Engineering Commons^™

Detection Of An So2 Plume Over Sapporo, Japan From The Eruption Of Mt. Kasatochi Using A Balloon Sounding Technique, Gary A. Morris, Jun Hirokawa, Masatomo Fujiwara, Fumio Hasebe, Keisuke Ishida, Nicholay Krotkov, Mark R. Schoeberl, Walter Komhyr, Barry Lefer, James Flynn

Gary A. Morris

During the month of August 2008, 10 ozonesondes were launched from Hokkaido University in Sapporo, Japan as part of a study to examine regional pollution during the Olympic period. Seven of these soundings included a second instrument with a filter designed to remove SO2 from the intake air stream. SO2 interferes with the normal chemistry of the electrochemical cell (ECC) method for ozone detection, with the net result being that each molecule of SO2 registers as minus one molecule of O3. Thus the unfiltered sonde reports [O3] - [SO2] while the filtered sonde reports [O3]. Laboratory tests prior to launch …

Homogeneous Dbd In N2: 1) Lif, Talif And Electrical Measurements, N. Gherardi, Et. Es-Sebbar, C. Sarra-Bourret, N. Naudé, F. Massines

Dr. Et-touhami Es-sebbar

In this paper we compare two different discharges that can be obtained in a DBD configuration, that is to say the filamentary discharge (usual regime in atmospheric DBD) with the Atmospheric Pressure Townsend Discharge (APTD), which is a homogeneous regime obtained in nitrogen atmosphere. The aim is to help in the understanding of the processes which control the transition from one regime to the other. To do so, the discharge is characterized through electrical measurements, coupled with optical diagnostics among which Laser Induced Fluorescence (LIF) for radical density measurements. The influence of the addition of small quantities of additives on …

Active Species Generation Of Homogeneous Dbd In N2: Experiment And Modelling, N. Gherardi, Et. Es-Sebbar, C. Sarra-Bourret, N. Naudé, F. Massines, D. Tzyganov, P. Ségur, S. Pancheshnyi

Dr. Et-touhami Es-sebbar

No abstract provided.

Investigation Of Stun Guns As Intentional Electromagnetic Interference (Emi) Sources, George H. Baker, Ryan C. Tuttle

George H Baker

Because the operation and control of most critical infrastructures are highly dependent on electronics, it is important to understand the vulnerability of those electronics to intentional electromagnetic interference (EMI). The possibility of interference using readily available consumer devices is a particular concern. We investigated the feasibility and effectiveness of using compact stun guns to intentionally interfere with electronic systems. Test articles included individual computers and computers networked through a central hub. 60KV and 600KV devices were used in the experiments. Results indicate that stun guns are effective in disabling digital electronic systems.

Surface Ion-Electron Recombination As The Main Source Of Atoms In Flowing N2 Dbd, D. Tsyganov, Et. Es-Sebbar, S. Pancheshnyi, N. Gherardi, P. Ségur, F. Massines

Dr. Et-touhami Es-sebbar

No abstract provided.

Talif Quantification Of Nitrogen Atoms Applied To Experimental Simulation Of Titan’S Atmosphere, Et. Es-Sebbar, Y. Benilan, E. Arzoumanian, M.-C. Gazeau

Dr. Et-touhami Es-sebbar

No abstract provided.

S.E.T.U.P., A New Program Of Representative Simulations Of Titan’S Atmosphere: Current Status, M-C. Gazeau, E. Arzoumanian, Y. Benilan, Et. Es-Sebbar, A. Jolly, S. Perrier, C. Romanzin

Dr. Et-touhami Es-sebbar

No abstract provided.

Report Of The Commission To Assess The Threat To The United States From Emp Attack: Critical National Infrastructures, William R. Graham

George H Baker

The physical and social fabric of the United States is sustained by a system of systems; a complex and dynamic network of interlocking and interdependent infrastructures (“critical national infrastructures”) whose harmonious functioning enables the myriad actions, transactions, and information flow that undergird the orderly conduct of civil society in this country. The vulnerability of these frastructures to threats — deliberate, accidental, and acts of nature — is the focus of greatly heightened concern in the current era, a process accelerated by the events of 9/11 and recent hurricanes, including Katrina and Rita. This report presents the results of the Commission’s …

Comparison Of Townsend Dielectric Barrier Discharge In N2, N2/O2 And N2/N2o: Behavior And Density Of Radicals, F. Massines, Et. Es-Sebbar, N. Gherardi, N. Naudé, D. Tsyganov, P. Ségur, S. Pancheshnyi

Dr. Et-touhami Es-sebbar

No abstract provided.

Dielectric Relaxation Behaviour Of Glycine In Acqueous Solution Medium In The Microwave Frequency Region, Ajaya Kumar Kavala

Mr Ajaya Kumar Kavala

No abstract provided.

Quantum Transport In In0.75Ga0.25As Quantum Wires, P. J. Simmonds, F. Sfigakis, H. E. Beere, D. A. Ritchie, M. Pepper, D. Anderson, G. A.C. Jones

Paul J. Simmonds

In addition to quantized conductance plateaus at integer multiples of 2e²/h, the differential conductance G=dI/dV shows plateaus at 0.25(2e²/h) and 0.75(2e²/h) under applied source-drain bias in In_0.75Ga_0.25As quantum wires defined by insulated split gates. This observation is consistent with a spin-gap model for the 0.7 structure. Using a tilted magnetic field to induce Landau level crossings, the g factor was measured to be ~9 by the coincidence method. This material, with a mobility of 1.8×10⁵ cm …

Low-Energy Antiphase Boundaries, Degenerate Superstructures, And Phase Stability In Frustrated Fcc Ising Model And Ag-Au Alloys, Nikolai A. Zarkevich, Teck L. Tan, Lin-Lin Wang, Duane D. Johnson

