Experiments were performed to understand the complex fluid-structure interactions that occur during aircraft internal store carriage. A cylindrical store was installed in a rectangular cavity having a length-to-depth ratio of 3.33 and a length-to-width ratio of 1. The Mach number ranged from 0.6 to 2.5 and the incoming boundary layer was turbulent. Fast-response pressure measurements provided aeroacoustic loading in the cavity, while triaxial accelerometers provided simultaneous store response. Despite occupying only 6% of the cavity volume, the store significantly altered the cavity acoustics. The store responded to the cavity flow at its natural structural frequencies, and it exhibited a directionally dependent response to cavity resonance. Specifically, cavity tones excited the store in the streamwise and wall-normal directions consistently, whereas a spanwise response was observed only occasionally. The streamwise and wall-normal responses were attributed to the longitudinal pressure waves and shear layer vortices known to occur during cavity resonance. Although the spanwise response to cavity tones was limited, broadband pressure fluctuations resulted in significant spanwise accelerations at store natural frequencies. The largest vibrations occurred when a cavity tone matched a structural natural frequency, although energy was transferred more efficiently to natural frequencies having predominantly streamwise and wall-normal motions.
Long-term corrosion experiments have been performed on Alloy 22 (UNS N06022), in a series of heated brines formulated to represent evaporatively concentrated ground water, to evaluate the long-term corrosion performance of the material. These solutions included 0.5 M NaCl, in addition to two simulated concentrated ground water solutions. Under conditions where Alloy 22 was anticipated to be passive, the corrosion rate was found to be vanishingly small (i.e., below the resolution of the weight-loss technique used to quantify corrosion in this study). However, under low pH conditions where Alloy 22 was anticipated to be active, or more specifically, where the chromium oxide passive film was not thermodynamically stable, the corrosion rate was appreciable. Furthermore, under such conditions the corrosion rate was observed to be a strong function of temperature, with an activation energy of 72.9±1.8 kJ/mol. Time of Flight-Secondary Ion Mass Spectroscopy analysis of the oxide layer revealed that, while sulfur was present within the oxide for all test conditions, no accumulation was observed at or near the metal/oxide interface. These observations confirm that inhibition of passive film formation via sulfur accumulation does not occur during the corrosion of Alloy 22.
Performance and energy are critical aspects in high performance computing (HPC) data centers. Highly parallel HPC applications that require multiple nodes usually run for long durations in the range of minutes, hours or days. As the threads of parallel applications communicate with each other intensively, the communication cost of these applications has a significant impact on data center performance. Energy consumption has also become a first-order constraint of HPC data centers. Nearly half of the energy in the computing clusters today is consumed by the cooling infrastructure. Existing job allocation policies either target improving the system performance or reducing the cooling energy cost of the server nodes. How to optimize the system performance while minimizing the cooling energy consumption is still an open question. This paper proposes a job allocation methodology aimed at jointly reducing the communication cost and the cooling energy of HPC data centers. In order to evaluate and validate our optimization algorithm, we implement our joint job allocation methodology in the structural simulation toolkit (SST) - a simulation framework for large-scale data centers. We evaluate our joint optimization algorithm using traces extracted from real-world workloads. Experimental results show that, in comparison to performance-aware job allocation algorithms, our algorithm achieves comparable running times and reduces the cooling power by up to 42.21% across all the jobs.
Sandia National Laboratories (SNL) has been tasked with the design of a modern transportable container (MTC) for use in high reliability transportation environments. The container is required to transport cargo capable of generating its own heat and operate under the United States’ climatic extremes. In response to these requirements, active heating and cooling is necessary to maintain a controlled environment inside the container. The following thesis project documents the design of an active heating, active cooling, and combined active heating and cooling system (now referred to as active heating and cooling systems) through computational thermal analyses, scoping of commercial system options, and mechanical integration with the container’s structure.
The anticipated magnitude of needed investments in new transmission infrastructure in the U.S. requires that these be allocated in a way that maximizes the likelihood of achieving society's goals for power system operation. The use of state-of-the-art optimization tools can identify cost-effective investment alternatives, extract more benefits out of transmission expansion portfolios, and account for the huge economic, technology, and policy uncertainties that the power sector faces over the next several decades.
