SEARCH · Search NASA

Results for “COMPENSATION”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,603 records · Page 89

All sources NASA NTRS DOE OSTI

NASA NTRS2018

The Evaluation of Cryogenic Force Balance Calibration Methodologies with Respect to Wind Tunnel Results

Independent tests of the NASA Common Research Model (CRM) at NASA's National Transonic Facility (NTF) and the European Transonic Windtunnel (ETW) revealed discrepancies at low operating temperatures and high Reynolds numbers that warranted further investigation. Since each facility used their own force balance for their tunnel entry, one suggestion for the discrepancy was the temperature compensation methodology developed and applied for each balance. This hypothesis is explored through simulation and experimentally. Independent calibrations of NASA's NTF-118A balance at NASA Langley and ETW reveal discrepancies in the thermal compensation of the normal force and pitching moment primary sensitivities with temperature, while the axial force primary sensitivities are in good agreement. The application of the force balance calibrations performed at NASA and ETW to the prior wind tunnel data suggests that the thermal compensation discrepancies are an order of magnitude less than the discrepancies observed between the wind tunnel aerodynamic coefficients.

Burns, Devin E.↗

NASA NTRSDate not supplied

Robust Path-following Controller for Multirotor Vehicles in Uncertain Wind Conditions

This paper presents simulations of L1 adaptive controller on a multirotor vehicle for compensation of convective winds. There are increasing efforts to utilize unmanned vehicles for fighting wildfires, but such vehicles need to be able to compensate for convective updrafts and other uncertainties (e.g., wind shear and turbulence) caused by the wildfire. Other application domains, such as urban air mobility, also must account for convective or uncertain winds present in urban microclimates. Geometric controllers have great tracking performance properties in environments without uncertainties, but the tracking performance degrades when wind disturbances and external loads are present in the environment. Introducing L1 adaptive control into the controller architecture compensates for these wind disturbances and reduces the tracking error caused by such disturbances. The controller architecture is implemented on a small quadrotor. The simulations demonstrate the advantages of the L1 adaptive augmentation for a sample figure-eight trajectory while encountering unknown variable wind conditions with an external load.

John L Bullock↗

NASA NTRSDate not supplied

Robust Path-following Controller for Multirotor Vehicles in Uncertain Wind Conditions

John Bullock↗

DOE OSTI2015

Photon detector configured to employ the Gunn effect and method of use

Embodiments disclosed herein relate to photon detectors configured to employ the Gunn effect for detecting high-energy photons (e.g., x-rays and gamma rays) and methods of use. In an embodiment, a photon detector for detecting high-energy photons is disclosed. The photon detector includes a p-i-n semiconductor diode having a p-type semiconductor region, an n-type semiconductor region, and a compensated i-region disposed between the p-type semiconductor region and the n-type semiconductor region. The compensated i-region and has a width of about 100 .mu.m to about 400 .mu.m and is configured to exhibit the Gunn effect when the p-i-n semiconductor diode is forward biased a sufficient amount. The compensated i-region is doped to include a free carrier concentration of less than about 10.sup.10 cm.sup.-3.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2015

Method and apparatus for control of coherent synchrotron radiation effects during recirculation with bunch compression

A modulated-bending recirculating system that avoids CSR-driven breakdown in emittance compensation by redistributing the bending along the beamline. The modulated-bending recirculating system includes a) larger angles of bending in initial FODO cells, thereby enhancing the impact of CSR early on in the beam line while the bunch is long, and 2) a decreased bending angle in the final FODO cells, reducing the effect of CSR while the bunch is short. The invention describes a method for controlling the effects of CSR during recirculation and bunch compression including a) correcting chromatic aberrations, b) correcting lattice and CSR-induced curvature in the longitudinal phase space by compensating T.sub.566, and c) using lattice perturbations to compensate obvious linear correlations x-dp/p and x'-dp/p.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2016

