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• Combining multistage thermoelectric cooler with infrared detectors for analysis. • Finite rate heat transfer irreversibility is considered and a finite time thermodynamic model of a heat-pipe-type four-stage thermoelectric cooler is developed. • New evaluation indexes are proposed: module utilization coefficient and coordination performance coefficient. • Heat pipe is used to enhance heat transfer and improve the performance of the thermoelectric cooler. • Large temperature difference cooling to meet the requirements of detectors is achieved. A cooler provides a low-temperature working environment for refrigerated infrared detection chips and is an indispensable component in infrared detectors that ensures their smooth operation. In this paper, a thermodynamic model of a heat-pipe-type four-stage thermoelectric cooler with a large temperature difference applied to a focal plane infrared detector is constructed. The heat leakage of the detector is calculated using the model. The performance indexes of the coordination performance coefficient and module utilization coefficient are used to unify the cooling capacity and economic performance of the device. The impression of the working current, heat pipe parameters, and cross-sectional area of the thermoelectric leg on the performance of cooler are analyzed. A Pareto optimal solution is obtained using an NSGA-II algorithm and TOPSIS decision. A low cooling temperature is obtained using a multistage thermoelectric cooler to achieve a large cooling temperature difference. When the working current is 5.65 A and the cross-sectional area is 4.5 mm2, the maximum cooling temperature difference reaches 110.6 °C, and the lowest cooling temperature reaches -83.6 °C. When the working temperature of the detector is -60 °C, the current and cross-sectional area corresponding to the optimal solution of cooling capacity-COP-power consumption are 1.51 A and 2.74 mm2, respectively. [ABSTRACT FROM AUTHOR]

This paper presents a hermitic fiber sensor packaging technique that enables fiber sensors to be embedded in energy systems for performing multi-parameter measurements in high-temperature and strong radiation environments. A high-temperature stable Intrinsic Fabry–Perot interferometer (IFPI) array, inscribed by a femtosecond laser direct writing scheme, is used to measure both temperature and pressure induced strain changes. To address the large disparity in thermo-expansion coefficients (TECs) between silica fibers and metal parts, glass sealants with TEC between silica optical fibers and metals were used to hermetically seal optical fiber sensors inside stainless steel metal tubes. The hermetically sealed package is validated for helium leakages between 1 MPa and 10 MPa using a helium leak detector. An IFPI sensor embedded in glass sealant was used to measure pressure. The paper demonstrates an effective technique to deploy fiber sensors to perform multi-parameter measurements in a wide range of energy systems that utilize high temperatures and strong radiation environments to achieve efficient energy production. [ABSTRACT FROM AUTHOR]

The article discusses the need for a standardized circuit diagram for continuous renal replacement therapy (CRRT). The authors argue that a homogenized set of CRRT model diagrams, similar to a circuit diagram, is necessary to help users understand the basic principles and operating characteristics of different CRRT techniques. The article describes the design process for creating these diagrams, which include icons, symbols, lines, and letters to illustrate the working principles of various CRRT modalities. The authors believe that these standardized diagrams will facilitate teaching, training, and academic communication in the field of CRRT. [Extracted from the article]

Hydrogen (H2) is positioned as a key solution to the decarbonization challenge in both the energy and transportation sectors. While hydrogen is a clean and versatile energy carrier, it poses significant safety risks due to its wide flammability range and high detonation potential. Hydrogen leaks can occur throughout the hydrogen value chain, including production, storage, transportation, and utilization. Thus, effective leak detection systems are essential for the safe handling, storage, and transportation of hydrogen. This review aims to survey relevant codes and standards governing hydrogen-leak detection and evaluate various sensing technologies based on their working principles and effectiveness. Our analysis highlights the strengths and limitations of the current detection technologies, emphasizing the challenges in achieving sensitive and specific hydrogen detection. The results of this review provide critical insights into the existing technologies and regulatory frameworks, informing future advancements in hydrogen safety protocols. [ABSTRACT FROM AUTHOR]

For the sake of realizing the safety detection of natural gas and petroleum pipeline welds, this paper designs a ferromagnetic pipeline weld magnetic flux leakage detector based on the calculation of the magnetic circuit of the detection probe, with the magnetization direction perpendicular to the traveling direction. The traditional pipeline magnetic flux leakage detection device uses a detection system mode in which the magnetization direction is parallel to the direction of travel. However, due to the structural characteristics of the weld, the traditional detection system mode is not applicable. Since the weld magnetic flux leakage detector needs to travel along the direction of the weld, the detector designed in this paper rotates the magnetizer 90 degrees along the direction of the weld seam so that the magnetization direction is perpendicular to the direction of travel, breaking through the technical barrier that make traditional magnetic flux leakage detection devices unsuitable for weld detection. The detection device includes a magnetizing structure, a data sampling device, and a driving and traveling device. The magnetic flux leakage signal collected by the detector is converted into a digital image in the form of a grayscale matrix. Using mathematical morphology and chain code algorithms in image processing technology, a pipeline weld defect inversion software system is developed, and a preliminary quantitative analysis of pipeline weld defects is achieved. The application of this technology enables the inspection and protection of oil and gas pipeline welds throughout their life cycle, broadens the scope of existing inspection objects, and is of great safety significance for ensuring national public security. [ABSTRACT FROM AUTHOR]