We present calculations for the field of view (FOV), image fluence, image monochromaticity, spectral acceptance, and image aberrations for spherical crystal microscopes, which are used as self-emission imaging or backlighter systems at large-scale high energy density physics facilities. Our analytic results are benchmarked with ray-tracing calculations as well as with experimental measurements from the 6.151 keV backlighter system at Sandia National Laboratories. The analytic expressions can be used for x-ray source positions anywhere between the Rowland circle and object plane. This enables quick optimization of the performance of proposed but untested, bent-crystal microscope systems to find the best compromise between FOV, image fluence, and spatial resolution for a particular application.
Sandia National Laboratories is evaluating alternative gravity bomb flight test (GBFT) options that might be more cost effective in the 2025 timeframe than the current Tonopah Test Range (TTR) facility. The alternate ranges being considered are White Sands Missile Range (WSMR) and the Nevada National Security Site (NNSS). One of the factors considered in the decision process is if the geology of the alternative sites is suitable for gravity bomb flight testing. The study looked at seven specific sites within the three test ranges, including the TTR. Those seven sites are Main Lake and Antelope Lake at TTR, Trinity Lake at WSMR, and Yucca Lake, an area west of Frenchman Flat, Pahute Mesa, and the Pahute Airstrip all at NNSS. The four lakes studied are playas. In general the findings indicate that the playa lakes (Main, Antelope, Trinity, and Yucca) consist of fine-grained lacustrine sediments with inter-bedded stringers of coarse grains and gravels towards the shorelines. Frenchman Flat and Pahute Airstrip are both located within basins filled with poorly sorted gravel alluviums. Pahute Mesa consists of volcanic tuff. The seven sites are listed in order from the most favorable location to least favorable based on the suitability of the geology for GBFT. An ideal test site would consist of a succession of soft sediments devoid of hard layers. WSMR Lake Trinity is the most suitable site, exhibiting solely find-grained sediments across the study region. The lakes at TTR follow next with Antelope Lake and Main Lake, Antelope lake being finer grained and more homogeneous than Main Lake. The four NNSS sites are considered the least favorable due the heterogenetic character of Yucca Lake, Pahute Airstrip, and Frenchman Flat. The geology of Pahute Mesa is considered the least favorable consisting of volcanic tuff too hard for current test operations.
This project focused on developing a novel, scalable, and economic growth technique for bulk gallium nitride (GaN), a critical material for next-generation high-temperature power electronics. Large area, high-quality bulk GaN is required as a substrate material in order to grow highly efficient bipolar transistors for inverters and power conditioning. Attempting to grow GaN in bulk by traditional precipitation methods forces extreme thermodynamic and kinetic conditions, putting these techniques at the extremes of experimental science, which is unsuitable for large-area, cost-effective substrate growth. The Electrochemical Solution Growth (ESG) technique is a novel concept that addresses these issues in a unique way, and was developed at Sandia National Laboratories (SNL), in part under this program. The crucial step in demonstrating the technique’s feasibility was to deposit high-quality GaN on a seed crystal. The bulk of SNL’s activities were focused on developing conditions for deposition of GaN on a seed crystal (a thin film of GaN grown by metal organic chemical vapor phase deposition (MOCVD) on c-axis oriented sapphire) in a molten salt electrolyte solution using a rotating disk reactor (RDR) ESG apparatus. This project was actively funded from FY08 to FY12 by the Energy Storage Program and GaN Initiative for Grid Applications (GIGA) program of the Office of Electricity Delivery and Energy Reliability (OE) in the U.S. Department of Energy (DOE). Some activities focused on silicon doping of GaN occurred in FY13 but only through the use of carryover funds.
The American Recovery and Reinvestment Act (ARRA) of 2009 (Recovery Act) provided funding for 16 energy storage demonstration projects. The projects ranged in scope from feasibility studies and technology demonstrations to full-scale, operational energy storage plants. This investment had a significant positive impact on the grid-connected energy storage industry. The goal of this report is to summarize the lessons learned from the ARRA projects, and to make recommendations for future Department of Energy (DOE) investments. Information for this report primarily came from three sources: a questionnaire and interview with each project team; DOE energy storage program peer review presentations; and DOE reports required as part of the ARRA project. Some lessons learned were common to many projects. Development of standards, codes and protocols specific to energy storage systems will mitigate uncertainty over code compliance, streamline permitting, and should be a priority (especially related to safety). Removal of regulatory barriers that preclude optimal operation of an energy storage system with multiple applications would immediately enable further deployment (e.g., FERC standards preclude the marketing department from reliability activities). Maturity of the approach to monetization varies substantially between applications with frequency regulation as an ancillary service leading other applications. Finally, developers focused on ramp mitigation and time shifting envision a reference plant. This reference plant would scale up from the current demonstration systems and would lead to the deployment of 50 MW-scale peaker plants.
