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N = 2 string amplitudes

Description: In physics, solvable models have played very important roles. Understanding a simple model in detail teaches us a lot about more complicated models in generic situations. Five years ago, C. Vafa and I found that the closed N = 2 string theory, that is a string theory with the N = 2 local supersymmetry on the worldsheet, is classically equivalent to the self-dual Einstein gravity in four spacetime dimensions. Thus this string theory is solvable at the classical level. More recently, we have examined the N = 2 string partition function for spacial compactifications, and computed it to all order in the string perturbation expansion. The fact that such computation is possible at all suggests that the N = 2 string theory is solvable even quantum mechanically.
Date: August 1, 1995
Creator: Ooguri, H.

2 {times} 2 TeV {mu}{sup +}{mu}{sup {minus}} collider: Lattice and accelerator-detector interface study

Description: The design for a high-luminosity {mu}{sup +}{mu}{sup {minus}} superconducting storage ring is presented based on first-pass calculations. Special attention is paid to two Iowa interaction regions (IR) whose optics are literally interlaced with the collider detectors. Various sources of backgrounds in IR are explored via realistic Monte Carlo simulations. An improved design of the collider lattice in the neighborhood of the interaction points (EP) is determined by the need to reduce significantly background levels in the detectors.
Date: May 1, 1995
Creator: Gelfand, N.M. & Mokhov, N.V.

A 2 to 4 nm high power FEL on the SLAC linac

Description: We report the results of preliminary studies of a 2 to 4 nm SASE FEL, using a photoinjector to produce the electron beam, and the SLAC linac to accelerate it to an energy up to 10 GeV. Longitudinal bunch compression is used to increases ten fold the peak current to 2.5 kA, while reducing the bunch length to the subpicosecond range. The saturated output power is in the multi-gigawatt range, producing about 10{sup 14} coherent photons within a bandwidth of about 0.2% rms, in a pulse of several millijoules. At 120Hz repetition rate the average power is about 1 W. The system is optimized for x-ray microscopy in the water window around 2 to 4 nm, and will permit imaging a biological sample in a single subpicosecond pulse.
Date: September 1, 1992
Creator: Pellegrini, C.; Rosenzweig, J.; Nuhn, H. D.; Pianetta, P.; Tatchyn, R.; Winick, H. et al.

2 x 2 Polyethylene Reflected and Moderated Highly Enriched Uranium System with Rhenium

Description: The 2 × 2 array HEU-Re experiment was performed on the Planet universal critical assembly machine on November 4th, 2003 at the Los Alamos Critical Experiments Facility (LACEF) at Los Alamos National Laboratory (LANL). For this experiment, there were 10 ½ units, each full unit containing four HEU foils and two rhenium foils. The top unit contained only two HEU foils and two rhenium foils. A total of 42 HEU foils were used for this experiment. Rhenium is a desirable cladding material for space nuclear power applications. This experiment consisted of HEU foils interleaved with rhenium foils and is moderated and reflected by polyethylene plates. A unit consisted of a polyethylene plate, which has a recess for rhenium foils, and four HEU foils in a single layer in the top recess of each polyethylene plate. The Planet universal criticality assembly machine has been previously used in experiments containing HEU foils interspersed with SiO2 (HEU-MET-THERM-001), Al (HEU-MET-THERM-008), MgO (HEU-MET-THERM-009), Gd foils (HEU-MET-THERM-010), 2 × 2 × 26 Al (HEU-MET-THERM-012), Fe (HEU-MET-THERM-013 and HEU-MET-THERM-015), 2 × 2 × 23 SiO2 (HEU-MET-THERM-014), 2 × 2 × 11 hastalloy plates (HEU-MET-THERM-016), and concrete (HEU-MET-THERM-018). The 2 × 2 array of HEU-Re is considered acceptable for use as a benchmark critical experiment.
Date: September 1, 2010
Creator: Ellis, A. Nichole; Hutchinson, Jesson; Bess, John D.; Polyakov, Dmitry N.; Glushkov, Evgeny S. & Glushkov, Alexey E.