The introduction of hydrogen into the gas grid requires stricter safety measures due to its enhanced flammability compared to natural gas. Detecting small hydrogen leaks is crucial for meeting health and safety requirements, given hydrogen's potential for easy ignition and the hazards associated with its combustion. This paper presents an overview of the quantification of small hydrogen leaks, regarding conversions between common units of measurement, namely concentration and leak rate. In addition, the need for traceable assessments of hydrogen leakage was also considered, which included proposal of the design, calibration, and metrological evaluation of portable hydrogen reference leaks in the range of 10−6 to 10−4 Std cm3/s, the latter being considered as the lowest side of the range of interest for quantifying hydrogen leaks. Two methods of manufacturing leak artefacts, namely conductance and permeation, are explored, and the produced leaks were used to test two hydrogen leak detectors with different working principles. A calibration technique based on a constant pressure gas flowmeter is described together with the uncertainty budget. The study provides insights into the challenges of calibrating detectors for hydrogen leaks, highlighting the importance of traceability in ensuring safety and environmental protection in the context of hydrogen infrastructure. It was demonstrated that reference leaks are highly suitable to test hydrogen leak detectors in the mentioned flow range due to their simplicity, high reliability, low depletion rate and high portability. • Traceability of small hydrogen leaks is challenging. • Reference leaks allow quantitative testing of hydrogen leak detectors. • Designs for the construction of hydrogen reference leaks are disclosed. • Hydrogen reference leaks can be calibrated by a constant pressure gas flowmeter. • Linearity and reproducibility of hydrogen leak detector was assessed. [ABSTRACT FROM AUTHOR]

The article is devoted to the study of a methane leak detector based on absorption spectroscopy. An LED matrix with a wavelength of ~3.3 μm was used as a radiation source, where one of the methane absorption lines is located. The system is temperature stabilized. A threshold sensitivity of approximately 60 ppm CH4 was obtained. [ABSTRACT FROM AUTHOR]

A novel floating-electrode silicon pixel detector has been proposed. The novel configuration of the floating electrode in the silicon pixel detector reduces the size of the collecting cathode and decreases both the capacitance and leakage current of the detector compared to the conventional silicon pixel detector. For the design, we used a 200 × 200 µm2 detector as the model to analyze the impact of varying numbers of floating rings on the electrical performance [Wu et al., AIP Adv. 11(2), 025315 (2021)]. We used Technology Computer Aided Design simulation to compare and analyze the simulated electric field, potential, capacitance, and breakdown voltage of the detector. The results show that decreasing the gap-to-width ratio of the floating electrode, as well as increasing the quantity of floating rings, enhances the detector's performance. [ABSTRACT FROM AUTHOR]

Insurers are incentivizing customers to use smart home technology, such as smart leak detectors, to mitigate risk and prevent claims. By providing accurate information to claims teams, smart home technology can fast-track the claims process and even prevent claims altogether. Some insurers are offering discounts on premiums or providing smart leak detectors to policyholders for free. However, the uptake of smart leak detectors is still low, and insurers must address concerns around cybersecurity and data privacy. Despite challenges, there is a growing appetite for smart home technology, and insurers can benefit from reduced risks, enhanced customer engagement, and differentiation in the market. [Extracted from the article]

The sample tubes on board NASA's Perseverance rover are designed to contain rocks, regolith, and atmospheric gases and are hermetically sealed on the surface of Mars to minimize sample loss, alteration, and contamination. Following a robust testing program during mission development, it was determined that the helium (He) leak rates of flight-like sample tubes sealed under a range of conditions were typically no greater than ∼10−10 standard cubic centimeters per second (scc/s); leak rates below this value could not be measured since this is the detection limit of commercially available He leak detectors. This limit was adequate to meet mission requirements. However, some scientific objectives could be compromised by sample tube leak rates even below 10−10 scc/s, thus motivating a more sensitive technique for establishing leak rates. This study investigated He leak rates on six flight-like sample tubes using a static mode mass spectrometer. Room temperature He leak rates of the six sample tubes ranged from ∼8.8 × 10−17 to ∼4.6 × 10−14 scc/s. One sample tube was analyzed at eight different temperatures, ranging from -51°C to +42°C, and yielded He leak rates correlated with temperature that varied from ∼1.7 × 10−15 to ∼1.4 × 10−13 scc/s, respectively. Our results confirm and extend previous findings demonstrating that the Mars 2020 sample tube seals are likely to be very leak-tight, with leak rates <10−13 scc/s. These leak rates are sufficiently low that the impact of gas egress or ingress is expected to be negligible. [ABSTRACT FROM AUTHOR]

