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Sample records for chemical leaching reject

  1. Potencial poluidor de rejeitos carboníferos: I - Caracterização química da água de lixiviação Pollutant potencial of coal rejects: I - Chemical characterization of the leached water

    Directory of Open Access Journals (Sweden)

    Larisa Ho Bech Gaivizzo

    2002-10-01

    Full Text Available O aumento da produção carbonífera no Rio Grande do Sul para o atendimento da crescente demanda por energia tem proporcionado o acúmulo desordenado de grandes volumes de rejeitos nas áreas de mineração. Esses rejeitos afetam a qualidade da água, do ar e do solo, bem como a vegetação e a fauna, podendo representar elevado comprometimento ambiental para a região. Assim, realizou-se o presente estudo com o objetivo de avaliar a composição química da água de lixiviação proveniente de colunas de PVC em experimento envolvendo diferentes espessuras de solo aplicadas na superfície do rejeito carbonífero, solo em posições de subsuperfície e solo misturado ao rejeito. A água de lixiviação foi coletada em 1993, durante o cultivo de milho e trevo-branco, em 1995, antes e após o cultivo de aveia-preta, e em 1996, após o cultivo de milho. Os dados demonstram que o baixo pH da água de lixiviação manteve solúvel parte dos elementos provenientes da dissolução do rejeito carbonífero, refletindo-se em elevada condutividade elétrica. Os elementos S, Fe, Mn, Zn, Ni e Pb foram os que ocorreram em maiores concentrações na água de lixiviação, com potencial poluidor dos recursos hídricos.The quality of water, air, soil, vegetation and fauna have been affected by the increasing explotation of coal and consequently increasing of rejects that have been accumulated, causing adverse effects on the environment of a region in Rio Grande do Sul State, Brazil. An experiment was carried out to evaluate the chemical composition of leached water as a consequence of soil layers with different thickness disposed on PVC columns in the surface of coal rejects, in subsurface positions, and soil mixed with rejects. The leachates were collected in 1993, during (Zea mays L. corn and white clover (Trifolium repens L. growth; in 1995, before and after oat growth (Avena strigosa L.; and in 1996 after corn growth. Leached water had a high electrical

  2. Potential use of a chemical leaching reject from a kaolin industry as agricultural fertilizer Uso potencial do resíduo químico lixiviado duma indústria de caulim como adubo de terras agrícolas

    Directory of Open Access Journals (Sweden)

    Fabiana Rodrigues Ribeiro

    2007-10-01

    Full Text Available The industrial refining of kaolin involves the removal of iron oxides and hydroxides along with other impurities that cause discoloration of the final product and depreciate its commercial value, particularly undesirable if destined to the paper industry. The chemical leaching in the industrial processing requires treatments with sodium hyposulfite, metallic zinc, or sulfuric and phosphoric acids, in order to reduce, dissolve and remove ferruginous compounds. To mitigate the environmental impact, the acidic effluent from the leaching process must be neutralized, usually with calcium oxide. The resulting solid residue contains phosphorous, zinc, and calcium, among other essential nutrients for plant growth, suggesting its use as a macro and micronutrient source. Samples of such a solid industrial residue were used here to evaluate their potential as soil fertilizer in an incubation greenhouse experiment with two soil samples (clayey and medium-textured. The small pH shift generated by applying the residue to the soil was not a limiting factor for its use in agriculture. The evolution of the concentrations of exchangeable calcium, and phosphorous and zinc extractability by Mehlich-1 extractant during the incubation period confirms the potential use of this industrial residue as agricultural fertilizer.O beneficiamento industrial do caulim envolve a remoção de óxidos e hidróxidos de ferro e outras impurezas, que conferem coloração indesejável ao produto final e depreciam seu valor comercial, particularmente se destinado à indústria de papel. A lixiviação química, na linha de processamento industrial, pode ser feita com tratamentos com hipossulfito de sódio, zinco metálico e ácidos sulfúrico e fosfórico, para redução, solubilização e remoção de compostos ferruginosos. A fim de minimizar o impacto ambiental, o efluente ácido, procedente da etapa de lixiviação, deve ser inicialmente neutralizado, usualmente por óxido de c

  3. Leaching characteristics of Idaho Chemical Processing Plant calcines

    International Nuclear Information System (INIS)

    This report documents leaching studies conducted on two non-radioactive, pilot-plant calcines produced at the Idaho Chemical Processing Plant. The two pilot-plant calcines simulate radioactive calcine which may be produced in the New Waste Calcining Facility by blending high-level liquid waste and sodium-bearing liquid waste. The calcines were subjected to the Environmental Protection Agency's Extraction Procedure Toxicity Test and to a test based on the Materials Characterization Center's MCC-1 Static Leach Test. Following the protocol of these tests, leachates were obtained and analyzed for chemical composition to develop information about component mass loss and total mass loss. Surface analysis techniques were employed in an attempt to identify species that were leached from the calcines, but later precipitated during the MCC-1 tests. This report also documents leaching studies conducted on a radioactive fluorinel-sodium blend calcine produced in the New Waste Calcining Facility. This calcine was also subjected to a static leach test based on the MCC-1 test. The leachate was analyzed to develop information about total mass loss and leaching characteristics of radioactive species. 12 refs., 9 figs., 9 tabs

  4. Leaching characteristics of Idaho Chemical Processing Plant calcines

    Energy Technology Data Exchange (ETDEWEB)

    Chipman, N A

    1990-02-01

    This report documents leaching studies conducted on two non-radioactive, pilot-plant calcines produced at the Idaho Chemical Processing Plant. The two pilot-plant calcines simulate radioactive calcine which may be produced in the New Waste Calcining Facility by blending high-level liquid waste and sodium-bearing liquid waste. The calcines were subjected to the Environmental Protection Agency's Extraction Procedure Toxicity Test and to a test based on the Materials Characterization Center's MCC-1 Static Leach Test. Following the protocol of these tests, leachates were obtained and analyzed for chemical composition to develop information about component mass loss and total mass loss. Surface analysis techniques were employed in an attempt to identify species that were leached from the calcines, but later precipitated during the MCC-1 tests. This report also documents leaching studies conducted on a radioactive fluorinel-sodium blend calcine produced in the New Waste Calcining Facility. This calcine was also subjected to a static leach test based on the MCC-1 test. The leachate was analyzed to develop information about total mass loss and leaching characteristics of radioactive species. 12 refs., 9 figs., 9 tabs.

  5. Coupling between chemical degradation and mechanical behaviour of leached concrete

    International Nuclear Information System (INIS)

    This work is in the context of the long term behavior of concrete employed in radioactive waste disposal. The objective is to study the coupled chemo-mechanical modelling of concrete. In the first part of this contribution, experimental investigations are described where the effects of the calcium leaching process of concrete on its mechanical properties are highlighted. An accelerated method has been chosen to perform this leaching process by using an ammonium nitrate solution. In the second part, we present a coupled phenomenological chemo-mechanical model that represents the degradation of concrete materials. On one hand, the chemical behavior is described by the simplified calcium leaching approach of cement paste and mortar. Then a homogenization approach using the asymptotic development is presented to take into account the influence of the presence of aggregates in concrete. And on the other hand, the mechanical part of the modelling is given. Here continuum damage mechanics is used to describe the mechanical degradation of concrete. The growth of inelastic strains observed during the mechanical tests is describes by means of a plastic like model. The model is established on the basis of the thermodynamics of irreversible processes framework. The coupled nonlinear problem at hand is addressed within the context of the finite element method. Finally, numerical simulations are compared with the experimental results for validation. (author)

  6. Removal of phosphorus from iron ores by chemical leaching

    Institute of Scientific and Technical Information of China (English)

    JIN Yong-shi; JIANG Tao; YANG Yong-bin; LI Qian; LI Guang-hui; GUO Yu-feng

    2006-01-01

    Alkali-leaching and acid-leaching were proposed for the dephosphorization of Changde iron ore, which contains an average of 1.12% for phosphorus content. Sodium hydroxide, sulfuriced, hydrochloric and nitric acids were used for the preparation of leach solutions. The results show that phosphorus occurring as apatite phase could be removed by alkali-leaching, but those occurring in the iron phase could not. Sulfuric acid is the most effective among the three kinds of acid. 91.61% phosphorus removal was attained with 1% sulfuric acid after leaching for 20 min at room temperature. Iron loss during acid-leaching can be negligible, which was less than 0.25%.The pH value of solution after leaching with 1% sulfuric acid was about 0.86, which means acid would not be exhausted during the process and it could be recycled, and the recycle of sulfuric acid solution would make the dephosphorization process more economical.

  7. Computational chemical imaging for cardiovascular pathology: chemical microscopic imaging accurately determines cardiac transplant rejection.

    Directory of Open Access Journals (Sweden)

    Saumya Tiwari

    Full Text Available Rejection is a common problem after cardiac transplants leading to significant number of adverse events and deaths, particularly in the first year of transplantation. The gold standard to identify rejection is endomyocardial biopsy. This technique is complex, cumbersome and requires a lot of expertise in the correct interpretation of stained biopsy sections. Traditional histopathology cannot be used actively or quickly during cardiac interventions or surgery. Our objective was to develop a stain-less approach using an emerging technology, Fourier transform infrared (FT-IR spectroscopic imaging to identify different components of cardiac tissue by their chemical and molecular basis aided by computer recognition, rather than by visual examination using optical microscopy. We studied this technique in assessment of cardiac transplant rejection to evaluate efficacy in an example of complex cardiovascular pathology. We recorded data from human cardiac transplant patients' biopsies, used a Bayesian classification protocol and developed a visualization scheme to observe chemical differences without the need of stains or human supervision. Using receiver operating characteristic curves, we observed probabilities of detection greater than 95% for four out of five histological classes at 10% probability of false alarm at the cellular level while correctly identifying samples with the hallmarks of the immune response in all cases. The efficacy of manual examination can be significantly increased by observing the inherent biochemical changes in tissues, which enables us to achieve greater diagnostic confidence in an automated, label-free manner. We developed a computational pathology system that gives high contrast images and seems superior to traditional staining procedures. This study is a prelude to the development of real time in situ imaging systems, which can assist interventionists and surgeons actively during procedures.

  8. The performance with data processing of chemical treatment with leaching and bio-leaching

    OpenAIRE

    Agron, Alili; Krstev, Boris; Krstev, Aleksandar; Stamenov, Goran

    2015-01-01

    The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the meantime, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer program Multisimplex performances are appropriate and most acceptable and excel...

  9. The removal of mercury from solid mixed waste using chemical leaching processes

    International Nuclear Information System (INIS)

    The focus of this research was to evaluate chemical leaching as a technique to treat soils, sediments, and glass contaminated with either elemental mercury or a combination of several mercury species. Potassium iodide/iodine solutions were investigated as chemical leaching agents for contaminated soils and sediments. Clean, synthetic soil material and surrogate storm sewer sediments contaminated with mercury were treated with KI/I2 solutions. It was observed that these leaching solutions could reduce the mercury concentration in soil and sediments by 99.8%. Evaluation of selected posttreatment sediment samples revealed that leachable mercury levels in the treated solids exceeded RCRA requirements. The results of these studies suggest that KI/I2 leaching is a treatment process that can be used to remove large quantities of mercury from contaminated soils and sediments and may be the only treatment required if treatment goals are established on Hg residual concentrations in solid matrices. Fluorescent bulbs were used to simulate mercury contaminated glass mixed waste. To achieve mercury contamination levels similar to those found in larger bulbs such as those used in DOE facilities a small amount of Hg was added to the crushed bulbs. The most effective agents for leaching mercury from the crushed fluorescent bulbs were KI/I2, NaOCl, and NaBr + acid. Radionuclide surrogates were added to both the EPA synthetic soil material and the crushed fluorescent bulbs to determine the fate of radionuclides following chemical leaching with the leaching agents determined to be the most promising. These experiments revealed that although over 98% of the dosed mercury solubilized and was found in the leaching solution, no Cerium was measured in the posttreatment leaching solution. This finding suggest that Uranium, for which Ce was used as a surrogate, would not solubilize during leaching of mercury contaminated soil or glass

  10. Chemical characterization, leach, and adsorption studies of solidified low-level wastes

    International Nuclear Information System (INIS)

    Laboratory and field leaching experiments are beig conducted by Pacific Northwest Laboratory (PNL) to investigate the performance of solidified low-level nuclear waste in a typical, arid, near-surface disposal site. Under PNL's Special Waste Form Lysimeters-Arid Program, a field test facility was constructed to monitor the leaching of commercial solidified waste. Laboratory experiments were conducted to investigate the leaching and adsorption characteristics of the waste forms in contact with soil. Liquid radioactive wastes solidified in cement, vinyl ester-styrene, and bitumen were obtained from commercial boiling water and pressurized water reactors, and buried in a field leaching facility on the Hanford site in southeastern Washington State. Batch leaching, soil column adsorption, and soil/waste form column experiments were conducted in the laboratory, using small-scale cement waste forms and Hanford site ground water. The purpose of these experiments is to evaluate the ability of laboratory leaching tests to predict leaching under actual field conditions and to determine which mechanisms (i.e., diffusion, solubility, adsorption) actually control the concentration of radionuclides in the soil surrounding the waste form. Chemical and radionuclide analyses performed on samples collected from the field and laboratory experiments indicate strong adsorption of /sup 134,137/Cs and 85Sr onto the Hanford site sediment. Small amounts of 60Co are leached from the waste forms as very mobile species. Some 60Co migrated through the soil at the same rate as water. Chemical constituents present in the reactor waste streams also found at elevated levels in the field and laboratory leachates include sodium, sulfate, magnesium, and nitrate. Plausible solid phases that could be controlling some of the chemical and radionuclide concentrations in the leachate were identified using the MINTEQ geochemical computer code

  11. Chemical characterization, leach, and adsorption studies of solidified low-level wastes

    Energy Technology Data Exchange (ETDEWEB)

    Walter, M.B.; Serne, R.J.; Jones, T.L.; McLaurine, S.B.

    1986-12-01

    Laboratory and field leaching experiments are beig conducted by Pacific Northwest Laboratory (PNL) to investigate the performance of solidified low-level nuclear waste in a typical, arid, near-surface disposal site. Under PNL's Special Waste Form Lysimeters-Arid Program, a field test facility was constructed to monitor the leaching of commercial solidified waste. Laboratory experiments were conducted to investigate the leaching and adsorption characteristics of the waste forms in contact with soil. Liquid radioactive wastes solidified in cement, vinyl ester-styrene, and bitumen were obtained from commercial boiling water and pressurized water reactors, and buried in a field leaching facility on the Hanford site in southeastern Washington State. Batch leaching, soil column adsorption, and soil/waste form column experiments were conducted in the laboratory, using small-scale cement waste forms and Hanford site ground water. The purpose of these experiments is to evaluate the ability of laboratory leaching tests to predict leaching under actual field conditions and to determine which mechanisms (i.e., diffusion, solubility, adsorption) actually control the concentration of radionuclides in the soil surrounding the waste form. Chemical and radionuclide analyses performed on samples collected from the field and laboratory experiments indicate strong adsorption of /sup 134,137/Cs and /sup 85/Sr onto the Hanford site sediment. Small amounts of /sup 60/Co are leached from the waste forms as very mobile species. Some /sup 60/Co migrated through the soil at the same rate as water. Chemical constituents present in the reactor waste streams also found at elevated levels in the field and laboratory leachates include sodium, sulfate, magnesium, and nitrate. Plausible solid phases that could be controlling some of the chemical and radionuclide concentrations in the leachate were identified using the MINTEQ geochemical computer code.

  12. Frequency of use controls chemical leaching from drinking-water containers subject to disinfection.

    Science.gov (United States)

    Andra, Syam S; Makris, Konstantinos C; Shine, James P

    2011-12-15

    Microbial-, and chemical-based burden of disease associated with lack of access to safe water continues to primarily impact developing countries. Cost-effective health risk-mitigating measures, such as of solar disinfection applied to microbial-contaminated water stored in plastic bottles have been increasingly tested in developing countries adversely impacted by epidemic water-borne diseases. Public health concerns associated with chemical leaching from water packaging materials led us to investigate the magnitude and variability of antimony (Sb) and bromine (Br) leaching from reused plastic containers (polyethylene terephthalate, PET; and polycarbonate, PC) subject to UV and/or temperature-driven disinfection. The overall objective of this study was to determine the main and interactive effects of temperature, UV exposure duration, and frequency of bottle reuse on the extent of leaching of Sb and Br from plastic bottles into water. Regardless of UV exposure duration, frequency of reuse (up to 27 times) was the major factor that linearly increased Sb leaching from PET bottles at all temperatures tested (13-47 °C). Leached Sb concentrations (∼360 ng L(-1)) from the highly reused (27 times) PET bottles (minimal Sb leaching from PC bottles, packaging materials is deemed necessary under relevant environmental conditions. PMID:22040714

  13. Speciation of heavy metals in garden soils. Evidences from selective and sequential chemical leaching

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Zhongqi; Lee, Leda; Dayan, Sara; Grinshtein, Michael [Brooklyn College of The City Univ. of New York, Brooklyn, NY (United States). Environmental Sciences Analytical Cnter; Shaw, Richard [USDA-NRCS NYC Soil Survey, Staten Island, NY (United States)

    2011-06-15

    Purpose: Gardening (especially food growing) in urban areas is becoming popular, but urban soils are often very contaminated for historical reasons. There is lack of sufficient information as to the bioavailability of soil heavy metals to plants and human in urban environments. This study examines the relative leachability of Cr, Ni, As, Cd, Zn, and Pb for soils with varying characteristics. The speciation and mobility of these metals can be qualitatively inferred from the leaching experiments. The goal is to use the data to shed some light on their bioavailability to plant and human, as well as the basis for soil remediation. Materials and methods: Selective and sequential chemical leaching methods were both used to evaluate the speciation of Cr, Ni, As, Cd, Zn, and Pb in soil samples collected from New York City residential and community gardens. The sequential leaching experiment followed a standard BCR four-step procedure, while selective leaching involved seven different chemical extractants. Results and discussion: The results from selective and sequential leaching methods are consistent. In general, very little of the heavy metals were found in the easily soluble or exchangeable fractions. Larger fractions of Cd and Zn can be leached out than other metals. Lead appears predominantly in the organic or carbonate fractions, of which {proportional_to} 30-60% is in the easily soluble organic fraction. Most As cannot be leached out by any of the extractants used, but it could have been complicated by the ineffective dissolution of oxides by ammonium hydroxylamine. Ni and Cr were mostly in the residual fractions but some released in the oxidizable fractions. Therefore, the leachability of metals follow the order Cd/Zn > Pb > Ni/Cr. Conclusions: Despite of the controversy and inaccuracy surrounding chemical leaching methods for the speciation of metals, chemical leaching data provide important, general, and easy-to-access information on the mobility of heavy metals

  14. Leaching Kinetics of Atrazine and Inorganic Chemicals in Tilled and Orchard Soils

    Science.gov (United States)

    Szajdak, Lech W.; Lipiec, Jerzy; Siczek, Anna; Nosalewicz, Artur; Majewska, Urszula

    2014-04-01

    The aim of this study was to verify first-order kinetic reaction rate model performance in predicting of leaching of atrazine and inorganic compounds (K+1, Fe+3, Mg+2, Mn+2, NH4 +, NO3 - and PO4 -3) from tilled and orchard silty loam soils. This model provided an excellent fit to the experimental concentration changes of the compounds vs. time data during leaching. Calculated values of the first-order reaction rate constants for the changes of all chemicals were from 3.8 to 19.0 times higher in orchard than in tilled soil. Higher first-order reaction constants for orchard than tilled soil correspond with both higher total porosity and contribution of biological pores in the former. The first order reaction constants for the leaching of chemical compounds enables prediction of the actual compound concentration and the interactions between compound and soil as affected by management system. The study demonstrates the effectiveness of simultaneous chemical and physical analyses as a tool for the understanding of leaching in variously managed soils.

  15. Heavy metal recovery from contaminated biomass ashes by chemical leaching, bioleaching and biosorption

    International Nuclear Information System (INIS)

    Ashes from biomass combustion plants contain plant nutrients which makes their application as fertilizers economically interesting. The possibility of recycling the ash can be looked upon as a contribution to obtain a sustainable energy utilization from biomass. The ash contains heavy metals which have to be removed. The possibility of decontaminating the ash by chemical and biological leaching was investigated. The leaching capacity of commercially available organic and inorganic acids and of citric acid produced by the fungus Penicillium simplicissimus were determined. A process for heavy metal recovery from biomass ashes consisting of four steps was designed. All environmentally relevant heavy metals (except lead) were removed from contaminated biomass ashes by chemical leaching. The heavy metals were recovered and enriched by precipitation and subsequent biosorption. Inactivated bacteria and fungi were used as biosorbents. The overall costs and the washing-out of plant nutrients from the ashes by chemical leaching were drawbacks of the metal recovering process. Biosorption in combination with existing processes of waste water treatment would offer another promising possibility for achieving the low Austrian limiting values for heavy metals in waste water. (author)

  16. Dielectric behaviour of MgFe2O4 prepared from chemically beneficiated iron ore rejects

    Indian Academy of Sciences (India)

    K S Rane; V M S Verenkar; P Y Sawant

    2001-06-01

    Chemically beneficiated high silica/alumina iron ore rejects (27–76% Fe2O3) were used to synthesize iron oxides of purity 96–98% with SiO2/Al2O3 ratio reduced to 0.03. The major impurities on chemical beneficiations were Al, Si, and Mn in the range 2–3%. A 99.73% purity Fe2O3 was also prepared by solvent extraction method using methyl isobutyl ketone (MIBK) from the acid extracts of the ore rejects. The magnesium ferrite, MgFe2O4, prepared from these synthetic iron oxides showed high resistivity of ∼ 108 ohm cm. All ferrites showed saturation magnetization, 4s, in the narrow range of 900–1200 Gauss and the Curie temperature, c, of all these fell within a small limit of 670 ± 30 K. All ferrites had low dielectric constants ('), 12–15, and low dielectric loss, tan , which decreased with the increase in frequency indicating a normal dielectric dispersion found in ferrites. The presence of insignificant amount of polarizable Fe2+ ions can be attributed to their high resistances and low dielectric constants. Impurities inherent in the samples had no marked influence on the electrical properties of the ferrites prepared from the iron ore rejects, suggesting the possibility of formation of ferrite of constant composition, MgFe2O4, of low magnetic and dielectric losses at lower temperatures of 1000°C by ceramic technique.

  17. Effect of Rain Leaching on Chemical Composition of Alfalfa Hay

    OpenAIRE

    Garcia de Hernandez, Mercedes M.

    1981-01-01

    Yield and chemical changes of second-cutting alfalfa hay treated with artificial rain were determined in a 2 x 3 x 2 factorial experiment. Factors were 2 stages of maturity (1 late vegetative; 2 early bloom), 3 levels of artificial rain applied (1 =no rain; 2 =low or approximately 5 mm; 3 =high or approximately 20 mm), and 2 times of applying artificial rain (1 = when drying forage was 40-60% dry matter; 2 =when drying forage was 60-75% dry matter). Thirty samples of alfalfa were collected at...

  18. Influence of physical and chemical factors on biological leaching process of copper from printed circuit boards

    OpenAIRE

    Willner, J

    2013-01-01

    The article presents the results of the research regarding the biological leaching of this metal from electronic wastes components in the form of printed circuit boards. The purpose of the study was to evaluate the influence of some physical and chemical factors (e.g. pH, oxidation-reduction potential) on bioleaching process and efficiency of copper transfer from solid phase into solution. Bioleaching experiments were carried out with pure cultures of Acidithiobacillus ferrooxidans. The obtai...

  19. Kinetics and Modeling of Chemical Leaching of Sphalerite Concentrate Using Ferric Iron in a Redox-controlled Reactor

    Institute of Scientific and Technical Information of China (English)

    宋健; 高玲; 林建群; 吴洪斌; 林建强

    2013-01-01

    This work presents a study for chemical leaching of sphalerite concentrate under various constant Fe3+concentrations and redox potential conditions. The effects of Fe3+ concentration and redox potential on chemical leaching of sphalerite were investigated. The shrinking core model was applied to analyze the experimental results. It was found that both the Fe3+ concentration and the redox potential controlled the chemical leaching rate of sphalerite. A new kinetic model was developed, in which the chemical leaching rate of sphalerite was proportional to Fe3+concentration and Fe3+/Fe2+ratio. All the model parameters were evaluated from the experimental data. The model predictions fit well with the experimental observed values.

  20. Bioleaching and chemical leaching of heavy metals from anaerobically digested sludge

    Energy Technology Data Exchange (ETDEWEB)

    Marchioretto, M.M.; Bruning, H.; Hien, N.T.P.; Rulkens, W.H.

    2003-07-01

    The present work aims to evaluate the practical application of bioleaching in the solubilization of Cr, Cu, Pb and Zn from anaerobically digested sludge. Chemical leaching with H{sub 2}SO{sub 4} and bioleaching with elemental sulfur and ferrous iron are applied. The results are compared with those found in the literature and in previous leaching experiments with HCl. Bioleaching can be a feasible alternative to promote Zn and Cu solubilizations, especially when ferrous iron is added as substrate. Under this condition, the maximum extraction yield achieved for Zn is 80.8 % with pH value of 2.7, and for Cu it is 65.5 % with pH value of 2.5. Cr solubilization is possible when pH is around 2.5 and Pb is not detected in solution. Chemical leaching with HCl at pH value of 1 solubilizes 100 % of Pb and also provides the best extraction yield for Cr (around 72 %). With the same pH value HCl is more effective than H{sub 2}SO{sub 4} to solubilize all the metals studied. (author)

  1. Influence of physical and chemical factors on biological leaching process of copper from printed circuit boards

    Directory of Open Access Journals (Sweden)

    J. Willner

    2013-04-01

    Full Text Available The article presents the results of the research regarding the biological leaching of this metal from electronic wastes components in the form of printed circuit boards. The purpose of the study was to evaluate the influence of some physical and chemical factors (e.g. pH, oxidation-reduction potential on bioleaching process and efficiency of copper transfer from solid phase into solution. Bioleaching experiments were carried out with pure cultures of Acidithiobacillus ferrooxidans. The obtained results were discussed.

  2. Comparative evaluation of microbial and chemical leaching processes for heavy metal removal from dewatered metal plating sludge

    Energy Technology Data Exchange (ETDEWEB)

    Bayat, Belgin, E-mail: bbayat@cu.edu.tr [Department of Environmental Engineering, Faculty of Engineering and Architecture, Cukurova University, Balcali, Adana 01330 (Turkey); Sari, Bulent [Department of Environmental Engineering, Faculty of Engineering and Architecture, Cukurova University, Balcali, Adana 01330 (Turkey)

    2010-02-15

    The purpose of the study described in this paper was to evaluate the application of bioleaching technique involving Acidithiobacillus ferrooxidans to recover heavy metals (Zn, Cu, Ni, Pb, Cd and Cr) in dewatered metal plating sludge (with no sulfide or sulfate compounds). The effect of some conditional parameters (i.e. pH, oxidation-reduction potential (ORP), sulfate production) and operational parameters (i.e. pulp density of the sludge and agitation time) were investigated in a 3 l completely mixed batch (CMB) reactor. The metal recovery yields in bioleaching were also compared with chemical leaching of the sludge waste using commercial inorganic acids (sulfuric acids and ferric chloride). The leaching of heavy metals increased with decreasing of pH and increasing of ORP and sulfate production during the bioleaching experiment. Optimum pulp density for bioleaching was observed at 2% (w/v), and leaching efficiency decreased with increasing pulp density in bioleaching experiments. Maximum metal solubilization (97% of Zn, 96% of Cu, 93% of Ni, 84% of Pb, 67% of Cd and 34% of Cr) was achieved at pH 2, solids contents of 2% (w/v), and a reaction temperature of 25 {+-} 2 deg. C during the bioleaching process. The maximum removal efficiencies of 72% and 79% Zn, 70% and 75% Cu, 69% and 73% Ni, 57% and 70% Pb, 55% and 65% Cd, and 11% and 22% Cr were also attained with the chemical leaching using sulfuric acids and ferric chloride, respectively, at pH 2, solids contents of 2% (w/v), and a reaction temperature of 25 {+-} 2 deg. C during the acid leaching processes. The rates of metal leaching for bioleaching and chemical leaching are well described by a kinetic equation related to time. Although bioleaching generally requires a longer period of operation compared to chemical leaching, it achieves higher removal efficiency for heavy metals. The efficiency of leaching processes can be arranged in descending order as follows: bioleaching > ferric chloride leaching > sulfuric

  3. Comparative evaluation of microbial and chemical leaching processes for heavy metal removal from dewatered metal plating sludge

    International Nuclear Information System (INIS)

    The purpose of the study described in this paper was to evaluate the application of bioleaching technique involving Acidithiobacillus ferrooxidans to recover heavy metals (Zn, Cu, Ni, Pb, Cd and Cr) in dewatered metal plating sludge (with no sulfide or sulfate compounds). The effect of some conditional parameters (i.e. pH, oxidation-reduction potential (ORP), sulfate production) and operational parameters (i.e. pulp density of the sludge and agitation time) were investigated in a 3 l completely mixed batch (CMB) reactor. The metal recovery yields in bioleaching were also compared with chemical leaching of the sludge waste using commercial inorganic acids (sulfuric acids and ferric chloride). The leaching of heavy metals increased with decreasing of pH and increasing of ORP and sulfate production during the bioleaching experiment. Optimum pulp density for bioleaching was observed at 2% (w/v), and leaching efficiency decreased with increasing pulp density in bioleaching experiments. Maximum metal solubilization (97% of Zn, 96% of Cu, 93% of Ni, 84% of Pb, 67% of Cd and 34% of Cr) was achieved at pH 2, solids contents of 2% (w/v), and a reaction temperature of 25 ± 2 deg. C during the bioleaching process. The maximum removal efficiencies of 72% and 79% Zn, 70% and 75% Cu, 69% and 73% Ni, 57% and 70% Pb, 55% and 65% Cd, and 11% and 22% Cr were also attained with the chemical leaching using sulfuric acids and ferric chloride, respectively, at pH 2, solids contents of 2% (w/v), and a reaction temperature of 25 ± 2 deg. C during the acid leaching processes. The rates of metal leaching for bioleaching and chemical leaching are well described by a kinetic equation related to time. Although bioleaching generally requires a longer period of operation compared to chemical leaching, it achieves higher removal efficiency for heavy metals. The efficiency of leaching processes can be arranged in descending order as follows: bioleaching > ferric chloride leaching > sulfuric acid

  4. Chemical Criteria to Assess Risk of Phosphorus Leaching from Urban Soils

    Institute of Scientific and Technical Information of China (English)

    ZHANG Gan-Lin; W. BURGHARDT; YANG Jin-Ling

    2005-01-01

    Soils from urban and suburban areas are normally enriched with phosphorus (P). Sixteen urban soils with a wide range of total P concentrations under typical urban land uses were sampled and analyzed for extractable P concentrations using water, sodium bicarbonate and citric acid. Meanwhile the soils were artificially leached in columns and P concentrations in the leachates were determined. With linear regression a two-stage linear relationship was found to exist between concentrations of P in the leachates and soil P contents obtained by various chemical measurements, i.e., there was a "change-point" denoting the critical threshold value for extractable P between the regression lines, above which concentrations of P in leachates increased substantially. These threshold "change-point" values were 1.5 mg kg-1 for water-soluble P and CaC12-P, 25 mg kg-1 for Olsen-P, and 250-350 mg kg-1 for citric acid-P with the sharpest change and the best predictor [r2 (upper) = 0.928, r2 (lower)= 0.807] appearing for Olsen-P. These "change-points" were considered important criteria in assessing the risk of P leaching from urban soils and could be used as standards to delineate and target hazardous areas in urban and suburban areas.

  5. Estrogenic chemicals often leach from BPA-free plastic products that are replacements for BPA-containing polycarbonate products

    Science.gov (United States)

    2014-01-01

    Background Xenobiotic chemicals with estrogenic activity (EA), such as bisphenol A (BPA), have been reported to have potential adverse health effects in mammals, including humans, especially in fetal and infant stages. Concerns about safety have caused many manufacturers to use alternatives to polycarbonate (PC) resins to make hard and clear, reusable, plastic products that do not leach BPA. However, no study has focused on whether such BPA-free PC-replacement products, chosen for their perceived higher safety, especially for babies, also release other chemicals that have EA. Methods We used two, well-established, mammalian cell-based, assays (MCF-7 and BG1Luc) to assess the EA of chemicals that leached into over 1000 saline or ethanol extracts of 50 unstressed or stressed (autoclaving, microwaving, and UV radiation) BPA-free PC-replacement products. An EA antagonist, ICI 182,780, was used to confirm that agonist activity in leachates was due to chemicals that activated the mammalian estrogen receptor. Results Many unstressed and stressed, PC-replacement-products made from acrylic, polystyrene, polyethersulfone, and Tritan™ resins leached chemicals with EA, including products made for use by babies. Exposure to various forms of UV radiation often increased the leaching of chemicals with EA. In contrast, some BPA-free PC-replacement products made from glycol-modified polyethylene terephthalate or cyclic olefin polymer or co-polymer resins did not release chemicals with detectable EA under any conditions tested. Conclusions This hazard assessment survey showed that many BPA-free PC- replacement products still leached chemicals having significant levels of EA, as did BPA-containing PC counterparts they were meant to replace. That is, BPA-free did not mean EA-free. However, this study also showed that some PC-replacement products did not leach chemicals having significant levels of EA. That is, EA-free PC-replacement products could be made in commercial quantities at

  6. Estrogenic chemicals often leach from BPA-free plastic products that are replacements for BPA-containing polycarbonate products

    OpenAIRE

    Bittner, George D; Yang, Chun Z.; Stoner, Matthew A

    2014-01-01

    Background Xenobiotic chemicals with estrogenic activity (EA), such as bisphenol A (BPA), have been reported to have potential adverse health effects in mammals, including humans, especially in fetal and infant stages. Concerns about safety have caused many manufacturers to use alternatives to polycarbonate (PC) resins to make hard and clear, reusable, plastic products that do not leach BPA. However, no study has focused on whether such BPA-free PC-replacement products, chosen for their perce...

  7. Transfer of chemical elements from a contaminated estuarine sediment to river water. A leaching assay

    Science.gov (United States)

    Abreu, Manuela; Peres, Sara; Magalhães, M. Clara F.

    2014-05-01

    Wastes of a former Portuguese steel industry were deposited during 40 years on the left bank of the Coina River, which flows into the estuary of the Tagus River near Lisbon. The aim of this study was to evaluate the release of the chemical elements from the contaminated sediment to the river water. A leaching experiment (four replicates) was performed using 1.6 kg/replicate of sediment from a landfill located in the Coina River bank, forming a lagoon subject to tidal influence. River water coming from this lagoon was collected during low tide. This water (200 mL) was added to the moist sediment, contained in cylindrical reactors, and was collected after 24 h of percolation. The leaching experiments were conducted for 77 days being leachates collected at time zero, after 28, 49 and 77 days with the sediment always moist. The sediment was characterized for: pH, electric conductivity (EC), total organic carbon (TOC), extractable phosphorus and potassium, mineral nitrogen, iron from iron oxides (crystalline and non-crystalline) and manganese oxides. Multi-elemental analysis was also made by ICP-INAA. Leachates and river water were analysed for pH, EC, hydrogencarbonate and sulfatetot by titrations, chloride by potentiometry, and multi-elemental composition by ICP-MS. The sediment presented pH=7.2, EC=18.5 dS/m, TOC=147.8 g/kg, high concentrations of extractable phosphorous (62.8 mg/kg) and potassium (1236.8 mg/kg), mineral nitrogen=11.3 mg/kg. The non-crystalline fraction of iron oxides corresponds to 99% (167.5 g Fe/kg) of the total iron oxides, and manganese from manganese oxides was low (52.7 mg/kg). Sediment is considered contaminated. It contained high concentrations (g/kg) of Zn (2.9), Pb (0.9), Cr (0.59), Cu (0.16), As (0.07), Cd (0.005), and Hg (0.001), which are above Canadian values for marine sediments quality guidelines for protection of aquatic life. River water had: pH=8.2, EC=28.6 dS/m, csulfate=1.23 g/L, and [Cl-]=251.6 mg/L. The concentrations of Cd (0

  8. Coupling between chemical degradation and mechanical behaviour of leached concrete; Couplage degradation chimique - comportement en compression du beton

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, V.H

    2005-10-15

    This work is in the context of the long term behavior of concrete employed in radioactive waste disposal. The objective is to study the coupled chemo-mechanical modelling of concrete. In the first part of this contribution, experimental investigations are described where the effects of the calcium leaching process of concrete on its mechanical properties are highlighted. An accelerated method has been chosen to perform this leaching process by using an ammonium nitrate solution. In the second part, we present a coupled phenomenological chemo-mechanical model that represents the degradation of concrete materials. On one hand, the chemical behavior is described by the simplified calcium leaching approach of cement paste and mortar. Then a homogenization approach using the asymptotic development is presented to take into account the influence of the presence of aggregates in concrete. And on the other hand, the mechanical part of the modelling is given. Here continuum damage mechanics is used to describe the mechanical degradation of concrete. The growth of inelastic strains observed during the mechanical tests is describes by means of a plastic like model. The model is established on the basis of the thermodynamics of irreversible processes framework. The coupled nonlinear problem at hand is addressed within the context of the finite element method. Finally, numerical simulations are compared with the experimental results for validation. (author)

  9. Disturbance Rejection

    OpenAIRE

    2005-01-01

    This interactive tutorial reviews the disturbance rejection capabilities of different feedback control schemes. The interactions in this tutorial involve students analyzing 4 cases of step-like disturbance rejection. ME2801 Introduction to Engineering System Dynamics

  10. Characterization of Leached Phosphorus from Soil, Manure, and Manure-Amended Soil by Physical and Chemical Fractionation and Diffusive Gradients in Thin Films (DGT)

    DEFF Research Database (Denmark)

    Glæsner, Nadia; Donner, Erica; Magid, Jakob;

    2012-01-01

    We are challenged to date to fully understand mechanisms controlling phosphorus (P) mobilization in soil. In this study we evaluated physical properties, chemical reactivity, and potential bioavailability of P mobilized in soil during a leaching event and examined how the amounts and properties...... of leached P were influenced by surface application of cattle manure. Leaching experiments on manure itself, and on intact soil columns (14.1 cm inner dia., 25 cm height) before and after manure application, were carried out at an irrigation rate of 1 mm h−1 for 48 h. High concentrations of dissolved...... with manure. Manure particles themselves were also largely retained by the soil. Combined physical (centrifugation) and chemical (molybdate reactiveness) fractionation of leached P showed that leachates in the manure treated soils were dominated by dissolved unreactive P (DUP), mainly originating from manure...

  11. Chemical extraction of copper from copper sulphide ores of Pakistan by roast leach method

    International Nuclear Information System (INIS)

    Copper ores, containing both complex sulphide minerals and those containing chalcopyrite mineral, were studied for the extraction of copper by leaching after roasting. Roasting at 650 deg. C for 30 min rendered the ore leachable in dilute sulphuric acid of 2.5% concentration. The process of metal extraction would be of hydro metallurgical importance for low to high grade sulphide and polymetallic complex sulphide ores occurring in Pakistan. The kinetic models of roasting reaction fit phase boundary as well as diffusion reaction mechanism. (author)

  12. Rejecting Change

    Institute of Scientific and Technical Information of China (English)

    KERRY; BROWN

    2011-01-01

    British voters overwhelmingly reject an alternative voting system The British electorate,in only the second ever national referendum held in their history (the first was on joining the EU,over 35 years ago) rejected alterations to their voting system from the current first-past-the-post system to a form of alternative voting similar to that used

  13. Comparative Mapping of Soil Physical-Chemical and Structural Parameters at Field Scale to Identify Zones of Enhanced Leaching Risk

    DEFF Research Database (Denmark)

    Nørgaard, Trine; Møldrup, Per; Olsen, Preben;

    2013-01-01

    and organic carbon content and investigate whether it was possible to relate these to derived structural parameters such as bulk density and conservative tracer parameters and to actual particle and phosphorus leaching patterns obtained from laboratory leaching experiments. Sixty-five cylindrical soil columns...... characteristics including soil texture, bulk density, dissolved tracer, particle and phosphorus transport parameters identified the northern one-third of the field as a zone with higher leaching risk. This risk assessment based on parameter mapping from measurements on intact samples was in good agreement...

  14. Experimental design and optimization of leaching process for recovery of valuable chemical elements (U, La, V, Mo, Yb and Th) from low-grade uranium ore

    Energy Technology Data Exchange (ETDEWEB)

    Zakrzewska-Koltuniewicz, Grażyna, E-mail: g.zakrzewska@ichtj.waw.pl [Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw (Poland); Herdzik-Koniecko, Irena [Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw (Poland); Cojocaru, Corneliu [Institute of Macromolecular Chemistry “Petru Poni”, Aleea Grigore Ghica Voda, nr. 41A, 700487 Iasi (Romania); Chajduk, Ewelina [Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw (Poland)

    2014-06-30

    Highlights: • The experimental design for optimization of leaching process of uranium from low-grade ores was applied. • Multi-objective optimization method based on desirability approach was employed. • The recovery of associated metals like vanadium, molybdenum and lanthanides was considered. • The effects of factors were identified by 3-D surface plots. • The optimum condition for valuable metals: P = 5 bar, T = 120 °C and t = 90 min has been determined. - Abstract: The paper deals with experimental design and optimization of leaching process of uranium and associated metals from low-grade, Polish ores. The chemical elements of interest for extraction from the ore were U, La, V, Mo, Yb and Th. Sulphuric acid has been used as leaching reagent. Based on the design of experiments the second-order regression models have been constructed to approximate the leaching efficiency of elements. The graphical illustrations using 3-D surface plots have been employed in order to identify the main, quadratic and interaction effects of the factors. The multi-objective optimization method based on desirability approach has been applied in this study. The optimum condition have been determined as P = 5 bar, T = 120 °C and t = 90 min. Under these optimal conditions, the overall extraction performance is 81.43% (for U), 64.24% (for La), 98.38% (for V), 43.69% (for Yb) and 76.89% (for Mo) and 97.00% (for Th)

  15. Comparative mapping of soil physical-chemical and structural parameters at field scale to identify zones of enhanced leaching risk.

    Science.gov (United States)

    Norgaard, Trine; Moldrup, Per; Olsen, Preben; Vendelboe, Anders L; Iversen, Bo V; Greve, Mogens H; Kjaer, Jeanne; de Jonge, Lis W

    2013-01-01

    Preferential flow and particle-facilitated transport through macropores contributes significantly to the transport of strongly sorbing substances such as pesticides and phosphorus. The aim of this study was to perform a field-scale characterization of basic soil physical properties like clay and organic carbon content and investigate whether it was possible to relate these to derived structural parameters such as bulk density and conservative tracer parameters and to actual particle and phosphorus leaching patterns obtained from laboratory leaching experiments. Sixty-five cylindrical soil columns of 20-cm height and 20-cm diameter and bulk soil were sampled from the topsoil in a 15-m × 15-m grid in an agricultural loamy field. Highest clay contents and highest bulk densities were found in the northern part of the field. Leaching experiments with a conservative tracer showed fast 5% tracer arrival times and high tracer recovery percentages from columns sampled from the northern part of the field, and the leached mass of particles and particulate phosphorus was also largest from this area. Strong correlations were obtained between 5% tracer arrival time, tracer recovery, and bulk density, indicating that a few well-aligned and better connected macropores might change the hydraulic conductivity between the macropores and the soil matrix, triggering an onset of preferential flow at lower rain intensities compared with less compacted soil. Overall, a comparison mapping of basic and structural characteristics including soil texture, bulk density, dissolved tracer, particle and phosphorus transport parameters identified the northern one-third of the field as a zone with higher leaching risk. This risk assessment based on parameter mapping from measurements on intact samples was in good agreement with 9 yr of pesticide detections in two horizontal wells and with particle and phosphorus leaching patterns from a distributed, shallow drainage pipe system across the field

  16. Chemical durability and leaching mechanism of Ce0.5Eu0.5PO4 ceramics: Effects of temperature and pH values

    Science.gov (United States)

    Zhao, Xiaofeng; Teng, Yuancheng; Wu, Lang; Huang, Yi; Ma, Jiyan; Wang, Guolong

    2015-11-01

    Ce0.5Eu0.5PO4 ceramics with high relative density were prepared by hot-press (HPS) and pressureless (PLS) sintering. The effects of temperature and pH values on the chemical durability of the ceramics were investigated. The results show that an increase of acidity significantly accelerated the corrosion of the samples. In alkaline leachates, further release elements were prevented by the newborn surface precipitation. The leach rate (Rn) of HPS sample was similar to that of PLS specimen in deionized water, but higher Rn for PLS sample was found in pH = 11 solution. Moreover, apparent activation energy of the dissolution of Eu (40 ± 4 kJ mol-1) is much higher than that of Ce (20 ± 1 kJ mol-1), leading to the higher normalized elemental leach rate of Eu. Both the Eu and Ce elements have low leach rates (10-12-10-9 m d-1) after 42 days in all the leachates studied in this work.

  17. Leaching From Biomass Gasification Residues

    DEFF Research Database (Denmark)

    Allegrini, Elisa; Boldrin, Alessio; Polletini, A.;

    2011-01-01

    with geochemical modelling were carried out both on fresh and aged samples. The results showed that the material is comparable to residues from wood combustion and the leaching behaviour was dominated by Ca-containing minerals and solid solutions. Heavy metals were detected in very low concentrations in the bulk......The aim of the present work is to attain an overall characterization of solid residues from biomass gasification. Besides the determination of chemical and physical properties, the work was focused on the study of leaching behaviour. Compliance and pH-dependence leaching tests coupled...

  18. A preferential flow leaching index

    NARCIS (Netherlands)

    McGrath, G.S.; Hinz, C.; Sivapalan, M.

    2009-01-01

    The experimental evidence suggests that for many chemicals surface runoff and rapid preferential flow through the shallow unsaturated zone are significant pathways for transport to streams and groundwater. The signature of this is the episodic and pulsed leaching of these chemicals. The driver for t

  19. Valorization of GaN based metal-organic chemical vapor deposition dust a semiconductor power device industry waste through mechanochemical oxidation and leaching: A sustainable green process.

    Science.gov (United States)

    Swain, Basudev; Mishra, Chinmayee; Lee, Chan Gi; Park, Kyung-Soo; Lee, Kun-Jae

    2015-07-01

    Dust generated during metal organic vapor deposition (MOCVD) process of GaN based semiconductor power device industry contains significant amounts of gallium and indium. These semiconductor power device industry wastes contain gallium as GaN and Ga0.97N0.9O0.09 is a concern for the environment which can add value through recycling. In the present study, this waste is recycled through mechanochemical oxidation and leaching. For quantitative recovery of gallium, two different mechanochemical oxidation leaching process flow sheets are proposed. In one process, first the Ga0.97N0.9O0.09 of the MOCVD dust is leached at the optimum condition. Subsequently, the leach residue is mechanochemically treated, followed by oxidative annealing and finally re-leached. In the second process, the MOCVD waste dust is mechanochemically treated, followed by oxidative annealing and finally leached. Both of these treatment processes are competitive with each other, appropriate for gallium leaching and treatment of the waste MOCVD dust. Without mechanochemical oxidation, 40.11 and 1.86 w/w% of gallium and Indium are leached using 4M HCl, 100°C and pulp density of 100 kg/m(3,) respectively. After mechanochemical oxidation, both these processes achieved 90 w/w% of gallium and 1.86 w/w% of indium leaching at their optimum condition.

  20. Valorization of GaN based metal-organic chemical vapor deposition dust a semiconductor power device industry waste through mechanochemical oxidation and leaching: A sustainable green process

    International Nuclear Information System (INIS)

    Dust generated during metal organic vapor deposition (MOCVD) process of GaN based semiconductor power device industry contains significant amounts of gallium and indium. These semiconductor power device industry wastes contain gallium as GaN and Ga0.97N0.9O0.09 is a concern for the environment which can add value through recycling. In the present study, this waste is recycled through mechanochemical oxidation and leaching. For quantitative recovery of gallium, two different mechanochemical oxidation leaching process flow sheets are proposed. In one process, first the Ga0.97N0.9O0.09 of the MOCVD dust is leached at the optimum condition. Subsequently, the leach residue is mechanochemically treated, followed by oxidative annealing and finally re-leached. In the second process, the MOCVD waste dust is mechanochemically treated, followed by oxidative annealing and finally leached. Both of these treatment processes are competitive with each other, appropriate for gallium leaching and treatment of the waste MOCVD dust. Without mechanochemical oxidation, 40.11 and 1.86 w/w% of gallium and Indium are leached using 4 M HCl, 100 °C and pulp density of 100 kg/m3, respectively. After mechanochemical oxidation, both these processes achieved 90 w/w% of gallium and 1.86 w/w% of indium leaching at their optimum condition. - Highlights: • Waste MOCVD dust is treated through mechanochemical leaching. • GaN is hardly leached, and converted to NaGaO2 through ball milling and annealing. • Process for gallium recovery from waste MOCVD dust has been developed. • Thermal analysis and phase properties of GaN to Ga2O3 and GaN to NaGaO2 is revealed. • Solid-state chemistry involved in this process is reported

  1. Preparation of porous bio-char and activated carbon from rice husk by leaching ash and chemical activation.

    Science.gov (United States)

    Ahiduzzaman, Md; Sadrul Islam, A K M

    2016-01-01

    Preparation porous bio-char and activated carbon from rice husk char study has been conducted in this study. Rice husk char contains high amount silica that retards the porousness of bio-char. Porousness of rice husk char could be enhanced by removing the silica from char and applying heat at high temperature. Furthermore, the char is activated by using chemical activation under high temperature. In this study no inert media is used. The study is conducted at low oxygen environment by applying biomass for consuming oxygen inside reactor and double crucible method (one crucible inside another) is applied to prevent intrusion of oxygen into the char. The study results shows that porous carbon is prepared successfully without using any inert media. The adsorption capacity of material increased due to removal of silica and due to the activation with zinc chloride compared to using raw rice husk char. The surface area of porous carbon and activated carbon are found to be 28, 331 and 645 m(2) g(-1) for raw rice husk char, silica removed rice husk char and zinc chloride activated rice husk char, respectively. It is concluded from this study that porous bio-char and activated carbon could be prepared in normal environmental conditions instead of inert media. This study shows a method and possibility of activated carbon from agro-waste, and it could be scaled up for commercial production. PMID:27536531

  2. Preparation of porous bio-char and activated carbon from rice husk by leaching ash and chemical activation.

    Science.gov (United States)

    Ahiduzzaman, Md; Sadrul Islam, A K M

    2016-01-01

    Preparation porous bio-char and activated carbon from rice husk char study has been conducted in this study. Rice husk char contains high amount silica that retards the porousness of bio-char. Porousness of rice husk char could be enhanced by removing the silica from char and applying heat at high temperature. Furthermore, the char is activated by using chemical activation under high temperature. In this study no inert media is used. The study is conducted at low oxygen environment by applying biomass for consuming oxygen inside reactor and double crucible method (one crucible inside another) is applied to prevent intrusion of oxygen into the char. The study results shows that porous carbon is prepared successfully without using any inert media. The adsorption capacity of material increased due to removal of silica and due to the activation with zinc chloride compared to using raw rice husk char. The surface area of porous carbon and activated carbon are found to be 28, 331 and 645 m(2) g(-1) for raw rice husk char, silica removed rice husk char and zinc chloride activated rice husk char, respectively. It is concluded from this study that porous bio-char and activated carbon could be prepared in normal environmental conditions instead of inert media. This study shows a method and possibility of activated carbon from agro-waste, and it could be scaled up for commercial production.

  3. Task 38 - commercial mercury remediation demonstrations: Thermal retorting and physical separation/chemical leaching. Topical report, December 1, 1994--June 30, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Charlton, D.S.; Fraley, R.H.; Stepan, D.J.

    1998-12-31

    Results are presented on the demonstration of two commercial technologies for the removal of mercury from soils found at natural gas metering sites. Technologies include a thermal retorting process and a combination of separation, leaching, and electrokinetic separation process.

  4. Rule of oxygen transmission in dump leaching

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    According to the chemical equations, the flux and concentration of oxygen required during bacterial leaching sulfuric mineral were investigated; the rule of air bubble transmitted in granular was researched in the Dump Leaching Plant of Dexing Copper Mine. The results show that lack of oxygen in dump leaching is the critical factor of restricting leaching reaction. Pyrite is the primary oxygen-consuming mineral in bioleaching. When its content is too high, it needs a great deal of oxygen for reaction and competes for the finite oxygen with objective minerals, and thus the leaching velocity decreases greatly. The average size of ore particles and diameter of bubbles are the key parameters affecting the mass transfer coefficient. Reverse analysis was adopted, and it shows that 44.8 m3 air per unit ore can meet the requirement of production if the molar ratio of pyrite to chalcopyrite is 10.

  5. Experimental methodology for assessing the environmental fate of organic chemicals in polymer matrices using column leaching studies and OECD 308 water/sediment systems: Application to tire and road wear particles

    Energy Technology Data Exchange (ETDEWEB)

    Unice, Kenneth M., E-mail: ken.unice@cardno.com; Bare, Jennifer L.; Kreider, Marisa L.; Panko, Julie M.

    2015-11-15

    Automobile tires require functional rubber additives including curing agents and antioxidants, which are potentially environmentally available from tire and road wear particles (TRWP) deposited in soil and sediment. A novel methodology was employed to evaluate the environmental fate of three commonly-used tire chemicals (N-cyclohexylbenzothiazole-2-sulfenamide (CBS), N-(1,3-dimethylbutyl)-N′-phenyl-1,4-phenylenediamine (6-PPD) and 1,3-diphenylguanidine (DPG)), using a road simulator, an artificial weathering chamber, column leaching tests, and OECD 308 sediment/water incubator studies. Environmental release factors were quantified for curing (f{sub C}), tire wear (f{sub W}), terrestrial weathering (f{sub S}), leaching from TRWP (f{sub L}), and environmental availability from TRWP (f{sub A}) by liquid chromatography–tandem mass spectroscopy (LC/MS/MS) analyses. Cumulative fractions representing total environmental availability (F{sub T}) and release to water (F{sub R}) were calculated for the tire chemicals and 13 transformation products. F{sub T} for CBS, DPG and 6-PPD inclusive of transformation products for an accelerated terrestrial aging time in soil of 0.1 years was 0.08, 0.1, and 0.06, respectively (equivalent to 6 to 10% of formulated mass). In contrast, a wider range of 5.5 × 10{sup −4} (6-PPD) to 0.06 (CBS) was observed for F{sub R} at an accelerated age of 0.1 years, reflecting the importance of hydrophobicity and solubility for determining the release to the water phase. Significant differences (p < 0.05) in the weathering factor, f{sub S}, were observed when chemicals were categorized by boiling point or hydrolysis rate constant. A significant difference in the leaching factor, f{sub L}, and environmental availability factor, f{sub A,} was also observed when chemicals were categorized by log K{sub ow}. Our methodology should be useful for lifecycle analysis of other functional polymer chemicals. - Highlights: • Studied two vulcanization

  6. Chronic alloantibody mediated rejection

    OpenAIRE

    Smith, R. Neal; Colvin, Robert B.

    2011-01-01

    Alloantibodies clearly cause acute antibody mediated rejection, and all available evidence supports their pathogenic etiology in the development of chronic alloantibody mediated rejection (CAMR). But the slow evolution of this disease, the on-going immunosuppression, the variations in titer of alloantibodies, and variation in antigenic targets all complicate identifying which dynamic factors are most important clinically and pathologically. This review highlights the pathological factors rela...

  7. Experimental methodology for assessing the environmental fate of organic chemicals in polymer matrices using column leaching studies and OECD 308 water/sediment systems: Application to tire and road wear particles.

    Science.gov (United States)

    Unice, Kenneth M; Bare, Jennifer L; Kreider, Marisa L; Panko, Julie M

    2015-11-15

    Automobile tires require functional rubber additives including curing agents and antioxidants, which are potentially environmentally available from tire and road wear particles (TRWP) deposited in soil and sediment. A novel methodology was employed to evaluate the environmental fate of three commonly-used tire chemicals (N-cyclohexylbenzothiazole-2-sulfenamide (CBS), N-(1,3-dimethylbutyl)-N'-phenyl-1,4-phenylenediamine (6-PPD) and 1,3-diphenylguanidine (DPG)), using a road simulator, an artificial weathering chamber, column leaching tests, and OECD 308 sediment/water incubator studies. Environmental release factors were quantified for curing (f(C)), tire wear (f(W)), terrestrial weathering (f(S)), leaching from TRWP (f(L)), and environmental availability from TRWP (f(A)) by liquid chromatography-tandem mass spectroscopy (LC/MS/MS) analyses. Cumulative fractions representing total environmental availability (F(T)) and release to water (FR) were calculated for the tire chemicals and 13 transformation products. F(T) for CBS, DPG and 6-PPD inclusive of transformation products for an accelerated terrestrial aging time in soil of 0.1 years was 0.08, 0.1, and 0.06, respectively (equivalent to 6 to 10% of formulated mass). In contrast, a wider range of 5.5×10(-4) (6-PPD) to 0.06 (CBS) was observed for F(R) at an accelerated age of 0.1 years, reflecting the importance of hydrophobicity and solubility for determining the release to the water phase. Significant differences (pboiling point or hydrolysis rate constant. A significant difference in the leaching factor, f(L), and environmental availability factor, f(A), was also observed when chemicals were categorized by log K(ow). Our methodology should be useful for lifecycle analysis of other functional polymer chemicals. PMID:26184905

  8. Discerning Rejection of Technology

    Directory of Open Access Journals (Sweden)

    Sudhir Rama Murthy

    2013-04-01

    Full Text Available Technology is innate to modern society and primarily embodies human intellect. It greatly influences development, societal functioning, and sociotechnical transitions. Rapid technological advancements, made possible with advancement in science, human ingenuity, and competitive markets, provide human society with affordable and unlimited choice. A society can be viewed, with an individual as the fundamental unit, or as a community, or state/nation. In one view, sustainability can be viewed through a matrix of societal, economic, and environmental configurations associated with the three societal levels. Technological advancement and complexity can either remain simple and amenable to the user or, as emerging in recent years, may daunt the user to keep away. While the phenomenon of technology adoption (acceptance in society has been well appreciated, the increasingly characteristic phenomenon of technology rejection is yet to be understood and studied. Technology rejection is not merely a negation of its acceptance, and hence requires to be discerned carefully. Rejection also does not imply in its totality, but varies in terms of its kind and/or intensiveness. While rejection is discernable at all these three levels of society, this study remains focused at the level of the user (individual. It attempts to discern rejection of technology and discusses its distinctness from technology acceptance through an exhaustive literature study. The article initially discusses the technology–society nexus and provides a preliminary technology–user interface model leading to a detailed discussion into the determinants of technology rejection.

  9. Column leaching from biomass combustion ashes

    DEFF Research Database (Denmark)

    Maresca, Alberto; Astrup, Thomas Fruergaard

    2015-01-01

    this study, a fly ash sample from an operating Danish power plant based on wood biomass was collected, chemically characterized and investigated for its leaching release of nutrients and heavy metals. A column leaching test was employed. The strongly alkaline pH of all the collected eluates suggested...... the potential suitability of the ash as a liming material. Although high contents of nutrients were detected, differences in their leaching release were found. Heavy metals were detected within typical literature contents for Nordic countries ashes....

  10. Geochemical association of Pu and Am in selected host-phases of contaminated soils from the UK and their susceptibility to chemical and microbiological leaching.

    Science.gov (United States)

    Kimber, Richard L; Corkhill, Claire L; Amos, Sean; Livens, Francis R; Lloyd, Jonathan R

    2015-04-01

    Understanding the biogeochemical behaviour and potential mobility of actinides in soils and groundwater is vital for developing remediation and management strategies for radionuclide-contaminated land. Pu is known to have a high Kd in soils and sediments, however remobilization of low concentrations of Pu remains a concern. Here, some of the physicochemical properties of Pu and the co-contaminant, Am, are investigated in contaminated soils from Aldermaston, Berkshire, UK, and the Esk Estuary, Cumbria, UK, to determine their potential mobility. Sequential extraction techniques were used to examine the host-phases of the actinides in these soils and their susceptibility to microbiological leaching was investigated using acidophilic sulphur-oxidising bacteria. Sequential extractions found the majority of (239,240)Pu associated with the highly refractory residual phase in both the Aldermaston (63.8-85.5 %) and Esk Estuary (91.9-94.5%) soils. The (241)Am was distributed across multiple phases including the reducible oxide (26.1-40.0%), organic (45.6-63.6%) and residual fractions (1.9-11.1%). Plutonium proved largely resistant to leaching from microbially-produced sulphuric acid, with a maximum 0.18% leached into solution, although up to 12.5% of the (241)Am was leached under the same conditions. If Pu was present as distinct oxide particles in the soil, then (241)Am, a decay product of Pu, would be expected to be physically retained in the particle. The differences in geochemical association and bioleachability of the two actinides suggest that this is not the case and hence, that significant Pu is not present as distinct particles. These data suggest the majority of Pu in the contaminated soils studied is highly recalcitrant to geochemical changes and is likely to remain immobile over significant time periods, even when challenged with aggressive "bioleaching" bacteria.

  11. SOC REJECTION BY NANOFILTRATION

    Science.gov (United States)

    A study was conducted to evaluate the rejection of six synthetic organic compounds (SOCs) from a potable water source by a nanofiltration membrane process. The S0Cs were ethylene dibromide (EDB), dibromochloropropane (DBCP), chlordane, heptachlor, methoxychlor and alachlor. To in...

  12. Immobilized waste leaching

    International Nuclear Information System (INIS)

    The main mechanism by which the immobilized radioactive materials can return to biosphere is the leaching due to the intrusion of water into the repositories. Some mathematical models and experiments utilized to evaluate the leaching rates in different immobilization matrices are described. (author)

  13. In situ leaching of uranium

    International Nuclear Information System (INIS)

    A process is described for the in-situ leaching of uranium-containing ores employing an acidic leach liquor containing peroxymonosulphuric acid. Preferably, additionally, sulphuric acid is present in the leach liquor. (author)

  14. Leaching of lead from zinc leach residue in acidic calcium chloride aqueous solution

    Science.gov (United States)

    Wang, Le; Mu, Wen-ning; Shen, Hong-tao; Liu, Shao-ming; Zhai, Yu-chun

    2015-05-01

    A process with potentially reduced environmental impacts and occupational hazards of lead-bearing zinc plant residue was studied to achieve a higher recovery of lead via a cost-effective and environmentally friendly process. This paper describes an optimization study on the leaching of lead from zinc leach residue using acidic calcium chloride aqueous solution. Six main process conditions, i.e., the solution pH value, stirring rate, concentration of CaCl2 aqueous solution, liquid-to-solid (L/S) ratio, leaching temperature, and leaching time, were investigated. The microstructure and components of the residue and tailing were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). On the basis of experimental results, the optimum reaction conditions were determined to be a solution pH value of 1, a stirring rate of 500 r·min-1, a CaCl2 aqueous solution concentration of 400 g·L-1, a liquid-to-solid mass ratio of 7:1, a leaching temperature of 80°C, and a leaching time of 45 min. The leaching rate of lead under these conditions reached 93.79%, with an iron dissolution rate of 19.28%. Silica did not take part in the chemical reaction during the leaching process and was accumulated in the residue.

  15. Kinetic study on pressure leaching of high iron sphalerite concentrate

    Institute of Scientific and Technical Information of China (English)

    XIE Ke-qiang; YANG Xian-wan; WANG Ji-kun; YAN Jiang-feng; SHEN Qing-feng

    2007-01-01

    The kinetics of pressure leaching high iron sphalerite concentrate was studied. The effects of agitation rate, temperature, oxygen partial pressure, initial acid concentration, particle size, iron content in the concentrate and concentration of Fe2+ added into the solution on the leaching rate of zinc were examined. The experiment results indicate that if the agitation rate is greater than 600 r/min, its influence on Zn leaching rate is not substantial. A suitable rise in temperature can facilitate the leaching reaction, and the temperature should be controlled at 140-150 ℃. The increase trend of Zn leaching rate becomes slow when pressure is greater than 1.2 MPa, so the pressure is controlled at 1.2-1.4 MPa. Under the conditions of this study, Zn leaching rate decreases with a rise in the initial sulfuric acid concentration; and Zn leaching rate increases with a rise of iron content in the concentrate and Fe2+ concentration in the solution. Moreover, the experiment demonstrates that the leaching process follows the surface chemical reaction control kinetic law of "shrinking of unreacted core". The activation energy for pressure leaching high iron sphalerite concentrate is calculated, and a mathematical model for this pressure leaching is obtained. The model is promising to guide the practical operation of pressure leaching high iron sphalerite concentrate.

  16. Geochemical association of Pu and Am in selected host-phases of contaminated soils from the UK and their susceptibility to chemical and microbiological leaching

    International Nuclear Information System (INIS)

    Understanding the biogeochemical behaviour and potential mobility of actinides in soils and groundwater is vital for developing remediation and management strategies for radionuclide-contaminated land. Pu is known to have a high Kd in soils and sediments, however remobilization of low concentrations of Pu remains a concern. Here, some of the physicochemical properties of Pu and the co-contaminant, Am, are investigated in contaminated soils from Aldermaston, Berkshire, UK, and the Esk Estuary, Cumbria, UK, to determine their potential mobility. Sequential extraction techniques were used to examine the host-phases of the actinides in these soils and their susceptibility to microbiological leaching was investigated using acidophilic sulphur-oxidising bacteria. Sequential extractions found the majority of 239,240Pu associated with the highly refractory residual phase in both the Aldermaston (63.8–85.5 %) and Esk Estuary (91.9–94.5%) soils. The 241Am was distributed across multiple phases including the reducible oxide (26.1–40.0%), organic (45.6–63.6%) and residual fractions (1.9–11.1%). Plutonium proved largely resistant to leaching from microbially-produced sulphuric acid, with a maximum 0.18% leached into solution, although up to 12.5% of the 241Am was leached under the same conditions. If Pu was present as distinct oxide particles in the soil, then 241Am, a decay product of Pu, would be expected to be physically retained in the particle. The differences in geochemical association and bioleachability of the two actinides suggest that this is not the case and hence, that significant Pu is not present as distinct particles. These data suggest the majority of Pu in the contaminated soils studied is highly recalcitrant to geochemical changes and is likely to remain immobile over significant time periods, even when challenged with aggressive “bioleaching” bacteria. - Highlights: • Pu in the contaminated soils is associated with the recalcitrant residual

  17. Manual of acid in situ leach uranium mining technology

    International Nuclear Information System (INIS)

    In situ leaching (ISL) technology recovers uranium using two alternative chemical leaching systems - acid and alkaline. This report brings together information from several technical disciplines that are an essential part of ISL technology. They include uranium geology, geohydrology, chemistry as well as reservoir engineering and process engineering. This report provides an extensive description of acid ISL uranium mining technology

  18. Modeling rejection immunity

    Directory of Open Access Journals (Sweden)

    Gaetano Andrea De

    2012-05-01

    Full Text Available Abstract Background Transplantation is often the only way to treat a number of diseases leading to organ failure. To overcome rejection towards the transplanted organ (graft, immunosuppression therapies are used, which have considerable side-effects and expose patients to opportunistic infections. The development of a model to complement the physician’s experience in specifying therapeutic regimens is therefore desirable. The present work proposes an Ordinary Differential Equations model accounting for immune cell proliferation in response to the sudden entry of graft antigens, through different activation mechanisms. The model considers the effect of a single immunosuppressive medication (e.g. cyclosporine, subject to first-order linear kinetics and acting by modifying, in a saturable concentration-dependent fashion, the proliferation coefficient. The latter has been determined experimentally. All other model parameter values have been set so as to reproduce reported state variable time-courses, and to maintain consistency with one another and with the experimentally derived proliferation coefficient. Results The proposed model substantially simplifies the chain of events potentially leading to organ rejection. It is however able to simulate quantitatively the time course of graft-related antigen and competent immunoreactive cell populations, showing the long-term alternative outcomes of rejection, tolerance or tolerance at a reduced functional tissue mass. In particular, the model shows that it may be difficult to attain tolerance at full tissue mass with acceptably low doses of a single immunosuppressant, in accord with clinical experience. Conclusions The introduced model is mathematically consistent with known physiology and can reproduce variations in immune status and allograft survival after transplantation. The model can be adapted to represent different therapeutic schemes and may offer useful indications for the optimization of

  19. Heat rejection system

    Science.gov (United States)

    Smith, Gregory C.; Tokarz, Richard D.; Parry, Jr., Harvey L.; Braun, Daniel J.

