Temat: current density - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Current density in the unscreened three-phase high-current busduct
Autorzy:: Szczegielniak, T.
Piątek, Z.
Kusiak, D.
Tematy:: analytical method
high-current busduct
current density; Pokaż więcej
Wydawca:: Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Powiązania:: https://bibliotekanauki.pl/articles/97582.pdf Link otwiera się w nowym oknie
Opis:: Design of the high-current busducts on high currents and voltages causes necessity precise describing of electromagnetic, dynamic and thermal effects. Knowledge of the relations between electrodynamics and constructional parameters is necessary in the optimization construction process of the high-current busducts. Information about distribution electromagnetic field is a base into analysis of electrodynamics and thermal effects in the high-current busducts. The paper presents analytical calculations of the current density in the three-phase high-current busduct which phase conductors are placed in vertex of a square. Into account were taken skin and proximity effect. The electromagnetic field produced by high-current busducts are usually calculated numerically with the use of a computer. However, the analytical calculation of the electromagnetic field is preferable, because it results in a mathematical expression for showing its dependences on various parameters of the line arrangement.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: The Performance of Electrocoagulation Process in Removing Organic and Nitrogenous Compounds from Landfill Leachate in a Three-Compartment Reactor
Autorzy:: Bagastyo, Arseto Yekti
Sidik, Fahrudin
Anggrainy, Anita Dwi
Lin, Jr-Lin
Nurhayati, Ervin
Tematy:: current density
electrocoagulation
humic substance
stabilized leachate
wastewater treatment; Pokaż więcej
Wydawca:: Polskie Towarzystwo Inżynierii Ekologicznej
Powiązania:: https://bibliotekanauki.pl/articles/2027831.pdf Link otwiera się w nowym oknie
Opis:: In this study, the effectiveness of the electrocoagulation (EC) process was evaluated based on the reduction of organic and nitrogenous contaminants in landfill leachate. A three-compartment electrochemical reactor as pre-treatment of stabilized landfill leachate was carried out ahead of biological treatment. The removal efficiencies of COD, BOD, ammonia, and nitrate were analyzed at pH 4, 6, and 8 with the current densities of $20.83$ and $29.17 mA•cm^{–2}$. At pH 4, the highest removal of COD and $NH_4^+$ was obtained, i.e., in the range of 72–81% and 43–59%, respectively. The ratio of $BOD_5$/$COD$ was increased after EC, from initially 0.11 to 0.32 at pH 4. In addition, EC effectively removed humic substances in the leachate by targeting a large amount of high molecular weight humic substances, with around $10^3$ kDa. However, the higher removal efficiency observed at higher current density leads to higher specific energy consumption. At a current density of $29.17 mA•cm^{–2}$, the specific energy consumption obtained in EC was around $10–17 Wh•g^{–1}$ COD and $99–148 Wh•g^{–1}$ $NH_4^+$. This could be decreased up to 50% at an applied current density of $20.83 mA•cm^{–2}$ with slightly lower efficiencies.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Binary Classification of Heart Failures Using k-NN with Various Distance Metrics
Autorzy:: Udovychenko, Y.
Popov, A.
Chaikovsky, I.
Tematy:: magnetocardiography
current density imaging
current density distribution map
k-NN classification
negative Tpeak
heart failure diagnostics
Mahalanobis distance
Cityblock distance
Eucleadian distance
Chebyshev distance; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/226330.pdf Link otwiera się w nowym oknie
Opis:: Magnetocardiography is a sensitive technique of measuring low magnetic fields generated by heart functioning, which is used for diagnostics of large number of cardiovascular diseases. In this paper, k-nearest neighbor (k-NN) technique is used for binary classification of myocardium current density distribution maps (CDDM) from patients with negative T-peak, male and female patients with microvessels (diffuse) abnormalities and sportsmen, which are compared with normal control subjects. Number of neighbors for k-NN classifier was selected to obtain highest classification characteristics. Specificity, accuracy, precision and sensitivity of classification as functions of number of neighbors in k-NN are obtained for classification with several distance measures: Mahalanobis, Cityblock, Eucleadian and Chebyshev. Increase of the accuracy of classification for all groups up to 10% was obtained using Cityblock distance metric in binary k-NN classifier with 19 - 27 neighbors, comparing to other metrics. Obtained results are acceptable for further patient’s state evaluation.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: The Effect of Return Electrode Position on Induced Electric Fields for Electrical Stimulation of Retinal Ganglion Cells
Autorzy:: Celik, M.
