Source Of Leakage Research Articles

Simulations of primary beam effects on the cosmic bispectrum phase observed with the Hydrogen Epoch of Reionization Array

ABSTRACT The 21 cm transition from neutral hydrogen promises to be the best observational probe of the epoch of reionization (EoR). The main difficulty in measuring the 21 cm signal is the presence of bright foregrounds that require very accurate interferometric calibration. Closure quantities may circumvent the calibration requirements but may be, however, affected by direction-dependent effects, particularly antenna primary beam responses. This work investigates the impact of antenna primary beams affected by mutual coupling on the closure phase and its power spectrum. Our simulations show that primary beams affected by mutual coupling lead to a leakage of foreground power into the EoR window, which can be up to ∼104 times higher than the case where no mutual coupling is considered. This leakage is, however, essentially confined at k < 0.3 h Mpc−1 for triads that include 29 m baselines. The leakage magnitude is more pronounced when bright foregrounds appear in the antenna sidelobes, as expected. Finally, we find that triads that include mutual coupling beams different from each other have power spectra similar to triads that include the same type of mutual coupling beam, indicating that beam-to-beam variation within triads (or visibility pairs) is not the major source of foreground leakage in the EoR window.

Digital Twin-Driven Performance Optimization for Hazardous Waste Landfill Systems

Hazardous waste landfill is the final way to dispose of hazardous waste and its environmental risk is different from that of domestic waste landfill. Its dangerous characteristics will not decrease with time, but will exist for a long. The environmental risks of hazardous waste landfills are concentrated in the probability risk of leakage of the impermeable layer. Therefore, it is of great significance to calculate the environmental risk of the leakage source intensity of typical hazardous waste landfills. In order to adapt to the personalized customer needs caused by social and economic development and to pursue new competitive advantages, the production mode of manufacturing enterprises is gradually changing to a small-batch and multi-variety customized mode. The complex and dynamic production environment caused by determinism puts forward higher requirements for the operation control accuracy of large-scale multiunit production systems. To support the efficient and coordinated operation of each link is a key challenge for process control of large-scale multiunit production logistics systems. This article proposes to accelerate the integration of information technology and manufacturing technology to promote the application of intelligent manufacturing process, intelligent logistics management, and other technologies in the production process. The research object is to study the multiunit linkage optimization problem under the framework of digital twin technology, through the real-time collaborative decision-making and feedback execution of the production, transportation, and warehousing multi-decision links to solve the “production-transportation-storage” decision-making in a dynamic environment. We analyzed the problems brought about by the dynamic interference of the execution process on the “production-transportation-storage” linkage operation process of the industrial park and analyzed the challenges of realizing the online linkage decision-making of “production-transportation-storage.” Based on the classic digital twin framework, a cross-unit digital twin linkage decision information architecture is proposed. Compared with the conclusions of the original environmental impact assessment report of the project, the post-environmental impact assessment results basically conform to the relevant descriptions, and a few nonconformities have been resolved during the project operation. The environmental protection measures of this project are relatively complete, which can meet various environmental protection requirements and enterprise development needs during the operation period of the project. For some environmental risks found in the process of project operation, evasion measures are proposed to reduce the possibility of environmental pollution accidents, and emergency measures can be taken in time when accidents occur. The practice of post-assessment of the environmental impact of this hazardous waste landfill is generally successful, and it has certain reference significance for the subsequent post-assessment of the environmental impact of other hazardous waste landfills.

A Review of National Monitoring Requirements to Support Offshore Carbon Capture and Storage

There is an urgent need to reduce global greenhouse gas emissions. One method of achieving this is through Carbon Capture and Storage (CCS). Geological structures that lie offshore under continental shelf seas offer huge CCS storage potential. An emerging marine industry is developing to exploit this potential and national marine monitoring agencies will soon need to consider the potential impacts of this emerging industry. This review of published literature is aimed at generalists responsible for the delivery of national marine monitoring, as well as those involved in the management of the marine environment. It briefly summarizes why the emerging offshore CCS industry is needed, how large it may be and what marine infrastructure may be involved. For the purposes of this paper, a hypothetical 20 Mtpa industry has been used to gauge the potential impact of a developing offshore CCS industry. The probability of CO2 leaks from such an industry is low. If they do occur, the spatial scale of impact will be small, and the potential environmental impacts will be low. Irrespective of how CO2 is transported or stored within shelf seas, leaked CO2 will enter the sea as a gas or as a solution dissolved in sediment pore water. CO2 as a gas will dissolve into seawater and/or directly vent to the atmosphere, depending on the initial conditions of the leak. The most probable source of leaks in a developed CCS industry is from pipelines (currently a 2-year event per 1000 km pipeline). The most probable source of leakage from geological storage is through abandoned wells (a 20- to 80-year event for a 20 Mtpa industry). The source of leaks from a CCS scheme with the potential to release the greatest mass of CO2 is through geological faults, as these may go undetected (if they occur) for long periods. The probability of leaks from geological storage, through faults or abandoned wells, is site dependent and minimized by the site selection process. The review concludes with recommended priorities for future marine science development.