    1980-01-01

    A cooling system for rejecting waste heat consists of a cooling tower incorporating a plurality of coolant tubes provided with cooling fins and each having a plurality of cooling channels therein, means for directing a heat exchange fluid from the power plant through less than the total number of cooling channels to cool the heat exchange fluid under normal ambient temperature conditions, means for directing water through the remaining cooling channels whenever the ambient temperature rises above the temperature at which dry cooling of the heat exchange fluid is sufficient and means for cooling the water.

  20. Underground leaching of uranium ores

    International Nuclear Information System (INIS)

    Large amounts of low-grade U ore, not worth processing by conventional methods, are to be found at many sites in mine pillars, walls, and backfilling. Many proven deposits are not being mined because the geological conditions are difficult or the U ore is of relatively low grade. Factors such as radioactive emission, radon emanation, and the formation of radioactive dust give rise to health hazards. When U ores are treated above ground, enormous quantities of solid and liquid radioactive waste and mining spoil accumulate. The underground leaching of U is a fundamentally different kind of process. It is based on the selective dissolving of U at the place where it occurs by a chemical reagent; all that reaches the ground surface is a solution containing U, and after extraction of the U by sorption the reagent is used again. The main difficult and dangerous operations associated with conventional methods (excavation; extraction and crushing of the ore; storage of wastes) are avoided. Before underground leaching the ore formation has to be fractured and large ore bodies broken down into blocks by shrinkage stopping. These operations are carried out by advanced machinery and require the presence underground of only a few workers. If the ore is in seams, the only mining operation is the drilling of boreholes. The chemical reagent is introduced under pressure through one set of boreholes, while the U bearing solution is pumped out from another set. The process is monitored with the help of control boreholes. After extraction of the U by sorption, the reagent is ready to be used again. Very few operations are involved and insignificant amounts of dissolved U escape into the surrounding rock formations. Experience has shown that underground leaching reduces the final cost of the U metal, increases productivity, reduces capital expenditure, and radically improves working conditions

  1. Kinetic process of oxidative leaching of chalcopyrite under low oxygen pressure and low temperature

    Institute of Scientific and Technical Information of China (English)

    QIU Ting-sheng; NIE Guang-hua; WANG Jun-feng; CUI Li-feng

    2007-01-01

    Kinetic process of oxidative leaching of chalcopyrite in chloride acid hydroxide medium under oxygen pressure and low temperature was investigated. The effect on leaching rate of chalcopyrite caused by these factors such as ore granularity, vitriol concentration, sodium chloride concentration, oxygen pressure and temperature was discussed. The results show that the leaching rate of chalcopyrite increases with decreasing the ore granularity. At the early stage of oxidative reaction, the copper leaching rate increases with increasing the oxygen pressure and dosage of vitriol concentration, while oxygen pressure affects leaching less at the later stage. At low temperature, the earlier oxidative leaching process of chalcopyrite is controlled by chemical reactions while the later one by diffusion. The chalcopyrite oxidative leaching rate has close relation with ion concentration in the leaching solution. The higher ion concentration is propitious for chalcopyrite leaching.

  2. Study of radionuclide leaching from the residues of K Basin sludge dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Bechtold, D.B.

    1998-07-30

    The sludges remaining in the K Basins after removal of the spent N Reactor nuclear fuel will be conditioned for disposal. After conditioning, an acid-insoluble residue will remain that may require further leaching to properly condition it for disposal. This document presents a literature study to identify and recommend one or more chemical leaching treatments for laboratory testing, based on the likely compositions of the residues. The processes identified are a nitric acid cerate leach, a silver-catalyzed persulfate leach, a nitric hydrofluoric acid leach, an oxalic citric acid reactor decontamination leach, a nitric hydrochloric acid leach, a ammonium fluoride nitrate leach, and a HEOPA formate dehydesulfoxylate leach. All processes except the last two are recommended for testing in that order.

  3. Uranium in situ leaching

    International Nuclear Information System (INIS)

    Despite the depressed situation that has affected the uranium industry during the past years, the second Technical Committee Meeting on Uranium In Situ Leaching, organized by the International Atomic Energy Agency and held in Vienna from 5 to 8 October 1992, has attracted a relatively large number of participants. A notable development since the first meeting was that the majority of the contributions came from the actual operators of in situ leaching uranium production. At the present meeting, presentations on operations in the USA were balanced by those of the eastern European and Asian countries. Contributions from Bulgaria, China, Czechoslovakia, Germany (from the operation in the former German Democratic Republic), the Russian Federation and Uzbekistan represent new information not commonly available. In situ leach mining is defined in one of the paper presented as a ''mining method where the ore mineral is preferentially leached from the host rock in place, or in situ, by the use of leach solutions, and the mineral value is recovered. Refs, figs and tabs

  4. Chemical analysis and assessment of the heavy metal pollution in the sewage sludge and leaching solution%污水污泥及其浸出液重金属污染的化学分析与评价

    Institute of Scientific and Technical Information of China (English)

    李娟英; 陈洁芸; 沈燕萍; 石恺柘; 郑健; 柯友章; 何培民

    2013-01-01

    The present article is engaged in a chemical analysis and assessment of the heavy metal pollution in the sewage sludge and leaching solution.For this purpose,we have analyzed in this paper the general characteristics as well as the actual content and speciation of heavy metals in the dehydrated sludge samples from eight sewage processing plants in Shanghai with our leaching tests including HJ 557-2010,NEN 7341:1994,US TCLP and EN 12457-3:2002.The results of our analysis indicate that the total content of Zn and Cu in all the sludge samples are rather high,followed by Pb,As,Cd and Hg.Among the heavy metal contents,Cd reveals the highest degree of mobility from what is extracted in the water soluble.Cd also proves exchangeable,carbonate-precipitated and oxidation-bounded.It tends to be highly mobile and potentially bio-available,which therefore accounts for a higl percentage (70%).Of all the above four unstable fractions,Zn accounted for 20%-50%,which means that the considerable amount of Zn could be released to the liquid phase.Cu proves to be mainly present in the organic compounds with sulfide and therefore poor in mobility.The results from our leaching tests also indicate that the leaching amount of Zn was the greatest and followed by Cu and Pb,with As,Hg and Cd being the least.It is more worthwhile commenting that the leaching test of NEN 7341:1994 is the most attractive for its greatest leaching amount of heavy metals,followed by the other two roughly the same tests,that is,US TCLP and EN 12457-3:2002,though HJ 557-2010 proposed by China proves to be the most gentle one.The difference among the above leaching tests is related to the parameters of leachants,ratios of liquid to solid,oscillation modes and so on commonly adopted in the different tests.Though all the sludge samples were excluded from the hazardous wastes according to the current standard implemented in China,it remains logic and reasonable to categorize all the above samples into hazardous

  5. Measurement of leached hulls

    International Nuclear Information System (INIS)

    Leached hulls are the short lengths of fuel rod cladding and fuel element hardware which constitute a major waste product of a reprocessing plant employing a chop-and-leach head-end process. The small, undissolved fuel residue (0.1 to 1.0% of original fuel content) which is discarded with this waste must be measured for safeguards, material accountability, and process control reasons. This report gives a critical analysis of hull measurement techniques involving the analysis of fission product gamma rays, spontaneous fission neutrons from curium, and delayed neutron activation. Major emphasis is given to the measurement of 2186-keV gamma rays from 144Ce--144Pr. A detailed description of typical leached hull characteristics is presented at the beginning of the report. An extensive review of experience gained from existing hull measurement systems in the United Kingdom, France, Japan, Germany, Italy, and the United States is presented

  6. Electrogenerative leaching of nickel sulfide concentrate with ferric chloride

    Institute of Scientific and Technical Information of China (English)

    王少芬; 方正; 王云燕; 陈阳国

    2004-01-01

    In order to utilize the chemical energy in hydrometallurgical process of sulfide minerals reasonably and to simplify the purifying process, the electrogenerative process was applied and a dual cell system was introduced to investigate FeCl3 leaching of nickel sulfide concentrate. Some factors influencing the electrogenerative leaching, such as electrode structure, temperature and solution concentration were studied. The results show that a certain quantity of electrical energy accompanied with the leached products can be acquired in the electrogenerative leaching process.The output current and power increase with the addition of acetylene black to the electrode. Varying the components of electrode just affects the polarization degree of anode. Increasing FeCl3 concentration results in a sharp increase in the output of the leaching cell when c(FeCl3) is less than 0.1 mol/L. The optimum value of NaCl concentration for electrogenerative leaching nickel sulfide concentrate with FeCl3 is 3.0 mol/L. Temperature influences electrogenerative leaching by affecting anodic and cathodic polarization simultaneously. The apparent activation energy is determined to be 34.63 kJ/mol in the range of 298 K to 322 K. The leaching rate of Ni2+ is 29.3% after FeCl3 electrogenerative leaching of nickel sulfide concentrate for 620 min with a filter bag electrode.

  7. Leaching of Pyrites of Various Reactivities by Thiobacillus ferrooxidans

    OpenAIRE

    Baldi, Franco; Clark, Thomas; Pollack, S. S.; Olson, Gregory J.

    1992-01-01

    Wide variations were found in the rate of chemical and microbiological leaching of iron from pyritic materials from various sources. Thiobacillus ferrooxidans accelerated leaching of iron from all of the pyritic materials tested in shake flask suspensions at loadings of 0.4% (wt/vol) pulp density. The most chemically reactive pyrites exhibited the fastest bioleaching rates. However, at 2.0% pulp density, a delay in onset of bioleaching occurred with two of the pyrites derived from coal source...

  8. Rejection sampling in demand systems

    OpenAIRE

    Ley, Eduardo; Mark F.J. Steel

    1992-01-01

    We illustrate the method of rejection sampling in a Bayesian application of a new approach toı estimating Demand Systems. This approach, suggested by Varian (1990), is based on a generalization of Afriat's (1967) efficiency index. Rejection sampling is applied to the prior-to-posterior mapping enabling us to obtain posterior results in a nonstandard model.

  9. Radionuclide diagnosis of allograft rejection

    Energy Technology Data Exchange (ETDEWEB)

    George, E.A.

    1982-10-01

    Interaction with one or more anatomical and physiopathological characteristics of the rejecting renal allograft is suggested by those radioagents utilized specifically for the diagnosis of allograft rejection. Rejection, the most common cause of declining allograft function, is frequently mimicked clinically or masked by other immediate or long term post transplant complications. Understanding of the anatomical pathological features and kinetics of rejection and their modification by immunosuppressive maintenance and therapy are important for the proper clinical utilization of these radioagents. Furthermore, in selecting these radionuclides, one has to consider the comparative availability, preparatory and procedural simplicity, acquisition and display techniques and the possibility of timely report. The clinical utilities of radiofibrinogen, /sup 99m/Tc sulfur colloid and /sup 67/Ga in the diagnosis of allograft rejection have been evaluated to a variable extent in the past. The potential usefulness of the recently developed preparations of /sup 111/In labeled autologous leukocytes and platelets are presently under investigation.

  10. In-situ uranium leaching

    International Nuclear Information System (INIS)

    This invention provides a method for improving the recovery of mineral values from ore bodies subjected to in-situ leaching by controlling the flow behaviour of the leaching solution. In particular, the invention relates to an in-situ leaching operation employing a foam for mobility control of the leaching solution. A foam bank is either introduced into the ore bed or developed in-situ in the ore bed. The foam then becomes a diverting agent forcing the leaching fluid through the previously non-contacted regions of the deposit

  11. Physic-chemical evaluation of leach and water from the Borba Gato streamlet within the catchment area of the urban waste landfill of Maringá, Paraná State, Brazil - doi: 10.4025/actascitechnol.v34i1.6771

    Directory of Open Access Journals (Sweden)

    Marta Eliane Echeverria Borges

    2011-11-01

    Full Text Available The physic-chemical characteristics of leach deposited in the landfill waste pond and of water from the Borba Gato streamlet are evaluated. Twenty-six physic-chemical parameters were analyzed from three collection sites, or rather, two in the streamlet, one upstream (P-01 and one downstream (P-02 of the landfill waste pond, and one in the leach deposit pond (P-03. The streamlet area under analysis was impacted due to being in an agricultural area and for its urban waste deposits. Parameter concentrations of aluminum, iron and mercury were reported above the quality standard of freshwater, according to Conama 357/2005 resolution (class 2. Further, throughout the rainy period, the ammoniac nitrogen content was above the resolution quality standard for fresh water. Moreover, landfill leach was above standards of effluent discharge established by Conama 357/2005. An efficient treatment for the effluent generated in Maringá is required since there is evidence of leach pollution of the Borba Gato streamlet.

  12. Evaluation of the effectiveness of the filtration leaching for uranium recovery from uranium ore

    OpenAIRE

    Bolat Uralbekov; Mukhambetkaly Burkitbayev; Bagdat Satybaldiev

    2015-01-01

    The physical and chemical processes taking place in filtration leaching of uranium from uranium ore sample by sulphuric acid solution have been studied by modern physico-chemical methods (X-ray diffraction, scanning electron spectroscopy, electron probe microanalysis, optical emission spectroscope, ICP OES). Column leaching test was carried out for ore samples obtained from a uranium in-situ leaching (ISL) mining site using deluted sulphuricacid to study the evolution of various elements conc...

  13. Gold and Silver Extraction from Leach Solutions

    Directory of Open Access Journals (Sweden)

    Bagdaulet K. Kenzhaliyev

    2014-03-01

    Full Text Available There has been carried out an investigation on the extraction of gold and silver from thiosulfate solutions: standard test and technological solutions of chemical and electrochemical leaching. The influence of related metals on the process of extracting gold from solution was studied. There has been conducted a comparative study of the IR spectra of solutions after the sorption of gold, silver and related metals.

  14. Leaching of Carbothermic Reduced Titanium-bearing Blast Furnace Slag by Acid

    Institute of Scientific and Technical Information of China (English)

    ZHEN Yulan; ZHANG Guohua; CHOU Kuochih

    2016-01-01

    The kinetics of the leaching of carbothermic reduced titanium-bearing blast furnace slag in Panzhihua Iron and Steel Company with acid system under atmosphere pressure was studied. The results show that the temperature and concentration have significant influence on leaching of carbothermic reduced titanium-bearing blast furnace slag by ac-id. The experimental data of leaching indicate that the shrinking core model with chemical reaction controlled process is most applicable for the acid leaching. The apparent activation energy can be estimated to be from 23 to 32 kJ/mol. Fur-thermore, the main products are TiC and SiO2 after leaching.

  15. A method for the concentration of fine-grained rutile (TiO2) from sediment and sedimentary rocks by chemical leaching

    Science.gov (United States)

    Commeau, Judith A.; Valentine, Page C.

    1991-01-01

    Quaternary marine sediment in the Gulf of Maine basins contains 0.7 to 1.0 wt percent TiO2 (determined by X-ray fluorescence spectrometry). Most of this TiO2 exists in the form of silt-size rutile crystals that are visible by using the petrographic microscope with transmitted light (Valentine and Commeau, 1990). The identification of rutile was confirmed by using a scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectrometer (EDS) system. To quantify the amount of TiO2 in the sediment contributed by rutile and its polymorphs, anatase and brookite, it was necessary to eliminate as many of the other minerals as possible, especially titanium-bearing minerals such as ilmenite, ilmenomagnetite, biotite, hornblende, oyroxene, and sphene. We accomplished this by developing a method of chemical dissolution that removed the bulk of the raw material and left the TiO2 minerals intact.

  16. Soil column leaching of pesticides.

    Science.gov (United States)

    Katagi, Toshiyuki

    2013-01-01

    persistence (DT50) of the pesticide, and its sorption/desorption(Koc) characteristics. These parameters may vary for the same pesticide from geographic site-to-site and with soil depth. The interactions that normally occur between pesticides and dissolved organic matter (DOM) or WDC are yet other factors that may complicate pesticide leaching behavior.The soil mobility of pesticides is normally tested both in the laboratory and in the field. Lab studies are initially performed to give researchers a preliminary appraisal of the relative mobility of a pesticide. Later, field lysimeter studies can be performed to provide more natural leaching conditions that emulate the actual field use pattern. Lysimeter studies give the most reliable information on the leaching behavior of a pesticide under field conditions, but these studies are time-consuming and expensive and cannot be performed everywhere. It is for this reason that the laboratory soil column leaching approach is commonly utilized to profile the mobility of a pesticide,and appraise how it behaves in different soils, and relative to other pesticides.Because the soil structure is chemically and physically heterogenous, different pesticide tests may produce variable DT50 and Koc values; therefore, initial pesticide mobility testing is undertaken in homogeneously packed columns that contain two or more soils and are eluted at constant flow rates. Such studies are done in duplicate and utilize a conservative tracer element. By fitting an appropriate mathematical model to the breakthrough curve of the conservative tracer selected,researchers determine key mobility parameters, such as pore water velocity, the column-specific dispersion coefficient, and the contribution of non equilibrium transport processes. Such parameters form the basis for estimating the probable transport and degradation rates that will be characteristic of the tested pesticide. Researchers also examine how a pesticide interacts with soil DOM and WDC, and

  17. Variable Heat Rejection (VHR) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop advanced technologies to enable a variable heat rejection Thermal Control System (TCS) capable of operating through a wide range of thermal environments...

  18. Transplant rejection in terrestrial molluscs

    Directory of Open Access Journals (Sweden)

    E Furuta

    2011-01-01

    Full Text Available To know whether or not molluscs are capable of recognizing tissue allo-antigens, dorsal skin-allografts were exchanged between adult terrestrial slug, Incilaria fruhstorferi. We succeeded for the first time in orthotopic transplantation of allografts and observed chronic rejection of allografts. Cellular changes in the rejection process continued over for 40 days. Two functional types of “effector” cells were recognized at the rejection site, but they were observed to be macrophages possessing perforin granules and phagocytosing damaged cells of the allograft. Three days after transplantation, the perforin-positive cells were recognized only in the recipient tissue surrounding the allograft. Five days after transplantation, these cells started to appear in the graft, while they disappeared from the host tissue. However, TUNEL-positive cells (apoptotic cells were not observed throughout the graft-rejection process. Electron microscopic examination of the graft tissue revealed autophagic degeneration of epithelial cells, mucous cells, pigment cells, fibroblasts, and muscle cells. These observations suggest that the slugs have the capability to recognize differences in cell-surface molecules between the allogeneic and recipient tissue, and that an allograft is chronically rejected due to a type of immunocyte (macrophage that can induce perforin-dependent cell death

  19. Leaching Test Relationships, Laboratory-to-Field Comparisons and Recommendations for Leaching Evaluation using the Leaching Environmental Assessment Framework (LEAF)

    Science.gov (United States)

    This report presents examples of the relationships between the results of laboratory leaching tests, as defined by the Leaching Environmental Assessment Framework (LEAF) or analogous international test methods, and leaching of constituents from a broad range of materials under di...

  20. Leaching behavior of butanedionedioxime as gold ligand

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Butanedionedioxime, a small organic compound with low-toxicity and good chemical stability, has been proposed as an effective gold ligand in gold extraction. The result of experiment shows that: 1) highly effective gold lixiviantcan be composed of butanedionedioxime (BDM) with many oxidants, especially potassium permanganate; 2)in the leaching system of BD M- K M nO4 the suitable Ox/Lig(ratio of oxidants to gold ligands) tange is 0.20 ~ 0. 50, optimally 0.25 ~0.45 at the pH range of 7 ~ 11; 3) BDM-KMnO4 extraction of gold from an oxide ore is similar to cyanide(cyanide-O2)extraction, but the leaching rate of gold by BDM-KMnO4 is faster than that by cyanide-O2; 4) gold may readily be recov-ered by carbon adsorption and zinc precipitation

  1. Sulfuric acid leaching kinetics of South African chromite

    Institute of Scientific and Technical Information of China (English)

    Qing Zhao; Cheng-jun Liu; Pei-yang Shi; Bo Zhang; Mao-fa Jiang; Qing-song Zhang; Ron Zevenhoven; Henrik Saxn

    2015-01-01

    The sulfuric acid leaching kinetics of South African chromite was investigated. The negative influence of a solid product layer constituted of a silicon-rich phase and chromium-rich sulfate was eliminated by crushing the chromite and by selecting proper leaching con-ditions. The dimensionless change in specific surface area and the conversion rate of the chromite were observed to exhibit a proportional re-lationship. A modified shrinking particle model was developed to account for the change in reactive surface area, and the model was fitted to experimental data. The resulting model was observed to describe experimental findings very well. Kinetics analysis revealed that the leach-ing process is controlled by a chemical reaction under the employed experimental conditions and the activation energy of the reaction is 48 kJ·mol–1.

  2. Coupling leaching of sphalerite concentrate

    Institute of Scientific and Technical Information of China (English)

    彭鹏; 谢惠琴; 卢立柱

    2004-01-01

    Coupling process of sphalerite concentrate leaching in H2 SO4-HNO3 and tetrachloroethylene extracting of sulfur was investigated. Effects of leaching temperature, leaching time, mass ratio of liquid to solid and tetrachloroethylene addition on zinc leaching processes were examined separately. SEM images of sphalerite concentrate and residues were performed by using JEM-6700F field emission scanning electron microscope. The relationship between the number of recycling and extraction ratio of zinc was studied. The results indicate that 99.6 % zinc is obtained after leaching for 3 h at 85 ℃ and pressure of 0.1 MPa O2, with 20 g sphalerite concentrate in 200 mL leaching solution containing 2.0 mol/L H2SO4 and 0.2 mol/L HNO3, in the presence of 10 mL C2Cl4. The leaching time of zinc is 50% shorter than that in the common leaching. The coupling effect is distinct. The recycled C2Cl4 exerts little influence on extraction ratio of zinc.

  3. Diagnosis and Treatment of Pancreas Rejection

    OpenAIRE

    Redfield, R. R.; Kaufman, D. B.; Odorico, J. S.

    2015-01-01

    Despite significant improvement in pancreas allograft survival, rejection of the pancreas remains a major clinical problem. In addition to cellular rejection of the pancreas, antibody-mediated rejection of the pancreas is now a well-described entity. The 2011 Banff update established comprehensive guidelines for the diagnosis of acute and chronic AMR. The pancreas biopsy is critical in order to accurately diagnose and treat pancreas rejection. Other modes of monitoring pancreas rejection we f...

  4. Nitrogen Leaching in Vegetable Fields in the Suburbs of Shanghai

    Institute of Scientific and Technical Information of China (English)

    CAO Lin-Kui; CHEN Guo-Jun; LU Yi-Tong

    2005-01-01

    Nitrogen (N) leaching in vegetable fields from December 2002 to May 2003 with equal dressings of total N for a sequential rotation of Chinese flat cabbage (Brassica chinensis L. var. rosularis) and lettuce (Lactuca sativa L.) in a suburban major vegetable production base of Shanghai were examined using the lysimeter method to provide a scientific basis for rational utilization of nitrogen fertilizers so as to prevent nitrogen pollution of water resources. Results showed that leached N consisted mainly of nitrate N, which accounted for up to more than 90% of the total N loss and could contribute to groundwater pollution. Data also showed that by partly substituting chemical N (30%) in a basal dressing with equivalent N of refined organic fertilizer in the Chinese fiat cabbage field, 64.5% of the leached nitrate N was reduced,while in the lettuce (Lactuca sativa L.) field, substituting 1/2 of the chemical N in a basal dressing and 1/3 of the chemical N in a top dressing with equivalent N of refined organic fertilizers reduced 46.6% of the leached nitrate N. In the two-year sequential rotation system of Chinese fiat cabbage and lettuce, nitrate-N leaching in the treatment with the highest amount of chemical fertilizer was up to 46.55 kg ha-1, while treatment plots with the highest amount of organic fertilizer had only 17.58 kg ha-1. Thus, partly substituting refined organic fertilizer for chemical nitrogen in the first two seasons has a great advantage of reducing nitrate-N leaching.

  5. Studies on Leaching of Heavy Metals from E – waste

    Directory of Open Access Journals (Sweden)

    Caroline Michael

    2013-12-01

    Full Text Available One of the global problems in the present day world is the negative impacts created by the growing e-waste on the natural resources like air, soil and water. In the present work, the discarded electronic components were allowed to leach in water samples drawn from different rivers and the leachate were analyzed for the presence of heavy metals. The results highlight that even if the contact time is short, the toxic elements tend to leach to a great extent. In our studies, Arsenic had leached to an extent of 0.053ppm, Cadmium 0.010 ppm, Chromium 0.029 ppm, Lead 0.042ppm and Mercury 0.061ppm. The results indicate that most of the metals have a tendency to leach and the extent of leaching depends on the quality of the water. As a result of leaching the physico-chemical parameters like pH, hardness, conductance and TDS of the water samples underwent a change. On the other hand, the physical parameters like viscosity, density, were not much affected. These studies highlight the danger of dumping the discarded electronic components in river beds especially when the water flow is less and when the water is stagnated.

  6. Evaluation of glass leaching as nutrient source for microalgae growth

    International Nuclear Information System (INIS)

    Three glasses with an elemental composition similar to the nutrient ratio required for Spirulina platensis growth and with different SiO2 content have been prepared. The glasses were crushed and sieved into 2 different fractions and the effect of the particle size has been studied in terms of the leaching kinetics of each element. The chemical analysis of the leaching water was used for obtaining the dissolution rate curves for each element taking part of the glass composition. From the calculation of the leaching rate constant and the exponential constant of the lixiviation reaction, it has been evaluated the Spirulina platensis growth in ambient normal conditions of light, temperature and pH of the growing media. It has been concluded that, either from the modification of the chemical composition of the glass or its particle size, it is possible to tune the delivery of the nutrients to match the growth rate of Spirulina platensis. (Author)

  7. Increasing silver leaching rate from leaching-resistant zinc residues by thiourea leaching method with pressurized preoxidation process

    Institute of Scientific and Technical Information of China (English)

    胡天觉; 曾光明; 黄国和; 袁兴中; 李建兵

    2003-01-01

    As for the leaching-resistant zinc residues, the silver leaching rate can be over 98% through the processof pressurized preoxidation and thiourea leaching. Compared with the method of extracting the silver directly fromthe leaching-resistant zinc residues, the silver leaching rate is greatly improved. The optimum preoxidation condi-tions are: particle size range 40 - 60 μm, oxygen partial pressure 106 Pa, temperature 80 - 90 ℃, pH= 1.0, andleaching time 5 h. After pretreatment, the time of thiourea leaching silver is shortened to 1.5 h, and the thioureaconsumption is reduced greatly. The oxidation mechanism and the thiourea leaching kinetics were also explored.

  8. Leach test of cladding removal waste grout using Hanford groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R.J.; Martin, W.J.; Legore, V.L.

    1995-09-01

    This report describes laboratory experiments performed during 1986-1990 designed to produce empirical leach rate data for cladding removal waste (CRW) grout. At the completion of the laboratory work, funding was not available for report completion, and only now during final grout closeout activities is the report published. The leach rates serve as inputs to computer codes used in assessing the potential risk from the migration of waste species from disposed grout. This report discusses chemical analyses conducted on samples of CRW grout, and the results of geochemical computer code calculations that help identify mechanisms involved in the leaching process. The semi-infinite solid diffusion model was selected as the most representative model for describing leaching of grouts. The use of this model with empirically derived leach constants yields conservative predictions of waste release rates, provided no significant changes occur in the grout leach processes over long time periods. The test methods included three types of leach tests--the American Nuclear Society (ANS) 16.1 intermittent solution exchange test, a static leach test, and a once-through flow column test. The synthetic CRW used in the tests was prepared in five batches using simulated liquid waste spiked with several radionuclides: iodine ({sup 125}I), carbon ({sup 14}C), technetium ({sup 99}Tc), cesium ({sup 137}Cs), strontium ({sup 85}Sr), americium ({sup 241}Am), and plutonium ({sup 238}Pu). The grout was formed by mixing the simulated liquid waste with dry blend containing Type I and Type II Portland cement, class F fly ash, Indian Red Pottery clay, and calcium hydroxide. The mixture was allowed to set and cure at room temperature in closed containers for at least 46 days before it was tested.

  9. Leaching Properties of Naturally Occurring Heavy Metals from Soils

    Science.gov (United States)

    Zhang, M.; Hoshino, M.; Yoshikawa, M.; Hara, J.; Sugita, H.

    2014-12-01

    The major threats to human health from heavy metals are associated with exposure to arsenic, lead, cadmium, chromium, mercury, as well as some other elements. The effects of such heavy metals on human health have been extensively studied and reviewed by international organizations such as WHO. Due to their toxicity, heavy metal contaminations have been regulated by national environmental standards in many countries, and/or laws such as the Soil Contamination Countermeasures Act in Japan. Leaching of naturally occurring heavy metals from the soils, especially those around abandoned metal mines into surrounding water systems, either groundwater or surface water systems, is one of the major pathways of exposure. Therefore, understanding the leaching properties of toxic heavy metals from naturally polluted soils is of fundamentally importance for effectively managing abandoned metal mines, excavated rocks discharged from infrastructure constructions such as tunneling, and/or selecting a pertinent countermeasure against pollution when it is necessary. In this study, soil samples taken from the surroundings of abandoned metal mines in different regions in Japan were collected and analyzed. The samples contained multiple heavy metals such as lead, arsenic and chromium. Standard leaching test and sequential leaching test considering different forms of contaminants, such as trivalent and pentavalent arsenics, and trivalent and hexavalent chromiums, together with standard test for evaluating total concentration, X-ray Fluorescence Analysis (XRF), X-ray diffraction analysis (XRD) and Cation Exchange Capacity (CEC) tests were performed. In addition, sequential leaching tests were performed to evaluate long-term leaching properties of lead from representative samples. This presentation introduces the details of the above experimental study, discusses the relationships among leaching properties and chemical and mineral compositions, indicates the difficulties associated with

  10. Preparation of manganese sulfate from low-grade manganese carbonate ores by sulfuric acid leaching

    Science.gov (United States)

    Lin, Qing-quan; Gu, Guo-hua; Wang, Hui; Zhu, Ren-feng; Liu, You-cai; Fu, Jian-gang

    2016-05-01

    In this study, a method for preparing pure manganese sulfate from low-grade ores with a granule mean size of 0.47 mm by direct acid leaching was developed. The effects of the types of leaching agents, sulfuric acid concentration, reaction temperature, and agitation rate on the leaching efficiency of manganese were investigated. We observed that sulfuric acid used as a leaching agent provides a similar leaching efficiency of manganese and superior selectivity against calcium compared to hydrochloric acid. The optimal leaching conditions in sulfuric acid media were determined; under the optimal conditions, the leaching efficiencies of Mn and Ca were 92.42% and 9.61%, respectively. Moreover, the kinetics of manganese leaching indicated that the leaching follows the diffusion-controlled model with an apparent activation energy of 12.28 kJ·mol-1. The purification conditions of the leaching solution were also discussed. The results show that manganese dioxide is a suitable oxidant of ferrous ions and sodium dimethyldithiocarbamate is an effective precipitant of heavy metals. Finally, through chemical analysis and X-ray diffraction analysis, the obtained product was determined to contain 98% of MnSO4·H2O.

  11. Feasibility study for an additional HEPA filter leaching system in NWCF

    International Nuclear Information System (INIS)

    This report documents the feasibility of installing a second high-efficiency particulate air (HEPA) filter leaching system in the New Waste Calcining Facility at the Idaho Chemical Processing Plant (ICPP). A large spent filter backlog already exists at the ICPP, and it has been uncertain whether the existing HEPA filter leaching system will have a throughput rate sufficient to work off the existing backlog in a timely manner. Three areas within the New Waste Calcining Facility (NWCF) have been identified as possible locations for a second filter leaching system. This report examines the suitability of each location, identifies modifications that would be necessary-to install a filter leaching system at each location, examines the impact of modifying each location, and discusses recent efforts to estimate filter throughput using the existing filter leaching system. Based on all available information, installation of a second filter leaching system is not recommended at the present time

  12. Peer Group Rejection and Children's Outgroup Prejudice

    Science.gov (United States)

    Nesdale, Drew; Durkin, Kevin; Maass, Anne; Kiesner, Jeff; Griffiths, Judith; Daly, Josh; McKenzie, David

    2010-01-01

    Two simulation studies examined the effect of peer group rejection on 7 and 9 year old children's outgroup prejudice. In Study 1, children (n = 88) pretended that they were accepted or rejected by their assigned group, prior to competing with a lower status outgroup. Results indicated that rejected versus accepted children showed increased…

  13. 7 CFR 58.136 - Rejected milk.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Rejected milk. 58.136 Section 58.136 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Milk § 58.136 Rejected milk. A plant shall reject specific milk from a producer if the milk fails...

  14. Leaching of Natural Gravel and Concrete by CO2 - Experimental Design, Leaching Behaviour and Dissolution Rates

    Science.gov (United States)

    Fuchs, Rita; Leis, Albrecht; Mittermayr, Florian; Harer, Gerhard; Wagner, Hanns; Reichl, Peter; Dietzel, Martin

    2015-04-01

    The durability of building material in aggressive aqueous environments is a key factor for evaluating the product quality and application as well as of high economic interest. Therefore, aspects of durability have been frequently investigated with different approaches such as monitoring, modelling and experimental work. In the present study an experimental approach based on leaching behaviour of natural calcite-containing siliceous gravel used as backfill material in tunnelling and sprayed concrete by CO2 was developed. CO2 was introduced to form carbonic acid, which is known as an important agent to induce chemical attack. The goals of this study were (i) to develop a proper experimental design to survey the leaching of building materials on-line, (ii) to decipher individual reaction mechanisms and kinetics and (iii) to estimate time-resolved chemical resistance of the used material throughout leaching. A combined flow through reactor unit was successfully installed, where both open and closed system conditions can be easily simulated by changing flow directions and rates. The chemical compositions of the experimental solutions were adjusted by CO2 addition at pHstat conditions and monitored in-situ by pH/SpC electrodes and by analysing the chemical composition of samples throughout an experimental run. From the obtained data e.g. dissolution rates with respect to calcite were obtained for the gravel material, which were dependent on the individual calcite content of the leached material. The rates were found to reflect the flow rate conditions, and the kinetic data lay within the range expected from dissolution experiments in the CaCO3-CO2-H2O system. In case of concrete the reactions throughout the leaching experiment were complex. Coupled dissolution and precipitation phenomena (e.g. portlandite dissolution, calcite formation) occurred. The coupled reactions can be followed by the evolution of the solution chemistry. The overall rates of elemental removal from

  15. Rejection mechanisms for contaminants in polymeric reverse osmosis membranes

    CERN Document Server

    Shen, Meng; Lueptow, Richard M

    2016-01-01

    Despite the success of reverse osmosis (RO) for water purification, the molecular-level physico-chemical processes of contaminant rejection are not well understood. Here we carry out NEMD simulations on a model polyamide RO membrane to understand the mechanisms of transport and rejection of both ionic and neutral contaminants in water. We observe that the rejection changes non-monotonously with ion sizes. In particular, the rejection of urea, 2.4 A radius, is higher than ethanol, 2.6 A radius, and the rejections for organic solutes, 2.2-2.8 A radius, are lower than Na+, 1.4 A radius, or Cl-, 2.3 A radius. We show that this can be explained in terms of the solute accessible intermolecular volume in the membrane and the solute-water pair interaction energy. If the smallest open spaces in the membrane's molecular structure are all larger than the hydrated solute, then the solute-water pair interaction energy does not matter. However, when the open spaces in the polymeric structure are such that solutes have to s...

  16. Leaching of heavy metals from steelmaking slags

    Directory of Open Access Journals (Sweden)

    Gomes, J. F. P

    2006-12-01

    Full Text Available Leaching tests with EAF and Ladle slags were performed, using a flow through test and the standard batch test DIN 38414-S4. The previous method was used to simulate the leaching behaviour of steel slags under landfill. The chemical analysis of the leachates during this period shows, in general, for both types of slag, an increase of heavy metal releases with ageing. Standard test method DIN 38414-S4 was used to evaluate leachability of heavy metals by water in unprocessed slags. After more than one year of trials, slag samples submitted to these trials presented very low total leaching levels. The most extracted elements are calcium and magnesium. Nevertheless, in flow-through test, calcium and magnesium leached from solid slags are below 0.5% and all other metals below 0.1%. Leachates obtained with DIN 38414-S4 present, as expected, higher leaching values; however, these are inferior to 5 % (Ca and 1% (other elements.

    Este articulo contiene los resultados obtenidos en ensayos de lixiviación de escorias de acero (horno electrico y cuchara ejecutados siguiendo la metodologia de flujo dinámico así como el ensayo normalizado DIN 38414-S4. El primer ensayo intenta simular el comportamiento de lixiviación de las escorias en vertedero. Para las escorias ensayadas se han complementado los ensayos con el análisis químico de los lixiviados y se ha verificado un aumento de la liberación de metales pesados. El ensayo DIN 38414-S4 se ha utilizado para evaluar la lixiviación por agua de metales pesados, en muestras de escorias originales. Despues de un año de ensayos, se han observado niveles muy bajos de lixiviación. Los elementos mas lixiviados han sido calcio y magnesio. No obstante, en los ensayos de flujo dinámico, el calcio y el magnesio lixiviados de las escorias sólidas era menor de 0,5% y el resto de los otros metales era inferior a 0,1%. Los lixiviados obtenidos con el ensayo DIN 38414-S4 presentan, como era de esperar, valores

  17. A Simulator for Copper Ore Leaching

    Energy Technology Data Exchange (ETDEWEB)

    Travis, B.

    1999-05-14

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Copper is a strategic metal and the nation needs a secure supply both for industrial use and military needs. However, demand is growing worldwide and is outstripping the ability of the mining industry to keep up. Improved recovery methods are critically needed to maintain the balance of supply and demand. The goal of any process design should be to increase the amount of copper recovered, control movement of acid and other environmentally harmful chemicals, and reduce energy requirements. To achieve these ends, several improvements in current technology are required, the most important of which is a better understanding of, and the ability to quantify, how fluids move through heterogeneous materials in a complex chemical environment. The goal of this project is create a new modeling capability that couples hydrology with copper leaching chemistry . once the model has been verified and validated, we can apply the model to specific problems associated with heap leaching (flow channeling due to non-uniformities in heap structure, precipitation/dissolution reactions, and bacterial action), to understand the causes of inefficiencies, and to design better recovery systems. We also intend to work with representatives of the copper mining industry to write a coordinated plan for further model development and application that will provide economic benefits to the industry and the nation.

  18. Ferrite grade iron oxides from ore rejects

    Indian Academy of Sciences (India)

    K S Rane; V M S Verenkar; P Y Sawant

    2001-06-01

    Iron oxyhydroxides and hydroxides were synthesized from chemically beneficiated high SiO2/Al2O3 low-grade iron ore (57.49% Fe2O3) rejects and heated to get iron oxides of 96–99.73% purity. The infrared band positions, isothermal weight loss and thermogravimetric and chemical analysis established the chemical formulas of iron-oxyhydroxides as -FeOOH.0.3H2O; -FeOOH.0.2H2O and amorphous FeOOH. The thermal products of all these were -Fe2O3 excepting that of -FeOOH.0.3H2O which gave mainly -Fe2O3 and some admixture of -Fe2O3. The hydrazinated iron hydroxides and oxyhydroxides, on the other hand, decomposed autocatalytically to mainly -Fe2O3. Hydrazine method modifies the thermal decomposition path of the hydroxides. The saturation magnetization, s, values were found to be in the range 60–71 emu g–1 which are close to the reported values for -Fe2O3. Mechanism of the -Fe2O3 formation by hydrazine method is discussed.

  19. Study on Chemical Speciation of Uranium in Samples from in-situ Leaching Sandstone-type Uranium Deposit in Xinjiang%新疆某地浸砂岩型铀矿中铀赋存形态的研究

    Institute of Scientific and Technical Information of China (English)

    马强; 冯志刚; 孙静; 谢二举; 李小军

    2012-01-01

    This paper presents a method of studying uranium speciation from in-situ leaching sandstone-type uranium deposits by a sequential extraction procedure and demonstrates its application to sandstone uranium exploration. The chemical extraction procedure was modified from Tessier. Uranium in samples was classified into five speciations: exchangeable ions, bound to carbonates, bound to Fe-Mn oxides, bound to sulfide-organic matter and residual speciation. The first four phases consisted of active uranium with the residual uranium being stable uranium. The results show that the uranium distribution characteristics were significantly different whether they were in different samples or in the same sample. The average amounts of residual speciation, carbonates speciation, exchangeable speciation, sulfide-organic matter speciation and Fe-Mn speciation decreased in order as 37. 75% (RSD = 1. 80% ), 20. 56% (RSD = 2. 72%), 15. 51% ( RSD = 1. 85% ), 14. 26% ( RSD = 2. 08% ) and 11.91% ( RSD = 1.75% ) , respectively. According to the present technology of acid dipped processing, the active uranium was teachable and the inert uranium was unleachable. This study indicates that residual speciation is the primary component. The uranium extraction rate for uranium ore with a high proportion of residual uranium ( such as the No.4 sample with 57.17% residual uranium in this paper) is lower and the extraction rale does not increase significantly by improving the dissolve acidity and oxidants.%以新疆某地浸砂岩型铀矿为研究对象,参考Tessier逐级化学提取方法,对10件矿芯试样进行铀赋存形态的研究.将铀赋存形态分为可交换离子态、碳酸盐结合态、铁锰氧化物结合态、硫化物及有机物结合态和残渣态,其中前4种形态铀为活性铀,残渣态铀为惰性铀.研究结果显示,无论是试样间还是同一试样内,铀的形态分布特征都存在明显的差异.各形态铀的含量(平均值)

  20. Leaching of Zinc Sulfide by Thiobacillus ferrooxidans: Bacterial Oxidation of the Sulfur Product Layer Increases the Rate of Zinc Sulfide Dissolution at High Concentrations of Ferrous Ions

    OpenAIRE

    Fowler, T. A.; Crundwell, F. K.

    1999-01-01

    This paper reports the results of leaching experiments conducted with and without Thiobacillus ferrooxidans at the same conditions in solution. The extent of leaching of ZnS with bacteria is significantly higher than that without bacteria at high concentrations of ferrous ions. A porous layer of elemental sulfur is present on the surfaces of the chemically leached particles, while no sulfur is present on the surfaces of the bacterially leached particles. The analysis of the data using the shr...

  1. Modeling of RO/NF membrane rejections of PhACs and organic compounds: a statistical analysis

    Directory of Open Access Journals (Sweden)

    G. Amy

    2008-07-01

    Full Text Available Rejections of pharmaceutical compounds (Ibuprofen, Diclofenac, Clofibric acid, Naproxen, Primidone, Phenacetin and organic compounds (Dichloroacetic acid, Trichloroacetic acid, Chloroform, Bromoform, Trichloroethene, Perchloroethene, Carbontetrachloride, Carbontetrabromide by NF (Filmtec, Saehan and RO (Filmtec, Saehan, Toray, Koch membranes were studied. Chloroform presented the lowest rejection due to small molar volume, equivalent width and length. Diclofenac and Primidone showed high rejections related to high molar volume and length. Dichloroacetic acid and Trichloroacetic acid presented good rejections caused by charge exclusion instead of steric hindrance mechanism influencing rejection. Bromoform and Trichloroethene showed low rejections due to small length and equivalent width. Carbontetrabromide, Perchloroethene and Carbontetrachloride with higher equivalent width than BF and TCE presented better rejections. A qualitative analysis of variables using Principal Component Analysis was successfully implemented for reduction of physical-chemical compound properties that influence membrane rejection of PhACs and organic compounds. Properties such as dipole moment, molar volume, hydrophobicity/hydrophilicity, molecular length and equivalent width were found to be important descriptors for simulation of membrane rejection. For membranes used in the experiments, we may conclude that charge repulsion was an important mechanism of rejection for ionic compounds. After analysis with Multiple Linear Regression, we also may conclude that membrane rejection of neutral compounds was well predicted by molar volume, length, equivalent width, hydrophobicity/hydrophilicity and dipole moment. Molecular weight was a poor descriptor variable for rejection modelling. We were able to provide acceptable statistical significance for important results.

  2. Comparing reports of peer rejection: associations with rejection sensitivity, victimization, aggression, and friendship.

    Science.gov (United States)

    Zimmer-Gembeck, Melanie J; Nesdale, Drew; McGregor, Leanne; Mastro, Shawna; Goodwin, Belinda; Downey, Geraldine

    2013-12-01

    Perceiving that one is rejected is an important correlate of emotional maladjustment. Yet, self-perceptions can substantially differ from classmate-reports of who is rejected. In this study, discrepancies between self- and classmate-reports of rejection were identified in 359 Australian adolescents (age 10-12 years). As expected, adolescents who overestimated rejection reported more rejection sensitivity and felt more victimized by their peers, but were not seen by peers as more victimized. Adolescents who underestimated rejection identified themselves as high in overt aggression, and their peers identified them as high in overt and relational aggression and low in prosocial behavior. Yet, underestimators' feelings of friendship satisfaction did not seem to suffer and they reported low rejection sensitivity. Results suggest that interventions to promote adolescent health should explicitly recognize the different needs of those who do and do not seem to perceive their high rejection, as well as adolescents who overestimate their rejection. PMID:24215970

  3. Renal allograft rejection: sonography and scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Singh, A.; Cohen, W.N.

    1980-07-01

    A total of 30 renal allograft patients who had sonographic B scanning and radionuclide studies of the transplant was studied as to whether: (1) the allograft rejection was associated with any consistent and reliable sonographic features and (2) the sonograms complemented the radionuclide studies. Focal areas of decreased parenchymal echogenicity were the most striking and consistent sonographic finding in chymal echogenicity were the most striking and consistens sonographic finding in allograft rejection. This was observed in most of the patients exhibiting moderate or severe rejection, but was frequently absent with mild rejection. Areas of decreased parenchymal echogenicity were not seen during episodes of acute tubular necrosis. Therefore, sonography showing zones of decreased parenchymal echogenicity was complementary to radionuclide studies in the diagnosis of allograft rejection versus acute tubular necrosis. Corticomedullary demarcation was difficult to interpret because of technical variables, and was inconsistently related to rejection in this series.

  4. Effect of nifedipine on renal transplant rejection.

    Science.gov (United States)

    Nicholson, M L; Dennis, M J; Beckingham, I J; Smith, S J

    1993-10-01

    The effect of early nifedipine therapy on acute renal allograft rejection was studied in 170 adult cadaveric transplant recipients. Acute rejection occurring in the first 3 months after transplantation was diagnosed by Tru-cut biopsy and the severity of each rejection episode assessed histologically. The incidence of acute rejection was significantly lower in patients treated with nifedipine (29 of 80; 36 per cent) than in controls (52 of 90; 58 per cent) (P nifedipine exerted a significant independent effect on the incidence of early acute rejection. Other factors identified in the multivariate model as influencing rejection were human leucocyte antigen (HLA) matching at the DR locus, blood level of cyclosporin during the first week, HLA matching at the B locus, donor age and donor sex. The 1-year graft survival rate was 88.6 per cent in patients given nifedipine and 63.8 per cent in controls (P nifedipine therapy has a useful role in human renal transplantation.

  5. Reverse osmosis membrane of high urea rejection properties. [water purification

    Science.gov (United States)

    Johnson, C. C.; Wydeven, T. J. (Inventor)

    1980-01-01

    Polymeric membranes suitable for use in reverse osmosis water purification because of their high urea and salt rejection properties are prepared by generating a plasma of an unsaturated hydrocarbon monomer and nitrogen gas from an electrical source. A polymeric membrane is formed by depositing a polymer of the unsaturated monomer from the plasma onto a substrate, so that nitrogen from the nitrogen gas is incorporated within the polymer in a chemically combined form.

  6. Saltstone Oxidation Study: Leaching Method

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C. A.; Stefanko, D. B.; Burns, H. H.

    2013-02-24

    Cementitious waste forms can be designed to chemically stabilize selected contaminants, such as Tc{sup +7} and Cr{sup +6}, by chemically reduction to lower valance states, Tc{sup +4} and Cr{sup +3}, respectively, and precipitation of these species in alkaline media as low solubility solid phases. Data for oxidation of this type of cementitious waste form cured under field conditions as a function of time is required for predicting the performance of the waste form and disposal facility. The rate of oxidation (oxidation front advancement) is an important parameter for predicting performance because the solubilities of some radionuclide contaminants, e.g., technetium, are a function of the oxidation state. A non-radioactive experiment was designed for quantifying the oxidation front advancement using chromium, as an approximate redox-sensitive surrogate (Cr{sup +6} / Cr{sup +3}) for technetium (Tc{sup +7} / Tc{sup +4}). Nonradioactive cementitious waste forms were prepared in the laboratory and cured under both laboratory and ?field conditions.? Laboratory conditions were ambient temperature and sealed sample containers. Field conditions were approximated by curing samples in open containers which were placed inside a plastic container stored outdoors at SRS. The container had a lid and was instrumented with temperature and humidity probes. Subsamples as thin as 0.2 mm were taken as a function of distance from the exposed surface of the as-cast sample. The subsamples were leached and the leachates were analyzed for chromium, nitrate, nitrite and sodium. Nitrate, nitrite, and sodium concentrations were used to provide baseline data because these species are not chemically retained in the waste form matrix to any significant extent and are not redox sensitive. ?Effective? oxidation fronts for Cr were measured for samples containing 1000, 500 and 20 mg/kg Cr added as soluble sodium chromate, Na{sub 2}CrO{sub 4}. For a sample cured for 129 days under field conditions

  7. LATE RENAL GRAFT REJECTION: PATHOLOGY AND PROGNOSIS

    Directory of Open Access Journals (Sweden)

    E.S. Stolyarevich

    2014-01-01

    Full Text Available Rejection has always been one of the most important cause of late renal graft dysfunction. Aim of the study was to analyze the prevalence of different clinico-pathological variants of rejection that cause late graft dysfunction, and evaluate their impact on long-term outcome. Materials and methods. This is a retrospective study that analyzed 294 needle core biopsy specimens from 265 renal transplant recipients with late (48,8 ± 46,1 months after transplantation allograft dysfunction caused by late acute rejection (LAR, n = 193 or chronic rejection (CR, n = 78 or both (n = 23. C4d staining was performed by immunofl uorescence (IF on frozen sections using a standard protocol. Results. Peritubular capillary C4d deposition was identifi ed in 36% samples with acute rejection and in 62% cases of chronic rejection (including 67% cases of transplant glomerulopathy, and 50% – of isolated chronic vasculopathy. 5-year graft survival for LAR vs CR vs their combination was 47, 13 and 25%, respectively. The outcome of C4d– LAR was (p < 0,01 better than of C4d+ acute rejection: at 60 months graft survival for diffuse C4d+ vs C4d− was 33% vs 53%, respectively. In cases of chronic rejection C4d+ vs C4d– it was not statistically signifi cant (34% vs 36%. Conclusion. In long-term allograft biopsy C4d positivity is more haracteristic for chronic rejection than for acute rejection. Only diffuse C4d staining affects the outcome. C4d– positivity is associated with worse allograft survival in cases of late acute rejection, but not in cases of chronic rejection

  8. Split Rejection in Vascularized Composite Allotransplantation

    OpenAIRE

    Sinha, Indranil; Pomahac, Bohdan

    2013-01-01

    Introduction: Graft monitoring following vascularized composite allotransplantation (VCA) relies primarily on serial skin biopsy. However, given that VCA comprised multiple tissue types, skin biopsy may not accurately reflect rejection in other transplanted tissue. Methods: A review of the literature on episodes of both acute and chronic rejection following VCA was completed. Special attention was given to how these patients were monitored for rejection and whether skin biopsy accurately refl...

  9. Leaching of complex sulphide concentrate in acidic cupric chloride solutions

    Institute of Scientific and Technical Information of China (English)

    M. TCHOUMOU; M. ROYNETTE

    2007-01-01

    The chemical analysis of a complex sulphide concentrate by emission spectrometry and X-ray diffraction shows that it contains essentially copper, lead, zinc and iron in the form of chalcopyrite, sphalerite and galena. A small amount of pyrite is also present in the ore but does not be detected with X-ray diffraction. The cupric chloride leaching of the sulphide concentrate at various durations and solid/liquid ratios at 100 ℃ shows that the rate of dissolution of the ore is the fastest in the first several hours, and after 12 h it does not evolve significantly. If oxygen is excluded from the aqueous cupric chloride solution during the leaching experiment at 100 ℃, the pyrite in the ore will not be leached. The determination of principal dissolved metals in the leaching liquor by flame atomic absorption spectrometry, and the chemical analysis of solid residues by emission spectrometry and X-ray diffraction allow to conclude that the rate of dissolution of the minerals contained in the complex sulphide concentrate are in the order of galena>sphalerite>chalcopyrite.

  10. The treatments of soil Rirang by floatation and Acid leaching

    International Nuclear Information System (INIS)

    The treatments of soil Rirang by floatation and acid leaching has been carried out to increase high uranium concentrates of materials, separating associated economical minerals and to reduce the gangue minerals which bothering at chemical processing. The physical treatment has been done by ore preparation and floatation using oleic acid and pine oil, 20 % of pulp at pH 9, condition time at 5 minutes and collections of float fraction was 10 minutes. The chemical processing has been done by dynamic leaching using H2SO4 100 kg/ton, MnO2 20 kg/ton, 50 % of solid with ore size - 65 mesh, temperature at 80 oC and time of leaching was 8 hours. The result of experiments is as follows : Physical treatment by floatation shown that the concentrates of U increased at sink fraction by (1.5 - 2) times against feed sample for all the samples, and in the float fraction the recovery of molybdenite separation is 58 - 81 % and rare earths is 57 - 80 %. The result of dynamic leaching is 76 - 91 %, and recovery uranium increasing from 81.02 % (mixture samples soil before floatation) to 91.16 % ( mixture samples of float fraction)

  11. Effect of processing history of pyrite on its leaching kinetics

    Institute of Scientific and Technical Information of China (English)

    赵中伟; 李洪桂; 孙培梅; 李运姣; 霍广生

    2003-01-01

    Different researchers often attained scattered kinetic results for the same leaching process. Usually, the difference is ascribed to the variation in mineral resource, chemical composition and, accuracy of experimental methods, while less attention is paid to the sample processing history. The present study shows that processing history of pyrite sample can cause great changes in its physico-chemical properties. Crushing, grinding and milling lead to an increase of the leachability of pyrite and the leaching becomes less temperature dependence owing to the decreasing of apparent activation energy of the reaction. The activation energy for its leaching in H2SO4-HNO3 solution is depressed from 73.9 to 47.5kJ/mol after being activated through vibrating milling for 40min. On the contrary, aging causes the reverse change owing to the release of extra inner energy stored during mechanical treatments. Thus activity of pyrite will decrease towards its original value. Surely the processing history of concentrate sample should be taken into consideration when studying the kinetics of leaching reaction.

  12. Determination of molybdenite leaching degree by x-ray radiometric analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bibinov, S.A.; Gladyshev, V.P.; Yarmolik, A.S.; Kim, A.Ch.; Sokur, N.P. (Vsesoyuznyj Nauchno-Issledovatel' skij, i Proektnyj Inst. Tugoplavikh Metallov i Tverdykh Splavov, Moscow (USSR))

    1984-01-01

    A express chemical X-ray radiometric method for determination of leaching degree and analysis of molybdenite products is developed. The method comprises chemical preparation and the following X-ray radiometric determination of molybdenum. Total duration of the analysis is 1-1.5 h. The best reproductivity is obtained at X-ray radiometric analysis as compared with the chemical one.

  13. Determination of molybdenite leaching degree by x-ray radiometric analysis

    International Nuclear Information System (INIS)

    A express chemical X-ray radiometric method for determination of leaching degree and analysis of molybdenite products is developed. The method comprises chemical preparation and the following X-ray radiometric determination of molyb bdenum. Total duration of the analysis is 1-1.5 h. The best reproductivity is btained at X-ray radiometric analysis as compared with the chemical one

  14. Are You Being Rejected or Excluded? Insights from Neuroimaging Studies Using Different Rejection Paradigms

    OpenAIRE

    Premkumar, Preethi

    2012-01-01

    Rejection sensitivity is the heightened tendency to perceive or anxiously expect disengagement from others during social interaction. There has been a recent wave of neuroimaging studies of rejection. The aim of the current review was to determine key brain regions involved in social rejection by selectively reviewing neuroimaging studies that employed one of three paradigms of social rejection, namely social exclusion during a ball-tossing game, evaluating feedback about preference from peer...

  15. Bioactive contaminants leach from disposable laboratory plasticware.

    Science.gov (United States)

    McDonald, G Reid; Hudson, Alan L; Dunn, Susan M J; You, Haitao; Baker, Glen B; Whittal, Randy M; Martin, Jonathan W; Jha, Amitabh; Edmondson, Dale E; Holt, Andrew

    2008-11-01

    Disposable plasticware such as test tubes, pipette tips, and multiwell assay or culture plates are used routinely in most biological research laboratories. Manufacturing of plastics requires the inclusion of numerous chemicals to enhance stability, durability, and performance. Some lubricating (slip) agents, exemplified by oleamide, also occur endogenously in humans and are biologically active, and cationic biocides are included to prevent bacterial colonization of the plastic surface. We demonstrate that these manufacturing agents leach from laboratory plasticware into a standard aqueous buffer, dimethyl sulfoxide, and methanol and can have profound effects on proteins and thus on results from bioassays of protein function. These findings have far-reaching implications for the use of disposable plasticware in biological research. PMID:18988846

  16. Not all rejections are alike; competence and warmth as a fundamental distinction in social rejection

    NARCIS (Netherlands)

    Celik, P.; Lammers, J.; Beest, I. van; Bekker, M.H.J.; Vonk, R.

    2013-01-01

    Social rejection can lead to a variety of emotions. Two studies show that specific emotional reactions to social rejection can be understood by relying on the fundamental distinction between competence and warmth. Rejection that is perceived to be due to incompetence leads to anger, whereas rejectio

  17. An adaptive algorithm for noise rejection.

    Science.gov (United States)

    Lovelace, D E; Knoebel, S B

    1978-01-01

    An adaptive algorithm for the rejection of noise artifact in 24-hour ambulatory electrocardiographic recordings is described. The algorithm is based on increased amplitude distortion or increased frequency of fluctuations associated with an episode of noise artifact. The results of application of the noise rejection algorithm on a high noise population of test tapes are discussed.

  18. 21 CFR 1230.47 - Rejected containers.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rejected containers. 1230.47 Section 1230.47 Food... FEDERAL CAUSTIC POISON ACT Imports § 1230.47 Rejected containers. (a) In all cases where the containers... notification to the importer that the containers must be exported under customs supervision within 3...

  19. Renal allograft rejection. Unusual scintigraphic findings

    Energy Technology Data Exchange (ETDEWEB)

    Desai, A.G.; Park, C.H.

    1986-11-01

    During sequential renal imagining for evaluation of clinically suspected rejection, focal areas of functioning renal tissue were seen in two cases of renal transplant in the midst of severe and irreversible renal allograft rejection. A probable explanation for this histopathologically confirmed and previously unreported finding is discussed.

  20. Investigation of Leaching Kinetics of Copper from Malachite Ore in Ammonium Nitrate Solutions

    Science.gov (United States)

    Ekmekyapar, Ahmet; Aktaş, Evrim; Künkül, Asim; Demirkiran, Nizamettin

    2012-08-01

    The production of metallic copper from low-grade copper ores is generally carried out by hydrometallurgical methods. Leaching is the first prerequisite of any hydrometallurgical process. Solutions containing ammonia may allow for selective leaching of the copper from the ore. In this study, the leaching kinetics of malachite, which is an oxidized copper ore, in ammonium nitrate solutions was examined. The effects of some experimental parameters on the leaching process were investigated, and a kinetic model to represent the effects of these parameters on the leaching rate was developed. It was determined that the leaching rate increased with increasing solution concentration, temperature, and agitation speed, as well as decreasing particle size. It was found that the leaching reaction followed the mixed kinetic controlled model, which includes two different leaching processes including the surface chemical reaction (303 K to 323 K [30 °C to 50 °C]) and diffusion through a porous product layer (323 K to 343 K [50 °C to 70 °C]). The activation energies of these sequential steps were determined to be 95.10 and 29.50 kJ/mol, respectively.

  1. Image rejects/retakes-radiographic challenges

    International Nuclear Information System (INIS)

    A general held position among radiological personnel prior to digitalisation was that the problem of image rejects/retakes should more or less vanish. However, rejects/retakes still impose several challenges within radiographic imaging; they occupy unnecessary resources, expose patients to unnecessary ionizing radiation and may also indicate suboptimal quality management. The latter is the main objective of this paper, which is based on a survey of international papers published both for screen/film and digital technology. The digital revolution in imaging seems to have reduced the percentage of image rejects/retakes from 10-15 to 3-5%. The major contribution to the decrease appears to be the dramatic reduction of incorrect exposures. At the same time, rejects/retakes due to lack of operator competence (positioning, etc.) are almost unchanged, or perhaps slightly increased (due to lack of proper technical competence, incorrect organ coding, etc.). However, the causes of rejects/retakes are in many cases defined and reported with reference to radiographers' subjective evaluations. Thus, unless radiographers share common views on image quality and acceptance criteria, objective measurements and assessments of reject/retake rates are challenging tasks. Interestingly, none of the investigated papers employs image quality parameters such as 'too much noise' as categories for rejects/retakes. Surprisingly, no reject/retake analysis seems yet to have been conducted for direct digital radiography departments. An increased percentage of rejects/retakes is related to 'digital skills' of radiographers and therefore points to areas for extended education and training. Furthermore, there is a need to investigate the inter subjectivity of radiographers' perception of, and attitude towards, both technical and clinical image quality criteria. Finally, there may be a need to validate whether reject/retake rate analysis is such an effective quality indicator as has been asserted

  2. Image rejects/retakes--radiographic challenges.

    Science.gov (United States)

    Waaler, D; Hofmann, B

    2010-01-01

    A general held position among radiological personnel prior to digitalisation was that the problem of image rejects/retakes should more or less vanish. However, rejects/retakes still impose several challenges within radiographic imaging; they occupy unnecessary resources, expose patients to unnecessary ionizing radiation and may also indicate suboptimal quality management. The latter is the main objective of this paper, which is based on a survey of international papers published both for screen/film and digital technology. The digital revolution in imaging seems to have reduced the percentage of image rejects/retakes from 10-15 to 3-5 %. The major contribution to the decrease appears to be the dramatic reduction of incorrect exposures. At the same time, rejects/retakes due to lack of operator competence (positioning, etc.) are almost unchanged, or perhaps slightly increased (due to lack of proper technical competence, incorrect organ coding, etc.). However, the causes of rejects/retakes are in many cases defined and reported with reference to radiographers' subjective evaluations. Thus, unless radiographers share common views on image quality and acceptance criteria, objective measurements and assessments of reject/retake rates are challenging tasks. Interestingly, none of the investigated papers employs image quality parameters such as 'too much noise' as categories for rejects/retakes. Surprisingly, no reject/retake analysis seems yet to have been conducted for direct digital radiography departments. An increased percentage of rejects/retakes is related to 'digital skills' of radiographers and therefore points to areas for extended education and training. Furthermore, there is a need to investigate the inter-subjectivity of radiographers' perception of, and attitude towards, both technical and clinical image quality criteria. Finally, there may be a need to validate whether reject/retake rate analysis is such an effective quality indicator as has been asserted

  3. Uranium leaching by fungal metabolite

    International Nuclear Information System (INIS)

    To explore new means of bioleaching, one strain of high-yielding fungi-Aspergillus niger which could produce organic acids was separated and purified from soil samples of uranium mine. The influence of cultural temperature, initial pH value, inoculum sizes on its growth characteristics were carried out. And the tests of uranium leaching of metabolin of Aspergillus niger were operated. On these tests, the effects of metabolin of Aspergillus niger with different pH value produced in the diverse culture temperature on uranium leaching were investigated. The results show that this strain of Aspergillus niger can grow best under the following conditions: the temperature is 37℃, the initial pH value is 7.0, the inoculum sizes is 2% (the OD value of the spores solution is 0.06). The uranium extraction effects relative to the final pH value of the cultures. and the maximum leaching rates is 83.05% when the pH value is 2.3. (authors)

  4. Major leaching processes of combustion residues - Characterisation, modelling and experimental investigation

    Energy Technology Data Exchange (ETDEWEB)

    Yan Jinying

    1998-12-31

    Characterising leaching behaviour provides ample evidence to identify the major leaching processes of combustion residues. Neutralisation and chemical weathering govern the leaching reactions and control the release of elements from combustion residues, and are thus considered to be the major leaching processes. According to experimental investigations and geochemical simulations, the leaching kinetics of buffering materials are key issues for the understanding of the neutralizing processes. The acid neutralizing capacity at different pH levels depends mainly on the mineralogy of the combustion residues. In combustion residues, the dissolution of glass phases is expected to play an important role in a long-term neutralizing process. The neutralizing process in a flow system is significantly different from that in a batch system. The neutralizing ability of a combustion residue may be strongly affected by solute transport and carbonation reactions in a natural leaching environment. The chemical weathering mainly involves the matrix of combustion residues consisting mostly of glass phases. The dissolution kinetics of waste glass and other possible processes involved in the chemical weathering have been investigated and incorporated into a kinetic reactive transport model. Most important processes in the chemical weathering can be simulated simultaneously using this model. The results show that there is a complicated relationship between the factors controlling the long-term chemical weathering. The environmental impact of the glass dissolution cannot be neglected. Although the glass dissolution provides considerable buffering capacity in long-term weathering, the carbonate is usually a dominant buffering mineral in actual weathering processes. The transformation of carbonate should be considered as an important process in the chemical weathering. The formation of secondary minerals may considerably alter the mineralogy of the waste, and thus change the leaching

  5. Desorption, persistence, and leaching of dibenzofuran in European Soils

    OpenAIRE

    Celis, R.; Real Ojeda, Miguel; Hermosín, M. C.; Cornejo, J.