Athermalization of resonant optical devices via thermo-mechanical feedback

A passively athermal photonic system including a photonic circuit having a substrate and an optical cavity defined on the substrate, and passive temperature-responsive provisions for inducing strain in the optical cavity of the photonic circuit to compensate for a thermo-optic effect resulting from a temperature change in the optical cavity of the photonic circuit. Also disclosed is a method of passively compensating for a temperature dependent thermo-optic effect resulting on an optical cavity of a photonic circuit including the step of passively inducing strain in the optical cavity as a function of a temperature change of the optical cavity thereby producing an elasto-optic effect in the optical cavity to compensate for the thermo-optic effect resulting on an optical cavity due to the temperature change.

36 MATERIALS SCIENCE↗

DOE OSTI2017

Observed Temperature Effects on Load Cells

Researchers at Oak Ridge National Laboratory subjected load cells to a range of temperatures beyond their compensated range to characterize the temperature effect on the minimum dead load output over their entire operating temperature range. In modern front-end nuclear fuel cycle facilities, load cells are often used in UF6 feed and withdrawal stations to monitor the material being fed to or withdrawn from the cylinders. Load cells exhibit some temperature dependence; however, manufacturers try to minimize temperature effects by compensating load cells over a range of temperatures (typically from -10 °C to +40 °C (+14 °F to +104 °F)). Load cells in modern UF6 feed and withdrawal stations tend to operate beyond this range: down to -25 °C and up to 80 °C (-13 °F to 176 °F). While load cell data sheets often include specifications for the temperature effect on the minimum dead load output and the sensitivity over the compensated range, they do not include specifications for expected effects outside of this range. In this paper, we discuss our test setup and preliminary results of testing load cells representative of those that may be used in UF6 feed and withdrawal stations.

Mattingly, Gavin↗

DOE OSTI2020

Method and system to separate optically measured coupled parameters

A system includes a first optical sensor sensitive to both a parameter of interest, Parameter1, and at least one confounding parameter, Parameter2 and a second optical sensor sensitive only to the confounding parameter. Measurement circuitry measures M1 in response to light scattered by the first optical sensor, where M1=value of Parameter1+K*value of Parameter2. The measurement circuitry also measures M2 in response to light scattered by the second optical sensor, where M2=value of Parameter2. Compensation circuitry determines a compensation factor, K, for the confounding parameter based on measurements of M1 and M2 taken over multiple load/unload cycles or over one or more thermal cycles. The compensation factor is used to determine the parameter of interest.

Ganguli, Anurag↗

DOE OSTI2023

The Mitigation Hierarchy

The mitigation hierarchy is a widely used framework to inform conservation decisions. The hierarchy offers a structured set of steps for how projects can lessen negative impacts or lead to an increase in biodiversity. In its simplest form, the mitigation hierarchy includes three stages: (1) avoid creating impacts from the outset, (2) minimize the impacts that cannot be avoided, and (3) compensate for or offset the impacts that cannot be minimized. Proper application of the hierarchy should decrease impacts of the project over time, such that most of the impact is alleviated through avoidance, leaving a modest amount remaining to minimize, and only a residual to compensate. In practice, avoidance should be prioritized and can be a cost-effective means of mitigation. Whereas compensation should be considered the lowest priority and should only be applied in situations in which the previous mitigation steps were unable to fully alleviate undesirable impacts.

biodiversity↗

DOE OSTI2023

La Jerarquia de Mitigacion (Spanish)

biodiversity↗

DOE OSTI2016

Model Calibration vs. Physics-guided Coverage Mapping: Case Study - Pressure Drop Calculations

