The Physics Department has been successful in attracting external funding from the Office of Naval Research, the Naval Surface Warfare Center, the Naval Research Laboratory, the National Science Foundation, the Applied Physics Laboratory of the University of Washington and corporate sponsors. The department received internal support from the Naval Academy Research Council and the Curriculum Development Committee.
This work is of immeasurable importance in maintaining the exciting intellectual atmosphere which carries into the classroom and becomes apparent to our students. The student involvement in this effort is designed to give the midshipmen a real lesson in the rigors and excitement of probing new areas of science. The results are apparent because they have resulted in invited presentations and well-received talks. It is particularly gratifying to see a paper appear which demonstrates the collaboration of officers who contributed several years ago when they were midshipmen along with our current class of midshipmen. In all, thirty presentations were given by the faculty and midshipmen.
The Physics Department's research program is vital, wide-ranging, and has continuity. This bodes well for continued excellence.
Chalcogenide glasses are transparent in the mid-infrared region (3-12µm), making them a suitable material for mid-IR devices. In particular optical wave-guides made from chalcogenide glass can be used to deliver and detect mid-IR radiation and thus are being developed for a variety of applications including chemical sensors, IR countermeasures, laser surgery, and machining
We will refurbish a F-center laser to be used as an IR source for measuring transmission through chalcogenide glass and fibers. In addition, we will build an apparatus which will be used to side-write gratings in both single mode fibers and planar wave-guides
This work is still in progress. We have demonstrated that holographic structures can be recorded in both bulk glasses and multimode fibers, but we have not been able to successfully "read" them using the tunable F-center laser.
A total of twenty one two-hour classes in calculus were distributed throughout the summer. This course was essentially a review of the basic calculus with an emphasis on its development and an introduction to vector calculus.
A review of electromagnetic theory was presented which proceeded through a detailed treatment of the radiating dipole. This is all done in preparation for a subsequent theoretical description of the infrared data which Mr Sarman will be obtaining with the Bi-Directional Reflectometer at Carderock.
An informal report of this work was submitted at the end of the summer to Mr. Peter Sarman of the Naval Surface Warfare Center in Carderock , MD.
The goal of this project is to build a computer-based tutoring system, named Andes, that will help students learn classical physics. The development team includes physicists, cognitive scientists, computer scientists, and programmers.
My activities on the project this year have included selecting or developing instructive problems in kinematics, Newtonian dynamics, and work-energy methods, authoring detailed tutorial solutions for several of them, developing production rules for solving work-energy problems, and consulting on the design of an interface for tutoring conceptual problem-solving skills and workbench tools for work-energy problems. In addition, I participated in student-testing an early version of the workbench for solving Newtonian dynamics problems.
The current studies involve the extension of the Propagator Solution to point and line driven panels with application to several acoustics problems of interest to the Navy and the numerical evaluation of certain significant measurable parameters. Of the parameters evaluated, the "partial radiation efficiency" has proved most interesting in that it predicts that damping does not always reduce radiated power. In fact, it has been shown that the radiated power may well be significantly enhanced at certain frequencies when damping is arbitrarily applied.
This study involves the 1st and 2nd level development of the Propagator Solution to several standard idealized acoustics problems in Physics. In the 1st level, some simple physics problems normally solved via eigenvalue methods were completed to validate the technique unambiguously. These problems have very well known and accepted solutions which the Propagator method will reaffirm. Actually, this first level should be completed during the summer intersessional period under Code 804.1 funding. At the 2nd level of this project, several very idealized eigenvalue resonance problems (examples: 1D, a perfectly uniform string; 1D, a uniform string with periodic bead masses; 2D, multiple simply connected quadrilateral structures; etc.) were solved using the Propagator method which are then very matter-of-factly be extended to include deviations from symmetry. The well known perturbation methods of extending the standard eigenvalue solutions are, in contrast, long, difficult, and, in many cases, fail to reliably converge.
The purpose of this project is to develop a method for materials analysis using heavy ions instead of alpha particles. Since the scattering cross section increases as the square of the projectile charge, using heavy ions can greatly enhance the sensitivity of the method. By using a magnetic spectrometer for mass resolution and a position-sensitive detector (PSD) for efficiency, we hope to push the technique to sensitivity sufficient to detect iron impurities on silicon substrates at the level of a few tens of billions of iron atoms per square centimeter.
During the summer of 1996, the magnetic spectrometer was resurrected, and the position-sensitive detector was installed and de-bugged. A few spectra were taken at the end of the summer. The spectra indicate that an effect known as "scalloping" or "pebbling" may be due to the magnetic spectrometer itself, and not due to the PSD as had been thought. Scalloping is an effect that causes a quasiperiodic structure in spectra that are reasonably expected to be flat. Work during the summer of 1997 will focus on resolution of the scalloping problem.
The sun's chromosphere is a layer approximately 5000 km thick just outside the photoshpere, the surface of the sun we see from Earth. Outside the chromosphere is the corona, which extends several million kilometers into space. Many questions about these outer regions of the sun remain unanswered, such as the mechanisms by which the corona is heated to its temperature of 1.6 million degrees, and the changing temperature and elemental composition of the chromosphere. Since the sun is a rather common G2-type star, information about the chromosphere and corona is of interest to stellar astrophysicists as well as to solar physicists. Because the photosphere is brighter than the chromosphere and corona by five to seven orders of magnitude, these active and dynamic parts of the sun can be observed only if the photoshpere is blocked out. Coronagraphs obscure the photosphere with a small disk placed inside a telescope, but these instruments suffer from diffraction around the edges of the disk, and from scattering by molecules and dust particles in the atmosphere. Also, it is difficult to completely occult the photosphere but leave the chromosphere unobscured with a coronagraph because the chromosphere is so thin. For these reasons, the most effective land based studies of the chromosphere and of the corona are executed during total solar eclipses, when the moon occults the sun. Since the moon is large and distant, diffraction effects are negligible, and since it resides outside the atmosphere, scattering effects are absent.
A total solar eclipse will be visible from the small island of Aruba in the Netherlands Antilles on 26 February 1998. In return for help in planning an expedition to observe the eclipse, Innovations in Travel, Inc., has agreed to provide air travel and hotel accommodations for the principal investigator, one midshipman and two technicians from the U.S. Naval Academy, and for one faculty member and one cadet from the U.S. Coast Guard Academy. After consultation and negotiation with the Judge Advocate General, the Associate Dean for Faculty Affairs has granted permission to accept this support.
The experiments that will be done in Aruba are under development, but include plans to study the spectrum of the chromosphere, timings of certain special events during the eclipse, polarization of the corona, and shadow bands.
The goals of the project are to study the structure and electrical properties of electrode materials and ion-exchange membranes. Electrical conductivity studies will be carried out over a wide range of temperatures and pressures on lithium, cobalt and vanadium oxide materials. In addition, nuclear quadrupole resonance techniques will be developed for use on these materials. For ion-exchange membranes, work will be carried out primarily on acid doped polybenzimidazole (PBI). The materials will be studied over a wide range of frequencies, temperatures and pressures. The structure and electrical conductivity of electrode materials are of fundamental interest. Structural studies are important because this class of materials is known to exhibit different phases in different temperature and (presumably) pressure regimes. Ultimately, it is the structure, in conjunction with the nature of the atoms, which determines whether or not a material can function as an electrode material. Since it is necessary that an electrode be a good conductor, the electrical conductivity is also important. In the case of the PBI and other ion-exchange membranes, the variable temperature and pressure experiments will provide insight both into the transport mechanism and into the nature of the diffusing species.
