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2004

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Articles 1 - 30 of 4199

Full-Text Articles in Physical Sciences and Mathematics

Emisja Chlorowodoru Ze Spalania Węgla W Kotle Pyłowym, Marian Mazur, Robert Oleniacz, Przemysław Szczygłowski, Marek Bogacki Dec 2004

Emisja Chlorowodoru Ze Spalania Węgla W Kotle Pyłowym, Marian Mazur, Robert Oleniacz, Przemysław Szczygłowski, Marek Bogacki

Robert Oleniacz

Emission of hydrogen chloride (HCl) from coal combustion is not controlled just like for example sulpfur dioxide emission. But HCl emission is also important, because chlorine content in some types of coal can reach the similar level to sulfur content. In the paper the measurement results of HCl emission to the air during combustion of three types of coal with law content of chlorine were presented. The researches were carried out for a steam pulverized coal boiler (max. boiler efficiency – 430 t/h) during three various loads (respectively 65, 80 and 95 % of maximum efficiency) without flue gas desulfurization. The ...


Theoretical Modeling Of Protective Oxide Layer Growth In Non-Isothermal Lead-Alloys Coolant Systems, Yitung Chen Dec 2004

Theoretical Modeling Of Protective Oxide Layer Growth In Non-Isothermal Lead-Alloys Coolant Systems, Yitung Chen

Transmutation Sciences Materials (TRP)

The goal of the proposed research project is to provide basic understanding of the protective oxide layer behaviors and to develop oxide layer growth models of steels in non-isothermal lead-alloys (lead or lead-bismuth eutectic) coolant systems. It is widely recognized that the corrosiveness of the lead-alloys is a critical obstacle and challenge for which it can be safely used or applied in the nuclear coolant systems. Active oxygen control technique can promote the formation of the “self-healing” oxide films on the structural material surface, drastically reducing steel corrosion and coolant contamination. Many experiments of steels exposed to flowing lead-alloys have ...


Development Of Dose Conversion Coefficients For Radionuclides Produced In Spallation Neutron Sources: Quarterly Progress Report 9/1/04 – 12/31/04, Phillip W. Patton, Mark Rudin Dec 2004

Development Of Dose Conversion Coefficients For Radionuclides Produced In Spallation Neutron Sources: Quarterly Progress Report 9/1/04 – 12/31/04, Phillip W. Patton, Mark Rudin

Transmutation Sciences Physics (TRP)

The research consortium comprised of representatives from several universities and national laboratories has successfully generated internal and external dose conversion coefficients for twenty radionuclides produced in spallation neutron sources. In addition, the group has identified twenty radionuclide that are missing electron capture files and eighteen additional radionuclides missing substantial physical data.


Evaluation Of Fluorapatite As A Waste-Form Material: First Quarter Report (2004-05), October 1 - December 31, 2004, Dennis W. Lindle, Oliver Hemmers Dec 2004

Evaluation Of Fluorapatite As A Waste-Form Material: First Quarter Report (2004-05), October 1 - December 31, 2004, Dennis W. Lindle, Oliver Hemmers

Separations Campaign (TRP)

Fluorapatite, fluorinated calcium phosphate, has been identified as a potential matrix for the entombment of the zirconium fluoride fission product waste stream from the proposed FLEX process. If the efficacy of fluorapatite-based waste-storage can be demonstrated, then new and potentially more-efficient options for handling and separating high-level wastes, based on fluoride-salt extraction, will become feasible. This proposal will develop a dual-path research project to develop a process to fabricate a synthetic fluorapatite waste form for the ZrF4, FP waste stream, characterize the waste form, examine its performance under environmental conditions, and correlate the behavior of the waste form with ...


