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Model, Eric. "Creation and validation of the dual motivation profile scale." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0010101.
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Tahir, Mohammad Waseem. "Dual Scale Porosity and Interlaminar Properties of Composite Materials." Doctoral thesis, KTH, Lättkonstruktioner, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-145718.
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In the strive towards reduced fuel consumption and lower emissions, low structural weight is becoming a key factor in the design of advanced vehicle and aerospace structures. Whereas most traditional construction materials are seemingly reaching their limitations, composite materials with their high specific properties offer possibilities to further reduce weight. In high demand structural applications, the quality of the composite material is of utmost importance, requiring the material to be void free and the matrix well distributed as a binder for the load carrying reinforcement. To achieve proper wetting of the fibres, knowledge of the flow resistance of the porous fibre reinforcement is required. It is normally expressed in terms of permeability. Fibre reinforcements in composite materials are normally regarded as a heterogeneous porous media since both fabric and tows are porous but at different length scales. In order to numerically compute the permeability of such media, one of following two approaches can be used. Either filaments are added one-by-one into the modelled geometry (resolved model) or the tows are considered as porous homogenised media. In the latter case expression for the intra-tow permeability is needed. In this thesis, a porous homogenised tow model is benchmarked with a resolved model to the level of refinement possible without being too expensive computationally. Based on this approach, the permeability of complex three- dimensional (3D) textiles is computed utilizing computational fluid dynamics (CFD) analysis. The effect of inter- and intra-tow porosity on the overall permeability of 2D and 3D structures is analysed and discussed in relation to contradictions found in past studies. A clearer picture of the problem is presented, which will be helpful in future modelling and understanding of the permeability of complex structures. In an experimental study, the overall fibre volume fraction as well as the tow compaction are varied and their influence on the permeability is measured. Experimental studies show good agreement with numerical simulations. The interlaminar shear strength of thermoplastic composite materials is studied and the influence of specimen size is examined. Using finite element (FE) analysis it is shown that size effects may be partly due to statistical effects and partly due to the higher number of composite layers in thicker specimens. The effect of processing on the interlaminar delamination toughness of car-bon/polyamide 12 (C/PA12) is studied. It is observed that processing conditions have vital effect on the interlaminar delamination of thermoplastic composites. The mode I crack energy release rate (GIc) of C/PA12 is found to be 15 times higher than for conventional thermoset based composites and 1.5 times higher than for a thermoset composite with stitched reinforcement through the thickness. The best performing C/PA12 composite is manufactured in a hydraulic press equipped with a cold tool, thereby showing potential for both cost and time efficient manufacturing.QC 20150602
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Marcia, Roummel F. "Primal-dual interior-point methods for large-scale optimization /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2002. http://wwwlib.umi.com/cr/ucsd/fullcit?p3044769.
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Gowers, Richard. "Developing dual-scale models for structured liquids and polymeric materials." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/developing-dualscale-models-for-structured-liquids-and-polymeric-materials(edfe6991-79de-45a9-84e4-9e9dfb68faa4).html.
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Computer simulation techniques for exploring the microscopic world are quickly gaining popularity as a tool to complement theoretical and experimental approaches. Molecular dynamics (MD) simulations allow the motion of an N–body soft matter system to be solved using a classical mechanics description. The scope of these simulations are however limited by the available computational power, requiring the development of multiscale methods to make better use of available resources. Dual scale models are a novel form of molecular model which simultaneously feature particles at two levels of resolution. This allows a combination of atomistic and coarse-grained (CG) force fields to be used to describe the interactions between particles. By using this approach, targeted details in a molecule can be described at high resolution while other areas are treated with fewer degrees of freedom. This approach aims to allow for simulating the key features of a system at a reduced computational cost. In this thesis, two generations of a methodology for constructing dual scale models are presented and applied to various materials including polyamide, polyethene, polystyrene and octanol. Alongside a variety of well known atomistic force fields, these models all use iterative Boltzmann inversion (IBI) force fields to describe the CG interactions. In addition the algorithms and data structures for implementing dual scale MD are detailed, and expanded to include a multiple time step (MTS) scheme for optimising its peformance. Overall the IBI and atomistic force fields were compatible with each other and able to correctly reproduce the expected structural results. The first generation methodology featured bonds directly between atoms and beads, however these did not produce the correct structures. The second generation used only atomistic resolution bonds and this improved the intramolecular structures greatly for a relatively minor cost. In both the polyamide and octanol systems studied, the models were also able to properly describe the hydrogen bonding. For the CG half of the force field, it was possible to either use preexisting force field parameters or develop new parameters in situ. The resulting dynamical behaviour of the models was unpredictable and remains an open question both for CG and dual scale models. The theoretical performance of these models is faster than the atomistic counterpart because of the reduced number of pairwise interactions that must be calculated and this scaling was seen with the proposed reference implementation. The MTS scheme was successful in improving the performance with no effects on the quality of results. In summary this work has shown that dual scale models are able to correctly reproduce the structural behaviour of atomistic models at a reduced computational cost. With further steps towards making these models more accessible, they will become an exciting new option for many types of simulation.
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Balakrishnan, Anantaram, Thomas L. Magnanti, and Richard T. Wong. "A Dual Ascent Procedure for Large Scale Uncapacitated Network Design." Massachusetts Institute of Technology, Operations Research Center, 1987. http://hdl.handle.net/1721.1/5072.
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The fixed-charge network design problem arises in a variety of problem contexts including transportation, communication, and production scheduling.We develop a family of dual ascent algorithms for this problem. This approach generalizes known ascent procedures for solving shortest path, plant location,Steiner network and directed spanning tree problems. Our computational results for several classes of test problems with up to 500 integer and 1.98 million continuous variables and constraints shows that the dual ascent procedure and an associated drop-add heuristic generates solutions that, in almost all cases, are guaranteed to be within 1 to 3 percent of optimality. Moreover, the procedure requires no more than 150 seconds on an IBM 3083 computer. The test problems correspond to dense and sparse networks,including some models arising in freight transport.
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Tiziani, Cristina. "Processing and mechanical behaviour of dual scale particle strengthened copper." Tönning Lübeck Marburg Der Andere Verl, 2007. http://d-nb.info/986924059/04.
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Carr, Elliot Joseph. "Exponential integrators and a dual-scale model for wood drying." Thesis, Queensland University of Technology, 2012. https://eprints.qut.edu.au/58742/1/Elliot_Carr_Thesis.pdf.
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For the timber industry, the ability to simulate the drying of wood is invaluable for manufacturing high quality wood products. Mathematically, however, modelling the drying of a wet porous material, such as wood, is a diffcult task due to its heterogeneous and anisotropic nature, and the complex geometry of the underlying pore structure. The well{ developed macroscopic modelling approach involves writing down classical conservation equations at a length scale where physical quantities (e.g., porosity) can be interpreted as averaged values over a small volume (typically containing hundreds or thousands of pores). This averaging procedure produces balance equations that resemble those of a continuum with the exception that effective coeffcients appear in their deffnitions.
Exponential integrators are numerical schemes for initial value problems involving a system of ordinary differential equations. These methods differ from popular Newton{Krylov implicit methods (i.e., those based on the backward differentiation formulae (BDF)) in that they do not require the solution of a system of nonlinear equations at each time step but rather they require computation of matrix{vector products involving the exponential of the Jacobian matrix. Although originally appearing in the 1960s, exponential integrators have recently experienced a resurgence in interest due to a greater undertaking of research in Krylov subspace methods for matrix function approximation. One of the simplest examples of an exponential integrator is the exponential Euler method (EEM), which requires, at each time step, approximation of φ(A)b, where φ(z) = (ez - 1)/z, A E Rnxn and b E Rn.
For drying in porous media, the most comprehensive macroscopic formulation is TransPore [Perre and Turner, Chem. Eng. J., 86: 117-131, 2002], which features three coupled, nonlinear partial differential equations. The focus of the first part of this thesis is the use of the exponential Euler method (EEM) for performing the time integration of the macroscopic set of equations featured in TransPore. In particular, a new variable{ stepsize algorithm for EEM is presented within a Krylov subspace framework, which allows control of the error during the integration process. The performance of the new algorithm highlights the great potential of exponential integrators not only for drying applications but across all disciplines of transport phenomena. For example, when applied to well{ known benchmark problems involving single{phase liquid
ow in heterogeneous soils, the proposed algorithm requires half the number of function evaluations than that required for an equivalent (sophisticated) Newton{Krylov BDF implementation. Furthermore for all drying configurations tested, the new algorithm always produces, in less computational time, a solution of higher accuracy than the existing backward Euler module featured in TransPore.
Some new results relating to Krylov subspace approximation of '(A)b are also developed in this thesis. Most notably, an alternative derivation of the approximation error estimate of Hochbruck, Lubich and Selhofer [SIAM J. Sci. Comput., 19(5): 1552{1574, 1998] is provided, which reveals why it performs well in the error control procedure.
Two of the main drawbacks of the macroscopic approach outlined above include the effective coefficients must be supplied to the model, and it fails for some drying configurations, where typical dual{scale mechanisms occur. In the second part of this thesis, a new dual{scale approach for simulating wood drying is proposed that couples the porous medium (macroscale) with the underlying pore structure (microscale). The proposed model is applied to the convective drying of softwood at low temperatures and is valid in the so{called hygroscopic range, where hygroscopically held liquid water is present in the solid phase and water exits only as vapour in the pores. Coupling between scales is achieved by imposing the macroscopic gradient on the microscopic field using suitably defined periodic boundary conditions, which allows the macroscopic
ux to be defined as an average of the microscopic
ux over the unit cell. This formulation provides a first step for moving from the macroscopic formulation featured in TransPore to a comprehensive dual{scale formulation capable of addressing any drying configuration. Simulation results reported for a sample of spruce highlight the potential and flexibility of the new dual{scale approach. In particular, for a given unit cell configuration it is not necessary to supply the effective coefficients prior to each simulation.
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Hassard, Patrick. "Dual-scale modelling of two-dimensional flow in porous media." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/211518/1/Patrick_Hassard_Thesis.pdf.
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The standard approach to modelling fluid flow through a porous medium was developed decades ago, when computational resources were insufficient to feasibly simulate the flow directly. In this thesis, the feasibility of such flow simulation with modern computing power is demonstrated via the development of three accurate and efficient dual-scale models of porous media flow. An important outcome of the research is that the new dual-scale modelling framework accurately and efficiently simulates flows with a range of Reynolds numbers through a variety of heterogeneous porous media.
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Neacsu, Valentin. "Modeling and measurement of micro flow in dual scale porous media." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 280 p, 2010. http://proquest.umi.com/pqdweb?did=1998445961&sid=7&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Wright, Stephen E. "Convergence and approximation for primal-dual methods in large-scale optimization /." Thesis, Connect to this title online; UW restricted, 1990. http://hdl.handle.net/1773/5751.
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Madabushi, Ananth R. "Lagrangian Relaxation / Dual Approaches For Solving Large-Scale Linear Programming Problems." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36833.
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This research effort focuses on large-scale linear programming problems that arise in the context of solving various problems such as discrete linear or polynomial, and continuous nonlinear, nonconvex programming problems, using linearization and branch-and-cut algorithms for the discrete case, and using polyhedral outer-approximation methods for the continuous case. These problems arise in various applications in production planning, location-allocation, game theory, economics, and many engineering and systems design problems. During the solution process of discrete or continuous nonconvex problems using polyhedral approaches, one has to contend with repeatedly solving large-scale linear programming(LP) relaxations. Thus, it becomes imperative to employ an efficient method in solving these problems. It has been amply demonstrated that solving LP relaxations using a simplex-based algorithm, or even an interior-point type of procedure, can be inadequately slow ( especially in the presence of complicating constraints, dense coefficient matrices, and ill-conditioning ) in comparison with a Lagrangian Relaxation approach. With this motivation, we present a practical primal-dual subgradient algorithm that incorporates a dual ascent, a primal recovery, and a penalty function approach to recover a near optimal and feasible pair of primal and dual solutions.
The proposed primal-dual approach is comprised of three stages. Stage I deals with solving the Lagrangian dual problem by using various subgradient deflection strategies such as the Modified Gradient Technique (MGT), the Average Direction Strategy (ADS), and a new direction strategy called the Modified Average Direction Strategy (M-ADS). In the latter, the deflection parameter is determined based on the process of projecting the unknown optimal direction onto the space spanned by the current subgradient direction and the previous direction. This projected direction approximates the desired optimal direction as closely as possible using the conjugate subgradient concept. The step-length rules implemented in this regard are the Quadratic Fit Line Search Method and a new line search method called the Directional Derivative Line Search Method in which we start with a prescribed step-length and then ascertain whether to increase or decrease the step-length value based on the right-hand and left-hand derivative information available at each iteration. In the second stage of the algorithm (Stage II), a sequence of updated primal solutions is generated using some convex combinations of the Lagrangian subproblem solutions. Alternatively, a starting primal optimal solution can be obtained using the complementary slackness conditions. Depending on the extent of feasibility and optimality attained, Stage III applies a penalty function method to improve the obtained primal solution toward a near feasible and optimal solution.
