1,012 research outputs found
Drag and inertia coefficients for horizontally submerged rectangular cylinders in waves and currents
No full textThe results of an experimental investigation carried out to measure combined wave and current loads on horizontally submerged square and rectangular cylinders are reported in this paper. The wave and current induced forces on a section of the cylinders with breadth-depth (aspect) ratios equal to 1, 0.5, and 0.75 are measured in a wave tank. The maximum value of Keulegan-Carpenter (KC) number obtained in waves alone is about 5 and Reynolds (Re) number ranged from 6.3976103 to 1.186105. The drag (CD) and inertia (CM) coefficients for each cylinder are evaluated using measured sectional wave forces and particle kinematics calculated from linear wave theory. The values of CD and CM obtained for waves alone have already been reported (Venugopal, V., Varyani, K. S., and Barltrop, N. D. P. Wave force coefficients for horizontally submerged rectangular cylinders. Ocean Engineering, 2006, 33, 11-12, 1669-1704) and the coefficients derived in combined waves and currents are presented here. The results indicate that both drag and inertia coefficients are strongly affected by the presenceof the current and show different trends for different cylinders. The values of the vertical component inertia coefficients (CMY) in waves and currents are generally smaller than the inertia coefficients obtained in waves alone, irrespective of the current's magnitude and direction. The results also illustrate the effect of a cylinder's aspect ratio on force coefficients. This study will be useful in the design of offshore structures whose columns and caissons are rectangular sections
University Teaching Reconsidered: Justice, practice,inquiry
No full texthttp://librarysearch.auckland.ac.nz/primo_library/libweb/action/display.do?fn=search&doc=uoa_voyager1964311&vid=UOA2_
Dynamix on the Frame VM: Declarative dynamic semantics on a VM using scopes as frames
No full textOver the years virtual machines (VMs) have been created to abstract over computer hardware. This simplified code generation and allowed for easy portability between hardware platforms. These VMs are however highly tailored to a particular runtime model. This improves the execution speed, but places restrictions on the types of languages that the VM supports. In this thesis the Frame VM was developed as a VM that supports many different types of languages in a principled way. Achieving this is done by basing the VM on language independent models of memory and control flow. Usage of the scopes-as-frames paradigm and control frames resulted in an instruction set that is relatively small at its core, but does allow for the construction of complex control flow. As an effect, many different programming languages can be compiled to the Frame VM. In addition to this VM, a Domain Specific Language (DSL) for executable semantics of programming languages was created. This language, Dynamix, allows for a modular approach to writing the semantics of a language. Additionally, Dynamix provides a meta-compiler that uses these semantics of a language to compile programs to the Frame VM. To validate the Frame VM, direct compilers for Rust and Prolog have been created in a student project and compilers for Scheme and Tiger were created using Dynamix. Using these semantics of Scheme and Tiger, it was possible to execute programs containing usage of call/cc and a suite of Tiger benchmark programs. Furthermore, the control flow of Tiger was extended with exceptions and generator functions. This extension did not require any changes to the existing semantics, showing the modularity of control achieved when using Dynamix and the Frame VM.Computer Scienc
Worlds and words: education for social justice in a postgraduate course
No full textBook chapter reviewed and accepted by editors, book to be published in late 2009http://librarysearch.auckland.ac.nz/primo_library/libweb/action/display.do?fn=search&doc=uoa_voyager1964311&vid=UOA2_
Introduction
No full textAs a dynamic activity that has significant and far-reaching consequences, university teaching is constantly under review. Ideas about good teaching, its objectives, and the means of achieving those objectives are shifting and contested.http://librarysearch.auckland.ac.nz/primo_library/libweb/action/display.do?fn=search&doc=uoa_voyager1964311&vid=UOA2_
MIME Configurations for Using VM on Emacs
No full textP(論文)Emacsは単なる文書編集アプリケーションではなく、様々な機能をマクロとして附加することができる。本稿では、このEmacsでメールを読み書きするための追加マクロとしてVMを取り上げる。VMでは電子メール本文におけるMIME対応はなされているが、ヘッダにおけるMIME対応はなされていない。本稿では、VMからSEMIを利用し、電子メールヘッダに日本語を利用するためのMIME設定について述べる。当初の目的であるEmacsとVMによる電子メールヘッダにおける日本語のMIME処理は実現できた。ただし、Emacsの版によってはうまく実現できないという情報もある。汎用的な方法を確立するためには、更なる調査が必要である。Emacs is an application software that can be used not only for editing plain texts but also for many other purposes by adding facilities as macros. In this study, VM was used as auxiliary macro for reading and writing e-mails by Emacs. VM has MIME reading and writing ability in the body part of e-mail messages but not in the header part. In this paper, MIME configurations for using SEMI from VM for processingJapanese characters in e-mail headers are described. The goal of this study, i.e., reading and writing MIME messages in header parts, was achieved. However, the author has information that the method described in this paper does not work well with one version of Emacs (Emacs 22). Establishment of a general method is a subject of future work.departmental bulletin pape
Hydrodynamics of an oscillating articulated eel-like structure
No full textThis study examines the hydrodynamic performance of a highly simplified eel-like structure consisting of three articulated segments with the two aft segments oscillating. A physical model was built and tested to determine the forces developed with the model stationary, to find the self-propulsion speed, and to explore the effect on hydrodynamic performance of different swimming patterns. It was found that hydrodynamic performance increases with increasing oscillation frequency; the highest forces when stationary, and the highest self-propulsion speeds were produced by swimming patterns in which the amplitude in the aft segment is larger than that in the forward segment, and in which the motion of the aft segment lags the forward segment. A simple semi-empirical model based on Morison’s equation was implemented to predict the hydrodynamic forces. This was shown to predict mean thrust well in cases in which the aft segment oscillates in phase with the forward segment, but less reliably when the phase difference between the segments increases. Force time histories are generally not well-predicted using this approach. Nonetheless, self-propulsion speeds are predicted within 30% in all cases examined
Introduction
No full texthttp://librarysearch.auckland.ac.nz/primo_library/libweb/action/display.do?fn=search&doc=uoa_voyager1774980&vid=UOA2_
Flow compensation in a MEMS dual-thermal conductivity detector for hydrogen sensing in natural gas
No full textConventional thermal conductivity detectors (TCDs) demonstrate a flow dependence. The approach presented here to reduce the flow dependence is based on the on-line flow compensation using two thin-film sensors on membranes in parallel on the same chip that are differentially operated. These are laterally identically, but with a different depth of the detection chamber, resulting in different quasi-static sensitivities to the thermal conductivity of the sample gas. The effects of conduction and convection in the structure have been studied using COMSOL Multiphysics. First prototypes have been fabricated and are presently tested.Accepted Author ManuscriptElectronic Instrumentatio
Who creates the narrative? The case of RE/F/r:ACE, a participatory media artwork in city space
No full textThis paper discusses the roles of artist, author, participant and spectator within the context of participatory media art events, with reference to RE/F/r.ACE, a participatory video project developed by Andy Best-Dunkley, Merja Puustinen and Victor Khachtchanski. RE/F/r.ACE enables participants to easily contribute their own images as raw material to the ongoing flow of visual and audio narrative projected into the public city environment. Situating the project within an art historical context, the paper discusses the social and political coding of the architectonic urban environment, and the rules and norms relating to, and controlling, our everyday use of public space. When the notion of free “open to all” public space is under threat from ongoing commercialisation and gentrification of urban centres worldwide, RE/F/r.ACE is an example of one attempt to draw attention to this transformation in a creative, positive, and artistic manner.Peer reviewe
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