WorldWideScience

Sample records for characterizing propagule pressure

  1. Effects of vegetative propagule pressure on the establishment of an introduced clonal plant, Hydrocotyle vulgaris

    OpenAIRE

    Ruihua Liu; Qiuwen Chen; Bicheng Dong; Feihai Yu

    2014-01-01

    Some introduced clonal plants spread mainly by vegetative (clonal) propagules due to the absence of sexual reproduction in the introduced range. Propagule pressure (i.e. total number of propagules) may affect the establishment and thus invasion success of introduced clonal plants, and such effects may also depend on habitat conditions. A greenhouse experiment with an introduced plant, Hydrocotyle vulgaris was conducted to investigate the role of propagule pressure on its invasion process. Hig...

  2. Effects of vegetative propagule pressure on the establishment of an introduced clonal plant, Hydrocotyle vulgaris.

    Science.gov (United States)

    Liu, Ruihua; Chen, Qiuwen; Dong, Bicheng; Yu, Feihai

    2014-01-01

    Some introduced clonal plants spread mainly by vegetative (clonal) propagules due to the absence of sexual reproduction in the introduced range. Propagule pressure (i.e. total number of propagules) may affect the establishment and thus invasion success of introduced clonal plants, and such effects may also depend on habitat conditions. A greenhouse experiment with an introduced plant, Hydrocotyle vulgaris was conducted to investigate the role of propagule pressure on its invasion process. High (five ramets) or low (one ramet) propagule pressure was established either in bare soil or in an experimental plant community consisting of four grassland species. H. vulgaris produced more total biomass under high than under low propagule pressure in both habitat conditions. Interestingly, the size of the H. vulgaris individuals was smaller under high than under low propagule pressure in bare soil, whereas it did not differ between the two propagule pressure treatments in the grassland community. The results indicated that high propagule pressure can ensure the successful invasion in either the grass community or bare soil, and the shift in the intraspecific interaction of H. vulgaris from competition in the bare soil to facilitation in the grassland community may be a potential mechanism. PMID:24981102

  3. Propagule pressure, habitat conditions and clonal integration influence the establishment and growth of an invasive clonal plant, Alternanthera philoxeroides

    OpenAIRE

    Wen-Hua eYou; Cui-min eHan; Long-xiang eFang; Dao-lin eDu

    2016-01-01

    Many notorious invasive plants are clonal, spreading mainly by vegetative propagules. Propagule pressure (the number of propagules) may affect the establishment, growth and thus invasion success of these clonal plants, and such effects may also depend on habitat conditions. To understand how propagule pressure, habitat conditions and clonal integration affect the establishment and growth of the invasive clonal plants, an 8-week greenhouse with an invasive clonal plant, Alternanthera philoxero...

  4. Propagule Pressure, Habitat Conditions and Clonal Integration Influence the Establishment and Growth of an Invasive Clonal Plant, Alternanthera philoxeroides

    OpenAIRE

    You, Wen-Hua; Han, Cui-Min; Fang, Long-Xiang; Du, Dao-Lin

    2016-01-01

    Many notorious invasive plants are clonal, spreading mainly by vegetative propagules. Propagule pressure (the number of propagules) may affect the establishment, growth, and thus invasion success of these clonal plants, and such effects may also depend on habitat conditions. To understand how propagule pressure, habitat conditions and clonal integration affect the establishment and growth of the invasive clonal plants, an 8-week greenhouse with an invasive clonal plant, Alternanthera philoxer...

  5. Propagule Pressure, Habitat Conditions and Clonal Integration Influence the Establishment and Growth of an Invasive Clonal Plant, Alternanthera philoxeroides.

    Science.gov (United States)

    You, Wen-Hua; Han, Cui-Min; Fang, Long-Xiang; Du, Dao-Lin

    2016-01-01

    Many notorious invasive plants are clonal, spreading mainly by vegetative propagules. Propagule pressure (the number of propagules) may affect the establishment, growth, and thus invasion success of these clonal plants, and such effects may also depend on habitat conditions. To understand how propagule pressure, habitat conditions and clonal integration affect the establishment and growth of the invasive clonal plants, an 8-week greenhouse with an invasive clonal plant, Alternanthera philoxeroides was conducted. High (five fragments) or low (one fragment) propagule pressure was established either in bare soil (open habitat) or dense native vegetation of Jussiaea repens (vegetative habitat), with the stolon connections either severed from or connected to the relatively older ramets. High propagule pressure greatly increased the establishment and growth of A. philoxeroides, especially when it grew in vegetative habitats. Surprisingly, high propagule pressure significantly reduced the growth of individual plants of A. philoxeroides in open habitats, whereas it did not affect the individual growth in vegetative habitats. A shift in the intraspecific interaction on A. philoxeroides from competition in open habitats to facilitation in vegetative habitats may be the main reason. Moreover, clonal integration significantly improved the growth of A. philoxeroides only in open habitats, especially with low propagule pressure, whereas it had no effects on the growth and competitive ability of A. philoxeroides in vegetative habitats, suggesting that clonal integration may be of most important for A. philoxeroides to explore new open space and spread. These findings suggest that propagule pressure may be crucial for the invasion success of A. philoxeroides, and such an effect also depends on habitat conditions. PMID:27200041

  6. The role of propagule pressure, genetic diversity and microsite availability for Senecio vernalis invasion.

    Directory of Open Access Journals (Sweden)

    Alexandra Erfmeier

    Full Text Available Genetic diversity is supposed to support the colonization success of expanding species, in particular in situations where microsite availability is constrained. Addressing the role of genetic diversity in plant invasion experimentally requires its manipulation independent of propagule pressure. To assess the relative importance of these components for the invasion of Senecio vernalis, we created propagule mixtures of four levels of genotype diversity by combining seeds across remote populations, across proximate populations, within single populations and within seed families. In a first container experiment with constant Festuca rupicola density as matrix, genotype diversity was crossed with three levels of seed density. In a second experiment, we tested for effects of establishment limitation and genotype diversity by manipulating Festuca densities. Increasing genetic diversity had no effects on abundance and biomass of S. vernalis but positively affected the proportion of large individuals to small individuals. Mixtures composed from proximate populations had a significantly higher proportion of large individuals than mixtures composed from within seed families only. High propagule pressure increased emergence and establishment of S. vernalis but had no effect on individual growth performance. Establishment was favoured in containers with Festuca, but performance of surviving seedlings was higher in open soil treatments. For S. vernalis invasion, we found a shift in driving factors from density dependence to effects of genetic diversity across life stages. While initial abundance was mostly linked to the amount of seed input, genetic diversity, in contrast, affected later stages of colonization probably via sampling effects and seemed to contribute to filtering the genotypes that finally grew up. In consequence, when disentangling the mechanistic relationships of genetic diversity, seed density and microsite limitation in colonization of

  7. The role of propagule pressure, genetic diversity and microsite availability for Senecio vernalis invasion.

    Science.gov (United States)

    Erfmeier, Alexandra; Hantsch, Lydia; Bruelheide, Helge

    2013-01-01

    Genetic diversity is supposed to support the colonization success of expanding species, in particular in situations where microsite availability is constrained. Addressing the role of genetic diversity in plant invasion experimentally requires its manipulation independent of propagule pressure. To assess the relative importance of these components for the invasion of Senecio vernalis, we created propagule mixtures of four levels of genotype diversity by combining seeds across remote populations, across proximate populations, within single populations and within seed families. In a first container experiment with constant Festuca rupicola density as matrix, genotype diversity was crossed with three levels of seed density. In a second experiment, we tested for effects of establishment limitation and genotype diversity by manipulating Festuca densities. Increasing genetic diversity had no effects on abundance and biomass of S. vernalis but positively affected the proportion of large individuals to small individuals. Mixtures composed from proximate populations had a significantly higher proportion of large individuals than mixtures composed from within seed families only. High propagule pressure increased emergence and establishment of S. vernalis but had no effect on individual growth performance. Establishment was favoured in containers with Festuca, but performance of surviving seedlings was higher in open soil treatments. For S. vernalis invasion, we found a shift in driving factors from density dependence to effects of genetic diversity across life stages. While initial abundance was mostly linked to the amount of seed input, genetic diversity, in contrast, affected later stages of colonization probably via sampling effects and seemed to contribute to filtering the genotypes that finally grew up. In consequence, when disentangling the mechanistic relationships of genetic diversity, seed density and microsite limitation in colonization of invasive plants, a clear

  8. Manipulating alien plant species propagule pressure as a prevention strategy for protected areasimpacts of alien plant invasions in protected areas

    Czech Academy of Sciences Publication Activity Database

    Meyerson, L. A.; Pyšek, Petr

    Dordrecht: Springer Science+Business Media, 2013 - (Foxcroft, L.; Pyšek, P.; Richardson, D.; Genovesi, P.), s. 473-486. (Book series: Invading Nature-Springer Series in Invasion Ecology). ISBN 978-94-007-7749-1 Institutional support: RVO:67985939 Keywords : plant invasions * protected areas * propagule pressure Subject RIV: EH - Ecology, Behaviour

  9. Naturalization of central European plants in North America: species traits, habitats, propagule pressure, residence time.

    Science.gov (United States)

    Pyšek, Petr; Manceur, Ameur M; Alba, Christina; McGregor, Kirsty F; Pergl, Jan; Stajerová, Katerina; Chytrý, Milan; Danihelka, Jiří; Kartesz, John; Klimesova, Jitka; Lucanova, Magdalena; Moravcová, Lenka; Nishino, Misako; Sadlo, Jiri; Suda, Jan; Tichy, Lubomir; Kühn, Ingolf

    2015-03-01

    The factors that promote invasive behavior in introduced plant species occur across many scales of biological and ecological organization. Factors that act at relatively small scales, for example, the evolution of biological traits associated with invasiveness, scale up to shape species distributions among different climates and habitats, as well as other characteristics linked to invasion, such as attractiveness for cultivation (and by extension propagule pressure). To identify drivers of invasion it is therefore necessary to disentangle the contribution of multiple factors that are interdependent. To this end, we formulated a conceptual model describing the process of invasion of central European species into North America based on a sequence of "drivers." We then used confirmatory path analysis to test whether the conceptual model is supported by a statistical model inferred from a comprehensive database containing 466 species. The path analysis revealed that naturalization of central European plants in North America, in terms of the number of North American regions invaded, most strongly depends on residence time in the invaded range and the number of habitats occupied by species in their native range. In addition to the confirmatory path analysis, we identified the effects of various biological traits on several important drivers of the conceptualized invasion process. The data supported a model that included indirect effects of biological traits on invasion via their effect on the number of native range habitats occupied and cultivation in the native range. For example, persistent seed banks and longer flowering periods are positively correlated with number of native habitats, while a stress-tolerant life strategy is negatively correlated with native range cultivation. However, the importance of the biological traits is nearly an order of magnitude less than that of the larger scale drivers and highly dependent on the invasion stage (traits were associated

  10. What regulates crab predation on mangrove propagules?

    OpenAIRE

    Van Nedervelde, F.; S.Cannicci; Koedam, N.; Bosire, J.; F. Dahdouh-Guebas

    2015-01-01

    Crabs play a major role in some ecosystems. To increase our knowledge about the factors that influence crab predation on propagules in mangrove forests, we performed experiments in Gazi Bay, Kenya in July 2009. We tested whether: (1) crab density influences propagule predation rate; (2) crab size influences food competition and predation rate; (3) crabs depredate at different rates according to propagule and canopy cover species; (4) vegetation density is correlated with crab density; (5) foo...

  11. Temporal Genetic Variance and Propagule-Driven Genetic Structure Characterize Naturalized Rainbow Trout (Oncorhynchus mykiss) from a Patagonian Lake Impacted by Trout Farming.

    Science.gov (United States)

    Benavente, Javiera N; Seeb, Lisa W; Seeb, James E; Arismendi, Ivan; Hernández, Cristián E; Gajardo, Gonzalo; Galleguillos, Ricardo; Cádiz, Maria I; Musleh, Selim S; Gomez-Uchida, Daniel

    2015-01-01

    Knowledge about the genetic underpinnings of invasions-a theme addressed by invasion genetics as a discipline-is still scarce amid well documented ecological impacts of non-native species on ecosystems of Patagonia in South America. One of the most invasive species in Patagonia's freshwater systems and elsewhere is rainbow trout (Oncorhynchus mykiss). This species was introduced to Chile during the early twentieth century for stocking and promoting recreational fishing; during the late twentieth century was reintroduced for farming purposes and is now naturalized. We used population- and individual-based inference from single nucleotide polymorphisms (SNPs) to illuminate three objectives related to the establishment and naturalization of Rainbow Trout in Lake Llanquihue. This lake has been intensively used for trout farming during the last three decades. Our results emanate from samples collected from five inlet streams over two seasons, winter and spring. First, we found that significant intra- population (temporal) genetic variance was greater than inter-population (spatial) genetic variance, downplaying the importance of spatial divergence during the process of naturalization. Allele frequency differences between cohorts, consistent with variation in fish length between spring and winter collections, might explain temporal genetic differences. Second, individual-based Bayesian clustering suggested that genetic structure within Lake Llanquihue was largely driven by putative farm propagules found at one single stream during spring, but not in winter. This suggests that farm broodstock might migrate upstream to breed during spring at that particular stream. It is unclear whether interbreeding has occurred between "pure" naturalized and farm trout in this and other streams. Third, estimates of the annual number of breeders (Nb) were below 73 in half of the collections, suggestive of genetically small and recently founded populations that might experience substantial

  12. Temporal Genetic Variance and Propagule-Driven Genetic Structure Characterize Naturalized Rainbow Trout (Oncorhynchus mykiss) from a Patagonian Lake Impacted by Trout Farming

    Science.gov (United States)

    Seeb, Lisa W.; Seeb, James E.; Arismendi, Ivan; Hernández, Cristián E.; Gajardo, Gonzalo; Galleguillos, Ricardo; Cádiz, Maria I.; Musleh, Selim S.

    2015-01-01

    Knowledge about the genetic underpinnings of invasions—a theme addressed by invasion genetics as a discipline—is still scarce amid well documented ecological impacts of non-native species on ecosystems of Patagonia in South America. One of the most invasive species in Patagonia’s freshwater systems and elsewhere is rainbow trout (Oncorhynchus mykiss). This species was introduced to Chile during the early twentieth century for stocking and promoting recreational fishing; during the late twentieth century was reintroduced for farming purposes and is now naturalized. We used population- and individual-based inference from single nucleotide polymorphisms (SNPs) to illuminate three objectives related to the establishment and naturalization of Rainbow Trout in Lake Llanquihue. This lake has been intensively used for trout farming during the last three decades. Our results emanate from samples collected from five inlet streams over two seasons, winter and spring. First, we found that significant intra- population (temporal) genetic variance was greater than inter-population (spatial) genetic variance, downplaying the importance of spatial divergence during the process of naturalization. Allele frequency differences between cohorts, consistent with variation in fish length between spring and winter collections, might explain temporal genetic differences. Second, individual-based Bayesian clustering suggested that genetic structure within Lake Llanquihue was largely driven by putative farm propagules found at one single stream during spring, but not in winter. This suggests that farm broodstock might migrate upstream to breed during spring at that particular stream. It is unclear whether interbreeding has occurred between “pure” naturalized and farm trout in this and other streams. Third, estimates of the annual number of breeders (Nb) were below 73 in half of the collections, suggestive of genetically small and recently founded populations that might experience

  13. What regulates crab predation on mangrove propagules?

    Science.gov (United States)

    Van Nedervelde, Fleur; Cannicci, Stefano; Koedam, Nico; Bosire, Jared; Dahdouh-Guebas, Farid

    2015-02-01

    Crabs play a major role in some ecosystems. To increase our knowledge about the factors that influence crab predation on propagules in mangrove forests, we performed experiments in Gazi Bay, Kenya in July 2009. We tested whether: (1) crab density influences propagule predation rate; (2) crab size influences food competition and predation rate; (3) crabs depredate at different rates according to propagule and canopy cover species; (4) vegetation density is correlated with crab density; (5) food preferences of herbivorous crabs are determined by size, shape and nutritional value. We found that (1) propagule predation rate was positively correlated to crab density. (2) Crab competitive abilities were unrelated to their size. (3) Avicennia marina propagules were consumed more quickly than Ceriops tagal except under C. tagal canopies. (4) Crab density was negatively correlated with the density of A. marina trees and pneumatophores. (5) Crabs prefer small items with a lower C:N ratio. Vegetation density influences crab density, and crab density affects propagule availability and hence vegetation recruitment rate. Consequently, the mutual relationships between vegetation and crab populations could be important for forest restoration success and management.

  14. Differences in the composition of arbuscular mycorrhizal fungal communities promoted by different propagule forms from a Mediterranean shrubland.

    Science.gov (United States)

    Varela-Cervero, Sara; López-García, Álvaro; Barea, José Miguel; Azcón-Aguilar, Concepción

    2016-07-01

    As it is well known, arbuscular mycorrhizal (AM) colonization can be initiated from the following three types of fungal propagules: spores, extraradical mycelium (ERM), and mycorrhizal root fragments harboring intraradical fungal structures. It has been shown that biomass allocation of AM fungi (AMF) among these three propagule types varies between fungal taxa, as also differs the ability of the different AMF propagule fractions to initiate new colonizations. In this study, the composition of the AMF community in the roots of rosemary (Rosmarinus officinalis L., a characteristic Mediterranean shrub), inoculated with the three different propagule types, was analyzed. Accordingly, cuttings from this species were inoculated with either AMF spores, ERM, or colonized roots extracted from a natural soil. The AMF diversity within the rosemary roots was characterized using terminal restriction fragment length polymorphism (T-RFLP) of the small subunit (SSU) rDNA region. The AMF community established in the rosemary plants was significantly different according to the type of propagule used as inoculum. AMF taxa differed in their ability to initiate new colonizations from each propagule type. Results suggest different colonization strategies for the different AMF families involved, Glomeraceae and Claroideoglomeraceae colonizing mainly from colonized roots whereas Pacisporaceae and Diversisporaceae from spores and ERM. This supports that AMF taxa show contrasting life-history strategies in terms of their ability to initiate new colonizations from the different propagule types. Further research to fully understand the colonization and dispersal abilities of AMF is essential for their rational use in ecosystem restoration programs. PMID:26883142

  15. Arbuscular mycorrhizal propagules in soils from a tropical forest and an abandoned cornfield in Quintana Roo, Mexico: visual comparison of most-probable-number estimates.

    Science.gov (United States)

    Ramos-Zapata, José A; Guadarrama, Patricia; Navarro-Alberto, Jorge; Orellana, Roger

    2011-02-01

    The present study was aimed at comparing the number of arbuscular mycorrhizal fungi (AMF) propagules found in soil from a mature tropical forest and that found in an abandoned cornfield in Noh-Bec Quintana Roo, Mexico, during three seasons. Agricultural practices can dramatically reduce the availability and viability of AMF propagules, and in this way delay the regeneration of tropical forests in abandoned agricultural areas. In addition, rainfall seasonality, which characterizes deciduous tropical forests, may strongly influence AMF propagules density. To compare AMF propagule numbers between sites and seasons (summer rainy, winter rainy and dry season), a "most probable number" (MPN) bioassay was conducted under greenhouse conditions employing Sorgum vulgare L. as host plant. Results showed an average value of 3.5 ± 0.41 propagules in 50 ml of soil for the mature forest while the abandoned cornfield had 15.4 ± 5.03 propagules in 50 ml of soil. Likelihood analysis showed no statistical differences in MPN of propagules between seasons within each site, or between sites, except for the summer rainy season for which soil from the abandoned cornfield had eight times as many propagules compared to soil from the mature forest site for this season. Propagules of arbuscular mycorrhizal fungi remained viable throughout the sampling seasons at both sites. Abandoned areas resulting from traditional slash and burn agriculture practices involving maize did not show a lower number of AMF propagules, which should allow the establishment of mycotrophic plants thus maintaining the AMF inoculum potential in these soils. PMID:20714755

  16. Mangrove propagule size and oil contamination effects: Does size matter?

    Science.gov (United States)

    Naidoo, Gonasageran

    2016-09-15

    Three mangroves species with differential propagule size, Avicennia marina (2.5±0.3cm), Bruguiera gymnorrhiza (16±2cm) and Rhizophora mucronata (36±3cm), were subjected to oil contamination. In a series of glasshouse and field experiments, the sediment, propagules, leaves and stems were oiled and growth monitored. Oiling of the propagules, leaves, internodes or sediment reduced plant height, leaf number, leaf chlorophyll content index and induced growth abnormalities, leaf abscission and mortality, with effects being greatest in A. marina, intermediate in R. mucronata and least in B. gymnorrhiza. The results suggest that the greater susceptibility of A. marina to oil is due to early shedding of the protective pericarp and rapid root and shoot development after detachment from the parent tree and not to propagule size. After seedling emergence, micromorphological factors such as presence of trichomes, salt glands and thickness of protective barriers influence oil tolerance. PMID:27342901

  17. The role of wind in hydrochorous mangrove propagule dispersal

    Directory of Open Access Journals (Sweden)

    T. Van der Stocken

    2013-01-01

    Full Text Available Although wind has been recognized to be an important factor in the dispersal of hydrochorous mangrove propagules, and hence in the quantification of (metapopulation dynamics, the species-specific sensitivity to wind effects have not been studied. We combined observations from a controlled experiment (flume tank and in situ experiments to understand wind and water current contributions to dispersal potential as well as to estimate real dispersal ranges due to immediate response to tidal currents (two outgoing tides. This was done for 5 species with propagules differing in morphological and buoyancy properties (i.e. Rhizophora mucronata, Ceriops tagal, Heritiera littoralis and Xylocarpus granatum. The flume experiments revealed that the influence of wind depends on the density of a propagule (and hence its buoyancy characteristics and that typical morphological characteristics of the dispersal unit are additionally important. H. littoralis propagules were influenced most, because on the one hand their low density (613.58 g l−1; n=10 enables them to float on top of the water surface, and on the other hand their "sailboat-like" structure provides a relatively large surface area. The X. granatum fruits appeared to be the least influenced by ambient wind conditions, explained by the smooth surface and spherical shape of which, because of the fruit's high density (890.05 g l−1; n=1, only a small part sticks above the water surface. Although the seeds of X. granatum are of a similar size class than H. littoralis propagules, they are (like the X. granatum fruits largely submerged due to their high density (870.66 g l−1; n=8, hence catching less wind than H. littoralis propagules. The influence of wind on the dispersal of the horizontally floating C. tagal and R. mucronata dispersal units was strong, comparable to that of

  18. The role of wind in hydrochorous mangrove propagule dispersal

    Directory of Open Access Journals (Sweden)

    T. Van der Stocken

    2013-06-01

    Full Text Available Although wind has been recognized to be an important factor in the dispersal of hydrochorous mangrove propagules, and hence in the quantification of (metapopulation dynamics, the species-specific sensitivity to wind effects has not been studied. We combined observations from a controlled experiment (flume tank and in situ experiments to understand wind and water current contributions to dispersal potential as well as to estimate real dispersal ranges due to immediate response to tidal currents (two outgoing tides. This was done for 4 species with propagules differing in morphological and buoyancy properties (i.e. Rhizophora mucronata, Ceriops tagal, Heritiera littoralis and Xylocarpus granatum. The flume experiments revealed that the influence of wind depends on the density of a propagule (and hence its buoyancy characteristics and that typical morphological characteristics of the dispersal unit are additionally important. H. littoralis propagules were influenced most, because on the one hand their low density (613.58 g L−1; n =10 enables them to float on top of the water surface, and on the other hand their "sailboat-like" structure provides a relatively large surface area. The X. granatum fruits appeared to be the least influenced by ambient wind conditions, explained by the smooth surface and spherical shape of which, because of the fruit's high density (890.05 g L−1; n = 1, only a small part sticks above the water surface. Although the seeds of X. granatum are of a similar size class than H. littoralis propagules, they are (like the X. granatum fruits largely submerged due to their high density (870.66 g L−1; n = 8, hence catching less wind than H. littoralis propagules. The influence of wind on the dispersal of the horizontally floating C. tagal and R. mucronata dispersal units was strong, comparable to that of H. littoralis propagules. A differential effect of wind was found within elongated propagules, which directly follows from

  19. Release of Streptomyces albus propagules from contaminated surfaces

    International Nuclear Information System (INIS)

    The release of Streptomyces albus propagules from contaminated agar an ceiling tile surfaces was studied under controlled environmental condition in a newly developed aerosolization chamber. The experiments revealed tha both spores and cell fragments can be simultaneously released from the colonized surface by relatively gentle air currents of 0.3 m s-1. A 100x increase of the air velocity can result in a 50-fold increase in the number of released propagules. The aerosolization rate depends strongly on the typ and roughness of the contaminated surface. Up to 90% of available actinomycete propagules can become airborne during the first 10 min of th release process. Application of vibration to the surface did not reveal an influence on the aerosolization process of S. albus propagules under th tested conditions. This study has shown that propagules in the fine particle size range can be released in large amounts from contaminated surfaces Measurement of the number of S. albus fragments in the vicinity of contaminated area, as an alternative to conventional air or surface sampling appears to be a promising approach for quantitative exposure assessment

  20. Modelling drivers of mangrove propagule dispersal and restoration of abandoned shrimp farms

    Directory of Open Access Journals (Sweden)

    D. Di Nitto

    2013-07-01

    Full Text Available Propagule dispersal of four mangrove species Rhizophora mucronata, R. apiculata, Ceriops tagal and Avicennia officinalis in the Pambala–Chilaw Lagoon Complex (Sri Lanka was studied by combining a hydrodynamic model with species-specific knowledge on propagule dispersal behaviour. Propagule transport was simulated using a finite-volume advection-diffusion model to investigate the effect of dispersal vectors (tidal flow, freshwater discharge and wind, trapping agents (retention by vegetation and seed characteristics (buoyancy on propagule dispersal patterns. Sensitivity analysis showed that smaller propagules, like the oval-shaped propagules of Avicennia officinalis, dispersed over larger distances and were most sensitive to changing values of retention by mangrove vegetation compared to larger, torpedo-shaped propagules of Rhizophora spp. and C. tagal. Directional propagule dispersal in this semi-enclosed lagoon with a small tidal range was strongly concentrated towards the edges of the lagoon and channels. Short distance dispersal appeared to be the main dispersal strategy for all four studied species, with most of the propagules being retained within the vegetation. Only a small proportion (max. 5% of propagules left the lagoon through a channel connecting the lagoon with the open sea. Wind significantly influenced dispersal distance and direction once propagules entered the lagoon or adjacent channels. Implications of these findings for mangrove restoration were tested by simulating partial removal in the model of dikes around abandoned shrimp ponds to restore tidal hydrology and facilitate natural recolonisation by mangroves. The specific location of dike removal, (with respect to the vicinity of mangroves and independently suitable hydrodynamic flows, was found to significantly affect the resultant quantities and species of inflowing propagules and hence the potential effectiveness of natural regeneration. These results demonstrate the

  1. Modelling drivers of mangrove propagule dispersal and restoration of abandoned shrimp farms

    Science.gov (United States)

    Di Nitto, D.; Erftemeijer, P. L. A.; van Beek, J. K. L.; Dahdouh-Guebas, F.; Higazi, L.; Quisthoudt, K.; Jayatissa, L. P.; Koedam, N.

    2013-07-01

    Propagule dispersal of four mangrove species Rhizophora mucronata, R. apiculata, Ceriops tagal and Avicennia officinalis in the Pambala-Chilaw Lagoon Complex (Sri Lanka) was studied by combining a hydrodynamic model with species-specific knowledge on propagule dispersal behaviour. Propagule transport was simulated using a finite-volume advection-diffusion model to investigate the effect of dispersal vectors (tidal flow, freshwater discharge and wind), trapping agents (retention by vegetation) and seed characteristics (buoyancy) on propagule dispersal patterns. Sensitivity analysis showed that smaller propagules, like the oval-shaped propagules of Avicennia officinalis, dispersed over larger distances and were most sensitive to changing values of retention by mangrove vegetation compared to larger, torpedo-shaped propagules of Rhizophora spp. and C. tagal. Directional propagule dispersal in this semi-enclosed lagoon with a small tidal range was strongly concentrated towards the edges of the lagoon and channels. Short distance dispersal appeared to be the main dispersal strategy for all four studied species, with most of the propagules being retained within the vegetation. Only a small proportion (max. 5%) of propagules left the lagoon through a channel connecting the lagoon with the open sea. Wind significantly influenced dispersal distance and direction once propagules entered the lagoon or adjacent channels. Implications of these findings for mangrove restoration were tested by simulating partial removal in the model of dikes around abandoned shrimp ponds to restore tidal hydrology and facilitate natural recolonisation by mangroves. The specific location of dike removal, (with respect to the vicinity of mangroves and independently suitable hydrodynamic flows), was found to significantly affect the resultant quantities and species of inflowing propagules and hence the potential effectiveness of natural regeneration. These results demonstrate the value of propagule

  2. Modelling drivers of mangrove propagule dispersal and restoration of abandoned shrimp farms

    Directory of Open Access Journals (Sweden)

    D. Di Nitto

    2013-01-01

    Full Text Available Propagule dispersal of four mangrove species Rhizophora mucronata, R. apiculata, Ceriops tagal and Avicennia officinalis in the Pambala-Chilaw Lagoon Complex (Sri Lanka was studied by combining a hydrodynamic model with species-specific knowledge on propagule dispersal behaviour. Propagule transport was simulated using a finite-volume advection-diffusion model to investigate the effect of dispersal vectors (tidal flow, freshwater discharge and wind, trapping agents (retention by vegetation and seed characteristics (buoyancy on propagule dispersal patterns. Sensitivity analysis showed that smaller propagules, like the oval-shaped propagules of Avicennia officinalis, dispersed over larger distances and were most sensitive to changing values of retention by mangrove vegetation compared to larger, torpedo-shaped propagules of Rhizophora spp. and C. tagal. Directional propagule dispersal in this semi-enclosed lagoon with a small tidal range was strongly concentrated towards the edges of the lagoon and channels. Short distance dispersal appeared to be the main dispersal strategy for all four studied species, with most of the propagules being retained within the vegetation. Only a small proportion (max. 5% of propagules left the lagoon through a channel connecting the lagoon with the open sea. Wind significantly influenced dispersal distance and direction once propagules entered the lagoon or adjacent channels. Implications of these findings for mangrove restoration were tested by simulating partial removal in the model of dikes around abandoned shrimp ponds to restore tidal hydrology and facilitate natural recolonisation by mangroves. The specific location of dike removal, (with respect to the vicinity of mangroves and independently suitable hydrodynamic flows, was found to significantly affect the resultant quantities and species of inflowing of propagules and hence the potential effectiveness of natural

  3. Impact of wildfire return interval on the ectomycorrhizal resistant propagules communities of a Mediterranean open forest.

    Science.gov (United States)

    Buscardo, Erika; Rodríguez-Echeverría, Susana; Martín, María P; De Angelis, Paolo; Pereira, João Santos; Freitas, Helena

    2010-08-01

    Ectomycorrhizal (ECM) fungi, in particular their spores and other resistant propagules, play an important role in secondary succession processes that facilitate regeneration after disturbance events. In this study, the effects of high and low wildfire frequencies (respectively short and long fire return intervals) on the resistant propagules communities (RPCs) of a Mediterranean open pine forest were compared. Soil samples were collected in four mountain sites with different fire return intervals and used to test ectomycorrhiza development in two hosts, Pinus pinaster and Quercus suber. RPCs were characterized by direct sequencing of fungal internal transcribed spacer (ITS) regions from individual ECM root tips. Eighteen ECM species were detected in the bioassay. The most frequently found fungi were Cenococcum geophilum, Inocybe jacobi, Thelephora terrestris, Tomentella ellisii on both hosts and Rhizopogon luteolus and R. roseolus on maritime pine. A short fire return interval reduced the species richness of the ECM community found on Q. suber, promoted species like R. roseolus and reduced the abundance of other species (e.g. R. luteolus). The abundance of I. jacobi was positively affected by long fire return interval, but decreased significantly with recurrent fires. These results indicate that changes in fire frequency can alter the structure, composition and diversity of ECM communities, which could compromise the resilience of the ecosystem in highly disturbed areas. PMID:20943174

  4. Saltmarsh boundary modulates dispersal of mangrove propagules: implications for mangrove migration with sea-level rise.

    Science.gov (United States)

    Peterson, Jennifer M; Bell, Susan S

    2015-01-01

    Few studies have empirically examined the suite of mechanisms that underlie the distributional shifts displayed by organisms in response to changing climatic condition. Mangrove forests are expected to move inland as sea-level rises, encroaching on saltmarsh plants inhabiting higher elevations. Mangrove propagules are transported by tidal waters and propagule dispersal is likely modified upon encountering the mangrove-saltmarsh ecotone, the implications of which are poorly known. Here, using an experimental approach, we record landward and seaward dispersal and subsequent establishment of mangrove propagules that encounter biotic boundaries composed of two types of saltmarsh taxa: succulents and grasses. Our findings revealed that propagules emplaced within saltmarsh vegetation immediately landward of the extant mangrove fringe boundary frequently dispersed in the seaward direction. However, propagules moved seaward less frequently and over shorter distances upon encountering boundaries composed of saltmarsh grasses versus succulents. We uniquely confirmed that the small subset of propagules dispersing landward displayed proportionately higher establishment success than those transported seaward. Although impacts of ecotones on plant dispersal have rarely been investigated in situ, our experimental results indicate that the interplay between tidal transport and physical attributes of saltmarsh vegetation influence boundary permeability to propagules, thereby directing the initial phase of shifting mangrove distributions. The incorporation of tidal inundation information and detailed data on landscape features, such as the structure of saltmarsh vegetation at mangrove boundaries, should improve the accuracy of models that are being developed to forecast mangrove distributional shifts in response to sea-level rise. PMID:25760867

  5. Saltmarsh boundary modulates dispersal of mangrove propagules: implications for mangrove migration with sea-level rise.

    Directory of Open Access Journals (Sweden)

    Jennifer M Peterson

    Full Text Available Few studies have empirically examined the suite of mechanisms that underlie the distributional shifts displayed by organisms in response to changing climatic condition. Mangrove forests are expected to move inland as sea-level rises, encroaching on saltmarsh plants inhabiting higher elevations. Mangrove propagules are transported by tidal waters and propagule dispersal is likely modified upon encountering the mangrove-saltmarsh ecotone, the implications of which are poorly known. Here, using an experimental approach, we record landward and seaward dispersal and subsequent establishment of mangrove propagules that encounter biotic boundaries composed of two types of saltmarsh taxa: succulents and grasses. Our findings revealed that propagules emplaced within saltmarsh vegetation immediately landward of the extant mangrove fringe boundary frequently dispersed in the seaward direction. However, propagules moved seaward less frequently and over shorter distances upon encountering boundaries composed of saltmarsh grasses versus succulents. We uniquely confirmed that the small subset of propagules dispersing landward displayed proportionately higher establishment success than those transported seaward. Although impacts of ecotones on plant dispersal have rarely been investigated in situ, our experimental results indicate that the interplay between tidal transport and physical attributes of saltmarsh vegetation influence boundary permeability to propagules, thereby directing the initial phase of shifting mangrove distributions. The incorporation of tidal inundation information and detailed data on landscape features, such as the structure of saltmarsh vegetation at mangrove boundaries, should improve the accuracy of models that are being developed to forecast mangrove distributional shifts in response to sea-level rise.

  6. Characterizing Acoustic Sources in Pressure Vessels

    Institute of Scientific and Technical Information of China (English)

    李路明; 郑鹏; 刘时风; 施克仁

    2002-01-01

    The "dream" of acoustic emission (AE) testing is to get the acoustic source characteristics from AE signals, especially when evaluating aging pressure vessels. In this paper, the wavelet transform was used to analyze different AE signals from cracks (surface and inner), pencil-lead-breakage and leakage. These acoustic sources were applied on an actual pressure vessel. While the vessel experienced hydraulic pressure, their AE signals were acquired by a digital AE testing system with a wide frequency band transducer and a high speed A/D converter. Then, the digital signals were analyzed using the wavelet transform method. Correlation coefficients of the transformed data show that the different acoustic sources can be easily identified.

  7. Saltmarsh Boundary Modulates Dispersal of Mangrove Propagules: Implications for Mangrove Migration with Sea-Level Rise

    OpenAIRE

    Peterson, Jennifer M; Bell, Susan S.

    2015-01-01

    Few studies have empirically examined the suite of mechanisms that underlie the distributional shifts displayed by organisms in response to changing climatic condition. Mangrove forests are expected to move inland as sea-level rises, encroaching on saltmarsh plants inhabiting higher elevations. Mangrove propagules are transported by tidal waters and propagule dispersal is likely modified upon encountering the mangrove-saltmarsh ecotone, the implications of which are poorly known. Here, using ...

  8. Impact of wildfire frequency on the ectomycorrhizal resitant propagules communities of a Mediterranean open forest

    OpenAIRE

    Buscardo, Erika; Rodríguez-Echeverría, Susana; Martín, María Paz; De Angelis, Paolo; Pereira, João Santos; Freitas, Helena

    2010-01-01

    Ectomycorrhizal (ECM) fungi, in particular their spores and other resistant propagules, play an important role in secondary succession processes that facilitate regeneration after disturbance events. In this study, the effects of high and low wildfire frequencies (respectively short and long fire return intervals) on the resistant propagules communities (RPCs) of a Mediterranean open pine forest were compared. Soil samples were collected in four mountain sites with different fire return inter...

  9. Soil propagule banks of ectomycorrhizal fungi along forest development stages after mining.

    Science.gov (United States)

    Huang, Jian; Nara, Kazuhide; Zong, Kun; Lian, Chunlan

    2015-05-01

    Ectomycorrhizal fungal (EMF) propagules play an important role in seedling establishment following disturbance. However, little is known about how the EMF propagule community changes with forest development. In this study, EMF propagules were examined using seedling bioassays in rhizosphere soils collected from a recently closed Pb-Zn tailing (Taolin Pb-Zn tailing (TLT)), a Cu tailing (Dexing Cu No. 2 tailing (DXT)) that had undergone 21 years of restoration, and a mature Masson pine (Pinus massoniana) forest (DXC) outside the Cu mining areas. The corresponding EMF communities colonizing Masson pine at each site were also investigated for comparison. After 8 months of running bioassays, ectomycorrhizal colonization was poor for seedlings grown in TLT (9.0 % ± 14.9 %) and DXT soils (22.4 % ± 17.7 %), while DXC seedlings were well colonized (47.5 % ± 24.9 %). Internal transcribed spacer sequencing revealed that EMF species richness increased with forest development in both the propagule bank (TLT, 6; DXT, 7; DXC, 12) and in the field (TLT, 8; DXT, 14; DXC, 26), though richness was lower in propagule banks. Several lineages, such as Cenococcum, Rhizopogon, Inocybe, Suillus, and Atheliaceae, were frequently encountered in propagule communities, but species assemblages were different among the three sites. Canonical correspondence analysis revealed that several soil parameters, i.e., N, EC, Cu, Pb, Zn, etc., were responsible for the distribution of EMF in the field and bioassay seedlings. The highest overlap in EMF species composition between the propagule bank and the field community was observed at the recently closed tailing (Morisita-Horn similarity = 0.71 for TLT), whereas the lowest overlap occurred at the mature forest (0.26 for DXC). These results indicate that EMF propagules in soil are less frequent and diverse in early primary succession and become more frequent and diverse along forest development, due mainly to the accumulation of

  10. Burial Duration and Frequency Influences Resilience of Differing Propagule Types in a Subtidal Seagrass, Posidonia australis.

    Science.gov (United States)

    Campbell, Marnie L

    2016-01-01

    Sedimentation that leads to periodic, and often prolonged, burial events is becoming more common on the world's coastlines as human populations expand and create urbanised marine environments. Different seagrass species react differently to sediment burial but many species in the southern hemisphere are yet to be examined. How seagrasses react to burial has restoration implications. There is a need to critically assess seagrass transplant propagule responses to periodic (pulse) and prolonged (press) burial events before selecting the most appropriate species, transplant propagule, and transplant site. In my study, mesocosm experiments, coupled with field measurements were used to assess how sexual (seedlings) and vegetative (sprigs) propagules of Posidonia australis responded to pulse and press burial events. Seedlings were highly susceptible to burial (both pulse and press), with no survival at the end of the experimental period. In contrast, rhizome growth in vegetative propagules was stimulated by pulse burial, although press burial events resulted in mortality. The implication for Posidonia australis restoration efforts in areas where burial is periodic, was that vegetative propagules are optimal transplant units, in comparison to seedlings. Press burial however, renders a transplant site sub-optimal for both seedling and sprig transplants. PMID:27526020

  11. Characterization of pressure distribution in penetrating traumatic brain injuries.

    Science.gov (United States)

    Davidsson, Johan; Risling, Mårten

    2015-01-01

    Severe impacts to the head commonly lead to localized brain damage. Such impacts may also give rise to temporary pressure changes that produce secondary injuries in brain volumes distal to the impact site. Monitoring pressure changes in a clinical setting is difficult; detailed studies into the effect of pressure changes in the brain call for the development and use of animal models. The aim of this study is to characterize the pressure distribution in an animal model of penetrating traumatic brain injuries (pTBI). This data may be used to validate mathematical models of the animal model and to facilitate correlation studies between pressure changes and pathology. Pressure changes were measured in rat brains while subjected to pTBI for a variety of different probe velocities and shapes; pointy, blunt, and flat. Experiments on ballistic gel samples were carried out to study the formation of any temporary cavities. In addition, pressure recordings from the gel experiments were compared to values recorded in the animal experiments. The pTBI generated short lasting pressure changes in the brain tissue; the pressure in the contralateral ventricle (CLV) increased to 8 bar followed by a drop to 0.4 bar when applying flat probes. The pressure changes in the periphery of the probe, in the Cisterna Magna, and the spinal canal, were significantly less than those recorded in the CLV or the vicinity of the skull base. High-speed videos of the gel samples revealed the formation of spherically shaped cavities when flat and spherical probes were applied. Pressure changes in the gel were similar to those recorded in the animals, although amplitudes were lower in the gel samples. We concluded cavity expansion rate rather than cavity size correlated with pressure changes in the gel or brain secondary to probe impact. The new data can serve as validation data for finite element models of the trauma model and the animal and to correlate physical measurements with secondary injuries

  12. Bulk characterization of pharmaceutical powders by low-pressure compression

    DEFF Research Database (Denmark)

    Sørensen, A.H.; Sonnergaard, Jørn; Hovgaard, L.

    2005-01-01

    Low-pressure compression of pharmaceutical powders using small amounts of sample (50 mg) was evaluated as an alternative to traditional bulk powder characterization by tapping volumetry. Material parameters were extrapolated directly from the compression data and by fitting with the Walker, the...... Kawakita, and the Log-Exp compression models. The compression-derived material parameters were compared to the poured and tapped density and the Compressibility Index determined by tapping. The repeatability of the compression-derived parameters was generally high, supporting their potential for...... characterization purposes. Significant correlation was demonstrated between several of the compression and tapping-derived parameters. The discriminative power of the low-pressure compression test was discussed using the compressed density at 0.2 MPa, correlated with the tapped density, and the relative Walker...

  13. Aliens in Antarctica: Assessing transfer of plant propagules by human visitors to reduce invasion risk

    NARCIS (Netherlands)

    Huiskes, A.H.L.; Gremmen, N.J.M.; Bergstrom, D.M.; Frenot, Y.; Hughes, K.A.; Imura, S.; Kiefer, K.; Lebouvier, M.; Lee, J.E.; Tsujimoto, M.; Ware, C.; Van de Vijver, B.; Chown, S.L.

    2014-01-01

    Despite considerable research on biological invasions, key areas remain poorly explored, especially ways to reduce unintentional propagule transfer. The Antarctic represents a microcosm of the situation, with the numbers of established non-native species growing. Information to help reduce potential

  14. Pressure-dependent terahertz optical characterization of heptafluoropropane

    International Nuclear Information System (INIS)

    Heptafluoropropane (HFP), as the best alternative to halon fire-suppression agents, is now a widely used fire extinguishing agent. The current studies of HFP, concentrating on the extinguishing mechanisms of flames and decomposition products, in general deal with the destructive and high temperature cases. In this paper, terahertz time-domain spectra are used to characterize HFP at different pressures. Optical parameters of HFP, such as absorption coefficient, refractive index, and relative permittivity, and their relationship with concentration of samples, are discussed. The absorption peak of HFP at 0.3 THz depends strongly on the applied pressure, and the corresponding parameters increase almost linearly with increasing HFP concentration. The present study lays a foundation for future extensive applications. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  15. Characterization of an ultra-low vapor pressure ferrofluid

    International Nuclear Information System (INIS)

    A Perfluoropolyether (PFPE) based ferrofluid was characterized. The finished ferrofluid had the magnetization and viscosity values of 450 G and 9625 cP respectively at 27 deg. C. It was found to have low volatility, long life, and stability under combined high temperature and magnetic field. These properties qualify the material for use in bakeable magnetic fluid seals for clean UHV environments. A novel method was used to measure the vapor pressure of the ferrofluid as a function of time and temperature. The room temperature vapor pressure of the subject ferrofluid was measured as 3x10-10 mmHg after 1 h of exposure to high vacuum. It decayed to 3x10-11 mmHg after 5 h and 3x10-12 mmHg after 450 h

  16. Characterization of a cryogenically cooled high-pressure gas jet

    International Nuclear Information System (INIS)

    We have developed and carried out a detailed characterization of a cryogenically cooled(80 K)high-pressure(50 x 105Pa) solenoid driven pulsed valve that has been used to produce dense jets of deuterium atomic clusters for interaction studies with high intensity laser. Rayleigh scattering was employed to investigate the scaling law between cluster size and upstream gas pressure, which was shown to be of the form Nc∝P02.89. Cluster size gets to its peak Nc≅2630 at 80 K, 48 x 105 Pa. We also studied the cluster formation process, portrayed a characteristic curve which revealed cluster size temporal evolution. Our results are important for analyzing the cluster interaction with intense laser, and are expected to provide guidelines to choose proper fire time. (authors)

  17. A review of the genus Bulbothrix Hale: the species with medullary salazinic acid lacking vegetative propagules

    Directory of Open Access Journals (Sweden)

    Michel Benatti

    2012-10-01

    Full Text Available Descriptions are presented for the seven known Bulbothrix (Parmeliaceae, Lichenized Fungi species with salazinic acid in the medulla and without vegetative propagules. Bulbothrix continua, previously considered as a synonym of B. hypocraea, is recognized as independent species. The current delimitations are confirmed for B. enormis, B. hypocraea, B. meizospora, B. linteolocarpa, B. sensibilis, and B. setschwanensis. New characteriscs and range extensions are provided.

  18. Propagules of arbuscular mycorrhizal fungi in a secondary dry forest of Oaxaca, Mexico.

    Science.gov (United States)

    Guadarrama, Patricia; Castillo-Argüero, Silvia; Ramos-Zapata, José A; Camargo-Ricalde, Sara L; Alvarez-Sánchez, Javier

    2008-03-01

    Plant cover loss due to changes in land use promotes a decrease in spore diversity of arbuscular mycorrhizal fungi (AMF), viable mycelium and, therefore, in AMF colonization, this has an influence in community diversity and, as a consequence, in its recovery. To evaluate different AMF propagules, nine plots in a tropical dry forest with secondary vegetation were selected: 0, 1, 7, 10, 14, 18, 22, 25, and 27 years after abandonment in Nizanda, Oaxaca, Mexico. The secondary vegetation with different stages of development is a consequence of slash and burn agriculture, and posterior abandonment. Soil samples (six per plot) were collected and percentage of AMF field colonization, extrarradical mycelium, viable spore density, infectivity and most probable number (MPN) ofAMF propagules were quantified through a bioassay. Means for field colonization ranged between 40% and 70%, mean of total mycelium length was 15.7 +/- 1.88 mg(-1) dry soil, with significant differences between plots; however, more than 40% of extracted mycelium was not viable, between 60 and 456 spores in 100 g of dry soil were recorded, but more than 64% showed some kind of damage. Infectivity values fluctuated between 20% and 50%, while MPN showed a mean value of 85.42 +/- 44.17 propagules (100 g dry soil). We conclude that secondary communities generated by elimination of vegetation with agricultural purposes in a dry forest in Nizanda do not show elimination of propagules, probably as a consequence of the low input agriculture practices in this area, which may encourage natural regeneration. PMID:18624242

  19. Wind pollination and propagule formation in Rhizophora mangle L. (Rhizophoraceae): resource or pollination limitation?

    Science.gov (United States)

    Nadia, Tarcila L; Machado, Isabel C

    2014-03-01

    Rhizophora mangle is considered as a self-compatible mangrove, and is pollinated by wind and insects. However, there is no information about fruit production by autogamy and agamospermy and on the foraging behavior of its flower visitors. Hence, the present study analyzed the pollination and reproductive systems of R. mangle in a mangrove community in northern Pernambuco, Brazil. Floral morphology, sequence of anthesis, and behavior of flower visitors were described; the proportion of flowers that resulted in mature propagules was also recorded. Autogamy, agamospermy, and wind pollination tests were performed, and a new anemophily index is proposed. The flowers of R. mangle are hermaphrodite, protandric, and have high P/O rate. Flies were observed on flowers only during the male phase, probably feeding on mites that consume pollen. Rhizophora mangle is not agamospermic and its fruit production rate by spontaneous self-pollination is low (2.56%) compared to wind pollination (19.44%). The anemophily index was high 0.98, and thus it was considered as a good indicator. Only 13.79% of the flowers formed mature propagules. The early stages of fruit development are the most critical and susceptible to predation. Rhizophora mangle is, therefore, exclusively anemophilous in the study area and the propagule dispersal seems to be limited by herbivory. PMID:24804313

  20. Electrical characterization of atmospheric pressure dielectric barrier discharge in air

    International Nuclear Information System (INIS)

    This paper reports the electrical characterization of dielectric barrier discharge produced at atmospheric pressure using a high voltage power supply operating at 50Hz. The characteristics of the discharge have been studied under different values as such applied voltage and the electrode gap width. The results presented in this work can be helpful in understanding the influence of dielectric material on the nature of the discharge. An attempt has also been made to investigate the influence of ballast resistor on the magnitude of discharge current and also the density of micro-discharges. Our results indicated that with this power supply and electrode geometry, a relatively more homogenous discharge is observed for 3 mm spacing. (author)

  1. Naturalization of central European plants in North America: species traits, habitats, propagule pressure, residence time

    Czech Academy of Sciences Publication Activity Database

    Pyšek, Petr; Manceur, A. M.; Alba, Christina; McGregor, Kirsty; Pergl, Jan; Štajerová, Kateřina; Chytrý, M.; Danihelka, Jiří; Kartesz, J.; Klimešová, Jitka; Lučanová, Magdalena; Moravcová, Lenka; Nishino, M.; Sádlo, Jiří; Suda, Jan; Tichý, L.; Kühn, I.

    2015-01-01

    Roč. 96, č. 3 (2015), s. 762-774. ISSN 0012-9658 R&D Projects: GA ČR GB14-36079G; GA ČR(CZ) GA14-15414S; GA ČR(CZ) GAP504/11/1028; GA ČR(CZ) GAP505/11/1112 Grant ostatní: AV ČR(CZ) Praemium Academiae Institutional support: RVO:67985939 Keywords : invasions * naturalization * species traits Subject RIV: EH - Ecology, Behaviour Impact factor: 4.656, year: 2014

  2. Influence of the size of garlic propagules on radiosensitivity of clones

    International Nuclear Information System (INIS)

    The influence of the size of garlic propagules selected to be irradiated on the results of radiosensitivity was studied so as to determine the useful radiation doses for improvement. This was done using radio inhibition of the plant height index as criteria and the mahalanobis distance stadigrapher calculated among defined groups for the behaviour of cloves in reference to six radiation doses. Significative differences were found among dose-effect curves obtained when using big cloves and small cloves, in five garlic clones, as well as different behaviours of clone radiosensitivity when it was investigated using the two proposed variants

  3. Shock response of porous metals: characterization of pressure field

    International Nuclear Information System (INIS)

    Shock wave reaction on porous metals is numerically simulated. When the pressure threshold is low, the increasing rate of high-pressure area gives roughly the propagation velocity of the compressive waves in the porous material. and the wave front in the condensed pressure map is nearly a plane: with the increasing of pressure threshold. more low-pressure-spots appear in the high-pressure background, and neighboring spots may coalesce, consequently, the topology of the pressure Turing pattern may change. The deviation from linearity of the increasing rate of high-pressure area is a pronounced effect of porous material under shock. The stronger the initial shock, the more pronounced the porosity effects. When the initial yield of material becomes higher, the material shows more elastic behaviors and the less porous effects, compressive and tension waves propagate more quickly, and the porous material becomes less compressible. (authors)

  4. Comparative performance of two air samplers for monitoring airborne fungal propagules

    Directory of Open Access Journals (Sweden)

    L.G.F. Távora

    2003-05-01

    Full Text Available Many studies have attempted to evaluate the importance of airborne fungi in the development of invasive fungal infection, especially for immunocompromised hosts. Several kinds of instruments are available to quantitate fungal propagule levels in air. We compared the performance of the most frequently used air sampler, the Andersen sampler with six stages, with a portable one, the Reuter centrifugal sampler (RCS. A total of 84 samples were analyzed, 42 with each sampler. Twenty-eight different fungal genera were identified in samples analyzed with the Andersen instrument. In samples obtained with the RCS only seven different fungal genera were identified. The three most frequently isolated genera in samples analyzed with both devices were Penicillium, Aspergillus and Cladophialophora. In areas supplied with a high efficiency particulate air filter, fungal spore levels were usually lower when compared to areas without these filters. There was a significant correlation between total fungal propagule measurements taken with both devices on each sampling occasion (Pearson coefficient = 0.50. However, the Andersen device recovered a broader spectrum of fungi. We conclude that the RCS can be used for quantitative estimates of airborne microbiological concentrations. For qualitative studies, however, this device cannot be recommended.

  5. Novel fabric pressure sensors: design, fabrication, and characterization

    International Nuclear Information System (INIS)

    Soft and pliable pressure sensors are essential elements in wearable electronics which have wide applications in modern daily lives. This paper presents a family of fabric pressure sensors made by sandwiching a piece of resistive fabric strain sensing element between two tooth-structured layers of soft elastomers. The pressure sensors are capable of measuring pressure from 0 to 2000 kPa, covering the whole range of human–machine interactions. A pressure sensitivity of up to 2.98 × 10−3 kPa−1 was obtained. Theoretical modeling was conducted based on an energy method to predict the load–displacement relationship for various sensor configurations. By adjusting the Young's modulus of the two conversion layers, as well as the geometrical dimensions, the measurement ranges, and sensitivities of the sensors can be quantitatively determined. The sensors are being used for pressure measurements between the human body and garments, shoes, beds, and chairs

  6. Performance Characterization of Solid Oxide Cells Under High Pressure

    DEFF Research Database (Denmark)

    Sun, Xiufu; Bonaccorso, Alfredo Damiano; Graves, Christopher R.;

    2015-01-01

    In this work, recent pressurized test results of a planar Ni- YSZ (YSZ: Yttria stabilized Zirconia) supported solid oxide cell are presented. Measurements were performed at 800 C in both fuel cell and electrolysis mode at different pressures. A comparison of the electrochemical performance of the...... cell at 1 and 3 bar shows a significant and equal performance gain at higher pressure in both fuel cell mode and electrolysis mode. Electrochemical impedance spectroscopy revealed that the serial resistance was not affected by the operation pressure; all the other processes that are dependent on...

  7. Characterization of high-pressure-treated egg albumen.

    Science.gov (United States)

    Iametti, S; Donnizzelli, E; Pittia, P; Rovere, P P; Squarcina, N; Bonomi, F

    1999-09-01

    Addition of NaCl or sucrose to egg albumen prior to high-pressure treatment (up to 10 min at 800 MPa) prevented insolubilization or gel formation after pressure treatment. As a consequence of protein unfolding, the treated albumen had increased viscosity but retained its foaming and heat-gelling properties. Susceptibility of egg albumen proteins to hydrolysis by trypsin increased dramatically after pressure treatment. The S-form of ovalbumin, the presence of which is an index of egg aging, was not found in any of the pressure-treated samples, which also did not display evidence for covalent protein aggregation. However, recognition of ovalbumin by an anti-ovalbumin antiserum was reduced to 40% of that of untreated sample. PMID:10552693

  8. Characterizing the Pressure Smoothing Scale of the Intergalactic Medium

    Science.gov (United States)

    Kulkarni, Girish; Hennawi, Joseph F.; Oñorbe, Jose; Rorai, Alberto; Springel, Volker

    2015-10-01

    The thermal state of the intergalactic medium (IGM) at z structure of the IGM on ˜100 kpc scales, where, analogous to the classical Jeans argument, the pressure of the T ≃ 104 K gas supports it against gravity. We simulate the IGM using smoothed particle hydrodynamics, and find that, at z function with cutoff at λF, allowing us to rigorously quantify the pressure smoothing scale for the first time: we find λF = 79 kpc (comoving) at z = 3 for our fiducial thermal model. This statistic has the added advantage that it directly relates to observations of correlated Lyα forest absorption in close quasar pairs, recently proposed as a method to measure the pressure smoothing scale. Our results enable one to quantify the pressure smoothing scale in simulations, and ask meaningful questions about its dependence on reionization and thermal history. Accordingly, the standard description of the IGM in terms of the amplitude T0 and slope γ of the temperature-density relation T={T}0{(ρ /\\bar{ρ })}γ -1 should be augmented with a third pressure smoothing scale parameter λF.

  9. Temporal variation of diatom benthic propagules in a monsoon-influenced tropical estuary

    Science.gov (United States)

    Patil, Jagadish S.; Anil, Arga Chandrashekar

    2008-10-01

    Temporal variations in the diatom benthic propagule (DBP) community and their role in the phytoplankton community in a monsoon-affected tropical estuary, Zuari estuary, Goa (India) are presented. The DBP from the sediments was enumerated using an extinction dilution method (most probable number method), which allows estimation of resting stages through examination of germinated vegetative cells in culture. The DBP community was dominated by planktonic species belonging to the genera Skeletonema, Fragilariopsis, Thalassiosira, and Chaetoceros. Benthic propagules (BPs) of Skeletonema costatum and Fragilariopsis sp. were dominant throughout the year. Between these two species, only S. costatum showed a linear relationship between the BP and planktonic cells, indicating that this species is particularly important in coupling of pelagic and benthic ecosystems. During the onset and restart of monsoon after an intermittent break, water column was stratified, with a low-salinity layer arising from riverine discharge and precipitation at the surface and relatively cold, saline, low-oxygen waters at the bottom. Stratification favored blooming of S. costatum and Fragilariopsis sp. in nutrient-rich surface and bottom waters, respectively. The decline in these blooms ensuing nitrate depletion and salinity change resulted in an increased abundance of BP. Chaetoceros bloom was observed during the monsoon break as well as during non-monsoon period and on both the occasions the decline in bloom was coupled with freshwater discharge. During the non-monsoon season, Thalassiosira blooms were encountered subsequent to high nitrate inputs. These findings suggest that in such shallow tropical regions, physical processes during monsoon (freshwater discharge) and non-monsoon seasons (currents, waves and tides) cause resuspension of diatom BP. Since light is not a limiting factor for germination in such regions, the blooming of resuspended BP depends on nutrient availability.

  10. Investigation of pressurized combustion and characterization of solid fuels

    Energy Technology Data Exchange (ETDEWEB)

    Aho, M.; Haemaelaeinen, J.; Paakkinen, K. [VTT Energy, Espoo (Finland); Joutsenoja, T. [Tampere Univ. of Technology (Finland)

    1997-10-01

    The objective of the research of Technical Research Centre of Finland (VTT) was to produce results of the effects of pressure and other important parameters on the combustion of pulverized coals using both experimental and theoretical methods. The results can be utilized to model pressurized combustion and to plan pilot-scale reactors. The studied coals were Polish hvb coal, French lignite (Gardanne), German anthracite (Niederberg) and German (Goettelborn) hvb coal. In was originally planned to study also a char of one of these coals. However, anthracite was selected instead of char, because the theoretical studies predicted maximum pressure effect to be found for antracite-type coals (with low reactivity and low content of volatiles). The pulverized coal samples were combusted in an electrically heated, pressurized entrained flow reactor (PEFR), where the experimental conditions were controlled with a high precision. The studied particle size fractions were 100-125 Em and 140-180 Am for anthracite and 140-180 {mu}m for the other coals. The studied things were combustion rates and temperatures of burning particles. Two types of sets of experiments were carried out. In the first case, experimental planning was done and the results were handled with multivariable partial least squares (PLS) method. Gas temperature varied from 1073K to 1473K and pressure from 0.2 MPa to 0.8 MPa. The other variables were PO2 and PCO{sub 2}. Some of the experiments were carried out at conditions prevailing during flue gas recirculation (CO{sub 2} concentration was > 20 vol%). In the second case, oxygen concentration was kept constant ( 10 vol%) and pressure was varied from 0.2 MPa to 0.8 MPa with an interval of 0.1 MPa

  11. In Vitro and in vivo characterization of wireless and passive micro system enabling gastrointestinal pressure monitoring.

