Development of a cantilever beam generator employing vibration energy harvesting

This paper details the development of a generator based upon a cantilever beam inertial mass system which harvests energy from ambient environmental vibrations. The paper compares the predicted results from Finite Element Analysis (FEA) of the mechanical behaviour and magnetic field simulations and experimental results from a generator. Several design changes were implemented to maximise the conversion of magnetic energy into generated power and a maximum power output of 17.8µW was achieved at a resonant frequency of 56.6Hz and an applied acceleration of 60mg (g = 9.81ms-2)

Ineffectiveness of the consolidation provisions of the Transportation Act of 1920.

Thesis (M.B.A.)--Boston Universit

Investigation of the carbon and nitrogen stable isotope distribution in oil shales using stepped combustion analysis

The research undertaken falls into two sections; (I) the use of the technique of stepped combustion to investigate the carbon release properties and the distribution of the carbon stable isotopes within kerogens; and (ii) an assessment of the reproducibility and efficiency of the stepped combustion technique and a preliminary study of the technique for the investigation of the nitrogen release and nitrogen isotope distribution within oil shales. (i) A study has been made of the changes occurring in the carbon release and isotope profiles with increased maturation for a series of type II organic rich shales. This was complimented by the analysis of samples of type I kerogen which had been artificially matured using hydrous pyrolysis. Distinct changes in both the carbon release and isotope profiles were observed with increased natural maturity, implying a maturation process involving the cyclization and condensation of isotopically light aliphatic side chain material. Similar observations were made for the artificially matured samples. A series of shales which exhibit shifts in the ratio of the total organic carbon were analysed, in an attempt to determine whether or not this was a result of fluctuations in the contributions of isotopically distinct organic matter types. The analysis of one of the samples allowed two isotopically distinct organic components to be resolved; an isotopically heavy lower H/C ratio component and an isotopically lighter higher H/C ratio organic matter type. The fluctuations in the S13C ratio of the total organic carbon were able to be explained as a decrease in the S13C ratio of the higher H/C organic component with a possible contribution from the decrease in the amount of the lower H/C ratio component. (ii) A series of experiments was carried out to assess the reproducibility of the stepped combustion technique for types I and II organic matter. The variations observed in the reproduced carbon release and isotope profiles were small in comparison with the variations used as criteria for interpretation of the data. Analyses made using varying combustion periods, indicated that for types I and II organic matter, 60 minute combustion periods are necessary in order to obtain comparable results with bulk combustions of the sample. This is thought to be an effect of low oxygen pressure in the combustion vessel. The preliminary evaluation of the stepped combustion technique for the study of the nitrogen release and isotope profiles indicates that low oxygen pressure effects were more apparent during analyses on the nitrogen extraction line. This effect was more obvious for samples containing large amounts of organic carbon. Observations of the behaviour of the nitrogen release and isotope profiles were noted for small samples and lead to the conclusions that the major fraction of nitrogen occurs in aromatic sites in the kerpgen structure which are affected by the condensation processes of kerogen maturation. A decrease in the S15N of the total organic matter may occur with Increased maturation

Extensible sparse functional arrays with circuit parallelism

A longstanding open question in algorithms and data structures is the time and space complexity of pure functional arrays. Imperative arrays provide update and lookup operations that require constant time in the Random Access Machine (RAM) theoretical model, but it is conjectured that there does not exist a RAM algorithm that achieves the same complexity for functional arrays, unless restrictions are placed on the operations. The main result of this paper is an algorithm that does achieve optimal unit time and space complexity for update and lookup on functional arrays. This algorithm does not run on a RAM, but instead it exploits the massive parallelism inherent in digital circuits. The algorithm also provides unit time operations that support storage management, as well as sparse and extensible arrays. The main idea behind the algorithm is to replace a RAM memory by a tree circuit that is more powerful than the RAM yet has the same asymptotic complexity in time (gate delays) and size (number of components). The algorithm uses an array representation that allows elements to be shared between many arrays with only a small constant factor penalty in space and time. This system exemplifies circuit parallelism, which exploits large numbers of transistors per chip in order to speed up key algorithms. Extensible Sparse Functional Arrays (ESFA) can be used with both functional and imperative programming languages. The system comprises a set of algorithms and a circuit specification, and it has been implemented on a GPGPU

