Leakage Alarm Research Articles

Research on Calibration device of gas leakage alarm system and uncertainty analysis

Abstract This paper studies the calibration device and method of the gas leakage alarm system, and evaluates the uncertainty of the measurement results. Firstly, it analyzes the important components, parameters, and working principles of the gas leakage alarm system. Then, it designs a set of inhalation-type gas leakage alarm system calibration devices to test the indication error, repeatability, and response time of the alarm system, and evaluates the uncertainty of the calibration device. The study concludes that the relative expanded measurement uncertainty of the device calibrating the alarm system is 2.6%, which meets the accuracy requirements of national standards for calibration devices. The main factors affecting the measurement results are the resolution and repeatability of the alarm system being tested. By improving the performance of the alarm system sensor, the measurement results of the alarm system can be made closer to the true value, reducing misjudgment and improving the accuracy of the system. And during calibration, the measurement capability of the device can be enhanced by using higher grade gas standard substances.

An optimized complementary design based on trilayer graphene oxide and clay composites for three stimuli responsive actuator

To promote the practical development of actuators, it is urgent to develop new multi-responsive actuators. Asymmetric bilayer actuators were reported to be dual-responsive, which can be driven by humidity and light. However, it remains a great challenge to develop rational designs for fabricating high-performance multi-responsive actuators. Here, we propose an optimized complementary design for three stimuli responsive actuators that can respond to multiple organic vapors, humidity, and light. The actuator is designed to achieve complementarity through a trilayer construction with graphene oxide (GO) in the middle layer, and with montmorillonite (MMT) and biaxially-oriented polypropylene (BOPP) on both sides, utilizing their hygroscopicity, organic vapor absorption, light absorption and thermal expansion capabilities. The maximum bending curvatures of the actuator under humidity, organic vapor and light stimulation conditions are 6.60 cm-1, 4.12 cm-1 and 2.59 cm-1 respectively, which are better than that of mixed GO-MMT/BOPP bilayer actuators. To reveal the kinetics of actuation, the actuation speed, temperature and mass during the deformation process are studied, which behave in sync with the bending curvature. Finally, a wireless intelligent claw and an organic-vapor leakage alarm are demonstrated based on these actuators. This study will provide an enlightening reference for multi-responsive actuators and promote their practical development.

P-doped W2C nanoparticles for hydrogen evolution reaction powered by a wind-driven triboelectric nanogenerator

Green hydrogen serves as a pivotal energy carrier in the pursuit of carbon neutrality; however, its production is constrained by costly catalysts and bulky power supply. Herein, we demonstrated P-doped W2C nanoparticles anchored on graphene (P @ W2C-C) as an efficient electrocatalyst for the hydrogen evolution reaction, powered by a wind-driven triboelectric nanogenerator (TENG). With an overpotential of just 179 mV and a Tafel slope of 87.8 mV dec−1, P @ W2C-C aligned well with the low power output of TENG. The TENG, utilizing rabbit hair and fluoroethylene propylene (FEP) as fraction materials, achieved a power density of 1.58 W m−2 by harnessing the kinetic energy of low-frequency wind. For demonstration, a hydrogen production rate of 64.5 μL min−1 and a self-awake hydrogen leakage alarm system were successfully realized. Moreover, the hydrogen production cost of this system was approximately 1.0 US$ kg−1 H2, where the levelized cost of energy constituted two-thirds of this expense and the remaining one-third was due to the electrolysis process. The synergistic integration of TENG and P @ W2C-C has opened a promising avenue for the high-efficiency and low-cost production of green hydrogen.

SmokePose: End-to-End Smoke Keypoint Detection

Smoke detection has been a research focus due to its application value in fire and toxic gas leakage alarms. Here we formulate a novel research paradigm for in-depth smoke analysis: modeling the smoke plume in an image with two semantic keypoints, i.e., the start-point (where the smoke comes from) and the end-point (where the smoke spreads), and localizing the keypoints through a heatmap-based detection method. A specialized dataset is developed for smoke keypoint detection, collecting images online and manually annotating the keypoints. Based on the dataset, we propose a Transformer-based model called SmokePose that employs a hierarchical Transformer encoder and a pure Transformer decoder to detect smoke keypoints in an end-to-end manner. We demonstrated the performance of the proposed SmokePose with comparative experiments and ablation studies. A further discussion on the visualization of the attention maps helps to understand the mechanism of SmokePose and to reveal essential image clues for smoke keypoint detection.

