A theoretical and experimental investigation into the use of the corrugated circular waveguide as a feeder and radiator for microwave antennas is described. Because corrugated waveguide feeders are ·overmoded, the effects on the propagation and radiation characteristics of mode conversion due to bends are investigated. New methods of providing higher order mode suppression are described, and substantiated by experimental results using resonant cavity and transmission line methods. The cross-polarisation properties of corrugated waveguides are shown to be intrinsically superior to those of smooth wall waveguides when the waveguide wall suffers elliptical deformation. As an alternative to the problems involved in overmoded operation a design of corrugated circular waveguide for HEll mono-mode operation, which still exhibits an attenuation advantage, is developed. The radiated co-polar and cross-polar performance of corrugated circular waveguides and narrow flare-angle corrugated concial horns are studied both experimentally and theoretically using a more accurate analysis than attempted by previous authors. Design curves for optimum cross-polar radiation performance are presented and a new method of improving the cross-polarisation performance of these structures is theoreti6ally predicted, and experimentally verifjed.

Ribbed steel pipes made of Type 2 aluminized steel are commonly used for culvert pipes for highway drainage. Typically aluminized steel pipes have shown good durability and are expected to have long service life, e.g. 75 years; also, they are used in a wide variety of soil and water conditions. However, early corrosion of aluminized steel pipes has been recently observed in some inland locations. Initial observations showed severe corrosion in forms of pits, both along the ribs and at the nearby flat portions of the pipes. It is critical to determine the cause of early deterioration and establish methods of durability prediction. The possibility of unusual environmental conditions is being investigated elsewhere, but this research focuses on possible mechanical factors aggravating corrosion, since it is prevalent near pipe rib deformations. While forming the rib bends in the pipe, the outer bend surface is exposed to extreme tensile stresses which would cause small coating cracks (microfissures) exposing base metal. Those may lead to early corrosion as galvanic protection from the surrounding aluminum may not be sufficient under certain environments. Electrochemical impedance spectroscopy was used to measure corrosion rate of both formed and flat aluminized steel samples in simulated natural waters. Initial findings show that specimens formed by spherical indentation were susceptible to early corrosion development in moderately aggressive simulated natural water, but not in a more benign, precipitating simulated natural water solution.

Deep-corrugated steel culverts (with a corrugation wavelength of 400mm and amplitude of 150mm) can be used as an effective alternative for short-span bridges. Current design methods are typically based on two-dimensional finite element analysis. This thesis reports results from three-dimensional finite element analysis, with explicit modelling of the geometry of the corrugated plates (called corrugated analyses) and employing the orthotropic shell theory (called orthotropic analyses), for a specific box culvert having a 10 m span and 2.4 m rise. The results were compared to previously reported experimental data where a specific large span box culvert was tested under controlled laboratory conditions. The behaviour of the box culvert under small vertical displacement without any soil support was modelled to isolate the structure response. The box culvert was also modelled when subject to fully loaded dump truck, and when loaded using a tandem axle frame to service and ultimate loads. Both corrugated and orthotropic analyses successfully captured the response of the box culvert when backfilled and loaded using dump truck and axle frame loading. It was found that the orthotropic model overestimated the culvert stiffness at the ultimate limit state, but provided effective estimates of response up to the factored design loads. The corrugated model with geometric nonlinearity was required to capture the real behaviour of the corrugated plates up to the ultimate limit state. New insight into the failure mechanisms of the box culvert were provided by the corrugated model analysis. A parametric study was then performed for 86 different long-span box and arch culverts, examining live load spreading in the axial direction, number of loaded lanes, design truck position, culvert geometry, plate thickness, and the existence of pavement. The results were then compared to the moment and thrust equations in the 2006 Canadian Highway Bridge Design Code (CHBDC) to check the performance of the current design equations. CHBDC equations overestimated the earth and live load bending moments, and did not give the correct trend for different spans. CHBDC thrust equations were found to underestimate the earth and live load thrust values for arch culverts. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2011-04-26 15:33:45.103

Full-scale simulated live load tests were conducted in a controlled laboratory setting using a single-axle frame on 600-mm-inner-diameter reinforced concrete pipe (RCP) and corrugated steel pipe (CSP) when buried in dense, well-graded sand and gravel. Measurements of the RCP at nominal and working forces and beyond are reported for 0.3, 0.6 and 0.9 m of soil cover above the pipe crown. The RCP experienced no cracking when buried at 0.3 m under nominal and working CL-625 and CL-800 single-axle design loads. At these loads, the vertical contraction of the pipe diameter was less than 0.08 and 0.10 mm and the largest tensile strains in the pipe were 75 and 100 με (50-60% of the cracking strain), respectively. A 0.15 (±0.05)-mm-wide axial crack developed at the inner crown in the presence of a 6 kNm/m circumferential bending moment (70% of the theoretical ultimate moment capacity) at the fully factored CL-625 load. This crack did not propagate or widen from 3 series of cyclic load-unload tests. At 1300 kN of applied load the change in pipe diameter was less than 3.5 mm. Increasing soil cover from 0.3 to 0.6 to 0.9 m reduced the circumferential crown bending moment from 6.0 to 3.9 to 2.1 kNm/m, respectively, at 400 kN of axle load. A 1.6- and a 2.8-mm-thick CSP were also subjected to axle loading. No yielding or limit states occurred in the 1.6-mm-thick CSP when buried 0.9-m-deep. However, at 0.6 m of cover a 300 kN axle load caused local yielding at the pipe crown. Increasing soil cover from 0.6 to 0.9 m decreased the vertical diameter change from -3.0 to -1.2 mm and the crown bending moment from 0.7 to 0.2 kNm/m (75% and 20% of the yield moment), respectively, at a 250 kN axle load. Deflections of the thicker CSP were less than the thinner pipe below the CL-625 single-axle load, however further increases in applied load produced a greater response in the thicker pipe, likely due to a haunch support issue. Shallow axle loading produced a greater 3-dimensional response and a larger bending effect in both CSPs. / Thesis (Master, Civil Engineering) -- Queen's University, 2012-05-06 15:10:12.754

