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Relationship Between Macro And Micro Friction Coefficients Of Sandstone Structural Surface Based On Nano-Scratch Test, Shuang Zheng, Rui Yong, Shi-Gui Du, Zhi-Hai He, Zhen Zhong, Ying-Ying Zhang, Su-Gang Sui
Relationship Between Macro And Micro Friction Coefficients Of Sandstone Structural Surface Based On Nano-Scratch Test, Shuang Zheng, Rui Yong, Shi-Gui Du, Zhi-Hai He, Zhen Zhong, Ying-Ying Zhang, Su-Gang Sui
Rock and Soil Mechanics
Basic friction coefficients are important parameters affecting the shear strength of structural surface in rock masses. The basic friction coefficient determined by conventional laboratory test methods is influenced by mineral composition, temperature, and other factors. To systematically reveal the basic frictional properties of structural surfaces, the macro and micro friction coefficients of sandstone were investigated separately, and their relationship was established. First, mineral components and mechanical parameters of the sandstone were determined by X-ray diffraction and nanoindentation tests. Second, the friction coefficient in the macro scale was examined by tilt test and direct shear test, and the direct shear test …
Physical Plugging Of Lost Circulation Fractures At Microscopic Level, Chengyuan Xu, Honglin Zhang, Yili Kang, Jingyi Zhang, Yingrui Bai, Juan Zhang, Zhenjiang You
Physical Plugging Of Lost Circulation Fractures At Microscopic Level, Chengyuan Xu, Honglin Zhang, Yili Kang, Jingyi Zhang, Yingrui Bai, Juan Zhang, Zhenjiang You
Research outputs 2022 to 2026
Drilling fluid loss into formation fractures is one of the most common and costly problems encountered during the exploration and development of oil and gas resources. At present, the most extensive solution is to use physical lost circulation materials (LCMs) to form high-strength plugging zone in fractures. However, it is still unclear how the plugging is initiated and formed in the fracture. In this paper, a microscopic visualization experimental device for the formation of plugging zone is used to observe the dynamic plugging performance of spherical materials, flaky materials and fibers in fracture. Experimental results show that the formation of …
Theory, Fabrication, And Experimentation Of Phononic Crystals In Mems At Micro/Nano Scale: Engineering Of Thermal And Rf Phonons To Applications In Thermoelectrics And Microresonators, Seyedhamidreza Alaie
Theory, Fabrication, And Experimentation Of Phononic Crystals In Mems At Micro/Nano Scale: Engineering Of Thermal And Rf Phonons To Applications In Thermoelectrics And Microresonators, Seyedhamidreza Alaie
Mechanical Engineering ETDs
Phononic Crystals (PnCs) are novel materials comprised of a periodic structure of inclusions in a matrix. This periodic arrangement creates phononic bandgaps, and modifies phononic bandstructures of a material. Such a property offers promising applications at the micro and nano scales to engineer acoustic filters, high Q-factor resonators, and thermoelectric properties of materials. Studying PnCs at the micro/nano scale requires specific characterization techniques, which rely on Micro Electro Mechanical Structures (MEMS). This work focuses on the study, and characterization of PnCs using MEMS in view of their prospective applications in thermoelectric materials, microresonators and acoustic filters, and also the prospective …
Microscale Mechanical Behaviour Of Ultra-Fine-Grained Materials Processed By High-Pressure Torsion, Klaus-Dieter Liss
Microscale Mechanical Behaviour Of Ultra-Fine-Grained Materials Processed By High-Pressure Torsion, Klaus-Dieter Liss
Faculty of Engineering and Information Sciences - Papers: Part A
A special networking seminar was given by Associate Professor Megumi Kawasaki from Hanyang University, South Korea. The seminar covered microscale mechanical behaviour of ultrafine- grained materials processed by high-pressure torsion, and was co-organised by the School of Mechanical, Materials and Mechatronic Engineering (MMME), University of Wollongong and Materials Australia NSW. The event was hosted on 20 September 2016 at a sponsored networking tea by MMME.