The investigation of resonant sound from a spherical cloud of air bubbles in water is made practical for experimentation by using bubbly castor oil enclosed in a thin elastic shell which is submerged in water. The resonant transmission theory involves placing a small spherical transducer element at the center of the bubbly spherical cloud. If the particle velocity u(r=a,t) = Uo ejt is known at the surface of the transducer of radius a, then the boundary conditions (imposing continuity of the acoustic pressure and the radial component of acoustic particle velocity) can be used to find the pressure inside and outside the cloud. The sound speed, density and wave number in a bubbly medium are formulated using the expressions developed by Commander and Prosperetti [J. Acoust. Soc. Am., Vol. 85, No. 2, 1989]. At sufficiently low frequencies the sound speed can be predicted from the volume void fraction (when is small but not too close to zero). The theoretical pressure amplitude radiating outside the cloud, |p|, is plotted vs from 0 to 10,000 radians/s (corresponding to a frequency range of 0 to 15.9 kHz) using a program that was developed on Mathematica. The radius b of the bubbly cloud is b= 5.08 cm and a = 0.508 cm.
Resonance curves are computed for bubbly water and bubbly castor oil for volume void fractions of = 0.01, 0.001 and 0.0001. The average bubble radius is taken to be 5x10-3 cm which corresponds to bubble radii measured when casor oil is whipped up in a micro blender in our laboratory. For = 0.001 the first few resonant peaks in the transmission spectrum occur at roughly 1,000 ; 3,000; 5,000 rad/s for bubbly water (there are more than 10 noticeable peaks) and the Q of the first peak is about 12. However, for bubbly castor oil there are only two noticeable peaks (at 1,000 and 3,000 rad/s) and the Q of the first peak is about one. This study compliments the more difficult procedure (both experimentally and theoretically) of determining the resonant frequencies from the backscattering of sound from an incident plane wave off of a bubbly sphere. Transmission experiments are scheduled in the USNA Hydrodynamics Tow Tank Facility during the summer of 1997.
This work entails the updating and development of computer interfaces used by the midshipmen in the physics laboratory. Hardware and software evolution requires the continuous development of the workstations to meet current and future data acquisition requirements. The software presently used was developed in a version of National Instrument's LabVIEW programming language that is no longer supported by the company. The goals of this project include translation of the software presently used into the new version of LabVIEW as well as the implementation of new tools that can help clarify physical principles in a laboratory experiment.
I am working with a team of programmers and graphics artists on a prototype of HyperText Physics Tutor (HyPT) to be released on compact disk. This educational tool will teach physics problem solving integrating QuickTime movies of simulations and video out-takes with more traditional instructional media.
Upconversion is a process which results in the emission of light from a material that is being optically pumped by light lower in frequency than the emission. This is achieved by converting two or more low frequency input photons into a single high frequency output photon. As a result, it is possible to produce blue emission from a crystal that is being pumped by an infrared diode laser. The upconverting crystal can be coupled with the diode pump laser into a compact package to produce a visible light laser. Such systems have immediate applications in the optical data storage industry. Lasers of this nature have been constructed, but are not yet commercially viable due to limitations in performance of known upconverting materials. It is the purpose of this ongoing project to identify new upconverting materials, determine the particulars of the upconversion process itself, and identify the conditions necessary to optimize the process sufficiently to produce laser emission.
Precise (0.5 per cent) data was collected using a carefully demagnetized cylindrical sample of Navy hull steel. Magnetization and susceptibility levels were measured for various sequences of magnetic field from the demagnetized state. Additional data was taken on the magnetization induced for various stress states applied to the sample with and without magnetic field. A theory of hysteresis was envisoned but not yet confirmed or published. Computational magnetoelastic theory has not yet been implemented to compare with the data.
Classical physics is a prerequisite for virtually all university level studies of science and technology yet is a notoriously difficult subject for students to learn. We are building a tutoring system , named ANDES, that will help students learn physics. ANDES is based on the latest research in Cognitive Science as well as input from a team of physics instructors with years of experience in instructional reform. When completed, ANDES will be used at the U. S. Naval Academy to enhance the introductory physics course, SP211, which is taken by approximately 1000 students per year.
The coding and cognitive science portions of the system is being done by Professor Kurt VanLehn's group at the Learning Research and Development Center at the University of Pittsburgh, the domain knowledge will furnished by Professors Correll, Wintersgill and Shelby of the USNA Physics Department, and knowlege base construction, coding, and coordination will be done by Professor Schulze of the USNA Computer Science Department.
The structure and electrical properties of ion-exchange membranes are currently being studied. Nuclear magnetic resonance (NMR) and electrical conductivity studies have been carried out over a range of pressures on NAFION thin-film samples hydrated with varying amounts of D2O or CH3OD. The goal is to systematically explore proton mobilities in these samples and correlate these motions with segmental motions of the NAFION polymer matrix. Deuteron NMR spin-lattice relaxation measurements of isotopically enriched methanol/water mixtures in NAFION 117 at elevated pressures demonstrate greater molecular-level interactions between methanol and NAFION than between water and NAFION. This is consistent with the plasticizing effect observed in the conductivity results.
All work undertaken was in support of ongoing efforts at the Naval Research Laboratory in Code 5640. Under this program, the current studies of optical detection and analysis of debris in turbine engine lubrication fluids, imaging through turbid media and correlator studies using multiple quantum well devices were extended. Elements included in the program were:
1. Modification of image analysis software
2. Lubricant optical transmission studies
3. Optical studies of small wear particles in lubricants
4. Real-time evaluation of debris in turbine engine lubricants
5. Quantum well photorefractive image correlators
6. Development of support electronics
The stable tellurium nuclei have two valence protons with respect to Z = 50 and a range of neutron numbers. Three different types of structure are thought to be active in these nuclei: collective, two-particle, and particle-hole excitations known as intruders. Because there are seven stable even-even Te nuclei, one can study the evolution of these excitation modes over a wide range in neutron number. Emphasis centers on understanding the interplay between particle and collective features and on the aspects of the nuclear forces that determine the relative importance.
The level schemes of the even-mass 124Te, 126Te, 128Te, and 130Te nuclei have been constructed by measuring gamma rays following excitation of a target nucleus by inelastic neutron scattering. Using a recently developed - coincidence technique, we were able to contruct the level scheme up to approximately 3300 keV. Angular distributions and Doppler shifts were measured to extract level spins, parities, and lifetimes and calculate transition rates between levels required for comparison to nuclear models. A standard Interacting Boson Model (IBM-2) treatment produced moderate agreement with measured level energies and transition rates. Two implementations of the more refined Particle-Vibrational Core Model (PCM) treatment were completely unable to adequately describe these nuclei. The simpler IBM-2 treatment produces more reliable explanations than these two "more advanced" PCM calculations. An explanation of the nuclear structure of the 6+ state in the tellurium nuclei remains elusive.
