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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,549 records · Page 86
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Multiple operating system rotation environment moving target defense

Systems and methods for providing a multiple operating system rotation environment ("MORE") moving target defense ("MTD") computing system are described. The MORE-MTD system provides enhanced computer system security through a rotation of multiple operating systems. The MORE-MTD system increases attacker uncertainty, increases the cost of attacking the system, reduces the likelihood of an attacker locating a vulnerability, and reduces the exposure time of any located vulnerability. The MORE-MTD environment is effectuated by rotation of the operating systems at a given interval. The rotating operating systems create a consistently changing attack surface for remote attackers.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2016

Multiple objective optimization in reliability demonstration test

Reliability demonstration tests are usually performed in product design or validation processes to demonstrate whether a product meets specified requirements on reliability. For binomial demonstration tests, the zero-failure test has been most commonly used due to its simplicity and use of minimum sample size to achieve an acceptable consumer’s risk level. However, this test can often result in unacceptably high risk for producers as well as a low probability of passing the test even when the product has good reliability. This paper explicitly explores the interrelationship between multiple objectives that are commonly of interest when planning a demonstration test and proposes structured decision-making procedures using a Pareto front approach for selecting an optimal test plan based on simultaneously balancing multiple criteria. Different strategies are suggested for scenarios with different user priorities and graphical tools are developed to help quantify the trade-offs between choices and to facilitate informed decision making. As a result, potential impacts of some subjective user inputs on the final decision are studied to offer insights and useful guidance for general applications.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2016

Optic probe for multiple angle image capture and optional stereo imaging

A probe including a multiple lens array is disclosed to measure velocity distribution of a moving surface along many lines of sight. Laser light, directed to the moving surface is reflected back from the surface and is Doppler shifted, collected into the array, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to the multiple lens array. Numerous fibers in a fiber array project numerous rays to establish many measurement points at numerous different locations. One or more lens groups may be replaced with imaging lenses so a stereo image of the moving surface can be recorded. Imaging a portion of the surface during initial travel can determine whether the surface is breaking up.

42 ENGINEERING↗
DOE OSTI2017

Measurement of Reconstructed Charged Particle Multiplicities of Neutrino Interactions in MicroBooNE

Here, we compare the observed charged particle multiplicity distributions in the MicroBooNE liquid argon time projection chamber from neutrino interactions in a restricted final state phase space to predictions of this distribution from several GENIE models. The measurement uses a data sample consisting of neutrino interactions with a final state muon candidate fully contained within the MicroBooNE detector. These data were collected in 2015-2016 with the Fermilab Booster Neutrino Beam (BNB), which has an average neutrino energy of 800 MeV, using an exposure corresponding to 5e19 protons-on-target. The analysis employs fully automatic event selection and charged particle track reconstruction and uses a data-driven technique to determine the contribution to each multiplicity bin from neutrino interactions and cosmic-induced backgrounds. The restricted phase space employed makes the measurement most sensitive to the higher-energy charged particles expected from primary neutrino-argon collisions and less sensitive to lower energy protons expected to be produced in final state interactions of collision products with the target argon nucleus.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2018

Redox flow batteries having multiple electroactive elements

Introducing multiple redox reactions with a suitable voltage range can improve the energy density of redox flow battery (RFB) systems. One example includes RFB systems utilizing multiple redox pairs in the positive half cell, the negative half cell, or in both. Such RFB systems can have a negative electrolyte, a positive electrolyte, and a membrane between the negative electrolyte and the positive electrolyte, in which at least two electrochemically active elements exist in the negative electrolyte, the positive electrolyte, or both.

25 ENERGY STORAGE↗
DOE OSTI2016

Efficient assembly of multiple pane windows

This invention describes a process flow and method to assemble triple IG units without contaminating the center glass lite. A non-contact vacuum pad is used to lift a glass lite off from a horizontal or vertical support that conveys it from a glass washer to an assembly station. Each of multiple pads has a capacity to lift approximately seven to ten pounds. Use of multiple pads per glass sheet or lite allows lites having dimensions up to 70 by 100 inches (assuming glass thickness of one quarter inch) to be assembled.

