From Crisis to Transition: The State of Russian Science Based on Focus Groups with Nuclear Physicists (open access)

From Crisis to Transition: The State of Russian Science Based on Focus Groups with Nuclear Physicists

The collapse of the Soviet system led to a sharp contraction of state funding for science. Formerly privileged scientists suddenly confronted miserly salaries (often paid late), plummeting social prestige, deteriorating research facilities and equipment, and few prospects for improvement. Many departed the field of science for more lucrative opportunities, both within Russia and abroad. The number of inventions, patent applications, and publications by Russian scientists declined. Reports of desperate nuclear physicists seeking work as tram operators and conducting hunger strikes dramatized the rapid collapse of one of the contemporary world's most successful scientific establishments. Even more alarming was the 1996 suicide of Vladimir Nechai, director of the second largest nuclear research center in Russia (Chelyabinsk-70, now known as Snezhinsk). Nechai, a respected theoretical physicist who spent almost 40 years working on Soviet and Russian nuclear programs, killed himself because he could no longer endure his inability to rectify a situation in which his employees had not been paid for more than 5 months and were ''close to starvation.'' The travails of Russia's scientists sparked interest in the West primarily because of the security threat posed by their situation. The seemingly relentless crisis in science raised fears that disgruntled scientists might …
Date: December 9, 2001
Creator: Gerber, T P & Ball, D Y
Object Type: Article
System: The UNT Digital Library
Metallization of Hydrogen and Other Small Molecules at 100 GPa Pressures (open access)

Metallization of Hydrogen and Other Small Molecules at 100 GPa Pressures

Fluid hydrogen, oxygen, and nitrogen become metallic at 100 GPa (1 Mbar) pressures. Disorder is the primary reason for observing a metal at lower pressures in the fluid than expected for the ordered solid. This metallic transition is similar to those observed in fluid Cs and Rb by Hensel et al. All five undergo a Mott transition from a semiconducting to metallic fluid with the same electrical conductivities. In contrast, water is a proton conductor at pressures up to 200 GPa. Extreme conditions were achieved for {approx}100 ns with a reverberating shock wave generated with a two-stage light-gas gun.
Date: August 17, 2001
Creator: Nellis, W J
Object Type: Article
System: The UNT Digital Library
First Field Trial of Optical Label-Based Switching and Packet Drop on a 477km NTON/Sprint Link (open access)

First Field Trial of Optical Label-Based Switching and Packet Drop on a 477km NTON/Sprint Link

We demonstrate the first field trial of optical label-based wavelength switching and packet drop on 476.8km of the National Transparent Optical Network. Subcarrier multiplexed labels control a switch fabric that includes a tunable wavelength converter and arrayed waveguide grating router.
Date: December 10, 2001
Creator: Hernandez, V. J.; Pan, Z.; Cao, J.; Tsui, V. K.; Bansal, Y.; Fong, S. K. H. et al.
Object Type: Article
System: The UNT Digital Library
Why are the P{sub n} and S{sub n} Methods Equivalent (open access)

Why are the P{sub n} and S{sub n} Methods Equivalent

The author assumes that the reader is familiar with the Spherical harmonics, Pn, method and the discrete ordinates, S{sub n}, method; for a derivation of the equations used in these methods. I will only discuss the Boltzmann equation in one dimension, and the Sn method using Gaussian quadrature. I will do this merely to simplify the following discussion; once you understand the concepts presented here you can easily extend the conclusions to more general situations. Why are the spherical harmonics P{sub n} and discrete ordinate S{sub n} methods, or more correctly the P{sub n} and S{sub n+1} methods, equivalent, e.g., P{sub 3} is equivalent to S{sub 4}? When the S{sub n} method uses a Gaussian quadrature most textbooks will tell you that both methods are equivalent to assuming that the angular flux can be represented by a Legendre polynomial expansion of order n. Most textbooks are wrong [1]. We know that the S{sub n} method constrains the ''particles'' to travel in discrete directions; when Gaussian quadrature is used these discrete directions correspond to the zeros of the Legendre polynomial P{sub n+1}({mu}). What is not immediately obvious is that the P{sub n} method constrains the ''particles'' in exactly the same way. …
Date: September 19, 2001
Creator: Cullen, D E
Object Type: Report
System: The UNT Digital Library
Gas Pressure Forming of Titanium Alloys and Composites by Transformation Superplasticity (open access)

