An infrastructure for passive network monitoring of application data streams (open access)

An infrastructure for passive network monitoring of application data streams

When diagnosing network problems, it is often desirable to have a view of traffic inside the network. In this paper we describe an infrastructure for passive monitoring that can be used to determine which segments of the network are the source of problems for an application data stream. The monitoring hosts are relatively low-cost, off-the-shelf PCs. A unique feature of the infrastructure is secure activation of monitoring hosts in the core of the network without direct network administrator intervention.
Date: March 1, 2003
Creator: Agarwal, Deb; Gonzalez, Jose Maria; Jin, Guojun & Tierney, Brian
System: The UNT Digital Library
Rates, Polarizations, and Asymmetries in Charmless Vector-Vector B Decays (open access)

Rates, Polarizations, and Asymmetries in Charmless Vector-Vector B Decays

With a sample of approximately 89 million B{bar B} pairs collected with the BABAR detector, they measure branching fractions, determine the degree of longitudinal polarization, and search for direct CP violation in the decays B{sup 0} {yields} {phi}K*{sup 0} and B{sup +} {yields} {phi}K*{sup +}. They perform a search for other charmless vector-vector B decays involving {rho} and K*(892) resonances and observe the decays B{sup +} {yields} {rho}{sup 0} K*{sup +} and B{sup +} {yields} {rho}{sup 0}{rho}{sup +}. The branching fractions are measured to be {Beta}({phi}K*{sup 0}) = (11.1{sub -1.2}{sup +1.3} {+-} 1.1) x 10{sup -6}, {Beta}({phi}K*{sup +}) = (12.1{sub -1.9}{sup +2.1} {+-} 1.5) x 10{sup -6}, {Beta}({rho}{sup 0} K*{sup +}) = (7.7{sub -2.0}{sup +2.1} {+-} 1.4) x 10{sup -6}, and {Beta}({rho}{sup 0}{rho}{sup +}) = (9.9{sub -2.5}{sup +2.6} {+-} 2.5) x 10{sup -6}. The longitudinal polarization fractions are measured to be {Lambda}{sub L}/{Lambda}({phi}K*{sup 0}) = 0.65 {+-} 0.07 {+-} 0.04 and {Lambda}{sub L}/{Lambda}({phi}K*{sup +}) = 0.46 {+-} 0.12 {+-} 0.05. They measure the charge asymmetries: {Alpha}{sub CP}({phi}K*{sup 0}) = +0.04 {+-} 0.12 {+-} 0.02 and {Alpha}{sub CP}({phi}K*{sup +}) = +0.16 {+-} 0.17 {+-} 0.04.
Date: March 11, 2003
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Gaillard, J.-M.; Hicheur, A.; Karyotakis, Y. et al.
System: The UNT Digital Library
Design and Performance of Capping Layers for EUV Multilayer Mirrors (open access)

Design and Performance of Capping Layers for EUV Multilayer Mirrors

The reflectance stability of multilayer coatings for extreme ultraviolet lithography (EUVL) in a commercial tool environment is of uttermost importance to ensure continuous exposures with minimum maintenance cost. We have made substantial progress in designing the protective capping layer coatings, understanding their performance and estimating their lifetimes based on accelerated electron beam and EUV exposure studies. Our current capping layer coatings have about 40 times longer lifetimes than Si-capped multilayer optics. Nevertheless, the lifetime of current Ru-capped multilayers is too short to satisfy commercial tool requirements and further improvements are essential.
Date: March 10, 2003
Creator: Bajt, S.; Chapman, H. N.; Nuygen, N.; Alameda, J.; Robinson, J. C.; Malinowski, M. et al.
System: The UNT Digital Library
Nanotechnology Based Environmentally Robust Primers (open access)

Nanotechnology Based Environmentally Robust Primers

An initiator device structure consisting of an energetic metallic nano-laminate foil coated with a sol-gel derived energetic nano-composite has been demonstrated. The device structure consists of a precision sputter deposition synthesized nano-laminate energetic foil of non-toxic and non-hazardous metals along with a ceramic-based energetic sol-gel produced coating made up of non-toxic and non-hazardous components such as ferric oxide and aluminum metal. Both the nano-laminate and sol-gel technologies are versatile commercially viable processes that allow the ''engineering'' of properties such as mechanical sensitivity and energy output. The nano-laminate serves as the mechanically sensitive precision igniter and the energetic sol-gel functions as a low-cost, non-toxic, non-hazardous booster in the ignition train. In contrast to other energetic nanotechnologies these materials can now be safely manufactured at application required levels, are structurally robust, have reproducible and engineerable properties, and have excellent aging characteristics.
Date: March 18, 2003
Creator: Barbee, T. W., Jr.; Gash, A. E.; Satcher, J. H. Jr. & Simpson, R. L.
System: The UNT Digital Library
The Effects of Radiation Induced Carbon Contamination on the Performance of an EUV Lithographic Optic (open access)

