Current Propagation Research Articles

High-voltage electrocution myelopathy: A case report and review of the literature

Abstract High-voltage electrocution-induced neurological complications are often associated with dire consequences. The low-resistance neural pathway provides an easy gateway for the current propagation and subsequent injuries. We present a case of electrocution-induced high-cervical myelopathy resulting in quadriparesis with sensorimotor and autonomic involvement with a slow recovery course along with the subsequent imaging and electrophysiological finding suggestive of long-term degeneration of the central corticospinal tracts. On review of prior works of literature, few similar cases are seen with varied postulations of the pathophysiology of the injury. More frequent reporting of such cases, which often go undetected, should be done to increase awareness.

Effect of Different Growing Media on Growth Performance of Liberica Coffee Rootstock

Liberica coffee is a hardy perennial crop grown by smallholders as a monocrop or intercrop with coconut or other fruit trees. The current propagation method of Liberica coffee clones is based on grafting, which requires 7-8 months for rootstock to mature and another 7-8 months for planting. The current production manual suggests using a 1:1 ratio of soil to sand to produce matured Liberica coffee rootstock. Studies have shown that using a combination of planting media, such as rice husk charcoal and compost, can result in higher plant height, number of leaves, internodes, and leaf area. A combination of leaf manure, silt, straw, peat moss, and soil performed better than 100% soil due to better nutrients, water, and anchorage provision. Consequently, a study to assess the impacts of growing media on MKL 1 polyhybrid as rootstock was carried out. The experimental design used was Randomized Complete Block Design (RCBD) with 4 replications. Treatment consist of T1 = soil + sand (1:1), T2 = soil + cocopeat (1:1), T3 = soil + peat moss + sand + cocopeat (1:1:1:1), T4 = soil + peat moss + cocopeat (2:1:1), T5 = soil + peat moss (3:1), T6 = soil + chicken manure (3:1) and T7 = soil + CIRP (10:1). Parameters evaluated in this study include plant height, leaves number, stem girth, SPAD, fresh root weight and dried root weight. The findings indicate that the treatments had a significant impact on girth, SPAD, and root fresh weight and these three parameters share significant positive association with one another. Girth performed best under T4 although fresh root weight and SPAD performed noticeably better under T3. Current recommended protocol for media performed significantly lower compared to other media. This study offers a new outlook on how to improve current protocol on Liberica coffee rootstock preparations.

Analysis of Harmonic Current Propagation in Industrial Sectorin Function of the Load Level

This article presents the influence of the loadlevel variation in the power quality. The study it is based on apunctual audit, made to a group of loads in a cement industry,with experimental data acquired by monitoring equipment.Quality indexes of Power Energy Industrial System aredetermined for different points of the network, such as points ofcommon coupling, disturbing load points, linear load points andreactive energy compensation points. The monitored data areanalyzed, according to the patterns of the IEEE 519-1992standard. Using audit results along with system data, a PowerEnergy Industrial System simulation model is developed inMATLAB®/SIMULINK®. This model is then used to extrapolatethe Harmonic Distortion Propagation at the industry plant, forother load levels apart from the monitored ones. Theinformation related to Harmonic Distortion Propagation fordifferent load levels is used to strengthen the conclusions ofPower Energy Industrial System audits.

A hybrid modeling method of fatigue crack growth for gas turbine blades under combined high and low cycle fatigue loadings