Research on Super-resolution Location Technology of Leakage Source Based on Ultrasonic Array Sensor

Leakage in the pressure structure is a problem that must be paid attention to, especially in some special applications, such as spacecraft, which will have a serious impact on the entire system. This paper presents a new method of leak source location based on a single sensor array. The elastic wave excited by the leakage is collected by an array sensor placed on the wall, and then the frequency-space characteristics of these signals are analyzed to obtain the spatial point that meets these characteristics, that is, the spatial location of the leakage source. At the same time, combining the super-resolution technology and the randomness of the signal, integrating the distribution maps of the positioning results in different time periods, and finally obtaining a high-precision estimation of the location of the leakage source. The experimental results show that, under the conditions considered in this paper, the average value of the absolute positioning error on a square meter board is about 2 cm.

Posttraumatic pneumonectomy and management of severely contaminated pleural space.

Posttraumatic pneumonectomy and management of severely contaminated pleural space.

Three-dimensional localization of gas leakage using acoustic holography

Gas leakage localization is essential to prevent accidents from gas transportation or storage failures. There have been extensive studies on one-dimensional (1D) and two-dimensional (2D) gas leakage localization problem. This paper is the first to report the demonstration of a three-dimensional (3D) localization of gas leaks using far-field acoustic holography. This approach simultaneously provides 2D sound field imaging and depth position information regarding the leakage source. A virtual phased array composed of only two sensors collects the needed data, resulting in improved accuracy, enhanced feasibility and reduced cost. Various parameters, including the number of sensors, the spacing of array elements and the distance to the leakage source, are analyzed by a simulation of leakage sound field reconstruction. A series of experiments validated the effectiveness and accuracy of the proposed approach. Our results demonstrate that the proposed method achieves 3D localization and high-resolution imaging recognition of gas leaks.

Evaluating of IAQ-Index and TVOC Parameter-Based Sensors for Hazardous Gases Detection and Alarming Systems.

The measurement of air quality parameters for indoor environments is of increasing importance to provide sufficient safety conditions for workers, especially in places including dangerous chemicals and materials such as laboratories, factories, and industrial locations. Indoor air quality index (IAQ-index) and total volatile organic Compounds (TVOC) are two important parameters to measure air impurities or air pollution. Both parameters are widely used in gases sensing applications. In this paper, the IAQ-index and TVOCs have been investigated to identify the best and most flexible solution for air quality threshold selection of hazardous/toxic gases detection and alarming systems. The TVOCs from the SGP30 gas sensor and the IAQ-index from the SGP40 gas sensor were tested with 12 different organic solvents. The two gas sensors are combined with an IoT-based microcontroller for data acquisition and data transfer to an IoT-cloud for further processing, storing, and monitoring purposes. Extensive tests of both sensors were carried out to determine the minimum detectable volume depending on the distance between the sensor node and the leakage source. The test scenarios included static tests in a classical chemical hood, as well as tests with a mobile robot in an automated sample preparation laboratory with different positions.

The impact of sensor layout on Source Term Estimation in urban neighborhood

The layout of sensors in urban neighborhood has a great impact on the Source Term Estimation (STE) of dangerous or polluting gas leak sources. In this study, the effect of sensor layout on STE performance is analyzed using Computational Fluid Dynamics (CFD) approaches, and the best layout of sensors in the urban neighborhood is determined. The influence of source location and the border effect of measuring points on the performance of STE are analyzed. Results show that placing average two sensors around each building is the best sensor configuration for identifying source location parameters. Regarding the source intensity, no sensor configuration with obvious advantages has been observed. As the distance between pollutants and the city increases, the difficulty of STE increases. The result of STE is slightly more accurate and the posterior distribution is more concentrated after considering the border effect of measuring point.

