Source Of Leakage Research Articles

Clinical usefulness of T1-weighted MR cholangiography with Gd-EOB-DTPA for the evaluation of biliary complication after liver transplantation.

Backgrounds/AimsBiliary complications continue to be the major morbidity and mortality causes following living donor liver transplantation (LT). Endoscopic retrograde cholangiopancreatography (ERCP) has been performed to identify the biliary leakage source. However, this can lead to retrograde cholangitis and pancreatitis, and is not sufficient to diagnose bile leakage from cuts’ surface. This study aimed to describe the use of T1-Weighted Magnetic Resonance (MR) Cholangiography with Gd-EOB-DTPA (Primovist) examination for evaluating the bile duct complication following LT.MethodsFrom March 2012 to December 2018, 869 adult LT were performed at the Seoul National University Hospital. Forty-three recipients had undergone MR Cholangiography with Gd-EOB-DTPA. We reviewed these cases with their clinical outcomes and described the utility of the MR cholangiography with Gd-EOB-DTPA.ResultsIn radiologic examinations performed in the patients suspected of bile duct complication, 95% had bile leakage and stricture. Cut surface leakage was diagnosed in two cases, and biliary leakage from the anastomosis site was diagnosed in the others. Most patients with leakage had undergone percutaneous drainage and ERCP, which was performed to evaluate the bile secretion function of the hepatocytes. There was no contrast-enhanced bile duct image in one case with severe rejection, and it might have been related to hepatocyte secretary dysfunction.ConclusionsT1-Weighted MR Cholangiography with Gd-EOB-DTPA 40-minute delay examination is a feasible and safe non-invasive procedure for identifying biliary leakage sites.

Wireless Sensor Networks for Detection and Localization of Subsea Oil Leakages

This work studies the impact of Wireless Sensor Networks (WSNs) for oil spill detection and localization in Subsea Production Systems. The case study is the Goliat FPSO, with a realistic assumption about the presence of a WSN built upon the existing passive acoustic sensors installed on each subsea template to monitor the manifold. The sensors take local binary decisions regarding the presence/absence of a spill by performing an energy test. A Fusion Center (FC) collects such local decisions and provides a more reliable global binary decision. The Counting Rule (CR) and a modified Chair-Varshney Rule (MCVR) are compared. An objective function based on the Receiver Operating Characteristic (ROC) is used for threshold design. The FC, in case of a spill detection, provides an estimated position of the leak source. Four localization algorithms are explored: Maximum A-Posteriori (MAP) estimation, Minimum Mean Square Error (MMSE) estimation, and two heuristic centroid-based algorithms. Detection and localization performances are assessed in comparison to the (position) Clairvoyant Chair-Varshney Rule (CVR) and to the Cramer-Rao Lower Bound (CRLB), respectively. The considered framework requires the prior knowledge of the involved subsea production system in terms of components that in case of failure would cause a leakage and their corresponding failure rates.

Spinal Compliance Curves: Preliminary Experience with a New Tool for Evaluating Suspected CSF Venous Fistulas on CT Myelography in Patients with Spontaneous Intracranial Hypotension.

Craniospinal space compliance reflects the distensibility of the spinal and intracranial CSF spaces as a system. Craniospinal space compliance has been studied in intracranial pathologies, but data are limited in assessing it in spinal CSF leak. This study describes a method to estimate craniospinal space compliance using saline infusion during CT myelography and explores the use of craniospinal space compliance and pressure-volume curves in patients with suspected cerebrospinal-venous fistula. Patients with suspected cerebrospinal-venous fistula underwent dynamic CT myelography. During the procedure, 1- to 5-mL boluses of saline were infused, and incremental changes in CSF pressure were recorded. These data were used to plot craniospinal space compliance curves. We calculated 3 quantitative craniospinal space compliance parameters: overall compliance, compliance at opening pressure, and the pressure volume index. These variables were compared between patients with confirmed cerebrospinal-venous fistula and those with no confirmed source of CSF leak. Thirty-four CT myelograms in 22 patients were analyzed. Eight of 22 (36.4%) patients had confirmed cerebrospinal-venous fistulas. Bolus infusion was well-tolerated with no complications and transient headache in 2/34 (5.8%). Patients with confirmed cerebrospinal-venous fistulas had higher compliance at opening pressure and overall compliance (2.6 versus 1.8 mL/cm H20, P < .01). There was no difference in the pressure volume index (77.5 versus 54.3 mL, P = .13) between groups. A method of deriving craniospinal space compliance curves using saline intrathecal infusion is described. Preliminary analysis of craniospinal space compliance curves provides qualitative and quantitative information about pressure-volume dynamics and may serve as a diagnostic tool in patients with known or suspected cerebrospinal-venous fistulas.

