Nowadays composite materials have been extensively utilized in many military and industrial applications. For example, the newest Boeing 787 uses 50% composite (mostly carbon fiber reinforced plastic) in production. However, the weak delamination strength of fiber reinforced composites, when subjected to external impact such as ballistic impact, has been always potential serious threats to the safety of passengers. Dynamic fracture toughness is a critical indicator of the performance from delamination in such impact events. Quasi-static experimental techniques for fracture toughness have been well developed. For example, end notched flexure (ENF) technique, which is illustrated in Fig. 1, has become a typical method to determined mode-II fracture toughness for composites under quasi-static loading conditions. However, dynamic fracture characterization of composites has been challenging. This has resulted in conflictive and confusing conclusions in regard to strain rate effects on fracture toughness of composites.
Liquid foams are viscoelastic liquids, exhibiting a fast relaxation attributed to local bubble motions and a slow response due to structural evolution of the intrinsically unstable system. In this work, these processes are examined in unique organic foams that differ from the typically investigated aqueous systems in two major ways: the organic foams (1) posses a much higher continuous phase viscosity and (2) exhibit a coarsening response that involves coalescence of cells. The transient and dynamic relaxation responses of the organic foams are evaluated and discussed in relation to the response of aqueous foams. The change in the foam response with increasing gas fraction, from that of a Newtonian liquid to one that is strongly viscoelastic, is also presented. In addition, the temporal dependencies of the linear viscoelastic response are assessed in the context of the foam structural evolution. These foams and characterization techniques provide a basis for testing stabilization mechanisms in epoxy-based foams for encapsulation applications.
Alkali nitrate eutectic mixtures are finding application as industrial heat transfer fluids in concentrated solar power generation systems. An important property for such applications is the melting point, or phase coexistence temperature. We have computed melting points for lithium, sodium and potassium nitrate from molecular dynamics simulations using a recently developed method, which uses thermodynamic integration to compute the free energy difference between the solid and liquid phases. The computed melting point for NaNO3 was within 15K of its experimental value, while for LiNO3 and KNO3, the computed melting points were within 100K of the experimental values [4]. We are currently extending the approach to calculate melting temperatures for binary mixtures of lithium and sodium nitrate.
The annual program report provides detailed information about all aspects of the SNL/CA Pollution Prevention Program for a given calendar year. It functions as supporting documentation to the SNL/CA Environmental Management System Program Manual. The program report describes the activities undertaken during the past year, and activities planned in future years to implement the Pollution Prevention Program, one of six programs that supports environmental management at SNL/CA.
Development of silicon, enhancement mode nanostructures for solid-state quantum computing will be described. A primary motivation of this research is the recent unprecedented manipulation of single electron spins in GaAs quantum dots, which has been used to demonstrate a quantum bit. Long spin decoherence times are predicted possible in silicon qubits. This talk will focus on silicon enhancement mode quantum dot structures that emulate the GaAs lateral quantum dot qubit but use an enhancement mode field effect transistor (FET) structure. One critical concern for silicon quantum dots that use oxides as insulators in the FET structure is that defects in the metal oxide semiconductor (MOS) stack can produce both detrimental electrostatic and paramagnetic effects on the qubit. Understanding the implications of defects in the Si MOS system is also relevant for other qubit architectures that have nearby dielectric passivated surfaces. Stable, lithographically defined, single-period Coulomb-blockade and single-electron charge sensing in a quantum dot nanostructure using a MOS stack will be presented. A combination of characterization of defects, modeling and consideration of modified approaches that incorporate SiGe or donors provides guidance about the enhancement mode MOS approach for future qubits and quantum circuit micro-architecture.