Fatigue crack is one of the major faults of the gas turbine blades. Previous modeling studies on fatigue crack growth of blades mainly focus on a single numerical or analytical approach considering different sizes of cracks under various fatigue loadings. However, the actual crack propagation process is time-varying. The iteration and update of the model are necessary to evaluate the fatigue life of blades precisely. This paper proposes a hybrid modeling method to study blade crack growth under combined high and low cycle fatigue (CCF) loadings. The method emphasizes the combination and interaction between the finite element (FE) numerical simulation and the analytical calculation based on the fracture mechanics model. The current crack propagation length of the blade FE model is calculated from the crack growth rate obtained by the stress intensity factor (SIF) range according to Paris law. Then, a new SIF range is resolved from the FE model with the updated crack length. The proposed method is verified by the first-stage compressor blade from an in-service gas turbine. Results show that the crack growth is faster using the proposed hybrid modeling method than the traditional method. The update of the SIF range under CCF loadings cannot be ignored when predicting the fatigue life of the blade. Also, a sensitivity analysis is carried out. Suggestions are given on how to set the crack extension length at each stage during modeling, especially when the blade approaches failure.

“Let’s Propagate the Dharma”: A Critical Survey of the Activities of the Jogye Order of Korean Buddhism’s Seventh Dharma Propagation Bureau

The Jogye Order has been facing a deepening crisis since the turn of the millennium. The rapid decline in membership had been compounded by a growing loss of confidence in the order’s monastic leadership following a succession of scandals in the 1990s and 2010s involving sectarian infighting and high-level corruption. While the practice of “Dharma propagation” (pogyo) has been critical to Korean Buddhism’s revival over the twentieth century, the Jogye Order’s steadily worsening membership crisis has revitalized institutional interest in Dharma propagation. With the independent establishment of its “Dharma Propagation Bureau” (Pogyowon) in 1994, the order has steadily increased its financial and practical support of a diversity of propagation efforts as, over recent decades, the order knows that its long-term survival might very well depend on these efforts’ success. Given the crucial nature of the Jogye Order’s current propagation efforts, this article will conduct a critical examination of the recent history of the JO’s Dharma Propagation Bureau, with a particular focus on the Bureau’s activities under its seventh director, Ven. Jihong (in office 2016 through 2021).

Micropropagation of Duboisia Species via Shoot Tip Meristem

Duboisia is an Australian native, commercially valuable for tropane alkaloid extraction. Clonal propagation of elite selections is essential to establish highly productive plantations. The current propagation system using stem cuttings is proven to be inefficient, prompting the industry to seek a more efficient and effective propagation tool. Tissue culture is a cost-effective alternative for mass propagation of true-to-type plants, particularly ideal for propagating elite Duboisia selections. In this context, attempts were made to develop a commercially viable high throughput micropropagation system for three Duboisia species: Duboisia myoporoides, Duboisia leichhradtii and Duboisia hopwoodii. Various nutrient media, hormone combinations and incubating conditions were tested to optimise each stage of the micropropagation pipeline. The findings revealed that the tissue culture media composition and hormone requirements are species-specific. With the optimised conditions, an efficient tissue culture system was developed, achieving successful meristem induction and multiplication. Species-specific rooting protocol optimisation resulted in 100% rooting for D. myoporoides and D. leichhardtii, and 70% rooting for D. hopwoodii. Furthermore, an optimised acclimatisation protocol supported 100% survival of D. myoporoides and D. leichhardtii and 80% of D. hopwoodii plantlets. This study, for the first time, demonstrated the capacity of successful meristem culture of three Duboisia species, establishing the foundation for high throughput micropropagation of Duboisia species.

Review on 6G-oriented terahertz communication channel

With the large-scale commercialization of 5G mobile communication systems in the world, 6G technology is becoming a new hotspot of global information technology research. The terahertz band (300GHz to 3THz) has extremely rich frequency resources, which can support ultra-high speed wireless communication from 100Gbps to 1Tbps, improve the existing 5G peak transmission rate by one or two orders of magnitude, and meet the requirements of new applications such as ultra-high resolution holographic communication and meta-universe. An in-depth understanding of the propagation channel is crucial to the design of the communication system. This paper summarizes the research status of the terahertz channel, including its characteristics in the atmosphere, the current channel propagation model, and terahertz channel measurement. At the same time, the future research direction of terahertz communication is analyzed and prospected, and the possible challenges in the future research are discussed, which will help promote the application of terahertz communication technology to 6G communication. Due to technical limitations, terahertz channels have not been fully developed and utilized in the field of communication, and there are many technical bottlenecks that cannot be broken. In the future, new channel models may be built, and there will be opportunities for AI-assisted channel measurement.

