WorldWideScience

Sample records for high precipitation increases

  1. Consistent increase in High Asia's runoff due to increasing glacier melt and precipitation

    NARCIS (Netherlands)

    Lutz, A. F.; Immerzeel, W. W.|info:eu-repo/dai/nl/290472113; Shrestha, A. B.; Bierkens, M. F P|info:eu-repo/dai/nl/125022794

    Rivers originating in the high mountains of Asia are among the most meltwater-dependent river systems on Earth, yet large human populations depend on their resources downstream1. Across High Asias river basins, there is large variation in the contribution of glacier and snow melt to total runoff 2,

  2. Precipitation variability increases in a warmer climate.

    Science.gov (United States)

    Pendergrass, Angeline G; Knutti, Reto; Lehner, Flavio; Deser, Clara; Sanderson, Benjamin M

    2017-12-21

    Understanding changes in precipitation variability is essential for a complete explanation of the hydrologic cycle's response to warming and its impacts. While changes in mean and extreme precipitation have been studied intensively, precipitation variability has received less attention, despite its theoretical and practical importance. Here, we show that precipitation variability in most climate models increases over a majority of global land area in response to warming (66% of land has a robust increase in variability of seasonal-mean precipitation). Comparing recent decades to RCP8.5 projections for the end of the 21 st century, we find that in the global, multi-model mean, precipitation variability increases 3-4% K -1 globally, 4-5% K -1 over land and 2-4% K -1 over ocean, and is remarkably robust on a range of timescales from daily to decadal. Precipitation variability increases by at least as much as mean precipitation and less than moisture and extreme precipitation for most models, regions, and timescales. We interpret this as being related to an increase in moisture which is partially mitigated by weakening circulation. We show that changes in observed daily variability in station data are consistent with increased variability.

  3. Global warming without global mean precipitation increase?

    Science.gov (United States)

    Salzmann, Marc

    2016-06-01

    Global climate models simulate a robust increase of global mean precipitation of about 1.5 to 2% per kelvin surface warming in response to greenhouse gas (GHG) forcing. Here, it is shown that the sensitivity to aerosol cooling is robust as well, albeit roughly twice as large. This larger sensitivity is consistent with energy budget arguments. At the same time, it is still considerably lower than the 6.5 to 7% K(-1) decrease of the water vapor concentration with cooling from anthropogenic aerosol because the water vapor radiative feedback lowers the hydrological sensitivity to anthropogenic forcings. When GHG and aerosol forcings are combined, the climate models with a realistic 20th century warming indicate that the global mean precipitation increase due to GHG warming has, until recently, been completely masked by aerosol drying. This explains the apparent lack of sensitivity of the global mean precipitation to the net global warming recently found in observations. As the importance of GHG warming increases in the future, a clear signal will emerge.

  4. Heating-insensitive scale increase caused by convective precipitation

    Science.gov (United States)

    Haerter, Jan; Moseley, Christopher; Berg, Peter

    2017-04-01

    The origin of intense convective extremes and their unusual temperature dependence has recently challenged traditional thermodynamic arguments, based on the Clausius-Clapeyron relation. In a sequence of studies (Lenderink and v. Mejgaard, Nat Geosc, 2008; Berg, Haerter, Moseley, Nat Geosc, 2013; and Moseley, Hohenegger, Berg, Haerter, Nat Geosc, 2016) the argument of convective-type precipitation overcoming the 7%/K increase in extremes by dynamical, rather than thermodynamic, processes has been promoted. How can the role of dynamical processes be approached for precipitating convective cloud? One-phase, non-precipitating Rayleigh-Bénard convection is a classical problem in complex systems science. When a fluid between two horizontal plates is sufficiently heated from below, convective rolls spontaneously form. In shallow, non-precipitating atmospheric convection, rolls are also known to form under specific conditions, with horizontal scales roughly proportional to the boundary layer height. Here we explore within idealized large-eddy simulations, how the scale of convection is modified, when precipitation sets in and intensifies in the course of diurnal solar heating. Before onset of precipitation, Bénard cells with relatively constant diameter form, roughly on the scale of the atmospheric boundary layer. We find that the onset of precipitation then signals an approximately linear (in time) increase in horizontal scale. This scale increase progresses at a speed which is rather insensitive to changes in surface temperature or changes in the rate at which boundary conditions change, hinting at spatial characteristics, rather than temperature, as a possible control on spatial scales of convection. When exploring the depth of spatial correlations, we find that precipitation onset causes a sudden disruption of order and a subsequent complete disintegration of organization —until precipitation eventually ceases. Returning to the initial question of convective

  5. Increasing importance of precipitation variability on global livestock grazing lands

    Science.gov (United States)

    Sloat, Lindsey L.; Gerber, James S.; Samberg, Leah H.; Smith, William K.; Herrero, Mario; Ferreira, Laerte G.; Godde, Cécile M.; West, Paul C.

    2018-03-01

    Pastures and rangelands underpin global meat and milk production and are a critical resource for millions of people dependent on livestock for food security1,2. Forage growth, which is highly climate dependent3,4, is potentially vulnerable to climate change, although precisely where and to what extent remains relatively unexplored. In this study, we assess climate-based threats to global pastures, with a specific focus on changes in within- and between-year precipitation variability (precipitation concentration index (PCI) and coefficient of variation of precipitation (CVP), respectively). Relating global satellite measures of vegetation greenness (such as the Normalized Difference Vegetation Index; NDVI) to key climatic factors reveals that CVP is a significant, yet often overlooked, constraint on vegetation productivity across global pastures. Using independent stocking data, we found that areas with high CVP support lower livestock densities than less-variable regions. Globally, pastures experience about a 25% greater year-to-year precipitation variation (CVP = 0.27) than the average global land surface area (0.21). Over the past century, CVP has generally increased across pasture areas, although both positive (49% of pasture area) and negative (31% of pasture area) trends exist. We identify regions in which livestock grazing is important for local food access and economies, and discuss the potential for pasture intensification in the context of long-term regional trends in precipitation variability.

  6. Enhanced precipitation variability decreases grass- and increases shrub-productivity

    Science.gov (United States)

    Gherardi, Laureano A.; Sala, Osvaldo E.

    2015-01-01

    Although projections of precipitation change indicate increases in variability, most studies of impacts of climate change on ecosystems focused on effects of changes in amount of precipitation, overlooking precipitation variability effects, especially at the interannual scale. Here, we present results from a 6-y field experiment, where we applied sequences of wet and dry years, increasing interannual precipitation coefficient of variation while maintaining a precipitation amount constant. Increased precipitation variability significantly reduced ecosystem primary production. Dominant plant-functional types showed opposite responses: perennial-grass productivity decreased by 81%, whereas shrub productivity increased by 67%. This pattern was explained by different nonlinear responses to precipitation. Grass productivity presented a saturating response to precipitation where dry years had a larger negative effect than the positive effects of wet years. In contrast, shrubs showed an increasing response to precipitation that resulted in an increase in average productivity with increasing precipitation variability. In addition, the effects of precipitation variation increased through time. We argue that the differential responses of grasses and shrubs to precipitation variability and the amplification of this phenomenon through time result from contrasting root distributions of grasses and shrubs and competitive interactions among plant types, confirmed by structural equation analysis. Under drought conditions, grasses reduce their abundance and their ability to absorb water that then is transferred to deep soil layers that are exclusively explored by shrubs. Our work addresses an understudied dimension of climate change that might lead to widespread shrub encroachment reducing the provisioning of ecosystem services to society. PMID:26417095

  7. Developing precipitation hardenable high entropy alloys

    Science.gov (United States)

    Gwalani, Bharat

    High entropy alloys (HEAs) is a concept wherein alloys are constructed with five or more elements mixed in equal proportions; these are also known as multi-principle elements (MPEs) or complex concentrated alloys (CCAs). This PhD thesis dissertation presents research conducted to develop precipitation-hardenable high entropy alloys using a much-studied fcc-based equi-atomic quaternary alloy (CoCrFeNi). Minor additions of aluminium make the alloy amenable for precipitating ordered intermetallic phases in an fcc matrix. Aluminum also affects grain growth kinetics and Hall-Petch hardenability. The use of a combinatorial approach for assessing composition-microstructure-property relationships in high entropy alloys, or more broadly in complex concentrated alloys; using laser deposited compositionally graded AlxCrCuFeNi 2 (0 mechanically processed via conventional techniques. The phase stability and mechanical properties of these alloys have been investigated and will be presented. Additionally, the activation energy for grain growth as a function of Al content in these complex alloys has also been investigated. Change in fcc grain growth kinetic was studied as a function of aluminum; the apparent activation energy for grain growth increases by about three times going from Al0.1CoCrFeNi (3% Al (at%)) to Al0.3CoCrFeNi. (7% Al (at%)). Furthermore, Al addition leads to the precipitation of highly refined ordered L12 (gamma') and B2 precipitates in Al0.3CoCrFeNi. A detailed investigation of precipitation of the ordered phases in Al0.3CoCrFeNi and their thermal stability is done using atom probe tomography (APT), transmission electron microscopy (TEM) and Synchrotron X-ray in situ and ex situ analyses. The alloy strengthened via grain boundary strengthening following the Hall-Petch relationship offers a large increment of strength with small variation in grain size. Tensile strength of the Al0.3CoFeNi is increased by 50% on precipitation fine-scale gamma' precipitates

  8. Characterization of increased persistence and intensity of precipitation in the northeastern United States

    Science.gov (United States)

    Guilbert, Justin; Betts, Alan K.; Rizzo, Donna M.; Beckage, Brian; Bomblies, Arne

    2015-03-01

    We present evidence of increasing persistence in daily precipitation in the northeastern United States that suggests that global circulation changes are affecting regional precipitation patterns. Meteorological data from 222 stations in 10 northeastern states are analyzed using Markov chain parameter estimates to demonstrate that a significant mode of precipitation variability is the persistence of precipitation events. We find that the largest region-wide trend in wet persistence (i.e., the probability of precipitation in 1 day and given precipitation in the preceding day) occurs in June (+0.9% probability per decade over all stations). We also find that the study region is experiencing an increase in the magnitude of high-intensity precipitation events. The largest increases in the 95th percentile of daily precipitation occurred in April with a trend of +0.7 mm/d/decade. We discuss the implications of the observed precipitation signals for watershed hydrology and flood risk.

  9. Strong increase in convective precipitation in response to higher temperatures

    DEFF Research Database (Denmark)

    Berg, P.; Moseley, C.; Härter, Jan Olaf Mirko

    2013-01-01

    Precipitation changes can affect society more directly than variations in most other meteorological observables, but precipitation is difficult to characterize because of fluctuations on nearly all temporal and spatial scales. In addition, the intensity of extreme precipitation rises markedly...... at higher temperature, faster than the rate of increase in the atmosphere's water-holding capacity, termed the Clausius-Clapeyron rate. Invigoration of convective precipitation (such as thunderstorms) has been favoured over a rise in stratiform precipitation (such as large-scale frontal precipitation......) as a cause for this increase , but the relative contributions of these two types of precipitation have been difficult to disentangle. Here we combine large data sets from radar measurements and rain gauges over Germany with corresponding synoptic observations and temperature records, and separate convective...

  10. Enhanced interannual precipitation variability increases plant functional diversity that in turn ameliorates negative impact on productivity.

    Science.gov (United States)

    Gherardi, Laureano A; Sala, Osvaldo E

    2015-12-01

    Although precipitation interannual variability is projected to increase due to climate change, effects of changes in precipitation variance have received considerable less attention than effects of changes in the mean state of climate. Interannual precipitation variability effects on functional diversity and its consequences for ecosystem functioning are assessed here using a 6-year rainfall manipulation experiment. Five precipitation treatments were switched annually resulting in increased levels of precipitation variability while maintaining average precipitation constant. Functional diversity showed a positive response to increased variability due to increased evenness. Dominant grasses decreased and rare plant functional types increased in abundance because grasses showed a hump-shaped response to precipitation with a maximum around modal precipitation, whereas rare species peaked at high precipitation values. Increased functional diversity ameliorated negative effects of precipitation variability on primary production. Rare species buffered the effect of precipitation variability on the variability in total productivity because their variance decreases with increasing precipitation variance. © 2015 John Wiley & Sons Ltd/CNRS.

  11. Is convective precipitation increasing? The case of Catalonia

    Science.gov (United States)

    Llasat, M. C.; Marcos, R.; Turco, M.

    2012-04-01

    A recent work (Turco and Llasat, 2011) has been performed to analyse the trends of the ETCCDI (Expert Team on Climate Change Detection and Indices) precipitation indices in Catalonia (NE Iberian Peninsula) from 1951 to 2003, calculated from a interpolated dataset of daily precipitation, namely SPAIN02, regular at 0.2° horizontal resolution. This work has showed that no general trends at a regional scale have been observed, considering the annual and the seasonal regional values, and only the consecutive dry days index (CDD) at annual scale shows a locally coherent spatial trend pattern. Simultaneously, Llasat et al (2009, 2010) have showed an important increase of flash-flood events in the same region. Although aspects related with vulnerability, exposure and changes in uses of soil have been found as the main responsible of this increase, a major knowledge on the evolution of high rainfall events is mandatory. Heavy precipitation is usually associated to convective precipitation and therefore the analysis of the latter is a good indicator of it. Particularly, in Catalonia, funding was raised to define a parameter, designated as β, related with the greater or lesser convective character of the precipitation (Llasat, 2001). This parameter estimates the contribution of convective precipitation to total precipitation using 1-min or 5-min rainfall intensities usually estimated by rain gauges and it can be also analysed by means of the meteorological radar (Llasat et al, 2007). Its monthly distribution shows a maximum in August, followed by September, which are the months with the major number of flash-floods in Catalonia. This parameter also allows distinguishing between different kinds of precipitation events taking into account the degree of convective contribution. The main problem is the lack of long rainfall rate series that allow analysing trends in convective precipitation. The second one is related with its heterogeneous spatial and temporal distribution. To

  12. MCS precipitation and downburst intensity response to increased aerosol concentrations

    Science.gov (United States)

    Clavner, M.; Cotton, W. R.; van den Heever, S. C.

    2015-12-01

    Mesoscale convective systems (MCSs) are important contributors to rainfall in the High Plains of the United States as well as producers of severe weather such as hail, tornados and straight-line wind events known as derechos. Past studies have shown that changes in aerosol concentrations serving as cloud condensation nuclei (CCN) alter the MCS hydrometeor characteristics which in turn modify precipitation yield, downdraft velocity, cold-pool strength, storm propagation and the potential for severe weather to occur. In this study, the sensitivity of MCS precipitation characteristics and convective downburst velocities associated with a derecho to changes in CCN concentrations were examined by simulating a case study using the Regional Atmospheric Modeling System (RAMS). The case study of the 8 May 2009 "Super-Derecho" MCS was chosen since it produced a swath of widespread wind damage in association with an embedded large-scale bow echo, over a broad region from the High Plains of western Kansas to the foothills of the Appalachians. The sensitivity of the storm to changes in CCN concentrations was examined by conducting a set of three simulations which differed in the initial aerosol concentration based on output from the 3D chemical transport model, GEOS-Chem. Results from this study indicate that while increasing CCN concentrations led to an increase in precipitation rates, the changes to the derecho strength were not linear. A moderate increase in aerosol concentration reduced the derecho strength, while the simulation with the highest aerosol concentrations increased the derecho intensity. These changes are attributed to the impact of enhanced CCN concentration on the production of convective downbursts. An analysis of aerosol loading impacts on these MCS features will be presented.

  13. Streamflow response to increasing precipitation extremes altered by forest management

    Science.gov (United States)

    Charlene N. Kelly; Kevin J. McGuire; Chelcy Ford Miniat; James M. Vose

    2016-01-01

    Increases in extreme precipitation events of floods and droughts are expected to occur worldwide. The increase in extreme events will result in changes in streamflow that are expected to affect water availability for human consumption and aquatic ecosystem function. We present an analysis that may greatly improve current streamflow models by quantifying the...

  14. Ranch profitability given increased precipitation variability and flexible stocking

    Science.gov (United States)

    Forage and cattle performance relationships with spring precipitation, combined with cattle market price variability, were incorporated into a ranch level model to determine if addition of a yearling enterprise to the base cow-calf herd would improve profitability with increasing (25% and 50% greate...

  15. Increasing precipitation volatility in twenty-first-century California

    Science.gov (United States)

    Swain, Daniel L.; Langenbrunner, Baird; Neelin, J. David; Hall, Alex

    2018-05-01

    Mediterranean climate regimes are particularly susceptible to rapid shifts between drought and flood—of which, California's rapid transition from record multi-year dryness between 2012 and 2016 to extreme wetness during the 2016-2017 winter provides a dramatic example. Projected future changes in such dry-to-wet events, however, remain inadequately quantified, which we investigate here using the Community Earth System Model Large Ensemble of climate model simulations. Anthropogenic forcing is found to yield large twenty-first-century increases in the frequency of wet extremes, including a more than threefold increase in sub-seasonal events comparable to California's `Great Flood of 1862'. Smaller but statistically robust increases in dry extremes are also apparent. As a consequence, a 25% to 100% increase in extreme dry-to-wet precipitation events is projected, despite only modest changes in mean precipitation. Such hydrological cycle intensification would seriously challenge California's existing water storage, conveyance and flood control infrastructure.

  16. The effect of the precipitation of coherent and incoherent precipitates on the ductility and toughness of high-strength steel

    International Nuclear Information System (INIS)

    Hamano, R.

    1993-01-01

    The effect of the coexistence of coherent and incoherent precipitates, such as M 2 C and NiAl, on the ductility and plane strain fracture toughness of 5 wt pct Ni-2 wt pct Al-based high-strength steels was studied. In order to disperse coherent and incoherent precipitates, the heat treatments were carried out as follows: (a) austenitizing at 1373 K, (b) tempering at 1023 or 923 K for dispersing the incoherent precipitates of M 2 C and NiAl, and then (c) aging at 843 K for 2.4 ks to disperse the coherent precipitate of NiAl into the matrix, which contains incoherent precipitates, such as M 2 C and NiAl. The results were obtained as follows: (a) when the strengthening precipitates consist of coherent ones, such as M 2 C and/or NiAl, the ductility and toughness are extremely low, and (b) when the strengthening precipitates consist of coherent and incoherent precipitates, such as M 2 C and NiAl, the ductility and fracture toughness significantly increase with no loss in strength. It is shown that the coexistence of coherent and incoherent precipitates increases homogeneous deformation, thus preventing local strain concentration and early cleavage cracking. Accordingly, the actions of coherent precipitates in strengthening the matrix and of incoherent precipitates in promoting, homogeneous deformation can be expected to increase both the strength and toughness of the material

  17. Precipitation increases the occurrence of sporadic legionnaires' disease in Taiwan.

    Directory of Open Access Journals (Sweden)

    Nai-Tzu Chen

    Full Text Available Legionnaires' disease (LD is an acute form of pneumonia, and changing weather is considered a plausible risk factor. Yet, the relationship between weather and LD has rarely been investigated, especially using long-term daily data. In this study, daily data was used to evaluate the impacts of precipitation, temperature, and relative humidity on LD occurrence in Taiwan from 1995-2011. A time-stratified 2:1 matched-period case-crossover design was used to compare each case with self-controlled data using a conditional logistic regression analysis, and odds ratios (ORs for LD occurrence was estimated. The city, gender and age were defined as a stratum for each matched set to modify the effects. For lag day- 0 to 15, the precipitation at lag day-11 significantly affected LD occurrence (p0.05. In conclusion, in warm, humid regions, an increase of daily precipitation is likely to be a critical weather factor triggering LD occurrence where the risk is found particularly significant at an 11-day lag. Additionally, precipitation at 21-40 and 61-80 mm might make LD occurrence more likely.

  18. High Nitrogen Austenitic Stainless Steel Precipitation During Isothermal Annealing

    OpenAIRE

    Maria Domankova; Katarína Bártová; Ivan Slatkovský; Peter Pinke

    2016-01-01

    The time-temperature-precipitation in high-nitrogen austenitic stainless steel was investigated using light optical microscopy, transmission electron microscopy, selected area diffraction and energy-dispersive X-ray spectroscopy. The isothermal precipitation kinetics curves and the corresponding precipitation activation energy were obtained. The diffusion activation energy of M2N precipitation is 129 kJ/mol. The results show that critical temperature for M2N precipitation is about 825°C with ...

  19. Will climate change increase the risk for critical infrastructure failures in Europe due to extreme precipitation?

    Science.gov (United States)

    Nissen, Katrin; Ulbrich, Uwe

    2016-04-01

    An event based detection algorithm for extreme precipitation is applied to a multi-model ensemble of regional climate model simulations. The algorithm determines extent, location, duration and severity of extreme precipitation events. We assume that precipitation in excess of the local present-day 10-year return value will potentially exceed the capacity of the drainage systems that protect critical infrastructure elements. This assumption is based on legislation for the design of drainage systems which is in place in many European countries. Thus, events exceeding the local 10-year return value are detected. In this study we distinguish between sub-daily events (3 hourly) with high precipitation intensities and long-duration events (1-3 days) with high precipitation amounts. The climate change simulations investigated here were conducted within the EURO-CORDEX framework and exhibit a horizontal resolution of approximately 12.5 km. The period between 1971-2100 forced with observed and scenario (RCP 8.5 and RCP 4.5) greenhouse gas concentrations was analysed. Examined are changes in event frequency, event duration and size. The simulations show an increase in the number of extreme precipitation events for the future climate period over most of the area, which is strongest in Northern Europe. Strength and statistical significance of the signal increase with increasing greenhouse gas concentrations. This work has been conducted within the EU project RAIN (Risk Analysis of Infrastructure Networks in response to extreme weather).

  20. A New Inter-Hemispheric Teleconnection Increases Predictability of Winter Precipitation in Southwestern US

    Science.gov (United States)

    Mamalakis, A.; Yu, J. Y.; Randerson, J. T.; AghaKouchak, A.; Foufoula-Georgiou, E.

    2017-12-01

    Early and reliable prediction of seasonal precipitation in the southwestern US (SWUS) remains a challenge with significant implications for the economy, water security and ecosystem management of the region. Traditional drivers of winter precipitation in the SWUS have been linked to the El Niño-Southern Oscillation (ENSO), decadal/multidecadal oscillations of the sea surface temperature in northern Pacific and Atlantic oceans, and persistent high-pressure ridges over the Gulf of Alaska. However, ENSO as well as other climate modes exhibit weak statistical relationships with precipitation and low predictability as lead time increases. Grounded on the hypothesis that still undiscovered relationships between large-scale atmosphere-ocean dynamics and SWUS precipitation might exist, here we followed a diagnostic approach by which instead of restricting ourselves to the established teleconnections, we analyzed systematically the correlation of global sea surface temperature (SST) and geopotential height (GPH) with winter precipitation amounts in all climatic divisions in the SWUS, for 1950-2015. Our results show that late-summer persistent SST and GPH anomalies in the subtropical southwestern Pacific are strongly connected with winter precipitation in most climatic divisions, exhibiting higher correlation values than ENSO, and thus increasing the potential for earlier and more accurate precipitation prediction. Cross validation and 30-year running average analysis starting in 1950 suggest an amplification of the detected teleconnections over the past three to four decades. The latter is most likely a result of the reported expansion of the tropics, which has started after the 1980s, and allows SST or GPH variability at lower latitudes to affect the meridional atmospheric circulation. Our work highlights the need to understand the dynamic nature of the coupled atmosphere-ocean system in a changing climate for improving future predictions of regional precipitation.

  1. High Nitrogen Austenitic Stainless Steel Precipitation During Isothermal Annealing

    Directory of Open Access Journals (Sweden)

    Maria Domankova

    2016-07-01

    Full Text Available The time-temperature-precipitation in high-nitrogen austenitic stainless steel was investigated using light optical microscopy, transmission electron microscopy, selected area diffraction and energy-dispersive X-ray spectroscopy. The isothermal precipitation kinetics curves and the corresponding precipitation activation energy were obtained. The diffusion activation energy of M2N precipitation is 129 kJ/mol. The results show that critical temperature for M2N precipitation is about 825°C with the corresponding incubation period 2.5 min.

  2. Are recent severe floods in Xiang River basin of China linked with the increase extreme precipitation?

    Science.gov (United States)

    Cheng, L.; Du, J.

    2015-12-01

    The Xiang River, a main tributary of the Yangtze River, is subjected to high floods frequently in recent twenty years. Climate change, including abrupt shifts and fluctuations in precipitation is an important factor influencing hydrological extreme conditions. In addition, human activities are widely recognized as another reasons leading to high flood risk. With the effects of climate change and human interventions on hydrological cycle, there are several questions that need to be addressed. Are floods in the Xiang River basin getting worse? Whether the extreme streamflow shows an increasing tendency? If so, is it because the extreme rainfall events have predominant effect on floods? To answer these questions, the article detected existing trends in extreme precipitation and discharge using Mann-Kendall test. Continuous wavelet transform method was employed to identify the consistency of changes in extreme precipitation and discharge. The Pearson correlation analysis was applied to investigate how much degree of variations in extreme discharge can be explained by climate change. The results indicate that slightly upward trends can be detected in both extreme rainfalls and discharge in the upper region of Xiang River basin. For the most area of middle and lower river basin, the extreme rainfalls show significant positive trends, but the extreme discharge displays slightly upward trends with no significance at 90% confidence level. Wavelet transform analysis results illustrate that highly similar patterns of signal changes can be seen between extreme precipitation and discharge in upper section of the basin, while the changes in extreme precipitation for the middle and lower reaches do not always coincide with the extreme streamflow. The correlation coefficients of the wavelet transforms for the precipitation and discharge signals in most area of the basin pass the significance test. The conclusion may be drawn that floods in recent years are not getting worse in

  3. High-resolution projections of mean and extreme precipitations over China through PRECIS under RCPs

    Science.gov (United States)

    Zhu, Jinxin; Huang, Gordon; Wang, Xiuquan; Cheng, Guanhui; Wu, Yinghui

    2018-06-01

    The impact of global warming on the characteristics of mean and extreme precipitations over China is investigated by using the Providing REgional Climate Impacts for Studies (PRECIS) model. The PRECIS model was driven by the Hadley Centre Global Environment Model version 2 with Earth System components and coupling (HadGEM2-ES). The results of both models are analyzed in terms of mean precipitation and indices of precipitation extremes (R95p, R99p, SDII, WDF, and CWD) over China at the resolution of 25 km under the Representative Concentration Pathways 4.5 and 8.5 (RCP4.5 and RCP8.5) scenarios for the baseline period (1976-2005) and two future periods (2036-2065 and 2070-2099). With improved resolution, the PRECIS model is able to better represent the fine-scale physical process than HadGEM2-ES. It can provide reliable spatial patterns of precipitation and its related extremes with high correlations to observations. Moreover, there is a notable improvement in temporal patterns simulation through the PRECIS model. The PRECIS model better reproduces the regional annual cycle and frequencies of daily precipitation intensity than its driving GCM. Under RCP4.5 and RCP8.5, both the HadGEM2-ES and the precis project increasing annual precipitation over the entire country for two future periods. Precipitation increase in winter is greater than the increase in summer. The results suggest that increased radiative forcing from RCP4.5 to RCP8.5 would further intensify the magnitude of projected precipitation changes by both PRECIS and HadGEM2-ES. For example, some parts of south China with decreased precipitation under RCP4.5 would expect even less precipitation under RCP8.5; regions (northwest, northcentral and northeast China) with increased precipitation under RCP4.5 would expect more precipitation under RCP8.5. Apart from the projected increase in annual total precipitation, the results also suggest that there will be an increase in the days with precipitation higher than

  4. A test for Improvement of high resolution Quantitative Precipitation Estimation for localized heavy precipitation events

    Science.gov (United States)

    Lee, Jung-Hoon; Roh, Joon-Woo; Park, Jeong-Gyun

    2017-04-01

    Accurate estimation of precipitation is one of the most difficult and significant tasks in the area of weather diagnostic and forecasting. In the Korean Peninsula, heavy precipitations are caused by various physical mechanisms, which are affected by shortwave trough, quasi-stationary moisture convergence zone among varying air masses, and a direct/indirect effect of tropical cyclone. In addition to, various geographical and topographical elements make production of temporal and spatial distribution of precipitation is very complicated. Especially, localized heavy rainfall events in South Korea generally arise from mesoscale convective systems embedded in these synoptic scale disturbances. In weather radar data with high temporal and spatial resolution, accurate estimation of rain rate from radar reflectivity data is too difficult. Z-R relationship (Marshal and Palmer 1948) have adapted representatively. In addition to, several methods such as support vector machine (SVM), neural network, Fuzzy logic, Kriging were utilized in order to improve the accuracy of rain rate. These methods show the different quantitative precipitation estimation (QPE) and the performances of accuracy are different for heavy precipitation cases. In this study, in order to improve the accuracy of QPE for localized heavy precipitation, ensemble method for Z-R relationship and various techniques was tested. This QPE ensemble method was developed by a concept based on utilizing each advantage of precipitation calibration methods. The ensemble members were produced for a combination of different Z-R coefficient and calibration method.

  5. High-throughput computational search for strengthening precipitates in alloys

    International Nuclear Information System (INIS)

    Kirklin, S.; Saal, James E.; Hegde, Vinay I.; Wolverton, C.

    2016-01-01

    The search for high-strength alloys and precipitation hardened systems has largely been accomplished through Edisonian trial and error experimentation. Here, we present a novel strategy using high-throughput computational approaches to search for promising precipitate/alloy systems. We perform density functional theory (DFT) calculations of an extremely large space of ∼200,000 potential compounds in search of effective strengthening precipitates for a variety of different alloy matrices, e.g., Fe, Al, Mg, Ni, Co, and Ti. Our search strategy involves screening phases that are likely to produce coherent precipitates (based on small lattice mismatch) and are composed of relatively common alloying elements. When combined with the Open Quantum Materials Database (OQMD), we can computationally screen for precipitates that either have a stable two-phase equilibrium with the host matrix, or are likely to precipitate as metastable phases. Our search produces (for the structure types considered) nearly all currently known high-strength precipitates in a variety of fcc, bcc, and hcp matrices, thus giving us confidence in the strategy. In addition, we predict a number of new, currently-unknown precipitate systems that should be explored experimentally as promising high-strength alloy chemistries.

  6. High population increase rates.

    Science.gov (United States)

    1991-09-01

    In addition to its economic and ethnic difficulties, the USSR faces several pressing demographic problems, including high population increase rates in several of its constituent republics. It has now become clear that although the country's rigid centralized planning succeeded in covering the basic needs of people, it did not lead to welfare growth. Since the 1970s, the Soviet economy has remained sluggish, which as led to increase in the death and birth rates. Furthermore, the ideology that held that demography could be entirely controlled by the country's political and economic system is contradicted by current Soviet reality, which shows that religion and ethnicity also play a significant role in demographic dynamics. Currently, Soviet republics fall under 2 categories--areas with high or low natural population increase rates. Republics with low rates consist of Christian populations (Armenia, Moldavia, Georgia, Byelorussia, Russia, Lithuania, Estonia, Latvia, Ukraine), while republics with high rates are Muslim (Tadzhikistan, Uzbekistan, Turkmenistan, Kirgizia, Azerbaijan Kazakhstan). The later group has natural increase rates as high as 3.3%. Although the USSR as a whole is not considered a developing country, the later group of republics fit the description of the UNFPA's priority list. Another serious demographic issue facing the USSR is its extremely high rate of abortion. This is especially true in the republics of low birth rates, where up to 60% of all pregnancies are terminated by induced abortions. Up to 1/5 of the USSR's annual health care budget is spent on clinical abortions -- money which could be better spent on the production of contraceptives. Along with the recent political and economic changes, the USSR is now eager to deal with its demographic problems.

  7. The response of a simulated mesoscale convective system to increased aerosol pollution: Part I: Precipitation intensity, distribution, and efficiency

    Science.gov (United States)

    Clavner, Michal; Cotton, William R.; van den Heever, Susan C.; Saleeby, Stephen M.; Pierce, Jeffery R.

    2018-01-01

    Mesoscale Convective Systems (MCSs) are important contributors to rainfall in the High Plains of the United States and elsewhere in the world. It is therefore of interest to understand how different aerosols serving as cloud condensation nuclei (CCN) may impact the total amount, rates and spatial distribution of precipitation produced by MCSs. In this study, different aerosol concentrations and their effects on precipitation produced by an MCS are examined by simulating the 8 May 2009 "Super-Derecho" MCS using the Regional Atmospheric Modeling System (RAMS), a cloud-resolving model (CRM) with sophisticated aerosol and microphysical parameterizations. Three simulations were conducted that differed only in the initial concentration, spatial distribution, and chemical composition of aerosols. Aerosol fields were derived from the output of GEOS-Chem, a 3D chemical transport numerical model. Results from the RAMS simulations show that the total domain precipitation was not significantly affected by variations in aerosol concentrations, however, the pollution aerosols altered the precipitation characteristics. The more polluted simulations exhibited higher precipitation rates, higher bulk precipitation efficiency, a larger area with heavier precipitation, and a smaller area with lighter precipitation. These differences arose as a result of aerosols enhancing precipitation in the convective region of the MCS while suppressing precipitation from the MCS's stratiform-anvil. In the convective region, several processes likely contributed to an increase of precipitation. First, owing to the very humid environment of this storm, the enhanced amount of cloud water available to be collected overwhelmed the reduction in precipitation efficiency associated with the aerosol-induced production of smaller droplets which led to a net increase in the conversion of cloud droplets to precipitation. Second, higher aerosol concentrations led to invigoration of convective updrafts which

  8. Precipitation of hydrides in high purity niobium after different treatments

    Energy Technology Data Exchange (ETDEWEB)

    Barkov, F.; Romanenko, A.; Trenikhina, Y.; Grassellino, A.

    2013-01-01

    Precipitation of lossy non-superconducting niobium hydrides represents a known problem for high purity niobium in superconducting applications. Using cryogenic optical and laser confocal scanning microscopy we have directly observed surface precipitation and evolution of niobium hydrides in samples after different treatments used for superconducting RF cavities for particle acceleration. Precipitation is shown to occur throughout the sample volume, and the growth of hydrides is well described by the fast diffusion-controlled process in which almost all hydrogen is precipitated at $T=140$~K within $\\sim30$~min. 120$^{\\circ}$C baking and mechanical deformation are found to affect hydride precipitation through their influence on the number of nucleation and trapping centers.

  9. Precipitation Kinetics of Cr2N in High Nitrogen Austenitic Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    SHI Feng; WANG Li-jun; CUI Wen-fang; LIU Chun-ming

    2008-01-01

    The precipitation behavior of Cr2N during isothermal aging in the temperature range from 700℃to 950℃ in Fe-18Cr-12Mn-0.48N(in mass percent)high nitrogen austenitic stainless steel,including morphology and content of precipitate,was investigated using optical microscopy,scanning electron microscopy,and transmission electron microscopy.The isothermal precipitation kinetics curve of Cr2N and the corresponding precipitation activation energy were obtained.The results show that Cr2N phase precipitates in a cellular way and its morphology is transformed from initial granular precipitates to lamellar ones in the cell with increasing aging time.The nose temperature of Cr2N precipitation is about 800℃,with a corresponding incubation period of 30 min,and the ceiling temperature of Cr2N precipitation is 950℃.The diffusion activation energy of Cr2N precipitation is 296 kJ/mol.

  10. El Nino-like Teleconnection Increases California Precipitation in Response to Warming

    Science.gov (United States)

    Allen, R.

    2017-12-01

    Future California (CA) precipitation projections, including those from the most recent Climate Model Intercomparison Project (CMIP5), remain uncertain. This uncertainty is related to several factors, including relatively large internal climate variability, model shortcomings, and because CA lies within a transition zone, where mid-latitude regions are expected to become wetter and subtropical regions drier. Here, we use a multitude of models to show CA may receive more precipitation in the future under a business-as-usual scenario. The boreal winter season-when most of the CA precipitation increase occurs-is associated with robust changes in the mean circulation reminiscent of an El Nino teleconnection. Using idealized simulations with two different models, we further show that warming of tropical Pacific sea surface temperatures accounts for these changes. Models that better simulate the observed El Nino-CA precipitation teleconnection yield larger, and more consistent increases in CA precipitation through the twenty-first century.

  11. El Niño-like teleconnection increases California precipitation in response to warming

    Science.gov (United States)

    Allen, Robert J.; Luptowitz, Rainer

    2017-07-01

    Future California (CA) precipitation projections, including those from the most recent Climate Model Intercomparison Project (CMIP5), remain uncertain. This uncertainty is related to several factors, including relatively large internal climate variability, model shortcomings, and because CA lies within a transition zone, where mid-latitude regions are expected to become wetter and subtropical regions drier. Here, we use a multitude of models to show CA may receive more precipitation in the future under a business-as-usual scenario. The boreal winter season-when most of the CA precipitation increase occurs-is associated with robust changes in the mean circulation reminiscent of an El Niño teleconnection. Using idealized simulations with two different models, we further show that warming of tropical Pacific sea surface temperatures accounts for these changes. Models that better simulate the observed El Niño-CA precipitation teleconnection yield larger, and more consistent increases in CA precipitation through the twenty-first century.

  12. Dualism of precipitation morphology in high strength low alloy steel

    International Nuclear Information System (INIS)

    Chih-Yuan, Chen; Chien-Chon, Chen; Jer-Ren, Yang

    2015-01-01

    While the role of microalloying elements on precipitation strengthening in ferrite matrix during austenite/ferrite transformation is quite clear, some uncertainty still exists concerning the variability of the microhardness distribution of ferrite grains in the isothermal holding condition. The objective of the present study was to clarify the intrinsic characteristics of carbide precipitation morphology in the ferrite matrix under different processing temperatures and times and to correlate it with austenite decomposition kinetics to elucidate why a large microhardness distribution occurs at low isothermal holding temperature. Better understanding of carbide precipitation behavior can help researchers to determine the root cause of variation in microhardness distribution, which would allow metallurgists to produce high quality steels. Measurement with a Vickers hardness indenter revealed that, in specimens isothermally held at 625 °C, the range of Vickers hardness distribution was 240–420 after 5 min of isothermal holding, and 270–340 after 60 min. For specimens isothermally held at 725 °C, the range of Vickers hardness distribution was 200–330 for 5 min of isothermal holding, and 200–250 for 60 min. Therefore, the average microhardness decreased with the isothermal holding temperature and time, and a larger range of distribution occurred with short isothermal holding times. Transmission electron microscopy (TEM) images showed that interface precipitation and random precipitation can occur within the same ferrite grain. The reason is that the austenite decomposition rate varies with transformation temperature and time. An excessively fast austenite/ferrite interface movement velocity, which usually happens in small ferrite grains, would cause these ferrite grains with microalloying elements to exceed their solubility. Furthermore, these microalloying elements will be precipitated randomly after isothermal holding at longer times. Consequently, a large

  13. Dualism of precipitation morphology in high strength low alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Chih-Yuan, Chen, E-mail: chen6563@gmail.com [Department of Energy Engineering, National United University, Miaoli 36003, Taiwan (China); Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Chien-Chon, Chen [Department of Energy Engineering, National United University, Miaoli 36003, Taiwan (China); Jer-Ren, Yang, E-mail: jryang@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2015-02-25

    While the role of microalloying elements on precipitation strengthening in ferrite matrix during austenite/ferrite transformation is quite clear, some uncertainty still exists concerning the variability of the microhardness distribution of ferrite grains in the isothermal holding condition. The objective of the present study was to clarify the intrinsic characteristics of carbide precipitation morphology in the ferrite matrix under different processing temperatures and times and to correlate it with austenite decomposition kinetics to elucidate why a large microhardness distribution occurs at low isothermal holding temperature. Better understanding of carbide precipitation behavior can help researchers to determine the root cause of variation in microhardness distribution, which would allow metallurgists to produce high quality steels. Measurement with a Vickers hardness indenter revealed that, in specimens isothermally held at 625 °C, the range of Vickers hardness distribution was 240–420 after 5 min of isothermal holding, and 270–340 after 60 min. For specimens isothermally held at 725 °C, the range of Vickers hardness distribution was 200–330 for 5 min of isothermal holding, and 200–250 for 60 min. Therefore, the average microhardness decreased with the isothermal holding temperature and time, and a larger range of distribution occurred with short isothermal holding times. Transmission electron microscopy (TEM) images showed that interface precipitation and random precipitation can occur within the same ferrite grain. The reason is that the austenite decomposition rate varies with transformation temperature and time. An excessively fast austenite/ferrite interface movement velocity, which usually happens in small ferrite grains, would cause these ferrite grains with microalloying elements to exceed their solubility. Furthermore, these microalloying elements will be precipitated randomly after isothermal holding at longer times. Consequently, a large

  14. Future increases in Arctic precipitation linked to local evaporation and sea-ice retreat.

    Science.gov (United States)

    Bintanja, R; Selten, F M

    2014-05-22

    Precipitation changes projected for the end of the twenty-first century show an increase of more than 50 per cent in the Arctic regions. This marked increase, which is among the highest globally, has previously been attributed primarily to enhanced poleward moisture transport from lower latitudes. Here we use state-of-the-art global climate models to show that the projected increases in Arctic precipitation over the twenty-first century, which peak in late autumn and winter, are instead due mainly to strongly intensified local surface evaporation (maximum in winter), and only to a lesser degree due to enhanced moisture inflow from lower latitudes (maximum in late summer and autumn). Moreover, we show that the enhanced surface evaporation results mainly from retreating winter sea ice, signalling an amplified Arctic hydrological cycle. This demonstrates that increases in Arctic precipitation are firmly linked to Arctic warming and sea-ice decline. As a result, the Arctic mean precipitation sensitivity (4.5 per cent increase per degree of temperature warming) is much larger than the global value (1.6 to 1.9 per cent per kelvin). The associated seasonally varying increase in Arctic precipitation is likely to increase river discharge and snowfall over ice sheets (thereby affecting global sea level), and could even affect global climate through freshening of the Arctic Ocean and subsequent modulations of the Atlantic meridional overturning circulation.

  15. Rapid decadal convective precipitation increase over Eurasia during the last three decades of the 20th century.

    Science.gov (United States)

    Ye, Hengchun; Fetzer, Eric J; Wong, Sun; Lambrigtsen, Bjorn H

    2017-01-01

    Convective precipitation-localized, short-lived, intense, and sometimes violent-is at the root of challenges associated with observation, simulation, and prediction of precipitation. The understanding of long-term changes in convective precipitation characteristics and their role in precipitation extremes and intensity over extratropical regions are imperative to future water resource management; however, they have been studied very little. We show that annual convective precipitation total has been increasing astonishingly fast, at a rate of 18.4%/°C, of which 16% is attributable to an increase in convective precipitation occurrence, and 2.4% is attributable to increased daily intensity based on the 35 years of two (combined) historical data sets of 3-hourly synoptic observations and daily precipitation. We also reveal that annual daily precipitation extreme has been increasing at a rate of about 7.4%/°C in convective events only. Concurrently, the overall increase in mean daily precipitation intensity is mostly due to increased convective precipitation, possibly at the expanse of nonconvective precipitation. As a result, transitional seasons are becoming more summer-like as convective becomes the dominant precipitation type that has accompanied higher daily extremes and intensity since the late 1980s. The data also demonstrate that increasing convective precipitation and daily extremes appear to be directly linearly associated with higher atmospheric water vapor accompanying a warming climate over northern Eurasia.

  16. Strengthening of stainless steel weldment by high temperature precipitation

    Directory of Open Access Journals (Sweden)

    Sergio Neves Monteiro

    2017-10-01

    Full Text Available The mechanical behavior and the strengthening mechanism of stainless steel welded joints at 600 °C have been investigated. The welds were composed of AISI 304 stainless steel, as base metal, and niobium containing AISI 347 stainless steel, as weld metal. The investigation was conducted by means of creep tests. The welded specimens were subjected to both high temperature (600 °C and long periods (up to 2000 h under constant load, and both mechanical properties and microstructural changes in the material were monitored. It was found that the exposure of the material at 600 °C under load contributes to a strengthening effect on the weld. The phenomenon might be correlated with an accelerated process of second phase precipitation hardening. Keywords: Stainless steel, Weld, AISI 304, Precipitation hardening

  17. Global warming precipitation accumulation increases above the current-climate cutoff scale

    Science.gov (United States)

    Sahany, Sandeep; Stechmann, Samuel N.; Bernstein, Diana N.

    2017-01-01

    Precipitation accumulations, integrated over rainfall events, can be affected by both intensity and duration of the storm event. Thus, although precipitation intensity is widely projected to increase under global warming, a clear framework for predicting accumulation changes has been lacking, despite the importance of accumulations for societal impacts. Theory for changes in the probability density function (pdf) of precipitation accumulations is presented with an evaluation of these changes in global climate model simulations. We show that a simple set of conditions implies roughly exponential increases in the frequency of the very largest accumulations above a physical cutoff scale, increasing with event size. The pdf exhibits an approximately power-law range where probability density drops slowly with each order of magnitude size increase, up to a cutoff at large accumulations that limits the largest events experienced in current climate. The theory predicts that the cutoff scale, controlled by the interplay of moisture convergence variance and precipitation loss, tends to increase under global warming. Thus, precisely the large accumulations above the cutoff that are currently rare will exhibit increases in the warmer climate as this cutoff is extended. This indeed occurs in the full climate model, with a 3 °C end-of-century global-average warming yielding regional increases of hundreds of percent to >1,000% in the probability density of the largest accumulations that have historical precedents. The probabilities of unprecedented accumulations are also consistent with the extension of the cutoff. PMID:28115693

  18. Global warming precipitation accumulation increases above the current-climate cutoff scale.

    Science.gov (United States)

    Neelin, J David; Sahany, Sandeep; Stechmann, Samuel N; Bernstein, Diana N

    2017-02-07

    Precipitation accumulations, integrated over rainfall events, can be affected by both intensity and duration of the storm event. Thus, although precipitation intensity is widely projected to increase under global warming, a clear framework for predicting accumulation changes has been lacking, despite the importance of accumulations for societal impacts. Theory for changes in the probability density function (pdf) of precipitation accumulations is presented with an evaluation of these changes in global climate model simulations. We show that a simple set of conditions implies roughly exponential increases in the frequency of the very largest accumulations above a physical cutoff scale, increasing with event size. The pdf exhibits an approximately power-law range where probability density drops slowly with each order of magnitude size increase, up to a cutoff at large accumulations that limits the largest events experienced in current climate. The theory predicts that the cutoff scale, controlled by the interplay of moisture convergence variance and precipitation loss, tends to increase under global warming. Thus, precisely the large accumulations above the cutoff that are currently rare will exhibit increases in the warmer climate as this cutoff is extended. This indeed occurs in the full climate model, with a 3 °C end-of-century global-average warming yielding regional increases of hundreds of percent to >1,000% in the probability density of the largest accumulations that have historical precedents. The probabilities of unprecedented accumulations are also consistent with the extension of the cutoff.

  19. Nanoscale co-precipitation and mechanical properties of a high-strength low-carbon steel

    International Nuclear Information System (INIS)

    Mulholland, Michael D.; Seidman, David N.

    2011-01-01

    Nanoscale co-precipitation in a novel high-strength low-carbon steel is studied in detail after isothermal aging. Atom-probe tomography is utilized to quantify the co-precipitation of co-located Cu precipitates and M 2 C (M is any combination of Cr, Mo, Fe, or Ti) carbide strengthening precipitates. Coarsening of Cu precipitates is offset by the nucleation and growth of M 2 C carbide precipitate, resulting in the maintenance of a yield strength of 1047 ± 7 MPa (152 ± 1 ksi) for as long as 320 h of aging time at 450 deg. C. Impact energies of 153 J (113 ± 6 ft-lb) and 144 J (106 ± 2 ft-lb) are measured at -30 deg. C and -60 deg. C, respectively. The co-location of Cu and M 2 C carbide precipitates results in non-stationary-state coarsening of the Cu precipitates. Synchrotron-source X-ray diffraction studies reveal that the measured 33% increase in impact toughness after aging for 80 h at 450 deg. C is due to dissolution of cementite, Fe 3 C, which is the source of carbon for the nucleation and growth of M 2 C carbide precipitates. Less than 1 vol.% austenite is observed for aging treatments at temperatures less than 600 deg. C, suggesting that transformation-induced plasticity does not play a significant role in the toughness of specimens aged at temperatures less than 600 deg. C. Aging treatments at temperatures greater than 600 deg. C produce more austenite, in the range 2-7%, but at the expense of yield strength.

  20. Significantly Increased Extreme Precipitation Expected in Europe and North America from Extratropical Storms

    Science.gov (United States)

    Hawcroft, M.; Hodges, K.; Walsh, E.; Zappa, G.

    2017-12-01

    For the Northern Hemisphere extratropics, changes in circulation are key to determining the impacts of climate warming. The mechanisms governing these circulation changes are complex, leading to the well documented uncertainty in projections of the future location of the mid-latitude storm tracks simulated by climate models. These storms are the primary source of precipitation for North America and Europe and generate many of the large-scale precipitation extremes associated with flooding and severe economic loss. Here, we show that in spite of the uncertainty in circulation changes, by analysing the behaviour of the storms themselves, we find entirely consistent and robust projections across an ensemble of climate models. In particular, we find that projections of change in the most intensely precipitating storms (above the present day 99th percentile) in the Northern Hemisphere are substantial and consistent across models, with large increases in the frequency of both summer (June-August, +226±68%) and winter (December-February, +186±34%) extreme storms by the end of the century. Regionally, both North America (summer +202±129%, winter +232±135%) and Europe (summer +390±148%, winter +318±114%) are projected to experience large increases in the frequency of intensely precipitating storms. These changes are thermodynamic and driven by surface warming, rather than by changes in the dynamical behaviour of the storms. Such changes in storm behaviour have the potential to have major impacts on society given intensely precipitating storms are responsible for many large-scale flooding events.

  1. Understanding dual precipitation strengthening in ultra-high strength low carbon steel containing nano-sized copper precipitates and carbides

    Science.gov (United States)

    Phaniraj, M. P.; Shin, Young-Min; Jung, Woo-Sang; Kim, Man-Ho; Choi, In-Suk

    2017-07-01

    Low carbon ferritic steel alloyed with Ti, Mo and Cu was hot rolled and interrupt cooled to produce nano-sized precipitates of copper and (Ti,Mo)C carbides. The steel had a tensile strength of 840 MPa, an increase in yield strength of 380 MPa over that of the plain carbon steel and reasonable ductility. Transmission electron microscopy and small angle neutron scattering were used to characterize size and volume fraction of the precipitates in the steels designed to form only copper precipitates and only (Ti,Mo)C carbides. The individual and combined precipitation strengthening contributions was calculated using the size and volume fraction of precipitates and compared with the measured values.

  2. Precipitation Effect on Mechanical Properties and Phase Stability of High Manganese Steel

    Science.gov (United States)

    Bae, Cheoljun; Kim, Rosa; Lee, Un-Hae; Kim, Jongryoul

    2017-09-01

    High manganese (Mn) steels are attractive for automotive applications due to their excellent tensile strength and superior elongation. However, the relatively low yield strength of Mn steels compared to other advanced high-strength steels is a critical problem limiting their use in structural parts. In order to increase the yield strength, the precipitation hardening effect of Mn steels was investigated by the addition of carbide-forming elements. Changes in the austenite phase stability were also evaluated in terms of stacking fault energy (SFE). As a result, fine V(C,N) precipitates were found to increase the yield strength effectively but to lower the SFE by the consumption of matrix carbons. For achieving precipitation hardening without sacrificing austenite stability, the soluble carbon content was discussed.

  3. Increased Kawasaki Disease Incidence Associated With Higher Precipitation and Lower Temperatures, Japan, 1991-2004.

    Science.gov (United States)

    Abrams, Joseph Y; Blase, Jennifer L; Belay, Ermias D; Uehara, Ritei; Maddox, Ryan A; Schonberger, Lawrence B; Nakamura, Yosikazu

    2018-06-01

    Kawasaki disease (KD) is an acute febrile vasculitis, which primarily affects children. The etiology of KD is unknown; while certain characteristics of the disease suggest an infectious origin, genetic or environmental factors may also be important. Seasonal patterns of KD incidence are well documented, but it is unclear whether these patterns are caused by changes in climate or by other unknown seasonal effects. The relationship between KD incidence and deviations from expected temperature and precipitation were analyzed using KD incidence data from Japanese nationwide epidemiologic surveys (1991-2004) and climate data from 136 weather stations of the Japan Meteorological Agency. Seven separate Poisson-distributed generalized linear regression models were run to examine the effects of temperature and precipitation on KD incidence in the same month as KD onset and the previous 1, 2, 3, 4, 5 and 6 months, controlling for geography as well as seasonal and long-term trends in KD incidence. KD incidence was negatively associated with temperature in the previous 2, 3, 4 and 5 months and positively associated with precipitation in the previous 1 and 2 months. The model that best predicted variations in KD incidence used climate data from the previous 2 months. An increase in total monthly precipitation by 100 mm was associated with increased KD incidence (rate ratio [RR] 1.012, 95% confidence interval [CI]: 1.005-1.019), and an increase of monthly mean temperature by 1°C was associated with decreased KD incidence (RR 0.984, 95% CI: 0.978-0.990). KD incidence was significantly affected by temperature and precipitation in previous months independent of other unknown seasonal factors. Climate data from the previous 2 months best predicted the variations in KD incidence. Although fairly minor, the effect of temperature and precipitation independent of season may provide additional clues to the etiology of KD.

  4. Spatio-Temporal Analysis of the Accuracy of Tropical Multisatellite Precipitation Analysis 3B42 Precipitation Data in Mid-High Latitudes of China

    Science.gov (United States)

    Cai, Yancong; Jin, Changjie; Wang, Anzhi; Guan, Dexin; Wu, Jiabing; Yuan, Fenghui; Xu, Leilei

    2015-01-01

    Satellite-based precipitation data have contributed greatly to quantitatively forecasting precipitation, and provides a potential alternative source for precipitation data allowing researchers to better understand patterns of precipitation over ungauged basins. However, the absence of calibration satellite data creates considerable uncertainties for The Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) 3B42 product over high latitude areas beyond the TRMM satellites latitude band (38°NS). This study attempts to statistically assess TMPA V7 data over the region beyond 40°NS using data obtained from numerous weather stations in 1998–2012. Comparative analysis at three timescales (daily, monthly and annual scale) indicates that adoption of a monthly adjustment significantly improved correlation at a larger timescale increasing from 0.63 to 0.95; TMPA data always exhibits a slight overestimation that is most serious at a daily scale (the absolute bias is 103.54%). Moreover, the performance of TMPA data varies across all seasons. Generally, TMPA data performs best in summer, but worst in winter, which is likely to be associated with the effects of snow/ice-covered surfaces and shortcomings of precipitation retrieval algorithms. Temporal and spatial analysis of accuracy indices suggest that the performance of TMPA data has gradually improved and has benefited from upgrades; the data are more reliable in humid areas than in arid regions. Special attention should be paid to its application in arid areas and in winter with poor scores of accuracy indices. Also, it is clear that the calibration can significantly improve precipitation estimates, the overestimation by TMPA in TRMM-covered area is about a third as much as that in no-TRMM area for monthly and annual precipitation. The systematic evaluation of TMPA over mid-high latitudes provides a broader understanding of satellite-based precipitation estimates, and these data are

  5. Spatio-temporal analysis of the accuracy of tropical multisatellite precipitation analysis 3B42 precipitation data in mid-high latitudes of China.

    Directory of Open Access Journals (Sweden)

    Yancong Cai

    Full Text Available Satellite-based precipitation data have contributed greatly to quantitatively forecasting precipitation, and provides a potential alternative source for precipitation data allowing researchers to better understand patterns of precipitation over ungauged basins. However, the absence of calibration satellite data creates considerable uncertainties for The Tropical Rainfall Measuring Mission (TRMM Multisatellite Precipitation Analysis (TMPA 3B42 product over high latitude areas beyond the TRMM satellites latitude band (38°NS. This study attempts to statistically assess TMPA V7 data over the region beyond 40°NS using data obtained from numerous weather stations in 1998-2012. Comparative analysis at three timescales (daily, monthly and annual scale indicates that adoption of a monthly adjustment significantly improved correlation at a larger timescale increasing from 0.63 to 0.95; TMPA data always exhibits a slight overestimation that is most serious at a daily scale (the absolute bias is 103.54%. Moreover, the performance of TMPA data varies across all seasons. Generally, TMPA data performs best in summer, but worst in winter, which is likely to be associated with the effects of snow/ice-covered surfaces and shortcomings of precipitation retrieval algorithms. Temporal and spatial analysis of accuracy indices suggest that the performance of TMPA data has gradually improved and has benefited from upgrades; the data are more reliable in humid areas than in arid regions. Special attention should be paid to its application in arid areas and in winter with poor scores of accuracy indices. Also, it is clear that the calibration can significantly improve precipitation estimates, the overestimation by TMPA in TRMM-covered area is about a third as much as that in no-TRMM area for monthly and annual precipitation. The systematic evaluation of TMPA over mid-high latitudes provides a broader understanding of satellite-based precipitation estimates, and these

  6. STAMMEX high resolution gridded daily precipitation dataset over Germany: a new potential for regional precipitation climate research

    Science.gov (United States)

    Zolina, Olga; Simmer, Clemens; Kapala, Alice; Mächel, Hermann; Gulev, Sergey; Groisman, Pavel

    2014-05-01

    We present new high resolution precipitation daily grids developed at Meteorological Institute, University of Bonn and German Weather Service (DWD) under the STAMMEX project (Spatial and Temporal Scales and Mechanisms of Extreme Precipitation Events over Central Europe). Daily precipitation grids have been developed from the daily-observing precipitation network of DWD, which runs one of the World's densest rain gauge networks comprising more than 7500 stations. Several quality-controlled daily gridded products with homogenized sampling were developed covering the periods 1931-onwards (with 0.5 degree resolution), 1951-onwards (0.25 degree and 0.5 degree), and 1971-2000 (0.1 degree). Different methods were tested to select the best gridding methodology that minimizes errors of integral grid estimates over hilly terrain. Besides daily precipitation values with uncertainty estimates (which include standard estimates of the kriging uncertainty as well as error estimates derived by a bootstrapping algorithm), the STAMMEX data sets include a variety of statistics that characterize temporal and spatial dynamics of the precipitation distribution (quantiles, extremes, wet/dry spells, etc.). Comparisons with existing continental-scale daily precipitation grids (e.g., CRU, ECA E-OBS, GCOS) which include considerably less observations compared to those used in STAMMEX, demonstrate the added value of high-resolution grids for extreme rainfall analyses. These data exhibit spatial variability pattern and trends in precipitation extremes, which are missed or incorrectly reproduced over Central Europe from coarser resolution grids based on sparser networks. The STAMMEX dataset can be used for high-quality climate diagnostics of precipitation variability, as a reference for reanalyses and remotely-sensed precipitation products (including the upcoming Global Precipitation Mission products), and for input into regional climate and operational weather forecast models. We will present

  7. A new approach for assimilation of two-dimensional radar precipitation in a high resolution NWP model

    Science.gov (United States)

    Korsholm, Ulrik; Petersen, Claus; Hansen Sass, Bent; Woetman, Niels; Getreuer Jensen, David; Olsen, Bjarke Tobias; GIll, Rasphal; Vedel, Henrik

    2014-05-01

    The DMI nowcasting system has been running in a pre-operational state for the past year. The system consists of hourly simulations with the High Resolution Limited Area weather model combined with surface and three-dimensional variational assimilation at each restart and nudging of satellite cloud products and radar precipitation. Nudging of a two-dimensional radar reflectivity CAPPI product is achieved using a new method where low level horizontal divergence is nudged towards pseudo observations. Pseudo observations are calculated based on an assumed relation between divergence and precipitation rate and the strength of the nudging is proportional to the offset between observed and modelled precipitation leading to increased moisture convergence below cloud base if there is an under-production of precipitation relative to the CAPPI product. If the model over-predicts precipitation, the low level moisture source is reduced, and in-cloud moisture is nudged towards environmental values. In this talk results will be discussed based on calculation of the fractions skill score in cases with heavy precipitation over Denmark. Furthermore, results from simulations combining reflectivity nudging and extrapolation of reflectivity will be shown. Results indicate that the new method leads to fast adjustment of the dynamical state of the model to facilitate precipitation release when the model precipitation intensity is too low. Removal of precipitation is also shown to be of importance and strong improvements were found in the position of the precipitation systems. Bias is reduced for low and extreme precipitation rates.

  8. Linking increases in hourly precipitation extremes to atmospheric temperature and moisture changes

    International Nuclear Information System (INIS)

    Lenderink, Geert; Van Meijgaard, Erik

    2010-01-01

    Relations between hourly precipitation extremes and atmospheric temperature and moisture derived for the present-day climate are studied with the aim of understanding the behavior (and the uncertainty in predictions) of hourly precipitation extremes in a changing climate. A dependency of hourly precipitation extremes on the daily mean 2 m temperature of approximately two times the Clausius-Clapeyron (CC) relation is found for temperatures above 10 deg. C. This is a robust relation obtained in four observational records across western Europe. A dependency following the CC relation can be explained by the observed increase in atmospheric (absolute) humidity with temperature, whereas the enhanced dependency (compared to the CC relation) appears to be caused by dynamical feedbacks owing to excess latent heat release in extreme showers. Integrations with the KNMI regional climate model RACMO2 at 25 km grid spacing show that changes in hourly precipitation extremes may indeed considerably exceed the prediction from the CC relation. The results suggests that increases of + 70% or even more are possible by the end of this century. However, a different regional model (CLM operated at ETHZ) predicts much smaller increases; this is probably caused by a too strong sensitivity of this model to a decrease in relative humidity.

  9. Structural and magnetic properties of cobalt ferrite nanoparticles synthesized by co-precipitation at increasing temperatures

    Science.gov (United States)

    Stein, C. R.; Bezerra, M. T. S.; Holanda, G. H. A.; André-Filho, J.; Morais, P. C.

    2018-05-01

    This study reports on the synthesis and characterization of cobalt ferrite (CoFe2O4) nanoparticles (NPs) synthesized by chemical co-precipitation in alkaline medium at increasing temperatures in the range of 27 °C to 100 °C. High-quality samples in the size range of 5 to 10 nm were produced using very low stirring speed (250 rpm) and moderate alkaline aqueous solution concentration (4.8 mol/L). Three samples were synthesized and characterized by x-ray diffraction (XRD) and room-temperature (RT) magnetization measurements. All samples present superparamagnetic (SPM) behavior at RT and Rietveld refinements confirm the inverse cubic spinel structure (space group Fd-3m (227)) with minor detectable impurity phase. As the synthesis temperature increases, structural parameters such as lattice constant and grain size change monotonically from 8.385 to 8.383 Å and from 5.8 to 7.4 nm, respectively. Likewise, as the synthesis temperature increases the NPs' magnetic moment and saturation magnetization increases monotonically from 2.6 ×103 to 16×103 μB and from 37 to 66 emu/g, respectively. The RT magnetization (M) versus applied field (H) curves were analyzed by the first-order Langevin function averaged out by a lognormal distribution function of magnetic moments. The excellent curve-fitting of the M versus H data is credited to a reduced particle-particle interaction due to both the SPM behavior and the existence of a surface amorphous shell layer (dead layer), the latter reducing systematically as the synthesis temperature increases.

  10. High resolution modelling of extreme precipitation events in urban areas

    Science.gov (United States)

    Siemerink, Martijn; Volp, Nicolette; Schuurmans, Wytze; Deckers, Dave

    2015-04-01

    The present day society needs to adjust to the effects of climate change. More extreme weather conditions are expected, which can lead to longer periods of drought, but also to more extreme precipitation events. Urban water systems are not designed for such extreme events. Most sewer systems are not able to drain the excessive storm water, causing urban flooding. This leads to high economic damage. In order to take appropriate measures against extreme urban storms, detailed knowledge about the behaviour of the urban water system above and below the streets is required. To investigate the behaviour of urban water systems during extreme precipitation events new assessment tools are necessary. These tools should provide a detailed and integral description of the flow in the full domain of overland runoff, sewer flow, surface water flow and groundwater flow. We developed a new assessment tool, called 3Di, which provides detailed insight in the urban water system. This tool is based on a new numerical methodology that can accurately deal with the interaction between overland runoff, sewer flow and surface water flow. A one-dimensional model for the sewer system and open channel flow is fully coupled to a two-dimensional depth-averaged model that simulates the overland flow. The tool uses a subgrid-based approach in order to take high resolution information of the sewer system and of the terrain into account [1, 2]. The combination of using the high resolution information and the subgrid based approach results in an accurate and efficient modelling tool. It is now possible to simulate entire urban water systems using extreme high resolution (0.5m x 0.5m) terrain data in combination with a detailed sewer and surface water network representation. The new tool has been tested in several Dutch cities, such as Rotterdam, Amsterdam and The Hague. We will present the results of an extreme precipitation event in the city of Schiedam (The Netherlands). This city deals with

  11. Adjustment of measurement errors to reconcile precipitation distribution in the high-altitude Indus basin

    NARCIS (Netherlands)

    Dahri, Zakir Hussain; Moors, Eddy; Ludwig, Fulco; Ahmad, Shakil; Khan, Asif; Ali, Irfan; Kabat, Pavel

    2018-01-01

    Precipitation in the high-altitude Indus basin governs its renewable water resources affecting water, energy and food securities. However, reliable estimates of precipitation climatology and associated hydrological implications are seriously constrained by the quality of observed data. As such,

  12. Spatial Ensemble Postprocessing of Precipitation Forecasts Using High Resolution Analyses

    Science.gov (United States)

    Lang, Moritz N.; Schicker, Irene; Kann, Alexander; Wang, Yong

    2017-04-01

    Ensemble prediction systems are designed to account for errors or uncertainties in the initial and boundary conditions, imperfect parameterizations, etc. However, due to sampling errors and underestimation of the model errors, these ensemble forecasts tend to be underdispersive, and to lack both reliability and sharpness. To overcome such limitations, statistical postprocessing methods are commonly applied to these forecasts. In this study, a full-distributional spatial post-processing method is applied to short-range precipitation forecasts over Austria using Standardized Anomaly Model Output Statistics (SAMOS). Following Stauffer et al. (2016), observation and forecast fields are transformed into standardized anomalies by subtracting a site-specific climatological mean and dividing by the climatological standard deviation. Due to the need of fitting only a single regression model for the whole domain, the SAMOS framework provides a computationally inexpensive method to create operationally calibrated probabilistic forecasts for any arbitrary location or for all grid points in the domain simultaneously. Taking advantage of the INCA system (Integrated Nowcasting through Comprehensive Analysis), high resolution analyses are used for the computation of the observed climatology and for model training. The INCA system operationally combines station measurements and remote sensing data into real-time objective analysis fields at 1 km-horizontal resolution and 1 h-temporal resolution. The precipitation forecast used in this study is obtained from a limited area model ensemble prediction system also operated by ZAMG. The so called ALADIN-LAEF provides, by applying a multi-physics approach, a 17-member forecast at a horizontal resolution of 10.9 km and a temporal resolution of 1 hour. The performed SAMOS approach statistically combines the in-house developed high resolution analysis and ensemble prediction system. The station-based validation of 6 hour precipitation sums

  13. Investigation on grain refinement and precipitation strengthening applied in high speed wire rod containing vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Da-yong; Xiao, Fu-ren, E-mail: frxiao@ysu.edu.cn; Wang, Bin; Liu, Jia-ling; Liao, Bo, E-mail: cyddjyjs@263.net

    2014-01-13

    To obtain necessary information for the simulation of high speed wire production process, the effect of grain refinement and precipitation strengthening on two high speed wire rod steels with different vanadium and nitrogen contents was investigated by continuous cooling transformation (CCT) characteristics. CCT curves were constructed by the dilatometer test and microscopic observation. Results showed that the formation of intra-granular ferrite (IGF) could refine grain remarkably and accelerate the ferrite transformation. Schedules for high speed wire production process focused on the effect of cooling rate. Ferrite grain was refined by increasing cooling rate and the formation of IGF. The microhardness calculation revealed that the steels were strengthened mostly by a combined effect of grain refinement and precipitation hardening. Degenerated pearlite was observed at lower transformation temperature and the fracture morphology changed from cementite lamellar to nanoscale cementite particle with increasing cooling rate. Based on the analysis above, an optimal schedule was applied and the microstructure and microhardness were improved.

  14. A highly sensitive electrostatic precipitator with no moving parts

    DEFF Research Database (Denmark)

    Teodosić, V.

    1968-01-01

    Cross correlation between a modulated precipitation voltage and the corresponding detector voltage variation gives a signal which is proportional to the fission gas concentration even when the precipitation electrode is not moving, which makes it possible to build a simple unit for fuel leakage...... detection....

  15. Increasing the regional availability of the Standardized Precipitation Index: an operational approach

    Directory of Open Access Journals (Sweden)

    Monica Cristina Meschiatti

    Full Text Available ABSTRACT The need to use a length of rainfall records of at least 30 years to calculate the Standardized Precipitation Index (SPI limits its application in several Drought Early Warning Systems of developing countries. Therefore, in order to increase the number of weather stations in which the SPI may be applied, this study quantified the difference among SPI values derived from calibration periods (CP smaller than 30 years in respect to those computed from the 30-year period of 1985 – 2014 in the State of São Paulo, Brazil (time scales ranging from 1 to 12 months were considered. The correlation, agreement and consistency of SPI values derived from CP ranging from the last 30 to 21 years have been evaluated. The Kolmogorov-Smirnov/Lilliefors test indicated, for all CP, that the 2-parameter gamma distribution may be used to calculate the SPI in the State of São Paulo. The normality test indicated that, even for the period of 1985 – 2014, the normally assumption of the SPI series is not always met. However, it was observed no remarkable difference in the rejection rates of the normality assumption obtained from the different CP. Finally, both absolute mean error and the modified index of agreement indicated a high consistence among SPI values derived from the calibration period of 1991 – 2014 (24 years in respect to those derived from the 30-year period. Accordingly, it is possible to use weather stations with rainfall records starting in 1991 (or earlier to calculate, in operational mode, the SPI in the State of São Paulo.

  16. Precipitation Strengthening by Induction Treatment in High Strength Low Carbon Microalloyed Hot-Rolled Plates

    Science.gov (United States)

    Larzabal, G.; Isasti, N.; Rodriguez-Ibabe, J. M.; Uranga, P.

    2018-03-01

    The use of microalloyed steels in the production of thick plates is expanding due to the possibility of achieving attractive combinations of strength and toughness. As market requirements for high strength plates are increasing and new applications require reduced weight and innovative designs, novel approaches to attaining cost-effective grades are being developed. The mechanism of precipitation strengthening has been widely used in thin strip products, since the optimization of the coiling strategy offers interesting combinations in terms of final properties and microalloying additions. Precipitation strengthening in thick plates, however, is less widespread due to the limitation of interphase precipitation during continuous cooling after hot rolling. With the main objective of exploring the limits of this strengthening mechanism, laboratory thermomechanical simulations that reproduced plate hot rolling mill conditions were performed using low carbon steels microalloyed with Nb, NbMo, and TiMo additions. After continuous cooling to room temperature, a set of heat treatments using fast heating rates were applied simulating the conditions of induction heat treatments. An important increase of both yield and tensile strengths was measured after induction treatment without any important impairment in toughness properties. A significant precipitation hardening is observed in Mo-containing grades under specific heat treatment parameters.

  17. [Effects of increased precipitation on the water use of Nitraira tangutorum at southeast edge of Baddain Jaran Desert in China].

    Science.gov (United States)

    Zhu, Ya-Juan; Lu, Qi; Wu, Bo; Li, Yong-Hua; Yao, Bin; Zhang, Jin-Xin

    2013-01-01

    This paper studied the threshold value of the water use of Nitraria tanturorum shrubs at the southeast edge of Baddain Jiran Desert. From the early May to late September in 2009, an irrigation simulating increased precipitation was conducted once every month. Three ratios of increased precipitation (0, 50% and 100%) were designed, based on the local mean annual precipitation (115 mm). On the 1 day before irrigation and the 1, 3 and 7 days after irrigation in May, July and September, the deltaD in the xylem water of N. tangutorum, the soil water at the depths 10 and 30 cm, and the well water and natural rainfall, and the variations of the soil water content were measured. Under natural condition, the N. tangutorum mainly utilize ground water in May and September, and utilize the soil water at the depths 10 and 30 cm in July. After irrigation, the ground water use rate of the N. tangutorum decreased, while the soil water use rate increased. In the treatment of 100% increased precipitation, the deltaD ratio of the water in N. tangutorum xylem was affected significantly, and the water use of the N. tangutorum in May, July and September increased. In the treatment of 50% increased precipitation, the soil water condition in May and July was improved, but the water use rate had little improvement. Only when the increased precipitation reached 100% of the local mean annual precipitation, could the water use rate of the N. tangutorum have an obvious increase.

