Pulse models of human operators performing compensatory tracking with coordinated multiple inputs
Human performance and eye movements of operator performing compensatory tracking with coordinated multiple inputs
COMPENSATORY TRACKING↗
SEARCH · Engineering Papers
Results for “Input”
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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REopt Lite Tutorial: Load Profile Inputs
This tutorial gives an overview of the load profile inputs in the REopt Lite™ web tool.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
REopt Lite Tutorial: Advanced Utility Rate Inputs
This tutorial gives an overview of the advanced utility rate inputs in the REopt Lite™ web tool.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
REopt Lite Tutorial: Load Profile Inputs
This tutorial gives an overview of the load profile inputs in the REopt Lite™ web tool.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
REopt Lite Tutorial: Advanced Utility Rate Inputs
This tutorial gives an overview of the advanced utility rate inputs in the REopt Lite™ web tool.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Radiation Detection System Integration Using Multiple-Input Multiple-Output Radios
This study describes the application development of multiple-input multiple-output radios to provide persistent mobile ad hoc network (MANET) for the Department of Homeland Security. By using Man Portable Unit (MPU5) fifth generation radios (manufactured by Persistent Systems) with the Android Team Awareness Kit (ATAK), an Android smartphone geospatial infrastructure and military situational awareness application, the Remote Sensing Laboratory has developed a MANET connectivity to monitor deployed nuclear/radiological search operation assets.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Measuring Economy-Wide Circularity of the United States: An Input-Output Model in Mass Units
The ideal of creating closed material cycles by transforming the way we make, use and repurpose goods has become known as the circular economy. Besides its visionary appeal, material efficiency strategies central to circular economy can allow us to meet decarbonization goals that are otherwise out of reach. Production of basic materials such as cement, iron and steel and petrochemicals is one of the largest drivers of greenhouse gas emissions. Measuring circularity, and understanding its relationship with other sustainability metrics, however, is still difficult due to lack of data in mass units covering the entire economic system. Input-output (I-O) tables were originally created as a means of tracking the monetary flows that represent exchanges of goods and services within an economy, but have found additional uses in life cycle assessment and material flow accounts. In the traditional approach of environmentally extended I-O tables, emissions and energy data augment monetary flows. This approach can lead to price effects that distort physical quantities. Also, circular economy strategies and their goals relate to mass, not monetary flows. Therefore, it is best to simulate them using physical quantities. With these issues in mind, we have developed I-O tables in mass units to measure the flow of goods in the U.S. economy. This allows us to better measure how circular the economy really is, and how policy changes to affect this circularity may also affect decarbonization goals. Improving knowledge of these linkages could allow manufacturers to make changes in their production to achieve their sustainability and decarbonization targets. Our tool also provides a standard approach and public repository for data in physical units, making such data more available, useful, and meaningful. Following an established set of material flow metrics used by the European Union, we have used our tool to calculate material footprints over time differentiated by oil and gas versus other extractive industries. This approach also shows the relative trade balances of the U.S. in materials. We have developed a case study for the iron and steel sector, showing how different decarbonization scenarios affect not only economy-wide greenhouse gas emissions, but also total material use.
circular economy↗
High Resolution Measurements Reveal Transient Boiling Phenomena under Exponential Heat Inputs
Transient boiling heat transfer is important to the safety of nuclear reactors. Reactivity insertion accidents (RIA) in a nuclear reactor might result in a power excursion in which the heat generation in the fuel rises exponentially with time. The period of the exponential power excursion depends upon the magnitude of the reactivity insertion. The heat generated within the fuel is transferred to the water coolant which then starts to boil. The reactivity feedbacks caused by the heating (Doppler in the fuel and void in the coolant) represent an important mitigation mechanism for such accidents. The time delay between heat generation in the fuel and its transfer to the coolant is key to determining the outcome of the accident, in particular for experimental reactors using highly enriched fissile fuel with a very low Doppler effect. This time delay depends on conduction heat transfer within the fuel, single-phase convective heat transfer and eventually transient boiling heat transfer in the coolant. Although existing transient boiling databases form a highly valuable source of information, sometimes conclusions from different authors are quantitatively and qualitatively in disagreement with each other. This is likely due to differences in experimental setups and also limitations in the accuracy of diagnostics available in those experiments. In order to clarify these discrepancies and shed light on the mechanisms of transient boiling heat transfer, a new experimental study of both pool and flow boiling under exponential power input were carried out respectively. Exponential power escalation periods from 5 ms to 100 ms, bulk temperatures from saturation to 75 K of subcooling and Reynolds number from 25000 to 60000 have been explored at ambient pressure in both pool and flow boiling conditions. What makes this study unique is the use of synchronized state-of-the-art diagnostics such as IR thermometry and high speed video (HSV) which has improved the accuracy of measured quantities, and has provided a new and unique insights into the transient boiling heat transfer, including detection and modeling of the onset of nucleate boiling, better understanding of the transient boiling process and revelation of a new heat transfer mechanism that leads to higher CHF. (authors)
