WorldWideScience

Sample records for acid precipitation assessment

  1. Economic valuation of acidic deposition damages: Preliminary results from the 1985 NAPAP [National Acid Precipitation Assessment Program] damage assessment

    This paper identifies methods used to evaluate the economic damages of acid deposition in the 1985 Damage Assessment being coordinated by the National Acid Precipitation Program. It also presents the preliminary estimates of economic damages for the Assessment. Economic damages are estimated for four effect areas: commercial agriculture and forests, recreational fishing and selected types of materials. In all but the last area, methods are used which incorporate the behavioral responses of individuals and firms or simulated physical damages to resources at risk. The preliminary nature of the estimated damages in each area is emphasized. Over all, the damage estimates should be interpreted with caution. 44 refs., 6 figs., 5 tabs

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

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

    Vet, Robert; Pienaar, Jacobus J.; Artz, Richard S.; Carou, Silvina; Shaw, Mike; Ro, Chul-Un; Aas, Wenche

    2014-01-01

    A global assessment of precipitation chemistry and deposition has been carried out under the direction of the World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) Scientific Advisory Group for Precipitation Chemistry (SAG-PC). The assessment addressed three questions: (1) what do measurements and model estimates of precipitation chemistry and wet, dry and total deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity, and phosphorus show glob...

  4. Acid precipitation and scientific fallout

    U.S. Senator Daniel Patrick Moynihan from New York believes the nation should set its environmental policies based upon knowledge of the costs and benefits of such policies. For that reason, he defends the National Acid Precipitation Assessment Program (NAPAP), despite the program's lack of influence on recent clean-air legislation. open-quotes Environmentalism is nothing if not an ethic of responsibility,close quotes Senator Moynihan writes, open-quotes and our first responsibility is to the facts-facts about costs and facts about benefits. It is not knowledge that we should fear, but the lack of knowledge.close quotes Despite its lack of timeliness and its failure to effectively communicate its findings to laymen, NAPAP provided that knowledge about the effects of acid rain, the senator maintains. open-quotes NAPAP has given us 10 years of data,close quotes he says. open-quotes Ten years from now, we will have 20 years of data, and 30 years from now we will have 40 years of data, and we will know something about what happens when we intervene in the natural environment. We will know some of the costs and some of the benefits.close quotes

  5. Generation of dose-response relationships to assess the effects of acidity in precipitation on growth and productivity of vegetation

    Experiments were performed with several plant species in natural environments as well in a greenhouse and/or tissue culture facilities to establish dose-response functions of plant responses to simulated acidic rain in order to determine environmental risk assessments to ambient levels of acidic rain. Response functions of foliar injury, biomass of leaves and seed of soybean and pinto beans, root yields of radishes and garden beets, and reproduction of bracken fern are considered. The dose-response function of soybean seed yields with the hydrogen ion concentration of simulated acidic rainfalls was expressed by the equation y = 21.06-1.01 log x where y = seed yield in grams per plant and x = the hydrogen concentration if μeq l-1. The correlation coefficient of this relationship was -0.90. A similar dose-response function was generated for percent fertilization of ferns in a forest understory. When percent fertilization is plotted on logarithmic scale with hydrogen ion concentration of the simulated rain solution, the Y intercept is 51.18, slope -0.041 with a correlation coefficient of -0.98. Other dose-response functions were generated that assist in a general knowledge as to which plant species and which physiological processes are most impacted by acidic precipitation. Some responses did not produce convenient dose-response relationships. In such cases the responses may be altered by other environmental factors or there may be no differences among treatment means

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

    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. PMID:20471746

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

    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

  8. Acid Precipitation and the Forest Ecosystem

    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)

  9. Acid precipitation in Europe and Asia

    The article surveys acid precipitation problems in the region, discusses the sources, the pollutant composition and distribution, the work with the RAINS models as well as the organisation of and the results of joint incentives in the region. The acidification problems in China and some of the Norwegian participation efforts are reviewed. The author points out that much of the acidic precipitation and the environmental problems in Eurasia are due to the use of coal rich in sulphur, that the energy and environmental policies differs throughout the region because of differences in ecology and development levels and that Asia is far more heterogeneous than Europe as to the conditions for co-ordinated efforts against acid precipitation. The differences in economy, geopolitical situation, environmental policies etc. are larger than in Europe and a considerable international effort will be required in order to succeed. Should the regional model RAINS-Asia be used as basis for further co-ordinated efforts on acid precipitation thorough evaluations on costs and advantages are needed. The conditions and need for modelling as basis for international agreements between Asiatic countries are not the same as in Europe. Finally international development organisations have and will continue to play an important part in the work for reducing acid precipitation in Asia. The Asiatic countries may also greatly benefit in the battle against acid precipitation from the experiences of the industrialised countries. However, Asiatic countries will have to meet the major costs of emission reduction themselves. The main question is what emphasis will be put on the long term environmental profits and on the need for rapid economic growth of materially impoverished people. Other development directions than those used by the industrialised countries, seems to be needed

  10. Biologically produced acid precipitable polymeric lignin

    Crawford, Don L.; Pometto, III, Anthony L.

    1984-01-01

    A water soluble, acid precipitable polymeric degraded lignin (APPL), having a molecular weight of at least 12,000 daltons, and comprising, by percentage of total weight, at least three times the number of phenolic hydroxyl groups and carboxylic acid groups present in native lignin. The APPL may be modified by chemical oxidation and reduction to increase its phenolic hydroxyl content and reduce the number of its antioxidant inhibitory side chains, thereby improving antioxidant properties.

  11. Wet precipitators for sulphuric acid plants

    Both the service requirements and design construction details have changed considerably in recent years for wet electrostatic precipitators as used for gas cleaning ahead of metallurgical sulphuric acid plants. Increased concern over acid quality has resulted in more emphasis on dust efficiencies compared to collection of acid mist. Also, higher static operating pressures have caused large structural loads on casing and internal components. In this paper these two issues are addressed in the following ways: Recognition that all dusts do not collect similarly. The mechanism by which various dusts collect affect the design of the entire wet gas cleaning system. Use of both traditional and newer materials of construction to accommodate the higher design pressures while still maintaining corrosion resistance

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

    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

  13. Ten-year study on acid precipitation nears conclusion

    Results from the National Acid Precipitation Assessment Program (NAPAP) are discussed. Final results are contained in 26 state of the science reports. Seven of the reports provide information on acid rain and aquatic ecosystems. They describe the current state of acidic surface waters, watershed processes affecting surface water chemistry, historical evidence for surface water acidification, methods for forecasting future changes, and the response of acidic surface water to liming. Six areas of the country were found to be of special interest: southwest Adirondacks, New England, forested areas of the mid-Atlantic highlands, the Atlantic coastal plain, the northern Florida highlands, parts of northeastern Wisconsin and the Upper Peninsula of Michigan. Environmental effects, mitigation efforts and possible legislation are briefly discussed

  14. Precipitation of humic acid with divalent ions

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

    2001-01-01

    HA concentration. With respect to region III, it is not exclusively determined whether precipitation is caused by HA behaving as a polyelectrolyte or possessing colloidal properties. The general observation throughout is that HA appears to behave as a polyelectrolyte at low concentrations and...

  15. Tracing of salicylic acid additive during precipitation of zirconium

    This paper presents the results of experimental study carried out to know whether the salicylic acid used as an additive during the precipitation of zirconium using ammonium hydroxide solution goes into the filtrate, remains in the hydrated zirconia or gets distributed between the both under the ambient conditions of precipitation. Keeping its simplicity and amenability to adopt on a routine basis, spectrophotometric method has been chosen for the purpose among the many methods available and the problems associated in determining salicylic acid in the presence of zirconium and the medial measures to circumvent the same have been brought out in detail. (author)

  16. Effects of acidic precipitation on vegetation

    Jacobson, J.S.; van Leuken, P.

    1977-01-01

    An experimental study of the effect of simulated acidic rain on greenhouse and field grown conifers and herbaceous vegetation was conducted. Pinus strobus (Eastern white pine), P. sylvestris (Scotch pine), Helianthus annus (sunflower), Phaseolus vulgaris (bean) and Spinacea oleracea (spinach) were sprayed with simulated rain. pH of solutions was adjusted by H/sub 2/SO/sub 4/ and HNO/sub 3/ to a range of 2.2 to 3.4. Plants were examined for injury following completion of treatment(s). Symptoms consisted of necrotic lesions. On pine, lesions developed at the apical and mid-portion of needles. Dormant conifers were tolerant while injury developed more readily on older needles. White pine was more susceptible than Scotch pine. On bean leaves, lesions were scattered over the leaf and were tan to dark brown. Symptoms on sunflower and spinach leaves consisted of light brown irregularly shaped lesions. Foliar injury to herbaceous plants increased with increasing treatment time and acidity. Injury was induced at pH 2.6 after one minute, at pH 3.0 after 1.5 hours, at pH 3.2 after 3 hours and at pH 3.4 after 9 hours. No aberrant growth or development was observed in conifers. Necrosis is the typical response to acidic rain. A relationship between treatment duration and pH is drawn. It shows that long duration at a pH as high as 3.4 can produce necrosis of herbaceous species. Herbaceous species are more susceptible than conifers.

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

    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.

  18. Precipitation of plutonium from acidic solutions using magnesium oxide

    Magnesium oxide will be used as a neutralizing agent for acidic plutonium-containing solutions. It is expected that as the magnesium oxide dissolves, the pH of the solution will rise, and plutonium will precipitate. The resulting solid will be tested for suitability to storage. The liquid is expected to contain plutonium levels that meet disposal limit requirements

  19. Arsenic removal from acidic solutions with biogenic ferric precipitates.

    Ahoranta, Sarita H; Kokko, Marika E; Papirio, Stefano; Özkaya, Bestamin; Puhakka, Jaakko A

    2016-04-01

    Treatment of acidic solution containing 5g/L of Fe(II) and 10mg/L of As(III) was studied in a system consisting of a biological fluidized-bed reactor (FBR) for iron oxidation, and a gravity settler for iron precipitation and separation of the ferric precipitates. At pH 3.0 and FBR retention time of 5.7h, 96-98% of the added Fe(II) precipitated (99.1% of which was jarosite). The highest iron oxidation and precipitation rates were 1070 and 28mg/L/h, respectively, and were achieved at pH 3.0. Subsequently, the effect of pH on arsenic removal through sorption and/or co-precipitation was examined by gradually decreasing solution pH from 3.0 to 1.6 (feed pH). At pH 3.0, 2.4 and 1.6, the highest arsenic removal efficiencies obtained were 99.5%, 80.1% and 7.1%, respectively. As the system had ferric precipitates in excess, decreased arsenic removal was likely due to reduced co-precipitation at pH<2.4. As(III) was partially oxidized to As(V) in the system. In shake flask experiments, As(V) sorbed onto jarosite better than As(III). Moreover, the sorption capacity of biogenic jarosite was significantly higher than that of synthetic jarosite. The developed bioprocess simultaneously and efficiently removes iron and arsenic from acidic solutions, indicating potential for mining wastewater treatment. PMID:26705889

  20. Accuracy assessment of gridded precipitation datasets in the Himalayas

    Khan, A.

    2015-12-01

    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 twelve 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) NCEP / 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 data, 9) PRINCETON, 10) European Reanalysis-40 (ERA-40), 11) Willmott and Matsuura, and 12) WATCH Forcing Data based on ERA interim (WFDEI). 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 underestimate precipitation in the Karakoram sub-basins. For the Hindukush and Himalayan sub-basins most datasets underestimate precipitation, except ERA-interim and ERA-40. The analysis indicates that for this large region with complicated terrain features and stark spatial precipitation gradients the reanalysis datasets have better consistency with flow measurements than datasets derived from records of only sparsely distributed climatic

  1. Precipitation of plutonium from acidic solutions using magnesium oxide

    Plutonium (IV) is only marginally soluble in alkaline solution. Precipitation of plutonium using sodium or potassium hydroxide to neutralize acidic solutions produces a gelatinous solid that is difficult to filter and an endpoint that is difficult to control. If the pH of the solution is too high, additional species precipitate producing an increased volume of solids separated. The use of magnesium oxide as a reagent has advantages. It is added as a solid (volume of liquid waste produced is minimized), the pH is self-limiting (pH does not exceed about 8.5), and the solids precipitated are more granular (larger particle size) than those produced using KOH or NaOH. Following precipitation, the raffinate is expected to meet criteria for disposal to tank farms. The solid will be heated in a furnace to dry it and convert any hydroxide salts to the oxide form. The material will be cooled in a desiccator. The material is expected to meet vault storage criteria

  2. OCHRE PRECIPITATES AND ACID MINE DRAINAGE IN A MINE ENVIRONMENT

    BRANISLAV MÁŠA

    2012-03-01

    Full Text Available This paper is focused to characterize the ochre precipitates and the mine water effluents of some old mine adits and settling pits after mining of polymetallic ores in Slovakia. It was shown that the mine water effluents from two different types of deposits (adits; settling pits have similar composition and represent slightly acidic sulphate water (pH in range 5.60-6.05, sulphate concentration from 1160 to 1905 g.dm-3. The ochreous precipitates were characterized by methods of X-ray diffraction analysis (XRD, scanning electron microscopy (SEM and B.E.T. method for measuring the specific surface area and porosity. The dominant phases were ferrihydrite with goethite or goethite with lepidocrocide.

  3. Ochre precipitates and Acid Mine Drainage in a mine environment

    Máša, B.; Pulišová, Petra; Bezdička, Petr; Michalková, E.; Šubrt, Jan

    2012-01-01

    Roč. 56, č. 1 (2012), s. 9-14. ISSN 0862-5468 R&D Projects: GA MŠk(CZ) MEB0810136 Grant ostatní: Ministry of Education of the Slovak Republic(SK) VEGA 1/0529/09 Institutional research plan: CEZ:AV0Z40320502 Keywords : ochre precipitate * Acid Mine Drainage ( AMD ) * X-ray diffraction analysis (XRD) * Scanning electron microscopy (SEM) * specific surface area and porosity Subject RIV: CA - Inorganic Chemistry Impact factor: 0.418, year: 2012

  4. Precipitation of silicic acid from geothermal water by addition of cetyl-trimethyl-ammonium bromide

    Kitsuki, Harumi; Yokoyama, Takushi; Shimada, Kanichi; Yamanaka, Chiho; Nishu, Keisuke; Shimizu, Shin; Tarutani, Toshikazu

    1986-01-25

    Cetyl-trimethyl-ammonium bromide (CTAB) was added to sodium silicate solution and geothermal hot water (Ohtake Geothermal Power Plant and Hatchobaru Geo-thermal Power Plant) to precipitate silica. 1) CTA ions do not react with monosilicic acid, but only the polymerization among the polysilicic acids proceeds and causes silica to precipitate. Optimum pH for the silica precipitation is 6 - 7 and the higher concentration of polysilicic acid will cause more precipitation. 2) When added to geothermal hot water, the silica precipita-tion increases with the increase of CTAB concentration within the range of 10/sup -7/ - 10/sup -4/ mol dm/sup 3/ concentration. Almost all poly-silicic acid precipitated at 10/sup -4/ mol dm/sup 3/ when measured for silica precipitation after 5 minutes. Total concentration of silicic acid was higher in the Hatchobaru geothermal water than that of the Ohtake geothermal water. (10 figs, 14 refs)

  5. The effect of scale in daily precipitation hazard assessment

    Egozcue, J. J.; Pawlowsky-Glahn, V.; Ortego, M. I.; Tolosana-Delgado, R.

    2006-06-01

    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.

  6. The effect of scale in daily precipitation hazard assessment

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

    W. Huang; 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 organic P mineralization potential in soils. In order to study the effects of precipitation on soil acid phosphatase activity, an experiment with precipitation t...

  8. Indium sulfide precipitation from hydrochloric acid solutions of calcium and sodium chlorides

    The effect of precipitation duration, acid concentration, indium complexing with chloride ions on the process of indium sulfide chemical precipitation in hydrochloric acid solutions, precipitate composition and dispersity are studied. It is established that indium sulfide solubility increases in solutions with acid concentration exceeding 0.40-0.45 mol/l. Calcium and indium chloride addition to diluted hydrochloric solutions greatly increases the solubility of indium sulfide. The effect of calcium chloride on In2S3 solubility is higher than that of sodium chloride

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

    W. Huang

    2011-07-01

    Full Text Available 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.

  10. Influence of acid precipitation on bacterial populations in lakes

    Rao, S.S.; Dutka, B.J.

    1983-01-01

    Relative abundance of total, respiring, aerobic heterotrophic, nitrogen cycle and sulfur cycle bacteria was measured in acid stressed and non-acid stressed hardwater lakes. Data indicated that bacterial populations and densities were nearly an order of magnitude less in acid stressed waters than in non-acid stressed waters. Nitrifying bacteria and some sulfur cycle bacteria (Thiobacillus sp.) were very low or absent in acid stressed waters. Surface sediments of acid stressed lakes contained 3 to 4 times more organic matter than the amount found in the relatively more enriched lake. Methodology and data are presented. 20 references, 1 figure, 1 table.

  11. Struvite Precipitation for Ammonia Nitrogen Removal in 7-Aminocephalosporanic Acid Wastewater

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

    2012-01-01

    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 resu...

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

    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

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

    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 correlat...

  14. Impacts of acid precipitation on decomposition and plant communities in lakes

    Hendrey, G R; Barvenik, F W

    1978-01-01

    Over the past few decades the acidity of lakes and rivers has been increasing in several areas of the world. In southern Norway, western Sweden, the Canadian Shield, and the northeastern United States, acidification of fresh waters has become a major environmental problem. It has been clearly established that acid precipitation is the cause of decreasing pH levels in waters of the affected areas. Over most all of northern Europe, southern Scandinavia, and essentiallly all of the U.S. east of the Mississippi River, the mean annual H/sup +/ concentrations in precipitation, expressed as pH, are below 5.0. Furthermore, the regions affected by very acid precipitation (pH < 4.5) are rapidly expanding. The effects of acid precipitation on aquatic ecosystems depend primarily on the geology of the region, but also on the evaluation (orographic precipitation). The regions now known to be the most seriously affected are mountainous districts of southern Scandinavia and the northeastern United States which are located hundreds of kilometers from SO/sub 2/ and NO/sub x/ emissions sources. Regions of the United States which are potentially sensitive to acid inputs because of their geology and surface water alkalinity are also found in the western United States. Local acid precipitation problems are now known on the West Coast, and some lakes in the Puget Sound region appear to be acidified aquatic flora and fauna at all ecosystem levels are greatly impoverished in acidified freshwaters. The numbers of species are reduced and changes in the biomass of some groups of plants and animals have been observed. Decomposition of leaf litterand other organic substrates is hampered, nutrient recycling appears to be retarded, and nitrofication inhibited at pH levels frequently observed in acid-stressed waters.

  15. Composition and hygroscopicity of aerosol particles at Mt. Lu in South China: Implications for acid precipitation

    Li, Weijun; Chi, Jianwei; Shi, Zongbo; Wang, Xinfeng; Chen, Bin; Wang, Yan; Li, Tao; Chen, Jianmin; Zhang, Daizhou; Wang, Zifa; Shi, Chune; Liu, Liangke; Wang, Wenxing

    2014-09-01

    Physicochemical properties of aerosol particles were studied at Mt. Lu, an elevated site (115°59‧E, 29°35‧N, 1165 m) within the acid precipitation area. Northeast winds transport copious amounts of air pollutants and water vapor from the Yangtze River Delta into this acid precipitation area. NH4+ and SO42- are the dominant ions in PM2.5 and determine aerosol acidity. Individual particle analysis shows abundant S-rich and metals (i.e. Fe-, Zn-, Mn-, and Pb-rich) particles. Unlike aerosol particles in North China and urban areas, there are little soot and mineral particles at Mt. Lu. Lack of mineral particles contributed to the higher acidity in precipitation in the research area. Nano-sized spherical metal particles were observed to be embedded in 37% of S-rich particles. These metal particles were likely originated from heavy industries and fired-power plants. Hygroscopic experiments show that most particles start to deliquesce at 73-76% but organic coating lowers the particle deliquescence relative humidity (DRH) to 63-73%. The DRHs of these aerosol particles are clearly smaller than that of pure ammonium sulfate particles which is 80%. Since RH in ambient air was relatively high, ranging from 65% to 85% during our study period, most particles at our sampling site were in liquid phase. Our results suggest that liquid phase reactions in aerosol particles may contribute to SO2 to sulfuric acid conversion in the acid precipitation area.

  16. Precipitation rare earth elements from filtrate digestion of Bangka monazite by sulphuric acid

    Rare earth elements are elements that widely used in many products. Rare earth elements nature are not found in a free state, but they are in the complex compounds, so that chemically processing is required to separate the Rare earth elements from their complex compounds. Monazite as by product of Bangka tin process contains several major elements, such as 0.298% uranium (U). 4.171% thorium (Th), 23.712% phosphat (P2O5) and 58.97% rare earth elements (REE) oxide. These elements can be individually separated through a process of precipitation stages. The separation process used in the study is the method of acid by using sulfate acid as reagent and filtrate digestion as feeds. The process of digestion dissolve the elements U, Th, RE and phosphate from the complex compound. Rare earth elements that are dissolved can be separated from the complex compounds by using sulfate acid precipitation process. The objective of research is to set the optimal conditions for the Rare earth elements precipitation with sulfate acid. The result showed that the amount of sulphuric H2SO4 which added is 3.5 times volume of feed and precipitation time is 20 minutes. percentage of precipitation recovery is 61.21% REE, 78.46% U, and 93.56% PO4. (author)

  17. Effects of simulated acidic precipitation on the colonization and ice nucleation activity of Pseudomonas syringae pv. syringae and Erwinia herbicola

    Murray, Joseph Marshall

    1987-01-01

    Precipitation over the eastern United States has been increasing in acidity, particularly within the last three decades. The average annual pH of rain in this area is about 4.2. The foliar surface, or phylloplane, of soybean can be damaged by rain acidified to pH 2.9. Simulated acidic precipitation has an overall inhibitory influence on soil microbial processes. The effect acidic precipitation may have on epiphytic microorganisms has not been examined. Bacteria are amo...

  18. Assessment of Satellite Precipitation Products in the Philippine Archipelago

    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.

  19. Mercury Pollution of Soil—Crop System in Acid precipitation Area

    MOUSHU-SEN; QINGCHANG-LE

    1995-01-01

    In acid precipitation area of Chongqing suburb the average of Hg in soil rose from 0.158mg/kg in 1984 to 0.20mg/kg in 1989,and Hg content of crops grown on these soils increased too.Both soil and vegetable Hg came mainly from power plant emission.which caused Hg and acid precipitiation pollution in environment and the Hg pollution of water,crops and milk in the area.

  20. Fractionation of microimpurities during precipitation of basic zirconium sulfate out of nitric acid solutions

    A study was made on fractionation of microimpurities during precipitation of basic zirconium sulfate out of concentrated with respect to ZrO2 nitric acid solutions. Investigation into fractionation of Sc(3), Cr(3), Mn(2), Fe(3), Co(2), CU(2), Zn(2) and Y(3) microirpurities during hydrolytic precipitation of basic zirconium sulfate out of nitric acid solutions showed that a majority of microimpurities are characterized by high distribution factors and concentrate in mother liquor. Adsorption isotherms were constructed for Cu(2) and Fe(3) microimpurities. The assumption about the effect of microimpurity nature (ionic charge and radius, the electron structure) on precipitation mechanism was made on the base of obtained data

  1. PH BUFFERING IN FOREST SOIL ORGANIC HORIZONS: RELEVANCE TO ACID PRECIPITATION

    Samples of organic surface horizons (Oi, Oe, Oa) from New York State forest soils were equilibrated with 0 to 20 cmol HNO3 Kg(-1) soil in the laboratory by a batch technique designed to simulate reactions of acid precipitation with forest floors. Each organic horizon retained a c...

