scholarly journals Device Design for Electric Arc Electromagnetic Constriction

2020 ◽  
Vol 25 ◽  
Author(s):  
Miguel Guilherme Antonello ◽  
Alexandre Queiroz Bracarense
Keyword(s):  
Weld Pool ◽  
Small Diameter ◽  
Electric Arc ◽  
Specific Power ◽  
Work Piece ◽  
Large Area ◽  
Electromagnetic Forces ◽  
Transverse Profile ◽  
Arc Shape ◽  
The Difference

Abstract: The difference of potential between two electrodes results in electric current breaking the dielectric barrier of the gas in this space causing a plasma discharge called electric arc. As a result, there is luminosity and an increase in temperature. Electric arc is used for welding and usually one of the electrodes is cylindrical with small diameter and the other with large area. Because of this configuration, the side section of the electric arc has a bell shape and forms a circular impression in contact with the work piece (the weld pool). With the use of electromagnetic forces, it is possible to change this circular impression, completely changing the behavior and consequently the geometry of the weld pool. This article presents the development and construction of a device for the electromagnetic constriction of the electric arc, capable of changing the cross section of the impression from circular to elliptical. The steps performed in the article were the simulation of the electromagnetic fields generated to change the electric arc shape, the development of the arc constriction device and the application of this electromagnetic constriction in beads on plate. The results show that the electromagnetic forces change the transverse profile of the arc from circular to elliptical, enabling the increase in specific power and a more precise orientation of the electric arc. Also, changing the orientation of the ellipse results in different penetration and width of the bead.

Correlation Between the V-I Characteristics of (0001) 4H-SiC PN Junctions Having Different Structural Features and Synchrotron X-ray Topography

2008 ◽  
Vol 1069 ◽  
Author(s):  
Ryoji Kosugi ◽  
Toyokazu Sakata ◽  
Yuuki Sakuma ◽  
Tsutomu Yatsuo ◽  
Hirofumi Matsuhata ◽  
...  
Keyword(s):  
High Energy ◽  
Structural Features ◽  
Incidence Geometry ◽  
Voltage Source ◽  
Large Area ◽  
Chip Area ◽  
Power Mosfets ◽  
X Ray ◽  
Pn Junctions ◽  
The Difference

ABSTRACTIn practical use of the SiC power MOSFETs, further reduction of the channel resistance, high stability under harsh environments, and also, high product yield of large area devices are indispensable. Pn diodes with large chip area have been already reported with high fabrication yield, however, there is few reports in terms of the power MOSFETs. To clarify the difference between the simple pn diodes and power MOSFETs, we have fabricated four pn-type junction TEGs having the different structural features. Those pn junctions are close to the similar structure of DIMOS (Double-implanted MOS) step-by-step from the simple pn diodes. We have surveyed the V-I characteristics dependence on each structural features over the 2inch wafer. Before their fabrication, we formed grid patterns with numbering over the 2inch wafer, then performed the synchrotron x-ray topography observation. This enables the direct comparison the electrical and spectrographic characteristics of each pn junctions with the fingerprints of defects.Four structural features from TypeA to TypeD are as follows. TypeA is the most simple structure as same as the standard pn diodes formed by Al+ ion implantation (I/I), except that the Al+ I/I condition conforms to that of the p-well I/I in the DIMOS. The JTE structure was used for the edge termination on all junctions. While the TypeA consists of one p-type region, TypeB and TypeC consists of a lot of p-wells. The difference of Type B and C is a difference of the oxide between the adjacent p-wells. The oxide of TypeB consists of the thick field oxide, while that of TypeC consists of the thermal oxide corresponding to the gate oxide in the DIMOS. In the TypeD structure, n+ region corresponding to the source in the DIMOS was added by the P+ I/I. The TypeD is the same structure of the DIMOS, except that the gate and source contacts are shorted. The V-I measurements of the pn junctions are performed using the KEITHLEY 237 voltage source meters with semi-auto probe machine. An active area of the fabricated pn junctions TEGs are 150um2 and 1mm2. Concentration and thickness of the drift layer are 1e16cm−3 and 10um, respectively.In order to compare the V-I characteristics of fabricated pn junctions with their defects information that obtained from x-ray topography measurements directly, the grid patterns are formed before the fabrication. The grid patterns were formed over the 2inch wafer by the SiC etching. The synchrotron x-ray topography measurements are carried out at the Beam-Line 15C in Photon-Factory in High-Energy-Accelerator-Research-Organization. Three diffraction conditions, g=11-28, -1-128, and 1-108, are chosen in grazing-incidence geometry (improved Berg-Barrett method).In the presentation, the V-I characteristics mapping on the 2inch wafer for each pn junctions, and the comparison of V-I characteristics with x-ray topography will be reported.

