scholarly journals Intelligent Mobile Wireless Network for Toxic Gas Cloud Monitoring and Tracking

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3625
Author(s):  
Mateusz Krzysztoń ◽  
Ewa Niewiadomska-Szynkiewicz
Keyword(s):  
Data Exchange ◽  
Mobility Model ◽  
Model Parameters ◽  
Toxic Substances ◽  
Cloud Detection ◽  
Gas Dispersion ◽  
Gas Concentration ◽  
Cloud Monitoring ◽  
Optimal Values ◽  
Gas Cloud

Intelligent wireless networks that comprise self-organizing autonomous vehicles equipped with punctual sensors and radio modules support many hostile and harsh environment monitoring systems. This work’s contribution shows the benefits of applying such networks to estimate clouds’ boundaries created by hazardous toxic substances heavier than air when accidentally released into the atmosphere. The paper addresses issues concerning sensing networks’ design, focussing on a computing scheme for online motion trajectory calculation and data exchange. A three-stage approach that incorporates three algorithms for sensing devices’ displacement calculation in a collaborative network according to the current task, namely exploration and gas cloud detection, boundary detection and estimation, and tracking the evolving cloud, is presented. A network connectivity-maintaining virtual force mobility model is used to calculate subsequent sensor positions, and multi-hop communication is used for data exchange. The main focus is on the efficient tracking of the cloud boundary. The proposed sensing scheme is sensitive to crucial mobility model parameters. The paper presents five procedures for calculating the optimal values of these parameters. In contrast to widely used techniques, the presented approach to gas cloud monitoring does not calculate sensors’ displacements based on exact values of gas concentration and concentration gradients. The sensor readings are reduced to two values: the gas concentration below or greater than the safe value. The utility and efficiency of the presented method were justified through extensive simulations, giving encouraging results. The test cases were carried out on several scenarios with regular and irregular shapes of clouds generated using a widely used box model that describes the heavy gas dispersion in the atmospheric air. The simulation results demonstrate that using only a rough measurement indicating that the threshold concentration value was exceeded can detect and efficiently track a gas cloud boundary. This makes the sensing system less sensitive to the quality of the gas concentration measurement. Thus, it can be easily used to detect real phenomena. Significant results are recommendations on selecting procedures for computing mobility model parameters while tracking clouds with different shapes and determining optimal values of these parameters in convex and nonconvex cloud boundaries.

STUDY OF GAS FUEL LEAKAGE AND EXPLOSION IN THE ENGINE ROOM OF A SMALL LNG-FUELED SHIP

2021 ◽  
Vol 161 (A3) ◽  
Author(s):  
Q G Zheng ◽  
W Q Wu ◽  
M Song
Keyword(s):  
Injury Risk ◽  
Engine Fuel ◽  
Limited Region ◽  
Gas Dispersion ◽  
Engine Room ◽  
Flammable Gas ◽  
Gas Fuel ◽  
Fuel Leakage ◽  
Gas Cloud ◽  
The Given

The engine fuel piping in LNG-fuelled ships’ engine room presents potential gas explosion risks due to possible gas fuel leakage and dispersion. A 3D CFD model with chemical reaction was described, validated and then used to simulate the possible gas dispersion and the consequent explosions in an engine room with regulations commanded ventilations. The results show that, with the given minor leaking of a fuel pipe, no more than 1kg of methane would accumulate in the engine room. The flammable gas clouds only exit in limited region and could lead to explosions with an overpressure about 12 mbar, presenting no injury risk to personnel. With the given major leaking, large region in the engine room would be filled with flammable gas cloud within tens of seconds. The gas cloud might lead to an explosion pressure of about 1 bar or higher, which might result in serious casualties in the engine room.

Study of Gas Fuel Leakage and Explosion in the Engine Room of a Small LNG-Fuelled Ship

2019 ◽  
Vol 161 (A3) ◽  
Keyword(s):  
Injury Risk ◽  
Engine Fuel ◽  
Limited Region ◽  
Gas Dispersion ◽  
Engine Room ◽  
Flammable Gas ◽  
Gas Fuel ◽  
Fuel Leakage ◽  
Gas Cloud ◽  
The Given

The engine fuel piping in LNG-fuelled ships’ engine room presents potential gas explosion risks due to possible gas fuel leakage and dispersion. A 3D CFD model with chemical reaction was described, validated and then used to simulate the possible gas dispersion and the consequent explosions in an engine room with regulations commanded ventilations. The results show that, with the given minor leaking of a fuel pipe, no more than 1kg of methane would accumulate in the engine room. The flammable gas clouds only exit in limited region and could lead to explosions with an overpressure about 12 mbar, presenting no injury risk to personnel. With the given major leaking, large region in the engine room would be filled with flammable gas cloud within tens of seconds. The gas cloud might lead to an explosion pressure of about 1 bar or higher, which might result in serious casualties in the engine room.

