A Synthetic Aperture Radar (SAR) which employs direct IF sampling can significantly reduce the complexity of the analog electronics prior to the analog-to-digital converter (ADC). For relatively high frequency IF bands, a wide-bandwidth track-and-hold amplifier (THA) is required prior to the ADC. The THA functions primarily as a means of converting, through bandpass sampling, the IF signal to a baseband signal which can be sampled by the ADC. For a wide-band, high dynamic-range receiver system, such as a SAR receiver, stringent performance requirements are placed on the THA. We first measure the THA parameters such as gain, gain compression, third-order intercept (TOI), signal-to-noise ratio (SNR), spurious-free dynamic-range (SFDR), noise figure (NF), and phase noise. The results are then analyzed in terms of their respective impact on the overall performance of the SAR. The specific THA under consideration is the Rockwell Scientific RTH010.
This report describes a 3-D fluid mechanics code for predicting flow past bluff bodies whose surfaces can be assumed to be made up of shell elements that are simply connected. Version 1.0 of the VIPAR code (Vortex Inflation PARachute code) is described herein. This version contains several first order algorithms that we are in the process of replacing with higher order ones. These enhancements will appear in the next version of VIPAR. The present code contains a motion generator that can be used to produce a large class of rigid body motions. The present code has also been fully coupled to a structural dynamics code in which the geometry undergoes large time dependent deformations. Initial surface geometry is generated from triangular shell elements using a code such as Patran and is written into an ExodusII database file for subsequent input into VIPAR. Surface and wake variable information is output into two ExodusII files that can be post processed and viewed using software such as EnSight{trademark}.
The specific problem to be addressed in this work is the secondary combustion that arises from shock-induced mixing in volumetric explosives. It has been recognized that the effects of combustion due to secondary mixing can greatly alter the expansion of gases and dispersal of high-energy explosive. Furthermore, this enhanced effect may be a tailored feature for the new energetic material systems. One approach for studying this problem is based on the use of Large Eddy Simulation (LES) techniques. In this approach, the large turbulent length scales of motion are simulated directly while the small scales of turbulent motion are explicitly treated using a subgrid scale (SGS) model. The focus of this effort is to develop a SGS model for combustion that is applicable to shock-induced combustion events using probability density function (PDF) approaches. A simplified presumed PDF combustion model is formulated and implemented in the CTH shock physics code. Two classes of problems are studied using this model. The first is an isolated piece of reactive material burning with the surrounding air. The second problem is the dispersal of highly reactive material due to a shock driven explosion event. The results from these studies show the importance of incorporating a secondary combustion modeling capability and the utility of using a PDF-based description to simulate these events.
The lack of protection for semiconductor bridges (SCBs) against human electrostatic discharge (ESD) presents an obstacle to widespread use of this device. The goal of this research is to protect SCB initiators against pin-to-pin ESD without affecting their performance. Two techniques were investigated. In the first, a parallel capacitor is used to attenuate high frequencies. The second uses a parallel zener diode to limit the voltage amplitude. Both the 1 {micro}F capacitor and the 14 V zener diode protected the SCBs from ESD. The capacitor provided the best protection. The protection circuits had no effect on the SCB's threshold voltage. The function time for the CP-loaded SCBs with capacitors was about 11 {micro}s when fired by a firing set charged to 40 V. The SCBs failed to function when protected by the 6 V and 8 V zeners. The 51 V zener did not provide adequate protection against ESD. The parallel capacitor succeeded in protecting SCB initiators against pin-to-pin ESD without affecting their performance. Additional experiments should be done on SCBs and actual detonators to further quantify the effectiveness of this technique. Methods for retrofitting existing SCB initiators and integrating capacitors into future devices should also be explored.
This report describes the PDF Object Linking Extension (POLE) and how it came about. POLE is an extension of an existing DXL script called Outdoors that provides a linking mechanism to files outside of DOORS. Our modifications expand the script's capabilities to link to bookmarks within PDF documents. PDF linking allows for traceability to be maintained between DOORS objects and the requirements within PDF files.
Foliage penetrating (FOPEN) synthetic aperture radar (SAR) systems are capable of producing images of targets concealed under a foliage canopy. The quality and interpretability of these images, however, is generally limited by dense foliage clutter and by fundamental foliage-induced image degradation. Use of a polarimetric SAR to provide multiple polarization channels can mitigate these effects by offering target and scene information beyond that provided by a single-polarization SAR. This paper presents the results of a literature survey to investigate the use of multiple-polarization data in conjunction with FOPEN SAR applications. The effects of foliage propagation on SAR image quality are briefly summarized. Various approaches to multiple-polarization-based FOPEN target detection are described. Although literature concerning FOPEN target recognition is scarce, the use of multiple-polarization data for in-the-clear target recognition is described. The applicability of various target detection and recognition applications for use with concealed target SAR (CTSAR) imagery is considered.
