1,584 research outputs found
Supplemental Material - Cervical Spine Motion Requirements From Night Vision Goggles May Play a Greater Role in Chronic Neck Pain than Helmet Mass Properties
No full textSupplemental Material for Cervical Spine Motion Requirements From Night Vision Goggles May Play a Greater Role in Chronic Neck Pain than Helmet Mass Properties by Jeff M. Barrett, Laura A. Healey, Steven L. Fischer and Jack P. Callaghan in Human Factors</p
From the ‘freedom of the streets’: a biographical study of culture and social change in the life and work of writer Jack Common (1903-1968)
No full textThe author assesses the life and work of the Newcastle upon Tyne born writer Jack Common in the light of the massive social, economic and cultural changes which have affected the North East of England and wider society through the period of Common's life and afterwards. He seeks to point out the relevance of Common to the present day in terms of his ideas about class, community and the individual and in the light of Common's sense of rebelliousness influenced by a process of grass-roots education and self-improvement. In addition, he draws upon his own extensive experience in community arts and education, looking, in particular, at the work he and others have carried out on Common over the last thirty years and assessing its value in the light of recent political changes. The author draws together the range of biographical and literary criticism carried out by a range of individuals over this period of time and brings into print hitherto unpublished material about Common's life and work by interviewing family members and associates, exploring the Common Archive at Newcastle University and other largely ignored sources, and studying Common's significant association with George Orwell in great detail. Through all of this, he seeks to argue that Common's life and ideas remain worthy of close attention in the present day
An experimental and numerical study on jack-up dynamic behavior
No full textThis paper presents the more salient results of an experimental and numerical study on jack-up dynamic behavior. The laboratory studies of three principle jack-up platform models were carried out in both regular and irregular waves. The data from irregular wave tests were analyzed in both the probability domain and frequency domain supported by a careful error analysis. Computer simulations were carried out in the time domain using a nonlinear, dynamic, multiple degree of freedom software which includes various hydrodynamic interaction options. The experimental results and associated computer simulations demonstrate that nonlinearities are important even with the present simplified model testing and different nonlinearities have different (sometimes compensating) influences on the structure's dynamic behavior. Some more specific results include: (1) The stiffness obtained from static tests can be significantly lower than that inferred from dynamic vibration tests; (2) relative motions from structural compliance are such that they cannot be responsibly neglected in the hydrodynamic computation; and (3) inclusion of the P-O effect in the structural schematization is essential for the jack-up simulations.Offshore TechnologyCivil Engineering and Geoscience
A procedure for determining parameters of a simplified ligament model
No full textThe final publication is available at Elsevier via http://dx.doi.org/10.1016/j.jbiomech.2017.10.037 © 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/A previous mathematical model of ligament force-generation treated their behavior as a population of collagen fibres arranged in parallel. When damage was ignored in this model, an expression for ligament force in terms of the deflection, x, effective stiffness, k, mean collagen slack length, μ, and the standard deviation of slack lengths, σ, was obtained. We present a simple three-step method for determining the three model parameters (k, μ, and σ) from force-deflection data: (1) determine the equation of the line in the linear region of this curve, its slope is k and its x -intercept is -μ; (2) interpolate the force-deflection data when x is -μ to obtain F0; (3) calculate σ with the equation σ=2πF0/k. Results from this method were in good agreement to those obtained from a least-squares procedure on experimental data – all falling within 6%. Therefore, parameters obtained using the proposed method provide a systematic way of reporting ligament parameters, or for obtaining an initial guess for nonlinear least-squares.Jack P. Callaghan is supported by the Tier 1 Canada Research Chair in Spine Biomechanics
Jeff M. Barrett is supported by an NSERC PGS-D Scholarshi
Not by Humans Alone: Environments of Marginal Significance in Late Imperial China and Beyond
No full textThe panel considers the historical significance of human ties with key elements of surrounding environments, particularly terrain and fauna, for a more diversified study of Late Imperial China across its geographic and cultural margins. These elements are analyzed as manifestations of dynamic conditions not fully subject to human control and so require adaptive responses from people. So, Manchu identity depends in part on fulfilling the needs of garrison horses for pasturage in China proper; the ecological dynamics of Yangzi upstream clearance create partly insoluble administrative problems downstream; long distance human commercial caravan traffic linking Burma and China needs mules, who in turn need their muleteers to be more vets than merchants; the Wuling mountains at Guizhou and Huguang help keep indigenous Miao identity free of full Ming imperial authority, weighed down by the dynasty’s “Southern Great Wall.” The discussant will provide further context to show how the products of such relations resonate beyond the Late Imperial period into the twentieth century. Overall, the panel adopts more environmentally inclusive perspectives linking China proper to its borderlands to show how cultural significance is, often inadvertently, realized “not by humans alone.”Jack P Hayes did the Introduction & was a Panel Discussant. Association of Asian Studies Annual Meeting (Spring 2014). Philadelphia, PA
