Hoffman I.M.,Wittenberg University
Astrophysical Journal | Year: 2012
We present the first astronomical detection of the 14NH 3 (J, K) = (10, 6) line: nonthermal emission at several velocities in the Galactic star-forming region NGC7538. Using the Very Large Array we have imaged the (10,6) and (9,6) ammonia masers at several positions within NGC7538 IRS 1. The individual sources have angular sizes ≲ 0.1 arcsec corresponding to brightness temperatures TB ≳ 106 K. We apply the pumping model of Brown & Cragg, confirming the conjecture that multiple ortho-ammonia masers can occur with the same value of K. The positions and velocities of the (10,6) and (9,6) masers are modeled as motion in a possible disk or torus and are discussed in the context of recent models of the region. © 2012. The American Astronomical Society. All rights reserved.
Williams J.D.,Wittenberg University
Physics of Plasmas | Year: 2012
In this study, tomographic particle image velocimetry (tomo-PIV) techniques are used to make volumetric measurements of the dust acoustic wave (DAW) in a weakly coupled dusty plasma system in an argon, dc glow discharge plasma. These tomo-PIV measurements provide the first instantaneous volumetric measurement of a naturally occurring propagating DAW. These measurements reveal over the measured volume that the measured wave mode propagates in all three spatial dimensional and exhibits the same spatial growth rate and wavelength in each spatial direction. © 2012 American Institute of Physics.
Williams J.D.,Wittenberg University
Physics of Plasmas | Year: 2011
Over the past twelve years, two-dimensional and stereoscopic particle image velocimetry (PIV) techniques have been used to obtain detailed measurements of the thermal and transport properties of the microparticle component of dusty plasma systems. This letter reports on an extension of these techniques to obtain a volumetric, three-dimensional velocity vector measurement using tomographic PIV. Initial measurements using the tomographic PIV diagnostic are presented. © 2011 American Institute of Physics.
Agency: NSF | Branch: Continuing grant | Program: | Phase: NUCLEAR STRUCTURE & REACTIONS | Award Amount: 120.00K | Year: 2015
The research supported by this award will probe the limits of our understanding of the weak interaction, one of the four fundamental forces of nature. Among other things, the weak interaction is responsible for the type of radioactive decay called beta decay in which a nucleus is transformed into a different nucleus with the emission of an electron and a neutrino. The award will allow the two scientists to carry out experiments in which they precisely measure the energy of electrons emitted in four different nuclear beta decays. Three of these experiments will test key aspects of the Standard Model of the electroweak interaction, which is the theory that describes the unification of two of the fundamental forces, the weak interaction and the electromagnetic interaction. These precision beta decay measurements are complementary to particle collider experiments in the search for new physics. A fourth proposed experiment aims to resolve uncertainties in the beta decay of potassium-40, an important tool in geochronology. The research program has the further goal and benefit of training highly talented undergraduate physics students. Students involved will gain experience with state-of-the-art software and experimental techniques, and will learn to think independently and gain a variety of practical problem solving skills. The broader impact is felt when these students enter the workforce in STEM fields or in teaching.
The research program consists of several experiments involving the high precision measurement of the shapes of beta spectra. In two of the proposed experiments the goal is to provide a strong test of the Conserved Vector Current hypothesis in the electroweak sector of the Standard Model of particle physics. In a third experiment, the goal is to improve limits on non-Standard-Model contributions (Fierz terms) to the description of the weak interaction. A fourth experiment has the goal of resolving an uncertainty in the potassium-40 beta spectrum, which is relevant to applications in geochronology. Specifically, the carbon-14 beta spectrum will be measured using a new magnetic spectrometer at the University of Wisconsin-Madison. This spectrometer will be nearly identical in form to the superconducting spectrometer used to make the same measurement in oxygen-14, enabling reduced uncertainties arising from higher order matrix element contributions. Measurements in fluorine-20 and helium-6 will be carried out at the National Superconducting Cyclotron Laboratory using implantation into a scintillator detector, which will have significantly different systematic effects from the magnetic spectrometer measurements and will be important in achieving low thresholds. A fourth experiment has the goal of measuring the shape of the potassium-40 beta spectrum. Knowledge of this spectrum shape is important for a standard technique in radioactive dating of geologic samples, but a recent report suggests the shape may not be as well understood as had been thought. An important aspect of all these measurements is in assessing and correcting for systematic effects through measurement and computational modeling.
