Effects of Certain Variables on the Materials Properties of Nickel Electrodeposits: Current Density and Duty Cycle

2007 ◽  
Vol 119 ◽  
pp. 87-90 ◽  
Author(s):  
Dong Jin Kim ◽  
Hong Pyo Kim ◽  
Joung Soo Kim ◽  
Kee Won Urm ◽  
Sun Ho Lee
Keyword(s):  
Current Density ◽  
Duty Cycle ◽  
Material Properties ◽  
Hydrogen Reduction ◽  
Strain Curve ◽  
Reduction Reaction ◽  
Applied Current ◽  
Stress Strain ◽  
Nickel Ion ◽  
Applied Current Density

Alloy 600 tubing can be repaired by using a Ni electroplating to have an excellent SCC resistance. In order to carry out a successful Ni electrodeposition inside a steam generator tubing, the effects of various parameters on the material properties of the electrodeposit should be elucidated. Hence this work deals with the effects of the applied current density and the duty cycle(Ton / (Ton + Toff)) of the pulse current on the material properties of the Ni electrodeposit obtained from a Ni sulphamate bath by analyzing the current efficiency, the potentiodynamic curve, the hardness and the stress-strain curve. Hardness, YS(yield strength) and TS(tensile strength) decreased whereas the elongation increased as the applied current density increased. This was due to a concentration depletion of the nickel ion at the interface of the electrodeposit/solution, and a fractional decrease of the hydrogen reduction reaction. As the duty cycle increased, the hardness, YS and TS decreased while the elongation increased. During an off time at a high duty cycle, the concentration depletion of the nickel ion could not be sufficiently recovered and the fraction of the hydrogen evolution reaction which is kinetically faster than the nickel ion reduction decreased, which contributed to a coarse grain sized electrodeposit. The experimental results of the hardness and the stress-strain curves were supplemented by the results of the potentiodynamic curve.

scholarly journals Infarcted Left Ventricles Have Stiffer Material Properties and Lower Stiffness Variation: Three-Dimensional Echo-Based Modeling to Quantify In Vivo Ventricle Material Properties

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Longling Fan ◽  
Jing Yao ◽  
Chun Yang ◽  
Dalin Tang ◽  
Di Xu
Keyword(s):  
Wall Thickness ◽  
Material Properties ◽  
Strain Curve ◽  
Stress And Strain ◽  
Stress Strain ◽  
Material Stiffness ◽  
The Mean ◽  
Lv Volume ◽  
Parameter Values

Methods to quantify ventricle material properties noninvasively using in vivo data are of great important in clinical applications. An ultrasound echo-based computational modeling approach was proposed to quantify left ventricle (LV) material properties, curvature, and stress/strain conditions and find differences between normal LV and LV with infarct. Echo image data were acquired from five patients with myocardial infarction (I-Group) and five healthy volunteers as control (H-Group). Finite element models were constructed to obtain ventricle stress and strain conditions. Material stiffening and softening were used to model ventricle active contraction and relaxation. Systolic and diastolic material parameter values were obtained by adjusting the models to match echo volume data. Young's modulus (YM) value was obtained for each material stress–strain curve for easy comparison. LV wall thickness, circumferential and longitudinal curvatures (C- and L-curvature), material parameter values, and stress/strain values were recorded for analysis. Using the mean value of H-Group as the base value, at end-diastole, I-Group mean YM value for the fiber direction stress–strain curve was 54% stiffer than that of H-Group (136.24 kPa versus 88.68 kPa). At end-systole, the mean YM values from the two groups were similar (175.84 kPa versus 200.2 kPa). More interestingly, H-Group end-systole mean YM was 126% higher that its end-diastole value, while I-Group end-systole mean YM was only 29% higher that its end-diastole value. This indicated that H-Group had much greater systole–diastole material stiffness variations. At beginning-of-ejection (BE), LV ejection fraction (LVEF) showed positive correlation with C-curvature, stress, and strain, and negative correlation with LV volume, respectively. At beginning-of-filling (BF), LVEF showed positive correlation with C-curvature and strain, but negative correlation with stress and LV volume, respectively. Using averaged values of two groups at BE, I-Group stress, strain, and wall thickness were 32%, 29%, and 18% lower (thinner), respectively, compared to those of H-Group. L-curvature from I-Group was 61% higher than that from H-Group. Difference in C-curvature between the two groups was not statistically significant. Our results indicated that our modeling approach has the potential to determine in vivo ventricle material properties, which in turn could lead to methods to infer presence of infarct from LV contractibility and material stiffness variations. Quantitative differences in LV volume, curvatures, stress, strain, and wall thickness between the two groups were provided.

