Leakage Phenomenon Research Articles

Experimental Investigation of Plume Diffusion Behavior of LNG Accident Release Underwater

To deal with the significantly serious problem of environmental pollution, the use of clean energy is vigorously promoted by governments and corporations in all countries. Therefore, the offshore transportation and trade of LNG has become the main way of energy supplication in cross regional. The potential risk of LNG release from ships or offshore pipelines may cause disastrous consequences, which requires a better consideration and evaluation of the consequences of LNG accidental release. The main purpose of this paper is to understand the special physical phenomena of LNG underwater leakage and the dynamic behavior of rising plume. A small-scale indoor underwater leakage experimental platform was designed and built in a wind tunnel. The plume rising behavior of underwater release of the cryogenic liquid were recorded by a high-speed camera. Through the image processing techniques, the physical model of cryogenic liquid heat transfer underwater was established and verified. In addition, the effects of different sizes and pattern of the orifices and release pressures on plume radius were evaluated. An empirical relationship for predicting the plume diffusion radius under different pool sizes was established based on the method of dimensionless analysis.

Detection of individual spin species via frequency-modulated charge pumping.

We utilize a frequency-modulated charge pumping methodology to measure quickly and conveniently single "charge per cycle" in highly scaled Si/SiO2 metal-oxide-semiconductor field effect transistors. This is indicative of detection and manipulation of a single interface trap spin species located at the boundary between the SiO2 gate dielectric and Si substrate (almost certainly a Pb type center). This demonstration in sub-micrometer devices in which Dennard scaling of the gate oxide has yielded extremely large gate oxide leakage currents eliminates interference between the charge pumping current and the leakage phenomenon. The result is the ability to measure single trap charge pumping reliably and easily, which would otherwise be completely inaccessible due to oxide leakage. This work provides a unique and readily available avenue for single spin species detection and manipulation, which can be applied as a quantized standard of electrical current as well as to serve as a potentially useful platform for developing quantum engineering technologies. Finally, we discuss potential underlying physical mechanisms that are involved in producing a seemingly contradictory measure of both odd and even integer values for charge per cycle.

Wading through Molasses: A qualitative examination of the experiences, perceptions, attitudes, and knowledge of Australian medical practitioners regarding medical billing.

Medical billing errors and fraud have been described as one of the last "great unreduced healthcare costs," with some commentators suggesting measurable average losses from this phenomenon are 7% of total health expenditure. In Australia, it has been estimated that leakage from Medicare caused by non-compliant medical billing may be 10-15% of the scheme's total cost. Despite a growing body of international research, mostly from the U.S, suggesting that rather than deliberately abusing the health financing systems they operate within, medical practitioners may be struggling to understand complex and highly interpretive medical billing rules, there is a lack of research in this area in Australia. The aim of this study was to address this research gap by examining the experiences of medical practitioners through the first qualitative study undertaken in Australia, which may have relevance in multiple jurisdictions. This study interviewed 27 specialist and general medical practitioners who claim Medicare reimbursements in their daily practice. Interviews were recorded, transcribed, and analysed using thematic analysis. The qualitative data revealed five themes including inadequate induction, poor legal literacy, absence of reliable advice and support, fear and deference, and unmet opportunities for improvement. The qualitative data presented in this study suggest Australian medical practitioners are ill-equipped to manage their Medicare compliance obligations, have low levels of legal literacy and desire education, clarity and certainty around complex billing standards and rules. Non-compliant medical billing under Australia's Medicare scheme is a nuanced phenomenon that may be far more complex than previously thought and learnings from this study may offer important insights for other countries seeking solutions to the phenomenon of health system leakage. Strategies to address the barriers and deficiencies identified by participants in this study will require a multi-pronged approach. The data suggest that the current punitive system of ensuring compliance by Australian medical practitioners is not fit for purpose.

