An overview of several aspects of the weathering of roofing materials is presented. Degradation of materials initiated by ultraviolet radiation is discussed for plastics used in roofing, as well as wood and asphalt. Elevated temperatures accelerate many deleterious chemical reactions and hasten diffusion of material components. Effects of moisture include decay of wood, acceleration of corrosion of metals, staining of clay, and freeze-thaw damage. Soiling of roofing materials causes objectionable stains and reduces the solar reflectance of reflective materials. (Soiling of non-reflective materials can also increase solar reflectance.) Soiling can be attributed to biological growth (e.g., cyanobacteria, fungi, algae), deposits of organic and mineral particles, and to the accumulation of flyash, hydrocarbons and soot from combustion.

This RD&D project is a multi-institutional effort to develop a hybrid solar lighting (HSL) system that transports daylight from a paraboloidal dish concentrator to a luminaire via a bundle of polymer fiber optics. The luminaire can be a device to distribute sunlight into a space for the production of algae for CO{sub 2} sequestration or it can be a device that is a combination of daylighting and electric lighting for space/task lighting. In this project, the sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. For the third generation (beta) system, the secondary mirror is an ellipsoidal mirror that directs the visible light into a bundle of 3 mm diameter fibers. The IR spectrum is filtered out to minimize unnecessary heating at the fiber entrance region. This report describes the major achievements from this research that began in August 2001.

Pratt & Whitney Rocketdyne (PWR) has developed an innovative gasifier concept that uses rocket engine technology to significantly improve gasifier performance, life, and cost compared to current state-of-the-art systems. One key feature of the PWR concept is the use of an ultra-dense phase feed system to provide dry coal to the multi-element injector. This report describes the design of an ultra-dense phase multi-element injector and feed system for use on PWR gasifiers operating at pressures to 1,000 psia. For the design of this injector and feed system, the pulverized coal's Bingham fluid yield stress is approximately 11 Pascals (Pa) with a coefficient of rigidity of 10 centipoise (cp). These values are typical of earlier experimental testing conducted with dried pulverized coal below 18 wt% moisture -- see, e.g., Sprouse and Schuman (1983, 1986). Each individual injector element is designed for a coal flow rate between 3 and 4 tons/hr (0.76 to 1.0 kg/sec) at full flow conditions. Hence, a small 400 to 500 tons/day (4.2 to 5.25 kg/sec) gasifier will require a 6-element injector, a 1,500 tons/day (15.7 kg/sec) gasifier will require an 18-element injector and a 3,000 tons/day (31.5 kg/sec) gasifier will require a 36-element injector. These injectors and …

Bitmap indices have been widely used in scientific applications and commercial systems for processing complex,multi-dimensional queries where traditional tree-based indices would not work efficiently. A common approach for reducing the size of a bitmap index for high cardinality attributes is to group ranges of values of an attribute into bins and then build a bitmap for each bin rather than a bitmap for each value of the attribute. Binning reduces storage costs,however, results of queries based on bins often require additional filtering for discarding it false positives, i.e., records in the result that do not satisfy the query constraints. This additional filtering,also known as ''candidate checking,'' requires access to the base data on disk and involves significant I/O costs. This paper studies strategies for minimizing the I/O costs for ''candidate checking'' for multi-dimensional queries. This is done by determining the number of bins allocated for each dimension and then placing bin boundaries in optimal locations. Our algorithms use knowledge of data distribution and query workload. We derive several analytical results concerning optimal bin allocation for a probabilistic query model. Our experimental evaluation with real life data shows an average I/O cost improvement of at least a factor of 10 for …