Melt dynamics with MEMENTO — Code development and numerical benchmarks

The new numerical implementation of the MEMOS-U physics model, fully validated in multiple EUROfusion sponsored experiments, is presented. The computational tool - MEMENTO (MEtallic Melt Evolution in Next-step TOkamaks)- is able to address fusion-relevant melting scenarios that feature complex plasma-facing component geometries, involve intricate plasma wetting patterns and are characterized by vast spatio-temporal scale separations. The high level architecture of the code is discussed and numerical benchmarks of the heat transfer, fluid dynamics and current propagation solvers are presented.

Scalable angular spectrum propagation

Coherent field propagation is an essential computational tool in optics with applications ranging from computational optics and optical design to iterative field reconstructions. An improvement in the computational speed of current propagation methods is therefore highly desired. We describe a scalable angular spectrum (SAS) algorithm with zoom capability for numerical propagation of scalar wave fields in homogeneous media. It allows for propagation models where the destination pixel pitch is larger than the source pixel pitch, requires a computational complexity proportional to the cost of three successive fast Fourier transform operations of the input field, and it is valid for high numerical aperture (NA) propagation geometries. We find that SAS propagation approaches the precision of the computationally far more expensive angular spectrum method in conjunction with zero-padding. This was computationally confirmed by propagation examples. Finally, we discuss the validity of the proposed SAS method, derive practical bandlimit criteria, and state a limit for the propagation distance. The scalability, efficiency, and accuracy at high NA of our proposed wave propagation algorithm yield benefits for a large variety of forward and inverse modeling problems with the ability to apply automatic differentiation.

Slumping regime in lock-release turbidity currents

Most gravitational currents occur on sloping topographies, often in the presence of particles that can settle during the current propagation. Yet an exhaustive exploration of associated parameters in experimental studies is still lacking. Here, we present an extensive experimental investigation of the slumping regime of turbidity (particle-laden) currents in two lock-release (dam-break) systems with inclined bottoms. We identify three regimes controlled by the ratio between settling and current inertia. (i) For negligible settling, the turbidity current morphodynamics corresponds to that of saline homogeneous gravity currents, in terms of velocity, slumping (constant-velocity) regime duration and current morphology. (ii) For intermediate settling, the slumping regime duration decreases to become fully controlled by a particle settling characteristic time. (iii) When settling overcomes the current initial inertia, the slumping (constant-velocity) regime is no longer detected. In the first two regimes, the current velocity increases with the bottom slope, of approximately$35\,\%$between$0^\circ$and$15^\circ$. Finally, our experiments show that the current propagates during the slumping regime with the same shape in the frame of the moving front. Strikingly, the current head is found to be independent of all experimental parameters covered in the present study. We also quantify water entrainment coefficients$E$and compare them with previous literature, hence finding that$E$increases rather linearly with the current Reynolds number.

Morphological Modelling to Investigate the Role of External Sediment Sources and Wind and Wave-Induced Flow on Sand Bank Sustainability: An Arklow Bank Case Study