    Science.gov (United States)

    Shi, Qiang; Wang, Junbo; Chen, Deyong; Chen, Jian; Li, Jing; Bao, Kaikai

    2014-12-01

    This paper presents a wireless and passive micro pressure system based on the LC mutual inductance detection mechanism for gastrointestinal (GI) pressure monitoring. The micro pressure system is composed of a sensor capsule (a pressure sensitive micro capacitive sensor in series with an induction coil to form an LC tank) and a detection unit (a detection coil connected with a network analyzer). The pressure variations under measurement lead to changes in the capacitance of the pressure sensor and therefore a shift in the LC tank resonant frequency, quantified by the impedance measurement of the detection coil. The pressure sensor was fabricated using microfabrication processes with key parameters optimized. The in vitro characterization of the micro pressure system recorded a sensitivity of 0.2491 kHz/kPa (-10 kPa to 30 kPa). One-month rabbit stomach pressure monitoring was conducted based on the developed micro pressure system as a confirmation of device long term in vivo stability. Furthermore, rabbit stomach pressure variations before and after food feeding was recorded and compared where three distinctive contraction patterns (random contraction with low amplitude, irregular strong contractions and regular contraction in a cyclic manner) following food feeding were located. Compared to previous reported GI pressure sensors, this LC tank is featured with simple device structure without batteries and electrical components for energy transfer. Both in vitro and in vivo characterization confirm the functionality of the system, which may enable the gastrointestinal motility study in the near future. PMID:25119603

  12. Preparation and Characterization of Silica Aerogels Derived from Ambient Pressure

    Institute of Scientific and Technical Information of China (English)

    Jun SHEN; Zhihua ZHANG; Guangming WU; Bin ZHOU; Xingyuan NI; Jue WANG

    2006-01-01

    Silica aerogels were prepared by sol-gel technique from industrial silicon derivatives (polyethoxydisiloxanes, E40), followed by silylation and drying under ambient pressure. The specific surface area, pore size distribution and thermal conductivity of the silica aerogels were investigated and the results showed that the diameter of the silica particles is about 6 nm and the average pore size of the silica aerogels is 14.7 nm. The specific temperature and pressure of 1.01×105 Pa. The Si-CH3 groups were also detected on the internal surface of the silica aerogels, which show hydrophobic. Silica aerogels derived by this technique is low cost and have wide applications.

  13. Characterization of a low pressure supersonic plasma jet

    International Nuclear Information System (INIS)

    Plasma assisted supersonic jet deposition (PA-SJD) is a technique which combines a inductively coupled plasma (ICP) with a supersonic jet for the fabrication of thin films having a desired morphology. A reactive argon-oxygen plasma is employed to dissociate an organic precursor (titanium tetra-isopropoxide for TiO2 thin films) in a first vacuum chamber which is connected through a nozzle to a lower pressure chamber. The pressure difference produces a supersonic jet, seeded with nanoparticles. Along the jet the nucleation and aggregation of nanoparticles can be controlled to obtain nanostructured depositions. We report here the results of an analysis performed with a quadrupole mass spectrometer (QMS) which was used to sample neutrals and ions from the jet at different positions along the centerline of the supersonic expansion

  14. Fabrication and characterization of magnetic composite membrane pressure sensor

    KAUST Repository

    Khan, Mohammed Asadullah

    2016-04-20

    This paper describes a magnetic field powered pressure sensor, which comprises a coil array and a magnetic composite membrane. The composite membrane is made by embedding a ribbon of the amorphous soft magnetic alloy Vitrovac®, in a 17 mm x 25 mm x 1.5 mm Polydimethylsiloxane (PDMS) layer. PDMS is chosen for its low Young\\'s modulus and the amorphous alloy for its high permeability. The membrane is suspended 1.5 mm above a 17x19 array of microfabricated planar coils. The coils are fabricated by patterning a 620 nm thick gold layer. Each coil occupies an area of 36000 μm2 and consists of 14 turns. The sensor is tested by subjecting it to pressure and simultaneously exciting it by a 24 A/m, 100 kHz magnetic field. A pressure change from 0 kPa to 5.1 kPa, results in a 5400 ppm change in the voltage output.

  15. Characterization of Dust-Plasma Interactions In Non-Thermal Plasmas Under Low Pressure and the Atmospheric Pressure

    Science.gov (United States)

    Bilik, Narula

    This dissertation research focuses on the experimental characterization of dust-plasma interactions at both low and atmospheric pressure. Its goal is to fill the knowledge gaps in (1) the fundamental research of low pressure dusty plasma electrons, which mainly relied on models with few experimental results; and (2) the nanoparticle synthesis process in atmospheric pressure uniform glow plasmas (APGDs), which is largely unexplored in spite of the economical advantage of APGDs in nanotechnology. The low pressure part of the dissertation research involves the development of a complete diagnostic process for an argon-siline capacitively-coupled RF plasma. The central part of the diagnostic process is the Langmuir probe measurement of the electron energy probability function (EEPF) in a dusty plasma, which has never been measured before. This is because the dust particles in the plasma cause severe probe surface contamination and consequently distort the measurement. This problem is solved by adding a solenoid-actuated shield structure to the Langmuir probe, which physically protects the Langmuir probe from the dust particle deposition to ensure reliable EEPF measurements. The dusty plasma EEPFs are characterized by lower electron density and higher electron temperature accompanied by a drop in the low energy electron population. The Langmuir probe measurement is complemented with other characterizations including the capacitive probe measurement, power measurement, and dust particle collection. The complete diagnostic process then gives a set of local plasma parameters as well as the details of the dust-electron interactions reflected in the EEPFs. This set of data serves as input for an analytical model of nanoparticle charging to yield the time evolution of nanoparticle size and charge in the dusty plasma. The atmospheric pressure part of the dissertation focuses on the design and development of an APGD for zinc oxide nanocrystal synthesis. One of the main

  16. Electrical characterization of atmospheric pressure DBD in air

    International Nuclear Information System (INIS)

    Atmospheric pressure dielectric barrier discharge (DBD) in air was generated between two rectangular copper electrodes covering the lower electrode with a dielectric (glass or polycarbonate -PC) using low frequency (line frequency-50Hz) high voltage power supply. The discharge was studied for inter-electrode gap spacing in the range of 2 mm – 5 mm and their influence on breakdown voltage. Voltage-current characteristics and the analysis of the distribution of current pulses per half cycle of the current waveform indicated that the discharge is more uniform in 3 mm inter-electrode gap spacing with PC as a dielectric rather than glass. (author)

  17. Characterization of a steam plasma jet at atmospheric pressure

    International Nuclear Information System (INIS)

    An atmospheric steam plasma jet generated by an original dc water plasma torch is investigated using electrical and spectroscopic techniques. Because it directly uses the water used for cooling electrodes as the plasma-forming gas, the water plasma torch has high thermal efficiency and a compact structure. The operational features of the water plasma torch and the generation of the steam plasma jet are analyzed based on the temporal evolution of voltage, current and steam pressure in the arc chamber. The influence of the output characteristics of the power source, the fluctuation of the arc and current intensity on the unsteadiness of the steam plasma jet is studied. The restrike mode is identified as the fluctuation characteristic of the steam arc, which contributes significantly to the instabilities of the steam plasma jet. In addition, the emission spectroscopic technique is employed to diagnose the steam plasma. The axial distributions of plasma parameters in the steam plasma jet, such as gas temperature, excitation temperature and electron number density, are determined by the diatomic molecule OH fitting method, Boltzmann slope method and Hβ Stark broadening, respectively. The steam plasma jet at atmospheric pressure is found to be close to the local thermodynamic equilibrium (LTE) state by comparing the measured electron density with the threshold value of electron density for the LTE state. Moreover, based on the assumption of LTE, the axial distributions of reactive species in the steam plasma jet are estimated, which indicates that the steam plasma has high chemical activity.

  18. Evanescent high pressure during hypersonic cluster-surface impact characterized by the virial theorem.

    Science.gov (United States)

    Gross, A; Levine, R D

    2005-11-15

    Matter under extreme conditions can be generated by a collision of a hypersonic cluster with a surface. The ultra-high-pressure interlude lasts only briefly from the impact until the cluster shatters. We discuss the theoretical characterization of the pressure using the virial theorem and develop a constrained molecular-dynamics procedure to compute it. The simulations show that for rare-gas clusters the pressures reach the megabar range. The contribution to the pressure from momentum transfer is comparable in magnitude and is of the same sign as that ("the internal pressure") due to repulsive interatomic forces. The scaling of the pressure with the reduced mechanical variables is derived and validated with reference to the simulations. PMID:16321088

  19. Pressurized water reactor nuclear power plant. Environmental characterization information report

    International Nuclear Information System (INIS)

    The typical plant chosen for characterization is a 10000-MWe nameplate rating with wet-natural-draft cooling towers and modern radwaste control and processing equipment. The process, plant operating parameters, resources needed, and the environmental residuals and products associated with the power plant are presented. Annual resource usage and pollutant discharges are shown in English and metric units, assuming an annual plant capacity factor of 70%. In addition to annual quantities, the summary table gives quantities in terms of 1012 Btu (about 293 million kWh) of electrical energy produced for comparison among energy processes. Supporting information and calculation procedures for the data are given. Thirteen environmental points of interest are discussed individually. Cost information, typical radioactive releases, and use of cooling ponds as an alternative cooling method are discussed in appendixes. A glossary and list of acronyms and abbreviations are provided

  20. Morphological structure of propagules and electrophoretic karyotype analysis of false smut Villosiclava virens in rice.

    Science.gov (United States)

    Fu, Rongtao; Ding, Lei; Zhu, Jun; Li, Ping; Zheng, Ai-Ping

    2012-04-01

    The target pathogen Villosiclava virens (teleomorph: claviceps oryzae-sativae) was isolated from the infected rice, where it caused false smut. In our study, the forming processes of the chlamydospores, chlamydospore balls, conidiospores, and secondary conidiospores during the asexual reproduction were observed more precisely and in greater detail than previous descriptions. The microstructure of the infected rice kernel showed that the outer dense chlamydospores piled around the false smut balls grown on XBZ medium; moreover the sclerotia consisting of dense mycelium were found. The different morphology was observed across the different growing conditions. In addition, we observed the nuclear numbers of both the conidiospores and hyphae using 4',6-diamidino-2-phenylindole (DAPI) staining. Because the fungus has small chromosomes and the numbers were not previously known, we analyzed the electrophoretic karyotype using a pulsed field gel electrophoresis (PFGE) technique. The results showed that V. virens has at least 10 chromosomes ranging in size from 0.6 kb to 6 Mb. The V. virens genome size is estimated to be 23 Mb. Here, we report the morphological characteristics of the fungus and the process of asexual spores forming asexual propagules, along with the first analyze the molecular karyotype of V. virens. These results supply a foundation for further study of the pathogenicity and biology of this devastating pathogen. PMID:22538655

  1. Mating system, pollen and propagule dispersal, and spatial genetic structure in a high-density population of the mangrove tree Kandelia candel.

    Science.gov (United States)

    Geng, Qifang; Lian, Chunlan; Goto, Susumu; Tao, Jianmin; Kimura, Megumi; Islam, Md Sajedul; Hogetsu, Taizo

    2008-11-01

    Mangrove tree species form ecologically and economically important forests along the tropical and subtropical coastlines of the world. Although low intrapopulation genetic diversity and high interpopulation genetic differentiation have been detected in most mangrove tree species, no direct investigation of pollen and propagule dispersal through paternity and/or parentage analysis and spatial genetic structure within populations has been conducted. We surveyed the mating system, pollen and propagule dispersal, and spatial genetic structure in a natural population of Kandelia candel, one of the typical viviparous mangrove tree species, using nuclear and chloroplast microsatellite markers. High diversity and outcrossing rates were observed. Paternity and parentage analysis and modelling estimations revealed the presence of an extremely short-distance component of pollen and propagule dispersal (pollen: 15.2+/-14.9 m (SD) by paternity analysis and 34.4 m by modelling; propagule: 9.4+/-13.8 m (SD) by parentage analysis, and 18.6 m by modelling). Genetic structure was significant at short distances, and a clumped distribution of chloroplast microsatellite genotypes was seen in K. candel adults. We conclude that the K. candel population was initiated by limited propagule founders from outside by long-distance dispersal followed by limited propagule dispersal from the founders, resulting in a half-sib family structure. PMID:19140988

  2. Non-isothermal melt crystallization of poly(tetramethylene succinate) under high pressure: Characterization and kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Rohindra, David [Graduate School of Engineering, Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1-S8-33, O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); School of Biological and Chemical Sciences, Faculty of Science, Technology and Environment, The University of the South Pacific, Suva (Fiji); Kuboyama, Keiichi [Graduate School of Engineering, Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1-S8-33, O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); Ougizawa, Toshiaki, E-mail: tougizawa@op.titech.ac.jp [Graduate School of Engineering, Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1-S8-33, O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2012-10-10

    Highlights: Black-Right-Pointing-Pointer Non-isothermal crystallization of PTMS under high pressure is reported. Black-Right-Pointing-Pointer Nucleation pattern analyzed using Ozawa model. Black-Right-Pointing-Pointer Crystallization and nucleation behavior changed above 300 MPa. - Abstract: The non-isothermal melt crystallization behavior (characterization and kinetics) of poly(tetramethylene succinate) (PTMS) under high pressure was investigated using high pressure differential thermal analysis (HP-DTA). Wide angle X-ray diffraction (WAXD), small angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), polarized optical microscopy (POM), and density measurement were used to study the crystal structure, the melting temperature and the morphology of the samples crystallized under various pressures. No new crystal structure or formation of extended chain crystals were found in the pressure crystallized samples. Optical micrographs revealed nucleation density decreased and spherulite morphology changed (presence of banding pattern) above 300 MPa. DTA crystallization curves showed a single exothermic peak at all pressures which shifted to higher temperatures with increasing pressure and became broad above 300 MPa. The kinetics was studied using the Ozawa model. A change in the nucleation pattern was predicted from the Ozawa exponent, instantaneous at low pressures and sporadic above 300 MPa. From kinetic and morphological results it was found that a critical pressure region existed around 300 MPa.

  3. Pulse Rise Time Characterization of a High Pressure Xenon Gamma Detector for use in Resolution Enhancement

    CERN Document Server

    Troyer, G L

    2000-01-01

    High pressure xenon ionization chamber detectors are possible alternatives to traditional thallium doped sodium iodide (NaI(Tl)) and hyperpure germanium as gamma spectrometers in certain applications. Xenon detectors incorporating a Frisch grid exhibit energy resolutions comparable to cadmium/zinc/telluride (CZT) (e.g. 2% (at) 662keV) but with far greater sensitive volumes. The Frisch grid reduces the position dependence of the anode pulse risetimes, but it also increases the detector vibration sensitivity, anode capacitance, voltage requirements and mechanical complexity. We have been investigating the possibility of eliminating the grid electrode in high-pressure xenon detectors and preserving the high energy resolution using electronic risetime compensation methods. A two-electrode cylindrical high pressure xenon gamma detector coupled to time-to-amplitude conversion electronics was used to characterize the pulse rise time of deposited gamma photons. Time discrimination was used to characterize the pulse r...

  4. Fabrication and Characterization of a Pressure Sensor using a Pitch-based Carbon Fiber

    International Nuclear Information System (INIS)

    This paper reports fabrication and characterization of a pressure sensor using a pitch-based carbon fiber. Pitch-based carbon fibers have been shown to exhibit the piezoresistive effect, in which the electric resistance of the carbon fiber changes under mechanical deformation. The main structure of pressure sensors was built by performing backside etching on a SOI wafer and creating a suspended square membrane on the front side. An AC electric field which causes dielectrophoresis was used for the alignment and deposition of a carbon fiber across the microscale gap between two electrodes on the membrane. The fabricated pressure sensors were tested by applying static pressure to the membrane and measuring the resistance change of the carbon fiber. The resistance change of carbon fibers clearly shows linear response to the applied pressure and the calculated sensitivities of pressure sensors are 0.25∼0.35 and 61.8 Ω/kΩ·bar for thicker and thinner membrane, respectively. All these observations demonstrated the possibilities of carbon fiber-based pressure sensors

  5. Characterization of piezocrystals for practical configurations with temperature- and pressure-dependent electrical impedance spectroscopy.

    Science.gov (United States)

    Qiu, Zhen; Sadiq, Muhammad R; Démoré, Christine; Parker, Michelle F; Marin, Pablo; Mayne, Keith; Cochran, Sandy

    2011-09-01

    Piezoelectric single crystal materials such as (x)Pb(Mg(1/3)Nb(2/3))O(3-)(1-x)PbTiO(3) (PMN-PT) have, by some measures, significantly better performance than established piezoelectric ceramics for ultrasound applications. However, they are also subject to phase transitions affecting their behavior at temperatures and pressures encountered in underwater sonar and actuator applications and in non-destructive testing at elevated temperatures. Materials with modified compositions to reduce these problems are now under development, but application-oriented characterization techniques need further attention. Characterization with temperature variation has been reported extensively, but the range of parameters measured is often limited and the effects of pressure variation have received almost no attention. Furthermore, variation in properties between samples is now rarely reported. The focus of this paper is an experimental system set up with commercially available equipment and software to carry out characterization of piezoelectric single crystals with variation in temperature, pressure, and electrical bias fields found in typical practical use. We illustrate its use with data from bulk thickness-mode PMN-29%PT samples, demonstrating variation among nominally identical samples and showing not only the commonly reported changes in permittivity with temperature for bulk material but also significant and complicated changes with pressure and bias field and additional ultrasonic modes which are attributed to material phase changes. The insight this provides may allow the transducer engineer to accelerate new material adoption in devices. PMID:21937310

  6. Sea urchin development in a global change hotspot, potential for southerly migration of thermotolerant propagules

    Science.gov (United States)

    Byrne, M.; Selvakumaraswamy, P.; Ho, M. A.; Woolsey, E.; Nguyen, H. D.

    2011-03-01

    The distribution of the sea urchin Heliocidaris erythrogramma coincides with the southeast Australia global change hot spot where marine ecosystems are warming significantly due to changes in ocean circulation. To address questions on future vulnerabilities, the thermotolerance of the planktonic life phase of H. erythrogramma was investigated in the climate and regionally relevant setting of projected near-future (2100) ocean warming. Experimental treatments ranged from 18 to 26 °C, with 26 °C representing +3-4 °C above recent ambient sea-surface temperatures. Developmental success across all stages (gastrula, 24 h; larva, 72 h; juvenile, 120 h) decreased with increasing temperature. Development was tolerant to a +1-2 °C increase above ambient, but significant deleterious effects were evident at +3-4 °C. However, larvae that developed through the early bottleneck of normal development at 26 °C metamorphosed successfully. The inverse relationship between temperature and planktonic larval duration (PLD) was seen in a 25% decrease in the PLD of H. erythrogramma at 24 and 26 oC. Ocean warming may be advantageous to a subset of larvae through early settlement and reduction of the vulnerable planktonic period. This positive effect of temperature may help buffer the negative effects of ocean warming. In parallel studies with progeny derived from northern (Coffs Harbour) and southern (Sydney) H. erythrogramma, northern embryos had significantly higher thermotolerance. This provides the possibility that H. erythrogramma populations might keep up with a warming world through poleward migration of thermotolerant propagules, facilitated by the strong southward flow of the East Australian Current. It is uncertain whether H. erythrogramma populations at the northern range of this species, with no source of immigrants, will have the capacity to persist in a warm ocean. Due to its extensive latitudinal distribution, its potential developmental thermotolerance and

  7. Characterization of a Dielectric Barrier Plasma Gun Discharging at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guang-Qiu; GE Yuan-Jing; ZHANG Yue-Fei; CHEN Guang-Liang

    2004-01-01

    @@ We develop a plasma gun based on dielectric barrier discharge and working at atmospheric pressure. A theoretical model to predict the gun discharge voltage is built, which is in agreement with the experimental results. After investigating the characterization of discharging gun and utilizing it for polymerization, we find that the gun can be used as a source to generate a stable uniform plasma for different plasma-processing technologies.

  8. Characterization of Fractured Reservoirs Using a Combination of Downhole Pressure and Self-Potential Transient Data

    OpenAIRE

    Yuji Nishi; Tsuneo Ishido

    2012-01-01

    In order to appraise the utility of self-potential (SP) measurements to characterize fractured reservoirs, we carried out continuous SP monitoring using multi Ag-AgCl electrodes installed within two open holes at the Kamaishi Mine, Japan. The observed ratio of SP change to pressure change associated with fluid flow showed different behaviors between intact host rock and fractured rock regions. Characteristic behavior peculiar to fractured reservoirs, which is predicted from numerical simulati...

  9. Characterizing catches taken by different gears as a step towards evaluating fishing pressure on fish communities

    OpenAIRE

    Fauconnet, Laurence; Trenkel, Verena M.; Morandeau, Gilles; Caill-milly, Nathalie; Rochet, Marie-joelle

    2015-01-01

    To implement an ecosystem approach to fisheries management, there is a need to characterize the total pressure exerted by fisheries at the community level. French onboard observer data were used to derive catch metrics and compare fishing distribution across community components between two sites in the Southern Bay of Biscay. Sample-based rarefaction curves were used to standardize metrics across different active and passive gears, and correct for sample size differences. Six metrics for spe...

  10. Hydrogen embrittlement characterization by disk pressure tests: Test analysis and application to high chromium martensitic steels

    International Nuclear Information System (INIS)

    The paper reports and discusses the results of an experimental and numerical activity, aimed to the characterization of the influence of hydrogen on the mechanical properties of a few high chromium martensitic steels which are candidates for fusion reactor and chemical applications. Experiments were conducted with the Disk Pressure Test technique, according to which a circular thin specimen is loaded up to rupture by a uniform pressure. As a detailed analysis of the stress/strain distributions in the specimen was not available, this kind of test being mainly used to obtain comparative information about different materials, a nonlinear numerical (Finite Element) model of the specimen was set up, by which stress and strain could be accurately evaluated as a function of the applied pressure. This model was employed both for interpreting experimental results and to achieve a more general understanding of the capabilities of the Disk Pressure Test for the characterization of hydrogen embrittlement effects. The calculated strain at failure showed the typical dependence on hydrogen content, falling to very low levels as a threshold concentration is exceeded

  11. Characterization of the full cone pressure swirl spray nozzles for the nuclear reactor containment spray system

    International Nuclear Information System (INIS)

    Highlights: • Full cone spray pressure swirl nozzle with X-Vane is studied. • Laser illuminated imaging technique is used. • Correlations for coefficient of discharge, spray cone angle and SMD are suggested. • Droplet size and mass fraction distribution is measured. • Inviscid theory predicts the coefficient of discharge. - Abstract: The objective of the present study is to characterize a full cone pressure swirl nozzle for the Containment Spray System (CSS) of Indian Pressurized heavy Water reactors (IPHWR). The influence of Reynolds number and geometric parameters on the coefficient of discharge, spray cone angle, mass flux density distribution, droplet size distribution, Sauter mean diameter (SMD is studied for full cone pressure swirl full cone nozzles. The nozzles of orifice diameter range from 1.3 to 7.2 mm are studied. Experiments are conducted with water at room temperature as the working medium. The nozzles are operated with the pressure ranging from 1 to 8 bar. The measurements of the drop size distributions are performed with laser illuminated imaging technique. The spray cone-angle of the full cone nozzles is measured by the evaluation of images recorded with a camera using IMAGE J software. Correlations for coefficient of discharge, spray cone angle and Sauter mean diameter are suggested on the basis of the experimental results. Rosin–Rammler model and Nukiyama–Tanasawa distributions predict the mass fraction distribution reasonably well. However, the droplet size distribution is predicted by Nukiyama-Tanasawa model only

  12. The use of pneumatically generated water pressure signals for aquifer characterization

    Science.gov (United States)

    Fort, M.; Roberts, R.; Chace, D.

    2013-12-01

    The use of pneumatically generated pressure signals for aquifer characterization Hydraulic tests are the most reliable method of obtaining estimates of hydrologic properties, such as conductivity, that are essential for flow and transport modeling. The use of a sinusoidal signal for hydraulic testing is well established, with Streltsova (1988), Rasmussen (2003) and others having developed analytic solutions. Sinusoidal tests provide a unique easily distinguished signal that reduces ambiguity during analysis and we show that a sinusoidal pressure signal propagates farther into the formation than a standard slug-test signal. If a sinusoidal test is combined with a slug and/or a constant rate test, it can further reduce uncertainty in the estimated parameter values. We demonstrate how pneumatic pressure can be used to generate all three of these signals. By positioning pressure transducers both below the water level and in the head space above the water, we can monitor the total pressure acting on the formation and the changes in water level. From the changes in water level, it is possible to calculate the flow rate in and out of the well, assuming that the well diameter and water density are known. Using gas flow controllers with a Supervisory Control And Data Acquisition (SCADA) system we are able to precisely control the pressures in the well. The use of pneumatic pressure has the advantage that it requires less equipment (no pumps) and produces no water. We also show how the numerical well test analysis program nSIGHTS can be used to analyze all three types of tests simultaneously and to assess the relative contribution of each type of test to the parameter estimation. nSIGHTS was recently released as open source by Sandia National Laboratories and is available for free.

  13. Pulse Rise Time Characterization of a High Pressure Xenon Gamma Detector for use in Resolution Enhancement

    International Nuclear Information System (INIS)

    High pressure xenon ionization chamber detectors are possible alternatives to traditional thallium doped sodium iodide (NaI(Tl)) and hyperpure germanium as gamma spectrometers in certain applications. Xenon detectors incorporating a Frisch grid exhibit energy resolutions comparable to cadmium/zinc/telluride (CZT) (e.g. 2% (at) 662keV) but with far greater sensitive volumes. The Frisch grid reduces the position dependence of the anode pulse risetimes, but it also increases the detector vibration sensitivity, anode capacitance, voltage requirements and mechanical complexity. We have been investigating the possibility of eliminating the grid electrode in high-pressure xenon detectors and preserving the high energy resolution using electronic risetime compensation methods. A two-electrode cylindrical high pressure xenon gamma detector coupled to time-to-amplitude conversion electronics was used to characterize the pulse rise time of deposited gamma photons. Time discrimination was used to characterize the pulse rise time versus photo peak position and resolution. These data were collected to investigate the effect of pulse rise time compensation on resolution and efficiency

  14. Spatial characterization of laser induced Yb plasma in argon using optical emission spectroscopy: Pressure effect

    International Nuclear Information System (INIS)

    Highlights: • Laser induced Yb plasma at different pressure of Argon is spatially investigated. • O-TOF profiles and excitation temperature are used to characterize the plasma. • At 100 Pa of argon background gas, shock wave begins to be formed. • Drag force expansion describes the plasma propagation at pressures bigger than 1 Pa. • Two components of velocity distribution of the Yb atoms are estimated. - Abstract: Spatial and temporal behavior of laser induced Ytterbium plasma plume is studied using optical emission spectroscopy technique. A third harmonic Nd:YAG nanosecond laser was used to generate Yb plasma plume at different Argon background pressures (1, 10, 102, 103 and 104 Pa). The plasma dynamics was investigated based on the spatial behavior of the excitation temperature coupled with optical time of flight (O-TOF) profiles of neutral Yb emission line (555.65 nm) along the propagation axe of the plasma plume. Drag force model was appropriate to describe the propagation dynamics at all pressures except of the lowest one (1 Pa) where free expansion model is dominant. The velocity distribution of Yb I atoms were extracted using two terms of Shifted Maxwell–Boltzmann (SMB) distribution. The correlation between the spatial comportment of both excitation temperature and O-TOF profiles is discussed

  15. Characterization of atmospheric pressure microplasma produced from argon and a mixture of argon–ethylenediamine

    International Nuclear Information System (INIS)

    A non-thermal atmospheric pressure microplasma generated from pure argon (Ar) and a mixture of argon–ethylenediamine vapors (Ar/EDA) has been characterized in this study. A sinusoidal power supply operating at 30 kHz was used to excite microplasma in a rectangular borosilicate glass capillary (4×0.4 mm2). The monomer EDA was mixed with Ar in order to perform plasma polymerization inside the microchannel. The analyses were made by measuring spectroscopic and electrical parameters of the discharge. The effects of EDA mixing on plasma parameters such as electron, excitation and rotational temperatures during the process of surface coating of the microchannel were investigated. These parameters play an important role in the deposition process. The plasma temperatures estimated through spectroscopic measurement were found in the sequence Te>Texc>Tvib>Trot, which indicated the non-thermal characteristics of the proposed DBD microplasma. The parameters of the Ar discharge were also numerically computed using plasma simulations. The numerical predictions of electron temperature (2D simulations) and electron density (3D simulations) were found to be in close agreement to those estimated through experiments. - Highlights: • An atmospheric pressure microplasma was generated in a borosilicate glass capillary. • A pure argon and a mixture of argon–ethylenediamine plasmas were characterized. • Characterization was performed by emission spectrometry and electrical measurements. • Plasma parameters were also predicted by numerical simulations. • The sequence of estimated plasma temperatures indicated its non-thermal behaviour

  16. New nitrogen-containing materials for hydrogen storage and their characterization by high-pressure microbalance

    DEFF Research Database (Denmark)

    Vestbø, Andreas Peter

    Hydrogen storage for practical applications is under intense scrutiny worldwide since hopes are prevalent of being able to use hydrogen as energy vector in a continually difficult time in terms of having access to clean and affordable energy in the world. Hydrogen can be stored in compressed or...... liquid form, technologies that are well developed and usable, but not energy efficient. Certain metals and alloys are able to contain hydrogen within practical pressure and temperature ranges very efficient volume-wise, but they are too heavy for use in cars. Recently, attention has turned to the so...... introduction in Chapter 1, Chapter 2 of the text deals with general principles and an overview for hydrogen storage in solid materials. Chapter 3-5 deals with the development of an in-house high pressure microbalance in a glovebox built from scratch for the use of characterizing new hydrogen storage materials...

  17. The role of large wood in retaining fine sediment, organic matter and plant propagules in a small, single-thread forest river

    Science.gov (United States)

    Osei, Nana A.; Gurnell, Angela M.; Harvey, Gemma L.

    2015-04-01

    This paper investigates associations among large wood accumulations, retained sediment, and organic matter and the establishment of a viable propagule bank within a forested reach of a lowland river, the Highland Water, UK. A wood survey within the 2-km study reach, illustrates that the quantity of wood retained within the channel is typical of relatively unmanaged river channels bordered by deciduous woodland and that the wood accumulations (jams) that are present are well developed, typically spanning the river channel and comprised of wood that is well decayed. Sediment samples were obtained in a stratified random design focusing on nine subreaches within which samples were aggregated from five different types of sampling location. Two of these locations were wood-associated (within and on bank faces immediately adjacent to wood jams), and the other three locations represented the broader river environment (gravel bars, bank faces, floodplain). The samples were analysed to establish their calibre, organic, and viable plant propagule content. The gravel bar sampling locations retained significantly coarser sediment containing a lower proportion of organic matter and viable propagules than the other four sampling locations. The two wood-related sampling locations retained sediment of intermediate calibre between the gravel bar and the bank-floodplain samples but they retained significantly more organic matter and viable propagules than were found in the other three sampling locations. In particular, the jam bank samples (areas of sediment accumulation against bank faces adjacent to wood jams) contained the highest number of propagules and the largest number of propagule species. These results suggest that retention of propagules, organic matter and relatively fine sediment in and around wood jams has the potential to support vegetation regeneration, further sediment retention, and as a consequence, landform development within woodland streams, although this

  18. Effects of propagule density and survival strategies on establishment and growth: further investigations in the phylloplane fungal model system.

    Science.gov (United States)

    Nix-Stohr, Shannon; Moshe, Riina; Dighton, John

    2008-01-01

    This work builds on an earlier culture study where we determined that species diversity of competing saprotrophic phyllpolane fungi had only a negligible effect on the establishment and coexistence of a target fungus, Pestalotia vaccinii. Here, we explore preliminary evidence suggesting that spore density is a more important contributing factor to colonization and coexistence. We examine the influence of propagule density in vitro on establishment and growth of select members of the phylloplane of Vaccinium macrocarpon (American cranberry). To evaluate the response of the weak pathogen P. vaccinii to changes in competitors spore density, we chose saprotrophs from the previous investigation that had the greatest inhibitory effect on the establishment of P. vaccinii (Curvularia lunata), an intermediate inhibitory effect (Alternaria alternata) and the least inhibitory effect (Penicillium sp.). A constant target spore concentration of 50 viable spores of P. vaccinii was pit against densities of the three individual competitors ranging between 12 and 200 spores. As viable propagule density increased, establishment and coexistence of P. vaccinii significantly decreased, with C. lunata and A. alternata decreasing the growth of P. vaccinii more than Penicillium sp. Concomitantly, both C. lunata and Penicillium sp. were not significantly affected by overall spore density but were significantly affected by the presence of P. vaccinii. A. alternata, on the other hand, was not significantly influenced by the presence of P. vaccinii but was significantly affected by overall spore density. An in vitro investigation into the effect of interspecific competition on mycelial growth suggests how different survival strategies and community assembly rules might influence both growth and development. Growth of P. vaccinii was significantly less when interacting with C. lunata than when interacting with either A. alternata or Penicillium sp. Conversely, P. vaccinii had the greatest

  19. Electrical characterization of high-pressure reactive sputtered ScOx films on silicon

    International Nuclear Information System (INIS)

    Al/ScOx/SiNx/n-Si and Al/ScOx/SiOx/n-Si metal-insulator-semiconductor capacitors have been electrically characterized. Scandium oxide was grown by high-pressure sputtering on different substrates to study the dielectric/insulator interface quality. The substrates were silicon nitride and native silicon oxide. The use of a silicon nitride interfacial layer between the silicon substrate and the scandium oxide layer improves interface quality, as interfacial state density and defect density inside the insulator are decreased.

  20. Characterization of a Setup to test the Impact of High-Amplitude Pressure Waves on Living Cells

    Science.gov (United States)

    Schmidt, Mischa; Kahlert, Ulf; Wessolleck, Johanna; Maciaczyk, Donata; Merkt, Benjamin; Maciaczyk, Jaroslaw; Osterholz, Jens; Nikkhah, Guido; Steinhauser, Martin O.

    2014-01-01

    The impact of pressure waves on cells may provide several possible applications in biology and medicine including the direct killing of tumors, drug delivery or gene transfection. In this study we characterize the physical properties of mechanical pressure waves generated by a nanosecond laser pulse in a setup with well-defined cell culture conditions. To systematically characterize the system on the relevant length and time scales (micrometers and nanoseconds) we use photon Doppler velocimetry (PDV) and obtain velocity profiles of the cell culture vessel at the passage of the pressure wave. These profiles serve as input for numerical pressure wave simulations that help to further quantify the pressure conditions on the cellular length scale. On the biological level we demonstrate killing of glioblastoma cells and quantify experimentally the pressure threshold for cell destruction.

  1. Characterization of atom clusters in irradiated pressure vessel steels and model alloys

    International Nuclear Information System (INIS)

    In order to characterize the microstructural evolution of the iron solid solution under irradiation, two pressure vessel steels irradiated in service conditions and, for comparison, low copper model alloys irradiated with neutrons and electrons have been studied. The characterization has been carried out mainly thanks to small angle neutron scattering and atom probe experiments. Both techniques lead to the conclusion that clusters develop with irradiations. In Fe-Cu model alloys, copper clusters are formed containing uncertain proportions of iron. In the low copper industrial steels, the feature is more complex. Solute atoms like Ni, Mn and Si, sometimes associated with Cu, segregate as ''clouds'' more or less condensed in the iron solid solution. These silicides, or at least Si, Ni, Mn association, may facilitate the copper segregation although the initial iron matrix contains a low copper concentration. (authors). 24 refs., 3 figs., 2 tabs

  2. Atmospheric-pressure plasma jet characterization and applications on melanoma cancer treatment (B/16-F10)

    Energy Technology Data Exchange (ETDEWEB)

    Mashayekh, Shahriar [Physics Department, Shahid Beheshti University, G.C., Evin, 19839-63113 Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Rajaee, Hajar; Hassan, Zuhir M. [Imonology Department, Faculty of Medical Science, Tarbiat Modarres University, Tehran (Iran, Islamic Republic of); Akhlaghi, Morteza [Laser-Plasma Research Institute, Shahid Beheshti University, G.C., Evin, 19839-63113 Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Shokri, Babak [Physics Department and Laser-Plasma Research Institute, Shahid Beheshti University, G.C., Evin, 19839-63113 Tehran, Islamic Republic of Iran (Iran, Islamic Republic of)

    2015-09-15

    A new approach in medicine is the use of cold plasma for various applications such as sterilization blood coagulation and cancer cell treatment. In this paper, a pin-to-hole plasma jet for biological applications has been designed and manufactured and characterized. The characterization includes power consumption via Lissajous method, thermal behavior of atmospheric-pressure plasma jet by using Infra-red camera as a novel method and using Speicair software to determine vibrational and transitional temperatures, and optical emission spectroscopy to determine the generated species. Treatment of Melanoma cancer cells (B16/F10) was also implemented, and tetrazolium salt dye (MTT assay) and flow cytometry were used to evaluate viability. Effect of ultraviolet photons on cancerous cells was also observed using an MgF{sub 2} crystal with MTT assay. Finally, in-vivo studies on C57 type mice were also done in order to have a better understanding of the effects in real conditions.

  3. Atmospheric-pressure plasma jet characterization and applications on melanoma cancer treatment (B/16-F10)

    Science.gov (United States)

    Mashayekh, Shahriar; Rajaee, Hajar; Akhlaghi, Morteza; Shokri, Babak; Hassan, Zuhir M.

    2015-09-01

    A new approach in medicine is the use of cold plasma for various applications such as sterilization blood coagulation and cancer cell treatment. In this paper, a pin-to-hole plasma jet for biological applications has been designed and manufactured and characterized. The characterization includes power consumption via Lissajous method, thermal behavior of atmospheric-pressure plasma jet by using Infra-red camera as a novel method and using Speicair software to determine vibrational and transitional temperatures, and optical emission spectroscopy to determine the generated species. Treatment of Melanoma cancer cells (B16/F10) was also implemented, and tetrazolium salt dye (MTT assay) and flow cytometry were used to evaluate viability. Effect of ultraviolet photons on cancerous cells was also observed using an MgF2 crystal with MTT assay. Finally, in-vivo studies on C57 type mice were also done in order to have a better understanding of the effects in real conditions.

  4. Atmospheric-pressure plasma jet characterization and applications on melanoma cancer treatment (B/16-F10)

    International Nuclear Information System (INIS)

    A new approach in medicine is the use of cold plasma for various applications such as sterilization blood coagulation and cancer cell treatment. In this paper, a pin-to-hole plasma jet for biological applications has been designed and manufactured and characterized. The characterization includes power consumption via Lissajous method, thermal behavior of atmospheric-pressure plasma jet by using Infra-red camera as a novel method and using Speicair software to determine vibrational and transitional temperatures, and optical emission spectroscopy to determine the generated species. Treatment of Melanoma cancer cells (B16/F10) was also implemented, and tetrazolium salt dye (MTT assay) and flow cytometry were used to evaluate viability. Effect of ultraviolet photons on cancerous cells was also observed using an MgF2 crystal with MTT assay. Finally, in-vivo studies on C57 type mice were also done in order to have a better understanding of the effects in real conditions

  5. Experimental and numerical characterization of wind-induced pressure coefficients on nuclear buildings and chimney exhausts

    Energy Technology Data Exchange (ETDEWEB)

    Ricciardi, Laurent, E-mail: laurent.ricciardi@irsn.fr; Gélain, Thomas; Soares, Sandrine

    2015-10-15

    Highlights: • Experiments on scale models of nuclear buildings and chimney exhausts were performed. • Pressure coefficient fields on buildings are shown for various wind directions. • Evolution of pressure coefficient vs U/W ratio is given for various chimney exhausts. • RANS simulations using SST k–ω turbulence model were performed on most studied cases. • A good agreement is overall observed, with Root Mean Square Deviation lower than 0.15. - Abstract: Wind creates pressure effects on different surfaces of buildings according to their exposure to the wind, in particular at external communications. In nuclear facilities, these effects can change contamination transfers inside the building and can even lead to contamination release into the environment, especially in damaged (ventilation stopped) or accidental situations. The diversity of geometries of facilities requires the use of a validated code for predicting pressure coefficients, which characterize the wind effect on the building walls and the interaction between the wind and chimney exhaust. The first aim of a research program launched by the French Institut de Radioprotection et de Sûreté Nucléaire (IRSN), was therefore to acquire experimental data of the mean pressure coefficients for different geometries of buildings and chimneys through wind tunnel tests and then to validate a CFD code (ANSYS CFX) from these experimental results. The simulations were performed using a steady RANS approach and a two-equation SST k–ω turbulence model. After a mesh sensitivity study for one configuration of building and chimney, a comparison was carried out between the numerical and experimental values for other studied configurations. This comparison was generally satisfactory, averaged over all measurement points, with values of Root Mean Square Deviations lower than 0.15 for most cases.

  6. Experimental and numerical characterization of wind-induced pressure coefficients on nuclear buildings and chimney exhausts

    International Nuclear Information System (INIS)

    Highlights: • Experiments on scale models of nuclear buildings and chimney exhausts were performed. • Pressure coefficient fields on buildings are shown for various wind directions. • Evolution of pressure coefficient vs U/W ratio is given for various chimney exhausts. • RANS simulations using SST k–ω turbulence model were performed on most studied cases. • A good agreement is overall observed, with Root Mean Square Deviation lower than 0.15. - Abstract: Wind creates pressure effects on different surfaces of buildings according to their exposure to the wind, in particular at external communications. In nuclear facilities, these effects can change contamination transfers inside the building and can even lead to contamination release into the environment, especially in damaged (ventilation stopped) or accidental situations. The diversity of geometries of facilities requires the use of a validated code for predicting pressure coefficients, which characterize the wind effect on the building walls and the interaction between the wind and chimney exhaust. The first aim of a research program launched by the French Institut de Radioprotection et de Sûreté Nucléaire (IRSN), was therefore to acquire experimental data of the mean pressure coefficients for different geometries of buildings and chimneys through wind tunnel tests and then to validate a CFD code (ANSYS CFX) from these experimental results. The simulations were performed using a steady RANS approach and a two-equation SST k–ω turbulence model. After a mesh sensitivity study for one configuration of building and chimney, a comparison was carried out between the numerical and experimental values for other studied configurations. This comparison was generally satisfactory, averaged over all measurement points, with values of Root Mean Square Deviations lower than 0.15 for most cases

  7. Characterization of spray atomization and heat transfer of pressure swirl nozzles

    International Nuclear Information System (INIS)

    The spray characteristics and heat transfer performance of pressure swirl nozzles were experimentally investigated in an open loop system. The spray flow structure, droplet Sauter mean diameter, and droplet impingement energy were characterized at predefined axial distances and pressure drops. It was found that the spray cone produced by the pressure swirl nozzles changes from hollow cone to full cone as the axial distance increases. The droplets size initially decreases with the increasing of axial distance but subsequently increases in the investigated range of axial distance, while the droplet impinging Weber number decreases monotonously. The surface temperature distribution was found to be solely dependent on the impinging droplet flux distribution in the non-boiling regime. High surface temperature expands the impinging spray cone and finally changes the impinging droplet flux distribution when the droplets impinge on the heated surface. The effect of nozzle-to-surface distance on heat transfer performance was found to be complex and surface temperature dependent. The heat transfer coefficient was investigated to be rather insensitive to the nozzle-to-surface distance at the full cone spray regime than that in the hollow cone spray regime. An empirical model that correlates the Nusselt number to the impinging Reynolds number, non-dimensional surface temperature and nozzle-to-surface distance was developed to fit the present experimental data with an average error of 14%. (authors)

  8. Characterization of Fractured Reservoirs Using a Combination of Downhole Pressure and Self-Potential Transient Data

    Directory of Open Access Journals (Sweden)

    Yuji Nishi

    2012-01-01

    Full Text Available In order to appraise the utility of self-potential (SP measurements to characterize fractured reservoirs, we carried out continuous SP monitoring using multi Ag-AgCl electrodes installed within two open holes at the Kamaishi Mine, Japan. The observed ratio of SP change to pressure change associated with fluid flow showed different behaviors between intact host rock and fractured rock regions. Characteristic behavior peculiar to fractured reservoirs, which is predicted from numerical simulations of electrokinetic phenomena in MINC (multiple interacting continua double-porosity media, was observed near the fractures. Semilog plots of the ratio of SP change to pressure change observed in one of the two wells show obvious transition from intermediate time increasing to late time stable trends, which indicate that the time required for pressure equilibration between the fracture and matrix regions is about 800 seconds. Fracture spacing was estimated to be a few meters assuming several micro-darcies (10-18 m2 of the matrix region permeability, which is consistent with geological and hydrological observations.

  9. Characterizing mesh size distributions (MSDs) in thermosetting materials using a high-pressure system.

    Science.gov (United States)

    Larché, J-F; Seynaeve, J-M; Voyard, G; Bussière, P-O; Gardette, J-L

    2011-04-21

    The thermoporosimetry method was adapted to determine the mesh size distribution of an acrylate thermoset clearcoat. This goal was achieved by increasing the solvent rate transfer by increasing the pressure and temperature. A comparison of the results obtained using this approach with those obtained by DMA (dynamic mechanical analysis) underlined the accuracy of thermoporosimetry in characterizing the macromolecular architecture of thermosets. The thermoporosimetry method was also used to analyze the effects of photoaging on cross-linking, which result from the photodegradation of the acrylate thermoset. It was found that the formation of a three-dimensional network followed by densification generates a modification of the average mesh size that leads to a dramatic decrease of the meshes of the polymer. PMID:21428423

  10. Spectroscopic characterization of fluorine atoms in atmospheric pressure He/SF6 plasmas

    Institute of Scientific and Technical Information of China (English)

    Huiliang Jin; Bo Wang; Feihu Zhang

    2011-01-01

    We investigate reactive fluorine atom spectroscopic characterization in atmospheric pressure of He/SF6 plasma using atomic emission spectrometry. As input radio frequency (RF) power levels are raised from 140 to 220 W, the emission spectra of 685.60 (3p4D→3s4P transition) and 739.87 nm (3p4P→3s4P transition) increase significantly. Moreover, an optimal value of SF6 volume concentration in the production of fluorine radicals, which is 0.8% is achieved. Addition of certain amounts of O2 into He/SF6 plasma results in the promotion of SF6 dissociation. Emission intensities of fluorine atoms show the maximum at the O2/SF6 ratio of 0.4.%@@ We investigate reactive fluorine atom spectroscopic characterization in atmospheric pressure of He/SF6plasma using atomic emission spectrometry.As input radio frequency (RF) power levels are raised from 140to 220 W, the emission spectra of 685.60 (3p4D→3s4P transition) and 739.87 nm (3p4P→3s4P transition)increase significantly.Moreover, an optimal value of SF6 volume concentration in the production of fluorine radicals, which is 0.8% is achieved.Addition of certain amounts of O2 into He/SF6 plasma results in the promotion of SF6 dissociation.Emission intensities of fluorine atoms show the maximum at the O2/SF6ratio of 0.4.

  11. Application of small specimens to fracture mechanics characterization of irradiated pressure vessel steels

    International Nuclear Information System (INIS)

    In this study, precracked Charpy V-notch (PCVN) specimens were used to characterize the fracture toughness of unirradiated and irradiated reactor pressure vessel steels in the transition region by means of three-point static bending. Fracture toughness at cleavage instability was calculated in terms of elastic-plastic KJc values. A statistical size correction based upon weakest-link theory was performed. The concept of a master curve was applied to analyze fracture toughness properties. Initially, size-corrected PCVN data from A 533 grade B steel, designated HSST Plate O2, were used to position the master curve and a 5% tolerance bound for KJc data. By converting PCVN data to IT compact specimen equivalent KJc data, the same master curve and 5% tolerance bound curve were plotted against the Electric Power Research Institute valid linear-elastic KJc database and the ASME lower bound KIc curve. Comparison shows that the master curve positioned by testing several PCVN specimens describes very well the massive fracture toughness database of large specimens. These results give strong support to the validity of KJc with respect to KIc in general and to the applicability of PCVN specimens to measure fracture toughness of reactor vessel steels in particular. Finally, irradiated PCVN specimens of other materials were tested, and the results are compared to compact specimen data. The current results show that PCVNs demonstrate very good capacity for fracture toughness characterization of reactor pressure vessel steels. It provides an opportunity for direct measurement of fracture toughness of irradiated materials by means of precracking and testing Charpy specimens from surveillance capsules. However, size limits based on constraint theory restrict the operational test temperature range for KJc data from PCVN specimens. 13 refs., 8 figs., 1 tab

  12. Superposition well-test method for reservoir characterization and pressure management during CO2 injection

    Science.gov (United States)

    White, J. A.

    2014-12-01

    As a significant fraction of a carbon storage project's budget is devoted to site characterization and monitoring, there has been an intense drive in recent years to both lower cost and improve the quality of data obtained. Two data streams that are cheap and always available are pressure and flow rate measurements from the injection well. Falloff testing, in which the well is shut-in for some period of time and the pressure decline curve measured, is often used to probe the storage zone and look for indications of hydraulic barriers, fracture-dominated flow, and other reservoir characteristics. These tests can be used to monitor many hydromechanical processes of interest, including hydraulic fracturing and fault reactivation. Unfortunately, the length of the shut-in period controls how far away from the injector information may be obtained. For operational reasons these tests are typically kept short and infrequent, limiting their usefulness. In this work, we present a new analysis method in which ongoing injection data is used to reconstruct an equivalent falloff test, without shutting in the well. The entire history of injection may therefore be used as a stand in for a very long test. The method relies upon a simple superposition principle to transform a multi-rate injection sequence into an equivalent single-rate process. We demonstrate the effectiveness of the method using injection data from the Snøhvit storage project. We also explore its utility in an active pressure management scenario. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  13. Characterization of pressurized hot water extracts of grape pomace: chemical and biological antioxidant activity.

    Science.gov (United States)

    Vergara-Salinas, J R; Vergara, Mauricio; Altamirano, Claudia; Gonzalez, Álvaro; Pérez-Correa, J R

    2015-03-15

    Pressurized hot water extracts obtained at different temperatures possess different compositions and antioxidant activities and, consequently, different bioactivities. We characterized two pressurized hot water extracts from grape pomace obtained at 100°C (GPE100) and 200°C (GPE200) in terms of antioxidant activity and composition, as well as protective effect on cell growth and mitochondrial membrane potential (Δψm) in a HL-60 cell culture under oxidative conditions. GPE100 extracts were richer in polyphenols and poorer in Maillard reaction products (MRPs) than were GPE200 extracts. Moreover, hydroxymethylfurfural was detected only in GPE200. Both extracts exhibited similar protective effects on cell growth (comparable to the effect of trolox). In addition, GPE100 strongly decreased the Δψm loss, reaching values even lower than those of the control culture. This protective effect may be related to its high polyphenols content. At the highest concentration assessed, both extracts showed strong cytotoxicity, especially GPE200. This cytotoxicity could be related to their MRPs content. PMID:25308643

  14. Impact of different functional crab groups on propagule recruitment and mangrove forest structure

    OpenAIRE

    Van Nedervelde, F.; U. Berger; Cannicci, S.; N. Koedam; Dahdouh-Guebas, F.

    2011-01-01

    The structure of the mangrove ecosystems is affected by various abiotic factors (temperature, salinity, nutrient availability, tidal range, topography, etc.) and biotic factors (intra and inter-specific competition, fauna, anthropogenic pressure etc.) (Lee, 1999b). Faunal impact is largely due to the crab activities (Cannicci et al., 2008). Some authors refer to ‘crabs’ as mangrove ecosystem keystone species (Smith III et al., 1991; Schories et al., 2003). They contribute actively to the fore...

  15. Characterization and Stability Evaluation of Thymoquinone Nanoemulsions Prepared by High-Pressure Homogenization

    Directory of Open Access Journals (Sweden)

    Zaki Tubesha

    2013-01-01

    Full Text Available Despite the pharmacological properties of thymoquinone (TQ, its administration in vivo remains problematic partly due to its poor water solubility, leading to low absorptivity and bioavailability. Hence, the objective of this study is to prepare, characterize, and evaluate the stability of TQ nanoemulsion (TQNE. Conventional emulsion from TQ (TQCE and empty nano- and conventional emulsions from Triolein (TRNE and TRCE are also produced for comparison purposes. The oil-in-water nanoemulsions of TQ and Triolein were produced by high-pressure homogenization. Emulsions were characterized physically by droplet size, polydispersity index, zeta potential, and refractive index. The changes of these parameters in TQNE samples stored for 6 months at 4 and 25°C were not statistically significant (P<0.05. In addition, the initial particle sizes of TQNE and TRNE were 119.6 and 119.5 nm, respectively. Stability studies were also performed for the period of 6 months. At the end of the experiment, the percent of remaining TQ in TQNE at 4, 25, and 40°C was 90.6, 89.1, and 87.4 % respectively. Slower degradation of TQ indicated the chemical stability of TQ in TQNE samples. These results indicated that TQNE is stable over a period of 6 months.

  16. Humid microclimates within the plumage of mallard ducks (Anas platyrhynchos) can potentially facilitate long distance dispersal of propagules

    Science.gov (United States)

    Coughlan, Neil E.; Kelly, Tom C.; Davenport, John; Jansen, Marcel A. K.

    2015-05-01

    Birds as carriers of propagules are major agents in the dispersal of plants, animals, fungi and microbes. However, there is a lack of empirical data in relation to bird-mediated, epizoochorous dispersal. The microclimate found within the plumage likely plays a pivotal role in survival during flight conditions. To investigate the potential of epizoochory, we have analysed the microclimatic conditions within the plumage of mallard ducks (Anas platyrhynchos). Under similar ambient conditions of humidity and temperature, a sample of mallards showed a consistent microclimatic regime with variation across the body surface. The highest (mean) temperature and specific humidity occurred between feathers of the postpatagium. The lowest humidity was found between feathers of the centre back and the lowest temperature in the crissum. Observed differences in plumage depth and density, and distance from the skin, are all likely to be determining factors of microclimate condition. Specific humidity found within the plumage was on average 1.8-3.5 times greater than ambient specific humidity. Thus, the plumage can supply a microclimate buffered from that of the exterior environment. Extrapolating survival data for Lemna minor desiccation at various temperature and humidity levels to the measured plumage microclimatic conditions of living birds, survival for up to 6 h can be anticipated, especially in crissum, crural and breast plumage. The results are discussed in the context of potential long distance epizoochorous dispersal by A. platyrhynchos and similar species.

  17. Characterization of Atmospheric Pressure Plasma Torch and the Surface Interaction for Material Removal

    Science.gov (United States)

    McWilliams, Anthony Joseph

    An atmospheric pressure plasma torch has been developed and characterized for removal of organic based coatings. The focus of the Strategic Environmental Research & Development Program (SERDP) project WP-1762, that funded the bulk of this dissertation work, is removal of paint from US Navy vessels. The goal is to develop a novel technology for coating removal that is capable of reducing the amount of environmental waste produced during the commonly used grit blasting process. The atmospheric pressure air plasma torch was identified as having the capacity to remove the paint systems while using only compressed air and electricity as a media-less removal system with drastically reduced waste generation. Any improvements to the existing technology need to be based on scientific knowledge and thus the plasma removal mechanisms or material warranted investigation. The removal of material does not show a strong relation to the plasma parameters of power, frequency, and gas flow, nor is there a strong relation to the presences of inorganic fillers impeding or altering the removal rates. The underlying removal mechanisms also do not show a strong correlation to the rotational temperature of the plasma but do show a strong correlation to the optical emission intensity. Primarily, the emission from atomic oxygen and molecular nitrogen were identified significant contributors and were investigated further. The plasma feed gas was then varied from the nitrogen and oxygen ratio present in ambient air to pure nitrogen to identify the effect of oxygen on the removal mechanism. From these experiments it was concluded that the oxygen present in air does contribute to the overall removal mechanism; however, it is not the sole contributing factor with the other major factor being nitrogen.

  18. Development and Characterization of Amorphous Nanofiber Drug Dispersions Prepared Using Pressurized Gyration.

    Science.gov (United States)

    Raimi-Abraham, Bahijja Tolulope; Mahalingam, Suntharavathanan; Davies, Philip J; Edirisinghe, Mohan; Craig, Duncan Q M

    2015-11-01

    Nanofibrous systems are attracting increasing interest as a means of drug delivery, although a significant limitation to this approach has been manufacture on a scale commensurate with dosage form production. However, recent work has suggested that nanofibers may be successfully manufactured on a suitable scale using the novel process of pressurized gyration (PG). In this study, we explore the potential of PG as a novel means of generating amorphous solid dispersions of poorly water-soluble drugs with enhanced dissolution performance. We examine the effect of increasing drug loading on fiber properties including size, surface characteristics, and the physical state of both components. Dispersions of ibuprofen in poly(vinylpyrrolidone) (PVP) were prepared (up to 50% w/w loading) and characterized using a range of imaging, thermal, diffraction, and spectroscopic techniques, while the release profiles were studied using sink and non-sink (pH 1.0) conditions. The drug was found to be dispersed on a molecular basis within the fibers; attenuated total reflection FTIR indicated evidence for a direct interaction between the drug and polymer at lower drug loading by the identification of a strong single band in the carbonyl region and amide region of ibuprofen and PVP respectively. Dissolution studies under sink conditions indicated a substantial increase in release rate, while non-sink studies showed evidence for supersaturation. It is concluded that PG presents a viable method for the production of drug-loaded nanofibers for oral administration with enhanced in vitro dissolution rate enhancement. PMID:26402331

  19. Nondestructive characterization of embrittlement in reactor pressure vessel steels -- A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    McHenry, H.I.; Alers, G.A. [National Inst. of Standards and Technology, Boulder, CO (United States). Materials Reliability Div.

    1998-03-01

    The Nuclear Regulatory Commission recently initiated a study by NIST to assess the feasibility of using physical-property measurements for evaluating radiation embrittlement in reactor pressure vessel (RPV) steels. Ultrasonic and magnetic measurements provide the most promising approaches for nondestructive characterization of RPV steels because elastic waves and magnetic fields can sense the microstructural changes that embrittle materials. The microstructural changes of particular interest are copper precipitation hardening, which is the likely cause of radiation embrittlement in RPV steels, and the loss of dislocation mobility that is an attribute of the ductile-to-brittle transition. Measurements were made on a 1% copper steel, ASTM grade A710, in the annealed, peak-aged and overaged conditions, and on an RPV steel, ASTM grade A533B. Nonlinear ultrasonic and micromagnetic techniques were the most promising measures of precipitation hardening. Ultrasonic velocity measurements and the magnetic properties associated with hysteresis-loop measurements were not particularly sensitive to either precipitation hardening or the ductile-to-brittle transition. Measurements of internal friction using trapped ultrasonic resonance modes detected energy losses due to the motion of pinned dislocations; however, the ultrasonic attenuation associated with these measurements was small compared to the attenuation caused by beam spreading that would occur in conventional ultrasonic testing of RPVs.

  20. Characterization of Atmospheric Pressure Plasma Jet (APPJ) and Its Effect on Plasmid DNA

    Science.gov (United States)

    Adhikari, Ek; Ptasinska, Sylwia

    2015-09-01

    A helium atmospheric pressure plasma jet (APPJ) source was constructed and then characterized by monitoring a deflected current on a high voltage electrode and a potential difference between two electrodes. The deflected current was also monitored for the APPJ source with varied electrical and fed gas composition e.g. admixtures of He and water vapor. The deflected power per cycle for gas admixtures was decreased with the increase in fraction of water vapor. In addition, this APPJ source was used to induce damage to aqueous plasmid DNA. The fraction of supercoiled, single-strand breaks and double-strand breaks in DNA were quantified by using agarose gel electrophoresis. The number of DNA strand breaks increased as a function of plasma irradiation time and decrease as a distance between APPJ and DNA sample increased. The APPJ with the gas admixture, in which the fraction of water vapor was varied, was also used to induce damage to aqueous DNA samples. The damage level decreased with the increase in a fraction of water vapor under specific experimental conditions. The change in numbers of DNA strand breaks irradiated by a pure He plasma and a plasma with a gas admixture is predicted by different physical and chemical process in the APPJ. This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences under Award Number DE-FC02-04ER15533.

