Continuous Real-time Measurement Research Articles

Simple retrieval of the real part of the refractive index for ambient aerosols using extinction coefficient analysis via camera and volume size distribution

This study explored a novel approach for estimating the variations in the refractive index (RI) of aerosols, which is a crucial optical parameter that contains information about particle scattering and absorption. RI is often subject to constraints related to observation time, wavelength selection, and analysis methods. To overcome these limitations, we employed real-time continuous measurements using a camera and optical particle counter (OPC) equipment and applied optimization techniques based on the Mie theory to reverse-calculate changes in the refractive index. Our methodology uses a camera to measure the aerosol extinction coefficients at three different wavelengths within the RGB spectrum (597 nm, 534 nm, and 459 nm), whereas OPC observations provide information on particle size distribution (0.127–17.58 μm as radius). Because the extinction efficiency at known wavelengths varies with the refractive index according to the Mie theory, we retrieved the refractive index, which is an unknown variable, from the extinction coefficient equation. We focused on the real part of the RI because it is challenging to discern the imaginary part of the RI from the visible wavelengths. Our observations were conducted in areas near Busan Harbor and in mixed residential regions. The real part of the RI was determined to be 1.53 ± 0.12. During periods of observed dust events, the refractive index's real part was 1.62 ± 0.05, while during periods anticipated to have emissions of fine aerosols, it was 1.51 ± 0.10. The retrieved RI fell within a range similar to that in other studies, and the changes in the refractive index showed meaningful patterns when analyzed for variations in the particle size distribution and changes in the scattering coefficient. This approach has the potential to advance our understanding of aerosol optical properties and can be applied to real-time analyses with a relatively simple equipment setup, thereby opening new possibilities for its use as a critical variable in optical measurements and environmental models.

Clinical Biochemistry of Serum Troponin.

Accurate measurement and interpretation of serum levels of troponin (Tn) is a central part of the clinical workup of a patient presenting with chest pain suspicious for acute coronary syndrome (ACS). Knowledge of the molecular characteristics of the troponin complex and test characteristics of troponin measurement assays allows for a deeper understanding of causes of false positive and false negative test results in myocardial injury. In this review, we discuss the molecular structure and functions of the constituent proteins of the troponin complex (TnT, TnC, and TnI); review the different isoforms of Tn and where they are from; survey the evolution of clinical Tn assays, ranging from first-generation to high-sensitivity (hs); provide a primer on statistical interpretation of assay results based on different clinical settings; and discuss potential causes of false results. We also summarize the advances in technologies that may lead to the development of future Tn assays, including the development of point of care assays and wearable Tn sensors for real-time continuous measurement.

Quantification of blood flow index in diffuse correlation spectroscopy using a robust deep learning method.

Diffuse correlation spectroscopy (DCS) is a powerful, noninvasive optical technique for measuring blood flow. Traditionally the blood flow index (BFi) is derived through nonlinear least-square fitting the measured intensity autocorrelation function (ACF). However, the fitting process is computationally intensive, susceptible to measurement noise, and easily influenced by optical properties (absorption coefficient and reduced scattering coefficient ) and scalp and skull thicknesses. We aim to develop a data-driven method that enables rapid and robust analysis of multiple-scattered light's temporal ACFs. Moreover, the proposed method can be applied to a range of source-detector distances instead of being limited to a specific source-detector distance. We present a deep learning architecture with one-dimensional convolution neural networks, called DCS neural network (DCS-NET), for BFi and coherent factor () estimation. This DCS-NET was performed using simulated DCS data based on a three-layer brain model. We quantified the impact from physiologically relevant optical property variations, layer thicknesses, realistic noise levels, and multiple source-detector distances (5, 10, 15, 20, 25, and 30mm) on BFi and estimations among DCS-NET, semi-infinite, and three-layer fitting models. DCS-NET shows a much faster analysis speed, around 17,000-fold and 32-fold faster than the traditional three-layer and semi-infinite models, respectively. It offers higher intrinsic sensitivity to deep tissues compared with fitting methods. DCS-NET shows excellent anti-noise features and is less sensitive to variations of and at a source-detector separation of 30mm. Also, we have demonstrated that relative BFi (rBFi) can be extracted by DCS-NET with a much lower error of 8.35%. By contrast, the semi-infinite and three-layer fitting models result in significant errors in rBFi of 43.76% and 19.66%, respectively. DCS-NET can robustly quantify blood flow measurements at considerable source-detector distances, corresponding to much deeper biological tissues. It has excellent potential for hardware implementation, promising continuous real-time blood flow measurements.