Offshore anthropogenic activities such as the installation of Offshore Renewable Energy (ORE) developments and sediment extraction for marine aggregates have been shown to disrupt current flow, wave propagation, and sediment transport pathways, leading to potential environmental instability. Due to the complexity of the interconnected sediment transport pathways in the south-western Irish Sea combined with an increase in planned anthropogenic activities, the assessment of this risk is imperative for the development of a robust marine spatial plan. Subsequently, this study uses two-dimensional morphological modelling to build upon previous studies to assess the dependency of Arklow Bank’s local sediment transport regime on external sediment sources. Additionally, scenario modelling is used to identify vulnerable areas of this offshore linear sand bank to wind and wave-forcing and to examine the nature of this impact. A sediment budget is estimated for Arklow Bank, whereby seven source and nine sink pathways are identified. New evidence to support the exchange of sediment between offshore sand banks and offshore independent sand wave fields is also provided. The areas of the bank most vulnerable to changes in external sediment sources and the addition of wind- and wave-induced flow are analogous. These high vulnerability zones (HVZs) align with regions of residual cross-flow under pure current conditions. The restriction of sediment sources off the southern extent of Arklow Bank impacts erosion and accretion patterns in the mid- and northern sections of the bank after just one lunar month of simulation. Where tidal current is the primary driver of sand bank morphodynamics, wind- and wave-induced flow is shown to temporarily alter sediment distribution patterns. Wind and wave-induced flow can both accelerate and decelerate the east-west fluctuation of the upper slopes of the bank, yet the nature of this impact is inconsistent due to the misalignment of the directionality of these two forces. The methods and new knowledge derived from this study are directly applicable to tidally-dominated environments outside the Irish Sea.

Analytical model and numerical simulation of relief well adjacent distance considering multi-layer media

Accurate measurement of adjacent well distance (AWD) is the key factor restricting the successful plugging of relief well (RW). Traditional ranging technology can't meet the accuracy requirements of AWD. Fortunately, magnetic ranging technology has shown great superiority in this respect. However, the magnetic ranging algorithm based on low-frequency injected current has always been a difficult problem. Therefore, based on the magnetic ranging principle of low frequency injection current, the propagation law of current in medium is revealed. Considering the effect of mud on current propagation, a multilayer medium model is established to improve the calculation accuracy of current intensity in adjacent casing. Through numerical simulation and experimental comparison, the validity of the analytical model is verified. Analysis results show that the intensity of injected current, the conductivity of medium and the distance between electrode and casing axis have a significant effect on the current of the casing. The radial electric field intensity fluctuates obviously on the interface of the medium. When the distance from the electrode to the casing axis is constant, the magnetic field strength of the measuring point is also affected by the distance from the electrode to the probe pipe and the relative inclination angle. According to the distance between the electrode and the axis of the casing, the optimal distance between the electrode and the probe tube can be obtained, so that the magnetic induction intensity of the measuring point is maximized. The results show that the multi-layer medium model is more suitable for the actual working conditions and the calculation error is minimal.

Negative frequencies in pulse propagation equations and the double analytic signal

In recent years, the topic of negative frequencies has resurfaced in optics motivated by the optical analogue of Hawking radiation. We discuss the physical meaning of negative frequencies and the conditions under which they are relevant. We review how negative frequencies are treated in current pulse propagation models based on the electric field (EF) and the analytic signal (AS). We focus on experimentally measured signals predicted by the conservation of negative comoving frequency in the nonlinear polarization terms to advance these concepts. We propose a new formalism called the double analytic signal (DAS) which clearly separates negative frequencies from positive ones. Additionally, we reduce this new formalism to the AS to prove their equivalence. Throughout the paper, we present numerical solutions of the unidirectional pulse propagation equation to illustrate the EF, AS, and DAS formalisms and to highlight their differences.

Intelligent Interactive Deformable Image Registration for Online Adaptive Radiotherapy.