Gas Pressure Forming of Titanium Alloys and Composites by Transformation Superplasticity

By thermally cycling through their transformation temperature range, coarse-grained, polymorphic materials can be deformed superplastically, owing to the emergence of transformation mismatch plasticity (or transformation superplasticity) as a deformation mechanism. This mechanism is investigated under biaxial stress conditions during thermal cycling of unalloyed titanium, Ti-6Al-4V, and their composites (Ti/10 vol.% TiC{sub p}, Ti-6Al-4V/10 vol% TiC{sub p} and Ti-6Al-4V/5 vol.% TiB{sub w}). During gas-pressure dome bulging experiments, the dome height was measured as a function of forming time. Adapting existing models of biaxial doming to the case of transformation superplasticity where the strain-rate sensitivity is unity, we verify the operation of this deformation mechanism in all experimental materials, and compare the biaxial results to uniaxial thermal cycling results on the same materials. Finally, existing thickness distribution models are compared with experimentally measured profiles.
Date: October 23, 2001
Creator: Frary, M; Schuh, C & Dunand, D C
Object Type: Article
System: The UNT Digital Library
The BOUT Project: Validation and Benchmark of BOUT Code and Experimental Diagnostic Tools for Fusion Boundary Turbulence (open access)

The BOUT Project: Validation and Benchmark of BOUT Code and Experimental Diagnostic Tools for Fusion Boundary Turbulence

A boundary plasma turbulence code BOUT is presented. The preliminary encouraging results have been obtained when comparing with probe measurements for a typical Ohmic discharge in CT-7 tokamak. The validation and benchmark of BOUT code and experimental diagnostic tools for fusion boundary plasma turbulence is proposed.
Date: August 9, 2001
Creator: Xu, X Q
Object Type: Article
System: The UNT Digital Library
Measurement of Low Level Explosives Reaction in Gauged Multi-Dimensional Steven Impact Tests (open access)

Measurement of Low Level Explosives Reaction in Gauged Multi-Dimensional Steven Impact Tests

The Steven Test was developed to determine relative impact sensitivity of metal encased solid high explosives and also be amenable to two-dimensional modeling. Low level reaction thresholds occur at impact velocities below those required for shock initiation. To assist in understanding this test, multi-dimensional gauge techniques utilizing carbon foil and carbon resistor gauges were used to measure pressure and event times. Carbon resistor gauges indicated late time low level reactions 200-540 {micro}s after projectile impact, creating 0.39-2.00 kb peak shocks centered in PBX 9501 explosives discs and a 0.60 kb peak shock in a LX-04 disk. Steven Test modeling results, based on ignition and growth criteria, are presented for two PBX 9501 scenarios: one with projectile impact velocity just under threshold (51 m/s) and one with projectile impact velocity just over threshold (55 m/s). Modeling results are presented and compared to experimental data.
Date: May 31, 2001
Creator: Niles, A M; Garcia, F; Greenwood, D W; Forbes, J W; Tarver, C M; Chidester, S K et al.
Object Type: Article
System: The UNT Digital Library
Effects of pressure and saturation on seismic velocities and impedance measurements (open access)

Effects of pressure and saturation on seismic velocities and impedance measurements

