Unsteady State
Mostrando 1-12 de 44 artigos, teses e dissertações.
-
1. Effects of Macrosegregation and Microstructure on the Corrosion Resistance and Hardness of a Directionally Solidified Zn-5.0wt.%Mg Alloy
This study aims to analyze the influence of macrosegregation on microstructure evolution, and of microstructure length scale on the corrosion resistance of a Zn-5.0wt.%Mg alloy casting. The analyzed samples were taken along the length of castings unidirectionally solidified in unsteady state conditions of heat extraction. Microstructure characterization, mic
Mat. Res.. Publicado em: 05/09/2019
-
2. Longitudinal Aerodynamic and Stability Characteristics of High-Aspect-Ratio Unmanned Aerial Vehicles in Gust Response
ABSTRACT The aim of this work is to propose an accurate and reliable numerical simulation method of gust response, so as to analyze longitudinal stability characteristics of high-aspect-ratio unmanned aerial vehicles (UAVs) under gust response. Based on the dual-time stepping method, the unsteady Navies-Stokes equation was solved. By introducing grid velocit
J. Aerosp. Technol. Manag.. Publicado em: 03/06/2019
-
3. Relationship Between Aluminum-Rich/Intermetallic Phases and Microhardness of a Horizontally Solidified AlSiMgFe Alloy
An experimental study with an A356-AlSiMgFe alloy was developed to evaluate the microhardness performance in the microstructure resulting of an unsteady-state horizontal solidification process. The Al-7wt%Si-0.3wt%Mg-0.15wt%Fe alloy was elaborated and directionally solidified in a water-cooled horizontal solidification device. In order to experimentally dete
Mat. Res.. Publicado em: 23/11/2018
-
4. Transient Unidirectional Solidification, Microstructure and Intermetallics in Sn-Ni Alloys
The present research work examines the microstructural arrangements formed during the transient solidification of eutectic Sn-0.2wt.%Ni and hypereutectic Sn-0.5wt.%Ni alloys. Also, it examines their respective correlations with solidification thermal parameters: eutectic growth rate (VE) and eutectic cooling rate (ṪE); length scales of matrix and eutectic
Mat. Res.. Publicado em: 12/04/2018
-
5. Experimental Investigation of Ternary Al-Si-Cu Alloy Solidified with Unsteady-State Heat Flow Conditions
Ternary Al-9.0wt%Si-4.0wt%Cu alloy was solidified in a vertical directional solidification system under unsteady-state heat flow conditions. The resulting dendritic morphology and microsegregation were investigated. A more detailed analysis was dedicated to the microsegregation phenomena where a multielement interaction was observed. The solidification param
Mat. Res.. Publicado em: 12/03/2018
-
6. Performance and Wake Analysis of Rotors in Axial Flight Using Computational Fluid Dynamics
ABSTRACT: Flow field around rotors in axial flight is known to be complex especially in steep descent where the rotor is operating inside its own wake. It is often reported that, in this flight condition, the rotor is susceptible to severe wake interactions causing unsteady blade load, severe vibration, loss of performance, as well as poor control and handli
J. Aerosp. Technol. Manag.. Publicado em: 2017-06
-
7. The impact of convective drying on the color, phenolic content and antioxidant capacity of noni (Morinda citrifolia L.)
Abstract The effect of thin-layer drying temperature on color, phenolic content and antioxidant capacity of noni slices was investigated. Noni slices were air-dried at 50, 60 and 70 °C under natural convection conditions. Drying curves were fitted to thin-layer drying models in order to evaluate the drying characteristics of the product. In addition, an uns
Food Sci. Technol. Publicado em: 08/12/2016
-
8. Influence of upward and horizontal growth direction on microstructure and microhardness of an unsteady-state directionally solidified Al-Cu-Si alloy
In order to analyze the effect of the growth direction on dendrite arm spacing (λ1) and microhardness (HV) during horizontal directional solidification (HDS), experiments were carried out with the Al-3wt.%Cu-5.5wt.%Si alloy and the results compared with others from the literature elaborated for upward directional solidification (UDS). For this purpose, a wa
Matéria (Rio J.). Publicado em: 2016-03
-
9. Fouling behavior and performance of microfiltration membranes for whey treatment in steady and unsteady-state conditions
Whey pretreatment for protein purification is one of the main applications of cross-flow microfiltration before an ultrafiltration process. In this paper, the effects of the operating pressure and crossflow velocity on the membrane performance and the individual resistances in microfiltration of whey for both unsteady and steady-state conditions were investi
Braz. J. Chem. Eng.. Publicado em: 2014-06
-
10. The columnar to equiaxed transition of horizontal unsteady-state directionally solidified Al-Si alloys
Experiments were conducted to investigate the influence of thermal parameters on the columnar to equiaxed transition during the horizontal unsteady-state directional solidification of Al-Si alloys. The parameters analyzed include the heat transfer coefficients, growth rates, cooling rates, temperature gradients and composition. A combined theoretical and exp
Mat. Res.. Publicado em: 18/02/2014
-
11. Characterization of the Al-3wt.%Si alloy in unsteady-state horizontal directional solidification
The main purpose of this paper is to investigate both the columnar to equiaxed transition and primary dendritic arm spacings of Al-3wt.%Si alloy during the horizontal directional solidification. The transient heat transfer coefficient at the metal-mold interface is calculated based on comparisons between the experimental thermal profiles in castings and the
Mat. Res.. Publicado em: 14/05/2013
-
12. Aeroelastic stability analysis using linear matrix inequalities
The present work describes an alternative methodology for identification of aeroelastic stability in a range of varying parameters. Analysis is performed in time domain based on Lyapunov stability and solved by convex optimization algorithms. The theory is outlined and simulations are carried out on a benchmark system to illustrate the method. The classical
J. Braz. Soc. Mech. Sci. & Eng.. Publicado em: 2012