2 x 2 TeV mu(superscript +) mu (superscript) collider

Description: The scenarios for high-luminosity 2 x 2 TeV and 250 x 250 GeV {mu}{sup +}{mu}{sup -} colliders are presented. Having a high physics potential, such a machine has specific physics and technical advantages and disadvantages when compared with an e{sup +}e{sup -} collider. Parameters for the candidate designs and the basic components - proton source, pion production and decay channel, cooling, acceleration and collider storage ring - are considered. Attention is paid to the areas mostly affecting the collider performance: targetry, energy spread, superconducting magnet survival, detector backgrounds, polarization, environmental issues. 13 refs., 9 figs., 4 tabs.
Date: October 1, 1996
Creator: Mokhov, N.V. & Noble, R.J. Feed Processing and Handling DL2 Final Report

Description: This milestone report is the deliverable for our Feed Processing and Handling project. It includes results of wet biomass feedstock analysis, slurry pumping information, fungal processing to produce a lignin-rich biorefinery residue and two subcontracted efforts to quantify the amount of wet biomass feedstocks currently available within the corn processing and paper processing industries.
Date: September 30, 2006
Creator: Elliott, Douglas C.; Magnuson, Jon K. & Wend, Christopher F.

3,2-HOPO Complexes of Near-Infra-Red (NIR) Emitting Lanthanides: Sensitization of Ho(III) and Pr(III) in Aqueous Solution

Description: There is a growing interest in Near Infra-Red (NIR) emission originating from organic complexes of Ln{sup III} cations. As a major impetus, biological tissues are considerably more transparent at these low energy wavelengths when compared to visible radiation, which facilitates deeper penetration of incident and emitted light. Furthermore, the long luminescence lifetimes of Ln{sup III} complexes (eg. Yb{sup III}, {tau}{sub rad} {approx} 1 ms) when compared to typical organic molecules can be utilized to vastly improve signal to noise ratios by employing time-gating techniques. While the improved quantum yield of Yb{sub III} complexes when compared to other NIR emitters favors their use for bioimaging applications, there has also been significant interest in the sensitized emission from other 4f metals such as Ln = Nd, Ho, Pr and Er which have well recognized applications as solid state laser materials (eg. Nd {approx} 1.06 {micro}m, Ho {approx} 2.09 {micro}m), and in telecommunications (eg. Er {approx} 1.54 {micro}m) where they can be used for amplification of optical signals. As a result of their weak (Laporte forbidden) f-f absorptions, the direct excitation of Ln{sup III} cations is inefficient, and sensitization of the metal emission is more effectively achieved using the so-called antenna effect. We have previously examined the properties of several Eu{sup III} complexes which feature 1-hydroxypyridin-2-one (Fig. 1) as the light harvesting chromophore. While the 1,2-HOPO isomer was found to strongly sensitize Eu{sup III}, we noted the analogous Me-3,2-HOPO isomer does not, which prompted further investigation of the properties of this chromophore with other metals.
Date: May 19, 2008
Creator: Moore, Evan G.; Szigethy, Geza; Xu, Jide; Palsson, Lars-Olof; Beeby, Andrew & Raymond, Kenneth N.

A 3.3 MJ, Rb + 1 driver design based on an integrated systems analysis

Description: A computer model for systems analysis of heavy ion drivers has been developed and used to evaluate driver designs for inertial fusion energy (IFE). The present work examines a driver for a close-coupled target design that requires less total beam energy but also smaller beam spots sizes than previous target designs. Design parameters and a cost estimate for a 160 beam, 3.3 MJ driver using rubidium ions (A = 85) are reported, and the sensitivity of the results to variations in selected design parameters is given.
Date: March 7, 2000
Creator: Meier, W R; Barnard, J J & Bangerter, R O

A 3.3 MJ, Rb{sup +1} Driver Design Based on an Integrated Systems Analysis

Description: A computer model for systems analysis of heavy ion drivers has been developed and used to evaluate driver designs for inertial fusion energy (IFE). The present work examines a driver for a close-coupled target design that requires less total beam energy but also smaller beam spots sizes than previous target designs. Design parameters and a cost estimate for a 160 beam, 3.3 MJ driver using rubidium ions (A = 85) are reported, and the sensitivity of the results to variations in selected design parameters is given.
Date: September 15, 2000
Creator: Meier, W. R.; Barnard, J. J. & Bangerter, R. O.