The goal of this LDRD was to engineer further improvements in a novel electron tunneling device, the double electron layer tunneling transistor (DELTT). The DELTT is a three terminal quantum device, which does not require lateral depletion or lateral confinement, but rather is entirely planar in configuration. The DELTT's operation is based on 2D-2D tunneling between two parallel 2D electron layers in a semiconductor double quantum well heterostructure. The only critical dimensions reside in the growth direction, thus taking full advantage of the single atomic layer resolution of existing semiconductor growth techniques such as molecular beam epitaxy. Despite these advances, the original DELTT design suffered from a number of performance short comings that would need to be overcome for practical applications. These included (i)a peak voltage too low ({approx}20 mV) to interface with conventional electronics and to be robust against environmental noise, (ii) a low peak current density, (iii) a relatively weak dependence of the peak voltage on applied gate voltage, and (iv) an operating temperature that, while fairly high, remained below room temperature. In this LDRD we designed and demonstrated an advanced resonant tunneling transistor that incorporates structural elements both of the DELTT and of conventional double barrier resonant tunneling diodes (RTDs). Specifically, the device is similar to the DELTT in that it is based on 2D-2D tunneling and is controlled by a surface gate, yet is also similar to the RTD in that it has a double barrier structure and a third collector region. Indeed, the device may be thought of either as an RTD with a gate-controlled, fully 2D emitter, or alternatively, as a ''3-layer DELTT,'' the name we have chosen for the device. This new resonant tunneling transistor retains the original DELTT advantages of a planar geometry and sharp 2D-2D tunneling characteristics, yet also overcomes the performance shortcomings of the original DELTT design. In particular, it exhibits the high peak voltages and current densities associated with conventional RTDs, allows sensitive control of the peak voltage by the control gate, and operates nearly at room temperature. Finally, we note under this LDRD we also investigated the use of three layer DELTT structures as long wavelength (Terahertz) detectors using photon-assisted tunneling. We have recently observed a narrowband (resonant) tunable photoresponse in related structures consisting of grating-gated double quantum wells, and report on that work here as well.
Sandia National Laboratories has developed a Near Real Time Range Safety Analysis Tool named PREDICT that is based upon a probabilistic range safety analysis process. Probabilistic calculations of risk may be used in place of the total containment of potentially hazardous debris during a missile launch operation. Impact probabilities are computed based upon probabilistic density functions, Monte Carlo trajectories of dispersion events, and missile failure scenarios. Impact probabilities are then coupled with current demographics (land populations, commercial and military ship traffic, and aircraft traffic) to produce expected casualty predictions for a particular launch window. Historically, these calculations required days of computer time to finalize. Sandia has developed a process that utilizes the IBM SP machines at the Maui High Performance Computing Center and at the Arctic Region Supercomputing Center to reduce the computation time from days to as little as an hour or two. This analysis tool then allows the Missile Flight Safety Officer to make launch decisions based on the latest information (winds, ship, and aircraft movements) utilizing an intelligent risk management approach. This report provides a user's manual for PREDICT version 3.3.
The highly leveraged, asymmetric attacks of September 11th have launched the nation on a vast ''War on Terrorism''. Now that our vulnerabilities and the enemies' objectives and determination have been demonstrated, we find ourselves rapidly immersed in a huge, complex problem that is virtually devoid of true understanding while being swamped with resources and proposed technologies for solutions. How do we win this war? How do we make sure that we are making the proper investments? What things or freedoms or rights do we have to give up to win? Where do we even start? In analyzing this problem, many similarities to mankind's battle with uncontrolled fire and the threat it presented to society were noted. Major fires throughout history have destroyed whole cities and caused massive loss of life and property. Solutions were devised that have gradually, over several hundred years, reduced this threat to a level that allows us to co-exist with the threat of fire by applying constant vigilance and investments in fire protection, but without living in constant fear and dread from fire. We have created a multi-pronged approach to fire protection that involves both government and individuals in the prevention, mitigation, and response to fires. Fire protection has become a virtually unnoticed constant in our daily lives; we will have to do the same for terrorism. This paper discusses the history of fire protection and draws analogies to our War on Terrorism. We have, as a society, tackled and successfully conquered a problem as big as terrorism. From this battle, we can learn and take comfort.
Arsenic removal technologies that are effective at the tens of ppb level include coagulation, followed by settling/microfiltration, ion exchange by mineral surfaces,and pressure-driven membrane processes (reverse osmosis, nanofiltration and ultrafiltration). This report describes the fundamental mechanisms of operation of the arsenic removal systems and addresses the critical issues of arsenic speciation, source water quality on the performance of the arsenic removal systems and costs associated with the different treatment technology categories.