We present computational experience using a set of randomly generated, structured, linear programming problems of the type that might typically arise in the context of discrete optimization.Master of Science
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Hu, Lin. "Oxidation of Single and Dual Phase NiCrAl(Y) Bond Coat Alloys." Cleveland, Ohio : Case Western Reserve University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1253714943.
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Thesis(Ph.D.)--Case Western Reserve University, 2009Title from PDF (viewed on 2009-12-22) Department of Materials Science and Engineering Includes abstract Includes bibliographical references and appendices Available online via the OhioLINK ETD Center
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Ashari, Alireza. "Dual-Scale Modeling of Two-Phase Fluid Transport in Fibrous Porous Media." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2326.
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The primary objective of this research is to develop a mathematical framework that could be used to model or predict the rate of fluid absorption and release in fibrous sheets made up of solid or porous fibers. In the first step, a two-scale two-phase modeling methodology is developed for studying fluid release from saturated/unsaturated thin fibrous media made up of solid fibers when brought in contact with a moving solid surface. Our macroscale model is based on the Richards’ equation for two-phase fluid transport in porous media. The required constitutive relationships, capillary pressure and relative permeability as functions of the medium’s saturation, are obtained through microscale modeling. Here, a mass convection boundary condition is considered to model the fluid transport at the boundary in contact with the target surface. The mass convection coefficient plays a significant role in determining the release rate of fluid. Moreover the release rate depends on the properties of the fluid, fibrous sheet, the target surface as well as the speed of the relative motion, and remains to be determined experimentally. Obtaining functional relationships for relative permeability and capillary pressure is only possible through experimentation or expensive microscale simulations, and needs to be repeated for different media having different fiber diameters, thicknesses, or porosities. In this concern, we conducted series of 3-D microscale simulations in order to investigate the effect of the aforementioned parameters on the relative permeability and capillary pressure of fibrous porous sheets. The results of our parameter study are utilized to develop general expressions for kr(S) and Pc(S). Furthermore, these general expressions can be easily included in macroscale fluid transport equations to predict the rate of fluid release from partially saturated fibrous sheets in a time and cost-effective manner. Moreover, the ability of the model has been extended to simulate the radial spreading of liquids in thin fibrous sheets. By simulating different fibrous sheets with identical parameters but different in-plane fiber orientations has revealed that the rate of fluid spread increases with increasing the in-plane alignment of the fibers. Additionally, we have developed a semi-analytical modeling approach that can be used to predict the fluid absorption and release characteristics of multi-layered composite fabric made up of porous (swelling) and soild (non-swelling) fibrous sheets. The sheets capillary pressure and relative permeability are obtained via a combination of numerical simulations and experiment. In particular, the capillary pressure for swelling media is obtained via height rise experiments. The relative permeability expressions are obtained from the analytical expressions previously developed with the 3-D microscale simulations, which are also in agreement with experimental correlations from the literature. To extend the ability of the model, we have developed a diffusion-controlled boundary treatment to simulate fluid release from partially-saturated fabrics onto surfaces with different hydrophilicy. Using a custom made test rig, experimental data is obtained for the release of liquid from partially saturated PET and Rayon nonwoven sheets at different speeds, and on two different surfaces. It is demonstrated that the new semi-empirical model redeveloped in this work can predict the rate of fluid release from wet nonwoven sheets as a function of time.
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Barnett, Nina (Kuentzer). "Permeability characterization and microvoid prediction during impregnation of fiber tows in dual-scale fabrics." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 2.70 Mb., 144 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:1430754.
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Suwanpinij, Piyada [Verfasser]. "Multi-scale modelling of hot rolled dual-phase steels for process design / Piyada Suwanpinij." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2013. http://d-nb.info/1030517010/34.
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Ulular, Osman. "A primal-dual conjugate subgradient algorithm for large- scale/specially structured linear programming problems." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/77750.
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This dissertation deals with a primal-dual conjugate subgradient-based algorithm for solving large-scale and/or specially structured linear programming problems. The proposed algorithm coordinates a Lagrangian dual function and a primal penalty function which satisfies a flexible set of specified properties, in order to generate a sequence of primal and dual iterates which can be shown to converge to an optimal pair of primal and dual solutions. Besides producing both primal and dual solutions, this coordination of primal and dual functions serves to guide the crucial choice of step-sizes in the iterative algorithm, and also provides a natural stopping criterion based on the duality gap. The generic algorithm maintains a considerable degree of flexibility which permits one to exploit any special structures inherent in the problem. Moreover, the algorithm admits a rich variety of admissible penalty functions and dual formulations in designing a particular implementation scheme. Other algorithmic strategies that can be gainfully employed to improve the performance of the algorithm include space-dilation and box step techniques, pattern search strategies and suboptimization based on complementary slackness conditions. The algorithm is tested on three different transportation problems with additional constraints which are faced by the Freight Equipment Management Program of the Association of American Railroads. Problem 1 is a maximin problem in which ∫(x) = minimum {∫,(x), r=1, ... , R} is maximized subject to the transportation constraints and a total cost constraint, where ∫, (·) is a savings function for the rth railroad, for r=1, ... , R. Problem 2 minimizes weighted absolute deviations of ∫, (x); r=1, ... , R from its mean value subject to the Problem 1 constraint set. Problem 3, on the other hand, minimizes total cost subject to the transportation constraints and the constraint which requires each ∫, (x), r=1, ... , R to be at least at some desired level. Both theoretical issues concerning convergence properties and rates, as well as algorithmic design and computational performance issues are investigated. The results indicate that the algorithm is a viable strategy for these problems. In particular, a new conjugate gradient strategy emerges as a byproduct of this algorithm, which is shown to dominate other available strategies on standard test problems from the literature.Ph. D.
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Wong, John Kam-wing. "Three-dimensional multi-scale hydraulic fracturing simulation in heterogeneous material using Dual Lattice Model." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/270542.
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Hydraulic fracturing is a multi-physics multi-scale problem related to natural processes such as the formation of dikes. It also has wide engineering applications such as extraction of unconventional resources, enhanced geothermal energy and carbon capture and storage. Current simulators are highly simplified because of the assumption of homogeneous reservoir. Unconventional reservoirs are heterogeneous owing to the presence of natural fracture network. Because of high computational effort, three-dimensional multi-scale simulations are uncommon, in particular, modelling material as a heterogeneous medium. Lattice Element Method (LEM) is therefore proposed for multi-scale simulation of heterogeneous material. In LEM, material is discretised into cells and their interactions are modelled by lattices, hence a three-dimensional model is simplified to a network of one-dimensional lattice. Normal, shear and rotational springs are used to define the constitutive laws of a lattice. LEM enables desktop computers for simulation of a lattice model that consists of millions of lattices. From simulations, normal springs govern the macroscopic bulk deformation while shear springs govern the macroscopic distortion. There is fluctuation of stresses even under uniform loading which is one of the characteristics of a lattice model. The magnitude increases with the stiffness ratio of shear spring to normal spring. Fracturing process can be modelled by LEM by introducing a microscopic tensile strength and a microscopic shear strength to the lattice properties. The strength parameters can be related to fracture toughness with the length scales of cells. From simulations, the relationships between model parameters and macroscopic parameters that are measurable in experiments are identified. From the simulations of uni-axial tension tests, both the spring stiffness ratio and the applied heterogeneity govern the fracturing process. The heterogeneity increases the ductility at the expense of the reduction on the macroscopic strengths. Different stages of fracturing are identified which are characterised by the model heterogeneity. Heterogeneous models go through the stages of the spatially distributed microscrack formation, the growth of multiple fracture clusters to the dominant fracture propagation. For homogeneous models, one of the microcracks rapidly propagates and becomes a dominant fracture with the absence of intermediate stages. From the uni-axial compression test simulations, the peak compressive stress is reached at the onset of the microscopic shear crack formation. Ductility is governed by the stiffness reduction ratio of a lattice in closed fractured stage to its unfractured stage. A novel Dual Lattice Model (DLM) is proposed for hydraulic fracture simulation by coupling a solid lattice model with a fluid lattice model. From DLM simulations of hydraulic fracturing of the classical penny shape crack problem under hydrostatic condition, the heterogeneities from both the fracture asperity and the applied heterogeneity increase the apparent fracture toughness. A semi-analytical solution is derived to consider the effect of fluid viscosity in the elastic deformation regime. Two asymptotes are identified that gives steep pressure gradients near the injection point and near the fracture tip which are also identified in the DLM simulations. Simulations also show three evolving regimes on energy dissipation/transfer mechanisms: the viscosity dominant, the elastic deformation dominant and the mixture of elastic deformation and toughness.
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Cao, Zhi. "Large-scale spatially extended atmospheric pressure plasma." Thesis, Loughborough University, 2010. https://dspace.lboro.ac.uk/2134/6688.
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This thesis presents experimental studies of low-temperature atmospheric pressure plasma sources with generic ability to effectively treat large-scale three-dimensional (3D) objects. The reported large-scale plasma sources are developed through parallelisation of single plasma jets. This strategy outshines the other reported strategies for treatment of uneven surfaces by being able to produce spatially extended plasma directly onto the surface of heavily three-dimensional objects. Comparable studies of the design of elemental plasma jets bring out a hybrid electrode configuration, the capillary-ring jet, as the best elemental jet to be used in the parallelisation. It is found that the introduction of a ballast resistor to the individual jet circuit or built-in capacitance is important to assure the jet-to-jet synchronism, stability and uniformity. Electrical and optical analyses of one-dimensional (1D) array of atmospheric pressure plasma jets demonstrate robust temporal and spatial jet-to-jet uniformity both for flat and sloped surfaces. Hexagonally-arranged two-dimensional (2D) arrays of atmospheric pressure plasma jets show good level of insusceptibility to variations of the downstream samples in their physical dimensions as well as structural and material properties. The reaction chemistry impact area of a 2D 37-jet array is estimated to be 18.6 cm2. These confirm the plasma jet arrays as a viable option as large-scale atmospheric plasma sources, well suited for many processing applications including plasma medicine. The spatially separated dual-frequency excitation further benefits the plasma jet in that separate control of different important plasma parameters is possible. Enhanced plasma properties achieved by the dual-frequency offer greater potential to the jet arrays.
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Joseph, Deepu Sebastian. "Wavelet Based Dual Time Scale Method for the Analysis of Cyclic Deformation of Polycrystalline Materials." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1261489948.
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Rahman, Md Hafizur. "Novel measurement of solids circulation rate in pilot-scale dual fluidized bed gasifier at high temperature." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/64150.
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A number of fluidized bed reactor processes operating at high temperature require that solid particles be circulated back and forth between two reactor vessels. Since the circulation rate strongly affects mass and energy balances, and therefore greatly influences hydrodynamics and performance of the system, a reliable technique for its accurate measurement would be helpful in monitoring and modeling the process. However, there are no reported techniques suitable for measuring this critical hydrodynamic parameter at elevated temperatures typical of gasification systems.
A novel thermal-tracing technique was developed for measuring the solids circulation rate between two vessels. Packets of particles at lower temperatures are injected into a downward-moving packed bed of solids at elevated temperature, creating reduced-temperature zones inside the moving bed. The transit time of the cold-particle-clusters between pairs of thermocouples is determined by cross correlation, allowing the flux to be estimated. The technique was shown to provide sensitive and reproducible data for a cold model unit with injection of dry ice. The technique was then applied to determine solids circulation rates between the bubbling bed gasifier and the riser combustor of a pilot scale dual fluidized bed gasification system. A number of conditions are imposed on the data to eliminate unsatisfactory data at high temperatures. Data which satisfy the discrimination criteria led to measured solids circulation fluxes up to 133 kg/m²s at temperatures up to 856°C in the gasifier test section.
A novel butterfly valve technique was developed to validate the thermal-tracing technique at high temperatures. Closing the valve causes solids to accumulate in the downcomer section of the pilot gasifier. The elevation of the top surface of these solids was tracked with high-temperature capacitance sensors, facilitating determination of the solids circulation flux between the two reactors of the pilot plant. The fluxes were also estimated using two indirect methods based on pressure balance and energy balance techniques. Agreement among the fluxes obtained from applying these four techniques are reasonable given the difficulty in measuring solids circulation rates.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
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Beaugeais, Katia. "Dual Role of a Composer-Performer: Creative Collaboration in New Australian Saxophone Music and Large-Scale Works." Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/24991.
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This PhD thesis examines the dual role of a composer-performer in various creative collaborative contexts. It is presented in two parts: (1) the role of a composer-performer in relation to one’s own compositions, and (2) the role of a composer-performer when performing other composers’ works.