Two synthetic data sets were examined to study the possible methods for distinguishing the effects of changes in saturation, and changes in pore pressure, on seismic velocity and impedance measurements. The results show that the results obtained previously on the dependence of laboratory velocity data on changes in saturation carry over without change to the data in these data sets. The assumption in this case is that the only data available are the seismic velocities. This situation can arise in cross-well seismic tomography. Of more direct interest to this project is how these methods and results should change when the data are instead seismic impedance measurements. The main conclusions are that the most appropriate plotting methods for seismic impedance data in order to distinguish changes in saturation, changes in pressure, and saturation changes from pressure changes are ({rho}{mu}, {lambda}/{mu}) and ({mu}/{lambda}, {rho}{mu}{sup 2}/{lambda}). All of these plotting coordinates can be computed easily from the impedance data {rho}{nu}{sub p} and {rho}{nu}{sub s}, since {rho}{mu} = ({rho}{nu}{sub s}){sup 2}, and {rho}{lambda} = ({rho}{nu}{sub p}){sup 2} - 2({rho}{nu}{sub s}){sup 2}, while {lambda}/{mu} = {rho}{lambda}/{rho}{mu} and {rho}{mu}{sup 2}/{lambda} = ({rho}{mu}){sup 2}/{rho}{lambda}. These choices are not the only possibilities, but they seem to give the …
Date: January 18, 2001
Creator: Berryman, James G.
Object Type: Report
System: The UNT Digital Library
Development of Lower Energy Neutron Spectroscopy for Areal Density Measurement in Implosion Experiment at NIF and Omega (open access)

Development of Lower Energy Neutron Spectroscopy for Areal Density Measurement in Implosion Experiment at NIF and Omega

Areal density ({rho}R) is a fundamental parameter that characterizes the performance of an ICF implosion. For high areal densities ({rho}R> 0.1 g/cm{sup 2}), which will be realized in implosion experiments at NIF and LMJ, the target areal density exceeds the stopping range of charged particles and measurements with charged particle spectroscopy will be difficult. In this region, an areal density measurement method using down shifted neutron counting is a promising alternative. The probability of neutron scattering in the imploded plasma is proportional to the areal density of the plasma. The spectrum of neutrons scattered by the specific target nucleus has a characteristic low energy cut off. This enables separate, simultaneous measurements of fuel and pusher {rho}Rs. To apply this concept in implosion experiments, the detector should have extremely large dynamic range. Sufficient signal output for low energy neutrons is also required. A lithium-glass scintillation-fiber plate (LG-SCIFI) is a promising candidate for this application. In this paper we propose a novel technique based on downshifted neutron measurements with a lithium-glass scintillation-fiber plate. The details of instrumentation and background estimation with Monte Carlo calculation are reported.
Date: August 2, 2001
Creator: Isumi, N; Lerche, R A; Phillips, T W; Schmid, G J; Moran, M J & Sangster, T C
Object Type: Article
System: The UNT Digital Library
H2O Outgassing In and Its Effects on M9787 Silicone (open access)

H2O Outgassing In and Its Effects on M9787 Silicone

Temperature programmed desorption (TPD) was performed on M9787 silicone, Cab-O-Sil-M-7D (fumed) and Hi-Sil-233 (precipitated) silica particles that had been annealed to 460 K for 24 hours then exposed to different moisture levels. Our results suggest that moisture desorption and adsorption in M9787 can be approximated by the interaction of its silica contents (Cab-O-Sil-M-7D and Hi-Sil-233) with moisture. Our experimental data also reveal that, in general, as heat treated silica particles are exposed to moisture, chemisorbed states, then physisorbed states are gradually filled up in that order. However, there seems to have some rearrangement of bonds as moisture desorbs or absorbs on the surfaces of the silica particles. Nanoindentation was also performed on M9787 silicones that were simultaneously pumped down to a few hundred Pa of residual pressure at room temperature. Our data shows that the removal of physisorbed water in M9787 has none or reversible little effect on the mechanical properties of M9787.
Date: September 1, 2001
Creator: Dinh, L N; Schildbach, M A; McLean, W; Balazs, B; LeMay, J D & Balooch, M
Object Type: Report
System: The UNT Digital Library
Accounting Data to Web Interface Using PERL (open access)