The student modeling module of an intelligent tutoring system (ITS) infers a student's line of reasoning given the student's user interface actions. It thereby determines what pieces of knowledge a student employed in taking those actions, and thus what pieces of knowledge are known by the student. The ITS makes important pedagogical decisions based on both the student's line of reasoning and the student's knowledge mastery.
The existing technology for student modeling needs improvement. Its first problem is combinatorial. Because the ITS assigns the problem the student is working on, student modeling is usually done by pre-computing the whole problem space for the problem, then searching it to find a solution path that matches the student's actions. In many task domains, the problem spaces are too large to use this technique, so the ITS designers artificially reduce their sizes by designating only some possible solution paths as "correct." In many task domains, it appears possible to vastly reduce the size of the pre-computed data structures by taking advantage of certain redundancies in the problem space.
The second problem is that inferring a line of reasoning from student actions is fraught with uncertainty. Students may know a rule, but fail to recall and use it. Sometimes students generate correct actions via lucky guesses. Often an action can be derived by both correct and incorrect lines of reasoning. Existing student modeling systems often use heuristics to cope with such uncertainties.
We will use sound, probabilistic reasoning instead. In particular, the system will use Bayesian belief networks. Because the reasoning is sound, the systems' assessments should be able to hold up to the same psychometric and legal standards that are applied to conventional multiple choice tests. We will develop a student modeling module based on these ideas, and demonstrate its combinatorial feasibility by using it in the context of simple ITS for university physics. We will evaluate the internal validity of the assessments using artificial students. We will evaluate the external validity using real students and verbal protocols.
Over the past decade, studies of the interstellar medium in our galaxy have highlighted the prevalence and importance of large scale structures in the distribution of gas in the disk and halo. Heiles (1984) presented a catalog of H I shells, shell-like loops and worms. Some of these structures are believed to be several kiloparsecs in size and show coherent structure in space and velocity. We obtained interstellar absorption spectra of Ca II H and K lines and Na I D1, D2 lines at high resolution ( about 7 km/s) toward 61 stars in the directions of interstellar H I shells. Intermediate velocity gas is observed toward a number of our program stars. Results from the optical observations are being compared to H I data on the shells to evaluate their distances, kinematics and abundances.
Optical coherence tomography is used to map out sub-surface structure in both organic and inorganic samples. In order to create the image, the sample is placed at the end of one arm of a Michelson interferometer. The reference arm has a mirror at the end and can be varied in length. Light from a braodband source is injected into one port of the interferometer; the other port is used to detect the output signal of the interferometer. As the length of the reference arm is varied, light reflected from the sub-structure in the sample will be correlated with the light from the reference arm. The correlated signal is detected at the output of the interferometer using a photodiode. The three dimensional image is reconstructed by combining the depth information at each point along the surface of the sample.
The goal of this research is to develop temporal image processing techniques.
These techniques will be used to enhance the contrast of 3 dimensional
images taken using an optical coherence microscope (OCM). Preliminary work
has shown that deconvolving the point transfer function from the temporal
scan data can lead to enhanced contrast. However, do to limited signal
to noise, the reconstructed signal is necessarily band-limited. Following
well known analytical techniques developed for spatial image processing,
we expect to extend bandwidth of the object spectrum which will lead to
further improvements in image contrast.
Investigation Of The Human Voice Mechanism
For more than a generation, there has been a search for the time profile of the defining pulse produced by oscillation of the glottal folds, made difficult because the primary sound is obscured by laryngeal cavity resonances. Previous attempts to isolate the seminal pulse have included time-frequency voice displays, highspeed optical devices, inverse filtering and reflectionless tubes. In the present investigation attention has been confined to the vocal fry range (gestures at rep rates less than 100 Hz.), using a Sondhi reflectionless tube with variable damping. In this way it is possible to study the signature of single glottal pulses. The conventional source of sound attributed to action of vocal folds is modulation of air volume flow through the glottis, generating monopole acoustic radiation. However, from examination of single glottal pulses uttered in the vocal fry range, using Sondhi tube and strobed video, an additional quadrupole source has been detected which stems from the fluctuating forces of the glottis on surrounding fluid. It is the quadrupole source, in fact, that seems to define the shape of observed pressure trace in the single glottic pulse. This pulse, which lasts 10 ms or less, resembles a single cycle of negative sine wave beginning at closing phase, followed by a weaker response at opening phase, as indicated by Electroglottograph (EGG) activity. Monopole sound which is emitted in short pulses during the abrupt closing and opening action of the glottis shows up as small superposed peaks along the quadrupole wave in a reflectionless tube. The quadrupole pressure trace, or q-wave, forms the acoustic signature of the single glottic pulse or SGP, and may be observed in ordinary sound emissions outside the tube, where glottic pulse wave trains with embedded monopole pulses and head echoes become tone samples. The new approach appears to have possible clinical applications and could be useful for studying such diverse phenomena as voice stress, singers ring, gender-specific factors, and pathological vocal folds.
There are several projects upon which are thought about or worked upon intermittently.
1. Modeling, from first principles, a representation of the Jovian magnetosphere during a semi-inflated state, as observed during the Voyager II flyby. The expanded version of the Voyager II Era magnetosphere field model was the one most applicable to correct predictions and useful data analysis for the July 1994 Shoemaker-Levy 9 Encounter with the Jovian magnetosphere, (which culminated in the collision with the planet). A manuscript co-authored with Ens. Todd Bode has been favorably received by the editor of Planetary and Space Science. Other works, generally in collaboration with European colleagues regarding the application of IME results to observations of the SL9 encounter with Jupiter have been presented or are in process. One paper is currently in press for a forthcoming special dedicated issue of Planetary and Space Science. A floppy magnetodsk to replace a rigid magnetodisk is currently being incorporated.
2. New investigations will be made on the Mercury magnetospheric field, in response to a published review on Mercury which contains some conclusions which are not supported by this investigator's experience. Also, I was contacted by an investigator interested in obtaining time dependent configuration modeling for analysis of some more recently observed photo-ionization of heavy ions (especially sodium) near the disc of Mercury. IME presented her work at the European Space Agency Workshop for planning a new mission to Mercury and her model has been formally requested and supplied for use in mission planning. The associated paper has been published in a special issue of Planetary and Space Science (January 1997). Midshipman Jacob Scott will undertake as a special project the mapping of the boundaries of the magnetospheric models being used by ESA investigators for mission planning
3. Adapting alternate sets of orthogonal functions for three-dimensional representation of magnetospheres for earth and other planets with intrinsic planetary magnetic fields.
4. Modeling, from first principles, as in #1, or by scaling from a function set, as in #3, self-consistent, three-dimensional global magnetospheres of Uranus and Neptune.
5. The relation of observed temporal variations of magnetospheric configurations to the proximate causes and consequential phenomena are being studied which will include investigations of the mechanisms for transport of particles, momenta, and energy related to the aforesaid phenomena. Attempts are being made to model upstream shock waves attributable to diurnal variations of Jovian magnetopause position.