  2. Kinetic study of the precipitation of radioactive elements in the production process of phosphoric acid

    In this engineering study we determined the activities of gamma emitting radionuclides belonging to the families of 238U ,232Th and 40K in phosphate, the acid derivatives and gypsum in Tunisian Chemical Group. The most important activities are those of 238U and 226Ra, which are located in the phosphate, gypsum and the precipitates formed in the pipes.

  3. Assessing precipitation distribution impacts on droughts on the island of Crete

    Vrochidou, A.-E. K.; Tsanis, I. K.

    2012-04-01

    Precipitation records from 56 stations on the island of Crete (Greece) revealed that areal mean annual precipitation is of a strong orographic type and its magnitude decreases in west-east direction by as much as 400 mm on average. Amongst many parameters that influence precipitation, the elevation and longitude were the most important and provided the highest spatial correlation. It was found that during the year with minimum precipitation, the precipitation shortage was greater at high elevations while the precipitation excess during the year with maximum precipitation was greater in the western part of the island. The assessment of the spatial and temporal distribution of droughts was carried out with the aid of the Spatially Normalized Standardized Precipitation Index (SN-SPI) for the period 1974-2005 in order to compare drought conditions between neighbouring areas of differing precipitation heights. The analysis showed that severe droughts occurred around the year 1992-1993, with a duration of up to 3 yr. Multiple linear regression (MLR) modeling of precipitation in conjunction with cluster analysis of drought duration exhibits the linkage between precipitation, droughts and geographical factors. This connection between spatial precipitation distribution and geographical parameters provides an important clue for the respective spatial drought pattern. The above findings on the spatio-temporal drought distribution will update the current~drought management plans by developing more precise drought warning systems.

  4. Precipitation variability assessment of northeast China: Songhua River basin

    Muhammad Imran Khan; Dong Liu; Qiang Fu; Muhammad Azmat; Mingjie Luo; Yuxiang Hu; Yongjia Zhang; Faiz M Abrar

    2016-07-01

    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 precipitation data on a monthly, seasonally, annually, decade scale and the number of rainydays for each selected station. Intensity entropy and apportionment entropy were used to calculate thevariability over individual year and decade, respectively. Subsequently, Spearman’s Rho and Mann–Kendall tests were applied to observe for trends in the precipitation time series. The statistics of sampledisorder index showed that the precipitation during February (mean 1.09, max. 1.26 and min. 0.80),April (mean 1.12, max. 1.29 and min. 0.99) and July (mean 1.10, max. 1.20 and min. 0.98) contributedsignificantly higher than those of other months. Overall, the contribution of the winter season wasconsiderably high with a standard deviation of 0.10. The precipitation variability on decade basis wasobserved to increase from decade 1964–1973 and 1994–2003 with a mean value of decadal apportionmentdisorder index 0.023 and 0.053, respectively. In addition, the Mann–Kendall test value (1.90) showed asignificant positive trend only at the Shangzhi station.

  5. Future extreme precipitation assessment in Western Norway – using a linear model approach

    G. N. Caroletti

    2009-12-01

    Full Text Available The need for local assessments of precipitation has grown in recent years due to the increase in precipitation extremes and the widespread awareness about findings of the IPCC 2003 Report on climate change. General circulation models, the most commonly used tool for climate predictions, show an increase in precipitation due to an increase in greenhouse gases (Cubash and Meehl, 2001. It is suggested that changes in extreme precipitation are easier to detect and attribute to global warming than changes in mean annual precipitation (Groisman et al., 2005. However, because of their coarse resolution, the global models are not suited to local assessments. Thus, downscaling of data is required.

    A Linear Model (Smith and Barstad, 2004 is used to dynamically downscale orographic precipitation over Western Norway from twelve General Circulation Model simulations based on the A1B emissions scenario (IPCC, 2003. An assessment of the changes to future Orographic Precipitation (2046–2065 and 2081–2100 time periods versus the historical control period (1971–2000 is carried out. Results show an increased number of Orographic Precipitation days and an increased Orographic Precipitation intensity. Extreme precipitation events are up to 20% more intense than the 1971–2000 values. Extremes are defined by the exceedence of the 99%-ile threshold in the time slice. Using station-based observations from the control period, the results from downscaling can be used to generate simulated precipitation histograms at selected stations.

    The Linear Model approach also allows for simulated changes in precipitation to be disaggregated according to their causal source: (a the role of topography and (b changes to the amount of moisture delivery to the site. The latter can be additionaly separated into moisture content changes due to: (i temperature; (ii wind speed; (iii stability. An analysis of these results suggests a strong role for warming in

  6. Oxidative Precipitation of Manganese from Acid Mine Drainage by Potassium Permanganate

    Regeane M. Freitas

    2013-01-01

    Full Text Available Although oxidative precipitation by potassium permanganate is a widely recognised process for manganese removal, research dealing with highly contaminated acid mine drainage (AMD has yet to be performed. The present study investigated the efficiency of KMnO4 in removing manganese from AMD effluents. Samples of AMD that originated from inactive uranium mine in Brazil were chemically characterised and treated by KMnO4 at pH 3.0, 5.0, and 7.0. Analyses by Raman spectroscopy and geochemical modelling using PHREEQC code were employed to assess solid phases. Results indicated that the manganese was rapidly oxidised by KMnO4 in a process enhanced at higher pH. The greatest removal, that is, 99%, occurred at pH 7.0, when treated waters presented manganese levels as low as 1.0 mg/L, the limit established by the Brazilian legislation. Birnessite (MnO2, hausmannite (Mn3O4, and manganite (MnOOH were detected by Raman spectroscopy. These phases were consistently identified by the geochemical model, which also predicted phases containing iron, uranium, manganese, and aluminium during the correction of the pH as well as bixbyite (Mn2O3, nsutite (MnO2, pyrolusite (MnO2, and fluorite (CaF2 following the KMnO4 addition.

  7. Struvite Precipitation for Ammonia Nitrogen Removal in 7-Aminocephalosporanic Acid Wastewater

    Erhong Duan

    2012-02-01

    Full Text Available 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:PO43−-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 PO43−-P in the effluent. MgCl2·6H2O + 85% H3PO4 was the most efficient combination for NH4+-N removal. Furthermore, the lowest concentration of the residual PO43−-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.

  8. Online Assessment of Satellite-Derived Global Precipitation Products

    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

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

    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.

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

    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 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. PMID:20430523

  11. Distinguishing between carbonate and non-carbonate precipitates from the carbonation of calcium-containing organic acid leachates

    Santos, Rafael; Chiang, Yi Wai; Elsen, Jan; Van Gerven, Tom

    2014-01-01

    Two organic acids were trialled for the extraction of calcium from steelmaking blast furnace slag for the purpose of precipitated calcium carbonate (PCC) production: succinic and acetic acids. While the leaching performance of succinic acid was superior, carbonation of its leachate did not result in the production of PCC, but rather the precipitation of calcium succinate, and only after the use of pH buffering agents (sodium hydroxide or bicarbonate). In contrast, carbonation of the acetic ac...

  12. Nitric acid adduct formation during crystallization of barium and strontium nitrates and their co-precipitation from nitric acid media

    The molar solubilities of Ba, Sr and Pb nitrates in nitric acid as a function of total nitrate concentration is presented and described by the mass action law, indicating on formation of the adducts with nitric acid. Precipitates of Ba(NO3)2 and Sr(NO3)2 crystallized from nitric acid were studied by ISP OES and IR spectroscopy. The data obtained confirmed formation of metastable adducts with nitric acid. IR and X-ray diffraction studies of the mixed salt systems indicated conversion of the mixed salts into (Ba,Sr)(NO3)2 solid solution of discrete structure in range of total nitrate ion concentration ∼6 mol/L. (author)

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

    Sebastian Wilhelm; Matthias Kind

    2014-01-01

    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 o...

  14. Fabrication and characterization of magnetic ferrofluids by the co-precipitation way using diglycolic acid

    Jagminas, Arunas, E-mail: jagmin@ktl.mii.lt; Kurtinaitiene, Marija; Mazeika, Kestutis [State Research Institute Center for Physical Sciences, and Technology (Lithuania); Rotomskis, Ricardas [Vilnius University, Institute of Oncology (Lithuania); Niaura, Gediminas; Selskis, Algirdas [State Research Institute Center for Physical Sciences, and Technology (Lithuania)

    2011-09-15

    Developing of a simple method for the fabrication of superparamagnetic iron oxide nanoparticles (Nps) is still a challenge for materials scientists. This work reveals a way to fabricate especially stable ferrofluids from spherical Nps of magnetite using the co-precipitation method, for which a new (diglycolic acid) stabilizer was applied. The Nps of the average size of {approx}7.4-16.5 nm were characterized by means of high resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), selective area electron diffraction (SAED), Raman, FTIR and Moessbauer spectroscopy. The stabilization effect of the diglycolic acid for the growth of superparamagnetic Nps growth was discussed on the basis of experimental results.

  15. Influence of phosphate and silica on U(VI) precipitation from acidic and neutralized wastewaters.

    Kanematsu, Masakazu; Perdrial, Nicolas; Um, Wooyong; Chorover, Jon; O'Day, Peggy A

    2014-06-01

    Uranium speciation and physical-chemical characteristics were studied in solids precipitated from synthetic acidic to circumneutral wastewaters in the presence and absence of dissolved silica and phosphate to examine thermodynamic and kinetic controls on phase formation. Composition of synthetic wastewater was based on disposal sites 216-U-8 and 216-U-12 Cribs at the Hanford site (WA, USA). In the absence of dissolved silica or phosphate, crystalline or amorphous uranyl oxide hydrates, either compreignacite or meta-schoepite, precipitated at pH 5 or 7 after 30 d of reaction, in agreement with thermodynamic calculations. In the presence of 1 mM dissolved silica representative of groundwater concentrations, amorphous phases dominated by compreignacite precipitated rapidly at pH 5 or 7 as a metastable phase and formation of poorly crystalline boltwoodite, the thermodynamically stable uranyl silicate phase, was slow. In the presence of phosphate (3 mM), meta-ankoleite initially precipitated as the primary phase at pH 3, 5, or 7 regardless of the presence of 1 mM dissolved silica. Analysis of precipitates by U LIII-edge extended X-ray absorption fine structure (EXAFS) indicated that "autunite-type" sheets of meta-ankoleite transformed to "phosphuranylite-type" sheets after 30 d of reaction, probably due to Ca substitution in the structure. Low solubility of uranyl phosphate phases limits dissolved U(VI) concentrations but differences in particle size, crystallinity, and precipitate composition vary with pH and base cation concentration, which will influence the thermodynamic and kinetic stability of these phases. PMID:24754743

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

    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.

  17. The influence of organic compounds on the development of precipitation acidity in maritime clouds

    L. Alfonso

    2004-01-01

    Full Text Available In order to estimate the anthropogenic influence of gas and aerosol emissions from the Petroleum Industry in maritime zones with clouds of small vertical extent, a numerical 1-D Eulerian cloud-chemical model with detailed microphysics (Alfonso and Raga, 2002 is used to simulate the influence of water soluble organic compounds (WSOC and organic+inorganic gas emissions on cloud development. Following Mircea et al. (2002, we tested the sensitivity of the cloud and precipitation development in the classical inorganic case (CIC and the inorganic+organic case (IOC with respect to CCN compositions. The results indicate an increase in the droplet concentration for the IOC, and a delay in the development of precipitation. The pH spectral evolution was studied during both the development and precipitation stages. The influence of the diffusion of formic acid and its generation by oxidation of hydrated formaldehyde in the aqueous phase result in a reduction in the pH of precipitation in the range between 0.05 and 0.15 pH units (from 1 to 3% for the high ambient SO2 concentration (20 ppb and between 0.2-0.5 pH units (from 4 to 10% for the low ambient SO2 concentration (1 ppb case.

  18. Glycochenodeoxycholic acid inhibits calcium phosphate precipitation in vitro by preventing the transformation of amorphous calcium phosphate to calcium hydroxyapatite.

    Qiu, S M; Wen, G.; Hirakawa, N; Soloway, R D; Hong, N K; Crowther, R S

    1991-01-01

    Calcium hydroxyapatite can be a significant component of black pigment gallstones. Diverse molecules that bind calcium phosphate inhibit hydroxyapatite precipitation. Because glycine-conjugated bile acids, but not their taurine counterparts, bind calcium phosphate, we studied whether glycochenodeoxycholic acid inhibits calcium hydroxyapatite formation. Glycochenodeoxycholic acid (2 mM) totally inhibited transformation of amorphous calcium phosphate microprecipitates to macroscopic crystalline...

  19. High-molecular-weight polymers for protein crystallization: poly-γ-glutamic acid-based precipitants

    Hu, Ting-Chou [Department of Chemistry, University of York, York YO10 5YW (United Kingdom); Korczyńska, Justyna [Department of Chemistry, University of York, York YO10 5YW (United Kingdom); Structural Biology Laboratory, University of York, York YO10 5YW (United Kingdom); Smith, David K. [Department of Chemistry, University of York, York YO10 5YW (United Kingdom); Brzozowski, Andrzej Marek, E-mail: marek@ysbl.york.ac.uk [Department of Chemistry, University of York, York YO10 5YW (United Kingdom); Structural Biology Laboratory, University of York, York YO10 5YW (United Kingdom)

    2008-09-01

    High-molecular-weight poly-γ-glutamic acid-based polymers have been synthesized, tested and adopted for protein crystallization. Protein crystallization has been revolutionized by the introduction of high-throughput technologies, which have led to a speeding up of the process while simultaneously reducing the amount of protein sample necessary. Nonetheless, the chemistry dimension of protein crystallization has remained relatively undeveloped. Most crystallization screens are based on the same set of precipitants. To address this shortcoming, the development of new protein precipitants based on poly-γ-glutamic acid (PGA) polymers with different molecular-weight ranges is reported here: PGA-LM (low molecular weight) of ∼400 kDa and PGA-HM (high molecular weight) of >1000 kDa. It is also demonstrated that protein precipitants can be expanded further to polymers with much higher molecular weight than those that are currently in use. Furthermore, the modification of PGA-like polymers by covalent attachments of glucosamine substantially improved their solubility without affecting their crystallization properties. Some preliminary PGA-based screens are presented here.

  20. High-molecular-weight polymers for protein crystallization: poly-γ-glutamic acid-based precipitants

    High-molecular-weight poly-γ-glutamic acid-based polymers have been synthesized, tested and adopted for protein crystallization. Protein crystallization has been revolutionized by the introduction of high-throughput technologies, which have led to a speeding up of the process while simultaneously reducing the amount of protein sample necessary. Nonetheless, the chemistry dimension of protein crystallization has remained relatively undeveloped. Most crystallization screens are based on the same set of precipitants. To address this shortcoming, the development of new protein precipitants based on poly-γ-glutamic acid (PGA) polymers with different molecular-weight ranges is reported here: PGA-LM (low molecular weight) of ∼400 kDa and PGA-HM (high molecular weight) of >1000 kDa. It is also demonstrated that protein precipitants can be expanded further to polymers with much higher molecular weight than those that are currently in use. Furthermore, the modification of PGA-like polymers by covalent attachments of glucosamine substantially improved their solubility without affecting their crystallization properties. Some preliminary PGA-based screens are presented here

  1. Detrital processing in streams exposed to acidic precipitation in the Central Appalachian Mountains

    Continuing high rates of acidic deposition in the eastern United States may lead to long-term effects on stream communities, because sensitive catchments are continuing to lose anions and cations. A two-year study of the effects of pH and associated water chemistry variables on detrital processing in three streams with different bedrock geology in the Monongahela National Forest, West Virginia were investigated. Leaf pack processing rates and macroinvertebrate colonization and microbial biomass (ATP concentration) on the packs in the three stream were compared. It was found that macroinvertebrate and microbial communities differed both among streams that differed in their capacity to buffer the effects of acidic precipitation and among years in the same stream; these differences in biotic communities were not large enough to affect rates of leaf processing between the two years of the study, but they did significantly affect processing rates between acidic and circumneutral streams

  2. Factors affecting the rate of hydrolysis of phenylboronic acid in lab-scale precipitate reactor studies

    Removing aromatic carbon from an aqueous slurry of cesium-137 and other alkali tetraphenylborates by acid hydrolysis will be an important step in preparing high-level radioactive waste for vitrification at the Savannah River Site's Defense Waste Processing Facility (DWPF). Kinetic data obtained in bench-scale precipitate hydrolysis reactors suggest changes in operating parameters to improve product quality in the future plant-scale radioactive operation. The rate-determining step is the removal of the fourth phenyl group, i.e. hydrolysis of phenylboronic acid. Efforts to maximize this rate have established the importance of several factors in the system, including the ratio of copper(II) catalyst to formic acid, the presence of nitrite ion, reactions of diphenylmercury, and the purge gas employed in the system

  3. Factors affecting the rate of hydrolysis of phenylboronic acid in lab-scale precipitate reactor studies

    Bannochie, C.J.; Marek, J.C.; Eibling, R.E.; Baich, M.A.

    1992-10-01

    Removing aromatic carbon from an aqueous slurry of cesium-137 and other alkali tetraphenylborates by acid hydrolysis will be an important step in preparing high-level radioactive waste for vitrification at the Savannah River Site`s Defense Waste Processing Facility (DWPF). Kinetic data obtained in bench-scale precipitate hydrolysis reactors suggest changes in operating parameters to improve product quality in the future plant-scale radioactive operation. The rate-determining step is the removal of the fourth phenyl group, i.e. hydrolysis of phenylboronic acid. Efforts to maximize this rate have established the importance of several factors in the system, including the ratio of copper(II) catalyst to formic acid, the presence of nitrite ion, reactions of diphenylmercury, and the purge gas employed in the system.

  4. Factors affecting the rate of hydrolysis of phenylboronic acid in lab-scale precipitate reactor studies

    Bannochie, C.J.; Marek, J.C.; Eibling, R.E.; Baich, M.A.

    1992-01-01

    Removing aromatic carbon from an aqueous slurry of cesium-137 and other alkali tetraphenylborates by acid hydrolysis will be an important step in preparing high-level radioactive waste for vitrification at the Savannah River Site's Defense Waste Processing Facility (DWPF). Kinetic data obtained in bench-scale precipitate hydrolysis reactors suggest changes in operating parameters to improve product quality in the future plant-scale radioactive operation. The rate-determining step is the removal of the fourth phenyl group, i.e. hydrolysis of phenylboronic acid. Efforts to maximize this rate have established the importance of several factors in the system, including the ratio of copper(II) catalyst to formic acid, the presence of nitrite ion, reactions of diphenylmercury, and the purge gas employed in the system.

  5. Recovery of molybdenum, nickel and cobalt by precipitation from the acidic leachate of a mineral sludge.

    Vemic, M; Bordas, F; Comte, S; Guibaud, G; Lens, P N L; van Hullebusch, E D

    2016-09-01

    The objective of this study was to investigate the recovery potential of molybdenum (Mo), nickel (Ni) and cobalt (Co) from synthetic and real acidic leachate of a mineral sludge from a metal recycling plant by sulfide precipitation. The operational parameters (metal sulfide (M/S) ratio 0.1-1, agitation speed 0-100 rpm, contact time 15-120 min and pH 1-5) were optimized in batch conditions on synthetic metal leachate (0.5 M HNO3, Mo = 101.6 mg L(-1), Ni = 70.8 mg L(-1), Co = 27.1 mg L(-1)) with a 0.1 M Na2S solution. Additionally, recovery of the target metals was theoretically simulated with a chemical equilibrium model (Visual MINTEQ 3.0). The optimized Na2S precipitation of metals from the synthetic leachate resulted in the potential selective recovery of Mo at pH 1 (98% by modeling, 95% experimental), after simultaneous precipitation of Ni and Co as sulfide at pH 4 (100% by modeling, 98% experimental). Metal precipitation from the real leachate (18 M H2SO4, Mo = 10,160 mg L(-1), Ni = 7,080 mg L(-1), Co = 2,710 mg L(-1)) was performed with 1 M Na2S, and resulted in a maximal Mo recovery at pH 2 (50%), while maximal recoveries of Ni and Co were observed at pH 4 (56% and 60%, respectively). Real leachate gave a lower metals recovery efficiency compared with synthetic leachate, which can be attributed to changes in the pH, nature of leachant, co-precipitation of Zn and competition for S(2-) ions. PMID:26824137

  6. Modeling the neutralizing processes of acid precipitation in soils and glacial sediments of northern Ohio

    Eckstein, Yoram; Hau, Joseph A.

    1992-02-01

    Most studies of the acidic deposition phenomena have been focused on processes occurring in the northeastern USA and Scandinavia. In these regions the soil cover is thin, the bedrock is acidic, and the terrain has very poor acid buffering capacity. Most of the US Midwest, including northern Ohio, has been ignored because the terrain is covered by glacial sediments with an abundance of carbonate minerals. Yet, for the last three decades the area has been experiencing acidic precipitation with a pH range of 3.5-4.5. the lowest in the USA. Samples of precipitation, soil water, and shallow ground water from Leroy Township in Lake County, Ohio, and from Wooster Township in Wayne County, Ohio, were analyzed and processed using WATEQ3 and PHREEQE computer models to quantify the effects of the acidic deposition. The two regions are characterized by very similar topographic, geological and hydrogeological conditions. Although the cation content of the precipitation in both regions is similar, the anion concentrations are much higher (sulfate by 70%, nitrate by 14% and chloride by 167%) in Leroy, located 50 km east-northeast and downwind of the Cleveland-Akron industrial complex, than in Wooster, located 80 km south-southwest and off-wind from the industrial complex. Computer modeling results indicate that buffering of acidic deposition in the surficial sediments and glacial tills of the two regions is dominated apparently by calcite dissolution, and dissolution and exchange of hydrogen for magnesium ions are the dominant neutralizing processes. However, reaction simulations also suggest that the buffering capacity of the Leroy soils and tills has been depleted to a much greater degree than in Wooster Township. In Leroy more acidic input is reacting with less buffering material to produce lower soil and groundwater pH. The depletion of carbonate and alumino-silicate minerals in the soils of Leroy Township is occurring at a rate that is 3-5 times faster than in the same type

  7. An assessment of acid fog

    Airborne particles have long been associated with adverse effects on public health, begin with the notorious air pollution disasters of several decades ago. Although H2SO4 was identified early on as a potential causal factors during these episodes (in part because of concern for potential health effects of particle acidity per se has intensified only recently. Most of the recent aerometric research in the US on acid fog has focused on the ability of clouds and fog to deliver acidity to vegetation and ecosystems. Strong acids are characterized chemically by their pH or H+ concentration. For fog, concentrations are referred to the droplet liquid content; for other (i.e., ''clear air'') aerosols, to the volume of air sampled. A useful measure of the relationship between aerosol and fog is obtained by comparing their mass concentrations on the basis of the same volume of air, by multiplying fogwater concentrations by liquid water content (LWC). This paper reviews fog measurement capability, physical properties and chemistry, and presents a simple urban airshed model which is used to simulate the evolution of fog and aerosol concentrations under urban stagnation conditions

  8. Precipitation of pertechnetate ion from nitric acid solutions using complexes of copper(II) with heterocyclic N-donor ligands

    The TcO4- precipitation with organic complexes of Cu(II) from nitric acid solutions was studied. Complex Cu(phen)3(NO3)2 was chosen as the optimal precipitant. The conditions for maximum Tc precipitation of 95 ± 3 % were determined. It was shown the possibility to obtain metal-Tc alloys by thermal treatment of the precipitates. As found, the addition of the fusible metal (Sn) to the sediment was required to receive appropriate matrix. Cu-Tc-Sn matrix was tested for Tc leaching. (author)

  9. Oxidative Precipitation of Manganese from Acid Mine Drainage by Potassium Permanganate

    Regeane M. Freitas; Perilli, Thomaz A. G.; Ladeira, Ana Claudia Q.