Accounting Data to Web Interface Using PERL

This document will explain the process to create a web interface for the accounting information generated by the High Performance Storage Systems (HPSS) accounting report feature. The accounting report contains useful data but it is not easily accessed in a meaningful way. The accounting report is the only way to see summarized storage usage information. The first step is to take the accounting data, make it meaningful and store the modified data in persistent databases. The second step is to generate the various user interfaces, HTML pages, that will be used to access the data. The third step is to transfer all required files to the web server. The web pages pass parameters to Common Gateway Interface (CGI) scripts that generate dynamic web pages and graphs. The end result is a web page with specific information presented in text with or without graphs. The accounting report has a specific format that allows the use of regular expressions to verify if a line is storage data. Each storage data line is stored in a detailed database file with a name that includes the run date. The detailed database is used to create a summarized database file that also uses run date …
Date: August 13, 2001
Creator: Hargeaves, C
Object Type: Report
System: The UNT Digital Library
Measurement of Ultra Low Outgassing Rates for NLC UHV Vacuum Chambers (open access)

Measurement of Ultra Low Outgassing Rates for NLC UHV Vacuum Chambers

Ultra low outgassing rates would be highly advantageous in accelerators and storage rings, such as the Next Linear Collider (NLC), where an outgassing rate of <10{sup -12} Torr liter/sec/cm{sup 2} could eliminate the need for costly distributed pumping. Measuring such low outgassing rates at room temperature has many difficulties. However, by inspection of Fick's law, it can be seen that thermal desorption is proportional to outgassing rate. It is commonly observed that the outgas rate doubles approximately every 15 C for temperatures under 100 C. By measuring outgassing rate versus temperature and time and extrapolating back to room temperature we can measure outgassing rates that would otherwise be difficult to make. To produce a reliable measurement also requires the total surface area under study to be approximately an order of magnitude greater than the area of the measurement chamber walls. To accomplish this, 27 plates of 5083 aluminum were placed in the measurement chamber. This technique will be the basis for future investigation of outgassing rates of other sample plates fabricated with different machining and cleaning techniques.
Date: June 12, 2001
Creator: Kishiyama, K.; Shen, S.; Behne, D.; Corlett, J. N.; Atkinson, D.; Kennedy, K. et al.
Object Type: Article
System: The UNT Digital Library
Modeling of Building Scale Flow and Dispersion (open access)

Modeling of Building Scale Flow and Dispersion

Predictions of airflows around buildings and the associated thermal and dispersion phenomena continue to be challenging because of the presence of extremely heterogeneous surface structures within urban areas. Atmospheric conditions can induce local winds to flow around structures rather than over them. Thus pollutants that are released at or near the ground tend to persist at relatively low levels with only minimal ventilation of the airborne material away from the ground surface. While flow and dispersion phenomena can be studied within wind tunnel settings, recent advances in numerical modeling have enabled computational fluid dynamics (CFD) to evolve into an important tool in the simulation of building scale flows. They are developing numerical models to simulate the flow and dispersion of releases around multi-building complexes. These models will be used to assess the transport and fate of releases of hazardous agents within urban areas and to support emergency response activities. There are already a number of models that have been developed to simulate flow and dispersion around urban settings. A recent collection of these papers can be found in the Proceedings of the International Workshop on CFD for Wind Climate in Cities. Most of the simulation studies presented in the literature …
Date: July 10, 2001
Creator: Lee, R L; Calhoun, R J; Chan, S T; Leone, J & Stevens, D E
Object Type: Article
System: The UNT Digital Library
Multi-Scale Thermohydrologic Model Sensitivity-Study Calculations in Support of the SSPA (open access)

Multi-Scale Thermohydrologic Model Sensitivity-Study Calculations in Support of the SSPA