    2006-01-01

    Polycyclic aromatic hydrocarbons (PAHs) and their heterocyclic analogs (hetero-PAHs) represent the predominant chemical classes in many contaminated soils. Despite the fact that hetero-PAHs are more soluble and hence potentially more mobile and bioavailable than similar nonsubstituted compounds, the existing information about the fate of these compounds in the soil environment is limited. In this article, laboratory experiments were designed to assess the desorption, persistence, and leaching...

  6. Leaching of atrazine and deethylatrazine under a vegetative filter strip

    OpenAIRE

    DELPHIN, Jean-Emmanuel; Chapot, Jean-Yves

    2001-01-01

    International audience Vegetative filter strips (VFS) are a device used successfully to control erosion and to reduce the amount of chemical pollutants in surface waters. Part of the surface water runoff is removed by the VFS by infiltration. The objective of this study, conducted for three years under natural conditions, was to investigate the fate and evaluate the leaching of atrazine and deethylatrazine (DEA) transported in runoff effluents and trapped by a VFS. Soil solution was sample...

  7. Weatherability and Leach Resistance of Wood Impregnated with Nano-Zinc Oxide

    OpenAIRE

    Nami Kartal S; Clausen Carol; Green Frederick

    2010-01-01

    Abstract Southern pine specimens vacuum-treated with nano-zinc oxide (nano-ZnO) dispersions were evaluated for leach resistance and UV protection. Virtually, no leaching occurred in any of the nano-ZnO–treated specimens in a laboratory leach test, even at the highest retention of 13 kg/m3. However, specimens treated with high concentrations of nano-ZnO showed 58–65% chemical depletion after 12 months of outdoor exposure. Protection from UV damage after 12 months exposure is visibl...

  8. Leaching characteristics of Wadi Belih uraniferous Hammamat sediments,eastern desert,Egypt

    International Nuclear Information System (INIS)

    This work deals with the direct chemical treatment of Wadi Belih uraniferous ore material using the agitation leaching technique. The study ore is mainly localized in siltstones belonging to the Hammamat sediments situated in the northern part of the eastern desert. The uranium mineral in the ore are mainly represented by the silicate mineral uranophane, the vanadate mineral tyuyamunite and to a laser extent the sulphate mineral shroekingerite, both acid (sulphuric acid) alkaline (sodium carbonate and bicarbonate) leaching methods have been applied beside sodium and ferric chlorides. The latter leaching reagents are greatly beneficial in removing radium together with uranium, a matter which is greatly important for environmental concerns

  9. Leaching effect on arsenic mobility in agricultural soils.

    Science.gov (United States)

    Dousova, Barbora; Buzek, Frantisek; Lhotka, Miloslav; Krejcova, Stanislava; Boubinova, Radka

    2016-04-15

    The stability of soil arsenic during long-term leaching was studied in four soils from an agricultural area. Two identical columns simulating soil profiles of three layers were leached with As-free natural rainwater (flow (μgg(-1)day(-1)) showed a comparable run for all soils, with the peak corresponding to maximum As release in the first leaching stage, and then with a tendency to equilibrate. The amount of released As was controlled by the saturated hydraulic conductivity Ksat and free Fe oxides, and the kinetics of the leaching process correlated with the content of organic matter (OM). An overall stability and accumulation of soil arsenic were mostly affected by soil properties (Ksat, particle size, clay fraction), while the chemical composition (Fe, OM content) and surface properties (specific surface area SBET, theoretical adsorption capacity Qt) were of marginal significance. The distribution of As forms was performed by sequential extraction (SEP), which indicated negligible transformation (<12%) of As species in upper soil layers. PMID:26785213

  10. Rejection of pharmaceuticals by forward osmosis membranes.

    Science.gov (United States)

    Jin, Xue; Shan, Junhong; Wang, Can; Wei, Jing; Tang, Chuyang Y

    2012-08-15

    Rejection of four pharmaceutical compounds, carbamazepine, diclofenac, ibuprofen and naproxen, by forward osmosis (FO) membranes was investigated in this study. For the first time, the rejection efficiency of the pharmaceutical compounds was compared between commercial cellulose triacetate (CTA) based membranes and thin film composite (TFC) polyamide based membranes. The rejection behavior was related to membrane interfacial properties, physicochemical characteristics of the pharmaceutical molecules and feed solution pH. TFC polyamide membranes exhibited excellent overall performance, with high water flux, excellent pH stability and great rejection of all pharmaceuticals investigated (>94%). For commercial CTA based FO membranes, hydrophobic interaction between the compounds and membranes exhibited strong influence on their rejection under acidic conditions. The pharmaceuticals rejection was well correlated to their hydrophobicity (log D). Under alkaline conditions, both electrostatic repulsion and size exclusion contributed to the removal of deprotonated molecules. The pharmaceuticals rejection by CTA-HW membrane at pH 8 followed the order: diclofenac (99%)>carbamazepine (95%)>ibuprofen (93%) ≈ naproxen (93%). These results can be important for FO membrane synthesis, modification and their application in water purification. PMID:22640821

  11. Characterization and Leach Testing for REDOX Sludge and S-Saltcake Actual Waste Sample Composites

    Energy Technology Data Exchange (ETDEWEB)

    Fiskum, Sandra K.; Buck, Edgar C.; Daniel, Richard C.; Draper, Kathryn E.; Edwards, Matthew K.; Hubler, Timothy L.; Jagoda, Lynette K.; Jenson, Evan D.; Kozelisky, Anne E.; Lumetta, Gregg J.; MacFarlan, Paul J.; McNamara, Bruce K.; Peterson, Reid A.; Sinkov, Sergey I.; Snow, Lanee A.; Swoboda, Robert G.

    2008-07-10

    This report describes processing and analysis results of boehmite waste type (Group 5) and insoluble high Cr waste type (Group 6). The sample selection, compositing, subdivision, physical and chemical characterization are described. Extensive batch leach testing was conducted to define kinetics and leach factors of selected analytes as functions of NaOH concentration and temperature. Testing supports issue M-12 resolution for the Waste Treatment Plant.

  12. Best Management Practices for Minimizing Nitrate Leaching from Container-Grown Nurseries

    OpenAIRE

    Jianjun Chen; Yingfeng Huang; Russell D. Caldwell

    2001-01-01

    Containerized plant production represents an extremely intensive agricultural practice; 40,000 to 300,000 containers may occupy one acre of surface area to which a large amount of chemical fertilizer is applied. Currently, recommended fertilizer application rates for the production of containerized nursery ornamental plants are in excess of plant requirements, and up to 50% of the applied fertilizers may run off or be leached from containers. Among the nutrients leached or allowed to runoff, ...

  13. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  14. Modelling inorganic and organic biocide leaching from CBA-amine (Copper–Boron–Azole) treated wood based on characterisation leaching tests

    Energy Technology Data Exchange (ETDEWEB)

    Lupsea, Maria [University of Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F–31077 Toulouse (France); INRA, UMR 792, F-31400 Toulouse (France); CNRS, UMR 5504, F-31400 Toulouse (France); Paris-Est University, CSTB — Scientific and Technical Centre for the Building Industry, DEE/Environment and Life Cycle Engineering Team, 24 Rue Joseph Fourier, F-38400 Saint Martin d' Hères (France); Tiruta-Barna, Ligia, E-mail: ligia.barna@insa-toulouse.fr [University of Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F–31077 Toulouse (France); INRA, UMR 792, F-31400 Toulouse (France); CNRS, UMR 5504, F-31400 Toulouse (France); Schiopu, Nicoleta [Paris-Est University, CSTB — Scientific and Technical Centre for the Building Industry, DEE/Environment and Life Cycle Engineering Team, 24 Rue Joseph Fourier, F-38400 Saint Martin d' Hères (France); Schoknecht, Ute [BAM — Federal Institute for Materials Research and Testing, Division 4.1, Unter den Eichen 87, 12205 Berlin (Germany)

    2013-09-01

    Numerical simulation of the leaching behaviour of treated wood is the most pertinent and less expensive method for the prediction of biocides' release in water. Few studies based on mechanistic leaching models have been carried out so far. In this work, a coupled chemistry-mass transport model is developed for simulating the leaching behaviour of inorganic (Cu, B) and organic (Tebuconazole) biocides from CBA-amine treated wood. The model is based on experimental investigations (lab-scale leaching tests coupled with chemical and structural analysis). It considers biocides' interactions with wood solid components and with extractives (literature confirmed reactions), as well as transport mechanisms (diffusion, convection) in different compartments. Simulation results helped at identifying the main fixation mechanisms, like (i) direct complexation of Cu by wood-phenolic and -carboxylic sites (and not via monoethanolamine; complex) on lignin and hemicellulose and strong dependence on extractives' nature, (ii) pH dependent binding of tebuconazole on polarized -OH moieties on wood. The role of monoethanolamine is to provide a pore-solution pH of about 7.5, when copper solubility is found to be weakest. The capability of the developed model to simulate the chemical and transport behaviour is the main result of this study. Moreover, it proved that characterization leaching tests (pH dependency and dynamic tests), combined with appropriate analytical methods are useful experimental tools. Due to its flexibility for representing and simulating various leaching conditions, chemical-transport model developed could be used to further simulate the leaching behaviour of CBA treated wood at larger scales. - Highlights: • Biocide and extractives leaching from ammonia-CBA treated wood were modelled. • The chemical-transport model identifies the main fixation/solubilisation mechanisms. • The model describes well the results of equilibrium and dynamic leaching

  15. Pericytes, microvasular dysfunction, and chronic rejection.

    Science.gov (United States)

    Kloc, Malgorzata; Kubiak, Jacek Z; Li, Xian C; Ghobrial, Rafik M

    2015-04-01

    Chronic rejection of transplanted organs remains the main obstacle in the long-term success of organ transplantation. Thus, there is a persistent quest for development of antichronic rejection therapies and identification of novel molecular and cellular targets. One of the potential targets is the pericytes, the mural cells of microvessels, which regulate microvascular permeability, development, and maturation by controlling endothelial cell functions and regulating tissue fibrosis and inflammatory response. In this review, we discuss the potential of targeting pericytes in the development of microvasular dysfunction and the molecular pathways involved in regulation of pericyte activities for antichronic rejection intervention.

  16. Leaching kinetics of ionic rare-earth in ammonia-nitrogen wastewater system added with impurity inhibitors

    Institute of Scientific and Technical Information of China (English)

    邱廷省; 朱冬梅; 方夕辉; 曾清华; 高广阔; 朱华磊

    2014-01-01

    Ammonia-nitrogen wastewater is produced during the dressing and smelting process of rare-earth ores. Such wastewater includes a very high concentration of NH4+, as well as other ions (e.g., NH4+, RE3+, Al3+, Fe3+, Ca2+, Cl–, and SiO32–) with a pH of 5.4–5.6. Its direct discharge will pollute, yet it can be recycled and used as a leaching reagent for ionic rare-earth ores. In this study, leaching kinetics studies of both rare earth ions and impurity ion Al3+were conducted in the ammonia-nitrogen wastewater system with the aid of impurity inhibitors. Results showed that the leaching process of rare-earth followed the internal diffusion kinetic model. When the temperature was 298 K and the concentration of NH4+was 0.3 mol/L, the leaching reaction rate constant of ionic rare-earth was 1.72 and the apparent activation energy was 9.619 kJ/mol. The leaching rate was higher than that of conventional leaching system with ammonium sulfate, which indicated that ammonia-nitrogen wastewater system and the addition of impurity inhibitors could pro-mote ionic rare-earth leaching. The leaching kinetic process of impurity Al3+did not follow either internal diffusion kinetic model or chemical reaction control, but the hybrid control model which was affected by a number of process factors. Thus, during the industrial production the leaching of impurity ions could be reduced by increasing the concentration of impurity inhibitors, reducing the leach-ing temperature to a proper range, accelerating the seepage velocity of leaching solution, or increasing the leaching rate of rare earths.

  17. Assessing the impact of regional rainfall variability on rapid pesticide leaching potential.

    Science.gov (United States)

    McGrath, Gavan; Hinz, Christoph; Sivapalan, Murugesu

    2010-04-01

    The timing and magnitude of rainfall events are known to be dominant controls on pesticide migration into streams and groundwater, by triggering rapid flow processes, such as preferential flow and surface runoff. A better understanding of how regional differences in rainfall impact rapid leaching risk is required in order to match the scale at which water regulation occurs. We estimated the potential amount of rapid leaching, and the frequencies of these events in a case study of the southwest of Western Australia, for one soil type and a range of linearly sorbing, first order degrading chemicals. At the regional scale, those chemicals with moderate sorption and long half lives were the most susceptible to rapid transport within a year of application. Within the region, this susceptibility varied depending upon application time and seasonality in storm patterns. Those chemicals and areas with a high potential for rapid transport on average, also experience the greatest inter-annual variability in rapid leaching, as measured by the coefficient of variation. The timing and frequencies of rapid leaching events appeared to strongly relate to an area's relative susceptibility to rapid leaching. In the study region the results also suggested that frontal rainfall dominates rapid leaching along the western and southern coasts while convective thunderstorms play a greater role in the arid east. PMID:20079952

  18. Modelling and simulation of concrete leaching under outdoor exposure conditions.

    Science.gov (United States)

    Schiopu, Nicoleta; Tiruta-Barna, Ligia; Jayr, Emmanuel; Méhu, Jacques; Moszkowicz, Pierre

    2009-02-15

    Recently, a demand regarding the assessment of release of dangerous substances from construction products was raised by European Commission which has issued the Mandate M/366 addressed to CEN. This action is in relation with the Essential Requirement No. 3 "Hygiene, Health and Environment" of the Construction Products Directive (89/106/EC). The potential hazard for environment and health may arise in different life cycle stages of a construction product. During the service life stage, the release of substances due to contact with the rain water is the main potential hazard source, as a consequence of the leaching phenomenon. The objective of this paper is to present the development of a coupled chemical-transport model for the case of a concrete based construction product, i.e. concrete paving slabs, exposed to rain water under outdoor exposure conditions. The development of the model is based on an iterative process of comparing the experimental results with the simulated results up to an acceptable fit. The experiments were conducted at laboratory scale (equilibrium and dynamic leaching tests) and field scale. The product was exposed for one year in two types of leaching scenarios under outdoor conditions, "runoff" and "stagnation", and the element release was monitored. The model was calibrated using the experimental data obtained at laboratory scale and validated against measured field data, by taking into account the specific rain water balance and the atmospheric CO2 uptake as input parameters. The numerical tool used in order to model and simulate the leaching behaviour was PHREEQC, coupled with the Lawrence Livermore National Laboratory (LLNL) thermodynamic data base. The simulation results are satisfying and the paper demonstrates the feasibility of the modelling approach for the leaching behaviour assessment of concrete type construction materials. PMID:19118868

  19. Method of continuous pressure leaching of ores

    International Nuclear Information System (INIS)

    Ore leaching, especially suspensions of ground ore or fine ore fractions from physical treatment was divided into two operations. The former, i.e., ore mixing with technical grade concentrated sulfuric acid proceeded in a separate mixer. The mixture was then transported into an autoclave where the actual leaching proceeded for 2 to 4 hours. The extracted mixture was discharged through the autoclave bottom. The leaching autoclave used can be without any inner structures. The separation of mixing from the actual leaching allows processing ores with high levels of clay components, increasing operating reliability of the facility, reducing consumption of special structural materials and energy, and increasing process efficiency. (E.S.)

  20. Structural Decoupling and Disturbance Rejection in a Distillation Column

    DEFF Research Database (Denmark)

    Bahar, Mehrdad; Jantzen, Jan; Commault, C.;

    1996-01-01

    Introduction, distillation column model, input-output decoupling, disturbance rejection, concluding remarks, references.......Introduction, distillation column model, input-output decoupling, disturbance rejection, concluding remarks, references....

  1. Leaching of wood ash - Laboratory and field studies; Lakning av vedaska - Laboratorie- och faeltstudier

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, Per-Erik

    2012-02-15

    High forest production leads to diminishing amounts of base cations and micro nutrients in forest soils. This is due to uptake in, and harvest of, the trees. Losses can be compensated for by spreading stabilized wood ash on the forest ground, which means recycling of base cations and micro nutrients. Chemical composition of wood ash can easily be described by standard methods in the laboratory. However, this does not include the process of leaching in nature, such as which components and leaching rate for different compounds. During field conditions several factors are added, which are not available in the laboratory. After almost 10 years in the forest soils there still remains large quantities of the original product. Only 10-30 % of the wood ash products and 5 % of the lime product has been leached. In the laboratory study the leached amount was slightly larger, at the most 35 % for wood ash and 20 % for lime. Both studies indicate long time for weathering of the products in forest soils. Slower leaching rate from pellets of wood ash compared to leaching rate from crushed wood ash in the laboratory study is not verified by the field study. This indicates limited possibilities to control rates of leaching in the environment

  2. Intensification of pretreatment and pressure leaching of copper anode slime by microwave radiation

    Institute of Scientific and Technical Information of China (English)

    杨洪英; 马致远; 黄松涛; 吕阳; 熊柳

    2015-01-01

    The application of microwave irradiation for pretreatment of copper anode slime with high nickel content prior to pressure sulfuric acid leaching has been proposed. The microwave-assisted pretreatment is a rapid and efficient process. Through the technology of microwave assisted pretreatment-pressure leaching of copper anode slime, copper, tellurium, selenium and nickel are almost completely recovered. Under optimal conditions, the leaching efficiencies of copper, tellurium, selenium and nickel are 97.12%, 95.97%, 95.37% and 93.90%, respectively. The effect of microwave radiation on the temperature of copper anode slime and leaching solution is investigated. It is suggested that the enhancement on the recoveries of copper, tellurium and selenium can be attributed to the temperature gradient which is caused by shallow microwave penetration depth and super heating occurring at the solid–liquid interface. The kinetic study shows that the pressure leaching of copper anode slime, with and without microwave assisted pretreatment, are both controlled by chemical reactions on the surfaces of particles. It is found that the activation energy calculated for microwave-assisted pretreatment-pressure leaching (49.47 kJ/mol) is lower than that for pressure leaching which is without microwave assisted pretreatment (60.57 kJ/mol).

  3. Effect of ferrous metal presence on lead leaching in municipal waste incineration bottom ashes.

    Science.gov (United States)

    Oehmig, Wesley N; Roessler, Justin G; Zhang, Jianye; Townsend, Timothy G

    2015-01-01

    The recovery of ferrous and non-ferrous metals from waste to energy (WTE) ash continues to advance as the sale of removed metals improves the economics of waste combustion. Published literature suggests that Fe and Fe oxides play a role in suppressing Pb leaching in the Toxicity Characteristic Leaching Procedure (TCLP); further removal of ferrous metals from WTE ashes may facilitate higher Pb leaching under the TCLP. Eight WTE bottom ash size-fractions, from three facilities, were evaluated to assess the effect of metallic Fe addition and ferrous metal removal on TCLP leaching. Metallic Fe addition was demonstrated to reduce Pb leaching; the removal of ferrous metals by magnet resulted in a decrease in total available Pb (mg/kg) in most ash samples, yet Pb leachability increased in 5 of 6 ash samples. The research points to two chemical mechanisms to explain these results: redox interactions between Pb and Fe and the sorption of soluble Pb onto Fe oxide surfaces, as well as the effect of the leachate pH before and after metals recovery. The findings presented here indicate that generators, processors, and regulators of ash should be aware of the impact ferrous metal removal may have on Pb leaching, as a substantial increase in leaching may have significant implications regarding the management of WTE ashes. PMID:25464288

  4. Corneal Graft Rejection: Incidence and Risk Factors

    Directory of Open Access Journals (Sweden)

    Alireza Baradaran-Rafii

    2008-12-01

    Full Text Available

    PURPOSE: To determine the incidence and risk factors of late corneal graft rejection after penetrating keratoplasty (PKP. METHODS: Records of all patients who had undergone PKP from 2002 to 2004 without immunosuppressive therapy other than systemic steroids and with at least one year of follow up were reviewed. The role of possible risk factors such as demographic factors, other host factors, donor factors, indications for PKP as well as type of rejection were evaluated. RESULTS: During the study period, 295 PKPs were performed on 286 patients (176 male, 110 female. Mean age at the time of keratoplasty was 38±20 (range, 40 days to 90 years and mean follow up period was 20±10 (range 12-43 months. Graft rejection occurred in 94 eyes (31.8% at an average of 7.3±6 months (range, 20 days to 39 months after PKP. The most common type of rejection was endothelial (20.7%. Corneal vascularization, regrafting, anterior synechiae, irritating sutures, active inflammation, additional anterior segment procedures, history of trauma, uncontrolled glaucoma, prior graft rejection, recurrence of herpetic infection and eccentric grafting increased the rate of rejection. Patient age, donor size and bilateral transplantation had no significant influence on graft rejection. CONCLUSION: Significant risk factors for corneal graft rejection include

  5. Aluminium leaching from red mud by filamentous fungi.

    Science.gov (United States)

    Urík, Martin; Bujdoš, Marek; Milová-Žiaková, Barbora; Mikušová, Petra; Slovák, Marek; Matúš, Peter

    2015-11-01

    This contribution investigates the efficient and environmentally friendly aluminium leaching from red mud (bauxite residue) by 17 species of filamentous fungi. Bioleaching experiments were examined in batch cultures with the red mud in static, 7-day cultivation. The most efficient fungal strains in aluminium bioleaching were Penicillium crustosum G-140 and Aspergillus niger G-10. The A. niger G-10 strain was capable to extract up to approximately 141 mg·L(-1) of aluminium from 0.2 g dry weight red mud. Chemical leaching with organic acids mixture, prepared according to A. niger G-10 strain's respective fungal excretion during cultivation, proved that organic acids significantly contribute to aluminium solubilization from red mud.

  6. Aluminium leaching from red mud by filamentous fungi.

    Science.gov (United States)

    Urík, Martin; Bujdoš, Marek; Milová-Žiaková, Barbora; Mikušová, Petra; Slovák, Marek; Matúš, Peter

    2015-11-01

    This contribution investigates the efficient and environmentally friendly aluminium leaching from red mud (bauxite residue) by 17 species of filamentous fungi. Bioleaching experiments were examined in batch cultures with the red mud in static, 7-day cultivation. The most efficient fungal strains in aluminium bioleaching were Penicillium crustosum G-140 and Aspergillus niger G-10. The A. niger G-10 strain was capable to extract up to approximately 141 mg·L(-1) of aluminium from 0.2 g dry weight red mud. Chemical leaching with organic acids mixture, prepared according to A. niger G-10 strain's respective fungal excretion during cultivation, proved that organic acids significantly contribute to aluminium solubilization from red mud. PMID:26365318

  7. Crosslinked cellulose thin film composite nanofiltration membranes with zero salt rejection

    KAUST Repository

    Puspasari, Tiara

    2015-05-14

    We report a new synthetic route of fabricating regenerated cellulose nanofiltration membranes. The membranes are composite membranes with a thin selective layer of cellulose, which was prepared by regeneration of trimethylsilyl cellulose (a hydrophobic cellulose derivative) film followed by crosslinking. Filtration experiments using mixtures of sugar and sodium chloride showed that solutes above 300 Da were highly rejected whereas practically no rejection was observed for NaCl. This is a big advantage for a complete desalination as the existing commercial nanofiltration membranes typically exhibit NaCl rejection in the range of 30–60%. Membranes with zero NaCl rejection are required for recovery and purification applications in food, chemical and pharmaceutical industry.

  8. Image rejects in general direct digital radiography

    International Nuclear Information System (INIS)

    The number of rejected images is an indicator of image quality and unnecessary imaging at a radiology department. Image reject analysis was frequent in the film era, but comparably few and small studies have been published after converting to digital radiography. One reason may be a belief that rejects have been eliminated with digitalization. To measure the extension of deleted images in direct digital radiography (DR), in order to assess the rates of rejects and unnecessary imaging and to analyze reasons for deletions, in order to improve the radiological services. All exposed images at two direct digital laboratories at a hospital in Norway were reviewed in January 2014. Type of examination, number of exposed images, and number of deleted images were registered. Each deleted image was analyzed separately and the reason for deleting the image was recorded. Out of 5417 exposed images, 596 were deleted, giving a deletion rate of 11%. A total of 51.3% were deleted due to positioning errors and 31.0% due to error in centering. The examinations with the highest percentage of deleted images were the knee, hip, and ankle, 20.6%, 18.5%, and 13.8% respectively. The reject rate is at least as high as the deletion rate and is comparable with previous film-based imaging systems. The reasons for rejection are quite different in digital systems. This falsifies the hypothesis that digitalization would eliminates rejects. A deleted image does not contribute to diagnostics, and therefore is an unnecessary image. Hence, the high rates of deleted images have implications for management, training, education, as well as for quality

  9. COMPARE AND ANALYSES OF OPTIMIZED R-LEACH WITH LEACH ALGORITHM IN WSN

    Directory of Open Access Journals (Sweden)

    Tarun Sharma

    2015-11-01

    Full Text Available Wireless sensor networks are composed of numerous small charge, little power devices with sensing, local processing and wireless communication capabilities. Minimizing energy consumption and maximizing network lifespan are significant issues in the design of routing protocols for sensor networks. In this paper, we analyses the efficiency of LEACH protocol in extending the existence for energy-constrained wireless sensor networks. Based on LEACH protocol, an enhanced protocol termed as R- LEACH is proposed which aims to diminish energy consumption within the wireless sensor networks. The simulation results suggest R-LEACH protocol could equilibrium network energy consumption and extend the network lifecycle more successfully as compared to LEACH.

  10. Study on Leaching of Hexavalent Chromium from Hardened Concretes Using Tank Leaching Test

    OpenAIRE

    Takahashi, Shigeru; Sakai, Etsuo; Sugiyama, Takafumi

    2007-01-01

    Tank leaching tests were carried out to investigate the behavior of leaching trace elements from monolith samples. This study consists of two series, and the trace element used was hexavalent chromium. In Series I, the influence of the leachant/surface area of the specimen (L/S ratio) on the leaching amount was investigated. The leaching amount was found to increase with the amount of worked water. This shows that any L/S ratio can be selected in the tank leaching test. In Series II, th...

  11. Atrazine leaching from biochar-amended soils.

    Science.gov (United States)

    Delwiche, Kyle B; Lehmann, Johannes; Walter, M Todd

    2014-01-01

    The herbicide atrazine is used extensively throughout the United States, and is a widespread groundwater and surface water contaminant. Biochar has been shown to strongly sorb organic compounds and could be used to reduce atrazine leaching. We used lab and field experiments to determine biochar impacts on atrazine leaching under increasingly heterogeneous soil conditions. Application of pine chip biochar (commercially pyrolyzed between 300 and 550 °C) reduced cumulative atrazine leaching by 52% in homogenized (packed) soil columns (p=0.0298). Biochar additions in undisturbed soil columns did not significantly (p>0.05) reduce atrazine leaching. Mean peak groundwater atrazine concentrations were 53% lower in a field experiment after additions of 10 t ha(-1) acidified biochar (p=0.0056) relative to no biochar additions. Equivalent peat applications by dry mass had no effect on atrazine leaching. Plots receiving a peat-biochar mixture showed no reduction, suggesting that the peat organic matter may compete with atrazine for biochar sorption sites. Several individual measurement values outside the 99% confidence interval in perched groundwater concentrations indicate that macropore structure could contribute to rare, large leaching events that are not effectively reduced by biochar. We conclude that biochar application has the potential to decrease peak atrazine leaching, but heterogeneous soil conditions, especially preferential flow paths, may reduce this impact. Long-term atrazine leaching reductions are also uncertain.

  12. Atrazine leaching from biochar-amended soils.

    Science.gov (United States)

    Delwiche, Kyle B; Lehmann, Johannes; Walter, M Todd

    2014-01-01

    The herbicide atrazine is used extensively throughout the United States, and is a widespread groundwater and surface water contaminant. Biochar has been shown to strongly sorb organic compounds and could be used to reduce atrazine leaching. We used lab and field experiments to determine biochar impacts on atrazine leaching under increasingly heterogeneous soil conditions. Application of pine chip biochar (commercially pyrolyzed between 300 and 550 °C) reduced cumulative atrazine leaching by 52% in homogenized (packed) soil columns (p=0.0298). Biochar additions in undisturbed soil columns did not significantly (p>0.05) reduce atrazine leaching. Mean peak groundwater atrazine concentrations were 53% lower in a field experiment after additions of 10 t ha(-1) acidified biochar (p=0.0056) relative to no biochar additions. Equivalent peat applications by dry mass had no effect on atrazine leaching. Plots receiving a peat-biochar mixture showed no reduction, suggesting that the peat organic matter may compete with atrazine for biochar sorption sites. Several individual measurement values outside the 99% confidence interval in perched groundwater concentrations indicate that macropore structure could contribute to rare, large leaching events that are not effectively reduced by biochar. We conclude that biochar application has the potential to decrease peak atrazine leaching, but heterogeneous soil conditions, especially preferential flow paths, may reduce this impact. Long-term atrazine leaching reductions are also uncertain. PMID:24129000

  13. PRESERVATIVE LEACHING FROM WEATHERED CCA-TREATED WOOD

    Science.gov (United States)

    Disposal of discarded CCA-treated wood in landfills raises concerns with respect to leaching of preservative compounds. When unweathered CCA-treated wood is leached using the toxicity characteristic leaching procedure (TCLP), arsenic concentrations exceed the toxicity characteris...

  14. Mouse kidney transplantation: models of allograft rejection.

    Science.gov (United States)

    Tse, George H; Hesketh, Emily E; Clay, Michael; Borthwick, Gary; Hughes, Jeremy; Marson, Lorna P

    2014-01-01

    Rejection of the transplanted kidney in humans is still a major cause of morbidity and mortality. The mouse model of renal transplantation closely replicates both the technical and pathological processes that occur in human renal transplantation. Although mouse models of allogeneic rejection in organs other than the kidney exist, and are more technically feasible, there is evidence that different organs elicit disparate rejection modes and dynamics, for instance the time course of rejection in cardiac and renal allograft differs significantly in certain strain combinations. This model is an attractive tool for many reasons despite its technical challenges. As inbred mouse strain haplotypes are well characterized it is possible to choose donor and recipient combinations to model acute allograft rejection by transplanting across MHC class I and II loci. Conversely by transplanting between strains with similar haplotypes a chronic process can be elicited were the allograft kidney develops interstitial fibrosis and tubular atrophy. We have modified the surgical technique to reduce operating time and improve ease of surgery, however a learning curve still needs to be overcome in order to faithfully replicate the model. This study will provide key points in the surgical procedure and aid the process of establishing this technique.

  15. Leaching of tritium from a cement composite

    International Nuclear Information System (INIS)

    Leaching of tritium from cement composites into an aqueous phase has been studied to evaluate the safety of incorporation of the tritiated liquid waste into cement. Leaching tests were performed by the method recommended by the International Atomic Energy Agency. The Leaching fraction was measured as functions of waste-cement ratio (Wa/C), temperature of leachant and curing time. The tritium leachability of cement in the long term test follows the order: alumina cement portland cement slag cement. The fraction of tritium leached increases with increasing Wa/C and temperature and decreasing curing period. A deionized water as a leachant gives a slightly higher leachability than synthetic sea water. The amount leached of tritium from a 200 l drum size specimen was estimated on the basis of the above results. (author)

  16. LEACH Algorithm Based on Load Balancing

    Directory of Open Access Journals (Sweden)

    Wangang Wang

    2013-09-01

    Full Text Available This paper discusses advantages of LEACH Algorithm and the existing improved model which takes the famous hierarchy clustering routing protocol LEACH Algorithm as researching object. Then the paper indicates the problem that in the algorithm capacity factor of cluster head node is not taken into account leading the structure of clusters to be not so reasonable. This research discusses an energy-uniform cluster and cluster head selecting mechanism in which “Pseudo cluster head” concept is introduced in order to coordinate with “Load Monitor” Mechanism and “Load Leisure” Mechanism to maintain load balancing of cluster head character and stability of network topology. On the basis of LEACH Protocol improving algorithm of LEACH-C, CEFL and DCHS. NS2 simulation instrument is applied to do simulation analysis on the improved algorithm. Simulation result shows that LEACH-P Protocol effectively increase energy utilization efficiency, lengthens network lifetime and balances network load.  

  17. Rejection of pharmaceuticals by nanofiltration (NF) membranes: Effect of fouling on rejection behaviour

    Science.gov (United States)

    Mahlangu, T. O.; Msagati, T. A. M.; Hoek, E. M. V.; Verliefde, A. R. D.; Mamba, B. B.

    The aim of this study was to investigate the effects of membrane fouling by sodium alginate, latex and a combination of alginate + latex on the rejection behaviour of salts and organics. Sodium chloride and caffeine were selected to represent salts and organics, respectively. The effects of the presence of calcium chloride on the fouling behaviour and rejection of solutes were investigated. The results revealed that the salt rejection by virgin membranes was 47% while that of caffeine was 85%. Fouling by alginate, latex and combined alginate-latex resulted in flux decline of 25%, 37% and 17%, respectively. The addition of Ca2+ aggravated fouling and resulted in further flux decline to 37%. Fouling decreased salt rejection, an observation that was further aggravated by the addition on Ca2+. However, it was also observed that fouling with alginate and calcium and with latex and calcium minimised salt rejection by 30% and 31%, respectively. This reduction in salt rejection was attributed to the decrease in permeate flux (since rejection is a function of flux). There was a slight increase in caffeine rejection when the membrane was fouled with latex particles. Moreover, the presence of foulants on the membrane resulted in a decrease in the surface charge of the membrane. The results of this study have shown that the NF 270 membrane can be used to treat water samples contaminated with caffeine and other organic compounds that have physicochemical properties similar to those of caffeine.

  18. Microbial leaching of marmatite by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans

    Institute of Scientific and Technical Information of China (English)

    WANG Jun; QIU Guan-zhou; QIN Wen-qing; ZHANG Yan-sheng

    2006-01-01

    The bioleaching of marmatite in shaken flasks was studied. After leaching for 29 days, the leaching ratio of zinc was 91%.Three kinds of bacteria, mixture-based bacteria, 9K-based bacteria and sulfur-based bacteria were used in marmatite leaching, of which the mixture-based bacteria have the best leaching result while the sulfur-based bacteria have the worst. By analyzing the leaching residue using SEM and EDXA, the marmatite leaching mechanism was discussed.

  19. Bacteria heap leaching test of a uranium ore

    International Nuclear Information System (INIS)

    Column bioleaching test of a uranium ore was carried out. The optimum acidity, spraying intensity, spray-pause time ratio were determined. The potential, Fe and U concentrations in the leaching process were investigated. The effect of bacteria column leaching was compared with that of acid column leaching. The results show that bacteria column leaching can shorten leaching cycle, and the leaching rate of uranium increases by 9.7%. (authors)

  20. Dynamic leaching test of personal computer components.

    Science.gov (United States)

    Li, Yadong; Richardson, Jay B; Niu, Xiaojun; Jackson, Ollie J; Laster, Jeremy D; Walker, Aaron K

    2009-11-15

    A dynamic leaching test (DLT) was developed and used to evaluate the leaching of toxic substances for electronic waste in the environment. The major components in personal computers (PCs) including motherboards, hard disc drives, floppy disc drives, and compact disc drives were tested. The tests lasted for 2 years for motherboards and 1.5 year for the disc drives. The extraction fluids for the standard toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP) were used as the DLT leaching solutions. A total of 18 elements including Ag, Al, As, Au, Ba, Be, Cd, Cr, Cu, Fe, Ga, Ni, Pd, Pb, Sb, Se, Sn, and Zn were analyzed in the DLT leachates. Only Al, Cu, Fe, Ni, Pb, and Zn were commonly found in the DLT leachates of the PC components. Their leaching levels were much higher in TCLP extraction fluid than in SPLP extraction fluid. The toxic heavy metal Pb was found to continuously leach out of the components over the entire test periods. The cumulative amounts of Pb leached out of the motherboards in TCLP extraction fluid reached 2.0 g per motherboard over the 2-year test period, and that in SPLP extraction fluid were 75-90% less. The leaching rates or levels of Pb were largely affected by the content of galvanized steel in the PC components. The higher was the steel content, the lower the Pb leaching rate would be. The findings suggest that the obsolete PCs disposed of in landfills or discarded in the environment continuously release Pb for years when subjected to landfill leachate or rains. PMID:19616380

  1. Preventing Allograft Rejection by Targeting Immune Metabolism

    Directory of Open Access Journals (Sweden)

    Chen-Fang Lee

    2015-10-01

    Full Text Available Upon antigen recognition and co-stimulation, T lymphocytes upregulate the metabolic machinery necessary to proliferate and sustain effector function. This metabolic reprogramming in T cells regulates T cell activation and differentiation but is not just a consequence of antigen recognition. Although such metabolic reprogramming promotes the differentiation and function of T effector cells, the differentiation of regulatory T cells employs different metabolic reprogramming. Therefore, we hypothesized that inhibition of glycolysis and glutamine metabolism might prevent graft rejection by inhibiting effector generation and function and promoting regulatory T cell generation. We devised an anti-rejection regimen involving the glycolytic inhibitor 2-deoxyglucose (2-DG, the anti-type II diabetes drug metformin, and the inhibitor of glutamine metabolism 6-diazo-5-oxo-L-norleucine (DON. Using this triple-drug regimen, we were able to prevent or delay graft rejection in fully mismatched skin and heart allograft transplantation models.

  2. Dry anaerobic digestion of rejects from pre-treated food waste; Torroetning av rejekt fraan foerbehandling av matavfall

    Energy Technology Data Exchange (ETDEWEB)

    Bohn, Irene [NSR, Helsingborg (Sweden); Murto, Marika; Bjoernsson, Lovisa [Bioteknik, LTH, Lund (Sweden); Rosqvist, Haakan [Rosqvist Resurs, Klaagerup (Sweden)

    2011-11-15

    When the organic fraction of source separated municipal solid waste is digested anaerobically in a continuously stirred tank reactor there is a need for a pretreatment to make the waste pumpable and remove contaminants. In one type of pretreatment the material passes through a screw press which separates waste in a liquid fraction and a dry fraction (the reject). At NSR this technique is used and at present the reject is incinerated. A previous study has shown that about 30 % of the methane potential of the incoming organic waste can be found in the reject. The aim of the present project was to investigate the possibilities of realizing the methane potential through batch wise dry anaerobic digestion followed by composting as an alternative to incineration. In the technique used in the present project the material was digested in an anaerobic leach-bed with recirculation of leachate over the bed. It is important that the material is sufficiently porous to let the leachate spread evenly through the leach-bed. Treatment of reject and a mixture of reject and structural material were tested to investigate if the addition of structural material had an effect on the porosity. The flow of liquid through a leach-bed of reject and one of reject mixed with structural material was studied using LiBr as tracer. The digestate from the dry digestion process was composted, and the resulting compost was evaluated. The odor from the digestate, the active compost and the compost product was measured by analyzing the odor in the air of the porous space in heaps of the different materials. This was used to evaluate the risk of odor problems. The dry digestion and the tracer experiment both showed that mixing the reject with structural material had a positive effect on the flow of liquid through the material and the digestion process. Addition of structural material to the reject was needed in order to achieve an efficient digestion process. Using tracers proved to be a useful way of

  3. Video auditing techniques for breaker reject

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, B.M.; Corke, P.I.; O`Brien, G.D.; Waugh, J.M. [CSIRO (Australia). Division of Minerals

    1998-12-31

    Rotary breakers are used by many Australian coal mines to reduce the topsize of run of mine (ROM) coal to a size that can be handled by the processing plant. Coal that does not break to the designated topsize therefore passes out with the rock as breaker rejects. The degree of coal loss can be assessed manually by stop belt auditing of the reject belt, but this method is impractical for long-term monitoring of breaker rejects and breaker performance. Case studies of several open cut coal mines in the Bowen Basin of Central Queensland were made to determine the extent of the problem. The results indicated instances where significant losses did occur, but it was not possible to make an accurate estimate of the total value of the losses. This paper covers work undertaken to develop new auditing techniques for qualitative, quantitative and continuous monitoring of reject belt material which uses relatively low-cost equipment and mature technology. Initial work has concentrated on developing video surveillance techniques suitable for the range of environmental conditions typically encountered in the field. Multi-media methods are being developed for qualitative data presentation, and image analysis techniques are being investigated to extract basic quantitative information from video sequences, such as particle size and shape. Future work includes development of automatic methods using machine vision for 100% on-line inspection. The main attraction of the methodology being adopted is the potential to easily adapt the techniques to diagnostic and control functions. In situations where significant losses occur, this approach could open up many possibilities for reducing coal rejection or allowing its recovery from the rejects stream to improve productivity. 12 refs., 4 figs., 1 tab.

  4. Mesophilic leaching of copper sulphide sludge

    Directory of Open Access Journals (Sweden)

    VLADIMIR B. CVETKOVSKI

    2009-02-01

    Full Text Available Copper was precipitated using a sodium sulphide solution as the precipitation agent from an acid solution containing 17 g/l copper and 350 g/l sulphuric acid. The particle size of nearly 1 µm in the sulphide sludge sample was detected by optical microscopy. Based on chemical and X-ray diffraction analyses, covellite was detected as the major sulphide mineral. The batch bioleach amenability test was performed at 32 °C on the Tk31 mine mesophilic mixed culture using a residence time of 28 days. The dissolution of copper sulphide by direct catalytic leaching of the sulphides with bacteria attached to the particles was found to be worthy, although a small quantity of ferrous ions had to be added to raise the activity of the bacteria and the redox potential of the culture medium. Throughout the 22-day period of the bioleach test, copper recovery based on residue analysis indicated a copper extraction of 95 %, with copper concentration in the bioleach solution of 15 g/l. The slope of the straight line tangential to the exponential part of the extraction curve gave a copper solubilisation rate of 1.1 g/l per day. This suggests that a copper extraction of 95 % for the period of bioleach test of 13.6 days may be attained in a three-stage bioreactor system.

  5. Radiotracer investigation in gold leaching tanks.

    Science.gov (United States)

    Dagadu, C P K; Akaho, E H K; Danso, K A; Stegowski, Z; Furman, L

    2012-01-01

    Measurement and analysis of residence time distribution (RTD) is a classical method to investigate performance of chemical reactors. In the present investigation, the radioactive tracer technique was used to measure the RTD of aqueous phase in a series of gold leaching tanks at the Damang gold processing plant in Ghana. The objective of the investigation was to measure the effective volume of each tank and validate the design data after recent process intensification or revamping of the plant. I-131 was used as a radioactive tracer and was instantaneously injected into the feed stream of the first tank and monitored at the outlet of different tanks. Both sampling and online measurement methods were used to monitor the tracer concentration. The results of measurements indicated that both the methods provided identical RTD curves. The mean residence time (MRT) and effective volume of each tank was estimated. The tanks-in-series model with exchange between active and stagnant volume was used and found suitable to describe the flow structure of aqueous phase in the tanks. The estimated effective volume of the tanks and high degree of mixing in tanks could validate the design data and confirmed the expectation of the plant engineer after intensification of the process.

  6. Solar dynamic space power system heat rejection

    Science.gov (United States)

    Carlson, A. W.; Gustafson, E.; Mclallin, K. L.

    1986-01-01

    A radiator system concept is described that meets the heat rejection requirements of the NASA Space Station solar dynamic power modules. The heat pipe radiator is a high-reliability, high-performance approach that is capable of erection in space and is maintainable on orbit. Results are present of trade studies that compare the radiator system area and weight estimates for candidate advanced high performance heat pipes. The results indicate the advantages of the dual-slot heat pipe radiator for high temperature applications as well as its weight-reduction potential over the range of temperatures to be encountered in the solar dynamic heat rejection systems.

  7. Leaching kinetics of molybdenum from Ni-Mo ore in sulfuric acid solution with sodium peroxodisulfate as oxidant

    Institute of Scientific and Technical Information of China (English)

    刘志雄; 尹周澜; 陈义光; 熊利芝

    2015-01-01

    The leaching kinetics of molybdenum from Ni-Mo ore in sulfuric acid solution with sodium peroxodisulfate was studied. The effects including leaching temperature, reaction time, particle size, stirring speed, and concentrations of sulfuric acid and sodium peroxodisulfate were investigated. The leaching process of molybdenum from Ni-Mo ore is controlled by the chemical reaction through the solid layer across the unreacted shrinking core. The apparent activation energy of the leaching of molybdenum is calculated to be 41.0 kJ/mol and the leaching kinetics equation of molybdenum from Ni-Mo ore is expressed as 1−(1−a)1/3=3405.7exp[−41030.0/(RT)]t.

  8. Suppressing Heavy Metal Leaching through Ball Milling of Fly Ash

    Directory of Open Access Journals (Sweden)

    Zhiliang Chen

    2016-07-01

    Full Text Available Ball milling is investigated as a method of reducing the leaching concentration (often termed stablilization of heavy metals in municipal solid waste incineration (MSWI fly ash. Three heavy metals (Cu, Cr, Pb loose much of their solubility in leachate by treating fly ash in a planetary ball mill, in which collisions between balls and fly ash drive various physical processes, as well as chemical reactions. The efficiency of stabilization is evaluated by analysing heavy metals in the leachable fraction from treated fly ash. Ball milling reduces the leaching concentration of Cu, Cr, and Pb, and water washing effectively promotes stabilization efficiency by removing soluble salts. Size distribution and morphology of particles were analysed by laser particle diameter analysis and scanning electron microscopy. X-ray diffraction analysis reveals significant reduction of the crystallinity of fly ash by milling. Fly ash particles can be activated through this ball milling, leading to a significant decrease in particle size, a rise in its BET-surface, and turning basic crystals therein into amorphous structures. The dissolution rate of acid buffering materials present in activated particles is enhanced, resulting in a rising pH value of the leachate, reducing the leaching out of some heavy metals.

  9. Characterizing the Leaching Behavior of Coal Combustion Residues using the Leaching Environmental Assessment Framework (LEAF) to Inform Future Management Decisions

    Science.gov (United States)

    Abstract for presentation on Characterizing the Leaching Behavior of Coal Combustion Residues using the Leaching Environmental Assessment Framework (LEAF) to Inform Future Management Decisions. The abstract is attached.

  10. Increasing the efficiency of solute leaching: impacts of flow interruption with drainage of the ``preferential flow paths''

    Science.gov (United States)

    Cote, C. M.; Bristow, K. L.; Ross, P. J.

    2000-05-01

    Most soils contain preferential flow paths that can impact on solute mobility. Solutes can move rapidly down the preferential flow paths with high pore-water velocities, but can be held in the less permeable region of the soil matrix with low pore-water velocities, thereby reducing the efficiency of leaching. In this study, we conducted leaching experiments with interruption of the flow and drainage of the main flow paths to assess the efficiency of this type of leaching. We compared our experimental results to a simple analytical model, which predicts the influence of the variations in concentration gradients within a single spherical aggregate (SSA) surrounded by preferential flow paths on leaching. We used large (length: 300 mm, diameter: 216 mm) undisturbed field soil cores from two contrasting soil types. To carry out intermittent leaching experiments, the field soil cores were first saturated with tracer solution (CaBr 2), and background solution (CaCl 2) was applied to mimic a leaching event. The cores were then drained at 25- to 30-cm suction to empty the main flow paths to mimic a dry period during which solutes could redistribute within the undrained region. We also conducted continuous leaching experiments to assess the impact of the dry periods on the efficiency of leaching. The flow interruptions with drainage enhanced leaching by 10-20% for our soils, which was consistent with the model's prediction, given an optimised "equivalent aggregate radius" for each soil. This parameter quantifies the time scales that characterise diffusion within the undrained region of the soil, and allows us to calculate the duration of the leaching events and interruption periods that would lead to more efficient leaching. Application of these methodologies will aid development of strategies for improving management of chemicals in soils, needed in managing salts in soils, in improving fertiliser efficiency, and in reclaiming contaminated soils.

  11. Leaching studies for tin recovery from waste e-scrap.

    Science.gov (United States)

    Jha, Manis Kumar; Choubey, Pankaj Kumar; Jha, Amrita Kumari; Kumari, Archana; Lee, Jae-Chun; Kumar, Vinay; Jeong, Jinki

    2012-10-01

    Printed circuit boards (PCBs) are the most essential components of all electrical and electronic equipments, which contain noteworthy quantity of metals, some of which are toxic to life and all of which are valuable resources. Therefore, recycling of PCBs is necessary for the safe disposal/utilization of these metals. Present paper is a part of developing Indo-Korean recycling technique consists of organic swelling pre-treatment technique for the liberation of thin layer of metallic sheet and the treatment of epoxy resin to remove/recover toxic soldering material. To optimize the parameters required for recovery of tin from waste PCBs, initially the bench scale studies were carried out using fresh solder (containing 52.6% Sn and 47.3% Pb) varying the acid concentration, temperature, mixing time and pulp density. The experimental data indicate that 95.79% of tin was leached out from solder material using 5.5M HCl at fixed pulp density 50 g/L and temperature 90°C in mixing time 165 min. Kinetic studies followed the chemical reaction controlled dense constant size cylindrical particles with activation energy of 117.68 kJ/mol. However, 97.79% of tin was found to be leached out from solder materials of liberated swelled epoxy resin using 4.5M HCl at 90°C, mixing time 60 min and pulp density 50 g/L. From the leach liquor of solder materials of epoxy resin, the precipitate of sodium stannate as value added product was obtained at pH 1.9. The Pb from the leach residue was removed by using 0.1M nitric acid at 90°C in mixing time 45 min and pulp density 10g/L. The metal free epoxy resin could be disposed-of safely/used as filling material without affecting the environment.

  12. Leaching dynamics of uranium in a contaminated soil site

    International Nuclear Information System (INIS)

    Samples from a potentially contaminated industrial area were analyzed for uranium using neutron activation analysis (NAA). Uranium concentration values had a typical uncertainty of 2 % and a detection limit of 1 Bq/kg. To investigate the potential leaching dynamics into ground water two techniques were employed. The US EPA Toxicity Characterization Leaching Procedure (TCLP) and the Sequential Extraction Procedure (SEP) were used to determine the concentration of uranium in the leachates. TCLP and SEP showed that very little of the uranium leached into solution under different chemical conditions. Values of uranium leachates ranged from 0.05 to 3.5 Bq/L; a concentration much lower than the results found in the soil concentrations which ranged from 29 to 155 Bq/kg. NAA showed an 8 % uncertainty for leachates with a detection limit of 0.13 Bq/L. To mimic environmental conditions and acid rain, pH 4.3 water was used as the extraction solvent instead of the acetic acid routinely used in TCLP. Results confirmed that very low amounts of uranium leached with values ranging from 0.0002 to 0.0122 Bq/L. These values represent 0.01-1 % of the uranium in the soil samples. The distribution of uranium in soil according to particle size was also investigated to evaluate its potential movement and possible contamination of the water table. Particles below 250 μm in diameter showed a linear increase in uranium concentration whereas those with a larger diameter had constant uranium content. (author)

  13. Biocide leaching from CBA treated wood — A mechanistic interpretation

    International Nuclear Information System (INIS)

    Treated wood is frequently used for construction. However, there is a need to ensure that biocides used for the treatment are not a threat for people or environment. The paper focused on Pinus sylvestris treated with copper–boron–azole (CBA), containing tebuconazole as organic biocide and monoethanolamine (Mea). This study investigates chemical mechanisms of fixation and mobilisation involved in the leaching process of the used inorganic and organic biocides in CBA. A pH dependent leaching test was performed, followed by a set of complementary analysis methods in order to identify and quantify the species released from wood. The main findings of this study are: -Organic compounds are released from untreated and treated wood; the quantity of released total organic carbon, carboxylic and phenolic functions increasing with the pH. -Nitrogen containing compounds, i.e. mainly Mea and its reaction products with extractives, are released in important quantities from CBA treated wood, especially at low pH. -The release of copper is the result of competitive reactions: fixation via complexation reactions and complexation with extractives in the liquid phase. The specific pH dependency of Cu leaching is explained by the competition of ligands for protonation and complexation. -Tebuconazole is released to a lesser extent relative to its initial content. Its fixation on solid wood structure seems to be influenced by pH, suggesting interactions with -OH groups on wood. Boron release appears to be pH independent and very high. This confirms its weak fixation on wood and also no or weak interaction with the extractives. - Highlights: ► A pH dependent leaching mechanism for CBA treated wood is described. ► The fixation and mobilisation of inorganic and organic biocides was investigated. ► Extractives' quantity and nature depend on pH. ► Competition of ligands for protonation and complexation explains Cu behaviour. ► Tebuconazole seems to interact with -OH groups on

  14. ALKALINE CARBONATE LEACHING PROCESS FOR URANIUM EXTRACTION

    Science.gov (United States)

    Thunaes, A.; Brown, E.A.; Rabbitts, A.T.

    1957-11-12

    A process for the leaching of uranium from high carbonate ores is presented. According to the process, the ore is leached at a temperature of about 200 deg C and a pressure of about 200 p.s.i.g. with a solution containing alkali carbonate, alkali permanganate, and bicarbonate ion, the bicarbonate ion functionlng to prevent premature formation of alkali hydroxide and consequent precipitation of a diuranate. After the leaching is complete, the uranium present is recovered by precipitation with NaOH.

  15. Leaching from municipal solid waste incineration residues

    Energy Technology Data Exchange (ETDEWEB)

    Hyks, J.

    2008-02-15

    Leaching of pollutants from Municipal Solid Waste Incineration (MSWI) residues has been investigated combining a range of laboratory leaching experiments with geochemical modeling. Special attention was paid to assessing the applicability of laboratory data for subsequent modeling with respect to presumed full-scale conditions; both sample pretreatment and actual influence of leaching conditions on the results of laboratory experiments were considered. It was shown that sample pretreatment may have large impact on leaching test data. In particular, a significant fraction of Pb was shown mobile during the washing of residues with water. In addition, drying of residues (i.e. slow oxidation) prior to leaching experiments increased the leaching of Cr significantly. Significant differences regarding the leaching behavior of individual elements with respect to (non)equilibrium conditions in column percolation experiments were observed in the study. As a result, three groups of elements were identified based on the predominant leaching control and the influence of (non)equilibrium on the results of the laboratory column experiments: I. Predominantly availability-controlled elements (e.g. Na, K, Cl) II. Solubility-controlled elements (e.g. Ca, S, Si, Al, Ba, and Zn) III. Complexation-controlled elements (e.g. Cu and Ni) With respect to the above groups it was suggested that results of laboratory column experiments can, with consideration, be used to estimate full-scale leaching of elements from Group I and II. However, in order to avoid large underestimations in the assessment of leaching from Group III, it is imperative to describe the time-dependent transport of dissolved organic carbon (DOC) in the tested system or to minimize the physical non-equilibrium during laboratory experiments (e.g. bigger column, slower flow velocity). Forward geochemical modeling was applied to simulate long-term release of elements from a MSWI air-pollution-control residue. Leaching of a

  16. 热酸浸出锌浸渣中镓锗的研究%Extracting Gallium and Germanium from Zinc-leaching Residues by Hot-acid Leaching Process

    Institute of Scientific and Technical Information of China (English)

    马喜红; 覃文庆; 吴雪兰; 任浏祎

    2012-01-01

    研究了锌浸渣热酸浸出过程的工艺条件,分析了浸出热力学和动力学机理,并用于指导回收稀有金属镓和锗.实验结果表明,锌浸渣中镓和锗浸出的最佳工艺条件为:硫酸初始质量浓度为188 g/L,反应温度为95℃,反应时间为3h,液固比为5∶1,搅拌速度为300 r/min,该条件下多组综合实验的酸浸出液中Ga和Ge的浸出率均高于86%和62%.锌浸渣中金属镓锗的浸出过程在动力学上属于“未反应核减缩”模型,浸出过程主要受反应温度、始酸浓度、反应时间的影响,反应由界面化学反应控制.%Extraction of gallium and germanium from zinc leaching residue was carried out by hot-acid leaching. The effects of leaching agent ( sulfuric acid) , leaching temperature, leaching time, L/S ratio and agitation speed on the leaching rate of Ga and Ge were examined, while the thermodynamics and dynamic mechanism for the leaching were, also analyzed. Results showed that the optimal leaching conditions were as follows: the initial mass concentration of sulfuric acid was 188 g/L, leaching temperature was 95 ℃ , leaching time was 3 h, L/S ratio was 5:1, and agitation speed was 300 r/min. Under these conditions, the leaching rates of Ga and Ge in acid leaching solution from multi-group comprehensive tests were averagely above 86% and 62% , respectively. Furthermore, the leaching process of Ga and Ge follows the kinetic law of "shrinking of unreacted core" , mainly influenced by leaching temperature, concentration of sulfuric acid and leaching time, also being controlled by interface chemical reaction.

  17. Rejection Pathways in Heart Transplant Recipients

    NARCIS (Netherlands)

    N.M. van Besouw (Nicole)

    1999-01-01

    textabstractSince the beginning of this century experimental heart transplantations in animal studies were performed.' These studies were started in Rotterdam in the seventies to compare heterotopic and orthotopic heart transplantations, and to study the process of chronic rejection. The history of

  18. Waste heat rejection from geothermal power stations

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, R.C.

    1978-12-01

    This study of waste heat rejection from geothermal power stations is concerned only with the heat rejected from the power cycle. The heat contained in reinjected or otherwise discharged geothermal fluids is not included with the waste heat considered here. The heat contained in the underflow from the flashtanks in such systems is not considered as part of the heat rejected from the power cycle. By following this definition of the waste heat to be rejected, various methods of waste heat dissipation are discussed without regard for the particular arrangement to obtain heat from the geothermal source. Recent conceptual design studies made for 50-MW(e) geothermal power stations at Heber and Niland, California, are of particular interst. The former uses a flashed-steam system and the latter a binary cycle that uses isopentane. In last-quarter 1976 dollars, the total estimated capital costs were about $750/kW and production costs about 50 mills/kWhr. If wet/dry towers were used to conserve 50% of the water evaporation at Heber, production costs would be about 65 mills/kWhr.

  19. Development of enhanced sulfur rejection processes

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, R.H.; Luttrell, G.H.; Adel, G.T.; Richardson, P.E.

    1996-03-01

    Research at Virginia Tech led to the development of two complementary concepts for improving the removal of inorganic sulfur from many eastern U.S. coals. These concepts are referred to as Electrochemically Enhanced Sulfur Rejection (EESR) and Polymer Enhanced Sulfur Rejection (PESR) processes. The EESR process uses electrochemical techniques to suppress the formation of hydrophobic oxidation products believed to be responsible for the floatability of coal pyrite. The PESR process uses polymeric reagents that react with pyrite and convert floatable middlings, i.e., composite particles composed of pyrite with coal inclusions, into hydrophilic particles. These new pyritic-sulfur rejection processes do not require significant modifications to existing coal preparation facilities, thereby enhancing their adoptability by the coal industry. It is believed that these processes can be used simultaneously to maximize the rejection of both well-liberated pyrite and composite coal-pyrite particles. The project was initiated on October 1, 1992 and all technical work has been completed. This report is based on the research carried out under Tasks 2-7 described in the project proposal. These tasks include Characterization, Electrochemical Studies, In Situ Monitoring of Reagent Adsorption on Pyrite, Bench Scale Testing of the EESR Process, Bench Scale Testing of the PESR Process, and Modeling and Simulation.

  20. Large Solar-Rejection Filter

    Science.gov (United States)

    Roberts, William; Sheikh, David; Patrick, Brian

    2007-01-01

    NASA utilized Image Intensified Video Cameras for ATV data acquisition from a jet flying at 12.8 km. Afterwards the video was digitized and then analyzed with a modified commercial software package, Image Systems Trackeye. Astrometric results were limited by saturation, plate scale, and imposed linear plate solution based on field reference stars. Time-dependent fragment angular trajectories, velocities, accelerations, and luminosities were derived in each video segment. It was evident that individual fragments behave differently. Photometric accuracy was insufficient to confidently assess correlations between luminosity and fragment spatial behavior (velocity, deceleration). Use of high resolution digital video cameras in future should remedy this shortcoming. A scenically accurate description of matter interpreted as a substance made up of corpuscular constituents was established during the course of the 19th century. In this description, atoms--the building blocks of the matter--form molecules. The properties of the molecules were described by chemistry or thermodynamics depending on what characteristics of the matter were investigated. In both theories, the molecules can dissociate to atoms when the kinetic energies of the atoms exceed the strength of the chemical bonds. The number of atoms is always preserved in a closed system. This is not true, however, when the matter takes up much higher energies at relativistic scales. New particles can be produced at the expense of the kinetic energy. The number of particles is no longer preserved. There are other conserved quantities, however, these quantities, the charge, baryon number, lepton number, are associated with particles that are considered elementary today. The properties and behavior of these elementary particles is the subject of Particle Physics or High Energy Physics. Practice Page: A crewmember touching a positively charged surface was thought to be galvanically isolated from the vehicle ground

  1. [Salinity change and its impact on heavy metals during beach soil leaching and desalination].

    Science.gov (United States)

    Liu, Ya-Nan; Li, Qu-Sheng; Du, Ye-Feng; Cui, Zhi-Hong; Li, Sha

    2011-07-01

    The salinity ion in soil pore water and the heavy metal content in soil as well as the heavy metal speciation were investigated in various stages of desalination during an experiment of leaching beach soil. Results show that salinity ion including Na+, K+, Mg2+, Ca2+, Cl- and SO4(2-) decreased by 80.3%, 73.5%, 86.6%, 90%, 81.8%, 98.2%. respectively compared to pre-leaching. The amount of total salt decreased by 81.6%. However, the main chemical compound in pore water was NaCl throughout the leaching experiment. The pH value of pore water increased with leaching time. Besides, the reductions of heavy metals after leaching were: Cd 26.6%, Pb 22.8%, Cu 16.9%, Cr 7.9%, Zn 9.1%. The concentrations of Pb, Cr, Cu, Zn and Cd in carbonate bound form decreased by 77.8%, 61.7%, 68.4%, 67.1% and 7.1% respectively. The contents of Cd and Pb bound to Fe-Mn oxide decreased by 49.1%, 23.5% respectively. The different mobility of salinity ions in the pore water resulted in the proportion change of each ion. Meanwhile the Eh value of the soil changed in the leaching process. All these factors resulted in the change of heavy metal speciation and the removal of heavy metals in the soil.

  2. Estimating subsoil resistance to nitrate leaching from easily measurable pedological properties

    Directory of Open Access Journals (Sweden)

    Fábio Keiti Nakagawa

    2012-11-01

    Full Text Available Leaching of nitrate (NO3- can increase the groundwater concentration of this anion and reduce the agronomical effectiveness of nitrogen fertilizers. The main soil property inversely related to NO3- leaching is the anion exchange capacity (AEC, whose determination is however too time-consuming for being carried out in soil testing laboratories. For this reason, this study evaluated if more easily measurable soil properties could be used to estimate the resistance of subsoils to NO3- leaching. Samples from the subsurface layer (20-40 cm of 24 representative soils of São Paulo State were characterized for particle-size distribution and for chemical and electrochemical properties. The subsoil content of adsorbed NO3- was calculated from the difference between the NO3- contents extracted with 1 mol L-1 KCl and with water; furthermore, NO3- leaching was studied in miscible displacement experiments. The results of both adsorption and leaching experiments were consistent with the well-known role exerted by AEC on the nitrate behavior in weathered soils. Multiple regression analysis indicated that in subsoils with (i low values of remaining phosphorus (Prem, (ii low soil pH values measured in water (pH H2O, and (iii high pH values measured in 1 moL L-1 KCl (pH KCl, the amounts of surface positive charges tend to be greater. For this reason, NO3- leaching tends to be slower in these subsoils, even under saturated flow condition.

  3. Leaching of seven pesticides currently used in cotton crop in Mato Grosso State-Brazil.

    Science.gov (United States)

    Martins, Eucarlos L; Weber, Oscarlina L S; Dores, Eliana F G C; Spadotto, Cláudio A

    2007-11-01

    This study aimed to evaluate the leaching of pesticides and the applicability of the Attenuation Factor (AF) Model to predict their leaching. The leaching of carbofuran, carbendazim, diuron, metolachlor, alpha and beta endosulfan and chlorpyrifos was studied in an Oxisol using a field experiment lysimeter located in Dom Aquino-Mato Grosso. The samples of percolated water were collected by rain event and analyzed. Chemical and physical soil attributes were determined before pesticide application to the plots. The results showed that carbofuran was the pesticide that presented a higher leaching rate in the studied soil, so was the one representing the highest contamination potential. From the total carbofuran applied in the soil surface, around 6% leached below 50 cm. The other pesticides showed lower mobility in the studied soil. The calculated values to AF were 7.06E-12 (carbendazim), 5.08E-03 (carbofuran), 3.12E-17 (diuron), 6.66E-345 (alpha-endosulfan), 1.47E-162 (beta-endosulfan), 1.50E-06 (metolachlor), 3.51E-155 (chlorpyrifos). AF Model was useful to classify the pesticides' potential for contamination; however, that model underestimated pesticide leaching. PMID:17978955

  4. Watchdog-LEACH: A new method based on LEACH protocol to Secure Clustered Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Rohbanian

    2013-07-01

    Full Text Available Wireless sensor network comprises of small sensor nodes with limited resources. Clustered networks have been proposed in many researches to reduce the power consumption in sensor networks. LEACH is one of the most interested techniques that offer an efficient way to minimize the power consumption in sensor networks. However, due to the characteristics of restricted resources and operation in a hostile environment, WSNs are subjected to numerous threats and are vulnerable to attacks. This research proposes a solution that can be applied on LEACH to increase the level of security. In Watchdog-LEACH, some nodes are considered as watchdogs and some changes are applied on LEACH protocol for intrusion detection. Watchdog-LEACH is able to protect against a wide range of attacks and it provides security, energy efficiency and memory efficiency. The result of simulation shows that in comparison to LEACH, the energy overhead is about 2% so this method is practical and can be applied to WSNs.

  5. [Influence of ammonia on leaching behaviors of incineration fly ash and its geochemical modeling].

