Digital Commons Network^™

Electron Density And Electron Neutral Collision Frequency In The Ionosphere Using Plasma Impedance Probe Measurement, E. Spencer, S. Patra, T. Andriyas, C. Swenson, J. Ward, A. Barjatya

Publications

Swept Impedance Probe measurements in a sporadic E layer observed during the Sudden Atomic Layer (SAL) sounding rocket mission are analyzed to obtain absolute electron densities and electron neutral collision frequencies accurately. Three sets of upleg and downleg impedance data are selected for the analysis. Initial estimates of the plasma parameters are obtained through a least mean square fit of the measured impedance data against the analytical impedance formula ZB(f ) of Balmain (1969). These initial parameters are used as a starting point to drive a finite difference computational model of an antenna immersed in a plasma called PF-FDTD. The …

Constraining The Surface Inhomogeneity And Settling Times Of Metals On Accreting White Dwarfs, Michael H. Montgomery, S.E. Thompson, Ted Von Hippel

Publications

Due to the short settling times of metals in DA white dwarf atmospheres, any white dwarfs with photospheric metals must be actively accreting. It is therefore natural to expect that the metals may not be deposited uniformly on the surface of the star. We present calculations showing how the temperature variations associated with white dwarf pulsations lead to an observable diagnostic of the surface metal distribution, and we show what constraints current data sets are able to provide. We also investigate the effect that time-variable accretion has on the metal abundances of different species, and we show how this can …

A Novel Proof Of The Heine-Borel Theorem, Matthew Macauley, Brian Rabern, Landon Rabern

Publications

Every beginning real analysis student learns the classic Heine-Borel theorem, that the interval [0,1] is compact. In this article, we present a proof of this result that doesn't involve the standard techniques such as constructing a sequence and appealing to the completeness of the reals. We put a metric on the space of infinite binary sequences and prove that compactness of this space follows from a simple combinatorial lemma. The Heine-Borel theorem is an immediate corollary.

Gis Modeling And Mitigation Of Coral Reef Damage, Richard Snow, Mary Snow

Publications

The objective of this study is to demonstrate that an efficient instrument for conducting surveys and inventories of coral reefs to assess those ecosystems at higher risk and develop mitigation strategies is through the use of a Geographic Information System (GIS). Efficient monitoring requires the assessment of various coastal data baselines and the evaluation of subsequent alterations in spatial patterns. While monitoring involves real-time components, among the most powerful tools of a GIS are its modeling capabilities, which allow simulation of various climate change scenarios. Relevant aspects include changes in coastal land use, wetlands, and shoreline configuration. Using Caribbean coral …

Developing A Coherent Cyberinfrastructure From Local Campus To National Facilities: Challenges And Strategies, Amy Apon, Patrick Dreher, Vijay Agarwala, Stan Ahalt, Guy Almes, Sue Fratkin, Thomas Hauser, Jan Odegard, Jim Pepin, Craig Stewart

Publications

A fundamental goal of cyberinfrastructure (CI) is the integration of computing hardware, software, and network technology, along with data, information management, and human resources to advance scholarship and research. Such integration creates opportunities for researchers, educators, and learners to share ideas, expertise, tools, and facilities in new and powerful ways that cannot be realized if each of these components is applied independently. Bridging the gap between the reality of CI today and its potential in the immediate future is critical to building a balanced CI ecosystem that can support future scholarship and research. This report summarizes the observations and recommendations …

Excitation Of Ducted Gravity Waves In The Lower Thermosphere By Tropospheric Sources, Jonathan B. Snively, Victor P. Pasko

Publications

Short-period, small-scale gravity waves are frequently observed in nighttime airglow imaging experiments. These waves are often found to be ducted and may be confined to a thin region of altitude in the mesosphere or lower thermosphere. An apparent paradox of high-altitude ducted waves is the nature of the source; it is necessary that a ducted wave be excited in situ or have been able to tunnel into the duct from another atmospheric region. In this paper, analytical and numerical solutions are presented for simple thermally ducted gravity waves that are Doppler-shifted by constant background winds. Using a continuous analytical model, …

Guidance For Private Property Owners: Steps And Alternatives For Disposal Of Material Dredged From River And Harbors Of Casco Bay, Normandeau Associates, The Environment Company

Publications

The overall goal of the project is to help private owners navigate the dredging/disposal process and make informed decisions that are:

• Cost effective (including all steps of the process);
• In compliance with regulations; and
• Geared to specific needs (material volume, sediment type and level of contamination).

