Design of an RF Antenna for a Large0Bore, High Power, Steady State Plasma Processing Chamber for Material Separation (open access)

Design of an RF Antenna for a Large0Bore, High Power, Steady State Plasma Processing Chamber for Material Separation

The purpose of this Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC, (Contractor), and Archimedes Technology Group, (Participant) is to evaluate the design of an RF antenna for a large-bore, high power, steady state plasma processing chamber for material separation. Criteria for optimization will be to maximize the power deposition in the plasma while operating at acceptable voltages and currents in the antenna structure. The project objectives are to evaluate the design of an RF antenna for a large-bore, high power, steady state plasma processing chamber for material separation. Criteria for optimization will be to maximize the power deposition in the plasma while operating at acceptable voltages and currents in the antenna structure.
Date: November 7, 2001
Creator: Rasmussen, D.A. & Freeman, R.L.
Object Type: Report
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
25 Can Verification Report for the LLNL Plutonium Packaging System (PuPS) (open access)

25 Can Verification Report for the LLNL Plutonium Packaging System (PuPS)

This document reports the results of the 25 Can Verification Run. The 25 Can Verification Run was performed as outlined in Section 1.d of SRS Acceptance Criteria (Reference 1). The run was performed over the period of February 16 to the 28, 2001. Each of these cans was welded with a dummy Inner Can containing about 5 kg of surrogate material. The cans were then analyzed using radiography and metallography of samples taken at four locations of the weld. The radiographs were examined for porosity. The micrographs of the metallurgical samples were examined for porosity, cracks, and lack of fusion. The results were reviewed by Derrill Rikard (a level 3 inspector at LLNL) and by Ken Durland (a level 3 inspector from WSRC). These reviews did not find anything of concern. Therefore we are submitting these results to SRS for concurrence.
Date: May 7, 2001
Creator: Riley, D C & Dodson, K E
Object Type: Report
System: The UNT Digital Library
Microbiologically-Facilitated Effects on the Surface Composition of Alloy 22, A Candidate Nuclear Waste Packaging Material (open access)

Microbiologically-Facilitated Effects on the Surface Composition of Alloy 22, A Candidate Nuclear Waste Packaging Material

The effects of microbiological activities on the surface composition of Alloy 22 was investigated. Prior studies suggesting microbially-generated selective dissolution of chromium from Alloy 22 were based solely on analyzing solubilized Alloy 22 elements. These and other investigations point to the insufficiencies of analyzing solubilized (or solubilized and reprecipitated) alloying elements to discern between homogeneous/stoichiometric dissolution and selective/non-stoichiometric dissolution of alloying elements. Therefore, an approach using X-ray Photoelectron Spectroscopy (XPS) to interrogate the surface layers of treated Alloy 22 specimens was taken to resolve this issue. Sputtering into the surface of the samples, coupled with XPS analysis at given intervals, allowed a high resolution quantitative elemental evaluation of the alloy as a function of depth. Biotically-incubated Alloy 22 show a region that could be depleted of chromium. Surfacial XPS analysis of these same coupons did not detect the presence of re-precipitated Alloy 22 component elements, also supporting the possible occurrence of non-stoichiometric dissolution. Thus, these preliminary data do not exclude the possibility of selective dissolution. It also appears that this experimental approach shows promise to unequivocally resolve this issue. Further tests using smoother-surface, more highly polished coupons should allow for better resolution between surface layers to permit a decisive determination …
Date: December 7, 2001
Creator: Horn, J; Lian, T & Martin, S I
Object Type: Article
System: The UNT Digital Library
Isentropic Compression of LX-04 on the Z Accelerator (open access)

Isentropic Compression of LX-04 on the Z Accelerator

Three sets of LX-04 samples of 0.18 and 0.49 mm nominal thicknesses were all dynamically loaded by Sandia's Z-accelerator with a ramp compression wave with a 200 ns rise time and about 150 kb peak stress. The LX-04/lithium fluoride samples interface velocities were measured using VISAR's. Comparisons of experimental and computational results are given. Compression and release isentropes both show some reaction and kinetic behavior of the LX-04. Experiments were also performed on fine-grained TATB. Future experiments on single crystals of HMX that are designed to measure the phase transition at high pressures is discussed.
Date: June 7, 2001
Creator: Reisman, D B; Forbes, J W; Tarver, C M; Garcia, F; Cauble, R C; Hall, C A et al.
Object Type: Article
System: The UNT Digital Library
Historical Time Line and Information About the Hanford Site (open access)

