Model Integration and Coupling in A Hydroinformatics System

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

How fast the Laplace equation was solved in 1995

On the occasion of the third centenary of the appointment of Johann Bernoulli at the University of Groningen, a number of linear systems solvers for some Laplace-like equations have been compared during a one-day workshop. CPU times of several advanced solvers measured on the same computer (an HP-755 workstation) are presented, which makes it possible to draw clear conclusions about the performance of these solvers

The use of topical Nitrosomonas eutropha for cosmetic improvement of facial wrinkles

BackgroundBoth topical and oral probiotics are becoming widely used. There is increasing interest in the cosmetic potential in topical probiotics. Nitrosomonas eutropha is an ammoniaâ oxidizing bacteria.AimThe purpose of this study was to assess whether there is any improvement in facial wrinkles with the use of Nitrosomonas eutropha, a topical probiotic.MethodsIn this prospective study, highâ resolution photographs were obtained in twentyâ nine participants at baseline and after using topical Nitrosomonas eutropha for seven days.ResultsThere was a significant difference in wrinkle depth and severity in the high concentration probiotic group. There was also a statistically significant improvement in pigmentation of the forehead and glabella in the higher concentration group.ConclusionsNitrosomonas eutropha may have aesthetic benefits in terms of reducing the appearance of wrinkles. Larger studies with longer treatment and followâ up periods are required.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154401/1/jocd13060_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154401/2/jocd13060.pd

Dynamics of the speed changes control device with differential gear and closed-loop hydraulic system through the sun gear

Розглянуті та досліджені динамічні процеси у пристрої для керування змінамишвидкості з зубчастою диференціальноюпередачеюі замкнутою гідросистемою через сонячне зубчасте колесо, коли ведучою ланкою є водило, а веденою – епіцикл. Розроблена математична модель та розв’язані рівняння динаміки таких пристроїв залежно від умов їх роботи. Отримані результати є підґрунтям для подальшого комп’ютерного моделювання та проведення кількісного аналізу з метоюоцінки роботи гідромеханічного приводу та вибору необхідної замкнутої гідросистеми для керування змінамишвидкості.Dynamic processes in speed changes control device with differential gear transmission and closed loop hydraulic system have been considered and investigated for the case when the sun gear is a control link, carrier is a driving link and the ring gear is driven. The motion of the system has been modeled in a formalized form using the Lagrange’s equation of the second kind. For this purpose, the expression for the energy of such speed changes control device has been derived. Then, based on the Lagrange’s equation of second kind, a system of differential equations for the motion of the links has been obtained and solved. The solution of the system of equations of dynamics of such devices is the basis for further computer simulation and quantitative analysis in order to evaluate the operation of such devices and to select the necessary closed loop hydraulic system to control changes in speed, when the load changes periodically over a long time; or when the magnitude of the shock load after a sharp increase remains unchanged for either a long time or a small time; or the actuator stops immediately because of a significant overload

Algebraic multigrid for moderate order finite elements

We investigate the use of algebraic multigrid (AMG) methods for the solution of large sparse linear systems arising from the discretization of scalar elliptic partial differential equations with Lagrangian finite elements of order at most 4. The resulting system matrices do not have the M-matrix property that is required by standard analyses of classical AMG and aggregation-based AMG methods. A unified approach is presented that allows us to extend these analyses. It uses an intermediate M-matrix and highlights the role of the spectral equivalence constant that relates this matrix to the original system matrix. This constant is shown to be bounded independently of the problem size and jumps in the coefficients of the partial differential equations, provided that jumps are located at elements' boundaries. For two-dimensional problems, it is further shown to be uniformly bounded if the angles in the triangulation also satisfy a uniform bound. This analysis validates the application of the AMG methods to the considered problems. On the other hand, because the intermediate M-matrix can be computed automatically, an alternative strategy is to define the AMG preconditioners from this matrix, instead of defining them from the original matrix. Numerical experiments are presented that assess both strategies using publicly available state-of-theart implementations of classical AMG and aggregation-based AMG methods.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Parameter free algebraic multilevel preconditioning

info:eu-repo/semantics/nonPublishe