As part of this objective, we have attempted to do the following:

1. Describe the regulatory process for disposal alternatives (upland, ocean, and others) in simple but accurate terms.
2. Develop a complete list of disposal alternatives.
3. Develop a comprehensive alternatives analysis for possible disposal alternatives and screening process.
4. Develop a resource compendium in an appendix, …

Book Review: Guide To Observing Deep-Sky Objects: A Complete Global Resource For Astronomers, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Guide to Observing Deep-Sky Objects : a Complete Global Resource for Astronomers by Jeff A. Farinacci. Springer, 2007 189p, 9780387728506 $29.95

The First Mid-Infrared Spectra Of Cool White Dwarfs, Mukremin Kilic, Ted Von Hippel, Et Al.

Publications

We present the first mid-infrared spectra of two cool white dwarfs obtained with the Spitzer Space Telescope. We also present 3.5–8 μ m photometry for 19 cool white dwarfs with 5000 K ≤T_eff ≤ 9000 K. We perform a detailed model atmosphere analysis of these white dwarfs by fitting their UBVRIJHK and Spitzer photometry with state-of-the-art model atmospheres, and demonstrate that the optical and infrared spectral energy distributions of cool white dwarfs are well reproduced by our grid of models. Our mid-infrared photometry and 7.5-14.5 μm spectrum of WD 0018–267 are consistent with a T_eff = 5720 …

Dynamically And Statistically Downscaled Seasonal Temperature And Precipitation Hindcast Ensembles For The Southeastern Usa, Justin T. Schoof, D. W. Shin, S. Cocke, T. E. Larow, Y-K. Lim, J. J. O'Brien

Publications

We present results from a 15-year 10-member warm season (March–September) hindcast ensemble of maximum and minimum surface air temperatures and precipitation in southeast USA. The hindcasts are derived from the Florida State University/Center for Ocean-Atmospheric Prediction Studies Global Spectral Model (FSU/COAPS GSM) and downscaled using both the FSU/COAPS Nested Regional Spectral Model (NRSM) and a statistical downscaling method based on stochastic weather generator techniques. We additionally consider statistical bias correction of the dynamical model output. Basic descriptive statistics indicate that the bias-corrected and statistically downscaled data reduce the FSU/COAPS GSM bias considerably in terms of basic climatology. Statistics describing the …

Hypoelastic Modeling Of Reinforced Concrete Walls, Mohsen A. Shayanfar, Amir Safiey

Publications

This paper presents a new hypoelasticity model which was implemented in a nonlinear finite element formulation to analyze reinforced concrete (RC) structures. The model includes a new hypoelasticity constitutive relationship utilizing the rotation of material axis through successive iterations. The model can account for high nonlinearity of the stress-strain behavior of the concrete in the pre-peak regime, the softening behavior of the concrete in the post-peak regime and the irrecoverable volume dilatation at high levels of compressive load. This research introduces the modified version of the common application orthotropic stress-strain relation developed by Darwin and Pecknold. It is endeavored not …

An Application Of High Fidelity Ftds For Ab Initio Pilot Training: The Way Ahead, Nickolas D. Macchiarella, Tim Brady, Brandon S. Lyon

Publications

"Decreases in simulation costs and increases in aircraft training costs led to the need for further investigation into the application of simulation-based training. Researchers conducted an eighteen-month study using ab initio student pilots as participants. This study applied a Federal Aviation Administration (FAA) approved, Part 142, flight-training curriculum that included 60% flight training device (FTD) use. Researchers identified five causal factors that warranted further investigation. The causal factors identified were visual fidelity, procedural similarity, dynamic flight environment, difficulty of task, and visual scanning and response. These causal factors have the potential to affect transfer of training (ToT) from simulated flight …