    Science.gov (United States)

    Guan, Zhen-Zhen; Chen, De-Zhen; Thomas, Astrup

    2013-06-01

    Incineration fly ash could be contaminated with NH3 that was slipped from the ammonia-based selective non-catalytic reduction(SNCR) process and from evaporation of municipal solid wastes' leachate involved in the wastes. This research was conducted to investigate the impacts of ammonia on leaching of dissolved organic carbon (DOC) and metals from incineration fly ash in the pH range of 3.66-12.44 with an active ammonia spike. A geochemical modeling software Visual MINTEQ was adopted to calculate the chemical speciation of metals under the leaching conditions to reveal the mechanism behind the impacts. It was proved that at pH > 9, the leaching of DOC increased significantly in the presence of high concentrations of ammonia (> or = 1 357 mg x L(-1)), but there was little effect when the ammonia level in eluates was not higher than 537 mg x L(-1). At pH or = 3 253 mg x L(-1)) mobilized Cd, Cu, Ni and Zn significantly due to the formation of soluble metal-ammonia complexes, and the leaching rates reached their peaks at pH around 9; however, ammonia had little impacts on Al and Pb leaching within this pH range. At pH > 12, for Cd, Cu, Ni and Zn, their leaching species were predominantly in the form of hydroxide complexes. Under the ammonia concentration of 3253 mg x L(-1), the Visual MINTEQ modeling results were compared with the experimental data, and it was proved that the leaching of Al, Pb and Zn was mainly controlled by precipitation/dissolution modeling, while Cd, Cu and Ni were controlled by precipitation/dissolution and surface complexation/precipitation processes; Visual MINTEQ modeling could well describe the leaching behaviors of Al, Cu, Pb and Zn from incineration fly ash. PMID:23947071

  6. Role of minerals properties on leaching process of weathered crust elution-deposited rare earth ore

    Institute of Scientific and Technical Information of China (English)

    肖燕飞; 刘向生; 冯宗玉; 黄小卫; 黄莉; 陈迎迎; 吴文远

    2015-01-01

    Granite belonged to intrusive rock and volcanic was extrusive rock. There may be many differences in their degree of weathering and mineral chemical composition. The present study investigated the minerals properties and the leaching mechanism of the granitic weathered crust elution-deposited rare earth ore from Longnan Rare Earth Mine area (LN ores) and volcanic weathered crust elution-deposited rare earth ore from Liutang Rare Earth Mine area (LT ores). The X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) were used to characterize the phase of rare earth ores. The particle size distributions and main composition of the ore were also presented in this paper. The leaching mechanisms of two kinds of rare earth ores were analyzed with different kinetics models and could be described by the shrinking-core model. They were all inner diffusion-controlled leaching processes. The leaching equation of the kinetics of the LN ores could be expressed as:4 LN LN 1.096 10 2/3 0.377 8.314 0 2 3=0.1061 (1 ) Tr e tη η×−−− − −, leaching equation of kinetics of LT ores was 3 LT LT 4.640 10 2/3 0.411 8.314 0 32 3=8.33 101 (1 ) Tr e tη η×−− −×− − −. The rare earth leaching rate of LT ores was always lower in the same condition, and it would need more time and more (NH4)2SO4 consump-tion to achieve the same rare earth leaching efficiency, which would lead to more serious ammonia-nitrogen pollution. Therefore, magnesium salt was proposed as the leaching agent to eliminate ammonia-nitrogen pollution and further studies would be taken in the future.

  7. Leach-SX-EW copper revalorization from overburden of abandoned copper mine Cerovo, Eastern Serbia

    Directory of Open Access Journals (Sweden)

    Stevanović Z.

    2009-01-01

    Full Text Available Hydrometallurgical processes for copper revalorization from overburden of abandoned mine Cerovo in Eastern Serbia were studied. Paper contain results of percolation leaching tests, performed with acidic mine waters accumulated in the bottom of the former open pit, followed by solvent extraction (SX and electrowinning (EW processes on achieved copper pregnant leach solutions. Usage of accumulated waste waters was objected to minimizing the environmental hazard due to uncontrolled leaking of these waters in nearby creeks and rivers. Chemical composition of acidic mine waters used for leaching tests was: (g/dm3: Cu - 0.201; Fe - 0.095; Mn - 0.041; Zn - 0.026; Ni - 0.0004; pH value - 3.3. Copper content in overburden sample used for leaching tests was 0.21% from which 64% were oxide copper minerals. In scope of leaching tests were examined influence of leaching solution pH values and iron (III concentration on copper recovery. It was established that for 120 hours of leaching on pH=1.5 without oxidant agents, copper concentration in pregnant leach solutions enriched up to 1.08g/dm3 which was enough for copper extraction from solution with SX-EW treatment. As extraction reagent in SX circuit was used LIX-984N in a kerosene diluent. Cathode current density in electrowinning cell was 220Am-2 while electrolyte temperature was kept on 50±2oC. Produced cathode copper at the end of SX-EW process has purity of 99.95% Cu.

  8. The geopolitical implications of the House of Commons’ decision to reject military intervention in Syria

    OpenAIRE

    Ulrichsen, Kristian Coates

    2015-01-01

    In August 2013, the House of Commons rejected a Government proposal to intervene in the Syrian conflict following that country’s regime’s use of chemical weapons. Here, Dr Kristian Coates Ulrichsen assesses the geopolitical implications of that dramatic night in the House of Commons, arguing that it decisively stopped the momentum towards war.

  9. Effect of Tetrachloroethylene on Sphalerite Leaching

    Institute of Scientific and Technical Information of China (English)

    王兴尧; 彭鹏; 谢慧琴; 卢立柱

    2004-01-01

    The effects of tetrachloroethylene (C2C14) on sphalerite leaching in FeCl3-HCl wereinvestigated in view of simultaneous mass transfer and reaction, and the leaching models with andwithout organic solvent C2Cl4 were derived. The leaching experiments and the SEM results show thatC2C14 is an effective organic solvent for sphalerite leaching in FeC13-HC1 system to be accelerated andfor the sulfur to be separated. Adding C2C14 in the FeCl3-HC1 medium will turn the kinetic modelcontrolled by sulfur layer diffusion with process activation energy of 67.9 kJ/mol into mixed diffusionwith the energy reduced to 55.1 kJ/mol when 20 ml of C2C14 was added.

  10. Alternative leaching processes for uranium ores

    International Nuclear Information System (INIS)

    Laboratory studies have been carried out to compare the extraction of uranium from Australian ores by conventional leaching in sulphuric acid with that obtained using hydrochloric acid and acidified ferric sulphate solutions. Leaching with hydrochloric acid achieved higher extractions of radium-226 but the extraction of uranium was reduced considerably. The use of acidified ferric sulphate solution reduced acid consumption by 20-40% without any detrimental effect on uranium extraction. The ferric ion, which is reduced during leaching, can be reoxidized and recycled after the addition of acid makeup. Hydrogen peroxide was found to be an effective oxidant in conventional sulphuric acid leaching. It is more expensive than alternative oxidants, but it is non-polluting, lesser quantities are required and acid consumption is reduced

  11. YACON INULIN LEACHING DURING HOT WATER BLANCHING

    OpenAIRE

    Caroline Fenner Scher; Adriano Brandelli; Caciano Zapata Noreña

    2015-01-01

    ABSTRACTYacon roots contain inulin, which has prebiotic properties and it may be used as sucrose or fat substitutes. However, inulin is very soluble in water. The loss of this important nutrient during blanching is caused mainly by diffusion or leaching, which might be diminished if blanching temperature - time conditions are correctly employed. The aim of this study was to determine the leaching of the sugars inulin, glucose and fructose, present in yacon roots, during hot water blanching un...

  12. Treatment of cadmium dust with two-stage leaching process

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The treatment of cadmium dust with a two-stage leaching process was investigated to replace the existing sulphation roast-leaching processes. The process parameters in the first stage leaching were basically similar to the neutralleaching in zinc hydrometallurgy. The effects of process parameters in the second stage leaching on the extraction of zincand cadmium were mainly studied. The experimental results indicated that zinc and cadmium could be efficiently recoveredfrom the cadmium dust by two-stage leaching process. The extraction percentages of zinc and cadmium in two stage leach-ing reached 95% and 88% respectively under the optimum conditions. The total extraction percentage of Zn and Cdreached 94%.

  13. Heat transfer law in leaching dump

    Institute of Scientific and Technical Information of China (English)

    WU Ai-xiang; WANG Hong-jiang; XI Yong; YANG Bao-hua; LI Jian-feng; YIN Sheng-hua; ZHA Ke-bing

    2005-01-01

    Based on the law of temperature changes in the leaching dump and the forming process of heat flux, the basic balance equation of heat flow in dump was established, the dissipated heat flow from dump to the atmosphere was analyzed to estimate the surface temperature of the ore particle in dump and discover the law of forced heat convection of heat flow transfer in dump. And the lixiviate flow formula taking a certain heat flow out of dump was deduced by using the inversion method. Through theoretic analysis, combining Dexing copper mine heap leaching production practice, the results show that the heat flow of chalcopyrite leaching emitted is not so great, but the heat flow of pyrite leaching and sulphur oxidation produced take up a higher proportion of total heat flow; the dissipated heat flow takes up a lower proportion, and most of heat flow is absorbed by itself, thus the inside temperature rises gradually; and the saturation flow form for leaching is adopted, which makes the lixiviate seepage in the transitional flow or even in the turbulent flow, so as to accelerate the heat flow diffusing and keep the leaching dump temperature suitable for bacteria living.

  14. Zinc Leaching from Tire Crumb Rubber

    Science.gov (United States)

    Rhodes, E. P.; Ren, J.; Mays, D. C.

    2010-12-01

    Recent estimates indicate that more than 2 billion scrap tires are currently stockpiled in the United States and approximately 280 million more tires are added annually. Various engineering applications utilize recycled tires in the form of shredded tire crumb rubber. However, the use of tire crumb rubber may have negative environmental impacts, especially when the rubber comes into contact with water. A review of the literature indicates that leaching of zinc from tire crumb rubber is the most significant water quality concern associated with using this material. Zinc is generally used in tire manufacturing, representing approximately 1.3% of the final product by mass. This study will report results from the U.S. Environmental Protection Agency’s (EPA’s) Synthetic Precipitation Leaching Procedure, batch leaching tests, and column leaching tests performed to quantify the process by which zinc leaches from tire crumb rubber into water. Results are interpreted with a first-order kinetic attachment/detachment model, implemented with the U.S. Agricultural Research Service software HYDRUS-1D, in order to determine the circumstances when zinc leaching from tire crumb rubber would be expected to comply with the applicable discharge limits. One potential application for recycled tires is replacing sand with tire crumb rubber in granular media filters used for stormwater pollution control. For this to be a viable application, the total zinc in the stormwater discharge must be below the EPA’s benchmark value of 0.117 mg/L.

  15. Optimization of the factors that accelerate leaching

    International Nuclear Information System (INIS)

    The prediction of long-term leachability of low-level radioactive waste forms is an essential element of disposal-site performance assessment. This report describes experiments and modeling techniques used to develop an accelerated leach test that meets this need. The acceleration in leaching rates caused by the combinations of two or more factors were experimentally determined. These factors were identified earlier as being able to individually accelerate leaching. They are: elevated temperature, the size of the waste form, the ratio of the volume of leachant to the surface area of the waste form, and the frequency of replacement of the leachant. The solidification agents employed were ones that are currently used to treat low-level radioactive wastes, namely portland type I cement, bitumen, and vinyl ester-styrene. The simulated wastes, sodium sulfate, sodium tetraborate, and incinerator ash, are simplified representatives of typical low-level waste streams. Experiments determined the leaching behavior of the radionuclides of cesium (Cs-137), strontium (Sr-85), and cobalt (Co-60 or Co-57) from several different formulations of solidification agents and waste types. Leaching results were based upon radiochemical and elemental analyses of aliquots of the leachate, and on its total alkalinity and pH at various times during the experiment (up to 120 days). Solid phase analyses were carried out by Scanning/Electron Microscopy and Energy Dispersive Spectroscopy on the waste forms before and after some leaching experiments. 43 refs., 96 figs., 16 tabs

  16. MINTEQ modeling for evaluating the leaching behavior of heavy metals in MSWI fly ash

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yan; JIANG Jianguo; CHEN Maozhe

    2008-01-01

    At present, all kinds of municipal solid waste incineration (MSWI) fly ash stabilization technology has been reported and successfully applied in many countries. However, leaching procedures are very different that the technologies lack uniform standard, and it is even impossible to predict the long-term stabilization. Geochemical model can explain the environmental stabilization based on chemical phase and thermodynamic crystal structure, and it is also able to guide the development of environment-friendly stabilization technology and choosing of chemical agents. Both experiment analysis and geochemical modeling were used to study the correlation between leaching behavior of MSWI fly ash and variation of pH. Dissolution/precipitation mechanism was applied in the simulation. The result indicated that the pH-dependent leaching behavior predicted by Visual MINTEQ is well in agreement with the result of pH-dependent test. pH value of leachate can significantly change the leaching behavior of MSWI fly ash. The leaching behavior of heavy metals for Pb and Cd is controlled by dissolution/precipitation mechanism, whereas for Zn and Ni, it is effected by surface adsorption reaction over a special extent of pH value.

  17. Laboratory leach tests of phosphate/sulfate waste grout and leachate adsorption tests using Hanford sediment

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R.J.; Martin, W.J.; McLaurine, S.B.; Airhart, S.P.; LeGore, V.L.; Treat, R.L.

    1987-12-01

    An assessment of the long-term risks posed by grout disposal at Hanford requires data on the ability of grout to resist leaching of waste species contained in the grout via contact with water that percolates through the ground. Additionally, data are needed on the ability of Hanford sediment (soil) surrounding the grout and concrete vault to retard migration of any wastes released from the grout. This report describes specific laboratory experiments that are producing empirical leach rate data and leachate-sediment adsorption data for Phosphate-Sulfate Waste (PSW) grout. The leach rate and adsorption values serve as inputs to computer codes used to forecast potential risk resulting from the use of ground water containing leached species. In addition, the report discusses other chemical analyses and geochemical computer code calculations that were used to identify mechanisms that control leach rates and adsorption potential. Knowledge of the controlling chemical and physical processes provides technical defensibility for using the empirical laboratory data to extrapolate the performance of the actual grout disposal system to the long time periods of interest. 59 refs., 83 figs., 18 tabs.

  18. Laboratory leach tests of phosphate/sulfate waste grout and leachate adsorption tests using Hanford sediment

    International Nuclear Information System (INIS)

    An assessment of the long-term risks posed by grout disposal at Hanford requires data on the ability of grout to resist leaching of waste species contained in the grout via contact with water that percolates through the ground. Additionally, data are needed on the ability of Hanford sediment (soil) surrounding the grout and concrete vault to retard migration of any wastes released from the grout. This report describes specific laboratory experiments that are producing empirical leach rate data and leachate-sediment adsorption data for Phosphate-Sulfate Waste (PSW) grout. The leach rate and adsorption values serve as inputs to computer codes used to forecast potential risk resulting from the use of ground water containing leached species. In addition, the report discusses other chemical analyses and geochemical computer code calculations that were used to identify mechanisms that control leach rates and adsorption potential. Knowledge of the controlling chemical and physical processes provides technical defensibility for using the empirical laboratory data to extrapolate the performance of the actual grout disposal system to the long time periods of interest. 59 refs., 83 figs., 18 tabs

  19. Meteoric 10Be in volcanic materials and its behavior during acid-leaching

    Science.gov (United States)

    Shimaoka, Akiko; Sakamoto, Minoru; Hiyagon, Hajime; Matsuzaki, Hiroyuki; Kaneoka, Ichiro; Imamura, Mineo

    2004-08-01

    We have investigated the chemical and isotopic behavior of beryllium (Be) during acid leaching for removing meteoric 10Be in volcanic samples. Determination of the Be isotopic ratio in the leachate was carried out using accelerator mass spectrometry (AMS) and inductivity coupled plasma mass spectrometer (ICP-MS). Elemental distribution of Be and other incompatible elements including boron (B) were also examined by ion microprobe (SIMS) for a deeper understanding of their chemical behavior in volcanic samples. SIMS analysis show that Be is concentrated in the groundmass together with B. However, the behavior of their elements during acid leaching is quite different. The Be concentration decreases through progressive leaching, while the concentration of B remains constant. Furthermore, the variation in the Be isotopic ratio after acid leaching is different between the two samples, neither of which has altered minerals under microscopic observation. It is demonstrated that meteoric 10Be resides in a rather narrow region of the rock and can be removed by acid leaching with minimum loss of the main host phase of Be.

  20. Influencing factors of pyrite leaching in germ-free system

    Institute of Scientific and Technical Information of China (English)

    OU Le-ming; HE Rong-quan; FENG Qi-ming

    2007-01-01

    The effect of mineral particle size,pulp potential and category of oxidant on pyrite leaching was studied.The results show that a smaller mineral particle size leads to a higher leaching rate of pyrite, and the optimum result with pyrite leaching rate of 2.92% is obtained when mineral particle size is less than 0.037 1/mm.The pulp potential reflects the leaching process. The increase of pulp potential can improve pyrite leaching. The leaching rate and velocity of pyrite can be enhanced rapidly by adding strong oxidant. The kind and the method of adding oxidant have important effect on the pyrite leaching. Appropriate concentration of Fe3+ can enhance pyrite leaching but the precipitation generated by high concentration of ferric ion covers the surface of pyrites and prevents the leaching process.The leaching rate increases with the constant addition of H2O2.

  1. Monitoring of Acute Rejection after Orthotopic Heart Tranplantation

    Institute of Scientific and Technical Information of China (English)

    Meng chun ying; Huang ke li; Luo bin; Wen ding guo

    2006-01-01

    Objectives To study the monitoring of rejection after orthotopic heart thansplantation.Methods From 1998 to 2005, 10 othotopic heart thansplans were performed, and acute rejection was monitored by endomyocardial biopsy as well as by clinical features, ECG, ultrasonocardiography and blood serum determination of Tropin I, and by the combination of these methods, we analysed the monitoring of acute rejection after the heart transplantation. Results With the combination of clinical features, ECG, ultrasonocardiography and blood serum test, 5 occurences of acute rejection were judged in the postoperative course, which were comfirmed by endomyocardial biopsy to be 2 acute rejections in Ⅰ b degree, 3 acute rejections in Ⅲ a degree. Endomyocardial biopsy were routinely performed 21 times postoperatively in which there were 1 acute rejection in Ⅰ a degree and 5 acute rejections in Ⅰ b degree. Conclusions Acute rejection is an important factor influencing the postoperative course of heart transplantation, so it is imperative to have an intime, effective and planned monitoring procedure for acute rejection. Endomyocardial biopsy is a sensitive and reliable method in diagnosis of acute rejection, but it is invasive and probable for some complications. The noninvasive method such as clinical features, ECG,ultrasonocardiography and blood serum test can be used as additive means in the diagnosis of acute rejection.Endomyocardial biopsy should be combined with some noninvasive methods in monitoring acute rejection after the heart transplantation.

  2. Selective process of zinc extraction from spent Zn–MnO2 batteries by ammonium chloride leaching

    OpenAIRE

    Nogueira, C. A.; Margarido, F.

    2015-01-01

    Recycling of spent Zn-MnO2 batteries by hydrometallurgy is usually carried out by leaching in acid media, mainly with sulphuric acid solutions. Another type of leachant was used in this work, specifically solutions of concentrated ammonium chloride. The development of this study has relied on the prediction of the chemical behavior of the constituting phases based on data obtained from theoretical and experimental equilibrium values. The assessment of the effects of factors on leaching effici...

  3. Chronic Kidney Isograft and Allograft Rejection

    Institute of Scientific and Technical Information of China (English)

    严群; 张鹏; 杨传永

    2002-01-01

    Summary: In this study antigen-independent factor in the pathogenesis of chronic rejection of organ transplants was examined. Kidney isografts and allografts were transplanted orthotopically into bilaterally nephroectomized rat recipients and studied functionally, morphologically and immunohistologically, at serial intervals up to 52 weeks after transplantation. Allograft recipients developed progressive proteinuria after 12 weeks, with gradual renal failure ultimately leading to death. At the same time, morphological changes, including progressive arteriosclerosis and glomerulosclerosis, tubular atrophy and interstitial fibrosis, developed. Immunohistologically, macrophages infiltrated glomeruli during this period and cytokines became unregulated. Our resuits showed that antigen-independent functional and morphological changes occurred in long-term kidney isografts and mimicked those appearing much earlier in allografts that reject chronically.Initial injury and extent of functioning renal mass is suggested to be important factor for such late changes.

  4. Interference Rejection Techniques in DSSS Communication System

    Institute of Scientific and Technical Information of China (English)

    GONGXiangyang; HUGuangrui

    2003-01-01

    It is known that the narrowband interfer-ence rejection capability of a direct sequence (DS) spread spectrum (SS) system can be enhanced considerably by an interference rejection algorithm prior to correlating it with the pseudo noise (PN) sequence. For narrowband gaussian noise (NGN), the techniques in common use are transver-sal filter. It models SS signal and NGN as stationary, then utilizes temporal correlation difference between SS signal and NBL however, SS signal and NGN are cyclostation-ary (CS). CS signal has correlation in frequency domain called spectrum correlation, which can not be employed by transversal filter. In this article, SS signal and NBIare modeled as CS and FRESH filter is adopted to exploit the correlation both in time domain and frequency domain.Computer simulation shows that FRESH filter can improve the system performance considerably compared with con-ventional transversal filter.

  5. Autophagy in allografts rejection: A new direction?

    Science.gov (United States)

    Sun, Hukui; Cheng, Dayan; Ma, Yuanyuan; Wang, Huaiquan; Liang, Ting; Hou, Guihua

    2016-03-18

    Despite the introduction of new and effective immunosuppressive drugs, acute cellular graft rejection is still a major risk for graft survival. Modulating the dosage of immunosuppressive drugs is not a good choice for all patients, new rejection mechanisms discovery are crucial to limit the inflammatory process and preserve the function of the transplant. Autophagy, a fundamental cellular process, can be detected in all subsets of lymphocytes and freshly isolated naive T lymphocytes. It is required for the homeostasis and function of T lymphocytes, which lead to cell survival or cell death depending on the context. T cell receptor (TCR) stimulation and costimulator signals induce strong autophagy, and autophagy deficient T cells leads to rampant apoptosis upon TCR stimulation. Autophagy has been proved to be activated during ischemia-reperfusion (I/R) injury and associated with grafts dysfunction. Furthermore, Autophagy has also emerged as a key mechanism in orchestrating innate and adaptive immune response to self-antigens, which relates with negative selection and Foxp3(+) Treg induction. Although, the role of autophagy in allograft rejection is unknown, current data suggest that autophagy indeed sweeps across both in the graft organs and recipients lymphocytes after transplantation. This review presents the rationale for the hypothesis that targeting the autophagy pathway could be beneficial in promoting graft survival after transplantation.

  6. Heterosexual Rejection and Mate Choice: A Sociometer Perspective.

    Science.gov (United States)

    Zhang, Lin; Liu, Shen; Li, Yue; Ruan, Lu-Jun

    2015-01-01

    Previous studies about the effects of social rejection on individuals' social behaviors have produced mixed results and tend to study mating behaviors from a static point of view. However, mate selection in essence is a dynamic process, and therefore sociometer theory opens up a new perspective for studying mating and its underlying practices. Based on this theory and using self-perceived mate value in the relationship between heterosexual rejection and mate choice as a mediating role, this current study examined the effects of heterosexual rejection on mate choice in two experiments. Results showed that heterosexual rejection significantly reduced self-perceived mate value, expectation, and behavioral tendencies, while heterosexual acceptance indistinctively increased these measures. Self-perceived mate value did not serve as a mediator in the relationship between heterosexual rejection and mate expectation, but it mediated the relationship between heterosexual rejection and mating behavior tendencies toward potential objects. Moreover, individuals evaded both rejection and irrelevant people when suffering from rejection.

  7. Study of uranium leaching from industrial residues of Industrias Nucleares do Brazil S.A. (INB), Caetite, Bahia, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Formiga, Thiago S.; Morais, Carlos A., E-mail: cmorais@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Gomiero, Luiz A., E-mail: gomiero@inb.gov.b [Industrias Nucleares do Brasil S/A (INB), Caetite, BA (Brazil)

    2011-07-01

    The uraniferous district of Lagoa Real, located in the south-central region of the state of Bahia, has reserves estimated at 100,000 tons of uranium, which is enough to supply Angra I, II and III for 100 more years. The process adopted for the beneficiation of the uranium ore from Lagoa Real is heap leaching, a static process in which the ore is crushed, disposed in heaps and irrigated with a sulfuric acid solution to remove the uranium. This technique has a relatively low cost of implementation, although the yield of uranium recovery is low, with an uranium content in the leached residue of 700 {mu}g/g U{sub 3}O{sub 8} for ores with an initial content of 2,700 {mu}g/g U{sub 3}O{sub 8}. With the deepening of the mine pit, an increase in the carbonate content in the ore was noted, which required a higher acid consumption in the leaching. In order to reduce the concentration of carbonates, a study of the ore concentration by flotation column was accomplished. The flotation reject had high carbonate content, with a uranium content of about 2,300 {mu}g/g U{sub 3}O{sub 8} for flotation in one column and 1,100 {mu}g/g U{sub 3}O{sub 8} for flotation in two columns. This paper presents the study of the leaching process for the recovery of the uranium present in the residue of the heap leaching and in the carbonated residue from the flotation of the anomaly 13 ore. The results indicate the feasibility of treating the waste of the heap leaching through dynamic leaching. The study of the uranium leaching from the flotation residue through acid leaching technique indicated a recovery of 96% of uranium, however with a high consumption of acid, around 450 kg/t, showing that for this case, the most suitable technique for the process is alkaline leaching. (author)

  8. THE DIAGNOSIS OF LIVER ALLOGRAFT ACUTE REJECTION IN LIVER BIOPSIES

    Directory of Open Access Journals (Sweden)

    L. V. Shkalova

    2011-01-01

    Full Text Available We performed histological examination of 80 liver allograft biopsies, the diagnosis of acute rejection was proved in 34 cases. Histological changes in liver biopsies in different grades of acute rejection were estimated according to Banff classification 1995, 1997 and were compared with current literature data. The article deals with the question of morphological value of grading acute rejection on early and late, also we analyze changes in treat- ment tactics after morphological verification of liver allograft acute rejection

  9. Spontaneous restoration of transplantation tolerance after acute rejection

    OpenAIRE

    Miller, Michelle L.; Daniels, Melvin D.; Wang, Tongmin; Chen, Jianjun; Young, James; Xu, Jing; Wang, Ying; Yin, Dengping; Vu, Vinh; Husain, Aliya N.; Alegre, Maria-Luisa; Chong, Anita S.

    2015-01-01

    Transplantation is a cure for end-stage organ failure but, in the absence of pharmacological immunosuppression, allogeneic organs are acutely rejected. Such rejection invariably results in allosensitization and accelerated rejection of secondary donor-matched grafts. Transplantation tolerance can be induced in animals and a subset of humans, and enables long-term acceptance of allografts without maintenance immunosuppression. However, graft rejection can occur long after a state of transplant...

  10. Mechanisms involved in antibody- and complement-mediated allograft rejection

    OpenAIRE

    Wasowska, Barbara A.

    2010-01-01

    Antibody-mediated rejection has become critical clinically because this form of rejection is usually unresponsive to conventional anti-rejection therapy, and therefore, it has been recognized as a major cause of allograft loss. Our group developed experimental animal models of vascularized organ transplantation to study pathogenesis of antibody- and complement-mediated endothelial cell injury leading to graft rejection. In this review, we discuss mechanisms of antibody-mediated graft rejectio...

  11. Predicting outcome of acute kidney transplant rejection using

    NARCIS (Netherlands)

    Rekers, Niels Vincent

    2014-01-01

    Acute kidney transplant rejection is an important risk factors for adverse graft outcome. Once diagnosed, it remains difficult to predict the risk of graft loss and the response to anti-rejection treatment. The aim of this thesis was to identify biomarkers during acute rejection, which predict the r

  12. Selective leaching studies of deep-sea sediments loaded with americium, neptunium and plutonium

    International Nuclear Information System (INIS)

    A series of selective leaching experiments were undertaken to investigate the solid phase speciation and distribution of americium, neptunium and plutonium which had been experimentally loaded onto different marine sediment types. The chemical leaches employed showed rather poor selectivity but certain trends were evident. Adsorption was not by ion exchange. Americium showed a preferential affinity for carbonate and plutonium for organic matter. Neptunium appeared to have no preferential affinities. Americium was sorbed by acetic acid residues (CaCO3 removed) and by unleached carbonate-rich sediments with equal efficiency. This indicates that it is able to diversify its solid phase affinity/distribution depending upon which solid phases are available. (author)

  13. Investigation of Copper Ammonia Leaching from Smelter Slags: Characterization, Leaching and Kinetics

    Science.gov (United States)

    Bidari, Ehsan; Aghazadeh, Valeh

    2015-10-01

    Although ammonia leaching of copper from slags has been reported generally as a part of copper slag utilization methods, but no detailed studies have been reported in the literature. In this research, we tried to investigate the effect of different parameters on ammonia leaching of copper from copper smelting slag by identifying different copper-bearing phases and following them during leaching time. Mineralogical characterization of the smelting slag (1.7 pct Cu) was done using X-ray fluorescence, X-ray diffraction, optical microscopy, diagnostic leaching tests, and scanning electron microscopy. The characterization studies indicated that main copper-bearing species are soluble copper oxides and chalcocite along with minor amount of covellite, bornite, blister copper particles, and chalcopyrite. It was also found that only approximately 0.2 pct Cu was present in the insoluble bulk silicate phases. These results suggest that approximately 88 pct of the total copper of slag could be extracted by ammonia sulfide leaching. Leaching tests were carried out and the effects of various parameters, namely pH, ammonia concentration, temperature, presence of oxygen, stirring speed, and pulp density were examined on copper leaching. The temperature and stirring speed had the most pronounced effect on the copper leaching, whereas ammonia affected the leaching yield at low concentrations of ammonia. It was found that 78 pct of Cu could be extracted within 4 hours and under optimum conditions: T = 343 K (70 °C), 2M ammonia, pH 10.5, stirring speed = 900 rpm, pulp density = 10 pct ( w s/ v). The kinetic data were analyzed with the shrinking core models, and it was found that the leaching process is controlled by both the interfacial transfer and diffusion across the product layer and the activation energy is calculated to be 49.4 kJ mol-1.

  14. Remediation of contaminated soil using heap leach mining technology

    International Nuclear Information System (INIS)

    Los Alamos National Laboratory is evaluating the systems technology for heap treatment of excavated soils to remove and treat hazardous chemical and radioactive wastes. This new technology would be an extrapolation of current heap leach mining technology. The candidate wastes for treatment are those organic or inorganic (including radioactive) compounds that will chemically, physically, or biologically react with selected reagents. The project would start with bench-scale testing, followed by pilot-scale testing, and eventually by field-scale testing. Various reagents would be tried in various combinations and sequences to obtain and optimize the desired treatment results. The field-scale testing would be preceded by site characterization, process design, and equipment selection. The final step in this project is to transfer the systems technology to the private sector, probably to the mining industry. 6 refs., 1 fig

  15. Analysis of factors affecting the effect of stope leaching

    International Nuclear Information System (INIS)

    The industrial test and industrial trial production of stope leaching were carried out at Taoshan orefield of Dabu deposit. The results of test and trial production showed obvious differences in leaching rate and leaching time. Compared with industrial trial production of stope leaching, the leaching rate of industrial test was higher, and leaching time was shorter. It was considered that the blasting method and liquid arrangement were the main factors affecting the leaching rate and leaching time according to analysis. So we put forward the following suggestions: the technique of deep hole slicing tight-face blasting was used to reduce the yield of lump ores, the effective liquid arrangement methods were adopted to make the lixiviant infiltrating throughout whole ore heap, and bacterial leaching was introduced. (authors)

  16. Reducing acid leaching of manganiferous ore: Effect of the iron removal operation on solid waste disposal

    International Nuclear Information System (INIS)

    The process of reducing acid leaching of manganiferous ore is aimed at the extraction of manganese from low grade manganese ores. This work is focused on the iron removal operation. The following items have been considered in order to investigate the effect of the main operating conditions on solid waste disposal and on the process costs: (i) type and quantity of the base agent used for iron precipitation, (ii) effective need of leaching waste separation prior to the iron removal operation, (iii) presence of a second leaching stage with the roasted ore, which might also act as a preliminary iron removal step, and (iv) effect of tailings washing on the solid waste classification. Different base compounds have been tested, including CaO, CaCO3, NaOH, and Na2CO3. The latter gave the best results concerning both the precipitation process kinetics and the reagent consumption. The filtration of the liquor leach prior to iron removal was not necessary, implying significant savings in capital costs. A reduction of chemical consumption and an increase of manganese concentration in the solution were obtained by introducing secondary leaching tests with the previously roasted ore; this additional step was introduced without a significant decrease of global manganese extraction yield. Finally, toxicity characteristic leaching procedure (TCLP) tests carried out on the leaching solid waste showed: (i) a reduction of arsenic mobility in the presence of iron precipitates, and (ii) the need for a washing step in order to produce a waste that is classifiable as not dangerous, taking into consideration the existing Environmental National Laws

  17. Leaching behaviour of bottom ash from RDF high-temperature gasification plants

    International Nuclear Information System (INIS)

    This study investigated the physical properties, the chemical composition and the leaching behaviour of two bottom ash (BA) samples from two different refuse derived fuel high-temperature gasification plants, as a function of particle size. The X-ray diffraction patterns showed that the materials contained large amounts of glass. This aspect was also confirmed by the results of availability and ANC leaching tests. Chemical composition indicated that Fe, Mn, Cu and Cr were the most abundant metals, with a slight enrichment in the finest fractions. Suitability of samples for inert waste landfilling and reuse was evaluated through the leaching test EN 12457-2. In one sample the concentration of all metals was below the limit set by law, while limits were exceeded for Cu, Cr and Ni in the other sample, where the finest fraction showed to give the main contribution to leaching of Cu and Ni. Preliminary results of physical and geotechnical characterisation indicated the suitability of vitrified BA for reuse in the field of civil engineering. The possible application of a size separation pre-treatment in order to improve the chemical characteristics of the materials was also discussed.

  18. Leaching of the potentially toxic pollutants from composites based on waste raw material

    Directory of Open Access Journals (Sweden)

    Terzić Anja

    2012-01-01

    Full Text Available The disposal of the fly ash generated in coal based power-plants may pose a significant risk to the environment due to the possible leaching of hazardous pollutants, such as toxic metals. Also, there is a risk of leaching even when fly ash is built-in the construction composites. Fly ashes from various landfills were applied in several composite samples (mortar, concrete and brick without any physical or thermal pre-treatment. The leachability of the potentially toxic pollutants from the fly ash based products was investigated. The leaching behavior and potential environmental impact of the 11 potentially hazardous elements was tracked: Pb, Cd, Zn, Cu, Ni, Cr, Hg, As, Ba, Sb and Se. A detailed study of physico-chemical characteristics of the fly ash, with accent on trace elements and the chemical composition investigation is included. Physico/chemical properties of fly ash were investigated by means of X-ray fluorescence, differential thermal analysis and X-ray diffraction methods. Scanning electron microscope was used in microstructural analysis. The results show that most of the elements are more easily leachable from the fly ash in comparison with the fly ash based composites. The leaching of investigated pollutants is within allowed range thus investigated fly ashes can be reused in construction materials production.

  19. Prediction of the P-leaching potential of arable soils in areas with high livestock densities

    Institute of Scientific and Technical Information of China (English)

    WERNER Wilfried; TRIMBORN Manfred; PIHL Uwe

    2006-01-01

    Due to long-term positive P-balances many surface soils in areas with high livestock density in Germany are oversupplied with available P, creating a potential for vertical P losses by leaching. In extensive studies to characterize the endangering of ground water to P pollution by chemical soil parameters it is shown that the available P content and the P concentration of the soil solution in the deeper soil layers, as indicators of the P-leaching potential, cannot be satisfactorily predicted from the available P content of the topsoils. The P equilibrium concentration in the soil solution directly above ground water table or the pipe drainage system highly depends on the relative saturation of the P-sorption capacity in this layer. A saturation index of <20% normally corresponds with Pequilibrium concentrations of <0.2 mg P/L. Phytoremediation may reduce the P leaching potential of P-enriched soils only over a very long period.

  20. Assessing the potential for pesticide leaching for the pine forest areas of Tenerife.

    Science.gov (United States)

    Diaz-Diaz, R; Loague, K

    2001-09-01

    Currently, no guidelines cover use of pesticides in the forested areas of the Canary island of Tenerife. An index-based model (Li) was used to rank the leaching potential of 50 pesticides that are, or could be, used for management purposes in the pine forest areas of Tenerife. Once the pesticides with the greatest leaching potential were identified, regional-scale groundwater vulnerability assessments, with consideration for data uncertainties, were generated using soil, climatic, and chemical information in a geographic information system framework for all pine forest areas of the island. Process-based simulations with the pesticide root zone model for the areas and pesticides of highest vulnerability were conducted to quantitatively characterize the leaching potentials. Carbofuran, hexazinone, picloram, tebuthiuron, and triclopyr were each identified as being potential leachers.

  1. Study of Zinc Leaching of EAF Flue Dust Using Sodium Hydroxide

    Directory of Open Access Journals (Sweden)

    Ahsan Abdul Ghani

    2016-06-01

    Full Text Available During the production of steel from Electric Arc Furnace (EAF, large amount of by-product called EAF flue dust is generated. The major proportion of flue dust is comprised of Zn (41.5 % wt.. Different phases identified by XRD analysis are zincite, franklinite and magnetite with zincite being dominant. In this study, we have performed flue dust treatment using sodium hydroxide as leaching medium. Different concentrations of alkali were used to optimize maximum recovery of Zn. XRF and Wet Chemical method were used to characterize the dust samples both before and after leaching. The optimum alkali concentration for selective leaching of zinc was found to be 4 M with a zinc recovery of 90 %.

  2. Kinetics of Reductive Acid Leaching of Cadmium-Bearing Zinc Ferrite Mixture Using Hydrazine Sulfate

    Science.gov (United States)

    Zhang, Chun; Zhang, Jianqiang; Min, Xiaobo; Wang, Mi; Zhou, Bosheng; Shen, Chen

    2015-09-01

    The reductive acid leaching kinetics of synthetic cadmium-bearing zinc ferrite was investigated, and the influence of reaction temperature, sulfuric acid and hydrazine sulfate were studied. The results illustrated that an increase in the reaction temperature, initial sulfuric acid and hydrazine sulfate significantly enhanced the extraction efficiencies of cadmium, zinc and iron. The leaching kinetics were controlled by a surface chemical reaction based on a shrinking core model. The empirical equation applied was found to fit well with the kinetics analysis; the leaching processes of cadmium, zinc and iron were similar and the activation energies were 79.9 kJ/mol, 77.9 kJ/mol and 79.7 kJ/mol, respectively. The apparent orders of cadmium-bearing zinc ferrite dissolution with respect to sulfuric acid concentration were 0.83, 0.83 and 0.84 for Cd, Zn and Fe, respectively.

  3. Plant Biomass Leaching for Nutrient Recovery in Closed Loop Systems Project

    Science.gov (United States)

    Zeitlin, Nancy P.; Wheeler, Raymond (Compiler); Lunn, Griffin

    2015-01-01

    Plants will be important for food and O2 production during long term human habitation in space. Recycling of nutrients (e.g., from waste materials) could reduce the resupply costs of fertilizers for growing these plants. Work at NASA's Kennedy Space Center has shown that ion exchange resins can extract fertilizer (plant essential nutrients) from human waste water, after which the residual brine could be treated with electrodialysis to recover more water and produce high value chemicals (e.g., acids and bases). In habitats with significant plant production, inedible biomass becomes a major source of solid waste. To "close the loop" we also need to recover useful nutrients and fertilizer from inedible biomass. We are investigating different approaches to retrieve nutrients from inedible plant biomass, including physical leaching with water, processing the biomass in bioreactors, changing the pH of leaching processing, and/or conducting multiple leaches of biomass residues.

  4. Two cases of hepatobiliary scintigraphy of liver transplantation in rejection

    Energy Technology Data Exchange (ETDEWEB)

    Kanegawa, Kimio; Nishiyama, Syouji; Muraji, Toshihiro (Kobe Children' s Hospital, Hyogo (Japan)); Ishii, Kazunari; Kouno, Michio

    1992-04-01

    We report two patients with liver transplantation who underwent hepatobiliary scintigraphy in rejection. In the first patient, hepatobiliary scintigraphy showed dilatation of bile duct but it showed good clearance from the liver. In the second patient, hepatobiliary scintigraphy showed delayed clearance from the liver. Both patients recovered from rejection. There were four main complications, including vascular and biliary abnormality, infection, and rejection, after liver transplantation. Hepatobiliary scintigraphy showed almost the same findings except for biliary complication, so it was difficult to distinguish between infection and rejection. But hepatobiliary scintigraphy may be useful to evaluate transplanted liver function in rejection. (author).

  5. Two cases of hepatobiliary scintigraphy of liver transplantation in rejection

    International Nuclear Information System (INIS)

    We report two patients with liver transplantation who underwent hepatobiliary scintigraphy in rejection. In the first patient, hepatobiliary scintigraphy showed dilatation of bile duct but it showed good clearance from the liver. In the second patient, hepatobiliary scintigraphy showed delayed clearance from the liver. Both patients recovered from rejection. There were four main complications, including vascular and biliary abnormality, infection, and rejection, after liver transplantation. Hepatobiliary scintigraphy showed almost the same findings except for biliary complication, so it was difficult to distinguish between infection and rejection. But hepatobiliary scintigraphy may be useful to evaluate transplanted liver function in rejection. (author)

  6. CURRENT VIEW ON MORPHOLOGY OF ACUTE REJECTION IN LIVER TRANSPLANTATION

    Directory of Open Access Journals (Sweden)

    L.V. Shkalova

    2012-01-01

    Full Text Available We present a scientific literature data analysis of morphological features and severity criteria of the liver allograft acute rejection during last 20 years. Modern conception was given about the role of immunological mechanisms in the de- velopment of liver graft acute rejection. We describe roles of different cell types in the destructive immune response during liver allograft acute rejection. Advantages and disadvantages of Banff-classifications 1995, 1997 are discussed as well as the necessity of grading the acute rejection as early and late. We propose clinico-morphological correlations in liver allograft acute rejection

  7. Arbuscular mycorrhizas reduce nitrogen loss via leaching.

    Directory of Open Access Journals (Sweden)

    Hamid R Asghari

    Full Text Available The capacity of mycorrhizal and non-mycorrhizal root systems to reduce nitrate (NO₃⁻ and ammonium (NH₄⁺ loss from soils via leaching was investigated in a microcosm-based study. A mycorrhiza defective tomato mutant and its mycorrhizal wildtype progenitor were used in this experiment in order to avoid the indirect effects of establishing non-mycorrhizal control treatments on soil nitrogen cycling and the wider soil biota. Mycorrhizal root systems dramatically reduced nitrate loss (almost 40 times less via leaching, compared to their non-mycorrhizal counterparts, following a pulse application of ammonium nitrate to experimental microcosms. The capacity of AM to reduce nutrient loss via leaching has received relatively little attention, but as demonstrated here, can be significant. Taken together, these data highlight the need to consider the potential benefits of AM beyond improvements in plant nutrition alone.

  8. Behavior of calcium silicate in leaching process

    Institute of Scientific and Technical Information of China (English)

    刘桂华; 李小斌; 彭志宏; 周秋生

    2003-01-01

    Based on the thermodynamic calculation, the mole ratio of CaO to SiO2, temperature and A/S of bauxitehave a profound influence on the mole ratio of 2CaO @ SiO2 to CaO @ SiO2 in sinter. CaO @ SiO2 and β-2CaO @ SiO2appear stable in caustic solution but unstable in soda solution, and CaO @ SiO2 is more stable than β-2CaO @ SiO2 un-der the same leaching condition. Compared with the conventional sinter, the rate of alumina extraction of the newsinter is large and the secondary reaction is restricted in the leaching, which might be mainly due to the more contentof CaO @ SiO2 in sinter and better stability of CaO @ SiO2 in leaching.

  9. Kinetics of Leaching Calcium from Dolomite

    Directory of Open Access Journals (Sweden)

    Azizi, A.

    2011-06-01

    Full Text Available Magnesia is obtained from magnesite ore and the production process applied should remove accompanying minerals that reduce its refractoriness. Given that magnesite reservoirs are more exploited and largely exhausted, there is a growing need for production of magnesia on the basis of other magnesium minerals. Dolomite is a promising source of magnesia because it forms large deposits, is easy to exploit, and generally contains a small quantity of impurities.The kinetics of calcium leaching from dolomite by magnesium-nitrate solution has been studied. The research program included the influence of temperature, mass fraction of magnesium nitrate in solution, dolomite particle size and leaching time. Time dependence of calcium leaching is described by relevant kinetic equations. Rate coefficients, their temperature dependence and Arrhenius activation energy have been determined.

  10. Leaching of vanadium from stone coal with sulfuric acid

    Institute of Scientific and Technical Information of China (English)

    WANG Mingyu; XIAO Liansheng; LI Qinggang; WANG Xuewen; XIANG Xiaoyan

    2009-01-01

    The effects of roasting, mass ratio of H2SO4 to stone coal, leaching temperature, liquid-to-solid ratio, grinding fineness of stone coal, and two-stage counter-current leaching on the vanadium leaching ratio were studied. The results show that the vanadium leaching ratio of roasted stone coal through two-stage counter-current leaching can reach 65.1% at the mass ratio of H2SO4 to stone coal of 20%, leaching temperature for the production of vanadium from stone coal.

  11. Chapter 3. Classical method of uranium leaching from ores and reasons for incomplete recovery at dumps of State Enterprise 'VOSTOKREDMET'. 3.3. Basic regularities of uranium ores leaching

    International Nuclear Information System (INIS)

    Present article is devoted to basic regularities of uranium ores leaching. It was found that the basic method of uranium ores enrichment and producing of reasonably rich and pure uranium concentrates (usually technical uranium oxide) is a chemical concentration concluded in selective uranium leaching from ore raw materials with further, uranium compounds - so called uranium chemical concentrates. Such reprocessing of uranium ores with the purpose of uranium chemical concentrates production, currently, are produced everywhere by hydrometallurgical methods. This method in comparison with enrichment and thermal reprocessing is a universal one. Hydrometallurgy - the part of chemical technology covering so called moist methods of metals and their compounds (in the current case, uranium) extraction from raw materials, where they are contained. It can be ores or ore concentrates produced by radiometric, gravitational, floatation enrichment, sometimes passed through high-temperature reprocessing or even industry wastes. The basic operation in hydrometallurgy is its important industrial element - metal or metals leaching as one or another compound. Leaching is conversion of one or several components to solution under impact of relevant technical solvents: water, water solutions, acids, alkali or base, solution of some salts and etc. The basic purpose of leaching in uranium technology is to obtain the most full and selective solution of uranium.

  12. Suitability of leaching test methods for fly ash and slag: A review

    Directory of Open Access Journals (Sweden)

    Manoj Kumar Tiwari

    2015-10-01

    Full Text Available Fly ash and slag leachate pollution can be of great environmental concern due to generation of these wastes in huge quantities from their respective industrial units, mainly coal-based thermal power plants and iron and steel plants. For simulation of natural leaching in laboratory, various leaching methods are available, but selection of a method that can exactly simulate the real-life scenario for accurate estimation of various pollutants is challenging; particularly, the heavy metals present and impact due to reuse or disposal of these wastes. For choosing the most suitable leaching method according to specific situation, one must primarily consider the chemical and physical properties of wastes, the composition of the source, age of waste disposal, and the climatic conditions of the disposal area. Since these factors may not be specified, a variety of leaching methods with relevant equipment have been proposed by researchers; that are based on their required information to particular conditions in absence of a prescribed protocol and non standardization of equipment. The present review is an attempt to investigate the suitable leaching method for coal fly ash and slag.

  13. [Effects of fertilization on the P accumulation and leaching in vegetable greenhouse soil].

    Science.gov (United States)

    Zhao, Ya-jie; Zhao, Mu-qiu; Lu, Cai-yan; Shi, Yi; Chen, Xin

    2015-02-01

    A packed soil column experiment was conducted to investigate the effect of different fertilization practices on phosphorus (P) accumulation and leaching potential in a vegetable greenhouse soil with different fertility levels. The results showed that the leaching loss of total P in the leachates elevated with the increment of leaching time while the accumulative leaching loss of total P was relatively low, indicating P was mainly accumulated in the soil instead of in the leachate. At the end of the leaching experiment, soil fertility and fertilization treatment affected the content of total phosphorus and Olsen-P significantly. Compared with the low-level-fertility soil, the contents of total P and Olsen-P increased by 14.3% and 12.2% in the medium-level-fertility soil, 33.3% and 37.7% in the high-level-fertility soil. Total P in the combined application of poultry manure and chemical fertilizer (M+NPK) was elevated by 5.7% and 4.3%, compared with the NPK and M treatment. Compared with NPK treatment, Olsen-P in M and M + NPK treatments augmented by 13.0% and 3.1%, respectively. Soil total P and Olsen-P mainly accumulated in the 0-10 cm and 10-20 cm soil layers, and much less in the 20-40 cm soil layer. PMID:26094462

  14. Leaching mechanisms of solidified low-level waste. The literature survey

    International Nuclear Information System (INIS)

    A literature survey on leaching mechanisms, available mathematical models and factors that affect leaching from solidified low-level radioactive waste (LLW) was compiled. Physicochemical mechanisms identified include diffusion, dissolution, ion exchange, corrosion and surface effects. Diffusion was generally considered to be the predominant mechanism in LLW leachability. However, this hierarchy of importance has been strongly questioned for waste forms containing soluble salts and has been shown to be invalid for waste forms incorporating sorbents which control the release of radionuclides by ion exchange. Leaching behavior was modeled both mathematically for curve fitting to leaching data and by consideration of physical and chemical interactions within and between solidification agents, waste materials and additives, if any. Physicochemical analyses of bitumen and polymer solidification agents have considered them to be inert encapsulants with limited water permeability. All of the mathematical models are derived from solutions to the diffusion equation. Other mechanistic processes are included as additional terms in the equation. No comprehensive evaluations of mathematical models for LLW based on curve fitting to data were found in the literature. Factors that affect leaching have been categorized as system factors, leachant factors and waste form factors. System factors include temperature, pressure, radiation, time and the ratio of waste form area to leachant volume. Leachant factors include pH, Eh, flow or replacement frequency and composition while waste form factors include composition, surface condition, porosity and surface area to volume ratio. Information from the literature is reported for each of these factors. 75 refs., 2 figs., 4 tabs

  15. Ag recovery from copper anode slime by acid leaching at atmospheric pressure to synthesize silver nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Atefeh Khaleghi; Sattar Ghader; Dariush Afzali

    2014-01-01

    In this paper, recovery of silver from anode slime of Sarcheshmeh copper complex in Iran and subsequent synthesis of silver nanoparticles from leaching solution is investigated. Sarcheshmeh anode slime is mainly consisted of Cu, Ag, Pb and Se. Amount of Ag in the considered anode slime was 5.4%(by weight). The goal was to recover as much as possible Ag from anode slime at atmospheric pressure to synthesize Ag nanoparticles. Therefore, acid leaching was used for this purpose. The anode slime was leached with sulfuric and nitric acid from room to 90 ?C at different acid concentrations and the run which yielded the most recovery of Ag was selected for Ag nanoparticles synthesis. At this condition, Cu, Pb and Se are lea-ched as well as Ag. To separate Ag from leach solution HCl was added and silver was precipitated as AgCl which were then dissolved by ammonia solution. The Ag nanoparticles are synthesized from this solution by chemical reduction method by aid of sodium borohydride in the presence of PVP and PEG as stabiliz-ers. The synthesized Ag nanoparticles showed a peak of 394 nm in UV-vis spectrum and TEM images showed a rather uniform Ag nanoparticles of 12 nm.

  16. Optimization Study on the Leaching of High Iron-Bearing Zinc Calcine After Reduction Roasting

    Science.gov (United States)

    Han, Junwei; Liu, Wei; Qin, Wenqing; Zheng, Yongxing; Luo, Honglin

    2016-02-01

    The selective leaching of zinc from high iron-bearing zinc calcine after reduction roasting was optimized by Taguchi experimental design method. The experimental parameters and their ranges were 303 to 343 K (30 to 70 °C) for leaching temperature ( T), 7 to 15 mL/g for liquid/solid ratio ( L/ S), 70 to 150 g/L for H2SO4 concentration ( C), 5 to 25 minutes for time ( t), and 100 to 500 rpm for stirring speed ( R). The results show that the optimum conditions were 303 K (30 °C), 9 mL/g, 110 g/L, 20 minutes, and 400 rpm, respectively. Under these conditions, about 92.81 pct Zn was extracted and more than 86 pct Fe was reported into the leach residue. L/ S and C had significant effects on the extractions of zinc and iron, while t and R had no significant effects, and T had significant effect on iron extraction but negligible effect on zinc extraction. This indicates that diffusion was not a major control step of the leaching process, and the dissolution of iron was controlled by chemical reaction. The interactive effects of parameters were negligible. The leach residue was mainly composed of Fe3O4 and ZnS, and its particle size was very fine.

  17. Solid State Characterizations of Long-Term Leached Cast Stone Monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Asmussen, Robert M.; Pearce, Carolyn I.; Parker, Kent E.; Miller, Brian W.; Lee, Brady D.; Buck, Edgar C.; Washton, Nancy M.; Bowden, Mark E.; Lawter, Amanda R.; McElroy, Erin M.; Serne, R Jeffrey

    2016-09-30

    This report describes the results from the solid phase characterization of six Cast Stone monoliths from the extended leach tests recently reported on (Serne et al 2016),that were selected for characterization using multiple state-of-the-art approaches. The Cast Stone samples investigated were leached for > 590 d in the EPA Method 1315 test then archived for > 390 d in their final leachate. After reporting the long term leach behavior of the monoliths, it was suggested that physical changes to the waste form samples and a depleting inventory of contaminants of potential concern may mean that effective diffusivity calculations past 63 d should not be used to t accurately represent long-term waste form behavior. Understanding the physical and chemical mechanisms that occur in the Cast Stone during the long-term leaching process is thus imperative to support long term modelling of cementitious waste form performance. These novel investigations provide an initial arsenal of techniques which can be utilized to perform such Cast Stone solid phase characterization work, which in turn can support upcoming performance assessment maintenance. The work was performed at Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions (WRPS) to characterize several properties of the long term leached Cast Stone monolith samples:

  18. USA: California rejects mandatory GMO labelling

    OpenAIRE

    Paull, John

    2012-01-01

    Buying organic remains the best strategy for US consumers to avoid eating GM food. The voters of California have rejected the proposal to label GMO food. The proposition was narrowly lost, 47% to 53% (4,326,770 ‘Yes’ votes vs. 4,884,961 ‘No’ votes). Proposition 47 was supported by the organic sector but opposed by a coalition of GMO companies and US multinational food companies. Californians were invited to vote into law ‘The California Right to Know Genetically Engineered Food Act’. Section ...

  19. [Diagnosis of rejection in a transplanted liver].

    Science.gov (United States)

    Sticová, Eva; Honsová, Eva

    2015-01-01

    Despite advances in immunosupressive therapy rejection remains the most common complication of liver transplantation in both the early and the late post-transplant period. Unlike other solid organs, liver graft rejection has some specific characteristics likely attributable to the unique immunobiologic properties and the remarkable regenerative capabilities of liver parenchyma. Acute cellular rejection is the most frequent type of the rejection episode in the liver allograft, whereas chronic (ductopenic) rejection and humoral rejection are uncommon. Since the clinical findings are not entirely characteristic, histopathological evaluation of liver biopsy remains the gold standard in the diagnosis of rejection. However, the close cooperation between the pathologist and the clinician is essential for the correct interpretation of morphologic changes.

  20. Surface modifications on InAs decrease indium and arsenic leaching under physiological conditions

    Science.gov (United States)

    Jewett, Scott A.; Yoder, Jeffrey A.; Ivanisevic, Albena

    2012-11-01

    Devices containing III-V semiconductors such as InAs are increasingly being used in the electronic industry for a variety of optoelectronic applications. Furthermore, the attractive chemical, material, electronic properties make such materials appealing for use in devices designed for biological applications, such as biosensors. However, in biological applications the leaching of toxic materials from these devices could cause harm to cells or tissue. Additionally, after disposal, toxic inorganic materials can leach from devices and buildup in the environment, causing long-term ecological harm. Therefore, the toxicity of these materials along with their stability in physiological conditions are important factors to consider. Surface modifications are one common method of stabilizing semiconductor materials in order to chemically and electronically passivate them. Such surface modifications could also prevent the leaching of toxic materials by preventing the regrowth of the unstable surface oxide layer and by creating an effective barrier between the semiconductor surface and the surrounding environment. In this study, various surface modifications on InAs are developed with the goal of decreasing the leaching of indium and arsenic. The leaching of indium and arsenic from modified substrates was assessed in physiological conditions using inductively coupled plasma mass spectrometry (ICP-MS). Substrates modified with 11-mercapto-1-undecanol (MU) and graft polymerized with poly(ethylene) glycol (PEG) were most effective at preventing indium and arsenic leaching. These surfaces were characterized using contact angle analysis, ellipsometry, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Substrates modified with collagen and synthetic polyelectrolytes were least effective, due to the destructive nature of acidic environments on InAs. The toxicity of modified and unmodified InAs, along with raw indium, arsenic, and PEG components was assessed

  1. Recycling process for recovery of gallium from GaN an e-waste of LED industry through ball milling, annealing and leaching

    International Nuclear Information System (INIS)

    Waste dust generated during manufacturing of LED contains significant amounts of gallium and indium, needs suitable treatment and can be an important resource for recovery. The LED industry waste dust contains primarily gallium as GaN. Leaching followed by purification technology is the green and clean technology. To develop treatment and recycling technology of these GaN bearing e-waste, leaching is the primary stage. In our current investigation possible process for treatment and quantitative leaching of gallium and indium from the GaN bearing e-waste or waste of LED industry dust has been developed. To recycle the waste and quantitative leaching of gallium, two different process flow sheets have been proposed. In one, process first the GaN of the waste the LED industry dust was leached at the optimum condition. Subsequently, the leach residue was mixed with Na2CO3, ball milled followed by annealing, again leached to recover gallium. In the second process, the waste LED industry dust was mixed with Na2CO3, after ball milling and annealing, followed acidic leaching. Without pretreatment, the gallium leaching was only 4.91 w/w % using 4 M HCl, 100 °C and pulp density of 20 g/L. After mechano-chemical processing, both these processes achieved 73.68 w/w % of gallium leaching at their optimum condition. The developed process can treat and recycle any e-waste containing GaN through ball milling, annealing and leaching. - Highlights: • Simplest process for treatment of GaN an LED industry waste developed. • The process developed recovers gallium from waste LED waste dust. • Thermal analysis and phase properties of GaN to Ga2O3 and GaN to NaGaO2 revealed. • Solid-state chemistry involved in this process reported. • Quantitative leaching of the GaN was achieved

  2. Alkaline leaching of metal melting industry wastes dseparation of zinc and lead in the leach solution

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this work, a thorough examinations on the extractability of zinc and lead present in the steelmaking dusts using alkaline leaching process and the effectiveness of the zinc and lead separation in the resultant leaching solutions using sulfide precipitation method were made. It was found that only about 53% of zinc and over 70% of the lead could be leached out of the dusts, while the other 47% of zinc and 306 of lead were left in the leaching residues. The zinc and lead in the resultant leaching solution can be effectively and selectively separated. When the weight ratio of sodium sulfide (M. W. = 222-240) to Pb was kept at 1.8, the lead in the solution could be precipitated out quantitatively while all the zinc was remained in the solution. The zinc left in the solution can be further recovered by the addition of extra sodium sulfide with a weight ratio of sodium sulfide to the zinc over 2.6. The resultant filtrate can be recycled to the leaching of dust in the next leaching process.

  3. Ion mobility based on column leaching of South African gold tailings dam with chemometric evaluation.

    Science.gov (United States)

    Cukrowska, Ewa M; Govender, Koovila; Viljoen, Morris

    2004-07-01

    New column leaching experiments were designed and used as an alternative rapid screening approach to element mobility assessment. In these experiments, field-moist material was treated with an extracting solution to assess the effects of acidification on element mobility in mine tailings. The main advantage of this version of column leaching experiments with partitioned segments is that they give quick information on current element mobility in conditions closely simulating field conditions to compare with common unrepresentative air-dried, sieved samples used for column leaching experiments. Layers from the tailings dump material were sampled and packed into columns. The design of columns allows extracting leachates from each layer. The extracting solutions used were natural (pH 6.8) and acidified (pH 4.2) rainwater. Metals and anions were determined in the leachates. The concentrations of metals (Ca, Mg, Fe, Mn, Al, Cr, Ni, Co, Zn, and Cu) in sample leachates were determined using ICP OES. The most important anions (NO3-, Cl-, and SO4(2)-) were determined using the closed system izotacophoresis ITP analyser. The chemical analytical data from tailings leaching and physico-chemical data from field measurements (including pH, conductivity, redox potential, temperature) were used for chemometric evaluation of element mobility. Principal factor analysis (PFA) was used to evaluate ions mobility from different layers of tailings dump arising from varied pH and redox conditions. It was found that the results from the partitioned column leaching illustrate much better complex processes of metals mobility from tailings dump than the total column. The chemometric data analysis (PFA) proofed the differences in the various layers leachability that are arising from physico-chemical processes due to chemical composition of tailings dump deposit. PMID:15109878

  4. Nitrate leaching in an Andisol treated with different types of fertilizers

    International Nuclear Information System (INIS)

    Nitrate leaching in upland fields under Japanese conditions may be reduced by substituting compost or slow-release fertilizer for readily available chemical fertilizer. - Nitrate (NO3) leaching was studied in an Andisol treated with four N fertilizers (SC: swine compost, CU: coated urea, AN: ammonium N, or NF: no fertilizer) for 7 years. Sweet corn (Zea mays L.) was grown in summer, followed by Chinese cabbage (Brassica rapa L. var. amplexicaulis) or cabbage (Brassica oleracea L. var. capitata) in autumn each year. In chemical fertilizer plots treated with AN or CU, NO3-N concentrations in soil water at 1-m depth increased markedly in the summer of the second year and fluctuated between 30 and 60 mg l-1. In the SC plot, NO3-N concentration started increasing in the fourth year, reaching the same level as in the AN and CU plots in the late period of the experiment. In the NF plot, NO3-N concentration was about 10 mg l-1 for the first 4 years and decreased to 5 mg l-1. The potential NO3-N concentrations by an N and water balance equation satisfactorily predicted NO3-N concentration in the AN and CU plots, but substantially overestimated that in the SC plot, presumably because a large portion of N from SC first accumulated in soil in the organic form. Our results indicate that, under the Japanese climate (Asian monsoon), excessive N from chemical fertilizers applied to Andisols can cause substantial NO3 leaching, while compost application is promising to establish high yields and low N leaching during a few years but would cause the same level of NO3 leaching as in chemically fertilized plots over longer periods

  5. Nitrate leaching in an Andisol treated with different types of fertilizers

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Morihiro; Zhao Bingzi; Ozaki, Yasuo; Yoneyama, Tadakatsu

    2003-03-01

    Nitrate leaching in upland fields under Japanese conditions may be reduced by substituting compost or slow-release fertilizer for readily available chemical fertilizer. - Nitrate (NO{sub 3}) leaching was studied in an Andisol treated with four N fertilizers (SC: swine compost, CU: coated urea, AN: ammonium N, or NF: no fertilizer) for 7 years. Sweet corn (Zea mays L.) was grown in summer, followed by Chinese cabbage (Brassica rapa L. var. amplexicaulis) or cabbage (Brassica oleracea L. var. capitata) in autumn each year. In chemical fertilizer plots treated with AN or CU, NO{sub 3}-N concentrations in soil water at 1-m depth increased markedly in the summer of the second year and fluctuated between 30 and 60 mg l{sup -1}. In the SC plot, NO{sub 3}-N concentration started increasing in the fourth year, reaching the same level as in the AN and CU plots in the late period of the experiment. In the NF plot, NO{sub 3}-N concentration was about 10 mg l{sup -1} for the first 4 years and decreased to 5 mg l{sup -1}. The potential NO{sub 3}-N concentrations by an N and water balance equation satisfactorily predicted NO{sub 3}-N concentration in the AN and CU plots, but substantially overestimated that in the SC plot, presumably because a large portion of N from SC first accumulated in soil in the organic form. Our results indicate that, under the Japanese climate (Asian monsoon), excessive N from chemical fertilizers applied to Andisols can cause substantial NO{sub 3} leaching, while compost application is promising to establish high yields and low N leaching during a few years but would cause the same level of NO{sub 3} leaching as in chemically fertilized plots over longer periods.

  6. Life cycle assessment and residue leaching: The importance of parameter, scenario and leaching data selection

    International Nuclear Information System (INIS)

    Highlights: • Relevance of metal leaching in waste management system LCAs was assessed. • Toxic impacts from leaching could not be disregarded. • Uncertainty of toxicity, due to background activities, determines LCA outcomes. • Parameters such as pH and L/S affect LCA results. • Data modelling consistency and coverage within an LCA are crucial. - Abstract: Residues from industrial processes and waste management systems (WMSs) have been increasingly reutilised, leading to landfilling rate reductions and the optimisation of mineral resource utilisation in society. Life cycle assessment (LCA) is a holistic methodology allowing for the analysis of systems and products and can be applied to waste management systems to identify environmental benefits and critical aspects thereof. From an LCA perspective, residue utilisation provides benefits such as avoiding the production and depletion of primary materials, but it can lead to environmental burdens, due to the potential leaching of toxic substances. In waste LCA studies where residue utilisation is included, leaching has generally been neglected. In this study, municipal solid waste incineration bottom ash (MSWI BA) was used as a case study into three LCA scenarios having different system boundaries. The importance of data quality and parameter selection in the overall LCA results was evaluated, and an innovative method to assess metal transport into the environment was applied, in order to determine emissions to the soil and water compartments for use in an LCA. It was found that toxic impacts as a result of leaching were dominant in systems including only MSWI BA utilisation, while leaching appeared negligible in larger scenarios including the entire waste system. However, leaching could not be disregarded a priori, due to large uncertainties characterising other activities in the scenario (e.g. electricity production). Based on the analysis of relevant parameters relative to leaching, and on general results

  7. Life cycle assessment and residue leaching: The importance of parameter, scenario and leaching data selection

    Energy Technology Data Exchange (ETDEWEB)

    Allegrini, E., E-mail: elia@env.dtu.dk [Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby (Denmark); Butera, S. [Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby (Denmark); Kosson, D.S. [Vanderbilt University, Department of Civil and Environmental Engineering, Box 1831 Station B, Nashville, TN 37235 (United States); Van Zomeren, A. [Energy Research Centre of the Netherlands (ECN), Department of Environmental Risk Assessment, P.O. Box 1, 1755 ZG Petten (Netherlands); Van der Sloot, H.A. [Hans van der Sloot Consultancy, Dorpsstraat 216, 1721 BV Langedijk (Netherlands); Astrup, T.F. [Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby (Denmark)

    2015-04-15

    Highlights: • Relevance of metal leaching in waste management system LCAs was assessed. • Toxic impacts from leaching could not be disregarded. • Uncertainty of toxicity, due to background activities, determines LCA outcomes. • Parameters such as pH and L/S affect LCA results. • Data modelling consistency and coverage within an LCA are crucial. - Abstract: Residues from industrial processes and waste management systems (WMSs) have been increasingly reutilised, leading to landfilling rate reductions and the optimisation of mineral resource utilisation in society. Life cycle assessment (LCA) is a holistic methodology allowing for the analysis of systems and products and can be applied to waste management systems to identify environmental benefits and critical aspects thereof. From an LCA perspective, residue utilisation provides benefits such as avoiding the production and depletion of primary materials, but it can lead to environmental burdens, due to the potential leaching of toxic substances. In waste LCA studies where residue utilisation is included, leaching has generally been neglected. In this study, municipal solid waste incineration bottom ash (MSWI BA) was used as a case study into three LCA scenarios having different system boundaries. The importance of data quality and parameter selection in the overall LCA results was evaluated, and an innovative method to assess metal transport into the environment was applied, in order to determine emissions to the soil and water compartments for use in an LCA. It was found that toxic impacts as a result of leaching were dominant in systems including only MSWI BA utilisation, while leaching appeared negligible in larger scenarios including the entire waste system. However, leaching could not be disregarded a priori, due to large uncertainties characterising other activities in the scenario (e.g. electricity production). Based on the analysis of relevant parameters relative to leaching, and on general results

  8. PEP Support: Laboratory Scale Leaching and Permeate Stability Tests

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Renee L.; Peterson, Reid A.; Rinehart, Donald E.; Buchmiller, William C.