The microscopic Polymer Reference Interaction Site Model theory has been applied to spherical and rodlike fillers dissolved in three types of chemically heterogeneous polymer melts: alternating AB copolymer, random AB copolymers, and an equimolar blend of two homopolymers. In each case, one monomer species adsorbs more strongly on the filler mimicking a specific attraction, while all inter-monomer potentials are hard core which precludes macrophase or microphase separation. Qualitative differences in the filler potential-of-mean force are predicted relative to the homopolymer case. The adsorbed bound layer for alternating copolymers exhibits a spatial moduluation or layering effect but is otherwise similar to that of the homopolymer system. Random copolymers and the polymer blend mediate a novel strong, long-range bridging interaction between fillers at moderate to high adsorption strengths. The bridging strength is a non-monotonic function of random copolymer composition, reflecting subtle competing enthalpic and entropic considerations.
The low-energy properties of the Anderson model for a single impurity coupled to two leads are studied using the GW approximation. We find that quantities such as the spectral function at zero temperature, the linear-response conductance as function of temperature or the differential conductance as function of bias voltage exhibit universal scaling behavior in the Kondo regime. We show how the form of the GW scaling functions relates to the form of the scaling functions obtained from the exact solution at equilibrium. We also compare the energy scale that goes inside the GW scaling functions with the exact Kondo temperature, for a broad range of the Coulomb interaction strength in the asymptotic regime. This analysis allows to clarify a presently suspended question in the literature, namely whether or not the GW solution captures the Kondo resonance.
FRMAC was born out of circumstances 25 years ago when 17 federal agencies descended on the states with good intention during the Three-Mile Island nuclear power plant incident. At that time it quickly became evident that a better way was needed to support state and local governments in their time of emergency and recovery process. FRMAC's single voice of Federal support coordinates the multiple agencies that respond to a radiological event. Over the years, FRMAC has exercised, evaluated, and honed its ability to quickly respond to the needs of our communities. As the times have changed, FRMAC has expanded its focus from nuclear power plant incidents, to threats of a terrorist radiological dispersal device (RDD), to the unthinkable - an Improvised nuclear device (IND). And just as having the right tools are part of any trade, FRMAC's tool set has and is evolving to meet contemporary challenges - not just to improve the time it takes to collect data and assess the situation, but to provide a quality and comprehensive product that supports a stressed decision maker, responsible for the protection of the public. Innovations in the movement of data and information have changed our everyday lives. So too, FRMAC is capitalizing on industry innovations to improve the flow of information: from the early predictive models, to streamlining the process of getting data out of the field; to improving the time it takes to get assessed products in to the hands of the decision makers. FRMAC is focusing on the future through the digital age of electronic data processing. Public protective action and dose avoidance is the challenge.
In many industrial processes, gaseous moisture is undesirable as it can lead to metal corrosion, polymer degradation, and other materials aging processes. However, generating and measuring precise moisture concentrations is challenging due to the need to cover a broad concentration range (parts-per-billion to percent) and the affinity of moisture to a wide range surfaces and materials. This document will discuss the techniques employed by the Mass Spectrometry Laboratory of the Materials Reliability Department at Sandia National Laboratories to generate and measure known gaseous moisture concentrations. This document highlights the use of a chilled mirror and primary standard humidity generator for the characterization of aluminum oxide moisture sensors. The data presented shows an excellent correlation in frost point measured between the two instruments, and thus provides an accurate and reliable platform for characterizing moisture sensors and performing other moisture related experiments.
The goal of z-pinch inertial fusion energy (IFE) is to extend the single-shot z-pinch inertial confinement fusion (ICF) results on Z to a repetitive-shot z-pinch power plant concept for the economical production of electricity. Z produces up to 1.8 MJ of x-rays at powers as high as 230 TW. Recent target experiments on Z have demonstrated capsule implosion convergence ratios of 14-21 with a double-pinch driven target, and DD neutron yields up to 8x10exp10 with a dynamic hohlraum target. For z-pinch IFE, a power plant concept is discussed that uses high-yield IFE targets (3 GJ) with a low rep-rate per chamber (0.1 Hz). The concept includes a repetitive driver at 0.1 Hz, a Recyclable Transmission Line (RTL) to connect the driver to the target, high-yield targets, and a thick-liquid wall chamber. Recent funding by a U.S. Congressional initiative for $4M for FY04 is supporting research on RTLs, repetitive pulsed power drivers, shock mitigation, full RTL cycle planned experiments, high-yield IFE targets, and z-pinch power plant technologies. Recent results of research in all of these areas are discussed, and a Road Map for Z-Pinch IFE is presented.