The current management system in the United States for commercial spent nuclear fuel does not emphasize integration among storage, transportation, and disposal. Unless a path can be implemented that addresses the long-term needs for integration, the United States could end up leaving substantial quantities of stranded commercial spent nuclear fuel stored at decommissioned reactor sites in an increasingly wide variety of containers. This lack of integration does not cause safety issues, but may delay transporting the spent fuel and complicate options for permanent disposal. The large containers now in use for dry storage remain at high temperatures for decades, thereby delaying transportation from decommissioned reactors. The large containers also have no easy path to disposal unless (1) disposal is further delayed (up to 150 years or more for some mined repository concepts); (2) the contents are repackaged into smaller, cooler packages; or (3) the high temperatures are used as de facto site-selection and design criteria for a repository. Implementing consolidated interim storage could address many issues that exist because of this lack of integration. A consolidated interim storage facility that includes appropriate capabilities can allow existing disparate parts to integrate as a system. Previous agencies and commissions have noted this theme before as a way to provide flexibility in the waste management system. This report uses the rationale for such an approach as a framework to discuss the complexities of reconfiguring the waste management system to include consolidated storage. However, concerns that increased storage capacity will reduce the national urgency for a repository are unavoidable, and continued effort will be necessary in public dialogues on the societal aspects of moving commercial spent nuclear fuel into consolidated interim storage. A single optimal solution for integrating current storage and planned transportation with disposal is unlikely. Rather, efforts to integrate various phases of spent fuel management should begin promptly and continue throughout the remaining life of the current fuel cycle. These efforts will need to adapt continuously to evolving circumstances.
Sandia National Laboratories, New Mexico (SNL/NM) is a government-owned/contractor-operated laboratory. Sandia Corporation (Sandia), a wholly owned subsidiary of Lockheed Martin Corporation, manages and operates SNL/NM for the U.S. Department of Energy (DOE), National Nuclear Security Administration (NNSA). The DOE/NNSA Sandia Field Office administers the contract and oversees contractor operations at the site. Sandia conducts two types of groundwater surveillance monitoring at SNL/NM: (1) on a site-wide basis as part of the SNL/NM Long-Term Stewardship (LTS) Program’s Groundwater Monitoring Program (GMP) Groundwater Surveillance Task and (2) as site-specific groundwater monitoring at LTS/Environmental Restoration (ER) Operations sites with ongoing groundwater investigations. This Annual Groundwater Monitoring Report summarizes data collected during groundwater monitoring events conducted at GMP locations and at the following SNL/NM sites through December 31, 2014: Burn Site Groundwater Area of Concern (AOC); Chemical Waste Landfill; Mixed Waste Landfill; Solid Waste Management Units 8/58, 49, 68, 116, 149, and 154; Technical Area-V Groundwater AOC; and the Tijeras Arroyo Groundwater AOC. Environmental monitoring and surveillance programs are required by the New Mexico Environment Department (NMED) and DOE Order 436.1, Departmental Sustainability, and DOE Order 231.1B, Environment, Safety, and Health Reporting.
Sandia National Laboratories, California (SNL/CA) is a government-owned/contractoroperated laboratory. Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, manages and operates the laboratory for the Department of Energy’s National Nuclear Security Administration (NNSA). The NNSA Sandia Field Office administers the contract and oversees contractor operations at the site. This Site Environmental Report for 2014 was prepared in accordance with DOE Order 231.1B, Environment, Safety and Health Reporting (DOE 2011d). The report provides a summary of environmental monitoring information and compliance activities that occurred at SNL/CA during calendar year 2014. General site and environmental program information is also included.
A new approach for solving Laplacian linear systems proposed by Kelner et al. involves the random sampling and update of fundamental cycles in a graph. We evaluate the performance of this approach on a variety of real world graphs. We examine di erent ways to choose the set of cycles and their sequence of updates with the goal of providing more exibility and potential parallelism. We propose a parallel model of the Kelner et al. method for evaluating potential parallelism concerned with minimizing the span of edges updated at every iteration. We provide experimental results comparing the potential parallelism of the fundamental cycle basis and the extended basis. Our preliminary experiments show that choosing a non-fundamental set of cycles can save signi cant work compared to a fundamental cycle basis.