Agency: NSF | Branch: Standard Grant | Program: | Phase: | Award Amount: 43.07K | Year: 2013
This planning activity supports Wittenberg Universitys efforts in developing a plan to improve campus network infrastructure aligning with the goals and guidance described in NSF CISE/ACIs CC-NIE program. The 6-month planning period includes the following activities: assessing network infrastructure needs driven by science and education activities on campus; defining partnerships and collaborations on campus and elsewhere to create leveraging opportunities and help define those opportunities; and develop a complete plan documenting design, re-architecting, and implementation of an improved campus network that includes the science DMZ concept. Wittenberg University will also host a campus CI day. The activity creates the opportunity to make the most of existing infrastructure, both locally and regionally, and in turn enhance research capabilities internally and with partners outside the institution.
Agency: NSF | Branch: Standard Grant | Program: | Phase: PLASMA PHYSICS | Award Amount: 5.00K | Year: 2015
This award supports graduate student travel to the 14th Workshop on the Physics of Dusty Plasmas to be held at Auburn University, Auburn, Alabama in May 2015. The field of dusty plasmas constitutes a fully developed interdisciplinary field with direct connections to astrophysics, nanoscience, fluid mechanics and colloidal physics through experimental, theoretical and computational studies. This workshop will bring together researchers from around to the world to (1) provide a review of recent advances in the field of dusty plasmas, (2) help to define new and existing research questions and challenges and (3) help to strengthen the interaction between dusty plasma researchers and facilitate interactions between the field of dusty plasmas and other related research disciplines. The involvement of graduate students will contribute to the formation of the next generation of scientists working in this area.
Agency: NSF | Branch: Standard Grant | Program: | Phase: ROBERT NOYCE SCHOLARSHIP PGM | Award Amount: 1.17M | Year: 2011
Wittenberg University is providing scholarships to 16 junior and senior math and science majors who commit to completing four years of teaching at the secondary level in high need school districts, including Springfield City Schools, Mad River Local Schools, and Tecumseh Local Schools. The project specifically addresses the challenge of attracting and retaining highly qualified STEM teachers to high need schools through financial incentives, new licensure programs in chemistry and physics, early field experiences, and a mentoring program initiated during students sophomore year and continuing through their first year of teaching. The project provides early field experiences for college freshmen through internships in informal settings and schools serving high need students to spark an interest in teaching and internships for sophomores in research labs at the Pacific Northwest National Laboratory to prepare them to integrate research into their classroom teaching. A new STEM Teacher Learning Community is bringing together in-service teacher mentors, pre-service teachers, and Wittenberg STEM and STEM education faculty to nurture the professional development and growth of new teachers. The project builds upon established partnerships with high need schools, a new urban teaching track and fifth year induction program, and several established STEM programs including recently awarded state and NSF grants to increase the number of STEM graduates. The blend of strong content preparation and research experiences is preparing students to create environments of discovery and inquiry-based learning in their classrooms. The project addresses the challenge of attracting and retaining highly qualified STEM teachers, including in the difficult-to-recruit fields of physics and chemistry, to high need schools. The programs intentional design integrating research with educational experiences enables new STEM teachers to adopt similar models in their own classrooms, infusing education with the excitement of discovery and sparking their students interest in STEM. The new mentoring program and STEM Teacher Learning Community is establishing a mechanism for participation by Wittenberg STEM faculty in teacher preparation programs and for ongoing collaboration between Wittenberg STEM and STEM education faculty and area STEM teachers. By strengthening partnerships with high need districts, the project seeks to ensure a future pipeline of qualified STEM teachers to serve in area high need schools.
