Search results for "Aalto"

Alvar Aallon Jyväskylän poliisitalo

2000

Idea kotilon kuoressa : Alvar Aallon kampuskappelisuunnitelman muotoutuminen

2023

Artikkelissa tarkastellaan kampuskappelisuunnitelmaa, jonka Jyväskylän kasvatusopillisen korkeakoulun ylioppilaskunta tilasi arkkitehti Alvar Aallolta (1898–1976) vuonna 1961. Kappeli oli tarkoitus rakentaa vuoden 1964 lopulla valmistuneen ylioppilastalon osaksi. Kyseessä on taidehistoriallinen tapaustutkimus, erityisesti eri prosessivaiheista muodostuvan suunnittelukokonaisuuden selvitys. Artikkelissa tarkastellaan Aallon toimiston laatimia neljänlaisia luonnoksia kiinnittäen huomiota kappelin sijaintiin, muotoon, ja sisätilaratkaisuihin. Tutkimus osoittaa, miten määrätietoisesti Alvar Aalto piti kiinni arkkitehtonisen ja kaupunkikuvallisen näkemyksensä säilymisestä projektin edetessä. Kap…

Coded excitation speeds up the detection of the fundamental flexural guided wave in coated tubes

2016

The fundamental flexural guided wave (FFGW) permits ultrasonic assessment of the wall thickness of solid waveguides, such as tubes or, e.g., long cortical bones. Recently, an optical non-contact method was proposed for ultrasound excitation and detection with the aim of facilitating the FFGW reception by suppressing the interfering modes from the soft coating. This technique suffers from low SNR and requires iterative physical scanning across the source-receiver distance for 2D-FFT analysis. This means that SNR improvement achieved by temporal averaging becomes time-consuming (several minutes) which reduces the applicability of the technique, especially in time-critical applications such as…

Higher-order Hamilton–Jacobi perturbation theory for anisotropic heterogeneous media: dynamic ray tracing in Cartesian coordinates

2018

With a Hamilton–Jacobi equation in Cartesian coordinates as a starting point, it is common to use a system of ordinary differential equations describing the continuation of first-order derivatives of phase-space perturbations along a reference ray. Such derivatives can be exploited for calculating geometrical spreading on the reference ray and for establishing a framework for second-order extrapolation of traveltime to points outside the reference ray. The continuation of first-order derivatives of phase-space perturbations has historically been referred to as dynamic ray tracing. The reason for this is its importance in the process of calculating amplitudes along the reference ray. We exte…

Experiencing Authenticity at Alvar Aalto’s Experimental House

2021

Experiences of authenticity are studied at Alvar Aalto’s Experimental House – today a modern house museum – which has gone through renovations and changes. Visitors were interviewed to find out how they feel about the authenticity of the place, if the changes affect their experience of authenticity, and if they share the same opinions. A review of the literature on the concept of authenticity is carried out and its implications for museum contexts is considered, and then the research questions are answered by analysing 30 interviews of visitors to the Experimental House.

Elektroniset aaltopaketit atomeissa ja pienissä molekyyleissä

2005

Discrete exterior calculus for photonic crystal waveguides

2022

The discrete exterior calculus (DEC) is very promising, though not yet widely used, discretization method for photonic crystal (PC) waveguides. It can be seen as a generalization of the finite difference time domain (FDTD) method. The DEC enables efficient time evolution by construction and fits well for nonhomogeneous computational domains and obstacles of curved surfaces. These properties are typically present in applications of PC waveguides that are constructed as periodic structures of inhomogeneities in a computational domain. We present a two-dimensional DEC discretization for PC waveguides and demonstrate it with a selection of numerical experiments typical in the application area. …

Multiobjective muffler shape optimization with hybrid acoustics modelling

2010

Shape optimization of a duct system with respect to sound transmission loss is considered. The objective of optimization is to maximize the sound transmission loss at multiple frequency ranges simultaneously by adjusting the shape of a reactive muffler component. The noise reduction problem is formulated as a multiobjective optimization problem. The sound attenuation for each considered frequency is determined by a hybrid method, which requires solving Helmholtz equation numerically by finite element method. The optimization is performed using non-dominated sorting genetic algorithm, NSGA-II, which is a multi-objective genetic algorithm. The hybrid numerical method is flexible with respect …

Äänenvaimentimien mallinnuspohjainen monitavotteinen muodonoptimointi

2011

Multiobjective muffler shape optimization with hybrid acoustics modelling

2011

This paper considers the combined use of a hybrid numerical method for the modeling of acoustic mufflers and a genetic algorithm for multiobjective optimization. The hybrid numerical method provides accurate modeling of sound propagation in uniform waveguides with non-uniform obstructions. It is based on coupling a wave based modal solution in the uniform sections of the waveguide to a finite element solution in the non-uniform component. Finite element method provides flexible modeling of complicated geometries, varying material parameters, and boundary conditions, while the wave based solution leads to accurate treatment of non-reflecting boundaries and straightforward computation of the …