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Contact area

About: Contact area is a research topic. Over the lifetime, 12358 publications have been published within this topic receiving 256401 citations. The topic is also known as: contact patch & contact region.


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Journal ArticleDOI
TL;DR: In this article, the rear contact formation of the passivated emitter and rear cell device structure is analyzed, and it is shown that the contact resistivity of fine screen printed Al fingers alloyed on narrow p-type Si areas depends on the geometry of the Al-Si alloy formation below the contacts.
Abstract: For high efficiency silicon solar cells, the rear surface passivation by a dielectric layer has significant advantages compared to the standard fully covered Al back-contact structure. In this work the rear contact formation of the passivated emitter and rear cell device structure is analyzed. Contrary to expected views, we found that the contact resistivity of fine screen printed Al fingers alloyed on narrow p-type Si areas depends on the geometry of the Al–Si alloy formation below the contacts, and decreases by reducing the contact area, while the contact resistance remains constant. At the solar cell level, the reduction in the contact resistivity leads to a minimization of the fill factor losses. At the same time, narrow Al–Si alloy formations increased the passivated area below the contacts, improving the optical properties of the rear side, reducing the short-circuit current and open-circuit voltage losses. Scanning electron microscopy analysis of the Al–Si alloy geometry is performed, in order to u...

61 citations

Journal ArticleDOI
TL;DR: In this article, a series of nanoindentation experiments on quartz, an abundant mineral in the earth's crust, was conducted, which demonstrated the utility of using continuous stiffness measurements as a means of obtaining reliable indentation creep data on hard materials like quartz.
Abstract: The frictional behavior of rocks in the laboratory is reasonably well described by rate- and state-variable friction laws, which reproduce a rich variety of natural phenomena when used in models of earthquakes. Despite the widespread adoption of the rate and state formalism in earthquake mechanics, the physical mechanisms that occur at microscopic contacting asperities on the sliding surface, which give rise to the observed rate and state effects, are still poorly understood. In an attempt to identify these underlying mechanisms, a series of nanoindentation experiments on quartz, an abundant mineral in the earth’s crust, was conducted. These experiments demonstrate the utility of using continuous stiffness measurements as a means of obtaining reliable indentation creep data on hard materials like quartz at room temperature. The projected area of indentation in quartz increases linearly with the logarithm of the time of indentation, in agreement with the increase in real area of contact with log time inferred from slide-hold-slide friction experiments on quartz rocks. However, the increase in fractional area with time in the indentation tests was larger than that inferred from friction experiments by a factor of 1.7. Differences between the rates of fractional area increase in the two tests may indicate that the increase in contact area during the hold portion of slide-hold-slide tests was modulated by slip that occurs during reloading after the hold, as was observed for other materials. The nanoindentation results suggest that the increase in frictional strength (i.e., the increase of state in the rate- and state-variable friction laws) during slide-hold-slide friction experiments was caused by creep of the highly stressed asperity contacts.

61 citations

Journal ArticleDOI
TL;DR: Compared in vivo contact mechanics for 10 subjectsHaving a fixed-bearing high-flexion posterior-stabilized (LPS-Flex) TKA and 10 subjects having a Fixed- bearing high- flexion posterior cruciate-retaining (CR-F Flex) TKO, both these implants were able to maintain sufficient contact area so the contact stress values were well below the yield strength of crosslinked polyethylene.
Abstract: To accommodate for high flexion, new total knee arthroplasties (TKAs) have been designed. Unlike older designs which have been found to exhibit decreasing contact area with increasing flexion, we hypothesized the new designs would be associated with improved contact mechanics. We compared in vivo contact mechanics for 10 subjects having a fixed-bearing high-flexion posterior-stabilized (LPS-Flex) TKA and 10 subjects having a fixed-bearing high-flexion posterior cruciate-retaining (CR-Flex) TKA. All subjects performed deep knee bends to maximum flexion while under fluoroscopic surveillance. In vivo kinematics obtained using a three-dimensional to two-dimensional registration technique, were input into a three-dimensional inverse dynamic mathematical model to determine the contact forces. The contact areas and contact stresses were determined using a deformable contact model. The contact forces, contact areas, and contact stresses in both these implants increased with increasing flexion. The medial contact area in the LPS-Flex was higher than the CR-Flex for most of the flexion cycle. The lateral contact area was higher in the CR-Flex than the LPS-Flex in early and midflexion ranges. Although the lateral contact stresses were similar in both implants, the CR-Flex experienced higher medial contact stress than the LPS-Flex throughout flexion. However, both these implants were able to maintain sufficient contact area so the contact stress values were well below the yield strength of crosslinked polyethylene.

60 citations

Journal ArticleDOI
01 Jan 1976-Wear
TL;DR: In this paper, an asperity-based model was obtained by applying the most general Hertzian equations for elastic deformation to the random surface model of Longuet-Higgins.

60 citations

Journal ArticleDOI
TL;DR: In this paper, the tribological behavior of nano-MoS2 sheet mixed with different percentages of Polyisobutyleneamine Succinimide (PIBS) was explored.

60 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023102
2022253
2021375
2020467
2019554
2018528