On the domain decomposition and transmission line modelling finite element method for time-domain induction motor analysis

This paper demonstrates how a finite element model which exploits domain decomposition is applied to the analysis of three-phase induction motors. It is shown that a significant gain in cpu time results when compared with standard finite element analysis. Aspects of the application of the method which are particular to induction motors are considered: the means of improving the convergence of the nonlinear finite element equations; the choice of symmetrical sub-domains; the modelling of relative movement; and the inclusion of periodic boundary conditions. © 1999 IEEE.

Performance and reliability of flexible substrates when subjected to lead-free processing

The use of flexible substrates is growing in many applications such as computer peripherals, hand held devices, telecommunications, automotive, aerospace, etc. The drive to adopt flexible circuits is due to their ability to reduce size, weight, assembly time and cost of the final product.They also accommodate flexibility by allowing relative movement between component parts and provide a route for three dimensional packaging. This paper will describe some of the current research results from the Flex-No-Lead project, a European Commission sponsored research program. The principle aim of this project is to investigate the processing, performance, and reliability of flexible substrates when subjected to new environmentally friendly, lead-free soldering technologies. This paper will discuss the impact of specific design variables on performance and reliability. In particular the paper will focus on copper track designs, substrate material, dielectric material and solder-mask defined joints.

Modelling the reliability of components on flexible substrates

The use of flexible substrates is growing in many applications such as computer peripherals, hand held devices, telecommunications, automotive, aerospace, etc. The drive to adopt flexible circuits is due to their ability to reduce size, weight, assembly time and cost of final product. they also accommodate flexibility by allowing relative movement between component parts and provide a route for three dimensional packaging. This paper will describe some of the current research results from the Flex-No-Lead project, European Commission sponsored programme. The principle aim of this project is to investigate the processing, performance and reliability of flexible substrates when subjected to new environmentally friendly, lead-free soldering technologies. This paper will discuss the impact of specific design variables on performance and reliability. In particular the paper will focus on copper track designs, substrate material, dielectric material and solder mask defined joints

Developments in retrodirective array technology

There has been significant interest in retrodirective antennas, especially considering the wealth of applications that could be significantly enhanced, or created, by the use of such technology. There is enormous potential for retrodirective antennas where complicated automatic tracking systems would benefit from being replaced by much simpler systems. Retrodirective array technology offers one solution pathway since it can offer extremely fast tracking with relatively simple circuitry. Retrodirective or self-steering arrays are suited for low radio frequency (RF) power mobile terminal use particularly on or between un-stabilised vehicles. In this type of operational scenario, high degrees of relative movement are expected, and power consumption and weight of the antenna must be kept to a minimum. In this study, the authors give a brief historical review of basic retrodirective technology and elaborate on some recent developments at Queens University of Belfast associated with retrodirective antenna technology in relation to, two-way communications, ultrafast RADAR, microwave imaging, spatial power transmission, mitigation of multipath effects and spatial encryption.

Optimisation of viscoelastic treatments using genetic algorithms

Viscoelastic treatments are one of the most efficient treatments, as far as passive damping is concerned, particularly in the case of thin and light structures. In this type of treatment, part of the strain energy generated in the viscoelastic material is dissipated to the surroundings, in the form of heat. A layer of viscoelastic material is applied to a structure in an unconstrained or constrained configuration, the latter proving to be the most efficient arrangement. This is due to the fact that the relative movement of both the host and constraining layers cause the viscoelastic material to be subjected to a relatively high strain energy. There are studies, however, that claim that the partial application of the viscoelastic material is just as efficient, in terms of economic costs or any other form of treatment application costs. The application of patches of material in specific and selected areas of the structure, thus minimising the extension of damping material, results in an equally efficient treatment. Since the damping mechanism of a viscoelastic material is based on the dissipation of part of the strain energy, the efficiency of the partial treatment can be correlated to the modal strain energy of the structure. Even though the results obtained with this approach in various studies are considered very satisfactory, an optimisation procedure is deemed necessary. In order to obtain optimum solutions, however, time consuming numerical simulations are required. The optimisation process to use the minimum amount of viscoelastic material is based on an evolutionary geometry re-design and calculation of the modal damping, making this procedure computationally costly. To avert this disadvantage, this study uses adaptive layerwise finite elements and applies Genetic Algorithms in the optimisation process.

