769 resultados para endless rolling
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In recent years, there has been an enormous growth of location-aware devices, such as GPS embedded cell phones, mobile sensors and radio-frequency identification tags. The age of combining sensing, processing and communication in one device, gives rise to a vast number of applications leading to endless possibilities and a realization of mobile Wireless Sensor Network (mWSN) applications. As computing, sensing and communication become more ubiquitous, trajectory privacy becomes a critical piece of information and an important factor for commercial success. While on the move, sensor nodes continuously transmit data streams of sensed values and spatiotemporal information, known as ``trajectory information". If adversaries can intercept this information, they can monitor the trajectory path and capture the location of the source node. ^ This research stems from the recognition that the wide applicability of mWSNs will remain elusive unless a trajectory privacy preservation mechanism is developed. The outcome seeks to lay a firm foundation in the field of trajectory privacy preservation in mWSNs against external and internal trajectory privacy attacks. First, to prevent external attacks, we particularly investigated a context-based trajectory privacy-aware routing protocol to prevent the eavesdropping attack. Traditional shortest-path oriented routing algorithms give adversaries the possibility to locate the target node in a certain area. We designed the novel privacy-aware routing phase and utilized the trajectory dissimilarity between mobile nodes to mislead adversaries about the location where the message started its journey. Second, to detect internal attacks, we developed a software-based attestation solution to detect compromised nodes. We created the dynamic attestation node chain among neighboring nodes to examine the memory checksum of suspicious nodes. The computation time for memory traversal had been improved compared to the previous work. Finally, we revisited the trust issue in trajectory privacy preservation mechanism designs. We used Bayesian game theory to model and analyze cooperative, selfish and malicious nodes' behaviors in trajectory privacy preservation activities.^
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Although he did not write copious novels, endless essays, or long poems, Jorge Luis Borges is considered one of today's best modem writers. His works have never been more than ten pages long. The purpose of this dissertation is to demonstrate that the willing use of concise expression in Borges's writings is inscribed in a poetic worldview of great implications. This view is based on the synthesis of philosophical, literary, and cultural issues that Borges interprets, discusses, refutes, and re-elaborates with a new conjectural approach. This dissertation is based on a methodological review of all his current scholarly work and on a thorough examination of the four volumes of his Complete Works, edited by Emece, in 2002. His pantheistic vision, the epiphanic moments, and his love/hate relationship with language, conform an aesthetic of resounding silence that enlightens the hidden aspects of his brief masterpieces. Even though Borgesian studies flood the library he once imagined, they have been presented in an isolated manner. This dissertation establishes a link among the various aforementioned aspects as studied by Borges scholars, and demonstrates the powerful influence of Borges's illuminating and precise vision. Paradoxically, the poetry of brevity in Borges's works is filled with allusions to the things that Borges silences, because, from a panoramic pantheism, his words almost reach an epiphanic enlightenment that flashes between preterit and future nothingness. By replacing extension with intensity, and mastering the art of omission, Borges's laborious work reaches power and concentration that only the very greatest talents can achieve. His delicate verbal conciseness provides his readers with a virtually infinite freedom of imagination because it exposes them to the chaotic world of mythical probabilities, where an instant encompasses etemity.
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In 1974, the Geological Survey of Japan began its systematic investigation of manganese nodules in the Central Pacific Basin on the new geological research vessel Hakurei Maru. The first cruise (GH 74-5) was carried out over an eastern part area of the Basin (6°-10°30'N, 164°30'-171°30'W), and the authors report here the preliminary results on the occurrence of manganese nodule deposits, paying particular consideration to their relationship to submarine topography and surficial and sub-bottom sedimentary facies. The surveyed area comprises a deep-sea basin at 5,000-5,400 m, defined to the north and east by the chain of seamounts and guyots of the Christmas Ridge. The deep-sea basin is divided roughly into 2 contrasting topographic features. The eastern part is characterised by flattened topography resulting from continuous deposition of turbidities; the meridian and western parts are characterised by gently rolling topography and the existence of a large number of deep-sea hills. Manganese nodules are almost lacking in the former flattened eastern area, whereas they are widely distributed in the latter rolling meridian and western parts. The population density of nodules varies from less than 1 Kg/m² to 26 kg/m² and the higher density is found in the siliceous-calcareous ooze zone of rather small, flat basins surrounded by deep-sea hills. The density is closely related to the thickness of the transparent layer obtained by 3.5 kHz PDR profiling over the whole area. Considering the various data of grab sampling, 3.5 kHz PDR profiling and to a lesser extent of deep-sea television and camera observations, the most promising manganese field in the present area seems to be confined to the north of the western sector of the area.