Hydrogen has the potential to promote sustainable road transport in the forthcoming years, thus significantly reducing the human impact on the environment. This energy carrier can be produced by renewable energy through water electrolysis and used in fuel cell-powered vehicles (FCVs) with elevated efficiency and no pollutant emissions. The number of FCVs being used around the world is rapidly increasing, reaching 34,804 vehicles and 540 refueling stations by the end of 2020. Nevertheless, hydrogen is highly flammable and can permeate and embrittle most metallic materials, making its containment extremely challenging. A leak in a hydrogen refueling station can rapidly escalate to a major disaster if not promptly detected and addressed. In this perspective, gas sensors play a critical role in detecting leakages and undesired hydrogen releases. When selecting a hydrogen gas detector, it is important to consider the environmental conditions in which it is expected to operate, its performance, reliability, and cost, as well as the optimal positioning within the refueling station. This study analyzes several hydrogen releases from a high-pressure storage tank to optimize sensor positioning, given a certain detection probability. This research contributes towards advancing the modelling of safety barriers in hydrogen refueling stations considering accident scenarios. In this vein, this study aims at expanding the current knowledge of facility operators and stakeholders for related risks, thus enabling the widespread utilization of hydrogen in road transport. [ABSTRACT FROM AUTHOR]

Power-based Side-Channel Analysis (SCA) began with visual-based examinations and has progressed to utilize data-driven statistical analysis. Two distinct classifications of these methods have emerged over the years; those focused on leakage exploitation and those dedicated to leakage detection. This work primarily focuses on a leakage detection-based schema that utilizes Welch's t-test, known as Test Vector Leakage Assessment (TVLA). Both classes of methods process collected data using statistical frameworks that result in the successful exfiltration of information via SCA. Often, statistical testing used during analysis requires the assumption that collected power consumption data originates from a normal distribution. To date, this assumption has remained largely uncontested. This work seeks to demonstrate that while past studies have assumed the normality of collected power traces, this assumption should be properly evaluated. In order to evaluate this assumption, an implementation of Tiny-AES-c with nine unique substitution-box (s-box) configurations is conducted using TVLA to guide experimental design. By leveraging the complexity of the AES algorithm, a sufficiently diverse and complex dataset was developed. Under this dataset, statistical tests for normality such as the Shapiro-Wilk test and the Kolmogorov-Smirnov test provide significant evidence to reject the null hypothesis that the power consumption data is normally distributed. To address this observation, existing non-parametric equivalents such as the Wilcoxon Signed-Rank Test and the Kruskal-Wallis Test are discussed in relation to currently used parametric tests such as Welch's t-test. [ABSTRACT FROM AUTHOR]

The article offers reviews on a several products in fluids and solids handling: DENIOS' FALCON full-size funnel for efficient IBC totes refilling, Kaeser Compressors' i.Comp 8 and 9 oilless air compressors for high-performance applications.

Ensuring early leak detection and implementing effective secondary containment systems are critical for preventing the dispersion of hazardous liquids and minimizing the casualties of a chemical accident. This study reviews the standards for leak detectors and their placement in various regions, as well as the key parameters involved in bund design such as bund capacity, bund wall height, and separation distance from the bund wall. In this study, Computational Fluid Dynamics (CFD) simulations are conducted considering storage tanks with heights (H) of 1.75 m, 3.5 m, and 7.0 m. The detection times using a level transmitter (LT) and a leak sensor are compared at eight monitoring points. Exclusively employing the leak sensor led to a significant detection time delay of up to 16 times, ranging from 0.5 s to 8.1 s depending on the placement of the leak sensors. However, the average rate of liquid level change was 3.0 mm/s, which demonstrates that the LT consistently detects leaks faster than the leak sensor at all monitoring points. Hence, the integration of an LT alongside a leak detector offers a valuable approach to expedite leak detection, regardless of the direction or location of the leak. Furthermore, the optimized separation distance between the storage tank and the bund wall is suggested. The analytical solution and numerical solution for a separation distance matches up to 95% for H = 1.75 m. The separation distance increases as both the tank height and the height of the leak source increase. The relationship between the separation distance and the tank height exhibits a square root dependence on the liquid level from the leak point. The proposed detection method and optimized separation distance hold the potential to facilitate a revision of liquid storage and handling standards grounded in robust scientific and quantitative evidence. [ABSTRACT FROM AUTHOR]

Silicon membrane strip photodetectors are fabricated based on thin silicon-on-insulator (SOI) wafers. The thin SOI wafer is realized by exploiting a thinning process on backside. Such detectors can be implemented in proton-beam position detection because its ultra-thin membrane substrate can reduce beam scattering and offer the considerable advantages of higher radiation hardness. A p-spray implantation process is typically performed at the silicon surface between the n + -strips in order to insulate them, without requiring an extra photolithographic mask. In this paper, the sources of leakage current in the detector are first studied by considering both activation energy and simulation analysis in Silvaco TCAD. While the device is operating below avalanche breakdown voltage, the Shockley–Read–Hall process and trap-assisted-tunneling process are dominantly contributing to leakage current. The dominant breakdown voltage is attributed to the premature breakdown in the junction of p − spray / n + region. The shift of this breakdown voltage under repeated avalanche processes is analyzed in-depth by both experiments and simulations, as a function of temperature and electrical stress conditions, which are introducing an important reliability problem. The electrical stress can be attributed to an increase in fixed charge density at the Si/ SiO 2 interface. The breakdown voltage finally increases by 4 V after successive avalanche breakdowns as a function of the applied excess bias voltage beyond breakdown voltage. [ABSTRACT FROM AUTHOR]