Tematy:: electrical stimulation
electric field
current density
temperature
retina
visual prostheses; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1031744.pdf Link otwiera się w nowym oknie
Opis:: Age-related macular degeneration and retinitis pigmentosa are the most countered eye diseases that damage photoreceptors and cause to lose the visual sense. To regain the visual sense, studies are focused on the electrical stimulation of nerve cells remain intact. The electrical stimulation is carried out with the electrode arrays that include a certain number of stimulation electrodes and a common return electrode. In this study, the retinal stimulation is modelled using a computational model to investigate stimulation performance depending on the return electrode position and its geometrical properties. Stimulation induced electric field, current density and temperature over the retinal tissue are examined. It is seen that closer placement of return electrode and stimulation electrodes causes high electric field intensity and current density between electrodes, which is quite risky for long term chronic implementation by the reason of the increase in the temperature beyond the safe limits. It is concluded that there is an indispensability for the distances, three to five times of the electrode diameter, between electrodes to avoid electrode corrosion and tissue damage.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: The Effect of Electrochemical Machining on the Fatigue Strength of Heat Resistance Alloys
Autorzy:: Kozak, J.
Tematy:: anodic dissolution
current density
hydrogen embrittlement
intergranular attack
fatigue strength; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Powiązania:: https://bibliotekanauki.pl/articles/97757.pdf Link otwiera się w nowym oknie
Opis:: Electrochemical Machining (ECM) provides an economical and effective method for machining high strength, heat-resistant materials into complex shapes such as compressor and turbine blades, dies, molds and micro cavities. ECM is performed without physical contact between the tool and the workpiece in contrast to the mechanical machining, and without strong heating in the machining zone in distinction to the methods such as EDM. Therefore, no surface metal layer with mechanical distortion, compressive stresses, cracks, and thermal distortion forms in ECM. ECM is often used even for removing a defective layer, which has been formed in EDM, with the aim to improve the surface integrity. However, sometimes the intergranular attack occurs in ECM. This may reduce the performance of machined parts and lead to the decreasing of fatigue strength. In this paper, the effects of ECM on fatigue strength of heat resistant alloys such as nickel-base alloys and titanium alloys are presented. The problems of the intergranular attack, hydrogen embrittlement and surface roughness as result of ECM parameters are described.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: CFD modelling of hydrogen starvation conditions in a planar Solid Oxide Fuel Cell
Autorzy:: Pianko-Oprych, P.
Zinko, T.
Jaworski, Z.
Tematy:: planar Solid Oxide Fuel Cell
fuel starvation
current density
CFD modelling; Pokaż więcej
Wydawca:: Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Powiązania:: https://bibliotekanauki.pl/articles/779053.pdf Link otwiera się w nowym oknie
Opis:: The aim of this study was to highlight the interest of using CFD technique as a diagnostic tool of a malfunctioning Solid Oxide Fuel Cells. Hydrogen starvation of a SOFC due to nitrogen dilution is one of the cell dysfunctions and can lead to its degradation. Identification of the starvation point allows to improve cell performance and establish the best conditions for degradation tests. To illustrate a potential of the CFD tool, several simulations of a single planar SOFC and its behaviour under hydrogen starvation were performed and analysed. The results showed that at lower cell voltage values of 0.3 and 0.5 V significant gradients in the electric current were noticed due to a local reduction in hydrogen concentration. The CFD analysis allowed defining desirable mass flow rate of hydrogen to SOFCs to avoid fuel starvation. The model constitutes a helpful tool for optimizing cell design and operational conditions.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Effect of the Applied Current Density and Deposition Time on Electro-Codeposition Process of Cobalt Matrix Reinforced with Nano-CeO2
Autorzy:: Simionescu-Bogatu, Nicoleta
Benea, Lidia
Tematy:: electrochemical deposition
cobalt matrix
CeO2 nanoparticles
current density
electrolysis time; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/2106592.pdf Link otwiera się w nowym oknie
Opis:: This research paper aims to study the influence of some of the main parameters applied to the electrodeposition process on the nanocomposite layers obtained by strengthening the cobalt matrix with cerium oxide nanoparticles. Thus, the current efficiency (process efficiency) and the degree of inclusion of cerium oxide nanoparticles into cobalt matrix are analyzed according to the current density, the concentration of nanoparticles dispersed in the deposition electrolyte and time of the process. The choice of the optimal parameters imposed on the electrodeposition process lead to the improvement of the quality of the obtained layers, to the reduction of production costs and last but not least to the improvement of corrosion and tribocorrosion resistance of the material. The obtained results show an increase of current efficiency in the process of the deposited layers with the increase of time and current density applied. There is also a slight increasing in the current efficiency of the obtained layers with the increase of the concentration of nanoparticles dispersed in the deposition electrolyte. The increase of the current density, time and the concentration of nanoparticles also have an effect on the degree of embedded CeO2 nanoparticles into cobalt matrix for the studied nanocomposite layers. The degree of inclusion of nanoparticles decreases for the same studied system with the increasing of the current density.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: The Behaviour of Low Arsenic Copper Anodes at High Current Density in Electrorefining
Autorzy:: Zhang, Xuyong
Chen, Silei
Li, Lu
Yang, Peng
Tematy:: low arsenic anodes
high current density
anode passivation
floating slimes
cathode nodules; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Powiązania:: https://bibliotekanauki.pl/articles/59110819.pdf Link otwiera się w nowym oknie
Opis:: Arsenic is the only beneficial impurity for copper electrorefining through inhibiting anode passivation and the formation of floating slimes. The behaviour of copper anodes with different content of arsenic were studied at high current density (>280 A/m2). It showed that low arsenic anodes (As < 300 ppm) easily generated anode passivation, floating slimes and cathode nodules during the electrorefining proccess. The floating slimes, electrolyte, cathode and anode were observed and analyzed. As result, low arsenic anodes were more likely to be passivated due to their microstructure defects and irregular microstructure. Increasing electrolyte temperature and addition of glycerol were propitious to reduce low arsenic anodes’ passivation. The floating slimes occured when the concentration of As(III) in electrolyte decreased to 1 g/L, and they would be precipitated by polyacrylamide. All measures greatly improved the cathode quality at current density of 300 A/m2.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Morphology Change Of Si Deposit In Molten Salt Electrorefining
Zmiana morfologii osadu Si podczas elektrorafinacji w stopionych solach
Autorzy:: Ryu, H. Y.