Agency: NSF | Branch: Standard Grant | Program: | Phase: | Award Amount: 75.00K | Year: 2015
The weak interaction, one of the four fundamental forces of nature, is responsible for the type of radioactive decay called beta decay. Precise measurements of beta decay can probe the limits of our understanding of the weak interaction, complementing particle collider experiments in the search for new physics while being much less costly. The recent development of facilities, such as at the National Superconducting Cyclotron Laboratory, that can produce a variety of beams of radioactive isotopes has created new opportunities for improved beta decay measurements. To fully exploit the potential of these new isotopes requires a good understanding of the response of various types of particle detectors. Understanding the response of particle detectors is also important for many applications in homeland security, nuclear safeguards, and medicine. The instrument to be acquired through this grant will enable the measurement of the response of a variety of particle detectors to a new level of precision over a wide energy range.
Precise measurements of the shapes of spectra in nuclear beta decay are sensitive to physics beyond the Standard Model of particle interactions. The recent development of powerful radioactive beam facilities has created a new opportunity for improved measurements of nuclear beta spectrum shapes through implantation of the nuclei in detectors that fully contain the emitted particles. In the ideal case, this provides measurements free of many of the systematic eﬀects more conventional beta spectroscopy is subject to. Fully exploiting the potential of the new detector method, however, requires precise knowledge of implantation detector response. This detector response characterization is the primary research to be enabled by the proposed acquisition of an all-digital multi-parameter gamma spectroscopy system. The basis of the characterizations is the Wide Angle Compton Coincidence technique. This technique uses Compton scattering with standard gamma sources of modest strength to characterize the energy dependent electron response of essentially any detector material relative to, for example, a High Purity Germanium detector. The system acquired under this proposal will enable the measurement of the nonlinearity of a wide variety of detectors to a new level of precision and over a wider energy range than presently exists.
Agency: NSF | Branch: Continuing grant | Program: | Phase: PLASMA PHYSICS | Award Amount: 100.00K | Year: 2016
The award will support a series of experiments aimed at understanding fundamental properties of a unique state of matter, a dusty or complex plasma, which is an ionized gas consisting of ions, electrons, and small particulate matter (dust or ice) that is typically much smaller than the width of a human hair. In space, examples of dusty plasmas include the clouds from which stars and planets form, comet tails, planetary rings and noctilucent clouds in the Earths ionosphere. Dusty plasmas are also formed in the chemically active plasmas that are used in industrial plasma processing devices to create computer chips, contaminating the end product and reducing overall yield, and the manufacturing of solar photovoltaic cells, where the dust can increase the overall efficiency of the resulting solar cells. The research program will support the training of several highly talented undergraduate students in a small college environment, providing the students with a more comprehensive research skills training than at comparable experiences at larger institutions; experience with state-of-the-art software and experimental techniques; and a variety of practical problem solving skills.
The research program consists of several experiments designed to understand the thermal and transport properties of weakly-coupled (fluid-like) dusty plasmas. One series of experiments is designed to measure the thermal state of weakly-coupled dusty plasmas to better understand the mechanism responsible for the high temperatures that have been measured in a number of experimental systems. This effort will directly test two models that are believed to be responsible for the observed heating and will also support the development of a time-resolved stereoscopic particle image velocimetry (PIV) system. This work will extend collaborative work done in the development of a time-resolved planar PIV with colleagues at in the Plasma Science Laboratory at Auburn University and the Complex Plasmas Research Group at the German Aerospace Center. Additionally, a portion of this work will be done at the newly operational Magnetized Dusty Plasma Experiment facility at Auburn University and will examine the effect that magnetic fields have on the thermal state of these dusty plasma systems. A second series of experiments is designed to understand the properties of a fundamental wave mode that propagates in dusty plasma systems known as the dust acoustic wave. The contribution that thermal effects have on how this wave propagates and the nonlinear process of synchronization where the properties of the wave adjust to match an externally applied drive will be investigated. Together, these studies will contribute to the fundamental understanding of the thermal properties of dusty plasmas and provide new insight into the nonlinear properties of the dust acoustic wave.
Williams J.D.,Wittenberg University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2014
The spatiotemporal evolution of the naturally occurring dust acoustic wave mode is experimentally investigated in a weakly coupled dc glow discharge dusty plasma system over a range of neutral gas pressures through the application of a time-resolved Hilbert Transform. Frequency clusters are observed over a range of neutral gas pressures, though their spatial distribution varies with neutral gas pressure. It is also observed that the wave frequency is observed to drop by ∼10 Hz across these frequency clusters independent of the experimental parameters. © 2014 American Physical Society.