Does Employer-Paid, Job-Protected Maternity Leave Help or Hurt Female IT Workers? Evidence from Millions of Job Applications

Paid maternity leave is considered an important pathway to increasing women’s participation in IT because it helps address work and family balance concerns, which are pronounced in the field due to long hours, travel, and the need to keep up with technology. Many governments require that employers pay for maternity leave. Using micro-level data on millions of applications from an online job portal, our study examines whether a policy change in India that expanded employer-paid, job-protected maternity leave from short-term to medium-term (12 to 26 weeks) changes companies’ likelihood of considering female applicants to IT jobs and women’s likelihood of applying to such jobs. We find that post-legislation, there is a 4% decrease in the probability of women being invited for interviews and an 8% increase in the probability of a female applicant. Interestingly, in regions with low women’s labor force participation rates, we find a 31% decrease in the probability of women being invited for an interview, post legislation. In contrast, regions with high rates did not change their hiring practices, suggesting that the reform may increase regional inequality in women’s representation. Post legislation, women were significantly more likely to apply to jobs in regions with high women’s labor force participation rates relative to those with low rates. Our study identifies an important source of leakage in the pipeline for female IT workers and may inform policies aimed at reducing gender gaps in representation.

Sternberg's Canal and Defect: Is the Lateral Craniopharyngeal Canal a Source of Spontaneous Cerebrospinal Fluid Leak? Anatomic and Radiological Analysis in Pediatric and Adult Populations.

The lateral craniopharyngeal or Sternberg's canal (SC) originates from superior orbital fissure (SOF) and traverses the sphenoid body into the nasopharynx. A remnant of the canal, Sternberg's defect (SD), has been debated as a source of cerebrospinal fluid (CSF) leak. The canal was described in 1888, and there is limited accurate visual illustration in the literature. To provide a detailed anatomic and radiological illustration of the canal in pediatric and adult population including the mechanism undermining the incidence of the canal, and the possibility of the canal as a source of CSF leak. A total of 195 high-resolution computed tomographies (CT) of patients (50 3-yr-old, 20 5-yr-old, and 125 adults) and 43 dry adult skulls (86 sides) were analyzed for a canal matching the description of the SC. A SC was identified in 86% of the 3-yr-old and 40% of 5-yr-old patients. The diameter and length were 2.12 mm and 12 mm, respectively. The incidence of the canal decreased with age as sinus pneumatization extended into the sphenoid sinus. Only 0.8% of the adult skull on CT had the canal. The canal was not present on the dry adult skulls examination, but SD was found in 4.65%. SC exists with high incidence in the pediatric group. Sinus pneumatization obliterates the canal in the adult population, leaving a defect in 4.65% of cases, which given the location and related anatomic structures, is unlikely to be a source of CSF leak.

