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Wind-induced Ground-surface Pressures Around a Single-Family House

Description: Wind induces a ground-surface pressure field around a building that can substantially affect the flow of soil gas and thereby the entry of radon and other soil-gas contaminants into the building. To quantify the effect of the wind-induced groundsurface pressure field on contaminant entry rates, the mean ground-surface pressure field was experimentally measured in a wind tunnel for several incidence angles of the wind, two atmospheric boundary layers, and two house geometries. The experimentally… more
Date: February 1, 1996
Creator: Riley, W. J.; Gadgil, A. J. & Nazaroff, W. W.
Partner: UNT Libraries Government Documents Department
open access

Bayesian Prediction of Mean Indoor Radon Concentrations for Minnesota Counties

Description: Past efforts to identify areas with higher than average indoor radon concentrations by examining the statistical relationship between local mean concentrations and physical parameters such as the soil radium concentration have been hampered by the variation in local means caused by the small number of homes monitored in most areas. In this paper, indoor radon data from a survey in Minnesota are analyzed to minimize the effect of finite sample size within counties, to determine the true county-t… more
Date: February 1, 1996
Creator: Price, P. N.; Nero, A. V. & Gelman, A.
Partner: UNT Libraries Government Documents Department
open access

Nonlinear spatio-temporal interactions and neural connections in human vision using transient and M-sequence stimuli

Description: Reciprocal connections, in essence, are the dynamic wiring (connections) of the neural network circuitry. Given the high complexity of the neural circuitry in the human brain, it is quite a challenge to study the dynamic wiring of highly parallel and widely distributed neural networks. The measurements of stimulus evoked coherent oscillations provide indirect evidence of dynamic wiring. In this study, in addition to the coherent oscillation measurements, two more techniques are discussed for te… more
Date: February 1, 1996
Creator: Chen, H. W.; Aine, C. J.; Flynn, E. R. & Wood, C. C.
Partner: UNT Libraries Government Documents Department
open access

Deformation and Velocity Measurements at Elevated Temperature in a Fractured 0.5 M Block of Tuff

Description: This paper presents preliminary results of laboratory tests conducted on small block samples of Topopah Spring tuff, in support of the Yucca Mountain Site Characterization Project. The overall objective of these tests is to investigate the thermal-mechanical, thermal-hydrological, and thermal-chemical response of the rock to conditions similar to the near-field environment (NFE) of a potential nuclear waste repository. We present preliminary results of deformation and elastic wave velocity meas… more
Date: February 1, 1996
Creator: Blair, S. C. & Berge, P. A.
Partner: UNT Libraries Government Documents Department
open access

Richtmyer-Meshkov instability experiments on the Nova laser from nonlinear initial perturbations

Description: We present the results from a series of experiments recently completed on the Nova laser studying the growth of the Richtmyer-Meshkov instability from an initially nonlinear perturbation. These are the first experimental measurements of the time-dependent mixing of materials at a shocked interface from a high-amplitude, short-wavelength perturbation in a high Mach number regime. The experiments were simulated using CALE, a two-dimensional arbitrary Lagrangian-Eulerian hydrodynamics code. The ca… more
Date: February 1, 1996
Creator: Peyser, T. A.; Miller, P. L.; Stry, P. E.; Budil, K. S. & Burke, E. W.
Partner: UNT Libraries Government Documents Department
open access

Development of a force specification for a force-limited random vibration test

Description: Vibration testing, techniques have been developed and employed that reduce the overtesting caused by the essentially infinite mechanical impedance of the shaker in conventional vibration tests. With these ``force-limiting`` techniques, two vibration test specifications are used: the conventional acceleration specification, and an interface force specification. The vibration level of the shake table is controlled such that neither the table acceleration nor the force transmitted to the test item… more
Date: February 1, 1996
Creator: Stevens, R. Robert
Partner: UNT Libraries Government Documents Department
open access

Search for earth mass planets and dark matter too

Description: Gravitational microlensing is known for baryonic dark matter searches. Here we show that microlensing also provides a unique tool for the detection of low mass planets (such as earths and neptunes) from the ground. A planetary system forms a binary lens (or, a multi-point lens), and we can determine the mass ratio of the planet with respect to the star and relative distance (= separation/Einstein ring radius) between the star and planet. Such a microlensing planet search project requires a {app… more
Date: February 1, 1996
Creator: Rhie, S.H. & Bennett, D.P.
Partner: UNT Libraries Government Documents Department
open access

TCP performance in ATM networks: ABR parameter tuning and ABR/UBR comparisons

Description: This paper explores two issues on TOP performance over ATM networks: ABR parameter tuning and performance comparison of binary mode ABR with enhanced UBR services. Of the fifteen parameters defined for ABR, two parameters dominate binary mode ABR performance: Rate Increase Factor (RIF) and Rate Decrease Factor (RDF). Using simulations, we study the effects of these two parameters on TOP over ABR performance. We compare TOP performance with different ABR parameter settings in terms of through-pu… more
Date: February 27, 1996
Creator: Chien Fang & Lin, A.
Partner: UNT Libraries Government Documents Department
open access

