States

Simple scaling model for exploding pusher targets (open access)

Simple scaling model for exploding pusher targets

A simple model has been developed which when normalized by experiment or Lasnex calculations can be used to scale neutron yields for variations in laser input power and pulse length and target radius and wall thickness. The model also illucidates some of the physical processes occurring in this regime of laser fusion experiments. Within certain limitations on incident intensity and target geometry, the model scales with experiments and calculations to within a factor of two over six decades in neutron yield.
Date: November 4, 1977
Creator: Storm, E. K.; Larsen, J. T.; Nuckolls, J. H.; Ahlstrom, H. G. & Manes, K. R.
Object Type: Article
System: The UNT Digital Library
Preliminary plan for the development of geothermal energy in the town of Hawthorne, Nevada (open access)

Preliminary plan for the development of geothermal energy in the town of Hawthorne, Nevada

Site characteristics pertinent to the geothermal development are described, including: physiography, demography, economy, and goals and objectives of the citizens as they relate to geothermal development. The geothermal reservoir is characterized on the basis of available information. The probable drilling depth to the reservoir, anticipated water production rates, water quality, and resource temperature are indicated. Uses of the energy that seem appropriate to the situation both now and in the near future at Hawthorne are described. The essential institutional requirements for geothermal energy development are discussed, including the financial, environmental, and legal and regulatory aspects. The various steps that are necessary to accomplish the construction of the geothermal district heating system are described.
Date: November 4, 1981
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Magnet power control system for the Tandem Mirror Experiment-Upgrade (open access)

Magnet power control system for the Tandem Mirror Experiment-Upgrade

This paper describes the desktop computer/CAMAC-based system that controls the power source for the Tandem Mirror Experiment-Upgrade (TMX-U) magnet power system. Presently it contains 42 dc rectifier power supplies connected to 24 magnet coils arranged in 17 circuits. During each shot, the system delivers 22.6 MW dc to the magnets for about 3 s. The system is presently being changed to add six power supplies, two solenoidal throttle coils, and two reverse C-coils. When complete, the delivered power will increase to 36.9 MW. The closed-loop control system usually provides current (and thus, magnetic field) that is within 1% of the requested current. Achieving this accuracy required using grounding, shielding, and isolation methods to reduce noise and related problems. These are also discussed.
Date: November 4, 1983
Creator: Bell, H.H. Jr.
Object Type: Article
System: The UNT Digital Library
Pressure vessel fracture studies pertaining to a PWR LOCA-ECC thermal shock: experiments TSE-3 and TSE-4 and update of TSE-1 and TSE-2 analysis (open access)

Pressure vessel fracture studies pertaining to a PWR LOCA-ECC thermal shock: experiments TSE-3 and TSE-4 and update of TSE-1 and TSE-2 analysis

The LOCA-ECC Thermal Shock Program was established to investigate the potential for flaw propagation in pressurized-water reactor (PWR) vessels during injection of emergency core coolant following a loss-of-coolant accident. Studies thus far have included fracture mechanics analyses of typical PWRs, the design and construction of a thermal shock test facility, determination of material properties for test specimens, and four thermal shock experiments with 0.53-m-OD (21-in.) by 0.15-m-wall (6-in.) cylindrical test specimens. In the first experiment, initiation was not expected and did not occur, although there was a small amount of subcritical crack growth. In the second experiment, initiation of a semicircular flaw took place as expected; the final length along the surface was about four times the initial length, but there was no radial growth. The third and fourth experiments were similar, and the long axial flaw initiated in good agreement with predictions.
Date: November 4, 1977
Creator: Cheverton, R.D. & Bolt, S.E.
Object Type: Report
System: The UNT Digital Library
Preliminary plan for the development of geothermal energy in the town of Hawthorne, Nevada (open access)

Preliminary plan for the development of geothermal energy in the town of Hawthorne, Nevada