The purpose of this calculation report is to document the thermohydrologic (TH) model calculations performed for the Supplemental Science and Performance Analysis (SSPA), Volume 1, Section 5 and Volume 2 (BSC 2001d [DIRS 155950], BSC 2001e [DIRS 154659]). The calculations are documented here in accordance with AP-3.12Q REV0 ICN4 [DIRS 154418]. The Technical Working Plan (Twp) for this document is TWP-NGRM-MD-000015 Real. These TH calculations were primarily conducted using three model types: (1) the Multiscale Thermohydrologic (MSTH) model, (2) the line-averaged-heat-source, drift-scale thermohydrologic (LDTH) model, and (3) the discrete-heat-source, drift-scale thermal (DDT) model. These TH-model calculations were conducted to improve the implementation of the scientific conceptual model, quantify previously unquantified uncertainties, and evaluate how a lower-temperature operating mode (LTOM) would affect the in-drift TH environment. Simulations for the higher-temperature operating mode (HTOM), which is similar to the base case analyzed for the Total System Performance Assessment for the Site Recommendation (TSPA-SR) (CRWMS M&O 2000j [DIRS 153246]), were also conducted for comparison with the LTOM. This Calculation Report describes (1) the improvements to the MSTH model that were implemented to reduce model uncertainty and to facilitate model validation, and (2) the sensitivity analyses conducted to better understand the influence of parameter …
Date: December 20, 2001
Creator: Glascoe, L G; Buscheck, T A; Loosmore, G A & Sun, Y
Object Type: Report
System: The UNT Digital Library
Cooperative MPC&A Enhancements at Russian Navy Sites (open access)

Cooperative MPC&A Enhancements at Russian Navy Sites

U.S. MPC&A cooperation with the Russian Federation (RF) Navy is based on a Joint Statement signed in 1996 to protect Highly Enriched Uranium (HEU) fresh fuel used for nuclear propulsion. The Russian Federation Navy is the largest owner in Russia of highly enriched uranium, both in the form of fresh nuclear fuel, and in the form of slightly irradiated fuel with a long cooling time after irradiation. As a result of this agreement, projects began at the Northern Fleet Fresh Fuel Storage Facility (Site 49) and Refueling Ship PM-63. Initial projects provided upgrades for RF Navy HEU fresh fuel storage facilities, beginning with a land-based facility near Murmansk and later adding other land-based and ship-based fresh fuel storage facilities. Additional protocols (December 1997, January 1999, and March 2000) significantly expanded cooperation to include all HEU fuel under RF Navy control. To date, it is estimated that tens of metric tons of HEU have been secured - enough to construct hundreds of nuclear devices. It was determined that the cooperation would be coordinated by the Russian Research Center, Kurchatov Institute. This paper describes the history of the Program development, its stages, current status, scale of the work and prospects.
Date: May 30, 2001
Creator: Nelson, N. N.; O'Shell, P.; Hendrickson, S.; Sukhoruchkin, V.; Antipov, S.; Melkhov, E. et al.
Object Type: Article
System: The UNT Digital Library
Diagnostic Systems Approach to Watershed Management (open access)

Diagnostic Systems Approach to Watershed Management

The water quality of discharge from the surface water system is ultimately dictated by land use and climate within the watershed. Water quality has vastly improved from point source reduction measures, yet, non-point source pollutants continue to rise. 30 to 40% of rivers still do not meet water quality standards for reasons that include impact from urban storm water runoff, agricultural and livestock runoff, and loss of wetlands. Regulating non-point source pollutants proves to be difficult since specific dischargers are difficult to identify. However, parameters such as dissolved organic carbon (DOC) limit the amounts of chlorination due to simultaneous disinfection by-product formation. The concept of watershed management has gained much ground over the years as a means to resolve non-point source problems. Under this management scheme stakeholders in a watershed collectively agree to the nature and extent of non-point sources, determine water quality causes using sound scientific approaches, and together develop and implement a corrective plan. However, the ''science'' of watershed management currently has several shortcomings according to a recent National Research Council report. The scientific component of watershed management depends on acquiring knowledge that links water quality sources with geographic regions. However, there is an observational gap in this …
Date: February 23, 2001
Creator: Davisson, M L
Object Type: Report
System: The UNT Digital Library
Physics and Applications of NIS Junctions (open access)

