Sodium-Beta Batteries for Grid-Scale Storage: Planar Sodium-Beta Batteries for Renewable Integration and Grid Applications (open access)

Sodium-Beta Batteries for Grid-Scale Storage: Planar Sodium-Beta Batteries for Renewable Integration and Grid Applications

Broad Funding Opportunity Announcement Project: EaglePicher is developing a sodium-beta alumina (Na-Beta) battery for grid-scale energy storage. High-temperature Na-Beta batteries are a promising grid-scale energy storage technology, but existing approaches are expensive and unreliable. EaglePicher has modified the shape of the traditional, tubular-shaped Na-Beta battery. It is using an inexpensive stacked design to improve performance at lower temperatures, leading to a less expensive overall storage technology. The new design greatly simplifies the manufacturing process for beta alumina membranes (a key enabling technology), providing a subsequent pathway to the production of scalable, modular batteries at half the cost of the existing tubular designs.
Date: February 1, 2010
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Closures for Course-Grid Simulation of Fluidized Gas-Particle Flows (open access)

Closures for Course-Grid Simulation of Fluidized Gas-Particle Flows

Gas-particle flows in fluidized beds and riser reactors are inherently unstable, and they manifest fluctuations over a wide range of length and time scales. Two-fluid models for such flows reveal unstable modes whose length scale is as small as ten particle diameters. Yet, because of limited computational resources, gas-particle flows in large fluidized beds are invariably simulated by solving discretized versions of the two-fluid model equations over a coarse spatial grid. Such coarse-grid simulations do not resolve the small-scale spatial structures which are known to affect the macroscale flow structures both qualitatively and quantitatively. Thus there is a need to develop filtered two-fluid models which are suitable for coarse-grid simulations and capturing the effect of the small-scale structures through closures in terms of the filtered variables. The overall objective of the project is to develop validated closures for filtered two-fluid models for gas-particle flows, with the transport gasifier as a primary, motivating example. In this project, highly resolved three-dimensional simulations of a kinetic theory based two-fluid model for gas-particle flows have been performed and the statistical information on structures in the 100-1000 particle diameters length scale has been extracted. Based on these results, closures for filtered two-fluid models have been …
Date: February 14, 2010
Creator: Sundaresan, Sankaran
Object Type: Report
System: The UNT Digital Library
Magnetic stochasticity in gyrokinetic simulations of plasma microturbulence (open access)

Magnetic stochasticity in gyrokinetic simulations of plasma microturbulence

Analysis of the magnetic field structure from electromagnetic simulations of tokamak ion temperature gradient turbulence demonstrates that the magnetic field can be stochastic even at very low plasma pressure. The degree of magnetic stochasticity is quantified by evaluating the magnetic diffusion coefficient. We find that the magnetic stochasticity fails to produce a dramatic increase in the electron heat conductivity because the magnetic diffusion coefficient remains small.
Date: February 12, 2010
Creator: Nevins, W M; Wang, E & Candy, J
Object Type: Article
System: The UNT Digital Library
AFIP-2 Fabrication Summary Report (open access)

AFIP-2 Fabrication Summary Report

The Advanced Test Reactor (ATR) Full-size Plate In Center Flux Trap Position (AFIP)-2 experiment was designed to evaluate the performance of monolithic fuels at a scale prototypic of research reactor fuel plates. Two qualified fueled plates were fabricated for the AFIP 2 experiment to be irradiated in the Idaho National Laboratory ATR. This report provides details of the fuel fabrication efforts, including material selection, fabrication processes, and fuel plate qualification.
Date: February 1, 2010
Creator: Moore, Glenn
Object Type: Report
System: The UNT Digital Library
EVALUATION OF PLUTONIUM OXIDE DESTRUCTIVE CHEMICAL ANALYSES FOR VALIDITY OF ORIGINAL 3013 CONTAINER BINNING (open access)

