Use of Orthogonal Arrays for Efficient Evaluation of Geometric Designs for Reducing Vibration of a Non-Pneumatic Wheel During High-Speed Rolling

During high speed rolling of a non-pneumatic wheel, vibration may be produced by the interaction of collapsible spokes with a shear deformable ring as they enter the contact region, buckle and then snap back into a state of tension. In the present work, a 2D planar finite element model with geometric nonlinearity and explicit time-stepping is used to simulate rolling of the non-pneumatic wheel. Vibration characteristics are measured from the FFT frequency spectrum of the time-signals of perpendicular distance of marker nodes from the virtual plane of the spoke, thickness change in the ring between spokes, and ground reaction forces. Both maximum peak amplitudes and RMS measures are considered as measures of vibration. In the present work, a systematic study of the effects of six key geometric design parameters is presented using Orthogonal Arrays. Orthogonal Arrays are part of a design process method developed by Taguchi which provides an efficient way to determine the effects of variable levels and a guide to optimal combinations of design variables. Two complementary Orthogonal Arrays are evaluated. The first is the L8 orthogonal array which considers the six geometric design variables evaluated at lower and higher limiting values for a total of eight experiments defined by statistically efficient variable combinations. Based on the results from the L8 orthogonal array, a second L9 orthogonal array experiment evaluates the nonlinear effects in the four parameters of greatest interest, (a) spoke length, (b) spoke curvature, (c) spoke thickness, and (d) shear beam thickness. The L9 array consists of nine experiments with efficient combinations of low, intermediate, and high value levels. Results from the Orthogonal Array experiments were used to find combinations of parameters which significantly reduce peak and RMS amplitudes, and suggest which variables have the greatest effect on vibration amplitudes. The results of orthogonal arrays indicate that spoke length and spoke curvature were the most influential parameters on the amplitude of vibration for all three vibration measures. The optimal configuration predicted for these two parameters is a wheel with short spokes with large curvature. The order of influence and optimal levels of the other four variables varies according to the measure of vibration. The results show that there was effectively no interaction between spoke length and spoke thickness. However there are interactions between other variables in the system, and this interaction is stronger when non-linear variable levels were considered from the L9-array. Geometries are presented that minimize vibration for each source, and an optimal geometry is suggested that significantly reduces vibration for all measures of vibration considered. A study of natural frequency and mode shapes extracted from the operational state of the system suggest that geometries with high amplitude peaks in the FFT spectrum for spoke vibration show a correlation with spoke vibration mode shapes. For other geometries, spoke vibration amplitude peaks coincided with ring flower-pedal modes

Remembering Tin Town: identifying and valuing Aboriginal reserve sites of New South wales

Researchers of Indigenous places in Australia have written extensively about many missions, reserves and stations. Their discoveries have provided solid foundations for further studies of other forgotten places, similar to Tin Town, Coonamble, New South Wales, the focus of this study and the primary location of my research. The project engages on a personal level: it uses autoethnography to explore my sense of identity, connection to Country, experience of racism and cultural pride through truth telling. There is a mistaken belief that the church, government and land holders who directed missions, reserves and stations had done so in a method that was acceptable to Indigenous people. The project has located sources of information that give an alternate version of Indigenous missions, reserves and stations by concentrating on one forgotten place, Tin Town. I am very thankful for its existence because its story is central to this historical dialogue of truth telling. Other known and forgotten places relevant to this autoethnography are identified and described. Recognition bestows on them an unprejudiced place in Indigenous history. After identifying Tin Town and surveying the field of available resources, I uncover the untold, and sometimes hidden, truths behind what forced Indigenous people to the segregated areas. Missions, reserves and stations became the final refuge for our people, where communities and families endured poverty, racism and neglect. They suffered in third world living conditions - makeshift dwellings put together with scraps of materials to form a home for themselves, their old people and their children. My research shows that not all segregated areas were safe havens; mistreatment of Indigenous people was, in most cases, no different whether they were placed on missions, reserves or stations. There are no residual signs showing the presence of most sites, so it is important to acknowledge them, for they are markers on our story line. Most have been destroyed in the attempt to erase any evidence of their existence and to counter claims of their existence of Country ownership. At present, governmental records only acknowledge Indigenous placement areas that still show the structures of buildings, built by previous governments, churches and pastoralists, rather than Aboriginal people’s ongoing use of and connection to the land. At the heart of my thesis is the chapter in which I truth tell parts of my family’s story of resilience and survival. I validate Indigenous families who have suffered loss of Country, but still fight to rebuild their culture. My personal journey has unearthed historical writings about my ancestry and my connection to Country. Apart from self-discovery, my hope is that other Indigenous people will find themselves in what I have researched and written, so I also explore similar places to Tin Town where those who were marginalised, like my family, survived and rebuilt community. I hope a broader audience, Indigenous and non-Indigenous, will walk the walk through Country that I have experienced. The dissertation applies historical methodology as the clearest method to identify and value Aboriginal reserve sites of New South Wales. They are investigated by probing into their historical past and searching for what little evidence there is for these known and unknown places (except in the memories and stories of the local people). Autoethnography allows a voice to personal experiences with the aim of increasing sociological interpretation. I explore the relationship between both methodologies and show that bringing these styles together has established greater insight. I am writing from an Indigenous perspective, not from a Western cultural viewpoint. However, I hope to achieve understanding, balance and acceptance in both cultures to heal, forgive and grow. The exploration of one forgotten area and similar ones will contribute to recognition and respect for Indigenous placement areas not currently accounted for

