1,195 research outputs found
Pressure Relief Devices for High-Pressure Gaseous Storage Systems: Applicability to Hydrogen Technology
Pressure relief devices (PRDs) are viewed as essential safety measures for high-pressure gas storage and distribution systems. These devices are used to prevent the over-pressurization of gas storage vessels and distribution equipment, except in the application of certain toxic gases. PRDs play a critical role in the implementation of most high-pressure gas storage systems and anyone working with these devices should understand their function so they can be designed, installed, and maintained properly to prevent any potentially dangerous or fatal incidents. As such, the intention of this report is to introduce the reader to the function of the common types of PRDs currently used in industry. Since high-pressure hydrogen gas storage systems are being developed to support the growing hydrogen energy infrastructure, several recent failure incidents, specifically involving hydrogen, will be examined to demonstrate the results and possible mechanisms of a device failure. The applicable codes and standards, developed to minimize the risk of failure for PRDs, will also be reviewed. Finally, because PRDs are a critical component for the development of a successful hydrogen energy infrastructure, important considerations for pressure relief devices applied in a hydrogen gas environment will be explored
Paper Session I-B - An Evaluation of Electronic Nose for Space Program Applications
The ability to monitor air contaminants in the Shuttle and the International Space Station is important to ensure the health and safety of astronauts. Three specific space applications have been identified that would benefit from a chemical monitor: organic contaminants in crew cabins, propellant contaminants in the airlock, and pre-combustion fire detection. NASA has assessed several commercial and developing electronic noses (e-noses) for these applications. A preliminary series of tests identified those e-noses that exhibited sufficient sensitivity to the vapors of interest. These e-noses were further tested to assess their ability to identify vapors, and in-house software has been developed to enhance identification. This paper describes the tests, the classification ability of selected e-noses, and the software improvements made to meet the requirements for these space program applications
Knowing no fear
People with brain injuries involving the amygdala are often poor at recognizing facial expressions of fear, but the extent to which this impairment compromises other signals of the emotion of fear has not been clearly established. We investigated N.M., a person with bilateral amygdala damage and a left thalamic lesion, who was impaired at recognizing fear from facial expressions. N.M. showed an equivalent deficit affecting fear recognition from body postures and emotional sounds. His deficit of fear recognition was not linked to evidence of any problem in recognizing anger (a common feature in other reports), but for his everyday experience of emotion N.M. reported reduced anger and fear compared with neurologically normal controls. These findings show a specific deficit compromising the recognition of the emotion of fear from a wide range of social signals, and suggest a possible relationship of this type of impairment with alterations of emotional experience
Codes and Standards Requirements for Deployment of Emerging Fuel Cell Technologies
The objective of this NREL report is to provide information on codes and standards (of two emerging hydrogen power fuel cell technology markets; forklift trucks and backup power units), that would ease the implementation of emerging fuel cell technologies. This information should help project developers, project engineers, code officials and other interested parties in developing and reviewing permit applications for regulatory compliance
Analysis of Swine Movements in a Province in Northern Vietnam and Application in the Design of Surveillance Strategies for Infectious Diseases
While swine production is rapidly growing in South-East Asia, the structure of the swine industry and the dynamic of pig movements have not been well-studied. However, this knowledge is a prerequisite for understanding the dynamic of disease transmission in swine populations and designing cost-effective surveillance strategies for infectious diseases. In this study, we assessed the farming and trading practices in the Vietnamese swine familial farming sector, which accounts for most pigs in Vietnam, and for which disease surveillance is a major challenge. Farmers from two communes of a Red River Delta Province (northern Vietnam) were interviewed, along with traders involved in pig transactions. Major differences in the trade structure were observed between the two communes. One commune had mainly transversal trades, that is between farms of equivalent sizes, whereas the other had pyramidal trades, that is from larger to smaller farms. Companies and large familial farrow-to-finish farms were likely to act as major sources of disease spread through pig sales, demonstrating their importance for disease control. Familial