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Imperial Europes relationship with the tropical world was characterized by intrigue and fascination combined with a fear of difference. This combined intrigue and fear developed over time into a set of stereotypes and myths about the tropics, which by the 19th century had solidified into a powerful discourse historian David Arnold calls tropicality. As Europes interaction with the tropical world increased and its need for tropical resources grew, tropicality became a powerful tool for legitimizing European interference in and exploitation of the tropics. Embedded in the language of science and the promise of progress, it reaffirmed European superiority and its necessary role as the bearer of civilization for the tropical world. <p>Perhaps the most powerful characteristic of tropicality was its inherent ambivalence. The Amazon basin has been a particularly important source for the creation and maintenance of these stereotypes about the tropical world. Reinvented by Alexander von Humboldt as an exotic paradise at the beginning of the nineteenth century, the Amazon basin continued throughout the century to inspire commentary, exploration, and exploitation from abroad. As contact with the Amazon increased, ideas about the tropics began to change. What once was thought of as a pristine paradise became perceived as sinister, diseased, and savage. By the end of the nineteenth century, the tropical world, its people and nature, was considered to be an obstacle to civilization, and its very ability to become civilized began to be questioned.<p>Rubber, an increasingly important and lucrative imperial resource at the end of the nineteenth century, brought people from around the world to the Amazon basin. This resulted in the creation of a contact zone of different peoples, cultures, and idea, which was important for the moulding and maintenance of tropical stereotypes and myths. This was especially the case in the Putumayo, a border zone between modern day Colombia and Peru, where the brutal treatment of workers and the promise of civilization clashed. Through an exploration of travel diaries, newspapers, parliamentary papers, and other works about the tropics and rubber, this thesis argues that the manner in which rubber and its environment were depicted legitimized its control and exploitation from the outside. Couched in the rhetoric of civilization, tropicality helped justify the exploitation of rubber, the environment in which it grew, and the peoples that lived there.

This experiment produces a new flexible heat pipe, and further tests and explores its characteristics and performance. The heat pipe is made of silicone rubber, a kind of polymer material, and was molded by hot embossing. Characteristics of this material include good bending resistance, lightness, and good resistance to high temperature. Furthermore, copper sheets connected with silicone were placed at the evaporator section and condenser section to enhance heat transfer effects. DI water in the pipe was used as the working medium, and two-layer 250 mesh copper nets were used as a wick to strengthen the heat pipe¡¦s capillary effects. The researcher set the vacuum degree at 0.0658 atm to test the pipe¡¦s performances at different powers. Key findings include an optimum filling ratio of 40%, and a largest heat flux of 11.75 W/cm2 during the proficiency test. In addition to the proficiency test . The influence of different angles of bends (0 ~ -90¢X) on the pipe¡¦s heat transfer performance was also tested and based on heat thermal resistance obtained, found that the best bended angle of the flexible heat pipe was -15¢X, and thermal resistance will increase with the angle(-30 ~ -90¢X). The experiment proves a small angle bend that is helpful for the working medium to flow back to the evaporator section, but the heat transfer performance would shrink because the wick could not affix to the inner wall of the pipe if the angle is too large. This work shows the proper combination of pipe parameters will significantly improve heat transfer performance.

<p>Magnetorheological (MR) rubber materials are the solid analogue of magnetorheological fluids; i.e. their rheological properties can be controlled continously, rapidly, and reversibly by an applied magnetic field. They consist of magnetically polarisable particles in an elastomer matrix and they can be made to respond to changes in their environment; hence, they are considered as "smart" materials. Examples of potential applications for these materials are adaptive tuned vibration absorbers, stiffness-tuneable mounts and suspensions, and automotive bushings.</p><p>The purpose of this work was to increase the knowledge relating to magnetorheological materials for damping applications. The materials should exhibit a large response to an applied magnetic field, and have good mechanical and long-term properties.</p><p>MR rubber materials were made from nitrile, natural and silicone rubber, with irregularly shaped iron particles several micrometres in size. The particles were not aligned by a magnetic field prior to the vulcanisation; hence, the materials can be considered to be isotropic. These materials show a large MR effect, i.e. an increase in the shear modulus when a magnetic field is applied, although the particles are not aligned within the material. This is explained by the low critical particle volume concentration (CPVC) of such particles. Similar behaviour can be obtained with materials containing carbonyl iron, if the particles are aggregated so that they behave like large irregular particles. The iron particle concentration must be very close to the CPVC in order to obtain a large MR effect without alignment of the particles.</p><p>The absolute MR effect (MPa) in an isotropic MR rubber material with large irregular iron particles is independent of the matrix material, and the relative MR effect (%) can thus be increased by the addition of plasticisers. However, the obtainable effect is limited by the reinforcement of the particles and by friction between the particles. Therefore, it is very difficult, if not impossible, to achieve an MR effect larger than 60%.</p><p>Other ways of increasing the MR effect are to increase the strength of the magnetic field, although the materials saturate magnetically at high field strengths, or to use small strain amplitudes. The strong strain amplitude dependence of the MR effect suggests that MR rubber materials are most suitable for low amplitude applications, such as sound and vibration insulation. Measurements at frequencies within the audible frequency range show that this is a promising application for MR rubber materials.</p><p>The incorporation of large amounts of iron into the rubber matrix decreases the oxidative stability dramatically. This is probably due to iron oxides on the surface of the particles, and to the fact that the oxidation rate is enhanced by iron ions, which are able to diffuse into the matrix. Standard antioxidants do not provide sufficient stabilisation for MR rubbers. Thus, proper stabilisation systems have to be found in order for these materials to be successful in applications.</p>

Thesis--St. Catharine's College, Cambridge. / Typescript (carbon) with ms. corrections. Without thesis statement. Appendices 1-3 by N. Sheppard and G.B.B.M. Sutherland. Bibliography: leaves 209-216.

Project Completion Report OWRT Project No. A-075-ARIZ / Agreement No. 14-34-0001-7006 / Project Dates: July 1976 - June 1977 / "The work upon which this report is based was supported by funds provided by the United States Department of the Interior, Office of Water Research and Technology as authorized under the Water Resources Research Act of 1964, the State of Arizona, and the Arizona Department of Transportation and Federal Highway Administration

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Submitted to The Arizona Highway Department Phoenix, Arizona for Research Project - Arizona HPR-1-14(167) / The research has been directed toward obtaining information on some of the physical properties of various asphalt- rubber (A-R) mixes as related to waterproof membrane applications. In particular, three rubber particle size distributions and three asphalt-rubber spread quantities were investigated. Laboratory testing utilized for physical property determination included thin film permeability, water absorption (ASTM D570-72), Water Vapor Transmission (ASTM E96-72, procedure BW), ductility (ASTM D113-74), Tensile-Toughness, viscosity and slope stability. The results of the study showed that the A-R as an integral membrane is relatively impermeable. The addition of the rubber does not affect the permeability of an otherwise homogeneous asphalt film. Physical property values of asphalt that are increased when rubber is added include water absorption, slope stability, toughness and viscosity. Those that exhibit lower physical property values include ductility and slope/flow characteristics. Installation of experimental field plots provided additional positive information on the waterproofing characteristics of the A-R and also helped develop field procedures on A-R application to a prepared subgrade.

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