6. IME has modeled, from first principles, a representation of the Saturnian magnetosphere as observed during the Pioneer 11 and Voyager I and II flybys. An expanded (from original version) paper written jointly with Sylvestre Maurice had been published in the Journal of Geophysical Research.. Midshipman Mark Skubis worked on an "upgrade" of the model by incorporating a non-equatorial plane incidence of the solar wind as his 1995-96 Trident Project. A follow-up paper has been published on details of possible size and shape configurations when a plausible range of directions of incident solar wind and solar wind pressure are considered with co-authors Trident Scholar Mark Skubis, as well as French nationals Sylvestre Maurice and Michel Blanc. The model has been adopted by the CASSINI mission investigators as their basic magnetic field model for planning purposes for the planned orbiting mission to Saturn. Several presentations based upon the work have been made in Europe. A current project "upgrade" is the affixing of a realistic model of a magnetotail to the global model.
Work progressed on several improvements to experiments used in the Physics of the Atom sequence of courses for physics majors.
Aristarchus' Experiment: Students are to determine the size and distance of the moon by making a simple observation during a lunar eclipse. Two lunar eclipses occurred in the past year. Although direct observation of the eclipse was not possible due to poor weather during both eclipses, we worked out a technique to make the required measurements using images of the eclipses from videotaped newscasts.
Self pumping in photorefractive crystals is easily observed for continuous wave laser beams and is well documented. During a previous period of NARC sponsored funding it was found that self pumped phase conjugation is easily observed in BSKNN when the input laser beam consists of pulses of about 120 picoseconds duration and 82 MHz rep rate from a modelocked argon ion laser. In fact, the response is very similar to that from a CW beam. However, self pumping with trains of 3 picosecond pulses with the same rep rate derived from the synchronously pumped dye laser produce only a very weak self pumped response from the crystal. It is the difference in behavior between the CW and pulsed cases that is the primary focus of this study. The main objective is to understand why the self pumping response in photorefractive crystals is different for CW laser beams and modelocked pulse trains. Possible benefits to gaining this insight are: 1) Since it occurs completely inside the crystal it is difficult to probe self pumping. Short pulses can provide a spatial or temporal probe so that better physical models can be developed and tested, 2) Self pumpin is rather a slow process that takes several seconds to thirty minutes to achieve.
The "tablecloth trick" has been used by physicists and magicians for many years. The audience is delighted as a tablecloth is pulled from beneath the pieces of an elegantly set table. This demonstration is often used to discuss inertia and friction with no attention given to torque. However, the frictional force acting on the stemware is applied tangentially, often resulting in the glassware tipping over rather than be dragged off the table. A careful analysis of this situation provides a wealth of information about the more subtle aspects of friction and torque. Objects may tip over while still sliding on the cloth, or as they decelerate they may tip on the tabletop after the cloth has departed. We have designed an apparatus that allows variation of parameters such as cloth speed, surface roughness, and moment of inertia of the tipping object. We have also developed equations to predict stability conditions for the system. Research has centered on testing the apparatus and evaluating the validity of our predictions. The apparatus and results will be presented at the August 1997 meeting of the American Association of Physics Teachers. It is the ultimate intention to use the apparatus in the upper level physics major laboratory for studying frictional forces and torque.
There is a continuing effort to upgrade low-field Nuclear Magnetic Resonance (NMR) at the Academy. This project is being developed by bringing the 0-21 kG electromagnet on line and by upgrading the existing pulsed and continuous wave (CW) NMR/NQR equipment.
The Varian electromagnet has been interfaced with a 1 ppm field stabilization unit (Walker Scientific rotating coil unit and console). This unit will operate in both field sweep and static mode. Currently, the magnet is cooled using continuously running tap water. A more efficient method of temperature maintenance is proposed by incorporation of a Neslab water chiller.
Non-adiabatic superfast-passage NMR experiments (NASP) are currently being planned. NMR equipment currently maintained such as the Mid-Continent continuous wave receiver/transmitter unit, Varian crossed-coil NMR probes, the Kepco power supply and the Nicolet signal averager will be employed to carry out NASP experiments.
A Ritec 1-45 MHz pulsed unit has been obtained and is currently being set up as a pulsed NMR/NQR spectrometer. This device has a distinct advantage over the currently owned Matec equipment in that it uses a dual channel quadrature detection scheme. This unit will measure NQR resonances and spin-lattice relaxation times for a variety of solid state systems. Research projects involving midshipmen will commence when the above systems are made operational. Such projects will involve fabrication of NMR probes and development of various lineshape simulation programs in analyzing solid state spectra.
The purpose of this study was to evaluate the acoustical differences between male and female speech to determine how listeners identify the gender of a given speaker while also determining the actual word (vowel) being spoken. In order to further understand these differences, the same words used in Peterson and Barney (1952) were recorded and analyzed using the CSL (Computerized Speech Laboratory) and ASL (Analysis-Synthesis Laboratory) programs. The actual analysis included only the center vowel of each of the ten words. The analysis that followed included determining the fundamental frequency (F0), and first and second formants (F1 and F2). To compare the differences between male and female speech, differences in absolute frequencies were noted as well as ratios of F2 to F1. Using only the methods described above, it is most likely that vowel recognition is accomplished by noting the ratio of F2 to F1, while gender is determined primarily by the absolute fundamental frequency of that vowel.
The goal of the project is to make measurements of materials under dry conditions and at high pressures. As the first step towards achieving this end, a glove box was instrumented and made operational. This included adding a pumping and circulation system, an exchange gas system, and installation and calibration of oxygen and water sensors. The completed glove box provided an environment with less than 0.15 ppm of water. Both sample loading and experiments can be carried out inside. The first application was to load samples of dry polybenzimidazole for measurement at high pressures. The samples were then transferred to a high pressure vessel and measurements of the effect of pressure on the electrical conductivity were carried out.
Using Very Large Array (VLA) observations at 332.9 and 1,375 Mhz, spectral indices of various features in 3C10 were analyzed with tomography techniques. A ring of emission with spectral index ~ -0.5 was found perpendicular to a NE-SW axis (position angle ~ 73). The ring is not present in the total intensity maps at either wavelength. The remainder of 3C10 was found to be relatively featureless, with a spectral index of -0.52 at the rim and steepening to -0.85 toward the center. In addition, a steep spectrum wind was discovered to the east of the source.
In an attempt to find whether the correlation between optical and radio luminosity of radio galaxies and the Fanaroff and Riley (FR) classification can be further broken down into subsets, we use Fanaroff & Riley's original definition of their classification scheme (Fanaroff & Riley, 1974) to re-measure 191 galaxies and divide the two FR classes in sub-groups using an FR scale. We find that no correlation exists between radio and optical luminosity and the associated FR classification using Fanaroff and Riley's original definition of the two classes of radio galaxies. We also find that no group of ratios is favored over any other. These results challenge Fanaroff and Riley's ordinal correlation as well as our basic understanding of the nature of radio galaxy morphology.
