A simple method to predict elastic settlements in foundations resting on two soils of differing deformability

This paper shows the analysis results obtained from more than 200 finite element method (FEM) models used to calculate the settlement of a foundation resting on two soils of differing deformability. The analysis considers such different parameters as the foundation geometry, the percentage of each soil in contact with the foundation base and the ratio of the soils’ elastic moduli. From the described analysis, it is concluded that the maximum settlement of the foundation, calculated by assuming that the foundation is completely resting on the most deformable soil, can be correlated with the settlement calculated by FEM models through a correction coefficient named “settlement reduction factor” (α). As a consequence, a novel expression is proposed for calculating the real settlement of a foundation resting on two soils of different deformability with maximum errors lower than 1.57%, as demonstrated by the statistical analysis carried out. A guide for the application of the proposed simple method is also explained in the paper. Finally, the proposed methodology has been validated using settlement data from an instrumented foundation, indicating that this is a simple, reliable and quick method which allows the computation of the maximum elastic settlement of a raft foundation, evaluates its suitability and optimises its selection process.

DESIGN OF A MINIATURIZED SOP INTEGRATED GNSS RF FRONT-END MODULE

Navigation devices used to be bulky and expensive and were not widely commercialized for personal use. Nowadays, all useful electronic devices are turning into being handheld so that they can be conveniently used anytime and anywhere. One can claim that almost any mobile phone, used today, has quite strong navigational capabilities that can efficiently work anywhere in the globe. No matter where you are, you can easily know your exact location and make your way smoothly to wherever you would like to go. This couldn’t have been made possible without the existence of efficient and small microwave circuits responsible for the transmission and reception of high quality navigation signals. This thesis is mainly concerned with the design of novel highly miniaturized and efficient filtering components working in the Global Navigational Satellite Systems (GNSS) frequency band to be integrated within an efficient Radio Frequency (RF) front-end module (FEM). A System-on-Package (SoP) integration technique is adopted for the design of all the components in this thesis. Two novel miniaturized filters are designed, where one of them is a wideband filter targeting the complete GNSS band with a fractional bandwidth of almost 50% at a center frequency of 1.385 GHz. This filter utilizes a direct inductive coupling topology to achieve the required wide band performance. It also has very good out-of-band rejection and low IL. Whereas the other dual band filter will only cover the lower and upper GNSS bands with a rejection notch in between the two bands. It has very good inter band rejection. The well-known “divide and conquer” design methodology was applied for the design of this filter to help save valuable design and optimization time. Moreover, the performance of two commercially available ultra-Low Noise Amplifiers (LNAs) is studied. The complete RF FEM showed promising preliminary performance in terms of noise figure, gain and bandwidth, where it out performed other commercial front-ends in these three aspects. All the designed circuits are fabricated and tested. The measured results are found to be in good agreements with the simulations.

P. Ovidius Naso /

v.1. Amores. Epistulae. Medic. Fac. Fem. Ars amat. Remedia amoris. 1907. -- v.. Metamorphoses. 1905. -- v.3. Tristia. Ibis. Ex ponto libri. Fasti. 1908.

Medierad narkotikahandel på internets skuggsida : En fallstudie kring svenska säljares erfarenheter

I studien undersöks huruvida en grupp narkotikasäljare på den svenska hemsidan Flugsvamp drivs av andra motivationer än ett grundläggande vinstintresse. Sidan bygger på de teknologiska verktyg som utvecklades av den libertarianskt inspirerade Cypherpunkrörelsens arbete med stark kryptografi i slutet av 1990-talet. Dessa verktyg skyddar både brottslingar och frihetskämpar, men har främst associerats med de som använder anonymiteten i kriminella syften och således har verktygen fått ett dåligt rykte som riskerar äventyra kryptografins framtid. Genom semistrukturerade onlineintervjuer med fem säljare av skiftande karaktär samlade jag information gällande deras upplevelse av sidan, relationerna till kunder och administratörer, hur de rent moraliskt rationaliserade sin verksamhet och vilken påverkan de såg sig ha på samhället och kryptografin. En bild framträdde där majoriteten av säljarna uppvisade ansvarskänsla och eftertänksamhet genom att agera med transparens och professionalitet. Genom att utkonkurrera oärliga aktörer och med ett nära kollegialt samarbete med varandra använde dessa säljare sin roll för att utmana den traditionella majoritetsinställningen till narkotika och visa hur den ansvarsfulla digitala försäljningen i längden kan vara samhällsförändrande. En minoritet uppgav att de endast använde sidan för att tjäna extrapengar och egentligen tyckte att det var en rimlig idé för staten att förbjuda de kryptoanarkistiska verktygen då de främst anses användas i kriminella syften. Studien når fram till slutsatserna att samhället som helhet tjänar på att det narkotikarelaterade våldet försvinner från gatorna, visar på hur en inkonsekvent och konservativ lagstiftning gör sig mottaglig för starka motargument samt understryker att den framtida digitala mänskligheten kommer ha en betydande användning för de kryptoanarkistiska verktygen.