Use of tissue sealant patch (TachoSil) in the management of cerebrospinal fluid leaks after anterior cervical spine discectomy and fusion

Purpose The purpose of this study was to evaluate a fast, sutureless technique to repair anterior cervical dural tears. Anterior cervical discectomy and fusion (ACDF) is a commonly performed procedure for the treatment of cervical degenerative diseases. Although uncommon, incidental durotomy with cerebrospinal fluid (CSF) leak during ACDF is a potentially serious complication. Yet, its technical management for the prevention of CSF leak is controversial. Methods Between September 2012 and June 2018 we encountered seven cases (2 female/5 male) presenting with intraoperative CSF leaks secondary to incidental dural tears during ACDF surgery. All the cases were surgically treated using a topical fibrin sealant patch (TachoSil) with high adesive strength and fibrin glue (Tisseel). Intraoperative source of leakage, time to leakage control, quantity of Sealant Sponge used and postoperative complications were evaluated. Results Dural tears were tipically the result of dissection of adherent posterior longitudinal ligament and/or calcified disc from the cervical dural sac to allow full decompression of the spinal cord. Effective repair of dural tear defined as cessation of CSF leak after topical sealant agents application was achieved no later than one minute in all cases. Evident clinical and/or radiological postoperative CSF leak was used to determine the patient’s postoperative result. Postoperative CSF leak was not evident during a minimum 6 months follow up. Conclusions In the present study, we have reported our experience with a new sealing technique to manage CSF leaks from iatrogenic cervical dural lacerations. Tachosil tissue sealant patch is a rapid sutureless technique that may help in repairing introperatively incidental dural tears, thus reducing the risk of postoperative CSF leaks. To our knowledge, this is the first series to report the use of Tachosil adhesive sealant patch for the treatment of incidental dural tears during anterior cervical discectomy.

Neural network-based source tracking of chemical leaks with obstacles

The leakage of hazardous gases poses a significant threat to public security and causes environmental damage. The effective and accurate source term estimation (STE) is necessary when a leakage accident occurs. However, most research generally assumes that no obstacles exist near the leak source, which is inappropriate in practical applications. To solve this problem, we propose two different frameworks to emphasize STE with obstacles based on artificial neural network (ANN) and convolutional neural network (CNN). Firstly, we build a CFD model to simulate the gas diffusion in obstacle scenarios and construct a benchmark dataset. Secondly, we define the structure of ANN by searching, then predict the concentration distribution of gas using the searched model, and optimize source term parameters by particle swarm optimization (PSO) with well-performed cost functions. Thirdly, we propose a one-step STE method based on CNN, which establishes a link between the concentration distribution and the location of obstacles. Finally, we propose a novel data processing method to process sensor data, which maps the concentration information into feature channels. The comprehensive experiments illustrate the performance and efficiency of the proposed methods.

High-sensitivity gas leak detection sensor based on a compact microphone array

Early detection of tiny leaks in gas-pressurized vessels and pipelines can prevent disasters. Algorithm and sensor developments can enable acoustic methods to achieve high-sensitivity online leak detection by monitoring the sound generated by a leak and propagating in air. In this study, a compact MEMS microphone array-based sensor is proposed to detect very small gas leaks. Numerical calculation and experiment results show that the sensor gain (compared to a single microphone) is equal to the array element number when the azimuth of the leak source relative to the sensor is close to 0°. The proposed sensor can detect leaks as small as 0.67 mL/s emitted from a 0.1 mm hole at a distance of 20 cm. The bubble method can be used to enable the sensor to detect even smaller leaks, as low as 0.1 mL/s, at a distance of 10 cm using the burst sound of an invisible bubble.

3D Visualization Monitoring and Early Warning of Surface Deformation in Subsidence Area Based on GIS

Due to the large-scale mining of mineral resources, the surface strata in many areas have collapsed and even developed into deformation and subsidence. Based on the conventional geotechnical deformation monitoring technology, the surface deformation prediction and disaster caused by the conventional geotechnical deformation monitoring technology can be avoided. In this paper, based on GIS, combined with the analysis of surface settlement, the surface settlement, slope value, curvature deformation value, horizontal displacement, and corresponding horizontal deformation formula are comprehensively analyzed and studied. In order to make the surface deformation visualization and realize the high approximation processing with the subsidence area, this paper innovatively introduces the 3D visualization settlement data analysis and realizes the calculation result analysis and corresponding retrieval multiple visualization in the subsidence area depth prediction process. On this basis, the prediction data of subsidence area can be optimized and analyzed so as to master the efficient and accurate law of surface deformation. In the experimental part, a mine is taken as the experimental object, and the 3D visual monitoring processing is carried out. In this paper, the main method to prevent electromagnetic leakage of the computer system is the source suppression method. The source suppression method solves the problem fundamentally by reducing or eliminating the emission of computer electromagnetic leakage source. In the actual experiment, the effect of this method is very effective. The experimental results show that the prediction results and corresponding early warning accuracy of the system are significantly improved compared with the traditional scheme, which provides practical significance for disaster prevention and corresponding environmental impact assessment.