Design and testing of a thick-film dual-modality sensor for composition measurements in heterogeneous mixtures
No full textThe current paper focuses on design and laboratory evaluation of a dual-modality sensor, developed for the needs of oil and gas extraction industry to measure the composition of heterogeneous mixtures in harsh conditions. The sensor combines ultrasonic and electrical measurement techniques, which are non-destructive, rapid and can potentially provide an on-line industrial measurement. Such a ‘dual-modality’ measurement could potentially be reliable in a wider range of process conditions. A distinct feature of the sensors presented here is their construction, which makes use of the thick-film technology, enabling the construction of multi-layered structures of both conductive and non-conductive layers, some of which may exhibit piezoelectric properties for ultrasonic measurement purposes. These are later fired on a ceramic substrate to provide rugged sensors, capable of working in aggressive industrial environments. Laboratory experiments to investigate the feasibility of the dual-modality sensors were conducted and some comparisons with the theoretical predictions are presented
Workability study for going-on-location of jack-up vessels
No full textThis thesis focuses on the going-on-location (GoL) operation of jack-up vessels in the offshore wind energy industry. The GoL process involves the transition of a jack-up vessel from a free-floating state to a state where it’s elevated above the waterline and pinned to the seabed. The workability of these vessels is significantly affected by the impact loads experienced during the GoL process, particularly when interacting with stiff seabeds and non-negligible sea states. In current methodologies, certain parameters like wave height and wave period set the limitations to when GoL process can proceed. For safety reasons, the GoL process is halted if these conditions are exceeded. Instead of solely depending on external factors like wave height an wave period, the focus transitions towards how the vessel dynamics relate to the impact forces it encounters during the GoL. To address this limitation, a comprehensive framework has been developed that combines hydrodynamic, structural, and soil-spudcan interaction elements to evaluate impact forces during the GoL process. The framework offers a flexible and case-specific configuration. It allows for easy modifications, integration, andreplacement of components and input parameters. This case-specific arrangement is advantageous due to the wide range of jack-up vessels and environmental variations. In model implementations adhering to the framework, the jack-up vessel is represented as a multi-body structure, in contrast to the conventional rigid-body representation often employed. Within the multibody approach the spudcans, the legs, and the vessel are described by separate bodies each with its own properties. The primary focus of this research is on the dynamic soil-spudcan interaction process, which has not been extensively covered in existing standards. The soil-spudcan interaction model is to determine the instantaneous force acting on the spudcan as it contacts the seabed during GoL. By integrating elasto-plastic soil behavior into thesoil-spudcan interaction element, the model encompasses descriptions of soil resistance to spudcan penetration and lateral displacement, taking into account memory and potentially stateful characteristics. A simulation model, adhering to the framework, has been developed, integrating hydromechanical, structural,and soil-spudcan interaction submodels within the Orcaflex environment. Three distinct simulation scenarios are examined: an undisturbed vessel (free-floating), a disturbed vessel (full GoL), and a pinned vessel (elevatedjack-up). The disturbed vessel scenario, which includes a full GoL process, has exhibited consistency in both undisturbed vessel simulations, where the vessel is the free-floating stage, and in pinned vessel simulations,where the vessel is in the pinned stage. The impact phase is situated between these two boundary cases, and the framework effectively represents simulation models within its scope. In addition, simulations with varying sea states are performed for regular and irregular sea states. Simulations involving varying regular wave patterns suggest that the maximum downward spudcan velocity (DSV) is a critical parameter influencing the magnitude of impact forces on the spudcans. For irregular waves, the simulations indicate that the maximum impact forces are more closely related to the pinned vessel scenario, asthe maximum impact occurs towards the end of the impact phase.In conclusion, this thesis has effectively described the behavior of jack-up vessels during the impact phase of the GoL process. For any model utilizing the framework, the GoL process can be simulated, and the resultscan be analyzed to assess workability. Furthermore, the study proposes a potential correlation between vessel dynamics and maximal impact forces, a relationship that could potentially guide on-board decision-makingprocesses. The enhanced understanding of the interaction between the spudcan and the seabed, along with the comprehensive framework, contributes to improving the decision-making process for executing the GoLoperation of jack-up vessels in the offshore wind energy industry.Offshore and Dredging Engineerin
British communism : a documentary history