    2010-05-21

    This report documents results from a variety of activities requested by the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The activities related to caustic leaching, oxidative leaching, permeate precipitation behavior of waste as well as chromium (Cr) leaching are: • Model Input Boehmite Leaching Tests • Pretreatment Engineering Platform (PEP) Support Leaching Tests • PEP Parallel Leaching Tests • Precipitation Study Results • Cr Caustic and Oxidative Leaching Tests. Leaching test activities using the PEP simulant provided input to a boehmite dissolution model and determined the effect of temperature on mass loss during caustic leaching, the reaction rate constant for the boehmite dissolution, and the effect of aeration in enhancing the chromium dissolution during caustic leaching. Other tests were performed in parallel with the PEP tests to support the development of scaling factors for caustic and oxidative leaching. Another study determined if precipitate formed in the wash solution after the caustic leach in the PEP. Finally, the leaching characteristics of different chromium compounds under different conditions were examined to determine the best one to use in further testing.

  9. Prediction of leaching rate in heap leaching process by grey dynamic model GDM(1,1)

    Institute of Scientific and Technical Information of China (English)

    LIU Jin-zhi; wu Ai-xiang

    2008-01-01

    The method of developing GM(1,1)model is extended on the basis of grey system theory.Conditions for the transfer function that improve smoothness of original data sequence and decrease the revert error are given.The grey dynamic model is first combined with the transfer function to predict the leaching rate in heap leaching process.The resuhs show that high prediction accuracy call be expected by using the proposed method.This provides a new approach to realize prediction and control of the future behavior of leaching kinetics.

  10. Coal fly ash interaction with environmental fluids: Geochemical and strontium isotope results from combined column and batch leaching experiments

    International Nuclear Information System (INIS)

    Highlights: ► Element release during fly ash extraction experiments controlled by mineralogy. ► Strontium isotopes in fly ash are not homogenized during coal combustion. ► Element correlations with 87Sr/86Sr indicate chemically resistant silicate phase. ► Sr isotopes can uniquely identify fly ash fluids leaking into the environment. - Abstract: The major element and Sr isotope systematics and geochemistry of coal fly ash and its interactions with environmental waters were investigated using laboratory flow-through column leaching experiments (sodium carbonate, acetic acid, nitric acid) and sequential batch leaching experiments (water, acetic acid, hydrochloric acid). Column leaching of Class F fly ash samples shows rapid release of most major elements early in the leaching procedure, suggesting an association of these elements with soluble and surface bound phases. Delayed release of certain elements (e.g., Al, Fe, Si) signals gradual dissolution of more resistant silicate or glass phases as leaching continues. Strontium isotope results from both column and batch leaching experiments show a marked increase in 87Sr/86Sr ratio with continued leaching, yielding a total range of values from 0.7107 to 0.7138. For comparison, the isotopic composition of fluid output from a fly ash impoundment in West Virginia falls in a narrow range around 0.7124. The experimental data suggest the presence of a more resistant, highly radiogenic silicate phase that survives the combustion process and is leached after the more soluble minerals are removed. Strontium isotopic homogenization of minerals in coal does not always occur during the combustion process, despite the high temperatures encountered in the boiler. Early-released Sr tends to be isotopically uniform; thus the Sr isotopic composition of fly ash could be distinguishable from other sources and is a useful tool for quantifying the possible contribution of fly ash leaching to the total dissolved load in natural surface

  11. Uremic escape of renal allograft rejection

    Energy Technology Data Exchange (ETDEWEB)

    van Schilfgaarde, R. (Rijksuniversiteit Leiden (Netherlands). Academisch Ziekenhuis); van Breda Vriesman, P.J.C. (Rijksuniversiteit Limburg Maastricht (Netherlands). Dept. of Immunopathology)

    1981-10-01

    It is demonstrated in rats that, in the presence of early postoperative severe but transient uremia, the survival of first set Brown-Norway (BN) renal allografts in Lewis (LEW) recipients is at least three times prolonged when compared to non-uremic controls. This phenomenon is called 'uremic escape of renal allograft rejection'. By means of lethal X-irradiation of donors of BN kidneys transplanted into transiently uremic and non-uremic LEW recipients, the presence of passenger lymphocyte immunocompetence is demonstrated to be obilgatory for this phenomenon to occur. As a result of mobile passenger lymphocyte immunocompetence, a graft-versus-host (GVH) reaction is elicited in the spleens of LEW recipients of BN kidneys which amplifies the host response. The splenomegaly observed in LEW recipients of BN kidneys is caused not only by this GVH reaction, which is shown to be exquisitely sensitive to even mild uremia. It is also contributed to by a proliferative response of the host against the graft (which latter response is equated with an in vivo equivalent of a unilateral mixed lymphocyte reaction (MLR)), since the reduction in spleen weights caused by abrogation of mobile passenger lymphocyte immunocompetence brought about by lethal donor X-irradiation is increased significantly by early postoperative severe but transient uremia. It is concluded that in uremic escape of renal allograft rejection both reactions are suppressed by uremia during the early post-operative period.

  12. Spent LWR fuel leach tests: Waste Isolation Safety Assessment program

    International Nuclear Information System (INIS)

    Spent light-water-reactor (LWR) fuels with burnups of 54.5, 28 and 9 MWd/kgU were leach-tested in deionized water at 250C. Fuel burnup has no apparent effect on the calculated leach rates based upon the behavior of 137Cs and 239+240Pu. A leach test of 54.5 MWd/kgU spent fuel in synthetic sea brine showed that the cesium-based leach rate is lower in sea brine than in deionized water. A rise in the leach rate was observed after approximately 600 d of cumulative leaching. During the rise, the leach rate for all the measured radionuclides become nearly equal. Evidence suggests that exposure of new surfaces to the leachant may cause the increase. As a result, experimental work to study leaching mechanisms of spent fuel has been initiated. 22 figures

  13. Leaching of Main Elements of Glass Immersed in Beishan Groundwater

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>The leaching quantities of the elements from the HLW are very important parameters for the safety assessments of the repository of high level radioactive wastes. It is necessary to study the leaching

  14. Leaching of Plastic Additives to Marine Organisms

    NARCIS (Netherlands)

    Koelmans, A.A.; Besseling, E.; Foekema, E.M.

    2014-01-01

    It is often assumed that ingestion of microplastics by aquatic species leads to increased exposure to plastic additives. However, experimental data or model based evidence is lacking. Here we assess the potential of leaching of nonylphenol (NP) and bisphenol A (BPA) in the intestinal tracts of Areni

  15. Heap leaching of clay ish uranium ores

    International Nuclear Information System (INIS)

    This paper describes an experimental facility, built near El Lobo mine. In it we study the beneficiation of low-grade uranium ore. The mineral has a great amount of clay and fines. The flow-sheet used has four steps: head leaching, ph-ajustement, ion-exchange and participation. We show, also, the most interesting results. (Author)

  16. The role of CD8+ T cells during allograft rejection

    Directory of Open Access Journals (Sweden)

    Bueno V.

    2002-01-01

    Full Text Available Organ transplantation can be considered as replacement therapy for patients with end-stage organ failure. The percent of one-year allograft survival has increased due, among other factors, to a better understanding of the rejection process and new immunosuppressive drugs. Immunosuppressive therapy used in transplantation prevents activation and proliferation of alloreactive T lymphocytes, although not fully preventing chronic rejection. Recognition by recipient T cells of alloantigens expressed by donor tissues initiates immune destruction of allogeneic transplants. However, there is controversy concerning the relative contribution of CD4+ and CD8+ T cells to allograft rejection. Some animal models indicate that there is an absolute requirement for CD4+ T cells in allogeneic rejection, whereas in others CD4-depleted mice reject certain types of allografts. Moreover, there is evidence that CD8+ T cells are more resistant to immunotherapy and tolerance induction protocols. An intense focal infiltration of mainly CD8+CTLA4+ T lymphocytes during kidney rejection has been described in patients. This suggests that CD8+ T cells could escape from immunosuppression and participate in the rejection process. Our group is primarily interested in the immune mechanisms involved in allograft rejection. Thus, we believe that a better understanding of the role of CD8+ T cells in allograft rejection could indicate new targets for immunotherapy in transplantation. Therefore, the objective of the present review was to focus on the role of the CD8+ T cell population in the rejection of allogeneic tissue.

  17. Mineralogy and uranium leaching of ores from Triassic Peribaltic sandstones

    OpenAIRE

    Gajda, Dorota; Kiegiel, Katarzyna; Zakrzewska-Koltuniewicz, Grazyna; Chajduk, Ewelina; Bartosiewicz, Iwona; Wolkowicz, Stanislaw

    2014-01-01

    The recovery of uranium and other valuable metals from Polish Peribaltic sandstones were examined. The solid–liquid extraction is the first stage of the technology of uranium production and it is crucial for the next stages of processing. In the laboratory experiments uranium was leached with efficiencies 71–100 % by acidic lixiviants. Satisfactory results were obtained for the alkaline leaching process. Almost 100 % of uranium was leached with alkaline carbonate solution. In post leaching so...

  18. Enhancements of LEACH Algorithm for Wireless Networks: A Review

    Directory of Open Access Journals (Sweden)

    M. Madheswaran

    2013-12-01

    Full Text Available Low Energy Adaptive Clustering Hierarchy (LEACH protocol is the first hierarchical cluster based routing protocol successfully used in the Wireless Sensor Networks (WSN. In this paper, various enhancements used in the original LEACH protocol are examined. The basic operations, advantages and limitations of the modified LEACH algorithms are compared to identify the research issues to be solved and to give the suggestions for the future proposed routing algorithms of wireless networks based on LEACH routing algorithm.

  19. Treatment of metallurgical wastes : recovery of metal values from smelter slags by pressure oxidative leaching

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.; Perederiy, I.; Papangelakis, V.G. [Toronto Univ., ON (Canada). Dept. of Chemical Engineering and Applied Chemistry

    2008-07-01

    Vast quantities of slag are produced and dumped as waste by-products during the production of base metals by smelting operations. These slags contain large amounts of valuable metals which lead to a decrease in metal yield and, combined with the entrapped sulphur, pose a danger to the environment. The dissolution of fayalite is important for the selective recovery of valuable metals and the cleanup of slags in high pressure oxidative leaching. The nature of base metals and iron in solidified slag must be investigated in order to understand the mechanism of the process. This paper discussed the application of powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM) for the characterization of a smelter slag microstructure. The study used leaching tests with the same smelter slag to measure and monitor the results of leaching, including metal extraction levels, the extent of iron dissolution as well as impurity contents. The paper provided information on the experiment with particular reference to slag leaching, chemical analysis, and characterization. It was concluded that slag consists of several solid phases with base metal sulfide and oxide droplets entrapped in the fayalite matrix or silica regions. Therefore, nickel, copper, cobalt, and zinc need to be exposed either chemically or mechanically to promote their recovery. 21 refs., 4 tabs., 5 figs.

  20. Physical mechanisms of plant roots affecting weathering and leaching of loess soil

    Institute of Scientific and Technical Information of China (English)

    LI Yong; ZHANG Qingwen; WAN Guojiang; HUANG Ronggui; PIAO Hechun; BAI Lingyu; LI Lu

    2006-01-01

    Plant roots have potential impacts on soil mineral weathering and leaching. Our objective is to understand the physical mechanisms of plant roots affecting weathering and leaching of loess soil. Root densities were measured through the method of a large-size dug profile, and transport fluxes of soil elements were determined using an undisturbed monolith soil infiltration device on the hilly and gully regions of the Chinese Loess Plateau. The results show that the improvement effects of soil environment by plant roots are mainly controlled by the density and weight of the fibrous roots with the diameters less than 1 mm. Plant roots have the stronger effects on soil physical properties than chemical properties. The principal components analysis (PCA) indicates that soil physical properties by plant roots account for 56.7% of variations in soil environment whereas soil chemical properties and pH contribute about 24.2% of the soil variations. The roles of plant roots in controlling soil weathering and leaching increased in the following order: infiltration enhancement > increase of bioactive substance > stabilization of soil structure. The effects of plant roots on soil mineral weathering and leaching can be quantified using the multiple regression models with the high prediction accuracies developed in this study.

  1. Pesticide leaching through sandy and loamy fields - long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme.

    Science.gov (United States)

    Rosenbom, Annette E; Olsen, Preben; Plauborg, Finn; Grant, Ruth; Juhler, René K; Brüsch, Walter; Kjær, Jeanne

    2015-06-01

    The European Union authorization procedure for pesticides includes an assessment of the leaching risk posed by pesticides and their degradation products (DP) with the aim of avoiding any unacceptable influence on groundwater. Twelve-year's results of the Danish Pesticide Leaching Assessment Programme reveal shortcomings to the procedure by having assessed leaching into groundwater of 43 pesticides applied in accordance with current regulations on agricultural fields, and 47 of their DP. Three types of leaching scenario were not fully captured by the procedure: long-term leaching of DP of pesticides applied on potato crops cultivated in sand, leaching of strongly sorbing pesticides after autumn application on loam, and leaching of various pesticides and their DP following early summer application on loam. Rapid preferential transport that bypasses the retardation of the plow layer primarily in autumn, but also during early summer, seems to dominate leaching in a number of those scenarios. PMID:25771345

  2. The Rejection-Rage Contingency in Borderline Personality Disorder

    Science.gov (United States)

    Berenson, Kathy R.; Downey, Geraldine; Rafaeli, Eshkol; Coifman, Karin; Leventhal, Nina

    2011-01-01

    Though longstanding clinical observation reflected in the DSM-IV suggests that the rage characteristic of borderline personality disorder (BPD) often appears in response to perceived rejection, the role of perceived rejection in triggering rage in BPD has never been empirically tested. Extending basic personality research on rejection sensitivity to a clinical sample, a priming-pronunciation experiment and a 21-day experience-sampling diary examined the contingent relationship between perceived rejection and rage in participants diagnosed with BPD compared to healthy controls. Despite the differences in these two assessment methods, the indices of rejection-contingent rage that they produced were both elevated in the BPD group, and were strongly interrelated. They provide corroborating evidence that reactions to perceived rejection significantly explain the rage seen in BPD. PMID:21500875

  3. Multivisceral transplantation in pigs: a clinicopathological analysis of tissue rejection.

    Directory of Open Access Journals (Sweden)

    Mitsuoka,Shintaro

    1995-10-01

    Full Text Available In this study, we established the surgical procedure and postoperative care of multivisceral transplantation (MVTX in pigs, and examined the functional changes and rejection pattern of transplanted organs in MVTX. Twenty-two MVTXs were performed without immunosuppression, and nine cases (41% that survived for 5 days or more after MVTX were used for evaluation. Rejection in grafts including the liver, pancreas, and gastrointestinal tract were assessed histopathologically. On day 5 after transplantation, the duodenum and small bowel already showed signs of mild rejection. On the other hand, in the liver, pancreas and stomach, rejection occurred later and was still mild on day 16. Hepatic rejection in MVTX appeared to occur later than in simple liver transplantation (LTX. These results showed that the susceptibility to rejection of individual visceral organs varies.

  4. MDMA DECREASES THE EFFECTS OF SIMULATED SOCIAL REJECTION

    OpenAIRE

    Frye, Charles G.; Wardle, Margaret C; Norman, Greg J.; de Wit, Harriet

    2013-01-01

    3-4-methylenedioxymethamphetamine (MDMA) increases self-reported positive social feelings and decreases the ability to detect social threat in faces, but its effects on experiences of social acceptance and rejection have not been determined. We examined how an acute dose of MDMA affects subjective and autonomic responses to simulated social acceptance and rejection. We predicted that MDMA would decrease subjective responses to rejection. On an exploratory basis, we also examined the effect of...

  5. Regulatory Allospecific T Cell Clones Abrogate Chronic Allograft Rejection

    OpenAIRE

    Waaga-Gasser, Ana Maria; Grimm, Martin R.; Lutz, Jens; Lange, Volkmar; Lenhard, Susanne M.; Aviles, Beatriz; Kist-van Holthe, Joana E; Lebedeva, Tatiana; Samsonov, Dimitry; Meyer, Detlef; Hancock, Wayne W.; Heemann, Uwe; Gasser, Martin; Chandraker, Anil

    2009-01-01

    True alloantigen-specific tolerance is the ultimate goal of solid organ transplantation, eliminating the need for long-term immunosuppression. Recent evidence suggests that Th1-derived cytokines are associated with rejection and Th2-derived cytokines with long-term allograft survival, but the roles of these subsets in rejection and tolerance are incompletely understood. Here, we analyzed the functional and regulatory capacities of T cell clones derived from tolerant and rejecting rats (Wistar...

  6. Rejection of Organic Micropollutants by Clean and Fouled Nanofiltration Membranes

    OpenAIRE

    Lifang Zhu

    2015-01-01

    The rejection of organic micropollutants, including three polycyclic aromatic hydrocarbons (PAHs) and three phthalic acid esters (PAEs), by clean and fouled nanofiltration membranes was investigated in the present study. The rejection of organic micropollutants by clean NF90 membranes varied from 87.9 to more than 99.9%, while that of NF270 membranes ranged from 32.1 to 92.3%. Clear time-dependence was observed for the rejection of hydrophobic micropollutants, which was attributed to the adso...

  7. The private rejection of unfair offers and emotional commitment

    OpenAIRE

    Yamagishi, Toshio; Horita, Yutaka; Takagishi, Haruto; Shinada, Mizuho; Tanida, Shigehito; Cook, Karen S.

    2009-01-01

    In a series of experiments, we demonstrate that certain players of an economic game reject unfair offers even when this behavior increases rather than decreases inequity. A substantial proportion (30–40%, compared with 60–70% in the standard ultimatum game) of those who responded rejected unfair offers even when rejection reduced only their own earnings to 0, while not affecting the earnings of the person who proposed the unfair split (in an impunity game). Furthermore, even when the responde...

  8. Comparison of percolation to batch and sequential leaching tests: theory and data.

    Science.gov (United States)

    Grathwohl, Peter; Susset, Bernd

    2009-10-01

    Leaching tests are becoming more relevant in assessing solid waste material, particularly with respect to groundwater risks. In the field, water infiltration is the dominant leaching mechanism, which is simulated in the lab with batch and column tests. In this study, we compared percolation, through analytical solutions of the advection-dispersion equation, to laboratory batch and sequential leaching tests. The analytical solutions are supported with comprehensive data from various field and laboratory leaching of different solutes from waste materials and soils collected in long-term joint research projects funded by the German Federal Ministry for Education and Research and the Federal Environment Agency. The comparison of theory and data is facilitated if concentrations and cumulative release are plotted versus the liquid-solid ratios (LS). Both theory and data indicate that leaching behaviour is independent of duration and physical dimensions of the leaching tests. This holds even if field lysimeters are compared to laboratory columns of different size, different flow velocities as well as different contact times. In general, laboratory batch tests over predict effluent concentrations (for LSsulphate from demolition waste) in column and lysimeter tests compares very well and agrees with the analytical solutions. Overall, reproducibility and agreement with theory of column tests are better than batch tests, presumably because the latter are prone to artefacts (e.g. in liquid-solid separation steps). Theory and data fit surprisingly well, despite the fact that the theory is based on the local equilibrium assumption; non-linear sorption and chemical reactions in the solid waste materials are not considered.

  9. Recovery of iron from cyanide tailings with reduction roasting-water leaching followed by magnetic separation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yali; Li, Huaimei [College of Chemical Engineering, Shandong University of Technology, 255081, Zibo, Shandong (China); Yu, Xianjin, E-mail: xjy@sdut.edu.cn [College of Chemical Engineering, Shandong University of Technology, 255081, Zibo, Shandong (China)

    2012-04-30

    Highlights: Black-Right-Pointing-Pointer Using reduction roasting-water leaching-magnetic separation method, the recovery of iron from cyanide tailings was optimized. Black-Right-Pointing-Pointer The recovery of iron was highly depended on the water-leaching process after reduction roasting. Black-Right-Pointing-Pointer The results suggest that the method can be effectively used for iron recovery, and the grade of magnetic concentrate and recovery rate can reach 59.11% and 75.12%, respectively. - Abstract: Cyanide tailing is a kind of solid waste produced in the process of gold extraction from gold ore. In this paper, recovery of iron from cyanide tailings was studied with reduction roasting-water leaching process followed by magnetic separation. After analysis of chemical composition and crystalline phase, the effects of different parameters on recovery of iron were chiefly introduced. Systematic studies indicate that the high recovery rate and grade of magnetic concentrate of iron can be achieved under the following conditions: weight ratios of cyanide tailings/activated carbon/sodium carbonate/sodium sulfate, 100:10:3:10; temperature, 50 Degree-Sign C; time, 60 min at the reduction roasting stage; the liquid to solid ratio is 15:1 (ml/g), leaching at 60 Degree-Sign C for 5 min and stirring speed at 20 r/min at water-leaching; exciting current is 2 A at magnetic separation. The iron grade of magnetic concentrate was 59.11% and the recovery ratio was 75.12%. The mineralography of cyanide tailings, roasted product, water-leached sample, magnetic concentrate and magnetic tailings were studied by X-ray powder diffraction (XRD) technique. The microstructures of above products except magnetic tailings were also analyzed by scanning electron microscope (SEM) and energy disperse spectroscopy (EDS) to help understand the mechanism.

  10. Influence of container base material (Fe) on SIMFUEL leaching behaviour

    International Nuclear Information System (INIS)

    The chemical stability of spent fuel will be greatly influenced by the redox potential of the near field. Presence of reductants such as iron is likely to be an important factor to maintain the original integrity of spent fuel. In this work experimental data about the influence of metallic iron (container base material) on SIMFUEL leaching behavior under simulated granite and saline repository conditions is presented. In the presence of iron uranium concentration undergoes a sharp decrease. This is much more noticeable in the experiments performed under initial oxic conditions. The effect of iron on simulated fission products of SIMFUEL is very important for the elements with high redox sensitivity such as molybdenum. On the contrary, strontium remains stable during the entire tests and it seems not be affected by changes in redox potential. Copyright (2001) Material Research Society

  11. Community rejection following sexual assault as ‘forced migration’

    OpenAIRE

    AJ Morgen

    2013-01-01

    When women are banished from their communities following sexual assault, this rejection should be considered an act of forced migration by the administrators of truth commission reparations programmes.

  12. Cytomegalovirus and chronic allograft rejection in liver transplantation

    Institute of Scientific and Technical Information of China (English)

    Liang-Hui Gao; Shu-Sen Zheng

    2004-01-01

    Cytomegalovirus (CMV) remains one of the most frequent viral infections and the most common cause of death after liver transplantation (LT). Chronic allograft liver rejection remains the major obstacle to long-term allograft survival and CMV infection is one of the suggested risk factors for chronic allograft rejection. The precise relationship between cytomegalovirus and chronic rejection remains uncertain.This review addresses the morbidity of cytomegalovirus infection and the risk factors associated with it, the relationship between cytomegalovirus and chronic allograft liver rejection and the potential mechanisms of it.

  13. Activation of Rejected Fly Ash Using Flue Gas Desulphurization (FGD) Sludge

    Institute of Scientific and Technical Information of China (English)

    QIAO Xiu-chen; POON Chisun; LIN Zong-shou

    2003-01-01

    Low-grade fly ash ( rejected fly ash, rFA ), a significant portion of the pulverized fuel ash ( PFA ) produced from coal-fired power plauts and rejected from the ash classifying process, remains unused due to its high carbon content and large particle size ( > 45μm ). But it is thonght that the rejected ash may have potential uses in chemical stabilization/solidification ( S/S ) processes which need relatively lower strengths and a lower chemical reactivity. Flue Gas Desulphurisation ( FGD ) sludge is a by-product of air pollution control equipment in coal fired power plants whose chemical composition is mainly gypsum. As there is no effective usage of both of these two ntaterials , it is of interest to research on the possible octtivation of rFA using FGD . This paper presents experimental results of a study on the properties of rFA activated by the FGD in rFA-cement pastes. Different percetages of FGD were added into the mix to study the effects of the FGD on the reaction of the rFA blended cement pastes.The results show that FGD takes effect as an activator only at late curing ages. Adding Ca ( OH)2 enhances the effect of FGD on activating the hytration of rFA. Also, 10% FGD by weight of rFA is the optimal addition in the rFA-cement pastes. The results of the compressive strength measurements correlate well with the porosity results.

  14. Leaching of metals from steel samples in peracetic acid

    Science.gov (United States)

    Yabutani, Tomoki; Nakamura, Takamasa; Takayabagi, Toshio

    2015-03-01

    In this paper, leaching behavior of metallic species from steel samples in peracetic acid was investigated. We compared the leaching efficiency between peracetic acid and acetic acid to estimate the role of peroxo functional group for the leaching. As a result, peracetic acid enhanced the leaching ability of metallic species from the high speed steel and the alloy steel samples. MoO3, Mo, MO2C, W, WO3, VC and MnO2 were effectively leached by peracetic acid, while the stainless steel had a high resistance against corrosion by peracetic acid.

  15. Physic-chemical evaluation of leach and water from the Borba Gato streamlet within the catchment area of the urban waste landfill of Maringá, Paraná State, Brazil=Avaliação físico-química do lixiviado e da água do ribeirão Borba Gato na área de influência do aterro de resíduos de Maringá, Estado do Paraná, Brasil

    Directory of Open Access Journals (Sweden)

    Carlos de Barros Júnior

    2012-01-01

    Full Text Available The physic-chemical characteristics of leach deposited in the landfill waste pond and of water from the Borba Gato streamlet are evaluated. Twenty-six physic-chemical parameters were analyzed from three collection sites, or rather, two in the streamlet, one upstream (P-01 and one downstream (P-02 of the landfill waste pond, and one in the leach deposit pond (P-03. The streamlet area under analysis was impacted due to being in an agricultural area and for its urban waste deposits. Parameter concentrations of aluminum, iron and mercury were reported above the quality standard of freshwater, according to Conama 357/2005 resolution (class 2. Further, throughout the rainy period, the ammoniac nitrogen content was above the resolution quality standard for fresh water. Moreover, landfill leach was above standards of effluent discharge established by Conama 357/2005. An efficient treatment for the effluent generated in Maringá is required since there is evidence of leach pollution of the Borba Gato streamlet.Este estudo teve como objetivo avaliar as características físico-químicas do lixiviado depositado na lagoa do aterro e da água do ribeirão Borba Gato. Foram analisados 26 parâmetros físico-químicos de três pontos de coletas, dois no ribeirão, a montante (P-01 e a jusante (P-02 do aterro de resíduos, e um na lagoa de depósito de percolado do aterro (P-03. A área do ribeirão estudada se apresentou impactada, por ser uma região agrícola e pela deposição dos resíduos de Maringá. Dentre os parâmetros estudados, registrou-se que, na maioria dos meses, concentrações de alumínio, ferro e mercúrio estavam acima do padrão de qualidade de água doce da resolução do Conama 357/2005 (Classe 2. Além disso, verificou-se que no período chuvoso, P-02 registrou teores de nitrogênio amoniacal acima do padrão de qualidade de água doce da resolução, assim como o lixiviado do aterro apresentou-se acima do padrão do lançamento de

  16. Mechanochemical leaching of chalcopyrite concentrate by sulfuric acid

    Institute of Scientific and Technical Information of China (English)

    Sina Hejazi; Jalil Vahdati khaki; Abolfazl Babakhani

    2016-01-01

    This study aimed to introduce a new cost-effective methodology for increasing the leaching efficiency of chalcopyrite concentrates at ambient temperature and pressure. Mechanical activation was employed during the leaching (mechanochemical leaching) of chalcopyrite concentrates in a sulfuric acid medium at room temperature and atmospheric pressure. High energy ball milling process was used during the leaching to provide the mechanochemical leaching condition, and atomic absorption spectroscopy and cyclic voltammetry were used to de-termine the leaching behavior of chalcopyrite. Moreover, X-ray diffraction and scanning electron microscopy were used to characterize the chalcopyrite powder before and after leaching. The results demonstrated that mechanochemical leaching was effective; the extraction of copper increased significantly and continuously. Although the leaching efficiency of chalcopyrite was very low at ambient temperature, the percentages of copper dissolved in the presence of hydrogen peroxide (H2O2) and ferric sulfate (Fe2(SO4)3) after 20 h of mechanochemical leaching reached 28%and 33%, respectively. Given the efficiency of the developed method and the facts that it does not require the use of an autoclave and can be conducted at room temperature and atmospheric pressure, it represents an economical and easy-to-use method for the leaching industry.

  17. Evaluation of glass leaching as nutrient source for microalgae growth; Evaluacion del comportamiento de vidrios lixiviados como nutrientes de algas

    Energy Technology Data Exchange (ETDEWEB)

    Grabska, N.; Tamayo, A.; Mazo, M. A.; Pascual, L.; Rubio, J.

    2015-10-01

    Three glasses with an elemental composition similar to the nutrient ratio required for Spirulina platensis growth and with different SiO{sub 2} content have been prepared. The glasses were crushed and sieved into 2 different fractions and the effect of the particle size has been studied in terms of the leaching kinetics of each element. The chemical analysis of the leaching water was used for obtaining the dissolution rate curves for each element taking part of the glass composition. From the calculation of the leaching rate constant and the exponential constant of the lixiviation reaction, it has been evaluated the Spirulina platensis growth in ambient normal conditions of light, temperature and pH of the growing media. It has been concluded that, either from the modification of the chemical composition of the glass or its particle size, it is possible to tune the delivery of the nutrients to match the growth rate of Spirulina platensis. (Author)

  18. Leaching of Electronic Waste Using Biometabolised Acids

    Institute of Scientific and Technical Information of China (English)

    M. Saidan; B. Brown; M. Valix

    2012-01-01

    The revolution in information and communication technology has brought huge technical benefits and wealth, but has created a major global problem: the generation of vast amounts of electronic waste, or e-waste through product obsolesce. The challenge in managing e-waste will be in developing sustainable recycling tech- nologies that are able to address the volume and complexity of this waste using cost effective and ecologically sen-sitive methods. In this study, the capability or microorganism metabolic acids in dissolving the metallic tractions from waste printed circuit boards was examined. Several factors were considered in the examination of the activityof the acids-including secondary reactions, solution pH, temperature and the nature of ligands in solutions (or bioacid constituents). The leaching tests were cgnducted ex-situ, using synthetic organic acids. Leaching was performed for periods of up to 6 hat 70-90 ℃ and 1000 r-min-1.

  19. Lead sulphate leaching by sodium chloride solution

    Directory of Open Access Journals (Sweden)

    Conić Vesna T.

    2013-01-01

    Full Text Available Bioleaching treatment of complex multi-metallic Cu-Zn-Pb-Ag-Au mineral concentrates leds to the formation, besides easily soluble zinc and cooper sulphates, of hardly soluble lead (II sulfate (PbSO4 sludge. To determine the leaching parameters of PbSO4 with NaCl in the bioleaching residue, lead sulphate solution was synthetically prepared. The effect of process parameters, namely NaCl concentration, solid:liquid phase ratio, processing time, temperature and Cl ions was examined. It was found that 100% Pb by leaching can be achieved with NaCl concentration of 250 g/dm3, time 20 min, temperature 353 K and solid:liquid phase ratio =1:20.

  20. The equilibrium leach testing of CAGR hulls

    International Nuclear Information System (INIS)

    Equilibrium leach tests were carried out on a laboratory scale in order to investigate the long-term performance of an intermediate level waste repository. The tests involved leaching fully active Commercial Advanced Gas-cooled Reactor (CAGR) hulls in the presence of crushed matrix and backfill materials. The matrix materials used were blast furnace slag (BFS)/ordinary Portland cement (OPC) and epoxide MS7531/MS7532, and the backfill materials were bentonite and pulverised fuel ash/ordinary Portland cement (PFA/OPC). Comparison of the long-lived radionuclide concentrations with the derived drinking water levels indicates that the performance of a repository under oxidising conditions would tend to be limited by the release of I-129 and Tc-99. (author)

  1. Leaching from denture base materials in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Lygre, H.; Solheim, E.; Gjerdet, N.R. [School of Medicine, Univ. of Bergen (Norway)

    1995-04-01

    Specimens made from denture base materials were leached in Ringer Solution and in ethanol. The specimens comprised a heat-cured product processed in two different ways and two cold-cured materials. The organic compounds leaching from the specimens to the solutions were separated, identified, and quantified by a combined gas-chromatography and gas-chromatography/mass-spectrometry technique. Additives and degradation products, possibly made by free radical reactions, were released from the denture base materials. In Ringer solution only phthalates could be quantified. In ethanol solvent, biphenyl, dibutyl phthalate, dicyclohexyl phthalate, phenyl benzoate, and phenyl salicylate were quantified. In addition, copper was found in the ethanol solvent from one of the denture base materials. The amount of leachable organic compounds varies among different materials. Processing temperature influences the initial amount of leachable compounds. 36 refs., 7 figs., 1 tab.

  2. Corneal allograft rejection: Risk factors, diagnosis, prevention, and treatment

    Directory of Open Access Journals (Sweden)

    Dua Harminder

    1999-01-01

    Full Text Available Recent advances in corneal graft technology, including donor tissue retrieval, storage and surgical techniques, have greatly improved the clinical outcome of corneal grafts. Despite these advances, immune mediated corneal graft rejection remains the single most important cause of corneal graft failure. Several host factors have been identified as conferring a "high risk" status to the host. These include: more than two quadrant vascularisation, with associated lymphatics, which augment the afferent and efferent arc of the immune response; herpes simplex keratitis; uveitis; silicone oil keratopathy; previous failed (rejected grafts; "hot eyes"; young recipient age; and multiple surgical procedures at the time of grafting. Large grafts, by virtue of being closer to the host limbus, with its complement of vessels and antigen-presenting Langerhans cells, also are more susceptible to rejection. The diagnosis of graft rejection is entirely clinical and in its early stages the clinical signs could be subtle. Graft rejection is largely mediated by the major histocompatibility antigens, minor antigens and perhaps blood group ABO antigens and some cornea-specific antigens. Just as rejection is mediated by active immune mediated events, the lack of rejection (tolerance is also sustained by active immune regulatory mechanisms. The anterior chamber associated immune deviation (ACAID and probably, conjunctiva associated lymphoid tissue (CALT induced mucosal tolerance, besides others, play an important role. Although graft rejection can lead to graft failure, most rejections can be readily controlled if appropriate management is commenced at the proper time. Topical steroids are the mainstay of graft rejection management. In the high-risk situations however, systemic steroids, and other immunosuppressive drugs such as cyclosporin and tacrolimus (FK506 are of proven benefit, both for treatment and prevention of rejection.

  3. Alkaline leaching of iron and steelmaking dust

    OpenAIRE

    Stafanova, Anna; Aromaa, Jari

    2012-01-01

    Steel production generates significant quantities of dust and sludge in blast furnaces (BF),basic oxygen furnaces (BOF), and electric arc furnaces (EAF). These dusts contain toxicelements, such as heavy metals, and are thus classified as harmful waste making the disposalof them expensive. In addition, direct recycling of dust back to steel production is hindered dueto the presence of zinc. In this literature survey the alkaline leaching of zinc from iron and steelmaking dusts isreviewed. T...

  4. Long-term leaching mechanisms of ashes and slags; combining laboratory experiments with computer simulations

    International Nuclear Information System (INIS)

    The leaching properties of slags and ashes have been studied on four waste materials: municipal solid waste incineration, MSWI, bottom ash, wood ash, electric arc furnace slag and blast furnace slag. The aim of the study has been to investigate properties that influence the long-term leaching of these materials. The results of the laboratory experiments have been used in computer simulations using CHEMFRONTS. CHEMFRONTS is a coupled geochemical and transport computer program developed by the author within this work. The main variable influencing the leaching of metal from solid waste is the final pH of the solution. This can be controlled by several factors, but if the contact time between the water and the waste material is sufficient, the waste itself often controls the pH by buffering reactions. The buffering capacity of a material is, therefore, one of the most important factors to investigate when the long-term leaching behaviour is to be predicted. A pH titration curve has been made for each material within this work, using a pH batch experimental series. The change in pH with time has also been studied. The materials have been studied by X-ray diffraction analysis and Scanning Electron Microscopy / Energy Dispersive Spectroscopy to assess the mineralogy and morphology of the materials. The mineralogy is important for computer simulations. A number of leaching experiments have been performed. A batch flow-through method has been developed which is a serial batch experiment, in which the contact time can be controlled. This technique makes it possible to have oxygen access in all the columns, to simulate partly saturated conditions. Sampling is also possible in the columns. The influence of particle size has been studied, and surprisingly no influence of the particle size could be noted after 24 hours of leaching. The substitution of sand in concrete with steel slag has been studied by both physical and chemical tests. The steel slag concrete had physical

  5. Long-term leaching mechanisms of ashes and slags; Combining laboratory experiments with computer simulations

    Energy Technology Data Exchange (ETDEWEB)

    Baeverman, C.

    1997-12-31

    The leaching properties of slags and ashes have been studied on four waste materials: municipal solid waste incineration, MSWI, bottom ash, wood ash, electric arc furnace slag and blast furnace slag. The aim of the study has been to investigate properties that influence the long-term leaching of these materials. The results of the laboratory experiments have been used in computer simulations using CHEMFRONTS. CHEMFRONTS is a coupled geochemical and transport computer program developed by the author within this work. The main variable influencing the leaching of metal from solid waste is the final pH of the solution. This can be controlled by several factors, but if the contact time between the water and the waste material is sufficient, the waste itself often controls the pH by buffering reactions. The buffering capacity of a material is, therefore, one of the most important factors to investigate when the long-term leaching behaviour is to be predicted. A pH titration curve has been made for each material within this work, using a pH batch experimental series. The change in pH with time has also been studied. The materials have been studied by X-ray diffraction analysis and Scanning Electron Microscopy / Energy Dispersive Spectroscopy to assess the mineralogy and morphology of the materials. The mineralogy is important for computer simulations. A number of leaching experiments have been performed. A batch flow-through method has been developed which is a serial batch experiment, in which the contact time can be controlled. This technique makes it possible to have oxygen access in all the {sup c}olumns{sup ,} to simulate partly saturated conditions. Sampling is also possible in the {sup c}olumns{sup .} The influence of particle size has been studied, and surprisingly no influence of the particle size could be noted after 24 hours of leaching. The substitution of sand in concrete with steel slag has been studied by both physical and chemical tests. The steel slag

  6. CHARACTERIZATION OF TANK 16H ANNULUS SAMPLES PART II: LEACHING RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    Hay, M.; Reboul, S.

    2012-06-19

    The closure of Tank 16H will require removal of material from the annulus of the tank. Samples from Tank 16H annulus were characterized and tested to provide information to evaluate various alternatives for removing the annulus waste. The analysis found all four annulus samples to be composed mainly of Si, Na, and Al and lesser amounts of other elements. The XRD data indicate quartz (SiO{sub 2}) and sodium aluminum nitrate silicate hydrate (Na{sub 8}(Al{sub 6}Si{sub 6}O{sub 24})(NO{sub 3}){sub 2}.4H{sub 2}O) as the predominant crystalline mineral phases in the samples. The XRD data also indicate the presence of crystalline sodium nitrate (NaNO{sub 3}), sodium nitrite (NaNO{sub 2}), gibbsite (Al(OH){sub 3}), hydrated sodium bicarbonate (Na{sub 3}H(CO{sub 3}){sub 2}.2H{sub 2}O), and muscovite (KAl{sub 2}(AlSi{sub 3}O{sub 10})(OH){sub 2}). Based on the weight of solids remaining at the end of the test, the water leaching test results indicate 20-35% of the solids dissolved after three contacts with an approximately 3:1 volume of water at 45 C. The chemical analysis of the leachates and the XRD results of the remaining solids indicate sodium salts of nitrate, nitrite, sulfate, and possibly carbonate/bicarbonate make up the majority of the dissolved material. The majority of these salts were dissolved in the first water contact and simply diluted with each subsequent water contact. The water leaching removed large amounts of the uranium in two of the samples and approximately 1/3 of the {sup 99}Tc from all four samples. Most of the other radionuclides analyzed showed low solubility in the water leaching test. The oxalic acid leaching test result indicate approximately 34-47% of the solids in the four annulus samples will dissolve after three contacts with an approximately 3:1 volume of acid to solids at 45 C. The same sodium salts found in the water leaching test comprise the majority of dissolved material in the oxalic acid leaching test. However, the oxalic acid was

  7. Economic leaching at Roessing Uranium Limited

    International Nuclear Information System (INIS)

    In the fourteen years that Roessing Uranium Limited has been in production, the metallurgical operations and controls on the leaching plant have envolved through four basic stages. Initially, the emphasis was placed on the achievement of consistent plant operation by overcoming severe start-up difficulties. The second stage involved the attainment of the design operating targets and also the commissioning of the ferric-leaching reactors in order to achieve a ferric ion concentration of more than 3.0 g/l. Improvements in control then became the priority, with the emphasis on consistently achieving the target concentrations of ferric ions, total iron, and terminal acidity. The latest phase has concentrated on the optimization of costs by means of adjustments to the historically established operating parameters in order to achieve large savings on consumables while maintaining the leaching efficiencies. Apart from the obvious incentive of reducing costs in an inflationary economy and a depressed uranium market, impetus for this work was given by a change in the type of ore from the open pit, which has the effect of reducing the extraction efficiency while increasing the consumption of consumable materials. These problems and their solutions are discussed in detail, and the importance to cost-effective optimization of an accurate up-to-date cost-reporting structure is stressed. 9 figs., 2 tabs

  8. CVLEACH: Coverage based energy efficient LEACH algorithm

    Directory of Open Access Journals (Sweden)

    Ankit Thakkar

    2012-06-01

    Full Text Available Designing a protocol stack for wireless sensor network (WSNis a challenging task due to energy, computational and storageconstraints. Energy spent for communication between sensornodes dominates the energy spent for the computation [10].Multi-hop short range communication between wireless sensorsnodes is energy efficient compared to single-hop long rangecommunication. Hierarchical clustering is one of the possiblesolutions to save energy of wireless sensor nodes. Low-EnergyAdaptive Clustering Hierarchy (LEACH, Centralized Low-Energy Adaptive Clustering Hierarchy (LEACH-C andAdvanced Low-Energy Adaptive Clustering Hierarchy(ALEACH are energy efficient hierarchical clustering routingprotocol. In this paper we proposed Coverage based Low-EnergyAdaptive Clustering Hierarchy routing protocol – CVLEACH tomake uniform distribution of Cluster Heads (CHs by creatingnon-overlapped cluster regions using overhearing properties ofthe sensor nodes, which makes the routing protocol more energyefficient and prolongs life time of a wireless sensor network.Simulation results show that CVLEACH improves network lifetime compared to LEACH and ALEACH algorithms.

  9. Pesticide leaching through sandy and loamy fields – Long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme

    International Nuclear Information System (INIS)

    The European Union authorization procedure for pesticides includes an assessment of the leaching risk posed by pesticides and their degradation products (DP) with the aim of avoiding any unacceptable influence on groundwater. Twelve-year's results of the Danish Pesticide Leaching Assessment Programme reveal shortcomings to the procedure by having assessed leaching into groundwater of 43 pesticides applied in accordance with current regulations on agricultural fields, and 47 of their DP. Three types of leaching scenario were not fully captured by the procedure: long-term leaching of DP of pesticides applied on potato crops cultivated in sand, leaching of strongly sorbing pesticides after autumn application on loam, and leaching of various pesticides and their DP following early summer application on loam. Rapid preferential transport that bypasses the retardation of the plow layer primarily in autumn, but also during early summer, seems to dominate leaching in a number of those scenarios. - Highlights: • Field-results reveal shortcomings in the EU authorization procedure for pesticides. • The plough layer can be bypassed via preferential transport in e.g. wormholes. • Pesticides properties are decisive for leaching pattern on the sandy fields. • The hydrogeological settings control the leaching patterns on the loamy fields. • Pesticide detection frequency seems to be independent of the month of the year. - Long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme reveals shortcomings in the European Union authorization procedure for pesticides

  10. Characterization, Washing, Leaching, and Filtration of C-104 Sludge

    Energy Technology Data Exchange (ETDEWEB)

    KP Brooks; PR Bredt; GR Golcar; SA Hartley; LK Jagoda; KG Rappe; MW Urie

    2000-06-09

    continuously adding approximately 5 L of 0.01-M NaOH and then removing it through the filter as permeate. The purpose of this washing step with 0.01-MNaOH was to remove water-soluble components that might inhibit dissolution of salts during caustic leaching, while avoiding peptization of the solids that occurs at a pH below 12. After washing the sludge with dilute caustic, it was combined with 3-M caustic, and the slurry was leached in a stainless steel vessel at 85 C for 8 hours. This leaching was followed by two 0.01-M caustic washes, each conducted in a stainless steel vessel to dilute remaining analytes from the interstitial liquids. Each rinse was performed at 85 C for 8 hours. Permeate from each of these process steps was removed using the crossflow filter system. Samples of the permeate from each slurry-washing activity and all intermediate process steps were taken and analyzed for chemical and radiochemical constituents. The fraction of each component removed was calculated. Key results are presented in Table S.1.

  11. Characterization, Washing, Leaching, and Filtration of C-104 Sludge

    International Nuclear Information System (INIS)

    approximately 5 L of 0.01-M NaOH and then removing it through the filter as permeate. The purpose of this washing step with 0.01-MNaOH was to remove water-soluble components that might inhibit dissolution of salts during caustic leaching, while avoiding peptization of the solids that occurs at a pH below 12. After washing the sludge with dilute caustic, it was combined with 3-M caustic, and the slurry was leached in a stainless steel vessel at 85 C for 8 hours. This leaching was followed by two 0.01-M caustic washes, each conducted in a stainless steel vessel to dilute remaining analytes from the interstitial liquids. Each rinse was performed at 85 C for 8 hours. Permeate from each of these process steps was removed using the crossflow filter system. Samples of the permeate from each slurry-washing activity and all intermediate process steps were taken and analyzed for chemical and radiochemical constituents. The fraction of each component removed was calculated. Key results are presented in Table S.1

  12. Mechanical Activation-Assisted Reductive Leaching of Cadmium from Zinc Neutral Leaching Residue Using Sulfur Dioxide

    Science.gov (United States)

    Zhang, Chun; Min, Xiaobo; Chai, Liyuan; Zhang, Jianqiang; Wang, Mi

    2015-12-01

    In this work, zinc neutral leaching residue was mechanically activated by ball-milling. The subsequent leaching behavior and kinetics of cadmium extraction in a mixed SO2-H2SO4 system were studied. Changes in the crystalline phase, lattice distortion, particle size and morphology, which were induced by mechanical activation, were also investigated. The activated samples showed different physicochemical characteristics, and cadmium extraction was found to be easier than for the un-activated samples. Under the same conditions, mechanical activation contributed to higher cadmium leaching. The cadmium extraction kinetics at 75-95°C was found to fit the shrinking core model. The raw neutral leaching residue, and the samples activated for 60 min and 120 min had a calculated activation energy of 65.02 kJ/mol, 59.45 kJ/mol and 53.46 kJ/mol, respectively. The leaching residue was characterized by ICP, XRD and SEM analysis. According to XRD analysis, the main phases in the residue were lead sulfate (PbSO4), zinc sulfide (ZnS) and cadmium sulfide (CdS).

  13. Process optimization and kinetics for leaching of rare earth metals from the spent Ni-metal hydride batteries.

    Science.gov (United States)

    Meshram, Pratima; Pandey, B D; Mankhand, T R

    2016-05-01

    Nickel-metal hydride batteries (Ni-MH) contain not only the base metals, but valuable rare earth metals (REMs) viz. La, Sm, Nd, Pr and Ce as well. In view of the importance of resource recycling and assured supply of the contained metals in such wastes, the present study has focussed on the leaching of the rare earth metals from the spent Ni-MH batteries. The conditions for the leaching of REMs from the spent batteries were optimized as: 2M H2SO4, 348K temperature and 120min of time at a pulp density (PD) of 100g/L. Under this condition, the leaching of 98.1% Nd, 98.4% Sm, 95.5% Pr and 89.4% Ce was achieved. Besides the rare earth metals, more than 90% of base metals (Ni, Co, Mn and Zn) were also leached out in this condition. Kinetic data for the dissolution of all the rare earth metals showed the best fit to the chemical control shrinking core model. The leaching of metals followed the mechanism involving the chemical reaction proceeding on the surface of particles by the lixiviant, which was corroborated by the XRD phase analysis and SEM-EDS studies. The activation energy of 7.6, 6.3, 11.3 and 13.5kJ/mol was acquired for the leaching of neodymium, samarium, praseodymium and cerium, respectively in the temperature range 305-348K. From the leach liquor, the mixed rare earth metals were precipitated at pH∼1.8 and the precipitated REMs was analyzed by XRD and SEM studies to determine the phases and the morphological features. PMID:26746588

  14. Leaching behaviour and ecotoxicity evaluation of chars from the pyrolysis of forestry biomass and polymeric materials

    OpenAIRE

    Bernardo, Maria S.; Mendes, S.; Lapa, N.; Gonçalves, Margarida; Mendes, Benilde; Pinto, Filomena; Lopes, M. Helena

    2014-01-01

    The main objective of this study was to assess the environmental risk of chars derived from the pyrolysis of mixtures of pine, plastics, and scrap tires, by studying their leaching potential and ecotoxicity. Relationships between chemical composition and ecotoxicity were established to identify contaminants responsible for toxicity. Since metallic contaminants were the focus of the present study, an EDTA washing step was applied to the chars to selectively remove metals that can be responsibl...

  15. 25 CFR 163.18 - Acceptance and rejection of bids.

    Science.gov (United States)

    2010-04-01

    ... bids; or (2) Acceptance of the offer of another bidder who, at bid opening, makes written request that... 25 Indians 1 2010-04-01 2010-04-01 false Acceptance and rejection of bids. 163.18 Section 163.18... Forest Management and Operations § 163.18 Acceptance and rejection of bids. (a) The high bid received...

  16. Graft rejection after hematopoietic cell transplantation with nonmyeloablative conditioning

    DEFF Research Database (Denmark)

    Masmas, T.N.; Petersen, S.L.; Madsen, H.O.;

    2008-01-01

    -dose fludarabine and total body irradiation (TBI). The association of pretransplantation risk factors with rejection and the effect of chimerism and graft-versus-host disease on rejection were analyzed. Overall survival (OS) and progression free survival (PFS) were compared between patients with and without...

  17. Heterosexual Rejection and Mate Choice: A Sociometer Perspective

    Directory of Open Access Journals (Sweden)

    Lin eZHANG

    2015-12-01

    Full Text Available Previous studies about the effects of social rejection on individuals’ social behaviors have produced mixed results and tend to study mating behaviors from a static point of view. However, mate selection in essence is a dynamic process, and therefore sociometer theory opens up a new perspective for studying mating and its underlying practices. Based on this theory and using self-perceived mate value in the relationship between heterosexual rejection and mate choice as a mediating role, this current study examined the effects of heterosexual rejection on mate choice in two experiments. Results showed that heterosexual rejection significantly reduced self-perceived mate value, expectation, and behavioral tendencies, while heterosexual acceptance indistinctively increased these measures. Self-perceived mate value did not serve as a mediator in the relationship between heterosexual rejection and mate expectation, but it mediated the relationship between heterosexual rejection and mating behavior tendencies towards potential objects. Moreover, individuals evaded both rejection and irrelevant people when suffering from rejection.

  18. 48 CFR 1419.505 - Rejecting Small Business Administration recommendations.

    Science.gov (United States)

    2010-10-01

    ... Rejecting Small Business Administration recommendations. (a) A written justification in support of the CO's... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Rejecting Small Business Administration recommendations. 1419.505 Section 1419.505 Federal Acquisition Regulations System DEPARTMENT...

  19. 48 CFR 19.505 - Rejecting Small Business Administration recommendations.

    Science.gov (United States)

    2010-10-01

    ... Small Business Administration recommendations. (a) If the contracting officer rejects a recommendation... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Rejecting Small Business Administration recommendations. 19.505 Section 19.505 Federal Acquisition Regulations System FEDERAL...

  20. 48 CFR 219.505 - Rejecting Small Business Administration recommendations.

    Science.gov (United States)

    2010-10-01

    ...-Asides for Small Business 219.505 Rejecting Small Business Administration recommendations. (b) The... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Rejecting Small Business Administration recommendations. 219.505 Section 219.505 Federal Acquisition Regulations System...

  1. 48 CFR 2919.505 - Rejecting Small Business Administration recommendations.

    Science.gov (United States)

    2010-10-01

    ... Small Business 2919.505 Rejecting Small Business Administration recommendations. When the SBA... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Rejecting Small Business Administration recommendations. 2919.505 Section 2919.505 Federal Acquisition Regulations System DEPARTMENT...

  2. 48 CFR 14.404-2 - Rejection of individual bids.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Rejection of individual... of individual bids. (a) Any bid that fails to conform to the essential requirements of the invitation... total price of the bid, but the prices for individual line items as well. (g) Any bid may be rejected...

  3. 48 CFR 814.404-2 - Rejection of individual bids.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Rejection of individual... Rejection of individual bids. (a) When a contracting officer finds a bid that is being considered for an... nonresponsive an individual bid that is not in compliance with the Government's bid acceptance time,...

  4. Chronic allograft rejection: A significant hurdle to transplant success

    Directory of Open Access Journals (Sweden)

    Malgorzata Kloc

    2014-01-01

    Full Text Available The state-of-the-art immunosuppression drugs do not ensure indefinite transplant survival, and most transplants are continuously lost to chronic rejection even years posttransplantation. This form of rejection is responsible for long-term failure of transplanted organs. The mechanisms involved in development of chronic rejection are not well-understood. One of the main features of chronic rejection is progressive luminal narrowing of graft vessels, which results in compromised blood flow, ischemia, cell death, and finally graft failure. All the existing immunosuppressive regimens are targeting acute rejection, and at present there is no available therapy for prevention of chronic rejection. Chronic rejection involves two major, but interrelated responses: The first is the host immune response against the transplant mediated primarily by alloreactive T and B cells, and the second is injury and repair of the graft (vasculopathy of graft vessels. Here we focus on recent advances in understanding the cellular and molecular aspects of chronic transplant vasculopathy and function of macrophages, topics pivotal for development of novel antichronic rejection therapies.

  5. Family Rejection Triples Risk for Suicide Attempts by Transgender People

    Science.gov (United States)

    ... contact with their child; there were incidents of domestic violence; children cut off communication; or parents or siblings stopped communicating with the person. In the case of "high" level rejection, the ... study found. A high level of family rejection was tied to a two and a ...

  6. Subclinical Rejection in Renal Transplantation: Reappraised.

    Science.gov (United States)

    Mehta, Rajil; Sood, Puneet; Hariharan, Sundaram

    2016-08-01

    Short-term outcomes in renal transplantation have improved significantly in the past few years. However, the improvement in long-term outcomes has been modest. The reasons for graft failure beyond the first year of transplantation have been attributed to several different factors. We believe that subclinical rejection (SCR) may be 1 of the factors that contribute to graft loss in the long run. We also believe that there are data to suggest that SCR leads to progressive fibrosis and loss of graft function. This has been demonstrated even in patients who have mild degrees of subclinical inflammation. This review outlines the major studies that have been published on this important topic. It also outlines potential risk factors for the development of SCR. The current approach and diagnostic methods are discussed as well as their pros and cons. Newer noninvasive methods of diagnosis as well as molecular diagnostics and their merits and shortcomings are also discussed in some depth. Thus, the proposed state of the art review on SCR will create a renewed interest at all levels including transplant clinicians, transplant researchers, pharmaceutical industries as well as regulatory organizations. PMID:26985747

  7. Alpha Background Rejection in Bolometer Detectors

    Science.gov (United States)

    Deporzio, Nicholas; Cuore Collaboration

    This study presents the modification of bolometer detectors used in particle searches to veto or otherwise reject alpha radiation background and the statistical advantages of doing so. Several techniques are presented in detail - plastic film scintillator vetoes, metallic film ionization vetoes, and Cherenkov radiation vetoes. Plastic scintillator films are cooled to bolometer temperatures and bombarded with 1.4MeV to 6.0MeV alpha particles representative of documented detector background. Quantum dot based liquid scintillator is similarly bombarded to produce a background induced scintillation light. Photomultipliers detect this scintillation light and produce a veto signal. Layered metallic films of a primary metal, dielectric, and secondary metal, such as gold-polyethylene-gold films, are cooled to milli-kelvin temperatures and biased to produce a current signal veto when incident 1.4MeV to 6.0MeV alpha particles ionize conduction paths through the film. Calibration of veto signal to background energy is presented. These findings are extrapolated to quantify the statistical impact of such modifications to bolometer searches. Effects of these techniques on experiment duration and signal-background ratio are discussed.

  8. Solar gains and thermal rejects by ventilation

    International Nuclear Information System (INIS)

    Data recorded between September 1983 and February 1985 were analyzed in detail and the main results are as follows: • Solar radiation covers a large fraction of the daily heat load : in local climatic conditions, between October and June, solar energy provided for nearly 40 % of the heat load of the greenhouse. This amount represents 32 % of the incident radiation. • Thermal excesses that were ventilated during overheating periods (Tint > 24 °C) represent 37 % of the incident solar energy. However, due to the seasonal phase differences between the thermal need and the incident solar power, only half of these rejects could potentially be saved by a short term storage system. • A method was developed for determining the monthy net auxiliary consumption of the greenhouse. Solar gains were evaluated by means of a monthly utilization factor (ratio of the solar energy used divided by the absorbed solar energy in the greenhouse). This factor has been experimentally fitted to a function of the gain load ratio (ratio of absorbed solar energy divided by the daytime heat load). The above representation appears to be valid for any type of climate or greenhouse. • The model also takes into account the effect of wind and radiative heat losses to the sky and calculates the net auxiliary requirements within less than 10%. (author)

  9. Acute Rejection after Human Renal Transplantation

    Directory of Open Access Journals (Sweden)

    Ana Roussoulières

    2007-01-01

    Full Text Available Genes involved in acute rejection (AR after organ transplantation remain to be further elucidated. In a previous work we have demonstrated the under-expression of VE-Cadherin by endothelial cells (EC in AR following murine and human heart transplantation. Serial sections from 15 human kidney Banff-graded transplant biopsies were examined for the presence of VE-Cadherin and CD34 staining by immunohistochemistry (no AR (n=5, AR grade IA (n=5, or AR grade IIA (n=5. Quantification of peritubular EC staining were evaluated and results were expressed by the percentage of stained cells per surface analysed. There was no difference in CD34 staining between the 3 groups. VE-Cadherin expression was significantly reduced in AR Grade IIA when compared to no AR (P=.01 and to AR grade IA (P=.02. This study demonstrates a reduced VE-Cadherin expression by EC in AR after renal transplantation. The down-regulation of VE-Cadherin may strongly participate in human AR.

  10. Background Assay and Rejection in DRIFT

    CERN Document Server

    Brack, Jeff; Dorofeev, Alexei; Ezeribe, Anthony; Gauvreau, Jean-Luc; Gold, Michael; Harton, John; Lafler, Randy; Lauer, Robert; Lee, Eric R; Loomba, Dinesh; Matthews, John; Miller, Eric H; Monte, Alissa; Murphy, Alex; Paling, Sean; Phan, Nguyen; Sadler, Steve; Scarff, Andrew; Snowden-Ifft, Daniel; Spooner, Neil; Telfer, Sam; Walker, Daniel; Williams, Matt; Yuriev, Leonid

    2014-01-01

    The DRIFT-IId dark matter detector is a m$^3$-scale low-pressure TPC with directional sensitivity to WIMP-induced nuclear recoils. Its primary backgrounds were due to alpha decays from contamination on the central cathode. Efforts to reduce these backgrounds led to replacing the 20 \\mu m wire central cathode with one constructed from 0.9 \\mu m aluminized mylar, which is almost totally transparent to alpha particles. Detailed modeling of the nature and origin of the remaining backgrounds led to an in-situ, ppt-sensitive assay of alpha decay backgrounds from the central cathode. This led to further improvements in the thin-film cathode resulting in over 2 orders of magnitude reduction in backgrounds compared to the wire cathode. Finally, the addition of O$_2$ to CS$_2$ gas was found to produce multiple species of electronegative charge carriers, providing a method to determine the absolute position of nuclear recoils and reject all known remaining backgrounds while retaining a high efficiency for nuclear recoil...

  11. Effects of Sodium Citrate on the Ammonium Sulfate Recycled Leaching of Low-Grade Zinc Oxide Ores

    Science.gov (United States)

    Yang, Kun; Li, Shi-wei; Zhang, Li-bo; Peng, Jin-hui; Ma, Ai-yuan; Wang, Bao-bao

    2016-03-01

    The effects of sodium citrate on ammonium sulfate recycled leaching of low-grade zinc oxide ores were studied. By applying various kinds of detection and analysis techniques such as chemical composition analysis, chemical phase method, scanning electron microscopy and energy dispersive spectrum (SEM/EDS), X-ray diffraction (XRD) and Fourier-transforming infrared spectrum (FT-IR), zinc raw ore, its leaching slag and the functional mechanism of sodium citrate were investigated. Based on a comprehensive analysis, it can be concluded that in contrast to hemimorphite (Zn4Si2O7(OH)2 · H2O), amorphous smithsonite (ZnCO3) and zinc silicate (Zn2SiO4) prove to be refractory phases under ammonium sulfate leaching, while sodium citrate has a better chelating action with the refractory phases, resulting in a higher zinc leaching rate. Under conditions of [NH3]/[NH3]T molar ratio being 0.5, [NH3]T being 7.5 mol/L, [Na3C6H5O7] being 0.2 mol/L, S/L ratio being 1:5, temperature being 303 K, holding time being 1 h in each of the two stages, and stirring rate being 300 rpm, the leaching rate of zinc reached 93.4%. In this article, sulfate ammonium recycled technology also reveals its unique advantage in processing low-grade zinc oxide ores accompanied by high silicon and high alkaline gangue.

  12. Weatherability and Leach Resistance of Wood Impregnated with Nano-Zinc Oxide

    Directory of Open Access Journals (Sweden)

    Nami Kartal S

    2010-01-01

    Full Text Available Abstract Southern pine specimens vacuum-treated with nano-zinc oxide (nano-ZnO dispersions were evaluated for leach resistance and UV protection. Virtually, no leaching occurred in any of the nano-ZnO–treated specimens in a laboratory leach test, even at the highest retention of 13 kg/m3. However, specimens treated with high concentrations of nano-ZnO showed 58–65% chemical depletion after 12 months of outdoor exposure. Protection from UV damage after 12 months exposure is visibly obvious on both exposed and unexposed surfaces compared to untreated controls. Graying was markedly diminished, although checking occurred in all specimens. Nano-zinc oxide treatment at a concentration of 2.5% or greater provided substantial resistance to water absorption following 12 months of outdoor exposure compared to untreated and unweathered southern pine. We conclude that nano-zinc oxide can be utilized in new wood preservative formulations to impart resistance to leaching, water absorption and UV damage of wood.

  13. Best Management Practices for Minimizing Nitrate Leaching from Container-Grown Nurseries

    Directory of Open Access Journals (Sweden)

    Jianjun Chen

    2001-01-01

    Full Text Available Containerized plant production represents an extremely intensive agricultural practice; 40,000 to 300,000 containers may occupy one acre of surface area to which a large amount of chemical fertilizer is applied. Currently, recommended fertilizer application rates for the production of containerized nursery ornamental plants are in excess of plant requirements, and up to 50% of the applied fertilizers may run off or be leached from containers. Among the nutrients leached or allowed to runoff, nitrogen (N is the most abundant and is of major concern as the source of ground and surface water pollution. In this report, current N fertilizer application rates for different container-grown nursery ornamental plants, the amount of nitrate leaching or runoff from containers, and the potential for nitrate contamination of ground and surface water are discussed. In contrast, our best N management practices include: (1 applying fertilizers based on plant species need; (2 improving potting medium�s nutrient holding capacity using obscure mineral additives; (3 using controlled-release fertilizers; and (4 implementing zero runoff irrigation or fertigation delivery systems that significantly reduce nitrate leaching or runoff in containerized plant production and encourage dramatic changes in N management.

  14. Leaching and heating process as alternative to produce fish protein powder from Kilka (Clupeonella cultiventris caspia

    Directory of Open Access Journals (Sweden)

    KAVEH RAHMANIFARAH

    2014-05-01

    Full Text Available Rahmanifarah K, Shabanpour B, Shaviklo AR, Aalami M. 2014. Leaching and heating process as alternative to produce fish protein powder from Kilka (Clupeonella cultiventris caspia. Nusantara Bioscience 6: 1-6. The effect of protein extraction procedures (leached mince and heated suspension on selected properties of fish protein powder (proximate composition, pH, color, density, viscosity, fat adsorption, emulsifying capacity, emulsifying stability, foaming capacity, foaming stability, WBC, protein solubility in water, hygroscopicity, Trichloroacetic acid (TCA-soluble peptides and free sulfhydryl groups was investigated. Results showed that Fish protein powder (FPP produced by leaching mince (LM have higher protein, moisture, ash, pH, L*, viscosity, emulsion capacity, emulsion stability, foam capacity, foam stability, water binding capacity (WBC, protein solubility, hygroscopicity, TCA soluble peptides and free sulfhydryl group content than heated suspension (HS (P0.05. Overall, it was observed that high temperature during heating of suspension in HS method makes possible protein denaturation and aggregation. Consequently, based on functional, chemical and physical properties, extraction of fish protein by leaching process was found to be suitable for the production of fish protein powder.

  15. Kinetics of the leaching of TiO2 from Ti-bearing blast furnace slag

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-hua; GAI Guo-sheng; YANG Yu-fen; SUI Zhi-tong; LI Li; FU Jian-xia

    2008-01-01

    Ti-bearing blast furnace slag is a valuable secondary resource containing about 24 percent of TiO2. In this paper a process of leaching Ti-bearing blast furnace slag with sulfuric acid to recover TiO2, and the kinetics of that reaction, are described. Under laboratory conditions the rate is controlled by a chemical reaction. The leaching reaction is in accord with a shrinking un-reacted-core model. The apparent reaction order of the leaching reaction was 1.222 and the apparent activation energy was 87.01 kJ/mol. The model fits the observed data well until 90% of the TiO2 has be leached from the particles. The model disagrees with observations during later periods of the reaction because the solution becomes supersaturated with Ti ions, which precipitate as H2TiO4. The assumptions of constant reactant concentration and that there is no effect from the product layer on diffusion, also cause the model to deviate from the actual values.

