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Radiation Exposure During Space Travel: Using Radioisotopes For A Comparative Study Of Human Feces And Urine As Integrated Shield Components, Noah L. Falck 2017 California Polytechnic State University, San Luis Obispo

Radiation Exposure During Space Travel: Using Radioisotopes For A Comparative Study Of Human Feces And Urine As Integrated Shield Components, Noah L. Falck

Symposium

Earth’s atmosphere and magnetosphere deflect and absorb the majority of harmful radiation traversing Space; however, once outside Low Earth Orbit (LEO), payloads are exposed to Galactic Cosmic Rays (GCR) and Solar Particle Events (SPEs). While humans possess capabilities that hardware does not, we are uniquely vulnerable to radiation. Detrimental effects range from nausea and dizziness brought by intense, short term doses to increased cancer risk and impaired cognitive function associated with chronic exposure. This paper aims to explore the use of human waste (feces and urine) as radiation shields in a comparative study of urine v. water and hydrated ...


A Dual-Potential Formulation Of The Navier-Stokes Equations , Steven Gerard Gegg 2017 Iowa State University

A Dual-Potential Formulation Of The Navier-Stokes Equations , Steven Gerard Gegg

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A dual potential formulation for numerically solving the Navier-Stokes equations is developed and presented. The velocity field is decomposed using a scalar and vector potential. Vorticity and dilatation are used as the dependent variables in the momentum equations. Test cases in two dimensions verify the capability to solve flows using approximations from potential flow to full Navier-Stokes simulations. A three-dimensional incompressible flow formulation is also described;An interesting feature of this approach to solving the Navier-Stokes equations is the decomposition of the velocity field into a rotational part (vector potential) and an irrotational part (scalar potential). The Helmholtz decomposition theorem ...


Heat Transfer Analysis Of Localized Heat-Treatment For Grade 91 Steel, Jacob D. Walker 2017 Utah State University

Heat Transfer Analysis Of Localized Heat-Treatment For Grade 91 Steel, Jacob D. Walker

All Graduate Theses and Dissertations

Many of the projects utilizing Grade 91 steel are large in scale, therefore it is necessary to assemble on site. The assembly of the major pieces often requires welding in the assembly; welding drastically changes the superior mechanical properties of Grade 91 steel that it was specifically developed for. Therefore, because of the adverse effects of welding on the mechanical properties of Grade 91, it is necessary to do a localized post weld heat treatment.

In this study a localized post weld heat treatment is used to gather experimental data. The data is then used to derive unknown heat transfer ...


Graduated Stress Exposure Of Spaceflight Hazards In A Virtual Environment, Tor Finseth, Nir Keren, Warren D. Franke, Michael C. Dorneich, Clayton C. Anderson 2017 Iowa State University

Graduated Stress Exposure Of Spaceflight Hazards In A Virtual Environment, Tor Finseth, Nir Keren, Warren D. Franke, Michael C. Dorneich, Clayton C. Anderson

Warren D Franke

Stress experienced by astronauts during high-level hazardous situations may poses risk to personnel wellbeing and to mission success. Stress inoculation training (SIT) provides individuals with experience of minor stressors and coping skills during non-critical times to enhance their resistance to stress. This study evaluates the effect of exposure to a low level stressor on physiological response and cognitive load in high level stressor setting. Simulation of fire emergency on the International Space Station (ISS) in a full-scale, immersive, interactive, 3D virtual reality environment facilitated a process for stress inoculation. The experimental settings included two groups that have been exposed to ...


Phase Field Approach To Martensitic Phase Transformations With Large Strains And Interface Stresses, Valery I. Levitas 2017 Iowa State University

Phase Field Approach To Martensitic Phase Transformations With Large Strains And Interface Stresses, Valery I. Levitas

Valery I. Levitas

Thermodynamically consistent phase field theory for multivariant martensitic transformations, which includes large strains and interface stresses, is developed. Theory is formulated in a way that some geometrically nonlinear terms do not disappear in the geometrically linear limit, which in particular allowed us to introduce the expression for the interface stresses consistent with the sharp interface approach. Namely, for the propagating nonequilibrium interface, a structural part of the interface Cauchy stresses reduces to a biaxial tension with the magnitude equal to the temperature-dependent interface energy. Additional elastic and viscous contributions to the interface stresses do not require separate constitutive equations and ...