The preparation and thermal decomposition of selected pyrazolines

Thesis (Ph.D.)--Boston UniversityThe reaction of diazoalkanes with a,p-unsaturated esters, amides, nitriles, ketones, and nitro compounds is known to furnish negatively substituted pyrazolines. When the alpha carbon atom of the a,p-unsaturated compound is bonded to a group other than hydrogen the delta- or azo type pyrazoline is obtained. The primary objective of the present work was the extension of this synthetic method to the preparation of new types of 61- pyrazolines which would posses certain desired structural features. In particular it "'as of interest to prepare a series of negatively substituted 61-pyrazolines having centers of unsaturation in the substituent groups, and to synthesize a number of negatively substituted dipyrazolines. The selective addition of one equivalent of diazomethane to diolefinic esters, which had one activated and one unactivated double bond, was realized. This high yield process made available a new series of pyrazolines having unsaturation in substituent groups. Among the compounds prepared were: vinyl 3-methyl-61-pyrazoline-3-carboxylate, allyl 3- methyl-61-pyrazoline-3-carboxylate, allyl 3,4-dimethyl-61- pyrazoline-3-carboxylate, vinyl 3,4-dimethyl-61-pyrazoline-3- carboxylate, vinyl 4-methyl-62-pyrazoline-3-carboxylate, methyl 4-phenyl-5-allyl-62-pyrazoline-5-carboxylate, and 4-phenyl- 5-allyl-6 2-pyrazoline-5-carboxylic acid. [TRUNCATED

The preparation and thermal decomposition of selected pyrazolines

Thesis (Ph.D.)--Boston UniversityThe reaction of diazoalkanes with a,p-unsaturated esters, amides, nitriles, ketones, and nitro compounds is known to furnish negatively substituted pyrazolines. When the alpha carbon atom of the a,p-unsaturated compound is bonded to a group other than hydrogen the delta- or azo type pyrazoline is obtained. The primary objective of the present work was the extension of this synthetic method to the preparation of new types of 61- pyrazolines which would posses certain desired structural features. In particular it "'as of interest to prepare a series of negatively substituted 61-pyrazolines having centers of unsaturation in the substituent groups, and to synthesize a number of negatively substituted dipyrazolines. The selective addition of one equivalent of diazomethane to diolefinic esters, which had one activated and one unactivated double bond, was realized. This high yield process made available a new series of pyrazolines having unsaturation in substituent groups. Among the compounds prepared were: vinyl 3-methyl-61-pyrazoline-3-carboxylate, allyl 3- methyl-61-pyrazoline-3-carboxylate, allyl 3,4-dimethyl-61- pyrazoline-3-carboxylate, vinyl 3,4-dimethyl-61-pyrazoline-3- carboxylate, vinyl 4-methyl-62-pyrazoline-3-carboxylate, methyl 4-phenyl-5-allyl-62-pyrazoline-5-carboxylate, and 4-phenyl- 5-allyl-6 2-pyrazoline-5-carboxylic acid. [TRUNCATED

The use of monotheism in the shaping of Christian identities vis-à-vis Judaism in the second century