QCD tests at CDF

Description: We present results for the inclusive jet cross section and the dijet mass distribution. The inclusive cross section and dijet mass both exhibit significant deviations from the predictions of NLO QCD for jets with E{sub T}>200 GeV, or dijet masses > 400 GeV/c{sup 2}. We show that it is possible, within a global QCD analysis that includes the CDF inclusive jet data, to modify the gluon distribution at high x. The resulting increase in the jet cross-section predictions is 25-35%. Owing to the pres… more
Date: February 1, 1996
Creator: Kovacs, E.
Partner: UNT Libraries Government Documents Department
open access

Hierarchical rendering of trees from precomputed multi-layer z-buffers

Description: Chen and Williams show how precomputed z-buffer images from different fixed viewing positions can be reprojected to produce an image for a new viewpoint. Here images are precomputed for twigs and branches at various levels in the hierarchical structure of a tree, and adaptively combined, depending on the position of the new viewpoint. The precomputed images contain multiple z levels to avoid missing pixels in the reconstruction, subpixel masks for anti-aliasing, and colors and normals for shadi… more
Date: February 1, 1996
Creator: Max, N.
Partner: UNT Libraries Government Documents Department
open access

Energy use of icemaking in domestic refrigerators

Description: This study was designed to develop and test a procedure to measure the electrical consumption of ice making in domestic refrigerators. The Department of Energy (DOE) test procedure was modified to include the energy used for icemaking in conventional refrigerators and those equipped with automatic icemakers. The procedure assumed that 500 grams of ice would be produced daily. Using the new test procedure and the existing DOE test (as a benchmark), four refrigerators equipped with automatic icem… more
Date: February 1, 1996
Creator: Meier, A. & Martinez, M.S.
Partner: UNT Libraries Government Documents Department
open access

Extraction of modal parameters with the aid of predicted analytical mode shapes

Description: The extraction of the modal parameters for closely spaced modes in the frequency domain is a common problem. However, it is made more difficult if the damping for the closely spaced modes is high. Data from a structure with more than three percent viscous damping is presented which exhibits this phenomenon. Traditional experimental techniques failed to identify all the modal parameters of three closely spaced modes. Mode shapes from an analytical model are manipulated to produce a modal filter … more
Date: February 1, 1996
Creator: Mayes, R.L. & Carne, T.G.
Partner: UNT Libraries Government Documents Department
open access

Clean enough for industry? An airborne geophysical case study

Description: Data from two airborne geophysical surveys of the Department of Energy`s Oak Ridge Reservation (ORR) were extremely valuable in deciding whether a 1000-acre (400 hectare) parcel of the ORR should be released to the City of Oak Ridge for industrial development. Our findings, based on electromagnetic and magnetic data, were incorporated in the federally mandated Environmental Assessment Statement (EAS), and in general supported claims that this land was never used as a hazardous waste disposal si… more
Date: February 1, 1996
Creator: Nyquist, J.E. & Beard, L.P.
Partner: UNT Libraries Government Documents Department
open access

On persistence interfaces for scientific data stores

Description: A common dilemma among builders of large scientific data stores is whether to use a lightweight object persistence manager or a genuine object-oriented database. There are often good reasons to consider each of these strategies; a few are described in this paper. Too often, however, electing to use a lightweight approach has meant programming to an interface that is entirely different than that expected by commercial object-oriented databases. With the emergence of object database standards, it… more
Date: February 9, 1996
Creator: Malon, D. M. & May, E. N.
Partner: UNT Libraries Government Documents Department
open access

Testing experience with the FORTE` satellite

Description: FORTE is a small 193 kg (425 lb) satellite that will be placed in orbit with a Pegusus-XL launch vehicle in late 1996. The primary FORTE Program objective is to detect and record atmospheric bursts of electromagnetic radiation. The satellite structure is fabricated primarily with graphite epoxy. This Paper summarizes the testing/analysis philosophy for the FORTE satellite structure and describes how preliminary engineering module structural tests affected the final design. Several novel design … more
Date: February 1, 1996
Creator: Butler, T. A.
Partner: UNT Libraries Government Documents Department
open access

Techniques for increasing output power from mode-locked semiconductor lasers

Description: Mode-locked semiconductor lasers have drawn considerable attention as compact, reliable, and relatively inexpensive sources of short optical pulses. Advances in the design of such lasers have resulted in vast improvements in pulsewidth and noise performance, at a very wide range of repetition rates. An attractive application for these lasers would be to serve as alternatives for large benchtop laser systems such as dye lasers and solid-state lasers. However, mode-locked semiconductor lasers hav… more
Date: February 1, 1996
Creator: Mar, A. & Vawter, G. A.
Partner: UNT Libraries Government Documents Department
open access