  1. Irradiation Induced Defect Characterization in Reactor Pressure Vessel Steel by Small Angle Neutron Scattering

    Science.gov (United States)

    Han, Yougn-Soo; Shin, Eun-Joo; Lee, Chang-Hee; Park, Duck-Gun

    The degradation of the mechanical properties of the RPV (Reactor Pressure Vessel) steel during an irradiation in a nuclear power plant is closely related to the irradiation induced defects. The size of these defects is known to be a few nanometer, and the small angle neutron scattering technique is regarded as the best non destructive technique to characterize the nano sized inhomogeneities in bulk samples. The investigated the RPV steel has been used in YeongKwang nuclear power plant at Korea and the Cu content of the RPV steel is 0.06 wt%. The RPV steel was irradiated in the HANARO reactor at KAERI. The small angle neutron scattering experiments were performed by the SANS instrument in the HANARO reactor. The nano sized irradiation induced defects were quantitatively analyzed by SANS and the type of the irradiation induced defects was discussed in detail. The relation between irradiation induced defects and the yield strength was investigated. The characteristics of irradiation induced defects in low Cu containing RPV steel were discussed.

  2. Laser-Ionization TOF Mass Spectrometer Characterization of Benzene Destruction in Atmospheric Pressure Pulsed Discharge

    Institute of Scientific and Technical Information of China (English)

    LIU Jiahong; XIAO Qingmei; WANG Liping; YAO Zhi; DING Hongbin

    2009-01-01

    Benzene is.a major industrial air pollutant and can cause serious human health disorders. In this paper an investigation on benzene destruction, in an atmospheric-pressure fast-flow pulsed DC-discharge by means of laser ionization combined with time-of-flight (TOF) mass spectrometry, is reported. Most by-products including transient reactive species from the benzene discharge were characterized by molecular beam sampling combined with TOF mass spectrometry.It is showed that, with a gas mixture of 0.5% C6H6 in Ar, benzene can be effectively destroyed by discharge plasma. The intermediate species consisted of small fragments of CNHm (n=3~5,m =1~11), cycle-chain species of CNHm (n=6~9, m = 7~10) and polycyclic species CNHm (n ≥9,m = 8~12). The alternation of mass peaks (intensity) with even/odd electrons was observed in the measured mass spectra. The results indicated that the alternation is mainly due to the different ionization potentials of the open shell and close shell species. Based on the examination of the features of the species' composition, the primary reaction pathways are proposed and discussed.

  3. Evaluation of four non-invasive methods for examination and characterization of pressure ulcers

    DEFF Research Database (Denmark)

    Andersen, E.S.; Karlsmark, T.

    2008-01-01

    , we here report on usability of four non-invasive techniques for evaluation of pressure ulcers. Methods: Fifteen pressure ulcers in stage 0-IV were examined using four different non-invasive techniques [redness index, skin temperature, skin elasticity (i.e. retraction time), and ultrasound scanning...... at all pressure ulcers, but none at the reference points. The skin retraction time was often higher at the location of a pressure ulcer than at the reference location. We found no correlation between the stage of the ulcers and temperature, redness index, subepidermal layer thickness, or retraction...

  4. Development and characterization of a pressure-sensitive luminescent coating based on Pt(II)-porphyrin self-assembled monolayers

    Science.gov (United States)

    Sakamura, Y.; Suzuki, T.; Kawabata, S.

    2015-06-01

    A pressure-sensitive luminescent coating (PSLC) applicable to the visualization of pressure distributions in micro-scale flow devices was developed. Pt(II)-porphyrin was synthesized and covalently attached to the surface of indium tin oxide (ITO) glass plates by a self-assembled monolayer (SAM) process. The UV-visible absorption spectrum, pressure and temperature sensitivities and photostability of the PSLC were then measured to characterize the developed PSLC. It was found that (a) the chemisorption of the porphyrin did not greatly perturb the molecular orbitals of the porphyrin responsible for its photophysics, (b) the pressure dependency of the luminescent intensity of the PSLC obeyed a power function curve and the pressure sensitivities at 273, 293, 313 and 333 K were obtained in the pressure range from 5 to 120 kPa, (c) the luminescent intensity of the PSLC almost linearly decreased with temperature and the temperature sensitivities at 5, 40, 100 and 120 kPa evaluated in the temperature range from 273 to 333 K were -0.67, -0.72, -0.75 and -0.78%/K, respectively and (d) the decrease in the luminescent intensity of the PSLC after a 30 min exposure to an excitation light was 1.23% of its initial intensity and much smaller than that of Pt(II)-porphyrin absorbed on a TLC (thin-layer chromatography) sheet.

  5. Characterization and calibration of the central arterial pressure waveform obtained from vibrocardiographic signal

    Science.gov (United States)

    Casacanditella, L.; Cosoli, G.; Casaccia, S.; Rohrbaugh, J. W.; Scalise, L.; Tomasini, E. P.

    2016-06-01

    Laser Doppler Vibrometry (LDV) has been demonstrated to be a non-contact technique with high sensitivity, able to measure the skin vibrations related to cardiac activity. The obtainable mechanical signal (i.e. a velocity signal), VibroCardioGram (VCG), is able to provide significant physiological parameters, such as Heart Rate (HR). In this work, the authors aim to present a non-contact measurement method to obtain the arterial blood pressure signal from the mechanical vibrations assessed by LDV, in a central district of the arterial tree, such as carotid artery. In fact, in this way it is possible to indirectly assess Central Arterial Blood Pressure (CABP), which indicates the hemodynamic load on the heart, so that it is considered an important index predicting the cardiac risk of a subject. The measurement setup involves the use of an oscillometric cuff, to measure peripheral blood pressure at the radial artery level. Diastolic and Mean Arterial Pressure (MAP) at radial level were used to calibrate the integrated LDV signal (i.e. a displacement signal). As regard calibration, an exponential mathematical model was adopted to derive the pressure waveform from the displacement of the vessel detected by LDV. Results show an average difference of around 20% between systolic pressure measured at brachial level (i.e. peripheral pressure value) and systolic pressure derived from VCG signal measured over the carotid artery (i.e. central pressure). This is a physiological difference, consistent with the literature about the physiological increase of Systolic Blood Pressure (SBP) and Pressure Pulse (PP) at increased distances from the heart. However, this non-contact technique is affected by movement artifacts and by reflection phenomena not related to the studied vessel and so it is necessary to account of such issues in the results.

  6. Bulk characterization of pharmaceutical powders by low-pressure compression II

    DEFF Research Database (Denmark)

    Hagsten Sørensen, A.; Sonnergaard, Jørn; Hovgaard, L.

    2006-01-01

    The aim of the present study was to investigate the effect of punch and die diameter, sample size, compression speed, and particle size on two low-pressure compression-derived parameters; the compressed density and the Walker w parameter. The excellent repeatability of the low-pressure compressio...

  7. Intercomparison of techniques for inspection and diagnostics of heavy water reactor pressure tubes. Determination of hydrogen concentration and blister characterization

    International Nuclear Information System (INIS)

    Heavy water reactors (HWRs) comprise significant numbers of today's operating nuclear power plants, and more are under construction. Efficient and accurate inspection and diagnostic techniques for various reactor components and systems, especially pressure tubes, are an important factor in ensuring reliable and safe plant operation. To foster international collaboration in the efficient and safe use of nuclear power, the IAEA conducted a Coordinated Research Project (CRP) on Intercomparison of Techniques for HWR Pressure Tube Inspection and Diagnostics. This CRP was carried out within the framework of the IAEA's Technical Working Group on Advanced Technologies for HWRs (the TWG-HWR). The TWG-HWR is a group of experts nominated by their governments and designated by the IAEA to provide advice and to support implementation of IAEA's project on advanced technologies for HWRs. The objective of the CRP was to compare non-destructive inspection and diagnostic techniques, in use and being developed, for structural integrity assessment of HWR pressure tubes. During the first phase of this CRP participants investigated the capability of different techniques to detect and characterize flaws. During the second phase participants collaborated to detect and characterize hydride blisters and to determine the hydrogen concentration in zirconium alloys. The intention was to identify the most effective pressure tube inspection and diagnostic methods and to identify further development needs. The organizations which participated in phase 2 of this CRP are: - Comision Nacional de Energia Atomica (CNEA), Argentina; - Atomic Energy of Canada Ltd. (AECL), Chalk River Laboratories (CRL), Canada; - Bhabha Atomic Research Centre (BARC), India; - Korea Atomic Energy Research Institute (KAERI), Republic of Korea; - National Institute for Research and Development for Technical Physics (NIRDTP), Romania; - Nuclear Non-Destructive Testing Research and Services (NNDT), Romania. IAEA-TECDOC-1499

  8. Characterization of the physicochemical properties of phospholipid vesicles prepared in CO2/water systems at high pressure.

    Science.gov (United States)

    Nakamura, Hidemi; Taguchi, Shogo; Suga, Keishi; Hayashi, Keita; Jung, Ho-Sup; Umakoshi, Hiroshi

    2015-01-01

    Phospholipid vesicles were prepared by the nonsolvent method using high-pressure CO2/water systems. The membrane properties of vesicles prepared at different pressures and temperatures were mainly characterized based on analysis of the membrane fluidity and membrane polarity, using the fluorescent probes 1,6-diphenyl-1,3,5-hexatriene and 6-dodecanoyl-N,N-dimethyl-2-naphthylamine, respectively. The CO2(liquid)/water(liquid) and the CO2(supercritical)/water(liquid) two-phase (heterogeneous) systems resulted in the formation of vesicles with high yield (ca. 85%-88%). The membrane fluidity and polarity of the vesicles were similar to those of liposomes prepared by the conventional method. It is suggested that high-pressure CO2 can be used to form an appropriate hydrophobic-hydrophilic interface where phospholipid molecules as a self-assembled membrane. PMID:26296356

  9. Characterization of Zebrafish Green Cone Photoresponse Recorded with Pressure-Polished Patch Pipettes, Yielding Efficient Intracellular Dialysis

    OpenAIRE

    Aquila, Marco; Benedusi, Mascia; Fasoli, Anna; Rispoli, Giorgio

    2015-01-01

    The phototransduction enzymatic cascade in cones is less understood than in rods, and the zebrafish is an ideal model with which to investigate vertebrate and human vision. Therefore, here, for the first time, the zebrafish green cone photoresponse is characterized also to obtain a firm basis for evaluating how it is modulated by exogenous molecules. To this aim, a powerful method was developed to obtain long-lasting recordings with low access resistance, employing pressure-polished patch pip...

  10. Observation and characterization of flow in critical sections of a horizontal pressurized gating system using water models

    OpenAIRE

    Jaiganesh Venkataramani; Prakasan Kalakkath

    2013-01-01

    This work is concerned with the hydraulics and flow characterization in a pressurized, horizontal gating system with multiple ingates attached to a plate mold, using transparent water models. Runners with two different aspect ratios (w/h = 0.5 and 2) and four different types of ingates (rectangular, convergent, divergent and venturi) were examined for their influence on flow behavior. Flow behavior was visualized using a high speed camera capable of capturing images up to 10,000 frames per se...

  11. Blueberry polyphenol oxidase: Characterization and the kinetics of thermal and high pressure activation and inactivation.

    Science.gov (United States)

    Terefe, Netsanet Shiferaw; Delon, Antoine; Buckow, Roman; Versteeg, Cornelis

    2015-12-01

    Partially purified blueberry polyphenol oxidase (PPO) in Mcllvaine buffer (pH=3.6, typical pH of blueberry juice) was subjected to processing at isothermal-isobaric conditions at temperatures from 30 to 80 °C and pressure from 0.1 to 700 MPa. High pressure processing at 30-50 °C at all pressures studied caused irreversible PPO activity increase with a maximum of 6.1 fold increase at 500 MPa and 30 °C. Treatments at mild pressure-mild temperature conditions (0.1-400 MPa, 60 °C) also caused up to 3 fold PPO activity increase. Initial activity increase followed by a decrease occurred at relatively high pressure-mild temperature (400-600 MPa, 60 °C) and mild pressure-high temperature (0.1-400 MPa, 70-80 °C) combinations. At temperatures higher than 76 °C, monotonic decrease in PPO activity occurred at 0.1 MPa and pressures higher than 500 MPa. The activation/inactivation kinetics of the enzyme was successfully modelled assuming consecutive reactions in series with activation followed by inactivation. PMID:26041182

  12. High-Pressure Torsion of Ti: Synchrotron characterization of phase volume fraction and domain sizes

    Science.gov (United States)

    Bolmaro, Raúl E.; Sordi, Vitor L.; Ferrante, Maurizio; Brokmeier, Heinz-Günter; Kawasaki, Megumi; Langdon, Terence G.

    2014-08-01

    Rods of grade 2 Ti were processed by Equal-Channel Angular Pressing (ECAP) (phi = 120° at 573 K) employing 2, 4 and 6 passes. The same billets were further deformed by High- Pressure Torsion (HPT) at room temperature, varying both the hydrostatic pressure (1 and 6 GPa) and the number of rotations (n = 1 and 5). The ECAP and HPT samples were studied by synchrotron radiation at DESY-Petra III GEMS line. On the ECAP samples, textures were thus determined while for both ECAP and HPT samples the measurements were further analyzed by MAUD. Domain sizes and phase volume fractions were determined as a function of the radial direction of the samples. Alpha and Omega phases were detected in different amounts depending mostly on hydrostatic pressure and shear deformation. These transition phases can be pressure-induced during HPT processing and the results of Vickers microhardness measurements were related to the processing parameters and to the amounts of these phases.

  13. Arterial pulse pressure amplification described by means of a nonlinear wave model: characterization of human aging

    Science.gov (United States)

    Alfonso, M.; Cymberknop, L.; Armentano, R.; Pessana, F.; Wray, S.; Legnani, W.

    2016-04-01

    The representation of blood pressure pulse as a combination of solitons captures many of the phenomena observed during its propagation along the systemic circulation. The aim of this work is to analyze the applicability of a compartmental model for propagation regarding the pressure pulse amplification associated with arterial aging. The model was applied to blood pressure waveforms that were synthesized using solitons, and then validated by waveforms obtained from individuals from differentiated age groups. Morphological changes were verified in the blood pressure waveform as a consequence of the aging process (i.e. due to the increase in arterial stiffness). These changes are the result of both a nonlinear interaction and the phenomena present in the propagation of nonlinear mechanic waves.

  14. Characterization of Thick and Thin Film SiCN for Pressure Sensing at High Temperatures

    OpenAIRE

    Rama B. Bhat; Ion Stiharu; Sergey Andronenko; Alfin Leo

    2010-01-01

    Pressure measurement in high temperature environments is important in many applications to provide valuable information for performance studies. Information on pressure patterns is highly desirable for improving performance, condition monitoring and accurate prediction of the remaining life of systems that operate in extremely high temperature environments, such as gas turbine engines. A number of technologies have been recently investigated, however these technologies target specific applica...

  15. Characterization of magnetically impelled arc butt welded T11 tubes for high pressure applications

    OpenAIRE

    R. Sivasankari; V. Balusamy; P.R. Venkateswaran; G. Buvanashekaran; K Ganesh Kumar

    2015-01-01

    Magnetically impelled arc butt (MIAB) welding is a pressure welding process used for joining of pipes and tubes with an external magnetic field affecting arc rotation along the tube circumference. In this work, MIAB welding of low alloy steel (T11) tubes were carried out to study the microstructural changes occurring in thermo-mechanically affected zone (TMAZ). To qualify the process for the welding applications where pressure could be up to 300 bar, the MIAB welds are studied with variations...

  16. Characterization of base pressure fluctuations in a blunt trailing edge wake with three-dimensional forcing

    Science.gov (United States)

    Clark, Heather; Lavoie, Philippe

    2015-11-01

    The wakes of many nominally two-dimensional bluff bodies exhibit multiple intrinsic three-dimensional instabilities whose spatiotemporal structure and growth rate depend on geometry and Reynolds number. Here, these features are investigated experimentally for a blunt trailing edge profiled body using simultaneous measurements of velocity and fluctuating surface pressure on the model rear face near separation. Passive three-dimensional forcing of the wake is implemented with an array of vortex generators that are distributed according to the characteristic spanwise wavelength of the dominant secondary instability. For a Reynolds number of 8000 based on model thickness, the control strategy is found to increase the base pressure coefficient by 26% while globally reducing the amplitude of base pressure fluctuations, relative to the unforced flow. Additionally, amplitude modulation of the pressure signals that is observed in the natural wake decreases in strength with distributed forcing as a result of the modified three-dimensional flow structure. The spanwise distribution of pressure will be further examined for the baseline and controlled flows via temporal spectral analysis and spatial modal decomposition.

  17. Characterization and Optimization of Polymer-Ceramic Pressure-Sensitive Paint by Controlling Polymer Content

    Directory of Open Access Journals (Sweden)

    Hitoshi Ishikawa

    2011-07-01

    Full Text Available A pressure-sensitive paint (PSP with fast response characteristics that can be sprayed on a test article is studied. This PSP consists of a polymer for spraying and a porous particle for providing the fast response. We controlled the polymer content (% from 10 to 90% to study its effects on PSP characteristics: the signal level, pressure sensitivity, temperature dependency, and time response. The signal level and temperature dependency shows a peak in the polymer content around 50 to 70%. The pressure sensitivity was fairly constant in the range between 0.8 and 0.9 %/kPa. The time response is improved by lowering the polymer content. The variation of the time response is shown to be on the order of milliseconds to ten seconds. A weight coefficient is introduced to optimize the resultant PSPs. By setting the weight coefficient, we can optimize the PSP for sensing purposes.

  18. Heavy section steel technology program technical report No. 38. Fracture toughness characterization of HSST intermediate pressure vessel material

    International Nuclear Information System (INIS)

    The primary objective of the Heavy Section Steel Technology (HSST) Program is to develop pertinent fracture technology to demonstrate the structural reliability of present and contemplated water-cooled nuclear reactor pressure vessels. In order to demonstrate the ability to predict failure of large, heavy-walled pressure vessels under service type loading conditions, the fracture toughness properties of the vessel's materials must be characterized. The sampling procedure and test results are presented for vessel material supplied by the Oak Ridge National Laboratory that were used to characterize the fracture toughness of the HSST Intermediate Test Vessels. The metallurgical condition and heat treatment of the test material was representative of the vessel simulated service test condition. Test specimen locations and orientations were selected by the Oak Ridge National Laboratory and are representative of flaw orientations incorporated in the test vessels. The fracture toughness is documented for the materials from each of the eight HSST Intermediate Pressure Vessels tested to date. 7 references. (U.S.)

  19. Pulse rise-time characterization of a high pressure xenon gamma detector for use in resolution enhancement

    International Nuclear Information System (INIS)

    High pressure xenon ionization chamber detectors are possible alternatives to traditional thallium doped sodium iodine [NaI(Tl)] and hyperpure germanium as gamma-spectrometers in certain applications. Xenon detectors incorporating a Frisch grid exhibit energy resolutions comparable to cadmium/zinc/telluride (CZT) (e.g., 2% a 662 keV) but with far greater sensitive volumes. The Frisch grid reduces the position dependence of the anode pulse rise-times, but it also increases the detector vibration sensitivity, anode capacitance, voltage requirements and mechanical complexity. Possibility of eliminating the grid electrode in high-pressure xenon detectors and preserving the high energy resolution using electronic rise-time compensation methods have been investigated. A two-electrode cylindrical high pressure xenon gamma-detector coupled to time-to-amplitude conversion electronics was used to characterize the pulse rise-time of deposited gamma-photons. Time discrimination was used to characterize the pulse rise-time versus photo peak position and resolution. These data were collected to investigate the effect of pulse rise-time compensation on resolution and efficiency. (author)

  20. Novel approaches in advanced combustion characterization of fuels for advanced pressurized combustion

    Energy Technology Data Exchange (ETDEWEB)

    Aho, M.; Haemaelaeinen, J. [VTT Energy (Finland); Joutsenoja, T. [Tampere Univ. of Technology (Finland)

    1996-12-01

    This project is a part of the EU Joule 2 (extension) programme. The objective of the research of Technical Research Centre of Finland (VTT) is to produce experimental results of the effects of pressure and other important parameters on the combustion of pulverized coals and their char derivates. The results can be utilized in modelling of pressurized combustion and in planning pilot-scale reactors. The coals to be studied are Polish hvb coal, French lignite (Gardanne), German anthracite (Niederberg) and German (Goettelbom) hvb coal. The samples are combusted in an electrically heated, pressurized entrained flow reactor (PEFR), where the experimental conditions are controlled with a high precision. The particle size of the fuel can vary between 100 and 300 {mu}m. The studied things are combustion rates, temperatures and sizes of burning single coal and char particles. The latter measurements are performed with a method developed by Tampere University of Technology, Finland. In some of the experiments, mass loss and elemental composition of the char residue are studied in more details as the function of time to find out the combustion mechanism. Combustion rate of pulverized (140-180 {mu}m) Gardanne lignite and Niederberg anthracite were measured and compared with the data obtained earlier with Polish hvb coal at various pressures, gas temperatures, oxygen partial pressures and partial pressures of carbon dioxide in the second working period. In addition, particle temperatures were measured with anthracite. The experimental results were treated with multivariable partial least squares (PLS) method to find regression equation between the measured things and the experimental variables. (author)

  1. Experimental characterization of an argon laminar plasma jet at atmospheric pressure

    International Nuclear Information System (INIS)

    This paper deals with a dc laminar pure argon plasma jet operating at atmospheric pressure in ambient air that was experimentally studied in order to obtain temperature and velocity. Plasma jet temperature was evaluated by optical emission spectroscopy and the plasma jet velocity was determined by various methods using a pressure sensor. It is shown that the maximum plasma jet temperature is 15 000 K and the maximum plasma jet velocity is 250 m s-1 at the plasma jet centre. Finally, a study of the ambient air amount entrained into the plasma jet is presented.

  2. Experimental characterization of an argon laminar plasma jet at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Langlois-Bertrand, Emilie; De Izarra, Charles, E-mail: charles.de_izarra@univ-orleans.fr [Groupe de Recherche sur l' Energetique des Milieux Ionises, UMR6606 Universite d' Orleans - CNRS, Faculte des Sciences, Site de Bourges, rue Gaston Berger, BP 4043, 18028 BOURGES Cedex (France)

    2011-10-19

    This paper deals with a dc laminar pure argon plasma jet operating at atmospheric pressure in ambient air that was experimentally studied in order to obtain temperature and velocity. Plasma jet temperature was evaluated by optical emission spectroscopy and the plasma jet velocity was determined by various methods using a pressure sensor. It is shown that the maximum plasma jet temperature is 15 000 K and the maximum plasma jet velocity is 250 m s{sup -1} at the plasma jet centre. Finally, a study of the ambient air amount entrained into the plasma jet is presented.

  3. High-Pressure Torsion of Ti: Synchrotron characterization of phase volume fraction and domain sizes

    OpenAIRE

    Bolmaro, Raúl E; Sordi, Vitor L.; Ferrante, Maurizio; Brokmeier, Heinz-Günter; Kawasaki, Megumi; Terence G. Langdon

    2014-01-01

    Rods of grade 2 Ti were processed by Equal-Channel Angular Pressing (ECAP) (phi = 120° at 573 K) employing 2, 4 and 6 passes. The same billets were further deformed by High- Pressure Torsion (HPT) at room temperature, varying both the hydrostatic pressure (1 and 6 GPa) and the number of rotations (n = 1 and 5). The ECAP and HPT samples were studied by synchrotron radiation at DESY-Petra III GEMS line. On the ECAP samples, textures were thus determined while for both ECAP and HPT samples the m...

  4. Experimental and numerical characterization of the sound pressure in standing wave acoustic levitators

    Science.gov (United States)

    Stindt, A.; Andrade, M. A. B.; Albrecht, M.; Adamowski, J. C.; Panne, U.; Riedel, J.

    2014-01-01

    A novel method for predictions of the sound pressure distribution in acoustic levitators is based on a matrix representation of the Rayleigh integral. This method allows for a fast calculation of the acoustic field within the resonator. To make sure that the underlying assumptions and simplifications are justified, this approach was tested by a direct comparison to experimental data. The experimental sound pressure distributions were recorded by high spatially resolved frequency selective microphone scanning. To emphasize the general applicability of the two approaches, the comparative studies were conducted for four different resonator geometries. In all cases, the results show an excellent agreement, demonstrating the accuracy of the matrix method.

  5. G-Tunnel pressurized slot-testing preparations; Yucca Mountain Site Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, R.M.; Sifre-Soto, C. [Sandia National Labs., Albuquerque, NM (United States); Mann, K.L.; Bellman, R.A. Jr.; Luker, S. [Science Applications International Corp., Las Vegas, NV (United States); Dodds, D.J. [North Pacific Research, Portland, OR (United States)

    1992-04-01

    Designers and analysts of radioactive waste repositories must be able to predict the mechanical behavior of the host rock. Sandia National laboratories elected to conduct a development program on pressurized slot testing and featured (1) development of an improved method to cut slots using a chain saw with diamond-tipped cutters, (2) measurements useful for determining in situ stresses normal to slots, (3) measurements applicable for determining the in situ modulus of deformation parallel to a drift surface, and (4) evaluations of the potentials of pressurized slot strength testing. This report describes the preparations leading to the measurements and evaluations.

  6. Characterization of pyrogenic black carbon by desorption atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Podgorski, David C; Hamdan, Rasha; McKenna, Amy M; Nyadong, Leonard; Rodgers, Ryan P; Marshall, Alan G; Cooper, William T

    2012-02-01

    We present a new method for molecular characterization of intact biochar directly, without sample preparation or pretreatment, on the basis of desorption atmospheric pressure photoionization (DAPPI) coupled to Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. Conventional ionization methods (e.g., electrospray or atmospheric pressure photoionization) for characterization of natural organic matter have limited utility for the characterization of chars due to incomplete solubility in common solvents. Therefore, direct ionization techniques that do not require sample dissolution prior to analysis are ideal. Here, we apply DAPPI FTICR mass spectrometry to enable the first molecular characterization of uncharred parent oak biomass and after combustion (250 °C) or pyrolysis (400 °C). Parent oak is primarily composed of cellulose-, lignin-, and resin-like compounds. Oak combusted at 250 °C contains condensed aromatic compounds with low H/C and O/C ratios while retaining compounds with high H/C and O/C ratios. The bimodal distribution of aromatic and aliphatic compounds observed in the combusted oak sample is attributed to incomplete thermal degradation of lignin and hemicellulose. Pyrolyzed oak constituents exhibit lower H/C and O/C ratios: approximately three-quarters of the identified species are aromatic. DAPPI FTICR MS results agree with bulk elemental composition as well as functional group distributions determined by elemental analysis and solid state (13)C NMR spectroscopy. Complete molecular characterization of biomass upon thermal transformation may provide insight into the biogeochemical cycles of biochar and future renewable energy sources, particularly for samples currently limited by solubility, separation, and sample preparation. PMID:22242739

  7. Characterization of magnetically impelled arc butt welded T11 tubes for high pressure applications

    Directory of Open Access Journals (Sweden)

    R. Sivasankari

    2015-09-01

    Full Text Available Magnetically impelled arc butt (MIAB welding is a pressure welding process used for joining of pipes and tubes with an external magnetic field affecting arc rotation along the tube circumference. In this work, MIAB welding of low alloy steel (T11 tubes were carried out to study the microstructural changes occurring in thermo-mechanically affected zone (TMAZ. To qualify the process for the welding applications where pressure could be up to 300 bar, the MIAB welds are studied with variations of arc current and arc rotation time. It is found that TMAZ shows higher hardness than that in base metal and displays higher weld tensile strength and ductility due to bainitic transformation. The effect of arc current on the weld interface is also detailed and is found to be defect free at higher values of arc currents. The results reveal that MIAB welded samples exhibits good structural property correlation for high pressure applications with an added benefit of enhanced productivity at lower cost. The study will enable the use of MIAB welding for high pressure applications in power and defence sectors.

  8. Characterization of typical chemical background interferences in atmospheric pressure ionization liquid chromatography-mass spectrometry

    NARCIS (Netherlands)

    Guo, Xinghua; Bruins, Andries P.; Covey, Thomas R.

    2006-01-01

    The structures and origins of typical chemical background noise ions in positive atmospheric pressure ionization liquid chromatography/mass spectrometry (API LC/MS) are investigated and summarized in this study. This was done by classifying chemical background ions using precursor and product ion sc

  9. System overview and characterization of a high-temperature, high-pressure, entrained-flow, laboratory-scale gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, Madison A.; Dreyer, Christopher B.; Parker, Terence E.; Porter, Jason M., E-mail: jporter@mines.edu [Department of Mechanical Engineering, Colorado School of Mines, Golden, Colorado 80401 (United States); Jakulewicz, Micah S. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2015-05-15

    The high-temperature, high-pressure, entrained-flow, laboratory-scale gasifier at the Colorado School of Mines, including the primary systems and the supporting subsystems, is presented. The gasifier is capable of operating at temperatures and pressures up to 1650 °C and 40 bar. The heated section of the reactor column has an inner diameter of 50 mm and is 1 m long. Solid organic feedstock (e.g., coal, biomass, and solid waste) is ground into batches with particle sizes ranging from 25 to 90 μm and is delivered to the reactor at feed rates of 2–20 g/min. The maximum useful power output of the syngas is 10 kW, with a nominal power output of 1.2 kW. The initial characterization and demonstration results of the gasifier system with a coal feedstock are also reported.

  10. Dosimetry experiment 'Dompac'. Neutronic simulation of the thickness of a PWR pressure vessel. Irradiation damage characterization

    International Nuclear Information System (INIS)

    For suitable extrapolation of irradiated PWR ferritic steel results, proper irradiation of the pressure vessel has been 'simulated' in test reactor. For this purpose, a huge steel block (20 cm in depth) was loaded with Saclay's graphite (GAMIN) and tungsten damage detectors. Core-block water gap was optimized through spectrum indexes method, by ANISN and SABINE codes so that spectrum in 1/4 thickness matches with ANISN computations for PWR Fessenheim 1. A good experimental agreement is found with calculated dpa damage gradient. 3D Monte Carlo computation (TRIPOLI) was performed on the DOMPAC device, and spectrum indexes evolution was found consistent with experimental results. Surveillance rigs behind a 'thermal shield' were also simulated, including damage and activation monitors. Dosimetry results give an order of magnitude of accuracies involved in projecting steel sample embrittlement to the pressure vessel

  11. Fabrication and characterization of Si3N4 ceramics without additives by high pressure hot pressing

    Science.gov (United States)

    Shimada, M.; Tanaka, A.; Yamada, T.; Koizumi, M.

    1984-01-01

    High pressure hot-pressing of Si3N4 without additives was performed using various kinds of Si3N4 powder as starting materials, and the relation between densification and alpha-beta phase transformation was studied. The temperature dependences of Vickers microhardness and fracture toughness were also examined. Densification of Si3N4 was divided into three stages, and it was found that densification and phase transformation of Si3N4 under pressure were closely associated. The results of the temperature dependence of Vickers microhardness indicated that the high-temperature hardness was strongly influenced not only by the density and microstructure of sintered body but also by the purity of starting powder. The fracture toughness values of Si3N4 bodies without additives were 3.29-4.39 MN/m to the 3/2 power and independent of temperature up to 1400 C.

  12. Characterization of an atmospheric pressure air plasma source for polymer surface modification

    Science.gov (United States)

    Yang, Shujun; Tang, Jiansheng

    2013-10-01

    An atmospheric pressure air plasma source was generated through dielectric barrier discharge (DBD). It was used to modify polyethyleneterephthalate (PET) surfaces with very high throughput. An equivalent circuit model was used to calculate the peak average electron density. The emission spectrum from the plasma was taken and the main peaks in the spectrum were identified. The ozone density in the down plasma region was estimated by Absorption Spectroscopy. NSF and ARC-ODU

  13. Characterization of Thick and Thin Film SiCN for Pressure Sensing at High Temperatures

    Directory of Open Access Journals (Sweden)

    Rama B. Bhat

    2010-02-01

    Full Text Available Pressure measurement in high temperature environments is important in many applications to provide valuable information for performance studies. Information on pressure patterns is highly desirable for improving performance, condition monitoring and accurate prediction of the remaining life of systems that operate in extremely high temperature environments, such as gas turbine engines. A number of technologies have been recently investigated, however these technologies target specific applications and they are limited by the maximum operating temperature. Thick and thin films of SiCN can withstand high temperatures. SiCN is a polymer-derived ceramic with liquid phase polymer as its starting material. This provides the advantage that it can be molded to any shape. CERASET™ also yields itself for photolithography, with the addition of photo initiator 2, 2-Dimethoxy-2-phenyl-acetophenone (DMPA, thereby enabling photolithographical patterning of the pre-ceramic polymer using UV lithography. SiCN fabrication includes thermosetting, crosslinking and pyrolysis. The technology is still under investigation for stability and improved performance. This work presents the preparation of SiCN films to be used as the body of a sensor for pressure measurements in high temperature environments. The sensor employs the phenomenon of drag effect. The pressure sensor consists of a slender sensitive element and a thick blocking element. The dimensions and thickness of the films depend on the intended application of the sensors. Fabrication methods of SiCN ceramics both as thin (about 40–60 µm and thick (about 2–3 mm films for high temperature applications are discussed. In addition, the influence of thermosetting and annealing processes on mechanical properties is investigated.

  14. Characterization of transient discharges under atmospheric pressure conditions applying nitrogen photoemission and current measurements

    OpenAIRE

    Keller, Sandra; Rajasekaran, Priyadarshini; Bibinov, Nikita; Awakowicz, Peter

    2011-01-01

    The plasma parameters such as electron distribution function and electron density of three atmospheric-pressure transient discharges namely filamentary and homogeneous dielectric barrier discharges in air, and the spark discharge of argon plasma coagulation (APC) system are determined. A combination of numerical simulation as well as diagnostic methods including current measurement and optical emission spectroscopy (OES) based on nitrogen emissions is used. The applied methods supplement each...

  15. RF Modelling and Characterization of Tyre Pressure Sensors and Vehicle Access Systems

    OpenAIRE

    Brzeska, Malgorzata Dominika

    2015-01-01

    Core topics of the work are the vehicle access systems such as PAssive Start and Entry (PASE), Remote Keyless Entry (RKE) as well as Tyre Pressure Monitoring System (TPMS). Two goals are followed: the development of antennas and functionality analysis from RF (Radio Frequency) point of view and improvement of system parts. The overall objective of this work is to advance the state-of-the-art vehicular electromagnetic simulation taking into account the vehicle body and nearest surroundings.

  16. Sublimation characterization and vapor pressure estimation of an HIV nonnucleoside reverse transcriptase inhibitor using thermogravimetric analysis.

    Science.gov (United States)

    Xie, Minli; Ziemba, Theresa M; Maurin, Michael B

    2003-01-01

    The purpose of this research is to investigate the sublimation process of DPC 963, a second-generation nonnucleoside reverse transcriptase inhibitor for HIV-1 retrovirus, and to better understand the effect of sublimation during active pharmaceutical ingredient (API) manufacture and formulation development, especially the drying processes. Sublimation of DPC 963 at 150 degrees C and above was determined by thermogravimetric analysis-Fourier transform infrared (TGA-FTIR). The rates of sublimation at different temperatures were measured using isothermal TGA. Condensed material was collected and analyzed by differential scanning calorimetry (DSC), x-ray powder diffraction (XRPD), and infrared (IR) spectrometry. Benzoic acid was used as a reference standard to derive a linear logarithmic relationship between sublimation/evaporation rate and vapor pressure specific to the TGA system used in this study. Sublimation and evaporation of DPC 963 were found to follow apparent zero-order kinetics. Using the Eyring equation, the enthalpy and entropy of the sublimation and evaporation processes were obtained. The enthalpies of sublimation and evaporation were found to be 29 and 22 kcal/mol, respectively. The condensed material from the vapor phase was found to exist in 2 physical forms, amorphous and crystalline. Using benzoic acid as a reference standard, vapor pressure of DPC 963 at different temperatures was calculated using the linear logarithmic relationship obtained. DPC 963 undergoes sublimation at appreciable rates at 150 degrees C and above but this is not likely to pose a serious issue during the manufacturing process. Vapor pressure estimation using thermogravimetric analysis provided sufficient accuracy to be used as a fast, simple, and safe alternative to the traditional methods of vapor pressure determination. PMID:12916905

  17. Characterization of thick and thin film SiCN for pressure sensing at high temperatures.

    Science.gov (United States)

    Leo, Alfin; Andronenko, Sergey; Stiharu, Ion; Bhat, Rama B

    2010-01-01

    Pressure measurement in high temperature environments is important in many applications to provide valuable information for performance studies. Information on pressure patterns is highly desirable for improving performance, condition monitoring and accurate prediction of the remaining life of systems that operate in extremely high temperature environments, such as gas turbine engines. A number of technologies have been recently investigated, however these technologies target specific applications and they are limited by the maximum operating temperature. Thick and thin films of SiCN can withstand high temperatures. SiCN is a polymer-derived ceramic with liquid phase polymer as its starting material. This provides the advantage that it can be molded to any shape. CERASET™ also yields itself for photolithography, with the addition of photo initiator 2, 2-Dimethoxy-2-phenyl-acetophenone (DMPA), thereby enabling photolithographical patterning of the pre-ceramic polymer using UV lithography. SiCN fabrication includes thermosetting, crosslinking and pyrolysis. The technology is still under investigation for stability and improved performance. This work presents the preparation of SiCN films to be used as the body of a sensor for pressure measurements in high temperature environments. The sensor employs the phenomenon of drag effect. The pressure sensor consists of a slender sensitive element and a thick blocking element. The dimensions and thickness of the films depend on the intended application of the sensors. Fabrication methods of SiCN ceramics both as thin (about 40-60 μm) and thick (about 2-3 mm) films for high temperature applications are discussed. In addition, the influence of thermosetting and annealing processes on mechanical properties is investigated. PMID:22205871

  18. Characterization of Acoustic Resonance in a High-Pressure Sodium Lamp

    OpenAIRE

    Chhun, Labo; Maussion, Pascal; Bhosle, Sounil; Zissis, Georges

    2011-01-01

    International audience With the last decades, the high pressure sodium (HPS) lamp has been supplied in high frequency in order to increase the efficacy of the lamp/ballast system. However, at some given frequencies, standing acoustic waves, namely acoustic resonance (AR), might develop in the burner and cause lamp luminous fluctuation, extinction and destruction in the most serious case. As we seek for a control method to detect and avoid the lamp AR some main characteristics of the acoust...

  19. G-tunnel pressurized slot-testing evaluations; Yucca Mountain Site Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, R.M.; Sifre-Soto, C. [Sandia National Labs., Albuquerque, NM (United States); Mann, K.L.; Bellman, R.A. Jr.; Luker, S. [Science Applications International Corp., Las Vegas, NV (United States); Dodds, D.J. [North Pacific Research, Portland, OR (United States)

    1992-04-01

    Designers and analysts of radioactive waste repositories must be able to predict the mechanical behavior of the host rock. Sandia National Laboratories elected to conduct a development program to enhance mechanical-type measurements. The program was focused on pressurized slot testing and featured (1) development of an improved method to cut slots using a chain saw with diamond-tipped cutters, (2) measurements useful for determining in situ stresses normal to slots, (3) measurements applicable for determining the in situ modulus of deformation parallel to a drift surface, and (4) evaluations of pressurized slot strength testing results and methods. This report contains data interpretation and evaluations. Included are recommendations for future efforts. This third report contains the interpretations of the testing with emphasis on the measurement results as they apply to describing rock behavior. In particular, emphases are placed on (1) normal stress determinations using the flatjack cancellation (FC) method, (2) modulus of deformation determinations, and (3) high pressure investigations. Most of the material in the first two reports is not repeated here. Appropriate data are repeated in tabular form.

  20. Mechanical testing and microstructural characterization of pressure vessel at decommissioned Belgian BR3 Plant

    International Nuclear Information System (INIS)

    The objective of this paper was a discussion of a proposal to perform mechanical testing and microstructural characterization of the annealed reactor vessel of the Belgian BR-3 reactor. Motivation for this effort was discussed, and a preliminary cost estimate for some of the tasks was also presented

  1. Characterization of atmospheric pressure plasma treated pure cashmere and wool/cashmere textiles: Treatment in air/water vapor mixture

    Energy Technology Data Exchange (ETDEWEB)

    Zanini, Stefano, E-mail: stefano.zanini@mib.infn.it [Università degli Studi di Milano-Bicocca, Dipartimento di Fisica “G. Occhialini”, p.za della Scienza, 3, I-20126 Milano (Italy); Grimoldi, Elisa [Università degli Studi di Milano-Bicocca, Dipartimento di Fisica “G. Occhialini”, p.za della Scienza, 3, I-20126 Milano (Italy); Citterio, Attilio [Politecnico di Milano, Dipartimento di Chimica, Materiali ed Ingegneria Chimica “G. Natta”, Via Mancinelli 7, I-20131 Milano (Italy); Riccardi, Claudia, E-mail: riccardi@mib.infn.it [Università degli Studi di Milano-Bicocca, Dipartimento di Fisica “G. Occhialini”, p.za della Scienza, 3, I-20126 Milano (Italy)

    2015-09-15

    Highlights: • We treated cashmere and wool/cashmere textiles with atmospheric pressure plasma. • Wettability of the fabrics was increased. • The increment in wettability derived from a surface oxidation of the fibers. • Only minor etching effects were observed with scanning electron microscopy. - Abstract: We performed atmospheric pressure plasma treatments of pure cashmere and wool/cashmere textiles with a dielectric barrier discharge (DBD) in humid air (air/water vapor mixtures). Treatment parameters have been optimized in order to enhance the wettability of the fabrics without changing their bulk properties as well as their touch. A deep characterization has been performed to study the wettability, the surface morphologies, the chemical composition and the mechanical properties of the plasma treated textiles. The chemical properties of the plasma treated samples were investigated with attenuated total reflectance Fourier transform infrared (FTIR/ATR) spectroscopy and X-ray photoelectron microscopy (XPS). The analyses reveal a surface oxidation of the treated fabrics, which enhances their surface wettability. Morphological characterization of the treated fibers with scanning electron microscopy (SEM) reveals minor etching effects, an essential feature for the maintenance of the textile softness.

  2. Characterization of atmospheric pressure plasma treated pure cashmere and wool/cashmere textiles: Treatment in air/water vapor mixture

    International Nuclear Information System (INIS)

    Highlights: • We treated cashmere and wool/cashmere textiles with atmospheric pressure plasma. • Wettability of the fabrics was increased. • The increment in wettability derived from a surface oxidation of the fibers. • Only minor etching effects were observed with scanning electron microscopy. - Abstract: We performed atmospheric pressure plasma treatments of pure cashmere and wool/cashmere textiles with a dielectric barrier discharge (DBD) in humid air (air/water vapor mixtures). Treatment parameters have been optimized in order to enhance the wettability of the fabrics without changing their bulk properties as well as their touch. A deep characterization has been performed to study the wettability, the surface morphologies, the chemical composition and the mechanical properties of the plasma treated textiles. The chemical properties of the plasma treated samples were investigated with attenuated total reflectance Fourier transform infrared (FTIR/ATR) spectroscopy and X-ray photoelectron microscopy (XPS). The analyses reveal a surface oxidation of the treated fabrics, which enhances their surface wettability. Morphological characterization of the treated fibers with scanning electron microscopy (SEM) reveals minor etching effects, an essential feature for the maintenance of the textile softness

  3. HIPPO, the high-pressure preferred orientation diffractometer at LANSCE for characterization of bulk materials

    International Nuclear Information System (INIS)

    United States National Laboratory researchers and University of California faculty, representing a broad range of scientific disciplines, is building a novel time-of-flight (TOF) neutron diffractometer and associated in situ equipment at the Manuel Lujan Jr. Neutron Scattering Center (Lujan Center), under the auspices of the United States Department of Energy. The goal with the High-Pressure Preferred Orientation Instrument (HIPPO) is to investigate dynamic processes in heterogeneous bulk materials in a variety of environments. The instrument, which will become available in summer 2001, has the extremely high count-rates necessary to study time-dependent processes in small (1-mm diameter) and large (2-cm diameter) samples, and in a large variety of environmental conditions (10-2000 K cryostats and furnaces, 0-20 GPa pressure vessels, straining cells, goniometers, magnets, etc.). The 3-D arrangement of detectors allows direct measurements of crystal orientation distributions in polycrystalline materials. The analysis of TOF diffraction patterns with versatile Rietveld codes provides simultaneous information on crystal structure, texture, microstructure and phase proportions. While this instrument has many applications in materials science, it is also of great interest for geology and geophysics. Some applications include: kinetics of reactions, structure of silicate glasses and melts, high-pressure investigations of complex systems, evolution of texture and anisotropy during deformation and recrystallization. The Lujan Center aims at creating an instrument with high data through-put and easy access to researchers and students. While the HIPPO instrument will be part of the national user facility operated by the Lujan Center, the scientific program will be guided by the University of California consortium with the goal of satisfying national priorities and establishing an environment of scientific excellence. (author)

  4. Analysis and simulation of propagule dispersal and salinity intrusion from storm surge on the movement of a marsh–mangrove ecotone in South Florida

    Science.gov (United States)

    Jiang, Jiang; DeAngelis, Donald L.; Anderson, Gordon H.; Smith, Thomas J., III

    2014-01-01

    Coastal mangrove–freshwater marsh ecotones of the Everglades represent transitions between marine salt-tolerant halophytic and freshwater salt-intolerant glycophytic communities. It is hypothesized here that a self-reinforcing feedback, termed a “vegetation switch,” between vegetation and soil salinity, helps maintain the sharp mangrove–marsh ecotone. A general theoretical implication of the switch mechanism is that the ecotone will be stable to small disturbances but vulnerable to rapid regime shifts from large disturbances, such as storm surges, which could cause large spatial displacements of the ecotone. We develop a simulation model to describe the vegetation switch mechanism. The model couples vegetation dynamics and hydrologic processes. The key factors in the model are the amount of salt-water intrusion into the freshwater wetland and the passive transport of mangrove (e.g., Rhizophora mangle) viviparous seeds or propagules. Results from the model simulations indicate that a regime shift from freshwater marsh to mangroves is sensitive to the duration of soil salinization through storm surge overwash and to the density of mangrove propagules or seedlings transported into the marsh. We parameterized our model with empirical hydrologic data collected from the period 2000–2010 at one mangrove–marsh ecotone location in southwestern Florida to forecast possible long-term effects of Hurricane Wilma (24 October 2005). The model indicated that the effects of that storm surge were too weak to trigger a regime shift at the sites we studied, 50 km south of the Hurricane Wilma eyewall, but simulations with more severe artificial disturbances were capable of causing substantial regime shifts.

  5. Mechanical and histological characterization of trachea tissue subjected to blast-type pressures

    Science.gov (United States)

    Butler, B. J.; Bo, C.; Tucker, A. W.; Jardine, A. P.; Proud, W. G.; Williams, A.; Brown, K. A.

    2014-05-01

    Injuries to the respiratory system can be a component of polytrauma in blast-loading injuries. Tissues located at air-liquid interfaces, including such tissues in the respiratory system, are particularly vulnerable to damage by blast overpressures. There is a lack of information about the mechanical and cellular responses that contribute to the damage of this class of tissues subjected to the high strain rates associated with blast loading. Here, we describe the results of dynamic blast-like pressure loading tests at high strain rates on freshly harvested ex vivo trachea tissue specimens.

  6. Characterization of pores in high pressure die cast aluminum using active thermography and computed tomography

    Science.gov (United States)

    Maierhofer, Christiane; Myrach, Philipp; Röllig, Mathias; Jonietz, Florian; Illerhaus, Bernhard; Meinel, Dietmar; Richter, Uwe; Miksche, Ronald

    2016-02-01

    Larger high pressure die castings (HPDC) and decreasing wall thicknesses are raising the issue of casting defects like pores in aluminum structures. Properties of components are often strongly influenced by inner porosity. As these products are being established more and more in lightweight construction (e.g. automotive and other transport areas), non-destructive testing methods, which can be applied fast and on-site, are required for quality assurance. In this contribution, the application of active thermography for the direct detection of larger pores is demonstrated. The analysis of limits and accuracy of the method are completed by numerical simulation and the method is validated using computed tomography.

  7. Intercomparison of techniques for inspection and diagnostics of heavy water reactor pressure tubes: Flaw detection and characterization [Phase 1

    International Nuclear Information System (INIS)

    Nuclear power plants with heavy water reactors (HWRs) comprise nine percent of today's operating nuclear units, and more are under construction. Efficient and accurate inspection and diagnostic techniques for various reactor components and systems are an important factor in assuring reliable and safe plant operation. To foster international collaboration in the efficient and safe use of nuclear power, the IAEA conducted a Coordinated Research Programme (CRP) on Inter-comparison of Techniques for HWR Pressure Tube Inspection and Diagnostics. This CRP was carried out within the frame of the IAEA Department of Nuclear Energy's Technical Working Group on Advanced Technologies for HWRs (the TWG-HWR). The TWG-HWR is a group of experts nominated by their governments and designated by the IAEA to provide advice and to support implementation of the IAEA's project on advanced technologies for HWRs. The objective of the CRP was to inter-compare non-destructive inspection and diagnostic techniques, in use and being developed, for structural integrity assessment of HWR pressure tubes. During the first phase of this CRP, participants have investigated the capability of different techniques to detect and characterize flaws. During the second phase of this CRP, participants collaborated to detect and characterize hydride blisters and to determine the hydrogen concentration in Zirconium alloys. The intent was to identify the most effective pressure tube inspection and diagnostic methods, and to identify further development needs. The organizations that have participated in this CRP are: - The Comision Nacional de Energia Atomica (CNEA), Argentina; - Atomic Energy of Canada Ltd. (AECL); Chalk River Laboratories (CRL), Canada; - The Research Institute of Nuclear Power Operations (RINPO), China National Nuclear Corporation (CNNC), China; - Bhabha Atomic Research Centre (BARC), India; - The Korea Electric Power Research Institute (KEPRI), Republic of Korea; - The Korea Atomic Energy

  8. Characterization of pulsed atmospheric-pressure plasma streams (PAPS) generated by a plasma gun

    International Nuclear Information System (INIS)

    An experimental study of atmospheric-pressure rare gas plasma propagation in a high-aspect-ratio capillary is reported. The plasma is generated with a plasma gun device based on a dielectric barrier discharge (DBD) reactor powered by either nanosecond or microsecond rise-time high-voltage pulses at single-shot to multi-kHz frequencies. The influence of the voltage waveform, pulse polarity, pulse repetition rate and capillary material have been studied using nanosecond intensified charge-coupled device imaging and plasma-front velocity measurements. The evolution of the plasma appearance during its propagation and the study of the role of the different experimental parameters lead us to suggest a new denomination of pulsed atmospheric-pressure plasma streams to describe all the plasma features, including the previously so-called plasma bullet. The unique properties of such non-thermal plasma launching in capillaries, far from the primary DBD plasma, are associated with a fast ionization wave travelling with velocity in the 107–108 cm s−1 range. Voltage pulse tailoring is shown to allow for a significant improvement of such plasma delivery. Thus, the plasma gun device affords unique opportunities in biomedical endoscopic applications. (paper)

  9. In-vivo characterization of left-ventricle pressure-volume telemetry system in swine model.

    Science.gov (United States)

    Fricke, Kyle; Konecny, Filip; El-Warrak, Alexander; Hodgson, Chad; Cadieux-Pitre, Heather; Hill, Tracy; Sobot, Robert

    2016-10-01

    We present in-vivo study related to the use of our implantable RF telemetry system for pressure-volume (PV) cardiac monitoring in a animal subject. We implant a commercial MEMS PV sensor into the subject's heart left-ventricle (LV), while the telemetry system is implanted outside of the heart and connected to the sensor with a 7-microwires tether. The RF telemetry system is suitable for commercial application in medium sized subjects, its total volume of 2.475cm(3) and a weight of 4.0g. Our designed system is 58 % smaller in volume, 44 % in weight and has a 55 % reduction in sampling power over the last reported research in PV telemetry. In-vivo data was captured in both an acute and a freely moving setting over a 24 hour period. We experimentally demonstrated viability of the methodology that includes the surgical procedure and real-time monitoring of the in-vivo data in a freely moving subject. Further improvements in catheter design will improve the data quality and safety of the subject. This real-time implantable technology allows for researchers to quantify cardiac pathologies by extracting real-time pressure-volume loops, wirelessly from within freely moving subjects. PMID:27492638

  10. Characterization and comparison of laser induced plasma parameters by Langmuir probe at low pressure

    Directory of Open Access Journals (Sweden)

    N Morshedian

    2015-07-01

    Full Text Available In this paper, the electron temperature and ion density of laser-produced plasma in nanosecond regime in different pressure of ambient gas have been studied by using single Langmuir probe. Using the current-voltage characteristics curve of probe, the value of electron temperature in different pressure (range of 10-5×10-5 mbar is in the range of 2-29 eV and also the ion density estimated about 1013 cm-3 in millimeter scale and 1011 cm-3 in centimeters scale from target to probe. . It is important that regardless of I-V characteristic of Langmuir probe, having time of maxim current signal of probe at certain distance from target surface, it would be possible to obtain the particles speed by time of flight method. The results show that the electrons and ions speeds are about 108 cm/s and 106cm/s respectively. Also the results of this experiment are Comparable with other techniques such as Shadowgraphy in the similar experimental conditions.

  11. Cytocompatibility evaluation and surface characterization of TiNi deformed by high-pressure torsion

    International Nuclear Information System (INIS)

    Effect of high-pressure torsion (HPT) deformation on biocompatibility and surface chemistry of TiNi was systematically investigated. Ti–50 mol% Ni was subjected to HPT straining for different numbers of turns, N = 0.25, 0.5, 1, 5 and 10 at a rotation speed of 1 rpm. X-ray photoelectron spectroscopy observations after 7 days of cell culture revealed the changes in the surface oxide composition, enrichment of Ti and detection of nitrogen derived from organic molecules in the culture medium. Plating efficiency of L929 cells was slightly increased by HPT deformation though no significant difference was observed. Albumin adsorption was higher in HPT-deformed samples, while vitronectin adsorption was peaked at N = 1. HPT deformation was also found to effectively suppress the Ni ion release from the TiNi samples into the cell culture medium even after the low degree of deformation at N = 0.25. - Highlights: • Nanostructured Ti–50 mol%Ni alloy was produced using high-pressure torsion. • HPT deformation improved L929 growth on TiNi samples. • Changes in surface chemistry were observed in HPT deformed samples. • Protein adsorption behavior was influenced by the surface chemistry. • Ni ion release was suppressed in HPT deformed samples

  12. Synthesis and Characterization of Nanofibrous Polyaniline Thin Film Prepared by Novel Atmospheric Pressure Plasma Polymerization Technique

    Directory of Open Access Journals (Sweden)

    Choon-Sang Park

    2016-01-01

    Full Text Available This work presents a study on the preparation of plasma-polymerized aniline (pPANI nanofibers and nanoparticles by an intense plasma cloud type atmospheric pressure plasma jets (iPC-APPJ device with a single bundle of three glass tubes. The nano size polymer was obtained at a sinusoidal wave with a peak value of 8 kV and a frequency of 26 kHz under ambient air. Discharge currents, photo-sensor amplifier, and optical emission spectrometer (OES techniques were used to analyze the plasma produced from the iPC-APPJ device. Field emission scanning electron microscopy (FE-SEM, transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FT-IR, gas chromatography-mass spectrometry (GC-MS, and gel permeation chromatography (GPC techniques were used to analyze the pPANI. FE-SEM and TEM results show that pPANI has nanofibers, nanoparticles morphology, and polycrystalline characteristics. The FT-IR and GC-MS analysis show the characteristic polyaniline peaks with evidence that some quinone and benzene rings are broken by the discharge energy. GPC results show that pPANI has high molecular weight (Mw, about 533 kDa with 1.9 polydispersity index (PDI. This study contributes to a better understanding on the novel growth process and synthesis of uniform polyaniline nanofibers and nanoparticles with high molecular weights using the simple atmospheric pressure plasma polymerization technique.

  13. Topological characterization of flow structures in resistive pressure-gradient-driven turbulence

    Science.gov (United States)

    Carreras, B. A.; Llerena, I.; Garcia, L.; Calvo, I.

    2008-12-01

    Visualization of turbulent flows is a powerful tool to help understand the turbulence dynamics and induced transport. However, it does not provide a quantitative description of the observed structures. In this paper, an approach to characterize quantitatively the topology of the flows is given. The technique, which can be applied to any type of turbulence dynamics, is illustrated through the example of resistive ballooning instabilities.

  14. Topological characterization of flow structures in resistive pressure-gradient-driven turbulence

    CERN Document Server

    Carreras, Benjamin A; Garcia, Luis; Calvo, Ivan

    2008-01-01

    Visualization of turbulent flows is a powerful tool to help understand the turbulence dynamics and induced transport. However, it does not provide a quantitative description of the observed structures. In this paper, an approach to characterize quantitatively the topology of the flows is given. The technique, which can be applied to any type of turbulence dynamics, is illustrated through the example of resistive ballooning instabilities.

  15. Plasma-mediated vascular dysfunction in the reduced uterine perfusion pressure model of preeclampsia: a microvascular characterization.

    LENUS (Irish Health Repository)

    Walsh, Sarah K

    2012-01-31

    Preeclampsia is associated with widespread maternal vascular dysfunction, which is thought to be mediated by circulating factor(s). The aim of the study was to characterize vascular function in the reduced uterine perfusion pressure (RUPP) rat model of preeclampsia and to investigate the role of plasma factors in mediating any observed changes in vascular reactivity. Mean arterial blood pressure and vascular function were measured in RUPP and control rats. Mesenteric vessels from both virgin and pregnant rats were exposed for 1 hour or overnight to plasma from both RUPP and control rats and their vascular function assessed. RUPP rats were characterized by severe hypertension, restricted fetal growth, and reduced placental weight (P<0.001). Vasorelaxation was impaired in resistance vessels from RUPP compared with control rats (acetylcholine: R(max) 70+\\/-3 versus 92+\\/-1 [NP] and 93+\\/-3% [sham], P<0.01; bradykinin: 40+\\/-2 versus 62+\\/-2 [NP] and 59+\\/-4% [sham], P<0.001). Incubation of vessels from pregnant (but not virgin) animals with RUPP plasma overnight resulted in an attenuation of vasorelaxant responses (acetylcholine: 63+\\/-7 versus 86+\\/-2%, P<0.05; bradykinin: 35+\\/-5 versus 55+\\/-6%, P<0.001). The residual relaxant response in RUPP plasma-treated vessels was not further attenuated after treatment with N(omega)-nitro-l-arginine methyl ester (acetylcholine: 57+\\/-7 versus 63+\\/-7%, ns; bradykinin: 37+\\/-5 versus 35+\\/-5%, ns). The RUPP rat model is characterized by an impaired response to vasodilators which may be attributable to one or more circulating factors. This plasma-mediated endothelial dysfunction appears to be a pregnancy-dependent effect. Furthermore, nitric oxide-mediated vasorelaxation appears to be absent in RUPP plasma-treated vessels.

  16. Characterization of excel alloy pressure tube material for CANDU SCW reactors

    International Nuclear Information System (INIS)

    The phase transformation temperatures, aging response, and creep rupture strength of Zr alloy Excel (Zr- 3.5%Sn- 0.8%Nb- 0.8%Mo) pressure tube material were investigated. The α → α+β and α+β → β transus temperatures were found to be in the range of 600-690 °C and 962-975 °C respectively. Precipitation hardening was observed in the microstructures water-quenched from high in the α+β or β regions followed by aging at 400-500 °C for 1 hr. The results of creep-rupture experiments at 400 °C suggest that a fully martensitic and aged microstructure has better creep properties at high stress levels (>700 MPa) and a microstructure obtained by air-cooling from high in the α+β region shows good creep properties at lower stresses (<560 MPa). (author)

  17. Generation and characterization of OH and O radicals by atmospheric pressure steam/oxygen plasma

    CERN Document Server

    Roy, N C; Alam, M K; Talukder, M R

    2016-01-01

    Atmospheric pressure steam/oxygen plasma is generated by a 88 Hz, 6kV AC power supply. The properties of the produced plasma are investigated by optical emission spectroscopy (OES). The relative intensity, rotational, vibrational, excitation temperatures and electron density are studied as function of applied voltage, electrode spacing and oxygen flow rate. The rotational and vibrational temperatures are determined simulating the bands with the aid of LIFBASE simulation software. The excitation temperature is obtained from the CuI transition taking non-thermal equilibrium condition into account employing intensity ratio method. The electron density is approximated from the H_{\\alpha} Stark broadening using the Voigt profile fitting method. It is observed that the rotational and vibrational temperatures are decreased with increasing electrode spacing and O2 flow rate, but increased with the applied voltage. The excitation temperature is found to increase with increasing applied voltage and O2 flow rate, but de...