fattening farms with high pig purchases were at greater risk of disease introduction and should be targeted for disease detection as part of a risk-based surveillance. In contrast, many other familial farms were isolated or weakly connected to the swine trade network limiting their relevance for surveillance activities. However, some of these farms used boar hiring for breeding, increasing the risk of disease spread. Most familial farms were slaughtering pigs at the farm or in small local slaughterhouses, making the surveillance at the slaughterhouse inefficient. In terms of spatial distribution of the trades, the results suggested that northern provinces were highly connected and showed some connection with central and southern provinces. These results are useful to develop risk-based surveillance protocols for disease detection in the swine familial sector and to make recommendations for disease control. (Résumé d'auteur
Summary and Findings from the NREL/DOE Hydrogen Sensor Workshop (June 8, 2011)
On June 8, 2011, DOE/NREL hosted a hydrogen sensor workshop attended by nearly forty participants from private organizations, government facilities, and academic institutions . The workshop participants represented a cross section of stakeholders in the hydrogen community, including sensor developers, end users, site safety officials, and code and standards developers. The goals of the workshop were to identify critical applications for the emerging hydrogen infrastructure that require or would benefit from hydrogen sensors, to assign performance specifications for sensor deployed in each application, and to identify shortcomings or deficiencies (i.e., technical gaps) in the ability of current sensor technology to meet the assigned performance requirements
Conduit flow experiments help constraining the regime of explosive eruptions
It is currently impractical to measure what happens in a volcano during an explosive
eruption, and up to now much of our knowledge depends on theoretical models. Here we
show, by means of large‐scale experiments, that the regime of explosive events can be
constrained on the basis of the characteristics of magma at the point of fragmentation
and conduit geometry. Our model, whose results are consistent with the literature, is a
simple tool for defining the conditions at conduit exit that control the most hazardous
volcanic regimes. Besides the well‐known convective plume regime, which generates
pyroclastic fallout, and the vertically collapsing column regime, which leads to pyroclastic
flows, we introduce an additional regime of radially expanding columns, which form when
the eruptive gas‐particle mixture exits from the vent at overpressure with respect to
atmosphere. As a consequence of the radial expansion, a dilute collapse occurs, which
favors the formation of density currents resembling natural base surges. We conclude that
a quantitative knowledge of magma fragmentation, i.e., particle size, fragmentation
energy, and fragmentation speed, is critical for determining the eruption regime.Research was partially funded by DPC-INGV
agreement 07‐09 and MUR PRIN 06.PublishedB042043.6. Fisica del vulcanismoJCR Journalrestricte
A Crystal Structure of the Bifunctional Antibiotic Simocyclinone D8, Bound to DNA Gyrase
Simocyclinones are bifunctional antibiotics that inhibit bacterial DNA gyrase by preventing DNA binding to the enzyme. We report the crystal structure of the complex formed between the N-terminal domain of the Escherichia coli gyrase A subunit and simocyclinone D8, revealing two binding pockets that separately accommodate the aminocoumarin and polyketide moieties of the antibiotic. These are close to, but distinct from, the quinolone-binding site, consistent with our observations that several mutations in this region confer resistance to both agents. Biochemical studies show that the individual moieties of simocyclinone D8 are comparatively weak inhibitors of gyrase relative to the parent compound, but their combination generates a more potent inhibitor. Our results should facilitate the design of drug molecules that target these unexploited binding pockets
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Field-usable portable analyzer for chlorinated organic compounds
In 1992, a chemical sensor was developed which showed almost perfect selectivity to vapors of chlorinated solvents. When interfaced to an instrument, a chemical analyzer will be produced that has near- absolute selectivity to vapors of volatile chlorinated organic compounds. TRI has just completed the second of a 2-phase program to develop this new instrument system, which is called the RCL MONITOR. In Phase II, this instrument was deployed in 5 EM40 operations. Phase II applications covered clean-up process monitoring, environmental modeling, routine monitoring, health and safety, and technology validation. Vapor levels between 0 and 100 ppM can be determined in 90 s with a lower detection limit of 0.5 ppM using the hand-portable instrument. Based on the favorable performance of the RCL MONITOR, the commercial instrument was released for commercial sales on Sept. 20, 1996
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