Development Of Integrated Process Simulation System Model For Spent Fuel Treatment Facility (Sftf) Design: Quarterly Report October 1-December 31, 2004, Yitung Chen, Sean Hsieh Dec 2004

Development Of Integrated Process Simulation System Model For Spent Fuel Treatment Facility (Sftf) Design: Quarterly Report October 1-December 31, 2004, Yitung Chen, Sean Hsieh

Separations Campaign (TRP)

The Advanced Fuel Cycle Initiative (AFCI) and Transmutation Research Program- University Participation Program (TRP-UPP) supported by Department of Energy of the United States have been developing many important technologies for the transmutation of nuclear waste to address long-term disposal issues. While successfully embedding AMUSE module into a dedicated System Engineering Model (TRPSEMPro), developed by the Nevada Center for Advanced Computational Methods (NCACM) at the University of Nevada, Las Vegas collaborating with Argonne National Laboratory (ANL), ANL is interested in further simulating the Light Water Reactor (LWR) Spent Fuel Treatment Facility (SFTF) combining commercial process simulation and analysis packages and core ...


Cooperative Conservation - Interagency Volunteer Program Quarterly Progress Report: Period Ending December 31, 2004, Margaret N. Rees Dec 2004

Cooperative Conservation - Interagency Volunteer Program Quarterly Progress Report: Period Ending December 31, 2004, Margaret N. Rees

Get Outdoors Nevada

Collaboration with Interagency Team

During the third quarter, the interagency volunteer team and university representatives have held several meetings to continue progress on the Interagency Volunteer Program (IVP). At the beginning of October, candidates for the project manager position were interviewed by the university search committee, followed by interviews with the interagency team on October 6, 2004. After two finalists were identified, reference checks were made and the university and team recommended to the federal managers that Ms. Donna Grady be hired. Ms. Grady’s first day on the job was December 1, 2004. In the interim, Nancy Flagg, Public ...


Tidal Perturbations And Variability In Mesopause Region Over Fort Collins, Co(41n, 105w): Continuous Multi-Day Temperature And Wind Lidar Observations, C. Y. She, T. Li, R. L. Collins, Titus Yuan, B. P. Williams, T. Kawahara, J. D. Vance, P. Acott, D. A. Krueger, H. L. Liu, M. E. Hagan Dec 2004

Tidal Perturbations And Variability In Mesopause Region Over Fort Collins, Co(41n, 105w): Continuous Multi-Day Temperature And Wind Lidar Observations, C. Y. She, T. Li, R. L. Collins, Titus Yuan, B. P. Williams, T. Kawahara, J. D. Vance, P. Acott, D. A. Krueger, H. L. Liu, M. E. Hagan

All Physics Faculty Publications

An unusually long data set was acquired at the sodium lidar facility at Colorado State University (41N, 105W), between Sep 18 and Oct 01, 2003, including a 9-day continuous observation. This time is long enough to average out the perturbations of gravity waves and short-period planetary waves. As such, it can be used to define tidal-period perturbations in temperature and horizontal wind. Assuming the sodium mixing ratio is a constant of motion, the observed tidal-period oscillation in sodium density follows that of vertical wind. Thus, the data set defines tidal-period perturbations of temperature and wind vector. The observed amplitudes and ...


Minerva 2004, The Honors College Dec 2004

Minerva 2004, The Honors College

Minerva

This issue of Minerva includes an article on HON 350: An Introduction to Functional Genomics; an article on the creation and inaugural year of HON 180: A Cultural Odyssey; a profile on Honors alumnus, Charles Stanhope and his 2004 Distinguished Honors Graduate Lecture; and interviews with Allison Kelly, Jessica Hudec, and Jennifer Merchant on their experiences as Honors student-athletes.


