Hydro-transportation is an economic and flexible way to transport natural resources such as oil and gas from excavation to the extraction plants, refineries, and consumer-ready products to markets. However, interactio...
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Organic-inorganic melting gel coatings were applied to titanium alloy substrates to decrease their corrosion and extend their lifetime in an electrochemical application. Melting gels containing phenyl substitutions we...
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ISBN:
(纸本)9781119323617
Organic-inorganic melting gel coatings were applied to titanium alloy substrates to decrease their corrosion and extend their lifetime in an electrochemical application. Melting gels containing phenyl substitutions were coated onto the substrates. The ratio of diphenyl dimethoxysilane (DphdMS) to methanol was varied to change the thickness of the coatings. The coatings were inspected visually to see that there is good adhesion between the coating and the substrate. Nanoindenter tests were performed to determine hardness.
TiCxN1-x (with x = 0.7, 0.5 and 0.3) cermets were successfully prepared with 40 vol.% Ni3Al metallic binder, using a simple melt-infiltration sintering process. In order to assess their susceptibility to electrochemic...
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Retinitis Pigmentosa (RP) is a degenerative disease of the retina that leads to vision loss. Retinal prostheses are being developed in order to restore functional vision in patients suffering from RP. We conducted in-...
Retinitis Pigmentosa (RP) is a degenerative disease of the retina that leads to vision loss. Retinal prostheses are being developed in order to restore functional vision in patients suffering from RP. We conducted in-vivo experiments in order to identify strategies to efficiently stimulate the retina. We electrically stimulated the retina and measured electrically evoked potentials (EERs) from the superior colliculus of rats. We compared the strength of EERs when voltage-controlled and current-controlled pulses of varying pulse width and charge levels were applied to the retina. In addition to comparing EER strength, we evaluated improvement in power efficiency afforded by a high surface area platinum-iridium material. Voltage-controlled pulses were more efficient than current-controlled pulses when the pulses have a short duration (
Due to light weight, high specific strength, high corrosion resistance and good heat transfer ability, aluminium alloys are becoming attractive for critical structural applications. These alloys can be manufactured us...
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Due to light weight, high specific strength, high corrosion resistance and good heat transfer ability, aluminium alloys are becoming attractive for critical structural applications. These alloys can be manufactured using powder metallurgy techniques in which porosity is a common characteristic. The presence of pores is responsible for decreasing effective load bearing cross sectional area and inducing stress concentration sites for strain localization and damage, decreasing both strength and ductility. The present study aims to establish a better understanding of the relationship between surface porosity and corresponding wear behavior. In this study, porous specimens were produced using powder metallurgy technique and the extent of wear damage and the type of wear was investigated under low load range of 1.5 - 5 N against AISI 52100 bearing steel ball using a reciprocating ball-on-flat configuration and frequency of 10 Hz. Scanning electron microscopy of the wear tracks and wear debris was carried out to understand wear mechanisms. This study revealed that due to combined effect of high stress intensity and subsurface cracking, wear rate increases with increasing porosity content. The friction and wear behavior of pure Al and Al 6061 as a function of porosity content can be attributed to their hardness and corresponding wear mechanism.
Due to their light weight, high corrosion resistance and good heat conductivity, aluminium alloys are used in many industries today. They are suitable for manufacturing many automotive components such as clutch housin...
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Due to their light weight, high corrosion resistance and good heat conductivity, aluminium alloys are used in many industries today. They are suitable for manufacturing many automotive components such as clutch housings. These alloys can be fabricated by powder metallurgy and casting methods, in which porosity is a common feature. The presence of pores is responsible for reducing their strength, ductility and wear resistance. The present study aims to establish an understanding of the tribological behavior of high pressure die cast Al A380M and powder metallurgy synthesized Al 6061. In this study, dry sliding wear behavior of Al A380M and Al 6061 alloys was investigated under low loads (1.5 N – 5 N) against AISI 52100 bearing steel ball using a reciprocating ball-on-flat configuration and frequency of 10 Hz. Wear mechanisms were studied through microscopic examination of the wear tracks. This study revealed that due to combined effect of real area of contact and subsurface cracking, wear rate increased with increasing porosity content. The difference in friction and wear behavior between received Al A380M and Al 6061 is attributed to their hardness differences.
Indentation and reciprocating wear tests are carried out to study dent and wear resistance of superelastic Ti-Ni alloys. The effect of loading rate on the superelastic behavior of TiNi under indentation loading is inv...
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Indentation and reciprocating wear tests are carried out to study dent and wear resistance of superelastic Ti-Ni alloys. The effect of loading rate on the superelastic behavior of TiNi under indentation loading is investigated and compared to a new generation of shape memory alloys, i.e., 60NiTi. Only limited amount of work has been done to investigate the dependency of superelasticity on loading rate of TiNi under localized compressive loads, but much work is directed towards understanding the effect of strain rate on tensile properties. Understanding the superelastic behavior helps to employ superelastic alloys in applications where high impact loading is expected as in bearings and gears. In the present study, it is found that dent resistance of Ti-Ni alloy is not significantly affected by loading rate (within the employed loading conditions). It has also been found that new-generation 60NiTi alloy exhibits superior wear and dent resistance, as well as higher hardness compared to equiatomic TiNi.
Scholarly studies and national reports document failure of current efforts to achieve broad, sustained adoption of research-based instructional practices, despite compelling bodies of evidence supporting efficacy of m...
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Scholarly studies and national reports document failure of current efforts to achieve broad, sustained adoption of research-based instructional practices, despite compelling bodies of evidence supporting efficacy of many of these practices. The authors of this paper argue that many change agents who are working to promote systemic adoption of these teaching practices use approaches that are characterized by what the authors call the "dissemination paradigm." A dissemination paradigm characterizes patterns of these current, failing efforts. Change agents, working within the dissemination paradigm, try to convince adopters that their innovations can help their students. Efforts within the dissemination paradigm have not led, and are unlikely to lead, to systemic adoption. The authors offer the "propagation paradigm" as an alternative with the potential to produce improved results. Change agents, working within the propagation paradigm, engage with adopters early and often to understand their instructional systems and interactively develop a strong product adaptable to specific contexts.
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