Anode Position Research Articles

S2−-modified hetero MOF-on-MOF of Ni-MOF/Fe-MOF with efficient seawater oxidation performance

Direct seawater electrolysis offers a viable solution to the excessive consumption of fresh water resources in existing industrial electrolytic water processes. However, electrolysis efficiency and material stability are affected by electrode material corrosion caused by chlorine evolution reactions (CER) at the anode positions. In this study, the prepared S-Ni-MOF/Fe-MOF material exhibits an exceptional performance in the oxygen evolution reaction (OER) both in alkaline solution and seawater. Specifically, the material achieves low overpotentials of 281 and 279 mV in 1.0 M KOH and alkaline seawater at 100 mA cm−2 current density, and maintains stability for at least 100 h in both electrolyte solutions. The electronic structure of MOF-on-MOF was modulated through the introduction of S2−, which induced a large number of vacancies. Furthermore, the reconstruction process on the material surface was accelerated by the formation of NiOOH and FeOOH, that served as protective layers and prevented the corrosion of the electrode material by Cl−, thereby enhancing its stability in seawater. Furthermore, computational studies have indicated that the Fe-Ni active sites at the heterointerface exhibit a synergistic effect, which has been confirmed by density functional theory (DFT) calculations. These results prove that this combination significantly reduces the energy barrier associated with the OER. Consequently, the reaction process is accelerated.

Systematic Study of the Effect of Cycle Number and Crystal Structure on Si Anodes

AbstractThis paper shows that the number of cycles and the crystal structure play an important role in the capacity and cycling ability of lithium‐ion batteries. However, the detailed dynamics and continuity of the capacity decay mechanism caused by the number of cycles and crystal structure need to be further understood at the nanoscale. Molecular dynamics simulation was used to examine the microstructure development and deformation behavior of the Si anode in an electric field. The results show that the increase of the number of cycles leads to a large expansion of the volume of the Si electrode, which further leads to the loss of capacity and the decrease of cycle capacity, as well as the decrease of structural stability. The formation of Si crystal structure from diamond structure to amorphous depends on the depth of lithiation and desulfurization. Due to the presence of a large number of nanoscale voids, the Si anode has undergone volume expansion. The transformation associated with nanogap nucleation caused by the involuntary diffusion process is driven by more cycles, resulting in irreversible capacity loss of lithium‐ion batteries. The analysis model shows that the stress caused by diffusion is not only related to the position of the Si anode, but also to the cycle time.

Good moments to stimulate the brain – A randomized controlled double-blinded study on anodal transcranial direct current stimulation of the ventromedial prefrontal cortex on two different time points in a two-day fear conditioning paradigm

It is assumed that extinction learning is a suitable model for understanding the mechanisms underlying exposure therapy. Furthermore, there is evidence that non-invasive brain stimulation (NIBS) can elevate extinction learning by enhancing frontal brain activity and therefore NIBS can augment symptom reduction during exposure therapy in phobias. But, the underlying processes are still not well established. Open questions arise from NIBS time points and electrode placement, among others. Therefore, we investigated in a 2-day fear conditioning experiment, whether anodal transcranial direct current stimulation (tDCS) of the ventromedial prefrontal cortex (vmPFC) modulates either fear memory consolidation or dampened fear reaction during fear extinction. Sixty-six healthy participants were randomly assigned either to a group that received tDCS after fear acquisition (and before fear memory consolidation), to a group that received tDCS directly before fear extinction, or to a control group that never received active stimulation (sham). Differential skin conductance response (SCR) to CS+ vs. CS- was significantly decreased in both tDCS-groups compared to sham group. Our region of interest, the vmPFC, was stimulated best focally with a lateral anode position and a cathode on the contralateral side. But this comes along with a slightly lateral stimulation of vmPFC depending on whether anode is placed left or right. To avoid unintended effects of stimulated sides the two electrode montages (anode left or right) were mirror-inverted which led to differential effects in SCR and electrocortical (mainly late positive potential [LPP]) data in our exploratory analyses. Results indicated that tDCS-timing is relevant for fear reactions via disturbed fear memory consolidation as well as fear expression, and this depends on whether vmPFC is stimulated with either left- or right-sided anode electrode montage. Electrocortical data can shed more light on the underlying neural correlates and exaggerated LPP seems to be associated with disturbed fear memory consolidation and dampened SCR to CS+ vs. CS-, but solely in the right anode electrode montage. Further open questions addressing where and when to stimulate the prefrontal brain in the course of augmenting fear extinction are raised.