Duane D. Johnson

An Ising model exhibits zero-energy antiphase boundaries (APBs) and frustration on close-packed face-centered cubic (fcc) and triangular lattices. The frustration results in degenerate structures and chains of long-period superstructures forming a quasicontinuous ground-state “hull” in the formation energy versus composition (c) diagram. In alloys, a nonzero but small APB energy yields a c-dependent reduction in this degeneracy that affects the phase diagram topology and range of the two-phase coexistence. Using density functional theory combined with cluster expansions (CEs), we study Ag-Au alloys as a prototype and find the effective cluster interactions (dominated by nearest-neighbor pairs), predict energetics of millions of …

Laboratory Experiments As Support To The Built Up Of Titan’S Theoretical Models And Interpretation Of Cassini-Huygens Data, M-C. Gazeau, Y Benilan, Et. Es-Sebbar, T. Ferradaz, E. Hébrard, A. Jolly, F. Raulin, C. Romanzin, J-C. Guillemin, C. Berteloite, A. Canosa, S. D. Le Picard, Ian R. Sims

Dr. Et-touhami Es-sebbar

No abstract provided.

Grain Growth And Texture Development In Lithium Fluoride Thin Films, Hakkwan Kim, Alexander H. King

Alexander H. King

We have studied grain-growth and texture development in polycrystalline lithium fluoride thin films using dark-field transmission electron microscopy. We demonstrate that we can isolate the size distribution of 〈111〉 surface normal grains from the overall size distribution, based on simple and plausible assumptions about the texture. The {111} texture formation and surface morphology were also observed by x-ray diffraction and atomic force microscopy, respectively. The grain-size distributions become clearly bimodal as the annealing time increases, and we deduce that the short-time size distributions are also a sum of two overlapping peaks. The smaller grain-size peak in the distribution corresponds to …

Predicting Enthalpies Of Molecular Substances: Application To Libh4, Nikolai A. Zarkevich, Duane D. Johnson

Duane D. Johnson

For molecular substances exhibiting harmonic and nonharmonic vibrations, we present a first-principles approach to predict enthalpy differences between phases at finite temperatures, including solid-solid and melting. We apply it to the complex hydride LiBH4. Using ab initio molecular dynamics, we predict a structure for the high-T solid phase of lithium borohydride, and we propose an approximation to account for nonharmonic vibrations. We then predict the enthalpy changes for solid-solid transition, melting, and an H-storage reaction, all in agreement with experiment.

Charge Transfer Mechanisms In Electrospinning, Jonathan J. Stanger

Jonathan J Stanger

Electrospinning is a method of producing nano structured material from a polymer solution or melt using high strength electric fields. It is a process that has yet to find extensive industrial application yet shows promise if obstacles such as low rate of production overcome perhaps by more complete theoretical modelling. This work examines the effects of adding an ionic salt to a solution of poly(vinyl alcohol) in water. The direct effect was an increase the charge density and electric current. It was found that an increase in charge density decreases the mass deposition rate and forms a thinner initial jet. …

Modeling Of Dispersed Phase By Lagrangian Approach In Fluent - 2d Exercise, Kari Myöhänen

Kari Myöhänen

This shows an example calculation applying DPM model in Fluent. This is related to the other DPM presentation and was prepared for the course 'Theory and simulation of dispersed-phase multiphase flows" by Dr. Payman Jalali, Lappeenranta University of Technology.

Modeling Of Dispersed Phase By Lagrangian Approach In Fluent, Kari Myöhänen

Kari Myöhänen

This is a seminar work prepared for a course 'Theory and simulation of dispersed-phase multiphase flows' by Dr. Payman Jalali, Lappeenranta University of Technology

Morphologies And Kinetics Of A Dewetting Ultrathin Solid Film, Mikhail Khenner

Mikhail Khenner

The surface evolution model based on geometric partial differential equation is used to numerically study the kinetics of dewetting and dynamic morphologies for the localized pinhole defect in the surface of the ultrathin solid film with the strongly anisotropic surface energy. Depending on parameters such as the initial depth and width of the pinole, the strength of the attractive substrate potential and the strength of the surface energy anisotropy, the pinhole may either extend to the substrate and thus rupture the film, or evolve to the quasiequilibrium shape while the rest of the film surface undergoes phase separation into a …

Enhanced Stability Of A Dewetting Thin Liquid Film In A Single-Frequency Vibration Field, Sergey Shklyaev, Mikhail Khenner, Alexei Alabuzhev

Mikhail Khenner

Dynamics of a thin dewetting liquid film on a vertically oscillating substrate is considered. We assume moderate vibration frequency and large (compared to the mean film thickness) vibration amplitude. Using the lubrication approximation and the averaging method, we formulate the coupled sets of equations governing the pulsatile and the averaged fluid flows in the film, and then derive the nonlinear amplitude equation for the averaged film thickness. We show that there exists a window in the frequency-amplitude domain where the parametric and shear-flow instabilities of the pulsatile flow do not emerge. As a consequence, in this window the averaged description …

Cascading Infrastructure Failures: Avoidance And Response, George H. Baker, Cheryl J. Elliott

George H Baker

No critical infrastructure is self-sufficient. The complexity inherent in the interdependent nature of infrastructure systems complicates planning and preparedness for system failures. Recent wide-scale disruption of infrastructure on the Gulf Coast due to weather, and in the Northeast due to electric power network failures, dramatically illustrate the problems associated with mitigating cascading effects and responding to cascading infrastructure failures once they have occurred.

The major challenge associated with preparedness for cascading failures is that they transcend system, corporate, and political boundaries and necessitate coordination among multiple, disparate experts and authorities. This symposium brought together concerned communities including government and industry …