422 research outputs found
Sol-Gel Prepared Nanoscopic Metal Fluorides - a New Class of Tunable Acid-Base Catalysts
In this article, the high potential of the fluorolytic sol-gel process to synthesise nanoscopic metal fluorides with different acid-base properties is shown. These nanoscopic materials exhibit high potential to be used as heterogeneous catalysts due to their high surface areas and their tunable surface properties. Thus, for each specific reaction the required surface properties of the catalysts can be ”adjusted” to achieve a high yield and selectivity of the desired product. As a consequence, a greener method of chemical production can be accomplished. Moreover the cheap and easy synthesis of the catalysts using basic chemicals makes them not only interesting for fundamental research but provides an easy transformation to industrial applications
Computational Based Investigation of Lattice Cell Optimization under Uniaxial Compression Load
Structural optimization is a methodology used to generate novel structures within a design space by finding a maximum or minimum point within a set of constraints. Topology optimization, as a subset of structural optimization, is often used as a means for light-weighting a structure while maintaining mechanical performance. This article presents the mathematical basis for topology optimization, focused primarily on the Bi-directional Evolutionary Structural Optimization (BESO) and Solid Isotropic Material with Penalization (SIMP) methodologies, then applying the SIMP methodology to a case study of additively manufactured lattice cells. Three lattice designs were used: the Diamond, I-WP, and Primitive cells. These designs are all based on Triply Periodic Minimal Surfaces (TPMS). Individual lattice cells were subjected to a uniaxial compression load, then optimized for these load conditions. The optimized cells were then compared to the base cell designs, noting changes in the stress field response, and the maximum and minimum stress values. Overall, topology optimization proved its utility under this loading condition, with each cell seeing a net gain in performance when considering the volume reduction. The I-WP lattice saw a significant stress reduction in conjunction with the mass and volume reduction, marking a notable increase in cell performance
Particle-in-cell Simulation Concerning Heat-flux Mitigation Using Electromagnetic Fields
The Particle-in-Cell (PIC) method was used to study heat flux mitigation experiments with argon. In the experiment it was shown that a magnetic field allows to reduce the heat flux towards a target. PIC is well-suited for plasma simulation, giving the chance to get a better basic understanding of the underlying physics. The simulation demonstrates the importance of a self-consistent neutral-plasma description to understand the effect of heat flux reduction
Solutioin of Poisson's Equation in Electrostatic Particle-on-cell Simulation
In electrostatic Particle-in-Cell simulations of the HEMP-DM3a ion thruster the role of different solution strategies for Poisson?s equation was investigated. The direct solution method of LU decomposition is compared to a stationary iterative method, the successive over-relaxation solver. Results and runtime of solvers were compared, and an outlook on further improvements and developments is presented
Influence of Electron Sources on the Near-field Plume in a Multistage Plasma Thruster
n order to obtain a better understanding of the near-field plume of a multistage plasma thruster, the influence of an external electron source is investigated by Particle-In-Cell simulations. The variation of the source position showed a strong influence of the magnetic field configuration on the electron distribution and therefore on the plume plasma. In the second part of this work, higher energetic electrons were injected in order to model collision-induced diffusion in the plume. This broadens the electron distribution, which leads to a more pronounced divergence angle in the angular ion distribution
Valoración antropométrica y nutricional de estudiantes de Nutrición de la Universidad Maza
Siendo la obesidad la
pandemia del siglo XXI, es necesario
analizar cuál es la incidencia de la misma
en personas especializadas en la temá-
tica, de ahí la importancia de evaluar su
prevalencia en estudiantes de Nutrición.
Su objetivo es determinar la composición y peso corporal
de alumnas de la carrera de Nutrición de la UMaza
Ingesta de hierro, vitamina A y C, en mujeres
El hierro es un
elemento esencial para la fisiología humana normal, ya que cumple funciones vitales. Su carencia se relaciona con anemia. El bajo consumo de hierro es una de las carencias nutricionales más importantes a nivel mundial, dado que afecta a países desarrollados y en vías en desarrollo.
Argentina no es ajena a esta problemátic
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