    2013-01-01

    Although oxidative precipitation by potassium permanganate is a widely recognised process for manganese removal, research dealing with highly contaminated acid mine drainage (AMD) has yet to be performed. The present study investigated the efficiency of KMnO4 in removing manganese from AMD effluents. Samples of AMD that originated from inactive uranium mine in Brazil were chemically characterised and treated by KMnO4 at pH 3.0, 5.0, and 7.0. Analyses by Raman spectroscopy and geochemical mode...

  10. Chemico-physical processes influencing acidic precipitation: the case study of Milan urban area

    Maffeis, G. [Environmental adviser, Verdello, Bergamo (Italy); Tamponi, M. [National Health Service IV U.O. PMIP, USL 7, Lecco (Italy); Tebaldi, G. [National Health Service IV U.O. PMIP, USL 38, Milan (Italy)

    1996-07-01

    The aim of the model presented in this work is to describe the acidic contents of cloud droplets` temporal evolution, both during their formation process and the following stage of precipitation. The attention is mainly focused on precipitation in which the contribution of local polluted air masses, typical of big urban areas, is predominant. Some phenomena are particularly taken into consideration: the exchange processes of those pollutants mostly influencing the pH, from the gas to the liquid phase; the process of sulphur oxidation in the liquid phase and finally the phenomenon of inclusion of the atmospheric particulate through interception processes. The model has been useful in the analysis of experimental data about the precipitations in Milan urban area from the January 1st 1991 to June 30th 1992. For instance, it has been possible to explain both a rapid decrease of pH, happening with strong convective instability, and the significant washout of basic particulate, taking place during the first minutes in most of the events. The sensitivity analysis has also shown that pH depends on ammonia concentration and on temperature in a significant way.

  11. Assessing the skill of seasonal precipitation and streamflow forecasts in sixteen French catchments

    Crochemore, Louise; Ramos, Maria-Helena; Pappenberger, Florian

    2015-04-01

    Meteorological centres make sustained efforts to provide seasonal forecasts that are increasingly skilful. Streamflow forecasting is one of the many applications than can benefit from these efforts. Seasonal flow forecasts generated using seasonal ensemble precipitation forecasts as input to a hydrological model can help to take anticipatory measures for water supply reservoir operation or drought risk management. The objective of the study is to assess the skill of seasonal precipitation and streamflow forecasts in France. First, we evaluated the skill of ECMWF SYS4 seasonal precipitation forecasts for streamflow forecasting in sixteen French catchments. Daily flow forecasts were produced using raw seasonal precipitation forecasts as input to the GR6J hydrological model. Ensemble forecasts are issued every month with 15 or 51 members according to the month of the year and evaluated for up to 90 days ahead. In a second step, we applied eight variants of bias correction approaches to the precipitation forecasts prior to generating the flow forecasts. The approaches were based on the linear scaling and the distribution mapping methods. The skill of the ensemble forecasts was assessed in accuracy (MAE), reliability (PIT Diagram) and overall performance (CRPS). The results show that, in most catchments, raw seasonal precipitation and streamflow forecasts are more skilful in terms of accuracy and overall performance than a reference prediction based on historic observed precipitation and watershed initial conditions at the time of forecast. Reliability is the only attribute that is not significantly improved. The skill of the forecasts is, in general, improved when applying bias correction. Two bias correction methods showed the best performance for the studied catchments: the simple linear scaling of monthly values and the empirical distribution mapping of daily values. L. Crochemore is funded by the Interreg IVB DROP Project (Benefit of governance in DROught adaPtation).

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

    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.

  13. Acid Rain Examination and Chemical Composition of Atmospheric Precipitation in Tehran, Iran

    Mohsen Saeedi

    2012-01-01

    Full Text Available Air pollution is one of the most important environmental problems in metropolitan cities like Tehran. Rain and snow, as natural events, may dissolve and absorb contaminants of the air and direct them onto the land or surface waters which become polluted. In the present study, precipitation samples were collected from an urbanized area of Tehran. They were analyzed for NO3-, PO43-, SO42-, pH, turbidity, Electrical Conductivity (EC, Cu, Fe, Zn, Pb, Ni, Cr, and Al. We demonstrate that snow samples were often more polluted and had lower pH than those from the rain, possibly as an effect of adsorption capability of snow flakes. Volume weighted average concentrations were calculated and compared with some other studies. Results revealed that Tehran's precipitations are much more polluted than those reported from other metropolitan cities. Cluster analysis revealed that studied parameters such as metals and acidity originated from the same sources, such as fuel combustion in residential and transportation sectors of Tehran.

  14. Electrolysis of oxalic acid in simulative mother liquor generated from plutonium (IV) oxalate precipitation process

    Cyclic voltammetry and linear voltammetry methods were used to study the characteristics of electrochemical behavior of oxalic acid (OA) and plutonium at platinum anode in simulative mother liquor (OW) generated from Pu (IV) oxalate precipitation step. The cyclic voltammograms show that the oxidation of OA on Pt anode is an irreversible reaction. An electrolytic method was described for the destruction of the OA in OW. 0.002-0.1 g/L Pu has no obvious effect on the destruction velocity of OA. Under a constant current density, OA can be destroyed to below 0.001 mol/L after a certain time, which can satisfy the requirements of the technical process. (authors)

  15. Recovery of metals from Cuban nickel tailings by leaching with organic acids followed by precipitation and magnetic separation

    The percolation leaching of the Cuban nickel tailings containing 0.34% Ni, 0.08% Co and 44.2% Fe was investigated by using tartaric and oxalic acids at different concentrations. About 70% Ni, 80% Co and 30% Fe were extracted after 5 days of leaching with the mixture of 0.15 mol/L tartaric acid and 0.05 mol/L oxalic acid at ambient temperature and normal pressure. Nickel and cobalt extraction of 80% as well as iron extraction of 50% were achieved from the pregnant solution by means of precipitation at 80 deg. C for 2 h. The precipitation at ambient temperature led to a similar result after 16 days. Cobalt, nickel and iron oxalates were found in the precipitate by using the X-ray diffraction method. The regeneration of acids during the precipitation step made possible the reuse of the raffinate at the leaching step. Heating of the precipitate at 200 deg. C increased the metal concentration to 1.22% Ni and 0.33% Co, which can be fed in the existing nickel plant in Moa, Cuba. The magnetic processing of the leaching residues led to a non-magnetic product containing less than 20% Fe and a magnetic product containing more than 50% Fe

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

    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.

  17. Benefit-cost implications of acid rain controls: An evaluation of the NAPAP integrated assessment

    Concluding ten years of study, the US National Acid Precipitation Assessment Program (NAPAP) recently issued its integrated assessment report designed to provide guidance to policy makers on the sources and effects of acid deposition, and the costs and benefits of alternative control measures. This paper focuses on an evaluation of the benefit-cost implications of acid rain controls as revealed by two of the five major questions addressed in the NAPAP assessment framework. While the NAPAP effort made significant scientific contributions to the study of acid deposition, key gaps are found in the assessment of benefits and costs most relevant to policy decisions. Lessons learned from NAPAP may be helpful in avoiding similar problems in assessing emerging environmental issues such as global climate change

  18. Benefit-cost implications of acid rain controls: an evaluation of the NAPAP integrated assessment

    Concluding ten years of study, the US National Acid Precipitation Assessment Program (NAPAP) recently issued its integrated assessment report designed to provide guidance to policy makers on the sources and effects of acid deposition, and the costs and benefits of alternative control measures. This paper focuses on an evaluation of the benefit-cost implications of acid rain controls as revealed by two of the five major questions addressed in the NAPAP assessment framework. While the NAPAP effort made significant scientific contributions to the study of acid deposition, key gaps are found in the assessment of benefits and costs most relevant to policy decisions. Lessons learned from NAPAP may be helpful in avoiding similar problems in assessing emerging environmental issues such as global change

  19. On the importance of observational data properties when assessing regional climate model performance of extreme precipitation

    Sunyer Pinya, Maria Antonia; Sørup, Hjalte Jomo Danielsen; Christensen, Ole Bøssing;

    2013-01-01

    In recent years, there has been an increase in the number of climate studies addressing changes in extreme precipitation. A common step in these studies involves the assessment of the climate model performance. This is often measured by comparing climate model output with observational data. In the...... majority of such studies the characteristics and uncertainties of the observational data are neglected. This study addresses the influence of using different observational datasets to assess the climate model performance. Four different datasets covering Denmark using different gauge systems and comprising...... datasets, the RCMs are ranked according to their performance using two different metrics. These are based on the error in representing the indices and the spatial correlation. In comparison to the mean, extreme precipitation indices are highly dependent on the spatial resolution of the observations. The...

  20. Study on complex formation of cadmium(II) ions, 8. Identification of the precipitates formed in the solutions containing cadmium(II) ion and amino acid

    Matsui, Haruo; Hirabayashi, Yoshihiro (Government Industrial Research Inst., Nagoya (Japan))

    1984-02-01

    In the potentiometric titration of the solution containing a cadmium(II) ion and an amino acid, white precipitates often appear in the test solution, and they disturb the emf measurements. Such precipitates were formed in the solutions, pH ranging 7.5--8.5, during the course of titrations of the test solutions containing cadmium(II) ion and amino acid such as glycine, ..cap alpha..-alanine. 2-aminobutanoic acid, 3-aminobutanoic acid, 4-aminobutanoic acid, 2-aminopentanoic acid, 5-aminopentanoic acid, 2-aminohexanoic acid, 6-aminohexanoic acid, aspartic acid, glutamic acid, asparagine, or glutamine. The identification of the precipitates obtained from the solutions containing cadmium(II) ion and L-aspartic acid, 4-aminobutanoic acid, or 6-aminohexanoic acid were carried out by elemental analysis and infrared spectroscopy. These results indicated that the precipitate obtained from the solution containing cadmium(II) ion and L-aspartic acid was 1:1 cadmium(II)-L-aspartic acid complex and did not contain any cadmium(II) hydroxide, and other two precipitates were mostly cadmium(II) hydroxide and contained a little cadmium(II)-amino acid complexes.

  1. Assessing surface water consumption using remotely-sensed groundwater, evapotranspiration, and precipitation

    Anderson, Ray G.; Lo, Min-Hui; Famiglietti, James S.

    2012-01-01

    Estimates of consumptive use of surface water by agriculture are vital for assessing food security, managing water rights, and evaluating anthropogenic impacts on regional hydrology. However, reliable, current, and public data on consumptive use can be difficult to obtain, particularly in international and less developed basins. We combine remotely-sensed precipitation and satellite observations of evapotranspiration and groundwater depletion to estimate surface water consumption by irrigated...

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

    Miura, Chitose; Matsunaga, Hisami; Haginaka, Jun

    2016-08-01

    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. PMID:26776340

  3. Chemical Evolution of Acid Precipitation in Unsaturated Zone of the Pennsylvanian Siltstones and Shales of Central Ohio

    The North Appalachian Experimental Watershed in Coshocton, Ohio has recorded over a 30-yr period average pH of precipitation of 4.7. The area lies within the Pennsylvanian siltstones and shale dominated by aluminosilicates and evolution of acid dep...

  4. Experimental studies of boric acid precipitation in nuclear power plants during the post-LOCA long-term cooling period

    Boric acid precipitation, which recently was considered as a generic safety issue by NRC, could happen in the pressurized water reactor during the post-LOCA long-term cooling period. Chemical additives and containments debris mix together with boric acid in the sump pool, then generating new insoluble chemical products and reducing boric acid solubility. This study is to provide the experimental data base and theoretical method for the boric acid solubility in the mixture solution, and develop screening process to select key containment debris for in-depth study. Low temperature experiments for boric acid solubility in NaOH and TSP mixture solution were performed, and the physical model was proposed to predict the boric acid solubility under various temperatures and fractions of NaOH and TSP. Boric acid solubility stably and obviously increases in the mixture solution as temperature and the fractions of NaOH and TSP increase. Importance Factor (F) for the screening process is obtained in order to reflect the total effects of the dissolution, transport, chemical and physical influence of debris on precipitation. Through the screening process, aluminum, concrete, NuKon fiberglass, calcium silicate, and epoxy were selected out as key debris for further study. Dissolvability tests of concrete, calcium silicate and aluminum were performed to investigate their dissolution characteristics. The sensitivity study on pH, temperature, buffer agents and geometry for precipitation was discussed. AlOOH, Na3AlSi3O8 and Ca3(PO4)2 were recommended as the most possible precipitates and their solubility was investigated

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

    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.

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

    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.

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

    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.

  8. Tartaric acid-assisted co-precipitation synthesis of Er3+-doped Lu2O3 nanopowders

    Neng Li Wang; Xi Yan Zhang; Peng He Wang

    2012-01-01

    Erbium-doped lutetia nanopowders were synthesized by a novel co-precipitation method using tartaric acid as precipitant.The properties of the samples were investigated by Fourier transform infrared spectroscopy (FTIR),X-ray diffraction (XRD),TG-DSC,field emission scanning electron microscopy (FE-SEM),and upeonversion luminescence analysis.Pure cubic Lu2O3 nanopowders were directly obtained when the precursor was calcined at 800 ℃ for 2 h,the samples showed strong upconversion luminescence under excitation of 980 nm laser diode.

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

    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

  10. Assessment of Acid Deposition Effects on Water Quality of the Upper Rio Grande River Section in Texas

    John L. Gossage; Kaiming Yan; Qi Fu; Badri Parajuli; Qin Qian; Thomas Ho

    2013-01-01

    Airborne pollutants such as SO42- and NO3- that cause acid rain may pollute water resources via acid deposition. However, such effects on the water quality of the upper Rio Grande River section in Texas have not been systematically studied. The objective of this study is to collect and analyze field data, and perform hydrological and water chemistry analyses to assess acid deposition effects on the river water quality. The analysis of the precipitation data indicates that the concentrations ...

  11. Comparison of inhibitory activity on calcium phosphate precipitation by acidic proline-rich proteins, statherin, and histatin-1.

    Tamaki, N; Tada, T; Morita, M; Watanabe, T

    2002-07-01

    This study quantitatively compares the inhibition of calcium phosphate (CaP) precipitation by the salivary acidic proline-rich proteins (PRPs) statherin and histatin-1. Saliva and CaCl2 in 125 mM imidazole buffer (pH 7.0) were incubated with potassium phosphate and a hydroxyapatite (HAP) suspension, for 30 min at 25 degrees C, then filtered through nitrocellulose. The calcium (Ca) concentration in the filtrate was measured by atomic absorption spectrophotometry, then deducted from that in the initial solution to determine the amount of CaP precipitation after 30 min. The values of the inhibitory activities on CaP precipitation relative to crude parotid saliva were 4.7, 4.9, 6.9, and 65.8 for histatin-1, large PRPs, small PRPs, and statherin, respectively. PMID:12060866

  12. Interface-coupled dissolution-precipitation processes during acidic weathering of multicomponent minerals

    Ruiz-Agudo, Encarnacion; King, Helen E.; Patiño-López, Luis D.; Putnis, Christine V.; Geisler, Thorsten; Rodriguez-Navarro, Carlos M.; Putnis, Andrew

    2015-04-01

    The chemical weathering of carbonate and silicate minerals on the Earth's surface controls important geochemical processes such as erosion rates and soil formation, ore genesis or climate evolution. The dissolution of most of these minerals is typically incongruent, and results in the formation of surface coatings (altered layers, also known as leached layers). These coatings may significantly affect mineral dissolution rates over geological timescales, and therefore a great deal of research has been conducted on them. However, the mechanism of leached layer formation is a matter of vigorous debate. Here we report on an in situ atomic force microscopy (AFM) and real-time Mach-Zehnder phase-shift interferometry (PSI) study of the dissolution of wollastonite, CaSiO3, and dolomite, CaMg(CO3)2, as an example of surface coating formation during acidic weathering of multicomponent minerals. Our in situ results provide clear direct experimental evidence that leached layers are formed in a tight interface-coupled two-step process: stoichiometric dissolution of the pristine mineral surfaces and subsequent precipitation of a secondary phase (silica in the case of wollastonite, or hydrated magnesium carbonate in the case of dolomite) from a supersaturated boundary layer of fluid in contact with the mineral surface. This occurs despite the bulk solution remaining undersaturated with respect to the secondary phase. The validation of such a mechanism given by the results reported here completely changes the conceptual framework concerning the mechanism of chemical weathering, and differs significantly from the concept of preferential leaching of cations postulated by most currently accepted incongruent dissolution models.

  13. The effects of acid precipitation runoff episodes on reservoir and tapwater quality in an Appalachian Mountain water supply.

    Sharpe, W E; DeWalle, D R

    1990-01-01

    The aluminum concentration and Ryznar Index increased and the pH decreased in a small Appalachian water supply reservoir following acid precipitation runoff episodes. Concomitant increases in tapwater aluminum and decreases in tapwater pH were also observed at two homes in the water distribution system. Lead concentrations in the tapwater of one home frequently exceeded recommended levels, although spatial and temporal variation in tapwater copper and lead concentrations was considerable. Sin...

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

    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 H2 SO4 of alkaline aqueous solutions containing vanadium pentoxide (V2 O5) at 60 ± 2 deg C. 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 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%. (author)

  15. Study of molybdenum (VI) complexation and precipitation by zirconium (IV) in strongly acid medium. Application to nuclear spent fuel dissolution

    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 95Mo 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 ZrMo2O7(OH)2,2H2O. 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)

  16. Acidic weathering of carbonate building stones: experimental assessment

    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.

  17. Assessing IPCC AR4 Coupled Model Simulations of Late-20th Century Winter Precipitation Over North America

    McAfee, S. A.; Russell, J. L.

    2008-12-01

    Consistent with a southward bias in zonal winds in eighteen of the Intergovernmental Panel on Climate Change Fourth Assessment (IPCC AR4) simulations of the 20th century, model estimates of stormtrack location tend to cluster south of the observed stormtrack, particularly during March and April. There are two mechanisms by which a southward-displaced stormtrack could increase downstream precipitation. The first is by changing the latitudinal distribution of storms. Second, a southward-displaced stormtrack allows storms to develop over warmer sea surfaces, increasing the amount of water they hold. Although they capture the general structure and seasonality of precipitation over North America quite well, IPCC AR4 coupled model simulations of the late-20th century (1979-1999) typically overestimate winter (November to April) precipitation in western North America in comparison to values from the Global Precipitation Climatology Project version 2 (GPCPv2). While there are multiple controls on precipitation amount and distribution, we suspect that a southward bias in zonal wind speeds contributes to the precipitation bias observed in many of the models included in this study. Many of the models in this study show greater overestimates of precipitation to the south than to the north, consistent with a southward bias in stormtrack position. The generally positive bias in precipitation across western North America seen in many of the models suggests that sea-surface temperature may also play a role. As the modeling community moves toward coupled earth system models with dynamic vegetation, the precipitation bias may become a more significant problem. Vegetation types are typically determined by seasonal patterns in temperature and precipitation. Errors of even 25% in precipitation totals may contribute to significant changes in the simulated vegetation and carbon fluxes, particularly in arid and semi-arid regions like the western United States.

  18. Uncertainty assessment through a precipitation dependent HUP: an application to a small Southern Italy catchment

    Biondi, D.; Versace, P.; Sirangelo, B.

    2009-04-01

    The present study focuses on the application of a precipitation dependent HUP (Hydrologic Uncertainty Processor) to assess the predictive uncertainty on water discharge predictions for a small headwater catchment located in Calabria (South Italy) through a complete example of the estimation procedure, modelling assumptions and results. The applied HUP was proposed by Krzysztofowicz in 1999, and is a component of the Bayesian forecasting system (BFS) which provides a general methodology for probabilistic forecasting via any deterministic hydrologic model. Within the BFS framework, the task of the HUP is to quantify the effects of various uncertainty sources on the forecasts, e.g. of river discharges, under the hypothesis that there is no precipitation uncertainty. According to the principle of Bayesian revision of a probability distribution, the general formulation of the HUP supplies the hydrologic uncertainty in terms of a family,g°(×|s,h0), of posterior densities of discharge H, for every possible realization s of the model river discharge process S and observation H0 = h0 of river discharge up to the forecast time. This result is obtained through the revision of a prior distribution g of the predictand, which exists before the preparation of a forecast, on the basis of a likelihood function f estimated from past evidence on model performance against observations. The implemented HUP rests on the following assumptions: precipitation dependent structure; nonstationarity of both actual river stage and model river stage process with lead time n; meta-gaussian formulation for all the conditional distributions. The study watershed is the test site of the Turbolo Creek catchment (29 km2), a tributary of the Crati River, located in Southern Italy. The hydro-meteorological database used within this study comprises rainfall, temperature, and discharge values sampled with a 20 minutes temporal resolution. The hydrologic response in the HUP is simulated by the RISE

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

    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.

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

    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. The Global Network of Isotopes in Precipitation after 55 years: assessing past, present and future developments

    Terzer, Stefan; Araguas-Araguas, Luis; Wassenaar, Leonard I.; Aggarwal, Pradeep K.

    2015-04-01

    The Global Network of Isotopes in Precipitation (GNIP) is a global observation programme operated by the International Atomic Energy Agency (IAEA), in cooperation with the World Meteorological Organization (WMO) and more than 100 contributing institutions worldwide. GNIP has been the primary repository for baseline stable (δ18O, δ2H) and radioactive (3H) isotope data since its foundation in 1960. The impetus for GNIP was the monitoring of radioactive fallout from atmospheric thermonuclear testing and resulting tritium levels of precipitation, but tritium together with stable isotopes was recognized as a key to understanding hydrological processes. Later, new applications were developed focusing on hydrometeorology and paleoclimatic research. Increasingly, GNIP data are being used more widely in ecological and forensic investigations, e.g. for tracking of migratory animals. The GNIP database comprises more than 135,000 isotopic records (δ18O: 63,000; δ2H: 55,000; 3H: 63,000) of monthly composite precipitation samples from more than 1,000 stations worldwide. About 300 stations are currently active for stable isotopes and ca. 100 for tritium. Data for most of the active stations is available up to 2013. Several national isotopic observation networks (e.g. in Austria, Australia, China or the United States of America) exist besides GNIP, complementing precipitation isotope data at national levels. The spatially and temporally discrete nature of the GNIP dataset induces coverage gaps. Recently, highly-resolved gridded datasets were established to help overcome this deficiency through geostatistical prediction models. These 'isoscape' (isotopic landscapes) are based on combinations of multiple regression and interpolation methods, with a range of parameterization available at regional and global levels. Attempts to bridge the gap between 'one-size-fits-all' global parameterization and improved predictions at regional and local levels led to the establishment of a

  2. Potassium salts of fatty acids as precipitating agents of alkaline earth metal ions

    Regularities have been studied of precipitation of ions of alkaline-earth elements with caprilate, pelargonate, caprinate, undecanate, laurate, tridecanate, myristate, pentadecanate, palmitate, and stearate of potassium. It has been shown that completeness of precipitation of metal ions is determined by the nature of alkaline-earth metal and potassium salt as well as by pH value and temperature of the solution. The study of temperature dependence of soaps of alkaline-earth metals makes it possible to calculate the heats of dissolution of laurates of alkaline-earth metals, and a change in entropy and free energy

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

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

    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 ...

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

    Martins A. H.

    2000-01-01

    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 %.