WIRELESS SENSOR NETWORK LOCALIZATION TECHNIQUES PERFORMANCE

A large number of inexpensive, small sensors make up a wireless sensor network. The collection and transmission of data is one of the crucial functions of a sensor network. In the greater part of the applications, it is of much interest to figure out the area of the information. Localization methods can be used to obtain this kind of information. Therefore, node localization is very important when using localization algorithms to determine the position of a node. As a result, WSN node localization emerges as one of the primary obstacles. The localization schemes can be broadly divided into two groups based on range measurements, such as: range based and range free plans. Range-based localization techniques cannot be used due to the sensing node's hardware limitations and high cost. Since coarse accuracy is sufficient for most sensor network applications, range-free schemes are being considered an alternative. The performances and accuracy of the range-free algorithms were tested with the application of MATLAB 2017a. The results demonstrated that the amorphous algorithm has the lowest localization error in most cases in comparison to the performance of these four algorithms. Likewise, results demonstrated amorphous, and DV-hop algorithms have 100% coverage rate in every situation that were tested.

Development of the Galvanic Anode Performance Test for Assessing the Longevity of Galvanic Anodes for Reinforced Concrete Structures

The NACE impact report (2016) states that nearly 50% of reinforced concrete (RC) structures experience major repair in about 10 y. The existing approach of patch repair does not address the root cause and may not be durable—resulting in re-repair and huge economic loss. Galvanic anodes (GAs) are gaining widespread acceptance to achieve maintenance-free repair life for a few decades. However, a few GAs with inadequate characteristics are prematurely failing (within a few months). There are no short-term test methods to evaluate the longevity of GAs. Therefore, this work focuses on developing a short-term test method (galvanic anode performance [GAP] test) to assess the longevity of GAs. For this, the GAP specimen was designed by simulating RC structures protected with cathodic protection systems as follows: (i) GA embedded in bedding mortar (i.e., anode), (ii) nichrome mesh (i.e., cathode simulating rebars in RC structures), (iii) position of anode and cathode, (iv) application of potential difference (0.5 V, 1 V, 5 V, 10 V, 20 V, and 30 V) to accelerate the degradation of GAs, and (v) electrolyte to simulate conductivity of concrete. Applied potentials >5 V could not capture the difference in characteristics of GAs. However, potential differences of 0.5 V, 1 V, and 5 V could show the true behavior of GAs in various exposure conditions. Then, an approach is proposed to evaluate the service life of GAs. Possible reasons for the premature failure of anodes were investigated by evaluating pH and pore volume of encapsulating mortar. The GAP test can help practicing engineers estimate the longevity of GAs.

A modified GNN architecture with enhanced aggregator and Message Passing Functions

Graph neural networks (GNN) uphold the essence of irregularly structured information embedded in a graph via message passing among the nodes and aggregating the node features at various levels of the graph. In the past, researchers have extensively used the GNN models for several semi-supervised node classification tasks. Existing GNN models do not use nodes’ information sufficiently. The use of inter-node feature-level correlational information with the existing GNN models might lead to more powerful learning models. Here, a weighting scheme has been developed for message passing and aggregation functions. This model has been named “Vector GNN”, or in short, “VecGNN”, due to its relationship with vector space. VecGNN takes into consideration the relative position of a node with respect to its neighboring nodes in the feature space, which influences the weight of features passed to the information aggregation phase. These weights are assigned using two different statistical measures: Jaccard’s coefficient and Cosine similarity. The proposed weighting scheme uses a generalized approach that can be easily incorporated into several GNN frameworks. VecGNN is evaluated using three citation datasets: Citeseer, Pubmed, and Cora. On these datasets, three sets of experiments have been conducted with varying numbers of training and testing nodes. We have used training, validation, and test set nodes with ratios of 1:1:8, 2:1:7, and 3:1:6. Experimenting on these, we observe an improvement of 2%–4% over the baseline models: Graph Convolution Network (GCN), Graph Attention Network (GAT), and Jumping Knowledge Networks (JKNets). The source code is available at the link https://github.com/sourodeeproy/VecGNN.