Part 1 focuses on how my role as composer-saxophonist influences my compositional writing for saxophone and other instruments. Gestural production through the use of contemporary saxophone playing techniques to form the main motivic framework is discussed in relation to my saxophone concerto, saxophone orchestra, and didgeridoo and wind symphony work. Composition analyses illustrate avant-garde saxophone gestural effects in delicate, melodic solo settings, and in mass, fusion, textural sound block formations to create different sound worlds. My improvisatory stylistic composition approach and score graphic notation methods - including sensory aural and visual gestural devices and unconventional player positioning – allow for different ensemble interpretations, increased ensemble collaboration, surround sound spatialisation and enhanced audience communication.
Part 2 addresses the following interrelationship themes between composer and performer practice: performing composer acting as creative contributor; rarity of performer influencing the aesthetic structure of composers’ works; composer-performer interactional mechanisms to create a collective sharing approach; and score function acting as an important collaborative tool. Focus is placed upon the commissioning, creating and recording stages of new Australian saxophone music. Investigation into creative collaborative activity between composer-performer and composer during the rehearsal process highlights specific saxophone idiomatic issues that arose leading up to the international premiere performances and recording of the composers’ works for a 2019 ABC New Waves saxophone podcast and my ABC Classic solo saxophone album.
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Mukherjee, Valmiki. "A Dual Dielectric Approach for Performance Aware Reduction of Gate Leakage in Combinational Circuits." Thesis, University of North Texas, 2006. https://digital.library.unt.edu/ark:/67531/metadc5255/.
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Design of systems in the low-end nanometer domain has introduced new dimensions in power consumption and dissipation in CMOS devices. With continued and aggressive scaling, using low thickness SiO2 for the transistor gates, gate leakage due to gate oxide direct tunneling current has emerged as the major component of leakage in the CMOS circuits. Therefore, providing a solution to the issue of gate oxide leakage has become one of the key concerns in achieving low power and high performance CMOS VLSI circuits. In this thesis, a new approach is proposed involving dual dielectric of dual thicknesses (DKDT) for the reducing both ON and OFF state gate leakage. It is claimed that the simultaneous utilization of SiON and SiO2 each with multiple thicknesses is a better approach for gate leakage reduction than the conventional usage of a single gate dielectric (SiO2), possibly with multiple thicknesses. An algorithm is developed for DKDT assignment that minimizes the overall leakage for a circuit without compromising with the performance. Extensive experiments were carried out on ISCAS'85 benchmarks using 45nm technology which showed that the proposed approach can reduce the leakage, as much as 98% (in an average 89.5%), without degrading the performance.
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Hemmer, Julie. "Hydro-mechanical coupling in a deformable dual-scale fibrous reinforcement : from mesoscale characterization and modeling to liquid resin infusion process simulation." Thesis, Ecole centrale de Nantes, 2018. http://www.theses.fr/2018ECDN0044/document.
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L'un des objectifs de l'industrie éolienne est de produire de grandes pièces de structure à moindre coût. Dans ce contexte, la fabrication de pièces composites à partir de renforts quasi unidirectionnels(quasi-UD NCF) avec le procédé d’infusion est compétitive tant sur le plan mécanique que financier. Le procédé d'infusion engendre un phénomène de décompaction dû à la flexibilité de la bâche à vide. De plus les NCF présentent un écoulement à double échelle pendant leur imprégnation. La modélisation des deux phénomènes est souvent réalisée en supposant que la préforme fibreuse est un milieu continu à perméabilité variable. Néanmoins, la perméabilité est influencée par la répartition et la taille des mésopores, qui dépendent de l'état de compaction. Le but de cette thèse est de caractériser expérimentalement l'évolution d'un quasi-UD lors de l’infusion et d’évaluer l'impact de la réorganisation microstructurale sur des quantités macroscopiques d’intérêt, tels que la perméabilité et le temps de remplissage des pièces.Des infusions ont été réalisées à l'intérieur d'un tomographe pour capter l’évolution d’une même microstructure avant et après infusion. Un modèle simplifié a été proposé pour prédire la perméabilité dans le plan et ainsi évaluer l'influence de la réorganisation microstructurelle sur celle-ci. De plus,un outil numérique a été développé pour prendre en compte un écoulement double échelle dans un milieu fibreux déformable bidisperse. L'impact de la décompaction sur le temps de remplissage des pièces a été établi. Une étude mécanique expérimentale du comportement de la mèche tout au long de l’infusion a également été réalisée afin de mieux comprendre le comportement du quasi-UD. Un modèle hyperélastique a finalement été proposé pour prédire le comportement mécanique 3D des mèches pendant la phase de chargement à sec, avant l'infusionA current aim of wind turbine industries is to produce large structural parts at reduced costs. In this context, manufacture composite blades made of quasi-unidirectional non-crimp fabrics (quasi-UD NCF) using the infusion process is competitive on both mechanical and cost aspects. The infusion process involves an unloading phenomenon due to the vacuum bag flexibility. Additionally, during the impregnation, NCFs exhibit a dual-scale flow. Usual modeling of both phenomena assumes that the fibrous preform is a continuous medium with a varying permeability. Nonetheless, the permeability is affected by the meso-pores size and spatial distribution, which depend on the compaction state. The goal of this thesis is thus to characterize experimentally the flow-induced microstructural evolution of a quasi-UD NCF during the infusion process, and to quantify the impact of thismicrostructural reorganization on relevant macroscopic parameters, such as modelled in-plane permeability as well as computed filling time of parts. In situ infusion process has been conducted inside X-ray Computed Tomography device to capture a dual-scale fibrous microstructure prior and after the infusion process. Additionally, a simplified model has been proposed to predict the in-plane permeability and thus to evaluate the influence of the microstructural reorganization on it. Then, a numerical tool has been developed to account for dual-scale flow in a bidisperse deformable fibrous media. The impact of the dual-scale unloading on themacroscopic filling time of parts has been established. A mechanical investigation of the towbehavior during the infusion process has been additionally carried out experimentally to better understand the quasi-UD NCF behavior. From these results, a hyperelastic model has been proposed to predict the 3D mechanical behavior of tows during the dry loading phase, prior to the infusion process
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Theisen, Johannes. "Joint use of dual-frequency electrowetting and interferometry in a digital microsystem : application to evaporation and surface ageing at drop scale." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENI084/document.
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La recherche développée durant cette thèse constitue la première étape de développement d’une nouvelle méthodologie de détection sans marquage à l’échelle d’une goutte : un nouveau mécanisme de transduction est développé, basé sur l’actuation par électromouillage bi-fréquence d’un réseau d’ondes capillaires à la surface d’une goutte. La résonance capillaire de la goutte est étudiée par détection interférométrique de son apex en mouvement.La faisabilité de cette méthodologie est prouvée en caractérisant la cinétique d’évaporation de la goutte par glissement spectral des ondes capillaires.La deuxième partie de la thèse porte sur la modélisation du transport de biomolécules tensioactives dans une goutte : le transport diffusif, les processus d’ad/désorption aux surfaces, la condition cinématique d’un rayon variable(évaporation) ainsi qu’une quantité molaire finie de biomolécules sont pris en compte. Un nouveau nombre adimensionnel est proposé pour rendre compte de la taille finie d’une goutte. Puis le transport chimique associé au courant de dérive induit par les ondes capillaires (excitées par électromouillage oscillatoire)est pris en compte à l’aide de simulations numériques. Finalement,l’électromouillage haute et basse fréquence est appliqué au cas d’une goutte enrichie par des molécules d’albumine de sérum bovin. En utilisant conjointement l’interférométrie optique et l’imagerie, et en considérant la loi de Lippmann-Young, le vieillissement biochimique de la surface solide mouillée par la goutte est détectéThis PhD research is thought of as a first step towards label freedigital biosensing. A novel transduction mechanism is developed, based on thegeneration of capillary waves along a drop surface induced by dual-frequencyelectrowetting. Acapillary resonance is measured by interferometry at the movingdrop apex. Aproof of concept of this electro-optical methodology for furtherintegration in a digital microsystem is given with characterization of drop evaporationkinetics. A second part focuses on modeling and numerical calculationsof the transport of surface active biomolecules in the drop. The model includesdiffusion, ad-/desorption phenomena together with a kinematic condition of avariable drop radius (evaporation) as well as a finite molecular amount of surfaceactive biomolecules. A dimensionless number is suggested to take into accountfinite size effects. Drop steady streaming due to oscillating electrowetting isfinally taken into account. Low- and high-frequency electrowetting is appliedto a drop laden with bovine serum albumin. By jointly using interferometry andimaging, enhancement of surface ageing is made evident under electrowetting
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Khanal, Prayash. "Ammonium and orthophosphate ions removal from source separated human urine using dual reactive filters: A small scale laboratory study in a batch mode." Thesis, KTH, Mark- och vattenteknik (flyttat 20130630), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171845.
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The nutrients available in urine make it a good resource as fertilizer. Limited availability of natural phosphorus (P) is compelling people to think about recovering and returning it back to the land from waste stream. Urine comprising the majority of nitrogen (N) and P among other household wastewater, if managed separately, will benefit human against expensive commercial fertilizers, and eventually will reduce environmental problems. Various reactive filter systems have been studied since late 90’s as a potential system to recover N & P from urine and wastewater as a whole. Most studies are however limited to the laboratory scale only. Optimization of such technologies is one of the prime focuses in this area of research. This thesis project used the combination of two sorptive reactive materials, namely mordenite and polonite, to remove NH4-N and PO4-P from the source separated human urine. This two months laboratory scale study recommends dilution and storage to be a minimum pretreatment for urine. However as the influent’s NH4-N concentration was extremely high, further dilution or other relevant pretreatment is recommended. In overall, mordenite materials performed better for NH4-N removal reaching as high as 79% whereas polonite materials showed better results for PO4-P removal and the efficiency was as high as 97%. The reduction in NH4-N might also be due to the conversion of nitrogen into other forms. Mordenite materials showed a good potential for PO4-P removal and was up to 88% efficient initially. Both materials did not show the tendency of breakthrough for PO4-P until the end. The salinity measured as electric conductivity was reduced by both materials until about initial half-time period of the experiment. Since mordenite was the first unit to face the highly concentrated urine, it got saturated earlier and started showing the fluctuations in reduction and release for nutrients. The results obtained in this study provide the positive scenario for it to be implemented in the full scale system. However more elaborated studies in full scale addressing the major limitation of this project needs to be done before introducing the system for public uses.
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Bancora, Simone. "Characterization of fabric layups by pressure print analysis and simulation of dual-scale flow based on topological skeletonization : application to composite materials processing." Thesis, Ecole centrale de Nantes, 2021. http://www.theses.fr/2021ECDN0049.
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Dans cette thèse, nous nous intéressons aux préformes fibreuses dans le cadre du procédé Resin Transfer Moulding (RTM). L'objectif de la thèse est double : proposer une nouvelle méthodologie pour obtenir des données géométriques à la mésoéchelle des préformes et fournir un nouveau modèle numérique capable de prédire la perméabilité ou d'effectuer des simulations d’écoulement efficaces à la méso-échelle. Dans la première partie, l'accent est mis sur l'acquisition de données géométriques : nous proposons une nouvelle méthodologie basée sur l'analyse du champ de pression supporté par une préforme sèche sous compactage. Un film sensible à la pression mesure le champ de pression par un empilement de plis contre les parois du moule. Profitant de l’architecture périodique des textiles, les empreintes révélées par le champ de pression sont interprétées par analyse spectrale de Moiré pour mesurer l'orientation et la distribution spatiale de chaque couche dans l’empilement. Dans la seconde partie, le modèle numérique de la préforme est utilisé pour effectuer des simulations numériques d'écoulement à l'échelle des fils, afin d’en caractériser la perméabilité ou d’effectuer directement des simulations de remplissage. La géométrie 3D de l’empilement est remplacée par un squelette préservant les propriétés topologiques nécessaires à la résolution numérique du problème d'écoulement bidimensionnel, réduisant considérablement le coût de calcul par rapport à une approche 3D complète. Ce modèle de réduction du volume poreux en squelette est d'abord formulé dans sa version simple échelle (écoulement inter-mèche), puis étendu en double échelle (écoulement inter- et intra-mèche). Le potentiel du modèle est illustré à travers plusieurs cas tests. Cette recherche propose une méthodologie allant de l'acquisition de données géométriques à la simulation numérique double-échelle de l'écoulement au sein dans un empilement de tissusIn this work, we study continuous fiber preforms in the context of Resin Transfer Moulding (RTM) processes. The aim of the thesis is two-fold: propose a new methodology to obtain mesoscale geometrical data from preforms and provide a new numerical model able to predict permeability or perform mesoscale filling simulations in a computationally efficient way. In the first part, the focus is on the acquisition of geometrical data from preforms: we propose a novel methodology based on the analysis of the pressure field experienced by a dry preform under compaction. By using a commercial pressure-sensitive film, the pressure field exerted by a stack of layers against mould walls is captured and analyzed. Taking advantage of the periodic morphology of textiles, geometric patterns revealed by the pressure field are interpreted according to spectral Moiré analysis to recover the orientation and spatial distribution of each individual layer in the stack. In the second part, the reconstructed digital architecture of the preform is used to carry out numerical flow simulations at the scale of the yarns, to characterize permeability of the stack or directly perform filling simulations. The stack geometry is replaced by a skeletonized representation of the same, on which a two-dimensional flow problem can be solved numerically, greatly reducing the computational cost when compared to a full 3D approach. This “medial skeleton” model is first formulated in its single-scale version (flow in channels) and then extended to dual-scale (flow in channels and yarns). The model potential is illustrated through several test cases. This research establishes a pathway going from the non-destructive acquisition of data to the simulation of the dual-scale flow inside a multi-layer layup of textiles
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Gardenghi, John Lenon Cardoso. "Um método de pontos interiores primal-dual viável para minimização com restrições lineares de grande porte." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/45/45134/tde-11072014-084756/.