The goal of this study is to streamline the time-consuming contouring process in online adaptive radiotherapy (ART) by utilizing a deep learning-based interactive deformable image registration (DIR) algorithm. The objective is to minimize manual review and editing of automatically generated initial contours of organs-at-risk (OARs) and targets, thereby improving the efficiency and effectiveness of the treatment process. Our proposed method reforms the current DIR-based contour propagation method in clinical practice through the implementation of a deep learning-based interactive approach. The steps include: 1) generation of an initial deformable vector field (DVF) using a DL model, based on fixed and moving image pairs, resulting in the initial contours of OARs and targets; 2) clinician review/edit one the OAR/target contours as needed; 3) updated contour is sent to DL model to update the DVF and the remaining OARs/targets contours. Repeat this process until satisfactory contour qualities are achieved. We used the Open Access Series of Imaging Studies (OASIS) as the testbed, including 394 (train) and 20 (test) brain T1-weighted MRI scans, each containing 35 annotated organs. The U-Net architecture was employed to update the DVF from fixed/moving images, initial contours, and updated contours. We compared our approach to traditional manual editing without interaction and quantified the effort reduction using the added path length (APL) metric which is supposed to be proportional to the absolute time spent on the contour editing. We conducted paired t-test to show the significance. For comparison purpose, we assumed the clinicians edit the contours with the largest APL, i.e., the contours that require the most editing efforts. The editing effort, as measured by APL, was reduced by 18.5% to 25.4% with a mean of 23.3%, median of 23.6%, and standard deviation of 1.9%. The significance of the results was confirmed with a p-value of 1.47e-24. Our study demonstrates a significant reduction in editing effort, as measured by APL, compared to traditional manual contour editing. These results demonstrate the potential of our deep learning-based interactive approach to improve the efficiency and accuracy of the contouring process in clinical practice.

Hybrid improved whales and sine cosine optimization algorithms for the optimal configuration of distribution networks in the presence of dispersed generation systems before, during, and after short circuit current propagation case study: overhead and underground networks in the laghouat region of Algeria

Hybrid improved whales and sine cosine optimization algorithms for the optimal configuration of distribution networks in the presence of dispersed generation systems before, during, and after short circuit current propagation case study: overhead and underground networks in the laghouat region of Algeria

Long-chain propagation pathways from meteorological to hydrological, agricultural and groundwater drought and their dynamics in China

Drought propagation is a complex process involving various components of water cycle. Clarifying the propagation pathways and mechanisms among multiple types of droughts is essential. However, the current drought propagation analysis mainly focuses on the relationship between two types of droughts, which highlights the urgence in studying the propagation among multiple types of droughts. To this end, this study will first develop a dynamic threshold framework to identify the propagation pathways among meteorological, hydrological, agricultural and groundwater droughts, and further investigate the risk probability, trigger threshold and their controlling factors in the long-chain drought propagation. The propagation pathways among multi-type droughts were identified as meteorological-hydrological-agricultural-groundwater drought. In the long-chain drought propagation, the spatial heterogeneity of risk probability and trigger threshold in China is significant. Among them, the risk probability triggering the next stage decreases progressively in south China, and the drought propagation is blocked. A significant upward trend exhibited in the trigger thresholds in east China, indicating that drought resistance is weakening. Temperature, aridity index and soil evaporation flux are the main drivers affecting the dynamics of trigger thresholds. This study contributes to the completeness and systematization of the propagation process of drought in the water cycle. It not only offers new insights into the process of drought propagation, but also provides scientific guidance for establishing drought early warning systems and reducing drought hazards.

Advanced condition-based monitoring of CFRP under multiple impacts using monte carlo based prognostics and real-time self-sensing data

Studies on self-sensing system under multiple impacts are limited. Furthermore, real-time prognostics research using electromechanical behavior for impact-damage growth is rare and the impact-damaged area analysis has limited in self-sensing. In this paper, the health state of the carbon-fiber-reinforced plastic samples were monitored in real time utilizing self-sensing data. In-depth damage analysis using C-scan and cross-sectional analysis were conducted to investigate the correlation between the electromechanical behavior analysis. Moreover, the relationship between electromechanical behavior and the impact-damaged area was investigated. The damage propagation during multiple impacts was identified in real time. Furthermore, the electromechanical behavior was predicted to prognosticate the damage propagation in the samples under multiple impacts using a particle filter. The impact damage area was determined based on the predicted electromechanical behavior. Moreover, the prediction accuracy according to data acquired was investigated. An advanced condition-based monitoring methodology can monitor current and future health states and damage propagation under multiple impacts that overcomes the previous self-sensing research. Therefore, this study showed high applicability and guidelines for future self-sensing research fields.