This report describes the results of research and development in the area of communication among disparate species of software agents. The two primary elements of the work are the formation of ontologies for use by software agents and the means by which software agents are instructed to carry out complex tasks that require interaction with other agents. This work was grounded in the areas of commercial transport and cybersecurity.
The development and testing of a new technique for blending of electrolyte-binder (separator) mixes for use in thermal batteries is described. The original method of blending such materials at Sandia involved liquid Freon TF' as a medium. The ban on the use of halogenated solvents throughout much of the Department of Energy complex required the development of an alternative liquid medium as a replacement. The use of liquid nitrogen (LN) was explored and developed into a viable quality process. For comparison, a limited number of dry-blending tests were also conducted using a Turbula mixer. The characterization of pellets made from LN-blended separators involved deformation properties at 530 C and electrolyte-leakage behavior at 400 or 500 C, as well as performance in single-cells and five-cell batteries under several loads. Stack-relaxation tests were also conducted using 10-cell batteries. One objective of this work was to observe if correlations could be obtained between the mechanical properties of the separators and the performance in single cells and batteries. Separators made using three different electrolytes were examined in this study. These included the LiCl-KCl eutectic, the all-Li LiCl-LiBr-LiF electrolyte, and the low-melting LiBr-KBr-LiF eutectic. The electrochemical performance of separator pellets made with LN-blended materials was compared to that for those made with Freon T P and, in some cases, those that were dry blended. A satisfactory replacement MgO (Marinco 'OL', now manufactured by Morton) was qualified as a replacement for the standard Maglite 'S' MgO that has been used for years but is no longer commercially available. The separator compositions with the new MgO were optimized and included in the blending and electrochemical characterization tests.
Many governmental and corporate organizations are interested in tracking materials and/or information through a network. Often, as in the case of the U.S. Customs Service, the traffic is recorded as transactions through a large number of checkpoints with a correspondingly complex network. These networks will contain large numbers of uninteresting transactions that act as noise to conceal the chains of transactions of interest, such as drug trafficking. We are interested in finding significant paths in transaction data containing high noise levels, which tend to make traditional graph visualization methods complex and hard to understand. This paper covers the evolution of a series of graphing methods designed to assist in this search for paths-from 1-D to 2-D to 3-D and beyond.
Endospores of the bacterium, Bacillus subfilis, have been shown to exhibit a synergistic rate of cell death when treated with particular levels of heat and ionizing radiation in combination. This synergism has been documented for a number of different organisms at various temperatures and radiation doses (Sivinski, H.D., D.M. Garst, M.C. Reynolds, C.A. Trauth, Jr., R.E. Trujillo, and W.J. Whitfield, ''The Synergistic Inactivation of Biological Systems by Thermoradiation,'' Industrial Sterilization, International Symposium, Amsterdam, 1972, Duke University Press, Durham, NC, pp. 305-335). However, the mechanism of the synergistic action is unknown. This study attempted to determine whether the mechanism of synergism was specifically connected to the DNA strand breakage--either single strand breakage or double strand breakage. Some work was also done to examine the effect of free radicals and ions created in the spore body by the radiation treatments, as well as to determine the functionality of repair enzymes following heat, radiation, and thermoradiation treatments. Bacillus subtilis spores were treated at combinations of 33 kr/hr, 15 kr/hr, 105 C, 85 C, 63 C, and 50 C. Some synergistic correlation was found with the number of double strand breaks, and a strong correlation was found with the number of single strand breaks. In cases displaying synergism of spore killing, single strand breakage while the DNA was in a denatured state is suspected as a likely mechanism. DNA was damaged more by irradiation in the naked state than when encased within the spore, indicating that the spore encasement provides an overall protective effect from radiation damage in spite of free radicals and ions which may be created from molecules other than the DNA molecule within the spore body. Repair enzymes were found to be functional following treatments by radiation only, heat only, and thermoradiation.