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The micro-deformations caused by cyclic loading origins the variation of the distances between atoms of the crystal lattice producing the irreversible component. In order to study and understand the microstructural behavior of the material this paper investigated the influence suffered by residual stresses in thrust rolling bearing races fabricated in AISI 52100 steel, after tests by cyclic rolling contact in a tribometer at 1m/s under two contact pressures (500 MPa and 1400 MPa) in dry and boundary lubrication conditions. Procedures of tests thermo-acustically isolated were developed for monitoring the contact temperature and sound pressure level signals to establish a comparison between the residual stress measurements, micro-hardness Vickers and micrographic registers searching an indication of wear evolution. The sin²ψ method by X-ray diffraction technique was used to quantify the residual stresses. Three raceway zones were selected for the evaluation of wear and surface morphology after predetermined cycling, comparing with their new condition ("as received"). Micro-hardness and residual stress measurements showed significant changes after the tests and it was possible to observe the relationship between the increase of sound pressure level and the residual stress for dry and lubricated conditions.
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The micro-deformations caused by cyclic loading origins the variation of the distances between atoms of the crystal lattice producing the irreversible component. In order to study and understand the microstructural behavior of the material this paper investigated the influence suffered by residual stresses in thrust rolling bearing races fabricated in AISI 52100 steel, after tests by cyclic rolling contact in a tribometer at 1m/s under two contact pressures (500 MPa and 1400 MPa) in dry and boundary lubrication conditions. Procedures of tests thermo-acustically isolated were developed for monitoring the contact temperature and sound pressure level signals to establish a comparison between the residual stress measurements, micro-hardness Vickers and micrographic registers searching an indication of wear evolution. The sin²ψ method by X-ray diffraction technique was used to quantify the residual stresses. Three raceway zones were selected for the evaluation of wear and surface morphology after predetermined cycling, comparing with their new condition ("as received"). Micro-hardness and residual stress measurements showed significant changes after the tests and it was possible to observe the relationship between the increase of sound pressure level and the residual stress for dry and lubricated conditions.
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The present work analyzed the tribological behavior of coatings/surface modifications traditionally used in cold rolling mill rolls and new coatings/surface modificationswith potential to replace the carcinogenic hard chrome. The study started with identification of wear mechanisms occurring in real coldrollingmill rolls. Due the high cost and dimensions of the rolls, thereplication technique was used. Replicas were obtained from 4 different rolling millBrazilian companies before and after a normal rolling campaign. Initial sliding tests were conducted using spherical and cylindrical counter bodies in order to verifywhichtribological conditions allowed to reproduce the wear mechanisms found in the replicas. These tests indicated the use of reciprocating sliding tests with cylindrical counter bodies (line contact), normal load of 100 N, and test times of and 1 h and 5 h. Different surface modifications were carried out on samples produced from a fragment of a rolling mill roll. The specimens were heat treated and ground on both sides. After, some specimens were surface textured by electrical discharge texturing (EDT). For both groups (ground and EDT), subsequent treatments of chromium plating, electroless NiP coating and plasma nitriding were carried out. The results of the reciprocating tests showed that specimens with electroless NiP coating presented the lowest friction coefficients, while plasma nitrided specimens showed the highest. In general, previous surface texturing before the coating/surface modification increased the wear of the counter bodies. Oneexceptionwas for EDT with subsequent electroless NiP coating, which presented the lowest counter bodies wear rate. The samples withelectroless NiP coating promoted a tribolayer consisting of Nickel, Phosphorus and Oxygen on both the specimens andthecounter bodies, which was apparently responsible for the reduction of friction coefficient and wear rate. The increase of the test time reduced the wear rate of the samples, apparently due the stability of the tribolayers formed, except for the nitrided samples. For the textured specimens, NiP coating showed the best performance in maintaining the surface topography of the specimens after the sliding tests.