Water is an invaluable resource quickly becoming scarce in many parts of the world. Therefore, the importance of efficiency in water supply and distribution has greatly increased. Some of the main tools for limiting losses in supply and distribution networks are leakage sensors that enable real-time monitoring. With fiber optics recently becoming a commodity, along with the sound advances in computing power and its miniaturization, multipurpose sensors relying on these technologies have gradually become common. In this study, we explore the development and testing of a multimode optic-fiber-based pipe monitoring and leakage detector based on statistical and machine learning analyses of speckle patterns captured from the fiber's outlet by a defocused camera. The sensor was placed inside or over a PVC pipe with covered and exposed core configurations, while 2 to 8 mm diameter pipe leaks were simulated under varied water flow and pressure. We found an overall leak size determination accuracy of 75.8% for a 400 µm covered fiber and of 68.3% for a 400 µm exposed fiber and demonstrated that our sensor detected pipe bursts, outside interventions, and shocks. This result was consistent for the sensors fixed inside and outside the pipe with both covered and exposed fibers. [ABSTRACT FROM AUTHOR]

Natural gas (NG) leaks from below-ground pipelines pose safety, economic, and environmental hazards. Despite walking surveys using handheld methane (CH4) detectors to locate leaks, accurately triaging the severity of a leak remains challenging. It is currently unclear whether CH4 detectors used in walking surveys could be used to identify large leaks that require an immediate response. To explore this, we used above-ground downwind CH4 concentration measurements made during controlled emission experiments over a range of environmental conditions. These data were then used as the input to a novel modeling framework, the ESCAPE−1 model, to estimate the below-ground leak rates. Using 10-minute averaged CH4 mixing/meteorological data and filtering out wind speed < 2 m s−1/unstable atmospheric data, the ESCAPE−1 model estimates small leaks (0.2 kg CH4 h−1) and medium leaks (0.8 kg CH4 h−1) with a bias of −85%/+100% and −50%/+64%, respectively. Longer averaging (≥3 h) results in a 55% overestimation for small leaks and a 6% underestimation for medium leaks. These results suggest that as the wind speed increases or the atmosphere becomes more stable, the accuracy and precision of the leak rate calculated by the ESCAPE−1 model decrease. With an uncertainty of ±55%, our results show that CH4 mixing ratios measured using industry-standard detectors could be used to prioritize leak repairs. [ABSTRACT FROM AUTHOR]

The article provides reviews of various safety products and equipment for environmental and health purposes, including the "spill containment sumps" from DENIOS, the "heavy-duty gloves" from Klein Tools, and the "safety helmet" from Pyramex.

Commercial refrigeration systems currently utilize refrigerants with global warming potential (GWP) values ranging from 1250 to 4000. The advent of low GWP alternatives (GWP < 150 ) is expected to significantly curtail direct emissions from this segment and greatly influence the ongoing electrification and decarbonization efforts. Most of the low GWP alternatives exhibit flammability risk and hence require robust sensing solutions for a reliable and safe operation of the equipment. This review article aims to provide an overview of different sensing mechanisms suitable for potential applications in systems employing flammable refrigerants, particularly those designated as A2L class. A summary of different A2L refrigerants and their properties is provided followed by a broad review of different classes of sensors, their working principle, transduction method, features, advantages, and limitations. Additionally, key performance characteristics of accuracy, selectivity, sensitivity, dynamic characteristic, and durability among other properties are discussed. Finally, areas of improvement and corresponding approaches are suggested for potential sensors in the successful adoption of A2L class refrigerants. [ABSTRACT FROM AUTHOR]

In some countries with high population densities including Korea, chemical plants are densely distributed, and strict regulations are imposed. According to the Chemical Control Act, one gas detector must be installed every 10 m indoors and 20 m outdoors around a facility. However, the diffusion of chemicals should be evaluated based on area rather than perimeter. In the US and EU, gas detector locations are selected through chemical accident modeling. Here, we evaluated the feasibility of gas detector installation standards in the Chemicals Control Act by comparing highly volatile and toxic chemicals with sulfuric acid (relatively low volatility). Consequently, we suggested an appropriate installation location and number of gas detectors for initial countermeasures. For nitric acid, hydrochloric acid, and hydrofluoric acid, there was a difference in the number of detectors recommended via modeling and the number of detectors legally required. For the mezzanine design, four gas detectors should be installed on each floor in a 5‐story building; however, the modeling results showed that installing one was sufficient. For sulfuric acid with low vapor pressure, it is equitable to install a leak detector rather than a gas detector. Overall, regulations should be continuously evaluated for the response and prevention of chemical accidents. [ABSTRACT FROM AUTHOR]

