WorldWideScience

Sample records for acid precipitation assessment

  1. Acid Precipitation

    Science.gov (United States)

    Likens, Gene E.

    1976-01-01

    Discusses the fact that the acidity of rain and snow falling on parts of the U.S. and Europe has been rising. The reasons are still not entirely clear and the consequences have yet to be well evaluated. (MLH)

  2. National Acid Precipitation Assessment Program Report to Congress: An Integrated Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Uhart, M.; et al,

    2005-08-01

    Under Title IX of the 1990 Clean Air Act Amendments, Congress reauthorized the National Acid Precipitation Assessment Program (NAPAP) to continue coordinating acid rain research and monitoring, as it had done during the previous decade, and to provide Congress with periodic reports. In particular, Congress asked NAPAP to assess all available data and information to answer two questions: (1) What are the costs, benefits, and effectiveness of Title IV? This question addresses the costs and economic impacts of complying with the Acid Rain Program as well as benefit analyses associated with the various human health and welfare effects, including reduced visibility, damages to materials and cultural resources, and effects on ecosystems. (2) What reductions in deposition rates are needed to prevent adverse ecological effects? This complex questions addresses ecological systems and the deposition levels at which they experience harmful effects. The results of the assessment of the effects of Title IV and of the relationship between acid deposition rates and ecological effects were to be reported to Congress quadrennially, beginning with the 1996 report to Congress. The objective of this Report is to address the two main questions posed by Congress and fully communicate the results of the assessment to decision-makers. Given the primary audience, most of this report is not written as a technical document, although information supporting the conclusions is provided along with references.

  3. Quantifying foliar responses of white ash to ozone and simulated acid precipitation: an assessment proposal for forest exposure studies

    Science.gov (United States)

    Leon S. Dochinger; Keith F. Jensen; Keith F. Jensen

    1990-01-01

    Seedlings represent an important linkage for assessing the effect of air pollution on forests. This study examines the foliar responses of white ash seedlings to ozone and acid precipitation as a means of identifying atmospheric deposition effects on forests.

  4. National Acid Precipitation Assessment Program Report to Congress: An integrated assessment

    Science.gov (United States)

    Burns, Douglas A.; Fenn, Mark E.; Baron, Jill S.; Lynch, Jason A.; Cosby, Bernard J.

    2011-01-01

    Acid deposition, more commonly known as acid rain, occurs when emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) react in the atmosphere with water, oxygen, and oxidants to form various acidic compounds. Prevailing winds transport the acidic compounds hundreds of miles, often across state and national borders. These acidic compounds then fall to earth in either a wet form (rain, snow, and fog) or a dry form (gases, aerosols, and particles). At certain levels, the acidic compounds, including small particles such as sulfates and nitrates, can cause many negative human health and environmental effects.

  5. Acid precipitation and forest soils

    Science.gov (United States)

    C. O. Tamm

    1976-01-01

    Many soil processes and properties may be affected by a change in chemical climate such as that caused by acidification of precipitation. The effect of additions of acid precipitation depends at first on the extent to which this acid is really absorbed by the soil and on the changes in substances with actual or potential acidity leaving the soil. There is for instance...

  6. Development and Preliminary Assessment of Hemoperfusion Cartridge with Tannic Acid for Toxic Proteins' Precipitation: An In Vitro Model

    Directory of Open Access Journals (Sweden)

    Valquíria Miwa Hanai Yoshida

    2016-09-01

    Full Text Available Charcoal hemoperfusion (CHP is one of the extracorporeal removal techniques that are used to remove toxins from the body. CHP generally is considered the preferred method for extracorporeal extraction of several toxins—toxins that are adsorbed by activated charcoal. Assessments of the tannic acid's protective effects on ophidian poisoning are associated with the toxic proteins' precipitation by tannic acid. The challenge in treating a snakebite lies in removing the injected poison with minimal damage to blood constituent proteins. An alternative is CHP, and this investigation proposed to develop a column for hemoperfuser cartridge, combining charcoal granules trapped between layers of polymeric material conjugated to tannic acid, using an in vitro model scaled to the Wistar rat, which can be tested in an animal model. The cartridge was evaluated using the 22 full factorial design, in duplicate, as a method to study the effects of granulated-charcoal size and tannic acid concentration on the hematologic profile (platelet and leukocyte counts and biochemical profile (total serum protein and albumin dosages of sheep blood. The results demonstrate that charcoal in hemoperfuser cartridge: (1 decreases the serum in sheep blood volume, as consequence, (2 increases the serum proteins' concentration, and (iii exerts slight influence on albumin. The inclusion of tannic acid in hemoperfuser column precipitates some of serum proteins and albumin, decreasing their concentrations in the plasma serum. In conclusion, based on these effects we can suggest the use of 0.02 g tannic acid concentration and 8–20 mesh granulated charcoal in hemoperfuser cartridge for precipitating toxic proteins from snake venoms.

  7. Acid Precipitation: Causes and Consequences.

    Science.gov (United States)

    Babich, Harvey; And Others

    1980-01-01

    This article is the first of three articles in a series on the acid rain problem in recent years. Discussed are the causes of acid precipitation and its consequences for the abiotic and biotic components of the terrestrial and aquatic ecosystems, and for man-made materials. (Author/SA)

  8. Limnological aspects of acid precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Hendrey, G.R. (ed.)

    1978-01-01

    Lakes and streams in parts of Norway, Sweden, Canada, and the United States are being severely impacted by acidic precipitation. Scientists meeting at Sagamore, New York, agreed that this is the most serious limnological problem today. The factor responsible for determining the sensitivity of surface waters to acidification is alkalinity derived by weathering of soils and bedrock in the watershed. Acidification, defined as a reduction in alkalinity, can be quantified if preacidification alkalinity data exist, but often they do not. Data on pH and Ca from surface waters in areas not affected by acid precipitation were compared to similar data from areas which receive precipitation with a weighted average hydrogen ion concentration of pH < 4.6. A semiquantitative estimation of surface water acidification can be made for lakes and streams, where earlier chemistry data are lacking, based on this analysis of pH and Ca data. Biological responses to acidification range from a reduction in numbers of species of algae and zooplankton to complete elimination of all fish life. Major biological processes such as primary production and decomposition may be altered leading to an accumulation of plant material and organic debris within lakes and streams. Increased concentrations of aluminum from the ..mu..g/l to mg/l range have been found at levels shown to be toxic to fish. These elevated levels apparently result from the exchange of H/sup +/ and Al in the watershed. There also appears to be a relationship between lake acidification and the accumulation of mercury in fish. Problems of aluminum analysis received detailed attention, and watershed mass balances, comparative watershed studies, whole lake manipulations, synoptic surveys, and the liming of acidified waters were discussed. A priority-rated list of recommendations for research was presented.

  9. Acid Precipitation and the Forest Ecosystem

    Science.gov (United States)

    Dochinger, Leon S.; Seliga, Thomas A.

    1975-01-01

    The First International Symposium on Acid Precipitation and the Forest Ecosystem dealt with the potential magnitude of the global effects of acid precipitation on aquatic ecosystems, forest soils, and forest vegetation. The problem is discussed in the light of atmospheric chemistry, transport, and precipitation. (Author/BT)

  10. The weak acid nature of precipitation

    Science.gov (United States)

    John O. Frohliger; Robert L. Kane

    1976-01-01

    Recent measurements of the pH of precipitation leave no doubt that rainfall is acidic. Evidence will be presented that precipitation is a weak acid system. The results of this research indicate the need to establish standard sampling procedures to provide uniform sampling of precipitation

  11. A global assessment of precipitation chemistry and deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity and pH, and phosphorus

    Science.gov (United States)

    Vet, Robert; Artz, Richard S.; Carou, Silvina

    2014-08-01

    Investigating and assessing the chemical composition of precipitation and atmospheric deposition is essential to understanding how atmospheric pollutants contribute to contemporary environmental concerns including ecosystem acidification and eutrophication, loss of biodiversity, air pollution and global climate change. Evidence of the link between atmospheric deposition and these environmental issues is well established. The state of scientific understanding of this link is that present levels of atmospheric deposition of sulfur and nitrogen adversely affect terrestrial and aquatic ecosystems, putting forest sustainability and aquatic biodiversity at risk. Nitrogen and phosphorus loadings are linked to impacts on the diversity of terrestrial and aquatic vegetation through biological cycling, and atmospheric deposition plays a major role in the emission-transport-conversion-loss cycle of chemicals in the atmosphere as well as the formation of particulate matter and ozone in the troposphere. Evidence also shows that atmospheric constituents are changing the earth's climate through direct and indirect atmospheric processes. This Special Issue, comprising a single article titled "A global assessment of precipitation chemistry and deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity and pH, and phosphorus", presents a recent comprehensive review of precipitation chemistry and atmospheric deposition at global and regional scales. The information in the Special Issue, including all supporting data sets and maps, is anticipated to be of great value not only to the atmospheric deposition community but also to other science communities including those that study ecosystem impacts, human health effects, nutrient processing, climate change, global and hemispheric modeling and biogeochemical cycling. Understanding and quantifying pollutant loss from the atmosphere is, and will remain, an important component of each of these scientific fields as they

  12. Technical and economical assessment of formic acid to recycle phosphorus from pig slurry by a combined acidification-precipitation process.

    Science.gov (United States)

    Daumer, M-L; Picard, S; Saint-Cast, P; Dabert, P

    2010-08-15

    Dissolution by acidification followed by a liquid/solid separation and precipitation of phosphorus from the liquid phase is one possibility to recycle phosphorus from livestock effluents. To avoid increase of effluent salinity by using mineral acids in the recycling process, the efficiency of two organic acids, formic and acetic acid, in dissolving the mineral phosphorus from piggery wastewater was compared. The amount of formic acid needed to dissolve the phosphorus was reduced three fold, compared to acetic acid. The amount of magnesium oxide needed for further precipitation was decreased by two with formic acid. Neither the carbon load nor the effluent salinity was significantly increased by using formic acid. An economical comparison was performed for the chemical recycling process (mineral fertilizer) vs. centrifugation (organic fertilizer) considering the centrifugation and the mineral fertilizers sold in the market. After optimisation of the process, the product could be economically competitive with mineral fertilizer as superphosphate in less than 10 years. Copyright 2010 Elsevier B.V. All rights reserved.

  13. Contributions of acid rain research to the forest science-policy interface: learning from the national acid precipitation assessment program.

    Science.gov (United States)

    Charles E. Peterson; David S. Shriner

    2004-01-01

    During the 1970s, there was growing concern by scientists, policy officials and the general public in the USA over the possible effects of acid rain on human health and the environment (crops, forests, water, etc.). The lack of science-based information needed for policy and regulatory decisions led Congress to create an interagency task force in 1980 called the...

  14. Measurement of acid precipitation in Norway

    Science.gov (United States)

    Arne Semb

    1976-01-01

    Since January 1972, chemical analysis of daily precipitation samples from about 20 background stations in Norway has been carried out on a routine basis. Air monitoring is carried out at six stations. The chemical analysis programme is: sulphate, pH and acidity in precipitation, sulphates and sulphur dioxide in air. In addition, more detailed chemical analysis of...

  15. Geochemical and lithological factors in acid precipitation

    Science.gov (United States)

    James R. Kramer

    1976-01-01

    Acid precipitation is altered by interaction with rocks, sediment and soil. A calcareous region buffers even the most intense loading at pH ~8; an alumino silicate region with unconsolidated sediment buffers acid loadings at pH ~6.5; alumino silicate outcrops are generally acidified. Either FeOOH or alumino silicates are probable H+...

  16. Acid neutralization of precipitation in Northern China.

    Science.gov (United States)

    Wang, Yuesi; Yu, Wenpeng; Pan, Yuepeng; Wu, Dan

    2012-02-01

    There is an increasing concern over the impact of human-related emissions on the acid precipitation in China. However, few measurements have been conducted so far to clarify the acid-neutralization of precipitation on a regional scale. Under a network of 10 sites across Northern China operated during a 3-year period from December 2007 to November 2010, a total of 1118 rain and snow samples were collected. Of this total, 28% was acid precipitation with pH acid samples, 53% were found heavily acidic with pH value below 5.0, indicating significantly high levels of acidification of precipitation. Most of the acidity of precipitation was caused by H2SO4 and HNO3, their relative contribution being 72% and 28%, respectively. However; the contribution of HNO3 to precipitation acidity will be enhanced due to the increasing NO(x) and stable SO2 emissions in future. Neutralization factors for K+, NH4+, Ca2+, Na+, and Mg2+ were estimated as 0.06, 0.71, 0.72, 0.15, and 0.13, respectively. The application of multiple regression analysis further quantified higher NH4+ and Ca2+ contribution to the neutralization process, but the dominant neutralizing agent varied from site to site. The neutralization was less pronounced in the rural than urban areas, probably due to different levels of alkaline species, which strongly buffered the acidity. Presence of high concentrations of basic ions was mainly responsible for high pH of precipitation with annual volume-weighted mean (VWM) values larger than 5.6 at several sites. It was estimated that in the absence of buffering ions, for the given concentration of SO4(2-) and NO3-, the annual VWM pH of precipitation would have been recorded around 3.5 across Northern China. This feature suggested that emissions of particles and gaseous NH3 played very important role in controlling the spatial variations of pH of precipitation in the target areas.

  17. Experimental observations of boric acid precipitation scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Vaghetto, R., E-mail: r.vaghetto@tamu.edu; Childs, M., E-mail: masonchilds@tamu.edu; Jones, P., E-mail: pgjones87@tamu.edu; Lee, S., E-mail: sayalee@tamu.edu; Kee, E., E-mail: erniekee@gmail.com; Hassan, Y.A., E-mail: y-hassan@tamu.edu

    2017-02-15

    During a Loss of Coolant Accident (LOCA) in Light Water Reactors (LWR), borated water is injected into the core through the safety injection system. The continuous vaporization of the water from the core may increase the concentration of boric acid in the core that, under certain conditions may reach the solubility limit and precipitate. This includes scenarios where the liquid water supply to the core is affected by possible blockages due to debris accumulation. Questions have been raised on the effects of the precipitate in the core on the flow behavior, including the possibility of additional blockages produced by precipitate accumulation. A simple experimental facility was constructed to perform experimental observations of the behavior of borated water under the combined effects of the boiling and the boric acid precipitation (BAP). The facility consists of a transparent polycarbonate vertical pipe where forty-five heated rods have been installed to supply the power to the water to reach the saturation temperature, and maintain a desired boil-off rate. The layout and geometry of the experimental apparatus were conceived to emulate a simplified core of a Pressurized Water Reactor (PWR). Experimental observations have been conducted under two different conditions. Preliminary tests were conducted to observe the behavior of the water and the boric acid precipitate during a boil-off scenario without borated water addition (decreasing water level). During the main test runs, borated water was constantly injected from the top of the test section to maintain a constant mixture level in the test section. Both tests assumed no flow from the bottom of the test section which may be the case of PWR LOCA scenarios in presence of debris-generated core blockage. The observations performed with a set of cameras installed around the test section showed interesting effects of the vapor bubbles on the boric acid precipitate migration and accumulation in the test section. The

  18. Precipitation of humic acid with divalent ions

    DEFF Research Database (Denmark)

    Andersen, Niels Peder Raj; Mikkelsen, Lene Haugaard; Keiding, Kristian

    2001-01-01

    The aim of this study is to investigate precipitation proper-ties of humic acid (HA). This is done by studying a commercial available humic acid salt (HA) from which a phase diagram is established by adding various amounts of BaCl2 to different concentrations of HA at pH 5.5. The phase diagram...... shows tree characteristic regions with markedly different precipitation courses: region I at HA concentration below 0.15g/l, region H at HA concentration between 0.15 and similar to2g/l and rgeion IV at HA concentration above 3.5g/l. Furthermore, a forth intermediate region M is observed between similar...... to2 and 3.5g/l. In order to understand these measurements and precipitation behaviour a phase diagram model is constructed using a simple thermodynamic approach. The result of this analysis shows that precipitation in region I and U can be explained by a simple equilibrium reaction between the HA...

  19. The effect of acid precipitation on tree growth in eastern North America

    Science.gov (United States)

    Charles V. Cogbill

    1976-01-01

    Detailed study of the history of forest tree growth by tree-ring analysis is used to assess the effect of acid precipitation. The pattern and historical trends of acid precipitation deposition are compared with growth trends from mature forest stands in New Hampshire and Tennessee. No clear indication of a regional, synchronized decrease in tree growth was found. The...

  20. Effects of acidic deposition on the erosion of carbonate stone - experimental results from the U.S. National Acid Precipitation Assessment Program (NAPAP)

    Science.gov (United States)

    Baedecker, P.A.; Reddy, M.M.; Reimann, K.J.; Sciammarella, C.A.

    1992-01-01

    One of the goals of NAPAP-sponsored research on the effects of acidic deposition on carbonate stone has been to quantify the incremental effects of wet and dry deposition of hydrogen ion, sulfur dioxide and nitrogen oxides on stone erosion. Test briquettes and slabs of freshly quarried Indiana limestone and Vermont marble have been exposed to ambient environmental conditions in a long-term exposure program. Physical measurements of the recession of test stones exposed to ambient conditions at an angle of 30?? to horizontal at the five NAPAP materials exposure sites range from ~15 to ~30?? ??m yr-1 for marble, and from ~25 to ~45 ??m yr -1 for limestone, and are approximately double the recession estimates based on the observed calcium content of run-off solutions from test slabs. The difference between the physical and chemical recession measurements is attributed to the loss of mineral grains from the stone surfaces that are not measured in the run-off experiments. The erosion due to grain loss does not appear to be influenced by rainfall acidity, however, preliminary evidence suggests that grain loss may be influenced by dry deposition of sulfur dioxide between rainfall events. Chemical analyses of the run-off solutions and associated rainfall blanks suggest that ~30% of erosion by dissolution can be attributed to the wet deposition of hydrogen ion and the dry deposition of sulfur dioxide and nitric acid between rain events. The remaining ~70% of erosion by dissolution is accounted for by the solubility of carbonate stone in rain that is in equilibrium with atmospheric carbon dioxide ('clean rain'). These results are for marble and limestone slabs exposed at an angle of 30?? from horizontal. The relative contribution of sulfur dioxide to chemical erosion is significantly enhanced for stone slabs having an inclination of 60?? or 85??. The dry deposition of alkaline particulate material has a mitigating effect at the two urban field exposure sites at Washington, DC

  1. Skill assessment of precipitation nowcasting in Mediterranean Heavy Precipitation Events

    Science.gov (United States)

    Bech, Joan; Berenguer, Marc

    2013-04-01

    Very short-term precipitation forecasting (i.e nowcasting) systems may provide valuable support in the weather surveillance process as they allow to issue automated early warnings for heavy precipitation events (HPE) as reviewed recently by Pierce et al. (2012). The need for warnings is essential in densely populated regions of small catchments, such as those typically found in Mediterranean coastal areas, prone to flash-floods. Several HPEs that occurred in NE Spain are analyzed using a nowcasting system based on the extrapolation of rainfall fields observed with weather radar following a Lagrangian approach developed and tested successfully in previous studies (Berenguer et al. 2005, 2011). Radar-based nowcasts, with lead times up to 3 h, are verified here against quality-controlled weather radar quantitative precipitation estimates and also against a dense network of raingauges. The basic questions studied are the dependence of forecast quality with lead time and rainfall amounts in several high-impact HPEs such as the 7 September 2005 Llobregat Delta river tornado outbreak (Bech et al. 2007) or the 2 November 2008 supercell tornadic thunderstorms (Bech et al. 2011) - both cases had intense rainfall rates (30' amounts exceeding 38.2 and 12.3 mm respectively) and daily values above 100 mm. Verification scores indicated that forecasts of 30' precipitation amounts provided useful guidance for lead times up to 60' for moderate intensities (up to 1 mm in 30') and up to 2.5h for lower rates (above 0.1 mm). On the other hand correlations of radar estimates and forecasts exceeded Eulerian persistence of precipitation estimates for lead times of 1.5 h for moderate intensities (up to 0.8 mm/h). We complete the analysis with a discussion on the reliability of threshold to lead time dependence based on the event-to-event variability found. This work has been done in the framework of the ProFEWS project (CGL2010-15892). References Bech J, N Pineda, T Rigo, M Aran, J Amaro, M

  2. Potential impact of acid precipitation on arsenic and selenium.

    Science.gov (United States)

    Mushak, P

    1985-01-01

    The potential impact of acidic precipitation on the environmental mobility of the metalloids arsenic (As) and selenium (Se) has not been given much attention and is poorly understood. As with other elements, the interest here is the potential effect of environmental acidification on environmental behavior in ways that are relevant to human exposure to these metalloids. Available information on acid precipitation and the environmental behavior of these metalloids do, however, permit some preliminary conclusions to be drawn. Both As and Se appear to be mobilized from household plumbing into tap water by the corrosive action of soft, mildly acidic water, while surface water catchment systems in areas impacted by acidic deposition may contain elevated soluble As levels. Acidification of aquatic ecosystems that are drinking water sources may pose the prospect of enhanced release of As from sediment to water as well as reduction in water levels of Se. Acidification of ground waters, where As appears to be especially mobile, is of particular concern in this regard. The potential impact of acidic deposition on As and Se in soils cannot readily be assessed with respect to human exposure, but it would appear that the behavior of these metalloids in poorly buffered, poorly immobilizing soils, e.g., sandy soils of low metal hydrous oxide content, would be most affected. The effect is opposite for the two elements; lowered pH would appear to enhance As mobility and to reduce Se availability. Altered acidity of both soil and aquatic systems poses a risk for altered biotransformation processes involving both As and Se, thereby affecting the relative amounts of different chemical forms varying in their toxicity to humans as well as influencing biogeochemical cycling. PMID:4076075

  3. Changes in chemical processes in soils caused by acid precipitation

    Science.gov (United States)

    Stephen A. Norton

    1976-01-01

    The acidification of precipitation is an accomplished fact. The only question that remains is whether the present trend of acidification is to continue into the future, and if so, to what degree. A related question is, are the consequences of acid precipitation reversible and to what extent, or over what time period? Research conducted over the last twenty years has...

  4. Acid Precipitation Awareness Curriculum Materials in the Life Sciences.

    Science.gov (United States)

    Stubbs, Harriett S.

    1983-01-01

    Provides an outline of course content for acid precipitation and two acid rain activities (introduction to pH and effects of acid rain on an organism). Information for obtaining 20 additional activities as well as an information packet containing booklets, pamphlets, and articles are also provided. (JN)

  5. Acid Precipitation in the Pacific Northwest.

    Science.gov (United States)

    Baldwin, John; Kozak, David

    1988-01-01

    Discusses the causes, sources, and problems associated with acid deposition in the Pacific Northwest. Includes a learning activity about acid rain, "Deadly Skies," which was adapted from the Project WILD Aquatic Supplement. (TW)

  6. Acid Precipitation: Scientific Progress and Public Awareness.

    Science.gov (United States)

    Cowling, Ellis B.

    1983-01-01

    Describes certain perspectives on scientific research and on the public debates about acid deposition and its effects. Although primary attention is given to European/North American research, the ideas developed are relevant in any world region sensitive to acid deposition resulting from intense industrialization. (Author/JN)

  7. Chemical composition of acid precipitation in central Texas

    Science.gov (United States)

    Hal B. H., Jr. Cooper; Jerry M. Demo; Jose A. Lopez

    1976-01-01

    Studies were undertaken to determine factors affecting composition of acidic precipitation formation in the Austin area of Central Texas. The study was initiated to determine background levels of acid and alkalinity producing constituents in an area with elevated natural dust levels from nearby limestone rock formations. Results showed normal rainfall pH values of 6.5...

  8. Acidic precipitation: considerations for an air-quality standard

    Energy Technology Data Exchange (ETDEWEB)

    Evans, L.S.; Hendrey, G.R.; Stensland, G.J.; Johnson, D.W.; Francis, A.J.

    1980-01-01

    Acidic precipitation, wet or frozen deposition with a hydrogen ion concentration greatern than 2.5 ..mu..eq l/sup -1/ is a significant air pollution problem in the United States. The chief anions accounting for the hydrogen ions in rainfall are nitrate and sulfate. Agricultural systems are more likely to derive net nutritional benefits from increasing inputs of acidic rain than are forest systems when soils alone are considered. Agricultural soils may benefit because of the high N and S requirements of agricultural plants. Detrimental effects to forest soils may result if atmospheric H/sup +/ inputs significantly add to or exceed H/sup +/ production by soils. Acidification of fresh waters of southern Scandinavia, southwestern Scotland, southeastern Canada, and northeastern United States is caused by acid deposition. Areas of these regions in which this acidification occurs have in common, highly acidic precipitation with volume weighted mean annual H/sup +/ concentrations of 25 ..mu..eq l/sup -1/ or higher and slow weathering granitic or precambrian bedrock with thin soils deficient in minerals which would provide buffer capacity. Biological effects of acidification of fresh waters are detectable below pH 6.0. As lake and stream pH levels decrease below pH. 6.0, many species of plants, invertebrates, and vertebrates are progressively eliminated. Generally, fisheries are impacted below pH 5.0 and are completely destroyed below pH 4.8. There are few studies that document effects of acidic precipitation on terrestrial vegetation to establish an air quality standard. It must be demonstrated that current levels of precipitation acidity alone significantly injure terrestrial vegetation. In terms of documented damanges, current research indicates that establishing a standard for precipitation for the volume weighted annual H/sup +/ concentration at 25 ..mu..eq l/sup -1/ may protect the most sensitive areas from permanent lake acidification.

  9. Glycation inhibits trichloroacetic acid (TCA)-induced whey protein precipitation

    Science.gov (United States)

    Four different WPI saccharide conjugates were successfully prepared to test whether glycation could inhibit WPI precipitation induced by trichloroacetic acid (TCA). Conjugates molecular weights after glycation were analyzed with SDS-PAGE. No significant secondary structure change due to glycation wa...

  10. Teacher's Resource Guide on Acidic Precipitation with Laboratory Activities.

    Science.gov (United States)

    Barrow, Lloyd H.

    The purpose of this teacher's resource guide is to help science teachers incorporate the topic of acidic precipitation into their curricula. A survey of recent junior high school science textbooks found a maximum of one paragraph devoted to the subject; in addition, none of these books had any related laboratory activities. It was on the basis of…

  11. Hydrogen ion speciation in the acid precipitation of the northeastern United States

    Science.gov (United States)

    James N. Galloway; Gene E. Likens; Eric S. Edgerton

    1976-01-01

    The acidity of precipitation in rural, forested areas of the northeastern United States is dominated by the strong mineral acids, sulfuric and nitric. Weak acids have a negligible effect on the measured acidity (pH) of precipitation. These conclusions are based on total acidity titrations and detailed analysis of organic and inorganic components in precipitation.

  12. Precipitation variability assessment of northeast China: Songhua ...

    Indian Academy of Sciences (India)

    Variability in precipitation is critical for the management of water resources. In this study, the research entropy base concept was applied to investigate spatial and temporal variability of the precipitation during 1964–2013 in the Songhua River basin of Heilongjiang Province in China. Sample entropy was applied on ...

  13. Precipitation variability assessment of northeast China: Songhua ...

    Indian Academy of Sciences (India)

    Variability in precipitation is critical for the management of water resources. In this study, the researchentropy base concept was applied to investigate spatial and temporal variability of the precipitationduring 1964–2013 in the Songhua River basin of Heilongjiang Province in China. Sample entropy wasapplied on ...

  14. Proceedings of the first international symposium on acid precipitation and the forest ecosystem

    Science.gov (United States)

    L.S. Dochinger; T.A. Seliga

    1976-01-01

    These Proceedings report on the results of The First International Symposium on Acid Precipitation and the Forest Ecosystem which was held at The Ohio State University, Columbus, Ohio, U.S.A., on May 12-15, 1975. The Symposium focused on four related topics: (1) atmospheric chemistry, transport and precipitation; and effects of acidic precipitation on (2) aquatic...

  15. 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.

  16. Influence of commercial (Fluka) naphthenic acids on acid volatile sulfide (AVS) production and divalent metal precipitation.

    Science.gov (United States)

    McQueen, Andrew D; Kinley, Ciera M; Rodgers, John H; Friesen, Vanessa; Bergsveinson, Jordyn; Haakensen, Monique C

    2016-12-01

    Energy-derived waters containing naphthenic acids (NAs) are complex mixtures often comprising a suite of potentially problematic constituents (e.g. organics, metals, and metalloids) that need treatment prior to beneficial use, including release to receiving aquatic systems. It has previously been suggested that NAs can have biostatic or biocidal properties that could inhibit microbially driven processes (e.g. dissimilatory sulfate reduction) used to transfer or transform metals in passive treatment systems (i.e. constructed wetlands). The overall objective of this study was to measure the effects of a commercially available (Fluka) NA on sulfate-reducing bacteria (SRB), production of sulfides (as acid-volatile sulfides [AVS]), and precipitation of divalent metals (i.e. Cu, Ni, Zn). These endpoints were assessed following 21-d aqueous exposures of NAs using bench-scale reactors. After 21-days, AVS molar concentrations were not statistically different (pprecipitation were not vulnerable to NAs, indicating passive treatment systems utilizing sulfide production (AVS) could be used to treat metals occurring in NAs affected waters. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Crosslinkers of Different Types in Precipitation Polymerization of Acrylic Acid

    Directory of Open Access Journals (Sweden)

    H. Eshaghi

    2013-01-01

    Full Text Available Crosslinked poly(acrylic acids were prepared using two types of crosslinker by precipitation polymerization method in a binary organic solvent. N,N’-methylenebisacrylamide (MBA and polyethylene glycol dimethacrylate (PEGDMA-330 were used as low-molecular weight and long-chain crosslinkers, respectively. The effect of various types of crosslinkers on polymer characteristics (i.e., gel content, equilibrium swelling, glass transition temperature, and rheological properties was investigated. Maximum amount of viscosity was obtained by using long-chain crosslinker. The Flory-Rehner equation and rubber elasticity theory were used to discuss the network structure of polymer. It was observed that, the glass transition temperature (Tg of the synthesized polymer containing PEGDMA-330 is higher than that of polymer containing MBA. Apparent and rotational viscosity were used to determine the optimal crosslinker type. In addition, the consistencycoefficient (m and flow behavior index (n parameter of Ostwald equation were investigated as well.

  18. Acidity in Precipitation and Solar North-South Asymmetry

    Directory of Open Access Journals (Sweden)

    Ga-Hee Moon

    2014-12-01

    Full Text Available We are motivated by both the accumulating evidence for the connection of solar variability to the chemistry of nitrogen oxide in the atmosphere and recent finding that the Galactic cosmic-ray (GCR influx is associated with the solar northsouth asymmetry. We have analyzed the measured pH in precipitation over the 109 stations distributed in the United States. We have found that data of pH in precipitation as a whole appear to be marginally anti-correlated with the solar asymmetry. That is, rain seems to become less acidic when the southern hemisphere of the Sun is more active. The acidity of rain is also found to be correlated with the atmospheric temperature, while not to be correlated with solar activity itself. We have carried on the analysis with two subsamples in which stations located in the east and in the west. We find that the pH data derived from the eastern stations which are possibly polluted by sulfur oxides and nitrogen oxides are not correlated with the solar asymmetry, but with the temperature. On the contrary, the pH data obtained from the western stations are found to be marginally anti-correlated with the solar asymmetry. In addition, the pH data obtained from the western stations are found to be correlated with the solar UV radiation. We conclude by briefly pointing out that a role of the solar asymmetry in the process of acidification of rain is to be further examined particularly when the level of pollution by sulfur oxides and nitrogen oxides is low.

  19. A Qualitative Assessment of Factors Precipitating Intergroup ...

    African Journals Online (AJOL)

    The environmental and social political context of a university may have direct import on factors that can create conflict situations among the various groups that make up the university; academic, non academic and university administration. Consequently this paper takes a critical assessment of six universities (private, state ...

  20. Impact of acid precipitation on freshwater ecosystems on Norway

    Science.gov (United States)

    Richard F. Wright; Torstein Dale; Egil T. Gjessing; George R. Hendrey; Arne Henriksen; Merete Johannessen; Ivar P. Muniz

    1976-01-01

    Extensive studies of precipitation chemistry during the last 20 years have clearly shown that highly polluted precipitation falls over large areas of Scandinavia, and that this pollution is increasing in severity and geographical extent. Precipitation in southern Norway, Sweden, and Finland contains large amounts of H+, SO4...

  1. The effect of precipitation collector design on the measured acid content of precipitation

    Science.gov (United States)

    H. A. Weibe

    1976-01-01

    In order to evaluate the effect of different types of collectors on the measured chemical constituents of monthly precipitation collections, an array of fourteen precipitation samplers of five different designs has been in operation at Woodbridge, Ontario since March 1974. The collectors are located in an open field near the city of Toronto in an area of approximately...

  2. Effects of precipitation on soil acid phosphatase activity in three successional forests in Southern China

    OpenAIRE

    Huang, W; Liu, J.; Zhou, G.; Zhang, D; Deng, Q

    2011-01-01

    Phosphorus (P) is often a limiting nutrient for plant growth in tropical and subtropical forests. Global climate change has led to alterations in precipitation in the recent years, which inevitably influences P cycling. Soil acid phosphatase plays a vital role in controlling P mineralization, and its activity reflects the capacity of P supply to ecosystems. In order to study the effects of precipitation on soil acid phosphatase activity, an experiment of precipitation treatments (no pr...

  3. Long range transport of air pollutants in Europe and acid precipitation in Norway

    Science.gov (United States)

    Jack Nordo

    1976-01-01

    Observations show that pollutants from large emission sources may cause significant air concentrations 500 to 1000 miles away. Very acid precipitation occurs in such periods. The scavenging is often intensified by the topography. Case studies will be presented, with special emphasis on acid precipitation in Scandinavia. Large scale dispersion models have been developed...

  4. The influences on leachate from landfill of incineration residuals by acid precipitation.

    Science.gov (United States)

    Chow, Jing-Dong; Chai, Wan-Lan

    2007-04-02

    Incineration of municipal solid wastes (MSW) is the main method of waste management in Taiwan. Although the incineration of MSW processes the solid wastes at 850-950 degrees C and destroys most of the organics, the content of incineration ashes is still a problem for landfill. Moreover, acid precipitation is much worse than before in Taiwan, especially in the northern areas. For instance, the occurrence probabilities of acid precipitation measured from 1991 to 1998 in Taipei increase from 73% to 85%. Therefore, it is more important to get a series of data that will help explore the influence of acid precipitation during disposal on characterization of pollutants than to analyze the ash properties after the incinerators have been constructed and regularly used. In this investigation, the disposal site of incineration ashes is simulated in laboratory by test columns. An irrigation experiment is taken to simulate the acid precipitation at room temperature. In order to explore the exact influence on leachate quality of the main chemical composition of acid precipitation, columns are migrated with different concentrations of sulfate in acid precipitation. This investigation showed that the sulfate concentration of acid precipitation has an increasing effect on the accumulative release of heavy metals, such as Zn, Pb and Cu, from leachate. The sulfate concentration of acid precipitation, however, will not influence the trend of chemical oxygen demand (COD), biochemical oxygen demand (BOD(5)) and total organic carbon (TOC) in the leachate release.

  5. Seasonal patterns in acidity of precipitation and their implications for forest stream ecosystems

    Science.gov (United States)

    James W. Hornbeck; Gene E. Likens; John S. Eaton

    1976-01-01

    Data collected since 1965 at a network of 9 stations in the northeastern United States show that precipitation is most acid in the growing season (May-September) and least acid in winter (December-February). For the Hubbard Brook station in New Hampshire, where the mean hydrogen ion content of precipitation ranges between 46 μeq/l in winter and 102 μ...

  6. The effect of scale in daily precipitation hazard assessment

    Directory of Open Access Journals (Sweden)

    J. J. Egozcue

    2006-01-01

    Full Text Available Daily precipitation is recorded as the total amount of water collected by a rain-gauge in 24 h. Events are modelled as a Poisson process and the 24 h precipitation by a Generalised Pareto Distribution (GPD of excesses. Hazard assessment is complete when estimates of the Poisson rate and the distribution parameters, together with a measure of their uncertainty, are obtained. The shape parameter of the GPD determines the support of the variable: Weibull domain of attraction (DA corresponds to finite support variables as should be for natural phenomena. However, Fréchet DA has been reported for daily precipitation, which implies an infinite support and a heavy-tailed distribution. Bayesian techniques are used to estimate the parameters. The approach is illustrated with precipitation data from the Eastern coast of the Iberian Peninsula affected by severe convective precipitation. The estimated GPD is mainly in the Fréchet DA, something incompatible with the common sense assumption of that precipitation is a bounded phenomenon. The bounded character of precipitation is then taken as a priori hypothesis. Consistency of this hypothesis with the data is checked in two cases: using the raw-data (in mm and using log-transformed data. As expected, a Bayesian model checking clearly rejects the model in the raw-data case. However, log-transformed data seem to be consistent with the model. This fact may be due to the adequacy of the log-scale to represent positive measurements for which differences are better relative than absolute.

  7. Caprylic acid precipitation method for impurity reduction: an alternative to conventional chromatography for monoclonal antibody purification.

    Science.gov (United States)

    Brodsky, Yan; Zhang, Cheng; Yigzaw, Yinges; Vedantham, Ganesh

    2012-10-01

    We report the use of caprylic acid based impurity precipitation as (1) an alternative method to polishing chromatography techniques commonly used for monoclonal antibody purification and (2) an impurity reduction step prior to harvesting the bioreactor. This impurity reduction method was tested with protein A purified antibodies and with cell culture fluid. First, the operational parameters influencing precipitation of host cell proteins and high molecular weight aggregate in protein A pools were investigated. When used as a polishing step, the primary factor affecting purification and yield was determined to be pH. Caprylic acid precipitation was comparable to polishing IEX chromatography in reducing host cell protein and aggregate levels. A virus reduction study showed complete clearance of a model retrovirus during caprylic acid precipitation of protein A purified antibody. Caprylic acid mediated impurity precipitation in cell culture showed that the impurity clearance was generally insensitive to pH and caprylic acid concentration whereas yield was a function of caprylic acid concentration. Protein A purification of caprylic acid precipitated cell culture fluid generated less turbid product pool with reduced levels of host cell proteins and high molecular weight aggregate. The results of this study show caprylic acid precipitation to be an effective purification method that can be incorporated into a production facility with minimal cost as it utilizes existing tanks and process flow. Eliminating flow through chromatography polishing step can provide process intensification by avoiding the process tank volume constraints for high titer processes. Copyright © 2012 Wiley Periodicals, Inc.

  8. Protein-poly(amino acid) complex precipitation for high-concentration protein formulation.

    Science.gov (United States)

    Kurinomaru, Takaaki; Maruyama, Takuya; Izaki, Shunsuke; Handa, Kenji; Kimoto, Tomoaki; Shiraki, Kentaro

    2014-08-01

    A method for concentration of protein solutions is required for high-dosage protein formulation. Here, we present a precipitation-redissolution method by poly(amino acid) for proteins, including therapeutic enzymes, antibodies, and hormones. The proteins were fully precipitated by the addition of poly-L-lysine or poly-L-glutamic acid at low ionic strength, after which precipitate was dissolved at physiological ionic strength. The activities and secondary structures of redissolved proteins, especially antibodies, were almost identical to the native state. The precipitation-redissolution method is a simple and rapid technique for concentration of protein formulations. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  9. Application of trichloroacetic acid-acetone precipitation method for protein extraction in bone tissue.

    Science.gov (United States)

    Yong-feng, Cui; Zhen, Yang; Bao-hua, Zhu; Lu-wei, Xiao; Pei-jian, Tong

    2011-04-01

    To explore the feasibility and efficiency of extracting protein from bone tissue using trichloroacetic acid (TCA)-acetone precipitation method. Hydrochloric acid (HCL) decalcification method and TCA-acetone precipitation method were separately used for bone protein extraction. The efficiencies of these two methods were compared. TCA-acetone precipitation method had significantly higher extraction efficiency. Compared with HCL decalcification method, it had less pollution from bone marrow hematopoietic tissue. Protein band distribution was similar between these two methods. TCA-acetone precipitation method is useful for bone proteomics research.

  10. The history and character of acid precipitation in eastern North America

    Science.gov (United States)

    Charles V. Cogbill

    1976-01-01

    The history and present distribution of precipitation acidity in eastern North America is reviewed. Precipitation chemistry from the 1920's indicates heavy ionic deposition, but low acidity (calculated) in Tennessee (pH 7.4) and New York (pH 6.15). However, high acidity was apparently widespread over northeast North America by 1955-56 and measured pH's below...

  11. Effects of precipitation on soil acid phosphatase activity in three successional forests in southern China

    Science.gov (United States)

    Huang, W.; Liu, J.; Zhou, G.; Zhang, D.; Deng, Q.

    2011-07-01

    Phosphorus (P) is often a limiting nutrient for plant growth in tropical and subtropical forests. Global climate change has led to alterations in precipitation in the recent years, which inevitably influences P cycling. Soil acid phosphatase plays a vital role in controlling P mineralization, and its activity reflects the capacity of organic P mineralization potential in soils. In order to study the effects of precipitation on soil acid phosphatase activity, an experiment with precipitation treatments (no precipitation, natural precipitation and doubled precipitation) in three successional forests in southern China was carried out. The three forests include Masson pine forest (MPF), coniferous and broad-leaved mixed forest (MF) and monsoon evergreen broad-leaved forest (MEBF). Results showed that driven by seasonality of precipitation, changes in soil acid phosphatase activities coincided with the seasonal climate pattern, with significantly higher values in the wet season than in the dry season. Soil acid phosphatase activities were closely linked to forest successional stages, with enhanced values in the later stages of forest succession. In the dry season, soil acid phosphatase activities in the three forests showed a rising trend with increasing precipitation treatments. In the wet season, soil acid phosphatase activity was depressed by no precipitation treatment in the three forests. However, doubled precipitation treatment exerted a significantly negative effect on it only in MEBF. These results indicate that the potential transformation rate of organic P might be more dependent on water in the dry season than in the wet season. A decrease in organic P turnover would occur in the three forests if there was a drought in a whole year in the future. More rainfall in the wet season would also be adverse to organic P turnover in MEBF due to its high soil moisture.

  12. PRECIPITATION REACTION OF CLAVULANIC ACID: THERMODYNAMIC AND ELECTRONIC STUDY

    Directory of Open Access Journals (Sweden)

    Ana C. Granato

    Full Text Available In the present article the theoretical calculation of thermodynamic parameters for the two main precipitation agents, potassium 2-ethylhexanoate and t-octylamine, employed by the pharmaceutical industry to obtain potassium clavulanate for clinical use, is described. The results obtained using the standard thermochemistry calculation in the Gaussian package and by calculation of the reactivity indexes of the reagents and products are compared. The calculated thermodynamic parameters indicate that the reactivity indexes present a better correlation with the experimentally obtained percentage yield. In addition, a series of additional precipitation agents that are also used in industrial procedures to obtain potassium clavulanate for clinical use, were compared. This was done to verify if any present, a priori, better properties than potassium 2-ethylhexanoate or t-octylamine. The consistency of the reactivity indexes calculated clearly suggests that the methodology employed can be used to screen future precipitation agents for possible use in the production of potassium clavulanate.

  13. Acid-Base and Precipitation Equilibria in Wine

    Science.gov (United States)

    Palma, Miguel; Barroso, Carmelo G.

    2004-01-01

    Experiments are performed to establish the changes of pH during the precipitation of potassium hydrogen tartrate, with its unfavorable impact on the stability of wine. Students, thus, obtain a clearer understanding of the interplay between a variety of chemical equilibria within a single medium.

  14. Acidic precipitation at a site within the northeastern conurbation

    Science.gov (United States)

    Jay S. Jacobson; Laurence I. Heller; Paul Van Leuken

    1976-01-01

    Rain and snow were collected in plastic beakers either manually or with a Wong sampler during 58 precipitation events in 1974 at Yonkers, New York approximately 24 km north of the center of New York City. Determinations were made of total dissolved ionic species, free hydrogen ions, total hydrogen ions, sulfate, nitrate, chloride, and fluoride. Conductivity...

  15. Acidic leaching and precipitation of zinc and manganese from spent battery powders using various reductants.

    Science.gov (United States)

    Sayilgan, E; Kukrer, T; Yigit, N O; Civelekoglu, G; Kitis, M

    2010-01-15

    The main objective of this study was to investigate the effects of reductive acidic leaching and further precipitation on the recovery of manganese and zinc from spent alkaline and zinc-carbon battery powders. Ascorbic acid (AA), citric acid (CA) and oxalic acid (OA) were tested as the reductants. Sodium hydroxide and potassium hydroxide were used as precipitating agents. OA with H(2)SO(4) or HCl was not effective on the leaching of zinc due to the formation of zinc oxalate precipitates. However, the other reducing agents (CA and AA) tested under various experimental conditions were effective in the acidic leaching of both zinc and manganese. Leaching yields of both manganese and zinc were higher at leach temperature of 90 degrees C than those at 30 degrees C. Leach solutions were purified by the selective precipitation of manganese and zinc using KOH or NaOH. Complete precipitation was obtained for Mn at pH 9-10 and for Zn at pH 7-8. The use of ascorbic acid or citric acid as reductants in acidic leaching appears to be effective in the simultaneous leaching and further recovery of zinc and manganese from spent alkaline and zinc-carbon battery powders.

  16. The Debate over Acid Precipitation--Opposing Views--Status of Research.

    Science.gov (United States)

    1981-09-11

    carbon dioxide from the atmosphere, so precipitation is usually called acidic only if it has a pH oelow 5.6. Rain with pH=4.6 has ten times as much...about pH 4.0. For comparison, the theoretical value for precipitation from a "normal" atmosphere containing carbon dioxide as its only acid would be about...acid as normal, wnile rain at pH=4.u is forty times as acidic as normal. For comparison, vinegar has a pH about 3.0. 2 - ,-. APPENDIX I APPENDIX I

  17. Comparative Assessment of Statistical Downscaling Methods for Precipitation in Florida

    Science.gov (United States)

    Goly, A.; Teegavarapu, R. S.

    2012-12-01

    Several statistical downscaling models have been developed in the past couple of decades to assess the hydrologic impacts of climate change by projecting the station-scale hydrological variables from large-scale atmospheric variables simulated by General Circulation Models (GCMs). GCMs in general are capable in capturing the large-scale circulation patterns and correctly model smoothly varying fields such as surface pressure, but it is extremely unlikely that these models properly reproduce non-smooth fields such as precipitation. This paper presents and compares different statistical downscaling methods involving Multiple Linear Regression (MLR), Positive Coefficient Regression (PCR), Stepwise Regression (SWR) and Support Vector Machine (SVM) for estimation of rainfall in the state of Florida, USA, which is considered to be a climatically sensitive region. The explanatory variables/predictors used in the current study are mean sea-level pressure, air temperature, geo-potential height, specific humidity, U-wind and V-wind. Principal Component Analysis (PCA) and Fuzzy C-Means (FCM) clustering techniques are used to reduce the dimensionality of the dataset and identify the circulation patterns on precipitation in different clusters. Downscaled precipitation data obtained from widely used Bias-Correction Spatial Disaggregation (BCSD) downscaling technique is compared along with the other downscaling methods. The performance of the models is evaluated using various performance measures and it was found that the SVM model performed better than all the other models in reproducing most monthly rainfall statistics at 18 locations. Output from the third generation Canadian Global Climate Model (CGCM3) GCM for A1B scenario was used for future precipitation projection. For the projection period 2001-2010, MLR was used and evaluated as a substitute to the traditional spatial interpolation linking the variables at the GCM grid to NCEP grid scale. It has been found that the

  18. Impacts of acid precipitation on coniferous forest ecosystems

    Science.gov (United States)

    Gunnar Abrahamsen; Richard Horntvedt; Bjorn Tveite

    1976-01-01

    This paper summarizes the results from current studies in Norway. One main approach is the application of artificial acid "rain" and of lime to field plots and lysimeters. Application during two growth seasons of 50 mm per month of "rain water" of pH 3 to a podzol soil increased the acidity of the humus and decreased the base saturation. The...

  19. Comparison of Four Strong Acids on the Precipitation Potential of Gypsum in Brines During Distillation of Pretreated, Augmented Urine

    Science.gov (United States)

    Muirhead, Dean; Carrier, Christopher

    2012-01-01

    In this study, three different mineral acids were substituted for sulfuric acid (H2SO4) in the urine stabilizer solution to eliminate the excess of sulfate ions in pretreated urine and assess the impact on maximum water recovery to avoid precipitation of minerals during distillation. The study evaluated replacing 98% sulfuric acid with 85% phosphoric acid (H3PO4), 37% hydrochloric acid (HCl), or 70% nitric acid (HNO3). The effect of lowering the oxidizer concentration in the pretreatment formulation also was studied. This paper summarizes the test results, defines candidate formulations for further study, and specifies the injection masses required to stabilize urine and minimize the risk of mineral precipitation during distillation. In the first test with a brine ersatz acidified with different acids, the solubility of calcium in gypsum saturated solutions was measured. The solubility of gypsum was doubled in the brines acidified with the alternative acids compared to sulfuric acid. In a second series of tests, the alternative acid pretreatment concentrations were effective at preventing precipitation of gypsum and other minerals up to 85% water recovery from 95th-percentile pretreated, augmented urine. Based on test results, phosphoric acid is recommended as the safest alternative to sulfuric acid. It also is recommended that the injected mass concentration of chromium trioxide solution be reduced by 75% to minimize liquid resupply mass by about 50%, reduce toxicity of brines, and reduce the concentration of organic acids in distillate. The new stabilizer solution formulations and required doses to stabilize urine and prevent precipitation of minerals up to 85% water recovery are given. The formulations in this study were tested on a limited number of artificially augmented urine batches collected from employees at the Johnson Space Center (JSC). This study successfully demonstrated that the desired physical and chemical stability of pretreated urine and brines

  20. [Concentrations and acidity contributions of acetate and formate in precipitation at 14 stations of China].

    Science.gov (United States)

    He, Xiao-huan; Xu, Xiao-bin; Yu, Xiao-lan; Tang, Jie

    2010-04-01

    To investigate the concentrations of organic acids in precipitation in China and their contributions to the total acidity of precipitation, samples were taken at 14 stations of regional representativeness in 2007 and analyzed for acetate and formate using ion chromatography. In this paper, data of acetate and formate in precipitation at 14 stations are presented, wet depositions of these organic acids are calculated, and contributions of them to the total free acidity (TFA) of precipitation are estimated. Based on the measurements, the mean concentrations of formate at different stations were in the range of 0.96-3.43 micromol/L, and those of acetate in the range of 0-5.13 micromol/L, close to the levels at remote sites in other countries and at the lower ends of concentration ranges from previous measurements in China. Comparisons indicate that the concentrations of the organic acids at remote sites are lower than those at sites in the vicinity of urban areas. The annual wet depositions of formate and acetate were estimated to be in the ranges of 0.38-4.18 mmol/(m2 x a) and 0.06-5.87 mmol/(m2 x a), respectively, with larger depositions in southern China and smaller depositions in northern China. The relative contributions of the two organic acids to the TFA of precipitation were estimated to be in the range of 0.02%-51.6%, with an overall average of 2.95%. This suggests that although acid rain in China is mainly caused by emissions of sulfur and nitrogen oxides, organic acids can significantly contribute to the acidification of precipitation in some regions and during some periods, hence need to be included in observational studies of acid rain.

  1. Considerations of an air-quality standard to protect terrestrial vegetation from acidic precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Evans, L.S.

    1981-01-01

    Studies on the effects of acidic precipitation which is here defined as wet or frozen deposition with a hydrogen ion concentration greater than 2.5 ..mu..eq 1/sup -1/, are reviewed. At the present time there is an inadequate amount of information that shows decreases in crop growth except for one field study. Most studies with plants (crops and forests) are inadequate for standard setting because they are not conducted in the field with adequate randomization of plots coupled with rigorous statistical analyses. Although visible injury to foliage has been documented in a variety of greenhouse studies, no experimental evidence demonstrates loss of field crop value or reduction in plant productivity due to visible foliar injury. Acidic precipitation can contribute nutrients to vegetation and could also influence leaching rates of nutrients from vegetation. Although these processes occur, there are no data that show changes in nutrient levels in foliage that relate to crop or natural ecosystem productivity. Experimental results show that fertilization of ferns is inhibited by current levels of acidic precipitation in the northeastern United States. However, the overall impacts of inhibited fertilization on perpetuation of the species or ecosystem productivity have not been evaluated. Simulated acidic precipitation has been shown to effect plant pathogens in greenhouse and field experiments. Simulated acidic precipitation inhibited pathogen activities under some circumstances and promoted pathogen activities under other circumstances. No conclusion can be drawn about the effects of current levels of precipitation acidity on plant pathogen-host interactions. From these data it must be concluded that research on the effects of acidic precipitation on terrestrial vegetation is too meager to draw any conclusions with regard to an air quality standard.

  2. Plasmodium falciparum-Derived Uric Acid Precipitates Induce Maturation of Dendritic Cells

    Science.gov (United States)

    van de Hoef, Diana L.; Coppens, Isabelle; Holowka, Thomas; Ben Mamoun, Choukri; Branch, OraLee; Rodriguez, Ana

    2013-01-01

    Malaria is characterized by cyclical fevers and high levels of inflammation, and while an early inflammatory response contributes to parasite clearance, excessive and persistent inflammation can lead to severe forms of the disease. Here, we show that Plasmodium falciparum-infected erythrocytes contain uric acid precipitates in the cytoplasm of the parasitophorous vacuole, which are released when erythrocytes rupture. Uric acid precipitates are highly inflammatory molecules that are considered a danger signal for innate immunity and are the causative agent in gout. We determined that P. falciparum-derived uric acid precipitates induce maturation of human dendritic cells, increasing the expression of cell surface co-stimulatory molecules such as CD80 and CD86, while decreasing human leukocyte antigen-DR expression. In accordance with this, uric acid accounts for a significant proportion of the total stimulatory activity induced by parasite-infected erythrocytes. Moreover, the identification of uric acid precipitates in P. falciparum- and P. vivax-infected erythrocytes obtained directly from malaria patients underscores the in vivo and clinical relevance of our findings. Altogether, our data implicate uric acid precipitates as a potentially important contributor to the innate immune response to Plasmodium infection and may provide a novel target for adjunct therapies. PMID:23405174

  3. Effects of acidic precipitation on host-parasite interactions

    Energy Technology Data Exchange (ETDEWEB)

    Shriner, D.S.

    1974-01-01

    During the past decade, the average acidity of rain and snow increased by 1-2 pH units in many parts of Europe and North America. Little is known of the effects of acid rain resulting from dissolution of sulfur dioxide on biological systems. The effects of simulated sulfuric acid rain on four host-pathogen system were studied. Plants were exposed in greenhouse and field to simulated rain of pH 3.2 or pH 6.0 in amounts and intervals common to weather patterns of the eastern United States. Simulated acid rain resulted in: (1) an 86% inhibition in telia production of Cronartium fusiforme on willow oak (Quercus phellos); (2) a 66% inhibition in the production of root-knot nematodes (Meloidogyne hapla) on field grown kidney beans (Phaseolus vulgaris Red Kidney); (3) a 20% decrease in the severity of Uromyces phaseoli infection of field grown kidney beans; and (4) either stimulated or inhibited development of halo blight on kidney bean (caused by Pseudomonas phaseolicola) depending upon the segment of the disease cycle in which the stress occurred: (a) simulated acid rain before inoculation stimulated disease development; (b) suspension of inoculum in acid rain decreased inoculum potential; and (c) acid rain after infection inhibited disease development. Results suggest that the pH of rain is a new environmental parameter of concern to plant pathologists.

  4. Acid Precipitation Learning Materials: Science, Environmental and Social Studies, Grades 6-12.

    Science.gov (United States)

    Hessler, Edward W.

    The major environmental problem of acid precipition is addressed through a series of activities contained in this guide for teachers of grades 6 through 12. Exercises are provided to help students learn science inquiry skills, facts, and concepts while focusing on the acid rain situation. Activities are organized by content areas. These include:…

  5. Acid precipitation and its influence upon aquatic ecosystems--an overview

    Science.gov (United States)

    Eville Gorham

    1976-01-01

    The impact of acid precipitation reflects a usually deleterious balance between good and bad effects which may lead to serious and sometimes extreme degradation of aquatic as well as terrestrial ecosystems, particularly around metal smelters. Addition of hydrogen ions as sulfuric, nitric, and hydrochloric acid can alter and impoverish the species composition of biotic...

  6. Risk assessment of precipitation extremes in northern Xinjiang, China

    Science.gov (United States)

    Yang, Jun; Pei, Ying; Zhang, Yanwei; Ge, Quansheng

    2017-04-01

    This study was conducted using daily precipitation records gathered at 37 meteorological stations in northern Xinjiang, China, from 1961 to 2010. We used the extreme value theory model, generalized extreme value (GEV) and generalized Pareto distribution (GPD), statistical distribution function to fit outputs of precipitation extremes with different return periods to estimate risks of precipitation extremes and diagnose aridity-humidity environmental variation and corresponding spatial patterns in northern Xinjiang. Spatiotemporal patterns of daily maximum precipitation showed that aridity-humidity conditions of northern Xinjiang could be well represented by the return periods of the precipitation data. Indices of daily maximum precipitation were effective in the prediction of floods in the study area. By analyzing future projections of daily maximum precipitation (2, 5, 10, 30, 50, and 100 years), we conclude that the flood risk will gradually increase in northern Xinjiang. GEV extreme value modeling yielded the best results, proving to be extremely valuable. Through example analysis for extreme precipitation models, the GEV statistical model was superior in terms of favorable analog extreme precipitation. The GPD model calculation results reflect annual precipitation. For most of the estimated sites' 2 and 5-year T for precipitation levels, GPD results were slightly greater than GEV results. The study found that extreme precipitation reaching a certain limit value level will cause a flood disaster. Therefore, predicting future extreme precipitation may aid warnings of flood disaster. A suitable policy concerning effective water resource management is thus urgently required.

  7. Acid precipitation and reproductive success of Ambystoma salamanders

    Science.gov (United States)

    F. Harvey Pough; Richard E. Wilson

    1976-01-01

    The two species of mole salamander that occur in the Ithaca, New York, region (Ambystoma maculatum and A. jeffersonianum) breed in temporary ponds that are formed by accumulation of melted snow and spring rains. Water in many of these pools during the breeding season is acid; pH values as low as 3.5 have been measured. In...

  8. Acidity of open and intercepted precipitation in forests

    Science.gov (United States)

    J. Baker; Drake Hocking; Marvin Nyborg

    1976-01-01

    Emissions of sulphur dioxide appear to have an acidifying effect on grossfall (open rainfall), throughfall, stemflow and soil solution at sites near major sources. Resulting effects on soil chemistry include elevated extractable acidity and aluminum and depressed exchangeable bases, especially calcium and magnesium. These changes are mostly in the incipient phases in...

  9. Reuse of washing effluent containing oxalic acid by a combined precipitation-acidification process.

    Science.gov (United States)

    Lim, Mihee; Kim, Myoung-Jin

    2013-01-01

    This study aims at evaluating the reuse feasibility of effluent produced by the soil washing of mine tailings with oxalic acid. Alkaline chemicals such as NaOH, Ca(OH)(2), and Na(2)CO(3) are used for the precipitation of arsenic and heavy metals in the effluent containing oxalic acid. All of the target contaminants are removed with very high efficiency (up to 100%) at high pH. The precipitation using NaOH at pH 9 is determined to be the most cost-effective method for the removal of arsenic as well as heavy metals in the effluent. The effluent decontaminated by NaOH is consecutively reused for the soil washing of raw mine tailings, resulting in considerable efficiency. Furthermore, even more arsenic and heavy metals are extracted from raw mine tailings by acidifying the decontaminated effluent under the alkaline condition, compared with direct reuse of the decontaminated effluent. Here, the oxalic acid, which is a weak complex-forming ligand as well as a weak acid, has noticeable effects on both soil washing and effluent treatment by precipitation. It extracts efficiently the contaminants from the mine tailings without adverse change of soil and also makes possible the precipitation of the contaminants in the effluent unlike strong chelating reagent. Reuse of the washing effluent containing oxalic acid would make the existing soil washing process more environment-friendly and cost-effective. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Calcium in milk products precipitates intestinal fatty acids and secondary bile acids and thus inhibits colonic cytotoxicity in humans

    NARCIS (Netherlands)

    Govers, MJAP; Termont, DSML; Lapre, JA; Kleibeuker, JH; Vonk, RJ; VanderMeer, R

    1996-01-01

    Dietary calcium may reduce the risk of colon cancer, probably by precipitating cytotoxic surfactants, such as secondary bile acids, in the colonic lumen. We previously showed that milk mineral, an important source of calcium, decreases metabolic risk factors and colonic proliferation in rats, We non

  11. Exploring standardized precipitation evapotranspiration index for drought assessment in Bangladesh.

    Science.gov (United States)

    Miah, Md Giashuddin; Abdullah, Hasan Muhammad; Jeong, Changyoon

    2017-10-09

    Drought is a critical issue, and it has a pressing, negative impact on agriculture, ecosystems, livelihoods, food security, and sustainability. The problem has been studied globally, but its regional or even local dimension is sometimes overlooked. Local-level drought assessment is necessary for developing adaptation and mitigation strategies for that particular region. Keeping this in understanding, an attempt was made to create a detailed assessment of drought characteristics at the local scale in Bangladesh. Standardized precipitation evapotranspiration (SPEI) is a new drought index that mainly considers the rainfall and evapotranspiration data set. Globally, SPEI has become a useful drought index, but its local scale application is not common. SPEI base (0.5° grid data) for 110 years (1901-2011) was utilized to overcome the lack of long-term climate data in Bangladesh. Available weather data (1955-2011) from Bangladesh Meteorology Department (BMD) were analyzed to calculate SPEI weather station using the SPEI calculator. The drivers for climate change-induced droughts were characterized by residual temperature and residual rainfall data from different BMD stations. Grid data (SPEI base ) of 26 stations of BMD were used for drought mapping. The findings revealed that the frequency and intensity of drought are higher in the northwestern part of the country which makes it vulnerable to both extreme and severe droughts. Based on the results, the SPEI-based drought intensity and frequency analyses were carried out, emphasizing Rangpur (northwest region) as a hot spot, to get an insight of drought assessment in Bangladesh. The findings of this study revealed that SPEI could be a valuable tool to understand the evolution and evaluation of the drought induced by climate change in the country. The study also justified the immediate need for drought risk reduction strategies that should lead to relevant policy formulations and agricultural innovations for developing

  12. Acid precipitation effects on soil pH and base saturation of exchange sites

    Science.gov (United States)

    W. W. McFee; J. M. Kelly; R. H. Beck

    1976-01-01

    The typical values and probable ranges of acid-precipitation are evaluated in terms of their theoretical effects on pH and cation exchange equilibrium of soils characteristic of the humid temperature region. The extent of probable change in soil pH and the time required to cause such a change are calculated for a range of common soils. Hydrogen ion input by acid...

  13. Potential effects of acid precipitation on soils in the humid temperate zone

    Science.gov (United States)

    C. R. Frink; G. K. Voigt

    1976-01-01

    Acid precipitation is not a new phenomenon. As long as water has fallen on the surface of the earth it has probably contained varying amounts of oxides of carbons, nitrogen and sulfur that increase hydrogen ion activity. This was certainly true when volcanism prevailed. With the appearance of life spasmodic geologic expulsions of elements into the atmosphere were...

  14. Acid precipitation and its effects on freshwater ecosystems: an annotated bibliography

    Science.gov (United States)

    Richard F. Wright

    1976-01-01

    It is especially difficult to obtain an overview of the literature on acid precipitation and its effects on freshwater ecosystems because this research covers disciplines in meteorology, chemistry, biology, geology, and hydrology. In addition, much of the work done in Scandinavia is not published in international journals and thus not included by major abstract...

  15. IMPROVEMENT UPON THE CARRIER PRECIPITATION OF PLUTONIUM IONS FROM NITRIC ACID SOLUTIONS

    Science.gov (United States)

    James, R.A.; Thompson, S.G.

    1958-12-23

    A process is reported for improving the removal of plutonlum by carrier precipitation by the addition of nitrite ions to a nitrlc acid solutlon of neutronirradiated unanium so as to destroy any hydrazine that may be present in the solution since the hydrazine tends to complex the tetravalent plutonium and prevents removal by the carrier precipltate, such as bismuth phospbate.

  16. Assessment of Satellite Precipitation Products in the Philippine Archipelago

    Science.gov (United States)

    Ramos, M. D.; Tendencia, E.; Espana, K.; Sabido, J.; Bagtasa, G.

    2016-06-01

    Precipitation is the most important weather parameter in the Philippines. Made up of more than 7100 islands, the Philippine archipelago is an agricultural country that depends on rain-fed crops. Located in the western rim of the North West Pacific Ocean, this tropical island country is very vulnerable to tropical cyclones that lead to severe flooding events. Recently, satellite-based precipitation estimates have improved significantly and can serve as alternatives to ground-based observations. These data can be used to fill data gaps not only for climatic studies, but can also be utilized for disaster risk reduction and management activities. This study characterized the statistical errors of daily precipitation from four satellite-based rainfall products from (1) the Tropical Rainfall Measuring Mission (TRMM), (2) the CPC Morphing technique (CMORPH) of NOAA and (3) the Global Satellite Mapping of Precipitation (GSMAP) and (4) Precipitation Estimation from Remotely Sensed information using Artificial Neural Networks (PERSIANN). Precipitation data were compared to 52 synoptic weather stations located all over the Philippines. Results show GSMAP to have over all lower bias and CMORPH with lowest Mean Absolute Error (MAE) and Root Mean Square Error (RMSE). In addition, a dichotomous rainfall test reveals GSMAP and CMORPH have low Proportion Correct (PC) for convective and stratiform rainclouds, respectively. TRMM consistently showed high PC for almost all raincloud types. Moreover, all four satellite precipitation showed high Correct Negatives (CN) values for the north-western part of the country during the North-East monsoon and spring monsoonal transition periods.

  17. [Low-molecular-weight organic acids in precipitation in Zunyi City, Guizhou province].

    Science.gov (United States)

    Jiang, Wei; Lee, Xin-qing; Zeng, Yong; Huang, Rong-sheng; Tan, Ling; Xu, Gang; Wang, Bing

    2008-09-01

    Formic (HCOOH) and acetic (CH3COOH) acids are ubiquitous in troposphere. Studies on the low-molecular carboxylic acids help shed light on the biogeochemical cycles of carbon, hydrogen and oxygen, as well as on the formation of acid precipitation. As a city with severe acid precipitation, the city Zunyi in north Guizhou province, provide a typical background for gaining insight into the organic geochemistry in the heavily polluted atmospheric environment. We collected the precipitation in the downtown city for a whole year on the event basis, and measured inorganic and organic anions with ion chromatograph and cations with atomic absorption spectroscopy. The data demonstrate an annual average pH of 4.11, a clear indication of the acid atmosphere. The volume-weighted mean concentrations of [HCOO-]T and [CH3COO-]T were 9.29 micromol x L(-1) (ranged from 0.15 micromol x L(-1) to 46.14 micromol x L(-1)) and 6.47 micromol x L(-1) (ranged from 0.02 micromol x L(-1) to 19.11 micromol x L(-1)) respectively, accounting for 4.10% of the total anions. With a coefficient of 0.86, formic is significantly correlated with acetic acid, suggesting that both acids share common sources. The acids often decrease with time in a precipitation event, with occasional increases in the middle and last stages, indicating that the organic acids are primarily scavenged from blow cloud, with limited amount from the long distance transportation. The close range provenance of organic acids is facilitated by the local environmental condition, which is characterized by the mountain-enclosed valley with high humidity, low wind speed, and high atmospheric dust content. Based on the Henry's Law, we proposed the ratio of formic and acetic acids in the precipitation (F/A)aq as the indicator of the sources, and thus found that the anthropogenic sources are responsible for the organic compounds in the Spring and Winter, while vegetation emissions claim the sources in the Summer and Autumn.

  18. Metal chelate affinity precipitation: purification of BSA using poly(N-vinylcaprolactam-co-methacrylic acid) copolymers.

    Science.gov (United States)

    Ling, Yuan-Qing; Nie, Hua-Li; Brandford-White, Christopher; Williams, Gareth R; Zhu, Li-Min

    2012-06-01

    This investigation involves the metal chelate affinity precipitation of bovine serum albumin (BSA) using a copper ion loaded thermo-sensitive copolymer. The copolymer of N-vinylcaprolactam with methacrylic acid PNVCL-co-MAA was synthesized by free radical polymerization in aqueous solution, and Cu(II) ions were attached to provide affinity properties for BSA. A maximum loading of 48.1mg Cu(2+) per gram of polymer was attained. The influence of pH, temperature, BSA and NaCl concentrations on BSA precipitation and of pH, ethylenediaminetetraacetic acid (EDTA) and NaCl concentrations on elution were systematically probed. The optimum conditions for BSA precipitation occurred when pH, temperature and BSA concentration were 6.0, 10°C and 1.0 mg/ml, respectively and the most favorable elution conditions were at pH 4.0, with 0.2M NaCl and 0.06 M EDTA. The maximum amounts of BSA precipitation and elution were 37.5 and 33.7 mg BSA/g polymer, respectively. It proved possible to perform multiple precipitation/elution cycles with a minimal loss of polymer efficacy. The results show that PNVCL-co-MAA is a suitable matrix for the purification of target proteins from unfractionated materials. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Advances in biotreatment of acid mine drainage and biorecovery of metals: 1. Metal precipitation for recovery and recycle.

    Science.gov (United States)

    Tabak, Henry H; Scharp, Richard; Burckle, John; Kawahara, Fred K; Govind, Rakesh

    2003-12-01

    Acid mine drainage (AMD), an acidic metal-bearing wastewater, poses a severe pollution problem attributed to post mining activities. The metals usually encountered in AMD and considered of concern for risk assessment are arsenic, cadmium, iron, lead, manganese, zinc, copper and sulfate. The pollution generated by abandoned mining activities in the area of Butte, Montana has resulted in the designation of the Silver Bow Creek-Butte Area as the largest Superfund (National Priorities List) site in the U.S. This paper reports the results of bench-scale studies conducted to develop a resource recovery based remediation process for the clean up of the Berkeley Pit. The process utilizes selective, sequential precipitation (SSP) of metals as hydroxides and sulfides, such as copper, zinc, aluminum, iron and manganese, from the Berkeley Pit AMD for their removal from the water in a form suitable for additional processing into marketable precipitates and pigments. The metal biorecovery and recycle process is based on complete separation of the biological sulfate reduction step and the metal precipitation step. Hydrogen sulfide produced in the SRB bioreactor systems is used in the precipitation step to form insoluble metal sulfides. The average metal recoveries using the SSP process were as follows: aluminum (as hydroxide) 99.8%, cadmium (as sulfide) 99.7%, cobalt (as sulfide) 99.1% copper (as sulfide) 99.8%, ferrous iron (sulfide) 97.1%, manganese (as sulfide) 87.4%, nickel (as sulfide) 47.8%, and zinc (as sulfide) 100%. The average precipitate purity for metals, copper sulfide, ferric hydroxide, zinc sulfide, aluminum hydroxide and manganese sulfide were: 92.4, 81.5, 97.8, 95.6, 92.1 and 75.0%, respectively. The final produced water contained only calcium and magnesium and both sulfate and sulfide concentrations were below usable water limits. Water quality of this agriculturally usable water met the EPA's gold standard criterion.

  20. Metal transport and remobilisation in a basin affected by acid mine drainage: the role of ochreous amorphous precipitates.