Briese, William↗
DOE OSTI2019

Multiple band gap Co-Ni oxide compositions and applications thereof

In one aspect, metal oxide compositions having electronic structure of multiple band gaps are described. In some embodiments, a metal oxide composition comprises a (Co,Ni)O alloy having electronic structure including multiple band gaps. The (Co,Ni)O alloy can include a first band gap and a second band gap, the first band gap separating valence and conduction bands of the electronic structure.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Neutron multiplicity detector control circuitry and firmware

Neutron multiplicity detector control logic and firmware may control a neutron multiplicity detector such that higher count rates can be achieved by an order of magnitude of more over conventional control logic and firmware. Count rates of over 1,000,000 cps, and even over 1,500,000 cps, have been realized in some implementations.

Nelson, Mark↗
DOE OSTI2017

Measuring the Higgsplosion Yield: Counting Large Higgs Multiplicities at Colliders

Recent work has brought renewed attention to the possibility that the cross section for producing n Higgs bosons grows large with n at a sufficiently energetic hadron collider. In particular, this "Higgsplosion'" mechanism has been suggested as a solution to the hierarchy problem. In this work, we investigate the phenomenology of this scenario. Discovery is trivial, so we consider several variables for use in measuring large Higgs multiplicities and evaluate their effectiveness. We find that a 10% level measurement of the number of Higgs bosons is possible with a handful of events, using the scalar sum of jet transverse momenta, but determining the exact multiplicity may take a few thousand events, depending on the degree of statistical significance desired for the measurement. While this situation may be acceptable given the potentially large cross sections in this scenario, future research to improve the measurement is warranted.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

Enhanced Dynamic Equivalent Identification Method of Large-Scale Power Systems Using Multiple Event

The increasing complexity of the interconnected power system makes high-fidelity dynamic simulation models computationally more intensive. To improve computation efficiency, model reduction techniques have been investigated to only preserve the dynamics in a limited area of interest (study area), while deriving equivalent representation for the external area. For this purpose, a measurement-based reduction approach using system identification techniques has been previously proposed. In that case, external areas are represented by dynamic equivalent loads using transfer function estimation. In this paper, in order to enhance the accuracy of the reduced model in preserving dynamics of the study area, multiple “grid” events of different types and at different locations are considered for identifying the parameters of the equivalent loads. Case studies are carried out in the NPCC 140-bus system. Comparison are made between multiple events training and single event training, highlighting the advantages of the proposed method in providing a better representation of the grid dynamics under different operating conditions.

Xue, Yaosuo↗
DOE OSTI2020

Decorrelating effects in multiple linear regression to decompose and attribute risk to common and proper effects

Effects in multiple linear regression may be decorrelated to decompose and attribute risk to common and proper effects. In other words, an attribute risk may be decomposed to two or more causes, where each cause is characterized by multiple attributes. The risk decomposition may decompose risk into a first residual part associated with a first set of risk factors, a second residual part associated with a second set of risk factors, and a common part associated with a set of common hidden variables that minimize a correlation between the first set of factors and the second set of factors. The common hidden variables may be modeled using a hidden factor model. An effect of the correlation may be minimized on the first set of risk factors and the second set of risk factors, and how correlated the terms of the risk decomposition are may be quantified.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2022

Graph-Augmented Normalizing Flows for Anomaly Detection of Multiple Time Series

Anomaly detection is a widely studied task for a broad variety of data types; among them, multiple time series appear frequently in applications, including for example, power grids and traffic networks. Detecting anomalies for multiple time series, however, is a challenging subject, owing to the intricate interdependencies among the constituent series. We hypothesize that anomalies occur in low density regions of a distribution and explore the use of normalizing flows for unsupervised anomaly detection, because of their superior quality in density estimation. Moreover, we propose a novel flow model by imposing a Bayesian network among constituent series. A Bayesian network is a directed acyclic graph (DAG) that models causal relationships; it factorizes the joint probability of the series into the product of easy-to-evaluate conditional probabilities. We call such a graph-augmented normalizing flow approach GANF and propose joint estimation of the DAG with flow parameters. We conduct extensive experiments on real-world datasets and demonstrate the effectiveness of GANF for density estimation, anomaly detection, and identification of time series distribution drift.