PC-IMAT (Interactive Multisensor Analysis Training) was developed in 1994 by NPRDC as a set of software tools to satisfy the initial need to enhance the training of aviation ASW operators. While Navy training opportunities have decreased (reductions in deployments, encounters and shore-based training facilities) training requirements have increased. The PC-IMAT project is proving to be a flexible and effectively evolving computer based training / educational platform needed to help tackle ASW and other tasks which require extensive analysis, classification and interpretational skills. Students taking SP411 (Underwater Acoustics and Sonar) are currently using PC-IMAT to help investigate what are the effective instructional strategies which convey understanding of a complex multivariate domain (like ray tracing or propagation loss models). Recent research on "scientific visualization" (to enhance comprehension and retention) and modeling from student feedback will be used to help develop and evaluate existing training materials. Questions arise naturally. What are the issues of the educational platforms to successful learning? What is the best computer utilization so that there is efficient evolution in the distributed training - whose contents have been reviewed, overhauled and accepted by experts in the field? Finally, ship-board training is limited by the senior person's knowledge. Solutions to these questions will be investigated with midshipman participation.
Measurements of sound transmission vs frequency are performed (in the Rickover Hall Hydrodynamics Tow Tank Facility) for a submerged spherical bubble cloud that is encapsulated by a thin spherical shell. The bubble cloud is driven by a miniature spherical PZT transducer unit that is suspended in the center. A theoretical model has been developed which predicts the resonant frequencies for the case where the shell thickness has negligible effect. Therefore, the resonances will depend on the radius of the cloud and the sound speed in the bubbly media (which is a function of the air volume void fraction). A shell of urethane elastomer is molded as a single piece by using the "lost wax technique." Hemispherical molds are used. The first set is for making the "inner" spherical wax ball. The second set forms the "outer" boundary of the casting for the spherical shell with filling ports on the north and south poles. The shell's inner wax material is then melted out to complete the process. The shell is nearly acoustically transparent since r =1.03 g/cm3, clong ~ 1450 m/s and ctran ~ 70 m/s. The bubbly fluid consists of castor oil that has been whipped in a microblender.
We describe the results of a mini-survey of interstellar Ti II and Ca II absorption towards 42 early-type stars observed from the southern hemisphere at a spectral resolution of 4.5 km/s. Results are also presented for the Na I ultraviolet line (3302 A) detected towards nine of these targets. We examine the dependence of the integrated column densities N(Ti II), N(Ca II), and N(Na I) on distance, reddening, neutral hydrogen column density, and their galactic elemental abundance. Our findings support the proposition that Ti II and Ca II absorption originate in the same regions of the pervasive, warm and neutral intercloud gas of the interstellar medium. We have observed a clear correlation of decreasing Ti and Ca abundance with increasing line-of-sight gas density. The Ti II/Ca II abundance ratio has been found to be essentially constant under all the interstellar density conditions we have sampled. Thus, we conclude that the general absorption properties of titanium (and calcium) are similar throughout the entire disk of our galaxy.
EDMONDSON, C. A, LCDR, USN, Coauthor, "High pressure NMR and electrical conductivity studies of gel electrolytes based on poly(acrylonitrile)" Solid State Ionics, 85, 173-179 (1996).
The effect of high pressure on electrical conductivity and NMR in gels prepared from lithium or sodium perchlorate, ethylene carbonate, dimethyl carbonate and poly(acrylonitrile) (PAN) has been determined. The corresponding liquids were also studied. Complex impedance studies at frequencies from 10 to 108 Hz and NMR measurements of T1 were carried out as a function of pressure up to 0.25 GPa. Activation volumes for NMR relaxation and ionic conductivity were calculated from the variable pressure data. Both activation volumes were found to be approximately the same in the liquids. For the gels, however, the NMR activation volumes are the same or lower than for the liquid while the electrical conductivity pressure dependencies are larger. The implications of these results are discussed in terms of possible effects of the PAN on the ionic solvation shell.
ELDER, Samuel A., Coauthor, Fluid Physics for Oceanographers and Physicists, 2nd ed., Butterworth/Heinemann, Oxford, UK, 1996.
This is the second edition of a text designed for teaching undergraduate fluid dynamics. The book has benefited greatly from the fact that an earlier version has now been used in the classroom for six years, giving the authors a chance to correct errors and improve the intelligibility of the text. Feedback from students has been helpful in deciding which topics to omit and which to expand more fully. New material includes instability of stratified flows and introduction to geostrophic flow. The text is less demanding, mathematically, than most other fluid mechanics texts on the market, though it covers essentially all the basic equations of incompressible flow. The most appreciative audience for Fluid Physics has proven to be among undergraduate students in oceanography, geology, biology and other environmental sciences, who tend to lack a rigorous background in math and physics. Furthermore, because it is short, the book is priced attractively.
ENGLE, Irene M., Coauthor, "The Geometry Of Saturn's Magnetopause,"Journal of Geophysical Research 101, 27053-27059 (1996).
We report upon a simple parameterization of the idealized three-dimensional model of Saturn's magnetopause, which is described in Maurice and Engle [1995]1. For a subsolar point at Rsub = 24 Rs, the parameterization is based on a series of ellipses which reproduce the shape of the magnetopause in planes parallel to the solar-ecliptic YZ plane. The 3D model is easily scaled for 17 Rs < R m < 40 Rs. This representation of Saturn's magnetopause is found to be consistent with the Voyager 1 magnetopause crossing observations. The same representation applied to Pioneer 1 and Voyager 2 confirms the variations of the subsolar point distance during these encounters. The model is intended for use in support of the Cassini mission planning.
S. Maurice and Irene M. Engle, "Idealized Saturn Magnetosphere Shape and Field", Journal of Geophysical Research 100, 17143-17151, (1995).
ENGLE, Irene M., "Mercury's Magnetosphere: Other Views," Planetary and Space Science 45, 127-132 (1997).
The measurements made of the Mercury magnetic field during the Mercury I flyby and the Mercury III flyby have been incorporated into models of the Hermean magnetosphere-magnetotail system. Because Mercury was coincidentally at the same position in its orbit for both flybys, both data sets have customarily been used together to fit the parameters of any particular model for characterizing the intrinsic Mercury planetary field. This paper presents results of simultaneously fitting the separate data sets with the assumption that the interior planetary magnetic field was the same during both the Mercury I and Mercury III flybys but that the solar wind pressure and/or direction of incidence could have been different during the times of the two flybys.
ENGLE, Irene M., Coauthor, "Magnetic Mapping Of Auroral Signatures Of Comet Sl9 In The Jovian Magnetosphere,"* Planetary and Space Science (final copy submitted April, 1997)
The electrodynamic interaction of Comet Shoemaker-Levy 9 (SL9) with the Jovian magnetosphere gave rise to the detection of several unique phenomena in the UV, X ray and radio wavelength ranges. Among them, the detection of an unusual FUV bright spot in Hubble Space Telescope images of the southern polar cap on July 20, just before P2 collision, may be attributed to auroral-like processes triggered by the charged environment of the comet fragments. We model here in detail the time-varying morphology of the instantaneous magnetic field lines passing through the comet fragments during their crossing of the magnetosphere, with special focus on the location of the magnetic footprint and the nature of the field line. We show that the FUV bright spot, not corotating with the planet, is likely to be related with a fragment still in the magnetosphere, and that fragment Q is the most presumable source of the interaction, as its footprint can easily be resolved from fragment P2's, and also, although less easily, from the more distant fragment R to W's ones. We show also that Q, as well as the other fragments, was on an open magnetic field line at the time of the observations, in agreement with the absence of observable conjugate emission in the north. But, the deformation of the magnetic field line passing through Q during the following few hours is such that it presumably became closed to the northern hemisphere during two separate periods between the observations under study and fragment Q's collision. A series of X ray bursts detected in the north precisely during the first of these periods could be related to the same process and strengthen our identification. A second UV set of data was taken during the same period of closed field lines, but due to an unfavourable viewing geometry, the identification of observed bright spots with fragment Q footprint is more ambiguous. Finally, we estimate crudely the energy of the particles precipitating in the FUV spot, and discuss briefly possible plasma processes.
