Evaluación de cinco productos botánicos para el manejo del ácaro blanco (Polyphagotarsonemus latus, Banks.)en chiltoma (Capsicum annuum L.), en Tisma Masaya

Con el objetivo de evaluar cinco productos botánicos para el manejo del ácaro blanco de la chiltoma, se realizó un estudio en el Municipio de Tisma, Masaya en el período comprendido de Septiembre a Noviembre del año 2014. Las alternativas evaluadas fueron: Eucalipto, Neem, Crisantemo, Madero Negro y Chile+Ajo+Jabón en comparación con el testigo que fue solamente aplicación de agua. Las variables evaluadas fueron: Número de ácaro blanco por planta, porcentaje de severidad del daño de ácaro blanco por planta, número de mosca blanca, Halticus, Diabrótica y Minador por planta, y numero de hormigas y arañas por planta, además de algunas variables económicas como el rendimiento en kg/ha por tratamiento evaluado, análisis de presupuesto parcial, análisis de dominancia y tasa de retorno marginal mediante la metodología CIMMYT. Los resultados obtenidos en el estudio determinan que los tratamientos Madero Negro y Chile+Ajo+Jabón fueron los que presentaron el mejor efecto de control del ácaro blanco, el tratamiento madero negro presentó el mejor control de Mosca Blanca, Halticus, Minador de la hoja y Diabrótica, los tratamientos que tuvieron el menor efecto sobre los organismos benéficos fueron Neem, Eucalipto y Chile+Ajo+Jabón , los mejores rendimientos comerciales lo obtuvieron los tratamientos madero negro y Chile+Ajo+Jabón, las mejores tasas de retorno marginal fueron obtenidas en los tratamientos madero negro seguido del Chile+Ajo+Jabón.

Ocurrencia poblacional del ácaro blanco (Polyphagotarsonemus latus, Banks) (Acarina: Tarsonemidae) y otros artrópodos plagas y benéficos en chiltoma (Capsicum annuum L.) en policultivo y monocultivo en Tisma, Masaya, Septiembre - Noiembre, 2014

El estudio se realizó en el municipio Tisma, Masaya en la finca “El Cha güit e” en los meses de Septiembre a Noviembre del 2014 , con el objetivo de estudiar el efecto de dos sistemas de siembra , monocultivo y policultivo, sobre la o currencia poblacional de artrópodos plagas y benéficos y severidad del ataque de l á caro blanco en el cultivo de c hiltoma . Para el desarrollo de la investigación se estableciero n cuatro parcelas, una con el arreglo en poli cultivos de chiltoma, maíz, tomate , y uca y quequisque; y los restantes se establecieron con monocultivo de chiltom a, maíz y tomate . Las variab les evaluadas semanalmente fuero n la o currencia poblacional de artrópodos plagas y benéficos , o currencia y se veridad del ácaro blanco y el rendimiento obteni do en los cultivos de chiltoma, maíz y tomate para el análisis del uso equivalente de la tierra ( LER ) . Los datos obtenidos se analizaro n a través de medias, error estándar de la media, análisis de varianza y separación de medias por Tukey a un nivel de con fianza del 95%, utilizando el programa InfoStat versión 2015 . El sistema de siembra policultivo presentó menor o currencia de plagas (0.95 individuos por planta) , menor densi d ad poblacional de ácaro blanco (1.77 individuos por planta) , menor severi dad en el ataque de ácaro blanco (74.33%) , mayor densidad poblacional de artrópodos benéfico s (0.06 individuos por planta) y un mejor aprovechamient o de la tierra por unidad de área

Rigorous finite-time guarantees for optimization on continuous domains by simulated annealing

Simulated annealing is a popular method for approaching the solution of a global optimization problem. Existing results on its performance apply to discrete combinatorial optimization where the optimization variables can assume only a finite set of possible values. We introduce a new general formulation of simulated annealing which allows one to guarantee finite-time performance in the optimization of functions of continuous variables. The results hold universally for any optimization problem on a bounded domain and establish a connection between simulated annealing and up-to-date theory of convergence of Markov chain Monte Carlo methods on continuous domains. This work is inspired by the concept of finite-time learning with known accuracy and confidence developed in statistical learning theory.