The results of the analyses as well as a plan for the development of the geothermal resource are described. Site characteristics pertinent to the geothermal development are described. These characteristics include physiography, demography, economy, and goals and ojectives of the citizens as they would relate to geothermal development. The geothermal resource is described. The reservoir is characterized on the basis of available information. The probable drilling depth to the reservoir, anticipated water production rates, water quality, and resource temperatures ae indicated. Uses of the energy that seem appropriate to the situation both now and in the near future at Hawthorne are described. The amounts and types of energy currently consumed by end users are estimated. Using this data base, conceptual engineering designs and cost estimates for three alternative district heating systems are presented. In addition, the results of a life cycle cost analysis for these alternatives are discussed. The essential institutional requirements for geothermal energy development, including the financial, environmental, and legal and regulatory aspects are discussed. The various steps that are necessary to accomplish the construction of the geothermal district heating system at Hawthorne are described. A time-line chart shows the tasks, the time estimated to be required for …
Date: November 4, 1981
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Scientific problems of fusion, solved and to be solved (open access)

Scientific problems of fusion, solved and to be solved

A good comprehensive review of research progress and the present status of research on inertial confinement, tokamak device, and magnetic mirror technology is given. (MOW)
Date: November 4, 1977
Creator: Post, Richard F.
Object Type: Article
System: The UNT Digital Library
Generalization of the ERIT principle and method. (open access)

Generalization of the ERIT principle and method.

The paper describes the generalization of the method to produce secondary particles with a low-energy and low-intensity primary beam circulating in a Storage Ring with the Emittance-Recovery by Internal-Target (ERIT).
Date: November 4, 2007
Creator: Ruggiero, A. G.
Object Type: Article
System: The UNT Digital Library
April 2008 Monitoring Report for Morrill, Kansas. (open access)

April 2008 Monitoring Report for Morrill, Kansas.

In September 2005, the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) initiated periodic sampling of groundwater in the vicinity of a grain storage facility formerly operated by the CCC/USDA at Morrill, Kansas. The sampling at Morrill is being performed on behalf of the CCC/USDA by Argonne National Laboratory, in accord with a monitoring program approved by the Kansas Department of Health and Environment (KDHE), to monitor levels of carbon tetrachloride contamination identified in the groundwater at this site (Argonne 2004, 2005a). This report provides results for the most recent monitoring event, in April 2008. Under the KDHE-approved monitoring plan (Argonne 2005b), groundwater was initially sampled twice yearly for a recommended period of two years (in fall 2005, in spring and fall 2006, and in spring and fall 2007). The samples were analyzed for volatile organic compounds (VOCs), as well as for selected geochemical parameters to aid in the evaluation of possible natural contaminant degradation (reductive dechlorination) processes in the subsurface environment. During the recommended two-year period, the originally approved scope of the monitoring was expanded to include vegetation sampling (initiated in October 2006) and surface water and stream bed sediment sampling (initiated in March 2007, after a …
Date: November 4, 2008
Creator: LaFreniere, L. M.
Object Type: Report
System: The UNT Digital Library
LOWER BOUNDS ON RING SELF-FOCUSING SO AS TO MAINTAIN RING INTEGRITY DURING SPILLOUT AND SUBSEQUENT ACCELERATION (open access)

LOWER BOUNDS ON RING SELF-FOCUSING SO AS TO MAINTAIN RING INTEGRITY DURING SPILLOUT AND SUBSEQUENT ACCELERATION

Relationships necessary for ring stability are derived between the self-focusing forces of an electron ring and the magnetic field gradient defocusing forces present near and just subsequent to spillout.
Date: November 4, 1969
Creator: Pellegrini, Claudio & Sessler, Andrew
Object Type: Report
System: The UNT Digital Library
Brines formed by multi-salt deliquescence (open access)