This is to serve as verification that the Center 6200 experimental pieces supplied to the Technology Training and Demonstration Area within the Center of Global Security and Cooperation are indeed unclassified unlimited released for viewing.
A review of dosimetry results from 1 January 2010 through 31 December 2014 was conducted to demonstrate that radiation protection methods used are compliant with regulatory limits and conform to the philosophy to keep exposures to radiation As Low As is Reasonably Achievable (ALARA). This included a review and evaluation of personnel dosimetry (external and internal) results at Sandia National Laboratories, New Mexico as well as at Sandia National Laboratories, California. Additionally, results of environmental monitoring efforts at Sandia National Laboratories, New Mexico were reviewed. ALARA is a philosophical approach to radiation protection by managing and controlling radiation exposures (individual and collective) to the work force and to the general public to levels that are As Low As is Reasonably Achievable taking social, technical, economic, practical, and public policy considerations into account. ALARA is not a dose limit but a process which has the objective of attaining doses as far below applicable dose limits As Low As is Reasonably Achievable.
Numerous experiments were performed to characterize the mechanical response of several different rigid polyurethane foams (FR3712, PMDI10, PMDI20, and TufFoam35) to large deformation. In these experiments, the effects of load path, loading rate, and temperature were investigated. Results from these experiments indicated that rigid polyurethane foams exhibit significant volumetric and deviatoric plasticity when they are compressed. Rigid polyurethane foams were also found to be very strain-rate and temperature dependent. These foams are also rather brittle and crack when loaded to small strains in tension or to larger strains in compression. Thus, a new Unified Creep Plasticity Damage (UCPD) model was developed and implemented into SIERRA with the name Foam Damage to describe the mechanical response of these foams to large deformation at a variety of temperatures and strain rates. This report includes a description of recent experiments and experimental findings. Next, development of a UCPD model for rigid, polyurethane foams is described. Selection of material parameters for a variety of rigid polyurethane foams is then discussed and finite element simulations with the new UCPD model are compared with experimental results to show behavior that can be captured with this model.
The work presented in this report concerns the response and failure of thin 2024- T3 aluminum alloy circular plates to a blast load produced by the detonation of a nearby spherical charge. The plates were fully clamped around the circumference and the explosive charge was located centrally with respect to the plate. The principal objective was to conduct a numerical model validation study by comparing the results of predictions to experimental measurements of plate deformation and failure for charges with masses in the vicinity of the threshold between no tearing and tearing of the plates. Stereo digital image correlation data was acquired for all tests to measure the deflection and strains in the plates. The size of the virtual strain gage in the measurements, however, was relatively large, so the strain measurements have to be interpreted accordingly as lower bounds of the actual strains in the plate and of the severity of the strain gradients. A fully coupled interaction model between the blast and the deflection of the structure was considered. The results of the validation exercise indicated that the model predicted the deflection of the plates reasonably accurately as well as the distribution of strain on the plate. The estimation of the threshold charge based on a critical value of equivalent plastic strain measured in a bulge test, however, was not accurate. This in spite of efforts to determine the failure strain of the aluminum sheet under biaxial stress conditions. Further work is needed to be able to predict plate tearing with some degree of confidence. Given the current technology, at least one test under the actual blast conditions where the plate tears is needed to calibrate the value of equivalent plastic strain when failure occurs in the numerical model. Once that has been determined, the question of the explosive mass value at the threshold could be addressed with more confidence.
Image processing offers a potential to simplify an optical system by shifting some of the imaging burden from lenses to the more cost effective electronics. Wavefront coding using a cubic phase plate combined with image processing can extend the system's depth of focus, reducing many of the focus-related aberrations as well as material related chromatic aberrations. However, the optimal design process and physical limitations of wavefront coding systems with respect to first-order optical parameters and noise are not well documented. We examined image quality of simulated and experimental wavefront coded images before and after reconstruction in the presence of noise. Challenges in the implementation of cubic phase in an optical system are discussed. In particular, we found that limitations must be placed on system noise, aperture, field of view and bandwidth to develop a robust wavefront coded system.
Odumosu, T.B.; Tsao, Jeffrey Y.; Crabtree, G.W.; Narayanamurti, V.