scholarly journals Methiocarb Degradation by Electro-Fenton: Ecotoxicological Evaluation

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5893
Author(s):  
Faléstine Souiad ◽  
Ana Sofia Rodrigues ◽  
Ana Lopes ◽  
Lurdes Ciríaco ◽  
Maria José Pacheco ◽  
...  
Keyword(s):  
Current Density ◽  
Iron Concentration ◽  
Model Organism ◽  
Anodic Current Density ◽  
Applied Current ◽  
Boron Doped Diamond ◽  
Applied Current Density ◽  
Toxic Units ◽  
Boron Doped ◽  
Ecotoxicological Evaluation

This paper studies the degradation of methiocarb, a highly hazardous pesticide found in waters and wastewaters, through an electro-Fenton process, using a boron-doped diamond anode and a carbon felt cathode; and evaluates its potential to reduce toxicity towards the model organism Daphnia magna. The influence of applied current density and type and concentration of added iron source, Fe2(SO4)3·5H2O or FeCl3·6H2O, is assessed in the degradation experiments of methiocarb aqueous solutions. The experimental results show that electro-Fenton can be successfully used to degrade methiocarb and to reduce its high toxicity towards D. magna. Total methiocarb removal is achieved at the applied electric charge of 90 C, and a 450× reduction in the acute toxicity towards D. magna, on average, from approximately 900 toxic units to 2 toxic units, is observed at the end of the experiments. No significant differences are found between the two iron sources studied. At the lowest applied anodic current density, 12.5 A m−2, an increase in iron concentration led to lower methiocarb removal rates, but the opposite is found at the highest applied current densities. The highest organic carbon removal is obtained at the lowest applied current density and added iron concentration.

Electrodeposition of Polyhedral Copper Crystals on Porous Silicon

2011 ◽  
Vol 181-182 ◽  
pp. 434-438
Author(s):  
Ming Meng ◽  
Yuan Ming Huang
Keyword(s):  
Porous Silicon ◽  
Current Density ◽  
Copper Chloride ◽  
Applied Current ◽  
Sem Images ◽  
Copper Crystal ◽  
Applied Current Density ◽  
Current Density Range ◽  
Tentative Explanation ◽  
Copper Crystals

Electrochemical deposition of copper from copper chloride aqueous electrolyte on porous silicon (PS) substrate was investigated in the current density range of 5 mA/cm2to 35 mA/cm2. Scanning electron microscopy (SEM) was utilized to characterize the surface morphology of as-electrodeposited PS. SEM images illustrate that the applied current density has a profound influence on the shape of copper crystal electrodeposited on the top surface of PS films. When the applied current density was fixed at 5mA/cm2, most of the copper crystals are in the shape of cube along with a small number of cuboid-shape. With the increasing current density, cuboid-shaped copper crystals gradually vanished. When the current density is up to the 35mA/cm2, we surprisingly observe that the cube shape predominates simultaneously with the emergence of truncated tetrahedron. A tentative explanation for the growth mechanism of copper crystal having various shapes is explored.

Investigation on the conductivity-dependent performance in low voltage cathodoluminescence

2015 ◽  
Vol 17 (15) ◽  
pp. 9936-9941 ◽  
Author(s):  
Chunyu Shang ◽  
Jinxian Zhao ◽  
Xiuqin Wang ◽  
Hongyang Xia ◽  
Hui Kang
Keyword(s):  
Current Density ◽  
Low Voltage ◽  
Generation Rate ◽  
Applied Current ◽  
Electron Hole ◽  
Phosphor Layer ◽  
Applied Current Density ◽  
Hole Generation

With the increase of applied current density in low voltage cathodoluminescence, the exciting power tends to saturate, causing the saturation of electron–hole generation rate in the phosphor layer.