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Neste trabalho, propomos um método de pontos interiores para minimização com restrições lineares de grande porte. Este método explora a linearidade das restrições, partindo de um ponto viável e preservando a viabilidade dos iterandos. Apresentamos os principais resultados de convergência global, além de uma descrição rica em detalhes de uma implementação prática de todos os passos do método. Para atestar a implementação do método, exibimos uma ampla experimentação numérica, e uma análise comparativa com métodos bem difundidos na comunidade de otimização contínua.In this work, we propose an interior-point method for large-scale linearly constrained optimization. This method explores the linearity of the constraints, starting from a feasible point and preserving the feasibility of the iterates. We present the main global convergence results, together with a rich description of the implementation details of all the steps of the method. To validate the implementation of the method, we present a wide set of numerical experiments and a comparative analysis with well known softwares of the continuous optimization community.
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Soares, Gambarini Gabriela. "Influence of highly contrasted dual-scale porosity carbon interlock fabrics on permeability, flow-induced deformation and saturation during CRTM process : Experimental characterization and modeling." Electronic Thesis or Diss., Ecole centrale de Nantes, 2023. http://www.theses.fr/2023ECDN0018.
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Un premier objectif de cette thèseest de développer une méthodologie de mesurede perméabilité qui caractérise avec précision letenseur complet de perméabilité d'un tissu eninterlock en carbone utilisé dans la fabricationdes aubes de turbine d’avion par le procédé CRTM.Les caractéristiques uniques du tissu,notamment ses épaisseur et rigidité élevées,ses fibres opaques et sa double échelle deporosité très marquée, présentent des défis lorsde l'utilisation de techniques de mesuretraditionnelles.Afin de mesurer le tenseur complet deperméabilité de façon économique et sur uneplage étendue de fraction volumique de fibres,une combinaison de méthodes expérimentales aété proposée et utilisée.Les travaux portent également sur l’étude del'apparition de déformations du réseau fibreuxinduites par l'écoulement et propose une fenêtredeprocédé optimale pour imprégner les interlockslors du procédé C-RTM.Le développement d'un banc d'essaiexpérimental pour mesurer la saturationpendant l'injection est présenté, ainsi quel'influence de sa double échelle de porosité trèsmarquée. Les résultats sont complétés par unemodélisation numérique préliminaire à l’échellemésoscopique d'une géométrie simplifiéereprésentative.Les défis posés par la double échelle marquéede l’espace poral et les modes d’imprégnationdu tissu en interlock qui en découlent, justifientde l’approche proposée, combinant analyseexpérimentale et modélisation, qui doit êtrepoursuivie pour approfondir l’étude de cesmécanismesA primary objective of this thesis is to developa permeability measurement methodology thataccurately characterizes the full permeabilitytensor of a carbon interlock fabric used in themanufacture of aircraft turbine blades using theC-RTM process. The unique characteristics ofthe fabric, including its high thickness andstiffness, its non-transparent fibers and itspronounced dual-porosity scale, presentchallenges when using traditional measurementtechniques.In order to measure the full permeability tensoreconomically and over a wide range of fibervolume fractions, a combination of experimentalmethods has been proposed and applied.The development of an experimental testbench to measure saturation during injectionand the influence of its very strong doubleporosity scale is presented. The results arecomplemented by preliminary mesoscopicnumerical modelling of a representativesimplified geometry.The challenges posed by the pronounceddouble scale of the pore space and the resultingmodes of impregnation of the interlocked fabricjustify the proposed approach of combiningexperimental analysis and modelling, whichmust be pursued in order to study thesemechanisms in greater depth
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Silveti, Falls Antonio. "First-order noneuclidean splitting methods for large-scale optimization : deterministic and stochastic algorithms." Thesis, Normandie, 2021. http://www.theses.fr/2021NORMC204.
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Dans ce travail, nous développons et examinons deux nouveaux algorithmes d'éclatement du premier ordre pour résoudre des problèmes d'optimisation composites à grande échelle dans des espaces à dimensions infinies. Ces problèmes sont au coeur de nombres de domaines scientifiques et d'ingénierie, en particulier la science des données et l'imagerie. Notre travail est axé sur l'assouplissement des hypothèses de régularité de Lipschitz généralement requises par les algorithmes de fractionnement du premier ordre en remplaçant l'énergie euclidienne par une divergence de Bregman. Ces développements permettent de résoudre des problèmes ayant une géométrie plus exotique que celle du cadre euclidien habituel. Un des algorithmes développés est l'hybridation de l'algorithme de gradient conditionnel, utilisant un oracle de minimisation linéaire à chaque itération, avec méthode du Lagrangien augmenté, permettant ainsi la prise en compte de contraintes affines. L'autre algorithme est un schéma d'éclatement primal-dual incorporant les divergences de Bregman pour le calcul des opérateurs proximaux associés. Pour ces deux algorithmes, nous montrons la convergence des valeurs Lagrangiennes, la convergence faible des itérés vers les solutions ainsi que les taux de convergence. En plus de ces nouveaux algorithmes déterministes, nous introduisons et étudions également leurs extensions stochastiques au travers d'un point de vue d'analyse de stablité aux perturbations. Nos résultats dans cette partie comprennent des résultats de convergence presque sûre pour les mêmes quantités que dans le cadre déterministe, avec des taux de convergence également. Enfin, nous abordons de nouveaux problèmes qui ne sont accessibles qu'à travers les hypothèses relâchées que nos algorithmes permettent. Nous démontrons l'efficacité numérique et illustrons nos résultats théoriques sur des problèmes comme la complétion de matrice parcimonieuse de rang faible, les problèmes inverses sur le simplexe, ou encore les problèmes inverses impliquant la distance de Wasserstein régulariséeIn this work we develop and examine two novel first-order splitting algorithms for solving large-scale composite optimization problems in infinite-dimensional spaces. Such problems are ubiquitous in many areas of science and engineering, particularly in data science and imaging sciences. Our work is focused on relaxing the Lipschitz-smoothness assumptions generally required by first-order splitting algorithms by replacing the Euclidean energy with a Bregman divergence. These developments allow one to solve problems having more exotic geometry than that of the usual Euclidean setting. One algorithm is hybridization of the conditional gradient algorithm, making use of a linear minimization oracle at each iteration, with an augmented Lagrangian algorithm, allowing for affine constraints. The other algorithm is a primal-dual splitting algorithm incorporating Bregman divergences for computing the associated proximal operators. For both of these algorithms, our analysis shows convergence of the Lagrangian values, subsequential weak convergence of the iterates to solutions, and rates of convergence. In addition to these novel deterministic algorithms, we introduce and study also the stochastic extensions of these algorithms through a perturbation perspective. Our results in this part include almost sure convergence results for all the same quantities as in the deterministic setting, with rates as well. Finally, we tackle new problems that are only accessible through the relaxed assumptions our algorithms allow. We demonstrate numerical efficiency and verify our theoretical results on problems like low rank, sparse matrix completion, inverse problems on the simplex, and entropically regularized Wasserstein inverse problems
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Qaadan, Sahar [Verfasser], Tobias [Gutachter] Glasmachers, and Laurenz [Gutachter] Wiskott. "Budgeted stochastic coordinate ascent for large-scale kernelized dual support vector machine training / Sahar Qaadan ; Gutachter: Tobias Glasmachers, Laurenz Wiskott ; Fakultät für Elektrotechnik und Informationstechnik." Bochum : Ruhr-Universität Bochum, 2020. http://d-nb.info/1202608981/34.
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Qa'adan, Sahar [Verfasser], Tobias [Gutachter] Glasmachers, and Laurenz [Gutachter] Wiskott. "Budgeted stochastic coordinate ascent for large-scale kernelized dual support vector machine training / Sahar Qaadan ; Gutachter: Tobias Glasmachers, Laurenz Wiskott ; Fakultät für Elektrotechnik und Informationstechnik." Bochum : Ruhr-Universität Bochum, 2020. http://d-nb.info/1202608981/34.
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Kumar, Ravi R. "NUMERICAL INVESTIGATION AND PARALLEL COMPUTING FOR THERMAL TRANSPORT MECHANISM DURING NANOMACHINING." UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_theses/425.
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Nano-scale machining, or Nanomachining is a hybrid process in which the total thermal energy necessary to remove atoms from a work-piece surface is applied from external sources. In the current study, the total thermal energy necessary to remove atoms from a work-piece surface is applied from two sources: (1) localized energy from a laser beam focused to a micron-scale spot to preheat the work-piece, and (2) a high-precision electron-beam emitted from the tips of carbon nano-tubes to remove material via evaporation/sublimation. Macro-to-nano scale heat transfer models are discussed for understanding their capability to capture and its application to predict the transient heat transfer mechanism required for nano-machining. In this case, thermal transport mechanism during nano-scale machining involves both phonons (lattice vibrations) and electrons; it is modeled using a parabolic two-step (PTS) model, which accounts for the time lag between these energy carriers. A numerical algorithm is developed for the solution of the PTS model based on explicit and implicit finite-difference methods. Since numerical solution for simulation of nanomachining involves high computational cost in terms of wall clock time consumed, performance comparison over a wide range of numerical techniques has been done to devise an efficient numerical solution procedure. Gauss-Seidel (GS), successive over relaxation (SOR), conjugate gradient (CG), d -form Douglas-Gunn time splitting, and other methods have been used to compare the computational cost involved in these methods. Use of the Douglas-Gunn time splitting in the solution of 3D time-dependent heat transport equations appears to be optimal especially as problem size (number of spatial grid points and/or required number of time steps) becomes large. Parallel computing is implemented to further reduce the wall clock time required for the complete simulation of nanomachining process. Domain decomposition with inter-processor communication using Message Passing Interface (MPI) libraries is adapted for parallel computing. Performance tuning has been implemented for efficient parallelization by overlapping communication with computation. Numerical solution for laser source and electron-beam source with different Gaussian distribution are presented. Performance of the parallel code is tested on four distinct computer cluster architecture. Results obtained for laser source agree well with available experimental data in the literature. The results for electron-beam source are self-consistent; nevertheless, they need to be validated experimentally.
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Philippot, Clément. "Etude des mécanismes de précipitation, de recristallisation et de transformation de phases dans les aciers Dual Phase microalliés au titane niobium lors du recuit." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4342.
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L’allégement des véhicules est l’un des objectifs prioritaires des constructeurs automobile pour répondre aux directives environnementales d’émission de CO2. Le développement des aciers multiphasés à très haute résistance mécanique est l’une des solutions communément adoptées pour réduire l’épaisseur des tôles dans les véhicules tout en conservant leur capacité à assurer la sécurité des passagers. La présente étude porte sur l’optimisation des paramètres du procédé de production industrielle de l’une des ces familles d’aciers : les aciers Dual Phase microalliés au titane et au niobium de haut grade ; c'est-à-dire possédant une résistance à la rupture supérieure à 800MPa.A partir d’une microstructure initiale bainite + martensite laminée à froid, les différents phénomènes se produisant au cours du recuit, de la chauffe jusqu’à la fin du maintien intercritique, sont caractérisés. L’influence des paramètres du recuit comme la vitesse de chauffe, la température et le temps de maintien est étudiée. Le système d’interactions triple entre la précipitation des éléments de microalliage, la recristallisation et la formation de l’austénite est au cœur du problème. Un scénario des évolutions microstructurales a été établi à partir de la caractérisation des divers phénomènes. La finesse de la microstructure étudiée (sub-micrométrique) a nécessité l’emploi combiné de techniques de caractérisation multi-échelles : MEB, MET, sonde atomique tomographique, nano-SIMSLightening the weight of vehicles is one of the main challenging objectives of the automotive industry to reach the environmental regulation in term of CO2 emissions. The development of multiphase high strength steels is a common solution to reduce the thickness of sheet steel used in vehicles while keeping the same level of passenger’s safety requirements. The present study deals with the optimization of industrial process parameters applied to obtain one of these steels: the high strength microalloyed Dual Phase steels; i.e. with ultimate tensile strength superior to 800MPa.From an initial cold rolled microstructure made of bainite + martensite, the phenomena occurring during the annealing are characterized since the heating up to the end of the intercritical holding. The influence of process parameters as the heating rate, the holding temperature and the holding time are studied. The triple interactions system between the precipitation of microalloying elements, the recrystallization and the austenite formation is the core of the problem. A scenario of microstructural evolutions has been established based on the characterized phenomena. The studied fine microstructure (sub-microns) requires the combination of multiscale characterization techniques: SEM, TEM, atom probe tomography, nano-SIMS
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Uran, Matthias [Verfasser], Axel [Gutachter] Klawonn, Oliver [Gutachter] Rheinbach, and Jörg [Gutachter] Schröder. "High-Performance Computing Two-Scale Finite Element Simulations of a Contact Problem Using Computational Homogenization - Virtual Forming Limit Curves for Dual-Phase Steel / Matthias Uran ; Gutachter: Axel Klawonn, Oliver Rheinbach, Jörg Schröder." Köln : Universitäts- und Stadtbibliothek Köln, 2020. http://d-nb.info/1215837089/34.