Background: Fluorescence quenching is an interesting phenomenon with the potential to be applied across various fields. The mechanism is commonly used across analytical applications for monitoring the concentration of trace substances. Naphthalimide and its family of compounds are commonly used as fluorescent detectors. This work investigated an analytical technique through which naphthalimide-based dyes could be quantified. A commercial A/C leak detector was used as the dye and Cu2+ ions as the quencher. Experiments were also conducted to investigate the effect of temperature on quenching. To study the mechanism of quenching further, density functional theory (DFT) was used. Results: The method detection limit obtained in this work is 1.7 × 10–6 mol/L. The results from the quenching experiments demonstrated a pattern which fit a modified Stern–Volmer (SV) model, with an R2 value of 0.9886. From the experiments on the effect of temperature, a dynamic quenching behavior was observed given the emission spectra demonstrated an inverse relationship with temperature. Conclusions: The quenching of the commercial A/C dye by Cu2+ ions can be used to develop a rapid and sensitive detection method for metal ions such as Cu2+, and for future fabrication of chemosensors for Cu2+. [ABSTRACT FROM AUTHOR]

• Used off-the-shelf components to build an ultrasonic leak detector. • Conducted experiments to identify response of detector to simulated leaks in wall AC unit. • Depending upon sensor and leak location, detector responds to maximum safe leak rate. • Environmental ultrasonic noise is unlikely to interfere with detector. There is a growing need for cost-effective leak detection in smaller RACHP equipment that uses R290 and other flammable hydrocarbon refrigerants. Gas detection technology may not be suitable in many cases due to cost and reliability implications whilst detection with system parameters can suffer long response times. Ultrasonic leak detection can be an economical and reliable method. This study presents the development and testing of an ultrasonic leak detector using off-the-shelf components, within a conventional split type wall-mounted air conditioner indoor unit. Depending upon the chosen sensor, a fast and effective response to simulated "small" R290 leaks was achieved. Measurements of potential interference from environmental noise across ultrasonic frequencies suggests false alarms are unlikely. Such a leak detector was found to be potentially effective. [ABSTRACT FROM AUTHOR]

Some electrical tape keeps the fishing line sling in place (in a production-related groove). gl As the Pocket Dipper and the LED bait solution are relatively new, their popularity is hard to evaluate, but the classic plopper and the well whistle are commercially available and apparently still in use (the latter especially in German-speaking countries). "Groundwater: Making the invisible visible" is the theme of the World Water Day 2022 and the title of the corresponding UN World Water Development Report (United Nations [8]). Making the Invisible Audible: A Simple Sound-Emitting Water Level Meter Repurposing an Off-the-Shelf Water Leak Sensor Commercially available water leak sensors, attached to a measuring tape, may offer a convenient low-threshold way to improvise a low-cost water level meter - without deciphering circuit diagrams and firing up a soldering iron. [Extracted from the article]

Electrical power is essential in human life. Thus, the security and reliability of its supply are of critical importance in a country's industrial and economic development. The leakage and improper use of electricity may cause serious problems such as fire and electrocution. To prevent such incidents and minimize the loss of life and property, a leakage current detector and warning system are developed in this study. With a high-precision current transformer and high-gain linear converter, the detector effectively detects leakage current over 1 mA, which is validated in different methods. The detector can be integrated into widely used electric meters (Taipower Datong's sub-meter model D4S) easily, and information on detected leakage current is transmitted to the cloud server through narrowband IoT wireless communication (NB-IoT) to warn users and management personnel of the electrical power line. The proposed detector and system are expected to prevent the fire caused by leakage current which was the main cause of the fire at homes and buildings and can be an effective means to manage the electrical powerline system and metering facilities. [ABSTRACT FROM AUTHOR]

This paper is concerned with the design of a Charge Sensitive Amplifier (CSA) in a 28 nm CMOS technology. The CSA discussed in this work is conceived for High Energy Physics (HEP) experiments at next-generation colliders, where pixel detectors will be read out by specific front-end chips, typically including a CSA exploited for charge-to-voltage conversion of the signal delivered by the sensor. The main analog performance parameters of the CSA, also referred to as the pre-amplifier, are assessed here by means of specific Spectre simulations, which are meant to evaluate the behavior of the analog processor in terms of noise, linearity and capability to compensate for very large detector leakage currents. Noise simulations revealed an equivalent noise charge close to 75 electrons rms for typical operating conditions. Up to 50 nA sensor leakage current can be compensated for thanks to the CSA Keummenacher feedback network. The total current consumption of the CSA is close to 2.2 µA, which, together with a power supply of 0.9 V, translates to a power consumption of 2.0 µW. [ABSTRACT FROM AUTHOR]

Tritium extraction is one of the key open issues toward the development of the WCLL BB (Water-Cooled Lithium–Lead Breeding Blanket) of EU DEMO reactors, and different technologies have been proposed to address it. Among them, the Permeator Against Vacuum (PAV) has promising features, but it has never been tested in a relevant environment. This work presents the first experimental results ever obtained for a PAV mock-up. The experiments were carried out at ENEA Brasimone R.C. with the TRIEX-II facility on a mock-up characterized by a shell and tube configuration and using niobium as a membrane material. The experimental campaign was carried out with LiPb flowing at about 450 °C and 1.2 kg/s, while the hydrogen partial pressure was varied in the range 170–360 Pa. The characterization of the PAV performance was conducted by measuring the hydrogen partial pressure drop across the mock-up and the hydrogen permeated flux through a leak detector calibrated with an external hydrogen calibration cylinder. Moreover, the permeated flux was confirmed by a pressurization test performed measuring the pressure increase on the vacuum side of the PAV. The results constitute the first verification of the possibility to operate a PAV in flowing LiPb and to quantify its capabilities. [ABSTRACT FROM AUTHOR]

