Книги з теми "Shape deformation"

Assessing the right ventricle by any imaging modality is a challenge because of the thin wall and crescent shape that wraps around the left ventricle. Structured echocardiographic examination using two-dimensional imaging provides a detailed regional and global qualitative assessment for routine evaluation. Quantitation is possible using one or more methods including tricuspid annulus plane systolic excursion, fractional area change, and myocardial performance index but speckle tracking deformation imaging and three-dimensional echocardiography are emerging as more robust quantitative methods. Right ventricular pressures should also be estimated routinely as long as a clear tricuspid regurgitant jet is identified.

The study of joint morphology can help us to understand the risk factors for osteoarthritis (OA), how it progresses, and aids in developing imaging biomarkers for study of the disease. OA results in gross structural changes in affected joints. Growth of osteophytes, deformation of joint components, and loss of joint space where cartilage has broken down are all characteristics of the disorder. Certain bone shapes as well as malalignment predispose people to future OA, or may be a marker for early OA. Geometrical measures, such as the alpha angle or Wiberg’s CE angle, used to be the primary tool for investigating morphology. In recent years, however, statistical shape modelling (SSM) has become increasingly popular. SSM can be used with any imaging modality and has been successfully applied to a number of musculoskeletal conditions. It uses sets of landmark points denoting the anatomy of one or more bones to generate new variables (modes) that describe and quantify the shape variation in a set of images via principal components analysis. With the aid of automated search algorithms for point placement, the use of SSMs is expanding and provides a valuable and versatile tool for exploration of bone and joint morphometry. Whilst the majority of research has focused on hip and knee OA, this chapter provides an overview of joint morphology through the whole skeleton and how it has helped our ability to understand and quantify the risk and progression of osteoarthritis.

Art historian Tobin Siebers has recently argued that modern visual art is centrally concerned with representing and finding new sorts of beauty in the fractured, disfigured, disabled human body. This essay asks whether the modern in music manifests itself as disability. Focusing on the Stravinskian strand of musical modernism and taking the second of his Three Pieces for String Quartet as a case study, this essay notes that the music can be understood as representing disability in its shape and appearance, its movements, and its implicit mental capacity and affect. Stravinsky’s description of this music as his effort to represent musically the appearance and “the jerky, spastic movements” of a famous music hall performer, Little Tich, whose small stature was perceived by contemporary observers as a grotesque deformation, suggests the music may be understood not only to represent disability generically and metaphorically but also to represent a particular disabled body.

Echocardiography is a key diagnostic method in the management of patients with cardiomyopathies.The main echocardiographic findings of hypertrophic cardiomyopathy are asymmetric hypertrophy of the septum, increased echogenicity of the myocardium, systolic anterior motion, turbulent left ventricular (LV) outflow tract blood flow, intracavitary gradient of dynamic nature, mid-systolic closure of the aortic valve and mitral regurgitation. The degree of hypertrophy and the magnitude of the obstruction have prognostic meaning. Echocardiography plays a fundamental role not only in diagnostic process, but also in management of patients, prognostic stratification, and evaluation of therapeutic intervention effects.In idiopathic dilated cardiomyopathy, echocardiography reveals dilation and impaired contraction of the LV or both ventricles. The biplane Simpson’s method incorporates much of the shape of the LV in calculation of volume; currently, three-dimensional echocardiography accurately evaluates LV volumes. Deformation parameters might be used for detection of early ventricular involvement. Stress echocardiography using dobutamine or dipyridamole may contribute to risk stratification, evaluating contractile reserve and left anterior descending flow reserve. LV dyssynchrony assessment is challenging and in patients with biventricular pacing already applied, optimization of atrio-interventricular delays should be done. Specific characteristics of right ventricular dysplasia and isolated LV non-compaction can be recognized, resulting in an increasing frequency of their prevalence. Rare forms of cardiomyopathy related with neuromuscular disorders can be studied at an earlier stage of ventricular involvement.Restrictive and infiltrative cardiomyopathies are characterized by an increase in ventricular stiffness with ensuing diastolic dysfunction and heart failure. A variety of entities may produce this pathological disturbance with amyloidosis being the most prevalent. Storage diseases (Fabry, Gaucher, Hurler) are currently treatable and early detection of ventricular involvement is of paramount importance for successful treatment. Traditional differentiation between constrictive pericarditis (surgically manageable) and the rare cases of restrictive cardiomyopathy should be properly performed.