Photovoltaics is the utility connected distributed energy resource (DER) that is in widespread use today. It has one element, the inverter, which is common with all DER sources except rotating generators. The inverter is required to transfer dc energy to ac energy. With all the DER technologies, (solar, wind, fuel cells, and microturbines) the inverter is still an immature product that will result in reliability problems in fielded systems. Today, the PV inverter is a costly and complex component of PV systems that produce ac power. Inverter MTFF (mean time to first failure) is currently unacceptable. Low inverter reliability contributes to unreliable fielded systems and a loss of confidence in renewable technology. The low volume of PV inverters produced restricts the manufacturing to small suppliers without sophisticated research and reliability programs or manufacturing methods. Thus, the present approach to PV inverter supply has low probability of meeting DOE reliability goals. DOE investments in power electronics are intended to address the reliability and cost of power electronics. This report details the progress of power electronics, identifies technologies that are in current use, and explores new approaches that can provide significant improvements in inverter reliability while leading to lower cost. A key element to improved inverter design is the systems approach to design. This approach includes a list of requirements for the product being designed and a preliminary requirements document is a part of this report. Finally, the design will be for a universal inverter that can be applied to several technologies. The objective of a universal inverter is to increase the quantity being manufactured so that mass-manufacturing techniques can be applied. The report includes the requirements and recommended design approaches for a new inverter with a ten-year mean time to first failure (MTFF) and with lower cost. This development will constitute a ''leap forward'' in capability that leverages emerging technologies and best manufacturing processes to produce a new, high reliability, inverter. The targeted inverter size is from two to ten kilowatts. The report is organized into four sections. A brief introduction by Sandia is followed by Section Two from Millennium Technologies (a company with UPS experience). Section Three is provided by Xantrex (a PV manufacturing company) and the University of Minnesota provided Section Four. This report is very detailed and provides inverter design information that is irrelevant to the layman. It is intended to be a comprehensive documentation of proven technology and the manufacturing skills required to produce a high reliability inverter. An accompanying report will provide a summary of the recommended approach for inverter development.
Since 1983, ground surface elevation data from the US DOE West Hackberry Strategic Petroleum crude oil storage facility has been routinely collected. The data have been assimilated, analyzed, and presented in terms of absolute elevations, subsidence rate, and estimates of volumetric changes of the storage facility. The information presented impacts operations and maintenance of the facility, and provides important constraints on the interpretation of ongoing structural analyses of the facility.
The Strategic Petroleum Reserve site at West Hackberry, Louisiana has historically experienced casing leaks. Numerous West Hackberry oil storage caverns have wells exhibiting communication between the interior 10 3/4 x 20-inch (oil) annulus and the ''outer cemented'' 20 x 26-inch annulus. Well 108 in Cavern 108 exhibits this behavior. It is thought that one, if not the primary, cause of this communication is casing thread leaks at the 20-inch casing joints combined with microannuli along the cement casing interfaces and other cracks/flaws in the cemented 20 x 26-inch annulus. An operation consisting of a series of nitrogen leak tests, similar to cavern integrity tests, was performed on Cavern 108 in an effort to determine the leak horizons and to see if these leak horizons coincided with those of casing joints. Certain leaky, threaded casing joints were identified between 400 and 1500 feet. A new leak detection procedure was developed as a result of this test, and this methodology for identifying and interpreting such casing joint leaks is presented in this report. Analysis of the test data showed that individual joint leaks could be successfully identified, but not without some degree of ambiguity. This ambiguity is attributed to changes in the fluid content of the leak path (nitrogen forcing out oil) and possibly to very plausible changes in characteristics of the flow path during the test. These changes dominated the test response and made the identification of individual leak horizons difficult. One consequence of concern from the testing was a progressive increase in the leak rate measured during testing due to nitrogen cleaning small amounts of oil out of the leak paths and very likely due to the changes of the leak path during the flow test. Therefore, careful consideration must be given before attempting similar tests. Although such leaks have caused no known environmental or economic problems to date, the leaks may be significant because of the potential for future problems. To mitigate future problems, some repair scenarios are discussed including injection of sealants.
This report describes a new microsystems technology for the creation of microsensors and microelectromechanical systems (MEMS) using stress-free amorphous diamond (aD) films. Stress-free aD is a new material that has mechanical properties close to that of crystalline diamond, and the material is particularly promising for the development of high sensitivity microsensors and rugged and reliable MEMS. Some of the unique properties of aD include the ability to easily tailor film stress from compressive to slightly tensile, hardness and stiffness 80-90% that of crystalline diamond, very high wear resistance, a hydrophobic surface, extreme chemical inertness, chemical compatibility with silicon, controllable electrical conductivity from insulating to conducting, and biocompatibility. A variety of MEMS structures were fabricated from this material and evaluated. These structures included electrostatically-actuated comb drives, micro-tensile test structures, singly- and doubly-clamped beams, and friction and wear test structures. It was found that surface micromachined MEMS could be fabricated in this material easily and that the hydrophobic surface of the film enabled the release of structures without the need for special drying procedures or the use of applied hydrophobic coatings. Measurements using these structures revealed that aD has a Young's modulus of {approx}650 GPa, a tensile fracture strength of 8 GPa, and a fracture toughness of 8 MPa{center_dot}m {sup 1/2}. These results suggest that this material may be suitable in applications where stiction or wear is an issue. Flexural plate wave (FPW) microsensors were also fabricated from aD. These devices use membranes of aD as thin as {approx}100 nm. The performance of the aD FPW sensors was evaluated for the detection of volatile organic compounds using ethyl cellulose as the sensor coating. For comparable membrane thicknesses, the aD sensors showed better performance than silicon nitride based sensors. Greater than one order of magnitude increase in chemical sensitivity is expected through the use of ultra-thin aD membranes in the FPW sensor. The discoveries and development of the aD microsystems technology that were made in this project have led to new research projects in the areas of aD bioMEMS and aD radio frequency MEMS.