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
An ensemble of ocean reanalyses for 1815-2013 with sparse observational input
This paper describes a new eight-member ensemble of ocean reanalyses spanning nearly 200 years from 1815 to 2013 generated using the Simple Ocean Data Assimilation system with sparse observational input (SODAsi) to explore long-term changes in the oceans. The eight ensemble members assimilate surface temperature observations and use surface boundary conditions from an atmospheric reanalysis that is loosely coupled to the ocean reanalysis. In this work, both surface and subsurface quantities, such as dynamic height and heat content, show a broad spectrum of variability. Surface temperature trends from 1815 to 2013 are positive in most regions, with some important exceptions; the central Tropical Pacific, around Antarctica, and in the Gulf Stream and Kuroshio extension regions all show cooling trends. A near-global average shows warming of about 0.8°C over the full period, with most of the warming occurring after 1920. There is pronounced multidecadal variability in both the midlatitude and tropical oceans. In the North Atlantic Ocean, temperature variability is highly correlated with the meridional overturning stream function, with the largest correlation occurring when the stream function is advanced by 9 years. Trends of upper ocean heat content and dynamic height from the 1950s onward compare well with previously published values. Globally averaged heat content of the upper 700 m shows a nearly linear rise after the 1920s, requiring a net downward surface heat flux increase of 0.47 W m -2 into the ocean. This is close to published estimates of the increased flux required to explain the heat content increase from 1971 to 2010.
54 ENVIRONMENTAL SCIENCES↗
A low-input strategy for chromium removal from industrial stormwater using peat sorbent
Low-cost and low-input water treatment systems are important for industrial stormwater remediation. Here we examine a flow-through reactor treatment installation where water exceeds the allowable maximum concentration for drinking water in multiple metals (e.g., chromium [Cr], cadmium [Cd], zinc [Zn]) prior to treatment. Specifically, we seek to understand why Cr attenuated in the reactors is not leachable by identifying the specific chemical form of Cr and dominant mechanisms promoting sequestration in the reactors. Total solid-phase Cr concentration in the peat media ranged from 50 to 150 mg/kg after 1 yr of exposure to stormwater to 300 to 900 mg/kg after 3.5 yr. X-ray fluorescence mapping images show Cr, iron (Fe), and Zn spatially correlated over a scale of 10 μm to 5 mm. Chromium rinds form on the edges of peat particles as Cr accumulates. Chromium and Fe K-edge X-ray absorption near edge structure spectroscopy reveal chromium predominately in the 3+ oxidation state with lesser amounts of elemental Cr. We propose the primary means of chromium attenuation in the reactors is precipitation as Cr-Fe hydroxides combined with trivalent Cr adsorption onto peat surfaces.
36 MATERIALS SCIENCE↗
Influence of Heat Input and Cold Wire Feeding Rate on Pitting Corrosion Resistance of Submerged Arc Welding Duplex Stainless Steel Welds
Welding thermal cycles may severely impair duplex stainless steel (DSS) performance, especially local pitting resistance and toughness. The restricted welding energy between 0.5 and 2.5 kJ mm{sup −1} represents a limiting factor for productivity increase in DSS welding, and the addition of cold wire is an interesting alternative to increase the welding deposition rate without adding extra heat. The aim of this work is to evaluate the influence of the cold wire feeding rate (CW) and heat input (HI) on pitting corrosion behavior of DSS UNS S32304 bead-on-plate welds obtained by submerged arc welding (SAW). Cyclic potentiodynamic polarization was carried out in transverse weld sections using 1 mol L{sup −1} NaCl solution at room temperature. Most pitting corrosion spots were located on the heat-affected zone (HAZ), and the pitting potentials were lower than the base metal due to higher ferrite fractions and the presence of chromium nitrides. Considering the same CW, the HI increasing reduced E{sub pit} for 1.6, 1.9, 2.2 kJ mm{sup −1}, but increased E{sub pit} for 2.7 kJ mm{sup −1}, due to a balance between the HAZ width and the austenite fraction.
36 MATERIALS SCIENCE↗
Observer-based H{sub ∞} control for nonlinear Markovian jump systems with time-delay and input saturation
This paper focus on the problem of observer-based H{sub ∞} control for uncertain nonlinear Markovian jump systems with time-delay and actuator saturation. A delay-dependent sufficient condition is proposed which guarantees that the uncertain nonlinear Markovian jump system with time-delay and input saturation is stochastically stable via Lyapunov theory and linear matrix inequality (LMI) approach. Then, with this condition, the estimation of stability region and the design method of observer-based H{sub ∞} controller are given by solving LMIs and convex optimization problems. Finally, numerical examples are exploited to illustrate the effectiveness of the proposed method.
