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A reading of the book of Wisdom leaves one with the impression of having listened to a splendid oratorio. The musical image of chapter 19, with some technical precision, confirms this impression. In fact, this poetic work of 502 verses, enveloped in mystery about its authorship and debate about its date of composition, is replete with sentiments of wonder before the harmony of the works of God. This paper is part of a broader study that seeks to describe the evolution of the author's discourse with regard to the composition history of the sections making up the book. For each section there is an attempt to grasp the interpretative implications of the literary analysis. The current article concentrates on the third part of the book, the sunkrisis. [ABSTRACT FROM AUTHOR]

A reading of the book of Wisdom leaves one with the impression of having listened to a splendid oratorio. The musical image of chapter 19, with some technical precision, confirms this impression. In fact, this poetic work of 502 verses, enveloped in mystery about its authorship and debate about its date of composition, is replete with sentiments of wonder before the harmony of the works of God. This paper is part of a broader study that seeks to describe the evolution of the author's discourse with regard to the composition history of the sections making up the book. For each section there is an attempt to grasp the interpretative implications of the literary analysis. The current article concentrates on the third part of the book, the sunkrisis. [ABSTRACT FROM AUTHOR]

In this work, a review of the theoretical aspects and an assessment to validate a Computational Fluid Dynamics (CFD) opensource code for applications in aerospace problems are discussed. !e code uses a "nite volume method, with cell-centered implementation, and it is suitable for simulations of inviscid, laminar, and turbulent #ows. !e code considers two-dimensional cases with unstructured meshes and employs the turbulence model known as Spalart-Allmaras. !e implementation is detailed presenting the spatial discretization, including the upwind scheme, the linear reconstruction algorithm, and the calculation applying the method of gradients. !e temporal discretization considers the application of a multistage explicit algorithm using a 5 stages Runge-Kutta method. !e validation was done considering three cases of study: the inviscid shock tube, the laminar #at plate, and the #ow over a rocket fairing. !ese cases are simulated using the so$ware developed and the results are compared with analytical and experimental results. !e rocket fairing case is related to the analysis of the Brazilian VLS launch during its transonic #ight and it exempli"es the e%ect of the shock wave/boundary-layer interaction in its pressure distribution. !e simulation results present a good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

This work presents a self-consistent optimization of multi-quantum well based nanostructured semiconductors. A Genetic Algorithm is used for the search module. The simulation module is based on the self-consistent solution of the coupled Poisson and Schrödinger equations by using the finite-element method. The results of two case tests are presented and discussed. [ABSTRACT FROM AUTHOR]

Self-consistent calculations of multi-quantum well semiconductor structures based on a Finite-Element Method are presented. The self-consistent calculation is specially needed when wells of different width are present in the structure, generating a larger charge separation and affecting significantly the tunneling conditions. The object-oriented computer code used was implemented using a finite-element class library developed and used in previous works. Results for an asymmetric heterostructure with a larger well and contact layers are also presented. [ABSTRACT FROM AUTHOR]

Presents information on a study which describes a MATHEMATICA notebook to compute the elements of the matrices which arise in the solution of the Helmholtz equation by the finite element method for tetrahedral elements of any approximation order. Methodology of the study; Results; Conclusions.

Focuses on the modal analysis of anisotropic diffused-channel waveguide by means of a scalar finite element method. Properties of annealed proton-exchange (APE) guides; Details on the finite element model; Information on the refractive index model.

Multi-objective optimization of a hypersonic airbreathing engine (scramjet technology) was carried out with the aim of maximizing thrust and minimizing drag while satisfying a series of design constraints, such as avoiding unstart (blockage of supersonic flow within the combustion chamber) by ensuring that the pressure ratio across the shock waves remains below the adverse pressure gradient given by the Korkegi limit, geometry correction to achieve shock on-lip condition, and temperature and pressure requirements at the inlet exit. Using the relations presented in the literature, pressure and viscous drag are estimated analytically. The analytical approach is verified against computational fluid dynamics data from Ansys Fluent to solve two-dimensional compressible Reynolds-averaged Navier–Stokes flow equations, with transition shear stress transport as the turbulence closure model. Comparing the total drag and the flow properties at the combustion chamber entrance shows the model's feasibility for the optimization approach. Three different approaches were conducted to formulate the multi-objective function to determine the one that can find the highest number of geometries satisfying the Korkegi limit with the highest net thrust. The best approach was the multi-objective function formulated with the uninstalled thrust, total pressure recovery, and pressure drag, concentrating the search in the region with greater uninstalled thrust and lower drag and nearly doubling the value of net thrust compared to the first formulation, which uses the uninstalled thrust, pressure drag, and viscous drag. [ABSTRACT FROM AUTHOR]