A two-dimensional double layer-averaged model of hyperconcentrated turbidity currents with non-Newtonian rheology

Hyperconcentrated turbidity currents typically display non-Newtonian characteristics that influence sediment transport and morphological evolution in alluvial rivers. However, hydro-sediment-morphological processes involving hyperconcentrated turbidity currents are poorly understood, with little known about the effect of the non-Newtonian rheology. The current paper extends a recent two-dimensional double layer-averaged model to incorporate non-Newtonian constitutive relations. The extended model is benchmarked against experimental and numerical data for cases including subaerial mud flow, subaqueous debris flow, and reservoir turbidity currents. The computational results agree well with observations for the subaerial mud flow and independent numerical simulations of subaqueous debris flow. Differences between the non-Newtonian and Newtonian model results become more pronounced in terms of propagation distance and sediment transport rate as sediment concentration increases. The model is then applied to turbidity currents in the Guxian Reservoir planned for middle Yellow River, China, which connects to a tributary featuring hyperconcentrated sediment-laden flow. The non-Newtonian model predicts slower propagation of turbidity currents and more significant bed aggradation at the confluence between the tributary Wuding River and the Yellow River in the reservoir than its Newtonian counterpart. This difference in model performance could be of considerable importance when optimizing reservoir operation schemes.

Characterising small objects in the regime between the eddy current model and wave propagation

AbstractBeing able to characterise objects at low frequencies, but in situations where the modelling error in the eddy current approximation of the Maxwell system becomes large, is important for improving current metal detection technologies. Importantly, the modelling error becomes large as the frequency increases, but the accuracy of the eddy current model also depends on the object topology and on its materials, with the error being much larger for certain geometries compared to others of the same size and materials. Additionally, the eddy current model breaks down at much smaller frequencies for highly magnetic conducting materials compared to non-permeable objects (with similar conductivities, sizes and shapes) and, hence, characterising small magnetic objects made of permeable materials using the eddy current at typical frequencies of operation for a metal detector is not always possible. To address this, we derive a new asymptotic expansion for permeable highly conducting objects that is valid for small objects and holds not only for frequencies where the eddy current model is valid but also for situations where the eddy current modelling error becomes large and applying the eddy approximation would be invalid. The leading-order term we derive leads to new forms of object characterisations in terms of polarizability tensor object descriptions where the coefficients can be obtained from solving vectorial transmission problems. We expect these new characterisations to be important when considering objects at greater stand-off distance from the coils, which is important for safety critical applications, such as the identification of landmines, unexploded ordnance and concealed weapons. We also expect our results to be important when characterising artefacts of archaeological and forensic significance at greater depths than the eddy current model allows and to have further applications parking sensors and improving the detection of hidden, out-of-sight, metallic objects.

Graph Convolutional-Based Deep Residual Modeling for Rumor Detection on Social Media

The popularity and development of social media have made it more and more convenient to spread rumors, and it has become especially important to detect rumors in massive amounts of information. Most of the traditional rumor detection methods use the rumor content or propagation structure to mine rumor characteristics, ignoring the fusion characteristics of the content and structure and their interaction. Therefore, a novel rumor detection method based on heterogeneous convolutional networks is proposed. First, this paper constructs a heterogeneous map that combines both the rumor content and propagation structure to explore their interaction during rumor propagation and obtain a rumor representation. On this basis, this paper uses a deep residual graph convolutional neural network to construct the content and structure interaction information of the current network propagation model. Finally, this paper uses the Twitter15 and Twitter16 datasets to verify the proposed method. Experimental results show that the proposed method has higher detection accuracy compared to the traditional rumor detection method.