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Search Results: 1 - 10 of 284376 matches for " T. G.;Buezas "
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Proper orthogonal decomposition for model reduction of a vibroimpact system
Ritto, T. G.;Buezas, F. S.;Sampaio, Rubens;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2012, DOI: 10.1590/S1678-58782012000300013
Abstract: the application that inspires this work is the percussion drilling. this problem has impacts and presents uncertainties. in this first analysis the focus is on the construction of an efficient reduced-order model to deal with the nonlinear dynamics due to the impacts. it is important to have an efficient reduced-order model to perform the stochastic analysis. the simplified full model is constructed using the finite element method, and three different bases are used to construct the reduced-order models: lin-basis (composed by the normal modes of the associated linear problems), poddir-basis (obtained through proper orthogonal decomposition -direct method) and podsnap-basis (obtained through proper orthogonal decomposition -snapshot method). the shapes of the elements of lin-basis, poddir-basis, and podsnap-basis are compared. one important conclusion is that the information necessary to represent the details of a vibroimpact dynamics, measured by the proper orthogonal values, is more than the usual 99% recommended.
Varones al son de la migración. Migración internacional y masculinidades de Veracruz a Chicago. Carolina Rosas
Tomás Calvo Buezas
Política y Sociedad , 2011, DOI: -
Abstract: Sin resumen
Some nonlinear mechanical problems solved with analytical solutions
Filipich,C. P.; Rosales,M. B.; Buezas,F.;
Latin American applied research , 2004,
Abstract: in this paper the analytical solution of nonlinear ordinary differential systems is addressed. some of the problems are classical in the related literature and exhibit chaotic behavior in certain ranges of the involved parameters despite being simple-looking deterministic systems. the solutions are approached by means of the old technique of power series to solve ordinary differential equations. the independent variable is time in all the illustrations and elementary recurrence algorithms are obtained. this is an alternative to the standard numerical techniques and ensures the theoretical exactness of the response. several examples are included and trajectories diagrams, phase plots, etc. are shown. the desired numerical precision is attained using time steps several times larger than the usual ones. the availability of an analytical solution may be an additional tool within a standard qualitative analysis. the solution of higher order problems and governed by partial differential equations is under study.
Some nonlinear mechanical problems solved with analytical solutions
C. P. Filipich,M. B. Rosales,F. Buezas
Latin American applied research , 2004,
Abstract: In this paper the analytical solution of nonlinear ordinary differential systems is addressed. Some of the problems are classical in the related literature and exhibit chaotic behavior in certain ranges of the involved parameters despite being simple-looking deterministic systems. The solutions are approached by means of the old technique of power series to solve ordinary differential equations. The independent variable is time in all the illustrations and elementary recurrence algorithms are obtained. This is an alternative to the standard numerical techniques and ensures the theoretical exactness of the response. Several examples are included and trajectories diagrams, phase plots, etc. are shown. The desired numerical precision is attained using time steps several times larger than the usual ones. The availability of an analytical solution may be an additional tool within a standard qualitative analysis. The solution of higher order problems and governed by partial differential equations is under study.
Influence of VAM Fungi, Azotobacter sp. and PSB on Soil Phosphatase Activity and Nutrients (N, P, K, Cu, Zn, Fe and Mn) Status in the Rhizosphere of Stevia rebaudiana (Bert.) Plants  [PDF]
G. Ramakrishnaiah, T. Vijaya
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.47176
Abstract:

The pot culture experiment was carried out to evaluate the influence of different combinations of microbial inoculants (VAM + AZO + PSB) on soil phosphatase activity andnutrients (N, P, K, Cu, Zn, Fe, Cu & Mn) of Steviarebaudia plant rhizosphere on 20th, 40th and 60th day. The study revealed that the combined application of microbial inoculants onsoil Alkaline and Acid phosphatase activity has been found maximum at 60th day in triple inoculated plants than dual inoculated and control. The results also showed that the soil macronutrients (N, P & K) and micronutrients (Zn, Fe, Cu & Mn) have been found to be maximum at 40th day and 60th day respectively in triple inoculated plants than dual inoculated and control.