    Science.gov (United States)

    Consani, Sirio; Carbone, Cristina; Dinelli, Enrico; Balić-Žunić, Tonci; Cutroneo, Laura; Capello, Marco; Salviulo, Gabriella; Lucchetti, Gabriella

    2017-06-01

    Metal-polluted mine waters represent a major threat to the quality of waters and sediments in a downstream basin. At the confluence between acidic mine waters and the unpolluted waters of the Gromolo Torrent (Liguria, North-West Italy), the massive formation of an ochreous amorphous precipitate takes place. This precipitate forms a soft blanket that covers the torrent bed and can be observed down to its mouth in the sea. The aim of this work is to evaluate the dispersion of metals in the Gromolo Torrent basin from the abandoned Cu-Fe sulphide mine of Libiola to the Ligurian Sea and to assess the metal remobilisation from the amorphous precipitates. The mineralogy of the superficial sediments collected in the torrent bed and the concentrations of different elements of environmental concern (Cu, Zn, Cd, Co, Cr, Mn, Ni, Pb, As, and Sb) were therefore analysed. The results showed that the precipitates contain high concentration of Fe, Al, Cu, and Zn, significantly modifying the bulk chemistry of the Gromolo Torrent sediments. In order to evaluate the possible remobilisation of ecotoxic elements from the amorphous precipitates, bulk leaching tests were performed with both deionised and seawater. Bulk leaching tests with deionised water mobilised primarily high Pb amounts, but also relatively high concentrations of Fe, Al, Cu, and Zn are released in the leachate. In seawater tests, Fe, Al, Cu, and Zn were released in smaller amounts, while other elements like Mn, Cd, Co, and Ni increased in the released fraction. Pb was still strongly released as in deionised water experiments. The results show that the interaction of precipitates and seawater can remobilise high concentrations of metals, thus affecting the surrounding environment.

  1. Gas Antisolvent Approach for the Precipitation of α -Methoxyphenylacetic Acid – ( R -1-Cyclohexylethylamine Diateromeric Salt

    Directory of Open Access Journals (Sweden)

    A. Zodge

    2017-10-01

    Full Text Available One of the major drawbacks of diastereomeric salt precipitation based enantioseparation is the time and solvent requirement of crystallization. In the gas antisolvent (GAS approach, supercritical carbon dioxide is applied as an antisolvent, and the precipitation takes place in a couple of minutes. By setting the process parameters diastereomeric excess, yields, and selectivity can be controlled. Applicability of the process is demonstrated on the resolution of racemic 2-methoxyphenylacetic acid with enantiopure (R-(−-1-cyclohexylethylamine. Diastereomeric excess values over 55 % along with 80 % yields were achieved at optimal conditions in a single step.

  2. ASSESSMENT OF SATELLITE PRECIPITATION PRODUCTS IN THE PHILIPPINE ARCHIPELAGO

    Directory of Open Access Journals (Sweden)

    M. D. Ramos

    2016-06-01

    Full Text Available Precipitation is the most important weather parameter in the Philippines. Made up of more than 7100 islands, the Philippine archipelago is an agricultural country that depends on rain-fed crops. Located in the western rim of the North West Pacific Ocean, this tropical island country is very vulnerable to tropical cyclones that lead to severe flooding events. Recently, satellite-based precipitation estimates have improved significantly and can serve as alternatives to ground-based observations. These data can be used to fill data gaps not only for climatic studies, but can also be utilized for disaster risk reduction and management activities. This study characterized the statistical errors of daily precipitation from four satellite-based rainfall products from (1 the Tropical Rainfall Measuring Mission (TRMM, (2 the CPC Morphing technique (CMORPH of NOAA and (3 the Global Satellite Mapping of Precipitation (GSMAP and (4 Precipitation Estimation from Remotely Sensed information using Artificial Neural Networks (PERSIANN. Precipitation data were compared to 52 synoptic weather stations located all over the Philippines. Results show GSMAP to have over all lower bias and CMORPH with lowest Mean Absolute Error (MAE and Root Mean Square Error (RMSE. In addition, a dichotomous rainfall test reveals GSMAP and CMORPH have low Proportion Correct (PC for convective and stratiform rainclouds, respectively. TRMM consistently showed high PC for almost all raincloud types. Moreover, all four satellite precipitation showed high Correct Negatives (CN values for the north-western part of the country during the North-East monsoon and spring monsoonal transition periods.

  3. Struvite precipitation for ammonia nitrogen removal in 7-aminocephalosporanic acid wastewater.

    Science.gov (United States)

    Li, Zaixing; Ren, Xuguang; Zuo, Jiane; Liu, Yanfang; Duan, Erhong; Yang, Jingliang; Chen, Ping; Wang, Yongjun

    2012-02-21

    7-Aminocephalosporanic acid wastewater usually contains high concentrations of ammonium (NH₄⁺-N), which is known to inhibit nitrification during biological treatment processes. Chemical precipitation is a useful technology to remove ammonium from wastewater. In this paper, the removal of ammonium from 7-aminocephalosporanic acid wastewater was studied. The optimum pH, molar ratio, and various chemical compositions of magnesium ammonium phosphate (MAP) precipitation were investigated. The results indicated that ammonium in 7-aminocephalosporanic acid wastewater could be removed at an optimum pH of 9. The Mg²⁺:NH₄⁺-N:PO₄ ³⁻-P molar ratio was readily controlled at a ratio of 1:1:1.1 to both effectively remove ammonium and avoid creating a higher concentration of PO₄ ³⁻-P in the effluent. MgCl₂·6H₂O + 85% H₃PO₄ was the most efficient combination for NH₄⁺-N removal. Furthermore, the lowest concentration of the residual PO₄ ³⁻-P was obtained with the same combination. Struvite precipitation could be considered an effective technology for the NH₄⁺-N removal from the 7-aminocephalosporanic acid wastewater.

  4. Effect of amino acids on the precipitation kinetics and Ca isotopic composition of gypsum

    Science.gov (United States)

    Harouaka, Khadouja; Kubicki, James D.; Fantle, Matthew S.

    2017-12-01

    Stirred gypsum (CaSO4 · 2H2O) precipitation experiments (initial Ωgypsum = 2.4 ± 0.14, duration ≈ 1.0-1.5 h) were conducted in the presence of the amino acids glycine (190 μM), L-alanine (190 μM), D- and L-arginine (45 μM), and L-tyrosine (200 μM) to investigate the effect of simple organic compounds on both the precipitation kinetics and Ca isotopic composition of gypsum. Relative to abiotic controls, glycine, tyrosine, and alanine inhibited precipitation rates by ∼22%, 27%, and 29%, respectively, while L- and D-arginine accelerated crystal growth by ∼8% and 48%, respectively. With the exception of tyrosine, amino acid induced inhibition resulted in fractionation factors (αs-f) associated with precipitation that were no more than 0.3‰ lower than amino acid-free controls. In contrast, the tyrosine and D- and L-arginine experiments had αs-f values associated with precipitation that were similar to the controls. Our experimental results indicate that Ca isotopic fractionation associated with gypsum precipitation is impacted by growth inhibition in the presence of amino acids. Specifically, we propose that the surface-specific binding of amino acids to gypsum can change the equilibrium fractionation factor of the bulk mineral. We investigate the hypothesis that amino acids can influence the growth of gypsum at specific crystal faces via adsorption and that different faces have distinct fractionation factors (αface-fluid). Accordingly, preferential sorption of amino acids at particular faces changes the relative, face-specific mass fluxes of Ca during growth, which influences the bulk isotopic composition of the mineral. Density functional theory (DFT) calculations suggest that the energetic favorability of glycine sorption onto gypsum crystal faces occurs in the order: (1 1 0) > (0 1 0) > (1 2 0) > (0 1 1), while glycine sorption onto the (-1 1 1) face was found to be energetically unfavorable. Face-specific fractionation factors constrained by

  5. Morphologies, mechanical properties and thermal stability of poly(lactic acid) toughened by precipitated barium sulfate

    Science.gov (United States)

    Yang, Jinian; Wang, Chuang; Shao, Kaiyun; Ding, Guoxin; Tao, Yulun; Zhu, Jinbo

    2015-11-01

    Poly(lactic acid) (PLA)-based composites were prepared by blending PLA with precipitated barium sulfate (BaSO4) modified with stearic acid. The morphologies, mechanical properties and thermal stability of samples with increased mass fraction of BaSO4 were investigated. Results showed that PLA was toughened and reinforced simultaneously by incorporation of precipitated BaSO4 particles. The highest impact toughness and elongation at break were both achieved at 15% BaSO4, while the elastic modulus increased monotonically with increasing BaSO4 loading. Little effect of BaSO4 on the thermal behavior of PLA was observed in the present case. However, the thermal stability of PLA/BaSO4 composites at high temperature was enhanced.

  6. Optimal Concentration of 2,2,2-Trichloroacetic Acid for Protein Precipitation Based on Response Surface Methodology.

    Science.gov (United States)

    Ngo, Albert N; Ezoulin, Miezan Jm; Youm, Ibrahima; Youan, Bi-Botti C

    2014-09-01

    For low protein concentrations containing biological samples (in proteomics) and for non proteinaceous compound assays (in bioanalysis), there is a critical need for a simple, fast, and cost-effective protein enrichment or precipitation method. However, 2,2,2-trichloroacetic acid (TCA) is traditionally used for protein precipitation at ineffective concentrations for very low protein containing samples. It is hypothesized that response surface methodology, can be used to systematically identify the optimal TCA concentration for protein precipitation in a wider concentration range. To test this hypothesis, a central composite design is used to assess the effects of two factors (X1 = volume of aqueous solution of protein, and X2 = volume of TCA solution 6.1N) on the optical absorbance of the supernatant (Y1), and the percentage of protein precipitated (Y2). Using either bovine serum albumin (BSA) as a model protein or human urine (with 20 ppm protein content), 4% w/v (a saddle point) is the optimal concentration of the TCA solution for protein precipitation that is visualized by SDS-PAGE analysis. At this optimal concentration, the Y2-values range from 76.26 to 92.67% w/w for 0.016 to 2 mg/mL of BSA solution. It is also useful for protein enrichment and xenobiotic analysis in protein-free supernatant as applied to tenofovir (a model HIV microbicide). In these conditions, the limit of detection and limit of quantitation of tenofovir are respectively 0.0014 mg/mL and 0.0042 mg/mL. This optimal concentration of TCA provides optimal condition for protein purification and analysis of any xenobiotic compound like tenofovir.

  7. Extraction, isolation and purification of exopolysaccharide from lactic acid bacteria using ethanol precipitation method

    Directory of Open Access Journals (Sweden)

    Vivek K. Bajpai

    2016-09-01

    Full Text Available Lactic acid bacteria are classified ‘Generally Recognized As Safe’ (GRAS with most effective potential to divert significant amount of fermentable sugars towards the biosynthesis of functional exopolysaccharide. Exopolysaccharides from lactic acid bacteria are receiving a renewed interest due to the claims of human health benefits, such as modulation of immune response system and more importantly in food and pharma industries as a texturizer, viscosifer, emulsifier and syneresis-lowering agent. Its purification methodology involves: a Extraction of cell-free supernatant from lactic acid bacteria; b Denature of protein using trichloroacetic acid; c Ethanol precipitation; d Dialysis; and e Freeze drying. However, depending on nature of research, compounds can be further purified using scanning electron microscopy (SEM, infrared spectrum (IR; and nuclear magnetic resonance (NMR spectral analyses.

  8. AN ASSESSMENT OF SEVERITY OF ENVIRONMENTAL AEROSOL PARTICLES DURING PRECIPITATION

    Directory of Open Access Journals (Sweden)

    T. S. Verma

    2015-08-01

    Full Text Available Africa is one of the sources of biomass burning emissions. It is estimated that about 6 million tons of fuel per day is consumed in the southern hemisphere. Biomass burning has an important contribution on aerosol particle concentrations in the atmosphere. Efforts have been made to conduct research in Gaborone to monitor the concentration of atmospheric aerosols in atmosphere. These studies were mainly confined to measurement of concentration of aerosols and establishing a relation with determinants such as carbon dioxide concentration, biomass burning, and precipitation among others. However, very little seems to have been done in relating the empirical data to a mathematical model or to study quantitatively the impact of precipitation on the concentration of aerosols larger than 0.3?m in the atmosphere. In this paper we provide an objective criterion for classifying measurements on concentration of atmospheric aerosol particles and build a mathematical model that helps us to understand variations in weekly aerosol concentrations in terms of their severity. We also construct an index of severity which when applied to different seasons under the study period indicates that precipitation significantly scavenges atmospheric aerosols.International Journal of Environment Volume-4, Issue-3, June-August 2015Page: 81-95

  9. Potential health implications for acid precipitation, corrosion, and metals contamination of drinking water.

    Science.gov (United States)

    Sharpe, W E; DeWalle, D R

    1985-01-01

    Potential health effects of drinking water quality changes caused by acid precipitation are presented. Several different types of water supply are discussed and their roles in modifying acid rain impacts on drinking water are explained. Sources of metals contamination in surface water supplies are enumerated. The authors present some results from their research into acid rain impacts on roof-catchment cisterns, small surface water supplies, and lead mobilization in acid soils. A good correlation was obtained between cistern water corrosivity as measured by the Ryznar Index (RI) values and standing tapwater copper concentrations. However, lead concentrations in tapwater did not correlate well with cistern water RI. A modified linear regression model that accounted for Ryznar Index change during storage in vinyl-lined cisterns was used to predict the Ryznar Index value at a copper concentration of 1000 micrograms/L. The predicted RI was greater than the RI of precipitation with a pH of 5.3, indicating that anthropogenically acidified precipitation may result in cistern tapwater copper concentrations in excess of the 1000 micrograms/L suggested drinking water limit. Good correlations between tapwater Ryznar Index and tapwater copper and lead concentrations were not obtained for the small surface water supply. Aluminum concentrations in reservoir water were similar to those in stream source water. Limited data were also presented that indicated lead was present in acid forest soil leachate and streams draining such soils in relatively small concentrations. Where appropriate, recommendations for future research are included with the discussions of research results. PMID:4076096

  10. Colloidal precipitates related to Acid Mine Drainage: bacterial diversity and micro fungi-heavy metal interactions

    Science.gov (United States)

    Lucchetti, G.; Carbone, C.; Consani, S.; Zotti, M.; Di Piazza, S.; Pozzolini, M.; Giovine, M.

    2015-12-01

    In Acid Mine Drainage (AMD) settings colloidal precipitates control the mobility of Potential Toxic Elements (PTEs). Mineral-contaminant relationships (i.e. adsorption, ion-exchange, desorption) are rarely pure abiotic processes. Microbes, mainly bacteria and microfungi, can catalyze several reactions modifying the element speciation, as well as the bioavailability of inorganic pollutants. Soil, sediments, and waters heavily polluted with PTEs through AMD processes are a potential reservoir of extremophile bacteria and fungi exploitable for biotechnological purposes. Two different AMD related colloids, an ochraceous precipitate (deposited in weakly acidic conditions, composed by nanocrystalline goethite) and a greenish-blue precipitate (deposited at near-neutral pH, composed by allophane + woodwardite) were sampled. The aims of this work were to a) characterize the mycobiota present in these colloidal minerals by evaluating the presence of alive fungal propagules and extracting bacteria DNA; b) verify the fungal strains tolerance, and bioaccumulation capability on greenish-blue and ZnSO4 enriched media; c) evaluate potential impact of bacteria in the system geochemistry. The preliminary results show an interesting and selected mycobiota able to survive under unfavourable environmental conditions. A significant number of fungal strains were isolated in pure culture. Among them, species belonging to Penicillium and Trichoderma genera were tested on both greenish-blue and ZnSO4 enriched media. The results show a significant tolerance and bioaccumulation capability to some PTEs. The same colloidal precipitates were processed to extract bacteria DNA by using a specific procedure developed for sediments. The results give a good yield of nucleic acids and a positive PCR amplification of 16S rDNA accomplished the first step for future metagenomic analyses.

  11. Online Assessment of Satellite-Derived Global Precipitation Products

    Science.gov (United States)

    Liu, Zhong; Ostrenga, D.; Teng, W.; Kempler, S.

    2012-01-01

    Precipitation is difficult to measure and predict. Each year droughts and floods cause severe property damages and human casualties around the world. Accurate measurement and forecast are important for mitigation and preparedness efforts. Significant progress has been made over the past decade in satellite precipitation product development. In particular, products' spatial and temporal resolutions as well as timely availability have been improved by blended techniques. Their resulting products are widely used in various research and applications. However biases and uncertainties are common among precipitation products and an obstacle exists in quickly gaining knowledge of product quality, biases and behavior at a local or regional scale, namely user defined areas or points of interest. Current online inter-comparison and validation services have not addressed this issue adequately. To address this issue, we have developed a prototype to inter-compare satellite derived daily products in the TRMM Online Visualization and Analysis System (TOVAS). Despite its limited functionality and datasets, users can use this tool to generate customized plots within the United States for 2005. In addition, users can download customized data for further analysis, e.g. comparing their gauge data. To meet increasing demands, we plan to increase the temporal coverage and expanded the spatial coverage from the United States to the globe. More products have been added as well. In this poster, we present two new tools: Inter-comparison of 3B42RT and 3B42 Inter-comparison of V6 and V7 TRMM L-3 monthly products The future plans include integrating IPWG (International Precipitation Working Group) Validation Algorithms/statistics, allowing users to generate customized plots and data. In addition, we will expand the current daily products to monthly and their climatology products. Whenever the TRMM science team changes their product version number, users would like to know the differences by

  12. Comparison of Precipitated Calcium Carbonate/Polylactic Acid and Halloysite/Polylactic Acid Nanocomposites

    OpenAIRE

    Xuetao Shi; Guangcheng Zhang; Cristina Siligardi; Guido Ori; Andrea Lazzeri

    2015-01-01

    PLA nanocomposites with stearate coated precipitated calcium carbonate (PCC) and halloysite natural nanotubes (HNT) were prepared by melt extrusion. The crystallization behavior, mechanical properties, thermal dynamical mechanical analysis (DMTA), and the morphology of the PCC/PLA, HNT/PLA, and HNT/PCC/PLA composites were discussed. Compared to halloysite nanotubes, PCC nanoparticles showed a better nucleating effect, which decreased both the glass transition and cold crystallization temperat...

  13. Particle size tailoring of ursolic acid nanosuspensions for improved anticancer activity by controlled antisolvent precipitation.

    Science.gov (United States)

    Wang, Yancai; Song, Ju; Chow, Shing Fung; Chow, Albert H L; Zheng, Ying

    2015-10-15

    The present study was aimed at tailoring the particle size of ursolic acid (UA) nanosuspension for improved anticancer activity. UA nanosuspensions were prepared by antisolvent precipitation using a four-stream multi-inlet vortex mixer (MIVM) under defined conditions of varying solvent composition, drug feeding concentration or stream flow rate. The resulting products were characterized for particle size and polydispersity. Two of the UA nanosuspensions with mean particle sizes of 100 and 300 nm were further assessed for their in-vitro activity against MCF-7 breast cancer cells using fluorescence microscopy with 4',6-diamidino-2-phenylindole (DAPI) staining, as well as flow cytometry with propidium (PI) staining and with double staining by fluorescein isothiocyanate. It was revealed that the solvent composition, drug feeding concentration and stream flow rate were critical parameters for particle size control of the UA nanosuspensions generated with the MIVM. Specifically, decreasing the UA feeding concentration or increasing the stream flow rate or ethanol content resulted in a reduction of particle size. Excellent reproducibility for nanosuspension production was demonstrated for the 100 and 300 nm UA preparations with a deviation of not more than 5% in particle size from the mean value of three independent batches. Fluorescence microscopy and flow cytometry revealed that these two different sized UA nanosuspensions, particularly the 300 nm sample, exhibited a higher anti-proliferation activity against the MCF-7 cells and afforded a larger population of these cells in both early and late apoptotic phases. In conclusion, MIVM is a robust and pragmatic tool for tailoring the particle size of the UA nanosuspension. Particle size appears to be a critical determinant of the anticancer activity of the UA nanoparticles. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. An Assessment of Mean Areal Precipitation Methods on Simulated Stream Flow: A SWAT Model Performance Assessment

    Directory of Open Access Journals (Sweden)

    Sean Zeiger

    2017-06-01

    Full Text Available Accurate mean areal precipitation (MAP estimates are essential input forcings for hydrologic models. However, the selection of the most accurate method to estimate MAP can be daunting because there are numerous methods to choose from (e.g., proximate gauge, direct weighted average, surface-fitting, and remotely sensed methods. Multiple methods (n = 19 were used to estimate MAP with precipitation data from 11 distributed monitoring sites, and 4 remotely sensed data sets. Each method was validated against the hydrologic model simulated stream flow using the Soil and Water Assessment Tool (SWAT. SWAT was validated using a split-site method and the observed stream flow data from five nested-scale gauging sites in a mixed-land-use watershed of the central USA. Cross-validation results showed the error associated with surface-fitting and remotely sensed methods ranging from −4.5 to −5.1%, and −9.8 to −14.7%, respectively. Split-site validation results showed the percent bias (PBIAS values that ranged from −4.5 to −160%. Second order polynomial functions especially overestimated precipitation and subsequent stream flow simulations (PBIAS = −160 in the headwaters. The results indicated that using an inverse-distance weighted, linear polynomial interpolation or multiquadric function method to estimate MAP may improve SWAT model simulations. Collectively, the results highlight the importance of spatially distributed observed hydroclimate data for precipitation and subsequent steam flow estimations. The MAP methods demonstrated in the current work can be used to reduce hydrologic model uncertainty caused by watershed physiographic differences.

  15. Histone-dependent IgG conservation in octanoic acid precipitation and its mechanism.

    Science.gov (United States)

    Chen, Quan; Toh, Phyllicia; Sun, Yue; Latiff, Sarah Maria Abdul; Hoi, Aina; Xian, Mo; Zhang, Haibo; Nian, Rui; Zhang, Wei; Gagnon, Pete

    2016-12-01

    Octanoic acid (OA) precipitation has long been used in protein purification. Recently, we reported a new cell culture clarification method for immunoglobulin G (IgG) purification, employing an advance elimination of chromatin heteroaggregates with a hybrid OA-solid phase system. This treatment reduced DNA more than 3 logs, histone below the detection limit (LOD), and non-histone host cell proteins (nh-HCP) by 90 % while conserving more than 90 % of the IgG monomer. In this study, we further investigated the conservation of IgG monomer and antibody light chain (LC) to the addition of OA/OA-solid phase complex, with or without histone and DNA in different combinations. The results showed that highly basic histone protein was the prime target in OA/OA-solid phase precipitation system for IgG purification, and the selective conservation of IgG monomer in this system was histone dependent. Our findings partially support the idea that OA works by sticking to electropositive hydrophobic domains on proteins, reducing their solubility, and causing them to agglomerate into large particles that precipitate from solution. Our findings also provide a new perspective for IgG purification and emphasize the necessity to re-examine the roles of various host contaminants in IgG purification.

  16. Accuracy assessment of gridded precipitation datasets in the Upper Indus Basin

    Science.gov (United States)

    Khan, Asif; Masud, Tabinda; Attaullah, Haleema; Khan, Mujahid

    2017-04-01

    Accurate precipitation data are vital for hydro-climatic modelling and water resources assessments. Based on mass balance calculations and Turc-Budyko analysis, this study investigates the accuracy of thirteen widely used precipitation gridded datasets for sub-basins in the Upper Indus Basin (UIB) in the Himalayas-Karakoram-Hindukush (HKH) region. These datasets are: 1) Global Precipitation Climatology Project (GPCP), 2) Climate Prediction Centre (CPC) Merged Analysis of Precipitation (CMAP), 3) National Centers for Environmental Prediction (NCEP) / National Center for Atmospheric Research (NCAR), 4) Global Precipitation Climatology Centre (GPCC), 5) Climatic Research Unit (CRU), 6) Asian Precipitation Highly Resolved Observational Data Integration Towards Evaluation of Water Resources (APHRODITE), 7) Tropical Rainfall Measuring Mission (TRMM), 8) European Reanalysis (ERA) interim, 9) PRINCETON, 10) European Reanalysis-40 (ERA-40), 11) Willmott and Matsuura, 12) WATCH Forcing Data based on ERA interim (WFDEI), and 13) the Japanese 55-year Reanalysis (JRA-55) data. Precipitation accuracy and consistency was assessed by physical mass balance involving sum of annual measured flow, estimated actual evapotranspiration (average of 4 datasets), estimated glacier mass balance melt contribution (average of 4 datasets), and ground water recharge (average of 3 datasets), during 1999-2010. Mass balance assessment was complemented by Turc-Budyko non-dimensional analysis, where annual precipitation, measured flow and potential evapotranspiration (average of 5 datasets) data were used for the same period. Both analyses suggest that all tested precipitation datasets significantly under-estimate precipitation in the Karakoram sub-basins, except JRA-55 data. For the Hindukush and Himalayan sub-basins most datasets under-estimate precipitation except all Reanalysis datasets. The analysis indicates that for this large region with complicated terrain features and stark spatial

  17. Dissolved total hydrolyzable enantiomeric amino acids in precipitation: Implications on bacterial contributions to atmospheric organic matter

    Science.gov (United States)

    Yan, Ge; Kim, Guebuem; Kim, Jeonghyun; Jeong, Yu-Sik; Kim, Young Il

    2015-03-01

    We analyzed dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and dissolved enantiomeric amino acids in precipitation samples collected at two sites in Korea over a one-year period. The average concentrations of DOC, DON, and total hydrolyzable amino acids at Seoul (an inland urban area) were lower than those at Uljin (a coastal rural area). The different bulk compositions of dissolved organic matter (DOM) at these two sites (reflected by qualitative indicators) were mainly attributed to differences in contributing sources. The D-enantiomers of four individual amino acids (aspartic acid, glutamic acid, serine, and alanine) were ubiquitously present, with average enantiomeric (D/L) ratios of 0.34, 0.26, 0.21, and 0.61 for Seoul, and 0.18, 0.11, 0.09, and 0.31 for Uljin, respectively. The much higher D/L ratios observed at Seoul than at Uljin might result from more advanced diagenetic stages as well as higher contributions from bacteria inhabiting terrestrial environments. The C- and N-normalized yields of D-alanine in DOM of our samples were found to be comparable to literature values reported for aquatic systems, where a significant portion of DOM was suggested to be of bacterial origin. Our study suggests that bacteria and their remnants might constitute an important fraction of OM in the atmosphere, contributing significantly to the quality of atmospheric OM and its post-depositional bioavailability in the surface ecosystems.

  18. Boronic Acid functionalized core-shell polymer nanoparticles prepared by distillation precipitation polymerization for glycopeptide enrichment.

    Science.gov (United States)

    Qu, Yanyan; Liu, Jianxi; Yang, Kaiguang; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2012-07-16

    The boronic acid-functionalized core-shell polymer nanoparticles, poly(N,N-methylenebisacrylamide-co-methacrylic acid)@4-vinylphenylboronic acid (poly(MBA-co-MAA)@VPBA), were successfully synthesized for enriching glycosylated peptides. Such nanoparticles were composed of a hydrophilic polymer core prepared by distillation precipitation polymerization (DPP) and a boronic acid-functionalized shell designed for capturing glycopeptides. Owing to the relatively large amount of residual vinyl groups introduced by DPP on the core surface, the VPBA monomer was coated with high efficiency, working as the shell. Moreover, the overall polymerization route, especially the use of DPP, made the synthesis of nanoparticles facile and time-saving. With the poly(MBA-co-MAA)@VPBA nanoparticles, 18 glycopeptides from horseradish peroxidase (HRP) digest were captured and identified by MALDI-TOF mass spectrometric analysis, relative to eight glycopeptides enriched by using commercially available meta-aminophenylboronic acid agarose under the same conditions. When the concentration of the HRP digest was decreased to as low as 5 nmol, glycopeptides could still be selectively isolated by the prepared nanoparticles. Our results demonstrated that the synthetic poly(MBA-co-MAA)@VPBA nanoparticles might be a promising selective enrichment material for glycoproteome analysis. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Biogenic precipitation of manganese oxides and enrichment of heavy metals at acidic soil pH

    Science.gov (United States)

    Mayanna, Sathish; Peacock, Caroline L.; Schäffner, Franziska; Grawunder, Anja; Merten, Dirk; Kothe, Erika; Büchel, Georg

    2014-05-01

    The precipitation of biogenic Mn oxides at acidic pH is rarely reported and poorly understood, compared to biogenic Mn oxide precipitation at near neutral conditions. Here we identified and investigated the precipitation of biogenic Mn oxides in acidic soil, and studied their role in the retention of heavy metals, at the former uranium mining site of Ronneburg, Germany. The site is characterized by acidic pH, low carbon content and high heavy metal loads including rare earth elements. Specifically, the Mn oxides were present in layers identified by detailed soil profiling and within these layers pH varied from 4.7 to 5.1, Eh varied from 640 to 660 mV and there were enriched total metal contents for Ba, Ni, Co, Cd and Zn in addition to high Mn levels. Using electron microprobe analysis, synchrotron X-ray diffraction and X-ray absorption spectroscopy, we identified poorly crystalline birnessite (δ-MnO2) as the dominant Mn oxide in the Mn layers, present as coatings covering and cementing quartz grains. With geochemical modelling we found that the environmental conditions at the site were not favourable for chemical oxidation of Mn(II), and thus we performed 16S rDNA sequencing to isolate the bacterial strains present in the Mn layers. Bacterial phyla present in the Mn layers belonged to Firmicutes, Actinobacteria and Proteobacteria, and from these phyla we isolated six strains of Mn(II) oxidizing bacteria and confirmed their ability to oxidise Mn(II) in the laboratory. The biogenic Mn oxide layers act as a sink for metals and the bioavailability of these metals was much lower in the Mn layers than in adjacent layers, reflecting their preferential sorption to the biogenic Mn oxide. In this presentation we will report our findings, concluding that the formation of natural biogenic poorly crystalline birnessite can occur at acidic pH, resulting in the formation of a biogeochemical barrier which, in turn, can control the mobility and bioavailability of heavy metals in

  20. Microscopic evaluation of trace metals in cloud droplets in an acid precipitation region.

    Science.gov (United States)

    Li, Weijun; Wang, Yan; Collett, Jeffrey L; Chen, Jianmin; Zhang, Xiaoye; Wang, Zifa; Wang, Wenxing

    2013-05-07

    Mass concentrations of soluble trace metals and size, number, and mixing properties of nanometal particles in clouds determine their toxicity to ecosystems. Cloud water was found to be acidic, with a pH of 3.52, at Mt. Lu (elevation 1,165 m) in an acid precipitation region in South China. A combination of Inductively Coupled Plasma Mass Spectrometry (ICPMS) and Transmission Electron Microscopy (TEM) for the first time demonstrates that the soluble metal concentrations and solid metal particle number are surprisingly high in acid clouds at Mt. Lu, where daily concentrations of SO2, NO2, and PM10 are 18 μg m(-3), 7 μg m(-3), and 22 μg m(-3). The soluble metals in cloudwater with the highest concentrations were zinc (Zn, 200 μg L(-1)), iron (Fe, 88 μg L(-1)), and lead (Pb, 77 μg L(-1)). TEM reveals that 76% of cloud residues include metal particles that range from 50 nm to 1 μm diameter with a median diameter of 250 nm. Four major metal-associated particle types are Pb-rich (35%), fly ash (27%), Fe-rich (23%), and Zn-rich (15%). Elemental mapping shows that minor soluble metals are distributed within sulfates of cloud residues. Emissions of fine metal particles from large, nonferrous industries and coal-fired power plants with tall stacks were transported upward to this high elevation. Our results suggest that the abundant trace metals in clouds aggravate the impacts of acid clouds or associated precipitation on the ecosystem and human health.

  1. Effectiveness of coagulation and acid precipitation processes for the pre-treatment of diluted black liquor.

    Science.gov (United States)

    Garg, Anurag; Mishra, I M; Chand, S

    2010-08-15

    The effectiveness of coagulation (using aluminium-based chemicals and ferrous sulfate) and acid precipitation (using H(2)SO(4)) processes for the pre-treatment of diluted black liquor obtained from a pulp and paper mill is reported. Commercial alum was found to be the most economical among all the aluminium and ferrous salts used as a coagulant. A maximum removal of chemical oxygen demand (COD) (ca. 63%) and colour reduction (ca. 90%) from the wastewater (COD = 7000 mg l(-1)) at pH 5.0 was obtained with alum. During the acid precipitation process, at pH < 5.0, significant COD reductions (up to 64%) were observed. Solid residue obtained from the alum treatment at a temperature of 95 degrees C showed much better (3 times) settling rate than that for the residue obtained after treatment with the same coagulant at a temperature of 25 degrees C. The settling curves had three parts, namely, hindered, transition and compression zones. Tory plots were used to determine the critical height of suspension-supernatant interface that is used in the design of a clarifier-thickener unit. High heating values and large biomass fraction of the solid residues can encourage the fuel users to use this waste derived sludge as a potential renewable energy source. Copyright 2010 Elsevier B.V. All rights reserved.

  2. Design of Test Facility to Evaluate Boric Acid Precipitation Following a LOCA

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Jeong-Kwan; Song, Yong-Jae [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    The U.S.NRC has identified a concern that debris associated with generic safety issue (GSI) - 191 may affect the potential precipitation of boric acid due to one or more of the following phenomena: - Reducing mass transport (i.e. mixing) between the core and the lower plenum (should debris accumulate at the core inlet) - Reduced lower plenum volume (should debris settle in the lower plenum), and, - Increased potential for boric acid precipitation (BAP) in the core (should debris accumulate in suspension in the core) To address these BAP issues, KHNP is planning to conduct validation tests by constructing a BAP test facility. This paper describes the design of test facility to evaluate BAP following a LOCA. The design of BAP test facility has been developed by KHNP. To design the test facility, test requirements and success criteria were established, and scaling analysis of power-to-volume method, Ishii-Kataoka method, and hierarchical two-tiered method were investigated. The test section is composed of two fuel assemblies with half of full of prototypic FA height. All the fuel rods are heated by the electric power supplier. The BAP tests in the presence of debris, buffering agents, and boron will be performed following the test matrix.

  3. Precipitation interpolation and corresponding uncertainty assessment using copulas

    Science.gov (United States)

    Bardossy, A.; Pegram, G. G.

    2012-12-01

    Spatial interpolation of rainfall over different time and spatial scales is necessary in many applications of hydrometeorology. The specific problems encountered in rainfall interpolation include: the large number of calculations which need to be performed automatically the quantification of the influence of topography, usually the most influential of exogenous variables how to use observed zero (dry) values in interpolation, because their proportion increases the shorter the time interval the need to estimate a reasonable uncertainty of the modelled point/pixel distributions the need to separate (i) temporally highly correlated bias from (ii) random interpolation errors at different spatial and temporal scales the difficulty of estimating uncertainty of accumulations over a range of spatial scales. The approaches used and described in the presentation employ the variables rainfall and altitude. The methods of interpolation include (i) Ordinary Kriging of the rainfall without altitude, (ii) External Drift Kriging with altitude as an exogenous variable, and less conventionally, (iii) truncated Gaussian copulas and truncated v-copulas, both omitting and including the altitude of the control stations as well as that of the target (iv) truncated Gaussian copulas and truncated v-copulas for a two-step interpolation of precipitation combining temporal and spatial quantiles for bias quantification. It was found that truncated Gaussian copulas, with the target's and all control the stations' altitudes included as exogenous variables, produce the lowest Mean Square error in cross-validation and, as a bonus, model with the least bias. In contrast, the uncertainty of interpolation is better described by the v-copulas, but the Gaussian copulas have the advantage of computational effort (by three orders of magnitude) which justifies their use in practice. It turns out that the uncertainty estimates of the OK and EDK interpolants are not competitive at any time scale, from daily

  4. Comparison of Precipitated Calcium Carbonate/Polylactic Acid and Halloysite/Polylactic Acid Nanocomposites

    Directory of Open Access Journals (Sweden)

    Xuetao Shi

    2015-01-01

    Full Text Available PLA nanocomposites with stearate coated precipitated calcium carbonate (PCC and halloysite natural nanotubes (HNT were prepared by melt extrusion. The crystallization behavior, mechanical properties, thermal dynamical mechanical analysis (DMTA, and the morphology of the PCC/PLA, HNT/PLA, and HNT/PCC/PLA composites were discussed. Compared to halloysite nanotubes, PCC nanoparticles showed a better nucleating effect, which decreased both the glass transition and cold crystallization temperatures. The tensile performance of PLA composites showed that the addition of inorganic nanofillers increased Young’s modulus but decreased tensile strength. More interestingly, PLA composites with PCC particles exhibited an effectively increased elongation at break with respect to pure PLA, while HNT/PLA showed a decreased ultimate deformation of composites. DMTA results indicated that PLA composites had a similar storage modulus at temperatures below the glass transition and the addition of nanofillers into PLA caused Tg to shift to lower temperatures by about 3°C. The morphological analysis of fractures surface of PLA nanocomposites showed good dispersion of nanofillers, formation of microvoids, and larger plastic deformation of the PLA matrix when the PCC particles were added, while a strong aggregation was noticed in composites with HNT nanofillers, which has been attributed to a nonoptimal surface coating.

  5. Effects of initial supersaturation on spontaneous precipitation of calcium carbonate in the presence of charged poly-L-amino acids.

    Science.gov (United States)

    Njegić-Dzakula, Branka; Falini, Giuseppe; Brecević, Ljerka; Skoko, Zeljko; Kralj, Damir

    2010-03-15

    Spontaneous precipitation of calcium carbonate was investigated in two precipitation systems: (1) with initial supersaturation lower than that corresponding to the solubility of amorphous calcium carbonate (ACC), at which vaterite precipitated, and (2) with initial supersaturation higher than that of ACC solubility, at which a mixture of calcite and vaterite was formed. After the addition of an acidic polypeptide, poly-L-glutamic acid (pGlu) or poly-L-aspartic acid (pAsp), into (1) a significant inhibition of nucleation, expressed as an increase in induction time, and growth of vaterite, perceived as a dead zone, was observed. Extent of inhibition decreased in the order: Inh(pAps)>Inh(pGlu)>Inh(pLys). The addition of a polypeptide into (2) caused the inhibition of precipitation and changed the morphology and polymorphic composition of the precipitate; only vaterite appeared at approximately c(pAsp)=3 ppm, c(pGlu)=6 ppm, or c(pLys)=7 ppm. This finding is explained as a consequence of kinetic constraints through the inhibition of calcite nucleation and stronger binding of acidic polypeptide by the calcite surfaces than by the vaterite surfaces. Laboratory precipitation studies using conditions that resemble those in living organism should be run at an initial supersaturation corresponding to the solubility of ACC as a limiting condition. 2009 Elsevier Inc. All rights reserved.

  6. Long Term Precipitation Patterns Assessment and Prediction over the Mediterranean Basin

    Science.gov (United States)

    Elkadiri, R.; Sultan, M.; Momm, H.; Elbayoumi, T.; Milewski, A.; Blair, Z.; Briana, V.

    2016-12-01

    We developed and applied an integrated approach to construct predictive tools with lead times of 1 to 24 months to forecast monthly precipitation amounts over the Mediterranean Basin. The study was applied over eight climatically different and homogeneous pilot sites. The following steps were conducted: (1) acquire, assess and inter-correlate temporal remote sensing-based precipitation products (e.g. The CPC Merged Analysis of Precipitation [CMAP], Integrated Multi-Satellite Retrievals for GPM [IMERG]) throughout the investigation period (1980 to 2016), (2) acquire and assess monthly values for all of the climatic indices influencing the regional and global climatic patterns (e.g., Northern Atlantic Oscillation [NOI], Southern Oscillation Index [SOI], and Tropical North Atlantic Index [TNA]); and (3) apply data mining methods (e.g. neural networks, genetic algorithms) to extract relationships between the observed precipitation and the controlling factors (i.e. climatic indices with multiple lead-time periods) and use predictive tools to forecast monthly precipitation. Preliminary results indicate that by using the period from January 2006 until January 2016 for model testing and the period from January 1980 until December 2005 for model training, precipitation can be successfully predicted with lead times from 1 to 24 months over the test sites with an accuracy ranging between 52% and 98%. If our final efforts are successful, our findings could lead the way to the development and implementation of long-term water management scenarios for the Mediterranean region.

  7. Assessment of CORDEX-South Asia experiments for monsoonal precipitation over Himalayan region for future climate

    Science.gov (United States)

    Choudhary, A.; Dimri, A. P.

    2017-07-01

    Precipitation is one of the important climatic indicators in the global climate system. Probable changes in monsoonal (June, July, August and September; hereafter JJAS) mean precipitation in the Himalayan region for three different greenhouse gas emission scenarios (i.e. representative concentration pathways or RCPs) and two future time slices (near and far) are estimated from a set of regional climate simulations performed under Coordinated Regional Climate Downscaling Experiment-South Asia (CORDEX-SA) project. For each of the CORDEX-SA simulations and their ensemble, projections of near future (2020-2049) and far future (2070-2099) precipitation climatology with respect to corresponding present climate (1970-2005) over Himalayan region are presented. The variability existing over each of the future time slices is compared with the present climate variability to determine the future changes in inter annual fluctuations of monsoonal mean precipitation. The long-term (1970-2099) trend (mm/day/year) of monsoonal mean precipitation spatially distributed as well as averaged over Himalayan region is analyzed to detect any change across twenty-first century as well as to assess model uncertainty in simulating the precipitation changes over this period. The altitudinal distribution of difference in trend of future precipitation from present climate existing over each of the time slices is also studied to understand any elevation dependency of change in precipitation pattern. Except for a part of the Hindu-Kush area in western Himalayan region which shows drier condition, the CORDEX-SA experiments project in general wetter/drier conditions in near future for western/eastern Himalayan region, a scenario which gets further intensified in far future. Although, a gradually increasing precipitation trend is seen throughout the twenty-first century in carbon intensive scenarios, the distribution of trend with elevation presents a very complex picture with lower elevations

  8. Recovery of Vanadium from H2SO4-HF Acidic Leaching Solution of Black Shale by Solvent Extraction and Precipitation

    OpenAIRE

    Xingbin Li; Chang Wei; Zhigan Deng; Cunxiong Li; Gang Fan; Minting Li; Hui Huang

    2016-01-01

    The recovery of vanadium from sulfuric and hydrofluoric mixed acid solutions generated by the direct leaching of black shale was investigated using solvent extraction and precipitation methods. The process consisted of reduction, solvent extraction, and stripping, followed by precipitation and calcination to yield vanadium pentoxide. The influence of various operating parameters on the extraction and recovery of vanadium was studied. Vanadium (IV) was selectively extracted using a mixture of ...

  9. Preparation and characterization of micronized ellagic acid using antisolvent precipitation for oral delivery.

    Science.gov (United States)

    Li, Yong; Zhao, Xiuhua; Zu, Yuangang; Zhang, Yin; Ge, Yunlong; Zhong, Chen; Wu, Weiwei

    2015-01-01

    In this work, poorly water soluble phytochemical ellagic acid (EA) was micronized to increase its solubility and thereby the bioavailability during antisolvent precipitation process using N-methyl pyrrolidone (NMP) as solvent and deionized water as antisolvent. The micronized EA (m-EA) freeze-dried powder was prepared by the subsequent lyophilization process. The effects of various experimental parameters on the mean particle size (MPS) of m-EA suspension (m-EAS) in the antisolvent precipitation process were investigated. MPS and production efficiency were taken into account comprehensively to obtain the optimum conditions of antisolvent precipitation. Under the optimum conditions, m-EA freeze-dried powder with a MPS of 429.2 ± 7.6 nm was obtained. The physico-chemical properties of m-EA freeze-dried powder were detected by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), liquid chromatography-tandem mass spectrometry (LC-MS/MS), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results indicated m-EA kept the same chemical structure with raw EA, but the crystallinity was greatly reduced. Furthermore, a comparison of the 50% inhibition concentration (IC50) values revealed that m-EA was more effective than raw EA in scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. Meanwhile, m-EA also showed higher reducing power. Moreover, the residual amount of NMP was lower than the International Conference on Harmonization limit (530 ppm) for solvents. The dissolution rate of m-EA was approximately 2 times of raw EA. Moreover, the solubility of m-EA was about 6.5 times of raw EA. Meanwhile, the bioavailability of m-EA increased about 2 times compared with raw EA via oral administration. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Modeling the impact of energetic particle precipitation on stratospheric nitric acid polar enhancements using WACCM

    Science.gov (United States)

    Orsolini, Yvan; Kvissel, Ole Kristian; Stordal, Frode

    The wintertime abundance of nitric acid (HNO3) in the polar upper stratosphere displays a strong inter-annual variability. It is known to be strongly influenced by energetic particle precipitation, not only on a fast time scale by solar proton events, but also on a slower time scale by descent of mesospheric air enriched in NOx by precipitating electrons. Measurements by SMR aboard the Odin satellite, by MIPAS aboard the ENVISAT satellite, or by MLS aboard the Aura satellite, have shown occasional enhancements in excess of 10 ppb, leading to a double-peaked HNO3 profile with a secondary maximum descending from the upper stratosphere. N2O5 heterogeneous conversion upon hydrated ion clusters has long been proposed as the likely mechanism for the slower effect. Here we introduce this predominantly wintertime source of HNO3 in the NCAR Whole Atmo-sphere Community Climate Model (WACCM version 3.1.9) as a pseudo first-order reaction, assuming a simple, temporarily fixed, meridional distribution of hydrated ion clusters. The 4-year simulation is compared to a control one, with the new reaction omitted. Realistic enhancements of HNO3 are produced when air masses with high level of NOx descend into the stratosphere during the long polar night. As HNO3 is a key component influencing the stratospheric ozone distribution, complex chemical but also radiative and dynamical feedbacks appear, which impact in particular the ozone depletion in the southern hemisphere spring, and the NOx distribution in summer high latitudes.

  11. Assessing the performance of satellite-based precipitation products over the Mediterranean region

    Science.gov (United States)

    Xaver, Angelika; Dorigo, Wouter; Brocca, Luca; Ciabatta, Luca

    2017-04-01

    Detailed knowledge about the spatial and temporal patterns and quantities of precipitation is of high importance. This applies especially in the Mediterranean region, where water demand for agricultural, industrial and touristic needs is growing and climate projections foresee a decrease of precipitation amounts and an increase in variability. In this region, ground-based rain gauges are available only limited in number, particularly in northern Africa and the Middle East and lack to capture the high spatio-temporal character of precipitation over large areas. This has motivated the development of a large number of remote sensing products for monitoring rainfall. Satellite-based precipitation products are based on various observation principles and retrieval approaches, i.e. from thermal infra-red and microwaves. Although, many individual validation studies on the performance of these precipitation datasets exist, they mostly examine only one or a few of these rainfall products at the same time and are not targeted at the Mediterranean basin as a whole. Here, we present an extensive comparative study of seven different satellite-based precipitation products, namely CMORPH 30-minutes, CMORPH 3-hourly, GPCP, PERSIANN, SM2Rain CCI, TRMM TMPA 3B42, and TRMM TMPA 3B42RT, focusing on the whole Mediterranean region and on individual Mediterranean catchments. The time frame of investigation is restricted by the common availability of all precipitation products and covers the period 2000-2013. We assess the skill of the satellite products against gridded gauge-based data provided by GPCC and E-OBS. Apart from common characteristics like biases and temporal correlations we evaluate several sophisticated dataset properties that are of particular interest for Mediterranean hydrology, including the capability of the remotely sensed products to capture extreme events and trends. A clear seasonal dependency of the correlation results can be observed for the whole Mediterranean

  12. Strong and Biostable Hyaluronic Acid-Calcium Phosphate Nanocomposite Hydrogel via in Situ Precipitation Process.

    Science.gov (United States)

    Jeong, Seol-Ha; Koh, Young-Hag; Kim, Suk-Wha; Park, Ji-Ung; Kim, Hyoun-Ee; Song, Juha

    2016-03-14

    Hyaluronic acid (HAc) hydrogel exhibits excellent biocompatibility, but it has limited biomedical application due to its poor biomechanical properties as well as too-fast enzymatic degradation. In this study, we have developed an in situ precipitation process for the fabrication of a HAc-calcium phosphate nanocomposite hydrogel, after the formation of the glycidyl methacrylate-conjugated HAc (GMHA) hydrogels via photo-cross-linking, to improve the mechanical and biological properties under physiological conditions. In particular, our process facilitates the rapid incorporation of calcium phosphate (CaP) nanoparticles of uniform size and with minimal agglomeration into a polymer matrix, homogeneously. Compared with pure HAc, the nanocomposite hydrogels exhibit improved mechanical behavior. Specifically, the shear modulus is improved by a factor of 4. The biostability of the nanocomposite hydrogel was also significantly improved compared with that of pure HAc hydrogels under both in vitro and in vivo conditions.

  13. Assessment and Comparison of TMPA Satellite Precipitation Products in Varying Climatic and Topographic Regimes in Morocco

    Directory of Open Access Journals (Sweden)

    Adam Milewski

    2015-05-01

    Full Text Available TRMM Multi-satellite Precipitation Analysis (TMPA satellite precipitation products have been utilized to quantify, forecast, or understand precipitation patterns, climate change, hydrologic models, and drought in numerous scientific investigations. The TMPA products recently went through a series of algorithm developments to enhance the accuracy and reliability of high-quality precipitation measurements, particularly in low rainfall environments and complex terrain. In this study, we evaluated four TMPA products (3B42: V6, V7temp, V7, RTV7 against 125 rain gauges in Northern Morocco to assess the accuracy of TMPA products in various regimes, examine the performance metrics of new algorithm developments, and assess the impact of the processing error in 2012. Results show that the research products outperform the real-time products in all environments within Morocco, and the newest algorithm development (3B42 V7 outperforms the previous version (V6, particularly in low rainfall and high-elevation environments. TMPA products continue to overestimate precipitation in arid environments and underestimate it in high-elevation areas. Lastly, the temporary processing error resulted in little bias except in arid environments. These results corroborate findings from previous studies, provide scientific data for the Middle East, highlight the difficulty of using TMPA products in varying conditions, and present preliminary research for future algorithm development for the GPM mission.

  14. A simple procedure for preparing chitin oligomers through acetone precipitation after hydrolysis in concentrated hydrochloric acid.

    Science.gov (United States)

    Kazami, Nao; Sakaguchi, Masayoshi; Mizutani, Daisuke; Masuda, Tatsuhiko; Wakita, Satoshi; Oyama, Fumitaka; Kawakita, Masao; Sugahara, Yasusato

    2015-11-05

    Chitin oligomers are of interest because of their numerous biologically relevant properties. To prepare chitin oligomers containing 4-6 GlcNAc units [(GlcNAc)4-6], α- and β-chitin were hydrolyzed with concentrated hydrochloric acid at 40 °C. The reactant was mixed with acetone to recover the acetone-insoluble material, and (GlcNAc)4-6 was efficiently recovered after subsequent water extraction. Composition analysis using gel permeation chromatography and MALDI-TOF mass spectrometry indicated that (GlcNAc)4-6 could be isolated from the acetone-insoluble material with recoveries of approximately 17% and 21% from the starting α-chitin and β-chitin, respectively. The acetone precipitation method is highly useful for recovering chitin oligomers from the acid hydrolysate of chitin. The changes in the molecular size and higher-order structure of chitin during the course of hydrolysis were also analyzed, and a model that explains the process of oligomer accumulation is proposed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Research on the technical requirements standards of high efficiency precipitator in power industries for assessment

    Science.gov (United States)

    Jin, Huang; Ling, Lin; Jun, Guo; Jianguo, Li; Yongzhong, Wang

    2017-11-01

    Facing the increasingly severe situation of air pollution, China are now positively promoting the evaluation of high efficiency air pollution control equipments and the research of the relative national standards. This paper showed the significance and the effect of formulating the technical requirements of high efficiency precipitator equipments for assessment national standards in power industries as well as the research thoughts and principle of these standards. It introduce the qualitative and quantitative evaluation requirements of high efficiency precipitators using in power industries and the core technical content such as testing, calculating, evaluation methods and so on. The implementation of a series of national standards is in order to lead and promote the production and application of high efficiency precipitator equipments in the field of the prevention of air pollution in national power industries.

  16. [Low molecular weight carboxylic acids in precipitation during the rainy season in the rural area of Anshun, West Guizhou Province].

    Science.gov (United States)

    Zhang, Yan-Lin; Lee, Xin-Qing; Huang, Dai-Kuan; Huang, Rong-Sheng; Jiang, Wei

    2009-03-15

    40 rainwater samples were collected at Anshun from June 2007 to October 2007 and analysed in terms of pH values, electrical conductivity, major inorganic anions and soluble low molecular weight carboxylic acids. The results showed that pH of individual precipitation events ranged from 3.57-7.09 and the volume weight mean pH value was 4.57. The most abundant carboxylic acids were acetic (volume weight mean concentration 6.75 micromol x L(-1)) and formic (4.61 micromol x L(-1)) followed by oxalic (2.05 micromol x L(-1)). The concentration levels for these three species during summer especially June and July were comparatively high; it implied that organic acids in Anshun may came primarily from emissions from growing vegetations or products of the photochemical reactions of unsaturated hydrocarbons. Carboxylic acids were estimated to account for 32.2% to the free acidity in precipitation. The contribution was higher than in Guiyang rainwater, which indicated contamination by industry in Guiyang was more than in Anshun. The remarkable correlation(p = 0.01) between formic acid and acetic acid suggest that they have similar sources or similar intensity but different sources. And the remarkable correlation (p = 0.01) between and formic acid and oxalic acid showed that the precursors of oxalic acid and formic acid had similar sources. During this period, the overall wet deposition of carboxylic acids were 2.10 mmol/m2. And it appeared mainly in the summer, during which both concentration and contribution to free acidity were also relatively high. Consequently, it was necessary to control emission of organic acids in the summer to reduce frequence of acid rain in Anshun.

  17. Enantioselective Precipitate of Amines, Amino Alcohols, and Amino Acids via Schiff Base Reaction in the Presence of Chiral Ionic Liquid.

    Science.gov (United States)

    Wu, Datong; Cai, Pengfei; Zhao, Xiaoyong; Pan, Yuanjiang

    2017-10-06

    Two novel chiral ionic liquids are synthesized as the chiral selector. Racemates of amines, amino alcohols, and amino acids could generate enantioselective precipitate with multicomponent self-assemblies under mild conditions. The approach allows for enantioseparation with good yields (79-94%) and excellent ee's (>95%).

  18. Uncertainty Precipitation Assessment in a Hydrological Model at the Combeima River Basin, Colombia

    Science.gov (United States)

    Salgado, F., II

    2015-12-01

    Prediction and simulation of hydroclimatological events such as rain, have become an Absolute necessity in the management processes of watershed systems, particularly as it relates to the assessment of water resources and risk management. Precipitation is considered as a trigger to natural phenomena such as landslides, avalanches and floods, which occur as a result of the nonlinear interaction of hydrological dynamics. For the study and analysis of precipitation there are technological tools such as hydrological modeling, characterized by the transformation of input variables, such as precipitation and evapotranspiration rate. Therefore, precipitation is one of the most important variables because the quality and distribution of water resources depends upon it, thus a better understanding of the uncertainties associated with it is required. The precipitation in the tropics has a high variability at all spatial scales, from the microscale to the synoptic scale, as happens in the time scale (Poveda and Mejia 2004; Zawadzki, 1973). This space-time variability has implications for the modeling and simulation of storms, and in extreme flows. This fact, coupled with the hydrological models are calibrated setting, usually simulated flow against the flow observed using the recorded rainfall, which generates uncertainties. The main goal of this work was evaluate the uncertainty associated with the precipitation variable performing multiple simulations of synthetic events both in space and time, using the distributed hydrological model TETIS (Velez et al, 2002; Frances et al, 2007). A case study at the Watershed Andean high of Combeima River, in the city of Ibague (Colombia), was used to assess the uncertainty associated with the daily scale simulations.

  19. Phosphate recovery through struvite-family crystals precipitated in the presence of citric acid: mineralogical phase and morphology evaluation.

    Science.gov (United States)

    Perwitasari, D S; Edahwati, L; Sutiyono, S; Muryanto, S; Jamari, J; Bayuseno, A P

    2017-11-01

    Precipitation strategy of struvite-family crystals is presented in this paper to recover phosphate and potassium from a synthetic wastewater in the presence of citric acid at elevated temperature. The crystal-forming solutions were prepared from crystals of MgCl2 and NH4H2PO4 with a molar ratio of 1:1:1 for Mg(+2), [Formula: see text], and [Formula: see text], and the citric acid (C6H8O7) was prepared (1.00 and 20.00 ppm) from citric acid crystals. The Rietveld analysis of X-ray powder diffraction pattern confirmed a mixed product of struvite, struvite-(K), and newberyite crystallized at 30°C in the absence of citric acid. In the presence of citric acid at 30° and 40°C, an abundance of struvite and struvite-(K) were observed. A minute impurity of sylvite and potassium peroxide was unexpectedly found in certain precipitates. The crystal solids have irregular flake-shaped morphology, as shown by scanning electron microscopy micrograph. All parameters (citric acid, temperature, pH, Mg/P, and N/P) were deliberately arranged to control struvite-family crystals precipitation.

  20. Assessment of Hydrologic Response to Variable Precipitation Forcing: Russian River Case Study

    Science.gov (United States)

    Cifelli, R.; Hsu, C.; Johnson, L. E.

    2014-12-01

    NOAA Hydrometeorology Testbed (HMT) activities in California have involved deployment of advanced sensor networks to better track atmospheric river (AR) dynamics and inland penetration of high water vapor air masses. Numerical weather prediction models and decision support tools have been developed to provide forecasters a better basis for forecasting heavy precipitation and consequent flooding. The HMT also involves a joint project with California Department of Water Resources (CA-DWR) and the Scripps Institute for Oceanography (SIO) as part of CA-DWR's Enhanced Flood Response and Emergency Preparedness (EFREP) program. The HMT activities have included development and calibration of a distributed hydrologic model, the NWS Office of Hydrologic Development's (OHD) Research Distributed Hydrologic Model (RDHM), to prototype the distributed approach for flood and other water resources applications. HMT has applied RDHM to the Russian-Napa watersheds for research assessment of gap-filling weather radars for precipitation and hydrologic forecasting and for establishing a prototype to inform both the NWS Monterey Forecast Office and the California Nevada River Forecast Center (CNRFC) of RDHM capabilities. In this presentation, a variety of precipitation forcings generated with and without gap filling radar and rain gauge data are used as input to RDHM to assess the hydrologic response for selected case study events. Both the precipitation forcing and hydrologic model are run at different spatial and temporal resolution in order to examine the sensitivity of runoff to the precipitation inputs. Based on the timing of the events and the variations of spatial and temporal resolution, the parameters which dominate the hydrologic response are identified. The assessment is implemented at two USGS stations (Ukiah near Russian River and Austin Creek near Cazadero) that are minimally influenced by managed flows and objective evaluation can thus be derived. The results are assessed

  1. Recovery of Vanadium from H2SO4-HF Acidic Leaching Solution of Black Shale by Solvent Extraction and Precipitation

    Directory of Open Access Journals (Sweden)

    Xingbin Li

    2016-03-01

    Full Text Available The recovery of vanadium from sulfuric and hydrofluoric mixed acid solutions generated by the direct leaching of black shale was investigated using solvent extraction and precipitation methods. The process consisted of reduction, solvent extraction, and stripping, followed by precipitation and calcination to yield vanadium pentoxide. The influence of various operating parameters on the extraction and recovery of vanadium was studied. Vanadium (IV was selectively extracted using a mixture of 10% (v/v di(2-ethylhexylphosphoric acid and 5% (v/v tri-n-butylphosphate in sulfonated kerosene. Using six extraction and five stripping stages, the extraction efficiency for vanadium was 96.7% and the stripping efficiency was 99.7%. V2O5 with a purity of 99.52% was obtained by oxidation of the loaded strip solution and precipitation of ammonium polyvanadate at pH 1.8 to 2.2, followed by calcination of the dried precipitate at 550 °C for 2 h. It was concluded that the combination of solvent extraction and precipitation is an efficient method for the recovery of vanadium from a multi-element leach solution generated from black shale.

  2. Hydrological evaluation of precipitation intensity-duration thresholds for regional landslide hazard assessment

    Science.gov (United States)

    Bogaard, Thom; Greco, Roberto

    2017-04-01

    The vast majority of shallow landslides and debris flows are precipitation initiated. Therefore, regional landslide hazard assessment is often based on empirically derived precipitation-intensity-duration (PID) thresholds and landslide inventories. Generally, two features of precipitation events are plotted and labelled with (shallow) landslide occurrence or non-occurrence. Hereafter, a separation line or zone is drawn, mostly in logarithmic space. The practical background of PID is that often only meteorological information is available when analyzing (non-) occurrence of shallow landslides and, at the same time, the conceptual idea is that precipitation information is a good proxy for both meteorological trigger and hydrological cause. Although applied in many case studies, this approach suffers from indistinct threshold, many false positives as well as limited physical process understanding. Some first steps towards a more hydrologically based approach have been proposed in the past, but these efforts received limited follow-up. Therefore, the objective of our paper is to: a) critically analyse the concept of PID thresholds for shallow landslides and debris flows from a hydro-meteorological point of view, and b) propose a novel trigger-cause conceptual framework for lumped regional hydro-meteorological hazard assessment. We will discuss this based on the numerous (published) examples and associated discussion. We discuss the PID thresholds in relation to return periods of precipitation, soil physics and slope and catchment water balance. With this paper, we aim to contribute to the development of a stronger conceptual model for regional landslide hazard assessment based on physical process understanding and empirical data

  3. On the Relation between Natural and Enforced Syneresis of Acidic Precipitated Silica

    Directory of Open Access Journals (Sweden)

    Sebastian Wilhelm

    2014-11-01

    Full Text Available Silica in industrial production processes is precipitated by mixing an acid and an inorganic precursor. In this aqueous solution, silica particles form due to a polymerization reaction and agglomeration and, finally, build a gel. Thereafter, the reaction continues, and the gel network shrinks with the expulsion of the enclosed pore liquid. This slow process is known as “natural syneresis” and strongly affects the product properties, such as the agglomerate size, specific surface or porosity of the silica produced. In order to investigate the influence of process parameters, such as temperature, pH or ionic strength, on the shrinkage in shorter time-scales, we propose an acceleration of this process and define it as “enforced syneresis”. The acceleration is performed by applying a mechanical external force to the gel by means of a plunger and measuring the shrinkage behavior under these conditions. Thereby, the conceptual idea is the prediction of the shrinkage due to natural syneresis based on the results of enforced syneresis. We are now able to predict the natural syneresis behavior from enforced syneresis data by the development of a correlative model. Using this prediction model, we can show the influence of temperature on the maximum shrinkage and on its rate in a significantly shorter time of about 12 h instead of several days.

  4. Geological and hydrochemical sensitivity of the eastern United States to acid precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Hendrey, G.R.; Galloway, J.N.; Norton, S.A.; Schofield, C.L.; Shaffer, P.W.; Burns, D.A.

    1980-03-01

    A new analysis of bedrock geology maps of the eastern US constitutes a simple model for predicting areas which might be impacted by acid precipitation and it allows much greater resolution for detecting sensitivity than has previously been available for the region. Map accuracy has been verified by examining current alkalinities and pH's of waters in several test states, including Maine, New Hampshire, New York, Virginia and North Carolina. In regions predicted to be highly sensitive, alkalinities in upstream sites were generally low. Many areas of the eastern US are pinpointed in which some of the surface waters, especially upstream reaches, may be sensitive to acidification. Pre-1970 data were compared to post-1975 data, revealing marked declines in both alkalinity and pH of sensitive waters of two states tested, North Carolina, where pH and alkalinity have decreased in 80% of 38 streams and New Hampshire, where pH in 90% of 49 streams and lakes has decreased since 1949. These sites are predicted to be sensitive by the geological map on the basis of their earlier alkalinity values. The map is to be improved by the addition of a soils component.

  5. Selective recovery of soil-borne metal contaminants through integrated solubilization by biogenic sulfuric acid and precipitation by biogenic sulfide.

    Science.gov (United States)

    Fang, Di; Zhang, Ruichang; Liu, Xue; Zhou, Lixiang

    2012-06-15

    A hybrid process combining solubilization via sulfuric acid produced by sulfur-oxidizing bacteria with precipitation via sulfide produced by sulfate-reducing bacteria was investigated to isolate soil-borne metal contaminants as purified metal-sulfides. The highly efficient two-step acidification process involved bioproduction of sulfuric acid in a culture medium containing 30% (v/v) of sludge filtrate (SF). Soil was added to the culture after maximum acid production. Solubilization efficiencies of 95% for Zn, 76% for Cu and 97% for Cd were achieved after 16 days. At pH 1.9, 3.0 and 4.0, 99% of Cu(2+), 96% of Cd(3+) and 93% of Zn(2+), respectively, were precipitated from the soil leachate by sulfide transported from sulfidogenic bioreactor via N(2) sparging, resulting in final effluent metal contents at the ppb-level. The introduction of SF did not affect the precipitation kinetics and purity of the recovered precipitates. Ultimately, 75% of Cu and 86% of Zn were recovered from the soil as pure CuS and ZnS (confirmed by SEM-EDS and XRD). These results demonstrate the potential of the integrated method for the selective production of valuable metals from metal contamination in soils. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Assessment of precipitation and temperature data from CMIP3 global climate models for hydrologic simulation

    Science.gov (United States)

    McMahon, T. A.; Peel, M. C.; Karoly, D. J.

    2015-01-01

    The objective of this paper is to identify better performing Coupled Model Intercomparison Project phase 3 (CMIP3) global climate models (GCMs) that reproduce grid-scale climatological statistics of observed precipitation and temperature for input to hydrologic simulation over global land regions. Current assessments are aimed mainly at examining the performance of GCMs from a climatology perspective and not from a hydrology standpoint. The performance of each GCM in reproducing the precipitation and temperature statistics was ranked and better performing GCMs identified for later analyses. Observed global land surface precipitation and temperature data were drawn from the Climatic Research Unit (CRU) 3.10 gridded data set and re-sampled to the resolution of each GCM for comparison. Observed and GCM-based estimates of mean and standard deviation of annual precipitation, mean annual temperature, mean monthly precipitation and temperature and Köppen-Geiger climate type were compared. The main metrics for assessing GCM performance were the Nash-Sutcliffe efficiency (NSE) index and root mean square error (RMSE) between modelled and observed long-term statistics. This information combined with a literature review of the performance of the CMIP3 models identified the following better performing GCMs from a hydrologic perspective: HadCM3 (Hadley Centre for Climate Prediction and Research), MIROCm (Model for Interdisciplinary Research on Climate) (Center for Climate System Research (The University of Tokyo), National Institute for Environmental Studies, and Frontier Research Center for Global Change), MIUB (Meteorological Institute of the University of Bonn, Meteorological Research Institute of KMA, and Model and Data group), MPI (Max Planck Institute for Meteorology) and MRI (Japan Meteorological Research Institute). The future response of these GCMs was found to be representative of the 44 GCM ensemble members which confirms that the selected GCMs are reasonably

  7. The assessment of Global Precipitation Measurement estimates over the Indian subcontinent

    Science.gov (United States)

    Murali Krishna, U. V.; Das, Subrata Kumar; Deshpande, Sachin M.; Doiphode, S. L.; Pandithurai, G.

    2017-08-01

    Accurate and real-time precipitation estimation is a challenging task for current and future spaceborne measurements, which is essential to understand the global hydrological cycle. Recently, the Global Precipitation Measurement (GPM) satellites were launched as a next-generation rainfall mission for observing the global precipitation characteristics. The purpose of the GPM is to enhance the spatiotemporal resolution of global precipitation. The main objective of the present study is to assess the rainfall products from the GPM, especially the Integrated Multi-satellitE Retrievals for the GPM (IMERG) data by comparing with the ground-based observations. The multitemporal scale evaluations of rainfall involving subdaily, diurnal, monthly, and seasonal scales were performed over the Indian subcontinent. The comparison shows that the IMERG performed better than the Tropical Rainfall Measuring Mission (TRMM)-3B42, although both rainfall products underestimated the observed rainfall compared to the ground-based measurements. The analyses also reveal that the TRMM-3B42 and IMERG data sets are able to represent the large-scale monsoon rainfall spatial features but are having region-specific biases. The IMERG shows significant improvement in low rainfall estimates compared to the TRMM-3B42 for selected regions. In the spatial distribution, the IMERG shows higher rain rates compared to the TRMM-3B42, due to its enhanced spatial and temporal resolutions. Apart from this, the characteristics of raindrop size distribution (DSD) obtained from the GPM mission dual-frequency precipitation radar is assessed over the complex mountain terrain site in the Western Ghats, India, using the DSD measured by a Joss-Waldvogel disdrometer.

  8. Survival of Listeria innocua in rainbow trout protein recovered by isoelectric solubilization and precipitation with acetic and citric acids.

    Science.gov (United States)

    Otto, R A; Paker, I; Bane, L; Beamer, S; Jaczynski, J; Matak, K E

    2011-08-01

    During mechanical fish processing, a substantial amount of protein is discarded as by-products. Isoelectric solubilization and precipitation (ISP) is a process that uses extreme pH shifts to solubilize and precipitate protein from by-products to recover previously discarded protein. Typically, strong acids are used for pH reduction, but these acids do not have a pasteurization effect (6 log reduction) on bacterial load; therefore, organic acids were used during ISP processing to test the impact on Listeria innocua concentrations. Headed and gutted rainbow trout (Oncorhynchus mykiss) were inoculated with L. innocua, homogenized, and brought to the target pH with granular citric acid (pH 2.0 and 2.5) or glacial acetic acid (pH 3.0 and 3.5). Proteins were solubilized for 10 min at 4°C, and insoluble components (e.g., skin and insoluble protein) were removed by centrifugation. The remaining solution was pH shifted to the protein isoelectric point (pH 5.5) with sodium hydroxide, and precipitated protein was separated from the water. Microbial cells for each component (proteins, insolubles, and water) were enumerated on modified Oxford agar (MOX) and tryptic soy agar with 6% yeast extract (TSAYE). The sums of the surviving cells from each component were compared with the initial inoculum levels. No significant differences were observed between results obtained from TSAYE and from MOX (P > 0.05). Significant reductions in microbial populations were detected, regardless of pH or acid type (P acid, resulting in a mean reduction of 6.41 log CFU/g in the recovered protein and 5.88 log CFU/g in the combined components. These results demonstrate the antimicrobial potential of organic acids in ISP processing.

  9. Assessing trends in temperature, precipitation and streamflow due to climate change in Credit River watershed

    Energy Technology Data Exchange (ETDEWEB)

    Singh, A.; Dougherty, J.; Zimmer, C.; Kinkead, J.; Hulley, M.; Doherty, C. [Credit Valley Conservation Authority, Ontario (Canada)

    2009-07-01

    'Full text:' Studies on climate change at Natural Resources Canada showed that average temperature in Canada increased by 0.9°C since 1948 and further estimated that Ontario will warm by an average of 2°C to 5°C within the next 75 to 100 years. The climate change is linked to the anthropogenic activities which are understood to increasing green house gasses concentrations in the Earth's atmosphere thereby warming the planet. The warming is further related to affecting the components of hydrological cycle such as precipitation intensities, durations, snowfall, streamflow peaks, low flows etc. According to the Intergovernmental Panel on Climate Change (IPCC) Technical Paper on Climate Change and Water “Observational records and climate projections provide abundant evidence that freshwater resources are vulnerable and have the potential to be strongly impacted by climate change, with wide-ranging consequences for human societies and ecosystems.” The Ministry of Natural Resources projected temperature and precipitation changes for Southern Ontario for period 2075-2100 indicate 3-5°C higher summer and 5-6°C higher winter temperatures and ±10% change in annual precipitation from 1971-2000 using higher green house gas emission scenario (A2). However, the changes in climate and their effect on hydrological cycle could differ locally and these effects could be assessed using local historical data. Therefore, the Valley Conservation Authority initiated a study to assess how the climate change has affected the Credit River watershed by investigating trends in the historical temperature, precipitation and streamflow data sets. The temperature trends were analysed for mean, maximum and minimum temperatures on annual and monthly basis from nine meteorological stations located within or close to the Credit River watershed. The precipitation data from the same nine meteorological stations were used to analyse a) Intensity-Duration-Frequency (IDF) patterns

  10. Protein-poly(amino acid) precipitation stabilizes a therapeutic protein l-asparaginase against physicochemical stress.