Brines formed by multi-salt deliquescence

The FY05 Waste Package Environment testing program at Lawrence Livermore National Laboratory focused on determining the temperature, relative humidity, and solution compositions of brines formed due to the deliquescence of NaCl-KNO{sub 3}-NaNO{sub 3} and NaCl-KNO{sub 3}-NaNO{sub 3}-Ca(NO{sub 3}){sub 2} salt mixtures. Understanding the physical and chemical behavior of these brines is important because they define conditions under which brines may react with waste canister surfaces. Boiling point experiments show that NaCl-KNO{sub 3}-NaNO{sub 3} and NaCl-KNO{sub 3}-NaNO{sub 3}-Ca(NO{sub 3}){sub 2} salt mixtures form brines that transform to hydrous melts that do not truly 'dry out' until temperatures exceed 300 and 400 C, respectively. Thus a conducting solution is present for these salt assemblages over the thermal history of the repository. The corresponding brines form at lower relative humidity at higher temperatures. The NaCl-KNO{sub 3}-NaNO{sub 3} salt mixture has a mutual deliquescence relative humidity (MDRH) of 25.9% at 120 C and 10.8% at 180 C. Similarly, the KNO{sub 3}-NaNO{sub 3} salt mixture has MDRH of 26.4% at 120 C and 20.0% at 150 C. The KNO{sub 3}-NaNO{sub 3} salt mixture salts also absorb some water (but do not appear to deliquesce) at 180 C and thus may also contribute to the transfer …
Date: November 4, 2005
Creator: Carroll, S; Rard, J; Alai, M & Staggs, K
Object Type: Report
System: The UNT Digital Library
Rapid Undercooling and Refreeze in Laser-Shock-Melted Bi(Zn) (open access)

Rapid Undercooling and Refreeze in Laser-Shock-Melted Bi(Zn)

We completed experiments in which we used a high-power laser to shock-melt a Bi(Zn) alloy and refreeze it in the shock release wave. We recovered the samples post shot for microscopic analysis and compared our results with the results from similar prior experiments with pure Bi. The targets in both sets of experiments were four-layer targets composed of BK7 glass, Al, the elemental Bi or Bi(Zn) alloy, and a transparent diagnostic window. There is conductive heating of the Bi through the Al layer from the hot plasma at the Al/BK7 boundary that depends on the Al thickness. Since the Bi(Zn) targets had a much thicker Al layer than did the Bi targets, the two sets of targets had somewhat different thermal histories even though they were driven to the same pressure. In this presentation we compare the resolidified Bi(Zn) microstructure to that of the Bi, accounting for the different thermal histories.
Date: November 4, 2005
Creator: Jankowski, Alan Frederic; Colvin, J.; Reed, B. & Kumar, M.
Object Type: Article
System: The UNT Digital Library
Updates to the ORIGEN-S Cross-Section Libraries Using ENDF-VI, EAF-99, and FENDL-2.0 (open access)

Updates to the ORIGEN-S Cross-Section Libraries Using ENDF-VI, EAF-99, and FENDL-2.0

The standard cross-section library for light-water reactor (LWR) analyses used by the ORIGEN-S depletion and decay code has been extensively updated. This work entailed the development of broad multigroup neutron cross sections for ORIGEN-S from several sources of pointwise continuous-energy cross-section evaluations, including the U.S. Evaluated Nuclear Data Files ENDF/B-VI Release 7, the Fusion Evaluated Nuclear Data Library FENDL-2.0, and the European Activation File EAF-99. The pointwise cross sections were collapsed to a three-group structure using a continuous-energy neutron flux spectrum representative of the typical neutronic conditions of typical LWR fuel and formatted for use by ORIGEN-S. In addition, the fission-product library has been expanded to include ENDF/B-VI fission yield data for 30 fissionable actinides. The processing codes and procedures are explained. Preliminary verification studies using the updated libraries were performed using the modules of the SCALE (Standardized Computer Analyses for Licensing Evaluation) system. Comparisons between the previous basic ORIGEN-S libraries and the updated libraries developed in this work are presented.
Date: November 4, 2004
Creator: Murphy, B. D.
Object Type: Report
System: The UNT Digital Library
Age validation of canary rockfish (Sebastes pinniger) using two independent otolith techniques: lead-radium and bomb radiocarbon dating. (open access)

Age validation of canary rockfish (Sebastes pinniger) using two independent otolith techniques: lead-radium and bomb radiocarbon dating.