Physics and Applications of NIS Junctions

This paper reviews the physics and applications of Normal-Insulator-Superconductor (NIS) tunnel junctions. The current-voltage properties of NIS junctions are diode-like with a strong temperature dependence. Hence, these structures can be used as sensitive thermometers at temperatures well below the energy gap, {Delta}, of the superconducting electrode. For junction voltages comparable to {Delta}/q, current flow removes energy from the normal electrode. This property has been exploited to build refrigerators capable of cooling thin-film circuits from 0.3 K to 0.1 K. Calorimeters and bolometers for the detection of X-rays and millimeter-wave radiation, respectively, have successfully been built from NIS junctions. NIS junctions have also been used to probe the superconducting state. Finally, recent ideas for the use of NIS junctions as simple circuit elements are described.
Date: August 24, 2001
Creator: Ullom, J N
Object Type: Article
System: The UNT Digital Library
e+ e- collider in the VLHC tunnel. Proceedings, Workshop, Chicago, USA, March 9-11, 2001 (open access)

e+ e- collider in the VLHC tunnel. Proceedings, Workshop, Chicago, USA, March 9-11, 2001

This document is a collection of the contributions made to the March IIT workshop on an e{sup +}e{sup -} collider in the VLHC tunnel. This machine, which is based on a relatively conservative extrapolation of LEP technology, has a baseline luminosity of 10{sup 33}/cm{sup 2}/s at a CM energy of 370 GeV. The overall parameters and general description of such a machine is described in T. Sen and J. Norem, ''A Very Large Lepton Collider in the VLHC Tunnel'', to be published. A preprint of this paper is included as Appendix 2 of this report. The intention of the workshop was to define the parameters of such a collider and make them available to the community for use in further physics studies. It is clear that the machine cannot compete with a full scale linear collider. Its main interest would be if a VLHC were built and if a linear collider did not already exist. In this case, it could provide a limited and perhaps crucial view of low mass Higgs states. Although the study is incomplete, it does define rather well the parameters of the machine, as well as the challenges that the design faces. The study benefited greatly …
Date: July 1, 2001
Creator: Dugan, D., (ed.); /Cornell U., LEPP; Tollestrup, A., (ed.) & /Fermilab
Object Type: Article
System: The UNT Digital Library
Analysis of Fabry-Perot Velocimeter Records (open access)

Analysis of Fabry-Perot Velocimeter Records

Program demonstration and user instructions are presented for FabryVB5. This computer program was created for use in analyzing Fabry-Perot interferometer records that detail the velocity time histories of fast moving surfaces. Graphical curves representing peak fringe positions and fiducial timing dots are extracted from a digitized film record or from a CCD digital image. An analysis is demonstrated on a sample velocimeter record along with some mathematical formula and routine operations. Routines used to analyze calibration records on streak camera distortions are illustrated in an appendix. This is a Microsoft Visual Basic{trademark} version for the PC.
Date: August 3, 2001
Creator: Avara, G.
Object Type: Report
System: The UNT Digital Library
High-Resolution Adaptive Optics Test-Bed for Vision Science (open access)

High-Resolution Adaptive Optics Test-Bed for Vision Science

We discuss the design and implementation of a low-cost, high-resolution adaptive optics test-bed for vision research. It is well known that high-order aberrations in the human eye reduce optical resolution and limit visual acuity. However, the effects of aberration-free eyesight on vision are only now beginning to be studied using adaptive optics to sense and correct the aberrations in the eye. We are developing a high-resolution adaptive optics system for this purpose using a Hamamatsu Parallel Aligned Nematic Liquid Crystal Spatial Light Modulator. Phase-wrapping is used to extend the effective stroke of the device, and the wavefront sensing and wavefront correction are done at different wavelengths. Issues associated with these techniques will be discussed.
Date: September 27, 2001
Creator: Wilks, S. C.; Thomspon, C. A.; Olivier, S. S.; Bauman, B. J.; Barnes, T. & Werner, J. S.
Object Type: Article
System: The UNT Digital Library
The ASCI PSE Milepost: Run-Time Systems Performance Tests (open access)