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

    Majchrowicz, Magdalena E.; Brilman, D.W.F. (Wim); Groeneveld, Michiel 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

  6. Long-term patterns in dissolved organic carbon in boreal lakes: the role of incident radiation, precipitation, air temperature, southern oscillation and acid deposition

    J. J. Hudson

    2003-01-01

    Full Text Available Both lake-specific (e.g. pH and regional (e.g. precipitation factors affect DOC concentration and pattern. Using annual DOC concentration in nine boreal lakes in the ice-free season, the potential influences of five regional factors, air temperature, precipitation, SO4 deposition, solar radiation (photosynthetically active radiation, or PAR and the southern oscillation index (SOI have been explored through multiple regression. Mean solar radiation, winter precipitation and summer precipitation explained 59% of the variation in the mean DOC concentration (F3,17= 8.29, p= 0.0013. Solar radiation and winter precipitation were correlated, negatively, while summer precipitation was correlated, positively, with DOC concentration. Because these relationships were based on only 21 years of data (1978 to 1998, the significance of the parameters in the regression model was evaluated with a randomisation test. This re-analysis indicated that summer precipitation did not contribute significantly to the regression model ( prand= 0.183. The final multiple regression explained 50% of the variation in DOC (F2,18 = 9.33, prand= 0.002 based on solar radiation and winter precipitation. These results suggest that solar radiation and winter precipitation have a significant role in determining long-term DOC concentration in boreal lakes. Keywords: dissolved-organic-carbon, lakes, climate, solar-radiation, precipitation, acid-precipitation, Precambrian-Shield-Ontario

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

    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.

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

    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.

  9. A PRELIMINARY INVESTIGATION INTO THE USE OF ACID-TOLERANT PRECIPITATED CALCIUM CARBONATE FILLERS IN PAPERMAKING OF DEINKED PULP DERIVED FROM RECYCLED NEWSPAPER

    Jing Shen

    2009-08-01

    Full Text Available The use of acid-tolerant precipitated calcium carbonate fillers, including phosphoric acid/sodium hexametaphosphate modified precipitated CaCO3 filler, and sodium silicate/phosphoric acid/sodium hexametaphos-phate modified precipitated CaCO3 filler in papermaking of deinked pulp derived from recycled newspaper was explored. These two acid-tolerant fillers provided considerably more brightness improvement in papers in comparison the unmodified filler, presumably indicating alleviated pulp darkening achieved as a result of better acid-resistant properties. The addition of acid-tolerant fillers into the furnish slurries gave lower system pH as compared with unmodified filler. Among the three fillers used in this work, the effect on retention of modification of the filler with sodium silicate/phosphoric acid/sodium hexametaphosphate was probably the best, as evaluated from ash content measurements. For air permeability of the paper, the use of acid-tolerant fillers provided slightly more improvement in comparison to the unmodified filler. For tensile and burst strength of the paper, the use of sodium silicate/phosphoric acid/sodium hexameta-phosphate modified precipitated calcium carbonate filler gave better results as compared with the other two fillers. Additionally, the improving effect of acid-tolerant fillers on furnish static drainage was found to be slightly weaker than that of unmodified filler.

  10. Decontamination of acid waste water from uranium mining by chemical precipitation

    The aim of the required cleaning process is to reduce the hardness lowering of the SO4 and Fe concentrations, raising the pH value to about 6.5 to 9.0 with simultaneous reduction of the uranium content. Complete precipitation reactions occur, which are affected by composition of the untreated water, changes in the untreated water by storage, chemical dosing etc., so that one specific consumption cannot be stated. The consumption of lime depends on the pH value, the Fe and Mg content of the solution. Other means of precipitation than lime are not suitable, partly for technological reasons and partly from the economic point of view. (orig./HP)

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

    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.

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

    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. PMID:26037163

  13. Studies on the liquid-liquid extraction and ion and precipitate flotation of Co(II) with decanoic acid

    The liquid-liquid extraction, ion and precipitate flotation of Co(II) from chloride media of 1*10-4 M initial Co(II) concentration and μ = 0.1 have been investigated using decanoic acid and the results are compared. Organic solvents used were chloroform in the case of liquid-liquid extraction and ethanol (used as a solvent for the collector and a frother) in the case of flotation. From the results it appears that liquid-liquid extraction takes place through the formation of the complex: (CoR2)2(HR)2 but flotation occurs through the formation of a surface active product which has the empirical formula CoR2. The effects of pH and of decanoic acid concentration on the three separation processes were also investigated and the results discussed. Good agreement was observed between the experimental precipitate flotation curves and the theoretical curve calculated from the data published for Co(II) hydrolysis. (author) 30 refs.; 4 figs.; 1 tab

  14. Assessment of precipitate formation on interaction of irrigants used in different combinations: An in vitro study

    Amarnath Shenoy; Nagesh Bolla; Sayish; Raj K Sarath; C H Sunil Ram; Sumlatha

    2013-01-01

    Introduction: Irrigants play an essential role in the successful debridement and disinfection of pulp space. Various combination of irrigants used during root canal treatment enhance their efficacy, but some form precipitates which affects the diffusion of intracanal medicaments and the seal of the obturated root canal. Aim: To evaluate the combination of various irrigants whether it forms the precipitate and also to quantify the amount of precipitate formed. Materials and Methods: Fi...

  15. 6th Amino Acid Assessment Workshop

    The focus of the 6th workshop is on lysine, arginine, and related amino acids. Functions, metabolic pathways, clinical uses, and upper tolerance intakes are emphasized in the articles that follow. Lysine is arguably the most deficient amino acid in the food supply of countries where poverty exists, ...

  16. Augmenting acid with affective details to assess credibility

    Roland Fleck; Amber Hines; Cheryl Hiscock-Anisman; Kevin Colwell; Ryan Ansarra; Lindsey Cole; Delyana Belarde

    2011-01-01

    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 thef...

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

    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.

  18. The precipitation of radioactive radium-226 from acidic chloride leach liquors with barium chloride

    The conventional barium chloride (BaClsub(2)) precipitation has been effective in the 99+ percent removal of radium-226 as radium-barium sulphate [RaBa(SOsub(4))sub(2)] sludge, from HCl liquors produced by laboratory and pilot leaches of Canadian uranium ores. Radium-226, due to its low-level radiation characteristics, is removed as it has been identified as an environmental and long-term health problem. The formation of the RaBa(SOsub(4))sub(2) sludge was aided due to adequate sulphate (SOsub(4)) concentrations in the HCl pilot liquors produced. Recyclable Rasup(226) concentrations of about 66 pCi/L, in treated effluents, will cost about 1/10 that of effluents below federal environmental guidelines of 10 pCi Rasup(226)/L. Toxic barium (Ba) will potentially build up in effluents as recyclable Rasup(226) concentrations around 66 pCi/L. Barium, in addition to being added to liquors as BaClsub(2) precipitant, is present in the radioactive ore and HCl leach liquors

  19. Acid rain in Australia: a national assessment

    This report reviews the work conducted on acid rain in Australia and identify the major emitters of acid rain precursors on a regional and point source basis. It also highlights the geographical regions most susceptible to acidification and finally identify techniques for minimising acid precursor emissions. Although only a small number of extensive monitoring programs on acid deposition have been carried out in Australia, the evidence to date indicates that acid rain is not a national problem. A number of regions however may warrant careful investigation. In particular, the Kalgoorlie region in Western Australia and Mt. Isa in Queensland which by 1990 will have a combined sulfur dioxide emission of 1300 kilotonnes/annum - approximately 85% of the total anthropogenic Australian emission value for 1985. In view of the quality of existing data on rain acidity in the Latrobe Valley, the projected increase in sulfur dioxide emission from coal-fired power stations by the year 2005, and the acid susceptibility of alpine humus soils in national parks to the north and south of the Valley, new studies are recommended for this region. Other regions that are susceptible to soil acidification include the eastern parts of the Dividing Range in north Queensland and sections of the Kakadu National Park in the Northern Territory. 55 refs., 1 tab, 3 figs

  20. Effects of acid precipitation on a boreal forest ecosystem. Ion budgets and changes in water chemistry for the Laflamme Lake watershed

    Papineau, M.

    1987-01-01

    Data on surface waters have been gathered at the Laflamme Lake Watershed in Quebec as part of an ion budget research program. This watershed was set up in 1980 to assess the effects of long range transport of airborne pollutants on a boreal forest ecosystem receiving moderate to high sulphate loading. Precipitation data indicates that between 1981 and 1984, the average pH of water falling onto the watershed was 4.4, that precipitation quality is cyclic and that loading is episodic. The main components of precipitation on an equivalent basis are sulfate, hydrogen, nitrate and ammonium ions. ALthough the sulphate to nitrate ration is 2:1 on a yearly basis, nitrate ions are more important than sulphates in January. Since water and pollutants build up in the snowpack, spring melt is a critical period during which concentrations in surface waters and exports from the watershed are modifed for many parameters especially hydrogen and bicarbonate ions. Lake water quality is characteristic of lakes that are very sensitive to acidification. High sulfate values seem to indicate that the watershed has been affected by atmospheric loading. The average pH of the lake (6.4) indicates that the lake is not yet greatly acidified. Important buffering occurs in the soil and surficial deposits of the watershed. Stream water is slightly less mineralized, slightly more acidic and shows more pronounced changes in water quality than lake water. Over the last five years, sulfate, conductivity and some heavy metal levels have increased in surface waters while no significant trends were seen for pH and alkalinity. In other Quebec monitoring lakes, trends of decreasing pH were seen during this period. When wet loading is compared to stream output, hydrogen and nitrate ions are seen to be retained in the watershed while Ca, Mg, Na, K, sulphate and chloride are lost. 63 refs. 31 figs. 32 tabs.

  1. Assessing changes in precipitation and temperature over the Iberian Peninsula during the 21st century

    Bernardino, Mariana; Pimpão Silva, Álvaro; Espírito Santo, Fátima; Pinto, Armando

    2016-04-01

    Climate is a major factor driving the spatio-temporal distribution of most ecological systems and human activities, due to their vulnerability to inter-annual climate variability and to climate change. These systems are very sensitive to changes in traditional patterns of regional climate but also to the frequency and magnitude of extreme events. Changes in surface air temperature extremes and precipitation over the Iberian Peninsula were investigated using one of the high resolution climate simulations produced by the Euro-Cordex consortium. Two sets of simulations forced with the new IPCC AR5 emission scenarios RCP4.5 and RCP8.5, with a horizontal resolution of 12.5 km were used to compute climate indices defined by the European Climate Assessment (ECA) project, for present (1970-2010) and for the 21st century climates. Changes in magnitude and in the spatial patterns of these indices were evaluated and once the expected impacts in different sectors are related with these changes, the results provide information to be used in sectoral adaption measures, namely in tourism, water, agriculture, human health, energy and infrastructures.

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

    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.

  3. Global Forty-Years Validation of Seasonal Precipitation Forecasts: Assessing El Ni\\~no-Driven Skill

    Manzanas, R; Cofiño, A S; Gutiérrez, J M

    2013-01-01

    The skill of seasonal precipitation forecasts is assessed worldwide -grid point by grid point- for the forty-years period 1961-2000. To this aim, the ENSEMBLES multi-model hindcast is considered. Although predictability varies with region, season and lead-time, results indicate that 1) significant skill is mainly located in the tropics -20 to 40% of the total land areas-, 2) overall, SON (MAM) is the most (less) skillful season and 3) predictability does not decrease noticeably from one to four months lead-time -this is so especially in northern south America and the Malay archipelago, which seem to be the most skillful regions of the world-. An analysis of teleconnections revealed that most of the skillful zones exhibit significant teleconnections with El Ni\\~no. Furthermore, models are shown to reproduce similar teleconnection patterns to those observed, especially in SON -with spatial correlations of around 0.6 in the tropics-. Moreover, these correlations are systematically higher for the skillful areas. ...

  4. Synthesis of WO3 nanoparticles by citric acid-assisted precipitation and evaluation of their photocatalytic properties

    Graphical abstract: Display Omitted Highlights: ► WO3 nanoparticles were synthesized by a simple citric acid-assisted precipitation. ► WO3 photocatalyst was able to the partial mineralization of rhB, IC and MO. ► WO3 can be considered as a photocatalyst active under visible light irradiation. -- Abstract: WO3 nanoparticles were synthesized by citric acid-assisted precipitation method using a 1:1.5 molar ratio of ammonium paratungstate hydrate (H42N10O42W12·xH2O):citric acid (C6H8O7). The formation of monoclinic crystal structure of WO3 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 WO3, the morphology of the nanoparticles formed was characterized by rectangular and ovoid shapes. The photocatalytic activity of WO3 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 WO3 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.

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

    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

  6. Assessment of different models to describe wax precipitation in flow assurance problems

    Martos, C.; Coto, B.; Espada, J.J.; Robustillo, M.D. [Rey Juan Carlos Univ., Madrid (Spain). Dept. of Chemical and Environmental Technology; Pena, J.L. [Repsol-YPF, Madrid (Spain). Alfonso Cortina Technology Centre

    2008-07-01

    Paraffinic waxes found in crude oils cause flow assurance problems because these compounds can precipitate when temperature decreases during oil production, transport through pipelines or storage. The key variables involved in the wax precipitation process are the wax appearance temperature (WAT) and the wax precipitation curve (WPC). A good understanding of the liquid-solid equilibrium is required in order to model the precipitation process. However, new experimental data is needed to address this issue, particularly the composition of the raw crude oil, the amount of precipitated waxes against temperature and the nature of such waxes. Most models available in the literature require the knowledge of the n-paraffin distribution of crude oil. This type of determination can be carried out using different chromatographic techniques. In this study, experimental WAT and WPC were determined by means of a recently developed multistage fractional precipitation procedure. The trapped crude oil of the precipitated mixtures at each temperature was determined by the 1H NMR technique to determine the true amount of wax precipitated at each temperature. The n-paraffin distribution for the chosen crude oils was determined by chromatographic techniques. The predictive capabilities of the available models was verified by comparing experimental and predicted results. 3 refs.

  7. An independent assessment of the monthly PRISM gridded precipitation product in central Oklahoma

    The development of climate-informed decision support tools for agricultural management requires long-duration location-specific climatologies due to the extreme spatiotemporal variability of precipitation. The traditional source of precipitation data (rain gauges) are too sparsely located to fill t...

  8. Determination of elemental impurities in phosphoric acid by INAA employing a novel method of phosphate precipitation

    Kameník, Jan; Amsil, H.; Kučera, Jan

    2014-01-01

    Roč. 2014, AUG (2014), s. 3455. ISSN 1588-2780 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : instrumental neutron activation analysis * phosphoric acid * elemental impurities * isothermal distillation Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  9. Determination of elemental impurities in phosphoric acid by INAA employing a novel method of phosphate precipitation

    Kameník, Jan; Amsil, H.; Kučera, Jan

    2015-01-01

    Roč. 304, APR (2015), s. 157-162. ISSN 0236-5731 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk LM2011019 Institutional support: RVO:61389005 Keywords : instrumental neutron activation analysis * phosphoric acid * elemental impurities * isothermal distillation Subject RIV: CB - Analytical Chemistry , Separation Impact factor: 1.034, year: 2014

  10. Metal and acidity fluxes controlled by precipitation/dissolution cycles of sulfate salts in an anthropogenic mine aquifer

    Cánovas, C. R.; Macías, F.; Pérez-López, R.

    2016-05-01

    Underground mine drainages are extremely difficult to study due to the lack of information about the flow path and source proximity in relation to the outflow adit. Geochemical processes controlling metals and acidity fluxes in a complex anthropogenic mine aquifer in SW Spain during the dry and rainy season were investigated by geochemical and statistical tools. High concentrations of acidity, sulfate, metals and metalloids (e.g. Fe, Cu, Zn, As, Cd, Ni, Co) were observed due to intense sulfide oxidation processes. The high residence time inside the anthropogenic aquifer, around 40 days, caused the release of significant quantities of metals linked to host rocks (e.g. Al, Ca, Ge, Li, Mg, REE). The most outstanding characteristic of the acid mine drainage (AMD) outflows is the existence of higher Fe/SO4 molar ratios than those theoretical of pyrite (0.50) during most of the monitored period, due to a fire which occurred in 1949 and remained active for decades. Permanent and temporal retention mechanisms of acidity and metals were observed in the galleries. Once released from sulfide oxidation, Pb and As are sorbed on Fe oxyhydroxysulfate or precipitated as low solubility minerals (i.e. anglesite) inside the galleries. The precipitation of evaporitic sulfate salts during the dry season and the subsequent re-dissolution after rainfall control the fluxes of acidity and main metals (i.e. Fe, Mg, Al) from this anthropogenic aquifer. Some elements, such as Cd, Cu, Ni, REE and Zn, are retained in highly soluble sulfate salts while other elements, such as Ge, Pb and Sc, have a lower response to washout processes due to its incorporation in less soluble sulfate salts. In this way, metal concentration during the washout processes would be controlled by the proportion and solubility of each type of evaporitic sulfate salt stored during the dry season. The recovery of metals of economic interest contained in the AMD could help to self-finance the remediation of these waters in

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

    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...

  12. Precipitation data in a mountainous catchment in Honduras: quality assessment and spatiotemporal characteristics

    Westerberg, I.; Walther, A.; Guerrero, J.-L.; Coello, Z.; Halldin, S.; Xu, C.-Y.; Chen, D.; Lundin, L.-C.

    2010-08-01

    An accurate description of temporal and spatial precipitation variability in Central America is important for local farming, water supply and flood management. Data quality problems and lack of consistent precipitation data impede hydrometeorological analysis in the 7,500 km2 Choluteca River basin in central Honduras, encompassing the capital Tegucigalpa. We used precipitation data from 60 daily and 13 monthly stations in 1913-2006 from five local authorities and NOAA's Global Historical Climatology Network. Quality control routines were developed to tackle the specific data quality problems. The quality-controlled data were characterised spatially and temporally, and compared with regional and larger-scale studies. Two gap-filling methods for daily data and three interpolation methods for monthly and mean annual precipitation were compared. The coefficient-of-correlation-weighting method provided the best results for gap-filling and the universal kriging method for spatial interpolation. In-homogeneity in the time series was the main quality problem, and 22% of the daily precipitation data were too poor to be used. Spatial autocorrelation for monthly precipitation was low during the dry season, and correlation increased markedly when data were temporally aggregated from a daily time scale to 4-5 days. The analysis manifested the high spatial and temporal variability caused by the diverse precipitation-generating mechanisms and the need for an improved monitoring network.

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

    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. PMID:27347795

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

    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.

  15. Application of the Nutrient Cycling Model NuCM to a Forest Monitoring Site Exposed to Acidic Precipitation in China

    ZHU Jian-Hua; YU Peng-Tao; T. A. SOGN; WANG Yan-Hui; J.MULDER

    2008-01-01

    The nutrient cycling model NuCM is one of the most detailed models for simulating processes that influence nutrient cycling in forest ecosystems. A field study was conducted at Tieshanping, a Masson pine (Pinus massoniana Lamb.) forest site, in hongqing, China, to monitor the impacts of acidic precipitation on nutrient cycling. NuCM simulations were compared with observed data from the study site. The model produced an approximate fit with the observed data. It simulated the mean annual soil solution concentrations in the two simulation years, whereas it sometimes failed to reproduce seasonal variation. Even though some of the parameters required by modcl running were measured in the field,some others were still highly uncertain and the uncertainties were analyzed. Some of the uncertain parameters necessary for model running should be measured and calibrated to produce a better fit between modeled results and field data.

  16. Effect of Surface Precipitate on the Crevice Corrosion in HYBRID and Oxalic Acid Solution

    Park, S. Y.; Jung, J. Y.; Won, H. J.; Kim, S. B.; Choi, W. K.; Moon, J. K. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, S. J. [Chungnam National Univ., Daejeon (Korea, Republic of)

    2015-05-15

    In this study, we investigated the characteristics of the crevice corrosion for Inconel-600 and 304SS in OA solution according to the change in pH. The evaluation of the crevice corrosion with the chemical thermodynamic analysis identified the effect of the residual chemicals such as iron-oxalate and nickeloxalate to the crevice corrosion behavior. Test results were compared with those of HYBRID (HYdrizine Base Reductive metal Ion Decontamination). The crevice corrosion properties of 304 SS and Inconel-600 in HYBRID and oxalic acid solution were evaluated. In case of oxalic acid solution, the corrosion rate on 304SS was rapidly increased with a pH decrease of around 2, but there was no increase in the corrosion rate on Inconel-600.

  17. Effect of Surface Precipitate on the Crevice Corrosion in HYBRID and Oxalic Acid Solution

    In this study, we investigated the characteristics of the crevice corrosion for Inconel-600 and 304SS in OA solution according to the change in pH. The evaluation of the crevice corrosion with the chemical thermodynamic analysis identified the effect of the residual chemicals such as iron-oxalate and nickeloxalate to the crevice corrosion behavior. Test results were compared with those of HYBRID (HYdrizine Base Reductive metal Ion Decontamination). The crevice corrosion properties of 304 SS and Inconel-600 in HYBRID and oxalic acid solution were evaluated. In case of oxalic acid solution, the corrosion rate on 304SS was rapidly increased with a pH decrease of around 2, but there was no increase in the corrosion rate on Inconel-600

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

    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.

  19. Thermodynamic Assessment of Silica Precipitation in the Primary Coolant of PWR Plants

    Increasing silica concentration has been observed in many plants' reactor coolant system (RCS) following a refueling outage as a result of the cross contamination between the refueling cavity and the spent fuel pool. To have a better understanding of the role of silica on the fuel crud deposition, MULTEQ (MULTiple Equilibrium) calculations were performed in this study to predict high-temperature aqueous and precipitated species such as aluminum, calcium, magnesium, zinc and silica. This thermodynamic study implies that all hardness cations such as aluminum, calcium and magnesium already have precipitates with boron under current normal plant operating conditions. However, In-core boiling can increase the amount of precipitates with silica, such as CaB2O4 and CaMg(SiO3)2. For all cases modeled, a 1 ppm silica concentration will not result in precipitation of SiO2

  20. Comparison of Remotely Sensed Precipitation and Evapotranspiration Products for a Statewide Water Assessment of New Mexico

    Schmugge, T. J.; Fernald, A.; Peterson, K.; Walker, S.; Hewitt, I. C.; Hendrickx, J. M. H.

    2014-12-01

    Precipitation and evapotranspiration (ET) are the major components of the water balance in New Mexico. Therefore, it is critical to acquire accurate precipitation and ET data as input into a statewide water balance. Since existing meteorological stations in New Mexico don't cover the entire state and leave many areas without accurate information, we propose to evaluate the accuracy of existing nationwide remotely sensed databases for precipitation and ET to quantify the spatial and temporal distributions of those components in a statewide water balance. In this study we compare five precipitation products and three ET products: the CHIRPS (Climate Hazard Group InfraRed Precipitation with Station data) model, the National Weather Service Advanced Hydrologic Prediction Service product, the PERSIANN-GCCS (Precipitation Estimation from Remote Sensed Information using Artificial Neural Network - Global Cloud Classification System) model, the PRISM (Parameter-elevation Relationships on Independent Slopes) model the TRMM (Tropical Rainfall Measuring Mission, the ALExI (Atmosphere-Land Exchange Inverse) model, the MOD 16 ( MODIS Global Evapotranspiration Product) model of NASA, and the SSEB (Simplified Surface Energy Balance) model produced by the USGS. Early results show a strong relationship between all precipitation products across the state of New Mexico from 2000 to 2013 with an average depth of 315 mm, except for the PERSIANN model which has a rainfall depth approximately 53% higher (673mm) than the average of the other models. Additionally there is a strong relationship between the ALExI and SSEB ET models yet these models exceed the precipitation in the state by approximately 35%. The MOD 16 ET model has an average ET depth approximately 42% less than the average of the precipitation models and about 60% less than the ALExI and SSEB ET models. Future work includes validation of precipitation and ET models using high density rain gauge networks, as well as METRIC

  1. Assessment of Remotely-Sensed precipitation products across the Saudi Arabia Region

    Kheimi, M.

