834 research outputs found
Performance Evaluation of a Data Validation System
Online data validation is a performance-enhancing component of modern control and health management systems. It is essential that performance of the data validation system be verified prior to its use in a control and health management system. A new Data Qualification and Validation (DQV) Test-bed application was developed to provide a systematic test environment for this performance verification. The DQV Test-bed was used to evaluate a model-based data validation package known as the Data Quality Validation Studio (DQVS). DQVS was employed as the primary data validation component of a rocket engine health management (EHM) system developed under NASA's NGLT (Next Generation Launch Technology) program. In this paper, the DQVS and DQV Test-bed software applications are described, and the DQV Test-bed verification procedure for this EHM system application is presented. Test-bed results are summarized and implications for EHM system performance improvements are discussed
Axial behavior of reinforced concrete short columns strengthened with wire rope and T-shaped steel plate units.
yesThis paper presents a relatively simple column strengthening procedure using unbonded wire rope and T-shaped steel plate units. Twelve strengthened columns and an unstrengthened control column were tested to failure under concentric axial load to explore the significance and shortcomings of the proposed strengthening technique. The main variables investigated were the volume ratio of wire ropes as well as geometrical size and configuration of T-shaped steel plates. Axial load capacity and ductility ratio of columns tested were compared with predictions obtained from the equation specified in ACI 318-05 and models developed for conventionally tied columns, respectively. The measured axial load capacities of all strengthened columns were higher than predictions obtained from ACI 318-05, indicating that the ratio of the measured and predicted values increased with the increase of volume ratio of wire ropes and flange width of T-shaped steel plates. In addition, at the same lateral reinforcement index, a much higher ductility ratio was exhibited by strengthened columns having a volume ratio of wire ropes above 0·0039 than tied columns. The ductility ratio of strengthened columns tested increased with the increase of flange width, thickness, and web height of T-shaped steel plates. A mathematical model for the prediction of stressâstrain characteristics of confined concrete using the proposed strengthening technique is developed, that was in good agreement with test results
Intraspecific and biogeographical variation in foliar fungal communities and pathogen damage of native and invasive Phragmites australis
AimRecent research has highlighted that the relationship between species interactions and latitude can differ between native and invasive plant taxa, generating biogeographical heterogeneity in community resistance to plant invasions. In the first study with foliar pathogens, we tested whether coâoccurring native and invasive lineages of common reed (Phragmites australis) exhibit nonâparallel latitudinal gradients in foliar fungal communities, pathogen susceptibility and damage, and whether these biogeographical patterns can influence the success of invasion.LocationNorth America.Time period2015â2017.Major taxa studiedPerennial grass P. australis.MethodsWe surveyed 35 P. australis field populations, spanning 17° latitude and comprising four phylogeographical lineages, including one endemic to North America and one invasive from Europe. For each population, we quantified the percentage of leaf pathogen damage and cultured fungi from diseased leaves, which we identified using molecular tools. To assess whether latitudinal gradients in pathogen damage had a genetic basis, we inoculated plants from 73 populations with four putative pathogens in a complementary common garden experiment and measured P. australis susceptibility (i.e., diseased leaf area).ResultsWe isolated 84 foliar fungal taxa. Phragmites australis lineage influenced fungal community composition but not diversity. Despite the invasive European P. australis lineage being the least susceptible to three of the four pathogens tested in the common garden experiment, pathogen damage in the field was similar between native and invasive lineages, providing no evidence that release from foliar pathogens contributes to the success of invasion. Genetically based latitudinal gradients in pathogen susceptibility observed in the common garden were isolate specific and obscured by local environmental conditions in the field, where pathogen damage was threefold higher for northern compared with southern populations, regardless of lineage.Main conclusionsOur results highlight that host plant lineage and genetically based biogeographical gradients strongly influence foliar fungal communities and pathogen susceptibility, but do not translate to patterns of pathogen damage observed in the field.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155999/1/geb13097.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155999/2/geb13097_am.pd