An adaptive leak localisation system based on a multi-level analytics framework in piping network

Leak localisation is a growing concern in water distribution system (WDS). The conventional time-correlation analysis incorporates with acoustic sensing is a feasible leak localisation technique in single pipeline system. However, this technique is impractical and time-consuming in a piping network due to multi-directional transmission waves from the leak source. In this paper, we propose an adaptive leak localisation system incorporating a remote-acoustic sensor network and a multi-level analytics framework (MLAF) for piping networks. The MLAF overcomes the multi-directional waves issue in piping networks. The system is adopted with an automated flow control algorithm to ensure time-effective localisation without needs of human supervision. The performance of MLAF has been evaluated based on several emulated piping networks with various network topologies. The characterisation results demonstrated high adaptiveness and location accuracies. The excellent results of field prediction in a local district metered area (DMA) further validated the feasibility of the MLAF.

Thermal characteristics of epoxy as a bonding material in a low temperature vessel

One of the main sources of heat leakage in a low temperature vessel is the thermal conduction of the vessel wall between room temperature and the low temperature. The material of the vessel is generally stainless-steel, and it is fabricated by welding. To reduce the amount of the thermal conduction, materials having low thermal conductivity are chosen. Glass fiber reinforced plastic (GFRP) is one of the adequate candidate materials because it has low thermal conductivity and high mechanical strength. We use GFRP pipe instead of stainless-steel pipe, as a neck in a liquid nitrogen vessel (or Dewar). Epoxy, as a bonding material, is inserted between the GFRP neck and the main body of the vessel. Therefore, the thermal characteristics, especially the thermal expansion, are very important because the vessel is cooled and warmed periodically. The experimental results of thermal expansion between room temperature and the low temperature are presented in the paper. Leakage in a vacuum environment is incurred because of different linear thermal expansion coefficients of various materials. The leakage is investigated using a vacuum-level checking method during the thermal cycle. In addition, the amount of boil-off in a low temperature vessel is discussed in terms of the thermal characteristics of the neck’s material.

Study on acoustic source characteristics of distributed optical fiber acoustic wave monitoring buried natural gas pipeline leakage

In order to study the leakage of buried natural gas pipeline caused serious environmental pollution and human casualties, the acoustic propagation characteristics of buried natural gas pipeline leakage monitored by distributed optical fiber were studied. At present, the research on the leakage of buried pipeline mainly focuses on the propagation of sound waves along the pipe wall, while the study on the propagation of sound waves in the soil is still lacking. The acoustic attenuation of acoustic wave propagation in soil by the size of leakage hole and leakage pressure is studied, and the evolution process of acoustic wave in soil is revealed. The conclusion is that the acoustic source of buried natural gas pipeline leakage belongs to broadband noise, and the acoustic energy of leakage is prominent in the low frequency band of 15kHz. The lower frequency, the higher sound pressure level. The oscillation of the sound pressure level attenuates with the increase of frequency. Fiber optic monitoring of buried natural gas pipeline leakage early warning provides theoretical support for the conclusion. The sound pressure level in low frequency band is of great significance for buried pipeline leakage monitoring.