The ASCI PSE Milepost: Run-Time Systems Performance Tests

The Accelerated Strategic Computing Initiative (ASCI) Problem Solving Environment (PSE) consists of the tools and libraries needed for the development of ASCI simulation codes on ASCI machines. The recently completed ASCI PSE Milepost demonstrated that this software environment is available and functional at the scale used for application mileposts on ASCI White. As part of the PSE Milepost, we performed extensive performance testing of several critical run-time based systems. In this paper, we present microbenchmark results that compare the MPI [5], Pthreads and OpenMP [7, 8] implementations on ASCI White and ASCI Blue Pacific. Our results demonstrate that these run-time systems on White have improved sufficiently to accommodate the machine's approximately four-fold increase in processing capability over Blue Pacific.
Date: May 7, 2001
Creator: de Supinski, B R
Object Type: Article
System: The UNT Digital Library
What is a Shock Wave to an Explosive Molecule? (open access)

What is a Shock Wave to an Explosive Molecule?

An explosive molecule is a metastable chemical species that reacts exothermically given the correct stimulus. Impacting an explosive with a shock wave is a ''wake-up call'' or ''trigger'' which compresses and heats the molecule. The energy deposited by the shock wave must be distributed to the vibrational modes of the explosive molecule before chemical reaction can occur. If the shock pressure and temperature are high enough and last long enough, exothermic chemical decomposition can lead to the formation of a detonation wave. For gaseous, liquid, and perfect single crystal solid explosives, after an induction time, chemical reaction begins at or near the rear boundary of the charge. This induction time can be calculated by high pressure, high temperature transition state theory. A ''superdetonation'' wave travels through the preshocked explosive until it overtakes the initial shock wave and then slows to the steady state Chapman-Jouguet (C-J) velocity. In heterogeneous solid explosives, initiation of reaction occurs at ''hot spots'' created by shock compression. If there is a sufficient number of large and hot enough ''hot spots,'' these ignition sites grow creating a pressure pulse that overtakes the leading shock front causing detonation. Since the chemical energy is released well behind the leading …
Date: June 12, 2001
Creator: Tarver, Craig M.
Object Type: Article
System: The UNT Digital Library
ERA-40 SST and Sea Ice Concentration Data (open access)

ERA-40 SST and Sea Ice Concentration Data

The lower boundary condition of sea surface temperature (SST) and sea-ice concentration (sic) is a critical forcing of the lower frequencies in multi-decadal global atmospheric reanalyses such as ERA-40. Partly in response to the ERA-40 project, new SST/sic data sets have been developed that are considerably improved over those available to the first-generation reanalyses. This paper documents the input SST/sic data sets and the processing that created the daily SST/sic specification for the ERA-40 period 1956-2001. The source data are: (1) the monthly mean HadISST data set from the UKMO Hadley Centre for 1956-1981; and (2) the weekly NCEP 2DVAR data for 1982-present. Both data sets are reanalyses of satellite and conventional SST/sic observations. The principal reason for the higher quality of these source data sets is the use of a common consensus sic and a common sic-SST relationship in the sea ice margins. The use of a common sic resulted in a very smooth transition between HadISST and NCEP 2DVAR, despite differences in data assimilation techniques and monthly versus weekly analyses. No special action was required to insure consistency at the transition unlike as was necessary for the AMIP II experiment (Fiorino, 1997). The only special processing was application …
Date: August 27, 2001
Creator: Fiorino, M
Object Type: Report
System: The UNT Digital Library
Detection of Pathogens Using a Handheld PCR Thermocycler (open access)

Detection of Pathogens Using a Handheld PCR Thermocycler

None
Date: May 14, 2001
Creator: Emanuel, P; Hadfield, T; Koopman, R; Richards, J; Benett, W; Stratton, P et al.
Object Type: Article
System: The UNT Digital Library