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The dipole observed in the COBE DMR 4 year data (open access)

The dipole observed in the COBE DMR 4 year data

None
Date: January 18, 1996
Creator: Lineweaver, C. H.; Tenorio, L.; Smoot, G. F. & Keegstra, P.
System: The UNT Digital Library
Medical Waste Co-Firing Comes of Age (open access)

Medical Waste Co-Firing Comes of Age

In early 1992 DONLEE Technologies, Inc., in cooperation with the Department of Energy Fossil Energy Program, completed pilot testing of simulated non-infectious waste combustion, co-fired with coal, at its test facility in York, Pennsylvania. The goal of this testing was to demonstrate the ability of fluidized bed combustion to completely destruct medical waste with minimized dioxin emissions. The test facility is a full scale circulating fluidized bed unit with a maximum heat input capability of ten million BTU per hour. The tests showed that the circulating fluidized bed system is ideally suited to meet the medical/infectious waste destruction needs of the health care industry. The dioxin emission levels proved to be significantly lower than those from presently operating MWIS. Based on the successful test results, a cooperative agreement with the Department of Energy Fossil Energy Power Systems, DONLEE Technologies, and the Veterans Administration was reached to design, construct, and test a demonstration unit at the Veterans Administration Medical Center in Lebanon, Pennsylvania. Plant design and construction was started in 1993, with DONLEE Technologies functioning as both the technology supplier and the plant EPC contractor. After some delay the construction of the demonstration unit finally reached completion in the spring of …
Date: December 18, 1996
Creator: Smith-Berntson, K. & Stuart, J. M.
System: The UNT Digital Library
Broadband acoustic source processing in a noisy shallow ocean environment (open access)

Broadband acoustic source processing in a noisy shallow ocean environment

Acoustic sources found in the ocean environment are spatially complex and broadband, complicating the analysis of received acoustic data considerably. A model-based approach is developed for a broadband source in a shallow ocean environment characterized by a normal-mode propagation model. Here we develop the optimal Bayesian solution to the broadband pressure-field enhancement and modal function extraction problem.
Date: July 18, 1996
Creator: Candy, J. V. & Sullivan, E. J.
System: The UNT Digital Library
3-D electromagnetic modeling of wakefields in accelerator components (open access)

3-D electromagnetic modeling of wakefields in accelerator components

We discuss the use of 3-D finite-difference time-domain (FDTD) electromagnetic codes for modeling accelerator components. Computational modeling of cylindrically symmetric structures such as induction accelerator cells has been very successful in predicting the wake potential and wake impedances of these structures, but full 3-D modeling of complex structures has been limited due to substantial computer resources required for a full 3-D model. New massively parallel 3-D time domain electromagnetic codes now under development using conforming unstructured meshes allow a substantial increase in the geometric fidelity of the structures being modeled. Development of these new codes are discussed in context of applicability to accelerator problems. Various 3-D structures are tested with an existing cubical cell FDTD code and wake impedances compared with simple analytic models for the structures; results will be used as benchmarks for testing the new time time domain codes. Structures under consideration include a stripline beam position monitor as well as circular and elliptical apertures in circular waveguides. Excellent agreement for monopole and dipole impedances with models were found for these structures below the cutoff frequency of the beam line.
Date: September 18, 1996
Creator: Poole, B.R.; Caporaso, G.J.; Ng, Wang C.; Shang, C.C. & Steich, D.
System: The UNT Digital Library
Understanding the nonlinear beam dynamics of the Advanced Light Source (open access)

Understanding the nonlinear beam dynamics of the Advanced Light Source

Frequency map analysis is used to study the single particle transverse beam dynamics in ALS. The maps, which provide details about the diffusion of orbits and limits on long term stability, are generated by a postprocessor attached to a tracking code. This paper describes the method and shows how the map is changed when the 12- fold symmetry of the linear lattice is perturbed by including measured magnetic field imperfections. Also the long term stability of orbits that reside in regions of large diffusion is studied.
Date: September 18, 1996
Creator: Robin, D. & Laskar, J.
System: The UNT Digital Library
Crystalline structure in the confined-deconfined mixed phase: Neutron stars as an example (open access)

Crystalline structure in the confined-deconfined mixed phase: Neutron stars as an example