This paper discusses implications and appropriate treatment of systematic uncertainty in experiments and modeling. Systematic uncertainty exists when experimental conditions, and/or measurement bias errors, and/or bias contributed by post-processing the data, are constant over the set of experiments but the particular values of the conditions and/or biases are unknown to within some specified uncertainty. Systematic uncertainties in experiments do not automatically show up in the output data, unlike random uncertainty which is revealed when multiple experiments are performed. Therefore, the output data must be properly 'conditioned' to reflect important sources of systematic uncertainty in the experiments. In industrial scale experiments the systematic uncertainty in experimental conditions (especially boundary conditions) is often large enough that the inference error on how the experimental system maps inputs to outputs is often quite substantial. Any such inference error and uncertainty thereof also has implications in model validation and calibration/conditioning; ignoring systematic uncertainty in experiments can lead to 'Type X' error in these procedures. Apart from any considerations of modeling and simulation, reporting of uncertainty associated with experimental results should include the effects of any significant systematic uncertainties in the experiments. This paper describes and illustrates the treatment of multivariate systematic uncertainties of interval and/or probabilistic natures, and combined cases. The paper also outlines a practical and versatile 'real-space' framework and methodology within which experimental and modeling uncertainties (correlated and uncorrelated, systematic and random, aleatory and epistemic) are treated to mitigate risk in model validation, calibration/conditioning, hierarchical modeling, and extrapolative prediction.
The goals of this project are to understand the fundamental principles that govern the formation and function of novel nanoscale and nanocomposite materials. Specific scientific issues being addressed include: design and synthesis of complex molecular precursors with controlled architectures, controlled synthesis of nanoclusters and nanoparticles, development of robust two or three-dimensionally ordered nanocomposite materials with integrated functionalities that can respond to internal or external stimuli through specific molecular interactions or phase transitions, fundamental understanding of molecular self-assembly mechanisms on multiple length scales, and fundamental understanding of transport, electronic, optical, magnetic, catalytic and photocatalytic properties derived from the nanoscale phenomena and unique surface and interfacial chemistry for DOE's energy mission.
With the Lemnos framework, interoperability of control security equipment is straightforward. To obtain interoperability between proprietary security appliance units, one or both vendors must now write cumbersome 'translation code.' If one party changes something, the translation code 'breaks.' The Lemnos project is developing and testing a framework that uses widely available security functions and protocols like IPsec - to form a secure communications channel - and Syslog, to exchange security log messages. Using this model, security appliances from two or more different vendors can clearly and securely exchange information, helping to better protect the total system. Simplify regulatory compliance in a complicated security environment by leveraging the Lemnos framework. As an electric utility, are you struggling to implement the NERC CIP standards and other regulations? Are you weighing the misery of multiple management interfaces against committing to a ubiquitous single-vendor solution? When vendors build their security appliances to interoperate using the Lemnos framework, it becomes practical to match best-of-breed offerings from an assortment of vendors to your specific control systems needs. The Lemnos project is developing and testing a framework that uses widely available open-source security functions and protocols like IPsec and Syslog to create a secure communications channel between appliances in order to exchange security data.
The internal structure of stars depends on the radiative opacity of the stellar matter. However, opacity models have never been experimentally tested at the conditions that exist inside stars. Experiments at the Sandia Z facility are underway to measure the x-ray transmission of iron, an important stellar constituent, at temperature and density high enough to evaluate the physical underpinnings of stellar opacity models. Initial experiments provided information on the charge state distribution and the energy level structure for the iron ions that exist at the solar radiation/convection boundary. Data analysis and new experiments at higher densities and temperatures will be described.