  18. Characterization of transient discharges under atmospheric pressure conditions applying nitrogen photoemission and current measurements

    CERN Document Server

    Keller, Sandra; Bibinov, Nikita; Awakowicz, Peter

    2011-01-01

    Plasma parameters of three transient discharges (filamentary and homogeneous dielectric barrier discharges in air, and the spark discharge of an argon plasma coagulator) operated at atmospheric pressure conditions are determined applying a combination of diagnostics methods, namely numerical simulation, current measurement, and optical emission spectroscopy. These diagnostic methods supplement each other and resolve problems, which arise when these methods are used separately. Nitrogen is used as sensor gas and is admixed to argon for studying the argon plasma coagulator. The Boltzmann equation is solved in 'local' approximation to determine electron velocity distribution function. Drift velocity, electron-impact excitation rate constants for nitrogen molecular emission, electric current density, and emission spectrum of nitrogen molecule are calculated. Plasma parameters (electron velocity distribution function and electron density) are determined applying calculated as far as measured electric current, and ...

  19. Defect Characterization in Ge/(001)Si Epitaxial Films Grown by Reduced-Pressure Chemical Vapor Deposition

    Science.gov (United States)

    Bharathan, Jayesh; Narayan, Jagdish; Rozgonyi, George; Bulman, Gary E.

    2013-10-01

    We studied the microstructural characteristics and electrical properties of epitaxial Ge films grown on Si(001) substrates by x-ray diffraction, atomic force microscopy, and transmission electron microscopy. The films were grown using a two-step technique by reduced-pressure chemical vapor deposition, where the first step promotes two-dimensional growth at a lower substrate temperature. We observed a decrease in defect density with increasing film thickness. Ge films with thickness of 3.5 μm exhibited threading dislocation densities of 5 × 106 cm-2, which yielded devices with dark current density of 5 mA cm-2 (1 V reverse bias). We also noted the presence of stacking faults in the form of lines in the films and establish that this is an important defect for Ge films grown by this deposition technique.

  20. Characterizations of atmospheric pressure low temperature plasma jets and their applications

    Science.gov (United States)

    Karakas, Erdinc

    2011-12-01

    Atmospheric pressure low temperature plasma jets (APLTPJs) driven by short pulses have recently received great attention because of their potential in biomedical and environmental applications. This potential is due to their user-friendly features, such as low temperature, low risk of arcing, operation at atmospheric pressure, easy handheld operation, and low concentration of ozone generation. Recent experimental observations indicate that an ionization wave exists and propagates along the plasma jet. The plasma jet created by this ionization wave is not a continuous medium but rather consists of a bullet-like-structure known as "Plasma Bullet". More interestingly, these plasma bullets actually have a donut-shaped makeup. The nature of the plasma bullet is especially interesting because it propagates in the ambient air at supersonic velocities without any externally applied electric field. In this dissertation, experimental insights are reported regarding the physical and chemical characteristics of the APLTPJs. The dynamics of the plasma bullet are investigated by means of a high-speed ICCD camera. A plasma bullet propagation model based on the streamer theory is confirmed with adequate explanations. It is also found that a secondary discharge, ignited by the charge accumulation on the dielectric electrode surfaces at the end of the applied voltage, interrupts the plasma bullet propagation due to an opposing current along the ionization channel. The reason for this interesting phenomenon is explained in detail. The plasma bullet comes to an end when the helium mole fraction along the ionization channel, or applied voltage, or both, are less than some critical values. The presence of an inert gas channel in the surrounding air, such as helium or argon, has a critical role in plasma bullet formation and propagation. For this reason, a fluid dynamics study is employed by a commercially available simulation software, COMSOL, based on finite element method. Spatio

  1. Development and Characterization of a Hybrid Atmospheric Pressure Plasma Electrospinning System for Nanofiber Enhancement

    Science.gov (United States)

    Nowak, Joshua Michael

    A hybrid atmospheric pressure-electrospinning plasma system was developed to be used for the production of nanofibers and enhance their performance for various applications. Electrospun nanofibers are excellent candidates for protective clothing in the field of chemical and biological warfare defense; however, nanofibers are structurally weak and easily abrade and tear. They can be strengthened through the support of a substrate fabric, but they do not adhere well to substrates. Through the use of the developed hybrid system with either pure He or He/O2 (99/1) feed gas, adherence to the substrate along with abrasion and flex resistance were improved. The plasma source was diagnosed electrically, thermally, and optically. An equivalent circuit model was developed for non-thermal, highly collisional plasmas that can solve for average electron temperature and electron number density. The obtained temperatures (~ 3eV) correlate very well with the results of a neutral Bremsstrahlung continuum matching technique that was also employed. Using the temperatures and number densities obtained from the circuit model and the optical spectroscopy, a global chemical kinetics code was written in order to solve for radical and ion concentrations. This code shows that there are significant concentrations of oxygen radicals present. The XPS analysis confirmed that there was an increase of surface oxygen from 11.1% up to 16.6% for the He/O2 plasma and that the C-O bonding, which was not present in the control samples, has increased to 45.4%. The adhesive strength to the substrate has a significant increase of 81% for helium plasma and 144% for He/O2 plasma; however, these values remain below the desired values for protective clothing applications. The hybrid system displayed the ability to oxygenate nanofibers as they are being electrospun and shows the feasibility of making other surface modifications. The developed circuit model and chemical kinetics code both show promise as tools

  2. Fourier transform infrared absorption spectroscopy characterization of gaseous atmospheric pressure plasmas with 2 mm spatial resolution

    Energy Technology Data Exchange (ETDEWEB)

    Laroche, G. [Laboratoire d' Ingenierie de Surface, Centre de Recherche sur les Materiaux Avances, Departement de genie des mines, de la metallurgie et des materiaux, Universite Laval, 1065, avenue de la Medecine, Quebec G1V 0A6 (Canada); Centre de recherche du CHUQ, Hopital St Francois d' Assise, 10, rue de l' Espinay, local E0-165, Quebec G1L 3L5 (Canada); Vallade, J. [Laboratoire Procedes, Materiaux et Energie Solaire, PROMES, CNRS, Technosud, Rambla de la Thermodynamique, F-66100 Perpignan (France); Agence de l' environnement et de la Ma Latin-Small-Letter-Dotless-I -carettrise de l' Energie, 20, avenue du Gresille, BP 90406, F-49004 Angers Cedex 01 (France); Bazinette, R.; Hernandez, E.; Hernandez, G.; Massines, F. [Laboratoire Procedes, Materiaux et Energie Solaire, PROMES, CNRS, Technosud, Rambla de la Thermodynamique, F-66100 Perpignan (France); Nijnatten, P. van [OMT Solutions bv, High Tech Campus 9, 5656AE Eindhoven (Netherlands)

    2012-10-15

    This paper describes an optical setup built to record Fourier transform infrared (FTIR) absorption spectra in an atmospheric pressure plasma with a spatial resolution of 2 mm. The overall system consisted of three basic parts: (1) optical components located within the FTIR sample compartment, making it possible to define the size of the infrared beam (2 mm Multiplication-Sign 2 mm over a path length of 50 mm) imaged at the site of the plasma by (2) an optical interface positioned between the spectrometer and the plasma reactor. Once through the plasma region, (3) a retro-reflector module, located behind the plasma reactor, redirected the infrared beam coincident to the incident path up to a 45 Degree-Sign beamsplitter to reflect the beam toward a narrow-band mercury-cadmium-telluride detector. The antireflective plasma-coating experiments performed with ammonia and silane demonstrated that it was possible to quantify 42 and 2 ppm of these species in argon, respectively. In the case of ammonia, this was approximately three times less than this gas concentration typically used in plasma coating experiments while the silane limit of quantification was 35 times lower. Moreover, 70% of the incoming infrared radiation was focused within a 2 mm width at the site of the plasma, in reasonable agreement with the expected spatial resolution. The possibility of reaching this spatial resolution thus enabled us to measure the gaseous precursor consumption as a function of their residence time in the plasma.

  3. Synthesis and characterization of nanocrystalline hexagonal boron carbo-nitride under high temperature and high pressure

    International Nuclear Information System (INIS)

    A study of the synthesis of hexagonal boron carbo-nitride (h-BCN) compounds via a two-step high-temperature and high-pressure (HTHP) technique using melamine (C3N6H6) and boron oxide (B2O3) as raw materials is presented. An amorphous BCN precursor was prepared at 1000 K under vacuum in a resistance furnace and then single-phase h-BCN nanocrystalline was synthesized at 1600 K and 5.1 GPa in a multi-anvil apparatus. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the final products were pure h-BCN crystals with the lattice constants a 0.2510 nm and c = 0.6690 nm. The average grain size was about 150 nm. X-ray photoelectron spectroscopy (XPS) results confirmed the occurrence of bonding between C-C, C-N, C-B and N-B atoms. Raman scattering analysis suggested that there were three strong Raman bands centered at 1359, 1596 and 1617 cm-1, respectively. The band at 1617 cm-1 was considered to be consistent with the characteristic Raman peak of h-BCN

  4. Characterization of the high-pressure superconductivity in the Pnma phase of calcium

    Energy Technology Data Exchange (ETDEWEB)

    Szczesniak, R. [Institute of Physics, Czestochowa University of Technology, Al. Armii Krajowej 19, 42-200 Czestochowa (Poland); Szczesniak, D. [Institute of Physics, Jan Dlugosz University in Czestochowa, Al. Armii Krajowej 13/15, 42-200 Czestochowa (Poland); Institute for Molecules and Materials, UMR 6283, University of Maine, Ave. Olivier Messiaen, 72085 Le Mans (France)

    2012-11-15

    The thermodynamic parameters of the superconducting state in calcium under the pressure of 161 GPa have been calculated within the framework of the Eliashberg approach. It has been shown that the value of the Coulomb pseudopotential is high and the critical temperature (T{sub C} = 25 K) should be determined from the modified Allen-Dynes formula. In addition, it has been found that the basic dimensionless ratios of the thermodynamic parameters significantly diverge from the BCS predictions, and take the following values: (i) The zero-temperature energy gap to the critical temperature is equal to 4.01. (ii) The ratio R{sub 2} {identical_to}(C{sup S} (T{sub C})- C{sup N} (T{sub C}))/C{sup N} (T{sub C}) equals 2.17, where C{sup S} and C{sup N} denote the specific heats for the superconducting and normal states, respectively. (iii) The quantity R{sub 3} {identical_to}T{sub C} C{sup N} (T{sub C})/H{sub C}{sup 2} (0) = 0.158, where H{sub C} indicates the thermodynamic critical field. Finally, it has been proven that the electron effective mass is large and takes the maximum of 2.32m{sub e} at T{sub C}. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Enzymatic saccharification of high pressure assist-alkali pretreated cotton stalk and structural characterization.

    Science.gov (United States)

    Du, Shuang-kui; Su, Xia; Yang, Weihua; Wang, Yanqin; Kuang, Meng; Ma, Lei; Fang, Dan; Zhou, Dayun

    2016-04-20

    Cotton stalk is a potential biomass for bioethanol production, while the conversion of direct saccharification or biotransformation of cotton stalk is extremely low due to the recalcitrant nature of lignocellulose. To enhance the enzymatic conversion of cotton stalks, the enzymatic saccharification parameters of high pressure assist-alkali pretreatment (HPAP) cotton stalk were optimized in the present study. Results indicated that a maximum reducing sugar yield of 54.7g/100g dry biomass cellulose was achieved at a substrate concentration of 2%, 100rpm agitation, 0.6g/g enzyme loading, 40°C hydrolysis temperature, 50h saccharification time, and pH 5.0. Scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy were used to identify structural changes in native, pretreated biomass and hydrolyzed residues. Structural analysis revealed large part of amorphous cellulose and partial crystalline cellulose in the HPAP cotton stalk were hydrolyzed during enzymatic treatment. HPAP cotton stalk can be used as a potential feed stock for bioethanol production. PMID:26876855

  6. Characterization of pore structure and hydraulic property alteration in pressurized unsaturated flow tests

    International Nuclear Information System (INIS)

    The pressurized unsaturated flow (PUF) test is a new experimental method for the evaluation of the long-term corrosion behavior of waste forms and other engineered barrier materials. Essentially, the technique provides a means to flow water through a porous bed of test material or materials at elevated temperature and under hydraulically unsaturated conditions. Bulk volumetric content, effluent pH and electrical conductivity are monitored in real time using a computer control and data acquisition system. In previous papers, the authors have reported on the changes in bulk water content, effluent chemistry, and glass corrosion rates that result from the formation of alteration products during these tests. These measurements are now supplemented through the use of the ultracentrifugation apparatus (UFA) for hydraulic property measurements and high-resolution, x-ray microtomography (XMT) to provide 3-D spatial and temporal imaging of water distribution and pore structure alteration during these tests. Quantitative changes in the water retention characteristic were correlated with the onset of zeolite formation in the tests. Extensive alteration of the glass resulted in cementation of the glass grains near the bottom of the column, which was observed in situ using the XMT

  7. Fourier transform infrared absorption spectroscopy characterization of gaseous atmospheric pressure plasmas with 2 mm spatial resolution

    International Nuclear Information System (INIS)

    This paper describes an optical setup built to record Fourier transform infrared (FTIR) absorption spectra in an atmospheric pressure plasma with a spatial resolution of 2 mm. The overall system consisted of three basic parts: (1) optical components located within the FTIR sample compartment, making it possible to define the size of the infrared beam (2 mm × 2 mm over a path length of 50 mm) imaged at the site of the plasma by (2) an optical interface positioned between the spectrometer and the plasma reactor. Once through the plasma region, (3) a retro-reflector module, located behind the plasma reactor, redirected the infrared beam coincident to the incident path up to a 45° beamsplitter to reflect the beam toward a narrow-band mercury-cadmium-telluride detector. The antireflective plasma-coating experiments performed with ammonia and silane demonstrated that it was possible to quantify 42 and 2 ppm of these species in argon, respectively. In the case of ammonia, this was approximately three times less than this gas concentration typically used in plasma coating experiments while the silane limit of quantification was 35 times lower. Moreover, 70% of the incoming infrared radiation was focused within a 2 mm width at the site of the plasma, in reasonable agreement with the expected spatial resolution. The possibility of reaching this spatial resolution thus enabled us to measure the gaseous precursor consumption as a function of their residence time in the plasma.

  8. Characterization Testing of H20-SO2 Electrolyzer at Ambient Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Steimke, J

    2005-07-29

    This document reports work performed at the Savannah River National Laboratory (SRNL) that resulted in a major accomplishment by demonstrating the proof-of-concept of the use of a proton exchange membrane or PEM-type electrochemical cell to produce hydrogen via SO{sub 2}-depolarized water electrolysis. For the first time sulfur dioxide dissolved in liquid sulfuric acid was used to depolarize water electrolysis in a modern PEM cell. The use of such a cell represents a major step in achieving the ultimate goal of an economical hydrogen production process based on the Hybrid Sulfur (HyS) Cycle. The HyS Process is a hybrid thermochemical cycle that may be used in conjunction with advanced nuclear reactors or centralized solar receivers to produce hydrogen by water-splitting. Like all other sulfur-based cycles, HyS utilizes the high temperature thermal decomposition of sulfuric acid to produce oxygen. The unique aspect of HyS is the generation of hydrogen in a water electrolyzer that is operated under conditions where dissolved sulfur dioxide depolarizes the anodic reaction, resulting in substantial voltage reduction. Sulfur dioxide is oxidized at the anode, producing sulfuric acid, that is sent to the acid decomposition portion of the cycle. The focus of this work was to conduct single cell electrolyzer tests in order to prove the concept of SO{sub 2}-depolarization and to determine how the results can be used to evaluate the performance of key components of the HyS Process. A test facility for conducting SO{sub 2}-depolarized electrolyzer (SDE) testing was designed, constructed and commissioned. The maximum cell current is 50 amperes, which is equivalent to a hydrogen production rate of approximately 20 liters per hour. The test facility was designed for operation at room temperature with pressures up to 2 bar. Feed to the anode of the electrolyzer can be water, sulfuric acid of various concentrations, or sulfuric acid containing dissolved sulfur dioxide. Provisions

  9. Critical cleavage fracture stress characterization of A508 nuclear pressure vessel steels

    International Nuclear Information System (INIS)

    The critical cleavage fracture stress of SA508 Gr.4N and SA508 Gr.3 low alloy reactor pressure vessel (RPV) steels was studied through the combination of experiments and finite element method (FEM) analysis. The results showed that the value of the local cleavage fracture stress, σF, of SA508 Gr.4N steel was significantly higher than that of SA508 Gr.3 steel. Detailed microstructural analysis was carried out using FEGSEM which revealed much smaller grains, finer and more homogenous carbide particles formed in SA508 Gr.4N steel. Compared with the SA508 Gr.3 steel currently used in the nuclear industry, the SA508 Gr.4N steel possesses higher strength and notch toughness as well as improved cleavage fracture behavior, and is considered a better candidate RPV steel for the next generation nuclear reactors. - Highlights: • Critical cleavage fracture stress was calculated through experiments and FEM. • Effects of both grain and carbide particle sizes on σF were discussed. • The SA508 Gr.4N steel is a better candidate for the next generation nuclear reactors

  10. Pressurized liquid extraction and chemical characterization of safflower oil: A comparison between methods.

    Science.gov (United States)

    Conte, Rogério; Gullich, Letícia M D; Bilibio, Denise; Zanella, Odivan; Bender, João P; Carniel, Naira; Priamo, Wagner L

    2016-12-15

    This work investigates the extraction process of safflower oil using pressurized ethanol, and compares the chemical composition obtained (in terms of fatty acids) with other extraction techniques. Soxhlet and Ultrasound showed maximum global yield of 36.53% and 30.41%, respectively (70°C and 240min). PLE presented maximum global yields of 25.62% (3mLmin(-1)), 19.94% (2mLmin(-1)) and 12.37% (1mLmin(-1)) at 40°C, 100bar and 60min. Palmitic acid showed the lower concentration in all experimental conditions (from 5.70% to 7.17%); Stearic and Linoleic acid presented intermediate concentrations (from 2.93% to 25.09% and 14.09% to 19.06%, respectively); Oleic acid showed higher composition (from 55.12% to 83.26%). Differences between percentages of fatty acids, depending on method were observed. Results may be applied to maximize global yields and select fatty acids, reducing the energetic costs and process time. PMID:27451200

  11. Simultaneous microstructural and mechanical characterization of human corneas at increasing pressure.

    Science.gov (United States)

    Benoit, Aurélie; Latour, Gaël; Marie-Claire, Schanne-Klein; Allain, Jean-Marc

    2016-07-01

    The cornea, through its shape, is the main contributor to the eye׳s focusing power. Pathological alterations of the cornea strongly affect the eye power. To improve treatments, complex biomechanical models have been developed based on the architecture and mechanical properties of the collagen network in the stroma, the main layer of the cornea. However, direct investigations of the structure of the stroma, as well as its link to the mechanical response, remained limited. We propose here an original set up, associating nonlinear optical imaging and mechanical testing. By using polarization resolved Second Harmonic signals, we simultaneously quantified micrometer (orientation of the collagen lamellae) and nanometer (local disorder within lamellae) scale corneal organization. We showed that the organization of the lamellae changes along the stroma thickness. Then, we measured simultaneously the deformation on the epithelial side of the cornea and the reorientation of the collagen lamellae for increasing intraocular pressure levels, from physiological ones to pathological ones. We showed that the observed deformation is not correlated to initial orientation, but to the reorganization of the lamellae in the stroma. Our results, by providing a direct multi-scale observation, will be useful for the development of more accurate biomechanical models. PMID:26773650

  12. Characterization of Yttria-Stabilized Zirconia Coatings Deposited by Low-Pressure Plasma Spraying

    Science.gov (United States)

    He, Peng-jiang; Yin, Shuo; Song, Chen; Lapostolle, Frédéric; Liao, Han-lin

    2016-02-01

    The research presented here aimed to apply plasma spraying at a low pressure of 100 Pa for fabricating the columnar structure or dense coatings. These coatings with different structures were elaborated from the vapor condensation and molten droplets, respectively, using the agglomerated YSZ powders and a relatively low power commercial F4-VB torch. It was shown that the crystallite size of coating deposited from the vapor condensation at a spraying distance of 200 mm was reduced to 17.1 nm from 43.7 nm of the feedstock. Observations indicated that a thin columnar structured coating was produced out of the line of sight of projection. In the line of sight of projection, the hybrid structured coating was obtained. The relatively dense coating was fabricated using a specifically designed extended nozzle. Investigations by means of optical emission spectroscopy were performed to analyze the nature of the plasma jet with YSZ powders. The Vickers microhardness was also conducted. It was found that the relatively dense coating showed a higher value in comparison to the hybrid structure coating, up to 1273 ± 56 Hv100g.

  13. Characterization of a radio frequency hollow electrode discharge at low gas pressures

    Energy Technology Data Exchange (ETDEWEB)

    Ahadi, Amir Mohammad; Rehders, Stefan; Strunskus, Thomas; Faupel, Franz [Institute for Materials Science – Multicomponent Materials, University of Kiel, 24143 Kiel (Germany); Trottenberg, Thomas; Kersten, Holger [Institute of Experimental and Applied Physics, University of Kiel, 24098 Kiel (Germany)

    2015-08-15

    A radio frequency (RF) hollow discharge configuration is presented, which makes use of a combination of RF plasma generation and the hollow cathode effect. The system was especially designed for the treatment of nanoparticles, plasma polymerization, and nanocomposite fabrication. The process gas streams through the plasma in the inner of the cylindrical electrode system. In the here presented measurements, pure argon and argon with oxygen admixtures are exemplarily used. The discharge is characterized by probe measurements in the effluent, electrical measurements of the discharge parameters, and visual observations of the plasma glow. It is found that the RF fluctuations of the plasma potential are weak. The plasma potential resembles the one of a DC hollow cathode discharge, the RF hollow electrode acts as a cathode due to the self-bias, and a high voltage sheath forms in its inner cylinder.

  14. Characterization of a radio frequency hollow electrode discharge at low gas pressures

    International Nuclear Information System (INIS)

    A radio frequency (RF) hollow discharge configuration is presented, which makes use of a combination of RF plasma generation and the hollow cathode effect. The system was especially designed for the treatment of nanoparticles, plasma polymerization, and nanocomposite fabrication. The process gas streams through the plasma in the inner of the cylindrical electrode system. In the here presented measurements, pure argon and argon with oxygen admixtures are exemplarily used. The discharge is characterized by probe measurements in the effluent, electrical measurements of the discharge parameters, and visual observations of the plasma glow. It is found that the RF fluctuations of the plasma potential are weak. The plasma potential resembles the one of a DC hollow cathode discharge, the RF hollow electrode acts as a cathode due to the self-bias, and a high voltage sheath forms in its inner cylinder

  15. Characterization of a radio frequency hollow electrode discharge at low gas pressures

    Science.gov (United States)

    Ahadi, Amir Mohammad; Trottenberg, Thomas; Rehders, Stefan; Strunskus, Thomas; Kersten, Holger; Faupel, Franz

    2015-08-01

    A radio frequency (RF) hollow discharge configuration is presented, which makes use of a combination of RF plasma generation and the hollow cathode effect. The system was especially designed for the treatment of nanoparticles, plasma polymerization, and nanocomposite fabrication. The process gas streams through the plasma in the inner of the cylindrical electrode system. In the here presented measurements, pure argon and argon with oxygen admixtures are exemplarily used. The discharge is characterized by probe measurements in the effluent, electrical measurements of the discharge parameters, and visual observations of the plasma glow. It is found that the RF fluctuations of the plasma potential are weak. The plasma potential resembles the one of a DC hollow cathode discharge, the RF hollow electrode acts as a cathode due to the self-bias, and a high voltage sheath forms in its inner cylinder.

  16. Aerodynamic noise characterization of a full-scale wind turbine through high-frequency surface pressure measurements

    DEFF Research Database (Denmark)

    Bertagnolio, Franck; Aagaard Madsen, Helge; Bak, Christian;

    2015-01-01

    wind turbine with a 80 m diameter rotor as well as measurements of an airfoil section tested in a wind tunnel. The turbine was extensively equipped in order to monitor the local inflow onto the rotating blades. Further a section of the 38 m long blade was instrumented with 50 microphones flush......The aim of this work is to investigate and characterize the high-frequency surface pressure fluctuations on a full-scale wind turbine blade and in particular the influence of the atmospheric turbulence. As these fluctuations are highly correlated to the sources of both turbulent inflow noise and...... trailing edge noise, recognized to be the two main sources of noise from wind turbines, this work contributes to a more detailed insight into noise from wind turbines. The study comprises analysis and interpretation of measurement data that were acquired during an experimental campaign involving a 2 MW...

  17. Characterization of ultra-fine grained steel samples produced by high pressure torsion via magnetic Barkhausen noise analysis

    International Nuclear Information System (INIS)

    High pressure torsion (HPT) is one of the most widely used severe plastic deformation methods which enable to obtain a crack-free ultra-fine grained bulk sample. In the process, a disk-shaped sample is pressed between two anvils and deformed via surface friction forces by rotating one of the anvils. The aim of this study is to nondestructively characterize the variations in the deformation uniformity of the severely deformed disks. Various sets of low carbon steel samples were obtained by applying the constrained HPT process up to 6 turns. Magnetic Barkhausen noise (MBN) method was used in order to evaluate the samples in a nondestructive manner via a commercial system. The results were compared with those of metallographic examination, hardness measurements and X-ray diffraction (XRD). The initial stages of HPT revealed the effects of conventional plastic deformation on MBN; however with further straining, grain refinement caused increase in MBN signals.

  18. Observation and characterization of flow in critical sections of a horizontal pressurized gating system using water models

    Directory of Open Access Journals (Sweden)

    Jaiganesh Venkataramani

    2013-07-01

    Full Text Available This work is concerned with the hydraulics and flow characterization in a pressurized, horizontal gating system with multiple ingates attached to a plate mold, using transparent water models. Runners with two different aspect ratios (w/h = 0.5 and 2 and four different types of ingates (rectangular, convergent, divergent and venturi were examined for their influence on flow behavior. Flow behavior was visualized using a high speed camera capable of capturing images up to 10,000 frames per second. Real time experimentation with a few runner – ingate combinations were carried out to validate the usefulness of water models in predicting the filling behavior. Comparison of the approaches provided useful insights into the filling behavior in critical sections of the flow passages as well as the utility of water models towards understanding of the filling behavior during real time casting.

  19. Characterization of UV-enhanced SiPMs for Imaging in High Pressure Xenon Electroluminescent TPC

    International Nuclear Information System (INIS)

    The possibility of recording charged particle tracks in an electro-luminescent xenon gas TPC is investigated using a SiPM-based tracking system, operated in the demonstrator prototype of the NEXT-100 ββ decay experiment. The tracks of the ββ0ν events from the decay of the 136Xe isotope have a distinctive topology, which allows their discrimination against single-electron events from the natural radioactivity that populates the region of interest of the neutrinoless decay in the ββ energy spectrum. Combined to the near-intrinsic energy resolution of the gaseous detector, this tracking capability provides a powerful background rejection tool for the search of the neutrinoless ββ decay aimed by the experiment. The NEXT-100 detector concepts and sensitivity and the first results of its demonstrator prototype are presented. The characterization studies relevant for the operation of UV-enhanced SiPMs used for imaging in an electro-luminescent TPC are reviewed. (authors)

  20. Characterization of the Relationship between Intracranial Pressure and Electroencephalographic Monitoring in Burst Suppressed Patients

    Science.gov (United States)

    Connolly, Mark; Vespa, Paul; Pouratian, Nader; Gonzalez, Nestor R.; Hu, Xiao

    2014-01-01

    Objective To characterize the relationship between ICP and EEG Methods Simultaneous ICP and EEG data were obtained from burst-suppressed patients and segmented by EEG bursts. Segments were categorized as increasing/decreasing and peak/valley to investigate relationship between ICP changes and EEG burst duration. A generalized ICP response was obtained by averaging all segments time-aligned at burst onsets. A vasodilatation index (VDI) was derived from the ICP pulse waveform and calculated on a sliding interval to investigate cerebrovascular changes post-burst. Results Data from two patients contained 309 bursts. 246 ICP segments initially increased, of which 154 peaked. 63 ICP segments decreased, and zero reached a valley. The change in ICP (0.54±0.85mmHg) was significantly correlated with the burst duration (pVDI for increasing segments was significantly elevated (median 0.56, IQR 0.31, p<0.001) and correlated with burst duration (p<0.001). Conclusions Changes in the ICP and pulse-waveform shape after EEG burst suggest that these signals can be related within the context of neurovascular coupling. Significance Existence of a physiological relationship between ICP and EEG may allow the study of neurovascular coupling in acute brain injury patients. PMID:25142827

  1. Experimental characterization of axillary/underarm interface pressure in swing-through crutch walking

    Directory of Open Access Journals (Sweden)

    James Borrelli, PhD

    2013-05-01

    Full Text Available Supporting weight on the upper support of crutches is not recommended because it can lead to axillary nerve damage. Despite this warning, improper axillary loadings may still occur because of a lack of arm strength or fatigue. It is generally accepted that improper use of conventional axillary crutches contributes to axillary nerve damage, but surprisingly there are no studies characterizing axillary support/underarm configurations. In this study, we compared traditional and horizontal axillary support designs by measuring various biomechanical parameters on the axillary support during a swing-through gait while supporting weight on the axillary support. Subjects found the axillary support that remains horizontal to be more comfortable than the axillary support of axillary crutches. The higher perceived comfort may be attributed to the lower force and contact area, both average and maximum, developed on the horizontal axillary support and/or shorter excursion of the position of the center of force during a stride. These findings suggest that avoiding all weight bearing on the axillary support may be an overly conservative recommendation for supports that remain horizontal. Individuals with insufficient arm strength may benefit by considering this type of support, but because further study is needed, a physical therapist should be consulted.

  2. Time-resolved characterization of a filamentary argon discharge at atmospheric pressure in a capillary using emission and absorption spectroscopy

    Science.gov (United States)

    Schröter, Sandra; Pothiraja, Ramasamy; Awakowicz, Peter; Bibinov, Nikita; Böke, Marc; Niermann, Benedikt; Winter, Jörg

    2013-11-01

    An argon/nitrogen (0.999/0.001) filamentary pulsed discharge operated at atmospheric pressure in a quartz tube is characterized using voltage-current measurements, microphotography, optical emission spectroscopy (OES) and absorption spectroscopy. Nitrogen is applied as a sensor gas for the purpose of OES diagnostic. The density of argon metastable atoms Ar(3P2) is determined using tunable diode laser absorption spectroscopy (TDLAS). Using a plasma chemical model the measured OES data are applied for the characterization of the plasma conditions. Between intense positive pulses the discharge current oscillates with a damped amplitude. It is established that an electric current flows in this discharge not only through a thin plasma filament that is observed in the discharge image but also through the whole cross section of the quartz tube. A diffuse plasma fills the quartz tube during a time between intense current pulses. Ionization waves are propagating in this plasma between the spike and the grounded area of the tube producing thin plasma channels. The diameter of these channels increases during the pause between the propagation of ionization waves probably because of thermal expansion and diffusion. Inside the channels electron densities of ˜2 × 1013 cm-3, argon metastable densities ˜1014 cm-3 and a reduced electric field about 10 Td are determined.

  3. Characterization of low-pressure microwave and radio frequency discharges in oxygen applying optical emission spectroscopy and multipole resonance probe

    International Nuclear Information System (INIS)

    Optical emission spectroscopy (OES) and multipole resonance probe (MRP) are adopted to characterize low-pressure microwave (MW) and radio frequency (RF) discharges in oxygen. In this context, both discharges are usually applied for the deposition of permeation barrier SiOx films on plastic foils or the inner surface of plastic bottles. For technological reasons the MW excitation is modulated and a continuous wave (cw) RF bias is used. The RF voltage produces a stationary low-density plasma, whereas the high-density MW discharge is pulsed. For the optimization of deposition process and the quality of the deposited barrier films, plasma conditions are characterized using OES and MRP. To simplify the comparison of applied diagnostics, both MW and RF discharges are studied separately in cw mode. The OES and MRP diagnostic methods complement each other and provide reliable information about electron density and electron temperature. In the MW case, electron density amounts to ne = (1.25 ± 0.26) × 1017 m−3, and kTe to 1.93 ± 0.20 eV, in the RF case ne = (6.8 ± 1.8)×1015 m−3 and kTe = 2.6 ± 0.35 eV. The corresponding gas temperatures are 760±40 K and 440±20 K. (paper)

  4. Athabasca oil sands process water: characterization by atmospheric pressure photoionization and electrospray ionization fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Barrow, Mark P; Witt, Matthias; Headley, John V; Peru, Kerry M

    2010-05-01

    The Athabasca oil sands in Canada are a less conventional source of oil which have seen rapid development. There are concerns about the environmental impact, with particular respect to components in oil sands process water which may enter the aquatic ecosystem. Naphthenic acids have been previously targeted for study, due to their implications in toxicity toward aquatic wildlife, but it is believed that other components, too, contribute toward the potential toxicity of the oil sands process water. When mass spectrometry is used, it is necessary to use instrumentation with a high resolving power and mass accuracy when studying complex mixtures, but the technique has previously been hindered by the range of compounds that have been accessible via common ionization techniques, such as electrospray ionization. The research described here applied Fourier transform ion cyclotron resonance mass spectrometry in conjunction with electrospray ionization and atmospheric pressure photoionization, in both positive-ion and negative-ion modes, to the characterization of oil sands process water for the first time. The results highlight the need for broader characterization when investigating toxic components within oil sands process water. PMID:20359201

  5. On the design and characterization of a new cold atmospheric pressure plasma jet and its applications on cancer cells treatment.

    Science.gov (United States)

    Akhlaghi, Morteza; Rajayi, Hajar; Mashayekh, Amir Shahriar; Khani, Mohammadreza; Hassan, Zuhair Mohammad; Shokri, Babak

    2015-01-01

    In this paper, a new configuration of a cold atmospheric pressure plasma jet has been designed and constructed. Poly-methyl-methacrylate was used as a new dielectric in this configuration which in comparison to other dielectrics is inexpensive, more resistant against break, and also more shapeable. Then, the plasma jet parameters such as plume temperature, rotational and vibrational temperatures, power, electrical behavior (voltage and current profile), electron density, and the produced reactive species were characterized. In order to determine the jet temperature and the amount of reactive species, effects of applied voltage, gas flow rate, and distance from the nozzle were studied. The power of the jet was specified using Lissajous curve approach. The plume temperature of the plasma jet was about the room temperature. Optical emission spectroscopy determined the type of reactive species, and also electron density and its corresponding plasma frequency (~6.4 × 10(13) cm(-3) and 4.52 × 10(11) Hz). Because of producing different reactive species, the device can be used in different applications, especially in plasma medicine. Thus, 4T1 cancer cells were treated using this plasma jet. The results showed that this plasma jet has a great potential to kill one of the most aggressive and resistant cancerous cell lines. PMID:25908593

  6. Characterization of boron nitride phase transformations in the Li–B–N system under high pressure and high temperature

    International Nuclear Information System (INIS)

    Highlights: • The characterization of cBN phase transformation in Li3N melt is revealed under HPHT. • A simultaneous precipitation and dissolution of cBN in Li3BN2 melt is proved. • The BN phase transition behaviors of Li3N–hBN and Li3N–cBN system is not equivalent. • The results provide a clue for further improvement of the quality of direct sintering of cubic boron nitride. - Abstract: The possible phase transformations of boron nitride in the Li–B–N system have been discussed by the chemical reactions of Li3N, hBN and cBN at the conditions of 5.0 GPa and 1300–1500 °C. The results of the reaction between Li3N and hBN shows that certain Li–B–N eutectic compound(s) which were produced in the thermodynamical stable region of cBN have no catalytic effect for cBN growth. It indicates that a certain irreversible BN precipitation/dissolution process takes place in Li3N melt. However, the reaction between Li3N and hBN is preferential when Li3N, hBN and cBN coexist in Li–B–N system, and the regrowth of cBN is observed, namely the morphology of cBN changing from irregular to fine shape crystals with well-facetted (1 1 1) surface. Furthermore, the estimated sizes of regrown cBN are almost same as those of the raw cBN. This indicates a simultaneous cBN dissolution and precipitation process in Li3N + hBN/cBN system under high pressure and high temperature

  7. Characterization of boron nitride phase transformations in the Li–B–N system under high pressure and high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Guo, W., E-mail: guowei1982cry@163.com [College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China); National Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China); Shi, Y. [College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Yang, P. [College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China); Ma, H.A.; Jia, X. [National Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China); Wang, S., E-mail: wangshuang@tyut.edu.cn [College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China)

    2015-09-25

    Highlights: • The characterization of cBN phase transformation in Li{sub 3}N melt is revealed under HPHT. • A simultaneous precipitation and dissolution of cBN in Li{sub 3}BN{sub 2} melt is proved. • The BN phase transition behaviors of Li{sub 3}N–hBN and Li{sub 3}N–cBN system is not equivalent. • The results provide a clue for further improvement of the quality of direct sintering of cubic boron nitride. - Abstract: The possible phase transformations of boron nitride in the Li–B–N system have been discussed by the chemical reactions of Li{sub 3}N, hBN and cBN at the conditions of 5.0 GPa and 1300–1500 °C. The results of the reaction between Li{sub 3}N and hBN shows that certain Li–B–N eutectic compound(s) which were produced in the thermodynamical stable region of cBN have no catalytic effect for cBN growth. It indicates that a certain irreversible BN precipitation/dissolution process takes place in Li{sub 3}N melt. However, the reaction between Li{sub 3}N and hBN is preferential when Li{sub 3}N, hBN and cBN coexist in Li–B–N system, and the regrowth of cBN is observed, namely the morphology of cBN changing from irregular to fine shape crystals with well-facetted (1 1 1) surface. Furthermore, the estimated sizes of regrown cBN are almost same as those of the raw cBN. This indicates a simultaneous cBN dissolution and precipitation process in Li{sub 3}N + hBN/cBN system under high pressure and high temperature.

  8. Characterization of Piezoresistive PEDOT:PSS Pressure Sensors with Inter-Digitated and Cross-Point Electrode Structures

    Directory of Open Access Journals (Sweden)

    Jer-Chyi Wang

    2015-01-01

    Full Text Available The piezoresistive characteristics of poly(3,4-ethylenedioxythiophene:polystyrene sulfonate (PEDOT:PSS pressure sensors with inter-digitated (IDE and cross-point electrode (CPE structures have been investigated. A small variation of the resistance of the pressure sensors with IDE without bottom indium-tin-oxide (b-ITO film and with CPE structures was observed owing to the single carrier-conducting pathway. For the IDE pressure sensors with b-ITO, the piezoresistive characteristics at low and high pressure were similar to those of the pressure sensors with IDE without b-ITO and with CPE structures, respectively, leading to increased piezoresistive pressure sensitivity as the PEDOT:PSS film thickness decreased. A maximum sensitivity of more than 42 kΩ/Pa was achieved. When the normal pressure was applied, the increased number of conducting points or the reduced distance between the PEDOT oligomers within the PEDOT:PSS film resulted in a decrease of the resistance. The piezoresistive pressure sensors with a single carrier-conducting pathway, i.e., IDE without b-ITO and CPE structures, exhibited a small relaxation time and a superior reversible operation, which can be advantageous for fast piezoresistive response applications.

  9. Screening foods for processing-resistant bacterial spores and characterization of a pressure- and heat-resistant Bacillus licheniformis isolate.

    Science.gov (United States)

    Ahn, Juhee; Balasubramaniam, V M

    2014-06-01

    This study was carried out to isolate pressure- and heat-resistant indicator spores from selected food matrices (black pepper, red pepper, garlic, and potato peel). Food samples were processed under various thermal (90 to 105°C) and pressure (700 MPa) combination conditions, and surviving microorganisms were isolated. An isolate from red pepper powder, Bacillus licheniformis, was highly resistant to pressure-thermal treatments. Spores of the isolate in deionized water were subjected to the combination treatments of pressure (0.1 to 700 MPa) and heat (90 to 121°C). Compared with the thermal treatment, the combined pressure-thermal treatments considerably reduced the numbers of B. licheniformis spores to less than 1.0 log CFU/g at 700 MPa plus 105°C and at 300 to 700 MPa plus 121°C. The inactivation kinetic parameters of the isolated B. licheniformis spores were estimated using linear and nonlinear models. Within the range of the experimental conditions tested, the pressure sensitivity (zP) of the spores decreased with increasing temperature (up to 121°C), and the temperature sensitivity (zT) was maximum at atmospheric pressure (0.1 MPa). These results will be useful for developing a combined pressure-thermal inactivation kinetics database for various bacterial spores. PMID:24853517

  10. Progress in evaluation and improvement in nondestructive examination reliability for inservice inspection of Light Water Reactors (LWRs) and characterize fabrication flaws in reactor pressure vessels

    International Nuclear Information System (INIS)

    This paper is a review of the work conducted under two programs. One (NDE Reliability Program) is a multi-year program addressing the reliability of nondestructive evaluation (NDE) for the inservice inspection (ISI) of light water reactor components. This program examines the reliability of current NDE, the effectiveness of evolving technologies, and provides assessments and recommendations to ensure that the NDE is applied at the right time, in the right place with sufficient effectiveness that defects of importance to structural integrity will be reliably detected and accurately characterized. The second program (Characterizing Fabrication Flaws in Reactor Pressure Vessels) is assembling a data base to quantify the distribution of fabrication flaws that exist in US nuclear reactor pressure vessels with respect to density, size, type, and location. These programs will be discussed as two separate sections in this report. 4 refs., 7 figs

  11. Thermal and Pressure Characterization of a Wind Tunnel Force Balance Using the Single Vector System. Experimental Design and Analysis Approach to Model Pressure and Temperature Effects in Hypersonic Wind Tunnel Research

    Science.gov (United States)

    Lynn, Keith C.; Commo, Sean A.; Johnson, Thomas H.; Parker, Peter A,

    2011-01-01

    Wind tunnel research at NASA Langley Research Center s 31-inch Mach 10 hypersonic facility utilized a 5-component force balance, which provided a pressurized flow-thru capability to the test article. The goal of the research was to determine the interaction effects between the free-stream flow and the exit flow from the reaction control system on the Mars Science Laboratory aeroshell during planetary entry. In the wind tunnel, the balance was exposed to aerodynamic forces and moments, steady-state and transient thermal gradients, and various internal balance cavity pressures. Historically, these effects on force measurement accuracy have not been fully characterized due to limitations in the calibration apparatus. A statistically designed experiment was developed to adequately characterize the behavior of the balance over the expected wind tunnel operating ranges (forces/moments, temperatures, and pressures). The experimental design was based on a Taylor-series expansion in the seven factors for the mathematical models. Model inversion was required to calculate the aerodynamic forces and moments as a function of the strain-gage readings. Details regarding transducer on-board compensation techniques, experimental design development, mathematical modeling, and wind tunnel data reduction are included in this paper.

  12. Experimental Study of Abiotic Organic Synthesis at High Temperature and Pressure Conditions: Carbon Isotope and Mineral Surface Characterizations

    Science.gov (United States)

    Fu, Qi; Socki, R. A.; Niles, P. B.

    2010-01-01

    Abiotic organic synthesis processes have been proposed as potential mechanisms for methane generation in subseafloor hydrothermal systems on Earth, and on other planets. To better understand the detailed reaction pathways and carbon isotope fractionations in this process under a wide range of physical and chemical conditions, hydrothermal experiments at high temperature (750 C) and pressure (0.55 GPa) were performed using piston cylinder apparatus. Formic acid was used as the source of CO2 and H2, and magnetite was the mineral catalyst. The chemical and carbon isotopic compositions of dissolved organic products were determined by GC-C-MS-IRMS, while organic intermediaries on the mineral catalyst were characterized by Pyrolysis-GC-MS. Among experimental products, dissolved CO2 was the dominant carbon species with a relative abundance of 88 mol%. Dissolved CH4 and C2H6 were also identified with a mole ratio of CH4 over C2H6 of 15:1. No dissolved CO was detected in the experiment, which might be attributable to the loss of H2 through the Au capsule used in the experiments at high temperature and pressure conditions and corresponding conversion of CO to CO2 by the water-gas shift reaction. Carbon isotope results showed that the 13C values of CH4 and C2H6 were -50.3% and -39.3% (V-PDB), respectively. CO2 derived from decarboxylation of formic acid had a (sigma)C-13 value of -19.2%, which was 3.2% heavier than its source, formic acid. The (sigma)C-13 difference between CO2 and CH4 was 31.1%, which was higher than the value of 9.4% calculated from theoretical isotopic equilibrium predictions at experimental conditions, suggesting the presence of a kinetic isotope effect. This number was also higher than the values (4.6 to 27.1%) observed in similar experiments previously performed at 400 C and 50 MPa with longer reaction times. CH4 is 11.0% less enriched in C-13 than C2H6. Alcohols were observed as carbon compounds on magnetite surfaces by Pyrolysis-GC-MS, which confirms

  13. Microstructural characterization and process selection by attributive analysis of eutectic and quasi-eutectic Al-Si alloys for pressure die casting

    OpenAIRE

    Suárez-Peña, B.; Asensio-Lozano, J.; Verdeja-González, J. I.; Pero-Sanz Elorz, J. A.

    2007-01-01

    In the present study, four alloys from diverse suppliers suitable for obtaining 413.0 metallurgical quality products together with alloy number 2 with an slightly hypoeutectic composition in Silicon were processed. The study focused on the microstructural characterization of the as-received ingots, as well as that of samples obtained from the production process: die cast samples and cold chamber pressure die cast samples. Finally a materials selection process base on microstructural grounds h...

  14. High-temperature, high-pressure hydrothermal synthesis, characterization, and structural relationships of mixed-alkali metals uranyl silicates

    Science.gov (United States)

    Chen, Yi-Hsin; Liu, Hsin-Kuan; Chang, Wen-Jung; Tzou, Der-Lii; Lii, Kwang-Hwa

    2016-04-01

    Three mixed-alkali metals uranyl silicates, Na3K3[(UO2)3(Si2O7)2]·2H2O (1), Na3Rb3[(UO2)3(Si2O7)2] (2), and Na6Rb4[(UO2)4Si12O33] (3), have been synthesized by high-temperature, high-pressure hydrothermal reactions at 550 °C and 1440 bar, and characterized by single-crystal X-ray diffraction, photoluminescence, and thermogravimetric analysis. Compound 1 and 2 are isostructural and contain layers of uranyl disilicate. The smaller cation, Na+, is located in the intralayer channels, whereas the larger cations, K+ and Rb+, and water molecule are located in the interlayer region. The absence of lattice water in 2 can be understood according to the valence-matching principle. The structure is related to that of a previously reported mixed-valence uranium(V,VI) silicate. Compound 3 adopts a 3D framework structure and contains a unique unbranched dreier fourfold silicate chain with the structural formula {uB,41∞}[3Si12O33] formed of Q2, Q3, and Q4 Si. The connectivity of the Si atoms in the Si12O3318- anion can be interpreted on the basis of Zintl-Klemm concept. Crystal data for compound 1: triclinic, P-1, a=5.7981(2) Å, b=7.5875(3) Å, c=12.8068(5) Å, α=103.593(2)°, β=102.879(2)°, γ=90.064(2)°, V=533.00(3) Å3, Z=1, R1=0.0278; compound 2: triclinic, P-1, a=5.7993(3) Å, b=7.5745(3) Å, c=12.9369(6) Å, α=78.265(2)°, β=79.137(2)°, γ=89.936(2)°, V=546.02(4) Å3, Z=1, R1=0.0287; compound 3: monoclinic, C2/m, a=23.748(1) Å, b=7.3301(3) Å, c=15.2556(7) Å, β=129.116(2)°, V=2060.4(2) Å3, Z=2, R1=0.0304.

  15. Atom probe tomography characterization of neutron irradiated surveillance samples from the R. E. Ginna reactor pressure vessel

    International Nuclear Information System (INIS)

    Surveillance samples of a low copper (nominally 0.05 wt.% Cu) forging and a higher copper (0.23 wt.% Cu) submerged arc weld from the R. E. Ginna reactor pressure vessel have been characterized by atom probe tomography (APT) after exposure to three levels of neutron irradiation, i.e., fluences of 1.7, 3.6 and 5.8 x 1023 n.m-2 (E > 1 MeV), and inlet temperatures of ~289 °C (~552 °F). As no copper-enriched precipitates were observed in the low copper forging, and the measured copper content in the ferrite matrix was 0.04± <0.01 at.% Cu, after neutron irradiation to a fluence of 1.7 x 1023 n.m-3, this copper level was below the solubility limit. A number density of 2 x 1022 m-3 of Ni-, Mn- Si-enriched precipitates with an equivalent radius of gyration of 1.7 ± 0.4 nm were detected in the sample. However, Cu-, Ni-, Mn-enriched precipitates were observed in specimens cut from different surveillance specimens from the same forging material in which the overall measured copper level was 0.08± <0.01 at.% (fluence of 3.6 x 1023 n.m-3) and 0.09± <0.01 at.% Cu (fluence of 5.8 x 1023 n.m-3). Therefore, these slightly higher copper contents were above the solubility limit of Cu under these irradiation conditions. A best fit of all the composition data indicated that the size and number density of the Cu-enriched precipitates increased slightly in both size and number density by additional exposure to neutron irradiation. High number densities of Cu-enriched precipitates were observed in the higher Cu submerged arc weld for all irradiated conditions. The size and number density of the precipitates in the welds were higher than in the same fluence forgings. Some Cu-enriched precipitates were found to have Ni-, Mn- Si-, and P-enriched regions on their surfaces suggesting a preferential nucleation site. Furthermore, atom maps revealed P, Ni, and Mn segregation to, and preferential precipitation of, Cu-enriched precipitates over the surface of a grain boundary in the low

  16. Characterization of the TiSiO4 structure and its pressure-induced phase transformations: density functional theory study

    OpenAIRE

    Gracia Edo, Lourdes; Beltrán Flors, Armando; Errandonea, Daniel

    2009-01-01

    Theoretical investigations concerning the possible titanium silicate polymorphs have been performed using density functional theory at B3LYP level. Total-energy calculations and geometry optimizations have been carried out for all phases involved. The following sequence of pressure-driven structural transitions has been found: CrVO4 -type, Cmcm in parenthesis the transition pressure , → zircon-type, I41 / amd 0.8 GPa , → scheelite-type, I41 / a 3.8 GPa . At higher pres...

  17. High-pressure characterization of nitrogen-rich bis-triaminoguanidinium azotetrazolate (TAGzT) by in situ Raman spectroscopy.

    Science.gov (United States)

    Behler, K D; Ciezak-Jenkins, J A; Sausa, R C

    2013-02-28

    Compounds rich in nitrogen are attracting significant interest not only because of their high energy content but also because they are potentially more environmentally benign in comparison to conventional energetic materials. Given this interest, it is desirable to understand their molecular composition and structural variations with pressure to derive their stability and determine the conditions in which they transform physically or chemically. In this study, we examine the room-temperature isothermal compression behavior of bis-triaminoguanidinium azotetrazolate (TAGzT) by in situ Raman spectroscopy to pressures near 17 GPa. We assign the characteristic vibrational bands and report the effects of pressure on band intensity, line width, and frequency shift. Two prominent peaks near 1370 and 1470 cm(-1) arise from the C-N and N═N symmetric stretches, respectively. Overall, the intensity of these bands and others diminishes with pressure, and their spectral linewidths increase monotonically upon compression. The vibrational frequency modes blue shift linearly upon compression, indicating a generalized stiffening of the bonds as the pressure increases. These results, together with micro Raman spectroscopic analyses of the recovered, decompressed samples, suggest that TAGzT does not undergo any phase transitions within this pressure range. We estimate and report the C-N and N═N intermolecular bond lengths under compression. PMID:23343336

  18. Simultaneous Photonic Doppler Velocimetry and Ultra-high Speed Imaging Techniques to Characterize Pressure Output of Detonators

    Science.gov (United States)

    Murphy, Michael; Clarke, Steven

    2011-06-01

    Detonator output directed into both ambient air and polymethylmethacrylate (PMMA) samples is simultaneously investigated using ultra-high speed, time-resolved schlieren/shadowgraph imaging and photonic Doppler velocimetry (PDV) measurements. In air, one-dimensional measurements of explosive cup position are made from the time-resolved image sequences and are compared to time-integrated velocity curves obtained from the PDV data. The results demonstrate good agreement that validates using the two methods concurrently. In PMMA, both average and instantaneous shock velocities are calculated from 1-D measurements of shock position. Velocity-Hugoniot data for PMMA is utilized to map the shock velocity calculations to corresponding values of mass velocity and shock pressure. Simultaneous PDV data describing the motion of the explosive cup/PMMA interface is used to determine the mass velocity and pressure at the interface, and to compare to the mass and shock pressures calculated from the imaging data.

  19. Preparation and Characterization of Refuse Derived Fuel for Pyrolysis and Gasification by Bindless High Pressure Briquetting Technology

    Institute of Scientific and Technical Information of China (English)

    张宪生; 解强; 厉伟; 沈吉敏

    2004-01-01

    A new type of refuse derived fuel (RDF) for pyrolysis and gasification was prepared from municipal solid waste (MSW) in the presence of a small quantity of coal by bindless high pressure technology at room temperature. The physicochemical property of RDF was tested. Orthogonal experiment method was used to optimize the process parameters using dropping strength (mechanical strength) and thermal stability of the RDF as indices for quality of RDF. The result shows that the mixture of MSW and coal with a total moisture ranging from 5% to 17% can be easily compressed into RDF briquettes at a pressure above 70 MPa. When the briquetting pressure is higher than 100 kN and moisture content is about 10%, the qualified RDF can be obtained. The orthogonal experiment shows that the moisture can greatly affect the mechanical strength of RDF, while all the technique parameters have no obvious influence on thermal stability of RDF. The optimal parameters are a shaping pressure of 106 MPa, a moisture content of 10%, and a coal content of 20%.

  20. Design, fabrication and characterization of a high-sensitivity pressure sensor based on nano-polysilicon thin film transistors

    Directory of Open Access Journals (Sweden)

    Xiaofeng Zhao

    2015-12-01

    Full Text Available Based on the nano-polysilicon thin film transistors (TFTs, a high-sensitivity pressure sensor was designed and fabricated in this paper. The pressure sensing element is composed of a Wheatstone bridge with four nano-polysilicon TFTs designed on different positions of the square silicon diaphragm. Via taking the four channel resistors of the TFTs as piezoresistors, the measurement to the external pressure can be realized according to the piezoresistive effects of channel layer. Through adopting complementary metal oxide semiconductor (CMOS technology and micro-electromechanical system (MEMS technology, the chips of sensor were fabricated on orientation silicon wafer with a high resistivity. At room temperature, when applying a voltage 5.0 V to the Wheatstone bridge, the full scale (100 kPa output voltage and the sensitivity of the sensor with 35 μm-thick silicon diaphragm are 267 mV and 2.58 mV/kPa, respectively. The experimental results show that the pressure sensors can achieve a much higher sensitivity.

  1. Mechanical and thermal property characterization of poly-L-lactide (PLLA) scaffold developed using pressure-controllable green foaming technology

    International Nuclear Information System (INIS)

    Poly-L-lactide (PLLA) is one of the most promising biological materials used for tissue engineering scaffolds (TES) because of their excellent biodegradability and tenability. Here, microcellular PLLA foams were fabricated by pressure-controllable green foaming technology. Scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), wide angle X-ray diffraction measurement (WAXRD), thermogravimetric (TG) analysis, reflection-Fourier transform infrared (FTIR) analysis, enzymatic degradation study and MTT assay were used to analyze the scaffolds' morphologies, structures and crystallinities, mechanical and biodegradation properties, as well as their cytotoxicity. The results showed that PLLA foams with pore sizes from 8 to 103 μm diameters were produced when the saturation pressure decreased from 7.0 to 4.0 MPa. Through a combination of StepScan DSC (SSDSC) and WAXRD approaches, it was observed in PLLA foams that the crystallinity, highly-oriented metastable state and rigid amorphous phase increased with the increasing foaming pressure. It was also found that both the glass transition temperature and apparent enthalpy of PLLA significantly increased after the foaming process, which suggested that the changes of microcellular structure could provide PLLA scaffolds better thermal stability and elasticity. Moreover, MTT assessments suggested that the smaller pore size should benefit cell attachment and growth in the scaffold. The results of current work will give us better understanding of the mechanisms involved in structure and property changes of PLLA at the molecular level, which enables more possibilities for the design of PLLA scaffold to satisfy various requirements in biomedical and green chemical applications. - Highlights: • Pressure-controllable green foaming technology is used. • The crystallinity and rigid amorphous fraction is calculated by using DSC and XRD. • We examine the changes of

  2. Mechanical and thermal property characterization of poly-L-lactide (PLLA) scaffold developed using pressure-controllable green foaming technology

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Shen-Jun [Center of Analysis and Testing, Nanjing Normal University, Nanjing 210023 (China); School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023 (China); Hu, Xiao [Department of Physics and Astronomy, Rowan University, Glassboro, NJ 08028 (United States); Department of Biomedical and Translational Sciences, Rowan University, Glassboro, NJ 08028 (United States); Wang, Fang, E-mail: wangfang@njnu.edu.cn [Center of Analysis and Testing, Nanjing Normal University, Nanjing 210023 (China); Department of Physics and Astronomy, Rowan University, Glassboro, NJ 08028 (United States); Ma, Qing-Yu [Key Laboratory of Optoelectronics of Jiangsu Province, School of Physics and Technology, Nanjing Normal University, Nanjing 210023 (China); Gu, Min-Fen [Center of Analysis and Testing, Nanjing Normal University, Nanjing 210023 (China)

    2015-04-01

    Poly-L-lactide (PLLA) is one of the most promising biological materials used for tissue engineering scaffolds (TES) because of their excellent biodegradability and tenability. Here, microcellular PLLA foams were fabricated by pressure-controllable green foaming technology. Scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), wide angle X-ray diffraction measurement (WAXRD), thermogravimetric (TG) analysis, reflection-Fourier transform infrared (FTIR) analysis, enzymatic degradation study and MTT assay were used to analyze the scaffolds' morphologies, structures and crystallinities, mechanical and biodegradation properties, as well as their cytotoxicity. The results showed that PLLA foams with pore sizes from 8 to 103 μm diameters were produced when the saturation pressure decreased from 7.0 to 4.0 MPa. Through a combination of StepScan DSC (SSDSC) and WAXRD approaches, it was observed in PLLA foams that the crystallinity, highly-oriented metastable state and rigid amorphous phase increased with the increasing foaming pressure. It was also found that both the glass transition temperature and apparent enthalpy of PLLA significantly increased after the foaming process, which suggested that the changes of microcellular structure could provide PLLA scaffolds better thermal stability and elasticity. Moreover, MTT assessments suggested that the smaller pore size should benefit cell attachment and growth in the scaffold. The results of current work will give us better understanding of the mechanisms involved in structure and property changes of PLLA at the molecular level, which enables more possibilities for the design of PLLA scaffold to satisfy various requirements in biomedical and green chemical applications. - Highlights: • Pressure-controllable green foaming technology is used. • The crystallinity and rigid amorphous fraction is calculated by using DSC and XRD. • We examine the changes of

  3. Mechanical and microstructural characterization of a HMX-based pressed explosive: Effects of combined high pressure and strain rate

    Directory of Open Access Journals (Sweden)

    Biessy M.

    2012-08-01

    Full Text Available The paper presents a study of the combined effects of strain rate and confining pressure on the behaviour and microstructure evolutions of a HMX-based explosive. Hopkinson bar compression experiments are carried-out on samples confined with a brass sleeve. The latter is instrumented in order to determine the confining pressure on the explosive sample, directly function of the sleeve thickness and yield strength. A sample confined at 75 MPa and deformed at 250s−1 is recovered, cross-sectioned and studied using optical microscopy. Distributed microplasticity and microcracking appear similar to those induced by confined quasi-static experiments, indicating that stress triaxiality is the most important loading parameter. The sample also displays a large shear macrocrack, resulting from the formation of an adiabatic shear band. Shear banding seems to proceed by strong plastic strain gradients, followed by dynamic re-crystallization. Further strong thermal effects are observed, resulting in local reactive melting.