    Science.gov (United States)

    Maruyama, Takuya; Izaki, Shunsuke; Kurinomaru, Takaaki; Handa, Kenji; Kimoto, Tomoaki; Shiraki, Kentaro

    2015-12-01

    Long-term storage in aqueous solution has been demanded for the practical application of therapeutic proteins. Recently, a precipitation-redissolution method was proposed to prepare salt-dissociable protein-polyelectrolyte complex (PPC). To elucidate the utility of the complex for storage of proteins, we investigated the stress tolerance of PPC precipitates containing l-asparaginase (ASNase) and poly-l-lysine (polyK). PPC precipitate containing ASNase and polyK was prepared by precipitation-redissolution method. The sample was treated to three types of stress, i.e., heat, shaking, and oxidation. The protein concentration, enzyme activity, and CD spectrum of the supernatants of samples were measured after stressed. PPC precipitate consisting of ASNase and polyK showed tolerance against thermal and shaking stress compared to the native solution. In addition, PPC precipitate protected ASNase from inactivation by oxidation. PPC precipitate of ASNase/polyK complex successfully stabilized ASNase against physicochemical stresses. These results suggest that the PPC precipitate has great potential as a storage method in aqueous solution for unstable proteins. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  11. The Effect of Double Crosslinker on Precipitation Polymerization of Poly(acrylic acid

    Directory of Open Access Journals (Sweden)

    Hajar Es-haghi

    2014-06-01

    Full Text Available Cross-linked poly(acrylic acids were prepared by dual cross-linkers via precipitation polymerization method in a binary organic solvent. Polyethylene glycol diacrylate (PEGDA-400 as a long-chain cross-linker and di(trimethylol propane tetraacrylate (DTMPTA as multifunctional cross-linker were used. PEGDA-400 was utilized to increase thickening properties and DTMPTA was used to improve the gel strength. The dual cross-linkers effect on the sample features (i.e., equilibrium swelling, thickening properties and rheological properties was investigated. Maximum amount of swelling was obtained by a high percentage of long-chain cross-linker. The apparent viscosity of the microgels was measured to determine their thickening properties for aqueous media. Maximum viscosity occurred at DT25-PE75 which was dependent on the type of cross-linkers in the polymer structure. The Flory-Rehner equation (from swelling ratio data and rubber elasticity theory (from rheometry data were used to discuss the network structure of the polymer. Increasing density of the network was shown by a sample containing high percentage of a four-functional cross-linker. The rheological properties of the cross-linked polymers were measured to determine storage modulus (strength network. The rheological behaviors demonstrated that the synthesized polymer containing a high amount of four-functional cross-linker had higher storage modulus (G′ than other samples. In addition the consistency coefficient (m and flow behavior index (n parameters of Ostwald equation were investigated as well. As a result, n values in each sample were found to be smaller than 1 and these results were fitted clearly with the pseudoplastic model. Apparent and rotational viscosities were used to determine the optimal cross-linker type (synthesized sample contained a high percentage of long-chain cross-linker.

  12. Assessment of {sup 7}Be content in precipitation in a South American semi-arid environment

    Energy Technology Data Exchange (ETDEWEB)

    Juri Ayub, J., E-mail: jjuri@unsl.edu.ar [Grupo de Estudios Ambientales, Instituto de Matematica Aplicada San Luis, Universidad Nacional de San Luis/CCT-San Luis-CONICET, San Luis (Argentina); LARA, Laboratorio de Radioecologia, Instituto de Fisica, Universidade Federal Fluminense, Niteroi, RJ (Brazil); Lohaiza, F.; Velasco, H.; Rizzotto, M. [Grupo de Estudios Ambientales, Instituto de Matematica Aplicada San Luis, Universidad Nacional de San Luis/CCT-San Luis-CONICET, San Luis (Argentina); Di Gregorio, D.; Huck, H. [Departamento de Fisica, Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin, Buenos Aires (Argentina)

    2012-12-15

    -Right-Pointing-Pointer {sup 7}Be in precipitation was measured at a semiarid location in central Argentina. Black-Right-Pointing-Pointer No atmospheric washout was observed except for one high precipitation event. Black-Right-Pointing-Pointer Wet deposition of {sup 7}Be was linearly correlated with precipitation. Black-Right-Pointing-Pointer This relationship may be applied as a tool for assessing environmental processes. Black-Right-Pointing-Pointer The latter includes natural processes as well as the impacts of human disturbance.

  13. Removal of Trace Levels of Cu(II) from Seawater by Co-precipitation with Humic Acids.

    Science.gov (United States)

    Iwai, Hisanori

    2017-01-01

    To maintain performance related to fuel consumption and maneuverability, the bottom of ships are painted with antifouling paint that contains Cu2O as a biocidal pigment. However, in enclosed coastal areas around dockyards, some of the Cu(II) contained in the paint is eluted into the surrounding water. The present study examined the removal of Cu from seawater by co-precipitation with humic acids (HAs). After precipitating the HA in seawater, the amount of Cu(II) in the supernatant was colorimetrically measured by a colorimetry using bathocuproine. The removal efficiency (RE%) for micromolar Cu(II) increased with increasing initial concentrations of HAs. An RE of 90% was obtained using an HA derived from hardwood bark compost. Aromatic components in the HA that contained highly substituted acidic functional groups appeared to enhance the removal of Cu(II). The findings reported herein indicate that HAs represent a useful material for removing trace levels of Cu from seawater.

  14. Molecularly imprinted polymer for caffeic acid by precipitation polymerization and its application to extraction of caffeic acid and chlorogenic acid from Eucommia ulmodies leaves.

    Science.gov (United States)

    Miura, Chitose; Matsunaga, Hisami; Haginaka, Jun

    2016-08-05

    Molecularly imprinted polymers (MIPs) for caffeic acid (CA) were prepared using 4-vinylpyridine and methacrylamide (MAM) as functional monomers, divinylbenzene as a crosslinker and acetonitrile-toluene (3:1, v/v) as a porogen by precipitation polymerization. The use of MAM as the co-monomer resulted in the formation of microsphere MIPs and non-imprinted polymers (NIPs) with ca. 3- and 5-μm particle diameters, respectively. Binding experiments and Scatchard analyses revealed that the binding capacity and affinity of the MIP to CA are higher than those of the NIP. The retention and molecular-recognition properties of the prepared MIPs were evaluated using water-acetonitrile and sodium phosphate buffer-acetonitrile as mobile phases in hydrophilic interaction chromatography (HILIC) and reversed-phase chromatography, respectively. In HILIC mode, the MIP showed higher molecular-recognition ability for CA than in reversed-phase mode. In addition to shape recognition, hydrophilic interactions seem to work for the recognition of CA on the MIP in HILIC mode, while hydrogen bonding and hydrophobic interactions seem to work for the recognition of CA in reversed-phase mode. The MIP had a specific molecular-recognition ability for CA in HILIC mode, while other structurally related compounds, such as chlorogenic acid (CGA), gallic acid, protocatechuic acid and vanillic acid, could not be recognized by the MIP. Furthermore, the MIP was successfully applied for extraction of CA and CGA in the leaves of Eucommia ulmodies in HILIC mode. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. 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.

  16. 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.

  17. A procedure for assessing future trends of subdaily precipitation values on point scale

    Science.gov (United States)

    Rianna, Guido; Villani, Veronica; Mercogliano, Paola; Vezzoli, Renata

    2015-04-01

    In many areas of Italy, urban flooding or floods in small mountain basins, induced by heavy precipitations on subdaily scale, represent remarkable hazards able to cause huge damages and casualties often increased by very high population density. A proper assessment about how frequency and magnitude of such events could change under the effect of Climate Changes (CC) is crucial for the development of future territorial planning (such as early warning systems). The current constraints of climate modeling, also using high resolution RCM, prevent an adequate representation of subdaily precipitation patterns (mainly concerning extreme values) while available observed datasets are often unsuitable for the application of the bias-correction (BC) techniques requiring long time series. In this work, a new procedure is proposed: at point scale, precipitation outputs on 24 and 48 hours are provided by high resolution (about 8km) climate simulation performed through the RCM COSMO_CLM driven by GCM CMCC_CM and bias-corrected by quantile mapping approach. These ones are adopted for a monthly stochastic disaggregation approach combining Random Parameter Bartlett-Lewis (RPBL) gamma model with appropriate rainfall disaggregation technique. The last one implements empirical correction procedures, called adjusting procedures, to modify the model rainfall output, so that it is consistent with the observed rainfall values on daily time scale. In order to take into account the great difficulties related to minimization of objective function required by retrieving the 7 RPBL parameters, for each dataset the computations are repeated twenty times. Moreover, adopting statistical properties on 24 and 48 hours to retrieve RPBL parameters allows, according Bo et al. (1994), to infer statistical properties until hourly scale maintaining the information content about the possible changes in precipitation patterns due to CC. The entire simulation chain is tested on Baiso weather station, in

  18. Assessment of CORDEX-SA experiments in representing precipitation climatology of summer monsoon over India

    Science.gov (United States)

    Choudhary, A.; Dimri, A. P.; Maharana, P.

    2017-09-01

    The present work assesses the performance of 11 regional climate simulations in representing the precipitation patterns of summer monsoon over India for the period 1970-2005. These simulations have been carried out under Coordinated Regional Climate Downscaling Experiment-South Asia (CORDEX-SA) project. The regional climate models (RCMs) have been inter-compared as well as evaluated against the observation to identify the common weaknesses and differences between them. For this, a number of statistical analysis has been carried out to compare the model precipitation field with the corresponding observation. Model uncertainty has been also evaluated through bias studies and analysis of the spread in the ensemble mean (hereafter, ensemble). The models which perform better than the rest are identified and studied to look for any improvement in the ensemble performance. These better performing experiments (best RCM experiments) are further assessed over the monsoon core region (MCR) of India. This has been done to understand how well the models perform in a spatially homogeneous zone of precipitation which is considered to be a representative region of Indian summer monsoon characteristics. Finally, an additional analysis has been done to quantify the skill of models based on two different metrics—performance and convergence including a combination of the two. The experiment with regional model RegCM4 forced with the global model GFDL-ESM2M shows the highest combined mean skill in capturing the seasonal mean precipitation. In general, a significant dry bias is found over a larger part of India in all the experiments which seems most pronounced over the central Indian region. Ensemble on an average tends to outperform many of the individual experiments with bias of smaller magnitude and an improved spatial correlation compared with the observation. Experiments which perform better over India improve the results but only slightly in terms of agreement among experiments

  19. Removal of chromophore in enzymatic hydrolysis by acid precipitation to improve the quality of xylo-oligosaccharides from corn stalk.

    Science.gov (United States)

    Wang, Yue-Hai; Zhang, Jie; Qu, Yong-Shui; Li, Hong-Qiang

    2017-08-16

    As the most representative functional sugar, the application areas and market demands of xylo-oligosaccharides (XOS) have been expanding year by year. Owing to the complex structure of corn stalk (CS), XOS obtained from CS are accompanied by problems such as low purity and high color value, which degrade the product. To improve the quality of XOS from CS, the enzymatic hydrolysis was precipitated by acid; then, the ethanol elution concentration was systematically investigated after optimizing the adsorption conditions. The results showed that the purity of XOS was increased to 87.28% from 67.31%, and the color value was decreased to 1050 from 4682 when the acid precipitation pH was 2. On the basis of acid precipitation, if the corresponding optimal conditions of XOS adsorption and elution were used, the highest purity of XOS was 97.87% obtained, with the lowest color value, 780, which reached the standard of the commercial XOS. Copyright © 2017. Published by Elsevier Ltd.

  20. Production of a poly-alumino-iron sulphate coagulant by chemical precipitation of a coal mining acid drainage

    Energy Technology Data Exchange (ETDEWEB)

    Menezes, J.C.S.S.; Silva, R.A.; Arce, I.S.; Schneider, I.A.H. [Universidade Federal do Rio Grande do Sul, Porto Alegre (Brazil)

    2010-02-15

    The aim of this work was to produce a poly-alumino-iron sulphate coagulant from acidic coal mine drainage. Precipitating the iron and aluminium at pH 5.0, followed by dissolution in sulphuric acid, produced a coagulant consisting of 8.7% iron and 3.3% aluminium. Water treatment tests proved that this coagulant was as efficient as the coagulant chemicals conventionally used in water treatment plants. The process can be easily incorporated into conventional AMD treatment plants, thereby reducing sludge waste issues and producing a valuable chemical reagent.

  1. Amino acid, fatty acid, and mineral profiles of materials recovered from rainbow trout (Oncorhynchus mykiss) processing by-products using isoelectric solubilization/precipitation.

    Science.gov (United States)

    Chen, Y-C; Tou, J C; Jaczynski, J

    2007-11-01

    Protein, lipid, and insolubles (bones, skin, scales, fins, insoluble protein, and more) were recovered from rainbow trout processing by-products by means of isoelectric solubilization/precipitation at basic pH and acidic pH. Isoelectric solubilization/precipitation of the trout processing by-products resulted in the recovery of protein that was higher (P acids (EAAs), non-EAAs, and total EAA/total AA ratio when compared to the processing by-products. Basic pH treatments yielded a higher (P acidic pH treatments. Nutritional quality of the recovered protein was high based on EAAs meeting the FAO/WHO/UNU recommendations for adults. The presence of omega-3 and omega-6 fatty acids (omega-3, omega-6 FAs) and the omega-3/omega-6 ratio in the recovered lipids were similar to the trout processing by-products, indicating that the pH treatments had no effect on these FAs. Ca and P contents of the processing by-products exceeded the recommended dietary allowances (RDA), but Fe and Mg did not. Basic pH treatments yielded protein with the lowest (P acidic pH. The isoelectric solubilization/precipitation of the processing by-products effectively removed minerals from the recovered protein without removal of the bones, skin, scales, fins, and so on, prior to processing. The results indicated that isoelectric solubilization/precipitation, particularly at basic pH, permitted recovery of high-quality protein and lipids from fish processing by-products for human food uses; also, the recovered insolubles may be used in animal feeds as a source of minerals.

  2. How to apply the dependence structure analysis to extreme temperature and precipitation for disaster risk assessment

    Science.gov (United States)

    Feng, Jieling; Li, Ning; Zhang, Zhengtao; Chen, Xi

    2017-06-01

    IPCC reports that a changing climate can affect the frequency and the intensity of extreme events. However, the extremes appear in the tail of the probability distribution. In order to know the relationship between extreme events in the tail of temperature and precipitation, an important but previously unobserved dependence structure is analyzed in this paper. Here, we examine the dependence structure by building a bivariate joint of Gumbel copula model for temperature and precipitation using monthly average temperature (T) and monthly precipitation (P) data from Beijing station in China covering a period of 1951-2015 and find the dependence structure can be divided into two sections, they are the middle part and the upper tail. We show that T and P have a strong positive correlation in the high tail section (T > 25.85 °C and P > 171.1 mm) (=0.66, p < 0.01) while they do not demonstrate the same relation in the other section, which suggests that the identification of a strong influence of T on extreme P needs help from the dependence structure analysis. We also find that in the high tail section, every 1 °C increase in T is associated with 73.45 mm increase in P. Our results suggested that extreme precipitation fluctuations by changes in temperature will allow the data dependence structure to be included in extreme affect for the disaster risk assessment under future climate change scenarios. Copula bivariate jointed probability distribution is useful to the dependence structure analysis.

  3. Lanthanide-alkali double sulfate precipitation from strong sulfuric acid NiMH battery waste leachate.

    Science.gov (United States)

    Porvali, Antti; Wilson, Benjamin P; Lundström, Mari

    2018-01-01

    In NiMH battery leaching, rare earth element (REE) precipitation from sulfate media is often reported as being a result of increasing pH of the pregnant leach solution (PLS). Here we demonstrate that this precipitation is a phenomenon that depends on both Na+ and SO42- concentrations and not solely on pH. A two-stage leaching for industrially crushed NiMH waste is performed: The first stage consists of H2SO4 leaching (2 M H2SO4, L/S = 10.4, V = 104 ml, T = 30 °C) and the second stage of H2O leaching (V = 100 ml, T = 25 °C). Moreover, precipitation experiments are separately performed as a function of added Na2SO4 and H2SO4. During the precipitation, higher than stoichiometric quantities of Na to REE are utilized and this increase in both precipitation reagent concentrations results in an improved double sulfate precipitation efficiency. The best REE precipitation efficiencies (98-99%) - achieved by increasing concentrations of H2SO4 and Na2SO4 by 1.59 M and 0.35 M, respectively - results in a 21.8 times Na (as Na2SO4) and 58.3 times SO4 change in stoichiometric ratio to REE. Results strongly indicate a straightforward approach for REE recovery from NiMH battery waste without the need to increase the pH of PLS. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Adsorption and co-precipitation behavior of arsenate, chromate, selenate and boric acid with synthetic allophane-like materials.

    Science.gov (United States)

    Opiso, Einstine; Sato, Tsutomu; Yoneda, Tetsuro

    2009-10-15

    Pollution caused by boric acid and toxic anions such as As(V), Cr(VI) and Se(VI) is hazardous to human health and environment. The sorption characteristics of these environmentally significant ionic species on allophane-like nanoparticles were investigated in order to determine whether allophane can reduce their mobility in the subsurface environment at circum-neutral pH condition. Solutions containing 100 or 150 mmol of AlCl(3)x6H(2)O were mixed to 100 mmol of Na(4)SiO(4) and the pH were adjusted to 6.4+/-0.3. The mineral suspensions were shaken for 1h and incubated at 80 degrees C for 5 days. Appropriate amounts of As, B, Cr and Se solutions were added separately during and after allophane precipitation. The results showed that As(V) and boric acid can be irreversibly fixed during co-precipitation in addition to surface adsorption. However, Cr(VI) and Se(VI) retention during and after allophane precipitation is mainly controlled by surface adsorption. The structurally fixed As(V) and boric acid were more resistant to release than those bound on the surface. The sorption characteristics of oxyanions and boric acid were also influenced by the final Si/Al molar ratio of allophane in which Al-rich allophane tend to have higher uptake capacity. The overall results of this study have demonstrated the role of allophane-like nanoparticles and the effect of its Si/Al ratio on As, B, Cr and Se transport processes in the subsurface environment.

  5. High resolution decadal precipitation predictions over the continental United States for impacts assessment

    Science.gov (United States)

    Salvi, Kaustubh; Villarini, Gabriele; Vecchi, Gabriel A.

    2017-10-01

    Unprecedented alterations in precipitation characteristics over the last century and especially in the last two decades have posed serious socio-economic problems to society in terms of hydro-meteorological extremes, in particular flooding and droughts. The origin of these alterations has its roots in changing climatic conditions; however, its threatening implications can only be dealt with through meticulous planning that is based on realistic and skillful decadal precipitation predictions (DPPs). Skillful DPPs represent a very challenging prospect because of the complexities associated with precipitation predictions. Because of the limited skill and coarse spatial resolution, the DPPs provided by General Circulation Models (GCMs) fail to be directly applicable for impact assessment. Here, we focus on nine GCMs and quantify the seasonally and regionally averaged skill in DPPs over the continental United States. We address the problems pertaining to the limited skill and resolution by applying linear and kernel regression-based statistical downscaling approaches. For both the approaches, statistical relationships established over the calibration period (1961-1990) are applied to the retrospective and near future decadal predictions by GCMs to obtain DPPs at ∼4 km resolution. The skill is quantified across different metrics that evaluate potential skill, biases, long-term statistical properties, and uncertainty. Both the statistical approaches show improvements with respect to the raw GCM data, particularly in terms of the long-term statistical properties and uncertainty, irrespective of lead time. The outcome of the study is monthly DPPs from nine GCMs with 4-km spatial resolution, which can be used as a key input for impacts assessments.

  6. Sub-micrometer-sized biodegradable particles of poly(L-lactic acid) via the gas antisolvent spray precipitation process.

    Science.gov (United States)

    Randolph, T W; Randolph, A D; Mebes, M; Yeung, S

    1993-01-01

    Sub-micrometer-sized particles of poly(L-lactic acid) may be formed by using near-critical or supercritical carbon dioxide as an antisolvent to precipitate poly(L-lactic acid) from droplets of methylene chloride solution sprayed into a carbon dioxide continuous phase. Particle sizes may be controlled by varying the density of the carbon dioxide; at constant temperature in the supercritical region, higher carbon dioxide densities yield larger particles. Two methods (one batch and one continuous) for introducing the poly(L-lactic acid) solutions into carbon dioxide are demonstrated. Although the two methods use very different mechanisms for forming the droplets, similar particle sizes are observed as a function of carbon dioxide density. We suggest that mass transport, rather than jet breakup and hydrodynamics, controls particle sizes in the near-critical and supercritical regions.

  7. Ammonia-Oxidizing Archaea Are More Resistant Than Denitrifiers to Seasonal Precipitation Changes in an Acidic Subtropical Forest Soil

    Directory of Open Access Journals (Sweden)

    Jie Chen

    2017-07-01

    Full Text Available Seasonal precipitation changes are increasingly severe in subtropical areas. However, the responses of soil nitrogen (N cycle and its associated functional microorganisms to such precipitation changes remain unclear. In this study, two projected precipitation patterns were manipulated: intensifying the dry-season drought (DD and extending the dry-season duration (ED but increasing the wet-season storms following the DD and ED treatment period. The effects of these two contrasting precipitation patterns on soil net N transformation rates and functional gene abundances were quantitatively assessed through a resistance index. Results showed that the resistance index of functional microbial abundance (-0.03 ± 0.08 was much lower than that of the net N transformation rate (0.55 ± 0.02 throughout the experiment, indicating that microbial abundance was more responsive to precipitation changes compared with the N transformation rate. Spring drought under the ED treatment significantly increased the abundances of both nitrifying (amoA and denitrifying genes (nirK, nirS, and nosZ, while changes in these gene abundances overlapped largely with control treatment during droughts in the dry season. Interestingly, the resistance index of the ammonia-oxidizing archaea (AOA amoA abundance was significantly higher than that of the denitrifying gene abundances, suggesting that AOA were more resistant to the precipitation changes. This was attributed to the stronger environmental adaptability and higher resource utilization efficiency of the AOA community, as indicated by the lack of correlations between AOA gene abundance and environmental factors [i.e., soil water content, ammonium (NH4+ and dissolved organic carbon concentrations] during the experiment.

  8. Carbonate precipitation under bulk acidic conditions as a potential biosignature for searching life on Mars

    NARCIS (Netherlands)

    Fernández-Remolar, David C.; Preston, Louisa J.; Sánchez-Román, Mónica; Izawa, Matthew R.M.; Huang, L.; Southam, Gordon; Banerjee, Neil R.; Osinski, Gordon R.; Flemming, Roberta; Gómez-Ortíz, David; Prieto-Ballesteros, Olga; Rodríguez, Nuria; Amils, Ricardo; Darby Dyar, M.

    2012-01-01

    Recent observations of carbonate minerals in ancient Martian rocks have been interpreted as evidence for the former presence of circumneutral solutions optimal for carbonate precipitation. Sampling from surface and subsurface regions of the low-pH system of Río Tinto has shown, unexpectedly, that

  9. The influence of calcium, magnesium, phosphorus and silica on vanadium precipitation in acidic sulfate solutions

    Directory of Open Access Journals (Sweden)

    A. H. Martins

    2000-06-01

    Full Text Available The experimental research work was carried out in accordance with the Factorial Design Statistical Method to evaluate and analyze the influence of calcium, magnesium, silica and phosphorus on the precipitation of vanadates. Precipitation was performed by neutralization with H2SO4 of alkaline aqueous solutions containing vanadium pentoxide (V2O5 at 60± 2ºC. The experimental responses measured were percent of vanadium recovery and vanadium pentoxide content in the precipitate. These impurities are considered representative of those present in a leach liquor from the ore obtained at Campo Alegre de Lourdes (Brazil. The operational variables in this work were used under optimum conditions as determined by the statistical approach. Among the impurities under study, phosphorus exhibited the highest negative influence on the experimental responses. Phosphorus diminished the percent of vanadium recovered from 98.9 to 34.5 and the vanadium oxide content in the precipitate from 91.2 % to 39.3 %.

  10. Precipitation regime for selected amino acid salts for CO2 capture from flue gases

    NARCIS (Netherlands)

    Majchrowicz, Magdalena E.; Brilman, Derk Willem Frederik; Groeneveld, M.J.

    2009-01-01

    The tendency of alkaline (sodium, potassium and lithium) salts of taurine, β-alanine, sarcosine and L-proline to form precipitates under varying operational conditions of CO2 absorption has been investigated. CO2 absorption experiments have been performed at 293.15 and 313.15 K, at partial pressures

  11. Evaluation of the Potential of NASA Multi-satellite Precipitation Analysis in Global Landslide Hazard Assessment

    Science.gov (United States)

    Hong, Yang; Adler, Robert F.; Huffman, George J.

    2007-01-01

    Landslides are one of the most widespread natural hazards on Earth, responsible for thousands of deaths and billions of dollars in property damage every year. In the U.S. alone landslides occur in every state, causing an estimated $2 billion in damage and 25- 50 deaths each year. Annual average loss of life from landslide hazards in Japan is 170. The situation is much worse in developing countries and remote mountainous regions due to lack of financial resources and inadequate disaster management ability. Recently, a landslide buried an entire village on the Philippines Island of Leyte on Feb 17,2006, with at least 1800 reported deaths and only 3 houses left standing of the original 300. Intense storms with high-intensity , long-duration rainfall have great potential to trigger rapidly moving landslides, resulting in casualties and property damage across the world. In recent years, through the availability of remotely sensed datasets, it has become possible to conduct global-scale landslide hazard assessment. This paper evaluates the potential of the real-time NASA TRMM-based Multi-satellite Precipitation Analysis (TMPA) system to advance our understanding of and predictive ability for rainfall-triggered landslides. Early results show that the landslide occurrences are closely associated with the spatial patterns and temporal distribution of rainfall characteristics. Particularly, the number of landslide occurrences and the relative importance of rainfall in triggering landslides rely on the influence of rainfall attributes [e.g. rainfall climatology, antecedent rainfall accumulation, and intensity-duration of rainstorms). TMPA precipitation data are available in both real-time and post-real-time versions, which are useful to assess the location and timing of rainfall-triggered landslide hazards by monitoring landslide-prone areas while receiving heavy rainfall. For the purpose of identifying rainfall-triggered landslides, an empirical global rainfall intensity

  12. 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.

  13. Compositional characteristics of materials recovered from headed gutted silver carp (Hypophthalmichthys molitrix) by isoelectric solubilization and precipitation using organic acids.

    Science.gov (United States)

    Paker, Ilgin; Beamer, Sarah; Jaczynski, Jacek; Matak, Kristen E

    2013-03-01

    Protein was recovered from headed gutted silver carp by isoelectric solubilization at pH 2.5, 3.0, 11.5, or 12.0 and precipitation (ISP) at pH 5.5 using acetic (AA) or a 30% formic and lactic acid combination (F&L) and 10 N sodium hydroxide. Total protein and fat recovery yields, proximate composition and mineral analyses of fractions were determined. Protein and lipid recovery yields when solubilized under basic conditions were comparable to yields reported from other studies using hydrochloric acid; however, the recovered fractions were less pure. Processing at basic pH using AA was more effective than F&L at removing impurities (P 0.05). For the most part, sodium was greater (P magnesium, and iron (P < 0.05) in the recovered protein regardless of acid used when compared to the initial paste. This research shows that organic acids have the potential to recover protein and lipid by ISP processing. This research presents a reliable method for extracting nutritionally valuable fish protein and oils from otherwise hard to process fish and its byproducts. Replacing the traditionally used strong acids with organic acids might further accomplish bacterial load reduction while resulting in similar to or improved protein recovery yields. Therefore, this technology may increase the commercial viability of hard to process fish. © 2013 Institute of Food Technologists®

  14. Effect of precipitation, geographical location and biosynthesis on New Zealand milk powder bulk and fatty acids D/H ratios

    Science.gov (United States)

    Frew, R.; Emad Ehtesham, R.; Van Hale, R.; Hayman, A.; Baisden, T.

    2012-04-01

    D/H ratio measurements provide useful information for the investigation of biogeochemical influences on natural and agricultural produce, particularly with application to food traceability and authentication. Numerous studies have shown that variation of a product's D/H ratio is influenced by both environmental factors and biological processes. This study investigates the D/H ratio of New Zealand milk powder and individual fatty acids, and causal determinants of isotopic variation. One of the key environmental factors is precipitation, and the D/H ratio "isoscaping" of NZ has been undertaken. New Zealand provides a unique geography for these kinds of study in terms of proximity to the ocean and natural geographical variability from sea level to elevations as high as 3700 m. Milk powder samples were collected from different geographical regions from milk processing units, which were supplied by producers in the immediate region. H/D ratios of bulk milk powder and of individual fatty acids were determined. Initial comparison of the precipitation and milk powder bulk D/H data show a very good differentiation from north to southernmost parts of New Zealand and a relation between rain and milk bulk D/H abundance ratio. Almost 98% of milk FAs are in the form of triglycerides that have been extracted and hydrolysed to free FAs. Free FAs were esterified and analyzed with GC-IRMS. Individual FAs show variation in D/H ratio, and all values are depleted relative to the precipitation data. The difference in D/H ratio amongst individual FAs reflects the geographical environment and biological processes i.e. micro-organisms activity in the rumen of the cow. Short chain FAs (less than 8 carbons), particularly C4 (Butyric acid), appear to be key determinants. The variation in the data can be rationalized using statistical multivariate analysis.

  15. Role of local heterogeneities on the localization of dissolution and precipitation reactions during acidic fluid percolation through different limestone samples

    Science.gov (United States)

    Luquot, Linda; Carrera, Jesus

    2017-04-01

    CO2 sequestration in deep geological formation is considered an option to reduce CO2 emissions in the atmosphere. After injection, the CO2 will slowly dissolve into the pore water producing low pH fluids with a high capacity for dissolving carbonates. Limestone rock dissolution induces geometrical parameters changes such as porosity, pore size distribution, or tortuosity which may consequently modify transport properties (permeability, diffusion coefficient). Characterizing these changes is essential for modelling flow and CO2 transport during and after the CO2 injection. Indeed, these changes can affect the storage capacity and injectivity of the formation. Very few published studies evaluate the transport properties changes (porosity, permeability, pore size distribution, diffusion coefficient) due to fluid-rock interactions (dissolution and/or precipitation). Here we report experimental results from the injection of acidic fluids (some of them equilibrated with gypsum) into limestone core samples of 25.4 mm diameter and around 25 mm length. We studied two different limestone samples: one composed of 73% of calcite and 27% of quartz, and the second one of 100% of dolomite. Experiments were realized at room temperature. Before and after each acidic rock attack, we measure the sample porosity, the diffusion coefficient and the pore size distribution. We also imaged the 3D pore network by X-ray microtomography to evaluate the same parameters. During percolation experiments, the permeability changes are recorded and chemical samples taken to evaluate calcite dissolution and gypsum precipitation. Several dissolution/precipitation-characterization cycles are performed on each sample in order to study the evolution and relation of the different parameters. These experiments show different dissolution regimes depending of the fluid acidity and of the limestone samples in particular the initial local heterogeneity, and pore size distribution.

  16. 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.

  17. Spatiotemporal distribution and source apportionment of low molecular weight organic acids in wet precipitation at a coastal city, China.

    Science.gov (United States)

    Du, Wenjiao; Hong, Zhenyu; Chen, Yanting; Deng, Junjun; Chen, Jinsheng; Xu, Lingling; Hong, Youwei; Xiao, Hang

    2017-03-01

    To investigate the characteristics and sources of low molecular weight (LMW) organic acids in wet precipitation at a coastal city, Xiamen, a total of 313 rainwater samples were collected at seven different functional areas from September 2012 to August 2013. Spatiotemporal characteristics of LMW organic acids as well as pH and electrical conductivity were analyzed. Meanwhile, air mass clusters in different seasons and the positive matrix factorization (PMF) source apportion model were comprehensively used to identify the sources of organic acids. In conclusion, the volume-weighted mean (VWM) concentration of formic (3.20 μmol/L), acetic (1.84 μmol/L), lactic (0.44 μmol/L), and oxalic acid (0.53 μmol/L) were obtained, which jointly contributed to 4.33% of the total free acidity (TFA). At the same time, the highest wet deposition flux of LMW organic acids and contribution of that to TFA were achieved at the forest protection area during growing season in Xiamen. In addition, biogenic emissions (77.12%), sea salts (13.77%), regional agriculture activities (3.92%), soil emissions (2.56%), biomass burning (1.47%), and secondary aerosols (1.15%) were determined as the source of LMW organic acids. Besides, the dominancy of biomass burning via long-range transport in non-growing season (NGS) and the contribution of biogenic emission in growing season (GS) were recognized. Finally, the considerable influence of sea salts on the LMW organic acids (13.77%) in Xiamen was quantified, especially for oxalic acid.

  18. Multi-element analysis of milk by ICP-oa-TOF-MS after precipitation of calcium and proteins by oxalic and nitric acid.

    Science.gov (United States)

    Husáková, Lenka; Urbanová, Iva; Šrámková, Jitka; Konečná, Michaela; Bohuslavová, Jana

    2013-03-15

    In this work a simple technique employing oxalic and nitric acid to cow's milk samples prior to analysis by inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometry (ICP-oa-TOF-MS) was introduced. After the precipitation of calcium and proteins via oxalic and nitric acid, respectively, the resulting liquid phase was aspirated with a concentric glass nebulizer for ICP-TOF-MS determination of trace elements. Precipitation of proteins is essential for better separation of solid and liquid phase of modified samples. Separation of calcium as a precipitated non-soluble oxalate enables the elimination of spectral interferences originating from different calcium containing species like (40)Ca(35)Cl(+), (40)Ca(37)Cl(+), (43)Ca(16)O(+), (40)Ca(18)O(+), (44)Ca(16)O(+), (43)Ca(16)O(1)H(+) onto the determination of As, Se, Co and Ni whose assay is more difficult when using conventional quadrupole instruments. High detection capability is further an advantage as the approach enables the analysis without dilution. The methodology may serve, in addition, for a fast and sensitive determination of some other elements. After that, direct, reliable and simultaneous determination of 16 elements (Li, Be, B, V, Cr, Mn, Ni, Co, Ga, As, Se, Mo, Sn, Sb, Cs, Tl) at trace and ultra-trace levels in milk can be performed under optimum instrumental conditions and by using Rh as an internal standard. Accuracy and precision was assessed by measuring NCS ZC73015 milk powder control standard, yielding results in agreement with certified values and RSD <10%. The accuracy was also checked by comparison of the results of the proposed method with those found by a method based on a microwave-assisted digestion of real samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Dissolution and secondary mineral precipitation in basalts due to reactions with carbonic acid

    Science.gov (United States)

    Kanakiya, Shreya; Adam, Ludmila; Esteban, Lionel; Rowe, Michael C.; Shane, Phil

    2017-06-01

    One of the leading hydrothermal alteration processes in volcanic environments is when rock-forming minerals with high concentrations of iron, magnesium, and calcium react with CO2 and water to form carbonate minerals. This is used to the advantage of geologic sequestration of anthropogenic CO2. Here we experimentally investigate how mineral carbonation processes alter the rock microstructure due to CO2-water-rock interactions. In order to characterize these changes, CO2-water-rock alteration in Auckland Volcanic Field young basalts (less than 0.3 Ma) is studied before and after a 140 day reaction period. We investigate how whole core basalts with similar geochemistry but different porosity, permeability, pore geometry, and volcanic glass content alter due to CO2-water-rock reactions. Ankerite and aluminosilicate minerals precipitate as secondary phases in the pore space. However, rock dissolution mechanisms are found to dominate this secondary mineral precipitation resulting in an increase in porosity and decrease in rigidity of all samples. The basalt with the highest initial porosity and volcanic glass volume shows the most secondary mineral precipitation. At the same time, this sample exhibits the greatest increase in porosity and permeability, and a decrease in rock rigidity post reaction. For the measured samples, we observe a correlation between volcanic glass volume and rock porosity increase due to rock-fluid reactions. We believe this study can help understand the dynamic rock-fluid interactions when monitoring field scale CO2 sequestration projects in basalts.

  20. Uncertainty Assessment: Reservoir Inflow Forecasting with Ensemble Precipitation Forecasts and HEC-HMS

    Directory of Open Access Journals (Sweden)

    Sheng-Chi Yang

    2014-01-01

    Full Text Available During an extreme event, having accurate inflow forecasting with enough lead time helps reservoir operators decrease the impact of floods downstream. Furthermore, being able to efficiently operate reservoirs could help maximize flood protection while saving water for drier times of the year. This study combines ensemble quantitative precipitation forecasts and a hydrological model to provide a 3-day reservoir inflow in the Shihmen Reservoir, Taiwan. A total of six historical typhoons were used for model calibration, validation, and application. An understanding of cascaded uncertainties from the numerical weather model through the hydrological model is necessary for a better use for forecasting. This study thus conducted an assessment of forecast uncertainty on magnitude and timing of peak and cumulative inflows. It found that using the ensemble-mean had less uncertainty than randomly selecting individual member. The inflow forecasts with shorter length of cumulative time had a higher uncertainty. The results showed that using the ensemble precipitation forecasts with the hydrological model would have the advantage of extra lead time and serve as a valuable reference for operating reservoirs.

  1. Climatic change of summer temperature and precipitation in the Alpine region - a statistical-dynamical assessment

    Energy Technology Data Exchange (ETDEWEB)

    Heimann, D.; Sept, V.

    1998-12-01

    Climatic changes in the Alpine region due to increasing greenhouse gas concentrations are assessed by using statistical-dynamical downscaling. The downscaling procedure is applied to two 30-year periods (1971-2000 and 2071-2100, summer months only) of the output of a transient coupled ocean/atmosphere climate scenario simulation. The downscaling results for the present-day climate are in sufficient agreement with observations. The estimated regional climate change during the next 100 years shows a general warming. The mean summer temperatures increase by about 3 to more than 5 Kelvin. The most intense climatic warming is predicted in the western parts of the Alps. The amount of summer precipitation decreases in most parts of central Europe by more than 20 percent. Only over the Adriatic area and parts of eastern central Europe an increase in precipitation is simulated. The results are compared with observed trends and results of regional climate change simulations of other authors. The observed trends and the majority of the simulated trends agree with our results. However, there are also climate change estimates which completely contradict with ours. (orig.) 29 refs.

  2. Acidification of lakes in Canada by acid precipitation and the resulting effects on fishes

    Science.gov (United States)

    Richard J. Beamish

    1976-01-01

    There are several areas in Canada that could receive acidic fallout. Only in the area that produces Canada's largest single source of sulfur oxides has there been appreciable research. In the Sudbury region of Ontario, Canada, fallout of sulfur oxides has been shown to be responsible for damage to vegetation, lakes and fishes. The acidic fallout has been shown to...

  3. County-Level Climate Uncertainty for Risk Assessments: Volume 8 Appendix G - Historical Precipitation.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.; Lowry, Thomas Stephen; Jones, Shannon M; Walker, La Tonya Nicole; Roberts, Barry L; Malczynski, Leonard A.

    2017-06-01

    This report uses the CMIP5 series of climate model simulations to produce country- level uncertainty distributions for use in socioeconomic risk assessments of climate change impacts. It provides appropriate probability distributions, by month, for 169 countries and autonomous-areas on temperature, precipitation, maximum temperature, maximum wind speed, humidity, runoff, soil moisture and evaporation for the historical period (1976-2005), and for decadal time periods to 2100. It also provides historical and future distributions for the Arctic region on ice concentration, ice thickness, age of ice, and ice ridging in 15-degree longitude arc segments from the Arctic Circle to 80 degrees latitude, plus two polar semicircular regions from 80 to 90 degrees latitude. The uncertainty is meant to describe the lack of knowledge rather than imprecision in the physical simulation because the emphasis is on unfalsified risk and its use to determine potential socioeconomic impacts. The full report is contained in 27 volumes.

  4. Assessment of WRF microphysics schemes to simulate extreme precipitation events from the perspective of GMI radiative signatures

    Science.gov (United States)

    Choi, Y.; Shin, D. B.; Joh, M.

    2015-12-01

    Numerical simulations of precipitation depend to a large degree on the assumed cloud microphysics schemes representing the formation, growth and fallout of cloud droplets and ice crystals. Recent studies show that assumed cloud microphysics play a major role not only in forecasting precipitation, especially in cases of extreme precipitation events, but also in the quality of the passive microwave rainfall estimation. Evaluations of the various Weather Research Forecasting (WRF) model microphysics schemes in this study are based on a method that was originally developed to construct the a-priori databases of precipitation profiles and associated brightness temperatures (TBs) for precipitation retrievals. This methodology generates three-dimensional (3D) precipitation fields by matching the GPM dual frequency radar (DPR) reflectivity profiles with those calculated from cloud resolving model (CRM)-derived hydrometeor profiles. The method eventually provides 3D simulated precipitation fields over the DPR scan swaths. That is, atmospheric and hydrometeor profiles can be generated at each DPR pixel based on CRM and DPR reflectivity profiles. The generated raining systems over DPR observation fields can be applied to any radiometers that are unaccompanied with a radar for microwave radiative calculation with consideration of each sensor's channel and field of view. Assessment of the WRF model microphysics schemes for several typhoon cases in terms of emission and scattering signals of GMI will be discussed.

  5. Towards an Event Based Indicator for Monitoring Change in Extreme Precipitation in Support of the US National Climate Assessment

    Science.gov (United States)

    Slinskey, E. A.; Loikith, P. C.; Waliser, D. E.

    2016-12-01

    Extreme precipitation events are associated with numerous societal and environmental impacts. Recent observational analysis suggests increasing trends in precipitation intensity across portions of the Continental United States (CONUS) consistent with expectations associated with anthropogenic climate change. Therefore, a spatial understanding and intuitive means of monitoring extreme precipitation over time is critical. In support of the ongoing efforts of the US National Climate Assessment (NCA), we present a gridded climate indicator, based on high-resolution gridded NASA satellite-based precipitation data from NASA's Tropical Rainfall Measuring Mission (TRMM) and the Global Precipitation Measurement (GPM) product, to monitor and track extreme precipitation events over the CONUS. The indicator is based on categorized storm totals over the CONUS defined as 3-day total accumulated precipitation events, ensuring a spatially and temporally balanced regional representation of synoptic-scale and short-duration storm events alike. A precipitation categorization scheme mirroring that of the widely understood Saffir-Simpson hurricane intensity index is assigned to each 3-day precipitation event with each precipitation category referred to as a P-Cat. The magnitude of each event lies between P-Cat 1, the lightest category of storm totals, and P-Cat 5, the heaviest, allowing for easy interpretation and visualization. With all precipitation events assigned to a P-Cat, point-wise statistics are computed across the CONUS including the maximum P-Cat, the mean P-Cat, and the frequency of each P-Cat at each grid point providing a comprehensive climatology of precipitation event intensity and a baseline for monitoring change. A novel aspect of this indicator is that it will accurately display discernable spatial variations with regional specificity in extreme precipitation event frequency and intensity over relevant temporal scales. Changes in variability will be observable at

  6. Molecularly imprinted polymer for chlorogenic acid by modified precipitation polymerization and its application to extraction of chlorogenic acid from Eucommia ulmodies leaves.

    Science.gov (United States)

    Miura, Chitose; Li, Hui; Matsunaga, Hisami; Haginaka, Jun

    2015-10-10

    Molecularly imprinted polymers (MIPs) for chlorogenic acid (CGA) were prepared by modified precipitation polymerization using methacrylic acid as a functional monomer, divinylbenzene as a crosslinker and methanol or dimethylsulfoxide as a co-solvent. The prepared MIPs were microspheres with a narrow particle size distribution. Binding experiments and Scatchard analyses revealed that two classes of binding sites, high and low affinity sites, were formed on the MIP. The retention and molecular-recognition properties of the prepared MIP were evaluated using a mixture of water and acetonitrile as a mobile phase in hydrophilic interaction chromatography. With an increase of acetonitrile content, the retention factor of CGA was increased on the MIP. In addition to shape recognition, hydrophilic interactions seem to work for the recognition of CGA on the MIP. The MIP had a specific molecular-recognition ability for CGA, while other related compounds, such as caffeic acid, gallic acid, protocatechuic acid and vanillic acid, could not be recognized by the MIP. Furthermore, the MIP for CGA was successfully applied for extraction of CGA in the leaves of Eucommia ulmodies. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Assessing the Impact of Pre-gpm Microwave Precipitation Observations in the Goddard WRF Ensemble Data Assimilation System

    Science.gov (United States)

    Chambon, Philippe; Zhang, Sara Q.; Hou, Arthur Y.; Zupanski, Milija; Cheung, Samson

    2013-01-01

    The forthcoming Global Precipitation Measurement (GPM) Mission will provide next generation precipitation observations from a constellation of satellites. Since precipitation by nature has large variability and low predictability at cloud-resolving scales, the impact of precipitation data on the skills of mesoscale numerical weather prediction (NWP) is largely affected by the characterization of background and observation errors and the representation of nonlinear cloud/precipitation physics in an NWP data assimilation system. We present a data impact study on the assimilation of precipitation-affected microwave (MW) radiances from a pre-GPM satellite constellation using the Goddard WRF Ensemble Data Assimilation System (Goddard WRF-EDAS). A series of assimilation experiments are carried out in a Weather Research Forecast (WRF) model domain of 9 km resolution in western Europe. Sensitivities to observation error specifications, background error covariance estimated from ensemble forecasts with different ensemble sizes, and MW channel selections are examined through single-observation assimilation experiments. An empirical bias correction for precipitation-affected MW radiances is developed based on the statistics of radiance innovations in rainy areas. The data impact is assessed by full data assimilation cycling experiments for a storm event that occurred in France in September 2010. Results show that the assimilation of MW precipitation observations from a satellite constellation mimicking GPM has a positive impact on the accumulated rain forecasts verified with surface radar rain estimates. The case-study on a convective storm also reveals that the accuracy of ensemble-based background error covariance is limited by sampling errors and model errors such as precipitation displacement and unresolved convective scale instability.

  8. The effects of a simulated acid precipitation on leaf litter quality and the growth of a detritivore in a buffered lotic system.

    Science.gov (United States)

    Garden, A; Davies, R W

    1988-01-01

    The effects of a simulated acid rain on leaf litter quality and the growth of a detritivore in a buffered lotic system were investigated. Exposure of Populus balsamifera L. saplings to a simulated acid precipitation prior to leaf abscission resulted in significant decreases in foliar nitrogen content and increases in carbon: nitrogen ratios. During decomposition of the leaf litter in a buffered lotic system, microbial activity was significantly reduced. Growth of Tipula commiscibilis Diane (Diptera: Tipulidae) larvae decreased significantly when fed conditioned leaves exposed to a simulated acid precipitation prior to abscission. Reductions in detritivore growth were correlated with lower potential quality of the leaf litter resulting from increased carbon: nitrogen ratios and reduced levels of microbial activity. Thus, even in well buffered freshwater ecosystems, acid precipitation can have significant indirect effects on microbial activity and macroinvertebrate growth.

  9. 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.

  10. Soluble species in the Arctic summer troposphere - Acidic gases, aerosols, and precipitation

    Science.gov (United States)

    Talbot, R. W.; Vijgen, A. S.; Harriss, R. C.

    1992-01-01

    The large-scale spatial distribution from 0.15-to 6 km altitude in the North American Arctic troposphere of several soluble acidic gases and major aerosol species during the summertime is reported. The distribution is found to be compositionally consistent on a large spatial scale. The summertime troposphere is an acidic environment, with HCOOH and CH3COOH the principal acidic gases while acidic sulfate aerosols dominate the particulate phase. There appears to be a surface source of NH3 over the pack ice which may originate from decay of dead marine organisms on the ice surface, evolution from surface ocean waters in open ice leads, or release from rotting sea ice. At low altitude over the pack ice this NH34 appears to partially neutralize aerosol acidity. Over sub-Arctic tundra in southeastern Alaska, inputs of marine biogenic sulfur from the Bering Sea appear to be an important source of boundary layer aerosol SO4(2-). The rainwater acidity over the tundra is typical of remote regions.

  11. Ammonia-oxidizing archaea are more resistant than denitrifiers to seasonal precipitation changes in an acidic subtropical forest soil

    Science.gov (United States)

    Chen, Jie

    2017-04-01

    More frequent droughts and storms will occur globally in the prediction of global climate change model, which will influence soil microorganisms and nutrient cycles. Understanding the resistance of soil functional microorganisms and the associated biogeochemical cycles to such climate changes is important in evaluating responses of ecosystem functioning. In order to clarify the responses of soil functional microorganisms involved in nitrogen (N) cycle to the predicted precipitation scenarios, two contrasting precipitation manipulation experiments were conducted in an acidic subtropical forest soil. One experiment manipulated drier dry-season and wetter wet-season (DD) by reducing dry-season rainfall and adding the equivalently reduced rainfall to wet-season. Another experiment manipulated extending dry-season and wetter wet-season (ED) by reducing spring-season rainfall and adding the equivalent rainfall in the late wet-season. The resistance index of ammonia-oxidizing archaea (AOA) amoA and denitrifying (nirK, nirS and nosZ) genes abundance, soil net N mineralization and nitrification rates were calculated during experiments to examine their responses to precipitation changes. As the results, the resistance index of functional microbial abundance (-0.03 ± 0.08) was much lower than that of net N transformation rates (0.55 ± 0.02), indicating more sensitive of functional microorganisms in response to precipitation changes than the related N processes. Extending dry-season showed greater effects on both AOA amoA and denitrifying genes abundance than drier dry-season, with significant increases of these microbial abundance after extending dry-season. This was mainly due to the interaction effects of soil water content (SWC), dissolve organic carbon (DOC) and NH4+ concentration during rainfall reduction in spring-season. Interestingly, the resistance index of AOA amoA abundance was significantly higher than that of denitrifying gene abundance, indicating more

  12. Synthesis of WO{sub 3} nanoparticles by citric acid-assisted precipitation and evaluation of their photocatalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez-Martínez, D. [Departamento de Ecomateriales y Energía, Facultad de Ingeniería Civil (UANL), Ciudad Universitaria, C.P. 66451, San Nicolás de los Garza, N.L. (Mexico); Martínez-de la Cruz, A., E-mail: azael70@yahoo.com.mx [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451, San Nicolás de los Garza, N.L. (Mexico); López-Cuéllar, E. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451, San Nicolás de los Garza, N.L. (Mexico)

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► WO{sub 3} nanoparticles were synthesized by a simple citric acid-assisted precipitation. ► WO{sub 3} photocatalyst was able to the partial mineralization of rhB, IC and MO. ► WO{sub 3} can be considered as a photocatalyst active under visible light irradiation. -- Abstract: WO{sub 3} nanoparticles were synthesized by citric acid-assisted precipitation method using a 1:1.5 molar ratio of ammonium paratungstate hydrate (H{sub 42}N{sub 10}O{sub 42}W{sub 12}·xH{sub 2}O):citric acid (C{sub 6}H{sub 8}O{sub 7}). The formation of monoclinic crystal structure of WO{sub 3} at different temperatures was confirmed by X-ray powder diffraction (XRD). The characterization of the samples synthesized was complemented by transmission electron microscopy (TEM), Brunauer–Emmitt–Teller surface area (BET) and diffuse reflectance spectroscopy (DRS). According to the thermal treatment followed during the synthesis of WO{sub 3}, the morphology of the nanoparticles formed was characterized by rectangular and ovoid shapes. The photocatalytic activity of WO{sub 3} obtained under different experimental conditions was evaluated in the degradation of rhodamine B (rhB), indigo carmine (IC), methyl orange (MO), and Congo red (CR) in aqueous solution under UV and UV–vis radiation. The highest photocatalytic activity was observed in the sample obtained by thermal treatment at 700 °C. In general, the sequence of degradation of the organic dyes was: indigo carmine (IC) > rhodamine B (rhB) > methyl orange (MO) > Congo red (CR). The mineralization degree of organic dyes by WO{sub 3} photocatalysts was determined by total organic carbon analysis (TOC) reaching percentages of mineralization of 82% (rhB), 85% (IC), 28% (MO), and 7% (CR) for 96 h of lamp irradiation.

  13. A preliminary assessment of GPM-based multi-satellite precipitation estimates over a monsoon dominated region

    Science.gov (United States)

    Prakash, Satya; Mitra, Ashis K.; AghaKouchak, Amir; Liu, Zhong; Norouzi, Hamidreza; Pai, D. S.

    2018-01-01

    Following the launch of the Global Precipitation Measurement (GPM) Core Observatory, two advanced high resolution multi-satellite precipitation products namely, Integrated Multi-satellitE Retrievals for GPM (IMERG) and Global Satellite Mapping of Precipitation (GSMaP) version 6 are released. A critical evaluation of these newly released precipitation data sets is very important for both the end users and data developers. This study provides a comprehensive assessment of IMERG research product and GSMaP estimates over India at a daily scale for the southwest monsoon season (June to September 2014). The GPM-based precipitation products are inter-compared with widely used TRMM Multi-satellite Precipitation Analysis (TMPA), and gauge-based observations over India. Results show that the IMERG estimates represent the mean monsoon rainfall and its variability more realistically than the gauge-adjusted TMPA and GSMaP data. However, GSMaP has relatively smaller root-mean-square error than IMERG and TMPA, especially over the low mean rainfall regimes and along the west coast of India. An entropy-based approach is employed to evaluate the distributions of the selected precipitation products. The results indicate that the distribution of precipitation in IMERG and GSMaP has been improved markedly, especially for low precipitation rates. IMERG shows a clear improvement in missed and false precipitation bias over India. However, all the three satellite-based rainfall estimates show exceptionally smaller correlation coefficient, larger RMSE, larger negative total bias and hit bias over the northeast India where precipitation is dominated by orographic effects. Similarly, the three satellite-based estimates show larger false precipitation over the southeast peninsular India which is a rain-shadow region. The categorical verification confirms that these satellite-based rainfall estimates have difficulties in detection of rain over the southeast peninsula and northeast India. These

  14. On the use of the intensity‐scale verification technique to assess operational precipitation forecasts

    National Research Council Canada - National Science Library

    Csima, Gabriella; Ghelli, Anna

    2008-01-01

    ...‐Range Weather Forecasts (ECMWF) operational quantitative precipitation forecast (QPF) over France, and to compare the performance of the ECMWF and the Hungarian Meteorological Service operational...

  15. Kinetic and safety assessment for salicylic acid nitration by nitric acid/acetic acid system.

    Science.gov (United States)

    Andreozzi, R; Caprio, V; Di Somma, I; Sanchirico, R

    2006-06-30

    The nitration process of salicylic acid for the production of the important intermediate 5-nitrosalicylic acid is studied from thermokinetic and safety points of view. Investigations carried out by considering, as process deviations, the loss of the thermal control point out the possibility of runaway phenomena due to the occurrence of polynitration reactions. Isothermal experiments are carried out in various conditions to assess the involved reaction network and reaction kinetics.

  16. Assessing the Roles of Fire Frequency and Precipitation in Determining Woody Plant Expansion in Central U.S. Grasslands

    Science.gov (United States)

    Brunsell, N. A.; Van Vleck, E. S.; Nosshi, M.; Ratajczak, Z.; Nippert, J. B.

    2017-10-01

    Woody plant expansion into grasslands and savannas is occurring and accelerating worldwide and often impacts ecosystem processes. Understanding and predicting the environmental and ecological impacts of encroachment has led to a variety of methodologies for assessing its onset, transition, and stability, generally relying on dynamical systems approaches. Here we continue this general line of investigation to facilitate the understanding of the roles of precipitation frequency and intensity and fire frequency on the conversion of grasslands to woody-dominated systems focusing on the central United States. A low-dimensional model with stochastic precipitation and fire disturbance is introduced to examine the complex interactions between precipitation and fire as mechanisms that may suppress or facilitate increases in woody cover. By using Lyapunov exponents, we are able to ascertain the relative control exerted on woody encroachment through these mechanisms. Our results indicate that precipitation frequency is a more important control on woody encroachment than the intensity of individual precipitation events. Fire, however, exerts a much more dominant impact on the limitation of encroachment over the range of precipitation variability considered here. These results indicate that fire management may be an effective strategy to slow the onset of woody species into grasslands. While climate change might predict a reduced potential for woody encroachment in the near future, these results indicate a reduction in woody fraction may be unlikely when considering anthropogenic fire suppression.

  17. Acidic weathering of carbonate building stones: experimental assessment

    Directory of Open Access Journals (Sweden)

    Ryszard Kryza

    2009-06-01

    Full Text Available Three types of carbonate rocks, travertine, limestone and marble have been studied to determine their selected technical parameters (water absorption, resistance to salt crystallization damage and reaction to experimentally modelled acid rain weathering imitating the polluted urban atmospheric conditions. The acidic agents present in natural acid rain precipitation, H2SO4, HCl, HNO3, CH3COOH and mixture of all the acids, “Acid mix”, were tested. The initial stages of acid weathering involve, apart from chemical dissolution, particularly intense physical detachment of rock particles (granular disintegration significantly contributing to the total mass loss. Travertine was found to be most prone to salt crystallization damage and to acid weathering, and these features should be taken into account especially in external architectural usage of this stone in cold climate conditions and polluted urban atmosphere.

  18. Collection and Generation of Sulfuric Acid Aerosols in a Wet Electrostatic Precipitator

    National Research Council Canada - National Science Library

    Anderlohr, C; Brachert, L; Mertens, J; Schaber, K

    2015-01-01

    .... It is suspected that the reactive species produced in the nonthermal plasma of the corona discharge oxidize the SO 2 to SO 3 which forms sulfuric acid. This causes supersaturation with subsequent homogeneous nucleation and thus aerosol formation. Copyright 2015 American Association for Aerosol Research

  19. Aquatic Activities for Middle School Children. A Focus on the Effects of Acid Precipitation.

    Science.gov (United States)

    Minnesota Univ., Minneapolis. Minnesota Sea Grant Program.

    Basic water-related concepts and underlying principles of acid rain are described in this curriculum in a manner that young children can understand. The curriculum consists of activities presented in four units: Background Unit, Earth Science Unit, Life Science Unit, and Extension Unit. The first three units consist of several modules, each module…

  20. Synthesis of carbon supported palladium nanoparticles catalyst using a facile homogeneous precipitation-reduction reaction method for formic acid electrooxidation

    Science.gov (United States)

    Ma, Juan; Ji, Yigang; Sun, Hanjun; Chen, Yu; Tang, Yawen; Lu, Tianhong; Zheng, Junwei

    2011-10-01

    A highly dispersed and ultrafine carbon supported Pd nanoparticles (Pd/C) catalyst is synthesized by a facile homogeneous precipitation-reduction reaction method. Under the appropriate pH conditions, [PdCl 4] 2- species in PdCl 2 solution are slowly transformed into the insoluble palladium oxide hydrate (PdO·H 2O) precipitation by heat treatment due to a slow hydrolysis reaction, which results in the generation of carbon supported PdO·H 2O nanoparticles (PdO·H 2O/C) sample with the high dispersion and small particle size. Consequently, a highly dispersed and ultrafine Pd/C catalyst can be synthesized by PdO·H 2O → Pd 0 in situ reduction reaction path in the presence of NaBH 4. As a result, the resulting Pd/C catalyst possesses a significantly electrocatalytic performance for formic acid electrooxidation, which is attributed to the uniformly sized and highly dispersed nanostructure.

  1. A novel high-pressure precipitation tandem homogenization technology for drug nanocrystals production - a case study with ursodeoxycholic acid.

    Science.gov (United States)

    Li, Yu; Wang, Yong; Yue, Peng-Fei; Hu, Peng-Yi; Wu, Zhen-Feng; Yang, Ming; Yuan, Hai-Long

    2014-09-01

    To overcome the limitations of the conventional particle size reduction technologies, a novel combinative particle size reduction method for the effective production of homogeneous nanosuspensions was investigated. Ursodeoxycholic acid, a poorly soluble drug representative, was tried to prepare nanosuspension by homogenization technology and high-pressure precipitation tandem homogenization technology. It was shown that the combinative approach could significantly improve the particle size reduction effectiveness over conventional homogenization approach. The Box-Behnken design analysis for process optimization revealed that the acceptable UDCA-NS was obtained wherein the optimal values of A, B, C and D were 10%, 500 bar, 0.125 and 600 bar, respectively. SEM results demonstrated that no significant aggregation or crystals growth could be observed in the freeze-dried UDCA nanocrystals. The DSC and XRD results showed that UDCA remained in a crystalline state. Dissolution velocities of the freeze-dried UDCA-NS powder were distinctly superior compared to those of the crude powder and physical mixture. The high-pressure precipitation tandem homogenization technology can be a good choice for nanosuspension preparation of poorly soluble UDCA, due to high efficiency of particle size reduction.

  2. Flavianate, an amino acid precipitant, is a competitive inhibitor of trypsin at pH 3.0

    Directory of Open Access Journals (Sweden)

    J.M. Schneedorf

    1998-09-01

    Full Text Available Textile dyes bind to proteins leading to selective co-precipitation of a complex involving one protein molecule and more than one dye molecule of opposite charge in acid solutions, in a process of reversible denaturation that can be utilized for protein fractionation. In order to understand what occurs before the co-precipitation, a kinetic study using bovine ß-trypsin and sodium flavianate was carried out based on reaction progress curve techniques. The experiments were carried out using a-CBZ-L-Lys-p-nitrophenyl ester as substrate which was added to 50 mM sodium citrate buffer, pH 3.0, containing varying concentrations of ß-trypsin and dye. The reaction was recorded spectrophotometrically at 340 nm for 30 min, and the families of curves obtained were analyzed simultaneously by fitting integrated Michaelis-Menten equations. The dye used behaved as a competitive inhibitor of trypsin at pH 3.0, with Ki = 99 µM; kinetic parameters for the substrate hydrolysis were: Km = 32 µM, and kcat = 0.38/min. The competitive character of the inhibition suggests a specific binding of the first dye molecule to His-57, the only positively charged residue at the active site of the enzyme.

  3. Production and characterization of poly(3-hydroxybutyrate) generated by Alcaligenes latus using lactose and whey after acid protein precipitation process.

    Science.gov (United States)

    Berwig, Karina Hammel; Baldasso, Camila; Dettmer, Aline

    2016-10-01

    Whey after acid protein precipitation was used as substrate for PHB production in orbital shaker using Alcaligenes latus. Statistical analysis determined the most appropriate hydroxide for pH neutralization of whey after protein precipitation among NH4OH, KOH and NaOH 10%w/v. The results were compared to those of commercial lactose. A scale-up test in a 4L bioreactor was done at 35°C, 750rpm, 7L/min air flow, and 6.5 pH. The PHB was characterized through Fourier Transform Infrared Spectroscopy, thermogravimetry and differential scanning calorimetry. NH4OH provided the best results for productivity (p), 0.11g/L.h, and for polymer yield, (YP/S), 1.08g/g. The bioreactor experiment resulted in lower p and YP/S. PHB showed maximum degradation temperature (291°C), melting temperature (169°C), and chemical properties similar to those of standard PHB. The use of whey as a substrate for PHB production did not affect significantly the final product quality. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Circulation type classifications as a tool to assess variability of precipitation extremes in Southern Germany and Austria

    Science.gov (United States)

    Homann, Markus; Jacobeit, Jucundus; Beck, Christoph; Philipp, Andreas; Hofstätter, Michael; Chimani, Barbara; Ganekind, Manfred

    2013-04-01

    Excessive large-scale precipitation events cause an increasing risk of severe floodings. For example in 2002 and 2005 Vb cyclones led to extreme flooding events in Central Europe. The aspect of ongoing climate change makes a valid assessment of the regional flooding potential in dependence of different circulation types and cyclone track types even more important. The present study refers to Southern Germany and Austria for which a gridded daily precipitation set with 6km horizontal resolution is available for the 1951-2007 period. S-mode principal component analysis (PCA) is applied to determine regions with similar precipitation variability. Extreme precipitation events are defined by the 95th percentiles of daily precipitation during the standard seasons (DJF, MAM, JJA, SON). Large-scale circulation types are derived by different statistical methods using the COST733 classification software and different re-analysis data. To assess the performance of particular circulation type classifications with respect to regional precipitation extremes, the Brier-Skill-Score (BSS) has been applied. For Southern Germany and Austria the regionalization of precipitation variability results in seasonally varying numbers and spatial extents of 'rainfall regions'. Concerning relationships between large-scale dynamics and regional impacts, the general conclusion is that in more sub-continental regions, the dependency between circulation types and precipitation extremes is less pronounced than in sub-oceanic regions. This fact is much clearer in winter than in summer. Further results show that in these two areas different classification methods (threshold-based and optimizing ones) lead to most valid results. After further improving the performance of circulation type classifications, future extreme precipitation events under enhanced greenhouse warming conditions will be estimated by using output from CMIP5 Global Climate Models for the synoptic downscaling from large

  5. An assessment of differences in gridded precipitation datasets in complex terrain

    Science.gov (United States)

    Henn, Brian; Newman, Andrew J.; Livneh, Ben; Daly, Christopher; Lundquist, Jessica D.

    2018-01-01

    Hydrologic modeling and other geophysical applications are sensitive to precipitation forcing data quality, and there are known challenges in spatially distributing gauge-based precipitation over complex terrain. We conduct a comparison of six high-resolution, daily and monthly gridded precipitation datasets over the Western United States. We compare the long-term average spatial patterns, and interannual variability of water-year total precipitation, as well as multi-year trends in precipitation across the datasets. We find that the greatest absolute differences among datasets occur in high-elevation areas and in the maritime mountain ranges of the Western United States, while the greatest percent differences among datasets relative to annual total precipitation occur in arid and rain-shadowed areas. Differences between datasets in some high-elevation areas exceed 200 mm yr-1 on average, and relative differences range from 5 to 60% across the Western United States. In areas of high topographic relief, true uncertainties and biases are likely higher than the differences among the datasets; we present evidence of this based on streamflow observations. Precipitation trends in the datasets differ in magnitude and sign at smaller scales, and are sensitive to how temporal inhomogeneities in the underlying precipitation gauge data are handled.

  6. Ultra-Small Fatty Acid-Stabilized Magnetite Nanocolloids Synthesized by In Situ Hydrolytic Precipitation

    Directory of Open Access Journals (Sweden)

    Kheireddine El-Boubbou

    2015-01-01

    Full Text Available Simple, fast, large-scale, and cost-effective preparation of uniform controlled magnetic nanoparticles remains a major hurdle on the way towards magnetically targeted applications at realistic technical conditions. Herein, we present a unique one-pot approach that relies on simple basic hydrolytic in situ coprecipitation of inexpensive metal salts (Fe2+ and Fe3+ compartmentalized by stabilizing fatty acids and aided by the presence of alkylamines. The synthesis was performed at relatively low temperatures (~80°C without the use of high-boiling point solvents and elevated temperatures. This method allowed for the production of ultra-small, colloidal, and hydrophobically stabilized magnetite metal oxide nanoparticles readily dispersed in organic solvents. The results reveal that the obtained magnetite nanoparticles exhibit narrow size distributions, good monodispersities, high saturation magnetizations, and excellent colloidal stabilities. When the [fatty acid] : [Fe] ratio was varied, control over nanoparticle diameters within the range of 2–10 nm was achieved. The amount of fatty acid and alkylamine used during the reaction proved critical in governing morphology, dispersity, uniformity, and colloidal stability. Upon exchange with water-soluble polymers, the ultra-small sized particles become biologically relevant, with great promise for theranostic applications as imaging and magnetically targeted delivery vehicles.

  7. Assessment of realistic nowcasting lead-times based on predictability analysis of Mediterranean Heavy Precipitation Events

    Science.gov (United States)

    Bech, Joan; Berenguer, Marc

    2014-05-01

    Operational quantitative precipitation forecasts (QPF) are provided routinely by weather services or hydrological authorities, particularly those responsible for densely populated regions of small catchments, such as those typically found in Mediterranean areas prone to flash-floods. Specific rainfall values are used as thresholds for issuing warning levels considering different time frameworks (mid-range, short-range, 24h, 1h, etc.), for example 100 mm in 24h or 60 mm in 1h. There is a clear need to determine how feasible is a specific rainfall value for a given lead-time, in particular for very short range forecasts or nowcasts typically obtained from weather radar observations (Pierce et al 2012). In this study we assess which specific nowcast lead-times can be provided for a number of heavy precipitation events (HPE) that affected Catalonia (NE Spain). The nowcasting system we employed generates QPFs through the extrapolation of rainfall fields observed with weather radar following a Lagrangian approach developed and tested successfully in previous studies (Berenguer et al. 2005, 2011).Then QPFs up to 3h are compared with two quality controlled observational data sets: weather radar quantitative precipitation estimates (QPE) and raingauge data. Several high-impact weather HPE were selected including the 7 September 2005 Llobregat Delta river tornado outbreak (Bech et al. 2007) or the 2 November 2008 supercell tornadic thunderstorms (Bech et al. 2011) both producing, among other effects, local flash floods. In these two events there were torrential rainfall rates (30' amounts exceeding 38.2 and 12.3 mm respectively) and 24h accumulation values above 100 mm. A number of verification scores are used to characterize the evolution of precipitation forecast quality with time, which typically presents a decreasing trend but showing an strong dependence on the selected rainfall threshold and integration period. For example considering correlation factors, 30

  8. Recovery of nickel from spent NiO/Al2O3 catalyst through sulfuric acid leaching, precipitation and solvent extraction.

    Science.gov (United States)

    Nazemi, M K; Rashchi, F

    2012-05-01

    Effective recovery of nickel (Ni) from spent NiO/Al(2)O(3) catalyst in a simple hydrometallurgical route is suggested. Nickel recovery of 99.5% was achieved with sulfuric acid leaching. The leach liquor was partly neutralized and nickel ammonium sulfate was precipitated by adding ammonia. The nickel in the supernatant was concentrated by solvent extraction using D2EHPA and subsequently stripped back into sulfuric acid and returned to the precipitation stage. Necessary counter current extraction and stripping stages were determined in McCabe-Thiele diagrams. The suggested method appears simple and very effective in recovering nickel from spent catalysts from the petrochemical industry.

  9. SEM/EDS characterisation of dusty deposits in precipitation and assessment of their origin

    Directory of Open Access Journals (Sweden)

    Miloš Miler

    2014-07-01

    Full Text Available Detailed scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS analysis of dusty material in rainfall residue, deposited and collected on February 19th 2014 in Ljubljana, was carried out with the intention to characterise it according to its chemical and mineral composition and to assess its origin. The material consists of poorly sorted and sharp-edged particles of mostly very fine-grained silt and clay fractions, which is consistent with long-range aerial transport. Particles are represented by illite, chlorite and kaolinite group clay minerals, quartz, feldspars, carbonates, accessory minerals and secondary Fe-oxy-hydroxide minerals. Quantities of minerals and illite/ kaolinite ratio (4.5 correspond to dusts in rainfall residues originating from Moroccan Atlas, while chlorite/kaolinite ratio (2.8 agrees better with dust from central Libya. The element ratios Al/Si, Ca/Al, K/Ca, Mg/Al, Fe/Al and (Ca+Mg/Fe in the studied dusty deposit are in good agreement with ratios in dusts from rainfall residues originating from Morocco and northern Mauritania. This was also confirmed by the trajectories of cloud movement that caused precipitation with dusty deposit, although the back trajectory HYSPLIT simulation of air masses indicated northern Mauritania, central Niger, southern Algeria, southwestern and central Libya as the most possible source regions.