No full textWide-ranging and richly researched, this is the first sourcebook to reconstruct the tumultuous history of the Communist Party of Great Britain. Drawing together over one hundred and fifty documents, including party statements, press releases, published correspondence, reviews, poems and articles, it presents a detailed portrait of theparty, its abiding concerns and its many contradictions from the 1920s to the 1980s. It samples voices from the full spectrum of the party’s diverse personnel, from long-standing party leaders (Harry Pollitt, Rajani Palme Dutt), to prominent twentieth-century British intellectuals (E. P. Thompson, Eric Hobsbawm), to significant cultural figures (Jack Lindsay, Alan Bush, A. L. Lloyd). Over half of the book is organised chronologically, bringing intosharp focus the CPGB’s trajectory: its emergence and consolidation; the adoption of new lines in response to shifting international contexts and Moscow directives; moments of damaging crisis and political isolation; the widening fault lines that eventually led to theparty’s dissolution. Running through this overarching narrative are thematic chapters providing magnified coverage of central issues: the party’s critique of imperialism and engagement with anticolonial struggles; the party’s cultural policies and interventions; its relationship with the Soviet Union and the broader British Labour movement. Balanced, comprehensive and framed by Callaghan and Harker’s detailed introductions, British Communism: A documentary history is not only a valuable addition to the historiography of Communism, but to the study of twentieth-century Britain
Automated Histological Analysis System for Quantifying Microstructural Damage Accumulation to the Annulus Fibrosus
No full textBen Daya, I., Noguchi, M., Callaghan, J. P., & Wong, A. (2016). Automated Histological Analysis System for Quantifying Microstructural Damage Accumulation to the Annulus Fibrosus. Journal of Computational Vision and Imaging Systems, 2(1). Retrieved from http://openjournals.uwaterloo.ca/index.php/vsl/article/view/100In this paper, we proposed an automated histological analysis system for quantifying microstructural damage accumulation to the annulus fibrosus. This system takes in a digital histology image and uses Gaussian mixture model based segmentation, followed by connected components analysis to extract and label possible clefts. The image is then refined through spatial and size constraints. Finally, the required statistics for quantifying microstructural damage are calculated.This research was funded by the Natural Sciences and Engineering Research Council of Canada, the Canada Research Chairs Program, and the Ontario Ministry of Research and Innovation
The Role of Low Back Capacities on Loaded and Unloaded Functional Movements: Squat and Lunge
No full textVariability of movement patterns across individuals have been well documented in healthy young adults. Large heterogeneity of movement patterns within seemingly homogenous populations suggests the possible presence of subgrouping of individuals. This variability makes it difficult to study and draw conclusions based on group effects, since group means may not be representative of individuals within the group, and especially when subgroups respond differently to interventions. It is also well established that certain movements and movement characteristics are relevant to movement efficiency, tissue exposure, and injury risk, however, it is not fully understood why individuals utilize certain movement patterns over others. It is plausible that physical capacity related differences between subgroups of individuals can help explain differences in movement. As such, this thesis aimed to cluster individuals according to their lumbar movement profiles during functional movements, and then relate characteristic profiles of each subgroup to the low back capacities of strength, muscular endurance, proprioception, and motor control. Additionally, this thesis investigated the effects of introducing a moderate challenge (i.e., loading) to the lumbar movement profiles during functional movements.
Thirty-two healthy young adults (16 M, 16 F) performed two sets of ten repetitions each of squat (SQT) and lunge (LNG) in both unloaded (UL) and loaded (LD) conditions. Additionally, lumbar capacity tests of strength (S), endurance (E), joint position accuracy (P-A), joint position sensitivity (P-S), and motor control (MC) were assessed. State spaces of lumbar angle dynamics for each condition of movement were constructed, then discretized into 48 bins and averaged across repetitions. State spaces were then analyzed using spectral clustering with the number of subgroups selected based on the strongest silhouette score. Analyses of variance (ANOVAs) testing the effect of sex and group on each capacity test’s scores were conducted.
The results of the clustering produced two groups with weak clustering strength in each condition. In both the SQT UL and SQT LD conditions, a significant interaction between sex and group in P-S (p = 0.01), and a significant effect of sex in E (p = 0.04)were found. In the LNG UL condition, a significant interaction between sex and group in P-A (p = 0.04), and a significant effect of sex in E (p = 0.04) were found. Significant interactions between group and sex were found in both P-S (p = 0.04) and MC (p = 0.03) for the LNG LD condition. Differences in lumbar capacities between groups were related to features of the state spaces, including shape, diffuseness, and intensity of attractors.
This thesis highlighted the importance of physical capacities on movement patterns and affirmed the necessity of characterizing subgroups of individuals within a heterogeneous sample population. This thesis provides a framework for more comprehensive investigations into the relationships between specific capacities and movement profiles
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