Study of Forward Voltage Drift in Diffused SiC PiN Diodes Doped by Al or B

2005 ◽  
Vol 483-485 ◽  
pp. 989-992 ◽  
Author(s):  
S.I. Maximenko ◽  
Stanislav I. Soloviev ◽  
A.E. Grekov ◽  
A.V. Bolotnikov ◽  
Ying Gao ◽  
...  
Keyword(s):  
Current Density ◽  
Room Temperature ◽  
Stacking Faults ◽  
Applied Current ◽  
Forward Voltage ◽  
Pin Diodes ◽  
Applied Current Density ◽  
Voltage Drift ◽  
Significant Change ◽  
Degradation Testing

The degradation of diffused SiC PIN diodes during forward-biased operation was studied by first fabricating PIN diodes by diffusion of aluminum or boron into 4H-SiC substrates with n-type 10-15 µm thick epilayers doped by nitrogen up to 5x1015cm-3. The formed diodes were subjected to degradation testing under an applied current density of 200A/cm2 at room temperature. The majority of the Al diffused diodes demonstrated a voltage drift, ΔVf, of more than 2 V, while B-doped diodes showed no significant change in forward voltage. The EBIC mode of SEM was employed to monitor nucleation and expansion of stacking faults.

scholarly journals Study of the Use of Sawdust and Mycelium Composite as a Substitute of EPS

2021 ◽  
pp. 67-72
Author(s):  
R. Miralbes ◽  
D. Ranz ◽  
D. Zouzias
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Material Properties ◽  
Strain Curve ◽  
Expanded Polystyrene ◽  
Low Density ◽  
Stress Strain ◽  
Petroleum Origin ◽  
Small Grains ◽  
Substitute Material

AbstractExpanded polystyrene foams are a petroleum-origin material that is usually used in some applications such as motorcyclist helmets. Despite it notably mechanical properties, it low density and its capability to absorb energy during an impact, it is necessary to find a renewable-origin substitute material. Thus, it has been studied the use of a sawdust and mycelium composite material under quasi-static and dynamic efforts. Sawdust is a waste material that has very small grains that are totally disaggregated so it has very low material properties. The use of oyster mushroom mycelium generates an internal structure that joins grains and, consequently, the resultant material has notably high mechanical properties. Then it has been compared the resultant properties (stress-strain curve, absorbed energy, decelerations, etc.) with the different densities EPS ones and it has been concluded that this composite material, despite it high density, it could be a suitable substitute material and in some cases it has better properties.

scholarly journals Dynamics of chiral solitons driven by polarized currents in monoaxial helimagnets

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Victor Laliena ◽  
Sebastian Bustingorry ◽  
Javier Campo
Keyword(s):  
Current Density ◽  
Steady Motion ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
Applied Current ◽  
Applied Current Density ◽  
Magnetic Structures ◽  
And Control ◽  
Moriya Interaction ◽  
Chiral Solitons

AbstractChiral solitons are one dimensional localized magnetic structures that are metastable in some ferromagnetic systems with Dzyaloshinskii–Moriya interactions and/or uniaxial magnetic anisotropy. Though topological textures in general provide a very interesting playground for new spintronics phenomena, how to properly create and control single chiral solitons is still unclear. We show here that chiral solitons in monoaxial helimagnets, characterized by a uniaxial Dzyaloshinskii–Moriya interaction, can be stabilized with external magnetic fields. Once created, the soliton moves steadily in response to a polarized electric current, provided the induced spin-transfer torque has a dissipative (nonadiabatic) component. The structure of the soliton depends on the applied current density in such a way that steady motion exists only if the applied current density is lower than a critical value, beyond which the soliton is no longer stable.

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