Kwon, S. C.
Han, M. H.
An, Y. S.
Lee, J. S.
Lee, J. H.
Tematy:: molten salt
silicon
morphology
electrorefining
current density
sól stopiona
krzem
morfologia
elektrorafinacja
gęstość prądu; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/354346.pdf Link otwiera się w nowym oknie
Opis:: The effects of processing parameters on the morphology change in a Si deposit recovered by means of molten salt electrorefining are evaluated using electrochemical techniques such as cyclic voltammetry and chronopotentiometry at 800°C. It was found that concentration of K₂SiF₆ and current density were important parameters in determining deposit size. Higher concentrations of K₂SiF₆ were effective in coarsening the silicon deposit and decreasing the cell potential. Silicon nanofiber was recovered at 5 wt% of K₂SiF₆ whereas dense particles were prepared at 30 and 50 wt% of K₂SiF₆. The morphology of the Si deposit was determined by the concentration of Si in the electrolyte which is related to the formation of crystal and growth of Si. The formation mechanism of the Si deposit was interpreted by using high resolution TEM as well as electrochemical properties.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Effect of Cathodic Current Density on Microstructure and Properties of Nickel Composite Coatings
Wpływ katodowej gęstości prądu na mikrostrukturę i właściwości niklowych powłok kompozytowych
Autorzy:: Nowak, M.
Opyrchał, M.
Boczkal, S.
Żelechowski, J.
Najder, A.
Karaś, M
Tematy:: electrodeposition
current density
composite coatings
Al2O3
elektroosadzanie
gęstość prądu
powłoki kompozytowe; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/353679.pdf Link otwiera się w nowym oknie
Opis:: Studies were carried out to characterise the nickel composite coatings deposited on a 2xxx series aluminium alloy. The composite coatings were prepared in a Watts bath with the addition of fine-dispersed particles of Al2O3 powder introduced in an amount of 100 g/l using current densities of 2, 4, 6 and 8 A/dm2. The morphology, structure, thickness and microhardness of the obtained composite coatings were described. The volume fraction of Al2O3 particles in composite coating was determined. The corrosion resistance of thus produced coatings was examined. Based on the results of the conducted studies it was stated that all the produced coatings were characterised by good adhesion to the substrate, but coatings produced at high current densities were characterised by a lower content of the Al2O3 reinforcing phase present in the composite.
W pracy przedstawiono badania charakteryzujące kompozytowe powłoki niklowe osadzane na stopie aluminium serii 2xxx. Powłoki kompozytowe wytwarzano w kąpieli Wattsa z dodatkiem drobnodyspersyjnych cząstek proszku AI2O3 w ilości 100 g/l przy zastosowaniu gęstości prądu: 2, 4. 6 oraz 8 A/dm2. Przedstawiono morfologię, strukturę, grubość oraz mikrotwardość uzyskanych powłok kompozytowych. Określono objętościowy udział cząstek AI2O3 w powłoce kompozytowej. Zbadano odporność korozyjną wytworzonych powłok. Na podstawie przeprowadzonych badań stwierdzono, iż wszystkie uzyskane powłoki są dobrze przyczepne do podłoża, jednak powłoki uzyskane przy wyższych gęstościach prądów charakteryzują się niższą zawartością fazy zbrojącej AI2O3 w kompozycie.
Dostawca treści:: Biblioteka Nauki

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