This work deals with a fundamental question in model validation: given a body of available experiments and an envisaged domain of nuclear reactor operating conditions (referred to as the reactor application), how can one develop a quantitative approach that measures the portion of the prior uncertainties of the reactor application that is covered by the available experiments? Coverage here means that the uncertainties of the reactor application are originating from and behaving in exactly the same way as those observed at the experimental conditions. This approach is valuable as it provides a scientifically defendable criterion by which experimentally measured biases can be credibly extrapolated (i.e., mapped) to biases for the reactor applications. This work focuses on the application of a new methodology, referred to as physics-guided coverage mapping (PCM), to the estimation of hydraulic pressure losses in reactor pipes. PCM provides a generic, calibration-free approach to the mapping of experimental biases by relying on high fidelity physics simulation and information theoretic measure how much of the application domain is covered by the experiments. The idea is to employ the physics models to establish a joint probability distribution that relates the application and the available body of experiments. An information-theoretic measure, referred to as the mutual information, is used to calculate a quantitative metric that measures the inter-dependence between the application and the experiment. A virtual experiment is employed to demonstrate the application of PCM, wherein the pressure drop is calculated for both the experiment and the application using two different flow conditions, i.e., laminar and turbulent, and the experimental values are simulated. All parameters introducing uncertainties, such as geometry, friction factor formulas and their associated parameters are also incorporated. The results obtained with PCM are compared to a conventional calibration-based approach. This work show that the proposed approach can circumvent a number of challenges that face calibration-based methods, such as nonlinearity, ill-posedness and error compensation in high dimensional models with many parameters. This work focus primarily in this summary on parameter uncertainties and how they can be treated using PCM. In a separate summary, discuss performance of PCM under the presence of modeling uncertainties. This simple study has shown that calibration techniques for very simple situations cannot correctly scale the measurements from the experimental to the application domain. It is our view that is occurs primarily due the phenomenon of error compensation where on artificially changes the value of selected parameters to account for all sources of uncertainties. The situation gets more complicated when one calibrates multiple parameters where now the problem could potentially have an infinite number of ways by which the errors can be compensated. (authors)

42 ENGINEERING↗

DOE OSTI2019

Successful Implementation of a Natural Resource Restoration Plan at the Fernald Preserve - 19568

The Fernald Preserve, Ohio, Site is a former uranium-processing plant that underwent extensive remediation pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). It is situated on a 425-hectare (ha) (1050-acre) tract of land, approximately 29 kilometers (km) (18 miles) northwest of Cincinnati, Ohio. The US Department of Energy (DOE) Office of Legacy Management is responsible for management of the site. Site remediation and subsequent ecological restoration have converted the site from an industrial production facility to an undeveloped park, encompassing a series of wetlands, prairies, and forested communities. The remediation of buildings and contaminated soil was completed in 2006, but aquifer remediation is ongoing. Portions of the site are open to the public, including approximately 11 km (7 miles) of walking trails that are open year-round and a Fernald Preserve Visitors Center open four days a week. Stakeholders were instrumental in providing recommendations for final land use of the site as an undeveloped park with an emphasis on wildlife. Final land use decisions were also instrumental in the resolution of a CERCLA natural resource damage claim. The State of Ohio sued DOE in 1986 for damages to state natural resources under Section 107 of CERCLA. The suit was stayed until completion of all Records of Decision (RODs) for the site. The last ROD was signed in 1996. DOE, which was both a Natural Resource Trustee (NRT) and a potentially responsible party (PRP) under CERCLA, initiated consultation with other site NRTs in 1993. A Trustee Council was formed that included DOE, Ohio Environmental Protection Agency (representing the State of Ohio), and the US Fish and Wildlife Service (representing the US Department of the Interior). The NRTs agreed collectively to conduct sitewide ecological restoration, consistent with the stakeholder vision of final land use. A conceptual restoration plan was drafted in 1998. This Natural Resource Restoration Plan (NRRP) developed goals for site restoration, as well as provisions for monitoring and maintenance of restored areas. The NRTs signed a Memorandum of Understanding in 2001, and DOE integrated ecological restoration design and construction into remediation and closure activities for the site. The NRT relationship became contentious in the following years as a result of a disagreement over monitoring commitments and compensation for groundwater injury. Final settlement was reached in 2008. As part of the settlement, DOE paid $13.75 million into the NRT fund as compensation for natural resource damages. In addition, the NRRP was finalized, and long-term commitments for monitoring and maintenance of ecologically restored areas were put in place. An Environmental Covenant was established and recorded with Hamilton and Butler Counties that ensures site activity and use limitations remain in place. The NRTs used a portion of the settlement funds to initiate the Paddys Run Conservation Project. This effort is a means to secure development rights and conservation easements within the Paddys Run watershed. Paddys Run is a third-order stream located on the western side of the Fernald Preserve. The NRTs partnered with Three Valley Conservation Trust to obtain assistance with land acquisition and conservation easement management, and since the program's inception in the Fall of 2012, more than 1820 ha (4500 acres) have been permanently protected via easement or purchase. Future decisions by the NRTs regarding monitoring and maintenance of restored areas will be negotiated in 2020. The site Restored Area Maintenance Plan (RAMP) was developed in 2010. The RAMP is a requirement within the NRRP and is scheduled for review following 10 years of implementation. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2014

