The innermost Galilean satellite, Io, is the most volcanically active body in the solar system. The volcanic activity leads to material being released into Jupiter's magnetosphere near Io's orbit. This material becomes ionized and trapped in Jupiter's rotating magnetic field. The trapped material forms a torus of material around Jupiter that is called the Io plasma torus. It contains an inner cold torus and an outer warm torus. In this dissertation, I determine and interpret the distribution of plasma in the Io plasma torus from radio occultation observations by the Juno spacecraft. I perform a feasibility study to show that Juno radio occultation observations should be able to detect the Io plasma torus. Based on this feasibility study, I predict that key Io plasma torus parameters -- value and location of maximum total electron content, and scale height -- can be determined with 10--20 percent uncertainties. I analyze Juno radio occultation observations from Perijove 1. Perijove is the point where the spacecraft makes its closest approach. The observations are taken for a 6 hour period around perijove and are labeled as Perijove followed by a number which corresponds to the orbit number. From the observations I determine the Io plasma torus parameters and find that inferred densities are ~30% larger than models suggested. These results show that Juno radio occultation observations can detect and usefully characterize the Io plasma torus. I analyze data from Perijoves 3, 6, and 8 and determine how Io plasma torus parameters vary. In this set of observations, the warm torus maximum total electron content and scale height do not vary greatly. I test the prediction that the torus lies in the centrifugal equator by modeling the equator location. Observed and predicted locations agree reasonably if a Juno magnetic field model and a simple current sheet model are used. I find that the contribution of the current sheet is significant, which suggests that remote observations of the location of the Io plasma torus can be used to constrain Jupiter's magnetospheric current sheet.

The Computational Fluid Dynamics General Notation System provides a unified way in which computational fluid dynamics data can be stored, but does not support the parallel I/O capabilities now available from version five of the Hierarchical Data Format library which serves as a back end for he standard. To resolve this deficiency, a new parallel extension library has been written and benchmarked for this work which can write files compliant with the standard using parallel file access modes. When using this new library, the write performance shows an increase of four-fold in some cases when compared to the same hardware operating in serial. Additionally, the use of parallel I/O allows much larger cases to be written since the problem is scattered across many nodes of a cluster, whose aggregate memory is much greater than that found on a single machine. These developments will allow computational fluid dynamics simulations to execute faster, since less time will be spent waiting for each time step to finish writing, as well prevent the need for lengthy reconstruction of data after the completion of a simulation.

The development of protype applications with sensors and actuators in the automation industry requires tools that are independent of manufacturer, and are flexible enough to be modified or extended for any specific requirements. Currently, developing prototypes with industrial sensors and actuators is not straightforward. First of all, the exchange of information depends on the industrial protocol that these devices have. Second, a specific configuration and installation is done based on the hardware that is used, such as automation controllers or industrial gateways. This means that the development for a specific industrial protocol, highly depends on the hardware and the software that vendors provide. In this work we propose a rapid-prototyping framework based on Arduino to solve this problem. For this project we have focused to work with the IO-Link protocol. The framework consists of an Arduino shield that acts as the physical layer, and a software that implements the IO-Link Master protocol. The main advantage of such framework is that an application with industrial devices can be rapid-prototyped with ease as its vendor independent, open-source and can be ported easily to other Arduino compatible boards. In comparison, a typical approach requires proprietary hardware, is not easy to port to another system and is closed-source.

Cassini spacecraft images of Io obtained during its flyby of Jupiter in late 2000 and early 2001 were used to determine the lava composition and eruption style of three faint hotspots, Pillan, Wayland, and Loki. We found a maximum color temperature of 1130+/-289 K for Pillan and maximum color temperatures of 1297+/-289 K and 1387+/-287 K for Wayland and Loki, respectively. These temperatures are suggestive of basaltic lava. The temperatures with the best signal-to-noise ratios also suggested basaltic lava and were found to be 780+/-189 K, 1116+/-250 K, and 1017+/-177 K for Pillan, Wayland, and Loki, respectively. Pillan showed increased activity on the third eclipse day after being fairly constant for the first two days, suggesting increased fountaining or lava flow activity on the third day. The data also suggest that Pillan is surrounded by topography that blocked emission on day000 and caused a much more dramatic decrease in emission. Wayland's intensity decreased over the three eclipses, consistent with a cooling lava flow or decreasing eruption. However, rapid decreases in intensity over periods of 26 to 48 minutes could have resulted from the eruption of highly exposed lava, perhaps an open channel or fountain. The data also suggest Wayland may be in a depression surrounded by ridges that blocked part of the emission. Intensities at Loki over the course of the observation varied in both directions, and were consistent with previous determinations of an often quiescent lava lake with periods of active overturning and fountains.