EVALUATION OF PLUTONIUM OXIDE DESTRUCTIVE CHEMICAL ANALYSES FOR VALIDITY OF ORIGINAL 3013 CONTAINER BINNING

The surveillance program for 3013 containers is based, in part, on the separation of containers into various bins related to potential container failure mechanisms. The containers are assigned to bins based on moisture content and pre-storage estimates of content chemistry. While moisture content is measured during the packaging of each container, chemistry estimates are made by using a combination of process knowledge, packaging data and prompt gamma analyses to establish the moisture and chloride/fluoride content of the materials. Packages with high moisture and chloride/fluoride contents receive more detailed surveillances than packages with less chloride/fluoride and/or moisture. Moisture verification measurements and chemical analyses performed during the surveillance program provided an opportunity to validate the binning process. Validation results demonstrated that the binning effort was generally successful in placing the containers in the appropriate bin for surveillance and analysis.
Date: February 1, 2010
Creator: Mcclard, J. & Kessinger, G.
Object Type: Article
System: The UNT Digital Library
Algorithm Summary and Evaluation: Automatic Implementation of Ringdown Analysis for Electromechanical Mode Identification from Phasor Measurements (open access)

Algorithm Summary and Evaluation: Automatic Implementation of Ringdown Analysis for Electromechanical Mode Identification from Phasor Measurements

Small signal stability problems are one of the major threats to grid stability and reliability. Prony analysis has been successfully applied on ringdown data to monitor electromechanical modes of a power system using phasor measurement unit (PMU) data. To facilitate an on-line application of mode estimation, this paper develops a recursive algorithm for implementing Prony analysis and proposed an oscillation detection method to detect ringdown data in real time. By automatically detecting ringdown data, the proposed method helps guarantee that Prony analysis is applied properly and timely on the ringdown data. Thus, the mode estimation results can be performed reliably and timely. The proposed method is tested using Monte Carlo simulations based on a 17-machine model and is shown to be able to properly identify the oscillation data for on-line application of Prony analysis. In addition, the proposed method is applied to field measurement data from WECC to show the performance of the proposed algorithm.
Date: February 28, 2010
Creator: Zhou, Ning; Huang, Zhenyu; Tuffner, Francis K.; Jin, Shuangshuang; Lin, Jenglung & Hauer, Matthew L.
Object Type: Report
System: The UNT Digital Library
Energy storage for the electricity grid : benefits and market potential assessment guide : a study for the DOE Energy Storage Systems Program. (open access)

Energy storage for the electricity grid : benefits and market potential assessment guide : a study for the DOE Energy Storage Systems Program.

This guide describes a high-level, technology-neutral framework for assessing potential benefits from and economic market potential for energy storage used for electric-utility-related applications. The overarching theme addressed is the concept of combining applications/benefits into attractive value propositions that include use of energy storage, possibly including distributed and/or modular systems. Other topics addressed include: high-level estimates of application-specific lifecycle benefit (10 years) in $/kW and maximum market potential (10 years) in MW. Combined, these criteria indicate the economic potential (in $Millions) for a given energy storage application/benefit. The benefits and value propositions characterized provide an important indication of storage system cost targets for system and subsystem developers, vendors, and prospective users. Maximum market potential estimates provide developers, vendors, and energy policymakers with an indication of the upper bound of the potential demand for storage. The combination of the value of an individual benefit (in $/kW) and the corresponding maximum market potential estimate (in MW) indicates the possible impact that storage could have on the U.S. economy. The intended audience for this document includes persons or organizations needing a framework for making first-cut or high-level estimates of benefits for a specific storage project and/or those seeking a high-level estimate of viable price …
Date: February 1, 2010
Creator: Eyer, James M. & Corey, Garth P.
Object Type: Report
System: The UNT Digital Library
NONDESTRUCTIVE EXAMINATION OF PLUTONIUM-BEARING MATERIAL CONTAINERS (open access)