  10. Proceedings of the international workshop on the effects of acid precipitation on vegetation, soils, and terrestrial ecosystems, Brookhaven National Laboratory, June 12 to 14, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Evans, L.S.; Hendrey, G.R. (eds.)

    1979-01-01

    The objectives of the workshop were to determine the levels of current knowledge of the effects of acid precipitation on vegetation, soils, and terrestrial ecosystems; research needed in these areas to understand the environmental impacts of acid rain; and to help coordinate research groups to avoid excessive duplication of research. The workshop was designed so that researchers in the areas of effects of acid precipitation on vegetation, soils, and whole ecosystem approaches could communicate effectively. There was a general consensus that acid rain at extreme ambient levels, or in artificial systems that simulate extreme ambient levels, causes injury to plant tissues. A major area of concern of acid rain injury was thought to be plant reproduction. The overall levels of significance of plant injury among various plant species remain unknown. The most important priorities in the area of effects of acid rain on crops were an evaluation of effects on crop yields and interaction of acid rain in combination with pollutants on various plants. Few participants thought that ambient acid rain loadings have altered soils to such a degree that plants are affected at present, but many thought that acid rain could cause some alterations in soils. The most important research priorities were in the areas of the effects of acid rain on increased leaching of exchangeable plant nutrients and alterations in phosphorous availability. All participants agreed that there are alterations in terrestrial ecosystems from acid precipitation. However, no demonstrated harmful effects were presented from natural ecosystems. Further research on the effects of acid rain on terrestrial ecosystems should be directed mostly toward the interaction of acid rain with toxic elements such as Al, Fe, and Mn and on the effects on nutrient cycling, especially that of nitrogen.

  11. The effect of random precipitation times on the scavenging rate for tropospheric nitric acid

    Science.gov (United States)

    Stewart, Richard W.

    1988-01-01

    A model for the effective scavenging rate of a soluble species has been developed. The model takes into account the possibility of positive as well as negative correlations between departures from the mean of the scavenging rate and species concentration. The model is demonstrated for the case of late afternoon rainout of nitric acid occurring just prior to the nighttime cessation of its chemical production. The calculations give effective scavenging rates which are about a factor of 2 to 3 greater than those calculated using the models of Rodhe and Grandell (1972) and Giorgi and Chameides (1985).

  12. Assessment of the consistency among global precipitation products over the United Arab Emirates

    Directory of Open Access Journals (Sweden)

    Youssef Wehbe

    2017-08-01

    New hydrological insights for the region: The UAE, similar to other dryland environments lacking adequate hydrologic monitoring networks, presents a unique area to evaluate satellite remote sensing products and the erratic spatiotemporal nature of precipitation in diverse environments. Statistical analyses indicate that the TMPA V7 precipitation products record the highest overall agreement with the observational network. Within the UAE, areas that receive high rainfall and fall within the vegetated highlands (e.g., >250 m, provide the most promise for incorporating satellite precipitation into hydrologic monitoring, modeling, or water resource management.

  13. Application of Standardized Precipitation Index to assess meteorological drought in Bangladesh

    Directory of Open Access Journals (Sweden)

    Md. Anarul H. Mondol

    2016-03-01

    Full Text Available Bangladesh is one of the vulnerable countries of the world for natural disasters. Drought is one of the common and severe calamities in Bangladesh that causes immense suffering to people in various ways. The present research has been carried out to examine the frequency of meteorological droughts in Bangladesh using the long-term rainfall data of 30 meteorological observatories covering the period of 1948–2011. The study uses the highly effective Standardized Precipitation Index (SPI for drought assessment in Bangladesh. By assessing the meteorological droughts and the history of meteorological droughts of Bangladesh, the spatial distributions of meteorological drought indices were also analysed. The spatial and temporal changes in meteorological drought and changes in different years based on different SPI month intervals were analysed. The results indicate that droughts were a normal and recurrent feature and it occurred more or less all over the country in virtually all climatic regions of the country. As meteorological drought depends on only rainfall received in an area, anomaly of rainfall is the main cause of drought. Bangladesh experienced drought in the years 1950, 1951, 1953, 1954, 1957, 1958, 1960, 1961, 1962, 1963, 1965, 1966, 1967 and 1971 before independence and after independence Bangladesh has experienced droughts in the years 1972, 1973, 1975, 1979, 1980, 1983, 1985, 1992, 1994, 1995, 2002, 2004, 2006, 2009 and 2011 during the period 1948–2011. The study indicated that Rajshahi and its surroundings, in the northern regions and Jessore and its surroundings areas, the island Bhola and surrounding regions, in the south-west region, were vulnerable. In the Sylhet division, except Srimongal, the areas were not vulnerable but the eastern southern sides of the districts Chittagong, Rangamati, Khagrachhari, Bandarban and Teknaf were vulnerable. In the central regions, the districts of Mymensingh and Faridpur were more vulnerable

  14. An integrated assessment of the impact of precipitation and groundwater on vegetation growth in arid and semiarid areas

    CERN Document Server

    Zhu, Lin; Dai, Zhenxue; Xu, Tingbao; Su, Xiaosi

    2014-01-01

    Increased demand for water resources together with the influence of climate change has degraded water conditions which support vegetation in many parts of the world, especially in arid and semiarid areas. This study develops an integrated framework to assess the impact of precipitation and groundwater on vegetation growth in the Xiliao River Plain of northern China. The integrated framework systematically combines remote sensing technology with water flow modeling in the vadose zone and field data analysis. The vegetation growth is quantitatively evaluated with the remote sensing data by the Normalized Difference Vegetation Index (NDVI) and the simulated plant water uptake rates. The correlations among precipitation, groundwater depth and NDVI are investigated by using Pearson correlation equations. The results provide insights for understanding interactions between precipitation and groundwater and their contributions to vegetation growth. Strong correlations between groundwater depth, plant water uptake and...

  15. Jarosite Precipitation from Acidic Saline Waters in Kachchh, Gujarat, India: an Appropriate Martian Analogue?

    Science.gov (United States)

    Mitra, S.; Gupta, S.; Bhattacharya, S.; Banerjee, S.; Chauhan, P.; Parthasarathy, G.

    2014-12-01

    The origin of jarosite [KFe3(SO4)2(OH)6] on the Martian surface has been an intriguing problem since the Mars Exploration Rover 'Opportunity' first revealed its presence at the Meridiani Planum on Mars. To explain its origin, several terrestrial analogue sites have been studied in different geographical zones. Although several models have been suggested, there is a consensus that only the prevalence of acidic and oxidizing aqueous environmental conditions are conducive to form jarosite. In the Kachchh region of Gujarat, western India, jarosite has been recently discovered from gorges dissecting the Paleocene Matanumadh Formation sediments, that overlie basalts of the Deccan Volcanic Province. This formation comprises pebble conglomerates, carbonaceous shales and purple sandstones capped by a laterite on top. Jarosite, in association with gypsum and goethite, has been detected through FTIR and VNIR spectrometry in almost all litho-units of the succession, albeit in different modes and concentrations. The occurrence of jarosite within black shale in other parts of the world, has been attributed to the oxidation of pyrites within the shale layers. However, in shales of the Matanumadh Formation, jarosite is restricted to fractures that cut across the bedding, while the overlying purple sandstone unit only preserves jarosite in shale clasts within the sandstone. Since the sandstone overlies the black shale layer, downward percolation of sulfate-bearing water from the oxidation of pyrite within the shale layer cannot explain jarosite formation in this unit. In addition, no jarosite is observed below or within pyrite-rich lignite bearing sections in other parts of Kachchh. Alternative suggestions, that jarosite developed in the immediate aftermath of Deccan volcanism as surface waters were rendered acidic by interaction with the final phase of volcanic effusives, are also unlikely as on-going studies suggest that jarosite is not restricted to the Matanumadh Formation. The

  16. Acidity of precipitation as influenced by the filtering of atmospheric sulphur and nitrogen compounds - its role in the element balance and effect on soil

    Science.gov (United States)

    Robert Mayer; Bernhard Ulrich

    1976-01-01

    The data presented here are based upon element balance investigations in a beech forest in Central Germany (Ellenberg 1971). Being located in an altitude of about 500 m above sea level with an annual precipitation of about 1000 mm, and an acid soil with loess as the main constituent, the test site represents a typical environment for many Central European forests....

  17. TOWARD A RISK ASSESSMENT OF PERFLUOROALKYL ACIDS

    Science.gov (United States)

    Perfluoroalkyl acids (PFAA) such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS),and fluorotelomer alcoholsare surfactants that have wide applications in industrial and consumer products. Various fluorotelomer alcohols are known to be metabolized to perfluo...

  18. Advantages of using satellite soil moisture estimates over precipitation products to assess regional vegetation water availability and activity

    Science.gov (United States)

    Chen, Tiexi

    2017-04-01

    To improve the understanding of water-vegetation relationships, direct comparative studies assessing the utility of satellite remotely sensed soil moisture, gridded precipitation products, and land surface model output are needed. A case study was investigated for a water-limited, lateral inflow receiving area in northeastern Australia during December 2008 to May 2009. In January 2009, monthly precipitation showed strong positive anomalies, which led to strong positive soil moisture anomalies. The precipitation anomalies disappeared within a month. In contrast, the soil moisture anomalies persisted for months. Positive anomalies of Normalized Difference Vegetation Index (NDVI) appeared in February, in response to water supply, and then persisted for several months. In addition to these temporal characteristics, the spatial patterns of NDVI anomalies were more similar to soil moisture patterns than to those of precipitation and land surface model output. The long memory of soil moisture mainly relates to the presence of clay-rich soils. Modeled soil moisture from four of five global land surface models failed to capture the memory length of soil moisture and all five models failed to present the influence of lateral inflow. This case study indicates that satellite-based soil moisture is a better predictor of vegetation water availability than precipitation in environments having a memory of several months and thus is able to persistently affect vegetation dynamics. These results illustrate the usefulness of satellite remotely sensed soil moisture in ecohydrology studies. This case study has the potential to be used as a benchmark for global land surface model evaluations. The advantages of using satellite remotely sensed soil moisture over gridded precipitation products are mainly expected in lateral-inflow and/or clay-rich regions worldwide.

  19. Analytical studies assessing the association between extreme precipitation or temperature and drinking water-related waterborne infections: a review.

    Science.gov (United States)

    Guzman Herrador, Bernardo R; de Blasio, Birgitte Freiesleben; MacDonald, Emily; Nichols, Gordon; Sudre, Bertrand; Vold, Line; Semenza, Jan C; Nygård, Karin

    2015-03-27

    Determining the role of weather in waterborne infections is a priority public health research issue as climate change is predicted to increase the frequency of extreme precipitation and temperature events. To document the current knowledge on this topic, we performed a literature review of analytical research studies that have combined epidemiological and meteorological data in order to analyze associations between extreme precipitation or temperature and waterborne disease.A search of the databases Ovid MEDLINE, EMBASE, SCOPUS and Web of Science was conducted, using search terms related to waterborne infections and precipitation or temperature. Results were limited to studies published in English between January 2001 and December 2013.Twenty-four articles were included in this review, predominantly from Asia and North-America. Four articles used waterborne outbreaks as study units, while the remaining articles used number of cases of waterborne infections. Results presented in the different articles were heterogeneous. Although most of the studies identified a positive association between increased precipitation or temperature and infection, there were several in which this association was not evidenced. A number of articles also identified an association between decreased precipitation and infections. This highlights the complex relationship between precipitation or temperature driven transmission and waterborne disease. We encourage researchers to conduct studies examining potential effect modifiers, such as the specific type of microorganism, geographical region, season, type of water supply, water source or water treatment, in order to assess how they modulate the relationship between heavy rain events or temperature and waterborne disease. Addressing these gaps is of primary importance in order to identify the areas where action is needed to minimize negative impact of climate change on health in the future.

  20. Assessing the applicability of WRF optimal parameters under the different precipitation simulations in the Greater Beijing Area

    Science.gov (United States)

    Di, Zhenhua; Duan, Qingyun; Wang, Chen; Ye, Aizhong; Miao, Chiyuan; Gong, Wei

    2017-05-01

    Forecasting skills of the complex weather and climate models have been improved by tuning the sensitive parameters that exert the greatest impact on simulated results based on more effective optimization methods. However, whether the optimal parameter values are still work when the model simulation conditions vary, which is a scientific problem deserving of study. In this study, a highly-effective optimization method, adaptive surrogate model-based optimization (ASMO), was firstly used to tune nine sensitive parameters from four physical parameterization schemes of the Weather Research and Forecasting (WRF) model to obtain better summer precipitation forecasting over the Greater Beijing Area in China. Then, to assess the applicability of the optimal parameter values, simulation results from the WRF model with default and optimal parameter values were compared across precipitation events, boundary conditions, spatial scales, and physical processes in the Greater Beijing Area. The summer precipitation events from 6 years were used to calibrate and evaluate the optimal parameter values of WRF model. Three boundary data and two spatial resolutions were adopted to evaluate the superiority of the calibrated optimal parameters to default parameters under the WRF simulations with different boundary conditions and spatial resolutions, respectively. Physical interpretations of the optimal parameters indicating how to improve precipitation simulation results were also examined. All the results showed that the optimal parameters obtained by ASMO are superior to the default parameters for WRF simulations for predicting summer precipitation in the Greater Beijing Area because the optimal parameters are not constrained by specific precipitation events, boundary conditions, and spatial resolutions. The optimal values of the nine parameters were determined from 127 parameter samples using the ASMO method, which showed that the ASMO method is very highly-efficient for optimizing WRF

  1. Assessing potential reasons for different precipitation patterns on Mount Kenya and Kilimanjaro

    Science.gov (United States)

    Covi, Federico; Gohm, Alexander; Kaser, Georg

    2016-04-01

    Mount Kilimanjaro and Mount Kenya in tropical East Africa are often considered as typically influenced by the same air mass. Yet, both precipitation patterns and glacier behavior differ considerably on these neighboring mountains. This indicates that either different air masses are at play or that precipitation processes are considerably different. The present study aims to investigate the most relevant driving mechanism of precipitation over the two neighboring mountains. First, ERA-Interim reanalysis data are used to characterize the atmospheric background conditions of days with precipitation simultaneously recorded on both Kersten Glacier (Kilimanjaro) and Lewis Glacier (Mt Kenya). From this analysis idealized vertical profiles are constructed and used as an atmospheric reference state for simulations with the Weather Research and Forecasting (WRF) model. The semi-realistic model topography is constructed from a high-resolution digital elevation dataset (SRTM). A series of sensitivity simulations is carried out with modified topography, vertical sounding and surface sensible heat flux to asses the dominant factors governing precipitation over the two mountains. With this, we aim to enhance the climate information from the differently behaving glaciers on the two East African mountains.

  2. Glycolic acid physical properties and impurities assessment

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, D. P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pickenheim, B. R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bibler, N. E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hay, M. S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-06-08

    This document has been revised due to recent information that the glycolic acid used in Savannah River National Laboratory (SRNL) experiments contains both formaldehyde and methoxyacetic acid. These impurities were in the glycolic acid used in the testing included in this report and in subsequent testing using DuPont (now called Chemours) supplied Technical Grade 70 wt% glycolic acid. However, these impurities were not reported in earlier revisions. Additional data concerning the properties of glycolic acid have also been added to this report. The Defense Waste Processing Facility (DWPF) is planning to implement a nitric-glycolic acid flowsheets to increase attainment to meet closure commitment dates during Sludge Batch 9. In fiscal year 2009, SRNL was requested to determine the physical properties of formic and glycolic acid blends. Blends of formic acid in glycolic acid were prepared and their physical properties tested. Increasing amounts of glycolic acid led to increases in blend density, viscosity and surface tension as compared to the 90 wt% formic acid that is currently used at DWPF. These increases are small, however, and are not expected to present any difficulties in terms of processing. The effect of sulfur impurities in Technical Grade glycolic acid was studied for its impact on DWPF glass quality. While the glycolic acid specification allows for more sulfate than the current formic acid specification, the ultimate impact is expected to be on the order of 0.033 wt% sulfur in glass. Note that lower sulfur content glycolic acid could likely be procured at some increased cost if deemed necessary. A paper study on the effects of radiation on glycolic acid was performed. The analysis indicates that substitution of glycolic acid for formic acid would not increase the radiolytic production rate of H2 and cause an adverse effect in the Slurry Receipt and Adjustment Tank (SRAT) or Slurry Mix Evaporator (SME) process. It has been cited that glycolic acid

  3. Performance Assessment of Multi-Source Weighted-Ensemble Precipitation (MSWEP Product over India

    Directory of Open Access Journals (Sweden)

    Akhilesh S. Nair

    2017-01-01

    Full Text Available Error characterization is vital for the advancement of precipitation algorithms, the evaluation of numerical model outputs, and their integration in various hydro-meteorological applications. The Tropical Rainfall Measuring Mission (TRMM Multi-satellite Precipitation Analysis (TMPA has been a benchmark for successive Global Precipitation Measurement (GPM based products. This has given way to the evolution of many multi-satellite precipitation products. This study evaluates the performance of the newly released multi-satellite Multi-Source Weighted-Ensemble Precipitation (MSWEP product, whose temporal variability was determined based on several data products including TMPA 3B42 RT. The evaluation was conducted over India with respect to the IMD-gauge-based rainfall for pre-monsoon, monsoon, and post monsoon seasons at daily scale for a 35-year (1979–2013 period. The rainfall climatology is examined over India and over four geographical extents within India known to be subject to uniform rainfall. The performance evaluation of rainfall time series was carried out. In addition to this, the performance of the product over different rainfall classes was evaluated along with the contribution of each class to the total rainfall. Further, seasonal evaluation of the MSWEP products was based on the categorical and volumetric indices from the contingency table. Upon evaluation it was observed that the MSWEP products show large errors in detecting the higher quantiles of rainfall (>75th and > 95th quantiles. The MSWEP precipitation product available at a 0.25° × 0.25° spatial resolution and daily temporal resolution matched well with the daily IMD rainfall over India. Overall results suggest that a suitable region and season-dependent bias correction is essential before its integration in hydrological applications. While the MSWEP was observed to perform well for daily rainfall, it suffered from poor detection capabilities for higher quantiles, making

  4. Projections of Future Precipitation Extremes Over Europe: A Multimodel Assessment of Climate Simulations

    Science.gov (United States)

    Rajczak, Jan; Schär, Christoph

    2017-10-01

    Projections of precipitation and its extremes over the European continent are analyzed in an extensive multimodel ensemble of 12 and 50 km resolution EURO-CORDEX Regional Climate Models (RCMs) forced by RCP2.6, RCP4.5, and RCP8.5 (Representative Concentration Pathway) aerosol and greenhouse gas emission scenarios. A systematic intercomparison with ENSEMBLES RCMs is carried out, such that in total information is provided for an unprecedentedly large data set of 100 RCM simulations. An evaluation finds very reasonable skill for the EURO-CORDEX models in simulating temporal and geographical variations of (mean and heavy) precipitation at both horizontal resolutions. Heavy and extreme precipitation events are projected to intensify across most of Europe throughout the whole year. All considered models agree on a distinct intensification of extremes by often more than +20% in winter and fall and over central and northern Europe. A reduction of rainy days and mean precipitation in summer is simulated by a large majority of models in the Mediterranean area, but intermodel spread between the simulations is large. In central Europe and France during summer, models project decreases in precipitation but more intense heavy and extreme rainfalls. Comparison to previous RCM projections from ENSEMBLES reveals consistency but slight differences in summer, where reductions in southern European precipitation are not as pronounced as previously projected. The projected changes of the European hydrological cycle may have substantial impact on environmental and anthropogenic systems. In particular, the simulations indicate a rising probability of summertime drought in southern Europe and more frequent and intense heavy rainfall across all of Europe.

  5. Glycolic acid physical properties and impurities assessment

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, D. P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Pickenheim, B. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hay, M. S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); BIBLER, N. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-08-09

    This document has been revised to add analytical data for fresh, 1 year old, and 4 year old glycolic acid as recommended in Revision 2 of this document. This was needed to understand the concentration of formaldehyde and methoxyacetic acid, impurities present in the glycolic acid used in Savannah River National Laboratory (SRNL) experiments. Based on this information, the concentration of these impurities did not change during storage. These impurities were in the glycolic acid used in the testing included in this report and in subsequent testing using DuPont (now called Chemours) supplied Technical Grade 70 wt% glycolic acid. However, these impurities were not reported in the first two versions of this report. The Defense Waste Processing Facility (DWPF) is planning to implement a nitric-glycolic acid flowsheets to increase attainment to meet closure commitment dates during Sludge Batch 9. In fiscal year 2009, SRNL was requested to determine the physical properties of formic and glycolic acid blends.

  6. 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.

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

    Directory of Open Access Journals (Sweden)

    Ruijie Hao

    Full Text Available 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.

  8. Seasonality of rotavirus in South Asia: a meta-analysis approach assessing associations with temperature, precipitation, and vegetation index.

    Directory of Open Access Journals (Sweden)

    Jyotsna S Jagai

    Full Text Available Rotavirus infection causes a significant proportion of diarrhea in infants and young children worldwide leading to dehydration, hospitalization, and in some cases death. Rotavirus infection represents a significant burden of disease in developing countries, such as those in South Asia.We conducted a meta-analysis to examine how patterns of rotavirus infection relate to temperature and precipitation in South Asia. Monthly rotavirus data were abstracted from 39 published epidemiological studies and related to monthly aggregated ambient temperature and cumulative precipitation for each study location using linear mixed-effects models. We also considered associations with vegetation index, gathered from remote sensing data. Finally, we assessed whether the relationship varied in tropical climates and humid mid-latitude climates.Overall, as well as in tropical and humid mid-latitude climates, low temperature and precipitation levels are significant predictors of an increased rate of rotaviral diarrhea. A 1°C decrease in monthly ambient temperature and a decrease of 10 mm in precipitation are associated with 1.3% and 0.3% increase above the annual level in rotavirus infections, respectively. When assessing lagged relationships, temperature and precipitation in the previous month remained significant predictors and the association with temperature was stronger in the tropical climate. The same association was seen for vegetation index; a seasonal decline of 0.1 units results in a 3.8% increase in rate of rotavirus.In South Asia the highest rate of rotavirus was seen in the colder, drier months. Meteorological characteristics can be used to better focus and target public health prevention programs.

  9. Response of surface water chemistry to reduced levels of acid precipitation: Comparison of trends in two regions of New York, USA

    Science.gov (United States)

    Burns, Douglas A.; McHale, M.R.; Driscoll, C.T.; Roy, K.M.

    2006-01-01

    In light of recent reductions in sulphur (S) and nitrogen (N) emissions mandated by Title IV of the Clean Air Act Amendments of 1990, temporal trends and trend coherence in precipitation (1984-2001 and 1992-2001) and surface water chemistry (1992-2001) were determined in two of the most acid-sensitive regions of North America, i.e. the Catskill and Adirondack Mountains of New York. Precipitation chemistry data from six sites located near these regions showed decreasing sulphate (SO42-), nitrate (NO3-), and base cation (CB) concentrations and increasing pH during 1984-2001, but few significant trends during 1992-2001. Data from five Catskill streams and 12 Adirondack lakes showed decreasing trends in SO42- concentrations at all sites, and decreasing trends in NO3-, CB, and H+ concentrations and increasing trends in dissolved organic carbon at most sites. In contrast, acid-neutralizing capacity (ANC increased significantly at only about half the Adirondack lakes and in one of the Catskill streams. Flow correction prior to trend analysis did not change any trend directions and had little effect on SO42- trends, but it caused several significant non-flow-corrected trends in NO3- and ANC to become non-significant, suggesting that trend results for flow-sensitive constituents are affected by flow-related climate variation. SO42- concentrations showed high temporal coherence in precipitation, surface waters, and in precipitation-surface water comparisons, reflecting a strong link between S emissions, precipitation SO42- concentrations, and the processes that affect S cycling within these regions. NO3- and H+ concentrations and ANC generally showed weak coherence, especially in surface waters and in precipitation-surface water comparisons, indicating that variation in local-scale processes driven by factors such as climate are affecting trends in acid-base chemistry in these two regions. Copyright ?? 2005 John Wiley & Sons, Ltd.

  10. Decolorization of acid and basic dyes: understanding the metabolic degradation and cell-induced adsorption/precipitation by Escherichia coli.

    Science.gov (United States)

    Cerboneschi, Matteo; Corsi, Massimo; Bianchini, Roberto; Bonanni, Marco; Tegli, Stefania

    2015-10-01

    Escherichia coli strain DH5α was successfully employed in the decolorization of commercial anthraquinone and azo dyes, belonging to the general classes of acid or basic dyes. The bacteria showed an aptitude to survive at different pH values on any dye solution tested, and a rapid decolorization was obtained under aerobic conditions for the whole collection of dyes. A deep investigation about the mode of action of E. coli was carried out to demonstrate that dye decolorization mainly occurred via three different pathways, specifically bacterial induced precipitation, cell wall adsorption, and metabolism, whose weight was correlated with the chemical nature of the dye. In the case of basic azo dyes, an unexpected fast decolorization was observed after just 2-h postinoculation under aerobic conditions, suggesting that metabolism was the main mechanism involved in basic azo dye degradation, as unequivocally demonstrated by mass spectrometric analysis. The reductive cleavage of the azo group by E. coli on basic azo dyes was also further demonstrated by the inhibition of decolorization occurring when glucose was added to the dye solution. Moreover, no residual toxicity was found in the E. coli-treated basic azo dye solutions by performing Daphnia magna acute toxicity assays. The results of the present study demonstrated that E. coli can be simply exploited for its natural metabolic pathways, without applying any recombinant technology. The high versatility and adaptability of this bacterium could encourage its involvement in industrial bioremediation of textile and leather dyeing wastewaters.

  11. Application of MINTEQA2 to the evaluation of apatite as a precipitant for acid mine drainage treatment

    Energy Technology Data Exchange (ETDEWEB)

    Choi, J.C.; West, T.R.; Seol, Y. [Purdue University, West Lafayette, IN (United States). Dept. of Earth and Atmospheric Sciences

    1997-12-31

    The apatite drain system is a new method for acid mine drainage (AMD) treatment. Laboratory tests and field experiments showed that this technique can remove high concentrations of iron and aluminium in AMD having a pH below 4.0 In addition, this system removes both ferric and ferrous iron, whereas a constructed wetlands system removes only ferric iron when converted from the ferrous state in the wetland. A geochemical model, MINTEQA2, was used to simulate the changes in concentration of aqueous constituents, and in the pH and the potential mineral phase. Results of MINTEQA2 support the conclusions of the laboratory and field experiments. Apatite is effective in removing iron, sulfate, and aluminium from AMD; pH was inversely proportional to the flow rate until the equilibrium point was reached (pH = 4.09 at 25{degree}C). Also, the role of apatite as a precipitant and pH buffer was limited by its solubility.

  12. Molecularly imprinted microspheres and nanoparticles prepared using precipitation polymerisation method for selective extraction of gallic acid from Emblica officinalis.

    Science.gov (United States)

    Pardeshi, Sushma; Dhodapkar, Rita; Kumar, Anupama

    2014-03-01

    This paper reports the preparation of gallic acid (GA) molecularly imprinted polymers (MIPs) by the precipitation polymerisation and highlights the effect of porogen on particle size and specific molecular recognition properties. MIP, M-100 prepared in the porogen acetonitrile and MIP, M-75 prepared in a mixture of acetonitrile-toluene (75:25 v/v), resulted in the formation of microspheres with approximately 4μm particle size and surface area of 96.73m(2)g(-1) and nanoparticles (0.8-1000nm) and a surface area of 345.9m(2)g(-1), respectively. The Langmuir-Freundlich isotherm study revealed that M-75 has comparatively higher number of binding sites which are homogenous and has higher affinity for GA. The MIPs selectively recognised GA in presence of its structural analogues. Pure GA with percent recovery of 75 (±1.6) and 83.4 (±2.2) was obtained from the aqueous extract of Emblica officinalis by M-100 and M-75, respectively and hot water at 60°C served as the eluting solvent. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Assessing struvite precipitation in a pilot-scale fluidized bed crystallizer.

    Science.gov (United States)

    Iqbal, M; Bhuiyan, H; Mavinic, D S

    2008-11-01

    The recovery of phosphates from biological wastewater treatment plants, through struvite crystallization, minimizes operational downtime and offers the potential for cost-effective recovery. The pilot-scale, fluidized bed reactor developed at the University of British Columbia (UBC) was found to be effective in recovering phosphate in the form of nearly pure struvite product, from an anaerobic digester centrate. The desired degree of phosphate removal was achieved by maintaining operating pH 8.0-8.2, and recycle ratio 5-9, to control the supersaturation conditions inside the reactor. The performance of the system was found to be optimal when the in-reactor supersaturation ratio was 2-6. In-reactor magnesium to phosphate molar ratio was found to be an important parameter to maintain system performance. In-reactor ammonium to phosphate molar ratio was also found to maintain a good correlation with phosphate removal. The influence of organic ligands on the struvite precipitation was investigated for a small molecular weight organic ligand, acetate, using a chemical equilibrium model PHREEQC. An acetate concentration below about 100 mg l(-1) was not found to affect the precipitation potential of struvite. Calcium and carbonate ion did not have any noticeable effect in struvite crystallization of struvite, under the operational concentrations utilized. Since the precipitation of calcium and carbonate compounds was controlled by kinetic factors, rather than thermodynamic solubility alone, the solid precipitates harvested were pure struvite, with undetectable impurities.

  14. Hydro-metrologic assessment of October 2015 extreme precipitation event on Santee Experimental Forest Watersheds, SC

    Science.gov (United States)

    Devendra M. Amatya; Charles A. Harrison; Carl C. Trettin

    2016-01-01

    The extreme precipitation event on October 3-4, 2015, likely resulting from the convergence of a persistent the terrain, and thecirculation associated with Hurricane Joaquin off the eastern Atlantic Coast(http://cms.met.psu.edu/sref/severe/2015/04Oct2015.pdf) resulted...

  15. Assessment of Mortar Corrosion by Sulphuric Acid

    OpenAIRE

    Kawahigashi, Tatsuo

    2008-01-01

    In order to study the corrosion mechanisms of water-cement system, cement mortar specimens were immersed in the sulphuric acid solution. Over the periods, changes to the roughened surfaces, mass change and neutralization depth were observed. Corrosion of cement mortar progressed through chemical reaction of sulphuric acid and ion transport in mortar. Relations between the environment operation of sulphuric acid and the corrosion (summation of chemical erosion and neutralization depth) of test...

  16. Uncertainty in runoff based on Global Climate Model precipitation and temperature data - Part 1: Assessment of Global Climate Models

    Science.gov (United States)

    McMahon, T. A.; Peel, M. C.; Karoly, D. J.

    2014-05-01

    Two key sources of uncertainty in projections of future runoff for climate change impact assessments are uncertainty between Global Climate Models (GCMs) and within a GCM. Uncertainty between GCM projections of future climate can be assessed through analysis of runs of a given scenario from a wide range of GCMs. Within GCM uncertainty is the variability in GCM output that occurs when running a scenario multiple times but each run has slightly different, but equally plausible, initial conditions. The objective of this, the first of two complementary papers, is to reduce between-GCM uncertainty by identifying and removing poorly performing GCMs prior to the analysis presented in the second paper. Here we assess how well 46 runs from 22 Coupled Model Intercomparison Project phase 3 (CMIP3) GCMs are able to reproduce observed precipitation and temperature climatological statistics. The performance of each GCM in reproducing these statistics was ranked and better performing GCMs identified for later analyses. Observed global land surface precipitation and temperature data were drawn from the CRU 3.10 gridded dataset and re-sampled to the resolution of each GCM for comparison. Observed and GCM based estimates of mean and standard deviation of annual precipitation, mean annual temperature, mean monthly precipitation and temperature and Köppen climate type were compared. The main metrics for assessing GCM performance were the Nash-Sutcliffe efficiency index and RMSE between modelled and observed long-term statistics. This information combined with a literature review of the performance of the CMIP3 models identified the following five models as the better performing models for the next phase of our analysis in assessing the uncertainty in runoff estimated from GCM projections of precipitation and temperature: HadCM3 (Hadley Centre for Climate Prediction and Research), MIROCM (Center for Climate System Research (The University of Tokyo), National Institute for

  17. Assessing the Influence of Precipitation on Diurnal Temperature Range Changes: Implications for Climate Change Projection

    Science.gov (United States)

    Van den Hoof, C.; Garreaud, R.

    2014-12-01

    In this study, we investigate up to what extent the spatial heterogeneity in the projected changes in DTR during the rest of the 21st century (under several emission scenarios) is explained by the regional variability in projected precipitation changes. DTR is indeed a suitable index of climate variability and change [1] and several studies have highlighted the existence of a negative correlation with both the cloud cover and the precipitation rate over land throughout last century [2]. Precipitation reduces DTR mainly by decreasing surface solar radiation through increased cloud cover and by increasing daytime surface evaporative cooling through increased soil moisture content. Whether or not these processes are captured in the current generation of global and regional models is matter of research. To achieve our objective, we make use of the climate projections made available by the CMIP5 project as well as their historical runs, along with reanalysis and station data. At inter-annual timescale, the seasonal mean DTR simulated by an ensemble of CMIP5 models for the last decades shows a negative relationship over land with the simulated precipitation at zero lag. The correlation is globally very strong except during winter at higher latitudes. This corresponds well with the correlations observed in the re-analysis datasets. Some spatial variability in correlation strength is however noticeable between both datasets. Concerning the projected changes, the negative correlation between DTR and precipitation does not hold globally; no correlation or even positive correlations are observed in different climate regions, including Northern South America and Central Europe. Within this study we will further investigate the physical process that could explain this change in correlation sign as well as the reason why positive correlations are rarely observed or simulated at inter-annual timescale under current climate during summer and at lower latitudes during winter. [1] K

  18. Acid precipitation in Canada

    Science.gov (United States)

    P. W. Summers; D. M. Whelpdale

    1976-01-01

    The total annual emissions of sulfur oxides and nitrogen oxides in Canada are estimated to be 7.2 x 106 tons and 1.4 x 106 tons, respectively. These figures represent 5% and 2%, respectively, of the estimated worldwide anthropogenic emissions. Nearly two-thirds of the Canadian SO2 emissions come from...

  19. Assessment of future regional precipitation pattern for an Andes region in Southern Peru

    Science.gov (United States)

    Salzmann, N.; Rohrer, M.; Acuna, D.; Calanca, P.; Huggel, C.

    2012-04-01

    The Cusco and Apurímac region (Southern Peru) in the outer tropical Andes is characterized by a distinct wet and dry season. The climatology of the Andes region in southern Peru is complex and mainly influenced by tropical and extra tropical upper level-large scale circulation as well as by local convection. For the past decades, observations from station data show a slight negative precipitation trend for the area. Scenarios for the future are associated with large uncertainties. Data from the few available Regional Climate Model simulations, and results from statistical downscaling show neither clear nor consistent future precipitation trends for this region The large biodiversity in the high altitude of the Andes and the critical socio-economic situation of the majority of the local population imply a high vulnerability to climate variability and change. Even small shifts in particular in the precipitation regime (sum, frequency or intensity) can therefore have significant impacts on the livelihood of the rural population. Droughts and flooding events that occurred in the past years have demonstrated the heavy repercussion of extreme events. In our study, we analysed and correlated past regional station observations with large-scale circulation patterns from Renanalyses in order to aim at improving our understanding of the major drivers for precipitation in the Cusco-Apurímac region. First results show an only moderate correlation with ENSO and a relative stronger correlation with moisture transported from the Amazon Basin. Our results are then related to large-scale pattern scenarios provided by GCMs and discussed in view of possible impacts of climate change for the Cusco - Apurímac region. In conclusion, we aim at showing at the example of this specific area of the Andes how process knowledge can be used to support the development of adaptation measures in regions with limited availability of data.

  20. Revisiting Pocos de Caldas. Application of the co-precipitation approach to establish realistic solubility limits for performance assessment

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, J.; Duro, L.; Jordana, S.; Cera, E. [QuantiSci, Barcelona (Spain)

    1996-02-01

    Solubility limits constitute a critical parameter for the determination of the mobility of radionuclides in the near field and the geosphere, and consequently for the performance assessment of nuclear waste repositories. Mounting evidence from natural system studies indicate that trace elements, and consequently radionuclides, are associated to the dynamic cycling of major geochemical components. We have recently developed a thermodynamic approach to take into consideration the co-precipitation and co-dissolution processes that mainly control this linkage. The approach has been tested in various natural system studies with encouraging results. The Pocos de Caldas natural analogue was one of the sites where a full testing of our predictive geochemical modelling capabilities were done during the analogue project. We have revisited the Pocos de Caldas data and expanded the trace element solubility calculations by considering the documented trace metal/major ion interactions. This has been done by using the co-precipitation/co-dissolution approach. The outcome is as follows: A satisfactory modelling of the behaviour of U, Zn and REEs is achieved by assuming co-precipitation with ferrihydrite. Strontium concentrations are apparently controlled by its co-dissolution from Sr-rich fluorites. From the performance assessment point of view, the present work indicates that calculated solubility limits using the co-precipitation approach are in close agreement with the actual trace element concentrations. Furthermore, the calculated radionuclide concentrations are 2-4 orders of magnitude lower than conservative solubility limits calculated by assuming equilibrium with individual trace element phases. 34 refs, 18 figs, 13 tabs.

  1. Synthesis of aqueous suspensions of magnetic nanoparticles with the co-precipitation of iron ions in the presence of aspartic acid

    Energy Technology Data Exchange (ETDEWEB)

    Pušnik, Klementina; Goršak, Tanja [Department for Materials Synthesis, Jožef Stefan Institute, 1000 Ljubljana (Slovenia); Jožef Stefan International Postgraduate School, 1000 Ljubljana (Slovenia); Drofenik, Miha [Department for Materials Synthesis, Jožef Stefan Institute, 1000 Ljubljana (Slovenia); Faculty of Chemistry and Chemical Engineering, University of Maribor, 2000 Maribor (Slovenia); Makovec, Darko [Department for Materials Synthesis, Jožef Stefan Institute, 1000 Ljubljana (Slovenia); Jožef Stefan International Postgraduate School, 1000 Ljubljana (Slovenia)

    2016-09-01

    There is increasing demand for the production of large quantities of aqueous suspensions of magnetic iron-oxide nanoparticles. Amino acids are one possible type of inexpensive, nontoxic, and biocompatible molecules that can be used as the surfactants for the preparation of stable suspensions. This preparation can be conducted in a simple, one-step process based on the co-precipitation of Fe{sup 3+}/Fe{sup 2+} ions in the presence of the amino acid. However, the presence of this amino acid changes the mechanism of the magnetic nanoparticles' formation. In this investigation we analyzed the influence of aspartic amino acid (Asp) on the formation of magnetic iron-oxide nanoparticles during the co-precipitation. The process of the nanoparticles’ formation was followed using a combination of TEM, x-ray diffractometry, magnetic measurements, in-situ FT-IR spectroscopy, and chemical analysis, and compared with the formation of nanoparticles without the Asp. The Asp forms a coordination complex with the Fe{sup 3+} ions, which impedes the formation of the intermediate iron oxyhydroxide phase and suppresses the growth of the final magnetic iron-oxide nanoparticles. Slower reaction kinetics can lead to the formation of nonmagnetic secondary phases. The aspartic-acid-absorbed nanoparticles can be dispersed to form relatively concentrated aqueous suspensions displaying a good colloidal stability at an increased pH. - Highlights: • Co-precipitation of Fe{sup 3+}/Fe{sup 2+} ions in the presence of aspartic amino acid (Asp). • Through analysis of nanoparticle formation mechanism. • Presence of Asp changes the mechanism of the nanoparticles’ formation. • Asp forms a coordination complex with the Fe{sup 3+} ions. • Asp impedes the formation of iron oxyhydroxide phase and suppresses the growth of iron-oxide nanoparticles. • The aspartic-acid-absorbed nanoparticles form stable aqueous suspensions.

  2. The precipitation of indium at elevated pH in a stream influenced by acid mine drainage

    Science.gov (United States)

    White, Sarah Jane O.; Hussain, Fatima A.; Hemond, Harold F.; Sacco, Sarah A.; Shine, James P.; Runkel, Robert L.; Walton-Day, Katherine; Kimball, Briant A.

    2017-01-01

    Indium is an increasingly important metal in semiconductors and electronics and has uses in important energy technologies such as photovoltaic cells and light-emitting diodes (LEDs). One significant flux of indium to the environment is from lead, zinc, copper, and tin mining and smelting, but little is known about its aqueous behavior after it is mobilized. In this study, we use Mineral Creek, a headwater stream in southwestern Colorado severely affected by heavy metal contamination as a result of acid mine drainage, as a natural laboratory to study the aqueous behavior of indium. At the existing pH of ~ 3, indium concentrations are 6–29 μg/L (10,000 × those found in natural rivers), and are completely filterable through a 0.45 μm filter. During a pH modification experiment, the pH of the system was raised to > 8, and > 99% of the indium became associated with the suspended solid phase (i.e. does not pass through a 0.45 μm filter). To determine the mechanism of removal of indium from the filterable and likely primarily dissolved phase, we conducted laboratory experiments to determine an upper bound for a sorption constant to iron oxides, and used this, along with other published thermodynamic constants, to model the partitioning of indium in Mineral Creek. Modeling results suggest that the removal of indium from the filterable phase is consistent with precipitation of indium hydroxide from a dissolved phase. This work demonstrates that nonferrous mining processes can be a significant source of indium to the environment, and provides critical information about the aqueous behavior of indium.

  3. Preparation and adsorption properties of molecularly imprinted polymer via RAFT precipitation polymerization for selective removal of aristolochic acid I.

    Science.gov (United States)

    Xiao, Yonghua; Xiao, Rong; Tang, Jian; Zhu, Qiankun; Li, Xiaoming; Xiong, Yan; Wu, Xuewen

    2017-01-01

    The molecularly imprinted polymers (MIP) were prepared via aqueous RAFT precipitation polymerization, with aristolochic acid I (AAI) as the template molecule, AA as the functional monomer, EGDMA as the cross-linker, AIBN as the chain initiator, CTP as the chain transfer agent and 80% (g/g) DMF-aqueous solution as the porogen. The differential UV-vis spectra revealed that a cooperative hydrogen-bonding complex between AAI and AA might be formed at the molar ratio of 1:3 in prepolymerized system. The synthesized MIPs were characterized by FTIR spectra, solid UV-visible absorption spectra, nitrogen adsorption-desorption isotherms and scanning electron microscope, which proved that the MIPs and NIPs have the similar chemical structures and the adding of AAI could affect the size and morphology of the microspheres. UV-visible absorption spectra and High-performance liquid chromatography (HPLC) was used to investigate the adsorption and recognition properties of the MIPs. The Scatchard isotherm model described that the binding sites independently acted. The Langmuir isotherm model suggested an excellent imprinting effect owing to the presence of a large number of specific binding sites on the MIP. The Freundlich model indicated that the AAI could be readily absorbed by MIP. Selective absorption of the template molecule was demonstrated in presence of its analogous compounds, benzoic acid and nitrobenzene. The recycling experiments implied that the MIP could be reused to further selective recognition and separation to AAI for six times at least. MIP was developed for removal of AAI from the Aristolochia manshuriensis extraction. The results indicated that 25mg of MIP could remove the AAI below the HPLC detection limits (6.47ngmL-1) from 5.0mL of the extraction (CAAI=0.0018mgmL-1) with the recovery of AAI to 91.50% (n=3, SD=4.24%). Therefore, it is clearly revealed that the MIP can be a useful tool to remove toxic compounds from natural products. Copyright © 2016 Elsevier

  4. Mathematical modeling of the formation of sedimentary acid precipitation in the atmosphere in view of the evaporation of moisture from their surface

    Directory of Open Access Journals (Sweden)

    Gvozdyakov Dmitry

    2017-01-01

    Full Text Available The article presents the results of numeric simulation of the formation of sedimentary acid precipitation in the atmosphere taking into account the evaporation of moisture from their surfaces. It is established that the joint condensation of vapors of sulfuric anhydride and water vapor, given the flow of solar energy and the evaporation process significantly slows the growth of drops. The possibility of achieving the underlying surface by the formed sediments is analyzed.

  5. Assessment of the relation between atmospheric precipitation and rainwater runoff for various urban surfaces

    Directory of Open Access Journals (Sweden)

    Romaniak Alicja

    2017-03-01

    Full Text Available The relation between the diurnal sum of atmospheric precipitation and the diurnal volume of rainwater runoff from four experimental hardened surfaces was the subject of a pilot study conducted within the area of the Departmental Agro- and Hydrometeorology Observatory in Wrocław. The selection and the structure of the experimental surfaces were preceded with an inventory-taking of the coverage of hardened surfaces within a Wrocław housing estate with high-rise multifamily buildings. That estate was the second location, next to the area of the Observatory, at which the study presented here was conducted. The surfaces included in the experiment were roof surfaces P1 and P2 covered with heat-sealable roll roofing, surface APB made of gravel-filled openwork concrete plates, and tarmac surface AS. The pilot study was conducted during the period from April to November, 2014. During that period, depending on the type of experimental surface, from 81 to 87 days with atmospheric precipitation were analysed. The mean values of the rainwater runoff coefficients for the eightmonth period were 0.77, 0.77, 0.33 and 0.67 for surfaces P1, P2, APB and AS, respectively. The range of variability of mean values of the coefficients of rainwater runoff from the experimental surfaces in a month is presented by the following relation: APB > P1 > AS > P2. The study did not reveal any direct effect of the number of rainfall days in a month on the value of the coefficient of determination describing the correlation between the diurnal sums of precipitation and the diurnal volumes of rainwater runoff.

  6. Stability and assessment of amino acids in parenteral nutrition solutions.

    Science.gov (United States)

    Unger, Nina; Holzgrabe, Ulrike

    2017-08-02

    Sterile amino acid solutions are applied in medical care as part of Total Parenteral Nutrition systems. Typical formulations consist of variable admixtures of essential and non-essential amino acids together with carbohydrates, electrolytes, vitamins, trace element solutions and lipid emulsions. The complexity of these formulations gives rise to stability and compatibility reflections. This review focuses on amino acid stability in pure amino acid solution and name methods of assessment. Incompatibilities of amino acids with the other ingredients are matter of concern in clinical practice and evaluated for relevance. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Synthesis, Comparison, and Optimization of a Humic Acid-Quat10 Polyelectrolyte Complex by Complexation-Precipitation versus Extrusion-Spheronization.

    Science.gov (United States)

    Siyawamwaya, Margaret; Choonara, Yahya E; Kumar, Pradeep; Kondiah, Pierre P D; du Toit, Lisa C; Pillay, Viness

    2017-11-01

    A novel humic acid and polyquaternium-10 polyelectrolyte complex (PEC) was synthesized utilizing two methods and the solubility and permeability of efavirenz (EFV) were established. Complexation-precipitation and extrusion-spheronization were used to synthesize and compare the drug-loaded PECs. The chemical integrity, thermo-mechanical differences, and morphology between the drug-loaded PECs produced by the two methods were assessed by attenuated total reflectance-Fourier transform infrared, differential scanning calorimetry, and SEM. The extent of drug solubilization was determined using the saturation solubility test while the biocompatibility of both PECs was confirmed by cytotoxicity studies on human adenocarcinoma cells (caco2). Bio-relevant media was used for the solubility and permeability analysis of the optimized PEC formulations for accurate assessment of formulation performance. Ritonavir (RTV) was loaded into the optimized formulation to further corroborate the impact of the PEC on the solubility and permeability properties of a poorly soluble and poorly permeable drug. The optimized EFV-loaded PEC and the RTV-loaded PEC exhibited 14.16 ± 2.81% and 4.39 ± 0.57% increase in solubility, respectively. Both PECs were compared to currently marketed formulations. Intestinal permeation results revealed an enhancement of 61.24 ± 6.92% for EFV and 38.78 ± 0.50% for RTV. Although both fabrication methods produced PECs that enhanced the solubility and permeability of the model Biopharmaceutics Classification System Class II and IV drugs, extrusion-spheronization was selected as most optimal based on the higher solubility and permeability improvement and the impact on caco2 cell viability.

  8. Caprylic acid-induced impurity precipitation from protein A capture column elution pool to enable a two-chromatography-step process for monoclonal antibody purification.

    Science.gov (United States)

    Zheng, Ji; Wang, Lu; Twarowska, Barbara; Laino, Sarah; Sparks, Colleen; Smith, Timothy; Russell, Reb; Wang, Michelle

    2015-01-01

    This article presents the use of caprylic acid (CA) to precipitate impurities from the protein A capture column elution pool for the purification of monoclonal antibodies (mAbs) with the objective of developing a two chromatography step antibody purification process. A CA-induced impurity precipitation in the protein A column elution pool was evaluated as an alternative method to polishing chromatography techniques for use in the purification of mAbs. Parameters including pH, CA concentrations, mixing time, mAb concentrations, buffer systems, and incubation temperatures were evaluated on their impacts on the impurity removal, high-molecular weight (HMW) formation and precipitation step yield. Both pH and CA concentration, but not mAb concentrations and buffer systems, are key parameters that can affect host-cell proteins (HCPs) clearance, HMW species, and yield. CA precipitation removes HCPs and some HMW species to the acceptable levels under the optimal conditions. The CA precipitation process is robust at 15-25°C. For all five mAbs tested in this study, the optimal CA concentration range is 0.5-1.0%, while the pH range is from 5.0 to 6.0. A purification process using two chromatography steps (protein A capture column and ion exchange polishing column) in combination with CA-based impurity precipitation step can be used as a robust downstream process for mAb molecules with a broad range of isoelectric points. Residual CA can be effectively removed by the subsequent polishing cation exchange chromatography. © 2015 American Institute of Chemical Engineers.

  9. Skill Assessment of An Hybrid Technique To Estimate Quantitative Precipitation Forecast For Galicia (nw Spain)

    Science.gov (United States)

    Lage, A.; Taboada, J. J.

    Precipitation is the most obvious of the weather elements in its effects on normal life. Numerical weather prediction (NWP) is generally used to produce quantitative precip- itation forecast (QPF) beyond the 1-3 h time frame. These models often fail to predict small-scale variations of rain because of spin-up problems and their coarse spatial and temporal resolution (Antolik, 2000). Moreover, there are some uncertainties about the behaviour of the NWP models in extreme situations (de Bruijn and Brandsma, 2000). Hybrid techniques, combining the benefits of NWP and statistical approaches in a flexible way, are very useful to achieve a good QPF. In this work, a new technique of QPF for Galicia (NW of Spain) is presented. This region has a percentage of rainy days per year greater than 50% with quantities that may cause floods, with human and economical damages. The technique is composed of a NWP model (ARPS) and a statistical downscaling process based on an automated classification scheme of at- mospheric circulation patterns for the Iberian Peninsula (J. Ribalaygua and R. Boren, 1995). Results show that QPF for Galicia is improved using this hybrid technique. [1] Antolik, M.S. 2000 "An Overview of the National Weather Service's centralized statistical quantitative precipitation forecasts". Journal of Hydrology, 239, pp:306- 337. [2] de Bruijn, E.I.F and T. Brandsma "Rainfall prediction for a flooding event in Ireland caused by the remnants of Hurricane Charley". Journal of Hydrology, 239, pp:148-161. [3] Ribalaygua, J. and Boren R. "Clasificación de patrones espaciales de precipitación diaria sobre la España Peninsular". Informes N 3 y 4 del Servicio de Análisis e Investigación del Clima. Instituto Nacional de Meteorología. Madrid. 53 pp.

  10. Precipitation-mediated responses of soil acid buffering capacity to long-term nitrogen addition in a semi-arid grassland

    Science.gov (United States)

    Cai, Jiangping; Luo, Wentao; Liu, Heyong; Feng, Xue; Zhang, Yongyong; Wang, Ruzhen; Xu, Zhuwen; Zhang, Yuge; Jiang, Yong

    2017-12-01

    Atmospheric nitrogen (N) deposition can result in soil acidification and reduce soil acid buffering capacity. However, it remains poorly understood how changes in precipitation regimes with elevated atmospheric N deposition affect soil acidification processes in a water-limited grassland. Here, we conducted a 9-year split-plot experiment with water addition as the main factor and N addition as the second factor. Results showed that soil acid buffering capacity significantly decreased with increased N inputs, mainly due to the decline of soil effective cation exchange capacity (ECEC) and exchangeable basic cations (especially Ca2+), indicating an acceleration of soil acidification status in this steppes. Significant interactive N and water effects were detected on the soil acid buffering capacity. Water addition enhanced the soil ECEC and exchangeable base cations and thus alleviated the decrease of soil acid buffering capacity under N addition. Our findings suggested that precipitation can mitigate the impact of increased N deposition on soil acidification in semi-arid grasslands. This knowledge should be used to improve models predicting soil acidification processes in terrestrial ecosystems under changing environmental conditions.

  11. WRF simulation of a precipitation event over the Tibetan Plateau, China – an assessment using remote sensing and ground observations

    Directory of Open Access Journals (Sweden)

    F. Maussion

    2011-06-01

    Full Text Available Meteorological observations over the Tibetan Plateau (TiP are scarce, and precipitation estimations over this remote region are difficult. The constantly improving capabilities of numerical weather prediction (NWP models offer the opportunity to reduce this problem by providing precipitation fields and other meteorological variables of high spatial and temporal resolution. Longer time periods of years to decades can be simulated by NWP models by successive model runs of shorter periods, which can be described by the term "regional atmospheric reanalysis". In this paper, we assess the Weather Research and Forecasting (WRF models capacity in retrieving rain- and snowfall on the TiP in such a configuration using a nested approach: the simulations are conducted with three nested domains at spatial resolutions of 30, 10, and 2 km. A validation study is carried out for a one-month period with a special focus on one-week (22–28 October 2008, during which strong rain- and snowfall was observed on the TiP. The output of the model in each resolution is compared to the Tropical Rainfall Measuring Mission (TRMM data set for precipitation and to the Moderate Resolution Imaging Spectroradiometer (MODIS data set for snow extent. TRMM and WRF data are then compared to weather-station measurements. Our results suggest an overall improvement from WRF over TRMM with respect to weather-station measurements. Various configurations of the model with different nesting and forcing strategies, as well as physical parameterisation schemes are compared to propose a suitable design for a regional atmospheric reanalysis over the TiP. The WRF model showed good accuracy in simulating snow- and rainfall on the TiP for a one-month simulation period. Our study reveals that there is nothing like an optimal model strategy applicable for the high-altitude TiP, its fringing high-mountain areas of extremely complex topography and the low-altitude land and sea regions from which

  12. Droughts in a warming climate: A global assessment of Standardized precipitation index (SPI) and Reconnaissance drought index (RDI)

    Science.gov (United States)

    Asadi Zarch, Mohammad Amin; Sivakumar, Bellie; Sharma, Ashish

    2015-07-01

    Both drought and aridity indicate imbalance in water availability. While drought is a natural temporal hazard, aridity is a constant climatic feature. This paper investigates the changes in drought characteristics across different aridity zones with and without consideration of potential evapotranspiration (PET), as a means to better assess drought in a warming climate. Two drought indexes are employed: (1) Standardized precipitation index (SPI), which is solely based on precipitation; and (2) Reconnaissance drought index (RDI), which, in addition to precipitation, takes PET into account. The two indexes are first employed to observed precipitation and PET data for the period 1960-2009 from the CRU (Climate Research Unit, University of East Anglia) TS 3.1 database. The results indicate that although all the aridity zones experience both downward and upward drought trends, no significant trend is found over large parts of the zones. However, the agreement between SPI and RDI reduces from the hyper-arid zone on one extreme toward the humid zone on the other. In the three more humid zones (i.e. semi-arid, sub-humid, and humid), the indexes exhibit different trends, with RDI showing more decreasing trends (i.e. becoming drier). While SPI generally shows more drought prone areas than RDI for the pre-1998 period, the opposite is observed for the post-1998 period. Given the known changes to PET in observed records, and also expected increases as global warming intensifies, these results suggest that RDI will be consistently different to the SPI as global warming intensifies. This hypothesis is further tested for historic and future climate projections from the CSIRO (Commonwealth Scientific and Industrial Research Organisation, Australia) Mk3.6 global climate model (GCM), with use of the fifth phase of the Coupled Model Intercomparison Project (CMIP5) and RCP8.5 (Representative Concentration Pathways). In this case, PET is calculated using FAO56-PM model for assessment of

  13. Preparation of ellagic acid molecularly imprinted polymeric microspheres based on distillation-precipitation polymerization for the efficient purification of a crude extract.

    Science.gov (United States)

    Zhang, Hua; Zhao, Shangge; Zhang, Lu; Han, Bo; Yao, Xincheng; Chen, Wen; Hu, Yanli

    2016-08-01

    Molecularly imprinted polymeric microspheres with a high recognition ability toward the template molecule, ellagic acid, were synthesized based on distillation-precipitation polymerization. The as-obtained polymers were characterized by scanning electron microscopy, infrared spectroscopy, and thermogravimetric analysis. Static, dynamic, and selective binding tests were adopted to study the binding properties and the molecular recognition ability of the prepared polymers for ellagic acid. The results indicated that the maximum static adsorption capacity of the prepared polymers toward ellagic acid was 37.07 mg/g and the adsorption equilibrium time was about 100 min when the concentration of ellagic acid was 40 mg/mL. Molecularly imprinted polymeric microspheres were also highly selective toward ellagic acid compared with its analogue quercetin. It was found that the content of ellagic acid in the pomegranate peel extract was enhanced from 23 to 86% after such molecularly imprinted solid-phase extraction process. This work provides an efficient way for effective separation and enrichment of ellagic acid from complex matrix, which is especially valuable in industrial production. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Application of dissolvable layered double hydroxides as sorbent in dispersive solid-phase extraction and extraction by co-precipitation for the determination of aromatic acid anions.

    Science.gov (United States)

    Tang, Sheng; Lee, Hian Kee

    2013-08-06

    Three types of magnesium-aluminum layered double hydroxides were synthesized and employed as solid-phase extraction (SPE) sorbents to extract several aromatic acids (protocatechuic acid, mandelic acid, phthalic acid, benzoic acid, and salicylic acid) from aqueous samples. An interesting feature of these sorbents is that they dissolve when the pH of the solution is lower than 4. Thus, the analyte elution step, as needed in conventional sorbent-based extraction, was obviated by dissolving the sorbent in acid after extraction and separation from the sample solution. The extract was then directly injected into a high-performance liquid chromatography-ultraviolet detection system for analysis. In the key adsorption process, both dispersive SPE and co-precipitation extraction with the sorbents were conducted and experimental parameters such as pH, temperature, and extraction time were optimized. The results showed that both extraction methods provided low limits of detection (0.03-1.47 μg/L) and good linearity (r(2) > 0.9903). The optimized extraction conditions were applied to human urine and sports drink samples. This new and interesting extraction approach was demonstrated to be a fast and efficient procedure for the extraction of organic anions from aqueous samples.

  15. Assessing the Added Value of Dynamical Downscaling Using the Standardized Precipitation Index

    Directory of Open Access Journals (Sweden)

    Jared H. Bowden

    2016-01-01

    Full Text Available In this study, the Standardized Precipitation Index (SPI is used to ascertain the added value of dynamical downscaling over the contiguous United States. WRF is used as a regional climate model (RCM to dynamically downscale reanalysis fields to compare values of SPI over drought timescales that have implications for agriculture and water resources planning. The regional climate generated by WRF has the largest improvement over reanalysis for SPI correlation with observations as the drought timescale increases. This suggests that dynamically downscaled fields may be more reliable than larger-scale fields for water resource applications (e.g., water storage within reservoirs. WRF improves the timing and intensity of moderate to extreme wet and dry periods, even in regions with homogenous terrain. This study also examines changes in SPI from the extreme drought of 1988 and three “drought busting” tropical storms. Each of those events illustrates the importance of using downscaling to resolve the spatial extent of droughts. The analysis of the “drought busting” tropical storms demonstrates that while the impact of these storms on ending prolonged droughts is improved by the RCM relative to the reanalysis, it remains underestimated. These results illustrate the importance and some limitations of using RCMs to project drought.

  16. Preparation of porous carboxymethyl chitosan grafted poly (acrylic acid) superabsorbent by solvent precipitation and its application as a hemostatic wound dressing.

    Science.gov (United States)

    Chen, Yu; Zhang, Yong; Wang, Fengju; Meng, Weiwei; Yang, Xinlin; Li, Peng; Jiang, Jianxin; Tan, Huimin; Zheng, Yongfa

    2016-06-01

    The volume phase transition of a hydrogel initiated by shrinking may result in complex patterns on its surface. Based on this unique property of hydrogel, we have developed a novel solvent precipitation method to prepare a kind of novel superabsorbent polymers with excellent hemostatic properties. A porous carboxymethyl chitosan grafted poly (acrylic acid) (CMCTS-g-PAA) superabsorbent polymer was prepared by precipitating CMCTS-g-PAA hydrogel with ethanol. Its potential application in hemostatic wound dressing was investigated. The results indicate that the modified superabsorbent polymer is non-cytotoxic. It showed a high swelling capacity and better hemostatic performance in the treatments of hemorrhage model of ear artery, arteria cruralis and spleen of the New Zealand white rabbit than the unmodified polymer and other commonly used clinic wound dressings. The hemostatic mechanism of the porous CMCTS-g-PAA polymer was also discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Assessing the roles of temperature, precipitation, and ENSO in dengue re-emergence on the Texas-Mexico border region.

    Science.gov (United States)

    Brunkard, Joan M; Cifuentes, Enrique; Rothenberg, Stephen J

    2008-01-01

    The goal of this study was to assess linkages between microclimate and longer-term ENSO-related weather forcing on the week-to-week changes in dengue prevalence in Matamoros, Tamaulipas, Mexico, over a recent decade of dengue observations. An auto-regressive model to evaluate the role of climatic factors (sea-surface temperature) and weather (maximum temperature, minimum temperature, precipitation) on dengue incidence over the period 1995-2005, was developed by conducting time-series analysis. Dengue incidence increased by 2.6% (95% CI: 0.2-5.1) one week after every 1 degree Celsius increase in weekly maximum temperature and increased 1.9% (95% CI: -0.1-3.9) two weeks after every 1 cm increase in weekly precipitation. Every 1 masculineC increase in sea surface temperatures (El Niño region 3.4 ) was followed by a 19.4% (95% CI: -4.7-43.5) increase in dengue incidence (18 weeks later). Climate and weather factors play a small but significant role in dengue transmission in Matamoros, Mexico. This study may provide baseline information for identifying potential longer-term effects of global climate change on dengue expected in the coming decades. To our knowledge, this is the first study to investigate the potential associations between climate and weather events and dengue incidence in this geographical area.

  18. Assessing Acid-Base Status: Physiologic Versus Physicochemical Approach.

    Science.gov (United States)

    Adrogué, Horacio J; Madias, Nicolaos E

    2016-11-01

    The physiologic approach has long been used in assessing acid-base status. This approach considers acids as hydrogen ion donors and bases as hydrogen ion acceptors and the acid-base status of the organism as reflecting the interaction of net hydrogen ion balance with body buffers. In the physiologic approach, the carbonic acid/bicarbonate buffer pair is used for assessing acid-base status and blood pH is determined by carbonic acid (ie, Paco2) and serum bicarbonate levels. More recently, the physicochemical approach was introduced, which has gained popularity, particularly among intensivists and anesthesiologists. This approach posits that the acid-base status of body fluids is determined by changes in the dissociation of water that are driven by the interplay of 3 independent variables: the sum of strong (fully dissociated) cation concentrations minus the sum of strong anion concentrations (strong ion difference); the total concentration of weak acids; and Paco2. These 3 independent variables mechanistically determine both hydrogen ion concentration and bicarbonate concentration of body fluids, which are considered as dependent variables. Our experience indicates that the average practitioner is familiar with only one of these approaches and knows very little, if any, about the other approach. In the present Acid-Base and Electrolyte Teaching Case, we attempt to bridge this knowledge gap by contrasting the physiologic and physicochemical approaches to assessing acid-base status. We first outline the essential features, advantages, and limitations of each of the 2 approaches and then apply each approach to the same patient presentation. We conclude with our view about the optimal approach. Copyright © 2016 National Kidney Foundation, Inc. All rights reserved.

  19. Effects of experimental acid precipitation and liming on vigor, species abundance, and mineral nutrition of ground vegetation in a Norway spruce stand

    Energy Technology Data Exchange (ETDEWEB)

    Rodenkirchen, H.

    1986-09-01

    The effects of simulated sulfuric acid rain and liming on ground vegetation of a 74-year-old Norway Spruce stand were analysed since summer of 1983. During the first two growing seasons no significant change in species composition had occurred on any plot. The frequently applied acid rain injured some constant moss species, this was reflected by chlorosis, necroses, and reduced average coverage or frequency. Damaged moss segments had decreased Ca-, Mg-, Mn-, Zn- and K-concentrations. Some secondary moss species, however were more tolerant to acid precipitation. Liming with dolomite at the beginning of the experiment improved the Ca- and Mg-nutrition of all investigated species (Thuidium tamariscinum, Oxalis acetosella, spruce seedlings), lowered the intensity of injury by acid rain with mosses, and reduced the Mn- (and Zn-)uptake of the vascular plant species. The combination of liming and irrigation with acid or 'normal' water strongly increased the abundance of the herb Oxalis acetosella. Without liming the same species responded to acid rain with lower Ca- (and Mg-)contents in leaves but no visible foliar damage occurred.

  20. Correlation between precipitation and geographical location of the δ2H values of the fatty acids in milk and bulk milk powder

    Science.gov (United States)

    Ehtesham, E.; Baisden, W. T.; Keller, E. D.; Hayman, A. R.; Van Hale, R.; Frew, R. D.

    2013-06-01

    Hydrogen isotope ratios (δ2H) have become a tool for food traceability and authentication of agricultural products. The principle is that the isotopic composition of the produce is influenced by environmental and biological factors and hence exhibits a spatial differentiation of δ2H. This study investigates the variation in δ2H values of New Zealand milk, both in the bulk powder and individual fatty acids extracted from milk samples from dairy factories across New Zealand. Multivariate statistical analyses were used to test for relationships between δ2H of bulk milk powder, milk fatty acid and geographical location. Milk powder samples from different regions of New Zealand were found to exhibit patterns in isotopic composition similar to the corresponding regional precipitation associated with their origin. A model of δ2H in precipitation was developed based on measurements between 2007 and 2010 at 51 stations across New Zealand (Frew and Van Hale, 2011). The model uses multiple linear regressions to predict daily δ2H from 2 geographic and 5 rain-weighted climate variables from the 5 × 5 km New Zealand Virtual Climate Station Network (VCSN). To approximate collection radius for a drying facility the modelled values were aggregated within a 50 km radius of each dairy factory and compared to observed δ2H values of precipitation and bulk milk powder. Daily δ2H predictions for the period from August to December for the area surrounding the sample collection sites were highly correlated with the δ2H values of bulk milk powder. Therefore the δ2H value of milk fatty acids demonstrates promise as a tool for determining the provenance of milk powders and products where milk powder is an ingredient. Separation of milk powder origin to geographic sub-regions within New Zealand was achieved. Hydrogen isotope measurements could be used to complement traditional tracking systems in verifying point of origin.

  1. Direct analysis for urinary protein with biuret reagent, with use of urine ultrafiltrate blanking: comparison with a manual biuret method involving trichloroacetic acid precipitation.

    Science.gov (United States)

    Eckfeldt, J H; Kershaw, M J; Dahl, I I

    1984-03-01

    We describe a method for measuring urinary protein with a centrifugal analyzer. Biuret reagent is used, and blanking with an ultrafiltrate of urine eliminates interferences from the nonprotein, biuret-positive chromogens in urine. We compare results by this new method with those by a manual method in which trichloroacetic acid precipitation and biuret reagent are used. The new method shows good precision and excellent correlation (r = 0.997) with the manual method. The ease and convenience of this assay should make this a useful method for the routine clinical laboratory.

  2. The effect of using citric or acetic acid on survival of Listeria monocytogenes during fish protein recovery by isoelectric solubilization and precipitation process.

    Science.gov (United States)

    Otto, R A; Beamer, S; Jaczynski, J; Matak, K E

    2011-10-01

    Isoelectric solubilization and precipitation (ISP) is a protein recovery process effective at reducing Listeria innocua, a nonpathogenic bacterium typically used as a surrogate for L. monocytogenes in recovered trout protein. The response of L. monocytogenes to ISP processing was determined and compared to the response of L. innocua. Headed and gutted rainbow trout were inoculated with L. monocytogenes (10.16 log CFU/g), homogenized, and pH-adjusted with granular citric acid (pH 2.0 and 2.5) or glacial acetic acid (pH 3.0 and 3.5). Proteins were solubilized and centrifugation was used to remove insoluble components (skin, insoluble protein, so on). The supernatant was returned to the protein isoelectric point (pH 5.5) with NaOH and centrifuged to remove precipitated protein. Microbial load was enumerated on both growth and selective media; recovery was not significantly different (P > 0.05). Surviving cells from each component (protein, insoluble, and water) were compared to initial inoculum numbers. Significant reductions were detected at all pH (P acid, with a mean log reduction of 3.03 in the combined components, and a 3.53 log reduction in the protein portion. Data were compared to results from a previous study using L. innocua. Significant differences (P acid type. These results demonstrate the variability in resistance between species and indicate that L. innocua is not an appropriate surrogate for L. monocytogenes for ISP processing with organic acids. © 2011 Institute of Food Technologists®

  3. Human plasma-derived immunoglobulin G fractionated by an aqueous two-phase system, caprylic acid precipitation, and membrane chromatography has a high purity level and is free of detectable in vitro thrombogenic activity.

    Science.gov (United States)

    Vargas, M; Segura, Á; Wu, Y-W; Herrera, M; Chou, M-L; Villalta, M; León, G; Burnouf, T

    2015-02-01

    Instituto Clodomiro Picado has developed an immunoglobulin G (IgG) plasma fractionation process combining a polyethylene glycol/phosphate aqueous two-phase system (ATPS), caprylic acid precipitation and anion-exchange membrane chromatography. We evaluated the purity and in vitro thrombogenicity of such IgG, in line with current international requirements. Contributions of the different production steps to reduce thrombogenicity were assessed at 0·2 l-scale, and then the methodology was scaled-up to a 10 l-scale and final products (n = 3) were analysed. Purity, immunoglobulin composition, and subclass distribution were determined by electrophoretic and immunochemical methods. The in vitro thrombogenic potential was determined by a thrombin generation assay (TGA) using a Technothrombin fluorogenic substrate. Prekallikrein activator (PKA), plasmin, factor Xa, thrombin and thrombin-like activities were assessed using S-2302, S-2251, S-2222, S-2238 and S-2288 chromogenic substrates, respectively, and FXI by an ELISA. The thrombogenicity markers were reduced mostly during the ATPS step and were found to segregate mostly into the discarded liquid upper phase. The caprylic acid precipitation eliminated the residual procoagulant activity. The IgG preparations made from the 10 l-batches contained 100% gamma proteins, low residual IgA and undetectable IgM. The IgG subclass distribution was not substantially affected by the process. TGA and amidolytic activities revealed an undetectable in vitro thrombogenic risk and the absence of proteolytic enzymes in the final product. Fractionating human plasma by an ATPS combined with caprylic acid and membrane chromatography resulted in an IgG preparation of high purity and free of a detectable in vitro thrombogenic risk. © 2014 International Society of Blood Transfusion.