Historical Time Line and Information About the Hanford Site

Historical time line of the Hanford Site spanning from 1940 through 1997, including photographs and other information regarding the town sites and living conditions.
Date: March 7, 2001
Creator: Briggs, James D.
Object Type: Report
System: The UNT Digital Library
Hanford Radiological Protection Support Services Annual Report for 2000 (open access)

Hanford Radiological Protection Support Services Annual Report for 2000

During calendar year 2000, the Pacific Northwest National Laboratory performed its customary radiological protection support services in support of the U.S. Department of Energy Richland Operations Office and the Hanford contractors. These services included: 1) external dosimetry, 2) internal dosimetry, 3) in vivo monitoring, 4) radiological records, 5) instrument calibration and evaluation, and 6) calibration of radiation sources traceable to the National Institute of Standards and Technology. Each program summary describes the routine operations, program changes and improvements, program assessments, supporting technical studies, and professional activities.
Date: May 7, 2001
Creator: Lynch, Timothy P.; Bihl, Donald E.; Johnson, Michelle L.; Maclellan, Jay A. & Piper, Roman K.
Object Type: Report
System: The UNT Digital Library
A Constrained Standard Model: Effects of Fayet-Iliopoulos Terms (open access)

A Constrained Standard Model: Effects of Fayet-Iliopoulos Terms

In [1]the one Higgs doublet standard model was obtained by an orbifold projection of a 5D supersymmetric theory in an essentially unique way, resulting in a prediction for the Higgs mass m_H = 127 +- 8 GeV and for the compactification scale 1/R = 370 +- 70 GeV. The dominant one loop contribution to the Higgs potential was found to be finite, while the above uncertainties arose from quadratically divergent brane Z factors and from other higher loop contributions. In [3], a quadratically divergent Fayet-Iliopoulos term was found at one loop in this theory. We show that the resulting uncertainties in the predictions for the Higgs boson mass and the compactification scale are small, about 25percent of the uncertainties quoted above, and hence do not affect the original predictions. However, a tree level brane Fayet-Iliopoulos term could, if large enough, modify these predictions, especially for 1/R.
Date: October 7, 2001
Creator: Barbieri, Riccardo; Hall, Lawrence J. & Nomura, Yasunori
Object Type: Article
System: The UNT Digital Library
Prospects for the Simultaneous Operation of the Tevatron Collider and pp Experiments in the Antiproton Source Accumulator (open access)

Prospects for the Simultaneous Operation of the Tevatron Collider and pp Experiments in the Antiproton Source Accumulator

This document is a slightly expanded version of a portion of the Proton Driver design report. The Proton Driver group gets the credit for the original idea of running an Accumulator experiment in the BTeV era. The work presented here is a study of the feasibility of this idea. The addition of the Recycler Ring to the Fermilab accelerator complex provides an opportunity to continue the program of {bar p}p physics in the Antiproton Source Accumulator that was started by Fermilab experiments E760 and E835. The operational scenario presented here utilizes the Recycler Ring as an antiproton bank from which the colliders makes 'withdrawals' as needed to maintain the required luminosity in the Tevatron. The Accumulator is only needed to re-supply the bank in between withdrawals. When the {anti p} stacking rate is sufficiently high, and the luminosity requirements of the Collider experiments are sufficiently low, there will be time between Collider fills and subsequent refilling of the recycler to deliver beam to an experiment in the Accumulator. In the scenario envisioned here, the impact of the Accumulator experiment on the luminosity delivered to the Collider experiments is very small. If the Run II antiproton stacking rate goals are met, …
Date: June 7, 2001
Creator: Werkema, Steven J.
Object Type: Report
System: The UNT Digital Library
STRONTIUM ISOTOPE EVOLUTION OF PORE WATER AND CALCITE IN THE TOPOPAH SPRING TUFF, YUCCA MOUNTAIN , NEVADA (open access)