Axiomatic characterization of PageRank

This paper examines the fundamental problem of identifying the most important nodes in a network. To date, more than a hundred centrality measures have been proposed, each evaluating the position of a node in a network from a different perspective. Our work focuses on PageRank which is one of the most important centrality measures in computer science used in a wide range of scientific applications. To build a theoretical foundation for choosing (or rejecting) PageRank in a specific setting, we propose to use an axiomatic approach. Specifically, we propose six simple properties and prove that PageRank is the only centrality measure that satisfies all of them. In this way, we provide the first axiomatic characterization of PageRank in its general form.

Evaluation of the effect of sacrificial anodes on the drag coefficient of tubular elements due to marine currents

The structural design of fixed offshore platforms is mainly based on characterizing inertial and drag loads due to waves, currents, and wind. These structures incorporate sacrificial anodes as corrosion protection systems. The sacrificial anodes increase the exposed area of the tubular elements of the jacket. Therefore, designers need to determine hydrodynamic coefficients for tubular elements with anodes to calculate the load increment due the anodes. This work focuses on evaluating the effects of anodes on the drag coefficients for tubular elements, considering current velocities from 0.25 m/s to 2 m/s, in 0.25 m/s increments, tubular element diameters from 0.508 m to 3.048 m, in 0.508 m increments, and three different positions of the anode, back (P1), front (P2), and lateral (P3) to the tubular element, concerning the direction of the current. This work uses CFD analysis, considering RANS and the k-ω model. The results show that the drag coefficient can be calculated as a function of the tubular element's diameter and the anode's position. Correlations were obtained for calculating an equivalent drag coefficient or an equivalent hydrodynamic diameter for any position of the anode as a function of a diameter ratio and the angle of its position in the tubular element concerning the flow direction.

Investigation of electrochemical properties, leachate purification, organic matter characteristics, and microbial diversity in a sludge treatment wetland- microbial fuel cell

Sludge treatment wetland-microbial fuel cell (STW-MFC) is a unique sludge treatment process that produces bioelectricity, but its technology is still in its infancy. This study investigated the electrochemical properties, organic matter characteristics, leachate purification, and microbial community structure of STW-MFCs as affected by electrode location. When electrodes were placed in the filler layer, the STW-MFC system presented a higher power generation capacity (maximum output power density: 0.498 W/m3; peak cell voltage: 0.879 V) and organic matter degradation efficiency. The hydrophilic fraction was the main dissolved organic carbon fraction in sludge extracellular biological organic matter (EBOM) and leachate dissolved organic matter (DOM). Aromatics were mainly concentrated in the hydrophobic acid fraction. The UV-254 content of sludge EBOM decreased mainly in the hydrophilic and transphilic acid fractions. The excitation-emission matrix analysis showed that tryptophan-like protein was more easily eliminated than tyrosine-like protein. In addition, there was a strong correlation between voltage and NH4+ removal efficiency; a negative correlation between total chemical oxygen demand (TCOD), total nitrogen (TN), and total phosphorus (TP) removal efficiency, and a negative correlation between pH and TN, TP, and NH4+ removal efficiencies. High-throughput sequencing showed that the system was most abundant in Thermomonas, Geothrix and Geobacter when the electrodes were placed in the filled layer, while the levels of genes for membrane transport, carbohydrate metabolism and energy metabolism functions were higher than in other systems. This work will support STW- MFC widespread implementation by illuminating the underlying mechanics of different anode positions.