Flue gas desulphurization (FGD) materials are produced in abundant quantities by coal burning utilities. Due to environmental restrains, flue gases must be ''cleaned'' prior to release to the atmosphere. They are two general methods to ''scrub'' flue gas: wet and dry. The choice of scrubbing material is often defined by the type of coal being burned, i.e. its composition. Scrubbing is traditionally carried out using a slurry of calcium containing material (slaked lime or calcium carbonate) that is made to contact exiting flue gas as either a spay injected into the gas or in a bubble tower. The calcium combined with the SO{sub 2} in the gas to form insoluble precipitates. Some plants have been using dry injection of these same materials or their own Class C fly ash to scrub. In either case the end product contains primarily hannebachite (CaSO{sub 3} {center_dot} 1/2H{sub 2}O) with smaller amounts of gypsum (CaSO{sub 4} {center_dot} 2H{sub 2}O). These materials have little commercial use. Experiments were carried out that were meant to explore the feasibility of using blends of hannebachite and fly ash mixed with concentrated sodium hydroxide to make masonry products. The results suggest that some of these mixtures could be used …

RMI support in Babel has two main goals: transparency & flexibility. Transparency meaning that the new RMI features are entirely transparent to existing Babelized code; flexibility meaning the RMI capability should also be flexible enough to support a variety of RMI transport implementations. Babel RMI is a big success in both areas. Babel RMI is completely transparent to already Babelized implementation code, allowing painless upgrade, and only very minor setup changes are required in client code to take advantage of RMI. The Babel RMI transport mechanism is also extremely flexible. Any protocol that implements Babel's minimal, but complete, interface may be used as a Babel RMI protocol. The Babel RMI API allows users to select the best protocol and connection model for their application, whether that means a WebServices-like client-server model for use over a WAP, or a faster binary peer-to-peer protocol for use on different nodes in a leadership-class supercomputer. Users can even change protocols without recompiling their code. The goal of this paper is to give network researchers and protocol implementors the information they need to develop new protocols for Babel RMI. This paper will cover both the high-level interfaces in the Babel RMI API, and the low …

One goal of the Building Energy Codes Program (BECP) is to provide useful, easy to understand information about the national energy codes. A forum where users could ask for, and receive clarification on these codes and software from other users would allow the Energy codes project to reach and instruct a broader audience for a modest resource cost. The forum proposed would be a staff moderated discussion board where staff would post topics, and users would post discussion of those topics, with staff joining in to the discussions. The forum would be moderated by staff members, to remove objectionable and irrelevant postings, and to answer any technical questions that arise. The topics and discussions would be archived and searchable to allow users to answer their own questions, if they pertain to a previously discussed topic.

Control of workplace exposure to beryllium is a growing issue in the United States and other nations. As the health risks associated with low-level exposure to beryllium are better understood, the need increases for improved analytical techniques both in the laboratory and in the field. These techniques also require a greater degree of standardization to permit reliable comparison of data obtained from different locations and at different times. Analysis of low-level beryllium samples, in the form of air filters or surface wipes, is frequently required for workplace monitoring or to provide data to support decision-making on implementation of exposure controls. In the United States and the United Kingdom, the current permissible exposure level is 2 {micro}g/m{sup 3} (air), and the United States Department of Energy has implemented an action level of 0.2 {micro}g/m{sup 3} (air) and 0.2 {micro}g/100 cm{sup 2} (surface). These low-level samples present a number of analytical challenges, including (1) a lack of suitable standard reference materials, (2) unknown robustness of sample preparation techniques, (3) interferences during analysis, (4) sensitivity (sufficiently low detection limits), (5) specificity (beryllium speciation), and (6) data comparability among laboratories. Additionally, there is a need for portable, real-time (or near real-time) equipment for beryllium …

Recently the results from many Monte Carlo codes were compared for a series of theoretical pin-cells; the results are documented in ref. [3]; details are also provided here in Appendix A and B. The purpose of this earlier code comparison was primarily to determine how accurately our codes model both bound and free atom neutron thermal scattering. Prior to this study many people assumed that our Monte Carlo transport codes were all now so accurate that they would all produce more or less the same answers, say for example K-eff to within 0.1%. The results demonstrated that in reality we see a rather large spread in the results for even simple scalar parameters, such as K-eff, where we found differences in excess of 2%, far exceeding many people's expectations. The differences between code results were traced to four major factors, (1) Differences between the sets of nuclear data used. (2) The accuracy of nuclear data processing codes. (3) The accuracy of the models used in our Monte Carlo transport codes. (4) Code user selected input options. Naturally at Livermore we would like to insure that we minimize the effects of these factors. In this report we compare the results using …