3,4,3-LI(1,2-HOPO): In Vitro Formation of Highly Stable Lanthanide Complexes Translates into Efficacious In Vivo Europium Decorporation

Description: The spermine-based hydroxypyridonate octadentate chelator 3,4,3-LI(1,2-HOPO) was investigated for its ability to act as an antennae that sensitizes the emission of Sm{sup III}, Eu{sup III}, and Tb{sup III} in the Visible range (Φ{sub tot} = 0.2 - 7%) and the emission of Pr{sup III}, Nd{sup III}, Sm{sup III}, and Yb{sup III} in the Near Infra-Red range, with decay times varying from 1.78 μs to 805 μs at room temperature. The particular luminescence spectroscopic properties of these lanthanide complexes formed with 3,4,3-LI(1,2-HOPO) were used to characterize their respective solution thermodynamic stabilities as well as those of the corresponding La{sup III}, Gd{sup III}, Dy{sup III}, Ho{sup III}, Er{sup III}, Tm{sup III}, and Lu{sup III} complexes. The remarkably high affinity of 3,4,3-LI(1,2-HOPO) for lanthanide metal ions and the resulting high complex stabilities (pM values ranging from 17.2 for La{sup III} to 23.1 for Yb{sup III}) constitute a necessary but not sufficient criteria to consider this octadentate ligand an optimal candidate for in vivo metal decorporation. The in vivo lanthanide complex stability and decorporation capacity of the ligand were assessed, using the radioactive isotope {sup 152}Eu as a tracer in a rodent model, which provided a direct comparison with the in vitro thermodynamic results and demonstrated the great potential of 3,4,3-LI(1,2-HOPO) as a therapeutic metal chelating agent.
Date: July 13, 2011
Creator: Sturzbecher-Hoehne, Manuel; Ng Pak Leung, Clara; Daleo, Anthony; Kullgren, Birgitta; Prigent, Anne-Laure; Shuh, David K. et al.

3.9 GHz superconducting accelerating 9-cell cavity vertical test results

Description: The 3rd harmonic 3.9GHz accelerating cavity was proposed to improve the beam performance of the FLASH (TTF/DESY) facility [1]. In the frame of a collaborative agreement, Fermilab will provide DESY with a cryomodule containing a string of four cavities. In addition, a second cryomodule with one cavity will be fabricated for installation in the Fermilab photo-injector, which will be upgraded for the ILC accelerator test facility. The first 9-cell Nb cavities were tested in a vertical setup and they didn't reach the designed accelerating gradient [2]. The main problem was a multipactor in the HOM couplers, which lead to overheating and quenching of the HOM couplers. New HOM couplers with improved design are integrated in the next 9-cell cavities. In this paper we present all results of the vertical tests.
Date: June 1, 2007
Creator: Khabiboulline, Timergali; Cooper, Charles; Dhanaraj, Nandhini; Edwards, Helen; Foley, Mike; Harms, Elvin et al.

A 3-axis force balanced accelerometer using a single proof-mass

Description: This paper presents a new method for wideband force balancing a proof-mass in multiple axes simultaneously. Capacitive position sense and force feedback are accomplished using the same air-gap capacitors through time multiplexing. Proof of concept is experimentally demonstrated with a single-mass monolithic surface micromachined 3-axis accelerometer.
Date: April 1997
Creator: Lemkin, M.A.; Boser, B.E.; Auslander, D. & Smith, J.