Thrust ripple analysis for improved modular tubular permanent magnet synchronous linear motor

Various technologies have ever been developed to minimize the detent force of linear motors. Although the traditional modular structure can effectively reduce the detent force, the width of the flux barrier and the number of units severely limit its application. To solve these, this paper proposes a new modular type of tubular permanent magnet synchronous linear motor (TPMSLM), which consists of two identical unit motors. For simplification, a subdomain analytical method of the unit motor is firstly established, and its accuracy is verified by a comparison with that of the finite element method. Using the two approaches, the important parameters of the motor are analyzed. A modified two-unit modular TPMSLM is also proposed through the star vectograms of the electromotive force, which achieves thrust performance similar to the traditional three-unit modular TPMSLM with a smaller axial size. Moreover, to make full use of the volume of the flux barrier, end teeth are added at both ends of the unit motors. The simulation results indicate that a reasonable end tooth structure can not only reduce the magnetic leakage phenomenon of the end but also effectively improve the thrust of the motor.

A Novel Channel Errors Calibration Algorithm for Multichannel High-Resolution and Wide-Swath SAR Imaging

For a spaceborne high-resolution and wide-swath synthetic aperture radar (HRWS-SAR) system, it usually uses the digital beamforming technology. However, in practice, because of the influences of temperature, antenna pattern, receiving antenna, and other error factors, there may exist the range synchronization time errors, amplitude errors, and phase errors among different spatial channels. These nonideal factors will significantly degrade the multichannel data reconstruction performance, resulting in a smeared SAR image. To address this issue, in this article we propose a novel channel error correction algorithm based on the orthogonal projection theory. First, the optimal weight of each Doppler ambiguity component is calculated by the orthogonal projection. Then, the cost function is constructed based on the power maximization criterion, from which the channel phase errors can be obtained. Finally, the HRWS-SAR imaging can be finely realized after performing the channel balancing. Compared with the conventional phase error estimation method, the proposed algorithm does not require to perform the matrix eigenvalue decomposition, avoiding the signal leakage phenomenon under low SNR case. The effectiveness of the proposed algorithm is validated by both airborne and space-borne real SAR data.

NUMERICAL PREDICTION OF SLAMMING LOADS DURING WATER ENTRY OF BOW-FLARED SECTIONS

The two-dimensional water entry of bow-flared sections is studied by using a Multi-Material Arbitrary Lagrangian- Eulerian (MMALE) formulation and a penalty-coupling algorithm. A convergence study is carried out, considering the effects of mesh size, the dimension of fluids domain, and fluid leakage phenomenon through the structure. The predicted results on the wetted surface of a bow-flared section are compared with published experimental values in terms of vertical slamming force, pressure distributions at different time instances and the pressure histories at different points. Comparisons between the numerical results and measured values show satisfactory correlation. An approximation method is adopted to estimate the sectional slamming force showing good consistency for the peak forces.

Effect of Soybean Phosphatidyl Ethanolamine on the Formation and Properties of Pickering Emulsion Stabilized by Hemp Protein Isolate

This paper studied the effect of soybean cephalin on hemp protein isolated Pickering emulsion properties. The emulsifying activity index, the microstructure, droplet size, Zeta potential, the influence of rheological properties and storage stability were measured. It was critical to explore the influence mechanism of hemp protein isolated Pickering. The results showed that the stability of Pickering emulsion was improved after the addition of cephalin. The optimum indexes of the Pickering emulsion were obtained when the amount of cephalin was 30%, with an emulsion activity index of 4.63 m2⁄g and a dispersion index of 0.23. The droplet size was 125 nm, and the Zeta potential was -27.12 mV. The apparent viscosity of the emulsion was small. There was no obvious droplet aggregation and oil leakage phenomenon after 7 days storage, therefore the storage stability was good. This study provided a theoretical basis for improving the stability of hemp protein isolate Pickering emulsion, which could also expand the application field of soybean cephalin.

Electron-beam-induced current (EBIC) imaging technique to quicken polysilicon defect localization in MOSFETs