Electrostatic or capacitive accelerometers are among the highest volume microelectromechanical systems (MEMS) products nowadays. The design of such devices is a complex task, since they depend on many performance requirements, which are often conflicting. Therefore, optimization techniques are often used in the design stage of these MEMS devices. Because of problems with reliability, the technology of MEMS is not yet well established. Thus, in this work, size optimization is combined with the reliability-based design optimization (RBDO) method to improve the performance of accelerometers. To account for uncertainties in the dimensions and material properties of these devices, the first order reliability method is applied to calculate the probabilities involved in the RBDO formulation. Practical examples of bulk-type capacitive accelerometer designs are presented and discussed to evaluate the potential of the implemented RBDO solver. [ABSTRACT FROM AUTHOR]

In this paper, a model to calculate the dark current of quantum well infrared photodetectors at high-temperature regime is presented. The model is derived from a positive-definite quantum probability-flux and considers thermionic emission and thermally-assisted tunnelling as mechanisms of dark current generation. Its main input data are the wave functions obtained by time-independent Schrodinger equation and it does not require empirical parameters related to the transport of carriers. By means of this model, the dark current of quantum well infrared photodetectors at high-temperature regime is investigated with respect to the temperature, the barrier width, the applied electric field and the position of the first excited state. The theoretical results are compared with experimental data obtained from lattice-matched InAlAs/InGaAs, InGaAsP/InP on InP substrate and AlGaAs/GaAs structures with rectangular wells and symmetric barriers, whose absorption peak wavelengths range from MWIR to VLWIR. The corresponding results are in a good agreement with experimental data at different temperatures and at a wide range of applied electric field. [ABSTRACT FROM AUTHOR]

Focuses on a study which presented a procedure to select the best permanent magnets for periodic magnetic structures. Fundamentals of characterization method; Experimental procedure; Validation of the method.

This work describes an optical device for the simultaneous recording of shadowgrams and schlieren images, and some results are presented concerning its applications to the study of plasma assisted flow control in airfoil models. This approach offers many advantages in comparison to other methods, specially because the use of tracer particles (like smoke in wind tunnels) is not required for the experiments, thus avoiding contaminations in the electric discharges or air flows. Besides, while schlieren images reveal the refractive index gradients in the area of study, shadowgrams detect the second order spatial derivatives of the refractive indexes. Therefore, the simultaneous recording of these different images may give interesting information about the phenomena under study. In this paper, these images were used to confirm the existence of vortex structures in the flow induced by corona discharges on airfoil models. These structures are a possible explanation for the effects of drag reduction and lift force increasing, which have been reported in experiments of plasma assisted Aerodynamics. [ABSTRACT FROM AUTHOR]

• Differences on low temperature I–Vs of QWIP devices fabricated on the same wafer. • Low temperature transport mechanisms in superlattices with extremely large barriers. • A not conventional interpretation of C–V measurements on QWIP. Capacitance versus voltage, C–V, measurements are used to identify the origin of the difference between current versus voltage, I–V, characteristics of quantum well infrared photodetector, QWIP, devices fabricated simultaneously on the same wafer, i.e., same epitaxial layers. The devices have similar I–V curves at low bias but differ significantly at higher voltages. It is shown that the charge buildup inside the multiple quantum well structure is responsible for changing the conduction mechanism at voltages lower than that would be expected if the entire structure was subjected to a uniform electric field. This charge buildup varies from device to device, indicating local characteristics dependence. Although a non-uniform electric field is established, as identified by C–V measurements, none of the known fingerprints related to the formation and propagation of electric field domains are present in the I–V curves, i.e., no plateau or negative differential conductivity were observed. [ABSTRACT FROM AUTHOR]