The development of a design tool for 5-speaker surround sound decoders

This thesis presents the development of a software-based decoder design tool (DDT) for producing Ambisonic decoders optimised for playback over 5-speaker layouts. The research specifically focuses on developing decoders for irregular layouts with loudspeakers at a constant radial distance from the central listening position. It was motivated by the desire to provide better surround sound over the standard ITU 5-speaker layout for listeners in the sweet spot and off-centre positions. A wide-ranging literature review is presented revealing the need for such work. The DDT employs the Tabu Search algorithm to seek improved decoder parameters according to a multi-objective fitness function. The fitness function encapsulates criteria from psychoacoustic models as a set of objectives. In order to ensure the objectives were treated equally a method known as „range-removal‟ was used for the first time in Ambisonic decoder design. A companion technique termed „importance‟ allows the systematic prioritisation of range-removed objectives giving a designer control over desired decoder criteria. Additional elements exist in the DDT that can be turned on or off in different combinations. They include: a novel component for producing decoders with even performance by angle, a novel component for producing performance that correlates with the pattern of human spatial resolution estimated in previous Minimum Audible Angle experiments, and the ability to produce frequency dependent or independent decoders of different orders. Moreover, the user of the DDT can optimise performance for a single listener or multiple distributed listeners. To make the DDT as interactive as possible searches can optionally run on a High Performance Computer. This thesis also details the extensive testing of Ambisonic decoders for the ITU layout. Decoders have been assessed subjectively in listening tests and objectively using binaural measurements which has verified the methods developed in this research and the DDT‟s concept. Furthermore, decoders derived by the DDT have been compared to existing decoders and the results show they give equal or better performance. The development of a fully-functioning DDT which incorporates techniques for range-removal, importance, even performance by angle, minimum audible angle, off-centre listeners and their use in any combination represent the key outcomes of this work.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Analysis of noise spectra in GaAs and GaN Schottky barrier diodes

The Monte Carlo method is applied in this paper to characterize the noise spectra of GaAs and GaN Schottky barrier diodes operating under static and time varying conditions. We show the influence of the structure of the diode and working regimes on the noise spectrum of the diodes. Besides, the paper evaluates the capabilities of published analytical models to describe the noise spectra in Schottky diodes under time varying conditions. This is a further step towards the development of a design tool that integrates both the electrical response and the intrinsic noise generated in the devices.ROOTHz (FP7-243845

Simulation and experimental investigation of pool boiling on a silicon wafer with artificial nucleation sites

This paper reports progress on a project to develop a design tool for large arrays of nucleation sites at specified locations to achieve high rates of cooling by pool boiling. The tool will be based on an improved version of a hybrid simulation, in which the 3-D temperature field in the wall is solved numerically, along with simple sub-models for bubble-driven heat transfer that require experimental calibration. Improvements to the computer code and progress with the experiments are reported briefly. The paper focuses on the development of a sub-model for the lateral coalescence of bubbles, which is shown to cause irregularity in the bubble production by a regular array of nucleation sites

CubeSat Active Thermal Management in Support of Cooled Electro-Optical Instrumentation for Advanced Atmospheric Observing Missions

The need for advanced cooled electro-optical instrumentation in remote observations of the atmosphere is well known and demonstrated by SABER on the TIMED mission. The relatively new use of small satellites in remote earth observing missions as, well as the challenges, are epitomized by the upcoming NOAA EON-IR 12U CubeSat missions. These advanced CubeSat missions, which hope to accomplish scientific objectives on the same scale as larger more traditional satellites, require advanced miniaturized cryocoolers and active methods for thermal management and power control. The active CryoCubeSat project (ACCS) is a demonstration of such a technology. Utilizing Ultrasonic Additive Manufacturing (UAM) techniques, a Mechanical Pumped Fluid Loop (MPFL), and miniature pumps and cryocoolers to create a closed loop fluid-based heat interchange system. The ACCS project creates a two-stage thermal control system targeting 6U CubeSat platforms. The first stage is composed of a miniature Ricor K508N cryocooler while the second is formed by a UAM fabricated heat exchanger MPFL system powered by a micro TCS M510 pump. The working fluid is exchanged between a built-in chassis heat exchanger and a deployable tracking radiator. This work details the theory design and testing of a relevant ground-based prototype and the analysis and modeling of the results as well as the development of a design tool to help in customized active thermal control designs for small satellites. Ultimately, the ACCS project hopes to enable a new generation of advanced CubeSat atmospheric observing missions

