Proposal of redundant drive wire mechanism for producing motions with high acceleration and high precision

A new wire mechanism called Redundant Drive Wire Mechanism (RDWM) is proposed. The purpose of this paper is to build up the theory of a RDWM with fast motion and fine motion. First, the basic concepts of the proposed mechanism is presented. Second, the vector closure condition for the proposed mechanism is developed. Next, we present the basic equations, propose the basic structure of RDWM with the Internal DOF module, Double Actuation Modules and Precision Modules together with the properties of the mechanism. Finally, we conduct the simulation to show the validity of the RDWM.

Kinematical analysis of redundant drive wire mechanisms with velocity constraint

In this paper, we propose a new velocity constraint type for Redundant Drive Wire Mechanisms. The purpose of this paper is to demonstrate that the proposed velocity constraint module can fix the orientation of the movable part and to use the kinematical analysis method to obtain the moving direction of the movable part. First, we discuss the necessity of using this velocity constraint type and the possible applications of the proposed mechanism. Second, we derive the basic equations of a wire mechanism with this constraint type. Next, we present a method of motion analysis on active and passive constraint spaces, which is used to find the moving direction of a movable part. Finally, we apply the above analysis method on a wire mechanism with a velocity constraint module and on a wire mechanism with four double actuator modules. By evaluating the results, we prove the validity of the proposed constraint type.

Do the legs of magnetic clouds contain twisted flux-rope magnetic fields?

Magnetic clouds (MCs) are a subset of interplanetary coronal mass ejections (ICMEs) characterised primarily by a smooth rotation in the magnetic field direction indicative of the presence of a magnetic flux rope. Energetic particle signatures suggest MC flux ropes remain magnetically connected to the Sun at both ends, leading to widely used model of global MC structure as an extended flux rope, with a loop-like axis stretching out from the Sun into the heliosphere and back to the Sun. The time of flight of energetic particles, however, suggests shorter magnetic field line lengths than such a continuous twisted flux rope would produce. In this study, two simple models are compared with observed flux rope axis orientations of 196 MCs to show that the flux rope structure is confined to the MC leading edge. The magnetic cloud “legs,” which magnetically connect the flux rope to the Sun, are not recognisable as MCs and thus are unlikely to contain twisted flux rope fields. Spacecraft encounters with these non-flux rope legs may provide an explanation for the frequent observation of non-magnetic cloud ICMEs.

Fast long-range connections in transportation networks

Multidimensional scaling is applied in order to visualize an analogue of the small-world effect implied by edges having different displacement velocities in transportation networks. Our findings are illustrated for two real-world systems, namely the London urban network (streets and underground) and the US highway network enhanced by some of the main US airlines routes. We also show that the travel time in these two networks is drastically changed by attacks targeting the edges with large displacement velocities. (C) 2011 Elsevier By. All rights reserved.

On the efficiency of transportation systems in large cities

We report an analysis of the accessibility between different locations in big cities, which is illustrated with respect to London and Paris. The effects of the respective underground systems in facilitating more uniform access to diverse places are also quantified and investigated. It is shown that London and Paris have markedly different patterns of accessibility, as a consequence of the number of bridges and large parks of London, and that in both cases the respective underground systems imply in general, thought in distinct manners, an increase of accessibility. Copyright (C) EPLA, 2010

Electrical Students Learning to Wire a House

In a classroom at the New York Trade School, students in the Electrical program are shown learning to wire a house. Black and white photograph.

Behaviour of Surface Defects in Wire Rod Rolling

Defects are often present in rolled products, such as wire rod. The markets demand for wire rod without any defects has increased. In the final wire rod products, defects originating from the steel making, casting, pre-rolling of billets and during the wire rod rolling can appear. In this work, artificial V-shaped longitudinal surface cracks has been analysed experimentally and by means of FEM. The results indicate that the experiments and FEM calculations show the same tendency except in two cases, where instability due to a fairly “round” false round bars disturbed the experiment. FE studies in combination with practical experiments are necessary in order to understand the behaviour of the material flows in the groove and to explain whether the crack will open up as a V-shape or if it will be closed as an I-shape.