Canary rockfish (Sebastes pinniger) have long been an important part of recreational and commercial rockfish fishing from southeast Alaska to southern California, but localized stock abundances have declined considerably. Based on age estimates from otoliths and other structures, lifespan estimates vary from about 20 years to over 80 years. For the purpose of monitoring stocks, age composition is routinely estimated by counting growth zones in otoliths; however, age estimation procedures and lifespan estimates remain largely unvalidated. Typical age validation techniques have limited application for canary rockfish because they are deep dwelling and may be long lived. In this study, the unaged otolith of the pair from fish aged at the Department of Fisheries and Oceans Canada was used in one of two age validation techniques: (1) lead-radium dating and (2) bomb radiocarbon ({sup 14}C) dating. Age estimate accuracy and the validity of age estimation procedures were validated based on the results from each technique. Lead-radium dating proved successful in determining a minimum estimate of lifespan was 53 years and provided support for age estimation procedures up to about 50-60 years. These findings were further supported by {Delta}{sup 14}C data, which indicated a minimum estimate of lifespan was 44 {+-} 3 …
Date: November 4, 2007
Creator: Andrews, A H; Kerr, L A; Cailliet, G M; Brown, T A; Lundstrom, C C & Stanley, R D
Object Type: Article
System: The UNT Digital Library
Coherent States and Spontaneous Symmetry Breaking in Light Front Scalar Field Theory (open access)

Coherent States and Spontaneous Symmetry Breaking in Light Front Scalar Field Theory

None
Date: November 4, 2005
Creator: Vary, J P; Chakrabarti, D; Harindranath, A; Lloyd, R; Martinovic, L & Spence, J R
Object Type: Article
System: The UNT Digital Library
RESULTS OF GROUNDWATER MONITORING FOR THE 183-H SOLAR EVAPORATION BASINS AND 300 AREA PROCESS TRENCHES JANUARY THRU JUNE 2008 (open access)

RESULTS OF GROUNDWATER MONITORING FOR THE 183-H SOLAR EVAPORATION BASINS AND 300 AREA PROCESS TRENCHES JANUARY THRU JUNE 2008

This is one of a series of reports on Resource Conservation and Recovery Act of 1976 (RCRA) monitoring at the 183-H solar evaporation basins and the 300 Area process trenches. It fulfills the requirement of Washington Administrative Code (WAC) 173-303-645(11)(g), 'Release from Regulated Units', to report twice each year on the effectiveness of the corrective action program. This report covers the period from January through June 2008. The current objective of corrective action monitoring the 183-H basins is simply to track trends. Although there is short-term variability in contaminant concentrations, trends over the past 10 years are downward. The current Hanford Facility RCRA Permit (Dangerous Waste Portion of the Resource Conservation and Recovery Act Permit for the Treatment, Storage, and Disposal of Dangerous Waste [Permit No. WA 7890008967]) and monitoring plan remain adequate for the objective of tracking trends. The objective of groundwater monitoring at the 300 Area process trenches is to demonstrate the effectiveness of the corrective action program by examining the trend of the constituents of interest to confirm that they are attenuating naturally. The overall concentration of uranium in network wells remained above the 30 {micro}g/L drinking water standard in the three downgradient wells screened at the …
Date: November 4, 2008
Creator: MJ, HARTMAN
Object Type: Report
System: The UNT Digital Library
FutureGen: Pathway to Near-Zero Emissions and Sustainable Energy (open access)

FutureGen: Pathway to Near-Zero Emissions and Sustainable Energy

This presentation will highlight the U.S. Department of Energy’s (DOE) FutureGen project − a $1 billion government-industry partnership to design, build, and operate a near-zero emissions coal-fueled power plant. The lead organization for the FutureGen initiative is the National Energy Technology Laboratory (NETL), a multi-purpose laboratory operated by the U.S. DOE’s Office of Fossil Energy. NETL has a mission to conduct R&D from fundamental science to technology demonstration for resolving the environmental, supply, and reliability constraints of producing and using fossil energy resources. The commercial-scale FutureGen R&D facility is a pathway toward future fossil-energy power plants that will produce hydrogen and electricity while nearly eliminating emissions, including carbon dioxide. The 275-megawatt FutureGen plant will initiate operations around 2012 and employ advanced coal gasification technology integrated with combined cycle electricity generation, hydrogen production, and carbon capture and sequestration. Low carbon emissions would be achieved by integrating CO2 capture and sequestration operations with the power plant.
Date: November 4, 2007
Creator: Zitney, S. E. & Sarkus, T. A
Object Type: Article
System: The UNT Digital Library
Surface and bulk contribution to Cu(111) quantum efficiency (open access)