  4. Characterization of Precipitation through Copulas and Expert Judgement for Risk Assessment of Infrastructure

    NARCIS (Netherlands)

    Morales Napoles, O.; Paprotny, D.; Worm, D; Abspoel, L; Courage, W

    2017-01-01

    In this paper two methodologies are investigated that contribute to better assessment of risks related to extreme rainfall events. Firstly, one-parameter bivariate copulas are used to analyze rain gauge data in the Netherlands. Out of three models considered, the Gumbel copula, which indicates upper

  5. Preparation of porous carboxymethyl chitosan grafted poly (acrylic acid) superabsorbent by solvent precipitation and its application as a hemostatic wound dressing

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu, E-mail: cylsy@163.com [School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Zhang, Yong [School of Life Science, Beijing Institute of Technology, Beijing 100081 (China); Wang, Fengju [School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Meng, Weiwei; Yang, Xinlin [School of Life Science, Beijing Institute of Technology, Beijing 100081 (China); Li, Peng [School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Jiang, Jianxin [State Key Laboratory of Trauma Burns and Combined Injury, The Third Military Medical University, Chongqing 400042 (China); Tan, Huimin [School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Zheng, Yongfa [Guangdong Fuyang Biotechnology Co., Ltd., Heyuan, Guangdong 517000 (China)

    2016-06-01

    The volume phase transition of a hydrogel initiated by shrinking may result in complex patterns on its surface. Based on this unique property of hydrogel, we have developed a novel solvent precipitation method to prepare a kind of novel superabsorbent polymers with excellent hemostatic properties. A porous carboxymethyl chitosan grafted poly (acrylic acid) (CMCTS-g-PAA) superabsorbent polymer was prepared by precipitating CMCTS-g-PAA hydrogel with ethanol. Its potential application in hemostatic wound dressing was investigated. The results indicate that the modified superabsorbent polymer is non-cytotoxic. It showed a high swelling capacity and better hemostatic performance in the treatments of hemorrhage model of ear artery, arteria cruralis and spleen of the New Zealand white rabbit than the unmodified polymer and other commonly used clinic wound dressings. The hemostatic mechanism of the porous CMCTS-g-PAA polymer was also discussed. - Highlights: • The novel solvent precipitation method was developed to prepare the porous superabsorbent polymer. • The swelling rate was promoted and the harmful residual monomer was leached after modification. • The modified polymer showed good biological safety. • It showed good hemostasis to arterial hemorrhage model of the animal. • The hemostatic mechanism of the modified superabsorbent polymer was discussed.

  6. Augmenting acid with affective details to assess credibility

    Directory of Open Access Journals (Sweden)

    Roland Fleck

    2011-07-01

    Full Text Available There is a need within the criminal justice systems of many countries to create a valid and applicable system of investigative interviewing and credibility assessment. The present study assesses the general validity one such system, called Assessment Criteria Indicative of Deception (ACID. ACID comprises interviewing strategies that facilitate the detection of deception and content criteria that highlight differences in verbal behavior. Sixty university undergraduates performed a staged theft under time pressure and with incentives designed to increase external validity. The participants were interviewed and assessed using the ACID procedure. Half of them were instructed to answer honestly and the other half to deny his/her participation in the theft. Results showed that honest statements were longer, more vividly detailed, and more spontaneously structured than deceptive statements. Also, the addition of affective details as a dependent measure significantly improved the ACID system. Overall, 48 of 60 statements were accurately classified (26 of 30 honest statements and 22 of 30 deceptive statements. The ACID procedure was effective and benefited from the addition of affective details. The strengths and weaknesses of this study are discussed in light of basic research into deception and potential forensic application.

  7. Precipitation of free fatty acids generated by Malassezia - a possible explanation for the positive effects of lithium succinate in seborrhoeic dermatitis.

    Science.gov (United States)

    Mayser, P; Schulz, S

    2016-08-01

    Lithium succinate and gluconate are effective alternative options licensed for the topical treatment of seborrhoeic dermatitis (SD). Their mode of action is not fully elucidated. Minimal inhibitory concentrations against Malassezia (M.) yeasts, which play an important role in SD, are very high. An assay based on the hydrolysis of ethyl octanoate enables us to test the hydrolytic activity of reference strains of the species M. globosa, M. sympodialis and M. furfur solely without interference by fungal growth as the free octanoic acid generated has antifungal activity. In this assay the presence of alkali salts (lithium, sodium and potassium succinate resp.) in concentrations of 2%, 4% and 8% does not influence hydrolytic activity but the availability of the generated free fatty acid in a dose-dependent manner which was analysed by means of high-performance thin layer chromatography and densitometry. This was best effected with the lithium, followed by the sodium and only to a low degree by the potassium salt. As shown by attenuated total reflection Fourier transform infrared spectroscopy the free fatty acid reacted to the respective alkali soap and precipitate from solution. The alkali soaps could not be utilized by the M. spp. as shown in a modified Tween auxanogram and in lack of fungal growth by ethyl oleate in the presence of 8% lithium succinate. The effect of lithium succinate on growth of M. yeasts and presumably in SD can be explained by a precipitation of free fatty acids as alkali soaps limiting their availability for the growth of these lipid-dependent yeasts. © 2016 European Academy of Dermatology and Venereology.

  8. New composite materials prepared by calcium phosphate precipitation in chitosan/collagen/hyaluronic acid sponge cross-linked by EDC/NHS.

    Science.gov (United States)

    Kaczmarek, B; Sionkowska, A; Kozlowska, J; Osyczka, A M

    2018-02-01

    Nowadays, fabrication of composite materials based on biopolymers is a rising field due to potential for bone repair and tissue engineering application. Blending of different biopolymers and incorporation of inorganic particles in the blend can lead to new materials with improved physicochemical properties and biocompatibility. In this work 3D porous structures called scaffolds based on chitosan, collagen and hyaluronic acid were obtained through the lyophilization process. Scaffolds were cross-linked by EDC/NHS. Infrared spectra for the materials were made, the percentage of swelling, scaffolds porosity and density, mechanical parameters, thermal stability were studied. Moreover, the scaffolds were used as matrixes for the calcium phosphate in situ precipitation. SEM images were taken and EDX analysis was carried out for calcium and phosphorous content determination in the scaffold. In addition, the adhesion and proliferation of human osteosarcoma SaOS-2 cells was examined on obtained scaffolds. The results showed that the properties of 3D composites cross-linked by EDC/NHS were altered after the addition of 1, 2 and 5% hyaluronic acid. Mechanical parameters, thermal stability and porosity of scaffolds were improved. Moreover, calcium and phosphorous were found in each kind of scaffold. SEM images showed that the precipitation was homogeneously carried in the whole volume of samples. Attachment of SaOS-2 cells to all modified materials was better compared to unmodified control and proliferation of these cells was markedly increased on scaffolds with precipitated calcium phosphate. Obtained materials can provide the support useful in tissue engineering and regenerative medicine. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Determination of paclitaxel in hyaluronic acid polymeric micelles in rat blood by protein precipitation-micelle breaking method: application to a pharmacokinetic study.

    Science.gov (United States)

    Liu, Yanhua; Sun, Jin; Lian, He; Li, Xin; Cao, Wen; Bai, Liming; Wang, Yongjun; He, Zhonggui

    2013-09-15

    An efficient dissociation of paclitaxel (PTX) from the home-made hyaluronic acid-octadecyl (HA-C18) polymeric micelles formulation in rat blood could not be achieved using previously published PTX analytical methods. So, we intended to develop the micelle-breaking method to determine paclitaxel encapsulated in the HA-C18 polymeric micelles in blood. The pretreatment method of blood samples adopted a simple one-step protein precipitation-micelle breaking process with methanol as micelle-breaking and protein precipitant solvents for complete extraction of PTX from HA-C18 micelles in blood. The micelle breaking efficiency of methanol was as high as 97.7%. Separation was carried out by gradient elution on an Acquity UPLC BEH C18 column with a mobile phase consisting of water (containing 0.1% formic acid) and acetonitrile. A total single run time was as short as 3.0min. Detection was performed by triple-quadrupole mass spectrometry with positive electrospray ionization as source ionization in multiple-reaction monitoring mode at m/z 854.3→286.2 for PTX and m/z 808.5→527.3 for the internal standard, docetaxel. The method demonstrated good linearity at the concentrations ranging from 20 to 10,000ng/mL. The intra- and inter-day relative standard deviations were less than 9.9%. The mean extraction recoveries of PTX and IS were 94.7% and 87.5%, respectively. In summary, the methanol protein precipitation-micelle breaking method could extract PTX completely from the polymeric micelles. Finally, the method was successfully applied to a pharmacokinetic study of the home-made PTX-loaded HA-C18 polymeric micelles and Taxol solution after intravenous administration in rats. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. GLYCOLIC ACID PHYSICAL PROPERTIES, IMPURITIES, AND RADIATION EFFECTS ASSESSMENT

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, D.; Pickenheim, B.; Hay, M.

    2011-06-20

    The Defense Waste Processing Facility (DWPF) is pursuing alternative reductants/flowsheets to increase attainment to meet closure commitment dates. In fiscal year 2009, SRNL evaluated several options and recommended the further assessment of the nitric/formic/glycolic acid flowsheet. SRNL is currently performing testing with this flowsheet to support the DWPF down-select of alternate reductants. As part of the evaluation, SRNL was requested to determine the physical properties of formic and glycolic acid blends. Blends of formic acid in glycolic acid were prepared and their physical properties tested. Increasing amounts of glycolic acid led to increases in blend density, viscosity and surface tension as compared to the 90 wt% formic acid that is currently used at DWPF. These increases are small, however, and are not expected to present any difficulties in terms of processing. The effect of sulfur impurities in technical grade glycolic acid was studied for its impact on DWPF glass quality. While the glycolic acid specification allows for more sulfate than the current formic acid specification, the ultimate impact is expected to be on the order of 0.03 wt% sulfur in glass. Note that lower sulfur content glycolic acid could likely be procured at some increased cost if deemed necessary. A paper study on the effects of radiation on glycolic acid was performed. The analysis indicates that substitution of glycolic acid for formic acid would not increase the radiolytic production rate of H{sub 2} and cause an adverse effect in the SRAT or SME process. It has been cited that glycolic acid solutions that are depleted of O{sub 2} when subjected to large radiation doses produced considerable quantities of a non-diffusive polymeric material. Considering a constant air purge is maintained in the SRAT and the solution is continuously mixed, oxygen depletion seems unlikely, however, if this polymer is formed in the SRAT solution, the rheology of the solution may be affected and

  11. The application of chitosan/collagen/hyaluronic acid sponge cross-linked by dialdehyde starch addition as a matrix for calcium phosphate in situ precipitation.

    Science.gov (United States)

    Kaczmarek, B; Sionkowska, A; Osyczka, A M

    2018-02-01

    Scaffolds based on chitosan, collagen and hyaluronic acid, cross-linked by dialdehyde starch were obtained through the freeze-drying method. The porous structures were used as matrixes for calcium phosphate in situ precipitation. Composites were characterized by different analyses, e.g. infrared spectroscopy, SEM images, porosity, density, and mechanical tests. Moreover, an examination involving the energy dispersive X-ray spectroscopic method was carried out for the calcium and phosphorus ratio determination. In addition, the adhesion and proliferation of human osteosarcoma SaOS-2 cells were examined on the obtained scaffolds. The results showed that the properties of the scaffolds based on chitosan, collagen, and hyaluronic acid can be modified by dialdehyde starch addition. The mechanical parameters (i.e. compressive modulus and maximum compressive force), porosity, and density of the material were improved. Calcium phosphate was deposited in the scaffolds at the Ca/P ratio ∼2. SEM images showed the homogeneous structure, with interconnected pores. The cross-linker addition and an inorganic compound precipitation improved the biocompatibility of the scaffolds. The obtained materials can provide the support required in tissue engineering and regenerative medicine. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. An assessment of the precipitation product of the EC-Earth dataset in the period 1981-2000

    Science.gov (United States)

    Campo, Lorenzo; Silvestro, Francesco; Rudari, Roberto

    2014-05-01

    The increasing availability of Global Circulation Model (GCM) simulations that span historical periods (part or the whole 20th century) created a number of large meteorological variables datasets, with particular reference to the precipitation. Given the complexity of such models and the incertitude about the forcing or the configuration, with reference, for instance, to the astronomical solar radiation time series, or the presence of data assimilation from different sources or, again, the possible coupling with oceanic dynamics, a validation of such datasets becomes fundamental for assessing either the accuracy of the simulation, the meteorological features that the model can reproduce and the differences between different models/simulations. In this work the rainfall product of the EC-Earth model simulation, based on the ECMWF Seasonal Forecasting System, was compared with a global dataset of observed precipitation, CHIRPS. The simulation taken into consideration in this study was open-loop (without assimilation), the simulated period ranging from 1960 to 2012. For this reason only statistical characteristics of the simulated rainfall were considered in the comparison. The CHIRPS dataset is constituted by a merging of satellite-measured rainfall and ground rain gauges network, it covers the period 1981-2012 and it is spatially limited to the band of the land between 50 degrees South Latitude and 50 degrees of North Latitude. The comparison with the EC-Earth rainfall dataset was then limited to this spatial extent and to the period 1981-2000. The analysis was performed both in terms of spatial patterns and differences in the characteristics of the time series on a pixel-per-pixel basis.

  13. Climate change impact assessment of extreme precipitation on urban flash floods – case study, Aarhus, Denmark

    DEFF Research Database (Denmark)

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

    Climate change is expected to cause more intense extreme rainfall events, which will have a severe impact on the risk of flash floods in urban areas. An assessment study was performed for the city of Aarhus, Denmark, analysing different methods of statistical downscaling of climate model...... considered. Urban flooding in Aarhus was simulated with a model that dynamically couples a hydraulic model of the drainage system and a 2D overland flow model. Scenarios representing current and future climate including uncertainties in the climate projections were analysed using synthetic design storms...... projections for estimation of changes in extreme rainfall characteristics. Climate model projections from 20 regional climate models (RCM) from the ENSEMBLES data archive were used in the analysis. Two different estimation methods were applied, using, respectively, a direct estimation of the changes...

  14. Study of molybdenum (VI) complexation and precipitation by zirconium (IV) in strongly acid medium. Application to nuclear spent fuel dissolution; Etude de la complexation et de la precipitation du molybdene (VI) par le zirconium (IV) en milieu tres acide. Application a la dissolution du combustible nucleaire irradie

    Energy Technology Data Exchange (ETDEWEB)

    Esbelin, E

    1999-07-01

    These last years the formation of solid deposits has been observed in the dissolution workshops of the La Hague plant. A sample of the solid was withdrawn for expertise: molybdenum and zirconium are the two major components of the solid, identified as zirconium molybdate. This thesis consisted in the approach of the mechanisms in solution liable to induce precipitate formation. After a bibliographical overview on the chemistry of Mo(VI) in highly acidic solution, this system was studied by absorption spectrophotometry in perchloric medium. The implication of two major forms of Mo(VI) in a dimerization equilibrium was confirmed by this way and by {sup 95}Mo NMR. The principal parameters governing this equilibrium were identified. It is thus shown that the molybdenum dimerization reaction is exothermic. Disturbance of the Mo(VI) system in highly acidic solution by Zr(IV) was also studied. In a restricted experimental field, for which 'conventional' exploitation methodologies had to be adapted to the system, a main complex of stoichiometry 1:1 between Mo(VI) and Zr(IV) was found. The precipitation study of Mo(VI) by Zr(IV) under conditions close to those of the dissolution medium of nuclear spent fuel was undertaken. The main parameters which control precipitation kinetics were identified. The results obtained reveal that precipitation is controlled by a single macroscopic process and therefore can be described by a single equation. The solid obtained is composed of only one phase presenting a Mo:Zr non-stoichiometry when compared to the theoretical formula ZrMo{sub 2}O{sub 7}(OH){sub 2},2H{sub 2}O. At last, on the basis of the research results, a descriptive mechanism of the system is proposed in which intervenes a 1:1 intermediate complex, much more soluble than a probable 2:1 precipitation precursor. (author)

  15. 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.

  16. Comparative Assessment of SDSM, IDW and LARS-WG Models for Simulation and Downscaling of Temperature and Precipitation

    Directory of Open Access Journals (Sweden)

    Z. Dehghan

    2017-01-01

    a stochastic weather generator and it is widely used for the climate change assessment. This model uses the observed daily weather data, to compute a set of parameters for probability distributions of weather variables, which are used to generate synthetic weather time series of arbitrary length by randomly selecting values from the appropriate distributions. In this study, data from the Pars Abad meteorological station, which was used as the data for the baseline period, was also used to predict climate variables. The record of data is 30 years (1971-2000, and the mean temperature and precipitation are 13.7 and 283 mm per year, respectively. The driest month is August, which receives less than 5 mm of rain. Most of the rainfall occurs in April, averaging at 47 mm. July is the warmest month of the year, with an average temperature of 28.9 oC, and January is the coldest, with an average temperature of -2.3 °C. Precipitation differs by 42.8 mm between the driest and wettest months of the year and the average temperature varies by 31.2 °C. Results and Discussion: The calibration and validation results of the SDSM and LARS-WG models in the case of temperature showed that two models have better abilities for temperature simulation in comparison with precipitation data and, in all models, the increasing temperature was observed for most of the warm months. In the case of precipitation, the results of three models have considerable different towards each other and changes intensity of decreasing and increasing precipitation compared to the baseline in IDW model is higher and in LARS-WG model is lower than two other models. But, in case of calculated evapotranspiration, the results of SDSM and IDW models indicate the increasing evapotranspiration in the all months even modest and its maximum value is in last spring and summer. While, calculated evapotranspiration by using LARS-WG model has showed the lower estimation than the baseline period which implies the low ability

  17. Assessment of GPM and TRMM Multi-Satellite Precipitation Products in Streamflow Simulations in a Data-Sparse Mountainous Watershed in Myanmar

    Directory of Open Access Journals (Sweden)

    Fei Yuan

    2017-03-01

    Full Text Available Satellite precipitation products from the Global Precipitation Measurement (GPM mission and its predecessor the Tropical Rainfall Measuring Mission (TRMM are a critical data source for hydrological applications in ungauged basins. This study conducted an initial and early evaluation of the performance of the Integrated Multi-satellite Retrievals for GPM (IMERG final run and the TRMM Multi-satellite Precipitation Analysis 3B42V7 precipitation products, and their feasibility in streamflow simulations in the Chindwin River basin, Myanmar, from April 2014 to December 2015 was also assessed. Results show that, although IMERG and 3B42V7 can potentially capture the spatiotemporal patterns of historical precipitation, the two products contain considerable errors. Compared with 3B42V7, no significant improvements were found in IMERG. Moreover, 3B42V7 outperformed IMERG at daily and monthly scales and in heavy rain detections at four out of five gauges. The large errors in IMERG and 3B42V7 distinctly propagated to streamflow simulations via the Xinanjiang hydrological model, with a significant underestimation of total runoff and high flows. The bias correction of the satellite precipitation effectively improved the streamflow simulations. The 3B42V7-based streamflow simulations performed better than the gauge-based simulations. In general, IMERG and 3B42V7 are feasible for use in streamflow simulations in the study area, although 3B42V7 is better suited than IMERG.

  18. A report on acid precipitation and its effects on fish and wildlife resources in Minnesota and Wisconsin

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — An overview of acid rain in Minnesota and Wisconsin, together with suggestions for further research and contact information for state and federal employees involved...

  19. Assessing non-linear variation of temperature and precipitation for different growth periods of maize and their impacts on phenology in the Midwest of Jilin Province, China

    Science.gov (United States)

    Guo, Enliang; Zhang, Jiquan; Wang, Yongfang; Alu, Si; Wang, Rui; Li, Danjun; Ha, Si

    2017-04-01

    In the past two decades, the regional climate in China has undergone significant change, resulting in crop yield reduction and complete failure. The goal of this study is to detect the variation of temperature and precipitation for different growth periods of maize and assess their impact on phenology. The daily meteorological data in the Midwest of Jilin Province during 1960-2014 were used in the study. The ensemble empirical mode decomposition method was adopted to analyze the non-linear trend and fluctuation in temperature and precipitation, and the sensitivity of the length of the maize growth period to temperature and precipitation was analyzed by the wavelet cross-transformation method. The results show that the trends of temperature and precipitation change are non-linear for different growth periods of maize, and the average temperature in the sowing-jointing stage was different from that in the other growth stages, showing a slight decrease trend, while the variation amplitude of maximum temperature is smaller than that of the minimum temperature. This indicates that the temperature difference between day and night shows a gradually decreasing trend. Precipitation in the growth period also showed a decreasing non-linear trend, while the inter-annual variability with period of quasi-3-year and quasi-6-year dominated the variation of temperature and precipitation. The whole growth period was shortened by 10.7 days, and the sowing date was advanced by approximately 11 days. We also found that there was a significant resonance period among temperature, precipitation, and phenology. Overall, a negative correlation between phenology and temperature is evident, while a positive correlation with precipitation is exhibited. The results illustrate that the climate suitability for maize has reduced over the past decades.

  20. Assessment of Humidity Conditions and Trends Based on Standardized Precipitation Evapotranspiration Index (SEPI Over Different Climatic Regions of Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Ghabaei S

    2017-01-01

    Full Text Available Introduction: Drought is a recurrent feature of climate that caused by deficiency of precipitation over time. Due to the rise in water demand and alarming climate change, recent year’s observer much focus on drought and drought conditions. A multiple types of deficits and relevant temporal scales can be achieved through the construction of a joint indicator that draws on information from multiple sources and will therefore enable better assessment of drought characteristics including return period, persistent and severity. The Standardized Precipitation Evapotranspiration Index (SPEI combines information from precipitation and temperature in the form of water surplus or deficit according to Standardized Precipitation Index (SPI. Rainfall over some regions of Iran during some resent year was below average while mean and maximum temperatures were very high during this period, as was evaporation. This would suggest that drought conditions were worse than in previous recent periods with similarly low rainfall. The main objective of this study is to assess the influences of humidity on the SPEI index and investigate its relation with SPI and Reconnaissance Drought Index (RDI over six different climatic regions in Iran. Materials and Methods: Iran has different climatic conditions which vary from desert in central part to costal wet near the Caspian Sea. In this study the selection of stations was done based on Alijani et al (2008 climatic classification. We chose 11 synoptic stations from six different climatic classes including costal wet (Rasht and Babolsar, semi mountains (Mashhad and Tabriz, mountains (Shiraz and Khoram Abad, semi-arid (Tehran and Semnan, arid (Kerman and Yazd and costal desert (Bandar Abas. The Meteorological datasets for the aforementioned stations were obtained from the Iran Meteorological Organization (IRIMO for the period 1960-2010. The compiled data included average monthly values of precipitation, minimum and maximum air

  1. 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 Men+ and Me-SO4 species in AMW samples. Higher concentration of sulfate species (Me-SO4) than free ion species (Men+, 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 Fe3+-SO42-, SO42-, HSO4-, Al-SO4, MgSO40, and CaSO40 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 SO42- to OH- species during acid to alkaline conditions, respectively. The AMW samples were supersaturated in schwertmannite and goethite, confirmed by the Men+-SO4, Men+-Fe-O-OH, or Men+-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 SO4 tetrahedron bonded with Fe-(oxy)hydroxides and the Men+ sorbed by either SO4 or Fe-(oxy)hydroxides. For samples with lower pH values (pH ~ 2.5-samples SD1 and SD4), the

  2. Photodegradation of Acid Black 1 and Removing Heavy Metals from the Water by an Inorganic Nanocomposite Synthesized via Simple Co-Precipitation Method

    Directory of Open Access Journals (Sweden)

    Marziyeh Mohammadi

    2016-07-01

    Full Text Available In this experimental work, PbS/ZnS/ZnO nanocomposite was synthesized via a simple co-precipitation method. The effect of Zn2+/Pb2+ mole ratio was investigated on the product size and morphology. The products were characterized via scanning electron microscopy to obtain product size and morphology. The optical properties of the nanocomposites were studied by ultra violet-visible spectroscopy. Photocatalytic activity of the product was examine by decomposition of acid black 1 as dye. To investigation of the effect of as synthesized nanocomposite on the water treatment, the influences of the nanocomposite to remove heavy ions was studied by atomic absorption spectroscopy. The results showed that the synthesized nanocomposite has well optical properties, photocatalytic and water treatment activities.

  3. DISSOLUTION OF LANTHANUM FLUORIDE PRECIPITATES

    Science.gov (United States)

    Fries, B.A.

    1959-11-10

    A plutonium separatory ore concentration procedure involving the use of a fluoride type of carrier is presented. An improvement is given in the derivation step in the process for plutonium recovery by carrier precipitation of plutonium values from solution with a lanthanum fluoride carrier precipitate and subsequent derivation from the resulting plutonium bearing carrier precipitate of an aqueous acidic plutonium-containing solution. The carrier precipitate is contacted with a concentrated aqueous solution of potassium carbonate to effect dissolution therein of at least a part of the precipitate, including the plutonium values. Any remaining precipitate is separated from the resulting solution and dissolves in an aqueous solution containing at least 20% by weight of potassium carbonate. The reacting solutions are combined, and an alkali metal hydroxide added to a concentration of at least 2N to precipitate lanthanum hydroxide concomitantly carrying plutonium values.

  4. Effect of sulphur dioxide on precipitation and on the sulphur content and acidity of soils in Alberta, Canada

    Science.gov (United States)

    M. Nyborg; J. Crepin; D. Hocking; J. Baker

    1976-01-01

    Rain and snow in Alberta are seldom acid. The S content of snow is so low that the snow pack gives a deposition of less than 1 kg S/ha, even downwind from large SO2 emission sources. Rainfall contributes at the most 4 kg S/ha yearly near SO2 sources, and only about 1 kg S/ha in clean areas. However, rain intercepted by...

  5. Construction of a high resolution precipitation grid over an alpine catchment for multi-scale performance assessment of gridded daily reference data sets.

    Science.gov (United States)

    Gampe, David; Ludwig, Ralf

    2017-04-01

    Precipitation plays a key role in the hydrological cycle and thus is a crucial variable in the meteo-hydrological modeling chain. Accurate spatial and temporal assessment of precipitation is in this context of utmost importance. Gridded reference data sets for precipitation are also needed to evaluate and bias adjust climate model simulations in order to better represent current regional conditions. Uncertainties in these data sets increase when moving to higher spatial resolution, including small-scale processes, and more complex terrain. In this study a high resolution reference data set with a grid size of 1km is derived from over 150 observation stations over the mountainous Adige catchment ( 12,000 km2), located in Northern Italy with elevations up to 3800 m. This gridded product is then applied to evaluate the performance of state-of-the-art reference data sets which are available at various spatial resolutions ranging from several km to climate model scale at 2°. These global or regional data sets stem either directly from observations or re-analysis simulations, with or without assimilated precipitation, or are based remote sensing approaches. The main objective of this study is to address and quantify uncertainties of these coarser data sets. Additionally, whether they perform acceptable on catchment scale and can be applied for bias correction and model calibration, or if regional high resolution data sets outperform these data sets. Comparison is performed at various spatial resolutions corresponding to those of the applied precipitation data sets. Furthermore, an inter comparison of all of these is conducted at a the coarsest common resolution, where higher resolved data sets are aggregated to the target resolution, allowing for an analysis without penalizing data sets at coarse resolution. Performance assessment of the reference data sets is carried out on daily precipitation statistics for the period 1989 - 2008 using a multitude of indicators.

  6. Assessing the influence of ocean-atmosphere forcing on precipitation and drought characteristics at global and regional scales

    Science.gov (United States)

    Ferguson, Ian Michael

    Previous studies have demonstrated that ocean-atmosphere forcing by anomalous sea surface temperatures (SST) significantly influences large-scale hydroclimatic variability. However, the influence of SST anomalies on the stochastic characteristics of regional precipitation and drought is not well understood. This dissertation investigates the influence of SST forcing on hydroclimatic variability at global and regional scales. An ensemble of 20th century atmospheric general circulation model (AGCM) simulations is used to evaluate the SST-forced signal and chaotic noise components of simulated seasonal precipitation. Temporal variability and trends in signal and potential predictability (signal-to-noise ratio) are shown to be significant over much of the globe, while variability in noise is not significant over most regions. Results suggest that ocean-atmosphere forcing of seasonal precipitation is not stationary; results are discussed in the contexts of seasonal climate prediction and global climate change. The influence of SST anomalies on stochastic characteristics of precipitation and drought is subsequently evaluated using two ensembles of AGCM simulations forced with observed (interannually varying) SST and their climatological annual cycle, respectively. SST anomalies are shown to significantly increase interannual variability of precipitation and persistence of precipitation anomalies throughout the tropics and some midlatitude regions. With respect to drought, SST anomalies are shown to increase the duration and magnitude of drought events over much of the tropics; outside of the tropics SST anomalies contribute a small increase in likelihood of persistent drought events. Coupled (atmosphere-ocean-land) general circulation models (CGCMs) pose a number of applications to drought research. The final portion of this dissertation evaluates precipitation characteristics and ocean-atmosphere coupling in nine state-of-the-art CGCMs. CGCMs are shown to generally

  7. Assessing onset and length of greening period in six vegetation types in Oaxaca, Mexico, using NDVI-precipitation relationships.

    Science.gov (United States)

    Gómez-Mendoza, L; Galicia, L; Cuevas-Fernández, M L; Magaña, V; Gómez, G; Palacio-Prieto, J L

    2008-07-01

    Variations in the normalized vegetation index (NDVI) for the state of Oaxaca, in southern Mexico, were analyzed in terms of precipitation anomalies for the period 1997-2003. Using 10-day averages in NDVI data, obtained from AVHRR satellite information, the response of six types of vegetation to intra-annual and inter-annual fluctuations in precipitation were examined. The onset and temporal evolution of the greening period were studied in terms of precipitation variations through spectral analysis (coherence and phase). The results indicate that extremely dry periods, such as those observed in 1997 and 2001, resulted in low values of NDVI for much of Oaxaca, while good precipitation periods produced a rapid response (20-30 days of delay) from a stressed to a non-stressed condition in most vegetation types. One of these rapid changes occurred during the transition from dry to wet conditions during the summer of 1998. As in many parts of the tropics and subtropics, the NDVI reflects low frequency variations in precipitation on several spatial scales. Even after long dry periods (2001-2002), the various regional vegetation types are capable of recovering when a good rainy season takes place, indicating that vegetation types such as the evergreen forests in the high parts of Oaxaca respond better to rainfall characteristics (timing, amount) than to temperature changes, as is the case in most mid-latitudes. This finding may be relevant to prepare climate change scenarios for forests, where increases in surface temperature and precipitation anomalies are expected.

  8. CONCENTRATION OF Pu USING AN IODATE PRECIPITATE

    Science.gov (United States)

    Fries, B.A.

    1960-02-23

    A method is given for separating plutonium from lanthanum in a lanthanum fluoride carrier precipitation process for the recovery of plutonium values from an aqueous solution. The carrier precipitation process includes the steps of forming a lanthanum fluoride precipi- . tate, thereby carrying plutonium out of solution, metathesizing the fluoride precipitate to a hydroxide precipitate, and then dissolving the hydroxide precipitate in nitric acid. In accordance with the invention, the nitric acid solution, which contains plutonium and lanthanum, is made 0.05 to 0.15 molar in potassium iodate. thereby precipitating plutonium as plutonous iodate and the plutonous iodate is separated from the lanthanum- containing supernatant solution.

  9. Acid-Sulfate Alteration at Gusev Crater and Across Mars: High-SiO2 Residues and Ferric Sulfate Precipitates

    Science.gov (United States)

    Morris, R. V.; Catalano, J. G.; Klingelhoefer, G.; Schroeder, C.; Gellert, R.; Clark, B. C.; Ming, D. W.; Yen, A. S.; Arvidson, R. E.; Cohen, B. A.; hide

    2017-01-01

    The Mars Exploration Rover Spirit ended its mission in Gusev crater on sol 2210 after it had become stuck in a deposit of fined-grained and sulfate rich soil with dust covered solar panels unfavorably pointed toward the sun. Final analysis of remaining data from Spirit's Moessbauer spectrometer (Fe redox and mineralogy) for sols 1529 through 2071 is now complete. We focus here on chemical (APXS) and MB data for targets having high-SiO2 or high-SO3 and process link the targets through mixing and geochemical modelling to an acid-sulfate system centered at Home Plate, which is considered to be a hydrovolcanic complex.

  10. Assessment of multiple daily precipitation statistics in ERA-Interim driven Med-CORDEX and EURO-CORDEX experiments against high resolution observations

    Science.gov (United States)

    Fantini, Adriano; Raffaele, Francesca; Torma, Csaba; Bacer, Sara; Coppola, Erika; Giorgi, Filippo; Ahrens, Bodo; Dubois, Clotilde; Sanchez, Enrique; Verdecchia, Marco

    2016-11-01

    We assess the statistics of different daily precipitation indices in ensembles of Med-CORDEX and EURO-CORDEX experiments at high resolution (grid spacing of 0.11°, or RCM11) and medium resolution (grid spacing of 0.44°, or RCM44) with regional climate models (RCMs) driven by the ERA-Interim reanalysis of observations for the period 1989-2008. The assessment is carried out by comparison with a set of high resolution observation datasets for nine European subregions. The statistics analyzed include quantitative metrics for mean precipitation, daily precipitation probability density functions (PDFs), daily precipitation intensity, frequency, 95th percentile and 95th percentile of dry spell length. We assess an ensemble including all Med-CORDEX and EURO-CORDEX models together and others including the Med-CORDEX and EURO-CORDEX separately. For the All Models ensembles, the RCM11 one shows a remarkable performance in reproducing the spatial patterns and seasonal cycle of mean precipitation over all regions, with a consistent and marked improvement compared to the RCM44 ensemble and the ERA-Interim reanalysis. A good consistency with observations by the RCM11 ensemble (and a substantial improvement compared to RCM44 and ERA-Interim) is found also for the daily precipitation PDFs, mean intensity and, to a lesser extent, the 95th percentile. A general improvement by the RCM11 models is also found when the data are upscaled and intercompared at the 0.44° and 1.5° resolutions. For some regions the RCM11 ensemble overestimates the occurrence of very high intensity events while for one region the models underestimate the occurrence of the most intense extremes. The RCM11 ensemble still shows a general tendency to underestimate the dry day frequency and 95th percentile of dry spell length over wetter regions, with only a marginal improvement compared to the lower resolution models. This indicates that the problem of the excessive production of low precipitation events found

  11. Global observed long-term changes in temperature and precipitation extremes: A review of progress and limitations in IPCC assessments and beyond

    Directory of Open Access Journals (Sweden)

    Lisa V. Alexander

    2016-03-01

    Full Text Available The Intergovernmental Panel on Climate Change (IPCC first attempted a global assessment of long-term changes in temperature and precipitation extremes in its Third Assessment Report in 2001. While data quality and coverage were limited, the report still concluded that heavy precipitation events had increased and that there had been, very likely, a reduction in the frequency of extreme low temperatures and increases in the frequency of extreme high temperatures. That overall assessment had changed little by the time of the IPCC Special Report on Extremes (SREX in 2012 and the IPCC Fifth Assessment Report (AR5 in 2013, but firmer statements could be added and more regional detail was possible. Despite some substantial progress throughout the IPCC Assessments in terms of temperature and precipitation extremes analyses, there remain major gaps particularly regarding data quality and availability, our ability to monitor these events consistently and our ability to apply the complex statistical methods required. Therefore this article focuses on the substantial progress that has taken place in the last decade, in addition to reviewing the new progress since IPCC AR5 while also addressing the challenges that still lie ahead.

  12. Assessment of the large-scale pattern of precipitation in the Yangtze River basin and its possible impact on streamflow

    Science.gov (United States)

    Zhang, Z.; Chen, X.; Xu, C.; Hong, Y.

    2011-12-01

    In recent years, the Yangtze River basin is in a prolonged drought and the ongoing drought in the upper and middle reaches has placed immense pressure on the water resource of upper and mid-lower reaches (see Fig.1). Meanwhile, the Three Gorges Dam (TGD) was raised from 66m to 175m (above sea level) which lead to the situation of water resource becoming more complicated. Therefore, the continuous drought and the TGD have arisen many debates and concerns. Although there are many works about the climate change of Yangtze River and its possible relation to the streamflow, however, more attention has been focused on the floods in the river basin. Only a few studies has been conducted on the subject of streamflow responses to the extremely drought event. Based on the CRU and observed streamflow and precipitation data over 100 years, we analyzed the long-term changes of precipitation pattern in the Yangtze River basin and its impact on steamflow. The patters of precipitation in the upper and mid-lower Yangtze are different and the major differences are as fellows. 1) the maximum monthly precipitation of the lower reaches is detected in June, while that occurs in July in the upper reaches; 2) the precipitation anomalies of the upper and mid-lower reaches always show opposite distribution. But if the precipitation anomalies both in the upper and mid-lower reaches appear similar patterns (both in drought/flood conditions) at the same time, the droughts/floods might make more greatly destroy. Currently continuous drought in the Yangtze River is under the latter condition. Thus, the purpose of this study was focus on the changes of precipitation pattern and its possible impact on the streamflow in the Yangtze River basin. The result will be helpful in improving water resource management in the Yangtze River basin.

  13. Assessment for Melting Temperature Measurement of Nucleic Acid by HRM

    Directory of Open Access Journals (Sweden)

    Jing Wang

    2016-01-01

    Full Text Available High resolution melting (HRM, with a high sensitivity to distinguish the nucleic acid species with small variations, has been widely applied in the mutation scanning, methylation analysis, and genotyping. For the aim of extending HRM for the evaluation of thermal stability of nucleic acid secondary structures on sequence dependence, we investigated effects of the dye of EvaGreen, metal ions, and impurities (such as dNTPs on melting temperature (Tm measurement by HRM. The accuracy of HRM was assessed as compared with UV melting method, and little difference between the two methods was found when the DNA Tm was higher than 40°C. Both insufficiency and excessiveness of EvaGreen were found to give rise to a little bit higher Tm, showing that the proportion of dye should be considered for precise Tm measurement of nucleic acids. Finally, HRM method was also successfully used to measure Tms of DNA triplex, hairpin, and RNA duplex. In conclusion, HRM can be applied in the evaluation of thermal stability of nucleic acid (DNA or RNA or secondary structural elements (even when dNTPs are present.

  14. Is extreme precipitation changing?

    Science.gov (United States)

    Papalexiou, Simon Michael

    2015-04-01

    For most of the scientists climate change is a fact. Climate change implies changes not only on the behavior of the temperature but also on other climatic variables like the precipitation. The question raised in this study is whether or not the annual daily maximum precipitation has changed. In order to evaluate if this question can be answered, several thousands of precipitation records are analyzed from all over the globe. Initially the annual daily maxima time series are carefully formed and sequentially all possible trends are estimated in a moving window framework and for several interannual periods, e.g., from 10 years to 100 years. The aim is to estimate the difference between the percentage of increasing and decreasing trends in the annual daily maximum precipitation and assess if this difference indicates any specific pattern.

  15. Hydrogen isotopes of n-alkanes and n-alkanoic acids as tracers of precipitation in a temperate forest and implications for paleorecords

    Science.gov (United States)

    Freimuth, Erika J.; Diefendorf, Aaron F.; Lowell, Thomas V.

    2017-06-01

    The hydrogen isotopic composition of leaf waxes (δDwax) primarily reflects that of plant source water. Therefore, sedimentary δDwax records are increasingly used to reconstruct the δD of past precipitation (δDp) and to investigate paleohydrologic changes. Such reconstructions rely on estimates of apparent fractionation (εapp) between δDp and the resulting δDwax. However, εapp values are modified by numerous environmental and biological factors during leaf wax production. As a result, εapp can vary widely among plant species and growth forms. This complicates estimation of accurate εapp values and presents a central challenge to quantitative leaf wax paleohydrology. During the 2014 growing season, we examined εapp in the five deciduous angiosperm tree species (Prunus serotina, Acer saccharinum, Quercus rubra, Quercus alba, and Ulmus americana) that dominate the temperate forest at Brown's Lake Bog, Ohio, USA. We sampled individuals of each species at weekly to monthly intervals from March to October and report δD values of n-C29 alkanes (δDn-C29 alkane) and n-C28 alkanoic acids (δDn-C28 acid), as well as xylem (δDxw) and leaf water (δDlw). n-Alkane synthesis was most intense 2-3 weeks after leaf emergence and ceased thereafter, whereas n-alkanoic acid synthesis continued throughout the entire growing season. During bud swell and leaf emergence, δDlw was a primary control on δDn-C29 alkane and δDn-C28 acid values, which stabilized once leaves became fully expanded. Metabolic shifts between young and mature leaves may be an important secondary driver of δDwax changes during leaf development. In mature autumn leaves of all species, the mean εapp for n-C29 alkane (-107‰) was offset by approximately -19‰ from the mean εapp for n-C28 alkanoic acid (-88‰). These results indicate that in temperate settings n-alkanes and n-alkanoic acids from deciduous trees are distinct with respect to their abundance, timing of synthesis, and εapp values.

  16. Assessment of precipitation variability and uncertainty of stream flow in the Hindu Kush Himalayan and Karakoram River basins of Pakistan

    Science.gov (United States)

    Faiz, Muhammad Abrar; Liu, Dong; Fu, Qiang; Wrzesiński, Dariusz; Muneer, Shehakk; Khan, Muhammad Imran; Li, Tianxiao; Cui, Song

    2017-09-01

    The agricultural production system and hydropower production of Pakistan is largely dependent on melting water from the Hindu Kush Himalayan and the Karakoram River basins. Regardless of such significant prominence, a complete evaluation of the prevailing state of hydro-climatic variables is missing. In this context, we examine the precipitation variability and uncertainty of river flows based on diversity indexes and Shannon information entropy theory. The results indicate that the Shannon diversity index presents a clear depiction of precipitation variability on all metrological stations as compared to the Simpson diversity index. The maximum precipitation variability was found at Chilas station as compared to Hunza, Bunji and Gilgit stations. The results also show that the diversity indexes are highly, negatively correlated with standard deviation, and the amount of precipitation is less than 50 mm (dry months). At the decadal scale, the Hunza and Astore stations show higher precipitation evenness as compared to the Skardu, Bunji and Gilgit stations. The uncertainty analysis shows higher entropy value E D = 90% for Indus River gauged at Mangla station. The higher entropy means the greater the chaos of the variables and the lower their certainty. The analysis exhibited that the rivers with high stream flow variability also show low entropy of its distribution and therefore higher stream flow concentration in the annual cycle.

  17. Integrated approach to assessing streamflow and precipitation alterations under environmental change: Application in the Niger River Basin

    Directory of Open Access Journals (Sweden)

    Dagbegnon Clement Sohoulande Djebou

    2015-09-01

    New hydrological insights for the region: Over the period 1961–2012, I conduct a change point analysis of the streamflow and report two sub-periods 1961–1982 and 1983–2012. A comparison of precipitation and streamflow during these two time-slices shows meaningful changes. I describe a Kernel density analysis of streamflow and yield a probabilistic estimate of discharge anomalies along the river. Later, I evaluate seasonal trends of precipitation and streamflow. The analyses bring out critical alterations in time and space. However, these alterations seem to foreshadow critical environmental degradations occurring across the watershed. I consider LAI series derived from MODIS images, then I examine and discuss trends in land-cover dynamics in relation with the patterns in precipitation and streamflow. This late analytical step yields a holistic picture of the ongoing alterations in the Niger River Basin. Finally, I emphasize suggestions, valuable for a comprehensive water resources and environment management.

  18. An assessment of the impact of ATMS and CrIS data assimilation on precipitation prediction over the Tibetan Plateau

    Science.gov (United States)

    Xue, Tong; Xu, Jianjun; Guan, Zhaoyong; Chen, Han-Ching; Chiu, Long S.; Shao, Min

    2017-07-01

    Using the National Oceanic and Atmospheric Administration's Gridpoint Statistical Interpolation data assimilation system and the National Center for Atmospheric Research's Advanced Research Weather Research and Forecasting (WRF-ARW) regional model, the impact of assimilating Advanced Technology Microwave Sounder (ATMS) and Cross-track Infrared Sounder (CrIS) satellite data on precipitation prediction over the Tibetan Plateau in July 2015 was evaluated. Four experiments were designed: a control experiment and three data assimilation experiments with different data sets injected: conventional data only, a combination of conventional and ATMS satellite data, and a combination of conventional and CrIS satellite data. The results showed that the monthly mean of precipitation is shifted northward in the simulations and showed an orographic bias described as an overestimation upwind of the mountains and an underestimation in the south of the rain belt. The rain shadow mainly influenced prediction of the quantity of precipitation, although the main rainfall pattern was well simulated. For the first 24 h and last 24 h of accumulated daily precipitation, the model generally overestimated the amount of precipitation, but it was underestimated in the heavy-rainfall periods of 3-5, 13-16, and 22-25 July. The observed water vapor conveyance from the southeastern Tibetan Plateau was larger than in the model simulations, which induced inaccuracies in the forecast of heavy rain on 3-5 July. The data assimilation experiments, particularly the ATMS assimilation, were closer to the observations for the heavy-rainfall process than the control. Overall, based on the experiments in July 2015, the satellite data assimilation improved to some extent the prediction of the precipitation pattern over the Tibetan Plateau, although the simulation of the rain belt without data assimilation shows the regional shifting.

  19. Evaluation of Antioxidant Ability In Vitro and Bioavailability of trans-Cinnamic Acid Nanoparticle by Liquid Antisolvent Precipitate

    Directory of Open Access Journals (Sweden)

    Wengang Li

    2016-01-01

    Full Text Available TCD is a kind of organic acid that is isolated from cinnamon bark or benzoin. TCD has significant antioxidant activity and is widely used in pharmaceutical, cosmetic, and food additives. But TCD has shortcomings of low bioavailability due to poor water solubility. Therefore, we use ethanol as a solvent, deionized water as antisolvent, and hydroxypropyl methylcellulose (HPMC as the surfactant to prepare TCD nanoparticle powder. The optimum preparation conditions were determined as follows: TCD-ethanol solution concentration was 170 mg/mL, the volume ratio of antisolvent was 4 times that of solvent, and the amount of the surfactant was 0.3% stirred for 10 min by 2500 rpm; TCD nanoparticle with a mean particle size (MPS of 130±12.5 nm is obtained under the optimum conditions. SEM, FT-IR, LC-MS/MS, XRD, and DSC were used to characterize the TCD nanoparticle. The results showed that the chemical structure of TCD nanoparticle was not changed, but the crystallization was significantly reduced. Solubility, dissolution rate, antioxidant activity, the in vitro transdermal penetration, and bioavailability of TCD nanoparticles were all much better than these of the raw TCD. These results suggested that TCD nanoparticle might have potential value to become a new oral or transdermal TCD formulation with high bioavailability.

  20. Theoretical study on the mechanisms of cellulose dissolution and precipitation in the phosphoric acid-acetone process.

    Science.gov (United States)

    Kang, Peng; Qin, Wu; Zheng, Zong-Ming; Dong, Chang-Qing; Yang, Yong-Ping

    2012-11-06

    Phosphoric acid-acetone fractionation was applied to pretreat lignocellulose for production of cellulosic ethanol. Cellulose solubility properties in H(2)O, H(3)PO(4) and CH(3)COCH(3) were simulated. Atomic geometry and electronic properties were computed using density functional theory with local-density approximation. H(3)PO(4) molecule is adsorbed between two cellulose segments, forming four hydrogen bonds with E(B) of -1.61 eV. Density of state for cellulose in H(3)PO(4)-cellulose system delocalizes without obvious peak. E(gap) of 4.46 eV is much smaller than that in other systems. Molecular dynamics simulation indicates that fragments of double glucose rings separate in the cellulose-H(3)PO(4) interaction system. Icy CH(3)COCH(3) addition leads to re-gathering of separated fragments. Reaction energy of cellulose in three solvents is around 3.5 eV, implying that cellulose is chemically stable. Moreover, theoretical results correspond to the experiments we have performed, showing that cellulose dissolves in H(3)PO(4), flocculates after CH(3)COCH(3) addition, and finally becomes more liable to be hydrolyzed into glucoses. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Impact of energetic particle precipitation on stratospheric polar constituents: an assessment using monitoring and assimilation of operational MIPAS data

    Directory of Open Access Journals (Sweden)

    A. Robichaud

    2010-02-01

    Full Text Available In 2003, strong energetic particle precipitation (EPP events occurred producing massive amounts of ionization which affected the polar region significantly perturbing its chemical state down to the middle stratosphere. These events and their effects are generally left unaccounted for in current models of stratospheric chemistry and large differences between observations and models are then noted. In this study, we use a coupled 3-D stratospheric dynamical-chemical model and assimilation system to ingest MIPAS temperature and chemical observations. The goal is to gain further understanding of assimilation and monitoring processes during EPP events and their impacts on the stratospheric polar chemistry. Moreover, we investigate the feasibility of assimilating valid "outlier" observations associated with such events. We use OmF (Observation minus Forecast residuals as they filter out phenomena well reproduced by the model (such as gas phase chemistry, transport, diurnal and seasonal cycles thus revealing a clear trace of the EPP. Inspection of OmF statistics in both passive (without chemical assimilation and active (with chemical assimilation cases altogether provides a powerful diagnostic tool to assess the model and assimilation system. We also show that passive OmF can permit a satisfactory evaluation of the ozone partial column loss due to EPP effects. Results suggest a small but significant loss of 5–6 DU (Dobson Units during an EPP-IE (EPP Indirect Effects event in the Antarctic winter of 2003, and about only 1 DU for the SPE (Solar Proton Event of October/November 2003. Despite large differences between the model and MIPAS chemical observations (NO2, HNO3, CH4 and O3, we demonstrate that a careful assimilation with only gas phase chemistry included in the model (i.e. no provision for EPP and with relaxed quality control nearly eliminated the short-term bias and significantly

  2. The influence of weather conditions on road safety : an assessment of the effect of precipitation and temperature.

    NARCIS (Netherlands)

    Bijleveld, F.D. & Churchill, T.

    2009-01-01

    The influence of changes in extreme weather conditions is often identified as a cause of fluctuations in road safety and the resulting numbers of crashes and casualties. This report focuses on an analysis of the aggregate, accumulated effect of weather conditions (precipitation and temperature) on

  3. Hydro-meteorologic assessment of October 2015 extreme precipitation event on Santee Experimental Forest Watersheds, South Carolina

    Science.gov (United States)

    D.M. Amatya; C.A. Harrison; C.C. Trettin

    2016-01-01

    The extreme precipitation event on October 3-4, 2015, likely resulting from the convergence of a persistent deep easterly flow, the continuous supply of moisture, the terrain, and the circulation associated with Hurricane Joaquin off the eastern Atlantic Coast (http://cms.met.psu. edu/sref/severe/2015/04Oct2015.pdf) resulted in extreme and prolonged flooding in many...

  4. Assessment of probabilistic areal reduction factors of precipitations for the entire French territory with gridded rainfall data.

    Science.gov (United States)

    Fouchier, Catherine; Maire, Alexis; Arnaud, Patrick; Cantet, Philippe; Odry, Jean

    2016-04-01

    The starting point of our study was the availability of maps of rainfall quantiles available for the entire French mainland territory at the spatial resolution of 1 km². These maps display the rainfall amounts estimated for different rainfall durations (from 15 minutes to 72 hours) and different return periods (from 2 years up to 1 000 years). They are provided by a regionalized stochastic hourly point rainfall generator, the SHYREG method which was previously developed by Irstea (Arnaud et al., 2007; Cantet and Arnaud, 2014). Being calibrated independently on numerous raingauges data (with an average density across the country of 1 raingauge per 200 km²), this method suffers from a limitation common to point-process rainfall generators: it can only reproduce point rainfall patterns and has no capacity to generate rainfall fields. It can't hence provide areal rainfall quantiles, the estimation of the latter being however needed for the construction of design rainfall or for the diagnostic of observed events. One means of bridging this gap between our local rainfall quantiles and areal rainfall quantiles is given by the concept of probabilistic areal reduction factors of rainfall (ARF) as defined by Omolayo (1993). This concept enables to estimate areal rainfall of a particular frequency within a certain amount of time from point rainfalls of the same frequency and duration. Assessing such ARF for the whole French territory is of particular interest since it should allow us to compute areal rainfall quantiles, and eventually watershed rainfall quantiles, by using the already available grids of statistical point rainfall of the SHYREG method. Our purpose was then to assess these ARF thanks to long time-series of spatial rainfall data. We have used two sets of rainfall fields: i) hourly rainfall fields from a 10-year reference database of Quantitative Precipitation Estimation (QPE) over France (Tabary et al., 2012), ii) daily rainfall fields resulting from a 53-year

  5. Technology and economic assessment of lactic acid production and uses

    Energy Technology Data Exchange (ETDEWEB)

    Datta, R.; Tsai, S.P.

    1996-03-01

    Lactic acid has been an intermediate-volume specialty chemical (world production {approximately}50,000 tons/yr) used in a wide range of food-processing and industrial applications. Potentially, it can become a very large-volume, commodity-chemical intermediate produced from carbohydrates for feedstocks of biodegradable polymers, oxygenated chemicals, environmentally friendly ``green`` solvents, and other intermediates. In the past, efficient and economical technologies for the recovery and purification of lactic acid from fermentation broths and its conversion to the chemical or polymer intermediates had been the key technology impediments and main process cost centers. Development and deployment of novel separations technologies, such as electrodialysis with bipolar membranes, extractive and catalytic distillations, and chemical conversion, can enable low-cost production with continuous processes in large-scale operations. The emerging technologies can use environmentally sound lactic acid processes to produce environmentally useful products, with attractive process economics. These technology advances and recent product and process commercialization strategies are reviewed and assessed.

  6. Assessment and correction of BCC_CSM's performance in capturing leading modes of summer precipitation over North Asia

    KAUST Repository

    Gong, Zhiqiang

    2017-11-07

    This article examines the ability of Beijing Climate Center Climate System Model (BCC_CSM) in demonstrating the prediction accuracy and the leading modes of the summer precipitation over North Asia (NA). A dynamic-statistic combined approach for improving the prediction accuracy and the prediction of the leading modes of the summer precipitation over NA is proposed. Our results show that the BCC_CSM can capture part of the spatial anomaly features of the first two leading modes of NA summer precipitation. Moreover, BCC_CSM regains relationships such that the first and second mode of the empirical orthogonal function (EOF1 and EOF2) of NA summer precipitation, respectively, corresponds to the development of the El Niño and La Niña conditions in the tropical East Pacific. Nevertheless, BCC_CSM exhibits limited prediction skill over most part of NA and presents a deficiency in reproducing the EOF1\\'s and EOF2\\'s spatial pattern over central NA and EOF2\\'s interannual variability. This can be attributed as the possible reasons why the model is unable to capture the correct relationships among the basic climate elements over the central NA, lacks in its ability to reproduce a consistent zonal atmospheric pattern over NA, and has bias in predicting the relevant Sea Surface Temperature (SST) modes over the tropical Pacific and Indian Ocean regions. Based on the proposed dynamic-statistic combined correction approach, compared with the leading modes of BCC_CSM\\'s original prediction, anomaly correlation coefficients of corrected EOF1/EOF2 with the tropical Indian Ocean SST are improved from 0.18/0.36 to 0.51/0.62. Hence, the proposed correction approach suggests that the BCC_CSM\\'s prediction skill for the summer precipitation prediction over NA and its ability to capture the dominant modes could be certainly improved by choosing proper historical analogue information.

  7. Assessment of GPM-IMERG and Other Precipitation Products against Gauge Data under Different Topographic and Climatic Conditions in Iran: Preliminary Results

    Directory of Open Access Journals (Sweden)

    Ehsan Sharifi

    2016-02-01

    Full Text Available The new generation of weather observatory satellites, namely Global Precipitation Measurement (GPM constellation satellites, is the lead observatory of the 10 highly advanced earth orbiting weather research satellites. Indeed, GPM is the first satellite that has been designed to measure light rain and snowfall, in addition to heavy tropical rainfall. This work compares the final run of the Integrated Multi-satellitE Retrievals for GPM (IMERG product, the post real time of TRMM and Multi-satellite Precipitation Analysis (TMPA-3B42 and the Era-Interim product from the European Centre for Medium Range Weather Forecasts (ECMWF against the Iran Meteorological Organization (IMO daily precipitation measured by the synoptic rain-gauges over four regions with different topography and climate conditions in Iran. Assessment is implemented for a one-year period from March 2014 to February 2015. Overall, in daily scale the results reveal that all three products lead to underestimation but IMERG performs better than other products and underestimates precipitation slightly in all four regions. Based on monthly and seasonal scale, in Guilan all products, in Bushehr and Kermanshah ERA-Interim and in Tehran IMERG and ERA-Interim tend to underestimate. The correlation coefficient between IMERG and the rain-gauge data in daily scale is far superior to that of Era-Interim and TMPA-3B42. On the basis of daily timescale of bias in comparison with the ground data, the IMERG product far outperforms ERA-Interim and 3B42 products. According to the categorical verification technique in this study, IMERG yields better results for detection of precipitation events on the basis of Probability of Detection (POD, Critical Success Index (CSI and False Alarm Ratio (FAR in those areas with stratiform and orographic precipitation, such as Tehran and Kermanshah, compared with other satellite/model data sets. In particular, for heavy precipitation (>15 mm/day, IMERG is superior to

  8. Remote Sensing-Based Assessment of the Variability of Winter and Summer Precipitation in the Pamirs and Their Effects on Hydrology and Hazards Using Harmonic Time Series Analysis

    Directory of Open Access Journals (Sweden)

    Eric Pohl

    2015-07-01

    Full Text Available Moisture supply in the Pamir Mountains of Central Asia significantly determines the hydrological cycle and, as a result, impacts the local communities via hazards or socioeconomic aspects, such as hydropower, agriculture and infrastructure. Scarce and unreliable in situ data prevent an accurate assessment of moisture supply, as well as its temporal and spatial variability in this strongly-heterogeneous environment. On the other hand, a clear understanding of climatic and surface processes is required in order to assess water resources and natural hazards. We propose to evaluate the potential of remote sensing and regional climate model (RCM data to overcome such issues. Difficulties arise for the direct analysis of precipitation if the events are sporadic and when the amounts are low. We hence apply a harmonic time series analysis (HANTS algorithm to derive spatio-temporal precipitation distributions and to determine regional boundaries delimiting areas where winter or summer precipitation dominate moisture supply. We complement the study with remote sensing-based products, such as temperature, snow cover and liquid water equivalent thickness. We find a strong intra- and inter-annual variability of meteorological parameters that result in strongly variable water budget and water mobilization. Climatic variability and its effects on floods and droughts are discussed for three outstanding years. The in-house developed HANTS toolbox is a promising instrument to unravel periodic signals in remote sensing time series, even in complex areas, such as the Pamir.

  9. Rainout assessment: the ACRA system and summaries of simulation results. [Computer systems to estimate threats from precipitation scavenging of radioactive debris clouds from nuclear weapons

    Energy Technology Data Exchange (ETDEWEB)

    Watson, C.W.; Barr, S.; Allenson, R.E.

    1977-09-01

    A generalized, three-dimensional, integrated computer code system was developed to estimate collateral-damage threats from precipitation-scavenging (rainout) of airborne debris-clouds from defensive tactical nuclear engagements. This code system, called ACRA for Atmospheric-Contaminant Rainout Assessment, is based on Monte Carlo statistical simulation methods that allow realistic, unbiased simulations of probabilistic storm, wind, and precipitation fields that determine actual magnitudes and probabilities of rainout threats. Detailed models (or data bases) are included for synoptic-scale storm and wind fields; debris transport and dispersal (with the roles of complex flow fields, time-dependent diffusion, and multidimensional shear effects accounted for automatically); microscopic debris-precipitation interactions and scavenging probabilities; air-to-ground debris transport; local demographic features, for assessing actual threats to populations; and nonlinear effects accumulations from multishot scenarios. We simulated several hundred representative shots for West European scenarios and climates to study single-shot and multishot sensitivities of rainout effects to variations in pertinent physical variables.

  10. Acidic precipitation and forest vegetation

    Science.gov (United States)

    Carl Olof Tamm; Ellis B. Cowling

    1976-01-01

    Most plants can take up nutrients from the atmosphere as well as from the soil solution. This capacity is especially important in natural ecosystems such as forests and bogs where nutrients from other sources are scarce and where fertilization is not a normal management procedure. Trees develop very large canopies of leaves and branches that extend high into the air....

  11. An Initial Assessment of the Surface Reference Technique Applied to Data from the Dual-Frequency Precipitation Radar (DPR) on the GPM Satellite

    Science.gov (United States)

    Meneghini, Robert; Kim, Hyokyung; Liao, Liang; Jones, Jeffrey A.; Kwiatkowski, John M.

    2015-01-01

    It has long been recognized that path-integrated attenuation (PIA) can be used to improve precipitation estimates from high-frequency weather radar data. One approach that provides an estimate of this quantity from airborne or spaceborne radar data is the surface reference technique (SRT), which uses measurements of the surface cross section in the presence and absence of precipitation. Measurements from the dual-frequency precipitation radar (DPR) on the Global Precipitation Measurement (GPM) satellite afford the first opportunity to test the method for spaceborne radar data at Ka band as well as for the Ku-band-Ka-band combination. The study begins by reviewing the basis of the single- and dual-frequency SRT. As the performance of the method is closely tied to the behavior of the normalized radar cross section (NRCS or sigma(0)) of the surface, the statistics of sigma(0) derived from DPR measurements are given as a function of incidence angle and frequency for ocean and land backgrounds over a 1-month period. Several independent estimates of the PIA, formed by means of different surface reference datasets, can be used to test the consistency of the method since, in the absence of error, the estimates should be identical. Along with theoretical considerations, the comparisons provide an initial assessment of the performance of the single- and dual-frequency SRT for the DPR. The study finds that the dual-frequency SRT can provide improvement in the accuracy of path attenuation estimates relative to the single-frequency method, particularly at Ku band.

  12. Formation of stratospheric nitric acid by a hydrated ion cluster reaction: chemical and dynamical effects of energetic particle precipitation on the middle atmosphere

    Science.gov (United States)

    Kvissel, O. K.; Orsolini, Y. J.; Stordal, F.

    2012-04-01

    In order to Improve our understanding of the effects of energetic particle precipitation upon the nitrogen family (NOy) and ozone (O3), we have modelled the chemical and dynamical middle atmosphere response to the introduction of a chemical pathway that produces nitric acid (HNO3) by conversion of dinitrogen pentoxide (N2O5) upon hydrated water clusters H+•(H2O)n. We have used an ensemble of simulations with the National Center for Atmospheric Research (NCAR) Whole-Atmosphere Community Climate Model (WACCM) chemistry-climate model. The introduced chemical pathway alters the internal partitioning of NOy during winter months in both hemispheres, and ultimately triggers statistically significant changes in the climatological distributions of constituents including: i) a cold season production of HNO3 with a corresponding loss of N2O5, and ii) a cold season decrease in NOx/NOy-ratio and an increase of O3, in polar regions. We see an improved seasonal evolution of modelled HNO3 compared to satellite observations from Microwave Limb Sounder (MLS), albeit not enough HNO3 is produced at high altitudes. Through O3 changes, both temperature and dynamics are affected, allowing for complex chemical-dynamical feedbacks beyond the cold season when the introduced pathway is active. Hence, we also find a NOx polar increase in spring-to-summer in the SH, and in spring in the NH. The springtime NOx increase arises from anomalously strong poleward transport associated with a weaker polar vortex. In the southern hemisphere, a statistical significant weakening of the stratospheric jet is altered down to the lower stratosphere, and we argue that it is caused by strengthened planetary waves induced by mid-latitude zonal asymmetries in O3 and short-wave heating.

  13. Assessment of Folic Acid Supplementation in Pregnant Women by Estimation of Serum Levels of Tetrahydrofolic Acid, Dihydrofolate Reductase, and Homocysteine

    Directory of Open Access Journals (Sweden)

    Manisha Naithani

    2016-01-01

    Full Text Available Background. Status of folic acid use in pregnant women of the hilly regions in North India was little known. This study was carried out to assess the folic acid use and estimate folate metabolites in pregnant women of this region. Materials and Methods. This cross-sectional study is comprised of 76 pregnant women, whose folic acid supplementation was assessed by a questionnaire and serum levels of homocysteine, tetrahydrofolic acid (THFA, and dihydrofolate reductase (DHFR were estimated using Enzyme Linked Immunoassays. Results. The study data revealed awareness of folic acid use during pregnancy was present in 46.1% and 23.7% were taking folic acid supplements. The study depicted that there was no statistically significant difference between serum levels of THFA and DHFR in pregnant women with and without folic acid supplements (p=0.790. Hyperhomocysteinemia was present in 15.78% of the participants. Conclusion. Less awareness about folic acid supplementation and low use of folic acid by pregnant women were observed in this region. Sufficient dietary ingestion may suffice for the escalated requirements in pregnancy, but since this cannot be ensured, hence folic acid supplementation should be made as an integral part of education and reproductive health programs for its better metabolic use, growth, and development of fetus.

  14. Assessing aluminium toxicity in streams affected by acid mine drainage.

    Science.gov (United States)

    Waters, A S; Webster-Brown, J G

    2013-01-01

    Acid mine drainage (AMD) has degraded water quality and ecology in streams on the Stockton Plateau, the site of New Zealand's largest open-cast coal mining operation. This has previously been attributed largely to the effects of acidity and elevated aluminium (Al) concentrations. However, the toxicity of dissolved Al is dependent on speciation, which is influenced by pH which affects Al hydrolysis, as well as the concentrations of organic carbon and sulphate which complex Al. Methods for the assessment of the toxic fraction of Al, by chemical analysis and geochemical modelling, have been investigated in selected streams on the Stockton Plateau, where dissolved Al concentrations ranged from 0.034 to 27 mg L(-1). Modelling using PHREEQC indicated that between 0.2 and 85% of the dissolved Al was present as the free ion Al(3+), the most toxic Al species, which dominated in waters of pH = 3.8-4.8. Al-sulphate complexation reduced the Al(3+) concentration at lower pH, while Al-organic and -hydroxide complexes dominated at higher pH. Macroinvertebrate richness in the streams identified an Al(3+) 'threshold' of approximately 0.42 mg/L, above which taxa declined rapidly. Colorimetric 'Aluminon' analysis on unpreserved, unfiltered waters provided a better estimation of Al(3+) concentrations than inductively couple plasma-mass spectrometry (ICP-MS) on filtered, acidified waters. The Aluminon method does not react with particulate Al or strong Al complexes, often registering as little as 53% of the dissolved Al concentration determined by ICP-MS.

  15. Glyphosate and aminomethylphosphonic acid chronic risk assessment for soil biota.

    Science.gov (United States)

    von Mérey, Georg; Manson, Philip S; Mehrsheikh, Akbar; Sutton, Peter; Levine, Steven L

    2016-11-01

    Glyphosate is a broad-spectrum herbicide used widely in agriculture, horticulture, private gardens, and public infrastructure, where it is applied to areas such as roadsides, railway tracks, and parks to control the growth of weeds. The exposure risk from glyphosate and the primary soil metabolite aminomethylphosphonic acid (AMPA) on representative species of earthworms, springtails, and predatory soil mites and the effects on nitrogen-transformation processes by soil microorganisms were assessed under laboratory conditions based on internationally recognized guidelines. For earthworms, the reproductive no-observed-effect concentration (NOEC) was 472.8 mg glyphosate acid equivalent (a.e.)/kg dry soil, which was the highest concentration tested, and 198.1 mg/kg dry soil for AMPA. For predatory mites, the reproductive NOEC was 472.8 mg a.e./kg dry soil for glyphosate and 320 mg/kg dry soil for AMPA, the highest concentrations tested. For springtails, the reproductive NOEC was 472.8 mg a.e./kg dry soil for glyphosate and 315 mg/kg dry soil for AMPA, the highest concentrations tested. Soil nitrogen-transformation processes were unaffected by glyphosate and AMPA at 33.1 mg a.e./kg soil and 160 mg/kg soil, respectively. Comparison of these endpoints with worst-case soil concentrations expected for glyphosate (6.62 mg a.e./kg dry soil) and AMPA (6.18 mg/kg dry soil) for annual applications at the highest annual rate of 4.32 kg a.e./ha indicate very low likelihood of adverse effects on soil biota. Environ Toxicol Chem 2016;35:2742-2752. © 2016 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC. © 2016 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC.

  16. Assessment of extreme quantitative precipitation forecasts and development of regional extreme event thresholds using data from HMT-2006 and COOP observers

    Science.gov (United States)

    Ralph, F.M.; Sukovich, E.; Reynolds, D.; Dettinger, M.; Weagle, S.; Clark, W.; Neiman, P.J.

    2010-01-01

    found that the thresholds for the top 1% and top 0.1%of precipitation events were 7.6 cm (24 h)21 [3.0 in. (24 h)-1] and 14.2 cm (24 h)-1 [5.6 in. (24 h)-1] or greater for the CNRFC and only 5.1 cm (24 h)-1 [2.0 in. (24 h)-1] and 9.4 cm (24 h)-1 [3.7 in. (24 h)-1] for the NWRFC, respectively. Similar analyses for all NWS RFCs showed that the threshold for the top 1% of events varies from;3.8 cm (24 h)-1 [1.5 in. (24 h)-1] in the Colorado Basin River Forecast Center (CBRFC) to~5.1 cm (24 h)-1 [3.0 in. (24 h)-1] in the northern tier of RFCs and;7.6 cm (24 h)-1 [3.0 in. (24 h)-1] in both the southern tier and the CNRFC. It is recommended that NWS QPF performance in the future be assessed for extreme events using these thresholds. ?? 2010 American Meteorological Society.

  17. Assessing College Students' Understanding of Acid Base Chemistry Concepts

    Science.gov (United States)

    Wan, Yanjun Jean

    2014-01-01

    Typically most college curricula include three acid base models: Arrhenius', Bronsted-Lowry's, and Lewis'. Although Lewis' acid base model is generally thought to be the most sophisticated among these three models, and can be further applied in reaction mechanisms, most general chemistry curricula either do not include Lewis' acid base model, or…

  18. Assessment of phosphopeptide enrichment/precipitation method for LC-MS/MS based phosphoproteomic analysis of plant tissue

    DEFF Research Database (Denmark)

    Ye, Juanying; Rudashevskaya, Elena; Hansen, Thomas Aarup

    stardand sample preparation protocols. Here, we combine 3 phosphpeptide enrichment methods (IMAC, TiO2 and Calcium Phosphate Precipitation (CPP)), and apply them to phosphoproteomic analysis of Arabidopsis thaliana plasma membrane preparation. Method Plant plasma membranes were isolated from Arabidopsis...... the phosphopeptides with IMAC, TiO2 enrichment methods prior to LTQ-Orbitrap MS analysis. 100 ug plant plasma membrane protein was used for each enrichment experiment. The data was searched against NCBI database on MASCOT server, and the results were validated by in home bioinformatic software using the A...... (MSA) method was used for phosphopeptide fragmentation. The resulting fragment ion spectra were processed with Proteome Discoverer software (Thermo Electron, Bremen, Germany). Results We first investigated the global phosphorylation profile of plant plasma membrane proteins by enriching...

  19. Performance Assessment of GPS-Sensed Precipitable Water Vapor using IGS Ultra-Rapid Orbits: A Preliminary Study in Thailand

    Directory of Open Access Journals (Sweden)

    Yoon-Soo Choi

    2011-01-01

    Full Text Available Precipitable Water Vapor (PWV is a significant variable used for climate change studies. Currently PWV can be derived from the Global Positioning System (GPS observation in addition to the specific instruments such as Radiosondes (RS, Microwave Radiometers (MWR and Meteorological Satellites. To accurately derive PWV from GPS data, long periods of observation time in conjunction with final orbit data have to be applied in the data processing steps. This final orbit data can be acquired from the International GNSS Service (IGS with 13 days latency, which is not practical in climate change studies or meteorological forecasting. Alternatively, real-time ultra-rapid orbits are more suitable for this application but with lower orbit accuracy. It is therefore interesting to evaluate the impact of using different orbits in the estimation of PWV. In this study, data from permanent GPS base stations in Thailand were processed using Bernese 5.0 software to derive near real-time PWV values. Ultra-rapid orbit data have been introduced in the data processing step with different time windows and compared to that using final orbit data with the 24-hr time window. The results have shown that 1.0 mm and 2.9 mm biases can be achieved using 24-hr and 12-hr time windows, respectively. These results therefore address the potential use of ultra-rapid orbits for a near real-time estimation of PWV.

