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Technologies and tools for high-performance distributed computing. Final report

Description: In this project we studied the practical use of the MPI message-passing interface in advanced distributed computing environments. We built on the existing software infrastructure provided by the Globus Toolkit{trademark}, the MPICH portable implementation of MPI, and the MPICH-G integration of MPICH with Globus. As a result of this project we have replaced MPICH-G with its successor MPICH-G2, which is also an integration of MPICH with Globus. MPICH-G2 delivers significant improvements in message passing performance when compared to its predecessor MPICH-G and was based on superior software design principles resulting in a software base that was much easier to make the functional extensions and improvements we did. Using Globus services we replaced the default implementation of MPI's collective operations in MPICH-G2 with more efficient multilevel topology-aware collective operations which, in turn, led to the development of a new timing methodology for broadcasts [8]. MPICH-G2 was extended to include client/server functionality from the MPI-2 standard [23] to facilitate remote visualization applications and, through the use of MPI idioms, MPICH-G2 provided application-level control of quality-of-service parameters as well as application-level discovery of underlying Grid-topology information. Finally, MPICH-G2 was successfully used in a number of applications including an award-winning record-setting computation in numerical relativity. In the sections that follow we describe in detail the accomplishments of this project, we present experimental results quantifying the performance improvements, and conclude with a discussion of our applications experiences. This project resulted in a significant increase in the utility of MPICH-G2.
Date: May 1, 2000
Creator: Karonis, Nicholas T.
Partner: UNT Libraries Government Documents Department

A User's Manual for MASH V1.5 - A Monte Carlo Adjoint Shielding Code System

Description: The Monte Carlo ~djoint ~ielding Code System, MASH, calculates neutron and gamma- ray environments and radiation protection factors for armored military vehicles, structures, trenches, and other shielding configurations by coupling a forward discrete ordinates air- over-ground transport calculation with an adjoint Monte Carlo treatment of the shielding geometry. Efficiency and optimum use of computer time are emphasized. The code system includes the GRTUNCL and DORT codes for air-over-ground transport calculations, the MORSE code with the GIFT5 combinatorial geometry package for adjoint shielding calculations, and several peripheral codes that perform the required data preparations, transformations, and coupling functions. The current version, MASH v 1.5, is the successor to the original MASH v 1.0 code system initially developed at Oak Ridge National Laboratory (ORNL). The discrete ordinates calculation determines the fluence on a coupling surface surrounding the shielding geometry due to an external neutron/gamma-ray source. The Monte Carlo calculation determines the effectiveness of the fluence at that surface in causing a response in a detector within the shielding geometry, i.e., the "dose importance" of the coupling surface fluence. A coupling code folds the fluence together with the dose importance, giving the desired dose response. The coupling code can determine the dose response as a function of the shielding geometry orientation relative to the source, distance from the source, and energy response of the detector. This user's manual includes a short description of each code, the input required to execute the code along with some helpful input data notes, and a representative sample problem.
Date: October 1998
Creator: Slater, C. O.; Barnes, J. M.; Johnson, J. O. & Drischler, J. D.
Partner: UNT Libraries Government Documents Department

Status of the MCNP{trademark}/LCS{trademark} merger project

Description: The MCNPX code is now in limited release in a beta-test version. We provide a brief status report on the physics modules now in the code and of the enhanced capabilities to use new evaluated neutron data. We also present new benchmark calculations in which LAHET and MCNPX are compared with experimental results from the Japan Atomic Energy Research Institute.
Date: April 19, 1998
Creator: Hughes, H.G.; Adams, K.J.; Chadwick, M.B.; Comly, J.C.; Frankle, S.C.; Hendricks, J.S. et al.
Partner: UNT Libraries Government Documents Department

Multipacting Simulation Study for 56 MHz Quarter Wave Resonator using 2D Code

Description: A beam excited 56 MHz Radio Frequency (RF) Niobium Quarter Wave Resonator (QWR) has been proposed to enhance RHIC beam luminosity and bunching. Being a RF cavity, multipacting is expected; therefore an extensive study was carried out with the Multipac 2.1 2D simulation code. The study revealed that multipacting occurs in various bands up to peak surface electric field 50 kV/m and is concentrated mostly above the beam gap and on the outer conductor. To suppress multipacting, a ripple structure was introduced to the outer conductor and the phenomenon was successfully eliminated from the cavity.
Date: January 2, 2009
Creator: Naik,D. & Ben-Zvi, I.
Partner: UNT Libraries Government Documents Department