We review the differences in first order phase transition of single and multi-component systems, and then discuss the crystalline structure expected to exist in the mixed confined deconfined phase of hadronic matter. The particular context of neutron stars is chosen for illustration. The qualitative results are general and apply for example to the vapor-liquid transition in subsaturated asymmetric nuclear matter.
Date: April 18, 1996
Creator: Glendenning, N.K.
System: The UNT Digital Library
Environmental waste site characterization utilizing aerial photographs, remote sensing, and surface geophysics (open access)

Environmental waste site characterization utilizing aerial photographs, remote sensing, and surface geophysics

Six different techniques were used to delineate 40 year old trench boundary at Los Alamos National Laboratory. Data from historical aerial photographs, a magnetic gradient survey, airborne multispectral and thermal infra-red imagery, seismic refraction, DC resistivity, and total field magnetometry were utilized in this process. Each data set indicated a southern and northern edge for the trench. Average locations and 95% confidence limits for each edge were determined along a survey line perpendicular to the trench. Trench edge locations were fairly consistent among all six techniques. Results from a modeling effort performed with the total magnetic field data was the least consistent. However, each method provided unique and complementary information, and the integration of all this information led to a more complete characterization of the trench boundaries and contents.
Date: April 18, 1996
Creator: Pope, P.; Van Eeckhout, E.; Rofer, C.; Baldridge, S.; Ferguson, J.; Jiracek, G. et al.
System: The UNT Digital Library
Divertor characterization experiments (open access)

Divertor characterization experiments

Recent DIII-D experiments with enhanced Scrape-off Layer (SOL) diagnostics permit detailed characterization of the SOL and divertor plasma under various operating conditions. We observe two distinct plasma modes: attached and detached divertor plasmas. Detached plasmas are characterized by plate temperatures of only 1 to 2 eV. Simulation of detached plasmas using the UEDGE code indicate that volume recombination and charge exchange play an important role in achieving detachment. When the power delivered to the plate is reduced by enhanced radiation to the point that recycled neutrals can no longer be efficiently ionized, the plate temperature drops from around 10 eV to 1-2 eV. The low temperature region extends further off the plate as the power continues to be reduced, and charge exchange processes remove momentum, reducing the plasma flow. Volume recombination becomes important when the plasma flow is reduced sufficiently to permit recombination to compete with flow to the plate.
Date: June 18, 1996
Creator: Porter, G. D.; Allen, S.; Fenstermacher, M.; Hill, D.; Brown, M.; Jong, R. A. et al.
System: The UNT Digital Library
A technique for determining the Poisson`s ratio of thin films (open access)

A technique for determining the Poisson`s ratio of thin films

The theory and experimental approach for a new technique used to determine the Poisson`s ratio of thin films are presented. The method involves taking the ratio of curvatures of cantilever beams and plates micromachined out of the film of interest. Curvature is induced by a through-thickness variation in residual stress, or by depositing a thin film under residual stress onto the beams and plates. This approach is made practical by the fact that the two curvatures air, the only required experimental parameters, and small calibration errors cancel when the ratio is taken. To confirm the accuracy of the technique, it was tested on a 2.5 {mu}m thick film of single crystal silicon. Micromachined beams 1 mm long by 100 {mu} wide and plates 700 {mu}m by 700 {mu}m were coated with 35 nm of gold and the curvatures were measured with a scanning optical profilometer. For the orientation tested ([100] film normal, [011] beam axis, [0{bar 1}1] contraction direction) silicon`s Poisson`s ratio is 0.064, and the measured result was 0.066 {+-} 0.043. The uncertainty in this technique is due primarily to variation in the measured curvatures, and should range from {+-} 0.02 to 0.04 with proper measurement technique.
Date: April 18, 1996
Creator: Krulevitch, P.
System: The UNT Digital Library
Muon muon collider: Feasibility study (open access)

Muon muon collider: Feasibility study

A feasibility study is presented of a 2 + 2 TeV muon collider with a luminosity of L = 10{sup 35} cm{sup {minus}2} s{sup {minus}1}. The resulting design is not optimized for performance, and certainly not for cost; however, it does suffice--the authors believe--to allow them to make a credible case, that a muon collider is a serious possibility for particle physics and, therefore, worthy of R and D support so that the reality of, and interest in, a muon collider can be better assayed. The goal of this support would be to completely assess the physics potential and to evaluate the cost and development of the necessary technology. The muon collider complex consists of components which first produce copious pions, then capture the pions and the resulting muons from their decay; this is followed by an ionization cooling channel to reduce the longitudinal and transverse emittance of the muon beam. The next stage is to accelerate the muons and, finally, inject them into a collider ring which has a small beta function at the colliding point. This is the first attempt at a point design and it will require further study and optimization. Experimental work will be needed to …
Date: June 18, 1996
Creator: unknown
System: The UNT Digital Library
2l-nl{prime} x-ray transitions from neonlike charge states of the row 5 metals with 39 {le} Z {le} 46 (open access)