Fatigue life assessment of endodontic instruments subjected to multi planar curvature

This present study aimed to investigate the fatigue life of unused (new) endodontic instruments made of NiTi with control memory by Coltene™ and subjected to the multi curvature of a mandibular first molar root canal. Additionally, the instrument‟s structural behaviour was analysed through non-linear finite element analysis (FEA). The fatigue life of twelve Hyflex™ CM files was assessed while were forced to adopt a stance with multiple radius of curvature, similar to the ones usually found in a mandibular first molar root canal; nine of them were subjected to Pecking motion, a relative movement of axial type. To achieve this, it was designed an experimental setup with the aim of timing the instruments until fracture while worked inside a stainless steel mandibular first molar model with relative axial motion to simulate the pecking motion. Additionally, the model‟s root canal multi-curvature was confirmed by radiography. The non-linear finite element analysis was conducted using the computer aided design software package SolidWorks™ Simulation, in order to define the imposed displacement required by the FEA, it was necessary to model an endodontic instrument with simplified geometry using SolidWorks™ and subsequently analyse the geometry of the root canal CAD model. The experimental results shown that the instruments subjected to pecking motion displayed higher fatigue life values and higher lengths of fractured tips than those with only rotational relative movement. The finite element non-linear analyses shown, for identical conditions, maximum values for the first principal stress lower than the yield strength of the material and those were located in similar positions to the instrument‟s fracture location determined by the experimental testing results.

Ion clustering in molecular dynamics simulations of sodium iodide solutions

Model systems of sodium iodide dissolved in dimethyl ether or 1,2-dimethoxyethane (glyme) were studied in order to investigate the structural and dynamic properties of ionic solutions in small and polymeric ethers. Full molecular dynamics simulations were performed at a range of different salt concentrations. An algorithm was designed which assigns ions to clusters and then calculates all the terms which contribute to ionic conductivity. In dilute solutions, free ions are the most common ionic species, followed by ion pairs. As the concentration increases, pairs become the most common species, with significant concentrations of clusters with 3 through 6 ions. Changing the solvent from dimethyl ether to glyme significantly decreases the ion clustering due to the chelate effect in which the two oxygens on a solvent stabilize an associated cation. The conductivity in stable systems is shown to be primarily the result of the movement of free ions and the relative movement of ions within neutral pairs. The Nernst-Einstein relation, commonly used in the discussion of polymer electrolytes, is shown to be inadequate to quantitatively describe conductivity in the model systems.

Circle: orbital commutation

In exercising vision we employ strategies to perceive space and to distinguish the objects of attention. Some processes however remain invisible to us; how we process binocular vision; and how we resolve vision in motion. This work images invisible motion perspective. Revelation of invisible mechanisms of vision exposes the haptic qualities of sight and their contribution to proprioception and ʻaffordanceʼ. Figuring the ʻvortex of visionʼ also releases symbolic and metaphoric potentials. This innovative outcome of practical research develops imagery which depicts relative movement in space using the principles of motion perspective (Herschel) and optic flow (J. J. Gibson); the locative awareness of volumes in space through the dimensions of time and space presented in 2D imagery. The mural scale (3.5 metres) work presented in 'Circle', a group show of work around the idea of 'the circle' curated by Melinda Capp is derived from a large production of digital photographs made in the London Underground. In this work, the circle is associated with the orbit of the commuter which bends around the twin poles of home and employment, work and rest, circulating in an ellipse around the Ideal Life. Each traveller's path is a braid woven through gyrations of force and resistance. Optic flow, emulated with the rotating lens, tracing the moving subject, makes this visible.

