Active vibration control (AVC) of a satellite boom structure using optimally positioned stacked piezoelectric actuators

In this paper, results for active vibration control predicted from experimental measurements on a lightweight structure are compared with purely computational predictions. The structure studied is a 4.5m long satellite boom consisting of 10 identical bays with equilateral triangular cross sections. First, the results from a Fortran code that is based on a receptance analysis are validated against the experimental forced response of the boom structure. Exhaustive searches are then carried out to find the optimum positions for one and two actuators. Finally, a genetic algorithm is employed to find high-quality positions for three actuators on the structure that will achieve the greatest reductions in vibration transmission. Having found these actuator positions, experiments are then carried out to verify the quality of the theoretical predictions. It was found that the attenuation achievable in practice for one, two and three actuators were, respectively, 15.1, 26.1 and 33.5 dB

Active vibration control (AVC) of a satellite boom structure using optimally positioned stacked piezoelectric actuators

In this paper, results for active vibration control predicted from experimental measurements on a lightweight structure are compared with purely computational predictions. The structure studied is a 4.5m long satellite boom consisting of 10 identical bays with equilateral triangular cross sections. First, the results from a Fortran code that is based on a receptance analysis are validated against the experimental forced response of the boom structure. Exhaustive searches are then carried out to find the optimum positions for one and two actuators. Finally, a genetic algorithm is employed to find high-quality positions for three actuators on the structure that will achieve the greatest reductions in vibration transmission. Having found these actuator positions, experiments are then carried out to verify the quality of the theoretical predictions. It was found that the attenuation achievable in practice for one, two and three actuators were, respectively, 15.1, 26.1 and 33.5 dB

Lives lived ‘at such a distance’: How distance shaped masculinity and femininity in the British Atlantic, c.1660-1760

This thesis explores the role distance played in shaping British masculinity and femininity in the early modern British Atlantic world. Focusing on gender as a foundation of individual identity, this research outlines the powerful effects of Atlantic crossings, maritime trade networks, and encounters with new landscapes and nations. It covers a century of colonial expansion across North America and the Caribbean, from the Restoration to the Seven Years’ War. Building on an earlier study of Anglo-Virginian planter William Byrd II (1674-1744), this thesis uses a series of interconnected individuals as case studies. It explores these individuals’ experiences through five key dynamics: credit, seafaring, communication and emotions, settler-Indigenous encounters, and race. This approach builds on prosopography, the ‘serial microhistory’ approach developed by Kristen Block, and Atlantic history more widely. Responding to historiographical questions posed by Susan Amussen, Allyson Poska, and Julie Hardwick, it draws on diverse fields of study. These include geography, maritime history, the spatial turn, studies of emotion, intersectional analysis, Indigenous scholarship, and gender studies. This thesis explores how distance and interaction created ‘Atlantic masculinities’ in Britain and its colonies. Furthermore, it asks if complementary or divergent ‘Atlantic femininities’ can be found in this period. In summary, this research shows how the ‘New World’ produced new identities over a century of British imperial expansion

Improving seabed cable plough performance for offshore renewable energy

Seabed ploughing plays an important part in providing protection to subsea cables that connect offshore renewables, and the process represents a significant portion of the overall installation cost. Current models for predicting the required tow forces for seabed ploughs are based on semi-empirical methods as conventional geotechnical finite element analysis is not suited to modelling this process due to the large de-formations involved. The project described in this paper aims to develop a new material point method numerical modelling software to predict seabed plough response, which will enable new designs to be optimised. This will be validated against physical modelling, a part of which is the focus of this paper. This includes both 1g and centrifuge testing as well as new techniques such as 3D soil surface scanning. The testing also provides insights into share geometry influences on plough behaviour, and will allow improvements to existing empirical models

Evaluation of pathologic staging using number of nodes in p16-negative head and neck cancer

Objectives: The 8th edition AJCC staging guidelines for head and neck squamous cell carcinoma (HNSCC) recently introduced pathologic staging criteria for nodal disease among p16-positive patients. In this study we evaluate pathologic staging in p16-negative HNSCC. Materials and Methods: We compared pathologic staging to the 7th and 8th edition AJCC staging systems using a statewide population-based cohort. All M0 p16-negative surgical patients were included. The outcome was five-year overall survival. Results: Of 304 patients identified, 113 were N0, 157 had 1–4 positive nodes, and 34 had ≥4 nodes. Survival was 71% (95% CI 61–78%) with no nodes, 48% (36%−60%) for 1–4 nodes, and 24% (11 – 39%) for > 4 nodes. When compared to the AJCC systems, the pathologic staging yielded a larger total survival gradient, more montonic survival, better consistency across primary sites, and a slightly lower Bayesian information criterion (1510 vs 1538). After adjusting for disease characteristics, demographics, and tobacco use, hazard ratios for survival were similar using pathologic and AJCC criteria. Conclusion: In this cohort, pathological staging was more prognostic than AJCC staging. This is the first study to evaluate pathologic staging in p16-negative cancer; if these findings are verified, a universal nodal staging system could be introduced