The numerical solution of the dynamic fluid-structure interaction problem.

Merged with duplicate record 10026.1/2055 on 12.04.2017 by CS (TIS)In this thesis we consider the problem of the dynamic fluid-structure interaction between a finite elastic structure and the acoustic field in an unbounded fluid-filled exterior domain. We formulate the exterior acoustic problem as an integral equation over the structure surface. However, the classical boundary integral equation formulations of this problem do not have unique solutions at certain characteristic frequencies (which depend on the surface) and it is necessary to employ modified boundary integral equation formulations which are valid for all frequencies. The modified integral equation formulation used here involves certain arbitrary parameters and we shall study the effect of these parameters on the stability and accuracy of the numerical methods used to solve the integral equation. We then couple the boundary element analysis of the exterior acoustic problem with a finite element analysis of the elastic structure to investigate the interaction between the structure and the acoustic field. Recently there has been some controversy over whether or not the coupled problem suffers from the non-uniqueness problems associated with the classical integral equation formulations of the exterior acoustic problem. We resolve this question by demonstrating that the solution to the coupled problem is not unique at the characteristic frequencies and that we need to employ an integral equation formulation valid for all frequencies. We discuss the accuracy of our numerical results for both the acoustic problem and the coupled problem, for a number of axisymmetric and fully three-dimensional problems. Finally, we apply our method to the problem of a piezoelectric sonar transducer transmitting an acoustic signal in water, and observe reasonable agreement between our theoretical predictions and some experimental results.Admiralty Research Establishment, Portlan

Ecology and foreign policy : theoretical lessons from the literature

A comprehensive understanding of international environmental politics requires attention to foreign policy. In this essay we describe many of the most prominent—and some of the less prominent—theories and approaches to foreign policy and international relations, with emphasis on how they can help us to better understand foreign policy in the environmental issue area. We organize the theories into three categories: systemic theories, which emphasize the influence of the international system, including the distribution of power within it; societal theories, which focus our attention on domestic politics and culture; and state-centric theories, which find answers to questions about foreign policy within the structure of the state and the individuals who promulgate and implement foreign policies in the name of a given country. Within this presentation of various theories, we highlight the influence of power, interests and ideas

The Aggressive Driving Behavior Scale: Developing a Self-Report Measure of Unsafe Driving Practices

The purpose of this study was to investigate the reliability and validity of a new 11-item measure of aggressive driving, the Aggressive Driving Behavior Scale, which focuses on behaviors rather than cognitions, emotions, or motivational states. Based on a sample of 200 undergraduates, 111 women and 89 men), the study examined the convergent validity of the new scale with measures of hostility, hypercompetitiveness, and aggressive thoughts and emotions experienced during driving. A principal component analysis of the Aggressive Driving Behavior Scale (alpha = .80) yielded two factors that form reliable subscales labeled Speeding and Conflict Behavior. As expected, the total scale and the two subscales correlated with hostility, hypercompetitiveness, as well as aggressive driving-related thoughts and emotions. The results suggest that the scale can be used as a research tool and a self-assessment instrument

Recklessness in context: Individual and situational correlates to aggressive driving

Traffic-related injury and fatality are major health risks in the United States and worldwide. One contributor to road accidents is unsafe and aggressive driving practices. We examined individual and situational aspects of aggressive driving by having 152 undergraduate students complete self-report measures. Aggressive driving was related to personality variables, such as hostility, sensation seeking, and competitiveness, as well as to social variables such as driving without passengers and characteristics of the target vehicle (e.g., passengers, age, and status of driver), environmental variables (e.g., type of road, traffic, and weather), and temporal variables (e.g., time pressure and time of day)

A reliability analysis of the Revised Competitiveness Index

This study examined the reliability of the Revised Competitiveness Index by investigating the test-retest reliability, interitem reliability, and factor structure of the measure based on a sample of 280 undergraduates (200 women, 80 men) ranging in age from 18 to 28 years (M=20.1, SD=2.1). The findings indicate that the Revised Competitiveness Index has high test-retest reliability, high interitem reliability, and a stable factor structure. The results support the assertion that the Revised Competitiveness Index assesses competitiveness as a stable trait rather than a dynamic state

Blended Learning: Overview and Recommendations for Successful Implementation

Purpose – The purpose of this paper is to identify key themes within the blended learning literature and to develop a series of practical recommendations to facilitate the successful adaptation and implementation of a ‘‘blended approach to learning delivery’’. Design/methodology/approach – The literature was reviewed and informed a series of recommendations for organisations considering adopting or implementing blended approaches to teaching and training. Findings – Several key themes centering on the importance of evaluation, skills training, pedagogy, human factors, technology and implementation were identified. The emerging themes informed a series of practical recommendations to assist organisations considering blended learning approaches. Findings highlight the current limitations in the evidence base. Practical implications – The identified key themes and practical recommendations provide a useful assist to organisations considering adopting and implementing blended approaches to teaching and training. Originality/value – The paper highlights key areas for development in the blended learning literature and at the organisational level