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Acknowledgements Many parties contributed to making this paper a reality. This research was supported by the European Social and Research Council, grant ESRC ES/K006428/1. The author is particularly grateful to the grant’s holder, Professor David Anderson from the Department of Anthropology, University of Aberdeen, for his various support throughout this research. The Barents Center of the Humanities at Kola Science Center of the Russian Academy of Sciences in Apatity provided important institutional support. Officials from several fisheries management institutions of Arkhangelsk oblast, including Shiriaev Igor Alekseevich from Dvinsko-Pechorskoe Territorial Management Board, Skovorod’ko Artem Aleksandrovich from the Northern Basin Directorate of Fisheries and Water Biological Resources Conservation (Sevrybvod) and Korotenkov Aleksei Anatol’evich from the Fishing Industry Agency of Arkhangelsk oblast were very supportive and shared their knowledge wherever possible. Scholars Studenov Igor Ivanovich and Stasenkov Vladimir Aleksandrovich at Northern branch of the Knipovich Polar Research Institute of Marine Fisheries and Oceanography (SevPINRO) in Arkhangelsk provided their invaluable expertise on marine fisheries. Chairmen of several fishing collective farms – Tuchin Sergei Viktorovich, Samoilov Sergei Nikolaevich and Seliverstova Marina Nikolaevna – offered a great administrative support. Local residents of several villages in Mezen region were extremely generous and hospitable, providing places to stay, warm clothes, food, endless cups of tea, and most valuably, sparing their time. Finally, Natalie Wahnsiedler was a regular companion during fieldwork and a great source of inspiration for this research.
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Acknowledgements Many parties contributed to making this paper a reality. This research was supported by the European Social and Research Council, grant ESRC ES/K006428/1. The author is particularly grateful to the grant’s holder, Professor David Anderson from the Department of Anthropology, University of Aberdeen, for his various support throughout this research. The Barents Center of the Humanities at Kola Science Center of the Russian Academy of Sciences in Apatity provided important institutional support. Officials from several fisheries management institutions of Arkhangelsk oblast, including Shiriaev Igor Alekseevich from Dvinsko-Pechorskoe Territorial Management Board, Skovorod’ko Artem Aleksandrovich from the Northern Basin Directorate of Fisheries and Water Biological Resources Conservation (Sevrybvod) and Korotenkov Aleksei Anatol’evich from the Fishing Industry Agency of Arkhangelsk oblast were very supportive and shared their knowledge wherever possible. Scholars Studenov Igor Ivanovich and Stasenkov Vladimir Aleksandrovich at Northern branch of the Knipovich Polar Research Institute of Marine Fisheries and Oceanography (SevPINRO) in Arkhangelsk provided their invaluable expertise on marine fisheries. Chairmen of several fishing collective farms – Tuchin Sergei Viktorovich, Samoilov Sergei Nikolaevich and Seliverstova Marina Nikolaevna – offered a great administrative support. Local residents of several villages in Mezen region were extremely generous and hospitable, providing places to stay, warm clothes, food, endless cups of tea, and most valuably, sparing their time. Finally, Natalie Wahnsiedler was a regular companion during fieldwork and a great source of inspiration for this research.
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“Spaces of Order” argues that the African novel should be studied as a revolutionary form characterized by aesthetic innovations that are not comprehensible in terms of the novel’s European archive of forms. It does this by mapping an African spatial order that undermines the spatial problematic at the formal and ideological core of the novel—the split between a private, subjective interior, and an abstract, impersonal outside. The project opens with an examination of spatial fragmentation as figured in the “endless forest” of Amos Tutuola’s The Palmwine Drinkard (1952). The second chapter studies Chinua Achebe’s Things Fall Apart (1958) as a fictional world built around a peculiar category of space, the “evil forest,” which constitutes an African principle of order and modality of power. Chapter three returns to Tutuola via Ben Okri’s The Famished Road (1991) and shows how the dispersal of fragmentary spaces of exclusion and terror within the colonial African city helps us conceive of political imaginaries outside the nation and other forms of liberal political communities. The fourth chapter shows Nnedi Okorafor—in her 2014 science-fiction novel Lagoon—rewriting Things Fall Apart as an alien-encounter narrative in which Africa is center-stage of a planetary, multi-species drama. Spaces of Order is a study of the African novel as a new logic of world making altogether.