  4. Characterization of elastic properties of Zr-2.5% Nb pressure tube by measurements of sound velocity

    International Nuclear Information System (INIS)

    The cold-worked Zr-2.5% Nb alloy is used as material for the pressure tubes of CANDU (CANadian Deuterium Uranium) nuclear reactors. During the service life in reactor, diffusion of hydrogen and/or deuterium in the pressure tubes wall will occur. Below a certain temperature, a stable hydride of zirconium will form, as a brittle phase which could lead to catastrophic failure. In the present paper, the influence of hydrogen on the acoustic-elastic properties of Zr-2.5% Nb alloy will be investigated using non-destructive method based on measurements of ultrasonic velocity. In order to obtain the most usual elastic coefficients on a given direction (axial and circumferential) of the tube, both longitudinal VL and transversal VT phase velocities have been experimentally determined. (authors)

  5. Characterization of bio-inspired hair flow sensors for oscillatory airflows: techniques to measure the response for both flow and pressure

    International Nuclear Information System (INIS)

    Hair sensors for oscillatory airflow, operating in the regime of bulk flow, particle velocity or both, can be characterized by several methods. In this work, we discuss harmonic measurements on MEMS hair flow sensors. To characterize this type of flow sensor the use of three different types of oscillatory airflow source is investigated. A loudspeaker, a vibrating sphere and a standing wave tube all have specific characteristics regarding their acoustic field, frequency range, maximum velocity amplitude and the possibility to chose the ratio between pressure and flow velocity. They are compared and an overview is given with respect to which source is the most appropriate under specific conditions. Furthermore, by combining information from the flow setups used new insights into sensor operation can be gained. (paper)

  6. Low-pressure solvent extraction of oil from macauba (Acrocomia aculeata) pulp: characterization of oil and defatted meal

    OpenAIRE

    Caroline Portilho Trentini; Dalany Menezes Oliveira; Cristina Maria Zanette; Camila da Silva

    2015-01-01

    ABSTRACT: This study aimed to extract the oil from macauba pulp using a low-pressure solvent extraction, as well as characterisation of the extracts and defatted meal obtained using different solvents (n-hexane, ethyl acetate and isopropanol). Results reported higher yields in oil, 27.43%, using isopropanol (P0.05) on the composition; however, in the quantification of free glycerol compounds, isopropanol showed higher levels, 104.15mg 100g-1, of these compounds (P

  7. Characterization and transformation of polyamide and polyepoxyde reactive systems formulated for rotomolded liners of high pressure storage

    OpenAIRE

    Lecocq, Eva

    2012-01-01

    The aim of this present study is to develop efficient and processable formulations for the liners of high pressure storage tank. A wide range of formulations based on polyamide and polyepoxide has been synthesized under controlled conditions representative of the rotomolding process. The polyamide system has been modified by copolymerization and the polyepoxyde system by a micro- or nano-structured dispersed phase with high Tg thermoplastics or block copolymers. The morphological, thermal, me...

  8. Magnetic characterization of non-ideal single-domain monoclinic pyrrhotite and its demagnetization under hydrostatic pressure up to 2 GPa with implications for impact demagnetization

    Science.gov (United States)

    Bezaeva, Natalia S.; Chareev, Dmitriy A.; Rochette, Pierre; Kars, Myriam; Gattacceca, Jérôme; Feinberg, Joshua M.; Sadykov, Ravil A.; Kuzina, Dilyara M.; Axenov, Sergey N.

    2016-08-01

    Here we present a comprehensive magnetic characterization of synthesized non-ideal single-domain (SD) monoclinic pyrrhotite (Fe7S8). The samples were in the form of a powder and a powder dispersed in epoxy. "Non-ideal" refers to a powder fraction of predominantly SD size with a minor contribution of small pseudo-single-domain grains; such non-ideal SD pyrrhotite was found to be a remanence carrier in several types of meteorites (carbonaceous chondrites, SNC…), which justifies the usage of synthetic compositions as analogous to natural samples. Data were collected from 5 to 633 K and include low-field magnetic susceptibility (χ0), thermomagnetic curves, major hysteresis loops, back-field remanence demagnetization curves, first-order reversal curves (FORCs), alternating field and pressure demagnetization of saturation isothermal remanent magnetization (SIRM), low temperature data (such as zero-field-cooled and field-cooled remanence datasets together with room temperature SIRM cooling-warming cycles) as well as XRD and Mössbauer spectra. The characteristic Besnus transition is observed at ∼33 K. FORC diagrams indicate interacting SD grains. The application of hydrostatic pressure up to 2 GPa using nonmagnetic high-pressure cells resulted in the demagnetization of the sample by 32-38%. Repeated cycling from 1.8 GPa to atmospheric pressure and back resulted in a total remanence decrease of 44% (after 3 cycles). Pressure demagnetization experiments have important implications for meteorite paleomagnetism and suggest that some published paleointensities of meteorites with non-ideal SD monoclinic pyrrhotite as remanence carrier may be lower limits because shock demagnetization was not accounted for.

  9. Characterization of W/Fe functionally graded materials manufactured by resistance sintering under ultra-high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Dandan [School of Materials Science and Engineering, University of Science and Technology Beijing, 100083 Beijing (China); Karlsruhe Institute of Technology, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Zhou, Zhangjian, E-mail: zhouzhangjianustb@163.com [School of Materials Science and Engineering, University of Science and Technology Beijing, 100083 Beijing (China); Tan, Jun [School of Materials Science and Engineering, University of Science and Technology Beijing, 100083 Beijing (China); Aktaa, Jarir [Karlsruhe Institute of Technology, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2015-02-15

    Highlights: • W/Fe functionally graded material (FGM) are fabricated well by resistance sintering under ultra-high pressure (RSUHP). • The whole sintering time is less than 3 min and cost-effective. • We research the W/Fe interface and the formation of intermetallic at the interface. In addition, we explain the possible method to avoid the formation of brittle intermetallic. • Vickers hardness of W/Fe FGM before and after heat treatment are investigated here. - Abstract: W/Fe-based components are considered as primary structural materials for the future fusion reactor. A five-layer W/Fe functional graded material (FGM) with W volume fraction of 0%, 25%, 50%, 75% and 100%, respectively, have been fabricated by a novel sintering method combining resistance sintering with ultra-high pressure. The sintering was carried out under pressures of 9 GPa and an input power of 11 kW for 60 s. The microstructure of cross-section observed by SEM shows a well-graded transition. The relative density of each layer is more than 97%. A brittle phase Fe{sub 7}W{sub 6} is formed at the interface of W particles and Fe particles, and this intermetallic phase coats Fe particles homogeneously with a thickness of 1–5 μm. It is possible to avoid the brittle phase by choosing appropriate particle size and sintering parameters. In addition, Vickers hardness of W/Fe FGM was investigated before and after heat treatment.

  10. Characterization of W/Fe functionally graded materials manufactured by resistance sintering under ultra-high pressure

    International Nuclear Information System (INIS)

    Highlights: • W/Fe functionally graded material (FGM) are fabricated well by resistance sintering under ultra-high pressure (RSUHP). • The whole sintering time is less than 3 min and cost-effective. • We research the W/Fe interface and the formation of intermetallic at the interface. In addition, we explain the possible method to avoid the formation of brittle intermetallic. • Vickers hardness of W/Fe FGM before and after heat treatment are investigated here. - Abstract: W/Fe-based components are considered as primary structural materials for the future fusion reactor. A five-layer W/Fe functional graded material (FGM) with W volume fraction of 0%, 25%, 50%, 75% and 100%, respectively, have been fabricated by a novel sintering method combining resistance sintering with ultra-high pressure. The sintering was carried out under pressures of 9 GPa and an input power of 11 kW for 60 s. The microstructure of cross-section observed by SEM shows a well-graded transition. The relative density of each layer is more than 97%. A brittle phase Fe7W6 is formed at the interface of W particles and Fe particles, and this intermetallic phase coats Fe particles homogeneously with a thickness of 1–5 μm. It is possible to avoid the brittle phase by choosing appropriate particle size and sintering parameters. In addition, Vickers hardness of W/Fe FGM was investigated before and after heat treatment

  11. Towards a reference cavitating vessel Part III—design and acoustic pressure characterization of a multi-frequency sonoreactor

    Science.gov (United States)

    Wang, Lian; Memoli, Gianluca; Hodnett, Mark; Butterworth, Ian; Sarno, Dan; Zeqiri, Bajram

    2015-08-01

    A multi-frequency cavitation vessel (RV-multi) has been commissioned at the National Physical Laboratory (NPL, UK), with the aim of establishing a standard source of acoustic cavitation in water, with reference to which details of the cavitation process can be studied and cavitation measurement techniques evaluated. The vessel is a cylindrical cavity with a maximum capacity up to 17 L, and is designed to work at six frequency ranges, from 21 kHz to 136 kHz, under controlled temperature conditions. This paper discusses the design of RV-multi and reports experiments carried out to establish the reproducibility of the acoustic pressure field established within the vessel and its operating envelope, including sensitivity to aspects such as water depth and temperature. The acoustic field distribution was determined along the radial and depth directions within the vessel using a miniature hydrophone, for two input voltage levels under low power transducer excitation conditions (e.g. below the cavitation threshold). Particular care was taken in determining peak acoustic pressure locations, as these are critical for accompanying cavitation studies. Perturbations of the vessel by the measuring hydrophone were also monitored with a bottom-mounted pressure sensor.

  12. Simultaneous photonic doppler velocimetry and ultra-high speed imaging techniques to characterize the pressure output of detonators

    Science.gov (United States)

    Murphy, Michael; Clarke, Steven A.

    2012-03-01

    Detonator output directed into both ambient air and polymethylmethacrylate (PMMA) windows is simultaneously investigated using ultra-high speed, time-resolved imaging and photonic Doppler velocimetry (PDV) measurements. In air, one-dimensional measurements of detonator cup position are made from timeresolved image sequences and compared to time-integrated velocity curves obtained from the PDV data. The results demonstrate good agreement that validates using the two methods concurrently to measure the motion of the detonator free-surface. In PMMA windows, instantaneous shock velocities are calculated from 1-D time-resolved measurements of shock position and known velocity-Hugoniot data are utilized to map the shock velocity calculations to corresponding values of mass velocity and shock pressure. Simultaneous PDV data describing the motion of the detonator cup/PMMA interface are used to determine the mass velocity and pressure at the interface, and to compare to the mass and shock pressures calculated from the imaging data. Experimental results are in good agreement with empirical detonation- and shock-interaction calculations, as well as 1-D numerical simulations.

  13. On-line characterization of gaseous and particulate organic analytes using atmospheric pressure chemical ionization mass spectrometry

    International Nuclear Information System (INIS)

    A modified atmospheric pressure chemical ionization ion source is applied for direct analysis of volatile or low volatile organic compounds in air. The method is based on the direct introduction of the analytes in the gas phase and/or particle phase into the ion source of a commercial ion-trap mass spectrometer. Two methods are employed for the production of primary ions at atmospheric pressure, photoionization and corona discharge. It is shown that in the presence of a dopant, photoionization can be a highly efficient ionization method also for real-time analysis with detection limits for selected analytes in the lower ppt-range. Using corona discharge for the production of primary ions, which is instrumentally easier since no additional chemicals have to be added to the sample flow, we demonstrate the analytical potential of on-line atmospheric pressure chemical ionization mass spectrometry for reaction monitoring experiments. To do so, an atmospherically relevant gas phase reaction is carried out in a 500 l reaction chamber and gaseous and particulate compounds are monitored in the positive and negative ion mode of the mass spectrometer

  14. Space Shuttle Main Engine Low Pressure Oxidizer Turbo-Pump Inducer Dynamic Environment Characterization through Water Model and Hot-Fire Testing

    Science.gov (United States)

    Arellano, Patrick; Patton, Marc; Schwartz, Alan; Stanton, David

    2006-01-01

    The Low Pressure Oxidizer Turbopump (LPOTP) inducer on the Block II configuration Space Shuttle Main Engine (SSME) experienced blade leading edge ripples during hot firing. This undesirable condition led to a minor redesign of the inducer blades. This resulted in the need to evaluate the performance and the dynamic environment of the redesign, relative to the current configuration, as part of the design acceptance process. Sub-scale water model tests of the two inducer configurations were performed, with emphasis on the dynamic environment due to cavitation induced vibrations. Water model tests were performed over a wide range of inlet flow coefficient and pressure conditions, representative of the scaled operating envelope of the Block II SSME, both in flight and in ground hot-fire tests, including all power levels. The water test hardware, facility set-up, type and placement of instrumentation, the scope of the test program, specific test objectives, data evaluation process and water test results that characterize and compare the two SSME LPOTP inducers are discussed. In addition, dynamic characteristics of the two water models were compared to hot fire data from specially instrumented ground tests. In general, good agreement between the water model and hot fire data was found, which confirms the value of water model testing for dynamic characterization of rocket engine turbomachinery.

  15. Performance and Facility Background Pressure Characterization Tests of NASAs 12.5-kW Hall Effect Rocket with Magnetic Shielding Thruster

    Science.gov (United States)

    Kamhawi, Hani; Huang, Wensheng; Haag, Thomas; Shastry, Rohit; Thomas, Robert; Yim, John; Herman, Daniel; Williams, George; Myers, James; Hofer, Richard; Mikellides, Ioannis; Sekerak, Michael; Polk, James

    2015-01-01

    NASA's Space Technology Mission Directorate (STMD) Solar Electric Propulsion Technology Demonstration Mission (SEP/TDM) project is funding the development of a 12.5-kW Hall thruster system to support future NASA missions. The thruster designated Hall Effect Rocket with Magnetic Shielding (HERMeS) is a 12.5-kW Hall thruster with magnetic shielding incorporating a centrally mounted cathode. HERMeS was designed and modeled by a NASA GRC and JPL team and was fabricated and tested in vacuum facility 5 (VF5) at NASA GRC. Tests at NASA GRC were performed with the Technology Development Unit 1 (TDU1) thruster. TDU1's magnetic shielding topology was confirmed by measurement of anode potential and low electron temperature along the discharge chamber walls. Thermal characterization tests indicated that during full power thruster operation at peak magnetic field strength, the various thruster component temperatures were below prescribed maximum allowable limits. Performance characterization tests demonstrated the thruster's wide throttling range and found that the thruster can achieve a peak thruster efficiency of 63% at 12.5 kW 500 V and can attain a specific impulse of 3,000 s at 12.5 kW and a discharge voltage of 800 V. Facility background pressure variation tests revealed that the performance, operational characteristics, and magnetic shielding effectiveness of the TDU1 design were mostly insensitive to increases in background pressure.

  16. Plantar ROI Characterization during the Stance Phase of Gait Based on a Low-cost Pressure Acquisition Platform

    Institute of Scientific and Technical Information of China (English)

    Zhanyong Mei; Guoru Zhao; Qingsong Zhu; Lei Wang

    2012-01-01

    Plantar Region of Interest (ROI) detection is important for the early diagnosis and treatment of morphologic defects of the foot and foot bionic research.Conventional methods have employed complex procedures and expensive instruments which prohibit their widespread use in healthcare.In this paper an automatic plantar ROIs detection method using a customized low-cost pressure acquisition device is proposed.Plantar pressure data and 3D motion capture data were collected from 28subjects (14 healthy subjects and 14 subjects with hallux valgus).The maximal inter-frame difference during the stance phase was calculated.Consequently,the ROIs were defined by the first-order difference in combination with prior anatomic knowledge.The anatomic locations were determined by the maximal inter-frame difference and second maximal inter-frame difference,which nearly coincided.Our system can achieve average recognition accuracies of 92.90%,89.30%,89.30%,92.90%,92.90%,and 89.30% for plantar ROIs hallux and metatarsi Ⅰ-Ⅴ,respectively,as compared with the annotations using the 3Dmotion capture system.The maximal difference of metatarsus heads Ⅱ-Ⅴ,and the impulse of the medial and lateral heel features made a significant contribution to the classification of hallux valgus and healthy subjects with ≥ 80% sensitivity and specificity.Furthermore,the plantar pressure acquisition system is portable and convenient to use,thus can be used in home- or community-based healthcare applications.

  17. Characterization of the Ignition Over-Pressure/Sound Suppression Water in the Space Launch System Mobile Launcher Using Volume of Fluid Modeling

    Science.gov (United States)

    West, Jeff

    2015-01-01

    The Space Launch System (SLS) Vehicle consists of a Core Stage with four RS-25 engines and two Solid Rocket Boosters (SRBs). This vehicle is launched from the Launchpad using a Mobile Launcher (ML) which supports the SLS vehicle until its liftoff from the ML under its own power. The combination of the four RS-25 engines and two SRBs generate a significant Ignition Over-Pressure (IOP) and Acoustic Sound environment. One of the mitigations of these environments is the Ignition Over-Pressure/Sound Suppression (IOP/SS) subsystem installed on the ML. This system consists of six water nozzles located parallel to and 24 inches downstream of each SRB nozzle exit plane as well as 16 water nozzles located parallel to and 53 inches downstream of the RS-25 nozzle exit plane. During launch of the SLS vehicle, water is ejected through each water nozzle to reduce the intensity of the transient pressure environment imposed upon the SLS vehicle. While required for the mitigation of the transient pressure environment on the SLS vehicle, the IOP/SS subsystem interacts (possibly adversely) with other systems located on the Launch Pad. One of the other systems that the IOP/SS water is anticipated to interact with is the Hydrogen Burn-Off Igniter System (HBOI). The HBOI system's purpose is to ignite the unburned hydrogen/air mixture that develops in and around the nozzle of the RS-25 engines during engine start. Due to the close proximity of the water system to the HBOI system, the presence of the IOP/SS may degrade the effectiveness of the HBOI system. Another system that the IOP/SS water may interact with adversely is the RS-25 engine nozzles and the SRB nozzles. The adverse interaction anticipated is the wetting, to a significant degree, of the RS-25 nozzles resulting in substantial weight of ice forming and water present to a significant degree upstream of the SRB nozzle exit plane inside the nozzle itself, posing significant additional blockage of the effluent that exits the nozzle

  18. Analysis of a weld of an hydrogen tank under pressure: contribution of the nano-indentation for the characterization

    International Nuclear Information System (INIS)

    This work deals with the size of an hydrogen spherical tank under pressure, composed of two half shell in aluminium alloy AZ5G machined in a forged bar and welded by electrons beam by a circumference. In this work, it is shown what the nano-indentation test can bring here. The influence of the tempering heat treatment after welding, the grains diameter and the loss in alloy elements (Zn and Mg) on the local mechanical properties of the weld bead has been revealed. In the same way, a hardening of the alloy due to the hydrogen penetration and leading to an increase of the dislocations density is observed. (O.M.)

  19. Preliminary study for the microstructural characterization of Zr-2.5Nb pressure pipes by electron microscopy

    International Nuclear Information System (INIS)

    The Embalse Nuclear Power Station (CNE) is a CANadian Deuterium Uranium (CANDU) Reactor. One of the acceptance criteria for the Zr-2,5Nb alloy pressure tubes of the CNE is based on the width of the α-Zr phase. This width is manually measured, using image processing software. The first part of this paper is oriented to weigh the human factor of these measures and find a proper image treatment to minimize this error. In the second part an automatic procedure is proposed, in order to measure the width of the α-Zr phase and become independent on the human factor (author)

  20. High-Pressure Synthesis and Characterization of New Actinide Borates, AnB4O8 (An=Th, U)

    OpenAIRE

    Hinteregger, Ernst; Hofer, Thomas S.; Heymann, Gunter; Perfler, Lukas; Kraus, Florian; Huppertz, Hubert

    2013-01-01

    New actinide borates ThB4O8 and UB4O8 were synthesized under high-pressure, high-temperature conditions (5.5 GPa/1100 °C for thorium borate, 10.5 GPa/1100 °C for the isotypic uranium borate) in a Walker-type multianvil apparatus from their corresponding actinide oxide and boron oxide. The crystal structure was determined on basis of single-crystal X-ray diffraction data that were collected at room temperature. Both compounds crystallized in the monoclinic space group C2/c (Z=4). Lattice param...

  1. Preparation and characterization of ZrO2:Er3+, Yb3+ nanoparticles using a high pressure assisted soft template

    International Nuclear Information System (INIS)

    Nanoparticles of ZrO2:Er3+, Yb3+ fabricated by a soft template method combined with microwave heating under high pressures were reported for the first time. Nano ZrO2:Er3+, Yb3+ in concentrations of 0.1–15 mol% have been fabricated in the presence of soft template agent diethylene glycol or polyethylene glycol in a microwave reactor at pressures up to 55 atm. The average size of the as-synthesized nanoparticles was found to be 5–13 nm. The upconversion luminescence of the ZrO2:Er3+, Yb3+ was found in the red region of 630–710 nm and in the green region of 510–570 nm, with excitation by an infrared diode laser at the wavelengths of 830 and 940 nm, respectively. The change in content ratio between monoclinic and tetragonal phases when the annealing temperature increases from 600 to 1200 °C was investigated. The tetragonal phase content decreases and disappears for the samples annealed at 1200 °C. The increase in the content of the monoclinic phase is suggested to be a main reason for the increase in the upconversion luminescent intensity of nano ZrO2:Er3+, Yb3+

  2. High-pressure synthesis and characterization of the first cerium fluoride borate CeB2O4F

    International Nuclear Information System (INIS)

    CeB2O4F is the first cerium fluoride borate, which is exclusively built up of one-dimensional, infinite chains of condensed trigonal-planar [BO3]3− groups. This new cerium fluoride borate was synthesized under high-pressure/high-temperature conditions of 0.9 GPa and 1450 °C in a Walker-type multianvil apparatus. The compound crystallizes in the orthorhombic space group Pbca (No. 61) with eight formula units and the lattice parameters a=821.63(5), b=1257.50(9), c=726.71(6) pm, V=750.84(9) Å3, R1=0.0698, and wR2=0.0682 (all data). The structure exhibits a 9+1 coordinated cerium ion, one three-fold coordinated fluoride ion and a one-dimensional chain of [BO3]3− groups. Furthermore, IR spectroscopy, Electron Micro Probe Analysis and temperature-dependent X-ray powder diffraction measurements were performed. - Graphical abstract: A new rare-earth fluoride borate CeB2O4F could be synthesized under high-pressure/high-temperature conditions of 0.9 °GPa and 1450 °Cin a Walker-type multianvil apparatus. The crystal structure represents a new structure type in the class of rare-earth fluoride borates. The structure exhibits a 9+1 coordinated cerium ion, one three-fold coordinated fluoride ion and a one-dimensional chain of [BO3]3− groups. A closer view on the ac-plane shows an interesting wave-like modulation of the borate chains. Highlights: • CeB2O4F is the first fluoride borate exclusively built up of one-dimensional, infinite chains of condensed trigonal-planar [BO3]3− groups. • CeB2O4F is the first cerium fluoride borate. • High-pressure conditions were necessary to synthesize CeB2O4F

  3. Low-pressure solvent extraction of oil from macauba (Acrocomia aculeata pulp: characterization of oil and defatted meal

    Directory of Open Access Journals (Sweden)

    Caroline Portilho Trentini

    2015-01-01

    Full Text Available ABSTRACT: This study aimed to extract the oil from macauba pulp using a low-pressure solvent extraction, as well as characterisation of the extracts and defatted meal obtained using different solvents (n-hexane, ethyl acetate and isopropanol. Results reported higher yields in oil, 27.43%, using isopropanol (P0.05 on the composition; however, in the quantification of free glycerol compounds, isopropanol showed higher levels, 104.15mg 100g-1, of these compounds (P<0.05. Meals had higher ash, protein and fibre content when compared to pulp. Thus, oil removal can be stated to promote water retention capacity; however, it has no influence on the other technological characteristics evaluated.

  4. Characterization of Ba2YCu3Ox as a function of oxygen partial pressure Part I: Thermoanalytical measurements

    International Nuclear Information System (INIS)

    The equilibrium oxygen content, X, in the range 6 2YCu3Ox as a function of PO2 and temperature over the ranges 10-3 O2 O2 versus reciprocal temperature. Enthalpy for the oxidation as derived from the slopes of these lines is found to vary from 24 to 26.5 kcal mol-1 (per oxygen atom). These data are derived from thermogravimetry in flowing 100, 21, 2, 1, and 0.091% O2 at atmospheric pressure. Other supporting thermoanalytical data, DSC, DTA, and EGA are presented to further help understand the effects of atmosphere in this system. For example, the melting point of Ba2YCu3Ox as determined from DTA at 20 degree C min-1 was found to vary from approximately 975 degree C in N2 to about 1035 degree C in O2

  5. Design and characterization of an RF excited micro atmospheric pressure plasma jet for reference in plasma medicine

    Science.gov (United States)

    Schulz-von der Gathen, Volker

    2015-09-01

    Over the last decade a huge variety of atmospheric pressure plasma jets has been developed and applied for plasma medicine. The efficiency of these non-equilibrium plasmas for biological application is based on the generated amounts of reactive species and radiation. The gas temperatures stay within a range tolerable for temperature-sensitive tissues. The variety of different discharge geometries complicates a direct comparison. In addition, in plasma-medicine the combination of plasma with reactive components, ambient air, as well as biologic tissue - typically also incorporating fluids - results in a complex system. Thus, real progress in plasma-medicine requires a profound knowledge of species, their fluxes and processes hitting biological tissues. That will allow in particular the necessary tailoring of the discharge to fit the conditions. The complexity of the problem can only be overcome by a common effort of many groups and requires a comparison of their results. A reference device based on the already well-investigated micro-scaled atmospheric pressure plasma jet is presented. It is developed in the frame of the European COST initiative MP1101 to establish a publicly available, stable and reproducible source, where required plasma conditions can be investigated. Here we present the design and the ideas behind. The presentation discusses the requirements for the reference source and operation conditions. Biological references are also defined by the initiative. A specific part of the talk will be attributed to the reproducibility of results from various samples of the device. Funding by the DFG within the Package Project PAK816 ``Plasma Cell Interaction in Dermatology'' and the Research Unit FOR 1123 ``Physics of microplasmas'' is gratefully acknowledged.

  6. Characterization of long-lived activation products in spent fuel assembly hardware and reactor pressure vessel steel

    International Nuclear Information System (INIS)

    Extensive measurements have provided the basis for evaluating the radionuclide concentrations, distributions, inventories, waste classification, and disposal options for activated metal wastes generated during reactor decommissioning. A variety of neutron-activated metal specimens associated with spent fuel assembly hardware from commercial nuclear power stations and pressure vessel steel from the decommissioned Gundremmingen KRB-A reactor were subjected to detailed radionuclide and stable element analyses. Emphasis was placed on the long-lived radionuclides specified in 10CFR61, including Mn-54, Fe-55, Co-60, Ni-59, Ni-63 and Nb-94. In addition, it was discovered that much higher concentrations of Nb-93m were present in activated Inconel and stainless steel than earlier calculations had predicted. The concentrations of Ni-63, Ni-59, and Nb-94 in Inconel components, and Ni-63 and Ni-59 in stainless steel components were often much greater than the Class C limit, indicating that these materials would have to be disposed of as high level waste. The accuracy of calculational methods for predicting radionuclide concentrations in activated metal wastes was evaluated by conducting blind comparisons of empirical versus predicted values. This comparison showed that good agreements were achieved for the fueled regions of the fuel assemblies, but at the tops and bottoms of the assemblies the calculated values were, in some cases, significantly in error. The agreement between measured versus predicted radionuclide concentrations for the Gundremmingen pressure vessel steel was good. These evaluations have provided confidence in the calculational methods and have identified problem areas where improvements are warranted. (orig.)

  7. The differentiation between the turbulence and two-phase models to characterize a Diesel spray at high injection pressure

    Directory of Open Access Journals (Sweden)

    L. Souinida

    2015-01-01

    Full Text Available The aim of this work is a study of the dynamics of the diesel spray in a combustion chamber of a Diesel engine of direct injection during the injection spray. To do it, the computer code Fluent (simulator of turbulent multiphase, multi-dimensional and unsteadies flows is used to model the behavior of the spray in two dimensions. The spray evolution is simulated by using the Reynolds Averaged Navier-Stokes equations with a many models of closure of these equations, such as: Spalart Allmaras, k-ε, k-ω, k-kL-ω, SAS, RSM. The twophase flow is modeled by using the Volume of Fluid model and its coupling with Level-Set model, where the two phases behave as a pseudo-fluid with an indicator function determining the volume fraction of each phase. In this study, we demonstrate the evolution of the volume fraction field of the liquid and the averaged velocity field of the mixture, characterizing the behavior of the dynamic spray. Also, we drew the temporal evolution of the penetration length of our calculation (for all turbulence models cited above with the experiment curve and that of computer code AVBP. Finally, we deduced the appropriate model of turbulence and two-phase flow for better characterizing the dynamic of the diesel spray.

  8. A study on characterization of atmospheric pressure plasma jets according to the driving frequency for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Y.S.; Lee, H.Wk.; Kwon, H.C.; Choi, J.; Lee, S.M. [Electronics and Electrical Engineering Department, Pohang University of Science and Technology, Pohang, Gyungbuk, 790-784 (Korea, Republic of); Woo, K.C.; Kim, K.T. [Department of Life Science, Pohang University of Science and Technology, Pohang, Gyungbuk, 790-784 (Korea, Republic of); Lee, J.K., E-mail: jkl@postech.ac.kr [Electronics and Electrical Engineering Department, Pohang University of Science and Technology, Pohang, Gyungbuk, 790-784 (Korea, Republic of)

    2011-08-01

    Unique atmospheric pressure plasma devices are designed to investigate the plasma characteristics for various driving frequencies under the same operating conditions. Electrical properties of the plasma, gas temperature, formation of plasma jets, and sterilization efficiency are studied for two different driving frequencies of 13 kHz (low frequency) and 877 MHz (microwave frequency). When compared with low frequency plasma, microwave plasma is found to have better electrical properties such as no electric shock for safety, high discharge current for effective chemical reactions, clean waveform for homogenous plasma, and high power coupling efficiency. Furthermore, microwave plasma leads to effective sterilization which is related to the high intensity of atomic oxygen. One-dimensional particle-in-cell simulation reveals that microwave plasma has substantial electrons in the energy range 2-5 eV (bond dissociation energy), thus electrons in this energy range can produce more atomic oxygen. It shows that the probability of producing high energy ions, which can damage the electrode, is low in microwave plasma.

  9. A study on characterization of atmospheric pressure plasma jets according to the driving frequency for biomedical applications

    International Nuclear Information System (INIS)

    Unique atmospheric pressure plasma devices are designed to investigate the plasma characteristics for various driving frequencies under the same operating conditions. Electrical properties of the plasma, gas temperature, formation of plasma jets, and sterilization efficiency are studied for two different driving frequencies of 13 kHz (low frequency) and 877 MHz (microwave frequency). When compared with low frequency plasma, microwave plasma is found to have better electrical properties such as no electric shock for safety, high discharge current for effective chemical reactions, clean waveform for homogenous plasma, and high power coupling efficiency. Furthermore, microwave plasma leads to effective sterilization which is related to the high intensity of atomic oxygen. One-dimensional particle-in-cell simulation reveals that microwave plasma has substantial electrons in the energy range 2-5 eV (bond dissociation energy), thus electrons in this energy range can produce more atomic oxygen. It shows that the probability of producing high energy ions, which can damage the electrode, is low in microwave plasma.

  10. Atmospheric pressure argon surface discharges propagated in long tubes: physical characterization and application to bio-decontamination

    Science.gov (United States)

    Kovalova, Zuzana; Leroy, Magali; Jacobs, Carolyn; Kirkpatrick, Michael J.; Machala, Zdenko; Lopes, Filipa; Laux, Christophe O.; DuBow, Michael S.; Odic, Emmanuel

    2015-11-01

    Pulsed corona discharges propagated in argon (or in argon with added water vapor) at atmospheric pressure on the interior surface of a 49 cm long quartz tube were investigated for the application of surface bio-decontamination. H2O molecule dissociation in the argon plasma generated reactive species (i.e. OH in ground and excited states) and UV emission, which both directly affected bacterial cells. In order to facilitate the evaluation of the contribution of UV radiation, a DNA damage repair defective bacterial strain, Escherichia coli DH-1, was used. Discharge characteristics, including propagation velocity and plasma temperature, were measured. Up to ~5.5 and ~5 log10 reductions were observed for E. coli DH-1 bacteria (from 106 initial load) exposed 2 cm and 44 cm away from the charged electrode, respectively, for a 20 min plasma treatment. The factors contributing to the observed bactericidal effect include desiccation, reactive oxygen species (OH) plus H2O2 accumulation in the liquid phase, and UV-B (and possibly VUV) emission in dry argon. The steady state temperature measured on the quartz tube wall did not exceeded 29 °C the contribution of heating, along with that of H2O2 accumulation, was estimated to be low. The effect of UV-B emission alone or in combination with the other stress factors of the plasma process was examined for different operating conditions.

  11. Characterization of Ba2YCu3Ox as a function of oxygen partial pressure. Part II. Dependence of the O-T transition on oxygen content

    International Nuclear Information System (INIS)

    Dilatometry and high temperature x-ray powder diffraction have been used to characterize the orthorhombic (O) to tetragonal (T) transition in the 93K superconductor Ba2YCu3Ox (7.0 > X > 6.0). The O-T transition temperature has been determined as function of oxygen partial pressure, PO2 = 0.09, 2%, air and 100% oxygen. Thermal expansion coefficients for individual lattice parameters as well as average values have been measured for the O and T structures. A volume change of ∼ +0.21% has been observed for transformation of O to T at 650 degree C. The structural change occurs at X = 6.63 ± 0.3

  12. Normal blood pressure and preserved diurnal variation in offspring of type 2 diabetic patients characterized by features of the metabolic syndrome: the Fredericia Study

    DEFF Research Database (Denmark)

    Foss, Catherine Hauerslev; Vestbo, Else; Frøland, Anders; Gjessing, Hans; Mogensen, Carl Erik; Damsgaard, Else Marie Skjøde

    . CONCLUSIONS: This study shows a preserved diurnal BP profile and a normal BP level in the nondiabetic glucose-tolerant offspring of type 2 diabetic subjects compared with the offspring of nondiabetic subjects, although the offspring of diabetic patients are characterized by features of the metabolic syndrome.......OBJECTIVE: To examine whether an elevated blood pressure (BP) level and an impaired reduction in nocturnal BP are already present in nondiabetic first-degree relatives of type 2 diabetic patients. RESEARCH DESIGN AND METHODS: We examined 253 offspring of type 2 diabetic patients using ambulatory BP...... between the nondiabetic glucose-tolerant offspring of type 2 diabetic subjects and the offspring of nondiabetic subjects. BMI (P < 0.05 and P < 0.01, male vs. female), waist-to-hip ratio (P < 0.05), fasting blood glucose (P < 0.01), C-peptide (P < 0.05 and P < 0.01, male vs. female), insulin resistance...

  13. Characterization of Damage to Bacteria and Bio-macromolecules Caused by (V)UV Radiation and Particles Generated by a Microscale Atmospheric Pressure Plasma Jet

    Science.gov (United States)

    Lackmann, Jan-Wilm; Schneider, Simon; Narberhaus, Franz; Benedikt, Jan; Bandow, Julia E.

    Atmospheric pressure plasma jets effectively inactivate bacteria on ­surfaces including infected tissues. This is due to the combined effects of (V)UV radiation, reactive oxygen and nitrogen species, ions, and high electric fields. A well-characterized microscale atmospheric pressure plasma jet (μ-APPJ) operated with He/O2 gas mixture has been modified so that (V)UV radiation and heavy reactive particles (mainly O3 molecules and O atoms) emitted from the plasma source can be separated effectively. The separation is achieved by an additional lateral He flow, which diverts the heavy particles from the jet axis. The new jet geometry is called X-Jet. Separation of different plasma components allows studying their effects on living cells and bio-macromolecules separately. First, the effectiveness of the separation of different plasma components was demonstrated by treatment of monolayers of vegetative Bacillus subtilis cells. To characterize effects on nucleic acids, dried plasmid DNA and total cellular RNA were treated with the separated plasma components. Dried bovine serum albumin was used to study etching effects of (V)UV radiation and heavy particles on proteins. We found that heavy particles emitted from the X-Jet kill vegetative cells more effectively than the (V)UV radiation from this type of plasma source. All bio-macromolecules investigated, DNA, RNA, and proteins, are affected by plasma treatment. DNA exposed to the (V)UV-channel of the jet seems to be prone to thymine dimer formation not only in vitro but also in vivo as indicated by induction of the photolyase in Escherichia coli, while DNA strand breaks occur under both jet channels. Heavy particles seem more effective in degrading RNA and in etching protein in vitro.

  14. Microstructural characterization and model of hardening for the irradiated austenitic stainless steels of the internals of pressurized water reactors

    International Nuclear Information System (INIS)

    The core internals of Pressurized Water Reactors (PWR) are composed of SA 304 stainless steel plates and CW 316 stainless steel bolts. These internals undergo a neutron flux at a temperature between 280 deg C and 380 deg C which modifies their mechanical properties. These modifications are due to the changes in the microstructure of these materials under irradiation which depend on flux, dose and irradiation temperature. We have studied, by Transmission Electron Microscopy, the microstructure of stainless steels SA 304, CW 316 and CW 316Ti irradiated in a mixed flux reactor (OSIRIS at 330 deg C between 0,8 dpa et 3,4 dpa) and in a fast breeder reactor at 330 deg C (BOR-60) up to doses of 40 dpa. Moreover, samples have been irradiated at 375 deg C in a fast breeder reactor (EBR-II) up to doses of 10 dpa. The microstructure of the irradiated stainless steels consists in faulted Frank dislocation loops in the [111] planes of austenitic, with a Burgers vector of [111]. It is possible to find some voids in the solution annealed samples irradiated at 375 deg C. The evolution of the dislocations loops and voids has been simulated with a 'cluster dynamic' model. The fit of the model parameters has allowed us to have a quantitative description of our experimental results. This description of the microstructure after irradiation was coupled together with a hardening model by Frank loops that has permitted us to make a quantitative description of the hardening of SA 304, CW 316 and CW 316Ti stainless steels after irradiation at a certain dose, flux and temperature. The irradiation doses studied grow up to 90 dpa, dose of the end of life of PWR internals. (author)

  15. Banks of microscopic forms and survival to darkness of propagules and microscopic stages of macroalgae Bancos de formas microscópicas y supervivencia a la oscuridad de propágulos y formas microscópicas de macroalgas

    Directory of Open Access Journals (Sweden)

    BERNABÉ SANTELICES

    2002-09-01

    Full Text Available Previous studies have found that the number of species conforming a bank of microscopic forms in tide pools in central Chile accounted only for half the number of species present in the macroscopic vegetation around the pools. An elemental condition for survival in these banks is the ability of microscopic forms to tolerate darkness or very low irradiances for extended periods. To test this ability, spores of 17 green, brown and red algal species, present and absent from the bank, were incubated at different combinations of irradiances and day lengths. Propagules of 47 % of the species tested (eight species germinated in total darkness while the propagules of the other nine species germinated under conditions of very low irradiance (2-10 µmol m-2 s-1. In most species, microforms showed a higher tolerance to darkness than the propagules. Some survived for over a year and one species (Gelidium lingulatum could live under complete darkness for 500 days. The ability to survive in total darkness did not relate to presence or absence of a species in the banks of microscopic forms previously studied, to phylogenetic relatedness, life history style, propagule size, morphology of microscopic forms or to successional status (fugitive versus late successional. Thus, tolerance to darkness appears to be common to propagules and microscopic stages of most benthic algae. The growth patterns exhibited by the microforms of Lessonia nigrescens, Chaetomorpha firma and Glossophora kunthii suggest high irradiances on these recruits might determine the shallower limits of distribution of these speciesEstudios previos han encontrado que el número de especies formando un banco de formas microscópicas en pozas de mareas de Chile central incluyó sólo la mitad del número de especies presentes en la vegetación macroscópica en las cercanías de las pozas intermareales. Una primera condición para sobrevivir en estos bancos radica en la capacidad de las formas

  16. Blood pressure

    Science.gov (United States)

    ... the walls of the arteries is called blood pressure. Blood pressure is measured both as the heart contracts, which ... as it relaxes, which is called diastole. Normal blood pressure is considered to be a systolic blood pressure ...

  17. High-Pressure Microfluidics

    OpenAIRE

    Ogden, Sam

    2013-01-01

    In this thesis, some fundamentals and possible applications of high-pressure microfluidics have been explored. Furthermore, handling fluids at high pressures has been addressed, specifically by creating and characterizing strong microvalves and pumps. A variety of microstructuring techniques was used to realize these microfluidic devices, e.g., etching, lithography, and bonding. To be able to handle high pressures, the valves and pumps need to be strong. This necessitates a strong actuator ma...

  18. Topological characterization of the transition from laminar regime to fully developed turbulence in the resistive pressure-gradient-driven turbulence model

    International Nuclear Information System (INIS)

    For the resistive pressure-gradient-driven turbulence model, the transition from laminar regime to fully developed turbulence is not simple and goes through several phases. For low values of the plasma parameter β, a single quasicoherent structure forms. As β increases, several of these structures may emerge and in turn take the dominant role. Finally, at high β, fully developed turbulence with a broad spectrum is established. A suitable characterization of this transition can be given in terms of topological properties of the flow. Here, we analyze these properties that provide an understanding of the turbulence-induced transport and give a measure of the breaking of the homogeneity of the turbulence. To this end, an approach is developed that allows discriminating between topological properties of plasma turbulence flows that are relevant to the transport dynamics and the ones that are not. This is done using computational homology tools and leads to a faster convergence of numerical results for a fixed level of resolution than previously presented in Phys. Rev. E 78, 066402 (2008).

  19. Topological characterization of the transition from laminar regime to fully developed turbulence in the resistive pressure-gradient-driven turbulence model

    Science.gov (United States)

    Garcia, L.; Carreras, B. A.; Llerena, I.; Calvo, I.

    2009-10-01

    For the resistive pressure-gradient-driven turbulence model, the transition from laminar regime to fully developed turbulence is not simple and goes through several phases. For low values of the plasma parameter β , a single quasicoherent structure forms. As β increases, several of these structures may emerge and in turn take the dominant role. Finally, at high β , fully developed turbulence with a broad spectrum is established. A suitable characterization of this transition can be given in terms of topological properties of the flow. Here, we analyze these properties that provide an understanding of the turbulence-induced transport and give a measure of the breaking of the homogeneity of the turbulence. To this end, an approach is developed that allows discriminating between topological properties of plasma turbulence flows that are relevant to the transport dynamics and the ones that are not. This is done using computational homology tools and leads to a faster convergence of numerical results for a fixed level of resolution than previously presented in Phys. Rev. E 78, 066402 (2008).

  20. Characterization of C-strain “Riems” TAV-epitope escape variants obtained through selective antibody pressure in cell culture

    Directory of Open Access Journals (Sweden)

    Leifer Immanuel

    2012-04-01

    Full Text Available Abstract Classical swine fever virus (CSFV C-strain “Riems” escape variants generated under selective antibody pressure with monoclonal antibodies and a peptide-specific antiserum in cell culture were investigated. Candidates with up to three amino acid exchanges in the immunodominant and highly conserved linear TAV-epitope of the E2-glycoprotein, and additional mutations in the envelope proteins ERNS and E1, were characterized both in vitro and in vivo. It was further demonstrated, that intramuscular immunization of weaner pigs with variants selected after a series of passages elicited full protection against lethal CSFV challenge infection. These novel CSFV C-strain variants with exchanges in the TAV-epitope present potential marker vaccine candidates. The DIVA (differentiating infected from vaccinated animals principle was tested for those variants using commercially available E2 antibody detection ELISA. Moreover, direct virus differentiation is possible using a real-time RT-PCR system specific for the new C-strain virus escape variants or using differential immunofluorescence staining.

  1. Characterizing the effects of elevated temperature on the air void pore structure of advanced gas-cooled reactor pressure vessel concrete using x-ray computed tomography

    International Nuclear Information System (INIS)

    X-ray computed tomography (X-ray CT) has been applied to nondestructively characterise changes in the microstructure of a concrete used in the pressure vessel structure of Advanced Gas-cooled Reactors (AGR) in the UK. Concrete specimens were conditioned at temperatures of 105 C and 250 C, to simulate the maximum thermal load expected to occur during a loss of coolant accident (LOCA). Following thermal treatment, these specimens along with an unconditioned control sample were characterised using micro-focus X-ray CT with a spatial resolution of 14.6 microns. The results indicate that the air void pore structure of the specimens experienced significant volume changes as a result of the increasing temperature. The increase in the porous volume was more prevalent at 250 C. Alterations in air void size distributions were characterized with respect to the unconditioned control specimen. These findings appear to correlate with changes in the uni-axial compressive strength of the conditioned concrete. (authors)

  2. Characterization of the CCR3 and CCR9 genes in miiuy croaker and different selection pressures imposed on different domains between mammals and teleosts.

    Science.gov (United States)

    Zhu, Zhihuang; Wang, Rixin; Ren, Liping; Xu, Tianjun

    2013-12-01

    The innate immune system can recognize non-self through pattern recognition receptors and provides a first line of antimicrobial host defense. Thus innate immunity plays a very important role in resistance against major bacterial disease in vertebrates. In the innate immune responses, the chemokine receptors act as the main receptors of chemokines which are released at the sites of infection, inflammation and injury. In this study, the Miichthys miiuy CCR3 and CCR9 genes were cloned and characterized, showing that MIMI-CCR3 possesses a highly conserved DRYLA motif similar to that of other fishes. MIMI-CCR3 and CCR9 were ubiquitously expressed in all tested tissues and the expressions were significantly up-regulated after infection with Vibrio anguillarum except that of CCR9 in spleen. Evolutionary analysis showed that all the ancestral lineages of CCR3 and CCR9 in mammals and teleosts underwent positive selection, indicating that the ancestor of terrestrial animals further evolved to adapt to terrestrial environments and the continuous intrusion of microbes stimulated the evolution of CCR genes in the ancestor of teleost. Multiple ML methods were used to detect the robust candidates for sites under positive selection. In total, 11 and 8 positively selected sites were found in the subsets of current mammal and teleost CCR3 genes, and 3 and 2 sites were detected in the subsets of current mammals and teleosts in CCR9. Interestingly, for mammal CCR3 and CCR9 genes, the robust candidates of positively selected sites were mainly located in the extracellular domains which were the ligand binding and pathogen interaction regions. For teleost CCR3 and CCR9 genes, the positively selected sites were not only located in the extracellular domains but also in the C-terminal and intracellular domains, indicating mammals and teleosts experienced different selection pressures upon their N-terminus, C-terminus and intracellular loops of CCRs. PMID:23817141

  3. Microstructural characterization and process selection by attributive analysis of eutectic and quasi-eutectic Al-Si alloys for pressure die casting

    Directory of Open Access Journals (Sweden)

    Suárez-Peña, B.

    2007-08-01

    Full Text Available In the present study, four alloys from diverse suppliers suitable for obtaining 413.0 metallurgical quality products together with alloy number 2 with an slightly hypoeutectic composition in Silicon were processed. The study focused on the microstructural characterization of the as-received ingots, as well as that of samples obtained from the production process: die cast samples and cold chamber pressure die cast samples. Finally a materials selection process base on microstructural grounds has been put forward as to determine the most suitable starting alloy for industrial production.

    En el presente trabajo se han analizado cinco aleaciones procedentes de diferentes proveedores aptas para la obtención de componentes de la calidad metalúrgica 413.0, con excepción de la aleación 2 de composición levemente hipoeutéctica. El estudio se centra en la caracterización microestructural de los lingotes en estado de recepción, así como de las muestras obtenidas a partir del proceso de fabricación: muestras coladas en molde metálico y muestras fabricadas mediante fundición a presión en cámara fría. Finalmente se propone un proceso de selección de material basado en consideraciones microestructurales que permite determinar la aleación de partida más apta para la producción industrial mediante fundición a presión.

  4. Characterizing workers participating in a worksite wellness health screening program using blood pressure control, self-monitoring, medication adherence, depression, and exercise.

    Science.gov (United States)

    Breaux-Shropshire, Tonya Lynn; Whitt, Lauren; Griffin, Russell L; Shropshire, Angele Trenese; Calhoun, David A

    2014-07-01

    Blood pressure control remains a serious public health issue because hypertension is the most common risk factor for cardiovascular disease. Effective management of hypertension often requires lifestyle modification and medication adherence. The objective of this study was to identify the prevalence of blood pressure control, medication adherence, self-monitoring of blood pressure, depression, and exercise among workers with access to health resources. Faculty and staff (N = 484) from a university and health care institution in the southeastern United States participated in biometric and questionnaire screening. The researchers used initial screening data from this worksite wellness program to describe baseline blood pressure control (< 140/90 mm Hg), self-monitoring of blood pressure, medication adherence, depression, and exercise. Overall, 63% of the workers' blood pressure was controlled; however, 23% of the sample had been prescribed antihypertensive medication to control their blood pressure. Thirty percent of the sample reported practicing blood pressure self-monitoring, 72.2% reported that they exercised, and 22% reported feeling down and depressed. More than half (64.9%) who used prescribed antihypertensive medication reported adherence to these medications. PMID:25000548

  5. High-pressure synthesis and characterization of the effective pseudospin S =1 /2 XY pyrochlores R2P t2O7 (R =Er ,Yb )

    Science.gov (United States)

    Cai, Y. Q.; Cui, Q.; Li, X.; Dun, Z. L.; Ma, J.; dela Cruz, C.; Jiao, Y. Y.; Liao, J.; Sun, P. J.; Li, Y. Q.; Zhou, J. S.; Goodenough, J. B.; Zhou, H. D.; Cheng, J.-G.

    2016-01-01

    We report on the high-pressure syntheses and detailed characterizations of two effective pseudospin S =1 /2 XY pyrochlores E r2P t2O7 and Y b2P t2O7 via x-ray/neutron powder diffraction, dc and ac magnetic susceptibility, and specific-heat measurements down to 70 mK. We found that both compounds undergo long-range magnetic transitions at TN ,C≈0.3 K , which are ascribed to an antiferromagnetic- and ferromagnetic-type order for E r2P t2O7 and Y b2P t2O7 , respectively, based on the field dependence of their transition temperatures as well as the systematic comparisons with other similar pyrochlores R2B2O7 (R =Er ,Yb ;B =Sn ,Ti ,Ge ). The observed TN of E r2P t2O7 is much lower than that expected from the relationship of TN versus the ionic radius of B4 + derived from the series of E r2B2O7 , while the TC of Y b2P t2O7 is the highest among the series of ferromagnetic compounds Y b2B2O7 (B =Sn ,Pt ,Ti ). Given the monotonic variation of the lattice constant as a function of the B -cation size across these two series of R2B2O7 (R =Er ,Yb ), the observed anomalous values of TN ,C in the Pt-based XY pyrochlores imply that another important factor beyond the nearest-neighbor R -R distance is playing a role. In light of the anisotropic exchange interactions Jex={Jz z,J±,J±±,Jz ± } for the S =1 /2 XY pyrochlores, we have rationalized these observations by considering a weakened (enhanced) antiferromagnetic planar J± (ferromagnetic Ising-like Jz z) due to strong Pt 5 d -O 2 p hybridization within the plane perpendicular to the local [111] direction.

  6. A comparative study on the analytical utility of atmospheric and low-pressure MALDI sources for the mass spectrometric characterization of peptides.

    Science.gov (United States)

    Moskovets, Eugene; Misharin, Alexander; Laiko, Viktor; Doroshenko, Vladimir

    2016-07-15

    A comparative MS study was conducted on the analytical performance of two matrix-assisted laser desorption/ionization (MALDI) sources that operated at either low pressure (∼1Torr) or at atmospheric pressure. In both cases, the MALDI sources were attached to a linear ion trap mass spectrometer equipped with a two-stage ion funnel. The obtained results indicate that the limits of detection, in the analysis of identical peptide samples, were much lower with the source that was operated slightly below the 1-Torr pressure. In the low-pressure (LP) MALDI source, ion signals were observed at a laser fluence that was considerably lower than the one determining the appearance of ion signals in the atmospheric pressure (AP) MALDI source. When the near-threshold laser fluences were used to record MALDI MS spectra at 1-Torr and 750-Torr pressures, the level of chemical noise at the 1-Torr pressure was much lower compared to that at AP. The dependency of the analyte ion signals on the accelerating field which dragged the ions from the MALDI plate to the MS analyzer are presented for the LP and AP MALDI sources. The study indicates that the laser fluence, background gas pressure, and field accelerating the ions away from a MALDI plate were the main parameters which determined the ion yield, signal-to-noise (S/N) ratios, the fragmentation of the analyte ions, and adduct formation in the LP and AP MALDI MS methods. The presented results can be helpful for a deeper insight into the mechanisms responsible for the ion formation in MALDI. PMID:26899429

  7. Pressure Sores

    Science.gov (United States)

    ... pressure sore include the following: Thick yellow or green pus A bad smell from the sore Redness ... spots, color changes or other signs of sores. Pay special attention to the pressure points where sores ...

  8. Pressure ulcers.

    Science.gov (United States)

    O'Byrne, Deborah

    2016-04-13

    My nursing experience is in acute care. Acute medical nurses are well placed to assess skin integrity, identify patients at risk of pressure ulcer development, and commence appropriate interventions to prevent or treat pressure ulcers. PMID:27073966

  9. Peer Pressure

    Science.gov (United States)

    ... How Can I Help a Friend Who Cuts? Peer Pressure KidsHealth > For Teens > Peer Pressure Print A A A Text Size What's in ... She'd just had a big dose of peer pressure. Who Are Your Peers? When you were a ...

  10. Propagules removal in fragments of native forest and in reforested areas in an Araucaria Forest region of Paraná State Remoção de propágulos em fragmento de floresta nativa e reflorestamentos numa região de Floresta Ombrófila Mista do estado do Paraná

    Directory of Open Access Journals (Sweden)

    Yves Rafael Bovolenta

    2011-06-01

    Full Text Available A question that has been discussed is the role that reforestations with exotic species in native fauna and several studies have shown that removal of propagules is lower in these environments. This study compared the removal rate of propagules (araucaria seeds, peanuts, corn from areas of native forest (FN, reforestations of Pinus taeda L. (RP, Eucalyptus saligna Sm. (RE and Araucaria angustifolia (Bertol Kuntze (RA. In FN all propagules were removed. There was no difference in the removal of araucaria seeds between FN and RA, and removal rate in both areas differ from the removal rate in the RP and RE. In RP there was high removal of peanuts, while the RE showed the lowest value of removal of the three propagules. The low removal rates in reforestation of pine and eucalyptus reflect the decreased exploitation of these habitats for wildlife, which may be related to a poorly structured understory. Uma questão que tem sido discutida é o papel das monoculturas florestais exóticas na manutenção da fauna nativa e vários estudos têm mostrado que a remoção de propágulos é menor nesses ambientes. O presente trabalho comparou a taxa de remoção de propágulos (pinhão, amendoim, milho entre áreas de Floresta Nativa (FN, Reflorestamentos de Pinus taeda L. (RP, de Eucalyptus saligna Sm. (RE e Araucaria angustifolia (Bertol Kuntze (RA. Na FN, todos os propágulos foram removidos e não houve diferença significativa na remoção de pinhão entre a FN e o RA. A remoção de propágulos nessas áreas diferiu da remoção no RP e RE. No RP, houve alta remoção de amendoim, enquanto que o RE apresentou os menores valores de remoção dos três propágulos. As baixas taxas de remoção nos reflorestamentos de pinus e eucalipto refletem a menor exploração desses habitas pela fauna, o que pode estar relacionado com um subosque pouco estruturado.

  11. Characterization of the startup transient electrokinetic flow in rectangular channels of arbitrary dimensions, zeta potential distribution, and time-varying pressure gradient.

    Science.gov (United States)

    Miller, Andrew; Villegas, Arturo; Diez, F Javier

    2015-03-01

    The solution to the startup transient EOF in an arbitrary rectangular microchannel is derived analytically and validated experimentally. This full 2D transient solution describes the evolution of the flow through five distinct periods until reaching a final steady state. The derived analytical velocity solution is validated experimentally for different channel sizes and aspect ratios under time-varying pressure gradients. The experiments used a time resolved micro particle image velocimetry technique to calculate the startup transient velocity profiles. The measurements captured the effect of time-varying pressure gradient fields derived in the analytical solutions. This is tested by using small reservoirs at both ends of the channel which allowed a time-varying pressure gradient to develop with a time scale on the order of the transient EOF. Results showed that under these common conditions, the effect of the pressure build up in the reservoirs on the temporal development of the transient startup EOF in the channels cannot be neglected. The measurements also captured the analytical predictions for channel walls made of different materials (i.e., zeta potentials). This was tested in channels that had three PDMS and one quartz wall, resulting in a flow with an asymmetric velocity profile due to variations in the zeta potential between the walls. PMID:25502599

  12. Reservoir Characterization and CO2 Plume Migration Modeling Based on Bottom-hole Pressure Data: An Example from the AEP Mountaineer Geological Storage Project

    Science.gov (United States)

    Mishra, Srikanta; Kelley, Mark; Oruganti, YagnaDeepika; Bhattacharya, Indra; Spitznogle, Gary

    2014-05-01

    We present an integrated approach for formation permeability estimation, front tracking, reservoir model calibration, and plume migration modeling based on injection rate and down-hole pressure data from CO2 geologic sequestration projects. The data are taken from the 20 MW CO2 capture and storage project at American Electric Power's Mountaineer Plant in West Virginia, USA. The Mountaineer CO2 injection system consists of two injection wells - one in the Copper Ridge Dolomite formation and one in the Rose Run sandstone formation, and three deep observation wells that were operational between October 2009 and May 2011. Approximately 27000 MT and 10000 MT were injected into the Copper Ridge dolomite formation and Rose Run sandstone formation, respectively. A wealth of pressure and rate data from injection and observation wells is available covering a series of injection and pressure falloff events. The methodology developed and applied for interpreting and integrating the data during reservoir analysis and modeling from the Rose Run formation is the subject of this paper. For the analysis of transient pressure data at the injection and observation wells, the CO2 storage reservoir is conceptualized as a radial composite system, where the inner (invaded) zone consists of both supercritical CO2 and brine, and the outer (uninvaded) zone consists of undisturbed brine. Using established analytical solutions for analyzing fluid injection problems in the petroleum reservoir engineering literature, we show how the late-time pressure derivative response from both injection and observation wells will be identical - reflecting the permeability-thickness product of the undisturbed brine-filled formation. We also show how the expanding CO2 plume affects the "effective" compressibility that can be estimated by history matching injection-falloff data and how this can be used to develop a relationship between the plume radius and "effective" compressibility. This provides a novel non

  13. Pore Characterization of Shale Rock and Shale Interaction with Fluids at Reservoir Pressure-Temperature Conditions Using Small-Angle Neutron Scattering

    Science.gov (United States)

    Ding, M.; Hjelm, R.; Watkins, E.; Xu, H.; Pawar, R.

    2015-12-01

    Oil/gas produced from unconventional reservoirs has become strategically important for the US domestic energy independence. In unconventional realm, hydrocarbons are generated and stored in nanopores media ranging from a few to hundreds of nanometers. Fundamental knowledge of coupled thermo-hydro-mechanical-chemical (THMC) processes that control fluid flow and propagation within nano-pore confinement is critical for maximizing unconventional oil/gas production. The size and confinement of the nanometer pores creates many complex rock-fluid interface interactions. It is imperative to promote innovative experimental studies to decipher physical and chemical processes at the nanopore scale that govern hydrocarbon generation and mass transport of hydrocarbon mixtures in tight shale and other low permeability formations at reservoir pressure-temperature conditions. We have carried out laboratory investigations exploring quantitative relationship between pore characteristics of the Wolfcamp shale from Western Texas and the shale interaction with fluids at reservoir P-T conditions using small-angle neutron scattering (SANS). We have performed SANS measurements of the shale rock in single fluid (e.g., H2O and D2O) and multifluid (CH4/(30% H2O+70% D2O)) systems at various pressures up to 20000 psi and temperature up to 150 oF. Figure 1 shows our SANS data at different pressures with H2O as the pressure medium. Our data analysis using IRENA software suggests that the principal changes of pore volume in the shale occurred on smaller than 50 nm pores and pressure at 5000 psi (Figure 2). Our results also suggest that with increasing P, more water flows into pores; with decreasing P, water is retained in the pores.

  14. On the Cluster Physics of Sunyaev-Zel'dovich and X-Ray Surveys. IV. Characterizing Density and Pressure Clumping due to Infalling Substructures

    Science.gov (United States)

    Battaglia, N.; Bond, J. R.; Pfrommer, C.; Sievers, J. L.

    2015-06-01

    Understanding the outskirts of galaxy clusters at the virial radius (R200) and beyond is critical for an accurate determination of cluster masses, structure growth, and to ensure unbiased cosmological parameter estimates from cluster surveys. This problem has drawn renewed interest due to recent determinations of gas mass fractions beyond R200, which appear to be considerably larger than the cosmic mean. Here, we use a large suite of cosmological hydrodynamical simulations to study the inhomogeneity of the intra-cluster medium and employ different variants of simulated physics, including radiative gas physics and thermal feedback by active galactic nuclei. We find that density and pressure clumping closely trace each other as a function of radius, but the bias on density remains on average \\lt 20% within R200. At larger radii, clumping increases steeply due to the continuous infall of coherent structures that have not yet passed the accretion shock. Density and pressure clumping increase with cluster mass and redshift, which probes on average dynamically younger objects that are still in the process of assembling. The angular power spectra of gas density and pressure show that the clumping signal is dominated by large-scale cosmic filaments that reach from the cosmic web into the clusters, signaling the presence of gravitationally driven “super clumping.” While the prolateness of the gravitational halo potential implies an approximate radial correlation of these gaseous large-scale structures, gas density and pressure lose coherence on small scales across different radii due to dissipative gas physics. In contrast, the angular power spectrum of dark matter shows an almost uniform size distribution due to unimpeded subhalos. We provide a synopsis of the radial dependence of the clusters’ non-equilibrium measures (kinetic pressure support, ellipticity, and clumping) that all increase sharply beyond R200.

