electric resistance
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Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 650
Author(s):  
Lenka Kunčická ◽  
Radim Kocich ◽  
Petr Kačor ◽  
Michal Jambor ◽  
Miroslav Jopek

The nature of alternating current transfer via metallic materials is specific, since the current density tends to be inhomogeneous across the cross-section of the conductor and the skin effect tends to occur. However, the influence of this effect on the behaviour of the conductor can be optimized via the design and fabrication procedures. The study presents innovative design of an Al–Cu clad conductor, which is supposed to affect favourably the influence of the skin effect. The clad conductors of various diameters (20 mm, 15 mm, and 10 mm) were fabricated via rotary swaging at room temperature, and their electric characteristics were subsequently examined both experimentally and via numerical simulations. Structure analyses performed to document the effects of the swaging technology on the development of substructure and characteristic structural features were carried out by scanning electron microscopy (electron backscatter diffraction analyses), and transmission electron microscopy. The results showed that the design of the composite has a favourable effect on decreasing the power losses during alternating current transfer and that the substructure development affected favourably the electric resistance of the conductor. The highest electric resistance was measured for the composite conductor with the diameter of 20 mm (1.8% increase compared to electric resistance during transfer of direct current). This value then decreased to 0.6%, and 0.1% after swaging down to the diameters of 15 mm, and 10 mm; the 10 mm composite featured the finest grains, partially restored structure, and texture randomization compared to the 20 mm and 15 mm composites. Manufacturing of the clad composite via rotary swaging imparted advantageous combinations of both the electric and mechanical properties, as swaging also introduced increased microhardness.


2022 ◽  
Vol 1049 ◽  
pp. 124-129
Author(s):  
Sergey Yu. Kireev ◽  
Svetlana N. Kireeva ◽  
Anatoly Frolov ◽  
Alfiya Yangurazova ◽  
Konstantin Anopin

Technological parameters for electroplating cadmium alloy (Cd (24)-In and Cd (33)-Sn) coatings from low toxic solutions have been proposed. Since the fabricated alloy coatings possess low internal stress and microhardness, good adhesion property, high corrosion and wear resistance, they can be used as protective coatings for machine building products to enhance reliability and operability thereof. The presence of good solderability and low values of transient electric resistance in climatic testing favor these coatings to be applied in hetero-structured contact systems of instrument making products for increasing their reliability and operability in a tropical marine climate.


2022 ◽  
Vol 9 (1) ◽  
pp. 25
Author(s):  
Rosanna Marsella ◽  
Rachel Wilkes ◽  
Kim Ahrens

Canine progenitor epidermal keratinocytes (CPEK) are used as canine keratinocyte cell line. Their suitability for skin barrier studies is unknown. Measurement of transepithelial electric resistance (TEER) evaluates epithelial permeability. We compared TEER and tight junction (TJ) expression in CPEKs and normal keratinocytes (NK) harvested from biopsies of normal dogs. CPEKs and NK were grown until confluence (D0) and for 13 additional days. Slides were fixed on D0 and stained with ZO-1 and claudin-1 antibodies. Five images/antibody were taken, randomized and evaluated blindly by three investigators for intensity, staining location, granularity, and continuousness. Cell size and variability were evaluated. TEER increased overtime to 2000 Ohms/cm in NK, while remained around 100–150 Ohms/cm in CPEK. ANOVA showed significant effect of time (p < 0.0001), group (p < 0.0001) and group x time interaction (p < 0.0001) for TEER. Size of CPEKs was significantly (p < 0.0001) smaller and less variable (p = 0.0078) than NK. Intensity of claudin-1 staining was greater in CPEKs (p < 0.0001) while granularity was less in CPEKs (p = 0.0012). For ZO-1, cytoplasmic staining was greater in CPEK (p < 0.0001) while membrane continuousness of staining was greater in NK (p = 0.0002). We conclude that CPEKs grown in monolayer are not representative of NK for permeability studies.


2021 ◽  
Author(s):  
Dong-il Song

Abstract In this research, we investigate the thermoelectric effects of general materials. The results of this showed that an electromotive force was generated under a temperature difference between two points in materials. As no material has infinite electric resistance, an electromotive force is expected to be generated under a temperature difference in all materials. In conclusion, the thermoelectric effect generates an electromotive force. This electromotive force causes an electric current to flow, thereby generating a magnetic field.This magnetic field generates the Earth's magnetic field, triboelectricity, sunspots, and kinetic energy of celestial bodies.This temperature differential electromotive force also generates lightning and creates an ionosphere that reflects radio waves.


2021 ◽  
Author(s):  
Dong-il Song

Abstract In this research, we investigate the thermoelectric effects of general materials. The results of this showed that an electromotive force was generated under a temperature difference between two points in materials. As no material has infinite electric resistance, an electromotive force is expected to be generated under a temperature difference in all materials. In conclusion, the thermoelectric effect generates an electromotive force. This electromotive force causes an electric current to flow, thereby generating a magnetic field. This magnetic field generates the Earth's magnetic field, triboelectricity, sunspots, and kinetic energy of celestial bodies. This temperature differential electromotive force also generates lightning and creates an ionosphere that reflects radio waves.


Author(s):  
A Reichel ◽  
RFV Sampaio ◽  
JPM Pragana ◽  
IMF Bragança ◽  
CMA Silva ◽  
...  

This paper is focused on hybrid busbars made from copper and aluminum strips and presents a flexible tool demonstrator capable of replicating material flow in the lancing, bending and compression stages of a new joining by forming process without auxiliary elements. The flexible tool demonstrator is defined by its modular concept that allows the active tool components to be easily interchanged for testing and exploring different materials and thickness combinations, surface conditions and cross-section areas of the strips under laboratory conditions. Experimental and numerical simulation with a selected hybrid busbar geometry validates the overall concept and fabrication of the demonstrator and shows that the new joining by forming process can produce permanent form-fit joints with smooth upper and lower surfaces containing all the plastically deformed material within the thickness of the two strips. Complete filling of the free volume left in-between the thickness of the two strips allows obtaining an electric resistance lower than that of fastened hybrid busbars.


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