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‘Shock’ advertising is the new black and the subject of the reflection in which this article engages. We do this in particular through consideration of the (largely) British high-street fashion house French Connection’s seemingly endless ‘FCUK’ campaign. The obvious resonance between this abbreviation and perhaps the most popular word in the English language was at the heart of the campaign’s appeal and it continues today through various extensions on both slogans and logos on French Connection’s own goods and indeed those who seek to piggy back upon and/or subvert its market power. It is far from the only example of such ‘shock’ tactics. Whether discussing reproduction in graphic detail with children, joyously dismantling chastity, or merely fucking with fuck, it seems that traditional mores can no longer remain virgin territory, unsullied by rapacious marketing. Our mediated experiences of reaching ‘extremes’, it now appears, are not paralysing, mesmerising, fascinating or inspiring but simply a further prod down the path leading to (gleeful) purchase. In this paper we explore how, via a series of semiotic reversals, the new, the strange, the unfamiliar and the would-be shocking are rendered banal, and thus thoroughly comprehensible through brand association and the endless re-iteration of existing works.
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Moving through a stable, three-dimensional world is a hallmark of our motor and perceptual experience. This stability is constantly being challenged by movements of the eyes and head, inducing retinal blur and retino-spatial misalignments for which the brain must compensate. To do so, the brain must account for eye and head kinematics to transform two-dimensional retinal input into the reference frame necessary for movement or perception. The four studies in this thesis used both computational and psychophysical approaches to investigate several aspects of this reference frame transformation. In the first study, we examined the neural mechanism underlying the visuomotor transformation for smooth pursuit using a feedforward neural network model. After training, the model performed the general, three-dimensional transformation using gain modulation. This gave mechanistic significance to gain modulation observed in cortical pursuit areas while also providing several testable hypotheses for future electrophysiological work. In the second study, we asked how anticipatory pursuit, which is driven by memorized signals, accounts for eye and head geometry using a novel head-roll updating paradigm. We showed that the velocity memory driving anticipatory smooth pursuit relies on retinal signals, but is updated for the current head orientation. In the third study, we asked how forcing retinal motion to undergo a reference frame transformation influences perceptual decision making. We found that simply rolling one's head impairs perceptual decision making in a way captured by stochastic reference frame transformations. In the final study, we asked how torsional shifts of the retinal projection occurring with almost every eye movement influence orientation perception across saccades. We found a pre-saccadic, predictive remapping consistent with maintaining a purely retinal (but spatially inaccurate) orientation perception throughout the movement. Together these studies suggest that, despite their spatial inaccuracy, retinal signals play a surprisingly large role in our seamless visual experience. This work therefore represents a significant advance in our understanding of how the brain performs one of its most fundamental functions.
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Few works within the realm of the piano repertoire have amassed a reputation as formidable as Gaspard de la Nuit. These three pieces, each unique in character and pianistic requirements, arguably represent a pinnacle of early 20th-century French piano music. This paper seeks to illuminate points for consideration for the pianist who wishes to embark upon studying the work for performance, and for the musicologist.
I shall first consider the three character poems of Aloysius Bertrand that inspired the suite, as an understanding of these Diabolic creations is essential to understanding the piece analytically and programmatically. I shall then explore the subtitle of Bertrand’s Gaspard de la Nuit: ‘Fantaisies À La Manière De Rembrandt Et De Callot’, as an acknowledgement of these artists helps us better to engage with Bertrand’s poetry, and provides us with a direct link to the visual stimuli for Ravel’s compositions.
Finally, using Ondine as a case study, I shall explore how the composer unifies his inspirations to paint a musical portrait of both the character and the content of Bertrand’s poem. I shall focus on three particular aspects of Ravel’s style: the refined textures that create washes of watery colour, subtle rhythmic variations that imply the ‘deep, rolling currents of the sleeping lake’, and the simple melodic lines sung by the water nymph in the manner of a French air. Each element plays its part in the thematic development that illustrates Ondine’s seductive powers.
