3D modelling of Ti–6Al–4V linear friction welds

Linear friction welding (LFW) is a solid-state joining process that significantly reduces manufacturing costs when fabricating Ti–6Al–4V aircraft components. This article describes the development of a novel 3D LFW process model for joining Ti–6Al–4V. Displacement histories were taken from experiments and used as modelling inputs; herein is the novelty of the approach, which resulted in decreased computational time and memory storage requirements. In general, the models captured the experimental weld phenomena and showed that the thermo-mechanically affected zone and interface temperature are reduced when the workpieces are oscillated along the shorter of the two interface contact dimensions. Moreover, the models showed that unbonded regions occur at the corners of the weld interface, which are eliminated by increasing the burn-off

Microstructure of interpass rolled wire + arc additive manufacturing Ti-6Al-4V components

Mechanical property anisotropy is one of the issues that are limiting the industrial adoption of additive manufacturing (AM) Ti-6Al-4V components. To improve the deposits’ microstructure, the effect of high-pressure interpass rolling was evaluated, and a flat and a profiled roller were compared. The microstructure was changed from large columnar prior beta grains that traversed the component to equiaxed grains that were between 56 and 139 μm in size. The repetitive variation in Widmanstätten alpha lamellae size was retained; however, with rolling, the overall size was reduced. A “fundamental study” was used to gain insight into the microstructural changes that occurred due to the combination of deformation and deposition. High-pressure interpass rolling can overcome many of the shortcomings of AM, potentially aiding industrial implementation of the process.EPSRC, AirBu

Investigation of low current gas tungsten arc welding using split anode calorimetry

Most previous split anode calorimetry research has applied high weld currents which exhibit pseudo Gaussian distributions of arc current and power density. In this paper we investigate low current arcs and show that both the current and power distributions have minima in the centre – varying significantly from the expected Gaussian profile. This was postulated due to the formation of the arc with the copper anode and the tungsten cathode. Furthermore, a number of parameters were varied including the step size between measurements, anode thickness and anode surface condition as well as cathode type and tip geometry. The step size between measurements significantly influenced the distribution profile and the anode thickness needed to be above 7 mm to obtain consistent results

Racing to Equality: A Critique of Female Exclusion in Motorsports

I wrote this article as an assignment for my ENG 198 class. We were originally assigned to establish a research-supported argument on the subject of gender, choosing the direction we wanted to take. As a fan of all types of motorsports, I noticed a lack of competition among males and females on the professional level. There are numerous examples of talented women in the sport, and I believed their voices needed to be heard. This inspired me to develop this piece of writing. After multiple drafts, peer reviews, and personal critiques by my professor, I was able to create an effective research paper that I feel wholly addresses the issue

Reducing Your Water Footprint: An Activity Packet On Water Conservation For Young Children

This curriculum guide capstone sought to answer the question of, how can young children reduce their water footprint? In order to achieve this, it was determined that the form of an activity packet focused on water conservation would allow for young children to be introduced to, and habitually practice, water conservation methods. The author researched child development theories that were most effective in educating the widest possible audience of children while dually causing the instilling of environmental values; the science of habits was also examined. Additionally, the author examined preexisting activity packets and curriculums regarding the environment that had been found proven successful. All of these areas served as the foundation for which the individualized activity packet was then built upon; in turn, an activity packet on water conservation was created that successfully allowed for young children to reduce their water footprint

