Search results for "ground"

Size-consistent single-reference methods for electronic correlation: a unified formulation through intermediate hamiltonian theory

1996

Using the intermediate hamiltonian theory as a unique conceptual frame and the technique of CI matrix dressing, a wide series of single-reference methods for the treatment of the ground state correlation are reviewed, compared, and sometimes improved. These methods range from independent excitation approximation (the very next step beyond MP2) to coupled cluster, going through the so-called electron pair approximations and the (SC)2CI formalism. A hierarchy of these methods can be established according to two criteria: These formulations in terms of diagonalizations of dressed CI matrices avoid convergence problems, but their main advantage is their flexibility, since they apply to multi-re…

The VN2 negatively charged defect in diamond. A quantum mechanical investigation of the EPR response

2020

Abstract The VN 2 − defect in diamond consists of a vacancy surrounded by two substitutional nitrogen atoms, which lower the local symmetry from Td to C2v. Calculations of the doublet ground state geometry, electronic structure, EPR parameters, and IR spectra of this defect are reported along with a preliminary investigation of the observed optical transition. For the most part our results were obtained using a uniform charge compensated supercell approach together with the B3LYP functional and all-electron Gaussian basis sets designed for the properties studied. In particular, the computed hyperfine and quadrupolar EPR parameters for the carbon and nitrogen atoms adjacent to the vacancy ag…

"Aika vaatii attentaatteja kaikkia vastaan" : elonkorjaajat, Leo Lindsten ja Markus Heikkerö 1960- ja 1970-lukujen vaihteen suomalaisessa kuvataideke…

1999

Embodiment e percezione dello spazio alle origini della cultura indoeuropea

2018

La costruzione dell’identità scaturisce dall’esperienza corporea e dalla sua concreta rappresentazione nello spazio. Lo studio degli universali del linguaggio in relazione ai sistemi di coordinate spaziali utilizzati nelle lingue del mondo ha recentemente attirato l'attenzione della ricerca nell’ambito non solo linguistico, ma anche delle neuroscienze (Diessel 2013: 687; Kemmerer 2010). In particolare, la letteratura esistente sulla tipologia delle espressioni spaziali è tradizionalmente basata sull’assunto che il sistema di riferimento deittico o egocentrico in uso nelle lingue europee moderne costituisca un universale linguistico e culturale. Anche la tradizione filosofica, da Kant (1768)…

Maternal teaching of reading and children's reading skills in Grade 1: Patterns and predictors of positive and negative associations

2013

Abstract The main aim of the study was to identify subgroups of children based on the associations between the reported frequency of maternal teaching of reading and children's reading skills, and whether these subgroups differ with respect to mother-related (i.e., education, controlling behavior, and emotions in homework situations) and child-related (i.e., reading habits and gender) background factors. Data were gathered from 1460 mother–child dyads. The reading skills of 6- to 7-year-old Finnish-speaking children were measured at the beginning and at the end of Grade 1. Information from mothers was gathered by questionnaires. Regression Mixture Modeling identified four latent subgroups o…

Early-stage thermal performance design of thermo-active walls implemented in underground infrastructures

2022

Abstract Energy geostructures (EGs) represent an innovative technology in the sustainable energy agenda and are useful for satisfying the energy needs of the built environment. They are usually involving geostructures such as piles, walls, tunnels, shafts, and sewers. The application of such technology to infrastructure projects may have considerable thermal potential because of the large surfaces that can be thermally activated. This study focuses on thermo-active walls (energy walls, EWs), which are retaining structures used to sustain the sides of excavations. Key features related to their thermal design are examined, and a design methodology is proposed. The heat-exchange modes involvin…

Experimental analysis of a thermoactive underground railway station

2022

Little is known about the real energy potential of thermoactive underground infrastructures, such as railway stations, that can act as a heating/cooling provider for the built environment. This study presents the results of thermomechanical full-scale in situ testing and numerical analysis of a thermoactive underground train station. The thermal performance and related geostructural impact of a portion of the new underground energy infrastructure (UEI) installed at the Lancy-Bachet train station in Geneva (Switzerland) are analyzed. Heating and cooling tests simulating real operative geothermal conditions are considered. Particular attention is given to ((i) the monitored wall-tunnel hydrot…

Increasing understanding and confidence in THM simulations of engineered barrier systems

2020

Previous studies on the modelling of coupled thermo-hydro-mechanical (THM) processes in bentonite-based engineered barrier systems (EBSs) showed the sensitivity of the output quantities to changes in the input parameters. To investigate the effects of uncertainties on the modelling results, to improve the understanding of the coupled processes active in the repository near field and to gain in-depth understanding of model uncertainties of different codes, a sensitivity analysis and code comparison of EBS simulations was performed within the Task Force on Engineered Barrier Systems. The analysis included variations in material parameter values, boundary and initial conditions, considered phy…

Motion Control of Four-Wheel Independently Actuated Electric Ground Vehicles considering Tire Force Saturations

2013

A vehicle stability control approach for four-wheel independently actuated (FWIA) electric vehicles is presented. The proposed control method consists of a higher-level controller and a lower-level controller. An adaptive control-based higher-level controller is designed to yield the vehicle virtual control efforts to track the desired vehicle motions due to the possible modeling inaccuracies and parametric uncertainties. The lower-level controller considering tire force saturation is given to allocate the required control efforts to the four in-wheel motors for providing the desired tire forces. An analytic method is given to distribute the high-level control efforts, without using the num…

Take-off aerodynamics in ski jumping

2001

The effect of aerodynamic forces on the force-time characteristics of the simulated ski jumping take-off was examined in a wind tunnel. Vertical and horizontal ground reaction forces were recorded with a force plate installed under the wind tunnel floor. The jumpers performed take-offs in non-wind conditions and in various wind conditions (21-33 m s(-1)). EMGs of the important take-off muscles were recorded from one jumper. The dramatic decrease in take-off time found in all jumpers can be considered as the result of the influence of aerodynamic lift. The loss in impulse due to the shorter force production time with the same take-off force is compensated with the increase in lift force, res…