Ertel, John P., Coauthor, General Physics Laboratory Manual, American Heritage Custom Publishing, Hamden, CT, (1996).
This most recent edition of the General Physics Laboratory Manual, 1997 - 1998 contains five principle parts.
I. The first part gives the student
1) a feeling for the purpose of doing physics laboratories -- why are laboratories integral to the understanding of physical phenomena;
2) a description of the elements of a physics laboratory report -- what we expect from them in laboratory write-ups;
3) a familiarization of graphing techniques and what should be included with any graph;
4) an introductory lesson in error propagation and uncertainty concepts.
II. Once the student understands in general what we are doing and why we are doing it all physics laboratories we move on to the second part of the book. With the addition of the Real Time Physics component in our laboratories, the nature of the laboratory experience was substantially changed (from previous years) and a new set of fall or 1st-term Mechanics and Waves Experiments in Real Time Physics had to be crafted. This section consists of seven new experiments as well as five more that are of our old style in the Lab View idiom.
III. The third part of the manual consists of nine Mechanics and Waves experiments for the fall or 1st-term with Lab View software. Some of these laboratories had to be extensively rewritten from our previous edition while others required only modest corrections and updates due to software and hardware improvements.
IV. Then comes the fourth part of the manual which consists of nine more experiments with Lab View software for the 2nd-term in Electricity, Magnetism, and Optics. Many of these experiments were extensively rewritten from our previous edition to cover updates due to software and hardware improvements while others required only modest corrections.
V. The fifth and last part is composed of "appendices" which give the student an understanding of the theory and practical use of some of the equipment and instruments used in a physics laboratory. This part is closed off with sets of problems for the entire academic year in Mechanics, Waves, Electricity, Magnetism, and Optics that are typical of those that the student will see on exams and quizzes in both style and degree of difficulty. Arguably, this is the most popular section of the entire book for our students!
FONTANELLA, John J., Coauthor, "High pressure NMR and electrical conductivity studies of gel electrolytes based on poly(acrylonitrile)" Solid State Ionics, 85, 173-179 (1996).
The effect of high pressure on electrical conductivity and NMR in gels prepared from lithium or sodium perchlorate, ethylene carbonate, dimethyl carbonate and poly(acrylonitrile) (PAN) has been determined. The corresponding liquids were also studied. Complex impedance studies at frequencies from 10 to 108 Hz and NMR measurements of T1 were carried out as a function of pressure up to 0.25 GPa. Activation volumes for NMR relaxation and ionic conductivity were calculated from the variable pressure data. Both activation volumes were found to be approximately the same in the liquids. For the gels, however, the NMR activation volumes are the same or lower than for the liquid while the electrical conductivity pressure dependencies are larger. The implications of these results are discussed in terms of possible effects of the PAN on the ionic solvation shell.
FONTANELLA, John. J., Professor, Coauthor, "High Pressure Electrical Conductivity and NMR Studies in Variable Equivalent Weight NAFION Membranes" Macromolecules, 29, 4944-4951 (1996).
Measurements of the electrical conductivity and proton and fluorine-19 NMR spin-lattice relaxation times (T1) in acid form NAFION 105, 117 and 120 conditioned at various levels of relative humidity have been carried out. Complex impedance studies were made along the plane of the polymer film at frequencies from 10 to 108 Hz at room temperature and pressures up to 0.3 GPa. The NMR measurements were made at room temperature and pressures up to 0.25 GPa. Both types of measurement were also carried out on various concentrations of sulfuric acid in water. The electrical conductivity decreases with increasing pressure for low water content acid solutions and low water content NAFION samples. This behavior (positive activation volumes) is that expected for "normal" liquids and for ions in polymers where the motion of the ions is determined by the host matrix. However, for high water contents, the reverse is true. The electrical conductivity increases with increasing pressure which gives rise to a negative activation volume. The results show that at high water contents, the electrical conductivity mechanism in NAFION is essentially identical to that for a dilute acid where the transport is controlled by the aqueous component. The activation volumes extracted from the proton NMR T1 data are in qualitative agreement with those obtained from the electrical conductivity measurements at intermediate and low water contents, suggesting that motion of the sulfonic acid-terminated pendant chains contribute to the conduction mechanism at low water contents.
HUDDLE, James R., Coauthor, "A Note on Benford's Law," Mathematics and Computer Education, 31, 66 (1997).
At first blush, one would think that if a number were chosen at random from a table, the probability that the first (or most significant) digit of that number will be k would be constant for all first digits k = 1, 2, ..., 9. Benford's Law states that the probability that the most significant digit is k is given by P(k) = log [(k+1)/k]. That is, the probability that the most significant digit of such a number is 1 is about 30%, that it is 2 is about 18%, ..., and that it is 9 is about 5%.
In an empirical test of Benford's Law, the frequencies of the most significant digit of 2000 numerical answers to problems given in the back of four physics and mathematics textbooks were tabulated and plotted as a function of the integers from 1 to 9. The chi-square statistic for these data was 12.0085, leading the authors to accept Benford's Law for homework problems with a high degree of confidence. The authors show that Benford's Law is valid for any collection of integers that has finite maximum value, and therefore that Benford's Law is to be expected for answers to homework problems.
HUDDLE, James R., "Eigenfunctions and Eigenvalues," Macmillan Encyclopedia of Physics, Macmillan, New York, p. 392, 1996.
In many problems in engineering and physics, it is required to find a function which is not only a solution to a specified differential equation, but also has a specified behavior on the boundaries of some region of space. Generally, such functions, called eigenfunctions, exist only for certain special values of one of the parameters in the differential equation. These special values of the parameter are called eigenvalues. In this article, the conditions under which eigenfunctions and eigenvalues can be found are reviewed, two theorems about the orthogonality of the eigenfunctions and the real-valuedness of the eigenvalues in certain important cases are presented, and the important role eigenfunctions and eigenvalues play in the theory of quantum mechanics is discussed.
HUDDLE, James R., "Ground State," Macmillan Encyclopedia of Physics, Macmillan, New York, p. 690, 1996.
In quantum mechanics, states of definite energy are called stationary states or allowed states. The stationary state for a particular system with the lowest possible energy is called the ground state for that system. In this article, the ground-state energies for several important quantum-mechanical systems are discussed.
HUDDLE, James R., "Van de Graaff Accelerator," Macmillan Encyclopedia of Physics Macmillan, New York, p. 1665, 1996.