The Effects of Radiation Induced Carbon Contamination on the Performance of an EUV Lithographic Optic

Carbon deposition in EUVL is known to occur when optical surfaces in a hydrocarbon environment are exposed to EUV light. Carbon contamination on EUV optical elements affects both the absorption and phase of the reflected light. Because the carbon deposition alters the phase structure of the reflected EUV light it effectively alters the figure of these optics and, thus, the aberrations as well. Absorption by deposited carbon not only reduces throughput but also leads to apodisation of the pupil, which in turn affects imaging performance.
Date: March 9, 2003
Creator: Barty, A. & Goldberg, K.
System: The UNT Digital Library
The impact of nanoscience on heterogeneous catalysis (open access)

The impact of nanoscience on heterogeneous catalysis

Most catalysts consist of nanometer-sized particles dispersed on a high-surface area support. Advances in characterization methods have led to a molecular level understanding of the relationships between nanoparticle properties and catalytic performance. Together with novel approaches to nanoparticle synthesis, this knowledge is contributing to the design and development of new catalysts.
Date: March 3, 2003
Creator: Bell, Alexis T.
System: The UNT Digital Library
Adaptive low Mach number simulations of nuclear flame microphysics (open access)

Adaptive low Mach number simulations of nuclear flame microphysics

We introduce a numerical model for the simulation of nuclear flames in Type Ia supernovae. This model is based on a low Mach number formulation that analytically removes acoustic wave propagation while retaining the compressibility effects resulting from nuclear burning. The formulation presented here generalizes low Mach number models used in combustion that are based on an ideal gas approximation to the arbitrary equations of state such as those describing the degenerate matter found in stellar material. The low Mach number formulation permits time steps that are controlled by the advective time scales resulting in a substantial improvement in computational efficiency compared to a compressible formulation. We briefly discuss the basic discretization methodology for the low Mach number equations and their implementation in an adaptive projection framework. We present validation computations in which the computational results from the low Mach number model are compared to a compressible code and present an application of the methodology to the Landau-Darrieus instability of a carbon flame.
Date: March 20, 2003
Creator: Bell, J. B.; Day, M. S.; Rendleman, C. A.; Woosley, S. E. & Zingale, M. A.
System: The UNT Digital Library
Matrix model description of baryonic deformations (open access)

Matrix model description of baryonic deformations

We investigate supersymmetric QCD with N{sub c} + 1 flavors using an extension of the recently proposed relation between gauge theories and matrix models.The impressive agreement between the two sides provides a beautiful confirmation of the extension of the gauge theory-matrix model relation to this case.
Date: March 13, 2003
Creator: Bena, Iosif; Murayama, Hitoshi; Roiban, Radu & Tatar, Radu
System: The UNT Digital Library
Free-Electron Lasers Push Into New Frontiers (open access)

Free-Electron Lasers Push Into New Frontiers

From the early days of the development of free-electron lasers (FELs) the promise of high power and short wavelengths has tantalized physicists and other scientists. Recent developments in accelerator technologies and some new discoveries about the physics of FELs have allowed researchers to push the performance of FELs into new frontiers of high power, short wavelength, and ultra-short pulses. Spin-offs from the FELs have also opened up new radiation sources in the THz, X-ray and gamma ray wavelength ranges.
Date: March 1, 2003
Creator: Benson, Stephen V.
System: The UNT Digital Library
Poroelastic Analysis of Thomsen Parameters in Finely Layed VTI Media (open access)