Electric arc shape and weld bead geometry analysis under the electromagnetic constriction and expansion effect

2021 ◽  
Author(s):  
Miguel Guilherme Antonello ◽  
Alexandre Queiroz Bracarense ◽  
Régis Henrique Gonçalves e Silva ◽  
Ivan Olszanski Pigozzo ◽  
Marcelo Pompermaier Okuyama
Keyword(s):  
Electric Arc ◽  
Weld Bead ◽  
Bead Geometry ◽  
Weld Bead Geometry ◽  
Arc Shape ◽  
Geometry Analysis ◽  
Expansion Effect

scholarly journals Tribological properties of friction composites modified by the suspended particles of exhaust flue gases

2019 ◽  
pp. 75-83
Author(s):  
T. A. Akhmetov ◽  
V. K. Merinov ◽  
N. V. Kargapolova
Keyword(s):  
Tribological Properties ◽  
Suspended Particles ◽  
Electric Arc ◽  
Flue Gases ◽  
Spherical Particles ◽  
Dynamic Friction ◽  
Dynamic Friction Coefficient ◽  
Arc Furnaces ◽  
The Matrix ◽  
The Difference

The possibility of using the deposited suspended particles of electric arc furnaces as heat-resistant modifying additives for friction composites is considered. It is shown that the precipitated particles obtained during the smelting of steel of different grades have identical morphology and are a homogeneous mechanical mixture consisting mainly of spherical particles of no more than 1 µm in size.It is established that the composites on the basis of the fluoropolymer, modified by precipitated particles obtained in the smelting of steel of various sizes have different tribological properties. This is due to the difference in the chemical composition of the deposited particles.It was found that the use of deposited particles in composite materials allows to vary the value of the dynamic friction coefficient in a wider range, in particular to obtain higher and stable values, while the wear resistance of modified friction composites is more than 500 times higher than the same index of the matrix polymer – polytetrafluoroethylene.

Different colloidal particle formation process between conjugated polymer and unmodified C60 in preparation of suspension for electrophoretic deposition by reprecipitation method

2021 ◽  
Author(s):  
Kazuya Tada ◽  
Daiya Fujimoto
Keyword(s):  
Molecular Weight ◽  
Electrophoretic Deposition ◽  
Formation Process ◽  
Colloidal Particle ◽  
Film Formation ◽  
Particle Formation ◽  
Large Area ◽  
Significant Difference ◽  
Reprecipitation Method ◽  
The Difference

Abstract Electrophoretic deposition provides material-efficient film formation on large area electrodes. In this study, it has been found that there is a significant difference in the colloidal particle formation process between a thiophene-based copolymer poly(3-octylthiophene- 2,5-diyl-co-3-decyloxythiophene-2,5-diyl) (POT-co-DOT) and C60 in preparation of suspension for electrophoretic deposition by reprecipitation method. This difference is attributed to the difference between low molecular weight materials with specific molecular weight and polymers with molecular weight distribution. The composition of POT-co-DOT:C60 composite film by electrophoretic deposition has also been estimated.

PLASMA NEW SELECTIVE PROPERTIES FOR EFFICIENT USE IN ELECTRONICS AND TELECOMMUNICATIONS

2021 ◽  
Vol 2 (64) ◽  
pp. 171-174
Author(s):  
Oleksandr Shefer ◽  
Vitalii Marchenko ◽  
Galina Cherneva
Keyword(s):  
Gaseous Medium ◽  
Charge Carriers ◽  
Practical Implementation ◽  
Large Area ◽  
Elementary Processes ◽  
Molecular Gases ◽  
Radio Signals ◽  
The Difference ◽  
Functional Purpose ◽  
Gas Pressures

In terms of active and passive electronic counteraction, detection of geophysical phenomena of artificial andnatural origin is becoming increasingly important. Discovering new properties of plasma enables to improve the informationcomponent of radio signals more effectively and use the obtained properties in related fields. Elementary processes in thelongitudinal and transverse directions of the discharge, depending on natural and artificial conditions, under different typesof gaseous medium used; at different gas pressures and different pulse-periodic application of an electric field is studied inthe article. The difference of discharge properties in inert and molecular gases with different designs and electrodes of thelaboratory device is shown. It is established that the change of functional purpose between the cathodes and the anodes doesnot change the shape of the discharge. The presence of ambipolar diffusion of charge carriers acting on a large area of plasmawas determined. Partial charge carrier homogeneity has been established, which is observed only along the plasma surface,and homogeneity is violated in the perpendicular direction. The difference in energy input in the discharge, depending on thedesign of the electrodes other things being equal is determined. The identified properties of plasma enable them to be usedmore effectively for practical implementation in the field of electronics and telecommunications and other industries.

