6/27/00 -- New NAS Tech Reports Online
Take a look at the two latest NAS Technical Reports detailing the division's research work.

A Public/Private Extension of Conway's Accessor Model, by Karen McCann and Maurice Yarrow, documents a new object-oriented model for a Perl package.

An Advanced User Interface Approach for Complex Parameter Study Process Specification on the Information Power Grid, by Yarrow, McCann, Rupak Biswas, and Rob Van der Wijngaart, details the authors' novel approach to the creation of parameter study suites.

6/20/00 -- NAS Researchers to Model DNA Electron Transport
Combining recent methods in quantum physics with biology, NAS scientists will use an innovative approach to develop models for electron flow in DNA. The research, conducted by M.P. Anantram, Chris Henze, and T.R. Govindan, is funded by a grant from the NASA Ames Director's Discretionary Fund totaling $80 thousand over two years. The team hopes to solve conflicting data from several other experiments.

Over the last decade, conflicting experimental results of DNA conductance have appeared, in large part due to the difficulty in measuring electron transport in DNA. The NAS team believes their approach -- applying computational modeling to DNA electron transport -- will help resolve experimental measurements. The team has already succeeded in modeling electron transport through molecules.

The new work is important to NASA missions in space, astrobiology, and information systems. Damage and changes in genes from radiation is of fundamental importance to NASA Computational Astrobiology Institute projects. Modeling the flow of electrons through DNA may lead to ways to control oxidative damage in DNA. Oxidative damage has been linked to gene mutation and cancer, and is central to long-term survival of humans in space.

A newly formed Revolutionary Computing project in the Intelligent Systems Program is investigating the potential for using DNA to build wires and circuits for future computers. Modeling electron flow through DNA junctions will also form the first steps to develop DNA-inspired electronic devices.

For more information, contact M.P. Anantram at anant@nas.nasa.gov, 650-604-1852.

6/13/00 -- Nanotechnology Team Recognized
Members of the Ames Integrated Product Team on Devices and Nanotechnology -- representing the largest nanotechnology research efforts within the federal government -- received a group achievement award for "excellence in research and outstanding contributions to the emerging field of nanotechnology" at the 2000 NASA Honor Awards ceremony on June 7.

Project manager Meyya Meyyappan, credits the NAS Systems Division as "the birthplace" of this work, originating with a small theory group doing computational nanotechnology at the NAS Facility. The team has expanded to include experimental research in the laboratory. Experiments on growing nanotubes for applications such as cancer diagnostics attract a steady stream of visitors from the high-tech arena, including former House science and technology committee chair Bob Walker, who toured the "nanotube garden" on June 6.

The nanotubes -- 1,000 times smaller than a human hair -- are used as tips on scanning tunneling microscopes, and may someday replace standard micromachined tungsten and silicon tips on experimental atomic force microscopes (ATM). The NASA team currently uses the nanotube tips to study dust particles on Mars. To illustrate the size of these tips -- which are not visible to the eye -- Ames researchers used a carbon nanotube tip in an ATM to write the White House "nano" website address; a demonstration of nanolithography done on a silicon wafer.

Among those receiving the group achievement award were NAS researchers M.P. Anantrim, Bryan Biegel, T.R. Govindan, Jie Han Cun-Zheng Ning, Deepak Srivastava, Alexei Svizhenko, and Toshishige Yamada. Visit the Devices and Nanotechnology website, or contact Meyya Meyyappan at meyya@orbit.arc.nasa.gov.

6/6/00 -- NAS Scientists Design Optically-Pumped Terahertz Laser
Scientists in NAS's Research Branch have designed a special quantum well structure and an optically-pumped terahertz laser for applications in NASA's Earth and Space Enterprises. The research, conducted by Cun-Zheng Ning and Ansheng Liu, is funded by a grant from the NASA Ames Director's Discretionary Fund totaling $80 thousand for two years. A patent application is in the works.