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Vitrification of Cesium-Laden Organic Ion Exchange Resin in a Stirred Melter
The goal of this research was a feasibility study for vitrifying the organic ion exchange resin in a stirred-tank melter. Tests were conducted to determine the fate of cesium including the feed, exit glass, and offgas streams and to assess any impact of feeding the resin on the melter or its performance
Prognostic and Health Management of Active Assets in Nuclear Power Plants
This paper presents the development of diagnostic and prognostic capabilities for active assets in nuclear power plants (NPPs). The research was performed under the Advanced Instrumentation, Information, and Control Technologies Pathway of the Light Water Reactor Sustainability Program. Idaho National Laboratory researched, developed, implemented, and demonstrated diagnostic and prognostic models for generator step-up transformers (GSUs). The Fleet-Wide Prognostic and Health Management (FW-PHM) Suite software developed by the Electric Power Research Institute was used to perform diagnosis and prognosis. As part of the research activity, Idaho National Laboratory implemented 22 GSU diagnostic models in the Asset Fault Signature Database and two wellestablished GSU prognostic models for the paper winding insulation in the Remaining Useful Life Database of the FW-PHM Suite. The implemented models along with a simulated fault data stream were used to evaluate the diagnostic and prognostic capabilities of the FW-PHM Suite. Knowledge of the operating condition of plant asset gained from diagnosis and prognosis is critical for the safe, productive, and economical long-term operation of the current fleet of NPPs. This research addresses some of the gaps in the current state of technology development and enables effective application of diagnostics and prognostics to nuclear plant assets
Measuring disease in dermatology: studies of objective and subjective methods
Itch lies second only to disturbance of body image as a reported symptom in dermatology.
This study started by concentrating on improving the measurement of itch. Itch has a paired
physical response, scratch. The pairing can be exploited: preliminary work by this unit had
validated the use of wrist-worn movement-measuring machines called âaccelerometersâ to
measure itch-related movement (scratch and rub). The first part of this research developed
use of these machines. Simple accelerometers (âActiwatch Plusâ) were used to observe the
pattern of variation of itch over clusters of nights and in different conditions. The
accelerometer scores were able to identify controlsâ scores from those with itchy disease.
Considerable variation (56%) was discovered in objective score between subject and
considerable variation was noted (46%) even within subject. More complex accelerometers,
(âDigiTracâ) which could potentially specifically identify itch-related movement on the basis
of frequency of action derived from Fast Fourier Transform (FFT), were validated against
the âgold standardâ measurement of itch-related movement, directly observed movement (via
infra red video recording). It was necessary to characterise the âfrequency of actionâ of itch
on video and, as an aside, the characteristics of human itch-related movement were
compared to other mammalsâ itch-related movement âfrequency of actionâ. The âfrequency
of actionâ and video data was used to enrich the DigiTrac readouts to improve specificity of
itch-related movement detection.
During the accelerometer studies, an unexpected finding came to light: objective score of
itch was not related to subjective score. To try to explain the lack of relationship, a 42 day
longitudinal study of atopic dermatitis patientsâ subjective and objective scores was
undertaken. The results demonstrated autocorrelation for subjective scores, but not for the
objective scores but still did not fully explain the lack of relationship.