Tribological Testing of Some Potential PVD and CVD Coatings for Steel Wire Drawing Dies

Cemented carbide is today the most frequently used drawing die material in steel wire drawing applications. This is mainly due to the possibility to obtain a broad combination of hardness and toughness thus meeting the requirements concerning strength, crack resistance and wear resistance set by the wire drawing process. However, the increasing cost of cemented carbide in combination with the possibility to increase the wear resistance of steel through the deposition of wear resistant CVD and PVD coatings have enhanced the interest to replace cemented carbide drawing dies with CVD and PVD coated steel wire drawing dies. In the present study, the possibility to replace cemented carbide wire drawing dies with CVD and PVD coated steel drawing dies have been investigated by tribological characterisation, i.e. pin-on-disc and scratch testing, in combination with post-test observations of the tribo surfaces using scanning electron microscopy, energy dispersive X-ray spectroscopy and 3D surface profilometry. Based on the results obtained, CVD and PVD coatings aimed to provide improved tribological performance of steel wire drawing dies should display a smooth surface topography, a high wear resistance, a high fracture toughness (i.e. a high cracking and chipping resistance) and intrinsic low friction properties in contact with the wire material. Also, the steel substrate used must display a sufficient load carrying capacity and resistance to thermal softening. Of the CVD and PVD coatings evaluated in the tribological tests, a CVD TiC and a PVD CrC/C coating displayed the most promising results.

Transportation in Maine

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DRAFT PROPOSED PUBLIC TRANSPORTATION ROUTES FOR WATERVILLE, ME

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Draft Proposed Public Transportation Routes for Waterville, ME

Currently, there is a public bus transportation route in Waterville, Maine. However, this system could be improved. Our goal was to use GIS to find optimal public transportation routes throughout the city based on given points of interest and high population density areas. Three different groups of points of interest were created in the North, West, and South sections of Waterville. Using the Network Analyst tool, which calculates optimal routes, using existing street data, based on the input of stops, barriers, and impedance, we ran an analysis of what we thought would be the routes that best served the greatest number of people. Two different sets of routes were found: one with length as the impedance (the shortest length between the selected stops was favored), and one with population density as the impedance (the roads with the highest population density were favored). Finally, the times of the resulting routes (given a constant speed limit of 25 mph) were calculated and evaluated.

Future cenario planning in Brazilian logistics and transportation sector

Nas últimas décadas o setor de logística passou por grandes transformações pelo mundo. Assim, a eficiência do sistema logístico é importante para o crescimento econômico, a diversificação, redução dos custos operacionais e da pobreza. Segundo o Banco Mundial, o Brasil tornou-se uma das maiores economias do mundo, mas os custos logísticos elevados colocam em risco esse crescimento. Estes custos são em grande parte o resultado de diferenças em infraestrutura de cada região, juntamente com os encargos do setor rodoviário, que corresponde por 60% do total do transporte de carga do país. Entretanto, a logística brasileira está às portas de uma nova revolução, em práticas de negócios e eficiência, e também na qualidade e disponibilidade da infraestrutura de transportes e comunicações, e novos projetos e práticas para superar a situação. O objetivo deste estudo não é analisar o presente e as atuais tendências de logística do Brasil e do setor de transporte, mas sim modelar possíveis cenários futuros para os próximos anos. Em outras palavras, este trabalho mostra diferentes possibilidades de como o setor de logística e transporte poderá ser no futuro. Para isso, este trabalho irá utilizar a metodologia de cenários prospectivos e entrevistas com especialistas relacionados da área.

“The Wire”: O que a série de TV diz sobre os #baltimoreriots

Não é raro que o universo da ficção se misture com a realidade nas redes sociais – sobretudo quando a ficção ajuda a entender e explicar acontecimentos da política ou da economia, por exemplo. Foi o que ocorreu esta semana nos Estados Unidos, em virtude da mobilização popular em Baltimore em protestos pela morte do jovem negro Freddie Gray sob custódia da polícia em 19 de abril. A prestigiada série de TV americana “The Wire”, produzida pela HBO de 2002 a 2008 e que aborda diversos prismas sociopolíticos de Baltimore, vem sendo lembrada com frequência no contexto dos protestos.

Oral and maxillofacial reconstruction in a cat using wire and acrylic

A 15-month-old DSH cat was presented with facial deformity secondary to multiple oral and maxillofacial fractures after being struck by an automobile. Multiple wires and dental acrylics were used for fracture repair.