  15. On the Cluster Physics of Sunyaev-Zel'dovich and X-ray Surveys IV: Characterizing Density and Pressure Clumping due to Infalling Substructures

    CERN Document Server

    Battaglia, N; Pfrommer, C; Sievers, J L

    2014-01-01

    Understanding the outskirts of galaxy clusters at the virial radius (R200) and beyond is critical for an accurate determination of cluster masses and to ensure unbiased cosmological parameter estimates from cluster surveys. This problem has drawn renewed interest due to recent determinations of gas mass fractions beyond R200, which appear to be considerably larger than the cosmic mean, and because the clusters' total Sunyaev-Zel'dovich flux receives a significant contribution from these regions. Here, we use a large suite of cosmological hydrodynamical simulations to study the clumpiness of density and pressure and employ different variants of simulated physics, including radiative gas physics and thermal feedback by active galactic nuclei. We find that density and pressure clumping closely trace each other as a function of radius, but the bias on density remains on average R200/5, signaling the presence of gravitationally-driven "super-clumping". In contrast, the angular power spectrum of the dark matter (DM...

  16. Characterization of the pressure field induced by the explosions in air of a hydrocarbon-air mixture with slow deflagration of fast deflagration

    International Nuclear Information System (INIS)

    The present research contract, carried out in the framework of a French working group CEA-EDF-ENSMA, was divided into four phases: 1) Phase 1: Scaling effects on a pressure field generated by spontaneous accelerations of deflagrations in a homogeneous medium: these ''CHARLES'' tests performed on completely unconfined charges of ethylene-air and acetylene-air mixture (V approximately= 12 m3) have demonstrated the high sensitivity of the pressure field to the flame acceleration, particularly at the end of the propagation. 2) Phase 2: Effect of a sudden discontinuity in the concentration of the combustible gas on the deflagration speed in a heterogeneous medium: this discontinuity was obtained using two concentric latex balloons, filled with different hydrocarbon concentrations and also destroyed before firing. 3) Phase 3: Study of pseudo-detonation modes for the explosion of spherical ethylene-air mixtures: these modes were sought by increasing an explosive plastic mass associated to the igniter. 4) Phase 4: Study of the influence of cloud shape, ignition point location and simple obstacles in the flame path on the pressure field generated by the explosion. A retractable enclosure was designed, built and unfortunately destroyed by the second test

  17. Characterization of the CO2 fluid adsorption in coal as a function of pressure using neutron scattering techniques (SANS and USANS)

    Science.gov (United States)

    Melnichenko, Y.B.; Radlinski, A.P.; Mastalerz, Maria; Cheng, G.; Rupp, J.

    2009-01-01

    Small angle neutron scattering techniques have been applied to investigate the phase behavior of CO2 injected into coal and possible changes in the coal pore structure that may result from this injection. Three coals were selected for this study: the Seelyville coal from the Illinois Basin (Ro = 0.53%), Baralaba coal from the Bowen Basin (Ro = 0.67%), and Bulli 4 coal from the Sydney Basin (Ro = 1.42%). The coals were selected from different depths to represent the range of the underground CO2 conditions (from subcritical to supercritical) which may be realized in the deep subsurface environment. The experiments were conducted in a high pressure cell and CO2 was injected under a range of pressure conditions, including those corresponding to in-situ hydrostatic subsurface conditions for each coal. Our experiments indicate that the porous matrix of all coals remains essentially unchanged after exposure to CO2 at pressures up to 200??bar (1??bar = 105??Pa). Each coal responds differently to the CO2 exposure and this response appears to be different in pores of various sizes within the same coal. For the Seelyville coal at reservoir conditions (16????C, 50??bar), CO2 condenses from a gas into liquid, which leads to increased average fluid density in the pores (??pore) with sizes (r) 1 ?? 105 ??? r ??? 1 ?? 104???? (??pore ??? 0.489??g/cm3) as well as in small pores with size between 30 and 300???? (??pore ??? 0.671??g/cm3). These values are by a factor of three to four higher than the density of bulk CO2 (??CO2) under similar thermodynamic conditions (??CO2 ??? 0.15??g/cm3). At the same time, in the intermediate size pores with r ??? 1000???? the average fluid density is similar to the density of bulk fluid, which indicates that adsorption does not occur in these pores. At in situ conditions for the Baralaba coal (35 OC, 100??bar), the average fluid density of CO2 in all pores is lower than that of the bulk fluid (??pore / ??CO2 ??? 0.6). Neutron scattering from the

  18. Characterization of structure and properties of TiN-TiB{sub 2} nano-composite prepared by ball milling and high pressure heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, L.X. [Department of Physics, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Department of Material Science and Engineering, Jilin University, Changchun 130012 (China); Yao, B. [Department of Physics, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Key Laboratory of Excited State Process, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Science, Changchun 130022 (China)], E-mail: binyao@jlu.edu.cn; Ding, Z.H. [Department of Physics, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Zheng, Y.J.; Jia, X.P. [Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China); Zheng, W.T. [Department of Material Science and Engineering, Jilin University, Changchun 130012 (China)

    2008-05-29

    Synthesis of TiN-TiB{sub 2} nano-composite was investigated by mechanical milling of mixture of Ti and hexagonal boron nitride (h-BN) and subsequent sintering under high pressure and high temperature (HPHT). A TiN-TiB{sub 2} composite was fabricated by ball milling of the mixture for 70 h and then sintering at 5 GPa, 1300 deg. C. The composite has micro-hardness of 8.8 GPa and electrical resistivity of 2 x 10{sup -4} {omega} cm. The formation mechanism of the composite was discussed based on thermodynamics and kinetics.

  19. Characterization of pressure-wave propagation during the condensation of R404A and R134a refrigerants in pipe mini-channels that undergo periodic hydrodynamic disturbances

    International Nuclear Information System (INIS)

    Highlights: ► Studied the pressure wave propagation velocity during condensation of refrigerants R134a and R404A. ► Condensation process occurred in minichannels. ► In the calculations used two-phase flow model. ► Having regard to relevant flow regime obtained satisfactory agreement with experimental results of computational. -- Abstract: In the present paper, an attempt was undertaken to model the propagation of a pressure wave triggered by periodic hydrodynamic instabilities in the condensation of the R404A and R134a refrigerants in pipe mini-channels. A homogenous transient two-fluid model was used based on balance equations. The model presents the complexity of multi-phase flows. The heat exchange between the phases in the condensation process was calculated using the one-dimensional form of Fourier’s equation. The dependence which defines the interfacial the drag forces for the flow in mini-channels was also taken into consideration. The results of the numerical calculations were verified with experimental investigations and satisfactory compliance was obtained

  20. Pressure transducers

    International Nuclear Information System (INIS)

    Strain gauges pressure transducers types are presented. Models, characteristics and calibration procedures were also analysed. Initially, a theoretical study was accomplished to evaluate metallic alloys behavior on sensing elements manufacturing, and diaphragm was used as deflecting elements. Electrical models for potenciometric transducers were proposed at the beginning and subsequently comproved according our experiments. Concerning bridge transducers, existing models confirmed the conditions of linearity and sensitivity related to the electrical signal. All the work done was of help on the calibration field and pressure measurements employing unbounded strain gauge pressure transducers

  1. [Individual pressure tolerance--a "target" pressure?].

    Science.gov (United States)

    Bogdănici, C; Vancea, P P

    1999-01-01

    In literature there are many meanings for the limit between normal and pathological intraocular pressure: "normative pressure", "critic pressure", "individual tolerance pressure" and "target pressure". The aim of this paper is to demonstrate that these terms are synonymous. PMID:10756882

  2. Pressure Drop

    Science.gov (United States)

    Lawson, Mike

    2010-01-01

    Mike Lawson briefly discussed pressure drop for aerospace applications and presented short stories about adventures experienced while working at NASA and General Dynamics, including exposure to technologies like the Crew and Equipment Translation Aid (CETA) cart and the SWME.

  3. Pressure sensor

    Energy Technology Data Exchange (ETDEWEB)

    Mee, David K.; Ripley, Edward B.; Nienstedt, Zachary C.; Nienstedt, Alex W.; Howell, Jr., Layton N.

    2015-09-29

    Disclosed is a passive, in-situ pressure sensor. The sensor includes a sensing element having a ferromagnetic metal and a tension inducing mechanism coupled to the ferromagnetic metal. The tension inducing mechanism is operable to change a tensile stress upon the ferromagnetic metal based on a change in pressure in the sensing element. Changes in pressure are detected based on changes in the magnetic switching characteristics of the ferromagnetic metal when subjected to an alternating magnetic field caused by the change in the tensile stress. The sensing element is embeddable in a closed system for detecting pressure changes without the need for any penetrations of the system for power or data acquisition by detecting changes in the magnetic switching characteristics of the ferromagnetic metal caused by the tensile stress.

  4. High-pressure synthesis, structure, and characterization of a post-perovskite CaPtO3 with CaIrO3-type structure.

    Science.gov (United States)

    Inaguma, Yoshiyuki; Hasumi, Ken-ichiro; Yoshida, Masashi; Ohba, Tomonori; Katsumata, Tetsuhiro

    2008-03-17

    A new ternary platinum oxide, CaPtO3 was synthesized under a pressure of 7 GPa and a temperature of 1000 degrees C. The crystal structure of CaPtO3 was determined by Rietveld analysis of the X-ray powder diffraction data. CaPtO3 has a layered CaIrO3-type structure (orthorhombic, space group: Cmcm), which is the same as that of a post-perovskite MgSiO3 in the Earth's lower mantle. The magnetic susceptibility data indicate that the Pt ion in CaPtO3 is tetravalent in the low spin state with an electron configuration of t2g(6)eg(0)(S = 0). This finding is consistent with the insulating behavior. PMID:18269241

  5. Characterization and influencing factors of visit-to-visit blood pressure variability of the population in a northern Chinese industrial city

    Institute of Scientific and Technical Information of China (English)

    Cao Huijun; Wu Shouling; Li Shuqiang; Zhao Haiyan; Ruan Chunyu; Wu Yuntao; Xing Aijun

    2014-01-01

    Background Blood pressure variability (BPV) is a reliable prognostic factor for cardiovascular events.Currently there is a worldwide lack of large sample size studies in visit-to-visit BPV.Based on the Kailuan Study,we analyzed the visit-to-visit BPV of patients to investigate the range and influencing factors of BPV.Methods In 11 hospitals in the Kailuan Company,4 441 patients received routine health checkups.Physical examination measured blood pressure (BP),body height,body weight,and waist circumference,and body mass index was calculated.Blood samples were analyzed for plasma total cholesterol (TC),triglyceride (TG),high-density lipoprotein cholesterol (HDL-C),low-density lipoprotein cholesterol (LDL-C),fasting blood glucose (FBG),and high-sensitivity c-reactive protein (hs-CRP).Results The effect of gender on systolic BPV was investigated.The average systolic BPV was 10.35 mmHg (1 mmHg=0.133 kPa) overall,10.54 mmHg in males and 10.06 mmHg in females.Multivariate Logistic regression analysis revealed that the age (RR=1.022),systolic BP (SBP,RR=1.007),LDL-C (RR=1.098),and history of hypertension (RR=-1.273) were significant risk factors for higher systolic BPV.We found that aging (RR=1.022),increased SBP (RR=1.007),and a history of hypertension (RR=1.394) were determinants of systolic BPV in males.The risk factors for systolic BPV of females were aging (RR=1.017),increased SBP (RR=1.009),increased LDL (RR=1.136),and increased TG (RR=1.157).Conclusion Our findings indicated that the systolic BPV is closely associated with age,SBP and history of hypertension.

  6. High pressure high temperature (HPHT) synthesis and physical characterization of FeSr{sub 2}EuCu{sub 2}O{sub 8-{delta}}

    Energy Technology Data Exchange (ETDEWEB)

    Ubaldini, A. [National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)], E-mail: alberto.ubaldini@nims.go.jp; Awana, V.P.S. [National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110 012 (India); Balamurugan, S.; Takayama-Muromachi, E. [National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2007-09-01

    FeSr{sub 2}EuCu{sub 2}O{sub 8} (FeEu-1212) does not exhibit superconductivity when prepared by classical solid state route, because of iron atoms substitute partially copper atoms in the superconductive CuO{sub 2} planes. Recently, it has been found that high temperature annealing in Ar or N{sub 2} can favour the complete substitution of copper in CuO{sub 1-{delta}} chains instead of in the CuO{sub 2} planes. After this annealing, the total oxygen content of the tetragonal FeSr{sub 2}RECu{sub 2}O{sub 8} decreases and the crystal structure changes to orthorhombic. It is possible to get superconductivity with a second annealing in O{sub 2} at low temperature. In this work a different approach was tried for first time. The samples of FeSr{sub 2}EuCu{sub 2}O{sub 8-{delta}} series with {delta} = 0, 0.5, 0.75 and 1 were prepared by high pressure high temperature (HPHT) synthesis starting from a mixture of Fe{sub 2}O{sub 3}, SrO{sub 2}, Eu{sub 2}O{sub 3}, CuO and Cu. The final oxygen content was determined by the ratio between CuO and Cu. The structure of thus prepared samples changed from tetragonal for {delta} = 0 to orthorhombic for {delta} = 0.75 and 1. The iron atoms selectively occupy the CuO{sub 1-{delta}} chains, if the oxygen content is low. Superconductive properties of these materials were studied, by subjecting them to high pressure and low temperature annealing with Ag{sub 2}O{sub 2} or KClO{sub 4} as oxidizing agents.

  7. Combined UHV/high-pressure catalysis setup for depth-resolved near-surface spectroscopic characterization and catalytic testing of model catalysts

    Science.gov (United States)

    Mayr, Lukas; Rameshan, Raffael; Klötzer, Bernhard; Penner, Simon; Rameshan, Christoph

    2014-05-01

    An ultra-high vacuum (UHV) setup for "real" and "inverse" model catalyst preparation, depth-resolved near-surface spectroscopic characterization, and quantification of catalytic activity and selectivity under technologically relevant conditions is described. Due to the all-quartz reactor attached directly to the UHV-chamber, transfer of the catalyst for in situ testing without intermediate contact to the ambient is possible. The design of the UHV-compatible re-circulating batch reactor setup allows the study of reaction kinetics under close to technically relevant catalytic conditions up to 1273 K without contact to metallic surfaces except those of the catalyst itself. With the attached differentially pumped exchangeable evaporators and the quartz-microbalance thickness monitoring equipment, a reproducible, versatile, and standardised sample preparation is possible. For three-dimensional near-surface sample characterization, the system is equipped with a hemispherical analyser for X-ray photoelectron spectroscopy (XPS), electron-beam or X-ray-excited Auger-electron spectroscopy, and low-energy ion scattering measurements. Due the dedicated geometry of the X-ray gun (54.7°, "magic angle") and the rotatable sample holder, depth analysis by angle-resolved XPS measurements can be performed. Thus, by the combination of characterisation methods with different information depths, a detailed three-dimensional picture of the electronic and geometric structure of the model catalyst can be obtained. To demonstrate the capability of the described system, comparative results for depth-resolved sample characterization and catalytic testing in methanol steam reforming on PdGa and PdZn near-surface intermetallic phases are shown.

  8. Pressurized fluidized-bed hydroretorting of eastern oil shales. Volume 4, Task 5, Operation of PFH on beneficiated shale, Task 6, Environmental data and mitigation analyses and Task 7, Sample procurement, preparation, and characterization: Final report, September 1987--May 1991

    Energy Technology Data Exchange (ETDEWEB)

    1992-03-01

    The objective of Task 5 (Operation of Pressurized Fluidized-Bed Hydro-Retorting (PFH) on Beneficiated Shale) was to modify the PFH process to facilitate its use for fine-sized, beneficiated Eastern shales. This task was divided into 3 subtasks: Non-Reactive Testing, Reactive Testing, and Data Analysis and Correlations. The potential environment impacts of PFH processing of oil shale must be assessed throughout the development program to ensure that the appropriate technologies are in place to mitigate any adverse effects. The overall objectives of Task 6 (Environmental Data and Mitigation Analyses) were to obtain environmental data relating to PFH and shale beneficiation and to analyze the potential environmental impacts of the integrated PFH process. The task was divided into the following four subtasks. Characterization of Processed Shales (IGT), 6.2. Water Availability and Treatment Studies, 6.3. Heavy Metals Removal and 6.4. PFH Systems Analysis. The objective of Task 7 (Sample Procurement, Preparation, and Characterization) was to procure, prepare, and characterize raw and beneficiated bulk samples of Eastern oil shale for all of the experimental tasks in the program. Accomplishments for these tasks are presented.

  9. Reactor pressure vessel steels

    International Nuclear Information System (INIS)

    Research and development activities related to reactor pressure vessel steels during 1997 are reported. The objectives of activities of the Belgian Nuclear Research Centre SCK/CEN in this domain are: (1) to develop enhanced surveillance concepts by applying micromechanics and fracture-toughness tests to small specimens, and by performing damage modelling and microstructure characterization; (2) to demonstrate a methodology on a broad database; (3) to achieve regulatory acceptance and industrial use

  10. The pressurized water reactor

    International Nuclear Information System (INIS)

    Pressurized water reactor technology has reached a maturity that has engendered a new surge of innovation, which in turn, has led to significant advances in the technology. These advances, characterized by bold thinking but conservative execution, are resulting in nuclear plant designs which offer significant performance and safety improvements. This paper describes the innovations which are being designed into mainstream PWR technology as well as the desings which are resulting from such innovations. (author)

  11. Characterization of gamma-irradiated polyethylene terephthalate by liquid-chromatography-mass-spectrometry (LC-MS) with atmospheric-pressure chemical ionization (APCI)

    International Nuclear Information System (INIS)

    Low-molecular-weight (low-MW) constituents of polyethylene terephthalate (PET), irradiated with 6Co gamma rays at 25 and 50 kGy, were analyzed by HPLC-MS with atmospheric-pressure chemical ionization (APCI). Consistent with earlier results, the concentrations of the major compounds that are present in the non-irradiated PET do not change perceptibly. However, we find a small but significant increase in terephthalic acid ethylester, from less than 1 mg/kg in the non-irradiated control to ca. 2 mg/kg after 50 kGy, which has not been described before. The finding is important because it gives an impression of the sensitivity of the analytical method. Additionally, it shows that even very radiation-resistant polymers can form measurable amounts of low-MW radiolysis products. The potential and limitations of LC-MS for the analysis of radiolysis products and unidentified migrants are briefly discussed in the context of the question: How can we validate our analytical methods for unknown analytes?

  12. High-pressure syntheses and characterization of the rare-earth fluoride borates RE2(BO3)F3 (RE = Tb, Dy, Ho)

    International Nuclear Information System (INIS)

    The new rare-earth fluoride borates RE2(BO3)F3 (RE = Tb, Dy, Ho) were synthesized under high-pressure/high-temperature conditions of 1.5 GPa/1200 C for Tb2(BO3)F3 and 3.0 GPa/900 C for Dy2(BO3)F3 and Ho2(BO3)F3 in a Walker-type multianvil apparatus from the corresponding rare-earth sesquioxides, rare-earth fluorides, and boron oxide. The single-crystal structure determinations revealed that the new compounds are isotypic to the known rare-earth fluoride borate Gd2(BO3)F3. The new rare-earth fluoride borates crystallize in the monoclinic space group P21/c (Z = 8) with the lattice parameters a = 16.296(3), b = 6.197(2), c = 8.338(2) A, β = 93.58(3) for Tb2(BO3)F3, a = 16.225(3), b = 6.160(2), c = 8.307(2) A, β = 93.64(3) for Dy2(BO3)F3, and a = 16.189(3), b = 6.124(2), c = 8.282(2) A, β = 93.69(3) for Ho2(BO3)F3. The four crystallographically different rare-earth cations (CN = 9) are surrounded by oxygen and fluoride anions. All boron atoms form isolated trigonal-planar [BO3]3- groups. The six crystallographically different fluoride anions are in a nearly planar coordination by three rare-earth cations. (orig.)

  13. Chemical pressure

    OpenAIRE

    Hauser, Andreas; Amstutz, Nahid; Delahaye, Sandra; Sadki, Asmaâ; Schenker, Sabine; Sieber, Regula; Zerara, Mohamed

    2002-01-01

    The physical and photophysical properties of three classic transition metal complexes, namely [Fe(bpy)3]2+, [Ru(bpy)3]2+, and [Co(bpy)3]2+, can be tuned by doping them into a variety of inert crystalline host lattices. The underlying guest-host interactions are discussed in terms of a chemical pressure.

  14. Comparing Laser Desorption Ionization and Atmospheric Pressure Photoionization Coupled to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry To Characterize Shale Oils at the Molecular Level

    Science.gov (United States)

    Cho, Yunjo; Jin, Jang Mi; Witt, Matthias; Birdwell, Justin E.; Na, Jeong-Geol; Roh, Nam-Sun; Kim, Sunghwan

    2013-01-01

    Laser desorption ionization (LDI) coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to analyze shale oils. Previous work showed that LDI is a sensitive ionization technique for assessing aromatic nitrogen compounds, and oils generated from Green River Formation oil shales are well-documented as being rich in nitrogen. The data presented here demonstrate that LDI is effective in ionizing high-double-bond-equivalent (DBE) compounds and, therefore, is a suitable method for characterizing compounds with condensed structures. Additionally, LDI generates radical cations and protonated ions concurrently, the distribution of which depends upon the molecular structures and elemental compositions, and the basicity of compounds is closely related to the generation of protonated ions. This study demonstrates that LDI FT-ICR MS is an effective ionization technique for use in the study of shale oils at the molecular level. To the best of our knowledge, this is the first time that LDI FT-ICR MS has been applied to shale oils.

  15. Characterization of nonpolar lipids and steroids by using laser-induced acoustic desorption/chemical ionization, atmospheric pressure chemical ionization, and electrospray ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Z; Daiya, S; Kenttämaa, Hilkka I

    Laser-induced acoustic desorption (LIAD) combined with ClMn(H{sub 2}O){sup +} chemical ionization (CI) was tested for the analysis of nonpolar lipids and selected steroids in a Fourier-transform ion cyclotron resonance mass spectrometer (FT-ICR). The nonpolar lipids studied, cholesterol, 5α-cholestane, cholesta-3,5-diene, squalene, and β-carotene, were found to solely form the desired water replacement product (adduct-H{sub 2}O) upon reaction with the ClMn(H{sub 2}O){sup +} ions. The steroids, androsterone, dehydroepiandrosterone (DHEA), estrone, estradiol, and estriol, also form abundant adduct-H{sub 2}O ions, but less abundant adduct-2H{sub 2}O ions were also observed. Neither (+)APCI nor (+)ESI can ionize the saturated hydrocarbon lipid, cholestane. APCI successfully ionizes the unsaturated hydrocarbon lipids to form exclusively the intact protonated analytes. However, it causes extensive fragmentation for cholesterol and the steroids. The worst case is cholesterol that does not produce any stable protonated molecules. On the other hand, ESI cannot ionize any of the hydrocarbon analytes, saturated or unsaturated. However, ESI can be used to protonate the oxygen-containing analytes with substantially less fragmentation than for APCI in all cases except for cholesterol and estrone. In conclusion, LIAD/ClMn(H{sub 2}O){sup +} chemical ionization is superior over APCI and ESI for the mass spectrometric characterization of underivatized nonpolar lipids and steroids.

  16. Characterization and antimicrobial efficacy against E. coli of a helium/air plasma at atmospheric pressure created in a plastic package

    International Nuclear Information System (INIS)

    A plasma source, sustained by the application of a floating high voltage (±15 kV) to parallel-plate electrodes at 50 Hz, has been achieved in a helium/air mixture at atmospheric pressure (P = 105 Pa) contained in a zip-locked plastic package placed in the electrode gap. Some of the physical and antimicrobial properties of this apparatus were established with a view to ascertain its performance as a prototype for the disinfection of fresh produce. The current-voltage (I-V) and charge-voltage (Q-V) characteristics of the system were measured as a function of gap distance d, in the range (3 × 103 ⩽ Pd ⩽ 1.0 × 104 Pa m). The electrical measurements showed this plasma source to exhibit the characteristic behaviour of a dielectric barrier discharge in the filamentary mode and its properties could be accurately interpreted by the two-capacitance in series model. The power consumed by the discharge and the reduced field strength were found to decrease quadratically from 12.0 W to 4.5 W and linearly from 140 Td to 50 Td, respectively, in the range studied. Emission spectra of the discharge were recorded on a relative intensity scale and the dominant spectral features could be assigned to strong vibrational bands in the 2+ and 1- systems of N2 and N2+, respectively, with other weak signatures from the NO and OH radicals and the N+, He and O atomic species. Absolute spectral intensities were also recorded and interpreted by comparison with the non-equilibrium synthetic spectra generated by the computer code SPECAIR. At an inter-electrode gap of 0.04 m, this comparison yielded typical values for the electron, vibrational and translational (gas) temperatures of (4980 ± 100) K, (2700 ± 200) K and (300 ± 100) K, respectively and an electron density of 1.0 × 1017 m-3. A Boltzmann plot also provided a value of (3200 ± 200 K) for the vibrational temperature. The antimicrobial efficacy was assessed by studying the resistance of both Escherichia coli K12 its isogenic

  17. Pressurized hopper

    International Nuclear Information System (INIS)

    A Secure Automated Fuel Fabrication Line is being developed to reduce personnel exposure and to improve safeguards. Fertile and fissile fuel powders are blended in the line for making fuel pellets. A pressurized hopper was developed for use not only as a blender, but also as a storage and feeding device. It works with or without injection tubes to produce a well-blended powder with reduced agglomerate population. Results of blending experiments using dry Kaolin clay and Tempra pigment are given

  18. High Pressure Treatment in Foods

    OpenAIRE

    Edwin Fabian Torres Bello; Gerardo González Martínez; Bernadette F. Klotz Ceberio; Dolores Rodrigo; Antonio Martínez López

    2014-01-01

    High hydrostatic pressure (HHP), a non-thermal technology, which typically uses water as a pressure transfer medium, is characterized by a minimal impact on food characteristics (sensory, nutritional, and functional). Today, this technology, present in many food companies, can effectively inactivate bacterial cells and many enzymes. All this makes HHP very attractive, with very good acceptance by consumers, who value the organoleptic characteristics of products processed by this non-thermal f...

  19. High Pressure Treatment in Foods

    OpenAIRE

    Torres Bello, Edwin Fabian; González Martínez, Gerardo; Bernadette F. Klotz Ceberio; Rodrigo Aliaga, Mª Dolores; Martínez López, Antonio

    2014-01-01

    Abstract: High hydrostatic pressure (HHP), a non-thermal technology, which typically uses water as a pressure transfer medium, is characterized by a minimal impact on food characteristics (sensory, nutritional, and functional). Today, this technology, present in many food companies, can effectively inactivate bacterial cells and many enzymes. All this makes HHP very attractive, with very good acceptance by consumers, who value the organoleptic characteristics of products processed by this non...

  20. Blood Pressure Quiz

    Science.gov (United States)

    ... page please turn Javascript on. Feature: High Blood Pressure Blood Pressure Quiz Past Issues / Fall 2011 Table of Contents ... About High Blood Pressure / Treatment: Types of Blood Pressure Medications / Blood Pressure Quiz Fall 2011 Issue: Volume 6 Number ...

  1. Hypertension (High Blood Pressure)

    Science.gov (United States)

    ... right away. continue How Do Doctors Measure Blood Pressure? Blood pressure readings are fast and painless. Blood pressure ... same age, height, and gender have lower blood pressure. Blood pressure between 90% and 95% of the normal ...

  2. Blood pressure measurement

    Science.gov (United States)

    Diastolic blood pressure; Systolic blood pressure; Blood pressure reading; Measuring blood pressure ... or your health care provider will wrap the blood pressure cuff snugly around your upper arm. The ...

  3. Pressure transient in liquid lines

    International Nuclear Information System (INIS)

    The pressure surge that results from a step change of flow in liquid pipelines, commonly known as water hammer, was analyzed by an eigenfunction method. A differential-integral Pressure wave equation and a linearized velocity equation were derived from the equations of mass and momentum conservation. Waveform distortion due to viscous dissipation and pipe-wall elastic expansion is characterized by a dimensionless transmission number K. The pressure surge condition, which is mathematically singular, was used in the solution procedure. The exact solutions from numerical calculation of the differential-integral equation provide a complete Pressure transient in the pipe. The problems are also calculated With the general-purpose computer code COMMIX, which solves the exact mass conservation equation and Navier-Stokes equations. These solutions were compared with published experimental results, and agreement was good. The effect of turbulence on the pressure transient is discussed in the light of COMMIX calculational results

  4. Mycorrhizal Propagule Persistence in a Succession of Cereals in a Disturbed and Undisturbed Andisol Fertilized with Two Nitrogen Sources Persistencia de Propágulos Micorrícicos en una Sucesión de Cereales en un Andisol Disturbado y no Disturbado, Fertilizado con Dos Fuentes de Nitrógeno

    Directory of Open Access Journals (Sweden)

    Pablo Cornejo

    2009-09-01

    Full Text Available Arbuscular mycorrhizal fungi (AMF form symbiosis with plant roots, improving its establishment, nutrition, and tolerance to adverse soil conditions. In annual crop rotations, some aspects such as the type of N fertilizer and tillage system used can affect the AMF propagule density and its functionality in the following crop. To analyze the effect of the agronomic practices previously mentioned on the persistence and density of AMF propagules, a study in a succession of cereals was carried out. For this, soil previously cropped with wheat (Triticum aestivum L. and fertilized with urea (NH4+ or sodium nitrate (NO3- was disturbed in each case by simulating conventional tillage (CT or maintained without disturbing, simulating no-tillage (NT. It was then cultivated with oat (Avena sativa L. using the same N sources. Higher densities of AMF active mycelium and colonized root length in the NT soil were observed (76 and 497% higher than in CT soil, respectively, P Los hongos micorrícico-arbusculares (AMF forman simbiosis con las raíces de las plantas, favoreciendo su establecimiento, nutrición y tolerancia a condiciones adversas del suelo. En rotaciones de cultivos anuales algunos aspectos como el tipo de fertilizante nitrogenado utilizado y el sistema de labranza pueden afectar la densidad de propágulos de AMF y su funcionalidad en el cultivo siguiente. Para analizar el efecto de las prácticas agronómicas previamente mencionadas sobre la persistencia y densidad de los propágulos de AMF, se realizó un estudio en microcosmos simulando una rotación de cereales. Para esto, suelo previamente cultivado con trigo (Triticum aestivum L. y fertilizado con urea (NH4+ o nitrato de sodio (NO3- fue, en cada caso, disturbado simulando una labranza convencional (CT o mantenido sin disturbar simulando cero labranza (NT y cultivado con avena (Avena sativa L., utilizando las mismas fuentes de N. Se observaron mayores densidades de micelio activo de AMF y

  5. High Blood Pressure (Hypertension)

    Science.gov (United States)

    ... your doctor prescribes it, medicine. What Is Blood Pressure? Blood pressure is the force of blood flow inside ... Will I Know if I Have High Blood Pressure? High blood pressure is a silent problem — you won't ...

  6. Understanding Blood Pressure Readings

    Science.gov (United States)

    ... What is the AHA recommendation for healthy blood pressure? This blood pressure chart reflects categories defined by the American ... unusually low blood pressure readings. How is high blood pressure diagnosed? Your healthcare providers will want to get ...

  7. High Blood Pressure

    Science.gov (United States)

    ... Connected Home » High Blood Pressure Heath and Aging High Blood Pressure What Is Blood Pressure? Do ... high blood pressure increases as you get older. Gender. Before age 55, men have a greater chance ...

  8. High Blood Pressure

    Science.gov (United States)

    ... pressure and should be taken seriously. Over time, consistently high blood pressure weakens and damages ... of landmark NIH blood pressure study confirm that lower blood pressure target can reduce ...

  9. Bedsores (Pressure Ulcers)

    Science.gov (United States)

    ... and rashes clinical tools newsletter | contact Share | Bedsores (Pressure Ulcers) Information for adults A A A A well-defined superficial pressure ulcer. Overview Bedsores (pressure ulcers), also known as pressure ...

  10. 植物花青苷液质联用方法的分析鉴定%Golden rules of separation and characterization of plant anthocyanins by high pressure liquid chromatography-tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    张洁; 李崇晖; 王亮生; 陈峰

    2013-01-01

      花青苷(anthocyanins)是植物中广泛存在的水溶性色素,在食品加工业中具有重要的地位。花青苷与人体健康密切相关,具有较强的抗氧化、抗炎症、抗微生物、抑制血小板凝聚和抗肿瘤等功效,已作为重要的功能因子而受到广泛的关注。花青苷成分的分析鉴定是花青苷生物活性研究的基础。然而,花青苷种类繁多,结构修饰多样,同时易受环境条件的影响,难以分离鉴定。高压液相色谱-二极管阵列检测-质谱联用技术(HPLC-DAD-MS)是花青苷分析最常规的手段。本文综述了如何利用HPLC-DAD-MS快速有效分离花青苷以及结构解析的一般规律及经验,以期为高附加值资源筛选以及花青苷构效关系的进一步揭示提供重要的化学基础。%  Anthocyanins are important water-soluble pigments, which have significant influence in food processing industry. Anthocyanins have anti-oxidant, anti-inflammatory, anti-antimicrobial, inhibition of platelet aggregation and anticancer activity, and have been the focus as important functional ingredients. Separation and identification of anthocyanins are the base for studying their bioactive effects. However, the complexity and va-riety of anthocyanins make it difficult to characterize the composition of anthocyanins. High pressure liquid chromatography (HPLC) coupled with mass spectrometry has become the standard and most powerful method for routine anthocyanin analysis. This paper reviewed the golden rules for separation and identification of anthocya-nins by high pressure liquid chromatography-tandem mass spectrometry (HPLC-DAD-MS), which might provide the chemical evidence for clarification of structure-activity relationship and screening for high value-added re-sources.

  11. High-pressure optical studies

    International Nuclear Information System (INIS)

    High pressure experimentation may concern intrinsically high pressure phenomena, or it may be used to gain a better understanding of states or processes at one atmosphere. The latter application is probably more prevelant in condensed matter physics. Under this second rubric one may either use high pressure to perturb various electronic energy levels and from this pressure tuning characterize states or processes, or one can use pressure to change a macroscopic parameter in a controlled way, then measure the effect on some molecular property. In this paper, the pressure tuning aspect is emphasized, with a lesser discussion of macroscopic - molecular relationships. In rare earth chelates the efficiency of 4f-4f emission of the rare earth is controlled by the feeding from the singlet and triplet levels of the organic ligand. These ligand levels can be strongly shifted by pressure. A study of the effect of pressure on the emission efficiency permits one to understand the effect of ligand modification at one atmosphere. Photochromic crystals change color upon irradiation due to occupation of a metastable ground state. In thermochromic crystals, raising the temperature accomplishes the same results. For a group of molecular crystals (anils) at high pressure, the metastable state can be occupied at room temperature. The relative displacement of the energy levels at high pressure also inhibits the optical process. Effects on luminescence intensity are shown to be consistent. In the area of microscopic - molecular relationships, the effect of viscosity and dielectric properties on rates of non-radiative (thermal) and radiative emission, and on peak energy for luminescence is demonstrated. For systems which can emit from either of two excited states depending on the interaction with the environment, the effect of rigidity of the medium on the rate of rearrangement of the excited state is shown

  12. A ferrofluid-based wireless pressure sensor

    OpenAIRE

    Chitnis, Girish; Ziaie, Babak

    2013-01-01

    This paper presents a wireless pressure sensor design based on magnetic fluid displacement over a planar coil and its corresponding inductance change. The design of the pressure sensor is presented followed by its fabrication and characterization. Experimental results show a good correlation with a nonlinear model relating the applied pressure to the change in coil self-resonant frequency. A prototype sensor (radius = 6 mm, thickness = 2 mm) based on the above principal using an oil-based fer...

  13. High Pressure Treatment in Foods

    Directory of Open Access Journals (Sweden)

    Edwin Fabian Torres Bello

    2014-08-01

    Full Text Available High hydrostatic pressure (HHP, a non-thermal technology, which typically uses water as a pressure transfer medium, is characterized by a minimal impact on food characteristics (sensory, nutritional, and functional. Today, this technology, present in many food companies, can effectively inactivate bacterial cells and many enzymes. All this makes HHP very attractive, with very good acceptance by consumers, who value the organoleptic characteristics of products processed by this non-thermal food preservation technology because they associate these products with fresh-like. On the other hand, this technology reduces the need for non-natural synthetic additives of low consumer acceptance.

  14. Medications and Blood Pressure

    Science.gov (United States)

    ... Blood Pressure Tools & Resources Stroke More Medications and Blood Pressure Updated:Jul 6,2016 When your blood pressure ... was last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) • Why HBP ...

  15. High Blood Pressure

    Science.gov (United States)

    ... normal blood pressure 140/90 or higher is high blood pressure Between 120 and 139 for the top number, ... prehypertension. Prehypertension means you may end up with high blood pressure, unless you take steps to prevent it. High ...

  16. High blood pressure - infants

    Science.gov (United States)

    National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents. The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents. Pediatrics . ...

  17. High Blood Pressure Facts

    Science.gov (United States)

    ... Heart Disease Cholesterol Salt Million Hearts® WISEWOMAN High Blood Pressure Facts Recommend on Facebook Tweet Share Compartir ... facts about high blood pressure [PDF-255K] . High Blood Pressure in the United States About 70 million ...

  18. Preventing pressure ulcers

    Science.gov (United States)

    Pressure ulcers are also called bedsores, or pressure sores. They can form when your skin and soft tissue ... become damaged or die. When this happens, a pressure ulcer may form. You have a risk of developing ...

  19. Characterization of the flowing afterglows of an N2 O2 reduced-pressure discharge: setting the operating conditions to achieve a dominant late afterglow and correlating the NOβ UV intensity variation with the N and O atom densities

    Science.gov (United States)

    Boudam, M. K.; Saoudi, B.; Moisan, M.; Ricard, A.

    2007-03-01

    The flowing afterglow of an N2-O2 discharge in the 0.6-10 Torr range is examined in the perspective of achieving sterilization of medical devices (MDs) under conditions ensuring maximum UV intensity with minimum damage to polymer-based MDs. The early afterglow is shown to be responsible for creating strong erosion damage, requiring that the sterilizer be operated in a dominant late-afterglow mode. These two types of afterglow can be characterized by optical emission spectroscopy: the early afterglow is distinguished by an intense emission from the N_{2}^{+} 1st negative system (band head at 391.4 nm) while the late afterglow yields an overpopulation of the v' = 11 ro-vibrational level of the N2(B) state, indicating a reduced contribution from the early afterglow N2 metastable species. We have studied the influence of operating conditions (pressure, O2 content in the N2-O2 mixture, distance of the discharge from the entrance to the afterglow (sterilizer) chamber) in order to achieve a dominant late afterglow that also ensures maximum and almost uniform UV intensity in the sterilization chamber. As far as operating conditions are concerned, moving the plasma source sufficiently far from the chamber entrance is shown to be a practical means for significantly reducing the density of the characteristic species of the early afterglow. Using the NO titration method, we obtain the (absolute) densities of N and O atoms in the afterglow at the NO injection inlet, a few cm before the chamber entrance: the N atom density goes through a maximum at approximately 0.3-0.5% O2 and then decreases, while the O atom density increases regularly with the O2 percentage. The spatial variation of the N atom (relative) density in the chamber is obtained by recording the emission intensity from the 1st positive system at 580 nm: in the 2-5 Torr range, this density is quite uniform everywhere in the chamber. The (relative) densities of N and O atoms in the discharge are determined by using

  20. Pressure losses in pneumatic transport

    OpenAIRE

    Ottjes, J.A.

    1982-01-01

    A model is derived to calculate the pressure losses originating from the dilute phase pneumatic transport of coarse particles in the horizontal stationary flow regime. The model is based on the balance of drag forces and frictional forces acting on the particles during pneumatic transport. The particles are characterized by the particle terminal velocity, the particle âwall sliding friction coefficient and the coefficient of restitution between particles and wall. The influence of the inhomog...

  1. Synthesis and characterization of NaAlSi2O6 jadeite under high pressure from 4.0 GPa to 5.5 GPa

    Science.gov (United States)

    Wang, Fang Biao; Zuo, Gui Hong; Wang, Li Juan; Zheng, You Jin; Jia, Xiao Peng; Ma, Hong An

    2016-04-01

    The method of high pressure and high temperature (HPHT) has been used for the synthesis of jadeite. Through this method, the NaAlSi2O6 jadeite can be obtained in the pressure range of 4.0-5.5 GPa. All the experimental results reveal that the microstructure and properties of synthetic jadeite resemble the natural jadeite very much. The research indicates that the crystallization temperature of the synthesized NaAlSi2O6 jadeite rises with the increase of the pressure, which will help in gaining a deep understanding on the origin of natural jadeite.

  2. Non disturbing characterization and quantification of natural organic matter (NOM) contained in clay rock pore water by mass spectrometry using electro-spray and atmospheric pressure chemical ionization modes

    International Nuclear Information System (INIS)

    formation is of great importance. In this context, establishing accurate sequencing of structural units for the DOM shall be attempted. The present work is focused on small organic molecules that are present in the COx formation and that could also play a key role in the migration processes. It would be valuable to develop rapid analytical methods that require only a small sample volume and minimal pretreatment. Of particular importance is the ability to analyze bulk pore water samples as opposed to samples subjected to specific extraction techniques, fractionation, and/or concentration. Mass Spectrometry with either the Electro-Spray or the Atmospheric Pressure Chemical Ionization modes has been proved to be a powerful tool for aquatic humic substances since it allows the determination of the molecular weight distribution and the access to the different molecular weights. In this study, we have employed ESI-MS and APCI-MS to identify the chemical composition of NOM contained in the pore water from the argillite clay rock. Due to the very small quantities of COx pore water available from boreholes, these techniques are thus very suitable. The DOM in pore water has never been characterized on a well preserved pore water sample. The following aspects were considered in the present work: (1) the use of either ESI or APCI to select the most appropriated mode of ionization for providing the best information depending on the class of compound examined (2) a unique and original experimental process developed to get pore water from a core sample (3) the determination of concentration of dissolved organic matter and the evaluation of the organic matter maturity by Excitation-Emission Matrix (EEM) spectroscopy and (4) the application of the proposed instrumental methods for the characterization of organic components from natural pore waters. For the first time to our knowledge, a quite exhaustive inventory of the small organic compounds presents is given without proceeding to any

  3. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... Preventing Pressure Sores Preventing Pressure Sores Transition from Hospital to Home Transition from Hospital to Home Spasticity, Physical Therapy-Lokomat Spasticity, Physical ...

  4. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... Injury 101 The Basics of Spinal Cord Injury Rehabilitation The Basics of Spinal Cord Injury Rehabilitation Preventing Pressure Sores Preventing Pressure Sores Transition from ...

  5. Effect of Nitrogen Source on Some Rhizospheric Properties and Persistence of my Corrhizal Fungal Propagules in an Andisol Efecto de la Fuente de Nitrógeno Sobre Algunas Propiedades Rizosféricas y Persistencia de Propágulos de Hongos Micorrícicos en un Andisol

    Directory of Open Access Journals (Sweden)

    Pablo Cornejo

    2008-06-01

    Full Text Available Nitrogen fertilization influences plant growth and rhizospheric properties, affecting the functionality and persistence of arbuscular mycorrhizal fungi (AMF. In order to analyze the effect of two N-sources (NH4+ and NO3- on the persistence of AMF propagules (colonized root, mycelium and spores and some rhizospheric parameters (pH, P available, a greenhouse experiment was carried out using two wheat (Triticum aestivum L. cvs. Otto and Metrenco, which were grown in an Andisol. Plant biomass was determined at the dry grain stage (Zadocks 99, 150 days after sowing, DAS, the density of AMF propagules was determined three months later (240 DAS, and pH and available P were determined at both stages. The results showed that N-source and cultivar influenced most of the studied variables. The NO3- + Metrenco combination showed the highest values for biomass, pH, available P and AMF spores (150, 13, 5 and 375% more than NH4+ + Otto interaction, respectively; p La fertilización nitrogenada influye en el crecimiento vegetal y propiedades rizosféricas, afectando la funcionalidad y persistencia de hongos micorrícico-arbusculares (AMF. Para analizar el efecto de dos fuentes de N (NH4+ y NO3- sobre la persistencia de propágulos de AMF (raíz colonizada, esporas e hifas y algunos parámetros rizosféricos (pH, P disponible, se realizó un experimento en invernadero utilizando dos cultivares de trigo (Triticum aestivum L., cvs. Otto y Metrenco en un Andisol. La biomasa se determinó en grano seco (Zadocks 99, 150 días después de la siembra, DAS, la densidad de propágulos de AMF se determinó tres meses más tarde (240 DAS, y el pH y P disponible se determinaron en ambas etapas. Los resultados indicaron que la fuente de N y el cultivar influyeron en la mayoría de las variables estudiadas. La combinación NO3- + Metrenco presentó mayores valores de biomasa, pH, P disponible y esporas de AMF (150; 13; 5 y 375% más que la interacción NH4+ + Otto

  6. Pressure challenge test and histopathological inspections for 17 Japanese cases with clinically diagnosed delayed pressure urticaria

    OpenAIRE

    Morioke, Satoshi; Takahagi, Shunsuke; Iwamoto, Kazumasa; Shindo, Hajime; Mihara, Shoji; Kameyoshi, Yoshikazu; Hide, Michihiro

    2010-01-01

    Delayed pressure urticaria (DPU) is characterized by deep dermal wheals that appear in response to a local continuous pressure. Although it has been reported to complicate as many as 40% of cases of Caucasian patients with chronic urticaria, no definitive cases of Asian/Japanese patients have been reported in English literature. Here, we identified 17 cases of DPU, among 540 Japanese patients with urticaria (3.1%), based on careful history taking, pressure challenge test and, ideally, skin bi...

  7. Analysis of pressure fluctuations in swirling turbulent flows

    OpenAIRE

    Abry, P.; Fauve, S.; Flandrin, P; Laroche, C

    1994-01-01

    Turbulent flows display intermittent pressure drops associated with vorticity concentrations. Using wavelet transform, we characterize these low pressure events and study some of their statistical characteristics in a flow generated between the gap of two counter-rotating disks. We show that the mean frequency of intermittent pressure drops decreases with increasing Reynolds number.


  8. Pressurized-thermal-shock experiments

    International Nuclear Information System (INIS)

    The primary objective of the ORNL pressurized-thermal-shock (PTS) experiments is to verify analytical methods that are used to predict the behavior of pressurized-water-reactor vessels under these accident conditions involving combined pressure and thermal loading. The criteria on which the experiments are based are: scale large enough to attain effective flaw border triaxial restraint and a temperature range sufficiently broad to produce a progression from frangible to ductile behavior through the wall at a given time; use of materials that can be completely characterized for analysis; stress states comparable to the actual vessel in zones of potential flaw extension; range of behavior to include cleavage initiation and arrest, cleavage initiation and arrest on the upper shelf, arrest in a high K/sub I/ gradient, warm prestressing, and entirely ductile behavior; long and short flaws with and without stainless steel cladding; and control of loads to prevent vessel burst, except as desired. A PTS test facility is under construction which will enable the establishment and control of wall temperature, cooling rate, and pressure on an intermediate test vessel (ITV) in order to simulate stress states representative of an actual reactor pressure vessel

  9. Fiber bundle model under fluid pressure

    Science.gov (United States)

    Amitrano, David; Girard, Lucas

    2016-03-01

    Internal fluid pressure often plays an important role in the rupture of brittle materials. This is a major concern for many engineering applications and for natural hazards. More specifically, the mechanisms through which fluid pressure, applied at a microscale, can enhance the failure at a macroscale and accelerate damage dynamics leading to failure remains unclear. Here we revisit the fiber bundle model by accounting for the effect of fluid under pressure that contributes to the global load supported by the fiber bundle. Fluid pressure is applied on the broken fibers, following Biot's theory. The statistical properties of damage avalanches and their evolution toward macrofailure are analyzed for a wide range of fluid pressures. The macroscopic strength of the new model appears to be strongly controlled by the action of the fluid, particularly when the fluid pressure becomes comparable with the fiber strength. The behavior remains consistent with continuous transition, i.e., second order, including for large pressure. The main change concerns the damage acceleration toward the failure that is well modeled by the concept of sweeping of an instability. When pressure is increased, the exponent β characterizing the power-law distribution avalanche sizes significantly decreases and the exponent γ characterizing the cutoff divergence when failure is approached significantly increases. This proves that fluid pressure plays a key role in failure process acting as destabilization factor. This indicates that macrofailure occurs more readily under fluid pressure, with a behavior that becomes progressively unstable as fluid pressure increases. This may have considerable consequences on our ability to forecast failure when fluid pressure is acting.

  10. Fiber bundle model under fluid pressure.

    Science.gov (United States)

    Amitrano, David; Girard, Lucas

    2016-03-01

    Internal fluid pressure often plays an important role in the rupture of brittle materials. This is a major concern for many engineering applications and for natural hazards. More specifically, the mechanisms through which fluid pressure, applied at a microscale, can enhance the failure at a macroscale and accelerate damage dynamics leading to failure remains unclear. Here we revisit the fiber bundle model by accounting for the effect of fluid under pressure that contributes to the global load supported by the fiber bundle. Fluid pressure is applied on the broken fibers, following Biot's theory. The statistical properties of damage avalanches and their evolution toward macrofailure are analyzed for a wide range of fluid pressures. The macroscopic strength of the new model appears to be strongly controlled by the action of the fluid, particularly when the fluid pressure becomes comparable with the fiber strength. The behavior remains consistent with continuous transition, i.e., second order, including for large pressure. The main change concerns the damage acceleration toward the failure that is well modeled by the concept of sweeping of an instability. When pressure is increased, the exponent β characterizing the power-law distribution avalanche sizes significantly decreases and the exponent γ characterizing the cutoff divergence when failure is approached significantly increases. This proves that fluid pressure plays a key role in failure process acting as destabilization factor. This indicates that macrofailure occurs more readily under fluid pressure, with a behavior that becomes progressively unstable as fluid pressure increases. This may have considerable consequences on our ability to forecast failure when fluid pressure is acting. PMID:27078437

  11. A Markov-Switching Approach to Measuring Exchange Market Pressure

    OpenAIRE

    Francis Y Kumah

    2007-01-01

    This paper characterizes exchange market pressure as a nonlinear Markov-switching phenomenon, and examines its dynamics in response to money growth and inflation over three regimes. The empirical results identify episodes of exchange market pressure in the Kyrgyz Republic and confirm the statistical superiority of the nonlinear regime-switching model over a linear VAR version in understanding exchange market pressure. The nonlinear empirical approach adequately characterizes the data generati...

  12. Fabrication and characterization of TiCsub(1-x)Nsub(x) (0 2Bsub(2-x)Csub(x) (x = 0, 1.0, 2.0) by high-pressure hot-pressing

    International Nuclear Information System (INIS)

    High-pressure reaction sinterings of TiN-TiC and MoC-MoB systems were carried out at 3.0 GPa and 16000C for 30 min. The temperature dependences of Vickers microhardness and thermal conductivity were examined. (Auth.)

  13. Blood pressure regulation in diabetic autonomic neuropathy

    DEFF Research Database (Denmark)

    Hilsted, J

    1985-01-01

    Defective blood pressure responses to standing, exercise and epinephrine infusions have been demonstrated in diabetic patients with autonomic neuropathy. The circulatory mechanisms underlying blood pressure responses to exercise and standing up in these patients are well characterized: In both...... which may contribute to exercise hypotension in these patients. During hypoglycemia, blood pressure regulation seems intact in patients with autonomic neuropathy. This is probably due to release of substantial amounts of catecholamines during these experiments. During epinephrine infusions a substantial...... blood pressure fall ensues in patients with autonomic neuropathy, probably due to excessive muscular vasodilation. It is unresolved why blood pressure regulation is intact during hypoglycemia and severely impaired--at similar catecholamine concentrations--during epinephrine infusions....

  14. High blood pressure medications

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007484.htm High blood pressure medicines To use the sharing features on this page, please enable JavaScript. Treating high blood pressure will help prevent problems such as heart disease, ...

  15. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... Preventing Pressure Sores Preventing Pressure Sores Transition from Hospital to Home Transition from Hospital to Home Spasticity, Physical Therapy-Lokomat Spasticity, Physical Therapy-Lokomat ...

  16. Pressure vessel design manual

    CERN Document Server

    Moss, Dennis R

    2013-01-01

    Pressure vessels are closed containers designed to hold gases or liquids at a pressure substantially different from the ambient pressure. They have a variety of applications in industry, including in oil refineries, nuclear reactors, vehicle airbrake reservoirs, and more. The pressure differential with such vessels is dangerous, and due to the risk of accident and fatality around their use, the design, manufacture, operation and inspection of pressure vessels is regulated by engineering authorities and guided by legal codes and standards. Pressure Vessel Design Manual is a solutions-focused guide to the many problems and technical challenges involved in the design of pressure vessels to match stringent standards and codes. It brings together otherwise scattered information and explanations into one easy-to-use resource to minimize research and take readers from problem to solution in the most direct manner possible. * Covers almost all problems that a working pressure vessel designer can expect to face, with ...

  17. Blood Pressure Medicines

    Science.gov (United States)

    High blood pressure, also called hypertension, usually has no symptoms. But it can cause serious problems such as stroke, heart ... kidney failure. If you cannot control your high blood pressure through lifestyle changes such as losing weight and ...

  18. Hypertension (High Blood Pressure)

    Science.gov (United States)

    ... blood pressure with the development of a practical method to measure it. Physicians began to note associations between hypertension and risk of heart failure, stroke, and kidney failure. Although scientists had yet to prove that lowering blood pressure ...

  19. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... Cord Injury 101 Spinal Cord Injury 101 The Basics of Spinal Cord Injury Rehabilitation The Basics of Spinal Cord Injury Rehabilitation Preventing Pressure Sores Preventing Pressure Sores Transition ...

  20. High blood pressure

    Science.gov (United States)

    ... you are at risk for: Bleeding from the aorta, the large blood vessel that supplies blood to ... tests Blood pressure check Blood pressure References American Diabetes Association. Standards of medical care in diabetes-2015 ...

  1. Pressure surge attenuator

    Science.gov (United States)

    Christie, Alan M.; Snyder, Kurt I.

    1985-01-01

    A pressure surge attenuation system for pipes having a fluted region opposite crushable metal foam. As adapted for nuclear reactor vessels and heads, crushable metal foam is disposed to attenuate pressure surges.

  2. [Ambulatory invasive and noninvasive blood pressure monitoring].

    Science.gov (United States)

    Bachmann, K; Wortmann, A; Engels, G

    1989-08-01

    Indirect arterial blood pressure measurement has not changed substantially since its introduction by Riva-Rocci in 1986, Korotkoff in 1905 and Recklinghausen in 1906. Random measurements in the clinic or practice reflect only incompletely the dynamic nature of the blood pressure. Blood pressure recordings by patients themselves have provided more information through better temporal resolution, however, exact characterization of the pressure response throughout the entire day and, in particular, during physical exertion are not enabled; the latter are especially important with regard to diagnosis and treatment of hypertension. In 1966, therefore, radiotelemetric transmission of direct, continuously-measured arterial blood pressure was developed which enabled beat-to-beat registration of blood pressure, outside the laboratory, during normal daily life and sport activities. The initial results showed a marked variability of the blood pressure during the course of the day (Figure 1). Excessive blood pressure increases were observed during exposure to cold, static and dynamic exercise and to a lesser degree during automobile driving and exposure to heat (Figure 3). Recording of the pressure curves via transmission by radiotelemetry shows a high degree of accuracy and temporal resolution, spatial and situational freedom but is invasive and costly in terms of personnel. The same holds true for direct continuous blood pressure registration and storage on a portable tape recorder. Portable, automatic blood pressure measuring units for ambulatory monitoring employ indirect auscultatory or oscillometric recording with a cuff. As compared with the radiotelemetric direct continuous blood pressure measuring method, the indirect method has subordinate temporal resolution, that is, the measurements are only intermittent.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2676813

  3. Dynamic Pressure Difference Microphones

    Science.gov (United States)

    Werner, E.

    A microphone with a diaphragm that is exposed to the sound field only on one side responds essentially to the sound pressure. This quantity is a scalar, and thus, pressure microphones are essentially omnidirectional (see Chapter 66). However, directional microphones are useful because they make it possible to focus on a source and suppress background noise from other directions. Most directional microphones respond to the gradient of the sound pressure, to combinations of the sound pressure and its gradient, or to combinations of higher order spatial derivatives of the sound pressure.

  4. All-plastic fiber-based pressure sensor

    DEFF Research Database (Denmark)

    Bundalo, Ivan-Lazar; Lwin, Richard; Leon-Saval, Sergio;

    2016-01-01

    We present a feasibility study and a prototype of an all-plastic fiber-based pressure sensor. The sensor is based on long period gratings inscribed for the first time to the best of our knowledge by a CO2 laser in polymethyl methacrylate (PMMA) microstructured fibers and coupled to a pod......-like transducer that converts pressure to strain. The sensor prototype was characterized for pressures up to 150 mbars, and various parameters related to its construction were also characterized in order to enhance sensitivity. We consider this sensor in the context of future applications in endoscopic pressure...... sensors....

  5. Effect of ageing on survival of benthic diatom propagules

    Digital Repository Service at National Institute of Oceanography (India)

    Anil, A.C.; Mitbavkar, S.; DeSilva, M.S.; Hegde, S.; DeCosta, P.M.; Meher, S.S.; Banerjee, D.

    method -MPN) (Imai et al., 1984; Yamochi, 1989; Imai et al., 1990; Ishikawa and Tamaguchi, 1994; Itakura et al., 1997) was employed for quantification of diatom flora. An appropriate amount (1 g wet weight) of sediment was suspended in f/2 medium... prepared in autoclaved, filtered, aged seawater (Guillard and Ryther, 1962) at a concentration of 0.1 g wet weight ml-1. This stock was subjected to serial ten-fold dilution (10-1 to 10-5) with the culture medium. 1 ml aliquots of diluted suspensions...

  6. Brave new propagules: terrestrial embryos in anamniotic eggs.

    Science.gov (United States)

    Martin, K L; Carter, A L

    2013-08-01

    A surprisingly large number of fish and amphibian species reproduce terrestrially despite the absence of the key evolutionary innovation of the amniotic egg. In contrast with shelled eggs of reptiles and birds, eggs of teleost fish and amphibians are typically much smaller and enclosed in relatively simple chorionic membranes. Incubation times may be brief or prolonged, and resultant hatchlings typically require the return to an aquatic habitat. Advantages of terrestrial incubation include the increased availability of warmer temperatures and avoidance of aquatic hypoxia, whereas disadvantages include desiccation, exposure to novel predators, and the risk of hatching into a hostile habitat. Hatching may be environmentally cued. Use of energy in the yolk may require trade-offs between growth of the embryo and extended incubation, as exemplified by a case study of the California Grunion. The physical challenges of terrestrial incubation, constraints for hatching, effects of egg size, and parental care are explored. Eight different types of early life history among anamniotic embryos incubating in a terrestrial environment are identified, with examples of these alternate routes to the invasion of land by vertebrates. PMID:23604618

  7. Pressure measuring probe

    Science.gov (United States)

    Ashby, George C., Jr. (Inventor)

    1988-01-01

    The invention is a probe for measuring changes in pressure in a high velocity fluid stream over and adjacent to the surface of an object. The probe is formed of an exterior housing having a closed pressure chamber in which a piezoelectric pressure transducer is mounted. An open connector tube having a probe tip passes a portion of the fluid stream into the closed pressure chamber; any change of pressure within, which requires a settling-time to appear in the closed pressure chamber, is inversely proportional to the cross-sectional area of the connector tube. A cooling chamber formed around the pressure chamber is connected to a source of cooling fluid by means of inlet and outlet tubes.