Diel variability of carbon dioxide concentrations and emissions in a largest urban lake, Central China: Insights from continuous measurements

Accurately quantifying the carbon dioxide (CO2) emissions from lakes, especially in urban areas, remains challenging due to constrained temporal resolution in field monitoring. Current lake CO2 flux estimates primarily rely on daylight measurements, yet nighttime emissions is normally overlooked. In this study, a non-dispersive infrared CO2 sensor was applied to measure dissolved CO2 concentrations over a 24-h period in a largest urban lake (Tangxun Lake) in Wuhan City, Central China, yielding extensive data on diel variability of CO2 concentrations and emissions. We showed the practicality and efficiency of the sensor for real-time continuous measurements in lakes. Our findings revealed distinct diurnal variations in CO2 concentrations (Day: 38.58 ± 23.8 μmol L−1; Night: 42.01 ± 20.2 μmol L−1) and fluxes (Day: 7.68 ± 10.34 mmol m−2 d−1; Night: 9.68 ± 9.19 mmol m−2 d−1) in the Tangxun Lake. The balance of photosynthesis and respiration is of utmost importance in modulating diurnal CO2 dynamics and can be influenced by nutrient loadings and temperature. A diel variability correction factor of 1.14 was proposed, suggesting that daytime-only measurements could underestimate CO2 emissions in urban lakes. Our data suggested that samplings between 11:00 and 12:00 could better represent the average diel CO2 fluxes. This study offered valuable insights on the diel variability of CO2 fluxes, emphasizing the importance of in situ continuous measurements to accurately quantify CO2 emissions, facilitating selections of sampling strategies and formulation of management strategies for urban lakes.

Development of a Real-Time Continuous Measurement System for Tree Radial Direction

Development of a Real-Time Continuous Measurement System for Tree Radial Direction

A Spectrofluorometric Method for Real-Time Graft Assessment and Patient Monitoring.

Biomarkers are powerful clinical diagnostics and predictors of patient outcome. However, robust measurements often require time and expensive laboratory equipment, which is insufficient to track rapid changes and limits direct use in the operating room. Here, this study presents a portable spectrophotometric device for continuous real-time measurements of fluorescent and non-fluorescent biomarkers at the point of care. This study measures the mitochondrial damage biomarker flavin mononucleotide (FMN) in 26 extended criteria human liver grafts undergoing hypothermic oxygenated perfusion to guide clinical graft assessment. Real-time data identified seven organs unsuitable for transplant that are discarded. The remaining grafts are transplanted and FMN values correlated with post-transplant indicators of liver function and patient recovery. Further, this study shows how this device can be used to monitor dialysis patients by measuring creatinine in real-time. Ourapproach provides a simple method to monitor biomarkers directly within biological fluids to improve organ assessment, patient care, and biomarkerdiscovery.