Simulation of Nitrate Concentration Affected from Land Use Changes in the Lower Part of Yom River Basin,Thailand: A Preliminary Study

2014 ◽  
Vol 931-932 ◽  
pp. 738-743
Author(s):  
Satika Boonkaewwan ◽  
Srilert Chotpantarat
Keyword(s):  
Land Use ◽  
River Basin ◽  
Swat Model ◽  
Land Use Changes ◽  
Sediment Concentration ◽  
Model Parameters ◽  
The North ◽  
Optimal Values ◽  
Preliminary Study ◽  
Year 2000

The Lower Yom River Basin is located in the north of Thailand. This study carried out to calibrate and validate using SWAT model in terms of streamflow and sediment concentration hydrographs (Year 2000-2012) for 3 RID streamflow gauging stations (the Royal Irrigation Department). The nitrates concentrations simulate have been influenced of land use changes during last ten years. Optimal values of model parameters derived from calibration and validation processes, which showed well fitted between observed and simulated results. In the last decade, particular in Lower Yom River, the land use change gradually transformed to be more paddy field and has been increased 127.48 km2 (approx. 0.87% increase), followed by urban area, which has been increased 196.66 km2 (approx. 1.35% increase), respectively. Average monthly concentration of nitrate increased 38.28 mg/l (approx.13.40 % increase), 43.17 mg/l (approx.12.00% increase), 43.02 mg/l (approx. 8.60% increase) at station Y.6, Y.4 and Y.17, respectively. Accordingly, on the basis of the results presented in this study, land use changes can significantly affect on concentrations of nitrate.

scholarly journals Explosion Characteristics of Hydrogen for CFD Modelling and Simulation of Turbulent Gas Flow

2018 ◽  
Vol 168 ◽  
pp. 07013 ◽  
Author(s):  
Jan Skřínský ◽  
Jan Koloničný ◽  
Tadeáš Ochodek
Keyword(s):  
Energy Demand ◽  
Gas Flow ◽  
Hydrogen Gas ◽  
Absolute Pressure ◽  
Gas Explosion ◽  
Cfd Modelling ◽  
Gas Dispersion ◽  
Turbulent Gas Flow ◽  
Gas Cloud ◽  
Chamber Gas

Renewable energies became more and more important in the last years. Hydrogen as a promising energy carrier is a perfect candidate to supply the energy demand of the world. The state of the hydrogen gas (turbulences and point concentrations) has a significant impact on the gas explosion indices. A gas cloud is formed by a partial-pressure method in gas explosion experiments in the spherical 20.0∙10-3 m3 chamber. Gas in the chamber reaches an uniform state beyond in hundreds of ms. The absolute pressure for gas dispersion should be higher than 0.01 MPa for the H2 of concentration larger than 30 vol. % of fuel. The initial temperature also influences turbulent gas flow before ignition, especially in the case of the gases lighter-than-air.

scholarly journals MODELS OF ECOLOGICAL AND ECONOMIC FUNCTIONS AS TOOLS OF DECISION SUPPORTING IN MARKET ECONOMY

2021 ◽  
Vol I (81) ◽  
pp. 102-114
Author(s):  
Vasyl Hryhorkiv ◽  
◽  
Mariia Hryhorkiv ◽  
Keyword(s):  
Decision Making ◽  
Linear Optimization ◽  
Practical Importance ◽  
Economic Models ◽  
Analytical Form ◽  
Model Parameters ◽  
Environmental Standards ◽  
Optimal Output ◽  
Optimal Values ◽  
Support Decision Making

There have been analyzed the possibilities of using different classes of models to support decision-making in terms of certainty in the management of ecological and economic systems, including optimization and functional ecological and economic models, which are closely related and in some sense are equivalent models. Such models include those describing ecological and economic interaction by means of the problems of mathematical and linear programming. The specificity of these models is that their optimal values are functions of МАТЕМАТИЧНІ МЕТОДИ, МОДЕЛ І ТА ІНФОРМАЦІЙНІ ТЕХНОЛОГІ Ї В ЕКОНОМ ІЦІ 104 Випуск І (81), 2021 model parameters that reflect both economic and environmental characteristics of the studied processes, so this type of model is an implicit reflection of the set of allowable values of their parameters in the set of optimal values of objective functions. These reflections are numerical functions of the dependence of optimal values on model parameters, which in the case of models of linear optimization can be constructed in an explicit analytical form, and their properties are close to the so-called neoclassical functions used in the theory of consumption, production and so on. The paper proposes optimization of ecological and economic models for maximization of output and profit from it. The target functions of these models are the functions of output and profit respectively, and the admissible set of used production resources are formed by the restrictions on economic and environmental resources of the manufacturer. The vectors of the maximum possible volumes of these resources are used to build, on the basis of these models, ecological and economic functions of optimal output and profit, that are the functional models of decision-making in ecological economy. These functions, like other models in this class, are an effective tool to support decision-making in practice as they are a more convenient tool for those responsible for making decisions and implementing them. The algorithm for constructing such functions and their peculiarity for practical application is substantiated, which lies in the fact that they model strict control over the manufacturer's compliance with environmental standards, motivates the manufacturer to adhere to environmental production standards and relevant environmental legislation. As decision-making models, the proposed models of ecological and economic functions are of great practical importance for the development of environmental standards and technological policy of the country or its regions.