Gis Forest Inventory And Evaluation In The Wake Of Climate Change, Mary Snow, Richard K. Snow

Publications

"Because climate and vegetation are so strongly associated, it is assumed that the forecast rapid changes in climate will affect plant distributions and alter the makeup of forest communities. For example, climate change could cause regional wind patterns to shift, which would be accompanied by an increase in wind speed intensity. Such shifts could impact existing rain shadow effects in some regions causing more precipitation on the windward side of mountain ranges while creating even drier conditions on the leeward sides. Fire patterns are likely to be altered as well, which could affect a variety of plant species, even those …

Fiber Bundle Description Of Flow And Nonlinear Hydrodynamics On Circles, Andrei Ludu

Publications

We introduce a differential geometry description of the path lines, stream lines and particles contours in hydrodynamics. We present a generalized form of a Korteweg-de Vries type of equation for the exterior of a circle. Nonlinearities from the boundary conditions, surface tension and the Euler equations are taken into account, but the flow is considered inviscid and irrotational. For the circular case we describe the traveling waves shapes, solitons and the particles trajectories.

Capacity Planning Of A Commodity Cluster In An Academic Environment: A Case Study, Linh B. Ngo, Amy W. Apon, Baochuan Lu, Hung Bui, Nathan Hamm, Larry Dowdy, Doug Hoffman, Denny Brewer

Publications

In this paper, the design of a simulation model for evaluating two alternative supercomputer configurations in an academic environment is presented. The workload is analyzed and modeled, and its effect on the relative performance of both systems is studied. The Integrated Capacity Planning Environment (ICPE) toolkit, developed for commodity cluster capacity planning, is successfully applied to the target environment. The ICPE is a tool for workload modeling, simulation modeling, and what-if analysis. A new characterization strategy is applied to the workload to more accurately model commodity cluster work- loads. Through "what-if" analysis, the sensitivity of the baseline system performance to …

Understanding And Predicting Ecological Dynamics: Are Major Surprises Inevitable?, Daniel F Doak, James A Estes, Benjamin S Halpern, Ute Jacob, David R Lindberg, James Lovvorn, Daniel H Monson, M Timothy Tinker, Terrie M Williams, J Timothy Wootton, Ian Carroll, Mark Emmerson, Fiorenza Micheli, Mark Novak

Publications

Ecological surprises, substantial and unanticipated changes in the abundance of one or more species that result from previously unsuspected processes, are a common outcome of both experiments and observations in community and population ecology. Here, we give examples of such surprises along with the results of a survey of well-established field ecologists, most of whom have encountered one or more surprises over the course of their careers. Truly surprising results are common enough to require their consideration in any reasonable effort to characterize nature and manage natural resources. We classify surprises as dynamic-, pattern-, or intervention-based, and we speculate on …

Markov Chain Monte Carlo Estimation Of Normal Ogive Irt Models In Matlab, Yanyan Sheng

Publications

Modeling the interaction between persons and items at the item level for binary response data, item response theory (IRT) models have been found useful in a wide variety of applications in various fields. This paper provides the requisite information and description of software that implements the Gibbs sampling procedures for the one-, two- and three-parameter normal ogive models. The software developed is written in the MATLAB package IRTuno. The package is flexible enough to allow a user the choice to simulate binary response data, set the number of total or burn-in iterations, specify starting values or prior distributions for model …

Book Review: The Road To Galaxy Formation 2nd Ed, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of The road to galaxy formation 2nd ed by William C. Keel. Springer/Praxis, 2007 262p, 9783540725343 $99.00.