This chapter explores how Lao She performs an affective mapping of his warped native city’s streets, courtyard houses, ditch, and teahouse: everyday tyranny and despair in the phantasmal and entrapping avenues and streets; wartime atlas of emotions including nostalgia, mourning, shame, anger, and hatred; socialist sentiment and citizenship born in the ideological/ecological representation of Dragon Beard Ditch as a metamorphic space; and self-mourning in a warped and wounded teahouse as a distorted space-time continuum, a shrinking and pessimistic miniature of old Beijing misery and a sign of unfathomable urban darkness. Confronting the advent, expansion, and menace of modernity as well as the whirlwind and whirlpool of political and historical change, Manchu writer Lao She envisions modern Beijing as the locus of pain and pleasure, dystopia and dreamland, moral decline and physical performance, material deformations and emotional vicissitudes.

Extrusion, Second Edition provides a complete and thorough overview of the processes, equipment, and tooling used to extrude metals into desired shapes and forms. It covers all types of processes, including direct, indirect, and hydrostatic extrusion, cable sheathing, continuous extrusion, and the extrusion of powder metals. It describes each process in detail, explaining how the associated forces, stresses, displacements, and heat cause metals to deform and flow and how it affects the microstructure and properties of the resulting products. It discusses the design, setup, and control of extrusion equipment, the use of lubricants and shells, the effect of tooling materials and geometries, and the practical implications of material flow, friction, discard length, and exit temperature. It describes the deformation and extrusion behaviors of many materials, the product forms into which they can be made, and related processing requirements. The book also provides detailed application examples, an introduction to quality management, a review of the basics of metallurgy, and experimentally measured extrusion data. For information on the print version, ISBN 978-0-87170-837-3, follow this link.

There is a deep analogy between the physics of crystalline solids and the behaviour of superfluids, dating back to the pioneering work of Phillip Anderson, Paul Martin, and others. The stiffness to shear deformations in a periodic crystal resembles the super-fluid density that controls the behaviour of supercurrents in neutral superfluids such as He4. Dislocations in solids have a close analogy with quantized vortices in superfluids. Remarkable recent experiments on the way rod-shaped bacteria elongate their cell walls have focused attention on the dynamics and interactions of point-like dislocation defects in partially-ordered cylindrical crystalline monolayers. In these lectures, we review the physics of superfluid helium films on cylinders and discuss how confinement in one direction affects vortex interactions with supercurrents. Although there are similarities with the way dislocations respond to strains on cylinders, important differences emerge due to the vector nature of the topological charges characterizing the dislocations.