Developing a Conceptual Design Engineering Toolbox and its Tools

In order to develop a successful product, a design engineer needs to pay attention to all relevant aspects of that product. Many tools are available, software, books, websites, and commercial services. To unlock these potentially useful sources of knowledge, we are developing C-DET, a toolbox for conceptual design engineering. The idea of C-DET is that designers are supported by a system that provides them with a knowledge portal on one hand, and a system to store their current work on the other. The knowledge portal is to help the designer to find the most appropriate sites, experts, tools etc. at a short notice. Such a toolbox offers opportunities to incorporate extra functionalities to support the design engineering work. One of these functionalities could be to help the designer to reach a balanced comprehension in his work. Furthermore C-DET enables researchers in the area of design engineering and design engineers themselves to find each other or their work earlier and more easily. Newly developed design tools that can be used by design engineers but have not yet been developed up to a commercial level could be linked to by C-DET. In this way these tools can be evaluated in an early stage by design engineers who would like to use them. This paper describes the first prototypes of C-DET, an example of the development of a design tool that enables designers to forecast the use process and an example of the future functionalities of C-DET such as balanced comprehension

Sustainable development of biogas resources in East Africa using transdisciplinary design models

Installation of anaerobic digestion systems in urban developing communities has the potential to address multiple problems related to energy and sanitation in a combined systems approach. Anaerobic digesters are used to generate a relatively clean and rich source of energy in the form of biogas to address energy poverty issues. The design resources available for anaerobic digestion projects must be improved to provide greater technical support and project transparency. In order to develop holistic solutions to grand challenges like energy poverty, engineers must be prepared to operate with the complexities of diverse environments. Globalization and the improvement of transdisciplinary project design models have had a profound influence on the international development community. Development engineers must address problems from various frames of reference so as to generate solutions which will be effective and long lasting. The methods of fully integrating systems into a community, while maintaining high quality engineered solutions, are paramount. Implementation of appropriate technologies will be a key enabling technique for effective problem solving and the application of solutions. The purpose of this research is to examine the biogas mechanisms, infrastructure, design tools, and design models that can be developed and implemented to ensure quality, systems based solutions delivered in an effectively holistic and transdisciplinary manner. In order to understand this, the literature exploring the various processes and technologies powering biogas programs as well as those pertaining to transdisciplinary sustainable development models are analyzed. Additionally, this research expands on the development of a design tool and construction manual for biogas digester programs and comments on the current design and implementation models in biogas programs in the context of working with the United Nations on urban biogas resources

Finite element simulations of laminated composite forming processes

Continuous Fibre Reinforced Polymers (CFRPs) combine strength and stiffness of fibres with the design flexibility of polymeric matrix materials.\ud Fast production methods like thermo-folding, diaphragm forming or stamping can produce large numbers of CFRP components in a cost efficient way.\ud Pre-consolidated laminates are heated above their melting temperature and subsequently re-shaped. These forming processes can introduce unacceptable shape distortions such as springback, wrinkling or tearing.\ud The objective of this research is the development of a design tool for high precision CFRP components made from multi-layer laminates. Optimisation of the CFRP design and the forming process reduces costly trial-and-error\ud procedures and can significantly shorten the time-to-market. This requires a predictive model that is robust, accurate and fast. Such an all-encompassing procedure is not readily available

Design Criteria for Zero Leakage Connectors for Launch Vehicles. Mathematical Model of Interface Sealing Phenomenon, Volume 2 Final Report

Mathematical model of interface sealing phenomenon in determining design criteria for zero leakage connectors for launch vehicle

[Report of] Specialist Committee V.4: ocean, wind and wave energy utilization

The committee's mandate was :Concern for structural design of ocean energy utilization devices, such as offshore wind turbines, support structures and fixed or floating wave and tidal energy converters. Attention shall be given to the interaction between the load and the structural response and shall include due consideration of the stochastic nature of the waves, current and wind