Application of long short-term memory recurrent neural networks for localisation of leak source using 3D computational fluid dynamics

Gas leaks represent a major concern in industrial sites due to potential human and economical losses. Prompt identification of leak scenarios favours corrective maintenance avoiding the domino effect. In this paper, long short-term memory recurrent neural networks were trained and tested to CH4 leakage source in a chemical process module. We exploit the benefits of varying the temporal length of input variables, and the datasets were obtained employing 3D-CFD simulations. We consider four leak locations, four wind speeds, and eight wind directions, besides the non-leakage scenario for the same wind speeds and directions. The models were trained using different values of timesteps to evaluate the prediction accuracy for unseen data. Results showed progressive improvement of the performance of the models with greater values of timesteps, and good generalisation with test accuracy over 95.3%, indicating the ability of the model to correctly predict the leakage source using easily monitored variables.

Diagnosis and surgical repair of delayed tracheal perforation post thyroidectomy in context of previous cranio-spinal radiotherapy - A case report.

Introduction and importanceThis is the first case of delayed tracheal perforation post total thyroidectomy in the context of previous radiotherapy to the neck. Such a presentation can be easily misdiagnosed and managed as a seroma at significant risk to the patient, as the latter had no precipitating factors and cardiorespiratory compromise. There are nineteen previously described cases of delayed tracheal injury post thyroidectomy of variable severity and variable intervention.Case presentationA 51-year-old man presented with non-tender anterior neck surgical emphysema initially diagnosed on bedside ultrasound and plain X-ray, 22 days following total thyroidectomy and central neck dissection. His background was significant for childhood acute lymphoblastic leukaemia requiring chemotherapy and cranio-spinal radiotherapy. He underwent total thyroidectomy, for multiple bilateral thyroid nodules found on cranio-spinal MRI surveillance concerning for follicular neoplasm. There were significant amount of adhesions tethering the thyroid secondary to prior radiotherapy but no tracheal injury intra-operatively.Clinical discussionAt presentation, no source of air leak was identified on Computer Tomography. He failed conservative management. During surgical exploration, a 2 mm tracheal perforation at the right cricothyroid joint was closed with the right sternothyroid muscle due to the proximity of the perforation with the recurrent right laryngeal nerve. Tisseel was applied over the repair. He recovered without further complications.ConclusionSudden onset neck swelling post thyroidectomy in the context of significant scaring from radiotherapy, should raise the suspicion of surgical emphysema in the neck patients and confirmed with plain x-ray. Such patients should have multidisciplinary tertiary care.

Methane leakage source location based on a near-infrared off-axis integrated cavity output spectroscopic ppbv-level sensor and an optimized inverse model

Accurate location of methane (CH4) leakage source is essential for reducing air pollution and implementing effective countermeasures. A leakage source location method was proposed based on a near-infrared off-axis integrated cavity output spectroscopic parts-per-billion in volume (ppbv)-level CH4 sensor and an optimized inverse model. The CH4 sensor was developed for real-time, in-situ atmospheric CH4 monitoring in mobile measurement, which reveals an Allan variance of ∼7.99 ppbv and a response time of ∼8 s. The inverse model combines an improved particle swarm optimization (IPSO) algorithm with a gas turbulent diffusion model. To better solve the local optimal solution and premature convergence problems, optimizing the velocity of particle was presented in the IPSO algorithm. Through comparison, simulation results show that the location precision was increased by 69.14%, 61.43%, 36.61% and 69.81% under different source locations, wind speed, wind direction and moving speed, respectively. Also, five sets of field experiments were conducted to verify the performance of the IPSO, and the location precision was improved by 73.20%, 81.73%, 77.27%, 76.57% and 91.18%, respectively. Both simulation and field experiment results show that the IPSO algorithm has high precision and good robustness in source location. The proposed optimized inversion model provides a reference for the formulation or adjustment of emergency response strategies for gas leakage accidents.

Current Source and Distribution Pattern of Plastic Waste Leakage in the Estuary of Jakarta Bay

The accumulation of plastics in marine environment has increased the global risk of water pollution. Its uncontrolled production and existing management capacity have brought a burden on current plastic waste management, especially in Jakarta Bay. It has a negative impact on land, ecosystems, and especially the food chain and marine organisms. Their improper management has reduced the quality of environment, human health, and influenced economic sectors. Economic activities which involve coastal areas have consistently become a major source of plastic waste leakage either directly or indirectly. This study aims to analyze current source and its distribution patterns of plastic waste leakage in estuaries of Jakarta Bay using in-depth interviews and field observations. The results show the estuaries at the eastern part of Jakarta Bay is the highest potential for plastic waste leakage, followed by the western part, and the middle part is the least contributing plastic waste of leakage. The various sources of leakage in the estuaries are identified, including the behavior of the community that is vulnerable to exacerbates the existence of leakage. Handling capacities are limited including facilities, and the intensity of collection in the wide coverage of the operating area made the challenges to the responsible authorities.