Size And Mechanics Effects In Surface-Induced Melting Of Nanoparticles, Valery I. Levitas, Kamran Samani 2017 Iowa State University

Size And Mechanics Effects In Surface-Induced Melting Of Nanoparticles, Valery I. Levitas, Kamran Samani

Valery I. Levitas

Various melting-related phenomena (like surface melting, size dependence of melting temperature, melting of few nm-size particles and overheating at a very fast heating rate) are of great fundamental and applied interest, although the corresponding theory is still lacking. Here we develop an advanced phase-field theory of melting coupled to mechanics, which resolves numerous existing contradictions and allowed us to reveal exciting features of melting problems. The necessity of introducing an unexpected concept, namely, coherent solid-melt interface with uniaxial transformation strain, is demonstrated. A crossover in temperature dependence of interface energy for radii below 20 nm is found. Surface-induced premelting and ...


Influence Of Aluminum Passivation On The Reaction Mechanism: Flame Propagation Studies, Birce Dikici, Steven W. Dean, Michelle L. Pantoya, Valery I. Levitas, R. Jason Jouet 2017 Texas Tech University

Influence Of Aluminum Passivation On The Reaction Mechanism: Flame Propagation Studies, Birce Dikici, Steven W. Dean, Michelle L. Pantoya, Valery I. Levitas, R. Jason Jouet

Valery I. Levitas

Currently, two main known mechanisms of aluminum (Al) nanoparticle reaction are discussed in the literature, namely those based on diffusion through an oxide shell and melt-dispersion. The two mechanisms lead to opposite predictions in nanoparticle design. The diffusion mechanism suggests that the reduction or complete elimination of the oxide shell will increase Al reactivity, whereas the meltdispersion mechanism suggests an increase in initial oxide thickness up to an optimal value. The goal of this study is to perform critical experiments in a confined flame tube apparatus to compare these two predictions. Specifically, the flame propagation rates of perfluoroalkyl carboxylic acid ...


Coupled Phase Transformations And Plastic Flows Under Torsion At High Pressure In Rotational Diamond Anvil Cell: Effect Of Contact Sliding, Biao Feng, Valery I. Levitas 2017 Iowa State University

Coupled Phase Transformations And Plastic Flows Under Torsion At High Pressure In Rotational Diamond Anvil Cell: Effect Of Contact Sliding, Biao Feng, Valery I. Levitas

Valery I. Levitas

A three-dimensional large-sliding contact model coupled with strain-induced phase transformations (PTs) and plastic flow in a disk-like sample under torsion at high pressure in rotational diamond anvil cell (RDAC) is formulated and studied. Coulomb and plastic friction are combined and take into account variable parameters due to PT. Results are obtained for weaker, equal-strength, and stronger high pressure phases, and for three values of the kinetic coefficient in a strain-controlled kinetic equation and friction coefficient. All drawbacks typical of problem with cohesion are overcome, including eliminating mesh-dependent shear band and artificial plastic zones. Contact sliding intensifies radial plastic flow, which ...


Sublimation Via Virtual Melting Inside An Elastoplastic Material, Valery I. Levitas, Nataliya Altukhova 2017 Iowa State University

Sublimation Via Virtual Melting Inside An Elastoplastic Material, Valery I. Levitas, Nataliya Altukhova

Valery I. Levitas

Thermodynamic, kinetic, and mechanical approaches for sublimation inside elastoplastic material via intermediate (virtual) melting under tensile pressure are developed for a spherical nucleus. Virtual melting represents the appearance of subcritical liquid drop that immediately transforms to gas bubble. The variety of mechanisms and transformation paths are revealed in different pressure ranges. The radius of the critical gas nucleus differs from the classical one because elastic energy of melt is size dependent due to surface tension. Our developed approach can be extended for various structural changes in nanoparticles within a void inside elastoplastic material and two-stage and multistage nucleation processes. Universal ...


Experimental Data Analysis Of The Vortex Structures In The Wakes Of Flapping Wings, Kai Wang, Umesh Vaidya, Baskar Ganapathysubramanian, Hui Hu 2017 Iowa State University

Experimental Data Analysis Of The Vortex Structures In The Wakes Of Flapping Wings, Kai Wang, Umesh Vaidya, Baskar Ganapathysubramanian, Hui Hu

Umesh Vaidya

The objective of this paper is to compare the existing methods and develop novel approaches for the experimental data analysis of the unsteady aerodynamics of the flapping wing microaerial-vehicle. These methods are developed for the purpose of identification of the beneficial dynamics and for the development of reduced order models for control design. We first employ Proper Orthogonal Decomposition (POD) method for the data analysis of the PIV measurements in the wakes of piezoelectric flapping wings. The basic idea behind POD based data analysis method is to decompose the time series snapshots of PIV measurements into high energy, POD, modes ...