NONDESTRUCTIVE EXAMINATION OF PLUTONIUM-BEARING MATERIAL CONTAINERS

The first nondestructive examination (NDE) of 3013-type containers as part of the Department of Energy's (DOE's) Integrated Surveillance Program (ISP) was performed in February, 2005. Since that date 280 NDE surveillances on 255 containers have been conducted. These containers were packaged with plutonium-bearing materials at multiple DOE sites. The NDE surveillances were conducted at Hanford, Lawrence Livermore National Laboratory (LLNL), and Savannah River Site (SRS). These NDEs consisted of visual inspection, mass verification, radiological surveys, prompt gamma analysis, and radiography. The primary purpose of performing NDE surveillances is to determine if there has been a significant pressure buildup inside the inner 3013 container. This is done by measuring the lid deflection of the inner 3013 container using radiography images. These lid deflection measurements are converted to pressure measurements to determine if a container has a pressure of a 100 psig or greater. Making this determination is required by Surveillance and Monitoring Plan (S&MP). All 3013 containers are designed to withstand at least 699 psig as specified by DOE-STD-3013. To date, all containers evaluated have pressures under 50 psig. In addition, the radiography is useful in evaluating the contents of the 3013 container as well as determining the condition of the …
Date: February 1, 2010
Creator: Yerger, L.; Mcclard, J.; Traver, L. & Grim, T.
Object Type: Article
System: The UNT Digital Library
Micrometeorite Impacts in Beringian Mammoth Tusks and a Bison Skull (open access)

Micrometeorite Impacts in Beringian Mammoth Tusks and a Bison Skull

We have discovered what appear to be micrometeorites imbedded in seven late Pleistocene Alaskan mammoth tusks and a Siberian bison skull. The micrometeorites apparently shattered on impact leaving 2 to 5 mm hemispherical debris patterns surrounded by carbonized rings. Multiple impacts are observed on only one side of the tusks and skull consistent with the micrometeorites having come from a single direction. The impact sites are strongly magnetic indicating significant iron content. We analyzed several imbedded micrometeorite fragments from both tusks and skull with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and X-ray fluorescence (XRF). These analyses confirm the high iron content and indicate compositions highly enriched in nickel and depleted in titanium, unlike any natural terrestrial sources. In addition, electron microprobe (EMP) analyses of a Fe-Ni sulfide grain (tusk 2) show it contains between 3 and 20 weight percent Ni. Prompt gamma-ray activation analysis (PGAA) of a particle extracted from the bison skull indicates ~;;0.4 mg of iron, in agreement with a micrometeorite ~;;1 mm in diameter. In addition, scanning electron microscope (SEM) images and XRF analyses of the skull show possible entry channels containing Fe-rich material. The majority of tusks (5/7) have a calibrated weighted mean 14C …
Date: February 3, 2010
Creator: Hagstrum, Jonathon T.; Firestone, Richard B; West, Allen; Stefanka, Zsolt & Revay, Zsolt
Object Type: Article
System: The UNT Digital Library
Addressing the Federal-State-Local Interface Issues During a Catastrophic Event Such as an Anthrax Attack (open access)

Addressing the Federal-State-Local Interface Issues During a Catastrophic Event Such as an Anthrax Attack

On October 9, 2008, federal, state and local policy makers, emergency managers, and medical and public health officials convened in Seattle, Washington, for a workshop on Addressing the Federal-State-Local Interface Issues During a Catastrophic Event Such as an Anthrax Attack. The day-long symposium was aimed at generating a dialogue about recovery and restoration through a discussion of the associated challenges that impact entire communities, including people, infrastructure, and critical systems. The Principal Federal Official (PFO) provided an overview of the role of the PFO in a catastrophic event. A high-level summary of an anthrax scenario was presented. The remainder of the day was focused on interactive discussions among federal, state and local emergency management experts in the areas of: • Decision-making, prioritization, and command and control • Public health/medical services • Community resiliency and continuity of government. Key topics and issues that resulted from discussions included: • Local representation in the Joint Field Office (JFO) • JFO transition to the Long-Term Recovery Office • Process for prioritization of needs • Process for regional coordination • Prioritization - process and federal/military intervention • Allocation of limited resources • Re-entry decision and consistency • Importance of maintaining a healthy hospital system • …
Date: February 1, 2010
Creator: Stein, Steven L.; Lesperance, Ann M. & Upton, Jaki F.
Object Type: Report
System: The UNT Digital Library
TOXNET and Beyond - Using the NLMs Environmental Health and Toxicology Portal-February (open access)

TOXNET and Beyond - Using the NLMs Environmental Health and Toxicology Portal-February

The purpose of this training is to familiarize participants with reliable online environmental health and toxicology information, from the National Library of Medicine and other reliable sources. Skills and knowledge acquired in this training class will enable participants to access, utilize, and refer others to environmental health and toxicology information.
Date: February 24, 2010
Creator: Templin-Branner, W.
Object Type: Book
System: The UNT Digital Library
More Efficient Power Conversion for EVs: Gallium-Nitride Advanced Power Semiconductor and Packaging (open access)