Changing paradigms from paper laboratory notebooks to electronic creates challenges. Meeting regulatory requirements in an R&D environment drives thorough documentation. Creating complete experimental records is easier using electronic laboratory notebooks. Supporting investigations through re-creating experimental conditions is greatly facilitated using an ELN.
Pandemic influenza has become a serious global health concern; in response, governments around the world have allocated increasing funds to containment of public health threats from this disease. Pandemic influenza is also recognized to have serious economic implications, causing illness and absence that reduces worker productivity and economic output and, through mortality, robs nations of their most valuable assets - human resources. This paper reports two studies that investigate both the short- and long-term economic implications of a pandemic flu outbreak. Policy makers can use the growing number of economic impact estimates to decide how much to spend to combat the pandemic influenza outbreaks. Experts recognize that pandemic influenza has serious global economic implications. The illness causes absenteeism, reduced worker productivity, and therefore reduced economic output. This, combined with the associated mortality rate, robs nations of valuable human resources. Policy makers can use economic impact estimates to decide how much to spend to combat the pandemic influenza outbreaks. In this paper economists examine two studies which investigate both the short- and long-term economic implications of a pandemic influenza outbreak. Resulting policy implications are also discussed. The research uses the Regional Economic Modeling, Inc. (REMI) Policy Insight + Model. This model provides a dynamic, regional, North America Industrial Classification System (NAICS) industry-structured framework for forecasting. It is supported by a population dynamics model that is well-adapted to investigating macro-economic implications of pandemic influenza, including possible demand side effects. The studies reported in this paper exercise all of these capabilities.
This document provides common best practices for the efficient utilization of parallel file systems for analysts and application developers. A multi-program, parallel supercomputer is able to provide effective compute power by aggregating a host of lower-power processors using a network. The idea, in general, is that one either constructs the application to distribute parts to the different nodes and processors available and then collects the result (a parallel application), or one launches a large number of small jobs, each doing similar work on different subsets (a campaign). The I/O system on these machines is usually implemented as a tightly-coupled, parallel application itself. It is providing the concept of a 'file' to the host applications. The 'file' is an addressable store of bytes and that address space is global in nature. In essence, it is providing a global address space. Beyond the simple reality that the I/O system is normally composed of a small, less capable, collection of hardware, that concept of a global address space will cause problems if not very carefully utilized. How much of a problem and the ways in which those problems manifest will be different, but that it is problem prone has been well established. Worse, the file system is a shared resource on the machine - a system service. What an application does when it uses the file system impacts all users. It is not the case that some portion of the available resource is reserved. Instead, the I/O system responds to requests by scheduling and queuing based on instantaneous demand. Using the system well contributes to the overall throughput on the machine. From a solely self-centered perspective, using it well reduces the time that the application or campaign is subject to impact by others. The developer's goal should be to accomplish I/O in a way that minimizes interaction with the I/O system, maximizes the amount of data moved per call, and provides the I/O system the most information about the I/O transfer per request.
Despite decades of international consensus that deep geological disposal is the best option for permanent management of long-lived high-level radioactive wastes, no repositories for used nuclear fuel or high-level waste are in operation. Detailed long-term safety assessments have been completed worldwide for a wide range of repository designs and disposal concepts, however, and valuable insights from these assessments are available to inform future decisions about managing radioactive wastes. Qualitative comparisons among the existing safety assessments for disposal concepts in clay, granite, salt, and unsaturated volcanic tuff show how different geologic settings can be matched with appropriate engineered barrier systems to provide a high degree of confidence in the long-term safety of geologic disposal. Review of individual assessments provides insights regarding the release pathways and radionuclides that are most likely to contribute to estimated doses to humans in the far future for different disposal concepts, and can help focus research and development programs to improve management and disposal technologies. Lessons learned from existing safety assessments may be particularly relevant for informing decisions during the process of selecting potential repository sites.