  18. High-power high-voltage pulse generator for supplying electrostatic precipitators of dust

    International Nuclear Information System (INIS)

    Radu, A.; Martin, D.

    1992-01-01

    The study and development of an experimental high voltage generator specialized in the supply of electrostatic precipitators are presented. The main parameters of the pulse generator are: U = -30 kV, I = 8.8 A, τ = 120μs, f r = 150 Hz. The pulse generator was tested on a laboratory electrostatic precipitator with nominal capacitance C = 25 nF, biased at -40 kV by means of a separate high voltage rectifier. The experimental results will be used for the creation of a more powerful pulse generator, a prototype for the supply of a real industrial electrostatic precipitator: U = -50 kV, I = 313 A, τ = 100μs, f r = 300 Hz, C = 100 nF. (Author)

  19. High Heels Increase Women's Attractiveness.

    Science.gov (United States)

    Guéguen, Nicolas

    2015-11-01

    Research has found that the appearance of women's apparel helps increase their attractiveness as rated by men and that men care more about physical features in potential opposite-sex mates. However, the effect of sartorial appearance has received little interest from scientists. In a series of studies, the length of women's shoe heels was examined. A woman confederate wearing black shoes with 0, 5, or 9 cm heels asked men for help in various circumstances. In Study 1, she asked men to respond to a short survey on gender equality. In Study 2, the confederate asked men and women to participate in a survey on local food habit consumption. In Study 3, men and women in the street were observed while walking in back of the female confederate who dropped a glove apparently unaware of her loss. It was found that men's helping behavior increased as soon as heel length increased. However, heel length had no effect on women's helping behavior. It was also found that men spontaneously approached women more quickly when they wore high-heeled shoes (Study 4). Change in gait, foot-size judgment, and misattribution of sexiness and sexual intent were used as possible explanations.

  20. A DLTS study of the evolution of oxygen precipitates in Si at high temperature and high pressure

    International Nuclear Information System (INIS)

    Antonova, I.V.; Popov, V.P.; Fedina, L.I.; Shaimeev, S.S.; Misiuk, A.

    1996-01-01

    The effect of high hydrostatic pressure on the dissolution of oxygen precipitates introduced beforehand into Si at temperatures of 920-1000 K (over period of 96 h) is investigated by the DLTS method. A measurement procedure, based on the formation of electrically active complexes (interstitial oxygen atom-vacancy) during electron irradiation of the samples, is proposed. It is shown that the precipitates do not decompose when point defects are introduced at room temperature. As the treatment temperature increases (to 1220-1650 K), for the same values of the hydrostatic pressure (up to 1.3 GPa) the intensity of the decomposition of oxygen precipitates increases and at 1650 K they are completely dissolved. Study of the decomposition kinetics showed that hydrostatic pressure raises the limit of solubility of the oxygen atoms Oi and slows down their diffusion. It is determined that the diffusion activation energy Ea, just as the preexponential factor D0, in the expression for the diffusion decrease with increasing hydrostatic pressure, resulting in a lower diffusion. Possible mechanisms for the effect of hydrostatic pressure on oxygen diffusion near a precipitate are discussed

  1. Interactive effects of warming and increased precipitation on community structure and composition in an annual forb dominated desert steppe.

    Directory of Open Access Journals (Sweden)

    Yanhui Hou

    Full Text Available To better understand how warming, increased precipitation and their interactions influence community structure and composition, a field experiment simulating hydrothermal interactions was conducted at an annual forb dominated desert steppe in northern China over 2 years. Increased precipitation increased species richness while warming significantly decreased species richness, and their effects were additive rather than interactive. Although interannual variations in weather conditions may have a major affect on plant community composition on short term experiments, warming and precipitation treatments affected individual species and functional group composition. Warming caused C4 grasses such as Cleistogenes squarrosa to increase while increased precipitation caused the proportions of non-perennial C3 plants like Artemisia capillaris to decrease and perennial C4 plants to increase.

  2. Effect of prior deformation on microstructural development and Laves phase precipitation in high-chromium stainless steel.

    Science.gov (United States)

    Hsiao, Z-W; Chen, D; Kuo, J-C; Lin, D-Y

    2017-04-01

    This study investigated the influence of deformation on precipitation behaviour and microstructure change during annealing. Here, the prior deformation of high-chromium stainless steel was tensile deformation of 3%, 6% and 10%, and the specimens were then annealed at 700˚C for 10 h. The specimens were subsequently analyzed using backscattered electron image and electron backscattering diffraction measurements with SEM. Compared with the deformation microstructure, the grains revealed no preferred orientation. The precipitates of TiN and NbC were formed homogenously in the grain interior and at grain boundaries after annealing. Fine Laves phase precipitates were observed in grains and along subgrain boundaries as the deformation increased. Furthermore, the volume fraction of Laves phase increased, but the average particle diameter of precipitate was reduced as the deformation increased. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  3. Studies on the oxygen precipitation in highly boron doped silicon; Untersuchungen zur Sauerstoffausscheidung in hoch bordotiertem Silicium

    Energy Technology Data Exchange (ETDEWEB)

    Zschorsch, Markus

    2007-12-14

    The aim of this thesis was the getting of new knowledge on the elucidation of the oxygen precipitation in highly doped silicon. In the study of the early phases of the oxygen precipitation boron-oxygen complexes and their kinetics could be indirectly detected. These arise already during the cooling of the crystal and can be destroyed by subsequent temperature processes. The formation of the here as BO assumed species during the cooling after the silicon crystal fabrication could be numerically reproduced. Furthermore the study of early precipitation phases by means of neutron small angle scattering a maximum of the oxygen precipitation at {rho}=9 m{omega}cm. It could be shown that the decreasing of this at increasing boron concentration can be most probably reduced to boron precipitations. Furthermore it could be shown that after a tempering time of 24 hours at 700 C in silicon with {rho}=9 m{omega}cm platelet-shaped precipitates form. By the study of the precipitate growth could be shown that also in this phase the oxygen precipitation in silicon is strongest with a specific resistance of {rho}=9 m{omega}cm. By means of FTIR spectroscopy a new absorption band at a wave number of 1038 cm{sup -1} was found, which could be assigned to a boron species. By different experiments it is considered as probable that at this species it deals with BI respectively B{sub 2}I complexes.

  4. Increased temperature and altered summer precipitation have differential effects on biological soil crusts in a dryland ecosystem

    Science.gov (United States)

    Johnson, Shannon L.; Kuske, Cheryl R.; Carney, Travis D.; Housman, David C.; Gallegos-Graves, La Verne; Belnap, Jayne

    2012-01-01

    Biological soil crusts (biocrusts) are common and ecologically important members of dryland ecosystems worldwide, where they stabilize soil surfaces and contribute newly fixed C and N to soils. To test the impacts of predicted climate change scenarios on biocrusts in a dryland ecosystem, the effects of a 2–3 °C increase in soil temperature and an increased frequency of smaller summer precipitation events were examined in a large, replicated field study conducted in the cold desert of the Colorado Plateau, USA. Surface soil biomass (DNA concentration), photosynthetically active cyanobacterial biomass (chlorophyll a concentration), cyanobacterial abundance (quantitative PCR assay), and bacterial community composition (16S rRNA gene sequencing) were monitored seasonally over 2 years. Soil microbial biomass and bacterial community composition were highly stratified between the 0–2 cm depth biocrusts and 5–10 cm depth soil beneath the biocrusts. The increase in temperature did not have a detectable effect on any of the measured parameters over 2 years. However, after the second summer of altered summer precipitation pattern, significant declines occurred in the surface soil biomass (avg. DNA concentration declined 38%), photosynthetic cyanobacterial biomass (avg. chlorophyll a concentration declined 78%), cyanobacterial abundance (avg. gene copies g−1 soil declined 95%), and proportion of Cyanobacteria in the biocrust bacterial community (avg. representation in sequence libraries declined 85%). Biocrusts are important contributors to soil stability, soil C and N stores, and plant performance, and the loss or reduction of biocrusts under an altered precipitation pattern associated with climate change could contribute significantly to lower soil fertility and increased erosion and dust production in dryland ecosystems at a regional scale.

  5. An Ultra-high Resolution Synthetic Precipitation Data for Ungauged Sites

    Science.gov (United States)

    Kim, Hong-Joong; Choi, Kyung-Min; Oh, Jai-Ho

    2018-05-01

    Despite the enormous damage caused by record heavy rainfall, the amount of precipitation in areas without observation points cannot be known precisely. One way to overcome these difficulties is to estimate meteorological data at ungauged sites. In this study, we have used observation data over Seoul city to calculate high-resolution (250-meter resolution) synthetic precipitation over a 10-year (2005-2014) period. Furthermore, three cases are analyzed by evaluating the rainfall intensity and performing statistical analysis over the 10-year period. In the case where the typhoon "Meari" passed to the west coast during 28-30 June 2011, the Pearson correlation coefficient was 0.93 for seven validation points, which implies that the temporal correlation between the observed precipitation and synthetic precipitation was very good. It can be confirmed that the time series of observation and synthetic precipitation in the period almost completely matches the observed rainfall. On June 28-29, 2011, the estimation of 10 to 30 mm h-1 of continuous strong precipitation was correct. In addition, it is shown that the synthetic precipitation closely follows the observed precipitation for all three cases. Statistical analysis of 10 years of data reveals a very high correlation coefficient between synthetic precipitation and observed rainfall (0.86). Thus, synthetic precipitation data show good agreement with the observations. Therefore, the 250-m resolution synthetic precipitation amount calculated in this study is useful as basic data in weather applications, such as urban flood detection.

  6. Phase transformation and precipitation in aged Ti-Ni-Hf high-temperature shape memory alloys

    International Nuclear Information System (INIS)

    Meng, X.L.; Cai, W.; Zheng, Y.F.; Zhao, L.C.

    2006-01-01

    More attention has been paid to ternary Ti-Ni-Hf high-temperature shape memory alloys (SMAs) due to their high phase transformation temperatures, good thermal stability and low cost. However, the Ti-Ni-Hf alloys have been found to have low ductility and only about 3% shape memory effect and these have hampered their applications. It is well known that there are three methods to improve the shape memory properties of high-temperature SMAs: (a) cold rolling + annealing; (b) adding another element to the alloy; (c) aging. These methods are not suitable to improve the properties of Ti-Ni-Hf alloys. In this paper, a method of conditioning Ni-rich Ti-Ni-Hf alloys as high-temperature SMAs by aging is presented. For Ni-rich Ti 80-x Ni x Hf 20 alloys (numbers indicate at.%) the phase transformation temperatures are on average increased by more than 100 K by aging at 823 K for 2 h. Especially for those alloys with Ni contents less than 50.6 at.%, the martensitic transformation start temperatures (M s ) are higher than 473 K after aging. Transmission electron microscopy shows the presence of (Ti + Hf) 3 Ni 4 precipitates after aging. Compared with the precipitation of Ti 3 Ni 4 particles in Ni-rich Ti-Ni alloys, the precipitation of (Ti + Hf) 3 Ni 4 particles in Ni-rich Ti-Ni-Hf alloys needs higher temperatures and longer times

  7. Shifts in pore connectivity from precipitation versus groundwater rewetting increases soil carbon loss after drought

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Ashly P.; Bond-Lamberty, Benjamin; Benscoter, Brian W.; Tfaily, Malak M.; Hinkle, Ross; Liu, Chongxuan; Bailey, Vanessa L.

    2017-11-06

    Droughts and other extreme precipitation events are predicted to increase in intensity, duration and extent, with uncertain implications for terrestrial carbon (C) sequestration. Soil wetting from above (precipitation) results in a characteristically different pattern of pore-filling than wetting from below (groundwater), with larger, well-connected pores filling before finer pore spaces, unlike groundwater rise in which capillary forces saturate the finest pores first. Here we demonstrate that pore-scale wetting patterns interact with antecedent soil moisture conditions to alter pore-, core- and field-scale C dynamics. Drought legacy and wetting direction are perhaps more important determinants of short-term C mineralization than current soil moisture content in these soils. Our results highlight that microbial access to C is not solely limited by physical protection, but also by drought or wetting-induced shifts in hydrologic connectivity. We argue that models should treat soil moisture within a three-dimensional framework emphasizing hydrologic conduits for C and resource diffusion.

  8. High-strength wrought magnesium alloy with dense nano-scale spherical precipitate

    Institute of Scientific and Technical Information of China (English)

    YU WenBin; CHEN ZhiQian; CHENG NanPu; GAN BingTai; HE Hong; LI XueLian; HU JinZhu

    2007-01-01

    This paper reported the influences of Yb addition on the precipitate and mechanical properties of wrought magnesium alloy ZK60. The ingots of ZK60-1.78Yb (wt%,0.26 at%) alloys were cast using permanent mould and extruded at 370℃. By means of TEM and HRTEM,it was observed that Yb affected the precipitate and precipitation of ZK60-1.78Yb alloys significantly. Dynamic precipitation occurred in the as-extruded alloy and spherical nano-scale precipitate with high density and homogeneity exhibited in the aged alloys. The precipitate particles were about 5-20 nm in diameter,10-30 nm in average space length. The tensile test results showed that the ZK60-1.78Yb alloy had excellent precipitation strengthening response with the maximum tensile strength 417.5 MPa at ambient temperature.

  9. Hydrological Applications of a High-Resolution Radar Precipitation Data Base for Sweden

    Science.gov (United States)

    Olsson, Jonas; Berg, Peter; Norin, Lars; Simonsson, Lennart

    2017-04-01

    There is an increasing need for high-resolution observations of precipitation on local, regional, national and even continental level. Urbanization and other environmental changes often make societies more vulnerable to intense short-duration rainfalls (cloudbursts) and their consequences in terms of e.g. flooding and landslides. Impact and forecasting models of these hazards put very high demands on the rainfall input in terms of both resolution and accuracy. Weather radar systems obviously have a great potential in this context, but also limitations with respect to e.g. conversion algorithms and various error sources that may have a significant impact on the subsequent hydrological modelling. In Sweden, the national weather radar network has been in operation for nearly three decades, but until recently the hydrological applications have been very limited. This is mainly because of difficulties in managing the different errors and biases in the radar precipitation product, which made it hard to demonstrate any distinct added value as compared with gauge-based precipitation products. In the last years, however, in light of distinct progress in developing error correction procedures, substantial efforts have been made to develop a national gauge-adjusted radar precipitation product - HIPRAD (High-Resolution Precipitation from Gauge-Adjusted Weather Radar). In HIPRAD, the original radar precipitation data are scaled to match the monthly accumulations in a national grid (termed PTHBV) created by optimal interpolation of corrected daily gauge observations, with the intention to attain both a high spatio-temporal resolution and accurate long-term accumulations. At present, HIPRAD covers the period 2000-present with resolutions 15 min and 2×2 km2. A key motivation behind the development of HIPRAD is the intention to increase the temporal resolution in the national flood forecasting system from 1 day to 1 hour. Whereas a daily time step is sufficient to describe the

  10. Effect of Various Retrogression Regimes on Aging Behavior and Precipitates Characterization of a High Zn-Containing Al-Zn-Mg-Cu Alloy

    Science.gov (United States)

    Wen, Kai; Xiong, Baiqing; Zhang, Yongan; Li, Zhihui; Li, Xiwu; Huang, Shuhui; Yan, Lizhen; Yan, Hongwei; Liu, Hongwei

    2018-03-01

    In the present work, the influence of various retrogression treatments on hardness, electrical conductivity and mechanical properties of a high Zn-containing Al-Zn-Mg-Cu alloy is investigated and several retrogression regimes subjected to a same strength level are proposed. The precipitates are qualitatively investigated by means of transmission electron microscopy (TEM) and high-resolution transmission electron microscopy techniques. Based on the matrix precipitate observations, the distributions of precipitate size and nearest inter-precipitate distance are extracted from bright-field TEM images projected along Al orientation with the aid of an imaging analysis and an arithmetic method. The results show that GP zones and η' precipitates are the major precipitates and the precipitate size and its distribution range continuously enlarge with the retrogression regime expands to an extent of high temperature. The nearest inter-precipitate distance ranges obtained are quite the same and the average distance of nearest inter-precipitates show a slight increase. The influence of precipitates on mechanical properties is discussed through the interaction relationship between precipitates and dislocations.

  11. Effect of Various Retrogression Regimes on Aging Behavior and Precipitates Characterization of a High Zn-Containing Al-Zn-Mg-Cu Alloy

    Science.gov (United States)

    Wen, Kai; Xiong, Baiqing; Zhang, Yongan; Li, Zhihui; Li, Xiwu; Huang, Shuhui; Yan, Lizhen; Yan, Hongwei; Liu, Hongwei

    2018-05-01

    In the present work, the influence of various retrogression treatments on hardness, electrical conductivity and mechanical properties of a high Zn-containing Al-Zn-Mg-Cu alloy is investigated and several retrogression regimes subjected to a same strength level are proposed. The precipitates are qualitatively investigated by means of transmission electron microscopy (TEM) and high-resolution transmission electron microscopy techniques. Based on the matrix precipitate observations, the distributions of precipitate size and nearest inter-precipitate distance are extracted from bright-field TEM images projected along Al orientation with the aid of an imaging analysis and an arithmetic method. The results show that GP zones and η' precipitates are the major precipitates and the precipitate size and its distribution range continuously enlarge with the retrogression regime expands to an extent of high temperature. The nearest inter-precipitate distance ranges obtained are quite the same and the average distance of nearest inter-precipitates show a slight increase. The influence of precipitates on mechanical properties is discussed through the interaction relationship between precipitates and dislocations.

  12. Dissimilarity of Ant Communities Increases with Precipitation, but not Reduced Land-Use Intensity, in Indonesian Cacao Agroforestry

    Directory of Open Access Journals (Sweden)

    Damayanti Buchori

    2013-01-01

    Full Text Available Land-use degradation and climate change are well-known drivers of biodiversity loss, but little information is available about their potential interaction. Here, we focus on the effects of land-use and precipitation on ant diversity in cacao agroforestry. In Central Sulawesi, Indonesia, we selected 16 cacao agroforestry plots with a shaded vs. unshaded plot in each of eight villages differing in precipitation (1032–2051 mm annual rainfall. On each plot, 10 cacao trees with similar size and age (7–10 years were selected for hand collection of ants on each cacao tree and the soil surface. In total, we found 80 ant species belonging to five subfamilies. Land-use intensification (removal of shade trees and precipitation had no effect on species richness of ants per cacao tree (alpha diversity and, in an additive partitioning approach, within-plot beta diversity. However, higher precipitation (but not shade significantly increased ant species dissimilarity across cacao trees within a plot, with ant species showing contrasting responses to precipitation. Reduced precipitation causing drought stress appeared to contribute to convergence of ant community structure, presumably via reduced heterogeneity in cacao tree growth. In conclusion, reduced precipitation greatly influenced ant community dissimilarity and appeared to be more important for ant community structure than land-use intensification.

  13. Pretreating dogwood seedlings with simulated acidic precipitation increases dogwood anthracnose symptoms in greenhouse-laboratory trials

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, R.L.; Knighten, J. (USDA Forest Service, Resistance Screening Center, Asheville, NC (United States)); Berrange, P.; Lawton, K.A. (USDA Forest Service, Center for Forest Environmental Studies, Dry Branch, GA (United States)); Britton, K.O. (USDA Forest Service, Southeastern Forest Experiment Station, Athens, GA (United States))

    1993-01-01

    Dogwood anthracnose is the most damaging disease of flowering dogwood (Cornus florida L.) in a large part of the tree's natural range. It is caused by Discula destructiva infection. Previous attempts to inoculate C. florida to produce anthracnose symptoms have met with limited success except when the leaves were pretreated with acidic water, suggesting that acidic precipitation may predispose dogwoods to the disease. This hypothesis was tested in two greenhouse-laboratory studies in which year-old C. florida seedlings were randomly assigned to four treatments of simulated rain (pH 2.5, 3.5, 4.5, and 5.5) in 1989 and 1990. After 10 applications over a 42-d period, the seedlings were moved to a temperature-controlled laboratory, placed in plastic bags, humidified, and sprayed with a spore suspension of five D. destructiva isolates. About 30 d layter, the seedlings were examined for the percentage of leaves exhibiting anthracnose symptoms and disease severity on affected leaves. Both trials showed that as the acidity of the simulated rain increased, the incidence and severity of anthracnose leaf symptoms increased. The 1989 study included a soil lime treatment that showed the same trend but the overall occurrence and severity of symptoms was higher. 17 refs., 5 tabs.

  14. An appraisal of precipitation distribution in the high-altitude catchments of the Indus basin.

    Science.gov (United States)

    Dahri, Zakir Hussain; Ludwig, Fulco; Moors, Eddy; Ahmad, Bashir; Khan, Asif; Kabat, Pavel

    2016-04-01

    Scarcity of in-situ observations coupled with high orographic influences has prevented a comprehensive assessment of precipitation distribution in the high-altitude catchments of Indus basin. Available data are generally fragmented and scattered with different organizations and mostly cover the valleys. Here, we combine most of the available station data with the indirect precipitation estimates at the accumulation zones of major glaciers to analyse altitudinal dependency of precipitation in the high-altitude Indus basin. The available observations signified the importance of orography in each sub-hydrological basin but could not infer an accurate distribution of precipitation with altitude. We used Kriging with External Drift (KED) interpolation scheme with elevation as a predictor to appraise spatiotemporal distribution of mean monthly, seasonal and annual precipitation for the period of 1998-2012. The KED-based annual precipitation estimates are verified by the corresponding basin-wide observed specific runoffs, which show good agreement. In contrast to earlier studies, our estimates reveal substantially higher precipitation in most of the sub-basins indicating two distinct rainfall maxima; 1st along southern and lower most slopes of Chenab, Jhelum, Indus main and Swat basins, and 2nd around north-west corner of Shyok basin in the central Karakoram. The study demonstrated that the selected gridded precipitation products covering this region are prone to significant errors. In terms of quantitative estimates, ERA-Interim is relatively close to the observations followed by WFDEI and TRMM, while APHRODITE gives highly underestimated precipitation estimates in the study area. Basin-wide seasonal and annual correction factors introduced for each gridded dataset can be useful for lumped hydrological modelling studies, while the estimated precipitation distribution can serve as a basis for bias correction of any gridded precipitation products for the study area

  15. High-Resolution Modeling of ENSO-Induced Precipitation in the Tropical Andes: Implications for Proxy Interpretation.

    Science.gov (United States)

    Kiefer, J.; Karamperidou, C.

    2017-12-01

    Clastic sediment flux into high-elevation Andean lakes is controlled by glacial processes and soil erosion caused by high precipitation events, making these lakes suitable archives of past climate. To wit, sediment records from Laguna Pallcacocha in Ecuador have been interpreted as proxies of ENSO variability, owing to increased precipitation in the greater region during El Niño events. However, the location of the lake's watershed, the presence of glaciers, and the different impacts of ENSO on precipitation in the eastern vs western Andes have challenged the suitability of the Pallcacocha record as an ENSO proxy. Here, we employ WRF, a high-resolution regional mesoscale weather prediction model, to investigate the circulation dynamics, sources of moisture, and resulting precipitation response in the L. Pallcacocha region during different flavors of El Niño and La Niña events, and in the presence or absence of ice caps. In patricular, we investigate Eastern Pacific (EP), Central Pacific (CP), coastal El Niño, and La Niña events. We validate the model simulations against spatially interpolated station measurements and reanalysis data. We find that during EP events, moisture is primarily advected from the Pacific, whereas during CP events, moisture primarily originates from the Atlantic. More moisture is available during EP events, which implies higher precipitation rates. Furthermore, we find that precipitation during EP events is mostly non-convective in contrast to primarily convective precipitation during CP events. Finally, a synthesis of the sedimentary record and the EP:CP ratio of accumulated precipitation and specific humidity in the L. Pallcacocha region allows us to assess whether past changes in the relative frequency of the two ENSO flavors may have been recorded in paleoclimate archives in this region.

  16. PDF added value of a high resolution climate simulation for precipitation

    Science.gov (United States)

    Soares, Pedro M. M.; Cardoso, Rita M.

    2015-04-01

    General Circulation Models (GCMs) are models suitable to study the global atmospheric system, its evolution and response to changes in external forcing, namely to increasing emissions of CO2. However, the resolution of GCMs, of the order of 1o, is not sufficient to reproduce finer scale features of the atmospheric flow related to complex topography, coastal processes and boundary layer processes, and higher resolution models are needed to describe observed weather and climate. The latter are known as Regional Climate Models (RCMs) and are widely used to downscale GCMs results for many regions of the globe and are able to capture physically consistent regional and local circulations. Most of the RCMs evaluations rely on the comparison of its results with observations, either from weather stations networks or regular gridded datasets, revealing the ability of RCMs to describe local climatic properties, and assuming most of the times its higher performance in comparison with the forcing GCMs. The additional climatic details given by RCMs when compared with the results of the driving models is usually named as added value, and it's evaluation is still scarce and controversial in the literuature. Recently, some studies have proposed different methodologies to different applications and processes to characterize the added value of specific RCMs. A number of examples reveal that some RCMs do add value to GCMs in some properties or regions, and also the opposite, elighnening that RCMs may add value to GCM resuls, but improvements depend basically on the type of application, model setup, atmospheric property and location. The precipitation can be characterized by histograms of daily precipitation, or also known as probability density functions (PDFs). There are different strategies to evaluate the quality of both GCMs and RCMs in describing the precipitation PDFs when compared to observations. Here, we present a new method to measure the PDF added value obtained from

  17. High-resolution precipitation database for the last two centuries in Italy: climatologies and anomalies

    Science.gov (United States)

    Crespi, Alice; Brunetti, Michele; Maugeri, Maurizio

    2017-04-01

    The availability of gridded high-resolution spatial climatologies and corresponding secular records has acquired an increasing importance in the recent years both to research purposes and as decision-support tools in the management of natural resources and economical activities. High-resolution monthly precipitation climatologies for Italy were computed by gridding on a 30-arc-second-resolution Digital Elevation Model (DEM) the precipitation normals (1961-1990) obtained from a quality-controlled dataset of about 6200 stations covering the Italian surface and part of the Northern neighbouring regions. Starting from the assumption that the precipitation distribution is strongly influenced by orography, especially elevation, a local weighted linear regression (LWLR) of precipitation versus elevation was performed at each DEM cell. The regression coefficients for each cell were estimated by selecting the stations with the highest weights in which the distances and the level of similarity between the station cells and the considered grid cell, in terms of orographic features, are taken into account. An optimisation procedure was then set up in order to define, for each month and for each grid cell, the most suitable decreasing coefficients for the weighting factors which enter in the LWLR scheme. The model was validated by the comparison with the results provided by inverse distance weighting (IDW) applied both to station normals and to the residuals of a global regression of station normals versus elevation. In both cases, the LWLR leave-one-out reconstructions show the best agreement with the observed station normals, especially when considering specific station clusters (high elevation sites for example). After producing the high-resolution precipitation climatological field, the temporal component on the high-resolution grid was obtained by following the anomaly method. It is based on the assumption that the spatio-temporal structure of the signal of a

  18. Precipitation characteristic of high strength steels microalloyed with titanium produced by compact strip production

    Institute of Scientific and Technical Information of China (English)

    Jian Zhou; Yonglin Kang; Xinping Mao

    2008-01-01

    Transmission electron microscopy (TEM) and physics-chemical phase analysis were employed to investigate the precipitates in high strength steels microalloyed with Ti produced by compact strip production (CSP). It was seen that precipitates in Ti mieroalloyed steels mainly included TiN, Ti4C2S2, and TiC. The size of TiN particles varied from 50 to 500 nm, and they could precipitate during or before soaking. The Ti4C2S>2 with the size of 40-100 nm might precipitate before rolling, and the TiC particles with the size of 5-50 nm precipitated heterogeneously. High Ti content would lead to the presence of bigger TiC particles that precipitated in austenite, and by contrast, TiC particles that precipitated in ferrite and the transformation of austenite to ferrite was smaller. They were less than 30 nm and mainly responsible for precipitate strengthening. It should be noted that the TiC particles in higher Ti content were generally smaller than those in the steel with a lower Ti content.

  19. Fast high-temperature consolidation of Oxide-Dispersion Strengthened (ODS) steels: process, microstructure, precipitation, properties

    International Nuclear Information System (INIS)

    Boulnat, Xavier

    2014-01-01

    This work aims to lighten the understanding of the behavior of a class of metallic materials called Oxide-Dispersion Strengthened (ODS) ferritic steels. ODS steels are produced by powder metallurgy with various steps including atomization, mechanical alloying and high-temperature consolidation. The consolidation involves the formation of nanoparticles in the steel and various evolutions of the microstructure of the material that are not fully understood. In this thesis, a novel consolidation technique assisted by electric field called 'Spark Plasma Sintering' (SPS) or 'Field-Assisted Sintering Technique' (FAST) was assessed. Excellent mechanical properties were obtained by SPS, comparable to those of conventional hot isostatic pressed (HIP) materials but with much shorter processing time. Also, a broad range of microstructures and thus of tensile strength and ductility were obtained by performing SPS on either milled or atomized powder at different temperatures. However, SPS consolidation failed to avoid heterogeneous microstructure composed of ultrafine-grained regions surrounded by micron grains despite of the rapid consolidation kinetics. A multi-scale characterization allowed to understand and model the evolution of this complex microstructure. An analytical evaluation of the contributing mechanisms can explain the appearance of the complex grain structure and its thermal stability during further heat treatments. Inhomogeneous distribution of plastic deformation in the powder is argued to be the major cause of heterogeneous recrystallization and further grain growth during hot consolidation. Even if increasing the solute content of yttrium, titanium and oxygen does not impede abnormal growth, it permits to control the fraction and the size of the retained ultrafine grains, which is a key-factor to tailor the mechanical properties. Since precipitation through grain boundary pinning plays a significant role on grain growth, a careful

  20. Verification of high resolution simulation of precipitation and wind in Portugal

    Science.gov (United States)

    Menezes, Isilda; Pereira, Mário; Moreira, Demerval; Carvalheiro, Luís; Bugalho, Lourdes; Corte-Real, João

    2017-04-01

    Demand of energy and freshwater continues to grow as the global population and demands increase. Precipitation feed the freshwater ecosystems which provides a wealth of goods and services for society and river flow to sustain native species and natural ecosystem functions. The adoption of the wind and hydro-electric power supplies will sustain energy demands/services without restricting the economic growth and accelerated policies scenarios. However, the international meteorological observation network is not sufficiently dense to directly support high resolution climatic research. In this sense, coupled global and regional atmospheric models constitute the most appropriate physical and numerical tool for weather forecasting and downscaling in high resolution grids with the capacity to solve problems resulting from the lack of observed data and measuring errors. Thus, this study aims to calibrate and validate of the WRF regional model from precipitation and wind fields simulation, in high spatial resolution grid cover in Portugal. The simulations were performed in two-way nesting with three grids of increasing resolution (60 km, 20 km and 5 km) and the model performance assessed for the summer and winter months (January and July), using input variables from two different reanalyses and forecasted databases (ERA-Interim and NCEP-FNL) and different forcing schemes. The verification procedure included: (i) the use of several statistics error estimators, correlation based measures and relative errors descriptors; and, (ii) an observed dataset composed by time series of hourly precipitation, wind speed and direction provided by the Portuguese meteorological institute for a comprehensive set of weather stations. Main results suggested the good ability of the WRF to: (i) reproduce the spatial patterns of the mean and total observed fields; (ii) with relatively small values of bias and other errors; and, (iii) and good temporal correlation. These findings are in good

  1. Oak Forest Responses to Episodic-Seasonal-Drought, Chronic Multi-year Precipitation Change and Acute Drought Manipulations in a Region With Deep Soils and High Precipitation

    Science.gov (United States)

    Hanson, Paul J.; Wullschleger, Stan D.; Todd, Donald E.; Auge, Robert M.; Froberg, Mats; Johnson, Dale W.

    2010-05-01

    drying, but no change in mineral soil carbon pools attributable to changing precipitation. Measured changes in nitrogen and other element pools suggested that long term immobilization of elements with chronic drying would lead to reduced growth, but that deep rooting access to the key base cations would moderate such effects by providing a source of minerals to be cycled in near surface soils. Cumulative changes in canopy foliar production were evident over time showing sustained or even increased production with chronic drying. This unexpected response is hypothesized to result from the retention of nutrients in highly-rooted surface horizons made available for plant uptake during spring mineralization.

  2. The effect of Si on precipitation in Al–Cu–Mg alloy with a high Cu/Mg ratio

    International Nuclear Information System (INIS)

    Liu, L.; Chen, J.H.; Wang, S.B.; Liu, C.H.; Yang, S.S.; Wu, C.L.

    2014-01-01

    The precipitations in an Al–5.0Cu–0.3Mg (wt%) alloy and an Al–5.0Cu–0.3Mg–0.3Si (wt%) alloy have been systematically investigated by high-angle annular dark-field scanning transmission electron microscopy. The results are compared to clarify the effect of Si addition. The nucleation and growth process of θ′ (Al 2 Cu) phase in Si-containing alloy during isothermal ageing at 180 °C is revealed in detail. The formation of Q″-type precipitates, on which the θ′ precursors nucleate heterogeneously, contributes to the considerable increase in the ageing kinetics and higher strength at the early ageing stage. The thickening of the θ′ precipitate is largely confined due to the rather small size of fine Q″-type precipitate. As a result, a large proportion of θ′ phase precipitates possess a specific thickness of 2c θ′ and change slightly during the entire observed duration of ageing. The θ′ growth mechanism distinct from the Al–Cu–Mg alloy finally leads to a refined θ′ morphology regarding the thickness and aspect ratio (diameter/thickness). As is counterintuitive, the θ′ precipitate thickness distribution is demonstrated to have little effect on the mechanical property steadiness at the late ageing stage of the Al–Cu–Mg–(Si) alloys

  3. Numerical simulation of Cr2N age-precipitation in high nitrogen stainless steels

    International Nuclear Information System (INIS)

    Dai, Q.X.; Yuan, Z.Z.; Luo, X.M.; Cheng, X.N.

    2004-01-01

    At the temperature raging from 700 to 950 deg. C, the Cr 2 N age-precipitation in high nitrogen austenitic stainless steels Fe24Mn18Cr3Ni0.62N was investigated in this paper. A qualitative mathematical model of Cr 2 N age-precipitation, ln t S = f (Me,1/T), was established based on the thermodynamics and kinetics and phase transformation theories. Satisfactory results were obtained by means of the test of artificial neural network. This mathematical model can be applied to the calculation design and predication of Cr 2 N age-precipitation in high nitrogen stainless steels

  4. Precipitation behavior of carbides in high-carbon martensitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Qin-tian; Li, Jing; Shi, Cheng-bin; Yu, Wen-tao; Shi, Chang-min [University of Science and Technology, Beijing (China). State Key Laboratory of Advanced Metallurgy; Li, Ji-hui [Yang Jiang Shi Ba Zi Group Co., Ltd, Guangdong (China)

    2017-01-15

    A fundamental study on the precipitation behavior of carbides was carried out. Thermo-calc software, scanning electron microscopy, electron probe microanalysis, transmission electron microscopy, X-ray diffractometry and high-temperature confocal laser scanning microscopy were used to study the precipitation and transformation behaviors of carbides. Carbide precipitation was of a specific order. Primary carbides (M7C3) tended to be generated from liquid steel when the solid fraction reached 84 mol.%. Secondary carbides (M7C3) precipitated from austenite and can hardly transformed into M23C6 carbides with decreasing temperature in air. Primary carbides hardly changed once they were generated, whereas secondary carbides were sensitive to heat treatment and thermal deformation. Carbide precipitation had a certain effect on steel-matrix phase transitions. The segregation ability of carbon in liquid steel was 4.6 times greater that of chromium. A new method for controlling primary carbides is proposed.

  5. The role of the cold Okhotsk Sea in strengthening of the Pacific subtropical high and Baiu precipitation

    Science.gov (United States)

    Kawasaki, K.; Tachibana, Y.; Nakamura, T.; Yamazaki, K.; Kodera, K.

    2016-12-01

    It is commonly known that the formation of a stationery precipitation zone in association with the Baiu front is influenced by the existence of the warm Tibetan Plateau. Some GCM studies in which the Tibetan Plateau is removed pointed out that without the Tibetan Plateau, the Baiu front wound not appear. The cold Okhotsk Sea, which is located to the north of Japan, is also important in forming cold air for the Bai front. This study focused on the role of the Okhotsk Sea in the formation of the Baiu front by using an atmospheric GCM. One GCM is executed without the Okhotsk Sea, in which was changed to an eastern part of the Eurasian continent as if the Okhotsk Sea was totally landfilled (land run). The other (sea run) is a control run under the boundary condition of climatic seasonal changes of the SST over the globe. The comparison of the land run with the sea run showed that precipitation over Japan would weaken in the Baiu season without the Okhotsk Sea, indicating that the existence of the Okhotsk Sea has an impact on the increase in precipitation. The precipitation increase in the sea run is directly accounted by the strengthening of southeast wind in association with the strengthening of the subtropical high located over the Pacific Ocean (Fig. 1). The westerly jet, which is located at the northern part of the subtropical high, was also accelerated in the sea run. The subtropical high in association with the accelerated jet was strengthened by meridional atmospheric thermal gradient caused by underlying cold Okhotsk Sea and the warm Pacific Ocean. The strengthened thermal gradient also activated the storm track that extends zonally over the Okhotsk Sea, and the activated storm track further strengthened the jet and subtropical high by wave-mean flow feedback. This feedback loop could further strengthen the Baiu precipitation. In consequence, the Okhotsk plays a significant role in the strengthening the subtropical high and its associated Baiu precipitation.

  6. Can small island mountains provide relief from the Subtropical Precipitation Decline? Simulating future precipitation regimes for small island nations using high resolution Regional Climate Models.

    Science.gov (United States)

    Bowden, J.; Terando, A. J.; Misra, V.; Wootten, A.

    2017-12-01

    Small island nations are vulnerable to changes in the hydrologic cycle because of their limited water resources. This risk to water security is likely even higher in sub-tropical regions where anthropogenic forcing of the climate system is expected to lead to a drier future (the so-called `dry-get-drier' pattern). However, high-resolution numerical modeling experiments have also shown an enhancement of existing orographically-influenced precipitation patterns on islands with steep topography, potentially mitigating subtropical drying on windward mountain sides. Here we explore the robustness of the near-term (25-45 years) subtropical precipitation decline (SPD) across two island groupings in the Caribbean, Puerto Rico and the U.S. Virgin Islands. These islands, forming the boundary between the Greater and Lesser Antilles, significantly differ in size, topographic relief, and orientation to prevailing winds. Two 2-km horizontal resolution regional climate model simulations are used to downscale a total of three different GCMs under the RCP8.5 emissions scenario. Results indicate some possibility for modest increases in precipitation at the leading edge of the Luquillo Mountains in Puerto Rico, but consistent declines elsewhere. We conclude with a discussion of potential explanations for these patterns and the attendant risks to water security that subtropical small island nations could face as the climate warms.

  7. Towards better understanding of the response of Sphagnum peatland to increased temperature and reduced precipitation in Central Europe

    Science.gov (United States)

    Juszczak, Radoslaw; Basińska, Anna; Chojnicki, Bogdan; Gąbka, Maciej; Hoffmann, Mathias; Józefczyk, Damian; Lamentowicz, Mariusz; Leśny, Jacek; Łuców, Dominika; Moni, Christophe; Reczuga, Monika; Samson, Mateusz; Silvennoinen, Hanna; Stróżecki, Marcin; Urbaniak, Marek; Zielińska, Małgorzata; Olejnik, Janusz

    2017-04-01

    With respect to climate change peatlands are highly vulnerable ecosystems. Especially a potential drying in future might result in a major carbon source and release to the atmosphere. We carried out a field climate manipulation experiment at Rzecin peatland in western Poland to assess how increased temperature and reduced precipitation may impact carbon balance, vegetation, microbes and water chemistry of the Sphagnum peatland. Here, we present results of measurements conducted in two contrasting years (417 mm and 678 mm of precipitation in very dry 2015 and wet 2016, respectively). The experimental design consists of four treatments, each one replicated three times (control, CO; simulated warming, W; prolonged drought, D and warming & drought, W+D). Increased temperatures (T) during the year were achieved by infrared heaters (400W × 4 per site, approx. 60 Wṡm-2 addition of LW radiation). Precipitation was reduced using an automatic curtain, covering the site during nighttime hours of the growth seasons. The manipulation experiment was successful during both years, increasing the air (30 cm height) and soil temperature (5 cm depth, sites W and D) by up to 0.2 oC and 1.0 oC, respectively. Precipitation was reduced to 37 % during both years. At W+D site the peat temperature was nearly two times higher than on W site indicating the impact of drought on T increase. To study the C exchange we developed an automatic mobile platform for measuring CO2/CH4/H2O fluxes (LGR) as well as 13CO2 and 13CH4 fluxes (PICARRO CRDS G2201-i). Measurements were performed, using dynamic ecosystem chambers (for NEE and Reco) and combined with simultaneous measurements of surface spectral properties. Flux calculation and gap filling was done according to Hoffmann et al. 2015. Methane emissions were significantly higher on manipulated plots than on CO (25 gCṡm-2yr-1) during both years, but only in the very dry 2015, CH4 fluxes were the highest on W+D site (33 gC gCṡm-2yr-1). Besides

  8. Increased Rotavirus Prevalence in Diarrheal Outbreak Precipitated by Localized Flooding, Solomon Islands, 2014.

    Science.gov (United States)

    Jones, Forrest K; Ko, Albert I; Becha, Chris; Joshua, Cynthia; Musto, Jennie; Thomas, Sarah; Ronsse, Axelle; Kirkwood, Carl D; Sio, Alison; Aumua, Audrey; Nilles, Eric J

    2016-05-01

    Flooding on 1 of the Solomon Islands precipitated a nationwide epidemic of diarrhea that spread to regions unaffected by flooding and caused >6,000 cases and 27 deaths. Rotavirus was identified in 38% of case-patients tested in the city with the most flooding. Outbreak potential related to weather reinforces the need for global rotavirus vaccination.

  9. High resolution TEM study of Ni4Ti3 precipitates in austenitic Ni51Ti49

    International Nuclear Information System (INIS)

    Tirry, Wim; Schryvers, Dominique

    2003-01-01

    Binary NiTi with a composition of 51 at.% Ni was heat treated to form lens-shaped Ni 4 Ti 3 precipitates that are coherent or semi-coherent with the B2 matrix. High resolution transmission electron microscopy (HRTEM) was used to study the internal structure of the precipitates, precipitate-precipitate and matrix-precipitate interfaces and the deformation of the B2 matrix near a precipitate. Observations were made in the B2 and B2 zones and compared with computer simulated high resolution images. The B2 observations made it possible to study the [0 0 1] H zone orientation of Ni 4 Ti 3 (direction defined according to the hexagonal unit cell of Ni 4 Ti 3 ) which corresponds to the normal of the central plane of the discs. In these images the superperiodicity of the 4:3 ordering is clearly visible confirming the known atomic structure. Close to the precipitate the B2 matrix is deformed, as determined by measuring the interplanar spacing from the HRTEM images. The observed deformations are compared with theoretical models for the stress field

  10. High resolution reconstruction of monthly autumn and winter precipitation of Iberian Peninsula for last 150 years.

    Science.gov (United States)

    Cortesi, N.; Trigo, R.; González-Hidalgo, J. C.; Ramos, A.

    2012-04-01

    Precipitation over Iberian Peninsula (IP) presents large values of interannual variability and large spatial contrasts between wet mountainous regions in the north and dry regions in the southern plains. Unlike other European regions, IP was poorly monitored for precipitation during 19th century. Here we present a new approach to fill this gap. A set of 26 atmospheric circulation weather types (Trigo R.M. and DaCamara C.C., 2000) derived from a recent SLP dataset, the EMULATE (European and North Atlantic daily to multidecadal climate variability) Project, was used to reconstruct Iberian monthly precipitation from October to March during 1851-1947. Principal Component Regression Analysis was chosen to develop monthly precipitation reconstruction back to 1851 and calibrated over 1948-2003 period for 3030 monthly precipitation series of high-density homogenized MOPREDAS (Monthly Precipitation Database for Spain and Portugal) database. Validation was conducted over 1920-1947 at 15 key site locations. Results show high model performance for selected months, with a mean coefficient of variation (CV) around 0.6 during validation period. Lower CV values were achieved in western area of IP. Trigo, R. M., and DaCamara, C.C., 2000: "Circulation weather types and their impact on the precipitation regime in Portugal". Int. J. Climatol., 20, 1559-1581.

  11. The full annual carbon balance of Eurasian boreal forests is highly sensitive to precipitation

    Science.gov (United States)

    Öquist, Mats; Bishop, Kevin; Grelle, Achim; Klemedtsson, Leif; Köhler, Stephan; Laudon, Hjalmar; Lindroth, Anders; Ottosson Löfvenius, Mikaell; Wallin, Marcus; Nilsson, Mats

    2013-04-01

    Boreal forest biomes are identified as one of the major sinks for anthropogenic atmospheric CO2 and are also predicted to be particularly sensitive to climate change. Recent advances in understanding the carbon balance of these biomes stems mainly from eddy-covariance measurements of the net ecosystem exchange (NEE). However, NEE includes only the vertical CO2 exchange driven by photosynthesis and ecosystem respiration. A full net ecosystem carbon balance (NECB) also requires inclusion of lateral carbon export (LCE) through catchment discharge. Currently LCE is often regarded as negligible for the NECB of boreal forest ecosystems of the northern hemisphere, commonly corresponding to ~5% of annual NEE. Here we use long term (13 year) data showing that annual LCE and NEE are strongly correlated (p=0.003); years with low C sequestration by the forest coincide with years when lateral C loss is high. The fraction of NEE lost annually through LCE varied markedly from solar radiation caused by clouds. The dual effect of precipitation implies that both the observed and the predicted increases in annual precipitation at high latitudes may reduce NECB in boreal forest ecosystems. Based on regional scaling of hydrological discharge and observed spatio-temporal variations in forest NEE we conclude that our finding is relevant for large areas of the boreal Eurasian landscape.

  12. Infectious precipitants of acute hyperammonemia are associated with indicators of increased morbidity in patients with urea cycle disorders.

    Science.gov (United States)

    McGuire, Peter J; Lee, Hye-Seung; Summar, Marshall L

    2013-12-01

    To prospectively characterize acute hyperammonemic episodes in patients with urea cycle disorders (UCDs) in terms of precipitating factors, treatments, and use of medical resources. This was a prospective, longitudinal observational study of hyperammonemic episodes in patients with UCD enrolled in the National Institutes of Health-sponsored Urea Cycle Disorders Consortium Longitudinal Study. An acute hyperammonemic event was defined as plasma ammonia level >100 μmol/L. Physician-reported data regarding the precipitating event and laboratory and clinical variables were recorded in a central database. In our study population, 128 patients with UCD experienced a total of 413 hyperammonemia events. Most patients experienced between 1 and 3 (65%) or between 4 and 6 (23%) hyperammonemia events since study inception, averaging fewer than 1 event/year. The most common identifiable precipitant was infection (33%), 24% of which were upper/lower respiratory tract infections. Indicators of increased morbidity were seen with infection, including increased hospitalization rates (P = .02), longer hospital stays (+2.0 days; P = .003), and increased use of intravenous ammonia scavengers (+45%-52%; P = .003-.03). Infection is the most common precipitant of acute hyperammonemia in patients with UCD and is associated with indicators of increased morbidity (ie, hospitalization rate, length of stay, and use of intravenous ammonia scavengers). These findings suggest that the catabolic and immune effects of infection may be a target for clinical intervention in inborn errors of metabolism. Published by Mosby, Inc.

  13. High precipitation and seeded species competition reduce seeded shrub establishment during dryland restoration.

    Science.gov (United States)

    Rinella, Matthew J; Hammond, Darcy H; Bryant, Ana-Elisa M; Kozar, Brian J

    2015-06-01

    Drylands comprise 40% of Earth's land mass and are critical to food security, carbon sequestration, and threatened and endangered wildlife. Exotic weed invasions, overgrazing, energy extraction, and other factors have degraded many drylands, and this has placed an increased emphasis on dryland restoration. The increased restoration focus has generated a wealth of experience, innovations and empirical data, yet the goal of restoring diverse, native, dryland plant assemblages composed of grasses, forbs, and shrubs has generally proven beyond reach. Of particular concern are shrubs, which often fail to establish or establish at trivially low densities. We used data from two Great Plains, USA coal mines to explore factors regulating shrub establishment. Our predictor data related to weather and restoration (e.g., seed rates, rock cover) variables, and our response data described shrub abundances on fields of the mines. We found that seeded non-shrubs, especially grasses, formed an important competitive barrier to shrub establishment: With every one standard deviation increase in non-shrub seed rate, the probability shrubs were present decreased ~0.1 and shrub cover decreased ~35%. Since new fields were seeded almost every year for > 20 years, the data also provided a unique opportunity to explore effects of stochastic drivers (i.e., precipitation, year effects). With every one standard deviation increase in precipitation the first growing season following seeding, the probability shrubs were present decreased ~0.07 and shrub cover decreased ~47%. High precipitation appeared to harm shrubs by increasing grass growth/competition. Also, weak evidence suggested shrub establishment was better in rockier fields where grass abundance/competition was lower. Multiple lines of evidence suggest reducing grass seed rates below levels typically used in Great Plains restoration would benefit shrubs without substantially impacting grass stand development over the long term. We used

  14. High resolution reconstruction of monthly precipitation of Iberian Peninsula using circulation weather types

    Science.gov (United States)

    Cortesi, N.; Trigo, R.; Gonzalez-Hidalgo, J. C.; Ramos, A. M.

    2012-06-01

    Precipitation over the Iberian Peninsula (IP) is highly variable and shows large spatial contrasts between wet mountainous regions, to the north, and dry regions in the inland plains and southern areas. In this work, a high-density monthly precipitation dataset for the IP was coupled with a set of 26 atmospheric circulation weather types (Trigo and DaCamara, 2000) to reconstruct Iberian monthly precipitation from October to May with a very high resolution of 3030 precipitation series (overall mean density one station each 200 km2). A stepwise linear regression model with forward selection was used to develop monthly reconstructed precipitation series calibrated and validated over 1948-2003 period. Validation was conducted by means of a leave-one-out cross-validation over the calibration period. The results show a good model performance for selected months, with a mean coefficient of variation (CV) around 0.6 for validation period, being particularly robust over the western and central sectors of IP, while the predicted values in the Mediterranean and northern coastal areas are less acute. We show for three long stations (Lisbon, Madrid and Valencia) the comparison between model and original data as an example to how these models can be used in order to obtain monthly precipitation fields since the 1850s over most of IP for this very high density network.

  15. A continuous and highly effective static mixing process for antisolvent precipitation of nanoparticles of poorly water-soluble drugs.

    Science.gov (United States)

    Dong, Yuancai; Ng, Wai Kiong; Hu, Jun; Shen, Shoucang; Tan, Reginald B H

    2010-02-15

    Rapid and homogeneous mixing of the solvent and antisolvent is critical to achieve submicron drug particles by antisolvent precipitation technique. This work aims to develop a continuous and highly effective static mixing process for antisolvent precipitation of nanoparticles of poorly water-soluble drugs with spironolactone as a model drug. Continuous antisolvent production of drug nanoparticles was carried out with a SMV DN25 static mixer comprising 6-18 mixing elements. The total flow rate ranged from 1.0 to 3.0 L/min while the flow rate ratio of solvent to antisolvent was maintained at 1:9. It is found that only 6 mixing elements were sufficient to precipitate the particles in the submicron range. Increasing the number of elements would further reduce the precipitated particle size. Increasing flow rate from 1.0 to 3.0 L/min did not further reduce the particle size, while higher drug concentrations led to particle size increase. XRD and SEM results demonstrated that the freshly precipitated drug nanoparticles are in the amorphous state, which would, in presence of the mixture of solvent and antisolvent, change to crystalline form in short time. The lyophilized spironolactone nanoparticles with lactose as lyoprotectant possessed good redispersibility and showed 6.6 and 3.3 times faster dissolution rate than that of lyophilized raw drug formulation in 5 and 10 min, respectively. The developed static mixing process exhibits high potential for continuous and large-scale antisolvent precipitation of submicron drug particles. Copyright 2009 Elsevier B.V. All rights reserved.

  16. Response of biological soil crust diazotrophs to season, altered summer precipitation and year-round increased temperature in an arid grassland of the Colorado Plateau, USA

    Directory of Open Access Journals (Sweden)

    Chris M Yeager

    2012-10-01

    Full Text Available Biological soil crusts (biocrusts, which supply significant amounts of fixed nitrogen into terrestrial ecosystems worldwide (~33 Tg y-1, are likely to respond to changes in temperature and precipitation associated with climate change. Using nifH gene-based surveys, we explored variation in the diazotrophic community of biocrusts of the Colorado Plateau, USA in response to season (autumn vs. spring, as well as field manipulations that increased the frequency of small-volume precipitation events and year-round soil temperature. Abundance of nifH genes in biocrusts ranged from 3x106 – 1x108 g-1 soil, and nifH from heterocystous cyanobacteria closely related to Scytonema hyalinum, Spirirestis rafaelensis, and Nostoc commune comprised > 98% of the total. Although there was no apparent seasonal effect on total nifH gene abundance in the biocrusts, T-RFLP analysis revealed a strong seasonal pattern in nifH composition. Spirirestis nifH abundance was estimated to oscillate 1 to >2 orders of magnitude between autumn (low and spring (high. A year-round increase of soil temperature (2 − 3 °C had little effect on the diazotroph community structure over 2 years. Altered summer precipitation had little impact on diazotroph community structure over the first 1.5 years of the study, when natural background patterns across years and seasons superseded any treatment effects. However, after the second summer of treatments, nifH abundance was 2.6 fold lower in biocrusts receiving altered precipitation. Heterocystous cyanobacteria were apparently more resilient to altered precipitation than other cyanobacteria. The results demonstrate that diazotrophic community composition of biocrusts in this semi-arid grassland undergoes strong seasonal shifts and that the abundance of its dominant members decreased in response to more frequent, small-volume precipitation events.

  17. Response of biological soil crust diazotrophs to season, altered summer precipitation, and year-round increased temperature in an arid grassland of the Colorado Plateau, USA

    Science.gov (United States)

    Yeager, Chris M.; Kuske, Cheryl R.; Carney, Travis D.; Johnson, Shannon L.; Ticknor, Lawrence O.; Belnap, Jayne

    2012-01-01

    Biological soil crusts (biocrusts), which supply significant amounts of fixed nitrogen into terrestrial ecosystems worldwide (~33Tg y-1), are likely to respond to changes in temperature and precipitation associated with climate change. Using nifH gene-based surveys, we explored variation in the diazotrophic community of biocrusts of the Colorado Plateau, USA in response to season (autumn vs. spring), as well as field manipulations that increased the frequency of small volume precipitation events and year-round soil temperature. Abundance of nifH genes in biocrusts ranged from 3×106 to 1×8 g-1 soil, and nifH from heterocystous cyanobacteria closely related to Scytonema hyalinum, Spirirestis rafaelensis, and Nostoc commune comprised >98% of the total. Although there was no apparent seasonal effect on total nifH gene abundance in the biocrusts, T-RFLP analysis revealed a strong seasonal pattern in nifH composition. Spirirestis nifH abundance was estimated to oscillate 1 to >2 orders of magnitude between autumn (low) and spring (high). A year-round increase of soil temperature (2–3°C) had little effect on the diazotroph community structure over 2 years. Altered summer precipitation had little impact on diazotroph community structure over the first 1.5years of the study, when natural background patterns across years and seasons superseded any treatment effects. However, after the second summer of treatments, nifH abundance was 2.6-fold lower in biocrusts receiving altered precipitation. Heterocystous cyanobacteria were apparently more resilient to altered precipitation than other cyanobacteria. The results demonstrate that diazotrophic community composition of biocrusts in this semi-arid grassland undergoes strong seasonal shifts and that the abundance of its dominant members decreased in response to more frequent, small volume precipitation events.

  18. Polymer-encapsulated carbon capture liquids that tolerate precipitation of solids for increased capacity

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D; Bourcier, William L; Spadaccini, Christopher M; Stolaroff, Joshuah K

    2015-02-03

    A system for carbon dioxide capture from flue gas and other industrial gas sources utilizes microcapsules with very thin polymer shells. The contents of the microcapsules can be liquids or mixtures of liquids and solids. The microcapsules are exposed to the flue gas and other industrial gas and take up carbon dioxide from the flue gas and other industrial gas and eventual precipitate solids in the capsule.

  19. HEPD on NEXTSat-1: A High Energy Particle Detector for Measurements of Precipitating Radiation Belt Electrons

    Science.gov (United States)

    Sohn, Jongdae; Lee, Jaejin; Min, Kyoungwook; Lee, Junchan; Lee, Seunguk; Lee, Daeyoung; Jo, Gyeongbok; Yi, Yu; Na, Gowoon; Kang, Kyung-In; Shin, Goo-Hwan

    2018-05-01

    Radiation belt particles of the inner magnetosphere precipitate into the atmosphere in the subauroral regions when they are pitch-angle scattered into the loss cone by wave-particle interactions. Such particle precipitations are known to be especially enhanced during space storms, though they can also occur during quiet times. The observed characteristics of precipitating electrons can be distinctively different, in their time series as well as in their spectra, depending on the waves involved. The present paper describes the High Energy Particle Detector (HEPD) on board the Next Generation Small Satellite-1 (NEXTSat-1), which will measure these radiation belt electrons from a low-Earth polar orbit satellite to study the mechanisms related to electron precipitation in the sub-auroral regions. The HEPD is based on silicon barrier detectors and consists of three telescopes that are mounted on the satellite to have angles of 0°. 45°, and 90°, respectively with the local geomagnetic field during observations. With a high time resolution of 32 Hz and a high spectral resolution of 11 channels over the energy range from 350 keV to 2 MeV, together with the pitch angle information provided by the three telescopes, HEPD is capable of identifying physical processes, such as microbursts and dust-side relativistic electron precipitation (DREP) events associated with electron precipitations. NextSat-1 is scheduled for launch in early 2018.

  20. Design of Novel Precipitate-Strengthened Al-Co-Cr-Fe-Nb-Ni High-Entropy Superalloys

    Science.gov (United States)

    Antonov, Stoichko; Detrois, Martin; Tin, Sammy

    2018-01-01

    A series of non-equiatomic Al-Co-Cr-Fe-Nb-Ni high-entropy alloys, with varying levels of Co, Nb and Fe, were investigated in an effort to obtain microstructures similar to conventional Ni-based superalloys. Elevated levels of Co were observed to significantly decrease the solvus temperature of the γ' precipitates. Both Nb and Co in excessive concentrations promoted the formation of Laves and NiAl phases that formed either during solidification and remained undissolved during homogenization or upon high-temperature aging. Lowering the content of Nb, Co, or Fe prevented the formation of the eutectic type Laves. In addition, lowering the Co content resulted in a higher number density and volume fraction of the γ' precipitates, while increasing the Fe content led to the destabilization of the γ' precipitates. Various aging treatments were performed which led to different size distributions of the strengthening phase. Results from the microstructural characterization and hardness property assessments of these high-entropy alloys were compared to a commercial, high-strength Ni-based superalloy RR1000. Potentially, precipitation-strengthened high-entropy alloys could find applications replacing Ni-based superalloys as structural materials in power generation applications.

  1. Strengthening of stainless steel weldment by high temperature precipitation

    OpenAIRE

    Sergio Neves Monteiro; Lucio Fabio Cassiano Nascimento; Édio Pereira Lima, Jr.; Fernanda Santos da Luz; Eduardo Sousa Lima; Fábio de Oliveira Braga

    2017-01-01

    The mechanical behavior and the strengthening mechanism of stainless steel welded joints at 600 °C have been investigated. The welds were composed of AISI 304 stainless steel, as base metal, and niobium containing AISI 347 stainless steel, as weld metal. The investigation was conducted by means of creep tests. The welded specimens were subjected to both high temperature (600 °C) and long periods (up to 2000 h) under constant load, and both mechanical properties and microstructural changes in ...

  2. Influence of rolling direction and carbide precipitation on IGSCC susceptibility in hydrogenated high temperature water

    International Nuclear Information System (INIS)

    Arioka, Koji; Yamada, Takuyo; Terachi, Takumi; Chiba, Goro

    2005-01-01

    IGSCC growth behaviors of austenitic stainless steels in hydrogenated high temperature water were studied using compact type specimens (0.5T for cold worked materials). The effect of cold rolling direction, alloy composition and carbide precipitation on crack growth behaviors was studied in hydrogenated high temperature water. Then, to examine the effect of cold work and carbide precipitation on IGSCC behaviors, the role of grain boundary sliding studied in high temperature air using CT specimens. The similar dependences of carbide precipitation and cold work on IGSCC and creep behaviors suggest that grain boundary sliding might play an important role by itself or in conjunction with other reactions such as crack tip dissolution etc. (author)

  3. Future Projection of Summer Extreme Precipitation from High Resolution Multi-RCMs over East Asia

    Science.gov (United States)

    Kim, Gayoung; Park, Changyong; Cha, Dong-Hyun; Lee, Dong-Kyou; Suh, Myoung-Seok; Ahn, Joong-Bae; Min, Seung-Ki; Hong, Song-You; Kang, Hyun-Suk

    2017-04-01

    Recently, the frequency and intensity of natural hazards have been increasing due to human-induced climate change. Because most damages of natural hazards over East Asia have been related to extreme precipitation events, it is important to estimate future change in extreme precipitation characteristics caused by climate change. We investigate future changes in extremal values of summer precipitation simulated by five regional climate models participating in the CORDEX-East Asia project (i.e., HadGEM3-RA, RegCM4, MM5, WRF, and GRIMs) over East Asia. 100-year return value calculated from the generalized extreme value (GEV) parameters is analysed as an indicator of extreme intensity. In the future climate, the mean values as well as the extreme values of daily precipitation tend to increase over land region. The increase of 100-year return value can be significantly associated with the changes in the location (intensity) and scale (variability) GEV parameters for extreme precipitation. It is expected that the results of this study can be used as fruitful references when making the policy of disaster management. Acknowledgements The research was supported by the Ministry of Public Safety and Security of Korean government and Development program under grant MPSS-NH-2013-63 and the National Research Foundation of Korea Grant funded by the Ministry of Science, ICT and Future Planning of Korea (NRF-2016M3C4A7952637) for its support and assistant in completion of the study.

  4. Effects of belowground litter addition, increased precipitation and clipping on soil carbon and nitrogen mineralization in a temperate steppe

    OpenAIRE

    Ma, L.; Guo, C.; Xin, X.; Yuan, S.; Wang, R.

    2013-01-01

    Soil carbon (C) and nitrogen (N) cycling are sensitive to changes in environmental factors and play critical roles in the responses of terrestrial ecosystems to natural and anthropogenic perturbations. This study was conducted to quantify the effects of belowground particulate litter (BPL) addition, increased precipitation and their interactions on soil C and N mineralization in two adjacent sites where belowground photosynthate allocation was manipulated through vegetation ...

  5. Understanding Single-Thread Meandering Rivers with High Sinuosity on Mars through Chemical Precipitation Experiments

    Science.gov (United States)

    Lim, Y.; Kim, W.

    2015-12-01

    Meandering rivers are extremely ubiquitous on Earth, yet it is only recently that single-thread experimental channels with low sinuosity have been created. In these recent experiments, as well as in natural rivers, vegetation plays a crucial role in maintaining a meandering pattern by adding cohesion to the bank and inhibiting erosion. The ancient, highly sinuous channels found on Mars are enigmatic because presumably vegetation did not exist on ancient Mars. Under the hypothesis that Martian meandering rivers formed by chemical precipitation on levees and flood plain deposits, we conducted carbonate flume experiments to investigate the formation and evolution of a single-thread meander pattern without vegetation. The flow recirculating in the flume is designed to accelerate chemical reactions - dissolution of limestone using CO2 gas to produce artificial spring water and precipitation of carbonates to increase cohesion- with precise control of water discharge, sediment discharge, and temperature. Preliminary experiments successfully created a single-thread meandering pattern through chemical processes. Carbonate deposits focused along the channel sides improved the bank stability and made them resistant to erosion, which led to a stream confined in a narrow path. The experimental channels showed lateral migration of the bend through cut bank and point bar deposits; intermittent floods created overbank flow and encouraged cut bank erosion, which enhanced lateral migration of the channel, while increase in sediment supply improved lateral point bar deposition, which balanced erosion and deposition rates. This mechanism may be applied to terrestrial single-thread and/or meandering rivers with little to no vegetation or before its introduction to Earth and also provide the link between meandering river records on Mars to changes in Martian surface conditions.

  6. G-phase precipitation in austenitic stainless steel deformed by high pressure torsion

    Energy Technology Data Exchange (ETDEWEB)

    Shuro, I., E-mail: innoshuro@martens.me.tut.ac.jp [Functional Materials Engineering, Toyohashi University of Technology, 1-1, Toyohashi, Aichi 441-8580 (Japan); Kuo, H.H. [Functional Materials Engineering, Toyohashi University of Technology, 1-1, Toyohashi, Aichi 441-8580 (Japan); Sasaki, T.; Hono, K. [National Institute for Materials Sciences, Sengen 1-2-1, Tsukuba 305-0047 (Japan); Todaka, Y.; Umemoto, M. [Functional Materials Engineering, Toyohashi University of Technology, 1-1, Toyohashi, Aichi 441-8580 (Japan)

    2012-08-30

    Highlights: Black-Right-Pointing-Pointer Using TEM and APT analyses, G-phase precipitation was observed in HPTed SUS304 with no trace of spinodal decomposition. Black-Right-Pointing-Pointer G-phase precipitation occurred much shorter time than previous studies probably due to the elimination of prior SD and enhanced diffusion by severe plastic deformation. Black-Right-Pointing-Pointer G-phase composition is a function of aging time. Black-Right-Pointing-Pointer Tensile tests showed that in SUS304 embrittlement occurs solely due to G-phase precipitation. - Abstract: G phase an intermetallic silicide has been observed in martensite of precipitation hardened stainless steels and in the ferrite of dual (austenite and ferrite) phase stainless steels. In both cases, before G-phase precipitates, the matrix composition changes due to spinodal decomposition and solute partitioning between ferrite and austenite. Thus in the present study, single bcc phase and high Ni content stainless steel, was selected to study G-phase precipitation expecting elimination of the interference from spinodal decomposition and solute partitioning. Fe-18Cr-8Ni (SUS304) austenitic stainless steel samples were deformed at room temperature by high pressure torsion to obtain 100% volume fraction of deformation induced martensite ({alpha} Prime ). HPT deformation was chosen due to its ability to induce high strength by grain refinement and also attain 100% {alpha} Prime at room temperature. After annealing at 400 Degree-Sign C for 500 h, G-phase precipitation was observed in the fully martensitic matrix without spinodal decomposition. Crystallographic analysis of annealed samples using high resolution transmission electron microscopy (HRTEM) and energy dispersive spectroscopy (EDS) detected a Mn-Ni-Si rich G-phase with fcc crystal structure with lattice parameter of 1.16 nm. The value of lattice parameter corresponds well with previously reported values. Chemical analysis by atom probe tomography

  7. G-phase precipitation in austenitic stainless steel deformed by high pressure torsion

    International Nuclear Information System (INIS)

    Shuro, I.; Kuo, H.H.; Sasaki, T.; Hono, K.; Todaka, Y.; Umemoto, M.

    2012-01-01

    Highlights: ► Using TEM and APT analyses, G-phase precipitation was observed in HPTed SUS304 with no trace of spinodal decomposition. ► G-phase precipitation occurred much shorter time than previous studies probably due to the elimination of prior SD and enhanced diffusion by severe plastic deformation. ► G-phase composition is a function of aging time. ► Tensile tests showed that in SUS304 embrittlement occurs solely due to G-phase precipitation. - Abstract: G phase an intermetallic silicide has been observed in martensite of precipitation hardened stainless steels and in the ferrite of dual (austenite and ferrite) phase stainless steels. In both cases, before G-phase precipitates, the matrix composition changes due to spinodal decomposition and solute partitioning between ferrite and austenite. Thus in the present study, single bcc phase and high Ni content stainless steel, was selected to study G-phase precipitation expecting elimination of the interference from spinodal decomposition and solute partitioning. Fe–18Cr–8Ni (SUS304) austenitic stainless steel samples were deformed at room temperature by high pressure torsion to obtain 100% volume fraction of deformation induced martensite (α′). HPT deformation was chosen due to its ability to induce high strength by grain refinement and also attain 100% α′ at room temperature. After annealing at 400 °C for 500 h, G-phase precipitation was observed in the fully martensitic matrix without spinodal decomposition. Crystallographic analysis of annealed samples using high resolution transmission electron microscopy (HRTEM) and energy dispersive spectroscopy (EDS) detected a Mn–Ni–Si rich G-phase with fcc crystal structure with lattice parameter of 1.16 nm. The value of lattice parameter corresponds well with previously reported values. Chemical analysis by atom probe tomography (APT) showed G-phase of composition Mn 21 Ni 50 Si 24 Fe 4 Cr. Tensile tests showed that G-phase precipitation leads to

  8. Inter-Comparison of High-Resolution Satellite Precipitation Products over Central Asia

    Directory of Open Access Journals (Sweden)

    Hao Guo

    2015-06-01

    Full Text Available This paper examines the spatial error structures of eight precipitation estimates derived from four different satellite retrieval algorithms including TRMM Multi-satellite Precipitation Analysis (TMPA, Climate Prediction Center morphing technique (CMORPH, Global Satellite Mapping of Precipitation (GSMaP and Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN. All the original satellite and bias-corrected products of each algorithm (3B42RTV7 and 3B42V7, CMORPH_RAW and CMORPH_CRT, GSMaP_MVK and GSMaP_Gauge, PERSIANN_RAW and PERSIANN_CDR are evaluated against ground-based Asian Precipitation-Highly Resolved Observational Data Integration Towards Evaluation of Water Resources (APHRODITE over Central Asia for the period of 2004 to 2006. The analyses show that all products except PERSIANN exhibit overestimation over Aral Sea and its surrounding areas. The bias-correction improves the quality of the original satellite TMPA products and GSMaP significantly but slightly in CMORPH and PERSIANN over Central Asia. 3B42RTV7 overestimates precipitation significantly with large Relative Bias (RB (128.17% while GSMaP_Gauge shows consistent high correlation coefficient (CC (>0.8 but RB fluctuates between −57.95% and 112.63%. The PERSIANN_CDR outperforms other products in winter with the highest CC (0.67. Both the satellite-only and gauge adjusted products have particularly poor performance in detecting rainfall events in terms of lower POD (less than 65%, CSI (less than 45% and relatively high FAR (more than 35%.

  9. Acute Precipitants of Physical Elder Abuse: Qualitative Analysis of Legal Records From Highly Adjudicated Cases.

    Science.gov (United States)

    Rosen, Tony; Bloemen, Elizabeth M; LoFaso, Veronica M; Clark, Sunday; Flomenbaum, Neal E; Breckman, Risa; Markarian, Arlene; Riffin, Catherine; Lachs, Mark S; Pillemer, Karl

    2016-08-01

    Elder abuse is a common phenomenon with potentially devastating consequences for older adults. Although researchers have begun to identify predisposing risk factors for elder abuse victims and abusers, little is known about the acute precipitants that lead to escalation to physical violence. We analyzed legal records from highly adjudicated cases to describe these acute precipitants for physical elder abuse. In collaboration with a large, urban district attorney's office, we qualitatively evaluated legal records from 87 successfully prosecuted physical elder abuse cases from 2003 to 2015. We transcribed and analyzed narratives of the events surrounding physical abuse within victim statements, police reports, and prosecutor records. We identified major themes using content analysis. We identified 10 categories of acute precipitants that commonly triggered physical elder abuse, including victim attempting to prevent the abuser from entering or demanding that he or she leave, victim threatening or attempting to leave/escape, threat or perception that the victim would involve the authorities, conflict about a romantic relationship, presence during/intervention in ongoing family violence, issues in multi-generational child rearing, conflict about the abuser's substance abuse, confrontation about financial exploitation, dispute over theft/destruction of property, and disputes over minor household issues. Common acute precipitants of physical elder abuse may be identified. Improved understanding of these acute precipitants for escalation to physical violence and their contribution to elder abuse may assist in the development of prevention and management strategies.