STRONTIUM ISOTOPE EVOLUTION OF PORE WATER AND CALCITE IN THE TOPOPAH SPRING TUFF, YUCCA MOUNTAIN , NEVADA

Yucca Mountain, a ridge of Miocene volcanic rocks in southwest Nevada, is being characterized as a site for a potential high-level radioactive waste repository. One issue of concern for the future performance of the potential repository is the movement of water in and around the potential repository horizon. Past water movement in this unsaturated zone is indicated by fluid inclusions trapped in calcite coatings on fracture footwall surfaces and in some lithophysal cavities. Some of the fluid inclusions have homogenization temperatures above the present-day geotherm (J.F. Whelan, written communication), so determining the ages of the calcite associated with those fluid inclusions is important in understanding the thermal history of the potential repository site. Calcite ages have been constrained by uranium-lead dating of silica polymorphs (opal and chalcedony) that are present in most coatings. The opal and chalcedony ages indicate that deposition of the calcite and opal coatings in the welded part of the Topopah Spring Tuff (TSw hydrogeologic unit) spanned nearly the entire history of the 12.8-million-year-old rock mass at fairly uniform overall long-term rates of deposition (within a factor of five). Constraining the age of a layer of calcite associated with specific fluid inclusions is complicated. Calcite is commonly …
Date: February 7, 2001
Creator: Marshall, B.D. & Futa, K.
Object Type: Report
System: The UNT Digital Library
Impedance studies of the thin film LiMn2O4/electrolyteinterface (open access)

Impedance studies of the thin film LiMn2O4/electrolyteinterface

Room-temperature impedance measurements of a thin-film LiMn2O4/LiPF6-EC-DMC interface have been used to identify the spontaneous formation Li2Mn2O4 at the interface at room temperature at voltages of 3.7 and higher. The impedance of the LiMn2O4 films exhibited two time constants: at about 14 kHz and 60 to 200 Hz. The high frequency loop is dependent on film morphology and was attributed to the substrate/oxide interface. The low frequency behavior was dependent on both state-of-charge (SOC) and time at a given SOC. At full charge the impedance in this electrolyte was stable at room temperature over several days. At high lithium contents, film OCV and impedance tended to grow logarithmically with time, with lower rates for lower Mn3+ content in the film. The increased impedance was removed by oxidation of the film to 4.5V vs. Li/Li+. The observations are consistent with a reversible disproportionation of part of the LiMn2O4 into Li2Mn2O4 and a lithium-deficient spinel. With extended constant current cycling part of the Li2Mn2O4 degrades to the Mn2O3 and the process is no longer reversible.
Date: April 7, 2001
Creator: Striebel, Kathryn A.; Sakai, E. & Cairns, Elton J.
Object Type: Article
System: The UNT Digital Library
An energy efficiency guide for use in cleanroom programming (open access)

An energy efficiency guide for use in cleanroom programming

This guide was developed to provide ideas for considering energy efficiency in the early stages of a cleanroom design project. Use of this guide will facilitate selection of design features that will improve energy efficiency in cleanrooms. Cleanroom owners and designers can use the guide to focus on energy intensive items in the design of a cleanroom facility.
Date: December 7, 2001
Creator: Tschudi, Bill; Xu, Tengfang & Sartor, Dale
Object Type: Report
System: The UNT Digital Library
Association of ventilation system type with SBS symptoms in office workers (open access)