Surface and bulk contribution to Cu(111) quantum efficiency

The quantum efficiency (QE) of Cu(111) is measured for different impinging light angles with photon energies just above the work function. We observe that the vectorial photoelectric effect, an enhancement of the QE due to illumination with light with an electric vector perpendicular to the sample surface, is stronger in the more surface sensitive regime. This can be explained by a contribution to photoemission due to the variation in the electromagnetic potential at the surface. The contributions of bulk and surface electrons can then be determined.
Date: November 4, 2008
Creator: Pedersoli, Emanuele; Greaves, Corin Michael Ricardo; Wan, Weishi; Coleman-Smith, Christopher; Padmore, Howard A.; Pagliara, Stefania et al.
Object Type: Article
System: The UNT Digital Library
Coordination of 1,4-Diazabutadiene Ligands to Decamethylytterbocene: Additional Examples of Spin Coupling in Ytterbocene Complexes (open access)

Coordination of 1,4-Diazabutadiene Ligands to Decamethylytterbocene: Additional Examples of Spin Coupling in Ytterbocene Complexes

The paramagnetic 1:1 coordination complexes of (C5Me5)2Yb with a series of diazabutadiene ligands, RN=C(R')C(R')=NR, where R= CMe3, CHMe2, adamantyl, p-tolyl, p-anisyl, and mesityl when R'=H, and R= p-anisyl when R'= Me, have been prepared. The complexes are paramagnetic, but their magnetic moments are less than expected for the two uncoupled spin carriers, (C5Me5)2Yb(III, 4f13) and the diazabutadiene radical anions (S=1/2), which implies exchange coupling between the spins. The variable temperature 1H NMR spectra show that rotation about the R-N bond is hindered and these barriers are estimated. The barriers are largely determined by steric effects but electronic effects are not unimportant.
Date: November 4, 2006
Creator: Andersen, Richard; Walter, Marc D.; Berg, David J. & Andersen, Richard A.
Object Type: Article
System: The UNT Digital Library
Nuclear and Radiological Forensics and Attribution Overview (open access)

Nuclear and Radiological Forensics and Attribution Overview

The goal of the U.S. Department of Homeland Security (DHS) Nuclear and Radiological Forensics and Attribution Program is to develop the technical capability for the nation to rapidly, accurately, and credibly attribute the origins and pathways of interdicted or collected materials, intact nuclear devices, and radiological dispersal devices. A robust attribution capability contributes to threat assessment, prevention, and deterrence of nuclear terrorism; it also supports the Federal Bureau of Investigation (FBI) in its investigative mission to prevent and respond to nuclear terrorism. Development of the capability involves two major elements: (1) the ability to collect evidence and make forensic measurements, and (2) the ability to interpret the forensic data. The Program leverages the existing capability throughout the U.S. Department of Energy (DOE) national laboratory complex in a way that meets the requirements of the FBI and other government users. At the same time the capability is being developed, the Program also conducts investigations for a variety of sponsors using the current capability. The combination of operations and R&D in one program helps to ensure a strong linkage between the needs of the user community and the scientific development.
Date: November 4, 2005
Creator: Smith, D K & Niemeyer, S
Object Type: Report
System: The UNT Digital Library
Analysis of how changed federal regulations and economic incentives affect financing of geothermal projects (open access)

Analysis of how changed federal regulations and economic incentives affect financing of geothermal projects

The effects of various financial incentives on potential developers of geothermal electric energy are studied and the impact of timing of plant construction costs on geothermal electricity costs is assessed. The effect of the geothermal loan guarantee program on decisions by investor-owned utilities to build geothermal electric power plants was examined. The usefulness of additional investment tax credits was studied as a method for encouraging utilities to invest in geothermal energy. The independent firms which specialize in geothermal resource development are described. The role of municipal and cooperative utilities in geothermal resource development was assessed in detail. Busbar capital costs were calculated for geothermal energy under a variety of ownerships with several assumptions about financial incentives. (MHR)
Date: November 4, 1980
Creator: Meyers, D.; Wiseman, E. & Bennett, V.
Object Type: Report
System: The UNT Digital Library
Benefits of recycling galvanized steel scrap for recovery of high-quality steel and zinc metal (open access)

Benefits of recycling galvanized steel scrap for recovery of high-quality steel and zinc metal