Dai, Enyan↗
DOE OSTI2021

Examination of New Theory for Neutron Multiplicity Counting of Non-Point-Like Sources of Special Nuclear Material

The purpose of a nondestructive assay is to accurately verify the declared mass of special nuclear material (SNM) samples in a limited amount of time. One measurement modality is neutron multiplicity counting (NMC), which relates time-correlated neutron detection rates to the mass of SNM present. Traditional theory assumes point-like sources, which can be ill-posed for kilogram-quantity, bulk samples. Recent theory was developed to improve NMC accuracy for non-point-like samples. This work preliminarily examines the theory with measured data. The OSCAR prototype (a 3-by-4 array of 5.08-cm-thick, 5.08-cm-diameter trans-stilbene organic scintillators) measures configurations of 29.41-49.00 kg of highly enriched uranium (93wt% 235 U). Adjusted factorial moments for the emitted neutron multiplicity distributions are used to account for the shape and type of SNM being measured.

252Cf↗
DOE OSTI2022

239 Pu R -matrix Analysis and Neutron Multiplicities in the Neutron Energy Region up to a few keVs [Abstract]

The evaluation of 239 Pu neutron resonance parameters coupled to neutron multiplicities $\overline{v}_p$ is of particular importance to investigate the ($\mathcal{n, γf}$) reaction in which a $\mathcal{γ}$-ray emission occurs before the scission of the compound nuclear. This reaction has offered one explanation for the fluctuations in the measured values of $\overline{v}_p$ In this regard, the competition between ($\mathcal{n, γf}$) reaction and the direct fission process can be also included in the R matrix analysis of fission and capture measured data. The goal of this work is the coupled evaluation of the $\mathcal{n}$+ 239 Pu resonance parameters and related neutron multiplicities by ensuring the adoption of thermal neutron constants recently evaluated at the International Atomic Nuclear Energy as well as the recommended (thermal-neutron) induced prompt neutron fission spectrum (PFNS). Moreover, this new set of physical evaluated quantities should also guarantee the agreement for high-leakage solution benchmarks while keeping the good performance of large thermal solution assemblies.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2013

Comparison of REMIX vs. MOX fuel characteristics in multiple recycling in VVER reactor

Multiple recycling of regenerated uranium-plutonium fuel in thermal reactors of VVER-1000 type with high enriched uranium feeding (REMIX-fuel) gives a possibility to terminate the accumulation of spent nuclear fuels (SNF) and Pu and decrease the accumulation of irradiated uranium by an order of magnitude. Results of comparison of VVER-1000 nuclear fuel cycle characteristics vs different fuel types such as UOX, MOX and REMIX-fuel have been presented. REMIX fuel (Regenerated Mixture of U-, Pu oxides) is the mixture of plutonium and uranium extracted from SNF and refined from other actinides and fission products with the addition of enriched uranium to provide the power potential necessary. The savings in terms of uranium quantities and separation works in the nuclear energy system (NES) with reactors using REMIX-fuel compared to the NES with uranium-fuelled reactors are shown to be of about 30% and 8%, respectively. For the NES with thermal reactors partially loaded with MOX-fuel, the uranium and separation works saving of about 14% would be obtained. Production of neptunium and americium in reactors with REMIX-fuel in steady state increases by a factor 3, and production of curium - by 10 compared to the reactors with UOX-fuel. This increase of minor actinide buildup is owed to the multiple recycling of plutonium. It should be noted that in this case all fuel assemblies contain high-background plutonium, and their manufacturing involves an expensive technology. Besides, management of REMIX-fuel will require special protection measures even during the fresh fuel manufacturing phase. The above-said gives ground to state that the use of REMIX fuel would be questionable in economic aspect.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2016

Use of Multiple Remote Systems for Calcine Retrieval Operations at Idaho - 16592

There are approximately 5000 m{sup 3} of radioactive calcine material stored in six Calcine Solids Storage Facilities (CSSFs) at the DOE Idaho site. Each CSSF contains from three to twelve stainless steel tanks surrounded by a concrete vault. In accordance with the Idaho Settlement Agreement (ISA), this waste has to be retrieved and immobilized by December 31 2035 although no final decision has yet been made on how the calcine wastes are going to be retrieved from the CSSF's. One of the primary issues with the retrieval is that, in accordance with the ISA, any existing risers into the tanks have to be used 'to the maximum extent possible' in the retrieval process. Since these risers are only 6-8'' in diameter, this limits the types of systems that can be used for the retrieval. In addition, each bin containing the calcine has a series of obstructions which need to be navigated around and so inflexible systems such as conventional hose-based vacuum type systems are not feasible. In addition, the retrieval system selected has to be able to manage multiple forms of calcine (powder, granular, agglomerated, chunks etc) and operate in a very highly radioactive environment. This paper describes the progress made to date in developing an approach based on the use of multiple remote system platforms to gain entry into the bin-sets and to safely and cost-effectively retrieve the calcine wastes. Much of the work has focused on the application of the OC Robotic snake-arm robot system although significant effort has also been allocated to understanding the deployment mechanism of the snake-arm and to the ancillary supporting systems such as those for contamination control, cutting and welding new risers into the bin-sets and vacuum hose management within the bin-set. Future work will include the construction of a scaled mock up to demonstrate the field implementation of the system. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

