Computer simulation has become increasingly important in many scientific disciplines, but its performance and scalability are severely limited by the memory throughput on today’s computer systems. With the support of this grant, we first designed training-based prediction, which accurately predicts the memory performance of large applications before their execution. Then we developed optimization techniques using dynamic computation fusion and large-scale data transformation. The research work has three major components. The first is modeling and prediction of cache behav- ior. We have developed a new technique, which uses reuse distance information from training inputs then extracts a parameterized model of the program’s cache miss rates for any input size and for any size of fully associative cache. Using the model we have built a web-based tool using three dimensional visualization. The new model can help to build cost-effective computer systems, design better benchmark suites, and improve task scheduling on heterogeneous systems. The second component is global computation for improving cache performance. We have developed an algorithm for dynamic data partitioning using sampling theory and probability distribution. Recent work from a number of groups show that manual or semi-manual computation fusion has significant benefits in physical, mechanical, and biological simulations as well …

Advanced Research Projects Agency-Energy project sheet summarizing general information about the 15 projects that are a part of the Building Energy Efficiency Through Innovative Thermodevices (BEETIT) program including project goals, innovation needs, and potential impacts.

Proton radiography has become an important tool for predicting the performance of stockpiled nuclear weapons. Current proton radiography experiments at LANSCE are confined to relatively small targets on the order of centimeters in size because of the low beam energy. LANL scientists have made radiographs with 12 and 24 GeV protons produced by the accelerator at Brookhaven National Laboratory. These energies are in the range required for hydrotest radiography. The design of a facility for hydrotest radiography requires knowledge of the cross sections for producing high-energy particles in the forward direction, which are incorporated into the Monte Carlo simulation used in designing the beam and detectors. There are few existing measurements of neutron production cross sections for proton-nuclei interactions in the 50 GeV range, and almost no data exist for forward neutron production, especially for heavy target nuclei. Thus the data from the MIPP EMCAL and HCAL, for which our group was responsible, are critical to proton radiography. Since neutrons and photons cannot be focused by magnets, they cause a background “fog” on the images. This problem can be minimized by careful design of the focusing system and detectors. The purpose of our research was to measure forward production of …

Advanced Research Projects Agency-Energy project sheet summarizing general information about the Building Energy Efficiency Through Innovative Thermodevices (BEETIT) program including critical needs, innovation and advantages, impacts, and contact information. This sheet discusses air conditioning that would be more efficient and not use polluting refrigerants as part of the "Non-Equilibrium Asymmetic Thermoelectrics (NEAT) Devices" project.

The Chariot site is located in the Ogotoruk Valley in the Cape Thompson region of northwest Alaska. This region is about 125 miles north of (inside) the Arctic Circle and is bounded on the southwest by the Chukchi Sea. The closest populated areas are the Inupiat villages of Point Hope, 32 miles northwest of the site, and Kivalina,41 miles to the southeast. The site is accessible from Point Hope by ATV in the summer and by snowmobile in the winter. Project Chariot was part of the Plowshare Program, created in 1957 by the U.S. Atomic Energy Commission (AEC), a predecessor agency of the U.S. Department of Energy (DOE), to study peaceful uses for atomic energy. Project Chariot began in 1958 when a scientific field team chose Cape Thompson as a potential site to excavate a harbor using a series of nuclear explosions. AEC, with assistance from other agencies, conducted more than40 pretest bioenvironmental studies of the Cape Thompson area between 1959 and 1962; however, the Plowshare Program work at the Project Chariot site was cancelled because of strong public opposition. No nuclear explosions were conducted at the site.

Dense plasma diagnostics, soft x-ray laser interferometry, converging plasmas.

The voltage or electric potential difference across the terminals of a cell when no current is drawn from it. The emf of a cell is the sum of the electric potential differences (PDs) produced by a separation of charges (electrons or ions) that can occur at each phase boundary (or interface) in the cell. The magnitude of each PD depends on the chemical nature of the two contacting phases. Thus, at the interface between two different metals, some electrons will have moved from the metal with a higher free energy of electrons to the metal with a lower free energy of electrons. The resultant charge separation will produce a PD (just as charge separation produces a voltage across a capacitor) that, at equilibrium, exactly opposes further electron flow. Similarly, PDs can be produced when electrons partition across a metal/solution interface or metal/solid interface, and when ions partition across a solution/membrane/solution interface.