Experimental Data Analysis Of The Vortex Structures In The Wakes Of Flapping Wings, Kai Wang, Umesh Vaidya, Baskar Ganapathysubramanian, Hui Hu 2017 Iowa State University

Experimental Data Analysis Of The Vortex Structures In The Wakes Of Flapping Wings, Kai Wang, Umesh Vaidya, Baskar Ganapathysubramanian, Hui Hu

Baskar Ganapathysubramanian

The objective of this paper is to compare the existing methods and develop novel approaches for the experimental data analysis of the unsteady aerodynamics of the flapping wing microaerial-vehicle. These methods are developed for the purpose of identification of the beneficial dynamics and for the development of reduced order models for control design. We first employ Proper Orthogonal Decomposition (POD) method for the data analysis of the PIV measurements in the wakes of piezoelectric flapping wings. The basic idea behind POD based data analysis method is to decompose the time series snapshots of PIV measurements into high energy, POD, modes ...


Cruise Missile Integrated Air Defense System Penetration: Modeling The S-400 System, Michael Pelosi, Amie K. Honeycutt 2017 East Central University, Ada OK

Cruise Missile Integrated Air Defense System Penetration: Modeling The S-400 System, Michael Pelosi, Amie K. Honeycutt

International Journal of Aviation, Aeronautics, and Aerospace

This research determines improved flight-path routes that make maximum utilization of terrain-masking opportunities, and defending radar and missile system equipment performance and launch timing constraints, in order to avoid radar detection and tracking, and to mitigate subsequent missile shoot-down risks. The problem is formulated as one of constrained optimization in three dimensions. Advantageous solutions are identified using the A* Algorithm in conjunction with detailed equipment performance and constraint calculations and high-resolution digital terrain elevation maps. Topographical features in digital terrain are exploited by the algorithm to avoid radar detection and tracking. The model includes provisions for all-aspect/all-frequency radar cross ...


Design Of Orbital Maneuvers With Aeroassisted Cubesatellites, Stephanie Clark 2017 University of Arkansas, Fayetteville

Design Of Orbital Maneuvers With Aeroassisted Cubesatellites, Stephanie Clark

Stephanie Clark

Recent advances within the field of cube satellite technology has allowed for the possible development of a maneuver that utilizes a satellite's Low Earth Orbit (LEO) and increased atmospheric density to effectively use lift and drag to implement a noncoplanar orbital maneuver. Noncoplanar maneuvers typically require large quantities of propellant due to the large delta-v that is required. However, similar maneuvers using perturbing forces require little or no propellant to create the delta-v required. This research reported here studied on the effects of lift on orbital changes, those of noncoplanar types in particular, for small satellites without orbital maneuvering ...


Turbulent Combustion Of Polydisperse Evaporating Sprays With Droplet Crossing: Eulerian Modeling And Validation In The Infinite Knudsen Limit, S. de Chaisemartin, L. Freret, D. Kah, F. Laurent, Rodney O. Fox, J. Reveillon, M. Massot 2017 Ecole Centrale Paris

Turbulent Combustion Of Polydisperse Evaporating Sprays With Droplet Crossing: Eulerian Modeling And Validation In The Infinite Knudsen Limit, S. De Chaisemartin, L. Freret, D. Kah, F. Laurent, Rodney O. Fox, J. Reveillon, M. Massot

Rodney O. Fox

The accurate simulation of the dynamics of polydisperse evaporating sprays in unsteady gaseous flows with large-scale vortical structures is both a crucial issue for industrial applications and a challenge for modeling and scientific computing. The difficulties encountered by the usual Lagrangian approaches make the use of Eulerian models attractive, aiming at a lower cost and an easier coupling with the carrier gaseous phase. Among these models, the multi-fluid model allows for a detailed description of the polydispersity and size-velocity correlations for droplets of various sizes. The purpose of the present study is twofold. First, we extend the multi-fluid model in ...


Development Of High-Order Realizable Finite-Volume Schemes For Quadrature-Based Moment Method, Varun Vikas, Z. J. Wang, Alberto Passalacqua, Rodney O. Fox 2017 Iowa State University

Development Of High-Order Realizable Finite-Volume Schemes For Quadrature-Based Moment Method, Varun Vikas, Z. J. Wang, Alberto Passalacqua, Rodney O. Fox

Rodney O. Fox

Kinetic equations containing terms for spatial transport, gravity, fluid drag and particle-particle collisions can be used to model dilute gas-particle flows. However, the enormity of independent variables makes direct numerical simulation of these equations almost impossible for practical problems. A viable alternative is to reformulate the problem in terms of moments of velocity distribution. Recently, a quadrature-based moment method was derived by Fox for approximating solutions to kinetic equation for arbitrary Knudsen number. Fox also described 1st- and 2nd-order finite-volume schemes for solving the equations. The success of the new method is based on a moment-inversion algorithm that is used ...