297 Pressure in the Operating Room (OR): another Possible Contributor to Hospital Acquired Pressure Injuries (HAPIs)

Abstract Introduction Burn patients are at risk for HAPIs. An unexamined factor that may contribute to HAPI development is the effect of pressure from the OR table. Burn patients often require multiple prolonged surgical procedures. The purpose of this study was to measure pressure on the buttocks and sacral area during burn OR procedures under general anesthesia (GA). This has not been previously assessed in the burn literature. Methods Prospective study of consecutive adult burn patients admitted to an ABA-verified burn center who required surgery under GA between 06/01/22 and 08/12/22. We studied only cases that were supine, including those with both legs down (BLD), one leg suspended (one leg up: 1LU) or both legs suspended (two legs up: 2LU). Pressures on the buttocks and sacral area were measured using a commercial sensor mat which sent continuous real-time pressure measurements wirelessly to a laptop computer. Thousands of individual pressure measurements were integrated and organized to show average and peak pressures over repetitive 10-minute intervals during the entire operative procedure. Also, a continuous visual color-coded map of the sacral and buttock areas showing high ( >75 mmHg-red), medium (10-75 mmHg -yellow) and low ( < 10 mmHg -blue/green) pressures was created for each procedure. Results are shown as mean ± SD. Results Recordings were completed in 41 procedures (35 acute excision & grafting, 5 reconstructive, 1 tracheostomy) among 28 patients ( 48 ± 17 yrs, % TBSA burn 19 ± 17, weight 80 ± 20 kg, BMI 27 ± 6). During BLD, over 125 ± 81 min, the average pressure (Pave) was 47 ± 7 mmHg and peak pressure (Ppeak) reached 82 ± 23 mmHg. During isolated 1LU periods, Pave was 53 ± 9 mmHg over 74 ± 58 minutes with a Ppeak of 93 ± 23 mmHg and during isolated 2LU, Pave and Ppeak were respectively 55 ± 10 mmHg over 78 ± 40 min and 98 ± 23 mmHg. Both Pave and Ppeak increased significantly from procedures with BLD to 1LU to 2LU (p< 0.001). Pave crept steadily upwards during both BLD and 1LU or 2LU procedures (Figure). We observed that Pave had a positive relationship with weight, regardless of operative position. Conclusions Prolonged moderate to high pressures are exerted on the sacral and buttock areas, especially with one or both legs suspended, during burn surgery. These novel observations suggest that pressure from the OR table could contribute to HAPI development. Applicability of Research to Practice With this risk identified, interventions to lower or interrupt pressure exposure during burn surgery should be identified next.

Data image correlation analysis of the destruction process of 3D printable layered beams subjected to the 3-point bending process

Technological processes and materials related to Additive Manufacturing (AM) are gaining popularity in civil engineering 3Dconcrete printing is aimed mainly at the process of rising the inner and outer walls of buildings. In these elements, the main load is axial compression with a low fraction of bending. The 3D-printing process of cement-based materials provides the construction elements with appropriate compressive strength. Although creating elements, which can carry the tensile loading is necessary to make the 3D-printing process used in civil engineering. Therefore, this paper aims to show the response of the 3D-printed cement-based composites to the bending process to find the effect of complex layered structures on their effective properties. Instead of the standard use of an extensometer to obtain Crack Mouth Opening Displacement results, novel Digital Image Correlation measurement technology was used during research. This technology allows for continuous real-time measurements that are extremely difficult when testing brittle materials such as concrete and avoids the additional introduction of external forces caused by the classical measuring device. The proposed AM material contains the interlayer polymeric net and smeared polymeric reinforcement to enhance flexural strength. The use of the polymeric net and smeared reinforcement introduces residual strength into the composite allowing for its further work after brittle phase failure. However, the obtained results showed that analysed layered beams had decreased interlayer resistance. The process of layer cracking occurs subsequently layer by layer and the failure in different layers developed as an independent process including cracks arresting.