Poroelastic Analysis of Thomsen Parameters in Finely Layed VTI Media

Thomsen's anisotropy parameters for weak elastic and poroelastic anisotropy are now commonly used in exploration, and can be conveniently expressed in terms of the layer averages of Backus. Although there are five effective shear moduli for any layered VTI medium, only one effective shear modulus for the layered system contains all the dependence of pore fluids on the elastic or poroelastic constants that can be observed in vertically polarized shear waves in VTI media. The effects of the pore fluids on this effective shear modulus can be substantial when the medium behaves in an undrained fashion, as might be expected at higher frequencies such a sonic and ultrasonic for well-logging or laboratory experiments, or at seismic frequencies for lower permeability regions of reservoirs.
Date: March 17, 2003
Creator: Berger, E. L.
System: The UNT Digital Library
The Astrophysics Simulation Collaboratory portal: A framework foreffective distributed research (open access)

The Astrophysics Simulation Collaboratory portal: A framework foreffective distributed research

We describe the motivation, architecture, and implementation of the Astrophysics Simulation Collaboratory (ASC) portal. The ASC project provides a web-based problem solving framework for the astrophysics community that harnesses the capabilities of emerging computational grids.
Date: March 3, 2003
Creator: Bondarescu, Ruxandra; Allen, Gabrielle; Daues, Gregory; Kelly, Ian; Russell, Michael; Seidel, Edward et al.
System: The UNT Digital Library
Impact Analysis of Spent Fuel Dry Casks Under Accidental Drop Scenarios. (open access)

Impact Analysis of Spent Fuel Dry Casks Under Accidental Drop Scenarios.

A series of analyses were performed to assess the structural response of spent nuclear fuel dry casks subjected to various handling and on-site transfer events. The results of these analyses are being used by the Nuclear Regulatory Commission (NRC) to perform a probabilistic risk assessment (PRA). Although the PRA study is being performed for a specific nuclear plant, the PRA study is also intended to provide a framework for a general methodology that could also be applied to other dry cask systems at other nuclear plants. The dry cask system consists of a transfer cask, used for handling and moving the multi-purpose canister (MPC) that contains the fuel, and a storage cask, used to store the MPC and fuel on a concrete pad at the site. This paper describes the analyses of the casks for two loading events. The first loading consists of dropping the transfer cask while it is lowered by a crane to a concrete floor at ground elevation. The second loading consists of dropping the storage cask while it is being transferred to the concrete storage pad outdoors. Three dimensional finite element models of the transfer cask and storage cask, containing the MPC and fuel, were utilized …
Date: March 17, 2003
Creator: Braverman, J. I.; Morante, R. J.; Xu, J.; Hofmayer, C. H. & Shaukat, S. K.
System: The UNT Digital Library
Isotopic Tracing of Fuel Carbon in the Emissions of a Compression-Ignition Engine Fueled with Biodiesel Blends (open access)

Isotopic Tracing of Fuel Carbon in the Emissions of a Compression-Ignition Engine Fueled with Biodiesel Blends

Experimental tests were conducted on a Cummins 85.9 direct-injected diesel engine fueled with biodiesel blends. 20% and 50% blend levels were tested, as was 100% (neat) biodiesel. Emissions of particulate matter (PM), nitrogen oxides (NO{sub x}), hydrocarbons (HC) and CO were measured under steady-state operating conditions. The effect of biodiesel on PM emissions was mixed; however, the contribution of the volatile organic fraction to total PM was greater for the higher biodiesel blend levels. When only non-volatile PM mass was considered, reductions were observed for the biodiesel blends as well as for neat biodiesel. The biodiesel test fuels increased NO{sub x}, while HC and CO emissions were reduced. PM collected on quartz filters during the experimental runs were analyzed for carbon-14 content using accelerator mass spectrometry (AMs). These measurements revealed that carbon from the biodiesel portion of the blended fuel was marginally less likely to contribute to PM, compared to the carbon from the diesel portion of the fuel. The results are different than those obtained in previous tests with the oxygenate ethanol, which was observed to be far less likely contribute to PM than the diesel component of the blended fuel. The data suggests that chemical structure of the …
Date: March 3, 2003
Creator: Buchholz, B. A.; Cheng, A. S. & Dibble, R. W.
System: The UNT Digital Library
Status of the MINOS Experiment (open access)

Status of the MINOS Experiment

We report on the status of the MINOS long baseline neutrino experiment presently under construction at the Fermi National Accelerator Laboratory and the Soudan mine. There is growing evidence that the solar neutrino and atmospheric neutrino anomalies [1] are the result of neutrino oscillations. The MINOS experiment is a long baseline neutrino oscillation experiment designed to study the region of parameter space indicated by the SuperKamiokande atmospheric neutrino results [2]. The experiment consists of two detectors, one with a mass of 980 tons located at Fermilab (the near detector) and the other of mass 5400 tons located 731 km away in the Soudan mine in northern Minnesota (the far detector). The third component is the neutrino beam which is currently under construction at Fermilab.
Date: March 17, 2003
Creator: Buckley-Geer, Elizabeth
System: The UNT Digital Library
Biomonitoring with Wireless Communications (open access)