Geometric optimization of the 56 MHz SRF cavity and its frequency table

Description: It is essential to know the frequency of a Superconducting Radio Frequency (SRF) cavity at its 'just being fabricated' stage because frequency is the key parameter in constructing the cavity. In this paper, we report our work on assessing it. We can estimate the frequency change from stage to stage theoretically and/or by simulation. At the operating stage, the frequency can be calculated accurately, and, from this value, we obtain the frequencies at other stages. They are listed in a table that serves to check the processes from stage to stage. Equally important is optimizing the geometric shape of the SRF cavity so that the peak electric-field and peak magnetic-field are as low as possible. It is particularly desirable in the 56MHz SRF cavity of RHIC to maximize the frequency sensitivity of the slow tuner. After undertaking such optimization, our resultant peak electric-field is only 44.1MV/m, and the peak magnetic-field is 1049G at 2.5MV of voltage across the cavity gap. To quench superconductivity in an SRF cavity, it is reported that the limit of the peak magnetic-field is 1800G [1], and that of the peak electric-field is more than l00MV/m for a SRF cavity [2]. Our simulations employed the codes Superfish and Microwave Studio.
Date: October 1, 2008
Creator: Chang,X. & Ben-Zvi, I.
Partner: UNT Libraries Government Documents Department

Ming Parameter Input: Emma Model Redox Half Reaction Equation Deltag G Corrections for pH

Description: The purpose of this calculation is to provide appropriate input parameters for use in MING V 1.0 (CSCI 300 18 V 1.0). This calculation corrects the Grogan and McKinley (1990) values for {Delta}G so that the data will function in the MING model. The Grogan and McKinley (1990) {Delta}G data are presented for a pH of 12 whereas the MING model requires that the {Delta}G be reported at standard conditions (i.e. pH of 0).
Date: July 23, 1998
Creator: Jolley, D.M.
Partner: UNT Libraries Government Documents Department

Meta-transport library user`s guide

Description: Developing new transport protocols or protocol algorithms suffer from the complexity of the environment in which they are intended to run. Modeling techniques attempt to relieve this by simulating the environment. Our approach to promoting rapid prototyping of protocols and protocol algorithms is to provide a pre-built infrastructure that is common to all transport protocols, so that the focus is placed on the protocol-specific aspects. The Meta-Transport Library is a library of base classes that implement or abstract out the mundane functions of a protocol; new protocol implementations are derived from the base classes. The result is a fully viable transport protocol implementation, with emphasis on modularity. The collection of base classes form a {open_quotes}class-chest{close_quotes} of tools from which protocols can be developed and studied with as little change to a normal mix environment as possible. In addition to supporting protocol designers, this approach has pedagogical uses.
Date: July 1, 1996
Creator: Strayer, W.T.
Partner: UNT Libraries Government Documents Department

Direct calculation of leak path factors for highly compartmentalized buildings

Description: The large, highly compartmentalized configurations of buildings at many Department of Energy (DOE) facilities call the validity of traditional, simplistic methods for estimating contaminant leak path factors (LPFs) into question. Conversely, rigorous calculation of LPFs using detailed flow-field analysis computer codes is impractical for routine analysis. This paper describes a recent application of a rigorous, yet practical, method of calculating LPFs for the Chemical and Metallurgical Research (CMR) Facility at Los Alamos National Laboratory (LANL). The approach involves computer simulation of airborne contaminant transport using the MELCOR computer code. MELCOR is a general-purpose, fluid flow and aerosol transport analysis code originally developed by the US Nuclear Regulatory Commission to evaluate the release, transport, and deposition of radionuclides in nuclear reactor systems. However, the fundamental mathematical models in the code and the modular code architecture make it suitable to the CMR analysis.
Date: December 1, 1998
Creator: Leonard, M.T. & McClure, P.R.
Partner: UNT Libraries Government Documents Department

MESQUITE design : issues in the development of a mesh quality improvement toolkit.