This document provides detailed test results of ballistic impact experiments performed on several types of high performance concrete. These tests were performed at the Sandia National Laboratories Shock Thermodynamic Applied Research Facility using a 50 caliber powder gun to study penetration resistance of concrete samples. This document provides test results for ballistic impact experiments performed on two types of concrete samples, (1) Ductal{reg_sign} concrete is a fiber reinforced high performance concrete patented by Lafarge Group and (2) ultra-high performance concrete (UHPC) produced in-house by DoD. These tests were performed as part of a research demonstration project overseen by USACE and ERDC, at the Sandia National Laboratories Shock Thermodynamic Applied Research (STAR) facility. Ballistic penetration tests were performed on a single stage research powder gun of 50 caliber bore using a full metal jacket M33 ball projectile with a nominal velocity of 914 m/s (3000 ft/s). Testing was observed by Beverly DiPaolo from ERDC-GSL. In all, 31 tests were performed to achieve the test objectives which were: (1) recovery of concrete test specimens for post mortem analysis and characterization at outside labs, (2) measurement of projectile impact velocity and post-penetration residual velocity from electronic and radiographic techniques and, (3) high-speed photography of the projectile prior to impact, impact and exit of the rear surface of the concrete construct, and (4) summarize the results.
Climate change is a long-term process that will trigger a range of multi-dimensional demographic, economic, geopolitical, and national security issues with many unknowns and significant uncertainties. At first glance, climate-change-related national security dimensions seem far removed from today's major national security threats. Yet climate change has already set in motion forces that will require U.S. attention and preparedness. The extent and uncertainty associated with these situations necessitate a move away from conventional security practices, toward a small but flexible portfolio of assets to maintain U.S. interests. Thoughtful action is required now if we are to acquire the capabilities, tools, systems, and institutions needed to meet U.S. national security requirements as they evolve with the emerging stresses and shifts of climate change.
Herranz, T.; McCarty, K.F.; Santos, B.; Monti, M.; De La Figuera, J.
The growth and decomposition of thin layers of Mg and magnesium hydride on Ru(0001) using an in situ technique that provides real-space, real-time observations of the formation of hydride islands, was reported. The experiments have been performed using low energy electron microscopy (LEEM). Using LEEM, the growth of films was followed up to 10 atomic layers (AL) for temperatures between 300 and 430 K. With increased exposure time, there is little further nucleation. The LEED patterns of the 4 AL Mg film shows two sets of 6-fold diffraction spots, one set from the film and the other from the substrate. After being exposed to hydrogen the films were heated in UHV and the surface was simultaneously imaged by LEEM and gas generation monitored by temperature desorption (TD). In the LEEM images, no changes were observed up to temperatures around 450 K. From this temperature desorption of the Mg layers started. An increase in the decomposition temperature is observed with thicker original Mg films.
Rates of reactions can be expressed as dn/dt = kcf(n) where n is moles of reaction, k is a rate constant, c is a proportionality constant, and f(n) is a function of the properties of the sample. When the instrument time constant, ?, and k are sufficiently comparable that measured rates are significantly affected by instrument response, correction for instrument response must be done to obtain accurate reaction kinetics. Correction for instrument response has previously been done by truncating early data or by use of the Tian equation. Both methods can lead to significant errors. We describe a method for simultaneous determination of ?, k, and c by fitting equations describing the combined instrument response and rate law to rates observed as a function of time. The method was tested with data on the heat rate from acid-catalyzed hydrolysis of sucrose.
Near-field scanning microwave microscopy is employed for quantitative imaging at 4 GHz of the local impedance for monolayer and few-layer graphene. The microwave response of graphene is found to be thickness dependent and determined by the local sheet resistance of the graphene flake. Calibration of the measurement system and knowledge of the probe geometry allows evaluation of the AC impedance for monolayer and few-layer graphene, which is found to be predominantly active. The use of localized evanescent electromagnetic field in our experiment provides a promising tool for investigations of plasma waves in graphene with wave numbers determined by the spatial spectrum of the near-field. By using near-field microwave microscopy one can perform simultaneous imaging of location, geometry, thickness, and distribution of electrical properties of graphene without a need for device fabrication.