Paterae cover approximately 2% of the surface of Io, Jupiter’s volcanically active moon. To understand the formation of these volcano-tectonic depressions we created a geologic map of a key region and compared this map with experimental models for Io paterae. Our mapping region is Tupan Patera, a patera that has experienced recent activity and is a detected hot spot. We identified four primary types of geologic materials: plains, patera floors, flows, and diffuse deposits. We constructed an experimental model to test previous suggestions that paterae may form as volatiles in the silicate crust are vaporized by rising magma, creating instability, and subsequent collapse. The apparatus is a scaled model that uses sand (silicate crust analog), ice or snow (volatile analog), a hotplate (magma chamber analog), and a moveable paddle (to simulate extension). Our experimental collapse features exhibit many characteristics of paterae on Io, such as “islands,” terraces, straight margins, and steep scarps. Our model suggests that the role of volatiles in Io’s crust is a significant part of paterae formation.Comparative studies between our map and model show it is possible Tupan is an emerging lava lake or one in a state of quiescence. Our studies have also culminated in the completion of a theoretical cross section for the geologic history of Tupan Patera. This cross section displays a sequence of events including the rise of magma as it preferentially volatilizes sulfurous layers in the crust, subsequent thinning, instability, and collapse, the likelihood of the patera floor sinking as a stoped block, and the more recent flow and diffuse deposits. This study gives some insight to the general formation of paterae on Io.

Performance of the I/O subsystem plays a significant role in parallel applications that need to access large amounts of data. I/O performance in such applications is expected to be scalable and balanced with respect to the communication and CPU performance. MPIIO, a part of the MPI-2 standard has many implementations. Each of the available clientside parallel architectures differ widely in their approach to achieving high performance. This thesis hypothesizes that the effectiveness of each available client-side parallel architecture differs in delivering overall parallel application performance for a given underlying file system and that increasing the performance for different workload characteristics requires different designs. This hypothesis is validated by the development of appropriate metrics and the analysis of the results, obtained from running the experiments.

ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / The Joint Mission Environment Test Capability (JMETC) is a distributed live, virtual, and constructive (LVC) testing capability developed to support the acquisition community and to demonstrate Net-Ready Key Performance Parameters (KPP) requirements in a customer-specific Joint Mission Environment (JME). JMETC provides connectivity to the Services’ distributed test capabilities and simulations, as well as industry test resources. JMETC uses the Test and Training Enabling Architecture, TENA, which is well-designed for supporting JMETC events. TENA provides the architecture and software capabilities necessary to enable interoperability among range instrumentation systems, facilities, and simulations. TENA, used in major field exercises and numerous distributed test events, provides JMETC with a technology already being deployed in DoD.

The following study attempted to operationalize the willingness to work hard component of Hogan’s RAW model of employability. Willingness to Work Hard, the W in the model, appears to be multi-faceted; a qualitative synthesis of themes suggests that the construct may be dispositional. I examined proactive personality by using the G ProACT scale to help understand the multi-dimensionality of Willingness to Work Hard. Taking initiative, rigidness, planning, and anticipating opportunities were the four subscales that emerged. The purpose of my study was to collect evidence of construct validity for the proposed measure. I examined the relationship between the G ProACT measure and discriminant and convergent variables. A survey was distributed among CSUSB students that contained the G ProACT measure, demographic related items, and other established measures to gather construct validity. A confirmatory factor analysis (CFA) with 488 participants indicated a lack of support for the hypothesized model. Specifically, the CFA revealed that three of the four factors did not relate to the presumed construct of proactive personality. Rigidness showed no relationship whereas anticipating opportunities and planning demonstrated marginal relationships to the underlying construct. Follow-up analyses indicated that taking initiative was the only subscale deemed as strongly factorable. Findings suggest a need to further explore taking initiative to determine if the measure appropriately captures the dispositional nature of Willingness to Work Hard. Future research should continue to examine if proactive personality or other motivational constructs are an appropriate fit for the RAW model.