Modelling of Friction Stir Welding

This thesis investigates the modelling of friction stir welding (FSW). FSW is a relatively new welding process where a rotating non-consumable tool is used to join two materials through high temperature deformation. The aim of the thesis is the development of a numerical model to improve process understanding and to assist in the design of new tools. The early part of the thesis describes the process, defines the modelling problem and describes why a computational fluid dynamics package (FLUENT) was selected for the subsequent work. A systematic series of friction stir welding experiments in 7075 aluminium alloy, used to provide validation data for a numerical model of the process, are described in chapter 2. The trials examined how the welding conditions and tool type affected the weld temperature and heat input. From this data a thermal model of the welds was developed that included the convective heat flow due to material mixing. Chapters 3 to 6 describe the model development, from a preliminary model of a standard tool, to a detailed analysis of 2 dimensional profiles incorporating a novel slip boundary condition, and finally to a full 3 dimensional model of a new tool design, including material slip. The preliminary model with a standard tool assumed that the material stuck to the tool surface and included features such as the tool tilt, heat generation and heat flow. The model captured many of the real process characteristics, but gave poor predictions of the welding forces and heat generation. This identified the need for a more complex treatment of the tool-material interface that allowed material slip. The slip model was first implemented in a 2 dimensional study of flow around profiled tooling (chapter 4). This enabled a first order visualisation of the flow and the quantitative comparison of different 2 dimensional pin profiles. In chapter 5 an optimised 2 dimensional pin profile was determined by selecting the shape that minimised the traversing force. Two prototype tools based on this profile were manufactured: the plain 'Trivex™' and the threaded 'MX-Trivex™'. These were tested against a conventional 'MX-Triflute™' tool with the results showing that the traversing force was reduced by 18-25%. Chapter 6 describes 3 dimensional models of the 'Trivex™' and 'Triflute™' tools, which extended the slip model to 3 dimensions. The model correctly predicted that the Trivex™ tool had lower traversing and down forces than its Triflute™ counterpart, as observed experimentally. The thesis successfully demonstrates the application of fluid dynamics modelling to friction stir welding, enhancing visualisation of the flow, and guiding the development of new tooling

ClearView Church: An Online Brand Management Model for Nonprofits

This project aims to provide specific recommendations to ClearView Church, and by extension nonprofits in similar situations, on how to strengthen their online presence. The recommendations are formed through in depth research into ClearView’s resources, goals and requirements as well as calling upon my expertise and experience in the technical and communications sides of the nonprofit field. Through multiple interviews with church staff and members, I determined an overarching goal of sharing the warm, welcoming personality of the church with young families in the surrounding community. However, this goal was not guiding their online outreach efforts and therefore needed to be re-evaluated. The first stage of my project acted as an audit of the church’s online presence. I then began the process of designing and coding the website, researching content management systems, launching the website and providing social media recommendations to ClearView, all with the outreach goal and previous successful aspects in mind. Each step in this process was submitted to ClearView staff for review and approval before the next step could begin. Input and approval from ClearView, who acted as the client for this project, was crucial as the church will be in charge of maintaining and updating the website and social media platforms in the future. The final website, as with any client, has to meet their expectations and be feasibly maintained after delivery. In addition, the recommendations contained in this document not only act as a guide for their implementation, but also a model for similar nonprofit organizations

A model for assessing the risk of human trafficking on a local level

Title from PDF of title page (University of Missouri--Columbia, viewed on September 6, 2013).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Thesis advisor: Dr. Matthew FoulkesIncludes bibliographical references.M.A. University of Missouri--Columbia 2013.Dissertations, Academic -- University of Missouri--Columbia -- Geography."May 2013"Human trafficking is a human rights violation that is difficult to quantify. Models for estimating the number of victims of trafficking presented by previous researchers depend on inconsistent, poor quality data. As an intermediate step to help current efforts by nonprofits to combat human trafficking, this project presents a model that is not dependent on quantitative data specific to human trafficking, but rather profiles the risk of human trafficking at the local level through causative factors. Businesses, indicated by the literature, were weighted based on the presence of characteristics that increase the likelihood of trafficking in persons. The mean risk was calculated by census tract to reveal the multiplicity of risk levels in both rural and urban settings. Results indicate that labor trafficking may be a more diffuse problem in Missouri than sex trafficking. Additionally, spatial patterns of risk remained largely the same regardless of adjustments made to the model

Selecting and implementing leading edge technology services: Library as partner in the innovation ecosystem

The practice of libraries – and with it, librarianship – continues to evolve. New technology and services are fundamental to library support of innovation and creativity; deciding which technologies and/or services to implement can be less clear. The overlap of design thinking with best practices of emerging technology and libraries offers a practical approach: real-world examples of success and failure reveal the outlines of an emerging framework for improved selection and implementation of leading-edge technology in the library environment. Novel services and technologies offered by a library that is part makerspace, part accelerator, and full partner in the innovation ecosystem of the university are shared, offering simple steps and insight that can increase the likelihood of successful selection and implementation. Revitalized spaces of the library become a natural hotbed for open innovation; enhanced depth of learning, creativity, and increased opportunities for successful tech transfer appear to be a natural result