Association of ventilation system type with SBS symptoms in office workers

This paper provides a review and synthesis of current knowledge about the associations of ventilation system types in office buildings with sick building syndrome symptoms and discusses potential explanations for the associations. Relative to natural ventilation, air conditioning, with or without humidification, was consistently associated with a statistically significant increase in the prevalence of one or more SBS symptoms. Prevalences were typically higher by approximately 30% to 200% in the air conditioned buildings. In two of three assessments from a single study, symptom prevalences were also significantly higher in air conditioned buildings than in buildings with simple mechanical ventilation and no humidification. In approximately half of assessments, SBS symptom prevalences were significantly higher in buildings with simple mechanical ventilation than in buildings with natural ventilation. Insufficient information was available for conclusions about the potential increased risk of SBS symptoms with humidification. The statistically significant associations of mechanical ventilation and air conditioning with SBS symptoms are much more frequent than expected from chance and also not likely to be a consequence of confounding by several potential personal, job, or building related confounders. The reasons for the increases in symptom prevalences with mechanical ventilation and particularly with air conditioning remain unclear. Multiple …
Date: February 7, 2001
Creator: Seppanen, Olli & Fisk, William J.
Object Type: Article
System: The UNT Digital Library
Intermetallic Alloys: Patterns and Complexity. Final Technical Report (open access)

Intermetallic Alloys: Patterns and Complexity. Final Technical Report

This report summarizes the research accomplishment of the P.I. and her collaborators. The major findings are (a) in the area of ordering in metallic alloys, the interplay between chemical and structural short-range order and (b) in the area of glassy dynamics in frustrated spin models. In the context of alloys, the development of a theoretical framework for incorporating the correlation between chemical and structural degrees of freedom has been a major accomplishment. The work on frustrated spin models has had a major impact on the understanding of the glass transition.
Date: November 7, 2001
Creator: Chakraborty, Bulbul
Object Type: Report
System: The UNT Digital Library
Bipartite graph partitioning and data clustering (open access)

Bipartite graph partitioning and data clustering

Many data types arising from data mining applications can be modeled as bipartite graphs, examples include terms and documents in a text corpus, customers and purchasing items in market basket analysis and reviewers and movies in a movie recommender system. In this paper, the authors propose a new data clustering method based on partitioning the underlying biopartite graph. The partition is constructed by minimizing a normalized sum of edge weights between unmatched pairs of vertices of the bipartite graph. They show that an approximate solution to the minimization problem can be obtained by computing a partial singular value decomposition (SVD) of the associated edge weight matrix of the bipartite graph. They point out the connection of their clustering algorithm to correspondence analysis used in multivariate analysis. They also briefly discuss the issue of assigning data objects to multiple clusters. In the experimental results, they apply their clustering algorithm to the problem of document clustering to illustrate its effectiveness and efficiency.
Date: May 7, 2001
Creator: Zha, Hongyuan; He, Xiaofeng; Ding, Chris; Gu, Ming & Simon, Horst D.
Object Type: Report
System: The UNT Digital Library
Kinetic Testing of Nitrate-Based Sodalite Formation Over the Temperature Range of 40 to 100 Degrees Centigrade (Final Report) (open access)

Kinetic Testing of Nitrate-Based Sodalite Formation Over the Temperature Range of 40 to 100 Degrees Centigrade (Final Report)

The focus of this study was the desilication kinetics of a Savannah River Site (SRS) tank farm 2H simulant over the temperature range of 40 to 100 C. Results showed that the formation of nitrate-nitrite-based sodalite over aluminum-to-silicon (Al:Si) molar ratios ranging from 1:1 to 20:1 exhibited overall-second order kinetics. The Arrhenius apparent activation energy associated with the crystal growth process of the sodalite was determined to be 35 kJ/mol over the temperature range investigated. Second-order rate constants were extrapolated to the 2H evaporator working temperature of {approx} 130 C and were found to be 0.012 L mol{sup -1} s{sup -1}. At this operating temperature, the half-life of a limiting reactant with a 0.1 M feed would be 14 min.
Date: September 7, 2001
Creator: Mattus, A. J.
Object Type: Report
System: The UNT Digital Library
INCREASING HEAVY OIL RESERVES IN THE WILMINGTON OIL FIELD THROUGH ADVANCED RESERVOIR CHARACTERIZATION AND THERMAL PRODUCTION TECHNOLOGIES (open access)

INCREASING HEAVY OIL RESERVES IN THE WILMINGTON OIL FIELD THROUGH ADVANCED RESERVOIR CHARACTERIZATION AND THERMAL PRODUCTION TECHNOLOGIES