Fast Spectrum Measurements Using Optical Computing

Traditional spectrometers are too slow for the continuous real-time measurement of rapidly varying spectrum. Dispersive Fourier transformation (DFT) technology replaces diffraction grating and detector array in traditional spectrometers with dispersive elements and photodiodes, and therefore reaches MHz-level spectral capture rate. In addition, frequency-resolved optical gating (FROG) and spectral phase interferometry for direct electric-field reconstruction (SPIDER) are also important ultrafast spectroscopy technologies in relevant fields. However, these approaches have to use mode-locked pulses as probe light, which may cause damages to some samples due to high peak power. Therefore, the requirement for light source restricts the scope of these technologies’ applications. Here, we report a general technique using optical computing for fast spectrum measurements, to overcome the bottleneck of light source in existing ultrafast spectroscopy measurement technologies. The proposed method has no strict requirement on the probe light. It means the common light source could also be applied for fast real-time spectroscopic measurements. In experiments, CW signals with four different optical spectra have been measured at capture speed of 1MHz respectively. The proposed method can overcome the limitations of existing ultrafast spectroscopy technologies in light source, and therefore provide a powerful tool for investigating rapid transient phenomena in many applications.

A study on the Characteristics of HAPs in Residential areas affected by Industrial Complex using SIFT-MS

Objectives:The purpose of this study is to provide basic data so that the emission sources of industrial complexes can be effectively managed through a characteristic study of hazardous air pollutants in residential areas adjacent to the national industrial complex in Ulsan.Methods:In Yaeum-dong, a residential area near the industrial complex, SIFT-MS, which enables real-time continuous measurement, was used to identify the characteristics of VOCs and odorous substances.Results and Discussion:When looking at the concentrations by chemical substance group, aliphatic hydrocarbons accounted for a significant portion, showing different characteristics from other large cities. This indicates that the Yaeum-dong area is directly affected by the emission source of the nearby petrochemical complex. As an individual substance, ammonia showed the highest concentration among HAPs. Seasonal HAPs concentrations generally tended to be high in summer and low in winter. When examining concentrations by time of day, it showed characteristics of industrial areas affected by VOCs scattered and volatilized in national industrial complexes. In addition, it was confirmed that the characteristics of urban areas appearing in general metropolitan traffic congestion zones appeared at the same time. Compared with the results of other previous studies, in general, there was no significant difference in concentrations from the results of measurements in residential areas near petrochemical complexes. And it showed a much lower concentrations than the measured value in industrial complex. As a result of CPF analysis for estimating the source of pollutants, most HAPs showed high concentrations in the south wind direction, indicating that the measurement point was affected by the industrial complex.Conclusion:As a result of the study on the characteristics of HAPs in residential areas near the industrial complex, it can be estimated that both characteristics appear in industrial and urban areas.

Temperature and Humidity Stability of Fibre Optic Sensor Cables for High Resolution Measurements.

Fibre optic sensors offer a means for the real-time continuous measurement of temperature or strain in concrete structures. Backscattered light along a fibre optic sensing (FOS) cable is interrogated to record a frequency shift and this shift is typically translated into a physical parameter such as strain or temperature using a calibration factor. However, when the measured frequency shift is a response to a combination of mechanical, thermal or hygral (humidity) loadings it is difficult to decouple individual influences. This presents a challenge in complex materials such as concrete where the strain, temperature and moisture levels change concurrently during the fresh and hardened states. Furthermore, depending on the application, both short- and longer-term measurements are required. As such, not only is the influence of these physical factors of interest but also the time and spatial stability of the measured frequency, which is highly dependent on the FOS cable composition. To investigate this aspect, fibre optic cables commonly used for strain (three tight-buffered cables) or temperature (two loose-buffered cables) measurement were considered. The cables were subjected to mechanical or environmental exposure and interrogated using a high-resolution optical backscatter reflectometer. The exposure regimes included three temperature cycles with sustained steps from 10 °C to 60 °C and back to 10 °C and an increasing and decreasing humidity cycle with steps between 30 to 90% relH. These ranges were selected to be indicative of typical environments for concrete. The results showed that the calibration factors back-calculated from increasing and decreasing temperature or humidity cycles differed. The third temperature cycle results were found to exhibit the smallest differences between heating and cooling suggesting that temperature pre-conditioning prior to installation could be advantageous. For all the cables, a drift in the readings was observed over the duration (2.5 h for temperature and 30 h for moisture) of the sustained steps. The magnitude of the drift depended on the cable type and exposure condition. In addition, local frequency fluctuations along the cable were observed which would need to be taken into account if only a single point along the cable length was used for analysis. The obtained results highlight the importance of the cable selection to maximise the FOS measurement fidelity for a given parameter of interest.