Time-to-digital converters with sub-picosecond resolutions are needed to satisfy the requirements of time-on-flight measurements of the next generation of high energy and nuclear physics experiments. The converters must be highly integrated, power effective, low cost, and feature plug-and-play capabilities to handle the increasing number of channels (up to hundreds of millions) in future Department of Energy experiments. Current state-off-the-art time-to-digital converter integrated circuits do not have the sufficient degree of integration and flexibility to fulfill all the described requirements. During Phase I, the Advanced Science and Novel Technology Company in cooperation with the nuclear physics division of the Oak Ridge National Laboratory has developed the architecture of a novel time-to-digital converter with multiple channels connected to an external processor through a special interfacing block and synchronized by clock signals generated by an internal phase-locked loop. The critical blocks of the system including signal delay lines and delay-locked loops with proprietary differential delay cells, as well as the required digital code converter and the clock period counter have been designed and simulated using the advanced SiGe120 BiCMOS technological process. The results of investigations demonstrate a possibility to achieve the digitization accuracy within 1ps. ADSANTEC has demonstrated the feasibility of the proposed …

The photo-induced enhancement of second harmonic generation, and the effect of nanocrystal shape and pump intensity on confined acoustic phonons in semiconductor nanocrystals, has been investigated with time-resolved scattering and absorption measurements. The second harmonic signal showed a sublinear increase of the second order susceptibility with respect to the pump pulse energy, indicating a reduction of the effective one-electron second-order nonlinearity with increasing electron-hole density in the nanocrystals. The coherent acoustic phonons in spherical and rod-shaped semiconductor nanocrystals were detected in a time-resolved absorption measurement. Both nanocrystal morphologies exhibited oscillatory modulation of the absorption cross section, the frequency of which corresponded to their coherent radial breathing modes. The amplitude of the oscillation also increased with the level of photoexcitation, suggesting an increase in the amplitude of the lattice displacement as well.

We have compared the results produced by a variety of currently available Monte Carlo neutron transport codes for the relatively simple problem of a fast source of neutrons slowing down and thermalizing in water. Initial comparisons showed rather large differences in the calculated flux; up to 80% differences. By working together we iterated to improve the results by: (1) insuring that all codes were using the same data, (2) improving the models used by the codes, and (3) correcting errors in the codes; no code is perfect. Even after a number of iterations we still found differences, demonstrating that our Monte Carlo and supporting codes are far from perfect; in particularly we found that the often overlooked nuclear data processing codes can be the weakest link in our systems of codes. The results presented here represent the today's state-of-the-art, in the sense that all of the Monte Carlo codes are modern, widely available and used codes. They all use the most up-to-date nuclear data, and the results are very recent, weeks or at most a few months old; these are the results that current users of these codes should expect to obtain from them. As such, the accuracy and limitations …

Professors and graduate students from five universities--the University of Kentucky, University of Pittsburgh, University of Utah, West Virginia University, and Auburn University--are collaborating in a research program to develop C1 chemistry processes to produce ultra-clean liquid transportation fuels and hydrogen, the zero-emissions transportation fuel of the future. The feedstocks contain one carbon atom per molecular unit. They include synthesis gas (syngas), a mixture of carbon monoxide and hydrogen produced by coal gasification or reforming of natural gas, methane, methanol, carbon dioxide, and carbon monoxide. An important objective is to develop C1 technology for the production of liquid transportation fuel and hydrogen from domestically plentiful resources such as coal, coalbed methane, and hydrocarbon gases and liquids produced from coal. An Advisory Board with representatives from Chevron-Texaco, Eastman Chemical, Conoco-Phillips, the Air Force Research Laboratory, the U.S. Army National Automotive Center, and Tier Associates provides guidance on the practicality of the research. The current report summarizes the results obtained in this program during the period October 1, 2002 through March 31, 2006. The results are presented in detailed reports on 16 research projects headed by professors at each of the five CFFS Universities and an Executive Summary. Some of the highlights from …