3-D Cavern Enlargement Analyses

Description: Three-dimensional finite element analyses simulate the mechanical response of enlarging existing caverns at the Strategic Petroleum Reserve (SPR). The caverns are located in Gulf Coast salt domes and are enlarged by leaching during oil drawdowns as fresh water is injected to displace the crude oil from the caverns. The current criteria adopted by the SPR limits cavern usage to 5 drawdowns (leaches). As a base case, 5 leaches were modeled over a 25 year period to roughly double the volume of a 19 cavern field. Thirteen additional leaches where then simulated until caverns approached coalescence. The cavern field approximated the geometries and geologic properties found at the West Hackberry site. This enabled comparisons are data collected over nearly 20 years to analysis predictions. The analyses closely predicted the measured surface subsidence and cavern closure rates as inferred from historic well head pressures. This provided the necessary assurance that the model displacements, strains, and stresses are accurate. However, the cavern field has not yet experienced the large scale drawdowns being simulated. Should they occur in the future, code predictions should be validated with actual field behavior at that time. The simulations were performed using JAS3D, a three dimensional finite element analysis code for nonlinear quasi-static solids. The results examine the impacts of leaching and cavern workovers, where internal cavern pressures are reduced, on surface subsidence, well integrity, and cavern stability. The results suggest that the current limit of 5 oil drawdowns may be extended with some mitigative action required on the wells and later on to surface structure due to subsidence strains. The predicted stress state in the salt shows damage to start occurring after 15 drawdowns with significant failure occurring at the 16th drawdown, well beyond the current limit of 5 drawdowns.
Date: March 1, 2002

3-D Characterization of the Structure of Paper and Paperboard and Their Application to Optimize Drying and Water Removal Processes and End-Use Applications

Description: The three dimensional structure of paper materials plays a critical role in the paper manufacturing process especially via its impact on the transport properties for fluids. Dewatering of the wet web, pressing and drying will benefit from knowledge of the relationships between the web structure and its transport coefficients. The structure of the pore space within a paper sheet is imaged in serial sections using x-ray micro computed tomography. The three dimensional structure is reconstructed from these sections using digital image processing techniques. The structure is then analyzed by measuring traditional descriptors for the pore space such as specific surface area and porosity. A sequence of microtomographs was imaged at approximately 2 m intervals and the three-dimensional pore-fiber structure was reconstructed. The pore size distributions for both in-plane as well as transverse pores were measured. Significant differences in the in-plane (XY) and the transverse directions in pore characteristics are found and may help partly explain the different liquid and vapor transport properties in the in-plane and transverse directions. Results with varying sheet structures compare favorably with conventional mercury intrusion porosimetry data. Interestingly, the transverse pore structure appears to be more open with larger pore size distribution compared to the in plane pore structure. This may help explain the differences in liquid and vapor transport through the in plane and transverse structures during the paper manufacturing process and during end-use application. Comparison of Z-directional structural details of hand sheet and commercially made fine paper samples show a distinct difference in pore size distribution both in the in-plane and transverse direction. Method presented here may provide a useful tool to the papermaker to truly engineer the structure of paper and board tailored to specific end-use applications. The difference in surface structure between the top and bottom sides of the porous material, i.e. ...
Date: August 29, 2004
Creator: Shri Ramaswamy, University of Minnesota & B.V. Ramarao, State University of New York

3-D computer simulations of EM field sin the APS vacuum chamber. Part 2: Time-domain analysis

Description: Our simulations suggest that the strong peak around 4 GHz in the narrow gap observed in the measurements is generated by TE modes. Therefore, one should not worry about this peak insofar as the coupling impedance is concerned. On the other hand, some discrepancies between our simulations and the measurements are noticed and remain to be resolved.
Date: January 20, 1989
Creator: Chou, W.

3-D computer simulations of EM fields in the APS vacuum chamber: Part 1, Frequency-domain analysis