Incorporating Hydrophobic Moieties into Self-Assembled Monolayers to Enable Electrochemical Aptamer-Based Sensors Deployed Directly in a Complex Matrix.

Continuous real-time measurement of specific targets in complex biological samples is of great significance for early diagnosis and treatment of diseases and thus enables achievement of personalized medicine. Electrochemical aptamer-based (E-AB) sensors are good candidates to fill this role due to their high specificity, sensitivity, rapid detection, and simple preparation. However, this sensor class suffers from severe baseline drift in the complex matrix probably due to the nonspecific adsorption of components. Here, we introduce a series of self-assembled monolayers with a variety of hydrophobic functional groups into an E-AB sensor platform, achieving enhancement of the antifouling performance and thus the detection performance (e.g., stability, sensitivity, and specificity). We reveal that the antifouling performance enhanced by such hydrophobic SAMs is probably due to its instant adsorption of components onto the surface, rather than the repelling of these components by hydrophilic SAMs in previous reports.

Prediction of Electric Power Production and Consumption for the CETATEA Building Using Neural Networks

Economic and social development is hardly influenced by electric power production and consumption. In this context of the energy supply pressure, energy production and consumption must be monitored and controlled in an intelligent way. Due to the availability of large data measurements, prediction algorithms based on neural networks are widely used in accurate power prediction. Firstly, the particularity of our work is represented by the size of the dataset consisting of 4 years of continuous real-time data measurements collected from the CETATEA photovoltaic power plant, a research site for renewable energies located in Cluj-Napoca, Romania. Secondly, the high granularity of the dataset with more than 4.2 million unified production and consumption power values recorded every 30 s guarantees the overall prediction accuracy of the system. Performance metrics used to evaluate the prediction accuracy are the mean bias error, the mean square error, the convergence time of the prediction system, the test performance, and the train mean performance. Test results indicate that the predicted unified electric power production and consumption closely resembles the unified electric power measured values.

Eutrophication Amplifies the Diel Variability of Carbonate Chemistry in an Equatorial, Semi-Arid, and Negative Estuary

This study presents high-resolution data on diel variations of carbonate chemistry in a semi-arid estuary (Jaguaribe River) in NE Brazil, which has witnessed decreasing annual rainfall and freshwater inputs due to climate change and river damming. In addition, the estuary has been suffering with increasing discharges from shrimp farm and urban effluents. We monitored surface water and atmospheric CO2 partial pressure (pCO2), temperature, salinity, and wind speed with continuous real-time measurements during two eulerian surveys in October 2017 (33 h) and September 2018 (44 h), during spring tides in the dry season. Additionally, pH, total alkalinity (TA), dissolved inorganic carbon (DIC), carbonate (CO32–), and saturation state of calcite (Ωcal) and aragonite (Ωara) were monitored hourly. Higher salinity (>38) during ebb tides confirmed the hypersalinity and negative estuarine circulation. TA and DIC concentrations in the estuary were higher than in the adjacent coastal ocean due to evaporation, showing positive correlation with salinity and negative correlation with tidal height. Measured TA and DIC concentrations were slightly higher than those calculated by the conservative evaporation model, suggesting their production in the estuary by aerobic and anaerobic processes. CO32–, Ωcal, and Ωara showed a clear semi-diurnal (tidal-driven) and diel (24 h; biological-driven) patterns: lowest values occurred at flood tide during night-time (respectively, 185 μmol kg–1, 4.3 and 2.8), whereas highest occurred during ebb tide and daytime (respectively, 251 μmol kg–1, 5.7 and 3.8). DIC/TA ratios were higher at night-time supporting a diel control (linked to solar irradiance) of the carbonate buffering capacity. pCO2 was oversaturated comparing to the atmosphere (512–860 μatm) and the estuary was a source of CO2, with fluxes ranging from 2.2 to 200.0 mmol C m–2 d–1 (51.9 ± 26.7 mmol C m–2 d–1), which are higher than emissions normally found in low-inflow, marine-dominated estuaries. The diel variability of DIC indicated a net heterotrophic metabolism averaging −5.17 ± 7.39 mmol C m–2 h–1. Eutrophication amplifies the diel variability of the CO2 system generating large differences between daytime and night-time. The results highlight the importance of considering diel variability when estimating CO2 fluxes and carbonate chemistry in eutrophic, semi-arid, and tidally dominated estuaries under rapid environmental changes, and may represent future conditions in estuaries worldwide experiencing warming, increasing aridity and eutrophication.