More Efficient Power Conversion for EVs: Gallium-Nitride Advanced Power Semiconductor and Packaging

Broad Funding Opportunity Announcement Project: Delphi is developing power converters that are smaller and more energy efficient, reliable, and cost-effective than current power converters. Power converters rely on power transistors which act like a very precisely controlled on-off switch, controlling the electrical energy flowing through an electrical circuit. Most power transistors today use silicon (Si) semiconductors. However, Delphi is using semiconductors made with a thin layer of gallium-nitride (GaN) applied on top of the more conventional Si material. The GaN layer increases the energy efficiency of the power transistor and also enables the transistor to operate at much higher temperatures, voltages, and power-density levels compared to its Si counterpart. Delphi is packaging these high-performance GaN semiconductors with advanced electrical connections and a cooling system that extracts waste heat from both sides of the device to further increase the device’s efficiency and allow more electrical current to flow through it. When combined with other electronic components on a circuit board, Delphi’s GaN power transistor package will help improve the overall performance and cost-effectiveness of HEVs and EVs.
Date: February 1, 2010
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Energy Recovery Linac: G5 Test and Commissioning Plan (open access)

Energy Recovery Linac: G5 Test and Commissioning Plan

N/A
Date: February 1, 2010
Creator: E., Pozdeyev & Kayran, D.
Object Type: Report
System: The UNT Digital Library
Efficient Windows Collaborative: Research Tool Dissemination to Increase Energy Efficient Fenestration Product Penetration (open access)

Efficient Windows Collaborative: Research Tool Dissemination to Increase Energy Efficient Fenestration Product Penetration

The project goals covered both the residential and commercial windows markets and involved a range of audiences such as window manufacturers, builders, homeowners, design professionals, utilities, and public agencies. Essential goals included: (1) Creation of 'Master Toolkits' of information that integrate diverse tools, rating systems, and incentive programs, customized for key audiences such as window manufacturers, design professionals, and utility programs. (2) Delivery of education and outreach programs to multiple audiences through conference presentations, publication of articles for builders and other industry professionals, and targeted dissemination of efficient window curricula to professionals and students. (3) Design and implementation of mechanisms to encourage and track sales of more efficient products through the existing Window Products Database as an incentive for manufacturers to improve products and participate in programs such as NFRC and ENERGY STAR. (4) Development of utility incentive programs to promote more efficient residential and commercial windows. Partnership with regional and local entities on the development of programs and customized information to move the market toward the highest performing products. An overarching project goal was to ensure that different audiences adopt and use the developed information, design and promotion tools and thus increase the market penetration of energy efficient fenestration …
Date: February 28, 2010
Creator: Alliance to Save Energy (U.S.)
Object Type: Report
System: The UNT Digital Library
R&D PROPOSAL FOR THE NATIONAL MUON ACCELERATOR PROGRAM (open access)

R&D PROPOSAL FOR THE NATIONAL MUON ACCELERATOR PROGRAM

This document contains a description of a multi-year national R&D program aimed at completing a Design Feasibility Study (DFS) for a Muon Collider and, with international participation, a Reference Design Report (RDR) for a muon-based Neutrino Factory. It also includes the supporting component development and experimental efforts that will inform the design studies and permit an initial down-selection of candidate technologies for the ionization cooling and acceleration systems. We intend to carry out this plan with participants from the host national laboratory (Fermilab), those from collaborating U.S. national laboratories (ANL, BNL, Jlab, LBNL, and SNAL), and those from a number of other U.S. laboratories, universities, and SBIR companies. The R&D program that we propose will provide the HEP community with detailed information on future facilities based on intense beams of muons--the Muon Collider and the Neutrino Factory. We believe that these facilities offer the promise of extraordinary physics capabilities. The Muon Collider presents a powerful option to explore the energy frontier and the Neutrino Factory gives the opportunity to perform the most sensitive neutrino oscillation experiments possible, while also opening expanded avenues for the study of new physics in the neutrino sector. The synergy between the two facilities presents the …
Date: February 24, 2010
Creator: Program, Muon Accelerator; Zisman, Michael S. & Geer, Stephen
Object Type: Report
System: The UNT Digital Library
Lead-Cooled Fast Reactor (LFR) Design: Safety, Neutronics, Thermal Hydraulics, Structural Mechanics, Fuel, Core, and Plant Design (open access)