Scaling A Dataflow Testing Methodology To The Multiparadigm World Of Commercial Spreadsheets, Marc Randall Fisher Ii, Gregg Rothermel, Tyler Creelan, Margaret Burnett Dec 2004

Scaling A Dataflow Testing Methodology To The Multiparadigm World Of Commercial Spreadsheets, Marc Randall Fisher Ii, Gregg Rothermel, Tyler Creelan, Margaret Burnett

CSE Technical reports

Spreadsheet languages are widely used by end users to perform a broad range of important tasks. Evidence shows, however, that spreadsheets often contain faults. Thus, in prior work we presented a dataflow testing methodology for use with spreadsheets, that provides feedback about the coverage of cells in spreadsheets via visual devices. Studies have shown that this methodology, which we call WYSIWYT (What You See Is What You Test), can be used cost-effectively by end-user programmers. To date, however, the methodology has been investigated across a limited set of spreadsheet language features. Commercial spreadsheet environments are multiparadigm languages, utilizing features often ...


Vortices In Bose-Einstein Condensates: Some Recent Developments, Panos Kevrekidis, R. Carretero-Gonzalez, D. Frantzeskakis, I. Kevrekidis Dec 2004

Vortices In Bose-Einstein Condensates: Some Recent Developments, Panos Kevrekidis, R. Carretero-Gonzalez, D. Frantzeskakis, I. Kevrekidis

Panos Kevrekidis

In this brief review we summarize a number of recent developments in the study of vortices in Bose-Einstein condensates, a topic of considerable theoretical and experimental interest in the past few years. We examine the generation of vortices by means of phase imprinting, as well as via dynamical instabilities. Their stability is subsequently examined in the presence of purely magnetic trapping, and in the combined presence of magnetic and optical trapping. We then study pairs of vortices and their interactions, illustrating a reduced description in terms of ordinary differential equations for the vortex centers. In the realm of two vortices ...


Transmission Of Neospora Caninum Between Wild And Domestic Animals, L.F.P. Gondim, M.M. Mcallister, N.E. Mateus-Pinilla, W.C. Pitt, L. D. Mech, M.E. Nelson Dec 2004

Transmission Of Neospora Caninum Between Wild And Domestic Animals, L.F.P. Gondim, M.M. Mcallister, N.E. Mateus-Pinilla, W.C. Pitt, L. D. Mech, M.E. Nelson

USDA National Wildlife Research Center - Staff Publications

To determine whether deer can transmit Neospora caninum, brains of naturally infected white-tailed deer (Odocoileus virginianus) were fed to 4 dogs; 2 of these dogs shed oocysts. Oocysts from 1 of the dogs were tested by polymerase chain reaction and found to be positive for N. caninum and negative for Hammondia heydorni. The internal transcribed spacer 1 sequence of the new strain (designated NC-deer1) was identical to N. caninum from domestic animals, indicating that N. caninum is transmitted between wild and domestic animals, often enough to prevent divergent evolution of isolated populations of the parasite. NC-deer1 oocysts were administered ...


Analysis Of Oligonucleotide Array Experiments With Repeated Measures Using Mixed Models, Hao Li, Constance L. Wood, Thomas V. Getchell, Marilyn L. Getchell, Arnold J. Stromberg Dec 2004

Analysis Of Oligonucleotide Array Experiments With Repeated Measures Using Mixed Models, Hao Li, Constance L. Wood, Thomas V. Getchell, Marilyn L. Getchell, Arnold J. Stromberg

Statistics Faculty Publications

BACKGROUND: Two or more factor mixed factorial experiments are becoming increasingly common in microarray data analysis. In this case study, the two factors are presence (Patients with Alzheimer's disease) or absence (Control) of the disease, and brain regions including olfactory bulb (OB) or cerebellum (CER). In the design considered in this manuscript, OB and CER are repeated measurements from the same subject and, hence, are correlated. It is critical to identify sources of variability in the analysis of oligonucleotide array experiments with repeated measures and correlations among data points have to be considered. In addition, multiple testing problems are ...