Захист комерційної таємниці в контексті стратегічного управління економічною безпекою організації в умовах цифровізації економіки

The article substantiates the relevance of developing the mechanism for protecting commercial secrets of the organization in the system of strategic management of economic security of the organization, taking into account the transformational changes in the economy. Using the methods of synthesis and analysis, logical and generalizing methods, the authors determined the essence and basic features of the concept of "commercial secret" in both legal and scientific literature. The most common threats to commercial secrets have been identified and the sources of threats to the leakage of confidential information have been identified, taking into account the digitalization of economic processes. Four areas of protection of commercial secrets of an organization have been identified: legal, organizational, technical and psychological. The importance of providing valuable information in the strategic perspective of commercial secrets for the formation of the basis for its protection in future were highlighted, as well as those responsible for protecting this information with the consolidation of duties and responsibilities in collective and employment agreements were identified. In the context of formation of an effective system of strategic management of economic security of organizations in the conditions of transformational changes the directions of improvement of protection of a commercial secret are offered. Taking into account a growing share of cyber fraud and transition to the preservation of information mainly on digital media, the urgency of enhanced protection increases. Thus, the formation of information security using advanced technologies and equipment, attracting highly qualified specialists in this field, monitoring to identify potential sources of information leakage and eliminate them. Considering that most common source of disclosure of trade secrets is the staff of the organization, it is proposed to form a long-term loyalty of employees and their understanding of the importance of protecting confidential information, the introduction of socially oriented personnel strategy.

Research on frequency parameter detection of frequency shifted track circuit based on nonlinear algorithm

Abstract The basic task of railway signal work is to ensure safe and smooth transportation, improve transportation capacity, and improve transportation conditions and quality. Since it carries important information and control technology; it must be characterized by high security and high reliability. To address the aforementioned issues, this study uses a nonlinear technique to provide high-precision real-time detection of frequency shift signal parameters, based on an investigation of the sources of spectrum leakage in the FFT transformation. It not only reduces the sampling time but also the computation time when compared to the nonlinear method. This paper presents a frequency shift track circuit parameter based on nonlinear algorithm, studies the application of frequency shift signal parameter detection based on nonlinear algorithm, and simulates it with MATLAB. The experimental results show that the errors of center frequency, low frequency, and frequency offset are distributed in the range of ±0.05 Hz, ±0.005 Hz and ±0.15 Hz, respectively, which meet the parameters of frequency shift signal. The algorithm can meet the requirement of technical indexes and shorten the sampling time, which provides a theoretical basis for the design of the real-time frequency shift signal parameter tester.

Identifying Oil Spill Types Based on Remotely Sensed Reflectance Spectra and Multiple Machine Learning Algorithms

An accurate identification of oil spill types is the basis of determining the source of leakage, evaluating the potential damage, and deciding a plan of responses for an oil spill event. Despite sufficient studies that interpreted and analyzed hyperspectral data of oil spills, these studies that identify or classify oil spill types is rather limited. Aiming at identifying different types of oil spills, this article analyses the reflectance spectra obtained from high-resolution hyperspectral sensors using multiple machine learning methods. Four types of machine learning models are applied in this article: random forest; support vector machine (SVM); and deep neural network (DNN); and DNN with differential pooling (DP-DNN). The training and testing data are collected by field experiments under different environmental condition in order to verify the robustness of the machine learning models. The characteristics of reflectance is briefly described, and the results conform with results from previous studies. The performances of the machine learning models are evaluated and compared in terms of both accuracy of prediction and computational complexity. The results indicate that the two DNN models are able to achieve the most accurate prediction among the four machine learning models at the cost of more computation. The SVM model, or the proposed DP-DNN model may be a favorable choice when training time is limited.

Back Calculation of Leakage Accident Source Term of Liquid Ammonia Gas Storage Tank

Ammonia is a colorless and toxic gas. Due to its fast leakage rate, the leakage port is not easy to detect, and it is often difficult to seal it, causing more serious personal injuries and property losses. So it is a key problem to predict the intensity and location of toxic and harmful gas leakage quickly and accurately. Then it needs to combine the atmospheric diffusion model and optimization algorithm to establish the source term information back calculation model, and solve the location and intensity of the leakage source based on the concentration data of the downwind direction of the leakage source. Based on the analysis of the physical and chemical properties of ammonia, according to Wilson plume rising experience formula and Gauss plume model, the leakage model of liquid ammonia storage tank is established, and the effective monitoring points are extracted. According to the concentration of simulated monitoring points, the source information is calculated by particle swarm optimization algorithm. The feasibility of this method in the leakage of liquid ammonia storage tank is verified, which can help emergency response of accidents.