The proposed design will make miniaturization of optically-pumped terahertz lasers possible, opening the door to applications in earth system observation, far-infrared astronomical detection and measurement, and other commercial applications, such as medical and biochemical detection and sensing.

Highly efficient, high-powered, and compact radiation sources are needed such for applications. Existing sources based on electronic generation is limited in wavelength, efficiency, and power. Optoelectronic generation was proposed recently to drastically improve those aspects. But published research based on optically pumped terahertz generation use bulky CO2 lasers as pumping sources -- making the whole system too bulky and heavy for NASA applications.

Ning and Liu have investigated the possibility of using triple quantum well structures as active region of a terahertz laser. Results show that their proposed quantum well (QW) structures allow the widely available telecomm QW-lasers to be used as pumping, reducing the size from a bulky CO2 laser to a micrometer size of a diode laser. A paper detailing their findings appears in Applied Physics Letters (April 10, 2000). For more information, contact Cun-Zheng Ning at cning@nas.nasa.gov 650 604-3983

5/30/00 -- Chimera Grid Tools 1.3 Released
A new version of of the Chimera Grid Tools (CGT), a set of programs and scripts for generating overset grids, has just been released. Developed at NASA's Ames Research Center, CGT 1.3 includes: enhanced display options, new grid-induced truncation error analysis for 3-D volume grids, and an automated hole-cutting preprocessing module for use with the OVERFLOW-D flow solver.

CGT is widely used for solving complex computational fluid dynamics (CFD) problems in a variety of real-world applications, including launch and re-entry vehicles, rotorcraft, ships, submarines, and sailboats. The package includes a graphical user interface called OVERGRID to generate grid systems. Read more about Chimera Grid Tools 1.3, or contact CGT co-developer Stuart Rogers in the NAS Systems Division at rogers@nas.nasa.gov, 650-604-4481.

5/23/00 -- NAS Assists First FutureFlight Central Exercise
FutureFlight Central, a unique facility that simulates real-time air traffic control tower situations, received assistance from the NAS Systems Division in recording the facility's first customer simulation exercise. Michael Boswell, in the NAS publications and media group, captured on videotape both the action in the simulator and human responses during the exercise. By analyzing the videotapes of how pilots, controllers, and airport personnel react in unexpected circumstances, experts can improve procedures that will save lives.

For three days in late April, Boswell, acting as director, cameraman, and editor, recorded all activities in the simulator and edited "live" rough cuts to capture the best visual scenes of each simulation, He also documented highlights of each simulation, and created a new template for identifying the best camera angles for each scenario.

FutureFlight Central is a full-scale airport operations simulator used for testing new technologies and improving operating procedures. The facility features 12 screens that create a seamless, 360-degree view of realistic airport traffic conditions. In one simulation, for example, an aircraft taxies onto a runway where another aircraft is just landing. In another, an aircraft moving onto the runway encounters debris that could damage the aircraft. For more information, contact Nancy Dorighi, operations manager, at ndorighi@mail.arc.nasa.gov.

5/16/00 -- New Issue of Gridpoints Online
Check out the Spring 2000 issue of Gridpoints, the NAS Systems Division's quarterly magazine. Preview the table of contents, or just download the PDF file. You can also subscribe to receive the print version.

5/16/00 -- NAS Researcher Chairs Nanotubes Conference
Nanotechnology researcher Deepak Srivastava chaired, "Carbon Nanotubes: Advances in Cutting Edge Applications and Scalable Production," April 10-11 in Miami. Srivastava gave an invited talk on plasticity and hyrogen diffusion on C and BN nanotubes. Speakers from industry, government labs, and universities emphasized commercial aspects of many proposed applications in nanophase composite materials, supercapacitors, energy and gas storage, fuel cells, nanoelectronics, field emmission displays areas.