A New Look At The Local White Dwarf Population, J. B. Holberg, E. M. Sion, Terry D. Oswalt, G. P. Mccook, S. Foran, John P. Subasavage

Publications

We have conducted a detailed new survey of the local population of white dwarfs lying within 20 pc of the Sun. A new revised catalog of local white dwarfs containing 122 entries (126 individual degenerate stars) is presented. This list contains 27 white dwarfs not included in a previous list from 2002, as well as new and recently published trigonometric parallaxes. In several cases new members of the local white dwarf population have come to light through accurate photometric distance estimates. In addition, a suspected new double degenerate system (WD 0423+120) has been identified. The 20 pc sample is currently …

The Robotic Super-Lotis Telescope: Results & Future Plans, G. G. Williams, P. A. Milne, H. S. Park, S. D. Barthelmy, Dieter H. Hartmann, A. Updike, K. Hurley

Publications

We provide an overview of the robotic Super-LOTIS (Livermore Optical Transient Imaging System) telescope and present results from gamma-ray burst (GRB) afterglow observations using Super-LOTIS and other Steward Observatory telescopes. The 0.6-m Super-LOTIS telescope is a fully robotic system dedicated to the measurement of prompt and early time optical emission from GRBs. The system began routine operations from its Steward Observatory site atop Kitt Peak in April 2000 and currently operates every clear night. The telescope is instrumented with an optical CCD camera and a four position filter wheel. It is capable of observing Swift Burst Alert Telescope (BAT) error …

Relativistic Particle-In-Cell Simulation Of Prompt And Early Afterglows From Grbs, K.-I. Nishikawa, P. Hardee, Y. Mizuno, M. Medvedev, B. Zhang, Dieter H. Hartmann, G. J. Fishman

Publications

Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., gamma-ray bursts (GRBs), active galactic nuclei (AGNs), and microquasars commonly exibit power-law emission spectra. Recent PIC simulations of relativistic electro-ion (or electron-positron) jets injected into a stationary medium show that particle acceleration occurs within the downstream jet. In collisionless, relativistic shocks, particle (electron, positron, and ion) acceleration is due to plasma waves and their associated instabilities (e.g., the Weibel (filamentation) instability) created in shock region. The simulations show that the Weibel instability in responsible for generating and amplifying highly non-uniform, small-scale magnetic fields. These fields contribute to the …

Implications Of Cosmological Gamma-Ray Absorption. Ii. Modifications Of Gamma-Ray Spectra, Dieter H. Hartmann, T. M. Kneiske, T. Bretz, K. Mannheim

Publications

Bearing on the model for the time-dependent metagalactic radiation field developed in the first paper of this series, we compute the gamma-ray attenuation due to pair production in photon-photon scattering. Emphasis is on the effects of varying the star formation rate and the fraction of UV radiation assumed to escape from the star forming regions, the latter being important mainly for high-redshift sources. Conversely, we investigate how the metagalactic radiation field can be measured from the gamma-ray pair creation cutoff as a function of redshift, the Fazio-Stecker relation. For three observed TeV-blazars (Mkn501, Mkn421, H1426+428) we study the effects of …

Equivalences On Acyclic Orientations, Matthew Macauley, Henning S. Mortveit

Publications

The cyclic and dihedral groups can be made to act on the set Acyc(Y ) of acyclic orientations of an undirected graph Y , and this gives rise to the equivalence relations ∼κ and ∼δ, respectively. These two actions and their corresponding equivalence classes are closely related to combinatorial problems arising in the context of Coxeter groups, sequential dynamical systems, the chip-firing game, and representations of quivers.