Analysis of transient eddy currents in MRI using a cylindrical FDTD method

Most magnetic resonance imaging (MRI) spatial encoding techniques employ low-frequency pulsed magnetic field gradients that undesirably induce multiexponentially decaying eddy currents in nearby conducting structures of the MRI system. The eddy currents degrade the switching performance of the gradient system, distort the MRI image, and introduce thermal loads in the cryostat vessel and superconducting MRI components. Heating of superconducting magnets due to induced eddy currents is particularly problematic as it offsets the superconducting operating point, which can cause a system quench. A numerical characterization of transient eddy current effects is vital for their compensation/control and further advancement of the MRI technology as a whole. However, transient eddy current calculations are particularly computationally intensive. In large-scale problems, such as gradient switching in MRI, conventional finite-element method (FEM)-based routines impose very large computational loads during generation/solving of the system equations. Therefore, other computational alternatives need to be explored. This paper outlines a three-dimensional finite-difference time-domain (FDTD) method in cylindrical coordinates for the modeling of low-frequency transient eddy currents in MRI, as an extension to the recently proposed time-harmonic scheme. The weakly coupled Maxwell's equations are adapted to the low-frequency regime by downscaling the speed of light constant, which permits the use of larger FDTD time steps while maintaining the validity of the Courant-Friedrich-Levy stability condition. The principal hypothesis of this work is that the modified FDTD routine can be employed to analyze pulsed-gradient-induced, transient eddy currents in superconducting MRI system models. The hypothesis is supported through a verification of the numerical scheme on a canonical problem and by analyzing undesired temporal eddy current effects such as the B-0-shift caused by actively shielded symmetric/asymmetric transverse x-gradient head and unshielded z-gradient whole-body coils operating in proximity to a superconducting MRI magnet.

The programming language python in earth system simulations

-scale vary from a planetary scale and million years for convection problems to 100km and 10 years for fault systems simulations. Various techniques are in use to deal with the time dependency (e.g. Crank-Nicholson), with the non-linearity (e.g. Newton-Raphson) and weakly coupled equations (e.g. non-linear Gauss-Seidel). Besides these high-level solution algorithms discretization methods (e.g. finite element method (FEM), boundary element method (BEM)) are used to deal with spatial derivatives. Typically, large-scale, three dimensional meshes are required to resolve geometrical complexity (e.g. in the case of fault systems) or features in the solution (e.g. in mantel convection simulations). The modelling environment escript allows the rapid implementation of new physics as required for the development of simulation codes in earth sciences. Its main object is to provide a programming language, where the user can define new models and rapidly develop high-level solution algorithms. The current implementation is linked with the finite element package finley as a PDE solver. However, the design is open and other discretization technologies such as finite differences and boundary element methods could be included. escript is implemented as an extension of the interactive programming environment python (see www.python.org). Key concepts introduced are Data objects, which are holding values on nodes or elements of the finite element mesh, and linearPDE objects, which are defining linear partial differential equations to be solved by the underlying discretization technology. In this paper we will show the basic concepts of escript and will show how escript is used to implement a simulation code for interacting fault systems. We will show some results of large-scale, parallel simulations on an SGI Altix system. Acknowledgements: Project work is supported by Australian Commonwealth Government through the Australian Computational Earth Systems Simulator Major National Research Facility, Queensland State Government Smart State Research Facility Fund, The University of Queensland and SGI.

