Now showing items 51-60 of 76
The influence of magnetic field on nanoparticle transport in a micro channel
The present study focuses on a new solver considering the effect of magnetic field on nanoparticles concentration in a micro size channel. To describe the multi component behavior of blood, the Euler‐Euler method is used. Particles are modeled by a concentration equation considering a magnetic drift. The influence of a realistic magnetic field on nanoparticles is investigated. A result for a test case is presented. It shows that the magnetic body force resulting from nanoparticles also influence the hematocrit ...
Actuation of an elastic membrane by the use of an electrorheological valve
The dynamic response of a fluidic actuator is investigated on the basis of numerical simulations. With this actuator a membrane is excited to oscillate by means of an electrorheological valve. For this purpose the solid and fluid domains are coupled. Furthermore, the constitutive equation of the fluid is coupled to the electric field. The dynamic response is discussed on the example of a variable stiffness of the membrane. Actuators of this type offer the potential to delay the transition of a boundary layer.
Simultaneous determination of Bingham material parameters using a ball probe concrete rheometer
A new evaluation method allowing direct determination of the Bingham parameters from ball probe rheometers. A non‐linear relationship between the direct measured variables and the material parameters is revealed through numerical parameter studies. The method was validated on two devices of the ball probe type with different dimensions. Comparison with other methods showed good agreement. It is pointed out how the evaluation method can be transferred to devices having other dimensions by performing a limited number ...
Experimental investigations of viscoelastic and ferroelectric heating in PZT–5H
This contribution focuses on the separation of two effects causing a temperature change in experiments with electrically loaded ferroelectrics. These materials are often subjected to cyclic loading, where viscoelasticity prevails at lower electric fields, whereas dissipative heating by domain switching governs the heating above the coercive field. Different frequencies and load amplitudes are investigated experimentally.
Measuring the Time Discretization Error in Linear Elasticity
The present paper considers the spread of longitudinal waves in an elastic rod. On the one hand an analytical solution is presented, on the other hand a spatially and temporally discretized continuum formulation of this problem is treated. With these approaches at hand the appearing time discretization error is analyzed using various quantities.
Efficient Solution of Distributed MIP in Control of Networked Systems
Certain classes of optimization‐based control problems stated for networked systems involving hybrid dynamics and logical constraints can be cast into Mixed‐Integer Programming (MIP) problems. Since these belong to the complexity class NP‐hard, the motivation arises to find approximations of the optimal solution by distributed solution efficiently. For the cases that the cost functional is linear or quadratic and the constraints are linear, this paper proposes an alternative to the standard centralized schemes, by ...
Assessing spatial variability of barley whole crop biomass yield and leaf area index in silvoarable agroforestry systems using UAV-borne remote sensing
Agroforestry systems (AFS) can provide positive ecosystem services while at the same time stabilizing yields under increasingly common drought conditions. The effect of distance to trees in alley cropping AFS on yield-related crop parameters has predominantly been studied using point data from transects. Unmanned aerial vehicles (UAVs) offer a novel possibility to map plant traits with high spatial resolution and coverage. In the present study, UAV-borne red, green, blue (RGB) and multispectral imagery was utilized ...
Mitigating pro-poor housing failures: Access theory and the politics of urban governance
Looking at evolving urban governance and planning practices in the city of Lahore, Pakistan, the article aims to understand—from an Evolutionary Governance Theory perspective—to what extent these practices steer paths and modes of service provision and housing for low-income residents. With a focus on the endurance and transformations of urban governance practices and institutions, we first explore the influence of the changing development discourse and the impact it has had on the (re)configuration of urban governance ...
An Overview of the Use of Genotyping Techniques for Assessing Genetic Diversity in Local Farm Animal Breeds
The number of local farm animal breeds is declining worldwide. However, these breeds have different degrees of genetic diversity. Measuring genetic diversity is important for the development of conservation strategies and, therefore, various genomic analysis techniques are available. The aim of the present work was to shed light on the use of these techniques in diversity studies of local breeds. In summary, a total of 133 worldwide studies that examined genetic diversity in local cattle, sheep, goat, chicken and pig ...
Net Energy Balance and Fuel Quality of an Alley Cropping System Combining Grassland and Willow: Results of the 2nd Rotation
With the central aim to reduce greenhouse gas emissions, agroforestry systems have become popular because they can provide biomass for bioenergy conversion and thus help replace fossil energy. This article compares the net energy balances of three biomass conversion techniques for an agroforestry system consisting of willows and two types of grassland biomass as well as separate stands of grassland and willow. The period of investigation was the second willow rotation (4–6 years after establishment). The biomass ...