  10. Descriptive and predictive evaluation of high resolution Markov chain precipitation models

    DEFF Research Database (Denmark)

    Sørup, Hjalte Jomo Danielsen; Madsen, Henrik; Arnbjerg-Nielsen, Karsten

    2012-01-01

    A time series of tipping bucket recordings of very high temporal and volumetric resolution precipitation is modelled using Markov chain models. Both first and second‐order Markov models as well as seasonal and diurnal models are investigated and evaluated using likelihood based techniques. The fi...

  11. Strengthening effect of nano-scaled precipitates in Ta alloying layer induced by high current pulsed electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Guangze; Luo, Dian; Fan, Guohua [School of Material Science & Engineering, Harbin Institute of Technology, Harbin 150001 (China); Ma, Xinxin, E-mail: maxin@hit.edu.cn [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Wang, Liqin [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2017-05-01

    Highlights: • Ta alloying layer are fabricated by magnetron sputtering and high current pulsed electron beam. • Nano-scaled TaC precipitates forms within the δ-Fe grain after tempering treatment. • The mean diameter of TaC particles is about 5–8 nm. • The hardness of alloying layer increased by over 50% after formation of nano-scaled TaC particle. - Abstract: In this study, the combination of magnetron sputtering and high current pulsed electron beam are used for surface alloying treatment of Ta film on high speed steel. And the Ta alloying layer is about 6 μm. After tempering treatment, TaC phase forms in Ta alloying layer when the treated temperature is over 823 K. Through the TEM and HRTEM observation, a large amount of nano-scaled precipitates (mean diameter 5–8 nm) form within the δ-Fe grain in Ta alloying layer after tempering treatment and these nano-scaled precipitates are confirmed as TaC particles, which contribute to the strengthening effect of the surface alloying layer. The hardness of tempered alloying layer can reach to 18.1 GPa when the treated temperature is 823 K which increase by 50% comparing with the untreated steel sample before surface alloying treatment.

  12. High-resolution precipitation mapping in a mountainous watershed: ground truth for evaluating uncertainty in a national precipitation dataset

    Science.gov (United States)

    Christopher Daly; Melissa E. Slater; Joshua A. Roberti; Stephanie H. Laseter; Lloyd W. Swift

    2017-01-01

    A 69-station, densely spaced rain gauge network was maintained over the period 1951–1958 in the Coweeta Hydrologic Laboratory, located in the southern Appalachians in western North Carolina, USA. This unique dataset was used to develop the first digital seasonal and annual precipitation maps for the Coweeta basin, using elevation regression functions and...

  13. Regional Scale High Resolution δ18O Prediction in Precipitation Using MODIS EVI

    Science.gov (United States)

    Huang, Cho-Ying; Wang, Chung-Ho; Lin, Shou-De; Lo, Yi-Chen; Huang, Bo-Wen; Hatch, Kent A.; Shiu, Hau-Jie; You, Cheng-Feng; Chang, Yuan-Mou; Shen, Sheng-Feng

    2012-01-01

    The natural variation in stable water isotope ratio data, also known as water isoscape, is a spatiotemporal fingerprint and a powerful natural tracer that has been widely applied in disciplines as diverse as hydrology, paleoclimatology, ecology and forensic investigation. Although much effort has been devoted to developing a predictive water isoscape model, it remains a central challenge for scientists to generate high accuracy, fine scale spatiotemporal water isoscape prediction. Here we develop a novel approach of using the MODIS-EVI (the Moderate Resolution Imagining Spectroradiometer-Enhanced Vegetation Index), to predict δ18O in precipitation at the regional scale. Using a structural equation model, we show that the EVI and precipitated δ18O are highly correlated and thus the EVI is a good predictor of precipitated δ18O. We then test the predictability of our EVI-δ18O model and demonstrate that our approach can provide high accuracy with fine spatial (250×250 m) and temporal (16 days) scale δ18O predictions (annual and monthly predictabilities [r] are 0.96 and 0.80, respectively). We conclude the merging of the EVI and δ18O in precipitation can greatly extend the spatial and temporal data availability and thus enhance the applicability for both the EVI and water isoscape. PMID:23029053

  14. Precipitation behavior during thin slab thermomechanical processing and isothermal aging of copper-bearing niobium-microalloyed high strength structural steels: The effect on mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Misra, R.D.K., E-mail: dmisra@louisiana.edu [Center for Structural and Functional Materials, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA 70503 (United States); Jia, Z. [Center for Structural and Functional Materials, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA 70503 (United States); O' Malley, R. [Nucor Steel Decatur, LLC Sheet Mill, 4301, Iverson Blvd., Trinity, AL 35673 (United States); Jansto, S.J. [CBMM-Reference Metals Company, 1000 Old Pond Road, Bridgeville, PA 15017 (United States)

    2011-11-15

    Highlights: {yields} Copper does not significantly influence toughness. {yields} Copper precipitation during aging occurs at dislocations. {yields} Precipitation of copper and carbides is mutually exclusive. - Abstract: We describe here the precipitation behavior of copper and fine-scale carbides during thermo-mechanical processing and isothermal aging of copper-bearing niobium-microalloyed high strength steels. During thermo-mechanical processing, precipitation of {epsilon}-copper occurs in polygonal ferrite and at the austenite-ferrite interface. In contrast, during isothermal aging, nucleation of {epsilon}-copper precipitation occurs at dislocations. In the three different chemistries investigated, the increase in strength associated with copper during aging results only in a small decrease in impact toughness, implying that copper precipitates do not seriously impair toughness, and can be considered as a viable strengthening element in microalloyed steels. Precipitation of fine-scale niobium carbides occurs extensively at dislocations and within ferrite matrix together with vanadium carbides. In the presence of titanium, titanium carbides act as a nucleus for niobium carbide formation. Irrespective of the nature of carbides, copper precipitates and carbides are mutually exclusive.

  15. Precipitation behavior during thin slab thermomechanical processing and isothermal aging of copper-bearing niobium-microalloyed high strength structural steels: The effect on mechanical properties

    International Nuclear Information System (INIS)

    Misra, R.D.K.; Jia, Z.; O'Malley, R.; Jansto, S.J.

    2011-01-01

    Highlights: → Copper does not significantly influence toughness. → Copper precipitation during aging occurs at dislocations. → Precipitation of copper and carbides is mutually exclusive. - Abstract: We describe here the precipitation behavior of copper and fine-scale carbides during thermo-mechanical processing and isothermal aging of copper-bearing niobium-microalloyed high strength steels. During thermo-mechanical processing, precipitation of ε-copper occurs in polygonal ferrite and at the austenite-ferrite interface. In contrast, during isothermal aging, nucleation of ε-copper precipitation occurs at dislocations. In the three different chemistries investigated, the increase in strength associated with copper during aging results only in a small decrease in impact toughness, implying that copper precipitates do not seriously impair toughness, and can be considered as a viable strengthening element in microalloyed steels. Precipitation of fine-scale niobium carbides occurs extensively at dislocations and within ferrite matrix together with vanadium carbides. In the presence of titanium, titanium carbides act as a nucleus for niobium carbide formation. Irrespective of the nature of carbides, copper precipitates and carbides are mutually exclusive.

  16. Enhanced electrochemical sensitivity of enzyme precipitate coating (EPC)-based glucose oxidase biosensors with increased free CNT loadings.

    Science.gov (United States)

    Kim, Jae Hyun; Jun, Sun-Ae; Kwon, Yongchai; Ha, Su; Sang, Byong-In; Kim, Jungbae

    2015-02-01

    Enzymatic electrodes were fabricated by using three different immobilizations of glucose oxidase (GOx): covalent enzyme attachment (CA), enzyme coating (EC), and enzyme precipitate coating (EPC), here referred to as CA-E, EC-E, and EPC-E, respectively. When additional carbon nanotubes (CNTs) were introduced from 0 to 75wt% for the EPC-E design, its initial biosensor sensitivity was improved from 2.40×10(-3) to 16.26×10(-3) A∙M(-1)∙cm(-2), while its electron charge transfer rate constant was increased from 0.33 to 1.47s(-1). When a fixed ratio of CNTs was added for three different electrode systems, EPC-E showed the best glucose sensitivity and long-term thermal stability. For example, when 75wt% of additional CNTs was added, the initial sensitivity of EPC-E was 16.26×10(-3) A∙M(-1)∙cm(-2), while those of EC-E and CA-E were only 6.42×10(-3) and 1.18×10(-3) A∙M(-1)∙cm(-2), respectively. Furthermore, EPC-E retained 63% of its initial sensitivity after thermal treatment at 40°C over 41days, while EC-E and CA-E showed only 12% and 1% of initial sensitivities, respectively. Consequently, the EPC approach with additional CNTs achieved both high sensitivity and long-term stability, which are required for continuous and accurate glucose monitoring. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Analysis of High Temperature Deformed Structure and Dynamic Precipitation in W9Mo3Cr4V Steel

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    With TEM、SEM, various high-temperature deformed structures inW9Mo3Cr4V steel were investigated. The sub-structures,recrystallized nuclei, as well as the dynamic precipitation were also studied and analyzed. The relationship between recrystallized structures and dynamic precipitation was discussed. The results showed that the deformed structures in W9Mo3Cr4V steel are more complicated than those in low alloy steels. Because W9Mo3Cr4V steel is a high-speed steel, there are a large number of residual carbides on the matrix. Also, much dynamic precipitating carbides will precipitate during deformation at high temperature.

  18. Influence of precipitations, buildings and over increase of radioactive emission in the population dose calculation under accident conditions

    International Nuclear Information System (INIS)

    Conte, M.C.

    1987-01-01

    The influence of precipitations is analyzed, as well as of buildings and emission over increase on the dosis produced on the population as a consequence of some postulated accidents in Atucha II nuclear power plant. The following conclusions were achieved: the calculations performed without considering the above mentioned effects are conservative, excluding the case in which the precipitation is very close to the emission source. In this case, the maximal difference observed was 20% for class C and 5% for class D, at 1 km from source, with a decreasing difference according to the distance. The doses calculated without building effect were approximately 25% greater than those calculated considering this effect for class E and 40% for class F, at 1 km from the source. The difference decreases with distance and increases with the stability of atmospheric conditions. This behaviour is also observed with the over increase effect. In this case, the maximal observed differences were of one order of magnitude for class E and three orders for class F, at 1 km from the source. (Author)

  19. High salinity facilitates dolomite precipitation mediated by Haloferax volcanii DS52

    Science.gov (United States)

    Qiu, Xuan; Wang, Hongmei; Yao, Yanchen; Duan, Yong

    2017-08-01

    Although most modern dolomites occur in hypersaline environments, the effects of elevated salinity on the microbial mediation of dolomite precipitation have not been fully evaluated. Here we report results of dolomite precipitation in association with a batch culture of Haloferax volcanii DS52, a halophilic archaeon, under various salinities (from 120‰ to 360‰) and the impact of salinity on microbe-mediated dolomite formation. The mineral phases, morphology and atomic arrangement of the precipitates were analyzed by XRD, SEM and TEM, respectively. The amount of amino acids on the archaeal cell surface was quantified by HPLC/MS. The XRD analysis indicated that disordered dolomite formed successfully with the facilitation of cells harvested from cultures with relatively high salinities (200‰ and 280‰) but was not observed in association with cells harvested from cultures with lower salinity (120‰) or the lysates of cells harvested from extremely high salinity (360‰). The TEM analysis demonstrated that the crystals from cultures with a salinity of 200‰ closely matched that of dolomite. Importantly, we found that more carboxyl groups were presented on the cell surface under high salinity conditions to resist the high osmotic pressure, which may result in the subsequent promotion of dolomite formation. Our finding suggests a link between variations in the hydro-chemical conditions and the formation of dolomite via microbial metabolic activity and enhances our understanding about the mechanism of microbially mediated dolomite formation under high salinity conditions.

  20. Deformation-Induced Dissolution and Precipitation of Nitrides in Austenite and Ferrite of a High-Nitrogen Stainless Steel

    Science.gov (United States)

    Shabashov, V. A.; Makarov, A. V.; Kozlov, K. A.; Sagaradze, V. V.; Zamatovskii, A. E.; Volkova, E. G.; Luchko, S. N.

    2018-02-01

    Methods of Mössbauer spectroscopy and electron microscopy have been used to study the effect of the severe plastic deformation by high pressure torsion in Bridgman anvils on the dissolution and precipitation of chromium nitrides in the austenitic and ferritic structure of an Fe71.2Cr22.7Mn1.3N4.8 high-nitrogen steel. It has been found that an alternative process of dynamic aging with the formation of secondary nitrides affects the kinetics of the dissolution of chromium nitrides. The dynamic aging of ferrite is activated with an increase in the deformation temperature from 80 to 573 K.

  1. Local likelihood estimation of complex tail dependence structures in high dimensions, applied to US precipitation extremes

    KAUST Repository

    Camilo, Daniela Castro

    2017-10-02

    In order to model the complex non-stationary dependence structure of precipitation extremes over the entire contiguous U.S., we propose a flexible local approach based on factor copula models. Our sub-asymptotic spatial modeling framework yields non-trivial tail dependence structures, with a weakening dependence strength as events become more extreme, a feature commonly observed with precipitation data but not accounted for in classical asymptotic extreme-value models. To estimate the local extremal behavior, we fit the proposed model in small regional neighborhoods to high threshold exceedances, under the assumption of local stationarity. This allows us to gain in flexibility, while making inference for such a large and complex dataset feasible. Adopting a local censored likelihood approach, inference is made on a fine spatial grid, and local estimation is performed taking advantage of distributed computing resources and of the embarrassingly parallel nature of this estimation procedure. The local model is efficiently fitted at all grid points, and uncertainty is measured using a block bootstrap procedure. An extensive simulation study shows that our approach is able to adequately capture complex, non-stationary dependencies, while our study of U.S. winter precipitation data reveals interesting differences in local tail structures over space, which has important implications on regional risk assessment of extreme precipitation events. A comparison between past and current data suggests that extremes in certain areas might be slightly wider in extent nowadays than during the first half of the twentieth century.

  2. Advances in Understanding the Role of Frozen Precipitation in High Latitude Hydrology

    Science.gov (United States)

    L'Ecuyer, T. S.; Wood, N.; Smalley, M.; McIlhattan, E.; Kulie, M.

    2017-12-01

    Satellite-based millimeter wavelength radar observations provide a unique perspective on the global character of frozen precipitation that has been difficult to detect using conventional spaceborne precipitation sensors. This presentation will describe the methodology underpinning the ten-year CloudSat global snowfall product and discuss the results of a number of complementary approaches that have been adopted to quantify its uncertainties. These datasets are shedding new light on the distribution, character, and impacts of frozen precipitation on high latitude hydrology. Inferred regional snowfall accumulations, for example, provide valuable constraints on projected changes in precipitation and mass balance on the Antarctic ice sheet in climate models. When placed in the broader context of complementary observations from other A-Train sensors, instantaneous snowfall estimates also hint at the large-scale processes that influence snow formation including air-sea interactions associated with cold-air outbreaks, lake-effect snows, and orographic enhancement. Simultaneous CloudSat and CALIPSO observations further emphasize the important role snowfall plays in the lifetime of super-cooled liquid containing clouds in the Arctic and highlight a model deficiency with important implications for surface energy and mass balance on the Greenland ice sheet.

  3. Local likelihood estimation of complex tail dependence structures in high dimensions, applied to US precipitation extremes

    KAUST Repository

    Camilo, Daniela Castro; Huser, Raphaë l

    2017-01-01

    In order to model the complex non-stationary dependence structure of precipitation extremes over the entire contiguous U.S., we propose a flexible local approach based on factor copula models. Our sub-asymptotic spatial modeling framework yields non-trivial tail dependence structures, with a weakening dependence strength as events become more extreme, a feature commonly observed with precipitation data but not accounted for in classical asymptotic extreme-value models. To estimate the local extremal behavior, we fit the proposed model in small regional neighborhoods to high threshold exceedances, under the assumption of local stationarity. This allows us to gain in flexibility, while making inference for such a large and complex dataset feasible. Adopting a local censored likelihood approach, inference is made on a fine spatial grid, and local estimation is performed taking advantage of distributed computing resources and of the embarrassingly parallel nature of this estimation procedure. The local model is efficiently fitted at all grid points, and uncertainty is measured using a block bootstrap procedure. An extensive simulation study shows that our approach is able to adequately capture complex, non-stationary dependencies, while our study of U.S. winter precipitation data reveals interesting differences in local tail structures over space, which has important implications on regional risk assessment of extreme precipitation events. A comparison between past and current data suggests that extremes in certain areas might be slightly wider in extent nowadays than during the first half of the twentieth century.

  4. A High-Throughput, Precipitating Colorimetric Sandwich ELISA Microarray for Shiga Toxins

    Directory of Open Access Journals (Sweden)

    Andrew Gehring

    2014-06-01

    Full Text Available Shiga toxins 1 and 2 (Stx1 and Stx2 from Shiga toxin-producing E. coli (STEC bacteria were simultaneously detected with a newly developed, high-throughput antibody microarray platform. The proteinaceous toxins were immobilized and sandwiched between biorecognition elements (monoclonal antibodies and pooled horseradish peroxidase (HRP-conjugated monoclonal antibodies. Following the reaction of HRP with the precipitating chromogenic substrate (metal enhanced 3,3-diaminobenzidine tetrahydrochloride or DAB, the formation of a colored product was quantitatively measured with an inexpensive flatbed page scanner. The colorimetric ELISA microarray was demonstrated to detect Stx1 and Stx2 at levels as low as ~4.5 ng/mL within ~2 h of total assay time with a narrow linear dynamic range of ~1–2 orders of magnitude and saturation levels well above background. Stx1 and/or Stx2 produced by various strains of STEC were also detected following the treatment of cultured cells with mitomycin C (a toxin-inducing antibiotic and/or B-PER (a cell-disrupting, protein extraction reagent. Semi-quantitative detection of Shiga toxins was demonstrated to be sporadic among various STEC strains following incubation with mitomycin C; however, further reaction with B-PER generally resulted in the detection of or increased detection of Stx1, relative to Stx2, produced by STECs inoculated into either axenic broth culture or culture broth containing ground beef.

  5. A climatological analysis of high-precipitation events in Dronning Maud Land, Antarctica, and associated large-scale atmospheric conditions

    NARCIS (Netherlands)

    Welker, Christoph; Martius, Olivia; Froidevaux, Paul; Reijmer, Carleen H.; Fischer, Hubertus

    2014-01-01

    The link between high precipitation in Dronning Maud Land (DML), Antarctica, and the large-scale atmospheric circulation is investigated using ERA-Interim data for 1979-2009. High-precipitation events are analyzed at Halvfarryggen situated in the coastal region of DML and at Kohnen Station located

  6. Chemistry and isotopic composition of precipitation and surface waters in Khumbu valley (Nepal Himalaya): N dynamics of high elevation basins.

    Science.gov (United States)

    Balestrini, Raffaella; Polesello, Stefano; Sacchi, Elisa

    2014-07-01

    We monitored the chemical and isotopic compositions of wet depositions, at the Pyramid International Laboratory (5050 ma.s.l.), and surrounding surface waters, in the Khumbu basin, to understand precipitation chemistry and to obtain insights regarding ecosystem responses to atmospheric inputs. The major cations in the precipitation were NH4(+) and Ca(2+), whereas the main anion was HCO3(-), which constituted approximately 69% of the anions, followed by NO3(-), SO4(2-) and Cl(-). Data analysis suggested that Na(+), Cl(-) and K(+) were derived from the long-range transport of marine aerosols. Ca(2+), Mg(2+) and HCO3(-) were related to rock and soil dust contributions and the NO3(-) and SO4(2-) concentrations were derived from anthropogenic sources. Furthermore, NH4(+) was derived from gaseous NH3 scavenging. The isotopic composition of weekly precipitation ranged from -1.9 to -23.2‰ in δ(18)O, and from -0.8 to -174‰ in δ(2)H, with depleted values characterizing the central part of the monsoon period. The chemical composition of the stream water was dominated by calcite and/or gypsum dissolution. However, the isotopic composition of the stream water did not fully reflect the composition of the monsoon precipitation, which suggested that other water sources contributed to the stream flow. Precipitation contents for all ions were the lowest ones among those measured in high elevation sites around the world. During the monsoon periods the depositions were not substantially influenced by anthropogenic inputs, while in pre- and post-monsoon seasons the Himalayas could not represent an effective barrier for airborne pollution. In the late monsoon phase, the increase of ionic contents in precipitation could also be due to a change in the moisture source. The calculated atmospheric N load (0.30 kg ha(-1) y(-1)) was considerably lower than the levels that were measured in other high-altitude environments. Nevertheless, the NO3(-) concentrations in the surface waters

  7. Chemistry and isotopic composition of precipitation and surface waters in Khumbu valley (Nepal Himalaya): N dynamics of high elevation basins

    International Nuclear Information System (INIS)

    Balestrini, Raffaella; Polesello, Stefano; Sacchi, Elisa

    2014-01-01

    We monitored the chemical and isotopic compositions of wet depositions, at the Pyramid International Laboratory (5050 m a.s.l.), and surrounding surface waters, in the Khumbu basin, to understand precipitation chemistry and to obtain insights regarding ecosystem responses to atmospheric inputs. The major cations in the precipitation were NH 4 + and Ca 2+ , whereas the main anion was HCO 3 − , which constituted approximately 69% of the anions, followed by NO 3 − , SO 4 2− and Cl − . Data analysis suggested that Na + , Cl − and K + were derived from the long-range transport of marine aerosols. Ca 2+ , Mg 2+ and HCO 3 − were related to rock and soil dust contributions and the NO 3 − and SO 4 2− concentrations were derived from anthropogenic sources. Furthermore, NH 4 + was derived from gaseous NH 3 scavenging. The isotopic composition of weekly precipitation ranged from − 1.9 to − 23.2‰ in δ 18 O, and from − 0.8 to − 174‰ in δ 2 H, with depleted values characterizing the central part of the monsoon period. The chemical composition of the stream water was dominated by calcite and/or gypsum dissolution. However, the isotopic composition of the stream water did not fully reflect the composition of the monsoon precipitation, which suggested that other water sources contributed to the stream flow. Precipitation contents for all ions were the lowest ones among those measured in high elevation sites around the world. During the monsoon periods the depositions were not substantially influenced by anthropogenic inputs, while in pre- and post-monsoon seasons the Himalayas could not represent an effective barrier for airborne pollution. In the late monsoon phase, the increase of ionic contents in precipitation could also be due to a change in the moisture source. The calculated atmospheric N load (0.30 kg ha −1 y −1 ) was considerably lower than the levels that were measured in other high-altitude environments. Nevertheless, the NO 3

  8. A new approach for assimilation of 2D radar precipitation in a high-resolution NWP model

    DEFF Research Database (Denmark)

    Korsholm, Ulrik Smith; Petersen, Claus; Sass, Bent Hansen

    2015-01-01

    of precipitation, the strength of the nudging is proportional to the offset between observed and modelled precipitation, leading to increased moisture convergence. If the model over-predicts precipitation, the low level moisture source is reduced, and in-cloud moisture is nudged towards environmental values......A new approach for assimilation of 2D precipitation in numerical weather prediction models is presented and tested in a case with convective, heavy precipitation. In the scheme a nudging term is added to the horizontal velocity divergence tendency equation. In case of underproduction....... The method was implemented in the Danish Meteorological Institute numerical weather prediction (DMI NWP) nowcasting system, running with hourly cycles, performing a surface analysis and 3D variational analysis for upper air assimilation at each cycle restart, followed by nudging assimilation of precipitation...

  9. High-temperature plastic flow of a precipitation-hardened FeCoNiCr high entropy alloy

    Energy Technology Data Exchange (ETDEWEB)

    He, J.Y.; Wang, H.; Wu, Y.; Liu, X.J. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Nieh, T.G. [Department of Materials Science and Engineering, the University of Tennessee, Knoxville, TN 37996 (United States); Lu, Z.P., E-mail: luzhaoping@163.com [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)

    2017-02-16

    In this work, we systematically investigated flow behavior of a high entropy alloy (HEA) strengthened by coherent γ′ precipitates in the temperature range of 1023–1173 K. In contrast to the single-phase FeCoNiCrMn HEA, this precipitate-hardened alloy, i.e., (FeCoNiCr){sub 94}Ti{sub 2}Al{sub 4}, exhibited large reduction of the steady-state strain rate (by ~2 orders of magnitude) or drastic enhancement in flow stress, indicating significant improvement in high-temperature properties. Our results showed that the deformation could be divided into two regimes. At temperatures below 1123 K, coherent γ′ precipitates effectively blocked the dislocation motion, thus resulted in a threshold stress effect. Above 1123 K, however, γ′ particles dissolved and the deformation was controlled by the ordinary dislocation climb mechanism. In addition, we conducted transmission electron microscopy to characterize dislocation-precipitate interaction to provide microstructural evidences to support our conclusion of the specific deformation mechanisms in the two temperature regimes.

  10. The Relative Performance of High Resolution Quantitative Precipitation Estimates in the Russian River Basin

    Science.gov (United States)

    Bytheway, J. L.; Biswas, S.; Cifelli, R.; Hughes, M.

    2017-12-01

    The Russian River carves a 110 mile path through Mendocino and Sonoma counties in western California, providing water for thousands of residents and acres of agriculture as well as a home for several species of endangered fish. The Russian River basin receives almost all of its precipitation during the October through March wet season, and the systems bringing this precipitation are often impacted by atmospheric river events as well as the complex topography of the region. This study will examine the performance of several high resolution (hourly, products and forecasts over the 2015-2016 and 2016-2017 wet seasons. Comparisons of event total rainfall as well as hourly rainfall will be performed using 1) rain gauges operated by the National Oceanic and Atmospheric Administration (NOAA) Physical Sciences Division (PSD), 2) products from the Multi-Radar/Multi-Sensor (MRMS) QPE dataset, and 3) quantitative precipitation forecasts from the High Resolution Rapid Refresh (HRRR) model at 1, 3, 6, and 12 hour lead times. Further attention will be given to cases or locations representing large disparities between the estimates.

  11. High resolution SEM characterization of nano-precipitates in ODS steels.

    Science.gov (United States)

    Jóźwik, Iwona; Strojny-Nędza, Agata; Chmielewski, Marcin; Pietrzak, Katarzyna; Kurpaska, Łukasz; Nosewicz, Szymon

    2018-05-01

    The performance of the present-day scanning electron microscopy (SEM) extends far beyond delivering electronic images of the surface topography. Oxide dispersion strengthened (ODS) steel is on of the most promising materials for the future nuclear fusion reactor because of its good radiation resistance, and higher operation temperature up to 750°C. The microstructure of ODS should not exceed tens of nm, therefore there is a strong need in a fast and reliable technique for their characterization. In this work, the results of low-kV SEM characterization of nanoprecipitates formed in the ODS matrix are presented. Application of highly sensitive photo-diode BSE detector in SEM imaging allowed for the registration of single nm-sized precipitates in the vicinity of the ODS alloys. The composition of the precipitates has been confirmed by TEM-EDS. © 2018 Wiley Periodicals, Inc.

  12. Lipopolysaccharide precipitates hepatic encephalopathy and increases blood-brain barrier permeability in mice with acute liver failure.

    Science.gov (United States)

    Chastre, Anne; Bélanger, Mireille; Nguyen, Bich N; Butterworth, Roger F

    2014-03-01

    Acute liver failure (ALF) is frequently complicated by infection leading to precipitation of central nervous system complications such as hepatic encephalopathy (HE) and increased mortality. There is evidence to suggest that when infection occurs in ALF patients, the resulting pro-inflammatory mechanisms may be amplified that could, in turn, have a major impact on blood-brain barrier (BBB) function. The aim of this study was to investigate the role of endotoxemia on the progression of encephalopathy in relation to BBB permeability during ALF. Adult male C57-BL6 mice with ALF resulting from azoxymethane-induced toxic liver injury were administered trace amounts of the endotoxin component lipopolysaccharide (LPS). Effects on the magnitude of the systemic inflammatory response, liver pathology and BBB integrity were measured as a function of progression of HE, defined as time to loss of corneal reflex (coma). Lipopolysaccharide caused additional two- to seven-fold (P liver pathology and associated increases of circulating transaminases as well as increased hyperammonaemia consistent with a further loss of viable hepatocytes. LPS treatment of ALF mice led to a rapid precipitation of hepatic coma and the BBB became permeable to the 25-kDa protein immunoglobulin G (IgG). This extravasation of IgG was accompanied by ignificant up-regulation of matrix metalloproteinase-9 (MMP-9), an endopeptidase known to modulate opening of the BBB in a wide range of neurological disorders. These findings represent the first direct evidence of inflammation-related BBB permeability changes in ALF. © 2013 John Wiley & Sons A/S. Publishing by John Wiley & Sons Ltd.

  13. Altmetric: 165More detailArticle | OPENClimate change-induced increases in precipitation are reducing the potential for solar ultraviolet radiation to inactivate pathogens in surface waters

    Science.gov (United States)

    Climate change is accelerating the release of dissolved organic matter (DOM) to inland and coastal waters through increases in precipitation, thawing of permafrost, and changes in vegetation. Our modeling approach suggests that the selective absorption of ultraviolet radiation (U...

  14. Using High Energy Precipitation for Magnetic Mapping in the Nightside Transition Region During Dynamic Events

    Science.gov (United States)

    Spanswick, E.

    2017-12-01

    Identifying the magnetic footprint of a satellite can be done using the in situ observations together with some ionospheric or low-altitude satellite observation to argue that the two measurements were made on the same field line. Nishimura et al. [2011], e.g., correlated a time series of chorus wave power near the magnetic equator with the time series of intensities of every pixel of a is roughly magnetically conjugate ASI. Often, the pattern of correlation shows a well-defined peak at the location of the satellite's magnetic footprint. Their results cannot be replicated during dynamic events (e.g., substorms), because the required auroral forms do not occur at such times. It would be important if we could make mappings with such confidence during active times. The Transition Region Explorer (TREx), which is presently being implemented, is a new ground-based facility that will remote sense electron precipitation across 3 hours of MLT and 12 degrees of magnetic latitude spanning the auroral zone in western Canada. TREx includes the world's first imaging riometers array with a contiguous field of view large enough to seamlessly track the spatio-temporal evolution of high energy electron precipitation at mesoscales. Two studies motivated the TREx riometers array. First, Baker et al. [1981] demonstrated riometer absorption is an excellent proxy for the electron energy flux integrated from 30 keV to 200keV keV at the magnetic equator on the flux tube corresponding to the location of that riometers. Second, Spanswick et al. [2007] showed the correlation between the riometers absorption and the integrated electron energy flux near the magnetic equator peaked when the satellite was nearest to conjugate to the riometers. Here we present observations using CANOPUS single beam riometers and CRRES MEB to illustrate how the relative closeness of the footpoint of an equatorial spacecraft can be assessed using high energy precipitation. As well, we present the capabilities of

  15. Observational evidence of a long-term increase in precipitation due to urbanization effects and its implications for sustainable urban living.

    Science.gov (United States)

    Wai, K M; Wang, X M; Lin, T H; Wong, M S; Zeng, S K; He, N; Ng, E; Lau, K; Wang, D H

    2017-12-01

    Although projected precipitation increases in East Asia due to future climate change have aroused concern, less attention has been paid by the scientific community and public to the potential long-term increase in precipitation due to rapid urbanization. A ten-year precipitation dataset was analysed for both a rapidly urbanized megacity and nearby suburban/rural stations in southern China. Rapid urbanization in the megacity was evident from satellite observations. A statistically significant, long-term, increasing trend of precipitation existed only at the megacity station (45.6mm per decade) and not at the other stations. The increase was attributed to thermal and dynamical modifications of the tropospheric boundary layer related to urbanization, which was confirmed by the results of our WRF-SLUCM simulations. The results also suggested that a long-term regional increase in precipitation, caused by greenhouse gas-induced climate change, for instance, was not evident within the study period. The urbanization-induced increase was found to be higher than the precipitation increase (18.3mm per decade) expected from future climate change. The direct climate impacts due to rapid urbanization is highlighted with strong implications for urban sustainable development and the planning of effective adaptation strategies for issues such as coastal defenses, mosquito-borne disease spread and heat stress mortality. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. A Numerical Method to Generate High Temporal Resolution Precipitation Time Series by Combining Weather Radar Measurements with a Nowcast Model

    DEFF Research Database (Denmark)

    Nielsen, Jesper Ellerbæk; Thorndahl, Søren Liedtke; Rasmussen, Michael R.

    2014-01-01

    The topic of this paper is temporal interpolation of precipitation observed by weather radars. Precipitation measurements with high spatial and temporal resolution are, in general, desired for urban drainage applications. An advection-based interpolation method is developed which uses methods...

  17. An increase in precipitation exacerbates negative effects of nitrogen deposition on soil cations and soil microbial communities in a temperate forest.

    Science.gov (United States)

    Shi, Leilei; Zhang, Hongzhi; Liu, Tao; Mao, Peng; Zhang, Weixin; Shao, Yuanhu; Fu, Shenglei

    2018-04-01

    World soils are subjected to a number of anthropogenic global change factors. Although many previous studies contributed to understand how single global change factors affect soil properties, there have been few studies aimed at understanding how two naturally co-occurring global change drivers, nitrogen (N) deposition and increased precipitation, affect critical soil properties. In addition, most atmospheric N deposition and precipitation increase studies have been simulated by directly adding N solution or water to the forest floor, and thus largely neglect some key canopy processes in natural conditions. These previous studies, therefore, may not realistically simulate natural atmospheric N deposition and precipitation increase in forest ecosystems. In a field experiment, we used novel canopy applications to investigate the effects of N deposition, increased precipitation, and their combination on soil chemical properties and the microbial community in a temperate deciduous forest. We found that both soil chemistry and microorganisms were sensitive to these global change factors, especially when they were simultaneously applied. These effects were evident within 2 years of treatment initiation. Canopy N deposition immediately accelerated soil acidification, base cation depletion, and toxic metal accumulation. Although increased precipitation only promoted base cation leaching, this exacerbated the effects of N deposition. Increased precipitation decreased soil fungal biomass, possible due to wetting/re-drying stress or to the depletion of Na. When N deposition and increased precipitation occurred together, soil gram-negative bacteria decreased significantly, and the community structure of soil bacteria was altered. The reduction of gram-negative bacterial biomass was closely linked to the accumulation of the toxic metals Al and Fe. These results suggested that short-term responses in soil cations following N deposition and increased precipitation could change

  18. Geo-statistical model of Rainfall erosivity by using high temporal resolution precipitation data in Europe

    Science.gov (United States)

    Panagos, Panos; Ballabio, Cristiano; Borrelli, Pasquale; Meusburger, Katrin; Alewell, Christine

    2015-04-01

    Rainfall erosivity (R-factor) is among the 6 input factors in estimating soil erosion risk by using the empirical Revised Universal Soil Loss Equation (RUSLE). R-factor is a driving force for soil erosion modelling and potentially can be used in flood risk assessments, landslides susceptibility, post-fire damage assessment, application of agricultural management practices and climate change modelling. The rainfall erosivity is extremely difficult to model at large scale (national, European) due to lack of high temporal resolution precipitation data which cover long-time series. In most cases, R-factor is estimated based on empirical equations which take into account precipitation volume. The Rainfall Erosivity Database on the European Scale (REDES) is the output of an extensive data collection of high resolution precipitation data in the 28 Member States of the European Union plus Switzerland taking place during 2013-2014 in collaboration with national meteorological/environmental services. Due to different temporal resolutions of the data (5, 10, 15, 30, 60 minutes), conversion equations have been applied in order to homogenise the database at 30-minutes interval. The 1,541 stations included in REDES have been interpolated using the Gaussian Process Regression (GPR) model using as covariates the climatic data (monthly precipitation, monthly temperature, wettest/driest month) from WorldClim Database, Digital Elevation Model and latitude/longitude. GPR has been selected among other candidate models (GAM, Regression Kriging) due the best performance both in cross validation (R2=0.63) and in fitting dataset (R2=0.72). The highest uncertainty has been noticed in North-western Scotland, North Sweden and Finland due to limited number of stations in REDES. Also, in highlands such as Alpine arch and Pyrenees the diversity of environmental features forced relatively high uncertainty. The rainfall erosivity map of Europe available at 500m resolution plus the standard error

  19. Precipitation in Al–Mg solid solution prepared by solidification under high pressure

    International Nuclear Information System (INIS)

    Jie, J.C.; Wang, H.W.; Zou, C.M.; Wei, Z.J.; Li, T.J.

    2014-01-01

    The precipitation in Al–Mg solid solution containing 21.6 at.% Mg prepared by solidification under 2 GPa was investigated. The results show that the γ-Al 12 Mg 17 phase is formed and the β′ phase cannot be observed in the solid solution during ageing process. The precipitation of γ and β phases takes place in a non-uniform manner during heating process, i.e. the γ and β phases are first formed in the interdendritic region, which is caused by the inhomogeneous distribution of Mg atoms in the solid solution solidified under high pressure. Peak splitting of X-ray diffraction patterns of Al(Mg) solid solution appears, and then disappears when the samples are aged at 423 K for different times, due to the non-uniform precipitation in Al–Mg solid solution. The direct transformation from the γ to β phase is observed after ageing at 423 K for 24 h. It is considered that the β phase is formed through a peritectoid reaction of α + γ → β which needs the diffusion of Mg atoms across the interface of α/γ phases. - Highlights: • The γ phase is formed and the β′ phase is be observed in Al(Mg) solid solution. • Peak splitting of XRD pattern of Al(Mg) solid solution appears during aged at 150 °C. • The β phase is formed through a peritectoid reaction of α + γ → β

  20. Precipitation Strengthenable NiTiPd High Temperature Shape Memory Alloys

    Science.gov (United States)

    Bigelow, Glen; Garg, Anita; Benafan, Othmane; Noebe, Ronald; Gaydosh, Darrell; Padula, Santo, II

    2017-01-01

    In binary NiTi alloys, it has long been known that Ni-rich alloys can be heat treated to produce precipitates which both strengthen the matrix against dislocations and improve the behavior of the material under thermal and mechanical cycling. Within recent years, the same effect has been observed in Ni-rich NiTiHf high temperature shape memory alloys and heat treatment regimens have been defined which will reliably produce improved properties. In NiTiPd alloys, precipitation has also been observed, but studies are still underway to define reliable heat treatments and compositions which will provide a balance of strengthening and good thermomechanical properties. For this study, a series of NiTi-32 at.Pd alloys was produced to determine the effect of changing nickeltitanium content on the transformation behavior and heat treatability of the material. Samples were aged at temperatures between 350C and 450C for times up to 100 hours. Actuation type behavior was evaluated using uniaxial constant force thermal cycling (UCFTC) to determine the effect of composition and aging on the material behavior. TEMSEM was used to evaluate the microstructure and determine the types of precipitates formed. The correlation between composition, heat treat, microstructure, and thermomechanical behavior will be addressed and discussed.

  1. Precipitation in solid solution and structural transformations in single crystals of high rhenium ruthenium-containing nickel superalloys at high-temperature creep

    Energy Technology Data Exchange (ETDEWEB)

    Alekseev, A.A.; Petrushin, N.V.; Zaitsev, D.V.; Treninkov, I.A.; Filonova, E.V. [All-Russian Scientific Research Institute of Aviation Materials (VIAM), Moscow (Russian Federation)

    2010-07-01

    The phase composition and structure of single crystals of two superalloys (alloy 1 and alloy 2) were investigated in this work. For alloy 1 (Re - 9 wt%) the kinetics of precipitation in solid solution at heat treatment (HT) was investigated. TEM and X-Ray examinations have revealed that during HT rhombic phase (R-phase) precipitation (Immm class (BCR)) occurs. The TTT diagram is plotted, it contains the time-temperature area of the existence of R-phase particles. The element content of R-phase is identified (at. %): Re- 51.5; Co- 23.5; Cr- 14.8; Mo- 4.2; W- 3.3; Ta- 2.7. For alloy 2 (Re - 6.5 wt %, Ru - 4 wt %) structural transformations at high-temperature creep are investigated. By dark-field TEM methods it is established, that in alloy 2 the additional phase with a rhombic lattice is formed during creep. Particles of this phase precipitate in {gamma}-phase and their quantity increases during high-temperature creep. It is revealed that during creep 3-D dislocation network is formed in {gamma}-phase. At the third stage of creep the process of inversion structure formation is observed in the alloy, i.e. {gamma}'-phase becomes a matrix. Thus during modeling creep the volume fraction of {gamma}'-phase in the samples increases from 30% (at creep duration of 200 hrs) up to 55% (at 500 hrs). The processes of structure formation in Re and Ru-containing nickel superalloys are strongly affected by decomposition of solid solution during high-temperature creep that includes precipitation of additional TCP-phases. (orig.)

  2. Effect of nano-sized precipitates on the crystallography of ferrite in high-strength strip steel

    Institute of Scientific and Technical Information of China (English)

    Jing-jing Yang; Run Wu; Wen Liang; Meng-xia Tang

    2014-01-01

    For strip steel with the thickness of 1.6 mm, the yield and tensile strengths as high as 760 and 850 MPa, respectively, were achieved using the compact strip production technology. Precipitates in the steel were characterized by scanning and transmission electron microscopy to elucidate the strengthening mechanism. In addition, intragranular misorientation, Kernel average misorientation, and stored energy were measured using electron backscatter diffraction for crystallographic analysis of ferrite grains containing precipitates and their neighbors without precipitates. It is found that precipitates in specimens primarily consist of TiC and Ti4C2S2. Ferrite grains containing pre-cipitates exhibit the high Taylor factor as well as the crystallographic orientations with{012},{011},{112}, or{221}plane parallel to the rolling plane. Compared with the intragranular orientation of adjoining grains, the intragranular misorientation of grains containing precipi-tates fluctuates more frequently and more mildly as a function of distance. Moreover, the precipitates can induce ferrite grains to store a rela-tively large amount of energy. These results suggest that a correlation exists between precipitation in ferrite grains and grain crystallographic properties.

  3. Estimates of increased black carbon emissions from electrostatic precipitators during powdered activated carbon injection for mercury emissions control.

    Science.gov (United States)

    Clack, Herek L

    2012-07-03

    The behavior of mercury sorbents within electrostatic precipitators (ESPs) is not well-understood, despite a decade or more of full-scale testing. Recent laboratory results suggest that powdered activated carbon exhibits somewhat different collection behavior than fly ash in an ESP and particulate filters located at the outlet of ESPs have shown evidence of powdered activated carbon penetration during full-scale tests of sorbent injection for mercury emissions control. The present analysis considers a range of assumed differential ESP collection efficiencies for powdered activated carbon as compared to fly ash. Estimated emission rates of submicrometer powdered activated carbon are compared to estimated emission rates of particulate carbon on submicrometer fly ash, each corresponding to its respective collection efficiency. To the extent that any emitted powdered activated carbon exhibits size and optical characteristics similar to black carbon, such emissions could effectively constitute an increase in black carbon emissions from coal-based stationary power generation. The results reveal that even for the low injection rates associated with chemically impregnated carbons, submicrometer particulate carbon emissions can easily double if the submicrometer fraction of the native fly ash has a low carbon content. Increasing sorbent injection rates, larger collection efficiency differentials as compared to fly ash, and decreasing sorbent particle size all lead to increases in the estimated submicrometer particulate carbon emissions.

  4. A Radar Climatology for Germany - a 16-year high resolution precipitation data and its possibilities

    Science.gov (United States)

    Walawender, Ewelina; Winterrath, Tanja; Brendel, Christoph; Hafer, Mario; Junghänel, Thomas; Klameth, Anna; Weigl, Elmar; Becker, Andreas

    2017-04-01

    One of the main features of heavy precipitation events is their small-scale distribution. Despite a local occurrence, these intensive rainfalls may, however, cause most serious damage and have significant impact on the whole river basin area resulting in e.g. flash floods or urban flooding. Thus, it is of great importance not only to detect the life-cycle of extreme precipitation during its occurrence but also to collect precise climatological information on such events. The German weather service (Deutscher Wetterdienst) operates a very dense network of more than 2000 weather stations collecting data on precipitation. It is however not sufficient for detecting spatially limited phenomena. Thanks to radar data, current monitoring of such events is possible. A quality control process is applied to real-time radar products, however only automatic rain gauges data can be used in the adjustment procedure. To merge both radar data and all available rain gauges data, the radar climatology dataset was established. Within the framework of a project financed by the federal agencies' strategic alliance 'Adaptation to Climate Change', 16 years (2001-2016) of radar data have been reanalyzed in order to gain a homogenous, quality-controlled, high-resolution precipitation data set suitable for analyzing extreme events in a climatological approach. Additional corrections methods (e.g. clutter, spokes and beam height correction) were defined and used for the reprocessing procedure to enhance the data quality. Although the time series is still rather short for a climatology, for the first time the data set allows an insight into e.g. the distribution, size, life cycle, and duration of extreme events that cannot be measured by point measurements alone. All radar climatology products share the same spatial and temporal coverage. The whole dataset has been produced for the area of Germany. With the relatively high spatial resolution of 1km, the data can be used as a component of wide

  5. Response of solute and precipitation-strengthened copper alloys at high neutron exposure

    International Nuclear Information System (INIS)

    Garner, F.A.; Hamilton, M.L.; Shikama, T.; Edwards, D.J.; Newkirk, J.W.

    1991-11-01

    A variety of solute and precipitation strengthened copper base alloys have been irradiated to neutron-induced displacement levels of 34 to 150 dpa at 415 degrees C and 32 dpa at 529 degrees C in the Fast Flux Test Facility to assess their potential for high heat flux applications in fusion reactors. Several MZC-type alloys appear to offer the most promise for further study. For low fluence applications CuBeNi and spinodally strengthened CuNiTi alloys may also be suitable. Although Cu-2Be resists swelling, it is not recommended for fusion reactor applications because of its low conductivity

  6. Response of solute and precipitation-strengthened copper alloys at high neutron exposure

    Energy Technology Data Exchange (ETDEWEB)

    Garner, F.A.; Hamilton, M.L. [Pacific Northwest Lab., Richland, WA (United States); Shikama, T. [Tohoku Univ., Oarai Branch (Japan); Edwards, D.J.; Newkirk, J.W. [Missouri Univ., Rolla, MO (United States)

    1991-11-01

    A variety of solute and precipitation strengthened copper base alloys have been irradiated to neutron-induced displacement levels of 34 to 150 dpa at 415{degrees}C and 32 dpa at 529{degrees}C in the Fast Flux Test Facility to assess their potential for high heat flux applications in fusion reactors. Several MZC-type alloys appear to offer the most promise for further study. For low fluence applications CuBeNi and spinodally strengthened CuNiTi alloys may also be suitable. Although Cu-2Be resists swelling, it is not recommended for fusion reactor applications because of its low conductivity.

  7. Synthesis of high purity tungsten nanoparticles from tungsten heavy alloy scrap by selective precipitation and reduction route

    International Nuclear Information System (INIS)

    Kamal, S.S. Kalyan; Sahoo, P.K.; Vimala, J.; Shanker, B.; Ghosal, P.; Durai, L.

    2016-01-01

    In this paper we report synthesis of tungsten nanoparticles of high purity >99.7 wt% from heavy alloy scrap using a novel chemical route of selective precipitation and reduction. The effect of Poly(vinylpyrrolidone) polymer on controlling the particle size is established through FTIR spectra and corroborated with TEM images, wherein the average size decreased form 210 to 45 nm with increasing PVP content from zero to 2 g under different experimental conditions. This process is economical as raw material is a scrap and the efficiency of the reaction is >95%. - Highlights: • Tungsten nanoparticles were synthesized from tungsten heavy alloy scrap. • A novel chemical route of precipitation and reduction with Poly(vinylpyrrolidone) polymer as stabilizer is reported. • The average size decreased form 210 to 45 nm with increasing PVP content from zero to 2 g. • High pure tungsten nanoparticles of >99.7% purity could be synthesized using this route. • Efficiency of the reaction is >95%.

  8. Precipitous Birth

    Directory of Open Access Journals (Sweden)

    Jennifer Yee

    2017-09-01

    Full Text Available Audience: This scenario was developed to educate emergency medicine residents on the management of a precipitous birth in the emergency department (ED. The case is also appropriate for teaching of medical students and advanced practice providers, as well as reviewing the principles of crisis resource management, teamwork, and communication. Introduction: Patients with precipitous birth require providers to manage two patients simultaneously with limited time and resources. Crisis resource management skills will be tested once baby is delivered, and the neonate will require assessment for potential neonatal resuscitation. Objectives: At the conclusion of the simulation session, learners will be able to manage women who have precipitous deliveries, as well as perform neonatal assessment and management. Method: This session was conducted using high-fidelity simulation, followed by a debriefing session and lecture on precipitous birth management and neonatal evaluation.

  9. TEM investigation of aluminium containing precipitates in high aluminium doped silicon carbide

    International Nuclear Information System (INIS)

    Wong-Leung, J.; FitzGerald, J.D.

    2002-01-01

    Full text: Silicon carbide is a promising semiconductor material for applications in high temperature and high power devices. The successful growth of good quality epilayers in this material has enhanced its potential for device applications. As a novel semiconductor material, there is a need for studying its basic physical properties and the role of dopants in this material. In this study, silicon carbide epilayers were grown on 4H-SiC wafers of (0001) orientation with a miscut angle of 8 deg at a temperature of 1550 deg C. The epilayers contained regions of high aluminium doping well above the solubility of aluminium in silicon carbide. High temperature annealing of this material resulted in the precipitation of aluminium in the wafers. The samples were analysed by secondary ion mass spectrometry and transmission electron microscopy. Selected area diffraction studies show the presence of aluminium carbide and aluminium silicon carbide phases. Copyright (2002) Australian Society for Electron Microscopy Inc

  10. Nanocharacterisation of precipitates in austenite high manganese steels with advanced techniques: HRSTEM and DualEELS mapping

    International Nuclear Information System (INIS)

    Bobynko, J; Craven, A J; McGrouther, D; MacLaren, I; Paul, G

    2014-01-01

    To achieve optimal mechanical properties in high manganese steels, the precipitation of nanoprecipitates of vanadium and niobium carbides is under investigation. It is shown that under controlled heat treatments between 850°C and 950°C following hot deformation, few-nanometre precipitates of either carbide can be produced in test steels with suitable contents of vanadium or niobium. The structure and chemistry of these precipitates are examined in detail with a spatial resolution down to better than 1 nm using a newly commissioned scanning transmission electron microscope. In particular, it is shown that the nucleation of vanadium carbide precipitates often occurs at pre-existing titanium carbide precipitates which formed from titanium impurities in the bulk steel. This work will also highlight the links between the nanocharacterisation and changes in the bulk properties on annealing

  11. High-resolution Monthly Satellite Precipitation Product over the Conterminous United States

    Science.gov (United States)

    Hashemi, H.; Fayne, J.; Knight, R. J.; Lakshmi, V.

    2017-12-01

    We present a data set that enhanced the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) monthly product 3B43 in its accuracy and spatial resolution. For this, we developed a correction function to improve the accuracy of TRMM 3B43, spatial resolution of 25 km, by estimating and removing the bias in the satellite data using a ground-based precipitation data set. We observed a strong relationship between the bias and land surface elevation; TRMM 3B43 tends to underestimate the ground-based product at elevations above 1500 m above mean sea level (m.amsl) over the conterminous United States. A relationship was developed between satellite bias and elevation. We then resampled TRMM 3B43 to the Digital Elevation Model (DEM) data set at a spatial resolution of 30 arc second ( 1 km on the ground). The produced high-resolution satellite-based data set was corrected using the developed correction function based on the bias-elevation relationship. Assuming that each rain gauge represents an area of 1 km2, we verified our product against 9,200 rain gauges across the conterminous United States. The new product was compared with the gauges, which have 50, 60, 70, 80, 90, and 100% temporal coverage within the TRMM period of 1998 to 2015. Comparisons between the high-resolution corrected satellite-based data and gauges showed an excellent agreement. The new product captured more detail in the changes in precipitation over the mountainous region than the original TRMM 3B43.

  12. PRECIPITATION BEHAVIOR OF M2N IN A HIGH-NITROGEN AUSTENITIC STAINLESS STEEL DURING ISOTHERMAL AGING

    Institute of Scientific and Technical Information of China (English)

    F. Shi; L.J. Wang; W.F. Cui; C.M. Liu

    2007-01-01

    The precipitation behavior of M2N and the microstructural evolution in a Cr-Mn austenitic stainless steel with a high nitrogen content of 0.43mass% during isothermal aging has been investigated using optical microscopy (OM), scanning electron microscopy ( SEM), and transmission electron microscopy (TEM). The aging treatments have led to the decomposition of nitrogen supersaturated austenitic matrix through discontinuous cellular precipitation. The precipitated cells comprise alternate lamellae of M2N precipitate and austenitic matrix. This kind of precipitate morphology is similar to that of pearlite. However, owing to the non-eutectoidic mechanism of the reaction, the growth characteristic of the cellular precipitates is different from that of pearlite in Fe-C binary alloys. M2N precipitate in the cell possesses a hexagonal crystal structure with the parameters a=0.4752nm and c=0.4429nm, and the orientation relationship between the MN precipitates and austenite determined from the SADP is [01110]M2N// [101]γ,[2-1-10]M2N// [010]γ.

  13. Five hundred years of gridded high-resolution precipitation reconstructions over Europe and the connection to large-scale circulation

    Energy Technology Data Exchange (ETDEWEB)

    Pauling, Andreas [University of Bern, Institute of Geography, Bern (Switzerland); Luterbacher, Juerg; Wanner, Heinz [University of Bern, Institute of Geography, Bern (Switzerland); National Center of Competence in Research (NCCR) in Climate, Bern (Switzerland); Casty, Carlo [University of Bern, Climate and Environmental Physics Institute, Bern (Switzerland)

    2006-03-15

    We present seasonal precipitation reconstructions for European land areas (30 W to 40 E/30-71 N; given on a 0.5 x 0.5 resolved grid) covering the period 1500-1900 together with gridded reanalysis from 1901 to 2000 (Mitchell and Jones 2005). Principal component regression techniques were applied to develop this dataset. A large variety of long instrumental precipitation series, precipitation indices based on documentary evidence and natural proxies (tree-ring chronologies, ice cores, corals and a speleothem) that are sensitive to precipitation signals were used as predictors. Transfer functions were derived over the 1901-1983 calibration period and applied to 1500-1900 in order to reconstruct the large-scale precipitation fields over Europe. The performance (quality estimation based on unresolved variance within the calibration period) of the reconstructions varies over centuries, seasons and space. Highest reconstructive skill was found for winter over central Europe and the Iberian Peninsula. Precipitation variability over the last half millennium reveals both large interannual and decadal fluctuations. Applying running correlations, we found major non-stationarities in the relation between large-scale circulation and regional precipitation. For several periods during the last 500 years, we identified key atmospheric modes for southern Spain/northern Morocco and central Europe as representations of two precipitation regimes. Using scaled composite analysis, we show that precipitation extremes over central Europe and southern Spain are linked to distinct pressure patterns. Due to its high spatial and temporal resolution, this dataset allows detailed studies of regional precipitation variability for all seasons, impact studies on different time and space scales, comparisons with high-resolution climate models as well as analysis of connections with regional temperature reconstructions. (orig.)

  14. Exposure to extreme heat and precipitation events associated with increased risk of hospitalization for asthma in Maryland, U.S.A.

    Science.gov (United States)

    Soneja, Sutyajeet; Jiang, Chengsheng; Fisher, Jared; Upperman, Crystal Romeo; Mitchell, Clifford; Sapkota, Amir

    2016-04-27

    Several studies have investigated the association between asthma exacerbations and exposures to ambient temperature and precipitation. However, limited data exists regarding how extreme events, projected to grow in frequency, intensity, and duration in the future in response to our changing climate, will impact the risk of hospitalization for asthma. The objective of our study was to quantify the association between frequency of extreme heat and precipitation events and increased risk of hospitalization for asthma in Maryland between 2000 and 2012. We used a time-stratified case-crossover design to examine the association between exposure to extreme heat and precipitation events and risk of hospitalization for asthma (ICD-9 code 493, n = 115,923). Occurrence of extreme heat events in Maryland increased the risk of same day hospitalization for asthma (lag 0) by 3 % (Odds Ratio (OR): 1.03, 95 % Confidence Interval (CI): 1.00, 1.07), with a considerably higher risk observed for extreme heat events that occur during summer months (OR: 1.23, 95 % CI: 1.15, 1.33). Likewise, summertime extreme precipitation events increased the risk of hospitalization for asthma by 11 % in Maryland (OR: 1.11, 95 % CI: 1.06, 1.17). Across age groups, increase in risk for asthma hospitalization from exposure to extreme heat event during the summer months was most pronounced among youth and adults, while those related to extreme precipitation event was highest among ≤4 year olds. Exposure to extreme heat and extreme precipitation events, particularly during summertime, is associated with increased risk of hospitalization for asthma in Maryland. Our results suggest that projected increases in frequency of extreme heat and precipitation event will have significant impact on public health.

  15. APES: Acute Precipitating Electron Spectrometer - A High Time Resolution Monodirectional Magnetic Deflection Electron Spectrometer

    Science.gov (United States)

    Michell, R. G.; Samara, M.; Grubbs, G., II; Ogasawara, K.; Miller, G.; Trevino, J. A.; Webster, J.; Stange, J.

    2016-01-01

    We present a description of the Acute Precipitating Electron Spectrometer (APES) that was designed and built for the Ground-to-Rocket Electron Electrodynamics Correlative Experiment (GREECE) auroral sounding rocket mission. The purpose was to measure the precipitating electron spectrum with high time resolution, on the order of milliseconds. The trade-off made in order to achieve high time resolution was to limit the aperture to only one look direction. The energy selection was done by using a permanent magnet to separate the incoming electrons, such that the different energies would fall onto different regions of the microchannel plate and therefore be detected by different anodes. A rectangular microchannel plate (MCP) was used (15 mm x 100 mm), and there was a total of 50 discrete anodes under the MCP, each one 15 mm x 1.5 mm, with a 0.5 mm spacing between anodes. The target energy range of APES was 200 eV to 30 keV.

  16. Separation of aromatic precipitates from simulated high level radioactive waste by hydrolysis, evaporation and liquid-liquid extraction

    International Nuclear Information System (INIS)

    Young, S.R.; Shah, H.B.; Carter, J.T.

    1991-01-01

    The Defense Waste Processing Facility (DWPF) at the SRS will be the United States' first facility to process High Level radioactive Waste (HLW) into a borosilicate glass matrix. The removal of aromatic precipitates by hydrolysis, evaporation and liquid-liquid extraction will be a key step in the processing of the HLW. This step, titled the Precipitate Hydrolysis Process, has been demonstrated by the Savannah River Laboratory with the Precipitate Hydrolysis Experimental Facility (PHEF). The mission of the PHEF is to demonstrate processing of simulated high level radioactive waste which contains tetraphenylborate precipitates and nitrite. Reduction of nitrite by hydroxylamine nitrate and hydrolysis of the tetraphenylborate by formic acid is discussed. Gaseous production, which is primarily benzene, nitrous oxide and carbon dioxide, has been quantified. Production of high-boiling organic compounds and the accumulation of these organic compounds within the process are addressed

  17. Predicting abundance and variability of ice nucleating particles in precipitation at the high-altitude observatory Jungfraujoch

    Directory of Open Access Journals (Sweden)

    E. Stopelli

    2016-07-01

    Full Text Available Nucleation of ice affects the properties of clouds and the formation of precipitation. Quantitative data on how ice nucleating particles (INPs determine the distribution, occurrence and intensity of precipitation are still scarce. INPs active at −8 °C (INPs−8 were observed for 2 years in precipitation samples at the High-Altitude Research Station Jungfraujoch (Switzerland at 3580 m a.s.l. Several environmental parameters were scanned for their capability to predict the observed abundance and variability of INPs−8. Those singularly presenting the best correlations with observed number of INPs−8 (residual fraction of water vapour, wind speed, air temperature, number of particles with diameter larger than 0.5 µm, season, and source region of particles were implemented as potential predictor variables in statistical multiple linear regression models. These models were calibrated with 84 precipitation samples collected during the first year of observations; their predictive power was successively validated on the set of 15 precipitation samples collected during the second year. The model performing best in calibration and validation explains more than 75 % of the whole variability of INPs−8 in precipitation and indicates that a high abundance of INPs−8 is to be expected whenever high wind speed coincides with air masses having experienced little or no precipitation prior to sampling. Such conditions occur during frontal passages, often accompanied by precipitation. Therefore, the circumstances when INPs−8 could be sufficiently abundant to initiate the ice phase in clouds may frequently coincide with meteorological conditions favourable to the onset of precipitation events.

  18. Tree Rings Show Recent High Summer-Autumn Precipitation in Northwest Australia Is Unprecedented within the Last Two Centuries.

    Directory of Open Access Journals (Sweden)

    Alison J O'Donnell

    Full Text Available An understanding of past hydroclimatic variability is critical to resolving the significance of recent recorded trends in Australian precipitation and informing climate models. Our aim was to reconstruct past hydroclimatic variability in semi-arid northwest Australia to provide a longer context within which to examine a recent period of unusually high summer-autumn precipitation. We developed a 210-year ring-width chronology from Callitris columellaris, which was highly correlated with summer-autumn (Dec-May precipitation (r = 0.81; 1910-2011; p < 0.0001 and autumn (Mar-May self-calibrating Palmer drought severity index (scPDSI, r = 0.73; 1910-2011; p < 0.0001 across semi-arid northwest Australia. A linear regression model was used to reconstruct precipitation and explained 66% of the variance in observed summer-autumn precipitation. Our reconstruction reveals inter-annual to multi-decadal scale variation in hydroclimate of the region during the last 210 years, typically showing periods of below average precipitation extending from one to three decades and periods of above average precipitation, which were often less than a decade. Our results demonstrate that the last two decades (1995-2012 have been unusually wet (average summer-autumn precipitation of 310 mm compared to the previous two centuries (average summer-autumn precipitation of 229 mm, coinciding with both an anomalously high frequency and intensity of tropical cyclones in northwest Australia and the dominance of the positive phase of the Southern Annular Mode.

  19. Tree Rings Show Recent High Summer-Autumn Precipitation in Northwest Australia Is Unprecedented within the Last Two Centuries

    Science.gov (United States)

    O'Donnell, Alison J.; Cook, Edward R.; Palmer, Jonathan G.; Turney, Chris S. M.; Page, Gerald F. M.; Grierson, Pauline F.

    2015-01-01

    An understanding of past hydroclimatic variability is critical to resolving the significance of recent recorded trends in Australian precipitation and informing climate models. Our aim was to reconstruct past hydroclimatic variability in semi-arid northwest Australia to provide a longer context within which to examine a recent period of unusually high summer-autumn precipitation. We developed a 210-year ring-width chronology from Callitris columellaris, which was highly correlated with summer-autumn (Dec–May) precipitation (r = 0.81; 1910–2011; p < 0.0001) and autumn (Mar–May) self-calibrating Palmer drought severity index (scPDSI, r = 0.73; 1910–2011; p < 0.0001) across semi-arid northwest Australia. A linear regression model was used to reconstruct precipitation and explained 66% of the variance in observed summer-autumn precipitation. Our reconstruction reveals inter-annual to multi-decadal scale variation in hydroclimate of the region during the last 210 years, typically showing periods of below average precipitation extending from one to three decades and periods of above average precipitation, which were often less than a decade. Our results demonstrate that the last two decades (1995–2012) have been unusually wet (average summer-autumn precipitation of 310 mm) compared to the previous two centuries (average summer-autumn precipitation of 229 mm), coinciding with both an anomalously high frequency and intensity of tropical cyclones in northwest Australia and the dominance of the positive phase of the Southern Annular Mode. PMID:26039148

  20. SPREAD: a high-resolution daily gridded precipitation dataset for Spain – an extreme events frequency and intensity overview

    Directory of Open Access Journals (Sweden)

    R. Serrano-Notivoli

    2017-09-01

    Full Text Available A high-resolution daily gridded precipitation dataset was built from raw data of 12 858 observatories covering a period from 1950 to 2012 in peninsular Spain and 1971 to 2012 in Balearic and Canary islands. The original data were quality-controlled and gaps were filled on each day and location independently. Using the serially complete dataset, a grid with a 5 × 5 km spatial resolution was constructed by estimating daily precipitation amounts and their corresponding uncertainty at each grid node. Daily precipitation estimations were compared to original observations to assess the quality of the gridded dataset. Four daily precipitation indices were computed to characterise the spatial distribution of daily precipitation and nine extreme precipitation indices were used to describe the frequency and intensity of extreme precipitation events. The Mediterranean coast and the Central Range showed the highest frequency and intensity of extreme events, while the number of wet days and dry and wet spells followed a north-west to south-east gradient in peninsular Spain, from high to low values in the number of wet days and wet spells and reverse in dry spells. The use of the total available data in Spain, the independent estimation of precipitation for each day and the high spatial resolution of the grid allowed for a precise spatial and temporal assessment of daily precipitation that is difficult to achieve when using other methods, pre-selected long-term stations or global gridded datasets. SPREAD dataset is publicly available at https://doi.org/10.20350/digitalCSIC/7393.

  1. Effect of high-temperature pre-precipitation on microstructure and properties of 7055 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    陈康华; 黄兰萍

    2003-01-01

    The near-solvus pre-precipitation following higher temperature solution treatment was performed on 7055 aluminum alloy. The effect of the pre-precipitation on the microstructure, age hardening and stress corrosion cracking of 7055 alloy was investigated. The optical and transmission electron microscopy results show that the near-solvus pre-precipitation can be limited to grain boundary and enhance the discontinuity of grain boundary precipitates in the sequent age. The stress corrosion cracking resistance of aged 7055 alloys could be improved with non-deteriorated strength and plasticity via the pre-precipitation.

  2. High-resolution precipitation data derived from dynamical downscaling using the WRF model for the Heihe River Basin, northwest China

    Science.gov (United States)

    Zhang, Xuezhen; Xiong, Zhe; Zheng, Jingyun; Ge, Quansheng

    2018-02-01

    The community of climate change impact assessments and adaptations research needs regional high-resolution (spatial) meteorological data. This study produced two downscaled precipitation datasets with spatial resolutions of as high as 3 km by 3 km for the Heihe River Basin (HRB) from 2011 to 2014 using the Weather Research and Forecast (WRF) model nested with Final Analysis (FNL) from the National Center for Environmental Prediction (NCEP) and ERA-Interim from the European Centre for Medium-Range Weather Forecasts (ECMWF) (hereafter referred to as FNLexp and ERAexp, respectively). Both of the downscaling simulations generally reproduced the observed spatial patterns of precipitation. However, users should keep in mind that the two downscaled datasets are not exactly the same in terms of observations. In comparison to the remote sensing-based estimation, the FNLexp produced a bias of heavy precipitation centers. In comparison to the ground gauge-based measurements, for the warm season (May to September), the ERAexp produced more precipitation (root-mean-square error (RMSE) = 295.4 mm, across the 43 sites) and more heavy rainfall days, while the FNLexp produced less precipitation (RMSE = 115.6 mm) and less heavy rainfall days. Both the ERAexp and FNLexp produced considerably more precipitation for the cold season (October to April) with RMSE values of 119.5 and 32.2 mm, respectively, and more heavy precipitation days. Along with simulating a higher number of heavy precipitation days, both the FNLexp and ERAexp also simulated stronger extreme precipitation. Sensitivity experiments show that the bias of these simulations is much more sensitive to micro-physical parameterizations than to the spatial resolution of topography data. For the HRB, application of the WSM3 scheme may improve the performance of the WRF model.

  3. High Temperature Deformation Mechanism in Hierarchical and Single Precipitate Strengthened Ferritic Alloys by In Situ Neutron Diffraction Studies.

    Science.gov (United States)

    Song, Gian; Sun, Zhiqian; Li, Lin; Clausen, Bjørn; Zhang, Shu Yan; Gao, Yanfei; Liaw, Peter K

    2017-04-07

    The ferritic Fe-Cr-Ni-Al-Ti alloys strengthened by hierarchical-Ni 2 TiAl/NiAl or single-Ni 2 TiAl precipitates have been developed and received great attentions due to their superior creep resistance, as compared to conventional ferritic steels. Although the significant improvement of the creep resistance is achieved in the hierarchical-precipitate-strengthened ferritic alloy, the in-depth understanding of its high-temperature deformation mechanisms is essential to further optimize the microstructure and mechanical properties, and advance the development of the creep resistant materials. In the present study, in-situ neutron diffraction has been used to investigate the evolution of elastic strain of constitutive phases and their interactions, such as load-transfer/load-relaxation behavior between the precipitate and matrix, during tensile deformation and stress relaxation at 973 K, which provide the key features in understanding the governing deformation mechanisms. Crystal-plasticity finite-element simulations were employed to qualitatively compare the experimental evolution of the elastic strain during tensile deformation at 973 K. It was found that the coherent elastic strain field in the matrix, created by the lattice misfit between the matrix and precipitate phases for the hierarchical-precipitate-strengthened ferritic alloy, is effective in reducing the diffusional relaxation along the interface between the precipitate and matrix phases, which leads to the strong load-transfer capability from the matrix to precipitate.

  4. Studying of Nano SiO2 Preparation from Rice Husk Ash by Using High Gravity Reaction Precipitation Technology

    International Nuclear Information System (INIS)

    Nguyen Thanh Chung; Tran Ngoc Ha; Hoang Van Duc

    2013-01-01

    A novel method (High-gravity reactive precipitation - HGRP) was developed to prepare nano-SiO 2 from rice husk ash using gas-liquid reaction system. The precipitated silica produced by our proposed method had average size of 20 nm with narrow size distribution and purity of SiO 2 was approximately 99.2%. The principles of the method as well as experimental conditions were also described. (author)

  5. High cloud variations with surface temperature from 2002 to 2015: Contributions to atmospheric radiative cooling rate and precipitation changes

    Science.gov (United States)

    Liu, Run; Liou, Kuo-Nan; Su, Hui; Gu, Yu; Zhao, Bin; Jiang, Jonathan H.; Liu, Shaw Chen

    2017-05-01

    The global mean precipitation is largely constrained by atmospheric radiative cooling rates (Qr), which are sensitive to changes in high cloud fraction. We investigate variations of high cloud fraction with surface temperature (Ts) from July 2002 to June 2015 and compute their radiative effects on Qr using the Fu-Liou-Gu plane-parallel radiation model. We find that the tropical mean (30°S-30°N) high cloud fraction decreases with increasing Ts at a rate of about -1.0 ± 0.34% K-1 from 2002 to 2015, which leads to an enhanced atmospheric cooling around 0.86 W m-2 K-1. On the other hand, the northern midlatitudes (30°N-60°N) high cloud fraction increases with surface warming at a rate of 1.85 ± 0.65% K-1 and the near-global mean (60°S-60°N) high cloud fraction shows a statistically insignificant decreasing trend with increasing Ts over the analysis period. Dividing high clouds into cirrus, cirrostratus, and deep convective clouds, we find that cirrus cloud fraction increases with surface warming at a rate of 0.32 ± 0.11% K-1 (0.01 ± 0.17% K-1) for the near-global mean (tropical mean), while cirrostratus and deep convective clouds decrease with surface warming at a rate of -0.02 ± 0.18% K-1 and -0.33 ± 0.18% K-1 for the near-global mean and -0.64 ± 0.23% K-1 and -0.37 ± 0.13% K-1 for the tropical mean, respectively. High cloud fraction response to feedback to Ts accounts for approximately 1.9 ± 0.7% and 16.0 ± 6.1% of the increase in precipitation per unit surface warming over the period of 2002-2015 for the near-global mean and the tropical mean, respectively.