2l-nl{prime} x-ray transitions from neonlike charge states of the row 5 metals with 39 {le} Z {le} 46

X-ray spectra of 2l-2l{prime} transitions with 3 {le} n {le} 12 in the row five transition metals zirconium (Z = 40), niobium (Z = 41), molybdenum (Z = 42) and palladium (Z = 46) from charge states around neonlike have been observed from Alcator C-Mod plasmas. Accurate wavelengths ({+-} .2 m{angstrom}) have been determined by comparison with neighboring argon, chlorine and sulfur lines with well known wavelengths. Line identifications have been made by comparison to ab initio atomic structure calculations, using a fully relativistic, parametric potential code. For neonlike ions, calculated wavelengths and oscillator strengths are tabulated for 2p-nd transitions in Y (Z = 39), Tc (Z = 43), Ru (Z = 44) and Rh (Z = 45) with n = 6 and 7. The magnitude of the configuration interaction between the (2p{sup 5}){sub 1/2}6d{sub 3/2} J = 1 level and the (2p{sup 5}){sub 3/2}7D{sub 5/2} J = 1 levels is demonstrated as a function of atomic number for successive neonlike ions. Measured spectra of selected transitions in the aluminum-, magnesium-, sodium- and fluorine like isosequences are also shown.
Date: March 18, 1996
Creator: Rice, J. E.; Terry, J. L.; Marmar, E. S.; Fournier, K. B.; Goldstein, W. H.; Finkenthal, M. et al.
System: The UNT Digital Library
Micro electromechanical systems (MEMS) for mechanical engineers (open access)

Micro electromechanical systems (MEMS) for mechanical engineers

The ongoing advances in Microelectromechanical Systems (MEMS) are providing man-kind the freedom to travel to dimensional spaces never before conceivable. Advances include new fabrication processes, new materials, tailored modeling tools, new fabrication machines, systems integration, and more detailed studies of physics and surface chemistry as applied to the micro scale. In the ten years since its inauguration, MEMS technology is penetrating industries of automobile, healthcare, biotechnology, sports/entertainment, measurement systems, data storage, photonics/optics, computer, aerospace, precision instruments/robotics, and environment monitoring. It is projected that by the turn of the century, MEMS will impact every individual in the industrial world, totaling sales up to $14 billion (source: System Planning Corp.). MEMS programs in major universities have spawned up all over the United States, preparing the brain-power and expertise for the next wave of MEMS breakthroughs. It should be pointed out that although MEMS has been initiated by electrical engineering researchers through the involvement of IC fabrication techniques, today it has evolved such that it requires a totally multi-disciplinary team to develop useful devices. Mechanical engineers are especially crucial to the success of MEMS development, since 90% of the physical realm involved is mechanical. Mechanical engineers are needed for the design of MEMS, …
Date: November 18, 1996
Creator: Lee, A. P., LLNL
System: The UNT Digital Library
Automation for on-line remote-control in-situ electron microscopy (open access)

Automation for on-line remote-control in-situ electron microscopy

We have developed and tested a multimedia system for remote operation of transmission electron microscopes and used it to control the Kratos 1500keV microscope in Berkeley during in-situ experiments.
Date: May 18, 1996
Creator: O'Keefe, M. A.; Parvin, B.; Owen, D.; Taylor, J.; Westmacott, K. H.; Johnston, W. et al.
System: The UNT Digital Library
CP violation in top physics at the NLC (open access)

CP violation in top physics at the NLC

Top quark is extremely sensitive to non-standard CP violating phases. General strategies for exposing different types of phases at the NLC are outlined. SUSY phase(s) cause PRA in t {yields} Wb. The transverse polarization of the {tau} in the reaction t {yields} b{tau}{nu} is extremely sensitive to a phase from the charged Higgs sector. Phase(s) from the neutral Higgs sector cause appreciable dipole moment effects and lead to sizable asymmetries in e{sup +}e{sup {minus}} {yields} t{anti t}H{sup 0} and e{sup +}e{sup {minus}} {yields} t{anti t}{nu}{sub e}{anti {nu}}{sub e}.
Date: September 18, 1996
Creator: Atwood, D. & Soni, A.
System: The UNT Digital Library