Portable remote sensing devices are increasingly needed to cost effectively characterize the meteorology at a potential wind energy site as the size of modern wind turbines increase. A short term project co-locating a Sound Detection and Ranging System (SODAR) with a 200 meter instrumented meteorological tower at the Texas Tech Wind Technology Field Site was performed to collect and summarize wind information through an atmospheric layer typical of utility scale rotor plane depths. Data collected identified large speed shears and directional shears that may lead to unbalanced loads on the rotors. This report identifies suggestions for incorporation of additional data in wind resource assessments and a few thoughts on the potential for using a SODAR or SODAR data to quantify or investigate other parameters that may be significant to the wind industry.
This assessment takes the result of the FY08 performance target baseline of mercury at Sandia National Laboratories/New Mexico, and records the steps taken in FY09 to collect additional data, encourage the voluntary reduction of mercury, and measure success. Elemental (metallic) mercury and all of its compounds are toxic, and exposure to excessive levels can permanently damage or fatally injure the brain and kidneys. Elemental mercury can also be absorbed through the skin and cause allergic reactions. Ingestion of inorganic mercury compounds can cause severe renal and gastrointestinal damage. Organic compounds of mercury such as methyl mercury, created when elemental mercury enters the environment, are considered the most toxic forms of the element. Exposures to very small amounts of these compounds can result in devastating neurological damage and death.1 SNL/NM is required to report annually on the site wide inventory of mercury for the Environmental Protection Agency's (EPA) Toxics Release Inventory (TRI) Program, as the site's inventory is excess of the ten pound reportable threshold quantity. In the fiscal year 2008 (FY08) Pollution Prevention Program Plan, Section 5.3 Reduction of Environmental Releases, a performance target stated was to establish a baseline of mercury, its principle uses, and annual quantity or inventory. This was accomplished on July 29, 2008 by recording the current status of mercury in the Chemical Information System (CIS).
Knight & Carver was contracted by Sandia National Laboratories to develop a Sweep Twist Adaptive Rotor (STAR) blade that reduced operating loads, thereby allowing a larger, more productive rotor. The blade design used outer blade sweep to create twist coupling without angled fiber. Knight & Carver successfully designed, fabricated, tested and evaluated STAR prototype blades. Through laboratory and field tests, Knight & Carver showed the STAR blade met the engineering design criteria and economic goals for the program. A STAR prototype was successfully tested in Tehachapi during 2008 and a large data set was collected to support engineering and commercial development of the technology. This report documents the methodology used to develop the STAR blade design and reviews the approach used for laboratory and field testing. The effort demonstrated that STAR technology can provide significantly greater energy capture without higher operating loads on the turbine.
A Sewer System Management Plan (SSMP) is required by the State Water Resources Control Board (SWRCB) Order No. 2006-0003-DWQ Statewide General Waste Discharge Requirements (WDR) for Sanitary Sewer Systems (General Permit). DOE, National Nuclear Security Administration (NNSA), Sandia Site Office has filed a Notice of Intent to be covered under this General Permit. The General Permit requires a proactive approach to reduce the number and frequency of sanitary sewer overflows (SSOs) within the State. SSMPs must include provisions to provide proper and efficient management, operation, and maintenance of sanitary sewer systems and must contain a spill response plan. Elements of this Plan are under development in accordance with the SWRCB's schedule.
The intent of this study is to provide an analysis of the scattering from a crevasse in Antarctic ice, utilizing a physics-based model for the scattering process. Of primary interest is a crevasse covered with a snow bridge, which makes the crevasse undetectable in visible-light images. It is demonstrated that a crevasse covered with a snow bridge can be visible in synthetic-aperture-radar (SAR) images. The model of the crevasse and snow bridge incorporates a complex dielectric permittivity model for dry snow and ice that takes into account the density profile of the glacier. The surface structure is based on a fractal model that can produce sastrugi-like features found on the surface of Antarctic glaciers. Simulated phase histories, computed with the Shooting and Bouncing Ray (SBR) method, are processed into SAR images. The viability of the SBR method for predicting scattering from a crevasse covered with a snow bridge is demonstrated. Some suggestions for improving the model are given.