Srivastava gave an invited on plasticity and hydrogen diffusion on C and BN nanotubes, and an Ames' experimental nanotechnology researcher Dr. Allen Cassel discussed nanotube applications in nanoelectronic circuitery and combinatorial chemical approaches for tuning the production of nanotubes on different substrates.Srivastava also presented "Nanotechnology of Molecular Materials, Electronics, and Machines: Carbon Nanotubes" at the University of Florida, Gainesville. For more information, contact Srivastava at deepak@nas.nasa.gov

5/09/00 -- Protein-folding Code Hums With NAS Optimization
A scientific code used to simulate protein folding sequences now performs 36 times faster than was previously possible, thanks to code optimizations made by NAS Systems Division researcher James Taft. The code, called COSMOS, is a molecular dynamics model used in NASA's astrobiology research.

Taft modified the code to utilize 343 processors on Lomax, a parallel processor SGI Origin 2800 located at the NAS Facility. With 512 CPUs, Lomax is currently the largest single, shared-memory multiprocessor system in the world. Using a shared-memory parallel programming approach, Taft and COSMOS developer Andrew Pohorille, acting director of the NASA Astrobiology Institute, have been rebuilding the code to run 30,000-atom problems on RISC microprocessor-based systems. Historically, many important molecular dynamics problems of this size have not scaled well on "clustered" parallel systems. Lomax, with very fast shared memory, is ideal for such computations.

"The results of this work can benefit the molecular modeling industry in general because the newly developed numerical techniques are applicable to many popular industry standard models used by pharmaceutical research companies in the U.S.," says Taft.

The two-month optimization effort focused on inserting the Ames-developed shared memory Multilevel Protocol (MLP) parallelization technique into the code, The MLP technique allowed dramatic improvements on the code's two most time-consuming routines. The overall speedup arises from scaling efficiencies in the MLP-based parallel algorithm, coupled with greater reuse of encached data. Further optimizations For details about the COSMOS-MLP performance on the 512-processor SGI Origin, contact James Taft at jtaft@nas.nasa.gov.

5/2/00 -- 512-processor Origin Available to User Community
Lomax, the NAS Facility's 512-processor SGI Origin 2800 testbed system, became available on May 1 to about 200 NASA users. Adding Lomax to the mix of Origin systems at the supercomputing facility more than doubles the computing resources and memory available to those users.

Scientists in the High Performance Computing and Communications (HPCC) Program — specifically the Computational Aerosciences and Earth and Space Sciences projects — and NASA's Information Technology Program can now run bigger computing jobs in less time. The increase in nodes, faster processors (300 megahertz), and additional memory (768 megabytes per two-processor node) combine to make this system more advantageous for running large computational problems.

In addition, a new scheduling system was recently installed on Lomax. To make life easier for users, scheduling policies are similar to those on Hopper and Steger (the two original systems that comprised the Origin cluster), says Mary Hultquist, who led the SGI-NAS technical team responsible for getting the system ready on schedule. However, she cautions, because the system is still running as a testbed, system reliability is unpredictable and support is limited. Lomax support staff are available Monday - Friday, 6:00 a.m. to 5:00 p.m. Pacific time. However, regular User Services support is available 24 hours a day, seven days a week.

For more information on Lomax availability, contact NAS Engineering Branch Chief Bill Thigpen at bthigpen@mail.arc.nasa.gov.

4/25/00 -- IPG Team Reaches Milestone
NASA's Information Power Grid (IPG) team reached a significant milestone last week, demonstrating capabilities for remote connectivity and datamining. Using a locally written datamining application, the team accessed and retrieved catalogued archival data directly from IPG collaborators at Glenn Research Center in Ohio and at the San Diego Supercomputing Center. In addition, the program (aptly named "Miner") pulled data indirectly from computers at Caltech in Southern California and Washington University.

"The use of archival storage systems accessed transparently through a single, uniform interface running on systems at Ames clearly demonstrates part of the IPG vision to provide uniform access to widely distributed, heterogeneous Grid resources, "says IPG project manager William Johnston.