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Io has one of the most dynamic atmospheres in the solar system due in part to an orbital resonance with Europa and Ganymede that causes intense tidal heating and volcanism. The volcanism serves to create a myriad of volcanic plumes across Io's surface that sustain temporally varying local atmospheres. The plumes primarily eject sulfur dioxide (SO₂) that condenses on Io's surface during the relatively cold night. During the day, insolation warms the surface to temperatures where a global partially collisional atmosphere can be sustained by sublimation from SO₂ surface frosts. Both the volcanic and sublimation atmospheres serve as the source for the Jovian plasma torus which flows past Io at ~57 km/s. The high energy ions and electrons in the Jovian plasma torus interact with Io's atmosphere causing atmospheric heating, chemical reactions, as well as altering the circumplanetary winds. Energetic ions which impact the surface can sputter material and create a partially collisional atmosphere. Simulations suggest that energetic ions from the Jovian plasma cannot penetrate to the surface when the atmospheric column density is greater than 10¹⁵ cm⁻². These three mechanisms for atmospheric support (volcanic, sublimation, and sputtering) all play a role in supporting Io's atmosphere but their relative contributions remain unclear. In the present work, the Direct Simulation Monte Carlo (DSMC) method is used to simulate the interaction of Io's atmosphere with the Jovian plasma torus and the results are compared to observations. These comparisons help constrain the relative contributions of atmospheric support as well as highlight the most important physics in Io's atmosphere. These rarefied gas dynamics simulations improve upon earlier models by using a three-dimensional domain encompassing the entire planet computed in parallel. The effects of plasma heating, planetary rotation, inhomogeneous surface frost, molecular residence time of SO₂ on the exposed non-frost surface, and surface temperature distribution are investigated. Circumplanetary flow is predicted to develop from the warm dayside toward the cooler nightside. Io's rotation leads to a highly asymmetric frost surface temperature distribution (due to the frost's high thermal inertia) which results in circumplanetary flow that is not axi-symmetric about the subsolar point. The non-equilibrium thermal structure of the atmosphere, specifically vibrational and rotational temperatures, is also examined. Plasma heating is found to significantly inflate the atmosphere on both the dayside and nightside. The plasma energy flux causes high temperatures at high altitudes, but plasma energy depletion through the dense gas column above the warmest frost permits gas temperatures cooler than the surface at low altitudes. A frost map (Douté et al., 2001) is used to control the sublimated flux of SO₂ which can result in inhomogeneous column densities that vary by nearly a factor of four for the same surface temperature. A short residence time for SO₂ molecules on the non-frost component is found to smooth lateral atmospheric inhomogeneities caused by variations in the surface frost distribution, creating an atmosphere that looks nearly identical to one with uniform frost coverage. A longer residence time is found to agree better with mid-infrared observations (Spencer et al., 2005) and reproduce the observed anti-Jovian/sub-Jovian column density asymmetry. The computed peak dayside column density for Io agrees with those suggested by Lyman-[alpha] observations (Feaga et al., 2009) assuming a surface frost temperature of 115 K. On the other hand, the peak dayside column density at 120 K is a factor of five larger and is higher than the upper range of observations (Jessup et al., 2004; Spencer et al., 2005). The results of the original DSMC simulations of Io's atmosphere show that the most important and sensitive parameter is the SO₂ surface frost temperature. To improve upon the original surface temperature model, we constrain Io's surface thermal distribution by a parametric study of its thermophysical properties. Io's surface thermal distribution is represented by three thermal units: sulfur dioxide (SO₂) frosts/ices, non-frosts (probably sulfur allotropes and/or pyroclastic dusts), and hot spots. The hot spots included in the thermal model are static high temperature surfaces with areas and temperatures based on Keck infrared observations. Elsewhere, over frosts and non-frosts, the thermal model solves the one-dimensional heat conduction equation in depth into Io's surface and includes the effects of eclipse by Jupiter, radiation from Jupiter, and latent heat of sublimation and condensation. The best fit parameters for the SO₂ frost and non-frost units are found by using a least-squares method and fitting to observations of the Hubble Space Telescope's Space Telescope Imaging Spectrograph (HST