The verdict is in: the methods of science can significantly enhance the effectiveness of creative teams. Just ask employers like Google and Facebook who are applying ideas from the social sciences to improve the performance of their organizations.1 Over the last few decades, social scientists, including psychologists, sociologists and anthropologists, have made important strides in developing a scientific understanding of how creative individuals and creative communities operate.
The authors, Jeffrey Y. Tsao, Jung Han, Roland H. Haitz, and P. Morgan Pattison, on behalf of a large and growing community of scientists and technologists working in III-N semiconductor materials, physics and devices, and of users of the applications they enable congratulate Professors Akasaki, Amano and Nakamura (AAN). The path that connects scientific understanding with tools and technologies is rarely linear. Prevailing scientific understanding often enables and unleashes new tools and technologies. But prevailing scientific understanding is imperfect, and technology researchers must often step, as did AAN, outside its confines for their breakthroughs. the importance of technology breakthroughs is particularly evident in semiconductors: in recent decades, more and more Physics Nobel Prizes have been awarded for technology breakthroughs, and of these by far the most have been for semiconductors.
This architecturally significant use case describes how the Analyst refines an event hypothesis. The Analyst checks waveform quality (see 'Determines Waveform Data Quality' UC). For waveforms of sufficient quality, the Analyst enhances signals and suppresses noise on waveforms for relevant stations (see 'Enhances Signals' UC), adds and associates missing detections, and modifies or unassociates detections already associated with the event hypothesis (see 'Detects Signals' UC). The Analyst rejects event hypotheses that are invalid. For valid event hypotheses, the Analyst measures signal features associated with the detections (see 'Measures Signal Features' UC) and evaluates the moment tensor ('Evaluates Moment Tensor' UC). The Analyst uses these signal features to refine the location (see 'Refines Event Location' UC) and magnitude (see 'Refines Event Magnitude' UC) of the event hypothesis. The Analyst compares events to determine how similar events were constructed (see 'Compares Events' UC). The Analyst repeats these steps until satisfied with the results. Analysts may provide feedback for previous Analysts during any of these steps (see 'Provides Analyst Feedback' UC). This use case is architecturally significant because it captures the interplay between all of the Analyst activities.
This architecturally significant use case describes how the System User observes the change history of a given event. The change history is a series of one or more saved event hypotheses. System Users view all the event hypotheses and the set of location solutions for each hypothesis. The System User views the relationship between event hypotheses including the preferred hypothesis for each processing stage. The event change history persists across work sessions for subsequent review. This use case is architecturally significant because it covers review of stored versions of event hypotheses
This architecturally significant use case describes how the Analyst compares events to determine how similar events were constructed. The Analyst compares waveforms from comparison events by visually inspecting an overlay of the waveforms to determine if the events are from a similar source. The Analyst searches for comparison events or creates agglomerative hierarchical clusters of waveforms from events and determines that the events are from a similar source if the correlation coefficient is above a selected threshold. This use case is architecturally significant due to the introduction of the capability to compare events within an operational context.
This architecturally significant use case describes how the System refines event hypothesis location solutions. The System locates events by finding the event location minimizing the difference between signal detection feature measurements and signal detection feature predictions (see 'System Measures Signal Features' UC). The System references both empirical knowledge from past events and geophysical models to form the signal detection feature predictions. The System also computes an uncertainty bound for each event hypothesis location solution describing a region bounding the event hypothesis' hypocenter and origin time at a particular confidence level. The System creates a variety of location solutions for each event hypothesis. These location solutions vary from one another in either the input parameters the System uses or in the location solution components the System restrains to fixed values (e.g. depth) during event location calculations. The System computes location solutions using input parameters configured by the System Maintainer (see ‘Configures Processing Components’ UC). The Analyst has the option to override input parameters originally configured by the System Maintainer (see 'Refines Event Location' UC). This use case is architecturally significant due to the processing and memory resource consumption of 3D earth model calculations.
The last two decades have seen an explosion in worldwide R&D, enabling fundamentally new capabilities while at the same time changing the international technology landscape. The advent of technologies for continued miniaturization and electronics feature size reduction, and for architectural innovations, will have many technical, economic, and national security implications. It is important to anticipate possible microelectronics development directions and their implications on US national interests. This report forecasts and assesses trends and directions for several potentially disruptive microfabrication capabilities and device architectures that may emerge in the next 5-10 years.