scholarly journals Analysis and Characterization of the Weld Pool and Bead Geometry of Inconel 625 Super-TIG Welds

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 365
Author(s):  
Jung Hyun Park ◽  
Muralimohan Cheepu ◽  
Sang Myung Cho
Keyword(s):  
Production Rate ◽  
Weld Pool ◽  
Tig Welding ◽  
Fusion Welding ◽  
Inconel 625 ◽  
Bead Geometry ◽  
Weld Bead Geometry ◽  
High Production Rate ◽  
The Difference ◽  
Bead Height

The welding market is changing globally, becoming eco-friendly, robotized and automated. The tungsten inert gas welding (TIG) process is indispensable in industries that require high-quality welds with the absence of spatter and fumes. However, the production rate of TIG welding is very low, which limits its many applications. The present study introduces a novel TIG welding method called super-TIG welding. Super-TIG welding is able to produce a high production rate of welds compared to other fusion welding methods. In super-TIG welding, the novel C-type filler is used, which is different from the conventional TIG welding of circular wire. The relations of the heat input ratio in super-TIG welding to weld pool length and weld bead geometry were measured using the Inconel 625 C-filler. Two types of deposition techniques were used for a bead-on-plate welds, such as stringer beads and oscillation beads. The weld pool and bead geometry measurements are found to be different between stringer beads and oscillation bead techniques. The length of the molten pool and bead size were higher for oscillation beads over the stringer beads. These changes were associated with the difference in heat transfer contact area and bead height.

scholarly journals A Novel Button-Type Micro Direct Methanol Fuel Cell with Graphene Diffusion Layer

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 658
Author(s):  
Zhu ◽  
Gao ◽  
Li
Keyword(s):  
Fuel Cell ◽  
Power Density ◽  
Direct Methanol Fuel Cell ◽  
Direct Methanol Fuel Cells ◽  
Effective Area ◽  
Unit Weight ◽  
Specific Power ◽  
Large Area ◽  
Direct Methanol ◽  
Methanol Fuel Cell

In order to solve the problem that bolts in traditional packaged direct methanol fuel cells (DMFCs) take up a large area and reduce the specific energy (energy per unit weight) and power density (power per unit area), a new button-type micro direct methanol fuel cell (B-μDMFC) is designed, assembled, and packaged. The cell with four different structures was tested before and after packaging. The results indicate that the button cell with three-dimensional graphene and springs has the best performance. The equivalent circuit and methanol diffusion model was applied to explain the experimental results. The peak volumetric specific power density of the cell is 11.85 mW cm−3. This is much higher than traditional packaged DMFC, because the novel B-μDMFC eliminates bolts in the structure and improves the effective area ratio of the cell.

Improvement of laser beam welding by electromagnetic forces in the weld pool

2003 ◽  
Author(s):  
Guenter Ambrosy ◽  
Peter Berger ◽  
Helmut Huegel ◽  
D. Lindenau
Keyword(s):  
Laser Beam ◽  
Weld Pool ◽  
Laser Beam Welding ◽  
Electromagnetic Forces

scholarly journals Evaluation of TsHARP Utility for Thermal Sharpening of Sentinel-3 Satellite Images Using Sentinel-2 Visual Imagery

2019 ◽  
Vol 11 (19) ◽  
pp. 2304 ◽  
Author(s):  
Hanna Huryna ◽  
Yafit Cohen ◽  
Arnon Karnieli ◽  
Natalya Panov ◽  
William P. Kustas ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Land Surface ◽  
Near Infrared ◽  
Landsat 8 ◽  
Large Area ◽  
Primary Methods ◽  
Thermal Images ◽  
Spatially Distributed ◽  
The Difference ◽  
Sentinel 2

A spatially distributed land surface temperature is important for many studies. The recent launch of the Sentinel satellite programs paves the way for an abundance of opportunities for both large area and long-term investigations. However, the spatial resolution of Sentinel-3 thermal images is not suitable for monitoring small fragmented fields. Thermal sharpening is one of the primary methods used to obtain thermal images at finer spatial resolution at a daily revisit time. In the current study, the utility of the TsHARP method to sharpen the low resolution of Sentinel-3 thermal data was examined using Sentinel-2 visible-near infrared imagery. Compared to Landsat 8 fine thermal images, the sharpening resulted in mean absolute errors of ~1 °C, with errors increasing as the difference between the native and the target resolutions increases. Part of the error is attributed to the discrepancy between the thermal images acquired by the two platforms. Further research is due to test additional sites and conditions, and potentially additional sharpening methods, applied to the Sentinel platforms.

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