Fault detection of harmonic reducer for construction robot based on adaptive state observer

AbstractThe traditional manual masonry technology of building wall has the problems of low construction efficiency and poor safety. The research of automatic masonry robot has become an urgent need. Harmonic reducer is the key component to ensure the construction robot to achieve good quality construction. This paper takes the “flexible assembly” of harmonic reducer as the research object. The system dynamics model is simplified and the reducer fault mathematical model is established. An adaptive state observer with greater design freedom is designed based on the fault model. This paper introduces adaptive threshold and performs parameter optimization. When no fault occurs in the system, the distance between the adaptive threshold and the residual is small and higher than the residual. When the system fails, the residual is higher than the adaptive threshold. This method solves the fault leakage alarm of the traditional detection method with a fixed threshold. The effectiveness of the fault detection scheme under constant fault and time‐varying fault is verified by simulation. The results show that the adaptive threshold method can effectively reduce the false alarm whether the reducer has a constant fault or a time‐varying fault, which shows that the fault detection scheme designed in this paper is effective.

Application Research of Image Processing Technology for Fire Detection and Fire Alarm Based on Blockchain

Aiming at the problems of leakage alarms and false alarms in fire detection systems, this paper explores the commonality and characteristics of its development process through in-depth analysis of typical fire detection and fire alarm modes at home and abroad and effectively summarizes the process of building fire alarms. In the case of fully grasping the principles of fire alarm and related policy protection, find out the appropriate development mode of fire alarm. At the same time, it can also study the perspectives of the government, the market, and the public, according to the needs of the market, it can be driven by industry and technological innovation can be used as a strong support for the development of fire alarm. Finally, the results of example analysis show that: using blockchain, this paper can effectively obtain high-precision fire detection and fire alarm target analysis results, and meet the needs of real-time analysis of fire detection and fire alarm analysis. Experiments show that the system can detect fires correctly and quickly, and identify interference sources such as fluorescent lamps and alcohol lamps. It has strong interference and good economic benefits.

Information Security in Wireless Water Flow and Leakage Alarm System

Information Security in Wireless Water Flow and Leakage Alarm System

Pipeline leakage alarm via bootstrap-based hypothesis testing

To date, the research of transient-based pipeline leakage detection has been focused on the estimation of leak location and size, assuming at least one leak exists in the pipe system. However, due to the presence of aleatoric and epistemic uncertainties, fictitious leaks always appear in the estimation results even if the pipe is intact, such that the existing methods cannot quantitatively decide whether the estimated leaks really exist. This paper proposes a hypothesis testing framework so that the probability of the existence of leakage can be evaluated. To address the aleatoric uncertainties, the bootstrap method is employed to extract the information of the probabilistic distribution of leakage feature (i.e., the test statistics) from a very limited number of real-time transient measurements. The complex epistemic uncertainties are estimated from a baseline signal obtained from the same pipe system before leaks emerge. The distribution of the test statistics under the no-leak condition is then constructed so that the existence of leakage under the current condition can be determined with a given false alarm probability. Experimental results show that the proposed method accurately pinpoints the appearance of small leak and distinguishes it from the no-leak case, where the leak location and size are estimated simultaneously.

Design and Implementation of Level Control Management: Level Manager

Water is one of the basic needs of all living beings. Wastage of water is one of the most significant reasons for water shortage around the world. At the household level, overflow of water from the overhead tanks may happen without our knowledge. Hence to prevent this and to save water at least for a certain extent, implementation of an automatic water level manager can be a solution. Significance of the proposed system is that the device can detect the level of water in the overhead tank and according to the level of water, the motor pump is switched on/off automatically by Arduino. Level of water in the sump can also be monitored. The information is sent to the controller for a decision whether water has to be pumped to the overhead tank. Additionally, the system senses continuous flow of water, if present, as possible leakage and issues alarm.

Nanocomposite-Decorated Filter Paper as a Twistable and Water-Tolerant Sensor for Selective Detection of 5 ppb-60 v/v% Ammonia.

Ammonia (NH3) sensors proposed for the simultaneous exhalation diagnosis, environmental pollution monitoring, and industrial leakage alarm require high flexibility, selectivity, stability, humidity tolerance, and wide-concentration-range detection; however, technical challenges still remain. Herein, twistable and water-tolerant paper-based sensors integrated over surgical masks have been developed for NH3 detection at room temperature, via decorating specially designed ternary nanocomposites (ternary-NCs) on the commercial filter paper. The NCs consist of a multiwalled carbon nanotube framework with a polypyrrole nanolayer and are further loaded with Pt nanodots. Benefiting from the synergy effect of ternary components, the ternary-NCs exhibit an ultrasensitive response to 5 ppb-60 v/v% NH3 and present high selectivity confirmed by the theory calculations. Remarkably, the filter-paper-based sensors possess outstanding stability against twisting 0-1080°, along with excellent cuttability and foldability. Critically, such paper-based sensors can be integrated over surgical masks for simulated exhaled diagnosis and display superior water tolerance even being immersed in water for 24 h. Practically, the detecting accuracy of the filter-paper-based sensor toward the simulated exhaled NH3, environmental NH3 pollution, and industrial NH3 leakage is validated using ion chromatography.