Argonne National Laboratory (ANL) and Metal Recovery Industries, Inc. (MRII), in cost-sharing collaboration, have developed an electrolytic process to separate and recover steel and zinc from galvanized steel scrap. This work has been supported by the US DOE. An assessment of available dezinc technology was begun in 1987 which (1) screened process concepts for separating and recovering zinc and steel from galvanized ferrous scrap, (2) selected electrochemical stripping in hot caustic as the most promising process, (3) evaluated the technical and economic feasibility of the selected process on the basis of fundamental electrochemical studies, (4) experimentally verified the technical and economic feasibility of the process in a phased evaluation from bench-scale controlled experiments through batch tests of actual scrap up to six ton lots, and (5) concluded that the process has technical and economic merit and requires larger- scale evaluation in a continuous mode as the final phase of process development. This work has attracted worldwide interest. Preliminary economic analysis indicates that the cost of the recovered ferrous scrap would be about $150/ton (at a base cost of $110/ton for galvanized scrap), including credit for the co-product zinc. Concentrations of zinc, lead, cadmium and other coating constituents on loose scrap …
Date: November 4, 1991
Creator: Dudek, F.J.; Daniels, E.J. (Argonne National Lab., IL (United States)) & Morgan, W.A. (Metal Recovery Industries, Inc., Hamilton, ON (Canada))
Object Type: Article
System: The UNT Digital Library
Freeze-protection loop for direct solar-water-heating systems. Final report (open access)

Freeze-protection loop for direct solar-water-heating systems. Final report

Even a one-time freeze condition can do destructive damage to a direct solar water heating system. The project funded under grant DE-FG4480R4, 1-1-80 to 8-1-81, proposed to demonstrate a simple installation procedure whereby thermosiphoning warm water from storage would prevent solar collectors from freezing. Installing the freeze protection loop in owner maintained solar systems was inconclusive. Owners were not attentive to freeze warnings or did not understand the simple instructions. A controlled situation was established using a refrigerator to produce below freezing temperatures. Experiments conducted with this equipment showed that the thermosiphoning principle could not be relied on to prevent freezing. Thermosiphoning cannot be relied on to prevent freezing in a direct solar water heating system. The direct system is an effective means of heating water in north Florida, but the system must be drained, either manually or automatically, to provide reliable system protection.
Date: November 4, 1981
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Solar oscillations, gravitational multipole field of the sun and the solar neutrino paradox (open access)

Solar oscillations, gravitational multipole field of the sun and the solar neutrino paradox

The visual solar oblateness work and the solar seismological work on the internal rotation of the sun are reviewed and their implications concerning the static gravitational multipole moments of the sun are discussed. The results of this work are quite deviant which is indicative of the complexity encountered and of the necessity for continued studies based on a diverse set of observing techniques. The evidence for phase-locked internal gravity modes of the sun is reviewed and the implications for the solar neutrino paradox are discussed. The rather unique possibility for testing the relevance which the phase-locked gravity modes have to this paradox is also noted. The oscillating perturbations in the sun's gravitational field produced by the classified internal gravity modes and the phase-locked modes are inferred from the observed temperature eigenfunctions. Strains of the order of 10/sup -18/ in gravitational radiation detectors based on free masses are inferred for frequencies near 100 ..mu..Hz. The relevance of these findings is discussed in terms of a new technique for use in solar seismological studies and of producing background signals in studies of low-frequency gravitational radiation. 64 refs., 2 figs.
Date: November 4, 1986
Creator: Hill, H.A. & Rosenwald, R.D.
Object Type: Article
System: The UNT Digital Library
Modification of the hydriding of uranium using ion implantation (open access)

Modification of the hydriding of uranium using ion implantation

The hydriding of depleted uranium at 76 Torr hydrogen and 130/sup 0/C has been significantly reduced by implantation of oxygen ions. The high-dose implanted specimens had incubation times for the initiation of the reaction after exposure to hydrogen that exceeded those of the nonimplanted specimens by more than a factor of eight. Furthermore, the nonimplanted specimens consumed enough hydrogen to cause macroscopic flaking of essentially the entire surface in times much less than the incubation time for the high-dose implanted specimens. In contrast, the ion-implanted specimens reacted only at isolated spots with the major fraction of the surface area unaffected by the hydrogen exposure.
Date: November 4, 1983
Creator: Musket, R.G.; Robinson-Weis, G. & Patterson, R.G.
Object Type: Article
System: The UNT Digital Library