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Ratheesh, Greeshma. "Fabrication of hierarchical scaffold and the development of patient-specific bioink for bone tissue engineering." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/210168/1/Greeshma_Ratheesh_Thesis.pdf.
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Tissue engineering provides a potential solution for the repair and regeneration of bone defects and fractures healing. A biomedical scaffold is one of the ideal approaches to achieve effective structure for bone cell growth and bone formation in the desired shape. This study has developed an ideal three-dimensional scaffold architecture with improved biological functionality, which has a physically stable and structurally porous shape, with interconnected channels and defined topography for guided bone regeneration.
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Imbert, Mathieu. "High speed reactive RTM with on-line mixing in dualscale fibrous reinforcements : Experimental and numerical developments and investigations." Thesis, Ecole centrale de Nantes, 2017. http://www.theses.fr/2017ECDN0017/document.
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Le moulage RTM à haute cadence est un procédé de fabrication composite prometteur qui satisfait les exigences de l’industrie automobile pour produire des pièces structurelles complexes avec un temps de cycle court. Cependant, les réductions de temps de cycle sont un véritable défi. Dans ce procédé, une résine est injectée avec mélange en dans la cavité d’un moule contenant un renfort fibreux. Ce flux de résine réactive génère des schémas d’écoulement complexes et des couplages thermo-chimio-rhéologiques forts. En raison de la grande sensibilité de la résine et des temps de cycle serrés, la prédiction de la stratégie d’injection optimale est très difficile et très coûteuse à mener expérimentalement. Le travail réalisé a donc poursuivi deux objectifs: 1. Identifier et quantifier expérimentalement les mécanismes influençant le procédé RTM réactif avec mélange en tête et 2. Développer une méthode de simulation numérique en vue d’introduire les mécanismes identifiés dans le logiciel industriel PAM COMPOSITE développé par ESI Group. L’identification et la quantification des mécanismes ont été réalisées grâce à des investigations expérimentales et numériques. Un nouveau montage expérimental a été développé pour l’étude du mécanisme de stockage de résines intra-mèche grâce à des observations aux échelles macro- et microscopiques. De plus, une méthode numérique a été développée pour simuler l’écoulement réactif de la résine dans des matériaux à simple et à double échelle de porosité. Cette méthode a permis d’étudier les mécanismes locaux difficiles à mesurer expérimentalement et de préparer le transfert vers le logiciel industriel d’ESIHigh Speed Resin Transfer Molding (RTM) is a promising composite manufacturing process fitting automotive industry requirements to produce complex structural parts with a perspective of short cycle times. However, cycle time reductions are a real challenge. In this process, a resin mixed on-line with curing agents is injected in the cavity of a mold containing a fibrous reinforcement. This flow of reactive resin generates acomplex flow pattern and strong thermo-chemo rheological couplings. Due to the high sensitivity of the resin cure, and the tight cycle times, prediction of the optimal injection strategy is very difficult and very expensive to conduct experimentally. In this context, two goals where followed in this work: 1. Identify and quantify experimentally the mechanisms, related to the process or to the reinforcement, influencing the reactive RTMprocess with on-line mixing and 2. Develop a numerical simulation method in a view of introducing the identified mechanisms in the industrial software PAMCOMPOSITE developed by ESI Group. Identification and quantification of the mechanisms were realized thanks to experimental investigations and numerical simulations. A new experimental setup has been developed for the investigation of the mechanism of intra-tow resin storage through macro-scale and micro-scale observations. Additionally, a numerical method has been developed to simulate the reactive flow of a resin in single and dual scale porous materials. This method allowed both to investigate local mechanisms difficult to study experimentally and prepare the transfer to the industrial software of ESI
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Bird, Gareth Edward. "The coupled dual boundary element-scaled boundary finite element method for efficient fracture mechanics." Thesis, Durham University, 2012. http://etheses.dur.ac.uk/6996/.
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A novel numerical method is presented for applications to general fracture mechanics problems in engineering. The coupled dual boundary element-scaled boundary finite element method (DBE-SBFEM) incorporates the numerical accuracy of the SBFEM and the geometric versatility of the DBEM. Background theory, detailed derivations and literature reviews accompany the extensions made to the methods constituents necessary for their coupling as part of the present work. The coupled DBE-SBFEM, its constituent components and their application to linear elastic fracture mechanics are critically assessed and presented with numerical examples to demonstrate both method convergence and improvements over previous work. Further, a proof of concept demonstrates an alternative formation of the DBEM that both negates the need for hyper-singular integration and lends itself to a wider variety of imposed boundary conditions. Conclusions to this work are drawn and further recommendations for research in this area are made.
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Anand, Vivek. "Modelling and Control of a Dual Sided Linear Induction Motor for a scaled Hyperloop Pod." Thesis, KTH, Fordonsdynamik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-285801.
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The electrification era has been marked up by an increase in volume of electric vehicles which are directly or indirectly powered by electricity. Railways, roadways and airways are being electrified as we speak at their own respective rate. In addition to that upcoming concepts for transport solution such as hyperloop also described as the fifth mode of transportation will be electrified. The current thesis work is based on developing the model and control of the propulsion system of a scaled Hyperloop pod designed by student team KTH Hyperloop representing KTH. The team competes in Hyperloop competition organized by Spacex and the goal is to achieve the highest possible speed in a given distance and track designed by SpaceX. In order to achieve the goal of being the fastest, the scaled pod uses a Double Sided Linear Induction Motor (DSLIM) as mentioned in the subsequent chapter. The motor modelling is done on Simulink and is similar to a rotary induction motor (RIM). However the presence of end effect in DSLIM makes it different from RIM and has been discussed subsequently. The control strategy uses a synchronous frame PI control for the current control and sensor based speed control for controlling the speed of the pod.The speed control output is a reference current which is used as an input to the current controller which finally gives voltage as the control output. The corresponding bandwidth for the various loops have been calculated based on motor parameters as discussed in the method section. The validation of the motor model and the corresponding controller has been discussed in the result section, where the accuracy of the controller for the designed modelled is discussed.Elektrifieringstiden har präglats av en ökning i volym av elfordon som direkt eller indirekt drivs med el. Järnvägar, vägar och luftvägar elektrifieras just nu med deras respektive takt. Utöver det kommer kommande koncept för transportlösning som hyperloop som också beskrivs som det femte transportsättet att elektrifieras. Detta examensarbete bygger på att utveckla modellen och regleringen av framdrivningssystemet för en nedskalad Hyperloop-pod utvecklad av studentteamet KTH Hyperloop som representerar KTH. Teamet tävlar i Hyperloop-tävlingen organiserad av SpaceX och målet är att uppnå högsta möjliga hastighet på ett visst avstånd och spår framtaget av SpaceX. För att uppnå målet om att vara snabbast använder den nedskalade podden en dubbelsidig elektrisk linjär induktionsmotor (DSLIM) som nämns i det följande kapitlet. Den elektriska motormodelleringen görs i Simulink och liknar en roterande induktionsmotor(RIM). Men närvaron av ’end effect’ i DSLIM gör den annorlunda än RIM och har diskuterats därefter. Styrstrategin använder en synkron ram-PI-styrning för strömstyrning och sensorbaserad hastighetsreglering för att styra hastigheten på podden. Varvtalsstyrningsutgången är en referensström som används som en ingång till den nuvarande styrenheten som slutligen ger spänning som slutling styrning. Motsvarande bandbredd för de olika slingorna har beräknats baserat på elektriska motorparametrar som diskuterats i metodavsnittet.Valideringen av elmotormodellen och motsvarande styrenhet har diskuterats i resultatsektionen, där noggrannheten hos styrenheten för den konstruerade modellerna diskuteras.
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Hairaye, Camille. "Fonctionnalisation de surfaces par microstructuration laser." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAD013/document.
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Cette thèse porte sur la fonctionnalisation de surface par microstructuration laser. L’étude expérimentale a consisté à texturer des surfaces d’acier inoxydable avec une source laser impulsionnelle à fibre dopée Yb (1030 nm, 300 fs), dans le but de contrôler leur mouillabilité et de les rendre superhydrophobes. Par une optimisation des conditions d’irradiation, il est possible de conférer à la surface une structuration à double échelle de rugosité. Des structures d’une dizaine de micromètres sont réalisées par ablations successives selon un motif de lignes croisées, sur lesquelles se forment des nanostructures auto-organisées. La simulation du couplage de l’énergie dans la cible a permis de déterminer les paramètres opératoires pour limiter l’accumulation thermique en surface. L’étude fait clairement apparaître le rôle de la texturation dans l’apparition du caractère superhydrophobe de la surface, tout en soulignant l’influence des propriétés physico-chimiques du matériauThis PhD thesis is about surface functionalization by laser microstructuring. The experimental study consists in texturing stainless steel surfaces with a pulsed Yb fibre laser source (1030 nm, 300 fs), in order to control their wettability and confer to them superhydrophobic properties. With an optimization of the irradiating conditions on the target, it is possible to confer to the surface a dual-scale roughness. By successive ablations according to a pattern of crossed lines, microstructures in the range of tens of micrometres are realized, on which self-organized nanostructures are superimposed. Simulation of the energy coupling in the material allows to determine the process parameters to be used, in order to limit the thermal accumulation and avoid the melting of the surface. This study reveals the role of the laser texturing in the apparition of the superhydrophobic character and emphasizes the influence of the physicochemical properties of the material
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Klayman, Benjamin Joseph. "A quantitative description at multiple scales of observation of accumulation and displacement patterns in single and dual-species biofilms." Diss., Montana State University, 2007. http://etd.lib.montana.edu/etd/2007/klayman/KlaymanB0807.pdf.
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Cordesse, Pierre. "Contribution to the study of combustion instabilities in cryotechnic rocket engines : coupling diffuse interface models with kinetic-based moment methods for primary atomization simulations." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASC016.