Im/mobile

Im/mobile develops imagery of train passengers photographed using a technique that 'dissolves' the vehicle and reveals the temporary human interactions in the state of transit. It is site-specific in the context of White Street Projects which is in the Frankston Station precinct. In terms of public Melbourne commuter transport particularly for the Metro passengers on the Frankston line. It is a window into the demographic and the social relations of suburban Frankston.

Influência da deformação do encosto e do alojamento no campo de tensões em bronzinas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo experimental da indução magnética

This work will discuss how magnetic fields can be produced, either generated by magnets, natural, artificial, or even by an electric current going through a wire, as discovered by Oersted. Besides the theoretical content, experimental studies on magnetic induction and on the Laws of Faraday and Lenz will be performed. In the Magnetic Induction experiment, the electromotive force generated by varying the flow of the field B in a solenoid, depending on the variation of the current intensity and frequency associated with it will be measured; the experiment on the Laws of Faraday and Lenz the electromotive force produced by the relative movement of the magnet in relation to a coil. Thus, this study experimental verification of magnetic induction using solenoids and magnets; analysis of magnetic induction by Faraday's Law and Lenz's Law

Controle de fotoassociação caótica com campos externos

The objective of the present work was to study the control of the dynamics of diatomic heteronuclear molecules interacting with electric fields created by lasers. Specifically in this work, the molecular photoassociation phenomenon will be analyzed. At this phenomenon, the atom's relative movement is described by a particle that moves in a morse potential well under the influence of an external time dependant force related to the external field. Based on the optimum control theory (OCT), it is presented at the present work laser pulses that alternate a given initial molecular state to a desirable end state, wich in this work was represented by the minimization of a cost functional that indicates how close. To do so, a computational sistem know as Genetic Algorithm (GA) was developed that can be characterizes as an extremelly eficient technique capable of scanning the solutions space and find results close to the optimum solutions

Experimental Study on Friction between Saline Ice and Steel

Understanding the interaction of sea ice with offshore structures is of primary importance for the development of technology in cold climate regions. The rheological properties of sea ice (strength, creep, viscosity) as well as the roughness of the contact surface are the main factors influencing the type of interaction with a structure. A device was developed and designed and small scale laboratory experiments were carried out to study sea ice frictional interaction with steel material by means of a uniaxial compression rig. Sea-ice was artificially grown between a stainless steel piston (of circular cross section) and a hollow cylinder of the same material, coaxial to the former and of the same surface roughness. Three different values for the roughness were tested: 1.2, 10 and 30 μm Ry (maximum asperities height), chosen as representative values for typical surface conditions, from smooth to normally corroded steel. Creep tests (0.2, 0.3, 0.4 and 0.6 kN) were conducted at T = -10 ºC. By pushing the piston head towards the cylinder base, three different types of relative movement were observed: 1) the piston slid through the ice, 2) the piston slid through the ice and the ice slid on the surface of the outer cylinder, 3) the ice slid only on the cylinder surface. A cyclic stick-slip motion of the piston was detected with a representative frequency of 0.1 Hz. The ratio of the mean rate of axial displacement to the frequency of the stick-slip oscillations was found to be comparable to the roughness length (Sm). The roughness is the most influential parameter affecting the amplitude of the oscillations, while the load has a relevant influence on the their frequency. Guidelines for further investigations were recommended. Marco Nanetti - seloselo@virgilio.it

Geological and Structural evolution of the Eurasia Africa plate boundary in the Gulf of Cadiz Central Eastern Atlantic Sea.