Experimental and numerical simulation study of the effect for the anode positions on the discharge characteristics of 300 W class low power Hall thrusters

Low-power Hall thruster (LHT) generally has poor discharge efficiency characteristics due to the large surface-to-volume ratio. Aiming to further refine and improve the performance of 300 W class LHT in terms of thrust and efficiency, and to obtain the most optimal operating point, the experimental study of the discharge characteristics for three different anode positions was conducted under the operation of various discharge voltages (100–400 V) and anode mass flow rates (0.65 mg·s−1 and 0.95 mg·s−1). The experimental results indicated that the thruster has the most excellent performance in terms of thrust and efficiency etc at a channel length of 27 mm for identical operating conditions. In addition, particle in cell simulations, employed to reveal the underlying physical mechanisms, show that the ionization and acceleration zone is pushed downwards towards the channel exit as the anode moves towards the exit. At the identical operating point, when the channel length is reduced from 32 to 27 mm, the ionization and acceleration zone moves towards the exit, and the parameters such as thrust and efficiency increase due to the high ionization rate, ion number density, and axial electric field. When the channel length is further moved to 24 mm, the parameters in terms of thrust (F) and efficiency ( ηa ) are reduced as a result of the decreasing ionization efficiency ( ηm ) and the larger plume divergence angle ( α ). In this paper, the results indicated that an optimum anode position ( ΔL=27 mm) exists for the optimum performance.

The Effects of Different Anode Positions on the Electrical Properties of Square-Silicon Drift Detector.

The Silicon Drift Detector (SDD) with square structure is often used in pixel-type SDD arrays to reduce the dead region considerably and to improve the detector performance significantly. Usually, the anode is located in the center of the active region of the SDD with square structure (square-SDD), but the different anode positions in the square-SDD active area are also allowed. In order to explore the effect on device performance when the anode is located at different positions in the square-SDD active region, we designed two different types of square-SDD in this work, where the anode is located either in the center (SDD-1) or at the edge (SDD-2) of its active region. The simulation results of current density and potential distribution show that SDD-1 and SDD-2 have both formed a good electron drift path to make the anode collect electrons. The experimental results of device performance at the temperature range from −60 °C to 60 °C show that the anode current of the two fabricated SDDs both decreased with the decrease of temperature, but their voltage divider characteristics exhibited high stability resistance value and low temperature coefficient, thereby indicating that they could both provide corresponding continuous and uniform electric field at different temperatures. Finally, SDD-1 and SDD-2 have energy resolutions of 248 and 257 eV corresponding to the 5.9 keV photon peak of the Fe-55 radioactive source, respectively. Our experimental results demonstrate that there is no significant impact on the device performance irrespective of the anode positions in the square-SDD devices.

Geometry optimization of an electrochemical reactor for bleaching kaolin

AbstractHigh-whiteness kaolinite mining reserves are scarce. In some locations, it is necessary to remove material to access them (adding to the cost). Therefore, processes have been developed to eliminate contaminants, such as iron, and provide alternatives to the used contaminated materials that, after being treated, meet quality criteria. In our previous research, we developed an electrochemical process for kaolin whitening at the laboratory level and bench scale, demonstrating the reaction mechanisms that occur during the removal of iron from kaolin. However, the geometry used at the laboratory level does not present the most suitable position for the electrodes. Therefore, in the present study, we focused on the geometry and the function of the electrodes. This is necessary during the escalation process to reach the pilot-scale level. The study was carried out using computer-aided engineering in the COMSOL Multiphysics computer program and by analysing the distribution of the electric potential and the electric current of the geometries considered while performing the scaling. The results indicated that the change in the anode position from perpendicular to parallel to the discs improved the distribution of electric current density on the cathode surface and so increased the elimination of iron through electrochemical deposition. Similarly, to reduce the amount of material used in the construction of the reactor, the anode-size effect was analysed, revealing that relatively small anodes improved the distribution of electric current density over the entire surface of the electrode and not only at the edges.