Runoff and erosion from a rapidly eroding pinyon-juniper hillslope

Description: The dramatic acceleration of erosion associated with the expansion of pinyon-juniper woodlands over the past 100 years has been a widely recognized but poorly understood phenomenon. A more complete understanding will come only through long-term observations of erosion and related factors. To this end, we are conducting a study of a small (1-ha) catchment in a rapidly eroding pinyon-juniper woodland. Since July 1993, we have been collecting data on runoff, erosion, and weather conditions in the … more
Date: February 1, 1996
Creator: Wilcox, B.P.; Davenport, D. W.; Pitlick, J. & Allen, C.D.
Partner: UNT Libraries Government Documents Department
open access

Ultrasonic removal of organic deposits and polymer induced formation damage

Description: Experiments were conducted that evaluate the feasibility of using high intensity acoustic sources to remove near wellbore formation damage caused by organic deposits (paraffins and asphaltenes) and polymers (HEC). It is shown that mechanical agitation provided by the acoustic waves effectively re-suspends the paraffin and restores the effective permeability of the core to oil to its undamaged condition in a relatively short period of time. The depth of treatment is approximately 12 to 15 cm. Th… more
Date: February 1, 1996
Creator: Roberts, P.M. & Sharma, M.M.
Partner: UNT Libraries Government Documents Department
open access

Computer modeling of electromagnetic fields and fluid flows for edge containment in continuous casting

Description: A computer model was developed to predict eddy currents and fluid flows in molten steel. The model was verified by comparing predictions with experimental results of liquid-metal containment and fluid flow in electromagnetic (EM) edge dams (EMDs) designed at Inland Steel for twin-roll casting. The model can optimize the EMD design so it is suitable for application, and minimize expensive, time-consuming full-scale testing. Numerical simulation was performed by coupling a three-dimensional (3-D)… more
Date: February 1, 1996
Creator: Chang, F.C.; Hull, J.R.; Wang, Y.H. & Blazek, K.E.
Partner: UNT Libraries Government Documents Department
open access

An inverse problem by boundary element method

Description: Boundary Element Methods (BEM) have been established as useful and powerful tools in a wide range of engineering applications, e.g. Brebbia et al. In this paper, we report a particular three dimensional implementation of a direct boundary integral equation (BIE) formulation and its application to numerical simulations of practical polymer processing operations. In particular, we will focus on the application of the present boundary element technology to simulate an inverse problem in plastics p… more
Date: February 1, 1996
Creator: Tran-Cong, T.; Nguyen-Thien, T. & Graham, A. L.
Partner: UNT Libraries Government Documents Department
open access

Effect of high magnetic fields on orientation and properties of liquid crystalline thermosets

Description: In this report we provide the first description of the orientation of liquid crystalline thermosets (LCT`s) in field strengths of up to 18 T, as well as the first report of tensile properties for both unoriented and oriented LCT`S. The LCT we have chosen for study is the diglycidyl ether of dihydroxy-a-methylstilbene cured with the diamine, sulfanilamide. Orientation in magnetic fields leads to an increase of almost three times the modulus compared to the unoriented material. These values are m… more
Date: February 1, 1996
Creator: Smith, Mark E.; Benicewicz, Brian C.; Douglas, Elliot P.; Earls, Jim D. & Priester, Ralph D., Jr.
Partner: UNT Libraries Government Documents Department
open access

Preliminary shielding estimates for the proposed Oak Ridge National Laboratory (ORNL) Radioactive Ion Beam Facility (RIBF)

Description: The Oak Ridge National Laboratory (ORNL) has proposed designing and implementing a new target-ion source for production and injection of negative radioactive ion beams into the Hollifield tandem accelerator. This new facility, referred to as the Radioactive Ion Beam Facility (RIBF), will primarily be used to advance the scientific communities` capabilities for performing state-of-the-art cross-section measurements. Beams of protons or other light, stable ions from the Oak Ridge Isochronous Cycl… more
Date: February 1, 1996
Creator: Johnson, J.O.; Gabriel, T.A. & Lillie, R.A.
Partner: UNT Libraries Government Documents Department
open access

Approximation algorithms for NEXTtime-hard periodically specified problems and domino problems

Description: We study the efficient approximability of two general class of problems: (1) optimization versions of the domino problems studies in [Ha85, Ha86, vEB83, SB84] and (2) graph and satisfiability problems when specified using various kinds of periodic specifications. Both easiness and hardness results are obtained. Our efficient approximation algorithms and schemes are based on extensions of the ideas. Two of properties of our results obtained here are: (1) For the first time, efficient approximati… more
Date: February 1, 1996
Creator: Marathe, M. V.; Hunt, H. B., III; Stearns, R. E. & Rosenkrantz, D. J.
Partner: UNT Libraries Government Documents Department
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