Search results for "mathematical model."
showing 10 items of 343 documents
Regional Economics Tools applied to Sport: New Perspectives
2007
This article shows how some regional economics tools, which are not very well known, can be used in the field of sport. The first part consists of a short summary of the location analysis models. In a second part, we show on a case study, that computable location models can be used to determine the optimal location of sporting facilities in the context of intercommunity. To conclude, some extensions are suggested from a theoretical point of view as well as for empirical applications.
The Experimental Validation of a New Thermodynamic Method for TDC Determination
2007
In-cylinder pressure analysis is becoming more and more important both for research and development purpose and for control and diagnosis of internal combustion engines; directly measured by means of a combustion chamber pressure transducers or evaluated by analysing instantaneous engine speed [1,2,3,4], incylinder pressure allows the evaluation of indicated mean effective pressure (IMEP), combustion heat release, combustion phase, friction pressure, etc...It is well known to internal combustion engine researchers that for a right evaluation of these quantities the exact determination of Top Dead Centre (TDC) is of vital importance: a 1° error on TDC determination can lead to evaluation err…
Elastoplastic Damaging Model for Adhesive Anchor Systems. I: Theoretical Formulation and Numerical Implementation
2011
In this and in the companion paper, the mechanical response of adhesive anchor systems is theoretically and numerically predicted and experimentally observed. The theoretical prediction is on the basis of an elastoplastic damaging model formulated to predict the structural response associated with the development of a fracture in adhesive anchor systems. This part describes the analytical model developed in the framework of a thermodynamically consistent theory, which assumes adhesion where the structure is sound, and friction in correspondence with the fracture. Isotropic damage is considered. The model can predict the structural behavior at the interface between two surfaces of ductile, b…
Mathematical modelling of the industrial growth of large silicon crystals by CZ and FZ process
2003
The present paper gives an overview of the complex mathematical modelling of industrial Czochralski (CZ) and floating‐zone (FZ) processes for the growth of large silicon single crystals from melt. Extensive numerical investigations of turbulent Si‐melt flows in large diameter CZ crucibles, global thermal calculations in growth facilities and analysis of the influence of various electromagnetic fields on CZ process are presented. For FZ process, a complex system of coupled 2D and 3D mathematical models is presented to show the possibilities of modelling from the calculation of the molten zone shape till the resistivity distribution in the grown crystal. A special developed program code is pr…
Modeling of Magnetic-Field-Assisted Fluidization: Model Development and CFD Simulation of Magnetically Stabilized Fluidized Beds
2014
Magnetic-field-assisted fluidization is starting to be considered as a viable alternative to standard fluidized beds for those operations (such as particle separations, filtration, adsorption) in which the solid phase can be made of magnetic particles or, alternatively, the fluidizing agent is a ferro-fluid; thus the fluid bed responds to the action of magnetic fields, and stabilized fluidization regimes can be generated. One of the major difficulties to be tackled is the development of a predictive model capable of estimating the stabilized-to-bubbling transition velocity for a given magnetic field or, on the other hand, the magnetic field intensity required to stabilize the bed to a quies…
Diffusion Measurements on Crystalline Rock Matrix
1994
AbstractA new gas flow technique is introduced such that experiments on very long samples are possible. This new technique together with increased accuracy of the measurements, allows the observation of power law tails in the break-through curves. Dispersion in these experiments can be controlled in great detail, and therefore the power law tails can be used to determine very accurately the parameters relevant in matrix diffusion. Results for rock and metal samples are shown, and they are fitted with model calculations which include both dispersion and matrix diffusion. The introduced technique, which is designed for ordinary drill cores, is suitable for scanning a large number of samples i…
Creep–recovery and oscillatory rheology of flour-based systems
2023
The chapter reviews the application of creep-recovery and oscillatory rheological tests in flour based systems, including simple flour water systems, and more complex ones, such as bread, cookies and biscuits. A theoretical introduction about the fundaments and methods of linear viscoelastic rheology is presented, including general mathematical models and their application in flour based systems. A summary of experimental conditions to perform the rheological tests is covered. Functionality of flour based systems is extremely dependent on their viscoelastic properties. Processes like mixing, pumping, lamination, baking performance have been found to be strongly dependent on the system visco…
The effect of wear on the tetragonal-to-monoclinic transformation and the residual stress distribution in zirconia-toughened alumina cutting tools
1998
Abstract Zirconia-toughened alumina cutting tools have been examined after machining an AISI 1040 steel. The Raman spectrum of zirconia and the fluorescence spectrum from alumina have been used to determine the extent of the tetragonal-to-monoclinic (t-m) transformation and the residual stresses in and around the worn-out crater, respectively. Although about 15% vol. m-zirconia is present even in a brand new cutting tool, it was shown that the crater region undergoes the t-m transformation up to 40% vol. In both cases, the transformed zone is concentrated near the surface. The residual stresses in alumina are slightly compressive in the new cutting tool and away from the crater region, but …
The Influence of Surface Roughness on the Structure of Magnetohydrodynamic Flows and Stability of Shallow Water Flows
2008
Promocijas darbā analizēta virsmas negluduma ietekme uz šķidruma plūsmas struktūru magnētiskā laukā un sekla ūdens plūsmas stabilitāti. Promocijas darbā tika aplūkoti šādi modeļi: 1) vadoša šķidruma plūsma ārējā magnētiskā laukā virs dažāda veida negluduma elementiem uz virsmas un 2) sekla ūdens plūsma aiz šķēršļiem. Turklāt ir iegūta magnētiskā lauka struktūra pilnīgi attīstītai plūsmai virs negluduma elementiem. Ir konstruēts analītisks atrisinājums uzdevumam par vadoša šķidruma plūsmu magnētiskā laukā, ja negluduma elementiem ir taisnstūrveida forma. Ir aprēķināti šķidruma plūsmas ātruma un inducētā magnētiskā lauka sadalījumi. Problēmas asimptotisks atrisinājums (elementārās funkcijās) …
Shallow flow stability analysis with applications in hydraulics
2016
Šķidruma plūsmas stabilitātes analīze ar pielietojumiem hidraulikā Promocijas darbā tiek veikta plūsmu l ineārā un vāji nelineārā stabilitātes analīze seklos sajaukšanās slāņos. Plūsma tiek pieņemta kā nedaudz izliekta garenvirzienā . Berzes koe ficients mainās šķērsvirzienā . Lineārā stabilitāte tiek analizēta no laika un telpas aspektiem. Turklāt problēma ir vispārināta divu komponenšu seklām plūsmām. Tiek izskatītas divas pieejas vāji nelineārās stabilitātes analīzei. Parādīts, ka amplitūdas vie nādojums ir kompleksais Ginzburga - Landau vienādojums (paralēlu plūsmu pieņēmums). Otra pieeja ņem vērā lēno garenvirziena bāzes plūsmas izmaiņ u . Tiek iegū ts pirmās kārtas amplitūdas attīstīb…