Optimization Of Wsn Deployment Using Pso Algorithm For Forest Fire Detection

Abstract
 Forest fires are disasters that have often occurred in recent years. This has a huge impact on both the environment and society itself. Delayed handling of fires is one of the triggering factors for the large losses caused by the disaster. The use of a Wireless Sensor Network is one solution so that information related to fires is conveyed to the authorities quickly so that the handling can be done more quickly. In this study, a simulation was made to determine the optimal position of a node to detect fires optimally. This simulation is run on NS3 Software on Ubuntu 18.04 Linux Operating System. In the optimization process, the PSO algorithm is run with Google Colab. The results of each iteration on the PSO will be simulated in NS3 and the communication between nodes will be seen. There are 12 iterations of the maximum 30 iterations specified, and there are 12 simulations according to the number of iterations. From 12 simulations that have been carried out, it is known that in the last iteration of the 10 nodes installed, all nodes communicate. Communication between nodes can be seen through .pcap files and graphs on NetAnim, the communication is characterized by sending fire messages to each installed node. In the last iteration, 10 nodes received a fire message.
 Keywords: Wireless Sensor Network, Forest fires, Particle swarm optimization

Effects of anode position on pedicle screw testing during lumbosacral spinal fusion surgery

SUMMARY OF BACKGROUND DATAPedicle screws are commonly placed with lumbar/lumbosacral fusions. Triggered electromyography (tEMG), which employs the application of electrical current between the screw and a complementary anode to determine thresholds of conduction, may be utilized to confirm the safe placement of such implants. While previous research has established clinical thresholds associated with safe screw placement, there is variability in clinical practice of anode placement which could lead to unreliable measurements. PURPOSETo determine the variance in pedicle screw stimulation thresholds when using four unique anode locations (ipsilateral/contralateral and paraspinal/gluteal relative to tested pedicle screws). STUDY DESIGNProspective cohort study. Tertiary medical center. PATIENT SAMPLETwenty patients undergoing lumbar/lumbosacral fusion with pedicle screws using tEMG OUTCOME MEASUREStEMG stimulation return values are used to assess varied anode locations and reproducibility based on anode placement. METHODSMeasurements were assessed across node placement in ipsilateral/contralateral and paraspinal/gluteal locations relative to the screw being assessed. R2 coefficients of correlation were determined, and variances were compared with F-tests. RESULTSA total of 94 lumbosacral pedicle screws from 20 patients were assessed. Repeatability was verified using two stimulations at each location for a subset of the screws with an R2 of 0.96. Comparisons between the four anode locations demonstrated R2 values ranging from 0.76 to 0.87. F-tests comparing thresholds between each anode site demonstrated all groups not to be statistically different. CONCLUSIONThe current study, a first-of-its-kind formal evaluation of anode location for pedicle screw tEMG testing, demonstrated very strong repeatability and strong correlation with different locations of anode placement. These results suggest that there is no need to change the side of the anode for testing of left versus right screws, further supporting that placing an anode electrode into gluteal muscle is sufficient and will avoid a sharp ground needle in the surgical field.

Protocol for reducing radiation exposure during pediatric thoracic radiography

IntroductionThis work aims to assess if the anode position during chest radiography of pediatric patients with heart congenital disease (HCD) influences medical image results. The approach is to reverse the orientation of the x-ray tube, with the anode end directed towards the patient's face (anode-heel effect). MethodsFive specialists analyzed 48 images, 24 from the control group (CG) and 24 with the anode end directed towards the patients' face (experimental group, EC). An ionization chamber was used to assess radiation dose received by sensitive organs. ResultsThe specialists considered both CG and EC images acceptable. But, the EC group's dose evaluation revealed that the thyroid received 12% less radiation and the gonads presented a 5.9% reduction. Based on the results, a new protocol was developed. Discussion/conclusionThe standardization of radiographic imaging procedures will reduce acquisition errors, resulting in adequate images in pediatric patients with HCD with less radiation dose, thus increasing patient safety and extending the life of the equipment.

Can you hold an advantageous network position? The role of neighborhood similarity in the sustainability of structural holes in social networks

The literature has provided multiple metrics to measure the structural position of a node in a network or its structural social capital. However, the dynamics of social capital is rarely addressed. In this article, we analyze the sustainability of the structural position of the leaders. We explore the role of neighborhood similarity and propose inbound and outbound similarity measures to address the structural hole's sustainability. To evaluate our approach, we use four real dynamic graphs and Susceptible, Infectious, or Recovered (SIR) model of epidemiology and regression analysis. We evaluate the power of our measures in predicting the evolution of the information spread of nodes, and compare the results with the measures from the literature. Our results confirm the relevance of neighborhood similarity for addressing the sustainability of social capital over time. In particular, the notions of inbound and outbound similarity proposed in this article show its relevance. The proposed framework allows better evaluation of one's strategic position in a social network and measures the potential future impact.