Hematocrit and Slip Velocity Influence on Third Grade Blood Flow and Heat Transfer through a Stenosed Artery  [PDF]
A. Jimoh, G. T. Okedayo, T. Aboiyar
Journal of Applied Mathematics and Physics (JAMP) , 2019, DOI: 10.4236/jamp.2019.73046
Abstract: A theoretical investigation concerning hematocrit and slip velocity influence on the flow of blood and heat transfer by taking into account the externally applied magnetic field has been carried out. The mathematical models considered in this work treated blood as a non-Newtonian fluid obeying the third grade fluid model. A suitable geometry of the stenosis is taken into account. Galerkin weighted residual and Newton Raphson methods are used to solve the equations that govern the flow of blood and heat transfer. Analytical expression for the velocity profile, temperature profile, volume flow rate, wall shear stress and resistance to flow were obtained. Graphical representation of results shows that the flow velocity, volumetric flow rate and shear stress increase while resistance to flow and heat transfer rate decrease when the slip velocity increases. Also, flow velocity and volume flow rate decrease while shear stress, heat transfer rate, and resistance to flow increase when the hematocrit parameter increases. Finally, increases in magnetic field parameter lead to decrease in flow velocity, flow rate and shear stress but increase the flow resistance.
Imaging characteristics of metallic interbody spacers: in vitro score evaluation of susceptibility artifacts considering different MRI sequences  [PDF]
T. Ernstberger, G. Heidrich, G. Buchhorn
Journal of Biomedical Science and Engineering (JBiSE) , 2010, DOI: 10.4236/jbise.2010.32023
Abstract: Aim: Intervertebral spacers for anterior spine fusion are made of different materials, such as titanium, carbon or cobalt-chrome, which can affect the post- fusion MRI scans. Implant-related susceptibility artifacts can decrease the quality of MRI scans, thwar- ting proper evaluation. This cadaver study aimed to demonstrate the extent that implant-related MRI artifacting affects the post-fusion evaluation of intervertebral spacers. Methods: In a cadaveric porcine spine, we evaluated the post-implantation MRI scans of 2 metallic intervertebral spacers (TiAL6V4, CoCrMo) that differed in shape, material, surface qualities and implantation technique. A spacer made of human cortical bone was used as a control. The median sagittal MRI slice was divided into 12 regions of interest (ROI). Results: No significant differences were found on 15 different MRI sequences read independently by an interobserver-validated team of specialists (P>0.05). Artifact-affected image quality was rated on a score of 0-1-2. A maximum score of 24 points (100%) was possible. Turbo spin echo sequences produced the best scores for all spacers and the control. Only the control achieved a score of 100%. The titanium and cobalt-chrome spacers scored 62.5% and 50%, respectively. Conclusions: Our scoring system allowed us to create an implant-related rank- ing of MRI scan quality in reference to the control that was independent of artifact dimensions. Even with turbo spin echo sequences, the susceptibility artifacts produced by the metallic spacers showed a high degree of variability. Despite optimum sequen- cing, implant design and material are relevant factors in MRI artifacting.
Bounds for Domination Parameters in Cayley Graphs on Dihedral Group  [PDF]
T. Tamizh Chelvam, G. Kalaimurugan
Open Journal of Discrete Mathematics (OJDM) , 2012, DOI: 10.4236/ojdm.2012.21002
Abstract: In this paper, sharp upper bounds for the domination number, total domination number and connected domination number for the Cayley graph G = Cay(D2n, Ω) constructed on the finite dihedral group D2n, and a specified generating set Ω of D2n. Further efficient dominating sets in G = Cay(D2n, Ω) are also obtained. More specifically, it is proved that some of the proper subgroups of D2n are efficient domination sets. Using this, an E-chain of Cayley graphs on the dihedral group is also constructed.
Asymptotic Comparison of Method of Moments Estimators and Maximum Likelihood Estimators of Parameters in Zero-Inflated Poisson Model  [PDF]
G. Nanjundan, T. Raveendra Naika
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.36095
Abstract: This paper discusses the estimation of parameters in the zero-inflated Poisson (ZIP) model by the method of moments. The method of moments estimators (MMEs) are analytically compared with the maximum likelihood estimators (MLEs). The results of a modest simulation study are presented.
On the Thermodynamics of a Two-Dimensional Electron Gas with Non-Parabolic Dispersion  [PDF]
G. Gulyamov, B. T. Abdulazizov
World Journal of Condensed Matter Physics (WJCMP) , 2016, DOI: 10.4236/wjcmp.2016.64028
Abstract: A thermodynamic density of states, electron density in the subband and the entropy of the gas as function of the temperature and the total two-dimensional electron density are studied. Semiconductor conduction band dispersion is described by the simplified Kane model. Numerical simulation shows that with an increase in the total electron concentration, thermodynamic density of states at low temperatures changes abruptly and smoothes jumps at high temperatures. This change manifests itself in the peculiar thermodynamic characteristics. The results are used to interpret existing experimental data.
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