In an effort to explain the disconnect between subjective and objective scores a second
tranche of experiments and the second part of this research interrogated whether the methods
with which we measure disease as a whole in dermatology are robust. One study
investigated whether the way patients are asked about subjective symptoms in general was
resistant to the effects of focusing and framing bias. The results were reassuring as they
suggested that the commonly used and recommended symptom scoring systems were robust
in the face of bias. In order to assess whether perspective or perception of disease explained
the disconnect, a study was designed in collaboration with the Edinburgh College of Art. A
series of computer-generated images of different psoriasis severities were created and used
to assess how doctors and patients assessed disease-extent. This study showed that, whilst
each group had a naturally divergent opinion of extent of disease, by scoring disease using
the models it was possible to unify the perspective and perception of extent. Finally, an
exploratory study to reduce recall bias to a minimum, in case this had caused the disconnect
between objective and subjective, was undertaken. This employed a novel questionnaire, the
Day Reconstruction Method
Adaptation of a Vocabulary Test from British Sign Language to American Sign Language
This study describes the adaptation process of a vocabulary knowledge test for British Sign Language (BSL) into American Sign Language (ASL) and presents results from the first round of pilot testing with twenty deaf native ASL signers. The web-based test assesses the strength of deaf childrenâs vocabulary knowledge by means of different mappings of phonological form and meaning of signs. The adaptation from BSL to ASL involved nine stages, which included forming a panel of deaf/hearing experts, developing a set of new items and revising/replacing items considered ineffective, and piloting the new version. Results provide new evidence in support of the use of this methodology for assessing sign language, making a useful contribution toward the availability of tests to assess deaf childrenâs signed
language skills
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Oak Ridge National Laboratory West End Treatment Facility simulated sludge vitrification demonstration, Revision 1
Technologies are being developed by the US Department of Energy`s (DOE) Nuclear Facility sites to convert hazardous and mixed wastes to a form suitable for permanent disposal. Vitrification, which has been declared the Best Demonstrated Available Technology for high-level radioactive waste disposal by the EPA, is capable of producing a highly durable wasteform that minimizes disposal volumes through organic destruction, moisture evaporation, and porosity reduction. However, this technology must be demonstrated over a range of waste characteristics, including compositions, chemistries, moistures, and physical characteristics to ensure that it is suitable for hazardous and mixed waste treatment. These wastes are typically wastewater treatment sludges that are categorized as listed wastes due to the process origin or organic solvent content, and usually contain only small amounts of hazardous constituents. The Oak Ridge National Laboratory`s (ORNL) West End Treatment Facility`s (WETF) sludge is considered on of these representative wastes. The WETF is a liquid waste processing plant that generates sludge from the biodenitrification and precipitation processes. An alternative wasteform is needed since the waste is currently stored in epoxy coated carbon steel tanks, which have a limited life. Since this waste has characteristics that make it suitable for vitrification with a high likelihood of success, it was identified as a suitable candidate by the Mixed Waste Integrated Program (MWIP) for testing at CU. The areas of special interest with this sludge are (1) minimum nitrates, (2) organic destruction, and (3) waste water treatment sludges containing little or no filter aid
Microfabricated Hydrogen Sensor Technology for Aerospace and Commercial Applications
Leaks on the Space Shuttle while on the Launch Pad have generated interest in hydrogen leak monitoring technology. An effective leak monitoring system requires reliable hydrogen sensors, hardware, and software to monitor the sensors. The system should process the sensor outputs and provide real-time leak monitoring information to the operator. This paper discusses the progress in developing such a complete leak monitoring system. Advanced microfabricated hydrogen sensors are being fabricated at Case Western Reserve University (CWRU) and tested at NASA Lewis Research Center (LeRC) and Gencorp Aerojet (Aerojet). Changes in the hydrogen concentrations are detected using a PdAg on silicon Schottky diode structure. Sensor temperature control is achieved with a temperature sensor and heater fabricated onto the sensor chip. Results of the characterization of these sensors are presented. These sensors can detect low concentrations of hydrogen in inert environments with high sensitivity and quick response time. Aerojet is developing the hardware and software for a multipoint leak monitoring system designed to provide leak source and magnitude information in real time. The monitoring system processes data from the hydrogen sensors and presents the operator with a visual indication of the leak location and magnitude. Work has commenced on integrating the NASA LeRC-CWRU hydrogen sensors with the Aerojet designed monitoring system. Although the leak monitoring system was designed for hydrogen propulsion systems, the possible applications of this monitoring system are wide ranged. Possible commercialization of the system will also be discussed
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