  16. Nitrogen leaching from short-rotation willow coppice after intensive irrigation with wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Dimitriou, Ioannis; Aronsson, Paer [Swedish Univ. of Agricultural Sciences, Dept. of Short Rotation Forestry, Uppsala (Sweden)

    2004-05-01

    Short-rotation willow coppice is being used in several locations in Sweden as vegetation filters for wastewater treatment. An experiment was conducted in order to quantity the leaching of nitrogen and the toxic effects on the plants after application of wastewater under 'worst case' conditions. Eight 1200-l lysimeters (4 with clay and 4 with sand) were irrigated-fertilised with wastewater from dewatering of sewage sludge or with liquid fertiliser during 8 days, resulting in doses corresponding to 320 kg N ha{sup -1}. Thereafter, plants were daily irrigated with tapwater at a rate of 10 mm d{sup -1} for 123 days. Nitrate-N leaching loads from May until October were approximately 70 kg N ha{sup -1} for clay and 90 kg N ha{sup -1} for sand lysimeters (not significantly different). Leaching loads of ammonium-N and organic N were low (approximately 10 kg N ha{sup -1} for all treatments). The high nitrate-N leaching loads were mainly attributed to the high nitrogen application rate and not to the chemical composition of the fertilisers. No short-term damages to the plants caused by the application of wastewater were observed. (Author)

  17. Solar dynamic heat rejection technology. Task 1: System concept development

    Science.gov (United States)

    Gustafson, Eric; Carlson, Albert W.

    1987-01-01

    The results are presented of a concept development study of heat rejection systems for Space Station solar dynamic power systems. The heat rejection concepts are based on recent developments in high thermal transport capacity heat pipe radiators. The thermal performance and weights of each of the heat rejection subsystems is addressed in detail, and critical technologies which require development tests and evaluation for successful demonstration are assessed and identified. Baseline and several alternate heat rejection system configurations and optimum designs are developed for both Brayton and Rankine cycles. The thermal performance, mass properties, assembly requirements, reliability, maintenance requirements and life cycle cost are determined for each configuration. A specific design was then selected for each configuration which represents an optimum design for that configuration. The final recommendations of heat rejection system configuration for either the Brayton or Rankine cycles depend on the priorities established for the evaluation criteria.

  18. DYNAMIC RE-CLUSTERING LEACH-BASED (DR-LEACH PROTOCOL FOR WIRELESS SENSOR NETWORKS

    Directory of Open Access Journals (Sweden)

    Abdallah Ijjeh

    2015-11-01

    Full Text Available A Wireless Sensor Network (WSN contains a large number of sensor nodes equipped with limited energy supplies. In most applications, sensor nodes are deployed in a random fashion. Therefore, battery replacement or charging is considered not practical. As a result, routing protocols must be energy-efficient to prolong the network’s lifetime. In this paper, we propose a new Dynamic Re-clustering LEACH-Based protocol (DR-LEACH which aims to reduce the energy consumption and extending the network’s lifetime. The idea is to balance energy consumption of Cluster Heads (CHs by generating clusters with almost equal number of nodes during each round of the network life time. To perform this, we first calculate the optimal number of CHs in each round, and based on that we calculate the optimal size of each cluster. Results show that the proposed protocol improves network lifetime and reduces overall energy consumption compared to LEACH and BCDCP protocols.

  19. Continuous-flow leaching studies of crushed and cored SYNROC

    International Nuclear Information System (INIS)

    Both crushed (150 to 300 μm) and cored (1.8 mm diameter) samples of SYNROC have been leached with the single-pass continuous-flow leaching equipment. Crushed samples of Cs-hollandite were also leached in a similar experiment. Temperatures used were 25 and 750C and leachates were 0.03 N NaHCO3 and distilled water. Leaching rates from SYNROC C were ranked Cs > Sr greater than or equal to Ca > Ba > Zr. A comparison of leaching rates is made between crushed SYNROC, cored SYNROC, and PNL 76-68 glass beads. This comparison depends on how the surface areas are determined for each sample. Based on geometric surface areas for SYNROC cores and glass beads Cs leach rates from SYNROC compare well with both Na and Np leached from the glass. The other elements leached from SYNROC are lower than Na and Np leached from glass. They also vary for each element while glass shows nearly the same leach rate for both Na and Np

  20. Rejection of micropollutants by clean and fouled forward osmosis membrane.

    Science.gov (United States)

    Valladares Linares, Rodrigo; Yangali-Quintanilla, Victor; Li, Zhenyu; Amy, Gary

    2011-12-15

    As forward osmosis (FO) gains attention as an efficient technology to improve wastewater reclamation processes, it is fundamental to determine the influence of fouling in the rejection of emerging contaminants (micropollutants). This study focuses on the rejection of 13 selected micropollutants, spiked in a secondary wastewater effluent, by a FO membrane, using Red Sea water as draw solution (DS), differentiating the effects on the rejection caused by a clean and fouled membrane. The resulting effluent was then desalinated at low pressure with a reverse osmosis (RO) membrane, to produce a high quality permeate and determine the rejection with a coupled forward osmosis - low pressure reverse osmosis (FO-LPRO) system. When considering only FO with a clean membrane, the rejection of the hydrophilic neutral compounds was between 48.6% and 84.7%, for the hydrophobic neutrals the rejection ranged from 40.0% to 87.5%, and for the ionic compounds the rejections were between 92.9% and 96.5%. With a fouled membrane, the rejections were between 44.6% and 95.2%, 48.7%-91.5% and 96.9%-98.6%, respectively. These results suggest that, except for the hydrophilic neutral compounds, the rejection of the micropollutants is increased by the presence of a fouling layer, possibly due to the higher hydrophilicity of the FO fouled membrane compared to the clean one, the increased adsorption capacity of hydrophilic compounds and reduced mass transport capacity, membrane swelling, and the higher negative charge of the membrane surface, related to the foulants composition, mainly NOM acids (carboxylic radicals) and polysaccharides or polysaccharide-like substances. However, when coupled with RO, the rejections in both cases increased above 96%. The coupled FO-LPRO system was an effective double barrier against the selected micropollutants. PMID:22055122

  1. Rejection of micropollutants by clean and fouled forward osmosis membrane

    KAUST Repository

    Valladares Linares, Rodrigo

    2011-12-01

    As forward osmosis (FO) gains attention as an efficient technology to improve wastewater reclamation processes, it is fundamental to determine the influence of fouling in the rejection of emerging contaminants (micropollutants). This study focuses on the rejection of 13 selected micropollutants, spiked in a secondary wastewater effluent, by a FO membrane, using Red Sea water as draw solution (DS), differentiating the effects on the rejection caused by a clean and fouled membrane. The resulting effluent was then desalinated at low pressure with a reverse osmosis (RO) membrane, to produce a high quality permeate and determine the rejection with a coupled forward osmosis - low pressure reverse osmosis (FO-LPRO) system. When considering only FO with a clean membrane, the rejection of the hydrophilic neutral compounds was between 48.6% and 84.7%, for the hydrophobic neutrals the rejection ranged from 40.0% to 87.5%, and for the ionic compounds the rejections were between 92.9% and 96.5%. With a fouled membrane, the rejections were between 44.6% and 95.2%, 48.7%-91.5% and 96.9%-98.6%, respectively. These results suggest that, except for the hydrophilic neutral compounds, the rejection of the micropollutants is increased by the presence of a fouling layer, possibly due to the higher hydrophilicity of the FO fouled membrane compared to the clean one, the increased adsorption capacity of hydrophilic compounds and reduced mass transport capacity, membrane swelling, and the higher negative charge of the membrane surface, related to the foulants composition, mainly NOM acids (carboxylic radicals) and polysaccharides or polysaccharide-like substances. However, when coupled with RO, the rejections in both cases increased above 96%. The coupled FO-LPRO system was an effective double barrier against the selected micropollutants. © 2011 Elsevier Ltd.

  2. Rejected by Peers--Attracted to Antisocial Media Content: Rejection-Based Anger Impairs Moral Judgment among Adolescents

    Science.gov (United States)

    Plaisier, Xanthe S.; Konijn, Elly A.

    2013-01-01

    Adolescence is an important developmental stage during which both peers and the media have a strong influence. Both peer rejection and the use of morally adverse media are associated with negative developmental outcomes. This study examines processes by which peer rejection might drive adolescents to select antisocial media content by tying…

  3. Rejected by peers-attracted to antisocial media content: rejection-based anger impairs moral judgment among adolescents.

    Science.gov (United States)

    Plaisier, Xanthe S; Konijn, Elly A

    2013-06-01

    Adolescence is an important developmental stage during which both peers and the media have a strong influence. Both peer rejection and the use of morally adverse media are associated with negative developmental outcomes. This study examines processes by which peer rejection might drive adolescents to select antisocial media content by tying together developmental research on peer rejection and research on media effects. Assumed underlying mechanisms are rejection-based anger and frustration and the adolescent's moral judgment. A between-participants experimental design manipulated peer rejection versus acceptance in adolescents (Mage = 13.88 years; N = 74) and young adults (Mage = 21.37 years; N = 75), applying the Cyberball paradigm. Measures included the State Anger Inventory (STAXI) to assess feelings of rejection and the newly devised Media, Morals, and Youth Questionnaire (MMaYQue) to assess media preferences and moral judgment of media content. Using bootstrapping analyses, a double mediation was established: Higher levels of state anger in peer-rejected adolescents induced more tolerable moral judgments of antisocial media content, subsequently instigating a preference for antisocial media content. In contrast, the young adult sample showed no relations between peer rejection and antisocial media preference. Results are discussed within a downward spiral framework of combined peer and media influences. PMID:22799588

  4. DYNAMICS OF IRIG IN TREATMENT OF HEART TRANSPLANT REJECTIONS

    Directory of Open Access Journals (Sweden)

    A. O. Shevchenko

    2015-01-01

    Full Text Available In cardiac recipients non-invasive monitoring will identify the risk of acute rejection, as well as reduce the number of routine biopsies. The relation between the development of the transplanted heart rejection and the change of elastic properties of common carotid artery has been proved. Aim: to analyze dynamics of iRIG in treatment of graft rejection in heart recipients.Materials and methods. 59 heart recipients were examined: 21 patients (ptswithout rejection, 20 pts – with rejection after 1st biopsy, 15 pts – with rejection after 1st and 2 biopsies, 3 pts – with persistent rejection after all biopsies. iRIG was estimated using empirical equation.Results. Dynamics of iRIG in pts. without rejection according to all biopsies over time was not signifi cantly changed 6280 ± 2143, 6083 ± 2388, 6362 ± 1984 and 6188 ± 3012 cm/sec2 (p = 0.11, p = 0.13, p = 0.17 between the 1st and 2nd, 2nd and 3rd, 3rd and 4th values, respectively. In pts. with rejection iRIG decreased during treatment, but was signifi cantly higher even after successful treatment. In patients with persistent rejection iRIG did not decrease and tended to increase (17 459 ± 9702 cm/sec2 on the results of the 1st biopsy to 21 305 ± 10 448 cm/sec2 on the results of the 4th biopsy.Conclusions. In patients with heart transplant iRIG does not change signifi cantly with the time after transplantation. iRIG increases in all types of rejection, followed by its decrease in the course of therapy; in patients with persistent rejection iRIG remains high. Evaluation of iRIG can be used for non-invasive monitoring of patients after heart transplantations (HTx and to identify patients at high risk of transplant rejection.

  5. Lixiviação do glyphosate e do imazapyr em solos com diferentes texturas e composição química: II. método analítico Glyphosate and imazapyr leaching in soils with different textures and chemical composition: II. analytical method

    Directory of Open Access Journals (Sweden)

    Adailson P. de Souza

    1999-08-01

    Full Text Available Em razão das poucas de informações existente na literatura, sobre a mobilidade do glyphosate e do imazapyr, em solos de baixa atividade, comum em países tropicais, foi conduzido, em laboratório, um estudo sobre a mobilidade vertical desses herbicida s em dois solos com diferente s composições químicas e fisicas. Para estudar essa mobilidade, foram utilizadas colunas de solo com diferentes alturas, as quais, após aplicação dos produtos na dose comerc ial de 4 L ha-1, foram submetida s a um regime hídrico de 40 mm h-1, por um período de 4 h. As análises dos resíduos nas diferentes profundidades foram feitas utilizando-se os métodos voltamétrico (polarografia e HPLC, para o glyphosate e imazapyr, respectivame nte. Com base nos resultados, foi possível concluir que: a os métodos voltamétrico, para o glyphosate, e HPLC, para o imazapyr, são adequados para os estudos de identificação e quantificação de resíduos em água e solo; b os limites de quantificação dos resíduos foram de 0,4 μg mL-1 e 5 μg L-1 para o glyphosate e o imazapyr, respectivamente; c a taxa de recuperação do glyphosate, nas amostr as de solo (76 e 78% para os solos de Viçosa e Sabará, respectivamente foi menor que na amostra de água (83%; d a taxa de recuperação do imazapyr, em água e solo, foi próxima de 100%; e a lixiviação do glyphosate nos solos foi muito baixa; e f o imazapyr apresentou alta lix iviação, porém dif ere nciada entre os solos estudados, sendo essa maior no solo de tex tura franco -are nosa de Viçosa que no de argila de Sabará.Due to the scarce information available in the lit eratu re on the glyphosa te and imazapyr mobility in low activity soils, which is common in the tropical countries, a laboratory study was conducted on the vertical mobility of these herbicides in two soils with different physical and chemical compositions . For studying this mobility, the soil columns with different heights were submitted to a

  6. Equilibrium leach testing of low level waste. Pt. 1

    International Nuclear Information System (INIS)

    The equilibrium leach test was developed to simulate the chemical conditions in a repository after water has penetrated the near field barriers. The principal components of the repository (the waste, backfill and canister simulant) are equilibrated with water under static conditions to simulate the very low water flows likely to be encountered in the repository. The water is sampled at various times over a 1-2 year period and analysed for radionuclides. Equilibrium leach testing has now been extended to low level wastes and this report describes the effects of different backfill compositions. Later reports will deal with the effects of other variables. A series of experiments have been conducted using four different backfills with ferric floc sludge wastes in both oxidising and reducing environments. The water was sampled at 1, 3, 6 and 12 months and analysed for actinides, fission and activation products and inactive components. It was demonstrated that the activities released depended on the nature of the backfill but not very much on the redox potential of the system. Whereas fission and activation products generally reached steady state values by three months, this was not so for the actinides which had not reached a steady value even after twelve months. Initial experiments using membrane filters indicated this was partly due to the presence of colloidal material in the leachates. Similar tests for the inactive components of the leachates did not show any significant colloidal contribution from these elements except for iron and this only in a few cases. The role of these materials cannot be precluded however, since the amounts required to interact with actinides would be very small and might be difficult to detect. (author)

  7. Acute rejection episodes after kidney transplantation

    Directory of Open Access Journals (Sweden)

    Hamida Fethi

    2009-01-01

    Full Text Available Acute rejection episodes (AREs are a major determinant of renal allograft survival. The incorporation of new immunosuppressive agents explains, at least partially, the improvement seen in the results of transplantation in recent years. The objectives of this study are to analyze the incidence and severity of AREs, their risk factors and their influence on graft and patient survival. We retrospectively studied 280 kidney transplants performed in adults at the Charles Nicolle Hospital, Tunis, between 1986 and 2004. The diagnosis of ARE was based on clinical data and response to treatment. Allograft biopsies were performed in ten cases. The treatment of AREs consisted of pulse methylprednisolone and anti-thymocyte globulin. There were 186 males (66.4% and 94 females (33.6%, and their mean age was 31 ± 8.9 years. Overall, the 280 study patients experienced a total of 113 AREs. Of them, 85 had only one ARE, 28 had two to three and none had more than three AREs. A total of 68 AREs were completely re-versible, 42 were partially reversible while three could not be reversed with treatment. The mean inci-dence of AREs was 40.4%. The incidence was > 45% between 1986 and 1997, decreased to 20.5% between 1998 and 2000 and to 9% between 2001 and 2004. Graft survival rates in patients with and without AREs were respectively 91% and 93% at three years, 82% and 90% at five years and 73% and 83% at 10 years. We found a decrease in the incidence of AREs in recent years in our study patients, and this was related to the introduction of sensitized cross-match and the newer immunosuppressive agents, particularly MMF. Additionally, AREs had a deleterious impact on late graft survival in our study population.

  8. Leaching and recycling of zinc from liquid waste sediments

    Institute of Scientific and Technical Information of China (English)

    PENG Bing; GAO Hui-mei; CHAI Li-yuan; SHU Yu-de

    2008-01-01

    The selective leaching and recovery of zinc in a zinciferous sediment from a synthetic wastewater treatment was investigated. The main composition of the sediment includes 6% zinc and other metal elements such as Ca, Fe, Cu, Mg. The effects of sulfuric acid concentration, temperature, leaching time and the liquid-to-solid ratio on the leaching rate of zinc were studied by single factor and orthogonal experiments. The maximum difference of leaching rate between zinc and iron, 89.85%, was obtained by leaching under 170 g/L H2SO4 in liquid-to-solid ratio 4.2 mL/g at 65 "C for 1 h, and the leaching rates of zinc and iron were 91.20% and 1.35%, respectively.

  9. Separate neural representations for physical pain and social rejection.

    Science.gov (United States)

    Woo, Choong-Wan; Koban, Leonie; Kross, Ethan; Lindquist, Martin A; Banich, Marie T; Ruzic, Luka; Andrews-Hanna, Jessica R; Wager, Tor D

    2014-01-01

    Current theories suggest that physical pain and social rejection share common neural mechanisms, largely by virtue of overlapping functional magnetic resonance imaging (fMRI) activity. Here we challenge this notion by identifying distinct multivariate fMRI patterns unique to pain and rejection. Sixty participants experience painful heat and warmth and view photos of ex-partners and friends on separate trials. FMRI pattern classifiers discriminate pain and rejection from their respective control conditions in out-of-sample individuals with 92% and 80% accuracy. The rejection classifier performs at chance on pain, and vice versa. Pain- and rejection-related representations are uncorrelated within regions thought to encode pain affect (for example, dorsal anterior cingulate) and show distinct functional connectivity with other regions in a separate resting-state data set (N = 91). These findings demonstrate that separate representations underlie pain and rejection despite common fMRI activity at the gross anatomical level. Rather than co-opting pain circuitry, rejection involves distinct affective representations in humans.

  10. Separate neural representations for physical pain and social rejection.

    Science.gov (United States)

    Woo, Choong-Wan; Koban, Leonie; Kross, Ethan; Lindquist, Martin A; Banich, Marie T; Ruzic, Luka; Andrews-Hanna, Jessica R; Wager, Tor D

    2014-01-01

    Current theories suggest that physical pain and social rejection share common neural mechanisms, largely by virtue of overlapping functional magnetic resonance imaging (fMRI) activity. Here we challenge this notion by identifying distinct multivariate fMRI patterns unique to pain and rejection. Sixty participants experience painful heat and warmth and view photos of ex-partners and friends on separate trials. FMRI pattern classifiers discriminate pain and rejection from their respective control conditions in out-of-sample individuals with 92% and 80% accuracy. The rejection classifier performs at chance on pain, and vice versa. Pain- and rejection-related representations are uncorrelated within regions thought to encode pain affect (for example, dorsal anterior cingulate) and show distinct functional connectivity with other regions in a separate resting-state data set (N = 91). These findings demonstrate that separate representations underlie pain and rejection despite common fMRI activity at the gross anatomical level. Rather than co-opting pain circuitry, rejection involves distinct affective representations in humans. PMID:25400102

  11. Organ transplant tissue rejection: detection and staging by fluorescence spectroscopy

    Science.gov (United States)

    MacAulay, Calum E.; Whitehead, Peter D.; McManus, Bruce; Zeng, Haishan; Wilson-McManus, Janet; MacKinnon, Nick; Morgan, David C.; Dong, Chunming; Gerla, Paul; Kenyon, Jennifer

    1998-07-01

    Patients receiving heart or other organ transplants usually require some level of anti-rejection drug therapy, most commonly cyclosporine. The rejection status of the organ must be monitored to determine the optimal anti-rejection drug therapy. The current method for monitoring post-transplant rejection status of heart transplant patients consists of taking biopsies from the right ventricle. In this work we have developed a system employing optical and signal-processing techniques that will allow a cardiologist to measure spectral changes associated with tissue rejection using an optical catheter probe. The system employs time gated illumination and detection systems to deal with the dynamic signal acquisition problems associated with in vivo measurements of a beating heart. Spectral data processing software evaluates and processes the data to produce a simple numerical score. Results of measurements made on 100 excised transplanted isograft and allograft rat hearts have demonstrated the ability of the system to detect the presence of rejection and to accurately correlate the spectroscopic results with the ISHLT (International Society for Heart and Lung Transplantation) stage of rejection determined by histopathology. In vivo measurements using a pig transplant model are now in process.

  12. Spontaneous restoration of transplantation tolerance after acute rejection.

    Science.gov (United States)

    Miller, Michelle L; Daniels, Melvin D; Wang, Tongmin; Chen, Jianjun; Young, James; Xu, Jing; Wang, Ying; Yin, Dengping; Vu, Vinh; Husain, Aliya N; Alegre, Maria-Luisa; Chong, Anita S

    2015-01-01

    Transplantation is a cure for end-stage organ failure but, in the absence of pharmacological immunosuppression, allogeneic organs are acutely rejected. Such rejection invariably results in allosensitization and accelerated rejection of secondary donor-matched grafts. Transplantation tolerance can be induced in animals and a subset of humans, and enables long-term acceptance of allografts without maintenance immunosuppression. However, graft rejection can occur long after a state of transplantation tolerance has been acquired. When such an allograft is rejected, it has been assumed that the same rules of allosensitization apply as to non-tolerant hosts and that immunological tolerance is permanently lost. Using a mouse model of cardiac transplantation, we show that when Listeria monocytogenes infection precipitates acute rejection, thus abrogating transplantation tolerance, the donor-specific tolerant state re-emerges, allowing spontaneous acceptance of a donor-matched second transplant. These data demonstrate a setting in which the memory of allograft tolerance dominates over the memory of transplant rejection.

  13. Rejection of Organic Micropollutants by Clean and Fouled Nanofiltration Membranes

    Directory of Open Access Journals (Sweden)

    Lifang Zhu

    2015-01-01

    Full Text Available The rejection of organic micropollutants, including three polycyclic aromatic hydrocarbons (PAHs and three phthalic acid esters (PAEs, by clean and fouled nanofiltration membranes was investigated in the present study. The rejection of organic micropollutants by clean NF90 membranes varied from 87.9 to more than 99.9%, while that of NF270 membranes ranged from 32.1 to 92.3%. Clear time-dependence was observed for the rejection of hydrophobic micropollutants, which was attributed to the adsorption of micropollutants on the membrane. Fouling with humic acid had a negligible influence on the rejection of organic micropollutants by NF90 membranes, while considerable effects were observed with NF270 membranes, which are significantly looser than NF90 membranes. The observed enhancement in the rejection of organic micropollutants by fouled NF270 membranes was attributed to pore blocking, which was a dominating fouling mechanism for loose NF membranes. Changes in the ionic strength (from 10 to 20 mM reduced micropollutant rejection by both fouled NF membranes, especially for the rejection of dimethyl phthalate and diethyl phthalate by NF270 membranes (from 65.8 to 25.0% for dimethyl phthalate and 75.6 to 33.3% for diethyl phthalate.

  14. Impact of weather variability on nitrate leaching

    Science.gov (United States)

    Richards, Karl; Premrov, Alina; Hackett, Richard; Coxon, Catherine

    2016-04-01

    The loss of nitrate (NO3 - N) to water via leaching and overland flow contributes to eutrophication of freshwaters, transitional and near coastal waters with agriculture contributing significantly to nitrogen (N) loading to these water. Environmental regulations, such as the Nitrates and Water Framework Directives, have increased constraints on farmers to improve N management in regions at risk of NO3--N loss to water. In addition, farmers also have to manage their systems within a changing climate as the imapcts of climate change begin to impact resulting in more frequent extreme events such as floods and droughts. The objective of this study was to investigate the link between weather volatility and the concentration of leached NO3--N spring barley. Leaching was quantified under spring barley grown on a well-drained, gravelly sandy soil using ceramic cup samplers over 6 drainage years under the same farming practices and treatments. Soil solution NO3--N concentrations under spring barley grown by conventional inversion ploughing and reduced tillage were compared to weather parameters over the period. Weather was recorded at a national Met Eireann weather station on site. Soil solution NO3--N varied significantly between years. Within individual years NO3--N concentrations varied over the drainage season, with peak concentrations generally observed in the autumn time, decreasing thereafter. Under both treatments there was a three-fold difference in mean annual soil solution NO3--N concentration over the 6 years with no change in the agronomic practices (crop type, tillage type and fertiliser input). Soil solution nitrate concentrations were significantly influenced by weather parameters such as rainfall, effective drainage and soil moisture deficit. The impact of climate change in Ireland could lead to increased NO3--N loss to water further exacerbating eutrophication of sensitive estuaries. The increased impact on eutrophication of waters, related to climatic

  15. Leaching refuse after sphalerite mineral for extraction zinc and cobalt

    Directory of Open Access Journals (Sweden)

    S. Brožová

    2016-07-01

    Full Text Available The paper deals with a possibility of zinc and cobalt extraction from refuse after sphalerite mineral leaching. It contains theoretic analysis of hydrometallurgical processes. Practical part describes samples and their leaching in 10 % and 20 % sulphuric acid. In the end of the paper it is evaluated under which conditions the highest yield of zinc and cobalt from refuse after sulphide ore leaching is reached.

  16. Leaching of DOC, DN, and inorganic constituents from scrap tires.

    Science.gov (United States)

    Selbes, Meric; Yilmaz, Ozge; Khan, Abdul A; Karanfil, Tanju

    2015-11-01

    One concern for recycle and reuse of scrap tires is the leaching of tire constituents (organic and inorganic) with time, and their subsequent potential harmful impacts in environment. The main objective of this study was to examine the leaching of dissolved organic carbon (DOC), dissolved nitrogen (DN), and selected inorganic constituents from scrap tires. Different sizes of tire chips and crumb rubber were exposed to leaching solutions with pH's ranging from 3.0 to 10.0 for 28days. The leaching of DOC and DN were found to be higher for smaller size tire chips; however, the leaching of inorganic constituents was independent of the size. In general, basic pH conditions increased the leaching of DOC and DN, whereas acidic pH conditions led to elevated concentrations of metals. Leaching was minimal around the neutral pH values for all the monitored parameters. Analysis of the leaching rates showed that components associated with the rubbery portion of the tires (DOC, DN, zinc, calcium, magnesium, etc.) exhibited an initial rapid followed by a slow release. On the other hand, a constant rate of leaching was observed for iron and manganese, which are attributed to the metal wires present inside the tires. Although the total amounts that leached varied, the observed leaching rates were similar for all tire chip sizes and leaching solutions. Operation under neutral pH conditions, use of larger size tire chips, prewashing of tires, and removal of metal wires prior to application will reduce the impact of tire recycle and reuse.

  17. Leaching of vanadium from sulphuric acid manufacture spent catalysts

    OpenAIRE

    García, Diego Juan; Lozano Blanco, Luis Javier; Mulero Vivancos, María Dolores

    2001-01-01

    Recovery of vanadium contained in spent catalysts from the manufacture of sulphuric acid has been studied in this work, resulting in an industrial multistage process for the treatment of them avoiding direct deposition or dumping. Characterization of supplied spent catalysts samples, confirmed vanadium levels showed in the literature. The study of variables influencing leaching process: type of leaching agent, leaching agent concentration, S/L ratio, stirring speed and temperature, allows to ...

  18. Leaching refuse after sphalerite mineral for extraction zinc and cobalt

    OpenAIRE

    S. Brožová; J. Drápala; Kursa, M.; Pustějovská, P.; S. Jursová

    2016-01-01

    The paper deals with a possibility of zinc and cobalt extraction from refuse after sphalerite mineral leaching. It contains theoretic analysis of hydrometallurgical processes. Practical part describes samples and their leaching in 10 % and 20 % sulphuric acid. In the end of the paper it is evaluated under which conditions the highest yield of zinc and cobalt from refuse after sulphide ore leaching is reached. Web of Science 55 3 499 497

  19. Leaching of DOC, DN, and inorganic constituents from scrap tires.

    Science.gov (United States)

    Selbes, Meric; Yilmaz, Ozge; Khan, Abdul A; Karanfil, Tanju

    2015-11-01

    One concern for recycle and reuse of scrap tires is the leaching of tire constituents (organic and inorganic) with time, and their subsequent potential harmful impacts in environment. The main objective of this study was to examine the leaching of dissolved organic carbon (DOC), dissolved nitrogen (DN), and selected inorganic constituents from scrap tires. Different sizes of tire chips and crumb rubber were exposed to leaching solutions with pH's ranging from 3.0 to 10.0 for 28days. The leaching of DOC and DN were found to be higher for smaller size tire chips; however, the leaching of inorganic constituents was independent of the size. In general, basic pH conditions increased the leaching of DOC and DN, whereas acidic pH conditions led to elevated concentrations of metals. Leaching was minimal around the neutral pH values for all the monitored parameters. Analysis of the leaching rates showed that components associated with the rubbery portion of the tires (DOC, DN, zinc, calcium, magnesium, etc.) exhibited an initial rapid followed by a slow release. On the other hand, a constant rate of leaching was observed for iron and manganese, which are attributed to the metal wires present inside the tires. Although the total amounts that leached varied, the observed leaching rates were similar for all tire chip sizes and leaching solutions. Operation under neutral pH conditions, use of larger size tire chips, prewashing of tires, and removal of metal wires prior to application will reduce the impact of tire recycle and reuse. PMID:25712610

  20. PIXE/RBS as a tool to study cementitious materials: Application to the dynamic leaching of concrete

    Energy Technology Data Exchange (ETDEWEB)

    Llorente, I., E-mail: irene@cenim.csic.e [Centro Nacional de Investigaciones Metalurgicas (CENIM-CSIC), Avda Gregorio del Amo, 8, 28040 Madrid (Spain); Castellote, M. [Instituto de Ciencias de la Construccion ' Eduardo Torroja' (IETcc-CSIC), Serrano Galvache, 4, 28033 Madrid (Spain); Gonzalez-Arrabal, R. [Parque Cientifico de Madrid, Campus de Cantoblanco, Einstein 13, 28049 Madrid (Spain); Ynsa, M.D.; Munoz-Martin, A. [Centro de Microanalisis de Materiales (CMAM), Universidad Autonoma de Madrid, Campus de Cantoblanco, 28049 Madrid (Spain); Viedma, P.G. de; Castillo, A.; Martinez, I.; Andrade, C. [Instituto de Ciencias de la Construccion ' Eduardo Torroja' (IETcc-CSIC), Serrano Galvache, 4, 28033 Madrid (Spain); Zuloaga, P.; Ordonez, M. [Empresa Nacional de Residuos Radiactivos, S.A. (ENRESA), Emilio Vargas, 7, 28043 Madrid (Spain)

    2009-12-15

    The suitability of the application of Ion Beam Analysis (IBA) techniques such as Particle Induced X-ray Emission spectrometry (PIXE) and Rutherford Backscattering Spectrometry (RBS) to elemental depth profiling in concrete is analysed, studying hardened samples of concrete prior to and after a dynamic leaching test. A calibration of the data has been done by comparing the results obtained by IBA techniques with those obtained by Chemical and Thermogravimetric Analysis (TG/DTA). From PIXE and RBS data relevant information about the migration of minor elements, within the concrete matrix after leaching is obtained.

  1. Bacterial leaching of metal sulfides proceeds by two indirect mechanisms via thiosulfate or via polysulfides and sulfur

    Energy Technology Data Exchange (ETDEWEB)

    Schippers, A.; Sand, W. [Univ. Hamburg (Germany). Inst. fuer Allgemeine Botanik

    1999-01-01

    Bacterial leaching, the biooxidation of metal sulfides to soluble metal sulfates and sulfuric acid, is effected by specialized bacteria. The acid-insoluble metal sulfides FeS{sub 2}, MoS{sub 2}, and WS{sub 2} are chemically attacked by iron(III) hexahydrate ions, generating thiosulfate, which is oxidized to sulfuric acid. Other metal sulfides are attacked by iron(III) ions and by protons, resulting in the formation of elemental sulfur via intermediary polysulfides. Sulfur is biooxidized to sulfuric acid. This explains leaching of metal sulfides by Thiobacillus thiooxidans.

  2. Coupling GIS with Nitrogen Leaching Models

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Geographical information systems (GIS) are increasingly being applied to surface and subsurface flow and transport modeling issues. In this paper, more attentions are focused on the methodology and strategies of coupling GIS with non-point pollution models. Suggestions are made on how to best integrate current available or selected nitrogen leaching models, especially in the aspect of programming development so as to effectively and flexibly address the specific tasks. The new possibilities for dealing with non-point pollution problems at a regional scale are provided in the resulting integrated approach, including embedding grid-based GIS components in models.

  3. Lead sulphate leaching by sodium chloride solution

    OpenAIRE

    Conić Vesna T.; Pešovski Branka D.; Cvetkovski Vladimir B.; Stanojević-Šimšić Zdenka S.; Dragulović Suzana S.; Simonović Danijela B.; Dimitrijević Silvana B.

    2013-01-01

    Bioleaching treatment of complex multi-metallic Cu-Zn-Pb-Ag-Au mineral concentrates leds to the formation, besides easily soluble zinc and cooper sulphates, of hardly soluble lead (II) sulfate (PbSO4) sludge. To determine the leaching parameters of PbSO4 with NaCl in the bioleaching residue, lead sulphate solution was synthetically prepared. The effect of process parameters, namely NaCl concentration, solid:liquid phase ratio, processing time, temperature and Cl ions was examined. It wa...

  4. SCHEDULING WITH REJECTION AND NON-IDENTICAL JOB ARRIVALS

    Institute of Scientific and Technical Information of China (English)

    Zhigang CAO; Yuzhong ZHANG

    2007-01-01

    In this paper, we address the scheduling problem with rejection and non-identical job arrivals, in which we may choose not to process certain jobs and each rejected job incurs a penalty.Our goal is to minimize the sum of the total penalties of the rejected jobs and the maximum completion time of the processed ones. For the off-line variant, we prove its NP-hardness and present a PTAS, and for the on-line special case with two job arrivals, we design a best possible algorithm with competitive ratio (√5+1)/2.

  5. Suicide Screening for Prisoners: An Ethical Critique of Research Rejection.

    Science.gov (United States)

    Guinn, David; Burgermeister, Diane M

    2016-01-01

    A retrospective review of medical records was proposed to examine mental health staff compliance with documentation of a suicide assessment tool according to institutional policy on suicide screening within a U.S. correctional facility. A shift in focus was necessary when the proposed study was rejected by the institutional review board. Reasons for the rejection included low perceived benefit versus greater risk to the correctional facility and the need for prisoner informed consent, albeit the design was a retrospective medical record review. Because of this rejection, ethical issues in the prevention of suicide in prisons were examined with implications for the forensic nurse leading quality improvement initiatives.

  6. Preparation, sintering and leaching of optimized uranium thorium dioxides

    Science.gov (United States)

    Hingant, N.; Clavier, N.; Dacheux, N.; Barre, N.; Hubert, S.; Obbade, S.; Taborda, F.; Abraham, F.

    2009-03-01

    Mixed actinide dioxides are currently studied as potential fuels for several concepts associated to the fourth generation of nuclear reactors. These solids are generally obtained through dry chemistry processes from powder mixtures but could present some heterogeneity in the distribution of the cations in the solid. In this context, wet chemistry methods were set up for the preparation of U1-xThxO2 solid solutions as model compounds for advanced dioxide fuels. Two chemical routes of preparation, involving the precipitation of crystallized precursor, were investigated: on the one hand, a mixture of acidic solutions containing cations and oxalic acid was introduced in an open vessel, leading to a poorly-crystallized precipitate. On the other hand, the starting mixture was placed in an acid digestion bomb then set in an oven in order to reach hydrothermal conditions. By this way, small single-crystals were obtained then characterized by several techniques including XRD and SEM. The great differences in terms of morphology and crystallization state of the samples were correlated to an important variation of the specific surface area of the oxides prepared after heating, then the microstructure of the sintered pellets prepared at high temperature. Preliminary leaching tests were finally undertaken in dynamic conditions (i.e. with high renewal of the leachate) in order to evaluate the influence of the sample morphology on the chemical durability of the final cohesive materials.

  7. Cadmium leaching from thermal treated and gamma irradiated Mexican aluminosilicates

    Energy Technology Data Exchange (ETDEWEB)

    Davila-Rangel, J.I. [Departamento de Quimica, Instituto Nacional de Investigaciones Nucleares, Apdo. Postal 18-1027, Mexico 11801, D.F. (Mexico); Unidad Academica Centro Regional de Estudios Nucleares, Universidad Autonoma de Zacatecas Cipres 10, Frac. La Penuela, Zacatecas, Zacatecas 98068 (Mexico); Facultad de Ciencias, Universidad Autonoma del Estado de Mexico, Instituto Literario No. 100 Col. Centro C.P. 50000, Toluca, Edo. de Mexico (Mexico); Solache-Rios, M. [Departamento de Quimica, Instituto Nacional de Investigaciones Nucleares, Apdo. Postal 18-1027, Mexico 11801, D.F. (Mexico)], E-mail: msr@nuclear.inin.mx

    2008-10-15

    Thermal and radiation effects on the leaching of cadmium from two cadmium exchanged zeolitic tuffs and one clay were determined. The cadmium exchanged aluminosilicates were heated at different temperatures (500, 700, 900 and 1100 {sup o}C), and the materials were then treated with NaCl (1 M and 5 M) and HNO{sub 3} (0.001 M and 1 M) solutions to determine the leaching behaviour of cadmium from the materials. The stability of cadmium in the materials increased as the heating temperature was increased. Cadmium leaching from gamma irradiated and heated materials at 1100 {sup o}C was higher than leaching from non-irradiated samples.

  8. Leaching of polyphase nuclear waste ceramics: microstructural and phase characterization

    International Nuclear Information System (INIS)

    The leaching of complex polyphase nuclear waste ceramics is described in the context of the geochemically established dissolution behavior of the constituent phases. Static leach tests conducted on ceramic monoliths in deionized water, in simulated silicate, and in brine groundwaters, conforming to Materials Characterization Center standards and an accelerated, microscopic leach test, were used to identify the processes. Dissolution and formation of surface passivation layers are discussed in terms of hydrolysis and the adsorption of the metal hydroxocomplexes onto the monolith surface. The factors observed to affect dissolution are pertinent to the leaching of other polyphase nuclear waste ceramics. 11 figures, 1 table

  9. Effect of peroxodisulfate on uranium leaching with ammonium bicarbonate

    Directory of Open Access Journals (Sweden)

    Nurbek Nurpeisov

    2013-05-01

    Full Text Available In this study, uranium leaching from ore material using acid solution and bicarbonate in a presence peroxodisulfate ion was examined. For experiments two different tips of leaching methods were used: leaching in static and dynamic conditions. The determination of uranium concentrations in product solutions were analyzed by titrimetric (by ammonia vanadate solution method. The maximum yield of uranium leached with ammonium bicarbonate in a presence of ammonium peroxodisulfate (5 g/L was only 33%, which is half the corresponding value obtained by sulfuric acid (65%.

  10. Carbonate leaching of uranium and hydrogen peroxide stabilizer therefor

    International Nuclear Information System (INIS)

    In the carbonate leaching process for the solution mining of subterranean uranium containing formations in which an injection well is drilled and completed within the uranium formation; alkaline carbonate uranium leaching solution and sufficient hydrogen peroxide are injected through the injection wells into the formation whereby uranium values are produced from production wells, characterized by providing in the leaching solution a mixture of 1-hydroxyethylidene-1,1-diphosphonic acid and an alkali metal pyrophosphate in a weight ratio of from 1 to 10 to 10 to 1, the amount of said mixture being sufficient to inhibit decomposition of the hydrogen peroxide in said leaching solution

  11. Cadmium leaching from thermal treated and gamma irradiated Mexican aluminosilicates

    International Nuclear Information System (INIS)

    Thermal and radiation effects on the leaching of cadmium from two cadmium exchanged zeolitic tuffs and one clay were determined. The cadmium exchanged aluminosilicates were heated at different temperatures (500, 700, 900 and 1100 oC), and the materials were then treated with NaCl (1 M and 5 M) and HNO3 (0.001 M and 1 M) solutions to determine the leaching behaviour of cadmium from the materials. The stability of cadmium in the materials increased as the heating temperature was increased. Cadmium leaching from gamma irradiated and heated materials at 1100 oC was higher than leaching from non-irradiated samples

  12. Actinide speciation in glass leach-layers: An EXAFS study

    Energy Technology Data Exchange (ETDEWEB)

    Biwer, B.M.; Soderholm, L. [Argonne National Lab., IL (United States); Greegor, R.B. [Boeing Co., Seattle, WA (United States); Lytle, F.W. [EXAFS Co., Pioche, NV (United States)

    1996-12-31

    Uranium L{sub 3} X-ray absorption data were obtained from two borosilicate glasses, which are considered as models for radioactive wasteforms, both before and after leaching. Surface sensitivity to uranium speciation was attained by a novel application of simultaneous fluorescence and electron-yield detection. Changes in speciation are clearly discernible, from U(VI) in the bulk to (UO{sub 2}){sup 2+}-uranyl in the leach layer. The leach-layer uranium concentration variations with leaching times are also determined from the data.

  13. Influence of leaching on surface composition, microstructure, and valence band of single grain icosahedral Al-Cu-Fe quasicrystal

    Energy Technology Data Exchange (ETDEWEB)

    Lowe, M.; McGrath, R.; Sharma, H. R. [Surface Science Research Centre and The Department of Physics, The University of Liverpool, Liverpool L69 3BX (United Kingdom); Yadav, T. P. [Hydrogen Energy Centre, Department of Physics, Banaras Hindu University, Varanasi 221005 (India); Fournée, V.; Ledieu, J. [Institut Jean Lamour (UMR7198 CNRS-Université de Lorraine), Parc de Saurupt, 54011 Nancy Cedex (France)

    2015-03-07

    The use of quasicrystals as precursors to catalysts for the steam reforming of methanol is potentially one of the most important applications of these new materials. To develop application as a technology requires a detailed understanding of the microscopic behavior of the catalyst. Here, we report the effect of leaching treatments on the surface microstructure, chemical composition, and valence band of the icosahedral (i-) Al-Cu-Fe quasicrystal in an attempt to prepare a model catalyst. The high symmetry fivefold surface of a single grain i-Al-Cu-Fe quasicrystal was leached with NaOH solution for varying times, and the resulting surface was characterized by x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The leaching treatments preferentially remove Al producing a capping layer consisting of Fe and Cu oxides. The subsurface layer contains elemental Fe and Cu in addition to the oxides. The quasicrystalline bulk structure beneath remains unchanged. The subsurface gradually becomes Fe{sub 3}O{sub 4} rich with increasing leaching time. The surface after leaching exhibits micron sized dodecahedral cavities due to preferential leaching along the fivefold axis. Nanoparticles of the transition metals and their oxides are precipitated on the surface after leaching. The size of the nanoparticles is estimated by high resolution transmission microscopy to be 5-20 nm, which is in agreement with the AFM results. Selected area electron diffraction (SAED) confirms the crystalline nature of the nanoparticles. SAED further reveals the formation of an interface between the high atomic density lattice planes of nanoparticles and the quasicrystal. These results provide an important insight into the preparation of model catalysts of nanoparticles for steam reforming of methanol.

  14. Ashes from oily sewage sludge combustion: chemistry, mineralogy and leaching properties

    Directory of Open Access Journals (Sweden)

    Róbert Polc

    2016-07-01

    Full Text Available In the current paper the chemical and mineralogical properties of bottom ash and fly ash from oily sewage sludge combustion are investigated. The mineralogical composition and the morphology of ashes were determined by X-ray powder diffraction (XRD in combination with scanning electron microscopy with quantitative energy-dispersive X-ray microanalysis (SEM-EDX. In addition, a leaching test results are presented to shed light on the potential toxicity of studied materials and their impact on the environment is discussed. Both of the studied materials are final products of thermal oxidation at industrial sludge incinerator. This facility aims to sanitary disposal of mechanical and biological sludge from industrial wastewater treatment plant. Bottom ash and fly ash are relatively stable solid products with slightly different chemical and mineralogical composition that reflects their different origin – burning condition in furnace vs. flues gas cleaning technology. Leaching tests of both mentioned materials were implemented under laboratory conditions. The aim of the laboratory tests was to determine the possibility of the pollutants release into the environment. The data presented herein support the importance of detailed mineralogical and geochemical study for the better understanding of the leaching tests. The obtained results showed that both of the sewage sludge ash samples exceed the criteria for accepting waste in landfilles established for Slovakia.

  15. Soil spreading of liquid olive mill processing wastes impacts leaching of adsorbed terbuthylazine.

    Science.gov (United States)

    Aharonov-Nadborny, R; Raviv, M; Graber, E R

    2016-08-01

    Olive mill waste water (OMWW) is a major byproduct of the three phase olive oil production process. OMWW has high acidity (pH ∼ 4-5), high salt content (EC ∼ 5-10 mS cm(-1)), extremely high biological and chemical oxygen demand (BOD and COD up to 100,000 and 220,000 mg L(-1), respectively), and also high concentrations of organic compounds such as phenols and polyphenols. As a result, OMWW cannot be freely discharged into domestic wastewater treatment plants, but on-site treatment is very expensive and not sufficiently effective. Uses for OMWW such as agricultural recycling and co-composting were found to be impractical or expensive. Thus, OMWW is frequently spread on agricultural land for disposal. However, excessive or uncontrolled spreading of such organic-rich and saline wastewater could have many deleterious effects on soil quality, including salinization, phytotoxicity, or contaminant movement. The impact of OMWW on the leaching of adsorbed terbuthylazine, a soil-applied herbicide, was tested in four soils of varying physical and chemical properties. Although terbuthylazine solubility in OMWW is significantly higher than in water, leaching of adsorbed terbuthylazine from OMWW-treated soils was less than from control treatments. Low soil organic carbon and clay contents were major factors that contributed to reduced terbuthylazine leaching after soil treatment with OMWW. PMID:27179239

  16. Rejection of organic micro-pollutants from water by a tubular, hydrophilic pervaporative membrane designed for irrigation applications.

    Science.gov (United States)

    Sule, May N; Templeton, Michael R; Bond, Tom

    2016-01-01

    The links between chemical properties, including those relating to molecular size, solubility, hydrophobicity and vapour pressure, and rejection of model aromatic micro-pollutants by a tubular, hydrophilic polymer pervaporation membrane designed for irrigation applications were investigated. Open air experiments were conducted at room temperature for individual solutions of fluorene, naphthalene, phenol, 1,2-dichlorobenzene, 1,2-diethylbenzene and 2-phenoxyethanol. Percentage rejection generally increased with increased molecular size for the model micro-pollutants (47-86%). Molecular weight and log Kow had the strongest positive relationships with rejection, as demonstrated by respective correlation coefficients of r = 0.898 and 0.824. Rejection was also strongly negatively correlated with aqueous solubility and H-bond δ. However, properties which relate to vapour phase concentrations of the micro-pollutants were not well correlated with rejection. Thus, physicochemical separation processes, rather than vapour pressure, drive removal of aromatic contaminants by the investigated pervaporation tube. This expanded knowledge could be utilized in considering practical applications of pervaporative irrigation systems for treating organic-contaminated waters such as oilfield-produced waters. PMID:26585567

  17. An Analytical Model Approach for the Dissolution Kinetics of Magnesite Ore Using Ascorbic Acid as Leaching Agent

    Directory of Open Access Journals (Sweden)

    Nadeem Raza

    2013-01-01

    Full Text Available Ascorbic acid was used as leaching agent to investigate the dissolution kinetics of natural magnesite ore. The effects of various reaction parameters such as acid concentration, liquid-solid ratio, particle size, stirring speed, and temperature were determined on dissolution kinetics of the magnesite ore. It was found that the dissolution rate increased with increase in acid concentration, liquid-solid ratio, stirring speed, and temperature and decrease in the particle size of the ore. The graphical and statistical methods were applied to analyze the kinetic data, and it was evaluated that the leaching process was controlled by the chemical reaction, that is, . The activation energy of the leaching process was found to be 57.244 kJ mol−1 over the reaction temperature range from 313 to 343 K.

  18. YACON INULIN LEACHING DURING HOT WATER BLANCHING

    Directory of Open Access Journals (Sweden)

    Caroline Fenner Scher

    2015-10-01

    Full Text Available ABSTRACTYacon roots contain inulin, which has prebiotic properties and it may be used as sucrose or fat substitutes. However, inulin is very soluble in water. The loss of this important nutrient during blanching is caused mainly by diffusion or leaching, which might be diminished if blanching temperature - time conditions are correctly employed. The aim of this study was to determine the leaching of the sugars inulin, glucose and fructose, present in yacon roots, during hot water blanching under different time/temperature conditions. The samples were cleaned and peeled and cut into geometric forms of 1.75 ± 0.35 mm thick disks. A complete factorial experimental design was used, and the treatments of the samples were compared using the Tukey test. The results indicated that the time and temperature were significant in the dissolution of the sugars. The lowest inulin losses occurred at temperatures and times lower than 60 ºC and 3 minutes. For all temperatures, the lowest glucose and fructose losses were obtained at time lower than 3 and 5 minutes, respectively.

  19. PAHs leaching test for solidified waste

    Energy Technology Data Exchange (ETDEWEB)

    Henzler, R.; Grathwohl, P. [Tuebingen Univ. (Germany). Center for Applied Geoscience

    2003-07-01

    The treatment of waste materials to allow recycling or safe disposal is a rapidly expanding business, but also subject to increasing public awareness of enviromental issues and tightening of the regularise governing in many countries. One of the most widely used treatment for wastes is stabilisation /solidification using a cement matrix to obtain a monolithic residue. The most common test procedure to assess the risks of contaminant release into water (seepage, surface and groundwater) is the so-called ''tank leaching test'' or ''diffusion test'' (NEN 7345, Mulder et al 2001, Hohberg et al 2000), in which a solidified specimen is leached with water during different periods of time. The tests are usually done at room temperatures between 20 C and 25 C. However, the temperature under natural conditions are lower resulting in lower contaminant release rates. (subsurface temperature: 5 C - 10 C). If the thermodynamics of the contaminant release, especially the activation energy of desorption and diffusion, is known, it is possible to estimate the contaminant release for lower temperatures, e.g. down to groundwater temperatures. In addition the test can be accelerated if performed at high temperatures.

  20. Heterogeneous LEACH Protocol for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Nishi Sharma

    2013-07-01

    Full Text Available Wireless Sensor Networks are networks of large number of tiny, battery powered sensor nodes having limited on-board storage, processing, and radio capabilities. Nodes sense and send their reports toward a processing center which is called base station. Since this transmission and reception process consumes lots of energy as compare to data processing, Designing protocols and applications for such networks has to be energy aware in order to prolong the lifetime of the network. Generally, real life applications deal with such Heterogeneity rather than Homogeneity. In this paper, a protocol is proposed, which is heterogeneous in energy. We analyze the basic distributed clustering routing protocol LEACH (Low Energy Adaptive Clustering Hierarchy, which is a homogeneous system, and then we study the impact of heterogeneity in energy of nodes to prolong the life time of WSN. Simulation results using MATLAB shows that the proposed Leach-heterogeneous system significantly reduces energy consumption and increase the total lifetime of the wireless sensor network.

  1. Transmission Time and Throughput analysis of EEE LEACH, LEACH and Direct Transmission Protocol: A Simulation Based Approach

    Directory of Open Access Journals (Sweden)

    Meenakshi Sharma

    2012-10-01

    Full Text Available This paper gives a brief description about some routing protocols like EEE LEACH, LEACH and DirectTransmission protocol (DTx in Wireless Sensor Network (WSN and a comparison study of theseprotocols based on some performance matrices. Addition to this an attempt is done to calculate theirtransmission time and throughput. To calculate these, MATLAB environment is used. Finally, on the basisof the obtained results from the simulation, the above mentioned three protocols are compared. Thecomparison results show that, the EEE LEACH routing protocol has a greater transmission time thanLEACH and DTx protocol and with smaller throughput

  2. Transmission Time and Throughput analysis of EEE LEACH, LEACH and Direct Transmission Protocol: A Simulation Based Approach

    Directory of Open Access Journals (Sweden)

    Meenakshi Sharma

    2012-12-01

    Full Text Available This paper gives a brief description about some routing protocols like EEE LEACH, LEACH and DirectTransmission protocol (DTx in Wireless Sensor Network (WSN and a comparison study of theseprotocols based on some performance matrices. Addition to this an attempt is done to calculate theirtransmission time and throughput. To calculate these, MATLAB environment is used. Finally, on the basisof the obtained results from the simulation, the above mentioned three protocols are compared. Thecomparison results show that, the EEE LEACH routing protocol has a greater transmission time thanLEACH and DTx protocol and with smaller throughput.

  3. Non-clairvoyant weighted flow time scheduling with rejection penalty

    DEFF Research Database (Denmark)

    Chan, Ho-Leung; Chan, Sze-Hang; Lam, Tak-Wah;

    2012-01-01

    This paper initiates the study of online scheduling with rejection penalty in the non-clairvoyant setting, i.e., the size (processing time) of a job is not assumed to be known at its release time. In the rejection penalty model, jobs can be rejected with a penalty, and the user cost of a job is...... defined as the weighted flow time of the job plus the penalty if it is rejected before completion. Previous work on minimizing the total user cost focused on the clairvoyant single-processor setting [BBC+03,CLL11] and has produced O(1)-competitive online algorithm for jobs with arbitrary weights and...... results assume a processor running at a fixed speed. This paper shows more interesting results on extending the above study to the dynamic speed scaling model, where the processor can vary the speed dynamically and the rate of energy consumption is an arbitrary increasing function of speed. A scheduling...

  4. Community rejection following sexual assault as ‘forced migration’

    Directory of Open Access Journals (Sweden)

    AJ Morgen

    2013-09-01

    Full Text Available When women are banished from their communities following sexual assault, this rejection should be considered an act of forced migration by the administrators of truth commission reparations programmes.

  5. Stem Cells Transplanted in Monkeys without Anti-Rejection Drugs

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_160989.html Stem Cells Transplanted in Monkeys Without Anti-Rejection Drugs Scientists say goal is to create banks of stem cells that could be used for any human patient ...

  6. Hyperacute Rejection of a Living Unrelated Kidney Graft

    Directory of Open Access Journals (Sweden)

    Dietlind Tittelbach-Helmrich

    2014-01-01

    Full Text Available We present a case report of a 59-year-old man, who received a blood group identical living unrelated kidney graft. This was his second kidney transplantation. Pretransplant T-cell crossmatch resulted negative. B-cell crossmatch, which is not considered a strict contraindication for transplantation, resulted positive. During surgery no abnormalities occurred. Four hours after the transplantation diuresis suddenly decreased. In an immediately performed relaparotomy the transplanted kidney showed signs of hyperacute rejection and had to be removed. Pathological examination was consistent with hyperacute rejection. Depositions of IgM or IgG antibodies were not present in pathologic evaluation of the rejected kidney, suggesting that no irregular endothelial specific antibodies had been involved in the rejection. We recommend examining more closely recipients of second allografts, considering not only a positive T-cell crossmatch but also a positive B-cell crossmatch as exclusion criteria for transplantation.

  7. Surface modifications on InAs decrease indium and arsenic leaching under physiological conditions

    Energy Technology Data Exchange (ETDEWEB)

    Jewett, Scott A. [Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907 (United States); Yoder, Jeffrey A. [Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University of North Carolina-Chapel Hill, Raleigh, NC 27695 (United States); Center for Comparative Medicine and Translational Research, North Carolina State University of North Carolina-Chapel Hill, Raleigh, NC 27695 (United States); Ivanisevic, Albena, E-mail: ivanisevic@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University of North Carolina-Chapel Hill, Raleigh, NC 27695 (United States); Joint Department of Biomedical Engineering North Carolina State University/University of North Carolina-Chapel Hill, Raleigh, NC 27695 (United States)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer InAs was assessed under physiological conditions. Black-Right-Pointing-Pointer A thiol-alcohol and a PEG-based polymer layers demonstrated the highest stability. Black-Right-Pointing-Pointer Unmodified and modified InAs showed no toxicity to zebrafish up to 120 h post fertilization. - Abstract: Devices containing III-V semiconductors such as InAs are increasingly being used in the electronic industry for a variety of optoelectronic applications. Furthermore, the attractive chemical, material, electronic properties make such materials appealing for use in devices designed for biological applications, such as biosensors. However, in biological applications the leaching of toxic materials from these devices could cause harm to cells or tissue. Additionally, after disposal, toxic inorganic materials can leach from devices and buildup in the environment, causing long-term ecological harm. Therefore, the toxicity of these materials along with their stability in physiological conditions are important factors to consider. Surface modifications are one common method of stabilizing semiconductor materials in order to chemically and electronically passivate them. Such surface modifications could also prevent the leaching of toxic materials by preventing the regrowth of the unstable surface oxide layer and by creating an effective barrier between the semiconductor surface and the surrounding environment. In this study, various surface modifications on InAs are developed with the goal of decreasing the leaching of indium and arsenic. The leaching of indium and arsenic from modified substrates was assessed in physiological conditions using inductively coupled plasma mass spectrometry (ICP-MS). Substrates modified with 11-mercapto-1-undecanol (MU) and graft polymerized with poly(ethylene) glycol (PEG) were most effective at preventing indium and arsenic leaching. These surfaces were characterized using contact angle analysis, ellipsometry

  8. Leaching assessment of radioactive and non-radioactive elements from Brazilian phosphogypsum

    International Nuclear Information System (INIS)

    Phosphogypsum is a high volume by-product from phosphoric acid industries. Due to presence of certain impurities, mainly naturally-occurring radionuclides, this material has restriction for its use as building material and soil amendment. Then, phosphogypsum currently produced has been stacked near industries. To obtain more detailed information about the physico-chemical availability of heavy metals and radionuclides (Al, Ba, Cr, Fe, Mn, Th, U, Zn, Ra-226, Ra-228, Pb-210) in Brazilian phosphogypsum, three leaching procedures (sequential extraction, toxicity characteristic leaching procedure and soil fertility) were applied in samples from two phosphoric acid industries. Results indicated that the major fraction of heavy metals and radionuclides is associated with phosphogypsum lattice structure. (author)

  9. Kinetics of the Leaching Process of an Australian Gibbsitic Bauxite by Hydrochloric Acid

    Directory of Open Access Journals (Sweden)

    Aichun Zhao

    2016-01-01

    Full Text Available Gibbsitic bauxite from Australia was leached by hydrochloric acid in this work. Analysis on kinetics for the extraction of Al2O3 was quantitatively studied. It was concluded that the hydrochloric acid leaching process of gibbsitic bauxite was controlled by chemical reaction. Moreover, the mechanism for the dissolution followed the equation, ln⁡k=39.44-1.66×104(1/T, with an apparent activation energy of 137.90 kJ/mol, according to the equation of k=Ae-Ea/RT. This work aims to provide a good theory support for the process control by using a new method of alumina production from the low grade bauxite.

  10. Factors affecting the leaching of radium-226 from barium-radium sulphate sludges

    International Nuclear Information System (INIS)

    The National Uranium Tailings Program was established in 1982 to develop, in part, a mathematical predictive model which would allow the assessment of the impact of uranium mill tailings on the environment and particularly on humans. To achieve this, various studies were undertaken to establish the role played by key constituents of the tailings. This paper summarizes the findings of a study carried out under that program, to examine the leachability of barium-radium sulphate sludges produced in the treatment of uranium mill tailings decants. The investigators performed detailed chemical analysis of the sludge, applied geochemical computer models to investigate sludge leaching behaviour, and conducted experiments to assess the impact of bacteria on leaching. The modelling showed that the redox state of the sludge-leachant system was the most important factor. Substantial bacterially-mediated dissolution of the sludge and release of radium was demonstrated experimentally under suitable reducing conditions

  11. Hydrometallurgical process for zinc recovery from electric arc furnace dust (EAFD): part I: Characterization and leaching by diluted sulphuric acid.

    Science.gov (United States)

    Oustadakis, P; Tsakiridis, P E; Katsiapi, A; Agatzini-Leonardou, S

    2010-07-15

    The present paper is the first of a series of two articles dealing with the development of an integrated process for the recovery of zinc from electric arc furnace dust (EAFD), a hazardous industrial waste generated in the collection of particulate material during steelmaking process via electric arc furnace. Part I presents the EAFD characterization and its leaching process by diluted sulphuric acid, whereas Part II deals with the purification of the leach liquor and the recovery of zinc by solvent extraction/electrowinning. The characterization of the examined electric arc furnace dust was carried out by using granulometry analysis, chemical analysis, X-ray diffraction (XRD), thermogravimetric/differential thermal analysis (TG/DTA) and scanning electron microscopy (SEM). The leaching process was based on the Zn extraction with diluted sulphuric acid from EAFD under atmospheric conditions and without using any preliminary treatment. Statistical design and analysis of experiments were used, in order to determine the main effects and interactions of the leaching process factors, which were: acid normality, temperature and solid to liquid ratio. The zinc recovery efficiency on the basis of EAFD weight reached 80%. X-ray diffraction and scanning electron microscopy were used for the characterization of the leached residues.

  12. Mapping ground water vulnerability to pesticide leaching with a process-based metamodel of EuroPEARL.

    Science.gov (United States)

    Tiktak, A; Boesten, J J T I; van der Linden, A M A; Vanclooster, M

    2006-01-01

    To support EU policy, indicators of pesticide leaching at the European level are required. For this reason, a metamodel of the spatially distributed European pesticide leaching model EuroPEARL was developed. EuroPEARL considers transient flow and solute transport and assumes Freundlich adsorption, first-order degradation and passive plant uptake of pesticides. Physical parameters are depth dependent while (bio)-chemical parameters are depth, temperature, and moisture dependent. The metamodel is based on an analytical expression that describes the mass fraction of pesticide leached. The metamodel ignores vertical parameter variations and assumes steady flow. The calibration dataset was generated with EuroPEARL and consisted of approximately 60,000 simulations done for 56 pesticides with different half-lives and partitioning coefficients. The target variable was the 80th percentile of the annual average leaching concentration at 1-m depth from a time series of 20 yr. The metamodel explains over 90% of the variation of the original model with only four independent spatial attributes. These parameters are available in European soil and climate databases, so that the calibrated metamodel could be applied to generate maps of the predicted leaching concentration in the European Union. Maps generated with the metamodel showed a good similarity with the maps obtained with EuroPEARL, which was confirmed by means of quantitative performance indicators. PMID:16825441

  13. Pesticide leaching FOCUS scenarios if only dissolved pesticides degrade: re-assessing the importance of soil water flow

    Science.gov (United States)

    Te Brake, B.; van der Zee, S. E. A. T. M.; Verhoef, A.

    2009-04-01

    Although the pesticide screening policies assume that both dissolved and adsorbed pesticides are subject to transformation (or degradation), it is debatable whether this assumption is correct. Instead, it has been proposed that only dissolved pesticides may degrade, in line with the consensus on other organic contaminants for which only the dissolved or easily accessible fractions are biodegradable. If only dissolved pesticide fractions can degrade, this has major impacts on the pesticide risk assessment in the EU, which so far assumes all pesticide can degrade, whatever their chemical forms. In particular, if only dissolved pesticide degrades, the sorption process becomes completely irrelevant for the long term leached fraction: both regarding its (non)equilibrium and its (non)linearity assumptions. If sorption as such becomes less important, other processes should become more important for the leached fraction, and water flow as the major driving force is a logical candidate. Indeed, the rate of leaching can be shown to depend significantly on the net precipitation, with some prominent adjustments, if sorption becomes less dominant than in the current pesticide screening approaches. It will be shown that the celerity of leaching depends differently on the water flow, than does the leached fraction (which is crucial for pesticide admission policies). Therefore, a reconsideration of EU pesticide screening and admission policies may be necessary.

  14. Acidification processes and soil leaching influenced by agricultural practices revealed by strontium isotopic ratios

    Science.gov (United States)

    Pierson-Wickmann, Anne-Catherine; Aquilina, Luc; Weyer, Christina; Molénat, Jérôme; Lischeid, Gunnar

    2009-08-01

    In natural river systems, the chemical and isotopic composition of stream- and ground waters are mainly controlled by the geology and water-rock interactions. The leaching of major cations from soils has been recognized as a possible consequence of acidic deposition from atmosphere for over 30 years. Moreover, in agricultural areas, the application of physiological acid fertilizers and nitrogen fertilizers in the ammonia form may enhance the cation leaching through the soil profile into ground- and surface waters. This origin of leached cations has been studied on two small and adjacent agricultural catchments in Brittany, western France. The study catchments are drained by two first-order streams, and mainly covered with cambisoils, issued from the alteration and weathering of a granodiorite basement. Precipitations, soil water- and NH 4 acetate-leachates, separated minerals, and stream waters have been investigated. Chemical element ratios, such as Ba/Sr, Na/Sr and Ca/Sr ratios, as well as Sr isotopic ratios are used to constrain the relative contribution from potential sources of stream water elements. Based on Sr isotopic ratio and element concentration, soil water- and NH 4 acetate leaching indicates (1) a dominant manure/slurry contribution in the top soil, representing a cation concentrated pool, with low 87Sr/ 86Sr ratios; (2) in subsoils, mineral dissolution is enhanced by fertilizer application, becoming the unique source of cations in the saprolite. The relatively high weathering rates encountered implies significant sources of cations which are not accessory minerals, but rather plagioclase and biotite dissolution. Stream water has a very different isotopic and chemical composition compared to soil water leaching suggesting that stream water chemistry is dominated by elements issued from mineral and rock weathering. Agriculture, by applications of chemical and organic fertilizers, can influence the export of major base cations, such as Na +. Plagioclase

  15. Main feed water pump NPSH control during load rejection transient

    International Nuclear Information System (INIS)

    The paper introduces the damage to the Main feed water pump because of pump cavitation, analysis the disadvantaged impact of pressure reducing during load rejection transient condition, and the characteristic for Main feedwater pump NPSH during load rejection transient condition; summarizes the characteristics of Main feedwater pump NPSH comparing to NPQJVC. What's more, this paper has a lot for commissioning and running the Main feedwater pump. (author)

  16. Fate of manuscripts rejected for publication in the AJR.

    Science.gov (United States)

    Chew, F S

    1991-03-01

    The fate of rejected manuscripts that were originally submitted to the American Journal of Roentgenology (AJR) during the first 5 months of 1986 was investigated to learn whether, when, and where they had been published. AJR, a peer-reviewed journal of diagnostic radiology with a circulation of over 21,000, annually publishes about 500 papers and receives over 11,500 citations. MEDLINE searches conducted 45 to 54 months after the dates of rejection by AJR located 162 (64%) published papers out of a consecutive series of 254 manuscripts rejected by AJR, including 69% of the rejected major papers and 62% of the rejected case reports. The papers had been published in 30 different radiologic and 27 different nonradiologic journals. Most of these journals published fewer papers, had smaller circulations, and had lower impact factors (a ratio of citations received to papers published) than AJR does. The mean time lapse between rejection by AJR and publication in other journals was 15 months. The delay in publication was greater for papers published in nonradiologic and foreign journals than for papers published in radiologic and American journals. The results of this study indicate that rejection of a manuscript by a peer-reviewed journal such as AJR delays but by no means precludes publication. At least 82% of the major papers and 70% of the case reports that are submitted to AJR are eventually published, either in AJR or elsewhere. Because a scientific paper represents not only many hours of writing and manuscript preparation but also a great investment of research time and resources, authors are reluctant to abandon rejected manuscripts. In the majority of cases, submission to other journals gains acceptance and publication. PMID:1899764

  17. Multivisceral transplantation in pigs: a clinicopathological analysis of tissue rejection.

    OpenAIRE

    Mitsuoka,Shintaro; Tanaka,Noriaki; Orita, Kunzo

    1995-01-01

    In this study, we established the surgical procedure and postoperative care of multivisceral transplantation (MVTX) in pigs, and examined the functional changes and rejection pattern of transplanted organs in MVTX. Twenty-two MVTXs were performed without immunosuppression, and nine cases (41%) that survived for 5 days or more after MVTX were used for evaluation. Rejection in grafts including the liver, pancreas, and gastrointestinal tract were assessed histopathologically. On day 5 after tran...