Sandia National Laboratories is currently developing new processing and data communication architectures for use in future satellite payloads. These architectures will leverage the flexibility and performance of state-of-the-art static-random-access-memory-based Field Programmable Gate Arrays (FPGAs). One such FPGA is the radiation-hardened version of the Virtex-5 being developed by Xilinx. However, not all features of this FPGA are being radiation-hardened by design and could still be susceptible to on-orbit upsets. One such feature is the embedded hard-core PPC440 processor. Since this processor is implemented in the FPGA as a hard-core, traditional mitigation approaches such as Triple Modular Redundancy (TMR) are not available to improve the processor's on-orbit reliability. The goal of this work is to investigate techniques that can help mitigate the embedded hard-core PPC440 processor within the Virtex-5 FPGA other than TMR. Implementing various mitigation schemes reliably within the PPC440 offers a powerful reconfigurable computing resource to these node-based processing architectures. This document summarizes the work done on the cache mitigation scheme for the embedded hard-core PPC440 processor within the Virtex-5 FPGAs, and describes in detail the design of the cache mitigation scheme and the testing conducted at the radiation effects facility on the Texas A&M campus.
An increasing number of corporate security policies make it desirable to push security closer to the desktop. It is not practical or feasible to place security and monitoring software on all computing devices (e.g. printers, personal digital assistants, copy machines, legacy hardware). We have begun to prototype a hardware and software architecture that will enforce security policies by pushing security functions closer to the end user, whether in the office or home, without interfering with users' desktop environments. We are developing a specialized programmable Ethernet network switch to achieve this. Embodied in this device is the ability to detect and mitigate network attacks that would otherwise disable or compromise the end user's computing nodes. We call this device a 'Secure Programmable Switch' (SPS). The SPS is designed with the ability to be securely reprogrammed in real time to counter rapidly evolving threats such as fast moving worms, etc. This ability to remotely update the functionality of the SPS protection device is cryptographically protected from subversion. With this concept, the user cannot turn off or fail to update virus scanning and personal firewall filtering in the SPS device as he/she could if implemented on the end host. The SPS concept also provides protection to simple/dumb devices such as printers, scanners, legacy hardware, etc. This report also describes the development of a cryptographically protected processor and its internal architecture in which the SPS device is implemented. This processor executes code correctly even if an adversary holds the processor. The processor guarantees both the integrity and the confidentiality of the code: the adversary cannot determine the sequence of instructions, nor can the adversary change the instruction sequence in a goal-oriented way.
We recently performed an evaluation of the implications of a reduced stockpile of nuclear weapons for surveillance to support estimates of reliability. We found that one technique developed at Sandia National Laboratories (SNL) under-estimates the required sample size for systems-level testing. For a large population the discrepancy is not important, but for a small population it is important. We found that another technique used by SNL provides the correct required sample size. For systems-level testing of nuclear weapons, samples are selected without replacement, and the hypergeometric probability distribution applies. Both of the SNL techniques focus on samples without defects from sampling without replacement. We generalized the second SNL technique to cases with defects in the sample. We created a computer program in Mathematica to automate the calculation of confidence for reliability. We also evaluated sampling with replacement where the binomial probability distribution applies.
This paper describes a new hybrid modeling and simulation architecture developed at Sandia for understanding and developing protections against and mitigations for cyber threats upon control systems. It first outlines the challenges to PCS security that can be addressed using these technologies. The paper then describes Virtual Control System Environments (VCSE) that use this approach and briefly discusses security research that Sandia has performed using VCSE. It closes with recommendations to the control systems security community for applying this valuable technology.