  20. Drought assessment using a TRMM-derived standardized precipitation index for the upper São Francisco River basin, Brazil.

    Science.gov (United States)

    Santos, Celso Augusto Guimarães; Brasil Neto, Reginaldo Moura; Passos, Jacqueline Sobral de Araújo; da Silva, Richarde Marques

    2017-06-01

    In this work, the use of Tropical Rainfall Measuring Mission (TRMM) rainfall data and the Standardized Precipitation Index (SPI) for monitoring spatial and temporal drought variabilities in the Upper São Francisco River basin is investigated. Thus, the spatiotemporal behavior of droughts and cluster regions with similar behaviors is identified. As a result, the joint analysis of clusters, dendrograms, and the spatial distribution of SPI values proved to be a powerful tool in identifying homogeneous regions. The results showed that the northeast region of the basin has the lowest rainfall indices and the southwest region has the highest rainfall depths, and that the region has well-defined dry and rainy seasons from June to August and November to January, respectively. An analysis of the drought and rain conditions showed that the studied region was homogeneous and well-distributed; however, the quantity of extreme and severe drought events in short-, medium- and long-term analysis was higher than that expected in regions with high rainfall depths, particularly in the south/southwest and southeast areas. Thus, an alternative classification is proposed to characterize the drought, which spatially categorizes the drought type (short-, medium-, and long-term) according to the analyzed drought event type (extreme, severe, moderate, and mild).

  1. PROBABILISTIC HAZARD ASSESSMENT FOR TORNADOES, STRAIGHT-LINE WIND, AND EXTREME PRECIPITATION AT THE SAVANNAH RIVER SITE

    Energy Technology Data Exchange (ETDEWEB)

    Werth, D.; (NOEMAIL), A.; Shine, G.

    2013-12-04

    Recent data sets for three meteorological phenomena with the potential to inflict damage on SRS facilities - tornadoes, straight winds, and heavy precipitation - are analyzed using appropriate statistical techniques to estimate occurrence probabilities for these events in the future. Summaries of the results for DOE-mandated return periods and comparisons to similar calculations performed in 1998 by Weber, et al., are given. Using tornado statistics for the states of Georgia and South Carolina, we calculated the probability per year of any location within a 2⁰ square area surrounding SRS being struck by a tornado (the ‘strike’ probability) and the probability that any point will experience winds above set thresholds. The strike probability was calculated to be 1.15E-3 (1 chance in 870) per year and wind speeds for DOE mandated return periods of 50,000 years, 125,000 years, and 1E+7 years (USDOE, 2012) were estimated to be 136 mph, 151 mph and 221 mph, respectively. In 1998 the strike probability for SRS was estimated to be 3.53 E-4 and the return period wind speeds were 148 mph every 50,000 years and 180 mph every 125,000 years. A 1E+7 year tornado wind speed was not calculated in 1998; however a 3E+6 year wind speed was 260 mph. The lower wind speeds resulting from this most recent analysis are largely due to new data since 1998, and to a lesser degree differences in the models used. By contrast, default tornado wind speeds taken from ANSI/ANS-2.3-2011 are somewhat higher: 161 mph for return periods of 50,000 years, 173 mph every 125,000 years, and 230 mph every 1E+7 years (ANS, 2011). Although the ANS model and the SRS models are very similar, the region defined in ANS 2.3 that encompasses the SRS also includes areas of the Great Plains and lower Midwest, regions with much higher occurrence frequencies of strong tornadoes. The SRS straight wind values associated with various return periods were calculated by fitting existing wind data to a Gumbel

  2. Charisma, volatility and violence: assessing the role of crises of charismatic authority in precipitating incidents of millenarian violence

    Directory of Open Access Journals (Sweden)

    John Walliss

    2006-01-01

    Full Text Available In this article the author develops some of the points he has made elsewhere regarding the role of what may be termed ‘crises of charismatic authority’ in producing volatility or even violence within marginal apocalyptic religious groups. The last quarter of the twentieth century witnessed several incidents where such groups engaged in violent actions against themselves, others in the outside world, or typically both (among them the Peoples Temple in Guayana in 1978, Branch Davidians in Waco, Texas in 1994, Order of the Solar Temple in Switzerland, Quebec and France in 1997, Aum Shirinkyo, Japan in 1995, Movement for the Restoration of the Ten Commandments of God, Uganda in 2000. This notion of ‘crises of charismatic authority’ has in many ways become a central, recurring theme in the author's analysis of these incidents. While accepting that such crises were typically not sufficient in themselves to have precipitated each of the dramatic denouements the author has examined, he has come to the conclusion that they did play a major role in each; such crises played a much more significant role than that played by external opposition in almost all of the cases the author examined (the case of the Branch Davidians being perhaps the exception that proves the rule. In this article, the author discusses what he means by crises of charismatic authority (an important task in itself due to the diverse understandings of ‘charisma’ found within the literature and presents a comparative analysis of some of the ways in which these crises can occur.

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

    OpenAIRE

    Shaowei Ning; Jie Wang; Juliang Jin; Hiroshi Ishidaira

    2016-01-01

    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 precipitati...

  4. Rising Precipitation Extremes across Nepal

    Directory of Open Access Journals (Sweden)

    Ramchandra Karki

    2017-01-01

    Full Text Available As a mountainous country, Nepal is most susceptible to precipitation extremes and related hazards, including severe floods, landslides and droughts that cause huge losses of life and property, impact the Himalayan environment, and hinder the socioeconomic development of the country. Given that the countrywide assessment of such extremes is still lacking, we present a comprehensive picture of prevailing precipitation extremes observed across Nepal. First, we present the spatial distribution of daily extreme precipitation indices as defined by the Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI from 210 stations over the period of 1981–2010. Then, we analyze the temporal changes in the computed extremes from 76 stations, featuring long-term continuous records for the period of 1970–2012, by applying a non-parametric Mann−Kendall test to identify the existence of a trend and Sen’s slope method to calculate the true magnitude of this trend. Further, the local trends in precipitation extremes have been tested for their field significance over the distinct physio-geographical regions of Nepal, such as the lowlands, middle mountains and hills and high mountains in the west (WL, WM and WH, respectively, and likewise, in central (CL, CM and CH and eastern (EL, EM and EH Nepal. Our results suggest that the spatial patterns of high-intensity precipitation extremes are quite different to that of annual or monsoonal precipitation. Lowlands (Terai and Siwaliks that feature relatively low precipitation and less wet days (rainy days are exposed to high-intensity precipitation extremes. Our trend analysis suggests that the pre-monsoonal precipitation is significantly increasing over the lowlands and CH, while monsoonal precipitation is increasing in WM and CH and decreasing in CM, CL and EL. On the other hand, post-monsoonal precipitation is significantly decreasing across all of Nepal while winter precipitation is decreasing

  5. Assessing Land Degradation/Recovery in the African Sahel from Long-Term Earth Observation Based Primary Productivity and Precipitation Relationships

    DEFF Research Database (Denmark)

    Fensholt, Rasmus; Rasmussen, Kjeld; Kaspersen, Per Skougaard

    2013-01-01

    Modeling and Mapping Studies 3rd generation (GIMMS3g)) over the year (ΣNDVI), and the blended EO/rain gauge based data-set for annual precipitation (Climate Prediction Center Merged Analysis of Precipitation, CMAP) results in RUE-estimates which are highly correlated with precipitation, rendering RUE...

  6. Aquatic hazard assessment of a commercial sample of naphthenic acids.

    Science.gov (United States)

    Swigert, James P; Lee, Carol; Wong, Diana C L; White, Russell; Scarlett, Alan G; West, Charles E; Rowland, Steven J

    2015-04-01

    This paper presents chemical composition and aquatic toxicity characteristics of a commercial sample of naphthenic acids (NAs). Naphthenic acids are derived from the refining of petroleum middle distillates and can contribute to refinery effluent toxicity. NAs are also present in oil sands process-affected water (OSPW), but differences in the NAs compositions from these sources precludes using a common aquatic toxicity dataset to represent the aquatic hazards of NAs from both origins. Our chemical characterization of a commercial sample of NAs showed it to contain in order of abundance, 1-ring>2-ring>acyclic>3-ring acids (∼84%). Also present were monoaromatic acids (7%) and non-acids (9%, polyaromatic hydrocarbons and sulfur heterocyclic compounds). While the acyclic acids were only the third most abundant group, the five most abundant individual compounds were identified as C(10-14) n-acids (n-decanoic acid to n-tetradecanoic acid). Aquatic toxicity testing of fish (Pimephales promelas), invertebrate (Daphnia magna), algae (Pseudokirchneriella subcapitata), and bacteria (Vibrio fischeri) showed P. promelas to be the most sensitive species with 96-h LL50=9.0 mg L(-1) (LC50=5.6 mg L(-1)). Acute EL50 values for the other species ranged 24-46 mg L(-1) (EC50 values ranged 20-30 mg L(-1)). Biomimetic extraction via solid-phase-microextraction (BE-SPME) suggested a nonpolar narcosis mode of toxic action for D. magna, P. subcapitata, and V. fischeri. The BE analysis under-predicted fish toxicity, which indicates that a specific mode of action, besides narcosis, may be a factor for fishes. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Assessment for Melting Temperature Measurement of Nucleic Acid by HRM

    National Research Council Canada - National Science Library

    Jing Wang; Xiaoming Pan; Xingguo Liang

    2016-01-01

    High resolution melting (HRM), with a high sensitivity to distinguish the nucleic acid species with small variations, has been widely applied in the mutation scanning, methylation analysis, and genotyping...

  8. Fungal Peptaibiotics: Assessing Potential Meteoritic Amino Acid Contamination

    Science.gov (United States)

    Elsila, J. E.; Callahan, M. P.; Glavin, D. P.; Dworkin, J. P.; Bruckner, H.

    2010-01-01

    The presence of non-protein alpha-dialkyl-amino acids such as alpha-aminoisobutyric acid (alpha-A1B) and isovaline (Iva), which are relatively rare in the terrestrial biosphere, has long been used as an indication of the indigeneity of meteoritic amino acids, however, the discovery of alpha-AIB in peptides producers by a widespread group of filamentous fungi indicates the possibility of a terrestrial biotic source for the alpha-AIB observed in some meteorites. The alpha-AIB-containing peptides produced by these fungi are dubbed peptaibiotics. We measured the molecular distribution and stable carbon and nitrogen isotopic ratios for amino acids found in the total hydrolysates of four biologically synthesized peptaibiotics. We compared these aneasurenetts with those from the CM2 carbonaceous chondrite Murchison and from three Antarctic CR2 carbonaceous chondrites in order to understand the peptaibiotics as a potential source of meteoritic contamination.

  9. Assessment of nanofiltration and reverse osmosis potentialities to recover metals, sulfuric acid, and recycled water from acid gold mining effluent.

    Science.gov (United States)

    Ricci, Bárbara C; Ferreira, Carolina D; Marques, Larissa S; Martins, Sofia S; Amaral, Míriam C S

    This work assessed the potential of nanofiltration (NF) and reverse osmosis (RO) to treat acid streams contaminated with metals, such as effluent from the pressure oxidation process (POX) used in refractory gold ore processing. NF and RO were evaluated in terms of rejections of sulfuric acid and metals. Regarding NF, high sulfuric acid permeation (∼100%), was observed, while metals were retained with high efficiencies (∼90%), whereas RO led to high acid rejections (<88%) when conducted in pH values higher than 1. Thus, sequential use of NF and RO was proved to be a promising treatment for sulfuric acid solutions contaminated by metals, such as POX effluent. In this context, a purified acid stream could be recovered in NF permeate, which could be further concentrated in RO. Recovered acid stream could be reused in the gold ore processing or commercialized. A metal-enriched stream could be also recovered in NF retentate and transferred to a subsequent metal recovery stage. In addition, considering the high acid rejection obtained through the proposed system, RO permeate could be used as recycling water.

  10. Quantitating metabolites in protein precipitated serum using NMR spectroscopy.

    Science.gov (United States)

    Nagana Gowda, G A; Raftery, Daniel

    2014-06-03

    Quantitative NMR-based metabolite profiling is challenged by the deleterious effects of abundant proteins in the intact blood plasma/serum, which underscores the need for alternative approaches. Protein removal by ultrafiltration using low molecular weight cutoff filters thus represents an important step. However, protein precipitation, an alternative and simple approach for protein removal, lacks detailed quantitative assessment for use in NMR based metabolomics. In this study, we have comprehensively evaluated the performance of protein precipitation using methanol, acetonitrile, perchloric acid, and trichloroacetic acid and ultrafiltration approaches using 1D and 2D NMR, based on the identification and absolute quantitation of 44 human blood metabolites, including a few identified for the first time in the NMR spectra of human serum. We also investigated the use of a "smart isotope tag," (15)N-cholamine for further resolution enhancement, which resulted in the detection of a number of additional metabolites. (1)H NMR of both protein precipitated and ultrafiltered serum detected all 44 metabolites with comparable reproducibility (average CV, 3.7% for precipitation; 3.6% for filtration). However, nearly half of the quantified metabolites in ultrafiltered serum exhibited 10-74% lower concentrations; specifically, tryptophan, benzoate, and 2-oxoisocaproate showed much lower concentrations compared to protein precipitated serum. These results indicate that protein precipitation using methanol offers a reliable approach for routine NMR-based metabolomics of human blood serum/plasma and should be considered as an alternative to ultrafiltration. Importantly, protein precipitation, which is commonly used by mass spectrometry (MS), promises avenues for direct comparison and correlation of metabolite data obtained from the two analytical platforms to exploit their combined strength in the metabolomics of blood.

  11. Review and assessment of technologies for the separation of strontium from alkaline and acidic media

    Energy Technology Data Exchange (ETDEWEB)

    Orth, R.J.; Kurath, D.E.

    1994-01-01

    A literature survey has been conducted to identify and evaluate methods for the separation of strontium from acidic and alkaline media as applied to Hanford tank waste. The most promising methods of solvent extraction, precipitation, and ion exchange are described. The following criteria were used for evaluating the separation methods: Appreciable strontium removal must be demonstrated; Strontium selectivity over bulk components must be demonstrated; The method must show promise for evolving into a practical and fairly simple process; The process should be safe to operate; The method must be robust (i.e., capable of separating strontium from various waste types); Secondary waste generation must be minimized; and The method must show resistance to radiation damage. The methods discussed did not necessarily satisfy all of the above criteria; thus, key areas requiring further development are also given for each method. Less promising solvent extraction, precipitation, and ion exchange methods were also identified; areas for potential development are included in this report.

  12. An operational procedure for precipitable and cloud liquid water estimate in non-raining conditions over sea Study on the assessment of the nonlinear physical inversion algorithm

    CERN Document Server

    Nativi, S; Mazzetti, P

    2004-01-01

    In a previous work, an operative procedure to estimate precipitable and liquid water in non-raining conditions over sea was developed and assessed. The procedure is based on a fast non-linear physical inversion scheme and a forward model; it is valid for most of satellite microwave radiometers and it also estimates water effective profiles. This paper presents two improvements of the procedure: first, a refinement to provide modularity of the software components and portability across different computation system architectures; second, the adoption of the CERN MINUIT minimisation package, which addresses the problem of global minimisation but is computationally more demanding. Together with the increased computational performance that allowed to impose stricter requirements on the quality of fit, these refinements improved fitting precision and reliability, and allowed to relax the requirements on the initial guesses for the model parameters. The re-analysis of the same data-set considered in the previous pap...

  13. Analysis of trifluoroacetic acid and other short-chain perfluorinated acids (C2-C4) in precipitation by liquid chromatography-tandem mass spectrometry: comparison to patterns of long-chain perfluorinated acids (C5-C18).

    Science.gov (United States)

    Taniyasu, Sachi; Kannan, Kurunthachalam; Yeung, Leo W Y; Kwok, Karen Y; Lam, Paul K S; Yamashita, Nobuyoshi

    2008-07-07

    A method has been developed to measure 29 perfluorinated acids (PFAs) including short-chain perfluorocarboxylates (PFCAs) such as trifluoroacetic acid (TFA; C2) and long-chain PFCAs, perfluoroalkylsulfonates, fluorotelomer acids, and two perfluorooctylsulfonamides in water matrices. The method involves solid phase extraction (SPE) using a weak anion-exchange (WAX) cartridge, an ion-exchange high-performance liquid chromatography (HPLC) column separation, and tandem mass spectrometry (MS/MS) detection. To our knowledge, this is the first HPLC-MS/MS method to determine TFA in water at sub-ng L(-1) concentrations. The method is selective, simple, and robust, capable of measuring 29 PFAs in a single analysis, with overall recoveries of the target analytes ranging from 75% to 132%. The method was applied to the analysis of rainwater samples collected from two cities in Japan. TFA and several short-chain PFAs were the major compounds found in rainwater.

  14. Assessment of acid-base balance. Stewart's approach.

    Science.gov (United States)

    Fores-Novales, B; Diez-Fores, P; Aguilera-Celorrio, L J

    2016-04-01

    The study of acid-base equilibrium, its regulation and its interpretation have been a source of debate since the beginning of 20th century. Most accepted and commonly used analyses are based on pH, a notion first introduced by Sorensen in 1909, and on the Henderson-Hasselbalch equation (1916). Since then new concepts have been development in order to complete and make easier the understanding of acid-base disorders. In the early 1980's Peter Stewart brought the traditional interpretation of acid-base disturbances into question and proposed a new method. This innovative approach seems more suitable for studying acid-base abnormalities in critically ill patients. The aim of this paper is to update acid-base concepts, methods, limitations and applications. Copyright © 2015 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  15. Cascade impact of hurricane movement, storm tidal surge, sea level rise and precipitation variability on flood assessment in a coastal urban watershed

    Science.gov (United States)

    Joyce, Justin; Chang, Ni-Bin; Harji, Rahim; Ruppert, Thomas; Singhofen, Peter

    2017-11-01

    For comprehensive flood assessment, complex systems, both natural and man-made, must be accounted for due to prevailing cascade effects from the upper atmosphere to the subsurface with hydrological and hydraulic interactions in between. This study aims to demonstrate such cascade effects via an integrated nearshore oceanic and coastal watershed model. Such an integrated modeling system consists of a coupled hydrodynamic circulation and wave driven model [the ADvanced CIRCulation (ADCIRC) and Simulating WAves Nearshore (SWAN) models], which can combine storm surge, astronomic tide levels and wave interaction, as well as an integrated hydrological/hydraulic model, namely the Interconnected Channel and Pond Routing (ICPR) model for coastal urban watershed simulation. In order to explore the worst scenario of coastal flooding impacts on a low-lying coastal watershed, the Cross Bayou Watershed within the Tampa Bay area of Florida was chosen for a multi-scale simulation analysis. To assess hurricane-induced storm tide, precipitation variability, and sea level rise collectively this multi-scale simulation analysis combines ADCIRC/SWAN and ICPR integratively. Findings indicate that such consideration of complex interactions at the coastal ocean, land surface, and sub-surface levels can provide useful flood assessments which are sensitive to slight changes in natural hazard characteristics such as storm intensity, radius of maximum winds, storm track, and landfall location.

  16. 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.

  17. The characteristics changes of pH and EC of atmospheric precipitation and analysis on the source of acid rain in the source area of the Yangtze River from 2010 to 2015

    Science.gov (United States)

    Zong-Jie, Li; Song, Ling-Ling; Jing-zhu, Ma; Li, Yong-ge

    2017-05-01

    Through the analysis of pH value, EC, precipitation and wind speed of 402 precipitation samples in the source region of the Yangtze River from January 1, 2010 to December 31, 2015, especially for the analysis of the 14 acid rain events. The results showed that: the acid rain in the source region of the Yangtze River was mainly affected by the southwest monsoon and the westerly circulation. The occurrence of acid rain mainly controlled by industrial pollution and other pollutants coming from India and other surrounding areas. And the other cause was that because of the Qinghai Tibet highway and the Qinghai Tibet railway, there were a lot of cars coming and going. And there were people in the summer to plateau tourism increased year by year, and more for self-driving travelling. This added additional pollutants (automobile exhaust) for the source of the Yangtze River. During the period of sampling, the variation range of pH value was from 4.0 to 8.57, with the mean was 6.37. And the range of EC was from 5.2 to 124.4 μs/cm, the average was 27.59 μs/cm. The order of conductivity in the four seasons was Spring > Winter > Summer > Autumn. And the order of pH in four seasons was Summer > Spring = Winter > Autumn. The results are also helpful for further understanding the acid rain in the Tibetan Plateau and providing scientific basis for the effective prevention and control of acid rain.

  18. The US Acid Rain Program: design, performance, and assessment

    DEFF Research Database (Denmark)

    Svendsen, Gert Tinggaard

    1998-01-01

    The US Acid Rain Program (ARP) from 1990 allows 1,000 major electric utilities all over the US to trade SO2 permits. Historical emission rights have been grandfathered and the target level is 50% SO2 reduction. Market performance has been successfull with much trade activity and unexpectedly low...

  19. Glycyrrhizic acid: the assessment of a no effect level

    NARCIS (Netherlands)

    van Gelderen, C. E.; Bijlsma, J. A.; van Dokkum, W.; Savelkoul, T. J.

    2000-01-01

    Because from earlier experiments in rats and a pilot study in humans a no-effect level of glycyrrhizic acid could not be established, a second experiment was performed in healthy volunteers. The experiment was performed in females only, because the effects were most marked in females in the pilot

  20. Can serum free fatty acids assessment predict severe preeclampsia?

    African Journals Online (AJOL)

    Nermeen Saad El Beltagy

    2011-10-20

    Oct 20, 2011 ... Abstract Objective: To estimate the relation between serum free fatty acids (FFAs) and severe preeclampsia in Egypt. Methods: Twenty cases with severe preeclampsia (blood pressure P 160/110 after 20th week of ges- tation and proteinuria P 2.5 gm/24 h urine) were matched with 20 normotensive ...

  1. Final report on the safety assessment of Acid Violet 43.

    Science.gov (United States)

    Fiume, M Z

    2001-01-01

    Acid Violet 43 is an anthraquinone color that may be used as a colorant in cosmetic formulations that are hair dyes, colors, and coloring rinses. Batches of Acid Violet 43 that are certified to meet the United States Food and Drug Administration (U.S. FDA) specifications are termed Ext. D & C Violet No. 2. Hair dyes and colors containing Acid Violet 43 are considered coal tar ingredients and, as such, routinely bear a caution statement regarding potential skin irritation and instructions for determining whether the product causes skin irritation in any given individual. Expected concentrations of use are less than or equal to 1%. Impurities include anthracenedione derivatives, p-toluidine, and p-toluidine sulfonic acid, as well as heavy metals. Based on extensive safety test data, the U.S. FDA has established specifications (including limits on impurities) for Ext. D & C Violet No. 2 that allow its use in any cosmetic. It is the certified color (Ext. D & C Violet No. 2) that has been evaluated in the following safety tests. Oral toxicity tests do not demonstrate significant acute toxicity. In a short-term dermal toxicity study using guinea pigs and a subchronic dermal toxicity study using rabbits, no signs of systemic toxicity and no significant local skin reactions were noted. This ingredient was not genotoxic in bacterial assays, nor was it carcinogenic when applied to mouse skin at a 1% concentration. Accordingly, Acid Violet 43 was determined to be safe for use in hair dye formulations, when impurities are limited as follows: colors; or = 80% total color.

  2. Correlation between serum phospholipid fatty acids and dietary intakes assessed a few years earlier.

    Science.gov (United States)

    Thiébaut, Anne C M; Rotival, Maxime; Gauthier, Estelle; Lenoir, Gilbert M; Boutron-Ruault, Marie-Christine; Joulin, Virginie; Clavel-Chapelon, Françoise; Chajès, Véronique

    2009-01-01

    The fatty acid composition of serum phospholipids has been shown to reflect dietary intakes in the previous weeks or months. However, how serum phospholipids relate to fatty acid intakes over a few years has hardly been examined. We designed a cross-sectional study within the E3N cohort, the French component of the European Prospective Investigation into Cancer and Nutrition in which female participants completed a 208-item diet history questionnaire in 1993-1995 and provided blood samples in 1995-1998. The study included 1,114 women who were free of cancer at the time of blood collection. Serum phospholipid fatty acid composition was assessed by capillary gas chromatography. Partial Spearman correlations adjusted for age and body mass index showed weak to moderate, although statistically significant, positive associations between dietary and serum oleic, linoleic, arachidonic, eicosapentaenoic, and docosahexaenoic acids. Moreover, serum oleic acid was directly associated with olive oil, linoleic acid with sunflower oil, pentadecanoic acid with dairy products, long-chain n-3 fatty acids with fatty fish, and trans-monounsaturated fatty acids with manufactured foods. In conclusion, serum phospholipid pentadecanoic acid, oleic, trans-monounsaturated, and polyunsaturated fatty acids are suitable biomarkers for usual dietary intakes, although the association may weaken as the time lag between dietary assessment and blood collection increases.

  3. Development of a new P3 (Probability, Protection, and Precipitation) method for vulnerability, hazard, and risk intensity index assessments in karst watersheds

    Science.gov (United States)

    Sullivan, Timothy P.; Gao, Yongli

    2017-06-01

    Vulnerability, hazard, and risk intensity index (RII) maps are valuable tools for water managers to protect aquifers from contamination. However, in karst aquifers the development of vulnerability and RII maps is subject to explorational bias due to the impracticality of identifying all karst features within watersheds. The P3 method (Probability, Protection, and Precipitation) is proposed to minimize explorational bias through a decision tree model generated from probability maps and nearest neighbor analysis to assign a reduction in aquifer protection based on the probability of encountering karst features. This new method was used in conjunction with previously mapped hazards to assess the vulnerability and RII of nitrate contamination in 2 karst watersheds in semi-arid climate conditions. Validation of the P3 method was conducted with spring hydrographs, tracer tests, nitrate results, and output from a previously developed SWAT model. The maps generated with the P3 method were compared with maps generated from the COP method (Concentration of flow, Overlying layers, Precipitation) using known karst features as well as karst features inferred from analyzing a high resolution Digital Elevation Model (DEM) (COP-DEM method). Validation results show the P3 method most closely estimates the aquifer's vulnerability and RII by minimizing explorational bias. Conversely, the COP method using known karst features underestimates vulnerability and RII by not accounting for all karst features and the COP-DEM method overestimates vulnerability and RII due to false positives of karst features. The P3 method is suitable for all karst aquifers and offers improvements over existing vulnerability mapping methodologies. Namely, the P3 method minimizes explorational bias without requiring knowledge of the location of all karst features within a study area.

  4. Isolation of recombinant proteins from culture broth by co-precipitation with an amino acid carrier to form stable dry powders.

    Science.gov (United States)

    Moore, Barry D; Deere, Joseph; Edrada-Ebel, RuAngelie; Ingram, Andrew; van der Walle, Christopher F

    2010-08-01

    Protein-coated microcrystals can be generated by co-precipitation of protein and a water-soluble crystalline carrier by addition to excess water miscible organic solvent. We have investigated this novel process for its utility in the concentration and partial purification of a recombinant protein exported into the culture broth during expression by Pichia pastoris. Co-precipitation with a L-glutamine carrier selectively isolated the protein content of the culture broth, with a minimal number of steps, and simultaneously removed contaminants including a novel yeast metabolite. This pigment co-elutes during aqueous chromatography but its elucidation as a benzoylated glycosamine suggested a simple route of removal by partition during the co-precipitation process. Scale-up of the process was readily achieved through in-line mixing and subsequent reconstitution of the dried protein-coated microcrystals yielded natively folded, bioactive protein. Additional washing of the crystals with saturated L-glutamine facilitated further purification of the recombinant protein immobilized on the L-glutamine carrier. Thus, we present a novel method for the harvesting of recombinant protein from culture broth as a dry powder, which may be of general applicability to bioprocessing. (c) 2010 Wiley Periodicals, Inc.

  5. Lithium recycling and cathode material regeneration from acid leach liquor of spent lithium-ion battery via facile co-extraction and co-precipitation processes.

    Science.gov (United States)

    Yang, Yue; Xu, Shengming; He, Yinghe

    2017-06-01

    A novel process for extracting transition metals, recovering lithium and regenerating cathode materials based on facile co-extraction and co-precipitation processes has been developed. 100% manganese, 99% cobalt and 85% nickel are co-extracted and separated from lithium by D2EHPA in kerosene. Then, Li is recovered from the raffinate as Li2CO3 with the purity of 99.2% by precipitation method. Finally, organic load phase is stripped with 0.5M H2SO4, and the cathode material LiNi1/3Co1/3Mn1/3O2 is directly regenerated from stripping liquor without separating metal individually by co-precipitation method. The regenerative cathode material LiNi1/3Co1/3Mn1/3O2 is miro spherical morphology without any impurities, which can meet with LiNi1/3Co1/3Mn1/3O2 production standard of China and exhibits good electrochemical performance. Moreover, a waste battery management model is introduced to guarantee the material supply for spent battery recycling. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. A Simple Protein Precipitation-based Simultaneous Quantification of Lovastatin and Its Active Metabolite Lovastatin Acid in Human Plasma by Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry using Polarity Switching.

    Science.gov (United States)

    Wujian, Ju; Kuan-Wei, Peng; Sihyung, Yang; Huijing, Sun; Mario, Sampson; Zhuo, Wang Michael

    2015-05-01

    Lovastatin is an anti-cholesterol lactone drug indicated for the treatment of hyperlipidemia and to reduce the risk of coronary heart disease. It is converted to the β-hydroxy acid form (lovastatin acid) in vivo, which is the major pharmacologically active metabolite. Here, we describe the development and validation of an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)-based method utilizing polarity switching for the simultaneous quantification of lovastatin and lovastatin acid in human plasma. Simple protein precipitation extraction and direct injection of the extracted samples without drying/reconstitution showed good recoveries of both analytes (~70%). The developed method exhibited satisfactory intra-day and inter-day accuracy and precision. The interconversion between lovastatin and lovastatin acid during sample preparation and storage was minimal (acid, respectively, using only 50 μL of plasma during extraction. The validated method was successfully applied to analyze plasma samples obtained from a healthy human subject who enrolled in a clinical drug interaction study involving lovastatin.

  7. Climate change projections for precipitation in Portugal

    Science.gov (United States)

    Andrade, C.; Santos, J. A.

    2013-10-01

    The strong irregularity of precipitation in Portugal, which may e.g. trigger severe/extreme droughts and floods, results in a high vulnerability of the country to precipitation inter-annual variability and to its extremes. Furthermore, dryer future climates are projected for Portugal, though there has also been some growing evidence for a strengthening of precipitation extremes. Due to the central role played byprecipitation on many socio-economic sectors and environmental systems, regional climate change assessments for precipitation in Portugal are necessary. This study is focused on analyzing climate change projections for seasonal (3-month) precipitation totals and their corresponding extremes over mainland Portugal. Taking into account the strong seasonality of the precipitation regimes in Portugal, winter (DJF) and summer (JJA) are considered separately. Precipitation datasets generated by a 16-member ensemble of regional climate model experiments from the ENSEMBLES project are used. Percentile-based indices of precipitation are computed and analyzed for a recent past period (1961-2000) and for a near future period (2041-2070). Results for the R5p, R50p and R95p indices highlight significant projected changes in precipitation, with a clear distinction between northwestern Portugal and the rest of the country in both seasons. Overall, precipitation is projected to decrease in both seasons, particularly over northwestern Portugal in winter, despite some significant regional differences. Although precipitation is projected to decrease in most cases, extremely high seasonal precipitations (above the 95th percentile)areexpected to increase in winter.

  8. Techno-economic assessment of the production of bio-based chemicals from glutamic acid

    NARCIS (Netherlands)

    Lammens, T.M.; Gangarapu, S.; Franssen, M.C.R.; Scott, E.L.; Sanders, J.P.M.

    2012-01-01

    In this review, possible process steps for the production of bio-based industrial chemicals from glutamic acid are described, including a techno-economic assessment of all processes. The products under investigation were those that were shown to be synthesized from glutamic acid on lab-scale, namely

  9. Assessing the importance of spatio-temporal RCM resolution when estimating sub-daily extreme precipitation under current and future climate conditions

    DEFF Research Database (Denmark)

    Sunyer Pinya, Maria Antonia; Luchner, J.; Onof, C.

    2017-01-01

    The increase in extreme precipitation is likely to be one of the most significant impacts of climate change in cities due to increased pluvial flood risk. Hence, reliable information on changes in sub-daily extreme precipitation is needed for robust adaptation strategies. This study explores extr...

  10. Assessing the importance of spatio-temporal RCM resolution when estimating sub-daily extreme precipitation under current and future climate conditions

    DEFF Research Database (Denmark)

    Sunyer Pinya, Maria Antonia; Luchner, J.; Onof, C.

    2017-01-01

    The increase in extreme precipitation is likely to be one of the most significant impacts of climate change in cities due to increased pluvial flood risk. Hence, reliable information on changes in sub-daily extreme precipitation is needed for robust adaptation strategies. This study explores...... extreme precipitation over Denmark generated by the regional climate model (RCM) HIRHAM-ECEARTH at different spatial resolutions (8, 12, 25 and 50km), three RCM from the RiskChange project at 8km resolution and three RCMs from ENSEMBLES at 25km resolution at temporal aggregations from 1 to 48h......) are more consistent across all temporal aggregations in the representation of high-order moments and extreme precipitation. The biases in the spatial pattern of extreme precipitation change across temporal and spatial resolution. The hourly extreme value distributions of the HIRHAM-ECEARTH simulations...

  11. Hexafluorozirconic Acid Based Surface Pretreatments: Characterization and Performance Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Adhikari, Saikat [Ohio State University; Unocic, Kinga A [ORNL; Zhai, Yumei [Ohio State University; Frankel, Gerald [Ohio State University; Zimmerman, John [Henkel Corp; Fristad, W [Henkel Corp

    2010-01-01

    A new phosphate-free pretreatment from Henkel Corp. named TecTalis , was investigated. The treatment bath is composed of dilute hexafluorozirconic acid with small quantities of non-hazardous components containing Si and Cu. The performance of treated steel was compared to samples treated in a phosphate conversion coating bath, in simple hexafluorozirconic acid and in TecTalis without the addition of the Cu containing component. Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM) were used to characterize the coating surface morphology, structure and composition. A Quartz Crystal Microbalance (QCM) was used for studying film growth kinetics on thin films of pure Fe, Al and Zn. Electrochemical Impedance Spectroscopy (EIS) was performed on treated and painted steel for studying long-term corrosion performance of the coatings. The phosphate-free coating provided long-term corrosion performance comparable to that of phosphate conversion coatings. The coatings uniformly cover the surface in the form of 10-20 nm sized nodules and clusters of these features up to 500 nm in size. The coatings are usually about 20-30 nm thick and are mostly composed of Zr and O with enrichment of copper at randomly distributed locations and clusters.

  12. Assessment of the radium-barium co-precipitation and its potential influence on the solubility of Ra in the near-field

    Energy Technology Data Exchange (ETDEWEB)

    Grandia, Fidel; Merino, Joan; Bruno, Jordi (Amphos XXI Consulting S.L., Barcelona (Spain))

    2008-08-15

    Radium 226 is one of the main contributors to radiological dose in some of the scenarios contemplated in the recent SR Can safety assessment. The relative contribution of the 226Ra dose is clearly dependent on the source term value for this radionuclide, which is directly connected to its solubility behaviour. Most of the source term calculations performed for this radionuclide pessimistically assume that its solubility is controlled by the individual solubility of RaSO{sub 4}(s), the most insoluble phase under near field conditions, while the abundant information from early radiochemical research, natural system studies and anthropogenic systems would indicate that Ra(II) is mainly associated to BaSO{sub 4}(s) precipitation. In this work we have investigated the extensive literature concerning the mechanisms and processes controlling the co-precipitation/solid solution formation behaviour of the Ra(II)/Ba(II) sulphate system. We have also established the necessary thermodynamic moles to model the solubility behaviour in the vicinity of the spent fuel system. Calculations using an ATM-104 fuel at 40 MWd/kg U show that barium and radium inventories per canister progressively grow with time after deposition, most of the barium is produced in the initial 500 years. In the unlikely event of a contact of sulphate-containing groundwaters with the fuel, Ba(II) will precipitate as BaSO{sub 4}(s). The production of 226Ra reaches its peak some 300,000 years after deposition. This substantial time gap indicates that most of the BaSO{sub 4}(s) will be present when and if radium is released from the fuel, even if some Ra(II) and Ba(II) will be released contemporaneously. Two potential scenarios have been addressed from the mechanistic point of view. In the event of a simultaneous release of Ra with Ba, the former will be readily incorporated into the precipitating BaSO{sub 4} to build a Ra Ba sulphate solid solution. All the existing evidence indicates, that in this case, the

  13. Serum uric acid levels are associated with homeostasis model assessment in obese nondiabetic patients: HOMA and uric acid.

    Science.gov (United States)

    Elizalde-Barrera, Cesar I; Estrada-García, Teresa; Lozano-Nuevo, Jose J; Garro-Almendaro, Ana K; López-Saucedo, Catalina; Rubio-Guerra, Alberto F

    2017-10-01

    Hyperuricemia leads to insulin resistance, whereas insulin resistance decreases renal excretion of uric acid. The aim of this study was to evaluate whether there is a correlation between serum uric acid levels with homeostatic model assessment (HOMA) 1 in nondiabetic patients. We evaluated 88 nondiabetic patients, in whom uric acid levels were measured, in all of them HOMA of β-cell function (HOMA 1B) and HOMA of insulin resistance (HOMA 1IR) scores were performed. Uric acid and the HOMA 1 values were correlated using the Pearson coefficient. We did not find any correlation between uric acid levels with both HOMA 1B ( r = 0.102, p = 0.343), nor with HOMA 1IR ( r = 0.158, p = 0.117). When patients were analyzed by sex, we found a significant correlation with HOMA 1IR (0.278, p = 0.01), but not with HOMA 1B (0.138, p = 0.257) in women. We found a correlation with HOMA 1B in men ( r = 0.37, p = 0.044), but not with HOMA 1IR: 0.203, p = 0.283. The analysis performed based on body mass index did not show correlation in the patients with normal weight, (HOMA 1B r = 0.08, p = 0.5, HOMA 1IR = 0.034, p = 0.793), nor in the patients who were overweight (HOMA 1B: r = 0.05, p = 0.76, HOMA 1IR r = 0.145, p = 0.43). However, a significant correlation between uricemia with both HOMA 1B (0.559, p uric acid levels seem to be associated with insulin resistance in women, and in obese patients, but not in nonobese men. Uric acid also modifies β-cell function in men and in obese patients.

  14. Advantages of Using Microwave Satellite Soil Moisture over Gridded Precipitation Products and Land Surface Model Output in Assessing Regional Vegetation Water Availability and Growth Dynamics for a Lateral Inflow Receiving Landscape

    NARCIS (Netherlands)

    Chen, T.; McVicar, T.R.; Wang, G.J.; Chen, X.; de Jeu, R.A.M.; Liu, Y.; Shen, H.; Zhang, F.; Dolman, A.J.

    2016-01-01

    To improve the understanding of water-vegetation relationships, direct comparative studies assessing the utility of satellite remotely sensed soil moisture, gridded precipitation products, and land surface model output are needed. A case study was investigated for a water-limited, lateral inflow

  15. Quality assessment of some brands of vitamin C (ascorbic acid ...

    African Journals Online (AJOL)

    The quality of some brands of vitamin C tablets marketed in the city of Uyo, Nigeria was assessed. All the ten samples passed the uniformity of weight and disintegration time tests as specified in the British Pharmacopoeia and. United States Pharmacopoeia for effervescent, uncoated, dispersible tablets. However, the ...

  16. Assessment of acidity levels in Eucalyptus Camaldulensis barks ...

    African Journals Online (AJOL)

    Bark samples of Eucalyptus camaldulensis obtained from Bauchi and Gombe States were analysed spectrophotometrically for their sulphate-sulphur content. The aim was to assess the extent of sulphur pollution in the environment. The results showed that S concentration ranged from 0.79 to 1.70mg/g for samples from ...

  17. Establishment and assessment of an integrated citric acid-methane production process.

    Science.gov (United States)

    Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Bao, Jia-Wei; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2015-01-01

    To solve the problem of extraction wastewater in citric acid industrial production, an improved integrated citric acid-methane production process was established in this study. Extraction wastewater was treated by anaerobic digestion and then the anaerobic digestion effluent (ADE) was stripped by air to remove ammonia. Followed by solid-liquid separation to remove metal ion precipitation, the supernatant was recycled for the next batch of citric acid fermentation, thus eliminating wastewater discharge and reducing water consumption. 130U/g glucoamylase was added to medium after inoculation and the recycling process performed for 10 batches. Fermentation time decreased by 20% in recycling and the average citric acid production (2nd-10th) was 145.9±3.4g/L, only 2.5% lower than that with tap water (149.6g/L). The average methane production was 292.3±25.1mL/g CODremoved and stable in operation. Excessive Na(+) concentration in ADE was confirmed to be the major challenge for the proposed process. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. External radiation assessment in a wet phosphoric acid production plant

    Energy Technology Data Exchange (ETDEWEB)

    Bolivar, J.P.; Perez-Moreno, J.P. [Dept. Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, 21012 Huelva (Spain); Mas, J.L. [Dept. Fisica Aplicada I, Escuela Universitaria Politecnica, Universidad de Sevilla, 41012 Sevilla (Spain)], E-mail: ppmasb@us.es; Martin, J.E.; San Miguel, E.G. [Dept. Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, 21012 Huelva (Spain); Garcia-Tenorio, R. [Dept. Fisica Aplicada II, Escuela Tecnica Superior de Arquitectura, Universidad de Sevilla, 41012 Sevilla (Spain)

    2009-10-15

    The factories dedicated to the production of phosphoric acid by the so-called wet acid method are usually considered typical NORM industries, because the phosphate rock used as raw material usually contains high concentrations of {sup 238}U-series radionuclides. The magnitude and behaviour of the radionuclides involved in the production process revealed the need to determine its dosimetric impact on workers. This work aims to partially compensate this lack of knowledge through the determination of external effective dose rates at different zones in the process at a typical plant located in the southwest of Spain. To this end, two dosimetric sampling campaigns have been carried out at this phosphoric acid production plant. The first sampling was carried out when phosphate rocks originating in Morocco were processed, and the second one when phosphate rock processed came from the Kola Peninsula (Russia Federation). This differentiation was necessary because the activity concentrations are almost one order of magnitude higher in Moroccan phosphate rock than in Kola phosphate rock. The results obtained have reflected external dose rate enhancements as high as 1.4 {mu}Sv h{sup -1} (i.e., up to thirty times the external exposition due to radionuclides in unperturbed soils) at several points in the facility, particularly where the digested rock (pulp) is filtered. However, the most problematic points are characterised by a small occupation factor. That means that the increment in the annual effective external gamma dose received by the most-exposed worker is clearly below 1 mSv (European Commission limit for the general population) under normal production. Nevertheless, special care in the design and schedule of cleaning and maintaining work in the areas with high doses should be taken in order to avoid any possibility of exceeding the previously mentioned general population limit. In addition, the results of the dosimetric campaign showed no clear correlation between {sup

  19. Assessment of the influence of magnesium content on the shape and amount of graphite precipitation in spheroidal cast iron manufactured by Metal-Odlew s.c.

    Directory of Open Access Journals (Sweden)

    W. Orłowicz

    2009-01-01

    Full Text Available The study presents the influence of time on cast iron spheroidisation, modification of the magnesium content in the alloy, and the influence of the magnesium content on the shape and number of graphite precipitations. For one particular set of production conditions, it was observed that 17 minutes after completing the modification and spheroidisation procedure, the magnesium content had decreased from 0.070% to 0.040%. This resulted in a decrease in the graphite precipitation shape index Ss from 0.081 to 0.067, as well as a decrease in the average number of graphite precipitations NA from 568 mm-2 to 305 mm-2.

  20. 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...

  1. Recent advances in the risk assessment of melamine and cyanuric acid in animal feed

    Energy Technology Data Exchange (ETDEWEB)

    Dorne, Jean Lou, E-mail: jean-lou.dorne@efsa.europa.eu [Unit on Contaminants, European Food Safety Authority, Largo N. Palli 5/A, 43121 Parma (Italy); Doerge, Daniel R. [NCTR, Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079 (United States); Vandenbroeck, Marc [Unit on Contaminants, European Food Safety Authority, Largo N. Palli 5/A, 43121 Parma (Italy); Fink-Gremmels, Johanna [University of Utrecht (Netherlands); Mennes, Wim [RIVM, Bilthoven (Netherlands); Knutsen, Helle K. [Norwegian Institute of Public Health, Oslo (Norway); Vernazza, Francesco [Dietary and Chemical Monitoring, European Food Safety Authority, Largo N. Palli 5/A, 43121 Parma (Italy); Castle, Laurence [FERA, York (United Kingdom); Edler, Lutz [German Cancer Research Center, Heidelberg (Germany); Benford, Diane [Food Standard Agency, London (United Kingdom)

    2013-08-01

    Melamine can be present at low levels in food and feed mostly from its legal use as a food contact material in laminates and plastics, as a trace contaminant in nitrogen supplements used in animal feeds, and as a metabolite of the pesticide cyromazine. The mechanism of toxicity of melamine involves dose-dependent formation of crystals with either endogenous uric acid or a structural analogue of melamine, cyanuric acid, in renal tubules resulting in potential acute kidney failure. Co-exposure to melamine and cyanuric acid in livestock, fish, pets and laboratory animals shows higher toxicity compared with melamine or cyanuric acid alone. Evidence for crystal formation between melamine and other structural analogs i.e. ammelide and ammeline is limited. Illegal pet food adulterations with melamine and cyanuric acid and adulteration of milk with melamine resulted in melamine–cyanuric acid crystals, kidney damage and deaths of cats and dogs and melamine–uric acid stones, hospitalisation and deaths of children in China respectively. Following these incidents, the tolerable daily intake for melamine was re-evaluated by the U.S. Food and Drug Administration, the World Health Organisation, and the Scientific Panel on Contaminants in the Food Chain of the European Food Safety Authority (EFSA). This review provides an overview of toxicology, the adulteration incidents and risk assessments for melamine and its structural analogues. Particular focus is given to the recent EFSA risk assessment addressing impacts on animal and human health of background levels of melamine and structural analogues in animal feed. Recent research and future directions are discussed. - Highlights: ► Melamine in food and feed. ► Forms crystals in kidney with uric acid or cyanuric acid. ► Toxicity higher with cyanuric acid. ► Recent EFSA risk assessment. ► Animal and human health.

  2. Assessment of Phytostabilization Success in Metalliferous Acid Mine Tailings

    Science.gov (United States)

    Wang, Y.; Root, R. A.; Hammond, C.; Amistadi, M. K.; Maier, R. M.; Chorover, J.

    2014-12-01

    Legacy mine tailings are a significant source of metal(loid)s due to wind and water erosion, especially in the arid southwest, and exposure to fugative dusts presents a health risk to surrounding populations. Compost assisted phytostabilization has been implemented to reduce off site emissions at the Iron King Mine U.S. Superfund Site in central Arizona, concurrent with a greenhouse mesocosm study for detailed study of subsurface mechanisms. Quantification of plant available toxic metal(loid)s in the amended tailings was accessed with a targeted single extraction of diethylenetriaminepentaactic acid (DTPA). Greenhouse mesocosms (1m dia, 0.4 m deep), run in triplicate, mimicked field treatments with: i) tailings only control (TO), ii) tailings plus 15 wt% compost (TC), iii) TC + quailbush seeds (TCA), and iv) TC + buffalo grass seeds (TCB). Core samples collected at 3-month intervals for 1 year were dissected by depth (10 cm each) for analysis. DTPA results indicated that compost treated samples decreased plant availability of Al, As, Cd, Cu, Fe, and Pb but increased Mn and Zn compared with TO. TCB decreased plant available metal(loid)s at all depths, whereas TCA plant available Al, As, Cd, Cu, Fe, Mn and Zn increased in the deeper 20-30cm and 30-40 cm relative to TCB. Samples from the greenhouse were compared to tailings from both the field site and tailings impacted soils used to grow vegetables. Mineral transformations and metal complexation, in the pre- and post-extracted tailings were analyzed by synchrotron transmission XRD and FTIR spectroscopy. The temporal change in plant available metal(loid)s in response to phytostabilization indicates mineralogical alteration that improves soil quality by reducing plant available metal(loid)s. These results will aid in the understanding and efficacy of phytostabilization as a means of remediating and reducing toxicity on mine tailings as well as providing information on health risk management in the region.

  3. Recovery of Plutonium by Carrier Precipitation

    Science.gov (United States)

    Goeckermann, R. H.

    1961-04-01

    The recovery of plutonium from an aqueous nitric acid Zr-containing solution of 0.2 to 1N acidity is accomplished by adding fluoride anions (1.5 to 5 mg/l), and precipitating the Pu with an excess of H/sub 2/0/sub 2/ at 53 to 65 deg C. (AEC)

  4. Targeted toxicological screening for acidic, neutral and basic substances in postmortem and antemortem whole blood using simple protein precipitation and UPLC-HR-TOF-MS

    DEFF Research Database (Denmark)

    Telving, Rasmus; Hasselstrøm, Jørgen Bo; Andreasen, Mette Findal

    2016-01-01

    -HR-TOF-MS was achieved in one injection. This method covered basic substances, substances traditionally analyzed in negative ESI (e.g., salicylic acid), small highly polar substances such as beta- and gamma-hydroxybutyric acid (BHB and GHB, respectively) and highly non-polar substances such as amiodarone. The new method......A broad targeted screening method based on broadband collision-induced dissociation (bbCID) ultra-performance liquid chromatography high-resolution time-of-flight mass spectrometry (UPLC-HR-TOF-MS) was developed and evaluated for toxicological screening of whole blood samples. The acidic, neutral...... was performed on spiked whole blood samples and authentic postmortem and antemortem whole blood samples. For most of the basic drugs, the established cut-off limits were very low, ranging from 0.25ng/g to 50ng/g. The established cut-off limits for most neutral and acidic drugs, were in the range from 50ng...

  5. Critical load of acid precipitations. Mapping of Italian regions; Mappa dei carichi critici di acidita' totale riferita al territorio italiano

    Energy Technology Data Exchange (ETDEWEB)

    Bonanni, P.; Brini, S.; Delmonaco, G.; Liburdi, R.; Trocciola, A.; Vetrella, G. [ENEA Centro Ricerche Casaccia, S. Maria di Galeria, RM (Italy). Dipt. Ambiente

    1999-07-01

    In this report the mapping of critical loads of acidity for the Italian terrestrial ecosystems is presented. The level O method (Stockholm Environment Institute) has been used to determine sensitivity to acid deposition; this semi-quantitative method has been modified to address some Italian characteristics. The results show that the sensitivity of the Italian soils to acidification is not particularly elevated: there are really only few small areas with poor tolerance to acid depositions. These areas are in the north-east of Italy, in Alpine and Prealpine region. [Italian] Nel rapporto vengono riportati i risultati della mappatura, riferita agli ecosistemi terrestri del territorio italiano, dei carichi critici per l'acidita' totale. Il calcolo dei carichi critici e' stato eseguito sulla base della metodologia messa a punto dallo Stokholm Environment Institute; a questo metodo semi-quantitativo sono state apportate alcune modifiche per meglio adattarlo alle caratteristiche del territorio italiano. Dall'analisi dei risultati ottenuti, si evince come la sensibilita' dei suoli italiani all'acidificazione non sia particolarmente elevata: sono state riscontrate infatti solo alcune aree, peraltro con superficie limitata, con una scarsa tolleranza alle deposizioni acide. Tali aree sono localizzate nell'Italia nord-orientale, in zona alpina e prealpina.

  6. The use of dielectric spectroscopy for the characterisation of the precipitation of hydrophobically modified poly(acrylic-acid) with divalent barium ions

    DEFF Research Database (Denmark)

    Christensen, Peter Vittrup; Keiding, Kristian

    2009-01-01

    The use of dielectric spectroscopy as a monitor for coagulation processes was investigated. Hydrophobically modified poly(acrylic-acid) polymers were used as model macromolecules and coagulated with barium ions. The coagulation process was quantified using a photometric dispersion analyser, thereby...

  7. Effects of aqueous complexation on reductive precipitation of uranium by Shewanella putrefaciens

    Directory of Open Access Journals (Sweden)

    Northup Abraham

    2004-10-01

    Full Text Available We have examined the effects of aqueous complexation on rates of dissimilatory reductive precipitation of uranium by Shewanella putrefaciens. Uranium(VI was supplied as sole terminal electron acceptor to Shewanella putrefaciens (strain 200R in defined laboratory media under strictly anaerobic conditions. Media were amended with different multidentate organic acids, and experiments were performed at different U(VI and ligand concentrations. Organic acids used as complexing agents were oxalic, malonic, succinic, glutaric, adipic, pimelic, maleic, citric, and nitrilotriacetic acids, tiron, EDTA, and Aldrich humic acid. Reductive precipitation of U(VI, resulting in removal of insoluble amorphous UO2 from solution, was measured as a function of time by determination of total dissolved U. Reductive precipitation was measured, rather than net U(VI reduction to U(IV, to assess overall U removal rates from solution, which may be used to gauge the influence of chelation on microbial U mineralization. Initial linear rates of U reductive precipitation were found to correlate with stability constants of 1:1 aqueous U(VI:ligand and U(IV:ligand complexes. In the presence of strongly complexing ligands (e.g., NTA, Tiron, EDTA, UO2 precipitation did not occur. Our results are consistent with ligand-retarded precipitation of UO2, which is analogous to ligand-assisted solid phase dissolution but in reverse: ligand exchange with the U4+ aquo cation acts as a rate-limiting reaction moderating coordination of water molecules with U4+, which is a necessary step in UO2 precipitation. Ligand exchange kinetics governing dissociation rates of ligands from U(VI-organic complexes may also influence overall UO2 production rates, although the magnitude of this effect is unclear relative to the effects of U(IV-organic complexation. Our results indicate that natural microbial-aqueous systems containing abundant organic matter can inhibit the formation of biogenic amorphous UO2.

  8. IMPROVED PROCESS OF PLUTONIUM CARRIER PRECIPITATION

    Science.gov (United States)

    Faris, B.F.

    1959-06-30

    This patent relates to an improvement in the bismuth phosphate process for separating and recovering plutonium from neutron irradiated uranium, resulting in improved decontamination even without the use of scavenging precipitates in the by-product precipitation step and subsequently more complete recovery of the plutonium in the product precipitation step. This improvement is achieved by addition of fluomolybdic acid, or a water soluble fluomolybdate, such as the ammonium, sodium, or potassium salt thereof, to the aqueous nitric acid solution containing tetravalent plutonium ions and contaminating fission products, so as to establish a fluomolybdate ion concentration of about 0.05 M. The solution is then treated to form the bismuth phosphate plutonium carrying precipitate.

  9. Assessing physio-macromolecular effects of lactic acid on Zygosaccharomyces bailii cells during microaerobic fermentation.

    Science.gov (United States)

    Kuanyshev, Nurzhan; Ami, Diletta; Signori, Lorenzo; Porro, Danilo; Morrissey, John P; Branduardi, Paola

    2016-08-01

    The ability of Zygosaccharomyces bailii to grow at low pH and in the presence of considerable amounts of weak organic acids, at lethal condition for Saccharomyces cerevisiae, increased the interest in the biotechnological potential of the yeast. To understand the mechanism of tolerance and growth effect of weak acids on Z. bailii, we evaluated the physiological and macromolecular changes of the yeast exposed to sub lethal concentrations of lactic acid. Lactic acid represents one of the important commodity chemical which can be produced by microbial fermentation. We assessed physiological effect of lactic acid by bioreactor fermentation using synthetic media at low pH in the presence of lactic acid. Samples collected from bioreactors were stained with propidium iodide (PI) which revealed that, despite lactic acid negatively influence the growth rate, the number of PI positive cells is similar to that of the control. Moreover, we have performed Fourier Transform Infra-Red (FTIR) microspectroscopy analysis on intact cells of the same samples. This technique has been never applied before to study Z. bailii under this condition. The analyses revealed lactic acid induced macromolecular changes in the overall cellular protein secondary structures, and alterations of cell wall and membrane physico-chemical properties. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Advantages of Using Microwave Satellite Soil Moisture over Gridded Precipitation Products and Land Surface Model Output in Assessing Regional Vegetation Water Availability and Growth Dynamics for a Lateral Inflow Receiving Landscape

    Directory of Open Access Journals (Sweden)

    Tiexi Chen

    2016-05-01

    Full Text Available To improve the understanding of water–vegetation relationships, direct comparative studies assessing the utility of satellite remotely sensed soil moisture, gridded precipitation products, and land surface model output are needed. A case study was investigated for a water-limited, lateral inflow receiving area in northeastern Australia during December 2008 to May 2009. In January 2009, monthly precipitation showed strong positive anomalies, which led to strong positive soil moisture anomalies. The precipitation anomalies disappeared within a month. In contrast, the soil moisture anomalies persisted for months. Positive anomalies of Normalized Difference Vegetation Index (NDVI appeared in February, in response to water supply, and then persisted for several months. In addition to these temporal characteristics, the spatial patterns of NDVI anomalies were more similar to soil moisture patterns than to those of precipitation and land surface model output. The long memory of soil moisture mainly relates to the presence of clay-rich soils. Modeled soil moisture from four of five global land surface models failed to capture the memory length of soil moisture and all five models failed to present the influence of lateral inflow. This case study indicates that satellite-based soil moisture is a better predictor of vegetation water availability than precipitation in environments having a memory of several months and thus is able to persistently affect vegetation dynamics. These results illustrate the usefulness of satellite remotely sensed soil moisture in ecohydrology studies. This case study has the potential to be used as a benchmark for global land surface model evaluations. The advantages of using satellite remotely sensed soil moisture over gridded precipitation products are mainly expected in lateral-inflow and/or clay-rich regions worldwide.

  11. Formation of stratospheric nitric acid by a hydrated ion cluster reaction: Implications for the effect of energetic particle precipitation on the middle atmosphere

    Science.gov (United States)

    Kvissel, O.-K.; Orsolini, Y. J.; Stordal, F.; Isaksen, I. S. A.; Santee, M. L.

    2012-08-01

    In order to improve our understanding of the effects of energetic particle precipitation on the middle atmosphere and in particular upon the nitrogen family and ozone, we have modeled the chemical and dynamical middle atmosphere response to the introduction of a chemical pathway that produces HNO3 by conversion of N2O5 upon hydrated water clusters H+·(H2O)n. We have used an ensemble of simulations with the National Center for Atmospheric Research (NCAR) Whole-Atmosphere Community Climate Model (WACCM) chemistry-climate model. The chemical pathway alters the internal partitioning of the NOy family during winter months in both hemispheres, and ultimately triggers statistically significant changes in the climatological distributions of constituents including: i) a cold season production and loss of HNO3 and N2O5, respectively, and ii) a cold season decrease and increase in NOx/NOy-ratio and O3, respectively, in the polar regions of both hemispheres. We see an improved seasonal evolution of modeled HNO3 compared to satellite observations from Microwave Limb Sounder (MLS), albeit not enough HNO3 is produced at high altitudes. Through O3changes, both temperature and dynamics are affected, allowing for complex chemical-dynamical feedbacks beyond the cold season when the pathway is active. Hence, we also find a NOxpolar increase in spring-to-summer in the southern hemisphere, and in spring in the northern hemisphere. The springtime NOxincrease arises from anomalously strong poleward transport associated with a weaker polar vortex. We argue that the weakening of zonal-mean polar winds down to the lower stratosphere, which is statistically significant at the 0.90 level in spring months in the southern hemisphere, is caused by strengthened planetary waves induced by the middle and sub-polar latitude zonal asymmetries in O3and short-wave heating.

  12. Spatiotemporal assessment of historical skill and projected future changes in CORDEX South Asia ensemble simulation of precipitation and temperature for the Upper Indus Basin

    Science.gov (United States)

    Forsythe, Nathan; Fowler, Hayley; Pritchard, David

    2017-04-01

    High mountain Asia (HMA), including the Hindu Kush-Karakoram, Himalayas and Tibetan Plateau, constitutes one the key "water towers of the world", giving rise to river basins whose resources support hundreds of millions of people. This area is currently experiencing substantial demographic growth and socio-economic development. This evolution will likely continue for the next few decades and compound pressure on resource managements systems from inevitable climate change. In order to develop climate services to support water resources planning and facilitate adaptive capacity building, it is essential to critically characterise the skill and biases of the evaluation (reanalysis-driven) and control (historical period) components of presently available regional climate model (RCM) experiments. For mountain regions in particular, the ability of RCMs to reasonably reproduce the influence of complex topography, through lapse rates and orographic forcing, on sub-regional climate - notably temperature and precipitation - must be assessed in detail. This is vital because the spatiotemporal distribution of precipitation and temperature in mountains determine the seasonality of streamflow from the headwater reaches and of major river basins. Once the biases of individual GCM/RCM experiments have been identified methodologies can be developed for modulating (correcting) the projected patterns of change identified by comparing simulated climate sub-regional climate under specific emissions scenarios (e.g. RCP8.5) to historical representations by the same model (time-slice approach). Such methods could for example include calculating temperature change factors as a function elevation difference from present 0°C (freezing) isotherm rather than simply using the overlying RCM grid cell if for instance the RCM showed exacerbated temperature increase at snow line (i.e. albedo feedback in elevation dependent warming) but also showed a pronounced bias in the historical (vertical

  13. Assessment of the microbial community in a constructed wetland that receives acid coal mine drainage

    Energy Technology Data Exchange (ETDEWEB)

    Nicomrat, D.; Dick, W.A.; Tuovinen, O.H. [Ohio State University, Columbus, OH (United States)

    2006-01-15

    Constructed wetlands are used to treat acid drainage from surface or underground coal mines. However, little is known about the microbial communities in the receiving wetland cells. The purpose of this work was to characterize the microbial population present in a wetland that was receiving acid coal mine drainage (AMD). Samples were collected from the oxic sediment zone of a constructed wetland cell in southeastern Ohio that was treating acid drainage from an underground coal mine seep. Samples comprised Fe(Ill) precipitates and were pretreated with ammonium oxalate to remove interfering iron, and the DNA was extracted and purified by agarose gel electrophoresis prior to amplification of portions of the 16S rRNA gene. Amplified products were separated by denaturing gradient gel electrophoresis and DNA from seven distinct bands was excised from the gel and sequenced. The sequences were matched to sequences in the GenBank bacterial 16S rDNA database. The DNA in two of the bands yielded matches with Acidithiobacillus ferrooxidans and the DNA in each of the remaining five bands was consistent with one of the following microorganisms: Acidithiobacillus thiooxidans, strain TRA3-20 (a eubacterium), strain BEN-4 (an arsenite-oxidizing bacterium), an Alcaligenes sp., and a Bordetella sp. Low bacterial diversity in these samples reflects the highly inorganic nature of the oxic sediment layer where high abundance of iron- and sulfur-oxidizing bacteria would be expected. The results we obtained by molecular methods supported our findings, obtained using culture methods, that the dominant microbial species in an acid receiving, oxic wetland are A. thiooxidans and A. ferrooxidans.

  14. Assessing shrub encroachment in a grassland-shrubland desert ecotone using the relationship between remote sensed phenology of vegetation and precipitation

    Science.gov (United States)

    Moreno de las Heras, Mariano; Diaz-Sierra, Ruben; Wainwright, John

    2014-05-01

    Climate change and the massive alteration of natural habitats are major drivers of land degradation. Their effects may be especially significant in drylands, where ecosystems are particularly sensitive to degradation, usually involving largely irreversible landscape changes. A paradigmatic case of catastrophic vegetation shift is the shrub-encroachment process that has been taking place over the last 150 years in the Chihuahuan Desert, where large areas of grasslands dominated by perennial grass species (black and blue grama) have shifted to shrublands dominated by woody species (creosotebush and mesquite) accompanied by accelerated water and wind erosion. An array of mechanisms are involved in this process, including external triggering factors such as precipitation and land-use variations, and endogenous amplifying mechanisms brought about by soil erosion-vegetation feedbacks. We track landscape changes at a 20 km2 grasland-shrubland ecotone in the northern edge of the Chihuahuan Desert (McKenzie Flats, Sevilleta LTER site, New Mexico) by studying the relationship between long-term (2000-13) records of medium-resolution remote sensing of landscape phenology (MODIS NDVI) and precipitation. We hypothesize that grass and shrub life-forms exhibit important differences in phenology and water use. Our analysis indicates that herbaceous vegetation (grasses and forbs) shows quick growth pulses associated with short-term (previous 2 months) precipitation, while shrubs show a slow response to medium-term (previous 5 months) precipitation. We use these relationships to (a) determine the broad-scale spatial distribution of herbaceous vegetation and shrubs in our study site, and to (b) decompose and transform the NDVI signal into partial NPP components for herbaceous vegetation and shrubs. We further analyze the influence of inter-annual variations in seasonal precipitation on remotely sensed NPP data. Plant growth for herbaceous vegetation is particularly synchronized with

  15. The antagonizing effect of aspartic acid on morphine withdrawal and levallorphan-precipitated abstinence syndrome signs and on associated changes in brain levels of free amino acids in the rat.

    Science.gov (United States)

    Koyuncuoğlu, H; Güngör, M; Eroğlu, L; Sağduyu, H

    1979-03-29

    We have previously demonstrated the antagonizing effect of aspartic acid on some effects of morphine and on the development of physical dependence on, and tolerance to, morphine. In the present study, we have withdrawal from morphine or administration of a morphine antagonist. For this purpose sixty five white rats were given morphine and aspartic acid separately and in combination in a 5% saccharose solution instead of drinking water for 30 days. Some of the dependent rats were then withdrawn and others were injected with levallorphan. Flying, jumping, wet-dog shaking, body weight loss and motor activity were estimated and free amino acid levels in the brain were determined. Aspartic acid was found to prevent or antagonize the behavioural signs and the changes in the free amino acid levels in the brain. The results are discussed in the light of the previous data.

  16. Assessment of folic acid and DNA damage in cleft lip and cleft palate

    Directory of Open Access Journals (Sweden)

    Sivakumar Brooklyin

    2014-03-01

    Full Text Available Studies have identified the risk factors like folic acid deficiency during gestational period, family history for orofacial clefts, drugs like antiepileptic, vitamin A. But, the data regarding the folic acid status in children with cleft lip/palate is hardly evaluated in depth. Here, an assessment of folic acid and DNA damage were carried out in children with orofacial anomalies. Folic acid level and DNA damage were evaluated by folic acid assay (direct chemiluminescent technology and single cell gel electrophoresis or comet assay method respectively. The mean value of plasma folic acid by direct chemiluminescent technology was 6.5±3.6 nmol/L and the normal value in children ranges from 11.3 to 47.6 nmol/L. The amount of damaged DNA, measured as the tail length of the comet in cases, was 19.4±8.9 ?m and the mean percentage of DNA in tail was 16.5±3.7. Folic acid deficiency could be the reason for DNA damage.

  17. Assessing diet compositions of Lake Ontario predators using fatty acid profiles of prey fishes

    Science.gov (United States)

    Happell, Austin; Pattridge, Robert; Rinchard, Jacques; Walsh, Maureen

    2017-01-01

    Fatty acid profiles are used in food web studies to assess trophic interactions between predator and prey. The present study provides the first comprehensive fatty acid dataset for important prey and predator species in Lake Ontario. Three major prey fish (alewife, rainbow smelt, and round goby) were collected at three sites along the southern shore of Lake Ontario during the spring and fall of 2013, and predator species were collected in similar locations during the summer of 2013. Fatty acid compositions were compared among all prey species, all predator species, and information from both predator and prey was used to infer foraging differences among predators. Seasonal differences in fatty acids were found within each prey species studied. Differences among prey species were greater than any spatio-temporal differences detected within species. Fatty acids of predators revealed species-specific differences that matched known foraging habits. Chinook and Coho salmon, which are known to select alewife as their dominant prey item, had relatively little variation in fatty acid profiles. Conversely, brown trout, lake trout, yellow perch and esocids had highly variable fatty acid profiles and likely highly variable diet compositions. In general, our data suggested three dominant foraging patterns: 1) diet composed of nearly exclusively alewife for Chinook and Coho Salmon; 2) a mixed diet of alewife and round goby for brown and lake trout, and both rock and smallmouth bass; 3) a diet that is likely comprised of forage fishes other than those included in our study for northern pike and chain pickerel.

  18. Assessment of total sialic acid levels in patients with hyperemesis gravidarum: a preliminary study.

    Science.gov (United States)

    Demir, Sevgi Sari; Özcan, Hüseyin Çağlayan; Balat, Özcan; Öztürk, Ebru; Uğur, Mete Gurol; Gündüz, Reyhan; Taysi, Seyithan

    2018-02-01

    To determine the levels of serum total sialic acid (TSA) in patients with hyperemesis gravidarum (HG) and their gestational age-matched controls. Thirty pregnant women with HG, and 30 healthy pregnant women at up to 14 weeks of gestation were enrolled in this preliminary study. Total sialic acid levels in maternal serum were measured using the quantitative sandwich ELISA method. We observed statistically significant difference in TSA levels between HG and the control groups (p = .003). The identification of the role of SA in the prediction, diagnosis and follow-up of HG warrants more comprehensive studies in the future. Impact Statement What is already known on this subject? The derivatives of neuraminic acid are collectively referred to as sialic acid (SA). Changes in SA levels are known to trigger various conditions and disorders, including inflammatory, cardiovascular, neurological and endocrine diseases. Although a sensitive test capable of identifying hyperemesis gravidarum (HG) would be useful for diagnosis purposes, such a test is currently not available. Studies focussing on identifying new potential indicators and biomarkers for HG - as well as identifying their relevance in establishing diagnosis and assessing disease severity - would not only assist in elucidating the underlying causes of this condition but would also contribute to the development of new diagnostic tests for HG. What the results of this study add? Total sialic acid levels are significantly higher in sera of the patients with HG. The present study is the first in the literature to assess total sialic acid levels in patients with HG and healthy pregnant women before 14 weeks of gestation. What the implications are of these findings for clinical practice and/or further research? Total sialic acid levels could give an idea to clinicians in the etiopathogenesis of HG. The identification of the role of sialic acid in the prediction, diagnosis and follow-up of HG warrants more

  19. Using Diagnostic Assessment to Help Teachers Understand the Chemistry of the Lead-Acid Battery

    Science.gov (United States)

    Cheung, Derek

    2011-01-01

    Nineteen pre-service and in-service teachers taking a chemistry teaching methods course at a university in Hong Kong were asked to take a diagnostic assessment. It consisted of seven multiple-choice questions about the chemistry of the lead-acid battery. Analysis of the teachers' responses to the questions indicated that they had difficulty in…

  20. Assessment of flavonoid and fatty acid intake by chemical analysis of biomarkers and the duplicate diets

    NARCIS (Netherlands)

    Vries, de J.H.M.

    1998-01-01

    Dietary intake is important to investigate the relationship between diet and the occurrence of disease. However, it is difficult to assess the intake of nutrients such as flavonoids, minor fatty acids and plant sterols because the data on these nutrients in food composition tables are insufficient

  1. [VOLATILE FATTY ACIDS IN SALIVA--BIOLOGICAL MARKERS FOR ASSESSMENT OF DRINKING WATER POLLUTANTS ON CHILDREN].