    2012-12-01

    Water resources controlling, predicting, and decision making require a high resolution and reliable estimates of precipitation. Precipitation events significantly important and have a huge impact on the economy, the environment, and the society, especially in the largely arid countries. Recently, with the leap of developing satellite-retrieved precipitation products with high special resolution and global coverage that resulted in new source of sustainable precipitation estimates. However, the incorporation between satellite- retrieved estimates and the operational decision making are not well recognized due to lack of information towards uncertainties and consistency. In this study, the primary goal was to evaluate the performance of satellite products rainfall estimator (TRMM-3B42) and (PERSSIAN)around Saudi Arabia, by analyzing the TRMM-3B42 product for the period of January 2000- October 2010 and the PERSSIAN product for the period of March 2000 until December 2007. Independent rain gauge data were collected from over 29 local precipitation gauge stations from all thirteen provinces located in Saudi Arabia. After aggregation and interpolation, this data was specifically used to diagnose systematic differences between in-situ based rainfall and satellite derived rainfall using an extensive selection of validation metrics. The results show according to the probability of detecting rainfall amounts and volume of correctly identified precipitation, TRMM data sets led to better estimates and high correlation than PERSIANN product. Whereas in the false alarms ratio is higher in TRMM than in PERSSIAN. In fact, all precipitation products tend to miss a significant amount of rainfall. From the analysis, a recommendation suggested to extend the efforts towards necessary development of algorithms that capture precipitation with more consistency.

  2. Assessing the Impact of Antarctic Oscillation on Precipitation Variability over the La Plata River Basin

    Rocha, R. M.; Nunes, A.

    2012-12-01

    Although several studies have considered the phase changes of the Antarctic Oscillation (AAO) - the dominant mode of the Southern Hemisphere (SH) extra-tropical circulation - as one of the driven mechanisms in the SH precipitation inter-annual variability, relatively few studies have addressed the AAO phase change impacts on South American precipitation variability. Those studies found that positive (negative) AAO phase reduces (intensifies) precipitation over southeastern South America, and modulates ENSO's influence on that region. During the austral summer, the inter-annual tropical activity intensification (reduction) has been associated with AAO negative (positive) phase, as well as the corresponding variability in the positioning of the subtropical upper-level jet. In this study, the AAO phases were associated with precipitation patterns that affect water supplies for densely cultivated areas in the southeastern South America, more specifically over the La Plata River basin, taking into account the AAO seasonal index and satellite-based precipitation estimates. Changes found in the positioning and intensity of the upper-level jet were also associated with the AAO phases, and ultimately related to precipitation variability.

  3. Early assessment of Integrated Multi-satellite Retrievals for Global Precipitation Measurement over China

    Guo, Hao; Chen, Sheng; Bao, Anming; Behrangi, Ali; Hong, Yang; Ndayisaba, Felix; Hu, Junjun; Stepanian, Phillip M.

    2016-07-01

    Two post-real time precipitation products from the Integrated Multi-satellite Retrievals for Global Precipitation Measurement Mission (IMERG) are systematically evaluated over China with China daily Precipitation Analysis Product (CPAP) as reference. The IMERG products include the gauge-corrected IMERG product (IMERG_Cal) and the version of IMERG without direct gauge correction (IMERG_Uncal). The post-research TRMM Multisatellite Precipitation Analysis version 7 (TMPA-3B42V7) is also evaluated concurrently with IMERG for better perspective. In order to be consistent with CPAP, the evaluation and comparison of selected products are performed at 0.25° and daily resolutions from 12 March 2014 through 28 February 2015. The results show that: Both IMERG and 3B42V7 show similar performances. Compared to IMERG_Uncal, IMERG_Cal shows significant improvement in overall and conditional bias and in the correlation coefficient. Both IMERG_Cal and IMERG_Uncal perform relatively poor in winter and over-detect slight precipitation events in northwestern China. As an early validation of the GPM-era IMERG products that inherit the TRMM-era global satellite precipitation products, these findings will provide useful feedbacks and insights for algorithm developers and data users over China and beyond.

  4. Comparative study on precipitation methods of yellow-cake from acid leachate of rock phosphate and Its purification

    This study was carried-out to leach uranium from rock phosphate using sulphuric acid in presences of potassium chlorate as an oxidant and to investigate the relative purity of different forms of yellow cakes produced with ammonia ((NH4)2 U2 O7), magnesia (UO3.xH2O) and sodium hydroxide (Na2U2O7) as precipitants, as well as purification of the products with TBP extraction and matching its impurity levels with specification of the commercial products. Alpha-particle spectrometry was for used for determination of activity concentration of uranium isotopes (''2''3''4U and ''2''3''8U) in rock phosphate, resulting green phosphoric acid solution, and in different forms of the yellow cake from which the equivalent mass concentration of uranium was deduced. Likewise, AAS was used for determination of impurities (Pb, Ni, Cd, Fe, Zn, Mn, and Cu). On the average, the activity concentration of uranium in the rock phosphate was 1468±979 Bq/Kg (119.38±79.66 ppm), and 711±252 Bq/L (57.85±20.46 ppm) in the resulting green solution with corresponding percent of dissolution amounting to 48% which is considered low indicating that the experimental conditions (i.e. dissolution container, temperature, PH, retention time) were not optimal. However, the isotopic ratio (''2''3''4U, ''2''3''8U) in all stages of hydrometallurgical process was not much different from unity indicating lack of fractionation. Crude yellow cakes (hydrate uranium trioxide, ammonium diuranate and sodium diuranate) were precipitated from the green solutions prior to separation of iron and once after iron separation. Although, iron was tested using bipyridine and SCN, it was found in all types of crude samples analyzed this might be attributed to either the quality of the reagent used or inhibition of Fe present in the solution by stronger complexing agent. Uranium mass concentration in crude yellow cakes precipitated before iron separation was found following the order: UO3.xH2O>ammonium diuranate

  5. 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

    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.

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

    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. PMID:21930525

  7. Nickel recovery from spent Raneynickel catalyst through dilute sulfuric acid leaching and soda ash precipitation.

    Lee, Jin Young; Rao, S Venkateswara; Kumar, B Nagaphani; Kang, Dong Jun; Reddy, B Ramachandra

    2010-04-15

    Pharmaceutical industry makes extensive use of Raneynickel catalyst for various organic drug intermediates/end products. Spent catalysts contain environmentally critical and economically valuable metals. In the present study, a simple hydrometallurgical process using dilute sulfuric acid leaching was described for the recovery of nickel from spent Raneynickel catalyst. Recovery of nickel varied with acid concentration and time, whereas temperature had negligible effect. Increase of S/L ratio to 30% (w/v) showed marginal effect on nickel (90%) recovery, whereas Al recovery decreased drastically to approximately 20%. Under the optimum conditions of leaching viz: 12 vol.% H(2)SO(4), 30 degrees C, 20% solid to liquid (S/L) ratio and 120 min reaction time, it was possible to recover 98.6% Ni along with 39.2% Al. Leach liquor [pH 0.7] containing 85.0 g/L Ni and 3.25 g/L Al was adjusted to pH 5.4 with 30 wt.% alkali for quantitative aluminum removal. Nickel loss was about 2% during this Al removal step. Nickel from the purified leach liquor was recovered as nickel carbonate by adding required amount of Na(2)CO(3). The purity of NiCO(3) product was found to be 100% with a Ni content of 48.6%. Na(2)SO(4) was recovered as a by-product with a purity of 99%. Complete process is presented. PMID:20018448

  8. Assessing the diurnal cycle of precipitation in a multi-scale climate model

    Michael S Pritchard

    2009-10-01

    Full Text Available A promising result that has emerged from the new Multi-scale Modeling Framework (MMF approach to atmospheric modeling is a global improvement in the daily timing of peak precipitation over the continents, which is suggestive of improved moist dynamics at diurnal timescales overall. We scrutinize the simulated seasonal composite diurnal cycle of precipitation in an MMF developed by the Center for Multiscale Modeling of Atmospheric Processes (CMMAP using a comprehensive suite of diurnal cycle diagnostics including traditional harmonic analysis, and non-traditional diagnostics such as the broadness of the peak precipitation in the mean summer day, reduced dimension transect analysis, and animations of the full spatial and temporal variability of the composite mean summer day. Precipitation in the MMF is evaluated against multi-satellite merged satellite data and a control simulation with a climate model that employs conventional cloud and boundary layer parameterizations. Our analysis highlights several improved features of the diurnal cycle of precipitation in the multi-scale climate model: It is less sinusoidal over the most energetic diurnal rainfall regimes, more horizontally inhomogeneous within continents and oceans, and more faithful to observed structural transitions in the composite diurnal cycle chronology straddling coastlines than the conventional climate model. A regional focus on North America links a seasonal summer dry bias over the continental United States in the CMMAP MMF at T42 resolution to its inability to capture diurnally propagating precipitation signals associated with organized convection in the lee of the Rockies. The chronology of precipitation events elsewhere in the vicinity of North America is improved in the MMF, especially over sea breeze circulation regions along the eastern seaboard and the Gulf of Mexico, as well as over the entirety of the Gulf Stream. Comparison of the convective heating and moistening

  9. Interaction between uranium and humic acid (II): complexation, precipitation and migration behavior of U(VI) in the presence of humic substances

    The complexation, precipitation, and migration behavior of uranium in the presence of humic acid (HA) or fulvic acid (FA) were investigated by cation exchange, ultrafiltration and dynamic experiment, respectively. The results showed that (i) complex equilibrium between the uranium and humic substances was achieved at approximately 72 h, (ii) the coordination number varied from 1:1 to 1:2 (U(VI): humic acid) as pH increased from 3 to 6; and (iii), while the complex stability constant decreased when temperature increased, but increased with pH value. We found that the precipitation of uranyl could only be observed in presence of HA, and the precipitation was influenced by conditions, such as pH, uranium concentration, temperature, and the HA concentration. The maximum precipitation proportion up to 60% could be achieved in the condition of 40 mg/L HA solution at pH 6. We further observed that the migration behavior of uranium in soil in the presence of humic acid (HA) or fulvic acid (FA) was different from that in the presence of inorganic colloid, and the effect of humic substances (HS) was limited. (authors)

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

    Zhu, Lin; Gong, Huili; 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...

  11. Assessing the Capabilities of Three Regional Climate Models over CORDEX Africa in Simulating West African Summer Monsoon Precipitation

    Akinsanola, A. A.; K. O. Ogunjobi; Gbode, I. E.; Ajayi, V. O.

    2015-01-01

    This study evaluates the ability of three Regional Climate Models (RCMs) used in Coordinated Regional Climate Downscaling Experiment (CORDEX) to simulate the characteristics of rainfall pattern during the West Africa Summer Monsoon from 1998 to 2008. The seasonal climatology, annual rainfall cycles, and wind fields of the RCMs output were assessed over three homogenous subregions and validated using precipitation data from eighty-one (81) ground observation stations and TRMM satellite data. F...

  12. LiCoO 2 sub-microns particles obtained from micro-precipitation in molten stearic acid

    Lala, S. M.; Montoro, L. A.; Rosolen, J. M.

    The present work reports a novel emulsion method for preparation of lithium cobalt oxide based on the micro-precipitation of lithium and cobalt salts in molten stearic acid. The precursors consist of micro-aggregated powders of CoOOH and CH 3(CH 2) 16COOLi whose formation depends on the concentration of stearic acid used in the synthesis. The micro-aggregated of CoOOH and CH 3(CH 2) 16COOLi when calcined at 800 °C yielded well-crystalline sub-microns particles of LiCoO 2 ( R-3 m) with a very uniform shape (quasi-hexagonal pellets), a very narrow grain size distribution ( d10=0.31, d50=3.14, d90=6.30 μm) and high specific surface area (7.4 m 2 g -1). The long life reversible specific capacity of the mp-LiCoO 2 composite electrode subsequently made was 110 mAh g -1 for initial deinsertion 165 mAh g -1.

  13. Adsorption compared with sulfide precipitation as metal removal processes from acid mine drainage in a constructed wetland

    Machemer, Steven D.; Wildeman, Thomas R.

    1992-01-01

    Metal removal processes from acid mine drainage were studied in an experimental constructed wetland in the Idaho Springs-Central City mining district of Colorado. The wetland was designed to passively remove heavy metals from the mine drainage flowing from the Big Five Tunnel. Concurrent studies were performed in the field on the waters flowing from the wetland and in the laboratory on the wetland substrate. Both studies suggest that there is competition for organic adsorption sites among Fe, Cu, Zn and Mn. Iron and Cu appear to be more strongly adsorbed than Zn and Mn. The adsorption of metals varies with the fluctuation of pH in the outflow water. Also indicated by field and laboratory studies is the microbial reduction of sulfate with a corresponding increase in the sulfide concentration of the water. As sulfide is generated. Cu and Zn are completely removed. The field results suggest that upon start up of a constructed wetland, the adsorption of dissolved metals onto organic sites in the substrate material will be an important process. Over time, sulfide precipitation becomes the dominant process for metal removal from acid mine drainage.

  14. Assessment of various convective parametrisation schemes for warm season precipitation foracasts

    Mazarakis, Nikos; Kotroni, Vassiliki; Lagouvardos, Konstantinos; Argyriou, Athanassios

    2010-05-01

    In the frame of the EU/FP6-funded FLASH project the sensitivity of numerical model quantitative precipitation forecasts to the choice of the convective parameterization scheme (CPS) has been examined for twenty selected cases characterized by intense convective activity and widespread precipitation over Greece, during the warm period of 2005 - 2007. The schemes are: Kain - Fritsch, Grell and Betts - Miller - Janjic. The simulated precipitation from the 8-km grid was verified against raingauge measurements and lightning data provided by the ZEUS long-range lightning detection system. The validation against both sources of data showed that among the three CPSs, the more consistent behavior in quantitative precipitation forecasting was obtained by the Kain - Fritsch scheme that provided the best statistical scores. Further various modifications of the Kain-Fritsch (KF) have been examined. The modifications include: (a) the maximization of the convective scheme precipitation efficiency, (b) the change of the convective time step, (c) the force of the convective scheme to produce more/less cloud material, (d) the alteration of the vertical profile of updraft mass flux detrainment.

  15. A stochastic assessment of climate change impacts on precipitation and potential evaporation in Alberta

    Vashchyshyn, I.; Wheater, H. S.; Chun, K.

    2012-12-01

    In many climate change investigations, changes in precipitation are projected under various scenarios; however, changes in evaporation have received relatively less attention. For irrigation and water resources management, the difference between potential evaporation and precipitation can provide better quantification of local water availability and drought conditions. Therefore, projecting joint variations in precipitation and potential evaporation can provide better information for climate change adaptation. A stochastic approach based on a Generalised Linear Model (GLM) framework is proposed to study these together at a station scale. Eight stations in Alberta are selected for which historical pan evaporation records and up-to-date meteorological information are available. Results show that potential evaporation estimated from Global Circulation Models directly can be unreliable. The evaporation ensemble simulated by the GLM approach can represent observed evaporation more realistically and provide better uncertainty quantification. If only simulated precipitation is considered, the projected drought conditions in the 2080s are likely to be less severe than that in the 2000s. However, the projected difference between precipitation and evaporation (water deficit) shows that the future drought conditions may be higher or lower, varying between the stations. Implications of the results and further development of the proposed approach to address spatial dependence between stations are also discussed.

  16. Robust assessment of future changes in extreme precipitation over the Rhine basin using a GCM

    S. F. Kew

    2010-11-01

    Full Text Available Estimates of future changes in extremes of multiday precipitation sums are critical for estimates of future discharge extremes of large river basins. Here we use a large ensemble of global climate model SRES A1b scenario simulations to estimate changes in extremes of 1–20 day precipitation sums over the Rhine basin, projected for the period 2071–2100 with reference to 1961–1990.

    We find that in winter, an increase of order 10%, for the 99th percentile precipitation sum, is approximately fixed across the selected range of multiday sums, whereas in summer, the changes become increasingly negative as the summation time lengthens. Explanations for these results are presented that have implications for simple scaling methods for creating time series of a future climate. We show that this scaling behavior is sensitive to the ensemble size and indicate that currently available discharge estimates from previous studies are based on insufficiently long time series.

  17. Assessment of future variability in extreme precipitation and the potential effects on the wadi flow regime.

    Gunawardhana, Luminda Niroshana; Al-Rawas, Ghazi A; Kazama, So; Al-Najar, Khalid A

    2015-10-01

    The objective of this study is to investigate how the magnitude and occurrence of extreme precipitation events are affected by climate change and to predict the subsequent impacts on the wadi flow regime in the Al-Khod catchment area, Muscat, Oman. The tank model, a lumped-parameter rainfall-runoff model, was used to simulate the wadi flow. Precipitation extremes and their potential future changes were predicted using six-member ensembles of general circulation models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5). Yearly maxima of the daily precipitation and wadi flow for varying return periods were compared for observed and projected data by fitting the generalized extreme value (GEV) distribution function. Flow duration curves (FDC) were developed and compared for the observed and projected wadi flows. The results indicate that extreme precipitation events consistently increase by the middle of the twenty-first century for all return periods (49-52%), but changes may become more profound by the end of the twenty-first century (81-101%). Consequently, the relative change in extreme wadi flow is greater than twofolds for all of the return periods in the late twenty-first century compared to the relative changes that occur in the mid-century period. Precipitation analysis further suggests that greater than 50% of the precipitation may be associated with extreme events in the future. The FDC analysis reveals that changes in low-to-moderate flows (Q60-Q90) may not be statistically significant, whereas increases in high flows (Q5) are statistically robust (20 and 25% for the mid- and late-century periods, respectively). PMID:26370197

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

    T. A. McMahon

    2014-05-01

    Full Text Available 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

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

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

    extreme value statistics of the RCM data, and application of a stochastic weather generator fitted to the changes in rainfall characteristics from the RCM data. The results show a large variability in the projected changes in extreme precipitation between the different RCMs and the two estimation methods...

  20. Occult precipitation in the highest mountains of the Czech Republic – monitoring, assessment and time variation

    Tesař, Miroslav; Šír, Miloslav; Fottová, D.

    Santa Cruz : University of Santa Cruz, 2006 - (Crow, S.). s. 215 [BIOGEOMON. International Symposium on Ecosystem Behavior /5./. 25.06.2006-30.06.2006, Santa Cruz] R&D Projects: GA AV ČR IAA3042301 Institutional research plan: CEZ:AV0Z20600510 Keywords : occult precipitation Subject RIV: DA - Hydrology ; Limnology

  1. Assessment of climate variations in temperature and precipitation extreme events over Iran

    Soltani, M.; Laux, P.; Kunstmann, H.; Stan, K.; Sohrabi, M. M.; Molanejad, M.; Sabziparvar, A. A.; Ranjbar SaadatAbadi, A.; Ranjbar, F.; Rousta, I.; Zawar-Reza, P.; Khoshakhlagh, F.; Soltanzadeh, I.; Babu, C. A.; Azizi, G. H.; Martin, M. V.

    2015-09-01

    In this study, changes in the spatial and temporal patterns of climate extreme indices were analyzed. Daily maximum and minimum air temperature, precipitation, and their association with climate change were used as the basis for tracking changes at 50 meteorological stations in Iran over the period 1975-2010. Sixteen indices of extreme temperature and 11 indices of extreme precipitation, which have been quality controlled and tested for homogeneity and missing data, are examined. Temperature extremes show a warming trend, with a large proportion of stations having statistically significant trends for all temperature indices. Over the last 15 years (1995-2010), the annual frequency of warm days and nights has increased by 12 and 14 days/decade, respectively. The number of cold days and nights has decreased by 4 and 3 days/decade, respectively. The annual mean maximum and minimum temperatures averaged across Iran both increased by 0.031 and 0.059 °C/decade. The probability of cold nights has gradually decreased from more than 20 % in 1975-1986 to less than 15 % in 1999-2010, whereas the mean frequency of warm days has increased abruptly between the first 12-year period (1975-1986) and the recent 12-year period (1999-2010) from 18 to 40 %, respectively. There are no systematic regional trends over the study period in total precipitation or in the frequency and duration of extreme precipitation events. Statistically significant trends in extreme precipitation events are observed at less than 15 % of all weather stations, with no spatially coherent pattern of change, whereas statistically significant changes in extreme temperature events have occurred at more than 85 % of all weather stations, forming strongly coherent spatial patterns.

  2. In vitro risk assessment of usnic acid.

    Polat, Zühal; Aydın, Elanur; Türkez, Hasan; Aslan, Ali

    2016-03-01

    Lichens are symbiotic organisms composed of fungi and algae and are very common in Turkey. Lichen secondary metabolites are mainly phenolic compounds produced by fungal partner of lichen symbiosis. Usnic acid (UA) is one of the most common lichen metabolites, and it was reported that to be effective for a wide range of pharmacological purposes including antiviral, antitumor, and antiprotozoal. However, there are limited data on the genotoxic and antioxidant effects of UA in cultured human peripheral blood cells. Therefore, the aim of this thesis study was to investigate the genetic and oxidative effects of UA in cultured human blood cells (n = 5). The UA was added into culture tubes at various concentrations (0-200 μg/ml). Chromosomal aberrations (CA) and micronuclei (MN) tests were performed for genotoxic damage influences estimation. In addition, biochemical parameters (total antioxidant capacity (TAC) and total oxidative status (TOS)) were examined to determine oxidative effects. In our in vitro test systems, it was observed that UA had no mutagenic effects on human lymphocytes. Furthermore, our results indicated that low concentrations (1 and 5 μg/ml) of UA caused increases of TAC levels in cultured human blood cells. And, the TOS levels were not changed (p > 0.05) when all the concentrations (except for 200 μg/ml) of UA were applied. In conclusion, UA can be a new resource of therapeutics as recognized in this study with their nonmutagenic and antioxidant features. PMID:24193043

  3. Assessing the relative influence of surface soil moisture and ENSO SST on precipitation predictability over the contiguous United States

    Yoon, Jin-Ho; Leung, Lai-Yung R.

    2015-06-28

    This study assesses the relative influence of soil moisture memory and tropical sea surface temperature (SST) in seasonal rainfall over the contiguous United States. Using observed precipitation, the NINO3.4 index and soil moisture and evapotranspiration simulated by a land surface model for 61 years, analysis was performed using partial correlations to evaluate to what extent land surface and SST anomaly of El Niño and Southern Oscillation (ENSO) can affect seasonal precipitation over different regions and seasons. Results show that antecedent soil moisture is as important as concurrent ENSO condition in controlling rainfall anomalies over the U.S., but they generally dominate in different seasons with SST providing more predictability during winter while soil moisture, through its linkages to evapotranspiration and snow water, has larger influence in spring and early summer. The proposed methodology is applicable to climate model outputs to evaluate the intensity of land-atmosphere coupling and its relative importance.

  4. Flow cytometric assessment of viability of lactic acid bacteria

    Bunthof, C.J.; Bloemen, K.; Breeuwer, P.; Rombouts, F. M.; Abee, T

    2001-01-01

    The viability of lactic acid bacteria is crucial for their applications as dairy starters and as probiotics. We investigated the usefulness of flow cytometry (FCM) for viability assessment of lactic acid bacteria. The esterase substrate carboxyfluorescein diacetate (cFDA) and the dye exclusion DNA binding probes propidium iodide (PI) and TOTO-1 were tested for live/dead discrimination using a Lactococcus, a Streptococcus, three Lactobacillus, two Leuconostoc, an Enterococcus, and a Pediococcu...

  5. The Contribution of Amazonian Evapotranspiration to Precipitation over South America: Assessing the Role of Groundwater

    Martinez-Agudelo, J. A.; Dominguez, F.; Miguez-Macho, G.

    2013-12-01

    The Amazon forest faces both continued deforestation and climate change in the future. For this reason, it is important to understand and quantify the role that the Amazonian forest plays in the climate of South America. In this work, we first delineate the geographical extent and spatiotemporal variability of precipitation that originates as Amazonian evapotranspiration (ET). To do this we use ERA-Interim reanalysis data as input for the Dynamic Recycling Model DRM for the period 1980-2012. We find that the northern Amazon contributes mostly to moisture over northern South America during the May-October period as mean vertically integrated water vapor transport north of 5°S becomes southerly during this time. Nearly 12% of the mean annual precipitation over northern South America originates in northern Amazon, with relatively large variations during the year. The southern Amazon region, on the other hand, contributes mostly to southern South America. Mean precipitation in La Plata Basin originating from southern Amazon ET is approximately 19%, reaching values of 27% during the dry season (in contrast, local recycling from La Plata during this season is approximately 20%). Contributions to atmospheric moisture from the Amazon to the rest of the continent are smaller than the corresponding oceanic contributions, but still significant in the hydrologic cycle. Interestingly, we find that variations in water vapor and precipitation originating from the Amazon have a stronger dependence on the atmospheric circulation than on ET production. In the second part of this study we evaluate the role of groundwater on surface ET and continental moisture transport. To do this we run simulations using the WRF-LEAF-Hydro-Flood model where groundwater and flooding dynamics are explicitly represented. These two components have been shown to affect ET patterns over South America, especially over the southern Amazon. We use ERA-Interim reanalysis as lateral boundary condition for

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

    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.