The conversion of hazardous bio-resources into valuable carbon materials is instrumental in sustainable material manufacturing and green electronics. The present work discourses the transformation of an invasive alien plant species (IAPS), Prosopis juliflora leaves, into a valuable biomass carbon. The characteristics and implications of Prosopis juliflora biomass carbon (PJBMC) are studied in detail. Further, biomass carbon nanocomposites are prepared by decorating SnO2 nanoparticles on the PJBMC, and it is evaluated for hazardous NO2 gas sensing applications. The PJBMC/SnO2 nanocomposite is assessed against varying concentrations of NO2 gas and shows a maximum sensitivity of 31.0 ± 0.9% for 90 ppm of the target gas. The uniform distribution of SnO2 nanoparticles on the biomass carbon support enabled the adsorption/desorption of target gas on the surface of the nanocomposite. The gas sensing mechanism of biomass nanocomposite material is discussed in detail, and a real-time NO2 gas leak detector with a warning LED system is demonstrated. In summary, this work reinforces sustainable growth by reporting the conversion and usage of IAPS Prosopis juliflora as one of the potential carbon materials in sensing applications. [ABSTRACT FROM AUTHOR]

Adopting proton exchange membrane fuel cells fuelled by hydrogen presents a promising solution for the shipping industry's deep decarbonisation. However, the potential safety risks associated with hydrogen leakage pose a significant challenge to the development of hydrogen-powered ships. This study examines the safe design principles and leakage risks of the hydrogen gas supply system of China's first newbuilt hydrogen-powered ship. This study utilises the computational fluid dynamics tool FLACS to analyse the hydrogen dispersion behaviour and concentration distributions in the hydrogen fuel cell room based on the ship's parameters. This study predicts the flammable gas cloud and time points when gas monitoring points first reach the hydrogen volume concentrations of 0.8% and 1.6% in various leakage scenarios, including four different diameters (1, 3, 5, and 10 mm) and five different directions. This study's findings indicate that smaller hydrogen pipeline diameters contribute to increased hydrogen safety. Specifically, in the hydrogen fuel cell room, a single-point leakage in a hydrogen pipeline with an inner diameter not exceeding 3 mm eliminates the possibility of flammable gas cloud explosions. Following a 10 mm leakage diameter, the hydrogen concentration in nearly all room positions reaches 4.0% within 6 s of leakage. While the leakage diameter does not impact the location of the monitoring point that first activates the hydrogen leak alarm and triggers an emergency hydrogen supply shutdown, the presence of obstructions near hydrogen detectors and the leakage direction can affect it. These insights provide guidance on the optimal locations for hydrogen detectors in the fuel cell room and the pipeline diameters on hydrogen gas supply systems, which can facilitate the safe design of hydrogen-powered ships. [ABSTRACT FROM AUTHOR]

In predicting the leakage point of a strip-type chemical sensor used in large-scale chemical plants, the leakage point can be predicted by measuring the input capacitance of the sensor strip, but the position prediction accuracy is poor. In this study, it is demonstrated that the accuracy of predicting leakage points can be improved by modeling the sensor strip as a lossy transmission line. [ABSTRACT FROM AUTHOR]

The dark leakage current of AlxGa1-xN Schottky barrier detectors with different Al contents is investigated. It was found that the dark leakage of AlxGa1-xN detectors increased with increasing Al content. The XRD and SIMS results showed that there was no significant difference of the dislocation density and carbon impurity concentration in five AlxGa1-xN samples with different Al content. This was likely not the main reason for the difference in dark leakage current of AlxGa1-xN detectors. However, the results of positron annihilation showed that the vacancy defect concentration increased with increasing Al content. This was consistent with the result that the dark leakage current increased with increasing Al content. With the increase of vacancy concentration, the vacancy defect energy levels also increased, and the probability of electron tunneling through defect levels increased. In contrast, the Schottky barrier height decreased, which eventually led to the increase of dark leakage current. This discovery should be beneficial to an accurate control of the performance of AlxGa1-xN detectors. [ABSTRACT FROM AUTHOR]

Development of a robust, thin, hole-blocking (n+) contact on high purity germanium (HPGe) has been the main challenge in the development of Ge-based radiation sensors. Yttrium has been reported to be a viable hole-blocking contact on HPGe, and detectors with low leakage have been fabricated. Niobium has also been considered as a potential hole-blocking contact due to its low work function. Here, we investigate interface chemistry and the Schottky barrier height of Y and Nb, as well as electron-blocking contacts Au and Pt, on Ge(100) surfaces using hard x-ray photoelectron spectroscopy. We find a barrier height of 1.05 ± 0.10 eV for Y/HPGe, confirming the formation of a hole-blocking barrier. For Nb/HPGe, the barrier height of 0.13 ± 0.10 eV demonstrates that the interface is not hole-blocking. The Schottky barrier of Au and Pt was found to be 0.45 ± 0.10 and 0.51 ± 0.10 eV, respectively. [ABSTRACT FROM AUTHOR]