Lead-Cooled Fast Reactor (LFR) Design: Safety, Neutronics, Thermal Hydraulics, Structural Mechanics, Fuel, Core, and Plant Design

Fifth chapter from "A Compendium of Reactor Technology" discussing the history and design of lead-cooled fast reactors in nine sections: Lead-cooled Fast Reactor (LFR) Development, Design Criteria and General Specifications, Neutronics, Lead Properties, Compatibility of Structural Materials with Lead, Core, Reactor System, Decay Heat Removal System, and Nuclear Island.
Date: February 22, 2010
Creator: Smith, Craig; Cinotti, L.; Artoli, C. & Grasso, G.
Object Type: Book Chapter
System: The UNT Digital Library
Enhancement of Solar Energy Representation in the GCAM Model (open access)

Enhancement of Solar Energy Representation in the GCAM Model

The representation of solar technologies in a research version of the GCAM (formerly MiniCAM) integrated assessment model have been enhanced to add technologies, improve the underlying data, and improve the interaction with the rest of the model. We find that the largest potential impact from the inclusion of thermal Concentrating Solar Power plants, which supply a substantial portion of electric generation in sunny regions of the world. Drawing on NREL research, domestic Solar Hot Water technologies have also been added in the United States region where this technology competes with conventional electric and gas technologies. PV technologies are as implemented in the CCTP scenarios, drawing on NREL cost curves for the United States, extrapolated to other world regions using a spatial analysis of population and solar resources.
Date: February 1, 2010
Creator: Smith, Steven J.; Volke, April C. & Delgado Arias, Sabrina
Object Type: Report
System: The UNT Digital Library
Precision Engineering within the National Ignition Campaign (open access)

Precision Engineering within the National Ignition Campaign

In this very brief talk, we'll discuss how precision engineering impacts 4 key areas of NIF: (1) Diamond turning of KDP crystals; (2) Mitigation of laser damage on optics; (3) Alignment of lasers, targets, diagnostics; (4) Target fabrication.
Date: February 17, 2010
Creator: Taylor, J S; Carlisle, K; Klingmann, J L; Geraghty, P; Saito, T T & Montesanti, R C
Object Type: Article
System: The UNT Digital Library
Modeling and simulation for cyber-physical system security research, development and applications. (open access)

Modeling and simulation for cyber-physical system security research, development and applications.

This paper describes a new hybrid modeling and simulation architecture developed at Sandia for understanding and developing protections against and mitigations for cyber threats upon control systems. It first outlines the challenges to PCS security that can be addressed using these technologies. The paper then describes Virtual Control System Environments (VCSE) that use this approach and briefly discusses security research that Sandia has performed using VCSE. It closes with recommendations to the control systems security community for applying this valuable technology.
Date: February 1, 2010
Creator: Pollock, Guylaine M.; Atkins, William Dee; Schwartz, Moses Daniel; Chavez, Adrian R.; Urrea, Jorge Mario; Pattengale, Nicholas et al.
Object Type: Report
System: The UNT Digital Library
Extreme Ultraviolet Laser-based Table-top Aerial Image Metrology of Lithographic Masks (open access)

Extreme Ultraviolet Laser-based Table-top Aerial Image Metrology of Lithographic Masks

We report the first at-wavelength line edge roughness measurements of patterned EUV lithography masks realized using a table-top aerial imaging system based on a table-top {lambda}=13.2 laser.
Date: February 10, 2010
Creator: Brizuela, F.; Carbajo, S.; Sakdinawat, A.; Wang, Y.; Alessi, D.; Martz, D. et al.
Object Type: Article
System: The UNT Digital Library
R&D ERL: G5 test and commissioning plan (open access)