As part of the milestone, the team also demonstrated a sustained network transfer rate of 58 megabits per second. "While this is by no means high speed, the network connectivity lays the foundation for the next step — a high-speed interconnect test," says Leigh Ann Tanner, manager, advanced systems development. The team's next milestone is to deliver a "persistent testbed" for scientists to test their applications, and to provide the framework for systems software development. For more information about the IPG test results, contact Leigh Ann Tanner at tanner@nas.nasa.gov.

4/18/00 -- New NAS Tech Reports Available
Take a look at the newest NAS Technical Reports detailing the division's research activities. JavaGenes and Condor: Cycle scavenging Genetic Algorithms by Al Globus, explains a genetic algorithm code used to evolve pharmaceutical drug molecules and digital circuits. For more information, contact Globus at aglobus@arc.nasa.gov.

Field Encapsulation Library: the FEL 2.2 Reference Manual, by Patrick Moran and Chris Henze, documents features and functions for this library, which supports rapid development of computational fluid dynamics applications.

4/11/00 -- 3D Software Package Examines New Orbiter Designs
Cart3D, a software package developed by researchers at NASA Ames Research Center and New York University, is being used to examine potential orbiter redesigns, using the 512-processor Origin 2000 system at the NAS Facility. NAS researchers ran a test matrix of 180 simulations — 60 each for three separate orbiter redesigns — on Lomax, currently the largest single-image Origin 2000 system in existence. The test, conducted by Jeffrey Onufer and Donovan Mathias, examined 60 settings for control surfaces (including flaps, rudder, and speed-brake) and flight conditions (including Mach number, angle of attack, and angle of side-slip).

The Cart3D package allows end-to-end simulation of three-dimensional flows around complex vehicles, and can handle geometry from a variety of sources, included many major CAD packages. Cart3D automatically generates a three-dimensional, geometry-refined, Cartesian mesh for simulations. The software is currently used at over 80 government, industry, and university sites, and is available from the NASA Ames Commercial Technology Office. Cart3D development is funded by the Computational Aerosciences Project within NASA's High Performance Computing and Communications Program. For more information on Cart3D, contact Michael Aftosmis (aftosmis@nas.nasa.gov) in the NAS Research Branch. For test matrix results, contact Onufer (onufer@nas.nasa.gov) and Mathias (mathias@nas.nasa.gov).

4/4/00 -- Nanotechnology Research Presented at APS Meeting
Three NAS researchers presented their most recent findings in molecular nanotechnolgy at the March 2000 meeting of the American Physical Society (APS) in Minneapolis. Their research is important in designing nanotube-based materials used to make quantum leaps in computing speed and in creating ultra-strong and -lightweight materials for NASA launch vehicles.

Deepak Srivastava discussed studies on nanomechanics, hydrogen adsorption and diffusion,and the thermal conductivity of carbon and boron-nitride nanotubes. In one talk, "H Chemisorption and Diffusion on Single-wall Carbon Nanotubes," Srivastava and colleagues Fedor Dzegilenko (NASA Ames Research Center) and Madhu Menon (University of Kentucky, Lexington) presented findings that hydrogen atoms diffuse significantly faster on the inside of a single-wall carbon nanotube as compared to the outside surface.

Srivastava and Menon also presented "Anisotropic Plasticity of BN Nanotubes," which compared plastic deformation in compressed BN nanotubes and C nanotubes. In addition, Mohamed Osman (Washington State University) and Srivastava presented, "Temperature Dependence of Thermal Conductivity of Single-wall Carbon Nanotubes." For more information, send e-mail to deepak@nas.nasa.gov.

Other presentations by NAS researchers include:

"Transport Through Non-crossing Sub-bands of a Carbon Nanotube"
M.P Anantram (anant@nas.nasa.gov)

"Theory and Simulation of Electronic Structure of Deformed Carbon Nanotube"s
Liu Yang, Jie Han (han@nas.nasa.gov), M.P. Anantram, Richard Jaffe, Jianping Lu (University of North Carolina, Chapel Hill)