  6. Evaluation of high-resolution satellite precipitation products with surface rain gauge observations from Laohahe Basin in northern China

    Directory of Open Access Journals (Sweden)

    Shan-hu Jiang

    2010-12-01

    Full Text Available Three high-resolution satellite precipitation products, the Tropical Rainfall Measuring Mission (TRMM standard precipitation products 3B42V6 and 3B42RT and the Climate Precipitation Center's (CPC morphing technique precipitation product (CMORPH, were evaluated against surface rain gauge observations from the Laohahe Basin in northern China. Widely used statistical validation indices and categorical statistics were adopted. The evaluations were performed at multiple time scales, ranging from daily to yearly, for the years from 2003 to 2008. The results show that all three satellite precipitation products perform very well in detecting the occurrence of precipitation events, but there are some different biases in the amount of precipitation. 3B42V6, which has a bias of 21%, fits best with the surface rain gauge observations at both daily and monthly scales, while the biases of 3B42RT and CMORPH, with values of 81% and 67%, respectively, are much higher than a normal receivable threshold. The quality of the satellite precipitation products also shows monthly and yearly variation: 3B42RT has a large positive bias in the cold season from September to April, while CMORPH has a large positive bias in the warm season from May to August, and they all attained their best values in 2006 (with 10%, 50%, and −5% biases for 3B42V6, 3B42RT, and CMORPH, respectively. Our evaluation shows that, for the Laohahe Basin, 3B42V6 has the best correspondence with the surface observations, and CMORPH performs much better than 3B42RT. The large errors of 3B42RT and CMORPH remind us of the need for new improvements to satellite precipitation retrieval algorithms or feasible bias adjusting methods.

  7. Chemistry and isotopic composition of precipitation and surface waters in Khumbu valley (Nepal Himalaya): N dynamics of high elevation basins

    Energy Technology Data Exchange (ETDEWEB)

    Balestrini, Raffaella, E-mail: balestrini@irsa.cnr.it [Water Research Institute, National Research Council (IRSA-CNR), Via del Mulino 19, Brugherio, MB (Italy); Polesello, Stefano [Water Research Institute, National Research Council (IRSA-CNR), Via del Mulino 19, Brugherio, MB (Italy); Sacchi, Elisa [Department of Earth and Environmental Sciences, University of Pavia and IGG-CNR, Via Ferrata 1, 27100 Pavia (Italy)

    2014-07-01

    We monitored the chemical and isotopic compositions of wet depositions, at the Pyramid International Laboratory (5050 m a.s.l.), and surrounding surface waters, in the Khumbu basin, to understand precipitation chemistry and to obtain insights regarding ecosystem responses to atmospheric inputs. The major cations in the precipitation were NH{sub 4}{sup +} and Ca{sup 2+}, whereas the main anion was HCO{sub 3}{sup −}, which constituted approximately 69% of the anions, followed by NO{sub 3}{sup −}, SO{sub 4}{sup 2−} and Cl{sup −}. Data analysis suggested that Na{sup +}, Cl{sup −} and K{sup +} were derived from the long-range transport of marine aerosols. Ca{sup 2+}, Mg{sup 2+} and HCO{sub 3}{sup −} were related to rock and soil dust contributions and the NO{sub 3}{sup −} and SO{sub 4}{sup 2−} concentrations were derived from anthropogenic sources. Furthermore, NH{sub 4}{sup +} was derived from gaseous NH{sub 3} scavenging. The isotopic composition of weekly precipitation ranged from − 1.9 to − 23.2‰ in δ{sup 18}O, and from − 0.8 to − 174‰ in δ{sup 2}H, with depleted values characterizing the central part of the monsoon period. The chemical composition of the stream water was dominated by calcite and/or gypsum dissolution. However, the isotopic composition of the stream water did not fully reflect the composition of the monsoon precipitation, which suggested that other water sources contributed to the stream flow. Precipitation contents for all ions were the lowest ones among those measured in high elevation sites around the world. During the monsoon periods the depositions were not substantially influenced by anthropogenic inputs, while in pre- and post-monsoon seasons the Himalayas could not represent an effective barrier for airborne pollution. In the late monsoon phase, the increase of ionic contents in precipitation could also be due to a change in the moisture source. The calculated atmospheric N load (0.30 kg ha{sup −1} y{sup −1

  8. The evolution of extreme precipitations in high resolution scenarios over France

    Science.gov (United States)

    Colin, J.; Déqué, M.; Somot, S.

    2009-09-01

    Over the past years, improving the modelling of extreme events and their variability at climatic time scales has become one of the challenging issue raised in the regional climate research field. This study shows the results of a high resolution (12 km) scenario run over France with the limited area model (LAM) ALADIN-Climat, regarding the representation of extreme precipitations. The runs were conducted in the framework of the ANR-SCAMPEI national project on high resolution scenarios over French mountains. As a first step, we attempt to quantify one of the uncertainties implied by the use of LAM : the size of the area on which the model is run. In particular, we address the issue of whether a relatively small domain allows the model to create its small scale process. Indeed, high resolution scenarios cannot be run on large domains because of the computation time. Therefore one needs to answer this preliminary question before producing and analyzing such scenarios. To do so, we worked in the framework of a « big brother » experiment. We performed a 23-year long global simulation in present-day climate (1979-2001) with the ARPEGE-Climat GCM, at a resolution of approximately 50 km over Europe (stretched grid). This first simulation, named ARP50, constitutes the « big brother » reference of our experiment. It has been validated in comparison with the CRU climatology. Then we filtered the short waves (up to 200 km) from ARP50 in order to obtain the equivalent of coarse resolution lateral boundary conditions (LBC). We have carried out three ALADIN-Climat simulations at a 50 km resolution with these LBC, using different configurations of the model : * FRA50, run over a small domain (2000 x 2000 km, centered over France), * EUR50, run over a larger domain (5000 x 5000 km, centered over France as well), * EUR50-SN, run over the large domain (using spectral nudging). Considering the facts that ARPEGE-Climat and ALADIN-Climat models share the same physics and dynamics

  9. Effect of carbide precipitates on high temperature creep of a 20Cr-25Ni austenitic stainless steel

    International Nuclear Information System (INIS)

    Yamane, T.; Takahashi, Y.; Nakagawa, K.

    1984-01-01

    The high temperature creep of an austenitic stainless steel having carbide precipitates, is different from that of the carbide precipitate-free one. Strain rates of the steady state creep d(epsilonsub(s))/dt, or minimum strain rates of the creep in precipitate hardened and dispersion strengthened alloys at the creep temperature T, can be expressed by Sherby-Dorn's equation d(epsilonsub(s))/dt = Aσsup(n) exp (-Qsub(c)/RT). The stress exponent n, and the activation energy for creep Qsub(c), in a power law creep region, are more than those of unstrengthened alloys, where σ is the creep stress, R the gas constant and A the constant. In this research, the influence of carbide precipitates on steady creep rates, is investigated. Experimental details are given. Results are given and discussed. (author)

  10. Discontinuous precipitation in a nickel-free high nitrogen austenitic stainless steel on solution nitriding

    Science.gov (United States)

    Mohammadzadeh, Roghayeh; Akbari, Alireza; Grumsen, Flemming B.; Somers, Marcel A. J.

    2017-10-01

    Chromium-rich nitride precipitates in production of nickel-free austenitic stainless steel plates via pressurised solution nitriding of Fe-22.7Cr-2.4Mo ferritic stainless steel at 1473 K (1200 °C) under a nitrogen gas atmosphere was investigated. The microstructure, chemical and phase composition, morphology and crystallographic orientation between the resulted austenite and precipitates were investigated using optical microscopy, X-ray Diffraction (XRD), Scanning and Transmission Electron Microscopy (TEM) and Electron Back Scatter Diffraction (EBSD). On prolonged nitriding, Chromium-rich nitride precipitates were formed firstly close to the surface and later throughout the sample with austenitic structure. Chromium-rich nitride precipitates with a rod or strip-like morphology was developed by a discontinuous cellular precipitation mechanism. STEM-EDS analysis demonstrated partitioning of metallic elements between austenite and nitrides, with chromium contents of about 80 wt.% in the precipitates. XRD analysis indicated that the Chromium-rich nitride precipitates are hexagonal (Cr, Mo)2N. Based on the TEM studies, (Cr, Mo)2N precipitates presented a (1 1 1)γ//(0 0 2)(Cr, Mo)2N, ?γ//?(Cr, Mo)2N orientation relationship with respect to the austenite matrix. EBSD studies revealed that the austenite in the regions that have transformed into austenite and (Cr, Mo)2N have no orientation relation to the untransformed austenite.

  11. The full annual carbon balance of a subtropical coniferous plantation is highly sensitive to autumn precipitation.

    Science.gov (United States)

    Xu, Mingjie; Wang, Huimin; Wen, Xuefa; Zhang, Tao; Di, Yuebao; Wang, Yidong; Wang, Jianlei; Cheng, Chuanpeng; Zhang, Wenjiang

    2017-08-30

    Deep understanding of the effects of precipitation on carbon budgets is essential to assess the carbon balance accurately and can help predict potential variation within the global change context. Therefore, we addressed this issue by analyzing twelve years (2003-2014) of observations of carbon fluxes and their corresponding temperature and precipitation data in a subtropical coniferous plantation at the Qianyanzhou (QYZ) site, southern China. During the observation years, this coniferous ecosystem experienced four cold springs whose effects on the carbon budgets were relatively clear based on previous studies. To unravel the effects of temperature and precipitation, the effects of autumn precipitation were examined by grouping the data into two pools based on whether the years experienced cold springs. The results indicated that precipitation in autumn can accelerate the gross primary productivity (GPP) of the following year. Meanwhile, divergent effects of precipitation on ecosystem respiration (Re) were found. Autumn precipitation was found to enhance Re in normal years but the same regulation was not found in the cold-spring years. These results suggested that for long-term predictions of carbon balance in global climate change projections, the effects of precipitation must be considered to better constrain the uncertainties associated with the estimation.

  12. Discontinuous precipitation in a nickel-free high nitrogen austenitic stainless steel on solution nitriding

    DEFF Research Database (Denmark)

    Mohammadzadeh, Roghayeh; Akbari, Alireza; Grumsen, Flemming Bjerg

    2017-01-01

    Chromium-rich nitride precipitates in production of nickel-free austenitic stainless steel plates via pressurised solution nitriding of Fe–22.7Cr–2.4Mo ferritic stainless steel at 1473 K (1200 °C) under a nitrogen gas atmosphere was investigated. The microstructure, chemical and phase composition......, morphology and crystallographic orientation between the resulted austenite and precipitates were investigated using optical microscopy, X-ray Diffraction (XRD), Scanning and Transmission Electron Microscopy (TEM) and Electron Back Scatter Diffraction (EBSD). On prolonged nitriding, Chromium-rich nitride...... precipitates were formed firstly close to the surface and later throughout the sample with austenitic structure. Chromium-rich nitride precipitates with a rod or strip-like morphology was developed by a discontinuous cellular precipitation mechanism. STEM-EDS analysis demonstrated partitioning of metallic...

  13. Radioresistance increase in polymers at high pressures

    International Nuclear Information System (INIS)

    Milinchuk, V.; Kirjukhin, V.; Klinshpont, E.

    1977-01-01

    The effect was studied of very high pressures ranging within 100 and 2,700 MPa on the radioresistance of polytetrafluoroethylene, polypropylene and polyethylene in gamma irradiation. For experiments industrial polymers in the shape of blocks, films and fibres were used. It is shown that in easily breakable polymers, such as polytetrafluoroethylene and polypropylene 1.3 to 2 times less free radicals are formed as a result of gamma irradiation and a pressure of 150 MPa than at normal pressure. The considerably reduced radiation-chemical formation of radicals and the destruction suppression by cross-linking in polymers is the evidence of the polymer radioresistance in irradiation at high pressures. (J.B.)

  14. High efficiency and low cost preparation of size controlled starch nanoparticles through ultrasonic treatment and precipitation.

    Science.gov (United States)

    Chang, Yanjiao; Yan, Xiaoxia; Wang, Qian; Ren, Lili; Tong, Jin; Zhou, Jiang

    2017-07-15

    The purpose of this work was to develop an approach to produce size controlled starch nanoparticles (SNPs), via precipitation with high efficiency and low cost. High concentration starch aqueous pastes (up to 5wt.%) were treated by ultrasound. Viscosity measurements and size exclusion chromatography characterization revealed that, after 30min ultrasonic treatment, viscosity of the starch pastes decreased two orders of magnitude and the weight average molecular weight of the starch decreased from 8.4×10 7 to 2.7×10 6 g/mol. Dynamic light scattering measurements and scanning electron microscopy observations showed that the SNPs prepared from the starch pastes with ultrasonic treatments were smaller (∼75nm) and more uniform. Moreover, SNPs could be obtained using less non-solvents. X-ray diffraction results indicated that effect of the ultrasonic treatment on crystalline structure of the SNPs was negligible. Ultrasound can be utilized to prepare smaller SNPs through nanoprecipitation with higher efficiency and lower cost. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Electrochemical probing of high-level radioactive waste tanks containing washed sludge and precipitates

    International Nuclear Information System (INIS)

    Bickford, D.F.; Congdon, J.W.; Oblath, S.B.

    1986-12-01

    At the US Department of Energy's Savannah River Plant, corrosion of carbon steel storage tanks containing alkaline, high-level radioactive waste is controlled by specification of limits on waste composition and temperature. Processes for the preparation of waste for final disposal will result in waste with low corrosion inhibitor concentrations and, in some cases, high aromatic organic concentrations, neither of which are characteristic of previous operations. Laboratory tests, conducted to determine minimum corrosion inhibitor levels indicated pitting of carbon steel near the waterline for proposed storage conditions. In situ electrochemical measurements of full-scale radioactive process demonstrations have been conducted to assess the validity of laboratory tests. Probes included pH, Eh (potential relative to a standard hydrogen electrode), tank potential, and alloy coupons. In situ results are compared to those of the laboratory tests, with particular regard given to simulated solution composition. Transition metal hydroxide sludge contains strong passivating species for carbon steel. Washed precipitate contains organic species that lower solution pH and tend to reduce passivating films, requiring higher inhibitor concentrations than the 0.01 molar nitrite required for reactor fuel reprocessing wastes. Periodic agitation, to keep the organic phase suspended, or cathodic protection are possible alternatives to higher nitrite inhibitor concentrations

  16. High resolution forecast of heavy precipitation with Lokal Modell: analysis of two case studies in the Alpine area

    Directory of Open Access Journals (Sweden)

    M. Elementi

    2005-01-01

    Full Text Available Northern Italy is frequently affected by severe precipitation conditions often inducing flood events with associated loss of properties, damages and casualties. The capability of correctly forecast these events, strongly required for an efficient support to civil protection actions, is still nowadays a challenge. This difficulty is also related with the complex structure of the precipitation field in the Alpine area and, more generally, over the Italian territory. Recently a new generation of non-hydrostatic meteorological models, suitable to be used at very high spatial resolution, has been developed. In this paper the performance of the non-hydrostatic Lokal Modell developed by the COSMO Consortium, is analysed with regard to a couple of intense precipitation events occurred in the Piemonte region in Northern Italy. These events were selected among the reference cases of the Hydroptimet/INTERREG IIIB project. LM run at the operational resolution of 7km provides a good forecast of the general rain structure, with an unsatisfactory representation of the precipitation distribution across the mountain ranges. It is shown that the inclusion of the new prognostic equations for cloud ice, rain and snow produces a remarkable improvement, reducing the precipitation in the upwind side and extending the intense rainfall area to the downwind side. The unrealistic maxima are decreased towards observed values. The use of very high horizontal resolution (2.8 km improves the general shape of the precipitation field in the flat area of the Piemonte region but, keeping active the moist convection scheme, sparse and more intense rainfall peaks are produced. When convective precipitation is not parametrised but explicitly represented by the model, this negative effect is removed.

  17. Intensive precipitation observation greatly improves hydrological modelling of the poorly gauged high mountain Mabengnong catchment in the Tibetan Plateau

    Science.gov (United States)

    Wang, Li; Zhang, Fan; Zhang, Hongbo; Scott, Christopher A.; Zeng, Chen; Shi, Xiaonan

    2018-01-01

    Precipitation is one of the most critical inputs for models used to improve understanding of hydrological processes. In high mountain areas, it is challenging to generate a reliable precipitation data set capturing the spatial and temporal heterogeneity due to the harsh climate, extreme terrain and the lack of observations. This study conducts intensive observation of precipitation in the Mabengnong catchment in the southeast of the Tibetan Plateau during July to August 2013. Because precipitation is greatly influenced by altitude, the observed data are used to characterize the precipitation gradient (PG) and hourly distribution (HD), showing that the average PG is 0.10, 0.28 and 0.26 mm/d/100 m and the average duration is around 0.1, 0.8 and 5.2 h for trace, light and moderate rain, respectively. A distributed biosphere hydrological model based on water and energy budgets with improved physical process for snow (WEB-DHM-S) is applied to simulate the hydrological processes with gridded precipitation data derived from a lower altitude meteorological station and the PG and HD characterized for the study area. The observed runoff, MODIS/Terra snow cover area (SCA) data, and MODIS/Terra land surface temperature (LST) data are used for model calibration and validation. Runoff, SCA and LST simulations all show reasonable results. Sensitivity analyses illustrate that runoff is largely underestimated without considering PG, indicating that short-term intensive precipitation observation has the potential to greatly improve hydrological modelling of poorly gauged high mountain catchments.

  18. Covariability of seasonal temperature and precipitation over the Iberian Peninsula in high-resolution regional climate simulations (1001-2099)

    Science.gov (United States)

    Fernández-Montes, S.; Gómez-Navarro, J. J.; Rodrigo, F. S.; García-Valero, J. A.; Montávez, J. P.

    2017-04-01

    Precipitation and surface temperature are interdependent variables, both as a response to atmospheric dynamics and due to intrinsic thermodynamic relationships and feedbacks between them. This study analyzes the covariability of seasonal temperature (T) and precipitation (P) across the Iberian Peninsula (IP) using regional climate paleosimulations for the period 1001-1990, driven by reconstructions of external forcings. Future climate (1990-2099) was simulated according to SRES scenarios A2 and B2. These simulations enable exploring, at high spatial resolution, robust and physically consistent relationships. In winter, positive P-T correlations dominate west-central IP (Pearson correlation coefficient ρ = + 0.43, for 1001-1990), due to prevalent cold-dry and warm-wet conditions, while this relationship weakens and become negative towards mountainous, northern and eastern regions. In autumn, negative correlations appear in similar regions as in winter, whereas for summer they extend also to the N/NW of the IP. In spring, the whole IP depicts significant negative correlations, strongest for eastern regions (ρ = - 0.51). This is due to prevalent frequency of warm-dry and cold-wet modes in these regions and seasons. At the temporal scale, regional correlation series between seasonal anomalies of temperature and precipitation (assessed in 31 years running windows in 1001-1990) show very large multidecadal variability. For winter and spring, periodicities of about 50-60 years arise. The frequency of warm-dry and cold-wet modes appears correlated with the North Atlantic Oscillation (NAO), explaining mainly co-variability changes in spring. For winter and some regions in autumn, maximum and minimum P-T correlations appear in periods with enhanced meridional or easterly circulation (low or high pressure anomalies in the Mediterranean and Europe). In spring and summer, the Atlantic Multidecadal Oscillation shows some fingerprint on the frequency of warm/cold modes. For

  19. Carbon and oxygen stable isotopes in large herbivore tooth enamel illustrate a mid-Miocene precipitation increase in the interior Pacific Northwest

    Science.gov (United States)

    Drewicz, A.; Kohn, M. J.

    2017-12-01

    The mid-Miocene Climatic Optimum (MMCO; 13.75-16.9 Ma), represents the warmest period in Earth's history during the last 35 Ma, and is distinguished by low ice volume and high ocean water temperatures. The MMCO has been associated with high atmospheric CO2 (pCO2) similar to levels anticipated in the next century. Thus, understanding MMCO climate may help enlighten predictions of future climate change. Here, using new stable oxygen and carbon isotopes of fossil ungulate tooth enamel from before, during, and after the MMCO, we show that high pCO2 corresponds with warm-wet conditions, whereas low pCO2 corresponds with cool-dry conditions. We specifically show that mean annual precipitation (MAP), as inferred from tooth enamel δ13C values and corrected for atmospheric δ13C values (Δ13C), increased with increasing pCO2. Values of Δ13C > 19.5 ‰ in the lower John Day ( 27 Ma) and Mascall ( 15.3 Ma) localities imply relatively high mean annual precipitation (MAP = 550-850 mm/yr). Values of Δ 13C < 18.5 ‰ at 18 Ma and at four levels between 15 and 3 Ma imply low MAP (≤250 mm/yr), similar to modern climate. High MAP values generally correlate with high pCO2 levels, as inferred from marine records, implicating pCO2 as a principal driver of MAP in the Pacific Northwest. A climate oscillation model best explains our δ 13C data, such that warm-wet conditions during high pCO2 events alternated with cool-dry conditions during low pCO2 events on timescales of 100 kyr. The MMCO may have been more dynamic than originally considered, with wet-warm and cool-dry cycles reflecting Milankovitch cycles. High δ18O values in specimens from the John Day (21.8±0.6 ‰ V-SMOW) and Mascall (21.3±0.5 ‰) Formations may reflect lower elevations for the upwind Cascade Range prior to 7 Ma, or its proximity to the coast compared to more inland sites (δ18O = 17.7±0.9 to 19.6±1.1 ‰). Unusually high δ18O values of Dromomeryx sp. from Red Basin (27.4±0.6 ‰) most likely reflect

  20. On the importance of appropriate precipitation gauge catch correction for hydrological modelling at mid to high latitudes

    Science.gov (United States)

    Stisen, S.; Højberg, A. L.; Troldborg, L.; Refsgaard, J. C.; Christensen, B. S. B.; Olsen, M.; Henriksen, H. J.

    2012-11-01

    precipitation correction should be carried out for studies requiring a sound dynamic description of hydrological processes, and it is of particular importance when using hydrological models to make predictions for future climates when the snow/rain composition will differ from the past climate. This conclusion is expected to be applicable for mid to high latitudes, especially in coastal climates where winter precipitation types (solid/liquid) fluctuate significantly, causing climatological mean correction factors to be inadequate.

  1. On the importance of appropriate precipitation gauge catch correction for hydrological modelling at mid to high latitudes

    Directory of Open Access Journals (Sweden)

    S. Stisen

    2012-11-01

    . We conclude that TSV precipitation correction should be carried out for studies requiring a sound dynamic description of hydrological processes, and it is of particular importance when using hydrological models to make predictions for future climates when the snow/rain composition will differ from the past climate. This conclusion is expected to be applicable for mid to high latitudes, especially in coastal climates where winter precipitation types (solid/liquid fluctuate significantly, causing climatological mean correction factors to be inadequate.

  2. Evaluation of high resolution spatio-temporal precipitation extremes from a stochastic weather generator

    DEFF Research Database (Denmark)

    Sørup, Hjalte Jomo Danielsen; Christensen, O. B.; Arnbjerg-Nielsen, Karsten

    2017-01-01

    Spatio-temporal rainfall is modelled for the North-Eastern part of Zealand (Denmark) using the Spatio-Temporal Neyman-Scott Rectangular Pulses model as implemented in the RainSim software. Hourly precipitation series for fitting the model are obtained from a dense network of tipping bucket rain...... gauges in the model area. The spatiotemporal performance of the model with respect to precipitation extremes is evaluated in the points of a 2x2 km regular grid covering the full model area. The model satisfactorily reproduces the extreme behaviour of the observed precipitation with respect to event...... intensity levels and unconditional spatial correlation when evaluated using an event based ranking approach at point scale and an advanced spatiotemporal coupling of extreme events. Prospectively the model can be used as a tool to evaluate the impact of climate change without relying on precipitation output...

  3. Obtaining Highly Crystalline Barium Sulphate Nanoparticles via Chemical Precipitation and Quenching in Absence of Polymer Stabilizers

    Directory of Open Access Journals (Sweden)

    Ángela B. Sifontes

    2015-01-01

    Full Text Available Here we report the synthesis of barium sulphate (BaSO4 nanoparticles from Ba(OH2/BaCl2 solutions by a combined method of precipitation and quenching in absence of polymer stabilizers. Transmission electron microscopy (HRTEM, Fourier transforms infrared spectroscopy (FTIR, and X-ray diffraction (XRD were employed to characterize the particles. The Scherrer formula was applied to estimate the particle size using the width of the diffraction peaks. The obtained results indicate that the synthesized material is mainly composed of nanocrystalline barite, with nearly spherical morphology, and diameters ranging from 4 to 92 nm. The lattice images of nanoparticles were clearly observed by HRTEM, indicating a high degree of crystallinity and phase purity. In addition, agglomerates with diameters between 20 and 300 nm were observed in both lattice images and dynamic light scattering measurements. The latter allowed obtaining the particle size distribution, the evolution of the aggregate size in time of BaSO4 in aqueous solutions, and the sedimentation rate of these solutions from turbidimetry measurements. A short discussion on the possible medical applications is presented.

  4. Group precipitation and age hardening of nanostructured Fe-based alloys with ultra-high strengths

    Science.gov (United States)

    Jiao, Z. B.; Luan, J. H.; Miller, M. K.; Yu, C. Y.; Liu, C. T.

    2016-01-01

    The precipitation of nanoparticles plays a key role in determining the properties of many structural materials, and the understanding of their formation and stabilization mechanisms has been a long standing interest in the material field. However, the critical issues involving the group precipitation of various nanoparticles and their cooperative hardening mechanism remain elusive in the newly discovered Fe-based alloys with nanostructures. Here we quantitatively elucidate the nucleation mechanism, evolution kinetics and hardening effects of the group-precipitated nanoparticles in the Fe-Cu-Ni-Al-based alloys by atom probe tomography together with both first-principles and thermodynamic calculations. Our results provide the compelling evidence for two interesting but complex group precipitation pathways of nanoparticles, i.e., the Cu-rich and NiAl-based precipitations. The co-existence of the two precipitation pathways plays a key role in age hardening kinetics and ultimately enhances the hardening response, as compared to the single particle type of strengthening, therefore providing an effective new approach for strengthening materials for structural applications. PMID:26892834

  5. Correction of Excessive Precipitation Over Steep and High Mountains in a General Circulation Model

    Science.gov (United States)

    Chao, Winston C.

    2012-01-01

    Excessive precipitation over steep and high mountains (EPSM) is a well-known problem in GCMs and meso-scale models. This problem impairs simulation and data assimilation products. Among the possible causes investigated in this study, we found that the most important one, by far, is a missing upward transport of heat out of the boundary layer due to the vertical circulations forced by the daytime upslope winds, which are forced by the heated boundary layer on subgrid-scale slopes. These upslope winds are associated with large subgrid-scale topographic variation, which is found over steep and high mountains. Without such subgridscale heat ventilation, the resolvable-scale upslope flow in the boundary layer generated by surface sensible heat flux along the mountain slopes is excessive. Such an excessive resolvablescale upslope flow combined with the high moisture content in the boundary layer results in excessive moisture transport toward mountaintops, which in turn gives rise to EPSM. Other possible causes of EPSM that we have investigated include 1) a poorly-designed horizontal moisture flux in the terrain-following coordinates, 2) the condition for cumulus convection being too easily satisfied at mountaintops, 3) the presence of conditional instability of the computational kind, and 4) the absence of blocked flow drag. These are all minor or inconsequential. We have parameterized the ventilation effects of the subgrid-scale heated-slope-induced vertical circulation (SHVC) by removing heat from the boundary layer and depositing it in layers higher up when the topographic variance exceeds a critical value. Test results using NASA/Goddard's GEOS-S GCM have shown that this largely solved the EPSM problem.

  6. Vertical structure and microphysical characteristics of precipitation on the high terrain and lee side of the Olympic Mountains

    Science.gov (United States)

    Zagrodnik, J. P.; McMurdie, L. A.; Houze, R.

    2017-12-01

    As mid-latitude cyclones pass over coastal mountain ranges, the processes producing their clouds and precipitation are modified when they encounter complex terrain, leading to a maximum in precipitation fallout on the windward slopes and a minimum on the lee side. The precipitation that does reach the high terrain and lee side of a mountain range can be theoretically determined by a complex interaction between the dynamics of air lifting over the terrain, the thermodynamics of moist air, and the microphysical time required to grow particles large enough to fall out. To date, there have been few observational studies that have focused on the nonlinear microphysical processes contributing to the variability of precipitation that is received on the lee side slopes of a mountain range such as the Olympic Mountains. The 2015-16 Olympic Mountains Experiment (OLYMPEX) collected unprecedented observations on the high terrain and lee side of the Olympic Mountains including frequent soundings on Vancouver Island, dual-polarization Doppler radar, multi-frequency airborne radar, and ground-based particle size and crystal habit observations at the higher elevation Hurricane Ridge site. We utilize these observations to examine the evolution of the vertical structure and microphysical precipitation characteristics over the high terrain and leeside within the context of large-scale dynamic and thermodynamic conditions that evolve during the passage of cold season mid-latitude cyclones. The primary goal is to determine the degree to which the observed variability in lee side precipitation amount and microphysical properties are controlled by variations in temperature, flow speed and direction, shear, and stability associated with characteristic synoptic storm sectors and frontal passages.

  7. Three-phase current transformer rectifier sets. High-voltage power supplies for difficult conditions in electrostatic precipitators

    Energy Technology Data Exchange (ETDEWEB)

    Stackelberg, Josef von [Rico-Werk Eiserlo und Emmrich GmbH, Toenisvorst (Germany)

    2013-04-01

    The precipitation rate of electrostatic precipitators (ESP) highly depends on the consistency of waste gas. Among other things, electrical conductivity plays an important role as well as the ability of particles to be electrically charged or ionised. Within certain limits, common ESPs are able to clean waste gas satisfactorily. If the dust attributes exceed these limits, more sophisticated technical solutions are required in the ESP to meet the demands for the gas cleaning equipment. In these cases, a three phase transformer rectifier system offers an alternative to the conventional single phase system, as it delivers a smooth direct current voltage over a wide voltage range. (orig.)

  8. Preplastic strain effect on chromium carbides precipitation of type 316 stainless steel during high-temperature ageing

    International Nuclear Information System (INIS)

    Mao, X.; Zhao, W.

    1992-01-01

    Long exposure of Type 316 stainless steel to elevated temperature (400-900 o C) is known to cause high-temperature embrittlement due to chromium carbides and σ-phase precipitating in grain boundaries. Numerous investigations have been published on the mechanical properties and microstructure changes occurring during such exposure. However, no investigations exist on the preplastic deformation effect on chromium carbide precipitation in the grain matrix and grain boundary during high-temperature ageing of Type 316 stainless steel and then its effects on the room-temperature tensile properties. Since the stainless steel sometimes is deformed before use at high temperatures, it is necessary to study the preplastic strain effect of the stainless steel on the microstructure change and mechanical property change during high-temperature exposure. The purpose of the present investigation was to carry out such a study. The conclusions reached are as follows. First, chromium carbides are precipitated in deformation lines (slip lines) and then the amount of chromium carbides precipitation in the grain boundary is relatively reduced in predeformed stainless steel after ageing. Secondly, plastic strain pretreatments of and subsequent ageing treatments of Type 316 stainless steel can improve its tensile ductility. Finally, secondary cracking of aged stainless steel occurs in a normal tensile test. The secondary cracking can be reduced by adding preplastic strain into the material. (Author)

  9. A European daily high-resolution gridded dataset of surface temperature and precipitation for 1950-2006

    NARCIS (Netherlands)

    Haylock, M.; Hofstra, N.; Klein Tank, A.; Klok, L.; Jones, P.; New, M.

    2008-01-01

    We present a European land-only daily high-resolution gridded data set for precipitation and minimum, maximum, and mean surface temperature for the period 1950–2006. This data set improves on previous products in its spatial resolution and extent, time period, number of contributing stations, and

  10. Increased precipitation accelerates soil organic matter turnover associated with microbial community composition in topsoil of alpine grassland on the eastern Tibetan Plateau.

    Science.gov (United States)

    Han, Conghai; Wang, Zongli; Si, Guicai; Lei, Tianzhu; Yuan, Yanli; Zhang, Gengxin

    2017-10-01

    Large quantities of carbon are stored in alpine grassland of the Tibetan Plateau, which is extremely sensitive to climate change. However, it remains unclear whether soil organic matter (SOM) in different layers responds to climate change analogously, and whether microbial communities play vital roles in SOM turnover of topsoil. In this study we measured and collected SOM turnover by the 14 C method in alpine grassland to test climatic effects on SOM turnover in soil profiles. Edaphic properties and microbial communities in the northwestern Qinghai Lake were investigated to explore microbial influence on SOM turnover. SOM turnover in surface soil (0-10 cm) was more sensitive to precipitation than that in subsurface layers (10-40 cm). Precipitation also imposed stronger effects on the composition of microbial communities in the surface layer than that in deeper soil. At the 5-10 cm depth, the SOM turnover rate was positively associated with the bacteria/fungi biomass ratio and the relative abundance of Acidobacteria, both of which are related to precipitation. Partial correlation analysis suggested that increased precipitation could accelerate the SOM turnover rate in topsoil by structuring soil microbial communities. Conversely, carbon stored in deep soil would be barely affected by climate change. Our results provide valuable insights into the dynamics and storage of SOM in alpine grasslands under future climate scenarios.

  11. Estimating and forecasting the precipitable water vapor from GOES satellite data at high altitude sites

    Science.gov (United States)

    Marín, Julio C.; Pozo, Diana; Curé, Michel

    2015-01-01

    In this work, we describe a method to estimate the precipitable water vapor (PWV) from Geostationary Observational Environmental Satellite (GOES) data at high altitude sites. The method was applied at Atacama Pathfinder Experiment (APEX) and Cerro Toco sites, located above 5000 m altitude in the Chajnantor plateau, in the north of Chile. It was validated using GOES-12 satellite data over the range 0-1.2 mm since submillimeter/millimeter astronomical observations are only useful within this PWV range. The PWV estimated from GOES and the Final Analyses (FNL) at APEX for 2007 and 2009 show root mean square error values of 0.23 mm and 0.36 mm over the ranges 0-0.4 mm and 0.4-1.2 mm, respectively. However, absolute relative errors of 51% and 33% were shown over these PWV ranges, respectively. We recommend using high-resolution thermodynamic profiles from the Global Forecast System (GFS) model to estimate the PWV from GOES data since they are available every three hours and at an earlier time than the FNL data. The estimated PWV from GOES/GFS agrees better with the observed PWV at both sites during night time. The largest errors are shown during daytime. Short-term PWV forecasts were implemented at both sites, applying a simple persistence method to the PWV estimated from GOES/GFS. The 12 h and 24 h PWV forecasts evaluated from August to October 2009 indicates that 25% of them show a very good agreement with observations whereas 50% of them show reasonably good agreement with observations. Transmission uncertainties calculated for PWV estimations and forecasts over the studied sites are larger over the range 0-0.4 mm than over the range 0.4-1.2 mm. Thus, the method can be used over the latter interval with more confidence.

  12. Enhancement of metal-nanoparticle precipitation by co-irradiation of high-energy heavy ions and laser in silica glass

    International Nuclear Information System (INIS)

    Okubo, N.; Umeda, N.; Takeda, Y.; Kishimoto, N.

    2003-01-01

    Simultaneous laser irradiation under ion irradiation is conducted to control nanoparticle precipitation in amorphous (a-)SiO 2 . Copper ions of 3 MeV and photons of 532 nm by Nd:YAG laser are irradiated to substrates of a-SiO 2 . The ion dose rate and total dose are set at 2-10 μA/cm 2 and 3.0 x 10 16 -3.0 x 10 17 ions/cm 2 , respectively, and the laser power density is 0.05-0.2 J/cm 2 pulse at 10 Hz. The laser is simultaneously irradiated with ions in the co-irradiation mode, and the result is compared to that in the sequential and ion-only irradiation. Cross-sectional TEM of the irradiated specimens is conducted after measuring optical absorption spectra. In the case of co-irradiation of intense laser power and high dose (0.2 J/cm 2 pulse and 3.0 x 10 17 ions/cm 2 ), Cu nanoparticles precipitate much more extensively than in the sequential irradiation, increasing both the particle diameter and the total Cu atoms in the nanoparticles. The optical absorption spectra show a surface plasmon peak of the nanoparticles. The precipitation enhancement in the co-irradiation mode suggests that the electronic energy is absorbed by the dynamic electronic states and promotes the Cu precipitation via enhancing the atomic migration

  13. TEM Study of High-Temperature Precipitation of Delta Phase in Inconel 718 Alloy

    Directory of Open Access Journals (Sweden)

    Moukrane Dehmas

    2011-01-01

    Full Text Available Inconel 718 is widely used because of its ability to retain strength at up to 650∘C for long periods of time through coherent metastable  Ni3Nb precipitation associated with a smaller volume fraction of  Ni3Al precipitates. At very long ageing times at service temperature,  decomposes to the stable Ni3Nb phase. This latter phase is also present above the  solvus and is used for grain control during forging of alloy 718. While most works available on precipitation have been performed at temperatures below the  solvus, it appeared of interest to also investigate the case where phase precipitates directly from the fcc matrix free of  precipitates. This was studied by X-ray diffraction and transmission electron microscopy (TEM. TEM observations confirmed the presence of rotation-ordered domains in plates, and some unexpected contrast could be explained by double diffraction due to overlapping phases.

  14. Deformation induced dynamic recrystallization and precipitation strengthening in an Mg−Zn−Mn alloy processed by high strain rate rolling

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Jimiao; Song, Min [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Yan, Hongge [School of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Yang, Chao [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Ni, Song, E-mail: song.ni@csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China)

    2016-11-15

    The microstructure of a high strain-rate rolled Mg−Zn−Mn alloy was investigated by transmission electron microscopy to understand the relationship between the microstructure and mechanical properties. The results indicate that: (1) a bimodal microstructure consisting of the fine dynamic recrystallized grains and the largely deformed grains was formed; (2) a large number of dynamic precipitates including plate-like MgZn{sub 2} phase, spherical MgZn{sub 2} phase and spherical Mn particles distribute uniformly in the grains; (3) the major facets of many plate-like MgZn{sub 2} precipitates deviated several to tens of degrees (3°–30°) from the matrix basal plane. It has been shown that the high strength of the alloy is attributed to the formation of the bimodal microstructure, dynamic precipitation, and the interaction between the dislocations and the dynamic precipitates. - Highlights: •A bimodal microstructure was formed in a high strain-rate rolled Mg−Zn−Mn alloy. •Plate-like MgZn{sub 2}, spherical MgZn{sub 2} and spherical Mn phases were observed. •The major facet of the plate-like MgZn{sub 2} deviated from the matrix basal plane.

  15. Increase in socio-economic value of the fresh water fishery by reductions in the sulfur precipitation. [Norway]. Oekt samfunnsoekonomisk verdi av ferskvannsfisket ved reduksjoner i svovelnedfallet

    Energy Technology Data Exchange (ETDEWEB)

    Navrud, S

    1985-01-29

    A reduction of about 30% in the sulfur out-lets in Europe would lead to approximately the same reduction in acid precipitation in the South of Norway. The resulting improvement of water quality would facilitate improvements in the fish population. The report discussed various methods of measuring the socio-economic value of an assumed marginal increase of the amount of fresh water fish and recommends a ''parcel of methods'' in order to solve the estimation problem. A reduction of 30% in the acid precipitation would result in a total yearly socio-economic value increase of approximately 37 millions Norwegian kroners measured by the total willingness of payment by the Norwegian population - wich probably is an underestimation. 66 references, 22 drawings, 5 tables.

  16. A Central European precipitation climatology – Part II: Application of the high-resolution HYRAS data for COSMO-CLM evaluation

    Directory of Open Access Journals (Sweden)

    Susanne Brienen

    2016-05-01

    Full Text Available The horizontal resolution of regional climate model (RCM simulations is increasing constantly in the last years. For the evaluation of these simulations and the further development of the models, adequate observational data sets are required, in particular with respect to the spatial scales. The aim of this paper is to investigate the value of a new high-resolution precipitation climatology, the HYRAS-PRE v.2.0 data set, for the evaluation of RCM output. HYRAS-PRE is available for the time period 1951–2006 at daily resolution and covers ten river catchments in Germany and neighbouring countries at a spatial grid spacing of 5 km. A set of simulations with the regional climate model COSMO-CLM with three different grid spacings (~7$\\sim7$, 14 and 28 km is used for this model evaluation study. In addition, three other data sets with different horizontal resolution are considered in the comparisons: the E‑OBS v.8.0 gridded observations (~25$\\sim25$ km grid spacing, the ERA-Interim reanalysis (~79$\\sim79$ km and the analysis of the driving model GME (~40$\\sim40$–60 km. For three selected years, different spatial and temporal characteristics of daily precipitation are investigated. In all the analyzed precipitation characteristics, it is found that the variability between the data sets is very large. The benefit of an evaluation with HYRAS-PRE compared to coarser-resolved observations becomes visible especially in the representation of the frequency of occurrence distribution of daily precipitation amounts and in the spatial variability of different precipitation indices. A second goal of this study was to estimate the error when comparing a high resolution simulated precipitation field with coarser resolved observations. Comparing the HYRAS-PRE average over an area of 5×5$5\\times5$ grid points with the original HYRAS-PRE data results in a systematic underestimation of high values of all indices considered and an overestimation

  17. Precipitation of Second Phases in High-Interstitial-Alloyed Austenitic Steel

    Science.gov (United States)

    Lee, Tae-Ho; Ha, Heon-Young; Kim, Sung-Joon

    2011-12-01

    The precipitation reaction of an austenitic stainless steel containing N + C was investigated using transmission electron microscopy. The main precipitate formed during isothermal aging at 1123 K (850 °C) was M23C6 carbide, and its morphology gradually changed in a sequence of intergranular (along grain boundary) → cellular (or discontinuous) → intragranular (within grain interior) form with aging time. Irrespective of different morphologies, the M23C6 was consistently related to austenite matrix in accordance with the cube-on-cube orientation relationship. Based on the analysis of electron diffraction, two variants of intragranular M23C6 were identified, and they were related to each other by twin relation. Prolonged aging produced other types of precipitates—the rod-shaped Cr2N and the coarse irregular intermetallic sigma phase. The similarities and differences in precipitation behavior between N only and N + C alloyed austenitic stainless steels are briefly discussed.

  18. Evaluation of high resolution spatio-temporal precipitation extremes from a stochastic weather generator

    DEFF Research Database (Denmark)

    Sørup, Hjalte Jomo Danielsen; Christensen, O. B.; Arnbjerg-Nielsen, Karsten

    gauges in the model area. The spatio-temporal performance of the model with respect to precipitation extremes is evaluated in the points of a 2x2 km regular grid covering the full model area. The model satisfactorily reproduces the extreme behaviour of the observed precipitation with respect to event...... intensity levels and unconditional spatial correlation when evaluated using an event based ranking approach at point scale and an advanced spatio-temporal coupling of extreme events. Prospectively the model can be used as a tool to evaluate the impact of climate change without relying onprecipitation output......Spatio-temporal rainfall is modelled for the North-Eastern part of Zealand (Denmark) using the Spatio-Temporal Neyman-Scott Rectangular Pulses model as implemented in the RainSim software. Hourly precipitation series for fitting the model are obtained from a dense network of tipping bucket rain...

  19. Uncertainty of global summer precipitation in the CMIP5 models: a comparison between high-resolution and low-resolution models

    Science.gov (United States)

    Huang, Danqing; Yan, Peiwen; Zhu, Jian; Zhang, Yaocun; Kuang, Xueyuan; Cheng, Jing

    2018-04-01

    The uncertainty of global summer precipitation simulated by the 23 CMIP5 CGCMs and the possible impacts of model resolutions are investigated in this study. Large uncertainties exist over the tropical and subtropical regions, which can be mainly attributed to convective precipitation simulation. High-resolution models (HRMs) and low-resolution models (LRMs) are further investigated to demonstrate their different contributions to the uncertainties of the ensemble mean. It shows that the high-resolution model ensemble means (HMME) and low-resolution model ensemble mean (LMME) mitigate the biases between the MME and observation over most continents and oceans, respectively. The HMME simulates more precipitation than the LMME over most oceans, but less precipitation over some continents. The dominant precipitation category in the HRMs (LRMs) is the heavy precipitation (moderate precipitation) over the tropic regions. The combinations of convective and stratiform precipitation are also quite different: the HMME has much higher ratio of stratiform precipitation while the LMME has more convective precipitation. Finally, differences in precipitation between the HMME and LMME can be traced to their differences in the SST simulations via the local and remote air-sea interaction.

  20. Synthesis of highly sinterable YAG nanopowders by a modified co-precipitation method

    International Nuclear Information System (INIS)

    Chen, Zhi-Hui; Yang, Yun; Hu, Zhang-Gui; Li, Jiang-Tao; He, Shu-Li

    2007-01-01

    A hydrate precursor of yttrium aluminum garnet (YAG) was synthesized by a modified co-precipitation method, in which n-butanol was employed as a low-cost recyclable dehydration solvent. A mixed solution of ethanol and ammonia were used as precipitant. Pure YAG phase appeared after the as-prepared precursors being calcined at 850 o C for 2 h. The nanocrystalline YAG particles calcined at 1100 o C were well dispersed with average diameter of about 40 nm, which can be densified to transparency under vacuum sintering at 1700 o C for 5 h with TEOS as sintering additive

  1. Layer-by-layer modification of high surface curvature nanoparticles with weak polyelectrolytes using a multiphase solvent precipitation process.

    Science.gov (United States)

    Nagaraja, Ashvin T; You, Yil-Hwan; Choi, Jeong-Wan; Hwang, Jin-Ha; Meissner, Kenith E; McShane, Michael J

    2016-03-15

    The layer-by-layer modification of ≈5 nm mercaptocarboxylic acid stabilized gold nanoparticles was studied in an effort to illustrate effective means to overcome practical issues in handling and performing surface modification of such extremely small materials. To accomplish this, each layer deposition cycle was separated into a multi-step process wherein solution pH was controlled in two distinct phases of polyelectrolyte adsorption and centrifugation. Additionally, a solvent precipitation step was introduced to make processing more amenable by concentrating the sample and exchanging solution pH before ultracentrifugation. The pH-dependent assembly on gold nanoparticles was assessed after each layer deposition cycle by monitoring the plasmon peak absorbance location, surface charge, and the percentage of nanoparticles recovered. The selection of solution pH during the adsorption phase was found to be a critical parameter to enhance particle recovery and maximize surface charge when coating with weak polyelectrolytes. One bilayer was deposited with a high yield and the modified particles exhibited enhanced colloidal stability across a broad pH range and increased ionic strength. These findings support the adoption of this multi-step processing approach as an effective and generalizable approach to improve stability of high surface curvature particles. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Community Response to a Heavy Precipitation Event in High Temperature, Chemosynthetic Biofilms and Sediments

    Science.gov (United States)

    Meyer-Dombard, D. R.; Loiacono, S. T.; Shock, E.

    2012-12-01

    Coordinated analysis of the "Bison Pool" (BP) Environmental Genome and a complementary contextual geochemical dataset of ~75 parameters revealed biogeochemical cycling and metabolic and microbial community shifts in a Yellowstone National Park hot spring ecosystem (1). The >22m outflow of BP is a gradient of decreasing temperature, increasing dissolved oxygen, and changing availability of nutrients. Microbial life at BP transitions from a 92°C chemosynthetic community in the BP source pool to a 56°C photosynthetic mat community. Metagenomic data at BP showed the potential for both heterotrophic and autotrophic carbon metabolism (rTCA and acetyl-CoA cycles) in the highest temperature, chemosynthetic regions (1). This region of the outflow is dominated by Aquificales and Pyrococcus relatives, with smaller contributions of heterotrophic Bacteria. Following a 2h heavy precipitation event we observed an influx of exogenous organic material into the source pool supplied from the meadow surrounding the BP area. We sampled biomass and fluid at several locations within the outflow immediately following the event, and on several occasions for the next eight days. Elemental analysis and carbon and nitrogen isotopic analyses were conducted on biomass and sediment, and dissolved organic and inorganic carbon content and δ13C of fluids were analyzed. DNA and RNA were extracted, and following RT-PCR, nitrogen cycle functional gene expression was evaluated. Previous work at BP has shown that chemosynthetic biomass may carry isotopic signatures of fractionation during carbon fixation, via the acetyl-CoA and rTCA cycles (2). However, the addition of exogenous organic carbon during the rain event had an immediate and dramatic effect on the sediments and biofilms in the chemosynthetic zone of the outflow. Dissolved organic carbon was the highest measured in six years. Chemosynthetic biomass responded by incorporating the organic carbon. Carbon isotopic signatures in chemosynthetic

  3. Speciation and precipitation of heavy metals in high-metal and high-acid mine waters from the Iberian Pyrite Belt (Portugal).

    Science.gov (United States)

    Durães, Nuno; Bobos, Iuliu; da Silva, Eduardo Ferreira

    2017-02-01

    Acid mine waters (AMW) collected during high- and low-flow water conditions from the Lousal, Aljustrel, and São Domingos mining areas (Iberian Pyrite Belt) were physicochemically analyzed. Speciation calculation using PHREEQC code confirms the predominance of Me n+ and Me-SO 4 species in AMW samples. Higher concentration of sulfate species (Me-SO 4 ) than free ion species (Me n+ , i.e., Al, Fe, and Pb) were found, whereas opposite behavior is verified for Mg, Cu, and Zn. A high mobility of Zn than Cu and Pb was identified. The sulfate species distribution shows that Fe 3+ -SO 4 2- , SO 4 2- , HSO 4 - , Al-SO 4 , MgSO 4 0 , and CaSO 4 0 are the dominant species, in agreement with the simple and mixed metal sulfates and oxy-hydroxysulphates precipitated from AMW. The saturation indices (SI) of melanterite and epsomite show a positive correlation with Cu and Zn concentrations in AMW, which are frequently retained in simple metal sulfates. Lead is well correlated with jarosite and alunite (at least in very acid conditions) than with simple metal sulfates. The Pb for K substitution in jarosite occurs as increasing Pb concentration in solution. Lead mobility is also controlled by anglesite precipitation (a fairly insoluble sulfate), where a positive correlation was ascertained when the SI approaches equilibrium. The zeta potential of AMW decreased as pH increased due to colloidal particles aggregation, where water species change from SO 4 2- to OH - species during acid to alkaline conditions, respectively. The AMW samples were supersaturated in schwertmannite and goethite, confirmed by the Me n+ -SO 4 , Me n+ -Fe-O-OH, or Me n+ -S-O-Fe-O complexes identified by attenuated total reflectance infrared spectroscopy (ATR-IR). The ATR-IR spectrum of an AMW sample with pH 3.5 (sample L1) shows well-defined vibration plans attributed to SO 4 tetrahedron bonded with Fe-(oxy)hydroxides and the Me n+ sorbed by either SO 4 or Fe-(oxy)hydroxides. For samples with lower pH values (p

  4. Exceedance probability of the standardized precipitation-evapotranspiration index in the Texas High Plains

    Science.gov (United States)

    Drought is a common occurrence in many arid and semi-arid regions that can have large negative impacts on water resources and agricultural production. Since agricultural drought is affected by both water supply and demand (precipitation and evapotranspiration), it is beneficial to include both in a...

  5. Studies of influence of high temperature preannealing on oxygen precipitation in CZ Si wafers

    Czech Academy of Sciences Publication Activity Database

    Meduňa, M.; Caha, O.; Buršík, Jiří

    2012-01-01

    Roč. 348, č. 1 (2012), s. 53-59 ISSN 0022-0248 R&D Projects: GA ČR(CZ) GA202/09/1013 Institutional research plan: CEZ:AV0Z20410507 Keywords : impurities * point defects * precipitates Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.552, year: 2012

  6. Precipitation regions on the Earth of high energy electrons, injected by a point source moving along a circular Earth orbit

    Science.gov (United States)

    Kolesnikov, E. K.; Klyushnikov, G. N.

    2018-05-01

    In the paper we continue the study of precipitation regions of high-energy charged particles, carried out by the authors since 2002. In contrast to previous papers, where a stationary source of electrons was considered, it is assumed that the source moves along a low circular near-earth orbit with a constant velocity. The orbit position is set by the inclination angle of the orbital plane to the equatorial plane and the longitude of the ascending node. The total number of injected electrons is determined by the source strength and the number of complete revolutions that the source makes along the circumference. Construction of precipitation regions is produced using the computational algorithm based on solving of the system of ordinary differential equations. The features of the precipitation regions structure for the dipole approximation of the geomagnetic field and the symmetrical arrangement of the orbit relative to the equator are noted. The dependencies of the precipitation regions on different orbital parametres such as the incline angle, the ascending node position and kinetic energy of injected particles have been considered.

  7. [Removal of high-abundance proteins in plasma of the obese by improved TCA/acetone precipitation method].

    Science.gov (United States)

    Wang, Jun; Feng, Liru; Yu, Wei; Xu, Jian; Yang, Hui; Liu, Xiaoli

    2013-09-01

    To develop an improved trichloroacetic acid (TCA)/acetone precipitation method for removal of high-abundance proteins in plasma of the obese. Volumes of TCA/acetone solution (1, 3, 4, 5, 6, 8, 10 and 20 times of the sample) and concentrations of TCA (10%, 30%, 50%, 60%, 70% TCA/acetone solution) have been investigated to optimize the conditions of sample preparation. SDS-PAGE were used to separate and tested proteins in the supernatant and sediment. The best concentration of the TCA/acetone solution was first determined by SDS-PAGE. The protein in precipitation from 10% TCA/acetone solution processing and the new determined concentration TCA/acetone solution processing were verified by 2-D-SDS-PAGE. And then the digested products of the protein in precipitation and supernatant by trypsin were analyzed by nano HPLC-Chip-MS/MS to verify which is the best concentration to process the plasma. The best volume of TCA/acetone is four times to sample, which less or more TCA/acetone would reduce the removal efficiency of high-abundance proteins. The concentration of TCA in acetone solution should be 60%, which may remove more high-abundance proteins in plasma than 10%, 30%, 50% TCA in acetone solution. If the TCA concentration is more than 60%, the reproducibility will be much poorer due to fast precipitation of proteins. The results of mass identification showed that human plasma prepared with 60% TCA/acetone (4 times sample volume) could be verified more low-abundance proteins than 10%. The most desirable conditions for removal of high-abundance proteins in plasma is 60% TCA/acetone (4 times sample volume), especially for the plasma of obesity.

  8. Hyper-resolution urban flood modeling using high-resolution radar precipitation and LiDAR data

    Science.gov (United States)

    Noh, S. J.; Lee, S.; Lee, J.; Seo, D. J.

    2016-12-01

    Floods occur most frequently among all natural hazards, often causing widespread economic damage and loss of human lives. In particular, urban flooding is becoming increasingly costly and difficult to manage with a greater concentration of population and assets in urban centers. Despite of known benefits for accurate representation of small scale features and flow interaction among different flow domains, which have significant impact on flood propagation, high-resolution modeling has not been fully utilized due to expensive computation and various uncertainties from model structure, input and parameters. In this study, we assess the potential of hyper-resolution hydrologic-hydraulic modeling using high-resolution radar precipitation and LiDAR data for improved urban flood prediction and hazard mapping. We describe a hyper-resolution 1D-2D coupled urban flood model for pipe and surface flows and evaluate the accuracy of the street-level inundation information produced. For detailed geometric representation of urban areas and for computational efficiency, we use 1 m-resolution topographical data, processed from LiDAR measurements, in conjunction with adaptive mesh refinement. For street-level simulation in large urban areas at grid sizes of 1 to 10 m, a hybrid parallel computing scheme using MPI and openMP is also implemented in a high-performance computing system. The modeling approach developed is applied for the Johnson Creek Catchment ( 40 km2), which makes up the Arlington Urban Hydroinformatics Testbed. In addition, discussion will be given on availability of hyper-resolution simulation archive for improved real-time flood mapping.

  9. G phase precipitation and strengthening in ultra-high strength ferritic steels: Towards lean ‘maraging’ metallurgy

    International Nuclear Information System (INIS)

    Sun, W.W.; Marceau, R.K.W.; Styles, M.J.; Barbier, D.; Hutchinson, C.R.

    2017-01-01

    Ultra-high strength steels are interesting materials for light-weighting applications in the transportation industries. A key requirement of these applications is weldability and consequently a low carbon content is desirable. Maraging steels are examples of ultra-high strength, low carbon steels but their disadvantage is their high cost due to the large Ni and/or Co additions required. This contribution is focussed on the development of steels with maraging-like strengths but with low solute contents (less than 10%). A series of alloy compositions were designed to exploit precipitation of the G phase in a ferritic matrix at temperatures of 450–600 °C in order to obtain yield strengths in excess of 2 GPa. The mechanical response of the materials was measured using tension and compression testing and the precipitate evolution has been characterized using atom probe tomography (APT) and in-situ small angle X-ray scattering (SAXS) at a synchrotron beamline. Precipitate number densities of 10"2"5 m"−"3 are obtained, which are amongst the highest number densities so far observed in engineering alloys. The intrinsic strength of the G phase is shown to be proportional to its size, and deviations in the chemistry of the precipitates do not significantly affect their strengthening behaviour. An important outcome is that the common temper embrittlement issues known to occur during aging of martensite in the 450–600 °C range were mitigated in one alloy by starting with a cold-rolled and partially fragmented lath martensite instead of a freshly quenched martensite.

  10. Stable and unstable fatigue crack propagation during high temperature creep-fatigue in austenitic steels: the role of precipitation

    International Nuclear Information System (INIS)

    Lloyd, G.J.; Wareing, J.

    1979-01-01

    The distinction between stable and unstable fatigue crack propagation during high temperature creep-fatigue in austenitic stainless steels is introduced. The transition from one class of behavior to the other is related to the precipitate distribution and to the nature of the prevailing crack path. It is shown by reference to new studies and examples drawn from the literature that this behavior is common to both high strain and predominantly elastic fatigue in austenitic stainless steels. The relevance of this distinction to a mechanistic approach to high temperature plant design is discussed

  11. Disdrometer-based C-Band Radar Quantitative Precipitation Estimation (QPE) in a highly complex terrain region in tropical Colombia.

    Science.gov (United States)

    Sepúlveda, J.; Hoyos Ortiz, C. D.

    2017-12-01

    An adequate quantification of precipitation over land is critical for many societal applications including agriculture, hydroelectricity generation, water supply, and risk management associated with extreme events. The use of rain gauges, a traditional method for precipitation estimation, and an excellent one, to estimate the volume of liquid water during a particular precipitation event, does not allow to fully capture the highly spatial variability of the phenomena which is a requirement for almost all practical applications. On the other hand, the weather radar, an active remote sensing sensor, provides a proxy for rainfall with fine spatial resolution and adequate temporary sampling, however, it does not measure surface precipitation. In order to fully exploit the capabilities of the weather radar, it is necessary to develop quantitative precipitation estimation (QPE) techniques combining radar information with in-situ measurements. Different QPE methodologies are explored and adapted to local observations in a highly complex terrain region in tropical Colombia using a C-Band radar and a relatively dense network of rain gauges and disdrometers. One important result is that the expressions reported in the literature for extratropical locations are not representative of the conditions found in the tropical region studied. In addition to reproducing the state-of-the-art techniques, a new multi-stage methodology based on radar-derived variables and disdrometer data is proposed in order to achieve the best QPE possible. The main motivation for this new methodology is based on the fact that most traditional QPE methods do not directly take into account the different uncertainty sources involved in the process. The main advantage of the multi-stage model compared to traditional models is that it allows assessing and quantifying the uncertainty in the surface rain rate estimation. The sub-hourly rainfall estimations using the multi-stage methodology are realistic

  12. Assessment of the Latest GPM-Era High-Resolution Satellite Precipitation Products by Comparison with Observation Gauge Data over the Chinese Mainland

    Directory of Open Access Journals (Sweden)

    Shaowei Ning

    2016-10-01

    Full Text Available The Global Precipitation Mission (GPM Core Observatory that was launched on 27 February 2014 ushered in a new era for estimating precipitation from satellites. Based on their high spatial–temporal resolution and near global coverage, satellite-based precipitation products have been applied in many research fields. The goal of this study was to quantitatively compare two of the latest GPM-era satellite precipitation products (GPM IMERG and GSMap-Gauge Ver. 6 with a network of 840 precipitation gauges over the Chinese mainland. Direct comparisons of satellite-based precipitation products with rain gauge observations over a 20 month period from April 2014 to November 2015 at 0.1° and daily/monthly resolutions showed the following results: Both of the products were capable of capturing the overall spatial pattern of the 20 month mean daily precipitation, which was characterized by a decreasing trend from the southeast to the northwest. GPM IMERG overestimated precipitation by approximately 0.09 mm/day while GSMap-Gauge Ver. 6 underestimated precipitation by −0.04 mm/day. The two satellite-based precipitation products performed better over wet southern regions than over dry northern regions. They also showed better performance in summer than in winter. In terms of mean error, root mean square error, correlation coefficient, and probability of detection, GSMap-Gauge was better able to estimate precipitation and had more stable quality results than GPM IMERG on both daily and monthly scales. GPM IMERG was more sensitive to conditions of no rain or light rainfall and demonstrated good capability of capturing the behavior of extreme precipitation events. Overall, the results revealed some limitations of these two latest satellite-based precipitation products when used over the Chinese mainland, helping to characterize some of the error features in these datasets for potential users.

  13. Assessment of Evolving TRMM-Based Real-Time Precipitation Estimation Methods and Their Impacts on Hydrologic Prediction in a High-Latitude Basin

    Science.gov (United States)

    Yong, Bin; Hong, Yang; Ren, Li-Liang; Gourley, Jonathan; Huffman, George J.; Chen, Xi; Wang, Wen; Khan, Sadiq I.

    2013-01-01

    The real-time availability of satellite-derived precipitation estimates provides hydrologists an opportunity to improve current hydrologic prediction capability for medium to large river basins. Due to the availability of new satellite data and upgrades to the precipitation algorithms, the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis real-time estimates (TMPA-RT) have been undergoing several important revisions over the past ten years. In this study, the changes of the relative accuracy and hydrologic potential of TMPA-RT estimates over its three major evolving periods were evaluated and inter-compared at daily, monthly and seasonal scales in the high-latitude Laohahe basin in China. Assessment results show that the performance of TMPA-RT in terms of precipitation estimation and streamflow simulation was significantly improved after 3 February 2005. Overestimation during winter months was noteworthy and consistent, which is suggested to be a consequence from interference of snow cover to the passive microwave retrievals. Rainfall estimated by the new version 6 of TMPA-RT starting from 1 October 2008 to present has higher correlations with independent gauge observations and tends to perform better in detecting rain compared to the prior periods, although it suffers larger mean error and relative bias. After a simple bias correction, this latest dataset of TMPA-RT exhibited the best capability in capturing hydrologic response among the three tested periods. In summary, this study demonstrated that there is an increasing potential in the use of TMPA-RT in hydrologic streamflow simulations over its three algorithm upgrade periods, but still with significant challenges during the winter snowing events.

  14. Detecting Climate Signals in Precipitation Extremes from TRMM (1998-2013) - Increasing Contrast Between Wet and Dry Extremes During the "Global Warming Hiatus"

    Science.gov (United States)

    Wu, Huey-Tzu Jenny; Lau, William K.-M.

    2016-01-01

    We investigate changes in daily precipitation extremes using Tropical Rainfall Measuring Mission (TRMM) data (1998-2013), which coincides with the "global warming hiatus." Results show a change in probability distribution functions of local precipitation events (LPEs) during this period consistent with previous global warming studies, indicating increasing contrast between wet and dry extremes, with more intense LPE, less moderate LPE, and more dry (no rain) days globally. Analyses for land and ocean separately reveal more complex and nuanced changes over land, characterized by a strong positive trend (+12.0% per decade, 99% confidence level (c.l.)) in frequency of extreme LPEs over the Northern Hemisphere extratropics during the wet season but a negative global trend (-6.6% per decade, 95% c.l.) during the dry season. A significant global drying trend (3.2% per decade, 99% c.l.) over land is also found during the dry season. Regions of pronounced increased dry events include western and central U.S., northeastern Asia, and Southern Europe/Mediterranean.

  15. Regional interdependency of precipitation indices across Denmark in two ensembles of high-resolution RCMs

    DEFF Research Database (Denmark)

    Sunyer Pinya, Maria Antonia; Madsen, Henrik; Rosbjerg, Dan

    2013-01-01

    all these methods is that the climate models are independent. This study addresses the validity of this assumption for two ensembles of regional climate models (RCMs) from the Ensemble-Based Predictions of Climate Changes and their Impacts (ENSEMBLES) project based on the land cells covering Denmark....... Daily precipitation indices from an ensemble of RCMs driven by the 40-yrECMWFRe-Analysis (ERA-40) and an ensemble of the same RCMs driven by different general circulation models (GCMs) are analyzed. Two different methods are used to estimate the amount of independent information in the ensembles....... These are based on different statistical properties of a measure of climate model error. Additionally, a hierarchical cluster analysis is carried out. Regardless of the method used, the effective number of RCMs is smaller than the total number of RCMs. The estimated effective number of RCMs varies depending...

  16. Influence of ruthenium ions on the precipitation of α-FeOOH, α-Fe2O3 and Fe3O4 in highly alkaline media

    International Nuclear Information System (INIS)

    Krehula, Stjepko; Music, Svetozar

    2006-01-01

    The influence of ruthenium ions on the precipitation of goethite (α-FeOOH), α-Fe 2 O 3 and Fe 3 O 4 in highly alkaline media was investigated by 57 Fe Moessbauer and FT-IR spectroscopies, thermal field emission scanning electron microscope (FE SEM) and EDS. The presence of Ru-dopant strongly affected the precipitation of α-FeOOH at highly alkaline pH, i.e. the formation of α-Fe 2 O 3 was also noticed. A decrease of hyperfine magnetic field (HMF) at RT from 35.1 T (undoped α-FeOOH) to 31.3 T for sample with [Ru]/([Ru] + [Fe]) = 0.0196 was assigned to the incorporation of ruthenium ions into the α-FeOOH structure. Moessbauer spectroscopy showed the formation of stoichiometric Fe 3 O 4 for [Ru]/([Ru] + [Fe]) = 0.0291-0.0909. α-Fe 2 O 3 and Fe 3 O 4 did not show a tendency to the formation of solid solutions with ruthenium ions. FE SEM observations of the samples showed that reference α-FeOOH sample contained acicular particles of good uniformity, which increased the length up to ∼5 times with increase of concentration of ruthenium ions. On the other hand, large octahedral Fe 3 O 4 crystals (particles) were associated with small particles of ruthenium (hydrous) oxide with a size in the range ∼100 nm or less. A possible catalytic action of ruthenium that created reduction conditions for Fe 3+ ions and formation of Fe 2+ ions for precipitation of Fe 3 O 4 was discussed

  17. Ultrafine grain formation in Mg–Zn alloy by in situ precipitation during high-pressure torsion

    International Nuclear Information System (INIS)

    Meng, Fanqiang; Rosalie, Julian M.; Singh, Alok; Somekawa, Hidetoshi; Tsuchiya, Koichi

    2014-01-01

    A ultrafine-grained structure was produced in a Mg–3.4Zn (at.%) alloy subjected to high-pressure torsion (HPT) at ambient temperature. Hardness and X-ray diffraction measurements indicated the microstructure reached a steady state after three revolutions. Transmission electron microscopy observations showed equiaxed, dynamically recrystallized grains with an average diameter of 140 nm after 20 revolutions, substantially less than the steady-state grain size in pure Mg deformed by HPT. This is attributed to the formation of precipitates during processing, which impedes the growth of recrystallized grains

  18. Study on the Key Technology of High Purity Strontium Titanate Powder Synthesized from Oxalic Acid Co-sediment Precipitation

    Science.gov (United States)

    Bi, Xiaoguo; Dong, Yingnan; Li, Yingjie; Niu, Wei; Tang, Jian; Ding, Shuang; Li, Meiyang

    2017-09-01

    Oxalate coprecipitation is applied in this paper, high purity titanium tetrachloride, and after the purification of strontium chloride, match with a certain concentration of solution, oxalate and strontium chloride and titanium tetrachloride in 1.005:1.000 make strontium titanium mixture ratio, slowly under 60°C to join in oxalic acid solution, aging around 4 h, get oxygen titanium strontium oxalate (SrTiO(C2O4)2 • 4H2 ) precipitation, after washing, drying and other process made oxygen titanium strontium oxalate powder.

  19. Permeability change with dissolution and precipitation reaction induced by highly alkaline plume in packed bed with amorphous silica particles

    International Nuclear Information System (INIS)

    Komatsu, Kyo; Kadowaki, Junichi; Niibori, Yuichi; Mimura, Hitoshi; Usui, Hideo

    2008-01-01

    A large amount of cement is used to construct of the geological disposal system. Such a material alters the pH of groundwater to highly alkaline region. The highly alkaline plume contains rich Ca ion compared to the surrounding environment, and the Ca ion reacts with soluble silicic acid. Its product would deposit on the surface of flow-paths in the natural barrier and decrease the permeability. In this study, the influence of Ca ions in highly alkaline plume on flow-paths has been examined by using packed bed column. The column was packed with the amorphous silica particles of 75-150 μm in diameter. The Ca(OH) 2 solution (0.78 mM, 2.58 mM, 4.37 mM, and 8.48 mM, pH: 12.2-12.4) was continuously injected into the column at a constant flow rate (5 ml/min, and 2 ml/min), and the change of permeability was monitored. At the same time, the concentrations of [Ca] total and [Si] in the eluted solution were measured by the inductively coupled plasma atomic emission spectrometry (ICP-AES). The Ca(OH) 2 solutions were prepared with CO 2 -free pure water, and filtrated through 0.45 μm filter. The permeability was normalized by the initial permeability value. In the experiment results, the permeability dramatically changed with increasing Ca concentration, because Ca ions and H 4 SiO 4 (due to the dissolution of SiO 2 ) produce C-S-H gel between the packed particles in the column. The SEM images and XRD analyses showed that the surface of SiO 2 particles was covered with the C-S-H gel precipitation. On the other hand, when the Ca concentration was relatively low, the permeability did not show remarkable change. For the cross section of SiO 2 particles, EPMA analysis suggested the consumption of Ca in the inner pore of the SiO 2 particles. However, the time-change in the concentrations of Si and Ca was not always simple. Such time-change strongly depended not only on pH or Ca concentration, but also on the flow rates. This suggested that mass transport controls the chemical

  20. Increased strength of concrete subject to high loading rates

    International Nuclear Information System (INIS)

    Curbach, M.

    1987-01-01

    Within the scope of this work various problems are discussed which occur in connection with concrete under high tensile loading rates (e.g. when a plane crashes on a nuclear power plant very high loads occur which act only for a very short time). Particularly the causes for the already frequently noticed increases in strength with increasing loading rates are investigated and also the question whether this increased strength can be taken into account when dimensioning a construction. (MM) [de

  1. Warm season precipitation signal in δ2 H values of wood lignin methoxyl groups from high elevation larch trees in Switzerland.

    Science.gov (United States)

    Riechelmann, Dana F C; Greule, Markus; Siegwolf, Rolf T W; Anhäuser, Tobias; Esper, Jan; Keppler, Frank

    2017-10-15

    In this study, we tested stable hydrogen isotope ratios of wood lignin methoxyl groups (δ 2 H methoxyl values) as a palaeoclimate proxy in dendrochronology. This is a quite new method in the field of dendrochronology and the sample preparation is much simpler than the methods used before to measure δ 2 H values from wood. We measured δ 2 H methoxyl values in high elevation larch trees (Larix decidua Mill.) from Simplon Valley (southern Switzerland). Thirty-seven larch trees were sampled and five individuals analysed for their δ 2 H methoxyl values at annual (1971-2009) and pentadal resolution (1746-2009). The δ 2 H methoxyl values were measured as CH 3 I released upon treatment of the dried wood samples with hydroiodic acid. 10-90 μL from the head-space were injected into the gas chromatography/high-temperature conversion/isotope ratio mass spectrometry (GC/HTC-IRMS) system. Testing the climate response of the δ 2 H methoxyl values, the annually resolved series show a positive correlation of r = 0.60 with June/July precipitation. The pentadally resolved δ 2 H methoxyl series do not show any significant correlation to climate parameters. Increased precipitation during June and July, which are on average warm and relatively dry months, results in higher δ 2 H values of the xylem water and, therefore, higher δ 2 H values in the lignin methoxyl groups. Therefore, we suggest that δ 2 H methoxyl values of high elevation larch trees might serve as a summer precipitation proxy. Copyright © 2017 John Wiley & Sons, Ltd.