97 MATHEMATICS AND COMPUTING↗
H{sub ∞} memory feedback control for uncertain singular Markov jump systems with time-varying delay and input saturation
This paper concerns with the H{sub ∞} robust exponential stability and memory state feedback stabilization of singular Markov jump systems with time-delay and input saturation. Linear matrix inequality conditions are given to guarantee regularity, impulse-freeness and exponential stability for the singular Markov jump system. Moreover, sufficient conditions are presented to ensure the H{sub ∞} disturbance attenuation level, and the design method of memory feedback controller is developed by solving linear matrix inequalities optimization problem without any decompositions of system matrices and equivalent transformation. Furthermore, the function in the proof procedure belongs to multiple Lyapunov-like functions whose advantage lies in their flexibility. Finally, numerical examples are employed to verify the effectiveness of the proposed methods and to illustrate the significant improvement on the conservativeness of some reported results in the literature.
97 MATHEMATICS AND COMPUTING↗
Effect of input parameters intensity and duration on dynamic performance of MED-TVC plant
Multi-Effect-Desalination (MED) may be exposed to fluctuations (disturbances) in input parameters during operation. Therefore, there is a requirement to analyze the transient behavior of such MED systems. In this work, a dynamic model is developed and used to examine the effect of abrupt and ramp changes in the main operational parameters on the plant behavior and performance. The results show that the disturbance intensity variation has a major role in the desalination plant behavior. For the current MED-TVC configuration, it is recommended to limit the reduction in the seawater cooling flow rate to under 12% of the designed steady-state value to avoid dry out in the evaporators. Here, a reduction in the motive steam flow rate and cooling seawater temperature of more than 20% and 35% of the nominal operating values, respectively, may lead to flooding in the evaporators and a complete plant shutdown. On the other hand, the disturbance period has a minimal effect on plant performance if it avoids the critical values of the disturbance intensity that can cause plant shutdown. Simultaneous combinations of two different disturbances with opposing effects result in a modest effect on the plant operation and they can be used to control and mitigate the flooding/drying effects of the disturbances. For simultaneous combinations of disturbances with similar effect, the plant needs an accurate control system to avoid an operational shutdown.
42 ENGINEERING↗
The Role of Input Assumptions and Model Structures in Projections of Variable Renewable Energy: A Multi-Model Perspective of the U.S. Electricity System
Recent wind and solar deployment in the United States has grown at unprecedented rates, but the extent to which this growth will continue is a key question. Energy-economic planning models are often used to develop future projections of these technologies, and although it is well-understood that model outcomes are sensitive to assumptions about technology developments and market conditions, it is less clear how underlying model structures might impact outcomes. For wind and solar technologies, model structures might be an even larger driver due to the complexity required to represent their variability, uncertainty, and location-dependence. Here, we apply three state-of-the-art electric sector planning models to evaluate variable renewable generation under different conditions with both harmonized and native input assumptions to isolate the impact that model structures might have on deployment outcomes. We find growth in wind and solar deployment in all models under a business-as-usual scenario (without new policies), where the median value for variable renewable energy generation share is found to be 27% by 2050 - but with a wide range of estimates (18-43%), types of renewable technologies deployed, and regional distributions across models. With harmonized assumptions about technology costs and market conditions the range narrows slightly, but a large range in penetration outcomes remains (24-41% by 2050) suggesting that model representations play significant roles in projections of future wind and solar deployment. We also assess the implications of achieving 55% wind and solar penetration by 2050 - to assess potential challenges at higher penetration levels - and the magnitude of variable generation under a carbon-constrained future. Finally, we identify research needs to better assess the future deployment of variable renewable energy.