  18. On Properties of Update Sequences Based on Causal Rejection

    OpenAIRE

    Eiter, T.; Fink, M; Sabbatini, G; Tompits, H.

    2001-01-01

    We consider an approach to update nonmonotonic knowledge bases represented as extended logic programs under answer set semantics. New information is incorporated into the current knowledge base subject to a causal rejection principle enforcing that, in case of conflicts, more recent rules are preferred and older rules are overridden. Such a rejection principle is also exploited in other approaches to update logic programs, e.g., in dynamic logic programming by Alferes et al. We give a thoroug...

  19. Effects of various uranium leaching procedures on soil: Short-term vegetation growth and physiology. Progress report, April 1994

    International Nuclear Information System (INIS)

    Significant volumes of soil containing elevated levels of uranium exist in the eastern United States. The contamination resulted from the development of the nuclear industry in the United States requiring a large variety of uranium products. The contaminated soil poses a collection and disposal problem of a magnitude that justifies the development of decontamination methods. Consequently, the Department of Energy (DOE) Office of Technology Development formed the Uranium Soils Integrated Demonstration (USID) program to address the problem. The fundamental goal of the USID task group has been the selective extraction/leaching or removal of uranium from soil faster, cheaper, and safer than what can be done using current conventional technologies. The objective is to selectively remove uranium from soil without seriously degrading the soil's physicochemical characteristics and without generating waste that is difficult to manage and/or dispose of. However, procedures developed for removing uranium from contaminated soil have involved harsh chemical treatments that affect the physicochemical properties of the soil. The questions are (1) are the changes in soil properties severe enough to destroy the soil's capacity to support and sustain vegetation growth and survival? and (2) what amendments might be made to the leached soil to return it to a reasonable vegetation production capacity? This study examines the vegetation-support capacity of soil that had been chemically leached to remove uranium. The approach is to conduct short-term germination and phytotoxicity tests for evaluating soils after they are subjected to various leaching procedures followed by longer term pot studies on successfully leached soils that show the greatest capacity to support plant growth. This report details the results from germination and short-term phytotoxicity testing of soils that underwent a variety of leaching procedures at the bench scale at ORNL and at the pilot plant at Fernald

  20. Leaching of hazardous substances from a composite construction product – An experimental and modelling approach for fibre-cement sheets

    Energy Technology Data Exchange (ETDEWEB)

    Lupsea, Maria [University of Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse (France); INRA, UMR 792, F-31400 Toulouse (France); CNRS, UMR 5504, F-31400 Toulouse (France); Paris–Est University, CSTB–Scientific and Technical Centre for the Building Industry, DEE/Environmentand Life Cycle Engineering Team, 24 rue Joseph Fourier, F–38400 Saint Martin d’Hères (France); Tiruta-Barna, Ligia, E-mail: ligia.barna@insa-toulouse.fr [University of Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse (France); INRA, UMR 792, F-31400 Toulouse (France); CNRS, UMR 5504, F-31400 Toulouse (France); Schiopu, Nicoleta [Paris–Est University, CSTB–Scientific and Technical Centre for the Building Industry, DEE/Environmentand Life Cycle Engineering Team, 24 rue Joseph Fourier, F–38400 Saint Martin d’Hères (France)

    2014-01-15

    Highlights: • Biocide and heavy metals leaching from fibre-cement sheet was investigated. • Equilibrium and dynamic leaching tests were used as modelling support. • The chemical-transport model identifies the main fixation/solubilisation mechanisms. • Biocides as terbutryn and boron were released by the commercial product. • FCS exhibit a cement-like leaching behaviour with high organic carbon release. -- Abstract: The leaching behaviour of a commercial fibre-cement sheet (FCS) product has been investigated. A static pH dependency test and a dynamic surface leaching test have been performed at lab scale. These tests allowed the development of a chemical-transport model capable to predict the release of major and trace elements over the entire pH range, in function of time. FCS exhibits a cement-type leaching behaviour with respect to the mineral species. Potentially hazardous species are released in significant quantities when compared to their total content. These are mainly heavy metals commonly encountered in cement matrixes and boron (probably added as biocide). Organic compounds considered as global dissolved carbon are released in significant concentrations, originating probably from the partial degradation of the organic fibres. The pesticide terbutryn (probably added during the preservative treatment of the organic fibres) was systematically identified in the leachates. The simulation of an upscaled runoff scenario allowed the evaluation of the cumulative release over long periods and the distribution of the released quantities in time, in function of the local exposure conditions. After 10 years of exposure the release reaches significant fractions of the species’ total content – going from 4% for Cu to near 100% for B.

  1. Leaching of hazardous substances from a composite construction product – An experimental and modelling approach for fibre-cement sheets

    International Nuclear Information System (INIS)

    Highlights: • Biocide and heavy metals leaching from fibre-cement sheet was investigated. • Equilibrium and dynamic leaching tests were used as modelling support. • The chemical-transport model identifies the main fixation/solubilisation mechanisms. • Biocides as terbutryn and boron were released by the commercial product. • FCS exhibit a cement-like leaching behaviour with high organic carbon release. -- Abstract: The leaching behaviour of a commercial fibre-cement sheet (FCS) product has been investigated. A static pH dependency test and a dynamic surface leaching test have been performed at lab scale. These tests allowed the development of a chemical-transport model capable to predict the release of major and trace elements over the entire pH range, in function of time. FCS exhibits a cement-type leaching behaviour with respect to the mineral species. Potentially hazardous species are released in significant quantities when compared to their total content. These are mainly heavy metals commonly encountered in cement matrixes and boron (probably added as biocide). Organic compounds considered as global dissolved carbon are released in significant concentrations, originating probably from the partial degradation of the organic fibres. The pesticide terbutryn (probably added during the preservative treatment of the organic fibres) was systematically identified in the leachates. The simulation of an upscaled runoff scenario allowed the evaluation of the cumulative release over long periods and the distribution of the released quantities in time, in function of the local exposure conditions. After 10 years of exposure the release reaches significant fractions of the species’ total content – going from 4% for Cu to near 100% for B

  2. Higher boron rejection with a new TFC forward osmosis membrane

    KAUST Repository

    Valladares Linares, Rodrigo

    2014-07-17

    Due to the stringent limits for boron in drinking and irrigation water, water treatment facilities have to incur additional treatment to remove boron down to a safe concentration. Forward osmosis (FO) is a membrane technology that may reduce the energy required to remove boron present in seawater. In direct FO desalination hybrid systems, fresh water is recovered from seawater using a recoverable draw solution, FO membranes are expected to show high boron rejection. This study focuses on determining the boron rejection capabilities of a new generation thin-film composite (TFC) FO membrane compared to a first generation cellulose triacetate (CTA) FO membrane. The effects of water permeate flux, membrane structure, draw solute charge, and reverse solute flux on boron rejection were determined. For TFC and CTA FO membranes, experiments showed that when similar operating conditions are applied (e.g. membrane type and draw solute type) boron rejection decreases with increase in permeate flux. Reverse draw solute flux and membrane fouling have no significant impact on boron rejection. Compared to the first generation CTA FO membrane operated at the same conditions, the TFC FO membrane showed a 40% higher boron rejection capability and a 20% higher water flux. This demonstrates the potential for boron removal for new generation TFC FO membranes. © 2014 © 2014 Balaban Desalination Publications. All rights reserved.

  3. B cells mediate chronic allograft rejection independently of antibody production.

    Science.gov (United States)

    Zeng, Qiang; Ng, Yue-Harn; Singh, Tripti; Jiang, Ke; Sheriff, Khaleefathullah A; Ippolito, Renee; Zahalka, Salwa; Li, Qi; Randhawa, Parmjeet; Hoffman, Rosemary A; Ramaswami, Balathiripurasundari; Lund, Frances E; Chalasani, Geetha

    2014-03-01

    Chronic rejection is the primary cause of long-term failure of transplanted organs and is often viewed as an antibody-dependent process. Chronic rejection, however, is also observed in mice and humans with no detectable circulating alloantibodies, suggesting that antibody-independent pathways may also contribute to pathogenesis of transplant rejection. Here, we have provided direct evidence that chronic rejection of vascularized heart allografts occurs in the complete absence of antibodies, but requires the presence of B cells. Mice that were deficient for antibodies but not B cells experienced the same chronic allograft vasculopathy (CAV), which is a pathognomonic feature of chronic rejection, as WT mice; however, mice that were deficient for both B cells and antibodies were protected from CAV. B cells contributed to CAV by supporting splenic lymphoid architecture, T cell cytokine production, and infiltration of T cells into graft vessels. In chimeric mice, in which B cells were present but could not present antigen, both T cell responses and CAV were markedly reduced. These findings establish that chronic rejection can occur in the complete absence of antibodies and that B cells contribute to this process by supporting T cell responses through antigen presentation and maintenance of lymphoid architecture.

  4. Influence of biofouling on pharmaceuticals rejection in NF membrane filtration.

    Science.gov (United States)

    Botton, Sabrina; Verliefde, Arne R D; Quach, Nhut T; Cornelissen, Emile R

    2012-11-15

    The effects of biomass attachment and growth on the surface characteristics and organic micropollutants rejection performance of nanofiltration membranes were investigated in a pilot installation. Biomass growth was induced by dosing of a readily biodegradable carbon source resulting in the formation of a biofouling in the investigated membrane elements. Surface properties and rejection behaviour of a biofouled and virgin membrane were investigated and compared in terms of surface charge, surface energy and hydrophobicity. The last two were accomplished by performing contact angle measurements on fully hydrated membrane surfaces, in order to mimic the operating conditions of a membrane in contact with water. Compared to a virgin membrane, deposition and growth of biofilm did slightly alter the surface charge, which became more negative, and resulted in a higher hydrophilicity of the membrane surface. In addition, the presence of the negatively charged biofilm induced accumulation of positively charged pharmaceuticals within the biomass layer, which probably also hindered back diffusion. This caused a reduction in rejection efficiency of positively charged solutes but did not alter rejection of neutral and negatively charged pharmaceuticals. Pharmaceuticals rejection was found to positively correlate with the specific free energy of interaction between virgin or biofouled membranes and pharmaceuticals dissolved in the water phase. The rejection values obtained with both virgin and biofouled membranes were compared and found in good agreement with the predictions calculated with a solute transport model earlier developed for high pressure filtration processes. PMID:22960036

  5. A novel noninvasive method to detect rejection after heart transplantation

    Directory of Open Access Journals (Sweden)

    Jun Hu

    2012-12-01

    Full Text Available Prompt and accurate detection of rejection prior to pathological changes after organ transplantation is vital for monitoring rejections. Although biopsy remains the current gold standard for rejection diagnosis, it is an invasive method and cannot be repeated daily. Thus, noninvasive monitoring methods are needed. In this study, by introducing an IL-2 neutralizing monoclonal antibody (IL-2 N-mAb and immunosuppressants into the culture with the presence of specific stimulators and activated lymphocytes, an activated lymphocyte-specific assay (ALSA system was established to detect the specific activated lymphocytes. This assay demonstrated that the suppression in the ALSA test was closely related to the existence of specific activated lymphocytes. The ALSA test was applied to 47 heart graft recipients and the proliferation of activated lymphocytes from all rejection recipients proven by endomyocardial biopsies was found to be inhibited by spleen cells from the corresponding donors, suggesting that this suppression could reflect the existence of activated lymphocytes against donor antigens, and thus the rejection of a heart graft. The sensitivity of the ALSA test in these 47 heart graft recipients was 100%; however, the specificity was only 37.5%. It was also demonstrated that IL-2 N-mAb was indispensible, and the proper culture time courses and concentrations of stimulators were essential for the ALSA test. This preliminary study with 47 grafts revealed that the ALSA test was a promising noninvasive tool, which could be used in vitro to assist with the diagnosis of rejection post-heart transplantation.

  6. B cells mediate chronic allograft rejection independently of antibody production.

    Science.gov (United States)

    Zeng, Qiang; Ng, Yue-Harn; Singh, Tripti; Jiang, Ke; Sheriff, Khaleefathullah A; Ippolito, Renee; Zahalka, Salwa; Li, Qi; Randhawa, Parmjeet; Hoffman, Rosemary A; Ramaswami, Balathiripurasundari; Lund, Frances E; Chalasani, Geetha

    2014-03-01

    Chronic rejection is the primary cause of long-term failure of transplanted organs and is often viewed as an antibody-dependent process. Chronic rejection, however, is also observed in mice and humans with no detectable circulating alloantibodies, suggesting that antibody-independent pathways may also contribute to pathogenesis of transplant rejection. Here, we have provided direct evidence that chronic rejection of vascularized heart allografts occurs in the complete absence of antibodies, but requires the presence of B cells. Mice that were deficient for antibodies but not B cells experienced the same chronic allograft vasculopathy (CAV), which is a pathognomonic feature of chronic rejection, as WT mice; however, mice that were deficient for both B cells and antibodies were protected from CAV. B cells contributed to CAV by supporting splenic lymphoid architecture, T cell cytokine production, and infiltration of T cells into graft vessels. In chimeric mice, in which B cells were present but could not present antigen, both T cell responses and CAV were markedly reduced. These findings establish that chronic rejection can occur in the complete absence of antibodies and that B cells contribute to this process by supporting T cell responses through antigen presentation and maintenance of lymphoid architecture. PMID:24509079

  7. The private rejection of unfair offers and emotional commitment.

    Science.gov (United States)

    Yamagishi, Toshio; Horita, Yutaka; Takagishi, Haruto; Shinada, Mizuho; Tanida, Shigehito; Cook, Karen S

    2009-07-14

    In a series of experiments, we demonstrate that certain players of an economic game reject unfair offers even when this behavior increases rather than decreases inequity. A substantial proportion (30-40%, compared with 60-70% in the standard ultimatum game) of those who responded rejected unfair offers even when rejection reduced only their own earnings to 0, while not affecting the earnings of the person who proposed the unfair split (in an impunity game). Furthermore, even when the responders were not able to communicate their anger to the proposers by rejecting unfair offers in a private impunity game, a similar rate of rejection was observed. The rejection of unfair offers that increases inequity cannot be explained by the social preference for inequity aversion or reciprocity; however, it does provide support for the model of emotion as a commitment device. In this view, emotions such as anger or moral disgust lead people to disregard the immediate consequences of their behavior, committing them to behave consistently to preserve integrity and maintain a reputation over time as someone who is reliably committed to this behavior. PMID:19564602

  8. Characterization of the Oum El Khacheb phosphorites (South Tunisia) and enrichment of big rejections by grinding

    Institute of Scientific and Technical Information of China (English)

    Mâamri Alimi Jihen; Abbassi Leila; Batis Harrouch Narjes

    2016-01-01

    In the last decade, the phosphate reserves have started to decrease. In this study, both phosphate of Oum El Khacheb’s (O.E.K) region (South of Tunisia) and its big rejections were characterized mineralogically and chemically by several analysis methods such as the binocular magnifying glass, X-rays diffraction technique, Technicon auto-analyzer, atomic absorption spectroscopy, and carbon sulfur analyzer. Then, this work focuses on the coarse rejections of O.E.K’s phosphorites which can be valorized by the wet grinding method. Therefore, we have used the methodology of experimental research to determine the optimal grinding conditions. Results found by Doelhert matrix are: a duration at about 4 min, a pulp on solid concentration of 45.00%, a number of cycles equals to 60 rpm and 3.87 as the jar’s loading. The enhancement of the weight yields of phosphate recuperation increased significantly by 46.39%from big rejections with 24.60%of P2O5 concentration.

  9. Mice aorta loop grafting: A new model which separate vascular rejection and neointimal formation in chronic rejection

    Institute of Scientific and Technical Information of China (English)

    陈勇; 窦科峰; 何勇; 孙凯

    2003-01-01

    Objective: To study the cause and mechanism of transplantation vasculopathy which characterized by accelerated graft arteriosclerosis (AGA), we established a mouse aorta graft model. Methods: A segment of thoracic aortas of B10.A (2R) mice were transplanted to C57BL/10 mice abdominal aorta by end to side anastomoses. The different time point collected grafts were analyzed by morphological, histochemical and electro microscopic methods. Results: Rejection was manifested as a concentric progressive destruction of the smooth muscle cells. In contrast, the endothelial inflammation and subsequent neointimal proliferation characteristic of AGA was localized to the regions of turbulent flow, i.e. the junction of the graft with the recipient aorta. Conclusion: This model separates the processes of rejection and neointimal formation which usually manifested together in the lesion of AGA, elucidate that different mechanisms control vascular rejection and neointimal formation in chronic rejection.

  10. Leaching of cadmium, chromium, copper, lead, and zinc from two slag dumps with different environmental exposure periods under dynamic acidic condition.

    Science.gov (United States)

    Jin, Zhisheng; Liu, Taoze; Yang, Yuangen; Jackson, Daniel

    2014-06-01

    Over the past few decades, zinc smelting activities in Guizhou, China have produced numerous slag dumps, which are often dispersed on roadsides and hill slopes throughout the region. During periods of acid rain, these exposed slags release heavy metals into surface water bodies. A column leaching study was designed to test the potential release of the heavy metals cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn) under simulated acid rain events. Two slags with varying environmental exposure periods were packed in columns and subjected to leaching solutions of pH 3.5, 5.5, or DI H2O at intervals of 1, 7, 14, 28, 56d. Pulse concentrations of Cd in leachate were found above 5μg/L, Cr, Pb, and Zn >10μg/L, whereas, Cu reached 10μg/L. After five leaching events, the leachability (percentage of cumulative heavy metal leached after five leaching events as in its respective total concentration in slags) of Cd was 0.05 percent and 0.035 percent from the old and young slag, respectively. Cr (0.035 percent and 0.05 percent) was greater than Cu (0.002 percent and 0.005 percent) and Zn (0.006 percent and 0.003 percent), while the lowest leachability was observed for Pb (0.0005 percent and 0.0002 percent) from the old and young slags, respectively. Reaction rates (release amount of heavy metals in certain period of leaching) of heavy metals in the leachates demonstrated the sequence of Zn>Cr>Cd, Cu>Pb. Leaching release of heavy metals was jointly affected by the pH of leaching solution and mineral composition of slags (including chemical forms of Cd, Cr, Cu, Pb, and Zn). Environmental exposure period of slags, resulting in the alteration of minerals, could affect the release process of heavy metals in leaching as well. PMID:24632122

  11. Organic ligands influence leaching kinetics of fixated FGD material

    Energy Technology Data Exchange (ETDEWEB)

    Chin-Min Cheng; Yu Sik Hwang; John J. Lenhart; Harold W. Walker [Ohio State University, Columbus, OH (United States). Department of Civil and Environmental Engineering and Geodetic Science

    2008-10-15

    The presence of organic ligands, including oxalate, citrate, maleate and Pahokee peat humic acid (PPHA), influenced the leaching kinetics of fixated flue gas desulfurization (FGD) material in acidic solution (pH 2.9-5.0). In the presence of oxalate, the leaching was inhibited at all pH values examined. XRD and SEM analyses demonstrated that formation of a calcium oxalate mineral phase on the fixated FGD material surface created a surface layer which reduced the extent of leaching. Maleate and PPHA inhibited leaching at pH 2.9, but either promoted, inhibited, or had no effect on leaching, depending on the particular element, at pH 5.0. ATR-FTIR analysis indicated maleate and PPHA formed both inner- and outer-spherically bound species at pH 2.9, whereas at pH 5.0 only outer-sphere complexes seemed evident. These surface species likely inhibited the leaching process at pH 2.9 through a surface blocking mechanism. At pH 5.0, the ligand surface complexes either promoted or inhibited leaching, depending on the element, through a combination of direct and indirect mechanisms. Citrate significantly promoted the leaching process at all pH values examined. 43 refs., 6 figs., 3 tabs.

  12. Leaching of polyphase nuclear waste ceramics: microstructural and phase characterization

    International Nuclear Information System (INIS)

    Alumina-based ceramics are potential materials for storage of nuclear wastes. Static leach tests conducted on ceramic monoliths in deionized water, in simulated silicate, and in brine groundwaters, conforming to Materials Characterization Center standards and an accelerated, microscopic leach test, were used to identify the processes. Dissolution and formation of surface passivation layers are discussed. 40 refs

  13. Nitrate leaching and pesticide use in energy crops

    DEFF Research Database (Denmark)

    Jørgensen, Uffe

    2006-01-01

    Nitrate leaching measured below willow and miscanthus is very low from the established crops. Pesticide use in energy crops is low as well.......Nitrate leaching measured below willow and miscanthus is very low from the established crops. Pesticide use in energy crops is low as well....

  14. Accelerated Leach Test(s) Program: Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Dougherty, D.R.; Pietrzak, R.F.; Fuhrmann, M.; Colombo, P.

    1986-09-01

    A computerized data base of LLW leaching data has been developed. Long-term tests on portland cement, bitumen and vinyl ester-styrene (VES) polymer waste forms containing simulated wastes are underway which are designed to identify and evaluate factors that accelerate leaching without changing the mechanisms.

  15. Pesticide leaching in macroporous clay soils: field experiment and modeling

    NARCIS (Netherlands)

    Scorza Júnior, R.P.

    2002-01-01

    Keywords : pesticide leaching, macropores, preferential flow, preferential transport, cracked clay soil, pesticide leaching models, groundwater contamination, inverse modeling, bentazone and imidacloprid. The presence of macropores (i.e. shrinkage c

  16. Water flow and nitrate leaching in a layered silt loam

    NARCIS (Netherlands)

    Vos, J.A.; Hesterberg, D.L.R.; Raats, P.A.C.

    2000-01-01

    Nitrate (NO3) leaching was studied for a winter leaching period in a layered calcareous silt loam with tile-drains at about 1-m depth and 12-m spacing. Groundwater levels, drain discharge rates, and NO3 concentrations in the drainage water were monitored, and the soil hydraulic characteristics were

  17. PLEASE: a simple model to determine P losses by leaching

    NARCIS (Netherlands)

    Schoumans, O.F.; Salm, van der C.; Groenendijk, P.

    2013-01-01

    Non-point phosphorus (P) loss from agricultural land to streams is caused mainly by overland flow and leaching. In many countries P-index methods are used to identify areas at risk of P loss to streams. In flat areas with shallow groundwater levels, where losses by leaching are important, these inde

  18. Leaching characteristics of paraffin waste package with pinhole

    International Nuclear Information System (INIS)

    An Effect of pinhole(perforation or pit penetration) that might be formed outside the package on the nuclide leaching from paraffin waste form was investigated. In case of single pinhole, the leached mass and cumulative fraction leached (CFL) increased with the larger diameter of pinhole, but they were not in direct proportion to the size or area of pinhole. If the total area of multiple pinholes was fixed, the leached mass showed a tendency to increase as each size was smaller and the number was more. It was also found that the leached mass was not in direct proportion to the number of pinhole in case of constant size. In order to analyze the test results, the shrinking core model(SCM) was derived from the diffusion-controlled dissolution reaction and compared with previous diffusion model

  19. COMPILATION OF LABORATORY SCALE ALUMINUM WASH AND LEACH REPORT RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    HARRINGTON SJ

    2011-01-06

    This report compiles and analyzes all known wash and caustic leach laboratory studies. As further data is produced, this report will be updated. Included are aluminum mineralogical analysis results as well as a summation of the wash and leach procedures and results. Of the 177 underground storage tanks at Hanford, information was only available for five individual double-shell tanks, forty-one individual single-shell tanks (e.g. thirty-nine 100 series and two 200 series tanks), and twelve grouped tank wastes. Seven of the individual single-shell tank studies provided data for the percent of aluminum removal as a function of time for various caustic concentrations and leaching temperatures. It was determined that in most cases increased leaching temperature, caustic concentration, and leaching time leads to increased dissolution of leachable aluminum solids.

  20. COMPILATION OF LABORATORY SCALE ALUMINUM WASH AND LEACH REPORT RESULTS

    International Nuclear Information System (INIS)

    This report compiles and analyzes all known wash and caustic leach laboratory studies. As further data is produced, this report will be updated. Included are aluminum mineralogical analysis results as well as a summation of the wash and leach procedures and results. Of the 177 underground storage tanks at Hanford, information was only available for five individual double-shell tanks, forty-one individual single-shell tanks (e.g. thirty-nine 100 series and two 200 series tanks), and twelve grouped tank wastes. Seven of the individual single-shell tank studies provided data for the percent of aluminum removal as a function of time for various caustic concentrations and leaching temperatures. It was determined that in most cases increased leaching temperature, caustic concentration, and leaching time leads to increased dissolution of leachable aluminum solids.

  1. 一种LEACH协议的改进算法LEACH_EH%An improved algorithm of LEACH protocol LEACH-EH

    Institute of Scientific and Technical Information of China (English)

    徐鹏

    2014-01-01

    根据 LEACH 协议的特点和局限性对其进行了改进,提出了一种 LEACH_EH ( LEACH EAHANCE )算法。它使用 K_MEANS 算法对簇进行一次性分簇,之后结合节点到簇内质心距离与节点自身剩余能量选举出簇头。它将簇形成的顺序由先簇头后成簇变为先成簇后簇头,形成一次分簇多次选举簇头的模式。通过 MATLAB 进行仿真,实验结果表明,改进后的算法比原来的协议在节点能量均衡方面有了较大的提升,延长了网络生存周期。%This paper propose a LEACH_EH algorithm based on the characteristics and limitations of the LEACH protocol.It uses the K_MEANS algorithm to cluster only once, and then elects the cluster heads by considersing the distance from node to cluster center and the node′s residual energy. It makes the order from electing cluster first and clustering second to clustering first and electing cluster second. It forms the formation of clustering only once and electing cluster multi-times. The MATLAB simulation shows that comparing with LEACH, the LEACH_ED algorithm has a great improvement in the energy balance of the node,and prolong the network life cycle abviously.

  2. SULPHUR DIOXIDE LEACHING OF URANIUM CONTAINING MATERIAL

    Science.gov (United States)

    Thunaes, A.; Rabbits, F.T.; Hester, K.D.; Smith, H.W.

    1958-12-01

    A process is described for extracting uranlum from uranium containing material, such as a low grade pitchblende ore, or mill taillngs, where at least part of the uraniunn is in the +4 oxidation state. After comminuting and magnetically removing any entrained lron particles the general material is made up as an aqueous slurry containing added ferric and manganese salts and treated with sulfur dioxide and aeration to an extent sufficient to form a proportion of oxysulfur acids to give a pH of about 1 to 2 but insufficient to cause excessive removal of the sulfur dioxide gas. After separating from the solids, the leach solution is adjusted to a pH of about 1.25, then treated with metallic iron in the presence of a precipitant such as a soluble phosphate, arsonate, or fluoride.

  3. Long-term leaching from MSWI air-pollution-control residues: Leaching characterization and modeling

    DEFF Research Database (Denmark)

    Hyks, Jiri; Astrup, Thomas; Christensen, Thomas Højlund

    2009-01-01

    Long-term leaching of Ca, Fe, Mg, K, Na, S, Al, As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Zn, Mo, Sb, Si, Sri, Sr, Ti, V, P, Cl, and dissolved organic carbon from two different municipal solid waste incineration (MSWI) air-pollution-control residues was monitored during 24 months of column...... percolation experiments; liquid-to-solid (L/S) ratios of 200-250 L/kg corresponding to more than 10,000 years in a conventional landfill were reached. Less than 2% of the initially present As, Cu, Pb, Zn, Cr, and Sb had leached during the Course of the experiments. Concentrations of Cd, Fe, Mg, Hg, Mn, Ni, Co...

  4. Life cycle assessment and residue leaching: The importance of parameter, scenario and leaching data selection

    DEFF Research Database (Denmark)

    Allegrini, Elisa; Butera, Stefania; Kosson, D.S.;

    2015-01-01

    , due to the potential leaching of toxic substances. In waste LCA studies where residue utilisation is included, leaching has generally been neglected. In this study, municipal solid waste incineration bottom ash (MSWI BA) was used as a case study into three LCA scenarios having different system......Residues from industrial processes and waste management systems (WMSs) have been increasingly reutilised, leading to landfilling rate reductions and the optimisation of mineral resource utilisation in society. Life cycle assessment (LCA) is a holistic methodology allowing for the analysis...... of systems and products and can be applied to waste management systems to identify environmental benefits and critical aspects thereof. From an LCA perspective, residue utilisation provides benefits such as avoiding the production and depletion of primary materials, but it can lead to environmental burdens...

  5. INTRATHYMIC INOCULATION OF LIVER SPECIFIC ANTIGEN ALLEVIATES LIVER TRANSPLANT REJECTION

    Institute of Scientific and Technical Information of China (English)

    贾长库; 郑树森; 朱有法

    2004-01-01

    Objective To study the effects of liver specific antigen (LSA) on liver allotransplantation rejection. Methods Orthotopic liver transplantation was performed in this study. Group Ⅰ: syngeneic control (Wistar-to-Wistar); Group Ⅱ: acute rejection (SD-to-Wistar). Group Ⅲ: thymic inoculation of SD rat LSA day 7 before transplantation. The observation of general condition and survival time, rejection grades and the NF-κB activity of splenocytes were used to analyze severity of acute rejection and immune state of animals in different groups. Results The general condition of group Ⅰ was fair post transplantation with no sign of rejection. All recipients of group Ⅱ died within days 9 to 13 post transplantation with median survival time of 10.7 ±1.37 days. As for group Ⅲ, 5 out of 6 recipients survived for a long period with remarkably better general condition than that of group Ⅱ. Its rejection grades were significantly lower than group Ⅱ (P< 0.05).NF-κB activity was only detected in group Ⅰ between days 5 and 7 after transplantation, whereas high activity of NF-κB was detected at all points in group Ⅱ and low NF-κB activity was detected in group Ⅲ which was significantly lower than that of group Ⅱ (P < 0.05). Conclusions LSA is an important transplantation antigen directly involved in the immunorejection of liver transplantation. Intrathymic inoculation of LSA can alleviate the rejection of liver allotransplantation,grafts survive for a period of time thereby, allowing a novel way to liver transplantation immunotolerance.

  6. Using applicative software and software tools for the performance of leaching and bio-leaching

    OpenAIRE

    Krstev, Boris; Krstev, Aleksandar; Gocev, Zivko; Zdravev, Zoran; Krstev, Dejan; Zivanovic, Jordan

    2013-01-01

    The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the mean time, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer program Multisimplex performances are appropriate and most acceptable and exce...

  7. The principles and examples of leaching and bio-leaching using SImplex EVOP

    OpenAIRE

    Krstev, Aleksandar; Krstev, Boris

    2014-01-01

    The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the meantime, investigations are directed to the new possibilities of leaching by microorganisms - bioleaching. The paper is result of these technologies and investigations earned out for recovery of in the mentioned ores. Using Simples EVOP and computer program Multisimplex performances are appropriate and most acceptable and excellen...

  8. The presentation of leaching and bio-leaching from different ores using SIMPLEX EVOP

    OpenAIRE

    Krstev, Boris; Krstev, Aleksandar; Golomeova, Mirjana; Gocev, Zivko

    2013-01-01

    The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the mean time, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer program Multisimplex performances are appropriate and most acceptable and exce...

  9. The performance of leaching and bio-leaching from sulphide ores usiing SEVOP

    OpenAIRE

    Krstev, Boris; Krstev, Aleksandar; Golomeov, Blagoj; Golomeova, Mirjana; Sala, Ferat; Gocev, Zivko; Zivanovic, Jordan; Krstev, Dejan

    2013-01-01

    The refractory or low grade copper chalcopyrite ores or galena/sphalerite domestic ores in Republic of Macedonia are investigated by conventional copper flotation and selective flotation for galena/sphalerite. In the meantime, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer programme. Multisimple...

  10. 6 Million Americans Drink Water Tainted with Toxic Chemicals

    Science.gov (United States)

    ... has its own problems, such as chemicals from plastic bottles leaching into the water. The report was ... looked at about 600 teens from the Faroe Islands, an island country off the coast of Denmark. ...

  11. Leaching of glyphosate and AMPA under two soil management practices in Burgundy vineyards (Vosne-Romanee, 21-France)

    International Nuclear Information System (INIS)

    Some drinking water reservoirs under the vineyards of Burgundy are contaminated with herbicides. Thus the effectiveness of alternative soil management practices, such as grass cover, for reducing the leaching of glyphosate and its metabolite, AMPA, through soils was studied. The leaching of both molecules was studied in structured soil columns under outdoor conditions for 1 year. The soil was managed under two vineyard soil practices: a chemically treated bare calcosol, and a vegetated calcosol. After 680 mm of rainfall, the vegetated calcosol leachates contained lower amounts of glyphosate and AMPA (0.02% and 0.03%, respectively) than the bare calcosol leachates (0.06% and 0.15%, respectively). No glyphosate and only low amounts of AMPA (<0.01%) were extracted from the soil. Glyphosate, and to a greater extent, AMPA, leach through the soils; thus, both molecules may be potential contaminants of groundwater. However, the alternative soil management practice of grass cover could reduce groundwater contamination by the pesticide. - Glyphosate and AMPA leached in greater amounts through a chemically treated bare calcosol than through a vegetated calcosol

  12. Pesticide leaching through sandy and loamy fields e Long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme

    DEFF Research Database (Denmark)

    Rosenbom, Annette Elisabeth; Olsen, Preben; Plauborg, Finn;

    2015-01-01

    The European Union authorization procedure for pesticides includes assessment of the leaching risk posed by pesticides and their degradation products aimed at avoiding any unacceptable influence on the environment, in particular contamination of water, including drinking water and groundwater. The...... procedure has shortcomings, however, as revealed by the past 11years of monitoring results from the Danish Pesticide Leaching Assessment Programme. This monitoring programme have assessed leaching to the groundwater via the variably saturated zone of 43 pesticides applied in accordance with current...... regulations on sandy and loamy agricultural fields, as well as 47 of their degradation products. Three types of leaching scenario were not fully captured by the authorization procedure: i) long-term leaching of degradation products of pesticides applied to potatoes crops cultivated on sandy soils; ii...

  13. Aid-Leaching Reagent of Leaching Scandium from Scandium Concentrate in Complex Silicate%复杂硅酸盐含钪精矿钪浸出助浸剂试验研究

    Institute of Scientific and Technical Information of China (English)

    谭俊峰; 张桂芳; 张昱; 张宗华

    2012-01-01

    Chemical analysis and determination of scandium phase on complex silicate ore with scandium were studied. The concentrate leaching help infusions were studied on the basis of scandium separation from complex of silicate mineral, so as to find proper leaching solution and the appropriate help infusion to concentrate the useful ions, but to retain harmful ion for leaching concentrate in leaching reside. In this sample, scandium distributed as isomorphs in many kinds of complex of silicate minerals. Silicate minerals were obtained by using hydrochloric acid leaching and the scandium element was leached in hydrochloric acid solution. Leaching help infusions was one of the major factor of scandium leaching rate. On the basis of hydrochloric acid as leaching agent, aid-leaching reagents such as the sorts and amount of leaching teaching reagent, ratio of liquid to solid, leaching time, concentration of hydrochloric acid, leaching temperature, and particle size of ore were studied. Optimum leaching conditions were obtained. The results showed that; (1) the sample contained numerous complicated ingredients and impurity ions, including the lively metal ions, calcium element and magnesium ions impurity ions that had a great influence on leaching. (2) The best scandium leaching results could be produced by using HC1 and No. 2 aid-leaching reagent together, the optimum experimental conditions were that particle size of ore was -0.05 mm, quality score of HC1 was IS. 2% , ratio of liquid to solid was 5:1, dosage of No. 2 aid-leaching reagent was 4%. Leaching temperature was 90 X., leaching time was 12 h and leaching rate of scandium was 88. 33%.%对复杂硅酸盐含钪矿进行了化学成分分析,钪物相的测定等的研究.研究是在复杂硅酸盐类矿物选钪试验的基础上,进行复杂硅酸盐含钪精矿浸出助浸剂试验研究,通过试验研究找到了合适的浸出液和适当的助浸剂,对有用离子进行浸出富集,对有害的离子使其保留

  14. Kinetics of Mo, Ni, V and Al leaching from a spent hydrodesulphurization catalyst in a solution containing oxalic acid and hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Szymczycha-Madeja, Anna, E-mail: anna.szymczycha@pwr.wroc.pl [Chemistry Department, Analytical Chemistry Division, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland)

    2011-02-28

    The kinetics of molybdenum, nickel, vanadium and aluminium leaching from a spent hydrodesulphurization catalyst in a solution containing oxalic acid and hydrogen peroxide was investigated. The effects of temperature and particle size were examined. In addition, the reaction mechanism for the dissolution of the spent catalyst was discussed. The results of the kinetic analysis for various experimental conditions indicated that the reaction rate of leaching process is controlled by chemical reaction at the particle surface. The values of the activation energies of 31 {+-} 2, 36 {+-} 4, 30 {+-} 4 and 57 {+-} 3 kJ mol{sup -1} for Mo, Ni, V and Al, respectively, are characteristic for mechanism controlled by chemical reaction.

  15. Tight ceramic UF membrane as RO pre-treatment: the role of electrostatic interactions on phosphate rejection.

    Science.gov (United States)

    Shang, Ran; Verliefde, Arne R D; Hu, Jingyi; Zeng, Zheyi; Lu, Jie; Kemperman, Antoine J B; Deng, Huiping; Nijmeijer, Kitty; Heijman, Sebastiaan G J; Rietveld, Luuk C

    2014-01-01

    Phosphate limitation has been reported as an effective approach to inhibit biofouling in reverse osmosis (RO) systems for water purification. The rejection of dissolved phosphate by negatively charged TiO2 tight ultrafiltration (UF) membranes (1 kDa and 3 kDa) was observed. These membranes can potentially be adopted as an effective process for RO pre-treatment in order to constrain biofouling by phosphate limitation. This paper focuses on electrostatic interactions during tight UF filtration. Despite the larger pore size, the 3 kDa ceramic membrane exhibited greater phosphate rejection than the 1 kDa membrane, because the 3 kDa membrane has a greater negative surface charge and thus greater electrostatic repulsion against phosphate. The increase of pH from 6 to 8.5 led to a substantial increase in phosphate rejection by both membranes due to increased electrostatic repulsion. At pH 8.5, the maximum phosphate rejections achieved by the 1 kDa and 3 kDa membrane were 75% and 86%, respectively. A Debye ratio (ratio of the Debye length to the pore radius) is introduced in order to evaluate double layer overlapping in tight UF membranes. Threshold Debye ratios were determined as 2 and 1 for the 1 kDa and 3 kDa membranes, respectively. A Debye ratio below the threshold Debye ratio leads to dramatically decreased phosphate rejection by tight UF membranes. The phosphate rejection by the tight UF, in combination with chemical phosphate removal by coagulation, might accomplish phosphate-limited conditions for biological growth and thus prevent biofouling in the RO systems.

  16. The composition of the microbiota modulates allograft rejection.

    Science.gov (United States)

    Lei, Yuk Man; Chen, Luqiu; Wang, Ying; Stefka, Andrew T; Molinero, Luciana L; Theriault, Betty; Aquino-Michaels, Keston; Sivan, Ayelet S; Nagler, Cathryn R; Gajewski, Thomas F; Chong, Anita S; Bartman, Caroline; Alegre, Maria-Luisa

    2016-07-01

    Transplantation is the only cure for end-stage organ failure, but without immunosuppression, T cells rapidly reject allografts. While genetic disparities between donor and recipient are major determinants of the kinetics of transplant rejection, little is known about the contribution of environmental factors. Because colonized organs have worse transplant outcome than sterile organs, we tested the influence of host and donor microbiota on skin transplant rejection. Compared with untreated conventional mice, pretreatment of donors and recipients with broad-spectrum antibiotics (Abx) or use of germ-free (GF) donors and recipients resulted in prolonged survival of minor antigen-mismatched skin grafts. Increased graft survival correlated with reduced type I IFN signaling in antigen-presenting cells (APCs) and decreased priming of alloreactive T cells. Colonization of GF mice with fecal material from untreated conventional mice, but not from Abx-pretreated mice, enhanced the ability of APCs to prime alloreactive T cells and accelerated graft rejection, suggesting that alloimmunity is modulated by the composition of microbiota rather than the quantity of bacteria. Abx pretreatment of conventional mice also delayed rejection of major antigen-mismatched skin and MHC class II-mismatched cardiac allografts. This study demonstrates that Abx pretreatment prolongs graft survival, suggesting that targeting microbial constituents is a potential therapeutic strategy for enhancing graft acceptance.

  17. Gene Expression Profiling on Acute Rejected Transplant Kidneys with Microarray

    Institute of Scientific and Technical Information of China (English)

    Deping LI; Kang WANG; Yong DAI; Tianyu LV

    2008-01-01

    To investigate the gene expression profiles in acute allograft rejection of renal trans- plantation, and identify the markers for the early diagnosis of acute rejection, heterotopic kidney transplantation was performed by using F344 or Lewis donors and Lewis recipients. No immunosup- pressant was used. Renal grafts were harvested on days 3, 7, and 14. A commercial microarray was used to measure gene expression levels in day-7 grafts. The expression levels of 48 genes were up-regulated in the allograft in comparison with the isograft control, and interferon-y-induced GTPase gene was most significantly up-regulated in allografts. It is concluded that a variety of pathways are involved in organ transplant rejection which is dynamic and non-balanced. IFN-inducible genes, such as IGTP, may play an important role in the rejection. A lot of important factors involved in acute re- jection are unnecessary but sufficient conditions for the rejection. We are led to conclude that it is virtually impossible to make an early diagnosis based on a single gene marker, but it could he achieved on the basis of a set of markers.

  18. The composition of the microbiota modulates allograft rejection.

    Science.gov (United States)

    Lei, Yuk Man; Chen, Luqiu; Wang, Ying; Stefka, Andrew T; Molinero, Luciana L; Theriault, Betty; Aquino-Michaels, Keston; Sivan, Ayelet S; Nagler, Cathryn R; Gajewski, Thomas F; Chong, Anita S; Bartman, Caroline; Alegre, Maria-Luisa

    2016-07-01

    Transplantation is the only cure for end-stage organ failure, but without immunosuppression, T cells rapidly reject allografts. While genetic disparities between donor and recipient are major determinants of the kinetics of transplant rejection, little is known about the contribution of environmental factors. Because colonized organs have worse transplant outcome than sterile organs, we tested the influence of host and donor microbiota on skin transplant rejection. Compared with untreated conventional mice, pretreatment of donors and recipients with broad-spectrum antibiotics (Abx) or use of germ-free (GF) donors and recipients resulted in prolonged survival of minor antigen-mismatched skin grafts. Increased graft survival correlated with reduced type I IFN signaling in antigen-presenting cells (APCs) and decreased priming of alloreactive T cells. Colonization of GF mice with fecal material from untreated conventional mice, but not from Abx-pretreated mice, enhanced the ability of APCs to prime alloreactive T cells and accelerated graft rejection, suggesting that alloimmunity is modulated by the composition of microbiota rather than the quantity of bacteria. Abx pretreatment of conventional mice also delayed rejection of major antigen-mismatched skin and MHC class II-mismatched cardiac allografts. This study demonstrates that Abx pretreatment prolongs graft survival, suggesting that targeting microbial constituents is a potential therapeutic strategy for enhancing graft acceptance. PMID:27322054

  19. Ipsilateral Lymphadenectomy to Inhibit Corneal Allograft Rejection in Rats

    Institute of Scientific and Technical Information of China (English)

    LING Shiqi; HU Yanhua

    2005-01-01

    In order to investigate the ipsilateral lymphadenectomy for inhibiting rejection in rat corneal transplantation, corneal allogenic transplantation models were established in rats. Eighteen female Wister rats were used as donors, and 36 Sprague Dawley rats as recipients. After penetrating corneal transplantation, recipients were randomly divided into 3 groups: group A (control group);group B, the ipsilateral lymphadenectomy group; group C, the bilateral lymphadenectomy group.Among 12 rats in each group, the corneas of 2 rats in each group were used for pathological study at day 14 after the transplantation, and the remaining 10 rats were used for studying corneal rejection by a slit lamp. The time points when allograft rejection occurred were recorded and mean survival time (MST) was compared. The results showed that MST in groups B and C was 46.30±9.464 days and 44.43 ± 7. 604 days, respectively, which was significantly prolonged as compared with that in group A (10.71±1. 567 days, P<0.01). There was no significant difference in MST between groups B and C (P>0.05). Itwas concluded that both bilateral and ipsilateral lymphadenectomy therapies could effectively inhibit the corneal allograft rejection. Ipsilateral lymphadenectomy is a less complex surgical procedure and is just as effective in preventing rejection.

  20. Biochar amendment affects leaching potential of copper and nutrient release behavior in contaminated sandy soils.

    Science.gov (United States)

    Bakshi, Santanu; He, Zhenli L; Harris, Willie G

    2014-11-01

    Copper (Cu) contamination to soil and water is a worldwide concern. Biochar has been suggested to remediate degraded soils. In this study, column leaching and chemical characterization were conducted to assess effects of biochar amendment on Cu immobilization and subsequent nutrient release in Cu-contaminated Alfisol and Spodosol. The results indicate that biochar is effective in binding Cu (30 and 41%, respectively, for Alfisol with and without spiked Cu; 36 and 43% for Spodosol) and reducing Cu leaching loss (from ∼47 to 10% for the Cu-spiked Alfisol and from 48 to 9% for the Cu-spiked Spodosol). Copper was likely retained on biochar surfaces through complexation, as suggested by Fourier-transform infrared spectra. Biochar amendment converts a portion of Cu from available pool to more stable forms, thus resulting in decreased activities of free Cu and increased activity of organic Cu complexes in leachate. Reduction of >0.45-μm solids and nanoparticles concentrations in leachate was also observed. In addition, biochar application rate was correlated negatively with P, Ca, Mg, Zn, Mn, and NH-N concentration ( < 0.05) but positively with K and Na concentration ( < 0.05) in leachates. These results documented the potential of biochar as an effective amendment for Cu immobilization and mitigation of leaching risk for some nutrients. PMID:25602206

  1. Leaching of asbestos-cement cooling-tower fill. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, C.N.; Stone, R.W.

    1981-04-01

    Cooling-tower fill is sometimes made of asbestos cement. Asbestos-cement fill has frequently been damaged by leaching and mechanical problems. This leaching was investigated. Previous studies of asbestos-cement water pipe and cooling-tower fill are summarized. Five plants were visited, and 43 others were contacted by telephone. Water and fill samples were collected and analyzed. About half of the cooling towers with asbestos-cement fill have experienced significant deterioration. To control leaching, water should not be undersaturated with respect to calcium carbonate. The Langelier saturation index is a useful tool for controlling blowdown rates and chemical feed. However, because this index does not allow for all of the relevant factors, it is not possible to recommend values that are suitable for all plants. If no scale inhibitors are used, the index should be kept as high as possible without causing calcium carbonate scale. If scale inhibitors are used, overdosing should be avoided. Asbestos-cement fill should be used only if the cooling-water chemistry can be well controlled. Specifications for asbestos-cement fill can be improved. Other design features, operating practices, and research are suggested.

  2. Vanadium recovery from clay vanadium mineral using an acid leaching method

    Institute of Scientific and Technical Information of China (English)

    LI Haoran; FENG Yali; LIANG Jianglong; LUO Xiaobing; DU Zhuwei

    2008-01-01

    A technique including direct acid leaching,vanadium precipitation with alkaline,sodium hydroxide releaching,impurity removing by adjusting pH value,precipitation vanadium with ammonium chloride,and vanadium pentoxide by roasting steps was proposed according to the characteristic of Xichuan clay vanadium mineral.The factors influencing leaching vanadium such as temperature and the concentration of sulfuric acid were investigated and optimized.The experimental results indicate that the extract ratios of V2O5 can reach 94% and 92% at a sodium chlorate ratio of 3% and a manganese dioxide ratio of 3%,respectively.A completely chemical precipitation method was adopted to decontaminate and enrich the vanadium in the acid leaching solution.The X-ray diffraction (XRD) pattern and the purity analysis of vanadium pentoxide indicate that the purity of final vanadium pentoxide can reach 99% and meet the standard specifications.The total recovery can reach about 75%.The technique has the characteristics of simplicity,less investlnent,and more environment safety as compared with the traditional salt roasting method.

  3. Characterization, Leaching, and Filtration Testing for Tributyl Phosphate (TBP, Group 7) Actual Waste Sample Composites

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Matthew K.; Billing, Justin M.; Blanchard, David L.; Buck, Edgar C.; Casella, Amanda J.; Casella, Andrew M.; Crum, J. V.; Daniel, Richard C.; Draper, Kathryn E.; Fiskum, Sandra K.; Jagoda, Lynette K.; Jenson, Evan D.; Kozelisky, Anne E.; MacFarlan, Paul J.; Peterson, Reid A.; Shimskey, Rick W.; Snow, Lanee A.; Swoboda, Robert G.

    2009-03-09

    .A testing program evaluating actual tank waste was developed in response to Task 4 from the M-12 External Flowsheet Review Team (EFRT) issue response plan. The bulk water-insoluble solid wastes that are anticipated to be delivered to the Waste Treatment and Immobilization Plant (WTP) were identified according to type such that the actual waste testing could be targeted to the relevant categories. Eight broad waste groupings were defined. Samples available from the 222S archive were identified and obtained for testing. The actual waste-testing program included homogenizing the samples by group, characterizing the solids and aqueous phases, and performing parametric leaching tests. The tributyl phosphate sludge (TBP, Group 7) is the subject of this report. The Group 7 waste was anticipated to be high in phosphorus as well as aluminum in the form of gibbsite. Both are believed to exist in sufficient quantities in the Group 7 waste to address leaching behavior. Thus, the focus of the Group 7 testing was on the removal of both P and Al. The waste-type definition, archived sample conditions, homogenization activities, characterization (physical, chemical, radioisotope, and crystal habit), and caustic leaching behavior as functions of time, temperature, and hydroxide concentration are discussed in this report. Testing was conducted according to TP-RPP-WTP-467.

  4. Field-scale evaluation of water fluxes and manure solution leaching in feedlot pen soils.

    Science.gov (United States)

    García, Ana R; Maisonnave, Roberto; Massobrio, Marcelo J; Fabrizio de Iorio, Alicia R

    2012-01-01

    Accumulation of beef cattle manure on feedlot pen surfaces generates large amounts of dissolved solutes that can be mobilized by water fluxes, affecting surface and groundwater quality. Our objective was to examine the long-term impacts of a beef cattle feeding operation on water fluxes and manure leaching in feedlot pens located on sandy loam soils of the subhumid Sandy Pampa region in Argentina. Bulk density, gravimetric moisture content, and chloride concentration were quantified. Rain simulation trials were performed to estimate infiltration and runoff rates. Using chloride ion as a tracer, profile analysis techniques were applied to estimate the soil moisture flux and manure conservative chemical components leaching rates. An organic stratum was found over the surface of the pen soil, separated from the underlying soil by a highly compacted thin layer (the manure-soil interface). The soil beneath the organic layer showed greater bulk density in the A horizon than in the control soil and had greater moisture content. Greater concentrations of chloride were found as a consequence of the partial sealing of the manure-soil interface. Surface runoff was the dominant process in the feedlot pen soil, whereas infiltration was the main process in control soil. Soil moisture flux beneath pens decreased substantially after 15 yr of activity. The estimated minimum leaching rate of chloride was 13 times faster than the estimated soil moisture flux. This difference suggests that chloride ions are not exclusively transported by advective flow under our conditions but also by solute diffusion and preferential flow. PMID:23099951

  5. Application of Anova on Fly Ash Leaching Kinetics for Value Addition

    Science.gov (United States)

    Swain, Ranjita; Mohapatro, Rudra Narayana; Bhima Rao, Raghupatruni

    2016-04-01

    Fly ash is a major problem in power plant sectors as it is dumped at the plant site. Fly ash generation increases day to day due to rapid growth of steel industries. Ceramic/refractory industries are growing rapidly because of more number of steel industries. The natural resources of the ceramic/refractory raw materials are depleting with time due to its consumption. In view of this, fly ash from thermal power plant has been identified for use in the ceramic/refractory industries after suitable beneficiation. In this paper, sample was collected from the ash pond of Vedanta. Particle size (d80 passing size) of the sample is around 150 micron. The chemical analysis of the sample shows that 3.9 % of Fe2O3 and CaO is more than 10 %. XRD patterns show that the fly ash samples consist predominantly of the crystalline phases of quartz, hematite and magnetite in a matrix of aluminosilicate glass. Leaching of iron oxide is 98.3 % at 3 M HCl concentration at 90 °C for 270 min of leaching time. Kinetic study on leaching experiment was carried out. ANOVA software is utilized for curve fitting and the process is optimized using MATLAB 7.1. The detailed study of properties for ceramic material is compared with the standard ceramic materials. The product contains 0.3 % of iron. The other properties of the product have established the fact that the product obtained can be a raw material for ceramic industries.

  6. Simultaneous application of dissolution/precipitation and surface complexation/surface precipitation modeling to contaminant leaching.

    Science.gov (United States)

    Apul, Defne S; Gardner, Kevin H; Eighmy, T Taylor; Fällman, Ann-Marie; Comans, Rob N J

    2005-08-01

    This paper discusses the modeling of anion and cation leaching from complex matrixes such as weathered steel slag. The novelty of the method is its simultaneous application of the theoretical models for solubility, competitive sorption, and surface precipitation phenomena to a complex system. Selective chemical extractions, pH dependent leaching experiments, and geochemical modeling were used to investigate the thermodynamic equilibrium of 12 ions (As, Ca, Cr, Ba, SO4, Mg, Cd, Cu, Mo, Pb, V, and Zn) with aqueous complexes, soluble solids, and sorptive surfaces in the presence of 12 background analytes (Al, Cl, Co, Fe, K, Mn, Na, Ni, Hg, NO3, CO3, and Ba). Modeling results show that surface complexation and surface precipitation reactions limit the aqueous concentrations of Cd, Zn, and Pb in an environment where Ca, Mg, Si, and CO3 dissolve from soluble solids and compete for sorption sites. The leaching of SO4, Cr, As, Si, Ca, and Mg appears to be controlled by corresponding soluble solids. PMID:16124310

  7. Nitrogen fertilizer (15N leaching in a central pivot fertigated coffee crop

    Directory of Open Access Journals (Sweden)

    Rafael Pivotto Bortolotto

    2012-08-01

    Full Text Available Nitrogen has a complex dynamics in the soil-plant-atmosphere system. N fertilizers are subject to chemical and microbial transformations in soils that can result in significant losses. Considering the cost of fertilizers, the adoption of good management practices like fertigation could improve the N use efficiency by crops. Water balances (WB were applied to evaluate fertilizer N leaching using 15N labeled urea in west Bahia, Brazil. Three scenarios (2008/2009 were established: i rainfall + irrigation the full year, ii rainfall only; and iii rainfall + irrigation only in the dry season. The water excess was considered equal to the deep drainage for the very flat area (runoff = 0 with a water table located several meters below soil surface (capillary rise = 0. The control volume for water balance calculations was the 0 - 1 m soil layer, considering that it involves the active root system. The water drained below 1 m was used to estimate fertilizer N leaching losses. WB calculations used the mathematic model of Penman-Monteith for evapotranspiration, considering the crop coefficient equal to unity. The high N application rate associated to the high rainfall plus irrigation was found to be the main cause for leaching, which values were 14.7 and 104.5 kg ha-1 for the rates 400 and 800 kg ha-1 of N, corresponding to 3.7 and 13.1 % of the applied fertilizer, respectively.

  8. The mechanisms of pyrite oxidation and leaching: A fundamental perspective

    Science.gov (United States)

    Chandra, A. P.; Gerson, A. R.

    2010-09-01

    Pyrite is the earth's most abundant sulfide mineral. Its frequent undesirable association with minerals of economic value such as sphalerite, chalcopyrite and galena, and precious metals such as gold necessitates costly separation processes such as leaching and flotation. Additionally pyrite oxidation is a major contributor to the environmental problem of acid rock drainage. The surface oxidation reactions of pyrite are therefore important both economically and environmentally. Significant variations in electrical properties resulting from lattice substitution of minor and trace elements into the lattice structure exist between pyrite from different geographical locations. Furthermore the presence of low coordination surface sites as a result of conchoidal fracture causes a reduction in the band gap at the surface compared to the bulk thus adding further electrochemical variability. Given the now general acceptance after decades of research that electrochemistry dominates the oxidation process, the geographical location, elemental composition and semi-conductor type (n or p) of pyrite are important considerations. Aqueous pyrite oxidation results in the production of sulfate and ferrous iron. However other products such as elemental sulfur, polysulfides, hydrogen sulfide, ferric hydroxide, iron oxide and iron(III) oxyhydroxide may also form. Intermediate species such as thiosulfate, sulfite and polythionates are also proposed to occur. Oxidation and leach rates are generally influenced by solution Eh, pH, oxidant type and concentration, hydrodynamics, grain size and surface area in relation to solution volume, temperature and pressure. Of these, solution Eh is most critical as expected for an electrochemically controlled process, and directly correlates with surface area normalised rates. Studies using mixed mineral systems further indicate the importance of electrochemical processes during the oxidation process. Spatially resolved surface characterisation of fresh

  9. Acidic leaching of copper and tin from used consumer equipment

    Directory of Open Access Journals (Sweden)

    Orac D.

    2015-01-01

    Full Text Available This work is focused on studying thermal pretreatment and leaching of copper and tin from printed circuit boards (PCBs from used consumer equipment. Thermal treatment experiments were realized with and without presence of oxygen at 300°C, 500°C, 700°C and 900°C for 30 minutes. Leaching experiments were performed at 80°C in 2M HCl in two stages. The first stage consisted of classic leaching experiments of samples without and after thermal treatment. The second stage consisted of oxidative leaching experiments (blowing of air or oxygen with the aim to intensify metals leaching. The results of thermal treatment experiments show that maximal mass loss after burning (combustion was 53 % (700°C and after pyrolysis 47 % (900 %. Oxidative leaching resulted in complete dissolution of copper and tin after 60. or 90 minutes of thermally treated samples. Pyrolysis and combustion have positive effects on metals dissolution in comparison with samples without thermal pretreatment. Moreover, the dissolution of metals is more effective and needs shorter leaching time.

  10. Accelerating column leaching trial on copper sulfide ore

    Institute of Scientific and Technical Information of China (English)

    WANG Hongjiang; WU Aixiang; ZHOU Xun; WANG Shaoyong; ZHANG Jie

    2008-01-01

    The main measures to accelerate leaching sulfide ore are large spraying intensity,manual oxygen supply,temperature control and acclimated bacteria.The indoor experiment accelerating sulfide ore leaching detected the temperature during leaching process,dissolvability of oxygen,bacterial concentration,Cu concentration and slag grade.At the same time,this paper also analyzed the effect of four factors,which are bacterial diversity cultivation stage,spraying intensity,air supply,and whether to control temperature,on the leaching efficiency of copper.The results indicate that the oxygen content of leach solution has a close relationship with temperature but it is rarely affected by air supply.The bacterial concentration preserves from 106 to 107 mL-1,and temperature has a great effect on the bacterial activity under the condition of proper temperature and oxygen supply,and the lack of nutrition prevents the bacterial concentration from rising in the late stage.The relationships of the copper leaching efficiency to temperature,air feed,and spraying intensity are directly proportional.The leaching efficiencies of the cultivated bacteria and acclimation bacteria are 1.2 and 1.4 times as large as that of the original bacteria.

  11. Complex Leaching Process of Scheelite in Hydrochloric and Phosphoric Solutions

    Science.gov (United States)

    Liu, Liang; Xue, Jilai; Liu, Kang; Zhu, Jun; Wang, Zengjie

    2016-09-01

    The complex leaching process of synthetic scheelite and scheelite concentrate in hydrochloric and phosphoric solutions has been investigated for improving process efficiency. A higher leaching rate, compared with the classic acid leaching process, can be obtained through the synergy of HCl and H3PO4 with appropriate W/P mole ratio, temperature, and acid concentration. For synthetic scheelite, the optimum leaching conditions were W/P mole ratio 7:1, temperature 50°C, HCl 0.72 mol/L, and stirring speed 600 rpm; for scheelite concentrate, W/P mole ratio 7:1, temperature 80°C, HCl 2.16 mol/L, and stirring speed 1000 rpm. The leaching rates under the optimized conditions can reach up to 98% or even higher. FTIR spectra analysis confirmed that the leachate composition remained as H3[PW12O40] in the range of varying W/P mole ratios, so the PO4 3- in acidic solution and phosphorus content in the leaching product could be better controlled. The function 1 - (1 - X)1/3 against leaching time was applied to fit the experimental data, and the apparent activation energy, E a, was calculated as 60.65 kJ/mol. The results would be valuable for effectively using scheelite as a raw material resource for sustainable tungsten production.

  12. Dynamics of aluminum leaching from water purification sludge.

    Science.gov (United States)

    Cheng, Wen-Po; Fu, Chi-Hua; Chen, Ping-Hung; Yu, Ruey-Fang

    2012-05-30

    In this investigation, the shrinking core model is used to study the rate of aluminum salt leaching from water purification sludge (WPS). This model, which describes the aluminum leaching rate, can be developed to maximize the Al(III) recovering efficiency. Laboratory results indicate that when the mixing speed exceeds 80rpm, the effect of film diffusion control on the leaching process is greatly reduced, such that any further increase in the mixing speed does not affect the Al(III) leaching rate. Additionally, increasing the temperature or acid concentration improves Al(III) leaching rate. The laboratory data were verified by using the shrinking core model to confirm that the leaching of Al(III) from WPS is consistent with the inert-layer diffusion control model. This finding reveals that large amounts of SiO(2), Al(2)O(3) and other inert constituents will form an inter diffusion layer in the WPS and thus become the major limiting factors that control the Al(III) leaching process. The dynamic equation can be expressed as 1-3(1-x)(2/3)+2(1-x)=(2707.3 exp(-3887.6/T))t, in which the apparent activation energy and pre-exponential factors are 32.32 kJ/mol and 2707.3 min(-1), respectively, as determined by solving the Arrhenius equation.

  13. Defense High-Level Waste Leaching Mechanisms Program. Final report

    International Nuclear Information System (INIS)

    The Defense High-Level Waste Leaching Mechanisms Program brought six major US laboratories together for three years of cooperative research. The participants reached a consensus that solubility of the leached glass species, particularly solubility in the altered surface layer, is the dominant factor controlling the leaching behavior of defense waste glass in a system in which the flow of leachant is constrained, as it will be in a deep geologic repository. Also, once the surface of waste glass is contacted by ground water, the kinetics of establishing solubility control are relatively rapid. The concentrations of leached species reach saturation, or steady-state concentrations, within a few months to a year at 70 to 900C. Thus, reaction kinetics, which were the main subject of earlier leaching mechanisms studies, are now shown to assume much less importance. The dominance of solubility means that the leach rate is, in fact, directly proportional to ground water flow rate. Doubling the flow rate doubles the effective leach rate. This relationship is expected to obtain in most, if not all, repository situations

  14. Analysis of SPR salt cavern remedial leach program 2013.

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Paula D.; Gutierrez, Karen A.; Lord, David L.; Rudeen, David Keith

    2013-09-01

    The storage caverns of the US Strategic Petroleum Reserve (SPR) exhibit creep behavior resulting in reduction of storage capacity over time. Maintenance of oil storage capacity requires periodic controlled leaching named remedial leach. The 30 MMB sale in summer 2011 provided space available to facilitate leaching operations. The objective of this report is to present the results and analyses of remedial leach activity at the SPR following the 2011 sale until mid-January 2013. This report focuses on caverns BH101, BH104, WH105 and WH106. Three of the four hanging strings were damaged resulting in deviations from normal leach patterns; however, the deviations did not affect the immediate geomechanical stability of the caverns. Significant leaching occurred in the toes of the caverns likely decreasing the number of available drawdowns until P/D ratio criteria are met. SANSMIC shows good agreement with sonar data and reasonably predicted the location and size of the enhanced leaching region resulting from string breakage.

  15. Advances in Nitrogen Loss Leached by Precipitation from Plant Canopy

    Institute of Scientific and Technical Information of China (English)

    LI Shi-qing; JI Chun-rong; FANG Ya-ning; CHEN Xiao-li; LI Sheng-xiu

    2008-01-01

    Function of canopy in changing nutrient cycle and flux is one of the focuses in recent years. On the basis of comprehensively appraising published research, we analyzed the nitrogen loss leaching from plant canopy and several factors which affected it. We pointed out the disadvantages of the published researches and the key issues that ought to be solved: (1) The menstruation need to be advanced, and the research should be carried out on nitrogen loss leaching from the canopy of the field plant. (2) If the nitrogen is leached from the plant canopy, the research on the type of nitrogen loss should be carried out, and the nitrogen use efficiency of different varieties should be dealt on a research perspective with regard to the nitrogen leaching. (3) The research should be conducted on the mechanism and pathway, and the progress of nitrogen leaching; and the factors affecting nitrogen leaching should be included in the research, such as the leaf area of different growth stages, stomata densities, stomata conductance, and the apparent free space, which are beneficial to explain the mechanism of nitrogen leaching from the plant canopy.

  16. Kinetics of Uranium Extraction from Uranium Tailings by Oxidative Leaching

    Science.gov (United States)

    Zhang, Biao; Li, Mi; Zhang, Xiaowen; Huang, Jing

    2016-07-01

    Extraction of uranium from uranium tailings by oxidative leaching with hydrogen peroxide (H2O2) was studied. The effects of various extraction factors were investigated to optimize the dissolution conditions, as well as to determine the leaching kinetic parameters. The behavior of H2O2 in the leaching process was determined through scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX) and x-ray diffraction analysis of leaching residues. Results suggest that H2O2 can significantly improve uranium extraction by decomposing the complex gangue structures in uranium tailings and by enhancing the reaction rate between uranium phases and the leaching agent. The extraction kinetics expression was changed from 1 - 3(1 - α)2/3 + 2(1 - α) = K 0(H2SO4)-0.14903(S/L)-1.80435( R o)0.20023 e -1670.93/T t ( t ≥ 5) to 1 - 3(1 - α)2/3 + 2(1 - α) = K 0(H2SO4)0.01382(S/L)-1.83275( R o)0.25763 e -1654.59/T t ( t ≥ 5) by the addition of H2O2 in the leaching process. The use of H2O2 in uranium leaching may help in extracting uranium more efficiently and rapidly from low-uranium-containing ores or tailings.

  17. Defense High-Level Waste Leaching Mechanisms Program. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Mendel, J.E. (compiler)

    1984-08-01

    The Defense High-Level Waste Leaching Mechanisms Program brought six major US laboratories together for three years of cooperative research. The participants reached a consensus that solubility of the leached glass species, particularly solubility in the altered surface layer, is the dominant factor controlling the leaching behavior of defense waste glass in a system in which the flow of leachant is constrained, as it will be in a deep geologic repository. Also, once the surface of waste glass is contacted by ground water, the kinetics of establishing solubility control are relatively rapid. The concentrations of leached species reach saturation, or steady-state concentrations, within a few months to a year at 70 to 90/sup 0/C. Thus, reaction kinetics, which were the main subject of earlier leaching mechanisms studies, are now shown to assume much less importance. The dominance of solubility means that the leach rate is, in fact, directly proportional to ground water flow rate. Doubling the flow rate doubles the effective leach rate. This relationship is expected to obtain in most, if not all, repository situations.