scholarly journals Analysis of the Accidental Release of Chlorine

2019 ◽  
Vol 1 (1) ◽  
pp. 149-155
Author(s):  
Katarzyna Stolecka
Keyword(s):  
Meteorological Conditions ◽  
Water Supply Systems ◽  
Toxic Substances ◽  
Gas Concentration ◽  
Accidental Release ◽  
Continuous Release ◽  
Water Treatment Plants ◽  
Supply Systems ◽  
And Storage ◽  
Dangerous Level

AbstractDue to its properties, chlorine is one of the highly toxic substances used by humans. This gas attacks the respiratory system, eyes and skin. In higher concentrations, its inhalation leads to death. It is mainly used in water treatment plants where it guarantees a bacteriologically safe water in water supply systems. It is also used as a disinfectant and bleaching agent.The use, transport and storage of chlorine may pose serious hazard associated with its uncontrolled release from technological installations or tanks. The level of this threat will depend on the run of the release scenario or meteorological conditions. The article presents an analysis of the hazards associated with the uncontrolled release of chlorine. The ranges of zones with dangerous level of gas concentration are presented as a result of its instantaneous and continuous release.

scholarly journals Partially Mobile and Monolayer Adsorption of Gases on Energetically Homogeneous Adsorbent Surfaces

1994 ◽  
Vol 11 (1) ◽  
pp. 31-40 ◽  
Author(s):  
J.K. Garbacz ◽  
A. Kopkowski ◽  
D. Ziolkowska
Keyword(s):  
Graphitized Carbon Black ◽  
Model Parameters ◽  
Graphitized Carbon ◽  
Monolayer Adsorption ◽  
Different Temperatures ◽  
Adsorption Monolayer ◽  
Adsorption Of Gases ◽  
Optimal Values ◽  
The Individual ◽  
Mobile Adsorption

Isotherms of trichlorofluoromethane and trichloromethane adsorption on to the surface of P-33 graphitized carbon black measured at different temperatures have been described theoretically by applying the model of the partially mobile adsorption monolayer. It has been shown that the optimal values of the individual model parameters depend on the temperature according to the physical sense of these quantities.

MODELING DISPERSI EMISI BAU GAS SO2 DARI CEROBONG INDUSTRI TEKSTIL

2018 ◽  
Vol 4 (3) ◽  
Author(s):  
Teguh Prayudi
Keyword(s):  
Air Pollution ◽  
Textile Industry ◽  
Negative Impact ◽  
Exhaust Gas ◽  
Gas Emission ◽  
Gas Dispersion ◽  
Gas Concentration ◽  
Exhaust Gas Emission ◽  
So2 Concentration ◽  
So2 Gas

Textile Industry gives economic and fi nancial contribution to society, however it has negative impact to the environment, i.e. air pollution, bad smell and noise. For that reason, a study to evaluate exhaust gas emission of some industry textile was carried out from the stack. The aim of the study is to abtain SO2 gas concentration, which is emited from the stack A gas dispersion anlysis, it was indicated that SO2 gas concentration from the stack is still below the standard (1200 mg/m3). Thehighest SO2 concentration was 18 mg/m3 at about 200 meter away from the stack. It meant that SO2 concentration and SO2 odor from the textile industry did not give any impact to the environmentKey words: emission, textile industry,

Time series forecasting with model selection applied to anomaly detection in network traffic

2020 ◽  
Vol 28 (4) ◽  
pp. 531-545
Author(s):  
Łukasz Saganowski ◽  
Tomasz Andrysiak
Keyword(s):  
Anomaly Detection ◽  
Network Traffic ◽  
Model Parameters ◽  
Problem Solution ◽  
Quality Of Data ◽  
Initial Stage ◽  
Statistic Model ◽  
Short Memory ◽  
Optimal Values

Abstract In herein article an attempt of problem solution connected with anomaly detection in network traffic with the use of statistic models with long or short memory dependence was presented. In order to select the proper type of a model, the parameter describing memory on the basis of the Geweke and Porter-Hudak test was estimated. Bearing in mind that the value of statistic model depends directly on quality of data used for its creation, at the initial stage of the suggested method, outliers were identified and then removed. For the implementation of this task, the criterion using the value of interquartile range was used. The data prepared in this manner were useful for automatic creation of statistic models classes, such as ARFIMA and Holt-Winters. The procedure of calculation of model parameters’ optimal values was carried out as a compromise between the models coherence and the size of error estimation. Then, relations between the estimated network model and its actual parameters were used in order to detect anomalies in the network traffic. Considering the possibility of appearance of significant real traffic network fluctuations, procedure of updating statistic models was suggested. The results obtained in the course of performed experiments proved efficacy and efficiency of the presented solution.

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