Aircrew, Cancer and Probability of Causation - Paper 60

Aircrew are radiation workers who normally are not provided with dosimetry. The Energy Employees Occupational Illness Compensation Policy Act (EEOICPA) established an important legal precedent that fundamentally changed employer liability for companies that expose workers to radiation. We have applied the method used by EEOICPA (Interactive Radio Epidemiological Program (IREP)) to cancers found in excess in published epidemiological studies of aircrew. Our results show that from 4 to 8 of the 12 cancers reported in the literature in typical aircrew may be compensable using EEOICPA methods. The other cancers may be compensable as well, given an unusual flight career with greater exposures than typical. Our research demonstrates there are cancers that have a 50% POC at annual exposures within the range of those asserted by the FAA for aircrew. The FAA currently estimates aircrew annual exposure as up to 6 mSv from GCR alone. While dosimetry is urgently needed for existing aircrew, historical dose reconstructions will be needed to address POC for aircrew diagnosed with a radiogenic cancer. (authors)

61 RADIATION PROTECTION AND DOSIMETRY↗

DOE OSTI2024

How to Safely Build 100-plus Kilograms of Weapons-Grade Plutonium

The goal of the EUCLID (Experiments Underpinned by Computational Learning for Improvements in Nuclear Data) project was to reduce compensating errors by utilizing machine learning to both help determine which reactions contain compensating errors as well as optimizing an experiment which can be used to maximally reduce these errors. Compensating errors can adversely impact the predictive power of application simulations, and therefore it’s useful to further constrain nuclear data and reduce these errors. The EUCLID project included building two configurations at the National Criticality Experiments Research Center (NCERC). These two configurations had very different geometries (one was cube-like and one was slab-like). Previous works focus on selection of the target experiment(s), radiation transport capabilities developed in the project, the experiment optimization, and the performance of the experiments. This work will focus only on the safety aspects of performing this experiment, which utilized over 100 kg of weapons-grade plutonium.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2016

Utah FORGE: Well 14-2 Logs and Data from Roosevelt Hot Spring Area

This is a compilation of logs and data from Well 14-2 in the Roosevelt Hot Springs area in Utah. This well is also in the Utah FORGE study area. Data includes: flowmeter survey (1989), geochemistry (1977-1978, 1977-1983), injection test data (1979, 1982), and spinner surveys (1989, 1985-1986). Logs include: borehole compensated sonic and gamma ray (600'-6112'), borehole geometry and gamma ray (50'-4829'), caliper (0'-1720'), compensated neutron formation density (600'-6121'), induction electric (650'-6118'), mud log (79'-6100'), steam injection survey (50'-1175'), subsurface pressure surveys (0'-6087'), and subsurface temperature surveys (0'-6106'). The file is in a compressed .zip format and there is a data inventory table (Excel spreadsheet) in the root folder that is a guide to the data that is accessible in subfolders.