Description: The vacuum chamber proposed for the storage ring of the 7-GeV Advanced Photon Source (APS) basically consists of two parts: the beam chamber and the antechamber, connected to each other by a narrow gap. A sector of 1-meter-long chamber with dosed end plates, to which are attached the 1-inch-diameter beampipes centered at the beam chamber, has been built for experimental purposes. The 3-D code MAFIA has been used to simulate the frequency-domain behaviors of EM fields in this setup. The results are summarized in this note and are compared with that previously obtained from 2-D simulations and that from network analyzer measurements. They are in general agreement. A parallel analysis in the time-domain is reported in a separate note. The method of our simulations can be briefly described as follows. The 1-inch diameter beampipes are terminated by conducting walls at a length of 2 cm. The whole geometry can thus be considered as a cavity. The lowest RF modes of this geometry are computed using MAFIA. The eigenfrequencies of these modes are a direct output of the eigenvalue solver E3, whereas the type of each mode is determined by employing the postprocessor P3. The mesh sizes are chosen such that they are small enough for computations in the frequency region in which we are interested (the sampling theorem), while the total number of mesh points is still well within the range that our computer system can cope with.
Date: September 4, 1990
Creator: Chou, W. & Bridges, J.

3-D electromagnetic modeling of wakefields in accelerator components

Description: We discuss the use of 3-D finite-difference time-domain (FDTD) electromagnetic codes for modeling accelerator components. Computational modeling of cylindrically symmetric structures such as induction accelerator cells has been very successful in predicting the wake potential and wake impedances of these structures, but full 3-D modeling of complex structures has been limited due to substantial computer resources required for a full 3-D model. New massively parallel 3-D time domain electromagnetic codes now under development using conforming unstructured meshes allow a substantial increase in the geometric fidelity of the structures being modeled. Development of these new codes are discussed in context of applicability to accelerator problems. Various 3-D structures are tested with an existing cubical cell FDTD code and wake impedances compared with simple analytic models for the structures; results will be used as benchmarks for testing the new time time domain codes. Structures under consideration include a stripline beam position monitor as well as circular and elliptical apertures in circular waveguides. Excellent agreement for monopole and dipole impedances with models were found for these structures below the cutoff frequency of the beam line.
Date: September 18, 1996
Creator: Poole, B.R.; Caporaso, G.J.; Ng, Wang C.; Shang, C.C. & Steich, D.

3-D Experimental Fracture Analysis at High Temperature

Description: T*e, which is an elastic-plastic fracture parameter based on incremental theory of plasticity, was determined numerically and experimentally. The T*e integral of a tunneling crack in 2024-T3 aluminum, three point bend specimen was obtained through a hybrid analysis of moire interferometry and 3-D elastic-plastic finite element analysis. The results were verified by the good agreement between the experimentally and numerically determined T*e on the specimen surface.
Date: September 14, 2001
Creator: Jackson, John H. & Kobayashi, Albert S.

3-D field computation: The near-triumph of commerical codes

Description: In recent years, more and more of those who design and analyze magnets and other devices are using commercial codes rather than developing their own. This paper considers the commercial codes and the features available with them. Other recent trends with 3-D field computation include parallel computation and visualization methods such as virtual reality systems.
Date: July 1995
Creator: Turner, L. R.

3-D Finite Element Analyses of the Egan Cavern Field

Description: Three-dimensional finite element analyses were performed for the two gas-filled storage caverns at the Egan field, Jennings dome, Louisiana. The effects of cavern enlargement on surface subsidence, storage loss, and cavern stability were investigated. The finite element model simulated the leaching of caverns to 6 and 8 billion cubic feet (BCF) and examined their performance at various operating conditions. Operating pressures varied from 0.15 psi/ft to 0.9 psi/ft at the bottom of the lowest cemented casing. The analysis also examined the stability of the web or pillar of salt between the caverns under differential pressure loadings. The 50-year simulations were performed using JAC3D, a three dimensional finite element analysis code for nonlinear quasistatic solids. A damage criterion based on onset of dilatancy was used to evaluate cavern instability. Dilation results from the development of microfractures in salt and, hence, potential increases in permeability onset occurs well before large scale failure. The analyses predicted stable caverns throughout the 50-year period for the range of pressures investigated. Some localized salt damage was predicted near the bottom walls of the caverns if the caverns are operated at minimum pressure for long periods of time. Volumetric cavern closures over time due to creep were moderate to excessive depending on the salt creep properties and operating pressures. However, subsidence above the cavern field was small and should pose no problem, to surface facilities.
Date: February 1, 1999
Creator: Klamerus, E.W. & Ehgartner, B.L.