Biomonitoring with Wireless Communications

This review is divided into three sections: technologies for monitoring physiological parameters; biosensors for chemical assays and wireless communications technologies including image transmissions. Applications range from monitoring high risk patients for heart, respiratory activity and falls to sensing levels of physical activity in military, rescue, and sports personnel. The range of measurements include, heart rate, pulse wave form, respiratory rate, blood oxygen, tissue pCO2, exhaled carbon dioxide and physical activity. Other feasible measurements will employ miniature chemical laboratories on silicon or plastic chips. The measurements can be extended to clinical chemical assays ranging from common blood assays to protein or specialized protein measurements (e.g., troponin, creatine, and cytokines such as TNF and IL6). Though the feasibility of using wireless technology to communicate vital signs has been demonstrated 32 years ago (1) it has been only recently that practical and portable devices and communications net works have become generally available for inexpensive deployment of comfortable and affordable devices and systems.
Date: March 1, 2003
Creator: Budinger, Thomas F.
System: The UNT Digital Library
Laboratory Evaluation of an Electrochemical Noise System for Detection of Localized and General Corrosion of Natural Gas Transmission Pipelines (open access)

Laboratory Evaluation of an Electrochemical Noise System for Detection of Localized and General Corrosion of Natural Gas Transmission Pipelines

Gas transmission pipelines are susceptible to both internal (gas side) and external (soil side) corrosion attack. Internal corrosion is caused by the presence of salt laden moisture, CO{sub 2}, H{sub 2}S, and perhaps O{sub 2} in the natural gas. Internal corrosion usually manifests itself as general corrosion. However, the presence of chlorides in entrained water also can lead to pitting corrosion damage. The electrochemical noise technique can differentiate general from localized corrosion and provide estimates of corrosion rates without external perturbation of the corroding system. It is increasingly being applied to field and industrial installations for in situ corrosion monitoring. It has been used here to determine its suitability for monitoring internal and external corrosion damage on gas transmission pipelines. Corrosion measurements were made in three types of environments: (1) aqueous solutions typical of those found within gas pipelines in equilibrium with th e corrosive components of natural gas; (2) biologically-active soils typical of wetlands; and (3) a simulated, unpressurized, internal gas/liquid gas pipeline environment. Multiple sensor designs were evaluated in the simulated pipe environment. Gravimetric measurements were conducted in parallel with the electrochemical noise measurements to validate the results.
Date: March 16, 2003
Creator: Bullard, S. J.; Covino, B. S., Jr.; Russell, J. H.; Holcomb, G. R.; Cramer, S. D.; Ziomek-Moroz, M. et al.
System: The UNT Digital Library
Coalescence of Nanometer Silver Islands on Oxides Grown by Filtered Cathodic Arc Depostion (open access)

Coalescence of Nanometer Silver Islands on Oxides Grown by Filtered Cathodic Arc Depostion

This report talks about Coalescence of Nanometer Silver Islands on Oxides Grown by Filtered Cathodic Arc Depostion
Date: March 10, 2003
Creator: Byon, Eungsun; Oates, Thomas W.H. & Anders, Andre
System: The UNT Digital Library
Narrow linewidth intervalence-band emission from germanium THz lasers (open access)

Narrow linewidth intervalence-band emission from germanium THz lasers

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Date: March 24, 2003
Creator: Chamberlin, D.R.; Brundermann, E. & Haller, E.E.
System: The UNT Digital Library
Passive Seismic Monitoring for Rockfall at Yucca Mountain: Concept Tests (open access)

Passive Seismic Monitoring for Rockfall at Yucca Mountain: Concept Tests

For the purpose of proof-testing a system intended to remotely monitor rockfall inside a potential radioactive waste repository at Yucca Mountain, a system of seismic sub-arrays will be deployed and tested on the surface of the mountain. The goal is to identify and locate rockfall events remotely using automated data collecting and processing techniques. We install seismometers on the ground surface, generate seismic energy to simulate rockfall in underground space beneath the array, and interpret the surface response to discriminate and locate the event. Data will be analyzed using matched-field processing, a generalized beam forming method for localizing discrete signals. Software is being developed to facilitate the processing. To date, a three-component sub-array has been installed and successfully tested.
Date: March 3, 2003
Creator: Cheng, J.; Twilley, K.; Murvosh, H.; Tu, Y.; Luke, B.; Yfantis, A. et al.
System: The UNT Digital Library
Delamination Failure Investigation for Out-Of-Plane Loading in Laminates (open access)

