Version 3 of the Hadley Centre Atmospheric Model (HadAM3) has been used to demonstrate one means of comparing a general circulation model with observations for a specific climate perturbation, namely the strong 1997/98 El Nino. This event was characterized by the collapse of the tropical Pacific's Walker circulation, caused by the lack of a zonal sea surface temperature gradient during the El Nino. Relative to normal years, cloud altitudes were lower in the western portion of the Pacific and higher in the eastern portion. HadAM3 likewise produced the observed collapse of the Walker circulation, and it did a reasonable job of reproducing the west/east cloud structure changes. This illustrates that the 1997/98 El Nino serves as a useful means of testing cloud-climate interactions in climate models.

Optimizing compilers have a long history of applying loop transformations to C and Fortran scientific applications. However, such optimizations are rare in compilers for object-oriented languages such as C++ or Java, where loops operating on user-defined types are left unoptimized due to their unknown semantics. Our goal is to reduce the performance penalty of using high-level object-oriented abstractions. We propose an approach that allows the explicit communication between programmers and compilers. We have extended the traditional Fortran loop optimizations with an open interface. Through this interface, we have developed techniques to automatically recognize and optimize user-defined array abstractions. In addition, we have developed an adapted constant-propagation algorithm to automatically propagate properties of abstractions. We have implemented these techniques in a C++ source-to-source translator and have applied them to optimize several kernels written using an array-class library. Our experimental results show that using our approach, applications using high-level abstractions can achieve comparable, and in cases superior, performance to that achieved by efficient low-level hand-written codes.

I recently spent a summer as an intern at the Lawrence Livermore National Laboratory. I worked on a project involving the real-time, reagentless, single cell detection of aerosolized pathogens using a novel mass spectrometry approach called Bio-Aerosol Mass Spectrometry (BAMS). Based upon preliminary results showing the differentiation capabilities of BAMS, I would like to explore the development and use of this novel detection system in the context of both environmental and clinical sample pathogen detection. I would also like to explore the broader public health applications that a system such as BAMS might have in terms of infectious disease prevention and control. In order to appreciate the potential of this instrument, I will demonstrate the need for better pathogen detection methods, and outline the instrumentation, data analysis and preliminary results that lead me toward a desire to explore this technology further. I will also discuss potential experiments for the future along with possible problems that may be encountered along the way.

The high-level radioactive wastes in many single-shell tanks (SSTs) at the Hanford Site are to be retrieved by a modified sluicing method that uses water jets to dissolve the water-soluble waste and mobilize the water-insoluble waste. Retrieval operations will liberate any waste gases trapped in the wetted solid waste matrix, and these gases will be released into the tank headspaces. Because the trapped gases include the flammable species hydrogen, methane, and ammonia, a concern exists that a flammable mixture could be formed in the tank headspaces. This report combines conservative retained gas inventory estimates and tank data with anticipated waste retrieval rates to estimate the potential headspace flammability of selected SSTs during modified sluicing waste retrieval operations. Considered here are nine of the 12 tanks from the 241-S tank farm (241-S-107, 241-S-111, and 241-S 112 are not considered) and Tank 241-U-107. This report is intended to support the specification of process controls that ensure flammable conditions do not develop in the tank headspaces. Consequently, the physical scenarios considered, the models developed to estimate retained gas releases and the tank headspace compositions under these scenarios, and the model input data are intended to conservatively assess the potential to reach headspace flammability. …

This report summarizes the science and technology research and development efforts in Lawrence Livermore National Laboratory's Engineering Directorate for FY2003, and exemplifies Engineering's 50-year history of researching and developing the engineering technologies needed to support the Laboratory's missions. Engineering has been a partner in every major program and project at the Laboratory throughout its existence, and has prepared for this role with a skilled workforce and the technical resources developed through venues like the Laboratory Directed Research and Development Program (LDRD). This accomplishment is well summarized by Engineering's mission: ''Enable program success today and ensure the Laboratory's vitality tomorrow.'' Engineering's investment in technologies is carried out through two programs, the LDRD program and the ''Tech Base'' program. LDRD is the vehicle for creating those technologies and competencies that are cutting edge, or that require a significant level of research, or contain some unknown that needs to be fully understood. Tech Base is used to apply those technologies, or adapt them to a Laboratory need. The term commonly used for Tech Base projects is ''reduction to practice.'' Therefore, the LDRD report covered here has a strong research emphasis. Areas that are presented all fall into those needed to accomplish our mission. …