It is demonstrated that EBIC imaging technique is superior in quick localizing polysilicon defect of metal-oxide-semiconductor field-effect transistors (MOSFETs). Once polysilicon leakage phenomena are examined, relying on EBIC imaging analysis, we can rapidly isolate nanoscale defect in tens of microns length range. Although faulty polysilicon is employed by more than one MOSFET, it turns out to be unnecessary to characterize all devices after EBIC imaging analysis. By comparative studies, it is concluded that 2-probe EBIC imaging is preferred for mega-Ohm range resistive defect localization while 1-probe configuration is only applicable for kilo-Ohm range. Nanoprobe I-V measurement of the isolated device uncovers the abnormal electrical characteristic which fairly aligns with EBIC imaging analysis. Focused ion beam (FIB) and transmission electron microscopy (TEM) findings imply the EBIC imaging has submicron level spatial resolution toward resistive defects. Therefore it overcomes traditional limits in terms of technical method and lowers failure analysis (FA) difficulty considerably. Ultimately, a simplified model is proposed to explain the physical mechanism of this application. Our modeling describes the strong dependance of EBIC imaging on hot excess carrier behavior within shallow p-n junction when electron beam (e-beam) penetrates into bulk silicon. The work improves the understanding of excess minority carriers transport properties in p-n junction under scanning e-beam irradiation. And this paper may make EBIC imaging be a more promising way to identify minute material defect of future advanced MOSFET.

Coupled computing for reactive hydrogen leakage phenomena with crack propagation in a pressure tank

This research focuses on reactive hydrogen leakage due to the fracturing of high-pressure hydrogen tanks to develop a coupled computing method that can simultaneously perform reactive fluid-structure interaction analyses. The integrated computational approach to reactive hydrogen leakage with combustion due to wall crack propagation was implemented using a hybrid of the coupled particle and Eulerian methods. This computational method provides valuable safety information for predicting crack propagation and hydrogen leakage with combustion reaction in pressure tanks as an essential part of assessing hydrogen as an energy vector. As a result, the effect of crack formation and wall boundary conditions on hydrogen turbulent diffusion and concentration distribution and the thermodynamic behavior of the chemical reaction were predicted computationally. It was found that a combustion reaction does not occur near the streamwise axis at the duct center because there is an excess of hydrogen fuel, which increases scalar dissipation, and that the combustion reaction separated into upper and lower regions as it proceeded.

Leakage analysis of campus water supply system based on MLP neural network

Water supply system is an important part of campus public facilities, and the water supply pipeline will leak, not only increase the cost of water supply, but also cause water waste. This paper collects water consumption data of water meters at all levels in a school’s water supply system, establishes MLP multilayer perceptron neural network model, determines the water leakage rate according to the fluctuation of predicted value and actual value, so as to analyze the leakage situation of each school’s water supply system. When the fluctuation between the actual and predicted water consumption exceeds a certain threshold, water leakage occurs on that day. Through solving the model, the following conclusions are finally drawn: (1) the annual water leakage rate of the school is 10.74%, and the water leakage is 29131.418L. (2) The water leakage rate in the first quarter is the highest, and the water leakage in the second quarter is the highest.(3) The school aquaculture area is the most serious leakage phenomenon, and the maximum water leakage rate of each water meter node is more than 10%.

Study on the Physical Properties of Split-type Iron Base Shape Memory Alloy Pipe Joint

Aiming at the leakage phenomenon of pipeline system due to corrosion and other reasons, a split type iron-based shape memory alloy pipe joint based on the button bond connection was designed for repair. This split-type pipe joint can be used for quick in-situ maintenance of pipelines without cutting off pipelines or stopping transmission without pressure relief. It is especially suitable for intensive pipeline maintenance and online emergency maintenance. In order to study the connection performance of the split iron-based shape memory alloy pipe joint, this paper took the Fe17Mn4Si10Cr4Ni alloy pipe joint as the research object, and carried out pressure sealing and pull-out experiments respectively on the integral pipe joint and the split pipe joint which had not been carried out and had been subjected to one heat and mechanical training. The results showed that, compared with the integral pipe joint, the pressure seal value of the split pipe joint decreased by 40% to 20MPa and the pulling force decreased by 48.9% without heat-mechanical training. However, after 1 time of thermal-mechanical training, the pressure sealing value of the split-type pipe joint decreased by 12.5% to 32MPa and the pulling force decreased by 21.2% compared with the integral pipe joint. It can be seen that thermal-mechanical training can significantly improve the joint performance of split pipe joints, and the split pipe joint can meet the requirements of medium and low pressure pipeline connection and maintenance.

