1,131 research outputs found
Craft so long to learn
No full textSpeech delivered by George Connor, identified by the author as "one of the 2 or 3 most signifcant speeches in my career.
Craft so long to learn
No full textSpeech delivered by George Connor, identified by the author as "one of the 2 or 3 most signifcant speeches in my career.
Jere Nash Interview with Peggy Connor
No full textInterview conducted by author Jere Nash with Peggy Connor as research for Mississippi Politics: The Struggle for Power, 1976-2006. Connor was the lead plaintiff in the case Connor v. Johnson on legislative voting districts in Mississippi. Topics covered include Connor\u27s family, background, and her participation in the civil rights movement; Fannie Lou Hamer; attempting to integrate precinct meeting and registering to vote; Mississippi Freedom Democratic Party; 1964 Democratic National Convention; Connor v. Johnson lawsuit; and civil rights demonstrations in Hattiesburg, Mississippi
Cutting'aesthetic teeth' : Flannery O'Connor's habit of art
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e ExpressãoEste trabalho foi sugerido pela afirmação de Flannery O'Connor que sua "dedicação estética" nasceu através do contato com Art and Scholasticism de Jacques Maritain. O propósito foi chegar a uma interpretação do sentido da frase. Uma investigação detalhada foi feita do conteúdo de Art and Scholasticism, posteriormente contrastada com os resultados de uma pesquisa feita em seus ensaios e suas cartas, o que revelou numerosos ecos de diversos trechos constando no texto de Maritain. Três pontos principais foram escolhidos como critérios na análise do hábito artístico de O'Connor: 1) a prática de arte implica uma luta; 2) a arte somente pode ser percebida pelos sentidos; e 3) a prática de arte exige do artista a dedicação indivisa à obra nascente. O estudo conclui que, para O'Connor, o brotar da dentição estética, através da leitura de Art and Scholasticism, significou que, ao perceber na análise da natureza da arte algo com que podia concordar, ela reconheceu tanto sua própria capacidade de tornar-se uma artista literária, quanto sua vontade de assumir a tarefa de desenvolver em sua pessoa o hábito de arte
From defect to design feature: optimising LB-PBF-induced porosity for altering tribological behaviours of cocrmo surfaces for orthopaedic applications
No full textAdditive manufacturing has expanded the design possibilities for orthopaedic implants, enabling complex geometries and patient-specific customisation that are difficult to achieve with conventional manufacturing. Among these techniques, Laser Beam Powder Bed Fusion (LB-PBF) has been widely adopted for processing metals. Cobalt-chromium-molybdenum (CoCrMo) alloys have been the standard bearing material in many designs of artificial hip joints for their high mechanical strength and wear resistance. Despite extensive work on LB-PBF mechanical properties and on the tribology of conventionally manufactured CoCrMo, the tribology of LB-PBF CoCrMo remains not well understood. Porosity is an intrinsic feature of LB-PBF, arising from the interaction of process parameters and thermal histories. In the context of articulating surfaces, LB-PBF process-induced pores represent a microstructural feature whose effects on tribological performances have yet to be fully defined. Understanding whether such features behave as defects to be eliminated or as functional surface textures with potential performance benefits requires a combined additive manufacturing-tribology approach. This thesis addresses this gap by progressing from elucidating fundamental process-structure relationships, through assessing tribological behaviours of LB-PBF CoCrMo, to demonstrating the feasibility of manufacturing bearing surfaces with spatially tailored porosity. The results demonstrate that LB-PBF process-induced porosity in CoCrMo can be systematically controlled through the combined effects of process parameters, enabling porosity levels ranging from near-dense to highly porous. Tribological evaluation showed that the effects of porosity are strongly affected by lubrication conditions: under protein-rich lubrication, friction and wear performance depend on the porosity level, whereas under water lubrication, higher porosity led to increased friction and apparent wear volume loss. The fabrication and testing of hybrid bearing surfaces with locally engineered porosity revealed that spatial porosity contrasts introduced additional complexity and increased frictional variability and wear. The outcomes provide a foundation for optimising LB-PBF processing strategies and exploring new design approaches for orthopaedic implants.Open Acces
Investigating the role of infill structures on the shape memory effect of shape memory polymers in additive manufacturing
No full textAdditive Manufacturing (AM) enables designers and engineers to embed functions into printed objects by its unique advantages. This means a product, or component, which performed a specific purpose can be embedded into another part.