There is considerable impetus for identification of aqueous OM catalysts as water is the ultimate ''green'' solvent. In collaboration with researchers at Ames Lab, we investigated effective fragment and Monte Carlo techniques for aqueous-phase hydroformylation (HyF). The Rh of the HyF catalyst is weakly aquated, in contrast to the hydride of the Rh-H bond. As the insertion of the olefin C=C into Rh-H determines the linear-to-branched aldehyde ratio, it is reasonable to infer that solvent plays an important role in regiochemistry. Studies on aqueous-phase organometallic catalysis were complemented in studies of the gas-phase reaction. A Rh-carbonyl-phosphine catalyst was investigated. Two of the most important implications of this research include (a) pseudorotation among five-coordinate intermediates is significant in HyF, and (b) CO insertion is the rate-determining step. The latter is in contrast to experimental deductions, highlighting the need for more accurate modeling. To this end, we undertook studies of (a) experimentally relevant PR{sub 3} co-ligands (PMe{sub 3}, PPh{sub 3}, P(p-PhSO{sub 3{sup -}}){sub 3}, etc.), and (b) HyF of propene. For the propylene research, simulations indicated that the linear: branched aldehyde ratio (linear is more desirable) is determined by thermodynamic discrimination of two distinct pathways. Other projects include a theory-experiment study of …

The overall objective of this project is to increase heavy oil reserves in slope and basin clastic (SBC) reservoirs through the application of advanced reservoir characterization and thermal production technologies. The project involves improving thermal recovery techniques in the Tar Zone of Fault Blocks II-A and V (Tar II-A and Tar V) of the Wilmington Field in Los Angeles County, near Long Beach, California. A primary objective is to transfer technology which can be applied in other heavy oil formations of the Wilmington Field and other SBC reservoirs, including those under waterflood. The thermal recovery operations in the Tar II-A and Tar V have been relatively inefficient because of several producibility problems which are common in SBC reservoirs. Inadequate characterization of the heterogeneous turbidite sands, high permeability thief zones, low gravity oil, and nonuniform distribution of remaining oil have all contributed to poor sweep efficiency, high steam-oil ratios, and early steam breakthrough. Operational problems related to steam breakthrough, high reservoir pressure, and unconsolidated formation sands have caused premature well and downhole equipment failures. In aggregate, these reservoir and operational constraints have resulted in increased operating costs and decreased recoverable reserves. The advanced technologies to be applied include: (1) Develop three-dimensional …

It is well established that bitmap indices are efficient for read-only attributes with a small number of distinct values. For an attribute with a large number of distinct values, the size of the bitmap index can be very large. To over come this size problem, specialized compression schemes are used. Even though there is empirical evidence that some of these compression schemes work well, there has not been any systematic analysis of their effectiveness. In this paper, we analyze the time and space complexities of the two most efficient bitmap compression techniques known, the Byte-aligned Bitmap Code (BBC) and the Word-Aligned Hybrid (WAH) code, and study their performance on high cardinality attributes. Our analyses indicate that both compression schemes are optimal in time. The time and space required to operate on two compressed bitmaps are proportional to the total size of the two bitmaps. We demonstrate further that an in-place OR algorithm can operate on a large number of sparse bitmaps in time linear in their total size. Our analyses also show that the compressed indices are relatively small compared with commonly used indices such as B-trees. Given these facts, we conclude that bitmap index is efficient on attributes of …

A Family of Durable Silver Mirror Designs has been fabricated at LLNL. We report here on the optical and environmental performance of the basic design, which can be cleaned with standard glass cleaner and cloth after months of exposure to outside atmosphere.

The principal research effort for Year 1 of the project is T-R cycle characterization and modeling. The research focus for the first nine (9) months of Year 1 is on outcrop study, well log analysis, seismic interpretation and data integration and for the remainder of the year the emphasis is on T-R cycle model development.

We have obtained very promising results in the Phase I study. Specifically, for temperature effects, we have established that piezoelectric cantilever sensors could retain their resonance peak strength at high temperatures, i.e., the Q values of the resonance peaks remained above 10 even when the temperature was very close to the Curie temperature. This confirms that a piezoelectric cantilever sensor can be used as a sensor up to its Curie temperature. Furthermore, we have shown that the mass detection sensitivity remained unchanged at different temperatures. For selective gas detection, we have demonstrated selective NH{sub 3} detection using piezoelectric cantilever sensors coated with mesoporous SiO{sub 2}. For high-temperature sensor materials development, we have achieved highly oriented Sr-doped lead titanate thin films that possessed superior dielectric and ferroelectric properties. Such highly oriented films can be microfabricated into high-performance piezoelectric microcantilever sensors that can be used up to 490 C. We have accomplished the goal of Phase I study in exploring the various aspects of a high-temperature gas sensor. We propose to continue the study in Phase II to develop a sensor that is suitable for high-temperature applications using piezoelectrics with a high Curie temperature and by controlling the effects of temperature. The …