  2. The influence of a Cr-dopant on the properties of α-FeOOH particles precipitated in highly alkaline media

    International Nuclear Information System (INIS)

    Krehula, Stjepko; Music, Svetozar

    2009-01-01

    The effects of a Cr-dopant on the precipitation of acicular α-FeOOH particles, the formation of solid solutions, particle size and shape were investigated using X-ray powder diffraction (XRD), Moessbauer and Fourier transform infrared (FT-IR) spectroscopies and field emission scanning electron microscopy (FE-SEM). Acicular and monodisperse α-FeOOH particles were precipitated at a very high pH by heating the suspension obtained by adding a tetramethylammonium hydroxide solution to an aqueous solution of FeCl 3 . The influence of the Cr-dopant was investigated by addition of various amounts of Cr 3+ ions to the initial FeCl 3 solution, where r = 100[Cr]/([Cr] + [Fe]) stands for the added amount of Cr. XRD analysis of the obtained powders (with r values from 0 to 23.08) showed only the presence of the diffraction lines characteristic for α-FeOOH. Moessbauer spectroscopy showed a decrease in hyperfine magnetic field of α-FeOOH with an increase in Cr addition which indicates Cr incorporation into the α-FeOOH structure. The OH bending bands in the FT-IR spectra showed only a slight change in position with an increase in r, but the considerable increase in the lattice band wave number indicated a decrease in thickness of the lath-like α-FeOOH particles. This conclusion was confirmed by FE-SEM observations

  3. Fine-scale precipitation and mechanical properties of thin slab processed titanium-niobium bearing high strength steels

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Z. [Center for Structural and Functional Materials, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA 70503 (United States); Misra, R.D.K., E-mail: dmisra@louisiana.edu [Center for Structural and Functional Materials, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA 70503 (United States); O' Malley, R. [Nucor Steel Decatur, LLC, 4301 Iverson Blvd., Trinity, AL 35673 (United States); Jansto, S.J. [CBMM-Reference Metals Company, 1000 Old Pond Road, Bridgeville, PA 15017 (United States)

    2011-08-25

    Highlights: {yields} Precipitation and mechanical behavior of Ti-Nb and Ti-Nb-Mo-V steels were elucidated. {yields} Distribution of precipitates was analyzed with microscopy and diffraction pattern. {yields} During austenite-ferrite transformation, interface precipitation of NbC was observed. {yields} Epitaxial precipitation of NbC on TiC surface results in mixed precipitates Ti(Nb)C. - Abstract: We describe here the precipitation behavior and mechanical properties of 560 MPa Ti-Nb and 770 MPa Ti-Nb-Mo-V steels. The precipitation characteristics were analyzed in terms of chemistry and size distribution of precipitates, with particular focus on the crystallography of precipitates through an analysis of electron diffraction patterns. In addition to pure carbides (NbC, TiC, Mo{sub 2}C, and VC), Nb containing titanium-rich carbides were also observed. These precipitates were of a size range of 4-20 nm. The mechanism of formation of these Ti-rich niobium containing carbides is postulated to involve epitaxial nucleation of NbC on previously precipitated TiC. Interface precipitation of NbC was an interesting observation in compact strip processing which is characterized by an orientation relationship of [0 0 1]{sub NbC}//[0 0 1]{sub {alpha}-Fe}, implying that the precipitation of NbC occurred during austenite-ferrite transformation.

  4. Fine-scale precipitation and mechanical properties of thin slab processed titanium-niobium bearing high strength steels

    International Nuclear Information System (INIS)

    Jia, Z.; Misra, R.D.K.; O'Malley, R.; Jansto, S.J.

    2011-01-01

    Highlights: → Precipitation and mechanical behavior of Ti-Nb and Ti-Nb-Mo-V steels were elucidated. → Distribution of precipitates was analyzed with microscopy and diffraction pattern. → During austenite-ferrite transformation, interface precipitation of NbC was observed. → Epitaxial precipitation of NbC on TiC surface results in mixed precipitates Ti(Nb)C. - Abstract: We describe here the precipitation behavior and mechanical properties of 560 MPa Ti-Nb and 770 MPa Ti-Nb-Mo-V steels. The precipitation characteristics were analyzed in terms of chemistry and size distribution of precipitates, with particular focus on the crystallography of precipitates through an analysis of electron diffraction patterns. In addition to pure carbides (NbC, TiC, Mo 2 C, and VC), Nb containing titanium-rich carbides were also observed. These precipitates were of a size range of 4-20 nm. The mechanism of formation of these Ti-rich niobium containing carbides is postulated to involve epitaxial nucleation of NbC on previously precipitated TiC. Interface precipitation of NbC was an interesting observation in compact strip processing which is characterized by an orientation relationship of [0 0 1] NbC //[0 0 1] α-Fe , implying that the precipitation of NbC occurred during austenite-ferrite transformation.

  5. Potential for added value in precipitation simulated by high-resolution nested Regional Climate Models and observations

    Energy Technology Data Exchange (ETDEWEB)

    Di Luca, Alejandro; Laprise, Rene [Universite du Quebec a Montreal (UQAM), Centre ESCER (Etude et Simulation du Climat a l' Echelle Regionale), Departement des Sciences de la Terre et de l' Atmosphere, PK-6530, Succ. Centre-ville, B.P. 8888, Montreal, QC (Canada); De Elia, Ramon [Universite du Quebec a Montreal, Ouranos Consortium, Centre ESCER (Etude et Simulation du Climat a l' Echelle Regionale), Montreal (Canada)

    2012-03-15

    Regional Climate Models (RCMs) constitute the most often used method to perform affordable high-resolution regional climate simulations. The key issue in the evaluation of nested regional models is to determine whether RCM simulations improve the representation of climatic statistics compared to the driving data, that is, whether RCMs add value. In this study we examine a necessary condition that some climate statistics derived from the precipitation field must satisfy in order that the RCM technique can generate some added value: we focus on whether the climate statistics of interest contain some fine spatial-scale variability that would be absent on a coarser grid. The presence and magnitude of fine-scale precipitation variance required to adequately describe a given climate statistics will then be used to quantify the potential added value (PAV) of RCMs. Our results show that the PAV of RCMs is much higher for short temporal scales (e.g., 3-hourly data) than for long temporal scales (16-day average data) due to the filtering resulting from the time-averaging process. PAV is higher in warm season compared to cold season due to the higher proportion of precipitation falling from small-scale weather systems in the warm season. In regions of complex topography, the orographic forcing induces an extra component of PAV, no matter the season or the temporal scale considered. The PAV is also estimated using high-resolution datasets based on observations allowing the evaluation of the sensitivity of changing resolution in the real climate system. The results show that RCMs tend to reproduce relatively well the PAV compared to observations although showing an overestimation of the PAV in warm season and mountainous regions. (orig.)

  6. The influence of Zn-dopant on the precipitation of α-FeOOH in highly alkaline media

    International Nuclear Information System (INIS)

    Krehula, Stjepko; Music, Svetozar; Skoko, Zeljko; Popovic, Stanko

    2006-01-01

    The influence of Zn-dopant on the precipitation of α-FeOOH in highly alkaline media was monitored by X-ray diffraction (XRD), 57 Fe Moessbauer and Fourier transform infrared (FT-IR) spectroscopies and field emission scanning electron microscopy (FE SEM). Acicular and monodisperse α-FeOOH particles were precipitated at a very high pH by adding a tetramethylammonium hydroxide solution to an aqueous solution of FeCl 3 . The XRD analysis of the samples precipitated in the presence of Zn 2+ ions showed the formation of solid solutions of α-(Fe, Zn)OOH up to a concentration ratio r = [Zn]/([Zn] + [Fe]) = 0.0909. ZnFe 2 O 4 was additionally formed in the precipitate for r = 0.1111, whereas the three phases α-FeOOH, α-Fe 2 O 3 and ZnFe 2 O 4 were formed for r 0.1304. In the corresponding FT-IR spectra, the Fe-OH and Fe-O stretching bands were sensitive to the Zn 2+ substitution, whereas the Fe-OH bending bands of α-FeOOH at 892 and 796 cm -1 were almost insensitive. The Moessbauer spectra showed a high sensitivity to the formation of α-(Fe, Zn)OOH solid solutions which were monitored on the basis of a decrease in B hf values in dependence on Zn-doping. A strictly linear decrease in B hf for α-FeOOH doped with Zn 2+ ions was measured up to r = 0.0291, whereas for r = 0.0476 and higher there was a deviation from linearity. The presence of α-(Fe, Zn)OOH, α-Fe 2 O 3 and ZnFe 2 O 4 phases in the samples was determined quantitatively by Moessbauer spectroscopy. Likewise, Moessbauer spectroscopy did not show any formation of the solid solutions of α-Fe 2 O 3 with Zn 2+ ions. FE SEM showed a strong effect of Zn-doping on the elongation of acicular α-FeOOH particles (∼500-700 nm in length) up to r = 0.1111. For r = 0.1304 the sizes of ZnFe 2 O 4 particles were around 30-50 nm, and those of α-Fe 2 O 3 particles were around 500 nm, whereas a relatively small number of very elongated α-(Fe, Zn)OOH particles was observed. A possible mechanism of the formation of

  7. Influence of the Anomalous Patterns of the Mascarene and Australian Highs on Precipitation during the Prerainy Season in South China

    Directory of Open Access Journals (Sweden)

    Xue Han

    2017-01-01

    Full Text Available The authors investigate the features of precipitation during the prerainy season in South China (PSCPRS and the atmospheric circulation in the Southern Hemisphere (SH, which is expected to influence the PSCPRS significantly. The Morlet wavelet method revealed that the PSCPRS has significant interannual variability, especially in its quasi-biennial oscillation. The PSCPRS exhibits a significant monsoonal precipitation pattern. Using singular value decomposition (SVD and composite analysis, the anomalous characteristics of SH atmospheric circulations and their impacts on the PSCPRS are studied. The results reveal that eastward movements or extensions of the Mascarene high (MH and Australian high (AH, which have quasi-baroclinic geopotential height structures in the lower and middle troposphere, are the most significant factors affecting the PSCPRS. Their impacts on the PSCPRS anomalies are further studied using the index east of the MH (IEMH and index east of the AH (IEAH. The IEMH and IEAH have notable significant positive correlations with the PSCPRS. When either the IEMH or IEAH is stronger (weaker, more (less rainfall occurs during the prerainy season in South China.

  8. Increased Cardiometabolic Risk and Worsening Hypoxemia at High Altitude

    OpenAIRE

    Miele, Catherine H.; Schwartz, Alan R.; Gilman, Robert H.; Pham, Luu; Wise, Robert A.; Davila-Roman, Victor G.; Jun, Jonathan C.; Polotsky, Vsevolod Y.; Miranda, J. Jaime; Leon-Velarde, Fabiola; Checkley, William

    2016-01-01

    Miele, Catherine H., Alan R. Schwartz, Robert H. Gilman, Luu Pham, Robert A. Wise, Victor G. Davila-Roman, Jonathan C. Jun, Vsevolod Y. Polotsky, J. Jaime Miranda, Fabiola Leon-Velarde, and William Checkley. Increased cardiometabolic risk and worsening hypoxemia at high altitude. High Alt Med Biol. 17:93���100, 2016.���Metabolic syndrome, insulin resistance, diabetes, and dyslipidemia are associated with an increased risk of cardiovascular disease. While excessive erythrocytosis is associated...

  9. Evaluation of high intensity precipitation from 16 Regional climate models over a meso-scale catchment in the Midlands Regions of England

    Science.gov (United States)

    Wetterhall, F.; He, Y.; Cloke, H.; Pappenberger, F.; Freer, J.; Wilson, M.; McGregor, G.

    2009-04-01

    Local flooding events are often triggered by high-intensity rain-fall events, and it is important that these can be correctly modelled by Regional Climate Models (RCMs) if the results are to be used in climate impact assessment. In this study, daily precipitation from 16 RCMs was compared with observations over a meso-scale catchment in the Midlands Region of England. The RCM data was provided from the European research project ENSEMBLES and the precipitation data from the UK MetOffice. The RCMs were all driven by reanalysis data from the ERA40 dataset over the time period 1961-2000. The ENSEMBLES data is on the spatial scale of 25 x 25 km and it was disaggregated onto a 5 x 5 km grid over the catchment and compared with interpolated observational data with the same resolution. The mean precipitation was generally underestimated by the ENSEMBLES data, and the maximum and persistence of high intensity rainfall was even more underestimated. The inter-annual variability was not fully captured by the RCMs, and there was a systematic underestimation of precipitation during the autumn months. The spatial pattern in the modelled precipitation data was too smooth in comparison with the observed data, especially in the high altitudes in the western part of the catchment where the high precipitation usually occurs. The RCM outputs cannot reproduce the current high intensity precipitation events that are needed to sufficiently model extreme flood events. The results point out the discrepancy between climate model output and the high intensity precipitation input needs for hydrological impact modelling.

  10. High spatial-temporal resolution and integrated surface and subsurface precipitation-runoff modelling for a small stormwater catchment

    Science.gov (United States)

    Hailegeorgis, Teklu T.; Alfredsen, Knut

    2018-02-01

    Reliable runoff estimation is important for design of water infrastructure and flood risk management in urban catchments. We developed a spatially distributed Precipitation-Runoff (P-R) model that explicitly represents the land cover information, performs integrated modelling of surface and subsurface components of the urban precipitation water cycle and flow routing. We conducted parameter calibration and validation for a small (21.255 ha) stormwater catchment in Trondheim City during Summer-Autumn events and season, and snow-influenced Winter-Spring seasons at high spatial and temporal resolutions of respectively 5 m × 5 m grid size and 2 min. The calibration resulted in good performance measures (Nash-Sutcliffe efficiency, NSE = 0.65-0.94) and acceptable validation NSE for the seasonal and snow-influenced periods. The infiltration excess surface runoff dominates the peak flows while the contribution of subsurface flow to the sewer pipes also augments the peak flows. Based on the total volumes of simulated flow in sewer pipes (Qsim) and precipitation (P) during the calibration periods, the Qsim/P ranges from 21.44% for an event to 56.50% for the Winter-Spring season, which are in close agreement with the observed volumes (Qobs/P). The lowest percentage of precipitation volume that is transformed to the total simulated runoff in the catchment (QT) is 79.77%. Computation of evapotranspiration (ET) indicated that the ET/P is less than 3% for the events and snow-influenced seasons while it is about 18% for the Summer-Autumn season. The subsurface flow contribution to the sewer pipes are markedly higher than the total surface runoff volume for some events and the Summer-Autumn season. The peakiest flow rates correspond to the Winter-Spring season. Therefore, urban runoff simulation for design and management purposes should include two-way interactions between the subsurface runoff and flow in sewer pipes, and snow-influenced seasons. The developed urban P-R model is

  11. Future changes of precipitation characteristics in China

    Science.gov (United States)

    Wu, S.; Wu, Y.; Wen, J.

    2017-12-01

    Global warming has the potential to alter the hydrological cycle, with significant impacts on the human society, the environment and ecosystems. This study provides a detailed assessment of potential changes in precipitation characteristics in China using a suite of 12 high-resolution CMIP5 climate models under a medium and a high Representative Concentration Pathways: RCP4.5 and RCP8.5. We examine future changes over the entire distribution of precipitation, and identify any shift in the shape and/or scale of the distribution. In addition, we use extreme-value theory to evaluate the change in probability and magnitude for extreme precipitation events. Overall, China is going to experience an increase in total precipitation (by 8% under RCP4.5 and 12% under RCP8.5). This increase is uneven spatially, with more increase in the west and less increase in the east. Precipitation frequency is projected to increase in the west and decrease in the east. Under RCP4.5, the overall precipitation frequency for the entire China remains largely unchanged (0.08%). However, RCP8.5 projects a more significant decrease in frequency for large part of China, resulting in an overall decrease of 2.08%. Precipitation intensity is likely increase more uniformly, with an overall increase of 11% for RCP4.5 and 19% for RCP8.5. Precipitation increases for all parts of the distribution, but the increase is more for higher quantiles, i.e. strong events. The relative contribution of small quantiles is likely to decrease, whereas contribution from heavy events is likely to increase. Extreme precipitation increase at much higher rates than average precipitation, and high rates of increase are expected for more extreme events. 1-year events are likely to increase by 15%, but 20-year events are going to increase by 21% under RCP4.5, 26% and 40% respectively under RCP8.5. The increase of extreme events is likely to be more spatially uniform.

  12. Precipitation and measurements of precipitation

    NARCIS (Netherlands)

    Schmidt, F.H.; Bruin, H.A.R. de; Attmannspacher, W.; Harrold, T.W.; Kraijenhoff van de Leur, D.A.

    1977-01-01

    In Western Europe, precipitation is normal phenomenon; it is of importance to all aspects of society, particularly to agriculture, in cattle breeding and, of course, it is a subject of hydrological research. Precipitation is an essential part in the hydrological cycle. How disastrous local

  13. Antisolvent precipitation for the preparation of high polymeric procyanidin nanoparticles under ultrasonication and evaluation of their antioxidant activity in vitro.

    Science.gov (United States)

    Liu, Zaizhi; Yang, Lei

    2018-05-01

    An improved method of ultrasonic antisolvent precipitation was used to prepare micronized high polymeric procyanidins (HPC). Response surface methodology (Plackett-Burman and Box-Behnken design) was employed to predict the optimal preparation conditions and satisfactory mean particle size. Among seven parameters, three parameters (i.e., ultrasonic irradiation power, ultrasonic-stirring time, and stirring speed) were identified as the most significant variables using Plackett-Burman design; thus, these three parameters were further optimized using Box-Behnken design. The optimal preparation conditions for micronized HPC were obtained as follows: dropping speed of 4 mL/min, HPC solution concentration of 0.3 mg/mL, ratio of antisolvent and solvent of 5 mL/mL, precipitation temperature of 10 °C, ultrasonic-stirring time of 14 min, ultrasonic irradiation power of 620 W, and stirring speed of 760 r/min. A minimum mean particle size of 96 ± 2 nm was achieved under the aforementioned conditions. The obtained micronized HPC was analysed by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric and X-ray powder diffraction patterns. Micronized HPC enjoyed the higher quantity dissolved and exhibited stronger antioxidant activity in compared to the unprocessed HPC. These results demonstrated that the improved method has great potential for the production of micronized particles. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. High-resolution electron microscopy studies of the precipitation of copper under neutron irradiation in an Fe-1.3WT% Cu alloy

    International Nuclear Information System (INIS)

    Nicol, A. C.

    1998-01-01

    We have studied by electron microscopy the copper-rich precipitates in an Fe-1.3wt%Cu model alloy irradiated with neutrons to doses of 8.61 x 10 -3 dpa and 6.3 x 10 -2 dpa at a temperature of ∼270 C. In the lower dose material a majority (ca. 60%)of the precipitates visible in high-resolution electron microscopy were timed 9R precipitates of size ∼2-4 nm, while ca. 40% were untwinned. In the higher dose material, a majority (ca. 75%) of visible precipitates were untwinned although many still seemed to have a 9R structure. The average angle α between the herring-bone fringes in the twin variants was measured as 125 degree, not the 129 degree characteristic of precipitates in thermally-aged and electron-irradiated material immediately after the bcc->9R martensitic transformation. We argue that these results imply that the bcc->9R transformation of small (<4 nm) precipitates under neutron irradiation takes place at the irradiation temperature of 270 C rather than after subsequent cooling. Preliminary measurements showed that precipitate sizes did not depend strongly on dose, with a mean diameter of 3.4 ± 0.7 nm for the lower dose material, and 3.0 ± 0.5 nm for the higher dose material. This result agrees with the previous assumption that the lack of coarsening in precipitates formed under neutron irradiation is a consequence of the partial dissolution of larger precipitates by high-energy cascades

  15. Spatial downscaling algorithm of TRMM precipitation based on multiple high-resolution satellite data for Inner Mongolia, China

    Science.gov (United States)

    Duan, Limin; Fan, Keke; Li, Wei; Liu, Tingxi

    2017-12-01

    Daily precipitation data from 42 stations in Inner Mongolia, China for the 10 years period from 1 January 2001 to 31 December 2010 was utilized along with downscaled data from the Tropical Rainfall Measuring Mission (TRMM) with a spatial resolution of 0.25° × 0.25° for the same period based on the statistical relationships between the normalized difference vegetation index (NDVI), meteorological variables, and digital elevation models (https://en.wikipedia.org/wiki/Digital_elevation_model) (DEM) using the leave-one-out (LOO) cross validation method and multivariate step regression. The results indicate that (1) TRMM data can indeed be used to estimate annual precipitation in Inner Mongolia and there is a linear relationship between annual TRMM and observed precipitation; (2) there is a significant relationship between TRMM-based precipitation and predicted precipitation, with a spatial resolution of 0.50° × 0.50°; (3) NDVI and temperature are important factors influencing the downscaling of TRMM precipitation data for DEM and the slope is not the most significant factor affecting the downscaled TRMM data; and (4) the downscaled TRMM data reflects spatial patterns in annual precipitation reasonably well, showing less precipitation falling in west Inner Mongolia and more in the south and southeast. The new approach proposed here provides a useful alternative for evaluating spatial patterns in precipitation and can thus be applied to generate a more accurate precipitation dataset to support both irrigation management and the conservation of this fragile grassland ecosystem.

  16. TCA precipitation.

    Science.gov (United States)

    Koontz, Laura

    2014-01-01

    Trichloroacetic acid (TCA) precipitation of proteins is commonly used to concentrate protein samples or remove contaminants, including salts and detergents, prior to downstream applications such as SDS-PAGE or 2D-gels. TCA precipitation denatures the protein, so it should not be used if the protein must remain in its folded state (e.g., if you want to measure a biochemical activity of the protein). © 2014 Elsevier Inc. All rights reserved.

  17. STRONTIUM PRECIPITATION

    Science.gov (United States)

    McKenzie, T.R.

    1960-09-13

    A process is given for improving the precipitation of strontium from an aqueous phosphoric-acid-containing solution with nickel or cobalt ferrocyanide by simultaneously precipitating strontium or calcium phosphate. This is accomplished by adding to the ferrocyanide-containing solution calcium or strontium nitrate in a quantity to yield a concentration of from 0.004 to 0.03 and adjusting the pH of the solution to a value of above 8.

  18. Identification and root cause analysis of cell culture media precipitates in the viral deactivation treatment with high-temperature/short-time method.

    Science.gov (United States)

    Cao, Xiaolin; Stimpfl, Gregory; Wen, Zai-Qing; Frank, Gregory; Hunter, Glenn

    2013-01-01

    High-temperature/short-time (HTST) treatment of cell culture media is one of the proven techniques used in the biopharmaceutical manufacturing industry for the prevention and mitigation of media viral contamination. With the HTST method, the formulated media is pasteurized (virus-deactivated) by heating and pumping the media continuously through the preset high-temperature holding tubes to achieve a specified period of time at a specific temperature. Recently, during the evaluation and implementation of HTST method in multiple Amgen, Inc. manufacturing facilities, media precipitates were observed in the tests of HTST treatments. The media precipitates may have adverse consequences such as clogging the HTST system, altering operating conditions and compromising the efficacy of viral deactivation, and ultimately affecting the media composition and cell growth. In this study, we report the identification of the composition of media precipitates from multiple media HTST runs using combined microspectroscopic methods including Raman, Fourier transform infrared spectroscopy, and scanning electron microscopy with energy-dispersive X-ray spectroscopy. The major composition in the precipitates was determined to be metal phosphates, including calcium phosphate, magnesium phosphate, and iron (III) phosphate. Based on the composition, stoichiometry, and root-cause study of media precipitations, methods were implemented for the mitigation and prevention of the occurrence of the media precipitation. Viral contamination in cell culture media is an important issue in the biopharmaceutical manufacturing industry and may have serious consequences on product quality, efficacy, and safety. High-temperature/short-time (HTST) treatment of cell culture media is one of the proven techniques used in the industry for the prevention and mitigation of media viral contamination. With the HTST method, the formulated media is pasteurized (virus-deactivated) by heating at preset conditions. This

  19. Few apparent short-term effects of elevated soil temperature and increased frequency of summer precipitation on the abundance and taxonomic diversity of desert soil micro- and meso-fauna

    Science.gov (United States)

    Darby, B.J.; Neher, D.A.; Housman, D.C.; Belnap, J.

    2011-01-01

    Frequent hydration and drying of soils in arid systems can accelerate desert carbon and nitrogen mobilization due to respiration, microbial death, and release of intracellular solutes. Because desert microinvertebrates can mediate nutrient cycling, and the autotrophic components of crusts are known to be sensitive to rapid desiccation due to elevated temperatures after wetting events, we studied whether altered soil temperature and frequency of summer precipitation can also affect the composition of food web consumer functional groups. We conducted a two-year field study with experimentally-elevated temperature and frequency of summer precipitation in the Colorado Plateau desert, measuring the change in abundance of nematodes, protozoans, and microarthropods. We hypothesized that microfauna would be more adversely affected by the combination of elevated temperature and frequency of summer precipitation than either effect alone, as found previously for phototrophic crust biota. Microfauna experienced normal seasonal fluctuations in abundance, but the effect of elevated temperature and frequency of summer precipitation was statistically non-significant for most microfaunal groups, except amoebae. The seasonal increase in abundance of amoebae was reduced with combined elevated temperature and increased frequency of summer precipitation compared to either treatment alone, but comparable with control (untreated) plots. Based on our findings, we suggest that desert soil microfauna are relatively more tolerant to increases in ambient temperature and frequency of summer precipitation than the autotrophic components of biological soil crust at the surface.

  20. Removal of palladium precipitate from a simulated high-level radioactive liquid waste by reduction by ascorbic acid

    International Nuclear Information System (INIS)

    Kim, Eung Ho; Yoo, Jae Hyung; Choi, Cheong Song

    1998-01-01

    A study of the selective removal of Palladium from a simulated solution of high-level radioactive liquid waste (HLLW) was carried out. The simulated solution contained 7 representative elements (Pd 2+ , Cs + , Sr 2+ , Fe 3+ , MoO 2 2+ , Ru 4+ , and Nd 3+ ) typical of HLLW, ascorbic acid was added to the solution at room temperature. Pd 2+ in the simulated solution was easily reduced to Pd metal by the ascorbic acid and then the metal precipitate could be removed from the solution, whereas other elements remained mainly in solution. When the resulting Pd metal was left in solution, it was reoxidized to Pb 2+ ion and redissolved in a nitric acid medium. The oxidation rate of Pd 2+ depended on the presence of a transition metal such as ferric ion, and was also in proportion to the concentration of nitric acid and in inverse proportion to the concentration of ascrobic acid. (orig.)

  1. γ' Precipitation Study of a Co-Ni-Based Alloy

    Science.gov (United States)

    Locq, D.; Martin, M.; Ramusat, C.; Fossard, F.; Perrut, M.

    2018-05-01

    A Co-Ni-based alloy strengthened by γ'-(L12) precipitates was utilized to investigate the precipitation evolution after various cooling rates and several aging conditions. In this study, the precipitate size and volume fraction have been studied via scanning electron microscopy and transmission electron microscopy. The influence of the precipitation evolution was measured via microhardness tests. The cooling rate study shows a more sluggish γ' precipitation reaction compared to that observed in a Ni-based superalloy. Following a rapid cooling rate, the application of appropriate double aging treatments allows for the increase of the γ' volume fraction as well as the control of the size and distribution of the precipitates. The highest hardness values reach those measured on supersolvus cast and wrought Ni-based superalloys. The observed γ' precipitation behavior should have implications for the production, the heat treatment, the welding, or the additive manufacturing of this new class of high-temperature materials.

  2. The relationships between precipitation, convective cloud and tropical cyclone intensity change

    Science.gov (United States)

    Ruan, Z.; Wu, Q.

    2017-12-01

    Using 16 years precipitation, brightness temperature (IR BT) data and tropical cyclone (TC) information, this study explores the relationship between precipitation, convective cloud and tropical cyclone (TC) intensity change in the Western North Pacific Ocean. It is found that TC intensity has positive relation with TC precipitation. TC precipitation increases with increased TC intensity. Based on the different phase of diurnal cycle, convective TC clouds were divided into very cold deep convective clouds (IR BTs<208K) and cold high clouds (208K

  3. Electrochemical probing of high-level radioactive waste tanks containing washed sludge and precipitates

    International Nuclear Information System (INIS)

    Bickford, D.F.; Congdon, J.W.; Oblath, S.B.

    1987-01-01

    At the U.S. Department of Energy's Savannah River Plant, corrosion of carbon steel storage tanks containing alkaline, high-level radioactive waste is controlled by specification of limits on waste composition and temperature. Processes for the preparation of waste for final disposal will result in waste with low corrosion inhibitor concentrations and, in some cases, high aromatic organic concentrations, neither of which are characteristic of previous operations. Laboratory tests, conducted to determine minimum corrosion inhibitor levels indicated pitting of carbon steel near the waterline for proposed storage conditions. In situ electrochemical measurements of full-scale radioactive process demonstrations have been conducted to assess the validity of laboratory tests. Probes included pH, Eh (potential relative to a standard hydrogen electrode), tank potential, and alloy coupons. In situ results are compared to those of the laboratory tests, with particular regard given to simulated solution composition

  4. Inclusive STEM High Schools Increase Opportunities for Underrepresented Students

    Science.gov (United States)

    Spillane, Nancy K.; Lynch, Sharon J.; Ford, Michael R.

    2016-01-01

    The authors report on a study of eight inclusive STEM high schools that are designed to increase the numbers of students in demographic groups underrepresented in STEM. As STEM schools, they have had broader and deeper STEM coursework (taken by all students) than required by their respective states and school districts; they also had outcome…

  5. Mechanical behavior of precipitation hardenable steels exposed to highly corrosive environment

    Science.gov (United States)

    Rosa, Ferdinand

    1994-01-01

    Unexpected occurrences of failures, due to stress corrosion cracking (SCC) of structural components, indicate a need for improved characterization of materials and more advanced analytical procedures for reliably predicting structures performance. Accordingly, the purpose of this study was to determine the stress corrosion susceptibility of 15 - 5 PH steel over a wide range of applied strain rates in a highly corrosive environment. The selected environment for this investigation was a 3.5 percent NaCl aqueous solution. The material selected for the study was 15 - 5 PH steel in the H 900 condition. The Slow Strain Rate technique was used to test the metallic specimens.

  6. Evaluation of the TMPA-3B42 precipitation product using a high-density rain gauge network over complex terrain in northeastern Iberia

    KAUST Repository

    El Kenawy, Ahmed M.

    2015-08-29

    The performance of the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA)-3B42 version 7 product is assessed over north-eastern Iberia, a region with considerable topographical gradients and complexity. Precipitation characteristics from a dense network of 656 rain gauges, spanning the period from 1998 to 2009, are used to evaluate TMPA-3B42 estimates on a daily scale. A set of accuracy estimators, including the relative bias, mean absolute error (MAE), root mean square error (RMSE) and Spearman coefficient was used to evaluate the results. The assessment indicates that TMPA-3B42 product is capable of describing the seasonal characteristics of the observed precipitation over most of the study domain. In particular, TMPA-3B42 precipitation agrees well with in situ measurements, with MAE less than 2.5mm.day-1, RMSE of 6.4mm.day-1 and Spearman correlation coefficients generally above 0.6. TMPA-3B42 provides improved accuracies in winter and summer, whereas it performs much worse in spring and autumn. Spatially, the retrieval errors show a consistent trend, with a general overestimation in regions of low altitude and underestimation in regions of heterogeneous terrain. TMPA-3B42 generally performs well over inland areas, while showing less skill in the coastal regions. A set of skill metrics, including a false alarm ratio [FAR], frequency bias index [FBI], the probability of detection [POD] and threat score [TS], is also used to evaluate TMPA performance under different precipitation thresholds (1, 5, 10, 25 and 50mm.day-1). The results suggest that TMPA-3B42 retrievals perform well in specifying moderate rain events (5-25mm.day-1), but show noticeably less skill in producing both light (<1mm.day-1) and heavy rainfall thresholds (more than 50mm.day-1). Given the complexity of the terrain and the associated high spatial variability of precipitation in north-eastern Iberia, the results reveal that TMPA-3B42 data provide an

  7. Evaluation of the TMPA-3B42 precipitation product using a high-density rain gauge network over complex terrain in northeastern Iberia

    KAUST Repository

    El Kenawy, Ahmed M.; Lopez-Moreno, Juan I.; McCabe, Matthew; Vicente-Serrano, Sergio M.

    2015-01-01

    The performance of the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA)-3B42 version 7 product is assessed over north-eastern Iberia, a region with considerable topographical gradients and complexity. Precipitation characteristics from a dense network of 656 rain gauges, spanning the period from 1998 to 2009, are used to evaluate TMPA-3B42 estimates on a daily scale. A set of accuracy estimators, including the relative bias, mean absolute error (MAE), root mean square error (RMSE) and Spearman coefficient was used to evaluate the results. The assessment indicates that TMPA-3B42 product is capable of describing the seasonal characteristics of the observed precipitation over most of the study domain. In particular, TMPA-3B42 precipitation agrees well with in situ measurements, with MAE less than 2.5mm.day-1, RMSE of 6.4mm.day-1 and Spearman correlation coefficients generally above 0.6. TMPA-3B42 provides improved accuracies in winter and summer, whereas it performs much worse in spring and autumn. Spatially, the retrieval errors show a consistent trend, with a general overestimation in regions of low altitude and underestimation in regions of heterogeneous terrain. TMPA-3B42 generally performs well over inland areas, while showing less skill in the coastal regions. A set of skill metrics, including a false alarm ratio [FAR], frequency bias index [FBI], the probability of detection [POD] and threat score [TS], is also used to evaluate TMPA performance under different precipitation thresholds (1, 5, 10, 25 and 50mm.day-1). The results suggest that TMPA-3B42 retrievals perform well in specifying moderate rain events (5-25mm.day-1), but show noticeably less skill in producing both light (<1mm.day-1) and heavy rainfall thresholds (more than 50mm.day-1). Given the complexity of the terrain and the associated high spatial variability of precipitation in north-eastern Iberia, the results reveal that TMPA-3B42 data provide an

  8. Numerical simulations of significant orographic precipitation in Madeira island

    Science.gov (United States)

    Couto, Flavio Tiago; Ducrocq, Véronique; Salgado, Rui; Costa, Maria João

    2016-03-01

    High-resolution simulations of high precipitation events with the MESO-NH model are presented, and also used to verify that increasing horizontal resolution in zones of complex orography, such as in Madeira island, improve the simulation of the spatial distribution and total precipitation. The simulations succeeded in reproducing the general structure of the cloudy systems over the ocean in the four periods considered of significant accumulated precipitation. The accumulated precipitation over the Madeira was better represented with the 0.5 km horizontal resolution and occurred under four distinct synoptic situations. Different spatial patterns of the rainfall distribution over the Madeira have been identified.

  9. Precipitation strengthened high strength, high conductivity Cu-Cr-Nb alloys produced by chill block melt spinning. Final Report Ph.D. Thesis

    Science.gov (United States)

    Ellis, David L.; Michal, Gary M.

    1989-01-01

    A series of Cu-based alloys containing 2 to 10 a/o Cr and 1 to 5 a/o Nb were produced by chill block melt spinning (CBMS). The melt spun ribbons were consolidated and hot rolled to sheet to produce a supersaturated Cu-Cr-Nb solid solution from which the high melting point intermetallic compound Cr2Nb could be precipitated to strengthen the Cu matrix. The results show that the materials possess electrical conductivities in excess of 90 percent that of pure Cu at 200 C and above. The strengths of the Cu-Cr-Nb alloys were much greater than Cu, Cu-0.6 Cr, NARloy-A, and NARloy-Z in the as-melt spun condition. The strengths of the consolidated materials were less than Cu-Cr and Cu-Cr-Zr below 500 C and 600 C respectively, but were significantly better above these temperatures. The strengths of the consolidated materials were greater than NARloy-Z, at all temperatures. The GLIDCOP possessed similar strength levels up to 750 C when the strength of the Cu-Cr-Nb alloys begins to degrade. The long term stability of the Cu-Cr-Nb alloys was measured by the microhardness of aged samples and the growth of precipitates. The microhardness measurements indicate that the alloys overage rapidly, but do not suffer much loss in strength between 10 and 100 hours which confirms the results of the electrical resistivity measurements taken during the aging of the alloys at 500 C. The loss in strength from peak strength levels is significant, but the strength remains exceptionally good. Transmission electron microscopy (TEM) of the as-melt spun samples revealed that Cr2Nb precipitates formed in the liquid Cu during the chill block melt spinning, indicating a very strong driving force for the formation of the precipitates. The TEM of the aged and consolidated materials indicates that the precipitates coarsen considerably, but remain in the submicron range.

  10. Comparison of past and future Mediterranean high and low extremes of precipitation and river flow projected using different statistical downscaling methods

    Directory of Open Access Journals (Sweden)

    P. Quintana-Seguí

    2011-05-01

    Full Text Available The extremes of precipitation and river flow obtained using three different statistical downscaling methods applied to the same regional climate simulation have been compared. The methods compared are the anomaly method, quantile mapping and a weather typing. The hydrological model used in the study is distributed and it is applied to the Mediterranean basins of France. The study shows that both quantile mapping and weather typing methods are able to reproduce the high and low precipitation extremes in the region of interest. The study also shows that when the hydrological model is forced with these downscaled data, there are important differences in the outputs. This shows that the model amplifies the differences and that the downscaling of other atmospheric variables might be very relevant when simulating river discharges. In terms of river flow, the method of the anomalies, which is very simple, performs better than expected. The methods produce qualitatively similar future scenarios of the extremes of river flow. However, quantitatively, there are still significant differences between them for each individual gauging station. According to these scenarios, it is expected that in the middle of the 21st century (2035–2064, the monthly low flows will have diminished almost everywhere in the region of our study by as much as 20 %. Regarding high flows, there will be important increases in the area of the Cévennes, which is already seriously affected by flash-floods. For some gauging stations in this area, the frequency of what was a 10-yr return flood at the end of the 20th century is expected to increase, with such return floods then occurring every two years in the middle of the 21st century. Similarly, the 10-yr return floods at that time are expected to carry 100 % more water than the 10-yr return floods experienced at the end of the 20th century. In the northern part of the Rhône basin, these extremes will be reduced.

  11. High resolution transmission electron microscopy study on the development of nanostructured precipitates in Al-Cu obtained by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Villalba, L.S., E-mail: luzgomez@geo.ucm.es [Materials Science and Engineering Department, Universidad Carlos III de Madrid, Leganes, Madrid (Spain); Instituto de Geociencias-(CSIC-UCM), Madrid (Spain); Delgado, M.L.; Ruiz-Navas, E.M. [Materials Science and Engineering Department, Universidad Carlos III de Madrid, Leganes, Madrid (Spain)

    2012-01-16

    Highlights: Black-Right-Pointing-Pointer Development of defect structures and nanoprecipitates after 10 h of mechanical alloying in Al-Cu system. Black-Right-Pointing-Pointer Defects act as nucleation sites of the {epsilon}Al{sub 2}Cu{sub 3} phase. Black-Right-Pointing-Pointer Incoherent and semicoherent precipitates are identified by TEM-HRTEM. Black-Right-Pointing-Pointer Moire patterns are associated to the {epsilon}Al{sub 2}Cu{sub 3} phase. - Abstract: Aluminum alloy 2014 is used to obtain nanostructured powders via mechanical alloying. The evolution of the diffusion processes is observed by the development of defect structures and nanoprecipitates after 10 h of milling. The characterization includes analytical and high resolution transmission electron microscopy. Dislocations associated with different Al/Cu ratio affect the material. These defects act as nucleation sites where precipitates of the {epsilon}Al{sub 2}Cu{sub 3} hexagonal phase have been identified. Moire fringes show the interference of {l_brace}1 1 1{r_brace}{sub Al} with {l_brace}10{sup -}10{r_brace}{sub {epsilon}Al{sub 2Cu{sub 3}}} glide planes and locally small shifts of 1/3{l_brace}1 1 1{r_brace}{sub Al} and 1/3{l_brace}10{sup -}10{r_brace}{sub {epsilon}Al{sub 2Cu{sub 3}}}. Changes in the Al/Cu ratio lead to the formation of other solid solutions identified in the Cu rich area and could correspond to transition phases.

  12. High resolution modelling of the extreme precipitation event over Algiers in November 2001

    Directory of Open Access Journals (Sweden)

    S. A. Moore

    2005-01-01

    Full Text Available Between 18:00UTC on Friday 9th November and 12:00UTC on Saturday 10th November 2001 260mm of rainfall was recorded at Bouzareah, compared to the November average of just 96mm. This extreme rainfall resulted in landslides and flooding, causing immense damage to the Bab-el-Oued district of Algiers and affected the lives of more than 2000 people. In this paper, key results from a modelling study of this event using the UK Met Office Unified Model at global (60km, regional (20km and national (4km horizontal resolutions are described. In general, it is found that the event could be well forecast with increases in resolution leading to better predictions of both the distribution and intensity of the rainfall. The role of the local orography and latent heating are also discussed.

  13. A novel electrostatic precipitator

    International Nuclear Information System (INIS)

    Tang, Minkang; Wang, Liqian; Lin, Zhigui

    2013-01-01

    ESP (Electrostatic Precipitation) has been widely used in the mining, building materials, metallurgy and power industries. Dust particles or other harmful particles from the airstream can be precipitated by ESP with great collecting efficiency. Because of its' large size, high cost and energy consumption, the scope of application of ESP has been limited to a certain extent. By means of the theory of electrostatics and fluid dynamics, a corona assembly with a self-cleaning function and a threshold voltage automatic tracking technology has been developed and used in ESP. It is indicated that compared with conventional ESP, the electric field length has been reduced to 1/10 of the original, the current density on the collecting electrode increased 3-5 times at the maximum, the approach speed of dust particles in the electric field towards the collecting electrode is 4 times that in conventional ESP and the electric field wind speed may be enhanced by 2-3 times the original. Under the premise of ESP having a high efficiency of dust removal, equipment volume may be actually reduced to 1/5 to 1/10 of the original volume and energy consumption may be reduced by more than 50%.

  14. Precipitation of Scale-Forming Species During Processing of High-Level Wastes

    International Nuclear Information System (INIS)

    Mattigod, Shas V.; Hobbs, David T.; Parker, Kent E.; McCready, David E.

    2004-01-01

    High-level wastes from fuel-reprocessing operations are being evaporated at the DOE Savannah River Site to concentrate the liquids to about 30 to 40% of their original volume before they are discharged into a holding tank. Recently, the operation of one of the evaporators became progressively more difficult due to more frequent buildup of limited solubility aluminosilicate compounds resulting in the shutdown of the evaporator. Our research objectives were to identify and characterize the chemistry and microstructure of these scale-forming species and to determine the kinetics of formation and transformation of these solids under evaporator conditions. The data we obtained from these tests showed that hydroxide concentration and process temperature are the key factors that control the rate of formation and transformation of the scale forming solids such as zeolite A, sodalite and cancrinite

  15. On the Mass Balance of Asphaltene Precipitation

    DEFF Research Database (Denmark)

    Andersen, Simon Ivar; Lira-Galeana, C.; Stenby, Erling Halfdan

    2001-01-01

    In the evaluation of experimental data as well as in calculation of phase equilibria the necessity of the application of mass balances is obvious. In the case of asphaltenes the colloidal nature of these compounds may highly affect the mass balance. In the present paper several experiments are pe......, and that the material in the second precipitation step was often of higher apparent molecular weight anti had an increased overall absorbance coefficient.......In the evaluation of experimental data as well as in calculation of phase equilibria the necessity of the application of mass balances is obvious. In the case of asphaltenes the colloidal nature of these compounds may highly affect the mass balance. In the present paper several experiments...... indicates that in temperature experiments as well as in solvent series experiments the precipitation of heavy asphaltenes affects the following precipitation of lighter asphaltenes. In both cases the mass balance using standard separation techniques cannot be closed, as less material is precipitated...

  16. Alternative Zr alloys with irradiation resistant precipitates for high burnup BWR application

    International Nuclear Information System (INIS)

    Garzarolli, F.; Ruhmann, H.; Van Swan, L.

    2002-01-01

    In the core of BWRs, the second-phase particles (SPP) of Zircaloy-2 and Zircaloy-4, the Zr(FeCr) 2 and the Zr 2 (FeNi) phase, release Fe and dissolve. The degree of dissolution depends on initial size and fluence. These SPP, however, are important for the corrosion behavior of Zircaloy. Zircaloy shows an increase of corrosion at a certain burnup, depending on the initial SPP size and fast neutron fluence. Only Zr alloys with irradiation resistant SPP avoid this type of increased corrosion completely. Two types of irradiation resistant materials were considered. One is a Zr-Sn-Fe alloy containing the Zr 3 Fe phase, which is irradiation resistant under BWR conditions. The other material is a Zr-Sn-Nb alloy containing the irradiation resistant β-Nb phase. In-BWR tests have shown that a Sn content of >0.8% is mandatory to minimize the nodular corrosion. Two prototypes of irradiation resistant alloys, Zr1.3Sn0.25-0.3 Fe and Zr1Sn2-3Nb, were irradiated in a BWR for 1372 days to a fast fluence of 9 x 10 21 n/cm 2 (E > 1 MeV). These irradiation tests showed that Zr1.3Sn0.25-0.3 Fe has a little lower resistance against nodular corrosion than optimized LTP (Low Temperature Process) Zircaloy-2/4 and revealed that Zr1Sn2-3Nb is superior to LTP Zircaloy-2/4 with respect to nodular and shadow corrosion resistance. The BWR corrosion resistance of Zr1Sn2-3Nb depends on heat treatment. The lowest corrosion was observed with material fabricated completely in the α-range, but also material manufactured in the lower (α+β)-range exhibits low corrosion. Material fabricated in the upper (α+β)-range showed a somewhat higher corrosion, a corrosion behavior similar to LTP Zircaloy-2/4. As far as final annealing is concerned, a long time annealing at 540 deg C is superior to a standard recrystallization treatment (e.g., at 580 deg C), which still leads to a corrosion behavior that is better than stress relieved Zr1Sn2-3Nb. Zr1Sn2-3Nb is resistant to shadow corrosion, when fabricated

  17. Studies on Pu(IV)/(III)-oxalate precipitation from nitric acid containing high concentration of calcium and fluoride ions

    International Nuclear Information System (INIS)

    Kalsi, P.K.; Pawar, S.M.; Ghadse, D.R.; Joshi, A.R.; Ramakrishna, V.V.; Vaidya, V.N.; Venugopal, V.

    2003-01-01

    Plutonium (IV)/(III) oxalate precipitation from nitric acid solution, containing large amount of calcium and fluoride ions was investigated. It was observed that direct precipitation of Pu (IV) oxalate from nitric acid containing large amount of calcium and fluoride ions did not give good decontamination of Pu from calcium and fluoride impurities. However, incorporation of hydroxide precipitation using ammonium hydroxide prior to Pu (IV) oxalate precipitation results into PuO 2 with much less calcium and fluoride impurities. Whereas, good decontamination from calcium and fluoride impurities could be obtained by employing Pu (III) oxalate precipitation directly from nitric acid containing large amount of calcium and fluoride ions. A method was also developed to recover Pu from the oxalate waste containing calcium and fluoride ions. (author)

  18. Evaluation of uncertainties in mean and extreme precipitation under climate change for northwestern Mediterranean watersheds from high-resolution Med and Euro-CORDEX ensembles

    Science.gov (United States)

    Colmet-Daage, Antoine; Sanchez-Gomez, Emilia; Ricci, Sophie; Llovel, Cécile; Borrell Estupina, Valérie; Quintana-Seguí, Pere; Llasat, Maria Carmen; Servat, Eric

    2018-01-01

    The climate change impact on mean and extreme precipitation events in the northern Mediterranean region is assessed using high-resolution EuroCORDEX and MedCORDEX simulations. The focus is made on three regions, Lez and Aude located in France, and Muga located in northeastern Spain, and eight pairs of global and regional climate models are analyzed with respect to the SAFRAN product. First the model skills are evaluated in terms of bias for the precipitation annual cycle over historical period. Then future changes in extreme precipitation, under two emission scenarios, are estimated through the computation of past/future change coefficients of quantile-ranked model precipitation outputs. Over the 1981-2010 period, the cumulative precipitation is overestimated for most models over the mountainous regions and underestimated over the coastal regions in autumn and higher-order quantile. The ensemble mean and the spread for future period remain unchanged under RCP4.5 scenario and decrease under RCP8.5 scenario. Extreme precipitation events are intensified over the three catchments with a smaller ensemble spread under RCP8.5 revealing more evident changes, especially in the later part of the 21st century.

  19. Highly Efficient Interception and Precipitation of Uranium(VI) from Aqueous Solution by Iron-Electrocoagulation Combined with Cooperative Chelation by Organic Ligands.

    Science.gov (United States)

    Li, Peng; Zhun, Bao; Wang, Xuegang; Liao, PingPing; Wang, Guanghui; Wang, Lizhang; Guo, Yadan; Zhang, Weimin

    2017-12-19

    A new strategy combining iron-electrocoagulation and organic ligands (OGLs) cooperative chelation was proposed to screen and precipitate low concentrations (0-18.52 μmol/L) of uranium contaminant in aqueous solution. We hypothesized that OGLs with amino, hydroxyl, and carboxyl groups hydrophobically/hydrophilically would realize precuring of uranyl ion at pH electrocoagulation would achieve faster and more efficient uranium precipitation. Experimentally, the strategy demonstrated highly efficient uranium(VI) precipitation efficiency, especially with hydrophilic macromolecular OGLs. The uranium removal efficiency at optimized experimental condition reached 99.65%. The decrease of zeta potential and the lattice enwrapping between U-OGLs chelates and flocculation precursor were ascribed to the enhanced uranium precipitation activity. Uranium was precipitated as oxides of U(VI) or higher valences that were easily captured in aggregated micelles under low operation current potential. The actual uranium tailing wastewater was treated, and a satisfied uranium removal efficiency of 99.02% was discovered. After elution of the precipitated flocs, a concentrated uranium solution (up to 106.52 μmol/L) with very few other metallic impurities was obtained. Therefore, the proposed strategy could remove uranium and concentrate it concurrently. This work could provide new insights into the purification and recovery of uranium from aqueous solutions in a cost-effective and environmentally friendly process.

  20. High Dietary Fat Selectively Increases Catalase Expression within Cardiac Mitochondria*

    Science.gov (United States)

    Rindler, Paul M.; Plafker, Scott M.; Szweda, Luke I.; Kinter, Michael

    2013-01-01

    Obesity is a predictor of diabetes and cardiovascular disease. One consequence of obesity is dyslipidemia characterized by high blood triglycerides. It has been proposed that oxidative stress, driven by utilization of lipids for energy, contributes to these diseases. The effects of oxidative stress are mitigated by an endogenous antioxidant enzyme network, but little is known about its response to high fat utilization. Our experiments used a multiplexed quantitative proteomics method to measure antioxidant enzyme expression in heart tissue in a mouse model of diet-induced obesity. This experiment showed a rapid and specific up-regulation of catalase protein, with subsequent assays showing increases in activity and mRNA. Catalase, traditionally considered a peroxisomal protein, was found to be present in cardiac mitochondria and significantly increased in content and activity during high fat feeding. These data, coupled with the fact that fatty acid oxidation enhances mitochondrial H2O2 production, suggest that a localized catalase increase is needed to consume excessive mitochondrial H2O2 produced by increased fat metabolism. To determine whether the catalase-specific response is a common feature of physiological conditions that increase blood triglycerides and fatty acid oxidation, we measured changes in antioxidant expression in fasted versus fed mice. Indeed, a similar specific catalase increase was observed in mice fasted for 24 h. Our findings suggest a fundamental metabolic process in which catalase expression is regulated to prevent damage while preserving an H2O2-mediated sensing of diet composition that appropriately adjusts insulin sensitivity in the short term as needed to prioritize lipid metabolism for complete utilization. PMID:23204527

  1. Combined High Spectral Resolution Lidar and Millimeter Wavelength Radar Measurement of Ice Crystal Precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Eloranta, Edwin [Univ. of Wisconsin, Madison, WI (United States)

    2016-10-28

    The goal of this research has been to improve measurements of snowfall using a combination of millimeter-wavelength radar and High Spectral Resolution Lidar (HSRL) Observations. Snowflakes are large compared to the 532nm HSRL wavelength and small compared to the 3.2 and 8.6 mm wavelength radars used in this study. This places the particles in the optical scattering regime of the HSRL, where extinction cross-section is proportional to the projected area of the particles, and in the Rayleigh regime for the radar, where the backscatter cross-section is proportional to the mass-squared of the particles. Forming a ratio of the radar measured cross-section to the HSRL measured cross section eliminates any dependence on the number of scattering particles, yielding a quantity proportional to the average mass-squared of the snowflakes over the average area of the flakes. Using simultaneous radar measurements of particle fall velocities, which are dependent particle mass and cross-sectional area it is possible to derive the average mass of the snow flakes, and with the radar measured fall velocities compute the snowfall rate. Since this retrieval requires the optical extinction cross-section we began by considering errors this quantity. The HSRL is particularly good at measuring the backscatter cross-section. In previous studies of snowfall in the high Arctic were able to estimate the extinction cross-section directly as a fixed ratio to the backscatter cross-section. Measurements acquired in the STORMVEX experiment in Colorado showed that this approach was not valid in mid-latitude snowfalls and that direct measurement of the extinction cross-section is required. Attempts to measure the extinction directly uncovered shortcomings in thermal regulation and mechanical stability of the newly deployed DOE HSRL systems. These problems were largely mitigated by modifications installed in both of the DOE systems. We also investigated other sources of error in the HSRL direct

  2. Precipitates in irradiated Zircaloy

    International Nuclear Information System (INIS)

    Chung, H.M.

    1985-10-01

    Precipitates in high-burnup (>20 MWd/kg U) Zircaloy spent-fuel cladding discharged from commercial boiling- and pressurized-water reactors have been characterized by TEM-HVEM. Three classes of primary precipitates were observed in the irradiated Zircaloys: Zr 3 O (2 to 6 nm), cubic-ZrO 2 (greater than or equal to 10 nm), and delta-hydride (35 to 100 nm). The former two precipitations appears to be irradiation induced in nature. Zr(Fe/sub x/Cr/sub 1-x/) 2 and Zr 2 (Fe/sub x/Ni/sub 1-x/) intermetallics, which are the primary precipitates in unirradiated Zircaloys, were largely dissolved after the high burnup. It seems, therefore, that the influence of the size and distribution of the intermetallics on the corrosion behavior may be quite different for the irradiated Zircaloys

  3. The effect of σ-phase precipitation at 800°C on the corrosion resistance in sea-water of a high alloyed duplex stainless steel

    NARCIS (Netherlands)

    Wilms, M.E.; Gadgil, V.J.; Krougman, J.M.; Ijsseling, F.P.

    1994-01-01

    Super-duplex stainless steels are recently developed high alloyed stainless steels that combine good mechanical properties with excellent corrosion resistance. Because of a high content of chromium and molybdenum, these alloys are susceptible to σ-phase precipitation during short exposure to

  4. Climatology and Interannual Variability of Quasi-Global Intense Precipitation Using Satellite Observations

    Science.gov (United States)

    Ricko, Martina; Adler, Robert F.; Huffman, George J.

    2016-01-01

    Climatology and variations of recent mean and intense precipitation over a near-global (50 deg. S 50 deg. N) domain on a monthly and annual time scale are analyzed. Data used to derive daily precipitation to examine the effects of spatial and temporal coverage of intense precipitation are from the current Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) 3B42 version 7 precipitation product, with high spatial and temporal resolution during 1998 - 2013. Intense precipitation is defined by several different parameters, such as a 95th percentile threshold of daily precipitation, a mean precipitation that exceeds that percentile, or a fixed threshold of daily precipitation value [e.g., 25 and 50 mm day(exp -1)]. All parameters are used to identify the main characteristics of spatial and temporal variation of intense precipitation. High correlations between examined parameters are observed, especially between climatological monthly mean precipitation and intense precipitation, over both tropical land and ocean. Among the various parameters examined, the one best characterizing intense rainfall is a fraction of daily precipitation Great than or equal to 25 mm day(exp. -1), defined as a ratio between the intense precipitation above the used threshold and mean precipitation. Regions that experience an increase in mean precipitation likely experience a similar increase in intense precipitation, especially during the El Nino Southern Oscillation (ENSO) events. Improved knowledge of this intense precipitation regime and its strong connection to mean precipitation given by the fraction parameter can be used for monitoring of intense rainfall and its intensity on a global to regional scale.

  5. Using Extreme Tropical Precipitation Statistics to Constrain Future Climate States

    Science.gov (United States)

    Igel, M.; Biello, J. A.

    2017-12-01

    Tropical precipitation is characterized by a rapid growth in mean intensity as the column humidity increases. This behavior is examined in both a cloud resolving model and with high-resolution observations of precipitation and column humidity from CloudSat and AIRS, respectively. The model and the observations exhibit remarkable consistency and suggest a new paradigm for extreme precipitation. We show that the total precipitation can be decomposed into a product of contributions from a mean intensity, a probability of precipitation, and a global PDF of column humidity values. We use the modeling and observational results to suggest simple, analytic forms for each of these functions. The analytic representations are then used to construct a simple expression for the global accumulated precipitation as a function of the parameters of each of the component functions. As the climate warms, extreme precipitation intensity and global precipitation are expected to increase, though at different rates. When these predictions are incorporated into the new analytic expression for total precipitation, predictions for changes due to global warming to the probability of precipitation and the PDF of column humidity can be made. We show that strong constraints can be imposed on the future shape of the PDF of column humidity but that only weak constraints can be set on the probability of precipitation. These are largely imposed by the intensification of extreme precipitation. This result suggests that understanding precisely how extreme precipitation responds to climate warming is critical to predicting other impactful properties of global hydrology. The new framework can also be used to confirm and discount existing theories for shifting precipitation.

  6. Comparison of direct and precipitation methods for the estimation of ...

    African Journals Online (AJOL)

    Background: There is increase in use of direct assays for analysis of high and low density lipoprotein cholesterol by clinical laboratories despite differences in performance characteristics with conventional precipitation methods. Calculation of low density lipoprotein cholesterol in precipitation methods is based on total ...

  7. Precipitation Matters

    Science.gov (United States)

    McDuffie, Thomas

    2007-01-01

    Although weather, including its role in the water cycle, is included in most elementary science programs, any further examination of raindrops and snowflakes is rare. Together rain and snow make up most of the precipitation that replenishes Earth's life-sustaining fresh water supply. When viewed individually, raindrops and snowflakes are quite…

  8. Strength and rupture-life transitions caused by secondary carbide precipitation in HT-9 during high-temperature low-rate mechanical testing

    International Nuclear Information System (INIS)

    DiMelfi, R.J.; Gruber, E.E.; Kramer, J.M.; Hughes, T.H.

    1992-01-01

    The martensitic-ferritic alloy HT-9 is slated for long-term use as a fuel-cladding material in the Integral Fast Reactor. Analysis of published high-temperature mechanical property data suggests that secondary carbide precipitation would occur during service life causing substantial strengthening of the as-heat-treated material. Aspects of the kinetics of this precipitation process are extracted from calculations of the back stress necessary to produce the observed strengthening effect under various creep loading conditions. The resulting Arrhenius factor is shown to agree quantitatively with shifts to higher strength of crept material in reference to the intrinsic strength of HT-9. The results of very low constant strain-rate high-temperature tensile tests on as-heat-treated HT-9 that focus on the transition in strength with precipitation will be presented and related to rupture-life

  9. Analysis of grain boundaries, twin boundaries, and Te precipitates in CdZnTe grown by high-pressure Bridgeman method

    International Nuclear Information System (INIS)

    Heffelfinger, J.R.; Medlin, D.L.; James, R.B.

    1998-03-01

    Grain boundaries and twin boundaries in commercial Cd 1-x Zn x Te, which is prepared by a high pressure Bridgeman technique, have been investigated with transmission electron microscopy, scanning electron microscopy, infrared light microscopy and visible light microscopy. Boundaries inside these materials were found to be decorated with Te precipitates. The shape and local density of the precipitates were found to depend on the particular boundary. For precipitates that decorate grain boundaries, their microstructure was found to consist of a single, saucer shaped grain of hexagonal Te (space group P3 1 21). Analysis of a Te precipitate precipitates by selected area diffraction revealed the Te to be aligned with the surrounding Cd 1-x Zn x Te grains. This alignment was found to match the (111) Cd 1-x Z x Te planes with the (1 bar 101) planes of hexagonal Te. Crystallographic alignments between the Cd 1-x Zn x Te grains were also observed for a high angle grain boundary. The structure of the grain boundaries and the Te/Cd 1-x Zn x Te interface are discussed

  10. High selection pressure promotes increase in cumulative adaptive culture.

    Directory of Open Access Journals (Sweden)

    Carolin Vegvari

    Full Text Available The evolution of cumulative adaptive culture has received widespread interest in recent years, especially the factors promoting its occurrence. Current evolutionary models suggest that an increase in population size may lead to an increase in cultural complexity via a higher rate of cultural transmission and innovation. However, relatively little attention has been paid to the role of natural selection in the evolution of cultural complexity. Here we use an agent-based simulation model to demonstrate that high selection pressure in the form of resource pressure promotes the accumulation of adaptive culture in spite of small population sizes and high innovation costs. We argue that the interaction of demography and selection is important, and that neither can be considered in isolation. We predict that an increase in cultural complexity is most likely to occur under conditions of population pressure relative to resource availability. Our model may help to explain why culture change can occur without major environmental change. We suggest that understanding the interaction between shifting selective pressures and demography is essential for explaining the evolution of cultural complexity.

  11. Detection of the relationship between peak temperature and extreme precipitation

    Science.gov (United States)

    Yu, Y.; Liu, J.; Zhiyong, Y.

    2017-12-01

    Under the background of climate change and human activities, the characteristics and pattern of precipitation have changed significantly in many regions. As the political and cultural center of China, the structure and character of precipitation in Jingjinji District has varied dramatically in recent years. In this paper, the daily precipitation data throughout the period 1960-2013 are selected for analyzing the spatial-temporal variability of precipitation. The results indicate that the frequency and intensity of precipitation presents an increasing trend. Based on the precipitation data, the maximum, minimum and mean precipitation in different temporal and spatial scales is calculated respectively. The temporal and spatial variation of temperature is obtained by using statistical methods. The relationship between temperature and precipitation in different range is analyzed. The curve relates daily precipitation extremes with local temperatures has a peak structure, increasing at the low-medium range of temperature variations but decreasing at high temperatures. The relationship between extreme precipitation is stronger in downtown than that in suburbs.

  12. The Formation of High-Coercivity, Oriented, Nanophase Cobalt Precipitates in Al2O3 single cyrstals by ion implantation

    International Nuclear Information System (INIS)

    Honda, S.; Modine, F.A.; Haynes, T.E.; Meldrum, A.; Budai, J.D.; SOng, K.J.; Thompson, J.R.; Boatner, L.A.

    1999-01-01

    Ion-implantation and thermal-processing methods have been used to form nanophase magnetic precipitates of metallic cobalt that are embedded in the near-surface region of single crystals of Al 2 O 3 . The Co precipitates are isolated, single-crystal particles that are crystallographically oriented with respect to the host Al 2 O 3 lattice. Embedded nanophase Co precipitates were formed by the implantation of Co+ at an energy of 140 keV and a dose of 8 x l0 16 ions/cm 2 followed by annealing in a reducing atmosphere. The implanted/annealed Co depth profile, particle size distributions and shapes, and the orientational relationship between the nanophase precipitates and the host crystal lattice were determined using RBS/channeling, transmission electron microscopy, and x-ray diffraction

  13. Probability Distribution and Projected Trends of Daily Precipitation in China

    Institute of Scientific and Technical Information of China (English)

    CAO; Li-Ge; ZHONG; Jun; SU; Bu-Da; ZHAI; Jian-Qing; Macro; GEMMER

    2013-01-01

    Based on observed daily precipitation data of 540 stations and 3,839 gridded data from the high-resolution regional climate model COSMO-Climate Limited-area Modeling(CCLM)for 1961–2000,the simulation ability of CCLM on daily precipitation in China is examined,and the variation of daily precipitation distribution pattern is revealed.By applying the probability distribution and extreme value theory to the projected daily precipitation(2011–2050)under SRES A1B scenario with CCLM,trends of daily precipitation series and daily precipitation extremes are analyzed.Results show that except for the western Qinghai-Tibetan Plateau and South China,distribution patterns of the kurtosis and skewness calculated from the simulated and observed series are consistent with each other;their spatial correlation coefcients are above 0.75.The CCLM can well capture the distribution characteristics of daily precipitation over China.It is projected that in some parts of the Jianghuai region,central-eastern Northeast China and Inner Mongolia,the kurtosis and skewness will increase significantly,and precipitation extremes will increase during 2011–2050.The projected increase of maximum daily rainfall and longest non-precipitation period during flood season in the aforementioned regions,also show increasing trends of droughts and floods in the next 40 years.

  14. Precipitation-productivity Relation in Grassland in Northern China: Investigations at Multiple Spatiotemporal Scales

    Science.gov (United States)

    Hu, Z.

    2017-12-01

    Climate change is predicted to cause dramatic variability in precipitation regime, not only in terms of change in annual precipitation amount, but also in precipitation seasonal distribution and precipitation event characteristics (high frenquency extrem precipitation, larger but fewer precipitation events), which combined to influence productivity of grassland in arid and semiarid regions. In this study, combining remote sensing products with in-situ measurements of aboveground net primary productivity (ANPP) and gross primary productivity (GPP) data from eddy covariance system in grassland of northern China, we quantified the effects of spatio-temporal vairation in precipitation on productivity from local sites to region scale. We found that, for an individual precipitation event, the duration of GPP-response to the individual precipitation event and the maximum absolute GPP response induced by the individual precipitation event increased linearly with the size of precipitation events. Comparison of the productivity-precipitation relationships between multi-sites determined that the predominant characteristics of precipitation events (PEC) that affected GPP differed remarkably between the water-limited temperate steppe and the temperature-limited alpine meadow. The number of heavy precipitation events (>10 mm d-1) was the most important PEC to impact GPP in the temperate steppe through affecting soil moisture at different soil profiles, while precipitation interval was the factor that affected GPP most in the alpine meadow via its effects on temperature. At the region scale, shape of ANPP-precipitation relationship varies with distinct spatial scales, and besides annual precipitation, precipitation seasonal distribution also has comparable impacts on spatial variation in ANPP. Temporal variability in ANPP was lower at both the dry and wet end, and peaked at a precipitation of 243.1±3.5mm, which is the transition region between typical steppe and desert steppe

  15. Antisolvent Precipitation for the Synthesis of Monodisperse Mesoporous Niobium Oxide Spheres as Highly Effective Solid Acid Catalysts

    KAUST Repository

    Li, Cheng Chao; Dou, Jian; Chen, Luwei; Lin, Jianyi; Zeng, Hua Chun

    2012-01-01

    We have developed a low-cost reaction protocol to synthesize mesoporous Nb 2O 5-based solid acid catalysts with external shape control. In the synthesis, monodisperse glycolated niobium oxide spheres (GNOS) were prepared by means of a simple antisolvent precipitation approach and subsequently converted to mesoporous niobium oxide spheres (MNOS) with a large surface area of 312m 2g -1 by means of the hydrothermal treatment. The antisolvent acetone used to obtain GNOS was recovered through distillation at high purity. The obtained mesoporous MNOS were functionalized further with sulfate anions at different temperatures or incorporated with tungstophosphoric acid to obtain recyclable solid acid catalysts. These MNOS-based catalysts showed excellent performance in a wide range of acid-catalyzed reactions, such as Friedel-Crafts alkylation, esterification, and hydrolysis of acetates. As they are monodisperse spheres with diameters in the submicrometer range, the catalysts can be easily separated and reused. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Antisolvent Precipitation for the Synthesis of Monodisperse Mesoporous Niobium Oxide Spheres as Highly Effective Solid Acid Catalysts

    KAUST Repository

    Li, Cheng Chao

    2012-03-20

    We have developed a low-cost reaction protocol to synthesize mesoporous Nb 2O 5-based solid acid catalysts with external shape control. In the synthesis, monodisperse glycolated niobium oxide spheres (GNOS) were prepared by means of a simple antisolvent precipitation approach and subsequently converted to mesoporous niobium oxide spheres (MNOS) with a large surface area of 312m 2g -1 by means of the hydrothermal treatment. The antisolvent acetone used to obtain GNOS was recovered through distillation at high purity. The obtained mesoporous MNOS were functionalized further with sulfate anions at different temperatures or incorporated with tungstophosphoric acid to obtain recyclable solid acid catalysts. These MNOS-based catalysts showed excellent performance in a wide range of acid-catalyzed reactions, such as Friedel-Crafts alkylation, esterification, and hydrolysis of acetates. As they are monodisperse spheres with diameters in the submicrometer range, the catalysts can be easily separated and reused. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Precipitation reactions caused by nitrogen uptake during service at high temperatures of a niobium stabilised austenitic stainless steel

    International Nuclear Information System (INIS)

    Erneman, J.; Schwind, M.; Liu, P.; Nilsson, J.-O.; Andren, H.-O.; Aagren, J.

    2004-01-01

    Precipitation phenomena in type 347 austenitic stainless steels have been investigated after long-term heat treatment and creep in air at 700 and 800 deg. C. Nitrogen uptake was observed during long-term creep testing at 800 deg. C. No such effect was observed at 700 deg. C although times up to about 70,000 h were used. The major phases precipitated after long time exposure at 800 deg. C were primary Nb(C,N), Z-phase, Cr 2 N and M 23 C 6 , while primary Nb(C,N), secondary Nb(C,N) and σ-phase were the major phases at 700 deg. C. Z-phase precipitated in both intragranular and intergranular form at 800 deg. C. Large precipitates exhibiting a core/rim structure showed a rim of Z-phase surrounding undissolved primary Nb(C,N). The microstructural evolution during creep deformation in air at 800 deg. C was modelled thermodynamically. The model satisfactorily predicts nitrogen uptake and the essential features of the evolution of the microstructure with time. The precipitation sequence could be qualitatively described, although it was not possible to model the formation of all precipitates

  18. Improvement of high floods predictability in the Red River of the North basin using combined remote-sensed, gauge-based and assimilated precipitation data

    Science.gov (United States)

    Semenova, O.; Restrepo, P. J.