Traditional gas pipeline leak detection methods require task offload decisions in the cloud, which has low real time performance. The emergence of edge computing provides a solution by enabling offload decisions directly at the edge server, improving real-time performance; however, energy is the new bottleneck. Therefore, focusing on the gas transmission pipeline leakage detection scenario in real time, a novel detection algorithm that combines the benefits of both the heuristic algorithm and the advantage actor critic (AAC) algorithm is proposed in this paper. It aims at optimization with the goal of real-time guarantee of pipeline mapping analysis tasks and maximizing the survival time of portable gas leak detectors. Since the computing power of portable detection devices is limited, as they are powered by batteries, the main problem to be solved in this study is how to take into account the node energy overhead while guaranteeing the system performance requirements. By introducing the idea of edge computing and taking the mapping relationship between resource occupation and energy consumption as the starting point, the optimization model is established, with the goal to optimize the total system cost (TSC). This is composed of the node's transmission energy consumption, local computing energy consumption, and residual electricity weight. In order to minimize TSC, the algorithm uses the AAC network to make task scheduling decisions and judge whether tasks need to be offloaded, and uses heuristic strategies and the Cauchy–Buniakowsky–Schwarz inequality to determine the allocation of communication resources. The experiments show that the proposed algorithm in this paper can meet the real-time requirements of the detector, and achieve lower energy consumption. The proposed algorithm saves approximately 56% of the system energy compared to the Deep Q Network (DQN) algorithm. Compared with the artificial gorilla troops Optimizer (GTO), the black widow optimization algorithm (BWOA), the exploration-enhanced grey wolf optimizer (EEGWO), the African vultures optimization algorithm (AVOA), and the driving training-based optimization (DTBO), it saves 21%, 38%, 30%, 31%, and 44% of energy consumption, respectively. Compared to the fully local computing and fully offloading algorithms, it saves 50% and 30%, respectively. Meanwhile, the task completion rate of this algorithm reaches 96.3%, which is the best real-time performance among these algorithms. [ABSTRACT FROM AUTHOR]

Planar ortho-mode transducers (OMTs) are a commonly used method of coupling optical signals between waveguides and on-chip circuitry and detectors. While the ideal OMT–waveguide coupling requires minimal disturbance to the waveguide, when used for mm-wave applications the waveguide is typically constructed from two sections to allow the OMT probes to be inserted into the waveguide. This break in the waveguide is a source of signal leakage and can lead to loss of performance and increased experimental systematic errors. Here, we report on the development of new OMT-to-waveguide coupling structures with the goal of reducing leakage at the detector wafer interface. The pixel-to-pixel optical leakage due to the gap between the coupling waveguide and the backshort is reduced by means of a protrusion that passes through the OMT membrane and electrically connects the two waveguide sections on either side of the wafer. High-frequency electromagnetic simulations indicate that these protrusions are an effective method to reduce optical leakage in the gap by ∼ 80 % percent, with a ∼ 60 % filling factor, relative to an standard OMT coupling architecture. Prototype devices have been designed to characterize the performance of the new design using a relative measurement with varying filling factors. We outline the simulation setup and results and present a chip layout and sample box that will be used to perform the initial measurements. [ABSTRACT FROM AUTHOR]

• Fiber sensor based on Michelson interferometric to achieve a leak signals detector in the pipeline. • Field experiments were conducted in gas valve chambers, to analyze the characteristics of leak signals in the pipeline. • The detection of the leak signals in far end depends on the propagation of the infrasound in pipeline. The advantages of fiber optic sensors based on fiber optic interferometers with explosion-proof safety in gas pipeline monitoring has gradually emerged. A monitoring system for natural gas pipelines was designed and implemented using a Michelson interferometer as the core structure of the fiber optic sensor and processed the collected data using phase carrier generation demodulation algorithms. Addressing practical issues such as phase wrapping and arm length difference losses, an improved phase carrier demodulation algorithm based on tangent transformation and arctangent-differential self-cross-multiplication was proposed. Field experiments were conducted in gas valve chambers, to analyze the characteristics of leak signals in the pipeline. This study lays the foundation for the application of fiber optic interferometer sensors in gas pipeline monitoring, promising enhanced safety and efficiency. [ABSTRACT FROM AUTHOR]

In this proposed work, water leakage detection in Polyvinyl chloride (PVC) pipes has been investigated using a ring filter connected to log-periodic feedlines (LPF). The proposed filter has a well-structured ring design to adjust the PVC pipes and operates between 0.3 GHz & 0.7 GHz. Using a signal generator & analyzer, attenuation measurements are obtained to analyze the impact of water leakage. PVC pipes with varying diameters (3 inches, 2 inches, 1.5 inches, & 1 inch) are connected with water stoppers to control the water flow during experiments. The leak is contained within a plastic tub to make measurements easier. Results show a good connection between attenuation & water level for all pipe diameters, supporting the LPF-based ring filter's effectiveness as a leakage detector. An analogous circuit model is created to evaluate the filter's performance further. At the same time, the resonant parameters, such as Q-factors & resonant frequencies, are retrieved from S 21 magnitude measurements in the operating frequency range. The proposed methodology is shown to be accurate & reliable, offering significant potential for water leakage detection in PVC pipe systems. By accurately detecting water leakage, this technology enables prompt repairs, reducing water loss & associated costs, enhancing water infrastructure, and promoting sustainable water management. • Novel log periodic feedlines-based ring filter detects water leakage in PVC pipes. • Resonant frequency adapt to water level changes, ensuring a reliable sensing system. • The filter is insensitive to vertical positioning errors at different heights of pipes. • Attenuation of varying pipe diameters shows consistent effectiveness of the filter. [ABSTRACT FROM AUTHOR]