Får jämställdheten plats? En studie av översiktsplaneringens behandling av sociala kategorier

Syftet med den här studien är att undersöka hur jämställdhet har behandlats i förhållande till övriga sociala kategorier i översiktsplaneringen. Vidare är syftet att undersöka om detta skiljer sig åt mellan olika typer av kommuner och över tid. Studien bygger på en intersektionell ansats och urvalet bygger på tidigare teorier kring genuskontrakt där fem kommuner i varje genuskontraktstyp inkluderas. Kommunernas översiktsplaner, både aktuella och äldre, studeras genom att genomföra en kvantitativ textanalys där sociala kategoriers utrymme undersöks och en diskursanalys där beskrivningen av sociala kategorier studeras. Resultatet visar att tio sociala kategorier inkluderas i översiktsplaneringen. Jämställdhet har gått från att få näst minst utrymme i de äldre översiktsplanerna till att idag få näst mest utrymme jämfört med övriga sociala kategorier. Jämställdhet beskrivs på liknande sätt som barn, funktionshindrade och äldre att gynnas av en nära, funktionsblandad stad med fungerande kollektivtrafik. Vilket genuskontrakt en kommun har påverkar främst hur kommunerna beskriver jämställdhet, mångfald och äldre.

Matematiklärares kommunikation i början och i slutet av ett kompetensutvecklingsprojekt

Sammanfattning Studiens fokus var dels vilka kategorier av innehåll som framkom i lärarnas kommunikation dels vilka förändringar i innehållet som uttolkades i matematiklärares kommunikation i början och i slutet av ett kompetensutvecklingsprojekt. Kontexten i kompetensutvecklingsprojektet var i form av modellen learning study, där sju lärarlag, sammanlagt 20 lärare deltagit. Ramverket i studien var tematisk analys, analys av matematiska kompetenser samt funktionell textanalys. Studiens resultat visar på flera förändringar, till exempel att de fem uttolkade huvudkategorierna innefattade fler underkategorier i slutet av kompetensutvecklingsprojektet. När det gäller matematiskt innehåll så visar analysen att lärarna kommunicerade matematika kompetenser på ett mer mångfacetterat sätt i slutet av kompetensutvecklingsprojektet. Då lärarna kommunicerade matematikundervisning använde de sig till viss del av ett annat sätt att uttrycka sig i slutet än i början av kompetensutvecklingsprojektet. I början talade de till exempel om att höra vad eleverna uttrycker till att i slutet använda sig av ordet lyssna. Resultatet visade även förändringar avseende hur lärarna samtalade om laborativt material. Fokus har flyttats från det laborativa materialet till att lärarna funderade över vilken matematik som eleverna uttryckte med hjälp av det laborativa materialet.  

Emotionsreglering vid dissonans

Dissonans uppstår när individers beteende och attityd inte är överensstämmande och attitydförändring minskar obehaget. Individers personlighet och exekutiva funktioner är kopplade till hur väl emotioner kan regleras. Studiens syfte var att undersöka dessa faktorers relation till dissonans och attitydförändring som emotionsreglerande strategi. Genom en internetbaserad enkätundersökning, uppdelad i fem delar, deltog 43 studenter från Stockholms Universitet. Enkäten tog ca 45 minuter att besvara och mätte personlighet, exekutiva funktioner, dissonans, attityder och emotioner. Resultatet visade på att personlighet och exekutiva funktioner till stor del mäter separata aspekter hos individer och att emotioner och attityd tydligt är sammankopplade. Personlighet och exekutiva funktioner bidrog båda till att förklara varians i såväl positiva som negativa emotioner. Reduktion av dissonans verkar således vara relaterat till emotionsreglering. 

Kineto-elastodynamic analysis of high-speed four-bar mechanism

This thesis addresses the kineto-elastodynamic analysis of a four-bar mechanism running at high-speed where all links are assumed to be flexible. First, the mechanism, at static configurations, is considered as structure. Two methods are used to model the system, namely the finite element method (FEM) and the dynamic stiffness method. The natural frequencies and mode shapes at different positions from both methods are calculated and compared. The FEM is used to model the mechanism running at high-speed. The governing equations of motion are derived using Hamilton's principle. The equations obtained are a set of stiff ordinary differential equations with periodic coefficients. A model is developed whereby the FEM and the dynamic stiffness method are used conjointly to provide high-precision results with only one element per link. The principal concern of the mechanism designer is the behaviour of the mechanism at steady-state. Few algorithms have been developed to deliver the steady-state solution without resorting to costly time marching simulation. In this study two algorithms are developed to overcome the limitations of the existing algorithms. The superiority of the new algorithms is demonstrated. The notion of critical speeds is clarified and a distinction is drawn between "critical speeds", where stresses are at a local maximum, and "unstable bands" where the mechanism deflections will grow boundlessly. Floquet theory is used to assess the stability of the system. A simple method to locate the critical speeds is derived. It is shown that the critical speeds of the mechanism coincide with the local maxima of the eigenvalues of the transition matrix with respect to the rotational speed of the mechanism.