    2011-12-01

    The Red River of the North basin (USA) is considered to be under high risk of flood danger, having experienced serious flooding during the last few years. The region climate can be characterized as cold and, during winter, it exhibits continuous snowcover modified by wind redistribution. High-hazard runoff regularly occurs as a major spring snowmelt event resulting from the relatively rapid release of water from the snowpack on frozen soils. Although in summer/autumn most rainfall occurs from convective storms over small areas and does not generate dangerous floods, the pre-winter state of the soils may radically influence spring maximum flows. Large amount of artificial agricultural tiles and numerous small post-glacial depressions influencing the redistribution of runoff complicates the predictions of high floods. In such conditions any hydrological model would not be successful without proper precipitation input. In this study the simulation of runoff processes for two watersheds in the basin of the Red River of the North, USA, was undertaken using the Hydrograph model developed at the State Hydrological Institute (St. Petersburg, Russia). The Hydrograph is a robust process-based model, where the processes have a physical basis combined with some strategic conceptual simplifications that give it the ability to be applied in the conditions of low information availability. It accounts for the processes of frost and thaw of soils, snow redistribution and depression storage impacts. The assessment of the model parameters was conducted based on the characteristics of soil and vegetation cover. While performing the model runs, the parameters of depression storage and the parameters of different types of flow were manually calibrated to reproduce the observed flow. The model provided satisfactory simulation results in terms not only of river runoff but also variable sates of soil like moisture and temperature over a simulation period 2005 - 2010. For experimental runs

  19. Increased Cardiometabolic Risk and Worsening Hypoxemia at High Altitude.

    Science.gov (United States)

    Miele, Catherine H; Schwartz, Alan R; Gilman, Robert H; Pham, Luu; Wise, Robert A; Davila-Roman, Victor G; Jun, Jonathan C; Polotsky, Vsevolod Y; Miranda, J Jaime; Leon-Velarde, Fabiola; Checkley, William

    2016-06-01

    Miele, Catherine H., Alan R. Schwartz, Robert H. Gilman, Luu Pham, Robert A. Wise, Victor G. Davila-Roman, Jonathan C. Jun, Vsevolod Y. Polotsky, J. Jaime Miranda, Fabiola Leon-Velarde, and William Checkley. Increased cardiometabolic risk and worsening hypoxemia at high altitude. High Alt Med Biol. 17:93-100, 2016.-Metabolic syndrome, insulin resistance, diabetes, and dyslipidemia are associated with an increased risk of cardiovascular disease. While excessive erythrocytosis is associated with cardiovascular complications, it is unclear how worsening hypoxemia of any degree affects cardiometabolic risk factors in high-altitude populations. We studied the relationship between daytime resting oxyhemoglobin saturation and cardiometabolic risk factors in adult participants living in Puno, Peru (3825 m above sea level). We used multivariable logistic regression models to study the relationship between having a lower oxyhemoglobin saturation and markers of cardiometabolic risk. Nine hundred and fifty-four participants (mean age 55 years, 52% male) had information available on pulse oximetry and markers of cardiometabolic risk. Average oxyhemoglobin saturation was 90% (interquartile range 88%-92%) and 43 (4.5%) had excessive erythrocytosis. Older age, decreased height-adjusted lung function, and higher body mass index (BMI) were associated with having an oxyhemoglobin saturation ≤85%. When adjusting for age, sex, socioeconomic status, having excessive erythrocytosis, and site, we found that each 5% decrease in oxyhemoglobin saturation was associated with a higher adjusted odds of metabolic syndrome (OR = 1.35, 95% CI: 1.07-1.72, p 2 mass units (OR = 1.29, 95% CI: 1.00-1.67, p < 0.05), hemoglobin A1c ≥6.5% (OR = 1.66, 95% CI: 1.09-2.51, p < 0.04), and high sensitivity C-reactive protein (hs-CRP) ≥3 mg/L (OR = 1.46, 95% CI: 1.09-1.96, p < 0.01). In high-altitude populations in Puno, Peru, a higher BMI and lower pulmonary function were

  20. Development of precipitator of fluid film type

    International Nuclear Information System (INIS)

    Liu Yupu

    1987-01-01

    The precipitator of fluid film type is developed for the determination of fuel element cladding failure of water-cooled reactor. It integrates the scrubber, precipitator and detector. The jet of element cooling water automatically circulates carrier gas and the flow water film transfers precipitates onto the surface of centre electrode. Three different types are designed. On the special test loop, the uranium sample pellets of simulating cladding failure is measured. The sensitivity of precipitators, saturated precipitation voltage, incremental speed of signal, speed of driving out precipitates and the contents of the precipitates are determined. The test shows that the precipitators are highly sensitive, reliable, cheap and easy to operate

  1. Hydrogen trapping by VC precipitates and structural defects in a high strength Fe–Mn–C steel studied by small-angle neutron scattering

    International Nuclear Information System (INIS)

    Malard, B.; Remy, B.; Scott, C.; Deschamps, A.; Chêne, J.; Dieudonné, T.; Mathon, M.H.

    2012-01-01

    Highlights: ► SANS was used to study the interaction between H and a Fe–Mn–C steel containing V. ► No interaction between H and V in solid solution has been detected. ► A reversible interaction between H and structural defects has been measured. ► 5 ppm wt. of H can be trapped in the VC nanoprecipitates. - Abstract: The trapping of hydrogen by VC precipitates and structural defects in high strength Fe–Mn–C steel was studied by small angle neutron scattering. No interaction between H and V in solid solution has been detected but a significant interaction between H and structural defects introduced by plastic deformation has been measured. This last effect was reversible upon outgassing of the H. Moreover a significant interaction between H and VC precipitates has been measured; 5 ppm wt. of H could be trapped in the precipitates. This is consistent with the homogeneous trapping of H within the precipitates rather than at the precipitate/matrix interface.

  2. An Optimized Trichloroacetic Acid/Acetone Precipitation Method for Two-Dimensional Gel Electrophoresis Analysis of Qinchuan Cattle Longissimus Dorsi Muscle Containing High Proportion of Marbling.

    Science.gov (United States)

    Hao, Ruijie; Adoligbe, Camus; Jiang, Bijie; Zhao, Xianlin; Gui, Linsheng; Qu, Kaixing; Wu, Sen; Zan, Linsen

    2015-01-01

    Longissimus dorsi muscle (LD) proteomics provides a novel opportunity to reveal the molecular mechanism behind intramuscular fat deposition. Unfortunately, the vast amounts of lipids and nucleic acids in this tissue hampered LD proteomics analysis. Trichloroacetic acid (TCA)/acetone precipitation is a widely used method to remove contaminants from protein samples. However, the high speed centrifugation employed in this method produces hard precipitates, which restrict contaminant elimination and protein re-dissolution. To address the problem, the centrifugation precipitates were first grinded with a glass tissue grinder and then washed with 90% acetone (TCA/acetone-G-W) in the present study. According to our result, the treatment for solid precipitate facilitated non-protein contaminant removal and protein re-dissolution, ultimately improving two-dimensional gel electrophoresis (2-DE) analysis. Additionally, we also evaluated the effect of sample drying on 2-DE profile as well as protein yield. It was found that 30 min air-drying did not result in significant protein loss, but reduced horizontal streaking and smearing on 2-DE gel compared to 10 min. In summary, we developed an optimized TCA/acetone precipitation method for protein extraction of LD, in which the modifications improved the effectiveness of TCA/acetone method.

  3. High lung volume increases stress failure in pulmonary capillaries

    Science.gov (United States)

    Fu, Z.; Costello, M. L.; Tsukimoto, K.; Prediletto, R.; Elliott, A. R.; Mathieu-Costello, O.; West, J. B.

    1992-01-01

    We previously showed that when pulmonary capillaries in anesthetized rabbits are exposed to a transmural pressure (Ptm) of approximately 40 mmHg, stress failure of the walls occurs with disruption of the capillary endothelium, alveolar epithelium, or sometimes all layers. The present study was designed to test whether stress failure occurred more frequently at high than at low lung volumes for the same Ptm. Lungs of anesthetized rabbits were inflated to a transpulmonary pressure of 20 cmH2O, perfused with autologous blood at 32.5 or 2.5 cmH2O Ptm, and fixed by intravascular perfusion. Samples were examined by both transmission and scanning electron microscopy. The results were compared with those of a previous study in which the lung was inflated to a transpulmonary pressure of 5 cmH2O. There was a large increase in the frequency of stress failure of the capillary walls at the higher lung volume. For example, at 32.5 cmH2O Ptm, the number of endothelial breaks per millimeter cell lining was 7.1 +/- 2.2 at the high lung volume compared with 0.7 +/- 0.4 at the low lung volume. The corresponding values for epithelium were 8.5 +/- 1.6 and 0.9 +/- 0.6. Both differences were significant (P less than 0.05). At 52.5 cmH2O Ptm, the results for endothelium were 20.7 +/- 7.6 (high volume) and 7.1 +/- 2.1 (low volume), and the corresponding results for epithelium were 32.8 +/- 11.9 and 11.4 +/- 3.7. At 32.5 cmH2O Ptm, the thickness of the blood-gas barrier was greater at the higher lung volume, consistent with the development of more interstitial edema. Ballooning of the epithelium caused by accumulation of edema fluid between the epithelial cell and its basement membrane was seen at 32.5 and 52.5 cmH2O Ptm. At high lung volume, the breaks tended to be narrower and fewer were oriented perpendicular to the axis of the pulmonary capillaries than at low lung volumes. Transmission and scanning electron microscopy measurements agreed well. Our findings provide a physiological

  4. Stability of TaC precipitates in a Co-Re-based alloy being developed for ultra-high-temperature applications

    Czech Academy of Sciences Publication Activity Database

    Gilles, R.; Mukherji, D.; Karge, L.; Strunz, Pavel; Beran, Přemysl; Barbier, B.; Kriele, A.; Hofmann, M.; Eckerlebe, H.; Rösler, J.

    2016-01-01

    Roč. 49, č. 4 (2016), s. 1253-1265 ISSN 1600-5767 R&D Projects: GA ČR GB14-36566G Institutional support: RVO:61389005 Keywords : high-temperature alloys * precipitates * small-angle neutron scattering * phase transformation * X-ray diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.495, year: 2016

  5. Application of the Alternative Traditional and Selective Precipitation Routes for Recovery of High Grade Thorium Concentrates from Egyptian Crude Monazite Sand

    International Nuclear Information System (INIS)

    Helaly, O.S.

    2017-01-01

    Process flow sheet selection for thorium separation in relatively high grade concentrate from Egyptian crude monazite sand was carried out. Traditional selective leaching and precipitation routes were applied after sulfuric acid digestion upon Egyptian crude monazite for this purpose. The resultant hot grey sulfate paste from monazite digestion was firstly cooled to ambient temperature then leached by normal water into two successive stages. The first leach solution contained most of the thorium which represents about 88% of the present thorium and its concentration in the liquor reached 4.5 g Th/l. This liquor also contains most of the free acids and major of impurities especially iron (more than 6.3 g Fe/l). Different routes were tested to evaluate the suitable conditions that verify maximum recovery of thorium from such monazite sulfate solution and producing relatively high grade concentrate. Two different possible traditional and selective methods were involved, namely; thorium initial precipitation with rare earth elements as double sulfate or its precipitation as phosphate through acidity control at ph 1.1 which seems to be the simple, brief and convenient route to accomplish this purpose. Further separation and/or upgrading of thorium from these precipitates (after conversion to hydroxides or without) were conducted through re-dissolution in hydrochloric acid and re-precipitation with different selective reagents in the form of hydroxide, oxalate or fluoride was also included. The target was accomplished through thorium co-precipitation with light rare earth elements as double sulfate, followed by its recovery from this fraction, where a concentrate of grade 68.3% was produced

  6. Flotation separation of strontium via phosphate precipitation.

    Science.gov (United States)

    Thanh, Luong H V; Liu, J C

    2017-06-01

    Flotation separation of strontium (Sr) from wastewater via phosphate precipitation was investigated. While 37.33% of Sr precipitated at highly alkaline pH in the absence of PO 4 3- , it completely precipitated as Sr 3 (PO 4 ) 2 at a molar ratio ([PO 4 3- ]:[Sr 2+ ]) of 0.62 at a lower pH value. The presence of Ca 2+ hindered Sr precipitation, yet it could be overcome by increasing the PO 4 3- dose. Sodium dodecyl sulfate (SDS) was a better collector for dispersed air flotation of Sr 3 (PO 4 ) 2 than cetyl trimethyl ammonium bromide, or mixed collector systems of SDS and saponin. The highest separation efficiency of 97.5% was achieved at an SDS dose of 40 mg/L. The main mechanism in the precipitate flotation is adsorption of anionic SDS on the positively charged surface of colloidal Sr 3 (PO 4 ) 2 via electrostatic interaction. SDS enhanced the aggregation of Sr 3 (PO 4 ) 2 precipitates as the size increased from 1.65 to 28.0 μm, which was beneficial to separation as well.

  7. "Live High-Train High" increases hemoglobin mass in Olympic swimmers

    DEFF Research Database (Denmark)

    Bonne, Thomas Christian; Lundby, Carsten; Jørgensen, Susanne

    2014-01-01

    PURPOSE: This study tested whether 3-4 weeks of classical "Live High-Train High" (LHTH) altitude training increases swim-specific VO2max through increased hemoglobin mass (Hbmass). METHODS: Ten swimmers lived and trained for more than 3 weeks between 2,130 and 3,094 m of altitude, and a control...

  8. Winter precipitation effect in a mid-latitude temperature-limited environment: the case of common juniper at high elevation in the Alps

    International Nuclear Information System (INIS)

    Pellizzari, Elena; Pividori, Mario; Carrer, Marco

    2014-01-01

    Common juniper (Juniperus communis L.) is by far the most widespread conifer in the world. However, tree-ring research dealing with this species is still scarce, mainly due to the difficulty in crossdating associated with the irregular stem shape with strip-bark growth form in older individuals and the high number of missing and wedging rings. Given that many different species of the same genus have been successfully used in tree-ring investigations and proved to be reliable climate proxies, this study aims to (i) test the possibility to successfully apply dendrochronological techniques on common juniper growing above the treeline and (ii) verify the climate sensitivity of the species with special regard to winter precipitation, a climatic factor that generally does not affect tree-ring growth in all Alpine high-elevation tree species. Almost 90 samples have been collected in three sites in the central and eastern Alps, all between 2100 and 2400 m in elevation. Despite cross-dating difficulties, we were able to build a reliable chronology for each site, each spanning over 200 years. Climate-growth relationships computed over the last century highlight that juniper growth is mainly controlled by the amount of winter precipitation. The high variability of the climate-growth associations among sites, corresponds well to the low spatial dependence of this meteorological factor. Fairly long chronologies and the presence of a significant precipitation signal open up the possibility to reconstruct past winter precipitation. (letter)

  9. ACUTE PHASE PROTEIN INCREASE IN HIGH ALTITUDE MOUNTAINEERS

    Directory of Open Access Journals (Sweden)

    Tolga Saka

    Full Text Available ABSTRACT Introduction: Many middle-aged Turks go hiking in mountains to breathe some fresh air or to maintain fitness. Objective: This study investigated the effects of regular high altitude mountain climbing on the metabolic and hematological responses of mountaineers. Methods: Hematological and biochemical parameters were studied, as well as some hormonal values of 21 mountaineers and 16 healthy age-matched sedentary volunteers. Results: The neutrophil to lymphocyte ratio (NLR was significantly lower (p<0.04 in mountaineers compared with the sedentary group. Total protein (p<0.001 and albumin (p<0.001 were lower, while the levels of ferritin (p<0.04, creatine (p<0.03 and creatine phosphokinase (p<0.01 were higher in mountaineers. Other hematological and biochemical parameters, i.e., erythrocytes, leukocytes, hemoglobin and hematocrit, did not change significantly. Conclusion: Our results show that regular exposure to high altitude increased the serum levels of some acute phase proteins with anti-inflammatory properties.

  10. The Effect of Surface Preparation on the Precipitation of Sigma During High Temperature Exposure of S32205 Duplex Stainless Steel

    Science.gov (United States)

    Jepson, Mark A. E.; Rowlett, Matthew; Higginson, Rebecca L.

    2017-03-01

    Although the formation of sigma phase in duplex stainless steels is reasonably well documented, the effect of surface finish on its formation rate in surface regions has not been previously noted. The growth of the sigma phase precipitated in the subsurface region (to a maximum depth of 120 μm) has been quantified after heat treatment of S32205 duplex stainless steel at 1073 K (800 °C) and 1173 K (900 °C) after preparation to two surface finishes. Here, results are presented that show that there is a change in the rate of sigma phase formation in the surface region of the material, with a coarser surface finish leading to a greater depth of precipitation at a given time and temperature of heat treatment. The growth rate and morphology of the precipitated sigma has been examined and explored in conjunction with thermodynamic equilibrium phase calculations.

  11. Recovery of Am-Cm from high-activity waste concentrate by in-canyon-tank precipitation as oxalates

    International Nuclear Information System (INIS)

    Gray, L.W.; Burney, G.A.; Wilson, T.W.; McKibben, J.M.

    1980-01-01

    Savannah River Laboratory and Savannah River Plant have been separating actinides for more than 25 years. Work continues to upgrade processes and to initiate new processes. This report summarizes work on a precipitation process to separate kg amounts of Am and Cm from hundreds of kilograms of NaNO 3 and Al(NO 3 ) 3 . The developed process includes formic acid denitration of the Am-Cm bearing streams for acid adjustment; oxalate precipitation of the Am-Cm; and Mn +2 catalyzed oxidation of oxalate in both the decanted supernate and the precipitated actinides. The new process generates one fourth the radioactive waste as the solvent extraction process which it replaced, and produces a cleaner feed solution for downstream processing to separate the Am and Cm before conversion to their respective oxides

  12. High hydrogen loading of thin palladium wires through alkaline earth carbonates' precipitation on the cathodic surface - evidence of a new phase in the Pd-H system

    International Nuclear Information System (INIS)

    Celani, F.; Spallone, A.; Di Gioacchino, D.; Marini, P.; Di Stefano, V.; Nakamura, M.; Pace, S.; Vecchione, A.; Tripodi, P.

    2000-01-01

    A new protocol for the electrolytic loading of hydrogen (H) in thin palladium (Pd) wires has been developed. In order to increase the cathodic overvoltage, which is known to be the main parameter capable to enhance the electrolytic H loading of Pd, the catalytic action of the Pd surface versus H-H recombination has been strongly reduced by precipitation of a thin layer of alkaline-earth carbonates on the cathode. A set of electrolytes has been employed, containing small amounts of hydrochloric or sulfuric acid and strontium or calcium ions. The H loading has been continuously evaluated through ac measurements of the Pd wire resistance. Uncommonly low resistivity values, leading to an estimate of exceptionally high H loading, have been observed. Evidence of the existence of a new phase in the very high H content region of the Pd-H system has been inferred on the basis of the determination of the temperature coefficient of the electrical resistivity. Mainly for this purpose a thin layer of Hg was galvanically deposed on the cathodic surface, in order to prevent any H deloading during the measurements. The results have been fully reproduced in other 2 well equipped and experienced Laboratories (Italy, USA)

  13. Study on effect of precipitation conditions on the properties of ammonium diuranate

    International Nuclear Information System (INIS)

    Kraikaew, J.; Yacumpai, O.; Pruantonsai, P.

    1994-01-01

    This study was carried out in order to select the optimum conditions for ammonium diuranate (ADU) precipitation to obtain high density uranium dioxide. The data were collected for ADU precipitation reactor design. The precipitation temperature was controlled at 50 0 C. The stirrer speeds are 5.9 and 7.1 Hz. The properties namely : specific filtration resistance, initial settling rate and agglomerate size of ADU precipitates obtained at various pH were investigated. The results indicated that when the pH of precipitation increases, specific filtration resistance increases but ADU agglomerate size decreases and causing difficulty in filtration

  14. Stable Isotopic Variations in Precipitation in Southwest China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This study analyzes the relationships of stable isotopes in precipitation with temperature, air pressure and humidity at different altitudes, and the potential influencing mechanisms of control factors on the stable isotopes in precipitation in Southwest China. There appear marked negative correlations of the δ18O in precipitation with precipitation amount, vapor pressure and atmospheric precipitable water (PW)at the Mengzi, Simao and Tengchong stations on the synoptic timescale; the marked negative correlations between the δ18O in precipitation and the diurnal mean temperature at 400 hPa, 500 hPa, 700 hPa and 850hPa are different from the temperature effect in middle-high-latitude inland areas. In addition, the notable positive correlation between the δ18O in precipitation and the dew-point deficit △Td at different altitudes is found at the three stations. Precipitation is not the only factor generating an amount effect. Probably,the amount effect is related to the variations of atmospheric circulation and vapor origins. On the annual timescale, the annual precipitation amount weighted-mean δ18O displays negative correlations not only with annual precipitation but also with annual mean temperature at 500 hPa. It can be deduced that, in the years with an abnormally strong summer monsoon, more warm and wet air from low-latitude oceans is transported northward along the vapor channel located in Southwest China and generates abnormally strong rainfall on the way. Meanwhile, the abnormally strong condensation process will release more condensed latent heat in the atmosphere, and this will lead to a rise of atmospheric temperature during rainfall but a decline of δ18O in the precipitation. On the other hand, in the years with an abnormally weak summer monsoon, the precipitation and the atmospheric temperature during rainfalls decrease abnormally but the δ18O in precipitation increases.

  15. Increasing STEM Competence in Urban, High Poverty Elementary School Populations

    Directory of Open Access Journals (Sweden)

    Sueanne McKinney

    2017-10-01

    Full Text Available Enhancing STEM competence (e.g., interests, knowledge, skills, and dispositions among urban, high poverty, elementary school populations in the United States (U.S. is and remains a growing national concern, especially since Science, Technology, Engineering and Mathematics (STEM competence is and will continue to be a necessary requisite for gainful employment in the future, according to workforce development experts. In an attempt to address this gap, many urban elementary schools have begun to offer STEM-related programs to increase STEM learning at an early age. STEM competence (interest, knowledge, skills, and dispositions, however, remains low. This paper results in a matrix used to analyze children's fictional literary selections and a model that argues that elementary teachers, as the first point of contact with young students, can affect STEM competence. By adopting a more culturally responsive pedagogy that attends to the 21st Century Learning Skills and the Next Generation Science Standards, teachers can choose literature that serves to excite and reinforce STEM learning.

  16. High Level Waste (HLW) Processing Experience with Increased Waste Loading

    International Nuclear Information System (INIS)

    JANTZEN, CAROL

    2004-01-01

    The Defense Waste Processing Facility (DWPF) Engineering requested characterization of glass samples that were taken after the second melter had been operational for about 5 months. After the new melter had been installed, the waste loading had been increased to about 38 weight percentage after a new quasicrystalline liquidus model had been implemented. The DWPF had also switched from processing with refractory Frit 200 to a more fluid Frit 320. The samples were taken after DWPF observed very rapid buildup of deposits in the upper pour spout bore and on the pour spout insert while processing the high waste loading feedstock. These samples were evaluated using various analytical techniques to determine the cause of the crystallization. The pour stream sample was homogeneous, amorphous, and representative of the feed batch from which it was derived. Chemical analysis of the pour stream sample indicated that a waste loading of 38.5 weight per cent had been achieved. The data analysis indicated that surface crystallization, induced by temperature and oxygen fugacity gradients in the pour spout, caused surface crystallization to occur in the spout and on the insert at the higher waste loadings even though there was no crystallization in the pour stream

  17. Variations in High-density Precipitation under Climate Changes in the LMRB and Implications on Drinking Water Supply Security - Paper

    Science.gov (United States)

    A systematic temporal and spatial analysis is being conducted at the U.S. EPA on historical precipitation and stream flow over the continental U.S. and their relationships with Atlantic hurricanes and lower Mississippi river basin flooding. The objective is to decipher the period...

  18. Quantitative precipitation estimation based on high-resolution numerical weather prediction and data assimilation with WRF – a performance test

    Directory of Open Access Journals (Sweden)

    Hans-Stefan Bauer

    2015-04-01

    Full Text Available Quantitative precipitation estimation and forecasting (QPE and QPF are among the most challenging tasks in atmospheric sciences. In this work, QPE based on numerical modelling and data assimilation is investigated. Key components are the Weather Research and Forecasting (WRF model in combination with its 3D variational assimilation scheme, applied on the convection-permitting scale with sophisticated model physics over central Europe. The system is operated in a 1-hour rapid update cycle and processes a large set of in situ observations, data from French radar systems, the European GPS network and satellite sensors. Additionally, a free forecast driven by the ECMWF operational analysis is included as a reference run representing current operational precipitation forecasting. The verification is done both qualitatively and quantitatively by comparisons of reflectivity, accumulated precipitation fields and derived verification scores for a complex synoptic situation that developed on 26 and 27 September 2012. The investigation shows that even the downscaling from ECMWF represents the synoptic situation reasonably well. However, significant improvements are seen in the results of the WRF QPE setup, especially when the French radar data are assimilated. The frontal structure is more defined and the timing of the frontal movement is improved compared with observations. Even mesoscale band-like precipitation structures on the rear side of the cold front are reproduced, as seen by radar. The improvement in performance is also confirmed by a quantitative comparison of the 24-hourly accumulated precipitation over Germany. The mean correlation of the model simulations with observations improved from 0.2 in the downscaling experiment and 0.29 in the assimilation experiment without radar data to 0.56 in the WRF QPE experiment including the assimilation of French radar data.

  19. High-Frequency Neuromuscular Electrical Stimulation Increases Anabolic Signaling.

    Science.gov (United States)

    Mettler, Joni A; Magee, Dillon M; Doucet, Barbara M

    2018-03-16

    Neuromuscular electrical stimulation (NMES) is commonly used in rehabilitation settings to increase muscle mass and strength. However, the effects of NMES on muscle growth are not clear and no human studies have compared anabolic signaling between low-frequency (LF-) and high-frequency (HF-) NMES. The purpose of this study was to determine the skeletal muscle anabolic signaling response to an acute bout of LF- and HF-NMES. Eleven young healthy volunteers (6 men; 5 women) received an acute bout of LF- (20 Hz) and HF- (60 Hz) NMES. Muscle biopsies were obtained from the vastus lateralis muscle prior to the first NMES treatment and 30-mins following each NMES treatment. Phosphorylation of the following key anabolic signaling proteins was measured by Western blot and proteins are expressed as a ratio of phosphorylated to total: mammalian target of rapamycin (mTOR), p70-S6 kinase 1 (S6K1), and eukaryotic initiation factor 4E binding protein 1 (4E-BP1). Compared to Pre-NMES, phosphorylation of mTOR was upregulated 40.2% for LF-NMES (P = 0.018) and 68.4% for HF-NMES (P 0.05). There were no differences between treatment conditions for 4E-BP1 phosphorylation (P > 0.05). An acute bout of LF- and HF-NMES upregulated anabolic signaling with HF-NMES producing a greater anabolic response compared to LF-NMES, suggesting that HF-stimulation may provide a stronger stimulus for processes that initiate muscle hypertrophy. Additionally, the stimulation frequency parameter should be considered by clinicians in the design of optimal NMES treatment protocols.

  20. Centrifugal precipitation chromatography

    Science.gov (United States)

    Ito, Yoichiro; Lin, Qi

    2009-01-01

    Centrifugal precipitation chromatography separates analytes according their solubility in ammonium sulfate (AS) solution and other precipitants. The separation column is made from a pair of long spiral channels partitioned with a semipermeable membrane. In a typical separation, concentrated ammonium sulfate is eluted through one channel while water is eluted through the other channel in the opposite direction. The countercurrent process forms an exponential AS concentration gradient through the water channel. Consequently, protein samples injected into the water channel is subjected to a steadily increasing AS concentration and at the critical AS concentration they are precipitated and deposited in the channel bed by the centrifugal force. Then the chromatographic separation is started by gradually reducing the AS concentration in the AS channel which lowers the AS gradient concentration in the water channel. This results in dissolution of deposited proteins which are again precipitated at an advanced critical point as they move through the channel. Consequently, proteins repeat precipitation and dissolution through a long channel and finally eluted out from the column in the order of their solubility in the AS solution. The present method has been successfully applied to a number of analytes including human serum proteins, recombinant ketosteroid isomerase, carotenoid cleavage enzymes, plasmid DNA, polysaccharide, polymerized pigments, PEG-protein conjugates, etc. The method is capable to single out the target species of proteins by affinity ligand or immunoaffinity separation. PMID:19541553

  1. [A comparative and technical assessment of the HELP system (heparin extracorporeal LDL precipitation) and cascade filtration (CF) for the treatment of high plasma lipids].

    Science.gov (United States)

    Loschiavo, Carmelo

    2013-01-01

    Extracorporeal techniques for the removal of plasma lipids, known as LDL-apheresis, have improved treatment of atherosclerotic lesions in patients with familial hyperlipidemia (FH). In the homozygous form, such treatment is to be considered a life-saving therapy, and in heterozygous forms, which are widely distributed in the population, it is also used when there is a high risk of coronary atherogenic lesions and where a dietary and pharmacological approach has failed to satisfy the objective of a LDL-C 2.6 mmol/L. Of the various techniques available, we believe that cascade filtration (CF) and extracorporeal LDL precipitation with heparin (HELP) are the methods of choice for technical reasons, clinical efficacy and safety. HELP provides, at long-term follow-up, a 5% greater decrease in LDL-C and Lp (a) compared to CF, and about 10% increase in fibrinogen removal resulting in decreased blood viscosity. Conversely, CF produces a concomitant elimination of up to 20% of HDL-C, whereas HELP results in around 5% elimination. CF determines a loss of protein which over time can impact negatively on the protein profile, while HELP results in negligible protein loss. Finally, a significant dampening effect on the intermediate products of inflammation, which initiate the process of vessel atheroma development, has been documented only with HELP. Therefore, the HELP procedure appears to inhibit the development of atheromatous plaques via several different routes.

  2. First Evaluation of the Climatological Calibration Algorithm in the Real-time TMPA Precipitation Estimates over Two Basins at High and Low Latitudes

    Science.gov (United States)

    Yong, Bin; Ren, Liliang; Hong, Yang; Gourley, Jonathan; Tian, Yudong; Huffman, George J.; Chen, Xi; Wang, Weiguang; Wen, Yixin

    2013-01-01

    The TRMM Multi-satellite Precipitation Analysis (TMPA) system underwent a crucial upgrade in early 2009 to include a climatological calibration algorithm (CCA) to its realtime product 3B42RT, and this algorithm will continue to be applied in the future Global Precipitation Measurement era constellation precipitation products. In this study, efforts are focused on the comparison and validation of the Version 6 3B42RT estimates before and after the climatological calibration is applied. The evaluation is accomplished using independent rain gauge networks located within the high-latitude Laohahe basin and the low-latitude Mishui basin, both in China. The analyses indicate the CCA can effectively reduce the systematic errors over the low-latitude Mishui basin but misrepresent the intensity distribution pattern of medium-high rain rates. This behavior could adversely affect TMPA's hydrological applications, especially for extreme events (e.g., floods and landslides). Results also show that the CCA tends to perform slightly worse, in particular, during summer and winter, over the high-latitude Laohahe basin. This is possibly due to the simplified calibration-processing scheme in the CCA that directly applies the climatological calibrators developed within 40 degrees latitude to the latitude belts of 40 degrees N-50 degrees N. Caution should therefore be exercised when using the calibrated 3B42RT for heavy rainfall-related flood forecasting (or landslide warning) over high-latitude regions, as the employment of the smooth-fill scheme in the CCA bias correction could homogenize the varying rainstorm characteristics. Finally, this study highlights that accurate detection and estimation of snow at high latitudes is still a challenging task for the future development of satellite precipitation retrievals.

  3. Study of the diamond and diamond like films formation and technology development for the films precipitation on solid surface for wear resistance increasing of tools, machine and mechanism parts

    International Nuclear Information System (INIS)

    Imanbekov, Z.; Bekmuhambetov, E.

    1996-01-01

    Purpose of the project: The purpose of the project is a development and a creation of an effective technology of the diamond and diamond like films precipitation on materials, including refractory metals, semiconductors and composite on the carbon fibers base. The study method includes the experimental investigation of the base surface structure and properties, preparation of the surface for diamond and diamond like coats growing. The precipitation of above mentioned films will be carried out from the plasma being formed from carbon gas medium at low pressure. The main purposes of the project are: - development of the technology for obtaining the films with specified properties; provision of required rate -of the precipitation; - decreasing of temperature; - manufacturing of the functioning laboratory stand with further developing of a pilot- - commercial plant for diamond and diamond like coating. It is supposed to develop a method of the monocrystal diamond films growing, that are useful for semiconductor devices manufacturing The methods: A thermo-emission and ECR methods will be used for investigation of the diamond and diamond like films formation and growth processes. The plant that will be used for the first method is a two electrode construction. Refractory metals (W,Re) being heated up to 2500 Kelvin degrees, are usually used as an actuating electrode. The second one is a base on which the precipitation is carrying out. Refractory metals, steel, silicon can be used as the base. Actuating medium is a mixture of carbon and inert gases. The second method is based on a principle of a plasma formation with use of 2.45 GHz Shf radiation power. An ECR-plasma is formed in conjunction with magnetic field in the actuating chamber. This method allows to precipitate high quality films at lower pressure. Expected results: The main purpose of the project is to assimilate the high effective technology of the diamond and diamond like films precipitation on different

  4. Towards sustained high oil prices and increasingly volatile

    International Nuclear Information System (INIS)

    Auverlot, Dominique; Teillant, Aude; Rech, Olivier

    2012-09-01

    It is particularly difficult to predict the evolution of global oil production and its ability to meet the demand: the main uncertainties are related to the magnitude of the growth of emerging countries, more or less rapid decline in the production of major oil fields current events as well as natural or accidental, but especially geopolitics, which may affect, at any time, production. In a tight market today, the rapid growth of emerging economies, disruption of the oil supply chain world, even its mere mention, could cause short-term loss of excess production capacity - largely concentrated in Saudi Arabia - an increase substantial progress and, as contemplated by the International Atomic Energy imbalances between global oil supply and demand. If, after 2020, production of conventional oil begins to decline and the demand from emerging markets continues to grow, more massive imbalances may arise, leading to potential geopolitical tensions. Control would then demand the best answer. Otherwise, the resources of unconventional hydrocarbons, considerable expected to meet the demand, provided that their development is fast enough and their operating conditions are environmentally friendly. A consensus is emerging today on keeping oil prices high (above $ 100 / barrel) and volatile in the coming years, allowing some producing countries to pursue their development, but for France amplifying the negative effects on the economic growth oil bill (more than 49 billion euros in 2011) weighs more heavily in our trade deficit. In all cases, climate issues, the weight of the oil bill on our economy, securing our energy supply and technical uncertainties or geopolitical oil production call for reducing our oil consumption, accelerated motion the transition to a low carbon economy and development of our own energy resources. Contents: - Current analysis of oil reserves; - Uncertainties about the evolution of world oil production; - What is the potential long-term oil production

  5. Assimilation of extrapolated radar reflectivity into a NWP model and its impact on a precipitation forecast at high resolution

    Czech Academy of Sciences Publication Activity Database

    Sokol, Zbyněk

    2011-01-01

    Roč. 100, 2-3 (2011), s. 201-212 ISSN 0169-8095 R&D Projects: GA ČR GA205/07/0905; GA MŠk ME09033 Institutional research plan: CEZ:AV0Z30420517 Keywords : Precipitation forecast * Nowcasting * Assimilation of radar reflectivity * Numerical weather prediction * Convective storms Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 1.911, year: 2011 http://www.sciencedirect.com/science/article/pii/S0169809510002462

  6. Novel approach to growth of precipitate-free, high-quality oxide thin films suitable for device applications

    International Nuclear Information System (INIS)

    Endo, K.; Badica, P.; Sato, H.; Akoh, H.

    2006-01-01

    To eliminate precipitates-segregates that can easily occur on the thin film surfaces of the multicomponent materials for electronics, a new approach is proposed, consisting of the following aspects: first, on the substrates, artificial steps of predefined height and width are produced, and second, films are grown on such substrates. The width of the step is taken equal to the 'double of the migration length' of the atomic species depositing on the substrate. In these conditions, precipitates migrate and gather at the step edges where the free energy is lowest and the resulting totally precipitate-free surface of the film on the step is suitable for device applications or integration purposes. The method has several other important advantages and they are discussed in the text. Using this new approach we present successful fabrication of a mesa structure showing intrinsic Josephson effect. We have used thin films of Bi-2212/Bi-2223 superstructure grown by MOCVD on (001) SrTiO 3 single crystal substrates with artificial steps of about 20 μm width

  7. Comparing NEXRAD Operational Precipitation Estimates and Raingage Observations of Intense Precipitation in the Missouri River Basin.

    Science.gov (United States)

    Young, C. B.

    2002-05-01

    Accurate observation of precipitation is critical to the study and modeling of land surface hydrologic processes. NEXRAD radar-based precipitation estimates are increasingly used in field experiments, hydrologic modeling, and water and energy budget studies due to their high spatial and temporal resolution, national coverage, and perceived accuracy. Extensive development and testing of NEXRAD precipitation algorithms have been carried out in the Southern Plains. Previous studies (Young et al. 2000, Young et al. 1999, Smith et al. 1996) indicate that NEXRAD operational products tend to underestimate precipitation at light rain rates. This study investigates the performance of NEXRAD precipitation estimates of high-intensity rainfall, focusing on flood-producing storms in the Missouri River Basin. NEXRAD estimates for these storms are compared with data from multiple raingage networks, including NWS recording and non-recording gages and ALERT raingage data for the Kansas City metropolitan area. Analyses include comparisons of gage and radar data at a wide range of temporal and spatial scales. Particular attention is paid to the October 4th, 1998, storm that produced severe flooding in Kansas City. NOTE: The phrase `NEXRAD operational products' in this abstract includes precipitation estimates generated using the Stage III and P1 algorithms. Both of these products estimate hourly accumulations on the (approximately) 4 km HRAP grid.

  8. Does Increased Coefficient of Friction of Highly Porous Metal Increase Initial Stability at the Acetabular Interface?

    Science.gov (United States)

    Goldman, Ashton H; Armstrong, Lucas C; Owen, John R; Wayne, Jennifer S; Jiranek, William A

    2016-03-01

    Highly porous metal acetabular components illustrate a decreased rate of aseptic loosening in short-term follow-up compared with previous registry data. This study compared the effect of component surface roughness at the bone-implant interface and the quality of the bone on initial pressfit stability. The null hypothesis is that a standard porous coated acetabular cup would show no difference in initial stability as compared with a highly porous acetabular cup when subjected to a bending moment. Second, would bone mineral density (BMD) be a significant variable under these test conditions. In a cadaveric model, acetabular cup micromotion was measured during a 1-time cantilever bending moment applied to 2 generations of pressfit acetabular components. BMD data were also obtained from the femoral necks available for associated specimen. The mean bending moment at 150 μm was not found to be significantly different for Gription (24.6 ± 14.0 N m) cups vs Porocoat (25 ± 10.2 N m; P > .84). The peak bending moment tolerated by Gription cups (33.9 ± 20.3 N m) was not found to be significantly different from Porocoat (33.5 ± 12.2 N m; P > .92). No correlation between BMD and bending moment at 150 μm of displacement could be identified. The coefficient of friction provided by highly porous metal acetabular shells used in this study did not provide better resistance to migration under bending load when compared with a standard porous coated component. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Efforts to increase junior high school students confidencethrough assertive training

    Directory of Open Access Journals (Sweden)

    Romia Hari Susanti

    2016-12-01

    Full Text Available One of important aspects of personality in human life, especially teenagers is confidence. Counseling teachers can increase student confidence through assertive training. Through the training, students are expected to understand that everyone has the right to express their feelings, opinions, beliefs, and attitudes to do a thing without a doubt, but do not hurt other people's feelings, so that confidence can be increased. This study aims to improve students' confidence through assertive training using classroom action research. Subjects in this study were students of SMP Brawijaya Smart School Malang who have low-confidence criteria

  10. Groundwater level responses to precipitation variability in Mediterranean insular aquifers

    Science.gov (United States)

    Lorenzo-Lacruz, Jorge; Garcia, Celso; Morán-Tejeda, Enrique

    2017-09-01

    Groundwater is one of the largest and most important sources of fresh water on many regions under Mediterranean climate conditions, which are exposed to large precipitation variability that includes frequent meteorological drought episodes, and present high evapotranspiration rates and water demand during the dry season. The dependence on groundwater increases in those areas with predominant permeable lithologies, contributing to aquifer recharge and the abundance of ephemeral streams. The increasing pressure of tourism on water resources in many Mediterranean coastal areas, and uncertainty related to future precipitation and water availability, make it urgent to understand the spatio-temporal response of groundwater bodies to precipitation variability, if sustainable use of the resource is to be achieved. We present an assessment of the response of aquifers to precipitation variability based on correlations between the Standardized Precipitation Index (SPI) at various time scales and the Standardized Groundwater Index (SGI) across a Mediterranean island. We detected three main responses of aquifers to accumulated precipitation anomalies: (i) at short time scales of the SPI (24 months). The differing responses were mainly explained by differences in lithology and the percentage of highly permeable rock strata in the aquifer recharge areas. We also identified differences in the months and seasons when aquifer storages are more dependent on precipitation; these were related to climate seasonality and the degree of aquifer exploitation or underground water extraction. The recharge of some aquifers, especially in mountainous areas, is related to precipitation variability within a limited spatial extent, whereas for aquifers located in the plains, precipitation variability influence much larger areas; the topography and geological structure of the island explain these differences. Results indicate large spatial variability in the response of aquifers to precipitation in

  11. Radioresistance increase in polymers at high pressures. [. gamma. rays

    Energy Technology Data Exchange (ETDEWEB)

    Milinchuk, V; KIRJUKHIN, V; KLINSHPONT, E

    1977-06-01

    The effect was studied of very high pressures ranging within 100 and 2,700 MPa on the radioresistance of polytetrafluoroethylene, polypropylene and polyethylene in gamma irradiation. For experiments industrial polymers in the shape of blocks, films and fibers were used. It is shown that in easily breakable polymers, such as polytetrafluoroethylene and polypropylene, 1.3 to 2 times less free radicals are formed as a result of gamma irradiation and a pressure of 150 MPa than at normal pressure. The considerably reduced radiation-chemical formation of radicals and the destruction suppression by cross-linking in polymers is the evidence of the polymer radioresistance in irradiation at high pressures.

  12. Effective Assimilation of Global Precipitation

    Science.gov (United States)

    Lien, G.; Kalnay, E.; Miyoshi, T.; Huffman, G. J.

    2012-12-01

    Assimilating precipitation observations by modifying the moisture and sometimes temperature profiles has been shown successful in forcing the model precipitation to be close to the observed precipitation, but only while the assimilation is taking place. After the forecast start, the model tends to "forget" the assimilation changes and lose their extra skill after few forecast hours. This suggests that this approach is not an efficient way to modify the potential vorticity field, since this is the variable that the model would remember. In this study, the ensemble Kalman filter (EnKF) method is used to effectively change the potential vorticity field by allowing ensemble members with better precipitation to receive higher weights. In addition to using an EnKF, two other changes in the precipitation assimilation process are proposed to solve the problems related to the highly non-Gaussian nature of the precipitation variable: a) transform precipitation into a Gaussian distribution based on its climatological distribution, and b) only assimilate precipitation at the location where some ensemble members have positive precipitation. The idea is first tested by the observing system simulation experiments (OSSEs) using SPEEDY, a simplified but realistic general circulation model. When the global precipitation is assimilated in addition to conventional rawinsonde observations, both the analyses and the medium range forecasts are significantly improved as compared to only having rawinsonde observations. The improvement is much reduced when only modifying the moisture field with the same approach, which shows the importance of the error covariance between precipitation and all other model variables. The effect of precipitation assimilation is larger in the Southern Hemisphere than that in the Northern Hemisphere because the Northern Hemisphere analyses are already accurate as a result of denser rawinsonde stations. Assimilation of precipitation using a more comprehensive

  13. Increase of cerebral blood flow at high altitude

    DEFF Research Database (Denmark)

    Lassen, N A

    1992-01-01

    but rather somewhat sharpened over five days at almost 4000 meters of altitude. This, along with other evidence, shows that CBF does not in itself adapt to chronic hypoxia. Nevertheless, a decrease in CBF is seen over days at constant altitude primarily due to increase in the hematocrit. The cerebral...

  14. Coupling diffusion and high-pH precipitation/dissolution in the near field of a HLW repository in clay by means of reactive solute transport models

    Science.gov (United States)

    Samper, J.; Font, I.; Yang, C.; Montenegro, L.

    2004-12-01

    The reference concept for a HLW repository in clay in Spain includes a 75 cm thick bentonite buffer which surrounds canisters. A concrete sustainment 20 cm thick is foreseen between the bentonite buffer and the clay formation. The long term geochemical evolution of the near field is affected by a high-pH hyperalkaline plume induced by concrete. Numerical models of multicomponent reactive transport have been developped in order to quantify the evolution of the system over 1 Ma. Water flow is negligible once the bentonite buffer is saturated after about 20 years. Therefore, solute transport occurs mainly by diffusion. Models account for aqueous complexation, acid-base and redox reactions, cation exchange, and mineral dissolution precipitation in the bentonite, the concrete and the clay formation. Numerical results obtained witth CORE2D indicate that the high-pH plume causes significant changes in porewater chemistry both in the bentonite buffer and the clay formation. Porosity changes caused by mineral dissolution/precipitation are extremely important. Therefore, coupled modes of diffusion and reactive transport accounting for changes in porosity caused by mineral precipitation are required in order to obtain realistic predictions.

  15. Precipitation from Space: Advancing Earth System Science

    Science.gov (United States)

    Kucera, Paul A.; Ebert, Elizabeth E.; Turk, F. Joseph; Levizzani, Vicenzo; Kirschbaum, Dalia; Tapiador, Francisco J.; Loew, Alexander; Borsche, M.

    2012-01-01

    otherwise possible. These developments have taken place in parallel with the growth of an increasingly interconnected scientific environment. Scientists from different disciplines can easily interact with each other via information and materials they encounter online, and collaborate remotely without ever meeting each other in person. Likewise, these precipitation datasets are quickly and easily available via various data portals and are widely used. Within the framework of the NASA/JAXA Global Precipitation Measurement (GPM mission, these applications will become increasingly interconnected. We emphasize that precipitation observations by themselves provide an incomplete picture of the state of the atmosphere. For example, it is unlikely that a richer understanding of the global water cycle will be possible by standalone missions and algorithms, but must also involve some component of data, where model analyses of the physical state are constrained alongside multiple observations (e.g., precipitation, evaporation, radiation). The next section provides examples extracted from the many applications that use various high-resolution precipitation products. The final section summarizes the future system for global precipitation processing.

  16. Lens autofluorescence is not increased at high altitude

    DEFF Research Database (Denmark)

    Kessel, Line; Kofoed, Peter Kristian; Zubieta-Calleja, Gustavo

    2010-01-01

    in Denmark. RESULTS: No significant differences in lens fluorescence or transmittance were found between Bolivian and Danish volunteers. CONCLUSION: Age-corrected lens fluorescence and transmittance were comparable for healthy participants living at high altitude near the equator and healthy volunteers...

  17. Interactive Online Physics Labs Increase High School Students' Interest

    Science.gov (United States)

    Gryczka, Patrick; Klementowicz, Edward; Sharrock, Chappel; Montclare, Jin Kim

    2016-01-01

    Here we describe the incorporation of a web-based application focusing on circuits for the physics high school classroom as part of an outreach program. The program involves college mentors creating and implementing science lessons in collaboration with the classroom teacher. Focusing on the challenge of understanding circuit design, a technology…

  18. Merging Radar Quantitative Precipitation Estimates (QPEs) from the High-resolution NEXRAD Reanalysis over CONUS with Rain-gauge Observations

    Science.gov (United States)

    Prat, O. P.; Nelson, B. R.; Stevens, S. E.; Nickl, E.; Seo, D. J.; Kim, B.; Zhang, J.; Qi, Y.

    2015-12-01

    The processing of radar-only precipitation via the reanalysis from the National Mosaic and Multi-Sensor Quantitative (NMQ/Q2) based on the WSR-88D Next-generation Radar (Nexrad) network over the Continental United States (CONUS) is completed for the period covering from 2002 to 2011. While this constitutes a unique opportunity to study precipitation processes at higher resolution than conventionally possible (1-km, 5-min), the long-term radar-only product needs to be merged with in-situ information in order to be suitable for hydrological, meteorological and climatological applications. The radar-gauge merging is performed by using rain gauge information at daily (Global Historical Climatology Network-Daily: GHCN-D), hourly (Hydrometeorological Automated Data System: HADS), and 5-min (Automated Surface Observing Systems: ASOS; Climate Reference Network: CRN) resolution. The challenges related to incorporating differing resolution and quality networks to generate long-term large-scale gridded estimates of precipitation are enormous. In that perspective, we are implementing techniques for merging the rain gauge datasets and the radar-only estimates such as Inverse Distance Weighting (IDW), Simple Kriging (SK), Ordinary Kriging (OK), and Conditional Bias-Penalized Kriging (CBPK). An evaluation of the different radar-gauge merging techniques is presented and we provide an estimate of uncertainty for the gridded estimates. In addition, comparisons with a suite of lower resolution QPEs derived from ground based radar measurements (Stage IV) are provided in order to give a detailed picture of the improvements and remaining challenges.

  19. Increased Risk of Drug-Induced Hyponatremia during High Temperatures

    Directory of Open Access Journals (Sweden)

    Anna K Jönsson

    2017-07-01

    Full Text Available Purpose: To investigate the relationship between outdoor temperature in Sweden and the reporting of drug-induced hyponatremia to the Medical Products Agency (MPA. Methods: All individual adverse drug reactions (ADR reported to MPA from 1 January 2010 to 31 October 2013 of suspected drug-induced hyponatremia and random controls were identified. Reports where the ADR had been assessed as having at least a possible relation to the suspected drug were included. Information on administered drugs, onset date, causality assessment, sodium levels, and the geographical origin of the reports was extracted. A case-crossover design was used to ascertain the association between heat exposure and drug-induced hyponatremia at the individual level, while linear regression was used to study its relationship to sodium concentration in blood. Temperature exposure data were obtained from the nearest observation station to the reported cases. Results: During the study period, 280 reports of hyponatremia were identified. More cases of drug-induced hyponatremia were reported in the warmer season, with a peak in June, while other ADRs showed an opposite annual pattern. The distributed lag non-linear model indicated an increasing odds ratio (OR with increasing temperature in the warm season with a highest odds ratio, with delays of 1–5 days after heat exposure. A cumulative OR for a lag time of 1 to 3 days was estimated at 2.21 at an average daily temperature of 20 °C. The change in sodium per 1 °C increase in temperature was estimated to be −0.37 mmol/L (95% CI: −0.02, −0.72. Conclusions: Warm weather appears to increase the risk of drug-induced hyponatremia

  20. Application of a PEG precipitation method for solubility screening: A tool for developing high protein concentration formulations

    OpenAIRE

    Li, Li; Kantor, Angela; Warne, Nicholas

    2013-01-01

    Previous publications demonstrated that the extrapolated solubility by polyethylene glycol (PEG) precipitation method (Middaugh et al., J Biol Chem 1979; 254:367–370; Juckes, Biochim Biophys Acta 1971; 229:535–546; Foster et al., Biochim Biophys Acta 1973; 317:505; Mahadevan and Hall, AIChE J 1990; 36:1517–1528; Stevenson and Hageman, Pharm Res 1995; 12:1671–1676) has a strong correlation to experimentally measured solubility of proteins. Here, we explored the utility of extrapolated solubili...

  1. The trial of obtaining a high-grade gadolinium concentrate using the fractional precipitation together with the ion exchange

    International Nuclear Information System (INIS)

    Ozga, W.; Soltysiak, I.

    1980-01-01

    The modified fractional precipitation of lanthanon-potassium double chromate was used for preliminary separation of gadolinium concentrate containing 60% Gd 2 O 3 , 33,3% Sm 2 O 3 . The 1-st fraction enriched with samarium (60% Sm 2 O 3 ) and 2-nd fraction enriched with gadolinium (80% Gd 2 O 3 with efficiency of 82% recounting on Gd 2 O 3 ) were obtained. Both fractions were separated by the elution with EDTA solution buffered with ammonium acetate. The good results were obtained by ion exchange separation only of the 1-st fraction. (author)

  2. How a high working memory capacity can increase proactive interference.

    Science.gov (United States)

    Steinwascher, Merle A; Meiser, Thorsten

    2016-08-01

    Previous findings suggested that a high working memory capacity (WMC) is potentially associated with a higher susceptibility to proactive interference (PI) if the latter is measured under high cognitive load. To explain such a finding, we propose to consider susceptibility to PI as a net effect of individual executive processes and the intrinsic potential for PI. With the latter, we refer to the amount of information that is activated at a given time and that has the potential to exert PI subsequently. In two studies deploying generalized linear mixed models, susceptibility to PI was modeled as the decline of performance over trials of a complex span task. The results revealed that a higher WMC was associated with a higher susceptibility to PI. Moreover, the number of stimuli recalled in one trial as a proxy variable for the intrinsic potential for PI negatively affected memory performance in the subsequent trial. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Regional climate scenarios - A study on precipitation

    International Nuclear Information System (INIS)

    Hesselbjerg Christensen, J.; Boessing Christensen, O.

    2001-01-01

    A set of nested climate change simulations for the Nordic region and Denmark has been revisited. In the present work we have re-examined the results of CCMB and MBC with special emphasis on precipitation intensity frequencies, in particular the more extreme part of the frequency distribution. It has been demonstrated that the role of extreme precipitation events appears to be more realistically described in a high-resolution model, in terms of numerical agreement as well as seasonal variation. This is mainly due to a better simulation of deep low-pressure systems and mesoscale circulation. Generally, the analysis has confirmed the results from CCMB, but furthermore a resolution effect has been identified which seems essential to the understanding of climate change effects on the extreme end of the precipitation intensity distribution. In order to analyse the role of the model resolution we have aggregated both the nested model data and observational records to the GCM grid from the driving AOGCM. It was found that, in spite of changes in absolute numbers, the seasonal behaviour of decay constants does not change appreciably because of the aggregation. The RCM results show a seasonal behaviour very similar to an observed data set. It is therefore concluded that the GCM has an unrealistic simulation of the dependence of heavy precipitation on climate, as manifested in seasonal variation. In contrast, the regional simulations remain close to observation in this respect. Furthermore, they agree on a conclusion that extreme precipitation generally scales with average precipitation (no significant change in decay constants were detected), but that crucial summer season may be an exception, exhibiting an anomalous increase in heavy precipitation due to the anthropogenic greenhouse effect. The analysis has only been performed over Denmark due to lack of daily observational data for other regions. It is, however, necessary to extend the work to other areas, for instance

  4. Correction of Excessive Precipitation over Steep and High Mountains in a GCM: A Simple Method of Parameterizing the Thermal Effects of Subgrid Topographic Variation

    Science.gov (United States)

    Chao, Winston C.

    2015-01-01

    The excessive precipitation over steep and high mountains (EPSM) in GCMs and meso-scale models is due to a lack of parameterization of the thermal effects of the subgrid-scale topographic variation. These thermal effects drive subgrid-scale heated slope induced vertical circulations (SHVC). SHVC provide a ventilation effect of removing heat from the boundary layer of resolvable-scale mountain slopes and depositing it higher up. The lack of SHVC parameterization is the cause of EPSM. The author has previously proposed a method of parameterizing SHVC, here termed SHVC.1. Although this has been successful in avoiding EPSM, the drawback of SHVC.1 is that it suppresses convective type precipitation in the regions where it is applied. In this article we propose a new method of parameterizing SHVC, here termed SHVC.2. In SHVC.2 the potential temperature and mixing ratio of the boundary layer are changed when used as input to the cumulus parameterization scheme over mountainous regions. This allows the cumulus parameterization to assume the additional function of SHVC parameterization. SHVC.2 has been tested in NASA Goddard's GEOS-5 GCM. It achieves the primary goal of avoiding EPSM while also avoiding the suppression of convective-type precipitation in regions where it is applied.

  5. Interaction between recrystallization and strain-induced precipitation in a high Nb- and N-bearing austenitic stainless steel: Influence of the interpass time

    Energy Technology Data Exchange (ETDEWEB)

    Silva, M.B.R., E-mail: marianabdrs@gmail.com [Department of Materials Engineering, UFSCar, Via Washington Luis, Km 235, 13565-905 São Carlos, SP (Brazil); Gallego, J. [Department of Mechanical Engineering, UNESP, Avenida Brasil, 56, 15385-000 Ilha Solteira, SP (Brazil); Cabrera, J.M. [Department of Materials Science and Metallurgical Engineering, Polytechnic University of Catalunya, Avenida Diagonal 647, 08028 Barcelona (Spain); Fundacio CTM Centre Tecnologic, Plaza de la Ciencia 2, 08243 Manresa (Spain); Balancin, O. [Department of Materials Engineering, UFSCar, Via Washington Luis, Km 235, 13565-905 São Carlos, SP (Brazil); Jorge, A.M., E-mail: moreira@dema.ufscar.br [Department of Materials Engineering, UFSCar, Via Washington Luis, Km 235, 13565-905 São Carlos, SP (Brazil)

    2015-06-18

    In this work, we studied the influence of the interpass time (20 and 5 s) on the interaction between recrystallization and strain-induced precipitation occurring during multiple passes' deformations under continuous cooling conditions in a high niobium- and nitrogen-bearing austenitic stainless steel (ISO 5832-9). The correlation between microstructure evolution and hot mechanical properties was performed by physical simulation using hot torsion tests. The microstructure evolution was analyzed by optical microscopy, transmission electron microscopy and electron back scattered diffraction (EBSD). This technique indicated that dynamic recrystallization occurred at the first passes promoting an excellent grain refinement. On the other hand, shorter interpass time (5 s) allowed higher volume fraction of smallest precipitates than larger interpass time (20 s). After soaking, only TiNbN precipitates were found, whereas, Z-phase (CrNbN) and NbN were formed during thermomechanical processing. Particles with sizes between 20 and 50 nm were effective to pin grain boundaries and dislocations.

  6. High epitope expression levels increase competition between T cells.

    Directory of Open Access Journals (Sweden)

    Almut Scherer

    2006-08-01

    Full Text Available Both theoretical predictions and experimental findings suggest that T cell populations can compete with each other. There is some debate on whether T cells compete for aspecific stimuli, such as access to the surface on antigen-presenting cells (APCs or for specific stimuli, such as their cognate epitope ligand. We have developed an individual-based computer simulation model to study T cell competition. Our model shows that the expression level of foreign epitopes per APC determines whether T cell competition is mainly for specific or aspecific stimuli. Under low epitope expression, competition is mainly for the specific epitope stimuli, and, hence, different epitope-specific T cell populations coexist readily. However, if epitope expression levels are high, aspecific competition becomes more important. Such between-specificity competition can lead to competitive exclusion between different epitope-specific T cell populations. Our model allows us to delineate the circumstances that facilitate coexistence of T cells of different epitope specificity. Understanding mechanisms of T cell coexistence has important practical implications for immune therapies that require a broad immune response.

  7. Combined use of an electrostatic precipitator and a high-efficiency particulate air filter in building ventilation systems: Effects on cardiorespiratory health indicators in healthy adults.

    Science.gov (United States)

    Day, D B; Xiang, J; Mo, J; Clyde, M A; Weschler, C J; Li, F; Gong, J; Chung, M; Zhang, Y; Zhang, J

    2018-05-01

    High-efficiency particulate air (HEPA) filtration in combination with an electrostatic precipitator (ESP) can be a cost-effective approach to reducing indoor particulate exposure, but ESPs produce ozone. The health effect of combined ESP-HEPA filtration has not been examined. We conducted an intervention study in 89 volunteers. At baseline, the air-handling units of offices and residences for all subjects were comprised of coarse, ESP, and HEPA filtration. During the 5-week long intervention, the subjects were split into 2 groups, 1 with just the ESP removed and the other with both the ESP and HEPA removed. Each subject was measured for cardiopulmonary risk indicators once at baseline, twice during the intervention, and once 2 weeks after baseline conditions were restored. Measured indoor and outdoor PM 2.5 and ozone concentrations, coupled with time-activity data, were used to calculate exposures. Removal of HEPA filters increased 24-hour mean PM 2.5 exposure by 38 (95% CI: 31, 45) μg/m 3 . Removal of ESPs decreased 24-hour mean ozone exposure by 2.2 (2.0, 2.5) ppb. No biomarkers were significantly associated with HEPA filter removal. In contrast, ESP removal was associated with a -16.1% (-21.5%, -10.4%) change in plasma-soluble P-selectin and a -3.0% (-5.1%, -0.8%) change in systolic blood pressure, suggesting reduced cardiovascular risks. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Synoptic Drivers of Precipitation in the Atlantic Sector of the Arctic

    Science.gov (United States)

    Cohen, L.; Hudson, S.; Graham, R.; Renwick, J. A.

    2017-12-01

    Precipitation in the Arctic has been shown to be increasing in recent decades, from both observational and modelling studies, with largest trends seen in autumn and winter. This trend is attributed to a combination of the warming atmosphere and reduced sea ice extent. The seasonality of precipitation in the Arctic is important as it largely determines whether the precipitation falls as snow or rain. This study assesses the spatial and temporal variability of the synoptic drivers of precipitation in the Atlantic (European) sector of the Arctic. This region of the Arctic is of particular interest as it has the largest inter-annual variability in sea ice extent and is the primary pathway for moisture transport into the Arctic from lower latitudes. This study uses the ECMWF ERA-I reanalysis total precipitation to compare to long-term precipitation observations from Ny Ålesund, Svalbard to show that the reanalysis captures the synoptic variability of precipitation well and that most precipitation in this region is synoptically driven. The annual variability of precipitation in the Atlantic Arctic shows strong regionality. In the Svalbard and Barents Sea region, most of the annual total precipitation occurs during autumn and winter (Oct-Mar) (>60% of annual total), while the high-Arctic (> 80N) and Kara Sea receives most of the annual precipitation ( 60% of annual total) during summer (July-Sept). Using a synoptic classification developed for this region, this study shows that winter precipitation is driven by winter cyclone occurrence, with strong correlations to the AO and NAO indices. High precipitation over Svalbard is also strongly correlated with the Scandinavian blocking pattern, which produces a southerly flow in the Greenland Sea/Svalbard area. An increasing occurrence of these synoptic patterns are seen for winter months (Nov and Jan), which may explain much of the observed winter increase in precipitation.

  9. Maximizing recovery of water-soluble proteins through acetone precipitation.

    Science.gov (United States)

    Crowell, Andrew M J; Wall, Mark J; Doucette, Alan A

    2013-09-24

    Solvent precipitation is commonly used to purify protein samples, as seen with the removal of sodium dodecyl sulfate through acetone precipitation. However, in its current practice, protein loss is believed to be an inevitable consequence of acetone precipitation. We herein provide an in depth characterization of protein recovery through acetone precipitation. In 80% acetone, the precipitation efficiency for six of 10 protein standards was poor (ca. ≤15%). Poor recovery was also observed for proteome extracts, including bacterial and mammalian cells. As shown in this work, increasing the ionic strength of the solution dramatically improves the precipitation efficiency of individual proteins, and proteome mixtures (ca. 80-100% yield). This is obtained by including 1-30 mM NaCl, together with acetone (50-80%) which maximizes protein precipitation efficiency. The amount of salt required to restore the recovery correlates with the amount of protein in the sample, as well as the intrinsic protein charge, and the dielectric strength of the solution. This synergistic approach to protein precipitation in acetone with salt is consistent with a model of ion pairing in organic solvent, and establishes an improved method to recover proteins and proteome mixtures in high yield. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Magnetite precipitation and characterisation

    International Nuclear Information System (INIS)

    Joyce, A.; Garside, J.; Ivens, R.

    1988-06-01

    Magnetite (Fe 3 O 4 ) precipitation was investigated as a possible alternative treatment process to the conventional ferric hydroxide for removal of actinides from radioactive effluents. This offered the possibility of improved dewatering of filtered residues. Whilst a poor quality magnetite could be produced from deoxygenated ferrous/ferric solutions, all attempts to prepare magnetite from effluent simulates were unsuccessful. The failure was attributed to the presence of high nitrate and other interfering ions. (author)

  11. Chitosan-coated magnetic nanoparticles prepared in one-step by precipitation in a high-aqueous phase content reverse microemulsion.

    Science.gov (United States)

    Pineda, María Guadalupe; Torres, Silvia; López, Luis Valencia; Enríquez-Medrano, Francisco Javier; de León, Ramón Díaz; Fernández, Salvador; Saade, Hened; López, Raúl Guillermo

    2014-07-02

    Chitosan-coated magnetic nanoparticles (CMNP) were prepared in one-step by precipitation in a high-aqueous phase content reverse microemulsion in the presence of chitosan. The high-aqueous phase concentration led to productivities close to 0.49 g CMNP/100 g microemulsion; much higher than those characteristic of precipitation in reverse microemulsions for preparing magnetic nanoparticles. The obtained nanoparticles present a narrow particle size distribution with an average diameter of 4.5 nm; appearing to be formed of a single crystallite; furthermore they present superparamagnetism and high magnetization values; close to 49 emu/g. Characterization of CMNP suggests that chitosan is present as a non-homogeneous very thin layer; which explains the slight reduction in the magnetization value of CMNP in comparison with that of uncoated magnetic nanoparticles. The prepared nanoparticles show high heavy ion removal capability; as demonstrated by their use in the treatment of Pb2+ aqueous solutions; from which lead ions were completely removed within 10 min.

  12. Chitosan-Coated Magnetic Nanoparticles Prepared in One-Step by Precipitation in a High-Aqueous Phase Content Reverse Microemulsion

    Directory of Open Access Journals (Sweden)

    María Guadalupe Pineda

    2014-07-01

    Full Text Available Chitosan-coated magnetic nanoparticles (CMNP were prepared in one-step by precipitation in a high-aqueous phase content reverse microemulsion in the presence of chitosan. The high-aqueous phase concentration led to productivities close to 0.49 g CMNP/100 g microemulsion; much higher than those characteristic of precipitation in reverse microemulsions for preparing magnetic nanoparticles. The obtained nanoparticles present a narrow particle size distribution with an average diameter of 4.5 nm; appearing to be formed of a single crystallite; furthermore they present superparamagnetism and high magnetization values; close to 49 emu/g. Characterization of CMNP suggests that chitosan is present as a non-homogeneous very thin layer; which explains the slight reduction in the magnetization value of CMNP in comparison with that of uncoated magnetic nanoparticles. The prepared nanoparticles show high heavy ion removal capability; as demonstrated by their use in the treatment of Pb2+ aqueous solutions; from which lead ions were completely removed within 10 min.

  13. Definition of a temporal distribution index for high temporal resolution precipitation data over Peninsular Spain and the Balearic Islands: the fractal dimension; and its synoptic implications

    Science.gov (United States)

    Meseguer-Ruiz, Oliver; Osborn, Timothy J.; Sarricolea, Pablo; Jones, Philip D.; Cantos, Jorge Olcina; Serrano-Notivoli, Roberto; Martin-Vide, Javier

    2018-03-01

    Precipitation on the Spanish mainland and in the Balearic archipelago exhibits a high degree of spatial and temporal variability, regardless of the temporal resolution of the data considered. The fractal dimension indicates the property of self-similarity, and in the case of this study, wherein it is applied to the temporal behaviour of rainfall at a fine (10-min) resolution from a total of 48 observatories, it provides insights into its more or less convective nature. The methodology of Jenkinson & Collison which automatically classifies synoptic situations at the surface, as well as an adaptation of this methodology at 500 hPa, was applied in order to gain insights into the synoptic implications of extreme values of the fractal dimension. The highest fractal dimension values in the study area were observed in places with precipitation that has a more random behaviour over time with generally high totals. Four different regions in which the atmospheric mechanisms giving rise to precipitation at the surface differ from the corresponding above-ground mechanisms have been identified in the study area based on the fractal dimension. In the north of the Iberian Peninsula, high fractal dimension values are linked to a lower frequency of anticyclonic situations, whereas the opposite occurs in the central region. In the Mediterranean, higher fractal dimension values are associated with a higher frequency of the anticyclonic type and a lower frequency of the advective type from the east. In the south, lower fractal dimension values indicate higher frequency with respect to the anticyclonic type from the east and lower frequency with respect to the cyclonic type.

  14. Influence of Mn-dopant on the properties of α-FeOOH particles precipitated in highly alkaline media

    International Nuclear Information System (INIS)

    Krehula, Stjepko; Music, Svetozar

    2006-01-01

    The effects of Mn-dopant on the formation of solid solutions α-(Fe, Mn)OOH in dependence on the initial concentration ratio r = [Mn]/([Mn] + [Fe]), as well as on the size and morphology of the corresponding particles were investigated using Moessbauer and FT-IR spectroscopies, high-resolution scanning electron microscopy (FE SEM) and an energy dispersive X-ray analyser (EDS). The value of the hyperfine magnetic field of 34.9 T, as recorded for the reference α-FeOOH sample at RT, decreased linearly up to 21.4 T for sample with r = 0.1667. Only a paramagnetic doublet at RT was recorded for sample with r = 0.2308, a ferrite phase was additionally found for r = 0.3333. Fe-OH bending IR bands, δ OH and γ OH , were influenced by the Mn-substitution as manifested through their gradual shifts. FE SEM micrographs showed a great elongation of the starting acicular particles along the c-axis with an increase in Mn-doping. For r = 0.1667 and 0.2308 star-shaped and dendritic twin α-(Fe, Mn)OOH particles were observed. The length of these α-(Fe, Mn)OOH particles decreased, whereas their width increased. The α-Fe 2 O 3 phase was not detected in any of the samples prepared

  15. Rain-season trends in precipitation and their effect in different climate regions of China during 1961-2008

    International Nuclear Information System (INIS)

    Song Yanling; Achberger, Christine; Linderholm, Hans W

    2011-01-01

    Using high-quality precipitation data from 524 stations, the trends of a set of precipitation variables during the main rain season (May-September) from 1961 to 2008 for different climate regions in China were analysed. However, different characteristics were displayed in different regions of China. In most temperate monsoon regions (north-eastern China), total rain-season precipitation and precipitation days showed decreasing trends; positive tendencies in precipitation intensity were, however, noted for most stations in this region. It is suggested that the decrease in rain-season precipitation is mainly related to there being fewer rain days and a change towards drier conditions in north-eastern China, and as a result, the available water resources have been negatively affected in the temperate monsoon regions. In most subtropical and tropical monsoon climate regions (south-eastern China), the rain-season precipitation and precipitation days (11-50, with > 50 mm) showed slightly positive trends. However, precipitation days with ≤ 10 mm decreased in these regions. Changes towards wetter conditions in this area, together with more frequent heavy rainfall events causing floods, have a severe impact on peoples' lives and socio-economic development. In general, the rain-season precipitation, precipitation days and rain-season precipitation intensity had all increased in the temperate continental and plateau/mountain regions of western China. This increase in rain-season precipitation has been favourable to pasture growth.

  16. Do competitors modulate rare plant response to precipitation change?

    Science.gov (United States)

    Levine, J.M.; Kathryn, Mceachern A.; Cowan, C.

    2010-01-01

    Ecologists increasingly suspect that climate change will directly impact species physiology, demography, and phenology, but also indirectly affect these measures via changes to the surrounding community. Unfortunately, few studies examine both the direct and indirect pathways of impact. Doing so is important because altered competitive pressures can reduce or magnify the direct responses of a focal species to climate change. Here, we examine the effects of changing rainfall on three rare annual plant species in the presence and absence of competition on the California Channel Islands. We used rain-out shelters and hand watering to exclude and augment early, late, and season-long rainfall, spanning the wide range of precipitation change forecast for the region. In the absence of competition, droughts reduced the population growth rates of two of three focal annuals, while increased rainfall was only sometimes beneficial, As compared to the focal species, the dominant competitors were more sensitive to the precipitation treatments, benefiting from increased season-long precipitation and harmed by droughts. Importantly, the response of two of three competitors to the precipitation treatments tended to be positively correlated with those of the focal annuals. Although this leads to the expectation that increased competition will counter the direct benefits of favorable conditions, such indirect effects of precipitation change proved weak to nonexistent in our experiment. Competitors had little influence on the precipitation response of two focal species, due to their low sensitivity to competition and highly variable precipitation responses. Competition did affect how our third focal species responded to precipitation change, but this effect only approached significance, and whether it truly resulted from competitor response to precipitation change was unclear. Our work suggests that even when competitors respond to climate change, these responses may have little

  17. The Contribution of Extreme Precipitation to the Total Precipitation in China

    Institute of Scientific and Technical Information of China (English)

    SUN Jian-Qi

    2012-01-01

    Using daily precipitation data from weather stations in China, the variations in the contribution of extreme precipitation to the total precipitation are analyzed. It is found that extreme precipitation accounts for approximately one third of the total precipitation based on the overall mean for China. Over the past half century, extreme precipitation has played a dominant role in the year-to-year variability of the total precipitation. On the decadal time scale, the extreme precipitation makes different contributions to the wetting and drying regions of China. The wetting trends of particular regions are mainly attributed to increases in extreme precipitation; in contrast, the drying trends of other regions are mainly due to decreases in non-extreme precipitation.

  18. Assessing changes in extreme convective precipitation from a damage perspective

    Science.gov (United States)

    Schroeer, K.; Tye, M. R.

    2016-12-01

    Projected increases in high-intensity short-duration convective precipitation are expected even in regions that are likely to become more arid. Such high intensity precipitation events can trigger hazardous flash floods, debris flows and landslides that put people and local assets at risk. However, the assessment of local scale precipitation extremes is hampered by its high spatial and temporal variability. In addition to which, not only are extreme events rare, but such small scale events are likely to be underreported where they don't coincide with the observation network. Rather than focus solely on the convective precipitation, understanding the characteristics of these extremes which drive damage may be more effective to assess future risks. Two sources of data are used in this study. First, sub-daily precipitation observations over the Southern Alps enable an examination of seasonal and regional patterns in high-intensity convective precipitation and their relationship with weather types. Secondly, reports of private loss and damage on a household scale are used to identify which events are most damaging, or what conditions potentially enhance the vulnerability to these extremes.This study explores the potential added value from including recorded loss and damage data to understand the risks from summertime convective precipitation events. By relating precipitation generating weather types to the severity of damage we hope to develop a mechanism to assess future risks. A further benefit would be to identify from damage reports the likely occurrence of precipitation extremes where no direct observations are available and use this information to validate remotely sensed observations.