R&D ERL: G5 test and commissioning plan

Gun-to-5-cell cavity (G5) setup (Fig 1-2) can be considered as the first stage of the final BNL ERL design. The goal of the G5 setup is to test critical ERL components with the beam and characterize the beam produced by the gun. Also, this test will be used to assess effectiveness of the zigzag merger, which will be installed later in the ERL setup. The major components under the test will include the SRF gun, the five-cell SRF cavity, vacuum components, parts of the control and diagnostic systems. G5 is designed to measure the following beam parameters: (1) projected bunch emittance (?) and Twiss parameters ({alpha}, {beta}); (2) slice emittance; (3) bunch length; and (4) longitudinal and transverse halo.
Date: February 10, 2010
Creator: Kayran, D. & Pozdeyev, E.
Object Type: Report
System: The UNT Digital Library
Effect of Forging Strain Rate and Deformation Temperature on the Mechanical Properties of Warm-Worked 304L Stainless Steel (open access)

Effect of Forging Strain Rate and Deformation Temperature on the Mechanical Properties of Warm-Worked 304L Stainless Steel

Stainless steel 304L forgings were produced with four different types of production forging equipment – hydraulic press, mechanical press, screw press, and high-energy rate forging (HERF). Each machine imparted a different nominal strain rate during the deformation. The final forgings were done at the warm working (low hot working) temperatures of 816 ◦C, 843 ◦C, and 871 ◦C. The objectives of the study were to characterize and understand the effect of industrial strain rates (i.e. processing equipment), and deformation temperature on the mechanical properties for the final component. Some of the components were produced with an anneal prior to the final forging while others were deformed without the anneal. The results indicate that lower strain rates produced lower strength and higher ductility components, but the lower strain rate processes were more sensitive to deformation temperature variation and resulted in more within-part property variation. The highest strain rate process, HERF, resulted in slightly lower yield strength due to internal heating. Lower processing temperatures increased strength, decreased ductility but decreased within-part property variation. The anneal prior to the final forging produced a decrease in strength, a small increase in ductility, and a small decrease of within-part property variation.
Date: February 1, 2010
Creator: Switzner, Nathan T
Object Type: Article
System: The UNT Digital Library
ANALYSIS OF SAMPLES FROM TANK 6F CHEMICAL CLEANING (open access)

ANALYSIS OF SAMPLES FROM TANK 6F CHEMICAL CLEANING

Savannah River Remediation (SRR) is preparing Tank 6F for closure. The first step in preparing the tank for closure is mechanical sludge removal. In mechanical sludge removal, personnel add liquid (e.g., inhibited water or supernate salt solution) to the tank to form a slurry. They mix the liquid and sludge with pumps, and transfer the slurry to another tank for further processing. Mechanical sludge removal effectively removes the bulk of the sludge from a tank, but is not able to remove all of the sludge. In Tank 6F, SRR estimated a sludge heel of 5,984 gallons remained after mechanical sludge removal. To remove this sludge heel, SRR performed chemical cleaning. The chemical cleaning included two oxalic acid strikes, a spray wash, and a water wash. SRR conducted the first oxalic acid strike as follows. Personnel added 110,830 gallons of 8 wt % oxalic acid to Tank 6F and mixed the contents of Tank 6F with two submersible mixer pumps (SMPs) for approximately four days. Following the mixing, they transferred 115,903 gallons of Tank 6F material to Tank 7F. The SMPs were operating when the transfer started and were shut down approximately five hours after the transfer started. SRR collected a …
Date: February 2, 2010
Creator: Poirier, M. & Fink, S.
Object Type: Report
System: The UNT Digital Library
Extension of the Southern Hemisphere Atmospheric Radiocarbon Curve, 2120-850 years BP: Results from Tasmanian Huon Pine (open access)

Extension of the Southern Hemisphere Atmospheric Radiocarbon Curve, 2120-850 years BP: Results from Tasmanian Huon Pine

Decadal samples of dendrochronologically-dated pine (Lagorostrobos franklinii) from the Stanley River basin, Tasmania have been radiocarbon dated between 2120-850 yr BP. This data set overlaps and extends the current Southern Hemisphere record, which currently covers the period 110-995 yr BP. There is good agreement between the two records between 995-850 yr BP, between sample replicates and with consensus values for standards. As in the younger dataset, we find evidence for a distinct but variable offset between the southern hemisphere data and IntCal04; although this is likely due to real temporal variability in the interhemispheric offset, further work is planned to rule out possible laboratory or sample preparation differences.
Date: February 12, 2010
Creator: Zimmerman, S. R.; Guilderson, T. P.; Buckley, B. M. & Cook, E.
Object Type: Article
System: The UNT Digital Library