Method of compensating for time measurement error of photomultiplier tube

In order to improve the temporal resolution of photomultiplier tubes, our research group has conducted the in-depth research on photomultiplier tubes based on microchannel plates that are widely used at present. The time resolution of photomultiplier tube based on microchannel plate is limited by the transit time of photoelectric signal in each part, including the transit time of photoelectric signal in the transmission process of photocathode to microchannel plate, the transit time of photoelectric signal in microchannel plate time, the transit time of the photoelectric signal from the microchannel plate to the detector anode, and the transit time of the photoelectric signal on the anode to the electrode port. The transit time of the whole process has a certain degree of influence on the time information measurement of the optoelectronic signal. In this study, various parameters affecting the time resolution of the photomultiplier tube are analyzed, and it is found that the different positions of the photoelectron signal on the anode will bring errors to the measurement of the arrival time of the signal at the anode, and the photoelectric signal is transmitted to the electrode port at the affected point of the anode The spent time will cause the signal measurement time to lag behind the real time, which indirectly affects the time resolution of the system. Therefore, a specific study is carried out on the time measurement error of the signal on the anode, and it is determined that the difference of the photoelectron signal on the anode position is an important factor causing the signal time measurement error, and a simple and effective method of compensating for error is proposed. In the research process, the delay line anode is used, and the positional resolution principle of the photoelectric signal is used to obtain the position information of the photoelectron signal on the anode, and the position information is converted into the time information transmitted from the position to the electrode port. The theoretical value of the transit time on the anode is offset, eliminating unnecessary time in the time-of-arrival measurement of the photoelectron signal. The time measurement error of the optoelectronic signal is compensated for by this time information. The experimental results show that the error compensation method can effectively improve the time measurement accuracy of optoelectronic signals, and provide solutions and theoretical basis for improving the time resolution of photomultiplier tubes based on microchannel plates.

Электрохимическое осаждение контактных материалов в постростовой технологии фотоэлектрических преобразователей

Investigations and modeling of ohmic contacts electrochemical deposition process in postgrowth technology of photovoltaic converters fabrication have been carried out. The technology of Ag/Au contact system galvanic deposition at vertical and horizontal position of heterostructure and anode in the electrolyte has been developed. The increase of contact system deposition uniformity up to ∼ 95% at the thickness of contact bus-bars ∼ 5 µm on the heterostructure area with 4 inch diameter has been archived.

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Investigations and modeling of ohmic contacts electrochemical deposition process in postgrowth technology of photovoltaic converters fabrication have been carried out. The technology of Ag/Au contact system galvanic deposition at vertical and horizontal position of heterostructure and anode in the electrolyte has been developed. The increase of contact system deposition uniformity up to ∼ 95% at the thickness of contact bus-bars ∼ 5 µm on the heterostructure area with 4 inch diameter has been archived.

Heat Exchanger Network Optimization Based on the Participatory Evolution Strategy for Streams

The non-structural model of a heat exchanger network randomly selects a position of a node on hot and cold streams to generate a heat exchanger and an existing heat exchanger to participate in the evolution. Despite the model being more random and flexible, this selection method cannot easily find a good solution. In addition, the heat exchangers participating in the evolution might not be involved in all streams in each evolutionary process. A stream that does not participate in the evolution will have no significance to the current iteration. Therefore, many iterations are required to make each stream participate in the evolution, which limits the evolution efficiency of the optimization algorithm. In view of this shortcoming, this study proposes a participatory evolutionary strategy for streams based on hot streams. The proposed strategy reorders the existing heat exchangers on hot and cold streams and takes the corresponding measures to ensure that a heat exchanger is selected for each stream to participate in the evolution in every cycle. The proposed participatory evolutionary strategy for streams improves the global optimal solution for designs based on non-structural models. The effectiveness of the proposed strategy is demonstrated in two cases.