This thesis argues that early Christians actively engaged rhetoric and symbols of monotheism in diverse literary strategies as an ideological tool for resisting, repositioning, and rereading Judaism in order to shape their own collective identity from 100 to 200 CE (ch. 1). Belief and confession of one God provides an important basis for social comparison between Jews and Christians because it represents a fundamental Jewish identity marker also shared by Christians (ch. 2). A survey of divine unity and uniqueness rhetoric in early Christian literature revealed three broad trajectories in which monotheistic motifs assumed significance in shaping Christian literature and thereby the production of "Christianness" itself. This thesis examines specific moments in each trajectory that highlight particularly well the functionality of monotheism in the process of forming Christianness relative to Judaism.Ignatius of Antioch provides the first example (ch. 3). The literary shaping of Philadelphians and Magnesians reveals that for Ignatius what fundamentally distinguished "Judaism" and "Christianism" was not monotheism but their respective response to the revelation of God through Jesus in the gospel. Monotheism was not a tool for classifying difference but a powerful weapon for resisting threatening Jewish influence within the Christian church. Only as an element of resistance brought to bear on an already established "Judaism"-"Christianism" divide did monotheism represent, reflexively and secondarily, a means of shaping Christian identity.Another trajectory overtly utilised "knowledge" of the one God as primary criterion for indexing sameness and difference between Christianity, Judaism, and other groups (ch. 4). Kerygma Petrou and Aristides' Apology employ such monotheistic classification strategies to situate Christianity in a global framework alongside other religious and/or ethnic collectivities. Both texts locate the "newness" of Christianity alongside the more well-known status of Jews. In so doing, they effectively reposition Judaism within the global framework of religious and ethnic groups to clarify and legitimate the meaning of belonging to Christian identity.Some Christians employed "two powers" hermeneutic strategies to reinterpret Jewish scriptural traditions of exclusivist monotheism by insinuating into scripture a second figure, Jesus, alongside the one God (ch. 5). Aristo's Disputation of Jason and Papiscus and Justin's Dialogue demonstrate awareness that the scriptures are shared intellectual property and the proper locus for Christian-Jewish debate. "Two powers" interpretations thus reflect conscious attempts to reread Jewish monotheistic textual traditions in a new way. Through them an entire reconstruction of the symbolic universe of monotheism can take place in explicitly Christian terms.These diverse strategies reveal a complex network of early Christian literary production that used monotheistic symbols and rhetoric as an implement to resist, reposition, and reread Judaism, thereby producing distinctly Christian identities (ch. 6)

The preparation and properties of disubstituted ethylenediamine-diacetic acids.

Thesis (M.A.)--Boston UniversityThe exceptionally stable metallic complexes formed by triglycine, ethylenediamine-tetraacetic acid, and other polycarboxylic amino acids have recently been the subject of much study. These complexes are frequently water-soluble, highly colored, and only slightly dissociated. In many cases, solubility in non-polar organic solvents has been noted. [TRUNCATED

Mars transportation system

The University of Minnesota Advanced Space Design Program has developed a sample Mars exploration scenario. The purpose of the design project is to enhance NASA and university interaction, to provide fresh ideas to NASA, and to provide real world design problems to engineering students. The Mars Transportation System in this paper is designed to transport a crew of six astronauts to the Martian surface and return them to Low Earth Orbit (LEO) starting in the year 2016. The proposed vehicle features such advanced technologies as nuclear propulsion, nuclear power generation, and aerobraking. Three missions are planned. Orbital trajectories are of the conjunction class with an inbound Venus swingby providing a 60-day surface stay at Mars and an average total trip time of 520 days

An Implementation of the Generalized Basis Reduction Algorithm for Integer Programming

In recent years many advances have been made in solution techniques for specially structured 0–1 integer programming problems. In contrast, very little progress has been made on solving general (mixed integer) problems. This, of course, is not true when viewed from the theoretical side: Lenstra (1981) made a major breakthrough, obtaining a polynomial-time algorithm when the number of integer variables is fixed. We discuss a practical implementation of a Lenstra-like algorithm, based on the generalized basis reduction method of Lovasz and Scarf (1988). This method allows us to avoid the ellipsoidal approximations required in Lenstra’s algorithm. We report on the solution of a number of small (but difficult) examples, up to 100 integer variables. Our computer code uses the linear programming optimizer CPlex as a subroutine to solve the linear programming problems that arise