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Gardiens de l’espace, les lanceurs de fusée font l’objet d’une amélioration continue et concurrentielle, grâce à des campagnes de tests expérimentaux et numériques. Les simulations prédictives sont devenues indispensables pour accroître notre compréhension de la physique. Ajustables, elles se prêtent parfaitement à la conception et l’optimisation, en particuliers de la chambre de combustion, pour garantir la sureté et maximiser l’efficacité. L’atomisation primaire est l’un des phénomènes déterminants de la combustion du combustible et de l’oxydant, pilotant à la fois la distribution de gouttes et les potentielles instabilités hautes-fréquences en conditions sous-critiques. Elle couvre un large spectre de topologies d’écoulement diphasique, depuis ceux de type phases séparées jusqu’à la phase dispersée, en passant par une région mixte caractérisée par la complexité de la physique à petites échelles et de la topologie de l’écoulement. Les modèles d’ordre réduit constituent de bons candidats pour réaliser des simulations numériques prédictives et relativement peu coûteuses en ressource de calcul sur des configurations industrielles. Cependant, jusqu’à présent ils ne décrivent correctement que la dynamique des grandes échelles et doivent donc être couplés à des modèles de phase dispersée nécessitant un réglage minutieux de paramètres pour prédire la formation du spray. Afin de décrire à la fois les régions mixte et dispersée, l’amélioration de la hiérarchie de modèles d’ordre réduit repose sur quelques principes clefs au cœur de la thèse ci-présente et fournit des problèmes interdisciplinaires faisant appel tant à l’analyse mathématique et la modélisation physique de ces systèmes d’EDP qu’à leur discrétisation numérique et leur implémentation dans des codes de CFD à des fins industriels. Grâce d’une part à l’extension de la théorie des équations de conservation supplémentaires à des systèmes impliquant des termes non-conservatifs et d’autre part à un formalisme de thermodynamique multi-fluide tenant compte des effets non-idéaux, nous proposons de nouvelles pistes pour définir une entropie de mélange strictement convexe et consistante avec le système d’équation et les lois de pression, dans le but de permettre la symmétrisation entropique des modèles diphasiques, de prouver leur hyperbolicité et d’obtenir des termes sources généraux. De plus, en rompant avec la vision géométrique de l’interface, nous proposons une description multi-échelle de l’interface pour décrire un mélange multi-fluide comportant une dynamique interfaciale complexe. Le Principe de Moindre Action a permis de dériver un modèle bifluide à une vitesse couplant grandes et petites échelles de l’écoulement. Nous avons ensuite développé une stratégie de séparation d’opérateurs basée sur la discrétisation par Volumes Finis, et nous avons implémenté le nouveau modèle dans le logiciel industriel multiphysique de CFD, CEDRE, de l’ONERA afin d’évaluer numériquement ce dernier. Enfin, nous avons construit et analysé les fondations d’une hiérarchie de cas tests accessibles à la DNS tout en étant au plus proche de configurations industrielles, dans le but d’évaluer les résultats de simulations du nouveau modèle ou de tout autre modèle à venirGatekeepers to the open space, launchers are subject to intense and competitive enhancements, through experimental and numerical test campaigns. Predictive numerical simulations have become mandatory to increase our understanding of the physics. Adjustable, they provide early-stage optimization processes, in particular of the combustion chamber, to guaranty safety and maximize efficiency. One of the major physical phenomenon involved in the combustion of the fuel and oxidizer is the jet atomization, which pilotes both the droplet distributions and the potential high-frequency instabilities in subcritical conditions. It encompasses a large sprectrum of two-phase flow topologies, from separated phases to disperse phase, with a mixed region where the small scale physics and topology of the flow are very complex. Reduced-order models are good candidates to perform predictive but low CPU demanding simulations on industrial configurations but have only been able so far to capture large scale dynamics and have to be coupled to disperse phase models through adjustable and weakly reliable parameters in order to predict spray formation. Improving the hierarchy of reduced order models in order to better describe both the mixed region and the disperse region requires a series of building blocks at the heart of the present work and give on to complex problems in the mathematical analysis and physical modelling of these systems of PDE as well as their numerical discretization and implementation in CFD codes for industrial uses. Thanks to the extension of the theory on supplementary conservative equations to system of non-conservation laws and the formalism of the multi-fluid thermodynamics accounting for non-ideal effects, we give some new leads to define a strictly convex mixture entropy consistent with the system of equations and the pressure laws, which would allow to recover the entropic symmetrization of two-phase flow models, prove their hyperbolicity and obtain generalized source terms. Furthermore, we have departed from a geometric approach of the interface and proposed a multi-scale rendering of the interface to describe multi-fluid flow with complex interface dynamics. The Stationary Action Principle has returned a single velocity two-phase flow model coupling large and small scales of the flow. We then have developed a splitting strategy based on a Finite Volume discretization and have implemented the new model in the industrial CFD software CEDRE of ONERA to proceed to a numerical verification. Finally, we have constituted and investigated a first building block of a hierarchy of test-cases designed to be amenable to DNS while close enough to industrial configurations in order to assess the simulation results of the new model but also to any up-coming models
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Léon, Olivier. "Étude du rayonnement acoustique d'instabilités hydrodynamiques de jets double-flux par les équations de stabilité parabolisées (PSE)." Phd thesis, Toulouse, INPT, 2012. http://oatao.univ-toulouse.fr/9138/1/leon_partie_1_sur_2.pdf.
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Dans le but de réduire le bruit de jet, source principale de nuisance sonore au décollage d'un avion, une compréhension fine des mécanismes aéroacoustiques mis en jeu est nécessaire. Les structures cohérentes de grande échelle se développant dans la couche de mélange d'un jet semblent responsables d'une part importante du bruit observé en champ lointain, surtout dans les basses fréquences. Une approche permettant d'étudier ces structures turbulentes est fournie par la théorie de stabilité, notamment au moyen des équations de stabilité parabolisées (PSE). L'étude de ces ondes d'instabilité est alors complémentaire d'autres approches (LES ou expériences), puisqu'elle permet de mettre en évidence la nature et la dynamique de ces structures, également présentes dans les résultats de simulations ou de mesures.
Au cours de ces travaux de thèse, nous nous sommes intéressés aux structures cohérentes se développant dans des jets à double flux étudiés au cours du projet européen CoJeN (Coaxial Jet Noise). En particulier, nous avons exploité une base de données issues de mesures de fluctuations de pression réalisées en champ proche et en champ lointain de ces jets. Nous avons alors pu comparer les résultats de notre modélisation PSE à ces mesures en périphérie immédiate du jet, confirmant ainsi la pertinence d’un tel modèle, même dans des configurations aussi complexes. De plus, le calcul du rayonnement acoustique en champ lointain engendré par les fluctuations de pression modélisées nous a permis de faire des comparaisons directes avec les niveaux et les directivités mesurés. Nous avons ainsi pu mettre en évidence quantitativement la contribution de ces structures turbulentes de grande échelle au bruit total rayonné par le jet.
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Al-Kanaan, Adnan Jabbar Jadoa [Verfasser]. "Heat stress response for physiological traits in dairy and dual purpose cattle populations on phenotypic and genetic scales / Adnan Jabbar Jadoa Al-Kanaan." Kassel : Universitätsbibliothek Kassel, 2016. http://d-nb.info/1093437901/34.
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Abdel, Rahman Mahmoud Rania. "Toward the building of a local criteria of vascular lesion at the microscopical scale using homogenization." Strasbourg, 2010. https://publication-theses.unistra.fr/restreint/theses_doctorat/2010/ABDEL_RAHMAN_MAHMOUD_Rania_2010.pdf.
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Les hématomes sous–duraux aigus (HSDA) sont des agglomérations sanguins dans l’espace sous–dural. Ils sont généralement associés à la déchirure des veines ponts (VPs) provoquée par le mouvement relatif cerveau–crâne. Dans cette étude, on a essayé de développer un outil analytique pour être utilisé dans l’étude des HSDA causés par la déchirure des VPs. La technique d’homogénéisation par développement asymptotique a été appliquée, à l’échelle macro–méso, pour trouver les propriétés mécaniques effectives de la région d’interface cerveau–crâne. Ces propriétés sont ensuite intégrées dans un modèle par éléments finis de la tête humaine dans l’ordre d’obtenir le comportement mécanique global des éléments interfacials et la déformation des VPs. Le comportement mécanique dans le segment sous–arachnoïdien et le segment sous–dural de la veine a été aussi calculé. De plus, une approche d’homogénéisation de type inclusion, à l’échelle méso–micro, a été appliqué sur la paroi de la veine pour trouver les niveaux de contraintes et de déformations dans les fibres de collagène et la matrice d’élastine. Finalement un critère de rupture des VPs a été établi pour définir l’endroit exact de la déchirure des veines et les valeurs limites, en termes d’accélération rotatoire de la tête humaine, causant cette ruptureAcute subdural hematoma (ASDH) is a potentially devastating, yet curable extra axial fluid collection within the potential subdural space. It is classically associated with tearing of the bridging veins (BVs) caused by the brain–skull relative motion. In the current work, we tried to develop an analytical tool to be used in the prediction of ASDH arising from this type of lesion. The homogenization technique based on asymptotic expansion was applied, on the macro–meso scale, in order to find the effective mechanical properties of the brain–skull interface region. These properties were then incorporated into a finite element model of the human head to get the global stress–strain behavior in the elements of the interface region and the stretch strain in BVs. In addition, the mechanical behavior of the subarachnoid and subdural portions of the BV was investigated. Moreover, a meso–micro homogenization technique was applied on the BV wall to get the local mechanical behavior within the collagen fibers and the elastin matrix. Finally, a failure criterion for the BVs was developed defining the rupture location and the threshold of the rotational acceleration of the human head that cause the failure of the vein
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Prado, Claudia. "Ensino-aprendizagem da escala de coma de Glasgow: análise de duas técnicas em enfermeiros do serviço de emergência." Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/7/7135/tde-30032007-115512/.
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Partindo do princípio de que existe a necessidade de padronizar os enfermeiros quanto à avaliação do nível de consciência, em pacientes atendidos no Serviço de Emergência (SE), utilizando a Escala de Coma de Glasgow (ECGl), questiona-se quais as técnicas de ensino-aprendizagem mais adequadas. O presente estudo, limitado a medir a aquisição do conhecimento nessa temática, teve como objetivos analisar duas técnicas de ensino-aprendizagem, sendo uma a de exposição oral com slides e a outra, a leitura dirigida, em enfermeiros que atuam nos SE do município de São Paulo, divididos em dois grupos, com vistas a: caracterizá-los, segundo algumas variáveis sócio-demográficas, de aperfeiçoamento profissional e de utilização da ECGl; mensurar o grau de conhecimento, utilizando um teste de conhecimentos sobre a ECGl, antes de aplicar as duas técnicas; verificar o grau de aquisição de conhecimentos, utilizando o mesmo teste de conhecimentos, após a aplicação das duas técnicas. A coleta de dados foi feita com sorteio prévio dos hospitais selecionados quanto `a técnica a ser aplicada e realizada no final de 1999 e início de 2000. Os enfermeiros dos hospitais sorteados para serem submetidos à exposição oral compuseram o Grupo 1 e à leitura dirigida, o Grupo 2. Nas características dos dois grupos de enfermeiros, verificaram-se diferenças estatisticamente significativas nas variáveis idade, tempo de formado e utilização da ECGl. Os enfermeiros do Grupo 1 eram mais jovens, com faixa etária predominante entre 22 a 25 anos (45,5%), graduados há menos de 4 anos (72,7%) e a grande maioria relatou utilizar a ECGl, às vezes (72,7%). Contrariamente, os enfermeiros do Grupo 2 tinham mais de 31 anos (86,3%) e destes, 40,9%, mais que 41 anos; estavam mais distribuídos quanto ao tempo de formado, sendo que mais da metade tinham se graduado há mais de 5 anos; e, acima de um terço (36,4%) relatou nunca usar a ECGl e 40,9%, às vezes. Homogeneidade nas demais variáveis com preponderância do sexo feminino, e solteiros, graduação em escolas da Grande São Paulo e de tempo de experiência em SE menor que 5 anos e cursos de educação continuada variada e baixa, com exceção do Basic Life Support (BLS), freqüentado por 45,5% dos enfermeiros do Grupo 1. Na mensuração do grau de conhecimento prévio dos enfermeiros, constatou-se, na totalização de pontos, os dois Grupos alcançaram mais de 50% de acertos; aqueles do Grupo 1 totalizaram 273 (62,0%) pontos de acertos de um total de 440 pontos; os do Grupo 2 perfizeram 231 (52,5%) pontos. Em relação à aquisição de conhecimentos, após serem submetidos às duas técnicas de ensino-aprendizagem, verificou-se que o Grupo 1, no global, apresentou incremento estatisticamente significativo da fase pré para a pós do processo e ele foi de 29,8%; obteve altos percentuais de acertos, em várias questões, já na fase pré e incremento de conhecimentos estatisticamente significativo, também, na maioria das questões, principalmente naquelas de aplicação prática. O Grupo 2, embora no global tenha obtido incremento estatisticamente significativo da fase pré para a pós da ordem de 8,2%, ficou inconclusivo devido à ocorrência de um importante fator interveniente, caracterizado como não leitura do texto por parte de 55,0% dos participantes. Contudo, na análise por questão, pode-se constatar que o grupo apresentou acerto em menos da metade (41,0%) das questões, na fase pré, demonstrando a precariedade da base de conhecimentos deste Grupo e a necessidade de sanar essas lacunas. Embora os resultados obtidos apontem para a superioridade da técnica de exposição oral com slides em relação à leitura dirigida, incluindo maior adesão em participar, esta conclusão deve ser interpretada com restrição, visto que a leitura para atualização não demonstrou ser uma atividade do cotidiano desses enfermeirosConsidering the fact that there is the need to standardize nurses in relation to evaluating the level of consciousness in patients attended in emergency department (ED), by making use of the Glasgow Coma Scale (GCS), one questions which teaching-learning techniques are more adequate. The present study, limited to measuring the acquisition of knowledge regarding this topic, had the objective of analysing two teaching-learning techniques, one of them through lecturing with slides and the other one through guided reading, among nurses working in ED in the city of São Paulo. These nurses were subdivided into two groups aiming at: classifying them in relation to some variables such as their social-demographic status, professional improvement and use of GCS; measuring their level of previous knowledge by giving them a test about GCS, before applying both techniques; verifying the level of knowledge acquisition using the same test, after applying both techniques. Data collection was carried out with previously-selected hospitals drawn in relation to the technique to be applied; this data collection took place between the end of 1999 and beginning of 2000. Group 1 consisted of nurses from the drawn hospitals where lecturing with slides would be applied, whereas Group 2 was involved with guided reading. When analysing both groups of nurses statistically-significant differences in relation to age brackets, how long they had been graduated for and usage of GCS arose. Nurses in Group 1 were younger, mostly between 22 and 25 (45.5%), had been graduated for less than 4 years (72.7%) and in their great majority mentioned using GCS at times (72.7%). In contrast, nurses in Group 2 were over 31 years old (86.3%) and among these, 40.9% were over 41, had been graduated for a wider range of time (more than half for over a five-year´s time), and over one third (36.4%) of the nurses in this group mentioned never using GCS while 40.9% mentioned using it at times. The other variables were more homogeneous, with a predominance of female single nurses coming from schools in Greater São Paulo with an experience at ED of less than 5 years and a variedly-low attendance in continued education courses, except for Basic Life Support (BLS), frequented by 45.5% of the nurses in Group 1. When measuring nurses´level of previous knowledge, during the adding up of points, it was revealed that both groups scored higher than 50% of the correct answers; those in Group 1 reached 273 points (62%) out of 440; those in Group 2 obtained 231 points (52.5%). In relation to knowledge acquisition, after the application of both teaching-learning techniques, it was noticed that Group 1, as a whole, presented a statistically- significant improvement of 29.8% when comparing the fases before and after the process; this group also presented high rates of correct answers in several questions already during the pre-fase and a statistically-significant increase in knowledge as well in most questions, mainly in those related to practical application. Although Group 2 as a whole presented a statistically-significant increase (8.2%), when comparing the fases before and after the process, this group remained inconclusive due to an important intervening factor: 55% of its members did not read the texts. However, when analysing each question, it became clear that less than half of the questions (41%) were correctly answered by over 50% of the members in this group during the pre-fase, a fact which shows the precariousness of their previous knowledge and the need to bridge these gaps. Even though the results obtained in this research point out the superiority of lecturing with slides in relation to guided reading, including nurses higher interest in participating, this conclusion must be interpreted in terms since reading to update knowledge does not seem to be an everyday activity for these nurses
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Flores, Aviles Gabriela Patricia. "A groundwater basin multidisciplinary approach to conceptualize subsurface flow and trace nitrate contamination sources. Lake Titicaca, Bolivia." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAU019.
