Simultaneous cutting of two separate sheets using plasma and parameters optimisation

This thesis investigates on the ability of using plasma technique for cutting simultaneously two parallel thin layers at different gap distances. Previous research emphasised that plasma cutting can be optimised to improve the quality and reduce phenomena. The investigation performed previously was made primarily in two-dimensional cutting plan. However, there is a lack of publication and research regarding optimisation of a three-dimensional structure cutting. This current work would help engineers to understand the practicability of thermal cutting such as plasma to process zones in the vehicle chassis similar to box sections or double layered areas. This research is aimed at wheelchair accessible vehicle converters that performs modifications in the chassis floor. This work is part of the engineering doctorate program. The research questions raised of this study lie primarily on assessing the possibility of simultaneous cutting of a double sheet (separated with an air distance) using plasma, expressly examining the possibility to reuse the energy heat exiting the first sheet’s kerf to perform a cut on the second layer. In addition, optimising the double sheets cutting, analysing the effect of the heat on thin material and reduce the resulting phenomena to their lower level (mainly surface deformation and heat affected zones). Lastly, assess the relationship strength between the parameters and the quality. Experiments were performed in four progressive phases. The first step was made to test the suitability of the plasma to process single thin sheets of 0.6 mm thick. This step was required to analyse the impact of the heat on the surface deformation and then optimise the cutting to improve the quality. The second phase of the tests were performed to verify the plasma ability to process a 3D-Structure such as double layered zones. The third phase of test was made to assess the cutting parameters suitable to process two layers simultaneously at a fixed gap 20 mm. These parameters were used as a reference for the following stage. The fourth phase was performed to optimise the double sheets structure cutting process (separated with an air distance) and minimise the impact of the heat generated during the plasma cutting on the top sheet. The Hypothesis of re-using the heat was tested and proven true, it is possible to re-employ the heat energy exiting the kerf to perform another cut. The tests showed that there was a considerable heat impact on the surface. However, this can be controlled and reduced. Cutting two sheets simultaneously may result to an offset between the top and bottom edge of the cut. Optimisation using the DOE based Taguchi approach resulted to an improvement in quality and the regression analysis showed a good fit of the models constructed, none of the values measured were outside the interval of prediction. Final tests were performed on a vehicle chassis and the results showed that a good automation can reduce the cutting process by approximatively 40min compared to manual cutting.This thesis investigates on the ability of using plasma technique for cutting simultaneously two parallel thin layers at different gap distances. Previous research emphasised that plasma cutting can be optimised to improve the quality and reduce phenomena. The investigation performed previously was made primarily in two-dimensional cutting plan. However, there is a lack of publication and research regarding optimisation of a three-dimensional structure cutting. This current work would help engineers to understand the practicability of thermal cutting such as plasma to process zones in the vehicle chassis similar to box sections or double layered areas. This research is aimed at wheelchair accessible vehicle converters that performs modifications in the chassis floor. This work is part of the engineering doctorate program. The research questions raised of this study lie primarily on assessing the possibility of simultaneous cutting of a double sheet (separated with an air distance) using plasma, expressly examining the possibility to reuse the energy heat exiting the first sheet’s kerf to perform a cut on the second layer. In addition, optimising the double sheets cutting, analysing the effect of the heat on thin material and reduce the resulting phenomena to their lower level (mainly surface deformation and heat affected zones). Lastly, assess the relationship strength between the parameters and the quality. Experiments were performed in four progressive phases. The first step was made to test the suitability of the plasma to process single thin sheets of 0.6 mm thick. This step was required to analyse the impact of the heat on the surface deformation and then optimise the cutting to improve the quality. The second phase of the tests were performed to verify the plasma ability to process a 3D-Structure such as double layered zones. The third phase of test was made to assess the cutting parameters suitable to process two layers simultaneously at a fixed gap 20 mm. These parameters were used as a reference for the following stage. The fourth phase was performed to optimise the double sheets structure cutting process (separated with an air distance) and minimise the impact of the heat generated during the plasma cutting on the top sheet. The Hypothesis of re-using the heat was tested and proven true, it is possible to re-employ the heat energy exiting the kerf to perform another cut. The tests showed that there was a considerable heat impact on the surface. However, this can be controlled and reduced. Cutting two sheets simultaneously may result to an offset between the top and bottom edge of the cut. Optimisation using the DOE based Taguchi approach resulted to an improvement in quality and the regression analysis showed a good fit of the models constructed, none of the values measured were outside the interval of prediction. Final tests were performed on a vehicle chassis and the results showed that a good automation can reduce the cutting process by approximatively 40min compared to manual cutting

British Literature I: Middle Ages to the Eighteenth Century and Neoclassicism

The University of North Georgia Press and Affordable Learning Georgia bring you British Literature I: From the Middle Ages to Neoclassicism and the Eighteenth Century. Featuring over 50 authors and full texts of their works, this anthology follows the shift of monarchic to parliamentarian rule in Britain, and the heroic epic to the more egalitarian novel as genre. Features: Original introductions to The Middle Ages; The Sixteenth Century: The Tudor Age; The Seventeenth Century: The Age of Revolution; and Neoclassicism and the Eighteenth Century Over 100 historical images Instructional Design, including Reading and Review Questions and Key Terms Forthcoming ancillary with open-enabled pedagogy, allowing readers to contribute to the project This textbook is an Open Access Resource. It can be reused, remixed, and reedited freely without seeking permission. Accessible files with optical character recognition (OCR) and auto-tagging provided by the Center for Inclusive Design and Innovation.https://oer.galileo.usg.edu/english-textbooks/1017/thumbnail.jp

Analytical approaches to the manufacture and use of bone artifacts in prehistory

Mesolithic and Neolithic bone artifacts were analyzed with the aim of contributing knowledge regarding technological achievements, food procurement and processing, personal adornment and other aspects of social behavior. Part I presents the methodology involving the integration of data obtained through experimental replication, surface traces, metric analysis, ethnographic analogy, and archaeological context. Replicative experiments were performed to reconstruct manufacturing techniques and test functional hypotheses. Surficial topography was examined using a scanning electron microscope for the identification of manufacturing and use traces. Five key measurements were devised for evaluating gross morphology and working surfaces of artifacts. Where applicable, ethnographic analogy was employed as a source for hypotheses about artifact function. Archaeological context was studied to reveal distributional and associational patterns that might contribute evidence pertaining to the use of bone artifacts and their temporal development. Emphasis was placed on comparing data derived from the various methods to determine whether the y supported or refuted one another. Interpretations were formulated on the basis of documented patterns rather than isolated events and, whenever possible, from multiple analytical techniques. Part II demonstrates the general applicability of these methodological approaches through three case studies selected to maximize diversity of cultural affiliation, environmental conditions, temporal duration, preservational factors, and sample size. The first case study is a large, well-preserved collection from the Mogollon-Pueblo village of Point of Pines in the American Southwest. The assemblage is derived from a settlement of brief duration situated in a prairie environment. The second is a medium-sized collection from Tell Abu Hureyra in northern Syria with a long sequence from the Mesolithic through Ceramic Neolithic. The third case study consists of two small samples from Ulu Leang and Leang Burung, rock shelters in Indonesia which offer an interesting contrast in settlement t ype and environment from the two open air sites