Search results for " method"
showing 10 items of 10455 documents
Biodynamic behavior of the trunk and the abdomen during whole-body vibration
1989
Vibration strain may be defined as the sum of all reactions of the human being to vibration exposure. This also includes the biomechanical behavior of particular parts of the body. Knowledge about these reactions is necessary in the field of occupational health and ergonomics. Biomechanical models, experimental methods, and results are presented. It can be shown that under vibration exposure with different conditions (body posture, vibration direction), the body parts are in resonance at varying frequencies, mainly in a low frequency range.
The Northern Bolivian Altiplano: a region highly endemic for human fascioliasis.
1999
The worldwide importance of human infection by Fasciola hepatica has been recognized in recent years. The endemic region between Lake Titicaca and the valley of La Paz, Bolivia, at 3800-4100 m altitude, presents the highest prevalences and intensities recorded. Large geographical studies involving Lymnaea truncatula snails (malacological, physico-chemical, and botanic studies of 59, 28 and 30 water bodies, respectively, inhabited by lymnaeids; environmental mean temperature studies covering a 40-year period), livestock (5491 cattle) and human coprological surveys (2723 subjects, 2521 of whom were school children) were conducted during 1991-97 to establish the boundaries and distributional c…
An ab initio study of the tautomeric equilibria of the N-oxides of hydroxypyridines in the vapour phase
1993
Abstract An ab initio self-consistent field molecular orbital study of the N-oxides of hydroxypyridines has been carried out. The optimized structures have been obtained at the 6-31G ∗ level, and the energy values have been computed at the 6-31G ∗ and MP2-6-31G ∗ //6-31G ∗ levels. The tautomerization energies for the three couples of systems in the vapour phase have been evaluated.
Continuum Monte Carlo simulation of phase transitions in rod-like molecules at surfaces
1994
Stiff rod-like chain molecules with harmonic bond length potentials and trigonometric bond angle potentials are used to model Langmuir monolayers at high densities. One end of the rod-like molecules is strongly bound to a flat two-dimensional substrate which represents the air-water interface. A ground-state analysis is performed which suggests phase transitions between phases with and without collective uniform tilt. Large-scale off-lattice Monte Carlo simulations over a wide temperature range show in addition to the tilting transition the presence of a strongly constrained melting transition at high temperatures. The latter transition appears to be related to two-dimensional melting of th…
A theoretical determination of the dissociation energy of the nitric oxide dimer
1994
Multi-reference CI methods have been applied to determine the dissociation energy and structure of thecis-N2O2 molecule. The convergence of the theoretical result has been checked with respect to a systematic expansion of the one-electron basis set and the multi-reference CI wave function. The best calculated value, 13.8 kJ/mol, is in agreement with the experimental value, 12.2 kJ/mol. It has been obtained with an extended ANO-type basis set [6s5p3d2f], including the effect of the basis set superposition error (BSSE) in the geometry optimization, and additional effects, such as the electron correlation of core electrons and relativistic corrections, using the average coupled pair functional…
Influence of metal ions on the structures of Keggin polyoxometalate-based solids: Hydrothermal syntheses, crystal structures and magnetic properties
2006
Abstract Three new Keggin polyoxometalate (POM)-based compounds linked to 3d metal complexes have been synthesized under hydrothermal conditions: [Cu(phen)2]2{[Cu(phen)]2 [SiMo12O40(VO)2]} (1), {[Zn(phen)2]2[GeMo12O40(VO)2]}{[Zn(phen)2(H2O)]2 [GeMo12O40(VO)2]}·3H2O (2) and {[Co(phen)2]2[PMo12O40(VO)2]}{[Co(phen)2(OH)]2 [PMo12O40(VO)2]}·2.5H2O (3) (phen=1,10-phenanthroline). These three compounds present, as building blocks, the bicapped Keggin anions [XMo12O40(VO)2] (X=Si, Ge and P). Compound 1 consists of a bicapped Keggin anion [SiMo12O40(VO)2]2− linked to two [Cu(phen)]+ complexes with two [Cu(phen)2]+ countercations. Compound 2 contains two bicapped Keggin anions [GeMo12O40(VO)2]4−, one…
Multidomain BEM for crack analysis in stiffened anisotropic plates.
2014
The present paper is concerned with the application of a boundary element model for the analysis of cracks in stiffened composite panels. The panel stiffeners are reduced to equivalent strips and the multidomain technique is used to model panel zones presenting different properties (skin and stiffeners equivalent strip). Also the crack is modeled exploiting the multidomain formulation. Evaluation of stress intensity factors is performed for representative problems.
Position-sensitive neutron detector
2002
Abstract A position-sensitive neutron detector has been developed for use in nuclear physics research. The detector consists of a ∅5.5 cm×100 cm long quartz tube filled with liquid scintillator viewed from both ends by photomultipliers and enclosed in a light-tight titanium container. The properties of the detector were determined both experimentally and by Monte Carlo simulations (EFEN code). A time resolution of 0.4 ns was reached resulting in the position resolution of less than 4 cm. The neutron registration efficiency varies from 36% to 20% within neutron energy range 1–10 MeV and is practically independent of the position along the detector length. Good n–γ separation is achieved for …
Evaluation of Record Linkage Methods for Iterative Insertions
2009
Summary Objectives: There have been many developments and applications of mathematical methods in the context of record linkage as one area of interdisciplinary research efforts. However, comparative evaluations of record linkage methods are still underrepresented. In this paper improvements of the Fellegi-Sunter model are compared with other elaborated classification methods in order to direct further research endeavors to the most promising methodologies. Methods: The task of linking records can be viewed as a special form of object identification. We consider several non-stochastic methods and procedures for the record linkage task in addition to the Fellegi-Sunter model and perform an e…
Bagging and Boosting with Dynamic Integration of Classifiers
2000
One approach in classification tasks is to use machine learning techniques to derive classifiers using learning instances. The co-operation of several base classifiers as a decision committee has succeeded to reduce classification error. The main current decision committee learning approaches boosting and bagging use resampling with the training set and they can be used with different machine learning techniques which derive base classifiers. Boosting uses a kind of weighted voting and bagging uses equal weight voting as a combining method. Both do not take into account the local aspects that the base classifiers may have inside the problem space. We have proposed a dynamic integration tech…