Long period grating in multicore optical fiber:an ultra-sensitive vector bending sensor for low curvatures

Long period grating was UV inscribed into a multicore fiber consisting of 120 single mode cores. The multicore fiber that hosts the grating was fusion spliced into a single mode fiber at both ends. The splice creates a taper transition between the two types of fiber that produces a nonadiabatic mode evolution; this results in the illumination of all the modes in the multicore fiber. The spectral characteristics of this fiber device as a function of curvature were investigated. The device yielded a significant spectral sensitivity as high as 1.23 nm/m-1 and 3.57 dB/m-1 to the ultra-low curvature values from 0 to 1 m-1. This fiber device can also distinguish the orientation of curvature experienced by the fiber as the long period grating attenuation bands producing either a blue or red wavelength shift. The finite element method (FEM) model was used to investigate the modal behavior in multicore fiber and to predict the phase-matching curves of the long period grating inscribed into multicore fiber. © 2014 Optical Society of America.

Leak identification in saturated unsteady flow via a Cauchy problem

This work is an initial study of a numerical method for identifying multiple leak zones in saturated unsteady flow. Using the conventional saturated groundwater flow equation, the leak identification problem is modelled as a Cauchy problem for the heat equation and the aim is to find the regions on the boundary of the solution domain where the solution vanishes, since leak zones correspond to null pressure values. This problem is ill-posed and to reconstruct the solution in a stable way, we therefore modify and employ an iterative regularizing method proposed in [1] and [2]. In this method, mixed well-posed problems obtained by changing the boundary conditions are solved for the heat operator as well as for its adjoint, to get a sequence of approximations to the original Cauchy problem. The mixed problems are solved using a Finite element method (FEM), and the numerical results indicate that the leak zones can be identified with the proposed method.

Interpretation of the Superpave IDT strength test using a viscoelastic-damage constitutive model

This paper presents a new interpretation for the Superpave IDT strength test based on a viscoelastic-damage framework. The framework is based on continuum damage mechanics and the thermodynamics of irreversible processes with an anisotropic damage representation. The new approach introduces considerations for the viscoelastic effects and the damage accumulation that accompanies the fracture process in the interpretation of the Superpave IDT strength test for the identification of the Dissipated Creep Strain Energy (DCSE) limit from the test result. The viscoelastic model is implemented in a Finite Element Method (FEM) program for the simulation of the Superpave IDT strength test. The DCSE values obtained using the new approach is compared with the values obtained using the conventional approach to evaluate the validity of the assumptions made in the conventional interpretation of the test results. The result shows that the conventional approach over-estimates the DCSE value with increasing estimation error at higher deformation rates.

Electromagnetic design and loss calculations of a 1.12-MW high-speed permanent-magnet motor for compressor applications

Electromagnetic design of a 1.12-MW, 18 000-r/min high-speed permanent-magnet motor (HSPMM) is carried out based on the analysis of pole number, stator slot number, rotor outer diameter, air-gap length, permanent magnet material, thickness, and pole arc. The no-load and full-load performance of the HSPMM is investigated in this paper by using 2-D finite element method (FEM). In addition, the power losses in the HSPMM including core loss, winding loss, rotor eddy current loss, and air friction loss are predicted. Based on the analysis, a prototype motor is manufactured and experimentally tested to verify the machine design.

Design and analysis of a 2-DoF split-stator induction motor

A two degrees of freedom (2-DOF) actuator capable of producing linear translation, rotary motion, or helical motion would be a desirable asset to the fields of machine tools, robotics, and various apparatuses. In this paper, a novel 2-DOF split-stator induction motor was proposed and electromagnetic structure pa- rameters of the motor were designed and optimized. The feature of the direct-drive 2-DOF induction motor lies in its solid mover ar- rangement. In order to study the complex distribution of the eddy current field on the ferromagnetic cylinder mover and the motor’s operating characteristics, the mathematical model of the proposed motor was established, and characteristics of the motor were ana- lyzed by adopting the permeation depth method (PDM) and finite element method (FEM). The analytical and numerical results from motor simulation clearly show a correlation between the PDM and FEM models. This may be considered as a fair justification for the proposed machine and design tools.