Three-dimensional crack problem analysis using boundary element method with finite-part integrals

A set of hypersingular integral equations of a three-dimensional finite elastic solid with an embedded planar crack subjected to arbitrary loads is derived. Then a new numerical method for these equations is proposed by using the boundary element method combined with the finite-part integral method. According to the analytical theory of the hypersingular integral equations of planar crack problems, the square root models of the displacement discontinuities in elements near the crack front are applied, and thus the stress intensity factors can be directly calculated from these. Finally, the stress intensity factor solutions to several typical planar crack problems in a finite body are evaluated.

Chaos of liquid surface waves in a vessel under vertical excitation with slowly modulated amplitude

Free surface waves in a cylinder of liquid under vertical excitation with slowly modulated amplitude are investigated in the current paper. It is shown by both theoretical analysis and numerical simulation that chaos may occur even for a single mode with modulation which can be used to explain Gollub and Meyer's experiment. The implied resonant mechanism accounting for this phenomenon is further elucidated.

Compact finite difference - Fourier spectral method for three-dimensional incompressible Navier-Stokes equations

A new compact finite difference-Fourier spectral hybrid method for solving the three dimensional incompressible Navier-Stokes equations is developed in the present paper. The fifth-order upwind compact finite difference schemes for the nonlinear convection terms in the physical space, and the sixth-order center compact schemes for the derivatives in spectral space are described, respectively. The fourth-order compact schemes in a single nine-point cell for solving the Helmholtz equations satisfied by the velocities and pressure in spectral space is derived and its preconditioned conjugate gradient iteration method is studied. The treatment of pressure boundary conditions and the three dimensional non-reflecting outflow boundary conditions are presented. Application to the vortex dislocation evolution in a three dimensional wake is also reported.

Study of three elastic-plastic constitutive models by non-proportional finite deformations of OFHC copper

Experimental stress-strain data of OFHC copper first under torsion to 13% and then under torsion-tension to about 10% are used to study the characteristics of three elastic-plastic constitutive models: Chaboche's super-positional nonlinear model, Dafalias and Popov's two surface model and Watanabe and Atluri's version of the endochronic model. The three models, originally oriented for infinitesimal deformation, have been extended for finite deformation. The results show (a) the Mises-type yield surface used in the three models brings about significant departure of the predictions from the experimental data; (b) Chaboche's and Dafalias' models are easier than Watanabe and Atluri's model in determining the material parameters in them, and (c) Chaboche's and Watanabe & Atluri's models produce almost the same prediction to the data, while Dafalias' model cannot accurately predict the plastic deformations when a loading path changes in its direction. Copyright (C) 1996 Elsevier Science Ltd

A finite deformation analysis of polycrystal by considering the influence of grain boundary

By combining grain boundary (GB) and its influence zone, a micromechanic model for polycrystal is established for considering the influence of GB. By using the crystal plasticity theory and the finite element method for finite deformation, numerical simulation is carried out by the model. Calculated results display the microscopic characteristic of deformation fields of grains and are in qualitative agreement with experimental results.

Saturation impulses for dynamically loaded structures with finite-deflections

The concept of ''Saturation Impulse'' for rigid, perfectly plastic structures with finite-deflections subjected to dynamic loading was put forward by Zhao, Yu and Fang (1994a). This paper extends the concept of Saturation Impulse to the analysis of structures such as simply supported circular plates, simply supported and fully clamped square plates, and cylindrical shells subjected to rectangular pressure pulses in the medium load range. Both upper and lower bounds of nondimensional saturation impulses are presented.