Metal-Oxide Nanomaterials Synthesis and Applications in Flexible and Wearable Sensors.

Metal-oxide nanomaterials (MONs) have gained considerable interest in the construction of flexible/wearable sensors due to their tunable band gap, low cost, large specific area, and ease of manufacturing. Furthermore, MONs are in high demand for applications, such as gas leakage alarms, environmental protection, health tracking, and smart devices integrated with another system. In this Review, we introduce a comprehensive investigation of factors to boost the sensitivity of MON-based sensors in environmental indicators and health monitoring. Finally, the challenges and perspectives of MON-based flexible/wearable sensors are considered.

Analysis of natural gas leakage diffusion characteristics and prediction of invasion distance in utility tunnels

With the continuous development of urbanization, the number of underground supplies and demanded pipelines is increasing. In order to reasonably plan the construction of urban underground space, underground utility tunnels emerge, and show potential to reduce the difficulty of pipeline maintenance and repair. For natural gas pipelines laying in utility tunnels, however leakage accident can result in serious consequences. In this study, the numerical simulation method was used to analyze the leakage and diffusion characteristics of natural gas in utility tunnels under various working conditions, and the single-factor change and multi-factor change of different pressures, leakage diameters, ventilation conditions and leakage locations were investigated. The results showed that: the increase of pipeline operating pressure and leakage diameter could accelerate the diffusion velocity of methane in the utility tunnel. According to the prediction equation of methane invasion distance (MID) under natural ventilation condition, the average error was 8.29%. The mechanical ventilation condition accelerated the methane discharge and greatly reduced the distribution range and concentration of methane in the utility tunnel. In the single-factor change analysis, when the mechanical ventilation frequency was above 15times/h, the methane concentration at each monitoring point was below the lower explosion limit. No matter where the leakage occurs, the mechanical ventilation will prevent methane from diffusing upstream direction, and the downstream was at higher risk for methane distribution. The larger the coordinate value x of leakage location was, the smaller the distribution area of methane in utility tunnel was. When x = 90 m, the methane concentration at each monitoring point was 0. The prediction equation of MID under natural ventilation condition can provide reference for the installation distance of methane leakage alarm device. The research on methane diffusion characteristics under mechanical ventilation conditions provides suggestions for daily maintenance and accident prevention of gas pipelines in the utility tunnel.

Design of Smart Home Service Robot Based on ROS

At present, the functions of home service robots are not perfect, and home service robot systems that can independently complete autonomous inspections and home services are still lacking. In response to this problem, this paper designs a smart home service robot system based on ROS. The system uses Raspberry Pi 3B as the main control to manage the nodes of each sensor. CC2530 sets up a ZigBee network to collect home environmental information and control home electrical appliances. The image information of the home is collected by the USB camera. The human speech is recognized by Baidu Speech Recognition API. When encountering a dangerous situation, the GSM module is used to give users SMS and phone alarms. Arduino mega2560 is used as the bottom controller to control the movement of the service robot. The indoor environment map of the home is constructed by the lidar and the attitude sensor. The service robot finally designed and developed realizes the functions of wireless control of home appliances, voice remote control, autonomous positioning and navigation, liquefied gas leakage alarm, and human infrared detection alarm. Compared with the household service robots in the related literature, the household service robots developed by us have more complete functions. And the robot system has completed the task of combining independent patrol and home service well.

Sensitivity of water meters to small leakage

Water leakage beyond the meter at the household level is becoming an emerging problem in a world where water must be respected and saved. More than public awareness campaigns for citizens, automatic leakage detection could give in the future the best results. Domestic water consumption will be continuously monitored by smart meters able to distinguish between normal absorption and leakage. Nowadays, some research prototypes of smart water meters were designed for continuous monitoring aimed to collect measurements and send them to a central unit for developing statistics on consumptions and alarms. In this paper, the authors propose a battery-powered visual smart device that could be a good starting point to generate leakage alarms at the household level. After a brief description of state of the art, the paper at first faces the problem of the leakage detection dependence on meter sensitivity. Then, an image-based technique for automatic “null consumption detection” to be applied both to the register last digit and to a needle of water meters is tested on three different water meters. Finally, experimental results confirm that this image-based technique, allowing the automatic detection of Periods With Null Consumption, can be very useful for water leakage detection algorithms.