  8. An electrokinetic pressure sensor

    International Nuclear Information System (INIS)

    A new concept for a micro pressure sensor is demonstrated. The pressure difference between the inlet and the outlet of glass nanochannels is obtained by measuring the electrokinetically generated electric potential. To demonstrate the proposed concept, experimental investigations are performed for 100 nm wide nanochannels with sodium chloride solutions having various concentrations. The proposed pressure sensor is able to measure the pressure difference within a 10% deviation from linearity. The sensitivity of the electrokinetic pressure sensor with 10−5 M sodium chloride solution is 18.5 µV Pa−1, which is one order of magnitude higher than that of typical diaphragm-based pressure sensors. A numerical model is presented for investigating the effects of the concentration and the channel width on the sensitivity of the electrokinetic pressure sensor. Numerical results show that the sensitivity increases as the concentration decreases and the channel width increases

  9. Pressure locking test results

    Energy Technology Data Exchange (ETDEWEB)

    DeWall, K.G.; Watkins, J.C.; McKellar, M.G.; Bramwell, D. [Idaho National Engineering Lab., Idaho Falls, ID (United States)] [and others

    1996-12-01

    The U.S. Nuclear Regulatory Commission (NRC), Office of Nuclear Regulatory Research, is funding the Idaho National Engineering Laboratory (INEL) in performing research to provide technical input for their use in evaluating responses to Generic Letter 95-07, {open_quotes}Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves.{close_quotes} Pressure locking and thermal binding are phenomena that make a closed gate valve difficult to open. This paper discusses only the pressure locking phenomenon in a flexible-wedge gate valve; the authors will publish the results of their thermal binding research at a later date. Pressure locking can occur when operating sequences or temperature changes cause the pressure of the fluid in the bonnet (and, in most valves, between the discs) to be higher than the pressure on the upstream and downstream sides of the disc assembly. This high fluid pressure presses the discs against both seats, making the disc assembly harder to unseat than anticipated by the typical design calculations, which generally consider friction at only one of the two disc/seat interfaces. The high pressure of the bonnet fluid also changes the pressure distribution around the disc in a way that can further contribute to the unseating load. If the combined loads associated with pressure locking are very high, the actuator might not have the capacity to open the valve. The results of the NRC/INEL research discussed in this paper show that the relationship between bonnet pressure and pressure locking stem loads appears linear. The results also show that for this valve, seat leakage affects the bonnet pressurization rate when the valve is subjected to thermally induced pressure locking conditions.

  10. Development of Zirconium alloys (for pressure tubes)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Suk; Kwon, Sang Chul; Choo, Ki Nam; Jung, Chung Hwan; Yim, Kyong Soo; Kim, Sung Soo; Baek, Jong Hyuk; Jeong, Yong Hwan; Kim, Kyong Ho; Cho, Hae Dong [Korea Atomic Energy Research Inst., Daeduk (Korea, Republic of); Hwang, S. K.; Kim, M. H. [Inha Univ., Incheon (Korea, Republic of); Kwon, S. I [Korea Univ., Seoul (Korea, Republic of); Kim, I. S. [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of)

    1997-09-01

    The objective of this research is to set up the basic technologies for the evaluation of pressure tube integrity and to develop improved zirconium alloys to prevent pressure tube failures due to DHC and hydride blister caused by excessive creep-down of pressure tubes. The experimental procedure and facilities for characterization of pressure tubes were developed. The basic research related to a better understanding of the in-reactor performances of pressure tubes leads to noticeable findings for the first time : the microstructural effect on corrosion and hydrogen pick-up behavior of Zr-2.5Nb pressure tubes, texture effect on strength and DHC resistance and enhanced recrystallization by Fe in zirconium alloys and etc. Analytical methodology for the assessment of pressure tubes with surface flaws was set up. A joint research is being under way with AECL to determine the fracture toughness of O-8 at the EOL (End of Life) that had been quadruple melted and was taken out of the Wolsung Unit-1 after 10 year operation. In addition, pressure tube with texture controlled is being made along with VNINM in Russia as a joint project between KAERI and Russia. Finally, we succeeded in developing 4 different kinds of zirconium alloys with better corrosion resistance, low hydrogen pickup fraction and higher creep strength. (author). 121 refs., 65 tabs., 260 figs

  11. High Temperature Dynamic Pressure Measurements Using Silicon Carbide Pressure Sensors

    Science.gov (United States)

    Okojie, Robert S.; Meredith, Roger D.; Chang, Clarence T.; Savrun, Ender

    2014-01-01

    Un-cooled, MEMS-based silicon carbide (SiC) static pressure sensors were used for the first time to measure pressure perturbations at temperatures as high as 600 C during laboratory characterization, and subsequently evaluated in a combustor rig operated under various engine conditions to extract the frequencies that are associated with thermoacoustic instabilities. One SiC sensor was placed directly in the flow stream of the combustor rig while a benchmark commercial water-cooled piezoceramic dynamic pressure transducer was co-located axially but kept some distance away from the hot flow stream. In the combustor rig test, the SiC sensor detected thermoacoustic instabilities across a range of engine operating conditions, amplitude magnitude as low as 0.5 psi at 585 C, in good agreement with the benchmark piezoceramic sensor. The SiC sensor experienced low signal to noise ratio at higher temperature, primarily due to the fact that it was a static sensor with low sensitivity.

  12. Characterization of the pressure wave originating in the explosion of an extended heavy gas cloud: critical analysis of the treatment of its propagation in air and interaction with obstacles

    International Nuclear Information System (INIS)

    The protection of nuclear power plants against external explosions of heavy gas clouds is a relevant topic of nuclear safety studies. The ultimate goal of such studies is to provide realistic inputs for the prediction of structure loadings and transient response. To obtain those inputs, relatively complex computer codes have been constructed to describe the propagation in air of strong perturbations due to unconfined gas cloud explosions. A detailed critical analysis of those codes is presented. In particular, the relative errors on wave speed, induced flow velocity, as well as on reflected wave speed and overpressure, respectively due to the use of a simplified non-linear isentropic approximation and of linear acoustic models, are estimated as functions of the overpressure of the incident pulse. The ability of the various models to accurately predict the time and distance required for sharp pressure front formation is discussed. Simple computer codes using implicit finite-difference discretizations are proposed to compare the results obtained with the various models for spherical wave propagation. Those codes are also useful to study the reflection of the waves on an outer spherical flexible wall and to investigate the effect of the elasticity and damping coefficients of the wall on the characteristics of the reflected pressure pulse

  13. Measurement of endolymphatic pressure.

    Science.gov (United States)

    Mom, T; Pavier, Y; Giraudet, F; Gilain, L; Avan, P

    2015-04-01

    Endolymphatic pressure measurement is of interest both to researchers in the physiology and pathophysiology of hearing and ENT physicians dealing with Menière's disease or similar conditions. It is generally agreed that endolymphatic hydrops is associated with Menière's disease and is accompanied by increased hydrostatic pressure. Endolymphatic pressure, however, cannot be measured precisely without endangering hearing, making the association between hydrops and increased endolymphatic pressure difficult to demonstrate. Several integrated in vivo models have been developed since the 1960s, but only a few allow measurement of endolymphatic hydrostatic pressure. Models associating measurement of hydrostatic pressure and endolymphatic potential and assessment of cochlear function are of value to elucidate the pathophysiology of endolymphatic hydrops. The present article presents the main types of models and discusses their respective interest. PMID:25467202

  14. Pressure cryocooling protein crystals

    Science.gov (United States)

    Kim, Chae Un; Gruner, Sol M.

    2011-10-04

    Preparation of cryocooled protein crystal is provided by use of helium pressurizing and cryocooling to obtain cryocooled protein crystal allowing collection of high resolution data and by heavier noble gas (krypton or xenon) binding followed by helium pressurizing and cryocooling to obtain cryocooled protein crystal for collection of high resolution data and SAD phasing simultaneously. The helium pressurizing is carried out on crystal coated to prevent dehydration or on crystal grown in aqueous solution in a capillary.

  15. Atmospheric pressure X-ray photoelectron spectroscopy apparatus: Bridging the pressure gap

    OpenAIRE

    Velasco-Vélez, J.; Pfeifer, V.; Hävecker, M.; R. Wang; Centeno, A.; Zurutuza, A.; Algara-Siller, G.; Stotz, E.; Skorupska, K.; Teschner, D; Kube, P.; Braeuninger-Weimer, P.; Hofmann, S.; Schlögl, R.; Knop-Gericke, A.

    2016-01-01

    One of the main goals in catalysis is the characterization of solid/gas interfaces in a reaction environment. The electronic structure and chemical composition of surfaces become heavily influenced by the surrounding environment. However, the lack of surface sensitive techniques that are able to monitor these modifications under high pressure conditions hinders the understanding of such processes. This limitation is known throughout the community as the “pressure gap”. We have developed a nov...

  16. Controlling your high blood pressure

    Science.gov (United States)

    ... that is healthy for you. Checking Your Blood Pressure Your blood pressure can be measured at many places, including: ... Alternative Names Controlling hypertension Images Taking your blood pressure at home Blood pressure check Low sodium diet References American Diabetes ...

  17. What Is High Blood Pressure?

    Science.gov (United States)

    ... also known as blood vessels and capillaries. The pressure --- blood pressure --- is the result of two forces. The ... was last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) Introduction What ...

  18. High Blood Pressure Fact Sheet

    Science.gov (United States)

    ... much alcohol. Signs and Symptoms of High Blood Pressure High blood pressure usually has no warning signs or symptoms , ... they are at high risk for high blood pressure . Blood Pressure Levels Normal systolic: less than 120 mmHg ...

  19. ORANGE JUICE AND BLOOD PRESSURE

    OpenAIRE

    M. F. VALIM; Barros, S.

    2009-01-01

    Blood pressure is the force of blood against artery walls. It is measured in millimeters of mercury (mm Hg) and recorded as two numbers: systolic pressure (as the heart contracts) over diastolic pressure (as the heart relaxes between beats). High blood pressure (hypertension) is defined as chronically elevated high blood pressure, with systolic blood pressure (SBP) of 140 mm Hg or greater, and diastolic blood pressure (DBP) of 90 mm Hg or greater. High blood pressure ...

  20. In situ characterization of strontium surface segregation in epitaxial La0.7Sr0.3MnO3 thin films as a function of oxygen partial pressure

    International Nuclear Information System (INIS)

    Using in situ synchrotron measurements of total reflection x-ray fluorescence, we find evidence of strontium surface segregation in (001)-oriented La0.7Sr0.3MnO3 thin films over a wide range of temperatures (25-900 deg. C) and oxygen partial pressures (pO2=0.15-150 Torr). The strontium surface concentration is observed to increase with decreasing pO2, suggesting that the surface oxygen vacancy concentration plays a significant role in controlling the degree of segregation. Interestingly, the enthalpy of segregation becomes less exothermic with increasing pO2, varying from -9.5 to -2.0 kJ/mol. In contrast, the La0.7Sr0.3MnO3 film thickness and epitaxial strain state have little impact on segregation behavior

  1. High pressure synthesis and characterization of single crystalline YBa2Cu4O8(Tc=80 K) and Y2Ba4Cu7O15±χ (14 K ≤ Tc ≤ 94 K)

    International Nuclear Information System (INIS)

    The merits of the high oxygen pressure synthesis of the YBaCuO oxides and the advantages of a two-chamber autoclave are briefly reviewed. The P-T-x and the flux P-T phase diagrams are presented for the first time. The P-T-x diagram shows the P-T cuts across the compositions 123, 123.5 and 124; the 123 is not stable in the low temperature region and the 123.5 must be cooled through the stability range of 124, with the corresponding implications. The flux P-T diagram shows the fields of crystallisation under high oxygen pressure of the above three HTc-phases. Crystallization experiments give some first results about the complex growth mechanism of 124 and 123.5, in which also the vapour phase seems to be important. A brief survey of the physical properties of the double chain compounds is also given: STM investigations show that micron range areas of as grown surfaces are atomically smooth with perfect singular steps with unit cell height. Although the Tc of the 124 crystals is 7-9 K lower than that of the ceramic (81 K) - probably due to traces of aluminum - the diamagnetic transition of single crystals is very steep (ΔT=2 K). Due to the thermodynamic stability of the double chains, 124 and 123.5 do not have a-b twins and, therefore, are ideal for measurements of anisotropy. Transport and optical properties show an anisotropy of 3-5. Electronic Raman scattering in single crystals of 124 shows the existence of two gaps, attributed to the chains and the plains. Also the critical fields Hc1 and Hc2 of 124 have been measured and found approx. 3 times lower than those of 123. This means that the coherence length is also longer in 124. (orig.)

  2. A Micromachined Pressure Sensor with Integrated Resonator Operating at Atmospheric Pressure

    Directory of Open Access Journals (Sweden)

    Sen Ren

    2013-12-01

    Full Text Available A novel resonant pressure sensor with an improved micromechanical double-ended tuning fork resonator packaged in dry air at atmospheric pressure is presented. The resonator is electrostatically driven and capacitively detected, and the sensor is designed to realize a low cost resonant pressure sensor with medium accuracy. Various damping mechanisms in a resonator that is vibrating at atmospheric pressure are analyzed in detail, and a formula is developed to predict the overall quality factor. A trade-off has been reached between the quality factor, stress sensitivity and drive capability of the resonator. Furthermore, differential sense elements and the method of electromechanical amplitude modulation are used for capacitive detection to obtain a large signal-to-noise ratio. The prototype sensor chip is successfully fabricated using a micromachining process based on a commercially available silicon-on-insulator wafer and is hermetically encapsulated in a custom 16-pin Kovar package. Preliminary measurements show that the fundamental frequency of the resonant pressure sensor is approximately 34.55 kHz with a pressure sensitivity of 20.77 Hz/kPa. Over the full scale pressure range of 100–400 kPa and the whole temperature range of −20–60 °C, high quality factors from 1,146 to 1,772 are obtained. The characterization of the prototype sensor reveals the feasibility of a resonant pressure sensor packaged at atmospheric pressure.

  3. Preventing High Blood Pressure

    Science.gov (United States)

    ... Heart Disease Cholesterol Salt Million Hearts® WISEWOMAN Preventing High Blood Pressure: Healthy Living Habits Recommend on Facebook Tweet Share ... meal and snack options can help you avoid high blood pressure and its complications. Be sure to eat plenty ...

  4. Coping With Inflation Pressures

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The pressure of higher prices is a major problem confronting the Chinese economy"We will be facing fairly great price pressures in 2008,"said Xie Fuzhan,Director of the National Bureau of Statistics(NBS),on January 24."Even if there are no new fac- tors causing price hikes,the inertia from the rises in 2007 is still devastating."

  5. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... Injury Coping with a New Injury Adjusting to Social Life in a Wheelchair Adjusting to Social Life in a Wheelchair Substance Abuse and Spinal ... sore required? How long is the typical healing time for a pressure sore? Why do some pressure ...

  6. Pressure surge attenuator

    International Nuclear Information System (INIS)

    A pressure surge attenuation arrangement comprises crushable metal foam disposed adjacent regions adapted to be expanded by a pressure surge. In a pipe system such region consists of a thin walled inner pipe surrounded by a housing with crushable metal foam disposed in the space between the housing and the inner pipe. (author)

  7. Neonatal Pressure Ulcer Prevention.

    Science.gov (United States)

    Scheans, Patricia

    2015-01-01

    The incidence of pressure ulcers in acutely ill infants and children ranges up to 27 percent in intensive care units, with a range of 16-19 percent in NICUs. Anatomic, physiologic, and developmental factors place ill and preterm newborns at risk for skin breakdown. Two case studies illustrate these factors, and best practices for pressure ulcer prevention are described. PMID:26803094

  8. Effect of pressure on the crystallization behaviour of polyethylene terephthalate

    CERN Document Server

    Li Li; Huang Rui

    2002-01-01

    Crystallized polyethylene terephthalate (PET) samples were obtained at high pressures of 200-400 MPa at a temperature of 603 K, and another group of the samples were made at pressures of 250-350 MPa and different temperatures with a fixed supercooling. The samples were investigated by means of differential scanning calorimetry and scanning electron microscopy. Characterization results suggested that high pressure could increase the crystallization rate and promote the thickening process of PET lamellar crystals.

  9. Yield and nutritive components of taro as a function of propagule type in a hydromorfic soil of South Mato Grosso Pantanal/ Produção e composição nutritiva de taro em função do propágulo, em solo hidromórfico do Pantanal Sul-Mato-Grossense

    Directory of Open Access Journals (Sweden)

    Priscila Aiko Hiane

    2006-06-01

    Full Text Available The objective of this work was to determine yield and nutritive components of taro rhizomes in hydromorfic soil conditions of South Mato Grosso Pantanal. Chinês and Macaquinho taros were evaluated. They were propagated by rhizomes of big and small classes, as whole and half types, arranged as 2 x 2 x 2 factorial scheme in randomized block experimental design, with four replications. Final population, plant height and fresh mass of leaves and of corms of Chinês taro were significantly superior than ‘Macaquinho’. Regarding to propagule classes used for propagation, big rhizome was the best. The use of whole rhizomes was significantly better than cut rhizomes regarding to final population and yield of fresh mass of corms (RM and it was similar for plant height and yield of fresh mass of leaves and of cormels (RF. In relation to nutritive compound of rhizomes, RM and RF had contents which were characteristics of the clone. RM and RF of both two clones showed higher contents of fix mineral residue, proteins and carbohydrates and they have smaller contents of lipids and of fibers, as well of total caloric value, than of corn. RM and RF of both two clones had smaller contents of lipids, carbohydrates and TCV in relation to wheat flour.O objetivo do trabalho foi determinar a produtividade e a composição nutritiva dos rizomas de taro, em condições de solo hidromórfico do pantanal sul-mato-grossense. Foram avaliados os taros Chinês e Macaquinho, propagados por rizomas das classes grande e pequena, como tipos inteiros e cortados no meio, arranjados em esquema fatorial 2x2x2, no delineamento experimental de blocos casualizados, com quatro repetições. A população final, altura das plantas e massa fresca das folhas e dos rizomas-mãe do taro Chinês foi significativamente superior à do Macaquinho. Quanto às classes de propágulos utilizados para a propagação, foi melhor o uso de rizomas grandes. O uso de rizomas inteiros foi

  10. High-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry and gas chromatography-flame ionization detection characterization of Delta5-polyenoic fatty acids in triacylglycerols from conifer seed oils.

    Science.gov (United States)

    Lísa, Miroslav; Holcapek, Michal; Rezanka, Tomás; Kabátová, Nadezda

    2007-03-30

    Edible conifer seeds can serve as a source of triacylglycerols (TGs) with unusual Delta5 unsaturated polymethylene interrupted fatty acids (UPIFAs), such as cis-5,9-octadecadienoic (taxoleic), cis-5,9,12-octadecatrienoic (pinolenic), cis-5,11-eicosadienoic (keteleeronic) and cis-5,11,14-eicosatrienoic acids (sciadonic). Conifer seed oils from European Larch (Larix decidua), Norway Spruce (Picea abies) and European Silver Fir (Abies alba) have been analyzed by non-aqueous reversed-phase high-performance liquid chromatography (NARP-HPLC) with atmospheric pressure chemical ionisation (APCI)-MS detection. The influence of different positions of double bonds in Delta5-UPIFAs on the retention and fragmentation behavior is described and used for the successful identification of TGs in each oil. TGs containing Delta5-UPIFAs have a higher retention in comparison with common TGs found in plant oils with single methylene interrupted Delta6(9)-FAs and also significantly changed relative abundances of fragment ions in APCI mass spectra. Results obtained from HPLC/MS analyses are supported by validated GC/FID analyses of fatty acid methyl esters after the transesterification. The total content of Delta5-UPIFAs is about 32% for European Larch, 27% for Norway Spruce and 20% for European Silver Fir. In total, 20 FAs with acyl chain lengths from 16 to 24 carbon atoms and from 0 to 3 double bonds have been identified in 64 triacylglycerols from 3 conifer seed oils. PMID:17307191

  11. High-pressure syntheses and characterization of the rare-earth fluoride borates RE{sub 2}(BO{sub 3})F{sub 3} (RE = Tb, Dy, Ho)

    Energy Technology Data Exchange (ETDEWEB)

    Hinteregger, Ernst; Pitscheider, Almut; Wurst, Klaus; Heymann, Gunter; Huppertz, Hubert [Innsbruck Univ. (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie; Enders, Michael [Innsbruck Univ. (Austria). Inst. fuer Pharmazie

    2013-11-15

    The new rare-earth fluoride borates RE{sub 2}(BO{sub 3})F{sub 3} (RE = Tb, Dy, Ho) were synthesized under high-pressure/high-temperature conditions of 1.5 GPa/1200 C for Tb{sub 2}(BO{sub 3})F{sub 3} and 3.0 GPa/900 C for Dy{sub 2}(BO{sub 3})F{sub 3} and Ho{sub 2}(BO{sub 3})F{sub 3} in a Walker-type multianvil apparatus from the corresponding rare-earth sesquioxides, rare-earth fluorides, and boron oxide. The single-crystal structure determinations revealed that the new compounds are isotypic to the known rare-earth fluoride borate Gd{sub 2}(BO{sub 3})F{sub 3}. The new rare-earth fluoride borates crystallize in the monoclinic space group P2{sub 1}/c (Z = 8) with the lattice parameters a = 16.296(3), b = 6.197(2), c = 8.338(2) A, {beta} = 93.58(3) for Tb{sub 2}(BO{sub 3})F{sub 3}, a = 16.225(3), b = 6.160(2), c = 8.307(2) A, {beta} = 93.64(3) for Dy{sub 2}(BO{sub 3})F{sub 3}, and a = 16.189(3), b = 6.124(2), c = 8.282(2) A, {beta} = 93.69(3) for Ho{sub 2}(BO{sub 3})F{sub 3}. The four crystallographically different rare-earth cations (CN = 9) are surrounded by oxygen and fluoride anions. All boron atoms form isolated trigonal-planar [BO{sub 3}]{sup 3-} groups. The six crystallographically different fluoride anions are in a nearly planar coordination by three rare-earth cations. (orig.)

  12. Microstructural characterization and model of hardening for the irradiated austenitic stainless steels of the internals of pressurized water reactors; Caracterisation microstructurale et modelisation du durcissement des aciers austenitiques irradies des structures internes des reacteurs a eau pressurisee

    Energy Technology Data Exchange (ETDEWEB)

    Pokor, C

    2003-07-01

    The core internals of Pressurized Water Reactors (PWR) are composed of SA 304 stainless steel plates and CW 316 stainless steel bolts. These internals undergo a neutron flux at a temperature between 280 deg C and 380 deg C which modifies their mechanical properties. These modifications are due to the changes in the microstructure of these materials under irradiation which depend on flux, dose and irradiation temperature. We have studied, by Transmission Electron Microscopy, the microstructure of stainless steels SA 304, CW 316 and CW 316Ti irradiated in a mixed flux reactor (OSIRIS at 330 deg C between 0,8 dpa et 3,4 dpa) and in a fast breeder reactor at 330 deg C (BOR-60) up to doses of 40 dpa. Moreover, samples have been irradiated at 375 deg C in a fast breeder reactor (EBR-II) up to doses of 10 dpa. The microstructure of the irradiated stainless steels consists in faulted Frank dislocation loops in the [111] planes of austenitic, with a Burgers vector of [111]. It is possible to find some voids in the solution annealed samples irradiated at 375 deg C. The evolution of the dislocations loops and voids has been simulated with a 'cluster dynamic' model. The fit of the model parameters has allowed us to have a quantitative description of our experimental results. This description of the microstructure after irradiation was coupled together with a hardening model by Frank loops that has permitted us to make a quantitative description of the hardening of SA 304, CW 316 and CW 316Ti stainless steels after irradiation at a certain dose, flux and temperature. The irradiation doses studied grow up to 90 dpa, dose of the end of life of PWR internals. (author)

  13. High Blood Pressure (Hypertension)

    Science.gov (United States)

    ... Radiation-Emitting Products Vaccines, Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products For Consumers Home For Consumers Consumer Information by Audience For Women High Blood Pressure (Hypertension) Share Tweet Linkedin Pin ...

  14. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... wheelchair seat cushion? What’s important to know about positioning in bed to prevent pressure sores? What is “ ... provide medical advice, recommend or endorse health care products or services, or control the information found on ...

  15. Preventing Pressure Sores

    Science.gov (United States)

    ... wheelchair seat cushion? What’s important to know about positioning in bed to prevent pressure sores? What is “ ... provide medical advice, recommend or endorse health care products or services, or control the information found on ...

  16. More Pressure on Iran

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    As the UN Security Council adopts a new resolution to pressure Iran over its nuclear activities, the country maintains a tough stance On March 24, the UN Security Council unanimously adopted a new resolution imposing tougher sanctions against Iran to

  17. A pressure regulator

    International Nuclear Information System (INIS)

    A device for regulating the pressure of a gas in a glove box comprises a resiliently biassed pressure sensitive diaphragm and a spool valve operable by deflection of the diaphragm. The diaphragm is arranged to be exposed on one side to atmospheric pressure and on the other side to the pressure of the gas in the glove box, and the spool valve is used to control simultaneously the rates at which gas is pumped in and out of the glove box. The valve spool has two axially spaced circumferential grooves A, B which provide communication between conduits C, D and E, F respectively, the flow control along each path being effected by means of apertures in a sleeve within which the spool slides. (author)

  18. Critical CRBR core pressure

    International Nuclear Information System (INIS)

    The conditions are detailed under which gas pressure will cause or initiate failure in the structural containment of the fuel core. The Clinch River Breeder Reactor Plant is the prototype structure. Two general classes of problems have been studied, representing two entirely distinct configurations of containment failure. The first model determines the minimum pressure to lift a portion or the entire core from its containment. The second model estimates the critical pressure above which the fuel rods interior to the hexagonal fuel can warp, leading to blockage of the gas passages. Such blockage might cause further buildup of the gas pressure to a level causing the failure of the fuel rod containment in the hexagonal fuel container

  19. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... with spinal cord injuries? What are the six stages of a pressure sore and how are they ... entire family FacingDisability is designed to provide Internet-based information and support for people with spinal cord ...

  20. Skin (Pressure) Sores

    Science.gov (United States)

    ... every 15 minutes. Use special foam or gel seat cushions to reduce pressure. Choose clothing that isn’ ... any open sore with water very carefully and cover with a bandage. Do this every time the ...

  1. Capacitance pressure sensor

    Science.gov (United States)

    Eaton, William P.; Staple, Bevan D.; Smith, James H.

    2000-01-01

    A microelectromechanical (MEM) capacitance pressure sensor integrated with electronic circuitry on a common substrate and a method for forming such a device are disclosed. The MEM capacitance pressure sensor includes a capacitance pressure sensor formed at least partially in a cavity etched below the surface of a silicon substrate and adjacent circuitry (CMOS, BiCMOS, or bipolar circuitry) formed on the substrate. By forming the capacitance pressure sensor in the cavity, the substrate can be planarized (e.g. by chemical-mechanical polishing) so that a standard set of integrated circuit processing steps can be used to form the electronic circuitry (e.g. using an aluminum or aluminum-alloy interconnect metallization).

  2. Pressure Transducer Locations

    Data.gov (United States)

    National Aeronautics and Space Administration — Files are located here, defining the locations of the pressure transducers on the HIRENASD model. These locations also correspond to the locations that analysts...

  3. Metastable Systems under Pressure

    CERN Document Server

    Rzoska, Sylwester; Mazur, Victor

    2010-01-01

    The fundamental insight and the technological & environmental relevance of metastable systems have given a strong impetus from the last decade development of extreme pressures experimental techniques, from the GPa region to the challenging negative pressures domain. The ultimate verification of theoretical models and reliable equations for portraying basic properties for such systems seems to be possible only when including temperature and pressure paths. This volume presents a set of papers related to novel findings on the glass transition phenomenon, phase transitions in liquid crystals, critical mixtures, bioliquids, geophysical system which can reveal surprising "secret" features only when using extreme pressures. This can be illustrated by the link between colloidal and molecular glassformers, the universal onset of the non-trivial dynamics in glasses, demistification of the secondary relaxation or novel findings associated with liquid - liquid near critical transitions in critical mixture, liquid cr...

  4. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... sores? What's the best way to do daily skin inspections? What are the most important things for ... in bed to prevent pressure sores? What is “skin tolerance” and how can it be increased? What ...

  5. Deuterium high pressure target

    International Nuclear Information System (INIS)

    The design of the deuterium high-pressure target is presented. The target having volume of 76 cm3 serves to provide the experimental research of muon catalyzed fusion reactions in ultra-pure deuterium in the temperature range 80-800 K under pressures of up to 150 MPa. The operation of the main systems of the target is described: generation and purification of deuterium gas, refrigeration, heating, evacuation, automated control system and data collection system

  6. Deuterium High Pressure Target

    CERN Document Server

    Perevozchikov, V; Vinogradov, Yu I; Vikharev, M D; Ganchuk, N S; Golubkov, A N; Grishenchkin, S K; Demin, A M; Demin, D L; Zinov, V G; Kononenko, A A; Lobanov, V N; Malkov, I L; Yukhimchuk, S A

    2001-01-01

    The design of the deuterium high-pressure target is presented. The target having volume of 76 cm^3 serves to provide the experimental research of muon catalyzed fusion reactions in ultra-pure deuterium in the temperature range 80-800 K under pressures of up to 150 MPa. The operation of the main systems of the target is described: generation and purification of deuterium gas, refrigeration, heating, evacuation, automated control system and data collection system.

  7. Delay Pressure Detection Method to Eliminate Pump Pressure Interference on the Downhole Mud Pressure Signals

    OpenAIRE

    Yue Shen; Ling-Tan Zhang; Shi-Li Cui; Li-Min Sheng; Lin Li; Yi-Nao Su

    2013-01-01

    The feasibility of applying delay pressure detection method to eliminate mud pump pressure interference on the downhole mud pressure signals is studied. Two pressure sensors mounted on the mud pipe in some distance apart are provided to detect the downhole mud continuous pressure wave signals on the surface according to the delayed time produced by mud pressure wave transmitting between the two sensors. A mathematical model of delay pressure detection is built by analysis of transmission path...

  8. Methodology to characterize an unsampled oil interval, integrating PVT (Pressure/Volumen/Temperature) analysis and production log; Metodologia para caracterizacao de oleo de intervalo nao-amostrado, integrando analise PVT e perfil de producao

    Energy Technology Data Exchange (ETDEWEB)

    Marcon, Diogo Reato; Souza, Ana Paula Martins de; Vieira, Alexandre J.M. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    This work presents a new methodology for characterizing an unsampled oil interval, using basically production log data and PVT analyses available in the well. The methodology was applied to a real case, where the live oil samples were collected during a well test run in three different depths, revealing some evidence of a compositional grading due to gravity. Each individual sample was a mixture of the fluid produced from the reservoir bottom to the sampling point, since the whole interval was perforated and the isolation had to be made with a packer. The first sample was corresponding to the mixture of lower and all upper oils. The other two samples are only the heavier and that oil with part of the one from the upper interval. In order to identify the fluid properties from the upper interval, needed for production development studies, the following procedure was devised: equation-of-state tuning, reproducing the sampled fluid properties; conversion of volumetric flowrates from production log into mass and molar flowrates; flowrate ratio calculation, between the upper and lower intervals; upper interval fluid composition estimative; upper interval fluid properties simulation, using the previously tuned equation-of-state, thus generating what was considered a representative, synthetic PVT analysis. (author)

  9. Home monitoring of blood pressure

    OpenAIRE

    McGrath, Barry P

    2015-01-01

    Home blood pressure monitoring is the self-measurement of blood pressure by patients. In the diagnosis and management of high blood pressure it is complementary to 24-hour ambulatory blood pressure monitoring and clinic blood pressure measurements. Home monitoring can also help to identify white-coat and masked hypertension.

  10. Blood Pressure vs. Heart Rate

    Science.gov (United States)

    ... Pressure High Blood Pressure Tools & Resources Stroke More Blood Pressure vs. Heart Rate Updated:Aug 30,2016 Blood ... was last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) Introduction What ...

  11. Tevatron quench pressure measurement

    International Nuclear Information System (INIS)

    The upcoming lower temperature/higher energy upgrade to the Fermilab Tevatron accelerator has raised questions concerning peak pressures during magnet system quenches. An experiment was performed to measure the pressure versus time at various quench energies in several devices in the Tevatron. A smaller study also looked at the temperature and mass flow rate versus time. Data was captured in a PC based circular buffer. The buffer captured ten seconds of data at 250 Hz for up to eight channels. Quenches ranging from 400 GeV to 1000 GeV were investigated. Peak pressures of 1.24 MPa (180 psia) were measured at 1000 GeV. Peak pressure increased linearly with quench energy up to 950 GeV, where it flattened off. Likewise, the time to reach peak pressure decreased linearly until 900 GeV, where it flattened off at 280 ms. The process appears to become heat transfer limited at about 900 GeV. This results in reasonable peak quench pressures at the expense of the coil reaching higher peak temperatures (not measured). The existing cryostats and relieving systems in the Tevatron will be sufficient for the new low temperature upgrade

  12. High pressure syntheses of carbonates. 4

    International Nuclear Information System (INIS)

    The ternary carbonates LiLn(CO3)2 with Ln = La to Lu and Y are synthesized from mixtures of Li2CO3 and Ln2(C2O4)3 . xH2O under 2000 bar CO2 and 500 0C. Two monoclinic types are found. They are characterized by IR and X-ray investigation and thermal decomposition. With the pressure of 200 bar and 550 0C one gets oxide-carbonates LiLnOCO3 with Ln = Sm to Lu and Y. All substances are of the same monoclinic type. Again they are characterized by IR and X-ray investigations and by thermal decomposition. The influence of the CO2 pressure and of the temperature on the formation of either LiLn(CO3)2 or LiLnOCO3 is investigated. (author)

  13. The cystogram under pressure

    International Nuclear Information System (INIS)

    Full text: The direct radionuclide cystogram (DRC) is a sensitive test for the detection of vesico-ureteric reflux (VUR), but has no recognized grading system. The X-ray micturating cystourethrogram (MCU) has an international grading system based on the calibre of the urinary system and the level of reflux reached. While reflux grades of 4 and 5 are more serious, the condition may resolve spontaneously with maturation almost irrespective of the grade. A functional grading system of the DRC has been applied for 14 years in our hospital. It is considered that reflux first occurring at low bladder volume/pressure presents a greater risk of renal insult, as reflux will occur more often. Conversely, the higher pressure grades may predict reflux that is progressing towards natural resolution. Results of 82 reflux infants first investigated under the age of 1 year (average age 0.42 years) with serial cystograms (average age 1.5 years) indicates that low pressure reflux resolves at 42%, moderate pressure 78%, high 92% and voiding grades 67%. Dual cystograms (MCU and DRC) on 62 of these infants at the same setting detected a total of 104 units of reflux, the MCU detecting only 48 and the DRC 96 units (sensitivity 46% and 92% respectively). In addition, low pressure reflux reflected a higher risk of renal insult with 44% renal dimercaptosuccinic acid (DMSA) scans reported with defects against an overall DMSA rate from all grades of 33%. The DRC volume/pressure grading offers a functional assessment with predictive value. In the young infant it would appear that the MCU has poor sensitivity for the detection of reflux and that it is the technique 'under pressure' from the direct radionuclide alternative

  14. What Causes High Blood Pressure?

    Science.gov (United States)

    ... whether imbalances in this system cause high blood pressure. Blood Vessel Structure and Function Changes in the structure ... can affect blood pressure. Genetic Causes of High Blood Pressure Much of the understanding of the body systems ...

  15. Prevention of High Blood Pressure

    Science.gov (United States)

    ... from the NHLBI on Twitter. Prevention of High Blood Pressure Healthy lifestyle habits, proper use of medicines, and ... high blood pressure or its complications. Preventing High Blood Pressure Onset Healthy lifestyle habits can help prevent high ...

  16. Medications for High Blood Pressure

    Science.gov (United States)

    ... dangerous as elevations of both systolic and diastolic pressure. Blood pressure is elevated for two main reasons: too ... and Angiotensin II receptor blockers (ARBs), reduce blood pressure by relaxing blood vessels Beta blockers, which also cause the heart ...

  17. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... of High Blood Pressure For most patients, health care providers diagnose high blood pressure when blood pressure ... painless and can be done in a health care provider’s office or clinic. To prepare for the ...

  18. Inexpensive Pressure-Relief Valve

    Science.gov (United States)

    Theordore, E. A.

    1985-01-01

    Simple device vents excess low-pressure gas. Inexpensive pressure relief valve built from polyvinylchloride pipe. Valve suitable for low pressure-- 25 to 50 cm of mercury-- and flow rates up to 14 m3/min.

  19. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... providers diagnose high blood pressure when blood pressure readings are consistently 140/90 mmHg or above. Confirming ... minutes before the test. To track blood pressure readings over a period of time, the health care ...

  20. Reotemp Pressure Indicator - Local Pressure Indication to Monitor the SCHe Supply Bottle Pressure

    International Nuclear Information System (INIS)

    These 0-3000 psig range pressure indicators are located in the SCHe helium supply lines at the pressure bottles and upstream of the PRV. These accident monitoring local pressure indicators monitor the SCHe supply bottle pressure. There is one pressure indicator for each SCHe supply (4)

  1. Advanced Diagnostics for High Pressure Spray Combustion.

    Energy Technology Data Exchange (ETDEWEB)

    Skeen, Scott A.; Manin, Julien Luc; Pickett, Lyle M.

    2014-06-01

    The development of accurate predictive engine simulations requires experimental data to both inform and validate the models, but very limited information is presently available about the chemical structure of high pressure spray flames under engine- relevant conditions. Probing such flames for chemical information using non- intrusive optical methods or intrusive sampling techniques, however, is challenging because of the physical and optical harshness of the environment. This work details two new diagnostics that have been developed and deployed to obtain quantitative species concentrations and soot volume fractions from a high-pressure combusting spray. A high-speed, high-pressure sampling system was developed to extract gaseous species (including soot precursor species) from within the flame for offline analysis by time-of-flight mass spectrometry. A high-speed multi-wavelength optical extinction diagnostic was also developed to quantify transient and quasi-steady soot processes. High-pressure sampling and offline characterization of gas-phase species formed following the pre-burn event was accomplished as well as characterization of gas-phase species present in the lift-off region of a high-pressure n-dodecane spray flame. For the initial samples discussed in this work several species were identified, including polycyclic aromatic hydrocarbons (PAH); however, quantitative mole fractions were not determined. Nevertheless, the diagnostic developed here does have this capability. Quantitative, time-resolved measurements of soot extinction were also accomplished and the novel use of multiple incident wavelengths proved valuable toward characterizing changes in soot optical properties within different regions of the spray flame.

  2. A ferrofluid-based wireless pressure sensor

    Science.gov (United States)

    Chitnis, Girish; Ziaie, Babak

    2013-12-01

    This paper presents a wireless pressure sensor design based on magnetic fluid displacement over a planar coil and its corresponding inductance change. The design of the pressure sensor is presented followed by its fabrication and characterization. Experimental results show a good correlation with a nonlinear model relating the applied pressure to the change in coil self-resonant frequency. A prototype sensor (radius = 6 mm, thickness = 2 mm) based on the above principal using an oil-based ferrofluid (50 µl, ferrite concentration 2%), a polyimide-embedded planar coil (L = 1 µH), and a 25 µm thick polyimide membrane shows a sensitivity of 3 KHz mmHg-1 with a base-line resonant frequency of f0 = 109 MHz.

  3. A ferrofluid-based wireless pressure sensor

    International Nuclear Information System (INIS)

    This paper presents a wireless pressure sensor design based on magnetic fluid displacement over a planar coil and its corresponding inductance change. The design of the pressure sensor is presented followed by its fabrication and characterization. Experimental results show a good correlation with a nonlinear model relating the applied pressure to the change in coil self-resonant frequency. A prototype sensor (radius = 6 mm, thickness = 2 mm) based on the above principal using an oil-based ferrofluid (50 µl, ferrite concentration 2%), a polyimide-embedded planar coil (L = 1 µH), and a 25 µm thick polyimide membrane shows a sensitivity of 3 KHz mmHg−1 with a base-line resonant frequency of f0 = 109 MHz. (paper)

  4. Practical means for pressure transducer response verification

    International Nuclear Information System (INIS)

    Recent concern of possible deterioration in the dynamic response of safety-related sensors has led to broadened U.S. Nuclear Regulatory Commission requirements in periodic testing. Time response checks must now extend through the entire protection channel, including the sensor element. To accommodate this requirement, a testing unit and test methodology were developed to permit practical in-situ response measurement for pressure and differential pressure transducers. Comparison tests were made against Statham strain gauges and a representative sample of pressure sensors in commercial use. These tests served to validate the test approach and also to characterize dynamic behavior of sensors employed in safety applications. Supplementary investigations of test accuracy and potential sensor-line effects were performed

  5. Ignition of PTFE-lined flexible hoses by rapid pressurization with oxygen

    Science.gov (United States)

    Janoff, Dwight; Bamford, Larry J.; Newton, Barry E.; Bryan, Coleman J.

    1989-01-01

    A high-volume pneumatic-impact system has been used to test PTFE-lined stainless steel braided hoses, in order to characterize the roles played in the mechanism of oxygen-induced ignition by impact pressure, pressurization rate, and upstream and downstream volumes of the hose. Ignitions are noted to have occurred at impact pressures well below the working pressure of the hoses, as well as at pressurization rates easily obtainable through manual operation of valves. The use of stainless steel hardlines downstream of the hose prevented ignitions at all pressures and pressurization rates; internal observations have shown evidence of shock ionization in the oxygen prior to ignition.

  6. Diffusion, peer pressure and tailed distributions

    OpenAIRE

    Cecconi, Fabio; Marsili, Matteo; Banavar, Jayanth R.; Maritan, Amos

    2002-01-01

    We present a general, physically motivated non-linear and non-local advection equation in which the diffusion of interacting random walkers competes with a local drift arising from a kind of peer pressure. We show, using a mapping to an integrable dynamical system, that on varying a parameter, the steady state behaviour undergoes a transition from the standard diffusive behavior to a localized stationary state characterized by a tailed distribution. Finally, we show that recent empirical laws...

  7. Passive blast pressure sensor

    Science.gov (United States)

    King, Michael J.; Sanchez, Roberto J.; Moss, William C.

    2013-03-19

    A passive blast pressure sensor for detecting blast overpressures of at least a predetermined minimum threshold pressure. The blast pressure sensor includes a piston-cylinder arrangement with one end of the piston having a detection surface exposed to a blast event monitored medium through one end of the cylinder and the other end of the piston having a striker surface positioned to impact a contact stress sensitive film that is positioned against a strike surface of a rigid body, such as a backing plate. The contact stress sensitive film is of a type which changes color in response to at least a predetermined minimum contact stress which is defined as a product of the predetermined minimum threshold pressure and an amplification factor of the piston. In this manner, a color change in the film arising from impact of the piston accelerated by a blast event provides visual indication that a blast overpressure encountered from the blast event was not less than the predetermined minimum threshold pressure.

  8. Downhole pressure attenuation apparatus

    International Nuclear Information System (INIS)

    This patent describes a process for preventing damage to tool strings and other downhole equipment in a well caused by pressures produced during detonation of one or more downhole explosive devices. It comprises adding to a tool string at least one pressure attenuating apparatus for attenuating the peak pressure wave and quasi-static pressure pulse produced by the explosive devices, the pressure attenuating apparatus including an initially closed relief vent including tubing means supporting a plurality of charge port assemblies each including an explosive filled shaped charge and a prestressed disc, the shaped charges interconnected by a detonating cord, the amount of explosive in each shaped charge being sufficient to rupture its associated disc without damaging surrounding tubular bodies in the well, and a vent chamber defined by the tubing means and providing a liquid free volume, and opening the relief vent substantially contemporaneously with downhole explosive device detonation by detonating the shaped charges to rupture the discs of the charge port assemblies

  9. Pressure tube type reactor

    International Nuclear Information System (INIS)

    Heretofore, a pressure tube type reactor has a problem in that the evaluation for the reactor core performance is complicate and no sufficient consideration is made for the economical property, to increase the size of a calandria tank and make the cost expensive. Then, in the present invention, the inner diameter of a pressure tube is set to greater than 50% of the lattice gap in a square lattice like arrangement, and the difference between the inner and the outer diameters of the calandria tube is set smaller than 20% of the lattice gap. Further, the inner diameter of the pressure tube is set to greater than 40% and the difference between the inner and the outer diameters of the calandria tube is set smaller than 30% of the lattice gap in a triangle lattice arrangement. Then, heavy water-to-fuel volume ratio can be determined appropriately and the value for the coolant void coefficient is made more negative side, to improve the self controllability inherent to the reactor. In particular, when 72 to 90 fuel rods are arranged per one pressure tube, the power density per one fuel rod is can be increased by about twice. Accordingly, the number of the pressure tubes can be reduced about to one-half, thereby enabling to remarkably decrease the diameter of the reactor core and to reduce the size of the calandria, which is economical. (N.H.)

  10. Pressure measurement on rotating machinery

    Science.gov (United States)

    Pemberton, Addison; Harris, Louis R.

    The objective of this paper is to describe the use of pressure scanners for measuring multiple unknown pressures in rotating machinery. Pressure scanners consist of stepper driven selector valves, which sequentially connect unknown pressures and apply these pressures to a single pressure transducer. This generates analog voltage signals which can be computerized and plotted while a pressure test is in progress. When an electrical selector switch on the same stepper driven shaft is added, thermocouple signals can be brought out of a rotating machine synchronously with pressure data.

  11. Reactor pressure boundary materials

    International Nuclear Information System (INIS)

    With a long-term operation of nuclear power plants, the component materials are degraded under severe reactor conditions such as neutron irradiation, high temperature, high pressure and corrosive environment. It is necessary to establish the reliable and practical technologies for improving and developing the component materials and for evaluating the mechanical properties. Especially, it is very important to investigate the technologies for reactor pressure boundary materials such as reactor vessel and pipings in accordance with their critical roles. Therefore, this study was focused on developing and advancing the microstructural/micro-mechanical evaluation technologies, and on evaluating the neutron irradiation characteristics and radiation effects analysis technology of the reactor pressure boundary materials, and also on establishing a basis of nuclear material property database

  12. The pressure suppression system

    International Nuclear Information System (INIS)

    Nuclear plants with boiling water reactors have a safety containment with a pressure suppression system (PSS). Proceeding on significant self-developments, today the three PSS-lines of General Electric Co. (GE), Kraftwerk Union AG (KWU) and ASEA-ATOM are predominant, which are currently represented by the MARK III type, the KWU type 72 and the BWR 75 containment. In addition, there are special developments for the nuclear ship propulsion and for the pressurized water reactors in the Soviet Union. Key design values of the PSS allow a first valuation of its loads during a hypothetical loss-of-coolant accident. (orig.)

  13. A life under pressure

    DEFF Research Database (Denmark)

    Jacobsen, Jens Christian Brings; von Holstein-Rathlou, Niels-Henrik

    2012-01-01

    Microvessels live 'a life under pressure' in several ways. In a literal sense, vessels of the microcirculation are exposed to high levels of stress caused primarily by the intravascular pressure head. In a figurative sense, the individual vessel and the microvascular network as a whole must...... stress component has a huge impact on the state of the vascular wall. It is involved as a unifying factor on vastly different timescales in processes as diverse as acute regulation of vessel diameter, structural vessel remodelling and growth or atrophy of the vascular wall. The aim of this MiniReview was...

  14. Reactor pressure vessel materials

    International Nuclear Information System (INIS)

    As a result of the popularity of the Agencies report 'Neutron Irradiation Embrittlement of Reactor Pressure Vessel Steels' of 1975, it was decided that another report on this broad subject would be of use. In this report, background and contemporary views on specially identified areas of the subject are considered as self-contained chapters, written by experts. Chapter 3 offers a detailed treatment of the selection criteria and properties of reactor pressure vessel materials. The main attention is directed towards steel and ingot making and the subsequent material processing

  15. Krypton oxides under pressure.

    Science.gov (United States)

    Zaleski-Ejgierd, Patryk; Lata, Pawel M

    2016-01-01

    Under high pressure, krypton, one of the most inert elements is predicted to become sufficiently reactive to form a new class of krypton compounds; krypton oxides. Using modern ab-initio evolutionary algorithms in combination with Density Functional Theory, we predict the existence of several thermodynamically stable Kr/O species at elevated pressures. In particular, our calculations indicate that at approx. 300 GPa the monoxide, KrO, should form spontaneously and remain thermo- and dynamically stable with respect to constituent elements and higher oxides. The monoxide is predicted to form non-molecular crystals with short Kr-O contacts, typical for genuine chemical bonds. PMID:26830129

  16. Transient flows and pressure waves in pipes

    International Nuclear Information System (INIS)

    Transient laminar flows and pressure-wave propagations in pipes connected with components, commonly known as water hammer, are analyzed. The system studied consists of a constant-pressure vessel, a uniform circular pipe, a valve between them, and a receiver vessel. A pressure-wave equation and a linearized velocity equation are derived from the equations of mass and momentum conservation. Waveform distortion due to viscous dissipation and pipe-wall elastic expansion is characterized by a dimensionless transmission number, K. The coefficients of the damping of the pressure waves were found to be related to the roots of the Bessel function J0. An exact solution of the pressure-wave equation was obtained numerically. The relationship between the distortion of a traveling wave and the transmission number K was studied. The problem is also calculated with a general-purpose computer code, COMMIX, which solves the exact mass conservation equation and Navier-Stokes equations. The COMMIX calculational results agreed well with the analytical solutions

  17. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... how is it treated? What's the most important thing to do to prevent pressure sores? A spinal cord injury affects the entire family FacingDisability is designed to provide Internet-based information and support for people with spinal ...

  18. Blood pressure and atherosclerosis

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    2010319 Effects of combined application of Xuezhikang capsule with hypotensive drugs on arterial compliance and smoothness of the dynamic blood pressure. ZHU Zongtao(朱宗涛),et al. Dept Cardiol, Centr People’s Hosp, Tengzhou 277500.Chin J Integr Tradit & West Med 2010;30

  19. PRESSURE-RESISTANT VESSEL

    NARCIS (Netherlands)

    Beukers, A.; De Jong, T.

    1997-01-01

    Abstract of WO 9717570 (A1) The invention is directed to a wheel-shaped pressure-resistant vessel for gaseous, liquid or liquefied material having a substantially rigid shape, said vessel comprising a substantially continuous shell of a fiber-reinforced resin having a central opening, an inner l

  20. Magnetic measurements under pressure

    Czech Academy of Sciences Publication Activity Database

    Zentková, M.; Arnold, Zdeněk; Mihalik, M.; Mihalik, M.; Zentko, A.; Kamarád, Jiří; Mitróová, Z.; Mat`aš, S.

    2006-01-01

    Roč. 57, 8/S (2006), s. 29-32. ISSN 1335-3632 Institutional research plan: CEZ:AV0Z10100521 Keywords : hydrostatic pressure * Prussian blue analogues * AC susceptibility * intermetallic compound * ferromagnetism * errimagnetism Subject RIV: BM - Solid Matter Physics ; Magnetism

  1. Water vapor pressure calculation.

    Science.gov (United States)

    Hall, J R; Brouillard, R G

    1985-06-01

    Accurate calculation of water vapor pressure for systems saturated with water vapor can be performed using the Goff-Gratch equation. A form of the equation that can be adapted for computer programming and for use in electronic databases is provided. PMID:4008425

  2. Radiation pressure cross section for fluffy aggregates

    International Nuclear Information System (INIS)

    We apply the discrete dipole approximation (DDA) to estimate the radiation pressure cross section for fluffy aggregates by computing the asymmetry parameter and the cross sections for extinction and scattering. The ballistic particle-cluster aggregate and the ballistic cluster-cluster aggregate consisting of either dielectric or absorbing material are considered to represent naturally existing aggregates. We show that the asymmetry parameter perpendicular to the direction of wave propagation is maximized where the wavelength is comparable to the aggregate size, which may be characterized by the area-equivalent radius or the radius of gyration rather than the volume-equivalent radius. The asymmetry parameter for the aggregate depends on the morphology of the particle, but not on the constituent material. Therefore, the dependence of the radiation pressure cross section on the material composition arises mainly from that of the extinction and scattering cross sections, in other words, the single-scattering albedo. We find that aggregates consisting of high-albedo material show a large deviation of radiation pressure from the direction of incident radiation. When the aggregates are illuminated by blackbody radiation, the deviation of the radiation pressure increases with increasing temperature of the blackbody. Since the parallel component of the radiation pressure cross section for the aggregates is smaller than that for the volume-equivalent spheres at the size parameter close to unity, the Planck-mean radiation pressure cross section for the aggregates having radius comparable to the effective wavelength of radiation shows a lower value, compared with the volume-equivalent sphere. Consequently, the slope of the radiation pressure force per mass of the particle as a function of particle mass shows a lower maximum for the aggregates than for compact spherical particles. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  3. Pressure Effect on Extensional Viscosity

    DEFF Research Database (Denmark)

    Christensen, Jens Horslund; Kjær, Erik Michael

    1999-01-01

    The primary object of these experiments was to investigate the influence of hydrostatic pressure on entrance flow. The effect of pressure on shear and extensional viscosity was evaluated using an axis symmetric capillary and a slit die where the hydrostatic pressure was raised with valves. The...... experiments show a significant increase in extensional viscosity with increasing pressure....

  4. Stroke and High Blood Pressure

    Science.gov (United States)

    ... Pressure Tools & Resources Stroke More Stroke and High Blood Pressure Updated:Jan 6,2015 Stroke is a leading ... heart disease and stroke. Start exploring today ! High Blood Pressure • Home • About High Blood Pressure (HBP) • Why HBP ...

  5. Potassium and High Blood Pressure

    Science.gov (United States)

    ... Pressure Tools & Resources Stroke More Potassium and High Blood Pressure Updated:Mar 1,2016 A diet that includes ... was last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) • Why HBP ...

  6. Types of Blood Pressure Medications

    Science.gov (United States)

    ... Blood Pressure Tools & Resources Stroke More Types of Blood Pressure Medications Updated:Aug 26,2016 Many medications known ... was last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) • Why HBP ...

  7. High Blood Pressure and Women

    Science.gov (United States)

    ... High Blood Pressure Tools & Resources Stroke More High Blood Pressure and Women Updated:Aug 13,2014 Many people ... was last reviewed on 08/04/14. High Blood Pressure • Home • About High Blood Pressure (HBP) • Why HBP ...

  8. Myths about High Blood Pressure

    Science.gov (United States)

    ... Pressure Tools & Resources Stroke More Myths About High Blood Pressure Updated:Aug 12,2014 You CAN manage your ... was last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) Introduction What ...

  9. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... pressure. Using the results of your blood pressure test, your health care provider will diagnose prehypertension or high blood pressure ... same age, gender, and height . Once your health care provider ... he or she can order additional tests to determine if your blood pressure is due ...

  10. High pressure gas metering project

    International Nuclear Information System (INIS)

    The initial research and development of a system that uses high pressure helium gas to pressurize vessels over a wide range of pressurization rates, vessel volumes, and maximum test pressures are described. A method of controlling the mass flow rate in a test vessel was developed by using the pressure difference across a capillary tube. The mass flow rate is related to the pressurization rate through a real gas equation of state. The resulting mass flow equation is then used in a control algorithm. Plots of two typical pressurization tests run on a manually operated system are included

  11. FRACTURING FLUID CHARACTERIZATION FACILITY

    Energy Technology Data Exchange (ETDEWEB)

    Subhash Shah

    2000-08-01

    Hydraulic fracturing technology has been successfully applied for well stimulation of low and high permeability reservoirs for numerous years. Treatment optimization and improved economics have always been the key to the success and it is more so when the reservoirs under consideration are marginal. Fluids are widely used for the stimulation of wells. The Fracturing Fluid Characterization Facility (FFCF) has been established to provide the accurate prediction of the behavior of complex fracturing fluids under downhole conditions. The primary focus of the facility is to provide valuable insight into the various mechanisms that govern the flow of fracturing fluids and slurries through hydraulically created fractures. During the time between September 30, 1992, and March 31, 2000, the research efforts were devoted to the areas of fluid rheology, proppant transport, proppant flowback, dynamic fluid loss, perforation pressure losses, and frictional pressure losses. In this regard, a unique above-the-ground fracture simulator was designed and constructed at the FFCF, labeled ''The High Pressure Simulator'' (HPS). The FFCF is now available to industry for characterizing and understanding the behavior of complex fluid systems. To better reflect and encompass the broad spectrum of the petroleum industry, the FFCF now operates under a new name of ''The Well Construction Technology Center'' (WCTC). This report documents the summary of the activities performed during 1992-2000 at the FFCF.

  12. RELAP-7 Pressurizer Component Development Updates

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Haihua [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, Hongbin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zou, Ling [Idaho National Lab. (INL), Idaho Falls, ID (United States); Martineau, Richard [Idaho National Lab. (INL), Idaho Falls, ID (United States); Holten, Michael [Oregon State Univ., Corvallis, OR (United States). Dept. of Nuclear Engineering and Radiation Health Physics; Wu, Qiao [Oregon State Univ., Corvallis, OR (United States). Dept. of Nuclear Engineering and Radiation Health Physics

    2016-03-01

    RELAP-7 is a nuclear systems safety analysis code being developed at the Idaho National Laboratory (INL). RELAP-7 development began in 2011 to support the Risk Informed Safety Margins Characterization (RISMC) Pathway of the Light Water Reactor Sustainability (LWRS) program. The overall design goal of RELAP-7 is to take advantage of the previous thirty years of advancements in computer architecture, software design, numerical methods, and physical models in order to provide capabilities needed for the RISMC methodology and to support nuclear power safety analysis. The code is being developed based on Idaho National Laboratory’s modern scientific software development framework – MOOSE (the Multi-Physics Object-Oriented Simulation Environment). The initial development goal of the RELAP-7 approach focused primarily on the development of an implicit algorithm capable of strong (nonlinear) coupling of the dependent hydrodynamic variables contained in the 1-D/2-D flow models with the various 0-D system reactor components that compose various boiling water reactor (BWR) and pressurized water reactor nuclear power plants (NPPs). As part of the efforts to expand the capability for PWR simulation, an equilibrium single-region pressurizer model has been implemented in RELAP-7. The pressurizer component can simulate pressure and water level change through insurge, spray, and heating processes. Two simple tests – one for insurge process and another for outsurge process have been reported to demonstrate and verify the functions of the pressurizer model. The typical single-phase PWR system model presented in the first RELAP-7 milestone report has been updated, as part of system level test for the new pressurizer model. The updated PWR system model with the pressurizer component can be used for more realistic transient simulations. The addition of the equilibrium single-region pressurizer model represents the first step of developing a suite of pressurizer models with

  13. Cerebrospinal Fluid Pressure and Glaucoma

    OpenAIRE

    Jonas, Jost B; Ningli Wang

    2013-01-01

    Eyes with normal-pressure glaucoma and those with high-pressure glaucoma can show a similar optic nerve head appearance, while eyes with vascular optic neuropathies show a markedly different optic disc appearance. Factors in addition to intraocular pressure (IOP) may thus play a role in the pathogenesis of glaucomatous optic neuropathy. Clinical and experimental studies showed that (1) physiologic associations between cerebrospinal fluid (CSF) pressure, systemic arterial blood pressure, IOP a...

  14. Measurement of Strong Shock Pressure

    OpenAIRE

    Hajime Takada; Daisuke Fujimaki; Takao Tsuboi

    1997-01-01

    This paper deals with measurement of a strong shock pressure like an imploding detonation of over 1 GPa which cannot be measured directly with currently available commercial pressure transducers. After the transfer functions of three kinds of materials were measured using a shock tube, Teflon was selected as a shock absorber. As an example of pressure beyond the limit of the pressure transducer, we tried to measure pressure at the center of an imploding detonation. From this measurement, we c...

  15. Crack initiation and arrest in a pressurized thermal shock test for a model pressure vessel made of VVER-440 reactor pressure vessel steel

    International Nuclear Information System (INIS)

    A joint pressure vessel integrity research programme involving three partners is being carried out during 1990-1994. The partners are the Central Research Institute of Structural Materials ''Prometey'' from Russia, IVO International Ltd (IVO) from Finland, and the Technical Research Centre of Finland (VTT). The main objective of the research programme is to increase the reliability of the VVER-440 reactor pressure vessel safety analysis. This is achieved by providing material property data for the VVER-440 pressure vessel steel, and by producing experimental understanding of the crack behaviour in pressurized thermal shock loading for the validation of different fracture assessment methods. The programme is divided into four parts: pressure vessel tests, material characterization, computational fracture analyses, and evaluation of the analysis methods. The testing programme comprises tests on two model pressure vessels with artificial axial outer surface flaws. The first model vessel had circumferential weld seam at the mid-length of the vessel. A special embrittling heat treatment is applied to the vessels before tests to simulate the fracture toughness at the end-of-life condition of a real reactor pressure vessel. The sixth test on the first model led to crack initiation followed by arrest. After the testing phase, material characterization was performed. Comparison of calculated and experimental data generally led to a good correlation, although the work is being continued to resolve the discrepancies between the measured initiation and arrest properties of the material. (orig.)

  16. Negative pressure device for intra-abdominal pressure reduction

    Energy Technology Data Exchange (ETDEWEB)

    David, M; Geido, D; Pracca, F; Sanchez, G; Simini, F; Zoppolo, C [Nucleo de Ingenierfa Biomedica, Universidad de la Republica O. del Uruguay, Hospital de ClInicas, Av. Italia S/N, 11600, Montevideo (Uruguay)

    2007-11-15

    A device that generates negative extra-abdominal pressure (ABDOPRE) for treatment of patients with high intra-abdominal pressure was developed. It includes pressure sensors for transducing intra-abdominal pressure through an intra-vesical catheter and negative pressure in the vacuum bell which is placed over the abdomen. By means of a control system, a pattern for reducing IAP is set, according to a clinical protocol. The external negative pressure is generated using a vacuum pump connected to the bell. The system registers the values of interest for the medical history. The system is being tested over ICU patients, registering a satisfactory IAP reduction.