The aim of the paper was to determine the influence of root systems of chosen tree species found in the Polish Flysch Carpathians on the increase of soil shear strength (root cohesion) in terms of slope stability. The paper's goal was achieved through comprehensive tests on root systems of eight relatively common in the Polish Flysch Carpathians tree species. The tests that were carried out included field work, laboratory work and analytical calculations. As part of the field work, the root area ratio (A IA) of the roots was determined using the method of profiling the walls of the trench at a distance of about 1.0 m from the tree trunk. The width of the. trenches was about 1.0 m, and their depth depended on the ground conditions and ranged from 0.6 to 1.0 m below the ground level. After preparing the walls of the trench, the profile was divided into vertical layers with a height of 0.1 m, within which root diameters were measured. Roots with diameters from 1 to 10 mm were taken into consideration in root area ratio calculations in accordance with the generally accepted methodology for this type of tests. These measurements were made in Biegnik (silver fir), Ropica Polska (silver birch, black locust) and Szymbark (silver birch, European beech, European hornbeam, silver fir, sycamore maple, Scots pine, European spruce) located near Gorlice (The Low Beskids) in areas with unplanned forest management. In case of each tested tree species the samples of roots were taken, transported to the laboratory and then saturated with water for at least one day. Before testing the samples were obtained from the water and stretched in a. tensile testing machine in order to determine their tensile strength and flexibility. In general, over 2200 root samples were tested. The results of tests on root area ratio of root systems and their tensile strength were used to determine the value of increase in shear strength of the soils, called root cohesion. To this purpose a classic Wu-Waldron calculation model was used as well as two types of bundle models, the so called static model (Fiber Bundle Model — FIRM, FBM2, FBM3) and the deformation model (Root Bundle Model— RBM1, RBM2, mRBM1) that differ in terms of the assumptions concerning the way the tensile force is distributed to the roots as well as the range of parameters taken into account during calculations. The stability analysis of 8 landslides in forest areas of Cicikowicleie and Wignickie Foothills was a form of verification of relevance of the obtained calculation results. The results of tests on root area ratio in the profile showed that, as expected, the number of roots in the soil profile and their ApIA values are very variable. It was shown that the values of the root area ratio of the tested tree species with a diameter 1-10 ram are a maximum of 0.8% close to the surface of the ground and they decrease along with the depth reaching the values at least one order of magnitude lower than close to the surface at the depth 0.5-1.0 m below the ground level. Average values of the root area ratio within the soil profile were from 0.05 to 0.13% adequately for Scots pine and European beech. The measured values of the root area ratio are relatively low in relation to the values of this parameter given in literature, which is probably connected with great cohesiveness of the soils and the fact that there were a lot of rock fragments in the soil, where the tests were carried out. Calculation results of the Gale-Grigal function indicate that a distribution of roots in the soil profile is similar for the tested species, apart from the silver fir from Bie§nik and European hornbeam. Considering the number of roots, their distribution in the soil profile and the root area ratio it appears that — considering slope stability — the root systems of European beech and black locust are the most optimal, which coincides with tests results given in literature. The results of tensile strength tests showed that the roots of the tested tree species have different tensile strength. The roots of European beech and European hornbeam had high tensile strength, whereas the roots of conifers and silver birch in deciduous trees — low. The analysis of test results also showed that the roots of the studied tree species are characterized by high variability of mechanical properties. The values Of shear strength increase are mainly related to the number and size (diameter) of the roots in the soil profile as well as their tensile strength and pullout resistance, although they can also result from the used calculation method (calculation model). The tests showed that the distribution of roots in the soil and their tensile strength are characterized by large variability, which allows the conclusion that using typical geotechnical calculations, which take into consideration the role of root systems is exposed to a high risk of overestimating their influence on the soil reinforcement. hence, while determining or assuming the increase in shear strength of soil reinforced with roots (root cohesion) for design calculations, a conservative (careful) approach that includes the most unfavourable values of this parameter should be used. Tests showed that the values of shear strength increase of the soil reinforced with roots calculated using Wu-Waldron model in extreme cases are three times higher than the values calculated using bundle models. In general, the most conservative calculation results of the shear strength increase were obtained using deformation bundle models: RBM2 (RBMw) or mRBM1. RBM2 model considers the variability of strength characteristics of soils described by Weibull survival function and in most cases gives the lowest values of the shear strength increase, which usually constitute 50% of the values of shear strength increase determined using classic Wu-Waldron model. Whereas the second model (mRBM1.) considers averaged values of roots strength parameters as well as the possibility that two main mechanism of destruction of a root bundle - rupture and pulling out - can occur at the same. time. The values of shear strength increase calculated using this model were the lowest in case of beech and hornbeam roots, which had high tensile strength. It indicates that in the surface part of the profile (down to 0.2 m below the ground level), primarily in case of deciduous trees, the main mechanism of failure of the root bundle will be pulling out. However, this model requires the knowledge of a much greater number of geometrical parameters of roots and geotechnical parameters of soil, and additionally it is very sensitive to input data. Therefore, it seems practical to use the RBM2 model to assess the influence of roots on the soil shear strength increase, and in order to obtain safe results of calculations in the surface part of the profile, the Weibull shape coefficient equal to 1.0 can be assumed. On the other hand, the Wu-Waldron model can be used for the initial assessment of the shear strength increase of soil reinforced with roots in the situation, where the deformation properties of the root system and its interaction with the soil are not considered, although the values of the shear strength increase calculated using this model should be corrected and reduced by half. Test results indicate that in terms of slope stability the root systems of beech and hornbeam have the most favourable properties - their maximum effect of soil reinforcement in the profile to the depth of 0.5 m does not usually exceed 30 kPa, and to the depth of 1 m - 20 kPa. The root systems of conifers have the least impact on the slope reinforcement, usually increasing the soil shear strength by less than 5 kPa. These values coincide to a large extent with the range of shear strength increase obtained from the direct shear test as well as results of stability analysis given in literature and carried out as part of this work. The analysis of the literature indicates that the methods of measuring tree's root systems as well as their interpretation are very different, which often limits the possibilities of comparing test results. This indicates the need to systematize this type of tests and for this purpose a root distribution model (RDM) can be used, which can be integrated with any deformation bundle model (RBM). A combination of these two calculation models allows the range of soil reinforcement around trees to be determined and this information might be used in practice, while planning bioengineering procedures in areas exposed to surface mass movements. The functionality of this solution can be increased by considering the dynamics of plant develop¬ment in the calculations. This, however, requires conducting this type of research in order to obtain more data.