The project involves using advanced reservoir characterization and thermal production technologies to improve thermal recovery techniques and lower operating and capital costs in a slope and basin clastic (SBC) reservoir in the Wilmington field, Los Angeles Co., CA. Through September 2000, project work has been completed on the following activities: data preparation; basic reservoir engineering; developing a deterministic three dimensional (3-D) geologic model, a 3-D deterministic reservoir simulation model and a rock-log model; well drilling and completions; and surface facilities on the Fault Block II-A Tar Zone (Tar II-A). Work is continuing on improving core analysis techniques, final reservoir tracer work, operational work and research studies to prevent thermal-related formation compaction in the Tar II-A steamflood area, and operational work on the Tar V steamflood pilot and Tar II-A post steamflood projects. Work was discontinued on the stochastic geologic model and developing a 3-D stochastic thermal reservoir simulation model of the Tar II-A Zone so the project team could use the 3-D deterministic reservoir simulation model to provide alternatives for the Tar II-A post steamflood operations and shale compaction studies. The project team spent the fourth quarter 2000 performing well work and reservoir surveillance on the Tar II-A post-steamflood project …
Date: May 7, 2001
Creator: Hara, Scott
Object Type: Report
System: The UNT Digital Library
Hybrid Chirped Pulse Amplification (open access)

Hybrid Chirped Pulse Amplification

A hybrid terawatt-amplification scheme combining optical-parametric-chirped-pulse amplification and amplification in active laser media is demonstrated for the first time. This simple technique uses a single pump pulse and eliminates gain narrowing, allows efficient energy conversion and does not require electro-optic devices.
Date: November 7, 2001
Creator: Jovanovic, I. & Barty, C.
Object Type: Article
System: The UNT Digital Library
River Protection Project (RPP) Project Management Plan (open access)

River Protection Project (RPP) Project Management Plan

The Office of River Protection (ORP) Project Management Plan (PMP) for the River Protection Project (RPP) describes the process for developing and operating a Waste Treatment Complex (WTC) to clean up Hanford Site tank waste. The Plan describes the scope of the project, the institutional setting within which the project must be completed, and the management processes and structure planned for implementation. The Plan is written from the perspective of the ORP as the taxpayers' representative. The Hanford Site, in southeastern Washington State, has one of the largest concentrations of radioactive waste in the world, as a result of producing plutonium for national defense for more than 40 years. Approximately 53 million gallons of waste stored in 177 aging underground tanks represent major environmental, social, and political challenges for the U.S. Department of Energy (DOE). These challenges require numerous interfaces with state and federal environmental officials, Tribal Nations, stakeholders, Congress, and the US Department of Energy-Headquarters (DOE-HQ). The cleanup of the Site's tank waste is a national issue with the potential for environmental and economic impacts to the region and the nation.
Date: March 7, 2001
Creator: NAVARRO, J.E.
Object Type: Report
System: The UNT Digital Library
Web document clustering using hyperlink structures (open access)

Web document clustering using hyperlink structures

With the exponential growth of information on the World Wide Web there is great demand for developing efficient and effective methods for organizing and retrieving the information available. Document clustering plays an important role in information retrieval and taxonomy management for the World Wide Web and remains an interesting and challenging problem in the field of web computing. In this paper we consider document clustering methods exploring textual information hyperlink structure and co-citation relations. In particular we apply the normalized cut clustering method developed in computer vision to the task of hyperdocument clustering. We also explore some theoretical connections of the normalized-cut method to K-means method. We then experiment with normalized-cut method in the context of clustering query result sets for web search engines.
Date: May 7, 2001
Creator: He, Xiaofeng; Zha, Hongyuan; Ding, Chris H.Q & Simon, Horst D.
Object Type: Report
System: The UNT Digital Library
Final report for Grant DE-FG02-84ER45131 (open access)