Photon radiation transport is described by the Boltzmann equation. Because this equation is difficult to solve, many different approximate forms have been implemented in computer codes. Several of the most common approximations are reviewed, and test problems illustrate the characteristics of each of the approximations. This document is designed as a tutorial so that code users can make an educated choice about which form of approximate radiation transport to use for their particular simulation.
This activity brought two robotic mobile manipulation systems developed by Sandia National Laboratories to the Maneuver Support Center (MANSCEN) at Ft. Leonard Wood for the following purposes: Demonstrate advanced manipulation and control capabilities; Apply manipulation to hazardous activities within MANSCEN mission space; Stimulate thought and identify potential applications for future mobile manipulation applications; and Provide introductory knowledge of manipulation to better understand how to specify capability and write requirements.
This report summarizes the work completed in the MyLink Lab Directed Research and Development project. The goal of this project was to investigate the ability of computers to come to understand individuals and to assist them with various aspects of their lives.
The conventional discrete ordinates approximation to the Boltzmann transport equation can be described in a matrix form. Specifically, the within-group scattering integral can be represented by three components: a moment-to-discrete matrix, a scattering cross-section matrix and a discrete-to-moment matrix. Using and extending these entities, we derive and summarize the matrix representations of the second-order transport equations.
This document is the second in a series that describe graphical user interface tools developed to control the Visual Empirical Region of Influence (VERI) algorithm. In this paper we describe a user interface designed to optimize the VERI algorithm results. The optimization mode uses a brute force method of searching through the combinations of features in a data set for features that produce the best pattern recognition results. With a small number of features in a data set an exact solution can be determined. However, the number of possible combinations increases exponentially with the number of features and an alternate means of finding a solution must be found. We developed and implemented a technique for finding solutions in data sets with both small and large numbers of features. This document illustrates step-by-step examples of how to use the interface and how to interpret the results. It is written in two parts, part I deals with using the interface to find the best combination from all possible sets of features, part II describes how to use the tool to find a good solution in data sets with a large number of features. The VERI Optimization Interface Tool was written using the Tcl/Tk Graphical User Interface (GUI) programming language, version 8.1. Although the Tcl/Tk packages are designed to run on multiple computer platforms, we have concentrated our efforts to develop a user interface for the ubiquitous DOS environment. The VERI algorithms are compiled, executable programs. The optimization interface executes the VERI algorithm in Leave-One-Out mode using the Euclidean metric. For a thorough description of the type of data analysis we perform, and for a general Pattern Recognition tutorial, refer to our website at: http://www.sandia.gov/imrl/XVisionScience/Xusers.htm.
A laser safety evaluation and pertinent output measurements were performed (during March and April 2002) on the M203PI Grenade Launcher Simulator (GLS) and its associated Umpire Control Gun manufactured by Oscmar International Limited, Auckland, New Zealand. The results were the Oscmar Umpire Gun is laser hazard Class 1 and can be used without restrictions. The radiant energy output of the Oscmar M203PI GLS, under ''Small Source'' criteria at 10 centimeters, is laser hazard Class 3b and not usable, under SNL policy, in force-on-force exercises. However, due to a relatively large exit diameter and an intentionally large beam divergence, to simulate a large area blast, the output beam geometry met the criteria for ''Extended Source'' viewing [ANSI Std. 2136.1-2000 (S.l)]. Under this ''Extended Source'' criteria the output of the M203PI GLS unit was, in fact, laser hazard Class 1 (eye safe), for 3 of the 4 possible modes of laser operation. The 4'h mode, ''Auto Fire'', which simulates a continuous grenade firing every second and is not used at SNL, was laser hazard Class 3a (under the ''Extended Source'' viewing criteria). The M203PI GLS does present a laser hazard Class 3a to aided viewing with binoculars inside 3 meters from the unit. Farther than 3 meters it is ''eye safe''. The M203PI GLS can be considered a Class 1 laser hazard and can be used under SNL policy with the following restrictions: (1) The M203PI GLS unit shall only be programmed for: the ''Single Fire'' (which, includes ''Rapid Fire'') and the ''Auto Align'' (used in adjusting the alignment of the grenade launcher simulator system to the target) modes of operation. (2) The M203PI GLS shall never be directed against personnel, using binoculars, inside of 3 meters. DOE Order 5480.16A, Firearms Safety, (Chapter 1)(5)(a)(8)(d) and DOE-STD-1091-96, Firearms Safety (Chapter 4); already prevents ESS laser engagement of personnel (with or without binoculars), ''closer than 10 feet (3.05 meters)''. Both of these restrictions can be administratively imposed, through a formal Operating Procedure or Technical Work Document and by full compliance with DOE orders and standards.