  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.

    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. Augmenting acid with affective details to assess credibility

    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.

  9. Batch test assessment of waste-to-energy combustion residues impacts on precipitate formation in landfill leachate collection systems.

    Cardoso, Antonio J; Levine, Audrey D; Rhea, Lisa R

    2008-01-01

    Disposal practices for bottom ash and fly ash from waste-to-energy (WTE) facilities include emplacement in ash monofills or co-disposal with municipal solid waste (MSW) and residues from water and wastewater treatment facilities. In some cases, WTE residues are used as daily cover in landfills that receive MSW. A recurring problem in many landfills is the development of calcium-based precipitates in leachate collection systems. Although MSW contains varying levels of calcium, WTE residues and treatment plant sludges have the potential to contribute concentrated sources of leachable minerals into landfill leachates. This study was conducted to evaluate the leachability of calcium and other minerals from residues generated by WTE combustion using residues obtained from three WTE facilities in Florida (two mass-burn and one refuse-derived fuel). Leaching potential was quantified as a function of contact time and liquid-to-solid ratios with batch tests and longer-term leaching tests using laboratory lysimeters to simulate an ash monofill containing fly ash and bottom ash. The leachate generated as a result of these tests had total dissolved solid (TDS) levels ranging from 5 to 320 mg TDS/g ash. Calcium was a major contributor to the TDS values, contributing from 20 to 105 g calcium/kg ash. Fly ash was a major contributor of leachable calcium. Precipitate formation in leachates from WTE combustion residues could be induced by adding mineral acids or through gas dissolution (carbon dioxide or air). Stabilization of residual calcium in fly ashes that are landfilled and/or the use of less leachable neutralization reagents during processing of acidic gases from WTE facilities could help to decrease the calcium levels in leachates and help to prevent precipitate formation in leachate collection systems. PMID:18236791

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

    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. PMID:26062529

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

    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.

  12. Behaviour of the pH adjustment, Ion exchange and concentrate precipitation stages in the acid leaching of uranium phosphate ores

    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

  13. Study on uranium loss during 'Iron-Gypsum Cake' precipitation from acid leach liquor of Jaduguda ore using factorially designed experiments

    Acid leaching process for uranium recovery from ore often generates considerable amounts of impurities into the solution. It is a challenge to separate the non-valuable impurities as manageable and stable waste products for final disposal, without losing the valuable constituents. The main impurities that come with the leach liquor are iron and sulfate. Their removal is essential for meeting the iron requirement in leaching circuit and also for making the effluent suitable for recycle. Factorial design analysis was applied to study of process variables for precipitation of iron and sulphate from leach liquor with composition using CaO as precipitation reagent

  14. Glycolic Acid Physical Properties, Impurities, And Radiation Effects Assessment

    The 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 H2 and cause an adverse effect in the SRAT or SME process. It has been cited that glycolic acid solutions that are depleted of O2 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 pumping of the solution may be hindered. A series

  15. MODIFICATION OF PRECIPITATED CALCIUM CARBONATE FILLER USING SODIUM SILICATE/ZINC CHLORIDE BASED MODIFIERS TO IMPROVE ACID-RESISTANCE AND USE OF THE MODIFIED FILLER IN PAPERMAKING

    Jing Shen

    2009-11-01

    Full Text Available In order to improve the acid-resistant property of papermaking grade precipitated calcium carbonate filler and to obtain modified filler in powder form, sodium silicate/zinc chloride based modifiers were used in filler modification, and the use of modified filler in papermaking of deinked pulp derived from recycled newspaper was also preliminarily investigated. Under the preliminarily optimized experimental conditions, when sodium silicate, zinc chloride, sodium hexametaphosphate, and phosphoric acid with dosages of 10 wt%, 3 wt%, 1 wt% and 0.2 wt%, respectively, were used as modifiers, and when the temperature, aging time, and PCC concentration during the filler modification process was 70 oC, 7 h and 9.1 wt%, respectively, the acid-resistant property of filler was significantly improved after modification, as evaluated using alum consumption and pH methods. The use of modified precipitated calcium carbonate filler prepared under the optimized conditions provided considerably more brightness and light scattering improvement in comparison to unmodified filler, and filler modification was found to have only negligible influence on tensile and burst strength of the paper, air permeability of the paper, and retention performance of the filler. Surface analysis of the modified filler using XPS and SEM confirmed the occurring of surface encapsulation and modification of precipitated calcium carbonate filler when the relevant modifiers were used in filler modification. The encapsulating effect of modifiers on filler was thought to be favorable to improvement in acid-resistant property, and optical properties of the filled paper.

  16. Assessing the costs and market impacts of carbon sequestration, climate change, and acid rain

    This thesis provides fourteen journal articles and papers. Thirteen of these papers were published in referred journals, covering environmental economics, policy modelling, policy analysis, and the physical sciences. One paper was published as a USDA Forest Service research report. The papers in the thesis are divided into three topical areas: 1) Section 2: The Economics of Carbon Sequestration. Eight papers plus Appendix A of the thesis cover the development and application of models to estimate the economic costs and management consequences of policies to sequester carbon emissions by planting trees on agricultural land in the US or through more intensive forest management. 2) Section 3: The Economics of Climate Change Damages. Two papers of the thesis cover the development of models that can be used to estimate the market and nonmarket damages associated with the impacts of climate change on water resources in the US. 3) Section 4: The Economics of Acid Rain Damages. Three papers in the thesis examine the methods that were developed to estimate the damages due to acid rain in the US by the National Acid Precipitation Assessment Program (NAPAP) and discuss more generally the role of economic policy analysis in this assessment. (EHS)

  17. Assessment of sulfate sources in high-elevation Asian precipitation using stable sulfur isotopes.

    Pruett, Lee E; Kreutz, Karl J; Wadleigh, Moire; Aizen, Vladimir

    2004-09-15

    Stable sulfur isotope measurements (delta34S) made on samples collected from a 2 m snowpit on the Inilchek Glacier, Tien Shan Mountains (42.16 degrees N, 80.25 degrees E, 5100 m) are used to estimate sources of sulfate (SO4(2-)) in high-elevation Central Asian precipitation. Comparison of snowpit oxygen isotope (delta18O) data with previous work constrains the age of the snowpit samples to the summer season during which they were retrieved (1999). Delta34S measurements were made at 10 cm resolution (20 samples total), with delta34S values ranging from 0.4/1000 during background ([SO4(2-)] Tien Shan snowpit provide the first unambiguous identification of evaporite and anthropogenic SO4(2-) in high-elevation Asian precipitation, and future ice core studies using improved analysis techniques and source delta34S values can provide detailed information on sulfur biogeochemistry and anthropogenic impacts in Asian alpine regions. PMID:15487779

  18. Assessing the Impact of Changes in Extreme Precipitation Events on Landslide Occurrence and Resultant Human Cost (Invited)

    Markuzon, N.; Slesnick, C.; Bellugi, D. G.; Leidy, E.; O'Gorman, P. A.; Perron, J.; Regan, J.; Schlosser, C. A.; West, J.

    2013-12-01

    Observations demonstrate that extreme precipitation events are a primary driver of shallow landslides. Thus, as the character of precipitation extremes shift under climate change, the occurrence of landslides is expected to shift in response. Mitigation of future damage requires an increased understanding of how evolving environmental phenomena affect landslide occurrence and severity. We are carrying out a study that integrates remotely-sensed and ground based observational data of precipitation, topography, and land cover with global and regional climate models and anthropogenic data. The approach fuses newly developed mechanistic models of local slope stability with novel weather based data-driven models with the aim of understanding factors contributing to landslide occurrence and producing temporal and spatial projections. Our methodology adopts a mechanistic landslide prediction procedure which couples a three-dimensional slope stability model with an efficient search algorithm to predict discrete shallow landslides for a prototype landscape located in the Oregon Coast Range.The procedure reproduces the distribution of sizes and locations of the landslide inventory under a suite of rainfall and moisture characteristics representative of the observation period. We are using projections of precipitation extremes under different climate change scenarios to generate landslide forecasts and explore the sensitivity of landslide characteristics to precipitation patterns. Data-driven models can help to improve the accuracy of the mechanistic landslide hindcasts by calibrating the soil parameters in the slope stability model based on remotely sensed proxies for land cover and vegetation characteristics. We further aim to fuse the mechanistic and data-driven models with the goal of forecasting landslide risk under severe weather conditions from remotely-sensed data in areas where high resolution in-situ observations are not available. Using statistical analysis and

  19. Analysis of fish otoliths by electrothermal vaporization inductively coupled plasma mass spectrometry: aspects of precipitating otolith calcium with hydrofluoric acid for trace element determination.

    Arslan, Zikri

    2005-03-15

    A method is developed for determination of trace elements, including Ag, As, Cd, Co, Cr, Cu, Mn, Ni, Se, Tl and Zn, in fish otoliths by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS). Hydrofluoric acid was used to precipitate calcium resulting from acid dissolution of otolith calcium carbonate. Initial acidity of the sample solution influenced the precipitation efficiency of calcium fluoride. Up to 99.5% of Ca was precipitated in solutions that contained less than 2% (v/v) HNO(3). Recoveries of the elements obtained from spiked artificial otolith solutions were between 90 and 103%. Stabilization of the elements within the ETV cell was achieved with 0.3mug Pd/0.2mug Rh chemical modifier that also afforded optimum sensitivity for multielement determination. The method was validated by the analysis of a fish otolith reference material (CRM) of emperor snapper, and then applied to the determination of the trace elements in otoliths of several fish species captured in Raritan Bay, New Jersey. Results indicated that fish physiology and biological processes could influence the levels of Cu, Mn, Se and Zn in the otoliths of fish inhabiting a similar aqueous environment. Otolith concentrations of Cr and Ni did not show any significant differences among different species. Concentrations for Ag, As, Cd, Co and Tl were also not significantly different, but were very low indicating low affinity of otolith calcium carbonate to these elements. PMID:18969949

  20. Bioavailability of zinc to rats from defatted soy flour, acid-precipitated soy concentrate and neutralized soy concentrate as determined by intrinsic and extrinsic labeling techniques

    The bioavailability of 65Zn from intrinsically and extrinsically labeled soy flour, acid-precipitated soy concentrate and neutralized soy concentrate was evaluated in rats. Weanling rats were fed marginally zinc-deficient diets, providing 8 ppm zinc from one of these three soy products, for 7 days. The rats then received a radioactively labeled test meal, identical in composition to the previous diet except that the soy product was either intrinsically or extrinsically labeled with 65Zn. After the test meal the rats were again fed diets the same as those consumed prior to the test meal. Whole-body retention of 65Zn at 24 hours and 12 days as well as 65Zn retained in tibias of rats given meals containing neutralized concentrate-based meals was significantly lower than for rats given meals containing the soy flour or acid-precipitated concentrate. In addition, retention of 65Zn from the extrinsically labeled acid-precipitated concentrate-based meal was significantly higher than from the same product intrinsically labeled. These findings confirm the results of previous feeding studies from which it was suggested that neutralization of soy protein concentrates reduces zinc bioavailability to the rat. In addition, the results are taken to suggest that experimental conditions may influence the validity of the extrinsic labeling technique for zinc

  1. Analytical Methods for Environmental Risk Assessment of Acid Sulfate Soils: A Review

    2001-01-01

    Assessment of acid sulfate soil risk is an important step for acid sulfate soil management and its reliability depends very much on the suitability and accuracy of various analytical methods for estimating sulfide-derived potential acidity, actual acidity and acid-neutralizing capacity in acid sulfate soils. This paper critically reviews various analytical methods that are currently used for determination of the above parameters, as well as their implications for environmental risk assessment of acid sulfate soils.

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

    Pušnik, Klementina; Goršak, Tanja; Drofenik, Miha; Makovec, Darko

    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 Fe3+/Fe2+ 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 Fe3+ 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.

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

    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

  4. A perspective of stepwise utilisation of Bayer red mud: Step two--Extracting and recovering Ti from Ti-enriched tailing with acid leaching and precipitate flotation.

    Huang, Yanfang; Chai, Wencui; Han, Guihong; Wang, Wenjuan; Yang, Shuzhen; Liu, Jiongtian

    2016-04-15

    The extraction and recovery of Ti from Ti-enriched tailing with acid leaching and precipitate flotation, as one of the critical steps, was proposed for the stepwise utilization of red mud. The factors influencing acid leaching and precipitate flotation were examined by factorial design. The leaching thermodynamics, kinetics of Ti(4+), Al(3+) and Fe(3+), and the mechanism of selectively Fe(3+) removal using [Hbet][Tf2N] as precipitating reagent were discussed. The extracting of Ti(4+), Al(3+) and Fe(3+) in concentrated H2SO4 is controlled by diffusion reactions, depending mainly upon leaching time and temperature. The maximum extracting efficiency of Ti(4+) is approximately 92.3%, whereas Al(3+) and Fe(3+) leaching are respectively 75.8% and 84.2%. [Hbet][Tf2N], as a precipitating reagent, operates through a coordination mechanism in flotation. The pH value is the key factor influencing the flotation recovery of Ti(4+), whereas the dosage of precipitating reagent is that for Al(3+) recovery. The maximum flotation recovery of Ti(4+) is 92.7%, whereas the maximum Al(3+) recovery is 93.5%. The total recovery rate for extracting and recovering titanium is 85.5%. The liquor with Ti(4+) of 15.5g/L, Al(3+) of 30.4g/L and Fe(3+) of 0.48g/L was obtained for the following hydrolysis step in the integrated process for red mud utilisation. PMID:26799223

  5. On the use of Standardized Precipitation Index(SPI) for drought intensity assessment

    Kumar, M Naresh; Sai, M V R Sesha; Roy, P S

    2015-01-01

    Monthly rainfall data from June to October for 39 years was used to generate Standardized Precipitation Index (SPI) values based on Gamma distribution for a low rainfall and a high rainfall district of Andhra Pradesh state, India. Comparison of SPI, with actual rainfall and rainfall deviation from the mean indicated that SPI values under-estimate the intensity of dryness/wetness when the rainfall is very low/very high respectively. As a result, the SPI in the worst drought years of 2002 and 2006 in the low rainfall district has indicated only moderate dryness instead of extreme dryness. The range of SPI values of the high rainfall district indicated better stretching, compared to that of the low rainfall district. Further, the SPI values of longer time scale (2-, 3- and 4- months) showed an extended range compared to 1-month, but the sensitivity in drought years has not improved significantly. To ascertain whether non normality of SPI is a possible reason, normality tests were conducted. The Shapiro-Wilk stat...

  6. Uncertainties on mean areal precipitation: assessment and impact on streamflow simulations

    L. Moulin

    2008-08-01

    Full Text Available This paper investigates the influence of mean areal rainfall estimation errors on a specific case study: the use of lumped conceptual rainfall-runoff models to simulate the flood hydrographs of three small to medium-sized catchments of the upper Loire river. This area (3200 km2 is densely covered by an operational network of stream and rain gauges. It is frequently exposed to flash floods and the improvement of flood forecasting models is then a crucial concern. Particular attention has been drawn to the development of an error model for rainfall estimation consistent with data in order to produce realistic streamflow simulation uncertainty ranges. The proposed error model combines geostatistical tools based on kriging and an autoregressive model to account for temporal dependence of errors. It has been calibrated and partly validated for hourly mean areal precipitation rates. Simulated error scenarios were propagated into two calibrated rainfall-runoff models using Monte Carlo simulations. Three catchments with areas ranging from 60 to 3200 km2 were tested to reveal any possible links between the sensitivity of the model outputs to rainfall estimation errors and the size of the catchment. The results show that a large part of the rainfall-runoff (RR modelling errors can be explained by the uncertainties on rainfall estimates, especially in the case of smaller catchments. These errors are a major factor limiting accuracy and sharpness of rainfall-runoff simulations, and thus their operational use for flood forecasting.

  7. Uncertainties on mean areal precipitation: assessment and impact on streamflow simulations

    L. Moulin

    2009-02-01

    Full Text Available This paper investigates the influence of mean areal rainfall estimation errors on a specific case study: the use of lumped conceptual rainfall-runoff models to simulate the flood hydrographs of three small to medium-sized catchments of the upper Loire river. This area (3200 km2 is densely covered by an operational network of stream and rain gauges. It is frequently exposed to flash floods and the improvement of flood forecasting models is then a crucial concern. Particular attention has been drawn to the development of an error model for rainfall estimation consistent with data in order to produce realistic streamflow simulation uncertainty ranges. The proposed error model combines geostatistical tools based on kriging and an autoregressive model to account for temporal dependence of errors. It has been calibrated and partly validated for hourly mean areal precipitation rates. Simulated error scenarios were propagated into two calibrated rainfall-runoff models using Monte Carlo simulations. Three catchments with areas ranging from 60 to 3200 km2 were tested to reveal any possible links between the sensitivity of the model outputs to rainfall estimation errors and the size of the catchment. The results show that a large part of the rainfall-runoff (RR modelling errors can be explained by the uncertainties on rainfall estimates, especially in the case of smaller catchments. These errors are a major factor limiting accuracy and sharpness of rainfall-runoff simulations, and thus their operational use for flood forecasting.

  8. Preliminary assessment of a method utilizing carbon dioxide and steelmaking slags to produce precipitated calcium carbonate

    Highlights: ► An NH4-salt-based method utilizes CO2 and steelmaking slags to produce pure CaCO3. ► It was determined if its economic potential warrants moving forward. ► Despite small solvent losses, the method was found to have economical potential. ► The method has significant CO2 emissions reduction potential. ► Scaling up the reactor will allow for a more detailed design for the process. -- Abstract: One of the options that can contribute to the reduction of carbon dioxide emissions for climate change mitigation is the so-called CO2 sequestration by mineral carbonation, or CO2 mineral sequestration. Steel manufacturing could benefit from this option by utilizing its own by-products, i.e. steelmaking slags to combine with CO2. We have recently studied a method, where aqueous solution of ammonium salt (e.g. ammonium acetate, ammonium nitrate and ammonium chloride) is used to extract calcium selectively from the steel converter slag, followed by precipitation of pure calcium carbonate by bubbling CO2 through the produced solution. The ammonium salt solution is recovered and re-used. The purpose of this research was to determine if the economic potential of the method warrants moving forward to large-scale application. Despite the small solvent losses, the method was found to have economical potential. In addition, it has significant CO2 emission reduction potential as well. Scaling up the reactor from the small laboratory scale will allow more detailed design for the process to be made followed by a full economical evaluation including all of the important operational and capital investment costs.

  9. Assessment of errors in Precipitable Water data derived from Global Navigation Satellite System observations

    Hordyniec, Pawel; Bosy, Jaroslaw; Rohm, Witold

    2015-07-01

    Among the new remote sensing techniques, one of the most promising is a GNSS meteorology, which provides continuous remote monitoring of the troposphere water vapor in all weather conditions with high temporal and spatial resolution. The Continuously Operating Reference Station (CORS) network and available meteorological instrumentation and models were scrutinized (we based our analysis on ASG-EUPOS network in Poland) as a troposphere water vapor retrieval system. This paper shows rigorous mathematical derivation of Precipitable Water errors based on uncertainties propagation method using all available data source quality measures (meteorological sensors and models precisions, ZTD estimation error, interpolation discrepancies, and ZWD to PW conversion inaccuracies). We analyze both random and systematic errors introduced by indirect measurements and interpolation procedures, hence estimate the PW system integrity capabilities. The results for PW show that the systematic errors can be under half-millimeter level as long as pressure and temperature are measured at the observation site. In other case, i.e. no direct observations, numerical weather model fields (we used in this study Coupled Ocean Atmospheric Mesoscale Prediction System) serves as the most accurate source of data. Investigated empirical pressure and temperature models, such as GPT2, GPT, UNB3m and Berg introduced into WV retrieval system, combined bias and random errors exceeding PW standard level of accuracy (3 mm according to E-GVAP report). We also found that the pressure interpolation procedure is introducing over 0.5 hPa bias and 1 hPa standard deviation into the system (important in Zenith Total Delay reduction) and hence has negative impact on the WV estimation quality.

  10. An assessment of the isotopic (2H/18O) integrity of water samples collected and stored by unattended precipitation totalizers

    Terzer, Stefan; Wassenaar, Leonard I.; Douence, Cedric; Araguas-Araguas, Luis

    2016-04-01

    The IAEA-WMO Global Network of Isotopes in Precipitation (GNIP) provides worldwide δ18O and δ2H data for numerous hydrological and climatological studies. The traditional GNIP sample collection method relies on weather station operators to accumulate precipitation obtained from manual rain gauges. Over the past decades, widespread weather station automatization resulted in the increased use of unattended precipitation totalizers that accumulate and store the rainwater in the field for up to one month. Several low-tech measures were adopted to prevent in situ secondary evaporative isotopic enrichment (SEE) of totalized water samples (i.e. disequilibrium isotopic fractionation after precipitation is stored in the collection device). These include: (a) adding a 0.5-1 cm floating layer of paraffin oil to the totalizer bottle, (b) using an intake tube leading from the collection funnel and submerged to the bottom of the totalizer bottle, or (c) placing a table tennis ball in the funnel aiming to reduce evaporation of the collected water from the receiving bottle to the atmosphere. We assessed the isotopic integrity of stored rainwater samples for three totalizers under controlled settings: each aforementioned totalizer was filled with a 100 or 500 mL of isotopically known water and installed in the field with the intake funnels sheltered to prevent rainwater collection. Potential evapotranspiration (PET) was obtained from on-site meteorological recordings. Stored evaporative loss from each totalizer was evaluated on a monthly basis; gravimetrically and by analysing δ18O and δ2H of the stored water, for a period of 6 months and a cumulative PET of ˜500 mm. The gravimetric and isotope results revealed that for smaller water volumes (100 ml, corresponding to ca. 5 mm of monthly precipitation), negligible isotope enrichment (δ18O) was observed in the paraffin-oil based totalizer, whereas unacceptable evaporative isotope effects were observed for the ball

  11. 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.

    Tang, Sheng; Lee, Hian Kee

    2013-08-01

    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. PMID:23855757

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

    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. PMID:27311588

  13. Assessment of NDVI, land surface temperature and precipitation anomalies for drought monitoring in Bayankhongor province, Mongolia

    Guerreiro, Joana Ferreira

    2015-01-01

    During the last decade Mongolia’s region was characterized by a rapid increase of both severity and frequency of drought events, leading to pasture reduction. Drought monitoring and assessment plays an important role in the region’s early warning systems as a way to mitigate the negative impacts in social, economic and environmental sectors. Nowadays it is possible to access information related to the hydrologic cycle through remote sensing, which provides a continuous monitoring of variables...