Influence Of Hydraulic Property Correlation On Predicted Dense Nonaqueous Phase Liquid Source Zone Architecture, Mass Recovery And Contaminant Flux, Lawrence D. Lemke, Linda M. Abriola, John R. Lang Dec 2004

Influence Of Hydraulic Property Correlation On Predicted Dense Nonaqueous Phase Liquid Source Zone Architecture, Mass Recovery And Contaminant Flux, Lawrence D. Lemke, Linda M. Abriola, John R. Lang

Geology Faculty Research Publications

Organic liquid saturation distributions resulting from a simulated tetrachloroethene (PCE) spill were generated with alternative models of spatially varying aquifer properties for a statistically homogeneous, nonuniform sand aquifer. The distributions were analyzed to quantify DNAPL source zone characteristics and then incorporated as initial conditions for simulated PCE recovery using surfactant-enhanced aquifer remediation (SEAR). The predicted evolution of the spatial distribution of DNAPL saturations or source zone ‘‘architectures’’ and associated remediation efficiencies are strongly influenced by the spatial correlation of aquifer parameters and multiphase flow constitutive relationships. Model predictions suggest that removal of 60 to 99% of entrapped PCE can reduce ...


The Icdm Development Toolkit: Technical Description, Russell Leighton, Lakshmi Vempati, Alan Davis, Mark Porczak, Jens G. Pohl Dec 2004

The Icdm Development Toolkit: Technical Description, Russell Leighton, Lakshmi Vempati, Alan Davis, Mark Porczak, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

This report provides a technical description of the Integrated Cooperative Decision-Making (ICDM) software toolkit for the development of intelligent decision-support applications. An overview of the transformational forces that have precipitated the need for a development toolkit capable of supporting a distributed, information-centric software environment, and the objectives of ICDM are contained in a companion CDM Technical Report (CDM-16-04) entitled: “The ICDM Development Toolkit: Purpose and Overview”.

ICDM is an application development framework and toolkit for distributed decision-support systems incorporating software agents that collaborate with each other and human users to monitor changes (i.e., events) in the state of problem ...


Cofactor Fingerprinting With Std Nmr To Characterize Proteins Of Unknown Function: Identification Of A Rare Ccmp Cofactor Preference, Huili Yao, Daniel Sem Dec 2004

Cofactor Fingerprinting With Std Nmr To Characterize Proteins Of Unknown Function: Identification Of A Rare Ccmp Cofactor Preference, Huili Yao, Daniel Sem

Chemistry Faculty Research and Publications

Proteomics efforts have created a need for better strategies to functionally categorize newly discovered proteins. To this end, we have employed saturation transfer difference NMR with pools of closely related cofactors, to determine cofactor preferences. This approach works well for dehydrogenases and has also been applied to cyclic nucleotide‐binding proteins. In the latter application, a protein (radial spoke protein‐2, RSP2) that plays a central role in forming the radial spoke of Chlamydomonas reinhardtii flagella was shown to bind cCMP. cCMP‐binding proteins are rare, although previous reports of their presence in sperm and flagella suggest that cCMP may ...


Evidence For Correlated Titanium And Deuterium Depletion In The Galactic Ism, Jason X. Prochaska, Todd M. Tripp, Christopher Howk Dec 2004

Evidence For Correlated Titanium And Deuterium Depletion In The Galactic Ism, Jason X. Prochaska, Todd M. Tripp, Christopher Howk

Astronomy Department Faculty Publication Series

Current measurements indicate that the deuterium abundance in diffuse interstellar gas varies spatially by a factor of ~4 among sightlines extending beyond the Local Bubble. One plausible explanation for the scatter is the variable depletion of D onto dust grains. To test this scenario, we have obtained high signal-to-noise, high resolution profiles of the refractory ion Ti II along seven Galactic sightlines with D/H ranging from 0.65 to 2.1 × 10−5. These measurements, acquired with the recently upgraded Keck/HIRES spectrometer, indicate a correlation between Ti/H and D/H at the > 95% c.l. Therefore, our ...