Description: Poor mesh quality is known to adversely affect both solution efficiency and accuracy. There has been considerable research on a wide variety of mesh improvement algorithms, but the impact of these algorithms on applications has been limited because they are typically embedded in particular meshing software packages. To rectify this situation, they are developing a stand-alone mesh quality improvement toolkit called MESQUITE. In this paper, the authors describe the motivation, goals, and design of MESQUITE and give some computational results using the underlying algorithms that show the benefit of such a package.
Date: March 26, 2002
Creator: Freitag, L.; Leurent, T.; Knupp, P. & Melander, D.
Partner: UNT Libraries Government Documents Department

Longitudinal coupling impedance of a hole in an infinite plane screen

Description: An analytical formula for the longitudinal coupling impedance of a hole is developed using a variational method. We show that the coupling impedance can be expressed as a sum of functional series, whose argument is the dimensionless quantity kd alone, where k is the free-space wave number and d is the radius of the hole. When expanded in powers of kd, we recover the long wavelength result as a limiting case. The numerical evaluation reveals that the impedance can be well modeled by an RLC-resonator circuit. We also show the qualitatively good agreement between the theory and the MAFIA-T3 simulation for the geometry of a hole in a coupled waveguide with rectangular cross section.
Date: July 1, 1995
Creator: Chae, Yong-Chul
Partner: UNT Libraries Government Documents Department

Maganom Software User's Guide

Description: Maganom is a computer program for modeling magnetic data over 2-D structures. The program computes the magnetic anomalies across 2-D structures (models) to allow you to compare observed and computed magnetic data across the model structure. If a match between the computed and the observed magnetic values is unsatisfactory, you construct a new model and rerun Maganom to recalculate new magnetic values. In this way, you can continue calculations until you obtain a satisfactory match between the observed and the calculated values.
Date: March 11, 1999
Creator: Sharma, B.
Partner: UNT Libraries Government Documents Department

Review of the international conference on nuclear criticality-issues, discussions, and challenges

Description: The Fifth International Conference on Nuclear Criticality Safety (ICNC`95) was held September 17-22, 1995, in Albuquerque, New Mexico, USA. Organization and support for the conference was provided by the Sandia National Laboratories (SNL), Los Alamos National Laboratory (LANL), the University of New Mexico, and the Organization for Economic Cooperation and Development (OECD). This conference traces its history back to 1981 when a group of select criticality safety specialists (mostly experimentalists) from France, Germany, Japan, the United Kingdom, and the United States participated in a small conference at LANL in the United States. The motivation for the conference had been provided by Dr. J. C. Manaranche of France who had asked D. Smith and G. E. Whitesides of the United States if it would be possible for the French experimentalists to be able to visit the experimental facilities at LANL. This first conference was followed by a similar conference held in Dijon, France, in 1993. Then in 1987 the conference was hosted by the Japanese and opened to much wider participation by criticality safety specialists involved in experiments, methods development and analysis, and operations. With the 1987 conference in Japan and the fourth conference (ICNC`91) held in the United Kingdom, the interest and international participation by the criticality safety community has grown rapidly. With this background, the occasion of ICNC`95 was one of much expectation.
Date: December 31, 1995
Creator: Parks, C.V. & Whitesides, G.E.
Partner: UNT Libraries Government Documents Department

Implementation of the CEM-Code into the MCNPX-Code

Description: In the development stage of improving the physics abilities of MCNPX, the CEM code has been implemented into MCNPX as the nuclear reaction model for nuclei and pion induced reactions up to 5 GeV of kinetic energy. The CEM code includes all the reaction stages of intra:nuclear cascade, preequilibrium and equilibrium and is an alternative for the existing MCNPX models. The preliminary implementation fixes the uncompleted fission model of CEM by applying the RAL fission fragmentation model and provides a parameterized formula for the CEM input parameter a{sub f}/a{sub n}, the ratio of level density parameters at the fission saddle point shape and the compound shape of the excited nucleus. All the deficiencies are addressed in an improved CEM code that will replace the existing implementation when finished. Thick target calculations employing lead and tungsten targets have been performed to validate the implementation and test the CEM models against the old MCNPX models.
Date: September 13, 1998
Creator: Gallmeier, F.X.
Partner: UNT Libraries Government Documents Department

The use of MAVIS II to integrate the modeling and analysis of explosive valve interactions