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An investigation was carried out on CLT panels made from Sitka spruce in order to establish the effect of the thickness of CLT panels on the bending stiffness and strength and the rolling shear. Bending and shear tests on 3-layer and 5-layer panels were performed with loading in the out-of-plane and in-plane directions. ‘Global’ stiffness measurements were found to correlate well with theoretical values. Based on the results, there was a general tendency that both the bending strength and rolling shear decreased with panel thickness. Mean values for rolling shear ranged from 1.0 N/mm2 to 2.0 N/mm2 .
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Die Masse eines Gegengewichtstaplers beeinflusst den Energieverbrauch beim Fahren maßgeblich. Steigende Energiepreise und steigendes Umweltbewusstsein führen zu grünen Trends in Logistik. Durch Reduktion der Gesamtmasse eines Gabelstaplers können große Einsparungen erreicht werden. Eine Machbarkeitsstudie soll mithilfe der numerischen Simulationen zeigen, dass neuartige Fahrzeuge mit aktiven Systemen trotz geringerer Masse hinreichend hohe Standsicherheit aufweisen können. In diesem Beitrag sollen die ersten Ergebnisse dieses Forschungsvorhabens vorgestellt werden.
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If magnetism is universal in nature, magnetic materials are ubiquitous. A life without magnetism is unthinkable and a day without the influence of a magnetic material is unimaginable. They find innumerable applications in the form of many passive and active devices namely, compass, electric motor, generator, microphone, loud speaker, maglev train, magnetic resonance imaging, data recording and reading, hadron collider etc. The list is endless. Such is the influence of magnetism and magnetic materials in ones day to day life. With the advent of nanoscience and nanotechnology, along with the emergence of new areas/fields such as spintronics, multiferroics and magnetic refrigeration, the importance of magnetism is ever increasing and attracting the attention of researchers worldwide. The search for a fluid which exhibits magnetism has been on for quite some time. However nature has not bestowed us with a magnetic fluid and hence it has been the dream of many researchers to synthesize a magnetic fluid which is thought to revolutionize many applications based on magnetism. The discovery of a magnetic fluid by Jacob Rabinow in the year 1952 paved the way for a new branch of Physics/Engineering which later became magnetic fluids. This gave birth to a new class of material called magnetorheological materials. Magnetorheological materials are considered superior to electrorheological materials in that magnetorheology is a contactless operation and often inexpensive.Most of the studies in the past on magnetorheological materials were based on magnetic fluids. Recently the focus has been on the solid state analogue of magnetic fluids which are called Magnetorheological Elastomers (MREs). The very word magnetorheological elastomer implies that the rheological properties of these materials can be altered by the influence of an external applied magnetic field and this process is reversible. If the application of an external magnetic field modifies the viscosity of a magnetic fluid, the effect of external magnetic stimuli on a magnetorheological elastomer is in the modification of its stiffness. They are reversible too. Magnetorheological materials exhibit variable stiffness and find applications in adaptive structures of aerospace, automotive civil and electrical engineering applications. The major advantage of MRE is that the particles are not able to settle with time and hence there is no need of a vessel to hold it. The possibility of hazardous waste leakage is no more with a solid MRE. Moreover, the particles in a solid MRE will not affect the performance and durability of the equipment. Usually MR solids work only in the pre yield region while MR fluids, typically work in the post yield state. The application of an external magnetic field modifies the stiffness constant, shear modulus and loss modulus which are complex quantities. In viscoelastic materials a part of the input energy is stored and released during each cycle and a part is dissipated as heat. The storage modulus G′ represents the capacity of the material to store energy of deformation, which contribute to material stiffness. The loss modulusG′′ represents the ability of the material to dissipate the energy of deformation. Such materials can find applications in the form of adaptive vibration absorbers (ATVAs), stiffness tunable mounts and variable impedance surfaces. MREs are an important material for automobile giants and became the focus of this research for eventual automatic vibration control, sound isolation, brakes, clutches and suspension systems