Delamination Failure Investigation for Out-Of-Plane Loading in Laminates

In contrast to failure approaches at the lamina level or the micromechanics level the present work concerns failure characterization at the laminate level. Specifically, attention is given to the ultimate failure characterization for quasi-isotropic laminates. This is in further contrast to the commonly used approaches for initial damage or progressive damage. It is shown that the analytical failure forms decompose into two modes, one for out of plane, delamination type failure and one for in plane, fiber controlled type failure. The work here is mainly given over to the delamination mode of failure. Experimental results are presented for laminates in this mode of failure. These results are then integrated with the analytical forms to give a simple criterion for delamination failure.
Date: March 26, 2003
Creator: Christensen, R M & DeTeresa, S J
System: The UNT Digital Library
Role of Ash Deposits in the High Temperature Corrosion of Boiler Tubes (open access)

Role of Ash Deposits in the High Temperature Corrosion of Boiler Tubes

Ash deposits cause accelerated corrosion of waterwall boiler tubes in waste to energy (WTE) incinerators. To study this effect, a series of experiments were planned to determine the mechanism of corrosion of carbon steel boiler tubes under ash deposits. Results reported here were for carbon steel tubes exposed to an environment consisting of O{sub 2}, CO{sub 2}, N{sub 2}, and water vapor. Future experiments will include HCl and SO{sub 2}. Test procedures included both isothermal and thermal gradient tests. Temperatures ranged from 300 C to 510 C for the isothermal tests and a metal/gas temperature of 450/670 C for the thermal gradient test. Initial results indicated that increasing temperature caused the isothermal corrosion rates of ash-covered samples to increase. A shakedown test of a thermal gradient test apparatus was conducted at a metal/gas temperature of 450/670 C, a more severe environment than normally encountered in WTE waterwalls. Results showed that the corrosion rate under those conditions exceeds the isothermal corrosion rates at the same metal temperature by a factor of 2 or more.
Date: March 16, 2003
Creator: Covino, B. S., Jr.; Russell, J. H.; Cramer, S. D.; Holcomb, G. R.; Bullard, S. J.; Ziomek-Moroz, M. et al.
System: The UNT Digital Library
Atmospheric Transport of Radionuclides (open access)

Atmospheric Transport of Radionuclides

The purpose of atmospheric transport and diffusion calculations is to provide estimates of concentration and surface deposition from routine and accidental releases of pollutants to the atmosphere. This paper discusses this topic.
Date: March 3, 2003
Creator: Crawford, T. V.
System: The UNT Digital Library
Associated Higgs Boson Production With Heavy Quarks. (open access)

Associated Higgs Boson Production With Heavy Quarks.

The production of a Higgs boson in association with a pair of e quarks will play a very important role at both hadron and lepton colliders. We review the status of theoretical predictions and their relevance to Higgs boson studies, with particular emphasis on the recently calculated NLO QCD corrections to the inclusive cross section for p{bar p}, pp {yields} t{bar t}h. We conclude by briefly discussing the case of exclusive b{bar b}h production and the potential of this process in revealing signals of new physics beyond the Standard Model.
Date: March 15, 2003
Creator: Dawson, S.; Orr, L. H.; Reina, L. & Wackeroth, D.
System: The UNT Digital Library
Infiltration and Natural Ventilation Model for Whole-Building Energy Simulation of Residential Buildings: Preprint (open access)

Infiltration and Natural Ventilation Model for Whole-Building Energy Simulation of Residential Buildings: Preprint

The infiltration term in the building energy balance equation is one of the least understood and most difficult to model. For many residential buildings, which have an energy performance dominated by the envelope, it can be one of the most important terms. There are numerous airflow models; however, these are not combined with whole-building energy simulation programs that are in common use in North America. This paper describes a simple multizone nodal airflow model integrated with the SUNREL whole-building energy simulation program.
Date: March 1, 2003
Creator: Deru, M. & Burns, P.
System: The UNT Digital Library