Introduction, dispersal and naturalisation of the Manila clam Ruditapes philippinarum in British estuaries, 1980-2010

The introduction of the Manila clam into British coastal waters in the 1980s was contested by conservation agencies. While recognizing the value of the clam for aquaculture, the government decided that it posed no invasive risk, as British sea temperatures would prevent naturalization. This proved incorrect. Here we establish the pattern of introduction and spread of the species over the first 30 years of its presence in Britain. We report archival research on the sequence of licensed introductions and examine their relationship in time and space to the appearance of wild populations as revealed in the literature and by field surveys. By 2010 the species had naturalized in at least 11 estuaries in southern England. These included estuaries with no history of licensed introduction. In these cases activities such as storage of catch before market or deliberate unlicensed introduction represent the probable mechanisms of dispersal. In any event naturalization is not an inevitable consequence of introduction and the chances of establishment over the period in question were finely balanced. Consequently in Britain the species is not currently aggressively invasive and appears not to present significant risk to indigenous diversity or ecosystem function. However it is likely to gradually continue its spread should sea surface temperatures rise as predicted

Nineteen-hundred and seventy-four

For my work I use clay as the initial medium, laid up on armatures, or built in the hand if size permits. I choose clay because it is very plastic, reusable, fairly durable when fired; and molds can be taken from it for casting in more durable materials. I find that as I come to understand clay, I am able to achieve greater technical flexibility and broaden the parameters of my conception. I choose the head because it seems to articulate practically everything about the figure in a form of "shorthand". The head has the ability to focus the particular kinds of energy that the body expresses. Eric Ambler wrote: A man's features, the bone structure and the tissue which covers it, are the product of a biological process; but his face he creates for himself. It is a statement of his habitual emotional attitude; the attitude which his desires need for their fulfillment and which his fears demand for their protection from prying eyes It is a screen to his mind's nakedness. Only a few men, painters, have been able to see the mind through the face. I see the head, or face, as the ultimate expression of not only man's mind, but soul as well. I am interested in exploring the "poetry of being" in the latter part of the Twentieth Century as our civilization approaches the third millennium. I choose models for their availability and their face, which comes to the surface of the crowd

Bony abnormalities of the hip joint: a new comprehensive, reliable and radiation-free measurement method using magnetic resonance imaging

The objective of this study was to develop comprehensive and reliable radiation-free methods to quantify femoral and acetabular morphology using magnetic resonance imaging (MRI). Thirty-two hips [16 subjects, 6 with intra-articular hip disorder (IAHD); 10 controls] were included. A 1.5-T magnetic resonance system was used to obtain three-dimensional fat-suppressed gradient-echo images at the pelvis and distal femora. After acquisition, pelvic images were post-processed to correct for coronal, axial and sagittal rotation. Measurements performed included acetabular version (AV), femoral version (FV), lateral center-edge angle (LCEA), femoral neck angle (FNA) and alpha angle (AA) at 3, 2, 1 and 12 a.m. Two experienced raters, a musculoskeletal radiologist and an orthopedic physical therapist, and a novice rater, a research assistant, completed reliability testing. Raters measured all hips twice with minimum 2 weeks between sessions. Intra-class Correlation Coefficients (ICCs) were used to determine rater reliability; standard error of measurements was reported to estimate the reasonable limits of the expected error in the different raters’ scores. Inter-rater reliability was good to excellent for all raters for AV, FV, FNA and LCEA (ICCs: 0.82–0.98); good to excellent between experienced raters (ICCs: 0.78–0.86) and poor to good between novice and experienced raters (ICCs: 0.23–0.78) for AA. Intra-rater reliability was good to excellent for all raters for AV, FV and FNA (ICCs: 0.93–0.99); for one experienced and novice rater for LCEA (ICCs: 0.84–0.89); moderate to excellent for the experienced raters for AA (ICCs: 0.72-0.89). Intra-rater reliability was poor for the second experienced rater for LCEA (ICC: 0.56), due to a single measurement error and for the novice rater for AA (ICCs: 0.17–0.38). We described MRI methods to comprehensively assess femoral and acetabular morphology. Measurements such as AV, FV and FNA and the LCEA can be made reliably by both experienced and novice raters; however, the AA measurement was reliable only among experienced raters