Development and Safety Evaluation of Earth Leakage Alarm Breaker Equipped with Fire Current (IGR) Alarming Function

The purpose of this study is to develop an earth leakage alarm circuit breaker, equipped with a leakage alarming function (JER-E2S, ETECKOREA Co., Korea), and to analyze its characteristics. The developed mechanism is exclusively used for single-phase and 220 V circuits, with a rated current of 32 A, 20 A, 20 A (for restrooms), 16 A, etc. It satisfies all characteristics of existing earth leakage circuit breakers (ELB). If a fire current, which is a resistive leakage current (Igr), flows through an electric line, the device detects the leakage current in real time and warns against the leakage through a blinking LED lamp. Since the developed device displays a tolerance to a capacitative leakage current (Igc) that inevitably occurs in LED lamps, communication devices, etc., it ensures a stable power supply. In addition, the earth leakage alarm circuit breaker protects against power failure due to a momentary ground fault. Therefore, it can supply power without the risk of the circuit breaker malfunctioning due to a momentary ground fault caused by water droplets, leaves, etc. Moreover, with a standby power of less than 0.1 W, the developed earth leakage alarm circuit breaker exhibits a power saving performance that is 3~8 times greater than that of other ELBs. Installation of approximately 10 earth leakage alarm circuit breakers in one apartment household, with an area of 120 m2, can save 2~5 kWh per month. Therefore, the developed earth leakage alarm breaker not only satisfies the characteristics of existing earth leakage breakers, but also exhibits outstanding power supply quality since it has the functions of electric fire prevention and malfunction prevention. Therefore, this device can innovatively contribute to electric fire prevention.

SOI Based Low Power Thermocatalytic Sensor with Nanostructured Gas Sensitive Material

Introduction Catalytic gas sensors are essential devices for detection of combustive gases near lower explosion limit (LEL). As the minimum power dissipation of Pt coil based sensors (pellistors) are 120 - 150 mW [1] intensive research is devoted to reduce it to be better compatible with portable devices while preserving sensitivity and stability. The reported microheater structures can operate up to 600 oC at a cost of 20-50 mW power consumption [2]. Nowadays the research activity is focused on development of stablenanostructured catalyst layer effective at low temperature, whereas compatible with MEMS thick film technology. Gas Sensitive Catalytic Materials The approach of fabrication gas sensitive material for coil and silicon membrane sensors is different. In first case the catalyst is bulky and forms bead or cylinder with diameter 400-500µm. In MEMS structures the catalyst is deposited on a microhotplate with a characteristic diameter of 100µm, de facto forming 2D surface. In the present work nanodespersed Al2O3 and ZrO2 ceramic carriers were prepared as presented on figs.5 and 6, respectively. Each material was divided into two equal parts - an active catalytic layer from one part and a comparative element from the second part were made exhibiting equal surface area. .In order to impregnate the catalyst support with the catalyst metal, salts of palladium chloride (PdCl2) and platinum acid (H2PtCl6) were used. Having annealed at high temperature metal clusters were formed in the catalyst support. Finally the active and reference materials were mixed with an organic binder to make the paste suitable for drop-coating deposition to MEMS silicone microheater. SOI Based MEMS Microheater Uniform and reproducible crystalline Si filaments were formed from SOI (silicon on insulator) wafers, because the buried oxide provides uniform thickness of the device layer and guarantees identical geometry. Cantilevers are suspended on stress compensated SiO2-Si3N4 membrane to increase their mechanical stability and eliminate their bending out of the original plane (fig. 1-4). Thereby the reduced stress provides longer lifetime. The higher resistivity of device silicon ensures higher filament resistance at the same temperature compared to its thin film metal reference, therefore the cross section of the current routes should be increased to achieve the sufficient resistance. A plausible advantage of the single crystalline filament material and the design is the minimized degradation effect of electromigration, thereby the lifetime of the heater is expected to achieve 6000-8000 hours. Moreover, the heated area of filament can be completely covered with catalyst or passive material, similarly to the coil-type filament devices.The opened side chip design facilitates catalyst deposition. Results and Conclusions Significant issues arise when the design of thermocatalytic sensors are transferred from the volumetric to the microplanar approach. First of all, the catalytic gas-sensitive layer must provide chemical activities:3∙10-6÷10-5mW/μm3. The solution of the problem is to choose classical materials alreadybeen used for many years in coil types pellistors - catalysts of platinum group metals on Al2O3 or ZrO2 ceramic carriers. The stability and behavior of these materials at high working temperatures has been already tested over tens of years in real working conditions (mains, gas line pipes, leakage alarm systems and etc.). The decrease in the quantity of the catalytic material deposited on the microheater leads to insufficient catalytic activity of the sensor as a whole. An increase in the operating temperature can correct the situation, but it is limited by the long-term stability of the microheater and the transformation of the crystallographic phase of the ceramic catalyst carrier. The critical temperature is around 550 °C. The Pt-Pd mixed-catalysts can be applied in the microplanar structure if uniform hotplate temperature is provided and the active and the reference sensing layers are deposited such as to minimize imbalance between the two elements. Acknowledgement This research was sponsored by the Sponsored by the National Research, Development and Innovation Office Foundation, Hungary, funding No. 2017-2.3.4-TeT-RU-2017-00006, and the Ministry of Science and Higher Education of the Russian Federation founding with unique identifier RFMEFI58718X0053.