  19. Acidity of Scandinavian precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, E; Bordin, G

    1955-01-01

    Data on the pH of the total monthly precipitation at stations of a Swedish network for sampling and chemical analysis of precipitation and atmospheric aerosols during the year July 1953 to June 1954 are presented and discussed, together with the pH data from the first two months of operation of a large pan-Scandinavian net. It is found that well-defined regions of acidity and alkalinity relative to the pH of water in equilibrium with atmospheric carbon dioxide exist, and that these regions persist to such an extent that the monthly deviations from the pattern of the annual mean pH at stations unaffected by local pollution show persistently high acidity, while inland northern stations show equally persistent alkalinity. Some possible reasons for the observed distributions are considered.

  20. Extract of mangosteen increases high density lipoprotein levels in rats fed high lipid

    Directory of Open Access Journals (Sweden)

    Dwi Laksono Adiputro

    2013-04-01

    Full Text Available Background In cardiovascular medicine, Garcinia mangostana has been used as an antioxidant to inhibit oxidation of low density lipoproteins and as an antiobesity agent. The effect of Garcinia mangostana on hyperlipidemia is unknown. The aim of this study was to evaluate the effect of an ethanolic extract of Garcinia mangostana pericarp on lipid profile in rats fed a high lipid diet. Methods A total of 40 rats were divided into five groups control, high lipid diet, and high lipid diet + ethanolic extract of Garcinia mangostana pericarp at dosages of 200, 400, and 800 mg/kg body weight. The control group received a standard diet for 60 days. The high lipid diet group received standard diet plus egg yolk, goat fat, cholic acid, and pig fat for 60 days with or without ethanolic extract of Garcinia mangostana pericarp by the oral route. After 60 days, rats were anesthesized with ether for collection of blood by cardiac puncture. Analysis of blood lipid profile comprised colorimetric determination of cholesterol, triglyceride, low density lipoprotein (LDL, and high density lipoprotein (HDL. Results From the results of one-way ANOVA it was concluded that there were significant between-group differences in cholesterol, trygliceride, LDL, and HDL levels (p=0.000. Ethanolic extract of Garcinia mangostana pericarp significantly decreased cholesterol, trygliceride, and LDL levels, starting at 400 mg/kg body weight (p=0.000. Ethanolic extract of Garcinia mangostana pericarp significantly increased HDL level starting at 200 mg/kg body weight (p=0.000. Conclusion Ethanolic extract of Garcinia mangostana pericarp has a beneficial effect on lipid profile in rats on a high lipid diet.

  1. Extract of mangosteen increases high density lipoprotein levels in rats fed high lipid

    Directory of Open Access Journals (Sweden)

    Dwi Laksono Adiputro

    2015-12-01

    Full Text Available BACKGROUND In cardiovascular medicine, Garcinia mangostana has been used as an antioxidant to inhibit oxidation of low density lipoproteins and as an antiobesity agent. The effect of Garcinia mangostana on hyperlipidemia is unknown. The aim of this study was to evaluate the effect of an ethanolic extract of Garcinia mangostana pericarp on lipid profile in rats fed a high lipid diet. METHODS A total of 40 rats were divided into five groups control, high lipid diet, and high lipid diet + ethanolic extract of Garcinia mangostana pericarp at dosages of 200, 400, and 800 mg/kg body weight. The control group received a standard diet for 60 days. The high lipid diet group received standard diet plus egg yolk, goat fat, cholic acid, and pig fat for 60 days with or without ethanolic extract of Garcinia mangostana pericarp by the oral route. After 60 days, rats were anesthesized with ether for collection of blood by cardiac puncture. Analysis of blood lipid profile comprised colorimetric determination of cholesterol, triglyceride, low density lipoprotein (LDL, and high density lipoprotein (HDL. RESULTS From the results of one-way ANOVA it was concluded that there were significant between-group differences in cholesterol, trygliceride, LDL, and HDL levels (p=0.000. Ethanolic extract of Garcinia mangostana pericarp significantly decreased cholesterol, trygliceride, and LDL levels, starting at 400 mg/kg body weight (p=0.000. Ethanolic extract of Garcinia mangostana pericarp significantly increased HDL level starting at 200 mg/kg body weight (p=0.000. CONCLUSION Ethanolic extract of Garcinia mangostana pericarp has a beneficial effect on lipid profile in rats on a high lipid diet.

  2. Stress corrosion cracking of stainless steel under deaerated high-temperature water. Influence of grain boundary carbide precipitation

    International Nuclear Information System (INIS)

    Yamada, Takuyo; Terachi, Takumi; Arioka, Koji

    2006-01-01

    In order to evaluate the influence of grain boundary carbide on IGSCC susceptibility, crack growth rate tests were performed under deaerated and 0.3 ppm hydrogenated pure water environments at 320degC using half-inch compact tension specimens. To investigate various grain boundary carbide conditions, three kinds of SUS316 - non-sensitized, sensitized at 650degC for 1 hour or 48 hours - were prepared. To examine the influence of grain boundary carbide, the grain boundary conditions of those materials were investigated by transmission electron microscopy and energy dispersive x-ray spectroscopy. As a result, (1) IGSCC crack growth was observed on non sensitized and cold worked SUS316 under deaerated and 0.3 ppm hydrogenated water environments at 320degC; (2) Any trace of IGSCC crack growth was not observed on sensitized at 650degC for 48 hours and cold worked SUS316 under the same water environments; (3) The SUS316 sensitized at 650degC for 48 hours showed extensive M 23 C 6 precipitation as well as Cr depletion at grain boundaries. These differences in IGSCC crack growth rate indicate that grain boundary carbide has the beneficial effect of improving IGSCC susceptibility, at least under deaerated and 0.3 ppm hydrogenated water environments, despite chromium depletion at the grain boundary. (author)

  3. High Definition Clouds and Precipitation for advancing Climate Prediction (HD(CP)2): Large Eddy Simulation Study Over Germany

    Science.gov (United States)

    Dipankar, A.; Stevens, B. B.; Zängl, G.; Pondkule, M.; Brdar, S.

    2014-12-01

    The effect of clouds on large scale dynamics is represented in climate models through parameterization of various processes, of which the parameterization of shallow and deep convection are particularly uncertain. The atmospheric boundary layer, which controls the coupling to the surface, and which defines the scale of shallow convection, is typically 1 km in depth. Thus, simulations on a O(100 m) grid largely obviate the need for such parameterizations. By crossing this threshold of O(100m) grid resolution one can begin thinking of large-eddy simulation (LES), wherein the sub-grid scale parameterization have a sounder theoretical foundation. Substantial initiatives have been taken internationally to approach this threshold. For example, Miura et al., 2007 and Mirakawa et al., 2014 approach this threshold by doing global simulations, with (gradually) decreasing grid resolution, to understand the effect of cloud-resolving scales on the general circulation. Our strategy, on the other hand, is to take a big leap forward by fixing the resolution at O(100 m), and gradually increasing the domain size. We believe that breaking this threshold would greatly help in improving the parameterization schemes and reducing the uncertainty in climate predictions. To take this forward, the German Federal Ministry of Education and Research has initiated a project on HD(CP)2 that aims for a limited area LES at resolution O(100 m) using the new unified modeling system ICON (Zängl et al., 2014). In the talk, results from the HD(CP)2 evaluation simulation will be shown that targets high resolution simulation over a small domain around Jülich, Germany. This site is chosen because high resolution HD(CP)2 Observational Prototype Experiment took place in this region from 1.04.2013 to 31.05.2013, in order to critically evaluate the model. Nesting capabilities of ICON is used to gradually increase the resolution from the outermost domain, which is forced from the COSMO-DE data, to the

  4. Theory and uses of electrostatic precipitators

    Energy Technology Data Exchange (ETDEWEB)

    Descolas, M

    1974-01-01

    Factors influencing the efficiency of electrostatic precipitators, and the principal uses of this type of dust separator are reviewed. The counter-ionization caused by very high resistivity of the dust can be avoided theoretically by increasing the temperature. The resistance of the settled dust layer is determined not only by the inherent resistivity of the dust but also that of impurities adsorbed by the dust particles, such as water vapor and sulfur dioxide, which tend to decrease the resistance. The maximum possible current intensity decreases with increasing temperature. The current intensity decreases with increasing dust concentration in the waste gas. Electrostatic dust precipitators are successfully used in thermal power plants, waste incinerators, open-hearth furnaces, and oxygen converters. In the pulp industry, they are used to recover sodium sulfate and carbonate between the soda lye boiler and the economizer.

  5. The hydrological cycle in the high Pamir Mountains: how temperature and seasonal precipitation distribution influence stream flow in the Gunt catchment, Tajikistan

    Science.gov (United States)

    Pohl, E.; Knoche, M.; Gloaguen, R.; Andermann, C.; Krause, P.

    2014-12-01

    Complex climatic interactions control hydrological processes in high mountains that in their turn regulate the erosive forces shaping the relief. To unravel the hydrological cycle of a glaciated watershed (Gunt River) considered representative of the Pamirs' hydrologic regime we developed a remote sensing-based approach. At the boundary between two distinct climatic zones dominated by Westerlies and Indian summer monsoon, the Pamir is poorly instrumented and only a few in situ meteorological and hydrological data are available. We adapted a suitable conceptual distributed hydrological model (J2000g). Interpolations of the few available in situ data are inadequate due to strong, relief induced, spatial heterogeneities. Instead we use raster data, preferably from remote sensing sources depending on availability and validation. We evaluate remote sensing-based precipitation and temperature products. MODIS MOD11 surface temperatures show good agreement with in situ data, perform better than other products and represent a good proxy for air temperatures. For precipitation we tested remote sensing products as well as the HAR10 climate model data and the interpolation-based APHRODITE dataset. All products show substantial differences both in intensity and seasonal distribution with in-situ data. Despite low resolutions, the datasets are able to sustain high model efficiencies (NSE ≥0.85). In contrast to neighbouring regions in the Himalayas or the Hindukush, discharge is dominantly the product of snow and glacier melt and thus temperature is the essential controlling factor. 80% of annual precipitation is provided as snow in winter and spring contrasting peak discharges during summer. Hence, precipitation and discharge are negatively correlated and display complex hysteresis effects that allow to infer the effect of inter-annual climatic variability on river flow. We infer the existence of two subsurface reservoirs. The groundwater reservoir (providing 40% of annual

  6. Precipitation Sedimentation and Advection in GFS

    Science.gov (United States)

    Sun, R.; Tallapragada, V.

    2016-12-01

    Zhao and Carr microphysics scheme as implemented in the NCEP Global Forecasting System (GFS) predicts only the total cloud condensate (cloud water or ice). The precipitation generated in the column fall to the ground instantly. This mean precipitation sedimentation and advection are not considered. As resolution increases the lack of the two physical processes creates problems. The slowly falling precipitation (snow) falls to the wrong surface grid box, which may have led to the observed spotty-precipitation pattern. To solve the problem two prognositic variables, snow and rain, are added. Addition of the two precipitation variable allows their advection. The corresponding sedimentation process are also added. In this study we examine the effect of precipitation advection and sedimentation on the precipitation pattern, associated precipitation skills and clouds.

  7. Aluminum precipitation from Hanford DSSF

    International Nuclear Information System (INIS)

    Borgen, D.; Frazier, P.; Staton, G.

    1994-01-01

    A series of pilot scale tests using simulated Double Shell Slurry Feed (DSSF) showed that well-settled aluminum precipitate can be produced in Hanford double shell tank (DST) high level waste by slow neutralization with carbon dioxide. This pretreatment could provide an early grout feed and free tank space, as well as facilitate downstream processes such as ion exchange by providing a less caustic feed. A total of eight test runs were completed using a 10-ft tall 3-in i.d. glass column. The 10-ft height corresponds to about one third of the vertical height of a DST, hence providing a reasonable basis for extrapolating the observed precipitate settling and compaction to the actual waste tank environment. Four runs (three with a simplified simulant and one with a chemically complete simulant) produced well settled precipitates averaging 1.5 to 2 feet high. Aluminum gel rather than settled precipitate resulted from one test where neutralization was too rapid

  8. Do rising temperatures always increase forest productivity? Interacting effects of temperature, precipitation, cloudiness and soil texture on tree species growth and competition

    Science.gov (United States)

    Eric J. Gustafson; Brian R. Miranda; Arjan M.G. De Bruijn; Brian R. Sturtevant; Mark E. Kubiske

    2017-01-01

    Forest landscape models (FLM) are increasingly used to project the effects of climate change on forested landscapes, yet most use phenomenological approaches with untested assumptions about future forest dynamics. We used a FLM that relies on first principles to mechanistically simulate growth (LANDIS-II with PnET-Succession) to systematically explore how landscapes...

  9. Tensile behavior of Cu50Zr50 metallic glass nanowire with a B2 crystalline precipitate

    Science.gov (United States)

    Sepulveda-Macias, Matias; Amigo, Nicolas; Gutierrez, Gonzalo

    2018-02-01

    A molecular dynamics study of the effect of a single B2-CuZr precipitate on the mechanical properties of Cu50Zr50 metallic glass nanowires is presented. Four different samples are considered: three with a 2, 4 and 6 nm radii precipitate and a precipitate-free sample. These systems are submitted to uniaxial tensile test up to 25% of strain. The interface region between the precipitate and the glass matrix has high local atomic shear strain, activating shear transformation zones, which concentrates in the neighborhood of the precipitate. The plastic regime is dominated by necking, and no localized shear band is observed for the samples with a 4 and 6 nm radii precipitate. In addition, the yield stress decreases as the size of the precipitate increases. Regarding the precipitate structure, no martensitic phase transformation is observed, since neither the shear band hit the precipitate nor the stress provided by the tensile test is enough to initiate the transformation. It is concluded that, in contrast to the case when multiple precipitates are present in the sample, a single precipitate concentrates the shear strain around its surface, eventually causing the failure of the nanowire.

  10. Predicting when precipitation-driven synthesis is feasible : application to biocatalysis

    NARCIS (Netherlands)

    Ulijn, R.V.; Janssen, A.E.M.; Moore, B.D.; Halling, P.J.

    2001-01-01

    Precipitation-driven synthesis offers the possibility of obtaining high reaction yields using very low volume reactors and is finding increasing applications in biocatalysis. Here, a model that allows straightforward prediction of when such a precipitation-driven reaction will be thermodynamically

  11. On the Precipitation and Precipitation Change in Alaska

    Directory of Open Access Journals (Sweden)

    Gerd Wendler

    2017-12-01

    Full Text Available Alaska observes very large differences in precipitation throughout the state; southeast Alaska experiences consistently wet conditions, while northern Arctic Alaska observes very dry conditions. The maximum mean annual precipitation of 5727 mm is observed in the southeastern panhandle at Little Port Arthur, while the minimum of 92 mm occurs on the North Slope at Kuparuk. Besides explaining these large differences due to geographic and orographic location, we discuss the changes in precipitation with time. Analyzing the 18 first-order National Weather Service stations, we found that the total average precipitation in the state increased by 17% over the last 67 years. The observed changes in precipitation are furthermore discussed as a function of the observed temperature increase of 2.1 °C, the mean temperature change of the 18 stations over the same period. This observed warming of Alaska is about three times the magnitude of the mean global warming and allows the air to hold more water vapor. Furthermore, we discuss the effect of the Pacific Decadal Oscillation (PDO, which has a strong influence on both the temperature and precipitation in Alaska.

  12. Denitration and chemical precipitation of medium level liquid wastes and conditioning of high level wastes from low level liquid wastes by a roll dryer and subsequent vitrification

    International Nuclear Information System (INIS)

    Halaszovich, S.; Dix, S.; Harms, R.

    1987-01-01

    Medium level liquid waste (MAW) from the reprocessing need after being fixed in cement an additional shielding to meet required radiation limits for handling and transportation. Normally this shielding consists of concrete and its weight and volume is several times higher than that of the waste product itself. By means of caesium separation using nickel-potassium-hexacyanoferrate and after few years of interim storage waiting for the decay of Ruthenium and Antimony the activities will be reduced below permissible values. (13 MBq/l in waste solution for Cs, 28 MBq/l for Sb and 34 MBq/l for Ru). Below these limits there is no need for additional shielding after cementation in a 400 l drum. Experimental results show, that Caesium can be precipitated and separated effectively not only in laboratory but also in a larger scale under hot cell conditions. The process investigated in this work has been developed from the FIPS process for vitrification of highly radioactive fission product solutions. It consists of: denitration, precipitation, sludge separation, drying and melting

  13. Coupled atmosphere ocean climate model simulations in the Mediterranean region: effect of a high-resolution marine model on cyclones and precipitation

    Directory of Open Access Journals (Sweden)

    A. Sanna

    2013-06-01

    Full Text Available In this study we investigate the importance of an eddy-permitting Mediterranean Sea circulation model on the simulation of atmospheric cyclones and precipitation in a climate model. This is done by analyzing results of two fully coupled GCM (general circulation models simulations, differing only for the presence/absence of an interactive marine module, at very high-resolution (~ 1/16°, for the simulation of the 3-D circulation of the Mediterranean Sea. Cyclones are tracked by applying an objective Lagrangian algorithm to the MSLP (mean sea level pressure field. On annual basis, we find a statistically significant difference in vast cyclogenesis regions (northern Adriatic, Sirte Gulf, Aegean Sea and southern Turkey and in lifetime, giving evidence of the effect of both land–sea contrast and surface heat flux intensity and spatial distribution on cyclone characteristics. Moreover, annual mean convective precipitation changes significantly in the two model climatologies as a consequence of differences in both air–sea interaction strength and frequency of cyclogenesis in the two analyzed simulations.

  14. A high dietary glycemic index increases total mortality in a Mediterranean population at high cardiovascular risk.

    Directory of Open Access Journals (Sweden)

    Itandehui Castro-Quezada

    Full Text Available OBJECTIVE: Different types of carbohydrates have diverse glycemic response, thus glycemic index (GI and glycemic load (GL are used to assess this variation. The impact of dietary GI and GL in all-cause mortality is unknown. The objective of this study was to estimate the association between dietary GI and GL and risk of all-cause mortality in the PREDIMED study. MATERIAL AND METHODS: The PREDIMED study is a randomized nutritional intervention trial for primary cardiovascular prevention based on community-dwelling men and women at high risk of cardiovascular disease. Dietary information was collected at baseline and yearly using a validated 137-item food frequency questionnaire (FFQ. We assigned GI values of each item by a 5-step methodology, using the International Tables of GI and GL Values. Deaths were ascertained through contact with families and general practitioners, review of medical records and consultation of the National Death Index. Cox regression models were used to estimate multivariable-adjusted hazard ratios (HR and their 95% CI for mortality, according to quartiles of energy-adjusted dietary GI/GL. To assess repeated measures of exposure, we updated GI and GL intakes from the yearly FFQs and used Cox models with time-dependent exposures. RESULTS: We followed 3,583 non-diabetic subjects (4.7 years of follow-up, 123 deaths. As compared to participants in the lowest quartile of baseline dietary GI, those in the highest quartile showed an increased risk of all-cause mortality [HR = 2.15 (95% CI: 1.15-4.04; P for trend  = 0.012]. In the repeated-measures analyses using as exposure the yearly updated information on GI, we observed a similar association. Dietary GL was associated with all-cause mortality only when subjects were younger than 75 years. CONCLUSIONS: High dietary GI was positively associated with all-cause mortality in elderly population at high cardiovascular risk.

  15. Characteristics and seasonal variations of precipitation phenomena at Syowa Station

    Directory of Open Access Journals (Sweden)

    Hiroyuki Konishi

    1997-03-01

    Full Text Available Long-term observations of precipitating clouds were carried out by a vertical pointing radar, PPI radar and a 37 GHz microwave radiometer at Syowa Station (69°00′S, 39°35′E, Antarctica in 1989. It is concluded from the observations that precipitation near Syowa Station, Antarctica is mainly brought by cloud vortices associated with extratropical cyclones which advance to high latitude while developing to a mature stage. The seasonal variations of clouds and precipitation were analyzed corresponding to the seasonal changes of air temperature and sea ice area. The occurrence frequencies of cloud vortices which brought snowfall to Syowa Station increased in the fall and spring seasons corresponding to activity of the circumpolar trough. However, the activities of cloud systems that bring precipitation weaken in spring when the sea ice area expands to low latitudes, because of less supply of heat and vapor. In 1989,the amount of precipitation in spring brought by a few snowfall events was as large as the amount of precipitation in fall brought by frequent snowfall events. Radar observations revealed that there were three abundant snowfall seasons at Syowa Station and the amount of snowfall was uniform in all seasons except summer. The amounts of precipitation in fall, winter and spring were 74,74 and 53mm respectively.

  16. Evaluation of precipitates used in strainer head loss testing. Part I. Chemically generated precipitates

    International Nuclear Information System (INIS)

    Bahn, Chi Bum; Kasza, Ken E.; Shack, William J.; Natesan, Ken; Klein, Paul

    2009-01-01

    The purpose of the current program was to evaluate the properties of chemical precipitates proposed by industry that have been used in sump strainer head loss testing. Specific precipitates that were evaluated included aluminum oxyhydroxide (AlOOH) and sodium aluminum silicate (SAS) prepared according to the procedures in WCAP-16530-NP, along with precipitates formed from injecting chemicals into the test loop according to the procedure used by one sump strainer test vendor for U.S. pressurized water reactors. The settling rates of the surrogate precipitates are strongly dependent on their particle size and are reasonably consistent with those expected from Stokes' Law or colloid aggregation models. Head loss tests showed that AlOOH and SAS surrogates are quite effective in increasing the head loss across a perforated pump inlet strainer that has an accumulated fibrous debris bed. The characteristics of aluminum hydroxide precipitate using sodium aluminate were dependent on whether it was formed in high-purity or ordinary tap water and whether excess silicate was present or not.

  17. Spatial analysis of precipitation time series over the Upper Indus Basin

    Science.gov (United States)

    Latif, Yasir; Yaoming, Ma; Yaseen, Muhammad

    2018-01-01

    The upper Indus basin (UIB) holds one of the most substantial river systems in the world, contributing roughly half of the available surface water in Pakistan. This water provides necessary support for agriculture, domestic consumption, and hydropower generation; all critical for a stable economy in Pakistan. This study has identified trends, analyzed variability, and assessed changes in both annual and seasonal precipitation during four time series, identified herein as: (first) 1961-2013, (second) 1971-2013, (third) 1981-2013, and (fourth) 1991-2013, over the UIB. This study investigated spatial characteristics of the precipitation time series over 15 weather stations and provides strong evidence of annual precipitation by determining significant trends at 6 stations (Astore, Chilas, Dir, Drosh, Gupis, and Kakul) out of the 15 studied stations, revealing a significant negative trend during the fourth time series. Our study also showed significantly increased precipitation at Bunji, Chitral, and Skardu, whereas such trends at the rest of the stations appear insignificant. Moreover, our study found that seasonal precipitation decreased at some locations (at a high level of significance), as well as periods of scarce precipitation during all four seasons. The observed decreases in precipitation appear stronger and more significant in autumn; having 10 stations exhibiting decreasing precipitation during the fourth time series, with respect to time and space. Furthermore, the observed decreases in precipitation appear robust and more significant for regions at high elevation (>1300 m). This analysis concludes that decreasing precipitation dominated the UIB, both temporally and spatially including in the higher areas.

  18. Intercomparison of spaceborne precipitation radars and its applications in examining precipitation-topography relationships in the Tibetan Plateau

    Science.gov (United States)

    Tang, G.; Gao, J.; Long, D.

    2017-12-01

    Precipitation is one of the most important components in the water and energy cycles. Spaceborne radars are considered the most direct technology for observing precipitation from space since 1998. This study compares and evaluates the only three existing spaceborne precipitation radars, i.e., the Ku-band precipitation radar (TRMM PR), the W-band Cloud Profiling Radar (CloudSat CPR), and the Ku/Ka-band Dual-frequency Precipitation Radar (GPM DPR). In addition, TRMM PR and GPM DPR are evaluated against hourly rain gauge data in Mainland China. The Tibetan Plateau (TP) is known as the Earth's third pole where precipitation is affected profoundly by topography. However, ground gauges are extremely sparse in the TP, and spaceborne radars can provide valuable data with relatively high accuracy. The relationships between precipitation and topography over the TP are investigated using 17-year TRMM PR data and 2-year GPM DPR data, in combination with rain gauge data. Results indicate that: (1) DPR and PR agree with each other and correlate very well with gauges in Mainland China. DPR improves light precipitation detectability significantly compared with PR. However, DPR high sensitivity scans (HS) deviates from DPR normal and matched scans (NS and MS) and PR in the comparison based on global coincident events and rain gauges in China; (2) CPR outperforms the other two radars in terms of light precipitation detection. In terms of global snowfall estimation, DPR and CPR show very different global snowfall distributions originating from different frequencies, retrieval algorithms, and sampling characteristics; and (3) Precipitation generally decreases exponentially with increasing elevation in the TP. The precipitation-topography relationships are regressed using exponential fitting in seventeen river basins in the TP with good coefficients of determination. Due to the short time span of GPM DPR, the relationships based on GPM DPR data are less robust than those derived from

  19. Carbon redistribution and precipitation in high temperature ion-implanted strained Si/SiGe/Si multi-layered structures

    DEFF Research Database (Denmark)

    Gaiduk, Peter; Hansen, John Lundsgaard; Nylandsted Larsen, Arne

    2014-01-01

    Graphical abstract Carbon depth profiles after high temperature implantation in strained Si/SiGe/Si multilayered system and induced structural defects.......Graphical abstract Carbon depth profiles after high temperature implantation in strained Si/SiGe/Si multilayered system and induced structural defects....

  20. Intensification of extreme European summer precipitation in a warmer climate

    DEFF Research Database (Denmark)

    Christensen, O. B.; Christensen, J. H.

    2004-01-01

    Heavy and/or extended precipitation episodes with subsequent surface runoff can inflict catastrophic property damage and loss of human life. Thus, it is important to determine how the character of such events could change in response to greenhouse gas-induced global warming. Impacts of climate...... warming on severe precipitation events in Europe on a diurnal time scale were investigated with a high-resolution regional climate model for two of the greenhouse gas emission scenarios constructed by the Intergovernmental Panel on Climate Change (IPCC; Nakicenovic, N., et al., 2000, IPCC special report...... models both originating from fully transient climate change simulations. Here, we show that although the summer time precipitation decreases over a substantial part of Europe in the scenarios analysed, an increase in the amount of precipitation exceeding the present-day 99th and in most cases even the 95...

  1. A global satellite assisted precipitation climatology

    Science.gov (United States)

    Funk, Christopher C.; Verdin, Andrew P.; Michaelsen, Joel C.; Pedreros, Diego; Husak, Gregory J.; Peterson, P.

    2015-01-01

    Accurate representations of mean climate conditions, especially in areas of complex terrain, are an important part of environmental monitoring systems. As high-resolution satellite monitoring information accumulates with the passage of time, it can be increasingly useful in efforts to better characterize the earth's mean climatology. Current state-of-the-science products rely on complex and sometimes unreliable relationships between elevation and station-based precipitation records, which can result in poor performance in food and water insecure regions with sparse observation networks. These vulnerable areas (like Ethiopia, Afghanistan, or Haiti) are often the critical regions for humanitarian drought monitoring. Here, we show that long period of record geo-synchronous and polar-orbiting satellite observations provide a unique new resource for producing high resolution (0.05°) global precipitation climatologies that perform reasonably well in data sparse regions. Traditionally, global climatologies have been produced by combining station observations and physiographic predictors like latitude, longitude, elevation, and slope. While such approaches can work well, especially in areas with reasonably dense observation networks, the fundamental relationship between physiographic variables and the target climate variables can often be indirect and spatially complex. Infrared and microwave satellite observations, on the other hand, directly monitor the earth's energy emissions. These emissions often correspond physically with the location and intensity of precipitation. We show that these relationships provide a good basis for building global climatologies. We also introduce a new geospatial modeling approach based on moving window regressions and inverse distance weighting interpolation. This approach combines satellite fields, gridded physiographic indicators, and in situ climate normals. The resulting global 0.05° monthly precipitation climatology, the Climate

  2. Can the water content of highly compacted bentonite be increased by applying a high water pressure?

    International Nuclear Information System (INIS)

    Pusch, R.; Kasbohm, J.

    2001-10-01

    A great many laboratory investigations have shown that the water uptake in highly compacted MX-80 clay takes place by diffusion at low external pressure. It means that wetting of the clay buffer in the deposition holes of a KBS-3 repository is very slow if the water pressure is low and that complete water saturation can take several tens of years if the initial degree of water saturation of the buffer clay and the ability of the rock to give off water are low. It has therefore been asked whether injection of water can raise the degree of water saturation and if a high water pressure in the nearfield can have the same effect. The present report describes attempts to moisten highly compacted blocks of MX-80 clay with a dry density of 1510 kg/m 3 by injecting water under a pressure of 650 kPa through a perforated injection pipe for 3 and 20 minutes, respectively. The interpretation was made by determining the water content of a number of samples located at different distances from the pipe. An attempt to interpret the pattern of distribution of injected uranium acetate solution showed that the channels into which the solution went became closed in a few minutes and that dispersion in the homogenized clay gave low U-concentrations. The result was that the water content increased from about 9 to about 11-12 % within a distance of about 1 centimeter from the injection pipe and to slightly more than 9 % at a distance of about 4-5 cm almost independently of the injection time. Complete water saturation corresponds to a water content of about 30 % and the wetting effect was hence small from a practical point of view. By use of microstructural models it can be shown that injected water enters only the widest channels that remain after the compaction and that these channels are quickly closed by expansion of the hydrating surrounding clay. Part of the particles that are thereby released become transported by the flowing water and cause clogging of the channels, which is

  3. Asymmetric responses of primary productivity to precipitation extremes: A synthesis of grassland precipitation manipulation experiments.

    Science.gov (United States)

    Wilcox, Kevin R; Shi, Zheng; Gherardi, Laureano A; Lemoine, Nathan P; Koerner, Sally E; Hoover, David L; Bork, Edward; Byrne, Kerry M; Cahill, James; Collins, Scott L; Evans, Sarah; Gilgen, Anna K; Holub, Petr; Jiang, Lifen; Knapp, Alan K; LeCain, Daniel; Liang, Junyi; Garcia-Palacios, Pablo; Peñuelas, Josep; Pockman, William T; Smith, Melinda D; Sun, Shanghua; White, Shannon R; Yahdjian, Laura; Zhu, Kai; Luo, Yiqi

    2017-10-01

    Climatic changes are altering Earth's hydrological cycle, resulting in altered precipitation amounts, increased interannual variability of precipitation, and more frequent extreme precipitation events. These trends will likely continue into the future, having substantial impacts on net primary productivity (NPP) and associated ecosystem services such as food production and carbon sequestration. Frequently, experimental manipulations of precipitation have linked altered precipitation regimes to changes in NPP. Yet, findings have been diverse and substantial uncertainty still surrounds generalities describing patterns of ecosystem sensitivity to altered precipitation. Additionally, we do not know whether previously observed correlations between NPP and precipitation remain accurate when precipitation changes become extreme. We synthesized results from 83 case studies of experimental precipitation manipulations in grasslands worldwide. We used meta-analytical techniques to search for generalities and asymmetries of aboveground NPP (ANPP) and belowground NPP (BNPP) responses to both the direction and magnitude of precipitation change. Sensitivity (i.e., productivity response standardized by the amount of precipitation change) of BNPP was similar under precipitation additions and reductions, but ANPP was more sensitive to precipitation additions than reductions; this was especially evident in drier ecosystems. Additionally, overall relationships between the magnitude of productivity responses and the magnitude of precipitation change were saturating in form. The saturating form of this relationship was likely driven by ANPP responses to very extreme precipitation increases, although there were limited studies imposing extreme precipitation change, and there was considerable variation among experiments. This highlights the importance of incorporating gradients of manipulations, ranging from extreme drought to extreme precipitation increases into future climate change

  4. Neutral escape at Mars induced by the precipitation of high-energy protons and hydrogen atoms of the solar wind origin

    Science.gov (United States)

    Shematovich, Valery I.

    2017-04-01

    One of the first surprises of the NASA MAVEN mission was the observation by the SWIA instrument of a tenuous population of protons with solar wind energies travelling anti-sunward near periapsis, at altitudes of 150-250 km (Halekas et al., 2015). While the penetration of solar wind protons to low altitude is not completely unexpected given previous Mars Express results, this population maintains exactly the same velocity as the solar wind observed. From previous studies it was known that some fraction of the solar wind can interact with the extended corona of Mars. By charge exchange with the neutral particles in this corona, some fraction of the incoming solar wind protons can gain an electron and become an energetic neutral hydrogen atom. Once neutral, these particles penetrate through the Martian induced magnetosphere with ease, with free access to the collisional atmosphere/ionosphere. The origin, kinetics and transport of the suprathermal O atoms in the transition region (from thermosphere to exosphere) of the Martian upper atmosphere due to the precipitation of the high-energy protons and hydrogen atoms are discussed. Kinetic energy distribution functions of suprathermal and superthermal (ENA) oxygen atoms formed in the Martian upper atmosphere were calculated using the kinetic Monte Carlo model (Shematovich et al., 2011, Shematovich, 2013) of the high-energy proton and hydrogen atom precipitation into the atmosphere. These functions allowed us: (a) to estimate the non-thermal escape rates of neutral oxygen from the Martian upper atmosphere, and (b) to compare with available MAVEN measurements of oxygen corona. Induced by precipitation the escape of hot oxygen atoms may become dominant under conditions of extreme solar events - solar flares and coronal mass ejections, - as it was shown by recent observations of the NASA MAVEN spacecraft (Jakosky et al., 2015). This work is supported by the RFBR project and by the Basic Research Program of the Praesidium of

  5. Changes in precipitation extremes projected by a 20-km mesh global atmospheric model

    Directory of Open Access Journals (Sweden)

    Akio Kitoh

    2016-03-01

    Full Text Available High-resolution modeling is necessary to project weather and climate extremes and their future changes under global warming. A global high-resolution atmospheric general circulation model with grid size about 20 km is able to reproduce climate fields as well as regional-scale phenomena such as monsoonal rainfall, tropical and extratropical cyclones, and heavy precipitation. This 20-km mesh model is applied to project future changes in weather and climate extremes at the end of the 21st century with four different spatial patterns in sea surface temperature (SST changes: one with the mean SST changes by the 28 models of the Coupled Model Intercomparison Project Phase 5 (CMIP5 under the Representative Concentration Pathways (RCP-8.5 scenario, and the other three obtained from a cluster analysis, in which tropical SST anomalies derived from the 28 CMIP5 models were grouped. Here we focus on future changes in regional precipitation and its extremes. Various precipitation indices averaged over the Twenty-two regional land domains are calculated. Heavy precipitation indices (maximum 5-day precipitation total and maximum 1-day precipitation total increase in all regional domains, even where mean precipitation decrease (Southern Africa, South Europe/Mediterranean, Central America. South Asia is the domain of the largest extreme precipitation increase. In some domains, different SST patterns result in large precipitation changes, possibly related to changes in large-scale circulations in the tropical Pacific.

  6. Cultivar by environment effects of perennial ryegrass cultivars selected for high water soluble carbohydrates managed under differing precipitation levels

    Science.gov (United States)

    Historic results of perennial ryegrass (Lolium perenne L.) breeding include improved disease resistance, biomass, and nutritional quality. Yet, lack of tolerance to water stress limits its wise use. Recent efforts to increase water soluble carbohydrate (WSC) content in perennial ryegrass may incre...

  7. Modelled Precipitation Over Greenland

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes the annual total precipitation from 1985 to 1999 and monthly total precipitation from January 1985 to December 1999. The data is derived from...

  8. Dynamical response of Mediterranean precipitation to greenhouse gases and aerosols

    Directory of Open Access Journals (Sweden)

    T. Tang

    2018-06-01

    Full Text Available Atmospheric aerosols and greenhouse gases affect cloud properties, radiative balance and, thus, the hydrological cycle. Observations show that precipitation has decreased in the Mediterranean since the beginning of the 20th century, and many studies have investigated possible mechanisms. So far, however, the effects of aerosol forcing on Mediterranean precipitation remain largely unknown. Here we compare the modeled dynamical response of Mediterranean precipitation to individual forcing agents in a set of global climate models (GCMs. Our analyses show that both greenhouse gases and aerosols can cause drying in the Mediterranean and that precipitation is more sensitive to black carbon (BC forcing than to well-mixed greenhouse gases (WMGHGs or sulfate aerosol. In addition to local heating, BC appears to reduce precipitation by causing an enhanced positive sea level pressure (SLP pattern similar to the North Atlantic Oscillation–Arctic Oscillation, characterized by higher SLP at midlatitudes and lower SLP at high latitudes. WMGHGs cause a similar SLP change, and both are associated with a northward diversion of the jet stream and storm tracks, reducing precipitation in the Mediterranean while increasing precipitation in northern Europe. Though the applied forcings were much larger, if forcings are scaled to those of the historical period of 1901–2010, roughly one-third (31±17 % of the precipitation decrease would be attributable to global BC forcing with the remainder largely attributable to WMGHGs, whereas global scattering sulfate aerosols would have negligible impacts. Aerosol–cloud interactions appear to have minimal impacts on Mediterranean precipitation in these models, at least in part because many simulations did not fully include such processes; these merit further study. The findings from this study suggest that future BC and WMGHG emissions may significantly affect regional water resources, agricultural practices, ecosystems and

  9. Formation and Thermal Stability of Large Precipitates and Oxides in Titanium and Niobium Microalloyed Steel

    Institute of Scientific and Technical Information of China (English)

    ZHUO Xiao-jun; WOO Dae-hee; WANG Xin-hua; LEE Hae-geon

    2008-01-01

    As-cast CC slabs of microalloyed steels are prone to surface and sub-surface cracking. Precipitation phenomena in-itiated during solidification reduce ductility at high temperature. The unidirectional solidification unit is employed to sim-ulate the solidification process during continuous casting. Precipitation behavior and thermal stability are systemati-cally investigated. Samples of adding titanium and niobium to steels have been examined using field emission scanning electron microscope (FE-SEM), electron probe X-ray microanalyzer (EPMA), and transmission electron microscope (TEM). It has been found that the addition of titanium and niobium to high-strength low-alloyed (HSLA) steel resuited in undesirable large precipitation in the steels, i. e. , precipitation of large precipitates with various morphologies. The composition of the large precipitates has been determined. The effect of cooling rate on (Ti, Nb)(C, N) precipitate formation is investigated. With increasing the cooling rate, titanium-rich (Ti,Nb)(C, N) precipitates are transformed to niobium-rich (Ti,Nb)(C,N) precipitates. The thermal stability of these large precipitates and oxides have been assessed by carrying out various heat treatments such as holding and quenching from temperature at 800 and 1 200 ℃. It has been found that titanium-rich (Ti,Nb)(C,N) precipitate is stable at about 1 200 ℃ and niobi-um-rich (Ti,Nb)(C,N) precipitate is stable at about 800 ℃. After reheating at 1 200 ℃ for 1 h, (Ca, Mn)S and TiN are precipitated from Ca-Al oxide. However, during reheating at 800 ℃ for 1 h, Ca-Al-Ti oxide in specimens was stable. The thermodynamic calculation of simulating the thermal process is employed. The calculation results are in good agreement with the experimental results.

  10. Long-Term Quantitative Precipitation Estimates (QPE) at High Spatial and Temporal Resolution over CONUS: Bias-Adjustment of the Radar-Only National Mosaic and Multi-sensor QPE (NMQ/Q2) Precipitation Reanalysis (2001-2012)

    Science.gov (United States)

    Prat, Olivier; Nelson, Brian; Stevens, Scott; Seo, Dong-Jun; Kim, Beomgeun

    2015-04-01

    The processing of radar-only precipitation via the reanalysis from the National Mosaic and Multi-Sensor Quantitative (NMQ/Q2) based on the WSR-88D Next-generation Radar (NEXRAD) network over Continental United States (CONUS) is completed for the period covering from 2001 to 2012. This important milestone constitutes a unique opportunity to study precipitation processes at a 1-km spatial resolution for a 5-min temporal resolution. However, in order to be suitable for hydrological, meteorological and climatological applications, the radar-only product needs to be bias-adjusted and merged with in-situ rain gauge information. Several in-situ datasets are available to assess the biases of the radar-only product and to adjust for those biases to provide a multi-sensor QPE. The rain gauge networks that are used such as the Global Historical Climatology Network-Daily (GHCN-D), the Hydrometeorological Automated Data System (HADS), the Automated Surface Observing Systems (ASOS), and the Climate Reference Network (CRN), have different spatial density and temporal resolution. The challenges related to incorporating non-homogeneous networks over a vast area and for a long-term record are enormous. Among the challenges we are facing are the difficulties incorporating differing resolution and quality surface measurements to adjust gridded estimates of precipitation. Another challenge is the type of adjustment technique. The objective of this work is threefold. First, we investigate how the different in-situ networks can impact the precipitation estimates as a function of the spatial density, sensor type, and temporal resolution. Second, we assess conditional and un-conditional biases of the radar-only QPE for various time scales (daily, hourly, 5-min) using in-situ precipitation observations. Finally, after assessing the bias and applying reduction or elimination techniques, we are using a unique in-situ dataset merging the different RG networks (CRN, ASOS, HADS, GHCN-D) to

  11. Preparation of nano-porous LiNi0.5Mn1.5O4 with high electrochemical performances by a co-precipitation method for 5 V lithium-ion batteries

    Science.gov (United States)

    Cui, Xiaoling; Li, Hongliang; Li, Shiyou

    2017-10-01

    Porous LiNi0.5Mn1.5O4 is prepared by co-precipitation method. The results of scanning electron microscopy show that the sample has a nano-porous structure. Charge-discharge tests show that the synthesized product exhibits excellent electrochemical performance with a high initial discharge capacity of 129.1 mAh g-1 at 0.5 C and a preferably capacity retention of 96.5% after 200 cycles. The superior performance of the synthesized product is attributed to its nano-porous structure. The nanoparticle reduces the path of Li+ diffusion and increases the reaction sites for lithium insertion/extraction, the pores provide room to buffer the volume changes during charge-discharge.

  12. Conditions for precipitation of copper phases in DWPF waste glass

    International Nuclear Information System (INIS)

    Schumacher, R.F.; Ramsey, W.G.

    1993-01-01

    The Defense Waste Processing Facility (DWPF) precipitate hydrolysis process requires the use of copper formate catalyst. The expected absorbed radiation doses to the precipitate require levels of copper formate that increase the potential for the precipitation of metallic copper in the DWPF Melter. The conditions required to avoid the precipitation of copper are described

  13. Precipitation Indices Low Countries

    Science.gov (United States)

    van Engelen, A. F. V.; Ynsen, F.; Buisman, J.; van der Schrier, G.

    2009-09-01

    (+2): Wide scale river flooding, marshy acres and meadows.-Farmers cope with poor harvests of hay, grains, fruit etc. resulting in famines.-Late grape harvests, poor yield quantity and quality of wine. Wet period (+1): High water levels cq discharges of major rivers, tributaries and brooks, local river floodings, marshy acres and meadows in the low lying areas.-Wearisome and hampered agriculture. Normal (0) Dry period (-1): Low water levels cq discharges of major rivers, tributaries and brooks. Some brooks may dry up.-Summer half year: local short of yield of grass, hay and other forage.-Summer half year: moor-, peat- and forest fires. Very dry period (-2): Very low water levels cq discharges of major rivers and tributaries. Brooks and wells dry up. Serious shortage of drinking water; especially in summer.-Major agricultural damage, shortage of water, mortality stock of cattle. Shortage of grain. Flour can not be produced due to water mills running out of water, shortage of bread, bread riots, famines.-Large scale forest and peat areas, resulting in serious air pollution. Town fires. By verifying the historical evidence on these criterions, a series of 5 step indices ranging from very dry to very wet for summer and winter half year of the Low Countries was obtained. Subsequently these indices series were compared with the instrumentally observed seasonal precipitation sums for De Bilt (1735-2008), which is considered to be representative for the Central Netherlands. For winter (Oct-March) and summer half year (Apr.-Sept.) the accumulated precipitation amounts are calculated; these amounts are approximately normally distributed. Based on this distribution, the cumulative frequency distribution is calculated. By tabulating the number of summers in the pre-instrumental period 1201-1750 for each of the drought classes, a distribution is calculated which is then related to the modern accumulated precipitation distribution. Assuming that the accumulated precipitation amount

  14. Contrasting trait responses in plant communities to experimental and geographic variation in precipitation

    DEFF Research Database (Denmark)

    Sandel, Brody Steven; Goldstein, Leah; Kraft, Nathan

    2010-01-01

    Patterns of precipitation are likely to change significantly in the coming century, with important but poorly understood consequences for plant communities. Experimental and correlative studies may provide insight into expected changes, but little research has addressed the degree of concordance...... between these approaches. We synthesized results from four experimental water addition studies with a correlative analysis of community changes across a large natural precipitation gradient in the United States. We investigated whether community composition, summarized with plant functional traits......, responded similarly to increasing precipitation among studies and sites. In field experiments, increased precipitation favored species with small seed size,short leaf life span and high leaf nitrogen (N) concentration. However, with increasing precipitation along the natural gradient, community composition...

  15. Properties of Extreme Precipitation and Their Uncertainties in 3-year GPM Precipitation Radar Data

    Science.gov (United States)

    Liu, N.; Liu, C.

    2017-12-01

    Extreme high precipitation rates are often related to flash floods and have devastating impacts on human society and the environments. To better understand these rare events, 3-year Precipitation Features (PFs) are defined by grouping the contiguous areas with nonzero near-surface precipitation derived using Global Precipitation Measurement (GPM) Ku band Precipitation Radar (KuPR). The properties of PFs with extreme precipitation rates greater than 20, 50, 100 mm/hr, such as the geographical distribution, volumetric precipitation contribution, seasonal and diurnal variations, are examined. In addition to the large seasonal and regional variations, the rare extreme precipitation rates often have a larger contribution to the local total precipitation. Extreme precipitation rates occur more often over land than over ocean. The challenges in the retrieval of extreme precipitation might be from the attenuation correction and large uncertainties in the Z-R relationships from near-surface radar reflectivity to precipitation rates. These potential uncertainties are examined by using collocated ground based radar reflectivity and precipitation retrievals.

  16. Acid precipitation literature review

    Energy Technology Data Exchange (ETDEWEB)

    Seip, H M; Andersen, B; Andersson, G; Hov, Oe; Kucera, V; Moseholm, L

    1986-01-01

    There is an increasing number of publications on acid deposition and related phenomena. Interest in these topics has also been reflected in a considerable number of meetings and conferences in this field. The largest of these in 1985 was the ''International Symposium on Acidic Precipitation'' (Muskoka, Ontario). Most work so far has been carried out in North America and Europe. There is, however, an increasing interest in obtaining a better picture of sensitive areas and possible acidification in other parts of the world. Anthropogenic SO/sub 2/ emissions have been estimated to be (in TgSyr/sup -1/): 2.4 (Africa), 4.1 (South America), 0.7 (Ocenia), and 18.3 (Asia). The largest increase during the last decade has been in Asia. Based on Studies of precipitation in remote areas it has been suggested that the natural background concentration for sulphate in many areas should be about 6 ..mu..eq 1/sup -1/. A new study of sulphate and nitrate in Greenland snow showed that both ions increased by a factor of about 2 from 1895 to 1978. The concentrations of SO/sub 2/ at Norwegian rural sites show a decreasing trend since late 1970s, while concentrations of sulphate in air show no clear trend. More reliable models for transformation, transport and deposition of chemicals are being developed, including three-dimensional grid models to describe episodes of elevated pollution levels lasting for a few days. Model calculations indicate that control of hydrocarbon (HC) emissions is much more efficient in reducing the ozone level in southern Scandinavia in episodes influenced by long-range transported pollutants than NO/sub x/ control of combined NO/sub x/ and HC control. 36 refs. (EG).

  17. MicroRadarNet: A network of weather micro radars for the identification of local high resolution precipitation patterns

    Science.gov (United States)

    Turso, S.; Paolella, S.; Gabella, M.; Perona, G.

    2013-01-01

    In this paper, MicroRadarNet, a novel micro radar network for continuous, unattended meteorological monitoring is presented. Key aspects and constraints are introduced. Specific design strategies are highlighted, leading to the technological implementations of this wireless, low-cost, low power consumption sensor network. Raw spatial and temporal datasets are processed on-board in real-time, featuring a consistent evaluation of the signals from the sensors and optimizing the data loads to be transmitted. Network servers perform the final post-elaboration steps on the data streams coming from each unit. Final network products are meteorological mappings of weather events, monitored with high spatial and temporal resolution, and lastly served to the end user through any Web browser. This networked approach is shown to imply a sensible reduction of the overall operational costs, including management and maintenance aspects, if compared to the traditional long range monitoring strategy. Adoption of the TITAN storm identification and nowcasting engine is also here evaluated for in-loop integration within the MicroRadarNet data processing chain. A brief description of the engine workflow is provided, to present preliminary feasibility results and performance estimates. The outcomes were not so predictable, taking into account relevant operational differences between a Western Alps micro radar scenario and the long range radar context in the Denver region of Colorado. Finally, positive results from a set of case studies are discussed, motivating further refinements and integration activities.

  18. Effect of quenching rate on precipitation kinetics in AA2219 DC cast alloy

    Energy Technology Data Exchange (ETDEWEB)

    Elgallad, E.M., E-mail: eelgalla@uqac.ca; Zhang, Z.; Chen, X.-G.

    2017-06-01

    Slow quenching of direct chill (DC) cast aluminum ingot plates used in large mold applications is often used to decrease quench-induced residual stresses, which can deteriorate the machining performance of these plates. Slow quenching may negatively affect the mechanical properties of the cast plates when using highly quench-sensitive aluminum alloys because of its negative effect on the precipitation hardening behavior of such alloys. The effect of the quenching rate on precipitation kinetics in AA2219 DC cast alloy was systematically studied under water and air quenching conditions using differential scanning calorimetry (DSC) technique. Transmission electron microscopy (TEM) was also used to characterize the precipitate microstructure. The results showed that the precipitation kinetics of the θ′ phase in the air-quenched condition was mostly slower than that in the water-quenched one. Air quenching continuously increased the precipitation kinetics of the θ phase compared to water quenching. These results revealed the contributions of the inadequate precipitation of the strengthening θ′ phase and the increased precipitation of the equilibrium θ phase to the deterioration of the mechanical properties of air-quenched AA2219 DC cast plates. The preexisting GP zones and quenched-in dislocations affected the kinetics of the θ′ phase, whereas the preceding precipitation of the θ′ phase affected the kinetics of the θ phase by controlling its precipitation mechanism.

  19. Investigation of Asphaltene Precipitation at Elevated Temperature

    DEFF Research Database (Denmark)

    Andersen, Simon Ivar; Lindeloff, Niels; Stenby, Erling Halfdan

    1998-01-01

    In order to obtain quantitative data on the asphaltene precipitation induced by the addition of n-alkane (heptane) at temperatures above the normal boiling point of the precipitant, a high temperature/high pressure filtration apparatus has been constructed. Oil and alkane are mixed...

  20. Measurement of precipitation using lysimeters

    Science.gov (United States)

    Fank, Johann; Klammler, Gernot

    2013-04-01

    Austria's alpine foothill aquifers contain important drinking water resources, but are also used intensively for agricultural production. These groundwater bodies are generally recharged by infiltrating precipitation. A sustainable water resources management of these aquifers requires quantifying real evapotranspiration (ET), groundwater recharge (GR), precipitation (P) and soil water storage change (ΔS). While GR and ΔS can be directly measured by weighable lysimeters and P by separate precipitation gauges, ET is determined by solving the climatic water balance ET = P GR ± ΔS. According to WMO (2008) measurement of rainfall is strongly influenced by precipitation gauge errors. Most significant errors result from wind loss, wetting loss, evaporation loss, and due to in- and out-splashing of water. Measuring errors can be reduced by a larger area of the measuring gaugés surface and positioning the collecting vessel at ground level. Modern weighable lysimeters commonly have a surface of 1 m², are integrated into their typical surroundings of vegetation cover (to avoid oasis effects) and allow scaling the mass change of monolithic soil columns in high measuring accuracy (0.01 mm water equivalent) and high temporal resolution. Thus, also precipitation can be quantified by measuring the positive mass changes of the lysimeter. According to Meissner et al. (2007) also dew, fog and rime can be determined by means of highly precise weighable lysimeters. Furthermore, measuring precipitation using lysimeters avoid common measuring errors (WMO 2008) at point scale. Though, this method implicates external effects (background noise, influence of vegetation and wind) which affect the mass time series. While the background noise of the weighing is rather well known and can be filtered out of the mass time series, the influence of wind, which blows through the vegetation and affects measured lysimeter mass, cannot be corrected easily since there is no clear relation between

  1. Evaluation of ERA-Interim precipitation data in complex terrain

    Science.gov (United States)

    Gao, Lu; Bernhardt, Matthias; Schulz, Karsten

    2013-04-01

    Precipitation controls a large variety of environmental processes, which is an essential input parameter for land surface models e.g. in hydrology, ecology and climatology. However, rain gauge networks provides the necessary information, are commonly sparse in complex terrains, especially in high mountainous regions. Reanalysis products (e.g. ERA-40 and NCEP-NCAR) as surrogate data are increasing applied in the past years. Although they are improving forward, previous studies showed that these products should be objectively evaluated due to their various uncertainties. In this study, we evaluated the precipitation data from ERA-Interim, which is a latest reanalysis product developed by ECMWF. ERA-Interim daily total precipitation are compared with high resolution gridded observation dataset (E-OBS) at 0.25°×0.25° grids for the period 1979-2010 over central Alps (45.5-48°N, 6.25-11.5°E). Wet or dry day is defined using different threshold values (0.5mm, 1mm, 5mm, 10mm and 20mm). The correspondence ratio (CR) is applied for frequency comparison, which is the ratio of days when precipitation occurs in both ERA-Interim and E-OBS dataset. The result shows that ERA-Interim captures precipitation occurrence very well with a range of CR from 0.80 to 0.97 for 0.5mm to 20mm thresholds. However, the bias of intensity increases with rising thresholds. Mean absolute error (MAE) varies between 4.5 mm day-1 and 9.5 mm day-1 in wet days for whole area. In term of mean annual cycle, ERA-Interim almost has the same standard deviation of the interannual variability of daily precipitation with E-OBS, 1.0 mm day-1. Significant wet biases happened in ERA-Interim throughout warm season (May to August) and dry biases in cold season (November to February). The spatial distribution of mean annual daily precipitation shows that ERA-Interim significant underestimates precipitation intensity in high mountains and northern flank of Alpine chain from November to March while pronounced

  2. High Resolution, High-Speed Photography, an Increasingly Prominent Diagnostic in Ballistic Research Experiments

    International Nuclear Information System (INIS)

    Shaw, L.; Muelder, S.

    1999-01-01

    High resolution, high-speed photography is becoming a prominent diagnostic in ballistic experimentation. The development of high speed cameras utilizing electro-optics and the use of lasers for illumination now provide the capability to routinely obtain high quality photographic records of ballistic style experiments. The purpose of this presentation is to review in a visual manner the progress of this technology and how it has impacted ballistic experimentation. Within the framework of development at LLNL, we look at the recent history of large format high-speed photography, and present a number of photographic records that represent the state of the art at the time they were made. These records are primarily from experiments involving shaped charges. We also present some examples of current photographic technology, developed within the ballistic community, that has application to hydro diagnostic experimentation at large. This paper is designed primarily as an oral-visual presentation. This written portion is to provide general background, a few examples, and a bibliography

  3. Effects of turbulence on warm clouds and precipitation with various aerosol concentrations

    Science.gov (United States)

    Lee, Hyunho; Baik, Jong-Jin; Han, Ji-Young

    2015-02-01

    This study investigates the effects of turbulence-induced collision enhancement (TICE) on warm clouds and precipitation by changing the cloud condensation nuclei (CCN) number concentration using a two-dimensional dynamic model with bin microphysics. TICE is determined according to the Taylor microscale Reynolds number and the turbulent dissipation rate. The thermodynamic sounding used in this study is characterized by a warm and humid atmosphere with a capping inversion layer, which is suitable for simulating warm clouds. For all CCN concentrations, TICE slightly reduces the liquid water path during the early stage of cloud development and accelerates the onset of surface precipitation. However, changes in the rainwater path and in the amount of surface precipitation that are caused by TICE depend on the CCN concentrations. For high CCN concentrations, the mean cloud drop number concentration (CDNC) decreases and the mean effective radius increases due to TICE. These changes cause an increase in the amount of surface precipitation. However, for low CCN concentrations, changes in the mean CDNC and in the mean effective radius induced by TICE are small and the amount of surface precipitation decreases slightly due to TICE. A decrease in condensation due to the accelerated coalescence between droplets explains the surface precipitation decrease. In addition, an increase in the CCN concentration can lead to an increase in the amount of surface precipitation, and the relationship between the CCN concentration and the amount of surface precipitation is affected by TICE. It is shown that these results depend on the atmospheric relative humidity.

  4. Increasing influence of air temperature on upper Colorado River streamflow

    Science.gov (United States)

    Woodhouse, Connie A.; Pederson, Gregory T.; Morino, Kiyomi; McAfee, Stephanie A.; McCabe, Gregory J.

    2016-01-01

    This empirical study examines the influence of precipitation, temperature, and antecedent soil moisture on upper Colorado River basin (UCRB) water year streamflow over the past century. While cool season precipitation explains most of the variability in annual flows, temperature appears to be highly influential under certain conditions, with the role of antecedent fall soil moisture less clear. In both wet and dry years, when flow is substantially different than expected given precipitation, these factors can modulate the dominant precipitation influence on streamflow. Different combinations of temperature, precipitation, and soil moisture can result in flow deficits of similar magnitude, but recent droughts have been amplified by warmer temperatures that exacerbate the effects of relatively modest precipitation deficits. Since 1988, a marked increase in the frequency of warm years with lower flows than expected, given precipitation, suggests continued warming temperatures will be an increasingly important influence in reducing future UCRB water supplies.

  5. Climate-change driven increase in high intensity rainfall events: Analysis of development in the last decades and towards an extrapolation of future progression

    Science.gov (United States)

    Müller, Eva; Pfister, Angela; Gerd, Büger; Maik, Heistermann; Bronstert, Axel

    2015-04-01

    Hydrological extreme events can be triggered by rainfall on different spatiotemporal scales: river floods are typically caused by event durations of between hours and days, while urban flash floods as well as soil erosion or contaminant transport rather result from storms events of very short duration (minutes). Still, the analysis of climate change impacts on rainfall-induced extreme events is usually carried out using daily precipitation data at best. Trend analyses of extreme rainfall at sub-daily or even sub-hourly time scales are rare. In this contribution two lines of research are combined: first, we analyse sub-hourly rainfall data for several decades in three European regions.Second, we investigate the scaling behaviour of heavy short-term precipitation with temperature, i.e. the dependence of high intensity rainfall on the atmospheric temperature at that particular time and location. The trend analysis of high-resolution rainfall data shows for the first time that the frequency of short and intensive storm events in the temperate lowland regions in Germany has increased by up to 0.5 events per year over the last decades. I.e. this trend suggests that the occurrence of these types of storms have multiplied over only a few decades. Parallel to the changes in the rainfall regime, increases in the annual and seasonal average temperature and changes in the occurrence of circulation patterns responsible for the generation of high-intensity storms have been found. The analysis of temporally highly resolved rainfall records from three European regions further indicates that extreme precipitation events are more intense with warmer temperatures during the rainfall event. These observations follow partly the Clausius-Clapeyron relation. Based on this relation one may derive a general rule of maximum rainfall intensity associated to the event temperature, roughly following the Clausius-Clapeyron (CC) relation. This rule might be used for scenarios of future maximum

  6. The nonstationary impact of local temperature changes and ENSO on extreme precipitation at the global scale

    Science.gov (United States)

    Sun, Qiaohong; Miao, Chiyuan; Qiao, Yuanyuan; Duan, Qingyun

    2017-12-01

    The El Niño-Southern Oscillation (ENSO) and local temperature are important drivers of extreme precipitation. Understanding the impact of ENSO and temperature on the risk of extreme precipitation over global land will provide a foundation for risk assessment and climate-adaptive design of infrastructure in a changing climate. In this study, nonstationary generalized extreme value distributions were used to model extreme precipitation over global land for the period 1979-2015, with ENSO indicator and temperature as covariates. Risk factors were estimated to quantify the contrast between the influence of different ENSO phases and temperature. The results show that extreme precipitation is dominated by ENSO over 22% of global land and by temperature over 26% of global land. With a warming climate, the risk of high-intensity daily extreme precipitation increases at high latitudes but decreases in tropical regions. For ENSO, large parts of North America, southern South America, and southeastern and northeastern China are shown to suffer greater risk in El Niño years, with more than double the chance of intense extreme precipitation in El Niño years compared with La Niña years. Moreover, regions with more intense precipitation are more sensitive to ENSO. Global climate models were used to investigate the changing relationship between extreme precipitation and the covariates. The risk of extreme, high-intensity precipitation increases across high latitudes of the Northern Hemisphere but decreases in middle and lower latitudes under a warming climate scenario, and will likely trigger increases in severe flooding and droughts across the globe. However, there is some uncertainties associated with the influence of ENSO on predictions of future extreme precipitation, with the spatial extent and risk varying among the different models.

  7. The effect of precipitation on contaminant dissolution and transport: Analytic solutions

    International Nuclear Information System (INIS)

    Light, W.B.; Chambre, P.L.; Pigford, T.H.; Lee, W.W.L.

    1988-09-01

    We analysed the effect of precipitation on the dissolution and transport rates of a nondecaying contaminant. Precipitation near the waste surface can have a profound effect on dissolution and transport rates. The mass-transfer rate at the waste surface is controlled by the solid-liquid reaction rate to an extent determined by the modified reaction-rate modulus, α. At later times extending to steady state, the mass-transfer rate depends on the location of the precipitation front r/sub p/ and on the solubility ratio C/sub o//C/sub p/. A precipitation front very near the waste surface can change the dissolution mechanism from solubility-diffusion-controlled to chemical-reaction-rate controlled. Precipitation limits the concentration of the contaminant at r > r/sub p/ to C/sub p/, steepening the concentration gradient for dissolution on the waste package side of the front and flattening the gradient for transport in the region outside the front. This increases the rate of contaminant transport from the waste to the front while decreasing the rate of transport away from the front, when compared to the situation without precipitation. The difference in the transport rates at the front is the rate of precipitation. For large changes in solubility, most of the contaminant is immobilized by precipitation, as was observed in a parallel study. The effect of a precipitation front located nearby in surrounding rock is to increase the release rate at the waste surface/rock interface. The increase in release rate at the waste surface is greater the closer the precipitation and the larger the ratio C/sub o//C/sub p/, also observed by others. The release rates of other waste constituents that dissolve congruently with the solubility-controlling matrix can be increased by a local high-solubility region between the waste surface and the precipitation front. 10 refs., 5 figs

  8. Observation of atomic oxygen O(1S) green-line emission in the summer polar upper mesosphere associated with high-energy (≥30 keV) electron precipitation during high-speed solar wind streams

    Science.gov (United States)

    Lee, Young-Sook; Kwak, Young-Sil; Kim, Kyung-Chan; Solheim, Brian; Lee, Regina; Lee, Jaejin

    2017-01-01

    The auroral green-line emission at 557.7 nm wavelength as arising from the atomic oxygen O(1S → 1D) transition typically peaks at an altitude of 100 km specifically in the nightside oval, induced by auroral electrons within an energy range of 100 eV-30 keV. Intense aurora is known as being suppressed by sunlight in summer daytime but usually occurs in low electrical background conductivity. However, in the present study in summer (July) sunlit condition, enhancements of O(1S) emission rates observed by using the Wind Imaging Interferometer/UARS were frequently observed at low altitudes below 90 km, where ice particles are created initially as subvisible and detected as polar mesosphere summer echoes, emerging to be an optical phenomenon of polar mesospheric clouds. The intense O(1S) emission occurring in summer exceeds those occurring in the daytime in other seasons both in occurrence and in intensity, frequently accompanied by occurrences of supersonic neutral velocity (300-1500 m s-1). In the mesosphere, ion motion is controlled by electric field and the momentum is transferred to neutrals. The intense O(1S) emission is well associated with high-energy electron precipitation as observed during an event of high-speed solar wind streams. Meanwhile, since the minimum occurrences of O(1S) emission and supersonic velocity are maintained even in the low precipitation flux, the mechanism responsible is not only related to high-energy electron precipitation but also presumably to the local conditions, including the composition of meteoric-charged ice particles and charge separation expected in extremely low temperatures (<150 K).

  9. Precipitation and Hardening in Magnesium Alloys

    Science.gov (United States)

    Nie, Jian-Feng

    2012-11-01

    Magnesium alloys have received an increasing interest in the past 12 years for potential applications in the automotive, aircraft, aerospace, and electronic industries. Many of these alloys are strong because of solid-state precipitates that are produced by an age-hardening process. Although some strength improvements of existing magnesium alloys have been made and some novel alloys with improved strength have been developed, the strength level that has been achieved so far is still substantially lower than that obtained in counterpart aluminum alloys. Further improvements in the alloy strength require a better understanding of the structure, morphology, orientation of precipitates, effects of precipitate morphology, and orientation on the strengthening and microstructural factors that are important in controlling the nucleation and growth of these precipitates. In this review, precipitation in most precipitation-hardenable magnesium alloys is reviewed, and its relationship with strengthening is examined. It is demonstrated that the precipitation phenomena in these alloys, especially in the very early stage of the precipitation process, are still far from being well understood, and many fundamental issues remain unsolved even after some extensive and concerted efforts made in the past 12 years. The challenges associated with precipitation hardening and age hardening are identified and discussed, and guidelines are outlined for the rational design and development of higher strength, and ultimately ultrahigh strength, magnesium alloys via precipitation hardening.

  10. Long-Term Large-Scale Bias-Adjusted Precipitation Estimates at High Spatial and Temporal Resolution Derived from the National Mosaic and Multi-Sensor QPE (NMQ/Q2) Precipitation Reanalysis over CONUS

    Science.gov (United States)

    Prat, O. P.; Nelson, B. R.; Stevens, S. E.; Seo, D. J.; Kim, B.

    2014-12-01

    The processing of radar-only precipitation via the reanalysis from the National Mosaic and Multi-Sensor Quantitative (NMQ/Q2) based on the WSR-88D Next-generation Radar (Nexrad) network over Continental United States (CONUS) is nearly completed for the period covering from 2000 to 2012. This important milestone constitutes a unique opportunity to study precipitation processes at a 1-km spatial resolution for a 5-min temporal resolution. However, in order to be suitable for hydrological, meteorological and climatological applications, the radar-only product needs to be bias-adjusted and merged with in-situ rain gauge information. Rain gauge networks such as the Hydrometeorological Automated Data System (HADS), the Automated Surface Observing Systems (ASOS), the Climate Reference Network (CRN), and the Global Historical Climatology Network - Daily (GHCN-D) are used to adjust for those biases and to merge with the radar only product to provide a multi-sensor estimate. The challenges related to incorporating non-homogeneous networks over a vast area and for a long-term record are enormous. Among the challenges we are facing are the difficulties incorporating differing resolution and quality surface measurements to adjust gridded estimates of precipitation. Another challenge is the type of adjustment technique. After assessing the bias and applying reduction or elimination techniques, we are investigating the kriging method and its variants such as simple kriging (SK), ordinary kriging (OK), and conditional bias-penalized Kriging (CBPK) among others. In addition we hope to generate estimates of uncertainty for the gridded estimate. In this work the methodology is presented as well as a comparison between the radar-only product and the final multi-sensor QPE product. The comparison is performed at various time scales from the sub-hourly, to annual. In addition, comparisons over the same period with a suite of lower resolution QPEs derived from ground based radar

  11. Silver precipitation from electrolytic effluents

    International Nuclear Information System (INIS)

    Rivera, I.; Patino, F.; Cruells, M.; Roca, A.; Vinals, J.

    2004-01-01

    The recovery of silver contained in electrolytic effluents is attractive due to its high economic value. These effluents are considered toxic wastes and it is not possible to dump them directly without any detoxification process. One of the most important way for silver recovery is the precipitation with sodium ditionite, sodium borohidride or hydrazine monohidrate. In this work, the most significant aspects related to the use of these reagents is presented. Results of silver precipitation with sodium ditionite from effluents containing thiosulfate without previous elimination of other species are also presented. silver concentration in the final effluents w <1 ppm. (Author) 15 refs

  12. Effects of welding and post-weld heat treatments on nanoscale precipitation and mechanical properties of an ultra-high strength steel hardened by NiAl and Cu nanoparticles

    International Nuclear Information System (INIS)

    Jiao, Z.B.; Luan, J.H.; Guo, W.; Poplawsky, J.D.; Liu, C.T.

    2016-01-01

    The effects of welding and post-weld heat treatment (PWHT) on nanoscale co-precipitation, grain structure, and mechanical properties of an ultra-high strength steel were studied through a combination of atom probe tomography (APT) and mechanical tests. Our results indicate that the welding process dissolves all pre-existing nanoparticles and causes grain coarsening in the fusion zone, resulting in a soft and ductile weld without any cracks in the as-welded condition. A 550 °C PWHT induces fine-scale re-precipitation of NiAl and Cu co-precipitates with high number densities and ultra-fine sizes, leading to a large recovery of strength but a loss of ductility with intergranular failure, whereas a 600 °C PWHT gives rise to coarse-scale re-precipitation of nanoparticles together with the formation of a small amount of reverted austenite, resulting in a great recovery in both strength and ductility. Our analysis indicates that the degree of strength recovery is dependent mainly upon the re-precipitation microstructure of nanoparticles, together with grain size and reversion of austenite, while the ductility recovery is sensitive to the grain-boundary structure. APT reveals that the grain-boundary segregation of Mn and P may be the main reason for the 550 °C embrittlement, and the enhanced ductility at 600 °C is ascribed to a possible reduction of the segregation and reversion of austenite.

  13. Uranium precipitation with hydrogen peroxide

    International Nuclear Information System (INIS)

    Brown, R.A.

    1980-01-01

    Although hydrogen peroxide precipitation of uranium continues to be used primarily as means of producing a high purity yellowcake, it has also become an important process due to its superior physical properties. Processing costs such as filtering, drying and/or calcining and drumming, can be reduced. 5 refs

  14. Metabolic fingerprinting of high-fat plasma samples processed by centrifugation- and filtration-based protein precipitation delineates significant differences in metabolite information coverage.

    Science.gov (United States)

    Barri, Thaer; Holmer-Jensen, Jens; Hermansen, Kjeld; Dragsted, Lars O

    2012-03-09

    Metabolomics and metabolic fingerprinting are being extensively employed for improved understanding of biological changes induced by endogenous or exogenous factors. Blood serum or plasma samples are often employed for metabolomics studies. Plasma protein precipitation (PPP) is currently performed in most laboratories before LC-MS analysis. However, the impact of fat content in plasma samples on metabolite coverage has not previously been investigated. Here, we have studied whether PPP procedures influence coverage of plasma metabolites from high-fat plasma samples. An optimized UPLC-QTOF/MS metabolic fingerprinting approach and multivariate modeling (PCA and OPLS-DA) were utilized for finding characteristic metabolite changes induced by two PPP procedures; centrifugation and filtration. We used 12-h fasting samples and postprandial samples collected at 2h after a standardized high-fat protein-rich meal in obese non-diabetic subjects recruited in a dietary intervention. The two PPP procedures as well as external and internal standards (ISs) were used to track errors in response normalization and quantification. Remarkably and sometimes uniquely, the fPPP, but not the cPPP approach, recovered not only high molecular weight (HMW) lipophilic metabolites, but also small molecular weight (SMW) relatively polar metabolites. Characteristic SMW markers of postprandial samples were aromatic and branched-chain amino acids that were elevated (p<0.001) as a consequence of the protein challenge. In contrast, some HMW lipophilic species, e.g. acylcarnitines, were moderately lower (p<0.001) in postprandial samples. LysoPCs were largely unaffected. In conclusion, the fPPP procedure is recommended for processing high-fat plasma samples in metabolomics studies. While method improvements presented here were clear, use of several ISs revealed substantial challenges to untargeted metabolomics due to large and variable matrix effects. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Homogeneous Precipitation Synthesis and Magnetic Properties of Cobalt Ferrite Nanoparticles

    Directory of Open Access Journals (Sweden)

    Zhigang Liu

    2008-01-01

    Full Text Available Magnetic nanoparticles (NPs of cobalt ferrite have been synthesized via a homogeneous precipitation route using hexamethylenetetramine (HMT as the precipitant. The particle size, crystal structure, and magnetic properties of the synthesized particles were investigated by X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer. The NPs are of cubic inverse spinel structure and nearly spherical shape. With the increase of oxidation time from 30 to 180 minutes in the reaction solution at 90∘C, the average particle size increases from ~30 nm to ~45 nm. The as-synthesized NPs ~30 nm in size show higher Ms (61.5 emu/g and moderate Hc (945 Oe and Mr/Ms (0.45 value compared with the materials synthesized by coprecipitation method using NaOH as precipitate at high pH value.