Leakage source estimation based on gas cloud formations obtained from infrared visualization measurements

Leakage source estimation based on gas cloud formations obtained from infrared visualization measurements

Location of the Leakage From a Simulated Water-Cooling Wall Tube Based on Acoustic Method and an Artificial Neural Network

Water-cooling wall tube leakage accident is an important factor affecting the safe and economic operation of power station boilers. In this article, the acoustic method is applied to locate the leakage from a simulated water-cooling wall tube, and several key technologies are studied in order to identify the precise location of leakage source. Sound wave propagation path in ‘nonuniform temperature field is obtained to overcome the shortcoming that the traditional location technology always assumed that sound waves propagate along the straight line. Considering the refraction effect of sound waves, the reconstruction method based on radial basis function approximation with polynomial reproduction (RBF-PR) is used to reconstruct the temperature field. A generalized cross correlation with second correlation is applied to estimate the time delay of arrival (TDOA). According to the temperature field measured by acoustic method and the propagate time of sound waves, the location fingerprint method including the statistical correlation characteristics between the coordinate of fingerprint points and TDOA are constructed. Radial basis function artificial neural network (RBF ANN) is used to estimate the coordinate of leakage point. Numerical simulations and experimental study are implemented to evaluate the effectiveness of the proposed location system. An acoustic location test platform is constructed to study the location accuracy in different working conditions. The results indicate that considering the refraction effect, the reconstruction performance of temperature field is superior than that without the refraction effect, and acoustic method with RBF ANN algorithm can gain the leakage location with high accuracy and good antinoise ability in the above high-quality reconstructed nonuniform temperature distribution.

E3 Metals increases the performance of its direct lithium extraction technology.

The risk of leakage along existing wellbores associated with CO2 sequestration depends strongly upon the leakage path permeabilities. If enough buildups of surface casing pressure (SCP) and rates of surface casing vent flow (SCVF) recorded on intermediate wellbore casing strings are available, a frequency distribution of leakage path permeability values can be obtained. Uncertainty about the location of the leak source results in a range of leakage path permeability values for each measurement of SCP or SCVF. Most permeability values exceed intact cement permeability, consistent with the presence of cracks or other defects in the formation/cement/casing interface. Assuming the gas migration path through leaky wellbores in hydrocarbon reservoirs is analogous to the leakage path for CO2 plumes, the distribution of inferred permeabilities enables quantitative estimation of CO2 leakage fluxes.

A GALS Pipeline DES Architecture to Increase Robustness against CPA and CEMA Attacks

Side channels attacks (SCAs) are very effective and low cost methods to extract secret information from supposedly secure cryptosystems.The traditional synchronous design flow used to create such systems favors the leakage of information, which enables attackers to draw correlations between data processes and circuit power consumption, electromagnetic radiation or other sources of leakage. By using well known analysis techniques, these correlations may allow that an attacker retrieves secret cryptographic keys. Differential Power Analysis (DPA) and Differential Electromagnetic Analysis (DEMA) are among the most cited attack types. More accurate types of attacks have been proposed, including Correlation Power Analysis (CPA) that associates power quantities with a specific power model. In recent years, several countermeasures against SCAs have been proposed. Fully asynchronous and globally asynchronous locally synchronous (GALS) design methods appear as alternatives to design tamper resistant cryptosystems. However, according to previous works they use to achieve this with significant area, throughput, latency and power penalties and are not absolutely secure. This paper proposes a new GALS pipeline architecture for the Data Encryption Standard (DES) that explores the trade-off between circuit area and robustness to SCAs. Robustness is enhanced by replicating the DES hardware structure in asynchronously communicating module instances, coupled with self-varying operating frequencies. Designs prototyped on FPGAs with the proposed technique presented promising robustness against attacks, after submitted to differential and correlation analyses. This is true for both power and electromagnetic channels. Additionally the proposed architecture displays throughput superior to previously reported results.