This project makes use of ''biomimetic behavioral engineering'' in which adaptive strategies used by animals in the real world are applied to the development of autonomous robots. The key elements of the biomimetic approach are to observe and understand a survival behavior exhibited in nature, to create a mathematical model and simulation capability for that behavior, to modify and optimize the behavior for a desired robotics application, and to implement it. The application described in this report is dynamic soaring, a behavior that certain sea birds use to extract flight energy from laminar wind velocity gradients in the shallow atmospheric boundary layer directly above the ocean surface. Theoretical calculations, computational proof-of-principle demonstrations, and the first instrumented experimental flight test data for dynamic soaring are presented to address the feasibility of developing dynamic soaring flight control algorithms to sustain the flight of unmanned airborne vehicles (UAVs). Both hardware and software were developed for this application. Eight-foot custom foam sailplanes were built and flown in a steep shear gradient. A logging device was designed and constructed with custom software to record flight data during dynamic soaring maneuvers. A computational toolkit was developed to simulate dynamic soaring in special cases and with a full 6-degree of freedom flight dynamics model in a generalized time-dependent wind field. Several 3-dimensional visualization tools were built to replay the flight simulations. A realistic aerodynamics model of an eight-foot sailplane was developed using measured aerodynamic derivatives. Genetic programming methods were developed and linked to the simulations and visualization tools. These tools can now be generalized for other biomimetic behavior applications.
Historically, high resolution, high slew rate optics have been heavy, bulky, and expensive. Recent advances in MEMS (Micro Electro Mechanical Systems) technology and micro-machining may change this. Specifically, the advent of steerable sub-millimeter sized mirror arrays could provide the breakthrough technology for producing very small-scale high-performance optical systems. For example, an array of steerable MEMS mirrors could be the building blocks for a Fresnel mirror of controllable focal length and direction of view. When coupled with a convex parabolic mirror the steerable array could realize a micro-scale pan, tilt and zoom system that provides full CCD sensor resolution over the desired field of view with no moving parts (other than MEMS elements). This LDRD provided the first steps towards the goal of a new class of small-scale high-performance optics based on MEMS technology. A large-scale, proof of concept system was built to demonstrate the effectiveness of an optical configuration applicable to producing a small-scale (< 1cm) pan and tilt imaging system. This configuration consists of a color CCD imager with a narrow field of view lens, a steerable flat mirror, and a convex parabolic mirror. The steerable flat mirror directs the camera's narrow field of view to small areas of the convex mirror providing much higher pixel density in the region of interest than is possible with a full 360 deg. imaging system. Improved image correction (dewarping) software based on texture mapping images to geometric solids was developed. This approach takes advantage of modern graphics hardware and provides a great deal of flexibility for correcting images from various mirror shapes. An analytical evaluation of blur spot size and axi-symmetric reflector optimization were performed to address depth of focus issues that occurred in the proof of concept system. The resulting equations will provide the tools for developing future system designs.
GENESIS Version 2.0 is a general circulation model developed at the National Center for Atmospheric Research (NCAR) and is the principal code that is used by paleoclimatologists to model climate at various times throughout Earth's history. The primary result of this LDRD project has been the development of a distributed-memory parallel version of GENESIS, leading to a significant performance enhancement on commodity-based, large-scale computing platforms like the CPlant. The shared-memory directives of the original version were replaced by MPI calls in the new version of GENESIS. This was accomplished by means of parallel decomposition over latitude strip domains. The code achieved a parallel speedup of four times that of the shared-memory parallel version at R15 resolution. T106 resolution runs 20 times faster than the NCAR serial version on 20 nodes of the CPlant. As part of the project, GENESIS was used to model the climatic effects of an orbiting debris ring due to a large planetary impact event.
Electro-microfluidics is experiencing explosive growth in new product developments. There are many commercial applications for electro-microfluidic devices such as chemical sensors, biological sensors, and drop ejectors for both printing and chemical analysis. The number of silicon surface micromachined electro-microfluidic products is likely to increase. Manufacturing efficiency and integration of microfluidics with electronics will become important. Surface micromachined microfluidic devices are manufactured with the same tools as IC's (integrated circuits) and their fabrication can be incorporated into the IC fabrication process. In order to realize applications for devices must be developed. An Electro-Microfluidic Dual In-line Package (EMDIP{trademark}) was developed surface micromachined electro-microfluidic devices, a practical method for getting fluid into these to be a standard solution that allows for both the electrical and the fluidic connections needed to operate a great variety of electro-microfluidic devices. The EMDIP{trademark} includes a fan-out manifold that, on one side, mates directly with the 200 micron diameter Bosch etched holes found on the device, and, on the other side, mates to lager 1 mm diameter holes. To minimize cost the EMDIP{trademark} can be injection molded in a great variety of thermoplastics which also serve to optimize fluid compatibility. The EMDIP{trademark} plugs directly into a fluidic printed wiring board using a standard dual in-line package pattern for the electrical connections and having a grid of multiple 1 mm diameter fluidic connections to mate to the underside of the EMDIP{trademark}.