14-2↗

DOE OSTI2015

Scalable Heuristics for Planning, Placement and Sizing of Flexible AC Transmission System Devices

Aiming to relieve transmission grid congestion and improve or extend feasibility domain of the operations, we build optimization heuristics, generalizing standard AC Optimal Power Flow (OPF), for placement and sizing of Flexible Alternating Current Transmission System (FACTS) devices of the Series Compensation (SC) and Static VAR Compensation (SVC) type. One use of these devices is in resolving the case when the AC OPF solution does not exist because of congestion. Another application is developing a long-term investment strategy for placement and sizing of the SC and SVC devices to reduce operational cost and improve power system operation. SC and SVC devices are represented by modification of the transmission line inductances and reactive power nodal corrections respectively. We find one placement and sizing of FACTs devices for multiple scenarios and optimal settings for each scenario simultaneously. Our solution of the nonlinear and nonconvex generalized AC-OPF consists of building a convergent sequence of convex optimizations containing only linear constraints and shows good computational scaling to larger systems. The approach is illustrated on single- and multi-scenario examples of the Matpower case-30 model.

24 POWER TRANSMISSION AND DISTRIBUTION↗

DOE OSTI2018

Native Vacancy Enhanced Oxygen Redox Reversibility and Structural Robustness

Cathode materials with high energy density, long cycle life, and low cost are of top priority for energy storage systems. The Li–rich transition metal (TM) oxides achieve high specific capacities by redox reactions of both the TM and oxygen ions. However, the poor reversible redox reaction of the anions results in severe fading of the cycling performance. Herein, the vacancy–containing Na 4/7 [Mn 6/7 (Mn) 1/7 ]O 2 (Mn for vacancies in the Mn—O slab) is presented as a novel cathode material for Na–ion batteries. The presence of native vacancies endows this material with attractive properties including high structural flexibility and stability upon Na–ion extraction and insertion and high reversibility of oxygen redox reaction. Synchrotron X–ray absorption near edge structure and X–ray photoelectron spectroscopy studies demonstrate that the charge compensation is dominated by the oxygen redox reaction and Mn 3+ /Mn 4+ redox reaction separately. In situ synchrotron X–ray diffraction exhibits its zero–strain feature during the cycling. Density functional theory calculations further deepen the understanding of the charge compensation by oxygen and manganese redox reactions and the immobility of the Mn ions in the material. Furthermore, these findings provide new ideas on searching for and designing materials with high capacity and high structural stability for novel energy storage systems.

25 ENERGY STORAGE↗

DOE OSTI2023

Adaptive changes in sexual behavior in the high–risk population in response to human monkeypox transmission in Canada can help control the outbreak: Insights from a two–group, two–route epidemic model

Monkeypox, a zoonotic disease, is emerging as a potential sexually transmitted infection/disease, with underlying transmission mechanisms still unclear. We devised a risk-structured, compartmental model, incorporating sexual behavior dynamics. We compared different strategies targeting the high-risk population: a scenario of control policies geared toward the use of condoms and/or sexual abstinence (robust control strategy) with risk compensation behavior change, and a scenario of control strategies with behavior change in response to the doubling rate (adaptive control strategy). Monkeypox's basic reproduction number is 1.464, 0.0066, and 1.461 in the high-risk, low-risk, and total populations, respectively, with the high-risk group being the major driver of monkeypox spread. Policies imposing condom use or sexual abstinence need to achieve a 35% minimum compliance rate to stop further transmission, while a combination of both can curb the spread with 10% compliance to abstinence and 25% to condom use. With risk compensation, the only option is to impose sexual abstinence by at least 35%. Adaptive control is more effective than robust control where the daily sexual contact number is reduced proportionally and remains constant thereafter, shortening the time to epidemic peak, lowering its size, facilitating disease attenuation, and playing a key role in controlling the current outbreak.

60 APPLIED LIFE SCIENCES↗