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La dégradation de la qualité de l'eau, la variabilité climatique et la croissance démographique font partie des facteurs limitant la disponibilité de l'eau dans les régions semi-arides de Katari et de Lago Menor (6,350 Km2), entraînant une exploitation croissante des ressources en eaux souterraines. Cette thèse a pour but de conceptualiser le système d'écoulement souterrain à grande échelle et de détecter les sources de contamination par les nitrates dans les régions de Katari et Lago Menor.Dans cette étude, on a utilisé une approche multidisciplinaire comprenant un inventaire régional des sources d’eaux souterraines et des mesures du niveau piézométrique, des techniques d’investigation géophysique (sondages électromagnétiques à domaine temporel TDEM), la construction et l’installation de piézomètres, l’analyse chimique des ions majeurs et les isotopes de 15N-NO3 et de 18O-NO3.Les résultats ont permis d'identifier les limites de deux contextes géologiques différents (le sous-système du Piémont et la plaine lacustre), la géométrie du milieu géologique poreux du Quaternaire et les limites inférieures de l'aquifère. L’analyse régionale montre que les flux souterrains suivent le modèle classique d’écoulement basé sur la gravité. Six sous-domaines ont été identifiés possédant des propriétés hydrauliques différentes. Une grande partie de l'aquifère présente un comportement non confiné, en particulier sur le Piémont, alors qu'il reste confiné dans les zones de plaine. L'épaisseur de la portion non confinée varie de 50 à 150 mètres. Les valeurs de conductivité hydraulique pour la portion non confinée vont de 1.1E-4 à 5.0E-6 m/sec, le rendement spécifique de 0,16 à 0,20 et les valeurs de recharge vont de 118 à 382 mm/year. Tandis que pour la partie confinée, les valeurs de transmissivité se situent autour de 6.0 E-6 m2/sec avec une valeur de stockage de 1.2E-2 à 6.0E-3.En particulier, dans les hautes régions du Piémont où se trouvent les fortes pressions hydrauliques, les compositions minérales, chimiques et isotopiques montrent que la source d'eau souterraine est de bonne qualité. En revanche, dans la partie inférieure du Piémont, les nappes phréatiques moins profondes de la séquence alluvial-fluvioglaciaire-lacustre rendent cette zone plus vulnérable à la contamination. En fait, le faciès chimique et la composition isotopique du NO3 dissous ont révélé que l'origine principale de cet anion est liée aux engrais azotés vers le nord-ouest du Piémont et aux déchets humaines / animales vers le SE. De plus, les processus naturels d'atténuation du nitrate se produisent principalement dans le secteur inférieur du Piémont, lorsque les eaux souterraines se mélangent au réservoir d'origine lacustre.En revanche, les eaux souterraines s'écoulant dans les plaines présentent principalement des faciès de Na (K) -Cl mettant en évidence la présence d'évaporites. Dans cette zone, les eaux souterraines sont sujettes à la contamination, en particulier lorsque la couche d'argile est absente et dans les endroits où une connexion au Piémont est mise en évidence (canaux souterrains). La contribution des eaux souterraines au lac Titicaca actuel (baie de Cohana) semble être retardée en raison de la présence de la couche d'argile.Ce modèle conceptuel d'écoulement des eaux souterraines permet une bonne compréhension du fonctionnement de l’aquifère et fournit un guide pour la collecte future de données afin d'améliorer la robustesse d’une future modélisation numérique des flux d’eau souterrains. Toutes les informations scientifiques issues de cette recherche ont été rassemblées dans une base de données spatiales SIG pour aider les décideurs à gérer et à protéger les ressources en eaux souterraines. Ces informations scientifiques contribuent également à l'assainissement de l'environnement du lac Titicaca, une priorité nationale de l'État plurinational de BolivieWater quality degradation, climate variability and population growth are among the factors that constrains water availability in the semi-arid Katari and Lago Menor region (6,350 Km^2), leading to an increasingly exploitation of groundwater resources. This thesis aims to conceptualize subsurface flow and trace nitrate contamination sources in the groundwater system within the Katari and Lago Menor Region.A multidisciplinary approach for field investigation was used in this study, including a regional groundwater source inventory and groundwater level measurements, geophysical investigation techniques (e.g. TDEM-Time Domain ElectroMagnetic soundings), piezometer construction and installation, and a regional sampling campaign and analysis for major ion chemistry and dual isotopes of 15N-NO3 and 18O-NO3.The results allowed identifying the limits of two different geological settings (Piedmont subsystem and Lacustrine plain), the geometry of the Quaternary porous geologic media and the bottom boundaries of the aquifer.The groundwater flow regime corresponds to a classical gravity-driven regional flow system. Six subdomains possessing different hydraulic properties were identified. A large portion of the aquifer presents an unconfined behaviour, particularly on the Piedmont, whereas it remains confined in the plain areas. The thickness of the unconfined portion varies from 50 to 150 meters. Values of hydraulic conductivity for the unconfined portion range from 1.1E-04 to 5.9E-08 m/sec, specific yield ranges from 0.16 to 0.20 and recharge values range from 118 to 382 mm/year. While for the confined part the transmissivity values range around 6.0E-06 m^2/sec with a storavity value of 1.2E-02 to 6.0E-03.In the high Piedmont areas where the hydraulic heads are high, the low mineralization and the chemical and isotopic compositions showed that the groundwater source is of good quality. In contrast, in the lower sector of the Piedmont, the shallower water tables of the alluvial-fluvioglacial-lacustrine sequence, make this area more vulnerable to contamination. Chemical facies and the isotopic composition of the dissolved NO3 revealed that the main origin of this anion is related to nitrogen fertilizers towards the NW of the Piedmont and human/animal waste towards the SE. Moreover, natural nitrate attenuation processes occur mainly in the lower sector of the Piedmont, when groundwater mixes with the reservoir of lacustrine origin. Groundwater flowing in the plain areas, present primarily Na(K)-Cl facies relating the presence of evaporites. In this area groundwater is prone to contamination, especially when the clay layer is absent and in places where a connection to the Piedmont is evidenced (subterranean channels). The contribution of groundwater to the current Lake Titicaca (Cohana Bay) appears to be retarded due to the presence of the clay layer.This basin-scale conceptual groundwater flow model provides a good understanding of the aquifer functioning, and a guide to future data collection, in order to improve the robustness of future groundwater flow numerical modeling. All the science-based information generated from this research was arranged into a GIS spatial database to support decision makers in the management and protection of groundwater resources. This science-based information also contributes to the environmental remediation of Lake Titicaca, a national priority for the Plurinational State of Bolivia
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Santini, Manuela Favarin. "Comparação entre duas associações de analgésicos não opioides e opioides no controle da dor do abscesso dentoalveolar agudo em evolução : um ensaio clínico randomizado." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/116478.
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Objetivos: Avaliar o manejo da dor em Endodontia por meio de dois estudos: Artigo 1 – um ensaio clínico randomizado comparando a eficácia analgésica de duas associações de opioide e não opioide no controle da dor do Abscesso Dentoalveolar Agudo (ADA) em evolução; Artigo 2 – uma revisão sistemática investigando a eficácia e segurança de terapia sistêmica para o tratamento da dor de origem endodôntica. Métodos: No Artigo 1, foram incluídos 24 pacientes que procuraram atendimento em serviço odontológico universitário do sul do Brasil. Após o atendimento de urgência, os pacientes foram alocados em dois grupos: Co/Pa – prescrição da associação de codeína (30 mg) e paracetamol (500 mg), por via oral, a cada 4 h, por 3 dias; Tr/Pa - prescrição da associação de cloridrato de tramadol (37,5 mg) e paracetamol (500 mg), na mesma posologia do grupo anterior. Os escores de dor foram registrados pelo próprio paciente, nos tempos 6, 12, 24, 48 e 72 h após o atendimento, em diário específico de evolução da dor, por meio da Escala Analógica Visual (EAV). No Artigo 2, foi realizada uma revisão sistemática, por meio de buscas conduzidas nas bases de dados: MEDLINE, registro de ensaios clínicos da Cochrane Library, LILACS, SciELO, banco de teses/dissertações da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) e referências dos artigos encontrados. Para serem incluídos, os artigos deveriam ser ensaios clínicos randomizados (ECRs), controlados e cegos, ou revisões sistemáticas com ou sem metanálise. Deveriam ter um dos braços de terapia constituído por analgésico ou anti-inflamatório, administrado por via oral, para controle da dor moderada a intensa, de origem endodôntica, mensurada por meio da Escala Analógica Visual, em adultos. Foram coletados dados referentes às características da amostra, escores de dor pré-tratamento, características dos grupos em comparação, aspectos de qualidade metodológica, frequência de uso de analgésico adicional e a frequência de eventos adversos. Foram realizadas análises descritiva e inferencial. Resultados: No Artigo 1, em ambos os grupos, houve redução dos escores de dor ao longo do tempo. No grupo Co/Pa, houve redução significativa dos escores em 12, 24, 48 e 72 horas, em comparação com aos iniciais (P<0,05). Os escores em 48 e 72 horas foram menores, em relação aos iniciais e aos escores das 6 horas (P<0,05). No grupo Tr/Pa, houve redução dos escores de todos os tempos experimentais, em relação aos iniciais (P<0,05). Para todos os intervalos de tempo analisados, os grupos não foram diferentes entre si (P>0,05). Ambos os tratamentos foram eficazes no controle da dor provocada pelo ADA em evolução. Porém, a associação Tr/Pa apresentou-se menos segura. No Artigo 2, de um total de 431 referências, 419 resumos foram analisados e 14 artigos foram lidos na íntegra. Após a exclusão de 5 artigos, 9 ensaios clínicos preencheram os critérios de inclusão. Os estudos compararam paracetamol, AINE (ibuprofeno, flurbiprofeno, cetorolaco de trometamina, etodolaco, tenoxicam), prednisolona, tramadol e associações analgésicas no tratamento da dor endodôntica moderada a intensa. Foi observado que os medicamentos foram administrados antes ou após a intervenção endodôntica. Em 8 estudos, o grupo controle foi placebo e 8 estudos utilizaram o esquema de dose única para avaliar o controle da dor. Em todos os ensaios clínicos, o desfecho primário analisado foi a redução dos escores de dor e os desfechos secundários, uso de medicamento adicional e ocorrência de reações adversas. Foi possível estabelecer uma relação significativa entre uso de analgésico adicional e diagnóstico periapical. Quando a administração ocorreu antes do procedimento endodôntico, não foi observada a ocorrência de eventos adversos. Quando a administração ocorreu após o procedimento, foram relatadas reações adversas em dois dos três estudos incluídos na análise. Conclusão: O Artigo 1 sugere que, em função de eficácia analgésica e segurança, a associação codeína/paracetamol seja mais efetiva para o controle da dor aguda de moderada a intensa, no tratamento da ADA em evolução. O Artigo 2 aponta carência de ECRs em Endodontia, que utilizem um mesmo padrão metodológico, para definição de um protocolo de tratamento sistêmico na dor de origem endodôntica.Aim: To evaluate the management of pain in Endodontics by two studies: Article 1 - a randomized clinical trial comparing the analgesic efficacy of two opioids and non-opioid associations in the pain control of Acute Dentoalveolar Abscess (ADA); Article 2 - a systematic review investigating the efficacy and safety of analgesic therapy in the management endodontic pain.Methodology: The Article 1 included 24 patients that looked for emergency treatment in a university dental clinic. These patients were divided into two groups: Co / Pa - prescription of codeine (30 mg) + acetaminophen (500 mg) oral, every 4 h, during 3 days; Tr / Ac - prescription of tramadol hydrochloride (37.5 mg) + acetaminophen (500 mg) as the previous group. Pain scores were recorded by the patient at 6, 12, 24, 48, and 72 h after treatment, in a pain diary, using the Visual Analogue Scale (VAS). The Article 2 was conducted in electronic databases, gray literature, and references of retrieved articles to analyze randomized clinical trials or systematic reviews with or without meta-analysis. One arms of the therapy should have comprised an anti-inflammatory or analgesic drugs, orally administered by adults, in order to control moderate to severe pain, measured by Visual Analogue Scale, cause by endodontic problems . Data were collected regarding the characteristics of the sample, scores of pretreatment pain, characteristics of compared groups, methodological quality aspects, additional analgesic use, and frequency of adverse events. Descriptive and inferential analyzes were performed. Results: In Article 1, in both groups there was a reduction in the pain scores over time. For Co/Ac group, it was found a significant reduction in the scores at 12, 24, 48, and 72 hours after treatment (P <0.05). The scores at 48 and 72 hours were lower, compared to immediate treatment and scores at 6 hours after treatment (P <0.05). In the Tr/ Ac group, the scores decreased as the time is increasing (P <0.05). For all time intervals tested, the groups were not significantly different (P> 0.05). Both treatments were effective in controlling pain caused by ADA. The association Tr/ Ac presented itself less secure. In Article 2, a total of 431 references and 419 abstracts were reviewed, then only 14 articles were read in full. From these articles it was excluded 5 and 9 trials met the inclusion criteria. These studies compared acetaminophen, NSAIDs (ibuprofen, flurbiprofen, ketorolac tromethamine, etodolac, and tenoxicam), prednisolone, and analgesic tramadol associations for treating moderate to severe endodontic pain. It was observed that drugs were administered before or after endodontic therapy. In 8 studies, the control group was placebo and 8 studies used single dose regimen to assess pain control. In all clinical trials, the primary outcome analyzed was the reduction of scores in pain and secondary outcomes were the utilization of additional medication and adverse reactions. It was possible to establish a significant relationship between use of additional analgesics and periapical diagnosis. When the administration occurred before the endodontic procedure no adverse events were observed. When it was administered after the procedure, adverse reactions were reported in 2 of 3 trials included in the analysis. Conclusion: The Article 1 suggests that, considering analgesic efficacy and safety function, the association codeine/ acetaminophen is more effective for the control moderate to severe pain, at the treatment of ADA in evolution. The Article 2 found that there is a lack of RCTs in Endodontics using the same methodological standard to define a systemic treatment protocol of endodontic pain.