The information form of the Kalman filter is used as a device for implementing an optimal, linear, decentralized algorithm on a decentralized topology. A systems approach utilizing design tradeoffs is required to successfully implement an effective data fusion network with minimal communication. Combining decentralized results over the past four decades with practical aspects of nodal network implementation, the final product provides an important benchmark for functionally decentralized systems designs.
Inorganic mesoporous thin-films are import for applications such as membranes, sensors, low-dielectric-constant insulators (so-called low {kappa} dielectrics), and fluidic devices. Over the past five years, several research groups have demonstrated the efficacy of using evaporation accompanying conventional coating operations such as spin- and dip-coating as an efficient means of driving the self-assembly of homogeneous solutions into highly ordered, oriented, mesostructured films. Understanding such evaporation-induced self-assembly (EISA) processes is of interest for both fundamental and technological reasons. Here, the authors use spatially resolved 2D grazing incidence X-ray scattering in combination with optical interferometry during steady-state dip-coating of surfactant-templated silica thin-films to structurally and compositionally characterize the EISA process. They report the evolution of a hexagonal (p6 mm) thin-film mesophase from a homogeneous precursor solution and its further structural development during drying and calcination. Monte Carlo simulations of water/ethanol/surfactant bulk phase behavior are used to investigate the role of ethanol in the self-assembly process, and they propose a mechanism to explain the observed dilation in unit cell dimensions during solvent evaporation.
An approach is presented to compute the force on a spherical particle in a rarefied flow of a monatomic gas. This approach relies on the development of a Green's function that describes the force on a spherical particle in a delta-function molecular velocity distribution function. The gas-surface interaction model in this development allows incomplete accommodation of energy and tangential momentum. The force from an arbitrary molecular velocity distribution is calculated by computing the moment of the force Green's function in the same way that other macroscopic variables are determined. Since the molecular velocity distribution function is directly determined in the DSMC method, the force Green's function approach can be implemented straightforwardly in DSMC codes. A similar approach yields the heat transfer to a spherical particle in a rarefied gas flow. The force Green's function is demonstrated by application to two problems. First, the drag force on a spherical particle at arbitrary temperature and moving at arbitrary velocity through an equilibrium motionless gas is found analytically and numerically. Second, the thermophoretic force on a motionless particle in a motionless gas with a heat flux is found analytically and numerically. Good agreement is observed in both situations.
In this report we describe the construction and characterization of a small quantum processor based on trapped ions. This processor could ultimately be used to perform analogue quantum simulations with an engineered computationally-cold bath for increasing the system's robustness to noise. We outline the requirements to build such a simulator, including individual addressing, distinguishable detection, and low crosstalk between operations, and our methods to implement and characterize these requirements. Specifically for measuring crosstalk, we introduce a new method, simultaneous gate set tomography to characterize crosstalk errors.
The original DAMP (W t a Manipulation Program) was written by Mark Hedemann of Sandia National Laboratories and used the CA-DISSPLA{trademark} (available from Computer Associates International, Inc., Garden City, NY) graphics package as its engine. It was used to plot, modify, and otherwise manipulate the one-dimensional data waveforms (data vs. time) from a wide variety of accelerators. With the waning of CA-DISSPLA and the increasing popularity of Unix{reg_sign}-based workstations, a replacement was needed. This package uses the IDL{reg_sign} software, available from Research Systems Incorporated, a Xerox company, in Boulder, Colorado, as the engine, and creates a set of widgets to manipulate the data in a manner similar to the original DAMP and earlier versions of xdamp. IDL is currently supported on a wide variety of Unix platforms such as IBM{reg_sign} workstations, Hewlett Packard workstations, SUN{reg_sign} workstations, Microsoft{reg_sign} Windows{trademark} computers, Macintosh{reg_sign} computers and Digital Equipment Corporation VMS{reg_sign} and Alpha{reg_sign} systems. Thus, xdamp is portable across many platforms. We have verified operation, albeit with some minor IDL bugs, on personal computers using Windows 95 and Windows NT; IBM Unix platforms; DEC Alpha and VMS systems; HP 9000/700 series workstations; and Macintosh computers, both regular and PowerPC{trademark} versions. Version 4 is an update that removes some obsolete features and better supports very large arrays and Excel formatted data import.