Real-time continuous measurement of lactate through a minimally invasive microneedle patch: a phase I clinical study

IntroductionDetermination of blood lactate levels supports decision-making in a range of medical conditions. Invasive blood-sampling and laboratory access are often required, and measurements provide a static profile at each instance....

Fabric-based in situ synthesis of gold nanoparticles for continuous enhanced heterogeneous chemiluminescence online detection of carbon dioxide.

In this paper, nylon microfiber fabric with a heterogeneous chemiluminescence system was used for the synthesis of gold nanoparticles (AuNPs) for the first time, and it was used to enhance the online detection of carbon dioxide (CO2) by heterogeneous chemiluminescence. Nylon microfiber fabric was chosen as the gas-liquid heterogeneous chemiluminescence micro reaction interface. The thermal reduction method prepared the micro reaction interface with in situ synthesized AuNPs. The solution of H2O2 and KOH forms a liquid film on the surface of the micro reaction interface, and a heterogeneous chemiluminescence reaction occurs when CO2 flows through the surface of the liquid film. The AuNPs supported in situ on the micro reaction interface act catalytically and enhance the chemiluminescence signal for CO2 detection. In this way, AuNPs can be used repeatedly in the chemiluminescence reaction, avoiding the waste of precious metal nanoparticles and reducing the detection cost. Under the optimal conditions, CO2 has a good linear relationship with the chemiluminescence signal in the range of 10-20 000 ppm (v/v). The correlation coefficient R2 is 0.9963, the detection limit is 0.35 ppm (v/v), and the relative standard deviation is 1.79%. This approach provides an entirely new technological platform for the development of functional fabrics and the maximum utilization of precious metal nanoparticles.

O-OGC03 Real-time tracking and classification of tumour and non-tumour tissue in upper gastrointestinal cancer specimens using diffuse reflectance spectroscopy

Abstract Background Diffuse reflectance spectroscopy (DRS) is a technique that allows discrimination of normal and abnormal tissue based on spectral data. It is a promising technique for cancer margin assessment. However, application in a clinical setting is limited by the inability of DRS to mark the tissue that has been scanned and its lack of continuous real-time spectral measurements. This aim of this study was to develop a real-time tracking system to enable localisation of the tip of a handheld DRS probe to aid classification of tumour and non-tumour tissue. Methods A coloured marker was attached to the DRS fibre probe and was detected using colour segmentation. A Kalman filter was used to estimate the probe’s tip position during scanning of the tissue specimen. In this way, the system was robust to partial occlusion allowing real-time detection and tracking. Supervised classification algorithms were used for the discrimination between tumour and non-tumour tissue, and evaluated in terms of overall accuracy, sensitivity, specificity, and the area under the curve (AUC). A live augmented view with all the tracked and classified optical biopsy sites were presented, providing visual feedback to the surgeons. Results A green coloured marker was successfully used to track the DRS probe. The measured root mean square error of probe tip tracking was 1.18±0.58mm and 1.05±0.28mm for the X and Y directions, respectively, whilst the maximum measured error was 1.76mm. Overall, 47 distinct sets of tumour and non-tumour tissue data were recorded through real-time tracking of ex vivo oesophageal and gastric tissue. The overall diagnostic accuracy of the system to classify tumour and non-tumour tissue in real-time was 94% for stomach and 96% for the oesophagus. Conclusions We have been able to successfully develop a real-time tracking system for a DRS probe when used on stomach and oesophageal tissue for tumour detection, and the accuracy derived demonstrates the strength and clinical value of the technique. The method allows real-time tracking and classification with short data acquisition time to aid margin assessment in cancer resection surgery.