Study on avalanche breakdown and Poole–Frenkel emission in Al-rich AlGaN grown on single crystal AlN

We demonstrate that theoretical breakdown fields can be realized in practically dislocation free Al-rich AlGaN p-n junctions grown on AlN single crystal substrates. Furthermore, we also demonstrate a leakage current density in AlGaN that is independent of the device area, indicating a bulk leakage phenomenon and not surface or mesa-edge related. Accordingly, we identified the Poole–Frenkel emission from two types of point-defect traps in AlGaN as the primary source of reverse leakage before breakdown. Mg-doped AlGaN exhibited leakage currents due to a shallow trap at ∼0.16 eV in contrast with leakage currents observed in Si-doped AlGaN due to a deep trap at ∼1.8 eV.

A Study on the Development of Coupling Simulation Technique for Predicting Toner Particle Leakage

The distribution environment of printer products creates a lot of shocks. The shock causes a variety of malfunctions in the printer. Among them, toner leakage problem is the most difficult problem to solve. Multiple drop tests were conducted to find some causes of toner leakage. However, there are many limitations because toner particle size is too small. In this study, to overcome these limitations and inefficiency of development process, the new simulation method is introduced. This method is developed for predicting toner leakage, and 1-way coupling analysis technology is used between structural analysis solver(LS-DYNA) and particle analysis solver (Metariver DEM) to make a toner leakage phenomenon visible.

유연 리튬 폴리머 이차전지의 기계적 변형에 따른 성능 및 안전성 평가

Purpose: Flexible lithium-ion batteries have been used as energy sources for wearable and flexible devices. However, their reliability in mechanical stress environments must be guaranteed for them to be stably used in these applications. In this study, the effect of mechanical fatigue on the performance and safety of a lithium polymer battery, which is a flexible lithium-ion battery, was investigated.<BR>Methods: Mechanical fatigue tests were conducted under bending, torsion, and wrinkling (i.e., a combination of bending and torsion) modes at various fatigue rates and strains. The capacity degradation of these fatigued flexible lithium-ion batteries was evaluated using the charge–discharge test. Their safety was assessed using various environmental and electrical misuse tests in accordance with existing standards.<BR>Results: The capacity degradation of all fatigued batteries was greater than that of the undeformed battery. In particular, the torsion and wrinkling stress had a greater effect on capacity degradation. The environmental and electrical misuse tests revealed that leakage, explosion, and ignition phenomena were not caused by mechanical fatigue.<BR>Conclusion: Mechanical fatigue stress can be concluded to be the main factor affecting the performance degradation of flexible lithium-ion batteries. Furthermore, further studies are required to determine the root causes of this significant performance degradation.

Preparation of nanocomposite inner coating for natural gas pipeline

Natural gas is an important energy in China's production and life. In the environment of advocating low-carbon life, natural gas is an important part of low-carbon energy. But what does not match with the demand is that the development technology of natural gas in China is relatively backward, and the most prominent one is the gas leakage phenomenon of natural gas pipeline. The aging and corrosion of natural gas pipelines often lead to more serious safety problems. At present, the main solution is to coat the natural gas pipeline with anti-corrosion materials, but the effect is not satisfactory because of the uneven quality of the materials. In order to solve this problem, the preparation method of nanocomposite inner coating and its application in natural gas pipeline are studied in this paper. Firstly, this paper focuses on the application of nano materials and nano composite materials in the field of anti-corrosion coating, and analyzes the physical benefits of materials. It is considered that the protective mechanism of the nanocomposite anticorrosive coating is mainly through the adhesion of the coating to the metal substrate, the mechanical isolation of the corrosive medium, the formation of passive protective film and electrochemical protection on the metal surface. In order to further analyze the specific effect of nanocomposite coating, the corresponding experimental model is established in this paper. Many comparative experiments including tensile property analysis, particle size analysis, hydrophobic property and DSC were carried out. It can be seen from the experimental data that the nano composite anti-corrosion coating performs well in the experimental test and has good corrosion resistance, but both the tensile property and hydrophobicity are related to the degree of hard segment. According to the comprehensive analysis, the nanocomposite inner coating is suitable for the weather pipeline, which is recommended to be popularized.

Research on Safety Cut-off Technology of Gas Leakage Based on Gas Leak Alarm

Gas is an important energy source for urban development and operation, and it is directly related to the daily lives of urban residents. In order to build a complete gas pipeline network, it is necessary to optimize the energy structure and strengthen the safety of gas use through a variety of technical means. According to data surveys, there is still a widespread phenomenon of gas leakage, threatening the physical and mental safety of the people. For this reason, the gas pipeline construction department can use the alarm device and relevant technical means to cut off the gas leakage in a timely manner to ensure the safe management of gas use.