An accelerator is a machine used to produce a beam of swiftly moving charged particles, either electrons or positively charged ions. Originally designed for nuclear and high-energy physics research, accelerators have found uses in studies of atomic and molecular structure, in materials science, and in medicine. One type of accelerator derives the energy to accelerate charged particles from an electrostatic generator developed by Robert J. Van de Graaff at Princeton University in 1929. This article discusses the principles of the operation and control of the Van de Graaff accelerator.
KATZ-STONE, Debora. M., Coauthor, "A Spectral Analysis of Two Compact Steep Spectrum Sources," Astrophysical Journal , 479, 258-267 (1997).
We have added new high-resolution Very Large Array (VLA) and Very Large Baseline Array (VLBA) data of two compact steep-spectrum sources (CSSs)(3C 67 and 3C 190) to existing data. We find that both sources have a complex spectral structure that is not completely resolved with these data.
A standard aging analysis of 3C 190 predicts an unusually steep injection index of -0.8 and a young age. If CSSs are found to have steep injection indices in general, then it suggests that they are not simply younger, smaller version of large radio sources, but a different type of object. Another possibility is that the injection index is -0.5 and that the superposition of aged spectral components makes the injection index appear steeper. Whichever explanation is appropriate, interpretation of spectral data in such conventional terms as aging must be made cautiously.
KATZ-STONE, Debora M., "Get Serious on Science" 21AUG96 USA Today
This general audience article encourages adults to get involved with science education. Adults with a genuine interest in science can encouraged children to consider a future in scientific pursuit.
STALLWORTH, Phillip, Assistant Professor, Coauthor, "X-ray Absorption and Magnetic Resonance Spectroscopic Studies of LixV6O3," accepted to J. Appl. Phys, 1997.
Polycrystalline LixV6O3, samples, 0.5 < x < 6, were prepared by chemical intercalation in n-butyl lithium and investigated spectroscopically by x-ray absorption, electron paramagnetic resonance (EPR), and 7Li solid state nuclear magnetic resonance (NMR). Both the EPR results and the vanadium K-edge x-ray absorption fine structure spectra show that the average oxidation state of the vanadium decreases with the addition of lithium. Furthermore, the x-ray results provide evidence of lithium-deficient and oxygen-deficient impurity phases. The local symmetry of the vanadium atoms first decreases with increasing x, from 0 < x < 1, and then increases with increasing x as the vanadium octahedral environment becomes less distorted. These changes are revealed by both the intensity of the first V-O peak in the radial distribution function and by the decrease in the x-ray absorption pre-edge intensity. However, structural correlations beyond the nearest neighbor atoms rapidly decrease with increasing lithium content above x = 1.5, reflecting increased disorder. The observed increase in V-O distance implies a modest lattice expansion with intercalated lithium, from 1.93 angstroms at x = 0 (in agreement with x-ray diffraction results) to 2.02 angstroms at x = 5. Variable temperature 7Li NMR linewidth and spin-lattice relaxation measurements demonstrate that, dynamic processes govern the spin-lattice relaxation when 0.5 < x < 2; but paramagnetic (as well as homonuclear) dipolar interactions have a pronounced effect in reducing the spin-lattice relaxation time as lithium content is increased beyond x = 2. Analysis of the 7Li NMR lineshape verifies the presence of impurity phases. Paramagnetic and diamagnetic chemical shifts yield evidence for local magnetic ordering which accompany the structural changes upon lithium intercalation.
STALLWORTH, Phillip, Assistant Professor, Coauthor, "Electrical Conductivity and NMR Studies of Methanol/Water Mixtures in NAFION Membranes," accepted to Solid State Ionics., 1997.
Complex impedance studies have been carried out in acid form NAFION 117 treated with various amounts of methanol and methanol-water mixtures. At room temperature and atmospheric pressure the conductivity for NAFiON treated with "pure" methanol is about a factor of ten less than for NAFION which contains the same wt.% of water. In samples treated with water-methanol mixtures, the conductivity is lower than for samples having the same total wt.% of water. However, for low mixed fluid wt.% the conductivity is significantly higher than for samples with the same amount of water, only, as was in the mix. This enhancement of conductivity over that for the corresponding water uptake is attributed to a plasticizing effect of the methanol facilitating the segmental motion of the polymer. At higher water concentrations, the conductivity is generally lower in the mixed solution-treated samples than in samples treated with the corresponding amount of water. This is to be expected since in this regime, proton conduction occurs in fluid-rich regions, which in the solution case includes a large fraction of methanol. For a 40 wt.% 1.4:1 molar ratio film, the studies were carried out at pressures up to 0.3 GPa. It is found that the electrical conductivity decreases with increasing pressure. Both the electrical conductivity and the activation volume are similar to the result for NAFION containing the same amount of water only. Deuteron NMR spin-lattice relaxation measurements of isotopically enriched methalol/water mixtures in NAFION 117 at elevated pressure demonstrate greater molecular-level interactions between methanol and NAFION than between water and NAFION. This is consistent with the plasticizing effect observed in the conductivity results.
TANKERSLEY, Lawrence L., "Real-Time Optical Debris Monitoring", Integrated Monitoring, Diagnostics, and Failure Prevention Meeting Proceedings, 51st Meeting of the Society for Machinery Failure Prevention Technology (MFPT).1, pp. 443-448, (1997, Virginia Beach,VA.).
The status of two optical debris monitoring programs is described. The optical debris monitors are directed at developing on line technology for identifying type and severity of faults in machinery through measurement of size, shape and morphology of debris particles in real time. Operational characteristics of the monitors in two different size ranges is described.
WINTERSGILL, Mary C., Professor, Coauthor, "High pressure NMR and electrical conductivity studies of gel electrolytes based on poly(acrylonitrile)" Solid State Ionics, 85, 173-179 (1996).
The effect of high pressure on electrical conductivity and NMR in gels prepared from lithium or sodium perchlorate, ethylene carbonate, dimethyl carbonate and poly(acrylonitrile) (PAN) has been determined. The corresponding liquids were also studied. Complex impedance studies at frequencies from 10 to 108 Hz and NMR measurements of T1 were carried out as a function of pressure up to 0.25 GPa. Activation volumes for NMR relaxation and ionic conductivity were calculated from the variable pressure data. Both activation volumes were found to be approximately the same in the liquids. For the gels, however, the NMR activation volumes are the same or lower than for the liquid while the electrical conductivity pressure dependencies are larger. The implications of these results are discussed in terms of possible effects of the PAN on the ionic solvation shell.
WINTERSGILL, M. C., Professor, Coauthor, "High Pressure Electrical Conductivity and NMR Studies in Variable Equivalent Weight NAFION Membranes" Macromolecules, 29, 4944-4951 (1996).