Leakage source estimation by retrospective search for high concentration points in infrared gas concentrarion images

In recent years, there has been a concern about the occurrence of gas leakage and fire accidents in plant facilities due to damage caused by aging deterioration of gas piping. However, conventional gas leakage source estimation methods require prior teacher data or calculated data of gas clouds to be compared, which requires large computation time and may not be applicable under unexpected circumstances. Therefore, this study proposes a method to estimate the source of gas leakage by visualizing the leaking gas cloud using an infrared camera and performing an inverse problem analysis based on the concentration information without the need for prior teacher data or calculation data. It is found that the leakage source can be estimated by retrospective search from the gas concentration distribution to the location where the infrared absorption is large. In addition, the leak source estimation is achieved with high accuracy by removing the initial search position data and using only the position data near the leak source in the retrospective search.

Offshore Petroleum Leaking Source Detection Method From Remote Sensing Data via Deep Reinforcement Learning With Knowledge Transfer

A marine oil spill is an environmental pollution incident that generally has the attributes of a high speed, widespread, and long duration. It seriously threatens the marine ecological environment and related industries. It is vital to determine the source of the oil leakage so that it may be stopped and related hazards can be reduced. Oil spill accidents in the sea are generally located in offshore and navigation channels. With the rapid development of remote-sensing techniques, oil leak extraction using remote-sensing data has played an essential role in oil spill research. This paper proposes a Monte Carlo-based Deep Q-Transfer-learning Network (DQTN) offshore oil leak detection method that uses remote-sensing data. Remote-sensing data are utilized to continuously monitor a marine oil spill on the surface. The Estuarine and Coastal Ocean Model (ECOM) is utilized to simulate a marine oil spill event. The Deep Q Network (DQN) method with offline transferred knowledge is then utilized to determine the marine oil spill source location. In an experiment, based on the Bohai oil spill incident on June 2, 2011, the effectiveness of the remote-sensing-based DQTN marine oil spill search algorithm is verified. The accuracy of the targeted oil spill point is up to <inline-formula><tex-math notation="LaTeX">$98.97\%$</tex-math></inline-formula>.

Systematic Regulation of Personal Information Rights in the Era of Big Data

Big data has an important impact on people’s production and life. The existing legal and judicial protection, sanctions, and mechanisms for the enforcement of information rights have proved insufficient to stem the serious consequences of rampant leakage and illegal activity. Based on Information Full Life Cycle Theory, this article combines qualitative analysis with quantitative analysis, uses data from the Survey Report on App Personal Information Leakage released by China Consumers Association as an example, and finds that illegal access, illegal provisions, and illegal transactions have become important sources of personal information leakage. The main reasons for this problem include limitations of the technologies used, the falsification of informed consent, the lag of legislative protections, and a lack of administrative supervision. Systematic regulation of the right to protect personal information should include a variety of initiatives. First, it should be used to identify who to protect and how to protect them. Second, there needs to be a shift from identifiable subject regulations to risk control. Third, legislation needs to be comprehensive, entailing a shift from fragmented to systemic reforms. Fourth, protection efforts should include supervision, self-regulation, and management. Finally, the jurisdiction of legislation should extend across cyberspace and physical reality as a means to achieve a balance between effective protection and the reasonable use of personal information.

Аналіз зовнішнього впливу Російської Федерації на військовослужбовців збройних сил України через засоби мобільного зв’язку