The US COVID-19 Trends and Impact Survey: Continuous real-time measurement of COVID-19 symptoms, risks, protective behaviors, testing, and vaccination

The US COVID-19 Trends and Impact Survey (CTIS) is a large, cross-sectional, internet-based survey that has operated continuously since April 6, 2020. By inviting a random sample of Facebook active users each day, CTIS collects information about COVID-19 symptoms, risks, mitigating behaviors, mental health, testing, vaccination, and other key priorities. The large scale of the survey-over 20 million responses in its first year of operation-allows tracking of trends over short timescales and allows comparisons at fine demographic and geographic detail. The survey has been repeatedly revised to respond to emerging public health priorities. In this paper, we describe the survey methods and content and give examples of CTIS results that illuminate key patterns and trends and help answer high-priority policy questions relevant to the COVID-19 epidemic and response. These results demonstrate how large online surveys can provide continuous, real-time indicators of important outcomes that are not subject to public health reporting delays and backlogs. The CTIS offers high value as a supplement to official reporting data by supplying essential information about behaviors, attitudes toward policy and preventive measures, economic impacts, and other topics not reported in public health surveillance systems.

A low-cost versatile system for continuous real-time respiratory activity measurement as a tool in environmental research

Low-cost sensors available on the market allow reliable and straightforward research of model organism responses to changes in environmental conditions caused by xenobiotics or natural ecological processes. The purpose of this work was to develop a low-cost Arduino-based respiratory activity measuring system employing CO2 sensors (ResTox) applicable for various research and risk assessment purposes, providing a stable platform and support for further development and extension of current capabilities. The presented system comprises hardware and accompanying software solutions. The instrument employs multiple digital CO2 measuring sensors based on non-dispersive infrared (NDIR) technology, a waterproof temperature sensor, and a phototransistor light sensor. The cross-platform ResTox software support enables simple control of the measuring device and sensor output data storage during the experiments. Due to its uncomplicated and compact design, the developed system represents a versatile solution for experiments in both field and laboratory conditions and with animal and plant organisms.

Design of a solid scintillation counter for tritium water measurement based on Ca2F(Eu) sheet using Monte Carlo simulation

To measure the tritium concentration in water with an environmentally friendly way, a new detection method based on CaF2(Eu) sheet is being developed. The design of the detector is important in this method, and each basic unit of the detector consists of a pair of CaF2(Eu) sheets and a sample chamber for holding tritium water. The detector is coated with aluminum foil to avoid light and reflect scintillation photons which are received by a pair of photomultiplier tubes on both ends. The physical process of tritium water concentration detection was simulated by Monte Carlo simulation using the Geant4 tool kit. The energy deposition results in scintillator of electrons produced by tritium decay and the absorption probability of scintillation photons in sample chamber and scintillator were obtained in the simulation. The simulation results indicated that the thickness of the sample chamber had a major influence on detection efficiency, while the photon collection efficiency mainly depended on the thickness of the CaF2(Eu) sheet. The design of solid scintillation counter with multiple sample chambers can effectively improve the counting rate of the detection system. According to the simulation results, three types of detectors are designed, which have the characteristics of high detection efficiency, high counting rate and continuous real-time measurement capability respectively. Of the three types of detectors, type 2 detector has the lowest detection limit: 7.46 Bq/mL at a counting time of 10 min, and 2.95 Bq/mL at a counting time of 60 min.