The hydrodynamics of water-walking insects and spiders

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2006.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (leaves 142-152).We present a combined experimental and theoretical investigation of the numerous hydrodynamic propulsion mechanisms employed by water-walking arthropods (insects and spiders). In our experimental study, high speed cinematography and flow visualization techniques are used to determine the form of the flows generated by water-walkers. In our supporting theoretical study we provide a formal fluid mechanical description of their locomotion. We focus on the most common means of walking on water such as the alternating tripod gait, rowing, galloping and leaping. We also examine quasi-static modes of propulsion in which the insect's legs are kept stationary: specifically, Marangoni propulsion and meniscus-climbing. Special attention is given to rationalizing the propulsion mechanisms of water-walking insects through consideration of the transfer of forces, momentum and energy between the creature and its environment.by David Lite Hu.Ph.D

Optimal transport strategies

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 103-112).It is generally presupposed that the shapes and mechanisms encountered in nature have evolved in such a way as to maximize the robustness of a species. However, most such optimization problems arising in biology are sufficiently complex that it is neither clear what is being optimized, nor what are the relevant constraints. We here consider a number of natural fluid transport systems that may be framed in terms of constrained optimization problems. We first examine natural drinking strategies. We classify the drinking strategies of a broad range of creatures according to the principal forces involved, and present physical pictures for each style. Simple scaling arguments are developed and tested against existing data. While suction is the most common drinking strategy, various alternative styles have evolved among creatures whose morphological, physiological and environmental constraints preclude it. Many small creatures rely on relatively subtle capillary effects for fluid uptake. Particular attention is given to nectar drinking strategies. Nectar drinkers must feed quickly and efficiently due to the threat of predation. While the sweetest nectar offers the greatest energetic rewards, the sharp increase of viscosity with sugar concentration makes it the most difficult to transport. An optimal sugar concentration is thus expected for which the energy intake rate is maximized. An extensive data set indicates that the sugar concentration that optimizes energy transport depends exclusively on the drinking technique employed. We identify three nectar drinking techniques: active suction, capillary suction, and viscous dipping and rationalize the reported optimal concentrations for each through consideration of the appropriate constrained optimization problem. Blood flow in vertebrates and phloem flow in plants are known to be optimized for efficient transport of oxygen and sugar, respectively. Efficient transport of material is similarly advantageous in engineered transport systems such as traffic and wireless networks. We thus develop a general framework for determining the concentration that maximizes the material flow in a number of transport systems.by Wonjung Kim.Ph.D

Oceanus.

v. 26, no. 1 (1983

Engineering derivatives from biological systems for advanced aerospace applications

The present study consisted of a literature survey, a survey of researchers, and a workshop on bionics. These tasks produced an extensive annotated bibliography of bionics research (282 citations), a directory of bionics researchers, and a workshop report on specific bionics research topics applicable to space technology. These deliverables are included as Appendix A, Appendix B, and Section 5.0, respectively. To provide organization to this highly interdisciplinary field and to serve as a guide for interested researchers, we have also prepared a taxonomy or classification of the various subelements of natural engineering systems. Finally, we have synthesized the results of the various components of this study into a discussion of the most promising opportunities for accelerated research, seeking solutions which apply engineering principles from natural systems to advanced aerospace problems. A discussion of opportunities within the areas of materials, structures, sensors, information processing, robotics, autonomous systems, life support systems, and aeronautics is given. Following the conclusions are six discipline summaries that highlight the potential benefits of research in these areas for NASA's space technology programs

M.A.P.S. Digest, vol.26 no.3 (March 2003)

https://ir.uiowa.edu/midamericapaleo/1212/thumbnail.jp

Oceanus.

v. 35, no. 3 (1992

Redefining the anthropomorphic animal in animation

The use of anthropomorphic animal characters is pervasive in animation, but there has been little examination of how and why these are created, and how a viewing audience understands them. This Practice-based PhD examines how a re-defining of anthropomorphic and zoomorphic representation might bring a new impetus to the use of animal imagery within contemporary animation practice. An initial stage of research was to define the term anthropomorphism both as a visual language within animation practice and in the wider contexts of scientific and philosophical discourse. Social and psychological aspects are discussed, recognising this form of hybrid representation throughout the development of human culture. Links with Human Animal Studies disciplines raised the question of relating anthropomorphism to negative aspects of anthropocentrism and this led to a second stage of the research that explores ways of working with anthropomorphism that do not promote an anthropocentric bias. This is firstly achieved through the devising of a new theoretical approach to character analysis that is based on the recognition of perceptual aesthetic and sensual animal qualities in human-led , animal-led and design-led anthropomorphic characters, rather than a reliance on conceptual symbolic referencing of human experiences, goals, and narratives. Moving into the practice and influence from historical animation work provides impetus for a move away from character and narrative based work. Experimental animation techniques are used to create rhythms and patterns of abstracted animal and human imagery. This new work is based on contemporary ecological ideas that discuss relationships between humans and animals as interconnected species, thus providing a second way of lessening of anthropocentric bias in the subject matter. Having a starting point of aesthetic and sensual responses to actual experiences with animals is an important factor and live action film is re-animated to create digitally manipulated rhythms of colour, texture, movement and sound. The practical research outcomes are animation samples that evidence the coming together of experimental digital techniques and contemporary ecological subject matter. An action research model was devised for the research to enable the integration of theory and practice, and reflection on theory and practice to have an important influence on the practical outcomes. The approach taken was dependent on experience as a creative practitioner and as a teacher helping others to develop a sustainable creative practice, in allowing an open and intuitive discovery of ideas from both theoretical and practical explorations to create a flow through the research. The combination of theoretical and practical research undertaken provides an impetus towards the creation of future animation work using an anthropomorphic visual language redefined as zooanthropomorphic animation . The submission includes outcomes of a written thesis and links to practical animation work

Oceanus.

v. 24, no. 4 (1981

Non-determinism in the narrative structure of video games

PhD ThesisAt the present time, computer games represent a finite interactive system. Even in their more experimental forms, the number of possible interactions between player and NPCs (non-player characters) and among NPCs and the game world has a finite number and is led by a deterministic system in which events can therefore be predicted. This implies that the story itself, seen as the series of events that will unfold during gameplay, is a closed system that can be predicted a priori. This study looks beyond this limitation, and identifies the elements needed for the emergence of a non-finite, emergent narrative structure. Two major contributions are offered through this research. The first contribution comes in the form of a clear categorization of the narrative structures embracing all video game production since the inception of the medium. In order to look for ways to generate a non-deterministic narrative in games, it is necessary to first gain a clear understanding of the current narrative structures implemented and how their impact on users’ experiencing of the story. While many studies have observed the storytelling aspect, no attempt has been made to systematically distinguish among the different ways designers decide how stories are told in games. The second contribution is guided by the following research question: Is it possible to incorporate non-determinism into the narrative structure of computer games? The hypothesis offered is that non-determinism can be incorporated by means of nonlinear dynamical systems in general and Cellular Automata in particular