Evidence For Correlated Titanium And Deuterium Depletion In The Galactic Ism, Jason X. Prochaska, Todd M. Tripp, Christopher Howk Dec 2004

Evidence For Correlated Titanium And Deuterium Depletion In The Galactic Ism, Jason X. Prochaska, Todd M. Tripp, Christopher Howk

Todd M. Tripp

Current measurements indicate that the deuterium abundance in diffuse interstellar gas varies spatially by a factor of ~4 among sightlines extending beyond the Local Bubble. One plausible explanation for the scatter is the variable depletion of D onto dust grains. To test this scenario, we have obtained high signal-to-noise, high resolution profiles of the refractory ion Ti II along seven Galactic sightlines with D/H ranging from 0.65 to 2.1 × 10−5. These measurements, acquired with the recently upgraded Keck/HIRES spectrometer, indicate a correlation between Ti/H and D/H at the > 95% c.l. Therefore, our ...


Leptonic Cp Violation In A Two Parameter Model, Joseph Schechter, Samina S. Masood, Salah Nasri Dec 2004

Leptonic Cp Violation In A Two Parameter Model, Joseph Schechter, Samina S. Masood, Salah Nasri

Physics

We further study the "complementary" Ansatz, Tr(M_\nu)=0, for a prediagonal light Majorana type neutrino mass matrix. Previously, this was studied for the CP conserving case and the case where the two Majorana type CP violating phases were present but the Dirac type CP violating phase was neglected. Here we employ a simple geometric algorithm which enables us to "solve" the Ansatz including all three CP violating phases. Specifically, given the known neutrino oscillation data and an assumed two parameter (the third neutrino mass m_3 and the Dirac CP phase \delta) family of inputs we predict the neutrino ...


Snow Accumulation, Surface Height Change, And Firn Densification At Summit, Greenland: Insights From 2 Years Of In Situ Observation, Jack E. Dibb, Mark Fahnestock Dec 2004

Snow Accumulation, Surface Height Change, And Firn Densification At Summit, Greenland: Insights From 2 Years Of In Situ Observation, Jack E. Dibb, Mark Fahnestock

Earth Sciences Scholarship

Weekly measurements of surface height change were made at an accumulation forest of 100 stakes at Summit, Greenland, over a 2-year period (17 August 2000 to 8 August 2002). On average, the surface height relative to the stakes increased 64 (±4.8) cm in the first year and 65 (±5.3) cm in the second, identical to the average (65 ± 4.5 cm yr−1) previously reported for the period 1991–1995 in a similar forest 28 km to the southwest. The continuous 2-year data set indicates that the rate of surface rise was not constant, with the summers of ...


Summertime Ozone At Mount Washington: Meteorological Controls At The Highest Peak In The Northeast, E V. Fischer, R. Talbot, Jack E. Dibb Dec 2004

Summertime Ozone At Mount Washington: Meteorological Controls At The Highest Peak In The Northeast, E V. Fischer, R. Talbot, Jack E. Dibb

Earth Sciences Scholarship

This study examined the synoptic and regional-scale meteorological controls on summertime O3 at Mount Washington, the highest peak (1910 m) in the northeastern United States. Analysis of air mass transport to Mount Washington was conducted for the summers of 1998–2003 using backward trajectories. Distinct patterns in air mass history were revealed using this approach that helped explain extreme variations in O3 mixing ratios. Most enhanced (≥90th percentile) and depleted (≤10th percentile) O3 events were short-lived and spread out over the summer months. Enhanced O3 events at Mount Washington were generally associated with westerly transport, while ...