24 POWER TRANSMISSION AND DISTRIBUTION↗
A new approach to modeling temperature-related mortality: Non-linear autoregressive models with exogenous input
Highlights: • NARX models are established in other environmental research, but are unused in temperature-related mortality research. • NARX models do not assume any particular shape to the temperature-mortality association. • NARX models are cross-validated and are easily modified to take on real-time, multi-step-ahead predictions and hindcasts. • Year-round, daily mortality in 41 different US cities was modeled using an ensemble of NARX models in each location. • Models show skill everywhere. Results vary spatially and seasonally, improving upon a persistence model by 17% points. • When compared with distributed lag non-linear models, the output time series are largely similar Temperature-mortality relationships are nonlinear, time-lagged, and can vary depending on the time of year and geographic location, all of which limits the applicability of simple regression models in describing these associations. This research demonstrates the utility of an alternative method for modeling such complex relationships that has gained recent traction in other environmental fields: nonlinear autoregressive models with exogenous input (NARX models). All-cause mortality data and multiple temperature-based data sets were gathered from 41 different US cities, for the period 1975–2010, and subjected to ensemble NARX modeling. Models generally performed better in larger cities and during the winter season. Across the US, median absolute percentage errors were 10% (ranging from 4% to 15% in various cities), the average improvement in the r-squared over that of a simple persistence model was 17% (6–24%), and the hit rate for modeling spike days in mortality (>80th percentile) was 54% (34–71%). Mortality responded acutely to hot summer days, peaking at 0–2 days of lag before dropping precipitously, and there was an extended mortality response to cold winter days, peaking at 2–4 days of lag and dropping slowly and continuing for multiple weeks. Spring and autumn showed both of the aforementioned temperature-mortality relationships, but generally to a lesser magnitude than what was seen in summer or winter. When compared to distributed lag nonlinear models, NARX model output was nearly identical. These results highlight the applicability of NARX models for use in modeling complex and time-dependent relationships for various applications in epidemiology and environmental sciences.
54 ENVIRONMENTAL SCIENCES↗
Soil organic carbon accrual due to more efficient microbial utilization of plant inputs at greater long-term soil moisture
High long-term soil moisture may either stimulate or inhibit soil organic carbon (SOC) losses through changes to mineral and chemical composition, and resultant organo-mineral interactions. Yet, the trade-off between mineralization and accrual of SOC under long-term variation in unsaturated soil moisture remains uncertain. We tested the underexplored relationships between long-term soil moisture and organo-mineral chemical composition and its implications for SOC persistence in an experimental field in New York, USA, with differences in long-term mean soil volumetric water content (0–0.15 m depth) ranging from 0.40 to 0.63 (v/v) during the growing season. Long-term soil moisture across 20 subplots on four fallow plots were positively correlated with SOC (R 2 = 0.23; P = 0.019, n = 20), mineral-associated organic matter (MAOM) content (g fraction/g soil) (R 2 = 0.44; P = 0.001; n = 20) and occluded particulate organic matter (oPOM) content (R 2 = 0.18; P = 0.033; n = 20). Higher long-term soil moisture was associated with a decrease in the relative content of sodium pyrophosphate extractable Fe (R 2 = 0.33; P < 0.005; n = 20), an increase in sodium dithionite extractable Fe (R 2 = 0.44; P < 0.001; n = 20), and an increase in SOC retention by non-crystalline Al pools (R 2 = 0.51; P = 0.0002 for sodium pyrophosphate extracts, R 2 = 0.41; P = 0.0014 for hydroxylamine hydrochloride extracts; n = 20 for both). Increasing long-term soil moisture was associated with a four-fold increase in microbial biomass C (per unit SOC) and lower metabolic quotient (R 2 = 0.56, P < 0.001). MAOM fractions of high-moisture soils had lower C:N (from C:N 9.5 to 9.0, R 2 = 0.27, P = 0.011, n = 20). Consistent with decreasing C:N, increasing decomposition with increasing moisture was reflected by a 15% and 10% greater proportion of oxidized carboxylic-C to aromatic-C and O-alkyl C, respectively, as measured with 13 C NMR, and a more pronounced FTIR signature of N-containing proteinaceous compounds in high-moisture MAOM fractions, indicative of microbial metabolites and transformation products. A partial least squares regression showed that SOC content increased with greater long-term moisture (P = 0.019), pyrophosphate-extractable Al (P = 0.0001), and exchangeable Ca (P = 0.013). Here our results show that higher long-term soil moisture resulted in SOC accrual by enhancing conversion of plant inputs into microbial biomass that interacts with reactive minerals.
58 GEOSCIENCES↗
Gaussian wave packet transform based numerical scheme for the semi-classical Schrödinger equation with random inputs
In this work, we study the semi-classical limit of the Schrödinger equation with random inputs, and show that the semi-classical Schrödinger equation produces O(ε) oscillations in the random variable space. With the Gaussian wave packet transform, the original Schrödinger equation is mapped to an ordinary differential equation (ODE) system for the wave packet parameters coupled with a partial differential equation (PDE) for the quantity w in rescaled variables. Further, we show that the w equation does not produce ε dependent oscillations, and thus it is more amenable for numerical simulations. We propose multi-level sampling strategy in implementing the Gaussian wave packet transform, where in the most costly part, i.e. simulating the w equation, it is sufficient to use ε independent samples. We also provide extensive numerical tests as well as meaningful numerical experiments to justify the properties of the numerical algorithm, and hopefully shed light on possible future directions.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