Microscale And Fluorescence-Based Techniques/ Systems To Monitor Biological Changes In Real-Time, Manasa Paidipalli
Microscale And Fluorescence-Based Techniques/ Systems To Monitor Biological Changes In Real-Time, Manasa Paidipalli
Doctoral Dissertations
The long-term objective of this work is to develop an integrated continuous-flow microfluidic device for the analysis of genetic changes in DNA. Initially, this required the development of new techniques to simulate and then quantify DNA damage using existing laboratory instrumentation. Many analytical protocols exist for the quantification of varied types of DNA damage, which span a range of complexity and sensitivity. As an efficient alternative to the existing procedures, this work demonstrates the application of quantitative polymerase chain reaction (qPCR) and high-resolution DNA melting analysis (HRMA) to the detection and quantification of intramolecular DNA damage and/or strand breaks. These …
From Micro- To Nano-Scale: Applications Of Solid-Phase Enzymatic Reactors For Biopolymer Disassembly, Nyote J. Calixte
From Micro- To Nano-Scale: Applications Of Solid-Phase Enzymatic Reactors For Biopolymer Disassembly, Nyote J. Calixte
LSU Doctoral Dissertations
The process of immobilizing enzymes onto solid supports for bioreactions has some compelling advantages compared to their solution-based counterpart including the facile separation of enzyme from products, elimination of enzyme autodigestion, and increased enzyme stability and activity. We report in this work, the immobilization of λ-exonuclease onto poly(methylmethacrylate) (PMMA) micro- and nano-pillars populated within a fluidic devices for the micro and nanoscale on-chip digestion of double-stranded DNA. Enzyme immobilization in both studies was successfully accomplished using 3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) coupling to carboxylic acid functionalized PMMA micropillars. Our micro-scale results suggest that the reaction efficiency for the catalysis of dsDNA digestion …
Method And Apparatus For Characterizing Microscale Formability Of Thin Sheet Materials, Nasr A. Shuaib, Marwan K. Khraisheh
Method And Apparatus For Characterizing Microscale Formability Of Thin Sheet Materials, Nasr A. Shuaib, Marwan K. Khraisheh
Mechanical Engineering Faculty Patents
A method of predicting sheet formability at a microscale level includes the steps of providing a grid pattern on a test sheet, bulging the test sheet to a hemispherical shape until a crack is initiated on the surface of the test sheet, detecting the initiation of the crack, acquiring two images of the surface adjacent to the crack and calculating surface strains on the test sheet.
Fluidic Assembly At The Microscale: Progress And Prospects, Nathan B. Crane, Onursal Onen, Jose Carballo, Qi Ni, Rasim Guldiken
Fluidic Assembly At The Microscale: Progress And Prospects, Nathan B. Crane, Onursal Onen, Jose Carballo, Qi Ni, Rasim Guldiken
Faculty Publications
Assembly permits the integration of different materials and manufacturing processes to increase system functionality. It is an essential step in the fabrication of useful systems across size scales from buildings to molecules. However, at the microscale, traditional “grasp and release” assembly methods and chemically inspired self-assembly processes are less effective due to many scaling effects. Many methods have been developed for improving microscale assembly. Often these methods include fluidic forces or the use a fluidic medium in order to enhance their performance. This paper reviews basic assembly theory and modeling methods. Three basic assembly strategies (tool-directed, process-directed, and part-directed) are …
Method And Apparatus For Characterizing Microscale Formability Of Thin Sheet Materials, Nasr A. Shuaib, Marwan K. Khraisheh
Method And Apparatus For Characterizing Microscale Formability Of Thin Sheet Materials, Nasr A. Shuaib, Marwan K. Khraisheh
Mechanical Engineering Faculty Patents
A method of predicting sheet formability at a microscale level includes the steps of providing a grid pattern on a test sheet, bulging the test sheet to a hemispherical shape until a crack is initiated on the surface of the test sheet, detecting the initiation of the crack, acquiring two images of the surface adjacent to the crack and calculating surface strains on the test sheet.
A Solid State Nitrogen Gas Generating Chip And Applications For Picosatellites, Kyle Godin
A Solid State Nitrogen Gas Generating Chip And Applications For Picosatellites, Kyle Godin
Graduate Theses and Dissertations
A microscale gas generating chip has many applications; in this study, applications relating to picosatellites have been considered. Cube satellites, a type of picosatellite, are of mass around one kilogram and side length 10cm x 10cm x 10cm. Their launches are becoming more numerous since their debut ten years ago. Their low cost and deployment system makes space accessible to agencies hitherto barred from it, such as universities and small governments. However, their power, mass, and volume budget is extremely tight. A microscale gas chip could compete with other designs for attitude control devices, most not flown yet as cube …
Experimental Study Of Flow Boiling Heat Transfer And Critical Heat Flux In Microchannels, Wai Keat Kuan
Experimental Study Of Flow Boiling Heat Transfer And Critical Heat Flux In Microchannels, Wai Keat Kuan
Theses
Advancements in microprocessors and other high power electronics have resulted in increased heat dissipation from those devices. In addition, to reduce cost, the functionality of microprocessor per unit area has been increasing. The increase in functionality accompanied by reduction in chip size has caused its thermal management to be challenging. In order to dissipate the increase in heat generation, the size of conventional fin-type heat sinks has to be increased. As a result, the performance of these high heat flux generating electronics is often limited by the available cooling technology and space to accommodate the larger conventional air-cooled heat sinks. …
Design And Fabrication Of A Microscale Joule -Thomson Refrigerator, Lionel Gamini Hewavitharana
Design And Fabrication Of A Microscale Joule -Thomson Refrigerator, Lionel Gamini Hewavitharana
Doctoral Dissertations
A simple thermodynamic, heat transfer, and fluid flow model was developed for microscale Joule-Thomson refrigerators (JT devices). For a given geometry, the model predicted that the cooling capacity of the refrigerator increased with the inlet refrigerant pressure. The effectiveness of the JT device also increased with the inlet pressure, and the heat exchanger channel length. At a constant inlet pressure, the effectiveness, and the refrigeration capacity of a given JT device increased as the aspect ratio of heat exchanger channels was increased. For nitrogen refrigerant, the model predicted that it was possible to obtain approximately 250 mW of refrigeration capacity …