Pseudorapidity Asymmetry And Centrality Dependence Of Charged Hadron Spectra In D+Au Collisions At √SNn=200 Gev, Star Collaboration, T.D. Gutierrez Dec 2004

Pseudorapidity Asymmetry And Centrality Dependence Of Charged Hadron Spectra In D+Au Collisions At √SNn=200 Gev, Star Collaboration, T.D. Gutierrez

Physics

The pseudorapidity asymmetry and centrality dependence of charged hadron spectra in d+Au collisions at √sNN=200 GeV are presented. The charged particle density at midrapidity, its pseudorapidity asymmetry, and centrality dependence are reasonably reproduced by a multiphase transport model, by HIJING, and by the latest calculations in a saturation model. Ratios of transverse momentum spectra between backward and forward pseudorapidity are above unity for pT below 5GeV ∕ c. The ratio of central to peripheral spectra in d+Au collisions shows enhancement at 2 < pT < 6GeV ∕ c, with a larger effect at backward rapidity than forward rapidity. Our measurements are in qualitative agreement with gluon saturation and in contrast to calculations based on incoherent multiple partonic scatterings.


Structure And Properties Of High Stability Geminal Dicationic Ionic Liquids, Jared L. Anderson, Rongfang Ding, Arkady Ellern, Daniel W. Armstrong Dec 2004

Structure And Properties Of High Stability Geminal Dicationic Ionic Liquids, Jared L. Anderson, Rongfang Ding, Arkady Ellern, Daniel W. Armstrong

Chemistry Publications

Thirty-nine geminal dicationic ILs were synthesized and characterized in terms of their surface tensions, densities, melting points, refractive indices, viscosities, and miscibilities with a polar and nonpolar solvent. Two imidazolium or pyrrolidinium cations were joined via different length hydrocarbon linkage chains (from 3 to 12 carbons long). The various geminal dications were paired with up to four different anions. The effect of the dication type, linkage chain, alkyl substituents, and anion type on the physicochemical properties of these compounds was examined. Among the more interesting findings for this class of compounds was that their liquid and thermal stability ranges generally ...


Advisory Circular: Reporting Wildlife Aircraft Strikes, J.R. White Dec 2004

Advisory Circular: Reporting Wildlife Aircraft Strikes, J.R. White

Other Bird Strike and Aviation Materials

This Advisory Circular (AC) explains the importance of reporting collisions between aircraft and wildlife, more commonly referred to as wildlife strikes. It also examines recent improvements in the Federal Aviation Administration’s (FAA) Bird/Other Wildlife Strike Reporting system; how to report a wildlife strike; what happens to the wildlife strike report data; how to access the FAA National Wildlife Aircraft Strike Database; and the FAA’s Feather Identification program.


Use Of Chiral Ionic Liquids As Solvents For The Enantioselective Photoisomerization Of Dibenzobicyclo[2.2.2]Octatrienes, Jie Ding, Vasumathi Desikan, Xinxin Han, Tom L. Xiao, Rongfang Ding, William S. Jenks, Daniel W. Armstrong Dec 2004

Use Of Chiral Ionic Liquids As Solvents For The Enantioselective Photoisomerization Of Dibenzobicyclo[2.2.2]Octatrienes, Jie Ding, Vasumathi Desikan, Xinxin Han, Tom L. Xiao, Rongfang Ding, William S. Jenks, Daniel W. Armstrong

Chemistry Publications

Six chiral ionic liquids were prepared and evaluated as “chiral induction solvents” in which two different dibenzobicyclo[2.2.2]octatrienes were photoisomerized to chiral products. Enantiomeric excesses from 3 to 12% were obtained from the photochemical di-π-methane rearrangement. Results indicate that the chiral induction derives from an ion pairing interaction of the deprotonated diacids with the ionic liquid cation. This is the first report on chiral induction via a chiral IL for an irreversible, unimolecular photochemical isomerization.


Driven By Data, Larry Bedgood Dec 2004

Driven By Data, Larry Bedgood

Lesson Plans

Students should enjoy the experience of creating/designing their forms on the computer using WORD and EXCEL software. Students will use calculators at first to sum and find statistics, and later use EXEL and should be able to conclude it was easier to use EXCEL because or the additional reporting opportunities. Students will be exposed to work in STELLA.