Measurements of the electrical conductivity and proton and fluorine-19 NMR spin-lattice relaxation times (T1) in acid form NAFION 105, 117 and 120 conditioned at various levels of relative humidity have been carried out. Complex impedance studies were made along the plane of the polymer film at frequencies from 10 to 108 Hz at room temperature and pressures up to 0.3 GPa. The NMR measurements were made at room temperature and pressures up to 0.25 GPa. Both types of measurement were also carried out on various concentrations of sulfuric acid in water. The electrical conductivity decreases with increasing pressure for low water content acid solutions and low water content NAFION samples. This behavior (positive activation volumes) is that expected for "normal" liquids and for ions in polymers where the motion of the ions is determined by the host matrix. However, for high water contents, the reverse is true. The electrical conductivity increases with increasing pressure which gives rise to a negative activation volume. The results show that at high water contents, the electrical conductivity mechanism in NAFION is essentially identical to that for a dilute acid where the transport is controlled by the aqueous component. The activation volumes extracted from the proton NMR T1 data are in qualitative agreement with those obtained from the electrical conductivity measurements at intermediate and low water contents, suggesting that motion of the sulfonic acid-terminated pendant chains contribute to the conduction mechanism at low water contents.
ENGLE, I. M., Professor, "Jovian Magnetosphere, Including the Dayside Solar Wind Interaction and the Khurana Jovian Magnetodisk," Magnetospheres of the Outer Planets, Boulder CO, 17 March 1997.
ERTEL, J. P., Associate Professor, "W22: Introduction to Interactive Physics III and Its Use in the Undergraduate Classroom/Laboratory," Winter Meeting of the American Association of Physics Teachers, Phoenix, AZ, 4-9 January 1997.
ERTEL, J. P., Associate Professor, "W33: Intermediate and Advanced Interactive Physics III and Its Use in the Undergraduate Classroom/Laboratory," Summer Meeting of the American Association of Physics Teachers , Boulder, CO, 4-9 August 1997.
HUDDLE, J. R., Associate Professor, "Total Solar Eclipses: Expeditions to Peru and to India." Westminster Astronomical Society, Westminster, MD, 12 June 1996.
HUDDLE, J. R., Associate Professor, "Solar Eclipses in Peru and in India," Physics Department Colloquium, Annapolis, MD, 16 October 1996.
FONTANELLA, J. J., Professor, "Complex Impedance Measurements on NAFION," Fifth International Symposium on Polymer Electrolytes, Uppsala, Sweden, 11-16 August 1996.
FONTANELLA, J. J., Professor, "Electrical Conductivity and NMR Studies of Methanol/Water Mixtures in NAFION Membranes," Fifth International Symposium on Polymer Electrolytes, Uppsala, Sweden, 11-16 August 1996.
FONTANELLA, J. J., Professor, "High Pressure Electrical Conductivity Studies of Acid Doped Polybenzimidazole," Fifth International Symposium on Polymer Electrolytes, Uppsala, Sweden, 11-16 August 1996.
FONTANELLA, J. J., Professor, "Electrical Transport in Fuel Cell and Battery Components," ONR Electrochemistry Review, Atlanta, GA, 3-4 April 1997.
KATZ-STONE, D.M., Assistant Professor, "The Evolution of the Relativistic Particles and the Structure of the Magnetic Field in Extragalactic Radio Sources," American Astronomical Societal 188th Conference, Madison, WI, 9-13June 1996.
KATZ-STONE, D.M., Assistant Professor, "Spectral Tomography Reveals the Hidden Structures of Radio Sources," Hubble Space Telescope Science Institute, Baltimore, MD, 26 September 1996.
KATZ-STONE, D.M., Assistant Professor, "A Spectral Analysis of 3C67 and 3C190," IAU 164th Conference, Socorro, NM, 21-26 April 1997.
KORMAN, Murray S., Professor, "Musical Acoustics Demonstrations Play A Role In Teaching Underwater Acoustics And Sonar," 133th meeting of the Acoust. Soc. of Am., State College, PA, 15 - 20 June 1997.
KORMAN, Murray S., Professor, "Computer Analysis Of The Resonant Scattering Of Sound By A Bubbly Fluid Encapsulated By A Submerged Spherical Shell," 133th meeting of the Acoust. Soc. of Am., State College, PA, 15 - 20 June 1997.
KORMAN, Murray S., Professor, "Design and Development of PC-IMAT: Teaching Strategies For Acoustical Oceanography," 133th meeting of the Acoust. Soc. of Am.,State College, PA, 15 - 20 June, 1997.
KORMAN, Murray S., Professor, "Underwater Sound Radiation from a Spherical Bubble Cloud Encapsulated by a Thin Spherical Shell," 133th meeting of the Acoust. Soc. of Am., State College, PA, 15 - 20 June 1997.
NOVO-GRADAC, A.M., Assistant Professor, "An Introduction to Lasers," Girls and Women in Science Conference, Beloit College, Beloit, WI, 4 April 1997.
SCHNEIDER, C. S., Professor, "The Physics of Magnetic Signatures," Mine Warfare Symposium, Monterey CA, 18 November 1996.
STALLWORTH, P. E., Assistant Professor, "X-ray Absorption and Magnetic Resonance Spectroscopic Studies of LixV6O3," Gordon Research Conference on Solid State Ionics, New London, NH, 16-21 June 1996.
STALLWORTH, P. E., Assistant Professor, "NMR and Electrical Conductivity Studies of Methanol/Water Mixtures in NAFION Membranes," DARPA Fuel Cell Review, Arlington, VA, 14-15 November 1996.
STALLWORTH, P. E., Assistant Professor, "X-ray Absorption and Magnetic Resonance Spectroscopic Studies of LixV6O3," Meeting of the American Physical Society, Kansas City, MO, 17-21 March 1997.
STALLWORTH, P. E., Assistant Professor, "NMR Studies of Cathode Materials and Ion-Conducting Membranes," ONR Electrochemistry Program Review, Atlanta, GA, 3-4 April 1997.
TANKERSLEY, L. L., "Real-Time Optical Debris Monitoring," 51st Meeting of the Society for Machinery Failure Prevention Technology (MFPT), Virginia Beach,VA, 14-18 April 1997.
VANHOY, J. R., Associate Professor, "Nuclear Structure Trends in the Tellurium Isotopes," Conference Program and Abstract Book, p 363, Eleventh National Conference on Undergraduate Research NCUR-97, Austin, TX, 24-26 April 1997.
VANHOY, J. R., Associate Professor, "124Te Spectroscopic Studies Using (n,n') Coincidence Techniques," April Meeting of the American Physical Society, Washington, DC, 18-21 April 1997
VANHOY, J. R., Associate Professor, "Decay Properties and Lifetimes of States in 124Te from (n,n') Reaction Studies," Texas Section Meeting of the American Physical Society, Houston, TX, 13-15 March 97.
WINTERSGILL, M. C., Professor, "Complex Impedance Measurements on NAFION," Fifth International Symposium on Polymer Electrolytes, Uppsala, Sweden, 11-16 August 1996.
WINTERSGILL, M. C., Professor, "Electrical Conductivity and NMR Studies of Methanol/Water Mixtures in NAFION Membranes," Fifth International Symposium on Polymer Electrolytes, Uppsala, Sweden, 11-16 August 1996.
WINTERSGILL, M. C., Professor, "High Pressure Electrical Conductivity Studies of Acid Doped Polybenzimidazole," Fifth International Symposium on Polymer Electrolytes, Uppsala, Sweden, 11-16 August 1996.