    Science.gov (United States)

    Akaizina, A E; Akaizin, E S; Starodumov, V L

    2015-01-01

    The use of modern methods of analysis is aimed to the search of ultimately novel biological markers. Volatile fatty acids in saliva were not used previously for the assessment of the effects of contaminating substances in the drinking water on the body of children. The aim of the study is to investigate the informative value of volatile fatty acids in saliva as biological markers of the impact for the assessment of the exposure to contaminating substances in the drinking water on the body of children. Hygienic assessment of drinking water quality was made according to data of the own research of drinking water from centralized supply system of the city of Ivanovo. For the comparison of indices there was investigated the drinking water from wells at the village Podvyaznovsky of the Ivanovo region. In the Ivanovo water from the distributing network of centralized drinking water supply system of the city of Ivanovo, there were identified indices of the permanganate oxidation and the total concentration of residual chlorine exceeding norms, and also chloroform and carbon tetrachloride were in concentrations not exceeding the norms. Studied by us the samples of drinking water from Podvyaznovsky village wells, the water met the standards for all investigated parameters. The was studied the informative value of volatile fatty acids in the saliva of children aged 9-14 years from the city of Ivanovo and the Podvyaznovsky village, Ivanovo region. There was established the fall in acetic, butyric, isovaleric acids and the total amount of volatile fatty acids in the saliva in children of the city of Ivanovo, consuming water treated with chlorine of Ivanovo centralized drinking water supply system. Indices of volatile fatty acids in saliva are informative for the assessment of the impact of organic pollutants, residual chlorine and organic chlorine compounds of drinking water on the body of children.

  2. Interannual and (multi-)decadal variability in the sedimentary BIT index of Lake Challa, East Africa, over the past 2200 years: assessment of the precipitation proxy

    NARCIS (Netherlands)

    Buckles, L.K.; Verschuren, D.; Weijers, J.W.H.; Cocquyt, C.; Blaauw, M.; Sinninghe Damsté, J.S.

    2016-01-01

    The branched vs. isoprenoid tetraether (BIT) index is based on the relative abundance of branched tetraether lipids (brGDGTs) and the isoprenoidal GDGT crenarchaeol. In Lake Challa sediments the BIT index has been applied as a proxy for local monsoon precipitation on the assumption that the primary

  3. Validation of a homogeneous 41-year (1961-2001) winter precipitation hindcasted dataset over the Iberian Peninsula: assessment of the regional improvement of global reanalysis

    Energy Technology Data Exchange (ETDEWEB)

    Sotillo, M.G. [Area de Medio Fisico, Puertos del Estado, Madrid (Spain); Martin, M.L. [Universidad de Valladolid, Dpto. Matematica Aplicada, Escuela Universitaria de Informatica, Campus de Segovia, Segovia (Spain); Valero, F. [Universidad Complutense de Madrid, Dpto. Astrofisica y CC. de la Atmosfera, Facultad de CC Fisicas, Madrid (Spain); Luna, M.Y. [Instituto Nacional de Meteorologia, Madrid (Spain)

    2006-11-15

    A 44-year (1958-2001) homogeneous, Mediterranean, high-resolution atmospheric database was generated through dynamical downscaling within the HIPOCAS (Hindcast of Dynamic Processes of the Ocean and Coastal Areas of Europe) Project framework. This work attempts to provide a validation of the monthly winter HIPOCAS precipitation over the Iberian Peninsula and the Balearic Islands and to evaluate the potential improvement of these new hindcasted data versus global reanalysis datasets. The validation was performed through the comparative analysis with a precipitation database derived from 4,617 in situ stations located over Iberia and the Balearics. The statistical comparative analysis between the observed and the HIPOCAS fields highlights their very good agreement not only in terms of spatial and time distribution, but also in terms of total amount of precipitation. A principal component analysis is carried out, showing that the patterns derived from the HIPOCAS data largely capture the main characteristics of the observed field. Moreover, it is worth to note that the HIPOCAS patterns reproduce accurately the observed regional characteristics linked to the main orographic features of the study domain. The existence of high correlations between the hindcasted and observed principal component time series gives a measure of the model performance ability. An additional comparative study of the HIPOCAS winter precipitation with global reanalysis data (NCEP and ERA) is performed. This study reveals the important regional improvement in the characterization of the observed precipitation introduced by the HIPOCAS hindcast relative to the above global reanalyses. Such improvement is effective not only in terms of total amount values, but also in the spatial distribution, the observed field being much more realistically reproduced by HIPOCAS than by the global reanalysis data. (orig.)

  4. Validation of a homogeneous 41-year (1961-2001) winter precipitation hindcasted dataset over the Iberian Peninsula: assessment of the regional improvement of global reanalysis

    Science.gov (United States)

    Sotillo, M. G.; Martín, M. L.; Valero, F.; Luna, M. Y.

    2006-11-01

    A 44-year (1958-2001) homogeneous, Mediterranean, high-resolution atmospheric database was generated through dynamical downscaling within the HIPOCAS (Hindcast of Dynamic Processes of the Ocean and Coastal Areas of Europe) Project framework. This work attempts to provide a validation of the monthly winter HIPOCAS precipitation over the Iberian Peninsula and the Balearic Islands and to evaluate the potential improvement of these new hindcasted data versus global reanalysis datasets. The validation was performed through the comparative analysis with a precipitation database derived from 4,617 in situ stations located over Iberia and the Balearics. The statistical comparative analysis between the observed and the HIPOCAS fields highlights their very good agreement not only in terms of spatial and time distribution, but also in terms of total amount of precipitation. A principal component analysis is carried out, showing that the patterns derived from the HIPOCAS data largely capture the main characteristics of the observed field. Moreover, it is worth to note that the HIPOCAS patterns reproduce accurately the observed regional characteristics linked to the main orographic features of the study domain. The existence of high correlations between the hindcasted and observed principal component time series gives a measure of the model performance ability. An additional comparative study of the HIPOCAS winter precipitation with global reanalysis data (NCEP and ERA) is performed. This study reveals the important regional improvement in the characterization of the observed precipitation introduced by the HIPOCAS hindcast relative to the above global reanalyses. Such improvement is effective not only in terms of total amount values, but also in the spatial distribution, the observed field being much more realistically reproduced by HIPOCAS than by the global reanalysis data.

  5. Influence of acid and alkaline sources on optical, structural and photovoltaic properties of CdSe nanoparticles precipitated from aqueous solution

    Science.gov (United States)

    Coria-Monroy, C. Selene; Sotelo-Lerma, Mérida; Hu, Hailin

    2016-06-01

    CdSe is a widely researched material for photovoltaic applications. One of the most important parameters of the synthesis is the pH value, since it determines the kinetics and the mechanism of the reaction and in consequence, the optical and morphological properties of the products. We present the synthesis of CdSe in solution with strict control of pH and the comparison of ammonia and KOH as alkaline sources and diluted HCl as acid medium. CdSe formation was monitored with photoluminescence emission spectra (main peak in 490 nm, bandgap of CdSe nanoparticles). XRD patterns indicated that CdSe nanoparticles are mainly of cubic structure for ammonia and HCl, but the hexagonal planes appear with KOH. Product yield decreases with pH and also decreases with KOH at constant pH value since ammonia has a double function, as complexing agent and alkaline source. Changes in morphology were observed in SEM images as well with the different alkaline source. The effect of alkaline sources on photovoltaic performance of hybrid organic solar cells with CdSe and poly(3-hexylthiophene) as active layers was clearly observed, indicating the importance of synthesis conditions on optoelectronic properties of promising semiconductor nanomaterials for solar cell applications.

  6. Simultaneous chemical oxygen demand removal, methane production and heavy metal precipitation in the biological treatment of landfill leachate using acid mine drainage as sulfate resource.

    Science.gov (United States)

    Li, Yu-Long; Wang, Jin; Yue, Zheng-Bo; Tao, Wei; Yang, Hai-Bin; Zhou, Yue-Fei; Chen, Tian-Hu

    2017-07-01

    Biological treatment played an important role in the treatment of landfill leachate. In the current study, acid mine drainage (AMD) was used as a source of sulfate to strengthen the anaerobic treatment of landfill leachate. Effects of chemical oxygen demand (COD) and SO42- mass concentration ratio on the decomposition of organic matter, methane production and sulfate reduction were investigated and the microbial community was analyzed using the high throughout methods. Results showed that high removal efficiency of COD, methane production and heavy metal removal was achieved when the initial COD/SO42- ratio (based on mass) was set at 3.0. The relative abundance of anaerobic hydrogen-producing bacteria (Candidatus Cloacamonas) in the experimental group with the addition of AMD was significantly increased compared to the control. Abundance of hydrogenotrophic methanogens of Methanosarcina and Methanomassiliicoccus was increased. Results confirmed that AMD could be used as sulfate resource to strengthen the biological treatment of landfill leachate. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  7. Assessing the potential of fatty acids produced by filamentous fungi as feedstock for biodiesel production.

    Science.gov (United States)

    Rivaldi, Juan Daniel; Carvalho, Ana Karine F; da Conceição, Leyvison Rafael V; de Castro, Heizir F

    2017-11-26

    Increased costs and limited availability of traditional lipid sources for biodiesel production encourage researchers to find more sustainable feedstock at low prices. Microbial lipid stands out as feedstock replacement for vegetable oil to convert fatty acid esters. In this study, the potential of three isolates of filamentous fungi (Mucor circinelloides URM 4140, M. hiemalis URM 4144, and Penicillium citrinum URM 4126) has been assessed as single-cell oil (SCO) producers. M. circinelloides 4140 had the highest biomass concentration with lipid accumulation of up to 28 wt% at 120 hr of cultivation. The profile of fatty acids revealed a high content of saturated (SFA) and monounsaturated fatty acids (MUFA), including palmitic (C16:0, 33.2-44.1 wt%) and oleic (C18:1, 20.7-31.2 wt%) acids, with the absence of polyunsaturated fatty acids (PUFA) having more than four double bonds. Furthermore, the predicted properties of biodiesel generated from synthesized SCOs have been estimated by using empirical models which were in accordance with the limits imposed by the USA (ASTM D6715), European Union (EN 14214), and Brazilian (ANP 45/2014) standards. These results suggest that the assessed filamentous fungus strains can be considered as alternative feedstock sources for high-quality biofuel production.

  8. 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.

  9. Recent advances in the risk assessment of melamine and cyanuric acid in animal feed.

    Science.gov (United States)

    Dorne, Jean Lou; Doerge, Daniel R; Vandenbroeck, Marc; Fink-Gremmels, Johanna; Mennes, Wim; Knutsen, Helle K; Vernazza, Francesco; Castle, Laurence; Edler, Lutz; Benford, Diane

    2013-08-01

    Melamine can be present at low levels in food and feed mostly from its legal use as a food contact material in laminates and plastics, as a trace contaminant in nitrogen supplements used in animal feeds, and as a metabolite of the pesticide cyromazine. The mechanism of toxicity of melamine involves dose-dependent formation of crystals with either endogenous uric acid or a structural analogue of melamine, cyanuric acid, in renal tubules resulting in potential acute kidney failure. Co-exposure to melamine and cyanuric acid in livestock, fish, pets and laboratory animals shows higher toxicity compared with melamine or cyanuric acid alone. Evidence for crystal formation between melamine and other structural analogs i.e. ammelide and ammeline is limited. Illegal pet food adulterations with melamine and cyanuric acid and adulteration of milk with melamine resulted in melamine-cyanuric acid crystals, kidney damage and deaths of cats and dogs and melamine-uric acid stones, hospitalisation and deaths of children in China respectively. Following these incidents, the tolerable daily intake for melamine was re-evaluated by the U.S. Food and Drug Administration, the World Health Organisation, and the Scientific Panel on Contaminants in the Food Chain of the European Food Safety Authority (EFSA). This review provides an overview of toxicology, the adulteration incidents and risk assessments for melamine and its structural analogues. Particular focus is given to the recent EFSA risk assessment addressing impacts on animal and human health of background levels of melamine and structural analogues in animal feed. Recent research and future directions are discussed. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. Bacterially mediated precipitation in marine stromatolites.

    Science.gov (United States)

    Paerl, H W; Steppe, T F; Reid, R P

    2001-02-01

    Stromatolites are laminated, lithified (CaCO3) sedimentary deposits formed by precipitation and/or sediment accretion by cyanobacterial-bacterial mat communities. Stromatolites have been associated with these communities as far back as the Precambrian era some 2+ billion years ago. The means by which microbial communities mediate the precipitation processes have remained unclear, and are the subject of considerable debate and speculation. Two alternative explanations for microbially mediated precipitation include: (i) cyanobacterial photosynthesis increases pH in a system supersaturated in respect of CaCO3, resulting in CaCO3 precipitation and then laminated lithification, and (ii) decomposition of cyanobacterial extracellular organic matter (e.g. sheaths, mucilage and organic acids) by microheterotrophs leads to release of organic-bound Ca2+ ions and CaCO3 precipitation. We evaluated these explanations by examining metabolically active, lithifying stromatolitic mat communities from Highborne Cay, Bahamas, using microautoradiography. Microautoradiographic detection of 14CO2 fixation and 3H organic matter (D-glucose and an amino acid mixture) utilization by photosynthetically active cyanobacteria and microheterotrophs, combined with community-level uptake experiments, indicate that bacteria, rather than cyanobacteria are the dominant sites of CaCO3 deposition. In the oligotrophic waters in which stromatolites exist, microheterotrophs are reliant on the photosynthetic community as a main source of organic matter. Therefore, autotrophic production indirectly controls microbially mediated precipitation and stromatolite formation in these shallow marine environments.

  11. Quantitative assessment of moniliformin in cereals via alternative precipitation pathways, aided by LC-LIT-MS and LC-Q-TOF-MS.

    Science.gov (United States)

    Lim, Chee Wei; Lai, Kit Yee; Yeo, Jie Fang; Tai, Siew Hoon; Chan, Sheot Harn

    2015-05-01

    The availability of a simple chemical precipitation workflow aided by targeted and untargeted mass spectrometry would provide an accurate diagnostic platform for the direct determination of moniliformin in cereals for food safety control. In-house method validation was performed at six concentration levels of 8, 40, 80, 200, 400, and 600 ng g(-1) in cereal flours of wheat, corn, rye, oats and barley. Spiking experiments were made at three concentration levels of 20, 40 and 100 ng g(-1). Protein precipitation and "PHREE" column cleanup strategy provided recoveries of 81-108% for all cereals matrices using external calibrants. "PHREE" purification provided significant (p cereals becomes available to support prospective regulatory function. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Regional climate assessment of precipitation and temperature in Southern Punjab (Pakistan) using SimCLIM climate model for different temporal scales

    Science.gov (United States)

    Amin, Asad; Nasim, Wajid; Mubeen, Muhammad; Sarwar, Saleem; Urich, Peter; Ahmad, Ashfaq; Wajid, Aftab; Khaliq, Tasneem; Rasul, Fahd; Hammad, Hafiz Mohkum; Rehmani, Muhammad Ishaq Asif; Mubarak, Hussani; Mirza, Nosheen; Wahid, Abdul; Ahamd, Shakeel; Fahad, Shah; Ullah, Abid; Khan, Mohammad Nauman; Ameen, Asif; Amanullah; Shahzad, Babar; Saud, Shah; Alharby, Hesham; Ata-Ul-Karim, Syed Tahir; Adnan, Muhammad; Islam, Faisal; Ali, Qazi Shoaib

    2018-01-01

    Unbalanced climate during the last decades has created spatially alarming and destructive situations in the world. Anomalies in temperature and precipitation enhance the risks for crop production in large agricultural region (especially the Southern Punjab) of Pakistan. Detailed analysis of historic weather data (1980-2011) record helped in creating baseline data to compare with model projection (SimCLIM) for regional level. Ensemble of 40 GCMs used for climatic projections with greenhouse gas (GHG) representative concentration pathways (RCP-4.5, 6.0, 8.5) was selected on the baseline comparison and used for 2025 and 2050 climate projection. Precipitation projected by ensemble and regional weather observatory at baseline showed highly unpredictable nature while both temperature extremes showed 95 % confidence level on a monthly projection. Percentage change in precipitation projected by model with RCP-4.5, RCP-6.0, and RCP-8.5 showed uncertainty 3.3 to 5.6 %, 2.9 to 5.2 %, and 3.6 to 7.9 % for 2025 and 2050, respectively. Percentage change of minimum temperature from base temperature showed that 5.1, 4.7, and 5.8 % for 2025 and 9.0, 8.1, and 12.0 % increase for projection year 2050 with RCP-4.5, 6.0, and 8.5 and maximum temperature 2.7, 2.5, and 3.0 % for 2025 and 4.7, 4.4, and 6.4 % for 2050 will be increased with RCP-4.5, 6.0, and 8.5, respectively. Uneven increase in precipitation and asymmetric increase in temperature extremes in future would also increase the risk associated with management of climatic uncertainties. Future climate projection will enable us for better risk management decisions.

  13. Avaliação de estimativas de campos de precipitação para modelagem hidrológica distribuída Assessment of estimated precipitation fields for distributed hydrologic modeling

    Directory of Open Access Journals (Sweden)

    Adriano Rolim da Paz

    2011-03-01

    produces skill scores denoting the ability of the estimated precipitation field in reproducing the occurrence of observed precipitation along the time; (ii the time integrated analysis generates maps of skill scores showing the reliability of the precipitation estimates in each pixel. As an example of application, the estimated precipitation climatology of the CPTEC/COLA global circulation model over the Rio Grande basin is assessed. Using five different skill scores, the proposed method identified seasonal variations and spatial patterns in the performance of the estimated precipitation fields in relation to precipitation fields derived from pluviometers measurement.

  14. Catalyzed precipitation in aluminum

    Science.gov (United States)

    Mitlin, David

    The work reported in Chapter 1 concerned the influence of Si on the precipitation of theta' (metastable Al2Cu) during the isothermal aging of Al-2Cu-1Si (wt. %). The binary alloys Al-2Cu and Al-1Si were studied for comparison. Only two precipitate phases were detected: pure Si in Al-Si and Al-Cu-Si, and theta' (metastable Al 2Cu) in Al-Cu and Al-Cu-Si. On aging the ternary, Si precipitates first, and provides heterogeneous sites to nucleate theta'. As a consequence, the density of theta' precipitates in Al-Cu-Si is much higher than in the binary Al-Cu. Also, the theta ' precipitates in the ternary alloy have lower aspect ratio (at given particle size) and lose coherence on their broad faces at a slower rate. The principal focus of Chapter 2 is to explain precipitation in Al-lat.%Si-lat%Ge. The microstructure is characterized using conventional and high resolution transmission electron microscopy, as well as energy dispersive X-ray spectroscopy. The first precipitates to come out of solid solution have a cube-cube orientation relationship with the matrix. High resolution TEM demonstrated that all the precipitates start out, and remain multiply twinned throughout the aging treatment. There is a variation in the stoichiometry of the precipitates, with the mean composition being Si-44.5at%Ge. It is also shown that in Al-Si-Ge it is not possible to achieve satisfactory hardness through a conventional heat treatment. This result is explained in terms of sluggish precipitation of the diamond-cubic Si-Ge phase coupled with particle coarsening. The purpose of Chapters 3 and 4 is to explain these properties in terms of the role that the Si-Ge additions have on modifying the conventional Al-Cu aging sequence. In both AlCu and AlCuSiGe the room temperature microstructure consists of both GP zones and theta″ precipitates. Upon aging at 190°C Al-Cu displays the well known precipitation sequence; the slow dissolution of GP zones and theta″ and the gradual formation of theta

  15. Precipitation Recycling and the Vertical Distribution of Local and Remote Sources of Water for Precipitation

    Science.gov (United States)

    Bosilovich, Michael G.; Atlas, Robert (Technical Monitor)

    2002-01-01

    Precipitation recycling is defined as the amount of water that evaporates from a region that precipitates within the same region. This is also interpreted as the local source of water for precipitation. In this study, the local and remote sources of water for precipitation have been diagnosed through the use of passive constituent tracers that represent regional evaporative sources along with their transport and precipitation. We will discuss the differences between this method and the simpler bulk diagnostic approach to precipitation recycling. A summer seasonal simulation has been analyzed for the regional sources of the United States Great Plains precipitation. While the tropical Atlantic Ocean (including the Gulf of Mexico) and the local continental sources of precipitation are most dominant, the vertically integrated column of water contains substantial water content originating from the Northern Pacific Ocean, which is not precipitated. The vertical profiles of regional water sources indicate that local Great Plains source of water dominates the lower troposphere, predominantly in the PBL. However, the Pacific Ocean source is dominant over a large portion of the middle to upper troposphere. The influence of the tropical Atlantic Ocean is reasonably uniform throughout the column. While the results are not unexpected given the formulation of the model's convective parameterization, the analysis provides a quantitative assessment of the impact of local evaporation on the occurrence of convective precipitation in the GCM. Further, these results suggest that local source of water is not well mixed throughout the vertical column.

  16. Assessing the potential of satellite-based precipitation estimates for flood frequency analysis in ungauged or poorly gauged tributaries of China's Yangtze River basin

    Science.gov (United States)

    Gao, Zhen; Long, Di; Tang, Guoqiang; Zeng, Chao; Huang, Jiesheng; Hong, Yang

    2017-07-01

    Flood frequency analysis (FFA) is critical for water resources engineering projects, particularly the design of hydraulic structures such as dams and reservoirs. However, it is often difficult to implement FFA in ungauged or poorly gauged basins because of the lack of consistent and long-term records of streamflow observations. The objective of this study was to evaluate the utility of satellite-based precipitation estimates for performing FFA in two presumably ungauged tributaries, the Jialing and Tuojiang Rivers, of the upper Yangtze River. Annual peak flow series were simulated using the Coupled Routing and Excess STorage (CREST) hydrologic model. Flood frequency was estimated by fitting the Pearson type III distribution of both observed and modeled streamflow with historic floods. Comparison of satellite-based precipitation products with a ground-based daily precipitation dataset for the period 2002-2014 reveals that 3B42V7 outperformed 3B42RT. The 3B42V7 product also shows consistent reliability in streamflow simulation and FFA (e.g., relative errors -20%-5% in the Jialing River). The results also indicate that complex terrain, drainage area, and reservoir construction are important factors that impact hydrologic model performance. The larger basin (156,736 km2) is more likely to produce satisfactory results than the small basin (19,613 km2) under similar circumstances (e.g., Jialing/Tuojiang calibrated by 3B42V7 for the calibration period: NSCE = 0.71/0.56). Using the same calibrated parameter sets from the entire Jialing River basin, the 3B42V7/3B42RT-driven hydrologic model performs better for two tributaries of the Jialing River (e.g., for the calibration period, NSCE = 0.71/0.60 in the Qujiang River basin and 0.54/0.38 in the Fujiang River basin) than for the upper mainstem of the Jialing River (NSCE = 0.34/0.32), which has more cascaded reservoirs with all these tributaries treated as ungauged basins for model validation. Overall, this study underscores

  17. Assessment of the effect of acid deposition on forest soils in Stockholm County

    Energy Technology Data Exchange (ETDEWEB)

    Odlare, M. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Forest Soils

    1997-05-01

    The objective of this study was to assess how the acidity in the upper layer of forest soils in Stockholm County is affected by acid deposition. The acidity balance in a long-term perspective was assessed by a steady state mass balance model approach. The model involved a procedure where all significant acidifying processes were weighted against the neutralizing process. If the acidity balance reached a value higher than zero, the critical load of the soil has been exceeded. The acidity balance was calculated for 91 forest sample sites throughout Stockholm County. Two different data sets were used: 22 sites from the National Survey of Forest Soils and Vegetation, and 69 sites from the Forestry Board. The acidity balance was assessed in relation to four different scenarios: (1) Present deposition, whole tree harvesting; (2) Present deposition, stem harvesting; (3) 30% reduction in deposition, whole tree harvesting; and (4) 30% reduction in deposition, stem harvesting. A majority of the sites reached a positive acidity balance in all scenarios, i.e. they had exceeded the critical load. However, the values decreased with stem harvesting and 30% reduction in deposition. A 30% reduction together with stem harvesting gave the result that 59% of the sites from the National Survey of Forest Soils and Vegetation and 55% of the sites from the forestry Board achieved a positive balance. That is, almost half of the sites did not exceed the critical load. It is therefore likely that scenario 4 is close to the 50 percentile of exceeding the critical load. After studying the different parameters in the model, it seems that the most important factors for the difference between sites are base cation uptake and weathering. The sample sites that did not reach excessive levels had a low base cation uptake in comparison with other parameters and a relatively high weathering rate. It seems that acidification on the 91 sample sites is less dependent on acid deposition and more on tree

  18. Chemical and biological status of lakes and streams in the upper midwest: assessment of acidic deposition effects

    Science.gov (United States)

    Wiener, J.G.; Eilers, J.M.

    1987-01-01

    Many lakes in three areas in the Upper Midwest - northeastern Minnesota, northern Wisconsin, and the Upper Peninsula of Michigan - have low acid neutralizing capacity (ANC) and may be susceptible to change by acidic deposition. Northcentral Wisconsin and the Upper Peninsula of Michigan together contain about 150-300 acidic lakes (ANC ≤ 0), whereas none have been found in Minnesota. These acidic lakes are precipitation-dominated, Clearwater seepage lakes having small surface area, shallow depth, and low concentrations of dissolved organic carbon. The spatial distribution of these acidic lakes parallels a west to east gradient of increasing sulfate and hydrogen ion deposition. Several of these acidic lakes exhibit chemical characteristics and biological changes consistent with those observed elsewhere in waters reported to be acidified by acidic deposition. However, an hypothesis of recent lake acidification is not supported by analyses of either historical chemical data or diatom remains in lake sediments, and natural sources of acidity and alternative ecological processes have not been conclusively eliminated as causative factors. Streams in this three-state region have high ANC and appear to be insensitive to acidic deposition. The species richness and composition of lacustrine fish communities in the region are partly related to pH and associated chemical factors. Sport fishes considered acid-sensitive and of primary concern with regard to acidification include walleye, smallmouth bass, and black crappie. The fishery in at least one lake, Morgan Lake in Wisconsin (pH 4.6), may have declined because of acidification. Given the general lack of quantitative fishery data for acidic Wisconsin and Michigan lakes, however, more general conclusions concerning impacts or the absence of impacts of acidification on the region's fishery resources are not possible.

  19. Sono-precipitation of Ag2CrO4-C composite enhanced by carbon-based materials (AC, GO, CNT and C3N4) and its activity in photocatalytic degradation of acid orange 7 in water.

    Science.gov (United States)

    Azami, Mina; Haghighi, Mohammad; Allahyari, Somaiyeh

    2018-01-01

    Enhancing the photocatalytic activity of Ag 2 CrO 4 with coupled carbon-based materials like activated carbon, graphene oxide, carbon nanotubes and carbon nitride has been investigated in removal of Acid Orange 7 from wastewater. Sono precipitated Ag 2 CrO 4 -C composite based photocatalysts were characterized by XRD, BET, FESEM, FTIR and UV-vis DRS and the photocatalytic activity of theses samples was evaluated in terms of degradation amount of acid orange 7 under visible light irradiations. BET analysis showed that with addition of carbon based materials, the specific surface area of the Ag 2 CrO 4 -C composite increased. XRD analysis indicated that the crystallinity of Ag 2 CrO 4 peaks decreased after addition of all studied carbon-based materials and C 3 N 4 has lowered the crystallinity of Ag 2 CrO 4 less than others. Higher crystallinity has the positive effect of higher photocatalytic activity because among above mentioned composites, Ag 2 CrO 4 -C 3 N 4 photocatalyst exhibited higher photocatalytic activity and stability under visible light irradiations. DRS analysis confirmed good match of electronic structures of Ag 2 CrO 4 and C 3 N 4 . On the other hand Ag 2 CrO 4 and C 3 N 4 formed heterojunction which separates photo-generated electron-hole pairs effectively. Also evaluation of photocatalytic reaction in various operating parameters showed Ag 2 CrO 4 -C 3 N 4 had the highest photocatalytic activity in neutral pH and 1g/L of catalyst loading. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Extraction and Separation of Vitisin D, Ampelopsin B and cis-Vitisin A from Iris lactea Pall. var. chinensis (Fisch.) Koidz by Alkaline Extraction-Acid Precipitation and High-Speed Counter-Current Chromatography.

    Science.gov (United States)

    Lv, Huanhuan; Zhou, Wenna; Wang, Xiaoyan; Wang, Zhenhua; Suo, Yourui; Wang, Honglun

    2016-01-01

    Naturally occurring oligostilbenes are receiving more attention because they exhibit several beneficial effects for health, including hepatoprotective, antitumor, anti-adipogenic, antioxidant, antiaging, anti-inflammatory, anti-microbial, antiviral, immunosuppressive and neuroprotective activities. Thus, they could be of some potentially therapeutic values for several diseases. In this study, we adopted the alkaline extraction-acid precipitation (AEAP) method for extraction of oligostilbenes from the seed kernel of Iris lactea Then, the high-speed counter-current chromatography (HSCCC) was used for preparative isolation and purification of oligostilbenes from the AEAP extracts. Finally, three oligostilbenes, namely vitisin D (73 mg), ampelopsin B (25 mg) and cis-vitisin A (16 mg), were successfully fractionated by HSCCC with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (2:5:3:6, v/v/v/v) from 300 mg of the AEAP extracts in ∼ 190 min. The purities of the three isolated oligostilbenes were all over 95.0% as analyzed by high performance liquid chromatography. They all were isolated from I. lacteal for the first time.The method of AEAP for the preparation of the oligostilbene-enriched crude sample was simple, and the HSCCC technique for the isolation and purification of oligostilbenes was efficient. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Extraction and Separation of Vitisin D, Ampelopsin B and cis-Vitisin A from Iris lactea Pall. var. chinensis (Fisch.) Koidz by Alkaline Extraction–Acid Precipitation and High-Speed Counter-Current Chromatography

    Science.gov (United States)

    Lv, Huanhuan; Zhou, Wenna; Wang, Xiaoyan; Wang, Zhenhua; Suo, Yourui; Wang, Honglun

    2016-01-01

    Naturally occurring oligostilbenes are receiving more attention because they exhibit several beneficial effects for health, including hepatoprotective, antitumor, anti-adipogenic, antioxidant, antiaging, anti-inflammatory, anti-microbial, antiviral, immunosuppressive and neuroprotective activities. Thus, they could be of some potentially therapeutic values for several diseases. In this study, we adopted the alkaline extraction–acid precipitation (AEAP) method for extraction of oligostilbenes from the seed kernel of Iris lactea. Then, the high-speed counter-current chromatography (HSCCC) was used for preparative isolation and purification of oligostilbenes from the AEAP extracts. Finally, three oligostilbenes, namely vitisin D (73 mg), ampelopsin B (25 mg) and cis-vitisin A (16 mg), were successfully fractionated by HSCCC with a two-phase solvent system composed of n-hexane–ethyl acetate–methanol–water (2:5:3:6, v/v/v/v) from 300 mg of the AEAP extracts in ∼190 min. The purities of the three isolated oligostilbenes were all over 95.0% as analyzed by high performance liquid chromatography. They all were isolated from I. lactea for the first time. The method of AEAP for the preparation of the oligostilbene-enriched crude sample was simple, and the HSCCC technique for the isolation and purification of oligostilbenes was efficient. PMID:26847919

  2. Assessment of the environmental aspects of the DOE phosphoric acid fuel cell program

    Science.gov (United States)

    Lundblad, H. L.; Cavagrotti, R. R.

    1983-01-01

    The likely facets of a nationwide phosphoric acid fuel cell (PAFC) power plant commercial system are described. The beneficial and adverse environmental impacts produced by the system are assessed. Eleven specific system activities are characterized and evaluated. Also included is a review of fuel cell technology and a description of DOE's National Fuel Cell Program. Based on current and reasonably foreseeable PAFC characteristics, no environmental or energy impact factor was identified that would significantly inhibit the commercialization of PAFC power plant technology.

  3. Environmental Life Cycle Assessment of Diets with Improved Omega-3 Fatty Acid Profiles

    OpenAIRE

    Coelho, Carla R. V.; Pernollet, Franck; van der Werf, Hayo M. G.

    2016-01-01

    A high incidence of cardiovascular disease is observed worldwide, and dietary habits are one of the risk factors for these diseases. Omega-3 polyunsaturated fatty acids in the diet help to prevent cardiovascular disease. We used life cycle assessment to analyse the potential of two strategies to improve the nutritional and environmental characteristics of French diets: 1) modifying diets by changing the quantities and proportions of foods and 2) increasing the omega-3 contents in diets by rep...

  4. Behaviour of the pH adjustment, Ion exchange and concentrate precipitation stages in the acid leaching of uranium phosphate ores; Tratamiento de disoluciones de lixiviacion de minerales de uranio en presencia de fosfatos. Comportamiento en las etapas de ajuste de PH, cambio de ion y precipitacion de concentrados

    Energy Technology Data Exchange (ETDEWEB)

    Estrada Aguilar, J.; Uriarte Hueda, A.

    1962-07-01

    The uranium recovery from acid leach solutions of uranium-phosphate ores has been studied. Relations have been found between the solution characteristics and the results obtained at different stages of the process. The following data can thus be predicted: solids to remove and uranium recovery in the pH adjustment stage, uranium capacity of the resin, more suitable eluating agent, elution velocity and uranium concentration in the eluate in the ion exchange stage, and composition of the concentrate produced by direct precipitation of the eluate in the concentrate precipitation stage. (Author) 8 refs.

  5. Trends of selected malformations in relation to folic acid recommendations and fortification: an international assessment.

    LENUS (Irish Health Repository)

    Botto, Lorenzo D

    2006-10-01

    Two crucial issues relative to the benefits and impact of folic acid in the prevention of birth defects are whether supplementation recommendations alone, without fortification, are effective in reducing the population-wide rates of neural tube defects (NTDs), and whether such policies can reduce the occurrence of other birth defects. Using data from 15 registries, we assessed rates and trends of 14 major defects, including NTDs, in areas with official recommendations or fortification to assess the effectiveness of recommendations and fortification on a wide range of major birth defects.

  6. 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....

  7. Storage Gage Precipitation Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A storage gage is a precipitation gage that requires reading and maintenance only monthly or seasonal intervals. This library includes reports from such gages,...

  8. Assessment of Two Types of Interior Nudging for High-Resolution Simulations during Oahu, Hawaii's 40-Days and 40-Nights Extreme Precipitation Event

    Science.gov (United States)

    Holloway, C. T.; Chu, P. S.

    2015-12-01

    Dynamical Downscaling for climate length simulations is a process where large-scale atmospheric fields are input to a regional climate model (RCM) to explicitly simulate regional and local- scale climate features that are not captured by the large-scale model. One such example of features not being captured occurs over the Central North Pacific's Hawaiian Island chain, where most large-scale models poorly resolve the small islands and their complex topographies, which have a significant influence on the regions winds, temperature, and precipitation. For the dynamical downscaling procedure to realistically resolve the small Hawaiian Islands we must use three nested, where the innermost domain centered over Oahu, Hawaii has a grid resolution of 1.1 km. Also during the dynamical downscaling process RCMs interior solution tends to drift away from the large-scale driving fields resulting in significant RCM temperature and precipitation biases especially during extreme events. Two possible solutions developed to allow the RCM to retain the large-scale features, yet still generate the small scale variabilities are analysis and spectral nudging. Here, we examine the performance of both analysis and spectral nudging in the downscaling of NCEPII reanalysis data during the extreme 2-month wet period known as the 40-days and 40-nights of rain over the Hawaiian Islands using the Advanced Research Weather and Forecasting (WRF-ARW) model. The simulations are compared against land based observations acquired from the National Climate Data Center (NCDC) to show the differences for 2-m temperature and precipitation between the nudging techniques and observations from Oahu, Hawaii.

  9. Use of mineral/solution equilibrium calculations to assess the potential for carnotite precipitation from groundwater in the Texas Panhandle, USA

    Science.gov (United States)

    Ranalli, Anthony J.; Yager, Douglas B.

    2016-01-01

    This study investigated the potential for the uranium mineral carnotite (K2(UO2)2(VO4)2·3H2O) to precipitate from evaporating groundwater in the Texas Panhandle region of the United States. The evolution of groundwater chemistry during evaporation was modeled with the USGS geochemical code PHREEQC using water-quality data from 100 groundwater wells downloaded from the USGS National Water Information System (NWIS) database. While most modeled groundwater compositions precipitated calcite upon evaporation, not all groundwater became saturated with respect to carnotite with the system open to CO2. Thus, the formation of calcite is not a necessary condition for carnotite to form. Rather, the determining factor in achieving carnotite saturation was the evolution of groundwater chemistry during evaporation following calcite precipitation. Modeling in this study showed that if the initial major-ion groundwater composition was dominated by calcium-magnesium-sulfate (>70 precent Ca + Mg and >50 percent SO4 + Cl) or calcium-magnesium-bicarbonate (>70 percent Ca + Mg and calcium was greater than the carbonate alkalinity (2mCa+2 > mHCO3− + 2mCO3−2) carnotite saturation was achieved. If, however, the initial major-ion groundwater composition is sodium-bicarbonate (varying amounts of Na, 40–100 percent Na), calcium-sodium-sulfate, or calcium-magnesium-bicarbonate composition (>70 percent HCO3 + CO3) and following the precipitation of calcite, the concentration of calcium was less than the carbonate alkalinity (2mCa+2 < mHCO3- + 2mCO3−2) carnotite saturation was not achieved. In systems open to CO2, carnotite saturation occurred in most samples in evaporation amounts ranging from 95 percent to 99 percent with the partial pressure of CO2 ranging from 10−3.5 to 10−2.5 atm. Carnotite saturation occurred in a few samples in evaporation amounts ranging from 98 percent to 99 percent with the partial pressure of CO2 equal to 10−2.0 atm. Carnotite

  10. Uncertainty in determining extreme precipitation thresholds

    Science.gov (United States)

    Liu, Bingjun; Chen, Junfan; Chen, Xiaohong; Lian, Yanqing; Wu, Lili

    2013-10-01

    Extreme precipitation events are rare and occur mostly on a relatively small and local scale, which makes it difficult to set the thresholds for extreme precipitations in a large basin. Based on the long term daily precipitation data from 62 observation stations in the Pearl River Basin, this study has assessed the applicability of the non-parametric, parametric, and the detrended fluctuation analysis (DFA) methods in determining extreme precipitation threshold (EPT) and the certainty to EPTs from each method. Analyses from this study show the non-parametric absolute critical value method is easy to use, but unable to reflect the difference of spatial rainfall distribution. The non-parametric percentile method can account for the spatial distribution feature of precipitation, but the problem with this method is that the threshold value is sensitive to the size of rainfall data series and is subjected to the selection of a percentile thus make it difficult to determine reasonable threshold values for a large basin. The parametric method can provide the most apt description of extreme precipitations by fitting extreme precipitation distributions with probability distribution functions; however, selections of probability distribution functions, the goodness-of-fit tests, and the size of the rainfall data series can greatly affect the fitting accuracy. In contrast to the non-parametric and the parametric methods which are unable to provide information for EPTs with certainty, the DFA method although involving complicated computational processes has proven to be the most appropriate method that is able to provide a unique set of EPTs for a large basin with uneven spatio-temporal precipitation distribution. The consistency between the spatial distribution of DFA-based thresholds with the annual average precipitation, the coefficient of variation (CV), and the coefficient of skewness (CS) for the daily precipitation further proves that EPTs determined by the DFA method

  11. Caracterização de concentrado protéico de folhas de mandioca obtido por precipitação com calor e ácido Characterization of cassava leaf protein concentrate obtained by heat and acid precipitation

    Directory of Open Access Journals (Sweden)

    Cláudia de Fátima Modesti

    2007-09-01

    Full Text Available As folhas de mandioca apresentam um teor elevado de proteínas, todavia sua digestibilidade é baixa. A produção de concentrado protéico de folhas de mandioca (CPFM permite a utilização das proteínas das folhas com um reduzido teor de fibras e melhor qualidade protéica. Neste trabalho, analisaram-se características químicas de CPFM obtidos por diferentes formas de precipitação, com calor e com ácido. Os CPFM praticamente não apresentaram diferenças na composição centesimal. O nível de proteína dos CPFM aumentou 57,72% em comparação ao da farinha de folhas de mandioca (FFM. Os rendimentos de extração das proteínas também foram semelhantes para os CPFM. O teor de Fe dos CPFM foi mais elevado quando comparado com o da FFM. A FFM apresentou absorção de água e de óleo mais elevada que os CPFM, mas, entre os tipos de CPFM, os resultados foram semelhantes. A mínima solubilidade de nitrogênio da FFM e dos CPFM foi observada em pH entre 3 e 5. Verificou-se que a FFM apresentou uma capacidade de formação e estabilidade de espuma mais elevada que os CPFM. Tanto a FFM quanto os CPFM não apresentaram boa estabilidade de emulsão.Cassava leaves have a high content of protein of low digestibility. The production of cassava leaf protein concentrate (CLPC enables cassava leaf protein to be used with a reduced fiber content and better protein quality. This work involved an investigation of the chemical characteristics of CLPC produced by different forms of precipitation, using heat and acid. No significant differences were found in the centesimal composition of the CLPC. The protein content in CLPC was 57.72% higher than in cassava leaf flour (CLF. Both types of CLPC precipitation also yielded similar protein concentrations. The CLPC Fe content was higher than that of the CLF. The CLF presented higher water and oil absorption than did CLPC, although the CLPC extracted by the two methods showed similar results. The lowest nitrogen

  12. Lead exposure assessment from study near a lead-acid battery factory in China.

    Science.gov (United States)

    Chen, Laiguo; Xu, Zhencheng; Liu, Ming; Huang, Yumei; Fan, Ruifang; Su, Yanhua; Hu, Guocheng; Peng, Xiaowu; Peng, Xiaochun

    2012-07-01

    The production of lead-acid battery in China covered about one-third of the world total output and there are more than 2000 lead-acid battery factories. They may cause the major environment lead pollution. Blood lead levels of several hundreds of residents were over 100 μg/L due to the waste discharges from a lead-acid battery factory in Heyuan, Guangdong province. This study aimed to find out the environmental lead sources, the human lead exposure pathways, and the amplitudes from a lead-acid battery factory. The study results showed that lead levels in soil, dust, tree leaves and human blood declined with the distances increased from the production site. Twenty nine of 32 participants had blood lead levels of over 100 μg/L with an exceptional high value of 639 μg/L for one child. This result suggested that the lead-acid battery production from this factory has caused the elevated lead levels in its neighboring environment and residents. Dust intake was the dominant exposure pathway for humans (over 90%). The lead levels found in adult and toddler (6.19 and 50.1 μg/kg/d, respectively) in the polluted area were far higher than the provisional tolerable weekly intake (PTWI) of 25 μg/kg body weight (translated into 3.5 μg/kg/d), which was established by the joint FAO/WHO Expert Committee. Blood lead levels within the family members were strongly correlated with the house dust lead levels. Our results in this study suggested that further studies in this area should be performed to assess human exposure and relevant human health risks from living close to lead-acid battery factories. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Exposure assessment of food preservatives (sulphites, benzoic and sorbic acid) in Austria.

    Science.gov (United States)

    Mischek, Daniela; Krapfenbauer-Cermak, Christine

    2012-01-01

    An exposure assessment was performed to estimate the potential intake of preservatives in the Austrian population. Food consumption data of different population groups, such as preschool children aged 3-6 years, female and male adults aged 19-65 years were used for calculation. Levels of the preservatives in food were derived from analyses conducted from January 2007 to August 2010. Dietary intakes of the preservatives were estimated and compared to the respective acceptable daily intakes (ADIs). In the average-intake scenario, assuming that consumers randomly consume food products that do or do not contain food additives, estimated dietary intakes of all studied preservatives are well below the ADI for all population groups. Sulphite exposure accounted for 34%, 84% and 89% of the ADI in preschool children, females and males, respectively. The mean estimated daily intake of benzoic acid was 32% (preschool children), 31% (males) and 36% (females) of the ADI. Sorbic acid intakes correspond to 7% of the ADI in preschool children and 6% of the ADI in adults. In the high-intake scenario assuming that consumers always consume food products that contain additives and considering a kind of brand loyalty of consumers, the ADI is exceeded for sulphites among adults (119 and 124%, respectively). Major contributors to the total intake of sulphites were wine and dried fruits for adults. Mean estimated dietary intakes of benzoic acid exceeded the ADI in all population groups, 135% in preschool children, 124% in females and 118% of the ADI in males, respectively. Dietary intakes of sorbic acid are well below the ADI, accounting for a maximum of 30% of the ADI in preschool children. The highest contributors to benzoic and sorbic acid exposure were fish and fish products mainly caused by high consumption data of this large food group, including also mayonnaise-containing fish salads. Other important sources of sorbic acid were bread, buns and toast bread and fruit and vegetable

  14. Trends in the precipitation and crystallization behavior of supersaturated aqueous solutions of poorly water-soluble drugs assessed using synchrotron radiation.

    Science.gov (United States)

    Raina, Shweta A; Van Eerdenbrugh, Bernard; Alonzo, David E; Mo, Huaping; Zhang, Geoff G Z; Gao, Yi; Taylor, Lynne S

    2015-06-01

    Amorphous materials are high-energy solids that can potentially enhance the bioavailability of poorly soluble compounds. A major impediment to their widespread use as a formulation platform is the tendency of amorphous materials to crystallize. The aim of this study was to evaluate the relative crystallization tendency of six structural analogues belonging to the dihydropyridine class, in an aqueous environment in the absence and presence of polymers, using wide-angle X-ray scattering synchrotron radiation and polarized light microscopy. The crystallization behavior of precipitates generated from supersaturated solutions of the active pharmaceutical ingredients was found to be highly variable ranging from immediate to several hours in the absence of polymers. Polymers with intermediate hydrophilicity/hydrophobicity were found to substantially delay crystallization, whereas strongly hydrophilic or hydrophobic polymers were largely ineffective. Nuclear magnetic resonance spectroscopy experiments supported the supposition that polymers need to have affinity for both the drug-rich precipitate and the aqueous phase in order to be effective crystallization inhibitors. This study highlights the variability in the crystallization tendency of different compounds and provides insight into the mechanism of inhibition by polymeric additives. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  15. Reference values assessment in a Mediterranean population for small dense low-density lipoprotein concentration isolated by an optimized precipitation method

    Directory of Open Access Journals (Sweden)

    Fernández-Cidón B

    2017-06-01

    Full Text Available Bárbara Fernández-Cidón,1–3 Ariadna Padró-Miquel,1 Pedro Alía-Ramos,1 María José Castro-Castro,1 Marta Fanlo-Maresma,4 Dolors Dot-Bach,1 José Valero-Politi,1 Xavier Pintó-Sala,4 Beatriz Candás-Estébanez1 1Clinical Laboratory, Hospital Universitari de Bellvitge, L’Hospitalet de Llobregat, Spain; 2Department of Biochemistry, Molecular Biology and Biomedicine, Autonomous University of Barcelona (UAB, Barcelona, Spain; 3Department of Pharmacotherapy, Pharmacogenetics and Pharmaceutical Technology, Institut d’Investigació Biomèdica de Bellvitge (IDIBELL, L’Hospitalet de Llobregat, Spain; 4Cardiovascular Risk Unit, Hospital Universitari de Bellvitge, L’Hospitalet de Llobregat, Spain Background: High serum concentrations of small dense low-density lipoprotein cholesterol (sd-LDL-c particles are associated with risk of cardiovascular disease (CVD. Their clinical application has been hindered as a consequence of the laborious current method used for their quantification. Objective: Optimize a simple and fast precipitation method to isolate sd-LDL particles and establish a reference interval in a Mediterranean population. Materials and methods: Forty-five serum samples were collected, and sd-LDL particles were isolated using a modified heparin-Mg2+ precipitation method. sd-LDL-c concentration was calculated by subtracting high-density lipoprotein cholesterol (HDL-c from the total cholesterol measured in the supernatant. This method was compared with the reference method (ultracentrifugation. Reference values were estimated according to the Clinical and Laboratory Standards Institute and The International Federation of Clinical Chemistry and Laboratory Medicine recommendations. sd-LDL-c concentration was measured in serums from 79 subjects with no lipid metabolism abnormalities. Results: The Passing–Bablok regression equation is y = 1.52 (0.72 to 1.73 + 0.07x (−0.1 to 0.13, demonstrating no significant statistical differences

  16. Gas Chromatographic Determination of Fatty Acids in Oils with Regard to the Assessment of Fire Hazard

    Science.gov (United States)

    Bartošová, Alica; Štefko, Tomáš

    2017-06-01

    The aim of the paper was to study and research the application of processing gas chromatographic method for the rapid and accurate determination of the composition of different types of oils, such as substances with the possibility of an adverse event spontaneous combustion or self-heating. Tendency to spontaneous combustion is chemically characterized mainly by the amount of unsaturated fatty acids, which have one or more double bonds in their molecule. Vegetable oils essentially consist of the following fatty acids: palmitic, stearic, oleic, linoleic, and linoleic. For the needs of assessment, the fire hazard must be known, in which the double bond is present, as well as their number in a molecule. As an analytical method, GCMS was used for determination of oils content. Three types of oil were used - rapeseed, sunflower, and coconut oil. Owing to the occurrence of linoleic acid C18:2 (49.8 wt.%) and oleic acid C18:1 (43.3 wt.%) with double bonds, sunflower oil is the most prone to self-heating. The coconut and rapeseed oils contain double bond FAME in lesser amount, and their propensity to self-heating is relatively low.

  17. A Large-Scale Assessment of Nucleic Acids Binding Site Prediction Programs.

    Directory of Open Access Journals (Sweden)

    Zhichao Miao

    2015-12-01

    Full Text Available Computational prediction of nucleic acid binding sites in proteins are necessary to disentangle functional mechanisms in most biological processes and to explore the binding mechanisms. Several strategies have been proposed, but the state-of-the-art approaches display a great diversity in i the definition of nucleic acid binding sites; ii the training and test datasets; iii the algorithmic methods for the prediction strategies; iv the performance measures and v the distribution and availability of the prediction programs. Here we report a large-scale assessment of 19 web servers and 3 stand-alone programs on 41 datasets including more than 5000 proteins derived from 3D structures of protein-nucleic acid complexes. Well-defined binary assessment criteria (specificity, sensitivity, precision, accuracy… are applied. We found that i the tools have been greatly improved over the years; ii some of the approaches suffer from theoretical defects and there is still room for sorting out the essential mechanisms of binding; iii RNA binding and DNA binding appear to follow similar driving forces and iv dataset bias may exist in some methods.

  18. Hydrocarbonates in atmospheric precipitation of Moscow: Monitoring data and analysis

    Science.gov (United States)

    Eremina, I. D.; Aloyan, A. E.; Arutyunyan, V. O.; Larin, I. K.; Chubarova, N. E.; Yermakov, A. N.

    2017-05-01

    Based on atmospheric precipitation monitoring data for Moscow, we have revealed a number of episodes when the content of hydrocarbonates repeatedly surpasses the equilibrium level. These facts are associated with the complex structure of precipitation, which is caused by differences in the chemical composition of condensation nuclei. As a result, the underlying surface involves two groups of drops with acidities of different nature. The acidity of the first ("metal") group is determined by the carbonate equilibrium with atmospheric CO2 and dissolved carbonates of alkaline and alkaline earth metals. The acidity of the second ("ammonium") group is characterized by the balance between ammonia absorbed from the air and atmospheric acids. Because of this, the precipitation acidity measured during the monitoring is regulated not only in the air but also in the condensate collector. The mixing of the metal and ammonium groups of precipitation is accompanied by only a partial conversion of hydrocarbonates into dissolved CO2. Its termination is hindered when CO2 actually ceases to enter the atmosphere due to mass-exchange deceleration. As a result, the content of hydrocarbonates in the collector exceeds the equilibrium level. Some estimates indicate that the acidity of the ammonia component of precipitation can be much higher than the acidity according to monitoring data. This should be taken into account in estimating the health and environmental impacts. The true level of acid rain hazard can be estimated only by measuring the acidity of individual drops, whereas the results obtained with modern tools of monitoring can underestimate this hazard.

  19. Preventing Precipitation in the ISS Urine Processor

    Science.gov (United States)

    Muirhead, Dean; Carter, Layne; Williamson, Jill; Chambers, Antja

    2017-01-01

    The ISS Urine Processor Assembly (UPA) was initially designed to achieve 85% recovery of water from pretreated urine on ISS. Pretreated urine is comprised of crew urine treated with flush water, an oxidant (chromium trioxide), and an inorganic acid (sulfuric acid) to control microbial growth and inhibit precipitation. Unfortunately, initial operation of the UPA on ISS resulted in the precipitation of calcium sulfate at 85% recovery. This occurred because the calcium concentration in the crew urine was elevated in microgravity due to bone loss. The higher calcium concentration precipitated with sulfate from the pretreatment acid, resulting in a failure of the UPA due to the accumulation of solids in the Distillation Assembly. Since this failure, the UPA has been limited to a reduced recovery of water from urine to prevent calcium sulfate from reaching the solubility limit. NASA personnel have worked to identify a solution that would allow the UPA to return to a nominal recovery rate of 85%. This effort has culminated with the development of a pretreatment based on phosphoric acid instead of sulfuric acid. By eliminating the sulfate associated with the pretreatment, the brine can be concentrated to a much higher concentration before calcium sulfate reach the solubility limit. This paper summarizes the development of this pretreatment and the testing performed to verify its implementation on ISS.

  20. On the consideration of scaling properties of extreme rainfall in Madrid (Spain) for developing a generalized intensity-duration-frequency equation and assessing probable maximum precipitation estimates

    Science.gov (United States)

    Casas-Castillo, M. Carmen; Rodríguez-Solà, Raúl; Navarro, Xavier; Russo, Beniamino; Lastra, Antonio; González, Paula; Redaño, Angel

    2018-01-01

    The fractal behavior of extreme rainfall intensities registered between 1940 and 2012 by the Retiro Observatory of Madrid (Spain) has been examined, and a simple scaling regime ranging from 25 min to 3 days of duration has been identified. Thus, an intensity-duration-frequency (IDF) master equation of the location has been constructed in terms of the simple scaling formulation. The scaling behavior of probable maximum precipitation (PMP) for durations between 5 min and 24 h has also been verified. For the statistical estimation of the PMP, an envelope curve of the frequency factor ( k m ) based on a total of 10,194 station-years of annual maximum rainfall from 258 stations in Spain has been developed. This curve could be useful to estimate suitable values of PMP at any point of the Iberian Peninsula from basic statistical parameters (mean and standard deviation) of its rainfall series. [Figure not available: see fulltext.

  1. Assessing the applicability of TMPA-3B42V7 precipitation dataset in wavelet-support vector machine approach for suspended sediment load prediction

    Science.gov (United States)

    Himanshu, Sushil Kumar; Pandey, Ashish; Yadav, Basant

    2017-07-01

    In the present study, the latest Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) research product 3B42V7 has been evaluated over gauge-based India Meteorological Department (IMD) gridded dataset employing statistical and contingency table methods for two South Indian watersheds. A comparative analysis of TMPA-3B42V7 with IMD gauge-based gridded dataset was carried out on daily, monthly, seasonal and yearly basis for 16 years (1998-2013). The study revealed that TMPA estimates performed reasonably well with the gauge-based gridded dataset, however, some significant biases were also observed. It has been observed that TMPA overestimates at very light rain, but underestimates at light, moderate, heavy and very heavy rainfall intensities. Further, the TMPA estimates was evaluated for prediction of daily suspended sediment load (SL) employing Support Vector Machine (SVM) with wavelet analysis (WASVM). Initially, 1-day ahead SL prediction was performed using best WASVM model. The results showed that 1-day predictions were very precise and shows a better agreement with the observed SL data. Later, the developed WASVM model was used for the prediction of SL for the higher leads period. The statistical analysis shows that the developed WASVM model could predict the target value successfully up to 6-days lead and found to be not suitable for higher lead specifically in the selected watersheds with similar hydro-climatic conditions like the ones selected in this study. Predictions results of WASVM model is superior to conventional SVM model and could be used as an effective forecasting tool for hydrological applications. The study suggest that the use of TMPA precipitation estimates can be a compensating approach after suitable bias correction and have potential for SL prediction in data-sparse regions.

  2. Aboveground carbon in Quebec forests: stock quantification at the provincial scale and assessment of temperature, precipitation and edaphic properties effects on the potential stand-level stocking

    Directory of Open Access Journals (Sweden)

    Louis Duchesne

    2016-03-01

    Full Text Available Biological carbon sequestration by forest ecosystems plays an important role in the net balance of greenhouse gases, acting as a carbon sink for anthropogenic CO2 emissions. Nevertheless, relatively little is known about the abiotic environmental factors (including climate that control carbon storage in temperate and boreal forests and consequently, about their potential response to climate changes. From a set of more than 94,000 forest inventory plots and a large set of spatial data on forest attributes interpreted from aerial photographs, we constructed a fine-resolution map (∼375 m of the current carbon stock in aboveground live biomass in the 435,000 km2 of managed forests in Quebec, Canada. Our analysis resulted in an area-weighted average aboveground carbon stock for productive forestland of 37.6 Mg ha−1, which is lower than commonly reported values for similar environment. Models capable of predicting the influence of mean annual temperature, annual precipitation, and soil physical environment on maximum stand-level aboveground carbon stock (MSAC were developed. These models were then used to project the future MSAC in response to climate change. Our results indicate that the MSAC was significantly related to both mean annual temperature and precipitation, or to the interaction of these variables, and suggest that Quebec’s managed forests MSAC may increase by 20% by 2041–2070 in response to climate change. Along with changes in climate, the natural disturbance regime and forest management practices will nevertheless largely drive future carbon stock at the landscape scale. Overall, our results allow accurate accounting of carbon stock in aboveground live tree biomass of Quebec’s forests, and provide a better understanding of possible feedbacks between climate change and carbon storage in temperate and boreal forests.

  3. Assessment of acid neutralizing capacity in cola-based drinks and energy beverages by artificial saliva.

    Science.gov (United States)

    Felix, Kariny Ramos; Bressan, Maria Claudia; Kanis, Luiz Alberto; de Oliveira, Marcelo Tomas

    2013-07-01

    To assess the pH of regular and light cola-based drinks and energy drinks, and examine the acid neutralizing capacity by the addition of artificial saliva. Ten packages of each product purchased locally at different stores were evaluated. The pH was measured by a pH-electrode calibrated in standard buffer solutions. To assess the pH neutralizing capacity, 1 ml/min of artificial saliva was added until a pH of 5.5 set as a cutoff point was reached in the tested solution. The data were subjected to analysis of variance (ANOVA), at the 0.05 significance level. The surveyed beverages had an initial acidic pH, ranging between 2.3 and 3.4. The average amount of saliva required to raise the pH of the cola-based drinks above 5.5 ranged between 6.0 and 6.8 ml. Energy drinks used volumes between 11.3 and 12.5 ml; however, it was not possible to achieve a pH of 5.5. According to the methodology used, it was concluded that: (1) All beverages analyzed showed an initial acidic pH. (2) There was no statistical difference between the initial pH level and acid neutralization by the addition of artificial saliva in both regular and light drinks. It was not possible to reach the appropriate pH, set as the cutoff point, for the energy drinks.

  4. Opportunity integrated assessment facilitating critical thinking and science process skills measurement on acid base matter

    Science.gov (United States)

    Sari, Anggi Ristiyana Puspita; Suyanta, LFX, Endang Widjajanti; Rohaeti, Eli

    2017-05-01

    Recognizing the importance of the development of critical thinking and science process skills, the instrument should give attention to the characteristics of chemistry. Therefore, constructing an accurate instrument for measuring those skills is important. However, the integrated instrument assessment is limited in number. The purpose of this study is to validate an integrated assessment instrument for measuring students' critical thinking and science process skills on acid base matter. The development model of the test instrument adapted McIntire model. The sample consisted of 392 second grade high school students in the academic year of 2015/2016 in Yogyakarta. Exploratory Factor Analysis (EFA) was conducted to explore construct validity, whereas content validity was substantiated by Aiken's formula. The result shows that the KMO test is 0.714 which indicates sufficient items for each factor and the Bartlett test is significant (a significance value of less than 0.05). Furthermore, content validity coefficient which is based on 8 experts is obtained at 0.85. The findings support the integrated assessment instrument to measure critical thinking and science process skills on acid base matter.

  5. The Frontier Between Adsorption and Precipitation of Polyacrylic Acid on Calcium Carbonate Frontière entre adsorption et précipitation de l'acide polyacrylique sur le carbonate de calcium

    Directory of Open Access Journals (Sweden)

    Cabane B.

    2006-12-01

    Full Text Available Adsorption of polymers on mineral surfaces allowing colloidal stability have widespread applications in industrial processes. The binding mechanism has been quite well described on oxide surfaces. Mainly in terms of hydrogen bonds and electrostatic interactions between charged sites and polymer segments. This phenomenon has been modelized and the influence of pH. Ionic strentgh, and molecular weight can be calculated or predicted. In the case of sparingly soluble substrates such as BaSO4, CaCO3 or CaSO4, several problems arise : the difficulty for the identification of surface sites and the interference of ions coming from the material's solubility. In the case of calcite, the solubility imposes dissolved calcium ions in solution which could complex the polyelectrolyte and reduce its solubility. For that purpose, we have measured the binding energy using microcalorimetry. Microcalorimetric measurements have shown that the adsorption enthalpy is weakly enclothermic: about + 2 kj/mol. Interestingly, this value is very closed to that of calcium complexation with PANa. It is suggested that the driving force for adsorption is the net gain in entropy of the system. The microcalorimetric adsorption isotherm does not show any evidence for a strongly exothermic interaction between positive edges and negative segment of the polyion. Practically, in most cases, adsorption of polymers is calculated from the decrease of its concentration in the solution after separation of the solid by centrifugation. This procedure does not discriminate therefore between real adsorption and phase separation. To answer the question, we have performed adsorption experiments using a dialysis membrane to separate the solid particles from the solution. It has been established that in some circumstances, depending on the relative amount of calcite, calcium ions and polyelectrolyte, precipitation takes place rather than adsorption. This is especially the case at low polymer

  6. Solute mixing regulates heterogeneity of mineral precipitation in porous media: Effect of Solute Mixing on Precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Cil, Mehmet B.; Xie, Minwei; Packman, Aaron I.; Buscarnera, Giuseppe (NWU); (HKUST-- China)

    2017-07-04

    Synchrotron X-ray microtomography was used to track the spatiotemporal evolution of mineral precipitation and the consequent alteration of the pore structure. Column experiments were conducted by injecting CaCl2 and NaHCO3 solutions into granular porous media either as a premixed supersaturated solution (external mixing) or as separate solutions that mixed within the specimen (internal mixing). The two mixing modes produced distinct mineral growth patterns. While internal mixing promoted transverse heterogeneity with precipitation at the mixing zone, external mixing favored relatively homogeneous precipitation along the flow direction. The impact of precipitation on pore water flow and permeability was assessed via 3-D flow simulations, which indicated anisotropic permeability evolution for both mixing modes. Under both mixing modes, precipitation decreased the median pore size and increased the skewness of the pore size distribution. Such similar pore-scale evolution patterns suggest that the clogging of individual pores depends primarily on local supersaturation state and pore geometry.

  7. Trajectory analysis of acid deposition data from the New Jersey Pine Barrens

    Energy Technology Data Exchange (ETDEWEB)

    Budd, W.W.

    1986-01-01

    Provides an example of the application of a simple method for evaluating regional interrelationships using air parcel trajectory analysis. An assessment of trajectories associated with storms affecting McDonald's Branch watershed (39 degrees 50 minutes N, 74 degrees 30 minutes W) is presented. A simple classification system is used to examine regional contributions of acid precursors. The results of the work suggest that major regional sources of acid precursor emissions dominated precipitation acidity for the Pine Barrens region from 1978 to 1981. An incremental approach to acid precipitation policy is suggested. 23 refs.

  8. Changing precipitation extremes in Europe

    Science.gov (United States)

    van den Besselaar, E. J. M.; Klein Tank, A. M. G.; van der Schrier, G.

    2010-09-01

    A growing number of studies indicate trends in precipitation extremes over Europe during recent decades. These results are generally based on descriptive indices of extremes which occur on average once (or several times) each year (or season). An example is the maximum one-day precipitation amount per year. Extreme value theory complements the descriptive indices, in order to evaluate the intensity and frequency of more rare events. Trends in more rare extremes are difficult to detect, because per definition only few events exist in the observational series. Although single extreme events cannot be simply and directly attributed to anthropogenic climate change, as there is always a finite chance that the event in question might have occurred naturally, the odds may have shifted to make some of them more likely than in an unchanging climate (IPCC, 2007). In this study we focus on climate extremes defined as rare events within the statistical reference distribution of rainfall that is monitored daily at a particular place. We examine the daily precipitation series from the European Climate Assessment and Dataset (ECA&D) project. Comparisons will be made between the trends in modest extremes detected using the descriptive indices and the trends in more rare extremes determined by fitting an extreme value distribution to the data in consecutive 20-yr periods of the record. The trends in multi-year return levels are determined for groups of stations in several subregions of Europe. Because the typical record length is about 50 yr, we will assess the trends in events that occur on average up to once in 50 yr.

  9. Environmental Life Cycle Assessment of Diets with Improved Omega-3 Fatty Acid Profiles.

    Directory of Open Access Journals (Sweden)

    Carla R V Coelho

    Full Text Available A high incidence of cardiovascular disease is observed worldwide, and dietary habits are one of the risk factors for these diseases. Omega-3 polyunsaturated fatty acids in the diet help to prevent cardiovascular disease. We used life cycle assessment to analyse the potential of two strategies to improve the nutritional and environmental characteristics of French diets: 1 modifying diets by changing the quantities and proportions of foods and 2 increasing the omega-3 contents in diets by replacing mainly animal foods with equivalent animal foods having higher omega-3 contents. We also investigated other possibilities for reducing environmental impacts. Our results showed that a diet compliant with nutritional recommendations for macronutrients had fewer environmental impacts than the current average French diet. Moving from an omnivorous to a vegetarian diet further reduced environmental impacts. Increasing the omega-3 contents in animal rations increased Eicosapentaenoic Acid (EPA and Docosahexaenoic Acid (DHA in animal food products. Providing these enriched animal foods in human diets increased their EPA and DHA contents without affecting their environmental impacts. However, in diets that did not contain fish, EPA and DHA contents were well below the levels recommended by health authorities, despite the inclusion of animal products enriched in EPA and DHA. Reducing meat consumption and avoidable waste at home are two main avenues for reducing environmental impacts of diets.

  10. Assessment of rosmarinic acid content in six Lamiaceae species extracts and their antioxidant and antimicrobial potential.

    Science.gov (United States)

    Benedec, Daniela; Hanganu, Daniela; Oniga, Ilioara; Tiperciuc, Brindusa; Olah, Neli-Kinga; Raita, Oana; Bischin, Cristina; Silaghi-Dumitrescu, Radu; Vlase, Laurian

    2015-11-01

    In the present study, six indigenous species of Lamiaceae family (Origanum vulgare L., Melissa officinalis L., Rosmarinus officinalis L., Ocimum basilicum L., Salvia officinalis L. and Hyssopus officinalis L.), have been analyzed to assess the rosmarinic acid, phenyl propane derivatives and polyphenolic contents and their antioxidant and antimicrobial potential. HPLC-MS method has been used for the analysis ofrosmarinicacid. The phenyl propane derivatives and total phenolic contents were determined using spectrophotometric method. The ethanolic extracts were screened for antioxidant activities by DPPH radical scavenging, HAPX (hemoglobin ascorbate per oxidase activity inhibition), and EPR (electron paramagnetic resonance) methods. The ethanolic extracts revealed the presence of rosmarinic acid in the largest amount in O. vulgare (12.40mg/g) and in the lowest in R. officinalis (1.33 mg/g). O. vulgare extracts exhibited the highest antioxidant capacity, in line with the rosmarinic acid and polyphenolic contents. The antimicrobial testing showed a significant activity against L. monocytogenes, S. aureus and C. albicans for all six extracts.

  11. The Global Precipitation Mission

    Science.gov (United States)

    Braun, Scott; Kummerow, Christian

    2000-01-01

    The Global Precipitation Mission (GPM), expected to begin around 2006, is a follow-up to the Tropical Rainfall Measuring Mission (TRMM). Unlike TRMM, which primarily samples the tropics, GPM will sample both the tropics and mid-latitudes. The primary, or core, satellite will be a single, enhanced TRMM satellite that can quantify the 3-D spatial distributions of precipitation and its associated latent heat release. The core satellite will be complemented by a constellation of very small and inexpensive drones with passive microwave instruments that will sample the rainfall with sufficient frequency to be not only of climate interest, but also have local, short-term impacts by providing global rainfall coverage at approx. 3 h intervals. The data is expected to have substantial impact upon quantitative precipitation estimation/forecasting and data assimilation into global and mesoscale numerical models. Based upon previous studies of rainfall data assimilation, GPM is expected to lead to significant improvements in forecasts of extratropical and tropical cyclones. For example, GPM rainfall data can provide improved initialization of frontal systems over the Pacific and Atlantic Oceans. The purpose of this talk is to provide information about GPM to the USWRP (U.S. Weather Research Program) community and to discuss impacts on quantitative precipitation estimation/forecasting and data assimilation.

  12. Precipitation Reconstruction (PREC)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The PREC data set is an analysis of monthly precipitation constructed on a 2.5(o)lat/lon grid over the global for the period from 1948 to the present. The land...

  13. The effect of the 2014 Holuhraun eruption (Bárdarbunga, Iceland) on precipitation chemistry and associated environmental impact

    Science.gov (United States)

    Stefánsdóttir, Gerður; Keller, Nicole S.; Björk Jónasdottir, Elín; Sigurðsson, Árni; Björk Þorláksdóttir, Svava; Pfeffer, Melissa Anne; Stefánsson, Andri; von Löwis, Sibylle; Reynir Gíslason, Sigurður; Barsotti, Sara

    2015-04-01

    The Holuhraun eruption that started at the end of August 2014 in Central Iceland has resulted in large quantities of gases emitted to the atmosphere, where the preliminary SO2 emission rates have been estimated to be ~400 kg/s with some days greater than 1000 kg/s in the beginning of the eruption. The major gases include H2O, SO2, CO2, HCl and HF. Sulfur dioxide in the atmosphere hydrates and oxidizes to form sulfuric acid (H2SO4) which, together with the other acid gases HCl and HF, results in acid rain. As part of the ongoing monitoring effort, precipitation samples have been collected regularly since shortly after the start of the eruption to assess whether the volcanic gas emission is causing significant changes in precipitation chemistry. Samples (rain and snow) from 21 locations around Iceland were analyzed for the acid gases, including the determination of pH, SO4, Cl and F concentrations. Unpolluted precipitation in Iceland has an average pH value of 5.77. The pH values of precipitation since the start of the eruption range from 3.18 to 7.48. Considerable SO4, Cl and F chemical loads have also been observed. Based on the comparison of the chemical composition of precipitation before and after the onset of the eruption, about 40% of precipitation samples show characteristics of volcanic gas input, with ~5% showing major effects. Gas polluted precipitation, especially when having low pH and high HF load, can have severe environmental effects, notably on the chemical composition of groundwater, water ponds, lakes and rivers. It can influence human health conditions and affect ecosystems e.g. vegetation and aquatic life. These effects can be especially severe in a long term eruption and with a high emission rate as is the case for the Holuhraun eruption. To assess the environmental impact of the chemical composition of gas-polluted precipitation, the chemical data have been integrated with meteorological data in order to estimate the locations of potential

  14. Modeling Dissolution and Precipitation Dynamics During Dedolomitization

    Science.gov (United States)

    Edery, Y.; Scher, H.; Berkowitz, B.