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

    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. PMID:27040191

  15. Assessment of a method for measuring serum thyroxine by radioimmunoassay, with use of polyethylene glycol precipitation

    We assessed the efficacy of a new thyroxine radioimmunoassay kit (Abbott) in which polyethylene glycol is used to separate bound from free hormone. Mean serum thyroxine was 88 +- 15 (+-SD) μg/liter for 96 normal persons. Results for hypothyroid and hyperthyroid persons were clearly separated from those for normal individuals. Women taking oral contraceptive preparations showed variable increases in their serum thyroxine values. The coefficient of variation ranged from 1 to 3% within assay and from 5.4 to 11% among different assays. Excellent parallelism was demonstrated between thyroxine values estimated by this method and those obtained either by competitive protein binding or by a separate radioimmunoassay for the hormone

  16. A simplified approach of drought risk assessment in Poyang Lake basin using real-time precipitation and multi-source remote sensing data

    He, Haixia

    2015-12-01

    Drought risk assessment is critical to drought early-warning and drought relief decision making. Drought risk assessment is defined as the assessment on both probability and degree of damage caused by drought. This study presents a methodology for risk analysis and assessment of drought disaster t in the Poyang Lake Basin, China based on Geographical Information Systems (GIS).The main objectives of the present study are to: (1) Study the relationships among the precipitation, the water area and NDVI. (2) Assess the degree of drought disaster risk in the Poyang Lake Basin by using a method of quantitative risk analysis. The methodology employed in this study can be applied to the drought of the other area.The study introduced a new simplified approach of drought risk assessment using real-time precipitation and multi-source remote sensing data. The following conclusions are presented on the basis of study.(1)The regression shows a high level of correlation among the precipitation, drought and water area. (2)Short-time series of water area play an important role in determining if there is a drought or not or what is the degree of the drought. Further investigations are required in order to improve the precision. This can be reached by investing the relationship between the precipitation and the vegetation cover.

  17. Assessment of the Acid Rain Mountain Mesoscale Model (ARM3). Section 2

    The Acid Rain Mountain Mesoscale Model (ARM3) was developed for the Rocky Mountain region and consists of two main components: a mesoscale meteorological model and a Lagrangian acid deposition/air quality model. A study was conducted to apply ARM3 to northern Alberta and Saskatchewan and to estimate deposition resulting from the region's oil sands operations. Results of ARM3 performance are compared to those from an earlier simulation for the same region carried out using the RELMAP (REgional Lagrangian Model of Air Pollution) model. ARM3 results differed significantly from observations and from RELMAP results. ARM3 predicted that a maximum annual mean ground-level SO2 concentration of 6.0 μg/m3 occurred near the Whitecourt area while RELMAP indicated a maximum of 1.2 μg/m3 to the southeast of the source region near Fort McMurray. Since topographical effects are not included in the RELMAP model, the disagreement between ARM3 and RELMAP may be attributed to topographically induced air flow. Possible coding errors in ARM3 and inappropriate model default parameters used in the study area may also account for some of the discrepancies. Differences between ARM3 and observations may be due to limited emission sources, exclusion of background and lateral boundary flux of pollutants, lack of weather and precipitation coverage, and difficulties in interpreting precipitation quality data. Considerable computational time and storage were required by ARM3 simulations. The model is not suitable for impact assessments at large downwind distances. However, for single sources, or for impacts of future economic developments in the foothills areas, ARM3 could be useful. 15 refs., 12 figs., 5 tabs

  18. Evaporation-precipitation variability over Indian Ocean and its assessment in NCEP Climate Forecast System (CFSv2)

    Pokhrel, Samir; Parekh, Anant; Saha, Subodh Kumar; Dhakate, Ashish; Chaudhari, Hemantkumar S. [Indian Institute of Tropical Meteorology, Pune (India); Rahaman, Hasibur [Indian National Centre for Ocean Information Services, Hyderabad (India); Gairola, Rakesh Mohan [Space Applications Centre, ISRO, Ahmedabad (India)

    2012-11-15

    An attempt has been made to explore all the facets of Evaporation-Precipitation (E-P) distribution and variability over the Indian Ocean (IO) basin using Objectively Analyzed air-sea Fluxes (OAFlux) data and subsequently a thorough assessment of the latest version of National Centers for Environment Prediction (NCEP) Climate Forecast System (CFS) version-2 is done. This study primarily focuses on two fundamental issues, first, the core issue of pervasive cold SST bias in the CFS simulation in the context of moisture flux exchange between the atmosphere and the ocean and second, the fidelity of the model in simulating mean and variability of E-P and its elemental components associated with the climatic anomalies occurring over the Indian and the Pacific ocean basin. Valuation of evaporation and precipitation, the two integral component of E-P, along with the similar details of wind speed, air-sea humidity difference ({Delta}Q) and Sea Surface Temperature (SST) are performed. CFS simulation is vitiated by the presence of basin wide systematic positive bias in evaporation, {Delta}Q and similar negative bias in wind speed and SST. Bifurcation of the evaporation bias into its components reveals that bias in air humidity (Q{sub a}) is basically responsible for the presence of pervasive positive evaporation bias. The regions where CFS does not adhere to the observed wind-evaporation and Q{sub a} -evaporation relation was found to lie over the northern Arabian Sea (AS), the western Bay of Bengal (BoB) and the western Equatorial IO. Evaporation bias is found to control a significant quantum of cold SST bias over most of the basin owing to its intimate association with SST in a coupled feedback system. This area is stretched over the almost entire north IO, north of 15 {sup circle} S excluding a small equatorial strip, where the evaporation bias may essentially explain 20-100 % of cold SST bias. This percentage is maximum over the western IO, central AS and BoB. The CFS

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

    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. Spatio-temporal assessment of WRF, TRMM and in situ precipitation data in a tropical mountain environment (Cordillera Blanca, Peru

    L. Mourre

    2015-07-01

    Full Text Available The estimation of precipitation over the broad range of scales of interest for climatologists, meteorologists and hydrologists is challenging in high altitudes of tropical regions, where the spatial variability of precipitation is important while in situ measurements remain scarce largely due to operational constraints. Three different types of rainfall products – ground based, satellite derived, RCM outputs – are compared here during the hydrological year 2012/13 in order to retrieve rainfall patterns at time scales ranging from sub-daily to annual over a watershed of approximately 10 000 km2 in Peru. It is a high altitude catchment, located in the region of the Cordillera Blanca, with 41 % of its area above 4000 m a.s.l. and 340 km2 glaciated. Daily in situ data are interpolated using a kriging with external drift (KED algorithm; the satellite product is TRMM 3B42, which incorporates monthly gauge data; RCM outputs are obtained from WRF run with a Thompson microphysical scheme at three nested resolutions: 27, 9 and 3 km. The performances of each product are assessed from a double perspective. A local comparison with gauge data is first carried out when relevant (diurnal and seasonal cycles, statistics of rainfall occurrence; then the ability of each product to reproduce some well-known spatial features of rain fields at various time scales (from annual down to daily is analysed. WRF simulations largely overestimate the annual totals, especially at low spatial resolution, while reproducing correctly the diurnal cycle and locating the spots of heavy rainfall more realistically than either the ground-based KED or the TRMM products. The main weakness of the KED data is the production of annual rainfall maxima over the summit rather than on the slopes, induced by a lack of in situ data above 3800 m a.s.l. One main limitation of the TRMM product is its poor performance over ice-covered areas because ice on the ground behaves in a similar way as

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

    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.

  2. Acid rain and the NAPAP study

    This article reports on preliminary state of science and technology reports on acidic deposition released by the National Acid Precipitation Assessment Program. These are part of the integrated assessment of acidic deposition and related air pollutants to be released at a later date. SO2 and NOx emissions and effects are discussed

  3. Zinc and nickel removal in limestone based treatment of acid mine drainage: The relative role of adsorption and co-precipitation

    Highlights: • Limestone treatment of mining impacted water was simulated in batch reactors. • Zinc and nickel removals were quantified/characterized with a sequential extraction. • Removals were described with a surface complexation and a surface precipitation model. • Extraction/modeling results imply mechanisms beyond adsorption dominate metal removal. - Abstract: Mining influenced water may contain high metal and sulfate loads, and have low pH (acid mine drainage). Removal of these metals prior to environmental discharge is critical to maintain ecosystem vitality. Limestone based passive treatment systems are commonly used for pH neutralization. The same conditions that lead to pH neutralization may also remove a substantial amount of metals from solution, but the connection between treatment conditions and metal removal are not well understood. In this study, zinc and nickel removals are quantified in batch reactor simulated limestone treatment of acid mine drainage. The resulting solid phase is characterized with a sequential extraction procedure, and the removals are interpreted using surface complexation and surface precipitation models. Zinc and nickel removals are closely linked to the initial iron concentration in the mine water, but are also affected by pH, alkalinity, calcium and sulfate concentrations. The surface complexation model was based on literature descriptions of hydrous ferric oxide. In order to obtain a sufficient fit to the data, the surface site density was increased to an unrealistically high value. Uptake data was also fit to an existing surface precipitation model. The values used are similar to those found in previous studies. Both models indicate that adsorption is not the dominant removal process in the treatment system. Using adsorption only models will generally underpredict metal removals within limestone based treatment systems

  4. Precipitation and floodiness

    Stephens, E.; Day, J. J.; Pappenberger, F.; Cloke, H.

    2015-12-01

    There are a number of factors that lead to nonlinearity between precipitation anomalies and flood hazard; this nonlinearity is a pertinent issue for applications that use a precipitation forecast as a proxy for imminent flood hazard. We assessed the degree of this nonlinearity for the first time using a recently developed global-scale hydrological model driven by the ERA-Interim/Land precipitation reanalysis (1980-2010). We introduced new indices to assess large-scale flood hazard, or floodiness, and quantified the link between monthly precipitation, river discharge, and floodiness anomalies at the global and regional scales. The results show that monthly floodiness is not well correlated with precipitation, therefore demonstrating the value of hydrometeorological systems for providing floodiness forecasts for decision-makers. A method is described for forecasting floodiness using the Global Flood Awareness System, building a climatology of regional floodiness from which to forecast floodiness anomalies out to 2 weeks.

  5. THE ASSESSMENT OF ATMOSPHERIC DROUGHT DURING VEGETATION SEASON (ACCORDING TO STANDARDIZED PRECIPITATION INDEX SPI IN CENTRAL-EASTERN POLAND

    Elżbieta Radzka

    2014-12-01

    Full Text Available The paper presents an assessment of atmospheric drought during vegetation season defined on the basis of standardized precipitation index (SPI. The data used in this paper come from nine IMWM stations from central-eastern region of Poland, and they were registered in 1971–2005. The frequency of occurrence of vegetation season’s months was determined in particular drought classes. Spatial distribution of SPI index values was shown in all of the vegetation season’s months on the area examined. The direction and significance of values changes tendency of the analyzed index during the vegetation season were also defined. It was noticed that extreme droughts appeared four times less frequently than the normal months. Very dry months were noted most frequently in September while moderately dry – in August. The analysis of the frequency of spatial distribution of particular drought classes showed that extreme dry and very dry months occurred most frequently in western part of the area examined, while the moderately dry months also in south-eastern part. On the basis of the linear trend analysis it can be said that the SPI index values were slightly decreasing year by year.

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

    T. Yao

    2010-06-01

    Full Text Available Meteorological observations over the Tibetan Plateau are scarce, and precipitation estimations over this remote region are difficult. Numerical weather prediction models can be used to retrieve precipitation fields at a higher spatial and temporal resolution than the commonly used gridded precipitation products. In this paper, the Weather Research and Forecasting (WRF model capacity in retrieving rain- and snowfall during a single event is evaluated. The simulated event is the tropical cyclone RASHMI (22–28 October 2008. The simulations are conducted with three nested domains, with a mesh size of 30, 10, and 2 km. The output of the model in each resolution is compared to the Tropical Rainfall Measuring Mission (TRMM dataset for precipitation and to the Moderate Resolution Imaging Spectroradiometer (MODIS dataset for snow. TRMM and WRF precipitation products are then compared to ground based measurements: both datasets agree on the spatial repartition of precipitation, but differ on the retrieval of strong precipitation events. The results suggest an overall improvement from WRF over TRMM with respect to ground based measurements. In a second part, various physical parameterizations schemes of the model are compared. Their impact on WRF precipitation output is small, this suggests that model errors during the event may have other causes.

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

    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...

  8. Effects of precipitation variation on severe acid rain in southern China%降水变化对中国南方强酸雨分布的影响

    谢志清; 杜银; 曾燕; 李亚春; 严明良; 焦圣明

    2009-01-01

    Acid rain has been recognized as a serious environmental problem in China since the 1980s, but little is known about the effects of the climatic change in regional precipitation on the temporal and spatial variability of severe acid rain. We present the effects of the re-gional precipitation trend change on the area and intensity of severe acid rain in southern China, and the spatio-temporal distribution characteristics of SO2 and NO2 concentrations are analyzed on the basis of SO2 and NO2 column concentration data. The results are as follows. (1) The emission levels of SO2 and NO2 have reached or passed the precipitation scavenging capacity in parts of southern China owing to the emission totals of SO2 and NO2 increasing from 1993 to 2004. (2) Notable changes in the proportion of cities subject to severe acid rain occurred mainly in the south of the middle-lower reaches of the Yangtze River during 1993-2004. With an abrupt change in 1999, the severe acid rain regions were mainly located in central and western China during 1993-1999 and moved obviously eastward to the south of the lower-middle reaches of the Yangtze River with the proportion of cities subject to se-vere acid rain increasing significantly from 2000 to 2004. (3) The spatial distribution and variation in the seasonal precipitation change rate of more than 10 mm/10a are similar to those of severe acid rain in southern China. An abrupt change in 1999 is seen for winter and summer precipitation, the same as for the proportion of cities subject to severe acid rain in southern China. The significant increase in summer storm precipitation from 1991 to 1999 mitigated the annual precipitation acidity in the south of the Yangtze River and reduced the area of severe acid rainfall. On the other hand, the decrease in storm rainfall in summer ex-panded the area of severe acid rainfall in the south of the Yangtze River in 2000-2006. Therefore, the change in seasonal precipitation is an important factor in the

  9. 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

    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)

  10. Road-deposited sediment, soil and precipitation (RDS) in Bratislava, Slovakia. Compositional and spatial assessment of contamination

    Krcmova, Katrina; Cveckova, Veronika; Rapant, Stanislav [Geological Survey of the Slovak Republic, Bratislava (Slovakia); Robertson, Davina [Manchester Metropolitan Univ. (United Kingdom). Dept. of Environmental and Geographical Sciences

    2009-08-15

    Background, aim and scope: The urban environment in Bratislava is, in association with rapid urbanisation and industrialisation, significantly influenced by several potential sources of pollution, including automobile exhaust and industry emissions. Urban road-deposited sediments contain many potentially toxic elements such as Pb, Cr, Cu, Zn and also Fe at concentrations much higher than in soil. In this study, the chemical composition and spatial variability of road-deposited sediments in urban area of Bratislava were assessed for the elements As, Cd, Cr, Cu, Hg, Ni, Pb, Fe and Mn. Additional evaluation of archive data for soil, snow and atmospheric dust was undertaken to provide an integrated view on urban environment contamination. Materials and methods: Urban road-deposited sediments (RDS) were collected during summer 2003 and 2004 mainly from major city crossroads. RDS samples were analysed for total metal content, pseudo-total metal content (HNO{sub 3} digestion) and by a sequential extraction method, grain fraction composition and mineralogical composition (X-ray analysis). Metal concentrations in soil and snow samples from urban and non urban city area were compared. Results and discussion: The highest concentrations for all metals were found in the finest RDS fraction (<0.125 mm). Whilst in the fraction <1 mm mean concentrations of Cr, Cu and Pb reached 55.2, 143.8 and 34.4 mg kg{sup -1}, respectively, for the fraction <0.125 mm, markedly higher contents of these elements were documented at the level of 86.8, 218.4 and 63.1 mg kg{sup -1}, respectively. The soil contents of potentially toxic risk elements in the urban area including As, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn were higher than in the non-urban area (except for Cd with similar contents). This distribution pattern of evaluated chemicals in urban and non-urban area is more evident in the case of winter precipitation (snow). The snow concentrations of As, Cr, Cu, Fe, Mn, Pb and Zn in the urban area

  11. Mesocosm studies to assess acidity removal from acidic mine lakes through controlled eutrophication

    Flooded lignite pits (Tagebaurestseen) in Lusatia, Germany, are acidic (pH 2.5-4) with high concentrations of iron. Mesocosms (total volume 20 l) were set up with water and sediment from a Tagebaurestsee to assess the effects of phosphate and organic amendments under natural light and low temperature. Chemical and biological parameters were observed over a 9-month period. Phosphate rock addition resulted in sustained reduction in acidity in the water column and induced the growth of Chlamydomonas spp. (Chlorophyceae) near the water surface and Lepocinclis teres (Euglenophyceae) in a band above the sediment. Addition of potatoes to mesocosms resulted in the generation of near-anoxic conditions above the sediment, and phosphorus, ammonium and carbon (organic and inorganic) were released as the potatoes decomposed. A pH > 6 was attained with 5.1 g (dry weight) of potatoes and pH > 8 with 34 g (dry weight). In both mesocosms, more than 90% of total acidity was removed

  12. Mesocosm studies to assess acidity removal from acidic mine lakes through controlled eutrophication

    Fyson, A.; Nixdorf, B.; Kalin, M.; Steinberg, C.E.W. [Institute of Freshwater Ecology and Inland Fisheries, Berlin (Germany)

    1998-06-30

    Flooded lignite pits (Tagebaurestseen) in Lusatia, Germany, are acidic (pH 2.5-4) with high concentrations of iron. Mesocosms (total volume 20 l) were set up with water and sediment from a Tagebaurestsee to assess the effects of phosphate and organic amendments under natural light and low temperature. Chemical and biological parameters were observed over a 9-month period. Phosphate rock addition resulted in sustained reduction in acidity in the water column and induced the growth of Chlamydomonas spp. (Chlorophyceae) near the water surface and Lepocinclis teres (Euglenophyceae) in a band above the sediment. Addition of potatoes to mesocosms resulted in the generation of near-anoxic conditions above the sediment, and phosphorus, ammonium and carbon (organic and inorganic) were released as the potatoes decomposed. A pH {gt} 6 was attained with 5.1 g (dry weight) of potatoes and pH {gt} 8 with 34 g (dry weight). In both mesocosms, more than 90% of total acidity was removed.

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

    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.

  14. Peracetic acid for secondary effluent disinfection: a comprehensive performance assessment.

    Antonelli, M; Turolla, A; Mezzanotte, V; Nurizzo, C

    2013-01-01

    The paper is a review of previous research on secondary effluent disinfection by peracetic acid (PAA) integrated with new data about the effect of a preliminary flash-mixing step. The process was studied at bench and pilot scale to assess its performance for discharge in surface water and agricultural reuse (target microorganisms: Escherichia coli and faecal coliform bacteria). The purposes of the research were: (1) determining PAA decay and disinfection kinetics as a function of operating parameters, (2) evaluating PAA suitability as a disinfectant, (3) assessing long-term disinfection efficiency, (4) investigating disinfected effluent biological toxicity on some aquatic indicator organisms (Vibrio fischeri, Daphnia magna and Selenastrum capricornutum), (5) comparing PAA with conventional disinfectants (sodium hypochlorite, UV irradiation). PAA disinfection was capable of complying with Italian regulations on reuse (10 CFU/100 mL for E. coli) and was competitive with benchmarks. No regrowth phenomena were observed, as long as needed for agricultural reuse (29 h after disinfection), even at negligible concentrations of residual disinfectant. The toxic effect of PAA on the aquatic environment was due to the residual disinfectant in the water, rather than to chemical modification of the effluent. PMID:24355852

  15. Assessment of temperature and precipitation over Mediterranean Area and Black Sea with non hydrostatic high resolution regional climate model

    Mercogliano, P.; Montesarchio, M.; Zollo, A.; Bucchignani, E.

    2012-12-01

    public health risks. A simulation covering the period 1971-2000 and driven by ERA40 reanalysis has been performed, in order to assess the capability of the model to reproduce the present climate, with "perfect boundary conditions". A comparison, in terms of 2-metre temperature and precipitation, with EOBS dataset will be shown and discussed, in order to analyze the capabilities in simulating the main features of the observed climate over a wide area, at high spatial resolution. Then, a comparison between the results of COSMO-CLM driven by the global model CMCC-MED (whose atmospheric component is ECHAM5) and by ERA40 will be provided for a characterization of the errors induced by the global model. Finally, climate projections on the examined area for the XXI century, considering the RCP4.5 emission scenario for the future, will be provided. In this work a special emphasis will be issued to the analysis of the capability to reproduce not only the average climate patterns but also extremes of the present and future climate, in terms of temperature, precipitation and wind.

  16. Production and functional evaluation of a protein concentrate from giant squid (Dosidicus gigas) by acid dissolution and isoelectric precipitation.

    Cortés-Ruiz, Juan A; Pacheco-Aguilar, Ramón; Elena Lugo-Sánchez, M; Gisela Carvallo-Ruiz, M; García-Sánchez, Guillermina

    2008-09-15

    A protein concentrate from giant squid (Dosidicus gigas) was produced under acidic conditions and its functional-technological capability evaluated in terms of its gel-forming ability, water holding capacity and colour attributes. Technological functionality of the concentrate was compared with that of squid muscle and a neutral concentrate. Protein-protein aggregates insoluble at high ionic strength (I=0.5M), were detected in the acidic concentrate as result of processing with no preclusion of its gel-forming ability during the sol-to-gel thermal transition. Even though washing under acidic condition promoted autolysis of the myosin heavy chain, the acidic concentrate displayed an outstanding ability to gel giving samples with a gel strength of 455 and 1160gcm at 75% and 90% compression respectively, and an AA folding test grade indicative of high gel strength, elasticity, and cohesiveness. The process proved to be a good alternative for obtaining a functional protein concentrate from giant squid muscle. PMID:26049243

  17. Assessment of uncertainties in the response of the African monsoon precipitation to land use change simulated by a regional model

    S. Hagos; Leung, LR; Y. Xue; Boone, A.; Sales, F.; Neupane, N.; Huang, M; Yoon, JH

    2014-01-01

    Land use and land cover (LULC) over Africa have changed substantially over the last 60 years and this change has been proposed to affect monsoon circulation and precipitation. This study examines the uncertainties of model simulated response in the African monsoon system and Sahel precipitation due to LULC change using a set of regional model simulations with different combinations of land surface and cumulus parameterization schemes. Although the magnitude of the response covers a broad rang...

  18. Clustering of heterogeneous precipitation fields for the assessment and possible improvement of lumped neural network models for streamflow forecasts

    N. Lauzon

    2006-01-01

    Full Text Available This work addresses the issue of better considering the heterogeneity of precipitation fields within lumped rainfall-runoff models where only areal mean precipitation is usually used as an input. A method using a Kohonen neural network is proposed for the clustering of precipitation fields. The evaluation and improvement of the performance of a lumped rainfall-runoff model for one-day ahead predictions is then established based on this clustering. Multilayer perceptron neural networks are employed as lumped rainfall-runoff models. The Bas-en-Basset watershed in France, which is equipped with 23 rain gauges with data for a 21-year period, is employed as the application case. The results demonstrate the relevance of the proposed clustering method, which produces groups of precipitation fields that are in agreement with the global climatological features affecting the region, as well as with the topographic constraints of the watershed (i.e., orography. The strengths and weaknesses of the rainfall-runoff models are highlighted by the analysis of their performance vis-à-vis the clustering of precipitation fields. The results also show the capability of multilayer perceptron neural networks to account for the heterogeneity of precipitation, even when built as lumped rainfall-runoff models.

  19. Clustering of heterogeneous precipitation fields for the assessment and possible improvement of lumped neural network models for streamflow forecasts

    Lauzon, N.; Anctil, F.; Baxter, C. W.

    2006-07-01

    This work addresses the issue of better considering the heterogeneity of precipitation fields within lumped rainfall-runoff models where only areal mean precipitation is usually used as an input. A method using a Kohonen neural network is proposed for the clustering of precipitation fields. The evaluation and improvement of the performance of a lumped rainfall-runoff model for one-day ahead predictions is then established based on this clustering. Multilayer perceptron neural networks are employed as lumped rainfall-runoff models. The Bas-en-Basset watershed in France, which is equipped with 23 rain gauges with data for a 21-year period, is employed as the application case. The results demonstrate the relevance of the proposed clustering method, which produces groups of precipitation fields that are in agreement with the global climatological features affecting the region, as well as with the topographic constraints of the watershed (i.e., orography). The strengths and weaknesses of the rainfall-runoff models are highlighted by the analysis of their performance vis-à-vis the clustering of precipitation fields. The results also show the capability of multilayer perceptron neural networks to account for the heterogeneity of precipitation, even when built as lumped rainfall-runoff models.