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Campos, Marcio José da Silva. "Estudo da experiência de dor e do status imunológico em adultos e crianças durante duas fases do tratamento ortodôntico." Universidade Federal de Juiz de Fora (UFJF), 2010. https://repositorio.ufjf.br/jspui/handle/ufjf/3895.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
A Dor é comumente relatada durante o tratamento ortodôntico, sendo proveniente da força aplicada aos dentes e de lesões traumáticas na mucosa bucal, onde a Imunoglobulina A secretora (sIgA) é a principal proteção e pode participar na manutenção da sua integridade. A dor pode aumentar o estresse psicológico, que relaciona-se com a alfa-amilase salivar. A intensidade da dor pode variar segundo a idade do paciente e sua motivação ao tratamento. O objetivo foi avaliar a intensidade de dor e sua relação com a motivação dos pacientes e com as concentrações salivares de sIgA e alfa-amilase, em adultos e crianças durante duas fases do tratamento ortodôntico. Vinte indivíduos (10 crianças e 10 adultos) responderam à um questionário de avaliação da motivação ao tratamento. Amostras de saliva foram coletadas e a intensidade de dor foi registrada diariamente, antes e após a colagem dos bráquetes e após a inserção do arco inicial. Apenas uma questão, relacionada à percepção da severidade da má oclusão, apresentou correlação com a intensidade de dor. Não houve diferença significante na intensidade de dor e na concentração sIgA entre adultos e crianças. De modo geral as crianças exibiram menor prevalência de dor, porém com maior intensidade. Houve uma tendência de correlação negativa entre a dor na mucosa bucal e a concentração de sIgA nas crianças, o que pode indicar a importância da sIgA na proteção da mucosa bucal. A concentração de alfa-amilase não teve correlação significante com a intensidade de dor, porém apresentou um aumento progressivo durante o período de avaliação, provavelmente devido ao estresse psicológico causado pela presença e ativação do aparelho fixo.
Pain is usually reported during orthodontic treatment. It comes from the strength applied to the teeth and traumatic lesions in the buccal mucosa, where secretory immunoglobulin A (sIgA) is the main protection and plays a role in integrity maintenance. Pain can increase the psychological stress, which induces changes in salivary alpha amylase. Pain intensity can vary according to patient’s age and his/her motivation towards treatment. The aim of this study was to evaluate pain intensity and its relation with patient’s motivation and salivary levels of slgA and alpha amylase, in adults and children, during two stages of orthodontic treatment. Twenty individuals (10 children and 10 adults) answered a questionnaire regarding their motivation towards treatment. Saliva samples were collected and pain intensity was evaluated on a daily basis, after and before the bonding of brackets and after the insertion of the initial arch. Only one question regarding the perception of malocclusion severity correlated with pain intensity. There was no significant difference in pain intensity and in slgA concentrations between adults and children. In general, pain prevalence in children was lower, yet reported pain was more intense. Pain in the buccal mucosa was negatively correlated with slgA concentrations in children, a finding that suggests a protective effect of slgA in the buccal mucosa. Although there was no significant correlation between the concentrations of alpha amylase and pain intensity, the levels of this enzyme increased during the evaluation period, probably due to the psychological stress caused by the presence and activation of the fixed braces.
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Poveda, Claudia Ligia Esperanza Charry. "Análise da validade, interpretação e preferência da versão brasileira da Escala Facial de Dor - Revisada, em duas amostras clínicas." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/59/59134/tde-03052012-111521/.
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A Escala Facial de Dor - Revisada (EFD-R) é uma das escalas mais recomendadas na mensuração da intensidade da dor aguda em crianças. A versão original desta escala foi testada em crianças canadenses. O objetivo deste trabalho foi avaliar a validade, interpretação e preferência da versão brasileira da Escala Facial de Dor - Revisada (EFD-R-B), em duas amostras de crianças brasileiras: uma envolvendo dor aguda procedural e outra dor aguda pós-cirúrgica. Na primeira amostra participaram 77 crianças com idades entre 6 e 12 anos, do sexo feminino e masculino, que foram submetidas à coleta de sangue (dor procedural). As crianças estimaram a intensidade da sua dor, antes e após a punção venosa, na EFD-R-B. Na estimação após a punção venosa, a Escala Colorida Analógica (ECA) foi administrada junto com a EFD-R-B e, além disso, as crianças indicaram as faces que expressavam uma dor leve, moderada e severa, a escala que preferiam e o porquê. Na segunda amostra, participaram 53 crianças com idades entre 6 e 12 anos, do sexo feminino e masculino, que tinham sido submetidas a pequenas cirurgias (dor pós-cirúrgica). Nesta amostra, as crianças estimaram, na EFD-R-B e na ECA, a intensidade da dor que estavam sentindo no momento da entrevista. Também indicaram as faces que expressavam uma dor leve, moderada e severa, o limiar de tratamento da dor, a escala que preferiam e o porquê. Na comparação entre as pontuações obtidas na EFD-R-B e na ECA (validade convergente), nas duas amostras, os valores dos coeficientes Kendall\'s tau foram altos e significativos: =0,75 para o grupo de dor procedural e =0,79 para o grupo de dor pós-cirúrgica (p=0,00 nas duas amostras). No grupo de dor procedural, a EFD-R-B refletiu as mudanças na intensidade da dor vivenciada pelas crianças antes e após a punção venosa (validade concorrente): Teste de Wilcoxon z=-6,65; p=0,00. Considerando uma escala de 0 a 10 para a EFD-R-B, a mediana e a amplitude interquartil (AIQ) para as faces indicadas como expressivas de intensidade leve, moderada e severa, foram 2 (2-2), 4 (4-6) e 10 (10-10) respectivamente, no grupo de dor procedural, e 2 (2-2), 6 (4-8) e 10 (10-10) respectivamente, no grupo de dor pós-cirúrgica. Na estimação do limiar de tratamento da dor (grupo de dor pós-cirúrgica), a mediana (AIQ) foi 6 (4-10). No grupo de dor procedural, a EFD-R-B foi a escala preferida por 57,1% das crianças e a ECA por 41,6%; no grupo de dor pós-cirúrgica, a EFD-R-B foi escolhida por 66% das crianças e a ECA por 34%. Estas proporções somente foram significativas no grupo de dor pós-cirúrgica (X²=5,453 p=0,02). Nossos resultados mostram que a EFD-R-B possui propriedades similares à escala original e boa aceitação entre as crianças entrevistadas. A determinação dos valores das diferentes intensidades de dor e do limiar de tratamento da dor, para cada participante, representa uma evidência importante sobre a interpretação da EFD-R.The Faces Pain Scale Revised (FPS-R) is one of the most recommended tools in measuring the intensity of acute pain in children. The aim of this study was to assess validity, interpretability and preference of the Brazilian version of the FPS-R (FPS-R-B), in two different clinical samples. The first sample contained seventy-seven children, 6 to 12 years old and both sexes, undergoing venipuncture for blood sample (procedural pain). These children estimated their perceived pain intensity in FPS-R-B before and after venipuncture. Furthermore, after venipuncture, children were asked: a) to evaluate the intensity of their needle pain using the Coloured Analogue Scale (CAS), b) to indicate on the Faces scale the intensities representing the mild, moderate and severe pain, and c) to choose the scale they preferred and indicate the reasons for the preference. The second sample included fifty-three children, 6 to 12 years old and both sexes, undergoing minor surgery (postoperative pain). Following surgery, children were asked: a) to provide a rating of their current pain intensity using the FPS-R-B and the CAS, b) to indicate on the Faces scale the intensities representing the mild, moderate and severe pain, c) to estimate, on the FPS-R-B, the intensity of pain that their felt to warrant pharmacologic intervention (pain treatment threshold), and d) to choose the scale they preferred and indicate the reasons for the preference. The degree of concordance between FPS-R-B and CAS ratings (convergent validity), for both samples, was high and statistically significant Kendall\'s tau value was 0.75 for the first sample, and 0.79 for the second sample, (p<0.05) . FPS-R-B reflected the changes in pain intensity before and after venipuncture (concurrent validity): Wilcoxon Test z=- 6.24; p< 0.05. On the 0-10 scale for the FPS-R-B, the median and interquartile range (IQR) of the intensities that represented mild, moderate and severe pain were 2 (2-2), 4 (4-6) e 10 (10-10) respectively, for the first sample, and 2 (2-2), 6 (4-8) e 10 (10-10) respectively, for the second sample. The median and IQR for pain treatment threshold were 6 (4-10). Fifty-seven percent of children in the first sample and 64.8% in the second sample preferred the FPS-R-B. These proportions were statistically significant for the second sample (X²=5,453 p<0,05). Our data show that the FPS-R-B has similar statistical properties to the original. New evidences were presented regarding interpretability of the FPS-R by determining each children\'s treatment threshold and estimate of mild, moderate and severe pain. In this study, the FPS-R-B was preferred by the majority of children.
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Duan, Xiaohong [Verfasser], Jean Charles [Akademischer Betreuer] Munch, and Eckart [Akademischer Betreuer] Priesack. "Modeling the impact of soil heterogeneity on the variability of crop growth at field scale / Xiaohong Duan. Gutachter: Jean Charles Munch ; Eckart Priesack. Betreuer: Jean Charles Munch." München : Universitätsbibliothek der TU München, 2011. http://d-nb.info/1015804721/34.
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