  18. Kinetics of Uranium Extraction from Uranium Tailings by Oxidative Leaching

    Science.gov (United States)

    Zhang, Biao; Li, Mi; Zhang, Xiaowen; Huang, Jing

    2016-05-01

    Extraction of uranium from uranium tailings by oxidative leaching with hydrogen peroxide (H2O2) was studied. The effects of various extraction factors were investigated to optimize the dissolution conditions, as well as to determine the leaching kinetic parameters. The behavior of H2O2 in the leaching process was determined through scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX) and x-ray diffraction analysis of leaching residues. Results suggest that H2O2 can significantly improve uranium extraction by decomposing the complex gangue structures in uranium tailings and by enhancing the reaction rate between uranium phases and the leaching agent. The extraction kinetics expression was changed from 1 - 3(1 - α)2/3 + 2(1 - α) = K 0(H2SO4)-0.14903(S/L)-1.80435(R o)0.20023 e -1670.93/T t (t ≥ 5) to 1 - 3(1 - α)2/3 + 2(1 - α) = K 0(H2SO4)0.01382(S/L)-1.83275(R o)0.25763 e -1654.59/T t (t ≥ 5) by the addition of H2O2 in the leaching process. The use of H2O2 in uranium leaching may help in extracting uranium more efficiently and rapidly from low-uranium-containing ores or tailings.

  19. Extended Leach Testing of Simulated LAW Cast Stone Monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R. Jeffrey [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Westsik, Joseph H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Williams, Benjamin D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jung, H. B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Guohui [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-07-09

    This report describes the results from long-term laboratory leach tests performed at Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions (WRPS) to evaluate the release of key constituents from monoliths of Cast Stone prepared with four simulated low-activity waste (LAW) liquid waste streams. Specific objectives of the Cast Stone long-term leach tests described in this report focused on four activities: 1. Extending the leaching times for selected ongoing EPA-1315 tests on monoliths made with LAW simulants beyond the conventional 63-day time period up to 609 days reported herein (with some tests continuing that will be documented later) in an effort to evaluate long-term leaching properties of Cast Stone to support future performance assessment activities. 2. Starting new EPA-1315 leach tests on archived Cast Stone monoliths made with four LAW simulants using two leachants (deionized water [DIW] and simulated Hanford Integrated Disposal Facility (IDF) Site vadose zone pore water [VZP]). 3. Evaluating the impacts of varying the iodide loading (starting iodide concentrations) in one LAW simulant (7.8 M Na Hanford Tank Waste Operations Simulator (HTWOS) Average) by manufacturing new Cast Stone monoliths and repeating the EPA-1315 leach tests using DIW and the VZP leachants. 4. Evaluating the impacts of using a non-pertechnetate form of Tc that is present in some Hanford tanks. In this activity one LAW simulant (7.8 M Na HTWOS Average) was spiked with a Tc(I)-tricarbonyl gluconate species and then solidified into Cast Stone monoliths. Cured monoliths were leached using the EPA-1315 leach protocol with DIW and VZP. The leach results for the Tc-Gluconate Cast Stone monoliths were compared to Cast Stone monoliths pertechnetate.

  20. Prostanoids modulate inflammation and alloimmune responses during graft rejection

    Directory of Open Access Journals (Sweden)

    P.N. Rocha

    2005-12-01

    Full Text Available Acute rejection of a transplanted organ is characterized by intense inflammation within the graft. Yet, for many years transplant researchers have overlooked the role of classic mediators of inflammation such as prostaglandins and thromboxane (prostanoids in alloimmune responses. It has been demonstrated that local production of prostanoids within the allograft is increased during an episode of acute rejection and that these molecules are able to interfere with graft function by modulating vascular tone, capillary permeability, and platelet aggregation. Experimental data also suggest that prostanoids may participate in alloimmune responses by directly modulating T lymphocyte and antigen-presenting cell function. In the present paper, we provide a brief overview of the alloimmune response, of prostanoid biology, and discuss the available evidence for the role of prostaglandin E2 and thromboxane A2 in graft rejection.

  1. [Dynamic change of phosphorus leaching of neutral purple soil at different re-wetting rate].

    Science.gov (United States)

    Zhang, Si-Lan; Shi, Xiao-Jun; Guo, Tao

    2014-03-01

    Re-wetting was one of the most common forms of abiotic stresses experienced by soils. To investigate the effects of soil re-wetting rate on phosphorus (P) leaching and the relationship between soil microbial biomass carbon (MBC) and forms of P in leachate; five kinds of neutral purple soils of different fertilizer treatments were analyzed using simulating lab test at re-wetting rate of 0 h, 2 h, 4 h, 24 h and 48 h. The results showed that: (1) The lowest content of MBC appeared at the rate of 2 h during the soil re-wetting process, and the content of MBC increased with the reducing re-wetting rate. (2) Slower re-wetting helped to enhance soil microbial activity and the enhancement effect of organic fertilizer with NPK fertilizer (MNPK) was more significant. (3) The P leaching events of all fertilizer treatments occurred mainly at rapid re-wetting rates such as 0 h, 2 h, 4 h. Slower re-wetting was an important measure to prevent P leaching especially for the soils applied with chemical fertilizers, and it was of great significance in the field management of P. (4) Dissolved organic phosphorus (DOP) was the primary leaching part in leachate, and the variation range of ratio of total dissolved phosphorus (TDP) to total phosphorus (TP) and DOP to TP was 35.42%-85.99% and 29.74%-78.58% respectively. (5) With the reducing of re-wetting rate, significant negative correlation was observed between MBC and TP, TDP as well as DOP in the leachate (P < 0.05). To sum up, it was speculated that the P in soil leachate mainly came from soil microorganisms. PMID:24881404

  2. Improved ZigBee Network Routing Algorithm Based on LEACH

    Science.gov (United States)

    Zhao, Yawei; Zhang, Guohua; Xia, Zhongwu; Li, Xinhua

    Energy efficiency design of routing protocol is a kind of the key technologies used to wireless sensor networks. The paper introduces the ZigBee technology, summarizes the current transmitting routing model in wireless sensor networks, and finds that the traditional LEACH protocol can lead to overload of some cluster head nodes. The paper suggested that the existing LEACH agreement was improved and the new algorithm was better than traditional LEACH routing algorithm by the comprasion of simulation. The improved routing algorithm can prolong the networks lifetime and effectively save the scarce energy.

  3. DESIGN OF AN EXPERT CONTROL SYSTEM FOR LEACHING PROCESS

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    One important step in zinc hydrometallurgy is the leaching process, which involves the dissolving of zinc-bearing material in dilute sulfuric acid to form zinc sulfate solution. The key problem in the process control is to determine the optimal pHs of the overflows of the continuous leaches and track them. An expert control system for the leaching process was designed to solve the key problem. A methodology is proposed for determining and tracking the optimal pHs with an expert control strategy based on a combination of steadystate mathematical models and rule models of the process.

  4. Leaching studies for metals recovery from printed circuit boards scrap

    OpenAIRE

    Oliveira, Paula C.; Cabral, Marta; Taborda, F. Charters; Margarido, F.; Nogueira, C. A.

    2009-01-01

    In this paper, the leaching behavior of the major metals present in printed circuit boards waste is evaluated, aiming at its recycling by hydrometallurgy. Several leachants were compared (sulfuric, hydrochloric and nitric acids, at 2 M H+ concentration), at temperatures of 25ºC and 90ºC and 4 hours of reaction time. Sulfuric acid leaching was not very promising concerning metals dissolution being only effective for iron. Hydrochloric acid allowed the leaching up to 60% of tin and about 50% of...

  5. Leaching from solidified waste forms under saturated and unsaturated conditions

    International Nuclear Information System (INIS)

    The leaching behavior of nitrate ion from a cement based waste form containing low-level radioactive waste was shown to be identical under saturated and unsaturated soil conditions. Only in soils containing less than 2 wt %water did the leach rate decrease. The observation of identical leach rates under saturated and unsaturated conditions is explained by diffusion through the waste form being the limiting step. Diffusion through the soil decreases in very dry soil and the limiting step changes. These laboratory tests were verified by measurements on similar, Portland cement based waste form in a field lysimeter

  6. PEP Support Laboratory Leaching and Permeate Stability Tests

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Renee L.; Peterson, Reid A.; Rinehart, Donald E.; Buchmiller, William C.

    2009-09-25

    Pacific Northwest National Laboratory (PNNL) has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Hanford Tank Waste Treatment and Immobilization Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility (PTF). The Pretreatment Engineering Platform (PEP) was designed, constructed, and operated as part of a plan to respond to issue M12, "Undemonstrated Leaching Processes," of the External Flowsheet Review Team (EFRT) issue response plan.( ) The PEP is a 1/4.5-scale test platform designed to simulate the WTP pretreatment caustic leaching, oxidative leaching, ultrafiltration solids concentration, and slurry washing processes. The PEP replicates the WTP leaching processes using prototypic equipment and control strategies. A simplified flow diagram of the PEP system is shown in Figure 1.1. Two operating scenarios are currently being evaluated for the ultrafiltration process (UFP) and leaching operations. The first scenario has caustic leaching performed in the UFP-2 ultrafiltration feed vessels (i.e., vessel UFP-VSL-T02A in the PEP and vessels UFP-VSL-00002A and B in the WTP PTF). The second scenario has caustic leaching conducted in the UFP-1 ultrafiltration feed preparation vessels (i.e., vessels UFP-VSL-T01A and B in the PEP and vessels UFP-VSL-00001A and B in the WTP PTF). In both scenarios, 19-M sodium hydroxide solution (NaOH, caustic) is added to the waste slurry in the vessels to leach solid aluminum compounds (e.g., gibbsite, boehmite). Caustic addition is followed by a heating step that uses direct injection of steam to accelerate the leach process. Following the caustic leach, the vessel contents are cooled using vessel cooling jackets and/or external heat exchangers. The main difference between the two scenarios is that for leaching in UFP-VSL-T01A and B, the 19-M NaOH is added to un-concentrated waste slurry (3 to 8 wt% solids), while for leaching in

  7. Rejected! Cognitions of rejection and intergroup anxiety as mediators of the impact of cross-group friendships on prejudice.

    Science.gov (United States)

    Barlow, Fiona Kate; Louis, Winnifred R; Hewstone, Miles

    2009-09-01

    In a sample of White Australians (N=273), cross-group friendship with Aboriginal Australians was associated with reduced cognitions of rejection and intergroup anxiety, and these variables fully mediated the effect of cross-group friendship on conversational avoidance of sensitive intergroup topics, active avoidance of the outgroup, and old-fashioned prejudice. The novel mediator proposed here, cognitions of rejection, predicted intergroup anxiety, and also predicted the three outcome variables via intergroup anxiety. Over and above its indirect effects via anxiety, cognitions of rejection directly predicted both conversational and active avoidance, suggesting that whilst the cognitive and affective mediators are linked, they predict intergroup outcomes in different ways. The results demonstrate the beneficial impact of cross group friendship in reducing prejudice and avoidance by diminishing cognitions of rejection and intergroup anxiety. We also highlight that individuals without cross-group friends may perceive the outgroup as rejecting, feel anxious about cross-group interaction, and desire both conversational and physical avoidance of the outgroup.

  8. A Longitudinal Study of Rejecting and Autonomy-Restrictive Parenting, Rejection Sensitivity, and Socioemotional Symptoms in Early Adolescents.

    Science.gov (United States)

    Rowe, Susan L; Gembeck, Melanie J Zimmer; Rudolph, Julia; Nesdale, Drew

    2015-08-01

    Rejection sensitivity (RS) has been defined as the tendency to readily perceive and overreact to interpersonal rejection. The primary aim of this study was to test key propositions of RS theory, namely that rejecting experiences in relationships with parents are antecedents of early adolescents' future RS and symptomatology. We also expanded this to consider autonomy-restrictive parenting, given the importance of autonomy in early adolescence. Participants were 601 early adolescents (age 9 to 13 years old, 51% boys) from three schools in Australia. Students completed questionnaires at school about parent and peer relationships, RS, loneliness, social anxiety, and depression at two times with a 14-month lag between assessments. Parents also reported on adolescents' difficulties at Time 1 (T1). It was anticipated that more experience of parental rejection, coercion, and psychological control would be associated with adolescents' escalating RS and symptoms over time, even after accounting for peer victimisation, and that RS would mediate associations between parenting and symptoms. Structural equation modelling supported these hypotheses. Parent coercion was associated with adolescents' increasing symptoms of social anxiety and RS over time, and parent psychological control was associated with increasing depressive symptoms over time. Indirect effects via RS were also found, with parent rejection and psychological control linked to higher T1 RS, which was then associated with increasing loneliness and RS. Lastly, in a separate model, peer victimisation and RS, but not parenting practices, were positively associated with concurrent parent reports of adolescents' difficulties.

  9. An image rejection circuit with sign detection only

    OpenAIRE

    Lerstaveesin, Supisa

    2006-01-01

    In direct-conversion receivers, radio frequency (RF) signals are down-converted to zero or low intermediate frequency (IF) using complex in-phase and quadrature (I/Q) mixers with no prior image filtering. Due to I/Q path gain and phase errors, image leaks into the signal band during the down-conversion process. A generic image rejection algorithm is proposed to reject image in the baseband using a zero-forcing sign-sign adaptive feedback concept. The orthonormal property of complex I/Q channe...

  10. Solar dynamic organic Rankine cycle heat rejection system simulation

    Science.gov (United States)

    Havens, V. N.; Ragaller, D. R.; Namkoong, D.

    1987-01-01

    The use of a rotary fluid management device (RFMD) and shear flow condenser for two-phase fluid management in microgravity organic Rankine cycle (ORC) applications is examined. A prototype of the proposed Space Station ORC heat rejection system was constructed to evaluate the performance of the inventory control method. The design and operation of the RFMD, shear flow condenser, and inventory control fluid accumulator are described. A schematic diagram of the ORC, RFMD, and condenser, and a functional diagram of the heat rejection system for the ORC are presented.

  11. Belief decision support and reject for textured images characterization

    CERN Document Server

    Martin, Arnaud

    2008-01-01

    The textured images' classification assumes to consider the images in terms of area with the same texture. In uncertain environment, it could be better to take an imprecise decision or to reject the area corresponding to an unlearning class. Moreover, on the areas that are the classification units, we can have more than one texture. These considerations allows us to develop a belief decision model permitting to reject an area as unlearning and to decide on unions and intersections of learning classes. The proposed approach finds all its justification in an application of seabed characterization from sonar images, which contributes to an illustration.

  12. Causes of rejection of beef bulls in breeding soundness evaluation

    Directory of Open Access Journals (Sweden)

    Silvio Renato Oliveira Menegassi

    2012-07-01

    Full Text Available The objective of this study was to analyze the rates of rejection in the different steps of the breeding soundness evaluation of beef bulls in the state of Rio Grande do Sul, Brazil. The breeding soundness of 22,113 young and mature bulls of 14 beef breeds, participating in the Program of Reproductive Evaluation (PARTO was evaluated in the experiment. Data concerning to the causes of rejection in the four steps of the breeding soundness evaluation (general physical examination, genital tract examination, semen evaluation and sexual behavior assessment were analyzed by the Chi-square test and univariate regression analysis. According to year, general physical examination, genital tract examination and semen evaluation determined the rejection of 0.9% to 2.5%, 5.1% to 7.7%, 1.8% to 5.3%; and 4.2% to 6.7%, 7.3 to 9.3%, and 2.5% to 5.5% of young and mature bulls, respectively. Mature bulls presented higher chances of rejection than young bulls in the general physical examination in every year evaluated; as to the genital tract examination, their chances of rejection were higher in years I and II, but not in year III. In the semen evaluation, there was no difference between the ages assessed in any of the three years evaluated. Sexual behavior assessment accounted for the rejection of 1.9 to 6.0% of the young bulls and 2.9% to 3.9% of mature bulls, in accordance with the years evaluated; in years I and II, mature bulls presented higher rejection rates than young bulls. These results confirm the importance of performing all steps of the breeding soundness evaluation, including the sexual behavior assessment as a work routine, rather than an additional, optional stage of the evaluation, which should be carried out before the breeding season. The results indicate the relationship between bull age and rejection rate in the breeding soundness evaluation.

  13. Acute renal transplant rejections: A single center experience

    Directory of Open Access Journals (Sweden)

    Jabur Wael

    2008-01-01

    Full Text Available We undertook this observational study to assess the incidence of acute rejections (AR in the first six months after transplantation at Al-Karama Hospital, Iraq. Sixty eight patients (49 males and 19 females underwent renal transplantation in 2006 and were followed up weekly. Forty six received kidneys from related donors and 22 from unrelated donors. During the first six months after transplantation AR occurred in 16 patients (23%; 11 (23% related and 5 (23% unrelated donor transplantation. We conclude that the incidence of acute rejection was similar in related and unrelated donor transplantation and the general incidence was comparable to that reported from most centers.

  14. Variation of the phytotoxicity of municipal solid waste incinerator bottom ash on wheat (Triticum aestivum L.) seed germination with leaching conditions.

    Science.gov (United States)

    Phoungthong, Khamphe; Zhang, Hua; Shao, Li-Ming; He, Pin-Jing

    2016-03-01

    Municipal solid waste incinerator bottom ash (MSWIBA) has long been regarded as an alternative building material in the construction industry. However, the pollutants contained in the bottom ash could potentially leach out and contaminate the local environment, which presents an obstacle to the reuse of the materials. To evaluate the environmental feasibility of using MSWIBA as a recycled material in construction, the leaching derived ecotoxicity was assessed. The leaching behavior of MSWIBA under various conditions, including the extractant type, leaching time, liquid-to-solid (L/S) ratio, and leachate pH were investigated, and the phytotoxicity of these leachates on wheat (Triticum aestivum L.) seed germination was determined. Moreover, the correlation between the germination index and the concentrations of various chemical constituents in the MSWIBA leachates was assessed using multivariate statistics with principal component analysis and Pearson's correlation analysis. It was found that, heavy metal concentrations in the leachate were pH and L/S ratio dependent, but were less affected by leaching time. Heavy metals were the main pollutants present in wheat seeds. Heavy metals (especially Ba, Cr, Cu and Pb) had a substantial inhibitory effect on wheat seed germination and root elongation. To safely use MSWIBA in construction, the potential risk and ecotoxicity of leached materials must be addressed.

  15. 石煤焙烧—加压酸浸提钒研究%Study on Roasting-Pressure Acid Leaching of Vanadium from Stone Coal

    Institute of Scientific and Technical Information of China (English)

    黄俊; 张一敏; 黄晶; 刘涛; 薛楠楠

    2015-01-01

    In order to find a process which could increase the leaching velocity of vanadium,roasting-pressure acid leac-hing of vanadium on stone coal from Tongshan in Hubei was investigated. Results showed that,the optimal operation conditions are as followed:the roasting temperature was 850 ℃,the roasting time was 60 min,the kettle pressure was 1. 0 MPa,initial concentration of sulfuric acid was 15%,ratio of liquid to solid was 1. 5 mL/g,leaching temperature was 150 ℃ and leaching time was 120 min,with these conditions the vanadium leaching rate could reach 80. 51%. The changes of mica mineral struc-ture during leaching process were analyzed by Infrared Spectrometry analysis and the effect of temperature on vanadium effi-ciency was studied from the aspect of leaching kinetics. The results indicated that pressure acid leaching could destruct the crystal lattice of mica that was helpful for the release of vanadium and the increase of vanadium leaching efficiency. The leac-hing kinetics analysis results indicated that:effect of leaching temperature on vanadium efficiency was conspicuous,when the leaching temperature ranged from 60 to 120 ℃,the apparent activation energy was 41. 603 kJ/mol and the leaching was con-trolled by surface chemical reaction. When the temperature ranged from 150 to 210 ℃, the apparent activation energy was 4. 319 kJ/mol and the leaching was controlled by inner diffusion of reactants. As pressure acid leaching could raise the leac-hing temperature over 100 ℃,the destruction velocity of mica crystal lattice could be raised effectively and the vanadium leac-hing time could be shorten effectively.%为探索提高石煤中钒的浸出效率,以湖北通山某石煤矿石为研究对象,进行了石煤焙烧—加压酸浸提钒工艺研究. 结果表明:在焙烧温度为850 ℃、焙烧时间为60 min、釜内压力为1. 0 MPa、硫酸初始浓度为15%、液固比为1. 5 mL/g、浸出温度为150 ℃、浸出时间为120 min

  16. CD4+ T Lymphocytes are Not Necessary for the Acute Rejection of Vascularized Mouse Lung Transplants

    OpenAIRE

    Gelman, Andrew E.; Okazaki, Mikio; Lai, Jiaming; Kornfeld, Christopher G.; Kreisel, Friederike H.; Richardson, Steven B.; Sugimoto, Seiichiro; Tietjens, Jeremy R.; Patterson, G. Alexander; Krupnick, Alexander S.; Kreisel, Daniel

    2008-01-01

    Acute rejection continues to present a major obstacle to successful lung transplantation. While CD4+ T lymphocytes are critical for the rejection of some solid organ grafts the role of CD4+ T cells in the rejection of lung allografts is largely unknown. In this study we demonstrate in a novel model of orthotopic vascularized mouse lung transplantation that acute rejection of lung allografts is independent of CD4+ T cell-mediated allorecognition pathways. CD4+ T cell-independent rejection occu...

  17. Effects of Pregnant Leach Solution Temperature on the Permeability of Gravelly Drainage Layer of Heap Leaching Structures

    Directory of Open Access Journals (Sweden)

    mehdi amini

    2013-12-01

    Full Text Available In copper heap leaching structures, the ore is leached by an acidic solution. After dissolving the ore mineral, the heap is drained off in the acidic solution using a drainage system (consisting of a network of perforated polyethylene pipes and gravelly drainage layers and is, then, transferred to the leaching plant for copper extraction where the copper is extracted and the remaining solution is dripped over the ore heap for re-leaching. In this process, the reaction between the acidic solution and copper oxide ore is exothermal and the pregnant leach solution (PLS, which is drained off the leaching heap, has a higher temperature than the dripped acidic solution. The PLS temperature variations cause some changes in the viscosity and density which affect the gravelly drainage layer's permeability. In this research, a special permeability measuring system was devised for determining the effects of the PLS temperature variations on the permeability coefficient of the gravelly drainage layer of heap leaching structures. The system, consisting of a thermal acid resistant element and a thermocouple, controls the PLS temperature, which helps measure the permeability coefficient of the gravelly drainage layer. The PLS and gravelly drainage layer of Sarcheshmeh copper mine heap leaching structure No. 1 were used in this study. The permeability coefficient of the gravelly soil was measured against the PLS and pure water at temperatures varying between 3°C to 60°C. Also, the viscosity and density of the PLS and pure water were measured at these temperatures and, using existing theoretical relations, the permeability coefficient of the gravel was computed. A comparison between the experimental and theoretical results revealed a good conformity between the two sets of results. Finally, a case (Taft heap leaching structure, Yazd, Iran was studied and its gravelly drainage layer was designed based on the results of the present research.

  18. Kinetic investigations of oxidative roasting and afterwards leaching of copper-lead matte

    Directory of Open Access Journals (Sweden)

    Minić Duško

    2004-01-01

    Full Text Available In this paper, results of copper - lead matte investigations are presented. Investigated copper-lead matte is intermediate product of lead production in TREPCA-Zvecan. In the first part of the paper characterization of starting material is presented, consisting of: chemical composition analysis (XRQ, sceaning electron microscopy (SEM and diffractometry (XRD. Thermal properties of matte investigated were determined using differential thermal analysis (DTA at characteristic temperatures. Using results of induced analysis, mechanism of matte oxidation process was determined. In second part of the paper kinetic parameters describing oxidative roasting and afterwards leaching in sulfuric acid of copper-lead mate are presented.

  19. Leaching tests of cemented organic radioactive waste

    International Nuclear Information System (INIS)

    The use of radioisotopes in research, medical and industrial activities generates organic liquid radioactive wastes. At Centro de Desenvolvimento da Tecnologia Nuclear (CDTN) are produced organic liquid wastes from different sources, one of these are the solvent extraction activities, whose the waste volume is the largest one. Therefore a research was carried out to treat them. Several techniques to treat organic liquid radioactive wastes have been evaluated, among them incineration, oxidation processes, alkaline hydrolysis, distillation, absorption and cementation. Laboratory experiments were accomplished to establish the most adequate process in order to obtain qualified products for storage and disposal. Absorption followed by cementation was the procedure used in this study, i.e. absorbent substances were added to the organic liquid wastes before mixing with the cement. Initially were defined the absorbers, and evaluated the formulation in relation to the compressive strength of its products. Bentonite from different suppliers (B and G) and vermiculite in two granulometries (M - medium and F - small) were tested. In order to assess the product quality the specimens were submitted to the leaching test according the Standard ISO 6961 and its results were evaluated. Then they were compared with the values established by Standard CNEN NN 6.09 Acceptance criteria for waste products to be disposed, to verify if they meet the requirements for safely storage and disposal. Through this study the best formulations to treat the organic wastes were established. (author)

  20. Bacterial oxidation activity in heap leaching

    Institute of Scientific and Technical Information of China (English)

    柳建设; 夏海波; 王兆慧; 胡岳华

    2004-01-01

    Bioleaching of sulfide minerals by bacteria, mainly Thiobacillus ferrooxidans (T. f. ) and Thiobacillus thiooxidans, plays an important role in hydrometallurgy because of its economic and environmental attractions. The surveys of production process and the bacterial oxidation activity in the heap bioleaching were investigated. The results show that pH value is high, bacteria biomass and ferric concentration are low, generation time (above 7.13 h)is long in leachate, and less bacteria are adsorbed on the ores. The bacteria in the leachate exposing on the surface and connecting with mineral, have much faster oxidation rate of Fe( Ⅱ ) and shorter generation time, compared with those which are in the reservoir for a long time. There is diversity for oxidation activity of Fe( Ⅱ ), while there is no diversity for oxidation of sulfur. So it is advisable to add sulfuric acid to degrade pH value to 2.0, add nutrients and shorten recycling time of leachate, so as to enhance bacteria concentration of leachate and the leaching efficiency.

  1. Birch (Betula spp.) wood biochar is a potential soil amendment to reduce glyphosate leaching in agricultural soils.

    Science.gov (United States)

    Hagner, Marleena; Hallman, Sanna; Jauhiainen, Lauri; Kemppainen, Riitta; Rämö, Sari; Tiilikkala, Kari; Setälä, Heikki

    2015-12-01

    Glyphosate (N-(phosphonomethyl) glycine), a commonly used herbicide in agriculture can leach to deeper soil layers and settle in surface- and ground waters. To mitigate the leaching of pesticides and nutrients, biochar has been suggested as a potential soil amendment due to its ability to sorb both organic and inorganic substances. However, the efficiency of biochar in retaining agro-chemicals in the soil is likely to vary with feedstock material and pyrolysis conditions. A greenhouse pot experiment, mimicking a crop rotation cycle of three plant genera, was established to study the effects of pyrolysis temperature on the ability of birch (Betula sp.) wood originated biochar to reduce the leaching of (i) glyphosate, (ii) its primary degradation product AMPA and (iii) phosphorus from the soil. The biochar types used were produced at three different temperatures: 300 °C (BC300), 375 °C (BC375) and 475 °C (BC475). Compared to the control treatment without biochar, the leaching of glyphosate was reduced by 81%, 74% and 58% in BC300, BC375 and BC475 treated soils, respectively. The respective values for AMPA were 46%, 39% and 23%. Biochar had no significant effect on the retention of water-soluble phosphorus in the soil. Our results corroborate earlier findings on pesticides, suggesting that biochar amendment to the soil is a promising way to reduce also the leaching of glyphosate. Importantly, the ability of biochar to adsorb agro-chemicals depends on the temperature at which feedstock is pyrolysed. PMID:26342266

  2. Birch (Betula spp.) wood biochar is a potential soil amendment to reduce glyphosate leaching in agricultural soils.

    Science.gov (United States)

    Hagner, Marleena; Hallman, Sanna; Jauhiainen, Lauri; Kemppainen, Riitta; Rämö, Sari; Tiilikkala, Kari; Setälä, Heikki

    2015-12-01

    Glyphosate (N-(phosphonomethyl) glycine), a commonly used herbicide in agriculture can leach to deeper soil layers and settle in surface- and ground waters. To mitigate the leaching of pesticides and nutrients, biochar has been suggested as a potential soil amendment due to its ability to sorb both organic and inorganic substances. However, the efficiency of biochar in retaining agro-chemicals in the soil is likely to vary with feedstock material and pyrolysis conditions. A greenhouse pot experiment, mimicking a crop rotation cycle of three plant genera, was established to study the effects of pyrolysis temperature on the ability of birch (Betula sp.) wood originated biochar to reduce the leaching of (i) glyphosate, (ii) its primary degradation product AMPA and (iii) phosphorus from the soil. The biochar types used were produced at three different temperatures: 300 °C (BC300), 375 °C (BC375) and 475 °C (BC475). Compared to the control treatment without biochar, the leaching of glyphosate was reduced by 81%, 74% and 58% in BC300, BC375 and BC475 treated soils, respectively. The respective values for AMPA were 46%, 39% and 23%. Biochar had no significant effect on the retention of water-soluble phosphorus in the soil. Our results corroborate earlier findings on pesticides, suggesting that biochar amendment to the soil is a promising way to reduce also the leaching of glyphosate. Importantly, the ability of biochar to adsorb agro-chemicals depends on the temperature at which feedstock is pyrolysed.

  3. STUDY ON HIGH ACID LEACHING REACTIVE CALCINED KAOLIN

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Leaching experiments on metakaolin show that the final Al extraction ratio reached in a batch reaction is strikingly influenced by the inferior pore structure geometry of the metakaolin pellets. By calcining kaolin particles adhered in low humidity state,a variety of metakaolin pellet,inside which a large openings structure developed,has been prepared. The structure remarkably benefits leachant ion transference,so,the variety has high acid leaching reactivity,even coarse as the pellets are,its aluminum extracted ratio still has a linear relationship with leaching time,and the leaching kinetics is maintained zero order up to a significant conversion degree. A revised Pellet-Particle Model has been developed to interpret the structure influence on Al extraction ratio.

  4. Leaching of trace elements from coal solid waste

    International Nuclear Information System (INIS)

    In the present work leaching of ash from coal-fired power plants is described and the elemental analysis of coal, ash and leachates has been performed by neutron activation analysis, atomic absorption spectrometry and ion chromatography. The research concerns precipitator ash from powder-coal fired utilities, desulfurization ash from a dry-scrubbing process and fabric filter ash from a fluidized-bed boiler. Reproducibility of shake tests and column leaching has been studied. In the shake tests a wide range of solid to liquid ratios is applied, which allows extrapolation to column conditions. Column experiments carried out in upflow at a fixed flow-rate of approximately 1 cm per day showed good column performance and proved that equilibrium is reached fairly rapidly. A classification of precipitator ashes with respect to leaching behaviour is given, which allows an estimate of leaching characteristics beforehand. In relation to this variability in coal and ash compositions has been studied. (Auth.)

  5. Leaching of nutrient salts from fly ash from biomass combustion

    DEFF Research Database (Denmark)

    Thomsen, Kaj; Vu, Duc Thuong; Stenby, Mette;

    2005-01-01

    Methods to selectively leach nutrient salts from fly ash, while leaving cadmium un-dissolved were studied. Temperature, pH, water to fly ash ratio are all expected to influence the kinetics and the equilibrium boundaries for this process. Three different leaching methods were investigated. The...... moving bed process with agitation/centrifugation. It was found that a satisfactory leaching of the nutrient salts could be achieved with the third method using only two or three stages, depending on the water to fly ash ratio. It is an advantage to perform the process at temperatures above 50°C as the...... first method was a counter current moving bed process in four stages. The ash was kept in filter bags and leached with water that was introduced into the bags at 40-50°C. In the second method, fly ash and water was brought into contact in a partially fluidized bed. The third method was a counter current...

  6. Molybdenum removal from copper ore concentrate by sodium hypochlorite leaching

    Institute of Scientific and Technical Information of China (English)

    Liu Youcai; Zhong Hong; Cao Zhanfang

    2011-01-01

    The removal of molybdenum from a copper ore concentrate by sodium hypochlorite leaching was investigated. The results show that leaching time, liquid to solid ratio, leaching ternperature, agitation speed, and sodium hypochlorite and sodium hydroxide concentrations all have a significant effect on the removal of molybdenum. The optimum process operating parameters were found to be: time, 4 h: sodium hydroxide concentration, 10%; sodium hypochlorite concentration, 8%; liquid to solid ratio, 10:1; temperature, 50℃; and,agitation speed, 500 r/min. Under these conditions the extraction of molybdenum is greater than 99.9% and the extraction of copper is less than 0.01%. A shrinking particle model could be used to describe the leaching process. The apparent activation energy of the dissolution reaction was found to be approximately 8.8 kJ/mol.

  7. The leaching behavior of simulated HLW glass under repository condition

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    As the multibarrier system has been adopted to dispose HLW glass in geological formation in many countries, it was important to study the leaching behavior of vitrification under geological formation. This article describes the leaching behavior of simulated high level waste glass (90Nd/10), which can incorporate 16 wt.% simulated HLW in five kinds of geological media, such as granite, cement, bentonite, Fe3O4, etc. The durable experimental results show that the glass had less mass loss in granite and more mass loss in bentonite after a two-year leaching test. The SEM/XEDS analysis shows some element distributions on the leached specimen's surface, i.e., Na, Si and Mg elements were reduced on the specimen's surface, whereas Ba, Al, and Fe were enriched on the specimen's surface.

  8. An Energy Balanced Algorithm of LEACH Protocol in WSN

    Directory of Open Access Journals (Sweden)

    Chunyao Fu

    2013-01-01

    Full Text Available In wireless sensor networks (WSNs, due to the limitation of nodes energy, energy efficiency is an important factor should be considered when the protocols are designing. As a typical representative of hierarchical routing protocols, LEACH Protocol plays an important role. In response to the uneven energy distribution that is caused by the randomness of cluster heads forming , this paper proposes a new improved algorithm of LEACH protocol (LEACH-TLCH which is intended to balance the energy consumption of the entire network and extend the life of the network . The new algorithm is emulated by Matlab simulation platform, the simulation results indicate that both energy efficiency and the lifetime of the network are better than that of LEACH Protocol.

  9. Kinetics of molybdenite oxidizing leaching in alkali medium by ozone

    International Nuclear Information System (INIS)

    On the basis of investigation of the process kinetics proposed is a model of oxidizing leaching of molybdenite in alkali medium while ozonization of the solution by ozoneair mixture. A kinetic equation is derived, that describes experimental data satisfactorily

  10. Electrochemistry of a semiconductor chalcopyrite concentrate leaching by Thiobacillus ferrooxidans

    Science.gov (United States)

    Torma, A. E.

    1991-05-01

    Using carbon-paste-CuFeS2 electrodes and a cyclic voltammetric technique, it was found that a large number of intermediate electrochemical oxidation reactions were associated with the dissolution of chalcopyrite in presence and absence of bacteria. The effects of concentrations of copper, ferrous and ferric ions, as well as of agitation on the peaks of cyclic voltammograms were measured. It was established that chalcopyrite oxidation was solid-state controlled as suggested by the data of chronopotentiometric and chronoamperometric measurements. The activation energy of solid state diffusion of chalcopyrite leaching was determined by the Sand's method to be delta E(sub a) = 20.5 kJ. The leaching mechanism is discussed in terms of solid-state properties (energy bonding) of the n-type semiconductor chalcopyrite and energy density states of redox systems of acidic bacterial leach media. A generalized model for the mechanism of chalcopyrite leaching in presence and absence of bacteria is presented.

  11. Study on ore stacking after blasting for stope leaching uranium

    International Nuclear Information System (INIS)

    Geology of ore deposits, technical conditions, mining methods and blasting parameters of in-situ leaching uranium after blasting for an outcrop ore body are introduced. Long hole blast is beneficial technique and can bring better economic benefits

  12. CODCr leaching rules of municipal solid waste in Songtao Reservoir,Hainan Province,China

    Institute of Scientific and Technical Information of China (English)

    陈大勇; 王里奥

    2009-01-01

    By the means of static leaching experiment and dynamic leaching experiment,CODCr leaching rules of dumped MSW(Municipal Solid Waste) in Songtao Reservoir,Hainan Province,China,were studied. And according to academic experience and fitted results of experiment data,the models of CODCr leaching rules in the leaching condition were deduced. The static leaching experiment indicates that,both in water-changing section and no-water-changing section,the ratio of liquid to solid has a remarkable influence on CODCr leaching concentration. The exponential model could be established to approximately describe CODCr leaching rules and the curve fits well. The dynamic leaching experiment indicates that,leaching rules of MSW can be approximately described by power model,which can well fit the leaching experiment data. By the contrast of the static leaching experiment and dynamic leaching experiment,the differences of CODCr leaching rules between the two experiments are significant. By the exponential model,the average static leaching rate of CODCr is calculated as 882.24 mg/(kg·d) for water-changing section and 320.39 mg/(kg·d) for no-water-changing section; by the power model,the average dynamic leaching rate of CODCr is 208.77 mg/(kg·d).

  13. Mathematical modelling in leaching studies of radioactive waste

    International Nuclear Information System (INIS)

    Transport phenomena involved in the leaching of a radioactive material from a composite matrix into surrounding water are investigated using three methods based on theoretical equations. These arc: diffusion equation derived for a plane source model, rate equation for diffusion coupled with a first-order reaction and an empirical method employing a polynomial equation. The obtained results are compared with respect to their applicability to the 60Co and 137Cs leaching data. (author)

  14. Steady-state leaching of tritiated water from silica gel

    DEFF Research Database (Denmark)

    Das, H.A.; Hou, Xiaolin

    2009-01-01

    Aqueous leaching of tritium from silica gel, loaded by absorption of water vapor, makes part of reactor de-commissioning. It is found to follow the formulation of steady-state diffusion.......Aqueous leaching of tritium from silica gel, loaded by absorption of water vapor, makes part of reactor de-commissioning. It is found to follow the formulation of steady-state diffusion....

  15. Improving hydrolysis of food waste in a leach bed reactor

    International Nuclear Information System (INIS)

    Highlights: • This paper assesses leaching of food waste in a two phase digestion system. • Leaching is assessed with and without an upflow anaerobic sludge blanket (UASB). • Without the UASB, low pH reduces hydrolysis, while increased flows increase leaching. • Inclusion of the UASB increases pH to optimal levels and greatly improves leaching. • The optimal conditions are suggested as low flow with connection to the UASB. - Abstract: This paper examines the rate of degradation of food waste in a leach bed reactor (LBR) under four different operating conditions. The effects of leachate recirculation at a low and high flow rate are examined with and without connection to an upflow anaerobic sludge blanket (UASB). Two dilution rates of the effective volume of the leach bed reactors were investigated: 1 and 6 dilutions per LBR per day. The increase in dilution rate from 1 to 6 improved the destruction of volatile solids without connection to the UASB. However connection to the UASB greatly improved the destruction of volatile solids (by almost 60%) at the low recirculation rate of 1 dilution per day. The increase in volatile solids destruction with connection to the UASB was attributed to an increase in leachate pH and buffering capacity provided by recirculated effluent from the UASB to the leach beds. The destruction of volatile solids for both the low and high dilution rates was similar with connection to the UASB, giving 82% and 88% volatile solids destruction respectively. This suggests that the most efficient leaching condition is 1 dilution per day with connection to the UASB

  16. Cement based grouts - longevity laboratory studies: leaching behaviour

    International Nuclear Information System (INIS)

    This report describes a series of laboratory tests carried out to determine the possible leaching behaviour of cement-based grouts in repository environments. A reference high-performance cement-based grout, comprised of Canadian Type 50 (U.S. Type V) Sulphate Resisting Portland Cement, silica fume, potable water and superplasticizer, and a commercially available cement grout were subjected to leaching in distilled water and three simulated groundwaters of different ionic strength. Hardened, monolithic specimens of the grout were leached in static, pulsed-flow and continuous flow conditions at temperatures from 10 degrees C to 150 degrees C for periods of up to 56 days. The changes in concentration of ions in the leachants with time were determined and the changes in the morphology of the surfaces of the grout specimens were examined using electron microscopy. After a review of possible mechanisms of degradation of cement-based materials, the data from these experiments are presented. The data show that the grouts will leach when in contact with water through dissolution of more soluble phases. Comparison of the leaching performance of the two grouts indicates that, while there are some minor differences, they behaved quite similarly. The rate of the leaching processes were found to tend to decrease with time and to be accompanied by precipitation and/or growth of an assemblage of secondary alteration phases (i.e., CaCO3, Mg(OH)2). The mechanisms of leaching depended on the environmental conditions of temperature, groundwater composition and water flow rate. Matrix dissolution occurred. However, in many of the tests leaching was shown to be limited by the precipitated/reaction layers which acted as protective surface coatings. (37 refs.) (au)

  17. Improving hydrolysis of food waste in a leach bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Browne, James D.; Allen, Eoin; Murphy, Jerry D., E-mail: jerry.murphy@ucc.ie

    2013-11-15

    Highlights: • This paper assesses leaching of food waste in a two phase digestion system. • Leaching is assessed with and without an upflow anaerobic sludge blanket (UASB). • Without the UASB, low pH reduces hydrolysis, while increased flows increase leaching. • Inclusion of the UASB increases pH to optimal levels and greatly improves leaching. • The optimal conditions are suggested as low flow with connection to the UASB. - Abstract: This paper examines the rate of degradation of food waste in a leach bed reactor (LBR) under four different operating conditions. The effects of leachate recirculation at a low and high flow rate are examined with and without connection to an upflow anaerobic sludge blanket (UASB). Two dilution rates of the effective volume of the leach bed reactors were investigated: 1 and 6 dilutions per LBR per day. The increase in dilution rate from 1 to 6 improved the destruction of volatile solids without connection to the UASB. However connection to the UASB greatly improved the destruction of volatile solids (by almost 60%) at the low recirculation rate of 1 dilution per day. The increase in volatile solids destruction with connection to the UASB was attributed to an increase in leachate pH and buffering capacity provided by recirculated effluent from the UASB to the leach beds. The destruction of volatile solids for both the low and high dilution rates was similar with connection to the UASB, giving 82% and 88% volatile solids destruction respectively. This suggests that the most efficient leaching condition is 1 dilution per day with connection to the UASB.

  18. Information about radiographic films rejects of dental x-rays

    International Nuclear Information System (INIS)

    The purpose of this research was to qualify and quantify the number of dental x-ray films rejected in a Porto Alegre clinic. As we analyzed the captured data, it was concluded that, our of 1066 peri-apical films, we had a total percentage of 4.5% in relation to the total of the exams made. This 4.5% consists of the following rejects: placement, patient movement, technical errors, diaphragm, too much clarity in the result, double exposure, prolongation, shortness, darkened for not have been shot, superposed film. Because of that, the rejection, due to the bad placement of the film, is the one with the larger percentage value, i.e., 1.22% of the 4.5%. With the knowledge of the types of rejects and their causes, it was possible to correct some sources of systematic errors minimizing the repetition of the exams, saving costs, time and diminishing the ionizing radiation exposure for the patient, odontologist and his technical staff, which will be proved. (authors). 4 refs., 1 tab

  19. Peer Rejection Cues Induce Cardiac Slowing after Transition into Adolescence

    Science.gov (United States)

    Gunther Moor, Bregtje; Bos, Marieke G. N.; Crone, Eveline A.; van der Molen, Maurits W.

    2014-01-01

    The present study examined developmental and gender differences in sensitivity to peer rejection across the transition into adolescence by examining beat-by-beat heart rate responses. Children between the ages of 8 and 14 years were presented with unfamiliar faces of age-matched peers and were asked to predict whether they would be liked by the…

  20. Examining Appearance-Based Rejection Sensitivity during Early Adolescence

    Science.gov (United States)

    Bowker, Julie C.; Thomas, Katelyn K.; Spencer, Sarah V.; Park, Lora E.

    2013-01-01

    The present study of 150 adolescents ("M" age = 13.05 years) examined the associations between appearance-based rejection sensitivity (Appearance-RS) and psychological adjustment during early adolescence, and evaluated three types of other-gender peer experiences (other-gender friendship, peer acceptance, and romantic relationships) as…

  1. Duke power cities training, electrodes for low weld reject rate

    International Nuclear Information System (INIS)

    An intensive training program has allowed Duke Power Co. to achieve a reject rate of less than 1% in pipe and plate welds at its giant Catawba Nuclear Power Station, 30 miles southwest of Charlotte, NC. Constructed on a 418 acre site, the Catawba Station is scheduled to furnish 2240 megawatts of electricity from two reactors. Completion is set for 1983, and Duke will use around 208,000 lb (94,000 kg) of welding electrodes a year to complete the job. The reject rate on welding Schedule 40 pipe from 1 to 34 in. (2.5-86.4 cm) in diameter is 0.6%, and on carbon steel plate up to 3 in. (7.6 cm) thick the reject rate is 0.7%. In both instances the electrodes used are 0.045 in. (1.14 mm) Dual Shield 7000 (AWS E70T-1) and iron powder low hydrogen Atom Arc (AWS E7018). ''Intensive welder training no doubt has achieved such a high degree of success in low reject rates on our nuclear specification welds, but the welder must also have an electrode that has a certain amount of built-in ''forgiveness'' in the event of human oversight.''

  2. 48 CFR 619.505 - Rejecting Small Business Administration recommendations.

    Science.gov (United States)

    2010-10-01

    ... Small Business Administration recommendations. The Procurement Executive is the agency head for the... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Rejecting Small Business Administration recommendations. 619.505 Section 619.505 Federal Acquisition Regulations System DEPARTMENT...

  3. 48 CFR 1319.505 - Rejecting Small Business Administration recommendations.

    Science.gov (United States)

    2010-10-01

    ... Small Business Administration recommendations. (a) The designee authorized to render a decision on the Small Business Administration's appeal of the contracting officer's decision is set forth in CAM 1301.70... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Rejecting Small...

  4. Role of anti-vimentin antibodies in allograft rejection.

    Science.gov (United States)

    Rose, Marlene L

    2013-11-01

    Production of anti-vimentin antibodies (AVA) after solid organ transplantation are common. Although classically thought to be expressed mainly within the cytosol, recent evidence demonstrates that extracellular or cell surface expression of vimentin is not unusual. This review examines the evidence to assess whether AVA contribute to allograft pathology. Clinical studies suggest that AVA are associated with cardiac allograft vasculopathy in heart transplant recipients. Studies in non-human primates confirm that production of AVA after renal and heart transplantation are not inhibited by Cyclosporine. Experimental studies have demonstrated that mice pre-immunised with vimentin undergo accelerated acute rejection and vascular intimal occlusion of cardiac allografts. Adoptive transfer of hyperimmune sera containing AVA into B-cell-knock-out mice caused accelerated rejection of allografted hearts, this is clear evidence that antibodies to vimentin accelerate rejection. AVA act in concert with the alloimmune response and AVA do not damage syngeneic or native heart allografts. Confocal microscopy of allografted organs in vimentin immunised mice shows extensive expression of vimentin on endothelial cells, apoptotic leukocytes and platelet/leukocyte conjugates, co-localising with C4d. One explanation for the ability of AVA to accelerate rejection would be fixation of complement within the graft and subsequent pro-inflammatory effects; there may also be interactions with platelets within the vasculature.

  5. Compact filtering monopole patch antenna with dual-band rejection.

    Science.gov (United States)

    Kim, Sun-Woong; Choi, Dong-You

    2016-01-01

    In this paper, a compact ultra-wideband patch antenna with dual-band rejection is proposed. The proposed antenna filters 3.3-3.8 GHz WiMAX and 5.15-5.85 GHz WLAN by respectively rejecting these bands through a C-shaped slit and a λg/4 resonator. The λg/4 resonator is positioned as a pair, centered around the microstrip line, and a C-type slit is inserted into an elliptical patch. The impedance bandwidth of the proposed antenna is 2.9-9.3 GHz, which satisfies the bandwidth for ultra-wideband communication systems. Further, the proposed antenna provides dual-band rejection at two bands: 3.2-3.85 and 4.7-6.03 GHz. The radiation pattern of the antenna is omnidirectional, and antenna gain is maintained constantly while showing -8.4 and -1.5 dBi at the two rejected bands, respectively. PMID:27386331

  6. Nucleic Acid Drugs for Prevention of Cardiac Rejection

    Directory of Open Access Journals (Sweden)

    Jun-ichi Suzuki

    2009-01-01

    Full Text Available Heart transplantation has been broadly performed in humans. However, occurrence of acute and chronic rejection has not yet been resolved. Several inflammatory factors, such as cytokines and adhesion molecules, enhance the rejection. The graft arterial disease (GAD, which is a type of chronic rejection, is characterized by intimal thickening comprised of proliferative smooth muscle cells. Specific treatments that target the attenuation of acute rejection and GAD formation have not been well studied in cardiac transplantation. Recent progress in the nucleic acid drugs, such as antisense oligodeoxynucleotides (ODNs to regulate the transcription of disease-related genes, has important roles in therapeutic applications. Transfection of cis-element double-stranded DNA, named as “decoy,” has been also reported to be a useful nucleic acid drug. This decoy strategy has been not only a useful method for the experimental studies of gene regulation but also a novel clinical strategy. In this paper, we reviewed the experimental results of NF-κB, E2F, AP-1, and STAT-1 decoy and other ODNs using the experimental heart transplant models.

  7. Compact filtering monopole patch antenna with dual-band rejection.

    Science.gov (United States)

    Kim, Sun-Woong; Choi, Dong-You

    2016-01-01

    In this paper, a compact ultra-wideband patch antenna with dual-band rejection is proposed. The proposed antenna filters 3.3-3.8 GHz WiMAX and 5.15-5.85 GHz WLAN by respectively rejecting these bands through a C-shaped slit and a λg/4 resonator. The λg/4 resonator is positioned as a pair, centered around the microstrip line, and a C-type slit is inserted into an elliptical patch. The impedance bandwidth of the proposed antenna is 2.9-9.3 GHz, which satisfies the bandwidth for ultra-wideband communication systems. Further, the proposed antenna provides dual-band rejection at two bands: 3.2-3.85 and 4.7-6.03 GHz. The radiation pattern of the antenna is omnidirectional, and antenna gain is maintained constantly while showing -8.4 and -1.5 dBi at the two rejected bands, respectively.

  8. Rejected Manuscripts in Publishers' Archives: Legal Rights and Access

    Science.gov (United States)

    Hamburger, Susan

    2011-01-01

    This article focuses on an analysis of how various archival repositories deal with rejected manuscripts in publishers' archives as part of existing collections and as potential donations, and includes suggestions for ways to provide access while maintaining the author's legal rights. Viewpoints from the journal editor, author, archivist, and…

  9. Diffusion-based outlier rejection for underwater navigation

    DEFF Research Database (Denmark)

    Vike, Steinar; Jouffroy, Jerome

    This paper addresses the issue of rejecting spurious acoustic position measurements for the estimation of trajectories in underwater vehicle navigation. The method relies on the diffusion-based observer approach (Jouffroy and Opderbecke, 2004; 2005), which allows one to consider and process entire...

  10. Leaching of metals from cement under simulated environmental conditions.

    Science.gov (United States)

    Lu, Huixia; Wei, Fang; Tang, Jingchun; Giesy, John P

    2016-03-15

    Leaching of metals from cement under various environmental conditions was measured to evaluate their environmental safety. A cement product containing clinker, which was produced from cement kiln co-processing of hazardous wastes, was solidified and leaching of metals was characterized using the 8-period test. Concentrations and speciation of metals in cements were determined. Effects of ambient environment and particle size on leachability of metals and mineralogical phases of cement mortars were evaluated by use of XRD and SEM. Results indicated that metals in cements were leachable in various media in descending order of: sea water, groundwater and acid rain. Cr, Ni, As, Co and V were leached by simulated sea water, while Cu, Cd, Pb, Zn, Mn, Sb and Tl were not leached in simulated sea water, groundwater or acid rain. When exposed to simulated acid rain or groundwater, amounts of Cr, Ni, As and V leached was inversely proportional to particle size of cement mortar. According to the one-dimensional diffusion equation, Cr was most leachable and the cumulative leached mass was predicted to be 9.6 mg kg(-1) after 20 years. Results of this study are useful in predicting releases of metals from cement products containing ash and clinkers cement kiln co-processing of hazardous wastes, so that they can be safely applied in the environment.

  11. Leaching of Added Selenium in Soils Low in Native Selenium

    DEFF Research Database (Denmark)

    Nielsen, Gunnar Gissel; Hamdy, A. A.

    1977-01-01

    leaching took place within the 1st few days. In other experiments, selenite fixation in soils took several days to reach equilibrium. Leaching of the selenite added to mineral soils under Danish field conditions was insignificant in the short time-cycle of Se in the environment.......A soil column experiment was performed to evaluate the influence of organic matter and lime on the leaching and distribution of added selenite. 75Se-labeled Na2SeO3 was added to water-saturated soil columns with a diameter of 4.25 cm and a length of 16-20 cm. Leaching started immediately, one l...... water being added per column during the course of 1 wk. Most of the selenite did not move through the soil, and only a few per cent were found in the leaching water. Leaching was greatest in sandy soil. It was increased by the addition of lime, but decreased by addition of organic matter. Most of the...

  12. Study on leaching of refractory uranium in clay

    International Nuclear Information System (INIS)

    The leaching characteristcs of uranium-bearing clay of deposit A and other uranium deposits ar described. The causes of leaching refractoriness of the uranium in clay have been discussed. The research results show that the reason of leaching refractoriness of the uranium in clay is associated with recryctallization of clay minerals (including opel and goethite) during metamorphism of rocks. The probable course of forming refractory uranium in clay may be: adsorption of U+6 by clay minerals; reduction of U+6 to U+4; recrystalization of the clay mineral and U+4 exists at closed or semi-closed state in it. The results show that in order to leach the refractory uranium in clay, the uranium-bearing mineral should be made to produce new faultiness for reopening the passages into the mineral, thereby the uranium existing at closed or semi-closed state is exposed, and at the same time U+4 is oxidized to U+6. The middle-low temperature oxidation roasting, pressure alkaline leaching (160-180 deg C), and leaching with concentrated acid are efficient in treating the refractory type uranium ore

  13. Long-term leaching of uranium from different waste matrices.

    Science.gov (United States)

    Patra, A Chakrabarty; Sumesh, C G; Mohapatra, S; Sahoo, S K; Tripathi, R M; Puranik, V D

    2011-03-01

    A semi-dynamic leaching test was carried out for metallurgical wastes and ore samples from the uranium and copper mining industry over a 142 day period using distilled water and 0.1N NaNO(3) as solvents. Laser fluorimetry was used as the analytical technique to determine the total uranium content in the leachates. The cumulative leach fraction (CLF) of uranium release from the samples was calculated to be 0.22, 0.22, 0.07 and 0.39% for rock, uranium tailings, copper kinker ash samples and copper tailings respectively using distilled water as solvent and 0.31, 0.27, 0.05 and 0.59% for the same matrices using 0.1N NaNO(3). The release of mobile uranium fraction was very slow, being faster in the initial stage and then attained a near steady state condition. The diffusion coefficient and bulk release of uranium from the samples have been calculated. The processes governing the release of uranium from these matrices have been identified to be surface wash-off and diffusion. Hence the use of weak solvents (leach out the mobile/exchangeable fraction of uranium) under semi-dynamic conditions aids the determination of leaching parameters and identification of the leaching mechanism for mobile uranium fraction from different matrices by slow leaching processes. PMID:21084148

  14. Neutron diffraction studies for realtime leaching of catalytic Ni

    Energy Technology Data Exchange (ETDEWEB)

    Iles, Gail N., E-mail: gail.iles@helmholtz-berlin.de; Reinhart, Guillaume, E-mail: guillaume.reinhart@im2np.fr [European Space Agency, Keplerlaan 1, 2201 AZ Noordwijk (Netherlands); Institut Laue-Langevin, 6 rue Jules Horowitz, BP 156, 38042 Grenoble (France); European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP 220, 38043 Grenoble (France); Devred, François, E-mail: fdevred@ulb.ac.be [Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden (Netherlands); Henry, Paul F., E-mail: paul.henry@esss.se; Hansen, Thomas C., E-mail: hansen@ill.fr [Institut Laue-Langevin, 6 rue Jules Horowitz, BP 156, 38042 Grenoble (France)

    2014-07-21

    The leaching of Al from intermetallic samples of Nickel Aluminium alloys to form Raney-type nickel catalysts is widely used in the hydrogenation industry, however, little is known of the leaching process itself. In this study, the leaching of Al was measured in realtime, in situ, using the high-flux powder neutron diffractometer, D20, at the Institut Laue-Langevin. Despite the liberation of hydrogen and effervescent nature of the reaction the transformation of the dry powder phases into Raney-type Ni was determined. Samples produced by gas-atomisation were found to leach faster than those produced using the cast and crushed technique. Regardless of processing route of the precursor powder, the formation of spongy-Ni occurs almost immediately, while Ni{sub 2}Al{sub 3} and NiAl{sub 3} continue to transform over longer periods of time. Small-angle scattering and broadening of the diffraction peaks is an evidence for the formation of the smaller Ni particles. Understanding the kinetics of the leaching process will allow industry to refine production of catalysts for optimum manufacturing time while knowledge of leaching dynamics of powders produced by different manufacturing techniques will allow further tailoring of catalytic materials.

  15. Neutron diffraction studies for realtime leaching of catalytic Ni

    International Nuclear Information System (INIS)

    The leaching of Al from intermetallic samples of Nickel Aluminium alloys to form Raney-type nickel catalysts is widely used in the hydrogenation industry, however, little is known of the leaching process itself. In this study, the leaching of Al was measured in realtime, in situ, using the high-flux powder neutron diffractometer, D20, at the Institut Laue-Langevin. Despite the liberation of hydrogen and effervescent nature of the reaction the transformation of the dry powder phases into Raney-type Ni was determined. Samples produced by gas-atomisation were found to leach faster than those produced using the cast and crushed technique. Regardless of processing route of the precursor powder, the formation of spongy-Ni occurs almost immediately, while Ni2Al3 and NiAl3 continue to transform over longer periods of time. Small-angle scattering and broadening of the diffraction peaks is an evidence for the formation of the smaller Ni particles. Understanding the kinetics of the leaching process will allow industry to refine production of catalysts for optimum manufacturing time while knowledge of leaching dynamics of powders produced by different manufacturing techniques will allow further tailoring of catalytic materials

  16. Rejection of false saturation data in optical pulse-oximeter

    Science.gov (United States)

    Scalise, Lorenzo; Marchionni, Paolo; Carnielli, Virgilio

    2010-04-01

    Pulse oximetry (PO) is a non-invasive medical device used for monitoring of the arterial oxygen saturation (SaO2) and in particular of haemoglobin oxygenation in blood. Oxygen saturation is commonly used in any setting where the patient blood oxygen saturation is unstable, including Neonatal Intensive Care Unit (NICU). The main factor affecting PO's output data is the presence of voluntary or involuntary motion artifacts or imperfect skin-sensor contact. Various methods have been employed to reject motion artifact but have met with little success. The aim of the present work is to propose a novel measurement procedure for real-time monitoring and validation of the oxygen saturation data as measured in standard pulse oxymeter. The procedure should be able to individuate and reject erroneous saturation data due to incorrect transducer-skin contact or motion artifact. In the case of short sequences of rejected SpO2 data (time durationoximeter (HRSAT) and the SpO2 value. In order to remove the erroneous SpO2 values reported in the rough data in coincidence of motion artifact (top, right), we have implemented a specific algorithm which provides at the output a new sequence of SpO2 data (validated SpO2 data). With the aim to "rescue" SpO2 value rejected by the previously presented algorithm, we have implemented an algorithm able to provide the "most-probable" SpO2 values in the case of single rejected values or in the case of short sequences of invalidated data (oximeter are not validated by the use of our method (corresponding to a total time of 16 hr, 8min and 40s). The use of the proposed algorithm aiming to "rescue" data from short sequences of rejected data (< 8s) allows to increase the validated data of the 2.5%t(equivalent to 8hr, 40 min and 16s), allowing a percent of usable data of the 95.7%. Once implemented in clinic, it could be used to identify the period of the day in which the percent of rejected data increase or correlate this data to clinical procedure

  17. Fate of Manuscripts Rejected From the Red Journal

    International Nuclear Information System (INIS)

    Purpose: To evaluate characteristics associated with higher rates of acceptance for original manuscripts submitted for publication to the International Journal of Radiation Oncology • Biology • Physics (IJROBP) and describe the fate of rejected manuscripts. Methods and Materials: Manuscripts submitted to the IJROBP from May 1, 2010, to August 31, 2010, and May 1, 2012, to August 31, 2012, were evaluated for author demographics and acceptance status. A PubMed search was performed for each IJROBP-rejected manuscript to ascertain whether the manuscript was ultimately published elsewhere. The Impact Factor of the accepting journal and the number of citations of the published manuscript were also collected. Results: Of the 500 included manuscripts, 172 (34.4%) were accepted and 328 (65.6%) were rejected. There was no significant difference in acceptance rates according to gender or degree of the submitting author, but there were significant differences seen based on the submitting author's country, rank, and h-index. On multivariate analysis, earlier year submitted (P<.0001) and higher author h-index (P=.006) remained significantly associated with acceptance into the IJROBP. Two hundred thirty-five IJROBP-rejected manuscripts (71.7%) were ultimately published in a PubMed-listed journal as of July 2014. There were no significant differences in any submitting author characteristics. Journals accepting IJROBP-rejected manuscripts had a lower median [interquartile range] 2013 impact factor compared with the IJROBP (2.45 [1.53-3.71] vs 4.176). The IJROBP-rejected manuscripts ultimately published elsewhere had a lower median [interquartile range] number of citations (1 [0-4] vs 6 [2-11]; P<.001), which persisted on multivariate analysis. Conclusions: The acceptance rate for manuscripts submitted to the IJROBP is approximately one-third, and approximately 70% of rejected manuscripts are ultimately published in other PubMed-listed journals, but these ultimate

  18. Fate of Manuscripts Rejected From the Red Journal

    Energy Technology Data Exchange (ETDEWEB)

    Holliday, Emma B., E-mail: emmaholliday@gmail.com [Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Yang, George [The University of South Florida Morsani College of Medicine, Tampa, Florida (United States); Jagsi, Reshma [Department of Radiation Oncology, The University of Michigan, Ann Arbor, Michigan (United States); Hoffman, Karen E. [Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Bennett, Katherine Egan; Grace, Calley [Scientific Publications, American Society for Radiation Oncology, Fairfax, Virginia (United States); Zietman, Anthony L. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2015-01-01

    Purpose: To evaluate characteristics associated with higher rates of acceptance for original manuscripts submitted for publication to the International Journal of Radiation Oncology • Biology • Physics (IJROBP) and describe the fate of rejected manuscripts. Methods and Materials: Manuscripts submitted to the IJROBP from May 1, 2010, to August 31, 2010, and May 1, 2012, to August 31, 2012, were evaluated for author demographics and acceptance status. A PubMed search was performed for each IJROBP-rejected manuscript to ascertain whether the manuscript was ultimately published elsewhere. The Impact Factor of the accepting journal and the number of citations of the published manuscript were also collected. Results: Of the 500 included manuscripts, 172 (34.4%) were accepted and 328 (65.6%) were rejected. There was no significant difference in acceptance rates according to gender or degree of the submitting author, but there were significant differences seen based on the submitting author's country, rank, and h-index. On multivariate analysis, earlier year submitted (P<.0001) and higher author h-index (P=.006) remained significantly associated with acceptance into the IJROBP. Two hundred thirty-five IJROBP-rejected manuscripts (71.7%) were ultimately published in a PubMed-listed journal as of July 2014. There were no significant differences in any submitting author characteristics. Journals accepting IJROBP-rejected manuscripts had a lower median [interquartile range] 2013 impact factor compared with the IJROBP (2.45 [1.53-3.71] vs 4.176). The IJROBP-rejected manuscripts ultimately published elsewhere had a lower median [interquartile range] number of citations (1 [0-4] vs 6 [2-11]; P<.001), which persisted on multivariate analysis. Conclusions: The acceptance rate for manuscripts submitted to the IJROBP is approximately one-third, and approximately 70% of rejected manuscripts are ultimately published in other PubMed-listed journals, but these ultimate

  19. LEACHING OF SLAG FROM STEEL RECYCLING: RADIONUCLIDES AND STABLE ELEMENTS. DATA REPORT, JAN.15, 1997, REVISED SEPT.9, 1997

    Energy Technology Data Exchange (ETDEWEB)

    FUHRMANN,M.SCHOONEN,M.

    2003-07-31

    Of primary importance to this study are releases of radionuclides from slags. However, releases of other constituents also provide valuable information on releases of elements that may be toxic (e.g. Cr) or that may be used as analogs for radionuclides (e.g. K for Cs). In addition, leaching of bulk constituents from the slag gives information on weathering rates of the bulk material that can be used to estimate releases of non-leachable elements. Consequently, we have examined leaching of: radionuclides from those sloags that contain them; bulk elemental constituents of the slags; anionic constituents; trace elements, through spot checks of concentrations in leachates. Analysis by ICP of elemental constituents in leachates from radioactive samples was limited to those leachate samples that contained no detectable radionuclides, to avoid contamination of the ICP. In this data report we present leaching results for five slags that were produced by recycling steel. Two of the slags were generated at facilities that treat radioactively contaminated scrap, consequently the slag contains radionuclides. The slag from the other three was not contaminated. Because of this, we were able to examine the chemical composition of the slag and of the leachate generated during tests of these slags. For these materials we believe that leach rates of the stable elements can be used as analogs for radionuclides if the same steel processing method were used for radioactive material.

  20. Reuse of cement-solidified municipal incinerator fly ash in cement mortars: physico-mechanical and leaching characteristics.

    Science.gov (United States)

    Cinquepalmi, Maria Anna; Mangialardi, Teresa; Panei, Liliana; Paolini, Antonio Evangelista; Piga, Luigi

    2008-03-01

    The reuse of cement-solidified Municipal Solid Waste Incinerator (MSWI) fly ash (solidified/stabilised (S/S) product) as an artificial aggregate in Portland cement mortars was investigated. The S/S product consisted of a mixture of 48 wt.% washed MSWI fly ash, 20 wt.% Portland cement and 32 wt.% water, aged for 365 days at 20 degrees C and 100% RH. Cement mortars (water/cement weight ratio=0.62) were made with Portland cement, S/S product and natural sand at three replacement levels of sand with S/S product (0%, 10% and 50% by mass). After 28 days of curing at 20 degrees C and 100% RH, the mortar specimens were characterised for their physico-mechanical (porosity, compressive strength) and leaching behaviour. No retardation in strength development, relatively high compressive strengths (up to 36 N/mm2) and low leaching rates of heavy metals (Cr, Cu, Pb and Zn) were always recorded. The leaching data from sequential leach tests on monolithic specimens were successfully elaborated with a pseudo-diffusional model including a chemical retardation factor related to the partial dissolution of contaminant.