Computer Simulations Of Ions, Dipoles, Dna Elasticity And Interfaces, Jayendran Rasaiah Dec 2004

Computer Simulations Of Ions, Dipoles, Dna Elasticity And Interfaces, Jayendran Rasaiah

University of Maine Office of Research Administration: Grant Reports

Jay Rasaiah of the University of Maine is supported by a grant from the Theoretical and Computational Chemistry Program to continue his research on condensed phase fluid systems. Proposed research focuses on four topics: 1) ionic mobility and association, water structure and dynamics in supercritical solutions; 2) phase transitions of polar fluids; 3) intrinsic elasticity of DNA; and 4) structure and dynamics of water and ions in contact with hydrophobic surfaces and electrodes. Rasaiah will use a combination of molecular simulations and formal theory to attack these problems. Computer simulations involving water will use an extended SPC/E model that ...


Partitioning Regular Polygons Into Circular Pieces Ii: Nonconvex Partitions, Mirela Damian, Joseph O'Rourke Dec 2004

Partitioning Regular Polygons Into Circular Pieces Ii: Nonconvex Partitions, Mirela Damian, Joseph O'Rourke

Computer Science: Faculty Publications

We explore optimal circular nonconvex partitions of regular k-gons. The circularity of a polygon is measured by its aspect ratio: the ratio of the radii of the smallest circumscribing circle to the largest inscribed disk. An optimal circular partition minimizes the maximum ratio over all pieces in the partition. We show that the equilateral triangle has an optimal 4-piece nonconvex partition, the square an optimal 13-piece nonconvex partition, and the pentagon has an optimal nonconvex partition with more than 20 thousand pieces. For hexagons and beyond, we provide a general algorithm that approaches optimality, but does not achieve it.


Fixed-Connectivity Membranes, Mark Bowick Dec 2004

Fixed-Connectivity Membranes, Mark Bowick

Physics

The statistical mechanics of flexible surfaces with internal elasticity and shape fluctuations is summarized. Phantom and self-avoiding isotropic and anisotropic membranes are discussed, with emphasis on the universal negative Poisson ratio common to the low-temperature phase of phantom membranes and all strictly self-avoiding membranes in the absence of attractive interactions. The study of crystalline order on the frozen surface of spherical membranes is also treated.


Secure Context-Sensitive Authorization, Kazuhiro Minami, David Kotz Dec 2004

Secure Context-Sensitive Authorization, Kazuhiro Minami, David Kotz

Open Dartmouth: Peer-reviewed articles by Dartmouth faculty

There is a recent trend toward rule-based authorization systems to achieve flexible security policies. Also, new sensing technologies in pervasive computing make it possible to define context-sensitive rules, such as “allow database access only to staff who are currently located in the main office.” However, these rules, or the facts that are needed to verify authority, often involve sensitive context information. This paper presents a secure context-sensitive authorization system that protects confidential information in facts or rules. Furthermore, our system allows multiple hosts in a distributed environment to perform the evaluation of an authorization query in a collaborative way; we ...


Structural Properties Of Discs And Bulges Of Early-Type Galaxies, Roelof S. De Jong, Luc Simard, Roger L. Davies, R. P. Saglia, David Burstein, Matthew Colless, Robert Mcmahan, Gary Wegner Dec 2004

Structural Properties Of Discs And Bulges Of Early-Type Galaxies, Roelof S. De Jong, Luc Simard, Roger L. Davies, R. P. Saglia, David Burstein, Matthew Colless, Robert Mcmahan, Gary Wegner

Open Dartmouth: Peer-reviewed articles by Dartmouth faculty

We have used the EFAR sample of galaxies to investigate the light distributions of early-type galaxies. We decompose the two-dimensional light distribution of the galaxies in a flattened spheroidal component with a Sérsic radial light profile and an inclined disc component with an exponential light profile. We show that if we assume that all galaxies can have a spheroidal and a disc component, then the brightest, bulge-dominated elliptical galaxies have a fairly broad distribution in the Sérsic profile shape parameter nB, with a median of approximately 3.7 and with σ∼ 0.9. Other galaxies have smaller nB ...