STIS) mid- to near-UV reflectance spectra and Galileo photo-polarimeter (PPR) brightness temperature. The thermophysical parameters are the frost Bond albedo, and thermal inertia, as well as the non-frost surface Bond albedo, and thermal inertia. The best fit parameters are found to be [equations] for the SO2 frost surface and [equations] for the non-frost surface. These surface thermophysical parameters are then used as boundary conditions in global atmospheric simulations of Io's sublimation-driven atmosphere using DSMC. The DSMC simulations show that the sub-Jovian hemisphere is significantly affected by the daily solar eclipse. The SO₂ surface frost temperature is found to drop ~5 K during eclipse but the column density falls by a factor of 20 compared to the pre-eclipse column due to the exponential dependence of the SO₂ vapor pressure on the SO₂ surface frost temperature. Supersonic winds exist prior to eclipse but become subsonic during eclipse because the collapse of the atmosphere significantly decreases the day-to-night pressure gradient that drives the winds. Prior to eclipse, the supersonic winds condense on and near the cold nightside and form a highly non-equilibrium oblique shock near the dawn terminator. In eclipse, no shock exists since the gas is subsonic and the shock only reestablishes itself an hour or more after egress from eclipse. Furthermore, the excess gas that condenses on the non-frost surface during eclipse leads to an enhancement of the atmosphere near dawn. The dawn atmospheric enhancement drives winds that oppose those that are driven away from the peak pressure region above the warmest area of the SO₂ frost surface. These opposing winds meet and are collisional enough to form stagnation point flow. The simulations are compared to Lyman-[alpha] observations in an attempt to explain the asymmetry between the dayside atmospheres of the anti-Jovian and sub-Jovian hemispheres. A composite "average dayside atmosphere" is formed from a collisionless simulation of Io's atmosphere throughout an entire orbit. The composite "average dayside" atmosphere without the effect of global winds indicates that the sub-Jovian hemisphere should have lower average column densities than the anti-Jovian hemisphere (with the strongest effect at the sub-Jovian point) due entirely to the diurnally averaged effect of eclipse. Lastly, a particle description of the plasma is coupled with the sophisticated surface thermal model and a final set of global DSMC atmospheric simulations are performed. The particle description of energetic ions from the Jovian plasma torus allows for momentum transfer from the ions to the neutral atmosphere. Also, the energetic ions (or solar photons) can dissociate the neutral atmosphere and cause sputtering of SO₂ on the surface. SO₂ remains the dominant dayside species (>90%) despite being dissociated by ions and photons to form O, O₂, S, and SO. SO₂ remains the dominant atmospheric species on the nightside between dusk and midnight due to sputtering of SO₂ surface frosts by energetic ions as well as the high thermal inertia of SO₂ frosts that cause the surface temperature to cool slowly and thus sublime a thicker SO₂ atmosphere. O₂ becomes the dominant atmospheric species above coldest areas of the surface because it is non-condensable at Io's surface temperatures and other species are sticking to the surface. SO and O are present in similar gas fractions because they are created together via the same ion and photo-dissociation reactions. Sulfur column densities are the lowest throughout the atmosphere because S is created slowly via direct dissociation of SO₂; it is instead created primarily through dissociation of SO. The momentum transfer from the plasma is found to have substantial effect on the global wind patterns. The interaction between the plasma pressure and day-to-night pressure gradient is highly dependent on Io's subsolar longitude. Similar to previous simulations, the westward winds reach higher Mach numbers and wind speeds than the eastward winds. This is because the westward winds are accelerated by a larger day-to-night pressure gradient due to the very cold surface temperatures that exist prior to dawn. Eastward equatorial winds on the nightside are accelerated by the plasma pressure and condense out near the dawn terminator after traveling ~3/4 of the circumference of Io. O₂ is pushed to the nightside by the circumplanetary winds where it builds-up until it reaches an equilibrium column density. On the nightside, O₂ is destroyed by ion dissociation. On the nightside, a shear layer develops between the equatorial eastward winds and stagnant non-condensable species at mid-latitudes. This shear layer generates lateral vorticity which is especially visible in O₂ streamlines. Large cyclones develop in the northern and southern hemispheres and are most apparent in the O₂ wind patterns because other species condense out on the nightside. / text