A Multiple Lines of Evidence Approach for Conceptual Site Models in Performance Assessments - 19070

Demonstration of the long-term performance of remediated radioactive waste sites relies on models that evaluate vadose zone and groundwater flow and contaminant transport for thousands of years. Model qualification, verification, and comparisons with data are essential elements to demonstrating the accuracy of long-term performance assessments (PAs). However, comparisons with data are generally limited due to incomplete characterization data and long-time scales. Since PAs support decision making to assure long-term protection of both human health and the environment, a conceptual site model (CSM) is needed to explain the hydrodynamic behavior and account for subsurface heterogeneities in sufficient detail to support confident decisions. In the case of the Waste Management Area (WMA) C PA, where the focus of the effort is on characterizing flow and transport through a thick vadose zone, site-specific data are sparse and larger-scale geologic descriptions are adopted with the risk of losing small scale features that may affect contaminant transport. Features such as horizontal bedding and sloping interfaces between contrasting material types, as well as vertically oriented features such as clastic dikes, may be difficult to delineate from sparse characterization data, but may affect the extent to which contaminants are transported. The PA conducted to identify long-term impacts associated with the closure of the single-shell tank (SST) farm at WMA C adopted an equivalent homogenous medium approach to represent the major stratigraphic units at the site. This approach explicitly represents major stratigraphic units but assigns hydraulic properties that implicitly account for the presence of small-scale heterogeneities and their impact on flow and contaminant transport to the groundwater. The objective of this study is to evaluate the available site-specific and analogue data that can be used to characterize heterogeneity and to assess its impact on fate and transport of contaminants that may lead to different conclusions when compared to the results of the equivalent homogeneous media approach. To this end, a multiple lines of evidence approach was used to construct alternative CSMs based on an evaluation of several types of data. These data include 1) general characteristics and features of the major stratigraphic units from historical descriptions; 2) borehole geologic logs; 3) particle size distribution measurements; 4) moisture content measurements; 5) spectral gamma data; and 6) concentrations of key constituents (i.e., Tc-99) in both the vadose zone and groundwater impacted by past releases. Based on an analysis of the available data, lines of evidence are evaluated for consistency and integrated in a consistent manner into scientifically defensible CSMs. Numerical models are then used to evaluate the impact that the explicit representation of heterogeneities has on contaminant transport. Together, the field data and the numerical modeling results indicate that heterogeneity caused by the small-scale features do not have a significant (i.e. greater than a factor of 2) impact on transport below WMA C relative to peak concentrations and arrival times for potential releases from waste tanks. The results of this study underscore the value of using multiple lines of evidence based on the quantity and quality of available data in developing alternative CSMs and evaluating their relative impact on key transport metrics such as arrival times and peak concentration. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Evaluating Environmental Remediation Performance at Radwaste Sites Using Multiple, Censored Regression Analysis - 19348

Located on the U.S. Department of Energy's Hanford Site in Richland,Washington, the 300 Area's remediation performance monitoring requires assessment of concentration trends and calculation of means and lower and upper confidence limits on the mean. The performance monitoring wells for uranium are located within 400 m of the Columbia River and groundwater elevations and uranium concentrations are influenced by groundwater-surface water interactions. A multiple regression approach was used to assess trends because multiple covariates can be used to account for the observed fluctuations in groundwater elevation and concentration. Incorporation of covariates accounting for these groundwater-surface water interactions (i.e., river stage) reduces the random error in the trend estimation and improves the estimates of remediation performance metrics (i.e., mean and confidence limits on the mean) over traditional, non-parametric methods. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