Physics Lecture Series | Spring 2015

I was first introduced to geophysics during a Seismic Exploration class my junior year at University of Oklahoma. I was intrigued with how one could use physical properties, which can be directly measured, to understand the subsurface. In the summer of 2010, I was able to add to this classroom experience through a summer internship with the United States Geological Survey seismic hazard team. During the summer we collected data to image sediments near the New Madrid seismic zone. This data would ultimately allow the team to better understand the possible impacts of future earthquakes in that region.

Why study geophysics? Because there are numerous career opportunities for geophysicists! Facets of geophysics are for everyone... from the environmental and geotechnical engineering to academic research and the energy industry career opportunities abound. Geophysics is a dynamic, young science that is very cutting edge; I would say more cutting edge than other science in terms of how the average scientist gets their hand on top notch software and data. If you are inclined to math, physics, computer science, then there is a place for you in geophysics.

Recent advances in Astrophysics! Learn about disks around stars (called accretion disks), ultra-strong magnetic fields, nebulae, and how a team armed with supercomputers, laboratory experiments and telescopes gets deep into the mysteries of how stars eject energy into space.

I will show results of very powerful simulations of accretion disks forming in systems of 2 stars orbiting each other (binaries). The simulations are 3D and high resolution (calculation-wise) thus we can see details of the disks' structure and hydrodynamics. As we play with the separation of the model stars, we find what would happen in different scenarios/systems. The results have important scientific implications, for example I will discuss how we can claim that only specific types of binaries will form nebulae; a conclusion that is hidden from telescopes.

Then, I will talk about how accretion disks with ultra-strong magnetic fields are able to eject energy into space. You will see the case of pure magnetic energy transformed into supersonic streams of really hot magnetized gas. Again, powerful simulations let us explore these "magnetic towers" with such a detail that we can understand how they evolve in time, what destroys them and how they look from Earth. I will show how magnetic towers are also formed in laboratory experiments, adding a new component in the toolbox of Astrophysics. This is very exciting as we demonstrate a quantitative connection between the physics of real millimeter-long gasses, virtual 100K AU-long (hundreds of times larger than the distance between Earth and the Sun) nebulae, and telescope observations.

Supersymmetry (SUSY) is one of the best motivated extensions to the Standard Model of particle physics. In particular SUSY provides a natural solution to the hierarchy problem and a natural dark matter candidate. The basic ideas of SUSY will be presented. The prospects for discovering supersymmetric particles at the Large Hadron Collider (LHC) and in dark matter direct-detection experiments will also be discussed.

Our understanding of the formation and evolution of galaxies has come a long way in the last century since Hubble's original "Tuning Fork". As with most areas of science, the ultimate goal is to develop a standard model of galaxy evolution that incorporates all of the observational and physical attributes of galaxies as they change over time. I will discuss some of the main features of galaxies and describe how their properties and populations have evolved. I will also present an overview of a comprehensive computational model of this evolution and discuss how recent observations have informed its parameters and confirmed some of its predictions.

Recent and current NASA and JAXA spacecraft missions have and are returning asteroid and comet samples at mission costs upwards of 300 millions dollars each. It is more cost effective (almost free) to more efficiently collect these materials they encounter Earth. This can be done using ground-based weather radars, which are deployed worldwide. I will describe recent successes in using radar to locate freshly fallen meteorites on the ground, and relate our plans for linking up a world-wide network to expand these efforts.

In this presentation a review galactic cosmic ray (GCR) effects on microelectronic systems and human health and safety is given. The methods used to evaluate and mitigate unwanted cosmic ray effects in ground-based, atmospheric flight, and space flight environments are also reviewed. However not all GCR effects are undesirable. We will also briefly review how observation and analysis of GCR interactions with planetary atmospheres and surfaces and reveal important compositional and geophysical data on earth and elsewhere.

About 1000 GCR particles enter every square meter of Earth's upper atmosphere every second, roughly the same number striking every square meter of the International Space Station (ISS) and every other low-Earth orbit spacecraft. GCR particles are high energy ionized atomic nuclei (90% protons, 9% alpha particles, 1% heavier nuclei) traveling very close to the speed of light. The GCR particle flux is even higher in interplanetary space because the geomagnetic field provides some limited magnetic shielding. Collisions of GCR particles with atomic nuclei in planetary atmospheres and/or regolith as well as spacecraft materials produce nuclear reactions and energetic/highly penetrating secondary particle showers.