In a recent study, an environment-friendly material, corrugated cardboard, was used as a building block for the vibration isolator with a preliminary study. The present thesis was motivated to advance technology for improving the design of such a corrugated cardboard vibration isolator with a focus on the modeling of its stiffness and damping. In particular, this study has performed the following works: (1) improving the FE (finite element) model of the stiffness of the corrugated cardboards by more accurately identifying the material parameters in the cardboard material constitutive equation; (2) analyzing the effect of the error in geometry of the corrugated cardboards in the FE model; (3) developing the Rayleigh damping model of the corrugated cardboards and evaluating its accuracy. Several conclusions were drawn from this study: (1) the parameter identification procedure based on the inverse analysis is feasible for improving the accuracy of the model of the stiffness of the cardboard. (2) The FE model of the cardboards with a greater in-plane geometrical deflection has less vertical compressive stiffness. The geometrical deflections of the corrugated cardboards also change the condition of the contact friction stress and the compressive deformation. (3) Rayleigh damping model is accurate enough for calculating the damping of the corrugated cardboards. The contributions of the thesis include: (1) provision of a more accurate model for the compressive stiffness the corrugated cardboards, (2) finding that the friction between the cardboard and the vibrator and the geometrical error of the cardboards have a significant influence over the accuracy of the FE model, (3) finding that in practice the foregoing influence can significantly degraded the performance of the cardboards as a vibrator isolator, and (4) provision of a model for the compressive damping of the corrugated cardboards.

Thesis (M.S.)--Ohio University, June, 2004. / Title from PDF t.p. Includes bibliographical references (leaves 78-80).

This research explores the relationship between social identity, artifact style, and communities of practice in the late prehispanic U.S. Southwest, focusing on how domestic, utilitarian objects and contexts both shape and reflect social identities. During the A.D. 1200s and 1300s, large-scale migration and aggregation occurred over much of the U.S. Southwest, bringing diverse individual and community identities into contact and, potentially, conflict. Within this social context, this research focused on clarifying the relationship between social identities and utilitarian objects and domestic contexts, and how this relationship can elucidate the social history of a community. These issues were explored through analysis of corrugated utilitarian pottery from the sites of the Homol’ovi Settlement Cluster (HSC), a community of seven villages in northeastern Arizona occupied from around 1260 through 1400. The social organization of corrugated pottery production in the HSC was approached from several angles. To identify the number and nature of the ceramic manufacturing communities present during the Pueblo IV occupation of the Homol’ovi area, sherds were submitted for instrumental neutron activation analysis and petrographic analysis. The results of the compositional analyses indicate that ceramic production groups in the Homol’ovi area were not primarily distinguished by access to specific raw material resources. What differentiation there is within the raw materials used by Homol’ovi potters appears to have been determined primarily by village, with the residents of a few villages preferring to use specific clay or temper sources. Both locally produced pottery and ceramics imported into the Homol’ovi area were incorporated into a typological and stylistic analysis. This analysis found evidence of two different production styles in the corrugated pottery assemblage. One appears stylistically similar to pottery produced in areas to the north around the Hopi Mesas; the other appears to be more akin to stylistic traditions practiced in the Puerco area and in the Chevelon drainage. This diversity suggests the presence of multiple immigrant communities co-residing within the HSC. This social diversity is not reflected in the decorated ceramic tradition of the HSC, which largely conforms to the ceramic traditions of the Hopi Mesas. Interrogating the disjuncture in the identities embodied through different categories of material culture, used in different social contexts, provides a framework through which to explore the complex social relationships that characterized Pueblo IV villages formed as individuals and communities negotiated the competing forces of integration and differentiation. This study demonstrates the value of approaching identity from multiple scales. If identity is understood as fundamentally multi-faceted and multi-scalar, even seemingly homogeneous cultural units are characterized by social diversity and the tension that accompanies such diversity. The patterns of production visible in utilitarian corrugated pottery provide a nuanced method of clarifying the complex identities of Ancestral Puebloan communities and assessing social connections and differences between groups.