26.4: A Quantitative Method for L0 Light Leakage Sensitivity of TFT‐LCD Based on JND Energy Ratio

In this paper, a quantitative evaluation method of L0 light leakage sensitivity based on JND energy ratio is established by studying the optical characterization and physical significance of L0 light leakage phenomenon. This method uses continuous quantitative indicators instead of human eye evaluation, which fully improves the accuracy and repeatability, and it can also predict the L0 light leakage level after the test module is assembled into the system set. An optical test system was built to simulate the influence of the system set. The liquid crystal module samples with different glass thickness and different sealant were tested. The test results were consistent with the qualitative judgment results of the human eye after the test module is assembled into tablet PC, and the similar level that the human eye can't be distinguished can be quantitatively distinguished. The repeatability error of the method was only 0.89%.

Simulation Analysis of Magnetic Flux Leakage Detection Damage of Natural Gas Pipelines

Pipeline damage can cause pipeline magnetic flux leakage. By analyzing the phenomenon of magnetic flux leakage, the integrity of the natural gas pipeline can be determined. In order to realize the detection of pipeline performance, this paper analyzes the principle of magnetic flux leakage detection technology, uses COMSOL simulation software to establish a metal pipeline simulation model, and compares the magnetic field distribution curves before and after the pipeline damage through ANSYS software. The simulation results show that the integrity of the pipeline can be effectively detected through the magnetic flux leakage detection and analysis.

Floating Filler (FF) in an Indium Gallium Zinc Oxide (IGZO) Channel Improves the Erase Performance of Vertical Channel NAND Flash with a Cell-on-Peri (COP) Structure

In this study, we developed a V-NAND with an improved IGZO-P type (IP) floating filler (FF) structure based on an IGZO channel verified in previous studies and demonstrated that it has a very fast erase speed through device simulation. The proposed FF structure can supply holes generated through the Gate-Induced Drain Leakage (GIDL) phenomenon in the upper polysilicon string select line (SSL) channel to the IGZO channel through a P-type filler, and the structure proposed by this operation shows a very fast erase speed of 4 μs. A fast erase speed was achieved because the filler adjacent to the IGZO channel, like IP structures in previous studies, functioned as a path through which electrons emitted from the charge storage layer moved easily, rather than simply supplying holes. This assumption was confirmed by assessing the change in electron density of the channel during the erase operation. Next, we investigated the optimum conditions for leakage current reduction through various condition changes of the lower ground select line (GSL) gate in the proposed structure. We confirmed that the leakage current of the proposed structure can be minimized by changing the number of lower GSL gates, changing the length of the GSL channel, and/or changing the work function of the GSL gate material. We obtained a leakage current of 10−17 A when the GSL channel was 480 nm long with six GSL gates, each with a length of 40 nm. The work function of the gates was 4.96 eV.

A novel test setup for determining waterproof performance of rubber gaskets used in tunnel segmental joints: Development and application

In this paper, a novel test setup was proposed to perform mechanical and waterproof tests for rubber gaskets used in tunnel segmental joints. Based on the newly developed setup, it is available to simulate typical joint deformation observed during construction and operation stages, e.g., opening, offset, rotation, and eccentric compression. The components and configurations of the setup were presented in detail. Special treatments were subsequently illustrated for ensuring water pressure loading and rational leakage mode. The setup was applied using test specimens obtained from a rapid rail transit shield tunnel under design. Four groups of gasket mechanical tests and 22 groups of gasket waterproof tests were carried out to evaluate the reliability and functionality of the setup. The load-deformation relationship was adopted to demonstrate gasket-in-groove mechanical behavior, while the factors influencing gasket waterproofness were also considered through analyzing the sealant capacity measured under different conditions. The results show that there exists a close correlation between the mechanical and waterproof performance of gaskets. Deterioration of gasket waterproofness generally occurs due to joint offset. Positive and negative joint rotation leads to the opposite variation trend of sealing performance for gaskets. The water leakage phenomenon observed in tests shows good agreement with the field survey results. The developed test setup and methodology provide novel insights into the waterproof examination of gaskets in complex situations.