Final report for Grant DE-FG02-84ER45131

This Final Report surveys the work done on understanding the properties and behavior of driven interfaces. It is presented under two topics: (1) interfaces driven in pure and perturbed Hele-Shaw cells; (2) gels, colloids, and polymer solutions as complex media for interface growth and motion. This work has contributed to the international effort to learn about nonlinear and pattern forming systems. The data have been influential as theoretical and computational groups have attempted to understand the dynamics and nonlinear processing steps and the structure-property relations of complex materials. The Hele-Shaw cell was especially productive during this period of intense interest in ''simple'' nonlinear pattern formation, providing the simplest and best understood pattern forming system which could then be complicated with changes of boundary condition or changes of fluid property to test in a controlled way the effect on pattern formation of added physical/mathematical complexity.
Date: June 7, 2001
Creator: Maher, James V.
Object Type: Report
System: The UNT Digital Library
Comparison of chiller models for use in model-based fault detection (open access)

Comparison of chiller models for use in model-based fault detection

Selecting the model is an important and essential step in model based fault detection and diagnosis (FDD). Factors that are considered in evaluating a model include accuracy, training data requirements, calibration effort, generality, and computational requirements. The objective of this study was to evaluate different modeling approaches for their applicability to model based FDD of vapor compression chillers. Three different models were studied: the Gordon and Ng Universal Chiller model (2nd generation) and a modified version of the ASHRAE Primary Toolkit model, which are both based on first principles, and the DOE-2 chiller model, as implemented in CoolTools{trademark}, which is empirical. The models were compared in terms of their ability to reproduce the observed performance of an older, centrifugal chiller operating in a commercial office building and a newer centrifugal chiller in a laboratory. All three models displayed similar levels of accuracy. Of the first principles models, the Gordon-Ng model has the advantage of being linear in the parameters, which allows more robust parameter estimation methods to be used and facilitates estimation of the uncertainty in the parameter values. The ASHRAE Toolkit Model may have advantages when refrigerant temperature measurements are also available. The DOE-2 model can be expected to …
Date: June 7, 2001
Creator: Sreedharan, Priya & Haves, Philip
Object Type: Article
System: The UNT Digital Library
Study of Second Phase Particles and Fe content in Zr Alloys Using the Advanced Photon Source at Argonne (open access)

Study of Second Phase Particles and Fe content in Zr Alloys Using the Advanced Photon Source at Argonne

We have conducted a study of second phase particles and matrix alloying element concentrations in zirconium alloys using synchrotron radiation from the Advanced Photon Source (APS) at Argonne National Laboratory. The high flux of synchrotron radiation delivered at the 2BM beamline compared to conventional x-ray generators, enables the detection of very small precipitate volume fractions. We detected the standard C14 hcp Zr(Cr,Fe)2 precipitates, (the stable second phase in Zircaloy-4) in the bulk material at a cumulative annealing parameter as low as 10-20 h, and we followed the kinetics of precipitation and growth as a function of the cumulative annealing parameter (CAP) in the range 10-22 (quench) to 10-16 h. In addition, the unique combination of spatial resolution and elemental sensitivity of the 2ID-D/E microbeam line at the Advanced Photon Source at Argonne (APS) allows study of the alloying element concentrations at ppm levels in an area as small as 0.2 mm. We used x-ray fluorescence induced by this sub-micron x-ray beam to determine the concentration of these alloying elements in the matrix as a function of alloy type and thermal history. We discuss these results and the potential of synchrotron radiation-based techniques for studying zirconium alloys.
Date: November 7, 2001
Creator: Motta, Arthur T.
Object Type: Report
System: The UNT Digital Library
Isentropic Compression of LX-04 on the Z Accelerator (open access)

Isentropic Compression of LX-04 on the Z Accelerator

Three sets of LX-04 samples of 0.18 and 0.49 mm nominal thicknesses were all dynamically loaded by Sandia's Z-accelerator with a ramp compression wave with a 200 ns rise time and about 150 kb peak stress. The LX-04/lithium fluoride samples interface velocities were measured using VISAR's. Comparisons of experimental and computational results will be given. Compression and release isentropes both show some reaction and kinetic behavior of the LX-04. Experiments were also performed on fine-grained TATB. Future experiments on single crystals of HMX that are designed to measure the phase transition at high pressures will be discussed.
Date: June 7, 2001
Creator: Reisman, D. B.; Forbes, J. W.; Tarver, C. M.; Garcia, F.; Cauble, R. C.; Hall, C. A. et al.
Object Type: Article
System: The UNT Digital Library