade lasers (EC-QCLs). EC-QCLs are a preferable alternative to benchtop instruments such as Fourier transform infrared spectrometers for sensor development as they are small and have high spectral power density. They also allow for the investigation of multiple analytes due to their broad tuneability and through the use of multivariate analysis. This article presents an in vitro investigation with two fiber-coupled measurement setups based on attenuated total reflection spectroscopy and direct transmission spectroscopy for sensing. A pulsed EC-QCL (1200–900 cm ${}^{-1}$ ) was used for measurements of glucose and albumin in aqueous solutions, with lactate and urea as interferents. This analyte composition was chosen as an example of a complex aqueous solution with relevance for biomedical sensors. Glucose concentrations were determined in both setup types with root-mean-square error of cross-validation (RMSECV) of less than 20 mg/dL using partial least-squares (PLS) regression. These results demonstrate accurate analyte measurements, and are promising for further development of fiber-coupled, miniaturised in vivo sensors based on mid-infrared spectroscopy. Full article

The basis for the designing of water supply devices is knowledge of the distribution of water demand. The only practical tool that utility companies can use to measure water consumption is water meters. The literature part of the article compares the guidelines for the devices contained in the following directives: EEC (European Economic Community—withdrawn) and Measuring Instruments Directive—MID (applicable at present). The methodology of selecting water meters in accordance with previous and current regulations was also presented. The main purpose of this work was to determine the structure of water demand for selected building objects. Differences between real and literature values of water flows and water demand were determined. It was found that the average consumption in the analyzed buildings was higher then the consumption in Polish Regulation and in the town of Dabrowa Gornicza. The highest level of demand was in the buildings, which were equipped with automatic watering systems. The maximum momentary volumetric flows are also shown. Based on the obtained data, the accuracy of the water meters selection was checked. The calculated daily and hourly peak factors were compared with the values from the literature. The analysis was performed based on current legal acts, technical literature and data obtained from Dabrowskie Wodociagi Sp. z o.o. in Dabrowa Gornicza, Poland. Full article