Iberia Africa plate boundary, cross, roughly W-E, connecting the eastern Atlantic Ocean from Azores triple junction to the Continental margin of Morocco. Relative movement between the two plate change along the boundary, from transtensive near the Azores archipelago, through trascurrent movement in the middle at the Gloria Fracture Zone, to transpressive in the Gulf of Cadiz area. This study presents the results of geophysical and geological analysis on the plate boundary area offshore Gibraltar. The main topic is to clarify the geodynamic evolution of this area from Oligocene to Quaternary. Recent studies have shown that the new plate boundary is represented by a 600 km long set of aligned, dextral trascurrent faults (the SWIM lineaments) connecting the Gloria fault to the Riff orogene. The western termination of these lineaments crosscuts the Gibraltar accretionary prism and seems to reach the Moroccan continental shelf. In the past two years newly acquired bathymetric data collected in the Moroccan offshore permit to enlighten the present position of the eastern portion of the plate boundary, previously thought to be a diffuse plate boundary. The plate boundary evolution, from the onset of compression in the Oligocene to the Late Pliocene activation of trascurrent structures, is not yet well constrained. The review of available seismics lines, gravity and bathymetric data, together with the analysis of new acquired bathymetric and high resolution seismic data offshore Morocco, allows to understand how the deformation acted at lithospheric scale under the compressive regime. Lithospheric folding in the area is suggested, and a new conceptual model is proposed for the propagation of the deformation acting in the brittle crust during this process. Our results show that lithospheric folding, both in oceanic and thinned continental crust, produced large wavelength synclines bounded by short wavelength, top thrust, anticlines. Two of these anticlines are located in the Gulf of Cadiz, and are represented by the Gorringe Ridge and Coral Patch seamounts. Lithospheric folding probably interacted with the Monchique – Madeira hotspot during the 72 Ma to Recent, NNE – SSW transit. Plume related volcanism is for the first time described on top of the Coral Patch seamount, where nine volcanoes are found by means of bathymetric data. 40Ar-39Ar age of 31.4±1.98 Ma are measured from one rock sample of one of these volcanoes. Analysis on biogenic samples show how the Coral Patch act as a starved offshore seamount since the Chattian. We proposed that compression stress formed lithospheric scale structures playing as a reserved lane for the upwelling of mantle material during the hotspot transit. The interaction between lithospheric folding and the hotspot emplacement can be also responsible for the irregularly spacing, and anomalous alignments, of individual islands and seamounts belonging to the Monchique - Madeira hotspot.

Igneous geochemistry of OP Leg 126 samples

Major element, trace element, and radiogenic isotope compositions of samples collected from Ocean Drilling Program Leg 126 in the Izu-Bonin forearc basin are presented. Lavas from the center of the basin (Site 793) are high-MgO, low-Ti, two-pyroxene basaltic andesites, and represent the products of synrift volcanism in the forearc region. These synrift lavas share many of the geochemical and petrographic characteristics of boninites. In terms of their element abundances, ratios, and isotope systematics they are intermediate between low-Ti arc tholeiites from the active arc and boninites of the outer-arc high. These features suggest a systematic geochemical gradation between volcanics related to trench distance and a variably depleted source. A basement high drilled on the western flank of the basin (Site 792) comprises a series of plagioclase-rich two-pyroxene andesites with calc-alkaline affinities. These lavas are similar to calc-alkaline volcanics from Japan, but have lower contents of Ti, Zr, and low-field-strength elements (LFSE). Lavas from Site 793 show inter-element variations between Zr, Ti, Sr, Ni, and Cr that are consistent with those predicted during crystallization and melting processes. In comparison, concentrations of P, Y, LFSE, and the rare-earth elements (REE) are anomalous. These elements have been redistributed within the lava pile, concentrating particularly in sections of massive and pillowed flows. Relative movement of these two-element groupings can be related to the alteration of interstitial basaltic andesite glass to a clay mineral assemblage by a post-eruptive process. Fluid-rock interaction has produced similar effects in the basement lavas of Site 792. In this sequence, andesites and dacites have undergone a volume change related to silica mobility. As a result of this process, some lithologies have the major element characteristics of basaltic andesite and rhyolite, but can be related to andesitic or dacitic precursors by silica removal or addition.