A Micro-Controller Based Biogas Leakage and Fire Detection System

Most biogas units in the rural area have no smoke or fire alert safety mechanism. This has always resulted in indoor air pollution and or property damage in case of fire incidence. This unfortunate incident are preventable by installing a simple automated device to alert the owner in the event of smoke or fire for necessary action. This study focuses on a biogas leakage alarm system that alerts the owner via a buzzer, SMS, and call. The device uses an MQ-2 sensor to detect ignitable gas spillage and smoke. This high signal monitored by the Arduino Uno also leads to red LED lighting when the set smoke threshold is exceeded. The systems are portable and can be positioned in an appropriate position in the kitchen. This device is highly recommended in all the kitchens using biogas or firewood to alert the user in case of smoke indoor air pollution or fire breakout.

Strain-Sensitive Fluorescence from Two-Dimensional Organic Crystal.

Strain-sensitive fluorescence materials have great potential in sensing applications owing to their low cost, intuitive signal, and user friendliness. Organic crystals are one of the most developed fluorescence materials. However, modulation of the fluorescence by strain is still a challenge. Here, for the first time, we investigate the strain-sensitive fluorescence of the two-dimensional (2D) organic crystal. Without interlayer interactions, the molecular arrangement in a 2D crystal can be easily tuned, which results in photoluminescence transformation between monomer emission and excimer emission. The 2D organic crystal has higher sensitivity under strain, compared with bulk organic crystals, showing great potential in practical applications such as tactile monitors, chameleon bionic skin, and visible leakage alarms.

Product Design Evaluation Using Life Cycle Assessment and Design for Assembly: A Case Study of a Water Leakage Alarm

This study proposed the use of an LCA supported by a design efficiency evaluation based on Design for Assembly principles to reduce the environmental impact of a product. To illustrate the methodology, a water leakage alarm (WLA) was selected as the object for a case study. Based on the identification and evaluation of the LCA results, it was inferred that the stage with the highest environmental impact was the manufacturing stage (75.35%), followed by the use stage (23.88%), the disposal of the WLA (0.64%), and finally, the disposal of the batteries (0.14%). For the manufacturing stage, the most interrelated categories were the hazardous waste and human toxicity, while the use stage was the main contributor to ozone depletion and acidification. Moreover, the disposal of the WLA and batteries contributed to the bulk waste. Furthermore, from the assembly evaluation, the design efficiency of the product was 14%. Two recommendations for improving the design of the WLA were: (1) to reduce the number of screws from three units to one unit, and (2) to eliminate the use of a cable and to replace it with a wireless component. By implementing both the proposed recommendations, the design efficiency was improved by as much as 34%. From the environmental perspective, there is not much difference between the wired alarm and wireless alarm. The wired alarm was considered to be more environmentally friendly in terms of product manufacturing but the wireless alarm has an advantage in terms of design and energy efficiency. By combining LCA and DFA design evaluation, a more comprehensive perspective of the product life cycle can be achieved.

Ship cabin leakage alarm based on ARM SCM

If there is a leakage in the cabin of a sailing ship, it is a major accident that threatens the personnel and property of the ship. If we can’t take timely measures, there will be a devastating disaster. In order to judge the leakage of the cabin, it is necessary to set up a leakage alarm system, so as to achieve the purpose of detecting and alarming the leakage of the cabin, and avoid the occurrence of accidents. This paper discusses the design of ship cabin leakage alarm system based on ARM SCM. In order to ensure the stability and precision of the product, the hardware design of the alarm system is carried out, such as circuit design, software design, the programming of SCM, the software programming of upper computer, etc. It is hoped that it can be of reference value to interested readers.