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Full-Text Articles in Engineering

Tribological Performance Of Novel Nickel-Based Composite Coatings With Lubricant Particles, Ignacio Tudela, Andrew J. Cobley, Yi Zhang Oct 2020

Tribological Performance Of Novel Nickel-Based Composite Coatings With Lubricant Particles, Ignacio Tudela, Andrew J. Cobley, Yi Zhang

Friction

The present study is focused on the evaluation of the tribological performance of novel Ni/hBN and Ni/WS2 composite coatings electrodeposited from an additive-free Watts bath with the assistance of ultrasound. Lubricated and non-lubricated scratch tests were performed on both novel composite coatings and on standard Ni deposits used as a benchmark coating to have an initial idea of the effect of the presence of particles within the Ni matrix. Under lubricated conditions, the performance of the Ni/hBN composite coating was very similar to the benchmark Ni coating, whereas the Ni/WS2 behaved quite differently, as the latter did not only show …


Development Of Novel Catalysts For Hydrogen Gas Production From Biomass Compounds, Boanerges Bamaca Aug 2020

Development Of Novel Catalysts For Hydrogen Gas Production From Biomass Compounds, Boanerges Bamaca

Department of Biological Systems Engineering: Dissertations and Theses

Hydrothermal biomass gasification technologies (sub- and supercritical water gasification and aqueous-phase reforming) have considerable economic, environmental, and technical advantages over other energy-extensive technologies (e.g. natural gas reforming) for hydrogen gas production. However, lack of economically feasible and highly active catalysts is a main challenge that impedes upscaling of these technologies for hydrogen gas production.

The goal of this study was to develop innovative, economically feasible and active heterogeneous supported metal catalysts for hydrothermal processes for producing hydrogen gas from biomass-derived compounds. Because of its stable structure and chemical inertness, graphene was used as catalyst support. Graphene supported metal catalysts were …


Structure And Deformation Of Carbyne Deposited On A Nickel Substrate, Abigail Eaton May 2020

Structure And Deformation Of Carbyne Deposited On A Nickel Substrate, Abigail Eaton

Mechanical Engineering Undergraduate Honors Theses

Carbyne is a nanomaterial of great interest due to its ability to withstand high forces similarly to other carbon allotropes such as graphene or carbon nanotubes. However, it is currently difficult to synthesize and maintain without the assistance of a composite material substrate that the carbyne can be integrated with, which will affect its reaction to varying conditions. This thesis focuses on studying the effects of carbyne on a nickel surface and its mechanical properties to predict its future usages and potential for applications in varying fields. We perform a three-point bending test simulation using molecular dynamics with pure Ni …


Geophysical Characteristics Of Nickel And Copper Deposits In Wadi Al Khadra Prospect, Southwestern Of Saudi Arabia, Abdulrahman Ahmed Aljabbab Jan 2020

Geophysical Characteristics Of Nickel And Copper Deposits In Wadi Al Khadra Prospect, Southwestern Of Saudi Arabia, Abdulrahman Ahmed Aljabbab

Doctoral Dissertations

“Three geophysical datasets (self-potential, magnetics, and time - domain electromagnetics) were acquired at Wadi Al Khadra Ni-Cu prospect in southwest Saudi Arabia, and were processed and interpreted for the Saudi Geological Survey. The primary objectives were to map the distribution of metallic mineralization, map structures, verify the integration of the geophysical interpretations and its signatures in conjunction with boreholes information, distinguish the similarities and differences in the integrated interpretation of geophysical data, and design optimal processing and interpretation data parameters. The self-potential tool was used to map the variation in natural surface potential differences to map lateral variations in the …


Fabrication And Characterization Of Nickel Plated Micro-Resonators For Noncommutative Orientation Control In Microrobots, Marc Manheim Jan 2020

Fabrication And Characterization Of Nickel Plated Micro-Resonators For Noncommutative Orientation Control In Microrobots, Marc Manheim

Theses and Dissertations--Mechanical Engineering

This thesis describes a procedure for fabricating arrays of microstructures out of SU-8 photoresist and nickel, which was developed with the goal of yielding microrobots capable of 1D rotation byway of magnetically-induced beam vibration that could be used for non-commutative orientation control. Several multi-layer geometries were designed, fabricated, tested and refined. In this process, micro-adhesion of multiple SU-8 layers was also studied. A method for depositing nickel via electroless plating was also developed, tested and characterized. While no microrobots were shown to produce rotation, the final results included beams that were capable of magnetically-induced vibration when subjected to an AC …