Informal settlements are more than just a collection of corrugated iron units. They are not a building type but an urban phenomenon that is prevalent in South Africa due to reasons such as housing backlog (Huchzermeyer, 2010:132) and the need for livelihood (Huchzermeyer, 2011:33). It offers choice, it gives people what they want and it is affordable (Mills, 2012:1). “Informalization is a process where the poor evade rules to produce outcomes that they need, but that are otherwise too controlled for them to reach” (Cross, 2005:3). Urbanisation in South Africa is increasing every day (Mills, 2012:1) and the poor in shacks continue to deliver housing to themselves using informal mechanisms (Cross, 2005:2). There is a need to recognise and appreciate the economic, social and environmental benefits that informal settlements can bring to the urbanisation process (Mills 2012, pp1). Informal housing exists due to the gap in the market where the poor are unable to afford the available kind of housing (Cross, 2005:3). One must understand that formalising the informal does not always have to be through eradication of existing slums according to MDG seven Target 11 (Huchzermeyer, 2011:16) and it can also take place as an in situ upgrading (Huchzermeyer, 2011:30). It can sometimes be an “invisible” form of development of the community which leads to a self-sustaining future upgrade such as project that Nabeel Hamdi pioneered namely ‘the Buffalo Project’ (Hamdi, 2010:106). Sometimes the existing abandoned structures such as a community hall can be reactivated, resulting in an improvement of an area in terms of addressing the needs of the community for a market space (Hamdi, 2010:109) or changing the appearance of an informal settlement resulting in a change in people’s perceptions of the area (Feireiss, 2011:114). In this way the “small change” can grow over time and result in the development of an entire settlement by its own residents. This dissertation explores the importance of the architectural facilitator as the “missing” profession amongst other professionals who are involved with upgrading projects such as architects, engineers, NGOs, government entities, private stakeholders and many more (Hamdi, 2010:96). The architectural facilitator will be able to accommodate the gaps that have been challenging the Upgrade of the informal settlements in South Africa by creating an understanding between the issues that exist in an informal settlement, prioritising the needs and selecting interventions that address the most pressing needs in an informal settlement. The aim is to create a universal understanding of how one can approach the issue of upgrading informal settlements in order to derive a strategic framework that will lead to a long-term sustainable development. A revised toolkit is introduced to guide the decision-makers such as the Architects, government entities or anyone with an understanding of Architecture, to be able to organise their findings in a prioritised manner and implement interventions according to what the priority needs in the context are. The important thing to highlight in this paper is the theoretical importance of livelihoods to the understanding of poverty in the urban context and the implication of these theories in practice (Hamdi, 2010:185). Therefore, designing an upgrade plan and intervention which will be a long-term project, accepted by the community and accommodating the community’s need for livelihood. Topics such as ownership through tenure security and identifying existing nodes of energy are the main focus of this thesis document. / Dissertation (MSc (Applied Science) )--University of Pretoria, 2012. / Architecture / unrestricted

It is well known that transportation means high and varying loads for products as well as packages. To develop corrugated boxes with optimal design and efficient use of raw materials is crucial. Vibrations and shocks acting on pallets during transportation are transferred to the corrugated boxes and considerably reduce the integrity and life time of the boxes. The development of experimental and analytical tools for measurement and prediction of the influence of dynamic loads on the box performance, such as stacking strength and conservation of stacking pattern would therefore be of large practical importance. In order to develop such tools, it is important to know the load distribution between different boxes. This master thesis presents a technique for investigating these stresses based on a pressure sensitive film, which gives many data points. A series of tests using random and sinusoidal vibration testing have been done utilising this technique and results are presented for different positions on the pallet and for different box filling methods. Investigations performed on the vibrations of the boxes also demonstrate a pitch type of motion. A level-crossing study on the forces existing between the boxes shows a Rayleigh force distribution. A mathematical model is also proposed for simulation of a stacking system. Advantages and disadvantages with this technique and with the model are described. Comparison between the experimental and numerical results shows a proper correlation. Using the pressure sensitive film as a quantitative sensor and applying the recorded data for the statistical study of the contact forces existing in a stack of boxes gives useful and important results for further analysis of the fatigue life and vulnerable positions of boxes.

[pt] A aplicação de um guia circular corrugado como alimentador é analisada a partir do conhecimento das distribuições de campo elétrico e magnético no plano focal de refletores parabólicos. O desenvolvimento matemático dos campos no interior da estrutura conduz a expressões para os diagramas de radiação e demais parâmetros de interesse. Diversas peculiaridades inerentes à propagação em estruturas corrugadas ficam caracterizadas ao longo da análise, alcançando-se a notável situação de simetria dos diagramas e polarização cruzada nula. Inclui-se um projeto para utilização de refletores de pequena e grande distância focal. / [en] The use of a corrugated circular waveguide as a feeder is analysed by considering the distributions of eletric and magnetic fields at the focal plane of parabolic reflectors. The mathematical field development inside the structure leads to expressions of radiation patterns and the necessary parameters. Several peculiarities in connection with the propagation in corrugated structures are characterized through the analysis, obtaining the remarkable situation of patterns simmetry and zero cross- polarization. A feeder design for using small and large focal lenght reflectorsis included.