    2010-12-01

    We simulate the process of dedolomitization and the precipitation of calcium carbonate using particle tracking. The study is stimulated by the results of a laboratory experiment of reactive transport of injected CaCl2/HCl in a constant flow field in a column of sucrosic dolomite particles. The injected fluid basically supplied Ca2+ and H+ and the dedolomitization is a protonation reaction yielding carbonic acid, which in a deprotonation reaction yields CO32-, and reacting with the abundant Ca2+ forms the precipitate CaCO3. The novelty of the simulation is to treat the dynamics of the rate limiting reactants with particle tracking. At each time step the local concentration of H+ determines the probability (assuming local carbonate equilibria) of precipitation and dissolution. The precipitation changes the porosity which in turn changes the local flow field. The particle tracking is governed by spatial and temporal distributions within a continuous time random walk framework. This includes the option of either advective-dispersive (Fickian) transport or the effects of disorder of heterogeneous media --- non-Fickian behavior. The dynamics of dedolomitization are examined for different flow conditions and for different spectra of velocity tails of the reactants. The fluctuations in the local velocity distributions, due to porosity changes, create conditions for positive feedbacks leading to preferential pathways and large-scale nonlinearity and precipitation banding. This feature has been observed in the laboratory experiments and is now accounted for by the simulation results at similar time frames, velocities and pH levels.

  15. Hydrolysis and rearrangement of phthalamic acid derivatives and assessment of their potential as prodrug forms for amines

    DEFF Research Database (Denmark)

    Bundgaard, H; Steffansen, B

    1990-01-01

    Although it is well-known that N-substituted phthalamic acid derivatives are readily hydrolyzed in acidic aqueous solution due to intramolecular catalysis by the neighbouring carboxy group, sparse information is available on the degradation behaviour in neutral solutions. A recent publication [5......] has claimed that N-(3-bromopropyl)phthalamic acid is very easily hydrolyzed in mildly alkaline solutions by an intramolecular catalytic effect of the ionized carboxy group. In this study, the degradation behaviour of N-(2-bromoethyl)phthalamic acid (I), N-(3-bromopropyl)phthalamic acid (II......) and various other N-alkyl and N-aryl substituted phthalamic acid derivatives were examined with the primary aim of assessing their degradation rate at physiological pH. Whereas the compounds I and II were indeed found to be easily degraded in neutral aqueous solutions, the degradation was not due...

  16. Interannual and (multi-)decadal variability in the sedimentary BIT index of Lake Challa, East Africa, over the past 2200 years: assessment of the precipitation proxy

    Science.gov (United States)

    Buckles, Laura K.; Verschuren, Dirk; Weijers, Johan W. H.; Cocquyt, Christine; Blaauw, Maarten; Sinninghe Damsté, Jaap S.

    2016-05-01

    The branched vs. isoprenoid tetraether (BIT) index is based on the relative abundance of branched tetraether lipids (brGDGTs) and the isoprenoidal GDGT crenarchaeol. In Lake Challa sediments the BIT index has been applied as a proxy for local monsoon precipitation on the assumption that the primary source of brGDGTs is soil washed in from the lake's catchment. Since then, microbial production within the water column has been identified as the primary source of brGDGTs in Lake Challa sediments, meaning that either an alternative mechanism links BIT index variation with rainfall or that the proxy's application must be reconsidered. We investigated GDGT concentrations and BIT index variation in Lake Challa sediments at a decadal resolution over the past 2200 years, in combination with GDGT time-series data from 45 monthly sediment-trap samples and a chronosequence of profundal surface sediments.Our 2200-year geochemical record reveals high-frequency variability in GDGT concentrations, and therefore in the BIT index, superimposed on distinct lower-frequency fluctuations at multi-decadal to century timescales. These changes in BIT index are correlated with changes in the concentration of crenarchaeol but not with those of the brGDGTs. A clue for understanding the indirect link between rainfall and crenarchaeol concentration (and thus thaumarchaeotal abundance) was provided by the observation that surface sediments collected in January 2010 show a distinct shift in GDGT composition relative to sediments collected in August 2007. This shift is associated with increased bulk flux of settling mineral particles with high Ti / Al ratios during March-April 2008, reflecting an event of unusually high detrital input to Lake Challa concurrent with intense precipitation at the onset of the principal rain season that year. Although brGDGT distributions in the settling material are initially unaffected, this soil-erosion event is succeeded by a massive dry-season diatom bloom in

  17. Acid-induced structural modifications of unsaturated Fatty acids and phenolic olive oil constituents by nitrite ions: a chemical assessment.

    Science.gov (United States)

    Napolitano, Alessandra; Panzella, Lucia; Savarese, Maria; Sacchi, Raffaele; Giudicianni, Italo; Paolillo, Livio; d'Ischia, Marco

    2004-10-01

    The structural modifications of the unsaturated fatty acid components of triglycerides in extra virgin olive oil (EVOO) following exposure to nitrite ions in acidic media were determined by two-dimensional (2D) NMR spectroscopy, aided by (15)N labeling and GC analysis, allowing investigation of the matrix without fractionation steps. In the presence of excess nitrite ions in a 1% sulfuric acid/oil biphasic system, extensive double bond isomerization of the oleic/linoleic acid components of triglycerides was observed associated with nitration/oxidation processes. Structurally modified species were identified as E/Z-nitroalkene, 1,2-nitrohydroxy, and 3-nitro-1-alkene(1,5-diene) derivatives based on (1)H, (13)C, and (15)N 2D NMR analysis in comparison with model compounds. Minor constituents of EVOO, including phenolic compounds and tocopherols, were also substantially modified by nitrite-derived nitrating species, even under milder reaction conditions relevant to those occurring in the gastric compartments. Novel nitrated derivatives of tyrosol, hydroxytyrosol, and oleuropein (6-8) were identified by LC/MS analysis of the polar fraction of EVOO and by comparison with synthetic samples. Overall, these results provide the first systematic description at the chemical level of the consequences of exposing EVOO to nitrite ions at acidic pH and offer an improved basis for further investigations in the field of toxic nitrosation/nitration reactions and dietary antinitrosating agents.

  18. Hourly Precipitation Data (HPD) Publication

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hourly Precipitation Data (HPD) Publication is archived and available from the National Climatic Data Center (NCDC). This publication contains hourly precipitation...

  19. Effect of calcium oxide on the efficiency of ferrous ion oxidation and total iron precipitation during ferrous ion oxidation in simulated acid mine drainage treatment with inoculation of Acidithiobacillus ferrooxidans.

    Science.gov (United States)

    Liu, Fenwu; Zhou, Jun; Jin, Tongjun; Zhang, Shasha; Liu, Lanlan

    2016-01-01

    Calcium oxide was added into ferrous ion oxidation system in the presence of Acidithiobacillus ferrooxidans at concentrations of 0-4.00 g/L. The pH, ferrous ion oxidation efficiency, total iron precipitation efficiency, and phase of the solid minerals harvested from different treatments were investigated during the ferrous ion oxidation process. In control check (CK) system, pH of the solution decreased from 2.81 to 2.25 when ferrous ions achieved complete oxidation after 72 h of Acidithiobacillus ferrooxidans incubation without the addition of calcium oxide, and total iron precipitation efficiency reached 20.2%. Efficiency of ferrous ion oxidation and total iron precipitation was significantly improved when the amount of calcium oxide added was ≤1.33 g/L, and the minerals harvested from systems were mainly a mixture of jarosite and schwertmannite. For example, the ferrous ion oxidation efficiency reached 100% at 60 h and total iron precipitation efficiency was increased to 32.1% at 72 h when 1.33 g/L of calcium oxide was added. However, ferrous ion oxidation and total iron precipitation for jarosite and schwertmannite formation were inhibited if the amount of calcium oxide added was above 2.67 g/L, and large amounts of calcium sulfate dihydrate were generated in systems.

  20. METHOD OF IMPROVING THE CARRIER PRECIPITATION OF PLUTONIUM

    Science.gov (United States)

    Kamack, H.J.; Balthis, J.H.

    1958-12-01

    Plutonium values can be recovered from acidic solutlons by adding lead nitrate, hydrogen fluoride, lantha num nitrate, and sulfurlc acid to the solution to form a carrler preclpitate. The lead sulfate formed improves the separatlon characteristics of the lanthanum fluoride carrier precipitate,

  1. Precipitation Indices Low Countries

    Science.gov (United States)

    van Engelen, A. F. V.; Ynsen, F.; Buisman, J.; van der Schrier, G.

    2009-09-01

    Since 1995, KNMI published a series of books(1), presenting an annual reconstruction of weather and climate in the Low Countries, covering the period AD 763-present, or roughly, the last millennium. The reconstructions are based on the interpretation of documentary sources predominantly and comparison with other proxies and instrumental observations. The series also comprises a number of classifications. Amongst them annual classifications for winter and summer temperature and for winter and summer dryness-wetness. The classification of temperature have been reworked into peer reviewed (2) series (AD 1000-present) of seasonal temperatures and temperature indices, the so called LCT (Low Countries Temperature) series, now incorporated in the Millennium databases. Recently we started a study to convert the dryness-wetness classifications into a series of precipitation; the so called LCP (Low Countries Precipitation) series. A brief outline is given here of the applied methodology and preliminary results. The WMO definition for meteorological drought has been followed being that a period is called wet respectively dry when the amount of precipitation is considerable more respectively less than usual (normal). To gain a more quantitative insight for four locations, geographically spread over the Low Countries area (De Bilt, Vlissingen, Maastricht and Uccle), we analysed the statistics of daily precipitation series, covering the period 1900-present. This brought us to the following definition, valid for the Low Countries: A period is considered as (very) dry respectively (very) wet if over a continuous period of at least 60 days (~two months) cq 90 days (~three months) on at least two out of the four locations 50% less resp. 50% more than the normal amount for the location (based on the 1961-1990 normal period) has been measured. This results into the following classification into five drought classes hat could be applied to non instrumental observations: Very wet period

  2. Chemical composition of precipitation and its sources in Hangzhou, China.

    Science.gov (United States)

    Xu, Hong; Bi, Xiao-Hui; Feng, Yin-Chang; Lin, Feng-Mei; Jiao, Li; Hong, Sheng-Mao; Liu, Wen-Gao; Zhang, Xiao-Yong

    2011-12-01

    To understand the origin and chemical characteristics of precipitation in Hangzhou, rainwater samples were collected from June 2006 to May 2008. All samples were analyzed for pH, electrical conductivity, and major ions (NH⁴⁺, Ca²⁺, Mg²⁺, Na⁺, K⁺, SO₄²⁻, NO₃⁻, F⁻, and Cl⁻). Acidification of precipitation in Hangzhou was serious with volume-weighted mean pH value of 4.5, while frequency of acid rain was 95%. The calculated SO₄²⁻/NO₃⁻ ratio in Hangzhou precipitation was 2.87, which indicated that the precipitation of Hangzhou belonged to sulfate-based acid rain. The results of acid neutralization analysis showed that not all the acidity in the precipitation of Hangzhou was neutralized by alkaline constituents. The results of sea salt contribution analysis showed that nearly all SO₄²⁻, Ca²⁺, and Mg²⁺ and 33.7% of K⁺ were of non-sea origins, while all Na⁺ and Cl⁻ and 66.3% of K⁺ originated from sea sources. The principal component analysis which was used to analyze the sources of various ions indicated that chemical compositions of precipitation in Hangzhou mainly came from terrestrial sources, factory emissions, fuel wood burning, and marine sources.

  3. 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

    Of the three primary sources of spatially contiguous precipitation observations (surface networks, ground-based radar, and satellite-based radar/radiometers), only the last is a viable source over ocean and much of the Earth's land. As recently as 15 years ago, users needing quantitative detail of precipitation on anything under a monthly time scale relied upon products derived from geostationary satellite thermal infrared (IR) indices. The Special Sensor Microwave Imager (SSMI) passive microwave (PMW) imagers originated in 1987 and continue today with the SSMI sounder (SSMIS) sensor. The fortunate longevity of the joint National Aeronautics and Space Administration (NASA) and Japan Aerospace Exploration Agency (JAXA) Tropical Rainfall Measuring Mission (TRMM) is providing the environmental science community a nearly unbroken data record (as of April 2012, over 14 years) of tropical and sub-tropical precipitation processes. TRMM was originally conceived in the mid-1980s as a climate mission with relatively modest goals, including monthly averaged precipitation. TRMM data were quickly exploited for model data assimilation and, beginning in 1999 with the availability of near real time data, for tropical cyclone warnings. To overcome the intermittently spaced revisit from these and other low Earth-orbiting satellites, many methods to merge PMW-based precipitation data and geostationary satellite observations have been developed, such as the TRMM Multisatellite Precipitation Product and the Climate Prediction Center (CPC) morphing method (CMORPH. The purpose of this article is not to provide a survey or assessment of these and other satellite-based precipitation datasets, which are well summarized in several recent articles. Rather, the intent is to demonstrate how the availability and continuity of satellite-based precipitation data records is transforming the ways that scientific and societal issues related to precipitation are addressed, in ways that would not be

  4. Homogenization of precipitation data in Pannonian region

    Directory of Open Access Journals (Sweden)

    Medić Nenad Đ.

    2014-01-01

    Full Text Available Testing the homogeneity of data of meteorological occurrences is very important for ensuring the reliability and accuracy of the data that will later be used in a variety of research related to the assessment and prediction of future trends of climate changes. This paper presents the verification of homogeneity of data on average annual precipitations from 19 meteorological stations in the Pannonian region. For this purpose, it has been used four different statistical tests that are applied on each meteorological station individually. It was found that 4 out of 19 meteorological stations or in 21% of the cases there are in homogeneities of precipitation data.

  5. Assessment of acid sulfate soil mapping utilizing chemical indicators in recipient waters

    Directory of Open Access Journals (Sweden)

    Beucher, A.

    2015-06-01

    Full Text Available In Finland, poor water quality and associated ecological damage in the coastal streams related to land use on acid sulfate (a.s. soils has been drawing a considerable amount of attention since the 1950’s. These soils originate from sulfide-bearing marine sediments mostly occurring in the coastal areas located below the highest shoreline of the former Litorina Sea. Of the many previous studies carried out on soil or water data, quite few gathered both and their geographic extent was relatively limited. This study aimed at assessing a.s. soil probability maps using two chemical indicators measured in the recipient waters (i.e. sulfate content and sulfate/chloride ratio for 24 catchments along the Finnish coast. All the available data was compiled for these catchments, which were surveyed using different methods (i.e. conventional mapping and two spatial modeling techniques: fuzzy logic and artificial neural networks. High sulfate contents and sulfate/ chloride ratios measured in these rivers were controlled by a.s. soils in the corresponding catchments. The extent of the most probable areas for a.s. soils in the surveyed catchments correlated with the two chemical indicators measured in the recipient waters, suggesting that the probability maps created with different methods are reliable and comparable. The use of a.s. soil related chemical indicators in water, thus, constitutes a complementary, independent and straightforward tool to assess a.s. soil probability maps.

  6. Extraneous carbon assessment in ultra-microscale radiocarbon analysis using benzene polycarboxylic acids (BPCA)

    Science.gov (United States)

    Hanke, Ulrich M.; McIntyre, Cameron P.; Schmidt, Michael W. I.; Wacker, Lukas; Eglinton, Timothy I.

    2016-04-01

    Measurements of the natural abundance of radiocarbon (14C) concentrations in inorganic and organic carbon-containing materials can be used to investigate their date of origin. Particularly, the biogeochemical cycling of specific compounds in the environment may be investigated applying molecular marker analyses. However, the isolation of specific molecules from environmental matrices requires a complex processing procedure resulting in small sample sizes that often contain less than 30 μg C. Such small samples are sensitive to extraneous carbon (Cex) that is introduced during the purification of the compounds (Shah and Pearson, 2007). We present a thorough radiocarbon blank assessment for benzene polycarboxylic acids (BPCA), a proxy for combustion products that are formed during the oxidative degradation of condensed polyaromatic structures (Wiedemeier et al, in press). The extraneous carbon assessment includes reference material for (1) chemical extraction, (2) preparative liquid chromatography (3) wet chemical oxidation which are subsequently measured with gas ion source AMS (Accelerator Mass Spectrometer, 5-100 μg C). We always use pairs of reference materials, radiocarbon depleted (14Cfossil) and modern (14Cmodern) to determine the fraction modern (F14C) of Cex.Our results include detailed information about the quantification of Cex in radiocarbon molecular marker analysis using BPCA. Error propagation calculations indicate that ultra-microscale samples (20-30 μg) are feasible with uncertainties of less than 10 %. Calculations of the constant contamination reveal important information about the source (F14C) and mass (μg) of Cex (Wacker and Christl, 2011) for each sub procedure. An external correction of compound specific radiocarbon data is essential for robust results that allow for a high degree of confidence in the 14C results. References Shah and Pearson, 2007. Ultra-microscale (5-25μg C) analysis of individual lipids by 14C AMS: Assessment and

  7. Clinical significance of precipitous labor.

    Science.gov (United States)

    Suzuki, Shunji

    2015-03-01

    Precipitous labor is defined as expulsion of the fetus within less than 3 hours of commencement of regular contractions. We retrospectively examined our cases of precipitous labor to identify the clinical significance and perinatal outcomes following precipitous labor in singleton vertex deliveries. A retrospective population-based study was conducted comparing women with singleton precipitous labor and those with labor of normal duration. We examined the clinical characteristics and outcomes by comparing patients with precipitous labor and those with labor of normal duration in 0 and two-parous singleton pregnant women. Using a multivariate analysis, precipitous labor in nulliparous women was independently associated with teenagers (adjusted OR: 1.71, 95% CI: 0.99 - 2.95, P = 0.049), preterm delivery (adjusted OR: 1.77, 95% CI: 1.16 - 2.70, P precipitous labor was associated with hypertensive disorders in singleton vertex deliveries, it was not associated with maternal or neonatal outcomes.

  8. Assessment of plasma amino acid profile in autism using cation-exchange chromatography with postcolumn derivatization by ninhydrin.

    Science.gov (United States)

    Zaki, Mona Mohamed; Abdel-Al, Hala; Al-Sawi, Mohamed

    2017-02-27

    Autism is a heterogeneous neurodevelopmental disorder. This study aimed to assess the clinical significance of amino acid profile assay in autism using cation-exchange chromatography with ninhydrin postcolumn derivatization. This study included 42 autistic children and 26 apparently healthy children. All participants were subjected to the assay of plasma amino acids (essential, nonessential, and nonstandard) using cation-exchange chromatography with postcolumn derivatization by ninhydrin. The levels of most of the essential amino acids were significantly lower in autistic children than controls. As regards nonessential amino acids, significantly lower levels for plasma cysteine, tyrosine, and serine and significantly higher levels for plasma glutamic acid were recorded in autistic children than controls. Finally, the autistic group demonstrated significantly lower levels of α-aminoadipic acid, carnosine, and β-alanine and significantly higher levels of hydroxyproline, phosphoserine, β-amino-isobutyric acid, and ammonia as compared to controls. The study revealed that autistic children exhibit distinct alterations in the plasma levels of some amino acids, which can in turn participate in the disease etiology and can be applied as a diagnostic tool for early detection of autism.

  9. The use of bioassays to assess the toxicity of sediment in an acid ...

    African Journals Online (AJOL)

    Sediment contamination may occur from various anthropogenic activities, such as mining-, agricultural- and industrial practices. Many of the contaminants arising from these activities enter the aquatic system and precipitate from the surrounding water, becoming bound to sediment particles. These bound contaminants may ...

  10. Dissolution and precipitation dynamics during dedolomitization

    Science.gov (United States)

    Edery, Yaniv; Scher, Harvey; Berkowitz, Brian

    2011-08-01

    We simulate the processes of dedolomitization and calcium carbonate precipitation using particle tracking. The study is stimulated by the results of a laboratory experiment that examined reactive transport of injected CaCl2/HCl, into a column of sucrosic dolomite particles, with a constant flow field. The injected fluid supplies Ca2+ and H+. Dedolomitization is a protonation reaction yielding carbonic acid; a subsequent deprotonation reaction yields ?, and reaction with the abundant Ca2+ forms the precipitate CaCO3. The dedolomitization and precipitation processes involve multistep, multispecies chemical reactions, with both irreversible and reversible stages. The particle tracking is governed by spatial and temporal distributions within a continuous time random walk framework. This accounts for the effects of disorder of heterogeneous media (leading to non-Fickian transport) and includes the option of treating purely advective-dispersive (Fickian) transport. The dynamics of dedolomitization are examined for different flow conditions and reaction rates. The fluctuations in the local velocity distributions, due to porosity changes, create conditions for positive feedbacks leading to development of preferential pathways, large-scale nonlinearity, and precipitation banding. These features have been observed in the laboratory experiments and are now accounted for by the simulation results at similar time frames, velocities, and pH levels.

  11. Preliminary assessment of developmental toxicity of Perfluorinated Phosphonic Acid in mice

    Science.gov (United States)

    Perfluorinated phosphonic acids (PFPAs) are a third member of the perfluoroalkyl acid (PFAA) family, and are structurally similar to the perfluoroalkyl sulfonates and perfluoroalkyl carboxylates. These emerging chemicals have recently been detected in the environment, particularl...

  12. Leucine disposal rate for assessment of amino acid metabolism in maintenance hemodialysis patients

    Science.gov (United States)

    Denny, Gerald B.; Deger, Serpil M.; Chen, Guanhua; Bian, Aihua; Sha, Feng; Booker, Cindy; Kesler, Jaclyn T.; David, Sthuthi; Ellis, Charles D.; Ikizler, T. Alp

    2016-01-01

    Background Protein energy wasting (PEW) is common in patients undergoing maintenance hemodialysis (MHD) and closely associated with poor outcomes. Insulin resistance and associated alterations in amino acid metabolism are potential pathways leading to PEW. We hypothesized that the measurement of leucine disposal during a hyperinsulinemic- euglycemic-euaminoacidemic clamp (HEAC) procedure would accurately measure the sensitivity to insulin for its actions on concomitant carbohydrate and protein metabolism in MHD patients. Methods We examined 35 MHD patients and 17 control subjects with normal kidney function by hyperinsulinemic-euglycemic clamp (HEGC) followed by HEAC clamp procedure to obtain leucine disposal rate (LDR) along with isotope tracer methodology to assess whole body protein turnover. Results The glucose disposal rate (GDR) by HEGC was 5.1 ± 2.1 mg/kg/min for the MHD patients compared to 6.3 ± 3.9 mg/kg/min for the controls (p = 0.38). The LDR during HEAC was 0.09 ± 0.03 mg/kg/min for the MHD patients compared to 0.11 ± 0.05 mg/kg/min for the controls (p = 0.009). The LDR level was correlated with whole body protein synthesis (r = 0.25; p = 0.08), with whole body protein breakdown (r = −0.38 p = 0.01) and net protein balance (r = 0.85; p < 0.001) in the overall study population. Correlations remained significant in subgroup analysis. The GDR derived by HEGC and LDR correlated well in the controls (r = 0.79, p < 0.001), but less so in the MHD patients (r = 0.58, p < 0.001). Conclusions Leucine disposal rate reliably measures amino acid utilization in MHD patients and controls in response to high dose insulin. PMID:27413537

  13. Deposition of Sulphate and Nitrogen in Alpine Precipitation of the Southern Canadian Rocky Mountains

    Science.gov (United States)

    Wasiuta, V. L.; Lafreniere, M. J.

    2011-12-01

    Atmospheric nitrogen (N) and sulphur (S) are the main contributors to acid precipitation which causes regionally persistent ecological problems. Enhanced deposition of reactive N, mainly as nitrate (NO3-) and ammonium (NH4+), also contributes to major ecological problems associated with ecosystem N saturation. Alpine ecosystems, which are generally nutrient poor and exist under extreme climatic conditions, are sensitive to environmental and climatic stressors. Studies in the USA Rocky Mountains and European Alps have shown alpine ecosystems have a particularly sensitivity to enhanced deposition of reactive N and can show ecologically destructive responses at relatively low levels of N deposition. However, evaluation of atmospheric sulphur and nitrogen deposition in mid latitude alpine Western Canada has been initiated only very recently and at only a few locations. There is little comprehension of current atmospheric flux to high altitudes or the importance of contributions from major emission sources This work quantifies the atmospheric deposition of SO42- NH4+ and NO3- to a remote alpine site in the Southern Canadian Rocky Mountains by characterizing alpine precipitation. The effect of elevation and aspect on deposition are assessed using sampling sites along elevational transects in the adjacent Haig and Robertson Valleys. Seasonal variations in deposition of SO42- NH4+ and NO3- are evaluated using the autumn, winter, and spring precipitation accumulated in the seasonal snowpack at glacial and fore glacial locations, along with collected bulk summer precipitation. Preliminary results show lower precipitation volumes, which are associated with higher SO42- and NH4+ loads, in the north west facing Robertson Valley than the south east facing Haig Glacier. However trends in deposition of SO42- NH4+ and NO3- with elevation and aspect are inconsistent over the 2008-2009 and 2009-2010 snow accumulation seasons, and 2010 bulk summer precipitation seasons that were

  14. The Global Precipitation Climatology Project (GPCP) Combined Precipitation Dataset

    Science.gov (United States)

    Huffman, George J.; Adler, Robert F.; Arkin, Philip; Chang, Alfred; Ferraro, Ralph; Gruber, Arnold; Janowiak, John; McNab, Alan; Rudolf, Bruno; Schneider, Udo

    1997-01-01

    The Global Precipitation Climatology Project (GPCP) has released the GPCP Version 1 Combined Precipitation Data Set, a global, monthly precipitation dataset covering the period July 1987 through December 1995. The primary product in the dataset is a merged analysis incorporating precipitation estimates from low-orbit-satellite microwave data, geosynchronous-orbit -satellite infrared data, and rain gauge observations. The dataset also contains the individual input fields, a combination of the microwave and infrared satellite estimates, and error estimates for each field. The data are provided on 2.5 deg x 2.5 deg latitude-longitude global grids. Preliminary analyses show general agreement with prior studies of global precipitation and extends prior studies of El Nino-Southern Oscillation precipitation patterns. At the regional scale there are systematic differences with standard climatologies.

  15. ISLSCP II Global Precipitation Climatology Centre (GPCC) Monthly Precipitation

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: The Global Precipitation Climatology Centre (GPCC), which is operated by the Deutscher Wetterdienst (National Meteorological Service of Germany), is a...

  16. ISLSCP II Global Precipitation Climatology Centre (GPCC) Monthly Precipitation

    Data.gov (United States)

    National Aeronautics and Space Administration — The Global Precipitation Climatology Centre (GPCC), which is operated by the Deutscher Wetterdienst (National Meteorological Service of Germany), is a component of...

  17. Precipitation-Based ENSO Indices

    Science.gov (United States)

    Adler, Robert; Curtis, Scott

    1998-01-01

    In this study gridded observed precipitation data sets are used to construct rainfall-based ENSO indices. The monthly El Nino and La Nina Indices (EI and LI) measure the steepest zonal gradient of precipitation anomalies between the equatorial Pacific and the Maritime Continent. This is accomplished by spatially averaging precipitation anomalies using a spatial boxcar filter, finding the maximum and minimum averages within a Pacific and Maritime Continent domain for each month, and taking differences. EI and LI can be examined separately or combined to produce one ENSO Precipitation Index (ESPI). ESPI is well correlated with traditional sea surface temperature and pressure indices, leading Nino 3.4. One advantage precipitation indices have over more conventional indices, is describing the strength and position of the Walker circulation. Examples are given of tracking the impact of ENSO events on the tropical precipitation fields.

  18. Assessment of corrosion resistance of cast cobalt- and nickel-chromium dental alloys in acidic environments.

    Science.gov (United States)

    Mercieca, Sven; Caligari Conti, Malcolm; Buhagiar, Joseph; Camilleri, Josette

    2017-10-26

    The aim of this study was to compare the degradation resistance of nickel-chromium (Ni-Cr) and cobalt-chromium (Co-Cr) alloys used as a base material for partial dentures in contact with saliva. Wiron® 99 and Wironit Extra-Hard® were selected as representative casting alloys for Ni-Cr and Co-Cr alloys, respectively. The alloys were tested in contact with deionized water, artificial saliva and acidified artificial saliva. Material characterization was performed by X-ray diffractometry (XRD) and microhardness and nanohardness testing. The corrosion properties of the materials were then analyzed using open circuit potential analysis and potentiodynamic analysis. Alloy leaching in solution was assessed by inductively coupled plasma mass spectrometry techniques. Co-Cr alloy was more stable than the Ni-Cr alloy in all solutions tested. Leaching of nickel and corrosion attack was higher in Ni-Cr alloy in artificial saliva compared with the acidified saliva. The corrosion resistance of the Co-Cr alloy was seen to be superior to that of the Ni-Cr alloy, with the former exhibiting a lower corrosion current in all test solutions. Microstructural topographical changes were observed for Ni-Cr alloy in contact with artificial saliva. The Ni-Cr alloy exhibited microstructural changes and lower corrosion resistance in artificial saliva. The acidic changes did not enhance the alloy degradation. Ni-Cr alloys are unstable in solution and leach nickel. Co-Cr alloys should be preferred for clinical use.

  19. Aqueous chlorination of mefenamic acid: kinetics, transformation by-products and ecotoxicity assessment.

    Science.gov (United States)

    Adira Wan Khalit, Wan Nor; Tay, Kheng Soo

    2016-05-18

    Mefenamic acid (Mfe) is one of the most frequently detected nonsteroidal anti-inflammatory drugs in the environment. This study investigated the kinetics and the transformation by-products of Mfe during aqueous chlorination. The potential ecotoxicity of the transformation by-products was also evaluated. In the kinetic study, the second-order rate constant (kapp) for the reaction between Mfe and free available chlorine (FAC) was determined at 25 ± 0.1 °C. The result indicated that the degradation of Mfe by FAC is highly pH-dependent. When the pH was increased from 6 to 8, it was found that the kapp for the reaction between Mfe and FAC was decreased from 16.44 to 4.4 M(-1) s(-1). Characterization of the transformation by-products formed during the chlorination of Mfe was carried out using liquid chromatography-quadrupole time-of-flight accurate mass spectrometry. Four major transformation by-products were identified. These transformation by-products were mainly formed through hydroxylation, chlorination and oxidation reactions. Ecotoxicity assessment revealed that transformation by-products, particularly monohydroxylated Mfe which is more toxic than Mfe, can be formed during aqueous chlorination.

  20. The occurrence, exposure and risk assessment of perfluoroalkyl acids in food from mainland, China.

    Science.gov (United States)

    Wang, Xinxuan; Zhang, Ruobing; Zhang, Hong; Wang, Yanping

    2017-11-01

    To study the contamination of perfluoroalkyl acids (PFAAs) in Chinese food and the risk of dietary exposure for the Chinese population, the data of 17 PFAAs covering 38 cities throughout China in 15 groups of foods were collected for meta-analysis from published and available research literature. Using food consumption and body weight parameters, estimated dietary intakes (EDIs) were calculated for evaluation using the Scenario-Based Risk Assessment (SceBRA) modelling. Among food groups, the highest ΣPFAAs concentrations and EDI contributions were both found in poultry (363 ng/g), fish and shrimp (313 ng/g), dark vegetables (309 ng/g), fruits (116 ng/g) and pork (25 ng/g). The EDI of adults in the high-exposure scenario was about twice that of the intermediate-exposure scenario, while the EDI of children was about twice that of adults' EDI in the intermediate-exposure scenario. In addition, the PFOS EDI for children under high exposure approached its tolerable daily intake (TDI). Therefore high dietary exposure to PFAAs is giving rise to an increased health risk, especially for children.

  1. Electrical operation of electrostatic precipitators

    CERN Document Server

    Parker, Ken

    2003-01-01

    The electrostatic precipitator remains on of the most cost effective means of controlling the emission of particulates from most industrial processes. This book will be of interest to both users and suppliers of electrostatic precipitators as well as advanced students on environmental based courses. The author identifies the physical and engineering basis for the development of electrical equipment for electrostatic precipitators and thoroughly explores the technological factors which optimize the efficiency of the precipitator and hence minimize emissions, as well as future developments in th

  2. Precipitation Measurement Missions Data Access

    Data.gov (United States)

    National Aeronautics and Space Administration — Tropical Rainfall Measuring Mission (TRMM) data products are currently available from 1998 to the present. Global Precipitation Measurement (GPM) mission data...

  3. Measuring precipitation with a geolysimeter

    Science.gov (United States)

    Smith, Craig D.; van der Kamp, Garth; Arnold, Lauren; Schmidt, Randy

    2017-10-01

    Using the relationship between measured groundwater pressures in deep observation wells and total surface loading, a geological weighing lysimeter (geolysimeter) has the capability of measuring precipitation event totals independently of conventional precipitation gauge observations. Correlations between groundwater pressure change and event precipitation were observed at a co-located site near Duck Lake, SK, over a multi-year and multi-season period. Correlation coefficients (r2) varied from 0.99 for rainfall to 0.94 for snowfall. The geolysimeter was shown to underestimate rainfall by 7 % while overestimating snowfall by 9 % as compared to the unadjusted gauge precipitation. It is speculated that the underestimation of rainfall is due to unmeasured run-off and evapotranspiration within the response area of the geolysimeter during larger rainfall events, while the overestimation of snow is at least partially due to the systematic undercatch common to most precipitation gauges due to wind. Using recently developed transfer functions from the World Meteorological Organization's (WMO) Solid Precipitation Intercomparison Experiment (SPICE), bias adjustments were applied to the Alter-shielded, Geonor T-200B precipitation gauge measurements of snowfall to mitigate wind-induced errors. The bias between the gauge and geolysimeter measurements was reduced to 3 %. This suggests that the geolysimeter is capable of accurately measuring solid precipitation and can be used as an independent and representative reference of true precipitation.

  4. Measuring precipitation with a geolysimeter

    Directory of Open Access Journals (Sweden)

    C. D. Smith

    2017-10-01

    Full Text Available Using the relationship between measured groundwater pressures in deep observation wells and total surface loading, a geological weighing lysimeter (geolysimeter has the capability of measuring precipitation event totals independently of conventional precipitation gauge observations. Correlations between groundwater pressure change and event precipitation were observed at a co-located site near Duck Lake, SK, over a multi-year and multi-season period. Correlation coefficients (r2 varied from 0.99 for rainfall to 0.94 for snowfall. The geolysimeter was shown to underestimate rainfall by 7 % while overestimating snowfall by 9 % as compared to the unadjusted gauge precipitation. It is speculated that the underestimation of rainfall is due to unmeasured run-off and evapotranspiration within the response area of the geolysimeter during larger rainfall events, while the overestimation of snow is at least partially due to the systematic undercatch common to most precipitation gauges due to wind. Using recently developed transfer functions from the World Meteorological Organization's (WMO Solid Precipitation Intercomparison Experiment (SPICE, bias adjustments were applied to the Alter-shielded, Geonor T-200B precipitation gauge measurements of snowfall to mitigate wind-induced errors. The bias between the gauge and geolysimeter measurements was reduced to 3 %. This suggests that the geolysimeter is capable of accurately measuring solid precipitation and can be used as an independent and representative reference of true precipitation.

  5. Precipitation controls on nutrient budgets in subtropical and tropical forests and the implications under changing climate

    Science.gov (United States)

    Chang, Chung-Te; Wang, Lih-Jih; Huang, Chuan, Jr.; Liu, Chiung-Pin; Wang, Chiao-Ping; Lin, Neng-Huei; Wang, Lixin; Lin, Teng-Chiu

    2017-05-01

    Biological, geological and hydrological drivers collectively control forest biogeochemical cycling. However, based on a close examination of recent literature, we argue that the role of hydrological control particularly precipitation on nutrient budgets is significantly underestimated in subtropical and tropical forests, hindering our predictions of future forest nutrient status under a changing climate in these systems. To test this hypothesis, we analyzed two decades of monthly nutrient input and output data in precipitation and streamwater from a subtropical forested watershed in Taiwan, one of the few sites that has long-term nutrient input-output data in the tropics and subtropics. The results showed that monthly input and output of all ions and budgets (output - input) of most ions were positively correlated with precipitation quantity and there was a surprisingly greater net ion export during the wet growing season, indicating strong precipitation control on the nutrient budget. The strong precipitation control is also supported by the divergence of acidic precipitation and near neutral acidity of streamwater, with the former being independent from precipitation quantity but the latter being positively related to precipitation quantity. An additional synthesis of annual precipitation quantity and nutrient budgets of 32 forests across the globe showed a strong correlation between precipitation quantity and nutrient output-input budget, indicating that strong precipitation control is ubiquitous at the global scale and is particularly important in the humid tropical and subtropical forests. Our results imply that climate change could directly affect ecosystem nutrient cycling in the tropics through changes in precipitation pattern and amount.

  6. Inducing mineral precipitation in groundwater by addition of phosphate

    Directory of Open Access Journals (Sweden)

    Hartmann Thomas

    2011-10-01

    Full Text Available Abstract Background Induced precipitation of phosphate minerals to scavenge trace elements from groundwater is a potential remediation approach for contaminated aquifers. The success of engineered precipitation schemes depends on the particular phases generated, their rates of formation, and their long term stability. The purpose of this study was to examine the precipitation of calcium phosphate minerals under conditions representative of a natural groundwater. Because microorganisms are present in groundwater, and because some proposed schemes for phosphate mineral precipitation rely on stimulation of native microbial populations, we also tested the effect of bacterial cells (initial densities of 105 and 107 mL-1 added to the precipitation medium. In addition, we tested the effect of a trace mixture of propionic, isovaleric, formic and butyric acids (total concentration 0.035 mM. Results The general progression of mineral precipitation was similar under all of the study conditions, with initial formation of amorphous calcium phosphate, and transformation to poorly crystalline hydroxylapatite (HAP within one week. The presence of the bacterial cells appeared to delay precipitation, although by the end of the experiments the overall extent of precipitation was similar for all treatments. The stoichiometry of the final precipitates as well as Rietveld structure refinement using x-ray diffraction data indicated that the presence of organic acids and bacterial cells resulted in an increasing a and decreasing c lattice parameter, with the higher concentration of cells resulting in the greatest distortion. Uptake of Sr into the solids was decreased in the treatments with cells and organic acids, compared to the control. Conclusions Our results suggest that the minerals formed initially during an engineered precipitation application for trace element sequestration may not be the ones that control long-term immobilization of the contaminants. In

  7. Characterization and reactivity assessment of organic substrates for sulphate-reducing bacteria in acid mine drainage treatment.

    Science.gov (United States)

    Zagury, Gerald J; Kulnieks, Viktors I; Neculita, Carmen M

    2006-08-01

    Acid mine drainage (AMD), which contains high concentrations of sulphate and dissolved metals, is a serious environmental problem. It can be treated in situ by sulphate reducing bacteria (SRB), but effectiveness of the treatment process depends on the organic substrate chosen to supply the bacteria's carbon source. Six natural organic materials were characterized in order to investigate how well these promote sulphate reduction and metal precipitation by SRB. Maple wood chips, sphagnum peat moss, leaf compost, conifer compost, poultry manure and conifer sawdust were investigated in terms of their carbon (TOC, TIC, DOC) and nitrogen (TKN) content, as well as their easily available substances content (EAS). Single substrates, ethanol, a mixture of leaf compost (30% w/w), poultry manure (18% w/w), and maple wood chips (2% w/w), and the same mixture spiked with formaldehyde were then tested in a 70-day batch experiment to evaluate their performance in sulphate reduction and metal removal from synthetic AMD. Metal removal efficiency in batch reactors was as high as 100% for Fe, 99% for Mn, 99% for Cd, 99% for Ni, and 94% for Zn depending on reactive mixtures. Early metal removal (0-12d) was attributed to the precipitation of (oxy)hydroxides and carbonate minerals. The lowest metal and sulphate removal efficiency was found in the reactor containing poultry manure as the single carbon source despite its high DOC and EAS content. The mixture of organic materials was most effective in promoting sulphate reduction, followed by ethanol and maple wood chips, and single natural organic substrates generally showed low reactivity. Formaldehyde (0.015% (w/v)) provided only temporary bacterial inhibition. Although characterization of substrates on an individual basis provided insight on their chemical make-up, it did not give a clear indication of their ability to promote sulphate reduction and metal removal.

  8. Assessment of the importance of acidic fogwater and cloudwater in affecting terrestrial vegetation: Some important case studies

    Energy Technology Data Exchange (ETDEWEB)

    Irving, P.M.; Eagar, C. (National Acid Precipitation Assessment Program, Washington, DC (USA). Office of the Director of Research; Forest Service, Broomall, PA (USA). Northeastern Forest Experiment Station)

    1989-01-01

    The purpose of this paper is to present some examples of terrestrial effects of concern as case studies to demonstrate the methodology to be used for answering questions of the NAPAP Integrated Assessment. The two examples presented, one each for forestry and crops, represent what is probably the worst case'' for possible acidic rain effects on crops and forests. Both examples revolve around hypotheses centering on stress from acidic fogwater or cloudwater. Because it is likely that additional information will become available prior to the publication of the Integrated Assessment, it should be understood that the analyses and interpretations presented on the following pages are subject to change when NAPAP publishes its final Assessment in 1990. 76 refs., 3 tabs.

  9. Hydroxy, carboxylic and amino acid functionalized ...

    Indian Academy of Sciences (India)

    precipitation method and modified with different coating agents such as ascorbic acid, hexanoic acid, salicylic acid, L-arginine and L-cysteine. The synthesized nanoparticles were characterized by various techniques such as FT IR, XRD, VSM, ...

  10. Docosahexaenoic acid liposomes for targeting chronic inflammatory diseases and cancer : An in vitro assessment

    NARCIS (Netherlands)

    Alaarg, Amr; Jordan, Nan Yeun; Verhoef, Johan J F; Metselaar, Josbert M.; Storm, G; Kok, Robbert J.

    2016-01-01

    Inflammation, oxidative stress, and uncontrolled cell proliferation are common key features of chronic inflammatory diseases, such as atherosclerosis and cancer. ω3 polyunsaturated fatty acids (PUFAs; also known as omega3 fatty acids or fish oil) have beneficial effects against inflammation upon

  11. Resistivity Problems in Electrostatic Precipitation

    Science.gov (United States)

    White, Harry J.

    1974-01-01

    The process of electrostatic precipitation has ever-increasing application in more efficient collection of fine particles from industrial air emissions. This article details a large number of new developments in the field. The emphasis is on high resistivity particles which are a common cause of poor precipitator performance. (LS)

  12. Precipitation in the Solar System

    Science.gov (United States)

    McIntosh, Gordon

    2007-01-01

    As an astronomy instructor, I am always looking for commonly observed Earthly experiences to help my students and me understand and appreciate similar occurrences elsewhere in the solar system. Recently I wrote a short TPT article on frost. This paper is on the related phenomena of precipitation. Precipitation, so common on most of the Earth's…

  13. Polylactic acid trays for fresh-food packaging: A Carbon Footprint assessment.

    Science.gov (United States)

    Ingrao, Carlo; Tricase, Caterina; Cholewa-Wójcik, Agnieszka; Kawecka, Agnieszka; Rana, Roberto; Siracusa, Valentina

    2015-12-15

    This paper discusses application of Carbon Footprint (CF) for quantification of the 100-year Global Warming Potential (GWP100) associated with the life cycle of polylactic acid (PLA) trays for packaging of fresh foods. A comparison with polystyrene (PS)-based trays was done considering two different transport system scenarios for PLA-granule supply to the tray production firm: a transoceanic freight vessel and an intercontinental freight aircraft. Doing so enabled estimation of the influence of the transportation phase on the GHG-emission rate associated with the PLA-trays' life cycle. From the assessment, the GWP100 resulted to be mainly due to PLA-granulate production and to its transportation to the tray manufacturing facility. Also, the study documented that, depending upon the transport system considered, the CF associated with the life cycle of the PLA trays can worsen so much that the latter are no longer GHG-emission saving as they are expected to be compared to the PS ones. Therefore, based upon the findings of the study, it was possible for the authors to understand the importance and the need of accounting for the transport-related issues in the design of PLA-based products, thus preserving their environmental soundness compared to traditional petroleum-based products. In this context, the study could be used as the base to reconsider the merits of PLA usage for product manufacturing, especially when high distances are implied, as in this analysed case. So, the authors believe that new research and policy frameworks should be designed and implemented for both development and promotion of more globally sustainable options. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Assessment of semi-automated nucleic acid testing programme in a Regional Blood Transfusion Centre.

    Science.gov (United States)

    Ghosh, Kanjaksha; Mishra, Kanchan Kumar; Trivedi, Apeksha; Sosa, Sheetal; Patel, Krima

    2017-01-01

    Detection of human immunodeficiency virus type-1 (HIV-1), hepatitis-C (HCV) and hepatitis-B virus (HBV) in the blood donors is crucial. An efficient form of detection is nucleic acid testing (NAT) in blood screening. We assessed the suitability of commercial NAT testing in a developing country, focusing on the Altona RealStar assay and the method of Sacace Biotechnologies. We have standardised and validated commercially available NAT kits with a semi-automated system for detection of HBV, HCV and HIV-1 in blood donations. The MP-NAT (mini-pool) assay consists of pooling of sample, virus extraction, amplification and detection with commercially available NAT kits. An internal control (IC) is incorporated in the assay to monitor the extraction, target amplification and detection process. The sensitivity of the Altona RealStar assay at 10-MP for each viral target was evaluated, HBV showed amplification in all diluted positive samples of 100, 50, 25, 10 and 5 IU/ml. HIV and HCV infected samples showed amplification in all diluted positive samples of 500, 100, 50 and 30 IU/ml. For HIV, out of six diluted samples of 30 IU/ml, five were amplified. A total of 14,170 seronegative blood samples were tested by RealStar PCR kit in 10-MP and 6 (0.042%) samples/pools were positive. A total of 65,362 seronegative blood donations were also tested by kits of Sacace Biotechnologies, in 10-MP and 45 (0.075%) pools were positive. The prevalence of combined NAT yield cases among routine donors was 1 in 1559 donations tested for all the 3 viruses. The semi-automated combined system for NAT screening assays is robust, sensitive, reproducible, and this gives an additional layer of safety with affordable cost.

  15. Myocardial damage assessed by indium-111-antimyosin: correlation with persistent enteroviral ribonucleic acid in dilated cardiomyopathy

    Energy Technology Data Exchange (ETDEWEB)

    Bengel, F.M. [Department of Nuclear Medicine, University of Erlangen (Germany)]|[Department of Nuclear Medicine, Technical University of Munich (Germany); Feistel, H.; Wolf, F. [Department of Nuclear Medicine, University of Erlangen (Germany); Moshage, W.; Bachmann, K. [Department of Cardiology, University of Erlangen (Germany)

    1997-09-01

    The persistence of enteroviral ribonucleic acid (RNA) in the myocardium has been implicated as a pathogenetic factor in idiopathic dilated cardiomyopathy. Enteroviral persistence may lead to myocardial cell membrane damage, resulting in increased uptake of antimyosin antibodies. To further evaluate this hypothesis, a direct comparison of myocardial antimyosin uptake with the presence of enteroviral RNA was performed in ten patients (one female, nine male; 53{+-}8 years) with chronic dilated cardiomyopathy. Planar antimyosin images were obtained 48 h after the injection of indium-111-labelled antimyosin Fab. Using a region of interest technique, the heart to lung uptake ratio (HLR) was calculated as a semiquantitative parameter of myocardial tracer uptake. Cardiac catheterization was performed to assess left ventricular function and to obtain myocardial biopsy samples. In the biopsy samples, gene amplification by polymerase chain reaction (PCR) was used to specifically detect enteroviral RNA. In the ten patients, the left ventricular ejection fraction was 39%{+-}11% and the end-diastolic volume 131{+-}46 ml/m{sup 2}. The HLR was 1.72{+-}0.21 and showed no correlation with functional parameters. In two patients with a positive PCR consistent with persisting enteroviral RNA, the HLR was not higher than that in eight patients with a negative PCR (1.46{+-}0.18 vs 1.78{+-}0.18, respectively). These results suggest that increased uptake of {sup 111}In-antimyosin in chronic idiopathic dilated cardiomyopathy cannot be explained by pure persistence of enteroviral RNA. Other pathogenetic factors such as myocardial autoantibodies or microvascular spasm may be responsible for myocyte membrane damage detected by antimyosin. (orig.). With 3 figs., 1 tab.

  16. Assessing leaf spectral properties of Phragmites australis impacted by acid mine drainage

    Directory of Open Access Journals (Sweden)

    Heidi van Deventer

    2014-07-01

    Full Text Available The decanting of acid mine drainage (AMD from the Western Basin on the Witwatersrand in late 2010 raised concerns about AMD risks in other gold, coal and copper mining areas of South Africa. Field spectroscopy and the use of vegetation indices could offer an affordable and easy means of monitoring the impact of mine water and/or AMD on vegetation. The impact of raw and treated mine water or contaminated soil on wetland vegetation often manifests in growth inhibition and reduction of foliar pigments and nutrient levels. Surveying the impact on wetland vegetation or underlying soils can be difficult and expensive considering the cost of laboratory analysis of samples. The potential of field spectroscopy for detecting the impact of mine water on wetland vegetation was examined by assessing (1 whether there was a significant difference in leaf spectra between sites receiving mine water and a non-impacted control site and (2 whether there was a gradation of vegetation condition downstream from the decanting site. Two vegetation indices were derived from portable field spectrometer-measured spectra of five green leaves of Phragmites australis – the chlorophyll red edge position (REP and the normalised difference vegetation index (NDVI – for two dormant (winter and peak growth (summer seasons in 2011–2012. Mean REP and NDVI values were significantly (p"less than"0.05 lower for affected sites compared to the control site for both seasons and years. The range of REP values for young green leaves in winter for affected sites was 695–720 nm compared to the narrower range of 705–721 nm for the control site. The mean REP values for young green leaves in winter was 708 nm for the affected sites compared to 716 nm for the control site. The downstream gradation, however, fluctuated for REP and NDVI over the study period. We conclude that field spectroscopy shows potential to serve as a relatively quick and affordable means to assess the condition and

  17. Modeling solid-state precipitation

    CERN Document Server

    Nebylov, AlexanderKozeschnik, Ernst

    2012-01-01

    Over recent decades, modeling and simulation of solid-state precipitation has attracted increased attention in academia and industry due to their important contributions in designing properties of advanced structural materials and in increasing productivity and decreasing costs for expensive alloying. In particular, precipitation of second phases is an important means for controlling the mechanical-technological properties of structural materials. However, profound physical modeling of precipitation is not a trivial task. This book introduces you to the classical methods of precipitation modeling and to recently-developed advanced, computationally-efficient techniques. If you're a research professional, academic, or student, you'll learn: nucleation theory, precipitate growth, calculation of interfacial energies. advanced techniques for technologically relevant multicomponent systems and complex thermo-mechanical treatments. numerical approaches using evolution equations and discrete particle size distribu...

  18. Extraction and precipitation of phosphorus from sewage sludge.

    Science.gov (United States)

    Shiba, Nothando Cynthia; Ntuli, Freeman

    2017-02-01

    Raw sewage sludge from East Rand Water Care Association (ERWAT) had high phosphorus (P) content, approximately 15.2% (w/w) P 2 O 5 , which indicates a potential resource for the limiting nutrient. Leaching sewage sludge with 1M sulphuric acid at 5% solid loading for 2h resulted in an 82% phosphorus extraction. However, the phosphorus was recovered as iron phosphates, thus a further purification step using ion exchange to remove iron was required to increase the degree of P release. Magnesium oxide and ammonium hydroxide were used as magnesium and nitrogen sources, respectively, as well as pH regulators to precipitate P as struvite. 57% struvite was precipitated and the total phosphorus content of the precipitate was 25.9%. Kinetic studies showed that the leaching of phosphorus follows the Dickinson model for the first 100min with a rate of reaction of about 2×10 -5 s -1 . The rate limiting step is controlled by diffusion. Phosphorus solubility in 2% critic acid was almost 96%, which is the amount of phosphorus available to plants if the precipitate is applied as a fertiliser. Environmental, gram-positive Bacillus subtilis were found in the precipitate, which are harmless to the environment since they already exist in the soil where the precipitate can be applied as a fertiliser. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Assessment of different folic acid supplementation doses for low-birth-weight infants.

    Science.gov (United States)

    Çelik, Fatma Çakmak; Aygün, Canan; Gülten, Sedat; Bedir, Abdulkerim; Çetinoğlu, Erhan; Küçüködük, Şükrü; Bek, Yüksel

    2016-12-01

    The adequacy of 50 mcg folic acid supplementation given to low-birth-weight babies was investigated. The folate levels of the mothers and infants, and breastmilk, and the optimum dose for folic acid supplementation were also investigated. After obtaining blood from 141 low-birth-weight infants on the 1st day of life for serum and red cell folate levels, the infants were randomly allocated into three groups according to the folic acid supplement dose. Forty-six infants were given 25 μg/d folic acid, 39 were given 50 μg/d folic acid, and 44 were given 75 μg/d folic acid. Folic acid could not be given to 12 infants. Follow-up blood samples were obtained at the end of folic acid supplementation. Maternal samples for red cell and serum folate levels and breast milk folate levels were obtained within the first 48 hours and the samples for measuring breastmilk folate level were obtained on the 3rd day postnatally. The feeding modes of the infants, maternal folic acid intake, and details of neonate intensive care unit course were recorded. The mean birth weight and gestational age of the infants were found as 1788.2±478.4 g and 33.5±2.9 weeks, respectively. The mean serum and red cell folate levels on admission were found as 21.2±12.2 ng/mL and 922.7±460.7 ng/mL, respectively. The mean maternal serum and red cell folate levels and the mean breast milk folate levels were found as 12.3±7.5 ng/mL, 845.5±301.4 ng/mL, and 30.6±33.0 ng/m, respectively. The breast milk folate levels of mothers who were supplemented with folic acid during pregnancy were significantly higher compared with mothers who were not supplemented with folic acid (psupplemented with folic acid had higher follow-up serum folate levels compared with the basal level in all groups, but there was no statistically significant difference between the groups. This study showed that the folic acid doses of 25, 50, and 75 μcg/d affected serum folate levels similarly. We can conclude that the dose of 25

  20. Trend analysis of precipitation in Jharkhand State, India. Investigating precipitation variability in Jharkhand State

    Science.gov (United States)

    Chandniha, Surendra Kumar; Meshram, Sarita Gajbhiye; Adamowski, Jan Franklin; Meshram, Chandrashekhar

    2017-10-01

    Jharkhand is one of the eastern states of India which has an agriculture-based economy. Uncertain and erratic distribution of precipitation as well as a lack of state water resources planning is the major limitation to crop growth in the region. In this study, the spatial and temporal variability in precipitation in the state was examined using a monthly precipitation time series of 111 years (1901-2011) from 18 meteorological stations. Autocorrelation and Mann-Kendall/modified Mann-Kendall tests were utilized to detect possible trends, and the Theil and Sen slope estimator test was used to determine the magnitude of change over the entire time series. The most probable change year (change point) was detected using the Pettitt-Mann-Whitney test, and the entire time series was sub-divided into two parts: before and after the change point. Arc-Map 9.3 software was utilized to assess the spatial patterns of the trends over the entire state. Annual precipitation exhibited a decreasing trend in 5 out of 18 stations during the whole period. For annual, monsoon and winter periods of precipitation, the slope test indicated a decreasing trend for all stations during 1901-2011. The highest variability was observed in post-monsoon precipitation (77.87 %) and the lowest variability was observed in the annual series (15.76 %) over the 111 years. An increasing trend in precipitation in the state was found during the period 1901-1949, which was reversed during the subsequent period (1950-2011).

  1. In-Drift Precipitates/Salts Model

    Energy Technology Data Exchange (ETDEWEB)

    P. Mariner

    2004-11-09

    This report documents the development and validation of the in-drift precipitates/salts (IDPS) model. The IDPS model is a geochemical model designed to predict the postclosure effects of evaporation and deliquescence on the chemical composition of water within the Engineered Barrier System (EBS) in support of the Total System Performance Assessment for the License Application (TSPA-LA). Application of the model in support of TSPA-LA is documented in ''Engineered Barrier System: Physical and Chemical Environment Model'' (BSC 2004 [DIRS 169860]). Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration (BSC 2004 [DIRS 171156]) is the technical work plan (TWP) for this report. It called for a revision of the previous version of the report (BSC 2004 [DIRS 167734]) to achieve greater transparency, readability, data traceability, and report integration. The intended use of the IDPS model is to estimate and tabulate, within an appropriate level of confidence, the effects of evaporation, deliquescence, and potential environmental conditions on the pH, ionic strength, and chemical compositions of water and minerals on the drip shield or other location within the drift during the postclosure period. Specifically, the intended use is as follows: (1) To estimate, within an appropriate level of confidence, the effects of evaporation and deliquescence on the presence and composition of water occurring within the repository during the postclosure period (i.e., effects on pH, ionic strength, deliquescence relative humidity, total concentrations of dissolved components in the system Na-K-H-Mg-Ca-Al-Cl-F-NO{sub 3}-SO{sub 4}-Br-CO{sub 3}-SiO{sub 2}-CO{sub 2}-O{sub 2}-H{sub 2}O, and concentrations of the following aqueous species that potentially affect acid neutralizing capacity: HCO{sub 3}{sup -}, CO{sub 3}{sup 2-}, OH{sup -}, H{sup +}, HSO{sub 4}{sup -}, Ca{sup 2+}, Mg{sup 2+}, CaHCO{sub 3}{sup +}, MgHCO{sub 3

  2. Epileptic Activity Increases Cerebral Amino Acid Transport Assessed by 18F-Fluoroethyl-l-Tyrosine Amino Acid PET: A Potential Brain Tumor Mimic.

    Science.gov (United States)

    Hutterer, Markus; Ebner, Yvonne; Riemenschneider, Markus J; Willuweit, Antje; McCoy, Mark; Egger, Barbara; Schröder, Michael; Wendl, Christina; Hellwig, Dirk; Grosse, Jirka; Menhart, Karin; Proescholdt, Martin; Fritsch, Brita; Urbach, Horst; Stockhammer, Guenther; Roelcke, Ulrich; Galldiks, Norbert; Meyer, Philipp T; Langen, Karl-Josef; Hau, Peter; Trinka, Eugen

    2017-01-01

    O-(2-(18)F-fluoroethyl)-l-tyrosine ((18)F-FET) PET is a well-established method increasingly used for diagnosis, treatment planning, and monitoring in gliomas. Epileptic activity, frequently occurring in glioma patients, can influence MRI findings. Whether seizures also affect (18)F-FET PET imaging is currently unknown. The aim of this retrospective analysis was to investigate the brain amino acid metabolism during epileptic seizures by (18)F-FET PET and to elucidate the pathophysiologic background. Ten patients with 11 episodes of serial seizures or status epilepticus, who underwent MRI and (18)F-FET PET, were studied. The main diagnosis was glioma World Health Organization grade II-IV (n = 8); 2 patients suffered from nonneoplastic diseases. Immunohistochemical assessment of LAT1/LAT2/CD98 amino acid transporters was performed in seizure-affected cortex (n = 2) and compared with glioma tissues (n = 3). All patients exhibited increased seizure-associated strict gyral (18)F-FET uptake, which was reversible in follow-up studies or negative shortly before and without any histologic or clinical signs of tumor recurrence. (18)F-FET uptake corresponded to structural MRI changes, compatible with cortical vasogenic and cytotoxic edema, partial contrast enhancement, and hyperperfusion. Patients with prolonged postictal symptoms lasting up to 8 wk displayed intensive and widespread (≥ 1 lobe) cortical (18)F-FET uptake. LAT1/LAT2/CD98 was strongly expressed in neurons and endothelium of seizure-affected brains and less in reactive astrocytosis. Seizure activity, in particular status epilepticus, increases cerebral amino acid transport with a strict gyral (18)F-FET uptake pattern. Such periictal pseudoprogression represents a potential pitfall of (18)F-FET PET and may mimic brain tumor. Our data also indicate a seizure-induced upregulation of neuronal, endothelial, and less astroglial LAT1/LAT2/CD98 amino acid transporter expression. © 2017 by the Society of Nuclear

  3. Particle precipitation in connection with KOH etching of silicon

    DEFF Research Database (Denmark)

    Nielsen, Christian Bergenstof; Christensen, Carsten; Pedersen, Casper

    2004-01-01

    not removed, the iron oxide particles cause etch pits on the Si surface when later processed and exposed to phosphoric acid. It has been found that the particles can be removed in an HCl solution, but not completely in an H2SO4- H2O2 solution. The paper discusses the involved precipitation mechanism in terms......This paper considers the precipitation of iron oxide particles in connection with the KOH etching of cavities in silicon wafers. The findings presented in this paper suggest that the source to the particles is the KOH pellets used for making the etching solution. Experiments show...... that the precipitation is independent of KOH etching time, but that the amount of deposited material varies with dopant type and dopant concentration. The experiments also suggest that the precipitation occurs when the silicon wafers are removed from the KOH etching solution and not during the etching procedure. When...

  4. Alterations of thorium oxalate morphology by changing elementary precipitation conditions

    Science.gov (United States)

    Tyrpekl, V.; Beliš, M.; Wangle, T.; Vleugels, J.; Verwerft, M.

    2017-09-01

    Oxalates of actinide elements are widely used in research and industry mainly due to their low solubility in aqueous solution and easy conversion to oxide. Although thorium oxide is worldwide mostly produced by the oxalate precipitation and conversion route, the powder morphology obtained through this process is known to inhibit the packing and sintering step of the pellet production. The presented work investigates the effects of oxalate precipitation conditions on the final powder morphology. Among the precipitation conditions considered are: pH of the thorium feed solution, concentration, temperature and the order of addition (thorium solution in oxalic acid solution and vice versa) known as reverse/direct strike. Herein, we show that the morphology of the final oxalate depends significantly on the above mentioned precipitation parameters.

  5. In-situ electrochemical measurements of total concentration and speciation of heavy metals in acid mine drainage (AMD): assessment of the use of anodic stripping voltammetry.

    Science.gov (United States)

    Jung, Hun-Bok; Yun, Seong-Taek; Kim, Soon-Oh; Jung, Myung Chae; So, Chil-Sup; Koh, Yong-Kwon

    2006-06-01

    We assessed the use of anodic stripping voltammetry (ASV) for in-situ determinations of both total concentration and speciation of dissolved heavy metals (Cd, Cu, Pb and Zn) in acid mine drainage (AMD). In the Kwangyang Au-Ag mine area of South Korea, different sites with varying water chemistry within an AMD were studied with a field portable anodic stripping voltammeter. Anodic stripping voltammetry after wet oxidation (acidification) was very sensitive enough to determine total concentration of dissolved Cd because Cd was dominantly present as 'labile' species, whilst the technique was not so effective for determining total Cu especially in the downstream sites from the retention pond, due to its complexation with organic matter. For dissolved Pb, the concentrations determined by ASV after wet oxidation generally agreed with those by ICP-AES. In the downstream samples (pH>5), however, ASV data after wet oxidation were lower than ICP-AES data because a significant fraction of dissolved Pb was present in those samples as 'inert' species associated with colloidal iron oxide particles. The determination of total dissolved Zn by ASV after wet oxidation appeared to be unsatisfactory for the samples with high Cu content, possibly due to the interference by the formation of Zn-Cu intermetallic compounds on the mercury coated electrode. In AMD samples with high dissolved iron, use of ultraviolet irradiation was not effective for determining total concentrations because humate destruction by UV irradiation possibly resulted in the removal of a part of dissolved heavy metals from waters through the precipitation of iron hydroxides.

  6. The assessment of acid-base analysis: comparison of the “traditional” and the “modern” approaches

    Directory of Open Access Journals (Sweden)

    Jasna Todorović

    2015-02-01

    Full Text Available Three distinct approaches are currently used in assessing acid-base disorders: the traditional - physiological or bicarbonate-centered approach, the base-excess approach, and the “modern” physicochemical approach proposed by Peter Stewart, which uses the strong ion difference (particularly the sodium chloride difference and the concentration of nonvolatile weak acids (particularly albumin and partial pressure of carbon dioxide (pCO2 as independent variables in the assessment of acid-base status. The traditional approach developed from the pioneering work of Henderson and Hasselbalch and the base-excess are still most widely used in clinical practice, even though there are a number of problems identified with this approach. The approach works well clinically and is recommended for use whenever serum total protein, albumin and phosphate concentrations are normal. Although Stewart’s approach has been largely ignored by physiologists, it is increasingly used by anesthesiologists and intensive care specialists, and is recommended for use whenever serum’s total protein, albumin or phosphate concentrations are markedly abnormal, as in critically ill patients. Although different in their concepts, the traditional and modern approaches can be seen as complementary, giving in principle, the same information about the acid-base status.

  7. Technology and safety assessment for lactic acid bacteria isolated from traditional Bulgarian fermented meat product "lukanka"

    National Research Council Canada - National Science Library

    Svetoslav Dimitrov Todorov; Saso Stojanovski; Ilia Iliev; Penka Moncheva; Luis Augusto Nero; Iskra Vitanova Ivanova

    2017-01-01

    ... (growth at different temperature, pH, and proteolytic activity). The presence of genes related to the virulence factors, production of biogenic amines, and vancomycin resistance were presented in low frequency in the studied lactic acid bacteria...

  8. Sustainability assessment of succinic acid production technologies from biomass using metabolic engineering

    OpenAIRE

    Morales M.; Ataman M.; Badr S.; Linster S.; Kourlimpinis I.; Papadokonstantakis S.; Hatzimanikatis V.; Hungerbühlera K.

    2016-01-01

    Over the past few years bio succinic acid from renewable resources has gained increasing attention as a potential bio derived platform chemical for the detergent/surfactant ion chelator food and pharmaceutical markets. Until now much research was undertaken to lower the production costs of bio succinic acid however a multicriteria sustainability evaluation of established and upcoming production processes from a technical perspective is still lacking in the scientific literature. In this study...

  9. Assessing Folic Acid Awareness and its Usage for the Prevention of ...

    African Journals Online (AJOL)

    The common sources of information about folic acid were health workers (68.5%) and the media (14.6%). Only 26.5% (93/351) of them could correctly identify a natural source of food rich in folic acid. Multivariate logistic regression showed that maternal age >30 years (P=0.01) and higher educational status (P=0.001) were ...

  10. Characterizing differences in precipitation regimes of extreme wet and dry years: Implications for climate change experiments

    OpenAIRE

    Knapp, AK; Hoover, DL; Wilcox, KR; Avolio, ML; Koerner, SE; La Pierre, KJ; Loik, ME; Luo, Y; Sala, OE; Smith, MD

    2015-01-01

    © 2015 John Wiley & Sons Ltd. Climate change is intensifying the hydrologic cycle and is expected to increase the frequency of extreme wet and dry years. Beyond precipitation amount, extreme wet and dry years may differ in other ways, such as the number of precipitation events, event size, and the time between events. We assessed 1614 long-term (100 year) precipitation records from around the world to identify key attributes of precipitation regimes, besides amount, that distinguish statist...

  11. Safety Assessment of Formic Acid and Sodium Formate as Used in Cosmetics.

    Science.gov (United States)

    Johnson, Wilbur; Heldreth, Bart; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    2016-11-01

    Formic acid functions as a fragrance ingredient, preservative, and pH adjuster in cosmetic products, whereas sodium formate functions as a preservative. Because of its acidic properties, formic acid is a dermal and ocular irritant. However, when used as a pH adjuster in cosmetic formulations, formic acid will be neutralized to yield formate salts, for example, sodium formate, thus minimizing safety concerns. Formic acid and sodium formate have been used at concentrations up to 0.2% and 0.34%, respectively, with hair care products accounting for the highest use concentrations of both ingredients. The low use concentrations of these ingredients in leave-on products and uses in rinse-off products minimize concerns relating to skin/ocular irritation or respiratory irritation potential. The Cosmetic Ingredient Review Expert Panel concluded that formic acid and sodium formate are safe in the present practices of use and concentration in cosmetics, when formulated to be nonirritating. © The Author(s) 2016.

  12. Efficacy Assessment of Nucleic Acid Decontamination Reagents Used in Molecular Diagnostic Laboratories.

    Science.gov (United States)

    Fischer, Melina; Renevey, Nathalie; Thür, Barbara; Hoffmann, Donata; Beer, Martin; Hoffmann, Bernd

    2016-01-01

    The occurrence of nucleic acid cross contamination in the laboratory resulting in false positive results of diagnostic samples is seriously problematic. Despite precautions to minimize or even avoid nucleic acid cross contaminations, it may appear anyway. Until now, no standardized strategy is available to evaluate the efficacy of commercially offered decontamination reagents. Therefore, a protocol for the reliable determination of nucleic acid decontamination efficacy using highly standardized solution and surface tests was established and validated. All tested sodium hypochlorite-based reagents proved to be highly efficient in nucleic acid decontamination even after short reaction times. For DNA Away, a sodium hydroxide-based decontamination product, dose- and time-dependent effectiveness was ascertained. For two other commercial decontamination reagents, the phosphoric acid-based DNA Remover and the non-enzymatic reagent DNA-ExitusPlus™ IF, no reduction of amplifiable DNA/RNA was observed. In conclusion, a simple test procedure for evaluation of the elimination efficacy of decontamination reagents against amplifiable nucleic acid is presented.

  13. Co-precipitation of dissolved organic matter by calcium carbonate in Pyramid Lake, Nevada

    Science.gov (United States)

    Leenheer, Jerry A.; Reddy, Michael M.

    2008-01-01

    Our previous research has demonstrated that dissolved organic matter (DOM) influences calcium carbonate mineral formation in surface and ground water. To better understand DOM mediation of carbonate precipitation and DOM co-precipitation and/or incorporation with carbonate minerals, we characterized the content and speciation of DOM in carbonate minerals and in the lake water of Pyramid Lake, Nevada, USA. A 400-gram block of precipitated calcium carbonate from the Pyramid Lake shore was dissolved in 8 liters of 10% acetic acid. Particulate matter not dissolved by acetic acid was removed by centrifugation. DOM from the carbonate rock was fractionated into nine portions using evaporation, dialysis, resin adsorption, and selective precipitations to remove acetic acid and inorganic constituents. The calcium carbonate rock contained 0.23% DOM by weight. This DOM was enriched in polycarboxylic proteinaceous acids and hydroxy-acids in comparison with the present lake water. DOM in lake water was composed of aliphatic, alicyclic polycarboxylic acids. These compound classes were found in previous studies to inhibit calcium carbonate precipitation. DOM fractions from the carbonate rock were 14C-age dated at about 3,100 to 3,500 years before present. The mechanism of DOM co-precipitation and/or physical incorporation in the calcium carbonate is believed to be due to formation of insoluble calcium complexes with polycarboxylic proteinaceous acids and hydroxy-acids that have moderately large stability constants at the alkaline pH of the lake. DOM co-precipitation with calcium carbonate and incorporation in precipitated carbonate minerals removes proteinaceous DOM, but nearly equivalent concentrations of neutral and acidic forms of organic nitrogen in DOM remain in solution. Calcium carbonate precipitation during lime softening pretreatment of drinking water may have practical applications for removal of proteinaceous disinfection by-product precursors.

  14. Risk assessments of aspartame, acesulfame K, sucralose and benzoic acid from soft drinks, "saft", nectar and flavoured water

    OpenAIRE

    Norwegian Scientific Committee for Food Safety

    2014-01-01

    The Norwegian Scientific Committee for Food Safety (VKM) has at the request of the Norwegian Food Safety Authority conducted a risk assessment of the intense sweeteners aspartame, acesulfame K and sucralose and the preservative benzoic acid from soft drinks, “saft”, nectar and flavoured water. VKM concludes that for all age groups in all scenarios the intake of sweeteners is well below the established ADI valu