In this paper we construct the graphs C(Y ) and D(Y ) with vertex sets Acyc(Y ) and whose connected components encode the equivalence classes. The number of connected components …

Exist's Gamma-Ray Burst Sensitivity, D. L. Band, J. E. Grindlay, A. Garson Iii, H. Krawczynski, Dieter H. Hartmann, S. Barthemy, N. Gehrels, G. Skinner

Publications

We use semianalytic techniques to evaluate the burst sensitivity of designs for the EXIST hard X-ray survey mis-sion. Applying these techniques to the mission design proposed for the Beyond Einstein program,we find that with its very large field of view and faint gamma-ray burst detection threshold, EXIST will detect and localize approximately two bursts per day, a large fraction of which may be at high redshift. We estimate that EXIST’s maximum sensitivity will be ~4 times greater than that of Swift’s Burst Alert Telescope. Bursts will be localized to better than 40" at thresh-old, with a burst position as good …

Over-Ocean Validation Of The Global Convective Diagnostic, David W. Martin, Richard A. Kohrs, Frederick R. Mosher, Carlo Maria Medaglia, Claudia Adamo

Publications

The global convective diagnostic (GCD) is a bispectral (infrared and water vapor), day–night scheme for operationally mapping deep convection by means of geostationary satellite images. This article describes a test of GCD performance over tropical and subtropical waters near North America. The test consists of six cases, each involving a convective cloud complex. A seventh case treats convection over land. For each case, a map of deep convection was constructed from image pairs from Geostationary Operational Environmental Satellite-12 (GOES-12). Case by case and for all maritime cases together, the GCD map was compared with a convective parameter derived …

Volume I, Master Plan And Environmental Impact Report: Technical Map 2008 Update, Facilities Planning And Capital Projects, California Polytechnic State University - San Luis Obispo

Publications

No abstract provided.

A Magnetohydrodynamic Boost For Relativistic Jets, Yosuke Mizuno, Phillip Hardee, Dieter H. Hartmann, Ken-Ichi Nishikawa, Bing Zhang

Publications

We performed relativistic magnetohydrodynamic simulations of the hydrodynamic boosting mechanism for relativistic jets explored by Aloy & Rezzolla (2006) using the RAISHIN code. Simulation results show that the presence of a magnetic field changes the properties of the shock interface between the tenuous, overpressured jet (Vzj) flowing tangentially to a dense external medium. Magnetic fields can lead to more efficient acceleration of the jet, in comparison to the pure-hydrodynamic case. A "polodial" magnetic field (Bz), tangent to the interface and parallel to the jet flow, produces both a stronger outward moving shock and a stronger inward moving rarefaction wave. This …

Cognitive Processes Of Students Participating In Engineering-Focused Design Instruction, Todd R. Kelley

Publications

Since the publication of the Standards for Technological Literacy in 2000 (ITEA), there have been a number of new programs developed that are designed to teach pre-engineering. Project Lead the Way is one such program. Project Lead the Way boasts serving over 1250 schools in 44 states and teaching over 160,000 students (McVearry, 2003). Efforts are also being made to infuse engineering design into technology education programs. One example of this is the work of the National Center for Engineering and Technology Education (NCETE) partnering with high school technology educators in summer inservice workshops to help teachers develop activities and …

Nonlinear Control Strategy For Advanced Vehicle Thermal Management Systmes, John Wagner, M H. Salah, T H. Mitchell, D M. Dawson

Publications

Advanced thermal management systems for internal combustion engines can improve coolant temperature regulation and servomotor power consumption by better regulating the combustion process with multiple computer controlled electromechanical components. The traditional thermostat valve, coolant pump, and clutch-driven radiator fan are upgraded with servomotor actuators. When the system components function harmoniously, desired thermal conditions can be accomplished in a power efficient manner. In this paper, a comprehensive nonlinear control architecture is proposed for transient temperature tracking. An experimental system has been fabricated and assembled which features a variable position smart valve, variable speed electric water pump, variable speed electric radiator fan, …

Engineering Student Outcomes For Grades 9 - 12, Vincent W. Childress, Craig Rhodes

Publications

The article focuses on a study by Dearing and Daughtry about postsecondary engineering education. The study used a modified Delphi technique that they conducted with technology teachers, technology teacher educators, and engineering educators to identify engineering outcomes for high school pre-engineering students. The purpose of the study was to identify those concepts that are necessary to teach high school students in order to prepare them for postsecondary engineering education, while preserving the mission of teaching technological literacy.