The article examines the external influence of the Russian Federation (RF) on servicemen of the Armed Forces of Ukraine (AFU) through mobile communications. The purpose of the article is to systematize information on the use of mobile communications in the framework of the Russian Federation information and psychological impact on Ukrainian servicemen in the area of the Anti-Terrorist Operation (ATO). It was emphasized that the active influence on the servicemen of the Armed Forces of Ukraine by the units of the information operations of the Armed Forces of the Russian Federation is connected with the beginning of the Anti-Terrorist Operation (ATO) in Donetsk and Luhansk regions and continues to this day. The main forms of influence on the servicemen of the Armed Forces of Ukraine through the means of mobile communication are highlighted: sending messages of a demoralizing nature; determining the location of units of the Armed Forces for further fire damage; disruption of the cellular communication system with the use of electronic warfare; use of mobile phones as an additional source of leaks of official information; collecting information on the organizational and staffing structure of the Armed Forces. In order to demoralize the servicemen of the Armed Forces of Ukraine and disrupt the tasks assigned to them, SMS messages with threats and insults and telephone calls to the military and their relatives are actively used. The main ways of using mobile networks by the enemy, which give access to the intelligence services of the Russian Federation to information about the location of the subscriber: through the activities of companies providing mobile services that are wholly or partly owned by Russian citizens; through means of electronic warfare (military system RB-341V "Leer-3", which suppresses GSM communications through interference transmitted from unmanned aerial vehicles). The work of the commanders of the units of the Armed Forces of Ukraine on preventing the influence of the enemy through the means of mobile communication on Ukrainian soldiers is outlined. It was found out that during the fighting in the ATO (OOS) zone, servicemen were forbidden to carry individual means of communication (mobile devices) and information. These tools were used under the control of commanders at a strictly allotted time and place.

Research on reverse identification algorithm of indoor pollution source based on machine learning

Indoor sudden pollutant leakage brings environmental pollution and occupational exposure, so it is more and more important to obtain the location and identification of leakage sources. Through the forward method based on machine learning, this paper establishes a reverse traceability model for indoor multiple pollution sources. The POD method is used to obtain a large number of intermediate working condition data. The data pre-processing strategy of first normalization and then random forest feature screening can effectively improve the accuracy and generalization ability of the model. Based on a real environmental room case, model verification and sensor deployment optimization are carried out. The results show that the four sensors deployed in a specific location can achieve more than 95% positioning accuracy. In addition, the leakage possibility ranking component embedded in the model can effectively guide the staff to check the leakage points in turn, and the efficiency of three checks is as high as 99.91%.

Improved Harris Hawks Optimization algorithm based on quantum correction and Nelder-Mead simplex method.

Harris Hawks Optimization (HHO) algorithm is a kind of intelligent algorithm that simulates the predation behavior of hawks. It suffers several shortcomings, such as low calculation accuracy, easy to fall into local optima and difficult to balance exploration and exploitation. In view of the above problems, this paper proposes an improved HHO algorithm named as QC-HHO. Firstly, the initial population is generated by Hénon Chaotic Map to enhance the randomness and ergodicity. Secondly, the quantum correction mechanism is introduced in the local search phase to improve optimization accuracy and population diversity. Thirdly, the Nelder-Mead simplex method is used to improve the search performance and breadth. Fourthly, group communication factors describing the relationship between individuals is taken into consideration. Finally, the energy consumption law is integrated into the renewal process of escape energy factor E and jump distance J to balance exploration and exploitation. The QC-HHO is tested on 10 classical benchmark functions and 30 CEC2014 benchmark functions. The results show that it is superior to original HHO algorithm and other improved HHO algorithms. At the same time, the improved algorithm studied in this paper is applied to gas leakage source localization by wireless sensor networks. The experimental results indicate that the accuracy of position and gas release rate are excellent, which verifies the feasibility for application of QC-HHO in practice.

Leak Localization of Gas Pipeline Based on the Combination of EEMD and Cross-Spectrum Analysis

Pipeline transportation systems play an increasingly essential role in the development of the economy. An accurate location of leakage is important to reduce economic losses and maintain the safe operation of pipelines. In this article, a pipeline leakage detection method based on infrasound and negative pressure waves (NPWs) is adopted. This method can locate the leakage only by collecting the infrasound and pressure signals at the first station of the pipeline, which effectively solves the disadvantages of low positioning accuracy of a signal and easily produces false alarms. In this article, the signal denoising method of cross-spectral analysis combined with ensemble empirical mode decomposition (EEMD) was adopted. First, the leakage signals of sound waves and NPWs are processed by EEMD to obtain a series of intrinsic mode functions (IMFs). The characteristic frequency band is obtained by cross-spectral analysis of the leakage signal. Within this frequency band, the dominant component of the leakage source signal is divided by correlation analysis, and the IMF component is reconstructed to complete the signal denoising. When compared to the single signal pipeline leak detection method, the positioning accuracy of this article showed a 1–3 m improvement on average.

An Endogenous miRNA-Initiated Hybridization Chain Reaction and Subsequent DNAzyme Activation for Cellular Theranostics

An Endogenous miRNA-Initiated Hybridization Chain Reaction and Subsequent DNAzyme Activation for Cellular Theranostics