Mine detection dogs have a demonstrated capability to locate hidden objects by trace chemical detection. Because of this capability, demining activities frequently employ mine detection dogs to locate individual buried landmines or for area reduction. The conditions appropriate for use of mine detection dogs are only beginning to emerge through diligent research that combines dog selection/training, the environmental conditions that impact landmine signature chemical vapors, and vapor sensing performance capability and reliability. This report seeks to address the fundamental soil-chemical interactions, driven by local weather history, that influence the availability of chemical for trace chemical detection. The processes evaluated include: landmine chemical emissions to the soil, chemical distribution in soils, chemical degradation in soils, and weather and chemical transport in soils. Simulation modeling is presented as a method to evaluate the complex interdependencies among these various processes and to establish conditions appropriate for trace chemical detection. Results from chemical analyses on soil samples obtained adjacent to landmines are presented and demonstrate the ultra-trace nature of these residues. Lastly, initial measurements of the vapor sensing performance of mine detection dogs demonstrates the extreme sensitivity of dogs in sensing landmine signature chemicals; however, reliability at these ultra-trace vapor concentrations still needs to be determined. Through this compilation, additional work is suggested that will fill in data gaps to improve the utility of trace chemical detection.
The purpose of the report is to summarize discussions from a Ceramic/Metal Brazing: From Fundamentals to Applications Workshop that was held at Sandia National Laboratories in Albuquerque, NM on April 4, 2001. Brazing experts and users who bridge common areas of research, design, and manufacturing participated in the exercise. External perspectives on the general state of the science and technology for ceramics and metal brazing were given. Other discussions highlighted and critiqued Sandia's brazing research and engineering programs, including the latest advances in braze modeling and materials characterization. The workshop concluded with a facilitated dialogue that identified critical brazing research needs and opportunities.
This report provides a review of the open literature relating to numerical methods for simulating deep penetration events. The objective of this review is to provide recommendations for future development of the ALEGRA shock physics code to support earth penetrating weapon applications. While this report focuses on coupled Eulerian-Lagrangian methods, a number of complementary methods are also discussed which warrant further investigation. Several recommendations are made for development activities within ALEGRA to support earth penetrating weapon applications in the short, intermediate, and long term.
The quality of low-cost multicrystalline silicon (mc-Si) has improved to the point that it forms approximately 50% of the worldwide photovoltaic (PV) power production. The performance of commercial mc-Si solar cells still lags behind c-Si due in part to the inability to texture it effectively and inexpensively. Surface texturing of mc-Si has been an active field of research. Several techniques including anodic etching [1], wet acidic etching [2], lithographic patterning [3], and mechanical texturing [4] have been investigated with varying degrees of success. To date, a cost-effective technique has not emerged.
This report summarizes the activities of the Computer Science Research Institute at Sandia National Laboratories during the period January 1, 2001 to December 31, 2001.
This study on the opportunities for energy storage technologies determined electric utility application requirements, assessed the suitability of a variety of storage technologies to meet the requirements, and reviewed the compatibility of technologies to satisfy multiple applications in individual installations. The study is called ''Opportunities Analysis'' because it identified the most promising opportunities for the implementation of energy storage technologies in stationary applications. The study was sponsored by the U.S. DOE Energy Storage Systems Program through Sandia National Laboratories and was performed in coordination with industry experts from utilities, manufacturers, and research organizations. This Phase II report updates the Phase I analysis performed in 1994.
A new concept has been developed which allows direct-to-RF conversion of digitally synthesized waveforms. The concept named Quadrature Error Corrected Digital Waveform Synthesis (QECDWS) employs quadrature amplitude and phase predistortion to the complex waveform to reduce the undesirable quadrature image. Another undesirable product of QECDWS-based RF conversion is the Local Oscillator (LO) leakage through the quadrature upconverter (mixer). A common technique for reducing this LO leakage is to apply a quadrature bias to the mixer I and Q inputs. This report analyzes this technique through theory, lab measurement, and data analysis for a candidate quadrature mixer for Synthetic Aperture Radar (SAR) applications.
Biomass feedstocks contain roughly 10-30% lignin, a substance that can not be converted to fermentable sugars. Hence, most schemes for producing biofuels (ethanol) assume that the lignin coproduct will be utilized as boiler fuel to provide heat and power to the process. However, the chemical structure of lignin suggests that it will make an excellent high value fuel additive, if it can be broken down into smaller molecular units. From fiscal year 1997 through fiscal year 2001, Sandia National Laboratories was a participant in a cooperative effort with the National Renewable Energy Laboratory and the University of Utah to develop and scale a base catalyzed depolymerization (BCD) process for lignin conversion. SNL's primary role in the effort was to utilize rapidly heated batch microreactors to perform kinetic studies, examine the reaction chemistry, and to develop alternate catalyst systems for the BCD process. This report summarizes the work performed at Sandia during FY97 and FY98 with alcohol based systems. More recent work with aqueous based systems will be summarized in a second report.