One way of embedding functions in AM is through the use of Shape Memory Polymer (SMP). SMP is the material that reacts to a stimulus and changes shape. Using smart material's unique properties, 3D printed objects can be transformed following intended programmed sequences.
Another way to embed the function into 3D printed objects is through the use of Metamaterial (also called smart structure). Metamaterial uses the smartly designed internal movement to embed function and derives unique properties from smartly designed structures.
This thesis investigates the effect of infill structure on the Shape Memory Effect (SME) of SMPs. By comparing various infill structures (e.g., infill patterns and internal void), the impact on SME was explored. Previously, several studies successfully programmed SME by altering printing parameters such as infill density or filling angles. However, only limited studies were performed with Material extrusion 3D printing technology, and correlations between SME and infill structure has not fully explained yet. Therefore, this study will primarily aim to study how infill-patterns or partial parts of infill structures change SME. Various infill structures are fabricated while maintaining the same external object geometry, to explore their impact on SME. It is shown that SME can be controlled without any requirement to change materials or external geometrical parameters. This enables us to embed various SME into objects all made from the same material.Open Acces
Multi-axis and multi-material additive manufacturing of electrical traces
No full textDesign and manufacture of next generation intelligent and connected devices is an
interdisciplinary research that incorporates a range of research areas, including additive
manufacturing (AM), design, human-to-computer interaction (HCI), electrical engineering
and materials science. The subject’s diversity of influence requires the cross-pollination
of knowledge and research ideas to develop and expand its applications. Contributions
to building the next generation of intelligent and connected devices will involve enhanced
automation in design and production, mass-customised manufacturing for bespoke applications, and increased accessibility of affordable and precise fabrication tools, all of
which will be key contributors to new changes in production and delivery chain of future
connected devices.
A practical strategy toward next generation device design and manufacture lies in increasing hardware and software innovations for constructing various freeform 3D printed parts
with functionalities that can be utilised as an end use product. Such innovations could
include the following:
i) Expanded multi-functionality, multi-axis and multi-material of the AM, wherein 3D
printed parts can conduct electricity, combine various materials seamlessly and be constructed in conformal layers that the printed parts have uniform structural properties on
all surfaces formed by continuous material extrusion. A multi-axis machine could also
perform assemblies such as pick and place to fully automate the manufacturing process
of electronic objects
ii) Increased availability of parametric and automated approaches to design and computation. Multi-axis 3D printing requires complex process to generate toolpaths for controlling
the printer. New developments of the design software for structural electronics and multi-
axis toolpaths generator dedicated for AM will ease the workflow and reduce the labour
intensity involved in the chain process of design to manufacturing.Open Acces
Design and development of graphene-based knitted textile strain sensors for human motion monitoring: optimisation and challenges for real world applications
No full textIn recent years, flexible strain sensors based on textiles have been widely applied in human motion monitoring due to their lightweight, flexibility, and comfort. Textiles are characterised by their porous structure and tear resistance, making them optimal for serving as substrates for conductive materials like graphene, known for its excellent electromechanical properties and cost-effective production processes. Despite graphene's potential in textile strain sensors for human motion monitoring, challenges persist in maintaining high sensitivity over large sensing ranges and ensuring compatibility in real-world scenarios. This thesis presents a comprehensive study on developing graphene-based knitted textile strain sensors, focusing on optimising their performance for practical human motion monitoring applications.
