Dr. Ephraim Suhir
Portland State University,
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Short Note Volume 3 Issue 1
Abstract: The objective of the analysis is to demonstrate how the Boltzmann-Arrhenius-Zhurkov (BAZ) model, originally suggested by Zhurkov in the kinetic concept of the strength of solids as a generalization of the Arrhenius theory of chemical reactions, can be effectively employed for the prediction of the lifetime of electronic materials experiencing ionizing radiation. The "loading term" γσ in the original BAZ model, where σ is the tensile mechanical stress and γ is the sensitivity factor, is replaced with the term γRD, where D is the radiation level and γR is the sensitivity factor. Leakage current measured during the failure-oriented-accelerated-testing (FOAT) is considered in our analysis as a suitable indication/criterion of the level of the induced damage. FOAT terminates, when the agreed upon critical value of the leakage current is reached.
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Review Article Volume 3 Issue 1
Abstract: Box wing aircraft weight issues, structural interactions as well as inter-wing joint designs differ remarkably from Conventional Cantilever Wing configuration and present design challenges which have been extensively investigated by several researchers. This study discusses the results of such investigations in order to highlight the prospects of the Box-Wing aircraft as well as pending structural design challenges that require further examination.
Abstract: Aerodynamic Forces mainly lift and Drag acting on an aircraft, are directly related to the geometry and wing profile of an aircraft. In this research we first designed a blended wing UAV (using X48B as a baseline model) and then performed the CFD analysis. Focusing on the lift to drag ratio in Cruise conditions, we made changes to our initial design based on critical pressure regions found by simulation and afterwards improved our design to almost three times by making changes to the initial geometry.
Review Article Volume 2 Issue 1
Abstract: The atomic structure is presented on the basis of the theory of vortex gravitation. The feasibility and calculation of the values of the density and mass of electromagnetic particles are proposed. A calculation is made, which proves that the photon must have mass. In the calculations, some physical characteristics of electromagnetic particles that are accepted by modern physics are refuted.
Abstract: This review paper is based mostly on the author's recent publications and addresses the application of analytical ("mathematical") predictive modeling to understand the physics and mechanics of the behavior and performance of solder materials and solder joint interconnections employed in IC devices. The emphasis is on the design for reliability and, first of all, on the prediction of the thermal stresses and strains in solder joint interconnections of electronic products.
Original Research Article Volume 2 Issue 1
Abstract: A methodology to efficiently simulate wind tunnel tests of several airfoils with OpenFOAM has been developed in this work. This methodology bridges OpenFOAM capabilities with MATLAB post-processing in order to analyze efficiently the performance of wind turbine airfoils at any angle of attack. This technique has been developed to reduce the cost, in terms of time and resources, of wind tunnel campaigns on wind turbine blade airfoils.
Original Research Article Volume 1 Issue 2
Abstract: Flutter suppression of a typical airfoil with uncertain pitch stiffness by feedback control of its trailing-edge surface is analyzed. The pitch stiffness coefficient is modeled by a quadratic function of a bounded random variable with the bounded probability density function, thus the airfoil system becomes a stochastic structure depending on its random parameter.
Original Research Volume 1 Issue 2
Abstract: The importance of satisfying the Geometric Conservation Law (GCL) to maintain second-order temporal accuracy for flow evaluations on dynamic grids are investigated for a Finite Volume Method (FVM)-based dual-time stepping Unsteady Reynolds-Averaged Navier-Stokes (URANS) solver.
Research Article Volume 1 Issue 2
Abstract: Professionals within the aerospace industry are often required to remain within acoustic environments characterized by a predominance of low frequency and infrasound components. Safety-and-health-in-the-workplace officials are mindful of the threat these extreme environments can pose to the hearing function.
Abstract: Tensegrity systems are mechanical structures made of struts in compression, kept in stable equilibrium by a network of cables in tension, they are a class of mechanical structures which are highly controllable.
Abstract: The objective of this paper is to critically evaluate the accuracy and efficiency of a general-purpose micromechanics approach based on the Mechanics of Structure Genome (MSG), when it is applied to the constitutive modeling of 3D structures.
Research Article Volume 1 Issue 1
Abstract: This paper describes the nonlinear dynamics of planar tensegrity bridges designed for minimal mass. The three-dimensional bridge benefits by the planar analysis in the most important manner relating to topology of material. We start with the minimal mass bridge, counting both structural mass and deck mass, and then derive the nonlinear dynamics to study dynamic behavior of the minimal mass bridge.
Abstract: The present methodology describes a register system of ocular and head movements in a human gyroscope, whose purpose was to observe the behavior of the vestibulo-ocular reflex. Two stages compound the system: a video-oculography element, which quantifies eye movements.
Original Article Volume 1 Issue 1
Abstract: Numerical simulations are conducted on the DHC-6 Twin Otter wing and horizontal tailplane to explore the aerodynamic penalties that affect airfoil performance in heavy rain conditions. An Eulerian-Lagrangian two-phase flow method is used to simulate the aerodynamic performance of the wing under rainfall conditions.
Abstract: Large Eddy Simulation combined with an Eddy Dissipation Concept (EDC) combustion model shows the feasibility for simulations of a full scale aircraft immersed within a large aviation-fuel fire in a moving fluid medium. Coupling between the condensed fuel and gas phases allows investigating the roles of the wind speed on the burning rate of condensed fuel, and consequently, the heat release rate.
ORIGINAL ARTICLE Volume 1 Issue 1
Abstract: This paper presents a modified particle filter for SINS/SAR (Strap-down Inertial Navigation System/Synthetic Aperture Radar) integrated navigation. This method is developed by adopting Markov Chain Monte Carlo (MCMC) moves to the particle regularization process. It combines local resampling with MCMC moves to prevent particle degeneracy and also guarantee that the resultant particles are in the same distribution as probability distribution function, without causing extra noise on state estimate.
Abstract: This paper presents a new method to calculate the geometric dilution of precision (GDOP) of GPS by incorporating the concept of model predictive filtering in the training process of neural networks to learn the relationship between GDOP and the azimuth and elevation of satellite. This method overcomes the shortcomings of the traditional back propagation neural networks, such as the slow convergence speed and easily falling into local minimum.