  20. Assessment of folic acid and DNA damage in cleft lip and cleft palate

    Sivakumar Brooklyin; Rashmoni Jana; Singaravelu Aravinthan; Bethou Adhisivam; Parkash Chand

    2014-01-01

    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...

  1. Distribution of trichloroacetic acid precipitated radioactivity in rabbits after intravenous injection of 125I-labelled single-chain human recombinant urokinase-type plasminogen activator

    Objective: To study tissue distribution profiles of trichloroacetic acid (TCA) precipitated radioactivity in rabbits following intravenous injection of 125I-labelled single-chain human recombinant urokinase-type plasminogen activator (125I-rh-sc-uPA). Methods: 125I-rh-su-uPA was prepared by Iodogen method and was purified by Saphacryl HR S-200. The radio-chemical purity was measured by reverse phase high performance liquid chromatography (RP-HPLC). Biological activity of labelled protein was measured by thrombolytic activity on fibrin plate. Results: The identification of 125I-rh-sc-uPA revealed that it was a 94.4% radio-chemically purified thrombolytic active protein. The AUC of radioactivity gradients in tissues and other specimens were as follows: kidney>urine>plasma>liver>spleen>adrenal gland>bone marrow>heart>urinary bladder>lungs>gonad>small intestinal wall>fat>lymph node>gall bladder>thymus gland>intestinal content>muscle>brain>feces in colon. Conclusion: The highest TCA precipitated radioactivity was found in plasma following I.V. of 125I-rh-u-PA, which might be favorable for the drug action. The main excretion route was urinary system

  2. Isolation of an acidic protein from cholesterol gallstones, which inhibits the precipitation of calcium carbonate in vitro.

    Shimizu, S.; Sabsay, B; Veis, A.; Ostrow, J D; Rege, R V; Dawes, L G

    1989-01-01

    In seeking to identify nucleating/antinucleating proteins involved in the pathogenesis of cholesterol gallstones, a major acidic protein was isolated from each of 13 samples of cholesterol gallstones. After the stones were extracted with methyl t-butyl ether to remove cholesterol, and methanol to remove bile salts and other lipids, they were demineralized with EDTA. The extracts were desalted with Sephadex-G25, and the proteins separated by PAGE. A protein was isolated, of molecular weight be...

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

    Wengang Li; Xiuhua Zhao; Xiaoli Sun; Yuangang Zu; Ying Liu; Yunlong Ge

    2016-01-01

    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: TC...

  4. Ultrasonic assessment of shape index and number of graphite precipitations in spheroidal cast iron manufactured in the foundry METAL-ODLEW Sp.J.

    W. Orłowicz; M. Tupaj; M. Mróz; E. Guzik; J. Nykiel; A Zając; B. Piotrowski

    2009-01-01

    This study presents the results of testing the shape index, number of graphite precipitations, and longitudinal ultrasound wave velocity with wedge castings used for production of samples for the assessment of mechanical characteristics. To differentiate values of the parameters, the castings were made at the same time as the production castings. The data obtained were used to establish the relationship between the ultrasonic wave velocity cL, the shape index SS and the number of graphite pre...

  5. Assessment of Precipitation and Drought Variability in Weihe River of China Over the Period 1960-2010

    Chang, J.; Wang, Y.

    2015-12-01

    The amount and distribution of precipitation play crucial roles in the occurrence of drought in the Weihe River Basin (WRB) of China. Using the precipitation data (1960-2010) of 21 meteorological stations, the spatial and temporal characteristics of droughts were examined by using theory of runs and the Standardized Precipitation Index on 3-month, 6-month and 12-month time scales. The results showed that the main drought type was moderate drought, and drought occurred frequently on July and October. During the last 50 years, the drought intensity and frequency were the biggest in 1991-2000. According to the SPI-3, the risk of spring and fall drought increased gradually, which could impact on agriculture and water supply. The trend of SPI values over the time period was calculated and analyzed, showing of increasing dryness throughout the basin, and the north and northwest zones of WRB were most likely to suffer from drought. Also, compared with the east, the drought severity and drought duration in the northwest was more serious. It was also observed that there was strong relation between precipitation distribution and drought zones in the basin, and the drought conditions changed continuously with seasons depending upon precipitation amount and its spatial distribution.

  6. Sequestration of U(VI) from aqueous solutions using precipitate ion imprinted polymers endowed with oleic acid functionalized magnetite

    The use of a polymeric sorbent material embedded with oleic acid coated magnetic particles as selective sorbents for the removal of U(VI) ions from industrial waste effluents was studied. In the presence of other competing ions [Th(IV) and Ni(II)], U(VI) was preferentially adsorbed. Inclusion of nano-magnetic particles in the polymer matrix aided the separation of the sorbents from aqueous solutions by application of external magnetic field. High recoveries indicated that the sorbent is suitable for application in contaminated water. (author)

  7. Method of precipitating uranium peroxide

    The uranium dissolved as uranyl tricarbonate ion in an aqueous alkaline solution is precipitated out as uranium peroxide. The precipitation is carried out by acidifying a portion of the aqueous alkaline solution with excess sulfuric acid to convert the uranyl tricarbonate ion to the uranyl ion and carbon dioxide. This is followed by the addition of hydrogen peroxide to the acidified solution to convert the uranyl ion to uranium peroxide precipitate, producing additional acid. Concurrently, a different portion of the aqueous alkaline uranyl tricarbonate solution is added to the precipitating solution to elevate the pH to an acidic range which is optimum for effective reaction to uranium peroxide and for its precipitation

  8. Assessing the Effects of Spatial Resolution on Regional Climate Model Simulated Summer Temperature and Precipitation in China: A Case Study

    Xin-Min Zeng

    2016-01-01

    Full Text Available The regional climate model, RegCM3, is used to simulate the 2004 summer surface air temperature (SAT and precipitation at different horizontal (i.e., 30, 60, and 90 km and vertical resolutions (i.e., 14, 18, and 23 layers. Results showed that increasing resolution evidently changes simulated SATs with regional characteristics. For example, simulated SATs are apparently better produced when horizontal resolution increases from 60 to 30 km under the 23 layers. Meanwhile, the SATs over the entire area are more sensitive to vertical resolution than horizontal resolution. The subareas present higher sensitivities than the total area, with larger horizontal resolution effects than those of vertical resolution. For precipitation, increasing resolution shows higher impact compared to SAT, with higher sensitivity induced by vertical resolution than by horizontal resolution, especially in rainy South China. The best SAT/precipitation can be produced only when the horizontal and vertical resolutions are reasonably configured. This indicates that different resolutions lead to different atmospheric thermodynamic states. Because of the dry climate and low soil heat capacity in Northern China, resolution changes easily modify surface energy fluxes, hence the SAT; due to the rainy and humid climate in South China, resolution changes likely strongly influence grid-scale structure of clouds and therefore precipitation.

  9. ROE Precipitation

    U.S. Environmental Protection Agency — This polygon dataset represents the rate of change in precipitation across the United States in terms of percent change per century. The map shows National Oceanic...

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

    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.

  11. 佛山市降水成分及酸雨污染状况分析%Analysis of Components of Precipitation and Pollution Status of Acid Rain in Foshan City

    姚镇; 梁丽红

    2012-01-01

    以“十一五”期间佛山市降水样品监测资料为基础,对佛山市大气降水的离子组成和酸雨污染状况进行了分析,结果表明:佛山市降水pH值较低,酸雨污染较为严重,降水中的主要阳离子是Ca2+和NH4+,主要阴离子为SO4^2-和NO3-,酸雨类型已从单一的硫酸型逐渐转变为硫酸和硝酸混合型。%The ion composition of atmospheric precipitation and the acid rain pollution status of Foshan are studied in this paper on the basis of monitoring data measured during the Eleventh Five Year Plan period. The results show that the pH value of precipitation is low, and the acid rain pollution status is serious; the major cations in precipitation are Ca2+ and NH4+ and the major anions are SO4^2- and NO3^2- ;the acid rain type has been gradually transformed from a single sulfate acid type into the mixed type of sulfuric acid and nitric acid.

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

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

    2016-01-01

    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 (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. PMID:27438241

  13. 碱提酸沉法提取茶叶蛋白质的研究%Extraction of Tea Protein using Alkali Extraction-acid Precipitation Method

    陆晨; 张士康; 朱科学; 王彬; 周惠明

    2011-01-01

    Extraction of tea-protein from green tea by using alkali extraction and acid precipitation was investigated. Amino acid compositions of the tea protein ware also analyzed. The results showed that the optimum extraction parameters were NaOH 0.3 mol/L, green tes/water solution (m/V) 1:25, temperature50 ℃, stirring time 1 h and extraction times twice, under which the protein extraction efficiency was 85.50%. The best pI of the tea protein was 3.0, the protein concentration precipitation rate was 67.85% and the protein content was 47.76%. The tea protein contained 18 kinds of amino acid, in which essential amino acids were 40.68%. Amino acid score of tea protein was higher than soybean protein and close to those of breast milk und milk, which indicated that tea protein was one of high quality leaf proteins. This method is easy to operate, low-cost and highly efficient, thereby being suitable for the massive industrial production of tea protein.%以绿茶为原料,采用碱提酸沉的方法提取茶叶蛋白质,以料液比、碱液浓度、温度、时间为考查因素,研究茶叶蛋白质的最佳提取工艺条件,并对提得的茶叶蛋白质进行了氨基酸分析.结果表明:碱提酸沉法提取茶叶蛋白质的最佳工艺条件为料液比1∶25(m/V),碱液浓度03 mol/L,提取温度50℃,提取时间1 h,连续提取两次,茶叶蛋白质的提取率达到85.50%.茶叶蛋白质的最佳等电点为3.0,蛋白质沉淀率为67.85%,粗提取物中蛋白质质量分数为47.76%.氨基酸分析表明:茶叶蛋白质含有18种氨基酸,其中必需氨基酸含量占40.68%;氨基酸评分高于大豆,接近母乳和牛奶,是一种优质的叶蛋白质资源.综合考虑,此方法操作简单,生产成本低,提取效果好,适用于茶叶蛋白质的工业化生产.

  14. Assessment of Uncertainties in the Response of the African Monsoon Precipitation to Land Use Change in Regional Model Simulations

    Hagos, S. M.; Leung, L.; Xue, Y.; Boone, A. A.; Huang, M.; Yoon, J.

    2013-12-01

    Land use and land cover over Africa have changed substantially over the last sixty years and this change has been proposed to affect monsoon circulation and precipitation. This study examines the uncertainties on the effect of these changes on the African Monsoon system and Sahel precipitation using an ensemble of regional model simulations with different combinations of land surface and cumulus parameterization schemes. Although the magnitude of the response covers a broad range of values, most of the simulations show a decline in Sahel precipitation due to the expansion of pasture and croplands at the expense of trees and shrubs and an increase in surface air temperature. The relationship between the model responses to land use change and the climatologies of the control simulations is also examined. Simulations that are climatologically too dry or too wet compared to observations and reanalyses have weak response to land use change because they are in moisture or energy limited regimes respectively. The ones that lie in between and therefore land-atmosphere interactions play a more significant role have stronger response to the land use and land cover changes. Much of the change in precipitation is related to changes in circulation, particularly to the response of the intensity and latitudinal position of the African Easterly Jet, which varies with the changes in meridional surface temperature gradients. The study highlights the need for measurements of the surface fluxes across the meridional cross-section of the Sahel to evaluate models and thereby allowing human impacts such as land use change on the monsoon to be projected more realistically.

  15. Assessment of uncertainties in the response of the African monsoon precipitation to land use change simulated by a regional model

    Hagos, Samson; Leung, L. Ruby; Xue, Yongkang; Boone, Aaron; de Sales, Fernando; Neupane, Naresh; Huang, Maoyi; Yoon, Jin-Ho

    2014-11-01

    Land use and land cover (LULC) over Africa have changed substantially over the last 60 years and this change has been proposed to affect monsoon circulation and precipitation. This study examines the uncertainties of model simulated response in the African monsoon system and Sahel precipitation due to LULC change using a set of regional model simulations with different combinations of land surface and cumulus parameterization schemes. Although the magnitude of the response covers a broad range of values, most of the simulations show a decline in Sahel precipitation due to the expansion of pasture and croplands at the expense of trees and shrubs and an increase in surface air temperature. The relationship between the model responses to LULC change and the climatologists of the control simulations is also examined. Simulations that are climatologically too dry or too wet compared to observations and reanalyses have weak response to land use change because they are in moisture or energy limited regimes respectively. The ones that lie in between have stronger response to the LULC changes, showing a more significant role in land-atmosphere interactions. Much of the change in precipitation is related to changes in circulation, particularly to the response of the intensity and latitudinal position of the African Easterly Jet, which varies with the changes in meridional surface temperature gradients. The study highlights the need for measurements of the surface fluxes across the meridional cross-section of the Sahel to evaluate models and thereby allowing human impacts such as land use change on the monsoon to be projected more realistically.

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

    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

  17. Effects of calcium and ferric ions on struvite precipitation: A new assessment based on quantitative X-ray diffraction analysis.

    Yan, Hanlu; Shih, Kaimin

    2016-05-15

    The precipitation of struvite (MgNH4PO4·6H2O) from waste streams has attracted considerable attention due to its potential for recovering phosphorus for fertilization. As struvite is primarily acquired by means of precipitation and crystallization from aqueous solutions, it is important to evaluate the roles of common metal ions, particularly those that are commonly found in wastewater, in the struvite crystallization process. This study was performed to quantitatively evaluate the effects of calcium and ferric ions on struvite crystallization using the Rietveld refinement method, which is based on the analysis of X-ray diffraction data. The results indicate that both calcium and ferric ions significantly inhibit the formation of struvite crystals, and the effects vary under different pH conditions. There was a negative linear correlation between the struvite weight content in the precipitates and the Ca/Mg molar ratio in the initial solution. However, ferric ions were confirmed to be a more efficient inhibitor of struvite crystallization. Ca(2+) and Fe(3+) further modified the needle-like struvite into irregular shapes. An unambiguous and quantitative understanding of the effects of foreign ions on struvite crystallization will help to reliably improve the quality of struvite products recovered from wastewater and the control of struvite deposits in water and sludge piping systems. PMID:27016641

  18. Fungal Peptaibiotics: Assessing Potential Meteoritic Amino Acid Contamination

    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.

  19. Run-based multi-model interannual variability assessment of precipitation and temperature over Pakistan using two IPCC AR4-based AOGCMs

    Asmat, U.; Athar, H.

    2015-09-01

    The interannual variability of precipitation and temperature is derived from all runs of the Intergovernmental Panel on Climate Change (IPCC) fourth Assessment Report (AR4)-based two Atmospheric Oceanic General Circulation Model (AOGCM) simulations, over Pakistan, on an annual basis. The models are the CM2.0 and CM2.1 versions of Geophysical Fluid Dynamics Laboratory (GFDL)-based AOGCM. Simulations for a recent 22-year period (1979-2000) are validated using Climate Research Unit (CRU) and NCEP/NCAR datasets over Pakistan, for the first time. The study area of Pakistan is divided into three regions: all Pakistan, northern Pakistan, and southern Pakistan. Bias, root mean square error, one sigma standard deviation, and coefficient of variance are used as validation metrics. For all Pakistan and northern Pakistan, all three runs of GFDL-CM2.0 perform better under the above metrics, both for precipitation and temperature (except for one sigma standard deviation and coefficient of variance), whereas for southern Pakistan, third run of GFDL-CM2.1 perform better expect for the root mean square error for temperature. A mean and variance-based bias correction is applied to bias in modeled precipitation and temperature variables. This resulted in a reduced bias, except for the months of June, July, and August, when the reduction in bias is relatively lower.

  20. Catabolic fate of Streptomyces viridosporus T7A-Produced, acid precipitable polymeric lignin upon incubation with ligninolytic Streptomyces species and Phanerochaete chrysosporium

    Degradation of ground and hot-water-extracted corn stover (Zea mays) lignocellulose by Streptomyces viridosporus T7A generates a water-soluble lignin degradation intermediate termed acid-precipitable polymeric lignin (APPL). The further catabolism of T7A-APPL by S. viridosporus T7A, S. badius 252, and S. setonii75Vi2 was followed for 3 weeks. APPL catabolism by Phanerochaete chrysosporium was followed in stationary cultures in a low-nitrogen medium containing 1% (wt/vol) glucose and 0.05% (wt/vol) T7A-APPL. Metabolism of the APPL was followed by turbidometric assay (600 nm) and by direct measurement of APPL recoverable from the medium. Accumulation and disappearance of soluble low-molecular-weight products of APPL catabolism were followed by gas-liquid chromatography and by high-pressure liquid chromatography, utilizing a diode array detector. Mineralization of a [14C-lignin]APPL was also followed. The percent 14C recovered as 14CO2, 14C-APPL, 14C-labeled water-soluble products, and cell mass-associated radioactivity, were determined for each microorganism after 1 and 3 weeks of incubation in bubbler tube cultures at 370C. P. chrysosporium evolved the most 14CO2, and S. viridosporus gave the greatest decrease in recoverable 14C-APPL. The results show that S. badius was not able to significantly degrade the APPL, while the other microorganisms demonstrated various APPL-degrading abilities

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

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

    2013-01-01

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

  2. Durability improvement assessment in different high strength bacterial structural concrete grades against different types of acids

    Ramin Andalib; M Zaimi Abd Majid; A Keyvanfar; Amirreza Talaiekhozan; Mohd Warid Hussin; A Shafaghat; Rosli Mohd Zin; Chew Tin Lee; Mohammad Ali Fulazzaky; Hasrul Haidar Ismail

    2014-12-01

    This paper provides an insight into a new biotechnological method based on calcite precipitation for achieving high strength bio-concrete durability. It is very clear that mineral precipitation has the potential to enhance construction material resistance towards degradation procedures. The appropriate microbial cell concentration (30 * 105 cells/ml) was introduced onto different structural concrete grades (40, 45 and 50 MPa) by mixing water. In order to study the durability of structural concrete against aggressive agents, specimens were immersed in different types of acids solution (5% H2SO4 and HCl) to compare their effects on 60th, 90th and 120th day. In general, sulphuric acid and hydrochloric acid are known to be the most aggressive natural threats from industrial waters which can penetrate concrete to transfer the soluble calcium salts away from the cement matrix. The experimental results demonstrated that bio-concrete has less weight and strength losses when compared to the ordinary Portland cement concrete without microorganism. It was also found that maximum compressive strength and weight loss occurred during H2SO4 acid immersion as compared to HCl immersion. The density and uniformity of bio-concrete were examined using ultrasonic pulse velocity (UPV) test. Microstructure chemical analysis was also quantified by energy dispersive spectrometer (EDS) to justify the durability improvement in bacterial concrete. It was observed that less sulphur and chloride were noticed in bacterial concrete against H2SO4 and HCl, respectively in comparison to the ordinary Portland cement concrete due to calcite deposition.

  3. Precipitation Matters

    McDuffie, Thomas

    2007-01-01

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

  4. Performance assessment of a triple-frequency spaceborne cloud–precipitation radar concept using a global cloud-resolving model

    J. Leinonen

    2015-04-01

    Full Text Available Multi-frequency radars offer enhanced detection of clouds and precipitation compared to single-frequency systems, and are able to make more accurate retrievals when several frequencies are available simultaneously. An evaluation of a spaceborne three-frequency Ku/Ka/W-band radar system is presented in this study, based on modeling radar reflectivities from the results of a global cloud-resolving model with a 875 m grid spacing. To produce the reflectivities, a scattering model has been developed for each of the hydrometeor types produced by the model, as well as for melting snow. The effects of attenuation and multiple scattering on the radar signal are modeled using a radiative transfer model, while nonuniform beam filling is reproduced with spatial averaging. The combined effects of these are then quantified both globally and in five localized case studies. Two different orbital scenarios using the same radar are compared. Overall, based on the results, it is expected that the proposed radar would detect a high-quality signal in most clouds and precipitation. The main exceptions are the thinnest clouds that are below the detection threshold of the W-band channel, and at the opposite end of the scale, heavy convective rainfall where a combination of attenuation, multiple scattering and nonuniform beam filling commonly cause significant deterioration of the signal; thus, while the latter can be generally detected, the quality of the retrievals is likely to be degraded.

  5. Assessing spatio-temporal variations of precipitation-use efficiency over Tibetan grasslands using MODIS and in-situ observations

    Liu, Zhengjia; Huang, Mei

    2016-03-01

    Clarifying the spatial and temporal variations in precipitation-use efficiency (PUE) is helpful for advancing our knowledge of carbon and water cycles in Tibetan grassland ecosystems. Here we use an integrated remote sensing normalized difference vegetation index (NDVI) and in-situ above-ground net primary production (ANPP) measurements to establish an empirical exponential model to estimate spatial ANPP across the entire Tibetan Plateau. The spatial and temporal variations in PUE (the ratio of ANPP to mean annual precipitation (MAP)), as well as the relationships between PUE and other controls, were then investigated during the 2001-2012 study period. At a regional scale, PUE increased from west to east. PUE anomalies increased significantly (>0.1 g·m-2·mm-1/10 yr) in the southern areas of the Tibetan Plateau yet decreased (>0.02 g·m-2·mm-1/10 yr) in the northeastern areas. For alpine meadow, we obtained an obvious breaking point in trend of PUE against elevation gradients at 3600 m above the sea level, which showed a contrasting relationship. At the inter-annual scale, PUE anomalies were smaller in alpine steppe than in alpine meadow. The results show that PUE of Tibetan grasslands is generally high in dry years and low in wet years.

  6. Assessing amino acid racemization variability in coral intra-crystalline protein for geochronological applications

    Hendy, Erica J.; Tomiak, Peter J.; Collins, Matthew J.; Hellstrom, John; Tudhope, Alexander W.; Lough, Janice M.; Penkman, Kirsty E. H.

    2012-01-01

    Over 500 Free Amino Acid (FAA) and corresponding Total Hydrolysed Amino Acid (THAA) analyses were completed from eight independently-dated, multi-century coral cores of massive Porites sp. colonies. This dataset allows us to re-evaluate the application of amino acid racemization (AAR) for dating late Holocene coral material, 20 years after Goodfriend et al. (GCA 56 (1992), 3847) first showed AAR had promise for developing chronologies in coral cores. This re-assessment incorporates recent met...

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

    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...

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

    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.

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

    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

  10. Accuracy of sequence alignment and fold assessment using reduced amino acid alphabets.

    Melo, Francisco; Marti-Renom, Marc A

    2006-06-01

    Reduced or simplified amino acid alphabets group the 20 naturally occurring amino acids into a smaller number of representative protein residues. To date, several reduced amino acid alphabets have been proposed, which have been derived and optimized by a variety of methods. The resulting reduced amino acid alphabets have been applied to pattern recognition, generation of consensus sequences from multiple alignments, protein folding, and protein structure prediction. In this work, amino acid substitution matrices and statistical potentials were derived based on several reduced amino acid alphabets and their performance assessed in a large benchmark for the tasks of sequence alignment and fold assessment of protein structure models, using as a reference frame the standard alphabet of 20 amino acids. The results showed that a large reduction in the total number of residue types does not necessarily translate into a significant loss of discriminative power for sequence alignment and fold assessment. Therefore, some definitions of a few residue types are able to encode most of the relevant sequence/structure information that is present in the 20 standard amino acids. Based on these results, we suggest that the use of reduced amino acid alphabets may allow to increasing the accuracy of current substitution matrices and statistical potentials for the prediction of protein structure of remote homologs. PMID:16506243