  17. High pressure shaft seal

    International Nuclear Information System (INIS)

    In relation to reactor primary coolant pumps, mechanical seal assembly for a pump shaft is disclosed which features a rotating seal ring mounting system which utilizes a rigid support ring loaded through narrow annular projections in combination with centering non-sealing O-rings which effectively isolate the rotating seal ring from temperature and pressure transients while securely positioning the ring to adjacent parts. A stationary seal ring mounting configuration allows the stationary seal ring freedom of motion to follow shaft axial movement up to 3/4 of an inch and shaft tilt about the pump axis without any change in the hydraulic or pressure loading on the stationary seal ring or its carrier. (author)

  18. Radiography of pressure ulcers

    International Nuclear Information System (INIS)

    In patients with longstanding and/or deep pressure ulcers radiology is usually consulted. Survey radiography and sinography in 14 patients with pressure ulcers (6 over the tuber ischii and 8 over the femoral trochanter) were evaluated. Osteomyelitic involvement of adjacent bone was revealed in 9 patients on survey radiography. However, it was usually impossible to assess whether or not bony involvement represents healed or active osteomyelitis. Sinography did not contribute to the assessment of whether or not adjacent cortical bone was involved. However, when a fistulation to an adjacent joint was revealed this contributed substantially to the preoperative planning of resection. We therefore recommend that survey radiography and sinography should be included in the evaluation of these patients but that the results from such examinations are critically evaluated. Joint involvement should be taken seriously as progression of septic arthritis usually occurs rapidly. (orig.)

  19. Implantable micromechanical parylene-based pressure sensors for unpowered intraocular pressure sensing

    Science.gov (United States)

    Chen, Po-Jui; Rodger, Damien C.; Agrawal, Rajat; Saati, Saloomeh; Meng, Ellis; Varma, Rohit; Humayun, Mark S.; Tai, Yu-Chong

    2007-10-01

    This paper presents the first implantable, unpowered, parylene-based microelectromechanical system (MEMS) pressure sensor for intraocular pressure (IOP) sensing. From in situ mechanical deformation of the compliant spiral-tube structures, this sensor registers pressure variations without electrical or powered signal transduction of any kind. Micromachined high-aspect-ratio polymeric hollow tubes with different geometric layouts are implemented to obtain high-sensitivity pressure responses. An integrated device packaging method has been developed toward enabling minimally invasive suture-less needle-based implantation of the device. Both in vitro and ex vivo device characterizations have successfully demonstrated mmHg resolution of the pressure responses. In vivo animal experiments have also been conducted to verify the biocompatibility and functionality of the implant fixation method inside the eye. Using the proposed implantation scheme, the pressure response of the implant can be directly observed from outside the eye under visible light, with the goal of realizing convenient, direct and faithful IOP monitoring in glaucoma patients.

  20. Growth and high pressure studies of zirconium sulphoselenide single crystals

    Indian Academy of Sciences (India)

    K R Patel; R D Vaidya; M S Dave; S G Patel

    2009-11-01

    Transition metal trichalcogenides are well suited for extreme pressure lubrication. These materials being semiconducting and of layered structure may undergo structural and electronic transition under pressure. In this paper authors reported the details about synthesis and characterization of zirconium sulphoselenide single crystals. The chemical vapour transport technique was used for the growth of zirconium sulphoselenide single crystals. The energy dispersive analysis by X-ray (EDAX) gave the confirmation about the stoichiometry of the as-grown crystals and other structural characterizations were accomplished by X-ray diffraction (XRD) study. The variation of electrical resistance was monitored in a Bridgman opposed anvil set-up up to 8 GPa pressure to identify the occurrence of any structural transition. These crystals do not possess any structural transitions upto the pressure limit examined.

  1. Nozzle limit pressure

    International Nuclear Information System (INIS)

    A brief description of the static method aiming to determined the collapse load in a structure of elastic-plastic material is given. This methodology together with the Finite Element Method in the field approximation, leads to a problem of minimizing a linear function with linear constraints. The application of this technique to axissymmetrical shells submmited to axissymmetric loads is analyzed; the numerical application is done for nozzles in pipelines and pressure vessels joints. (E.G.)

  2. Hyperbaric Pressure Control System

    OpenAIRE

    Berg, Brian; Skjørten, Anders; Nicolaysen, Jonas; Skarseth, Thor Ove; Carlstedt, Jonas

    2015-01-01

    The requirement specification for the project where changed from delivery of a fully working product to contain only the design of this system due to long lead times on some of the high-pressure hydraulic parts. Three of the students where already working for FMC before project start, where two of them had experience with hydraulic Subsea Systems. Our project model where changed during the project. We started out with a Waterfall model and ended up with an Evolutionary model

  3. Pressure Garment Subsystem Roadmap

    Science.gov (United States)

    Ross, Amy J.

    2010-01-01

    The Constellation program pressure garment subsystem (PGS) team has created a technical roadmap that communicates major technical questions and how and when the questions are being answered in support of major project milestones. The roadmap is a living document that guides the team priorities. The roadmap also communicates technical reactions to changes in project priorities and funding. This paper presents the roadmap and discusses specific roadmap elements in detail as representative examples to provide insight into the meaning and use of the roadmap.

  4. High pressure gas target

    Science.gov (United States)

    Gelbart, W.; Johnson, R. R.; Abeysekera, B.

    2012-12-01

    Compact, high pressure, high current gas target features all metal construction and semi-automatic window assembly change. The unique aspect of this target is the domed-shaped window. The Havar alloy window is electron beam welded to a metal ring, thus forming one, interchangeable assembly. The window assembly is sealed by knife-edges locked by a pneumatic toggle allowing a quick, in situ window change.

  5. INTRACRANIAL PRESSURE MONITORING TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Ida Bagus Adi Kayana

    2013-03-01

    Full Text Available Head injury is the most significant cause of increased morbidity and mortality. An estimated 1.4 million head injuries occur each year, with and more than 1.1 million come to the Emergency Unit. On each patient head injury, an increase in intracranial pressure (ICP related to poor outcomes and aggressive therapy to increased ICP can improve the outcomes. ICP monitoring is the most widely used because of the prevention and control of ICP as well as maintain the pressure increase perfusion of cerebral (Cerebral Perfusion Pressure/CPP is the basic purpose of handling head injury. There are two methods of monitoring ICP that is an invasive methods (directly and non-invasive techniques (indirectly. The method commonly used, namely intraventricular and intraparenkimal (microtransducer sensor because it is more accurate but keep attention to the existence of the risk of bleeding and infection resulting from installation. Monitoring of ICT can determine the actions that avoid further brain injury, which can be lethal and irreversibel.

  6. Pressure equalization system in PWR-fuel rods

    International Nuclear Information System (INIS)

    The pressure equalization system, developed on the basis of activated charcoal, is capable of reducing the internal pressure rise in fuel rods by adsorption of the fission gases. He-prepressure does not affect the system and Helium will not be adsorbed. Irradiation does not reduce the adsorption capacity of activated charcoal down to an unacceptable limit. Shaped activated charcoal is a suitable material which can be well defined and characterized. Feasible techniques of activating and assembling methods can be proposed. (orig.)

  7. Why and how acoustic emission in pressure vessel first hydrotest

    International Nuclear Information System (INIS)

    The main advantages obtained performing the Acoustic Emission (AE) examination during pressure vessel first hydrotest are presented. The characteristics and performance of the AE instrumentation to be used for a correct test are illustrated. The main criteria for AE source characterization (location, typical AE parameters and their correlation with pressure value), the calibration and test procedures are discussed. The ndt post-test examinations and laboratory specimen experiments are also outlined. Personnel qualification requirements are finally indicated. (Author)

  8. Characterization of atmospheric pressure plasmas for aerodynamic applications

    OpenAIRE

    Biganzoli,

    2014-01-01

    The use of plasmas in aerodynamics has become a recent topic of interest. In particular, over the last ten years, plasma actuation has received much attention as a promising active method for airflow control. Flow control consists of manipulating the properties of a generic moving fluid with the aim of achieving a desired change, but flow dynamics in proximity of a solid object is usually considered, being a consistent and significant issue in many engineering applications, such as engine, au...

  9. Performance characterization of solid oxide cells under high pressure

    DEFF Research Database (Denmark)

    Sun, Xiufu; Bonaccorso, Alfredo Damiano; Graves, Christopher R.;

    2014-01-01

    Solid oxide electrolysis cells (SOECs) offer a great potential for large scale conversion of renewable electrical energy into chemical energy via electrolysis of H2O and CO2 to produce syngas (H2 + CO). The produced syngas can be further catalytically converted into various gaseous or liquid...

  10. Pressure Drop in Cyclone Separator at High Pressure

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    For the design of pressurized circulating fluidized beds, experiments were conducted in a small cyclone with 120 mm in diameter and 300 mm in height at high pressures and at atmospheric temperatures. Influence of air leakage from the stand pipe into the cyclone was specially focused. A semi-empirical model was developed for the predic tion of the pressure drop of the cyclone separator at different operate pressures with the effect of air leakage and inlet solid loading. The operate pressure, air leakage and inlet solid loading act as significant roles in cyclone pressure drop. The pressure drop increases with the increasing of pressure and decreases with the increasing of the flow rate of air leakage from the standpipe and with the increasing of the inlet solid loading.

  11. HIGH PRESSURE COAL COMBUSTON KINETICS PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    Stefano Orsino

    2005-03-30

    As part of the U.S. Department of Energy (DoE) initiative to improve the efficiency of coal-fired power plants and reduce the pollution generated by these facilities, DOE has funded the High-Pressure Coal Combustion Kinetics (HPCCK) Projects. A series of laboratory experiments were conducted on selected pulverized coals at elevated pressures with the specific goals to provide new data for pressurized coal combustion that will help extend to high pressure and validate models for burnout, pollutant formation, and generate samples of solid combustion products for analyses to fill crucial gaps in knowledge of char morphology and fly ash formation. Two series of high-pressure coal combustion experiments were performed using SRI's pressurized radiant coal flow reactor. The first series of tests characterized the near burner flame zone (NBFZ). Three coals were tested, two high volatile bituminous (Pittsburgh No.8 and Illinois No.6), and one sub-bituminous (Powder River Basin), at pressures of 1, 2, and 3 MPa (10, 20, and 30 atm). The second series of experiments, which covered high-pressure burnout (HPBO) conditions, utilized a range of substantially longer combustion residence times to produce char burnout levels from 50% to 100%. The same three coals were tested at 1, 2, and 3 MPa, as well as at 0.2 MPa. Tests were also conducted on Pittsburgh No.8 coal in CO2 entrainment gas at 0.2, 1, and 2 MPa to begin establishing a database of experiments relevant to carbon sequestration techniques. The HPBO test series included use of an impactor-type particle sampler to measure the particle size distribution of fly ash produced under complete burnout conditions. The collected data have been interpreted with the help of CFD and detailed kinetics simulation to extend and validate devolatilization, char combustion and pollutant model at elevated pressure. A global NOX production sub-model has been proposed. The submodel reproduces the performance of the detailed chemical

  12. Measurement of Strong Shock Pressure

    Directory of Open Access Journals (Sweden)

    Hajime Takada

    1997-01-01

    Full Text Available This paper deals with measurement of a strong shock pressure like an imploding detonation of over 1 GPa which cannot be measured directly with currently available commercial pressure transducers. After the transfer functions of three kinds of materials were measured using a shock tube, Teflon was selected as a shock absorber. As an example of pressure beyond the limit of the pressure transducer, we tried to measure pressure at the center of an imploding detonation. From this measurement, we could estimate the pressure peak of about 1.7 GPa.

  13. Pressurized thermal shock (PTS)

    International Nuclear Information System (INIS)

    In the present work, a description of Thermal Shock in Pressurized conditions (PTS), and its influence in the treatment of the integrity of the pressure vessel (RPV) of a Pressurized Water Reactor (PWR) and/or of a Heavy water Pressurized water Reactor (PHWR) is made. Generally, the analysis of PTS involves a process of three stages: a-) Modeling with a System Code of relevant thermohydraulics transients in reference with the thermal shock; b-) The local distribution of temperatures in the downcomer and the heat transference coefficients from the RPV wall to the fluid, are determined; c-) The fracture mechanical analysis. These three stages are included in this work: Results with the thermohydraulics code Relap5/mod.3, are obtained, for a LOCA scenario in the hot leg of the cooling System of the Primary System of the CAN-I reactor. The method used in obtaining results is described. A study on the basis of lumped parameters of the local evolutions of the temperature of the flow is made, in the downcomer of the reactor pressure vessel. The purpose of this study is to determine how the intensification of the stress coefficient, varies in function of the emergency injected water during the thermohydraulic transients that take place under the imposed conditions in the postulated scene. Specially, it is considered a 50 cm2 break, located in the neighborhoods of the pressurized with the corresponding hot leg connection. This size is considered like the most critical. The method used to obtain the results is described. The fracture mechanical analysis is made. From the obtained results we confirmed that we have a simple tool of easy application in order to analyze phenomena of the type PTS in the postulated scenes by break in the cold and hot legs of the primary system. This methodology of calculus is completely independent of the used ones by the Nucleoelectrica Argentina S.A. (NASA) in the analysis of the PTS phenomena in the CAN-I. The results obtained with the adopted

  14. CMOS MEMS capacitive absolute pressure sensor

    International Nuclear Information System (INIS)

    This paper presents the design, fabrication and characterization of a capacitive pressure sensor using a commercial 0.18 µm CMOS (complementary metal–oxide–semiconductor) process and postprocess. The pressure sensor is capacitive and the structure is formed by an Al top electrode enclosed in a suspended SiO2 membrane, which acts as a movable electrode against a bottom or stationary Al electrode fixed on the SiO2 substrate. Both the movable and fixed electrodes form a variable parallel plate capacitor, whose capacitance varies with the applied pressure on the surface. In order to release the membranes the CMOS layers need to be applied postprocess and this mainly consists of four steps: (1) deposition and patterning of PECVD (plasma-enhanced chemical vapor deposition) oxide to protect CMOS pads and to open the pressure sensor top surface, (2) etching of the sacrificial layer to release the suspended membrane, (3) deposition of PECVD oxide to seal the etching holes and creating vacuum inside the gap, and finally (4) etching of the passivation oxide to open the pads and allow electrical connections. This sensor design and fabrication is suitable to obey the design rules of a CMOS foundry and since it only uses low-temperature processes, it allows monolithic integration with other types of CMOS compatible sensors and IC (integrated circuit) interface on a single chip. Experimental results showed that the pressure sensor has a highly linear sensitivity of 0.14 fF kPa−1 in the pressure range of 0–300 kPa. (paper)

  15. Classification of High Blood Pressure Persons Vs Normal Blood Pressure Persons Using Voice Analysis

    Directory of Open Access Journals (Sweden)

    Saloni

    2013-11-01

    Full Text Available The human voice is remarkable, complex and delicate. All parts of the body play some role in voice production and may be responsible for voice dysfunction. The larynx contains muscles that are surrounded by blood vessels connected to circulatory system. The pressure of blood in these vessels should be related with dynamic variation of vocal cord parameters. These parameters are directly related with acoustic properties of speech. Acoustic voice analysis can be used to characterize the pathological voices. This paper presents the classification of high blood pressure and normal with the aid of voice signal recorded from the patients. Various features have been extracted from the voice signal of healthy persons and persons suffering from high blood pressure. Simulation results show differences in the parameter values of healthy and pathological persons. Then an optimum feature vector is prepared and kmean classification algorithm was implemented for data classification. The 79% classification efficiency was obtained.

  16. CHARACTERIZATION, BIO-FORMULATION DEVELOPMENT AND SHELF-LIFE STUDIES OF LOCALLY ISOLATED BIO-FERTILIZER STRAINS

    Directory of Open Access Journals (Sweden)

    Vipin Kumar

    2014-03-01

    Full Text Available Nitrogen fixing, phosphate solubilizing and potash mobilizing bacterial strains were isolated from rhizosphere soil of agricultural land, the isolated bacterial strains were further characterized by a series of biochemical reactions and identified as genus Azotobacter, Bacillus and Pseudomonas respectively. A technology for their mass multiplication and their bio-formulation has been developed. Fly-ash was used as carrier materials for bio-formulation development of bio-fertilizer strains. Shelf-life studies of the bio-formulations were carried out during storage period. The selected isolates were found to be potent nitrogen fixer, phosphate solubilizers showing clear halo zone around their colonies and potash mobilizer showing mobilization of potassium on respective medium. A general decline in cfu count was noticed in fly-ash based bio-formulations. All the bio-formulations however, retained more than 108 cfu/g viable propagules up to 270 days. The present studies were shown encouraging results in respect to fly-ash as carrier materials for bio-fertilizer strains which are comparable to other commercially available carrier materials.

  17. Mechanisms of pressurization and insensitivity in TATB

    Science.gov (United States)

    Henson, Bryan; Smilowitz, Laura

    2015-06-01

    We have studied thermal ignition and subsequent internal deflagration in explosive formulations based on 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) with the goal of understanding the underlying mechanisms which combine to either enable or preclude the deflagration to detonation transition (DDT). We measure spatially resolved temperature, density change using new dynamic x-ray radiography techniques, and pressure inferred from observations of case deformation and direct measurement during ignition and burning in samples of variable initial density. We compare these observations with previous measurements on formulations of the more sensitive explosive octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). TATB deflagration is characterized by a measured ignition temperate approximately half that of HMX and very low pressures and rates of deflagration compared to HMX. Very stable and slow laminar internal burning is observed at lower densities as well as cracking, deconsolidation and a transition to faster deflagration rates under some conditions. We examine mechanism of pressure generation in the context of the combustion chemistry of TATB and discuss possible explanations of the lower observed rates and pressures when compared to HMX.

  18. Blood Pressure Matters: Keep Hypertension in Check

    Science.gov (United States)

    ... cuff, or an automatic device may measure the pressure. Blood pressure is given as 2 numbers. The first ... described above. High Blood Pressure NIHSeniorHealth: High Blood Pressure High Blood Pressure and Kidney Disease Heart and Vascular Diseases ...

  19. Questions and Answers about High Blood Pressure

    Science.gov (United States)

    ... Blood Pressure Page Content What is high blood pressure? Blood pressure is the force of blood against the ... do I know if I have high blood pressure? High blood pressure is often called "the silent killer" because ...

  20. VAPOR PRESSURES AND HEATS OF VAPORIZATION OF PRIMARY COAL TARS

    Energy Technology Data Exchange (ETDEWEB)

    Eric M. Suuberg; Vahur Oja

    1997-07-01

    This project had as its main focus the determination of vapor pressures of coal pyrolysis tars. It involved performing measurements of these vapor pressures and from them, developing vapor pressure correlations suitable for use in advanced pyrolysis models (those models which explicitly account for mass transport limitations). This report is divided into five main chapters. Each chapter is a relatively stand-alone section. Chapter A reviews the general nature of coal tars and gives a summary of existing vapor pressure correlations for coal tars and model compounds. Chapter B summarizes the main experimental approaches for coal tar preparation and characterization which have been used throughout the project. Chapter C is concerned with the selection of the model compounds for coal pyrolysis tars and reviews the data available to us on the vapor pressures of high boiling point aromatic compounds. This chapter also deals with the question of identifying factors that govern the vapor pressures of coal tar model materials and their mixtures. Chapter D covers the vapor pressures and heats of vaporization of primary cellulose tars. Chapter E discusses the results of the main focus of this study. In summary, this work provides improved understanding of the volatility of coal and cellulose pyrolysis tars. It has resulted in new experimentally verified vapor pressure correlations for use in pyrolysis models. Further research on this topic should aim at developing general vapor pressure correlations for all coal tars, based on their molecular weight together with certain specific chemical characteristics i.e. hydroxyl group content.

  1. Effect of pressure on arsenic diffusion in germanium

    International Nuclear Information System (INIS)

    We report preliminary results of a study of the activation volume for diffusion of arsenic in germanium. High-temperature high-pressure anneals were performed in a liquid argon pressure medium in a diamond anvil cell capable of reaching 5 GPa and 750 C,l which is externally heated for uniform and repeatable temperature profiles. Broadening of an ion-implanted arsenic profile was measured by Secondary Ion Mass Spectrometry. Hydrostatic pressure retards the diffusivity at 575 C, characterized by an activation volume that is +15% of the atomic volume of Ge. Implications for diffusion mechanisms are discussed

  2. Specific Blood Pressure Targets for Patients With Diabetic Nephropathy?

    Science.gov (United States)

    Grassi, Guido; Mancia, Giuseppe; Nilsson, Peter M

    2016-08-01

    Diabetic nephropathy represents a condition frequently detected in current clinical practice characterized by a very high cardiovascular risk profile. Blood pressure reduction via antihypertension drug treatment represents a therapeutic approach capable of exerting favorable effects on renal and cardiovascular outcomes. The purpose of this article is to review the current literature and results of key clinical trials pertaining to blood pressure goals of antihypertension treatment in these patients. The pros and cons of a less or a more intensive blood pressure goal in diabetic nephropathy will be discussed, with particular emphasis on the cardiovascular and renal effects of each therapeutic strategy. PMID:27440837

  3. Investigation of Methacrylic Acid at High Pressure Using Neutron Diffraction

    DEFF Research Database (Denmark)

    Marshall, William G.; Urquhart, Andrew; Oswald, Iain D. H.

    2015-01-01

    pressures. The first is observed at 0.39 GPa, where both phases were observed simultaneously and confirm our previous observations. This transition is followed by a second transition at 1.2 GPa to a new polymorph that is characterized for the first time. On increasing pressure, the diffraction pattern...... of phase III deteriorates significantly. On decompression phase III persists to 0.54 GPa before transformation to the ambient pressure phase. There is significant loss of signal after decompression, signifying that there has been a loss of material through polymerization. The orientation of the molecules...

  4. Detrended fluctuation analysis of a systolic blood pressure control loop

    Energy Technology Data Exchange (ETDEWEB)

    Galhardo, C E C; Penna, T J P; Argollo de Menezes, M [Instituto de Fisica, Universidade Federal Fluminense, Av. Litoranea, s/n, 24210-340, Niteroi, RJ (Brazil); Soares, P P S [Instituto Biomedico, Universidade Federal Fluminense, R. Prof. Hernani Melo n. 101, 24210-130, Niteroi, RJ (Brazil)], E-mail: marcio@mail.if.uff.br

    2009-10-15

    We use detrended fluctuation analysis (DFA) to study the dynamics of blood pressure oscillations and its feedback control in rats by analyzing systolic pressure time series before and after a surgical procedure that interrupts its control loop. We found, for each situation, a crossover between two scaling regions characterized by exponents that reflect the nature of the feedback control and its range of operation. In addition, we found evidence of adaptation in the dynamics of blood pressure regulation a few days after surgical disruption of its main feedback circuit. Based on the paradigm of antagonistic, bipartite (vagal and sympathetic) action of the central nerve system, we propose a simple model for pressure homeostasis as the balance between two nonlinear opposing forces, successfully reproducing the crossover observed in the DFA of actual pressure signals.

  5. Detrended Fluctuation Analysis of Systolic Blood Pressure Control Loop

    CERN Document Server

    Galhardo, C E C; de Menezes, M Argollo; Soares, P P S

    2009-01-01

    We use detrended fluctuation analysis (DFA) to study the dynamics of blood pressure oscillations and its feedback control in rats by analyzing systolic pressure time series before and after a surgical procedure that interrupts its control loop. We found, for each situation, a crossover between two scaling regions characterized by exponents that reflect the nature of the feedback control and its range of operation. In addition, we found evidences of adaptation in the dynamics of blood pressure regulation a few days after surgical disruption of its main feedback circuit. Based on the paradigm of antagonistic, bipartite (vagal and sympathetic) action of the central nerve system, we propose a simple model for pressure homeostasis as the balance between two nonlinear opposing forces, successfully reproducing the crossover observed in the DFA of actual pressure signals.

  6. Universal Non-thermal Pressure Fraction Profile in Galaxy Clusters

    CERN Document Server

    Nelson, Kaylea; Nagai, Daisuke

    2014-01-01

    Cosmological constraints from X-ray and microwave observations of galaxy clusters are subjected to systematic uncertainties. Non-thermal pressure support due to internal gas motions in galaxy clusters is one of the major sources of astrophysical uncertainties. Using a mass-limited sample of galaxy clusters from a high-resolution hydrodynamical cosmological simulation, we characterize the non-thermal pressure fraction profile and study its dependence on redshift, mass, and mass accretion rate. We find that the non-thermal pressure fraction profile is universal across redshift when galaxy cluster radii are defined with respect to the mean matter density of the universe instead of the commonly used critical density. We also find that the non-thermal pressure is predominantly radial, and the gas velocity anisotropy profile exhibits strong universality when galaxy cluster radii are defined with respect to the mean matter density of the universe. However, we find that the non-thermal pressure fraction is strongly d...

  7. Saltstone Osmotic Pressure

    International Nuclear Information System (INIS)

    Recent research into the moisture retention properties of saltstone suggest that osmotic pressure may play a potentially significant role in contaminant transport (Dixon et al., 2009 and Dixon, 2011). The Savannah River Remediation Closure and Disposal Assessments Group requested the Savannah River National Laboratory (SRNL) to conduct a literature search on osmotic potential as it relates to contaminant transport and to develop a conceptual model of saltstone that incorporates osmotic potential. This report presents the findings of the literature review and presents a conceptual model for saltstone that incorporates osmotic potential. The task was requested through Task Technical Request HLW-SSF-TTR-2013-0004. Simulated saltstone typically has very low permeability (Dixon et al. 2008) and pore water that contains a large concentration of dissolved salts (Flach and Smith 2013). Pore water in simulated saltstone has a high salt concentration relative to pore water in concrete and groundwater. This contrast in salt concentration can generate high osmotic pressures if simulated saltstone has the properties of a semipermeable membrane. Estimates of osmotic pressure using results from the analysis of pore water collected from simulated saltstone show that an osmotic pressure up to 2790 psig could be generated within the saltstone. Most semi-permeable materials are non-ideal and have an osmotic efficiency 3, KNO3, Na3PO4x12H 2O, and K3PO4 when exposed to a dilute solution. Typically hydraulic head is considered the only driving force for groundwater in groundwater models. If a low permeability material containing a concentrated salt solution is present in the hydrogeologic sequence large osmotic pressures may develop and lead to misinterpretation of groundwater flow and solute transport. The osmotic pressure in the semi-permeable material can significantly impact groundwater flow in the vicinity of the semi-permeable material. One possible outcome is that groundwater

  8. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... above. Confirming High Blood Pressure A blood pressure test is easy and painless and can be done ... provider’s office or clinic. To prepare for the test: Don’t drink coffee or smoke cigarettes for ...

  9. High blood pressure and diet

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007483.htm High blood pressure and diet To use the sharing features on ... diet is a proven way to help control high blood pressure . These changes can also help you lose weight ...

  10. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... track blood pressure readings over a period of time, the health care provider may ask you to ... the office on different days and at different times to take your blood pressure. The health care ...

  11. High pressure diffraction at ISIS

    International Nuclear Information System (INIS)

    The development of the high pressure diffraction programme at ISIS is reviewed. Along with general accounts of the technique and the pressure cells used, examples of science carried out in this field are given. (author)

  12. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... visit the health care provider, he or she should tell you what your blood pressure numbers are; if he or she does not, you should ask for your readings. Blood Pressure Severity and ...

  13. Mediator-Generated Pressure Tactics

    Science.gov (United States)

    Byrnes, Joseph F.

    1978-01-01

    Two examples of bluff pressures (as opposed to real pressures) used by mediators to effect contract settlements are presented, along with advice to negotiators on avoiding or minimizing such tactics. (Author/IRT)

  14. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... Clinical Trials What Are Clinical Trials? Children & Clinical Studies NHLBI ... providers diagnose high blood pressure when blood pressure readings are consistently 140/90 mmHg or above. Confirming High Blood ...

  15. Diagnosis of High Blood Pressure

    Science.gov (United States)

    ... Clinical Trials What Are Clinical Trials? Children & Clinical Studies NHLBI ... providers diagnose high blood pressure when blood pressure readings are consistently 140/90 mmHg or above. Confirming High Blood ...

  16. High Blood Pressure in Pregnancy

    Science.gov (United States)

    ... of the baby. Controlling your blood pressure during pregnancy and getting regular prenatal care are important for ... your baby. Treatments for high blood pressure in pregnancy may include close monitoring of the baby, lifestyle ...

  17. Shielding Idiosyncrasy from Isomorphic Pressures

    DEFF Research Database (Denmark)

    Alvarez, José Luis; Mazza, Carmelo; Strandgaard Pedersen, Jesper;

    2003-01-01

    Moretti (Italy) and Lars vonTrier (Denmark). We argue that in a cinemafield, artistic pressures for distinctivenessalong with business pressures for profitsdrive filmmakers' quest for optimaldistinctiveness. This quest seeks bothexclusive, unique style and inclusive,audience-appealing artwork with...

  18. Genes That Influence Blood Pressure

    Science.gov (United States)

    ... Research Matters NIH Research Matters September 26, 2011 Genes that Influence Blood Pressure In one of the ... 16 previously unknown variations. Six were found in genes already suspected of regulating blood pressure. The remaining ...

  19. INTRACRANIAL PRESSURE MONITORING

    Directory of Open Access Journals (Sweden)

    Retno Widiyanthi

    2013-07-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE Intracranial pressure is total of pressure that is produced by brain, blood, and cerebrospinal fluid/CSF in the tight cranial space. As a respon to intracranial pressure increasing, compensation begin by movement of CSF from ventricle to cerebral subarachnoidal space, and increase the absorption of CSF. Increasing of ICP usually caused by increasing of brain volume (cerebral oedem, blood (intracranial bleeding, space occupying lesion, or CSF (hidrocephalus. Indication in ICP monitoring can be seen from : neurological criteria, abnormal CT-scan result when admission, normal CT-scan result, but had more two risk factors. According to the procedure that must be done, there are two methods in ICP monitoring: invasive ICP monitoring methodes and non-invasive measuring method. Increasing of ICP will decrease the compliance of brain, pulsation of artery more clearly, and the component of vein is lost. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

  20. Unibody Composite Pressurized Structure

    Science.gov (United States)

    Rufer, Markus; Conger, Robert; Bauer, Thomas; Newman, John

    2013-01-01

    An integrated, generic unibody composite pressurized structure (UCPS) combined with a positive expulsion device (PED), consisting of an elastomeric bladder for monopropellant hydrazine, has been quasi-standardized for spacecraft use. The combination functions as an all-composite, non-metallic, propellant tank with bladder. The integrated UCPS combines several previous innovations - specifically, the linerless, all-composite cryogenic tank technology; all-composite boss; resin formulation; and integrated stringer system. The innovation combines the UCPS with an integrated propellant management device (PMD), the PED or bladder, to create an entirely unique system for in-space use. The UCPS is a pressure vessel that incorporates skirts, stringers, and other structures so that it is both an in-space hydrazine tank, and also a structural support system for a spacecraft in a single, all-composite unit. This innovation builds on the progress in the development of a previous SBIR (Small Business Innovation Research) Phase I with Glenn Research Center and an SBIR III with Johnson Space Center that included the fabrication of two 42-in. (˜107-cm) diameter all-composite cryogenic (LOX and liquid methane) UCPS test tanks for a lunar lander. This Phase II provides hydra zine compatibility testing of the elastomeric bladder, a see-through PED to validate the expulsion process and model, and a complete UCPS-based PED with stringers and skirts that will be used to conduct initial qualification and expulsion tests. This extends the UCPS technology to include hydrazine-based, in-space pro - pulsion applications and can also be used for electric propulsion. This innovation creates a system that, in comparison to the traditional approach, is lower in weight, cost, volume, and production time; is stronger; and is capable of much higher pressures. It also has fewer failure modes, and is applicable to both chemical and electric propulsion systems.

  1. Barotrauma: Tooth Under Pressure.

    Science.gov (United States)

    Kumar, Satheesh; Kumar, Preeti Satheesh; John, Jins; Patel, Ruchi

    2015-11-01

    With the growing number of air passengers, flight attendants, leisure pilots, as well as military and airline pilots, dentists may encounter physiological and pathological phenomena precipitated by high altitude. With the introduction of the self-contained breathing apparatus (SCUBA), many of these manifestations caused by changes in atmospheric pressure were reported in association with diving as well. Limited literature exists on this subject. Hence, this article aims to review literature concerning the classification, etiology and manifestations of barodontalgia, as well as important clinical considerations for its management. PMID:26697664

  2. Pressure pain sensitivity

    DEFF Research Database (Denmark)

    Bergmann, Natasha; Ballegaard, Søren; Holmager, Pernille;

    2013-01-01

    induce hyperalgesia.The aim of the present study was to evaluate hyperalgesia by pressure pain sensitivity (PPS) in patients with IHD, and compare PPS to questionnaires measuring depressive symptoms, reduced psychological wellbeing, and QOL as markers of stress. Design. A cross-sectional study of 361...... subjects with IHD. Methods. PPS was measured on the sternum, and compared to the questionnaires: Clinical stress symptoms score (CSS), Major Depression Inventory (MDI), WHO-5 Wellbeing Index, and SF-36 QOL score. Results. PPS correlated to CSS (r = 0.20, p <0.001), MDI (r = 0.14, p = 0.02), SF-36 mental...

  3. Saltstone Osmotic Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, Ralph L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Dixon, Kenneth L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRN

    2013-09-23

    Recent research into the moisture retention properties of saltstone suggest that osmotic pressure may play a potentially significant role in contaminant transport (Dixon et al., 2009 and Dixon, 2011). The Savannah River Remediation Closure and Disposal Assessments Group requested the Savannah River National Laboratory (SRNL) to conduct a literature search on osmotic potential as it relates to contaminant transport and to develop a conceptual model of saltstone that incorporates osmotic potential. This report presents the findings of the literature review and presents a conceptual model for saltstone that incorporates osmotic potential. The task was requested through Task Technical Request HLW-SSF-TTR- 2013-0004.

  4. Investigations into low pressure methanol synthesis

    DEFF Research Database (Denmark)

    Sharafutdinov, Irek

    The central topic of this work has been synthesis, characterization and optimization of novel Ni-Ga based catalysts for hydrogenation of CO2 to methanol. The overall goal was to search for materials that could be used as a low temperature (and low pressure) methanol synthesis catalyst. This is...... required for small scale delocalized methanol production sites, where installation of energy demanding compression units should be avoided. The work was triggered by DFT calculations, which showed that certain bimetallic systems are active towards methanol synthesis from CO2 and H2 at ambient pressure...... containing 5:3 molar ratio of Ni:Ga, the intrinsic activity (methanol production rate per active surface area) is comparable to that of highly optimised Cu/ZnO/Al2O3. Formation of the catalyst was investigated with the aid of in-situ XRD and in-situ XAS techniques. The mechanism of alloying was proposed. It...

  5. Murata - A Pressure Sensor Based Blood Pressure : Preliminary Reliability Study

    OpenAIRE

    Nummelin, Elina

    2015-01-01

    The purpose of the study was to determine the reliability of a blood pressure sensor developed by Murata as a blood pressure monitoring tool compared to an automatic blood pressure monitor, Omron M6. Blood pressure is one of the principal vital signs and is utilized for monitoring both short-term and long-term health of the cardiovascular system and thereby the health of the patient. Therefore there is a need for a non-invasive blood pressure monitor for accurate, continuous and comfortab...

  6. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... Diagnosis of High Blood Pressure For most patients, health care providers diagnose high blood pressure when blood pressure ... and painless and can be done in a health care provider’s office or clinic. To prepare for the ...

  7. Gas Pressure-Drop Experiment

    Science.gov (United States)

    Luyben, William L.; Tuzla, Kemal

    2010-01-01

    Most chemical engineering undergraduate laboratories have fluid mechanics experiments in which pressure drops through pipes are measured over a range of Reynolds numbers. The standard fluid is liquid water, which is essentially incompressible. Since density is constant, pressure drop does not depend on the pressure in the pipe. In addition, flow…

  8. Instrument measures dynamic pressure fluctuations

    Science.gov (United States)

    Coats, J. W.; Penko, P. E.; Reshotko, M.

    1977-01-01

    Pressure probe instrument, incorporating "infinite line" principle, can be used to remotely measure dynamic pressure fluctuations in hot high-pressure environemnts too severe for sensors. System is designed and can be utilized for measurements in core of operating turbofan engine.

  9. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... page from the NHLBI on Twitter. Diagnosis of High Blood Pressure For most patients, health care providers diagnose high ... are consistently 140/90 mmHg or above. Confirming High Blood Pressure A blood pressure test is easy and painless ...

  10. Living with High Blood Pressure

    Science.gov (United States)

    ... from the NHLBI on Twitter. Living With High Blood Pressure If you have high blood pressure, the best thing to do is to talk ... care provider and take steps to control your blood pressure by making healthy lifestyle changes and taking medications, ...

  11. Pressure Safety: Advanced Live 11459

    Energy Technology Data Exchange (ETDEWEB)

    Glass, George [Los Alamos National Laboratory

    2016-03-02

    Many Los Alamos National Laboratory (LANL) operations use pressure equipment and systems. Failure to follow proper procedures when designing or operating pressure systems can result in injuries to personnel and damage to equipment and/or the environment. This manual presents an overview of the requirements and recommendations that address the safe design and operation of pressure systems at LANL.

  12. Dual rate pressure relief valve

    Science.gov (United States)

    Steeneken, J.

    1968-01-01

    Pressure relief valve vents at a slow bleed rate at one pressure level and at a higher bleed rate at a higher pressure level. The value housing contains a sleeve, inlet port, outlet port, an orifice, a ball and seat arrangement, and a belleville spring diaphragm.

  13. Photonic crystal fiber pressure sensor

    Science.gov (United States)

    Fávero, F. C.; Quintero, S. M. M.; Silva, V. V.; Martelli, C.; Braga, Arthur M. B.; Carvalho, Isabel C. S.; Llerena, Roberth W. A.

    2009-10-01

    A high sensitivity optical fiber pressure sensor based on a modal interferometer with high birefringence photonic fiber is proposed and demonstrated. The sensor dependence with hydrostatic pressure is evaluated both numerically and experimentally. The measured pressure sensitivity at room temperature is found to be 3.36 nmMPa-1.

  14. The Myth of Peer Pressure.

    Science.gov (United States)

    Ungar, Michael T.

    2000-01-01

    The construct of peer pressure was examined as part of a qualitative study of the determinants of mental health for 41 high-risk adolescents. While the concept of peer pressure enables adults to explain youths' troubling behaviors, content analysis of the participants' accounts of their lives reveals peer pressure to be a myth. (Author/MKA)

  15. Pressure transients in pipeline systems

    DEFF Research Database (Denmark)

    Voigt, Kristian

    1998-01-01

    This text is to give an overview of the necessary background to do investigation of pressure transients via simulations. It will describe briefly the Method of Characteristics which is the defacto standard for simulating pressure transients. Much of the text has been adopted from the book Pressur...

  16. Experimental research on pressure loss of rotary pressure exchanger

    Science.gov (United States)

    Jiao, L.; Shi, Y.; Liu, Z. C.; Li, L.; Feng, Z. M.; Zhao, C. F.; Wei, Y.

    2016-05-01

    In order to research the phenomenon ‘Pressure Loss’ of Rotary Pressure Exchanger when it worked in a certain working condition, such as pressure and flow, two different series of experiments were performed respectively in the same experimental apparatus. One is to set pressure as constant when flow is changeable, the other one is to set flow as constant when pressure is changeable. Then, the curves and tables depicting the relationship between the pressure loss rate and working conditions were illustrated. Results from the curves and tables show that flow and pressure has an impact on pressure loss, and the relationship present some of regularity. According to the regularity, an empirical formula which can be used to approximately predict the magnitude of pressure loss for subsequent engineering application was provided by regression analysis on the basis of experimental data. Meanwhile, a 3-Dimensional geometric model of passageway in rotary pressure exchanger were built to verify the accuracy, making a steady calculation on pressure field by Fluent. At last, the feasibility was verified in a field application in a desalination factory.

  17. Pressure polymerization of polyester

    Science.gov (United States)

    Maurer, Charles J.; Shaw, Gordon; Smith, Vicky S.; Buelow, Steven J.; Tumas, William; Contreras, Veronica; Martinez, Ronald J.

    2000-08-29

    A process is disclosed for the preparation of a polyester polymer or polyester copolymer under superatmospheric pressure conditions in a pipe or tubular reaction under turbannular flow conditions. Reaction material having a glycol equivalents to carboxylic acid equivalents mole ratio of from 1.0:1 to 1.2:1, together with a superatmospheric dense gaseous medium are fed co-currently to the reactor. Dicarboxylic acid and/or diol raw materials may be injected into any of the reaction zones in the process during operation to achieve the overall desired mole ratio balance. The process operates at temperatures of from about 220.degree. C. to about 320.degree. C., with turbannular flow achieved before the polymer product and gas exit the reactor process. The pressure in the reaction zones can be in the range from 15 psia to 2500 psia. A polymer product having a DP of a greater than 40, more preferably at least about 70, is achieved by the transfer of water from the reacting material polymer melt to the gaseous medium in the reactor.

  18. Studies on pressure-gain combustion engines

    Science.gov (United States)

    Matsutomi, Yu

    Various aspects of the pressure-gain combustion engine are investigated analytically and experimentally in the current study. A lumped parameter model is developed to characterize the operation of a valveless pulse detonation engine. The model identified the function of flame quenching process through gas dynamic process. By adjusting fuel manifold pressure and geometries, the duration of the air buffer can be effectively varied. The parametric study with the lumped parameter model has shown that engine frequency of up to approximately 15 Hz is attainable. However, requirements for upstream air pressure increases significantly with higher engine frequency. The higher pressure requirement indicates pressure loss in the system and lower overall engine performance. The loss of performance due to the pressure loss is a critical issue for the integrated pressure-gain combustors. Two types of transitional methods are examined using entropy-based models. An accumulator based transition has obvious loss due to sudden area expansion, but it can be minimized by utilizing the gas dynamics in the combustion tube. An ejector type transition has potential to achieve performance beyond the limit specified by a single flow path Humphrey cycle. The performance of an ejector was discussed in terms of apparent entropy and mixed flow entropy. Through an ideal ejector, the apparent part of entropy increases due to the reduction in flow unsteadiness, but entropy of the mixed flow remains constant. The method is applied to a CFD simulation with a simple manifold for qualitative evaluation. The operation of the wave rotor constant volume combustion rig is experimentally examined. The rig has shown versatility of operation for wide range of conditions. Large pressure rise in the rotor channel and in a section of the exhaust duct are observed even with relatively large leakage gaps on the rotor. The simplified analysis indicated that inconsistent combustion is likely due to insufficient

  19. Transducer characterization

    International Nuclear Information System (INIS)

    For inservice inspection transducer characterization can be an important item if one wants to compare ultrasonic examination data obtained at different times (fingerprint). It is possible that the transducers used during previous examinations are lost or will become defect. In such a case it is most useful if one can check the characteristics of the replacement transducers. Some time ago an elegant characterization method was developed by the EURATOM Joint Research Centre of Ispra based on liquid crystals. This method is now under development at Neratoom and the results so far indicate that a robust characterization rig can be built at a reasonable price

  20. Clinical management of pressure ulcers.

    Science.gov (United States)

    Thomas, David R

    2013-05-01

    Pressure ulcers are chronic and difficult to heal. Pressure-reducing devices are clearly superior to a standard hospital mattress in preventing pressure ulcers, but only limited evidence and clinical intuition supports pressure-reducing devices in improving the healing rate of pressure ulcers. Local wound treatment should aim at maintaining a moist wound environment. The choice of a particular dressing depends on wound characteristics, such as the amount of exudate, dead space, or wound location. Nutritional status should be addressed as a process of good care. Debridement may improve time to a clean wound bed, but no clearly superior approach has been demonstrated. PMID:23571035

  1. High Temperature Electrolysis Pressurized Experiment Design, Operation, and Results

    Energy Technology Data Exchange (ETDEWEB)

    J.E. O' Brien; X. Zhang; G.K. Housley; K. DeWall; L. Moore-McAteer

    2012-09-01

    A new facility has been developed at the Idaho National Laboratory for pressurized testing of solid oxide electrolysis stacks. Pressurized operation is envisioned for large-scale hydrogen production plants, yielding higher overall efficiencies when the hydrogen product is to be delivered at elevated pressure for tank storage or pipelines. Pressurized operation also supports higher mass flow rates of the process gases with smaller components. The test stand can accommodate planar cells with dimensions up to 8.5 cm x 8.5 cm and stacks of up to 25 cells. It is also suitable for testing other cell and stack geometries including tubular cells. The pressure boundary for these tests is a water-cooled spool-piece pressure vessel designed for operation up to 5 MPa. Pressurized operation of a ten-cell internally manifolded solid oxide electrolysis stack has been successfully demonstrated up 1.5 MPa. The stack is internally manifolded and operates in cross-flow with an inverted-U flow pattern. Feed-throughs for gas inlets/outlets, power, and instrumentation are all located in the bottom flange. The entire spool piece, with the exception of the bottom flange, can be lifted to allow access to the internal furnace and test fixture. Lifting is accomplished with a motorized threaded drive mechanism attached to a rigid structural frame. Stack mechanical compression is accomplished using springs that are located inside of the pressure boundary, but outside of the hot zone. Initial stack heatup and performance characterization occurs at ambient pressure followed by lowering and sealing of the pressure vessel and subsequent pressurization. Pressure equalization between the anode and cathode sides of the cells and the stack surroundings is ensured by combining all of the process gases downstream of the stack. Steady pressure is maintained by means of a backpressure regulator and a digital pressure controller. A full description of the pressurized test apparatus is provided in this

  2. ORANGE JUICE AND BLOOD PRESSURE

    Directory of Open Access Journals (Sweden)

    M. F. VALIM

    2009-01-01

    Full Text Available

    Blood pressure is the force of blood against artery walls. It is measured in millimeters of mercury (mm Hg and recorded as two numbers: systolic pressure (as the heart contracts over diastolic pressure (as the heart relaxes between beats. High blood pressure (hypertension is defined as chronically elevated high blood pressure, with systolic blood pressure (SBP of 140 mm Hg or greater, and diastolic blood pressure (DBP of 90 mm Hg or greater. High blood pressure (HBP, smoking, abnormal blood lipid levels, obesity and diabetes are risk factors for coronary heart disease, the leading cause of death in the US. Lifestyle modifications such as engaging in regular physical activity, quitting smoking and eating a healthy diet (limiting intake of saturated fat and sodium and increasing consumption of fiber, fruits and vegetables are advocated for the prevention, treatment, and control of HBP. As multiple factors influence blood pressure, the effects of each factor are typically modest, particularly in normotensive subjects, yet the combined effects can be substantial. Nutrition plays an important role in influencing blood pressure. Orange juice should be included as part of any low sodium diet and/or any blood pressure reducing eating plan, as it is sodium free, fat-free and can help meet recommended levels of potassium intake that may contribute to lower BP.

  3. BWR zero pressure containment

    International Nuclear Information System (INIS)

    This patent describes the operation of a nuclear reactor system, the system including a containment defining a drywall space wherein a nuclear reactor is disposed, there being a suppression pool in the containment with the suppression pool having a wetwell space above a level of the pool to which an non-condensable gases entering the suppression pool can vent. It comprises: continuously exhausting the wetwell space to remove gas mixture therefrom while admitting inflow of air from an atmospheric source thereof to the wetwell during normal operation by blocking off the inflow during a loss-of-coolant-accident whenever a pressure in the wetwell space is above a predetermined value, and subjecting the gas subsequent to its removal from the wetwell to a treatment operation to separate any particulate material entrained therein from the gas mixture

  4. Effects of pressure waves

    Science.gov (United States)

    1977-01-01

    Two parameters, side on overpressure and side on impulse loads, and their application to the determination of structural damage to buildings and vehicles in the vicinity of an explosion are investigated. Special consideration was given to what constitutes damage and what level of damage is acceptable. Solutions were sorted through the examination of glass breakage, curve fit to bomb damage, overturning of marginal structures (buses, trucks, mobile homes) subject to toppling, and initiation of yielding in either beam or plate structural components. Three different empirical pressure versus impulse diagrams were presented - the first is for minor structural damage involving wrenched joints and partitions, the second is for major damage structural damage with load bearing members at least partially destroyed, and the third is for 50% to 75% of the building demolished. General guidelines were obtained from the results when the accurate structural details are unknown.

  5. From Pressures to Impacts

    DEFF Research Database (Denmark)

    Hauschild, Michael Zwicky

    2006-01-01

    Life cycle assessment (LCA) has been developed as a tool for assessment of the environmental impacts which are caused by the pressures from products or systems, viewed in a life cycle perspective, i.e. covering all stages of the life cycle of the product or system from the extraction of raw...... materials over manufacture or construction through use to disposal or decommissioning and recycling. It is a holistic tool in the sense that it models all relevant environmental impacts from the global (like climate change and ozone depletion) to the local (like land use) and also the loss of resources. The...... is defined, Inventory analysis where data for the physical flows to and from all processes in the life cycle is collected and related to the functional unit, Impact assessment, where the physical flows are translated into impacts on the environment and resource base, and Interpretation where the...

  6. Pressure vessel design manual

    Energy Technology Data Exchange (ETDEWEB)

    Moss, D.R.

    1987-01-01

    The first section of the book covers types of loadings, failures, and stress theories, and how they apply to pressure vessels. The book delineates the procedures for designing typical components as well as those for designing large openings in cylindrical shells, ring girders, davits, platforms, bins and elevated tanks. The techniques for designing conical transitions, cone-cylinder intersections, intermediate heads, flat heads, and spherically dished covers are also described. The book covers the design of vessel supports subject to wind and seismic loads and one section is devoted to the five major ways of analyzing loads on shells and heads. Each procedure is detailed enough to size all welds, bolts, and plate thicknesses and to determine actual stresses.

  7. Effects of shifting time on pressure impact in hydraulic systems

    Institute of Scientific and Technical Information of China (English)

    ZHU Zhen-cai; CHEN Guo-an

    2005-01-01

    The limitations in existing measures for absorbing pressure impact in hydraulic systems were summarized in this paper. Based on the forming principle of the oil in a hydrostatic closed pressure chamber, the underlying reasons of the pressure impact were analyzed theoretically, the intrinsic laws that the extent of the pressure impact in hydraulic oil lines are affected by some factors, such as oil elastic modulus, oil line's geometrical volume, and changing rate of oil volume versus time etc, were discussed. Experimental investigations into pressure impact in all pressure chambers because of shifting were conducted under different working conditions by employing a special experimental system. The effects of shifting time on pressure impact were studied. A new concept with universal meaning, i.e. optimal shifting time, and its characterizing parameter and the methods of shifting at optimal shifting time were also proposed. The results show that shifting time lag △t is of rationality and maneuverablility. The higher the working pressure, the shorter the shifting time.

  8. Detecting deterministic nature of pressure measurements from a turbulent combustor

    Science.gov (United States)

    Tony, J.; Gopalakrishnan, E. A.; Sreelekha, E.; Sujith, R. I.

    2015-12-01

    Identifying nonlinear structures in a time series, acquired from real-world systems, is essential to characterize the dynamics of the system under study. A single time series alone might be available in most experimental situations. In addition to this, conventional techniques such as power spectral analysis might not be sufficient to characterize a time series if it is acquired from a complex system such as a thermoacoustic system. In this study, we analyze the unsteady pressure signal acquired from a turbulent combustor with bluff-body and swirler as flame holding devices. The fractal features in the unsteady pressure signal are identified using the singularity spectrum. Further, we employ surrogate methods, with translational error and permutation entropy as discriminating statistics, to test for determinism visible in the observed time series. In addition to this, permutation spectrum test could prove to be a robust technique to characterize the dynamical nature of the pressure time series acquired from experiments. Further, measures such as correlation dimension and correlation entropy are adopted to qualitatively detect noise contamination in the pressure measurements acquired during the state of combustion noise. These ensemble of measures is necessary to identify the features of a time series acquired from a system as complex as a turbulent combustor. Using these measures, we show that the pressure fluctuations during combustion noise has the features of a high-dimensional chaotic data contaminated with white and colored noise.

  9. Estimation of vapour pressure and partial pressure of subliming compounds by low-pressure thermogravimetry

    Indian Academy of Sciences (India)

    G V Kunte; Ujwala Ail; P K Ajikumar; A K Tyagi; S A Shivashankar; A M Umarji

    2011-12-01

    A method for the estimation of vapour pressure and partial pressure of subliming compounds under reduced pressure, using rising temperature thermogravimetry, is described in this paper. The method is based on our recently developed procedure to estimate the vapour pressure from ambient pressure thermogravimetric data using Langmuir equation. Using benzoic acid as the calibration standard, vapour pressure–temperature curves are calculated at 80, 160 and 1000 mbar for salicylic acid and vanadyl bis-2,4-pentanedionate, a precursor used for chemical vapour deposition of vanadium oxides. Using a modification of the Langmuir equation, the partial pressure of these materials at different total pressures is also determined as a function of temperature. Such data can be useful for the deposition of multi-metal oxide thin films or doped thin films by chemical vapour deposition (CVD).

  10. Euglycemic clamp insulin sensitivity and longitudinal systolic blood pressure

    DEFF Research Database (Denmark)

    Petrie, John R; Malik, Muhammad Omar; Balkau, Beverley;

    2013-01-01

    Insulin resistance may be an independent risk factor for the development of hypertension, but change in blood pressure (BP) over time has not been adequately studied in healthy individuals fully characterized for insulin sensitivity. In the Relationship between Insulin Sensitivity and...

  11. Pressurized solvent extraction of pure food grade starch

    Science.gov (United States)

    A commercial pressurized solvent extractor was used to remove lipid and non-lipid material from cornstarch using n-propanol/water and ethanol/water mixtures. Yields and chemical composition of the extract fractions were determined. Cornstarch samples were characterized using pasting properties and...

  12. SOI based integrated on-chip photonic pressure sensor

    NARCIS (Netherlands)

    Chakkalakkal Abdulla, S.M.C.; Harmsma, P.J.; Nieuwland, R.A.; Pozo Torres, J.M.; Lemmen, M.H.J.; Sadeghian Marnani, H.; Berg, J.H. van den; Bodis, P.

    2012-01-01

    A compact, mass producible Silicon On Insulator (SOI) based pressure sensor consisting of a folded Micro Ring Resonator (MRR) on a circular diaphragm is successfully designed, fabricated and characterized [1-3]. The MRR is designed to be single mode for TE polarized light at 1550 nm. The folded MRR

  13. Evaluation of catastrophic failure risk in pressure vessels

    International Nuclear Information System (INIS)

    Within the Nordic countries a four-year research programme in the area of elastic-plastic fracture mechanics was initiated in 1985. Seven laboratories from Denmark, Finland, Norway and Sweden are participating in the programme. The main technical objective of the programme is to clarify how catastrophic fracture can be prevented in pressure vessels and piping by using the leak-before-break concept. The major experimental effort of the programme is destructive pressurization of a large size pressure vessel up to rupture. The vessel has dimensions similar to a nuclear reactor pressure vessel and it has been in operation for 20 years in a Finnish oil refinery plant. The materials characterization of the vessel has been partially carried out within an extensive Nordic round-robin programme. Two pressure tests have been carried out. In both tests an artificial sharp axial surface flaw was made on the inner wall of the vessel. The experimental details of the last test including repair welding of the vessel, flaw prepration, instrumentation and material characterization are described in this report. The fracture behaviour as well as experimental results are reported. The failure pressure is compared to estimates of the analytical pre-test calculations

  14. Multilayer Composite Pressure Vessels

    Science.gov (United States)

    DeLay, Tom

    2005-01-01

    A method has been devised to enable the fabrication of lightweight pressure vessels from multilayer composite materials. This method is related to, but not the same as, the method described in gMaking a Metal- Lined Composite-Overwrapped Pressure Vessel h (MFS-31814), NASA Tech Briefs, Vol. 29, No. 3 (March 2005), page 59. The method is flexible in that it poses no major impediment to changes in tank design and is applicable to a wide range of tank sizes. The figure depicts a finished tank fabricated by this method, showing layers added at various stages of the fabrication process. In the first step of the process, a mandrel that defines the size and shape of the interior of the tank is machined from a polyurethane foam or other suitable lightweight tooling material. The mandrel is outfitted with metallic end fittings on a shaft. Each end fitting includes an outer flange that has a small step to accommodate a thin layer of graphite/epoxy or other suitable composite material. The outer surface of the mandrel (but not the fittings) is covered with a suitable release material. The composite material is filament- wound so as to cover the entire surface of the mandrel from the step on one end fitting to the step on the other end fitting. The composite material is then cured in place. The entire workpiece is cut in half in a plane perpendicular to the axis of symmetry at its mid-length point, yielding two composite-material half shells, each containing half of the foam mandrel. The halves of the mandrel are removed from within the composite shells, then the shells are reassembled and bonded together with a belly band of cured composite material. The resulting composite shell becomes a mandrel for the subsequent steps of the fabrication process and remains inside the final tank. The outer surface of the composite shell is covered with a layer of material designed to be impermeable by the pressurized fluid to be contained in the tank. A second step on the outer flange of

  15. Steam Oxidation at High Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, Gordon R. [NETL; Carney, Casey [URS

    2013-07-19

    A first high pressure test was completed: 293 hr at 267 bar and 670{degrees}C; A parallel 1 bar test was done for comparison; Mass gains were higher for all alloys at 267 bar than at 1 bar; Longer term exposures, over a range of temperatures and pressures, are planned to provide information as to the commercial implications of pressure effects; The planned tests are at a higher combination of temperatures and pressures than in the existing literature. A comparison was made with longer-term literature data: The short term exposures are largely consistent with the longer-term corrosion literature; Ferritic steels--no consistent pressure effect; Austenitic steels--fine grain alloys less able to maintain protective chromia scale as pressure increases; Ni-base alloys--more mass gains above 105 bar than below. Not based on many data points.

  16. High temperature and pressure electrochemical test station

    Science.gov (United States)

    Chatzichristodoulou, C.; Allebrod, F.; Mogensen, M.

    2013-05-01

    An electrochemical test station capable of operating at pressures up to 100 bars and temperatures up to 400 °C has been established. It enables control of the partial pressures and mass flow of O2, N2, H2, CO2, and H2O in a single or dual environment arrangement, measurements with highly corrosive media, as well as localized sampling of gas evolved at the electrodes for gas analysis. A number of safety and engineering design challenges have been addressed. Furthermore, we present a series of electrochemical cell holders that have been constructed in order to accommodate different types of cells and facilitate different types of electrochemical measurements. Selected examples of materials and electrochemical cells examined in the test station are provided, ranging from the evaluation of the ionic conductivity of liquid electrolytic solutions immobilized in mesoporous ceramic structures, to the electrochemical characterization of high temperature and pressure alkaline electrolysis cells and the use of pseudo-reference electrodes for the separation of each electrode contribution. A future perspective of various electrochemical processes and devices that can be developed with the use of the established test station is provided.

  17. Pressure sensors for petroleum wells

    International Nuclear Information System (INIS)

    A patent is claimed for a pressure sensor to be used in petroleum wells. Measurements can be performed under extreme temperature and pressure conditions. The system consists of a cell, containing an extensometric circuit, placed in a container and in contact with the pressure to be measured. The cell is formed by two sapphire half-shells. Their crystallographic orientation is chosen in order to obtain isotropy of stresses. The sensor is nearly independent from temperature fluctuations

  18. Do professionals choke under pressure?

    OpenAIRE

    Dohmen, Thomas

    2005-01-01

    High rewards or the threat of severe punishment do not only provide incentives to exert high levels of effort but also create pressure. Such pressure can cause paradoxical performance effects, namely performance decrements despite strong incentives and high motivation. By analyzing the performance of professional football players on a well-defined task, namely to score on a penalty kick, the paper provides empirical evidence for the existence of such detrimental incentive effects. Two pressur...

  19. Neutron scattering at high pressure

    OpenAIRE

    Mcwhan, D.B.

    1984-01-01

    The techniques to do elastic and inelastic neutron scattering at steady-state and pulsed sources are reviewed. The pressure cells available at most neutron scattering centres are capable of reaching pressures of the order of 5 GPa (50 kbar), and attempts to reach 10 GPa have been made. For elastic scattering, a comparison is made between neutron scattering and X-ray scattering at high pressure using rotating anode or synchrotron sources.

  20. Pressures Detector Calibration and Measurement

    CERN Document Server

    Kumara, I Made Gita

    2016-01-01

    This is report of my first and second projects (of 3) in NA61. I did data taking and analysis in order to do calibration of pressure detectors and verified it. I analyzed the data by ROOT software using the C ++ programming language. The first part of my project was determination of calibration factor of pressure sensors. Based on that result, I examined the relation between pressure drop, gas flow rate of in paper filter and its diameter.