To systematically design, analyse, and assess the application of graphene-based textile strain sensors in human motion monitoring, this thesis includes three key studies: 1) Identifying the textile design requirements for graphene-based strain sensors by analysing the characteristics of different textile materials suitable for preparing strain sensors; 2) Developing a flexible and durable graphene knitted strain sensor to cope with challenges encountered in real-world use such as washing, repetitive wearing, and sunlight exposure; 3) Investigating the integration methods of textile sensors into wearable devices, and developing a complete wearable sensing system as well as evaluating its performance in practical applications. Each study involves performance testing of the sensor, from material composition to the final integration into a complete wearable system. The findings indicate that the optimisation of textile design has potential to produce graphene-based strain sensors with high sensitivity and wide sensing ranges, capable of combining outstanding sensing performance with long-term monitoring stability and achieving comprehensive monitoring with fast, convenient integration processes. This research not only advances the state-of-the-art in strain sensing materials but also proposes a scalable manufacturing model for future industrial applications, promising widespread adoption in healthcare and athletic monitoring fields.Open Acces
Additive manufacturing: Towards alloys with spatially defined tribological properties
No full textThe tribological properties of metals produced by additive manufacturing (AM) techniques are not well understood. Recent literature has produced contradictory findings on the wear and friction performance of AM steel compared to conventionally manufactured steel. Beyond tribology, scientists and engineers observed that AM produces alloys with unconventional microstructures, in turn giving rise to unconventional properties. Furthermore, they observed that the resultant microstructure is a direct function of the AM process parameters. In this thesis, a bottom-up, experimental approach is used to uncover the complex role the AM-induced microstructure plays in the tribological response of steel (first aim of the thesis). Several tribological set-ups (reciprocating sliding, in-situ/ex-situ SEM micro-scratching, macro-scratching) and imaging techniques (SE, BSE, ECCI, EDS, EBSD, white-light interferometry) revealed a great deal of anisotropic tribological behavior (‘tribological anisotropy’) ensues from the microstructure. Dislocation density and arrangement, low-angle grain boundaries, high-angle grain boundaries, crystallographic orientation all contribute to the tribological anisotropy. Based on this knowledge, the AM process parameters were controlled to produce steel tribosurface with spatially defined microstructure design (referred to herein as ‘multigrade tribosurface’). These multigrade tribosurfaces in turn exhibit multigrade tribological properties (second aim of the thesis) not achievable via conventional manufacturing routes. In particular, it was revealed that the Taylor factor (accounting for orientational stiffness of the underlying crystal) correlates with the coefficient of friction during sliding over a wide load range. Furthermore, it was revealed that the presence of strong crystallographic texture, or lack thereof, correlates with the susceptibility to generating wear debris. The results in this thesis, by and large, explain the tribological nuances of AM alloys and demonstrate the AM technology’s potential to furthering the field of tribology.Open Acces
Investigation into adaptive slicing methodologies for additive manufacturing
No full textAdaptive slicing is a methodology used to optimise the trade-off between build-time reduction and geometric accuracy improvement in additive manufacturing (AM). It works by varying decreasing layer thickness in sections of high curvature. However, current adaptive slicing methodologies all face the difficulty of adjusting layer thickness precisely according to the variations of the model’s geometry, thereby limiting the geometric accuracy improvement.
This thesis tackles this difficulty by indicating the geometric variations of the model by evaluating the ratio of the volume of each sliced layer’s geometric deviation to the volume of its corresponding region in the digital model. This indication is accomplished because all the topological information of the corresponding region is considered in assessing the geometric deviation (volume) between each sliced layer and its corresponding region. Through having this precise indication to modify each layer thickness, this thesis aims to develop an adaptive slicing that can mitigate geometric inaccuracies (e.g. staircase effect and dimensional deviation) while balancing the build time. This slicing is evaluated using six different test models, compared with three current slicing methodologies (voxelisation-based, cusp height-based, and uniform slicing), and validated through computation and manufacturing. These validations all demonstrate that volume deviation-based slicing optimises the trade-off between build-time reduction and geometric accuracy improvement better than the other existing slicing methodologies. For example, it can reduce the build time by nearly half compared to other existing slicing methodologies assuming a similar degree of printed parts’ geometric accuracy.
The improved trade-off optimised by volume deviation-based slicing can directly benefit the AM applications in the aerospace and medical industries. This is because current research has shown geometric inaccuracies are the primary cause of reducing energy efficiency (e.g. turbine blade and wind tunnel testing models) and having failed implants (e.g. hip and cranial implants, dental prostheses). In addition to improving the geometric accuracy of AM-constructed parts, volume deviation-based slicing may also be incorporated with non-planar layer slicing. Non-planar layer slicing is designed to mitigate the mechanical anisotropy of printed parts by using curved-sliced layers. By integrating volume deviation-based slicing with non-planar layer slicing, the thickness of each curved-sliced layer can be adjusted according to the model’s geometric variations and, therefore, has a possibility of reducing the geometric inaccuracies and mechanical anisotropy simultaneously.Open Acces
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