Misery Island

Thesis (M.M.)--Boston UniversityMisery Island is a monologue for high soprano and string quartet. The libretto, written by Nerissa Cooney, includes original verse as well as fragments from Henry David Thoreau's Walden Collaboration during the production of the libretto offered an opportunity to pian the emphasis and phrasing of the text; in particular, via our voices, we could each express our own "reading" of the text to each other This process often revealed dynamics and stresses embedded in the text. Being able to volley ideas and rewrite the text established many themes that would be explored as music later on. I refer to the five movements in the piece as a monologue because it is intended as a single dramatic statement. The libretto offered a bounty of opportunities to compose music with the intention of adding a particular perspective to a given text. I specifically tried to keep the performance in mind while composing, attempting to support the vocalist dramatically with the quartet material, in general, I tried to make a piece in which the text and the music are mutually supportive. In a sense, a major goal of mine was to let the text drive the music to places it would otherwise not have gone. The challenge of experimenting with new ideas in composition while striving to best represent a desired dramatic effect or scenario has proved itself to be a fruitful way of finding fresh material with purpose and character Misery Island was premiered at the Boston University Concert Hall on April 8, 2013, with Katrina Galka singing, Nelli Jabotinsky and Hyunji Kim on violin, Evan Perry on viola, Robert Mayes on violoncello, and the composer conducting

Sensitivity of Pagurus bernhardus (L.) to substrate-borne vibration and anthropogenic noise

© 2015 Elsevier B.V. Despite the prevalence of vibration produced by anthropogenic activities impacting the seabed there are few data and little information as to whether these are detected by crustaceans and whether they interfere with their behaviour. Here the sensitivity of unconditioned Pagurus bernhardus to substrate-borne vibration was quantified by exposure to sinusoidal vibrations of 5-410Hz of varied amplitudes using the staircase method of threshold determination, with threshold representing the detection of the response and two behavioural responses used as reception indicators: movement of the second antenna and onset or cessation of locomotion. Thresholds were compared to measured vibrations close to anthropogenic operations and to the time in captivity prior to tests. Behaviour varied according to the strength of the stimulus with a significant difference in average threshold values between the two behavioural indicators, although there was an overlap between the two, with overall sensitivity ranging from 0.09-0.44ms -2 (root mean squared, RMS). Crabs of shortest duration in captivity prior to tests had significantly greater sensitivity to vibration, down to 0.02ms -2 (RMS). The sensitivity of P. bernhardus fell well within the range of vibrations measured near anthropogenic operations. The data indicate that anthropogenic substrate-borne vibrations have a clear effect on the behaviour of a common marine crustacean. The study emphasises that these vibrations are an important component of noise pollution that requires further attention to understand the long term effects on marine crustaceans

Kinetic energy choice in Hamiltonian/hybrid Monte Carlo

We consider how different choices of kinetic energy in Hamiltonian Monte Carlo affect algorithm performance. To this end, we introduce two quantities which can be easily evaluated, the composite gradient and the implicit noise. Results are established on integrator stability and geometric convergence, and we show that choices of kinetic energy that result in heavy-tailed momentum distributions can exhibit an undesirable negligible moves property, which we define. A general efficiency-robustness trade off is outlined, and implementations which rely on approximate gradients are also discussed. Two numerical studies illustrate our theoretical findings, showing that the standard choice which results in a Gaussian momentum distribution is not always optimal in terms of either robustness or efficiency.Comment: 15 pages (+7 page supplement, included here as an appendix), 2 figures (+1 in supplement

An investigation of the feasibility of a spacecraft multifunctional structure using commercial electrochemical cells

Multifunctional structures offer the potential for large savings in the mass and cost of spacecraft missions. By combining the functions of one or more subsystems with the primary structure, mass is reduced and internal volume freed up for additional payload, or removed to reduce structural mass. Lithium batteries, increasingly preferred to other power storage solutions, can be employed to produce such structures by incorporating prismatic batteries into structural sandwich panels. Such “powerstructures” can reduce the mass and volume of the power storage subsystem.After reviewing the current work in the field of multifunctional structures, this thesis describes the objective of the research, to examine the usefulness and feasibility of a multifunctional structure based on commercial lithium cells and sandwich structures. The next section presents a study that quantifies the benefits of this technology, showing maximum savings of up to 2% of total mass, and 0.5-1% for common spacecraft designs.The next section describes experimental investigations into the mechanical suitability of commercial PLI cells for use in the multifunctional structure. Firstly, the effect of launch vibration was considered: 15 and 25 grms tests showed no measurable loss in electrical performance. Then, the structural attributes of the cells were measured using a dynamic shear test. The shear modulus of the cells was found to be rather lower than that of an aluminium honeycomb core material.Consideration is then given to the practical implications of a multifunctional structure. The feasibility of manufacturing is assessed through the construction of a trial panel, showing that the cells lose some capacity and suffer an increase in internal resistance in a high-temperature adhesive cure and that a cold-bonding process may thus be preferable. The resultant panel was then vibrated on an electrodynamic shaker to both assess the resilience of the cells and test the reliability of finite element models. These finite element models are then used for a simple optimisation, showing that a welldesigned powerstructure can have structural performance comparable to a conventional design.The final section weighs the benefits of using a multifunctional structure against the potential disadvantages in terms of cost, design time and flexibility, as well as assessing the validity of assumptions made in the work. The conclusion is that a multifunctional structure of this type, whilst not worthwhile for all mission types, could potentially increase the feasibility of short-term spacecraft missions using small satellites (of the order of 100 kg) with large energy storage requirements

Can Carbassa: An off-grid solution for a rural home

This project aims to design an off-grid electrical installation based on renewable sources that can successfully solve the energy requirements of Can Carbassa, a rural home in the Alt Empordà. To do so the project is divided into four main chapters. In the first chapter the residence is described, along with its geographical location and climate. In the following chapter off-grid electrical installations are studied from a theoretical point of view, looking at the components that make up the system and what role they play in it, as well as the different technological solutions available on the market today. In the third chapter the current electrical installation is analysed to determine the current consumption and production and determining the weak points of the system. The conclusions of this analysis will be used in the following chapter to design the new installation, sizing all the components and defining the connections between them