Three twentieth century technology developments have driven an ongoing evolution of basic cosmic ray science into a set of practical engineering tools needed to design, test, and verify the safety and reliability of modern complex technological systems and assess effects on human health and safety effects. The key technology developments are: 1) high altitude commercial and military aircraft; 2) manned and unmanned spacecraft; and 3) increasingly complex and sensitive solid state micro-electronics systems. Space and geophysical exploration needs drove the development of the instruments and analytical tools needed to recover compositional and structural data from GCR induced nuclear reactions and secondary particle showers. Finally, the possible role of GCR secondary particle showers in addressing an important homeland security problem, finding nuclear contraband and weapons, will be briefly reviewed.

The images connected with earning a degree in physics are often associated with pictures of brilliant shabby dressed or lab-coated scientists toiling away in obscurity behind four concrete walls, a small office space or conducting lectures in University classrooms. Rarely are there images of physicists working on Wall Street, negotiating global treaties, or advising the President of the United States and yet these are where you will find many physical scientists. Christophe McCray, a reformed laser physicist will tell his story of how his physics career took him from academia, to industry, to Government and finally to the nonprofit sector where he currently serves as a Senior Research Staff Member (RSM) at the Institute for Defense Analyses, a research and policy institute serving the Department of Defense and US Government. He hopes through his story, students will see that a physics degree does not restrict your options but expands them.

With elevating pressure in the global competition for complex product requirements and shorter developmental schedules, engineers are pushed to generate more design under less time, without sacrificing accuracy. Accurate results help to prevent over-engineering along with its embedded costs. With high-fidelity CFD results in hand, engineers can design within smaller safety factors, which can reduce total product developmental cost and ultimately reduce the time to market.

This seminar introduces ANSYS CFD (Computational Fluid Dynamics) solutions and its application to Simulation Driven Product Development (SDPD) through industrial examples and success stories from a variety of different industries. It is intended to provide a high level overview of CFD and its effective deployment in a typical designer's workflow. Typical applications of CFD are engineering problems involving fluid flows and heat transfer combined with phenomena such as turbulence, chemical reactions, particulates, multiple fluid phases with or without phase change, as well as fluid-structure interactions (FSI). Thermal analyses such as electronics cooling applications will also be discussed.

Beyond the direct application of a physics degree in a physics or technical career, we'll discuss opportunities that exist in career fields you may not have considered, but may have an interest...such as national policy.

Designing hardware to operate in the space radiation environment is a very difficult and costly activity. Ground based particle accelerators can be used to test for exposure to the radiation environment, one species at a time, however, the actual space environment cannot be duplicated because of the range of energies and isotropic nature of space radiation. The FLUKA Monte Carlo code is an integrated physics package based at CERN that has been under development for the last 40+ years and includes the most up-to-date fundamental physics theory and particle physics data. This work presents an overview of FLUKA and how it has been used in conjunction with ground based radiation testing for NASA and improve our understanding of secondary particle environments resulting from the interaction of space radiation with matter.

Would you purchase a brand new automobile that had little documentation on how it was designed, built, and tested? What if you learned that very little testing was done to the vehicle? Why does the display or the transmission computer keep going out on you? For spaceflight, there are no second chances for success and no prelaunch flight test. For deep space missions, the hardware must work right the first time for the duration of the mission despite environmental threats and potential failures. If you ever wondered why the documentation and processes for certifying a system for spaceflight can be challenging, this presentation help answer the question. A high level overview of the flight certification process for spaceflight hardware will be given that includes the NASA project life cycle and systems engineering process. In addition, design, development, and test necessary to prove the hardware is ready for spaceflight will also be discussed. Physics majors might find the discussion of systems engineering interesting. Their training in math, problem-solving, and reasoning skills are a good match for a career in systems engineering.

Nanomaterials like carbon nanotubes, dendrimers, and nanoparticles have become part of our everyday life due to a multitude of possible applications in electronics, engineering, medicine and healthcare.

After a short introduction into the development of theoretical and experimental nanoscience and an overview of different kind of nanostructures and their properties, we will take a closer look at metal nanoparticles. Our research focuses on the synthesis and analysis of gold nanoparticles (Au Np) with various sizes and ligand shells. Different synthesis and analysis methods as well as photothermal experiments with a laser system will be discussed.

The photothermal effect in Au Np is caused by surface plasmon resonance. It is of great interest because the generated heat can be used in biomedical applications such as imaging, drug delivery and therapy. One important application is the effectiveness of Au Np in destroying cancerous cells. In order to gain a better understanding of how Au nanoparticles cause cell death, they have been crosslinked to a fluorescent protein to specifically target cultured cancer cells. First results on cell death caused by laser treatment of this nanoparticle cell system are also presented.