  16. Precipitation process for supernate decontamination

    International Nuclear Information System (INIS)

    Lee, L.M.; Kilpatrick, L.L.

    1982-11-01

    A precipitation and adsorption process has been developed to remove cesium, strontium, and plutonium from water-soluble, high-level radioactive waste. An existing waste tank serves as the reaction vessel and the process begins with the addition of a solution of sodium tetraphenylborate and a slurry of sodium titanate to the contained waste salt solution. Sodium tetraphenylborate precipitates the cesium and sodium titanate adsorbs the strontium and plutonium. The precipitate/adsorbate is then separated from the decontaminated salt solution by crossflow filtration. This new process offers significant capital savings over an earlier ion exchange process for salt decontamination. Chemical and small-scale engineering studies with actual waste are reported. The effect of many variables on the decontamination factors and filter performance are defined

  17. Trends in total and daily precipitation indices in japan from 1901 to 2000

    OpenAIRE

    Nagata, Rena; Zaiki, Masumi

    2008-01-01

    Long-term trends in seasonal precipitation amount and daily precipitation indices were investigated for spring, summer, autumn, and winter with a daily precipitation dataset for Japan from 1901 to 2000. Heavy precipitation in spring and summer has significantly increased along the west coast of Japan. Such changes in precipitation have resulted in the increased heavy precipitation intensity. For autumn and winter, total precipitation significantly decreased in the Kanto district and central J...

  18. CMORPH 8 Km: A Method that Produces Global Precipitation Estimates from Passive Microwave and Infrared Data at High Spatial and Temporal Resolution

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A new technique is presented in which half-hourly global precipitation estimates derived from passive microwave satellite scans are propagated by motion vectors...

  19. Cerium oxalate precipitation

    International Nuclear Information System (INIS)

    Chang, T.P.

    1987-02-01

    Cerium, a nonradioactive, common stand-in for plutonium in development work, has been used to simulate several plutonium precipitation processes at the Savannah River Laboratory. There are similarities between the plutonium trifluoride and the cerium oxalate precipitations in particle size and extent of plating, but not particle morphology. The equilibrium solubility, precipitation kinetics, particle size, extent of plating, and dissolution characteristics of cerium oxalate have been investigated. Interpretations of particle size and plating based on precipitation kinetics (i.e., nucleation and crystal growth) are presented. 16 refs., 7 figs., 6 tabs

  20. Modeling the effects of ion dose and crystallographic symmetry on the morphological evolution of embedded precipitates under thermal annealing

    International Nuclear Information System (INIS)

    Li, Kun-Dar

    2014-01-01

    Highlights: •We model the faceted precipitates formation by post-implantation annealing. •The anisotropic interfacial energy and diffusion kinetics play crucial roles. •The evolutions of faceted precipitates, including Ostwald ripening, are revealed. •The mechanism of the nucleation and growth is based on the atomic diffusion. •The effects of ion dose and crystallographic symmetry are also investigated. -- Abstract: Thermal annealing is one of the most common techniques to synthesize embedded precipitates by ion implantation process. In this study, an anisotropic phase field model is presented to investigate the effects of ion dose and crystallographic symmetry on the morphological formation and evolution of embedded precipitates during post-implantation thermal annealing process. This theoretical model provides an efficient numerical approach to understand the phenomenon of faceted precipitates formation by ion implantation. As a theoretical analysis, the interfacial energy and diffusion kinetics play prominent roles in the mechanism of atomic diffusion for the precipitates formation. With a low ion dose, faceted precipitates are developed by virtue of the anisotropic interfacial energy. As an increase of ion dose, connected precipitates with crystallographic characters on the edge are appeared. For a high ion dose, labyrinth-like nanostructures of precipitates are produced and the characteristic morphology of crystallographic symmetry becomes faint. These simulation results for the morphological evolutions of embedded precipitates by ion implantation are corresponded with many experimental observations in the literatures. The quantitative analyses of the simulations are also well described the consequence of precipitates formation under different conditions

  1. High Relative Abundance of Biofuel Sourced Ethanol in Precipitation in the US and Brazil Determined Using Compound Specific Stable Carbon Isotopes

    Science.gov (United States)

    Shimizu, M. S.; Felix, J. D. D.; Casas, M.; Avery, G. B., Jr.; Kieber, R. J.; Mead, R. N.; Willey, J. D.; Lane, C.

    2017-12-01

    Ethanol biofuel production and consumption have increased exponentially over the last two decades to help reduce greenhouse gas emissions. Currently, 85% of global ethanol production and consumption occurs in the US and Brazil. Increasing biofuel ethanol usage in these two countries enhances emissions of uncombusted ethanol to the atmosphere contributing to poor air quality. Although measurements of ethanol in the air and the precipitation reveal elevated ethanol concentrations in densely populated cities, other sources such as natural vegetation can contribute to emission to the atmosphere. Previous modeling studies indicated up to 12% of atmospheric ethanol is from anthropogenic emissions. Only one gas phase study in southern Florida attempted to constrain the two sources through direct isotopic measurements. The current study used a stable carbon isotope method to constrain sources of ethanol in rainwater from the US and Brazil. A method was developed using solid phase microextraction (SPME) with subsequent analysis by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). Stable carbon isotope signatures (δ13C) of vehicle ethanol emission sources for both the US (-9.8‰) and Brazil (-12.7‰) represented C4 plants as feedstock (corn and sugarcane) for biofuel production. An isotope mixing model using biofuel from vehicles (C4 plants) and biogenic (C3 plants) end-members was implemented to estimate ethanol source apportionment in the rain. We found that stable carbon isotope ratio of ethanol in the rain ranged between -22.6‰ and -12.7‰. Our results suggest that the contribution of biofuel to atmospheric ethanol can be higher than previously estimated. As biofuel usage increasing globally, it is essential to determine the relative abundance of anthropogenic ethanol in other areas of the world.

  2. Experimental study of diffuse auroral precipitations

    International Nuclear Information System (INIS)

    Mouaia, K.

    1983-01-01

    First chapter is devoted to low energy electron precipitation in the evening sector of the auroral magnetosphere, during quiet and disturbed magnetic periods. Four subjects are studied in detail: the latitude distribution of the varied auroral forms and their relations to external magnetosphere; the time coefficients related to precipitations, the form and the dynamic of the diffuse precipitation equatorial frontier; the precipitation effect on the ionosphere concentration. The last part of the chapter shows that the plasma convection in the magnetosphere, associated to wave-particle interactions near the equatorial accounts for the principal characteristics of the evening sector diffuse electronic precipitations. The second chapter deals with subauroral precipitations of low energy ions, after the magnetospheric substorms, in the high latitude regions of the morning sector [fr

  3. Influence of chemical composition of precipitation on migration of radioactive caesium in natural soils

    International Nuclear Information System (INIS)

    Thørring, H.; Skuterud, L.; Steinnes, E.

    2014-01-01

    The aim of the present work was to study the impact of the chemical composition of precipitation on radiocaesium mobility in natural soil. This was done through column studies. Three types of precipitation regimes were studied, representing a natural range found in Norway: Acidic precipitation (southernmost part of the country); precipitation rich in marine cations (highly oceanic coastal areas); and low concentrations of sea salts (slightly continental inland areas). After 50 weeks and a total precipitation supply of ∼10 000 L m −2 per column, results indicate that acidic precipitation increased the mobility of 134 Cs added during the experiment. However, depth distribution of already present Chernobyl fallout 137 Cs was not significantly affected by the chemical composition of precipitation. - Highlights: • Mobility of freshly added Cs-134 was higher in soil receiving acidic precipitation. • Depth penetration of Cs-134 was higher in soil profiles with a thicker humus layer. • Depth distribution of Chernobyl Cs-137 was not affected by precipitation type

  4. Highly transparent Tb3Al5O12 magneto-optical ceramics sintered from co-precipitated powders with sintering aids

    Science.gov (United States)

    Dai, Jiawei; Pan, Yubai; Xie, Tengfei; Kou, Huamin; Li, Jiang

    2018-04-01

    Highly transparent terbium aluminum garnet (Tb3Al5O12, TAG) magneto-optical ceramics were fabricated from co-precipitated nanopowders with tetraethoxysilane (TEOS) as sintering aid by vacuum sintering combined with hot isostatic pressing (HIP) post-treatment. The ball milled TAG powder shows better dispersity than the as-synthesized powder, and its average particle size is about 80 nm. For the ceramic sample pre-sintered at 1720 °C for 20 h with HIP post-treated at 1700 °C for 3 h, the in-line transmittance exceeds 76% in the region of 400-1580nm (except the absorption band), reaching a maximum value of 81.8% at the wavelength of 1390 nm. The microstructure of the TAG ceramic is homogeneous and its average grain size is approximately 19.7 μm. The Verdet constant of the sample is calculated to be -182.7 rad·T-1·m-1 at room temperature.

  5. Development of a confirmatory method for detecting recombinant bovine somatotropin in plasma by immunomagnetic precipitation followed by ultra-high performance liquid chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Robert, Christelle; Huet, Anne-Catherine; Suárez-Pantaleón, Célia; Brasseur, Amaury; Delahaut, Philippe; Gillard, Nathalie

    2017-11-01

    Recombinant bovine somatotropin (rbST), a synthetic growth hormone, is used to stimulate growth and enhance milk production in dairy cows. Both its use and the sale of dairy products from treated animals are prohibited in the European Union, as well as in Australia, Canada, Japan, and New Zealand, but authorised in several countries (e.g. Brazil, USA). Screening methods involve detecting anti-rbST antibodies (biomarkers) in treated cows. Confirmatory methods are required to prove rbST abuse. The major challenges in determining rbST are its potentially low levels, its high similarity to native bST, and matrix interferences. To overcome these obstacles, we have developed a method involving immunomagnetic precipitation followed by UHPLC-MS/MS for rbST detection. Briefly, protein G magnetic beads pre-coated with an in-house produced monoclonal antibody were added to plasma. Incubation at room temperature allowed rbST present in the sample to bind to the magnetic beads. After that, magnetic beads were isolated by centrifugation and thoroughly washed (PBS, PBS + 0.2% Tween 20). Finally, rbST was released by alkalinisation and the samples were trypsin digested prior to UHPLC-MS/MS analysis in the MRM mode. Validation was done in accordance with European Commission Decision 2002/657/CE. Matrix-matched calibration with internal standards was used. The decision limit (CCα) reached with this approach was 0.11 µg l -1 .

  6. Preparation of Vitexin Nanoparticles by Combining the Antisolvent Precipitation and High Pressure Homogenization Approaches Followed by Lyophilization for Dissolution Rate Enhancement.

    Science.gov (United States)

    Gu, Chengbo; Liu, Ziwei; Yuan, Xiaohan; Li, Wang; Zu, Yuangang; Fu, Yujie

    2017-11-22

    Vitexin, a natural flavonoid found in many medicinal plants, is well known for its rich pharmacological activities. However, the poor water solubility of vitexin has limited its therapeutic application. The aim of this study was to prepare the nanoparticles of vitexin by combining the antisolvent precipitation (ASP) and high pressure homogenization (HPH) approaches followed by lyophilization for improving the dissolution rate of this poorly water-soluble drug. The effects of main factors influencing the mean particle size (MPS) of vitexin were investigated and optimized. Under optimum conditions, vitexin nanosuspensions with an MPS of 80.5 nm were obtained and then lyophilized to form nanoparticles. The obtained vitexin nanoparticles were further characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), mass spectrometry (MS), X-ray powder diffraction (XRPD), gas chromatography (GC) and dissolution testing. The results showed that the nanoparticles of vitexin were converted into an amorphous form, with its chemical structure unchanged. Additionally, the residual dimethyl sulfoxide (DMSO) is lower than the International Conference on Harmonization (ICH) limit for class 3 solvents. The dissolution rate of processed vitexin was significantly higher (5.58-fold) than that of raw drug. Overall, the combinative process we developed is an effective way to produce vitexin nanoparticles with markedly enhanced dissolution rate.

  7. Three-Dimensional Storm Structure and Low-Level Boundaries at Different Stages of Cyclic Mesocyclone Evolution in a High-Precipitation Tornadic Supercell

    Directory of Open Access Journals (Sweden)

    Daniel P. Betten

    2018-01-01

    Full Text Available Nearly continuous wind retrievals every three minutes for an unprecedented 90-minute period were constructed during multiple mesocyclone cycles in a tornadic high-precipitation supercell. Asymptotic contraction rate analysis revealed the relationship between the primary and secondary rear-flank gust fronts (RFGF and SRFGFs and the rear-flank downdraft (RFD and occlusion downdrafts. This is thought to be the first radar-based analysis where the relationship between the near-surface gust fronts and their parent downdrafts has been explored for sequential mesocyclones. Changes in the SRFGFs were associated with surges in the RFD. During part of the mesocyclone lifecycle, the SRFGF produced a band of low-level convergence and associated deep updraft along the southwestern side of the hook echo region that ingested the RFD outflow and limited both entrainment into the RFD and reinforcement of low-level convergence along the leading edge of the primary RFGF. The second mesocyclone intensified from stretching in an occlusion updraft rather than in the primary updraft. This low-level mesocyclone remained well separated from the updraft shear region vorticity that was associated with a more traditional midlevel mesocyclone. However, the third mesocyclone initiated in the vorticity-rich region of the primary updraft zone and was amplified by stretching in the primary updraft.

  8. Investigating precipitation changes of anthropic origin: data and methodological issues

    Science.gov (United States)

    de Lima, Isabel; Lovejoy, Shaun

    2017-04-01

    There is much concern about the social, environmental and economic impacts of climate change that could result directly from changes in temperature and precipitation. For temperature, the situation is better understood; but despite the many studies that have been already dedicated to precipitation, change in this process - that could be associated to the transition to the Anthropocene - has not yet been convincingly proven. A large fraction of those studies have been exploring temporal (linear) trends in local precipitation, sometimes using records over only a few decades; other fewer studies have been dedicated to investigating global precipitation change. Overall, precipitation change of anthropic origin has showed to be difficult to establish with high statistical significance and, moreover, different data and products have displayed important discrepancies; this is valid even for global precipitation. We argue that the inadequate resolution and length of the data commonly used, as well as methodological issues, are among the main factors limiting the ability to identify the signature of change in precipitation. We propose several ways in which one can hope to improve the situation - or at least - clarify the difficulties. From the point of view of statistical analysis, the problem is one of detecting a low frequency anthropogenic signal in the presence of "noise" - the natural variability (the latter includes both internal dynamics and responses to volcanic, solar or other natural forcings). A consequence is that as one moves to longer and longer time scales, fluctuations are increasingly averaged and at some point, the anthropogenic signal will stand out above the natural variability noise. This approach can be systematized using scaling fluctuation analysis to characterizing different precipitation scaling regimes: weather, macroweather, climate - from higher to lower frequencies; in the anthropocene, the macroweather regime covers the range of time scales

  9. Increased physical activity ameliorates high fat diet-induced bone resorption in mice

    Science.gov (United States)

    It has been recognized that mechanical stresses associated with physical activity (PA) have beneficial effects on increasing bone mineral density (BMD) and improving bone quality. On the other hand, high fat diet (HFD) and obesity increase bone marrow adiposity leading to increased excretion of pro-...

  10. Moderate High Fat Diet Increases Sucrose Self-Administration In Young Rats

    OpenAIRE

    Figlewicz, Dianne P.; Jay, Jennifer L.; Acheson, Molly A.; Magrisso, Irwin J.; West, Constance H.; Zavosh, Aryana; Benoit, Stephen C.; Davis, Jon F.

    2012-01-01

    We have previously reported that a moderately high fat diet increases motivation for sucrose in adult rats. In this study, we tested the motivational, neurochemical, and metabolic effects of the high fat diet in male rats transitioning through puberty, during 5-8 weeks of age. We observed that the high fat diet increased motivated responding for sucrose, which was independent of either metabolic changes or changes in catecholamine neurotransmitter metabolites in the nucleus accumbens. However...

  11. Landscape runoff, precipitation variation and reservoir limnology

    OpenAIRE

    Geraldes, Ana Maria

    2010-01-01

    Landscape runoff potential impact on reservoir limnology was indirectly evaluated by assessing the effect of precipitation variation on several water quality parameters, on Anabaena (Cyanophyta) and crustacean zooplankton abundances. The obtained results showed that total phosphorus increased with strong precipitation events whereas water transparency presented an opposite trend. Wet periods followed by long dry periods favored Anabaena dominance, which induced a...

  12. Application of probabilistic precipitation forecasts from a ...

    African Journals Online (AJOL)

    2014-02-14

    Feb 14, 2014 ... Application of probabilistic precipitation forecasts from a deterministic model ... aim of this paper is to investigate the increase in the lead-time of flash flood warnings of the SAFFG using probabilistic precipitation forecasts ... The procedure is applied to a real flash flood event and the ensemble-based.

  13. CMIP5 model simulations of Ethiopian Kiremt-season precipitation: current climate and future changes

    Science.gov (United States)

    Li, Laifang; Li, Wenhong; Ballard, Tristan; Sun, Ge; Jeuland, Marc

    2016-05-01

    Kiremt-season (June-September) precipitation provides a significant water supply for Ethiopia, particularly in the central and northern regions. The response of Kiremt-season precipitation to climate change is thus of great concern to water resource managers. However, the complex processes that control Kiremt-season precipitation challenge the capability of general circulation models (GCMs) to accurately simulate precipitation amount and variability. This in turn raises questions about their utility for predicting future changes. This study assesses the impact of climate change on Kiremt-season precipitation using state-of-the-art GCMs participating in the Coupled Model Intercomparison Project Phase 5. Compared to models with a coarse resolution, high-resolution models (horizontal resolution <2°) can more accurately simulate precipitation, most likely due to their ability to capture precipitation induced by topography. Under the Representative Concentration Pathway (RCP) 4.5 scenario, these high-resolution models project an increase in precipitation over central Highlands and northern Great Rift Valley in Ethiopia, but a decrease in precipitation over the southern part of the country. Such a dipole pattern is attributable to the intensification of the North Atlantic subtropical high (NASH) in a warmer climate, which influences Ethiopian Kiremt-season precipitation mainly by modulating atmospheric vertical motion. Diagnosis of the omega equation demonstrates that an intensified NASH increases (decreases) the advection of warm air and positive vorticity into the central Highlands and northern Great Rift Valley (southern part of the country), enhancing upward motion over the northern Rift Valley but decreasing elsewhere. Under the RCP 4.5 scenario, the high-resolution models project an intensification of the NASH by 15 (3 × 105 m2 s-2) geopotential meters (stream function) at the 850-hPa level, contributing to the projected precipitation change over Ethiopia. The

  14. Highly loaded behavior of kinesins increases the robustness of transport under high resisting loads.

    Directory of Open Access Journals (Sweden)

    Woochul Nam

    2015-03-01

    Full Text Available Kinesins are nano-sized biological motors which walk by repeating a mechanochemical cycle. A single kinesin molecule is able to transport its cargo about 1 μm in the absence of external loads. However, kinesins perform much longer range transport in cells by working collectively. This long range of transport by a team of kinesins is surprising because the motion of the cargo in cells can be hindered by other particles. To reveal how the kinesins are able to accomplish their tasks of transport in harsh intracellular circumstances, stochastic studies on the kinesin motion are performed by considering the binding and unbinding of kinesins to microtubules and their dependence on the force acting on kinesin molecules. The unbinding probabilities corresponding to each mechanochemical state of kinesin are modeled. The statistical characterization of the instants and locations of binding are captured by computing the probability of unbound kinesin being at given locations. It is predicted that a group of kinesins has a more efficient transport than a single kinesin from the perspective of velocity and run length. Particularly, when large loads are applied, the leading kinesin remains bound to the microtubule for long time which increases the chances of the other kinesins to bind to the microtubule. To predict effects of this behavior of the leading kinesin under large loads on the collective transport, the motion of the cargo is studied when the cargo confronts obstacles. The result suggests that the behavior of kinesins under large loads prevents the early termination of the transport which can be caused by the interference with the static or moving obstacles.

  15. Meteorological features associated with unprecedented precipitation ...

    Indian Academy of Sciences (India)

    Unprecedented precipitation along with heavy falls occurred over many parts of India from 28th February to 2nd March 2015. Many of the stations of northwest and central India received an all time high 24 hr cumulative precipitation of March during this period. Even the national capital, New Delhi, broke all the previous ...

  16. The influence of Cd-dopant on the properties of α-FeOOH and α-Fe2O3 particles precipitated in highly alkaline media

    International Nuclear Information System (INIS)

    Krehula, Stjepko; Music, Svetozar

    2007-01-01

    The effects of Cd-dopant on the phenomenology of the precipitation of α-(Fe, Cd)OOH and α-(Fe, Cd) 2 O 3 particles, the formation of solid solutions, particle size and their geometrical shapes were investigated using Moessbauer and Fourier transform infrared (FT-IR) spectroscopies, field emission scanning electron microscopy (FE SEM) and energy dispersive X-ray analysis (EDS). The formation of merely α-(Fe, Cd)OOH solid solutions was measured up to r = 0.0196, where r = [Cd]/([Cd] + [Fe]). The formation of two types of solid solutions, α-(Fe, Cd)OOH and α-(Fe, Cd) 2 O 3 was found at r between 0.0291 and 0.0698, whereas the formation of an α-(Fe, Cd) 2 O 3 solid solution alone was obtained at r = 0.0909. The incorporation of Cd-substitutions into α-FeOOH and α-Fe 2 O 3 structures decreased the hf > values of the corresponding hyperfine magnetic field. The IR band at 639 cm -1 , recorded for α-FeOOH, was found to be sensitive to Cd-substitutions. With an increased r value a gradual elongation of α-(Fe, Cd)OOH particles along the c-axis was observed, with the maximum elongation (∼600-700 nm) obtained at r = 0.0476. At the same time, particle width (b-axis direction) and thickness (a-axis direction) showed a gradual decrease. With a further increase in the r value the length of α-(Fe, Cd)OOH particles rapidly decreased. α-(Fe, Cd) 2 O 3 particles ∼100-200 nm in size were obtained at r = 0.0909

  17. Precipitation kinetics in warm forming of AW-7020 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, M., E-mail: Manoj.kumar@ait.ac.at [Leichtmetall-Kompetenzzentrum Ranshofen GmbH, Austrian Institute of Technology, Postfach 26, A-5282 Ranshofen (Austria); Institute of Material Science and Technology, TU Vienna (Austria); Poletti, C. [Present address: Institute of Material Science and Welding, TU Graz (Austria); Institute of Material Science and Technology, TU Vienna (Austria); Degischer, H.P. [Institute of Material Science and Technology, TU Vienna (Austria)

    2013-01-20

    The warm formability of the precipitation hardening AW-7020 (AlZn 4.5Mg1) alloy is investigated by testing extruded tubes. The precipitation kinetics of different conditions before and after warm deformation is studied by differential scanning calorimetry and transmission electron microcopy. The precipitation conditions are correlated with the results of hardness tests at room temperature and of tensile tests at temperatures between 200 and 350 Degree-Sign C at different strain rates. The yield strength decreases with increasing test temperature approaching that of samples in the annealed condition, while the strain at fracture increases. The overall influence of the strain rate on ductility is dominated by the corresponding time required for deformation. The formability of the starting condition T1 as well as the corresponding strain hardening exponent is particularly promising for high strain rates at 250 Degree-Sign C, where the metastable precipitates of the T1 condition are dissolved. The short exposure of about 30 s at 250 Degree-Sign C re-establishes the potential for precipitation strengthening by natural ageing after the warm deformation and a following paint baking heat treatment maintains the hardness level.

  18. Removal of salt from rare earth precipitates by vacuum distillation

    International Nuclear Information System (INIS)

    Yang, Hee-Chul; Eun, Hee-Chul; Cho, Yong-Zun; Park, Hwan-Seo; Kim, In-Tae

    2008-01-01

    This study investigated the distillation rates of LiCl-KCl eutectic salt from the rare earth (RE) precipitates originating from the oxygen-sparging RE precipitation process. The first part study investigated distillation rates of eutectic salt under different vacuums at high temperatures by using thermo-gravimetric furnace system. The second part study tested the removal efficiency of eutectic salt from RE precipitates by using the laboratory vacuum distillation furnace system. Investigated variables were the temperature, the degree of vacuum and the time. Salt distillation operation with a moderated distillation rate of 10 -4 - 10 -5 mole sec -1 cm -2 is possible at temperature less than 1300 K and vacuums of 5-50 Torr, by minimizing the potentials of the RE particle entrainment. An increase in the vaporizing surface area is relatively effective for removing the residual salt in pores of bulk of the precipitated RE particles, when compared to that for the vaporizing time. Over 99.9% of the salt removal from the salt-RE precipitate mixture could be achieved by increasing the vaporizing surface area under moderate vacuum conditions of 50 Torr at 1200 K. (author)

  19. PRECIPITATION OF PROTACTINIUM

    Science.gov (United States)

    Moore, R.L.

    1958-07-15

    An lmprovement in the separation of protactinium from aqueous nitric acid solutions is described. 1t covers the use of lead dioxide and tin dioxide as carrier precipitates for the protactinium. In carrying out the process, divalent lead or divalent tin is addcd to the solution and oxidized, causing formation of a carrier precipitate of lead dioxide or stannic oxide, respectively.

  20. Global Precipitation Measurement Poster

    Science.gov (United States)

    Azarbarzin, Art

    2010-01-01

    This poster presents an overview of the Global Precipitation Measurement (GPM) constellation of satellites which are designed to measure the Earth's precipitation. It includes the schedule of launches for the various satellites in the constellation, and the coverage of the constellation, It also reviews the mission capabilities, and the mission science objectives.

  1. H-Phase Precipitation and Martensitic Transformation in Ni-rich Ni-Ti-Hf and Ni-Ti-Zr High-Temperature Shape Memory Alloys

    Science.gov (United States)

    Evirgen, A.; Pons, J.; Karaman, I.; Santamarta, R.; Noebe, R. D.

    2018-03-01

    The distributions of H-phase precipitates in Ni50.3Ti29.7Hf20 and Ni50.3Ti29.7Zr20 alloys formed by aging treatments at 500 and 550 °C or slow furnace cooling and their effects on the thermal martensitic transformation have been investigated by TEM and calorimetry. The comparative study clearly reveals faster precipitate-coarsening kinetics in the NiTiZr alloy than in NiTiHf. For precipitates of a similar size of 10-20 nm in both alloys, the martensite plates in Ni50.3Ti29.7Zr20 have larger widths and span a higher number of precipitates compared with the Ni50.3Ti29.7Hf20 alloy. However, for large H-phase particles with hundreds of nm in length, no significant differences in the martensitic microstructures of both alloy systems have been observed. The martensitic transformation temperatures of Ni50.3Ti29.7Hf20 are 80-90 °C higher than those of Ni50.3Ti29.7Zr20 in the precipitate-free state and in the presence of large particles of hundreds on nm in length, but this difference is reduced to only 10-20 °C in samples with small H-phase precipitates. The changes in the transformation temperatures are consistent with the differences in the precipitate distributions between the two alloy systems observed by TEM.

  2. Rapid precipitation of silica (opal-A) disguises evidence of biogenicity in high-temperature geothermal deposits: Case study from Dagunguo hot spring, China

    Science.gov (United States)

    Peng, Xiaotong; Jones, Brian

    2012-06-01

    Dagunguo Spring, located in the Tengchong geothermal area in the western part of Yunnan Province, China, is a very active spring with water temperatures of 78 to 97 °C and pH of 7.7 to 8.8. The vent pool, 5.6 m in diameter and up to 1.5 m deep, is lined with opal-A that was precipitated from the near-boiling spring waters. A glass suspended in the pool was coated with opal-A in two months and two PVC pipes that drained water from the pool in late 2010 became lined with opal-A precipitates in less than three months. The opal-A accumulated at rates of 0.5 to 0.75 mm/month in the spring pool and 2.5 to 3.5 mm/month in the PVC pipes. The opal-A precipitates, irrespective of where they developed, are formed primarily of silicified microbes and opal-A spheres along with minor amounts of native sulfur, detrital quartz, and clay (mainly kaolinite). The fabrics in these opal-A deposits were dictated largely by the growth patterns of the filamentous and rod-shaped microbes that dominate this low-diversity biota and the amount of opal-A that was precipitated around them. Many of the microbes were preserved as rapid opal-A was precipitated on and around them before the cells decayed. With continued precipitation, however, the microbes became quickly engulfed in the opal-A precipitates and morphological evidence of their presence was lost. In essence, the process that controls their preservation ultimately disguised them to the point where cannot be seen. Critically, this loss of morphological identity takes places even before opal-A starts its diagenetic transformation towards quartz.

  3. Co-precipitation and solubility studies of cesium, potassium and sodium tetraphenylborate

    International Nuclear Information System (INIS)

    Peterson, R.A.

    2000-01-01

    This report contains the results from a study requested by High Level Waste on the co-precipitation and solubility of cesium, potassium, and sodium tetraphenylborate. Co-precipitation of cesium (Cs), potassium (K), and sodium (Na) tetraphenylborate (TPB) helps determine the efficiency of reagent usage in the Small Tank Precipitation Process. This process uses NaTPB to remove cesium from waste by means of precipitation. Previous studies by McCabe suggested that if the sodium ion concentration [Na + ] increased the rate at which cesium tetraphenylborate (CsTPB) precipitates also increases. Serkiz also demonstrated that the precipitation of potassium tetraphenylborate (KTPB) in the presence of high [Na + ] (∼5M) appears to produce a mixed solid phase composed of NaTPB and KTPB together in the crystal lattice. In the crystallographic structure of these three tetraphenylborate salts (Cs,K,NaTPB), the tetraphenylborate ion dominates the size of the crystals. Also, note that the three crystals have nearly identical structures with the exception of two additional peaks in the cesium pattern. Given these similarities, TPB precipitation in the presence of Na + , Cs + and K + likely produces an impure isomorphic crystalline mixture of CsTPB, KTPB and NaTPB. The authors speculate that the primary crystalline structure resembles that of KTPB with NaTPB and CsTPB mixed throughout the crystal structure. The precipitation of NaTPB makes some of the anticipated excess tetraphenylborate relatively unavailable for precipitation of cesium. Thus, the amount of excess tetraphenylborate required to completely precipitate all of the potassium and cesium may increase significantly

  4. Pulse frequency and soil-litter mixing alter the control of cumulative precipitation over litter decomposition.

    Science.gov (United States)

    Joly, François-Xavier; Kurupas, Kelsey L; Throop, Heather L

    2017-09-01

    Macroclimate has traditionally been considered the predominant driver of litter decomposition. However, in drylands, cumulative monthly or annual precipitation typically fails to predict decomposition. In these systems, the windows of opportunity for decomposer activity may rather depend on the precipitation frequency and local factors affecting litter desiccation, such as soil-litter mixing. We used a full-factorial microcosm experiment to disentangle the relative importance of cumulative precipitation, pulse frequency, and soil-litter mixing on litter decomposition. Decomposition, measured as litter carbon loss, saturated with increasing cumulative precipitation when pulses were large and infrequent, suggesting that litter moisture no longer increased and/or microbial activity was no longer limited by water availability above a certain pulse size. More frequent precipitation pulses led to increased decomposition at high levels of cumulative precipitation. Soil-litter mixing consistently increased decomposition, with greatest relative increase (+194%) under the driest conditions. Collectively, our results highlight the need to consider precipitation at finer temporal scale and incorporate soil-litter mixing as key driver of decomposition in drylands. © 2017 by the Ecological Society of America.

  5. Waste and Simulant Precipitation Issues

    International Nuclear Information System (INIS)

    Steele, W.V.

    2000-01-01

    As Savannah River Site (SRS) personnel have studied methods of preparing high-level waste for vitrification in the Defense Waste Processing Facility (DWPF), questions have arisen with regard to the formation of insoluble waste precipitates at inopportune times. One option for decontamination of the SRS waste streams employs the use of an engineered form of crystalline silicotitanate (CST). Testing of the process during FY 1999 identified problems associated with the formation of precipitates during cesium sorption tests using CST. These precipitates may, under some circumstances, obstruct the pores of the CST particles and, hence, interfere with the sorption process. In addition, earlier results from the DWPF recycle stream compatibility testing have shown that leaching occurs from the CST when it is stored at 80 C in a high-pH environment. Evidence was established that some level of components of the CST, such as silica, was leached from the CST. This report describes the results of equilibrium modeling and precipitation studies associated with the overall stability of the waste streams, CST component leaching, and the presence of minor components in the waste streams

  6. Effect of precipitation bias correction on water budget calculation in Upper Yellow River, China

    International Nuclear Information System (INIS)

    Ye Baisheng; Yang Daqing; Ma Lijuan

    2012-01-01

    This study quantifies the effect of precipitation bias corrections on basin water balance calculations for the Yellow River Source region (YRS). We analyse long-term (1959–2001) monthly and yearly data of precipitation, runoff, and ERA-40 water budget variables and define a water balance regime. Basin precipitation, evapotranspiration and runoff are high in summer and low in winter. The basin water storage change is positive in summer and negative in winter. Monthly precipitation bias corrections, ranging from 2 to 16 mm, do not significantly alter the pattern of the seasonal water budget. The annual bias correction of precipitation is about 98 mm (19%); this increase leads to the same amount of evapotranspiration increase, since yearly runoff remains unchanged and the long-term storage change is assumed to be zero. Annual runoff and evapotranspiration coefficients change, due to precipitation bias corrections, from 0.33 and 0.67 to 0.28 and 0.72, respectively. These changes will impact the parameterization and calibration of land surface and hydrological models. The bias corrections of precipitation data also improve the relationship between annual precipitation and runoff. (letter)

  7. Effects of different oxyanions in solution on the precipitation of jarosite at room temperature.

    Science.gov (United States)

    Yeongkyoo, Kim

    2018-04-09

    The effects of five different oxyanions, AsO 4 , SeO 3 , SeO 4 , MoO 4 , and CrO 4 , on the precipitation of jarosite at room temperature were investigated by X-ray diffraction, scanning electron microscopy, and chemical analysis. Different amounts (2, 5, and 10 mol%) of oxyanions in the starting solution and different aging times (1 h-40 days) were used for the experiment. In the initial stage, only the amorphous phase appears for all samples. With increasing aging time, jarosite and jarosite with oxyanions start precipitating at room temperature with different precipitation rates and crystallinities. Jarosite with AsO 4 shows the lowest precipitation rate and lowest crystallinity. With increasing amounts of oxyanions, the crystallization rate decreases, especially for jarosite with AsO 4 . The jarosite samples with CrO 4 and SeO 4 show the fastest precipitation and highest crystallinities. For the jarosite samples with a low precipitation rate and low crystallinity, the amorphous phase contains high concentrations of oxyanions, probably because of the fast precipitation of the amorphous iron oxyanion phase; however, the phase with fast jarosite precipitation contains fewer oxyanions. The results show that coprecipitation of jarosite can play a more important role in controlling the behavior of CrO 4 than AsO 4 in acid mine drainage. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Precipitation isoscapes for New Zealand: enhanced temporal detail using precipitation-weighted daily climatology.

    Science.gov (United States)

    Baisden, W Troy; Keller, Elizabeth D; Van Hale, Robert; Frew, Russell D; Wassenaar, Leonard I

    2016-01-01

    Predictive understanding of precipitation δ(2)H and δ(18)O in New Zealand faces unique challenges, including high spatial variability in precipitation amounts, alternation between subtropical and sub-Antarctic precipitation sources, and a compressed latitudinal range of 34 to 47 °S. To map the precipitation isotope ratios across New Zealand, three years of integrated monthly precipitation samples were acquired from >50 stations. Conventional mean-annual precipitation δ(2)H and δ(18)O maps were produced by regressions using geographic and annual climate variables. Incomplete data and short-term variation in climate and precipitation sources limited the utility of this approach. We overcome these difficulties by calculating precipitation-weighted monthly climate parameters using national 5-km-gridded daily climate data. This data plus geographic variables were regressed to predict δ(2)H, δ(18)O, and d-excess at all sites. The procedure yields statistically-valid predictions of the isotope composition of precipitation (long-term average root mean square error (RMSE) for δ(18)O = 0.6 ‰; δ(2)H = 5.5 ‰); and monthly RMSE δ(18)O = 1.9 ‰, δ(2)H = 16 ‰. This approach has substantial benefits for studies that require the isotope composition of precipitation during specific time intervals, and may be further improved by comparison to daily and event-based precipitation samples as well as the use of back-trajectory calculations.

  9. Controls on the meridional extent of tropical precipitation and its contraction under global warming

    Science.gov (United States)

    Donohoe, A.

    2017-12-01

    A method for decomposing changes and variability in the spatial structure of tropical precipitation into shifting (meridional translation), contracting, and intensifying modes of variability is introduced. We demonstrate that the shifting mode of tropical precipitation explains very little (20%) more of the tropical precipitation changes and variability. Furthermore, the contraction of tropical precipitation is highly correlated (R2 > 0.95) with an intensification of the precipitation in both the observations and forced modeled simulations. These results suggest that the simultaneous contraction and intensification of tropical precipitation is the dominant mode of variability and changes under external forcing. We speculate that tropical surface temperature controls this concurrent variability. Indeed, models robustly predict that tropical precipitation increases and meridionally contracts in response to increased CO2 and is reduced and meridionally expanded under glacial forcing and boundary conditions. In contrast, the directionality of the tropical precipitation shift is both ambiguous and small in magnitude in response to increased CO2. Furthermore, the ratio of the contraction/expansion to intensification/reduction is consistent in the continuum of climate states from the glacial climate to a modern climate to a 4XCO2 climate suggesting that the intensification and contraction are linked together via a single mechanism. We examine two mechanisms responsible for the contraction of the precipitation under global warming : i. the reduction of the seasonal cycle of energy input to the atmosphere due to sea ice retreat that results in the tropical precipitation remaining closer to the equator during the solsticial seasons and; ii. the increased gross moist stability of the tropical atmosphere as the surface warms resulting in a weaker cross-equatorial Hadley circulation during the solsticial seasons.

  10. Urbanization effect on precipitation over the Pearl River Delta based on CMORPH data

    Directory of Open Access Journals (Sweden)

    Sheng Chen

    2015-03-01

    Full Text Available Based on the satellite data from the Climate Prediction Center morphing (CMORPH at very high spatial and temporal resolution, the effects of urbanization on precipitation were assessed over the Pearl River Delta (PRD metropolitan regions of China. CMORPH data well estimates the precipitation features over the PRD. Compared to the surrounding rural areas, the PRD urban areas experience fewer and shorter precipitation events with a lower precipitation frequency (ratio of rainy hours, about 3 days per year less; however, short-duration heavy rain events play a more significant role over the PRD urban areas. Afternoon precipitation is much more pronounced over the PRD urban areas than the surrounding rural areas, which is probably because of the increase in short-duration heavy rain over urban areas.

  11. Dust and Biological Aerosols from the Sahara and Asia Influence Precipitation in the Western US

    Energy Technology Data Exchange (ETDEWEB)

    Creamean, Jessie; Suski, Kaitlyn; Rosenfeld, Daniel; Cazorla, Alberto; DeMott, Paul J.; Sullivan, Ryan C.; White, Allen B.; Ralph, F. M.; Minnis, Patrick; Comstock, Jennifer M.; Tomlinson, Jason M.; Prather, Kimberly

    2013-03-29

    Winter storms in California’s Sierra Nevada increase seasonal snowpack and provide critical water resources for the state. Thus, the mechanisms influencing precipitation in this region have been the subject of research for decades. Previous studies suggest Asian dust enhances cloud ice and precipitation (1), while few studies consider biological aerosols as an important global source of ice nuclei (IN). Here, we show that dust and biological aerosols transported from as far as the Sahara were present in glaciated high-altitude clouds coincident with elevated IN concentrations and ice-induced precipitation. This study presents the first direct cloud and precipitation measurements showing that Saharan and Asian dust and biological aerosols likely serve as IN and play an important role in orographic precipitation processes over the western United States.

  12. Effects of large-scale deforestation on precipitation in the monsoon regions: remote versus local effects.

    Science.gov (United States)

    Devaraju, N; Bala, Govindasamy; Modak, Angshuman

    2015-03-17

    In this paper, using idealized climate model simulations, we investigate the biogeophysical effects of large-scale deforestation on monsoon regions. We find that the remote forcing from large-scale deforestation in the northern middle and high latitudes shifts the Intertropical Convergence Zone southward. This results in a significant decrease in precipitation in the Northern Hemisphere monsoon regions (East Asia, North America, North Africa, and South Asia) and moderate precipitation increases in the Southern Hemisphere monsoon regions (South Africa, South America, and Australia). The magnitude of the monsoonal precipitation changes depends on the location of deforestation, with remote effects showing a larger influence than local effects. The South Asian Monsoon region is affected the most, with 18% decline in precipitation over India. Our results indicate that any comprehensive assessment of afforestation/reforestation as climate change mitigation strategies should carefully evaluate the remote effects on monsoonal precipitation alongside the large local impacts on temperatures.

  13. Meta-analysis : High-dosage vitamin E supplementation may increase all-cause mortality

    NARCIS (Netherlands)

    Miller, ER; Pastor-Barriuso, R; Dalal, D; Riemersma, RA; Appel, LJ; Guallar, E

    2005-01-01

    Background: Experimental models and observational studies suggest that vitamin E supplementation may prevent cardiovascular disease and cancer. However, several trials of high-dosage vitamin E supplementation showed non-statistically significant increases in total mortality. Purpose: To perform a

  14. Do increases in cigarette prices lead to increases in sales of cigarettes with high tar and nicotine yields?

    Science.gov (United States)

    Farrelly, Matthew C; Loomis, Brett R; Mann, Nathan H

    2007-10-01

    We used scanner data on cigarette prices and sales collected from supermarkets across the United States from 1994 to 2004 to test the hypothesis that cigarette prices are positively correlated with sales of cigarettes with higher tar and nicotine content. During this period the average inflation-adjusted price for menthol cigarettes increased 55.8%. Price elasticities from multivariate regression models suggest that this price increase led to an increase of 1.73% in sales-weighted average tar yields and a 1.28% increase in sales-weighted average nicotine yields for menthol cigarettes. The 50.5% price increase of nonmenthol varieties over the same period yielded an estimated increase of 1% in tar per cigarette but no statistically significant increase in nicotine yields. An ordered probit model of the impact of cigarette prices on cigarette strength (ultra-light, light, full flavor, unfiltered) offers an explanation: As cigarette prices increase, the probability that stronger cigarette types will be sold increases. This effect is larger for menthol than for nonmenthol cigarettes. Our results are consistent with earlier population-based cross-sectional and longitudinal studies showing that higher cigarette prices and taxes are associated with increasing consumption of higher-yield cigarettes by smokers.

  15. Chronic high-sucrose diet increases fibroblast growth factor 21 production and energy expenditure in mice.

    Science.gov (United States)

    Maekawa, Ryuya; Seino, Yusuke; Ogata, Hidetada; Murase, Masatoshi; Iida, Atsushi; Hosokawa, Kaori; Joo, Erina; Harada, Norio; Tsunekawa, Shin; Hamada, Yoji; Oiso, Yutaka; Inagaki, Nobuya; Hayashi, Yoshitaka; Arima, Hiroshi

    2017-11-01

    Excess carbohydrate intake causes obesity in humans. On the other hand, acute administration of fructose, glucose or sucrose in experimental animals has been shown to increase the plasma concentration of anti-obesity hormones such as glucagon-like peptide 1 (GLP-1) and Fibroblast growth factor 21 (FGF21), which contribute to reducing body weight. However, the secretion and action of GLP-1 and FGF21 in mice chronically fed a high-sucrose diet has not been investigated. To address the role of anti-obesity hormones in response to increased sucrose intake, we analyzed mice fed a high-sucrose diet, a high-starch diet or a normal diet for 15 weeks. Mice fed a high-sucrose diet showed resistance to body weight gain, in comparison with mice fed a high-starch diet or control diet, due to increased energy expenditure. Plasma FGF21 levels were highest among the three groups in mice fed a high-sucrose diet, whereas no significant difference in GLP-1 levels was observed. Expression levels of uncoupling protein 1 (UCP-1), FGF receptor 1c (FGFR1c) and β-klotho (KLB) mRNA in brown adipose tissue were significantly increased in high sucrose-fed mice, suggesting increases in FGF21 sensitivity and energy expenditure. Expression of carbohydrate responsive element binding protein (ChREBP) mRNA in liver and brown adipose tissue was also increased in high sucrose-fed mice. These results indicate that FGF21 production in liver and brown adipose tissue is increased in high-sucrose diet and participates in resistance to weight gain. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  16. High hydrogen loading of thin palladium wires through alkaline earth carbonates' precipitation on the cathodic surface - evidence of a new phase in the Pd-H system

    Energy Technology Data Exchange (ETDEWEB)

    Celani, F.; Spallone, A.; Di Gioacchino, D. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Frascati, RM (Italy); Marini, P.; Di Stefano, V.; Nakamura, M. [EURESYS, Rome (Italy); Pace, S. [Salerno Univ., Salerno (Italy). Dept. of Physics, Istituto Nazionale per la Fisica della Materia; Mancini, A. [ORIM S.r.l., Piediripa, MC (Italy); Tripodi, P. [Stanford Research Institut International, Stanford, CA (United States)

    2000-07-01

    A new protocol for the electrolytic loading of hydrogen (H) in thin palladium (Pd) wires has been developed. In order to increase the cathodic overvoltage, which is known to be the main parameter capable to enhance the electrolytic H loading of Pd, the catalytic action of the Pd surface versus H-H recombination has been strongly reduced by precipitation of a thin layer of alkaline-earth carbonates on the cathode. A set of electrolytes has been employed, containing small amounts of hydrochloric or sulfuric acid and strontium or calcium ions. The H loading has been continuously evaluated through ac measurements of the Pd wire resistance. Uncommonly low resistivity values, leading to an estimate of exceptionally high H loading, have been observed. Evidence of the existence of a new phase in the very high H content region of the Pd-H system has been inferred on the basis of the determination of the temperature coefficient of the electrical resistivity. Mainly for this purpose a thin layer of Hg was galvanically deposed on the cathodic surface, in order to prevent any H deloading during the measurements. The results have been fully reproduced in other 2 well equipped and experienced Laboratories (Italy, USA).

  17. Moderate high fat diet increases sucrose self-administration in young rats.

    Science.gov (United States)

    Figlewicz, Dianne P; Jay, Jennifer L; Acheson, Molly A; Magrisso, Irwin J; West, Constance H; Zavosh, Aryana; Benoit, Stephen C; Davis, Jon F

    2013-02-01

    We have previously reported that a moderately high fat diet increases motivation for sucrose in adult rats. In this study, we tested the motivational, neurochemical, and metabolic effects of the high fat diet in male rats transitioning through puberty, during 5-8 weeks of age. We observed that the high fat diet increased motivated responding for sucrose, which was independent of either metabolic changes or changes in catecholamine neurotransmitter metabolites in the nucleus accumbens. However, AGRP mRNA levels in the hypothalamus were significantly elevated. We demonstrated that increased activation of AGRP neurons is associated with motivated behavior, and that exogenous (third cerebroventricular) AGRP administration resulted in significantly increased motivation for sucrose. These observations suggest that increased expression and activity of AGRP in the medial hypothalamus may underlie the increased responding for sucrose caused by the high fat diet intervention. Finally, we compared motivation for sucrose in pubertal vs. adult rats and observed increased motivation for sucrose in the pubertal rats, which is consistent with previous reports that young animals and humans have an increased preference for sweet taste, compared with adults. Together, our studies suggest that background diet plays a strong modulatory role in motivation for sweet taste in adolescent animals. Published by Elsevier Ltd.

  18. Overcoming barriers to increased bio-energy use. Suggestions for a high impact policy

    International Nuclear Information System (INIS)

    Chanakya, H.N.; Ravindranath, N.H.

    1997-01-01

    A few options that are likely to result in a high impact policy towards ensuring increased use of bio-energy in the developing world are discussed. Such options are: Moving towards greater energy security /guarantee, bio-energy technology transfer platforms, documentation in bio-energy businesses, removing risk perceptions in financing, increasing private entrepreneur stakes, etc. (K.A.)

  19. The choice of strategic alternatives under increasing regulation in high technology companies.

    Science.gov (United States)

    Birnbaum, P H

    1984-09-01

    The strategic response of U.S. high technology companies in the medical X-ray manufacturing industry to increased governmental regulations from 1962 to 1977 is examined. Results suggest that regulations increase consumer and competitor uncertainty, with the consequence that firms select less risky strategies and decrease the riskier new product invention strategy. Larger firms reduce inventions less than smaller firms.

  20. Rheology of tetraphenylborate precipitate slurry

    International Nuclear Information System (INIS)

    Goren, I.D.; Martin, H.D.; McLain, M.A.

    1985-01-01

    The rheological properties of tetraphenylborate precipitate slurry were determined. This nonradioactive slurry simulates the radioactive tetraphenylborate precipitate generated at the Savannah River Plant by the In-Tank Precipitation Process. The data obtained in this study was applied in the design of slurry pumps, transfer pumps, transfer lines, and vessel agitation for the Defense Waste Processing Facility and other High Level Waste treatment projects. The precipitate slurry behaves as a Bingham plastic. The yield stress is directly proportional to the concentration of insoluble solids over the range of concentrations studied. The consistency is also a linear function of insoluble solids over the same concentration range. Neither the yield stress nor the consistency was observed to be affected by the presence of the soluble solids. Temperature effects on flow properties of the slurry were also examined: the yield stress is inversely proportional to temperature, but the consistency of the slurry is independent of temperature. No significant time-dependent effects were found. 4 refs., 4 figs., 3 tabs

  1. Effective application of freezing lipid precipitation and SCX-SPE for determination of pyrrolizidine alkaloids in high lipid foodstuffs by LC-ESI-MS/MS.

    Science.gov (United States)

    Yoon, Soo Hwan; Kim, Min-Sun; Kim, Sang Hoon; Park, Hyun Mee; Pyo, Heesoo; Lee, Yong Moon; Lee, Kyung-Tae; Hong, Jongki

    2015-06-15

    Pyrrolizidine alkaloids (PAs) are naturally occurring plant toxins associated with serious hepatic disease in humans and animals. In this study, rapid and sensitive analytical method was developed for the determination of 9 toxic PAs in popularly high lipid foodstuffs by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). PAs in lipid foodstuff were effectively purified by freezing lipid precipitation (FLP) and strong cation exchange (SCX)-solid-phase extraction (SPE). Especially, FLP could easily remove the large amounts of triacylglycerols in the lipid sample extract and effectively combine with SPE cleanup. During the FLP procedure, over 77% of the lipids in the foodstuff extracts were rapidly eliminated without any significant loss of the PAs with over 81% recovery. The elimination efficiency of lipids by FLP was tested with LC-atmospheric chemical ionization (APCI)-MS. For further purification, SCX-SPE cartridge could successfully purify PAs from the remaining interfering substances by the variation pH with 5% NH4OH in methanol. For precise quantification and confirmation of PAs in complicate sample matrices, appropriate transition ions in LC-MS/MS-multiple-ion reaction monitoring (MRM) mode were selected on the basis of MS/MS fragmentation pathways of PAs. The established analytical method was validated in terms of the linearity, limits of detection (LOD), and quantification (LOQ), precision, and accuracy. The method was deemed satisfactory by inter- and intra-day validation and exhibited both high accuracy and precision (relative standard deviation<11.06%). Overall limits of detection and quantitation of PAs were approximately 0.06-0.60ng/mL at a signal-to-noise ratio (S/N) of 3 and were about 0.20-1.99ng/mL at a S/N of 10 for all foodstuffs. The established method was successfully applied for the monitoring of toxic PAs in several types of high lipid foodstuffs such as soybeans, seed oil, milk, and margarine. Copyright

  2. Increasing High School Students' Interest in STEM Education through Collaborative Brainstorming with Yo-Yos

    Science.gov (United States)

    Fang, Ning

    2013-01-01

    Brainstorming is a creativity technique in which a group of people (or an individual person) spontaneously generates a set of ideas to find the solution to a particular problem. This paper describes an innovative approach called "brainstorming with yo-yos," which was implemented in an outreach to high school event to increase high school…

  3. High intensity interior aircraft noise increases the risk of high diastolic blood pressure in Indonesian Air Force pilots

    Directory of Open Access Journals (Sweden)

    Minarma Siagian

    2009-12-01

    Full Text Available Aim: To analyze the effects of aircraft noise, resting pulse rate, and other factors on the risk of high diastolic blood pressure (DBP in Indonesian Air Force pilots.Methods: A nested case-control study was conducted using data extracted from annual medical check-ups indoctrination aerophysiologic training records at the Saryanto Aviation and Aerospace Health Institute (LAKESPRA in Jakarta from January 2003 – September 2008. For analysis of DBP: the case group with DBP ≥ 90 mmHg were compared with contral group with DBP < 79 mmHG. One case matched to 12 controls.Results: Out of 567 pilots, 544 (95.9% had complete medical records. For this analysis there were 40 cases of high DBP and 480 controls for DBP. Pilots exposed to aircraft noise 90-95 dB rather than 70-80 dB had a 2.7-fold increase for high DBP [adjusted odds ratio (ORa = 2.70; 95% confi dence interval (CI = 1.05-6.97]. Pilots with resting pulse rates of ≥ 81/minute rather than ≤ 80/minute had a 2.7-fold increase for high DBP (ORa = 2.66; 95% CI = 1.26-5.61. In terms of total fl ight hours, pilots who had 1401-11125 hours rather than 147-1400 hours had a 3.2-fold increase for high DBP (ORa = 3.18; 95% CI = 1.01-10.03.Conclusion: High interior aircraft noise, high total flight hours,  and high resting pulse rate, increased risk for high DBP. Self assessment of resting pulse rate can be used to control the risk of high DBP. (Med J Indones 2009; 276: 276-82Keywords: diastolic blood pressure, aircraft noise, resting pulse rate, military pilots

  4. Precipitation in a warming world: Assessing projected hydro-climate changes in California and other Mediterranean climate regions.

    Science.gov (United States)

    Polade, Suraj D; Gershunov, Alexander; Cayan, Daniel R; Dettinger, Michael D; Pierce, David W

    2017-09-07

    In most Mediterranean climate (MedClim) regions around the world, global climate models (GCMs) consistently project drier futures. In California, however, projections of changes in annual precipitation are inconsistent. Analysis of daily precipitation in 30 GCMs reveals patterns in projected hydrometeorology over each of the five MedClm regions globally and helps disentangle their causes. MedClim regions, except California, are expected to dry via decreased frequency of winter precipitation. Frequencies of extreme precipitation, however, are projected to increase over the two MedClim regions of the Northern Hemisphere where projected warming is strongest. The increase in heavy and extreme precipitation is particularly robust over California, where it is only partially offset by projected decreases in low-medium intensity precipitation. Over the Mediterranean Basin, however, losses from decreasing frequency of low-medium-intensity precipitation are projected to dominate gains from intensifying projected extreme precipitation. MedClim regions are projected to become more sub-tropical, i.e. made dryer via pole-ward expanding subtropical subsidence. California's more nuanced hydrological future reflects a precarious balance between the expanding subtropical high from the south and the south-eastward extending Aleutian low from the north-west. These dynamical mechanisms and thermodynamic moistening of the warming atmosphere result in increased horizontal water vapor transport, bolstering extreme precipitation events.

  5. Increased effects of machining damage in beryllium observed at high strain rates

    International Nuclear Information System (INIS)

    Beitscher, S.; Brewer, A.W.; Corle, R.R.

    1980-01-01

    Tensile tests at both low and high strain rates, and also impact shear tests, were performed on a weldable grade powder-source beryllium. Impact energies increased by a factor of 2 to 3 from the as-machined level after etching or annealing. Similar increases in the ductility from machining damage removal were observed from the tensile data at the higher strain rate (10 s -1 ) while an insignificant increase in elongation was measured at the lower strain rate (10 -4 s -1 ). High strain-rate tests appear to be more sensitive and reliable for evaluating machining practice and damage removal methods for beryllium components subjected to sudden loads. 2 tables

  6. Thiamine and benfotiamine prevent increased apoptosis in endothelial cells and pericytes cultured in high glucose.

    Science.gov (United States)

    Beltramo, E; Berrone, E; Buttiglieri, S; Porta, M

    2004-01-01

    High glucose induces pathological alterations in small and large vessels, possibly through increased formation of AGE, activation of aldose reductase and protein kinase C, and increased flux through the hexosamine pathway. We showed previously that thiamine and benfotiamine correct delayed replication and increase lactate production in endothelial cells subjected to high glucose. We now aim at verifying the effects of thiamine and benfotiamine on cell cycle, apoptosis, and expression of adhesion molecules in endothelial cells and pericytes, under high ambient glucose. Human umbilical vein endothelial cells and bovine retinal pericytes were cultured in normal (5.6 mmol/L) or high (28 mmol/L) glucose, with or without thiamine or benfotiamine, 50 or 100 micro mol/L. Apoptosis was determined by two separate ELISA methods, measuring DNA fragmentation and caspase-3 activity, respectively. Cell cycle and integrin subunits alpha3, alpha5, and beta1 concentration were measured by flow cytometry. Apoptosis was increased in high glucose after 3 days of culture, both in endothelium and pericytes. Thiamine and benfotiamine reversed such effects. Neither cell cycle traversal nor integrin concentrations were modified in these experimental conditions. Thiamine and benfotiamine correct increased apoptosis due to high glucose in cultured vascular cells. Further elucidations of the mechanisms through which they work could help set the basis for clinical use of this vitamin in the prevention and/or treatment of diabetic microangiopathy. Copyright 2004 John Wiley & Sons, Ltd.

  7. Tree ring evidence of a 20th century precipitation surge in the monsoon shadow zone of the western Himalaya, India

    Science.gov (United States)

    Yadav, Ram R.

    2011-01-01

    The present study is the first attempt to develop an annual (August-July) precipitation series back to AD 1330 using a tree ring data network of Himalayan cedar (Cedrus deodara (Roxb.) G. Don) from the Lahaul-Spiti region in the western Himalaya, India. The rainfall reconstruction reveals high magnitude multidecadal droughts during the 14th and 15th centuries and thenceforth a gradual increase in precipitation. Increasingly wet conditions during the 20th century are consistent with other long-term precipitation reconstructions from high Asia and reflect a large-scale intensification of the hydrological cycle, coincident with what is anticipated due to global warming. Significant relationships between reconstructed precipitation and precipitation records from central southwest Asia, east of the Caspian Sea, ENSO (NINO4-SST) variability and summer monsoon rainfall over central northeast India underscore the utility of our data in synoptic climatology.

  8. Precipitation behaviors of X70 acicular ferrite pipeline steel

    Institute of Scientific and Technical Information of China (English)

    Hao Yu; Yi Sun; Qixiang Chen; Haitao Jiang; Lihong Zhang

    2006-01-01

    The morphology, structure, and chemical composition of precipitates in the final microstructure of Nb-V-Ti microalloyed X70 acicular ferrite pipeline steel were investigated using transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). Precipitates observed by TEM can be classified into two groups. The large precipitates are complex compounds that comprise square-shaped TiN precipitate as core with fine Nb-containing precipitate nucleated on pre-existing TiN precipitate as caps on one or more faces at high temperature. In contrast, the fine and spherical Nb carbides and/or carbonitrides precipitate heterogeneously on dislocations and sub-boundaries at low temperature. From the analysis in terms of thermodynamics, EDS and chemical composition of the steel, NbC precipitation is considered to be the predominant precipitation behavior in the tested steel under the processing conditions of this research.

  9. Linkages between Icelandic Low position and SE Greenland winter precipitation

    Science.gov (United States)

    Berdahl, M.; Rennermalm, A. K.; Hammann, A. C.; Mioduszewski, J.; Hameed, S.; Tedesco, M.; Stroeve, J. C.; Mote, T. L.

    2015-12-01

    Greenland's largest flux of precipitation occurs in its Southeast (SE) region. An understanding of the mechanisms controlling precipitation in this region is lacking despite its disproportionate importance in the mass balance of Greenland and the consequent contributions to sea level rise. We use weather station data from the Danish Meteorological Institute to reveal the governing influences on precipitation in SE Greenland during the winter and fall. We find that precipitation in the fall is significantly correlated to the longitude of the Icelandic Low and the NAO. Winter precipitation is correlated with the strength and longitude of the Icelandic Low, as well as the NAO. We show that in years of extreme high precipitation, onshore winds dominate, thereby advecting more moisture inland. In low precipitation years, winds are more westerly, approaching the stations from land. Understanding the controls of SE Greenland precipitation will help us predict how future precipitation in this key region may change in a warming climate.

  10. WPA Precipitation Tabulations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hourly precipitation data tabulated under the Work Projects Administration (WPA), a New Deal program created to reduce unemployment during the Great Depression....

  11. Stress corrosion cracking of stainless steels under deaerated high-temperature water. Influence of grain boundary carbide precipitation, and effect of Mo and Cr in alloys

    International Nuclear Information System (INIS)

    Yamada, Takuyo; Terachi, Takumi; Miyamoto, Tomoki; Arioka, Koji

    2007-01-01

    In order to evaluate the influence of grain boundary carbide on IGSCC susceptibility of stainless steel, crack growth rate tests were performed under deaerated or 0.3 ppm hydrogenated pure water environments at 320degC using half-inch compact tension (CT) specimens. In our previous report, CT testing showed that the susceptibility of CW316 to IGSCC was inhibited by the precipitation of grain boundary carbide under these environments. The result suggested quite different behavior from that in an oxygenated high-temperature water environment. In this study, the influence of (1) Mo and (2) Cr content in alloys, and (3) Cr depletion at the grain boundary on the IGSCC growth behavior in stainless steel was studied at 320degC under a 0.3-ppm hydrogenated pure-water environment. As a result, (1) IGSCC growth was observed on non-sensitized CW20%316, CW20%304, CW20%20Cr316, and CW20%20Cr304 under a 0.3-ppm hydrogenated pure-water environment at 320degC. (2) IGSCC growth was not observed for sensitized CW20%316 and CW20%304 (at 650degC x 48 or 24 h) and healing heat-treated CW20%316 (at 650degC x 48 h + 900degC x 0.5 h) under the same water environment. (3) The susceptibility of high Cr content materials (CW20%20Cr316 and CW20% 20Cr304) to IGSCC resistance was improved that of conventional CW316 and CW304 under the same water environment. The higher Cr content is effective in inhibiting susceptibility to IGSCC, but the inhibiting effect of Cr content is smaller than the effect of the grain boundary carbide. (4) These differences in IGSCC suggest that grain boundary carbide has a beneficial effect in improving IGSCC resistance, at least in a 0.3-ppm hydrogenated pure-water environment, despite the Mo content and Cr depletion at grain boundary. (author)

  12. Climate change and precipitation: Detecting changes Climate change and precipitation: Detecting changes

    International Nuclear Information System (INIS)

    Van Boxel, John H

    2001-01-01

    Precipitation is one of the most, if not the most important climate parameter In most studies on climate change the emphasis is on temperature and sea level rise. Often too little attention is given to precipitation. For a large part this is due to the large spatial en temporal variability of precipitation, which makes the detection of changes difficult. This paper describes methods to detect changes in precipitation. In order to arrive at statistically significant changes one must use long time series and spatial averages containing the information from several stations. In the Netherlands the average yearly precipitation increased by 11% during the 20th century .In the temperate latitudes on the Northern Hemisphere (40-60QN) the average increase was about 7% over the 20th century and the globally averaged precipitation increased by about 3%. During the 20th century 38% of the land surface of the earth became wetter, 42% experienced little change (less than 5% change) and 20% became dryer. More important than the average precipitation is the occurrence of extremes. In the Netherlands there is a tendency to more extreme precipitations, whereas the occurrence of relatively dry months has not changed. Also in many other countries increases in heavy precipitation events are observed. All climate models predict a further increase of mean global precipitation if the carbon dioxide concentration doubles. Nevertheless some areas get dryer, others have little change and consequently there are also areas where the increase is much more than the global average. On a regional scale however there are large differences between the models. Climate models do not yet provide adequate information on changes in extreme precipitations

  13. Study of asphaltene precipitation by Calorimetry

    DEFF Research Database (Denmark)

    Verdier, Sylvain Charles Roland; Plantier, Frédéric; Bessières, David

    2007-01-01

    Can calorimetry bring new input to the Current understanding of asphaltene precipitation? In this work, two types of precipitation were studied by means of calorimetry: addition of n-heptane into asphaltene solutions and temperature/pressure variations on a recombined live oil. The first series...... of experiments showed that weak forces determine precipitation. Indeed, isothermal titration calorimetry could not detect any clear signal although this technique can detect low-energy transitions such as liquid-liquid equilibrium and rnicellization. The second series of tests proved that precipitation caused...... by T and P variations is exothermic for this system. Furthermore, the temperature-induced precipitation is accompanied by an increase in the apparent thermal expansivity. Therefore, it seems that these two phase transitions exhibit different calorimetric behaviours and they may not be as similar...

  14. Electrostatic precipitators for coal thermal power plants energized by means of narrow pulse voltage

    Energy Technology Data Exchange (ETDEWEB)

    Dinelli, G.; Mattachini, F.; Bogani, V.; Baldacci, A.; Tarli, R. (ENEL-CRTN, Direzione Studi e Ricerche, Milan (Italy) ENEL, VDT Settore Tecnico, Direzione Produzione e Trasmissione, Rome (Italy))

    1990-09-01

    The efficiency of electrostatic precipitators, widely used in thermal power plants to clean flue gases from solid particulate, is strongly dependent both on the way particles are electrically charged and on the characteristics of the electric field within the interelectrodic space of the precipitator. Such operating may become inadequate under varying particle characteristics and operating conditions of the thermal plant, therefore bringing to a reduction in the precipitator collection efficiency. An innovative technique, by generating a pulsed corona in the precipitator, allows a substantial improvement of both the particle charging and the collection processes and an increase in the operation flexibility of the electrostatic precipitator. The narrow pulse voltage energization has been extensively tested at a coal thermal unit having the electrostatic precipitators equipped with both conventional and pulse power sets. The long duration tests confirmed the following results: 1) high reliability of the pulse power sets and a considerable improvement in the precipitator collection efficiency; 2) a decrease in the particulate emissions, with coals whose ashes are of difficult collection, ranging between 75% and 85% of those with conventional energization; 3) a reduction by a factor of about 5 in the consumption of electric power by the electrostatic precipitation process.

  15. Future changes in Asian summer monsoon precipitation extremes as inferred from 20-km AGCM simulations

    Science.gov (United States)

    Lui, Yuk Sing; Tam, Chi-Yung; Lau, Ngar-Cheung

    2018-04-01

    This study examines the impacts of climate change on precipitation extremes in the Asian monsoon region during boreal summer, based on simulations from the 20-km Meteorological Research Institute atmospheric general circulation model. The model can capture the summertime monsoon rainfall, with characteristics similar to those from Tropical Rainfall Measuring Mission and Asian Precipitation-Highly-Resolved Observational Data Integration Towards Evaluation. By comparing the 2075-2099 with the present-day climate simulations, there is a robust increase of the mean rainfall in many locations due to a warmer climate. Over southeastern China, the Baiu rainband, Bay of Bengal and central India, extreme precipitation rates are also enhanced in the future, which can be inferred from increases of the 95th percentile of daily precipitation, the maximum accumulated precipitation in 5 consecutive days, the simple daily precipitation intensity index, and the scale parameter of the fitted gamma distribution. In these regions, with the exception of the Baiu rainband, most of these metrics give a fractional change of extreme rainfall per degree increase of the lower-tropospheric temperature of 5 to 8.5% K-1, roughly consistent with the Clausius-Clapeyron relation. However, over the Baiu area extreme precipitation change scales as 3.5% K-1 only. We have also stratified the rainfall data into those associated with tropical cyclones (TC) and those with other weather systems. The AGCM gives an increase of the accumulated TC rainfall over southeastern China, and a decrease in southern Japan in the future climate. The latter can be attributed to suppressed TC occurrence in southern Japan, whereas increased accumulated rainfall over southeastern China is due to more intense TC rain rate under global warming. Overall, non-TC weather systems are the main contributor to enhanced precipitation extremes in various locations. In the future, TC activities over southeastern China tend to further

  16. Formation of copper precipitates in silicon

    Science.gov (United States)

    Flink, Christoph; Feick, Henning; McHugo, Scott A.; Mohammed, Amna; Seifert, Winfried; Hieslmair, Henry; Heiser, Thomas; Istratov, Andrei A.; Weber, Eicke R.

    1999-12-01

    The formation of copper precipitates in silicon was studied after high-temperature intentional contamination of p- and n-type FZ and Cz-grown silicon and quench to room temperature. With the Transient Ion Drift (TID) technique on p-type silicon a critical Fermi level position at EC-0.2 eV was found. Only if the Fermi level position, which is determined by the concentrations of the acceptors and the copper donors, surpasses this critical value precipitation takes place. If the Fermi level is below this level the supersaturated interstitial copper diffuses out. An electrostatic precipitation model is introduced that correlates the observed precipitation behavior with the electrical activity of the copper precipitates as detected with Deep Level Transient Spectroscopy (DLTS) on n-type and with Minority Carrier Transient Spectroscopy (MCTS) on p-type silicon.

  17. High trees increase sunflower seed predation by birds in an agricultural landscape of Israel

    Directory of Open Access Journals (Sweden)

    Jessica eSchäckermann

    2014-07-01

    Full Text Available Natural habitats in agricultural landscapes promote agro-ecosystem services but little is known about negative effects (dis-services derived by natural habitats such as crop seed predation. Birds are important seed predators and use high landscape structures to perch and hide. High trees in agricultural landscapes may therefore drive seed predation. We examined if the presence, the distance and the percentages of high trees (tree height >5 m and the percentages of natural habitat surrounding sunflower fields, increased seed predation by birds in Israel. At the field scale, we assessed seed predation across a sample grid of an entire field. At the landscape scale, we assessed seed predation at the field margins and interiors of 20 sunflower fields. Seed predation was estimated as the percentage of removed seeds from sunflower heads. Distances of sample points to the closest high tree and percentage of natural habitat and of high trees in a 1km radius surrounding the fields were measured.We found that seed predation increased with decreasing distance to the closest high tree at the field and landscape scale. At the landscape scale, the percentage of high trees and natural habitat did not increase seed predation. Seed predation in the fields increased by 37 %, with a maximum seed predation of 92 %, when a high tree was available within zero to 50 m to the sunflower fields. If the closest high tree was further away, seed predation was less than 5 %. Sunflower seed predation by birds can be reduced, when avoiding sowing sunflowers within a radius of 50 m to high trees. Farmers should plan to grow crops, not sensitive to bird seed predation, closer to trees to eventually benefit from ecosystem services provided by birds, such as predation of pest insects, while avoiding these locations for growing crops sensitive to bird seed predation. Such management recommendations are directing towards sustainable agricultural landscapes.

  18. On the importance of specific heats as regards efficiency increases for highly dilute IC engines

    International Nuclear Information System (INIS)

    Caton, Jerald A.

    2014-01-01

    Highlights: • Importance of specific heats towards increasing engine efficiency was quantified. • Decreases of specific heats contribute 3.5–6.3% (abs) to the efficiency. • Dilute engines benefit from decreases of specific heats due to lower temperatures. - Abstract: Engineering and scientific efforts continue with the development of advanced, IC engines using highly dilute mixtures, and relatively high compression ratios. Such engines are known to provide opportunities for low emissions as well as high efficiencies. The main features of these engines include higher compression ratios, lean operation, use of EGR, and shorter burn durations. First, this study reviews the quantitative contributions of each of these features as determined by an engine cycle simulation. Second, this study provides the quantitative contributions to the increased efficiency in terms of fundamental thermodynamic considerations. An automotive engine operated at 2000 rpm was selected for this study. For the conditions examined, the net indicated thermal efficiency increased from 37.0% (conventional engine) to 53.9% (high efficiency engine) – for an incremental increase of 16.9% (absolute). The contribution of increases of the ratio of specific heats towards the final thermal efficiency is qua