Description: The MAVIS II computer program provides for the modeling and analysis of explosive valve interactions. This report describes the individual components of the program and how MAVIS II is used with other available tools to integrate the design and understanding of explosive valves. The rationale and model used for each valve interaction is described. Comparisons of the calculated results with available data have demonstrated the feasibility and accuracy of using MAVIS II for analytical studies of explosive valve interactions. The model used for the explosive or pyrotechnic used as the driving force in explosive valves is the most critical to be understood and modeled. MAVIS II is an advanced version that incorporates a plastic, as well as elastic, modeling of the deformations experienced when plungers are forced into a bore. The inclusion of a plastic model has greatly expanded the use of MAVIS for all categories (opening, closure, or combined) of valves, especially for the closure valves in which the sealing operation requires the plastic deformation of either a plunger or bore over a relatively large area. In order to increase its effectiveness, the use of MAVIS II should be integrated with the results from available experimental hardware. Test hardware such as the Velocity Interferometer System for Any Reflector (VISAR) and Velocity Generator test provide experimental data for accurate comparison of the actual valve functions. Variable Explosive Chamber (VEC) and Constant Explosive Volume (CEV) tests are used to provide the proper explosive equation-of-state for the MAVIS calculations of the explosive driving forces. The rationale and logistics of this integration is demonstrated through an example. A recent valve design is used to demonstrate how MAVIS II can be integrated with experimental tools to provide an understanding of the interactions in this valve.
Date: December 1998
Creator: Ng, R. & Kwon, D. M.
Partner: UNT Libraries Government Documents Department

Formation and sustainment of a very low aspect ratio tokamak using coaxial helicity injection (the Helicity Injected [HIT] experiment). Annual progress report No. 5, December 1, 1993--December 31, 1994

Description: This is the fifth Progress Report on the Helicity Injected Tokamak (HIT) at the University of Washington, Seattle, DOE Grant DE-FE06-90ER54095. This report covers the period of December 1, 1993 through December 31.
Date: February 6, 1995
Creator: Jarboe, T.R. & Nelson, B.A.
Partner: UNT Libraries Government Documents Department

MeshTV: scientific visualization and graphical analysis software

Description: The increasing data complexity engendered by the Accelerated Scientific Computing Initiative (ASCI) requires more capability in our scientific visualization software. B Division at Lawrence Livermore National Laboratory (LLNL) addresses these new and changing requirements with MeshTV. We began work on MeshTV around eight years ago, and have progressively refined the software to provide improved scientific analysis and visualization to well over 100 users at Liver-more, Los Alamos, Sandia, and in private industry. (U)
Date: February 8, 1999
Creator: Brugger, E S; Roberts, L & Wookey, S G
Partner: UNT Libraries Government Documents Department

MPDATA: A positive definite solver for geophysical flows

Description: This article is a review of MPDATA, a class of methods for the numerical simulation of advection based on the sign-preserving properties of upstream differencing. MPDATA was designed originally as an inexpensive alternative to flux-limited schemes for evaluating the transport of nonnegative thermodynamic variables (such as liquid water or water vapour) in atmospheric models. During the last decade, MPDATA has evolved from a simple advection scheme to a general approach for integrating the conservation laws of geophysical fluids on micro-to-planetary scales. The purpose of this paper is to summarize the basic concepts leading to a family of MPDATA schemes, review the existing MPDATA options, as well as to demonstrate the efficacy of the approach using diverse examples of complex geophysical flows.
Date: March 1, 1997
Creator: Smolarkiewicz, P.K. & Margolin, L.G.
Partner: UNT Libraries Government Documents Department

Simulation of PEP-II beam position monitors

Description: The authors use MAFIA to analyze the PEP-II button-type beam position monitors (BPMs). Employing proper termination of the BPM into a coaxial cable, the output signal at the BPM can be determined. Thus the issues of sensitivity and power output can be addressed quantitatively, including all transient effects and wakefields. Besides this first quantitative analysis of a true BPM 3D structure, they find that internal resonant modes are a major source of high value narrow-band impedances. These are evaluated and methods are presented to suppress these parasitic resonances below the tolerable limit of multibunch instabilities.
Date: May 1, 1995
Creator: Ng, C.K.; Weiland, T.; Martin, D.; Smith, S. & Kurita, N.
Partner: UNT Libraries Government Documents Department