The article titled "Chilling Module Rapidly Cools Samples for Leak Testing" discusses the Dry Chiller Module, which is used in container closure integrity testing (CCIT) in the pharmaceutical and medical industries. The module improves the testing process by rapidly cooling down containers without the need for a liquid bath, reducing testing time. It can be applied to helium pre-filled containers without any sample preparation, making it versatile in its applications. The module is an addition to the ASM 2000 and AMI 1000 leak detectors. [Extracted from the article]

Commercial refrigeration systems currently utilize refrigerants with global warming potential (GWP) values ranging from 1250 to 4000. The advent of low GWP alternatives (GWP <150) is expected to significantly curtail direct emissions from this segment and greatly influence the ongoing electrification and decarbonization efforts. Most of the low GWP alternatives exhibit flammability risk and hence require robust sensing solutions for a reliable and safe operation of the equipment. This review article aims to provide an overview of different sensing mechanisms suitable for potential applications in systems employing flammable refrigerants, particularly those designated as A2L class. A summary of different A2L refrigerants and their properties is provided followed by a broad review of different classes of sensors, their working principle, transduction method, features, advantages, and limitations. Additionally, key performance characteristics of accuracy, selectivity, sensitivity, dynamic characteristic, and durability among other properties are discussed. Finally, areas of improvement and corresponding approaches are suggested for potential sensors in the successful adoption of A2L class refrigerants.

The leakage and diffusion of hazardous gases from steam methane reforming (SMR) equipment are investigated by Flame Acceleration Simulator (FLACS) software to optimize the layout of combustible gas detectors. A typical accident scenario, with the gases leaked from converter tubes with leak apertures of 5 mm, 25 mm, and 100 mm and medium pressure of 0.1 MPa, 1 MPa, and 10 MPa, is established. At the same time, the influence of the environment wind speeds from 0.2 m·s−1 to 6 m·s−1 on the diffusion process is also investigated. The research results show that the leakage source concentration and diffusion distance positively correlate with the leakage aperture. Suggestion on the distance between combustible gas detectors and possible leak point is within 5 m, 10 m, and 15 m in the scenario of the leak aperture of 5 mm (small-hole leak aperture), 25 mm (middle-hole leak aperture), and 100 mm (big-hole leak aperture). The most dangerous scenario is at the static ambient wind speed, and the diffusion process strengthens with the raising of wind speed. The turning point scenario occurs at a wind speed of 1 m·s−1, where the flammable area is minimal. The medium pressure relates to the jet speed of the combustible gases. The wind speed should be comprehensively determined when considering the layout of the combustible gas detectors affected by this factor. The orthogonal experimental design shows that the most significant influence factor on the diffusion process of the combustible gas is the leak aperture, followed by the medium pressure and, finally, by the ambient wind speed. Recommendations are listed for the optimization of the layout of gas detectors in related enterprises. [ABSTRACT FROM AUTHOR]

We report the fabrication of vertical metal–oxide–semiconductor (MOS) detectors with the highest energy resolution ever reported. The MOS detectors have been fabricated on 50- $\mu \text{m}$ -thick n-type 4H-SiC epitaxial layers by growing a silicon dioxide (SiO2) layer thermally prior to contact deposition. The MOS detectors exhibited leakage currents two orders of magnitude lower than that observed in a Schottky barrier detector (SBD) fabricated on similar 4H-SiC epilayers. The MOS detectors exhibited a much higher energy resolution of 0.4% compared to 0.8% observed in an SBD for 5486-keV alpha particles although both the devices showed a high charge collection efficiency (CCE) of 96% when exposed to the alpha particles. Capacitance mode deep-level transient spectroscopy (C-DLTS) revealed the presence of “lifetime killer” $\text{Z}_{\mathrm {1/2}}$ defects in similar concentrations in both the devices, and however, the corresponding capture cross section in the SBD has been observed to be one order of magnitude higher compared to the MOS detector, and instead of EH6/7 center seen in the SBD, the MOS device showed the presence of EH5 center. The higher resolution of the MOS device is attributed to the lower leakage current and difference in defect configurations observed between the two devices. The MOS detector showed a positive polarity C-DLTS peak with an activation energy of 1.22 eV, which is likely due to the nonnegligible impedance of the back contact because of the SiO2 layer. The present study opens the great potential of other wide bandgap semiconductor-based vertical MOS detectors, which can be fully depleted for high-resolution X-/ $\gamma $ -ray detection. [ABSTRACT FROM AUTHOR]