Regular expressions as violin bowing patterns

String players spend a significant amount of practice time creating and learning bowings. These may be indicated in the music using up-bow and down-bow symbols, but those traditional notations do not capture the complex bowing patterns that are latent within the music. Regular expressions, a mathematical notation for a simple class of formal languages, can describe precisely the bowing patterns that commonly arise in string music. A software tool based on regular expressions enables performers to search for passages that can be handled with similar bowings, and to edit them consistently. A computer-based music editor incorporating bowing patterns has been implemented, using Lilypond to typeset the music. Our approach has been evaluated by using the editor to study ten movements from six violin sonatas by W. A. Mozart. Our experience shows that the editor is successful at finding passages and inserting bowings; that relatively complex patterns occur a number of times; and that the bowings can be inserted automatically and consistently

Photoluminescence of near-lattice-matched GaN/AlInN quantum wells grown on free-standing GaN and on sapphire substrates

Near-lattice-matched GaN/Al1−xInxN single quantum wells, grown using both free-standing GaN and conventional GaN-on-sapphire substrates, are studied by photoluminescence (PL) and PL excitation spectroscopies. PL spectra distinguish luminescence originating in the wells, barriers, and underlying GaN buffer layers. The spectra also reveal significant differences between structures grown simultaneously on the different substrates. The quantum well transition energy decreases as the well width increases due to the intense in-built electric fields, estimated to be 3.0±0.5 MeV/cm, that persist in strain free GaN/Al1−xInxN. Screening of these fields is studied using the excitation power dependence of the P

Airflow limitation or static hyperinflation: which is more closely related to dyspnea with activities of daily living in patients with COPD?

<p>Abstract</p> <p>Background</p> <p>Dyspnea while performing the activities of daily living has been suggested to be a better measurement than peak dyspnea during exercise. Furthermore, the inspiratory capacity (IC) has been shown to be more closely related to exercise tolerance and dyspnea than the FEV₁, because dynamic hyperinflation is the main cause of shortness of breath in patients with COPD. However, breathlessness during exercise is measured in most studies to evaluate this relationship.</p> <p>Purpose</p> <p>To evaluate the correlation between breathlessness during daily activities and airflow limitation or static hyperinflation in COPD.</p> <p>Methods</p> <p>We examined 167 consecutive outpatients with stable COPD. The Baseline Dyspnea Index (BDI) was used to evaluate dyspnea with activities of daily living. The relationship between the BDI score and the clinical measurements of pulmonary function was then investigated.</p> <p>Results</p> <p>The Spearman rank correlation coefficients (Rs) between the BDI score and the FEV₁(L), FEV₁(%pred) and FEV₁/FVC were 0.60, 0.56 and 0.56, respectively. On the other hand, the BDI score also correlated with the IC, IC/predicted total lung capacity (TLC) and IC/TLC (Rs = 0.45, 0.46 and 0.47, respectively). Although all of the relationships studied were strongly correlated, the correlation coefficients were better between dyspnea and airflow limitation than between dyspnea and static hyperinflation. In stepwise multiple regression analyses, the BDI score was most significantly explained by the FEV₁(R²= 26.2%) and the diffusion capacity for carbon monoxide (R²= 14.4%) (Cumulative R²= 40.6%). Static hyperinflation was not a significant factor for clinical dyspnea on the stepwise multiple regression analysis.</p> <p>Conclusion</p> <p>Both static hyperinflation and airflow limitation contributed greatly to dyspnea in COPD patients.</p

Ineffectiveness of the consolidation provisions of the Transportation Act of 1920.

Thesis (M.B.A.)--Boston Universit