Large scale scientific data is often stored in scientific data formats such as FITS, netCDF and HDF. These storage formats are of particular interest to the scientific user community since they provide multi-dimensional storage and retrieval. However, one of the drawbacks of these storage formats is that they do not support semantic indexing which is important for interactive data analysis where scientists look for features of interests such as ''Find all supernova explosions where energy > 10{sup 5} and temperature > 10{sup 6}''. In this paper we present a novel approach called HDF5-FastQuery to accelerate the data access of large HDF5 files by introducing multi-dimensional semantic indexing. Our implementation leverages an efficient indexing technology called bitmap indexing that has been widely used in the database community. Bitmap indices are especially well suited for interactive exploration of large-scale read only data. Storing the bitmap indices into the HDF5 file has the following advantages: (a) Significant performance speedup of accessing subsets of multi-dimensional data and (b) portability of the indices across multiple computer platforms. We will present an API that simplifies the execution of queries on HDF5 files for general scientific applications and data analysis. The design is flexible enough to accommodate …

This report presents a summary of research projects in the area of low energy nuclear reactions and structure, carried out between 1 January 2003 and 31 December 2005 and supported by U.S. DOE grant number DE-FG03-03NA00074. Cross sections measured with high resolution have been subjected to an Ericson theory analysis to infer information about the nuclear level density. Other measurements were made of the spectral shape of particles produced in evaporation processes; these also yield level density information. A major project was the development of a new Hauser-Feshbach code for analyzing such spectra. Other measurements produced information on the spectra of gamma rays emitted in reactions on heavy nuclei and gave a means of refining our understanding of gamma-ray strength functions. Finally,reactions on light nuclei were studied and subjected to an R-matrix analysis. Cross sections fora network of nuclear reactions proceedingthrough a given compound nucleus shouldgreatly constrain the family of allowed parameters. Modifications to the formalism andcomputer code are also discussed.

The U.S. Department of Energy Order 435.1, Radioactive Waste Management, requires a disposal authorization statement authorizing operation (or continued operation) for low-level waste disposal facilities. In fulfillment of these requirements, a disposal authorization statement was issued on October 25, 1999, authorizing the Hanford Site to transfer, receive, possess, and dispose of low-level radioactive waste at the 200 East Area burial grounds and the 200 West Area burial grounds. One of the conditions is that monitoring plans for the 200 East Area and 200 West Area low-level burial grounds be written and approved by the Richland Operations Office. As a result of a record of decision for the Hanford Site Solid Waste Program and acceptance of the Hanford Site Solid Waste Environmental Impact Statement, the use of the low-level burial ground (LLBG) as a disposal facility for low-level and mixed low-level wastes has been restricted to lined trenches and the Navy reactor-compartment trench only. Hence, as of July 2004, only the two lined trenches in burial ground 218-W-5 (trenches 31 and 34, see Appendix A) and the Navy reactor-compartment trench in burial ground 218 E 12B (trench 94) are allowed to receive waste. When the two lined trenches are filled, the …

The task of searching for patterns in graph-structured data has applications in such diverse areas as computer vision, biology, electronics, computer aided design, social networks, and intelligence analysis. As such, work on graph-based pattern matching spans a wide range of research communities. Due to variations in graph characteristics and problem requirements, graph-based pattern matching is not a single problem, but a set of related problems. This paper presents a survey of existing work on graph-based pattern matching, describing variations among graph matching problems, general and specific solution approaches, evaluation techniques, and directions for further research. An emphasis is given to techniques that apply to general graphs with semantic characteristics. The survey also discusses techniques for graph mining, an extension of the graph matching problem.

We demonstrate the recently developed technique of laser driven isentropic compression (ICE) for dynamically compressing Al samples at high loading rates close to the room temperature isentrope and up to peak stresses above 100GPa. Upon analysis of the unloading profiles from a multi-stepped Al/LiF target a continuous path through Stress-Density space may be calculated. For materials with phase transformations ramp compression techniques reveals the location of equilibrium phase boundaries and provide information on the kinetics of the lattice re-ordering.