Numerical Description Of Dilute Particle-Laden Flows By A Quadrature-Based Moment Method, N. Le Lostec, Rodney O. Fox, O. Simonin, P. Villedieu 2017 Office National d'Etudes et de Recherches Aerospatiales, France

Numerical Description Of Dilute Particle-Laden Flows By A Quadrature-Based Moment Method, N. Le Lostec, Rodney O. Fox, O. Simonin, P. Villedieu

Rodney O. Fox

The numerical simulation of gas-particle flows is divided into two families of methods. In Euler-Lagrange methods individual particle trajectories are computed, whereas in Euler-Euler methods particles are characterized by statistical descriptors. Lagrangian methods are very precise but their computational cost increases with instationarity and particle volume fraction. In Eulerian methods (also called moment methods) the particle-phase computational cost is comparable to that of the fluid phase but requires strong simplificaions. Existing Eulerian models consider unimodal or close-to-equilibrium particle velocity distributions and then fail when the actual distribution is far from equilibrium. Quadrature-based Eulerian methods introduce a new reconstruction of the ...


A Quadrature-Based Moment Closure For The Williams Spray Equation, O. Desjardins, Rodney O. Fox, P. Villedieu 2017 Iowa State University

A Quadrature-Based Moment Closure For The Williams Spray Equation, O. Desjardins, Rodney O. Fox, P. Villedieu

Rodney O. Fox

Sprays and other dispersed-phase systems can be described by a kinetic equation containing terms for spatial transport, acceleration, and particle processes (such as evaporation or collisions). In principle, the kinetic description is valid from the dilute (non-collisional) to the dense limit. However, its numerical solution in multi-dimensional systems is intractable due to the large number of independent variables. As an alternative, Lagrangian methods "discretize" the density function into "parcels" that are simulated using Monte-Carlo methods. While quite accurate, as in any statistical approach, Lagrangian methods require a relatively large number of parcels to control statistical noise, and thus are computationally ...


A Fully Coupled Fluid-Particle Flow Solver Using Quadrature-Based Moment Method With High-Order Realizable Schemes On Unstructured Grids, Varun Vikas, Z. J. Wang, Alberto Passalacqua, Rodney O. Fox 2017 Iowa State University

A Fully Coupled Fluid-Particle Flow Solver Using Quadrature-Based Moment Method With High-Order Realizable Schemes On Unstructured Grids, Varun Vikas, Z. J. Wang, Alberto Passalacqua, Rodney O. Fox

Rodney O. Fox

Kinetic Equations containing terms for spatial transport, gravity, fluid drag and particle-particle collisions can be used to model dilute gas-particle flows. However, the enormity of independent variables makes direct numerical simulation of these equations almost impossible for practical problems. A viable alternative is to reformulate the problem in terms of moments of the velocity distribution function. A quadrature method of moments (QMOM) was derived by Desjardins et al. [1] for approximating solutions to the kinetic equation for arbitrary Knudsen number. Fox [2, 13] derived a third-order QMOMfor dilute particle flows, including the effect of the fluid drag on the particles ...


Meso-Scale Imaging Of Composite Materials, Robert J. Grandin, Joseph N. Gray 2017 Iowa State University

Meso-Scale Imaging Of Composite Materials, Robert J. Grandin, Joseph N. Gray

Robert Grandin

The performance of composite materials is controlled by the interaction between the individual components as well as the mechanical characteristics of the components themselves. Geometric structure on the meso-scale, where the length-scales are of the same order as the material granularity, plays a key role in controlling material performance and having a quantitative means of characterizing this structure is crucial in developing our understanding of NDE technique signatures of early damage states. High-resolution computed tomography (HRCT) provides an imaging capability which can resolve these structures for many composite materials. Coupling HRCT with three-dimensional physics-based image processing enables quantitative characterization of ...


Beam Flattener Design For High-Energy Radiographic Inspection, Robert J. Grandin, Thomas J. Rudolphi 2017 NASA Marshall Space Flight Center,

Beam Flattener Design For High-Energy Radiographic Inspection, Robert J. Grandin, Thomas J. Rudolphi

Robert Grandin

This report documents the work done to develop a beam flattener for use in the inspection of rocket motors at ATK Space Systems Utah facilities. The following pages provide a brief introduction to the necessity of this project, comprehensive description of the design methodology, and experimentally-based conclusions regarding project success.


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