Stability of Liquid Bridges between Unequal Disks under Zero-Gravity Conditions

The stability, of axisymmetric equilibrium shapes of a liquid bridge between two coaxial disks of different radii under zero-gravity conditions is investigated. The stability regions have been evaluated for different values of the ratio of the disk radii in terms of the dimensionless parameters which characterize the length and the volume of the bridge. It has been found that disk radii unequality radically changes the upper boundary of the stability region. The analysis of the shape of marginally stable equilibrium surfaces has been carried out. Relationships between the critical values of the parameters have been deduced for some particular cases, which are of special interest for the materials purification processes and growing of single crystals by the floating zone method: for typical values of the growing angle for semiconductor materials and for liquid volumes close to that of the cylinder having a radius equal to the mean radius of the disk

Mechanical Imperfections Effect on the Minimum Stability Limit of Liquid Bridges

The bifurcation to unstable equilibrium shapes in the neighborhood of the minimum volume stability limit of liquid bridges has been described by using the Lyapunov–Schmidt technique. Prior to the bifurcation analysis, the stability limits of axisymmetric liquid bridges (both that of maximum and that of minimum volume) have been analytically calculated when the liquid bridge supports are two circular, coaxial disks. The interface shapes have been parametrically described and the parameters corresponding to the marginally stable shapes have been determined in terms of elliptic variables. Bifurcation equations have been obtained analytically describing the behavior near the critical points previously calculated and the effect of small axisymmetric imperfections has been considered. The considered imperfections are inequality in the diameter of the supporting disks, small body forces due to an axial gravity, and liquid bridge rotation as a solid bod

On the Stability Limit Change due to Imperfections

The minimum volume stability limit of axisymmetric liquid bridges has been obtained in the past for zero Bond number, no solid body rotation and equal disks. When gravity, rotation or different disk diameters are considered, only a few numerical results are available and the singular case of small values of these parameters have been only partly considered. An analytical study using the Lyapunov-Schmidt method considering small values of gravity, disk diameter ratio and rotation rate is presented and the variation of the stability limit determined

Effects of Axial and Centrifugal Forces on the Stability of Liquid Bridges

The equilibrium and stability equations for liquid bridges are well known, but they are nonlinear and it is difficult to guess real behavior, such as the sensitivity of the shape to axial and rotational forces (measured by Bond and Weber numbers, respectively) or to the geometry of the solid supports that support the bridge. A parametric study by numerical methods of the different effects and the analytical solutions at the bifurcation points in the stability diagrams is presented. The well known shooting method to numerically compute equilibrium shapes of liquid bridges, and their stability limits, is applied to a five parameter case, when different disc sizes (measured by H), bridge lengths (Lr), liquid volumes (Vr), residual axial acceleration (Bo), and solid body centrifugation (We) are contemplated. The bundle of diagrams presented give an idea of the complexities of such a multiparametric analysis and may help in further research to delimitate other forms of instability. The numerical results were used to check the validity of several analytical asymptotic expressions, with perfect agreement over the range of interest (long liquid bridges), but these models only take into consideration the subset (Lr, Vr = 1, H = 0, Bo, We) of the five parameter family. These results will be of great help to plan future space experiments on liquid columns and floating zones in space and in particular will show a method to easily measure very weak residual forces in microgravity platforms

Implementación de un sistema ERP para mejorar el control de inventario de la Librería Bazar “Diamante Azul” en el distrito de El Tambo en el año 2020

El presente trabajo de investigación se ha realizado en la Librería Bazar “Diamante Azul” en el distrito de El Tambo en el año 2020 la cual presenta una serie de deficiencias en el manejo de sus inventarios. Este trabajo consiste en demostrar que la implementación de un sistema ERP mejorará el control del inventario en la empresa antes mencionada. La metodología que se utilizó en la investigación es ASAP que consiste en el desarrollo de entregables por etapas que racionaliza los proyectos de implementación, minimizando los riesgos y reduciendo los costos. Asimismo se tiene un enfoque cuantitativo ya que mide las dimensiones definidas en el trabajo de investigación las cuales son: duración de productos, rotación de productos y exactitud en inventarios. Como resultado se ha podido evidenciar un ligero aumento en el promedio en la duración de los productos de 13.81 a 14.32 días, por otro lado se evidenciado una disminución del máximo de días de un producto en almacén que se redujo de 136 a 53 días. En cuanto a rotación de ha incrementado de 2.65 a 3.15 el promedio de rotación de productos al mes, evidenciándose un incremento significativo del movimiento de productos que tiene el negocio. También se ha notado un incremento en cuanto a la exactitud del inventario acercándose a valores cercanos al 100% indicándonos así, un fuerte incremento en la exactitud del inventario

Bayesian Multivariate Spatial Models for Lattice Data with INLA

The INLAMSM package for the R programming language provides a collection of multivariate spatial models for lattice data that can be used with package INLA for Bayesian inference. The multivariate spatial models include different structures to model the spatial variation of the variables and the between-variables variability. In this way, fitting multivariate spatial models becomes faster and easier. The use of the different models included in the package is illustrated using two different datasets: the well-known North Carolina SIDS data and mortality by three causes of death in Comunidad Valenciana (Spain)

Análisis del sistema de detracciones, en una empresa de servicios, periodos: 2022-2023

El presente estudio, analizó las detracciones en una empresa de servicios por los periodos 2022 y 2023. La metodología utilizada fue de enfoque cuantitativo, de tipo descriptivo y diseño no experimental, con aplicación del análisis documental como técnica de recolección y la ficha de análisis como instrumento. Los resultados demuestran que el promedio de detracciones anual del periodo asciende a S/ 1 792,49; siendo el año 2022 en el que se obtuvo el mayor promedio de detracciones con un total de S/ 1 841,42, encontrándose errores en las constancias de depósitos dentro del código de servicio brindado, además de detracciones no depositadas por los servicios de impresión e instalación, debido a la falta de aplicación de auto detracciones, que de no ser subsanados resultaría en un futuro perjudicial para la empresa por las sanciones del sistema. Se concluye que, los importes detraídos durante los meses del periodo estudiado permitieron cubrir los impuestos de IGV – Renta mensuales en un 67% para el año 2022 y en un 56%, considerando los meses enero a setiembre para el 2023, además se enfatiza que el porcentaje restante no pudo ser cubierto a consecuencia de un aumento en las ventas no sujetas al sistema

Pru p 3 mutants exhibit low IgE-binding capacity: a good strategy for specific peach immunotherapy.

Treatment of food allergy consists of the avoidance of the specific allergenic food. However, the possibility of cross-reactivity with other food sources makes this practice sometimes ineffective. The use of hypoallergenic molecules with the ability to stimulate T cells may be a promising tool for specific immunotherapy

Component-resolved diagnosis of wheat flour allergy in baker's asthma.

Baker's asthma is one of the most common types of occupational asthma and its prevalence is increasing in the last years. Diagnosis of occupational asthma is complex. The poor specificity of current diagnostic approaches may be associated with insufficient purity of wheat extracts or lack of inclusion of major allergens in them. In this work, we use microarray technology to characterize the allergenic profiles of baker's asthma patients from three regions in Spain and to analyze the influence of other environmental allergens on the sensitization pattern